Voice fallback in 5G NR

Abstract

This disclosure provides systems, methods, apparatuses, and computer-readable media for wireless communication. In some aspects, a user equipment (UE) can receive a mobility command from a first base station (BS) associated with a 5G NR radio access technology (RAT) to a second RAT. The UE can determine that the mobility command is for voice fallback. Based at least in part on the determination that the mobility command is for voice fallback, the UE can send a Radio Resource Control (RRC) connection request communication to a second BS associated with the second RAT to attempt to establish a communication connection with the second BS for voice fallback.

Description

[0001] This application is a divisional application of the application filed on January 9, 2020, with application number 202080010152.3 and titled "Voice fallback in 5G NR".

[0002] Cross-reference to related applications

[0003] This application claims priority to U.S. Provisional Application No. 62 / 797,663, filed January 28, 2019, entitled “VOICE FALLBACK IN 5G NR”, and U.S. Non-Provisional Application No. 16 / 737,639, filed January 8, 2020, entitled “VOICE FALLBACK IN 5G NR”, which are expressly incorporated herein by reference. Technical Field

[0004] In general, aspects of this disclosure relate to wireless communications, and more specifically, aspects of this disclosure relate to techniques and apparatus for voice fallback in fifth-generation (5G) new radio (NR). Background Technology

[0005] Wireless communication systems have been widely deployed to provide a variety of telecommunications services such as telephone, video, data, messaging, and broadcasting. Typical wireless communication systems employ multiple access technologies that support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access technologies include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems, and Long Term Evolution (LTE). LTE / LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard issued by the 3rd Generation Partnership Project (3GPP).

[0006] A wireless communication network may include multiple base stations (BSs), where each BS can support communication for multiple user equipment (UEs). UEs can communicate with the base stations (BSs) via downlinks and uplinks. A downlink (or forward link) refers to the communication link from the BS to the UE, while an uplink (or reverse link) refers to the communication link from the UE to the BS. As further described in detail herein, a BS may refer to a node B, gNB, access point (AP), radio headend, transmit / receive point (TRP), new radio (NR) BS, 5G node B, or other examples, or combinations thereof.

[0007] The above multiple access technology has been adopted in various telecommunications standards to provide a universal protocol that enables different user equipment to communicate across city limits, countries, regions, and even globally. New Radio (NR) (also known as 5G) is an evolution set of the LTE mobile standard released by the 3rd Generation Partnership Project (3GPP). NR is designed to better support mobile broadband internet access by improving spectral efficiency, reducing costs, enhancing service, fully utilizing new spectrum, using Orthogonal Frequency Division Multiplexing (OFDM) with a Cyclic Prefix (CP) on the downlink (DL), using CP-OFDM or SC-FDM (also known as Discrete Fourier Transform Spread Spectrum OFDM (DFT-s-OFDM)) on the uplink (UL), and supporting beamforming, multiple-input multiple-output (MIMO) antenna technologies, and carrier aggregation. Summary of the Invention

[0008] The systems, methods, and apparatuses disclosed herein are innovative in several ways, but none of these aspects alone contributes to the desired characteristics disclosed herein.

[0009] One innovative aspect of the subject matter described in this disclosure can be implemented in a method of wireless communication performed by a user equipment (UE). The method may include: receiving a mobility command from a first base station (BS) associated with a fifth-generation new radio (5G NR) radio access technology (RAT) to a second RAT. The method may include: determining that the mobility command is for voice fallback. The method may include: at least in part based on the determination that the mobility command is for voice fallback, sending a radio resource control (RRC) connection request communication to a second BS associated with the second RAT for attempting to establish a communication connection with the second BS for voice fallback.

[0010] In some aspects, the second RAT includes: a Long Term Evolution (LTE) RAT or a Third Generation (3G) RAT. In some aspects, determining that the mobility command is for voice fallback includes: determining that the mobility command is for voice fallback based at least in part on identifying a voice fallback indication included in the mobility command. In some aspects, the mobility command includes: MobilityFromNRCommand NR RRC communication, HandoverPreparationInformation Long Term Evolution (LTE) RRC communication, RRCLease NR RRC communication, a source Radio Network Controller (RNC) to target RNC transparent container, or a Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (TRAN) RRC connection request communication.

