Deterministic PLMN selection during disaster roaming

Abstract

The present application generally relates to deterministic PLMN selection during disaster roaming. The present application provides systems and methods for public land mobile network (PLMN) selection for disaster roaming. A user equipment (UE) determines a disaster situation at a first PLMN, wherein the UE is a subscriber to the first PLMN. The UE determines the availability of a second PLMN for disaster roaming. The UE selects the second PLMN and attempts to register for disaster roaming on the second PLMN. In response to attempting to register for disaster roaming on the second PLMN, the UE receives a registration reject message including a cause value corresponding to a registration failure for disaster roaming on the second PLMN due to the disaster situation on the first PLMN. The UE waits for a first time period before again attempting to register for disaster roaming on the second PLMN for the first PLMN having the disaster situation.

Description

Technical Field

[0001] The present application relates generally to wireless communication systems, including public land mobile network (PLMN) selection during disaster roaming. Background Art

[0002] Wireless mobile communication technologies use various standards and protocols to transmit data between base stations and wireless communication devices. Wireless communication system standards and protocols may include, for example, the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) (e.g., 4G), 3GPP New Radio (NR) (e.g., 5G), and the IEEE 802.11 standard for wireless local area networks (WLANs) (commonly referred to within industry organizations as WLANs). ).

[0003] As envisioned by 3GPP, different wireless communication system standards and protocols may use various radio access networks (RANs) to enable base stations of the RAN (which may also sometimes be referred to as RAN nodes, network nodes, or simply nodes) to communicate with wireless communication devices, referred to as user equipment (UE). 3GPP RANs may include, for example, Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE) RAN (GERAN), Universal Terrestrial Radio Access Network (UTRAN), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and / or Next Generation Radio Access Network (NG-RAN).

[0004] Each RAN can use one or more radio access technologies (RATs) for communication between base stations and UEs. For example, GERAN implements GSM and / or EDGE RATs, UTRAN implements Universal Mobile Telecommunications System (UMTS) RATs or other 3GPP RATs, E-UTRAN implements LTE RATs (sometimes referred to as LTE), and NG-RAN implements NR RATs (sometimes also referred to herein as 5G RATs, 5G NRRATs, or simply NR). In some deployments, E-UTRAN may also implement NRRATs. In some deployments, NG-RAN may also implement LTE RATs.

[0005] The base station used by the RAN may correspond to the RAN. An example of an E-UTRAN base station is an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (often also denoted as an evolved Node B, enhanced Node B, eNodeB, or eNB). An example of an NG-RAN base station is a Next Generation Node B (sometimes also referred to as a gNodeB or gNB).

[0006] The RAN provides communication services together with external entities through its connection with the Core Network (CN). For example, E-UTRAN can utilize the Evolved Packet Core (EPC), while NG-RAN can utilize the 5G Core (5GC). Summary of the Invention

[0007] According to one aspect of the present disclosure, a method for a user equipment (UE) to perform public land mobile network (PLMN) selection for disaster roaming is provided, the method comprising: determining a disaster situation at a first PLMN, wherein the UE is a subscriber of the first PLMN; determining the availability of a second PLMN for the disaster roaming; selecting the second PLMN and attempting to register for the disaster roaming on the second PLMN; in response to attempting to register for the disaster roaming on the second PLMN, receiving a registration rejection message including a cause value, the cause value corresponding to a registration failure for the disaster roaming on the second PLMN due to the disaster situation on the first PLMN; and waiting for a first time period before again attempting to register for the disaster roaming on the second PLMN for the first PLMN having the disaster situation.

[0008] According to another aspect of the present disclosure, a method for a network device for a disaster situation at a first public land mobile network (PLMN) is provided, the method comprising: in response to a failure of a user equipment (UE) to register for disaster roaming for the first PLMN on a second PLMN, generating a registration reject message including a cause value, the cause value corresponding to the registration failure for the disaster roaming on the second PLMN due to the disaster situation on the first PLMN; and sending the registration reject message including the cause value to the UE, the cause value corresponding to the registration failure for the disaster roaming.

[0009] According to another aspect of the present disclosure, a computer program product is provided comprising instructions, which implement the steps of the aforementioned method when executed by a processor.

[0010] According to another aspect of the present disclosure, a device is provided, comprising means for implementing the steps of the aforementioned method. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] To easily identify the discussion of any particular element or act, the most significant digit(s) in a reference number refers to the drawing number that first introduces the element.

[0012] Figure 1 A flow chart illustrating a possible deadlock cycle during UE selection of a PLMN in a disaster situation.

[0013] Figure 2 A flow chart illustrating an implementation of UE authorization selection using a disaster roaming attempt counter and an implementation-specific timer according to one embodiment is shown.

[0014] Figure 3 A flow chart illustrating an implementation of UE authorization selection using a disaster roaming attempt counter, an implementation-specific timer, and a cause value according to one embodiment is shown.

[0015] Figure 4 A method for a UE to perform PLMN selection for disaster roaming according to one embodiment is shown.

[0016] Figure 5 A method for a network device in a disaster situation at a first PLMN is shown according to one embodiment.

[0017] Figure 6 An exemplary architecture of a wireless communication system according to embodiments disclosed herein is shown.

[0018] Figure 7 A system for performing signaling between a wireless device and a network device according to embodiments disclosed herein is shown.

[0019] Figure 8 An exemplary service-based architecture is shown in accordance with certain embodiments. DETAILED DESCRIPTION

[0020] The various embodiments are described with respect to a UE. However, reference to a UE is provided for illustrative purposes only. The exemplary embodiments may be used with any electronic component that can establish a connection with a network and is configured with hardware, software, and / or firmware for exchanging information and data with the network. Therefore, as described herein, a UE is used to represent any suitable electronic component.

[0021] As anticipated by 3GPP, a UE can connect to a public land mobile network (PLMN) for various connectivity services. In some cases, while connected to the selected PLMN, the UE's registration with the selected PLMN may fail. For example, the UE may be a subscriber to PLMN D and attempt to register with PLMN D, but registration may fail due to a disaster situation. For example, the UE may determine a disaster situation on PLMN D when it fails to detect any cells of PLMN D and discovers that another PLMN indicates that it is providing disaster roaming for PLMN D.

[0022] In disaster roaming, the UE may attempt to register with an alternative PLMN by performing a PLMN search and selecting the alternative PLMN based on the UE's defined PLMN priority information. Due to the disaster situation, the UE may select an alternative PLMN from its forbidden PLMN list or a list of PLMNs with forbidden tracking areas (TAs). A particular PLMN may be in the UE's forbidden PLMN list or list of PLMNs with forbidden TAs, for example, if indicated by the UE's subscription or home PLMN (e.g., the home PLMN does not have a roaming agreement with the particular PLMN), or the UE adds the particular PLMN to the list after attempting to register with the particular PLMN but failing. The UE's forbidden PLMN list or list of PLMNs with forbidden TAs may be maintained for a period of time (e.g., 12 hours or 24 hours) and then refreshed so the UE can attempt to register later.

[0023] For example, a UE may be a subscriber to PLMN D. Due to a disaster situation, the UE may not be able to successfully connect to PLMN D. Alternatively, PLMN D may provide a notification that it is unavailable due to the disaster situation. PLMN A may be on the UE's forbidden PLMN list or a list of PLMNs with forbidden TAs. However, when other PLMNs are unavailable, the UE may select PLMN A, which provides disaster roaming for subscribers of PLMN D. The UE indicates to PLMN A that it has selected PLMN A for disaster roaming due to the disaster situation on PLMN D. PLMN A may authenticate the UE by contacting the Authentication Server Function (AUSF) and / or Unified Data Manager Function (UDM) of PLMN D. If authentication is successful, the UE receives normal service on PLMN A. However, if authentication is unsuccessful, PLMN A may deny the UE registration; for example, the UE may receive a Registration Reject message with Cause #11 (Forbidden PLMN) or Cause #13 (Forbidden TA). Alternatively, if authentication is unsuccessful, the UE may continue searching for another PLMN. It is worth noting that 3GPP does not define a cause value to describe Minimization of Service Interruption (MINT) registration failures.

