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Title:
METHODS AND DEVIVES FOR CONDITIONAL INCLUSION OF RANDOM ACCESS INFORMATION IN SECONDARY CELL GROUP (SCG) FAILURE INFORMATION N
Document Type and Number:
WIPO Patent Application WO/2023/153975
Kind Code:
A1
Abstract:
Embodiments include methods for a user equipment, UE, configured with a master cell group, MCG, and a secondary cell group, SCG, in a radio access network, RAN. Such methods include detecting (1310) a failure of the SCG and determining (1320) whether the SCG failure is any one of a plurality of predetermined failure types. Such methods include selectively including (1330) available random access, RA, information in an SCG failure information report based on determining (1332) that the SCG failure is one of the predetermined failure types, and sending (1340) the SCG failure information report to a RAN node. Other embodiments include complementary methods for a RAN node, as well as UEs and RAN nodes configured to perform such methods.

Inventors:
BELLESCHI MARCO (SE)
RAMACHANDRA PRADEEPA (SE)
TORABIAN ESFAHANI TAHMINEH (SE)
Application Number:
PCT/SE2023/050038
Publication Date:
August 17, 2023
Filing Date:
January 16, 2023
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
ERICSSON TELEFON AB L M (SE)
International Classes:
H04W76/19; H04W24/10; H04W36/30; H04W74/00; H04W76/15
Domestic Patent References:
WO2021161249A12021-08-19
WO2021162870A12021-08-19
Other References:
HUAWEI (EMAIL RAPPORTEUR): "Report of [Post115-e][897][SON/MDT] Modeling aspects related", vol. RAN WG2, no. Online; 20211101 - 20211112, 22 October 2021 (2021-10-22), XP052067082, Retrieved from the Internet [retrieved on 20211022]
"3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Radio Resource Control (RRC) protocol specification (Release 16)", vol. RAN WG2, no. V16.7.0, 23 December 2021 (2021-12-23), pages 1 - 963, XP052083424, Retrieved from the Internet [retrieved on 20211223]
3GPP TR 38.804
3GPP TS 36.300
3GPP TS 38.300
3GPP TS 36.331
3GPP TS 38.423
3GPP TS 38.331
Attorney, Agent or Firm:
AYOUB, Nabil (SE)
Download PDF:
Claims:
CLAIMS

1. A method for a user equipment, UE, configured with a master cell group, MCG, and a secondary cell group, SCG, in a radio access network, RAN, the method comprising: detecting (1310) a failure of the SCG; determining (1320) whether the SCG failure is any one of a plurality of predetermined failure types; selectively including (1330) available random access, RA, information in an SCG failure information report based on determining that the SCG failure is one of the predetermined failure types; and sending (1340) the SCG failure information report to a RAN node.

2. The method of claim 1, wherein selectively including (1330) available RA information in an SCG failure report comprises including (1331) a subset of the available RA information in the SCG failure report based on which one of the predetermined failure types is associated with the SCG failure.

3. The method of claim 2, wherein the subset of the available RA information is included in the SCG failure report based on determining that the SCG failure is a reconfiguration with sync failure in the SCG.

4. The method of claim 2, wherein the subset of the available RA information is included in the SCG failure report based on determining that the SCG failure is a RA problem indicated by the UE’s medium access control, MAC, entity associated with the SCG, and a UE timer, T304, associated with the SCG was running when the SCG failure was detected.

5. The method of any of claims 2-4, wherein: the available RA information includes per-RA attempt information and frequency information associated with SCG RA resources used by the UE; and the subset of the available RA information includes the per-RA attempt information.

6. The method of any of claims 2-5, wherein when included in the SCG failure information report, the subset of the RA information is contained in a perRAInfoList information element, IE.

7. The method of any of claims 1-6, wherein the SCG failure information report indicates which one of the predetermined failure types is associated with the SCG failure.

8. The method of any of claims 1-7, wherein the plurality of predetermined failure types include a reconfiguration with sync failure in the SCG.

9. The method of any of claims 1-7, wherein the plurality of predetermined failure types include a RA problem indicated by the UE’s medium access control, MAC, entity associated with the SCG.

10. The method of any of claims 1-7, wherein the plurality of predetermined failure types include a failed recovery from a beam failure associated with the SCG.

11. The method of claims 1-10, wherein the RAN node provides the UE’s MCG.

12. A method for a radio access network, RAN, node configured to provide a master cell group, MCG, for a user equipment, UE, that is also configured with a secondary cell group, SCG, in the RAN, the method comprising: receiving (1410), from the UE, an SCG failure information report related to a failure detected by the UE in the SCG, wherein the SCG failure information report selectively includes a subset of random access, RA, information available at the UE, based on which one of a plurality of predetermined failure types is associated with the SCG failure.

13. The method of claim 12, wherein the SCG failure information report includes the subset of the available RA information when the SCG failure is a reconfiguration with sync failure.

14. The method of claim 12, wherein the SCG failure information report includes the subset of the available RA information when the SCG failure is a RA problem indicated by the UE’s medium access control, MAC, entity associated with the SCG and a UE timer, T304, associated with the SCG was running when the SCG failure was detected.

15. The method of any of claims 12-14, wherein: the available RA information includes per-RA attempt information and frequency information associated with SCG RA resources used by the UE; and the subset of the available RA information includes the per-RA attempt information.

16. The method of any of claims 12-15, wherein when included in the SCG failure information report, the subset of the available RA information is contained in a perRAInfoList information element, IE.

17. The method of any of claims 12-16, wherein the SCG failure information report indicates which one of the predetermined failure types is associated with the SCG failure.

18. The method of any of claims 12-17, wherein the plurality of predetermined failure types include a reconfiguration with sync failure in the SCG.

19. The method of any of claims 12-17, wherein the plurality of predetermined failure types include a RA problem indicated by the UE’s medium access control, MAC, entity associated with the SCG.

20. The method of any of claims 12-17, wherein the plurality of predetermined failure types include a failed recovery from a beam failure associated with the SCG.

21. The method of any of claims 12-20, further comprising determining (1420) whether the UE performed a RA procedure in a default bandwidth part, BWP, of the SCG based on whether the subset of the available RA information is included in the SCG failure information report.

22. A user equipment, UE (205, 310, 1512, 1600, 2006) configured to operate with a master cell group, MCG, and a secondary cell group, SCG, in a radio access network, RAN (199, 299, 1504), the UE comprising: communication interface circuitry (1612) configured to communicate with RAN nodes (100, 150, 210, 220, 320, 1510, 1700, 1902, 2004) that provide the MCG and the SCG; and processing circuitry (1602) operatively coupled to the communication interface circuitry, whereby the processing circuitry and the communication interface circuitry are configured to: detect a failure of the SCG; determine whether the SCG failure is any one of a plurality of predetermined failure types; selectively include available random access, RA, information in an SCG failure information report based on determining that the SCG failure is one of the predetermined failure types; and send the SCG failure information report to a RAN node.

23. The UE of claim 22, wherein the processing circuitry and the communication interface circuitry are further configured to perform operations corresponding to any of the methods of claims 2-11.

24. A user equipment, UE (205, 310, 1512, 1600, 2006) configured to operate with a master cell group, MCG, and a secondary cell group, SCG, in a radio access network, RAN (199, 299, 1504), the UE being further configured to: detect a failure of the SCG; determine whether the SCG failure is any one of a plurality of predetermined failure types; selectively include available random access, RA, information in an SCG failure information report based on determining that the SCG failure is one of the predetermined failure types; and send the SCG failure information report to a RAN node (100, 150, 210, 220, 320, 1510, 1700, 1902, 2004).

25. The UE of claim 24, being further configured to perform operations corresponding to any of the methods of claims 2-11.

26. A non-transitory, computer-readable medium (1610) storing computer-executable instructions that, when executed by processing circuitry (1602) of a user equipment, UE (205, 310, 1512, 1600, 2006) configured to operate with a master cell group, MCG, and a secondary cell group, SCG, in a radio access network, RAN (199, 299, 1504), configure the UE to perform operations corresponding to any of the methods of claims 1-10.

27. A computer program product (1614) comprising computer-executable instructions that, when executed by processing circuitry (1602) of a user equipment, UE (205, 310, 1512, 1600, 2006) configured to operate with a master cell group, MCG, and a secondary cell group, SCG, in a radio access network, RAN (199, 299, 1504), configure the UE to perform operations corresponding to any of the methods of claims 1-10.

28. A radio access network, RAN, node (100, 150, 210, 220, 320, 1510, 1700, 1902, 2004) configured to provide a master cell group, MCG, for a user equipment, UE (205, 310, 1512, 1600, 2006) that is also configured with a secondary cell group, SCG, in the RAN, the RAN node comprising: communication interface circuitry (1706, 1904) configured to communicate with the UE; and processing circuitry (1702, 1904) operatively coupled to the communication interface circuitry, whereby the processing circuitry and the communication interface circuitry are configured to: receive from the UE an SCG failure information report related to a failure detected by the UE in the SCG, wherein the SCG failure information report selectively includes a subset of random access, RA, information available at the UE, based on which one of a plurality of predetermined failure types is associated with the SCG failure.

29. The RAN node of claim 28, wherein the processing circuitry and the communication interface circuitry are further configured to perform operations corresponding to any of the methods of claims 13-21.

30. A radio access network, RAN, node (100, 150, 210, 220, 320, 1510, 1700, 1902, 2004) configured to provide a master cell group, MCG, for a user equipment, UE (205, 310, 1512, 1600, 2006) that is also configured with a secondary cell group, SCG, in the RAN, the RAN node being further configured to: receive from the UE an SCG failure information report related to a failure detected by the UE in the SCG, wherein the SCG failure information report selectively includes a subset of random access, RA, information available at the UE, based on which one of a plurality of predetermined failure types is associated with the SCG failure.

31. The RAN node of claim 30, being further configured to perform operations corresponding to any of the methods of claims 13-21.

32. A non-transitory, computer-readable medium (1704, 1904) storing computer-executable instructions that, when executed by processing circuitry (1702, 1904) of a radio access network, RAN, node (100, 150, 210, 220, 320, 1510, 1700, 1902, 2004) configured to provide a master cell group, MCG, for a user equipment, UE (205, 310, 1512, 1600, 2006) that is also configured with a secondary cell group, SCG, in the RAN, configure the RAN node to perform operations corresponding to any of the methods of claims 12-21.

33. A computer program product (1704a, 1904a) comprising computer-executable instructions that, when executed by processing circuitry (1702, 1904) of a radio access network, RAN, node (100, 150, 210, 220, 320, 1510, 1700, 1902, 2004) configured to provide a master cell group, MCG, for a user equipment, UE (205, 310, 1512, 1600, 2006) that is also configured with a secondary cell group, SCG, in the RAN, configure the RAN node to perform operations corresponding to any of the methods of claims 12-21.

Description:
METHODS AND DEVIVES FOR CONDITIONAL INCLUSION OF RANDOM ACCESS INFORMATION IN SECONDARY CELL GROUP (SCG) FAILURE INFORMATION

TECHNICAL FIELD

The present disclosure relates generally to wireless networks, and more specifically to techniques for user equipment (UEs) to provide reports about radio link failures (RLFs) in the wireless network, particularly with respect to random-access-related failures in the UE’s secondary cell group (SCG).

BACKGROUND

Long-Term Evolution (LTE) is an umbrella term for so-called fourth generation (4G) radio access technologies developed within the Third-Generation Partnership Project (3 GPP) and initially standardized in Release 8 (Rel-8) and Release 9 (Rel-9), also known as Evolved UTRAN (E-UTRAN). LTE is targeted at various licensed frequency bands and is accompanied by improvements to non-radio aspects commonly referred to as System Architecture Evolution (SAE), which includes Evolved Packet Core (EPC) network. LTE continues to evolve through subsequent releases.

Currently the fifth generation (“5G”) of cellular systems, also referred to as New Radio (NR), is being standardized within 3GPP. NR is developed for maximum flexibility to support multiple and substantially different use cases. These include enhanced mobile broadband (eMBB), machine type communications (MTC), ultra-reliable low latency communications (URLLC), side-link device-to-device (D2D), and several other use cases.

Figure 1 illustrates an exemplary high-level view of a 5G network architecture, including a Next Generation RAN (NG-RAN) 199 and a 5G Core (5GC) 198. NG-RAN 199 can include a set of gNodeB’s (gNBs) connected to the 5GC via one or more NG interfaces, such as gNBs 100, 150 connected via interfaces 102, 152, respectively. In addition, the gNBs can be connected to each other via one or more Xn interfaces, such as Xn interface 140 between gNBs 100 and 150. With respect the NR interface to UEs, each of the gNBs can support frequency division duplexing (FDD), time division duplexing (TDD), or a combination thereof.

