WO2021227002A1

WO2021227002A1 - Self-adaptation for multi-subscriber user equipment (ue) in wireless networks

Info

Publication number: WO2021227002A1
Application number: PCT/CN2020/090499
Authority: WO
Inventors: Jian Li; Hao Zhang; Fojian ZHANG; Chaofeng HUI; Yuankun ZHU; Yi Liu; Meng Liu; Yun Peng; Jingnan QU
Original assignee: Qualcomm Incorporated
Priority date: 2020-05-15
Filing date: 2020-05-15
Publication date: 2021-11-18

Abstract

This disclosure provides methods, devices, and systems for self-adaptation in wireless networks. Some implementations more specifically relate to dynamically adapting a multi-subscriber user equipment (UE) to wireless networks implemented in accordance with standalone (SA) and non-standalone (NSA) 5G network architectures. The UE may initially register first and second subscriber identities with a 5G SA network. In some implementations, the UE may detect an abnormality with the 5G SA network if, after a number of attempts in a relatively short duration, the UE fails to establish or maintain a PDU session with the network on behalf of the first subscriber identity. In some implementations, the UE may selectively deregister the second subscriber identity from the 5G SA network and register the second subscriber identity with a 5G NSA network based on the detected abnormality.

Description

SELF-ADAPTATION FOR MULTI-SUBSCRIBER USER EQUIPMENT (UE) IN WIRELESS NETWORKS

TECHNICAL FIELD

This disclosure relates generally to wireless communication and, more specifically, to self-adaptation techniques for multi-subscriber user equipment (UE) in wireless networks.

DESCRIPTION OF THE RELATED TECHNOLOGY

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-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.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR) , which is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT) ) , and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB) , massive machine type communications (mMTC) , and ultra-reliable low latency communications (URLLC) . Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in 5G NR technology.

5G networks can be implemented in accordance with standalone (SA) or non-standalone (NSA) architectures. The 5G SA architecture includes a 5G core (5GC) and one or more base stations configured for 5G NR (such as gNBs) to provide 5G services to a user equipment (UE) . The 5GC provides native support for many of the improvements associated with 5G NR technology such as, for example, URLLC, network function virtualization (NFV) , network slicing, control and user plane separation (CUPS) , and multi-gigabit connectivity, among other examples. On the other hand, the 5G NSA architecture includes an evolved packet core (EPC) and a combination of base stations configured for 4G LTE and base stations configured for 5G NR (such as eNBs and gNBs, respectively) to provide 5G services to a UE. By integrating base stations configured for 5G NR into existing 4G LTE infrastructure, wireless networks implementing the 5G NSA architecture may support some of the improvements associated with 5G NR technology such as, for example, eMBB.

The 5G SA architecture offers many advantages over the 5G NSA architecture. However, the 5G NSA architecture provides a relatively fast and low-cost means for deploying 5G NR services by leveraging existing 4G LTE infrastructure. Moreover, because 4G LTE infrastructure is more mature, wireless networks based on the 5G NSA architecture may be more robust or reliable than newer wireless networks based on the 5G SA architecture. Thus, it may be desirable for a 5G-capable UE to dynamically adapt its wireless radios, under various circumstances, to receive 5G services from wireless networks implementing 5G SA or 5G NSA network architectures.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a diagram of an example wireless communications system and an access network.

Figures 2A, 2B, 2C, and 2D show examples of a first 5G/NR frame, downlink (DL) channels within a 5G/NR slot, a second 5G/NR frame, and uplink (UL) channels within a 5G/NR slot, respectively.

Figure 3 shows a block diagram of an example base station and user equipment (UE) in an access network.

Figure 4 shows an example wireless communication system according to some implementations.

Figure 5 shows a sequence diagram depicting an example message exchange between a multi-subscriber UE and base stations associated with multiple wireless networks according to some implementations.

Figure 6 shows a sequence diagram depicting an example message exchange between a multi-subscriber UE and base stations associated with multiple wireless networks according to some implementations.

Figure 7 shows a sequence diagram depicting an example message exchange between a multi-subscriber UE and base stations associated with multiple wireless networks according to some implementations.

Figure 8A shows a flowchart illustrating an example process for wireless communication that supports self-adaptation for multi-subscriber UEs in wireless networks according to some implementations.

Figure 8B shows a flowchart illustrating an example process for wireless communication that supports self-adaptation for multi-subscriber UEs in wireless networks according to some implementations.

Figure 9 shows a flowchart illustrating an example process for wireless communication that supports self-adaptation for multi-subscriber UEs in wireless networks according to some implementations.

Figure 10 shows a block diagram of an example UE according to some implementations.

DETAILED DESCRIPTION

The following description is directed to some particular implementations for the purposes of describing innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. The described implementations can be implemented in any device, system or network that is capable of transmitting and receiving radio frequency (RF) signals according to one or more of the Long Term Evolution (LTE) , 3G, 4G or 5G (New Radio (NR) ) standards promulgated by the 3rd Generation Partnership Project (3GPP) , the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, the IEEE 802.15 standards, or the

standards as defined by the Bluetooth Special Interest Group (SIG) , among others. The described implementations can be implemented in any device, system or network that is capable of transmitting and receiving RF signals according to one or more of the following technologies or techniques: code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal FDMA (OFDMA) , single-carrier FDMA (SC-FDMA) , single-user (SU) multiple-input multiple-output (MIMO) and multi-user (MU) MIMO. The described implementations also can be implemented using other wireless communication protocols or RF signals suitable for use in one or more of a wireless wide area network (WWAN) , a wireless personal area network (WPAN) , a wireless local area network (WLAN) , or an internet of things (IOT) network.

