WO2021258384A1

WO2021258384A1 - Optimizations for dual-sim user equipment in case of unsuccessful service registration

Info

Publication number: WO2021258384A1
Application number: PCT/CN2020/098304
Authority: WO
Inventors: Jian Li; Hao Zhang; Fojian ZHANG; Haibo Liu; Chaofeng HUI; Tianya LIN; Yuankun ZHU
Original assignee: Qualcomm Incorporated
Priority date: 2020-06-26
Filing date: 2020-06-26
Publication date: 2021-12-30

Abstract

Aspects of the disclosure relate to an efficient approach to perform a service registration by a user equipment (UE) configured to use multiple subscriptions. In particular, the UE performs a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area. If the UE determines that the first service registration using the first subscription has failed, the UE further triggers a cell reselection to a second network node using a second subscription, where the second network node is associated with a second tracking area different from the first tracking area. The UE further performs a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription.

Description

OPTIMIZATIONS FOR DUAL-SIM USER EQUIPMENT IN CASE OF UNSUCCESSFUL SERVICE REGISTRATION

TECHNICAL FIELD

The technology discussed below relates generally to wireless communication systems, and more particularly, to service registration using a user equipment configured to utilize multiple subscriptions.

INTRODUCTION

A user equipment (UE) often uses a subscription to connect to a service network, which provides one or more services such as a voice call service or a data service. For example, a subscription used by the UE may be associated with a subscription module or device such as a subscription identification module (SIM) that the UE accesses to use the subscription. With development of the subscription based services, a UE that is capable of using two or more subscriptions are increasingly used. In one example, a UE may implement a dual SIM that allows the UE to connect to a service network using two different subscriptions respectively provided by two SIMs. Various Improvements for a UE configured to use multiple subscriptions are being studied.

BRIEF SUMMARY OF SOME EXAMPLES

The following presents a simplified summary of one or more aspects of the present disclosure, in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in a simplified form as a prelude to the more detailed description that is presented later.

Various aspects pertain to ways to efficiently perform a service registration by a user equipment configured to communicate using multiple subscriptions. In one exemplary approach, a user equipment (UE) configured to communicate using multiple subscriptions performs a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area. The UE further determines that the first service registration using the first subscription has failed. The UE further triggers a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, the second network node being associated with a second tracking area different from the first tracking area. The UE further performs a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription.

In one example, a method of wireless communication by a UE configured to communicate using multiple subscriptions is disclosed. The method includes performing a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area, determining that the first service registration using the first subscription has failed, triggering a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, the second network node being associated with a second tracking area different from the first tracking area, and performing a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription. In an aspect, the method may further include performing data communication based on the second service registration using the second subscription subsequent to performing the second service registration. In an aspect, the method may further include preventing the UE from selecting the first network node for service registration using the second subscription in response to determining that the first service registration has failed. In an aspect, a radio access technology (RAT) of the first network node is same as a RAT of the second network node. In this aspect, the RAT of the first network node and the RAT of the second network node are based on 5G New Radio (NR) technology, and the first and second network nodes are general node Bs (gNBs) .

In an aspect, the method may further include performing a cell search for a network node associated with a tracking area different from the first tracking area in response to determining that the first service registration has failed. In this aspect, the cell reselection to the second network node may be triggered when the cell search finds the second network node.

In an aspect, the method may further include selecting the second network node among a plurality of network nodes based on priority values respectively associated with the plurality of network nodes and in response to determining that the first service registration has failed. In this aspect, the cell reselection to the second network node using the second subscription may be triggered subsequent to selecting the second network node. In such an aspect, the priority values may be based on signal strength values respectively associated with the plurality of network nodes.

In an aspect, the first service registration may be performed using a first packet session established with the first network node using the first subscription. In this aspect, the method may further include establishing a second packet session with the second network node using the second subscription in response to triggering the cell reselection to the second network using the second subscription, wherein the second service registration is performed using the second packet session.

In an aspect, the method may include generating or updating a forbidden tracking area list by adding the first tracking area associated with the first network node to the forbidden tracking area list in response to determining that the first registration with the first network node has failed. In this aspect, triggering the cell reselection to the second network node using the second subscription may be based on the forbidden tracking area list. In such an aspect, triggering the cell reselection to the second network node using the second subscription may include providing the forbidden tracking area list to the second subscription, wherein the cell reselection to the second network node using the second subscription is triggered in response to the forbidden tracking area list provided to the second subscription.

In an aspect, the method may further include triggering a cell reselection to the second network node using the first subscription in response to determining that the first service registration has failed, performing a subsequent service registration using the first subscription to register with the service network or the different service network via the second network node in response to triggering the cell reselection to the second network node using the first subscription, and determining whether the subsequent service registration is successful. In this aspect, the cell reselection to the second network node using the second subscription may be triggered in response to determining that the first service registration has failed and that the subsequent service registration is successful. In such an aspect, the method may further include determining that the subsequent service registration has failed, and triggering a cell reselection to a third network node using the second subscription in response to determining that the subsequent service registration has failed, the third network node being associated with a third tracking area different from the first and second tracking areas.

In an aspect, the method may further include determining that the second service registration has failed, triggering a cell reselection to a third network node using the first subscription in response to determining that the second service registration has failed, the third network node being associated with a third tracking area different from the first and second tracking areas, performing a third service registration using the first subscription to register with the service network via the third network node in response to triggering the cell reselection to the third network node using the first subscription.

In another example, a UE for wireless communication and configured to communicate using multiple subscriptions is disclosed. The UE includes at least one processor, a transceiver communicatively coupled to the at least one processor; and a memory communicatively coupled to the at least one processor. The at least one processor is configured to perform a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area, determine that the first service registration using the first subscription has failed, trigger a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, the second network node being associated with a second tracking area different from the first tracking area, and perform a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription.

In another example, a non-transitory processor-readable storage medium having instructions stored thereon for a UE configured to communicate using multiple subscriptions is disclosed. The instructions, when executed by a processing circuit, cause the processing circuit to perform a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area, determine that the first service registration using the first subscription has failed, trigger a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, the second network node being associated with a second tracking area different from the first tracking area, and perform a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription.

In another example, a UE for wireless communication and configured to communicate using multiple subscriptions is disclosed. The UE includes means for performing a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area; means for determining that the first service registration using the first subscription has failed; means for triggering a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, the second network node being associated with a second tracking area different from the first tracking area; and means for performing a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription.

These and other aspects of the invention will become more fully understood upon a review of the detailed description, which follows. Other aspects, features, and embodiments will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary embodiments in conjunction with the accompanying figures. While features may be discussed relative to certain embodiments and figures below, all embodiments can include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments discussed herein. In similar fashion, while exemplary embodiments may be discussed below as device, system, or method embodiments it should be understood that such exemplary embodiments can be implemented in various devices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a wireless communication system according to some aspects.

FIG. 2 is a block diagram illustrating an example of a 5G wireless communication system (5GS) .

FIG. 3 is a conceptual illustration of an example of a radio access network according to some aspects.

FIG. 4 is a block diagram illustrating a wireless communication system supporting multiple-input multiple-output (MIMO) communication.

FIG. 5 is an example diagram illustrating an example process of retrying a service registration after an unsuccessful service registration.

FIG. 6 is an example diagram illustrating communications between a user equipment configured to communicate using multiple subscriptions and various network nodes to perform a service registration, according to an aspect of the disclosure.

FIG. 7 is an example diagram illustrating a process for service registration with a user equipment configured to communicate using multiple subscriptions, according to an aspect of the disclosure.

FIG. 8 is a block diagram conceptually illustrating an example of a hardware implementation for a user equipment according to some aspects of the disclosure.

FIG. 9 is a flow chart illustrating an exemplary process for wireless communication by a user equipment configured to communicate using multiple subscriptions, according to some aspects of the disclosure.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

A user equipment (UE) may be configured to use multiple subscriptions, such as a first subscription and a second subscription, to provide a service. The UE may communicate using the multiple subscriptions via respective multiple subscription modules. The UE may attempt to perform a first service registration with a service network using the first subscription via a first network node associated with a tracking area. Even if the first service registration using the first subscription via the first network node fails, the UE may waste time and resources trying to perform a service registration using another subscription via the first network node, which is likely to fail. Therefore, a more efficient approach for performing a service registration is desired for the UE configured to communicate using multiple subscriptions.

In an aspect of the disclosure, if the UE determines that the first service registration using the first subscription via the first network node has failed, the UE may trigger a reselection to a second network node associated with a different tracking area using the second subscription, and perform a second service registration with the service network or a different service network using the second subscription via the second network node. As such, when the first service registration fails, the UE utilizes the second network node for the second subscription to perform the second service registration, instead of wasting time and resources at an attempt to perform a service registration using the second subscription via the first network node, which is likely to fail.

While aspects and embodiments are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases may come about in many different arrangements and scenarios. Innovations described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, packaging arrangements. For example, embodiments and/or uses may come about via integrated chip embodiments and other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, AI-enabled devices, etc. ) . While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described innovations may occur. Implementations may range a spectrum from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregate, distributed, or OEM devices or systems incorporating one or more aspects of the described innovations. In some practical settings, devices incorporating described aspects and features may also necessarily include additional components and features for implementation and practice of claimed and described embodiments. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including antenna, RF-chains, power amplifiers, modulators, buffer, processor (s) , interleaver, adders/summers, etc. ) . It is intended that innovations described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, end-user devices, etc. of varying sizes, shapes and constitution.

