WO2021232420A1

WO2021232420A1 - Disabling dual connectivity at a multi-subscriber identity module user equipment

Info

Publication number: WO2021232420A1
Application number: PCT/CN2020/091879
Authority: WO
Inventors: Hao Zhang; Tianya LIN; Haibo Liu
Original assignee: Qualcomm Incorporated
Priority date: 2020-05-22
Filing date: 2020-05-22
Publication date: 2021-11-25

Abstract

Methods, systems, and devices for wireless communications are described. If a user equipment (UE) identifies that a base station is rejecting tracking area update (TAU) requests used to disable dual connectivity communications for a first subscription, the UE may add a public land mobile network (PLMN) that includes the base station to a list of problematic PLMNs. The list of problematic PLMNs may include PLMNs that are unable to handle TAU requests for disabling dual connectivity communications. The UE may then send the newly added PLMN or the updated list of PLMNs from the first subscription to a second subscription. As such, the UE may avoid transmitting TAU requests to the base station to disable dual connectivity communications with the base station for the second subscription. Instead, the UE may transmit an attach request to disable dual connectivity communications with the base station for the second subscription.

Description

DISABLING DUAL CONNECTIVITY AT A MULTI-SUBSCRIBER IDENTITY MODULE USER EQUIPMENT

FIELD OF TECHNOLOGY

The following relates generally to wireless communications and more specifically to disabling dual connectivity at a multi-subscriber identity module (SIM) user equipment (UE) .

BACKGROUND

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) .

A wireless multiple-access communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) . In some wireless communications systems, a UE may support communications with a base station using multiple radio access technologies (RATs) , such as 5G, LTE, etc. Improved techniques at a UE for communicating with a base station using one or more RATs may be desirable.

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support disabling dual connectivity at a multi-subscriber identity module (SIM) user equipment (UE) . The multi-SIM UE may include a first SIM supporting a first subscription at the UE and a second SIM supporting a second subscription at the UE. If the UE identifies that a base station is rejecting tracking area update (TAU) requests used to disable dual connectivity communications for the first subscription, the UE may add a public land mobile network (PLMN) that includes the base station to a list of problematic PLMNs. The list of problematic PLMNs may include PLMNs that are unable to handle TAU requests for disabling dual connectivity communications. The UE may then send the newly added PLMN or the updated list of PLMNs with the newly added PLMN from the first subscription to the second subscription. As such, the UE may avoid transmitting TAU requests to the base station to disable dual connectivity communications with the base station for the second subscription. Instead, the UE may transmit an attach request to disable dual connectivity communications with the base station for the second subscription.

A method of wireless communication at a UE is described. The method may include identifying that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected, adding a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based on the identifying, and sending, based on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE.

An apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to identify that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected, add a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based on the identifying, and send, based on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE.

Another apparatus for wireless communication at a UE is described. The apparatus may include means for identifying that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected, adding a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based on the identifying, and sending, based on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE.

A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to identify that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected, add a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based on the identifying, and send, based on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to the base station, an attach request to disable dual connectivity communications for the first subscription based on adding the public land mobile network to the list. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the attach request to disable dual connectivity communications for the first subscription may include operations, features, means, or instructions for transmitting the attach request with a dual connectivity flag disabled.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining to disable dual connectivity communications with the base station for the second subscription at the UE, and transmitting, to the base station, an attach request to disable dual connectivity communications for the second subscription based on adding the public land mobile network to the list. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the attach request to disable dual connectivity communications for the second subscription may include operations, features, means, or instructions for transmitting the attach request with a dual connectivity flag disabled.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, identifying that the at least one tracking area update request may be rejected may include operations, features, means, or instructions for identifying that the at least one tracking area update request may be rejected with a rejection cause indicating a protocol error, where adding the public land mobile network to the list may be based on the rejection cause indicating the protocol error. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, identifying that the at least one tracking area update request may be rejected may include operations, features, means, or instructions for identifying that a threshold number of tracking area update requests to disable dual connectivity communications with the base station for the first subscription at the UE may be rejected, where adding the public land mobile network to the list may be based on the threshold number of tracking area update request being rejected.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, identifying that the at least one tracking area update request may be rejected may include operations, features, means, or instructions for transmitting, to the base station, the at least one tracking area update request to disable dual connectivity communications with the base station for the first subscription, and receiving, from the base station, at least one tracking area update reject message indicating that the at least one tracking area update request may be rejected. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, disabling dual-connectivity communications may include operations, features, means, or instructions for disabling communications using a 5G radio access technology.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communications system that supports disabling dual connectivity at a multi-subscriber identity module (SIM) user equipment (UE) in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system that supports disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of a process flow that supports disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure.

FIGs. 4 and 5 show block diagrams of devices that support disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure.

FIG. 6 shows a block diagram of a communications manager that supports disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure.

FIG. 7 shows a diagram of a system including a device that supports disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure.

FIG. 8 shows a flowchart illustrating methods that support disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

In some wireless communications systems, a user equipment (UE) may support communications with a base station using multiple radio access technologies (RATs) . Long-Term Evolution (LTE) and Fifth Generation (5G) are examples of different RATs. In some deployments, cells at a base station supporting 5G may be non-standalone (NSA) cells, where NSA cells may be cells that depend on the control plane of other cells for control functions. In such deployments, a UE may be anchored on an LTE cell, and the UE may exchange data with a 5G cell. For example, the UE, LTE cell, and 5G cell may each operate in an NSA mode, and the UE may use the LTE cell for control-plane signaling and use the 5G cell for user-plane signaling. Communications with the LTE cell and the 5G cell may be referred to as dual connectivity communications or communications in a dual-connectivity mode since the UE is connected to both the LTE cell and the 5G cell.