[0024] Various embodiments for configuring a UE to allow deterministic PLMN selection are described herein. Utilizing one or more of these embodiments can facilitate a more efficient UE registration process with a PLMN and reduce network load.

[0025] In the event of an authentication failure, the UE PLMN selection may enter a repeated PLMN selection cycle, which may cause network overload. Authentication failure may occur for various reasons, including but not limited to the selected PLMN (e.g., PLMN A) being temporarily overloaded due to signaling, the UE roaming or moving out of the registration area and / or the subscriber's PLMN being temporarily unavailable for authentication. According to the 3GPP definition, the UE places the PLMN with the authentication failure on a forbidden PLMN list or a forbidden TA list. If no other PLMN is available, the UE may try to register with PLMN A again. Therefore, as described below with respect to Figure 1 As discussed above, the UE may enter a PLMN selection loop that may cause network overload. Furthermore, during disaster situations, the UE may be out of service for an extended period of time.

[0026] Figure 1 A flowchart 100 illustrates a possible deadlock loop during UE selection of a PLMN in a disaster situation. In one example of a deadlock, at block 102, the UE may use PLMN D. As in the example above, the UE is a subscriber to PLMN D. PLMN D may be experiencing a disaster situation and unavailable for connection to the UE, causing the UE to perform PLMN selection at block 104. If, at decision block 106, a forbidden PLMN is available (i.e., the UE detects that a cell in PLMN A is providing disaster roaming for PLMN D), the UE selects the forbidden PLMN A at block 110. The UE then attempts to register with PLMN A at block 112, and PLMN A attempts to authenticate the UE. If PLMN authentication is unsuccessful at block 112, the UE receives a registration reject message, returns to PLMN selection at block 104, and attempts to select a PLMN again. As shown, the UE may continue in this loop.

[0027] Alternatively, at block 102, the UE may use PLMN D. The PLMN may encounter a disaster situation, necessitating the UE to perform PLMN selection at block 104. If the prohibited PLMN is not available at decision block 106, the UE determines whether a PLMN with a prohibited TA is available at decision block 108. If the PLMN with a prohibited TA is not available, the UE returns to PLMN selection at block 104 and attempts to select a PLMN again. As shown, the UE may continue to operate in this loop.

[0028] Alternatively, at block 102, the UE may use PLMN D. The PLMN may encounter a disaster situation, necessitating PLMN selection by the UE at block 104. If a prohibited PLMN is not available at decision block 106, the UE determines whether a PLMN with a prohibited TA is available at decision block 108. If PLMN A with a prohibited TA is available, the UE selects the prohibited PLMN A at block 110. The UE then attempts to register with PLMN A at block 112, and PLMN A attempts to authenticate the UE. If PLMN authentication is unsuccessful at block 112, the UE receives a registration rejection message, returns to PLMN selection at block 104, and attempts to select a PLMN again. As shown, the UE may continue to operate in this loop.

[0029] If authentication at block 112 is successful, the UE may be communicatively connected to PLMN A at block 114 .

[0030] like Figure 1 As shown, if PLMN selection is repeatedly unsuccessful at decision block 108 or authentication of the UE is repeatedly unsuccessful at block 112, the UE's selection of a PLMN during PLMN selection may result in a deadlock loop.

[0031] According to certain embodiments, it may be advantageous for the UE to continue attempting to connect to PLMN A under certain conditions. For example, if PLMN A still indicates that it provides disaster roaming and the UE's subscribed PLMN D has experienced a disaster situation, the UE may continue attempting to connect to PLMN A. In some cases, registration failure may be due to transient conditions, and continuing to attempt authentication at PLMN A may be preferable. As a safeguard, the network may optionally limit the time within which the UE can initiate the registration process when it reaches PLMN A in the absence of a disaster situation. In some embodiments, these limits may be signaled, preconfigured, or calculated at the UE. Whether these limits are signaled, preconfigured, or calculated at the UE may be decided during the specification phase (e.g., based on signaled or preconfigured parameters). The UE may attach an implementation-specific timer before retrying authentication on the PLMN.

[0032] To overcome deadlock cycles and / or other inefficiencies during PLMN selection, in one embodiment, the UE maintains another list of PLMNs for which registration failed due to disaster roaming (i.e., a prohibited PLMN list and / or a list of PLMNs with prohibited TAs). In some embodiments, this list may be referred to as a disaster roaming failure list. Before retrying authentication on a PLMN in the disaster roaming failure list for a disaster situation on a different PLMN (e.g., PLMN E or PLMN F), the UE attaches or starts an implementation-specific timer. The implementation-specific timer may be several minutes to several hours. In one example, the implementation-specific timer is in the range of 3 minutes to 10 minutes, i.e., after a registration failure for disaster roaming due to a disaster situation on PLMN D, the UE waits to attempt registration on a PLMN in the disaster roaming failure list due to a disaster situation on another PLMN (e.g., PLMN E or PLMN F).

[0033] In certain embodiments, the Access and Mobility Management Function (AMF) may provide a new 5G System (5GS) Mobility Management (5GMM) cause value when rejecting a registration request. For example, the AMF may provide a registration reject message including a cause value corresponding to a registration failure for disaster roaming on PLMN A due to a disaster situation on PLMN D. In certain such embodiments, the AMF may also provide an indication of the registration failure type to indicate whether the failure is temporary (and may optionally include a waiting time) or whether the failure is permanent (no waiting time is specified). For example, the indicated waiting time may be in the range of 12 hours and 24 hours before the UE attempts to register for disaster roaming on PLMN A due to the disaster situation on PLMN D. In certain embodiments, if the AMF indicates that PLMN A has failed permanently, the UE may proceed with PLMN selection if PLMN A has been assigned the lowest priority.

[0034] In another embodiment, a disaster roaming registration failure counter may be used. The UE increments the disaster roaming registration failure counter for each disaster roaming registration failure and uses the disaster roaming registration failure counter to stagger registration attempts. For example, the UE may calculate a series of time windows for attempting registration at a PLMN (e.g., PLMN A). The series of time windows may be adjusted by an initial start time. In the event of a registration failure, subsequent registration attempts may be subject to an additional offset time that may be increased proportionally based on the disaster roaming registration failure counter. In other embodiments, the UE may use a hash of the International Mobile Subscriber Identity (IMSI) and a random number (or pseudo-random number) to generate a disaster roaming waiting range. If the disaster roaming registration failure counter is non-zero, the waiting range may be increased proportionally. As another example, the UE may be subject to a minimum waiting time that is increased proportionally based on the disaster roaming registration failure counter (if the disaster roaming registration failure counter is non-zero). As another example, the UE may increment the disaster roaming registration failure counter until a threshold is met. If the threshold is not met, the UE may continue to attempt to register with the PLMN.

[0035] Figure 2 A flowchart 200 illustrating an implementation of UE authorization selection using a disaster roaming attempt counter and an implementation-specific timer according to one embodiment is shown. The disaster roaming attempt counter is also referred to herein as a disaster roaming registration failure counter.

