Patent Publication Number: US-2023156653-A1

Title: Network requested registration procedure initiation

Description:
BACKGROUND 
     Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features, and advantages of the enclosed embodiments will be apparent from the following description. 
     The current Third Generation Partnership Project (3GPP) Fifth Generation System (5GS) Non-Access Stratum (NAS) specification supports indication of network supported features from the network to the User Equipment (UE) to inform the UE of features that the UE can, and is allowed, to use. This indication of network supported features is signaled in the Registration procedure, which is a UE initiated procedure. In cases when the network needs to change the support of a feature for a specific UE, the Access and Mobility Management Function (AMF) can initiate a UE configuration update procedure and indicate a request for the UE to perform the Registration procedure. The request for registration can result in release of the current N1 NAS signaling connection for cases of AMF relocation, or with no N1 NAS signaling connection release, depending on setting of parameters and indications in the CONFIGURATION UPDATE COMMAND message. 
     SUMMARY 
     There currently exist certain challenge(s). When registration is requested via the UE configuration update procedure, the flag to indicate requested registration will result in N1 NAS signaling connection release unless an additional Information Element (IE) for the specific reason of requested registration is included. The only current such additional indication specified is Mobile Initiated Connection Only (MICO) indication. To support additional reasons for the network to request registration from UE, a new IE indicating the specific reason would need to be introduced, as use of the MICO specific indication would not be applicable. The more such reasons are possibly introduced in the future, the more IEs would be needed which would result in inefficient protocol design and larger message size, if no additional action is needed in the UE except registration procedure initiation. 
     Certain aspects of the present disclosure and their embodiments may provide solutions to the aforementioned or other challenges. Systems and methods are disclosed herein that provide, in the UE configuration update procedure, a generic indication to request a registration from a UE, while keeping the current N1 NAS signaling connection. In one embodiment, the indication is added in an existing IE with the requested registration. When the UE receives a CONFIGURATION UPDATE COMMAND message with registration indication and the new indication to keep the N1 NAS signaling connection, the UE initiates the registration procedure without release of the current N1 NAS signaling connection and no evaluation of specific network reasons to request the registration is needed. 
     There are, proposed herein, various embodiments which address one or more of the issues disclosed herein. 
     Certain embodiments may provide one or more of the following technical advantage(s). With a generic indication to keep the N1 NAS signaling connection at request of registration, no further new IE is needed. For any new case in the future to keep the N1 NAS signaling connection at request of registration, no new case specific IE is needed. The new flag can be used for all cases when the network needs to request registration without other specific action in the UE. Therefore, no reason specific IEs need to be defined and included in the CONFIGURATION UPDATE COMMAND message, reducing message size and specification complexity. In cases of more than one reason to request registration the benefit of a generic indication will be even bigger. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates one example of a cellular communications system  100  in which embodiments of the present disclosure may be implemented. 
         FIG.  2    illustrates a wireless communication system represented as a 5G network architecture, which can be viewed as one particular implementation of the system  100  of  FIG.  1   . 
         FIG.  3    illustrates a 5G network architecture using service-based interfaces between the NFs in the control plane. 
         FIG.  4    illustrates a UE configuration update procedure in accordance with one embodiment of the present disclosure. 
         FIG.  5    a schematic block diagram of a network node  500  according to some embodiments of the present disclosure. 
         FIG.  6    is a schematic block diagram that illustrates a virtualized embodiment of the network node  500  according to some embodiments of the present disclosure. 
         FIG.  7    is a schematic block diagram of the network node  500  according to some other embodiments of the present disclosure. 
         FIG.  8    is a schematic block diagram of a wireless communication device  800  according to some embodiments of the present disclosure. 
         FIG.  9    is a schematic block diagram of the wireless communication device  800  according to some other embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art. Additional information may also be found in the document(s) provided in the Appendix. 
     Radio Node: As used herein, a “radio node” is either a radio access node or a wireless communication device. 