[0011] In some aspects, determining that the mobility command is for voice fallback includes: determining that the mobility command is for voice fallback based at least in part on receiving the mobility command when establishing the voice call, or the UE's ability to implement NR voice (VoNR) voice calls. In some aspects, the RRC connection request communication indicates the voice call as a cause value.

[0012] In some aspects, the method further includes: detecting the failure of the attempt to establish a communication connection with the second BS; and, at least in part based on the detection of the failure of the attempt to establish a communication connection with the second RAT, and at least in part based on receiving the mobility command, attempting to establish a communication connection with a third BS associated with the second RAT. In some aspects, the first BS and the second BS are the same BS, the 5G NR RAT is associated with a first cell of the same BS, and the second RAT is associated with a second cell of the same BS. In some aspects, the first BS and the second BS are different BSs, the 5G NR RAT is associated with a cell of the first BS, and the second RAT is associated with a cell of the second BS.

[0013] In some respects, the first BS, the second BS, and the third BS are the same BS, the 5G NR RAT is associated with a first cell of the same BS, the second RAT is associated with a second cell of the same BS, and the second RAT is associated with a third cell of the same BS. In other respects, the first BS, the second BS, and the third BS are different BSs, the 5G NR RAT is associated with a cell of the first BS, the second RAT is associated with a cell of the second BS, and the second RAT is associated with a cell of the third BS.

[0014] In some respects, the second BS and the third BS are different BSs, the second RAT is associated with a cell of the second BS, and the second RAT is associated with a cell of the third BS. In some respects, the second BS and the third BS are the same BS, the second RAT is associated with a first cell of the same BS, and the second RAT is associated with a second cell of the same BS. In some respects, the first BS and the third BS are the same BS, the 5G NR RAT is associated with a first cell of the same BS, and the second RAT is associated with a second cell of the same BS.

[0015] Another innovative aspect of the subject matter described in this disclosure can be implemented in a UE for wireless communication. The UE may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: receive a mobility command from a first BS associated with a 5G NR RAT to a second RAT. The memory and the one or more processors may be configured to: determine that the mobility command is for voice fallback. The memory and the one or more processors may be configured to: send an RRC connection request communication to a second BS associated with the second RAT, at least in part based on the determination that the mobility command is for voice fallback, for attempting to establish a communication connection with the second BS for voice fallback. In some aspects, the UE may perform or implement any one or more of the aspects described in combination with the methods described above or elsewhere herein.

[0016] Another innovative aspect of the subject matter described in this disclosure can be implemented in a non-transitory computer-readable medium. The non-transitory computer-readable medium can store one or more instructions for wireless communication. When the one or more instructions are executed by one or more processors of the UE, the one or more processors can cause the one or more processors to receive a mobility command from a first BS associated with a 5G NR RAT to a second RAT. When the one or more instructions are executed by one or more processors of the UE, the one or more processors can determine that the mobility command is for voice fallback. When the one or more instructions are executed by one or more processors of the UE, the one or more processors can send an RRC connection request communication to a second BS associated with a second RAT, at least in part based on the determination that the mobility command is for voice fallback, to attempt to establish a communication connection with the second BS for voice fallback. In some aspects, the non-transitory computer-readable medium can perform or implement any one or more of the aspects described in combination with the methods described above or elsewhere herein.

[0017] Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication. The apparatus may include: a unit for receiving a mobility command from a first BS associated with a 5G NR RAT to a second RAT. The apparatus may include: a unit for determining that the mobility command is for voice fallback. The apparatus may include: a unit for sending an RRC connection request communication to a second BS associated with the second RAT, at least in part based on the determination that the mobility command is for voice fallback, for attempting to establish a communication connection with the second BS for voice fallback. In some aspects, the apparatus may perform or implement any one or more of the aspects described in combination with the methods described above or elsewhere herein.

[0018] Another innovative aspect of the subject matter described in this disclosure can be implemented in a method for wireless communication performed by a BS. The method may include: determining that a UE communicatively connected to the BS is establishing a voice call, wherein the BS is associated with a 5G NR RAT. The method may include: based at least in part on determining that the UE is establishing the voice call, sending a mobility command from the 5G NR RAT to a second RAT, wherein the mobility command includes a voice fallback indication.

