TECHNICAL FIELD

[0001] The present disclosure relates to wireless communication networks, and in particular to systems and methods for performing conditional PSCell change.

BACKGROUND

[0002] In 3GPP Rel-12, the Long Term Evolution (LTE) feature of Dual Connectivity (DC) was introduced to enable the user equipment (UE) to be connected in two cell groups, each controlled by an LTE access node, eNodeBs (eNBs), labelled as the Master eNB, MeNB and the Secondary eNB, SeNB. The UE still only has one radio resource control (RRC) connection with the network. In 3GPP, the DC solution has evolved and is now also specified for NR as well as between LTE and NR. Multi-connectivity (MC) is the case when there are more than two nodes involved. With introduction of 5G, the term MR-DC (Multi-Radio Dual Connectivity) was defined as a generic term for all dual connectivity options that include at least one New Radio (NR) access node. Using the MR-DC generalized terminology, the UE is connected in a Master Cell Group (MCG), controlled by the Master Node (MN), and in a Secondary Cell Group (SCG) controlled by a Secondary Node (SN).

[0003] Further, in MR-DC, when dual connectivity is configured for the UE, within each of the two cell groups, MCG and SCG, carrier aggregation may be used as well. In this case, within the Master Cell Group, MCG, controlled by the master node (MN), the UE may use one PCell and one or more SCell(s). And within the Secondary Cell Group, SCG, controlled by the secondary node (SN), the UE may use one Primary SCell (PSCell, also known as the primary SCG cell in NR) and one or more SCell(s). This combined case is illustrated in Figure 1. In NR, the primary cell of a master or secondary cell group is sometimes also referred to as the Special Cell (SpCell). Hence, the SpCell in the MCG is the PCell and the SpCell in the SCG is the PSCell.

[0004] There are different ways to deploy a 5G network with or without interworking with LTE (also referred to as enhanced universal terrestrial radio access, or E-UTRA) and evolved packet core (EPC). In principle, NR and LTE can be deployed without any interworking, denoted by NR stand-alone (SA) operation, also known as Option 2. That is, the gNB in NR can be connected to a 5G core network (5GC) and the eNB in LTE can be connected to EPC with no interconnection between the two, also known as Option 1. [0005] On the other hand, the first supported version of NR uses dual connectivity, denoted as EN-DC (E-UTRAN-NR Dual Connectivity), also known as Option 3, as depicted in Figure 2. In such a deployment, dual connectivity between NR and LTE is applied, where the UE is connected with both the LTE radio interface (LTE Uu in the figure) to an LTE access node and the NR radio interface (NR Uu in the figure) to an NR access node. Further, in EN-DC, the LTE access node acts as the master node (in this case known as the Master eNB, MeNB), controlling the master cell group (MCG) and the NR access node acts as the secondary node (in this case sometimes also known as the Secondary gNB, SgNB), controlling the secondary cell group, SCG. The SgNB may not have a control plane connection to the core network (EPC) which instead is provided MeNB and in this case the NR. This is also called as “Non-standalone NR" or, in short, "NSA NR". Note that in this case, the functionality of an NR cell is limited and would be used for connected mode UEs as a booster and/or diversity leg, but an RRC_IDLE UE cannot camp on these NR cells.

[0006] With introduction of 5GC, other options may be also valid. As mentioned above, option 2 supports stand-alone NR deployment where gNB is connected to 5GC. Similarly, LTE can also be connected to 5GC using option 5 (also known as eLTE, E- UTRA/5GC, or LTE/5GC and the node can be referred to as an ng-eNB). In these cases, both NR and LTE are seen as part of the NG-RAN (and both the ng-eNB and the gNB can be referred to as NG-RAN nodes).

[0007] There are also other variants of dual connectivity between LTE and NR which have been standardized as part of NG-RAN connected to 5GC. Under the MR-DC umbrella are:

• EN-DC (Option 3): LTE is the master node and NR is the secondary node (EPC CN employed, as depicted in Figure 2.)

• NE-DC (Option 4): NR is the master node and LTE is the secondary (5GCN employed)

• NGEN-DC (Option 7): LTE is the master node and NR is the secondary (5GCN employed)

• NR-DC (variant of Option 2): Dual connectivity where both the master node, MN, controlling the MCG, and the secondary node, SN, controlling the SCG, are NR (5GCN employed, as depicted in Figure 3).

[0008] As migration for these options may differ from different operators, it is possible to have deployments with multiple options in parallel in the same network. For example, there could be an eNB base station supporting options 3, 5 and 7 in the same network as NR base station supporting options 2 and 4. In combination with dual connectivity solutions between LTE and NR it is also possible to support CA (Carrier Aggregation) in each cell group (i.e. MCG and SCG) and dual connectivity between nodes on same RAT (e.g. NR-NR DC). For the LTE cells, a consequence of these different deployments is the co-existence of LTE cells associated to eNBs connected to EPC, 5GC or both EPC/5GC.

[0009] As noted above, DC is standardized for both LTE and E-UTRA -NR DC (EN- DC). LTE DC and EN-DC are designed differently when it comes to which nodes control what. There are two options, namely, a centralized solution (like LTE-DC), and a decentralized solution (like EN-DC), as shown in Figure 4.

[0010] Figure 5 shows the schematic control plane architecture for LTE DC, EN-DC and NR-DC. The main difference here is that in EN-DC and NR-DC, the SN has a separate NR RRC entity. This means that the SN can control the UE also, sometimes without the knowledge of the MN but often the SN needs to coordinate with the MN. In LTE-DC, the RRC decisions are always coming from the MN (MN to UE). Note however, the SN still decides the configuration of the SN, since it is only the SN itself that has knowledge of what kind of resources, capabilities etc. it has.

[0011] For EN-DC and NR-DC, the major changes compared to LTE DC are the introduction of split bearer from the SN (known as SCG split bearer), the introduction of split bearer for RRC and the introduction of a direct RRC from the SN (also referred to as SCG SRB).

[0012] Figure 6 shows, from the network perspective, the user plane protocol architecture in MR-DC with EPC (EN-DC). In this case, the network can configure either E- UTRA packet data convergence protocol (PDCP) or NR PDCP for MN terminated MCG bearers while NR PDCP is always used for all other bearers.