Various implementations relate generally to self-adaptation in wireless networks. Some implementations more specifically relate to dynamically adapting a multi-subscriber user equipment (UE) to wireless networks implemented in accordance with standalone (SA) and non-standalone (NSA) 5G network architectures. The UE may initially register first and second subscriber identities with a 5G SA network. As used herein, the term “5G SA network” may refer to any wireless network implemented in accordance with the 5G SA architecture or any 5G network including a 5G core (5GC) . In some implementations, the UE may detect an abnormality with the 5G SA network if, after a number of attempts in a relatively short duration, the UE fails to establish or maintain a PDU session between the network and a wireless radio associated with the first subscriber identity. In some implementations, the UE may selectively deregister the second subscriber identity from the 5G SA network and register the second subscriber identity with a 5G NSA network based on the detected abnormality. As used herein, the term “5G NSA network” may refer to any wireless network implemented in accordance with the 5G NSA architecture or any 5G network including an evolved packet core (EPC) .

Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. Aspects of the present disclosure enable 5G-capable UEs to adapt to abnormalities in 5G networks and acquire 5G services faster or sooner than would otherwise be possible according to existing 5G standards. Because many 5G SA networks are still under development, certain abnormalities in 5G SA networks may persist for a relatively long duration. On the other hand, because 4G LTE infrastructure is relatively mature, 5G NSA networks may be more robust or reliable than some 5G SA networks. By detecting abnormalities that prevent a UE from maintaining a PDU session with a 5G SA network, the UE is able to dynamically migrate from the 5G SA network to a 5G NSA network that is more likely to provide 5G services to the UE. By changing the registration of one subscriber identity from a 5G SA network to a 5G NSA network based on abnormalities detected in the 5G SA network on behalf of another subscriber identity, aspects of the present disclosure may further reduce the latency or signaling overhead in acquiring 5G services by at least one of the subscriber identities associated with a multi-subscriber UE.

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes 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 (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Accordingly, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer- readable media can comprise a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

Figure 1 shows a diagram of an example wireless communications system and an access network 100. The wireless communications system (also referred to as a wireless wide area network (WWAN) ) includes base stations 102, UEs 104, an Evolved Packet Core (EPC) 160, and another core network 190 (e.g., a 5G Core (5GC) ) . The base stations 102 may include macrocells (high power cellular base station) and/or small cells (low power cellular base station) . The macrocells include base stations. The small cells include femtocells, picocells, and microcells.

The base stations 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through backhaul links 132 (e.g., S1 interface) . The base stations 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN) ) may interface with core network 190 through backhaul links 184. In addition to other functions, the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages. The base stations 102 may communicate directly or indirectly (e.g., through the EPC 160 or core network 190) with each other over backhaul links 134 (e.g., X2 interface) . The backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102' may have a coverage area 110' that overlaps the coverage area 110 of one or more macro base stations 102. A network that includes both small cell and macrocells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) . The communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base stations 102 /UEs 104 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL) . The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .

Some UEs 104 may communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) . D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 /AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell 102' may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102' may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102', employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.

A base station 102, whether a small cell 102' or a large cell (e.g., macro base station) , may include an eNB, gNodeB (gNB) , or another type of base station. Some base stations, such as gNB 180, may operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and/or near mmW frequencies in communication with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as a millimeter wave or mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW /near mmW radio frequency band (e.g., 3 GHz –300 GHz) has extremely high path loss and a short range. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range.

The base station 180 may transmit a beamformed signal to the UE 104 in one or more transmit directions 182'. The UE 104 may receive the beamformed signal from the base station 180 in one or more receive directions 182” . The UE 104 may also transmit a beamformed signal to the base station 180 in one or more transmit directions. The base station 180 may receive the beamformed signal from the UE 104 in one or more receive directions. The base station 180 /UE 104 may perform beam training to determine the best receive and transmit directions for each of the base station 180 /UE 104. The transmit and receive directions for the base station 180 may or may not be the same. The transmit and receive directions for the UE 104 may or may not be the same.

The 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. The MME 162 may be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

The core network 190 may include an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may be in communication with a Unified Data Management (UDM) 196. The AMF 192 is the control node that processes the signaling between the UEs 104 and the core network 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 195. The UPF 195 provides UE IP address allocation as well as other functions. The UPF 195 is connected to the IP Services 197. The IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services.

The base station may also be referred to as a gNB, Node B, evolved Node B (eNB) , an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology. The base station 102 provides an access point to the EPC 160 or core network 190 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc. ) . The UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

Figure 2A shows an example of a first slot 200 within a 5G/NR frame structure. Figure 2B shows an example of DL channels 230 within a 5G/NR slot. Figure 2C shows an example of a second slot 250 within a 5G/NR frame structure. Figure 2D shows an example of UL channels 280 within a 5G/NR slot. The 5G/NR frame structure may be FDD in which, for a particular set of subcarriers (carrier system bandwidth) , slots within the set of subcarriers are dedicated for either DL or UL In other cases, the 5G/NR frame structure may be TDD in which, for a particular set of subcarriers (carrier system bandwidth) , slots within the set of subcarriers are dedicated for both DL and UL. In the examples shown in Figures 2A and 2C, the 5G/NR frame structure is configured as TDD, with slot 4 being configured with slot format 28 (with mostly DL) , where D indicates DL, U indicates UL, and X indicates that the slot is flexible for use between DL/UL, and slot 3 being configured with slot format 34 (with mostly UL) . While

slots

3 and 4 are shown with slot formats 34 and 28, respectively, any particular slot may be configured with any of the various available slot formats 0–61.