The various concepts presented throughout this disclosure may be implemented across a broad variety of telecommunication systems, network architectures, and communication standards. Referring now to FIG. 1, as an illustrative example without limitation, various aspects of the present disclosure are illustrated with reference to a wireless communication system 100. The wireless communication system 100 includes three interacting domains: a core network 102, a radio access network (RAN) 104, and a user equipment (UE) 106. By virtue of the wireless communication system 100, the UE 106 may be enabled to carry out data communication with an external data network 110, such as (but not limited to) the Internet.

The RAN 104 may implement any suitable wireless communication technology or technologies to provide radio access to the UE 106. As one example, the RAN 104 may operate according to 3 ^rd Generation Partnership Project (3GPP) New Radio (NR) specifications, often referred to as 5G. As another example, the RAN 104 may operate under a hybrid of 5G NR and Evolved Universal Terrestrial Radio Access Network (eUTRAN) standards, often referred to as LTE. The 3GPP refers to this hybrid RAN as a next-generation RAN, or NG-RAN. Of course, many other examples may be utilized within the scope of the present disclosure.

As illustrated, the RAN 104 includes a plurality of base stations 108. Broadly, a base station is a network element in a radio access network responsible for radio transmission and reception in one or more cells to or from a UE. In different technologies, standards, or contexts, a base station may variously be referred to by those skilled in the art as a base transceiver station (BTS) , a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , an access point (AP) , a Node B (NB) , an eNode B (eNB) , a gNode B (gNB) , or some other suitable terminology.

The radio access network 104 is further illustrated supporting wireless communication for multiple mobile apparatuses. A mobile apparatus may be referred to as user equipment (UE) in 3GPP standards, but may also be referred to by those skilled in the art as a mobile station (MS) , 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 (AT) , a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. A UE may be an apparatus (e.g., a mobile apparatus) that provides a user with access to network services.

Within the present document, a “mobile” apparatus need not necessarily have a capability to move, and may be stationary. The term mobile apparatus or mobile device broadly refers to a diverse array of devices and technologies. UEs may include a number of hardware structural components sized, shaped, and arranged to help in communication; such components can include antennas, antenna arrays, RF chains, amplifiers, one or more processors, etc. electrically coupled to each other. For example, some non-limiting examples of a mobile apparatus include a mobile, a cellular (cell) phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal computer (PC) , a notebook, a netbook, a smartbook, a tablet, a personal digital assistant (PDA) , and a broad array of embedded systems, e.g., corresponding to an “Internet of things” (IoT) . A mobile apparatus may additionally be an automotive or other transportation vehicle, a remote sensor or actuator, a robot or robotics device, a satellite radio, a global positioning system (GPS) device, an object tracking device, a drone, a multi-copter, a quad-copter, a remote control device, a consumer and/or wearable device, such as eyewear, a wearable camera, a virtual reality device, a smart watch, a health or fitness tracker, a digital audio player (e.g., MP3 player) , a camera, a game console, etc. A mobile apparatus may additionally be a digital home or smart home device such as a home audio, video, and/or multimedia device, an appliance, a vending machine, intelligent lighting, a home security system, a smart meter, etc. A mobile apparatus may additionally be a smart energy device, a security device, a solar panel or solar array, a municipal infrastructure device controlling electric power (e.g., a smart grid) , lighting, water, etc.; an industrial automation and enterprise device; a logistics controller; agricultural equipment; military defense equipment, vehicles, aircraft, ships, and weaponry, etc. Still further, a mobile apparatus may provide for connected medicine or telemedicine support, e.g., health care at a distance. Telehealth devices may include telehealth monitoring devices and telehealth administration devices, whose communication may be given preferential treatment or prioritized access over other types of information, e.g., in terms of prioritized access for transport of critical service data, and/or relevant QoS for transport of critical service data.

Wireless communication between a RAN 104 and a UE 106 may be described as utilizing an air interface. Transmissions over the air interface from a base station (e.g., base station 108) to one or more UEs (e.g., UE 106) may be referred to as downlink (DL) transmission. In accordance with certain aspects of the present disclosure, the term downlink may refer to a point-to-multipoint transmission originating at a scheduling entity (described further below; e.g., base station 108) . Another way to describe this scheme may be to use the term broadcast channel multiplexing. Transmissions from a UE (e.g., UE 106) to a base station (e.g., base station 108) may be referred to as uplink (UL) transmissions. In accordance with further aspects of the present disclosure, the term uplink may refer to a point-to-point transmission originating at a scheduled entity (described further below; e.g., UE 106) .

In some examples, access to the air interface may be scheduled, wherein a scheduling entity (e.g., a base station 108) allocates resources for communication among some or all devices and equipment within its service area or cell. Within the present disclosure, as discussed further below, the scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more scheduled entities. That is, for scheduled communication, UEs 106, which may be scheduled entities, may utilize resources allocated by the scheduling entity 108.

Base stations 108 are not the only entities that may function as scheduling entities. That is, in some examples, a UE may function as a scheduling entity, scheduling resources for one or more scheduled entities (e.g., one or more other UEs) .

As illustrated in FIG. 1, a scheduling entity 108 may broadcast downlink traffic 112 to one or more scheduled entities 106. Broadly, the scheduling entity 108 is a node or device responsible for scheduling traffic in a wireless communication network, including the downlink traffic 112 and, in some examples, uplink traffic 116 from one or more scheduled entities 106 to the scheduling entity 108. On the other hand, the scheduled entity 106 is a node or device that receives downlink control information 114, including but not limited to scheduling information (e.g., a grant) , synchronization or timing information, or other control information from another entity in the wireless communication network such as the scheduling entity 108.

In general, base stations 108 may include a backhaul interface for communication with a backhaul portion 120 of the wireless communication system. The backhaul 120 may provide a link between a base station 108 and the core network 102. Further, in some examples, a backhaul network may provide interconnection between the respective base stations 108. Various types of backhaul interfaces may be employed, such as a direct physical connection, a virtual network, or the like using any suitable transport network.

The core network 102 may be a part of the wireless communication system 100, and may be independent of the radio access technology used in the RAN 104. In some examples, the core network 102 may be configured according to 5G standards (e.g., 5GC) . In other examples, the core network 102 may be configured according to a 4G evolved packet core (EPC) , or any other suitable standard or configuration.

Referring now to FIG. 2, by way of example and without limitation, a block diagram illustrating an example of various components of a 5G wireless communication system (5GS) 200 is provided. In some examples, the 5GS 200 may be the same wireless communication system 100 described above and illustrated in FIG. 1. The 5GS 200 includes a user equipment (UE) 202, a NR RAN 204, and a core network 206. By virtue of the wireless communication system 200, the UE 202 may be enabled to carry out data communication with an external data network 214, such as (but not limited to) the Internet, Ethernet network, an IP multimedia subsystem (IMS) network, or a local area network.

The core network 206 may include, for example, an access and mobility management function (AMF) 208, a session management function (SMF) 210, and a user plane function (UPF) 212. The AMF 208 and SMF 210 employ control plane (e.g., Non Access Stratum (NAS) ) signaling to perform various functions related to mobility management and session management for the UE 202. For example, the AMF 208 provides connectivity, mobility management and authentication of the UE 202, while the SMF 210 provides session management of the UE 202 (e.g., processes signaling related to protocol data unit (PDU) sessions between the UE 202 and the external DN 214) . The UPF 212 provides user plane connectivity to route 5G (NR) packets to/from the UE 202 via the NR RAN 204.

The core network 206 may further include other functions, such as a policy control function (PCF) 216, authentication server function (AUSF) 218, unified data management (UDM) 220, network slice selection function (NSSF) 222, and other functions (not illustrated, for simplicity) . The PCF 216 provides policy information (e.g., rules) for control plane functions, such as network slicing, roaming, and mobility management. In addition, the PCF 216 supports 5G quality of service (QoS) policies, network slice policies, and other types of policies. The AUSF 218 performs authentication of UEs 202. The UDM 220 facilitates generation of authentication and key agreement (AKA) credentials, performs user identification and manages subscription information and UE context. In some examples, the AMF 208 includes a co-located security anchor function (SEAF) that allows for re-authentication of a UE 202 when the UE moves between different NR RANs 204 without having to perform a complete authentication process with the AUSF 218. The NSSF 222 redirects traffic to a network slice. Network slices may be defined, for example, for different classes of subscribers or use cases, such as smart home, Internet of Things (IoT) , connected car, smart energy grid, etc. Each use case may receive a unique set of optimized resources and network topology (e.g., a network slice) to meet the connectivity, speed, power, and capacity requirements of the use case.