[0036] like Figure 2As shown, at block 202, the UE may use PLMN D. The UE is a subscriber to PLMN D. PLMN D may be experiencing a disaster situation and unavailable to the UE. In response, at block 204, the UE performs PLMN selection. If the prohibited PLMN is unavailable at decision block 206, the UE determines whether a PLMN with a prohibited TA is available at decision block 208. If the PLMN with a prohibited TA is unavailable, the UE returns to PLMN selection at block 204 and attempts to select a PLMN again. If a PLMN with a prohibited TA is available, the UE selects PLMN A at block 210. Alternatively, if the prohibited PLMN is available at decision block 206, the UE selects PLMN A at block 210. Then, at block 212, the UE attempts to register with PLMN A, and PLMN A attempts to authenticate the UE. If PLMN authentication is unsuccessful at block 212, the UE utilizes a disaster roaming attempt counter at decision block 216. As previously described, the UE may increment the disaster roaming attempt counter for each disaster roaming registration failure. If the disaster roaming counter has not reached the maximum count (i.e., the maximum number of times), the UE may wait for an implementation-specific amount of time at block 214 before making another authentication request with PLMN A at block 212. If the disaster roaming attempt counter has reached the maximum count, the UE returns to PLMN selection at block 204 and attempts to select a PLMN again.

[0037] If the authentication at block 212 is successful, then at block 218 the UE uses PLMN A for disaster roaming.

[0038] Those skilled in the art will appreciate that the steps of flowchart 200 need not be performed in a particular order and that the concepts described can still be embodied when performed in another order or when the steps are not utilized. For example, decision block 206 and decision block 208 can be swapped. As another example, decision block 206 or decision block 208 can be removed entirely. As another example, block 204 can be replaced by another type of PLMN selection.

[0039] like Figure 2 As shown, adding the disaster roaming decision block 216 and the implementation-specific waiting time block 214 can provide the UE with a solution to select a PLMN in a deterministic manner. Figure 1 One way to avoid a deadlock loop during UE selection is shown. This selection method can provide higher efficiency, generate less network load, and provide more reliable services.

[0040] Figure 3300 is a flowchart of an implementation of UE authorization selection using a disaster roaming attempt counter, an implementation-specific timer, and a new 5GMM cause value corresponding to a disaster roaming registration failure. The disaster roaming attempt counter is also referred to herein as a disaster roaming registration failure counter.

[0041] In one embodiment, at block 302, the UE may use PLMN D. As in the example above, the UE is a subscriber to PLMN D. The PLMN may experience a disaster and become unavailable to the UE. In response, at block 304, the UE performs PLMN selection. If the prohibited PLMN is unavailable at decision block 306, the UE determines whether a PLMN with a prohibited TA is available at decision block 308. If a PLMN with a prohibited TA is unavailable, the UE returns to PLMN selection at block 304 and attempts to select a PLMN again at block 304. However, if the prohibited PLMN is available at decision block 306, the UE selects PLMN A at block 310. Alternatively, if the prohibited PLMN is available at decision block 306, the UE selects PLMN A at block 310. Then, at block 312, the UE attempts to register with PLMN A, and PLMN A attempts to authenticate the UE. Authentication may or may not be successful. If the authentication is unsuccessful, the UE receives (e.g., from the AMF) a Registration Reject message including a cause value corresponding to registration failure for disaster roaming on PLMN A due to a disaster situation on PLMN D.

[0042] In certain embodiments, if the PLMN A authentication registration request is rejected due to a temporary failure, the UE increments the disaster roaming attempt counter at decision block 316. As described above, the UE may increment the disaster roaming attempt counter for each disaster roaming registration failure. If the disaster roaming attempt counter has not reached a threshold (i.e., a maximum number of times), the UE may wait for a period of time based on a network-based wait time at block 314 before making another authentication request for PLMN A at block 312. If the PLMN A authentication registration request is rejected due to a temporary failure and the disaster roaming attempt counter has reached the threshold, the UE returns to PLMN selection at block 304 and attempts to select a PLMN again. Alternatively, if the PLMN A authentication registration request is rejected due to a permanent failure, the UE assigns the lowest (or lower) priority to PLMN A at block 320 and attempts to select a PLMN again at block 304.

[0043] If authentication at block 312 is successful, then at block 318 the UE uses PLMN A for disaster roaming.

[0044] Those skilled in the art will appreciate that the steps of flowchart 300 need not be performed in a particular order and that the described concepts can still be embodied when performed in another order or when the steps are not utilized. For example, decision block 306 and decision block 308 can be swapped. As an example, UE decision block 316 can be removed and the UE can repeatedly attempt authentication as long as the rejection is a temporary failure. As an example, decision block 306, decision block 308, block 314, or other blocks can be removed entirely. As an example, block 304 can be replaced by another type of PLMN selection.

[0045] like Figure 3 As shown, when the registration request is rejected at the authentication block 312, adding a 5GMM cause value corresponding to the registration failure of disaster roaming on PLMN A due to the disaster situation on PLMN D, and assigning the lowest (or lower) priority to PLMN A at block 320, can provide the UE with a solution for considering transient conditions when selecting a PLMN. This embodiment illustrates that Figure 1 A way to avoid deadlock cycles during UE selection. This selection method can provide higher efficiency, generate less network load, and provide more reliable services.

[0046] Figure 4 4 is a flow chart of a method 400 for a UE to perform PLMN selection for disaster roaming according to one embodiment. In block 402, the method 400 includes determining a disaster situation at a first PLMN, where the UE is a subscriber to the first PLMN. In block 404, the method 400 includes determining the availability of a second PLMN for disaster roaming. In block 406, the method 400 includes selecting a second PLMN and attempting to register for disaster roaming on the second PLMN. In block 408, in response to attempting to register for disaster roaming on the second PLMN, the method 400 includes receiving a registration reject message including a cause value corresponding to a registration failure for disaster roaming on the second PLMN due to the disaster situation on the first PLMN. In block 410, the method 400 includes waiting for a first time period before attempting to register for disaster roaming on the second PLMN for the first PLMN having the disaster situation.

[0047] In certain embodiments of method 400, determining the availability of the second PLMN for disaster roaming includes: detecting a cell of the second PLMN that is located in one of a first list of prohibited PLMNs and a second list of PLMNs with prohibited tracking areas (TAs); and receiving an indication from the cell that the second PLMN provides disaster roaming for the first PLMN.

[0048] In one embodiment, method 400 further includes: processing a registration failure for disaster roaming on a second PLMN including an indication of a temporary failure; incrementing a disaster roaming registration failure counter in response to the temporary failure; waiting for a first time period before attempting to register for disaster roaming on the second PLMN due to the disaster situation on the first PLMN if the disaster roaming registration failure counter has not exceeded a threshold; and attempting to register for disaster roaming on a third PLMN due to the disaster situation on the first PLMN if the disaster roaming registration failure counter has exceeded a threshold.

[0049] In one embodiment, the method 400 further includes: processing an indication that a registration failure for disaster roaming on the second PLMN includes a permanent or persistent failure; in response to the permanent or persistent failure, assigning a lower priority value to the second PLMN; and attempting to select a third PLMN or the second PLMN for disaster roaming based on a higher priority value of the third PLMN (if available) compared to the lower priority value assigned to the second PLMN. In some such embodiments, the lower priority value assigned to the second PLMN is a lowest assignable value.

[0050] In one embodiment of the method 400, the first time period is based on a network-based wait timer. The first time period may be, for example, in the range between 12 hours and 24 hours.

[0051] In one embodiment, method 400 further includes: incrementing a disaster roaming registration failure counter in response to the registration rejection message; if the disaster roaming registration failure counter has exceeded a threshold, attempting disaster roaming registration on a third PLMN due to the disaster condition on the first PLMN; and if the disaster roaming registration failure counter has not exceeded the threshold, waiting for a second time period before attempting disaster roaming registration on the second PLMN due to another disaster condition on the fourth PLMN. In certain such embodiments, method 400 further includes: adding the second PLMN to a list of PLMNs for which registration failed due to disaster roaming; and waiting for the second time period before attempting disaster roaming registration on the fourth PLMN on the list. In other embodiments, the second time period is based on an implementation-specific waiting time. For example, the second time period may be in the range of 3 minutes to 10 minutes.