Slot formats

0 and 1 are all DL and all UL, respectively. Other slot formats 2–61 include a mix of DL, UL, and flexible symbols. UEs are configured with the slot format (dynamically through DL control information (DCI) , or semi-statically/statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI) . This format may also apply to a 5G/NR frame structure that is FDD.

Other wireless communication technologies may have a different frame structure and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms) . Each subframe may include one or more time slots. Subframes may also include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols. The symbols on DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also referred to as single carrier frequency-division multiple access (SC-FDMA) symbols) (for power limited scenarios; limited to a single stream transmission) . The number of slots within a subframe is based on the slot configuration and the numerology. For slot configuration 0, different numerologies μ 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots, respectively, per subframe. For slot configuration 1, different numerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, per subframe. Accordingly, for slot configuration 0 and numerology μ, there are 14 symbols/slot and 2μ slots/subframe. The subcarrier spacing and symbol length/duration are a function of the numerology. The subcarrier spacing may be equal to 2^μ*15 kKz, where μ is the numerology 0 to 5. As such, the numerology μ=0 has a subcarrier spacing of 15 kHz and the numerology μ=5 has a subcarrier spacing of 480 kHz. The symbol length/duration is inversely related to the subcarrier spacing. Figures 2A-2D provide an example of slot configuration 0 with 14 symbols per slot and numerology μ=0 with 1 slot per subframe. The subcarrier spacing is 15 kHz and symbol duration is approximately 66.7 μs.

A resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as a physical RB (PRB) ) that extends across 12 consecutive subcarriers and across a number of symbols. The intersections of subcarriers and symbols of the RB define multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme.

As illustrated in Figure 2A, some of the REs carry a reference (pilot) signal (RS) for the UE. In some configurations, one or more REs may carry a demodulation RS (DM-RS) (indicated as Rx for one particular configuration, where 100x is the port number, but other DM-RS configurations are possible) . In some configurations, one or more REs may carry a channel state information reference signal (CSI-RS) for channel measurement at the UE. The REs may also include a beam measurement RS (BRS) , a beam refinement RS (BRRS) , and a phase tracking RS (PT-RS) .

Figure 2B illustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) , each CCE including nine RE groups (REGs) , each REG including four consecutive REs in an OFDM symbol. A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE 104 to determine subframe or symbol timing and a physical layer identity. A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DM-RS. The physical broadcast channel (PBCH) , which carries a master information block (MIB) , may be logically grouped with the PSS and SSS to form a synchronization signal (SS) /PBCH block. The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN) . The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and paging messages.

As illustrated in Figure 2C, some of the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH) . The PUSCH DM-RS may be transmitted in the first one or two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. Although not shown, the UE may transmit sounding reference signals (SRS) . The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

Figure 2D illustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and HARQ ACK/NACK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.

Figure 3 shows a block diagram of an example base station 310 and UE 350 in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller/processor 375. The controller/processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller/processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, 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 UE measurement reporting; PDCP layer functionality associated with header compression /decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs) , error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) . The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially pre-coded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a respective spatial stream for transmission.

At the UE 350, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) . The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller/processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller/processor 359 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DL transmission by the base station 310, the controller/processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression /decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 350. IP packets from the controller/processor 375 may be provided to the EPC 160. The controller/processor 375 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations. Information to be wirelessly communicated (such as for LTE or NR based communications) is encoded and mapped, at the PHY layer, to one or more wireless channels for transmission.

As described above, 5G networks can be implemented in accordance with standalone (SA) or non-standalone (NSA) architectures. The 5G SA architecture includes a 5G core (5GC) and one or more base stations configured for 5G NR (such as gNBs) to provide 5G services to a user equipment (UE) . The 5GC provides native support for many of the improvements associated with 5G NR technology such as, for example, URLLC, network function virtualization (NFV) , network slicing, control and user plane separation (CUPS) , and multi-gigabit connectivity, among other examples. On the other hand, the 5G NSA architecture includes an evolved packet core (EPC) and a combination of base stations configured for 4G LTE and base stations configured for 5G NR (such as eNBs and gNBs, respectively) to provide 5G services to a UE. By integrating base stations configured for 5G NR into existing 4G LTE infrastructure, wireless networks implementing the 5G NSA architecture may support some of the improvements associated with 5G NR technology such as, for example, eMBB.

The 5G SA architecture offers many advantages over the 5G NSA architecture. However, the 5G NSA architecture provides a relatively fast and low-cost means for deploying 5G NR services by leveraging existing 4G LTE infrastructure. Moreover, because 4G LTE infrastructure is more mature, wireless networks based on the 5G NSA architecture may be more robust or reliable than newer wireless networks based on the 5G SA architecture. Thus, it may be desirable for a 5G-capable UE to dynamically adapt its wireless radios, under various circumstances, to receive 5G services from wireless networks implementing SA or NSA 5G network architectures.