[0013] Conditional Handover

[0014] In rel-16, conditional handover was standardized as a solution to increase the robustness at handover. In order to avoid the undesired dependence on the serving radio link upon the time (and radio conditions) where the UE should execute the handover, the possibility to provide RRC signaling for the handover to the UE earlier was standardized. It is possible to associate the HO command with a condition e.g. based on radio conditions possibly similar to the ones associated to an A3 event, where a given neighbor becomes X db better than a target. As soon as the condition is fulfilled, the UE executes the handover in accordance with the provided handover command.

[0015] Such a condition could, for example, be that the quality of the target cell or beam becomes X dB stronger than the serving cell. The threshold Y used in a preceding measurement reporting event should then be chosen 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 mobility Controlinfo at a time when the radio link between the source cell and the UE is still stable. The execution of the handover is done at a later point in time (and threshold) which is considered optimal for the handover execution.

[0016] Figure 7 depicts an example with just a serving and a target cell. In practice there may often be many cells or beams that the UE reported as possible candidates based on its preceding RRM measurements. The network should then have the freedom to issue conditional handover commands for several of those candidates. The RRCConnectionReconfiguration for each of those candidates may differ, for example, in terms of the HO execution condition (RS to measure and threshold to exceed) as well as in terms of the RA preamble to be sent when a condition is met.

[0017] While the UE evaluates the condition, it continues operating in accordance with its current RRC configuration, i.e., without applying the conditional HO command. When the UE determines that the condition is fulfilled, it disconnects from the serving cell, applies the conditional HO command and connects to the target cell. These steps are equivalent to the legacy handover execution.

[0018] Conditional PSCell Change (CPC)

[0019] A solution for a Conditional PSCell Change (CPC) procedure was also standardized in Rel-16. Therein a UE operating in Multi-Radio Dual Connectivity (MR-DC) receives in a conditional reconfiguration one or multiple RRC Reconfiguration(s) (e.g. an RRCReconfiguration message) containing an SCG configuration (e.g. an secondaryCellGroup of IE CellGroupConfig) with a reconfigurationWithSync that is stored and associated to an execution condition (e.g. a condition like an A3/A5 event configuration), so that one of the stored messages is only applied upon the fulfillment of the execution condition e.g. associated with the serving PSCell, upon which the UE would perform PSCell change (in case it find a neighbor cell that is better than the current SpCell of the SCG).

[0020] In rel-16 CPC will be supported, but in rel-17 also PSCell Addition will be included. The combination is referred to as Conditional PSCell Addition/Change (CPAC). In rel-16, only intra-SN CPC without MN involvement is standardized. Inter SN PSCell CPC and CPC with MN involvement will be included in rel-17.

[0021] Inter-SN CPC

[0022] In rel-17, solutions for inter-SN CPC are being discussed. It has been acknowledged and agreed in RAN2 that the S-SN measConfig may need to be updated after information has been received about which target cells that were ultimately selected by the T- SN. A solution called Solution 2 has been agreed, where the S-SN has the possibility to update the configuration to the UE. It is up to MN implementation to determine whether to configure the UE or not, before receiving an updated configuration from the S-SN. The current Stage-2 signaling flow of Solution 2 is shown in Figure 8.

[0023] The messages in the signaling flow are still being discussed, and another way to visualize the signaling is shown in Figure 9.

[0024] In case all candidate target cells were accepted by T-SN, the message in step 4 and 5 of Figure 9 are not necessary to be performed. Thus, the signaling can be reduced to the flow shown in Figure 10.

SUMMARY

[0025] A method performed by a first network node, operating as a master node (MN) for a user equipment (UE) in multi-radio dual connectivity (MR-DC) is provided. The first network node is associated to a second network node operating as a source secondary node (S- SN) for the UE, and the UE is configured with a conditional PSCell change (CPC) configuration for a target candidate secondary node (TC-SN). The method includes receiving from the S-SN a first message indicating that a first S-SN related configuration of the UE is to be modified, and indicating whether the S-SN related configuration modification impacts TC-SN target configurations for CPC, and determining, based on the first message, whether or not a procedure for modification of CPC target configurations towards the TC-SN needs to be triggered.

[0026] The method may further include triggering a CPC modification procedure towards the TC-SN in response to the first message.

[0027] The method may further include updating a configuration of the UE in response to the first message.

[0028] The configuration of the UE may include a S-SN configuration or TC-SN configuration.

[0029] The method may further include updating the configuration of the UE in response to the first message without triggering a CPC modification procedure towards the TC- SN.

[0030] The first S-SN related configuration may include one or more of: i) a CPC execution condition and/or mapping to a target candidate cell, ii) an indication that the CPC execution condition is to be released or removed, iii) a measurement configuration for CPC, iv) a secondary cell group, SCG, configuration to the UE that is to be deleted upon CPC execution, and/or iv) an SCG configuration that is not part of the UE’s SCG configuration used as reference for a target candidate configuration to be applied upon execution.

[0031] The first message may include a SN Modification Required message, a SN Change Required message or an SN Modification Request message.

[0032] The first message may include an explicit indication that indicates whether or not a CPC modification procedure should be triggered towards the TC-SN.

[0033]

[0034] The explicit indication may include an information element indicating that a CPC modification procedure should or should not be triggered towards the TC-SN.

[0035] The first message may include an implicit indication that indicates whether or not a CPC modification procedure should be triggered towards the TC-SN.

[0036] The first message may include an SN Modification Request Acknowledge or an SN Modification Required, and the first network node may determine that a CPC modification procedure is not needed towards the TC-SN in response to the first message.

[0037] The first message may include an SN Change Required message, and the first network node may determine that a CPC modification procedure is needed towards the TC-SN in response to the first message.

[0038] The determination of whether a CPC modification procedure should be triggered may additionally be based on further information received from the TC-SN. The further information may include an indication that a full configuration has been provided for a secondary cell group, SCG, configuration to be applied upon CPC execution.

[0039] Some embodiments provide a method performed by a second network node, operating as a S-SN for a UE operating in MR-DC, wherein the S-SN is associated to a first network node operating as a MN and the UE is configured with a CPC configuration for a TC- SN. The method includes transmitting to the MN a first message indicating to the MN that a first S-SN related configuration is to be modified, and indicating whether or not a CPC modification procedure should be triggered towards the TC-SN in response to the first message.