In some aspects, it may be appropriate for a UE to disable dual connectivity communications (e.g., disable communications with the 5G cell and communicate with the LTE cell) . In such aspects, the UE may transmit a tracking area update (TAU) request to a base station (e.g., the base station linked to the 5G cell and the LTE cell or linked to at least the LTE cell) to disable dual connectivity communications. In some cases, however, the base station may respond to the TAU request with an unexpected TAU reject message. For instance, the TAU reject message may indicate a protocol error in the rejection cause (e.g., error #111) , even if the UE followed the appropriate protocols for the TAU request. In such cases, instead of transmitting another TAU request to disable dual connectivity communications, the UE may transmit an attach request to disable dual connectivity communications. That is, the base station may be unable to handle TAU requests used to disable dual connectivity communications, but the base station may be able to handle attach requests used to disable dual connectivity communications.

Although the techniques described above allow a UE to disable dual connectivity communications, there may be some inefficiencies associated with these techniques at a UE supporting multiple subscriptions. As an example, if a UE determines to disable dual connectivity communications with a base station for a first subscription at the UE, the UE may transmit a TAU request to the base station to disable the dual connectivity communications. If the TAU request is rejected, the UE may use an attach request to disable the dual connectivity communications for the first subscription. Afterwards, if the UE determines to disable dual connectivity communications with the base station for a second subscription at the UE, the UE may also attempt to use a TAU request to disable the dual connectivity communications, before using an attach request to disable the dual connectivity communications. That is, even though the UE may have already determined that the base station is unable to handle TAU requests for disabling dual connectivity communications (e.g., for the first subscription) , the UE may still waste time and resources transmitting one or more TAU requests to disable the dual connectivity communications for the second subscription.

As described herein, a UE supporting multiple subscriptions may support efficient techniques for disabling dual connectivity communications with a base station. The UE supporting multiple subscriptions may include multiple subscriber identity modules (SIMs) each supporting a different subscription and may be referred to as a multi-SIM UE. For example, a multi-SIM UE may include a first SIM supporting a first subscription at the UE and a second SIM supporting a second subscription at the UE. If the UE identifies that a base station is rejecting TAU requests used to disable dual connectivity communications for the first subscription, the UE may add a public land mobile network (PLMN) that includes the base station to a list of problematic PLMNs. The list of problematic PLMNs may include PLMNs that are unable to handle TAU requests for disabling dual connectivity communications. The UE may then send the newly added PLMN or the updated list of PLMNs from the first subscription to the second subscription. As such, the UE may avoid transmitting TAU requests to the base station to disable dual connectivity communications with the base station for the second subscription. Instead, the UE may transmit an attach request to disable dual connectivity communications with the base station for the second subscription.

Aspects of the disclosure introduced above are described below in the context of a wireless communications system. Examples of processes and signaling exchanges that support disabling dual connectivity at a multi-SIM UE are then described. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to disabling dual connectivity at a multi-SIM UE.

FIG. 1 illustrates an example of a wireless communications system 100 that supports disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long-Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

The base stations 105 may be dispersed throughout a geographic area to form the wireless communications system 100 and may be devices in different forms or having different capabilities. The base stations 105 and the UEs 115 may wirelessly communicate via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base station 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which a base station 105 and a UE 115 may support the communication of signals according to one or more radio access technologies.

The UEs 115 may be dispersed throughout a coverage area 110 of the wireless communications system 100, and each UE 115 may be stationary, or mobile, or both at different times. The UEs 115 may be devices in different forms or having different capabilities. Some example UEs 115 are illustrated in FIG. 1. The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115, the base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment) , as shown in FIG. 1.

The base stations 105 may communicate with the core network 130, or with one another, or both. For example, the base stations 105 may interface with the core network 130 through one or more backhaul links 120 (e.g., via an S1, N2, N3, or other interface) . The base stations 105 may communicate with one another over the backhaul links 120 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) , or indirectly (e.g., via core network 130) , or both. In some examples, the backhaul links 120 may be or include one or more wireless links.

One or more of the base stations 105 described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or other suitable terminology.

A UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client, among other examples. A UE 115 may also include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples.

The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115 that may sometimes act as relays as well as the base stations 105 and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1.

The UEs 115 and the base stations 105 may wirelessly communicate with one another via one or more communication links 125 over one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links 125. For example, a carrier used for a communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP) ) that is operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR) . Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information) , control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communications system 100 may support communication with a UE 115 using carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers.

Signal waveforms transmitted over a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) . In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. A wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams) , and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE 115.

The time intervals for the base stations 105 or the UEs 115 may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of T _s= 1/ (Δf _max·N _f) seconds, where Δf _max may represent the maximum supported subcarrier spacing, and N _f may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms) ) . Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023) .

Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a number of slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on subcarrier spacing. Each slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . In some wireless communications systems 100, a slot may further be divided into multiple mini-slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N _f) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation.

A subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and may be referred to as a transmission time interval (TTI) . In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally, or alternatively, the smallest scheduling unit of the wireless communications system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) ) .

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET) ) for a physical control channel may be defined by a number of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) may be configured for a set of the UEs 115. For example, one or more of the UEs 115 may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or multiple control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to a number of control channel resources (e.g., control channel elements (CCEs) ) associated with encoded information for a control information format having a given payload size. Search space sets may include common search space sets configured for sending control information to multiple UEs 115 and UE-specific search space sets for sending control information to a specific UE 115.