To establish a connection to the 5G core network 206 via the NR RAN 204, the UE 202 may transmit a registration request and PDU session establishment request to the 5G core network 206 via the NR RAN 204. The AMF 208 and SMF 210 may process the registration request and PDU session establishment request and establish a PDU session between the UE 202 and the external DN 214 via the UPF 212. A PDU session may include one or more sessions (e.g., data sessions or data flows) and may be served by multiple UPFs 212 (only one of which is shown for convenience) . Examples of data flows include, but are not limited to, IP flows, Ethernet flows and unstructured data flows.

Referring now to FIG. 3, by way of example and without limitation, a schematic illustration of a RAN 300 is provided. In some examples, the RAN 300 may be the same as the RAN 104 described above and illustrated in FIG. 1 and/or the NR RAN 204 described above and illustrated in FIG. 2. The geographic area covered by the RAN 300 may be divided into cellular regions (cells) that can be uniquely identified by a user equipment (UE) based on an identification broadcasted from one access point or base station. FIG. 3 illustrates

macrocells

302, 304, and 306, and a small cell 308, each of which may include one or more sectors (not shown) . A sector is a sub-area of a cell. All sectors within one cell are served by the same base station. A radio link within a sector can be identified by a single logical identification belonging to that sector. In a cell that is divided into sectors, the multiple sectors within a cell can be formed by groups of antennas with each antenna responsible for communication with UEs in a portion of the cell.

In FIG. 3, two base stations 310 and 312 are shown in

cells

302 and 304; and a third base station 314 is shown controlling a remote radio head (RRH) 316 in cell 306. That is, a base station can have an integrated antenna or can be connected to an antenna or RRH by feeder cables. In the illustrated example, the

cells

302, 304, and 126 may be referred to as macrocells, as the

base stations

310, 312, and 314 support cells having a large size. Further, a base station 318 is shown in the small cell 308 (e.g., a microcell, picocell, femtocell, home base station, home Node B, home eNode B, etc. ) which may overlap with one or more macrocells. In this example, the cell 308 may be referred to as a small cell, as the base station 318 supports a cell having a relatively small size. Cell sizing can be done according to system design as well as component constraints.

It is to be understood that the radio access network 300 may include any number of wireless base stations and cells. Further, a relay node may be deployed to extend the size or coverage area of a given cell. The

base stations

310, 312, 314, 318 provide wireless access points to a core network for any number of mobile apparatuses. In some examples, the

base stations

310, 312, 314, and/or 318 may be the same as the base station/scheduling entity 108 described above and illustrated in FIG. 1.

FIG. 3 further includes a quadcopter or drone 320, which may be configured to function as a base station. That is, in some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile base station such as the quadcopter 320.

Within the RAN 300, the cells may include UEs that may be in communication with one or more sectors of each cell. Further, each

base station

310, 312, 314, 318, and 320 may be configured to provide an access point to a core network 102 (see FIG. 1) for all the UEs in the respective cells. For example,

UEs

322 and 324 may be in communication with base station 310;

UEs

326 and 328 may be in communication with base station 312;

UEs

330 and 332 may be in communication with base station 314 by way of RRH 316; UE 334 may be in communication with base station 318; and UE 336 may be in communication with mobile base station 320. In some examples, the

UEs

322, 324, 326, 328, 330, 332, 334, 336, 338, 340, and/or 342 may be the same as the UE/scheduled entity 106 described above and illustrated in FIG. 1.

In some examples, a mobile network node (e.g., quadcopter 320) may be configured to function as a UE. For example, the quadcopter 320 may operate within cell 302 by communicating with base station 310.

In a further aspect of the RAN 300, sidelink signals may be used between UEs without necessarily relying on scheduling or control information from a base station. For example, two or more UEs (e.g., UEs 326 and 328) may communicate with each other using peer to peer (P2P) or sidelink signals 327 without relaying that communication through a base station (e.g., base station 312) . In a further example, UE 338 is illustrated communicating with

UEs

340 and 342. Here, the UE 338 may function as a scheduling entity or a primary sidelink device, and

UEs

340 and 342 may function as a scheduled entity or a non-primary (e.g., secondary) sidelink device. In still another example, a UE may function as a scheduling entity in a device-to-device (D2D) , peer-to-peer (P2P) , or vehicle-to-vehicle (V2V) network, and/or in a mesh network. In a mesh network example,

UEs

340 and 342 may optionally communicate directly with one another in addition to communicating with the scheduling entity 338. Thus, in a wireless communication system with scheduled access to time–frequency resources and having a cellular configuration, a P2P configuration, or a mesh configuration, a scheduling entity and one or more scheduled entities may communicate utilizing the scheduled resources.

In the radio access network 300, the ability for a UE to communicate while moving, independent of its location, is referred to as mobility. The various physical channels between the UE and the radio access network are generally set up, maintained, and released under the control of an access and mobility management function (AMF, not illustrated, part of the core network 102 in FIG. 1) , which may include a security context management function (SCMF) that manages the security context for both the control plane and the user plane functionality, and a security anchor function (SEAF) that performs authentication.

In various aspects of the disclosure, a radio access network 300 may utilize DL-based mobility or UL-based mobility to enable mobility and handovers (i.e., the transfer of a UE’s connection from one radio channel to another) . In a network configured for DL-based mobility, during a call with a scheduling entity, or at any other time, a UE may monitor various parameters of the signal from its serving cell as well as various parameters of neighboring cells. Depending on the quality of these parameters, the UE may maintain communication with one or more of the neighboring cells. During this time, if the UE moves from one cell to another, or if signal quality from a neighboring cell exceeds that from the serving cell for a given amount of time, the UE may undertake a handoff or handover from the serving cell to the neighboring (target) cell. For example, UE 324 (illustrated as a vehicle, although any suitable form of UE may be used) may move from the geographic area corresponding to its serving cell 302 to the geographic area corresponding to a neighbor cell 306. When the signal strength or quality from the neighbor cell 306 exceeds that of its serving cell 302 for a given amount of time, the UE 324 may transmit a reporting message to its serving base station 310 indicating this condition. In response, the UE 324 may receive a handover command, and the UE may undergo a handover to the cell 306.

In a network configured for UL-based mobility, UL reference signals from each UE may be utilized by the network to select a serving cell for each UE. In some examples, the

base stations

310, 312, and 314/216 may broadcast unified synchronization signals (e.g., unified Primary Synchronization Signals (PSSs) , unified Secondary Synchronization Signals (SSSs) and unified Physical Broadcast Channels (PBCH) ) . The

UEs

322, 324, 326, 328, 330, and 332 may receive the unified synchronization signals, derive the carrier frequency and slot timing from the synchronization signals, and in response to deriving timing, transmit an uplink pilot or reference signal. The uplink pilot signal transmitted by a UE (e.g., UE 324) may be concurrently received by two or more cells (e.g., base stations 310 and 314/216) within the radio access network 300. Each of the cells may measure a strength of the pilot signal, and the radio access network (e.g., one or more of the base stations 310 and 314/216 and/or a central node within the core network) may determine a serving cell for the UE 324. As the UE 324 moves through the radio access network 300, the network may continue to monitor the uplink pilot signal transmitted by the UE 324. When the signal strength or quality of the pilot signal measured by a neighboring cell exceeds that of the signal strength or quality measured by the serving cell, the network 300 may handover the UE 324 from the serving cell to the neighboring cell, with or without informing the UE 324.

Although the synchronization signal transmitted by the

base stations

310, 312, and 314/216 may be unified, the synchronization signal may not identify a particular cell, but rather may identify a zone of multiple cells operating on the same frequency and/or with the same timing. The use of zones in 5G networks or other next generation communication networks enables the uplink-based mobility framework and improves the efficiency of both the UE and the network, since the number of mobility messages that need to be exchanged between the UE and the network may be reduced.

The air interface in the radio access network 300 may utilize one or more duplexing algorithms. Duplex refers to a point-to-point communication link where both endpoints can communicate with one another in both directions. Full duplex means both endpoints can simultaneously communicate with one another. Half duplex means only one endpoint can send information to the other at a time. In a wireless link, a full duplex channel generally relies on physical isolation of a transmitter and receiver, and suitable interference cancellation technologies. Full duplex emulation is frequently implemented for wireless links by utilizing frequency division duplex (FDD) or time division duplex (TDD) . In FDD, transmissions in different directions operate at different carrier frequencies. In TDD, transmissions in different directions on a given channel are separated from one another using time division multiplexing. That is, at some times the channel is dedicated for transmissions in one direction, while at other times the channel is dedicated for transmissions in the other direction, where the direction may change very rapidly, e.g., several times per slot.

In some aspects of the disclosure, the scheduling entity and/or scheduled entity may be configured for beamforming and/or multiple-input multiple-output (MIMO) technology. FIG. 4 illustrates an example of a wireless communication system 400 supporting MIMO. In a MIMO system, a transmitter 402 includes multiple transmit antennas 404 (e.g., N transmit antennas) and a receiver 406 includes multiple receive antennas 408 (e.g., M receive antennas) . Thus, there are N × M signal paths 410 from the transmit antennas 404 to the receive antennas 408. Each of the transmitter 402 and the receiver 406 may be implemented, for example, within a scheduling entity 108, a scheduled entity 106, or any other suitable wireless communication device.