[0040] The first S-SN related configuration may include one or more of: i) a CPC execution condition and/or mapping to a target candidate cell, ii) an indication that the CPC execution condition is to be released or removed, iii) a measurement configuration for CPC, iv) a secondary cell group, SCG, configuration to the UE that is to be deleted upon CPC execution, and/or iv) an SCG configuration that is not part of the UE’s SCG configuration used as reference for a target candidate configuration to be applied upon execution. [0041] The first message may include a SN Modification Required message, a SN Change Required message or an SN Modification Request message.

[0042] The first message may include an explicit indication that indicates whether or not a CPC modification procedure should be triggered towards the TC-SN.

[0043] The explicit indication may include an information element in the first message indicating that a CPC modification procedure should or should not be triggered towards the TC- SN.

[0044] The first message may include an implicit indication that indicates whether or not a CPC modification procedure should be triggered towards the TC-SN.

[0045] The first message may include an SN Modification Request Acknowledge message or an SN Modification Required message and indicates that a CPC modification procedure is not needed towards the TC-SN in response to the first message.

[0046] The first message may include an SN Change Required message and indicates that a CPC modification procedure is needed towards the TC-SN in response to the first message.

[0047] Some embodiments provide a network node including a processing circuit and a memory coupled to the processing circuit. The memory includes computer readable program instructions that, when executed by the processing circuit, cause the network node to perform operations according to any of the foregoing embodiments.

[0048] Some embodiments provide a first network node, operating as a MN for a UE in MR-DC, wherein the MN is associated to a second network node operating as a S-SN and wherein the UE is configured with a CPC configuration for a TC-SN. The first network node is configured to receive from the S-SN a first message indicating that a first S-SN related configuration is to be modified, and indicating whether the S-SN related configuration modification impacts TC-SN target configurations for CPC, and determine, based on the first message, whether or not a procedure for modification of CPC target configurations towards the TC-SN needs to be triggered.

[0049] Some embodiments provide a second network node, operating as a S-SN for a UE operating in MR-DC, wherein the S-SN is associated to a first network node operating as a MN and the UE is configured with a CPC configuration for a TC-SN. The second network node is configured to transmit to the MN a first message indicating to the MN that a first S-SN related configuration is to be modified, and indicating whether or not a CPC modification procedure should be triggered towards the TC-SN in response to the first message. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 illustrates a master cell group and a secondary cell group that serve a UE.

[0051] Figure 2 illustrates Dual Connectivity configuration Option 3, EN-DC.

[0052] Figure 3 illustrates Dual Connectivity Option configuration 4, NR-DC.

[0053] Figure 4 illustrates EN-DC and NR-DC.

[0054] Figure 5 shows a schematic control plane architecture for LTE DC, EN-DC and NR-DC.

[0055] Figure 6 shows, from the network perspective, the user plane protocol architecture in MR-DC with EPC (EN-DC).

[0056] Figure 7 depicts an example with just a serving and a target cell.

[0057] Figures 8 and 9 illustrate a signalling flow for Conditional PSCell Change.

[0058] Figure 10 illustrates a simplified signalling flow for Conditional PSCell Change.

[0059] Figure 11 illustrates a signalling flow for Conditional PSCell Change in which the S-SN triggers an SN modification procedure after the UE has been configured with inter-SN CPC.

[0060] Figures 12 and 13 illustrate operations of network nodes according to some embodiments.

[0061] Figures 14 and 15 are flow diagrams illustrating message flows according to some embodiments.

[0062] Figure 16 shows an example of a communication system in accordance with some embodiments.

[0063] Figure 17 shows an example of a UE in accordance with some embodiments.

[0064] Figure 18 shows an example of a network node in accordance with some embodiments.

[0065] Figure 19 shows an example of a host node in accordance with some embodiments.

[0066] Figure 20 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized.

[0067] Figure 21 shows a communication diagram of a host communicating via a network node with a UE over a partially wireless connection in accordance with some embodiments. DETAILED DESCRIPTION

[0068] A problem in the existing solutions is that the S-SN may trigger another modification procedure possibly after the UEn has been configured with inter-SN CPC. In a signaling flow as in Figure 9 above, a situation as shown in Figure 11 may occur.

[0069] The problem to be solved is that upon receiving a new SCG configuration for the UE from the S-SN, the MN may not be able to determine whether or not the new SCG configuration should trigger a CPC modification procedure from the MN towards the Target Candidate SN(s) (so the MN can directly reconfigure the UE).

[0070] As can be seen in Figure 11, the MN does not know whether the message from the S-SN, e.g. SN Modification Required, with modification of the S-SN configuration received from the S-SN (e.g. SCG configuration) impacts the CPC configuration prepared by at least one target candidate SN (TC-SN) or whether the S-SN triggered a modification procedure may not require an update towards TC-SNs. This lack of knowledge may lead to certain problems.

[0071] For example, the MN may unnecessarily trigger CPC modification procedures towards target candidate SN(s), even in the case the modification of the SCG does not impact the target candidate SN(s). This might be the case, for example, if the SCG configuration only changes a measurement configuration related to the CPC configuration at the UE.

[0072] Also, the MN may not trigger a CPC modification procedures towards target candidate SN(s), even though the modification of the SCG impact the target candidate SN(s). This might be the case, for example, if a TC-SN provided a delta configuration to be applied on the top of UE’s current SCG configuration at the time of execution.

[0073] In other words, the MN is not aware whether or not the change being requested to the UE’s configuration from the S-SN (e.g. in the SCG) impacts the CPC configuration towards TC-SNs i.e. whether the MN needs to update a target candidate SN in response to the update to the UE’s SCG configuration.

[0074] For example, if the S-SN considered the CPC configuration procedure to be finalized and triggered a modification of the configuration which potentially could impact the target candidate configuration, the MN would need to forward the modification request to the T- SN and receive a new target configuration for the UE. On the other hand, if the S-SN triggered modification of a measurement configuration (measConfig) related to the ongoing CPC configuration, the MN does not have to ask the candidate target SN for new target configuration, but instead only needs to reconfigure the UE. The S-SN configuration is sent to the MN in a container that is transparent to the MN. That means that currently there is no possibility for the MN to know whether a modification procedure triggered by the S-SN is for a different modification procedure or whether it belongs to the CPC configuration procedure.

