Related Applications

The present application claims priority to U.S. Provisional Patent Application No. 62/544,281, filed August 11 , 2017, entitled "HANDLING ROAMING RESTRICTIONS IN A MOBILE NETWORK", the entire disclosure of which is hereby incorporated by reference.

Technical Field

The present disclosure relates to the field of mobile networks. More particularly, the present disclosure relates to management of network connections within multiple radio access technology mobile networks.

Background

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.

Introduction of new radio (NR) technology (otherwise known as fifth generation (5G) technology or 5G NR technology) will result in changes in mobile network architecture. These changes in mobile network architecture may result in mobile network architectures supporting multiple radio access technologies, such as NR technology, evolved packet core (EPC) technology, evolved universal mobile telecommunication system terrestrial radio access network (E-UTRAN) technology, global system for mobile communications evolution radio access network (GERAN) technology, and universal mobile telecommunication system terrestrial radio access network (UTRAN). Management of user equipment (UE) connections within these mobile network architectures supporting multiple radio access technologies may introduce situations that did not need to be addressed in legacy mobile network architectures.

Brief Description of the Drawings

Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements. Embodiments are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings.

Figure 1 illustrates an example mobile network scenario, according to various embodiments.

Figure 2 illustrates an example network architecture, according to various embodiments.

Figure 3 illustrates a message flow of an example registration request procedure, according to various embodiments.

Figure 4 illustrates a message flow of an example registration request procedure, according to various embodiments.

Figure 5 illustrates an example connection procedure, according to various embodiments.

Figure 6 illustrates another example connection procedure, according to various embodiments.

Figure 7 illustrates an architecture of a system of a network in accordance with some embodiments.

Figure 8 illustrates an architecture of a system of a network in accordance with some embodiments.

Figure 9 illustrates example components of a device in accordance with some embodiments.

Figure 10 illustrates example interfaces of baseband circuitry in accordance with some embodiments.

Figure 11 is an illustration of a control plane protocol stack in accordance with some embodiments.

Figure 12 is an illustration of a user plane protocol stack in accordance with some embodiments.

Figure 13 illustrates components of a core network in accordance with some embodiments.

Figure 14 is a block diagram illustrating components, according to some example embodiments, of a system to support network functions virtualization (NFV).

Figure 15 is a block diagram illustrating components, according to some example embodiments, able to read instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and perform any one or more of the methodologies discussed herein. Detailed Description

Herein described are apparatuses, methods and storage media associated with management of network connections within multiple radio access technology mobile networks. In embodiments, one or more computer-readable media may have instructions stored thereon, wherein the instructions, in response to execution by a user equipment (UE), may cause the UE to generate a registration request for transmission to a network, identify a registration reject message received from the network in response to the registration request, wherein the registration reject message includes an indication that Nl mode is not allowed, and disable Nl mode radio capability based on the indication.

In the following detailed description, reference is made to the accompanying drawings which form a part hereof wherein like numerals designate like parts throughout, and in which is shown by way of illustration embodiments that may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments is defined by the appended claims and their equivalents.

Aspects of the disclosure are disclosed in the accompanying description. Alternate embodiments of the present disclosure and their equivalents may be devised without parting from the spirit or scope of the present disclosure. It should be noted that like elements disclosed below are indicated by like reference numbers in the drawings.

Various operations may be described as multiple discrete actions or operations in turn, in a manner that is most helpful in understanding the claimed subject matter.

However, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations may not be performed in the order of presentation. Operations described may be performed in a different order than the described embodiment. Various additional operations may be performed and/or described operations may be omitted in additional embodiments.

For the purposes of the present disclosure, the phrase "A and/or B" means (A), (B), or (A and B). For the purposes of the present disclosure, the phrase "A, B, and/or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

The description may use the phrases "in an embodiment," or "in embodiments," which may each refer to one or more of the same or different embodiments. Furthermore, the terms "comprising," "including," "having," and the like, as used with respect to embodiments of the present disclosure, are synonymous. As used herein, the term "circuitry" may refer to, be part of, or include an

Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and/or memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality.

With the advent of fifth generation (5G) network technology, mobile network configurations simultaneously support user equipments (UEs) with different capabilities within a single mobile network. For example, a single mobile network may be expected to support both evolved packet core (EPC) and fifth generation core network (which may be referred to as "5G CN" or "5GC") protocols.

Figure 1 illustrates an example mobile network scenario 100, according to various embodiments. In particular, the mobile network scenario 100 includes a mobile network 102 that supports one or more UEs 104.

The mobile network 102 is an example of a standardized network deployment that supports both evolved packet core (EPC) and 5GC protocols. The mobile network 102 includes a combined home subscriber server (HSS) and unified data management (UDM) 106 (which may be referred to as a "UDM"). The combined HSS and UDM 106 stores information related to user subscriptions. For example, the combined HSS and UDM 106 stores information regarding which radio access technology (RAT), radio access network (RAN), tracking area, location area, and/or other network services a UE associated with a user may utilize based on a user subscription for the user. Accordingly, the mobile network 102 may limit access to network services to users with subscriptions to those network services.

The mobile network 102 further includes an EPC 108. The EPC 108 is coupled to the combined HSS and UDM 106. The EPC 108 supports EPC protocol. Accordingly, the

EPC 108 supports UEs operating with EPC protocol. The EPC 108 may retrieve information related to user subscriptions for UEs that establish a radio resource control

(RRC) connection with the EPC 108.

The mobile network 102 further includes a 5GC 110, which may also be referred to as a next generation core (NGC) or a new generation core (NGC). The 5GC 110 is coupled to the combined HSS and UDM 106. The 5GC 110 supports 5GC protocol.

Accordingly, the 5GC 110 supports UEs operating with the EPC protocol. The 5GC 110 may retrieve information related to user subscriptions for UEs that establish an RRC connection with the 5GC 110. The mobile network 102 further includes one or more access points 112. In the illustrated embodiment, the mobile network includes a first evolved universal mobile telecommunication system terrestrial radio access network (E-UTRAN) access point 112a, a second E-UTRAN access point 112b, and a new radio (NR) access point 112c. In some embodiments, the first E-UTRAN access point 112a and the second E-UTRAN access point 112b may comprise evolved NodeBs (eNBs), and the NR access point 112c may comprise a next generation NodeB (gNB).

The first E-UTRAN access point 112a is coupled to the EPC 108. In particular, the first E-UTRAN access point 112a is coupled to the EPC 108 via an SI interface 114. The SI interface 114 provides for communication between the first E-UTRAN access point 112a and the EPC 108. Further, the first E-UTRAN access point 112a generates an E- UTRAN cell. The first E-UTRAN access point 112a can broadcast within the E-UTRAN cell an indication that the first E-UTRAN access point 112a is connected to the EPC 108 and/or that the first E-UTRAN access point 112a supports EPC protocol. UEs within the E-UTRAN cell may connect to the first E-UTRAN access point 112a and communicate with the EPC 108 via EPC protocol.

The second E-UTRAN access point 112b is coupled to both the EPC 108 and the 5GC 110. In particular, the second E-UTRAN access point 112b is coupled to the EPC 108 via an SI interface 116, and is coupled to the 5GC 110 via an N2/N3 interface 118. The SI interface 116 provides for communication between the second E-UTRAN access point 112b and the EPC 108. Further, the N2/N3 interface 118 provides for

communication between the second E-UTRAN access point 112b and the 5GC 110. The second E-UTRAN 112b generates an E-UTRAN cell. The second E-UTRAN access point 112b can broadcast within the E-UTRAN cell an indication that the second E-UTRAN access point 112b is connected to the EPC 108 and the 5GC 110, and/or that the second E- UTRAN access point 112b supports EPC protocol and 5GC protocol. UEs within the E- UTRAN cell may connect to the second E-UTRAN access point 112, and communicate with the EPC 108 via EPC protocol and/or the 5GC 110 via 5GC protocol.

The NR access point 112c is coupled to the 5GC 110. In particular, the NR access point 112c is coupled to the 5GC 110 via an N2/N3 interface 120. The N2/N3 interface 120 provides for communication between the NR access point 112c and the 5GC 110. The NR access point 112c generates an NR cell. The NR access point 112c can broadcast within the NR cell an indication that the NR access point 112c is connected to the 5GC 110 and/or that the NR access point 112c supports 5GC protocol. UEs within the NR cell may connect to the NR access point 112c and communicate with the 5GC 110 via 5GC protocol.

The second E-UTRAN access point 112b and the NR access point 112c are further coupled to each other. In particular, the second E-UTRAN access point 112b and the NR access point 112c are being operated in non-stand alone (NSA), dual connectivity (DC) configuration, whereas the first E-UTRAN access point 112a is being operated in standalone (SA) configuration. The second E-UTRAN access point 112b and the NR access point 112c being coupled provides for DC with the second E-UTRAN access point 112b and the NR access point 112c. When access points are operated in a DC configuration, a UE can be simultaneously connected to more than one access point that is operating in the DC configuration. For example, the second E-UTRAN access point 112b and the NR access point 112c are configured in NSA, DC configuration. Accordingly, a UE can be simultaneously connected to the second E-UTRAN access point 112b and the NR access point 112c, and can send and receive data and signaling via the second E-UTRAN access point 112b and the NR access point 112c simultaneously. The second E-UTRAN access point 112b is coupled via the SI interface 116 to the EPC and has the NR access point 112c in DC configuration via interface 122. The second E-UTRAN access point 112b is further coupled via the N2/N3 interface 118 to the 5GC 110 and has the NR access point 112c in DC configuration via interface 124. The NR access point 112c is coupled via the N2/N3 interface 120 to the 5 GC 110 and has the second E-UTRAN access point 112b in DC configuration via interface 126.

The UEs 104 of the mobile network scenario 100 include a first UE 104a, a second UE 104b, a third UE 104c, and a fourth UE 104d. Each of the UEs 104 have different capabilities that affect which of the access points 112 and/or which of the EPC 108 and 5GC 110 are connected. Further, each of the UEs 104 may perform different procedures depending on which of the EPC 108 and the 5GC 110 the UE connects.

The first UE 104a has only EPC non-access stratum (NAS) capability.

Accordingly, the first UE 104a may connect only to the EPC 108. Further, the first UE 104a does not support DC and/or is configured in SA configuration. Therefore, the first UE 104a can connect only to the EPC 108. For example, the first UE 104a is connected to the EPC 108 via the second E-UTRAN access point 112b, as illustrated by line 128, in the illustrated embodiment. The first UE 104a utilizes EPC NAS procedures and EPC protocols to communicate with the EPC 108. The second UE 104b has only EPC NAS capability. Accordingly, the second UE 104b may connect only to the EPC 108. Further, the second UE 104b supports DC and/or is configured in DC configuration. Therefore, the second UE 104b can connect only to the EPC 108, although it can connect to the EPC 108 via one or more access points 112. For example, the second UE 104b is connected to the EPC 108 via the first E-UTRAN access point 112a, as illustrated by line 130, and via the second E-UTRAN access point 112b, as illustrated by line 132, in the illustrated embodiment. The second UE 104b utilizes EPC NAS procedures and EPC protocols to communicate with the EPC 108. Due to the dual connectivity, the second UE 104b can simultaneously communicate with the EPC 108 via the first E-UTRAN access point 112a and the second E-UTRAN access point 112b.

The third UE 104c has both EPC NAS capability and 5GC NAS capability.

Therefore, the third UE 104c may connect to either of the EPC 108 or the 5GC 110. The third UE 104c will attempt to connect to the highest quality network available, which would involve connecting to the 5GC 110 in the illustrated embodiment. The third UE 104c can be connected to 5GC 110 via the second E-UTRAN access point 112b or the NR access point 112c. The third UE 104c is connected to the 5GC 110 via the second E- UTRAN access point 112b, as illustrated via line 134 in the illustrated embodiment. The third UE 104c utilizes 5GC NAS procedures and 5GC protocols to communicate with the 5GC 110.

The fourth UE 104d has both EPC NAS capability and 5GC NAS capability.

Therefore, the fourth UE 104d may connect to either of the EPC 108 or the 5GC 110. The fourth UE 104d will attempt to connect to the network providing the best possible service, which would involve connecting to the 5GC 110 in the illustrated embodiment. The fourth UE 104d can be connected to 5GC 110 via the second E-UTRAN access point 112b or the NR access point 112c. The fourth UE 104d is connected to the 5GC 110 via the NR access point 112c, as illustrated via line 136 in the illustrated embodiment. The fourth UE 104d utilizes 5GC NAS procedures and 5GC protocols to communicate with the 5GC 110.

While the UEs 104 are connected in the illustrated embodiment, the arrangement of the mobile network 102 may present a complication with the second E-UTRAN 112b. In particular, the EPC 108 and the 5GC 110 access the combined HSS and UDM 106 to determine whether a UE is allowed to connect to the EPC 108 and the 5GC based on user data associated with the UE. The EPC 108 and the 5GC 110 utilize the user data associated with the UE to determine a user subscription for a user of the UE. The user subscription may prevent the UE from connecting and/or registering with the EPC 108 and/or the 5GC 110. In instances where the subscription prevents the UE from connecting and/or registering with the EPC 108 and/or the 5GC 110, the access point (such as the access points 112) to which the UE was utilizing to attempt to connect and/or register with the EPC 108 and/or the 5GC 110 would transmit a registration reject message to the UE. Utilizing some legacy protocols, the registration reject message would indicate that use of a certain type of access point is not allowed by the UE. For example, the registration reject message would indicate that E-UTRAN is not allowed or NR is not allowed based on the type of access point that the UE was utilizing. Utilizing other legacy protocols, the registration reject message would indicate that use of the specific access point is not allowed by the UE. For example, the registration reject message would indicate that the UE was not allowed to use a tracking area, where the tracking area corresponds to the specific access point.

