Technique for disaster roaming registration procedure using forbidden tracking area identity list

Abstract

In one aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus can be a user equipment. The user equipment determines that a disaster condition applies to the user equipment. In response to determining that the disaster condition applies, the user equipment selects a public land mobile network for disaster roaming service. The selected public land mobile network is associated with at least one tracking area identity that is included in a list of forbidden tracking area identities stored in the user equipment. The user equipment attempts to register with the selected public land mobile network using the at least one tracking area identity.

Description

[0001] Cross-referencing

[0002] This application claims priority to Indian Patent Application Serial No. 202321074740, filed on November 2, 2023, entitled “Method for Utilizing FTAI List for Disaster Roaming Registration Process”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to communication systems, and more specifically, to techniques for enabling user equipment to access prohibited tracking areas included in a list of prohibited tracking area identifiers during disaster roaming registration. Background Technology

[0004] The statements in this section provide only background information in connection with this disclosure and may not constitute prior art.

[0005] Wireless communication systems are widely deployed to provide a variety of telecommunications services, such as telephone, video, data, messaging, and broadcasting. Typical wireless communication systems employ various multi-user access technologies, supporting communication with multiple users by sharing available system resources. Examples of such multi-user access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0006] These multi-user access technologies have been adopted in various telecommunications standards to provide a common protocol enabling different wireless devices to communicate at the city, national, regional, and even global levels. One example of a telecommunications standard is 5G New Radio (NR). 5G NR is part of the ongoing evolution of mobile broadband driven by the Third Generation Partnership Project (3GPP) to meet new requirements related to latency, reliability, security, scalability (e.g., the Internet of Things, IoT), and other needs. Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Further improvements to 5G NR technology are still needed. These improvements may also apply to other multi-user access technologies and the telecommunications standards that adopt them. Summary of the Invention

[0007] The following is a simplified summary of one or more aspects to provide a basic understanding of them. This summary is not a comprehensive overview of all conceived aspects, nor is it intended to identify key or essential elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present certain concepts of one or more aspects in a simplified form as a prelude to a more detailed description thereafter.

[0008] In one aspect of this disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a user equipment (UE). The UE determines that disaster conditions apply to it. In response to determining that the disaster conditions apply, the UE selects a Public Land Mobile Network (PLMN) for disaster roaming services. The selected PLMN is associated with at least one tracking area identity (TAI) included in a list of prohibited tracking area identities stored in the UE. The UE attempts to register with the selected PLMN using the at least one tracking area identity.

[0009] To achieve the foregoing and related objectives, one or more aspects include the features fully described below and specifically pointed out in the claims. The following description and accompanying drawings illustrate certain exemplary features of one or more aspects in detail. However, these features only illustrate a portion of how the principles of the various aspects can be applied, and this description is intended to include all such aspects and their equivalents. Attached Figure Description

[0010] Figure 1This is a schematic diagram illustrating an example wireless communication system and access network.

[0011] Figure 2 This is a schematic diagram illustrating communication between a base station and user equipment in an access network.

[0012] Figure 3 Example of a distributed access network's logical architecture.

[0013] Figure 4 Example of a distributed access network physical architecture.

[0014] Figure 5 This is a schematic diagram illustrating a downlink-centric time slot.

[0015] Figure 6 This is a schematic diagram illustrating an example of a time slot centered on the uplink.

[0016] Figure 7 A schematic diagram illustrating communication between user equipment, conventional public terrestrial mobile networks, and public terrestrial mobile networks for disaster purposes.

[0017] Figure 8 Flowchart of a method for utilizing prohibited tracking area identifiers during disaster roaming registration. Detailed Implementation

[0018] The detailed description below, taken in conjunction with the accompanying drawings, is intended to describe various configurations and is not intended to represent the only configuration in which the concepts described herein can be practiced. The detailed description includes specific details to provide a thorough understanding of the various concepts. However, those skilled in the art will understand that these concepts can be practiced without these specific details. In some cases, to avoid obscuring these concepts, known structures and components are shown in block diagram form.

[0019] Several aspects of telecommunications systems will now be introduced in conjunction with various apparatuses and methods. These apparatuses and methods will be described in detail below and illustrated with accompanying drawings as various modules, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented by electronic hardware, computer software, or any combination thereof. Whether an element is implemented in hardware or software depends on the specific application and design constraints imposed on the overall system.

[0020] For example, a single element, any portion of an element, or any combination of elements can be implemented as a “processing system” comprising one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on a chip (SoCs), baseband processors, field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other hardware suitable for performing the various functions described in this disclosure. One or more processors in a processing system can execute software. Software should be understood broadly as instructions, instruction sets, code, code segments, program code, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., regardless of whether it is referred to as software, firmware, middleware, microcode, hardware description languages, or other names.

[0021] Therefore, in one or more example aspects, the functionality can be implemented by hardware, software, or any combination thereof. If implemented by software, these functions can be stored or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media. Storage media can be any existing medium accessible to a computer. For example, but not limited to, such computer-readable media can include random-access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), optical disc storage, magnetic disk storage, other magnetic storage devices, combinations of computer-readable media of the above types, or any medium that can be used to store computer-executable code in the form of instructions or data structures and is accessible to a computer.

[0022] Figure 1The illustration shows an example of a wireless communication system and access network 100. The wireless communication system (also known as a wireless wide area network (WWAN)) includes base station 102, user equipment 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). Base station 102 may include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). Macro cells include base stations. Small cells include femtocells, picocells, and microcells.