Various implementations relate generally to self-adaptation in wireless networks. Some implementations more specifically relate to dynamically adapting a multi-subscriber UE to wireless networks implemented in accordance with SA and NSA 5G network architectures. The UE may initially register first and second subscriber identities with a 5G SA network. As used herein, the term “5G SA network” may refer to any wireless network implemented in accordance with the 5G SA architecture or any 5G network including a 5GC. In some implementations, the UE may detect an abnormality with the 5G SA network if, after a number of attempts in a relative short duration, the UE fails to establish or maintain a PDU session between the network and a wireless radio associated with the first subscriber identity. In some implementations, the UE may selectively deregister the second subscriber identity from the 5G SA network and register the second subscriber identity with a 5G NSA network based on the detected abnormality. As used herein, the term “5G NSA network” may refer to any wireless network implemented in accordance with the 5G NSA architecture or any 5G network including an EPC.

Figure 4 shows an example wireless communication system 400 according to some implementations. The wireless communication system 400 includes a UE 402, a first wireless network 410, and a second wireless network 420. In the example of Figure 4, the UE 402 may be a 5G-capable UE associated with multiple subscriber identities (referred to herein as a “multi-subscriber UE” ) . In some implementations, the UE 402 may be one example of the

UEs

104 or 350 of Figures 1 and 3, respectively. In some implementations, the first wireless network 410 may be one example of a 5G SA network and the second wireless network 420 may be one example of a 5G NSA network.

The first wireless network 410 includes a number of

base stations

412 and 414 configured for 5G NR (referred to herein as “NR base stations” ) and a 5GC core network 416. In some implementations, each of the

base stations

412 and 414 may be one example of the

base stations

102 or 310 of Figures 1 and 3, respectively. In some implementations, the core network 416 may be one example of the of core network 190 of Figure 1. Although the first wireless network 410 is shown to include two

NR base stations

412 and 414, a 5G SA network may include fewer or more base stations than those depicted in Figure 4. Each of the

NR base stations

412 and 414 is connected to the core network 416 via a respective user interface (U-I/F) and a respective control interface (C-I/F) . Accordingly, each of the

NR base stations

412 and 414 can communicate user-plane traffic (which includes user data) and control-plane traffic (which includes control signals) with the core network 416. In some implementations, the UE 402 may communicate with the core network 416 via any one of the

NR base stations

412 or 414.

The second wireless network 420 includes a base station 422 configured for 4G LTE (referred to herein as an “LTE base station” ) , an NR base station 424, and an EPC core network 426. In some implementations, each of the

base station

422 and 424 may be one example of the

base stations

102 or 310 of Figures 1 and 3, respectively. In some implementations, the core network 426 may be one example of the EPC 160 of Figure 1. Although the second wireless network 420 is shown to include one LTE base station 422 and one NR base station 424, a 5G NSA network may include more LTE or NR base stations than those depicted in Figure 4. The LTE base station 422 is connected to the core network 426 via a user interface and a control interface and the NR base station 424 is connected to the core network 426 via a user interface only. Accordingly, the LTE base station 422 can communicate user-plane traffic and control-plane traffic with the core network 426 while the NR base station 424 is limited to communicating user-plane traffic with the core network 426. In some implementations, the UE 402 may communicate with the core network 426 via a combination of the LTE base station 422 and the NR base station 424.

E-UTRAN New Radio –Dual Connectivity (ENDC) enables a UE to communicate using multiple RATs (such as 4G LTE and 5G NR) , concurrently. ENDC may allow the UE 402 to register with the second wireless network 420 through the LTE base station 422 and receive 5G services via the NR base station 424. In this configuration, the LTE base station 422 may serve as an anchor to the second wireless network 420 for the UE 402. More specifically, the LTE base station 422 may operate as a master node (MN) and the NR base station 424 may operate as a secondary node (SN) . For example, the LTE base station 422 may “add” the NR base station 424 to a secondary cell group (SCG) in response to detecting a Dual-Connectivity with New Radio (DCNR) bit asserted by the UE 402 when registering with the wireless network 420. When the UE 402 is configured for ENDC, the LTE base station 422 may process all control-plane traffic on behalf of the UE 402 and the NR base station 424 may process some or all user-plane traffic on behalf of the UE 402. In some configurations, the user-plane traffic may be distributed among the

base station

422 and 424 to further increase data throughput in the wireless network 420.

As described above, 5G SA networks (such as the first wireless network 410) provide native support for many 5G, some of which may not be supported by 5G NSA networks (such as the second wireless network 420) . However, some 5G SA networks may exhibit abnormalities that can prevent a UE from maintaining a PDU session with the network. For example, in some instances, a UE may establish a PDU session with the 5G SA network and may receive a command to release the PDU session shortly after its establishment, giving the UE little or no time to receive any data services from the network. The PDU session release command may indicate “regular deactivation” (or cause #36) as the cause of the termination of the PDU session. A UE operating in accordance with existing 5G standards may attempt to establish another PDU session with the 5G SA network in response to receiving a PDU session release command. Because many 5G SA networks are still under development, such abnormalities in 5G SA networks may prevent 5G-capable UEs from receiving 5G services for a relatively long duration.

Aspects of the present disclosure enable a UE to detect abnormalities in a 5G SA network that can prevent the UE from maintaining a PDU session with the network. In some implementations, a UE may detect an abnormality with a 5G SA network based on a number of PDU session release commands it receives from the network over a threshold duration. For example, the UE may determine the 5G SA network is performing abnormally if it receives a relatively large number of PDU session release commands from the network (in response to respective PDU session requests by the UE) over a relatively short period of time. In some implementations, the UE may change the registration of one or more of its subscriber identities from the 5G SA network to a 5G NSA network responsive to detecting the abnormality. This allows the UE to receive 5G services faster or sooner than would otherwise be possible according to existing 5G standards. Still further, in some implementations, the UE may change the registration of its subscriber identities from the 5G NSA network back to the 5G SA network after a threshold duration has elapsed. In this manner, the UE may periodically check the 5G SA network to determine whether the abnormality has been resolved.