Considering the arrangement of the mobile network scenario 100, the complication may result from the third UE 104c attempting to connect to the mobile network 102. In particular, the third UE 104c could attempt to connect to the 5GC 110 via the second E- UTRAN access point 112b. If the 5GC 110 determined that the third UE 104c was not allowed to register to the 5GC 110 based on the subscription information associated with the third UE 104c stored in the combined HSS and UDM 106, the 5 GC 110 would cause the second E-UTRAN access point 112b to transmit a registration reject message to the third UE 104c.

In instances where the legacy protocols have the registration reject message indicating that use of a certain type of access point is not allowed by the third UE 104c, the second E-UTRAN access point 112b would transmit a registration reject message indicating that the third UE 104c was not allowed to connect to E-UTRAN access points. In response to receiving the registration reject message, the third UE 104c would avoid trying to connect via E-UTRAN access points, including the first E-UTRAN access point 112a and the second E-UTRAN access point 112b. This is undesirable for the mobile network 102 as the third UE 104c would be prevented from connecting with the 5GC 110 by the subscription limitation and would be prevented from connecting with the EPC 108 as only E-UTRAN access points provide connectivity with the EPC 108.

In instances where the legacy protocols have the registration reject message indicating that use of the specific access point is not allowed by the third UE 104c, the second E-UTRAN access point 112b would transmit a registration reject message indicating that the third UE 104c was not allowed to connect to the second E-UTRAN 112b. In response to receiving the registration reject message, the third UE 104c would avoid trying to connect via the second E-UTRAN access point 112b. This is undesirable for the mobile network 102 as the second E-UTRAN access point 112b could still provide connectivity to the EPC 108 for the third UE 104c, which attempting to connect to a different access point may not be available due to proximity of other access points to the third UE 104c. Further, the third UE 104c may continue to attempt to connect to the 5GC 110 through other access points as the registration reject message indicating that only a specific access point was not allowable.

The mobile network 102 herein implements a protocol where the registration reject message indicates that Nl mode is not allowed, where Nl mode includes connecting to the 5GC 110 via Nl interface, indicated by line 134 and line 136. In particular, the third UE 104c could request connection and/or registration with the 5GC 110 via the second E- UTRAN access point 112b. The 5GC 110 may determine that the third UE 104c is not allowed to connect and/or register with the 5GC 110 based on subscription information associated with the third UE 104c stored in the combined HSS and UDM 106. In response to the 5GC 110 determining the third UE 104c is not allowed to connect and/or register with the 5GC 110, the 5GC 110 causes the second E-UTRAN access point 112b to transmit the rejection reject message that indicates that Nl mode is not allowed to the third UE 104c. The third UE 104c disables its Nl mode radio capability based on the indication. With the Nl mode radio capability disabled, the third UE 104c attempts to connect to access points 112 that indicate the access point is connected to the EPC 108 and/or support EPC protocol, omits an Nl capability indication from attempts to register, or some combination thereof. Accordingly, the third UE 104c may still utilize the first E- UTRAN access point 112a and the second E-UTRAN access point 112b to connect to the EPC 108. In other embodiments, the registration reject message may indicate that 5GC is not allowed.

In some embodiments, the third UE 104c can identify a public land mobile (PLMN) identity (ID) or a tracking area ID (TAI) associated with the registration reject message. The PLMN ID and the TAI may be associated with the access point (such as the access points 112) or the cell provided by the access point. In embodiments where the third UE 104c identifies the PLMN ID, the third UE 104c stores the PLMN ID in a list of PLMNs where Nl mode is not allowed. In embodiments where the third UE 104c identifies the TAI, the third UE 104c stores the TAI in a list of TAIs where Nl mode is not allowed. For example, the a UE NAS of the third UE 104c may store the PLMN ID or the TAI in the list of PLMNs where Nl mode is not allowed or the list of TAIs where Nl is not allowed, respectively. The list of PLMNs or the list of TAIs may be stored in the third UE 104c or on a universal subscriber identity module (USIM). The list may be forwarded internally to an access stratum (AS) of the third UE 104c so the AS can use the list, such as to determine whether a cell (either an E-UTRAN cell or an NR cell) is suitable for camping.

Further, in some embodiments, the third UE 104c can delete the IDs within the list of PLMNs where Nl mode is not allowed or the IDs within the list of TAIs where Nl mode is not allowed. For example, the IDs within either of the lists can be deleted when the UE is switched off or an expiration of a time interval. The time interval can be fixed, chosen randomly from certain intervals (such as between 12 hours and 24 hours), or signalled by the mobile network 102.

Figure 2 illustrates an example network architecture 200, according to various embodiments. The network architecture 200 supports NR (otherwise referred to as 5G system (5GS)), EPC/E-UTRAN, and global system for mobile communications/enhanced data rates for global system for mobile communications evolution radio access network (GERAN)/universal mobile telecommunication system terrestrial radio access network (UTRAN). In particular, the network architecture 200 illustrates an embodiment of a non- roaming architecture for interworking between NR and EPC/E-UTRAN and between EPC/E-UTRAN and GERAN/UTRAN.

The network architecture 200 includes an HSS 202. The HSS 202 supports the GERAN/UTRAN and EPC/E-UTRAN portions of the network architecture 200. The HSS 202 may have been implemented with the GERAN/UTRAN and EPC/E-UTRAN portions of the network architecture 200 prior to introduction of the NR into the network architecture 200. The HSS 202 stores user subscription information for the

GERAN/UTRAN and EPC/E-UTRAN portions of the network architecture 200. The HSS 202 may store user subscription information that was generated and/or stored prior to the implementation of the NR into the network. Further, the HSS 202 may store user subscription information for the GERAN/UTRAN and EPC/E-UTRAN portions of the network that was generated and/or stored after the implementation of the NR network.

The network architecture 200 includes a first packet data network (PDN) 204. The first PDN 204 supports the GERAN/UTRAN and EPC/E-UTRAN portions of the network architecture 200. The first PDN 204 may provide connectivity for the GERAN/UTRAN and EPC/E-UTRAN portions of the network architecture 200 to other packet data networks, such as the internet and session initiation protocol (SlP)-based internet protocol (IP) multimedia subsystems (IMS).

The network architecture 200 includes a PDN gateway (PGW) 206. The PGW 206 is coupled to the first PDN 204. The PGW 206 acts as an interface between the first PDN 204 and the GERAN/UTRAN and EPC/E-UTRAN portions of the network architecture 200. The PGW 206 can receive requests for connection to the first PDN 204 from UEs and allocate IP addresses to the UEs. In particular, the PGW 206 can receive requests for connection to the first PDN 204 from UEs operating within the GERAN/UTRAN and/or EPC/E-UTRAN.

The network architecture 200 includes a serving gateway (SGW) 208. The SGW

208 is coupled to the first PGW 206. The SGW 208 acts as an interface to the first PGW 206. The SGW 208 manages packet routing for the first PGW 206. Further, the SGW 208 manages handover among access points of the GERAN/UTRAN and/or EPC/E-UTRAN portions of the network architecture 200.

The network architecture 200 includes a combined UDM and HSS 210. The combined UDM and HSS 210 supports the EPC/E-UTRAN and the NR portions of the network architecture 200. The combined UDM and HSS may have been implemented with the NR portion of the network architecture 200, which may have occurred after implementation of the GERAN/UTRAN and/or EPC/E-UTRAN portions of the network architecture 200. The combined UDM and HSS 210 stores user subscription information for the EPC/E-UTRAN portions of the network architecture 200. Due to the later implementation of the combined UDM and HSS 210, a network operator may initially configure the combined UDM and HSS 210 with user subscription information for users that are subscribed to NR (i.e., can utilize 5GS) via the combined UDM and HSS 210. Accordingly, the combined UDM and HSS 210 may lack user subscription information for users that can access the GERAN/UTRAN and EPC/E-UTRAN, but are not subscribed to NR.

The network architecture 200 includes a second PDN 212. The second PDN 212 can support the GERAN/UTRAN, EPC/E-UTRAN, and NR portions of the network architecture 200. The second PDN 212 may provide connectivity for the

GERAN/UTRAN, EPC/E-UTRAN, and NR portions of the network architecture 200 to other packet data networks, such as the internet and SIP-based IMS.

The network architecture 200 includes a session management function

(SMF)/control plane PGW (PGW-C) 214 (which may be referred to as an "SMF"). The SMF/PGW-C 214 is coupled to the combined UDM and HSS 210. The SMF/PGW-C 214 can receive requests for connection to the second PDN 212 from UEs and allocate IP addresses to the UEs. In particular, the SMF 214 can receive requests for connection to the second PDN 212 from UEs operating within the GERAN/UTRAN, EPC/E-UTRAN, and/or NR portions of the network architecture 200.

The network architecture 200 includes a user plane function (UPF)/user plane PGW (PGW-U) 216 (which may be referred to as a "UPF"). The UPF/PGW-U 216 is coupled to the second PDN 212 and the SMF/PGW-C 214. The UPF/PGW-U 216 manages packet routing for the second PDN 212. Further, the UPF/PGW-U 216 manages handover among access points of the GERAN/UTRAN, EPC/E-UTRAN, and NR portions of the network architecture 200.

The network architecture 200 includes a serving general packet radio service support node (SGSN) 218. The SGSN 218 is part of the GERAN/UTRAN portion of the network architecture 200 and supports GERAN/UTRAN service. The SGSN 218 is coupled to the HSS 202 and the SGW 208. The SGSN 218 may handle packet switched data within the GERAN/UTRAN, such as mobility management and authentication of users of the GERAN/UTRAN.

The network architecture 200 includes a GERAN/UTRAN access point 220. The GERAN/UTRAN access point 220 is coupled to the SGSN 218. The GERAN/UTRAN access point 220 provides access to the GERAN/UTRAN for UEs. The GERAN/UTRAN access point 220 may comprise a nodeB.

The network architecture 200 includes a mobility management entity (MME) 222. The MME 222 is part of the EPC/E-UTRAN portion of the network architecture 200 and supports EPC/E-UTRAN service. The MME 222 is coupled to the HSS 202, the combined UDM and HSS 210, and the SGW 208. The MME 222, the SGW 208, the

PGW 206, and/or the HSS 202 may be part of an EPC (such as the EPC 108 (Fig. 1)). The MME 222 may handle packet switch data within the EPC/E-UTRAN, such as mobility management and authentication of users of the EPC/E-UTRAN.

The network architecture 200 includes an E-UTRAN access point 224. The E- UTRAN access 224 is coupled to the MME 222 and the SGW 208. The E-UTRAN access point 224 provides access to the EPC/E-UTRAN for UEs. The E-UTRAN access point 224 may comprise an eNB.

The network architecture 200 includes an access and mobility management function (AMF) 226. The AMF 226 is part of the NR portion of the network architecture 200 and supports NR service. The AMF 226 is coupled to the combined UDM and HSS 210 and the SMF/PGW-C 214. The AMF 226, the UPF/PGW-U 216, the SMF/PGW-C 214, and/or the combined UDM and HSS 210 may be part of a 5GC (such as the 5GC 110 (Fig. 1)). The AMF 226 may perform registration management, connection management, mobility management, and access authentication and authorization for the NR.

The network architecture 200 includes an NR access point 228 (which may be referred to as a "5G RAN access point"). The NR access point 228 is coupled to the UPF/PGW-U 216 and the AMF 226. The NR access point 228 provides access to the NR for UEs. The NR access point 228 may comprise a gNB.

The network architecture 200 includes one or more UEs 230. The network architecture 200 includes a first UE 230a, a second UE 230b, and a third UE 230c in the illustrated embodiment. The first UE 230a is illustrated connected to the

GERAN/UTRAN access point 220 and accessing the GERAN/UTRAN. The second UE 230b is illustrated connected to the E-UTRAN access point 224 and accessing the EPC/E- UTRAN. The third UE 230c is illustrated connected to the NR access point 228 and accessing the NR. While the UEs 230 are illustrated connected to certain access points and RANs, it should be understood that the UEs 230 can change connections to other access points and other RANs. For example, the first UE 230a that is connected to the GERAN/UTRAN access point 220 may transfer to connecting to the E-UTRAN access point 224 and/or the NR access point 228, and access the EPC/E-UTRAN and/or NR, respectively, at different times.

Interfaces between the SGSN 218 and the MME 222, and between the MME 222 and the AMF 226 can facilitate handover of the UEs 230 from one of the networks to another of the networks. For example, an interface 232 (which may be referred to as an S3 interface) between the SGSN 218 and the MME 222 may facilitate handover of the UEs between the GERAN/UTRAN and the EPC/E-UTRAN. Further, an interface 234 (which may be referred to as an N26 interface) may facilitate handover of the UEs between the EPC/E-UTRAN and the NR. The interfaces may support transfer of UE context and PDN connections between the SGSN 218 and the MME 222, and between the MME 222 and the AMF 226. The interfaces may provide for easier transfer of the UE context and the PDN connections, with fewer interruptions, between the SGSN 218 and the MME 222, and between the MME 222 and the AMF 226 than if the interfaces were not present. The transfer of the UE context via the interfaces may be faster than a re-attach procedure to establish new PDN connections. Further, UEs that utilize the interfaces for transfer between networks can keep an IP address associated with a PDN connection when transferring between the networks, which enables seamless service continuity for UEs and/or applications operating on the UE utilizing PDN connections. However, it is to be noted that an interface that directly couples the SGSN 218 and the AMF 226 does not exist.