[0023] Base station 102 configured as 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with EPC 160 via backhaul link 132 (e.g., SI interface). Base station 102 configured as 5G NR (collectively referred to as Next Generation RAN (NG-RAN)) can interface with core network 190 via backhaul link 184. In addition to other functions, base station 102 may perform one or more of the following functions: user data transmission, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, non-access stratum (NAS) message distribution, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), user and device tracking, RAN Information Management (RIM), paging, location, and warning message delivery. Base station 102 may communicate with each other directly or indirectly (e.g., via EPC 160 or core network 190) via backhaul link 134 (e.g., X2 interface). Backhaul link 134 may be wired or wireless.

[0024] Base station 102 can wirelessly communicate with user equipment 104. Each base station 102 can provide communication coverage for a corresponding geographic coverage area 110. Geographic coverage areas 110 may overlap. For example, small cell 102' may have a coverage area 110' that overlaps with the coverage areas 110 of one or more macro base stations 102. A network containing small cells and macro cells can be called a heterogeneous network. Heterogeneous networks may also include Home Evolved Node B (HeNB), which can provide services to a restricted group called a closed subscriber group (CSG). The communication link 120 between base station 102 and user equipment 104 may include uplink (UL, also known as reverse link) transmission from user equipment 104 to base station 102 and / or downlink (DL, also known as forward link) transmission from base station 102 to user equipment 104. Communication link 120 may employ multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may be implemented using one or more carriers. Base station 102 / user equipment 104 may use a spectrum with a bandwidth of up to 7 MHz (e.g., 5, 10, 15, 20, 100, 400 MHz, etc.) per carrier, allocating a total of Yx MHz (x component carriers) for transmission in carrier aggregation in each direction. Carriers may be adjacent or non-adjacent. Carrier allocation in the DL and UL directions may be asymmetrical (e.g., more or fewer carriers allocated to DL than to UL). Component carriers may include primary component carriers and one or more auxiliary component carriers. The primary component carrier may be referred to as the primary cell (PCell), and the auxiliary component carriers may be referred to as secondary cells (SCells).

[0025] Some user equipment 104 can communicate with each other via device-to-device (D2D) communication link 158. D2D communication link 158 can use DL / UL wireless wide area network spectrum. D2D communication link 158 can use one or more sidelink channels, such as physical sidelink broadcast channel (PSBCH), physical sidelink discovery channel (PSDCH), physical sidelink shared channel (PSSCH), and physical sidelink control channel (PSCCH). D2D communication can be implemented through various wireless D2D communication systems, such as FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0026] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154 in the 5 GHz unlicensed spectrum. During unlicensed spectrum communication, the STA 152 / AP 150 may perform a clear channel assessment (CCA) before communication to determine channel availability.

[0027] Small cell 102' can operate in licensed and / or unlicensed spectrum. When operating in unlicensed spectrum, small cell 102' can employ NR and use the same 5 GHz unlicensed spectrum as Wi-Fi access point 150. Employing NR and operating in unlicensed spectrum can improve the coverage and / or increase the capacity of the access network.

[0028] Base station 102, whether a small cell 102' or a large cell (e.g., a macro base station), may include evolved Node B (eNB), gNodeB (gNB), or other types of base stations. Some base stations, such as gNB 180, can communicate with user equipment (UE) 104 in conventional sub-6 GHz bands, millimeter wave (mmW) frequencies, and / or near-millimeter wave frequencies. When gNB 180 operates at millimeter wave or near-millimeter wave frequencies, gNB 180 may be referred to as a millimeter wave base station. Extremely high frequency (EHF) is a radio frequency component of the electromagnetic spectrum. EHF ranges from 30 GHz to 300 GHz, with wavelengths between 1 mm and 10 mm. Radio waves in this band may be referred to as millimeter waves. Near-millimeter waves can extend down to 3 GHz with wavelengths of 100 mm. Ultra-high frequency (SHF) bands range from 3 GHz to 30 GHz and are also known as centimeter waves. Communication using millimeter-wave / near-millimeter-wave radio frequency bands (e.g., 3 GHz - 300 GHz) suffers from extremely high path loss and short range. Millimeter-wave base station 180 can use beamforming 182 to communicate with user equipment 104 to compensate for the extremely high path loss and short range.

[0029] Base station 180 can transmit beamforming signals to user equipment 104 in one or more transmit directions 108a. User equipment 104 can receive beamforming signals from base station 180 in one or more receive directions 108b. User equipment 104 can also transmit beamforming signals to base station 180 in one or more transmit directions. Base station 180 can receive beamforming signals from user equipment 104 in one or more receive directions. Base station 180 / user equipment 104 can perform beam training to determine the optimal receive and transmit directions for each. The transmit and receive directions of base station 180 can be the same or different. The transmit and receive directions of user equipment 104 can be the same or different.

[0030] The evolved packet core (EPC) 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. MME 162 can communicate with the Home Subscriber Server (HSS) 174. MME 162 is the control node that handles signaling between User Equipment 104 and EPC 160. Typically, MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through the Serving Gateway 166, which is itself connected to the PDN Gateway 172. The PDN Gateway 172 provides user equipment IP address allocation and other functions. The PDN Gateway 172 and BM-SC 170 are connected to the IP service 176. IP service 176 may include the Internet, intranet, IP Multimedia Subsystem (IMS), Packet Switched Streaming Service (PS Streaming Service), and / or other IP services. BM-SC 170 can provide MBMS user service configuration and delivery functions. BM-SC 170 can serve as an entry point for content provider MBMS transmission, can be used to authorize and initiate MBMS bearer services within a Public Land Mobile Network (PLMN), and can be used to schedule MBMS transmissions. MBMS gateway 168 can be used to distribute MBMS traffic to base station 102 that belongs to a Multicast Broadcast Single Frequency Network (MBSFN) area and broadcast specific services, and can be responsible for session management (start / stop) and collecting billing information related to enhanced MBMS (eMBMS).