[0052] In one embodiment, method 400 further includes: incrementing a disaster roaming registration failure counter for each disaster roaming registration failure; calculating a series of time windows for attempting registration, wherein the series of time windows is adjusted by an initial start time; and staggering subsequent registration attempts during the series of time windows subject to an additional offset time that is increased proportionally based on the disaster roaming registration failure counter.

[0053] In one embodiment, method 400 further includes: incrementing a disaster roaming registration failure counter for each disaster roaming registration failure; generating a disaster roaming waiting range using a hash of an international mobile subscriber identity (IMSI) and a random number or a pseudo-random number; and staggering subsequent registration attempts by proportionally increasing the disaster roaming waiting range based on a non-zero value of the disaster roaming registration failure counter.

[0054] In one embodiment, the method 400 further includes: incrementing a disaster roaming registration failure counter for each disaster roaming registration failure; and staggering subsequent registration attempts by proportionally increasing the minimum wait time based on the non-zero value of the disaster roaming registration failure counter.

[0055] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of flowchart 200, flowchart 300, and / or method 400. The apparatus may be, for example, an apparatus of a UE (such as wireless device 702 as a UE, as described herein).

[0056] Embodiments contemplated herein include one or more non-transitory computer-readable media including instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform one or more elements of flowchart 200, flowchart 300, and / or method 400. The non-transitory computer-readable medium may be, for example, a memory of a UE (such as memory 706 of wireless device 702 as a UE, as described herein).

[0057] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry for performing one or more elements of flowchart 200, flowchart 300, and / or method 400. The apparatus may be, for example, an apparatus of a UE (such as wireless device 702 as a UE, as described herein).

[0058] Embodiments contemplated herein 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 one or more elements of flowchart 200, flowchart 300, and / or method 400. The apparatus may be, for example, an apparatus of a UE (such as wireless device 702 as a UE, as described herein).

[0059] Embodiments contemplated herein include signals as described in or associated with one or more elements of flowchart 200 , flowchart 300 , and / or method 400 .

[0060] The embodiments contemplated herein include a computer program or computer program product comprising instructions, wherein execution of the program by a processor causes the processor to perform one or more elements of flowchart 200, flowchart 300, and / or method 400. The processor may be a processor of a UE (such as processor 704 of wireless device 702 as a UE, as described herein). These instructions may, for example, be located in the processor of the UE and / or in a memory of the UE (such as memory 706 of wireless device 702 as a UE, as described herein).

[0061] Figure 5 The present invention is a flow chart of a method 500 for a network device for a disaster situation at a first PLMN. In block 502, in response to a failure to register a UE on a second PLMN for disaster roaming for the first PLMN, the method 500 includes generating a registration reject message including a cause value corresponding to a registration failure for disaster roaming on the second PLMN due to the disaster situation on the first PLMN. In block 504, the method 500 includes sending a registration reject message to the UE including a cause value corresponding to the disaster roaming registration failure.

[0062] In certain embodiments of method 500, the network device includes an access and mobility management function (AMF).

[0063] One embodiment of the method 500 further includes indicating to the UE whether the failure to register the UE on the second PLMN is a temporary failure or a permanent or persistent failure.

[0064] One embodiment of the method 500 further includes configuring the UE with a network-based wait timer comprising a period of time for the UE to wait before reattempting registration for disaster roaming on a second PLMN for a first PLMN having a disaster situation.

[0065] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of flowchart 200, flowchart 300, and / or method 500. The apparatus may be, for example, an apparatus of a base station (such as network device 718 as a base station, as described herein).

[0066] Embodiments contemplated herein include one or more non-transitory computer-readable media including instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform one or more elements of flowchart 200, flowchart 300, and / or method 500. The non-transitory computer-readable medium may be, for example, a memory of a base station (such as memory 722 of network device 718 acting as a base station, as described herein).

[0067] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry for performing one or more elements of flowchart 200, flowchart 300, and / or method 500. The apparatus may be, for example, an apparatus of a base station (such as network device 718 as a base station, as described herein).

[0068] Embodiments contemplated herein 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 one or more elements of flowchart 200, flowchart 300, and / or method 500. The apparatus may be, for example, an apparatus of a base station (such as network device 718 as a base station, as described herein).

[0069] Embodiments contemplated herein include signals as described in or associated with one or more elements of flowchart 200 , flowchart 300 , and / or method 500 .

[0070] The embodiments contemplated herein include a computer program or computer program product comprising instructions, wherein execution of the program by a processing element causes the processing element to perform one or more elements of flowchart 200, flowchart 300, and / or method 500. The processor may be a processor of a base station (such as processor 720 of network device 718 as a base station, as described herein). These instructions may be located, for example, in a processor and / or in a memory of a base station (e.g., memory 722 of network device 718 as a base station, as described herein).

[0071] Figure 6 An exemplary architecture of a wireless communication system 600 according to embodiments disclosed herein is shown. The description provided below is directed to an exemplary wireless communication system 600 operating in conjunction with the LTE system standard and / or the 5G or NR system standard as provided by the 3GPP technical specifications.

[0072] like Figure 6 As shown, wireless communication system 600 includes UE 602 and UE 604 (although any number of UEs may be used). In this example, UE 602 and UE 604 are shown as smartphones (e.g., handheld touchscreen mobile computing devices capable of connecting to one or more cellular networks), but may include any mobile or non-mobile computing device configured for wireless communication.

[0073] UE 602 and UE 604 can be configured to be communicatively coupled to RAN 606. In an embodiment, RAN 606 can be NG-RAN, E-UTRAN, etc. UE 602 and UE 604 utilize connections (or channels) (shown as connection 608 and connection 610, respectively) with RAN 606, where each connection (or channel) includes a physical communication interface. RAN 606 may include one or more base stations (such as base station 612 and base station 614) that implement connection 608 and connection 610.

[0074] In this example, connection 608 and connection 610 are the air interfaces that enable such communicative coupling and may conform to the RAT employed by RAN 606 , such as, for example, LTE and / or NR.

[0075] In some embodiments, UE 602 and UE 604 may also directly exchange communication data via side link interface 616. UE 604 is shown as being configured to access an access point (shown as AP 618) via connection 620. By way of example, connection 620 may include a local wireless connection, such as any connection conforming to the IEEE 802.11 protocol, wherein AP 618 may include In this example, AP 618 may not be connected to another network (eg, the Internet) through CN 624.

[0076] In an embodiment, UE 602 and UE 604 may be configured to communicate with each other or with base station 612 and / or base station 614 using orthogonal frequency division multiplexing (OFDM) communication signals over a multi-carrier communication channel in accordance with various communication techniques, such as, but not limited to, orthogonal frequency division multiple access (OFDMA) communication techniques (e.g., for downlink communication) or single-carrier frequency division multiple access (SC-FDMA) communication techniques (e.g., for uplink and ProSe or sidelink communication), although the scope of the embodiment is not limited in this respect. The OFDM signal may include multiple orthogonal subcarriers.