Some multi-subscriber UEs may be operable in a dual-SIM dual-active (DSDA) or dual-SIM dual-standby (DSDS) configuration. In the DSDA configuration, each of the subscriber identities may be associated with a different wireless radio (or allocated a different set of radio resources) that may operate independently of one another. For example, two or more of the wireless radios may transmit and receive wireless communications, concurrently, on behalf of two or more subscriber identities. In the DSDS configuration, multiple subscriber identities may be associated with the same wireless radio (or allocated the same set of radio resources) . As a result, only one of the subscriber identities may be active at a time. In some instances, two or more subscriber identities of a multi-subscriber UE may be registered to the same 5G SA network. In some implementations, the UE may be configured to detect abnormalities with the 5G SA network based on a number of PDU session release commands it receives from the network on behalf of each of the subscriber identities.

Aspects of the present disclosure recognize that some abnormalities in a 5G SA network may prevent a UE from maintaining a PDU session with the network on behalf of any of its subscriber identities. Thus, in some implementations, the detection of an abnormality on behalf of a first subscriber identity of a multi-subscriber UE may trigger the UE to selectively change the registration of a second subscriber identity from the 5G SA network to a 5G NSA network. In some aspects, the UE may change the registration of the second subscriber identity from the 5G SA network to the 5G NSA network responsive to the detection of the abnormality. In some other aspects, the UE may attempt to establish a PDU session with the 5G SA network on behalf of the second subscriber identity responsive to the detection of the abnormality. The UE may subsequently change the registration of the second subscriber identity from the 5G SA network to the 5G NSA network only if the PDU session fails or is terminated by the 5G SA network. In some implementations, the UE may change the registration of the second subscriber identity from the 5G NSA network back to the 5G SA network after a threshold duration has elapsed.

Figure 5 shows a sequence diagram 500 depicting an example message exchange between a multi-subscriber UE 502 and base stations associated with

multiple wireless networks

510 and 520 according to some implementations. In some implementations, the UE 502 may be one example of the UE 402 of Figure 4. In the example of Figure 5, the UE 502 is associated with multiple subscriber identities Sub1 and Sub2, and is capable of operating in a DSDA or DSDS configuration. In some implementations, the wireless network 510 may be one example of a 5G SA network such as the first wireless network 410 of Figure 4. In some implementations, the wireless network 520 may be one example of a 5G NSA network such as the second wireless network 420 of Figure 4.

The UE 502 initially registers the subscriber identities Sub1 and Sub2 with the 5G SA network 510. During the registration process, for each subscriber identity Sub1 and Sub2, the UE 502 may transmit a registration request to an NR base station associated with the 5G SA network 510 and may receive a response from the NR base station indicating acceptance of the registration request. In sone implementations, after completing the registration process, the UE 502 initiates a timer and establishes a PDU session with the 5G SA network 510 on behalf of subscriber identity Sub1. During the PDU session establishment process, the UE 502 may transmit a PDU session establishment request to the NR base station associated with the 5G SA network 510 and may receive a response from the NR base station indicating acceptance of the PDU session establishment request. In the example of Figure 5, the UE 502 receives a PDU session release command from the 5G SA network 510 shortly after establishing the PDU session on behalf of subscriber identity Sub1. In some implementations, the UE 502 may increment a counter associated with subscriber identity Sub1 in response to receiving the PDU session release command from the 5G SA network 510.

In some implementations, the UE 502 may detect abnormalities with the 5G SA network 510 based on a count value of the counter and an elapsed duration of the timer. For example, the UE 502 may determine that the 5G SA network 510 is performing abnormally if a value of the counter is greater than or equal to a threshold count value (such as 5) within a threshold duration (such as 60 seconds) . In some aspects, the UE 502 may attempt another PDU session with the 5G SA network 510, on behalf of subscriber identity Sub1, if the value of the counter has not yet reached the threshold count value. In other words, the UE 502 may continue to increment the counter associated with subscriber identity Sub1 at the termination of each PDU session until the value of the counter reaches the threshold count value. In the example of Figure 5, the UE 502 determines, after a number of failed PDU sessions, that the value of the counter associated with subscriber identity Sub1is equal to (or greater than) the threshold count value and the elapsed duration of the timer has not exceeded the threshold duration. Accordingly, the UE 502 may detect an abnormality with the 5G SA network 510 that is preventing the UE 502 from maintaining a PDU session.

In some implementations, the UE 502 may deregister subscriber identity Sub1 from the 5G SA network 510 in response to detecting the abnormality. During the deregistration process, the UE 502 may transmit a deregistration request to the NR base station associated with the 5G SA network 510 and may receive a response from the NR base station indicating acceptance of the deregistration request. After deregistering subscriber identity Sub1 from the 5G SA network 510, the UE 502 may proceed to register subscriber identity Sub1 with the 5G NSA network 520. During the registration process, UE 502 may transmit an attach request (indicating support for DCNR) to an LTE base station associated with the 5G NSA network 520 and may receive a response from the LTE base station indicating acceptance of the attach request. Further, the LTE base station may add an NR base station as a secondary node, via an SCG addition procedure, in response to determining that the UE 502 supports DCNR. The LTE base station may thus operate as a master node or anchor for communications between the UE 502 and the 5G NSA network 520.