The use of such multiple antenna technology enables the wireless communication system to exploit the spatial domain to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing may be used to transmit different streams of data, also referred to as layers, simultaneously on the same time-frequency resource. The data streams may be transmitted to a single UE to increase the data rate or to multiple UEs to increase the overall system capacity, the latter being referred to as multi-user MIMO (MU-MIMO) . This is achieved by spatially precoding each data stream (i.e., multiplying the data streams with different weighting and phase shifting) and then transmitting each spatially precoded stream through multiple transmit antennas on the downlink. The spatially precoded data streams arrive at the UE (s) with different spatial signatures, which enables each of the UE (s) to recover the one or more data streams destined for that UE. On the uplink, each UE transmits a spatially precoded data stream, which enables the base station to identify the source of each spatially precoded data stream.

The number of data streams or layers corresponds to the rank of the transmission. In general, the rank of the MIMO system 400 is limited by the number of transmit or receive

antennas

404 or 408, whichever is lower. In addition, the channel conditions at the UE, as well as other considerations, such as the available resources at the base station, may also affect the transmission rank. For example, the rank (and therefore, the number of data streams) assigned to a particular UE on the downlink may be determined based on the rank indicator (RI) transmitted from the UE to the base station. The RI may be determined based on the antenna configuration (e.g., the number of transmit and receive antennas) and a measured signal-to-interference-and-noise ratio (SINR) on each of the receive antennas. The RI may indicate, for example, the number of layers that may be supported under the current channel conditions. The base station may use the RI, along with resource information (e.g., the available resources and amount of data to be scheduled for the UE) , to assign a transmission rank to the UE.

In Time Division Duplex (TDD) systems, the UL and DL are reciprocal, in that each uses different time slots of the same frequency bandwidth. Therefore, in TDD systems, the base station may assign the rank for DL MIMO transmissions based on UL SINR measurements (e.g., based on a Sounding Reference Signal (SRS) transmitted from the UE or other pilot signal) . Based on the assigned rank, the base station may then transmit the CSI-RS with separate C-RS sequences for each layer to provide for multi-layer channel estimation. From the CSI-RS, the UE may measure the channel quality across layers and resource blocks and feed back the CQI and RI values to the base station for use in updating the rank and assigning REs for future downlink transmissions.

In the simplest case, as shown in FIG. 4, a rank-2 spatial multiplexing transmission on a 2x2 MIMO antenna configuration will transmit one data stream from each transmit antenna 404. Each data stream reaches each receive antenna 408 along a different signal path 410. The receiver 406 may then reconstruct the data streams using the received signals from each receive antenna 408.

In order to access a service provided by a service network, a UE may perform a service registration with the service network. In an example, when the UE access the service via an NR base station operating an NR RAN, the service registration may be performed after an NR standalone (SA) attach process is successfully performed. The service network may be an IMS network and the service registration may be an IMS registration. The service registration may be performed using a session initiation protocol (SIP) process. In some instances, the service registration may fail due to reasons associated with a network or due to reasons associated with the UE itself. If the service registration fails due to reasons associated with a network, such as limitations or errors in the network, the network may send a forbidden response (e.g., SIP 403 forbidden response) , which may cause the UE to avoid retrying the service registration with such a network. For example, if the forbidden response is received while attempting to register via a network, the forbidden response may lead to a permanent failure of the service registration via the network. In such an example, when the forbidden response is received, the UE may disable a mode (e.g., N1 mode) that allows the UE to access a core network via an NR RAN.

In an aspect, if the UE receives a forbidden response during a service registration via a base station associated with a cell, the UE may retry a service registration via a different base station associated with a different cell. One example of retrying a service registration in a case where a forbidden response is received is explained in PCT Application No. PCT/CN2020/091721.

FIG. 5 is an example diagram 500 illustrating an example of retrying a service registration process after an unsuccessful service registration. The example diagram 500 of FIG. 5 involves communication among a UE 502, a first NR base station 504 operating in a first NR cell associated with a first tracking area code (TAC) , a second NR base station 506 operating in a second NR cell associated with a second TAC. In an aspect, the first NR base station 504 and the second NR base station 506 may operate within the same NR RAN.

The first NR base station 504 and the second NR base station 506 may be connected to a service network (e.g., an IMS network) via a core network. At 522, as an attachment process to the first NR base station 504, the UE 502 transmits a registration request to the first NR base station 504. At 524, the first NR`base station 504 accepts the registration request and sends a registration accept message to the UE 502 to indicate that the registration request has been accepted. At 526, the UE 502 initiates a process to establish a first PDU session with the service network (e.g., for voice or data service) by transmitting a PDU session establishment request to the first NR base station 504. In response, the first NR base station 504 communicates with the service network to establish the first PDU session for the UE 502. At 528, when the first PDU session is established, the first NR base station 504 sends a PDU session establishment message to the UE 502 to indicate that the first PDU session has been established.

Subsequently, the UE 502 performs a service registration (e.g., IMS registration) with the service network via the first NR base station 504, which may be performed via SIP messages. At 530, the UE 502 performs the service registration by transmitting a service register message (e.g., SIP register message) to the first NR base station 504. In response, the first NR base station 504 may communicate with the service network to perform the service registration for the UE 502. If the service registration fails due to network reasons, then the first NR base station 504 transmits a service register forbidden message (e.g., 403 Forbidden message) to the UE 502, to indicate that the service is forbidden.

When the UE 502 receives the service register forbidden message, the UE 502 may perform a cell reselection to the second NR cell operated by the second NR base station 506. In an aspect, in response to the service register forbidden message, the UE 502 may add a first TAC associated with the first NR base station 504 to a forbidden TAC list, to remove the first NR base station 504 from consideration. When the cell reselection is initiated, at 542, as an attachment process to the second NR base station 506, the UE 502 transmits a registration request to the second NR base station 506. At 544, the second NR base station 506 accepts the registration request and thus sends a registration accept message to the UE 502. At 546, the UE 502 sends a PDU session establishment request to the second NR base station 506 to establish a second PDU session with the service network. In response, the second NR base station 506 communicates with the service network to establish the second PDU session for the UE 502. At 528, when the second PDU session is established, the second NR base station 506 sends a PDU session establishment message to the UE 502 to indicate that the second PDU session has been established.

Subsequently, the UE 502 performs a service registration (e.g., IMS registration) with the service network via the second NR base station 506, which may be performed via SIP messages. At 550, the UE 502 performs the service registration by transmitting a service register message (e.g., SIP register message) to the second NR base station 506. In response, the second NR base station 506 may communicate with the service network to perform the service registration for the UE 502. If the service registration is accepted, then the second NR base station 506 transmits a service register accept message (e.g., 200 OK message) to the UE 502, to indicate that the service registration has been accepted. This allows the UE to be able to provide a service (e.g., data communication) via the second NR base station 506, without a handover to an LTE network node.

A UE may communicate with a service network using a subscription for a service (e.g., data service, voice service) provided by the service network. The UE may implement a subscription module such as a subscriber identification module (SIM) to connect to the service network. A UE may be configured to communicate using two or more subscriptions. For example, a UE implementing multiple SIMs respectively associated with multiple subscriptions may communicate using the multiple subscriptions via the multiple SIMs, according to, for example, dual SIM, dual standby (DSDS) or dual SIM, dual active (DSDA) . For a UE configured to communicate using multiple subscriptions, the UE may initially use a first subscription of the multiple subscriptions to perform a service registration with a service network via a first NR base station associated with a first tracking area. If the UE fails to successfully perform the service registration using the first subscription via the first NR base station, the UE may reselect to a second NR base station to perform a service registration with the service network via the second NR base station. The UE may determine that the UE has failed to successfully perform the service registration if the UE receives a service forbidden message in response to sending a service register message.

However, even after determining that the UE has failed to successfully perform the service registration using the first subscription via the first NR base station, the UE may still perform a service registration using a second subscription via the first NR base station. In such a case, the service registration using the second subscription via the first NR base station is likely to fail as well, which may trigger reselection to the second NR base station for the service registration using the second subscription. Hence, the UE may end up wasting time, power, processing resources, and/or signaling resources trying to use the second subscription with the first base station that is likely to cause a service registration failure. If the service registration using the second subscription with the first base station fails, reselecting to another base station using the second subscription and attempting to perform another service registration may cause additional delays and adversely affect user experience. Such adverse results may occur even when the UE is aware of the service registration failure using the first subscription with the first base station and both the first and second subscriptions are used by the same UE. Therefore, improvements to the UE configured to communicate using multiple subscriptions are desired to minimize or eliminate such adverse effects in case of a service registration failure with an NR base station using one subscription.

According to an aspect of the disclosure, when a UE camped on a first network node (e.g., first base station) determines that a service registration using a first subscription via the first network node associated with a first tracking area has failed, the UE performs a cell reselection to a second network node (e.g., second base station) associated with a second tracking area and performs a service registration using a second subscription via the second network node, where the second network node is associated with a second tracking area different from the first tracking area of the first network node. For example, the UE may determine that the service registration using the first subscription via the first network node has failed when the UE receives a forbidden response such as a SIP 403 Forbidden response. In an aspect, the UE may be in an NR standalone mode, which may allow 5G NR communication without an LTE network, and the first and second network nodes may be NR network nodes (e.g., NR base stations such as gNBs) . The UE is configured to communicate using multiple subscriptions, such as the first subscription and the second subscription. In an aspect, the UE may implement multiple subscription modules via which the multiple subscriptions are used for communication, respectively. The multiple subscription modules may be separate modules or may be implemented as a single integrated module. For example, the multiple subscription modules may be multiple SIMs or may be implemented in a single SIM. In an aspect, when the service registration using a first subscription via the first network node fails, the UE may trigger a PLMN search (e.g., via the second subscription module) as a part of the cell reselection process to find a network node associated with a tracking area different from the tracking area of the first network node, and may find the second network node as a suitable network node for the cell reselection by the UE.