[0077] In some embodiments, all or part of base station 612 or base station 614 may be implemented as one or more software entities running on a server computer as part of a virtual network. Additionally, or in other embodiments, base station 612 or base station 614 may be configured to communicate with each other via interface 622. In embodiments where wireless communication system 600 is an LTE system (e.g., when CN 624 is an EPC), interface 622 may be an X2 interface. This X2 interface may be defined between two or more base stations (e.g., two or more eNBs, etc.) connected to an EPC and / or between two eNBs connected to an EPC. In embodiments where wireless communication system 600 is an NR system (e.g., when CN 624 is a 5GC), interface 622 may be an Xn interface. This Xn interface may be defined between two or more base stations (e.g., two or more gNBs, etc.) connected to a 5GC, between base station 612 (e.g., a gNB) and an eNB connected to a 5GC, and / or between two eNBs connected to a 5GC (e.g., CN 624).

[0078] RAN 606 is shown communicatively coupled to CN 624. CN 624 may include one or more network elements 626 configured to provide various data and telecommunication services to customers / subscribers (e.g., UE 602 and users of UE 604) connected to CN 624 via RAN 606. Components of CN 624 may be implemented in one physical device or separate physical devices that include components for reading and executing instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium).

[0079] In an embodiment, CN 624 may be an EPC, and RAN 606 may be connected to CN 624 via an S1 interface 628. In an embodiment, S1 interface 628 may be divided into two parts: an S1 user plane (S1-U) interface, which carries traffic data between base station 612 or base station 614 and a serving gateway (S-GW); and an S1-MME interface, which is a signaling interface between base station 612 or base station 614 and a mobility management entity (MME).

[0080] In an embodiment, CN 624 may be a 5GC, and RAN 606 may be connected to CN 624 via an NG interface 628. In an embodiment, NG interface 628 may be divided into two parts: an NG user plane (NG-U) interface, which carries traffic data between base station 612 or base station 614 and a user plane function (UPF); and an S1 control plane (NG-C) interface, which is a signaling interface between base station 612 or base station 614 and an access and mobility management function (AMF).

[0081] Generally speaking, the application server 630 may be an element that provides applications (e.g., packet-switched data services) using Internet Protocol (IP) bearer resources utilizing the CN 624. The application server 630 may also be configured to support one or more communication services (e.g., VoIP sessions, group communication sessions, etc.) for the UE 602 and the UE 604 via the CN 624. The application server 630 may communicate with the CN 624 via an IP communication interface 632.

[0082] Figure 7 A system 700 is shown for performing signaling 734 between a wireless device 702 and a network device 718 according to embodiments disclosed herein. The system 700 can be part of a wireless communication system as described herein. The wireless device 702 can be, for example, a UE of the wireless communication system. The network device 718 can be, for example, a base station (e.g., an eNB or gNB) of the wireless communication system.

[0083] The wireless device 702 may include one or more processors 704. The processor 704 may execute instructions to perform various operations of the wireless device 702 as described herein. The processor 704 may include one or more baseband processors implemented using, for example, a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

[0084] The wireless device 702 may include a memory 706. The memory 706 may be a non-transitory computer-readable storage medium that stores instructions 708 (which may include, for example, instructions executed by the processor 704). The instructions 708 may also be referred to as program code or a computer program. The memory 706 may also store data used by the processor 704 and results computed by the processor.

[0085] The wireless device 702 may include one or more transceivers 710, which may include radio frequency (RF) transmitter and / or receiver circuitry that uses an antenna 712 of the wireless device 702 to facilitate signaling (e.g., signaling 734) to and / or from the wireless device 702 with other devices (e.g., network device 718) in accordance with a corresponding RAT.

[0086] The wireless device 702 may include one or more antennas 712 (e.g., one, two, four, or more). For implementations with multiple antennas 712, the wireless device 702 may leverage the spatial diversity of such multiple antennas 712 to transmit and / or receive multiple different data streams over the same time-frequency resources. This approach may be referred to, for example, as a Multiple-Input Multiple-Output (MIMO) approach (referring to the multiple antennas used on both the transmitting and receiving devices to implement this aspect). MIMO transmissions by the wireless device 702 may be implemented based on precoding (or digital beamforming) applied to the wireless device 702, which multiplexes the data streams across the antennas 712 based on known or assumed channel characteristics, such that each data stream is received at an appropriate signal strength relative to the other streams and at a desired location in the spatial domain (e.g., the location of the receiver associated with that data stream). Certain implementations may utilize Single-User MIMO (SU-MIMO) approaches (where data streams are all intended for a single receiver) and / or Multi-User MIMO (MU-MIMO) approaches (where individual data streams may be intended for individual (different) receivers at different locations in the spatial domain).

[0087] In certain embodiments with multiple antennas, the wireless device 702 may implement analog beamforming techniques whereby the phases of the signals transmitted by the antennas 712 are relatively adjusted so that the (joint) transmissions of the antennas 712 can be directed (this is sometimes referred to as beam steering).

[0088] The wireless device 702 may include one or more interfaces 714. The interfaces 714 may be used to provide input to or output from the wireless device 702. For example, a wireless device 702 that is a UE may include an interface 714, such as a microphone, a speaker, a touch screen, buttons, etc., to allow a user of the UE to provide input to and / or output to the UE. Other interfaces of such a UE may consist of transmitters, receivers, and other circuit systems (e.g., in addition to the transceiver 710 / antenna 712 described above) that allow the UE to communicate with other devices, and may be configured according to known protocols (e.g., etc.) to perform the operation.

[0089] The wireless device 702 may include a PLMN selection module 716. The PLMN selection module 716 may be implemented via hardware, software, or a combination thereof. For example, the PLMN selection module 716 may be implemented as a processor, circuitry, and / or instructions 708 stored in the memory 706 and executed by the processor 704. In some examples, the PLMN selection module 716 may be integrated within the processor 704 and / or the transceiver 710. For example, the PLMN selection module 716 may be implemented via a combination of software components (e.g., executed by a DSP or general-purpose processor) and hardware components (e.g., logic gates and circuitry) within the processor 704 or the transceiver 710.

[0090] The PLMN selection module 716 can be used in various aspects of the present disclosure, such as Figure 2 、 Figure 3 and Figure 4 all aspects.

[0091] The network device 718 may include one or more processors 720. The processor 720 may execute instructions to perform various operations as described herein for the network device 718. The processor 720 may include one or more baseband processors implemented using, for example, a CPU, a DSP, an ASIC, a controller, an FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

[0092] The network device 718 may include a memory 722. The memory 722 may be a non-transitory computer-readable storage medium that stores instructions 724 (which may include, for example, instructions executed by the processor 720). The instructions 724 may also be referred to as program code or a computer program. The memory 722 may also store data used by the processor 720 and results calculated by the processor.

[0093] The network device 718 may include one or more transceivers 726, which may include RF transmitter and / or receiver circuitry that uses an antenna 728 of the network device 718 to facilitate signaling (e.g., signaling 734) to and / or from the network device 718 with other devices (e.g., wireless device 702) in accordance with a corresponding RAT.

[0094] The network device 718 may include one or more antennas 728 (e.g., one, two, four, or more). In embodiments with multiple antennas 728, the network device 718 may perform MIMO, digital beamforming, analog beamforming, beamsteering, etc., as already described.

[0095] The network device 718 may include one or more interfaces 730. The interfaces 730 may be used to provide input to or output from the network device 718. For example, the network device 718 as a base station may include an interface 730 consisting of a transmitter, a receiver, and other circuit systems (e.g., in addition to the transceiver 726 / antenna 728 described above), which enables the base station to communicate with other devices in the core network and / or enables the base station to communicate with external networks, computers, databases, etc., to achieve the purpose of operating, managing, and maintaining the base station or other devices operably connected to the base station.

[0096] The network device 718 may include a registration module 732. The registration module 732 may be implemented via hardware, software, or a combination thereof. For example, the registration module 732 may be implemented as a processor, circuitry, and / or instructions 724 stored in the memory 722 and executed by the processor 720. In some examples, the registration module 732 may be integrated within the processor 720 and / or the transceiver 726. For example, the registration module 732 may be implemented via a combination of software components (e.g., executed by a DSP or general-purpose processor) and hardware components (e.g., logic gates and circuitry) within the processor 720 or the transceiver 726.