Each base station 105 may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) , or others) . In some examples, a cell may also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) over which the logical communication entity operates. Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the base station 105. For example, a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with geographic coverage areas 110, among other examples.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs 115 with service subscriptions with the network provider supporting the macro cell. A small cell may be associated with a lower-powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to the UEs 115 with service subscriptions with the network provider or may provide restricted access to the UEs 115 having an association with the small cell (e.g., the UEs 115 in a closed subscriber group (CSG) , the UEs 115 associated with users in a home or office) . A base station 105 may support one or multiple cells and may also support communications over the one or more cells using one or multiple component carriers.

In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT) , enhanced mobile broadband (eMBB) ) that may provide access for different types of devices.

In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, the overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous network in which different types of the base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

The wireless communications system 100 may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 may be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications. The UEs 115 may be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission critical functions) . Ultra-reliable communications may include private communication or group communication and may be supported by one or more mission critical services such as mission critical push-to-talk (MCPTT) , mission critical video (MCVideo) , or mission critical data (MCData) . Support for mission critical functions may include prioritization of services, and mission critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission critical, and ultra-reliable low-latency may be used interchangeably herein.

In some examples, a UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol) . One or more UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105 or be otherwise unable to receive transmissions from a base station 105. In some examples, groups of the UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some examples, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between the UEs 115 without the involvement of a base station 105.

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or 5G core (5GC) , which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME) , an access and mobility management function (AMF) ) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs 115 served by the base stations 105 associated with the core network 130. User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to the network operators IP services 150. The operators IP services 150 may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched Streaming Service.

Some of the network devices, such as a base station 105, may include subcomponents such as an access network entity 140, which may be an example of an access node controller (ANC) . Each access network entity 140 may communicate with the UEs 115 through one or more other access network transmission entities 145, which may be referred to as radio heads, smart radio heads, or transmission/reception points (TRPs) . Each access network transmission entity 145 may include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., a base station 105) .

The wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz) . Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length. The UHF waves may be blocked or redirected by buildings and environmental features, but the waves may penetrate structures sufficiently for a macro cell to provide service to the UEs 115 located indoors. The transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

The wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, devices such as the base stations 105 and the UEs 115 may employ carrier sensing for collision detection and avoidance. In some examples, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

A base station 105 or a UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally, or alternatively, an antenna panel may support radio frequency beamforming for a signal transmitted via an antenna port.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105, a UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that some signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying amplitude offsets, phase offsets, or both to signals carried via the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .

The wireless communications system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or a core network 130 supporting radio bearers for user plane data. At the physical layer, transport channels may be mapped to physical channels.

In wireless communications system 100, a UE 115 may support communications with a base station using multiple RATs. LTE and 5G are examples of different RATs. In some deployments, cells at a base station supporting 5G may be NSA cells. NSA cells may be cells that depend on the control plane of other cells for control functions. In such deployments, a UE 115 may be anchored on an LTE cell, and the UE 115 may exchange data with a 5G cell. For example, the UE 115, LTE cell, and 5G cell may each operate in an NSA mode, and the UE 115 may use the LTE cell for control-plane signaling and use the 5G cell for user-plane signaling. Communications with the LTE cell and the 5G cell may be referred to as dual connectivity communications or communications in a dual-connectivity mode. In some aspects, it may be appropriate for a UE to disable dual connectivity communications (e.g., disable communications with the 5G cell and communicate with the LTE cell) . In such aspects, the UE 115 may transmit a TAU request to a base station 105 (e.g., the base station 105 linked to the 5G cell and the LTE cell or linked to at least the LTE cell) to disable dual connectivity communications.

In some deployments, the base station 105 may respond to the TAU request with an unexpected or unspecified TAU reject message. For instance, the TAU reject message may indicate a protocol error in the rejection cause (e.g., error #111) , even if the UE 115 followed the appropriate protocols for the TAU request. That is, the base station 105 may be unable to handle TAU requests used to disable dual connectivity communications. Thus, instead of transmitting another TAU request to disable dual connectivity communications, the UE 115 may transmit an attach request to disable dual connectivity communications. Further, the UE 115 may add a PLMN that includes the base station 105 to a list of problematic PLMNs, and the UE 115 may avoid transmitting TAU requests to disable dual connectivity communications to base stations 105 in any of the PLMNs in the list of problematic PLMNs.

In some cases, however, if the UE 115 supports multiple subscriptions, each subscription may maintain a list of problematic PLMNs. In such cases, even though a UE 115 may identify that a base station 105 is in a problematic PLMN for a first subscription, the UE 115 may still transmit TAU requests to the base station 105 to disable dual connectivity communications for a second subscription. As a result, the UE 115 may waste time and resources attempting to disable dual connectivity communications using TAU requests for the second subscription. A UE 115 supporting multiple subscriptions in wireless communications system 100 may support efficient techniques for disabling dual connectivity communications with a base station 105. For instance, a second subscription at a UE 115 may identify that a PLMN was added to a list of problematic PLMNs for a first subscription, and the second subscription may transmit an attach request to disable dual connectivity communications with a base station 105 without first transmitting a TAU request to disable dual connectivity communications.

FIG. 2 illustrates an example of a wireless communications system 200 that supports disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure. The wireless communications system 200 includes a UE 115-a, which may be an example of a UE 115 described with reference to FIG. 1. The UE 115-a may support multiple subscriptions and may be referred to as a multi-SIM UE or a dual SIM dual standby (DSDS) UE. The wireless communications system 200 also includes a base station 105-a, which may be an example of a base station 105 described with reference to FIG. 1. The base station 105-a may provide communication coverage for a coverage area 110-a. The wireless communications system 200 may implement aspects of wireless communications system 100. For example, the UE 115-a in wireless communications system 200 may support efficient techniques for disabling dual connectivity communications with the base station 105-a.