     Radio Access Node: As used herein, a “radio access node” or “radio network node” or “radio access network node” is any node in a Radio Access Network (RAN) of a cellular communications network that operates to wirelessly transmit and/or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g., a New Radio (NR) base station (gNB) in a Third Generation Partnership Project (3GPP) Fifth Generation (5G) NR network or an enhanced or evolved Node B (eNB) in a 3GPP Long Term Evolution (LTE) network), a high-power or macro base station, a low-power base station (e.g., a micro base station, a pico base station, a home eNB, or the like), a relay node, a network node that implements part of the functionality of a base station (e.g., a network node that implements a gNB Central Unit (gNB-CU) or a network node that implements a gNB Distributed Unit (gNB-DU)) or a network node that implements part of the functionality of some other type of radio access node. 
     Core Network Node: As used herein, a “core network node” is any type of node in a core network or any node that implements a core network function. Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a Packet Data Network Gateway (P-GW), a Service Capability Exposure Function (SCEF), a Home Subscriber Server (HSS), or the like. Some other examples of a core network node include a node implementing a Access and Mobility Management Function (AMF), a User Plane Function (UPF), a Session Management Function (SMF), an Authentication Server Function (AUSF), a Network Slice Selection Function (NSSF), a Network Exposure Function (NEF), a Network Function (NF) Repository Function (NRF), a Policy Control Function (PCF), a Unified Data Management (UDM), or the like. 
     Communication Device: As used herein, a “communication device” is any type of device that has access to an access network. Some examples of a communication device include, but are not limited to: mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or Personal Computer (PC). The communication device may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and/or data via a wireless or wireline connection. 
     Wireless Communication Device: One type of communication device is a wireless communication device, which may be any type of wireless device that has access to (i.e., is served by) a wireless network (e.g., a cellular network). Some examples of a wireless communication device include, but are not limited to: a User Equipment device (UE) in a 3GPP network, a Machine Type Communication (MTC) device, and an Internet of Things (IoT) device. Such wireless communication devices may be, or may be integrated into, a mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or PC. The wireless communication device may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and/or data via a wireless connection. 
     Network Node: As used herein, a “network node” is any node that is either part of the RAN or the core network of a cellular communications network/system. 
     Note that the description given herein focuses on a 3GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system. 
     Note that, in the description herein, reference may be made to the term “cell”; however, particularly with respect to 5G NR concepts, beams may be used instead of cells and, as such, it is important to note that the concepts described herein are equally applicable to both cells and beams. 
     FIG.  1   
       FIG.  1    illustrates one example of a cellular communications system  100  in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communications system  100  is a 5G System (5GS). The 5GS includes 5G Core (5GC) and a Next Generation RAN (NG-RAN) including NR base stations (gNBs) and, optionally, next generation eNBs (ng-eNBs) (i.e., LTE RAN nodes connected to the 5GC). In this example, the RAN includes base stations  102 - 1  and  102 - 2 , which in the NG-RAN are referred to as gNBs (i.e., NR RAN nodes) or, optionally, ng-eNBs (i.e., LTE RAN nodes connected to the 5GC), controlling corresponding (macro) cells  104 - 1  and  104 - 2 . The base stations  102 - 1  and  102 - 2  are generally referred to herein collectively as base stations  102  and individually as base station  102 . Likewise, the (macro) cells  104 - 1  and  104 - 2  are generally referred to herein collectively as (macro) cells  104  and individually as (macro) cell  104 . The RAN may also include a number of low power nodes  106 - 1  through  106 - 4  controlling corresponding small cells  108 - 1  through  108 - 4 . The low power nodes  106 - 1  through  106 - 4  can be small base stations (such as pico or femto base stations) or Remote Radio Heads (RRHs), or the like. Notably, while not illustrated, one or more of the small cells  108 - 1  through  108 - 4  may alternatively be provided by the base stations  102 . The low power nodes  106 - 1  through  106 - 4  are generally referred to herein collectively as low power nodes  106  and individually as low power node  106 . Likewise, the small cells  108 - 1  through  108 - 4  are generally referred to herein collectively as small cells  108  and individually as small cell  108 . The cellular communications system  100  also includes a core network  110 , which in the 5GS is referred to as the 5G Core (5GC). The base stations  102  (and optionally the low power nodes  106 ) are connected to the core network  110 . 