[0097] The registration module 732 can be used in various aspects of the present disclosure, such as Figure 2 、 Figure 3 and Figure 4 all aspects.

[0098] Exemplary system architecture

[0099] In certain embodiments, the 5G system architecture supports data connectivity and services, enabling deployment using technologies such as network function virtualization and software-defined networking. The 5G system architecture can utilize service-based interactions between control plane network functions. Separating user plane functions from control plane functions allows independent scalability, evolution, and flexible deployment (e.g., centralized location or distributed (remote) location). Modular function design allows functional reuse and enables flexible and efficient network slicing. A network function and its network function service can interact with another NF and its network function service directly or indirectly via a service communication agent. Another intermediate function can help route control plane messages. The architecture minimizes the dependency between AN and CN. The architecture may include an aggregated core network with a public AN-CN interface that integrates different access types (e.g., 3GPP access and non-3GPP access). The architecture may also support a unified authentication framework, stateless NFs with decoupling of compute and storage resources, capability exposure, concurrent access to local and centralized services (to support low-latency services and access to local data networks, user plane functions may be deployed near the AN), and / or roaming in the visited PLMN with both home-routed traffic as well as local breakout traffic.

[0100] The 5G architecture can be defined as service-based, and the interactions between network functions can include service-based representations, where a network function within the control plane (e.g., AMF) enables other authorized network functions to access its services. The service-based representation can also include point-to-point reference points. The reference point representation can also be used to show the interactions between NF services in network functions described by a point-to-point reference point (e.g., N11) between any two network functions (e.g., AMF and SMF).

[0101] Figure 8 FIG800 shows a service-based architecture 800 in 5GS according to one embodiment. As described in 3GPP TS 23.501, the service-based architecture 800 includes NFs such as NSSF 808, NEF 810, NRF 814, PCF 812, UDM 826, AUSF 818, AMF 820, and SMF 822 to communicate with UE 816, (R)AN 806, UPF 802, and DN 804. NFs and NF services can communicate directly (referred to as direct communication) or indirectly via SCP 824 (referred to as indirect communication). Figure 8 Also shown are the corresponding service-based interfaces including Nutm, Naf, Nudm, Npcf, Nsmf, Nnrf, Namf, Nnef, Nnssf and Nausf and reference points N1, N2, N3, N4 and N6. Figure 8 Some exemplary functions provided by the NF are shown.

[0102] The NSSF 808 supports functions such as: selecting a set of network slice instances to serve the UE; determining the allowed NSSAIs and, if required, the mapping to the subscribed S-NSSAIs; determining the configured NSSAIs and, if required, the mapping to the subscribed S-NSSAIs; and / or determining the set of AMFs to be used to serve the UE, or a list of candidate AMFs, possibly by querying the NRF based on the configuration.

[0103] NEF 810 supports the exposure of capabilities and events. NF capabilities and events can be securely exposed by NEF 810 (e.g., for third parties, application functions and / or edge computing). NEF 810 can store / retrieve information as structured data using a standardized interface to UDR (Nudr). NEF 810 can also securely provide information from external applications to the 3GPP network, and can provide application functions to securely provide information (e.g., expected UE behavior, 5GLAN group information, and service-specific information) to the 3GPP network, where NEF 810 can authenticate and authorize and help limit application functions. NEF 810 can provide internal-external information conversion by converting between information exchanged with AF 828 and information exchanged with internal network functions. For example, NEF 810 converts between AF service identifiers and internal 5G core information (such as DNN and S-NSSAI). NEF 810 can handle the masking of network and user sensitive information of external AFs based on network policies. The NEF 810 can receive information from other network functions (based on the exposed capabilities of the other network functions) and store the received information as structured data using a standardized interface to the UDR. The stored information can be accessed by the NEF 810 and re-exposed to other network functions and application functions, and used for other purposes such as analysis. For external exposure of services related to a specific UE, the NEF 810 can reside in the HPLMN. Depending on the operator agreement, the NEF 810 in the HPLMN may have an interface with the NF in the VPLMN. When the UE is capable of handover between the EPC and the 5GC, the SCEF+NEF can be used for service exposure.

[0104] The NRF 814 supports service discovery functionality by receiving NF discovery requests from NF instances or SCPs and providing information about the discovered NF instances to the NF instances or SCPs. The NRF 814 may also support P-CSCF discovery (a special case of SMF discovery of AFs), maintain NF profiles of available NF instances and their supported services, and / or notify subscribed NF service consumers or SCPs of newly registered / updated / deregistered NF instances along with their NF services. In the context of network slicing, based on network specific implementation, multiple NRFs may be deployed at different levels, such as PLMN level (NRF configured with information about the entire PLMN), shared slice level (NRF configured with information belonging to a network slice set), and / or slice-specific level (NRF configured with information belonging to the S-NSSAI). In the context of roaming, multiple NRFs may be deployed in different networks, where the NRF in the visited PLMN (called vNRF) is configured with information about the visited PLMN, and where the NRF in the home PLMN (called hNRF) is configured with information about the home PLMN, referenced by the vNRF via the N27 interface.

[0105] The PCF 812 supports a unified policy framework to govern network behavior. The PCF 812 provides policy rules for control plane functions to enforce them. The PCF 812 accesses subscription information related to policy decisions in the Unified Data Repository (UDR). The PCF 812 can access the UDR located in the same PLMN as the PCF.

[0106] The UDM 826 supports the generation of 3GPP AKA authentication credentials, user identification processing (e.g., storage and management of the SUPI for each subscriber in the 5G system), unhiding of the privacy-preserving subscription identifier (SUCI), access authorization based on subscription data (e.g., roaming restrictions), UE registration with the serving NF (e.g., storing the service AMF for the UE and storing the service SMF for the UE's PDU session), service / session continuity (e.g., by maintaining SMF / DNN allocation for ongoing sessions), MT-SMS delivery, lawful intercept functionality (particularly in outbound roaming scenarios where the UDM is the sole point of contact for the LI), subscription management, SMS management, 5G LAN group management processing, and / or external parameter configuration (expected UE behavior parameters or network configuration parameters). To provide such functionality, the UDM 826 uses subscription data (including authentication data) that may be stored in the UDR. In this case, the UDM implements the application logic and may not require internal user data storage, and several different UDMs may serve the same user in different transactions. The UDM 826 may be located in the HPLMN of the subscriber it serves and may access information from UDRs located in the same PLMN.

[0107] The AUSF 818 supports authentication for 3GPP access and untrusted non-3GPP access. The AUSF 818 may also provide support for network slice-specific authentication and authorization.

[0108] The AMF 820 supports termination of the RAN CP interface (N2), termination of NAS (N1) for NAS encryption and integrity protection, registration management, connection management, reachability management, mobility management, lawful interception (for AMF events and interfaces to the LI system), transport of SMS messages between the UE and SMF, transparent proxy for routing SM messages, access authentication, access authorization, transport of SMS messages between the UE and SMSF, SEAF, location service management for regulated services, transport of location service messages between the UE and LMF and between the RAN and LMF, EPS bearer ID allocation for interworking with EPS, UE mobility event notification, control plane CIoT 5GS optimization, user plane CIoT 5GS optimization, configuration of external parameters (expected UE behavior parameters or network configuration parameters), and / or network slice-specific authentication and authorization. Some or all of the AMF functions may be supported in a single instance of the AMF 820. Regardless of the number of network functions, in some embodiments, only one NAS interface instance per access network between the UE and the CN terminates at one of the network functions that implements at least NAS security and mobility management. The AMF 820 may also include policy-related functions.