In the example of FIG. 2, the UE 115-a may communicate using a first subscription 205-a and a second subscription 205-b with multiple cells linked to one or more base stations 105 including the base station 105-a. For instance, the UE 115-a may be operating in a dual connectivity mode and may be communicating with a first cell (e.g., LTE cell) and a second cell (e.g., 5G cell) . The UE 115-a may be anchored to the first cell for control plane signaling and may exchange data with the second cell. Thus, the base station 105-a may be linked to the first cell and may or may not be linked to the second cell (i.e., the second cell may be linked to another base station 105) .

The UE 115-a may determine to disable dual connectivity communications for the first subscription 205-a with the multiple cells, and the UE 115-a may transmit a TAU request 210 to the base station 105-a to disable the dual connectivity communications for the first subscription 205-a. However, the base station 105-a may respond with a TAU reject message 215 rejecting the request to disable the dual connectivity communications for the first subscription 205-a. The TAU reject message 215 may indicate an unexpected rejection cause, such as a protocol error (e.g., error #111) . Unexpected rejection causes may correspond to rejection causes that the UE 115-a is unable to handle. For instance, if a rejection cause is not in a set of rejection causes that the UE 115-a is capable of handling, or if the rejection cause is in a set of rejection causes that the UE 115-a is unable to handle, the rejection cause may be considered or classified as an unexpected rejection cause.

Thus, the UE 115-a may transmit an attach request 220 to the base station 105-a to disable the dual connectivity communications for the first subscription 205-a. The UE 115-a may then add a PLMN that includes the base station 105-a to a list of problematic PLMNs. The list of problematic PLMNs may correspond to PLMNs that include base stations 105 that are unable to handle TAU requests used to disable dual connectivity communications. Thus, whenever the UE 115-a transitions back to operating in a dual connectivity mode for dual connectivity communications using the first subscription, and the UE 115-a determines to disable dual connectivity communications, the UE 115-a may avoid transmitting TAU requests to the base station 105-a to disable the dual connectivity communications. That is, the UE 115-a may determine that the PLMN that includes the base station 105-a is in the list of problematic PLMNs, and the UE 115-a may avoid transmitting TAU requests to the base station 105-a to disable the dual connectivity communications for the first subscription 205-a based on determining that the PLMN that includes the base station 105-a is in the list of problematic PLMNs.

Additionally, as described herein, the UE 115-a may send a message 225 from the first subscription 205-a at the UE 115 to the second subscription 205-b at the UE 115-a identifying the PLMN that includes the base station 105-a or a list of problematic PLMNs (e.g., the list of PLMNs to which the PLMN that includes the base station 105-a was added based on receiving the TAU reject message 215 for the first subscription 205-a) . The UE 115-a may then update a list of problematic PLMNs at the second subscription 205-b to be the same as the list of problematic PLMNs at the first subscription 205-a. The UE 115-a may send the message 225 internally from a processor at the first subscription (e.g., at a first SIM) to a processor at the second subscription (e.g., at the second SIM) . The UE 115-a may store the list of problematic PLMNs at each subscription (e.g., each SIM) . Additionally, or alternatively, the UE 115 may store the list of problematic PLMNs at a location in the UE 115-a accessible by the first subscription 205-a and the second subscription 205-b.

In any case, once a PLMN is added to a list of problematic PLMNs for the first subscription 205-a, the UE 115 may indicate to the second subscription 205-b that the PLMN is added to the list of problematic PLMNs. Similarly, once a PLMN is added to a list of problematic PLMNs for the second subscription 205-b, the UE 115 may indicate to the first subscription 205-a that the PLMN is added to the list of problematic PLMNs. Thus, the first subscription 205-a and the second subscription 205-b may share a list of problematic PLMNs (e.g., even if the list of problematic PLMNs is stored separately at each subscription) . Accordingly, if the UE 115-a determines to disable dual connectivity communications with the multiple cells for the second subscription 205-b, the UE 115-a may determine if the list of problematic PLMNs includes a PLMN associated with the base station 105-a. In the example of FIG. 2, the UE 115-a may determine that the list of problematic PLMNs includes the PLMN associated with the base station 105-a. Thus, instead of transmitting a TAU request to disable dual connectivity communications for the second subscription 205-b, the UE 115-a may transmit an attach request 220 to disable the dual connectivity communications for the second subscription 205-b.

FIG. 3 illustrates an example of a process flow 300 that supports disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure. Process flow 300 illustrates aspects of techniques performed by a UE 115-b, which may be an example of a UE 115 described with reference to FIGs. 1 and 2. For example, the UE 115-b may support multiple subscriptions including a first subscription 305-a and a second subscription 305-b, and the UE 115-b may be referred to as a multi-SIM UE or a DSDS UE. Process flow 300 also illustrates aspects of techniques performed by a base station 105-b, which may be an example of a base station 105 described with reference to FIGs. 1 and 2. Process flow 300 may implement aspects of

wireless communications systems

100 and 200. For example, the UE 115-b may support efficient techniques for disabling dual connectivity communications with the base station 105-b.

