Method and apparatus for post-call service recovery in dual SIM user equipment

Abstract

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may establish a first wireless connection associated with a first subscription using a first wireless access technology, and may establish a second wireless connection associated with a second subscription using a second wireless access technology. The UE may perform a call on the second wireless connection, and identify a loss of the first wireless connection based on performing the call on the second wireless connection. The UE may perform a network discovery procedure associated with the first subscription using the first wireless access technology based on the loss of the first wireless connection and the termination of the call on the second wireless connection.

Description

Technical Field

[0001] The following relates generally to wireless communications, and more particularly, to techniques for post-call service recovery in a dual SIM user device. Background Art

[0002] Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcasting, etc. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency and power). Examples of such multiple access systems include fourth generation (4G) systems (e.g., long term evolution (LTE) systems, improved LTE (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 use 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 communication system may include one or more base stations or one or more network access nodes, each base station or network access node simultaneously supporting communication for multiple communication devices (which may be further referred to as user equipment (UE)).

[0003] In some systems, a dual SIM user equipment (UE) is capable of supporting radio connections for cells associated with a first subscription and a second subscription. In some cases, the radio connections associated with the first subscription and the second subscription may share common UE hardware resources (e.g., a common modem) as well as common radio frequency (RF) resources. Therefore, a call (e.g., a voice call) performed over a second radio connection associated with the second subscription may cause the first radio connection associated with the first subscription to be lost. Once the call is terminated, a radio access technology acquisition process performed by the UE to reestablish the radio connection associated with the first subscription may cause the UE to first establish a radio connection associated with a lower priority radio access technology (e.g., 3G, 2G), thereby delaying service recovery associated with a higher priority radio access technology (e.g., NR). Summary of the invention

[0004] The described techniques relate to improved methods, systems, devices, and apparatuses that support techniques for post-call service recovery in dual SIM user devices. In summary, the described techniques provide for a dual SIM user device (UE) to perform (e.g., initiate or restart) a network discovery process (e.g., a radio access technology acquisition process) associated with a first subscription supported by the UE after a call (e.g., a voice call) performed by a second subscription supported by the UE is terminated. The network discovery process may prioritize higher priority radio access technologies (e.g., NR, 5G) over lower priority radio access technologies (e.g., LTE, 3G, 2G). By initiating (or restarting) the network discovery process after a call is terminated, the techniques described herein may facilitate fast and efficient NR service recovery and prevent delays associated with NR service recovery experienced by some wireless communication systems.

[0005] A method of wireless communication at a UE is described. The method may include: establishing a first wireless connection associated with a first subscription using a first wireless access technology; establishing a second wireless connection associated with a second subscription using a second wireless access technology; performing a call on the second wireless connection; identifying a loss of the first wireless connection based on performing the call on the second wireless connection; and performing a network discovery process associated with the first subscription using the first wireless access technology based on the loss of the first wireless connection and termination of the call on the second wireless connection.

[0006] An apparatus for wireless communication at a UE is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to perform the following operations: establish a first wireless connection associated with a first subscription using a first wireless access technology; establish a second wireless connection associated with a second subscription using a second wireless access technology; perform a call on the second wireless connection; identify a loss of the first wireless connection based on performing the call on the second wireless connection; and perform a network discovery process associated with the first subscription using the first wireless access technology based on the loss of the first wireless connection and the termination of the call on the second wireless connection.

[0007] Another apparatus for wireless communication at a UE is described. The apparatus may include means for establishing a first wireless connection associated with a first subscription using a first wireless access technology; establishing a second wireless connection associated with a second subscription using a second wireless access technology; performing a call on the second wireless connection; identifying a loss of the first wireless connection based on performing the call on the second wireless connection; and performing a network discovery process associated with the first subscription using the first wireless access technology based on the loss of the first wireless connection and termination of the call on the second wireless connection.

[0008] 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: establish a first wireless connection associated with a first subscription using a first wireless access technology; establish a second wireless connection associated with a second subscription using a second wireless access technology; perform a call on the second wireless connection; identify a loss of the first wireless connection based on performing the call on the second wireless connection; and perform a network discovery process associated with the first subscription using the first wireless access technology based on the loss of the first wireless connection and termination of the call on the second wireless connection.

[0009] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for initiating the network discovery process associated with the first subscription using the first wireless access technology based on the loss of the first wireless connection, wherein the network discovery process may be initiated before the termination of the call on the second wireless connection, and wherein performing the network discovery process based on the loss of the first wireless connection and the termination of the call on the second wireless connection includes restarting the network discovery process after the termination of the call on the second wireless connection.

[0010] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: starting an attachment attempt counter, a timer, or both based on starting the network discovery process; and performing the network discovery process using the second radio access technology based on the attachment attempt counter satisfying a threshold counter, the timer satisfying a threshold duration, or both.

[0011] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: resetting the attachment attempt counter, the timer, or both based on restarting the network discovery process after the termination of the call on the second wireless connection.

[0012] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: based on performing the network discovery process using the first radio access technology, establishing a third wireless connection associated with the first subscription using the first radio access technology.

[0013] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: when operating in an independent operation mode, performing an attachment procedure with a cell associated with the first subscription, wherein establishing the first wireless connection may be based on performing the attachment procedure.

[0014] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for performing the following operations: communicating on a first wireless connection associated with the first subscription using a set of communication resources based on establishing the first wireless connection; and performing the call on the second wireless connection using the set of communication resources, wherein identifying the loss of the first wireless connection can be based on performing the call on the second wireless connection using the set of communication resources.

[0015] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first wireless connection associated with the first subscription may be established using a set of RF hardware resources of the UE, and the second wireless connection associated with the second subscription may be established using the set of RF hardware resources of the UE.

[0016] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, performing the call on the second wireless connection may include operations, features, units, or instructions for performing the following operations: performing a Voice over LTE (VoLTE) call or a Circuit Switched Fallback (CSFB) call.

[0017] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first wireless access technology includes new radio technology, 5G technology, or both, and the second wireless access technology includes long term evolution technology, 4G technology, or both. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 An example of a wireless communication system supporting techniques for post-call service restoration in a dual SIM user device in accordance with aspects of the present disclosure is shown.

[0019] Figure 2 An example of a wireless communication system supporting techniques for post-call service restoration in a dual SIM user device in accordance with aspects of the present disclosure is shown.

[0020] Figure 3 An example of a process flow supporting techniques for post-call service restoration in a dual SIM user device in accordance with aspects of the present disclosure is shown.

[0021] Figure 4 and 5 A block diagram of a device supporting techniques for post-call service restoration in a dual SIM user device in accordance with aspects of the present disclosure is shown.

[0022] Figure 6 A block diagram of a communications manager supporting techniques for post-call service restoration in a dual SIM user device in accordance with aspects of the present disclosure is shown.

[0023] Figure 7 A diagram of a system including devices supporting techniques for post-call service restoration in a dual SIM user device is shown in accordance with aspects of the present disclosure.

[0024] Figures 8 to 10 A flow chart illustrating a method of supporting techniques for post-call service restoration in a dual SIM user device in accordance with aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0025] In some systems, a dual SIM user equipment (UE) may support multiple subscriptions, which allows the dual SIM UE to establish connections with multiple networks, where each subscription may support one network. In some aspects, the dual SIM UE may be able to establish a first wireless connection associated with the first subscription using a first radio access technology (e.g., NR technology), and additionally establish a second wireless connection associated with the second subscription using a second radio access technology (e.g., LTE technology). In some cases, the wireless connections associated with the first subscription and the second subscription may share common radio frequency (RF) hardware resources (e.g., a common modem) and common RF resources (e.g., time / frequency resources). Therefore, in some cases, the UE may perform a call (e.g., a voice call) on the second wireless connection using voice over LTE (VoLTE) or circuit switched fallback (CSFB), which may monopolize the common RF resources for the length of the call and cause a timeout and loss of the first wireless connection associated with the first subscription. The UE may then perform a network discovery process (e.g., a radio access technology acquisition process) associated with the first subscription using the first radio access technology (e.g., NR) to recover the first wireless connection. The network discovery process may be performed first using NR, and if a higher priority connection cannot be established, the network discovery process may then be performed using LTE, 3G, and 2G. However, due to the fact that the call associated with the second subscription is utilizing common RF resources, the UE's first subscription may not be able to reestablish a connection while the call is ongoing. Depending on the length of the call, the UE's first subscription may be trying to establish a lower priority connection (e.g., 3G connection, 2G connection) when the call is terminated. Therefore, when the call is terminated, the UE's first subscription is free to use the common RF resources and a lower priority connection may be established thereby. Establishing this lower priority connection may delay NR service recovery, thereby slowing down the call and resulting in a poor user experience.

[0026] To address issues associated with delayed NR service resumption after a call, a dual SIM UE may perform (e.g., initiate or restart) a network discovery process (e.g., a radio access technology acquisition process) associated with a first subscription after termination of a call performed on a second subscription. For example, a call (e.g., a voice call) associated with a second subscription and performed on a second radio connection may utilize common RF resources and may therefore result in loss of a first radio connection associated with the first subscription. Upon termination of the call, the UE may restart the network discovery process associated with the first subscription using a first radio access technology (e.g., NR). In this regard, by restarting the network discovery process after the call is terminated when common RF resources are available, the UE may be able to quickly establish a higher priority connection (e.g., an NR connection) associated with the first subscription. In particular, by restarting the network discovery process after the call is terminated, the UE may prevent a lower priority connection (e.g., LTE, 3G, 2G) from being established first, which may delay NR service resumption. Therefore, the techniques described herein may enable faster and more efficient resumption of NR services after termination of a call associated with a second subscription.

[0027] Aspects of the disclosure are first described in the context of a wireless communication system. Aspects of the disclosure are also described in the context of an example process flow. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flow diagrams relating to recovering a user equipment from a call failure in a new radio.