NG-RAN 199 is layered into a Radio Network Layer (RNL) and a Transport Network Layer (TNL). The NG-RAN architecture, /.< ., the NG-RAN logical nodes and interfaces between them, is defined as part of the RNL. For each NG-RAN interface (NG, Xn, Fl) the related TNL protocol and the functionality are specified. The TNL provides services for user plane transport and signaling transport.

The NG RAN logical nodes shown in Figure 1 include a central (or centralized) unit (CU or gNB-CU) and one or more distributed (or decentralized) units (DU or gNB-DU). For example, gNB 100 includes gNB-CU 110 and gNB-DUs 120 and 130. CUs (e.g., gNB-CU 110) are logical nodes that host higher-layer protocols and perform various gNB functions such controlling the operation of DUs. Each DU is a logical node that hosts lower-layer protocols and can include, depending on the functional split, various subsets of the gNB functions. As such, each of the CUs and DUs can include various circuitry needed to perform their respective functions, including processing circuitry, transceiver circuitry (e.g., for communication), and power supply circuitry.

A gNB-CU connects to gNB-DUs over respective Fl logical interfaces, such as interfaces 122 and 132 shown in Figure 1. The gNB-CU and connected gNB-DUs are only visible to other gNBs and the 5GC as a gNB. In other words, the Fl interface is not visible beyond gNB-CU.

Figure 2 shows another high-level view of an exemplary 5G network architecture, including a NG-RAN 299 and 5GC 298. As shown in the figure, NG-RAN 299 can include gNBs (e.g., 210a,b) and ng-eNBs (e.g., 220a, b) that are interconnected with each other via respective Xn interfaces. The gNBs and ng-eNBs are also connected via the NG interfaces to 5GC 298, more specifically to access and mobility management functions (AMFs, e.g., 230a, b) via respective NG- C interfaces and to user plane functions (UPFs, e.g., 240a, b) via respective NG-U interfaces. Moreover, the AMFs can communicate with one or more policy control functions (PCFs, e.g., 250a, b) and network exposure functions (NEFs, e.g., 260a, b).

Each of the gNBs can support the NR radio interface including frequency division duplexing (FDD), time division duplexing (TDD), or a combination thereof. Each of ng-eNBs can support the fourth generation (4G) Long-Term Evolution (LTE) radio interface. Unlike conventional LTE eNBs, however, ng-eNBs connect to the 5GC via the NG interface. Each of the gNBs and ng-eNBs can serve a geographic coverage area including one more cells, such as cells 21 la-b and 221a-b shown in Figure 2. Depending on the cell in which it is located, a UE 205 can communicate with the gNB or ng-eNB serving that cell via the NR or LTE radio interface, respectively. Although Figure 2 shows gNBs and ng-eNBs separately, it is also possible that a single NG-RAN node provides both types of functionality.

LTE Rel-12 introduced dual connectivity (DC) whereby a UE in RRC CONNECTED state (described in more detail below) can be connected to two network nodes simultaneously, thereby improving connection robustness and/or capacity. In LTE DC, these two network nodes are referred to as “Master eNB” (MeNB) and “Secondary eNB” (SeNB), or more generally as master node (MN) and secondary node (SN). More specifically, a UE is configured with a Master Cell Group (MCG) associated with MN and a Secondary Cell Group (SCG) associated with SN.

3GPP TR 38.804 (vl4.0.0) describes various exemplary DC scenarios or configurations in which the MN and SN can apply NR, LTE, or both. For example, EN-DC refers to the scenario where the MN (eNB) employs LTE and the SN (gNB) employs NR, and both are connected to an LTE Evolved Packet Core (EPC). Other multi-RAT (MR) DC scenarios are possible in the network architecture shown in Figure 2.

Seamless handovers are a key feature of 3GPP technologies. A UE is handed over from a source or serving cell, provided by a source node, to a target cell provided by a target node. Successful handovers ensure that the UE moves around in the coverage area of different cells without causing too many interruptions in the data transmission.

However, handover can have various problems related to robustness. For example, a handover command (e.g., RRCConnectionReconfiguration with mobilityControlInfo or RRCReconfiguration with a reconfigurationWithSync) is normally sent when the radio conditions for the UE are already quite bad and may not reach the UE before the UE’s degraded connection with the source node/cell is dropped. This causes the UE to declare radio link failure (RLF) or handover failure (HOF). Similarly, the UE may experience failure when trying to reestablish a failed connection with the network, causing the UE to declare connection establishment failure (CEF). When a UE is arranged in DC with an MCG and an SCG, such failures can occur in either the MCG or the SCG.

Various UE failure reporting procedures were introduced as part of the mobility robustness optimization (MRO) in LTE Rel-9. In these procedures, UEs log relevant information at the time of failure (e.g., RLF) and later report such information to the network via target cells to which UEs ultimately connect (e.g., after reestablishment). The reported information can include RRM measurements of various neighbor cells prior to the mobility operation (e.g., handover). When the UE experiences a failure (e.g., RLF or HOF) in the SCG, the UE sends an SCGFailur eInformation message to the network with information about the failure.

SUMMARY

Various additions to the SCGFailurelnformation message have been discussed as part of the work on 3GPP Rel-17. One possible addition is random access (RA) information associated with an RLF or an HOF in the SCG. Although this information can be useful for MRO, it significantly increases the size of the SCGFailurelnformation message, which is very undesirable. Better ways to report RA information associated with an RLF or an HOF in the SCG are needed.

Embodiments of the present disclosure provide specific improvements to failure reporting by UEs in a wireless network, such as by providing, enabling, and/or facilitating solutions to exemplary problems summarized above and described in more detail below.

Embodiments include methods (e.g., procedures) for a UE configured with an MCG and an SCG in a RAN. These exemplary methods can include detecting a failure of the SCG and determining whether the SCG failure is any one of a plurality of predetermined failure types. These exemplary methods can also include selectively including available RA information in an SCG failure information report based on determining that the SCG failure is one of the predetermined failure types. These exemplary methods can also include sending the SCG failure information report to a RAN node (e.g., the RAN node that provides the UE’s MCG).

In some embodiments, selectively including RA information can include including a subset of the available RA information in the SCG failure report based on which one of the predetermined failure types is associated with the SCG failure.

In some of these embodiments, the subset of the available RA information is included in the SCG failure report based on determining that the SCG failure is reconfiguration with sync failure in the SCG. In some of these embodiments, the subset of the available RA information is included in the SCG failure report based on determining that the SCG failure is a RA problem indicated by the UE’s medium access control (MAC) entity associated with the SCG and that a timer (T304) associated with the SCG was running when the SCG failure was detected.

In some embodiments, the available RA information includes per-RA attempt information and frequency-related information, and the subset of the available RA information includes the includes per-RA attempt information. In some of these embodiments, when included in the SCG failure information report, the subset is contained in a perRAInfoList information element (IE).

In some embodiments, the SCG failure information report indicates which one of the predetermined failure types is associated with the SCG failure. In some of these embodiments, the plurality of predetermined failure types include a reconfiguration with sync failure in the SCG. In some of these embodiments, the plurality of predetermined failure types include a RA problem indicated by the UE’s MAC entity associated with the SCG. In some of these embodiments, the plurality of predetermined failure types include a failed recovery from a beam failure associated with the SCG.

Other embodiments include methods (e.g., procedures) for a RAN node configured to provide an MCG for a UE that is also configured with an SCG in the RAN. These exemplary methods are generally complementary to the exemplary methods summarized above.

These exemplary methods can include receiving from the UE an SCG failure information report related to a failure detected by the UE in the SCG. The SCG failure information report selectively includes a subset of RA information available at the UE, based on which one of a plurality of predetermined failure types is associated with the SCG failure.

In some embodiments, the SCG failure information report includes the subset of the available RA information when one of the following applies: • the SCG failure is a reconfiguration with sync failure; or

• the SCG failure is a RA problem and a timer (T304) associated with the SCG was running when the SCG failure was detected.

In some embodiments, the available RA information includes per-RA attempt information and frequency-related information, and the subset of the available RA information includes the includes per-RA attempt information. In some of these embodiments, when included in the SCG failure information report, the subset of the available RA information is contained in a perRAInfoList IE.

In some embodiments, the SCG failure information report indicates which one of the predetermined failure types is associated with the SCG failure. In some embodiments, the plurality of predetermined failure types include at least one of the following:

• a reconfiguration with sync failure in the SCG;

• a RA problem indicated by the UE’s MAC entity associated with the SCG; and

• a failed recovery from a beam failure associated with the SCG.

In some embodiments, these exemplary methods can also include determining whether the UE performed a RA procedure in a default BWP of the SCG based on whether the subset of the available RA information is included in the SCG failure information report.

Other embodiments include UEs (e.g., wireless devices, etc.) and RAN nodes (e.g., base stations, eNBs, gNBs, ng-eNBs, TRPs, etc. configured to perform operations corresponding to any of the exemplary methods described herein. Other embodiments include non-transitory, computer-readable media storing program instructions that, when executed by processing circuitry, configure such UEs or RAN nodes to perform operations corresponding to any of the exemplary methods described herein.

At a high level, these and other embodiments described herein can reduce the size of an SCGFailur eInformation message by restricting when certain available RA information is included in the message. This improves the robustness of transmission of SCGFailur eInformation to the MN, reduces UE energy consumption, and reduces load on network resources. Embodiments can provide similar advantages when used to reduce the size of MCGFailur eInformation messages sent by a UE.

These and other objects, features, and advantages of embodiments of the present disclosure will become apparent upon reading the following Detailed Description in view of the Drawings briefly described below.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1-2 illustrate two high-level views of an exemplary 5G/NR network architecture. Figure 3 shows an exemplary configuration of NR user plane (UP) and control plane (CP) protocol stacks.

Figures 4A-B illustrate some reasons why handover of a UE may be unsuccessful.

Figure 5 illustrates 3GPP self-organizing network (SON) functionality.

Figures 6-7 illustrate various aspects of UE’s operation during an exemplary radio link failure (RLF) procedure in LTE and NR.

Figures 8A-B show exemplary ASN.1 data structures for an RA-InformationCommon-rl6 information element (IE) and certain fields or IES included therein.

Figure 9 shows an ASN.l data structure for an SCGFailurelnformation message.

Figures 10-12 show ASN.l data structures for various exemplary SCGFailurelnformation messages, according to various embodiments of the present disclosure.

Figure 13 shows a flow diagram of an exemplary method (e.g., procedure) for a UE, according to various embodiments of the present disclosure.

Figure 14 shows a flow diagram of an exemplary method (e.g., procedure) for a RAN node (e.g., base station, eNB, gNB, ng-eNB, etc.), according to various embodiments of the present disclosure.

Figure 15 shows a communication system according to various embodiments of the present disclosure.

Figure 16 shows a UE according to various embodiments of the present disclosure.

Figure 17 shows a network node according to various embodiments of the present disclosure.

Figure 18 shows host computing system according to various embodiments of the present disclosure.

Figure 19 is a block diagram of a virtualization environment in which functions implemented by some embodiments of the present disclosure may be virtualized.

Figure 20 illustrates communication between a host computing system, a network node, and a UE via multiple connections, at least one of which is wireless, according to various embodiments of the present disclosure.

DETAILED DESCRIPTION

Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided as examples to convey the scope of the subject matter to those skilled in the art. Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods and/or procedures disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein can be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments can apply to any other embodiments, and vice versa. Other objects, features, and advantages of the enclosed embodiments will be apparent from the following description.

Furthermore, the following terms are used throughout the description given below:

• Radio Access Node: As used herein, a “radio access node” (or equivalently “radio network node,” “radio access network node,” or “RAN node”) can be any node in a radio access network (RAN) that operates to wirelessly transmit and/or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g., gNB in a 3 GPP 5G/NR network or an enhanced or eNB in a 3GPP LTE network), base station distributed components (e.g., CU and DU), a high-power or macro base station, a low-power base station (e.g., micro, pico, femto, or home base station, or the like), an integrated access backhaul (IAB) node, a transmission point (TP), a transmission reception point (TRP), a remote radio unit (RRU or RRH), and a relay node.

• Core Network Node: As used herein, a “core network node” is any type of node in a core network. Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a serving gateway (SGW), a PDN Gateway (P-GW), a Policy and Charging Rules Function (PCRF), an access and mobility management function (AMF), a session management function (SMF), a user plane function (UPF), a Charging Function (CHF), a Policy Control Function (PCF), an Authentication Server Function (AUSF), a location management function (LMF), or the like.

• Wireless Device: As used herein, a “wireless device” (or “WD” for short) is any type of device that is capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Communicating wirelessly can involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air. Unless otherwise noted, the term “wireless device” is used interchangeably herein with the term “user equipment” (or “UE” for short), with both of these terms having a different meaning than the term “network node”.

• Radio Node: As used herein, a “radio node” can be either a “radio access node” (or equivalent term) or a “wireless device.”