In an aspect, when the service registration using a first subscription via the first network node fails, the UE may avoid selecting the first network node for service registration using the second subscription. In an aspect, in response to such a service registration failure via a currently serving network node, which is the first network node in this description, the UE may add a TAC of the currently serving network node to a forbidden TAC list. In an aspect, adding the TAC of the currently serving network node to the forbidden TAC list may be triggered and/or performed by a first subscription module of the UE, where the first subscription is used via the first subscription module. In the above description, the currently serving network node is the first network node when the service registration using the first subscription fails, and thus the UE may add a first TAC of the first network node to the forbidden TAC list. In an aspect, the forbidden TAC list may be conveyed to a second subscription module of the UE and/or to the second subscription. The forbidden TAC list may be used to indicate that the UE should trigger and/or perform a cell reselection to a new network node associated with a new TAC different from the first TAC, so as to avoid a service registration failure similar to the service registration failure via the first network node associated with the first TAC. For example, the forbidden TAC list may list one or more tracking area codes such that the UE may avoid utilizing network nodes associated with the listed tracking area codes for service registration. For example, based on the forbidden TAC list, the UE may trigger and/or perform a cell reselection via the first subscription module and/or the second subscription module.

After the UE performs the cell reselection to the second network node and camps on the second network node, the UE may perform a service registration (e.g., via the second subscription module) using the second subscription via the second network node. If the service registration using the second subscription via the second network node is successful, the UE may perform data communication based on this service registration using the second subscription via the second network node. Therefore, if the UE determines that a service registration attempt using a first subscription via a particular base station has failed, the UE does not waste time attempting to use a second subscription for service registration via this particular base station but rather looks for another base station for service registration using the second subscription. As such, this feature may save time, power, processing resources, and signaling resources for the UE and possibly the second subscription module. Further, this allows avoiding an unnecessary service registration failure using the second subscription via this particular base station, which eliminates or reduces a delay associated with a service registration failure.

FIG. 6 is an example diagram 600 illustrating communications between a user equipment configured to communicate using multiple subscriptions and various network nodes to perform a service registration, according to an aspect of the disclosure. In the example diagram 600, a UE 602 may be configured to communicate using a first subscription and a second subscription. In an aspect, the UE 602 may include a first subscription module 604 via which the UE 602 may use the first subscription for communication and a second subscription module 606 via which the UE 602 may use the second subscription for communication. In an aspect, the first subscription module 604 and second subscription module 606 may be implemented as a single module or may be implemented as two separate modules. In an aspect, the first subscription module 604 and second subscription module 606 may be a part of the UE 602, or may be separate devices such as SIM cards that can be inserted in to the UE 602. The UE 602 may perform a service registration via a network node such as a base station, where the network node is associated with a tracking area code that indicates a particular tracking area corresponding to the network node. In the example diagram 600, a first network node 612 operating in a first cell 622, a second network node 614 operating in a second cell 624, and a third network node 616 operating in a third cell 626 are available for communication with the UE 602. The first network node 612, the second network node 614, and the third network node 616 are associated with a first tracking area code TAC1, a second tracking area code TAC2, and a third tracking area code TAC3, respectively. In an aspect, the first network node 612, the second network node 614, and the third network node 616 may utilize the same RAT, which may be based on 5G NR technology.

When the UE 602 camps on the first cell 622 by an attachment procedure with the first network node 612 and establishes a first PDU session via the first network node 612, the UE 602 may perform a first service registration using the first subscription (e.g., via the first subscription module 604) to register with a first service network 642 via the first network node 612, and for example, via a first core network 632 connected to the first service network 642. If the first service registration using the first subscription via the first network node 612 fails, the UE 602 triggers a cell reselection to another network node associated with a different tracking area code such as the second network node 614, using the second subscription (e.g., via the second subscription module 606) , to register with a service network via the second network node 614. In an aspect, the UE 602 may perform a new cell search (e.g., PLMN search) if the first service registration using the first subscription fails, and the UE 602 may trigger the reselection to another cell found by the new cell search. In the example diagram 600, the new cell search may find that the second network node 614 is a suitable network node for the UE 602.

In an aspect, if the first service registration using the first subscription via the first network node 612 fails, prior to triggering the cell reselection using the second subscription, the UE 602 may select a network node for the cell reselection among multiple network nodes available for the cell reselection based on priority values respectively associated with the multiple network nodes. For example, if the first service registration using the first subscription via the first network node 612 fails, the UE 602 may select the second network node 614 among multiple network nodes available for the cell reselection based on priority values respectively associated with the multiple network nodes. In this example, the second network node 614 may be associated with the highest priority value among the priority values associated with the multiple network nodes. After selecting the second network node 614 among the multiple network nodes, the 602 may trigger the cell reselection to the second network node 614 using the second subscription. In such an aspect, the priority values may be based on signal strength values respectively associated with the multiple network nodes. Further, in such an aspect, the multiple network nodes may be found by the new cell search (e.g., PLMN search) performed in response to determining that the first service registration using the first subscription has failed.

In an aspect, if the first service registration using the first subscription via the first network node 612 fails, the UE 602 may trigger a cell reselection to another network node associated with a different tracking area code such as the second network node 614, using the first subscription (e.g., via the first subscription module 604) , to register with a service network via the second network node 614. In this aspect, after the cell reselection to the second network node 614 using the first subscription, the UE 602 may perform a subsequent service registration using the first subscription to register with the first service network 642 (e.g., through the first core network 632) or a different service network such as a second service network 644 (e.g., through a second core network 634) via the second network node 614. In an aspect, triggering of the cell reselection to the second network node using the second subscription may be performed if the UE 602 determines that performing the subsequent service registration using the first subscription is successful. In an example, the first subscription module 604 may cause the UE 602 to send an indication to the second subscription module 606 that the subsequent service registration using the first subscription is successful, which triggers the cell reselection using the second subscription. Further, in an aspect, if the UE 602 determines that performing the subsequent service registration using the first subscription has failed, the UE 602 may trigger a cell reselection to the third network node 616 using the second subscription (e.g., via the second subscription module 606) , and may also trigger a cell reselection to the third network node 616 using the first subscription (e.g., via the first subscription module 604) . Hence, the UE 602 may continue trying to register using a new network node with a different tracking area code until a successful service registration is achieved, using the first subscription and/or the second subscription.

After the reselection to the second network node 614 using the second subscription, the UE 602 performs a second service registration using the second subscription (e.g., via the second subscription module 606) to register with the first service network 642 or a different service network such as the second service network 644 via the second network node 614. In an aspect, the first service network 642 and/or the second service network 644 may be IMS networks. In an aspect, prior to the second service registration, the UE 602 may establish a second PDU session with the second network node using the second subscription in response to triggering the cell reselection to the second network using the second subscription, such that the UE 602 may perform the second service registration using the second PDU session. If the second service registration using the second subscription is successful, the UE 602 may perform data communication based on the second service registration using the second subscription (e.g., via the second subscription module 606) .

In an aspect, if the subsequent service registration using the first subscription via the second network node 614 is successfully performed to register with a network (e.g., the first service network 642 or a different service network such as the second service network 644) , the UE 602 may perform the second service registration using the second subscription to register with the same network. For example, if the UE 602 successfully performs the subsequent service registration using the first subscription to register with the first service network 642 via the second network node 614, the UE 602 may reselect to the second network node 614 and perform the second service registration using the second subscription to register with the first service network 642 via the second network node 614. Similarly, in another example, if the UE 602 successfully performs the subsequent service registration using the first subscription to register with the second service network 644 via the second network node 614, the UE 602 may reselect to via the second network node 614 and perform the second service registration using the second subscription to register with the second service network 644 via the second network node 614.

In an aspect, if the UE 602 determines that the second service registration using the second subscription has failed, the UE 602 may trigger a cell reselection to a third network node using the first subscription in response to determining that the second service registration has failed, and subsequently may perform a third service registration using the first subscription to register with the service network via the third network node. If the third service registration using the second subscription is successful, the UE 602 may perform data communication based on the third service registration using the second subscription (e.g., via the second subscription module 606) .