[0109] In addition to the above functions, the AMF 820 may include the following functions to support non-3GPP access networks: support the N2 interface with the N3IWF / TNGF, on which some information (e.g., 3GPP cell identification) and procedures (e.g., related to handover) defined on 3GPP access may not be applicable, and non-3GPP access specific information that is not applicable to 3GPP access may be applied; support NAS signaling with UE through the N3IWF / TNGF, where some procedures supported by NAS signaling through 3GPP access may not be applicable to untrusted non-3GPP (e.g., paging) access; support authentication of UEs connected through the N3IWF / TNGF; management of mobility, authentication, and separate security context states for UEs connected via non-3GPP access or via both 3GPP access and non-3GPP access; support coordinated RM management contexts valid on 3GPP access and non-3GPP access; and / or support dedicated CM management contexts for UEs connected via non-3GPP access. It may not be necessary to support all of the above functions in the instance of network slicing.

[0110] The SMF 822 supports session management (e.g., session establishment, modification, and release, including tunnel maintenance between the UPF and AN nodes), UE IP address allocation and management (including optional authorization) (where the UE IP address may be received from the UPF or from an external data network), DHCPv4 (server and client) and DHCPv6 (server and client) functions, functions for responding to Address Resolution Protocol requests and / or IPv6 neighbor solicitation requests based on local cache information of Ethernet PDUs (e.g., the SMF responds to ARP and / or IPv6 neighbor solicitation requests by providing the MAC address corresponding to the IP address sent in the request), selection and control of user plane functions (including controlling the UPF to proxy ARP or IPv6 neighbor discovery or forwarding all ARP / IPv6 neighbor solicitation traffic to the SMF for Ethernet PDU sessions), traffic steering configuration at the UPF to route traffic to the appropriate destination, 5G VN group management (e.g., maintaining the topology of the involved PSA UPFs, in which the PSA Establish and issue N19 tunnels between UPFs, configure traffic forwarding at UPF to apply local switching and / or N6-based forwarding or N19-based forwarding), terminate interfaces towards policy control function, lawful interception (for SM events and interfaces to LI system), charge for data collection and support billing interfaces, control and coordination of billing data collection at UPF, terminate SM part of NAS messages, downlink data notification, initiator of AN-specific SM information sent to AN via AMF over N2, determination of SSC mode for session, control plane CIoT 5GS optimization, header compression, act as I-SMF in deployments where I-SMF can be inserted / removed / relocated, configure external parameters (expected UE behavior parameters or network configuration parameters), P-CSCF discovery for IMS services, roaming functions (e.g., handling local implementation to apply QoS SLA (VPLMN), charging data collection and charging interface (VPLMN) and / or lawful interception (in VPLMN for SM events and interface to LI system), interaction with external DN to transmit signaling for PDU session authentication / authorization for external DN and / or instructing UPF and NG-RAN to perform redundant transmission on N3 / N9 interface. Some or all of the SMF functions may be supported in a single instance of SMF. However, in some embodiments, not all functions need to be supported in an instance of a network slice. In addition to the functions, the SMF 822 may include policy-related functions.

[0111] The SCP 824 includes one or more of the following functions: indirect communication; delegated discovery; message forwarding and routing to the destination NF / NF service; communication security (e.g., authorization of NF service consumers to access NF service manufacturer APIs), load balancing, monitoring, overload control, etc.; and / or optionally interacting with the UDR to resolve the UDM group ID / UDR group ID / AUSF group ID / PCF group ID / CHF group ID / HSS group ID based on the UE identity (e.g., SUPI or IMPI / IMPU). Some or all of the SCP functions may be supported in a single instance of the SCP. In certain embodiments, the SCP 824 may be deployed in a distributed manner and / or more than one SCP may be present in the communication path between NF services. The SCP may be deployed at the PLMN level, the shared slice level, and the slice-specific level. Operator deployment may be left to ensure that the SCP can communicate with the relevant NRFs.

[0112] UE 816 may include a device with radio communication capabilities. For example, UE 816 may include a smartphone (e.g., a handheld touchscreen mobile computing device that can connect to one or more cellular networks). UE 816 may also include any mobile or non-mobile computing device, such as a personal data assistant (PDA), a pager, a laptop, a desktop computer, a wireless handheld device, or any computing device that includes a wireless communication interface. UE is also referred to as a client, mobile phone, mobile device, mobile terminal, user terminal, mobile unit, mobile station, mobile user, subscriber, user, remote station, access agent, user agent, receiver, radio device, reconfigurable radio device, or reconfigurable mobile device. UE 816 may include an IoT UE, which may include a network access layer designed for low-power IoT applications that utilize short-term UE connections. The IoT UE may exchange data with an MTC server or device via a PLMN, other UEs using ProSe or D2D communications, a sensor network, or an IoT network using technologies (e.g., M2M, MTC, or mMTC technologies). M2M or MTC data exchanges may be machine-initiated data exchanges. The IoT network describes interconnected IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure). The IoT UEs may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate connectivity to the IoT network.

[0113] The UE 816 may be configured to connect or communicatively couple with the (R)AN 806 via a radio interface 830, which may be a physical communication interface or layer configured to operate with a cellular communication protocol such as a GSM protocol, a CDMA network protocol, a push-to-talk (PTT) protocol, a PTT over cellular (POC) protocol, a UMTS protocol, a 3GPP LTE protocol, a 5G protocol, a NR protocol, etc. For example, the UE 816 and the (R)AN 806 may use a Uu interface (e.g., an LTE-Uu interface) to exchange control plane data via a protocol stack including a PHY layer, a MAC layer, an RLC layer, a PDCP layer, and an RRC layer. DL transmissions may be from the (R)AN 806 to the UE 816, and UL transmissions may be from the UE 816 to the (R)AN 806. The UE 816 may also use a side link to directly communicate with another UE (not shown) for D2D, P2P, and / or ProSe communication. For example, the ProSe interface may include 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).

[0114] The (R)AN 806 may include one or more access nodes, which may be referred to as base stations (BSs), Node Bs, evolved Node Bs (eNBs), next generation Node Bs (gNBs), RAN nodes, controllers, transmission reception points (TRPs), etc., and may include ground stations (e.g., terrestrial access points) or satellite stations, which provide coverage within a geographic area (e.g., a cell). The (R)AN 806 may include one or more RAN nodes for providing macro cells, pico cells, femto cells, or other types of cells. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access to a UE with a service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access to a UE with a service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access to UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in a home, etc.).

[0115] Although not shown, multiple RAN nodes (such as (R)AN 806) may be used, with an Xn interface defined between two or more nodes. 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 functions. The Xn-C may provide management and error handling functions for managing the functions of the Xn-C interface; mobility support for UE 816 in connected mode (e.g., CM-CONNECTED) includes functions for managing UE mobility in connected mode between one or more (R)AN nodes. This mobility support may include context transfer from an old (source) serving (R)AN node to a new (target) serving (R)AN node; and control of a user plane tunnel between the old (source) serving (R)AN node and the new (target) serving (R)AN node.

[0116] The UPF 802 can serve as an anchor point for intra-RAT and inter-RAT mobility, an external PDU session point interconnected with the DN 804, and a branch point to support multi-homed PDU sessions. The UPF 802 can also perform packet routing and forwarding, packet inspection, enforce the user plane portion of policy rules, lawful interception of packets (UP collection); traffic usage reporting, perform QoS processing on the user plane (e.g., packet filtering, gating, UL / DL rate enforcement), perform uplink traffic validation (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. The UPF 802 may include an uplink classifier to support routing of traffic flows to the data network. The DN 804 may represent various network operator services, Internet access, or third-party services. The DN 804 may include, for example, an application server.