• Network Node: As used herein, a “network node” is any node that is either part of the radio access network (c.g, a radio access node or equivalent term) or of the core network (c.g, a core network node discussed above) of a cellular communications network. Functionally, a network node is equipment capable, configured, arranged, and/or operable to communicate directly or indirectly with a wireless device and/or with other network nodes or equipment in the cellular communications network, to enable and/or provide wireless access to the wireless device, and/or to perform other functions (e.g., administration) in the cellular communications network.

• Base station: As used herein, a “base station” may comprise a physical or a logical node transmitting or controlling the transmission of radio signals, e.g., eNB, gNB, ng-eNB, en- gNB, centralized unit (CU)/distributed unit (DU), transmitting radio network node, transmission point (TP), transmission reception point (TRP), remote radio head (RRH), remote radio unit (RRU), Distributed Antenna System (DAS), relay, etc.

• Node: As used herein, the term “node” (without prefix) can be any type of node that can in or with a wireless network (including RAN and/or core network), including a radio access node (or equivalent term), core network node, or wireless device. However, the term “node” may be limited to a particular type (e.g., radio access node) based on its specific characteristics in any given context.

The above definitions are not meant to be exclusive. In other words, various ones of the above terms may be explained and/or described elsewhere in the present disclosure using the same or similar terminology. Nevertheless, to the extent that such other explanations and/or descriptions conflict with the above definitions, the above definitions should control.

Note that the description given herein focuses on a 3 GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system. Furthermore, although the term “cell” is used herein, it should be understood that (particularly with respect to 5G NR) beams may be used instead of cells and, as such, concepts described herein apply equally to both cells and beams.

Figure 3 shows an exemplary configuration of NR user plane (UP) and control plane (CP) protocol stacks between a UE (310), a gNB (320), and an AMF (330), such as those shown in Figures 1-2. The Physical (PHY), Medium Access Control (MAC), Radio Link Control (RLC), and Packet Data Convergence Protocol (PDCP) layers between the UE and the gNB are common to UP and CP. The PDCP layer provides ciphering/deciphering, integrity protection, sequence numbering, reordering, and duplicate detection for both CP and UP. In addition, PDCP provides header compression and retransmission for UP data.

On the UP side, Internet protocol (IP) packets arrive to the PDCP layer as service data units (SDUs), and PDCP creates protocol data units (PDUs) to deliver to RLC. The Service Data Adaptation Protocol (SDAP) layer handles quality-of-service (QoS) including mapping between QoS flows and Data Radio Bearers (DRBs) and marking QoS flow identifiers (QFI) in UU and DL packets. The RLC layer transfers PDCP PDUs to the MAC through logical channels (LCH). RLC provides error detection/correction, concatenation, segmentation/reassembly, sequence numbering, reordering of data transferred to/from the upper layers. The MAC layer provides mapping between LCHs and PHY transport channels, LCH prioritization, multiplexing into or demultiplexing from transport blocks (TBs), hybrid ARQ (HARQ) error correction, and dynamic scheduling (on gNB side). The PHY layer provides transport channel services to the MAC layer and handles transfer over the NR radio interface, e.g., via modulation, coding, antenna mapping, and beam forming.

On CP side, the non-access stratum (NAS) layer is between UE and AMF and handles UE/gNB authentication, mobility management, and security control. The RRC layer sits below NAS in the UE but terminates in the gNB rather than the AMF. RRC controls communications between UE and gNB at the radio interface as well as the mobility of a UE between cells in the NG-RAN. RRC also broadcasts system information (SI) and performs establishment, configuration, maintenance, and release of DRBs and Signaling Radio Bearers (SRBs) and used by UEs. Additionally, RRC controls addition, modification, and release of carrier aggregation (CA) and dual -connectivity (DC) configurations for UEs. RRC also performs various security functions such as key management.

After a UE is powered ON it will be in the RRC IDLE state until an RRC connection is established with the network, at which time the UE will transition to RRC CONNECTED state (e.g., where data transfer can occur). The UE returns to RRC IDLE after the connection with the network is released. In RRC IDLE state, the UE’s radio is active on a discontinuous reception (DRX) schedule configured by upper layers. During DRX active periods (also referred to as “DRX On durations”), an RRC IDLE UE receives SI broadcast in the cell where the UE is camping, performs measurements of neighbor cells to support cell reselection, and monitors a paging channel on PDCCH for pages from 5GC via gNB. An NR UE in RRC IDLE state is not known to the gNB serving the cell where the UE is camping. However, NR RRC includes an RRC INACTIVE state in which a UE is known (e.g., via UE context) by the serving gNB. RRC INACTIVE has some properties similar to a “suspended” condition used in LTE.

As mentioned above, LTE Rel-12 introduced dual connectivity (DC) whereby a LE in RRC CONNECTED state can be connected to two network nodes simultaneously, thereby improving connection robustness and/or capacity. In LTE DC, these two network nodes are referred to as “Master eNB” (MeNB) and “Secondary eNB” (SeNB), or more generally as master node (MN) and secondary node (SN). More specifically, a UE is configured with a Master Cell Group (MCG) associated with MN and a Secondary Cell Group (SCG) associated with SN.

Each of these groups of serving cells include one MAC entity, a set of logical channels with associated RLC entities, a primary cell (PCell or PSCell), and optionally one or more secondary cells (SCells). The term “Special Cell” (or “SpCell” for short) refers to the PCell of the MCG or the PSCell of the SCG depending on whether the UE’s MAC entity is associated with the MCG or the SCG, respectively. In non-DC operation (e.g., carrier aggregation, CA), SpCell refers to the PCell. An SpCell is always activated and supports physical uplink control channel (PUCCH) transmission and contention-based random access (CBRA) by UEs.

The MN provides system information (SI) and terminates the control plane connection towards the UE and, as such, is the controlling node of the UE, including handovers to and from SNs. For example, the MN terminates the connection between the eNB and the MME for an LTE UE. An SN provides additional radio resources (e.g., bearers) for radio resource bearers include MCG bearers, SCG bearers, and split bearers that have resources from both MCG and SCG. The reconfiguration, addition, and removal of SCells can be performed by RRC. When adding a new SCell, dedicated RRC signaling is used to send the UE all required SI of the SCell, such that UEs need not acquire SI directly from the SCell broadcast. In addition, either or both of the MCG and the SCG can include multiple cells working in carrier aggregation (CA).

3GPP TR 38.804 (vl4.0.0) describes various exemplary DC scenarios or configurations in which the MN and SN can apply NR, LTE, or both. The following terminology is used to describe these exemplary DC scenarios or configurations:

• DC: LTE DC (i.e., both MN and SN employ LTE, as discussed above);

• EN-DC: LTE -NR DC where MN (eNB) employs LTE and SN (gNB) employs NR, and both are connected to EPC.

• NGEN-DC: LTE -NR dual connectivity where a UE is connected to one ng-eNB that acts as a MN and one gNB that acts as a SN. The ng-eNB is connected to the 5GC and the gNB is connected to the ng-eNB via the Xn interface. • NE-DC: LTE-NR dual connectivity where a UE is connected to one gNB that acts as a MN and one ng-eNB that acts as a SN. The gNB is connected to 5GC and the ng-eNB is connected to the gNB via the Xn interface.

• NR-DC (or NR-NR DC): both MN and SN employ NR.

• MR-DC (multi-RAT DC): a generalization of the Intra-E-UTRA Dual Connectivity (DC) described in 3GPP TS 36.300 (vl6.3.0), where a multiple Rx/Tx UE may be configured to utilize resources provided by two different nodes connected via non-ideal backhaul, one providing E-UTRA access and the other one providing NR access. One node acts as the MN and the other as the SN. The MN and SN are connected via a network interface and at least the MN is connected to the core network. EN-DC, NE-DC, and NGEN-DC are different example cases of MR-DC.

Seamless mobility is a key feature of 3GPP radio access technologies (RATs). In general, a network configures a UE to perform and report radio resource management (RRM) measurements to assist network-controlled mobility decisions, such as for handover from a serving cell to a neighbor cell while the UE is in RRC CONNECTED state. Seamless handovers ensure that the UE moves around in the coverage area of different cells without causing too many interruptions in data transmission.

During preparation for handover of a UE to a target node, the source node sends the current UE configuration to the target node in the HANDOVER REQUEST message. The target node prepares a target configuration for the UE based on the current configuration and the capabilities of the target node and the UE. The target node sends the target configuration to the source node in a HANDOVER REQUEST ACKNOWLEDGE message, which the source node encapsulates in an RRCReconfiguration message to the UE. As a streamlined option, the target configuration can be signaled as a “delta-configuration” including only the differences from the UE’s current configuration in the source cell.

Handovers are normally triggered when the UE is at the edge of a cell’s coverage and experiences poor radio conditions. Once the UE experiences such conditions, the network may be unable to receive a measurement report from the UE, such that the network will not initiate a handover procedure. Even if the network does receive measurement reports, the UE may be unable to receive the network’s handover command (i.e., RRCReconfiguration message with a reconfigurationWithSync field) due to poor DL radio conditions. Moreover, in poor radio conditions the DL message is often segmented, which increases the likelihood of retransmissions with associated delay. As such, even if the handover command reaches the UE, it may be too late. For these reasons, failed transmission of handover command is a common reason for unsuccessful handovers. Figure 4, which includes Figures 4A and 4B, illustrates various exemplary robustness problems that can occur during UE mobility operations, such as during a handover. In the scenario shown in Figure 4A, based on neighbor-cell measurements, the UE triggers an “A3 event” where the neighbor cell is better than the UE’s PCell. In response, the UE attempts to send a measurement report about this condition to the source (e.g., serving) node. Due to the rapidly degrading uplink radio conditions, however, the source node does not receive the measurement report from the UE. Conditions continue to degrade in the UE’s source cell, ultimately prompting the UE to declare RLF and attempt to reestablish a connection with the source node (which may or may not be successful). In Figure 4B, the source node correctly receives the UE’s measurement report but due to degrading downlink radio conditions, the UE does not receive the HO command from the source node. Ultimately, the same result occurs in both cases shown in Figure 4.

As such, there is a need to improve mobility robustness in NR systems, and 3GPP Rel-16 includes some features called mobility robustness optimization (MRO). The main objectives of MRO are to improve the robustness at handover and to decrease the interruption time at handover. One solution is called “conditional handover” (or “CHO” for short) or “early handover command.” In CHO, transmission and execution of the handover command are separated. This allows the handover command to be sent earlier to UE when the radio conditions are still good, thus increasing the likelihood that the message is successfully transferred. The execution of the handover command is done at later point in time based on an associated execution condition. The execution condition is typically in the form a threshold, e.g., signal strength of candidate target cell becomes X dB better than the serving cell (so-called A3 event) or signal strength of serving cell becomes worse than X dBm and signal strength of candidate target cell becomes better than Y dBm (so-called A5 event).

A preceding measurement reporting event could use a threshold Y that is selected to be lower than the one in the handover execution condition. This allows the serving cell to prepare the handover upon reception of an early measurement report and to provide the RRCConnectionReconfiguration with mobilityControlInfo (for LTE), or a RRCReconfiguration with either a reconfigurationWithSync or a CellGroupConfig (for NR) at a time when the radio link between the source cell and the UE is still relatively stable. The execution of the handover is done at a later point in time (and threshold) that is optimal and/or preferred for handover execution.

Self-Organizing Network (SON) functionality is intended to make planning, configuration, management, optimization, and healing of mobile RANs simpler and faster. SON functionality and behavior has been defined and specified in by organizations such as 3GPP and NGMN (Next Generation Mobile Networks). Figure 5 is a high-level diagram illustrating 3GPP’s division of SON functionality into a self-configuration process and a self-optimization process.

Self-configuration is a pre-operational process in which newly deployed nodes (e.g., eNBs or gNBs in a pre-operational state) are configured by automatic installation procedures to get the necessary basic configuration for system operation. Pre-operational state generally refers to the time when the node is powered up and has backbone connectivity until the node’s RF transmitter is switched on. Self-configuration operations in pre-operational state include (A) basic setup and (B) initial radio configuration, and each includes various sub-operations as shown in Figure 5.

Self-optimization is a process in which UE and network measurements are used to autotune the network. This occurs when the nodes are in an operational state, which generally refers to the time when the node’s RF transmitter interface switched on. Self-configuration operations include optimization and adaptation, which include various sub-operations as shown in Figure 5.

Self-configuration and self-optimization features for LTE networks are described in 3 GPP TS 36.300 (vl6.7.0) section 22.2. These include dynamic configuration, automatic neighbor relations (ANR), mobility load balancing (MLB), mobility robustness optimization (MRO), RACH optimization, and support for energy savings. Self-configuration and self-optimization features for NR networks are described in 3GPP TS 38.300 (vl6.8.0) section 15. Rel-15 features include dynamic configuration and ANR, with additional features such as MRO being specified for Rel-16.