[0019] In some aspects, the second RAT includes an LTE RAT or a 3G RAT. In some aspects, sending the mobility command includes sending the mobility command to at least one of another BS or the UE. In some aspects, the mobility command includes at least one of the following: a transparent container included in an S1AP communication sent to another BS, a RANAP communication sent to the other BS, a HandoverPreparationInformation LTERRC communication sent to the other BS, a MobilityFromNRCommand NR RRC communication sent to the UE, a HandoverCommand LTE RRC communication sent to the UE, an RRCRelease NR RRC communication sent to the UE, a source RNC to target RNC transparent container, or a UTRAN RRC connection request communication.

[0020] Another innovative aspect of the subject matter described in this disclosure can be implemented in a BS for wireless communication. The BS may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: determine that a UE communicatively connected to the BS is establishing a voice call, wherein the BS is associated with a 5G NR RAT. The memory and the one or more processors may be configured to: based at least in part on the determination that the UE is establishing the voice call, send a mobility command from the 5G NR RAT to a second RAT, wherein the mobility command includes a voice fallback indication. In some aspects, the BS may perform or implement any one or more of the aspects described in combination with the methods described above or elsewhere herein.

[0021] Another innovative aspect of the subject matter described in this disclosure can be implemented in a non-transitory computer-readable medium. The non-transitory computer-readable medium may store one or more instructions for wireless communication. When the one or more instructions are executed by one or more processors of a UE, the one or more processors may determine that a UE communicatively connected to a BS is establishing a voice call, wherein the BS is associated with a 5G NR RAT. When the one or more instructions are executed by one or more processors of a UE, the one or more processors may, at least in part based on the determination that the UE is establishing the voice call, send a mobility command from the 5G NR RAT to a second RAT, wherein the mobility command includes a voice fallback indication. In some aspects, the non-transitory computer-readable medium may perform or implement any one or more of the aspects described in combination with the methods described above or elsewhere herein.

[0022] Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication. The apparatus may include: a unit for determining that a UE communicatively connected to the BS is establishing a voice call, wherein the apparatus is associated with a 5G NR RAT. The apparatus may also include: a unit for sending a mobility command from the 5G NR RAT to a second RAT, at least in part based on the determination that the UE is establishing the voice call, wherein the mobility command includes a voice fallback indication. In some aspects, the apparatus may perform or implement any one or more of the aspects described in combination with the methods described above or elsewhere herein.

[0023] Aspects of this document generally include methods, apparatus, systems, computer program products, non-transitory computer-readable media, user equipment, base stations, wireless communication devices, and processing systems, as fully described herein with reference to the accompanying drawings and description, and as illustrated in the drawings and description.

[0024] To better understand the following detailed description, the features and technical advantages of the examples according to this disclosure have been generally summarized above. Further features and advantages will be described below. The disclosed concepts and specific examples can be readily used as the basis for modifying or designing other structures to perform the same purpose as this disclosure. These equivalent constructions do not depart from the scope of the appended claims. The characteristics of the concepts disclosed herein (regarding their organization and operation) and the associated advantages will be better understood when considering the following detailed description in conjunction with the accompanying drawings. Each of these drawings is provided for illustrative and descriptive purposes only and is not intended to limit the invention. Attached Figure Description

[0025] Figure 1 This is a block diagram that conceptually illustrates an example of a wireless network.

[0026] Figure 2 It is a block diagram that conceptually depicts an example of communication between a base station (BS) and a user equipment (UE) in a wireless network.

[0027] Figure 3 This is a diagram illustrating an example of voice fallback in fifth-generation (5G) new radio (NR).

[0028] Figure 4 This is a diagram illustrating, for example, an exemplary process performed by the UE.

[0029] Figure 5 This is a diagram illustrating an exemplary process, for example, performed by a BS.