In an aspect, if the first service registration using the first subscription via the first network node 612 fails, the UE 602 may prevent the UE 602 from selecting the first network node 612 for service registration using the second subscription. In an aspect, if the first service registration using the first subscription via the first network node 612 fails, the UE 602 may generate or update a forbidden tracking area list by adding the first tracking area code associated with the first network node 612 to the forbidden tracking area list. In this aspect, triggering of the cell reselection to the second network node 614 using the second subscription may be performed based on the forbidden tracking area list, e.g., by preventing a cell reselection to a network node associated with a tracking area code listed on the forbidden tracking area. In this aspect, the UE 602 may provide the forbidden tracking area list to the second subscription, wherein the cell reselection to the second network node 614 using the second subscription is triggered in response to the forbidden tracking area list provided to the second subscription. In one example, the first subscription module 604 of the UE 602 may generate or update the forbidden tracking area list, and may share the forbidden tracking area list with the second subscription module 606 of the UE 602, such that the UE 602 may trigger via the second subscription module 606 a cell reselection using the second subscription to a network node associated with a tracking area code different from a tracking area of a network node code listed in the forbidden tracking area list. Further, in an aspect, the UE may trigger via the first subscription module 604 a cell reselection using the first subscription to a network node associated with a tracking area code different from a tracking area of a network node code listed in the forbidden tracking area list.

FIG. 7 is an example diagram 700 illustrating a process for service registration with a user equipment configured to communicate using multiple subscriptions, according to an aspect of the disclosure. The example diagram 700 of FIG. 7 involves communication among a UE 702, a first NR base station 712 operating in a first NR cell associated with a first tracking area code TAC1, a second NR base station 714 operating in a second NR cell associated with a second tracking area code TAC2. In an aspect, the first NR base station 712 and the second NR base station 714 may operate within the same NR RAN. The UE 702 is configured to communicate using two subscriptions. In particular, the UE 702 may communicate using a first subscription via a first subscription module 704 and may communicate using a second subscription via a second subscription module 706.

At 722, the UE 702 successfully performs an attachment process to the first NR base station 712 via the first subscription module 704 by registering with the first NR base station 712. At 724, the UE 702 initiates a process to establish a first PDU session with a service network (not shown) such as an IMS network via the first subscription module 704 by transmitting a PDU session establishment request to the first NR base station 712, which then communicates with the service network to establish the first PDU session for the UE 702. At 726, when the first PDU session is established, the first NR base station 712 sends a PDU session establishment message to the UE 702 to indicate that the first PDU session has been established, and the UE 702 receives the PDU session establishment message via the first subscription module 704. Subsequently, at 728, the UE 702 performs a first service registration (e.g., IMS registration) with the service network by transmitting a service register message (e.g., SIP register message) to the first NR base station 712 via the first subscription module 704. In response, the first NR base station 712 may communicate with the service network to perform the service registration for the UE 702. If the first service registration fails due to network reasons, then the first NR base station 712 transmits a service register forbidden message (e.g., 403 Forbidden message) to the UE 702, to indicate that the service is forbidden.

When the UE 702 receives the service register forbidden message (e.g., via the first subscription module 704) , the UE 702 may determine that the first service registration has failed. In response to determining that the first service registration has failed, at 732, the UE 702 may trigger a cell reselection to the second NR base station 714 using the first subscription via the first subscription module 704, so as to attempt a subsequent service registration using the first subscription via the second NR base station 714.

Further, in response to determining that the first service registration has failed, the UE 702 may add the first tracking area associated with the first NR base station 712 to a forbidden tracking area list (e.g., via the first subscription module 704) . At 734, the UE 702 may convey the forbidden tracking area list to the second subscription module 706 via the first subscription module 704. Based on the forbidden tracking area list, at 736, the UE 702 triggers a cell reselection to the second NR base station 714 using the second subscription via the second subscription module 706. In response to triggering the cell reselection using the second subscription, at 738, the UE 702 transmits a registration request to the second NR base station 714 to attach to the second NR base station 714. If the second NR base station 714 accepts the registration, at 740, the second NR base station 714 sends the registration accept message to the UE 702.

When the UE 702 receives the registration accept message via the second subscription module 706, at 741, the UE 702 sends a PDU session establishment request to the second NR base station 714 using the second subscription via the second subscription module 706 to establish a second PDU session with the service network. In response, the second NR base station 714 communicates with the service network to establish the second PDU session for the UE 702. At 744, when the second PDU session is established, the second NR base station 714 sends a PDU session establishment message to the UE 702 to indicate that the second PDU session has been established.

When the UE 702 receives the PDU session establishment message via the second subscription module 706, the UE 702 performs a second service registration (e.g., IMS registration) with the service network via the second NR base station 714, which may be performed via SIP messages. At 746, the UE 502 performs the second service registration by transmitting a service register message (e.g., SIP register message) to the second NR base station 714 using the second subscription via the second subscription module 706. In response, the second NR base station 714 may communicate with the service network to perform the second service registration for the UE 702. If the second service registration is accepted, then the second NR base station 714 transmits a service register accept message (e.g., 200 OK message) to the UE 702, to indicate that the second service registration has been accepted. Once the UE 702 receives the service register accept message, the UE 702 may perform data communication based on the second service registration using the second subscription via the second subscription module 706 and the second NR base station 714.

FIG. 8 is a block diagram illustrating an example of a hardware implementation for a UE 800 employing a processing system 814. For example, the UE 800 may be a UE as illustrated in any one or more of FIGs. 1, 2, 3, 4, 6, and/or 7.8

The UE 800 may be implemented with a processing system 814 that includes one or more processors 804. Examples of processors 804 include microprocessors, microcontrollers, digital signal processors (DSPs) , 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. In various examples, the UE800 may be configured to perform any one or more of the functions described herein. That is, the processor 804, as utilized in a UE800, may be used to implement any one or more of the processes and procedures described below and illustrated in FIG. 9.

In this example, the processing system 814 may be implemented with a bus architecture, represented generally by the bus 802. The bus 802 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 814 and the overall design constraints. The bus 802 communicatively couples together various circuits including one or more processors (represented generally by the processor 804) , a memory 805, and computer-readable media (represented generally by the computer-readable medium 806) . The bus 802 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further. A bus interface 808 provides an interface between the bus 802 and a transceiver 810. The transceiver 810 provides a communication interface or means for communicating with various other apparatus over a transmission medium. In an aspect, the UE 800 may include a subscription module 816 that may be used to register with a service network. In such an aspect, the bus interface 808 may provide an interface between the bus 802, the transceiver 810, and the subscription module 816. In an aspect, the subscription module 816 may enable the UE 800 to use multiple subscriptions, such as a first subscription and a second subscription, to provide a service. The subscription module 816 may include multiple subscription modules respectively for the multiple subscriptions. Depending upon the nature of the apparatus, a user interface 812 (e.g., keypad, display, speaker, microphone, joystick) may also be provided. Of course, such a user interface 812 is optional, and may be omitted in some examples, such as a base station.

In some aspects of the disclosure, the processor 804 may include a service registration circuit 840 configured for various functions, including, for example, performing a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area. The service registration circuit 840 may further serve to determine that the first service registration using the first subscription has failed. For example, the service registration circuit 840 may be configured to implement one or more of the functions described below in relation to FIG. 9, including, e.g., block 902 and block 904. The cell reselection circuit 842 may serve to trigger a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, the second network node being associated with a second tracking area different from the first tracking area. For example, the cell reselection circuit 842 may be configured to implement one or more of the functions described below in relation to FIG. 9, including, e.g., block 908. The service registration circuit 840 may further serve to perform a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription. For example, the service registration circuit 840 may be configured to implement one or more of the functions described below in relation to FIG. 9, including, e.g., block 910.

The processor 804 is responsible for managing the bus 802 and general processing, including the execution of software stored on the computer-readable medium 806. The software, when executed by the processor 804, causes the processing system 814 to perform the various functions described below for any particular apparatus. The computer-readable medium 806 and the memory 805 may also be used for storing data that is manipulated by the processor 804 when executing software.

One or more processors 804 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 modules, 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. The software may reside on a computer-readable medium 806. The computer-readable medium 806 may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip) , an optical disk (e.g., a compact disc (CD) or a digital versatile disc (DVD) ) , a smart card, a flash memory device (e.g., a card, a stick, or a key drive) , a random access memory (RAM) , a read only memory (ROM) , a programmable ROM (PROM) , an erasable PROM (EPROM) , an electrically erasable PROM (EEPROM) , a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The computer-readable medium 806 may reside in the processing system 814, external to the processing system 814, or distributed across multiple entities including the processing system 814. The computer-readable medium 806 may be embodied in a computer program product. By way of example, a computer program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

In one or more examples, the computer-readable medium 806 may include service registration software or instructions 850 configured for various functions, including, for example, performing a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area. The service registration software or instructions 850 may further serve to determine that the first service registration using the first subscription has failed. For example, the service registration software or instructions 850 may be configured to implement one or more of the functions described below in relation to FIG. 9, including, e.g., block 902 and block 904. The cell reselection software or instructions 852 may serve to trigger a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, the second network node being associated with a second tracking area different from the first tracking area. For example, the cell reselection software or instructions 852 may be configured to implement one or more of the functions described below in relation to FIG. 9, including, e.g., block 908. The service registration software or instructions 850 may further serve to perform a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription. For example, the service registration software or instructions 850 may be configured to implement one or more of the functions described below in relation to FIG. 9, including, e.g., block 910. Of course, in the above examples, the circuitry included in the processor 804 is merely provided as an example, and other means for carrying out the described functions may be included within various aspects of the present disclosure, including but not limited to the instructions stored in the computer-readable medium 806, or any other suitable apparatus or means described in any one of the FIGs. 1, 2, 3, 4, 6, and/or 7, and utilizing, for example, the processes and/or algorithms described herein in relation to FIG. 9.