Returning to discussion of RLF, a network can configure a LE in RRC CONNECTED state to perform and report RRM measurements that assist network-controlled mobility decisions such as LE handover between cells, SN change, etc. The LE may lose coverage in its current serving cell (e.g., PCell in DC) and attempt handover to a target cell. Similarly, a LE in DC may lose coverage in its current PSCell and attempt an SN change. Other events may trigger other mobility-related procedures.

An RLF procedure is typically triggered in the UE when something unexpected happens in any of these mobility-related procedures. The RLF procedure involves interactions between RRC and lower layer protocols such as PHY (or LI), MAC, REC, etc. including radio link monitoring (RLM) on LI.

The principle of RLM is similar in LTE and NR. In general, the LE monitors link quality of the LE’s serving cell (i.e., SpCell) and uses that information to decide whether the LE is insync (IS) or out-of-sync (OOS) with respect to that serving cell. In LTE, RLM is carried out by the LE measuring downlink reference signals (e.g., CRS) in RRC CONNECTED state. If RLM (i.e., by Ll/PHY) indicates number of consecutive OOS conditions to the LE RRC layer, then RRC starts a radio link failure (RLF) procedure and declares RLF after expiry of a timer (e.g., T310). The LI RLM procedure is carried out by comparing the estimated CRS measurements to some target block error rates (BLERs), called Qout and Qin. In particular, Qout and Qin correspond to BLER of hypothetical PDCCH/PCIFCH transmissions from the serving cell, with exemplary values of 10% and 2%, respectively. In NR, the network can define the RS type (e.g., CSLRS and/or SSB), exact resources to be monitored, and even the BLER target for IS and OOS indications.

Figure 6 shows a high-level timing diagram illustrating the two phases of an RLF procedure in LTE and NR. The first phase starts upon radio problem detection and leads to radio link failure detection after no recovery is made during a period Tl. The second phase starts upon RLF detection or handover failure and ends with the UE returning to RRC IDLE if no recovery is made during a period T2.

Figure 7 shows a more detailed version of the UE’s operations during an exemplary RLF procedure, such as for LTE or NR. In this example, the UE detects N310 consecutive OOS conditions during LI RLM procedures, as discussed above, and then initiates timer T310. Subsequent operations are performed by higher layers (e.g., RRC). After expiry of T310, the UE starts T311 and RRC reestablishment, searching for the best target cell. After selecting a target cell for reestablishment, the UE obtains system information (SI) for the target cell and performs a random access e.g., via RACH). The duration after T310 expiry until this point can be considered the UE’s reestablishment delay. Ultimately, the UE obtains access to the target cell and sends an RRC Reestablishment Request message to the target cell. The duration after T310 expiry until this point can be considered the total RRC reestablishment delay. If the UE does not successfully reestablish in a target cell before expiration of T311, the UE enters RRC IDLE and releases its connection to the network.

The timers and counters described above are further described in Tables 1-2 below, respectively. For NR-DC and NGEN-DC, T310 is used for both PCell/MCG and PSCell/SCG. For LTE-DC and NE-DC (i.e., where SN is eNB), T313 is used for PSCell/SCG. The UE reads the timer values from system information (SI) broadcast in the UE’s SpCell. Alternatively, the network can configure the UE with UE-specific values of the timers and constants via dedicated RRC signaling (i.e., specific values sent to specific UEs via respective messages). Table 1.

Table 2.

One reason for introducing the timers and counters listed above is to add some filtering, delay, and/or hysteresis to a UE’s determination of failure and/or recovery of a radio link with a serving cell. These parameters avoid a UE abandoning a connection prematurely due to a brief or temporary reduction in link quality that could be recovered by the UE (e.g., before T310 expires, before the counter value N310, etc.). In general, this improves user experience. In contrast to RLF described above, a UE declares handover failure (HOF) upon expiry of timer T304 while performing the handover to the target cell. In case of HOF or RLF, the UE may take autonomous actions to remain reachable by the network, such as selecting a cell and initiating reestablishment. In general, a UE declares RLF only when the UE realizes that there is no reliable communication channel (or radio link) available between itself and the network, which can result in poor user experience. Also, reestablishing the connection requires signaling with a newly selected cell (e.g., RA procedure, exchanging RRC messages, etc.), which introduces latency until the UE can again reliably transmit and/or receive user data with the network. According to 3GPP TS 36.331 (vl 5.7.0), some causes for RLF include:

1) Radio link problem indicated by PHY (e.g., expiry of RLM-related timer T310);

2) Random access problem indicated by MAC entity;

3) Expiry of a measurement reporting timer (e.g., T312), due to not receiving a HO command from the network while the timer is running despite sending a measurement report; and

4) Reaching a maximum number of REC retransmissions.

Since RLF leads to reestablishment in a new cell and degradation of UE/network performance and end-user experience, it is in the interest of the network to understand the reasons for UE RLF and to optimize mobility -related parameters (e.g., trigger conditions of measurement reports) to reduce, minimize, and/or avoid subsequent RLFs. Before Rel-9 mobility robustness optimizations (MRO), only the UE was aware of radio quality at the time of RLF, the actual reason for declaring RLF, etc. To identify the RLF cause, the network requires more information from the UE and from the neighboring base stations (e.g., eNBs).

An RLF reporting procedure was introduced as part of MRO for NR Rel-16. In this procedure, a UE logs relevant information at the time of RLF and later reports such information to the network via a target cell to which the UE ultimately connects (e.g., after reestablishment). The UE can store the RLF report in a UE variable call varRLF-Report and retains it in memory for up to 48 hours, after which it may discard the information.

When sending certain RRC messages such as RRCReconfigurationComplete, RRCReestablishmentComplete, RRCSetup-Complete, and RRCResumeComplete, the UE can indicate it has a stored RLF report by setting a rlf-InfoAvailable field to “true”. If the gNB serving the target cell wants to receive the RLF report, it sends the UE an UEInformationRequest message with a flag “rlf-ReportReq-rl6”. In response, the UE sends the gNB an UEInformationResponse message that includes the RLF report.

In general, the UE-reported RLF information can include any of the following:

• Measurement quantities (RSRP, RSRQ) of the last serving cell (PCell).

• Measurement quantities of the neighbor cells in different frequencies of different RATs (e.g., EUTRA, UTRA, GERAN, CDMA2000).

• Measurement quantity (RS SI) associated to WLAN APs. • Measurement quantity (RS SI) associated to Bluetooth beacons.

• Location information, if available (including location coordinates and velocity)

• Globally unique identity of the last serving cell, if available, otherwise the PCI and the carrier frequency of the last serving cell.

• Tracking area code of the PCell.

• Time elapsed since the last reception of the ‘Handover command’ message.

• Cell Radio Network Temporary Identifier (C-RNTI) used in the previous serving cell.

• Whether or not the UE was configured with a data radio bearer (DRB) having QCI = 1.

The RLF reporting procedure not only introduced new RRC signaling between UE and the network (e.g., a target gNB hosting the target cell), but also introduced signaling between nodes in the network (e.g., XnAP signaling specified in 3GPP TS 38.423). For example, a gNB receiving an RLF report could forward some or all of the report to the gNB in which the RLF originated. Two different types of inter-node messages have been standardized in in 3 GPP TS 38.423 for sending RLF reports between nodes: Failure indication and Handover report.

Based on the contents of the RLF report (e.g., a globally unique identity of the last serving cell), the node serving the target cell (i.e., the UE’s new serving cell) can determine the cell where the RLF originated and forward the RLF report to the source gNB serving that cell. Based on receiving this report, the node serving the UE’s source cell (i.e., where the RLF occurred) can deduce whether the RLF was caused due to a coverage hole or due to handover-related parameter configurations. If the RLF was deemed to be due to handover associated parameter configurations, the original serving cell can further classify the handover related failure as too-early, too-late, or handover to wrong cell classes.

The original serving cell can classify a handover failure to be ‘too late handover’ when the original serving cell fails to send the handover command to the UE associated to a handover towards a particular target cell and if the UE reestablishes itself in this target cell post RLF. An example corrective action from the original serving cell could be to initiate the handover procedure towards this target cell a bit earlier by decreasing the CIO (cell individual offset) towards the target cell that controls when the IE sends the event triggered measurement report that leads to taking the handover decision.

The original serving cell can classify a handover failure to be ‘too early handover’ when the original serving cell is successful in sending the handover command to the UE associated to a handover however the UE fails to perform the random access towards this target cell. An example corrective action from the original serving cell could be to initiate the handover procedure towards this target cell a bit later by increasing the CIO (cell individual offset) towards the target cell that controls when the IE sends the event triggered measurement report that leads to taking the handover decision.

The original serving cell can classify a handover failure to be ‘handover-to-wrong-cell’ when the original serving cell intends to perform the handover for this UE towards a particular target cell, but the UE declares the RLF and reestablishes itself in a third cell. A corrective action from the original serving cell could be to initiate the measurement reporting procedure that leads to handover towards the target cell a bit later by decreasing the CIO (cell individual offset) towards the target cell or via initiating the handover towards the cell in which the UE reestablished a bit earlier by increasing the CIO towards the reestablishment cell.

In addition to the timers listed in Table 1 above, a UE initiates timer T312 upon transmission of a measurement report associated with a measurement identity (measID) for which the timer T312 is configured and enabled by the network. Once initiated, the UE stops T312 when certain conditions are fulfilled, such as upon receiving N311 consecutive in-sync indications from lower layers for the SpCell or upon receiving/executing a HO command. Otherwise, when T312 expires the UE initiates a reestablishment procedure or transmits an MCG failure information or SCG failure information depending on whether the T312 expired for the MCG or SCG.

More specifically, T312 is initiated in the UE’s MCG upon triggering a measurement report for a measurement identity for which T312 has been configured and useT312 has been set to true, while T310 in PCell is running. Likewise, T312 is initiated in the UE’s SCG upon triggering a measurement report for a measurement identity for which T312 has been configured and useT312 has been set to true, while T310 in PSCell is running. T312 is stopped upon any of the following conditions:

• receiving N311 consecutive in-sync indications from lower layers for the SpCell,

• receiving RRCReconfiguration with reconfigurationWithSync for that cell group,

• reception of MobilityFromNRCommand,

• initiating the connection re-establishment procedure,

• reconfiguration of rlf-TimersAndConstant,

• initiating the MCG failure information procedure,

• conditional reconfiguration execution, i.e., when applying a stored RRCReconfiguration message including reconfigurationWithSync for that cell group,

• expiry of T310 in corresponding SpCell, and

• SCG release, if T312 is kept in SCG.

Upon expiration of T312 kept in MCG, the UE initiates an MCG failure information procedure (specified in 3GPP TS 38.331 (vl6.7.0) section 5.7.3b) or the connection reestablishment procedure. In such case, the UE sends an SCGFailurelnformation message Upon expiration of T312 kept in SCG, the UE Informs E-UTRAN/NR about the SCG RLF by initiating the SCG failure information procedure (specified in 3GPP TS 38.331 (vl6.7.0) section 5.7.3), during which the UE sends an SCGFailur eInformation message.

In both LTE and NR, a UE can perform a random-access (RA) procedure towards the network (e.g., gNB) in any of the following scenarios, events, and/or conditions:

• Initial access to establish a connection from RRC IDLE state;

• During an RRC connection re-establishment procedure;

• During handover (i.e., change in serving cell while in RRC CONNECTED state);

• Upon arrival of DL data while in RRC CONNECTED state (as needed); and

• Upon arrival of uplink (UL) data while in RRC CONNECTED state (as needed, e.g., when the UE’s UL is non-synchronized with the network and/or there are no PUCCH resources available for transmitting a scheduling request, SR).

Conventionally, UEs perform contention-based random-access (CBRA) in which initial transmissions (also referred to as “preambles,” “sequences,” or “msgl”) via a random access channel (RACH) can collide with initial transmissions from other UEs attempting to access the same cell via the same RACH. Note that RACH is an UL transport layer channel that is based on a physical RACH (PRACH) provided by the PHY. When such collisions occur, the network may not correctly receive a UE’s random-access preamble transmissions, causing the UE to attempt retransmission at a higher power level. One way to avoid collisions is by contention-free random access (CFRA), in which the UE uses PRACH resources previously assigned to the UE by the gNB serving the cell.

RACH configuration impacts user experience and overall network performance. RACH configuration often affects collision probability, which in turn affects access setup delays, delays in resuming from UL unsynchronized state, handover delays, transition delays from RRC INACTIVE, and beam failure recovery delays. In addition, performing RACH on the most suitable DL beam is also important and will avoid unnecessary power ramping and failed RACH attempts. Consequently, this avoids unnecessary interference in the network and reduces delay and energy consumption as experience by UEs.

Various additions to the SCGFailurelnformation message have been discussed as part of the work on 3GPP Rel-17. One possible addition is RA information associated with an RLF or an HOF in the SCG. This RA information can be included, for example, when the failureType field in the message is set to “randomAccessProblem” or “beamFailureRecoveryFailure-rl6”. The RA information may be sent, for example, in a RA-InformationCommon information element (IE).