A standard configuration of a UE may include the UE trying to connect to the network configuration providing the best possible service, which would involve connecting to the NR via the AMF 226 in the network architecture 200. However, this may not be optimal in some instances with the network architecture 200. For example, the first UE 230a transferring connection from the SGSN 218 to the AMF 226 would not be optimal. In particular, because there is not an interface that directly couples the SGSN 218 and the AMF 226, it may not be possible to transfer UE context associated with the first UE 230a between the SGSN 218 and the AMF 226. Due to the last transfer of UE context, the first UE 230a would need to perform a new attach procedure with the AMF 226 and establish PDN connections anew. Further, the first UE 230a may be assigned a new IP address when transferring connection between the SGSN 218 and the AMF 226 depending on the network configuration of the GERAN/UTRAN and/or the NR.

Performance of the new attach procedure, establishing the PDN connections anew, and/or being assigned the new IP address may result in service discontinuity, which would be undesirable. Accordingly, it would be preferable for the first UE 230a to limit connection transfer to the MME 222 when service discontinuity would disrupt proper operation of the first UE 230a, such that the first UE 230a may utilize the interface 232 and avoid, or at least limit, service discontinuity.

In some embodiments, an operator of a network may decide to establish PDN connections activated via the GERAN/UTRAN via the PGW 206, and to establish a PDN connection via the UPF/PGW-U 216 if connection is activated via the E-UTRAN access point 224 and the user associated with the UE has a subscription for the NR. The operator may implement this due to the resources of the UPF/PGW-U 216 being limited, and therefore may want to reserve the resources for UEs able and allowed to use the NR. For example, the UPF/PGW-U 216 may have limited memory, number of IP addresses, user plane bandwidth, and/or signalling processing power. Each of the PGW 206 and each of the UPF/PGW-U 216 are assigned a separate value range of IP addresses, so it may not be possible to keep the IP address if the end point of the PDN connection is moved between the PGW 206 and the UPF/PGW-U 216. Trying to connect to the NR may also not be optimal in instances where subscription information for a user associated with a UE attempting to connect to the AMF 226 is not stored on the combined UDM and HSS 210. This may occur when a network operator has yet to update the combined UDM and HSS 210 with the subscription information for the user. In particular, the AMF 226 attempts to retrieve subscription information associated with a UE from the combined UDM and HSS 210 in response to an RRC connection setup complete message from the UE. In the instance where the combined UDM and HSS 210 does not have the subscription information stored for the UE, the AMF 226 is unable to retrieve the subscription information from combined UDM and HSS 210. Further, the AMF 226 does not have a direct interface defined between the AMF 226 and the HSS 202, and will not be able to retrieve subscription data. For such a user without subscription information stored on the combined UDM and HSS 210, an RRC connection setup complete message from the UE associated with the user could be routed to the combined UDM and HSS 210, which would not be able to find the subscription information and could respond with an error cause indicating that the user does not have a subscription for NR services. The AMF could generate a registration reject message with a suitable mobility management (MM) cause that prevents the UE from re-attempting the registration to the AMF 226 in response to receiving the error cause from the combined UDM and HSS 210.

To address these instances where attempting to connect to the NR is not optimal, the UE may be configured to prioritize registration to EPC/E-UTRAN over registration to NR. For example, for a UE supporting GERAN, UTRAN, or both GERAN and UTRAN in addition to NR, the UE may change priorities between registration to EPC/E-UTRAN and registration to NR based on the UE receiving a reject cause indicating NR is not allowed when attempting to register to a network via NR. For example, if a UE is camping on E-UTRAN and the E-UTRAN access point 224 indicates to the UE that the E- UTRAN access point 224 offers connections both to an EPC (such as the EPC 108 (Fig. 1)) and a 5GC (such as the 5GC 110 (Fig. 1)), the UE may prefer registration to the EPC. Further, when the UE performs cell re-selection and finds E-UTRAN cells offering connection only to a 5GC and other cells offering connection to an EPC, the UE prefers reselection to the cell offering connection to the EPC.

Figure 3 illustrates a message flow of an example registration request procedure 300, according to various embodiments. In particular, Figure 3 illustrates signal flow among a UE 302 (such as the UEs 104 (Fig. 1) and/or the UEs 230 (Fig. 2)), an E-UTRAN access point 304 (such as the second E-UTRAN access point 112b (Fig. 1) and/or the E- UTRAN access point 224 (Fig. 2)), an AMF 306 (such as the AMF 226 (Fig. 2)), and an MME 308 (such as the MME 222 (Fig. 2)). The E-UTRAN access point 304 can provide connections to both the AMF 306 and the MME 308 in the illustrated embodiment. The example registration request procedure 300 illustrates an unsuccessful registration with a 5GC.

The UE 302 is initially camping on an E-UTRAN cell and listening to system information broadcast from the E-UTRAN access point 304. In particular, the E-UTRAN access point 304 generates and broadcasts a system information signal 310 that is received by the UE 302. The system information signal 310 indicates that the E-UTRAN access point 304 offers a connection to 5GC and to EPC. In particular, the system information signal 310 can include "N1/5GC supported" to indicate that the E-UTRAN access point 304 offers connection to 5GC and "Sl/EPC supported" to indicate that the E-UTRAN access point 304 offers connection to EPC. In other embodiments, the indication of EPC could be given implicitly, such as the UE 302 would assume that EPC is supported and the E-UTRAN access point 304 would only explicitly indicate when EPC is not supported.

The UE 302 establishes an RRC connection with the E-UTRAN access point 304. In particular, the UE 302 generates and transmits an RRC connection request message 312 to the E-UTRAN access point 304 and the E-UTRAN access point 304 responds with an RRC connection setup message 314. The UE 302 generates and transmits an RRC connection setup complete message 316 to the E-UTRAN access point 304 in response to identifying the RRC connection setup message 314. The RRC connection setup complete message 316 includes an indication that the UE 302 supports Nl interface, such as by including "Nl capability" in the RRC connection setup complete message 316.

Additionally, the RRC connection setup complete message 316 includes the 5GC NAS message "Registration Request."

The E-UTRAN access point 304 identifies the RRC connection setup complete message 316 with the 5GC NAS message "Registration Request." The E-UTRAN access point 304 determines from the indication that the UE 302 supports the Nl interface that is included in the RRC connection setup complete message 316 that the UE 302 wants to establish a connection with a 5GC (such as the 5GC 110 (Fig. 1)). The E-UTRAN access point 304 selects the AMF 306, and generates and transmits an N2AP initial UE message 318 to the AMF 306. The N2AP initial UE message 318 includes the 5GC NAS

"Registration Request." The AMF 306 retrieves subscription information associated with the UE 302 from a combined UDM and HSS (such as the combined UDM and HSS 106 (Fig. 1) and/or the combined UDM and HSS 210 (Fig. 2)). The AMF 306 determines that the UE 302 does not have a subscription for NR based on the subscription information. Therefore, the AMF 306 decides to reject the registration request. The AMF 306 generates and transmits an N2AP downlink NAS transport message 320 to the E-UTRAN access point 304. The N2AP downlink NAS transport message 320 includes an MM cause that indicates that Nl mode is not allowed based on the AMF 306 deciding to reject the registration request.

The E-UTRAN access point 304 identifies the N2AP downlink NAS transport message 320 received from the AMF 306. The E-UTRAN access point 304 forwards the registration reject from the N2AP downlink NAS transport message 320 to the UE 302 in an RRC downlink information transfer message 322. The registration reject includes the MM cause that indicates that Nl is not allowed. In some embodiments, the E-UTRAN access point 304 determines that the registration request is not accepted by the 5GC via routing the "Registration Request" to the AMF 306 and identifying the registration reject in the N2AP downlink NAS transport message 320.

An N2 connection and the RRC connection are released after transmission of the RRC downlink information transfer message 322. Releasing the N2 connection and the RRC connection may involve performance of a release procedure. The AMF 306 initiates the release procedure by generating and transmitting an N2AP context release command message 324 to the E-UTRAN access point 304. The E-UTRAN access point 304 identifies the N2AP context release command message 324, and generates and transmits an RRC connection release message 326 in response to identifying the N2AP context release message 324. Further, the E-UTRAN access point 304 generates and transmits an N2AP UE context release complete message 328 to the AMF 306 to complete the release procedure.

The UE 302 disables Nl mode via a disable procedure 330 in response to identifying the indication that Nl mode is not allowed in the RRC downlink information transfer message 322. In some embodiments, the UE 302 may disable the Nl mode upon receipt of the registration reject with the MM cause that Nl mode is not allowed. With the Nl mode disabled, the UE stays in the current PLMN and does not attempt to connect to the AMF 306 (i.e., does not attempt to initiate any 5GC NAS procedures). Further, the UE 302 will not include an Nl capability indication in RRC messages when it requests establishment or re-establishment of an RRC connection while Nl mode is disabled. Further, the NAS will inform AS that the use of Nl is not allowed in the PLMN corresponding to the E-UTRAN access point 304. Accordingly, the AS will consider E- UTRAN cells for which the E-UTRAN access point 304 indicates that it can only offer a connection to a 5GC as not "suitable" for camping. Further, when AS decides to camp on a cell offering both a connection to a 5GC and a connection to an EPC, the AS will indicate to NAS only the ability to connect to an EPC.

In response to identifying the indication that Nl mode is not allowed in the RRC downlink information transfer message 322, the UE 302 may initiate a registration procedure (such as an attach procedure or a tracking area update (TAU) procedure) to the EPC. In particular, the UE 302 may initiate the registration procedure since the E- UTRAN access point 304 offers a connection to the EPC via the MME 308. In embodiments where the E-UTRAN access point 304 does not offer connection to the EPC, the UE 302 will perform cell selection to attempt to select another cell (which may be potentially on another RAT).

The UE 302 initiates the registration procedure by generating and transmitting another RRC connection request message 332 to the E-UTRAN access point 304. The UE 302 generates and transmits the RRC connection request message 332 in an attempt to register with the EPC via the MME 308. The E-UTRAN access point 304 identifies the RRC connection request message 332, and generates and transmits an RRC connection setup message 334 in response to identification of the RRC connection request message 332. The UE 302 identifies the RRC connection setup message 334. In response to identification of the RRC connection setup message 334, the UE 302 generates and transmits an RRC connection setup complete message 336 to the E-UTRAN access point 304. The RRC connection setup complete message 336 includes an EPC NAS attach request for registration with the EPC via the MME 308. The Nl capability indication is omitted from the RRC connection setup complete message 336. The Nl capability indication may be omitted based on the disablement of Nl capability by the UE 302 that occurred during the disable procedure 330. In other embodiments where the UE is already registered to the EPC, the RRC connection setup complete message 336 can include an EPC NAS TAU request message.

The E-UTRAN access point 304 may identify the RRC connection setup complete message 336 received from the UE 302. The E-UTRAN access point 304 determines that the Nl capability indication is absent from the RRC connection setup complete message 336. Accordingly, the E-UTRAN access point 304 determines that the UE 302 wants to establish a connection with an EPC via the MME 308 based on the absence of the Nl capability indication. Based on the determination that the UE 302 wants to establish the connection with an EPC, the E-UTRAN access point 304 generates and transmits an SIAP initial UE message 338 to the MME 308. The SIAP initial UE message 338 includes the EPC NAS attach request from the RRC connection setup complete message 336.

The MME 308 identifies the SIAP initial UE message 338. In response to the identification of the SIAP initial UE message 338, the MME 308 retrieves subscription information associated with the UE 302 from an HSS (such as the HSS 202 (Fig. 2)). The MME 308 determines that the UE 302 has a subscription for EPC based on the subscription information. Therefore, the MME 308 decides to grant the registration request. The MME 308 generates and transmits an SIAP downlink NAS transport message 340 to the E-UTRAN access point 304. The SIAP downlink NAS transport message 340 includes an EPC NAS attach accept.

The E-UTRAN access point 304 identifies the SIAP downlink NAS transport message 340 received from the MME 308. The E-UTRAN access point 304 forwards the EPC NAS attach accept to the UE 302 in an RRC downlink information transfer message 342. In some embodiments, the E-UTRAN access point 304 determines that the registration request is accepted by the EPC via routing the EPC NAS attach request to the MME 308 and identifying the EPC NAS attach accept in the SIAP downlink NAS transport message 340.

Figure 4 illustrates a message flow of an example registration request procedure 400, according to various embodiments. In particular, Figure 4 illustrates signal flow among a UE 402 (such as the UEs 104 (Fig. 1) and/or the UEs 230 (Fig. 2)), an E-UTRAN access point 404 (such as the second E-UTRAN access point 112b (Fig. 1) and/or the E- UTRAN access point 224 (Fig. 2)), an AMF 406 (such as the AMF 226 (Fig. 2)), and an MME 408 (such as the MME 222 (Fig. 2)). The E-UTRAN access point 404 can provide connections to both the AMF 406 and the MME 408 in the illustrated embodiment. The example registration request procedure 400 illustrates a successful registration with a 5GC.

The UE 402 is initially camping on an E-UTRAN cell and listening to system information broadcast from the E-UTRAN access point 404. In particular, the E-UTRAN access point 404 generates and broadcasts a system information signal 410 that is received by the UE 402. The system information signal 410 indicates that the E-UTRAN access point 404 offers a connection to 5GC and to EPC. In particular, the system information signal 410 can include "N1/5GC supported" to indicate that the E-UTRAN access point 404 offers connection to 5GC and "Sl/EPC supported" to indicate that the E-UTRAN access point 404 offers connection to EPC. In other embodiments, the indication of EPC could be given implicitly, such as the UE 402 would assume that EPC is supported and the E-UTRAN access point 404 would only explicitly indicate when EPC is not supported.