[0031] The core network 190 may include an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Location Management Function (LMF) 198, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may communicate with the Unified Data Management (UDM) 196. The AMF 192 is the control node that handles signaling between the User Equipment 104 and the core network 190. Typically, the SMF 194 provides QoS flow and session management. All user Internet Protocol (IP) packets are transmitted through the UPF 195. The UPF 195 provides user equipment IP address allocation and other functions. The UPF 195 connects to an IP service 197. The IP service 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), packet-switched streaming services, and / or other IP services.

[0032] A base station may also be referred to as a gNB, Node B, evolved Node B (eNB), access point, base transceiver, wireless base station, wireless transceiver, transceiver function, basic service set (BSS), extended service set (ESS), transmit reception point (TRP), or other suitable terms. Base station 102 provides user equipment 104 with access to EPC 160 or core network 190. Examples of user equipment 104 include cellular phones, smartphones, session initiation protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radios, GPS devices, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablets, smart devices, wearable devices, vehicles, electricity meters, gas pumps, large or small kitchen appliances, medical devices, implants, sensors / actuators, displays, or any other similarly functional devices. Some user equipment 104 may be referred to as Internet of Things (IoT) devices (e.g., parking meters, gas pumps, toasters, vehicles, heart monitors, etc.). User equipment 104 may also be referred to as a station, mobile station, user station, mobile unit, user unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile user station, access terminal, mobile terminal, wireless terminal, remote terminal, handheld device, user agent, mobile client, client, or other suitable terms.

[0033] Although this disclosure may relate to 5G New Radio (NR), it also applies to other similar fields, such as LTE, LTE-Advanced (LTE-A), Code Division Multiple Access (CDMA), Global System for Mobile communications (GSM), or other wireless / radio frequency access technologies.

[0034] Figure 2This is a block diagram illustrating communication between base station 210 and user equipment 250 in the access network. In the downlink (DL), IP packets from EPC 160 can be provided to controller / processor 275. Controller / processor 275 implements Layer 3 and Layer 2 functions. Layer 3 includes the radio resource control (RRC) layer, and Layer 2 includes the packet data convergence protocol (PDCP) layer, radio link control (RLC) layer, and medium access control (MAC) layer. The controller / processor 275 provides RRC layer functions related to system information broadcasting (e.g., Master Information Block (MIB), System Information Blocks (SIBs)), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-Radio Access Technology (RAT) mobility, and measurement configuration for user equipment measurement reports; PDCP layer functions related to header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions related to uplink layer packet data units (PDUs) transmission, error correction via Automatic Repeat Request (ARQ), concatenation, segmentation, and reassembly of RLC service data units (SDUs), resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and mapping between logical channels and transport channels, multiplexing of MAC SDUs on transport blocks (TBs), and MAC... SDUs handle MAC layer functions related to TBs, including demultiplexing, scheduling information reporting, error correction via Hybrid Automatic Repeat Request (HARQ), priority handling, and logical channel priority.

[0035] Transmit (TX) processor 216 and receive (RX) processor 270 implement Layer 1 functions related to various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection of the transport channel, forward error correction (FEC) encoding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and multiple-input multiple-output (MIMO) antenna processing. TX processor 216 processes the mapped signal constellation according to various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), and M-quadrature amplitude modulation (M-QAM)). The encoded and modulated symbols can then be split into parallel streams. Each stream can then be mapped to an OFDM subcarrier, multiplexed in the time and / or frequency domains with a reference signal (e.g., a pilot), and then combined using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a stream of time-domain OFDM symbols. The OFDM streams are spatially precoded to generate multiple spatial streams. Channel estimates from channel estimator 274 can be used to determine coding and modulation schemes, as well as spatial processing. The channel estimates can be derived from the reference signal and / or channel condition feedback transmitted by user equipment 250. Each spatial stream can then be provided to different antennas 220 via a separate transmitter 218TX. Each transmitter 218TX can modulate an RF carrier with the corresponding spatial stream for transmission.

[0036] At user equipment 250, each receiver 254RX receives a signal via its corresponding antenna 252. Each receiver 254RX recovers the information modulated onto the radio frequency carrier and provides the information to the receive (RX) processor 256. The TX processor 268 and RX processor 256 implement Layer 1 functions related to various signal processing functions. The RX processor 256 can perform spatial processing on the information to recover any spatial stream facing user equipment 250. If multiple spatial streams are facing user equipment 250, they can be merged into a single OFDM symbol stream by the RX processor 256. The RX processor 256 then uses a Fast Fourier Transform (FFT) to transform the OFDM symbol stream from the time domain to the frequency domain. The frequency domain signal consists of a separate OFDM symbol stream for each OFDM signal subcarrier. The symbols on each subcarrier, along with the reference signal, are recovered and demodulated by determining the most probable signal constellation point transmitted by base station 210. These soft decisions can be based on a channel estimate calculated by channel estimator 258. The soft decision is then decoded and deinterleaved to recover the data and control signals initially transmitted by base station 210 on the physical channel. The data and control signals are then provided to controller / processor 259, which implements Layer 3 and Layer 2 functions.

[0037] Controller / processor 259 may be associated with memory 260, which stores program code and data. Memory 260 may be referred to as computer-readable medium. In the uplink, controller / processor 259 provides demultiplexing, packet reassembly, decryption, header decompression, and control signal processing between transport and logical channels to recover IP packets from Evolved Packet Core (EPC) 160. Controller / processor 259 is also responsible for error detection using ACK and / or NACK protocols to support Hybrid Automatic Repeat reQuest (HARQ) operation.