     The base stations  102  and the low power nodes  106  provide service to wireless communication devices  112 - 1  through  112 - 5  in the corresponding cells  104  and  108 . The wireless communication devices  112 - 1  through  112 - 5  are generally referred to herein collectively as wireless communication devices  112  and individually as wireless communication device  112 . In the following description, the wireless communication devices  112  are oftentimes UEs, but the present disclosure is not limited thereto. 
     FIG.  2   
       FIG.  2    illustrates a wireless communication system represented as a 5G network architecture composed of core Network Functions (NFs), where interaction between any two NFs is represented by a point-to-point reference point/interface.  FIG.  2    can be viewed as one particular implementation of the system  100  of  FIG.  1   . 
     Seen from the access side the 5G network architecture shown in  FIG.  2    comprises a plurality of UEs  112  connected to either a RAN  102  or an Access Network (AN) as well as an Access and Mobility Management Function (AMF)  200 . Typically, the R(AN)  102  comprises base stations, e.g. such as eNBs or gNBs or similar. Seen from the core network side, the 5G core NFs shown in  FIG.  2    include a Network Slice Selection Function (NSSF)  202 , an Authentication Server Function (AUSF)  204 , a Unified Data Management (UDM)  206 , the AMF  200 , a Session Management Function (SMF)  208 , a Policy Control Function (PCF)  210 , and an Application Function (AF)  212 . 
     Reference point representations of the 5G network architecture are used to develop detailed call flows in the normative standardization. The N1 reference point is defined to carry signaling between the UE  112  and AMF  200 . The reference points for connecting between the AN  102  and AMF  200  and between the AN  102  and UPF  214  are defined as N2 and N3, respectively. There is a reference point, N11, between the AMF  200  and SMF  208 , which implies that the SMF  208  is at least partly controlled by the AMF  200 . N4 is used by the SMF  208  and UPF  214  so that the UPF  214  can be set using the control signal generated by the SMF  208 , and the UPF  214  can report its state to the SMF  208 . N9 is the reference point for the connection between different UPFs  214 , and N14 is the reference point connecting between different AMFs  200 , respectively. N15 and N7 are defined since the PCF  210  applies policy to the AMF  200  and SMF  208 , respectively. N12 is required for the AMF  200  to perform authentication of the UE  112 . N8 and N10 are defined because the subscription data of the UE  112  is required for the AMF  200  and SMF  208 . 
     The 5GC network aims at separating user plane and control plane. The user plane carries user traffic while the control plane carries signaling in the network. In  FIG.  2   , the UPF  214  is in the user plane and all other NFs, i.e., the AMF  200 , SMF  208 , PCF  210 , AF  212 , NSSF  202 , AUSF  204 , and UDM  206 , are in the control plane. Separating the user and control planes guarantees each plane resource to be scaled independently. It also allows UPFs to be deployed separately from control plane functions in a distributed fashion. In this architecture, UPFs may be deployed very close to UEs to shorten the Round Trip Time (RTT) between UEs and data network for some applications requiring low latency. 
     The core 5G network architecture is composed of modularized functions. For example, the AMF  200  and SMF  208  are independent functions in the control plane. Separated AMF  200  and SMF  208  allow independent evolution and scaling. Other control plane functions like the PCF  210  and AUSF  204  can be separated as shown in  FIG.  2   . Modularized function design enables the 5GC network to support various services flexibly. 
     Each NF interacts with another NF directly. It is possible to use intermediate functions to route messages from one NF to another NF. In the control plane, a set of interactions between two NFs is defined as service so that its reuse is possible. This service enables support for modularity. The user plane supports interactions such as forwarding operations between different UPFs. 
     FIG.  3   
       FIG.  3    illustrates a 5G network architecture using service-based interfaces between the NFs in the control plane, instead of the point-to-point reference points/interfaces used in the 5G network architecture of  FIG.  2   . However, the NFs described above with reference to  FIG.  2    correspond to the NFs shown in  FIG.  3   . The service(s) etc. that a NF provides to other authorized NFs can be exposed to the authorized NFs through the service-based interface. In  FIG.  3    the service based interfaces are indicated by the letter “N” followed by the name of the NF, e.g. Namf for the service based interface of the AMF  200  and Nsmf for the service based interface of the SMF  208 , etc. The Network Exposure Function (NEF)  300  and the Network Repository Function (NRF)  302  in  FIG.  3    are not shown in  FIG.  2    discussed above. However, it should be clarified that all NFs depicted in  FIG.  2    can interact with the NEF  300  and the NRF  302  of  FIG.  3    as necessary, though not explicitly indicated in  FIG.  2   . 