The UE 402 establishes an RRC connection with the E-UTRAN access point 404. In particular, the UE 402 generates and transmits an RRC connection request message 412 to the E-UTRAN access point 404 and the E-UTRAN access point 404 responds with an RRC connection setup message 414. The UE 402 generates and transmits an RRC connection setup complete message 416 to the E-UTRAN access point 404 in response to identifying the RRC connection setup message 414. The RRC connection setup complete message 416 includes an indication that the UE 402 supports Nl interface, such as by including "Nl capability" in the RRC connection setup complete message 416.

Additionally, the RRC connection setup complete message 416 includes the 5GC NAS message "Registration Request."

The E-UTRAN access point 404 identifies the RRC connection setup complete message 416 with the 5GC NAS message "Registration Request." The E-UTRAN access point 404 determines from the indication that the UE 402 supports the Nl interface that is included in the RRC connection setup complete message 416 that the UE 402 wants to establish a connection with a 5GC (such as the 5GC 110 (Fig. 1)). The E-UTRAN access point 404 selects the AMF 406, and generates and transmits an N2AP initial UE message 418 to the AMF 406. The N2AP initial UE message 418 includes the 5GC NAS

"Registration Request."

The AMF 406 retrieves subscription information associated with the UE 302 from a combined UDM and HSS (such as the combined UDM and HSS 106 (Fig. 1) and/or the combined UDM and HSS 210 (Fig. 2)). The AMF 406 determines that the UE 402 has a subscription for NR based on the subscription information. Therefore, the AMF 406 decides to accept the registration request. The AMF 406 generates and transmits an N2AP downlink NAS transport message 420 to the E-UTRAN access point 404. The N2AP downlink NAS transport message 420 includes a 5GC NAS registration accept.

The E-UTRAN access point 404 identifies the N2AP downlink NAS transport message 420 received from the AMF 406. The E-UTRAN access point 404 forwards the 5GC NAS registration accept to the UE 402 in an RRC downlink information transfer message 422. In some embodiments, the E-UTRAN access point 404 determines that the registration request is accepted by the 5GC via routing the 5GC NAS registration request to the MME 408 and identifying the 5GC NAS registration accept in the N2AP downlink NAS transport message 420.

Figure 5 illustrates an example connection procedure 500, according to various embodiments. The connection procedure 500 is performed by a UE (such as the UEs 104 (Fig. 1), the UEs 230 (Fig. 2), the UE 302 (Fig. 3), and/or the UE 402 (Fig. 4)).

In stage 502, the UE determines whether to attempt to connect to NR. For example, the UE may determine whether Nl radio capability has been disabled. Further, the UE may determine whether a PLMN ID or tracking area ID corresponding to an access point to which the UE would connect for NR is in a stored list of PLMN IDs where Nl is not allowed or in a stored list of tracking area IDs where Nl is not allowed. In some embodiments, the UE may determine whether attempting to connect to NR is not optimal. For example, the UE may determine that connecting to NR would involve transferring from an SGSN (such as the SGSN 218 (Fig. 2)) to an AMF (such as the AMF 226 (Fig. 2)), which would not provide for transfer of UE context, may result in assignment of a new IP address, and/or may result in service interruptions at an inconvenient time (such as during a phone call). Further, the UE may determine whether a registration reject message that was due to subscription information for the UE not being stored in a combined UDM and HSS (such as the combined UDM and HSS 210 (Fig. 2)) was previously received in some embodiments.

In stage 504, the UE configures or reconfigures network prioritization. In particular, the UE configures prioritization to prioritize connection to EPC over connection to NR when the UE determines connection to NR is not optimal. In embodiments where the UE does not determine whether connection to NR is not optimal, stage 504 may be omitted.

The procedure 500 proceeds to either stage 506 or stage 512 depending on whether the UE determines it should attempt to connect to NR. If the UE determines it should attempt to connect NR, the procedure 500 proceeds to stage 506. In stage 506, the UE attempts to connect to NR. For example, the UE performs the procedures performed by the UE in accordance with message 312 (Fig. 3) through message 316 (Fig. 3) or message 412 (Fig. 4) through message 416 (Fig. 4).

In stage 508, the UE determines whether connection is successfully established to NR. In particular, the UE determines whether the 5GC NAS registration accept or the 5GC NAS registration reject is received in an RRC downlink information transfer message (such as the RRC downlink information transfer message 322 (Fig. 3) and the RRC downlink information transfer message 422 (Fig. 4)). If the 5GC NAS registration accept is received, the procedure 500 terminates at stage 508. If the 5GC NAS registration reject is received, the UE may perform an RRC connection release, in accordance with the RRC connection release message 326. Further, if the 5GC NAS registration reject is received, the UE may identify an MM cause included in the RRC downlink information transfer message. If the MM cause is Nl mode not allowed, the procedure 500 proceeds to stage 510.

In stage 510, the UE disables Nl capability. In particular, the UE performs the disable procedure 330 (Fig. 3) to disable Nl capability.

If the UE determines that it should not connect to NR in stage 502, the procedure 500 proceeds from stage 502 or stage 504 to stage 512. Further, the procedure 500 proceeds from stage 510 to stage 512. In stage 512, the UE attempts to connect to EPC. In stage 512, the UE performs the procedures performed by the UE in accordance with message 332 (Fig. 3) through message 336 (Fig. 3).

In stage 514, the UE determines whether connection is successfully established to EPC. In particular, the UE determines whether an EPC NAS attach accept or an EPC NAS attach reject is received in an RRC downlink information transfer message (such as the RRC downlink information transfer message 342 (Fig. 3).

Figure 6 illustrates another example connection procedure 600, according to various embodiments. The connection procedure 600 is performed by an access point (such as the access points 112 (Fig. 1), the GERAN/UTRAN access point 220 (Fig. 2), the E-UTRAN access point 224 (Fig. 2), the NR access point 228 (Fig. 2), the E-UTRAN access point 304 (Fig. 3), and/or the E-UTRAN access point 404 (Fig. 4)). In some embodiments, the connection procedure 600 may be only performed by an access point that provides connection to both EPC and NR.

In stage 602, the access point performs RRC setup. In particular, the access point performs procedures to be performed by an access point in accordance with message 310 (Fig. 3) through message 316 (Fig. 3).

In stage 604, the access point determines to which network a UE (such as the UEs

104 (Fig. 1), the UEs 230 (Fig. 2), the UE 302 (Fig. 3), and/or the UE 402 (Fig. 4)) is attempting to establish a connection. In particular, the access point determines whether an RRC connection setup complete message (such as the RRC connection setup complete message 316, the RRC connection setup complete message 336 (Fig. 3), and/or the RRC connection setup complete message 416 (Fig. 4)) received from the UE includes an indication of Nl capability, a 5GC NAS registration request, and/or an EPC NAS attach request. The access point determines that the UE is attempting to establish a connection with NR if the RRC connection setup complete message includes an indication of Nl capability and/or a 5GC NAS registration request. The procedure 600 proceeds to stage 606 if the access point determines that the UE is attempting to establish a connection with NR. The access point determines that the UE is attempting to establish a connection with EPC if the RRC connection setup complete message includes an EPC NAS attach request. The procedure 600 proceeds to stage 610 if the access point determines that the UE is attempting to establish connection with EPC.

In stage 606, the access point attempts to establish a connection to NR for the UE. In particular, the access point performs procedures performed by the access point in accordance with message 318 (Fig. 3) and message 320 (Fig. 3), or message 418 (Fig. 4) and 420 (Fig. 4).

In stage 608, the access point determines whether a successful connection to NR was established. In particular, the access point determines whether an N2AP downlink NAS transport message (such as the N2AP downlink NAS transport message 320 (Fig. 3) and/or the N2AP downlink NAS transport message 420 (Fig. 4)) includes a 5GC NAS registration reject or a 5GC NAS registration accept. If the access point determines that an N2AP downlink NAS transport message includes a 5GC NAS registration reject, the access point generates and transmits an RRC downlink information transfer message (such as the RRC downlink information transfer message 322 (Fig. 3)) to the UE, where the RRC downlink information transfer message includes the forwarded 5GC NAS registration reject and MM cause indication. If the access point determines that an N2AP downlink NAS transport message includes a 5GC NAS registration accept, the access point generates and transmits an RRC downlink information transfer message (such as the RRC downlink information transfer message 422 (Fig. 4)) to the UE, where the RRC downlink information transfer message includes the forwarded 5GC NAS registration accept.

In stage 610, the access point attempts to establish a connection to EPC for the UE.

In particular, the access point performs procedures performed by the access point in accordance with message 338 (Fig. 3) and message 340 (Fig. 3).

In stage 612, the access point determines whether a successful connection to EPC was established. In particular, the access point determines whether an S 1AP downlink NAS transport message (such as the SI AP downlink NAS transport message 340 (Fig. 3)) includes an EPC NAS attach reject or an EPC NAS accept. If the access point determines that an SI AP downlink NAS transport message includes an EPC NAS attach reject, the access point generates and transmits an RRC downlink information transfer message (such as the RRC downlink information transfer message 342 (Fig. 3)) to the UE, where the RRC downlink information transfer message includes the forwarded EPC NAS attach reject and MM cause indication. If the access point determines that an S1AP downlink NAS transport message includes an EPC NAS attach accept, the access point generates and transmits an RRC downlink information transfer message to the UE, where the RRC downlink information transfer message includes the forwarded EPC NAS attach accept.

Figure 7 illustrates an architecture of a system XS00 of a network in accordance with some embodiments. The system XS00 is shown to include a user equipment (UE) XSOl and a UE XS02. The UEs XSOl and XS02 are illustrated as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks), but may also comprise any mobile or non-mobile computing device, such as Personal Data Assistants (PDAs), pagers, laptop computers, desktop computers, wireless handsets, or any computing device including a wireless communications interface.

In some embodiments, any of the UEs XSOl and XS02 can comprise an Internet of Things (IoT) UE, which can comprise a network access layer designed for low-power IoT applications utilizing short-lived UE connections. An IoT UE can utilize technologies such as machine-to-machine (M2M) or machine-type communications (MTC) for exchanging data with an MTC server or device via a public land mobile network (PLMN), Proximity -Based Service (ProSe) or device-to-device (D2D) communication, sensor networks, or IoT networks. The M2M or MTC exchange of data may be a machine- initiated exchange of data. An IoT network describes interconnecting IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived connections. The IoT UEs may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate the connections of the IoT network.

The UEs XSOl and XS02 may be configured to connect, e.g., communicatively couple, with a radio access network (RAN) XS10— the RAN XS10 may be, for example, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), aNextGen RAN (NG RAN), or some other type of RAN. The UEs XSOl and XS02 utilize connections XS03 and XS04, respectively, each of which comprises a physical communications interface or layer (discussed in further detail below); in this example, the connections XS03 and XS04 are illustrated as an air interface to enable communicative coupling, and can be consistent with cellular communications protocols, such as a Global System for Mobile Communications (GSM) protocol, a code- division multiple access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC) protocol, a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a fifth generation (5G) protocol, a New Radio (NR) protocol, and the like.

In this embodiment, the UEs XS01 and XS02 may further directly exchange communication data via a ProSe interface XS05. The ProSe interface XS05 may alternatively be referred to as a sidelink interface comprising one or more logical channels, including but not limited to a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Discovery Channel (PSDCH), and a Physical Sidelink Broadcast Channel (PSBCH).

The UE XS02 is shown to be configured to access an access point (AP) XS06 via connection XS07. The connection XS07 can comprise a local wireless connection, such as a connection consistent with any IEEE 802.11 protocol, wherein the AP XS06 would comprise a wireless fidelity (WiFi®) router. In this example, the AP XS06 is shown to be connected to the Internet without connecting to the core network of the wireless system (described in further detail below).

The RAN XS 10 can include one or more access nodes that enable the connections XS03 and XS04. These access nodes (ANs) can be referred to as base stations (BSs), NodeBs, evolved NodeBs (eNBs), next Generation NodeBs (gNB), RAN nodes, and so forth, and can comprise ground stations (e.g., terrestrial access points) or satellite stations providing coverage within a geographic area (e.g., a cell). The RAN XS 10 may include one or more RAN nodes for providing macrocells, e.g., macro RAN node XS 11, and one or more RAN nodes for providing femtocells or picocells (e.g., cells having smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells), e.g., low power (LP) RAN node XS12.

Any of the RAN nodes XS11 and XS12 can terminate the air interface protocol and can be the first point of contact for the UEs XS01 and XS02. In some embodiments, any of the RAN nodes XS11 and XS12 can fulfill various logical functions for the RAN XS 10 including, but not limited to, radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management.

In accordance with some embodiments, the UEs XS01 and XS02 can be configured to communicate using Orthogonal Frequency-Division Multiplexing (OFDM) communication signals with each other or with any of the RAN nodes XS11 and XS12 over a multicarrier communication channel in accordance with various communication techniques, such as, but not limited to, an Orthogonal Frequency-Division Multiple Access (OFDMA) communication technique (e.g., for downlink communications) or a Single Carrier Frequency Division Multiple Access (SC-FDMA) communication technique (e.g., for uplink and ProSe or sidelink communications), although the scope of the embodiments is not limited in this respect. The OFDM signals can comprise a plurality of orthogonal subcarriers.