[0038] Similar to the downlink transmission functions of base station 210, controller / processor 259 provides RRC layer functions related to system information (e.g., Master Information Block (MIB), System Information Blocks (SIBs)) acquisition, Radio Resource Control (RRC) connectivity, and measurement reporting; Packet Data Convergence Protocol (PDCP) layer functions related to header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); Radio Link Control (RLC) layer functions related to upper-layer Protocol Data Unit (PDU) transmission, error correction via Automatic Repeat reQuest (ARQ), connectivity, segmentation and reassembly of RLC Service Data Units (SDUs), resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and mapping between logical channels and transport channels, multiplexing of MAC SDUs to Transport Blocks (TBs), and MAC... SDU functions from TB demultiplexing, scheduling information reporting, error correction via HARQ, priority handling, and logical channel priority-related Medium Access Control (MAC) layer functions.

[0039] The channel estimate derived by the channel estimator 258 from the reference signal or feedback sent by the base station 210 can be used by the TX processor 268 to select a suitable coding and modulation scheme and facilitate spatial processing. The spatial stream generated by the TX processor 268 can be provided to different antennas 252 via individual transmitters 254TX. Each transmitter 254TX can modulate an RF carrier with the corresponding spatial stream for transmission. Uplink transmission is processed at the base station 210 in a manner similar to that described in relation to the receiving function of the user equipment 250. Each receiver 218RX receives the signal through its corresponding antenna 220. Each receiver 218RX recovers the information modulated onto the RF carrier and provides the information to the RX processor 270.

[0040] Controller / processor 275 may be associated with memory 276, which stores program code and data. Memory 276 may be referred to as computer-readable medium. In the uplink, controller / processor 275 provides demultiplexing, packet reassembly, decryption, header decompression, and control signal processing between transport and logical channels to recover IP packets from user equipment 250. IP packets from controller / processor 275 may be provided to EPC 160. Controller / processor 275 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operation.

[0041] New Radio (NR) can refer to a radio configured to operate under a new air interface (e.g., a non-Orthogonal Frequency Divisional Multiple Access (OFDMA) air interface) or a fixed transport layer (e.g., non-Internet Protocol (IP)). NR can utilize Orthogonal Frequency Division Multiplexing (OFDM) with a cyclic prefix (CP) on both the uplink and downlink, and may include support for half-duplex operation using Time Division Duplexing (TDD). NR can include Enhanced Mobile Broadband (eMBB) services targeting wide bandwidth (e.g., above 80 MHz), millimeter wave (mmW) services targeting high carrier frequencies (e.g., 60 GHz), massive machine-type communication (mMTC) services targeting non-backward-compatible MTC technologies, and / or mission-critical services targeting ultra-reliable low-latency communications (URLLC) services.

[0042] It can support a single component carrier bandwidth of 100 MHz. In one example, an NR resource block (RB) can span 12 subcarriers with a subcarrier bandwidth of 60 kHz for 0.25 ms, or a bandwidth of 30 kHz for 0.5 ms (similarly, a 15 kHz subcarrier spacing (SCS) provides a 50 MHz bandwidth over a 1 ms duration). Each radio frame can consist of 10 subframes (10, 20, 40, or 80 NR slots) with a length of 10 ms. Each slot can indicate the link direction of data transmission (i.e., downlink or uplink), and the link direction of each slot can be dynamically switched. Each slot can include downlink / uplink data and downlink / uplink control data. The uplink and downlink slots of NR can be combined as follows. Figure 5 and Figure 6 More detailed description.

[0043] A Radio Access Network (RAN) can include Central Units (CUs) and Distributed Units (DUs). NR Base Stations (BSs) (e.g., gNBs, 5G NodeBs, Node Bs, Transmission Reception Points (TRPs), Access Points (APs)) can correspond to one or more base stations. NR cells can be configured as Access Cells (ACells) or Data Cells (DCells). For example, the RAN (e.g., Central Units or Distributed Units) can configure these cells. DCells can be used for carrier aggregation or dual connectivity and may not be used for initial access, cell selection / reselection, or handover. In some cases, DCells may not transmit a Synchronization Signal (SS), and in others they may transmit an SS. NR base stations can transmit downlink signals to User Equipment (UEs) indicating the cell type. Based on the cell type indication, UEs can communicate with NR base stations. For example, UEs can determine which NR base stations to consider based on the indicated cell type for cell selection, access, handover, and / or measurement.

[0044] Figure 3An example logical architecture of a distributed radio access network (RAN) 300 is illustrated according to relevant aspects of this disclosure. A 5G access node 306 may include an access node controller (ANC) 302. This access node controller may be the central unit (CU) of the distributed radio access network. Backhaul interfaces to a next-generation core network (NG-CN) 304 may terminate at this access node controller. Backhaul interfaces to neighboring next-generation access nodes (NG-ANs) 310 may terminate at this access node controller. The access node controller may include one or more transport access points (TRPs) 308 (also referred to as base stations (BSs), new radio base stations (NR BSs), Node Bs, 5G NBs, access points (APs), or other terms). As mentioned above, transport access points can be used interchangeably with "cells".

[0045] The transport access point 308 may be a distributed unit (DU). The transport access point may connect to one access node controller (ANC 302) or multiple access node controllers (not shown). For example, for radio access network sharing, radio as a service (RaaS), and service-specific access node controller deployments, the transport access point may connect to multiple access node controllers. The transport access point may include one or more antenna ports. The transport access point may be configured to provide services to user equipment (UE) individually (e.g., dynamically selected) or jointly (e.g., jointly transmitted).