At 310, the UE 115-b may transmit an attach request to the base station 105-b using the second subscription 305-b to attach to the base station 105-b for dual connectivity communications with multiple cells using the second subscription 305-b. For instance, the UE 115-b may transmit the attach request with a DCNR flag enabled to enable dual connectivity communications. At 315, the base station 105-b may respond to the attach request for the second subscription 305-a with an attach accept message. Similarly, at 320, the UE 115-b may transmit an attach request to the base station 105-b using the first subscription 305-a to attach to the base station 105-b for dual connectivity communications with multiple cells using the first subscription 305-a. For instance, the UE 115-b may transmit the attach request with a DCNR flag enabled to enable dual connectivity communications. At 325, the base station 105-b may respond to the attach request for the first subscription 305-a with an attach accept message. Thus, the UE 115-b may attach to the base station 105-b using the first subscription 305-a and the second subscription 305-b for dual connectivity communications with multiple cells. The multiple cells may be at the base station 105-b or at multiple base stations 105 including the base station 105-b. For instance, the multiple cells may include a first cell (e.g., LTE cell) and a second cell (e.g., 5G cell) , where the UE 115-b is anchored on the first cell, and at least the first cell is located at the base station 105-b.

At 330, the UE 115-b may determine to disable dual connectivity communications for the first subscription 305-a. Specifically, the UE 115-b may decide to disable communications with the second cell. Thus, at 335, the UE 115-b may determine whether a PLMN that includes the base station 105 with the second cell (e.g., the base station 105-b or another base station 105) is in a list of problematic PLMNs. The list of problematic PLMNs may include PLMNs that are unable to handle TAU requests for disabling dual connectivity communications (e.g., the PLMNs may each include one or more base stations that are unable to handle TAU requests for disabling dual connectivity communications) . If the PLMN that includes the base station 105 with the second cell is not included in the list of problematic PLMNs, the UE 115-b may attempt to use one or more TAU requests to disable dual connectivity communications. For instance, at 340, the UE 115-b may transmit a TAU request to the base station 105-b to disable dual connectivity communications with the base station 105-b for the first subscription 305-a (e.g., TAU request with a DCNR flag disabled) . At 345, the UE 115-b may then receive a TAU reject message from the base station 105-b indicating that the TAU request is rejected.

Based on receiving the TAU reject message, the UE 115-b may identify that at least one TAU request to disable dual connectivity communications with the base station 105-b for the first subscription 305-a at the UE 115-b is rejected. Thus, at 350, the UE 115-b, using the first subscription 305-a, may add the PLMN that includes the base station 105 with the second cell to the list of problematic PLMNs. In some cases, the UE 115-b may add the PLMN that includes the base station 105 with the second cell to the list of problematic PLMNs if the UE 115-b identifies that the TAU reject message includes a rejection cause indicating a protocol error or another unexpected or unspecified error. Further, the UE 115-b may add the PLMN that includes the base station 105 with the second cell to the list of problematic PLMNs if the UE 115-b identifies that a threshold number of TAU requests to disable dual connectivity communications with the first and second cells for the first subscription 305-a are rejected (e.g., with unexpected rejection causes) .

At 355, the UE 115-b may, based on adding the PLMN to the list of problematic PLMNs, send a message identifying the PLMN, identifying the list of problematic PLMNs, or identifying both the PLMN and the list of problematic PLMNs from the first subscription 305-a at the UE 115-b to the second subscription 305-b at the UE 115-b. The message may be referred to as a replace-TAU-list synchronization message. Thus, the list of problematic PLMNs may be replaced or updated across the subscriptions at the UE 115-b such that the same list of problematic PLMNs is shared by the subscriptions 305 at the UE 115-b. After sending the message at 355 from the first subscription 305-a to the second subscription 305-b, or after determining that the PLMN that includes the base station 105 with the second cell is not included in the list of problematic PLMNs at 335, the UE 115-b may use an attach procedure to disable dual connectivity communications for the first subscription 305-a. At 360, the UE 115-b may transmit, to the base station 105-b, an attach request to disable dual connectivity communications for the first subscription 305-a based on adding the PLMN to the list at 350. For instance, the UE 115-b may transmit the attach request with a disabled dual connectivity flag. At 365, the UE 115-b may receive an attach accept message from the base station 105-b.

At 370, the UE 115-b may determine to disable dual connectivity communications with the base station 105-b for the second subscription 305-b at the UE 115-b. However, because the UE 115-b, using the second subscription 305-b, may identify that the PLMN that includes the base station 105 with the second cell is in a list of problematic PLMNs (e.g., based on receiving the PLMN or PLMN list at 355) , the UE 115-b may avoid transmitting one or more TAU requests to disable dual connectivity communications for the second subscription 305-b. Instead, the UE 115-b may use an attach procedure to disable dual connectivity communications for the second subscription 305-b. In particular, at 375, the UE 115-b may transmit, to the base station 105-b, an attach request to disable dual connectivity communications for the second subscription 305-b based on adding the PLMN to the list at 350. For instance, the UE 115-b may transmit the attach request with a disabled dual connectivity flag. At 380, the UE 115-b may receive an attach accept message from the base station 105-b indicating that the attach procedure was successful and that dual-connectivity communications were successfully disabled.

FIG. 4 shows a block diagram 400 of a device 405 that supports disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure. The device 405 may be an example of aspects of a UE 115 as described herein. The device 405 may include a receiver 410, a communications manager 415, and a transmitter 420. The device 405 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 410 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to disabling dual connectivity at a multi-SIM UE, etc. ) . Information may be passed on to other components of the device 405. The receiver 410 may be an example of aspects of the transceiver 720 described with reference to FIG. 7. The receiver 410 may utilize a single antenna or a set of antennas.

The communications manager 415 may identify that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected, add a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based on the identifying, and send, based on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE. The communications manager 415 may be an example of aspects of the communications manager 710 described herein.