[0075] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. In particular, some embodiments provide a method for a network node operating as MN to distinguish whether a modification procedure triggered by a S-SN is related to a CPC configuration procedure or whether it is a separate modification procedure, and for a S-SN to inform the MN whether a modification procedure triggered by a S-SN is related to a CPC configuration procedure or whether it is a separate modification procedure.

[0076] For example, referring to Figure 12, some embodiments provide a method in a first network node, operating as a MN for a UE in MR-DC, wherein the MN is associated to a S- SN and the UE is configured with a CPC configuration for the target candidate Secondary Node (TC-SN). The method includes receiving (block 502) from the S-SN a first message indicating that i) a first S-SN related configuration to be modified, and ii) indicating whether the S-SN related configuration modification impacts TC-SN target configurations for CPC and determining (block 504), based on the first message, whether a procedure for modification of CPC target configurations towards the TC-SN needs to be triggered.

[0077] The first S-SN related configuration can be one or more of the following: i) the CPC execution condition(s) and/or the mapping to target candidate cell(s); ii) indication(s) that the CPC execution condition(s) are to be released/ removed; iii) a measConfig for CPC; iv) in more general terms, an SCG configuration to the UE that is known to be deleted upon CPC execution; iv) in more general terms, an SCG configuration which is not part of the UE’s SCG configuration used as reference for the target candidate configuration to be applied upon execution;

[0078] The first message can be one of the following: i) SN Modification Required; ii) SN Change Required; iii) SN Modification Request.

[0079] There may be different ways for the first message to indicate whether a CPC modification procedure towards one or more TC-SN(s) needs to be triggered. In one option, the first message can include an indication, e.g., an information element in the first message, that a CPC modification procedure towards one or more TC-SN(s) needs to be triggered by the MN, or the absence of an indication indicates that.

[0080] In another option, the first message itself indicates that a CPC modification procedure towards one or more TC-SN(s) needs to be triggered by the MN, or not. For example, if the first message is an SN Modification Request Acknowledge or an SN Modification Required, the MN determines that a CPC modification procedure towards one or more TC-SN(s) is NOT needed, else if the first message is an SN Change Required a CPC modification procedure towards one or more TC-SN(s).

[0081] In another option, the MN determines based on the first message, but also based on further information previously received from the TC-SN(s), such as an indication that a full configuration has been provided for the SCG configuration to be applied upon CPC execution. In that case, no matter how the UE’s SCG configuration is modified by the S-SN, the TC-SN configuration would not be affected by it.

[0082] Still referring to Figure 12, if the MN determines at block 504 that a procedure for modification of CPC target configurations towards the TC-SN needs to be triggered, the MN triggers (block 506) the CPC modification procedure towards one or more TC-SN(s) by transmitting a second message and receives a third message including a new configuration for the UE and modifies/updates the UE based on the new configuration.

[0083] Alternatively, if the MN determines at block 504, based on the first message, that a procedure for modification of CPC target configurations towards the TC-SN does not need to be triggered, the MN modifies/updates the UE based on the first S-SN related configuration to be modified without triggering a CPC modification procedure towards a TC-SN (block 508).

[0084] Referring to Figure 13, some embodiments provide a method in a second network node, operating as a S-SN for a UE in MR-DC, wherein the S-SN is associated to a MN and the UE is configured with a CPC configuration for at least one TC-SN. The method includes transmitting (block 602) to the MN a first message indicating to the MN that i) a first S-SN related configuration to be modified, and ii) indicating whether a CPC modification procedure towards one or more TC-SN(s) needs to be triggered by the MN upon receipt of the first message from the S-SN. The MN determines, based on the first message, whether a CPC modification procedure towards one or more TC-SN(s) needs to be triggered or not.

[0085] The first message can be one of i) a SN Modification Required; ii) a SN Change Required; and iii) a SN Modification Request.

[0086] In some embodiments, the S-SN includes in the first message an indication, e.g., an information element in the first message, that a CPC modification procedure towards one or more TC-SN(s) needs to be triggered by the MN, or the absence of an indication indicates that.

[0087] In another option, the S-SN determines which message is the first message to indicate that a CPC modification procedure towards one or more TC-SN(s) needs to be triggered by the MN, or not. For example, if S-SN determines that the first S-SN related configuration to be modified requires the MN to trigger a CPC modification procedure towards one or more TC- SN(s), the S-SN transmits an SN Change Required, so that upon reception the MN is aware that it needs to trigger the CPC modification procedure towards one or more TC-SN(s). if S-SN determines that the first S-SN related configuration to be modified does not require the MN to trigger a CPC modification procedure towards one or more TC-SN(s), the S-SN transmits an SN Modification Required, so that upon reception the MN is aware that it does not need to trigger the CPC modification procedure towards one or more TC-SN(s).

[0088] Certain embodiments may provide one or more of the following technical advantage(s). For example, in some embodiments, the MN knows if a modification procedure triggered by an S-SN is linked to a CPC preparation procedure or not, and thereby knows which action it needs to take, e.g. whether it needs to contact target candidate SN(s) or not. Thus, with this information available to the MN, network signaling can be reduced and the preparation time for CPC can be reduced.

[0089] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art. Additional information may also be found in the document(s) provided in the Appendix.

[0090] The description below refers to a first network node operating as a Master Node (MN), e.g. having a Master Cell Group (MCG) configured to the UE and/or an MN- terminated bearer; that MN can be a gNodeB, or a Central Unit gNodeB (CU-gNB) or an eNodeB, or a Central Unit eNodeB (CU-eNB), or any network node and/or network function. The description also refers to a second network node operating as a Secondary Node (SN), or Source Secondary Node (S-SN) e.g. having a Secondary Cell Group (SCG) pre-configured (i.e. not connected to) to the UE; that SN can be a gNodeB, or a Central Unit gNodeB (CU-gNB) or an eNodeB, or a Central Unit eNodeB (CU-eNB), or any network node and/or network function. Notice that MN, S-SN and T-SN may be from the same or different Radio Access Technologies (and possibly be associated to different Core Network nodes).

[0091] The description below refers to a “Secondary Node (SN)”, or target SN, T-SN. This is equivalent to say this is a target candidate SN,TC-SN, or a network node associated to a target candidate PSCell that is being configured. If the UE would connect to that cell, transmissions and receptions with the UE would be handled by that node if the cell is associated to that node.

[0092] The description below states that a cell resides in a node, for example, a target candidate cell resides in the S-SN or the t-SN. That is equivalent to saying that a cell is managed by the node, or is associated to the node, or associated with the node, or that the cell belongs to the node, or that the cell is of the node.