In some embodiments, a downlink resource grid can be used for downlink transmissions from any of the RAN nodes XS11 and XS 12 to the UEs XS01 and XS02, while uplink transmissions can utilize similar techniques. The grid can be a time- frequency grid, called a resource grid or time-frequency resource grid, which is the physical resource in the downlink in each slot. Such a time-frequency plane

representation is a common practice for OFDM systems, which makes it intuitive for radio resource allocation. Each column and each row of the resource grid corresponds to one OFDM symbol and one OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to one slot in a radio frame. The smallest time-frequency unit in a resource grid is denoted as a resource element. Each resource grid comprises a number of resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block comprises a collection of resource elements; in the frequency domain, this may represent the smallest quantity of resources that currently can be allocated. There are several different physical downlink channels that are conveyed using such resource blocks.

The physical downlink shared channel (PDSCH) may carry user data and higher- layer signaling to the UEs XS01 and XS02. The physical downlink control channel (PDCCH) may carry information about the transport format and resource allocations related to the PDSCH channel, among other things. It may also inform the UEs XS01 and XS02 about the transport format, resource allocation, and H-ARQ (Hybrid Automatic Repeat Request) information related to the uplink shared channel. Typically, downlink scheduling (assigning control and shared channel resource blocks to the UEs XS01 and/or XS02 within a cell) may be performed at any of the RAN nodes XS11 and XS12 based on channel quality information fed back from any of the UEs XSOl and XS02. The downlink resource assignment information may be sent on the PDCCH used for (e.g., assigned to) each of the UEs XSOl and XS02.

The PDCCH may use control channel elements (CCEs) to convey the control information. Before being mapped to resource elements, the PDCCH complex-valued symbols may first be organized into quadruplets, which may then be permuted using a sub-block interleaver for rate matching. Each PDCCH may be transmitted using one or more of these CCEs, where each CCE may correspond to nine sets of four physical resource elements known as resource element groups (REGs). Four Quadrature Phase Shift Keying (QPSK) symbols may be mapped to each REG. The PDCCH can be transmitted using one or more CCEs, depending on the size of the downlink control information (DCI) and the channel condition. There can be four or more different PDCCH formats defined in LTE with different numbers of CCEs (e.g., aggregation level, L=l, 2, 4, or 8).

Some embodiments may use concepts for resource allocation for control channel information that are an extension of the above-described concepts. For example, some embodiments may utilize an enhanced physical downlink control channel (EPDCCH) that uses PDSCH resources for control information transmission. The EPDCCH may be transmitted using one or more enhanced control channel elements (ECCEs). Similar to above, each ECCE may correspond to nine sets of four physical resource elements known as an enhanced resource element groups (EREGs). An ECCE may have other numbers of EREGs in some situations.

The RAN XS10 is shown to be communicatively coupled to a core network (CN) XS20— via an SI interface XS13. In embodiments, the CN XS20 may be an evolved packet core (EPC) network, aNextGen Packet Core (NPC) network, or some other type of CN. In this embodiment the SI interface XS13 is split into two parts: the Sl-U interface XS14, which carries traffic data between the RAN nodes XS11 and XS12 and the serving gateway (S-GW) XS22, and the SI -mobility management entity (MME) interface XS15, which is a signaling interface between the RAN nodes XS11 and XS12 and MMEs XS21.

In this embodiment, the CN XS20 comprises the MMEs XS21, the S-GW XS22, the Packet Data Network (PDN) Gateway (P-GW) XS23, and a home subscriber server (HSS) XS24. The MMEs XS21 may be similar in function to the control plane of legacy Serving General Packet Radio Service (GPRS) Support Nodes (SGSN). The MMEs XS21 may manage mobility aspects in access such as gateway selection and tracking area list management. The HSS XS24 may comprise a database for network users, including subscription-related information to support the network entities' handling of

communication sessions. The CN XS20 may comprise one or several HSSs XS24, depending on the number of mobile subscribers, on the capacity of the equipment, on the organization of the network, etc. For example, the HSS XS24 can provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location dependencies, etc.

The S-GW XS22 may terminate the SI interface XS13 towards the RAN XS10, and routes data packets between the RAN XS 10 and the CN XS20. In addition, the S-GW XS22 may be a local mobility anchor point for inter-RAN node handovers and also may provide an anchor for inter-3GPP mobility. Other responsibilities may include lawful intercept, charging, and some policy enforcement.

The P-GW XS23 may terminate an SGi interface toward a PDN. The P-GW XS23 may route data packets between the CN XS20 and external networks such as a network including the application server XS30 (alternatively referred to as application function (AF)) via an Internet Protocol (IP) interface XS25. Generally, the application server XS30 may be an element offering applications that use IP bearer resources with the core network (e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). In this embodiment, the P-GW XS23 is shown to be communicatively coupled to an application server XS30 via an IP communications interface XS25. The application server XS30 can also be configured to support one or more communication services (e.g., Voice-over- Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UEs XS01 and XS02 via the CN XS20.

The P-GW XS23 may further be a node for policy enforcement and charging data collection. Policy and Charging Enforcement Function (PCRF) XS26 is the policy and charging control element of the CN XS20. In a non-roaming scenario, there may be a single PCRF in the Home Public Land Mobile Network (HPLMN) associated with a UE's Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with local breakout of traffic, there may be two PCRFs associated with a UE's IP-CAN session: a Home PCRF (H-PCRF) within an HPLMN and a Visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF XS26 may be communicatively coupled to the application server XS30 via the P-GW XS23. The application server XS30 may signal the PCRF XS26 to indicate a new service flow and select the appropriate Quality of Service (QoS) and charging parameters. The PCRF XS26 may provision this rule into a Policy and Charging Enforcement Function (PCEF) (not shown) with the appropriate traffic flow template (TFT) and QoS class of identifier (QCI), which commences the QoS and charging as specified by the application server XS30.

Figure 8 illustrates an architecture of a system XR00 of a network in accordance with some embodiments. The system XR00 is shown to include a UE XR01, which may be the same or similar to UEs XS01 and XS02 discussed previously; a RAN node XR11, which may be the same or similar to RAN nodes XS11 and XS12 discussed previously; a User Plane Function (UPF) XR02; a Data network (DN) XR03, which may be, for example, operator services, Internet access or 3rd party services; and a 5G Core Network (5GC or CN) XR20.

The CN XR20 may include an Authentication Server Function (AUSF) XR22; a Core Access and Mobility Management Function (AMF) XR21; a Session Management Function (SMF) XR24; a Network Exposure Function (NEF) XR23; a Policy Control function (PCF) XR26; a Network Function (NF) Repository Function (NRF) XR25; a Unified Data Management (UDM) XR27; and an Application Function (AF) XR28. The CN XR20 may also include other elements that are not shown, such as a Structured Data Storage network function (SDSF), an Unstructured Data Storage network function (UDSF), and the like.

The UPF XR02 may act as an anchor point for intra-RAT and inter-RAT mobility, an external protocol data unit (PDU) session point of interconnect to DN XR03, and a branching point to support multi-homed PDU session. The UPF XR02 may also perform packet routing and forwarding, packet inspection, enforce user plane part of policy rules, lawfully intercept packets (UP collection); traffic usage reporting, perform QoS handling for user plane (e.g., packet filtering, gating, UL/DL rate enforcement), perform Uplink

Traffic verification (e.g., SDF to QoS flow mapping), transport level packet marking in the uplink and downlink, and downlink packet buffering and downlink data notification triggering. UPF XR02 may include an uplink classifier to support routing traffic flows to a data network. The DN XR03 may represent various network operator services, Internet access, or third party services. DN XR03 may include, or be similar to, application server XS30 discussed previously.

The AUSF XR22 may store data for authentication of UE XR01 and handle authentication related functionality. Facilitates a common authentication framework for various access types. The AMF XR21 may be responsible for registration management (e.g., for registering UE XR01, etc.), connection management, reachability management, mobility management, and lawful interception of AMF-related events, and access authentication and authorization. AMF XR21 may provide transport for SM messages between UE XR01 and SMF XR24, and act as a transparent proxy for routing SM messages. AMF XR21 may also provide transport for short message service (SMS) messages between UE XR01 and an SMS function (SMSF) (not shown by FIG. 8). AMF XR21 may act as Security Anchor Function (SEA), which may include interaction with the AUSF XR22 and the UE XR01, receipt of an intermediate key that was established as a result of the UE XR01

authentication process. Where USIM based authentication is used, the AMF XR21 may retrieve the security material from the AUSF XR22. AMF XR21 may also include a Security Context Management (SCM) function, which receives a key from the SEA that it uses to derive access-network specific keys. Furthermore, AMF XR21 may be a termination point of RAN CP interface (N2 reference point), a termination point of NAS (Nl) signalling, and perform NAS ciphering and integrity protection.

AMF XR21 may also support NAS signalling with a UE XR01 over an N3 interworking-function (IWF) interface. The N3IWF may be used to provide access to untrusted entities. N3 IWF may be a termination point for the N2 and N3 interfaces for control plane and user plane, respectively, and as such, may handle N2 signalling from SMF and AMF for PDU sessions and QoS, encapsulate/de-encapsulate packets for IPSec and N3 tunnelling, mark N3 user-plane packets in the uplink, and enforce QoS corresponding to N3 packet marking taking into account QoS requirements associated to such marking received over N2. N3IWF may also relay uplink and downlink control-plane NAS (Nl) signalling between the UE XR01 and AMF XR21, and relay uplink and downlink user-plane packets between the UE XR01 and UPF XR02. The N3IWF also provides mechanisms for IPsec tunnel establishment with the UE XR01.

The SMF XR24 may be responsible for session management (e.g., session establishment, modify and release, including tunnel maintain between UPF and AN node); UE IP address allocation & management (including optional Authorization); Selection and control of UP function; Configures traffic steering at UPF to route traffic to proper destination; termination of interfaces towards Policy control functions; control part of policy enforcement and QoS; lawful intercept (for SM events and interface to LI System); termination of SM parts of NAS messages; downlink Data Notification; initiator of AN specific SM information, sent via AMF over N2 to AN; determine SSC mode of a session. The SMF XR24 may include the following roaming functionality: handle local enforcement to apply QoS SLAs (VPLMN); charging data collection and charging interface (VPLMN); lawful intercept (in VPLMN for SM events and interface to LI System); support for interaction with external DN for transport of signalling for PDU session authorization/authenti cation by external DN.

The NEF XR23 may provide means for securely exposing the services and capabilities provided by 3GPP network functions for third party, internal exposure/re- exposure, Application Functions (e.g., AF XR28), edge computing or fog computing systems, etc. In such embodiments, the NEF XR23 may authenticate, authorize, and/or throttle the AFs. NEF XR23 may also translate information exchanged with the AF XR28 and information exchanged with internal network functions. For example, the NEF XR23 may translate between an AF-Service-Identifier and an internal 5GC information. NEF XR23 may also receive information from other network functions (NFs) based on exposed capabilities of other network functions. This information may be stored at the NEF XR23 as structured data, or at a data storage NF using standardized interfaces. The stored information can then be re-exposed by the NEF XR23 to other NFs and AFs, and/or used for other purposes such as analytics.

The NRF XR25 may support service discovery functions, receive NF Discovery Requests from NF instances, and provide the information of the discovered NF instances to the NF instances. NRF XR25 also maintains information of available NF instances and their supported services.

The PCF XR26 may provide policy rules to control plane function(s) to enforce them, and may also support unified policy framework to govern network behaviour. The PCF XR26 may also implement a front end (FE) to access subscription information relevant for policy decisions in a user data repository (UDR) of UDM XR27.

The UDM XR27 may handle subscription-related information to support the network entities' handling of communication sessions, and may store subscription data of UE XR01. The UDM XR27 may include two parts, an application FE and a UDR. The UDM may include a UDM FE, which is in charge of processing of credentials, location management, subscription management and so on. Several different front ends may serve the same user in different transactions. The UDM-FE accesses subscription information stored in the UDR and performs authentication credential processing; user identification handling; access authorization; registration/mobility management; and subscription management. The UDR may interact with PCF XR26. UDM XR27 may also support SMS management, wherein an SMS-FE implements the similar application logic as discussed previously.

The AF XR28 may provide application influence on traffic routing, access to the Network Capability Exposure (NCE), and interact with the policy framework for policy control. The NCE may be a mechanism that allows the 5GC and AF XR28 to provide information to each other viaNEF XR23, which may be used for edge computing implementations. In such implementations, the network operator and third party services may be hosted close to the UE XROl access point of attachment to achieve an efficient service delivery through the reduced end-to-end latency and load on the transport network. For edge computing implementations, the 5GC may select a UPF XR02 close to the UE XROl and execute traffic steering from the UPF XR02 to DN XR03 via the N6 interface. This may be based on the UE subscription data, UE location, and information provided by the AF XR28. In this way, the AF XR28 may influence UPF (re)selection and traffic routing. Based on operator deployment, when AF XR28 is considered to be a trusted entity, the network operator may permit AF XR28 to interact directly with relevant NFs.

As discussed previously, the CN XR20 may include an SMSF, which may be responsible for SMS subscription checking and verification, and relaying SM messages to/from the UE XROl to/from other entities, such as an SMS-GMSC/IWMSC/SMS-router. The SMS may also interact with AMF XR21 and UDM XR27 for notification procedure that the UE XROl is available for SMS transfer (e.g., set a UE not reachable flag, and notifying UDM XR27 when UE XROl is available for SMS).

The system XR00 may include the following service-based interfaces: Namf: Service-based interface exhibited by AMF; Nsmf: Service-based interface exhibited by SMF; Nnef: Service-based interface exhibited by NEF; Npcf: Service-based interface exhibited by PCF; Nudm: Service-based interface exhibited by UDM; Naf: Service-based interface exhibited by AF; Nnrf: Service-based interface exhibited by NRF; and Nausf: Service-based interface exhibited by AUSF.