[0030] The same reference numerals and designations in the various figures indicate the same elements. Detailed Implementation

[0031] The various aspects of this disclosure are described more fully below with reference to the accompanying drawings. However, this disclosure may be implemented in many different forms and should not be construed as limited to any particular structure or function given throughout this disclosure. Rather, these aspects are provided only to make this disclosure thorough and complete, and to fully convey the scope of protection of this disclosure to those skilled in the art. Based on this application, those skilled in the art should understand that the scope of this disclosure is intended to cover any aspect of the disclosure herein, whether implemented independently or in combination with any other aspect of this disclosure. For example, an apparatus or method may be implemented using any number of the aspects set forth herein. Furthermore, the scope of this disclosure is intended to cover such apparatus or methods that may be implemented using other structures, functions, or structures and functions other than those set forth herein, or structures and functions different from those set forth herein. It should be understood that any aspect of the disclosure herein may be implemented by one or more components of the invention.

[0032] The following describes some aspects of a telecommunications system with reference to various devices and techniques. These devices and techniques will be described in the following detailed embodiments and depicted in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using hardware, software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0033] It should be noted that although this document uses terms commonly associated with 3G or 4G wireless technologies to describe aspects of this document, aspects of this disclosure may also be applied to communication systems based on other generations (e.g., 5G and beyond, which include New Radio (NR) technologies).

[0034] In some 5G NR deployments, the 5G next-generation node B (gNB) may not support NR Voice (VoNR). To support voice calls in 5G NR deployments, a voice fallback process can be implemented from 5G NR to another radio access technology (RAT) (e.g., Long Term Evolution (LTE) or 3G) to serve voice calls. This process may include a handover or redirection from the gNB to the LTE evolved Node B (eNB) (VoNR to LTE Voice (VoLTE) voice fallback), a handover or redirection from the gNB to the 3G node B (VoNR to 3G circuit-switched voice fallback), or another type of 5G NR voice fallback process.

[0035] In some cases, during a 5G NR voice fallback process, the source BS (the BS serving the UE) may not notify the UE or the target BS (the BS to which the UE will hand over or redirect) that the handover or redirection is for the purpose of 5G NR voice fallback. As a result, the target BS may not be aware that it will prioritize radio resource allocation to the UE to support the voice call associated with that UE, which may lead to delays in voice call setup, degraded voice call service performance, and so on. Furthermore, if the handover or redirection fails, and the UE is unaware that the handover or redirection is for the purpose of 5G NR voice fallback, the UE may return to the source BS (which does not support voice calls) instead of re-attempting to connect to the target BS or another BS that supports voice calls, which may lead to further delays in establishing the voice call.

[0036] Some aspects described herein provide techniques and apparatus for voice fallback in 5G NR. In some aspects, the source BS can receive an indication that the UE is establishing a voice call. The source BS may include a gNB or another type of BS that does not support VoNR. Thus, the source BS can initiate a 5G NR voice fallback process, which may include the UE handing over or redirecting to a target BS associated with a RAT that supports another voice service (e.g., LTE (VoLTE), 3G (Circuit-Switched Voice), or more examples). During the 5G NR voice fallback process, the source BS may send a command of mobility to the UE and the target BS, which may include an indication that the handover or redirection is for 5G NR voice fallback.

[0037] This method informs the target BS that the handover or redirection is for 5G NR voice fallback, allowing the target BS to prioritize radio resource allocation to the UE to support voice calls. This reduces voice call setup latency and minimizes performance degradation in voice call services. Furthermore, this method informs the UE that the handover or redirection is for 5G NR voice fallback, allowing the UE to perform various actions, such as instructing the target BS that it is attempting to connect to the target BS for 5G NR voice fallback, or automatically retrying to connect to the target BS or another BS supporting voice calls (before returning to the source BS) if the handover or redirection fails. This further reduces voice call setup latency.

[0038] Figure 1This is a block diagram conceptually illustrating an example of a wireless network 100. Wireless network 100 can be an LTE network or some other wireless network (e.g., a 5G or NR network). Wireless network 100 can include multiple BS110s (shown as BS110a, BS110b, BS110c, and BS110d) and other network entities. A BS is an entity that communicates with a UE; a BS can also be referred to as a base station, NR BS, Node B, gNB, 5G Node B (NB), access point, Transmitter Receiver Point (TRP), or other examples, or combinations thereof. Each BS can provide communication coverage for a specific geographic area. In 3GPP, depending on the context in which the term "cell" is used, the term "cell" can refer to the coverage area of ​​a BS or a BS subsystem serving that coverage area.