Although this information can be useful for MRO, it significantly increases the size of the SCGFailurelnformation message. Since this message is mandatory for the UE to send upon an SCG failure, it is desirable to keep the message size as small as possible to reduce UE energy consumption and network resource usage.

Additionally, some of the RA information may be redundant. When the UE is performing an SN change (e.g., after SCG failure), the UE always accesses the target SN via RA resources associated with the cell defining synchronization signal/PBCH block (SSB). Thus, the inclusion of the RA Information indicating the frequency resource information of the RA resources used to access the target SN, is redundant from that target SN’s point of view. Better ways to report RA information associated with an RLF or an HOF in the SCG are needed.

Accordingly, embodiments of the present disclosure provide flexible and efficient techniques to reduce the size of an SCGFailur eInformation message (or an equivalent message by which a UE inform the MN about an SN connection failure) when the UE declares SCG failure due to issues associated with a RA procedure. Some embodiments include techniques whereby a UE determines when to include only per-RA attempt information in the SCGFailur eInformation message. For example, the UE includes only the per-RA attempt information when:

• the SCG failure is declared due to a RA problem while performing RA in the default bandwidth part (BWP) or due to the expiry of T304 of SCG; or

• the SCG failure is declared either due to the SCG T304 expiry or due to the random access problem related issues in the target cell while T304 was running.

Other embodiments include techniques whereby a UE includes the (full) RA information:

• when the SCG failure is declared due to the RA related issues while performing RA in a BWP other than the default BWP; or

• only when the SCG failure is declared due to issues associated to RA procedure and while T304 is not running.

Other embodiments include combinations of the techniques summarized above, such as:

• the UE includes only the per RA attempt related information when the SCG failure is declared due to a RA problem while performing RA in the default bandwidth part or due to the expiry of T304 of SCG and the UE includes the RA information when the SCG failure is declared due to the RA problem related issues while performing RA in a BWP other than the default BWP; and

• the UE includes the RA information only when the SCG failure is declared due to issues associated with RA procedure and T304 is not running and the UE includes the per RA attempt related information when the SCG failure is declared due to issues associated to RA procedure while T304 is running or due to T304 expiry. In this manner, embodiments can reduce the size of the SCGFailur eInformation message by restricting when certain RA information available at the UE is included in this message. This improves the robustness of transmission of SCGFailur eInformation to the MN, reduces UE energy consumption, and reduces load on network resources. Even so, embodiments can provide similar advantages when used to reduce the size of MCGFailur eInformation messages sent by a UE.

In general, the term “per-RA attempt information” is used herein to refer to the contents of perRAInfoList IE defined in 3GPP TS 38.331 (vl6.7.0). Also, the term “RA information” is used herein to refer to the contents of the RA-InformationCommon-rl6 IE defined in 3GPP TS 38.331 (vl6.7.0), including both the frequency information of the RA resources and the per-RA attempt information. Figures 8A-B show exemplary ASN.l data structures for the RA- InformationCommon-rI6 IE and the perRAInfoList IE, respectively. Note that the perRAInfoList IE is part of the RA-InformationCommon-rl6 IE.

The following description refers to source nodes and target nodes, which in general are RAN nodes such as base stations. These RAN nodes can be LTE nodes (e.g., eNB or ng-eNB), NR nodes (e.g., gNB or en-gNB), or units of such nodes (e.g., CU or DU). Additionally, the following description is given in the context of the scenario wherein the UE declares SCG failure due to a RA-related reason. In such case, the UE sets the field failureType in the SCGFailur eInformation message to one of the following enumerated values: randomAccessProblem, synchReconfigfailureSCG, and beamFailureRecoveryFailure .

The following procedural text from 3GPP TS 38.331 (vl6.7.0) sections 5.7.3.4 and 5.7.3.5 captures these operations, in the context of an SCG Failure Information procedure by the UE. *** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measld configured and measurement results are available:

2> include an entry in measResultPerMOList,'

2> if there is a measld configured with the MeasObjectNR and a reportConfig which has rsType set to ssb

3>set ssbFrequency to the value indicated by ssbFrequency as included in the MeasObjectNR,

2> if there is a measld configured with the MeasObjectNR and a reportConfig which has rsType set to csi-rs'.

3>set refFreqCSI-RS to the value indicated by refFreqCSI-RS as included in the associated measurement object; 2>if a serving cell is associated with the MeasObjectNR'.

3>set measResultServingCell to include the available quantities of the concerned cell and in accordance with the performance requirements in TS 38.133 [14];

2>set the measResultNeighCellList to include the best measured cells, ordered such that the best cell is listed first, and based on measurements collected up to the moment the UE detected the failure, and set its fields as follows;

3> ordering the cells with sorting as follows:

4>based on SS/PBCH block if SS/PBCH block measurement results are available and otherwise based on CSI-RS;

4>using RSRP if RSRP measurement results are available, otherwise using RSRQ if RSRQ measurement results are available, otherwise using SINR;

3>for each neighbour cell included:

4> include the optional fields that are available.

NOTE: The measured quantities are filtered by the L3 filter as configured in the mobility measurement configuration. The measurements are based on the time domain measurement resource restriction, if configured. Blacklisted cells are not required to be reported.

2>if available, set the locationinfo as in 5.3.3.7.:

The UE shall set the contents of the SCGFailur eInfor mation message as follows:

1> if the UE initiates transmission of the SCGFailur eInformation message due to T310 expiry:

2> set the failureType as t310-Fxpiry l>else if the UE initiates transmission of the SCGFailur eInfor mation message to provide reconfiguration with sync failure information for an SCG: 2>set the failureType as synchReconfigFailureSCG,' l>else if the UE initiates transmission of the SCGFailur eInformation message to provide random access problem indication from SCG MAC:

2> if the random access procedure was initiated for beam failure recovery: 3>set the failureType as other and set the failureType-vl610 as beamFailureRecoveryFailure:

2> else:

3>set the failureTyp as randomAccessProblem

*** End 3GPP text *** Figure 9 shows an exemplary ASN. l data structure for an SCGFailur eInfor mation message, including the failureType field mentioned above. Embodiments will now be described in more detail using this existing procedural text and ASN.l data structure as baselines.

In some embodiments, the UE includes its available per-RA attempt information in the SCGFailur eInformation under any of the following conditions:

• when the UE sets failureType to synchReconfigFailureSCG,'

• when the UE sets failureType to randomAccessProblem and the associated RA resources were the same as the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIBy, and/or

• when the UE sets failureType to beamFailureRecoveryFailure and the associated RA resources were the same as the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB).

An advantage or benefit of these embodiments is that the size of the SCGFailur eInformation is kept small by not including available frequency information associated with the RA resources used in the RA procedure. Additionally, these embodiments ensure that the network can implicit derive that T304 was running at the UE at the time of declaring SCG failure, since the UE has included only perRAInfoList in the RA report. By not including available frequency-related information of the RA resources, the UE implicitly indicates to the network node that it performed the RA procedure in the default BWP.

The following procedural text that can be part of 3GPP TS 38.331 illustrates one example of these embodiments. Note that existing procedural text not affected by these embodiments is omitted, as indicated by ellipses.

*** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measIdG configured and measurement results are available:

2> include an entry in measResultPerMOList

2> if the UE initiates transmission of the SCGFailur elnformationNR message to provide reconfiguration with sync failure information for an SCG, or

2> if the UE initiates transmission of the SCGFailur elnformationNR message to provide random access problem indication from SCG MAC and if the random access resources associated to the RA procedure were the same as the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB): 3> set perRAInfoList to indicate the performed random access procedure related information as specified in 5.7.10.5;

*** End 3GPP text ***

The following procedural text that can be part of 3GPP TS 38.331 illustrates another example of these embodiments. Note that existing procedural text not affected by these embodiments is omitted, as indicated by ellipses.

*** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measIdG configured and measurement results are available:

2> include an entry in measResultPerMOList

2>set the failureType to the trigger for detecting SCG failure in accordance with clause 5.7.3.3;

2> if the failureType is set to synchReconfigFailureSCG, or

2> if the failureType is set to randomAccessProblem and if the random access resources associated to the RA procedure were the same as the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB), or

2> if the failureType is set to beamFailureRecoveryFailure and if the random access resources associated to the RA procedure were the same as the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB):

3> set perRAInfoList to indicate the performed random access procedure related information as specified in 5.7.10.5;

*** End 3GPP text ***

Figure 10 shows an exemplary ASN. l data structure for an SCGFailur eInformation message, according to these embodiments. This data structure includes two optional IES, perRAInfoList-r!6 and perRAInfoList-v!7, which can be included conditionally in accordance with either of the above examples of procedural text.

Note that the measResultFreqList field contains available results of measurements on NR frequencies the UE is configured to measure by measConfig. Additionally, the measResultSCG- Failure field contains a MeasResultSCG-Failure IE, which includes available results of measurements on NR frequencies the UE is configured to measure by the NR SCG RRCReconfiguration message. These fields are also present in other exemplary ASN.l data structures discussed below.

In other embodiments, the UE includes its available RA information in the SCGFailur eInformation when the UE performs a failed RA procedure in a BWP other than the default BWP. In this case, the RA resources used in the RA procedures are different from the ones provided in servingCellConfigCommon or servingCellConfigCommonSIB . The following procedural text that can be part of 3GPP TS 38.331 illustrates one example of these embodiments. Note that existing procedural text not affected by these embodiments is omitted, as indicated by ellipses.

*** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measldG configured and measurement results are available:

2> include an entry in measResultPerMOList

2> if the UE initiates transmission of the SCGFailur elnformationNR message to provide random access problem indication from SCG MAC and if the random access resources associated to the RA procedure were different from the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB):

3> set the ra-InformationCommon as specified in subclause 5.7.10.5;

*** End 3GPP text ***

The following procedural text that can be part of 3GPP TS 38.331 illustrates another example of these embodiments. Note that existing procedural text not affected by these embodiments is omitted, as indicated by ellipses.

*** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measIdG configured and measurement results are available:

2> include an entry in measResultPerMOList

2> set the failureType to the trigger for detecting SCG failure in accordance with clause 5.7.3.3; 2> if the failureType is set to beamFailureRecoveryFailure and if the random access resources associated to the RA procedure were different from the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB), or

2> if the failureType is set to randomAccessProblem and if the random access resources associated to the RA procedure were different from the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB):

3> set the ra-InformationCommon as specified in subclause 5.7.10.5;

*** End 3GPP text ***

Figure 11 shows an exemplary ASN. l data structure for an SCGFailur eInformation message, according to these embodiments. This data structure includes an optional IE, ra- InformationCommon-rl7, that can be included conditionally in accordance with either of the above examples of procedural text.

In other embodiments, the UE can include its available per-RA attempt information in the SCGFailur eInformation under any of the conditions mentioned in the first explanation of embodiments, and can include its available RA information in the SCGFailur eInformation under any of the conditions mentioned in the second explanation of embodiments. In other words, these embodiments can be viewed as a combination of the embodiments explained above.

The following procedural text that can be part of 3GPP TS 38.331 illustrates one example of these embodiments. Note that existing procedural text not affected by these embodiments is omitted, as indicated by ellipses.

*** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measIdG configured and measurement results are available:

2> include an entry in measResultPerMOList

2> if the UE initiates transmission of the SCGFailur elnformationNR message to provide reconfiguration with sync failure information for an SCG, or

2> if the UE initiates transmission of the SCGFailur elnformationNR message to provide random access problem indication from SCG MAC and if the random access resources associated to the RA procedure were the same as the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB):

3> set perRAInfoList to indicate the performed random access procedure related information as specified in 5.7.10.5;

2>else if the UE initiates transmission of the SCGFailurelnformationNR message to provide random access problem indication from SCG MAC and if the random access resources associated to the RA procedure were different from the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB):

3> set the ra-InformationCommon as specified in subclause 5.7.10.5;

2>set the measResultNeighCellList to include the best measured cells, ordered such that the best cell

*** End 3GPP text ***

The following procedural text that can be part of 3GPP TS 38.331 illustrates another example of these embodiments. Note that existing procedural text not affected by these embodiments is omitted, as indicated by ellipses.

*** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measldG configured and measurement results are available:

2> include an entry in measResultPerMOList

2>set the failureType to the trigger for detecting SCG failure in accordance with clause 5.7.3.3;

2> if the failureType is set to synchReconfigFailureSCG, or

2> if the failureType is set to randomAccessProblem and if the random access resources associated to the RA procedure were the same as the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB), or

2> if the failureType is set to beamFailureRecoveryFailure and if the random access resources associated to the RA procedure were the same as the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB): 3> set perRAInfoList to indicate the performed random access procedure related information as specified in 5.7.10.5;

2> if the failureType is set to beamFailureRecoveryFailure and if the random access resources associated to the RA procedure were different from the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB), or

2> if the failureType is set to randomAccessProblem and if the random access resources associated to the RA procedure were different from the ones provided in the default BWP (ones provided in servingCellConfigCommon or servingCellConfigCommonSIB):

3> set the ra-InformationCommon as specified in subclause 5.7.10.5;

*** End 3GPP text ***

Figure 12 shows an exemplary ASN. l data structure for an SCGFailur eInformation message, according to these embodiments. This data structure includes three optional IES, perRAInfoList-r!6, perRAInfoList-v!7, and ra-InformationCommon-r 17, which can be included conditionally in accordance with either of the above examples of procedural text.