[0028] Figure 1 An example of a wireless communication system 100 supporting techniques for post-call service recovery in a dual SIM user device in accordance with aspects of the present disclosure is shown. The wireless communication 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 communication system 100 may be a long term evolution (LTE) network, an improved LTE (LTE-A) network, an LTE-A Pro network, or a new radio (NR) network. In some examples, the wireless communication system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low-latency communications, or communications with low-cost and low-complexity devices, or any combination thereof.

[0029] Base stations 105 may be dispersed throughout a geographic area to form wireless communication system 100, and may be devices of different forms or capabilities. Base stations 105 and UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which UEs 115 and base stations 105 may establish one or more communication links 125. Coverage area 110 may be an example of a geographic area over which base stations 105 and UEs 115 may support transmission of signals in accordance with one or more radio access technologies.

[0030] UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary, mobile, or both at different times. UEs 115 may be devices of different forms or with different capabilities. Figure 1 Some example UEs 115 are shown in FIG. 1. The UEs 115 described herein can communicate with various types of devices, such as other UEs 115, base stations 105, or network devices (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network devices), such as Figure 1 shown.

[0031] The base stations 105 may communicate with the core network 130, or communicate with each other, or perform both operations. For example, the base stations 105 may interface with the core network 130 via one or more backhaul links 120 (e.g., via S1, N2, N3 or other interfaces). The base stations 105 may communicate with each other directly (e.g., directly between the base stations 105) on the backhaul links 120 (e.g., via X2, Xn or other interfaces), or communicate with each other indirectly (e.g., via the core network 130), or perform both operations. In some examples, the backhaul links 120 may be or include one or more wireless links.

[0032] One or more of the base stations 105 described herein may include or may be referred to by those skilled in the art as a base station transceiver, a radio base station, an access point, a radio transceiver, a Node B, an evolved Node B (eNB), a next generation Node B, or a Gigabit Node B (any of which may be referred to as a gNB), a Home Node B, a Home Evolved Node B, or some other appropriate terminology.

[0033] 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 appropriate terminology, where a "device" may also be referred to as a unit, a station, a terminal, or a client, among other examples. 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, 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 communication (MTC) device, among other examples, which may be implemented in various items such as appliances, or vehicles, meters, and among other examples.

[0034] The UE 115 described herein is capable of communicating with various types of devices, such as other UEs 115, which may sometimes act as relays, as well as base stations 105 and network devices, including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, such as Figure 1 shown.

[0035] The UE 115 and the base station 105 may communicate wirelessly with each other via one or more communication links 125 on 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 link 125. For example, a carrier for the communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth portion (BWP)) that operates 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 to coordinate operations for the carrier, user data, or other signaling. The wireless communication system 100 may support communication with the UE 115 using carrier aggregation or multi-carrier operation. Depending on the carrier aggregation configuration, the UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation may be used with both frequency division duplex (FDD) component carriers and time division duplex (TDD) component carriers.

[0036] The signal waveform transmitted on the carrier may be composed of multiple subcarriers (e.g., using multicarrier 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 include a symbol period (e.g., the duration of a modulation symbol) and a subcarrier, wherein the symbol period and the 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). Therefore, the more resource elements received by the UE 115 and the higher the order of the modulation scheme, the higher the data rate for the UE 115 can be. Wireless communication resources may refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity for communication with the UE 115.

[0037] The basic time unit (which may be referred to as T s =1 / (Δf max ·N f ) seconds sampling period, where Δf max It can represent the maximum supported subcarrier spacing, and N f The time intervals for the base station 105 or the UE 115 may be expressed as multiples of a maximum supported discrete Fourier transform (DFT) size). The time intervals of the communication resources 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).

[0038] Each frame may include a plurality of consecutively numbered subframes or time slots, and each subframe or time 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 time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include a number of symbol periods (e.g., depending on the length of a cyclic prefix added in front of each symbol period). In some wireless communication systems 100, a time slot may be further divided into a plurality of micro-time slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N f The duration of a symbol period may depend on the subcarrier spacing or the operating frequency band.

[0039] A subframe, a time slot, a mini-time slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication 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 communication system 100 may be dynamically selected (e.g., in the form of bursts of shortened TTIs (sTTIs)).

[0040] Physical channels may be multiplexed on a carrier according to various techniques. For example, one or more of a time division multiplexing (TDM) technique, a frequency division multiplexing (FDM) technique, or a hybrid TDM-FDM technique may be used to multiplex physical control channels and physical data channels on a downlink carrier. A control region (e.g., a control resource set (CORESET)) for a physical control channel may be defined by the number of symbol periods and may extend across the system bandwidth of a carrier or a subset of the system bandwidth. One or more control regions (e.g., CORESETs) may be configured for a group of UEs 115. For example, one or more of the UEs 115 may monitor or search a control region for control information according to one or more search space sets, and each search space set may include one or more control channel candidates at one or more aggregation levels arranged in a cascaded manner. The aggregation level for a control channel candidate may refer to the number of control channel resources (e.g., control channel elements (CCEs)) associated with the coded information for a control information format having a given payload size. The search space sets may include a common search space set configured for transmitting control information to multiple UEs 115 and a UE-specific search space set for transmitting control information to a specific UE 115 .

[0041] Each base station 105 can provide communication coverage via one or more cells (e.g., macro cells, small cells, hot spots or other types of cells, or any combination thereof). The term "cell" can refer to a logical communication entity used to communicate with the base station 105 (e.g., on a carrier), and can be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID) or other identifier) ​​for distinguishing adjacent cells. In some examples, a cell can also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) on which a logical communication entity operates. Depending on various factors (such as the capabilities of the base station 105), the range of such a cell can range from a smaller area (e.g., a structure, a subset of a structure) to a larger area. For example, a cell can be or include a building, a subset of a building, or an external space between or overlapping geographic coverage areas 110, as well as other examples.

[0042] A macro cell typically covers a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access by a UE 115 having a service subscription with a network provider that supports the macro cell. A small cell may be associated with a lower power base station 105 than a macro cell, and the small cell may operate in the same or different (e.g., licensed, unlicensed) frequency band as the macro cell. A small cell may provide unrestricted access to a UE 115 having a service subscription with a network provider, or may provide restricted access to a UE 115 associated with a small cell (e.g., a UE 115 in a closed subscriber group (CSG), a UE 115 associated with a user in a residence or office). A base station 105 may support one or more cells, and may also support the use of one or more component carriers to communicate on one or more cells.

[0043] 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 to different types of devices.

[0044] In some examples, the base stations 105 may be mobile and, therefore, provide communication coverage for mobile geographic coverage areas 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, overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of base stations 105 provide coverage for respective geographic coverage areas 110 using the same or different radio access technologies.

[0045] The wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication, or various combinations thereof. For example, the wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC) or mission-critical communication. UE115 can be designed to support ultra-reliable, low-latency or critical functions (e.g., mission-critical functions). Ultra-reliable communication can include private communication or group communication, and can 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 can include prioritization of services, and mission-critical services can be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission-critical, and ultra-reliable low-latency can be used interchangeably in this article.

[0046] In some examples, UE 115 is able to communicate directly with other UE 115 on 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 communication may be within a 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 the base station 105 or otherwise unable to receive transmissions from the base station 105. In some examples, groups of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system, wherein each UE 115 transmits to each other UE 115 in the group. In some examples, the base station 105 facilitates scheduling of resources for D2D communication. In other cases, D2D communication is performed between UEs 115 without involving the base station 105.

[0047] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connection, and other access, routing or mobility functions. The core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), which may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function unit (AMF)) for managing access and mobility and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function unit (UPF)) for routing packets to an external network or interconnecting to an external network. The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management for UE 115 served by a base station 105 associated with the core network 130. User IP packets may be transmitted through a user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to a network operator IP service 150. Operator IP services 150 may include access to the Internet, an intranet, an IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0048] Some of the network devices (e.g., base stations 105) may include subcomponents such as access network entities 140, which may be examples of access node controllers (ANCs). Each access network entity 140 may communicate with the UE 115 through one or more other access network transport entities 145 (which may be referred to as radio heads, smart radio heads, or transmit / receive points (TRPs)). Each access network transport entity 145 may include one or more antenna panels. In some configurations, the 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 merged into a single network device (e.g., base station 105).

[0049] The wireless communication system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Typically, the region from 300 MHz to 3 GHz is referred to as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features, but the waves may be sufficient to penetrate structures for macro cells to provide service to UEs 115 located indoors. Transmissions using UHF waves may be associated with smaller antennas and shorter distances (e.g., less than 100 kilometers) than transmissions using smaller frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0050] The wireless communication system 100 can utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 can employ license assisted access (LAA), LTE unlicensed (LTE-U) wireless access technology, or NR technology in an unlicensed band (such as the 5 GHz industrial, scientific, and medical (ISM) band). When operating in an unlicensed radio frequency spectrum band, devices (such as base stations 105 and UEs 115) can employ carrier sensing for conflict detection and avoidance. In some examples, operations in unlicensed bands can be based on a carrier aggregation configuration in combination with component carriers operating in a licensed band (e.g., LAA). Operations in unlicensed spectrum can include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, as well as other examples.

[0051] The base station 105 or UE 115 may be equipped with multiple antennas, which may be used to employ technologies such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of the base station 105 or 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, the antennas or antenna arrays associated with the base station 105 may be located at different geographical locations. The base station 105 may have an antenna array having a number of rows and columns of antenna ports that the base station 105 may use to support beamforming for communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals sent via the antenna ports.

[0052] The base station 105 or UE 115 can use MIMO communication to exploit multipath signal propagation and improve spectral efficiency by sending or receiving multiple signals via different spatial layers. Such a technology may be referred to as spatial multiplexing. For example, a transmitting device may send multiple signals via different antennas or different combinations of antennas. Similarly, a receiving device may receive multiple signals via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers may be associated with different antenna ports for channel measurement and reporting. MIMO technology includes single-user MIMO (SU-MIMO) (where multiple spatial layers are sent to the same receiving device) and multi-user MIMO (MU-MIMO) (where multiple spatial layers are sent to multiple devices).