[0093] “SN-initiated CPC” corresponds to a procedure wherein the Source SN for a UE configured with MR-DC determines to configure CPC. Upon determining the Source SN selects e.g. based on reported measurements, one or more target candidate cells (target candidate PSCell(s)) wherein at least one cell is associated to the Source SN, and at least another cell is associated to a neighbor SN. It can be said that if all target candidate cells are associated to the Source SN that is an “SN-initiated intra-SN CPC”, which may be referred as the Release 16 solution. It can be said that if at least one target candidate cell is associated to the a neighbor SN that is an “SN-initiated inter-SN CPC”, which may be referred as a Release 17 solution.

[0094] The description below refers to a candidate SN, or SN candidate, or an SN, as the network node (e.g. gNodeB) that is prepared during the CPA procedure and that can create an RRC Reconfiguration message with an SCG configuration (e.g. RRCReconfiguration**) to be provided to the UE and stored, with an execution condition, wherein the UE only applies the message upon the fulfillment of the execution condition. That candidate SN is associated to one or multiple PSCell candidate cell(s) that the UE can be configured with. The UE then can execute the condition and accesses one of these candidate cells, associated to a candidate SN that becomes the SN or simply the SN after execution (i.e. upon fulfillment of the execution condition).

[0095] The description below refers to a CPC configuration and procedures (such as CPC execution), most of the time to refer to the procedure from the UE perspective. Other terms may be considered as synonyms such as conditional reconfiguration, or Conditional Configuration (since the message that is stored and applied upon fulfillment of a condition is an RRCReconfiguration or RRCConnectionReconfiguratiori). Terminology wise, one could also interpret conditional handover (CHO) in a broader sense, also covering CPA (Conditional PSCell Change) procedures. The document refers to a Conditional SN Change most of the time to refer to the procedure from the UE perspective, to refer to procedures between network nodes wherein a node requests a target candidate SN (which may be the same as the Source SN or a neighbor SN) to configure a CPC for at least one of its associated cells (cell associated to the target candidate SN).

[0096] The description below refers to CPAC as a way to refer to either a Conditional PSCell Addition (CPA) or a Conditional PSCell Change (CPC).

[0097] The description below refers to a neighbor SN and a Source SN as different entities, though both could be a target candidate SN for CPC. [0098] The configuration of CPC can be done using the same IES as conditional handover, which may be called at some point conditional configuration or conditional reconfiguration. The principle for the configuration is the same with configuring triggering/execution condition(s) and a reconfiguration message to be applied when the triggering condition(s) are fulfilled. The configuration IEs from TS 38.331 include the ConditionalReconfiguration IE, the CondConfigld information element and the CondConfigtoAddMod information element.

[0099] Figure 14 is flow diagram illustrating message flows according to some embodiments. Referring to Figure 14, a MN receives a request 702, e.g. a SN Change Required, from a S-SN to configure CPC. The MN then transmits a request 704, e.g. SN Addition Request, to target candidate SN, T-SN, for configuration of CPC. The MN then receives a response 706 from T-SN, e.g. SN Addition Request Acknowledge, where some candidate target cells were accepted and some candidate target cells were not accepted.

[0100] The MN then determines at block 708 whether to configure the UE. If the MN determines to configure the UE, the MN sends an RRCReconfiguration message 710 to the UE, which responds with RRCReconfigurationComplete 712.

[0101] The MN then transmits a response message 714, e.g. SN Change Confirm, SN Modification Request or another message or a new message, to S-SN, including a list of accepted and/or rejected target cells. At block 716, the S-SN determines whether the measurement configuration (measConfig) of the UE needs to be updated.

[0102] The MN then receives a first message 718 including a request for modification of the S-SN part of the UE configuration, e.g. an SN Modification Required or SN Change Required, from the S-SN.

[0103] The MN then determines at block 720, based on the first message, whether a CPC modification procedure towards one or more TC-SN(s) needs to be triggered or not in response to the first message 718.

[0104] There may be different ways for the first message to indicate whether a CPC modification procedure needs to be triggered. In one option, the first message can include an indication, such as an information element in the first message, indicating that a CPC modification procedure towards one or more TC-SN(s) needs to be triggered by the MN. In some embodiments, the absence of an indication may indicate whether or not a CPC modification procedure should be triggered towards a TC-SN.

[0105] In another option, the first message itself indicates whether or not a CPC modification procedure towards one or more TC-SN(s) needs to be triggered by the MN. For example, if the first message is an SN Modification Request Acknowledge or an SN Modification Required, the MN determines that a CPC modification procedure towards one or more TC-SN(s) is not needed. Otherwise, if the first message is an SN Change Required, then a CPC modification procedure is needed towards one or more TC-SN(s).

[0106] The SN Modification Required message, or other modification message, contains a list of target candidate cells, where the cells are a subset of the list of cells which were accepted by the T-SN.

[0107] The SN Modification Required message may be received by the MN while the SN Change procedure for CPC is ongoing or within a certain time after indicating that there may be a need for the second step of the SN initiated CPC.

[0108] In another option, the MN determines whether or not to trigger a CPC modification procedure based on the first message, but also based on further information previously received from the TC-SN(s), such as an indication that a full configuration has been provided for the SCG configuration to be applied upon CPC execution or, alternatively, another indication by the TC-SN(s) that the TC-SN(s) configuration for CPC does not need to be updated in case CPC is updated. In that case, no matter how the UE’ s SCG configuration is modified by the S-SN, the TC-SN configuration would not be affected by it.

[0109] If the SN Modification Required is related to the ongoing CPC configuration procedure, the MN transmits an RRCReconfiguration message 722 to the UE without contacting T-SN(s). The UE responds with an RRCReconfigurationComplete message 724.

[0110] The MN may receive a response message back from the UE, e.g. an RRCReconfigurationComplete.

[0111] The MN then transmits a response message 726 back to S-SN, e.g. an SN Modification Confirm, the message containing a response message from the UE, e.g. an RRCReconfigurationComplete.

[0112] If the SN Modification is not related to the ongoing CPC configuration procedure, the MN may perform other actions. For example, if the SN Modification Required does not contain any indication of relation with the ongoing CPC configuration procedure, the MN may transmit an SN Modification Request to T-SN, and receive a response back, e.g. SN Modification Request Acknowledge. The MN may then transmit an RRCReconfiguration message to the UE.