Some embodiments described below relate to a more specific scenario involving an SCG change. In some embodiments, the UE includes its available per RA attempt information in the SCGFailurelnformation message under any of the following conditions:

• when the UE sets the failureType to synchReconfigFailureSCG,' or

• when the UE sets the failureType to randomAccessProblem and the SCG related T304 was running at the time of declaring SCG failure.

Like certain other embodiments discussed above, an advantage or benefit of these embodiments is that the size of the SCGFailurelnformation message is increased only when the UE is performing SCG change and fails in that procedure, instead of in all types of SCG failure scenarios associated with RA procedures. Even when the size of the SCGFailurelnformation message is increased when the UE fails in performing SCG change, only information not otherwise derivable by the network is included.

Additionally, these embodiments ensure that the network can implicitly derive that T304 was running at the UE at the time of declaring SCG failure, since the UE has included only perRAInfoList in the RA report. By not including available frequency -related information of the RA resources, the UE implicitly indicates to the network node that it performed the RA procedure in the default BWP. The following procedural text that can be part of 3GPP TS 38.331 illustrates one example of these embodiments. Note that existing procedural text not affected by these embodiments is omitted, as indicated by ellipses.

*** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measIdG configured and measurement results are available:

2> include an entry in measResultPerMOList

2> if the UE initiates transmission of the SCGFailurelnformationNR message to provide reconfiguration with sync failure information for an SCG, or

2> if the UE initiates transmission of the SCGFailurelnformationNR message to provide random access problem indication from SCG MAC and if the random access procedure was not initiated for beam failure recovery and if the T304 was running while the SCG failure was detected:

3> set perRAInfoList to indicate the performed random access procedure related information as specified in 5.7.10.5;

*** End 3GPP text ***

The following procedural text that can be part of 3GPP TS 38.331 illustrates another example of these embodiments. Note that existing procedural text not affected by these embodiments is omitted, as indicated by ellipses.

*** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measIdG configured and measurement results are available:

2> include an entry in measResultPerMOList

2> set the failureType to the trigger for detecting SCG failure in accordance with clause 5.7.3.3;

2> if the failureType is set to synchReconfigFailureSCG, or

2> if the failureType is set to randomAccessProblem and if the T304 was running while the SCG failure was detected:

3> set perRAInfoList to indicate the performed random access procedure related information as specified in 5.7.10.5; *** End 3GPP text ***

The exemplary ASN.l data structure shown in Figure 10 can be used in conjunction with either of the above examples of procedural text.

In other embodiments, the UE includes its available RA information in the SCGFailurelnformation message when the UE sets the failureType field to randomAccessProblem and the SCG-related T304 was not running at the time of declaring SCG failure. The following procedural text that can be part of 3GPP TS 38.331 illustrates one example of these embodiments. Note that existing procedural text not affected by these embodiments is omitted, as indicated by ellipses.

*** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measIdG configured and measurement results are available:

2> include an entry in measResultPerMOList

2> if the UE initiates transmission of the SCGFailurelnformationNR message to provide random access problem indication from SCG MAC and if the T304 was not running while the SCG failure was detected:

3> set the ra-InformationCommon as specified in subclause 5.7.10.5;

*** End 3GPP text ***

The following procedural text that can be part of 3GPP TS 38.331 illustrates another example of these embodiments. Note that existing procedural text not affected by these embodiments is omitted, as indicated by ellipses.

*** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measIdG configured and measurement results are available:

2> include an entry in measResultPerMOList

2> set the failureType to the trigger for detecting SCG failure in accordance with clause 5.7.3.3;

2> if the failureType is set to beamFailureRecoveryFailure and if the T304 was not running while the SCG failure was detected, or 2> if the failureType is set to randomAccessProblem and if the T304 was not running while the SCG failure was detected:

3> set the ra-InformationCommon as specified in subclause 5.7.10.5;

*** End 3GPP text ***

The exemplary ASN.1 data structure shown in Figure 11 can be used in conjunction with either of the above examples of procedural text.

In other embodiments, the UE can include its available per-RA attempt information and can include the RA information in the SCGFailur eInformation under any of the conditions mentioned above in the explanations of the respective embodiments. In other words, these embodiments can be viewed as a combination of the embodiments explained above, i.e., related to SCG change. The following procedural text that can be part of 3GPP TS 38.331 illustrates one example of these embodiments. Note that existing procedural text not affected by these embodiments is omitted, as indicated by ellipses.

*** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measldG configured and measurement results are available:

2> include an entry in measResultPerMOList

2> if the UE initiates transmission of the SCGFailur elnformationNR message to provide random access problem indication from SCG MAC and if the T304 was not running while the SCG failure was detected:

3> set the ra-InformationCommon as specified in subclause 5.7.10.5;

2> else

3> if the UE initiates transmission of the SCGFailurelnformationNR message to provide reconfiguration with sync failure information for an SCG, or

3> if the UE initiates transmission of the SCGFailurelnformationNR message to provide random access problem indication from SCG MAC and if the random access procedure was not initiated for beam failure recovery and if the T304 was running while the SCG failure was detected:

4> set perRAInfoList to indicate the performed random access procedure related information as specified in 5.7.10.5;

*** End 3GPP text *** The following procedural text that can be part of 3GPP TS 38.331 illustrates another example of these embodiments. Note that existing procedural text not affected by these embodiments is omitted, as indicated by ellipses.

*** Begin 3 GPP text ***

The UE shall set the contents of the MeasResultSCG-Failure as follows: l>for each MeasObjectNR configured on NR SCG for which a measIdG configured and measurement results are available:

2> include an entry in measResultPerMOList

2> set the failureType to the trigger for detecting SCG failure in accordance with clause 5.7.3.3;

2> if the failureType is set to beamFailureRecoveryFailure, or

2> if the failureType is set to randomAccessProblem and if the T304 was not running while the SCG failure was detected:

3> set the ra-InformationCommon as specified in subclause 5.7.10.5;

2> if the failureType is set to synchReconfigFailureSCG, or

2> if the failureType is set to randomAccessProblem and if the T304 was running while the SCG failure was detected:

3> set perRAInfoList to indicate the performed random access procedure related information as specified in 5.7.10.5;

*** End 3GPP text ***

The exemplary ASN.l data structure shown in Figure 12 can be used in conjunction with either of the above examples of procedural text.

Various features of the embodiments described above correspond to various operations illustrated in Figures 13-14, which show exemplary methods (e.g., procedures) for a UE and a RAN node, respectively. In other words, various features of the operations described below correspond to various embodiments described above. Furthermore, the exemplary methods shown in Figures 13-14 can be used cooperatively to provide various benefits, advantages, and/or solutions to problems described herein. Although Figures 13-14 show specific blocks in particular orders, the operations of the exemplary methods can be performed in different orders than shown and can be combined and/or divided into blocks having different functionality than shown. Optional blocks or operations are indicated by dashed lines.

In particular, Figure 13 shows an exemplary method (e.g., procedure) for a UE configured with an MCG and an SCG in a RAN, according to various embodiments of the present disclosure. The exemplary method can be performed by a UE e.g., wireless device, etc.) such as described elsewhere herein.

The exemplary method can include the operations of block 1310, where the UE can detect a failure of the SCG. The exemplary method can also include the operations of block 1320, where the UE can determine whether the SCG failure is any one of a plurality of predetermined failure types. The exemplary method can also include the operations of block 1330, where the UE can selectively include available RA information in an SCG failure information report based on determining that the SCG failure is one of the predetermined failure types. The exemplary method can also include the operations of block 1340, where the UE can send the SCG failure information report to a RAN node (e.g., the RAN node that provides the UE’s MCG).

In some embodiments, selectively including RA information in block 1330 can include the operations of block 1331, where the UE can include a subset of the available RA information in the SCG failure report based on which one of the predetermined failure types is associated with the SCG failure.

In some of these embodiments, the subset of the available RA information is included in the SCG failure report based on determining (e.g., in block 1330) that the SCG failure is reconfiguration with sync failure in the SCG. In some of these embodiments, the subset of the available RA information is included in the SCG failure report based on determining (e.g., in block 1330) that the SCG failure is a RA problem indicated by the UE’s medium access control (MAC) entity associated with the SCG and that a timer (T304) associated with the SCG was running when the SCG failure was detected.

In some of these embodiments, the subset of the available RA information is included in the SCG failure report based on determining (e.g., in block 1330) that the SCG failure is one of the following failure types:

• a reconfiguration with sync failure; or

• a RA problem or a failed recovery, and the SCG failure occurred in a default BWP associated with the SCG.

In some embodiments, the available RA information includes per-RA attempt information and frequency-related information, and the subset of the available RA information includes the includes per-RA attempt information. The subset may exclude the frequency-related information. In some of these embodiments, when included in the SCG failure information report, the subset is contained in a perRAInfoList IE. Figures 10 and 12 show some examples of these embodiments.

In some embodiments, the SCG failure information report indicates which one of the predetermined failure types is associated with the SCG failure. An example of this indication is the failureType field discussed above. In some of these embodiments, the plurality of predetermined failure types include a reconfiguration with sync failure in the SCG. In some of these embodiments, the plurality of predetermined failure types include a RA problem indicated by the UE’s MAC entity associated with the SCG. In some of these embodiments, the plurality of predetermined failure types include a failed recovery from a beam failure associated with the SCG.

In some embodiments, selectively including RA information in block 1330 can include the operations of block 1332, where the UE can include all of the available RA information in the SCG failure information report when the following applies: the SCG failure is a RA problem or a failed recovery, and the SCG failure occurred in a BWP other than a default BWP associated with the SCG. Note that the operations of sub-blocks 1331-1332 are not exclusive of each other.

In some embodiments, selectively including RA information in block 1330 can include the operations of block 1333, where the UE can include all of the available RA information in the SCG failure information report when the following applies: the SCG failure is a RA problem or a failed recovery, and a timer (T304) associated with the SCG was not running when the SCG failure was detected. Note that the operations of sub-blocks 1331-1333 are not exclusive of each other.

In addition, Figure 14 shows an exemplary method (e.g., procedure) for a RAN node configured to provide an MCG for a UE that is also configured with an SCG in the RAN, according to various embodiments of the present disclosure. The exemplary method can be performed by a RAN node (e.g., base station, eNB, gNB, ng-eNB, TRP, etc. such as described elsewhere herein.

The exemplary method can include the operations of block 1410, where the RAN node can receive from the UE an SCG failure information report related to a failure detected by the UE in the SCG. The SCG failure information report selectively includes a subset of RA information available at the UE, based on which one of a plurality of predetermined failure types is associated with the SCG failure. This SCG failure information report can correspond to the one described above in relation to Figure 13.

In some embodiments, the SCG failure information report includes the subset of the available RA information when the SCG failure is a reconfiguration with sync failure. In some embodiments, the SCG failure information report includes the subset of the available RA information when the SCG failure is a RA problem indicated by the UE’s MAC entity associated with the SCG and a UE timer (T304) associated with the SCG was running when the SCG failure was detected.

In some embodiments, the SCG failure information report includes the subset of the available RA information when one of the following applies:

• the SCG failure is a reconfiguration with sync failure; or

• the SCG failure is a RA problem or a failed recovery, and the failure occurred in a default BWP associated with the SCG. In some embodiments, the available RA information includes per-RA attempt information and frequency-related information, and the subset of the available RA information includes the includes per-RA attempt information. The subset may exclude the frequency-related information. In some of these embodiments, when included in the SCG failure information report, the subset of the available RA information is contained in a perRAInfoList IE. Figures 10 and 12 show some examples of these embodiments.

In some embodiments, the SCG failure information report indicates which one of the predetermined failure types is associated with the SCG failure. An example of this indication is the failureType field discussed above.

In some embodiments the SCG failure information report includes all of the available RA information when the following applies: the SCG failure is a RA problem or a failed recovery, and the SCG failure occurred in a BWP other than a default BWP associated with the SCG.

In some embodiments, the SCG failure information report includes all of the available RA information when the following applies: the SCG failure is a RA problem or a failed recovery, and a timer (T304) associated with the SCG was not running when the SCG failure was detected.

In some embodiments, the plurality of predetermined failure types include a reconfiguration with sync failure in the SCG. In some embodiments, the plurality of predetermined failure types include a RA problem indicated by the UE’s MAC entity associated with the SCG. In some embodiments, the plurality of predetermined failure types include a failed recovery from a beam failure associated with the SCG.