[0117] For one or more embodiments, at least one of the components shown in one or more of the foregoing figures may be configured to perform one or more operations, techniques, processes, and / or methods as described herein. For example, the baseband processor described herein in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the examples described herein. For another example, the circuitry associated with the UE, base station, network element, etc. described above in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the examples shown herein.

[0118] Unless expressly stated otherwise, any of the above embodiments may be combined with any other embodiment (or combination of embodiments). The foregoing description of one or more specific implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of the embodiments to the precise forms disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the various embodiments.

[0119] Embodiments and implementations of the systems and methods described herein may include various operations that may be embodied in machine-executable instructions to be executed by a computer system. A computer system may include one or more general-purpose or special-purpose computers (or other electronic devices). A computer system may include hardware components that include specific logic components for performing the operations, or may include a combination of hardware, software, and / or firmware.

[0120] It should be understood that the systems described herein include descriptions of specific embodiments. These embodiments can be combined into a single system, partially integrated into other systems, separated into multiple systems, or otherwise divided or combined. In addition, it is contemplated that parameters, attributes, aspects, etc. of one embodiment can be used in another embodiment. For clarity, these parameters, attributes, aspects, etc. are described only in one or more embodiments, and it should be understood that unless otherwise stated herein, these parameters, attributes, aspects, etc. can be combined with or substituted for parameters, attributes, aspects, etc. of another embodiment.

[0121] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly stated to users.

[0122] Although the foregoing has been described in considerable detail for purposes of clarity, it will be apparent that certain changes and modifications may be made without departing from the principles of the invention. It should be noted that there are many alternative ways of implementing both the processes and the apparatus described herein. The embodiments of the present invention are therefore to be considered illustrative and not restrictive, and the description is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

[0123] For one or more embodiments, at least one of the components shown in one or more of the foregoing figures may be configured to perform one or more operations, techniques, processes, and / or methods as described herein. For example, the baseband processor described herein in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the examples described herein. For another example, the circuitry associated with the UE, base station, network element, etc. described above in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the examples shown herein.

[0124] Unless expressly stated otherwise, any of the above embodiments may be combined with any other embodiment (or combination of embodiments). The foregoing description of one or more specific implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of the embodiments to the precise forms disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the various embodiments.

[0125] Embodiments and implementations of the systems and methods described herein may include various operations that may be embodied in machine-executable instructions to be executed by a computer system. A computer system may include one or more general-purpose or special-purpose computers (or other electronic devices). A computer system may include hardware components that include specific logic components for performing the operations, or may include a combination of hardware, software, and / or firmware.

[0126] It should be understood that the systems described herein include descriptions of specific embodiments. These embodiments can be combined into a single system, partially integrated into other systems, separated into multiple systems, or otherwise divided or combined. In addition, it is contemplated that parameters, attributes, aspects, etc. of one embodiment can be used in another embodiment. For clarity, these parameters, attributes, aspects, etc. are described only in one or more embodiments, and it should be understood that unless otherwise stated herein, these parameters, attributes, aspects, etc. can be combined with or substituted for parameters, attributes, aspects, etc. of another embodiment.

[0127] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly stated to users.

[0128] Although the foregoing has been described in considerable detail for purposes of clarity, it will be apparent that certain changes and modifications may be made without departing from the principles of the invention. It should be noted that there are many alternative ways of implementing both the processes and the apparatus described herein. The embodiments of the present invention are therefore to be considered illustrative and not restrictive, and the description is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

Claims

1. A method for a user equipment (UE) to perform public land mobile network (PLMN) selection for disaster roaming, the method comprising: determining a disaster situation at a first PLMN, wherein the UE is a subscriber of the first PLMN; determining availability of a second PLMN for the disaster roaming; selecting the second PLMN and attempting to register for the disaster roaming on the second PLMN; receiving, in response to attempting the registration for the disaster roaming on the second PLMN, a registration reject message including a cause value corresponding to a registration failure for the disaster roaming on the second PLMN due to the disaster situation on the first PLMN; waiting for a first time period before retrying to register the disaster roaming on the second PLMN for the first PLMN having the disaster situation; In response to the registration rejection message, incrementing a disaster roaming registration failure counter; If the disaster roaming registration failure counter has exceeded a threshold, attempting to register the disaster roaming on a third PLMN due to the disaster situation on the first PLMN; as well as If the disaster roaming registration failure counter has not exceeded the threshold, waiting for a second time period before attempting to register the disaster roaming on the second PLMN due to another disaster situation on a fourth PLMN.

2. The method of claim 1 , wherein determining the availability of the second PLMN for the disaster roaming comprises: detecting a cell of the second PLMN, the cell being in one of a first list of forbidden PLMNs and a second list of PLMNs having a forbidden tracking area TA; as well as An indication that the second PLMN provides the disaster roaming for the first PLMN is received from the cell.

3. The method according to claim 1, further comprising: Processing the registration failure of the disaster roaming on the second PLMN including an indication of a temporary failure; In response to the temporary failure, incrementing a disaster roaming registration failure counter; If the disaster roaming registration failure counter has not exceeded a threshold, waiting for the first time period before attempting to register the disaster roaming on the second PLMN due to the disaster situation on the first PLMN; as well as If the disaster roaming registration failure counter has exceeded the threshold, attempting to register the disaster roaming on a third PLMN due to the disaster situation on the first PLMN.

4. The method according to claim 1, further comprising: handling the registration failure for the disaster roaming on the second PLMN including an indication of a permanent or persistent failure; In response to the permanent or persistent failure, assigning a lower priority value to the second PLMN; as well as Based on a higher priority value of a third PLMN compared to the lower priority value assigned to the second PLMN, the third PLMN attempts to select the third PLMN or the second PLMN for the disaster roaming, if available.

5. The method of claim 4, wherein the lower priority value assigned to the second PLMN is a lowest assignable value. The method of claim 1 , wherein the first time period is based on a network-based wait timer. The method of claim 6 , wherein the first period of time is in the range between 12 hours and 24 hours.

8. The method according to claim 1, further comprising: adding the second PLMN to a list of PLMNs for which registration has failed due to the disaster roaming; as well as Waiting for the second time period before attempting to register the disaster roaming on a PLMN in the list for the fourth PLMN.

9. The method of claim 1, wherein the second time period is based on an implementation-specific wait time.

10. The method of claim 9, wherein the second time period is in the range between 3 minutes and 10 minutes.

11. The method according to claim 1 or claim 3, further comprising: Incrementing the disaster roaming registration failure counter for each disaster roaming registration failure; calculating a series of time windows for attempting the registration, wherein the series of time windows is modulated by an initial start time; as well as Subsequent registration attempts are staggered during the series of time windows subject to an additional offset time that is increased proportionally according to the disaster roaming registration failure counter.

12. The method according to claim 1 or claim 3, further comprising: Incrementing the disaster roaming registration failure counter for each disaster roaming registration failure; Generating a disaster roaming standby range using an International Mobile Subscriber Identity (IMSI) and a hash of a random number or a pseudo-random number; and Subsequent registration attempts are staggered by proportionally increasing the disaster roaming wait range based on a non-zero value of the disaster roaming registration failure counter.

13. The method according to claim 1 or claim 3, further comprising: Incrementing the disaster roaming registration failure counter for each disaster roaming registration failure; as well as Subsequent registration attempts are staggered by proportionally increasing a minimum wait time based on a non-zero value of the disaster roaming registration failure counter.

14. A computer program product comprising instructions which, when executed by a processor, implement the steps of the method according to any one of claims 1 to 13.

15. An apparatus for disaster roaming, the apparatus comprising means for implementing the steps of the method according to any one of claims 1 to 13.

Images