[0046] The local architecture of the distributed radio access network 300 can be used to illustrate the fronthaul definition. This architecture can be defined as a fronthaul solution supporting different deployment types. For example, the architecture can be based on transport network capabilities (e.g., bandwidth, latency, and / or jitter). The architecture can share features and / or components with Long Term Evolution (LTE). Depending on the relevant aspects, the Next Generation Access Node (NG-AN) 310 can support dual connectivity with New Radio (NR). This NG-AN can share a common fronthaul for both LTE and NR.

[0047] This architecture enables collaboration between and within the transport access points 308. For example, collaboration can be pre-defined within the transport access points and / or implemented across transport access points via the access node controller 302. Depending on the relevant parties, interfaces between transport access points may be unnecessary or nonexistent.

[0048] According to relevant sources, the architecture of the Distributed Radio Access Network 300 can have a dynamic configuration with logical function segmentation. Packet Data Convergence Protocol (PDCP), Radio Link Control (RLC), and Media Access Control (MAC) protocols can be adaptively placed in the access node controller or the transmission access point.

[0049] Figure 4 An example physical architecture of a distributed radio access network 400 is illustrated, according to relevant aspects of this disclosure. A centralized core network unit (C-CU) 402 can host core network functions. This centralized core network unit can be deployed centrally. The functions of the centralized core network unit can be offloaded (e.g., to advanced wireless services (AWS)) to handle peak capacity. A centralized radio access network unit (C-RU) 404 can host one or more access node controller functions. Optionally, the centralized radio access network unit can host core network functions locally. The centralized radio access network unit can be deployed in a distributed manner. The centralized radio access network unit can be located closer to the network edge. A distributed unit (DU) 406 can host one or more transport access points. The distributed unit can be located at the network edge with radio frequency (RF) capabilities.

[0050] Figure 5 Figure 500 illustrates an example of a downlink (DL)-centric timeslot. The downlink-centric timeslot may include a control section 502. The control section 502 may exist in the initial or beginning portion of the downlink-centric timeslot. The control section 502 may include various scheduling and / or control information corresponding to different portions of the downlink-centric timeslot. In some configurations, the control section 502 may be a physical downlink control channel (PDCCH), such as... Figure 5 As shown. The downlink-centric time slot may also include a downlink data portion 504. The downlink data portion 504 may sometimes be referred to as the payload of the downlink-centric time slot. The downlink data portion 504 may include communication resources used for communicating downlink data from a scheduling entity (e.g., a user equipment or base station) to a subordinate entity (e.g., a user equipment). In some configurations, the downlink data portion 504 may be a physical downlink shared channel (PDSCH).

[0051] The downlink-centric time slot may also include a general uplink portion 506. The general uplink portion 506 may sometimes be referred to as an uplink burst, a general uplink burst, and / or other applicable terms. The general uplink portion 506 may include feedback information corresponding to other portions of the downlink-centric time slot. For example, the general uplink portion 506 may include feedback information corresponding to the control portion 502. Non-limiting examples of feedback information may include acknowledgment (ACK) signals, denial (NACK) signals, hybrid automatic repeat request (HARQ) indicators, and / or other applicable types of information. The general uplink portion 506 may include additional or alternative information, such as information related to random access channel (RACH) procedures, scheduling requests (SRs), and other applicable types of information.

[0052] like Figure 5 As shown, the end of the downlink data portion 504 can be time-separated from the start of the general uplink portion 506. This time separation may sometimes be referred to as a gap, protection period, protection interval, and / or other applicable terms. This separation provides time for the switching from downlink communication (e.g., a receiving operation of a subordinate entity (e.g., a user equipment)) to uplink communication (e.g., a transmitting operation of a subordinate entity (e.g., a user equipment)). Those skilled in the art will understand that the above is merely one example of a downlink-centric time slot, and alternative structures with similar characteristics may exist without departing from the relevant aspects described herein.

[0053] Figure 6 Figure 600 illustrates an example of an uplink (UL)-centric timeslot. An uplink-centric timeslot may include a control section 602. The control section 602 may be present at the beginning or start portion of the uplink-centric timeslot. Figure 6 The control section 602 in the above reference can be used as a reference. Figure 5 The control portion 502 is described similarly. The uplink-centric time slot may also include an uplink data portion 604. The uplink data portion 604 may sometimes be referred to as the payload of the uplink-centric time slot. The uplink portion may refer to the communication resources used for communicating uplink data from a subordinate entity (e.g., a user equipment) to a scheduling entity (e.g., a user equipment or a base station). In some configurations, the control portion 602 may be the Physical Downlink Control Channel (PDCCH).

[0054] like Figure 6As shown, the end of control section 602 can be time-separated from the start of uplink data section 604. This time separation may sometimes be referred to as a gap, protection period, protection interval, and / or other applicable terms. This separation provides time for the switching from downlink communication (e.g., a receive operation by a scheduling entity) to uplink communication (e.g., a transmit operation by a scheduling entity). Uplink-centric time slots may also include a general uplink section 606. Figure 6 The general uplink section 606 in the reference above can be used as a reference. Figure 5 The general uplink section 506 described herein is similar. The general uplink section 606 may also include or replace information related to channel quality indicators (CQI), sounding reference signals (SRSs), and other applicable types of information. Those skilled in the art will understand that the above is merely an example of an uplink-centric time slot, and alternative structures with similar characteristics may exist without departing from the relevant aspects described herein.

[0055] In some cases, two or more dependent entities (e.g., user equipment) can communicate using sidechain signals. Practical applications of such sidechain communication can include public safety, proximity services, user equipment-to-network relay, vehicle-to-vehicle (V2V) communication, Internet of Everything (IoE) communication, Internet of Things (IoT) communication, mission-critical mesh networks, and other applicable applications. Generally, a sidechain signal can refer to a signal used to communicate from one dependent entity (e.g., user equipment 1) to another dependent entity (e.g., user equipment 2) without relaying the communication through a scheduling entity (e.g., user equipment or base station), although the scheduling entity may be used for scheduling and / or control purposes. In some examples, sidechain signals can communicate using licensed spectrum (unlike wireless LANs that typically use unlicensed spectrum).