In some embodiments, the exemplary method can also include the operations of block 1420, where the RAN node can determine whether the UE performed a RA procedure in a default BWP of the SCG based on whether the subset of the available RA information is included in the SCG failure information report.

Although various embodiments are described above in terms of methods, techniques, and/or procedures, the person of ordinary skill will readily comprehend that such methods, techniques, and/or procedures can be embodied by various combinations of hardware and software in various systems, communication devices, computing devices, control devices, apparatuses, non-transitory computer-readable media, computer program products, etc.

Figure 15 shows an example of a communication system 1500 in accordance with some embodiments. In this example, communication system 1500 includes a telecommunication network 1502 that includes an access network 1504, such as a RAN, and a core network 1506, which includes one or more core network nodes 1508. Access network 1504 includes one or more access network nodes, such as network nodes 1510a-b (one or more of which may be generally referred to as network nodes 1510), or any other similar 3 GPP access node or non-3GPP access point. Network nodes 1510 facilitate direct or indirect connection of UEs, such as by connecting UEs 1512a-d (one or more of which may be generally referred to as UEs 1512) to core network 1506 over one or more wireless connections.

Example wireless communications over a wireless connection include transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, communication system 1500 may include any number of wired or wireless networks, network nodes, UEs, and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections. Communication system 1500 may include and/or interface with any type of communication, telecommunication, data, cellular, radio network, and/or other similar type of system.

UEs 1512 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and/or operable to communicate wirelessly with network nodes 1510 and other communication devices. Similarly, network nodes 1510 are arranged, capable, configured, and/or operable to communicate directly or indirectly with UEs 1512 and/or with other network nodes or equipment in telecommunication network 1502 to enable and/or provide network access, such as wireless network access, and/or to perform other functions, such as administration in telecommunication network 1502.

In the depicted example, core network 1506 connects network nodes 1510 to one or more hosts, such as host 1516. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. Core network 1506 includes one more core network nodes (e.g., core network node 1508) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and/or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 1508. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and/or a User Plane Function (UPF).

Host 1516 may be under the ownership or control of a service provider other than an operator or provider of access network 1504 and/or telecommunication network 1502, and may be operated by the service provider or on behalf of the service provider. Host 1516 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio/video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

As a whole, communication system 1500 of Figure 15 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and/or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and/or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

In some examples, telecommunication network 1502 is a cellular network that implements 3GPP standardized features. Accordingly, telecommunication network 1502 may support network slicing to provide different logical networks to different devices that are connected to telecommunication network 1502. For example, telecommunication network 1502 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and/or Massive Machine Type Communication (mMTC)/Massive loT services to yet further UEs.

In some examples, UEs 1512 are configured to transmit and/or receive information without direct human interaction. For instance, a UE may be designed to transmit information to access network 1504 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from access network 1504. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e., being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

In the example, hub 1514 communicates with access network 1504 to facilitate indirect communication between one or more UEs (e.g., UE 1512c and/or 1512d) and network nodes (e.g., network node 1510b). In some examples, hub 1514 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, hub 1514 may be a broadband router enabling access to core network 1506 for the UEs. As another example, hub 1514 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 1510, or by executable code, script, process, or other instructions in hub 1514. As another example, hub 1514 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, hub 1514 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, hub 1514 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which hub 1514 then provides to the UE either directly, after performing local processing, and/or after adding additional local content. In still another example, hub 1514 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.

Hub 1514 may have a constant/persistent or intermittent connection to the network node 1510b. Hub 1514 may also allow for a different communication scheme and/or schedule between hub 1514 and UEs (e.g., UE 1512c and/or 1512d), and between hub 1514 and core network 1506. In other examples, hub 1514 is connected to core network 1506 and/or one or more UEs via a wired connection. Moreover, hub 1514 may be configured to connect to an M2M service provider over access network 1504 and/or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with network nodes 1510 while still connected via hub 1514 via a wired or wireless connection. In some embodiments, hub 1514 may be a dedicated hub - that is, a hub whose primary function is to route communications to/from the UEs from/to the network node 1510b. In other embodiments, hub 1514 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 1510b, but which is additionally capable of operating as a communication start and/or end point for certain data channels.

Figure 16 shows a UE 1600 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded/integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3 GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE.

A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and/or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

UE 1600 includes processing circuitry 1602 that is operatively coupled via a bus 1604 to an input/output interface 1606, a power source 1608, a memory 1610, a communication interface 1612, and/or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 16. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

Processing circuitry 1602 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in memory 1610. Processing circuitry 1602 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field- programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general -purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, processing circuitry 1602 may include multiple central processing units (CPUs).

In the example, input/output interface 1606 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and/or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into UE 1600. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

In some embodiments, power source 1608 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. Power source 1608 may further include power circuitry for delivering power from power source 1608 itself, and/or an external power source, to the various parts of UE 1600 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of power source 1608. Power circuitry may perform any formatting, converting, or other modification to the power from power source 1608 to make the power suitable for the respective components of UE 1600 to which power is supplied.

Memory 1610 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, memory 1610 includes one or more application programs 1614, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1616. Memory 1610 may store, for use by UE 1600, any of a variety of various operating systems or combinations of operating systems.

Memory 1610 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and/or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ Memory 1610 may allow UE 1600 to access instructions, application programs and the like, stored on transitory or non- transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in memory 1610, which may be or comprise a device-readable storage medium. Processing circuitry 1602 may be configured to communicate with an access network or other network using communication interface 1612. Communication interface 1612 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 1622. Communication interface 1612 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 1618 and/or a receiver 1620 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, transmitter 1618 and receiver 1620 may be coupled to one or more antennas (e.g., antenna 1622) and may share circuit components, software or firmware, or alternatively be implemented separately.

In the illustrated embodiment, communication functions of communication interface 1612 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and/or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol/internet protocol (TCP/IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 1612, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., an alert is sent when moisture is detected), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input. A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door/window sensor, a flood/moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and/or software in dependence of the intended application of the loT device in addition to other components as described in relation to UE 1600 shown in Figure 16.

As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another UE and/or a network node. The UE may in this case be an M2M device, which may in a 3 GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3 GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation.

In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the drone’s speed. The first and/or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

Figure 17 shows a network node 1700 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and/or operable to communicate directly or indirectly with a UE and/or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NRNodeBs (gNBs)).

Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and/or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell/multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and/or Minimization of Drive Tests (MDTs).

Network node 1700 includes a processing circuitry 1702, a memory 1704, a communication interface 1706, and a power source 1708. Network node 1700 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which network node 1700 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, network node 1700 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1704 for different RATs) and some components may be reused (e.g., a same antenna 1710 may be shared by different RATs). Network node 1700 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1700, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z- wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1700.

Processing circuitry 1702 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and/or encoded logic operable to provide, either alone or in conjunction with other network node 1700 components, such as memory 1704, to provide network node 1700 functionality.

In some embodiments, processing circuitry 1702 includes a system on a chip (SOC). In some embodiments, processing circuitry 1702 includes one or more of radio frequency (RF) transceiver circuitry 1712 and baseband processing circuitry 1714. In some embodiments, RF transceiver circuitry 1712 and baseband processing circuitry 1714 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 1712 and baseband processing circuitry 1714 may be on the same chip or set of chips, boards, or units.

Memory 1704 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device-readable and/or computer-executable memory devices that store information, data, and/or instructions that may be used by processing circuitry 1702. Memory 1704 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and/or other instructions (collectively denoted computer program product 1704a) capable of being executed by processing circuitry 1702 and utilized by network node 1700. Memory 1704 may be used to store any calculations made by processing circuitry 1702 and/or any data received via communication interface 1706. In some embodiments, processing circuitry 1702 and memory 1704 is integrated.

Communication interface 1706 is used in wired or wireless communication of signaling and/or data between a network node, access network, and/or UE. As illustrated, communication interface 1706 comprises port(s)/terminal(s) 1716 to send and receive data, for example to and from a network over a wired connection. Communication interface 1706 also includes radio frontend circuitry 1718 that may be coupled to, or in certain embodiments a part of, antenna 1710. Radio front-end circuitry 1718 comprises filters 1720 and amplifiers 1722. Radio front-end circuitry 1718 may be connected to an antenna 1710 and processing circuitry 1702. The radio front-end circuitry may be configured to condition signals communicated between antenna 1710 and processing circuitry 1702. Radio front-end circuitry 1718 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. Radio front-end circuitry 1718 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1720 and/or amplifiers 1722. The radio signal may then be transmitted via antenna 1710. Similarly, when receiving data, antenna 1710 may collect radio signals which are then converted into digital data by radio front-end circuitry 1718. The digital data may be passed to processing circuitry 1702. In other embodiments, the communication interface may comprise different components and/or different combinations of components.

In certain alternative embodiments, network node 1700 does not include separate radio front-end circuitry 1718, instead, processing circuitry 1702 includes radio front-end circuitry and is connected to antenna 1710. Similarly, in some embodiments, all or some of RF transceiver circuitry 1712 is part of communication interface 1706. In still other embodiments, communication interface 1706 includes one or more ports or terminals 1716, radio front-end circuitry 1718, and RF transceiver circuitry 1712, as part of a radio unit (not shown), and communication interface 1706 communicates with baseband processing circuitry 1714, which is part of a digital unit (not shown).

Antenna 1710 may include one or more antennas, or antenna arrays, configured to send and/or receive wireless signals. Antenna 1710 may be coupled to radio front-end circuitry 1718 and may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In certain embodiments, antenna 1710 is separate from network node 1700 and connectable to network node 1700 through an interface or port.

Antenna 1710, communication interface 1706, and/or processing circuitry 1702 may be configured to perform any receiving operations and/or certain obtaining operations described herein as being performed by the network node. Any information, data and/or signals may be received from a UE, another network node and/or any other network equipment. Similarly, antenna 1710, communication interface 1706, and/or processing circuitry 1702 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and/or signals may be transmitted to a UE, another network node and/or any other network equipment.

Power source 1708 provides power to the various components of network node 1700 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). Power source 1708 may further comprise, or be coupled to, power management circuitry to supply the components of network node 1700 with power for performing the functionality described herein. For example, network node 1700 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of power source 1708. As a further example, power source 1708 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

Embodiments of network node 1700 may include additional components beyond those shown in Figure 17 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and/or any functionality necessary to support the subject matter described herein. For example, network node 1700 may include user interface equipment to allow input of information into network node 1700 and to allow output of information from network node 1700. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for network node 1700.

Figure 18 is a block diagram of a host 1800, which may be an embodiment of host 1516 of Figure 15, in accordance with various aspects described herein. As used herein, host 1800 may be or comprise various combinations hardware and/or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. Host 1800 may provide one or more services to one or more UEs.

Host 1800 includes processing circuitry 1802 that is operatively coupled via a bus 1804 to an input/output interface 1806, a network interface 1808, a power source 1810, and a memory 1812. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 16 and 17, such that the descriptions thereof are generally applicable to the corresponding components of host 1800.

Memory 1812 may include one or more computer programs including one or more host application programs 1814 and data 1816, which may include user data, e.g., data generated by a UE for host 1800 or data generated by host 1800 for a UE. Embodiments of host 1800 may utilize only a subset or all of the components shown. Host application programs 1814 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FLAC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems). Host application programs 1814 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, host 1800 may select and/or indicate a different host for over-the-top services for a UE. Host application programs 1814 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real- Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.

Figure 19 is a block diagram illustrating a virtualization environment 1900 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1900 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized.

Applications 1902 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 1900 to implement some of the features, functions, and/or benefits of some of the embodiments disclosed herein.

Hardware 1904 includes processing circuitry, memory that stores software and/or instructions (collectively denoted computer program product 1904a) executable by hardware processing circuitry, and/or other hardware devices as described herein, such as a network interface, input/output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1906 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1908a and 1908b (one or more of which may be generally referred to as VMs 1908), and/or perform any of the functions, features and/or benefits described in relation with some embodiments described herein. The virtualization layer 1906 may present a virtual operating platform that appears like networking hardware to the VMs 1908.

VMs 1908 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1906. Different embodiments of the instance of a virtual appliance 1902 may be implemented on one or more of VMs 1908, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

In the context of NFV, a VM 1908 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of VMs 1908, and that part of hardware 1904 that executes that VM, be it hardware dedicated to that VM and/or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1908 on top of hardware 1904 and corresponds to application 1902.

Hardware 1904 may be implemented in a standalone network node with generic or specific components. Hardware 1904 may implement some functions via virtualization. Alternatively, hardware 1904 may be part of a larger cluster of hardware (e.g., such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1910, which, among others, oversees lifecycle management of applications 1902. In some embodiments, hardware 1904 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1912 which may alternatively be used for communication between hardware nodes and radio units.

Figure 20 shows a communication diagram of a host 2002 communicating via a network node 2004 with a UE 2006 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as a UE 1512a of Figure 15 and/or UE 1600 of Figure 16), network node (such as network node 1510a of Figure 15 and/or network node 1700 of Figure 17), and host (such as host 1516 of Figure 15 and/or host 1800 of Figure 18) discussed in the preceding paragraphs will now be described with reference to Figure 20.