In some implementations, the UE 502 may initiate a countdown timer (not shown for simplicity) after registering subscriber identity Sub1 with the 5G NSA network 520. When the countdown timer expires, the UE 502 may deregister subscriber identity Sub1 from the 5G NSA network 520 and re-register subscriber identity Sub1 with the 5G SA network 510. In some implementations, the UE 502 may selectively change the registration of subscriber identity Sub2 from the 5G SA network 510 to the 5G NSA network 520 based on the detection of the abnormality. For example, in some aspects, the UE 502 may assert or activate an NSA synchronization (NSA_Sync) flag or signal in response to detecting the abnormality with the 5G SA network 510 on behalf of subscriber identity Sub1.

Figure 6 shows a sequence diagram 600 depicting an example message exchange between a multi-subscriber UE 602 and base stations associated with

multiple wireless networks

610 and 620 according to some implementations. In some implementations, the UE 602 may be one example of the

UEs

402 or 502 of Figures 4 and 5, respectively. In the example of Figure 6, the UE 602 is associated with multiple subscriber identities Sub1 and Sub2, and is capable of operating in a DSDA or DSDS configuration. In some implementations, the wireless network 610 may be one example of a 5G SA network such as the first wireless network 410 or the 5G SA network 510 of Figures 4 and 5, respectively. In some implementations, the wireless network 620 may be one example of a 5G NSA network such as the second wireless network 420 or the 5G NSA network 520 of Figures 4 and 5, respectively.

In the example of Figure 6, subscriber identity Sub2 is initially registered with the 5G SA network 610 when the UE 602 asserts or activates an NSA synchronization flag or signal on behalf of subscriber identity Sub1. As described with reference to Figure 5, assertion of the NSA synchronization flag or signal may indicate an abnormality has been detected in the 5G SA network 610. In some implementations, the UE 602 deregisters subscriber identity Sub2 from the 5G SA network 610 in response to asserting the NSA synchronization flag. During the deregistration process, the UE 602 may transmit a deregistration request to an NR base station associated with the 5G SA network 610 and may receive a response from the NR base station indicating acceptance of the deregistration request.

After deregistering subscriber identity Sub2 from the 5G SA network 610, the UE 602 may proceed to register subscriber identity Sub2 with the 5G NSA network 620. During the registration process, the UE 602 may transmit an attach request (indicating support for DCNR) to an LTE base station associated with the 5G NSA network 620 and may receive a response from the LTE base station indicating acceptance of the attach request. The LTE base station may add an NR base station as a secondary node, via an SCG addition procedure, in response to determining that the UE 602 supports DCNR. The LTE base station may thus operate as a master node or anchor for communications between the UE 602 and the 5G NSA network 620.

In some implementations, the UE 602 may initiate a countdown timer after registering subscriber identity Sub2 with the 5G NSA network 620. When the countdown timer expires, the UE 602 may deregister subscriber identity Sub2 from the 5G NSA network 620. During the deregistration process, the UE 602 may transmit a detach request to the LTE base station associated with the 5G NSA network 620 and may receive a response from the LTE base station indicating acceptance of the detach request. Thereafter, the UE 602 may register subscriber identity Sub2 with the 5G SA network 610 once more.

Figure 7 shows a sequence diagram 700 depicting an example message exchange between a multi-subscriber UE 702 and base stations associated with

multiple wireless networks

710 and 720 according to some implementations. In some implementations, the UE 702 may be one example of the

UEs

402 or 502 of Figures 4 and 5, respectively. In the example of Figure 7, the UE 702 is associated with multiple subscriber identities Sub1 and Sub2, and is capable of operating in a DSDA or DSDS configuration. In some implementations, the wireless network 710 may be one example of a 5G SA network such as the first wireless network 410 or the 5G SA network 510 of Figures 4 and 5, respectively. In some implementations, the wireless network 720 may be one example of a 5G NSA network such as the second wireless network 420 or the 5G NSA network 520 of Figures 4 and 5, respectively.

In the example of Figure 7, subscriber identity Sub2 is initially registered with the 5G SA network 710 when the UE 702 asserts or activates an NSA synchronization flag or signal on behalf of subscriber identity Sub1. As described with reference to Figure 5, assertion of the NSA synchronization flag or signal may indicate an abnormality has been detected in the 5G SA network 710. In some implementations, the UE 702 may attempt a PDU session with the 5G SA network 710, on behalf of subscriber identity Sub2, in response to detecting the NSA synchronization flag. During the PDU session establishment process, the UE 702 may transmit a PDU session establishment request to an NR base station associated with the 5G SA network 710 and may receive a response from the NR base station indicating acceptance of the PDU session establishment request.

If the UE 702 can maintain the PDU session, subscriber identity Sub2 may remain registered with the 5G SA network 710. However, if the UE 702 receives a PDU session release command from the 5G SA network 710, the UE 702 may proceed to deregister subscriber identity Sub2 from the 5G SA network 710. During the deregistration process, the UE 702 may transmit a deregistration request to the NR base station associated with the 5G SA network 710 and may receive a response from the NR base station indicating acceptance of the deregistration request.

After deregistering subscriber identity Sub2 from the 5G SA network 710, the UE 702 may proceed to register subscriber identity Sub2 with the 5G NSA network 720. During the registration process, the UE 702 may transmit an attach request (indicating support for DCNR) to an LTE base station associated with the 5G NSA network 720 and may receive a response from the LTE base station indicating acceptance of the attach request. The LTE base station may add an NR base station as a secondary node, via an SCG addition procedure, in response to determining that the UE 702 supports DCNR. The LTE base station may thus operate as a master node or anchor for communications between the UE 702 and the 5G NSA network 720.