The system XR00 may include the following reference points: Nl: Reference point between the UE and the AMF; N2: Reference point between the (R)AN and the AMF; N3: Reference point between the (R)AN and the UPF; N4: Reference point between the SMF and the UPF; and N6: Reference point between the UPF and a Data Network. There may be many more reference points and/or service-based interfaces between the NF services in the NFs, however, these interfaces and reference points have been omitted for clarity. For example, an N5 reference point may be between the PCF and the AF; an N7 reference point may be between the PCF and the SMF; an Nl 1 reference point between the AMF and SMF; etc. In some embodiments, the CN XR20 may include an Nx interface, which is an inter-CN interface between the MME (e.g., MME XS21) and the AMF XR21 in order to enable interworking between CN XR20 and CN XS20.

Although not shown by FIG. 8, system XR00 may include multiple RAN nodes

XRl 1 wherein an Xn interface is defined between two or more RAN nodes XR11 (e.g., gNBs and the like) that connect to 5GC XR20, between a RAN node XRl 1 (e.g., gNB) connecting to 5GC XR20 and an eNB (e.g., a RAN node XS11 of FIG. 7), and/or between two eNBs connecting to 5GC XR20.

In some implementations, the Xn interface may include an Xn user plane (Xn-U) interface and an Xn control plane (Xn-C) interface. The Xn-U may provide non- guaranteed delivery of user plane PDUs and support provide data forwarding and flow control functionality. The Xn-C may provide management and error handling

functionality, functionality to manage the Xn-C interface; mobility support for UE XR01 in a connected mode (e.g., CM-CONNECTED) including functionality to manage the UE mobility for connected mode between one or more RAN nodes XRl 1. The mobility support may include context transfer from an old (source) serving RAN node XRl 1 to new (target) serving RAN node XRl 1 ; and control of user plane tunnels between old (source) serving RAN node XRl 1 to new (target) serving RAN node XRl 1.

A protocol stack of the Xn-U may include a transport network layer built on

Internet Protocol (IP) transport layer, and a GTP-U layer on top of a UDP and/or IP layer(s) to carry user plane PDUs. The Xn-C protocol stack may include an application layer signaling protocol (referred to as Xn Application Protocol (Xn-AP)) and a transport network layer that is built on an SCTP layer. The SCTP layer may be on top of an IP layer. The SCTP layer provides the guaranteed delivery of application layer messages. In the transport IP layer point-to-point transmission is used to deliver the signaling PDUs. In other implementations, the Xn-U protocol stack and/or the Xn-C protocol stack may be the same or similar to the user plane and/or control plane protocol stack(s) shown and described herein.

Figure 9 illustrates example components of a device XT00 in accordance with some embodiments. In some embodiments, the device XT00 may include application circuitry XT02, baseband circuitry XT04, Radio Frequency (RF) circuitry XT06, front-end module (FEM) circuitry XT08, one or more antennas XT10, and power management circuitry (PMC) XT 12 coupled together at least as shown. The components of the illustrated device XTOO may be included in a UE or a RAN node. In some embodiments, the device XTOO may include less elements (e.g., a RAN node may not utilize application circuitry XT02, and instead include a processor/controller to process IP data received from an EPC). In some embodiments, the device XTOO may include additional elements such as, for example, memory /storage, display, camera, sensor, or input/output (I/O) interface. In other embodiments, the components described below may be included in more than one device (e.g., said circuitries may be separately included in more than one device for Cloud-RAN (C-RAN) implementations).

The application circuitry XT02 may include one or more application processors. For example, the application circuitry XT02 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled with or may include memory /storage and may be configured to execute instructions stored in the memory /storage to enable various applications or operating systems to run on the device XTOO. In some embodiments, processors of application circuitry XT02 may process IP data packets received from an EPC.

The baseband circuitry XT04 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry XT04 may include one or more baseband processors or control logic to process baseband signals received from a receive signal path of the RF circuitry XT06 and to generate baseband signals for a transmit signal path of the RF circuitry XT06. Baseband processing circuitry XT04 may interface with the application circuitry XT02 for generation and processing of the baseband signals and for controlling operations of the RF circuitry XT06. For example, in some embodiments, the baseband circuitry XT04 may include a third generation (3G) baseband processor XT04A, a fourth generation (4G) baseband processor XT04B, a fifth generation (5G) baseband processor XT04C, or other baseband processor(s) XT04D for other existing generations, generations in development or to be developed in the future (e.g., second generation (2G), sixth generation (6G), etc.). The baseband circuitry XT04 (e.g., one or more of baseband processors XT04A-D) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry XT06. In other embodiments, some or all of the functionality of baseband processors XT04A-D may be included in modules stored in the memory XT04G and executed via a Central Processing Unit (CPU) XT04E. The radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some embodiments, modulation/demodulation circuitry of the baseband circuitry XT04 may include Fast-Fourier Transform (FFT), precoding, or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry XT04 may include convolution, tail-biting convolution, turbo, Viterbi, or Low Density Parity Check (LDPC) encoder/decoder functionality.

Embodiments of modulation/demodulation and encoder/decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments.

In some embodiments, the baseband circuitry XT04 may include one or more audio digital signal processor(s) (DSP) XT04F. The audio DSP(s) XT04F may include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry XT04 and the application circuitry XT02 may be implemented together such as, for example, on a system on a chip (SOC).

In some embodiments, the baseband circuitry XT04 may provide for

communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry XT04 may support communication with an evolved universal terrestrial radio access network (E-UTRAN) or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which the baseband circuitry XT04 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

RF circuitry XT06 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various

embodiments, the RF circuitry XT06 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry XT06 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry XT08 and provide baseband signals to the baseband circuitry XT04. RF circuitry XT06 may also include a transmit signal path which may include circuitry to up- convert baseband signals provided by the baseband circuitry XT04 and provide RF output signals to the FEM circuitry XT08 for transmission. In some embodiments, the receive signal path of the RF circuitry XT06 may include mixer circuitry XT06a, amplifier circuitry XT06b and filter circuitry XT06c. In some embodiments, the transmit signal path of the RF circuitry XT06 may include filter circuitry XT06c and mixer circuitry XT06a. RF circuitry XT06 may also include synthesizer circuitry XT06d for synthesizing a frequency for use by the mixer circuitry XT06a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry XT06a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry XT08 based on the synthesized frequency provided by synthesizer circuitry XT06d. The amplifier circuitry XT06b may be configured to amplify the down-converted signals and the filter circuitry XT06c may be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided to the baseband circuitry XT04 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry XT06a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry XT06a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry XT06d to generate RF output signals for the FEM circuitry XT08. The baseband signals may be provided by the baseband circuitry XT04 and may be filtered by filter circuitry XT06c.

In some embodiments, the mixer circuitry XT06a of the receive signal path and the mixer circuitry XT06a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and upconversion, respectively. In some embodiments, the mixer circuitry XT06a of the receive signal path and the mixer circuitry XT06a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rej ection). In some embodiments, the mixer circuitry XT06a of the receive signal path and the mixer circuitry XT06a of the transmit signal path may be arranged for direct downconversion and direct upconversion, respectively. In some embodiments, the mixer circuitry XT06a of the receive signal path and the mixer circuitry XT06a of the transmit signal path may be configured for superheterodyne operation. In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, the RF circuitry XT06 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry XT04 may include a digital baseband interface to communicate with the RF circuitry XT06.

In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, although the scope of the embodiments is not limited in this respect.

In some embodiments, the synthesizer circuitry XT06d may be a fractional-N synthesizer or a fractional N/N+l synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry XT06d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

The synthesizer circuitry XT06d may be configured to synthesize an output frequency for use by the mixer circuitry XT06a of the RF circuitry XT06 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry XT06d may be a fractional N/N+l synthesizer.

In some embodiments, frequency input may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. Divider control input may be provided by either the baseband circuitry XT04 or the application circuitry XT02 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table based on a channel indicated by the application circuitry XT02.

Synthesizer circuitry XT06d of the RF circuitry XT06 may include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DP A). In some embodiments, the DMD may be configured to divide the input signal by either N or N+l (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

In some embodiments, synthesizer circuitry XT06d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (fLO). In some embodiments, the RF circuitry XT06 may include an IQ/polar converter.

FEM circuitry XT08 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas XT10, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry XT06 for further processing. FEM circuitry XT08 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry XT06 for transmission by one or more of the one or more antennas XT10. In various embodiments, the amplification through the transmit or receive signal paths may be done solely in the RF circuitry XT06, solely in the FEM circuitry XT08, or in both the RF circuitry XT06 and the FEM circuitry XT08.

In some embodiments, the FEM circuitry XT08 may include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry XT08 may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include an LNA to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry XT06). The transmit signal path of the FEM circuitry XT08 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry XT06), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas XT10).

In some embodiments, the PMC XT12 may manage power provided to the baseband circuitry XT04. In particular, the PMC XT12 may control power-source selection, voltage scaling, battery charging, or DC-to-DC conversion. The PMC XT12 may often be included when the device XT00 is capable of being powered by a battery, for example, when the device is included in a UE. The PMC XT 12 may increase the power conversion efficiency while providing desirable implementation size and heat dissipation characteristics.

FIG. 9 shows the PMC XT12 coupled only with the baseband circuitry XT04. However, in other embodiments, the PMC XT12 may be additionally or alternatively coupled with, and perform similar power management operations for, other components such as, but not limited to, application circuitry XT02, RF circuitry XT06, or FEM circuitry XT08.

In some embodiments, the PMC XT12 may control, or otherwise be part of, various power saving mechanisms of the device XTOO. For example, if the device XTOO is in an RRC_Connected state, where it is still connected to the RAN node as it expects to receive traffic shortly, then it may enter a state known as Discontinuous Reception Mode (DRX) after a period of inactivity. During this state, the device XTOO may power down for brief intervals of time and thus save power.

If there is no data traffic activity for an extended period of time, then the device XTOO may transition off to an RRC Idle state, where it disconnects from the network and does not perform operations such as channel quality feedback, handover, etc. The device XTOO goes into a very low power state and it performs paging where again it periodically wakes up to listen to the network and then powers down again. The device XTOO may not receive data in this state, in order to receive data, it must transition back to

RRC_Connected state.

An additional power saving mode may allow a device to be unavailable to the network for periods longer than a paging interval (ranging from seconds to a few hours). During this time, the device is totally unreachable to the network and may power down completely. Any data sent during this time incurs a large delay and it is assumed the delay is acceptable.

Processors of the application circuitry XT02 and processors of the baseband circuitry XT04 may be used to execute elements of one or more instances of a protocol stack. For example, processors of the baseband circuitry XT04, alone or in combination, may be used to execute Layer 3, Layer 2, or Layer 1 functionality, while processors of the application circuitry XT04 may utilize data (e.g., packet data) received from these layers and further execute Layer 4 functionality (e.g., transmission communication protocol (TCP) and user datagram protocol (UDP) layers). As referred to herein, Layer 3 may comprise a radio resource control (RRC) layer, described in further detail below. As referred to herein, Layer 2 may comprise a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer, described in further detail below. As referred to herein, Layer 1 may comprise a physical (PHY) layer of a UE/RAN node, described in further detail below.

Figure 10 illustrates example interfaces of baseband circuitry in accordance with some embodiments. As discussed above, the baseband circuitry XT04 of FIG. 9 may comprise processors XT04A-XT04E and a memory XT04G utilized by said processors. Each of the processors XT04A-XT04E may include a memory interface, XU04A-XU04E, respectively, to send/receive data to/from the memory XT04G.

The baseband circuitry XT04 may further include one or more interfaces to communicatively couple to other circuitries/devices, such as a memory interface XU12 (e.g., an interface to send/receive data to/from memory external to the baseband circuitry XT04), an application circuitry interface XU14 (e.g., an interface to send/receive data to/from the application circuitry XT02 of FIG. 9), an RF circuitry interface XU16 (e.g., an interface to send/receive data to/from RF circuitry XT06 of FIG. 9), a wireless hardware connectivity interface XU18 (e.g., an interface to send/receive data to/from Near Field Communication (NFC) components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components), and a power management interface XU20 (e.g., an interface to send/receive power or control signals to/from the PMC XT 12).

Figure 11 is an illustration of a control plane protocol stack in accordance with some embodiments. In this embodiment, a control plane XV00 is shown as a

communications protocol stack between the UE XSOl (or altematively, the UE XS02), the RAN node XS11 (or alternatively, the RAN node XS 12), and the MME XS21.

The PHY layer XV01 may transmit or receive information used by the MAC layer XV 02 over one or more air interfaces. The PHY layer XV01 may further perform link adaptation or adaptive modulation and coding (AMC), power control, cell search (e.g., for initial synchronization and handover purposes), and other measurements used by higher layers, such as the RRC layer XV05. The PHY layer XV01 may still further perform error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, modulation/demodulation of physical channels, interleaving, rate matching, mapping onto physical channels, and Multiple Input Multiple Output (MIMO) antenna processing.

The MAC layer XV 02 may perform mapping between logical channels and transport channels, multiplexing of MAC service data units (SDUs) from one or more logical channels onto transport blocks (TB) to be delivered to PHY via transport channels, de-multiplexing MAC SDUs to one or more logical channels from transport blocks (TB) delivered from the PHY via transport channels, multiplexing MAC SDUs onto TBs, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ), and logical channel prioritization.