The communications manager 415, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 415, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC) , a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 415, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 415, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 415, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 420 may transmit signals generated by other components of the device 405. In some examples, the transmitter 420 may be collocated with a receiver 410 in a transceiver module. For example, the transmitter 420 may be an example of aspects of the transceiver 720 described with reference to FIG. 7. The transmitter 420 may utilize a single antenna or a set of antennas.

FIG. 5 shows a block diagram 500 of a device 505 that supports disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure. The device 505 may be an example of aspects of a device 405, or a UE 115 as described herein. The device 505 may include a receiver 510, a communications manager 515, and a transmitter 530. The device 505 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to disabling dual connectivity at a multi-SIM UE, etc. ) . Information may be passed on to other components of the device 505. The receiver 510 may be an example of aspects of the transceiver 720 described with reference to FIG. 7. The receiver 510 may utilize a single antenna or a set of antennas.

The communications manager 515 may be an example of aspects of the communications manager 415 as described herein. The communications manager 515 may include a TAU manager 520 and a PLMN manager 525. The communications manager 515 may be an example of aspects of the communications manager 710 described herein.

The TAU manager 520 may identify that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected. The PLMN manager 525 may add a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based on the identifying and send, based on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE.

The transmitter 530 may transmit signals generated by other components of the device 505. In some examples, the transmitter 530 may be collocated with a receiver 510 in a transceiver module. For example, the transmitter 530 may be an example of aspects of the transceiver 720 described with reference to FIG. 7. The transmitter 530 may utilize a single antenna or a set of antennas.

FIG. 6 shows a block diagram 600 of a communications manager 605 that supports disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure. The communications manager 605 may be an example of aspects of a communications manager 415, a communications manager 515, or a communications manager 710 described herein. The communications manager 605 may include a TAU manager 610, a PLMN manager 615, an attachment manager 620, and a dual connectivity manager 625. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The TAU manager 610 may identify that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected. The PLMN manager 615 may add a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based on the identifying. The PLMN manager 615 may send, based on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE.

The attachment manager 620 may transmit, to the base station, an attach request to disable dual connectivity communications for the first subscription based on adding the public land mobile network to the list. In some examples, the attachment manager 620 may transmit the attach request with a dual connectivity flag disabled. The dual connectivity manager 625 may determine to disable dual connectivity communications with the base station for the second subscription at the UE. In some examples, the attachment manager 620 may transmit, to the base station, an attach request to disable dual connectivity communications for the second subscription based on adding the public land mobile network to the list. In some examples, the attachment manager 620 may transmit the attach request with a dual connectivity flag disabled.

In some examples, the TAU manager 610 may identify that the at least one tracking area update request is rejected with a rejection cause indicating a protocol error, where adding the public land mobile network to the list is based on the rejection cause indicating the protocol error. In some examples, the TAU manager 610 may identify that a threshold number of tracking area update requests to disable dual connectivity communications with the base station for the first subscription at the UE are rejected, where adding the public land mobile network to the list is based on the threshold number of tracking area update request being rejected. In some examples, the TAU manager 610 may transmit, to the base station, the at least one tracking area update request to disable dual connectivity communications with the base station for the first subscription. In some examples, the TAU manager 610 may receive, from the base station, at least one tracking area update reject message indicating that the at least one tracking area update request is rejected. In some examples, disabling dual-connectivity communications includes disabling communications using a 5G radio access technology.

FIG. 7 shows a diagram of a system 700 including a device 705 that supports disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure. The device 705 may be an example of or include the components of device 405, device 505, or a UE 115 as described herein. The device 705 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 710, an I/O controller 715, a transceiver 720, an antenna 725, memory 730, and a processor 740. These components may be in electronic communication via one or more buses (e.g., bus 745) .

The communications manager 710 may identify that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected, add a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based on the identifying, and send, based on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE.

The I/O controller 715 may manage input and output signals for the device 705. The I/O controller 715 may also manage peripherals not integrated into the device 705. In some cases, the I/O controller 715 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 715 may utilize an operating system such as

or another known operating system. In other cases, the I/O controller 715 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 715 may be implemented as part of a processor. In some cases, a user may interact with the device 705 via the I/O controller 715 or via hardware components controlled by the I/O controller 715.

The transceiver 720 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 720 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 720 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 725. However, in some cases the device may have more than one antenna 725, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 730 may include RAM and ROM. The memory 730 may store computer-readable, computer-executable code 735 including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 730 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 740 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 740 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor 740. The processor 740 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 730) to cause the device 705 to perform various functions (e.g., functions or tasks supporting disabling dual connectivity at a multi-SIM UE) .

The code 735 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 735 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 735 may not be directly executable by the processor 740 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 8 shows a flowchart illustrating a method 800 that supports disabling dual connectivity at a multi-SIM UE in accordance with aspects of the present disclosure. The operations of method 800 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 800 may be performed by a communications manager as described with reference to FIGs. 4 through 7. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally, or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 805, the UE may identify that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected. The operations of 805 may be performed according to the methods described herein. In some examples, aspects of the operations of 805 may be performed by a TAU manager as described with reference to FIGs. 4 through 7.

At 810, the UE may add a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based on the identifying. The operations of 810 may be performed according to the methods described herein. In some examples, aspects of the operations of 810 may be performed by a PLMN manager as described with reference to FIGs. 4 through 7.

At 815, the UE may send, based on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE. The operations of 815 may be performed according to the methods described herein. In some examples, aspects of the operations of 815 may be performed by a PLMN manager as described with reference to FIGs. 4 through 7.

Embodiment 1: A method of wireless communication, comprising: identifying that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected, adding a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based at least in part on the identifying, and sending, based at least in part on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE.