In some implementations, the UE 702 may initiate a countdown timer after registering subscriber identity Sub2 with the 5G NSA network 720. When the countdown timer expires, the UE 702 may deregister subscriber identity Sub2 from the 5G NSA network 720. During the deregistration process, the UE 702 may transmit a detach request to the LTE base station associated with the 5G NSA network 720 and may receive a response from the LTE base station indicating acceptance of the detach request. Thereafter, the UE 702 may register subscriber identity Sub2 with the 5G SA network 710 once more.

Figure 8A shows a flowchart illustrating an example process 800 for wireless communication that supports self-adaptation for multi-subscriber UEs in wireless networks according to some implementations. In some implementations, the process 800 may be performed by a wireless communication device operating as or within a UE, such as one of the

UEs

104, 350, or 402 described above with respect to Figures 1, 3, and 4, respectively.

In some implementations, the process 800 begins in block 801 with registering first and second subscriber identities with a first network, where the first network including a 5G core (5GC) . In block 802, the process 800 proceeds with establishing a first PDU session between the first network and a wireless radio associated with the first subscriber identity. In block 803, the process 800 proceeds with initiating a timer associated with the first PDU session prior to establishing the first PDU session. In block 804, the process 800 proceeds with receiving, from the first network, a command to release the first PDU session. In block 805, the process 800 proceeds with detecting an abnormality with the first network based on the command to release the first PDU session and an elapsed duration of the timer. In block 806, the process 800 proceeds with selectively changing the registration of the second subscriber identity from the first network to a second network based on the detected abnormality, where the second network includes an evolved packet core (EPC) .

Figure 8B shows a flowchart illustrating an example process 810 for wireless communication that supports self-adaptation for multi-subscriber UEs in wireless networks according to some implementations. In some implementations, the process 810 may be performed by a wireless communication device operating as or within a UE, such as one of the

UEs

With reference for example to Figure 8A, the process 810 may be a more detailed implementation of the operation for selectively changing the registration of the second subscriber identity in block 806 of the process 800. For example, the process 810 may begin after the detection of the abnormality with the first network in block 805. In some implementations, the process 810 may begin in block 811 with establishing a second PDU session between the first network and a wireless radio associated with the second subscriber identity responsive to detecting the abnormality. In some implementations, the process 810 may proceed to block 812 with receiving a command to release the second PDU session. In block 813, the process 810 proceeds with deregistering the second subscriber identity from the first network. In block 814, the process 810 proceeds with registering the second subscriber identity with the second network.

Figure 9 shows a flowchart illustrating an example process 900 for wireless communication that supports self-adaptation for multi-subscriber UEs in wireless networks according to some implementations. In some implementations, the process 900 may be performed by a wireless communication device operating as or within a UE, such as one of the

UEs

In some implementations, the process 900 begins in block 902 with registering a first subscriber identity with a first network, where the first network includes a 5G core (5GC) . In block 904, the process 900 proceeds with detecting an abnormality with the first network based on communications between the first network and a wireless radio associated with a second subscriber identity. In block 906, the process 900 proceeds with selectively changing the registration of the first subscriber identity from the first network to a second network based on the detected abnormality, where the second network includes an evolved packet core (EPC) .

Figure 10 shows a block diagram of an example UE 1000 according to some implementations. In some implementations, the UE 1000 is configured to perform any of the

processes

800, 810, or 900 described above with reference to Figures 8A, 8B, and 9, respectively. The UE 1000 can be an example implementation of the UE 350 described above with reference to Figure 3. For example, the UE 1000 can be a chip, SoC, chipset, package or device that includes at least one processor and at least one modem (for example, a Wi-Fi (IEEE 802.11) modem or a cellular modem) .

The UE 1000 includes a reception component 1010, a communication manager 1020, and a transmission component 1030. The communication manager 1020 further includes a network registration component 1022, a PDU session establishment component 1024, an abnormality detection component 1026, and a network switching component 1028. Portions of one or more of the components 1022–1028 may be implemented at least in part in hardware or firmware. In some implementations, at least some of the

components

1022, 1024, 1026, or 1028 are implemented at least in part as software stored in a memory (such as the memory 360) . For example, portions of one or more of the

components

1022, 1024, 1026, and 1028 can be implemented as non-transitory instructions (or “code” ) executable by a processor (such as the controller/processor 359) to perform the functions or operations of the respective component.

The reception component 1010 is configured to receive RX signals on behalf of a plurality of subscriber identities associated with the UE 1000. The communication manager 1020 is configured to control or manage communications with one or more wireless networks on behalf of the plurality of subscriber identities. In some implementations, the network registration component 1022 may register the first and second wireless subscriber identities of the plurality of subscriber identities with a first network, where the first network includes a 5G core (5GC) ; the PDU session establishment component 1024 may establish a first PDU session between the first network and a wireless radio associated with the first subscriber identity; the abnormality detection component 1026 may initiate a timer associated with the first PDU session prior to establishing the first PDU session, and may detect an abnormality with the first network based on reception of a command to release the first PDU session and an elapsed duration of the timer; and the network switching component 1028 may selectively change the registration of the second subscriber identity from the first network to a second network based on the detected abnormality, where the second network includes an evolved packet core (EPC) . The transmission component 1030 is configured to transmit TX signals on behalf of the plurality of subscriber identities associated with the UE 1000.