[0056] Figure 7Figure 700 illustrates communication between User Equipment 704, a conventional public land mobile network 710, and a disaster-use public land mobile network 720. User Equipment 704 connects to base station 702 under normal operation and is initially registered to the conventional public land mobile network 710, which can be the User Equipment's Home Public Land Mobile Network (HPLMN) or Visited Public Land Mobile Network (VPLMN). The conventional public land mobile network 710 provides standard cellular service to User Equipment 704 under normal conditions via base station 702. The disaster-use public land mobile network 720 operates base station 712, which is adjacent to base station 702. The disaster-use public land mobile network 720 may be a prohibited public land mobile network for User Equipment 704 under normal conditions.

[0057] Disaster roaming is a feature specified by the 3rd Generation Partnership Project (3GPP) that allows users to access other mobile networks (e.g., a Public Land Mobile Network (PLMN) 720 for disaster purposes) during disasters or emergencies, even if their home network (e.g., a regular public land mobile network 710) is unavailable. This feature enables users to access voice and data services on other networks when their home network is interrupted due to a disaster or emergency. Information about disaster roaming can be broadcast by the regular public land mobile network 710 in a System Information Block (SIB).

[0058] In the event of a disaster, such as a tsunami or earthquake, User Equipment (UE) 704 may lose coverage from the regular public terrestrial mobile network 710. To maintain communication services during such events, the Minimization of Service Interruption (MINT) function comes into play. Both UE 704 and the network must support MINT to enable this function.

[0059] MINT is a feature designed to provide uninterrupted service to user equipment (UE) in disaster scenarios. When disaster conditions affect the Registered Public Land Mobile Network (RPLMN) to which a UE is registered, MINT enables the UE to obtain service from other RPLMNs that provide disaster roaming services. This allows users to maintain communication even when their home network is compromised.

[0060] MINT facilitates disaster roaming and provides continuous service availability in emergency situations by enabling user equipment to select and register with public terrestrial mobile networks for disaster purposes. MINT implements wait timers, such as disaster roaming wait ranges and disaster return wait ranges, to prevent network congestion during disasters. These timers introduce random delays before user equipment attempts to register with a public terrestrial mobile network for disaster purposes or return to its home network, thereby mitigating potential overload on the relevant networks.

[0061] In one example, UE 704 initially connects to the conventional public land mobile network 710 via base station 702. The conventional public land mobile network 710, as the UE's home public land mobile network (HPLMN), provides standard cellular service under normal operating conditions. UE 704 maintains a Tracking Area Identity (TAI) list, which includes tracking areas (TAs) that are not allowed to register due to previous network registration rejections. The TAI list includes a "5GS TAI list for roaming" and a "5GS TAI list for area service provision." These rejections may be accompanied by specific reason values, such as reason #12 "Tracking area not allowed," reason #13 "Roaming is not allowed in this tracking area," or reason #15 "No suitable cell in the tracking area."

[0062] In the event of a disaster, such as an earthquake or tsunami, the infrastructure of the conventional public land mobile network 710 may be damaged or completely unavailable. In this situation, UE 704 loses connection to the conventional public land mobile network 710 and cannot access standard cellular services. To mitigate service interruption during a disaster, the Service Interruption Minimization (MINT) function enables UE 704 to obtain service from a public land mobile network that provides disaster roaming services, such as the disaster-purpose public land mobile network 720. The disaster-purpose public land mobile network 720 operates base station 712, which may be located near UE 704 and can provide connectivity during a disaster.

[0063] In the first configuration, under automatic public land mobile network selection mode, UE 704 does not consider tracking areas in the prohibited tracking area identifier list when searching for networks that can provide service. This behavior may lead to service interruption for users in disaster scenarios. This is because the UE (such as UE 704) may have received a registration rejection message from a network (such as public land mobile network 720 for disaster purposes) with reason values ​​of #12 "Tracking area not allowed", #13 "Roaming is not allowed in this tracking area", or #15 "No suitable cell in the tracking area", and added the corresponding tracking area to the prohibited tracking area identifier list. These reason values ​​indicate that the UE is not allowed to operate in the specified tracking area due to subscription or roaming restrictions. For example, if UE 704 attempts to register with public land mobile network 720 for disaster purposes under normal conditions via base station 712 and is rejected, the corresponding tracking area identifier will be added to the prohibited tracking area identifier list.

[0064] During a disaster, the regular public land mobile network 710 is unavailable, and the disaster-specific public land mobile network 720 may be the only network providing service. However, if UE 704 has a tracking area served by base station 712 in its list of prohibited tracking area identifiers, UE 704 will not attempt to register with the disaster-specific public land mobile network 720, even if base station 712 can provide disaster roaming service. This situation is exacerbated when, after the disaster condition ends, the network (potentially the disaster-specific public land mobile network 720) sends a reason #13 "Roaming is not allowed in this tracking area" message to UE 704, prompting UE 704 to add the current tracking area identifier to its list of prohibited tracking area identifiers. This means that even if a tracking area served by base station 712 previously provided disaster roaming service, UE 704 cannot select that tracking area in subsequent disaster scenarios because it has been added to the list of prohibited tracking area identifiers.

[0065] To address the issues raised in the first configuration, a second configuration is proposed. In this configuration, UE 704 is able to access tracking areas in its List of Prohibited Tracking Area Identifiers (TAIs) in disaster situations. This scheme allows UE 704 to obtain disaster roaming services from public terrestrial mobile networks (such as public terrestrial mobile network 720 for disaster purposes), even if these tracking areas are marked as prohibited due to previous registration denials.