[0053] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting device or a receiving device (e.g., a base station 105, a UE 115) to form or direct an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming can be achieved by combining signals transmitted via antenna elements of an antenna array so that some signals propagating in a specific orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals transmitted via antenna elements may include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to signals carried via antenna elements associated with the device. Adjustments associated with each of the antenna elements may be defined by a set of beamforming weights associated with a specific orientation (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other orientation).

[0054] As part of the beamforming operation, the base station 105 or the UE 115 may use beam scanning techniques. For example, the base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communications with the UE 115. The base station 105 may send some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) multiple times in different directions. For example, the base station 105 may send signals based on different sets of beamforming weights associated with different transmission directions. Transmissions in different beam directions may be used (e.g., by a transmitting device (such as the base station 105) or by a receiving device (such as the UE 115)) to identify a beam direction for subsequent transmission or reception by the base station 105.

[0055] Base station 105 may transmit some signals (e.g., data signals associated with a particular receiving device (e.g., UE 115)) in a single beam direction (e.g., a direction associated with the receiving device). In some examples, the beam direction associated with transmission along the single beam direction may be determined based on signals transmitted in one or more beam directions. For example, UE 115 may receive one or more of the signals transmitted by base station 105 in different directions and may report to base station 105 an indication of the signal received by UE 115 having the highest signal quality or otherwise acceptable signal quality.

[0056] In some examples, transmissions by a device (e.g., by a base station 105 or a UE 115) may be performed using multiple beam directions, and the device may generate a combined beam for transmission (e.g., from the base station 105 to the UE 115) using a combination of digital precoding or radio frequency beamforming. The UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across the system bandwidth or one or more subbands. The base station 105 may send reference signals (e.g., cell-specific reference signals (CRS), channel state information reference signals (CSI-RS)) that may or may not be precoded. The UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type of codebook, a linear combination type of codebook, a port selection type of codebook). Although these techniques are described with reference to signals sent by base station 105 in one or more directions, UE 115 may employ similar techniques to send signals multiple times in different directions (e.g., to identify a beam direction for subsequent transmission or reception by UE 115) or to send signals in a single direction (e.g., to send data to a receiving device).

[0057] When receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from the base station 105, the receiving device (e.g., UE 115) can try multiple reception configurations (e.g., directional listening). For example, the receiving device can try multiple reception directions by receiving via different antenna subarrays, by processing the received signals according to different antenna subarrays, by receiving according to different reception beamforming weight sets applied to the signals received at multiple antenna elements of the antenna array (e.g., different directional listening weight sets), or by processing the received signals according to different reception beamforming weight sets applied to the signals received at multiple antenna elements of the antenna array (any of the above operations may be referred to as "listening" according to different reception configurations or reception directions). In some examples, the receiving device can use a single reception configuration to receive along a single beam direction (e.g., when receiving a data signal). A single receive configuration may be aligned on a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have the highest signal strength, the highest signal-to-noise ratio (SNR), or otherwise acceptable signal quality based on listening according to multiple beam directions).

[0058] UE 115 and base station 105 can support retransmission of data to increase the possibility that the data is successfully received. Hybrid automatic repeat request (HARQ) feedback is a technology for increasing the possibility that data is correctly received on communication link 125. HARQ can include a combination of error detection (e.g., using cyclic redundancy check (CRC)), forward error correction (FEC) and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve the throughput at the MAC layer under poor radio conditions (e.g., low signal and noise conditions). In some examples, the device can support the same time slot HARQ feedback, wherein the device can provide HARQ feedback for data received in the previous symbol in the time slot in a specific time slot. In other cases, the device can provide HARQ feedback in subsequent time slots or according to some other time interval.

[0059] A UE 115 and a base station of a wireless communication system 100 may support communications that enable efficient post-call service recovery in the context of a dual SIM UE 115. In particular, the wireless communication system 100 may support communications that enable the UE 115 to perform (e.g., initiate or restart) a network discovery process (e.g., a radio access technology acquisition process) associated with a first subscription supported by the UE 115 after termination of a call performed by a second subscription supported by the UE 115. The network discovery process may prioritize higher priority radio access technologies (e.g., NR) over lower priority radio access technologies (e.g., LTE, 3G, 2G). By initiating (or restarting) the network discovery process after call termination, the techniques described herein may facilitate fast and efficient NR service recovery for the UE 115 and prevent delays associated with NR service recovery experienced by some wireless communication systems.

[0060] For example, UE 115 may be an example of a dual SIM UE 115 or a multi-SIM UE 115. For example, UE 115a may include a first SIM and a second SIM. The first SIM may provide a first subscription, and the second SIM may provide a second subscription. UE 115-a may communicate with a first communication network via a first subscription, and may communicate with a second communication network via a second subscription simultaneously or concurrently. In some cases, each network may be supported by a different base station 105, or each network may be supported by the same base station 105, or a combination thereof. For example, a base station 105 of a wireless communication system 100 may support a 5G network, an LTE network, or both. In some cases, a network may refer to a cell. Thus, a base station 105 may support different cells of the same or different networks. Since UE 115 is configured with two subscriptions, UE 115 may support communication with two base stations 105 (e.g., two networks) at the same time. For example, UE 115 may communicate with a base station 105-a associated with a first subscription, and may communicate with a base station 105-b associated with a second subscription.

[0061] In some aspects, UE 115 may establish a first wireless connection associated with a first subscription using a first wireless access technology. For example, UE 115 may establish a first wireless connection with a first cell (e.g., a first base station 105-a) associated with the first subscription. The first cell may be associated with a first wireless access technology (such as an NR technology) (e.g., an NR cell). UE 115 may additionally establish a second wireless connection associated with a second subscription using a second wireless access technology. For example, UE 115 may establish a second wireless connection with a second cell (e.g., a second base station 105-b) associated with a second subscription. The second cell may be associated with a second wireless access technology (such as an LTE technology) (e.g., an LTE cell). In some aspects, the first subscription and the second subscription supported by UE 115 may share common RF hardware resources (e.g., a common modem), common communication resources (e.g., common time resources, common frequency resources), or both.

[0062] Continuing with the same example, UE 115 may perform a call on a second wireless connection associated with a second subscription. For example, UE 115 may perform a voice call (e.g., a VoLTE call, a CSFB call) with an LTE cell (e.g., a second base station 105-b) supported by the second subscription. The voice call may utilize common communication resources used by the first and second subscriptions, and may therefore result in a loss of a first wireless connection associated with the first subscription (e.g., a loss of a first wireless connection with the first base station 105-a). UE 115 may determine the termination of the voice call, and may initiate (or restart) a network discovery process (e.g., a radio access technology acquisition process) based on the termination of the voice call (e.g., after the termination of the voice call).

[0063] In some aspects, the network discovery process may prioritize higher priority radio access technologies (e.g., NR) over lower priority radio access technologies (e.g., LTE, 3G, 2G). For example, the UE 115 may first perform a network discovery process using a first radio access technology (e.g., NR) and may cycle (e.g., switch) through lower priority radio access technologies (e.g., LTE, 3G, 2G) if an attempt to establish a higher priority connection is unsuccessful. By initiating (or restarting) a network discovery process after termination of a voice call, the techniques described herein may enable the UE 115 to quickly and efficiently reestablish a NR connection in order to quickly resume NR service after a voice call.

[0064] Figure 2 An example of a wireless communication system 200 that supports techniques for post-call service recovery in a dual SIM user device according to aspects of the present disclosure is shown. In some examples, the wireless communication system 200 can implement aspects of the wireless communication system 100. The wireless communication system 200 can include a UE 115-a, a first base station 105-a, and a second base station 105-b, which can be as described with reference to Figure 1 Examples of UE 115 and base station 105 are described.

[0065] UE 115a may communicate with a first base station 105-a using a communication link 205-a, which may be an example of an NR link (e.g., a 5G link) between UE 115-a and the first base station 105-a. Similarly, UE 115-a may communicate with a second base station 105-b using a communication link 205-b, which may be an example of an LTE link (e.g., a 4G link) between UE 115-a and the second base station 105-b. In some cases, communication links 205-a, 205-b may include examples of access links (e.g., Uu links). Communication links 205-a, 205-b may include bidirectional links that include both uplink and downlink communications. For example, UE 115-a may use the first communication link 205-a to send an uplink signal (such as an uplink control signal or an uplink data signal) to the first base station 105-a, and the first base station 105-a may use the communication link 205-a to send a downlink signal (such as a downlink control signal or a downlink data signal) to UE 115-a. As another example, UE 115-a may use the second communication link 205-b to send an uplink signal (such as an uplink control signal or an uplink data signal) to the second base station 105-b, and the second base station 105-b may use the communication link 205-b to send a downlink signal (such as a downlink control signal or a downlink data signal) to UE 115-a.

[0066] The first base station 105-a and the second base station 105-b can communicate with each other via a communication link 205-c. In some cases, the communication link 205-c may include an example of a link (e.g., an Xn link) between two base stations. In some cases, the first base station 105-a and the second base station 105-b may be co-located. The communication link 205-c may include a bidirectional link. In some aspects, the first base station 105-a and the second base station 105-b may be associated with one or more cells. For example, the first base station 105-a may be associated with a first cell, and the second base station 105-b may be associated with a second cell different from the first cell. For example, the first base station 105-a may be associated with an NR cell, and the second base station 105-b may be associated with an LTE cell. In some aspects, the first base station 105-a or the second base station 105-b (or both) may facilitate communication between the UE 115-a and other corresponding base stations 105-a, 105-b. For example, when establishing a connection with a cell supported by UE 115-a via communication link 205-a, the first base station 105-a can perform communications with UE 115-a to facilitate establishing a connection between UE 115-a and a cell supported by the second base station 105-b.

[0067] In addition, in some aspects, the first base station 105-a and the second base station 105-b can be associated with one or more subscriptions supported by the UE 115-a. For example, the UE 115-a can include a dual SIM UE 115-a that supports a first subscription and a second subscription. In this example, the first base station 105-a can be associated with the first subscription (e.g., supports the first subscription), and the second base station 105-b can be associated with the second subscription (e.g., supports the second subscription).