[0039] A BS can provide communication coverage for macrocells, picocells, femtocells, or another type of cell. A macrocell can cover a relatively large geographic area (e.g., a radius of several kilometers), allowing unrestricted access for UEs with service subscriptions. A picocell can cover a relatively small geographic area, allowing unrestricted access for UEs with service subscriptions. A femtocell can cover a relatively small geographic area (e.g., a home), allowing restricted access for UEs associated with that femtocell (e.g., UEs in a closed user group (CSG)). A BS used for macrocells can be called a macro BS. A BS used for picocells can be called a pico BS. A BS used for femtocells can be called a femto BS or a home BS. Figure 1 In the example shown, BS110a can be a macro BS for macro cell 102a, BS110b can be a pico BS for pico cell 102b, and BS110c can be a femto BS for femto cell 102c. A BS can support one or more (e.g., three) cells. The terms “eNB,” “base station,” “NR BS,” “gNB,” “TRP,” “AP,” “Node B,” “5G NB,” and “cell” are used interchangeably.

[0040] In some examples, the cell does not need to be stationary; the geographical area of ​​the cell can move depending on the location of the mobile BS. In some examples, BSs can use any suitable transport network to interconnect with each other or to one or more other BSs or network nodes (not shown) in the access wireless network 100 via various types of backhaul interfaces (e.g., direct physical connection, virtual network, or other examples).

[0041] The wireless network 100 may also include a relay station. A relay station is an entity that can receive data transmissions from an upstream station (e.g., a BS or a UE) and transmit those data transmissions to a downstream station (e.g., a UE or a BS). A relay station can also be a UE capable of relaying transmissions from other UEs. Figure 1 In the example shown, relay station 110d can communicate with macro BS110a and UE 120d to facilitate communication between BS110a and UE 120d. A relay station can also be referred to as a relay BS, relay base station, repeater, etc.

[0042] Wireless network 100 can be a heterogeneous network comprising different types of Base Stations (BSs) (e.g., macro BSs, pico BSs, femto BSs, relay BSs, etc.). These different types of BSs can have different transmit power levels, different coverage areas, and different effects on interference in wireless network 100. For example, macro BSs can have higher transmit power levels (e.g., 5 to 40 watts), while pico BSs, femto BSs, and relay BSs can have lower transmit power levels (e.g., 0.1 to 2 watts).

[0043] Network controller 130 can be coupled to a group of base stations (BSs) and provide coordination and control for these BSs. Network controller 130 can communicate with these BSs via backhaul. These BSs can also communicate with each other, for example, directly or indirectly via wireless or wired backhaul.

[0044] UEs 120 (e.g., 120a, 120b, 120c) may be distributed throughout the wireless network 100, and each UE may be stationary or mobile. A UE may also be referred to as an access terminal, terminal, mobile station, user unit, station, etc. A UE may be a cellular phone (e.g., a smartphone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet device, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, a biosensor / device, a wearable device (smartwatch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device, or a satellite radio device), an in-vehicle component or sensor, a smart meter / sensor, industrial manufacturing equipment, a GPS device, or any other suitable device configured to communicate via wireless or wired media.

[0045] Some UEs can be viewed as Machine-Type Communication (MTC) UEs or Evolved or Enhanced Machine-Type Communication (eMTC) UEs. For example, MTC and eMTC UEs include robots, drones, remote devices, sensors, meters, monitors, location tags, etc., capable of communicating with a base station, another device (e.g., a remote device), or some other entity. For example, a wireless node can provide connectivity to or from a network (e.g., a wide area network such as the Internet or cellular networks) via wired or wireless communication links. Some UEs can be considered Internet of Things (IoT) devices or can be implemented as NB-IoT (Narrowband Internet of Things) devices. Some UEs can be considered Customer Premises Equipment (CPE). UE 120 can be included in a housing that houses the components of UE 120 (e.g., processor components, memory components, or other examples, or combinations thereof).

[0046] Typically, any number of wireless networks can be deployed within a given geographical area. Each wireless network can support a specific Radio Access Platform (RAT) and operate on one or more frequencies. A RAT can also be referred to as a radio technology, air interface, etc. A frequency can also be referred to as a carrier, frequency channel, etc. Each frequency can support a single RAT within a given geographical area to avoid interference between wireless networks using different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0047] In some instances, access to the air interface can be scheduled, such as when a scheduling entity (e.g., a base station) allocates resources for communication between some or all devices and equipment within its service area or cell. In this disclosure, as further discussed below, the scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, the subordinate entity utilizes the resources allocated by the scheduling entity.