[0066] When UE 704 determines that a disaster condition exists—whether through direct network indication or otherwise—it can override standard restrictions imposed by the list of prohibited tracking areas. Specifically, during the automatic or manual public terrestrial mobile network selection process for disaster roaming services, UE 704 is configured to ignore entries in both the "List of 5GS Prohibited Tracking Areas for Roaming" and the "List of 5GS Prohibited Tracking Areas for Area Service Provision." This allows UE 704 to consider and attempt to register tracking areas that are excluded under normal circumstances.

[0067] For example, when a disaster occurs and the regular public land mobile network 710 is unavailable, UE 704 can detect information broadcast by the disaster-purpose public land mobile network 720, instructing it to provide disaster roaming services. In this scenario, even though the tracking area of ​​the disaster-purpose public land mobile network 720 is included in the list of prohibited tracking areas due to past rejections, UE 704 can still attempt to register with it. This ensures that UE 704 can maintain connectivity and obtain necessary services under disaster conditions.

[0068] Although UE 704 can access tracking areas in the prohibited tracking area identifier list during a disaster, UE 704 will not remove these tracking areas from the list by accessing them. This means that once the disaster condition ends, UE 704 will resume normal behavior and avoid these tracking areas during public terrestrial mobile network selection.

[0069] In addition, when attempting to register for disaster roaming services, UE 704 may also access public land mobile networks included in its "Prohibited Public Land Mobile Networks" or "Prohibited Public Land Mobile Networks for GPRS Services" lists. The standard for such access is specified in Clause 4.4.3.1.1 of the 3GPP Technical Specification (3GPP TS 23.122). For example, the UE may select the following networks: a registered public land mobile network or an equivalent public land mobile network (if available); public land mobile networks in the "User-Controlled Public Land Mobile Network Selector and Access Technology" list; and / or public land mobile networks in the "Operator-Controlled Public Land Mobile Network Selector and Access Technology" list. The UE considers signal quality when selecting a public land mobile network. If signal level enhancement network selection is applicable, the UE may select a public land mobile network with a received signal quality equal to or higher than the "Operator-Controlled Per-Access Technology Signal Threshold" configured in the USIM. Similar to the handling of the prohibited tracking area identifier list, UE 704 will not remove any entries from the prohibited public land mobile network list due to access during disaster conditions.

[0070] Therefore, UE 704 can obtain disaster roaming services from available public terrestrial mobile networks, even if the corresponding tracking area or public terrestrial mobile network is on a prohibited list. This enhances the UE's ability to maintain communication services when regular public terrestrial mobile networks are unavailable.

[0071] Figure 8 This is a flowchart 800 of a method for utilizing a prohibited tracking area identifier during disaster roaming registration. This method can be performed by a user equipment (such as UE 704). In operation 802, the UE determines that a disaster condition applies to it. In some configurations, to determine that a disaster condition applies, the UE receives a disaster condition indication broadcast by the network or detects a loss of connection with the registered public terrestrial mobile network.

[0072] In operation 804, in response to determining that disaster conditions apply, the UE selects a public terrestrial mobile network (PTN) for disaster roaming services. The selected PTN is associated with at least one tracking area identifier included in a list of prohibited tracking area identifiers stored in the UE. In some configurations, the UE selects this PTN for disaster roaming services in either automatic or manual PTN selection mode. In some configurations, the prohibited tracking area identifier list includes at least a "5GS prohibited tracking area list for roaming" or a "5GS prohibited tracking area list for area service provision." To select a PTN, the UE ignores the contents of the prohibited tracking area identifier list during the PTN selection process for disaster roaming services. In some configurations, the UE is configured to not consider entries in the prohibited tracking area identifier list when selecting a PTN for disaster roaming services during disaster conditions.

[0073] In operation 806, the user equipment attempts to register with the selected public terrestrial mobile network using the at least one tracking area identifier. In some configurations, the at least one tracking area identifier is added to the prohibited tracking area identifier list because a previous registration was rejected and the reason value indicates that the tracking area identifier is prohibited. In some configurations, the reason value includes at least one of the following: reason #12 "Tracking area not allowed", reason #13 "Roaming is not allowed in this tracking area", or reason #15 "No suitable cell in the tracking area".

[0074] In operation 808, after registering with the selected public land mobile network using the at least one tracking area identifier, the user equipment retains the at least one tracking area identifier in the list of prohibited tracking area identifiers. In operation 810, after determining that the disaster conditions are no longer applicable, the user equipment avoids selecting public land mobile networks associated with tracking area identifiers included in the list of prohibited tracking area identifiers.

[0075] In some configurations, when a user equipment (UE) selects a public land mobile network (PRM) for disaster roaming services, it accesses PRMs included in a list of prohibited PRMs stored in the UE. In other configurations, when the UE accesses this PRM during disaster roaming services, it avoids removing any PRMs from the prohibited PRM list.

[0076] It should be understood that the specific order or hierarchy of blocks in the disclosed process / flowchart is merely exemplary. Based on design preferences, it should be understood that the specific order or hierarchy of blocks in the process / flowchart can be rearranged. Furthermore, certain blocks can be combined or omitted. The appended method claims present the elements of each block in an exemplary order and are not limited to the specific order or hierarchy shown.