As used herein, a phrase referring to “at least one of” or “one or more of” a list of items refers to any combination of those items, including single members. For example, “at least one of: a, b, or c” is intended to cover the possibilities of: a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a and b and c.

The various illustrative components, logic, logical blocks, modules, circuits, operations and algorithm processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware or software, including the structures disclosed in this specification and the structural equivalents thereof. The interchangeability of hardware, firmware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and processes described above. Whether such functionality is implemented in hardware, firmware or software depends upon the particular application and design constraints imposed on the overall system.

Various modifications to the implementations described in this disclosure may be readily apparent to persons having ordinary skill in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.

Additionally, various features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. As such, although features may be described above as acting in particular combinations, and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flowchart or flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In some circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Claims

A method of wireless communication by a user equipment (UE) associated with a plurality of subscriber identities, comprising:

registering first and second subscriber identities of the plurality of subscriber identities with a first network, the first network including a fifth generation (5G) core (5GC) ;

establishing a first protocol data unit (PDU) session between the first network and a wireless radio associated with the first subscriber identity;

initiating a timer associated with the first PDU session prior to establishing the first PDU session;

receiving, from the first network, a command to release the first PDU session;

detecting an abnormality with the first network based on the command to release the first PDU session and an elapsed duration of the timer; and

selectively changing the registration of the second subscriber identity from the first network to a second network based on the detected abnormality, the second network including an evolved packet core (EPC) .
The method of claim 1, wherein the first subscriber identity is associated with a first wireless radio and the second subscriber identity is associated with a second wireless radio.
The method of claim 1, wherein the first network comprises a 5G standalone (SA) architecture and the second network comprises a 5G non-standalone (NSA) architecture.
The method of claim 1, wherein the detecting of the abnormality comprises:

incrementing a counter responsive to receiving the command to release the first PDU session; and

determining whether a value of the counter is equal to or greater than a threshold value, the abnormality being detected based on determining that the value of the counter is equal to or greater than the threshold value and determining that the duration of the timer has not exceeded a threshold duration.
The method of claim 4, further comprising:

establishing a second PDU session between the first network and the wireless radio associated with the first subscriber identity;

receiving, from the first network, a command to release the second PDU session; and

incrementing the counter responsive to receiving the command to release the second PDU session.
The method of claim 1, wherein the selective changing of the registration of the second subscriber identity comprises:

deregistering the second subscriber identity from the first network responsive to detecting the abnormality; and

registering the second subscriber identity with the second network.
The method of claim 1, further comprising:

establishing a second PDU session between the first network and a wireless radio associated with the second subscriber identity responsive to detecting the abnormality.
The method of claim 7, further comprising:

receiving a command to release the second PDU session; and

deregistering the second subscriber identity from the first network responsive to receiving the command to release the second PDU session, wherein the selective changing of the registration of the second subscriber identity comprises registering the second subscriber identity with the second network based on detecting the abnormality and based on the deregistration.
The method of claim 1, further comprising:

initiating a countdown timer responsive to changing the registration of the second subscriber identity from the first network to the second network; and

changing the registration of the second subscriber identity from the second network back to the first network responsive to expiration of the countdown timer.
The method of claim 1, further comprising:

changing the registration of the first subscriber identity from the first network to the second network responsive to detecting the abnormality.
The method of claim 10, further comprising:

initiating a countdown timer responsive to the changing the registration of the first subscriber identity from the first network to the second network; and

changing the registration of the first subscriber identity from the second network to the first network responsive to expiration of the countdown timer.
A user equipment (UE) comprising:

at least one modem;

at least one processor communicatively coupled with the at least one modem; and

at least one memory communicatively coupled with the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, causes the wireless communication device to perform the operations of claims 1–11.
A method of wireless communication by a user equipment (UE) associated with a plurality of subscriber identities, comprising:

registering a first subscriber identity of the plurality of subscriber identities with a first network, the first network including a fifth generation (5G) core (5GC) ;

detecting an abnormality with the first network based on communications between the first network and a wireless radio associated with a second subscriber identity of the plurality of subscriber identities; and

selectively changing the registration of the first subscriber identity from the first network to a second network based on the detected abnormality, the second network including an evolved packet core (EPC) .
The method of claim 13, wherein the first subscriber identity is associated with a first wireless radio and the second subscriber identity is associated with a second wireless radio.
The method of claim 13, wherein the first network comprises a 5G standalone (SA) architecture and the second network comprises a 5G non-standalone (NSA) architecture.
The method of claim 13, wherein the selective changing of the registration of the first subscriber identity comprises:

deregistering the first subscriber identity from the first network responsive to detecting the abnormality; and

registering the first subscriber identity with the second network.
The method of claim 13, further comprising:

establishing a second PDU session between the first network and a wireless radio associated with the second subscriber identity responsive to detecting the abnormality.
The method of claim 17, further comprising:

receiving a command to release the second PDU session;

deregistering the first subscriber identity from the first network responsive to receiving the command to release the second PDU session, wherein the selective changing of the registration of the first subscriber identity comprises registering the first subscriber identity with the second network based on detecting the abnormality and based on the deregistration.
The method of claim 13, further comprising:

initiating a countdown timer responsive to changing the registration of the first subscriber identity from the first network to the second network; and

changing the registration of the first subscriber identity from the second network back to the first network responsive to expiration of the countdown timer.
A user equipment (UE) comprising:

at least one modem;

at least one processor communicatively coupled with the at least one modem; and

at least one memory communicatively coupled with the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, causes the wireless communication device to perform the operations of claims 13–19.