[0113] Alternatively, the MN may cancel the previous CPC configurations and trigger a new CPC configuration procedure. [0114] The UE then executes the CPC at block 728 and sends RRCReconfigurationComplete 730 to the MN, which is forwarded by the MN to the S-SN.

[0115] Operations of a source Secondary Node (SN) illustrated in Figure 14 include transmitting a request 702 to an MN to configure inter-SN CPC, and receiving a response message 714, e.g. SN Change Confirm, SN Modification Request or another message or a new message, from MN, the message including a list of accepted and/or rejected target cells. The SN transmits a first message 718 containing a request for modification of UE configuration. The request indicates whether the request is linked to a CPC preparation procedure. For example, the message 718 may indicated that only the S-SN measConfig has been updated, or whether it is a new modification procedure, indicating that the S-SN configuration may have been updated.

[0116] In one option, the message 718 can include an indication, such as an information element in the first message, that a CPC modification procedure towards one or more TC-SN(s) needs to be triggered by the MN, or the absence of an indication indicates that.

[0117] In another option, the first message 718 itself indicates whether or not a CPC modification procedure towards one or more TC-SN(s) needs to be triggered by the MN. For example, if the first message 718 is an SN Modification Request Acknowledge or an SN Modification Required, the MN determines that a CPC modification procedure towards one or more TC-SN(s) is not needed. Otherwise, if the first message is an SN Change Required, a CPC modification procedure towards one or more TC-SN(s) is triggered by the MN.

[0118] The first message 718, e.g. SN Modification Required, or other modification message, contains a list of target candidate cells, where the cells are a subset of the list of cells which were accepted by the T-SN.

[0119] The first message 718, for example, a SN Modification Required, may be sent to the MN while the SN Change procedure for CPC is ongoing or within a certain time after having received an indication from the MN that there may be a need for the second step of the SN initiated CPC.

[0120] The SN receives a response message 726 back from the MN, e.g. an SN Change Confirm or an SN Modification Confirm, containing a response message from the UE, such as an RRCReconfigurationComplete.

[0121] In another case illustrated in Figure 15, the UE was not configured by the MN after the reply 706 back from TC-SN, but the MN decides to first contact the S-SN for an update of the S-SN part of the UE configuration. Also, in this case it may happen that the S-SN decides to trigger another procedure which may collide with the ongoing CPC configuration procedure. The S-SN may, for example, decide to trigger a legacy PSCell Change procedure by sending a first message 718, such as a SN Change Required or an SN Modification Required message, to the MN. Also here, the MN needs to be able to know whether the modification message from the S-SN is a response to the message from the MN, or whether the S-SN triggered another procedure.

[0122] In one option, the first message 718 itself indicates whether or not a CPC modification procedure towards one or more TC-SN(s) needs to be triggered by the MN. For example, if the first message is an SN Modification Request Acknowledge, the MN determines that a CPC modification procedure towards one or more TC-SN(s) is NOT needed, else if the first message is an SN Modification Required or an SN Change Required a CPC modification procedure towards one or more TC-SN(s).

[0123] In one option, the first message 718 can include an indication, such as an information element in the first message, that a CPC modification procedure towards one or more TC-SN(s) needs to be triggered by the MN. Alternatively, the absence of an indication may indicate whether or not a CPC modification should be triggered.

[0124] The SN Modification Required, or other modification message, 718 may contain a list of target candidate cells, where the cells are a subset of the list of cells which were accepted by the T-SN.

[0125] The SN Modification Required may be received by the MN (or S-SN) while the SN Change procedure for CPC is ongoing or within a certain time after indicating that there may be a need for the second step of the SN initiated inter- SN CPC.

[0126] In another option, the MN determines based on the first message 718, but also based on further information previously received from the TC-SN(s), such as an indication that a full configuration has been provided for the SCG configuration to be applied upon CPC execution, or, alternatively, another indication by the TC-SN(s) that the TC-SN(s) configuration for CPC does not need to be updated in case CPC is updated. In that case, no matter how the UE’s SCG configuration is modified by the S-SN, the TC-SN configuration would not be affected by it.

[0127] Figure 16 shows an example of a communication system 1600 in accordance with some embodiments.

[0128] In the example, the communication system 1600 includes a telecommunication network 1602 that includes an access network 1604, such as a radio access network (RAN), and a core network 1606, which includes one or more core network nodes 1608. The access network 1604 includes one or more access network nodes, such as network nodes 1610a and 1610b (one or more of which may be generally referred to as network nodes 1610), or any other similar 3 ^rd Generation Partnership Project (3GPP) access node or non-3GPP access point. The network nodes 1610 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 1612a, 1612b, 1612c, and 1612d (one or more of which may be generally referred to as UEs 1612) to the core network 1606 over one or more wireless connections.

[0129] 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, the communication system 1600 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. The communication system 1600 may include and/or interface with any type of communication, telecommunication, data, cellular, radio network, and/or other similar type of system.

[0130] The UEs 1612 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and/or operable to communicate wirelessly with the network nodes 1610 and other communication devices. Similarly, the network nodes 1610 are arranged, capable, configured, and/or operable to communicate directly or indirectly with the UEs 1612 and/or with other network nodes or equipment in the telecommunication network 1602 to enable and/or provide network access, such as wireless network access, and/or to perform other functions, such as administration in the telecommunication network 1602.

[0131] In the depicted example, the core network 1606 connects the network nodes 1610 to one or more hosts, such as host 1616. 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. The core network 1606 includes one more core network nodes (e.g., core network node 1608) 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 1608. 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 (SIDE), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and/or a User Plane Function (UPF). [0132] The host 1616 may be under the ownership or control of a service provider other than an operator or provider of the access network 1604 and/or the telecommunication network 1602, and may be operated by the service provider or on behalf of the service provider. The host 1616 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.

[0133] As a whole, the communication system 1600 of Figure 16 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.

[0134] In some examples, the telecommunication network 1602 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 1602 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 1602. For example, the telecommunications network 1602 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.

[0135] In some examples, the UEs 1612 are configured to transmit and/or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 1604 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 1604. 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).