[0077] The foregoing description is intended to enable those skilled in the art to implement the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to limit the aspects shown herein, but rather to provide a full scope consistent with the language of the claims, wherein a singular reference to an element does not mean “only one” unless explicitly stated otherwise, but rather “one or more.” The term “exemplary” is used herein to mean “as an example, instance, or illustration.” Any aspect described as “exemplary” is not necessarily to be construed as preferred or superior to other aspects. Unless otherwise explicitly stated, the term “some” means one or more. Combinations such as “at least one A, B, or C,” “one or more A, B, or C,” “at least one A, B, and C,” “one or more A, B, and C,” and “A, B, C, or any combination thereof” include any combination of A, B, and / or C, and may include multiple A, multiple B, or multiple C. Specifically, combinations such as “at least one A, B, or C,” “one or more A, B, or C,” “at least one A, B, and C,” “one or more A, B, and C,” and “A, B, C, or any combination thereof” can be only A, only B, only C, A and B, A and C, B and C, or A, B, and C, wherein any such combination may include one or more members of A, B, or C. All structural and functional equivalents of the aspects described in this disclosure, whether known or subsequently known to those skilled in the art, are expressly incorporated herein by reference and are intended to be covered by the claims. Furthermore, the disclosure herein is not intended for public disclosure, whether or not such disclosure is expressly recited in the claims. Terms such as “module,” “mechanism,” “element,” and “device” may not be substitutes for the word “means.” Therefore, no claim element should be construed as means plus function unless the element expressly uses the phrase “means for…”.

Claims

1. A wireless communication method performed by a user equipment, comprising: Determine if the disaster conditions apply to the user's equipment; In response to determining that the disaster conditions apply: Select a public land mobile network for disaster roaming services, wherein the public land mobile network is associated with at least one tracking area identifier included in a list of prohibited tracking area identifiers stored in the user equipment; as well as Try registering with the selected public land mobile network using at least one tracking area identifier.

2. The method of claim 1, wherein the user equipment selects the public land mobile network for disaster roaming service in either automatic public land mobile network selection mode or manual public land mobile network selection mode.

3. The method of claim 1, wherein the list of prohibited tracking areas includes at least one of the following: List of 5GS no-tracking zones for roaming; or List of 5GS-prohibited tracking areas used for regional services.

4. The method of claim 1, further comprising: After registering with the selected public land mobile network using at least one tracking area identifier, the at least one tracking area identifier is retained in the list of prohibited tracking area identifiers.

5. The method of claim 1, wherein selecting the public land mobile network comprises: The contents of the list of prohibited tracking areas are ignored during the selection of public terrestrial mobile networks for disaster roaming services.

6. The method of claim 1, further comprising: When selecting a public land mobile network for disaster roaming service, access the public land mobile networks included in the list of prohibited public land mobile networks stored in the user equipment.

7. The method of claim 6, wherein when the user equipment accesses the public land mobile network during disaster roaming service, it avoids removing any public land mobile network from the list of prohibited public land mobile networks.

8. The method of claim 1, wherein the at least one tracking area identifier is added to the list of prohibited tracking area identifiers because previous registration was rejected and the reason value indicates that the tracking area identifier is prohibited.

9. The method of claim 8, wherein the cause value includes at least one of the following: Reason #12 "Tracking area not allowed"; Reason #13 "Roaming is not allowed in this tracking area"; or Reason #15 "No suitable cell in the tracking area".

10. The method of claim 1, wherein determining that the disaster condition applies to the user equipment comprises: Receive disaster condition instructions broadcast via the network; or The system detected a loss of connection to the registered public terrestrial mobile network.

11. The method of claim 1, wherein the user equipment is configured to disregard entries in the list of prohibited tracking areas when selecting the public terrestrial mobile network for disaster roaming service during the disaster condition.

12. The method of claim 1, further comprising: After it is determined that the disaster conditions no longer apply: Avoid selecting public land mobile networks that are associated with tracking area identifiers included in the list of prohibited tracking area identifiers.

13. An apparatus for wireless communication, the apparatus being a user equipment, comprising: Memory; as well as At least one processor, coupled to the memory and configured as follows: Determine if the disaster conditions apply to the user's equipment; In response to determining that the disaster conditions apply: Select a public land mobile network for disaster roaming services, wherein the public land mobile network is associated with at least one tracking area identifier included in a list of prohibited tracking area identifiers stored in the user equipment; as well as Try registering with the selected public land mobile network using at least one tracking area identifier.

14. The apparatus of claim 13, wherein the at least one processor is configured to select the public land mobile network for disaster roaming service in either an automatic public land mobile network selection mode or a manual public land mobile network selection mode.

15. The apparatus of claim 13, wherein the list of prohibited tracking areas includes at least one of the following: List of 5GS no-tracking zones for roaming; or List of 5GS-prohibited tracking areas used for regional services.

16. The apparatus of claim 13, wherein the at least one processor is further configured to retain the at least one tracking area identifier in the list of prohibited tracking area identifiers after registering with the selected public land mobile network using the at least one tracking area identifier.

17. The apparatus of claim 13, wherein, for selecting the public terrestrial mobile network, the at least one processor is configured to ignore the contents of the list of prohibited tracking areas during the public terrestrial mobile network selection process for disaster roaming services.

18. The apparatus of claim 13, wherein the at least one processor is configured to access public land mobile networks included in a list of prohibited public land mobile networks stored in the user equipment when selecting the public land mobile network for disaster roaming service.

19. The apparatus of claim 18, wherein the at least one processor is configured to avoid removing any public land mobile network from the list of prohibited public land mobile networks due to access to the public land mobile network during disaster roaming service.

20. A computer-readable medium storing instructions that, when executed by a processor of a user equipment, cause the user equipment to: Determine if the disaster conditions apply to the user's equipment; In response to determining that the disaster conditions apply: Select a public terrestrial mobile network for disaster roaming services, wherein the public terrestrial mobile network is associated with at least one tracking area identifier included in a list of prohibited tracking area identifiers stored in the user equipment; and Try registering with the selected public land mobile network using at least one tracking area identifier.

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