Embodiment 2: The method of embodiment 1, further comprising: transmitting, to the base station, an attach request to disable dual connectivity communications for the first subscription based at least in part on adding the public land mobile network to the list.

Embodiment 3: The method of any of embodiments 1 or 2, wherein transmitting the attach request to disable dual connectivity communications for the first subscription comprises: transmitting the attach request with a dual connectivity flag disabled.

Embodiment 4: The method of any of embodiments 1 to 3, further comprising: determining to disable dual connectivity communications with the base station for the second subscription at the UE; and transmitting, to the base station, an attach request to disable dual connectivity communications for the second subscription based at least in part on adding the public land mobile network to the list.

Embodiment 5: The method of any of embodiments 1 to 4, wherein transmitting the attach request to disable dual connectivity communications for the second subscription comprises: transmitting the attach request with a dual connectivity flag disabled.

Embodiment 6: The method of any of embodiments 1 to 5, wherein identifying that the at least one tracking area update request is rejected comprises: identifying that the at least one tracking area update request is rejected with a rejection cause indicating a protocol error, wherein adding the public land mobile network to the list is based at least in part on the rejection cause indicating the protocol error.

Embodiment 7: The method of any of embodiments 1 to 6, wherein identifying that the at least one tracking area update request is rejected comprises: identifying that a threshold number of tracking area update requests to disable dual connectivity communications with the base station for the first subscription at the UE are rejected, wherein adding the public land mobile network to the list is based at least in part on the threshold number of tracking area update request being rejected.

Embodiment 8: The method of any of embodiments 1 to 7, wherein identifying that the at least one tracking area update request is rejected comprises: transmitting, to the base station, the at least one tracking area update request to disable dual connectivity communications with the base station for the first subscription; and receiving, from the base station, at least one tracking area update reject message indicating that the at least one tracking area update request is rejected.

Embodiment 9: The method of any of embodiments 1 to 8, wherein disabling dual-connectivity communications comprises disabling communications using a 5G radio access technology.

It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to various other wireless communications systems such as Ultra Mobile Broadband (UMB) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein.

Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include random-access memory (RAM) , read-only memory (ROM) , electrically erasable programmable ROM (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. ”

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A method for wireless communication at a user equipment (UE) , comprising:

identifying that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected;

adding a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based at least in part on the identifying; and

sending, based at least in part on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE.
The method of claim 1, further comprising:

transmitting, to the base station, an attach request to disable dual connectivity communications for the first subscription based at least in part on adding the public land mobile network to the list.
The method of any of claims 1 and 2, wherein transmitting the attach request to disable dual connectivity communications for the first subscription comprises:

transmitting the attach request with a dual connectivity flag disabled.
The method of any of claims 1 to 3, further comprising:

determining to disable dual connectivity communications with the base station for the second subscription at the UE; and

transmitting, to the base station, an attach request to disable dual connectivity communications for the second subscription based at least in part on adding the public land mobile network to the list.
The method of any of claims 1 to 4, wherein transmitting the attach request to disable dual connectivity communications for the second subscription comprises:

transmitting the attach request with a dual connectivity flag disabled.
The method of any of claims 1 to 5, wherein identifying that the at least one tracking area update request is rejected comprises:

identifying that the at least one tracking area update request is rejected with a rejection cause indicating a protocol error, wherein adding the public land mobile network to the list is based at least in part on the rejection cause indicating the protocol error.
The method of any of claims 1 to 6, wherein identifying that the at least one tracking area update request is rejected comprises:

identifying that a threshold number of tracking area update requests to disable dual connectivity communications with the base station for the first subscription at the UE are rejected, wherein adding the public land mobile network to the list is based at least in part on the threshold number of tracking area update request being rejected.
The method of any of claims 1 to 7, wherein identifying that the at least one tracking area update request is rejected comprises:

transmitting, to the base station, the at least one tracking area update request to disable dual connectivity communications with the base station for the first subscription; and

receiving, from the base station, at least one tracking area update reject message indicating that the at least one tracking area update request is rejected.
The method of any of claims 1 to 8, wherein:

disabling dual-connectivity communications comprises disabling communications using a 5G radio access technology.
An apparatus for wireless communication at a user equipment (UE) , comprising:

a processor,

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

identify that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected;

add a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based at least in part on the identifying; and

send, based at least in part on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE.
The apparatus of claim 10, wherein the instructions are further executable by the processor to cause the apparatus to:

transmit, to the base station, an attach request to disable dual connectivity communications for the first subscription based at least in part on adding the public land mobile network to the list.
The apparatus of any of claims 10 and 11, wherein the instructions to transmit the attach request to disable dual connectivity communications for the first subscription are executable by the processor to cause the apparatus to:

transmit the attach request with a dual connectivity flag disabled.
The apparatus of any of claims 10 to 12, wherein the instructions are further executable by the processor to cause the apparatus to:

determine to disable dual connectivity communications with the base station for the second subscription at the UE; and

transmit, to the base station, an attach request to disable dual connectivity communications for the second subscription based at least in part on adding the public land mobile network to the list.
The apparatus of any of claims 10 to 13, wherein the instructions to transmit the attach request to disable dual connectivity communications for the second subscription are executable by the processor to cause the apparatus to:

transmit the attach request with a dual connectivity flag disabled.
The apparatus of any of claims 10 to 14, wherein the instructions to identify that the at least one tracking area update request is rejected are executable by the processor to cause the apparatus to:

identify that the at least one tracking area update request is rejected with a rejection cause indicating a protocol error, wherein adding the public land mobile network to the list is based at least in part on the rejection cause indicating the protocol error.
The apparatus of any of claims 10 to 15, wherein the instructions to identify that the at least one tracking area update request is rejected are executable by the processor to cause the apparatus to:

identify that a threshold number of tracking area update requests to disable dual connectivity communications with the base station for the first subscription at the UE are rejected, wherein adding the public land mobile network to the list is based at least in part on the threshold number of tracking area update request being rejected.
The apparatus of any of claims 10 to 16, wherein the instructions to identify that the at least one tracking area update request is rejected are executable by the processor to cause the apparatus to:

transmit, to the base station, the at least one tracking area update request to disable dual connectivity communications with the base station for the first subscription; and

receive, from the base station, at least one tracking area update reject message indicating that the at least one tracking area update request is rejected.
The apparatus of any of claims 10 to 17, wherein the instructions to disable dual-connectivity communications are executable by the processor to cause the apparatus to disable communications using a 5G radio access technology.
An apparatus for wireless communication at a user equipment (UE) , comprising:

means for identifying that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected;

means for adding a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based at least in part on the identifying; and

means for sending, based at least in part on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE.
The apparatus of claim 19, further comprising:

means for transmitting, to the base station, an attach request to disable dual connectivity communications for the first subscription based at least in part on adding the public land mobile network to the list.
The apparatus of any of claims 19 and 20, wherein the means for transmitting the attach request to disable dual connectivity communications for the first subscription comprises:

means for transmitting the attach request with a dual connectivity flag disabled.
The apparatus of any of claims 19 to 21, further comprising:

means for determining to disable dual connectivity communications with the base station for the second subscription at the UE; and

means for transmitting, to the base station, an attach request to disable dual connectivity communications for the second subscription based at least in part on adding the public land mobile network to the list.
The apparatus of any of claims 19 to 22, wherein the means for transmitting the attach request to disable dual connectivity communications for the second subscription comprises:

means for transmitting the attach request with a dual connectivity flag disabled.
The apparatus of any of claims 19 to 23, wherein the means for identifying that the at least one tracking area update request is rejected comprises:

means for identifying that the at least one tracking area update request is rejected with a rejection cause indicating a protocol error, wherein adding the public land mobile network to the list is based at least in part on the rejection cause indicating the protocol error.
The apparatus of any of claims 19 to 24, wherein the means for identifying that the at least one tracking area update request is rejected comprises:

means for identifying that a threshold number of tracking area update requests to disable dual connectivity communications with the base station for the first subscription at the UE are rejected, wherein adding the public land mobile network to the list is based at least in part on the threshold number of tracking area update request being rejected.
The apparatus of any of claims 19 to 25, wherein the means for identifying that the at least one tracking area update request is rejected comprises:

means for transmitting, to the base station, the at least one tracking area update request to disable dual connectivity communications with the base station for the first subscription; and

means for receiving, from the base station, at least one tracking area update reject message indicating that the at least one tracking area update request is rejected.
The apparatus of any of claims 19 to 26, wherein the means for disabling dual-connectivity communications comprises means for disabling communications using a 5G radio access technology.
A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE) , the code comprising instructions executable by a processor to:

identify that at least one tracking area update request to disable dual connectivity communications with a base station for a first subscription at the UE is rejected;

add a public land mobile network that includes the base station to a list of public land mobile networks that are unable to handle tracking area update requests for disabling dual connectivity communications based at least in part on the identifying; and

send, based at least in part on the adding, a message identifying the public land mobile network, the list of public land mobile networks, or both, from the first subscription at the UE to a second subscription at the UE.
The non-transitory computer-readable medium of claim 28, wherein the instructions are further executable to:

transmit, to the base station, an attach request to disable dual connectivity communications for the first subscription based at least in part on adding the public land mobile network to the list.
The non-transitory computer-readable medium of any of claims 28 and 29, wherein the instructions to transmit the attach request to disable dual connectivity communications for the first subscription are executable to:

transmit the attach request with a dual connectivity flag disabled.
The non-transitory computer-readable medium of any of claims 28 to 30, wherein the instructions are further executable to:

determine to disable dual connectivity communications with the base station for the second subscription at the UE; and

transmit, to the base station, an attach request to disable dual connectivity communications for the second subscription based at least in part on adding the public land mobile network to the list.
The non-transitory computer-readable medium of any of claims 28 to 31, wherein the instructions to transmit the attach request to disable dual connectivity communications for the second subscription are executable to:

transmit the attach request with a dual connectivity flag disabled.
The non-transitory computer-readable medium of any of claims 28 to 32, wherein the instructions to identify that the at least one tracking area update request is rejected are executable to:

identify that the at least one tracking area update request is rejected with a rejection cause indicating a protocol error, wherein adding the public land mobile network to the list is based at least in part on the rejection cause indicating the protocol error.
The non-transitory computer-readable medium of any of claims 28 to 33, wherein the instructions to identify that the at least one tracking area update request is rejected are executable to:

identify that a threshold number of tracking area update requests to disable dual connectivity communications with the base station for the first subscription at the UE are rejected, wherein adding the public land mobile network to the list is based at least in part on the threshold number of tracking area update request being rejected.
The non-transitory computer-readable medium of any of claims 28 to 34, wherein the instructions to identify that the at least one tracking area update request is rejected are executable to:

transmit, to the base station, the at least one tracking area update request to disable dual connectivity communications with the base station for the first subscription; and

receive, from the base station, at least one tracking area update reject message indicating that the at least one tracking area update request is rejected.
The non-transitory computer-readable medium of any of claims 28 to 35, wherein the instructions to disable dual-connectivity communications are executable by the processor to cause the apparatus to disable communications using a 5G radio access technology.