[0068] In some aspects, the UE 115-a and base stations 105-a and 105-b of the wireless communication system 200 can support communications that enable efficient post-call service recovery in the context of a dual SIM UE 115-a. In particular, the wireless communication system 200 can support communications that enable the dual SIM UE 115-a to perform (e.g., initiate or restart) a network discovery process (e.g., a radio access technology acquisition process) associated with a first subscription supported by the UE 115-a after termination of a call performed by a second subscription supported by the UE 115-a. The network discovery process can prioritize higher priority radio access technologies (e.g., NR) over lower priority radio access technologies (e.g., LTE, 3G, 2G). By initiating (or restarting) the network discovery process after a call is terminated, the techniques described herein can facilitate fast and efficient NR service recovery for the UE 115-a and prevent delays associated with NR service recovery experienced by some other wireless communication systems.

[0069] For example, UE 115-a may include a dual SIM UE 115-a or a multi-SIM UE 115-a that supports two or more subscriptions. UE 115-a may establish a first wireless connection associated with a first subscription supported by UE 115-a. In some cases, UE 115-a may use a first radio access technology (e.g., NR, 5G) to establish a first wireless connection associated with the first subscription. In some aspects, UE 115-a may establish a first wireless connection with a first cell supported by a first base station 105-a. For example, the first base station 105-a may support an NR cell, and UE 115-a may use a first radio access technology (e.g., NR, 5G) to establish a first wireless connection associated with the first subscription.

[0070] In some aspects, UE 115-a may establish a first wireless connection associated with a first subscription (e.g., a first wireless link with a first base station 105-a) while operating in a standalone operating mode. For example, UE 115-a may establish a first wireless connection using a first wireless access technology while in a standalone operating mode with respect to a first subscription. In some aspects, UE 115-a may establish a first wireless connection with a first cell associated with base station 105-a by performing an attachment procedure. For example, UE 115-a may send an attachment request to base station 105-a via communication link 205-a, and base station 105-a may send an attachment confirmation to UE 115-a via communication link 205-a in response to the attachment request.

[0071] UE 115-a may additionally establish a second wireless connection associated with a second subscription supported by UE 115-a. In some cases, UE 115-a may use a second wireless access technology (e.g., LTE, 4G) to establish a second wireless connection associated with the second subscription. In some aspects, UE 115-a may establish a second wireless connection with a second cell supported by a second base station 105-b. For example, the second base station 105-b may support an LTE cell, and UE 115-a may use a second wireless access technology (e.g., LTE, 4G) to establish a second wireless connection associated with the second subscription. In some aspects, UE 115a may establish a second wireless connection with a second cell associated with the second base station 105-b by performing an attachment process. For example, UE 115-a may send an attachment request to base station 105-b via communication link 205-b, and base station 105-b may send an attachment confirmation to UE 115-b via communication link 206-b in response to the attachment request.

[0072] In some aspects, the first subscription and the second subscription supported by UE 115-a can share the common RF hardware resources of UE 115-a. In addition or alternatively, the first subscription and the second subscription supported by UE 115-a can share the common communication resources (e.g., time resources, frequency resources) used to communicate on the corresponding wireless connection. For example, UE 115-a can communicate on the first wireless connection via a set of communication resources based on establishing the first wireless connection. In addition, UE 115-a can communicate on the second wireless connection via a set of communication resources based on establishing the second wireless connection.

[0073] In some aspects, UE 115-a may perform (e.g., set up) a protocol data unit (PDU) session on a first wireless connection. UE 115-a may perform a PDU session on a first wireless connection with a first cell (e.g., base station 105-a). In some aspects, UE 115-a may perform a PDU session via a first subscription. For example, UE 115-a may perform a PDU session with the first cell to access a network (e.g., the Internet) via the first subscription. In some aspects, UE 115-a may perform a PDU session using a common set of communication resources utilized by the first subscription and the second subscription.

[0074] UE 115-a may perform a call 210 (e.g., a voice call) on a second wireless connection associated with a second subscription. In this regard, UE 115-a may perform call 210 with a second cell (e.g., base station 105-b). The performed call 210 may include, but is not limited to, a VoLTE call, a CSFB call, etc. In some aspects, the call 210 performed on the second wireless connection (e.g., communication link 205-b) may be performed using a common set of resources (e.g., common RF hardware resources, common time / frequency resources) utilized by the first subscription and the second subscription.

[0075] In some aspects, UE 115-a can identify the loss of a first wireless connection associated with a first subscription. In this regard, UE 115-a can identify the loss of a first wireless connection associated with a first cell (e.g., base station 105-a). In some cases, UE 115-a can identify the loss of the first wireless connection based on performing a call 210 on a second wireless connection. For example, the call 210 performed via the second subscription can be performed using a common set of communication resources utilized by the first subscription and the second subscription, and thus the first wireless connection associated with the first subscription and the first cell can be terminated or otherwise interrupted. In some aspects, UE 115-a can identify the loss of the first wireless connection based on messaging, signaling, or other indications exchanged between two subscriptions supported by UE 115-a.

[0076] UE 115-a may initiate a network discovery process (e.g., a radio access technology acquisition process) associated with the first subscription. In some aspects, UE 115-a may initiate a network discovery process associated with the first subscription using the first radio access technology based on identifying a loss of the first radio connection. For example, UE 115-a may initiate a network discovery process using NR technology based on identifying a loss of the first radio connection. In some aspects, UE 115-a may initiate a network discovery process prior to termination of call 210 on the second radio connection.

[0077] In some aspects, UE 115-a may perform (e.g., initiate) a network discovery process using a first radio access technology (e.g., NR, 5G). In this regard, UE 115-s may prioritize the first radio access technology (e.g., NR, 5G) over lower priority radio access technologies (e.g., LTE, 3G, 3G) when performing the network discovery process. For example, where the first radio access technology includes NR technology and the second radio access technology includes LTE technology, UE 115-a may prioritize NR technology over LTE technology, and thus, may attempt to establish an NR radio connection via the network discovery process before attempting to establish an LTE radio connection via the network discovery process.

[0078] In some aspects, if the network discovery process fails to establish a connection using the first radio access technology, the UE 115-a may perform a network discovery process using the lower priority radio access technology to establish a connection associated with one or more of the lower priority radio access technologies. In some aspects, the UE 115-a may be configured to cycle from the first radio access technology to the lower priority radio access technology based on an attach attempt counter, a timer, or both.

[0079] For example, UE 115-a may initiate network discovery using a first radio access technology (e.g., NR technology) based on identifying the loss of a first radio connection. When initiating the network discovery process, UE 115-a may initiate (e.g., start) an attachment attempt counter, a timer, or both. When UE 115-a performs a network discovery process using NR technology, UE 115-a may increment the attachment attempt counter each time the attachment process is attempted. In addition, the timer may run when UE 115-a performs a network discovery process using NR technology. In some cases, UE 115-a may determine that the attachment attempt counter satisfies a threshold counter, the timer satisfies a threshold duration, or both. In some aspects, the attachment attempt counter may satisfy the threshold counter when the attachment attempt counter is equal to or greater than the threshold counter. Similarly, the timer may satisfy the threshold duration when the timer runs for at least the threshold duration. Upon determining that the attach attempt counter satisfies a threshold counter, the timer satisfies a threshold duration, or both, UE 115-a may switch to a second radio access technology (eg, LTE) and perform a network discovery process using the second radio access technology.

[0080] In this example, UE 115-a may cycle (e.g., switch) from performing a network discovery process using a first radio access technology (e.g., NR) to a second radio access technology (e.g., LTE) based on an attach attempt counter satisfying a threshold counter, a timer satisfying a threshold duration, or both. In some aspects, UE 115-a may restart (e.g., reset) an attach attempt counter, a timer, or both based on performing a network discovery process using the second radio access technology. In a similar manner, UE 115-a may cycle (e.g., switch) from performing a network discovery process using a second radio access technology (e.g., LTE) to a third radio access technology (e.g., 3G) and / or a fourth radio access technology (e.g., 2G) based on an attach attempt counter satisfying a threshold counter, a timer satisfying a threshold timer duration, or both.

[0081] The attach attempt counter and / or timer may be pre-configured by the UE 115-a, signaled to the UE 115-a from the base station 105 via configuration signaling, or both. In some aspects, various radio access technologies may display the same or different attach attempt counters and / or timers. For example, a first timer associated with a first radio access technology (e.g., NR) may be longer than a second timer associated with a second radio access technology (e.g., LTE), thereby allowing the UE 115-a to establish an NR connection for more time than it allows to establish an LTE connection.

[0082] In some aspects, UE 115-a may terminate a call 210 (e.g., a voice call) performed on the second radio connection. For example, UE 115-a may terminate call 210 performed on a second radio connection with a second cell via a second subscription. In some aspects, terminating call 210 may release a common set of communication resources used by the first subscription and the second subscription. In some aspects, UE 115-a may be configured to determine termination of call 210 on the second radio connection.

[0083] UE 115-a may perform (e.g., initiate or restart) a network discovery procedure based on identifying a loss of the first connection, a termination of call 210, or any combination thereof. For example, UE 115-a may perform a network discovery procedure associated with a first subscription using a first radio access technology based on identifying a loss of the first connection and a termination of call 210 on a second radio connection.

[0084] In some aspects, the UE 115-a may be said to initiate or restart the network discovery process after the termination of the call 210 based on whether the UE 115-a initiated the network discovery process before the termination of the call 210. For example, in a case where the UE 115-a did not initiate the network discovery process before the termination of the call 210 on the second radio connection, the UE 115-a may initiate the network discovery process after the termination of the call 210. In contrast, in a case where the UE 115-a initiated the network discovery process before the termination of the call 210 on the second radio connection, the UE 115-a may restart (e.g., restart) the network discovery process after the termination of the call 210. In a case where the UE 115-a restarts (e.g., restarts, resets) the network discovery process after the termination of the call 210, the UE 115-a may restart the network discovery process to perform the network discovery process using the first radio access technology (e.g., NR). Additionally, in the event that UE 115-a restarts the network discovery process after termination of call 210, UE 115-a may restart (e.g., reset) an attach attempt counter, a timer, or both associated with the network discovery process. In this regard, UE 115-a may reset the attach attempt counter, the timer, or both based on restarting the network discovery process after termination of call 210.