The RLC layer XV03 may operate in a plurality of modes of operation, including: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). The RLC layer XV03 may execute transfer of upper layer protocol data units (PDUs), error correction through automatic repeat request (ARQ) for AM data transfers, and concatenation, segmentation and reassembly of RLC SDUs for UM and AM data transfers. The RLC layer XV03 may also execute re-segmentation of RLC data PDUs for AM data transfers, reorder RLC data PDUs for UM and AM data transfers, detect duplicate data for UM and AM data transfers, discard RLC SDUs for UM and AM data transfers, detect protocol errors for AM data transfers, and perform RLC re-establishment.

The PDCP layer XV 04 may execute header compression and decompression of IP data, maintain PDCP Sequence Numbers (SNs), perform in-sequence delivery of upper layer PDUs at re-establishment of lower layers, eliminate duplicates of lower layer SDUs at re-establishment of lower layers for radio bearers mapped on RLC AM, cipher and decipher control plane data, perform integrity protection and integrity verification of control plane data, control timer-based discard of data, and perform security operations (e.g., ciphering, deciphering, integrity protection, integrity verification, etc.).

The main services and functions of the RRC layer XV05 may include broadcast of system information (e.g., included in Master Information Blocks (MIBs) or System Information Blocks (SIBs) related to the non-access stratum (NAS)), broadcast of system information related to the access stratum (AS), paging, establishment, maintenance and release of an RRC connection between the UE and E-UTRAN (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), establishment, configuration, maintenance and release of point to point Radio Bearers, security functions including key management, inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting. Said MIBs and SIBs may comprise one or more information elements (IEs), which may each comprise individual data fields or data structures.

The UE XS01 and the RAN node XS11 may utilize a Uu interface (e.g., an LTE- Uu interface) to exchange control plane data via a protocol stack comprising the PHY layer XV01, the MAC layer XV02, the RLC layer XV03, the PDCP layer XV04, and the RRC layer XV05.

The non-access stratum (NAS) protocols XV06 form the highest stratum of the control plane between the UE XS01 and the MME XS21. The NAS protocols XV06 support the mobility of the UE XS01 and the session management procedures to establish and maintain IP connectivity between the UE XS01 and the P-GW XS23.

The SI Application Protocol (Sl-AP) layer XV15 may support the functions of the SI interface and comprise Elementary Procedures (EPs). An EP is a unit of interaction between the RAN node XS11 and the CN XS20. The Sl-AP layer services may comprise two groups: UE-associated services and non UE-associated services. These services perform functions including, but not limited to: E-UTRAN Radio Access Bearer (E-RAB) management, UE capability indication, mobility, NAS signaling transport, RAN

Information Management (RIM), and configuration transfer.

The Stream Control Transmission Protocol (SCTP) layer (alternatively referred to as the SCTP/IP layer) XV14 may ensure reliable delivery of signaling messages between the RAN node XS11 and the MME XS21 based, in part, on the IP protocol, supported by the IP layer XV13. The L2 layer XV12 and the LI layer XVI 1 may refer to

communication links (e.g., wired or wireless) used by the RAN node and the MME to exchange information.

The RAN node XS 11 and the MME XS21 may utilize an S 1 -MME interface to exchange control plane data via a protocol stack comprising the LI layer XVI 1, the L2 layer XV 12, the IP layer XV 13, the SCTP layer XV 14, and the Sl-AP layer XV15.

Figure 12 is an illustration of a user plane protocol stack in accordance with some embodiments. In this embodiment, a user plane XWOO is shown as a communications protocol stack between the UE XS01 (or alternatively, the UE XS02), the RAN node

XS 11 (or altematively, the RAN node XS 12), the S-GW XS22, and the P-GW XS23. The user plane XWOO may utilize at least some of the same protocol layers as the control plane XV00. For example, the UE XS01 and the RAN node XS11 may utilize a Uu interface (e.g., an LTE-Uu interface) to exchange user plane data via a protocol stack comprising the PHY layer XV01, the MAC layer XV02, the RLC layer XV03, the PDCP layer XV04.

The General Packet Radio Service (GPRS) Tunneling Protocol for the user plane (GTP-U) layer XW04 may be used for carrying user data within the GPRS core network and between the radio access network and the core network. The user data transported can be packets in any of IPv4, IPv6, or PPP formats, for example. The UDP and IP security (UDP/IP) layer XW03 may provide checksums for data integrity, port numbers for addressing different functions at the source and destination, and encryption and authentication on the selected data flows. The RAN node XS11 and the S-GW XS22 may utilize an Sl-U interface to exchange user plane data via a protocol stack comprising the LI layer XVI 1, the L2 layer XV12, the UDP/IP layer XW03, and the GTP-U layer XW04. The S-GW XS22 and the P-GW XS23 may utilize an S5/S8a interface to exchange user plane data via a protocol stack comprising the LI layer XVI 1, the L2 layer XV12, the UDP/IP layer XW03, and the GTP-U layer XW04. As discussed above with respect to FIG. 11, NAS protocols support the mobility of the UE XSOl and the session management procedures to establish and maintain IP connectivity between the UE XSOl and the P-GW XS23.

Figure 13 illustrates components of a core network in accordance with some embodiments. The components of the CN XS20 may be implemented in one physical node or separate physical nodes including components to read and execute instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine- readable storage medium). In some embodiments, Network Functions Virtualization (NFV) is utilized to virtualize any or all of the above described network node functions via executable instructions stored in one or more computer readable storage mediums

(described in further detail below). A logical instantiation of the CN XS20 may be referred to as a network slice XXOl. A logical instantiation of a portion of the CN XS20 may be referred to as a network sub-slice XX02 (e.g., the network sub-slice XX02 is shown to include the PGW XS23 and the PCRF XS26).

NFV architectures and infrastructures may be used to virtualize one or more network functions, alternatively performed by proprietary hardware, onto physical resources comprising a combination of industry -standard server hardware, storage hardware, or switches. In other words, NFV systems can be used to execute virtual or reconfigurable implementations of one or more EPC components/functions.

Figure 14 is a block diagram illustrating components, according to some example embodiments, of a system XY00 to support NFV. The system XY00 is illustrated as including a virtualized infrastructure manager (VIM) XY02, a network function virtualization infrastructure (NFVI) XY04, a VNF manager (VNFM) XY06, virtualized network functions (VNFs) XY08, an element manager (EM) XY10, an NFV Orchestrator (NFVO) XY12, and a network manager (NM) XY14. The VIM XY02 manages the resources of the NFVI XY04. The NFVI XY04 can include physical or virtual resources and applications (including hypervisors) used to execute the system XY00. The VIM XY02 may manage the life cycle of virtual resources with the NFVI XY04 (e.g., creation, maintenance, and tear down of virtual machines (VMs) associated with one or more physical resources), track VM instances, track performance, fault and security of VM instances and associated physical resources, and expose VM instances and associated physical resources to other management systems.

The VNFM XY06 may manage the VNFs XY08. The VNFs XY08 may be used to execute EPC components/functions. The VNFM XY06 may manage the life cycle of the VNFs XY08 and track performance, fault and security of the virtual aspects of VNFs XY08. The EM XY10 may track the performance, fault and security of the functional aspects of VNFs XY08. The tracking data from the VNFM XY06 and the EM XY10 may comprise, for example, performance measurement (PM) data used by the VIM XY02 or the NFVI XY04. Both the VNFM XY06 and the EM XY10 can scale up/down the quantity of VNFs of the system XY00.

The NFVO XY12 may coordinate, authorize, release and engage resources of the NFVI XY04 in order to provide the requested service (e.g., to execute an EPC function, component, or slice). The NM XY14 may provide a package of end-user functions with the responsibility for the management of a network, which may include network elements with VNFs, non-virtualized network functions, or both (management of the VNFs may occur via the EM XY10).

Figure 15 is a block diagram illustrating components, according to some example embodiments, able to read instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and perform any one or more of the methodologies discussed herein. Specifically, FIG. 15 shows a diagrammatic representation of hardware resources XZOO including one or more processors (or processor cores) XZ10, one or more memory /storage devices XZ20, and one or more

communication resources XZ30, each of which may be communicatively coupled via a bus XZ40. For embodiments where node virtualization (e.g., NFV) is utilized, a hypervisor XZ02 may be executed to provide an execution environment for one or more network slices/sub-slices to utilize the hardware resources XZ00.

The processors XZ10 (e.g., a central processing unit (CPU), a reduced instruction set computing (RISC) processor, a complex instruction set computing (CISC) processor, a graphics processing unit (GPU), a digital signal processor (DSP) such as a baseband processor, an application specific integrated circuit (ASIC), a radio-frequency integrated circuit (RFIC), another processor, or any suitable combination thereof) may include, for example, a processor XZ12 and a processor XZ14.

The memory /storage devices XZ20 may include main memory, disk storage, or any suitable combination thereof. The memory /storage devices XZ20 may include, but are not limited to, any type of volatile or non-volatile memory such as dynamic random access memory (DRAM), static random-access memory (SRAM), erasable programmable readonly memory (EPROM), electrically erasable programmable read-only memory

(EEPROM), Flash memory, solid-state storage, etc.

The communication resources XZ30 may include interconnection or network interface components or other suitable devices to communicate with one or more peripheral devices XZ04 or one or more databases XZ06 via a network XZ08. For example, the communication resources XZ30 may include wired communication components (e.g., for coupling via a Universal Serial Bus (USB)), cellular communication components, NFC components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components.

Instructions XZ50 may comprise software, a program, an application, an applet, an app, or other executable code for causing at least any of the processors XZ10 to perform any one or more of the methodologies discussed herein. The instructions XZ50 may reside, completely or partially, within at least one of the processors XZ10 (e.g., within the processor's cache memory), the memory /storage devices XZ20, or any suitable combination thereof. Furthermore, any portion of the instructions XZ50 may be transferred to the hardware resources XZ00 from any combination of the peripheral devices XZ04 or the databases XZ06. Accordingly, the memory of processors XZ10, the memory /storage devices XZ20, the peripheral devices XZ04, and the databases XZ06 are examples of computer-readable and machine-readable media.

Example 1 is a user equipment (UE) to operate in a cellular mobile network, whereby the radio access network (RAN) of the cellular mobile network offers connections to a multitude of different types of core networks (CNs), the UE is to indicate to the RAN a first type of CN from the multitude of different types of CNs to which it wants to send a registration request, the UE, based on the receipt of a registration rej ect with a specific reject cause, determines that it is not allowed to register with the first type of CN, selects a second type of CN from the multitude of different types of CNs, and initiates a registration procedure for the second type of CN. Example 2 is the UE according to example 1 or some other example herein, whereby the first type of CN is a 5th Generation Core Network (5GC) and the second type of CN is an Evolved Packet Core (EPC).

Example 3 is the UE according to example 2 or some other example herein, whereby the UE indicates its request to send the registration request to the 5GC by including an Nl capability indication in the signalling to the RAN.

Example 4 is the UE according to example 1 or some other example herein, whereby the RAN is an evolved universal mobile telecommunication system terrestrial radio access network (E-UTRAN).

Example 5 is the UE according to example 1 or some other example herein, whereby the UE receives in the system information broadcast of the RAN an indication indicating to which types of CNs the RAN offers a connection.

Example 6 is the UE according to example 1 or some other example herein, whereby the protocol the UE uses to register with the first type of CN is different from the protocol the UE uses to register with the second type of CN.

Example 7 is the UE according to example 1 or some other example herein, whereby in certain cells of the RAN may offer a connection to one type of CN only.

Example 8 is the UE according to example 7 or some other example herein, whereby, if the only type of CN to which the RAN offers a connection is the first type of CN, the UE attempts to find a different cell offering a connection to a different type of CN.

Example 9 is a cellular mobile network, whereby the radio access network (RAN) of the cellular mobile network offers connections to a multitude of different types of core networks (CNs), to receive from a user equipment (UE) a registration request, via the RAN, for a first type of CN from the multitude of different types of CNs, to determine that that the UE is not allowed to register with the first type of CN, and to reject the registration request with a specific reject cause indicating to the UE that it may initiate, via the RAN, a registration procedure for another type of CN from the multitude of different types of CNs.

Example 10 is a user equipment (UE) to operate in a cellular mobile network, whereby the radio access network (RAN) of the cellular mobile network offers connections to a multitude of different types of core networks (CNs), the UE is to prefer registration, via a first radio access technology (RAT), with a first type of CN from the multitude of different types of CNs, the UE, based on the receipt of a registration reject via a second RAT, with a specific reject cause, determines to change its configuration so that it prefers registration, via the first RAT, with a second type of CN from the multitude of different types of CNs.

Example 11 is the UE according to example 10 or some other example herein, whereby the first RAT is a third generation partnership project (3GPP) evolved universal mobile telecommunication system terrestrial radio access network (E-UTRAN), the first type of CN is a 5th Generation Core Network (5GC), the second type of RAT is a 3GPP New Radio (NR), and the second type of CN is an Evolved Packet Core (EPC).

Example 12 is the UE according to example 10 or some other example herein, whereby if the UE is to prefer registration, via a first radio access technology (RAT), with a first type of CN from the multitude of different types of CNs, then for cell selection and cell re-selection the UE prefers cells offering a connection to the first type of CN over cells offering a connection to the second type of CN only.

Example 13 is the UE according to example 10, whereby if the UE is to prefer registration, via a first radio access technology (RAT), with a second type of CN from the multitude of different types of CNs, then for cell selection and cell re-selection the UE prefers cells offering a connection to the first type of CN over cells offering a connection to the first type of CN only.

Example 14 may include an apparatus comprising means to perform one or more elements of a method described in or related to any of examples 1-13, or any other method or process described herein.

Example 15 may include one or more non-transitory computer-readable media comprising instructions to cause an electronic device, upon execution of the instructions by one or more processors of the electronic device, to perform one or more elements of a method described in or related to any of examples 1-13, or any other method or process described herein.