[0136] In the example, the hub 1614 communicates with the access network 1604 to facilitate indirect communication between one or more UEs (e.g., UE 1612c and/or 1612d) and network nodes (e.g., network node 1610b). In some examples, the hub 1614 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 1614 may be a broadband router enabling access to the core network 1606 for the UEs. As another example, the hub 1614 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 1610, or by executable code, script, process, or other instructions in the hub 1614. As another example, the hub 1614 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, the hub 1614 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 1614 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 1614 then provides to the UE either directly, after performing local processing, and/or after adding additional local content. In still another example, the hub 1614 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.

[0137] The hub 1614 may have a constant/persistent or intermittent connection to the network node 1610b. The hub 1614 may also allow for a different communication scheme and/or schedule between the hub 1614 and UEs (e.g., UE 1612c and/or 1612d), and between the hub 1614 and the core network 1606. In other examples, the hub 1614 is connected to the core network 1606 and/or one or more UEs via a wired connection. Moreover, the hub 1614 may be configured to connect to an M2M service provider over the access network 1604 and/or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 1610 while still connected via the hub 1614 via a wired or wireless connection. In some embodiments, the hub 1614 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 1610b. In other embodiments, the hub 1614 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 1610b, but which is additionally capable of operating as a communication start and/or end point for certain data channels. [0138] Figure 17 shows a UE 1700 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 (3GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE.

[0139] 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).

[0140] The UE 1700 includes processing circuitry 1702 that is operatively coupled via a bus 1704 to an input/output interface 1706, a power source 1708, a memory 1710, a communication interface 1712, and/or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 17. 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.

[0141] The processing circuitry 1702 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 the memory 1710. The processing circuitry 1702 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, the processing circuitry 1702 may include multiple central processing units (CPUs).

[0142] In the example, the input/output interface 1706 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 the UE 1700. 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.

[0143] In some embodiments, the power source 1708 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. The power source 1708 may further include power circuitry for delivering power from the power source 1708 itself, and/or an external power source, to the various parts of the UE 1700 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 1708. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 1708 to make the power suitable for the respective components of the UE 1700 to which power is supplied.

[0144] The memory 1710 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 readonly memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 1710 includes one or more application programs 1714, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1716. The memory 1710 may store, for use by the UE 1700, any of a variety of various operating systems or combinations of operating systems. [0145] The memory 1710 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.’ The memory 1710 may allow the UE 1700 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to offload data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 1710, which may be or comprise a device-readable storage medium.

[0146] The processing circuitry 1702 may be configured to communicate with an access network or other network using the communication interface 1712. The communication interface 1712 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 1722. The communication interface 1712 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 1718 and/or a receiver 1720 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 1718 and receiver 1720 may be coupled to one or more antennas (e.g., antenna 1722) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0147] In the illustrated embodiment, communication functions of the communication interface 1712 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.

[0148] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 1712, 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., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0149] 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.

[0150] 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 the UE 1700 shown in Figure 17. [0151] 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 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP 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.

[0152] 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.

[0153] Figure 18 shows a network node 1800 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 NR NodeBs (gNBs)).

[0154] 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).

[0155] 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).

[0156] The network node 1800 includes a processing circuitry 1802, a memory 1804, a communication interface 1806, and a power source 1808. The network node 1800 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 the network node 1800 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 NodeB s. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 1800 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1804 for different RATs) and some components may be reused (e.g., a same antenna 1810 may be shared by different RATs). The network node 1800 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1800, 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 1800.

[0157] The processing circuitry 1802 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 1800 components, such as the memory 1804, to provide network node 1800 functionality.

[0158] In some embodiments, the processing circuitry 1802 includes a system on a chip (SOC). In some embodiments, the processing circuitry 1802 includes one or more of radio frequency (RF) transceiver circuitry 1812 and baseband processing circuitry 1814. In some embodiments, the radio frequency (RF) transceiver circuitry 1812 and the baseband processing circuitry 1814 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 1812 and baseband processing circuitry 1814 may be on the same chip or set of chips, boards, or units. [0159] The memory 1804 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 the processing circuitry 1802. The memory 1804 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 capable of being executed by the processing circuitry 1802 and utilized by the network node 1800. The memory 1804 may be used to store any calculations made by the processing circuitry 1802 and/or any data received via the communication interface 1806. In some embodiments, the processing circuitry 1802 and memory 1804 is integrated.

[0160] The communication interface 1806 is used in wired or wireless communication of signaling and/or data between a network node, access network, and/or UE. As illustrated, the communication interface 1806 comprises port(s)/terminal(s) 1816 to send and receive data, for example to and from a network over a wired connection. The communication interface 1806 also includes radio front-end circuitry 1818 that may be coupled to, or in certain embodiments a part of, the antenna 1810. Radio front-end circuitry 1818 comprises filters 1820 and amplifiers 1822. The radio front-end circuitry 1818 may be connected to an antenna 1810 and processing circuitry 1802. The radio front-end circuitry may be configured to condition signals communicated between antenna 1810 and processing circuitry 1802. The radio front-end circuitry 1818 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 1818 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1820 and/or amplifiers 1822. The radio signal may then be transmitted via the antenna 1810. Similarly, when receiving data, the antenna 1810 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1818. The digital data may be passed to the processing circuitry 1802. In other embodiments, the communication interface may comprise different components and/or different combinations of components.

[0161] In certain alternative embodiments, the network node 1800 does not include separate radio front-end circuitry 1818, instead, the processing circuitry 1802 includes radio front-end circuitry and is connected to the antenna 1810. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1812 is part of the communication interface 1806. In still other embodiments, the communication interface 1806 includes one or more ports or terminals 1816, the radio front-end circuitry 1818, and the RF transceiver circuitry 1812, as part of a radio unit (not shown), and the communication interface 1806 communicates with the baseband processing circuitry 1814, which is part of a digital unit (not shown).

[0162] The antenna 1810 may include one or more antennas, or antenna arrays, configured to send and/or receive wireless signals. The antenna 1810 may be coupled to the radio front-end circuitry 1818 and may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In certain embodiments, the antenna 1810 is separate from the network node 1800 and connectable to the network node 1800 through an interface or port.

[0163] The antenna 1810, communication interface 1806, and/or the processing circuitry 1802 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, the antenna 1810, the communication interface 1806, and/or the processing circuitry 1802 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.

[0164] The power source 1808 provides power to the various components of network node 1800 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1808 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1800 with power for performing the functionality described herein. For example, the network node 1800 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 the power source 1808. As a further example, the power source 1808 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.