FIG. 9 is a flow chart illustrating an exemplary process 900 for wireless communication by a UE configured to communicate using multiple subscriptions, in accordance with some aspects of the present disclosure. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, the process 900 may be carried out by the UE 800 illustrated in FIG. 8. In some examples, the process 900 may be carried out by any suitable apparatus or means for carrying out the functions or algorithm described below.

At block 902, the process 900 includes performing a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area. In an aspect, the first service registration may be performed using a first packet session established with the first network node using the first subscription. At block 904, the process 900 includes determining whether the first service registration using the first subscription has failed. At block 906, if the UE determines that the first service registration using the first subscription has not failed, the UE may perform data communication based on the first service registration using the first subscription, via the first network node.

At block 908, if the UE determines that the first service registration using the first subscription has failed, the process 900 includes triggering a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, where the second network node is associated with a second tracking area different from the first tracking area. In an aspect, the process 900 may further include preventing the UE from selecting the first network node for service registration using the second subscription in response to determining that the first service registration has failed. In an aspect, the RAT of the first network node may be the same as a RAT of the second network node. In such an aspect, the RAT of the first network node and the RAT of the second network node may be based on 5G NR technology, and the first and second network nodes may be gNBs.

In an aspect, the process 900 may further include performing a cell search for a network node associated with a tracking area different from the first tracking area in response to determining that the first service registration has failed, where the cell reselection to the second network node is triggered at block 908 when the cell search finds the second network node. In an aspect, the process 900 may further include selecting the second network node among a plurality of network nodes based on priority values respectively associated with the plurality of network nodes and in response to determining that the first service registration has failed, where the cell reselection to the second network node using the second subscription is triggered at block 908 subsequent to selecting the second network node. In such an aspect, the priority values may be based on signal strength values respectively associated with the plurality of network nodes.

In an aspect, the process 900 may further include generating or updating a forbidden tracking area list by adding the first tracking area associated with the first network node to the forbidden tracking area list in response to determining that the first registration with the first network node has failed, where the cell reselection to the second network node using the second subscription may be triggered based on the forbidden tracking area list. In such an aspect, triggering the cell reselection to the second network node using the second subscription at block 908 may include providing the forbidden tracking area list to the second subscription, wherein the cell reselection to the second network node using the second subscription is triggered in response to the forbidden tracking area list provided to the second subscription.

In an aspect, the process 900 may further include triggering a cell reselection to the second network node using the first subscription in response to determining that the first service registration has failed, performing a subsequent service registration using the first subscription to register with the service network or the different service network via the second network node in response to triggering the cell reselection to the second network node using the first subscription, and determining whether the subsequent service registration is successful. In this aspect, the cell reselection to the second network node using the second subscription may be triggered at block 908 in response to determining that the first service registration has failed and that the subsequent service registration is successful. In such an aspect, the process 900 may further include determining that the subsequent service registration has failed, and determining that the subsequent service registration has failed.

In an aspect, the process 900 may further include determining that the second service registration has failed, triggering a cell reselection to a third network node using the first subscription in response to determining that the second service registration has failed, the third network node being associated with a third tracking area different from the first and second tracking areas, and performing a third service registration using the first subscription to register with the service network via the third network node in response to triggering the cell reselection to the third network node using the first subscription.

At block 910, the process 900 further includes performing a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription. Prior to block 910, the process 900 may further include establishing a second packet session with the second network node using the second subscription in response to triggering the cell reselection to the second network using the second subscription, wherein the second service registration is performed using the second packet session. At block 912, the process 900 may further include performing data communication based on the second service registration using the second subscription subsequent to performing the second service registration.

In one configuration, the UE 800 includes means for performing a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area; means for determining that the first service registration using the first subscription has failed; means for triggering a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, the second network node being associated with a second tracking area different from the first tracking area; and means for performing a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription. In one aspect, the aforementioned means may be the processor (s) 804 shown in FIG. 8 configured to perform the functions recited by the aforementioned means. In another aspect, the aforementioned means may be a circuit or any apparatus configured to perform the functions recited by the aforementioned means.

Of course, in the above examples, the circuitry included in the processor 804 is merely provided as an example, and other means for carrying out the described functions may be included within various aspects of the present disclosure, including but not limited to the instructions stored in the computer-readable medium 806, or any other suitable apparatus or means described in any one of the FIGs. 1, 2, 3, 4, 6, and/or 7, and utilizing, for example, the processes and/or algorithms described herein in relation to FIG. 9.

Several aspects of a wireless communication network have been presented with reference to an exemplary implementation. As those skilled in the art will readily appreciate, various aspects described throughout this disclosure may be extended to other telecommunication systems, network architectures and communication standards.

By way of example, various aspects may be implemented within other systems defined by 3GPP, such as Long-Term Evolution (LTE) , the Evolved Packet System (EPS) , the Universal Mobile Telecommunication System (UMTS) , and/or the Global System for Mobile (GSM) . Various aspects may also be extended to systems defined by the 3rd Generation Partnership Project 2 (3GPP2) , such as CDMA2000 and/or Evolution-Data Optimized (EV-DO) . Other examples may be implemented within systems employing IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Ultra-Wideband (UWB) , Bluetooth, and/or other suitable systems. The actual telecommunication standard, network architecture, and/or communication standard employed will depend on the specific application and the overall design constraints imposed on the system.

Within the present disclosure, the word “exemplary” is used to mean “serving as an example, instance, or illustration. ” Any implementation or aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects of the disclosure. Likewise, the term “aspects” does not require that all aspects of the disclosure include the discussed feature, advantage or mode of operation. The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B, and object B touches object C, then objects A and C may still be considered coupled to one another-even if they do not directly physically touch each other. For instance, a first object may be coupled to a second object even though the first object is never directly physically in contact with the second object. The terms “circuit” and “circuitry” are used broadly, and intended to include both hardware implementations of electrical devices and conductors that, when connected and configured, enable the performance of the functions described in the present disclosure, without limitation as to the type of electronic circuits, as well as software implementations of information and instructions that, when executed by a processor, enable the performance of the functions described in the present disclosure.

One or more of the components, steps, features and/or functions illustrated in FIGs. 1–9 may be rearranged and/or combined into a single component, step, feature or function or embodied in several components, steps, or functions. Additional elements, components, steps, and/or functions may also be added without departing from novel features disclosed herein. The apparatus, devices, and/or components illustrated in FIGs. 1–9 may be configured to perform one or more of the methods, features, or steps described herein. The novel algorithms described herein may also be efficiently implemented in software and/or embedded in hardware.

It is to be understood that the specific order or hierarchy of steps in the methods disclosed is an illustration of exemplary processes. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the methods may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented unless specifically recited therein.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” Unless specifically stated otherwise, the term “some” refers to one or more. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, b and c. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.

Claims

A method of wireless communication by a user equipment (UE) configured to communicate using multiple subscriptions, comprising:

performing a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area;

determining that the first service registration using the first subscription has failed;

triggering a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, the second network node being associated with a second tracking area different from the first tracking area; and

performing a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription.
The method of claim 1, further comprising:

performing data communication based on the second service registration using the second subscription subsequent to performing the second service registration.
The method of claim 1, wherein the first service registration is performed using a first packet session established with the first network node using the first subscription, and wherein the method further comprises:

establishing a second packet session with the second network node using the second subscription in response to triggering the cell reselection to the second network using the second subscription, wherein the second service registration is performed using the second packet session.
The method of claim 1, further comprising:

preventing the UE from selecting the first network node for service registration using the second subscription in response to determining that the first service registration has failed.
The method of claim 1, further comprising:

generating or updating a forbidden tracking area list by adding the first tracking area associated with the first network node to the forbidden tracking area list in response to determining that the first registration with the first network node has failed,

wherein the cell reselection to the second network node using the second subscription is triggered based on the forbidden tracking area list.
The method of claim 5, wherein triggering the cell reselection to the second network node using the second subscription comprises:

providing the forbidden tracking area list to the second subscription, wherein the cell reselection to the second network node using the second subscription is triggered in response to the forbidden tracking area list provided to the second subscription.
The method of claim 1, further comprising:

triggering a cell reselection to the second network node using the first subscription in response to determining that the first service registration has failed;

performing a subsequent service registration using the first subscription to register with the service network or the different service network via the second network node in response to triggering the cell reselection to the second network node using the first subscription; and

determining whether the subsequent service registration is successful,

wherein the cell reselection to the second network node using the second subscription is triggered in response to determining that the first service registration has failed and that the subsequent service registration is successful.
The method of claim 7, further comprising:

determining that the subsequent service registration has failed; and

triggering a cell reselection to a third network node using the second subscription in response to determining that the subsequent service registration has failed, the third network node being associated with a third tracking area different from the first and second tracking areas.
The method of claim 1, further comprising:

determining that the second service registration has failed;

triggering a cell reselection to a third network node using the first subscription in response to determining that the second service registration has failed, the third network node being associated with a third tracking area different from the first and second tracking areas; and