[0085] As previously mentioned herein, when the network discovery process is initiated (or restarted) after termination of call 210, UE 115-a may cycle (e.g., switch) between various radio access technologies while performing the network discovery process based on an attach attempt counter satisfying a threshold counter, a timer satisfying a threshold timer duration, or both. In this regard, UE 115-a may first perform a network discovery process using a first radio access technology (e.g., NR), and may subsequently perform a network discovery process using a lower priority radio access technology (e.g., LTE, 3G, 2G) if an attempt to establish a higher priority connection is unsuccessful.

[0086] In some aspects, UE 115-a can establish a wireless connection associated with the first subscription. In some cases, UE 115-a can establish a third wireless connection associated with the first subscription using a first wireless access technology (e.g., NR, 5G). For example, UE 115-a can establish a wireless connection with a first cell supported by a first base station 105-a using the first wireless access technology. As another example, UE 115-a can establish a wireless connection with an additional cell supported by the first base station 105-a or another base station using the first wireless access technology.

[0087] In the event that UE 115-a fails to establish a connection via a network discovery process using a first radio access technology, UE 115-a may establish a lower priority connection using a second radio access technology (e.g., LTE) or another lower priority radio access technology (e.g., 3G, 2G). In such a case, UE 115-a may perform an attachment process using the first radio access technology after establishing the lower priority connection. However, by initiating (or restarting) the network discovery process after termination of call 210, UE 115-a may significantly increase the probability of establishing a connection using the first radio access technology before establishing a connection using a lower priority radio access technology.

[0088] Thus, initiating (or restarting) the network discovery process using the first radio access technology (e.g., NR) at 340 may enable UE 115-b to establish a connection using a higher priority radio access technology (e.g., NR) before establishing a connection using a lower priority radio access technology (e.g., LTE, 3G, 2G). By preventing UE 115-a from first establishing a connection using a lower priority radio access technology (e.g., LTE, 3G, 2G), the techniques described herein may prevent delays in NR service recovery, thereby improving call 210 and resulting in an improved user experience.

[0089] Figure 3 An example of a process flow 300 supporting techniques for post-call service recovery in a dual SIM user device according to aspects of the present disclosure is shown. In some examples, the process flow 300 can implement aspects of the wireless communication system 100 or 200. For example, the process flow 300 can show establishing a first wireless connection with a first cell associated with a first subscription, establishing a second wireless connection with a second cell associated with a second subscription, performing a call on the second wireless connection, and performing a network discovery process associated with the first subscription based on termination of the call, as described with reference to Figure 1-2 Described.

[0090] In some cases, process flow 300 may include UE 115-b, base station 105-c, and base station 105-d, which may be examples of corresponding devices as described herein. Figure 3 The UE 115-b shown in FIG. 1 may be Figure 2 . Similarly, Figure 3 The base stations 105-c and 105-d shown in FIG. Figure 2Thus, in some cases, base station 105-c may support cells associated with a first wireless access technology (e.g., NR cells), and base station 105-d may support cells associated with a second wireless access technology (e.g., LTE cells).

[0091] In some examples, the operations shown in process flow 300 can be performed by hardware (e.g., including circuits, processing blocks, logic components, and other components), code executed by a processor (e.g., software or firmware), or any combination thereof. The following alternative examples can be implemented, in which some steps can be performed in a different order than described or not performed at all. In some cases, the steps can include additional features not mentioned below, or additional steps can be added.

[0092] At 305, UE 115-b may establish a first wireless connection associated with a first subscription supported by UE 115-b. In some cases, UE 115-b may establish a first wireless connection associated with the first subscription using a first wireless access technology (e.g., NR, 5G). In some cases, UE 115-b may establish a first wireless connection with a first cell (e.g., NR cell, 5G cell) associated with the first wireless access technology. In some aspects, UE 115-b may establish a first wireless connection with the first cell while operating in an independent operation mode. For example, UE 115-b may establish a first wireless connection using a first wireless access technology while in an independent operation mode with respect to the first subscription. In some aspects, UE 115-b may establish a first wireless connection with a first cell associated with base station 105-c by performing an attachment process. For example, UE 115-b may send an attachment request to base station 105-c, and base station 105-c may send an attachment confirmation to UE 115-b in response to the attachment request.

[0093] At 310, UE 115-b may establish a second wireless connection associated with a second subscription supported by UE 115-b. In some cases, UE 115-b may establish a second wireless connection associated with the second subscription using a second wireless access technology (e.g., LTE, 4G). In some cases, UE 115-b may establish a second wireless connection with a second cell (e.g., LTE cell, 4G cell) associated with the second wireless access technology. In some aspects, UE 115-b may establish a second wireless connection with a second cell associated with base station 105-d by performing an attachment process. For example, UE 115-b may send an attachment request to base station 105-d, and base station 105-d may send an attachment confirmation to UE 115-b in response to the attachment request.

[0094] In some aspects, the first subscription and the second subscription supported by UE 115-b may share common hardware resources of UE 115-b. Additionally or alternatively, the first subscription and the second subscription supported by UE 115-b may share common communication resources (e.g., time resources, frequency resources) to communicate on corresponding wireless connections. For example, UE 115-b may communicate with a first cell (e.g., base station 105-c) associated with the first subscription on the first wireless connection via a set of communication resources based on establishing a first wireless connection at 305. Additionally, UE 115-b may communicate with a second cell (e.g., base station 105-d) associated with the second subscription on the second wireless connection via a set of communication resources based on establishing a second wireless connection at 310.

[0095] At 315, UE 115-b may perform (e.g., set up) a PDU session on the first wireless connection. UE 115-b may perform the PDU session on the first wireless connection with the first cell (e.g., base station 105-c). In some aspects, UE 115-b may perform the PDU session via the first subscription. For example, UE 115-b may perform the PDU session with the first cell to access a network (e.g., the Internet) via the first subscription. In some aspects, UE 115b may perform the PDU session using a common set of communication resources utilized by the first subscription and the second subscription.

[0096] At 320, UE 115b may perform a call on a second radio connection associated with the second subscription. In this regard, UE 115-b may perform a call with a second cell (e.g., base station 105-d). UE 115-b may perform a call at 320 based on establishing the second radio connection at 310. The call performed at 320 may include, but is not limited to, a VoLTE call, a CSFB call, etc. In some aspects, the call (e.g., a voice call) performed on the second radio connection may be performed using a common set of resources used by the first subscription and the second subscription.

[0097] At 325, UE 115-b may identify a loss of a first wireless connection associated with a first subscription. In this regard, UE 115-b may identify a loss of a first wireless connection associated with a first cell (e.g., base station 105-c). In some cases, UE 115-b may identify a loss of the first wireless connection based on performing a call on a second wireless connection. For example, the call performed via the second subscription at 320 may be performed using a common set of communication resources utilized by the first subscription and the second subscription, and thus the first wireless connection associated with the first subscription and the first cell may be terminated or otherwise interrupted. In some aspects, UE 115-b may identify a loss of the first wireless connection based on messaging, signaling, or other indications exchanged between two subscriptions supported by UE 115-b.

[0098] At 330, the UE 115-b may initiate a network discovery procedure (e.g., a radio access technology acquisition procedure) associated with the first subscription. In some aspects, the UE 115-b may initiate a network discovery procedure associated with the first subscription using the first radio access technology based on identifying a loss of the first radio connection at 325. For example, the UE 115-b may initiate a network discovery procedure using an NR technology based on identifying a loss of the first radio connection at 325. In some aspects, the UE 115-b may initiate the network discovery procedure at 330 prior to termination of the call on the second radio connection.

[0099] In some aspects, UE 115-b may perform (e.g., initiate) a network discovery process using a first radio access technology (e.g., NR, 5G). In this regard, UE 115-b may prioritize the first radio access technology (e.g., NR, 5G) over lower priority radio access technologies (e.g., LTE, 3G, 3G) when performing the network discovery process. For example, where the first radio access technology includes NR technology and the second radio access technology includes LTE technology, UE 115-b may prioritize NR technology over LTE technology, and thus, may attempt to establish an NR radio connection via the network discovery process before attempting to establish an LTE radio connection via the network discovery process.

[0100] In some aspects, if the network discovery process fails to establish a connection using the first radio access technology, the UE 115-b may perform a network discovery process using a lower priority radio access technology to establish a connection associated with one or more lower priority radio access technologies. In some aspects, the UE 115-b may be configured to cycle from the first radio access technology to the lower priority radio access technology based on an attach attempt counter, a timer, or both.

[0101] For example, UE 115-b may use a first radio access technology (e.g., NR technology) to initiate a network discovery process at 330. When initiating the network discovery process, UE 115-b may start an attachment attempt counter, a timer, or both. When UE 115-b uses NR technology to perform a network discovery process, UE 115-b may increment the attachment attempt counter each time the attachment process is attempted. In addition, the timer may run when UE 115-b performs a network discovery process using NR technology. In some cases, UE 115-b may determine that the attachment attempt counter satisfies a threshold counter, the timer satisfies a threshold duration, or both. In some aspects, the attachment attempt counter may satisfy the threshold counter when the attachment attempt counter is equal to or greater than the threshold counter. Similarly, the timer may satisfy the threshold duration when the timer runs for at least the threshold duration. Upon determining that the attach attempt counter satisfies a threshold counter, the timer satisfies a threshold duration, or both, UE 115-b may switch to a second radio access technology (eg, LTE) and perform a network discovery process using the second radio access technology.

[0102] In this example, UE 115-b may cycle (e.g., switch) from performing a network discovery process using a first radio access technology (e.g., NR) to a second radio access technology (e.g., LTE) based on an attach attempt counter satisfying a threshold counter, a timer satisfying a threshold duration, or both. In some aspects, UE 115-b may restart (e.g., reset) an attach attempt counter, a timer, or both based on performing a network discovery process using the second radio access technology. In a similar manner, UE 115-b may cycle (e.g., switch) from performing a network discovery process using a second radio access technology (e.g., LTE) to a third radio access technology (e.g., 3G, 2G) based on an attach attempt counter satisfying a threshold counter, a timer satisfying a threshold timer duration, or both.