Like host 1800, embodiments of host 2002 include hardware, such as a communication interface, processing circuitry, and memory. Host 2002 also includes software, which is stored in or accessible by host 2002 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as UE 2006 connecting via an over-the-top (OTT) connection 2050 extending between UE 2006 and host 2002. In providing the service to the remote user, a host application may provide user data which is transmitted using OTT connection 2050.

Network node 2004 includes hardware enabling it to communicate with host 2002 and UE 2006. Connection 2060 may be direct or pass through a core network (like core network 1506 of Figure 15) and/or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.

UE 2006 includes hardware and software, which is stored in or accessible by UE 2006 and executable by the UE’s processing circuitry. The software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via UE 2006 with the support of host 2002. In host 2002, an executing host application may communicate with the executing client application via OTT connection 2050 terminating at UE 2006 and host 2002. In providing the service to the user, the UE's client application may receive request data from the host's host application and provide user data in response to the request data. OTT connection 2050 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through OTT connection 2050.

OTT connection 2050 may extend via a connection 2060 between host 2002 and network node 2004 and via a wireless connection 2070 between network node 2004 and UE 2006 to provide the connection between host 2002 and UE 2006. Connection 2060 and wireless connection 2070, over which OTT connection 2050 may be provided, have been drawn abstractly to illustrate the communication between host 2002 and UE 2006 via network node 2004, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

As an example of transmitting data via OTT connection 2050, in step 2008, host 2002 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with UE 2006. In other embodiments, the user data is associated with a UE 2006 that shares data with host 2002 without explicit human interaction. In step 2010, host 2002 initiates a transmission carrying the user data towards UE 2006. Host 2002 may initiate the transmission responsive to a request transmitted by UE 2006. The request may be caused by human interaction with UE 2006 or by operation of the client application executing on UE 2006. The transmission may pass via network node 2004, in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step 2012, network node 2004 transmits to UE 2006 the user data that was carried in the transmission that host 2002 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 2014, UE 2006 receives the user data carried in the transmission, which may be performed by a client application executed on UE 2006 associated with the host application executed by host 2002.

In some examples, UE 2006 executes a client application which provides user data to host 2002. The user data may be provided in reaction or response to the data received from host 2002. Accordingly, in step 2016, UE 2006 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input/output interface of UE 2006. Regardless of the specific manner in which the user data was provided, UE 2006 initiates, in step 2018, transmission of the user data towards host 2002 via network node 2004. In step 2020, in accordance with the teachings of the embodiments described throughout this disclosure, network node 2004 receives user data from UE 2006 and initiates transmission of the received user data towards host 2002. In step 2022, host 2002 receives the user data carried in the transmission initiated by UE 2006.

One or more of the various embodiments improve the performance of OTT services provided to UE 2006 using OTT connection 2050, in which the wireless connection 2070 forms the last segment. More precisely, embodiments described herein can reduce the size of an SCGFailur eInformation message by restricting when certain RA information is included in the message. This improves the robustness of transmission of SCGFailur eInformation to the MN, reduces UE energy consumption, and reduces load on network resources. Embodiments can provide similar advantages when used to reduce the size of MCGFailur eInformation messages sent by a UE. At a high level, embodiments improve mobility robustness for UEs operating in the network. When networks and UEs improved in this manner are used to deliver OTT services, they increase the value of such services to end users and service providers.

In an example scenario, factory status information may be collected and analyzed by host 2002. As another example, host 2002 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, host 2002 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, host 2002 may store surveillance video uploaded by a UE. As another example, host 2002 may store or control access to media content such as video, audio, VR or AR which it can broadcast, multicast or unicast to UEs. As other examples, host 2002 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing and/or transmitting data. In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring OTT connection 2050 between host 2002 and UE 2006, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection may be implemented in software and hardware of host 2002 and/or UE 2006. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which OTT connection 2050 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of OTT connection 2050 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of network node 2004. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency and the like, by host 2002. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using OTT connection 2050 while monitoring propagation times, errors, etc.

The foregoing merely illustrates the principles of the disclosure. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements, and procedures that, although not explicitly shown or described herein, embody the principles of the disclosure and can be thus within the spirit and scope of the disclosure. Various embodiments can be used together with one another, as well as interchangeably therewith, as should be understood by those having ordinary skill in the art.

The term unit, as used herein, can have conventional meaning in the field of electronics, electrical devices and/or electronic devices and can include, for example, electrical and/or electronic circuitry, devices, modules, processors, memories, logic solid state and/or discrete devices, computer programs or instructions for carrying out respective tasks, procedures, computations, outputs, and/or displaying functions, and so on, as such as those that are described herein.

Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.

As described herein, device and/or apparatus can be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of a device or apparatus, instead of being hardware implemented, be implemented as a software module such as a computer program or a computer program product comprising executable software code portions for execution or being run on a processor. Furthermore, functionality of a device or apparatus can be implemented by any combination of hardware and software. A device or apparatus can also be regarded as an assembly of multiple devices and/or apparatuses, whether functionally in cooperation with or independently of each other. Moreover, devices and apparatuses can be implemented in a distributed fashion throughout a system, so long as the functionality of the device or apparatus is preserved. Such and similar principles are considered as known to a skilled person.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In addition, certain terms used in the present disclosure, including the specification and drawings, can be used synonymously in certain instances (e.g., “data” and “information”). It should be understood, that although these terms (and/or other terms that can be synonymous to one another) can be used synonymously herein, there can be instances when such words can be intended to not be used synonymously. Further, to the extent that the prior art knowledge has not been explicitly incorporated by reference herein above, it is explicitly incorporated herein in its entirety. All publications referenced are incorporated herein by reference in their entireties.

Embodiments of the techniques and apparatus described herein also include, but are not limited to, the following enumerated examples: Al . A method for a user equipment (UE) configured with a master cell group (MCG) and a secondary cell group (SCG) in a radio access network (RAN), the method comprising: detecting a failure of the SCG; determining whether the SCG failure is any one of a plurality of predetermined failure types; and selectively including random access (RA) information in an SCG failure information report based on determining that the SCG failure is one of the predetermined failure types; and sending the SCG failure information report to a RAN node.

A2. The method of embodiment Al, wherein the SCG failure information report indicates which one of the predetermined failure types is associated with the SCG failure.

A3. The method of any of embodiments A1-A2, wherein the plurality of predetermined failure types include the following: a reconfiguration with sync failure in the SCG; a RA problem indicated by the UE’s medium access control (MAC) entity associated with the SCG; and a failed recovery from a beam failure associated with the SCG.

A4. The method of embodiment A3, wherein selectively including RA information comprises including a subset of the RA information in the SCG failure information report when one of the following applies: the failure is a reconfiguration with sync failure; or the failure is a RA problem or a failed recovery, and the failure occurred in a default bandwidth part (BWP) associated with the SCG.

A5. The method of any of embodiments A3-A4, wherein selectively including RA information comprises including all of the RA information in the SCG failure information report when the following applies: the failure is a RA problem or a failed recovery, and the failure occurred in a bandwidth part (BWP) other than a default BWP associated with the SCG. A6. The method of any of embodiment A3, wherein selectively including RA information comprises including a subset of the RA information in the SCG failure information report when one of the following applies: the failure is a reconfiguration with sync failure; or the failure is a RA problem and a timer (T304) associated with the SCG was running when the failure was detected.

A7. The method of any of embodiments A3 or A6, wherein selectively including RA information comprises including all of the RA information in the SCG failure information report when the following applies: the failure is a RA problem or a failed recovery, and a timer (T304) associated with the SCG was not running when the failure was detected.

A8. The method of any of embodiments A4-A7, wherein: the RA information includes per-RA attempt information and frequency -related information; and the subset includes the includes per-RA attempt information but does not include the frequency-related information.

A9. The method of embodiment A8, wherein: the RA information is contained in an RA-InformationCommon information element (IE) that is selectively included in the SCG failure information report; and the subset is contained in a perRAInfoList IE that is selectively included in the SCG failure information report.

A10. The method of embodiments A1-A9, wherein the RAN node provides the UE’s MCG.

Bl. A method for a radio access network (RAN) node configured to provide a master cell group (MCG) for a user equipment (UE) that is also configured with a secondary cell group, (SCG) in the RAN, the method comprising: receiving, from the UE, an SCG failure information report related to a failure detected by the UE in the SCG, wherein the SCG failure information report selectively includes all or a subset of random access (RA) information based on whether the SCG failure is one of a plurality of predetermined failure types. B2. The method of embodiment Bl, wherein the SCG failure information report indicates which one of the predetermined failure types is associated with the SCG failure.

B3. The method of any of embodiments B1-B2, wherein the plurality of predetermined failure types include the following: a reconfiguration with sync failure in the SCG; a RA problem indicated by the UE’s medium access control (MAC) entity associated with the SCG; and a failed recovery from a beam failure associated with the SCG.

B4. The method of embodiment B3, wherein the SCG failure information report includes a subset of the RA information when one of the following applies: the failure is a reconfiguration with sync failure; or the failure is a RA problem or a failed recovery, and the failure occurred in a default bandwidth part (BWP) associated with the SCG.

B5. The method of any of embodiments B3-B4, wherein the SCG failure information report includes all of the RA information when the following applies: the failure is a RA problem or a failed recovery, and the failure occurred in a bandwidth part (BWP) other than a default BWP associated with the SCG.

B6. The method of any of embodiment B3, wherein the SCG failure information report includes a subset of the RA information when one of the following applies: the failure is a reconfiguration with sync failure; or the failure is a RA problem and a UE timer (T304) associated with the SCG was running when the failure was detected.

B7. The method of any of embodiments B3 or B6, wherein the SCG failure information report includes all of the RA information when the following applies: the failure is a RA problem or a failed recovery, and a UE timer (T304) associated with the SCG was not running when the failure was detected.

B8. The method of any of embodiments B4-B7, wherein: the RA information includes per-RA attempt information and frequency -related information; and the subset includes the includes per-RA attempt information but does not include the frequency-related information.

B9. The method of embodiment B8, wherein: the RA information is contained in an RA-InformationCommon information element (IE) that is selectively included in the SCG failure information report; and the subset is contained in a perRAInfoList IE that is selectively included in the SCG failure information report.

BIO. The method of any of embodiments B1-B9, further comprising determining whether the UE performed a RA procedure in a default bandwidth part (BWP) of the SCG based on whether all or a subset of the RA information is included in the SCG failure information report.

Cl . A user equipment (UE) configured with a master cell group (MCG) and a secondary cell group (SCG) in a radio access network (RAN), the UE comprising: communication interface circuitry configured to communicate with RAN nodes that provide the MCG and the SCG; and processing circuitry operatively coupled to the radio transceiver circuitry, whereby the processing circuitry and the radio transceiver circuitry are configured to perform operations corresponding to any of the methods of embodiments A1-A10.

C2. A user equipment (UE) configured with a master cell group (MCG) and a secondary cell group (SCG) in a radio access network (RAN), the UE being further configured to perform operations corresponding to any of the methods of embodiments A1-A10.

C3. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a user equipment (UE) configured with a master cell group (MCG) and a secondary cell group (SCG) in a radio access network (RAN), configure the UE to perform operations corresponding to any of the methods of embodiments A1-A10.

C4. A computer program product comprising computer-executable instructions that, when executed by processing circuitry of a user equipment (UE) configured with a master cell group (MCG) and a secondary cell group (SCG) in a radio access network (RAN), configure the UE to perform operations corresponding to any of the methods of embodiments A1-A10. DI . A radio access network (RAN) node configured to provide a master cell group (MCG) for a user equipment (UE) that is also configured with a secondary cell group (SCG) in the RAN, the RAN node comprising: communication interface circuitry configured to communicate with UEs; and processing circuitry operatively coupled to the communication interface circuitry, whereby the processing circuitry and the communication interface circuitry are configured to perform operations corresponding to any of the methods of embodiments Bl -BIO.

D2. A radio access network (RAN) node configured to provide a master cell group (MCG) for a user equipment (UE) that is also configured with a secondary cell group (SCG) in the RAN, the RAN node being further configured to perform operations corresponding to any of the methods of embodiments Bl -BIO.

D3. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a radio access network (RAN) node configured to provide a master cell group (MCG) for a user equipment (UE) that is also configured with a secondary cell group (SCG) in the RAN, configure the RAN node to perform operations corresponding to any of the methods of embodiments Bl -BIO.

D4. A computer program product comprising computer-executable instructions that, when executed by processing circuitry of a radio access network (RAN) node configured to provide a master cell group (MCG) for a user equipment (UE) that is also configured with a secondary cell group (SCG) in the RAN, configure the RAN node to perform operations corresponding to any of the methods of embodiments Bl -BIO.