performing a third service registration using the first subscription to register with the service network via the third network node in response to triggering the cell reselection to the third network node using the first subscription.
The method of claim 1, further comprising:

performing a cell search for a network node associated with a tracking area different from the first tracking area in response to determining that the first service registration has failed,

wherein the cell reselection to the second network node is triggered when the cell search finds the second network node.
The method of claim 1, further comprising:

selecting the second network node among a plurality of network nodes based on priority values respectively associated with the plurality of network nodes and in response to determining that the first service registration has failed,

wherein the cell reselection to the second network node using the second subscription is triggered subsequent to selecting the second network node.
The method of claim 11, wherein the priority values are based on signal strength values respectively associated with the plurality of network nodes.
The method of claim 1, wherein a radio access technology (RAT) of the first network node is same as a RAT of the second network node.
The method of claim 13, wherein the RAT of the first network node and the RAT of the second network node are based on 5G New Radio (NR) technology, and the first and second network nodes are general node Bs (gNBs) .
A user equipment (UE) for wireless communication and configured to communicate using multiple subscriptions, comprising:

at least one processor;

a transceiver communicatively coupled to the at least one processor; and

a memory communicatively coupled to the at least one processor,

wherein the at least one processor is configured to:

perform a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area;

determine that the first service registration using the first subscription has failed;

trigger a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, the second network node being associated with a second tracking area different from the first tracking area; and

perform a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription.
The UE of claim 15, wherein the at least one processor is further configured to:

perform data communication based on the second service registration using the second subscription subsequent to performing the second service registration.
The UE of claim 15, wherein the first service registration is performed using a first packet session established with the first network node using the first subscription, and wherein the at least one processor is further configured to:

establish a second packet session with the second network node using the second subscription in response to triggering the cell reselection to the second network using the second subscription, wherein the second service registration is performed using the second packet session.
The UE of claim 15, wherein the at least one processor is further configured to:

prevent the UE from selecting the first network node for service registration using the second subscription in response to determining that the first service registration has failed.
The UE of claim 15, wherein the at least one processor is further configured to:

generate or updating a forbidden tracking area list by adding the first tracking area associated with the first network node to the forbidden tracking area list in response to determining that the first registration with the first network node has failed,

wherein the cell reselection to the second network node using the second subscription is triggered based on the forbidden tracking area list.
The UE of claim 19, wherein the at least one processor configured to trigger the cell reselection to the second network node using the second subscription is configured to:

provide the forbidden tracking area list to the second subscription, wherein the cell reselection to the second network node using the second subscription is triggered in response to the forbidden tracking area list provided to the second subscription.
The UE of claim 15, wherein the at least one processor is further configured to:

trigger a cell reselection to the second network node using the first subscription in response to determining that the first service registration has failed;

perform a subsequent service registration using the first subscription to register with the service network or the different service network via the second network node in response to triggering the cell reselection to the second network node using the first subscription; and

determine whether the subsequent service registration is successful,

wherein the cell reselection to the second network node using the second subscription is triggered in response to determining that the first service registration has failed and that the subsequent service registration is successful.
The UE of claim 21, wherein the at least one processor is further configured to:

determine that the subsequent service registration has failed; and

trigger a cell reselection to a third network node using the second subscription in response to determining that the subsequent service registration has failed, the third network node being associated with a third tracking area different from the first and second tracking areas.
The UE of claim 15, wherein the at least one processor is further configured to:

determine that the second service registration has failed;

trigger a cell reselection to a third network node using the first subscription in response to determining that the second service registration has failed, the third network node being associated with a third tracking area different from the first and second tracking areas; and

perform a third service registration using the first subscription to register with the service network via the third network node in response to triggering the cell reselection to the third network node using the first subscription.
The UE of claim 15, wherein the at least one processor is further configured to:

perform a cell search for a network node associated with a tracking area different from the first tracking area in response to determining that the first service registration has failed,

wherein the cell reselection to the second network node is triggered when the cell search finds the second network node.
The UE of claim 15, wherein the at least one processor is further configured to:

select the second network node among a plurality of network nodes based on priority values respectively associated with the plurality of network nodes and in response to determining that the first service registration has failed,

wherein the cell reselection to the second network node using the second subscription is triggered subsequent to selecting the second network node.
The UE of claim 25, wherein the priority values are based on signal strength values respectively associated with the plurality of network nodes.
The UE of claim 15, wherein a radio access technology (RAT) of the first network node is same as a RAT of the second network node.
The UE of claim 27, wherein the RAT of the first network node and the RAT of the second network node are based on 5G New Radio (NR) technology, and the first and second network nodes are general node Bs (gNBs) .
A non-transitory processor-readable storage medium having instructions stored thereon for a user equipment (UE) configured to communicate using multiple subscriptions, wherein the instructions, when executed by a processing circuit, cause the processing circuit to:

perform a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area;

determine that the first service registration using the first subscription has failed;

trigger a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, the second network node being associated with a second tracking area different from the first tracking area; and

perform a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription.
The non-transitory processor-readable storage medium of claim 29, wherein the instructions further cause the processing circuit to:

perform data communication based on the second service registration using the second subscription subsequent to performing the second service registration.
The non-transitory processor-readable storage medium of claim 29, wherein the first service registration is performed using a first packet session established with the first network node using the first subscription, and wherein the instructions further cause the processing circuit to:

establish a second packet session with the second network node using the second subscription in response to triggering the cell reselection to the second network using the second subscription, wherein the second service registration is performed using the second packet session.
The non-transitory processor-readable storage medium of claim 29, wherein the instructions further cause the processing circuit to:

prevent the UE from selecting the first network node for service registration using the second subscription in response to determining that the first service registration has failed.
The non-transitory processor-readable storage medium of claim 29, wherein the instructions further cause the processing circuit to:

generate or updating a forbidden tracking area list by adding the first tracking area associated with the first network node to the forbidden tracking area list in response to determining that the first registration with the first network node has failed,

wherein the cell reselection to the second network node using the second subscription is triggered based on the forbidden tracking area list.
The non-transitory processor-readable storage medium of claim 33, wherein the instructions that cause the processing circuit to trigger the cell reselection to the second network node using the second subscription cause the processing circuit to:

provide the forbidden tracking area list to the second subscription, wherein the cell reselection to the second network node using the second subscription is triggered in response to the forbidden tracking area list provided to the second subscription.
The non-transitory processor-readable storage medium of claim 29, wherein the instructions further cause the processing circuit to:

trigger a cell reselection to the second network node using the first subscription in response to determining that the first service registration has failed;

perform a subsequent service registration using the first subscription to register with the service network or the different service network via the second network node in response to triggering the cell reselection to the second network node using the first subscription; and

determine whether the subsequent service registration is successful,

wherein the cell reselection to the second network node using the second subscription is triggered in response to determining that the first service registration has failed and that the subsequent service registration is successful.
The non-transitory processor-readable storage medium of claim 35, wherein the instructions further cause the processing circuit to:

determine that the subsequent service registration has failed; and

trigger a cell reselection to a third network node using the second subscription in response to determining that the subsequent service registration has failed, the third network node being associated with a third tracking area different from the first and second tracking areas.
The non-transitory processor-readable storage medium of claim 29, wherein the instructions further cause the processing circuit to:

determine that the second service registration has failed;

trigger a cell reselection to a third network node using the first subscription in response to determining that the second service registration has failed, the third network node being associated with a third tracking area different from the first and second tracking areas; and

perform a third service registration using the first subscription to register with the service network via the third network node in response to triggering the cell reselection to the third network node using the first subscription.
The non-transitory processor-readable storage medium of claim 29, wherein the instructions further cause the processing circuit to:

perform a cell search for a network node associated with a tracking area different from the first tracking area in response to determining that the first service registration has failed,

wherein the cell reselection to the second network node is triggered when the cell search finds the second network node.
The non-transitory processor-readable storage medium of claim 29, wherein the instructions further cause the processing circuit to:

select the second network node among a plurality of network nodes based on priority values respectively associated with the plurality of network nodes and in response to determining that the first service registration has failed,

wherein the cell reselection to the second network node using the second subscription is triggered subsequent to selecting the second network node.
The non-transitory processor-readable storage medium of claim 39, wherein the priority values are based on signal strength values respectively associated with the plurality of network nodes.
The non-transitory processor-readable storage medium of claim 29, wherein a radio access technology (RAT) of the first network node is same as a RAT of the second network node.
The non-transitory processor-readable storage medium of claim 41, wherein the RAT of the first network node and the RAT of the second network node are based on 5G New Radio (NR) technology, and the first and second network nodes are general node Bs (gNBs) .
A user equipment (UE) for wireless communication and configured to communicate using multiple subscriptions, comprising:

means for performing a first service registration using a first subscription to register with a service network via a first network node associated with a first tracking area;

means for determining that the first service registration using the first subscription has failed;

means for triggering a cell reselection to a second network node using a second subscription in response to determining that the first service registration has failed, the second network node being associated with a second tracking area different from the first tracking area; and

means for performing a second service registration using the second subscription to register with the service network or a different service network via the second network node in response to triggering the cell reselection to the second network using the second subscription.