     Some properties of the NFs shown in  FIGS.  2  and  3    may be described in the following manner. The AMF  200  provides UE-based authentication, authorization, mobility management, etc. A UE  112  even using multiple access technologies is basically connected to a single AMF  200  because the AMF  200  is independent of the access technologies. The SMF  208  is responsible for session management and allocates Internet Protocol (IP) addresses to UEs. It also selects and controls the UPF  214  for data transfer. If a UE  112  has multiple sessions, different SMFs  208  may be allocated to each session to manage them individually and possibly provide different functionalities per session. The AF  212  provides information on the packet flow to the PCF  210  responsible for policy control in order to support Quality of Service (QoS). Based on the information, the PCF  210  determines policies about mobility and session management to make the AMF  200  and SMF  208  operate properly. The AUSF  204  supports authentication function for UEs or similar and thus stores data for authentication of UEs or similar while the UDM  206  stores subscription data of the UE  112 . The Data Network (DN), not part of the 5GC network, provides Internet access or operator services and similar. 
     An NF may be implemented either as a network element on a dedicated hardware, as a software instance running on a dedicated hardware, or as a virtualized function instantiated on an appropriate platform, e.g., a cloud infrastructure. 
     FIG.  4   
     Embodiments of the present disclosure will now be described in detail. In this regard,  FIG.  4    illustrates a UE configuration update procedure in accordance with one embodiment of the present disclosure. As illustrated, the AMF  200  sends a configuration update command to the UE  112  (step  400 ). In one embodiment, the AMF  200  starts a timer (T3555) upon sending the configuration update command. The UE  112  performs one or more actions in accordance with the configuration update command (step  402 ). In one embodiment, the UE  112  sends a configuration update complete message to the AMF  200  (step  404 ). In one embodiment, the AMF  200  stops the timer (T3555) upon receiving the configuration update complete message. However, as illustrated, in another embodiment, the AMF  200  sends the configuration update command to the UE  112  in step  400 , but the UE  112  does not send a configuration update complete message to the AMF  200 , nor does the AMF  200  start or stop the timer. 
     In accordance with one embodiment of the present disclosure, the configuration update command of step  400  includes an indication that indicates, to the UE  112 , whether the UE  112  is to maintain the existing N1 NAS signaling connection. For example, the indication may be a single bit that indicates that the existing N1 NAS signaling connection is required to be released if the single bit indication is set to one binary value (e.g., “0”) and is not required to be released if the single bit indication is set to the other binary value (e.g., “1”). In one embodiment, the indication is a generic indication in that the indication is applicable regardless of the reason for the configuration update command. In one embodiment, the indication that indicates whether the UE  112  is to maintain the existing N1 NAS signaling connection is included in a configuration update indication IE included in the configuration update command. 
     In one embodiment, the configuration update command of step  400  includes both a registration request and the indication that indicates, to the UE  112 , whether the UE  112  is to maintain the existing N1 NAS signaling connection. Together, the registration request and the indication indicate, to the UE  112 , that the UE  112  is to perform a registration procedure and that the UE  112  is or is not to maintain the existing N1 NAS signaling connection at the requested registration. In one embodiment, the registration request and the indication that indicates whether the UE  112  is to maintain the existing N1 NAS signaling connection are both included in a configuration update indication IE included in the configuration update command. 
     The one or more actions performed by the UE  112  in step  402  include releasing or refraining from releasing the existing N1 NAS signaling connection, in accordance with the indication included in the configuration update command. In addition, if the configuration update command includes a request for the UE  112  to perform the registration procedure, the UE  112  performs the registration procedure (with or without releasing the existing N1 NAS signaling connection in accordance with the indication) in accordance with the request. 
     The currently specified way to request registration using the UE configuration update procedure for change of MICO mode is achieved by a combination of the registration requested flag (RED) in the configuration update indication IE included in the configuration update command and inclusion of the MICO indication IE in the configuration update command as follows: 
     