[0165] Embodiments of the network node 1800 may include additional components beyond those shown in Figure 18 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, the network node 1800 may include user interface equipment to allow input of information into the network node 1800 and to allow output of information from the network node 1800. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1800.

[0166] Figure 19 is a block diagram of a host 1900, which may be an embodiment of the host 1616 of Figure 16, in accordance with various aspects described herein. As used herein, the host 1900 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. The host 1900 may provide one or more services to one or more UEs.

[0167] The host 1900 includes processing circuitry 1902 that is operatively coupled via a bus 1904 to an input/output interface 1906, a network interface 1908, a power source 1910, and a memory 1912. 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 17 and 18, such that the descriptions thereof are generally applicable to the corresponding components of host 1900.

[0168] The memory 1912 may include one or more computer programs including one or more host application programs 1914 and data 1916, which may include user data, e.g., data generated by a UE for the host 1900 or data generated by the host 1900 for a UE. Embodiments of the host 1900 may utilize only a subset or all of the components shown. The host application programs 1914 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). The host application programs 1914 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, the host 1900 may select and/or indicate a different host for over-the-top services for a UE. The host application programs 1914 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.

[0169] Figure 20 is a block diagram illustrating a virtualization environment 2000 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 2000 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.

[0170] Applications 2002 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and/or benefits of some of the embodiments disclosed herein.

[0171] Hardware 2004 includes processing circuitry, memory that stores software and/or instructions 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 2006 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 2008a and 2008b (one or more of which may be generally referred to as VMs 2008), and/or perform any of the functions, features and/or benefits described in relation with some embodiments described herein. The virtualization layer 2006 may present a virtual operating platform that appears like networking hardware to the VMs 2008.

[0172] The VMs 2008 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 2006. Different embodiments of the instance of a virtual appliance 2002 may be implemented on one or more of VMs 2008, 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.

[0173] In the context of NFV, a VM 2008 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 the VMs 2008, and that part of hardware 2004 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 2008 on top of the hardware 2004 and corresponds to the application 2002.

[0174] Hardware 2004 may be implemented in a standalone network node with generic or specific components. Hardware 2004 may implement some functions via virtualization. Alternatively, hardware 2004 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 2010, which, among others, oversees lifecycle management of applications 2002. In some embodiments, hardware 2004 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 2012 which may alternatively be used for communication between hardware nodes and radio units.

[0175] Figure 21 shows a communication diagram of a host 2102 communicating via a network node 2104 with a UE 2106 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as a UE 1612a of Figure 16 and/or UE 1700 of Figure 17), network node (such as network node 1610a of Figure 16 and/or network node 1800 of Figure 18), and host (such as host 1616 of Figure 16 and/or host 1900 of Figure 19) discussed in the preceding paragraphs will now be described with reference to Figure 21.

[0176] Eike host 1900, embodiments of host 2102 include hardware, such as a communication interface, processing circuitry, and memory. The host 2102 also includes software, which is stored in or accessible by the host 2102 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 the UE 2106 connecting via an over-the-top (OTT) connection 2150 extending between the UE 2106 and host 2102. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection 2150.

[0177] The network node 2104 includes hardware enabling it to communicate with the host 2102 and UE 2106. The connection 2160 may be direct or pass through a core network (like core network 1606 of Figure 16) 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.

[0178] The UE 2106 includes hardware and software, which is stored in or accessible by UE 2106 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 2106 with the support of the host 2102. In the host 2102, an executing host application may communicate with the executing client application via the OTT connection 2150 terminating at the UE 2106 and host 2102. 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. The OTT connection 2150 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 the OTT connection 2150.

[0179] The OTT connection 2150 may extend via a connection 2160 between the host 2102 and the network node 2104 and via a wireless connection 2170 between the network node 2104 and the UE 2106 to provide the connection between the host 2102 and the UE 2106. The connection 2160 and wireless connection 2170, over which the OTT connection 2150 may be provided, have been drawn abstractly to illustrate the communication between the host 2102 and the UE 2106 via the network node 2104, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

[0180] As an example of transmitting data via the OTT connection 2150, in step 2108, the host 2102 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 the UE 2106. In other embodiments, the user data is associated with a UE 2106 that shares data with the host 2102 without explicit human interaction. In step 2110, the host 2102 initiates a transmission carrying the user data towards the UE 2106. The host 2102 may initiate the transmission responsive to a request transmitted by the UE 2106. The request may be caused by human interaction with the UE 2106 or by operation of the client application executing on the UE 2106. The transmission may pass via the network node 2104, in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step 2112, the network node 2104 transmits to the UE 2106 the user data that was carried in the transmission that the host 2102 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 2114, the UE 2106 receives the user data carried in the transmission, which may be performed by a client application executed on the UE 2106 associated with the host application executed by the host 2102. [0181] In some examples, the UE 2106 executes a client application which provides user data to the host 2102. The user data may be provided in reaction or response to the data received from the host 2102. Accordingly, in step 2116, the UE 2106 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 the UE 2106. Regardless of the specific manner in which the user data was provided, the UE 2106 initiates, in step 2118, transmission of the user data towards the host 2102 via the network node 2104. In step 2120, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 2104 receives user data from the UE 2106 and initiates transmission of the received user data towards the host 2102. In step 2122, the host 2102 receives the user data carried in the transmission initiated by the UE 2106.

[0182] One or more of the various embodiments improve the performance of OTT services provided to the UE 2106 using the OTT connection 2150, in which the wireless connection 2170 forms the last segment. More precisely, the teachings of these embodiments may improve the efficiency of conditional PSCell change operations and thereby provide benefits such as reduced network overhead.

[0183] In an example scenario, factory status information may be collected and analyzed by the host 2102. As another example, the host 2102 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host 2102 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, the host 2102 may store surveillance video uploaded by a UE. As another example, the host 2102 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, the host 2102 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.

[0184] 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 the OTT connection 2150 between the host 2102 and UE 2106, 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 the host 2102 and/or UE 2106. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection 2150 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 the OTT connection 2150 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of the network node 2104. 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 the host 2102. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 2150 while monitoring propagation times, errors, etc.

[0185] Although the computing devices described herein (e.g., UEs, network nodes, hosts) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and/or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and/or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and/or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0186] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer- readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non- transitory computer- readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and/or by end users and a wireless network generally.