Example 16 may include an apparatus comprising logic, modules, or circuitry to perform one or more elements of a method described in or related to any of examples 1- 13, or any other method or process described herein.

Example 17 may include a method, technique, or process as described in or related to any of examples 1-13, or portions or parts thereof.

Example 18 may include an apparatus comprising: one or more processors and one or more computer readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform the method, techniques, or process as described in or related to any of examples 1-13, or portions thereof.

Example 19 may include a signal as described in or related to any of examples 1 - 13, or portions or parts thereof.

Example 20 may include a signal in a wireless network as shown and described herein.

Example 21 may include a method of communicating in a wireless network as shown and described herein.

Example 22 may include a system for providing wireless communication as shown and described herein.

Example 23 may include a device for providing wireless communication as shown and described herein.

Example 24 may include one or more computer-readable media having instructions stored thereon, wherein the instructions, in response to execution by a user equipment (UE), cause the UE to generate a registration request for transmission to a network, identify a registration reject message received from the network in response to the registration request, wherein the registration reject message includes an indication that Nl mode is not allowed, and disable Nl mode radio capability based on the indication.

Example 25 may include the computer-readable media of example 24 or any other example herein, wherein the instructions, in response to execution by the UE, further cause the UE to identify a public land mobile network (PLMN) identity (ID) associated with the registration rej ect message, and cause the PLMN ID to be stored as in a list of PLMNs where Nl mode is not allowed.

Example 26 may include the computer-readable media of example 25 or any other example herein, wherein the instructions, in response to execution by the UE, further cause the PLMN ID to be deleted from the list of PLMNs when the UE is switched off or at expiration of a time interval.

Example 27 may include the computer-readable media of example 25 or any other example herein, wherein the instructions, in response to execution by the UE, further cause the UE to avoid initiation of subsequent registration requests for use of an Nl interface of a PLMN associated with the PLMN ID.

Example 28 may include the computer-readable media of any of examples 24-27 or any other example herein, wherein transmission to the network includes transmission to an evolved universal mobile telecommunication system terrestrial radio access network (E-UTRAN) access point, and wherein the E-UTRAN access point is connected to a fifth generation core network (5GC) and an evolved packet core (EPC).

Example 29 may include the computer-readable media of example 28 or any other example herein, wherein the instructions, in response to execution by the UE, further cause the UE to generate a second registration request for transmission to the E-UTRAN access point after the UE has disabled Nl mode radio capability, wherein the second registration request comprises an EPC non-access stratum (NAS) attach request for registration with the EPC.

Example 30 may include the computer-readable media of any of examples 24-27 or any other example herein, wherein the registration request includes an indication that the UE has Nl mode radio capability.

Example 31 may include an apparatus for a user equipment (UE), comprising circuitry to generate a registration request for transmission to a network, identify a registration reject message received from the network in response to the registration request, wherein the registration reject message includes an indication that Nl mode is not allowed, and disable Nl mode radio capability based on the indication, and memory to store the registration request.

Example 32 may include the apparatus of example 31 or any other example herein, wherein the circuitry is further to identify a public land mobile network (PLMN) identity (ID) associated with the registration reject message, and cause the PLMN ID to be stored in a list of PLMNs where Nl mode is not allowed.

Example 33 may include the apparatus of example 32 or any other example herein, wherein the circuitry is further to delete the PLMN ID from the list of PLMNs when the UE is switched off or at expiration of a time interval.

Example 34 may include the apparatus of example 32 or any other example herein, wherein the circuitry is further to avoid initiation of subsequent registration requests for use of an Nl interface of a PLMN associated with the PLMN ID.

Example 35 may include the apparatus of any of examples 31 -34 or any other example herein, wherein transmission to the network includes transmission to an evolved universal mobile telecommunication system terrestrial radio access network (E-UTRAN) access point, and wherein the E-UTRAN access point is coupled to a fifth generation core network (5GC) and an evolved packet core (EPC).

Example 36 may include the apparatus of example 35 or any other example herein, wherein the circuitry is further to generate a second registration request for transmission to the E-UTRAN access point after the UE has disabled Nl mode radio capability, wherein the second registration request comprises an EPC non-access stratum (NAS) attach request for registration with the EPC.

Example 37 may include the apparatus of any of examples 31-34 or any other example herein, wherein the registration request includes an indication that the UE has Nl mode radio capability.

Example 38 may include one or more computer-readable media having instructions stored thereon, wherein the instructions, in response to execution by an access point, cause the access point to identify a registration request received from a user equipment (UE), determine that the registration request is not accepted by a fifth generation core network (5GC), and cause a registration reject to be transmitted to the UE, wherein the registration reject indicates Nl mode is not allowed.

Example 39 may include the computer-readable media of example 38 or any other example herein, wherein to determine that the registration request is not accepted by the 5GC includes to route the registration request to an access and mobility management function (AMF), and identify the registration reject received from the AMF.

Example 40 may include the computer-readable media of any of examples 38 or 39 or any other example herein, wherein to determine that the registration request is not accepted by the 5GC includes to determine that the registration request is not accepted by the 5GC based on subscription information associated with the UE.

Example 41 may include the computer-readable media of any of examples 38 or 39 or any other example herein, wherein the instructions, in response to execution by the access point, further cause the access point to identify an attach request received from the UE, wherein the attach request does not include a 5GC requested indication, and direct the attach request to a mobility management entity (MME).

Example 42 may include the computer-readable media of any of examples 38 or 39 or any other example herein, wherein the access point is an evolved universal mobile telecommunication system terrestrial radio access network (E-UTRAN) access point, and wherein the E-UTRAN access point is coupled to a fifth generation core network (5GC) and an evolved packet core (EPC).

Example 43 may include the computer-readable media of example 42 or any other example herein, wherein the E-UTRAN access point is an evolved NodeB (eNB).

Example 44 may include an apparatus for an access point, comprising circuitry to identify a registration request received from a user equipment (UE), determine that the registration request is not accepted by a fifth generation core network (5GC), and cause a registration reject to be transmitted to the UE, wherein the registration reject indicates Nl mode is not allowed, and memory to store the registration request and the rejection reject.

Example 45 may include the apparatus of example 44 or any other example herein, wherein to determine that the registration request is not accepted by the 5GC includes to route the registration request to an access and mobility management function (AMF), and identify the registration reject received from the AMF.

Example 46 may include the apparatus of any of examples 44 or 45 or any other example herein, wherein to determine that the registration request is not accepted by the 5GC includes to determine that the registration request is not accepted by the 5GC based on subscription information associated with the UE.

Example 47 may include the apparatus of any of examples 44 or 45 or any other example herein, wherein the circuitry is further to identify an attach request received from the UE, wherein the attach request does not include a 5GC requested indication, and direct the attach request to a mobility management entity (MME).

Example 48 may include the apparatus of any of examples 44 or 45 or any other example herein, wherein the access point is an evolved universal mobile

telecommunication system terrestrial radio access network (E-UTRAN) access point, and wherein the E-UTRAN access point is coupled to a fifth generation core network (5GC) and an evolved packet core (EPC).

Example 49 may include a method for a user equipment (UE), comprising causing the UE to generate a registration request for transmission to a network, identifying or causing to identify a registration reject message received from the network in response to the registration request, wherein the registration rej ect message includes an indication that Nl mode is not allowed, and disable Nl mode radio capability based on the indication.

Example 50 may include the method of example 49 or any other example herein, further comprising causing the UE to identify a public land mobile network (PLMN) identity (ID) associated with the registration reject message, and causing the PLMN ID to be stored as in a list of PLMNs where Nl mode is not allowed.

Example 51 may include the method of example 50 or any other example herein, further comprising causing the PLMN ID to be deleted from the list of PLMNs when the UE is switched off or at expiration of a time interval.

Example 52 may include the method of example 50 or any other example herein, further comprising causing the UE to avoid initiation of subsequent registration requests for use of an Nl interface of a PLMN associated with the PLMN ID.

Example 53 may include the method of any of examples 49-52 or any other example herein, wherein transmission to the network includes transmission to an evolved universal mobile telecommunication system terrestrial radio access network (E-UTRAN) access point, and wherein the E-UTRAN access point is connected to a fifth generation core network (5GC) and an evolved packet core (EPC).

Example 54 may include the method of example 53 or any other example herein, further comprising causing the UE to generate a second registration request for transmission to the E-UTRAN access point after the UE has disabled Nl mode radio capability, wherein the second registration request comprises an EPC non-access stratum (NAS) attach request for registration with the EPC.

Example 55 may include the method of any of examples 49-52 or any other example herein, wherein the registration request includes an indication that the UE has Nl mode radio capability.

Example 56 may include a method for a user equipment (UE), comprising generating or causing to generate a registration request for transmission to a network, identifying or causing to identify a registration rej ect message received from the network in response to the registration request, wherein the registration reject message includes an indication that Nl mode is not allowed, and disabling or causing to disable Nl mode radio capability based on the indication, and storing or causing to store the registration request.

Example 57 may include the method of example 56 or any other example herein, further comprising identifying or causing to identify a public land mobile network (PLMN) identity (ID) associated with the registration reject message, and causing the PLMN ID to be stored in a list of PLMNs where Nl mode is not allowed.

Example 58 may include the method of example 57 or any other example herein, further comprising deleting or causing to delete the PLMN ID from the list of PLMNs when the UE is switched off or at expiration of a time interval.

Example 59 may include the method of example 57 or any other example herein, further comprising avoiding or causing to avoid initiation of subsequent registration requests for use of an Nl interface of a PLMN associated with the PLMN ID.

Example 60 may include the method of any of examples 56-59 or any other example herein, wherein transmission to the network includes transmission to an evolved universal mobile telecommunication system terrestrial radio access network (E-UTRAN) access point, and wherein the E-UTRAN access point is coupled to a fifth generation core network (5GC) and an evolved packet core (EPC).

Example 61 may include the method of example 60 or any other example herein, further comprising generating or causing to generate a second registration request for transmission to the E-UTRAN access point after the UE has disabled Nl mode radio capability, wherein the second registration request comprises an EPC non-access stratum (NAS) attach request for registration with the EPC.

Example 62 may include the method of any of examples 56-59 or any other example herein, wherein the registration request includes an indication that the UE has Nl mode radio capability.

Example 63 may include method for an access point, comprising identifying or causing to identify a registration request received from a user equipment (UE), determining or causing to determine that the registration request is not accepted by a fifth generation core network (5GC), and causing a registration reject to be transmitted to the UE, wherein the registration reject indicates Nl mode is not allowed.

Example 64 may include the method of example 63 or any other example herein, wherein determining or causing to determine that the registration request is not accepted by the 5GC includes routing or causing to route the registration request to an access and mobility management function (AMF), and identifying or causing to identify the registration reject received from the AMF.

Example 65 may include the method of any of examples 63 or 64 or any other example herein, wherein determining or causing to determine that the registration request is not accepted by the 5GC includes determining or causing to determine that the registration request is not accepted by the 5GC based on subscription information associated with the UE.

Example 66 may include the method of any of examples 63 or 64 or any other example herein, further comprising identifying or causing to identify an attach request received from the UE, wherein the attach request does not include a 5GC requested indication, and directing or causing to direct the attach request to a mobility management entity (MME).

Example 67 may include the method of any of examples 63 or 64 or any other example herein, wherein the access point is an evolved universal mobile

telecommunication system terrestrial radio access network (E-UTRAN) access point, and wherein the E-UTRAN access point is coupled to a fifth generation core network (5GC) and an evolved packet core (EPC). Example 68 may include the method of example 67 or any other example herein, wherein the E-UTRAN access point is an evolved NodeB (eNB).

Example 69 may include a method for an access point, comprising identifying or causing to identify a registration request received from a user equipment (UE), determining or causing to determine that the registration request is not accepted by a fifth generation core network (5GC), causing a registration reject to be transmitted to the UE, wherein the registration reject indicates Nl mode is not allowed, and storing or causing to store the registration request and the rejection reject.

Example 70 may include the method of example 69 or any other example herein, wherein determining or causing to determine that the registration request is not accepted by the 5GC includes routing or causing to route the registration request to an access and mobility management function (AMF), and identifying or causing to identify the registration reject received from the AMF.

Example 71 may include the method of any of examples 69 or 70 or any other example herein, wherein determining or causing to determine that the registration request is not accepted by the 5GC includes determining or causing to determine that the registration request is not accepted by the 5GC based on subscription information associated with the UE.

Example 72 may include the method of any of examples 69 or 70 or any other example herein, further comprising identifying or causing to identify an attach request received from the UE, wherein the attach request does not include a 5GC requested indication, and directing or causing to direct the attach request to a mobility management entity (MME).

Example 73 may include the method of any of examples 69 or 70 or any other example herein, wherein the access point is an evolved universal mobile

telecommunication system terrestrial radio access network (E-UTRAN) access point, and wherein the E-UTRAN access point is coupled to a fifth generation core network (5GC) and an evolved packet core (EPC).

Example 74 may include an apparatus to perform the method of any of examples 49-73 or some other example herein.

Example 75 may include one or more means to perform the method of any of examples 49-73 or some other example herein.

Example 76 may include one or more computer-readable media having instructions stored thereon, wherein the instructions, in response to execution by a device, cause the device to perform the method of any of the examples 49-73 or some other example herein.

It will be apparent to those skilled in the art that various modifications and variations can be made in the disclosed embodiments of the disclosed device and associated methods without departing from the spirit or scope of the disclosure. Thus, it is intended that the present disclosure covers the modifications and variations of the embodiments disclosed above provided that the modifications and variations come within the scope of any claims and their equivalents.