       
         
           
               
               
               
               
               
               
             
               
                   
               
             
            
               
                 Configuration update 
                 0 
                 0 
                 RED 
                 ACK 
                 octet 1 
               
               
                 indication IEI 
                 Spare 
                 Spare 
               
               
                   
               
            
           
         
       
     
     Registration Requested (RED) (Octet 1, Bit 2): 
       
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 0 
                 registration not requested 
               
               
                 1 
                 registration requested 
               
               
                   
               
            
           
         
       
     
                                                    MICO indication IEI   0   0   SPRTI   RAAI   octet 1           Spare   Spare                    
Note that the contents of the MICO indication IE are not significant for the use in the UE configuration update procedure as it is the presence only that is evaluated.
 
     To support other cases of requested registration via the UE configuration update procedure where no N1 NAS signaling connection release is desired or required and no other case specific action is needed in the UE  112 , in one embodiment of the present disclosure, a new flag is defined using one of the spare bits in the configuration update indication IE. For example, the new flag, referred to as Signaling Connection Release Request (SCRR), may be provided as follows: 
     
       
         
           
               
               
               
               
               
               
             
               
                   
               
             
            
               
                 Configuration update 
                 0 
                 SCRR 
                 RED 
                 ACK 
                 octet 1 
               
               
                 indication IEI 
                 Spare 
               
               
                   
               
            
           
         
       
     
     Signaling Connection Release Request (SCRR) (Octet 1, Bit 3) 
       
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 0 
                 Release of N1 NAS signaling connection required 
               
               
                 1 
                 Release of N1 NAS signaling connection not required 
               
               
                   
               
            
           
         
       
     
     In one example alternative embodiment, a new optional IE can be defined. For example, in this example alternative embodiment, the new optional IE is referred to herein as a configuration update parameters IE and can be defined as follows: 
     
       
         
           
               
               
               
               
               
               
             
               
                   
               
             
            
               
                 Configuration update 
                 0 
                 0 
                 0 
                 SCRR 
                 octet 1 
               
               
                 parameters IEI 
                 Spare 
                 Spare 
                 Spare 
               
               
                   
               
            
           
         
       
     
     Signaling Connection Release Request (SCRR) (Octet 1, Bit 1) 
       
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 0 
                 Release of N1 NAS signaling connection required 
               
               
                 1 
                 1 Release of N1 NAS signaling connection not required 
               
               
                   
               
            
           
         
       
     
     Common for both protocol implementation alternatives described above is that the flag (SCRR) is not tied to a specific case, but can be used by the network when a subsequent execution of a registration procedure is sufficient for the specific use case at hand. 
     Further details of one example embodiment of the proposed protocol solution are provided in the attached draft Change Request (CR) for 3GPP TS 24.501. 
     FIG.  5   
       FIG.  5    is a schematic block diagram of a network node  500  according to some embodiments of the present disclosure. Optional features are represented by dashed boxes. The network node  500  may be, for example, a network node that implements the AMF  200  or implements at least some of the functionality of the AMF  200  described herein. As illustrated, the network node  500  includes one or more processors  504  (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and/or the like), memory  506 , and a network interface  508 . The one or more processors  504  are also referred to herein as processing circuitry. The one or more processors  504  operate to provide one or more functions of the network node  500  as described herein (e.g., one or more functions of the AMF  200  described herein, e.g., with respect to  FIG.  4   ). In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory  506  and executed by the one or more processors  504 . 
     FIG.  6   
       FIG.  6    is a schematic block diagram that illustrates a virtualized embodiment of the network node  500  according to some embodiments of the present disclosure. As used herein, a “virtualized” network node is an implementation of the network node  500  in which at least a portion of the functionality of the network node  500  is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the network node  500  includes one or more processing nodes  600  coupled to or included as part of a network(s)  602 . Each processing node  600  includes one or more processors  604  (e.g., CPUs, ASICs, FPGAs, and/or the like), memory  606 , and a network interface  608 . In this example, functions  610  of the network node  500  described herein (e.g., one or more functions of the AMF  200  described herein, e.g., with respect to  FIG.  4   ) are implemented at the one or more processing nodes  600  or distributed across the two or more of the processing nodes  600  in any desired manner. In some particular embodiments, some or all of the functions  610  of the network node  500  described herein (e.g., one or more functions of the AMF  200  described herein, e.g., with respect to  FIG.  4   ) are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s)  600 . 
     In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the network node  500  or a node (e.g., a processing node  600 ) implementing one or more of the functions  610  of the network node  500  in a virtual environment according to any of the embodiments described herein (e.g., one or more functions of the AMF  200  described herein, e.g., with respect to  FIG.  4   ) is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory). 
     FIG.  7   
       FIG.  7    is a schematic block diagram of the network node  500  according to some other embodiments of the present disclosure. The network node  500  includes one or more modules  700 , each of which is implemented in software. The module(s)  700  provide the functionality of the network node  500  described herein (e.g., one or more functions of the AMF  200  described herein, e.g., with respect to  FIG.  4   ). This discussion is equally applicable to the processing node  600  of  FIG.  6    where the modules  700  may be implemented at one of the processing nodes  600  or distributed across two or more of the processing nodes  600 . 
     FIG.  8   
       FIG.  8    is a schematic block diagram of a wireless communication device  800  according to some embodiments of the present disclosure. The wireless communication device  800  may be the UE  112  described above. As illustrated, the wireless communication device  800  includes one or more processors  802  (e.g., CPUs, ASICs, FPGAs, and/or the like), memory  804 , and one or more transceivers  806  each including one or more transmitters  808  and one or more receivers  810  coupled to one or more antennas  812 . The transceiver(s)  806  includes radio-front end circuitry connected to the antenna(s)  812  that is configured to condition signals communicated between the antenna(s)  812  and the processor(s)  802 , as will be appreciated by on of ordinary skill in the art. The processors  802  are also referred to herein as processing circuitry. The transceivers  806  are also referred to herein as radio circuitry. In some embodiments, the functionality of the wireless communication device  800  described above (e.g., one or more functions of the UE  112  described herein, e.g., with respect to  FIG.  4   ) may be fully or partially implemented in software that is, e.g., stored in the memory  804  and executed by the processor(s)  802 . Note that the wireless communication device  800  may include additional components not illustrated in  FIG.  8    such as, e.g., one or more user interface components (e.g., an input/output interface including a display, buttons, a touch screen, a microphone, a speaker(s), and/or the like and/or any other components for allowing input of information into the wireless communication device  800  and/or allowing output of information from the wireless communication device  800 ), a power supply (e.g., a battery and associated power circuitry), etc. 
     In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the wireless communication device  800  according to any of the embodiments described herein (e.g., one or more functions of the AMF  200  described herein, e.g., with respect to  FIG.  4   ) is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory). 
     FIG.  9   
       FIG.  9    is a schematic block diagram of the wireless communication device  800  according to some other embodiments of the present disclosure. The wireless communication device  800  includes one or more modules  900 , each of which is implemented in software. The module(s)  900  provide the functionality of the wireless communication device  800  described herein (e.g., one or more functions of the AMF  200  described herein, e.g., with respect to  FIG.  4   ). 
     Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure. 
     While processes in the figures may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.). 
     SOME EMBODIMENTS 
     Some embodiments that are disclosed above may be summarized in the following manner: 
     1. A method performed by a wireless communication device ( 112 ), the method comprising: 
     receiving ( 400 ), from a network node ( 200 ), a configuration update command comprising an indication as to whether the wireless communication device ( 112 ) is to maintain an existing non-access stratum, NAS, connection; and 
     performing ( 402 ) one or more actions in accordance with the configuration update command. 
     2. The method of embodiment 1 wherein the existing NAS connection is an existing N1 NAS connection of the wireless communication device ( 112 ).
 