[0048] A base station is not the only entity that can be used as a scheduling entity. In some examples, a UE can act as a scheduling entity, scheduling resources for one or more subordinate entities (e.g., one or more other UEs). In this example, the UE acts as the scheduling entity, and other UEs utilize the resources scheduled by the UE for wireless communication. A UE can act as a scheduling entity in a peer-to-peer (P2P) network or a mesh network. In the mesh network example, in addition to communicating with the scheduling entity, UEs can optionally communicate directly with each other.

[0049] Therefore, in wireless communication networks with scheduled access to time-frequency resources and with cellular, P2P, and mesh configurations, a scheduling entity and one or more subordinate entities can communicate using the scheduled resources.

[0050] In some respects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly using one or more lateral link channels (e.g., without using base station 110 as an intermediary device). For example, UEs 120 may communicate using peer-to-peer (P2P) communication, device-to-device (D2D) communication, vehicular wireless communication (V2X) protocols (e.g., which may include vehicle-to-vehicle (V2V) protocols, vehicle-to-infrastructure (V2I) protocols, or other examples, or combinations thereof), mesh networks, or other examples, or combinations thereof. In this case, UE 120 may perform scheduling operations, resource selection operations, or other operations described elsewhere herein by base station 110.

[0051] Figure 2 This is a block diagram 200 conceptually illustrating an example 200 of communication between base station 110 and UE 120 in a wireless network. Base station 110 and UE 120 can be respectively... Figure 1 One of the base stations in the middle and Figure 1 One of the UEs in the system. Base station 110 can be equipped with T antennas 234a to 234t, and UE 120 can be equipped with R antennas 252a to 252r, where T≥1 and R≥1.

[0052] At base station 110, transmit processor 220 can receive data for one or more UEs from data source 212, select one or more modulation and coding schemes (MCS) for each UE based at least in part on the channel quality index (CQI) received from each UE, process the data for each UE (e.g., coding and modulation) based at least in part on the MCS selected for each UE, and provide data symbols for all UEs. Transmit processor 220 can also process system information (e.g., for semi-static resource allocation information (SRPI), etc.) and control information (e.g., CQI requests, grants, upper-layer signaling, etc.), and provide overhead symbols and control symbols. Transmit processor 220 can also generate reference symbols for reference signals (e.g., cell-specific reference signals (CRS)) and synchronization signals (e.g., primary synchronization signal (PSS) and secondary synchronization signal (SSS)). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 can perform spatial processing (e.g., precoding) on ​​these data symbols, control symbols, overhead symbols, or reference symbols (if any) and provide T output symbol streams to T modulators (MODs) 232a to 232t. Each modulator 232 can process its own output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232 can further process (e.g., convert to analog signal, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The T downlink signals from modulators 232a to 232t can be transmitted via T antennas 234a to 234t respectively. Position coding can be used to generate synchronization signals to transmit other information, according to the aspects described in further detail below.

[0053] At UE 120, antennas 252a to 252r can receive downlink signals from base station 110 or other base stations, and provide the received signals to demodulators 254a to 254r respectively. Each demodulator 254 can adjust (e.g., filter, amplify, down-convert, and digitize) its respective received signal to obtain an input sample. Each demodulator 254 can further process these input samples (e.g., for OFDM, etc.) to obtain received symbols. MIMO detector 256 can obtain the received symbols from all R demodulators 254a to 254r, perform MIMO detection (if any) on the received symbols, and provide the detected symbols. Receiver processor 258 can process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to data sink 260, and provide decoded control information and system information to controller or processor (controller / processor) 280. The channel processor can determine the Received Reference Signal Power (RSRP), Received Signal Strength Indicator (RSSI), Received Reference Signal Quality (RSRQ), Channel Quality Indicator (CQI), and so on. In some respects, one or more components of the UE 120 may be contained within a housing.