[0103] The attach attempt counter and / or timer may be pre-configured by the UE 115-b, signaled to the UE 115-b via configuration signaling, or both. In some aspects, various radio access technologies may display the same or different attach attempt counters and / or timers. For example, a first timer associated with a first radio access technology (e.g., NR) may be longer than a second timer associated with a second radio access technology (e.g., LTE), thereby allowing the UE 115-b to establish an NR connection for more time than it allows to establish an LTE connection.

[0104] At 335, UE 115-b may terminate the call (e.g., voice call) performed on the second radio connection. For example, UE 115-b may terminate the call performed on the second radio connection with the second cell via the second subscription. In some aspects, terminating the call at 335 may release a common set of communication resources used by the first subscription and the second subscription. In some aspects, UE 115-b may be configured to determine termination of the call at 335.

[0105] At 340, the UE 115-b may perform (e.g., initiate or restart) a network discovery procedure. In some aspects, the UE 115-b may perform the network discovery procedure based on identifying the loss of the first connection at 325, the termination of the call at 335, or any combination thereof. For example, the UE 115-b may perform a network discovery procedure associated with the first subscription using the first radio access technology based on identifying the loss of the first connection at 325 and the termination of the call at 335.

[0106] The UE 115-b may initiate or restart the network discovery process at 340 based on whether the UE 115-b initiated the network discovery process at 330. For example, in the case where the UE 115-b did not initiate the network discovery process at 330, the UE 115-b may initiate the network discovery process at 340. In contrast, in the case where the UE 115-b initiated the network discovery process at 330, the UE 115-b may restart (e.g., restart) the network discovery process at 340. In the case where the UE 115-b restarts (e.g., restarts, resets) the network discovery process at 340, the UE 115-b may restart the network discovery process to perform the network discovery process using the first radio access technology (e.g., NR). In addition, in the case where the UE 115-b restarts the network discovery process at 340, the UE 115-b may restart (e.g., reset) an attach attempt counter, a timer, or both associated with the network discovery process. In some aspects, UE 115 - b may reset the attach attempt counter, the timer, or both based on restarting the network discovery process at 340 .

[0107] As previously mentioned herein, when the network discovery process is initiated (or restarted) at 340, the UE 115-b may cycle (e.g., switch) between various radio access technologies while performing the network discovery process based on an attach attempt counter satisfying a threshold counter, a timer satisfying a threshold timer duration, or both. In this regard, the UE 115-b may first perform a network discovery process using a first radio access technology (e.g., NR), and may subsequently perform a network discovery process using a lower priority radio access technology (e.g., LTE, 3G, 2G) if an attempt to establish a higher priority connection is unsuccessful.

[0108] At 345, UE 115-b may establish a third wireless connection associated with the first subscription. In some cases, UE 115-b may establish the third wireless connection associated with the first subscription using the first wireless access technology (e.g., NR, 5G). For example, UE 115-b may establish the third wireless connection associated with the first subscription at 345 based on performing a network discovery process using the first wireless access technology at 340.

[0109] Initiating (or restarting) the network discovery process using the first radio access technology (e.g., NR) at 340 may enable the UE 115-b to establish a connection using a higher priority radio access technology (e.g., NR) before establishing a connection using a lower priority radio access technology (e.g., LTE, 3G, 2G). By preventing the UE 115-b from first establishing a connection using a lower priority radio access technology (e.g., LTE, 3G, 2G), the techniques described herein may prevent delays in NR service recovery, thereby improving calls and resulting in an improved user experience.

[0110] Figure 4 A block diagram 400 of a device 405 supporting techniques for post-call service recovery in a dual SIM user device according to aspects of the present disclosure is shown. 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 communication manager 415, and a transmitter 420. The device 405 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0111] 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 techniques for post-call service recovery in dual SIM user devices, etc.). The information may be communicated to other components of the device 405. The receiver 410 may be a reference Figure 7 Examples of various aspects of transceiver 720 are described. Receiver 410 may utilize a single antenna or a group of antennas.

[0112] The communication manager 415 may perform the following operations: establish a first wireless connection associated with a first subscription using a first wireless access technology; identify a loss of the first wireless connection based on performing a call on the second wireless connection; establish a second wireless connection associated with a second subscription using a second wireless access technology; perform a call on the second wireless connection; and based on the loss of the first wireless connection and the termination of the call on the second wireless connection, perform a network discovery process associated with the first subscription using the first wireless access technology. The communication manager 415 may be an example of aspects of the communication manager 710 described herein.

[0113] The operations performed by the communication manager 415 as described herein may be implemented to achieve one or more potential advantages. For example, performing a network discovery process associated with a first subscription using a first radio access technology (e.g., NR) after termination of a call associated with a second subscription may enable the UE 115 to quickly and efficiently reestablish NR service. In particular, by preventing the UE 115 from first establishing a connection with a lower priority radio access technology (e.g., LTE, 3G, 2G), the communication manager 415 may prevent delays in NR service resumption, thereby improving the call and resulting in an improved user experience for the UE 115.

[0114] Based on performing a network discovery process associated with the first subscription using the first radio access technology (e.g., NR) after termination of the call associated with the second subscription, a processor of UE 115 (e.g., a processor controlling receiver 410, communication manager 415, transmitter 420, etc.) can reduce processing resources used for the attachment process. For example, by establishing an NR connection before establishing an LTE, 3G, or 2G connection, the number of attachment processes can be reduced. Subsequently, the processor of UE 115 can reduce the number of retransmission and signaling resources used by UE 115, thereby correspondingly reducing the number of times the processor boosts processing power and turns on processing units to process uplink transmissions and / or downlink receptions.

[0115] The communication manager 415 or its subcomponents may be implemented in hardware, in 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 communication manager 415 or its subcomponents may be performed by a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (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.

[0116] The communication manager 415 or its subcomponents may be physically located at various locations, including being distributed so that portions of the functions are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the communication manager 415 or its subcomponents may be separate and distinct components. In some examples, according to various aspects of the present disclosure, the communication manager 415 or its subcomponents may be combined with one or more other hardware components (including, but not limited to, input / output (I / O) components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof).

[0117] The transmitter 420 can transmit signals generated by other components of the device 405. In some examples, the transmitter 420 can be co-located with the receiver 410 in a transceiver module. For example, the transmitter 420 can be a reference Figure 7 Examples of aspects of transceiver 720 are described. Transmitter 420 may utilize a single antenna or a group of antennas.

[0118] Figure 5 A block diagram 500 of a device 505 supporting techniques for post-call service recovery in a dual SIM user device according to aspects of the present disclosure is shown. The device 505 may be an example of aspects of the device 405 or UE 115 as described herein. The device 505 may include a receiver 510, a communication manager 515, and a transmitter 540. The device 505 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0119] 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 techniques for post-call service recovery in dual SIM user devices, etc.). The information may be communicated to other components of the device 505. The receiver 510 may be a reference Figure 7 Examples of various aspects of the transceiver 720 are described. The receiver 510 may utilize a single antenna or a group of antennas.

[0120] The communication manager 515 may be an example of aspects of the communication manager 415 as described herein. The communication manager 515 may include a first subscription manager 520, a second subscription manager 525, a call manager 530, and a network discovery process manager 535. The communication manager 515 may be an example of aspects of the communication manager 710 described herein.

[0121] The first subscription manager 520 may establish a first wireless connection associated with the first subscription using a first wireless access technology and identify a loss of the first wireless connection based on performing a call on a second wireless connection. The second subscription manager 525 may establish a second wireless connection associated with the second subscription using a second wireless access technology.

[0122] The call manager 530 may perform the call on the second radio connection.The network discovery process manager 535 may perform a network discovery process associated with the first subscription using the first radio access technology based on the loss of the first radio connection and the termination of the call on the second radio connection.

[0123] The transmitter 540 can transmit signals generated by other components of the device 505. In some examples, the transmitter 540 can be co-located with the receiver 510 in a transceiver module. For example, the transmitter 540 can be a reference Figure 7 Examples of aspects of transceiver 720 are described. Transmitter 540 may utilize a single antenna or a group of antennas.

[0124] Figure 6 A block diagram 600 of a communication manager 605 supporting techniques for post-call service recovery in a dual SIM user device according to aspects of the present disclosure is shown. The communication manager 605 may be an example of aspects of the communication manager 415, the communication manager 515, or the communication manager 710 described herein. The communication manager 605 may include a first subscription manager 610, a second subscription manager 615, a call manager 620, a network discovery process manager 625, an attachment process manager 630, a hardware resource manager 635, a first RAT manager 640, and a second RAT manager 645. Each of these modules may communicate with each other directly or indirectly (e.g., via one or more buses).

[0125] The first subscription manager 610 may establish a first wireless connection associated with the first subscription using a first wireless access technology.

[0126] In some examples, the first subscription manager 610 may identify a loss of the first wireless connection based on performing a call on the second wireless connection. In some examples, the first subscription manager 610 may establish a third wireless connection associated with the first subscription using the first wireless access technology based on performing a network discovery process using the first wireless access technology. In some examples, the first subscription manager 610 may communicate on the first wireless connection associated with the first subscription using the set of communication resources based on establishing the first wireless connection.

[0127] The second subscription manager 615 can establish a second wireless connection associated with the second subscription using the second wireless access technology. In some examples, the second subscription manager 615 can use the communication resource set to perform a call on the second wireless connection, wherein identifying the loss of the first wireless connection is based on performing the call on the second wireless connection using the communication resource set.

[0128] The call manager 620 may perform a call on the second wireless connection. In some examples, performing a call on the second wireless connection includes performing a VOLTE call or a CSFB call.