3. The method of embodiment 1 or 2 wherein performing ( 402 ) the one or more actions comprise releasing or refraining from releasing the existing NAS connection in accordance with the indication.
 
4. The method of any of embodiments 1 to 3 wherein the indication is a one-bit indication that indicates that the wireless communication device ( 112 ) is required to release the existing NAS connection if set to a first binary value and indicates that the wireless communication device ( 112 ) is not required to release the existing NAS connection if set to a second binary value.
 
5. The method of any of embodiments 1 to 4 wherein the configuration update command further comprises information that indicates, to the wireless communication device ( 112 ), that the wireless communication device ( 112 ) is to perform a registration procedure.
 
6. The method of embodiment 5 wherein performing ( 402 ) the one or more actions comprise performing the registration procedure and releasing or refraining from releasing the existing NAS connection in accordance with the indication when performing the registration procedure.
 
7. The method of any of embodiments 1 to 6 wherein the indication is a general indication that is applicable to two or more reasons for the configuration update command.
 
8. The method of any of embodiments 1 to 7 wherein the indication is comprised in a configuration update indication information element comprised in the configuration update command.
 
9. The method of embodiment 8 wherein the indication is a one-bit indication comprised in either bit 3 or bit 4 of octet 1 of the configuration update indication information element.
 
10. The method of any of embodiments 1 to 7 wherein the indication is comprised in an information element, other than a configuration update indication information element, comprised in the configuration update command.
 
11. The method of any of embodiments 1 to 10 wherein the network node ( 200 ) is an Access and Mobility Management Function, AMF, ( 200 ).
 
12. A wireless communication device ( 112 ) adapted to:
 
     receive ( 400 ), from a network node ( 200 ), a configuration update command comprising an indication as to whether the wireless communication device ( 112 ) is to maintain an existing non-access stratum, NAS, connection; and 
     perform ( 402 ) one or more actions in accordance with the configuration update command. 
     13. The wireless communication device ( 112 ) of embodiment 12 wherein the wireless communication device ( 112 ) is further adapted to perform the method of any of embodiments 2 to 11.
 
14. The wireless communication device ( 112 ) of embodiment 12 or 13 wherein the wireless communication device ( 112 ) comprises:
 
     one or more transmitters ( 808 ); 
     one or more receivers ( 810 ); and 
     processing circuitry ( 802 ) associated with the one or more transmitters ( 808 ) and the one or more receivers ( 810 ), the processing circuitry ( 802 ) configured to cause the wireless communication device ( 112 ) to:
         receive ( 400 ) the configuration update command from the network node ( 200 ); and   perform ( 402 ) the one or more actions in accordance with the configuration update command.
 
15. A method performed by a network node ( 200 ) of a wireless communication system ( 100 ), the method comprising:
       

     sending ( 400 ), to a wireless communication device ( 112 ), a configuration update command comprising an indication as to whether the wireless communication device ( 112 ) is to maintain an existing non-access stratum, NAS, connection. 
     16. The method of embodiment 15 wherein the existing NAS connection is an existing N1 NAS connection of the wireless communication device ( 112 ).
 
17. The method of any of embodiments 15 to 16 wherein the indication is a one-bit indication that indicates that the wireless communication device ( 112 ) is required to release the existing NAS connection if set to a first binary value and indicates that the wireless communication device ( 112 ) is not required to release the existing NAS connection if set to a second binary value.
 
18. The method of any of embodiments 15 to 17 wherein the configuration update command further comprises information that indicates, to the wireless communication device ( 112 ), that the wireless communication device ( 112 ) is to perform a registration procedure.
 
19. The method of any of embodiments 15 to 18 wherein the indication is a general indication that is applicable to two or more reasons for the configuration update command.
 
20. The method of any of embodiments 15 to 18 wherein the indication is comprised in a configuration update indication information element comprised in the configuration update command.
 
21. The method of embodiment 20 wherein the indication is a one-bit indication comprised in either bit 3 or bit 4 of octet 1 of the configuration update indication information element.
 
22. The method of any of embodiments 15 to 18 wherein the indication is comprised in an information element, other than a configuration update indication information element, comprised in the configuration update command.
 
23. The method of any of embodiments 15 to 22 wherein the network node ( 200 ) is an Access and Mobility Management Function, AMF, ( 200 ).
 
24. A network node ( 200 ) of a wireless communication system ( 100 ), the network node ( 200 ) adapted to:
 
     send ( 400 ), to a wireless communication device ( 112 ), a configuration update command comprising an indication as to whether the wireless communication device ( 112 ) is to maintain an existing non-access stratum, NAS, connection. 
     25. The network node ( 200 ) of embodiment 24 wherein the network node ( 200 ) is further adapted to perform the method of any of embodiments 16 to 23.
 
26. The network node ( 200 ) of embodiment 24 or 25 wherein the network node ( 200 ) comprises processing circuitry ( 504 ;  604 ) configured to cause the network node ( 200 ) to send ( 400 ) the configuration update command to the wireless communication device ( 112 ).
 
     Abbreviations 
     At least some of the following abbreviations may be used in this disclosure. If there is an inconsistency between abbreviations, preference should be given to how it is used above. If listed multiple times below, the first listing should be preferred over any subsequent listing(s).
         3GPP Third Generation Partnership Project   5G Fifth Generation   5GC Fifth Generation Core   5GS Fifth Generation System   AF Application Function   AMF Access and Mobility Management Function   AN Access Network   AUSF Authentication Server Function   DN Data Network   eNB Enhanced or Evolved Node B   EPC Evolved Packet Core   E-UTRA Evolved Universal Terrestrial Radio Access   gNB New Radio Base Station   HSS Home Subscriber Server   IoT Internet of Things   IP Internet Protocol   LTE Long Term Evolution   MME Mobility Management Entity   MTC Machine Type Communication   NEF Network Exposure Function   NF Network Function   NR New Radio   NRF Network Function Repository Function   NSSF Network Slice Selection Function   PCF Policy Control Function   P-GW Packet Data Network Gateway   QoS Quality of Service   RAN Radio Access Network   SCEF Service Capability Exposure Function   SMF Session Management Function   UDM Unified Data Management   UE User Equipment   UPF User Plane Function