[0129] The network discovery process manager 625 may perform a network discovery process associated with the first subscription using the first wireless access technology based on the loss of the first wireless connection and the termination of the call on the second wireless connection. In some examples, the network discovery process manager 625 may initiate a network discovery process associated with the first subscription using the first wireless access technology based on the loss of the first wireless connection, wherein the network discovery process is initiated before the termination of the call on the second wireless connection. In some examples, performing the network discovery process based on the loss of the first wireless connection and the termination of the call on the second wireless connection includes: restarting the network discovery process after the termination of the call on the second wireless connection.

[0130] In some examples, the network discovery process manager 625 can start an attach attempt counter, a timer, or both based on initiating the network discovery process. In some examples, the network discovery process manager 625 can perform a network discovery process using the second radio access technology based on the attach attempt counter satisfying a threshold counter, the timer satisfying a threshold duration, or both. In some examples, the network discovery process manager 625 can reset the attach attempt counter, the timer, or both based on restarting the network discovery process after termination of the call on the second radio connection.

[0131] When operating in the standalone operation mode, the attach procedure manager 630 may perform an attach procedure with a cell associated with the first subscription, wherein establishing the first radio connection is based on performing the attach procedure.

[0132] The hardware resource manager 635 may manage radio frequency hardware resources used for communication via the first subscription and the second subscription.

[0133] In some cases, a first radio connection associated with the first subscription is established using a set of radio frequency hardware resources of the UE, and a second radio connection associated with the second subscription is established using a set of radio frequency hardware resources of the UE.

[0134] The first RAT manager 640 may manage communications performed via a first radio access technology (e.g., NR, 5G). In some cases, the first radio access technology includes a new radio technology, a fifth generation (5G) technology, or both. The second RAT manager 645 may manage communications performed via a second radio access technology (e.g., LTE, 4G). In some cases, the second radio access technology includes a long term evolution technology, a fourth generation (4G) technology, or both.

[0135] Figure 7 A diagram of a system 700 including a device 705 supporting techniques for post-call service recovery in a dual SIM user device according to aspects of the present disclosure is shown. The device 705 may be an example of or include a component of a device 405, a device 505, or a UE 115 as described herein. The device 705 may include components for two-way voice and data communications, including components for sending and receiving communications, including a communication manager 710, an I / O controller 715, a transceiver 720, an antenna 725, a memory 730, and a processor 740. These components may be in electronic communication via one or more buses (e.g., a bus 745).

[0136] The communication manager 710 can perform the following operations: use a first wireless access technology to establish a first wireless connection associated with a first subscription; identify the loss of the first wireless connection based on performing a call on the second wireless connection; use a second wireless access technology to establish a second wireless connection associated with a second subscription; perform a call on the second wireless connection; and based on the loss of the first wireless connection and the termination of the call on the second wireless connection, use the first wireless access technology to perform a network discovery process associated with the first subscription.

[0137] I / O controller 715 can manage input and output signals for device 705. I / O controller 715 can also manage peripheral devices that are not integrated into device 705. In some cases, I / O controller 715 can represent a physical connection or port to an external peripheral device. In some cases, I / O controller 715 can utilize a computer such as a , or another known operating system. In other cases, I / O controller 715 may represent or interact with a modem, keyboard, mouse, touch screen, or similar device. In some cases, I / O controller 715 may be implemented as part of a processor. In some cases, a user may interact with device 705 via I / O controller 715 or via hardware components controlled by I / O controller 715.

[0138] The transceiver 720 may communicate bidirectionally 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 bidirectionally with another wireless transceiver. The transceiver 720 may also include a modem for modulating packets and providing the modulated packets to an antenna for transmission, and demodulating packets received from an antenna.

[0139] In some cases, a wireless device may include a single antenna 725. However, in some cases, the device may have more than one antenna 725 that are capable of sending or receiving multiple wireless transmissions simultaneously.

[0140] The memory 730 may include random access memory (RAM) and read-only memory (ROM). The memory 730 may store computer-readable, computer-executable code 735, which includes instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 730 may also contain a basic I / O system (BIOS) and other devices that may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0141] 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, the 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., memory 730) to cause the device 705 to perform various functions (e.g., functions or tasks that support techniques for post-call service recovery in dual SIM user devices).

[0142] The code 735 may include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communications. The code 735 may be stored in a non-transitory computer-readable medium (e.g., system memory or other types 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 the functions described herein.

[0143] Figure 8 A flow chart illustrating a method 800 for supporting techniques for post-call service recovery in a dual SIM user device according to aspects of the present disclosure is shown. The operations of the method 800 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 800 may be implemented by a UE 115 or a component thereof as described herein. Figures 4 to 7 In some examples, the UE may execute an instruction set to control the functional units of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0144] At 805, the UE may establish a first wireless connection associated with a first subscription using a first wireless access technology. 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 as described with reference to Figures 4 to 7 The first subscription manager described is executed.

[0145] At 810, the UE may establish a second wireless connection associated with the second subscription using a second wireless access technology. 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 as described with reference to Figures 4 to 7 The second subscription manager described is executed.

[0146] At 815, the UE may perform a call on the second radio connection. 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 as described with reference to Figures 4 to 7 Describes the call manager to perform.

[0147] At 820, the UE may identify a loss of the first wireless connection based on performing a call on the second wireless connection. The operations of 820 may be performed according to the methods described herein. In some examples, aspects of the operations of 820 may be performed as described with reference to Figures 4 to 7 The first subscription manager described is executed.

[0148] At 825, the UE may perform a network discovery procedure associated with the first subscription using the first radio access technology based on the loss of the first radio connection and the termination of the call on the second radio connection. The operations of 825 may be performed according to the methods described herein. In some examples, aspects of the operations of 825 may be performed as described with reference to Figures 4 to 7 Describes the network discovery process performed by the manager.

[0149] Fig. 9 A flow chart illustrating a method 900 for supporting techniques for post-call service recovery in a dual SIM user device according to aspects of the present disclosure is shown. The operations of the method 900 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 900 may be implemented by a UE 115 or a component thereof as described with reference to Figures 4 to 7In some examples, the UE may execute an instruction set to control the functional units of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0150] At 905, the UE may establish a first wireless connection associated with a first subscription using a first wireless access technology. The operations of 905 may be performed according to the methods described herein. In some examples, aspects of the operations of 905 may be described with reference to Figures 4 to 7 The first subscription manager described is executed.

[0151] At 910, the UE may establish a second wireless connection associated with a second subscription using a second wireless access technology. The operations of 910 may be performed according to the methods described herein. In some examples, aspects of the operations of 910 may be performed as described with reference to Figures 4 to 7 The second subscription manager described is executed.

[0152] At 915, the UE may perform a call on the second radio connection. The operations of 915 may be performed according to the methods described herein. In some examples, aspects of the operations of 915 may be performed as described with reference to Figures 4 to 7 Describes the call manager to perform.

[0153] At 920, the UE may identify a loss of the first wireless connection based on performing a call on the second wireless connection. The operations of 920 may be performed according to the methods described herein. In some examples, aspects of the operations of 920 may be performed as described with reference to Figures 4 to 7 The first subscription manager described is executed.

[0154] At 925, the UE may initiate a network discovery process associated with the first subscription using the first radio access technology based on the loss of the first radio connection, wherein the network discovery process is initiated before the termination of the call on the second radio connection. The operations of 925 may be performed according to the methods described herein. In some examples, aspects of the operations of 925 may be performed as described with reference to Figures 4 to 7 Describes the network discovery process performed by the manager.

[0155] At 930, the UE may restart a network discovery process associated with the first subscription based on the loss of the first radio connection and the termination of the call on the second radio connection to perform a network discovery process using the first radio access technology. The operations of 930 may be performed according to the methods described herein. In some examples, aspects of the operations of 930 may be performed as described with reference to Figures 4 to 7 Describes the network discovery process performed by the manager.

[0156] Fig.10A flow chart illustrating a method 1000 for supporting techniques for post-call service recovery in a dual SIM user device according to aspects of the present disclosure is shown. The operations of the method 1000 may be implemented by a UE 115 or a component thereof as described herein. For example, the operations of the method 1000 may be implemented by a UE 115 or a component thereof as described with reference to Figures 4 to 7 In some examples, the UE may execute an instruction set to control the functional units of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0157] At 1005, the UE may establish a first wireless connection associated with a first subscription using a first wireless access technology. The operations of 1005 may be performed according to the methods described herein. In some examples, aspects of the operations of 1005 may be performed as described with reference to Figures 4 to 7 The first subscription manager described is executed.

[0158] At 1010, the UE may establish a second radio connection associated with a second subscription using a second radio access technology. The operations of 1010 may be performed according to the methods described herein. In some examples, aspects of the operations of 1010 may be performed as described with reference to Figures 4 to 7 The second subscription manager described is executed.

[0159] At 1015, the UE may perform a call on the second radio connection. The operations of 1015 may be performed according to the methods described herein. In some examples, aspects of the operations of 1015 may be performed as described with reference to Figures 4 to 7 Describes the call manager to perform.

[0160] At 1020, the UE may identify a loss of the first radio connection based on performing a call on the second radio connection. The operations of 1020 may be performed according to the methods described herein. In some examples, aspects of the operations of 1020 may be described as described with reference to Figures 4 to 7 The first subscription manager described is executed.

[0161] At 1025, the UE may perform a network discovery procedure associated with the first subscription using the first radio access technology based on the loss of the first radio connection and the termination of the call on the second radio connection. The operations of 1025 may be performed according to the methods described herein. In some examples, aspects of the operations of 1025 may be performed as described with reference to Figures 4 to 7 Describes the network discovery process performed by the manager.

[0162] At 1030, the UE may establish a third wireless connection associated with the first subscription using the first wireless access technology based on performing a network discovery process using the first wireless access technology. The operations of 1030 may be performed according to the methods described herein. In some examples, aspects of the operations of 1030 may be described as described with reference to Figures 4 to 7 The first subscription manager described is executed.

[0163] It should be noted that the methods described herein describe possible implementations, and that the operations and steps may be rearranged or otherwise modified, and other implementations are possible. Furthermore, aspects from two or more methods may be combined.

[0164] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems 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 communication 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, and other systems and radio technologies not explicitly mentioned herein.

[0165] The information and signals described herein may be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0166] The various illustrative blocks and components described in conjunction with the disclosure herein may be implemented or executed using a general purpose processor, DSP, ASIC, CPU, 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 an alternative, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, a combination of one or more microprocessors and a DSP core, or any other such configuration).

[0167] 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 sent through a computer-readable medium as one or more instructions or codes. Other examples and implementations are within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented in software executed by a processor, hardware, firmware, hard wiring, or any combination of these. Features that implement the functions may also be physically located at various locations, including being distributed so that parts of the functions are implemented at different physical locations.

[0168] Computer readable medium includes both non-transitory computer storage medium and communication medium, and communication medium includes any medium that promotes the transmission of computer program from one place to another place.Non-transitory storage medium can be any available medium that can be accessed by general-purpose computer or special-purpose computer.By way of example and not limitation, non-transitory computer readable medium can include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disc storage, disk storage or other magnetic storage device, or can be used for carrying or storing desired program code unit and can be accessed by general-purpose or special-purpose computer or general-purpose or special-purpose processor in the form of instruction or data structure Any other non-transitory medium.In addition, any connection is appropriately referred to as computer readable medium.For example, if software is to send from website, server or other remote source using coaxial cable, optical fiber cable, twisted pair, digital subscriber line (DSL) or wireless technology such as infrared, radio and microwave, then coaxial cable, optical fiber cable, twisted pair, DSL or wireless technology such as infrared, radio and microwave are included in the definition of computer readable medium. As used herein, disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein 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.

[0169] As used herein (including in the claims), "or" as used in a list of items (e.g., a list of items ending with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, so 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). In addition, as used herein, the phrase "based on" should not be interpreted as a reference to a closed set of conditions. For example, an example step described as "based on condition A" can be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "based at least in part on."

[0170] In the accompanying drawings, similar components or features may have the same reference numeral. In addition, various components of the same type may be distinguished by following the reference numeral with a dash and a second reference numeral, the second reference numeral being used to distinguish between similar components. If only the first reference numeral is used in the specification, the description applies to any of the similar components having the same first reference numeral, without regard to the second reference numeral or other subsequent reference numerals.

[0171] The descriptions set forth herein in conjunction with the accompanying drawings describe example configurations, and do not represent all examples that may be implemented or within the scope of the claims. The term "example" as used herein means "used as an example, instance, or illustration," rather than "preferred" or "advantageous over other examples." For the purpose of providing an understanding of the described techniques, the detailed description includes specific details. However, these techniques may be implemented without these specific details. In some cases, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0172] To enable those skilled in the art to implement or use the present disclosure, the description herein is provided. It will be apparent to those skilled in the art that various modifications to the present disclosure will be apparent, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but is given the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a user equipment UE, comprising: establishing a first wireless connection associated with the first subscription using a first wireless access technology; establishing a second wireless connection associated with a second subscription using a second wireless access technology; performing a call on the second wireless connection; identifying a loss of the first wireless connection based at least in part on executing the call over the second wireless connection; initiating a network discovery process associated with the first subscription using the first radio access technology based at least in part on the loss of the first radio connection, wherein the network discovery process is initiated prior to termination of the call over the second radio connection; and Based at least in part on the loss of the first wireless connection, after the termination of the call on the second wireless connection, reinitiating the network discovery process associated with the first subscription using the first wireless access technology.

2. The method according to claim 1, further comprising: initiating an attach attempt counter, a timer, or both based at least in part on initiating the network discovery process; as well as Based at least in part on the attach attempt counter satisfying a threshold counter, the timer satisfying a threshold duration, or both, performing the network discovery process using the second radio access technology.

3. The method according to claim 2, further comprising: The attach attempt counter, the timer, or both are reset based at least in part on reinitiating the network discovery process after the termination of the call on the second wireless connection.

4. The method according to claim 1, further comprising: A third wireless connection associated with the first subscription is established using the first wireless access technology based at least in part on performing the network discovery process using the first wireless access technology.

5. The method according to claim 1, further comprising: When operating in the standalone mode of operation, an attach procedure is performed with a cell associated with the first subscription, wherein establishing the first radio connection is based at least in part on performing the attach procedure.

6. The method according to claim 1, further comprising: communicating over a first wireless connection associated with the first subscription using a set of communication resources based at least in part on establishing the first wireless connection; as well as The call is performed over the second wireless connection using the set of communications resources, wherein identifying the loss of the first wireless connection is based at least in part on performing the call over the second wireless connection using the set of communications resources.

7. The method according to claim 1, wherein: The first radio connection associated with the first subscription is established using a set of radio frequency hardware resources of the UE, and the second radio connection associated with the second subscription is established using the set of radio frequency hardware resources of the UE.

8. The method according to claim 1, wherein: Performing the call over the second radio connection includes performing a Long Term Evolution (LTE) voice call or a circuit switched fallback call.

9. The method according to claim 1, wherein: The first radio access technology comprises a new radio technology, a fifth generation (5G) technology, or both; and The second radio access technology includes long term evolution technology, fourth generation (4G) technology, or both.

10. An apparatus for wireless communication at a user equipment UE, comprising: processor, a memory coupled to the processor; as well as Instructions, which are stored in the memory and can be executed by the processor to cause the device to perform the following operations: establishing a first wireless connection associated with the first subscription using a first wireless access technology; establishing a second wireless connection associated with a second subscription using a second wireless access technology; performing a call on the second wireless connection; identifying a loss of the first wireless connection based at least in part on executing the call over the second wireless connection; initiating a network discovery process associated with the first subscription using the first radio access technology based at least in part on the loss of the first radio connection, wherein the network discovery process is initiated prior to termination of the call over the second radio connection; and Based at least in part on the loss of the first wireless connection, after the termination of the call on the second wireless connection, reinitiating the network discovery process associated with the first subscription using the first wireless access technology.

11. The device according to claim 10, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: initiating an attach attempt counter, a timer, or both based at least in part on initiating the network discovery process; and Based at least in part on the attach attempt counter satisfying a threshold counter, the timer satisfying a threshold duration, or both, performing the network discovery process using the second radio access technology.

12. The device according to claim 11, wherein The instructions may also be executed by the processor to cause the device to perform the following operations: The attach attempt counter, the timer, or both are reset based at least in part on reinitiating the network discovery process after the termination of the call on the second wireless connection.

13. The device according to claim 10, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: A third wireless connection associated with the first subscription is established using the first wireless access technology based at least in part on performing the network discovery process using the first wireless access technology.

14. The device according to claim 10, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: When operating in the standalone mode of operation, an attach procedure is performed with a cell associated with the first subscription, wherein establishing the first radio connection is based at least in part on performing the attach procedure.

15. The device according to claim 10, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: communicating over a first wireless connection associated with the first subscription using a set of communication resources based at least in part on establishing the first wireless connection; as well as The call is performed over the second wireless connection using the set of communications resources, wherein identifying the loss of the first wireless connection is based at least in part on performing the call over the second wireless connection using the set of communications resources.

16. The device according to claim 10, wherein: The first radio connection associated with the first subscription is established using a set of radio frequency hardware resources of the UE, and the second radio connection associated with the second subscription is established using the set of radio frequency hardware resources of the UE.

17. The device according to claim 10, wherein: The instructions for performing the call on the second wireless connection are executable by the processor to cause the device to perform the following operations: perform a long term evolution (LTE) voice call or a circuit switched fallback call.

18. The apparatus of claim 10, wherein: The first radio access technology comprises a new radio technology, a fifth generation (5G) technology, or both; and The second radio access technology includes long term evolution technology, fourth generation (4G) technology, or both.

19. An apparatus for wireless communication at a user equipment UE, comprising: means for establishing a first wireless connection associated with a first subscription using a first wireless access technology; means for establishing a second wireless connection associated with a second subscription using a second wireless access technology; means for performing a call on the second wireless connection; means for identifying a loss of the first wireless connection based at least in part on conducting the call over the second wireless connection; means for initiating a network discovery process associated with the first subscription using the first radio access technology based at least in part on the loss of the first radio connection, wherein the network discovery process is initiated prior to termination of the call over the second radio connection; as well as Means for reinitiating the network discovery process associated with the first subscription using the first radio access technology after the termination of the call on the second radio connection based at least in part on the loss of the first radio connection.

20. The apparatus according to claim 19, further comprising: means for initiating an attach attempt counter, a timer, or both based at least in part on initiating the network discovery process; as well as Means for performing the network discovery procedure using the second radio access technology based at least in part on the attach attempt counter satisfying a threshold counter, the timer satisfying a threshold duration, or both.

21. The apparatus according to claim 20, further comprising: Means for resetting the attach attempt counter, the timer, or both based at least in part on reinitiating the network discovery process after the termination of the call on the second wireless connection.

22. The apparatus of claim 19, further comprising: Means for establishing a third wireless connection associated with the first subscription using the first wireless access technology based at least in part on performing the network discovery process using the first wireless access technology.

23. The apparatus of claim 19, further comprising: Means for performing an attach procedure with a cell associated with the first subscription while operating in a standalone mode of operation, wherein establishing the first radio connection is based at least in part on performing the attach procedure.

24. The apparatus of claim 19, further comprising: means for communicating over a first radio connection associated with the first subscription using a set of communication resources based at least in part on establishing the first radio connection; as well as Means for executing the call over the second wireless connection using the set of communications resources, wherein identifying the loss of the first wireless connection is based at least in part on executing the call over the second wireless connection using the set of communications resources.

25. The device according to claim 19, wherein The first radio connection associated with the first subscription is established using a set of radio frequency hardware resources of the UE, and the second radio connection associated with the second subscription is established using the set of radio frequency hardware resources of the UE.

26. The device according to claim 19, wherein The means for performing the call over the second radio connection may include means for performing a Long Term Evolution (LTE) voice call or a circuit switched fallback call.

27. The apparatus of claim 19, wherein: The first radio access technology comprises a new radio technology, a fifth generation (5G) technology, or both; and The second radio access technology includes long term evolution technology, fourth generation (4G) technology, or both.

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