[0054] On the uplink, at UE 120, transmit processor 264 can receive data from data source 262 and control information (e.g., for reports including RSRP, RSSI, RSRQ, CQI, etc.) from controller / processor 280, and process the data and control information. Transmit processor 264 can also generate reference symbols for one or more reference signals. Symbols from transmit processor 264 can be pre-encoded (if any) by TX MIMO processor 266, further processed by modulators 254a to 254r (e.g., for DFT-s-OFDM, CP-OFDM, etc.), and transmitted back to base station 110. At base station 110, uplink signals from UE 120 and other UEs can be received by antenna 234, processed by demodulator 232, detected (if any) by MIMO detector 236, and further processed by receive processor 238 to obtain decoded data and control information transmitted by UE 120. The receiving processor 238 can provide decoded data to the data sink 239 and decoded control information to the controller or processor (controller / processor) 240. The base station 110 may include a communication unit 244 and communicate with the network controller 130 via the communication unit 244. The network controller 130 may include a communication unit 294, a controller or processor (controller / processor) 290, and a memory 292.

[0055] Figure 2The controller / processor 240 of base station 110, the controller / processor 280 of UE 120, or any other component may execute one or more technologies associated with voice backoff for 5G NR, as further described in detail elsewhere herein. For example, Figure 2 The controller / processor 240 of base station 110, the controller / processor 280 of UE 120, or any other component can perform or direct, for example... Figure 4 Processing 400 Figure 5 The system can perform processing operations 500, or other processing operations as described herein. Memory 242 and 282 can store data and program code for base station 110 and UE 120, respectively. Scheduler 246 can schedule the UE to transmit data on the downlink or uplink.

[0056] When the stored program code is executed by the controller / processor 280 or other processors and modules at UE 120, UE 120 can execute the reference. Figure 4 The processing 400 or other processing described herein may be performed. When the stored program code is executed by the controller / processor 240 or other processors and modules at the base station 110, the base station 110 may perform the operations described herein. Figure 5 The process can be handled by 500 or other processes as described herein. Scheduler 246 can schedule the UE to transmit data on the downlink or uplink.

[0057] In some aspects, UE 120 may include: a unit for receiving a command from a first BS associated with a 5G NR RAT for mobility from the 5G NR RAT to a second RAT; a unit for determining that the mobility command is for voice fallback; a unit for sending RRC connection request communication to a second BS 110 associated with the second RAT, at least in part based on the determination that the mobility command is for voice fallback, for attempting to establish a communication connection with the second BS 110S for voice fallback, or other examples, or combinations thereof. In some aspects, these units may include combinations of... Figure 2 One or more components of the described UE 120.

[0058] In some aspects, base station 110 may include: a unit for determining that UE 120, which is communicatively connected to BS 110, is establishing a voice call, wherein the BS is associated with a 5G NR RAT; and a unit for sending a mobility command from the 5G NR RAT to a second RAT, at least in part based on the determination that UE 120 is establishing a voice call, wherein the mobility command includes a voice fallback indication, or other examples, or combinations thereof. In some aspects, these units may include combinations of... Figure 2One or more components of the described base station 110.

[0059] Although Figure 2 The blocks shown are represented as different components, but the functions described above with respect to these blocks can be implemented in a single hardware, software, or combined component, or in various combinations of components. For example, the functions described with respect to transmit processor 264, receive processor 258, or TX MIMO processor 266 can be executed by controller / processor 280, or executed under the control of controller / processor 280.

[0060] Figure 3 This is a diagram illustrating example 300 of voice fallback for 5G NR. (See diagram 300.) Figure 3 As shown, example 300 may include a UE (e.g., in...) Figure 1 The UE 120a-120e described and illustrated in [the text] or in [the text] Figure 2 The UE 120 described and illustrated in the text and multiple BSs (e.g., in Figure 1 BS110a-110d as depicted and described in or in Figure 2 (BS110 as depicted in the diagram). In some aspects, BS110a may include a gNB associated with a 5G NR RAT. In some aspects, BS110b and BS110c may include another type of BS, such as an eNB associated with an LTE RAT, a 3G node B associated with a 3G RAT, or other examples.

[0061] In some aspects, the multiple BSs can represent multiple cells provided by one or more BSs. For example, a single BS can provide the multiple cells, wherein a first cell of the BS (corresponding to BS110a) is associated with a 5G NR RAT, a second cell of the BS (corresponding to BS110b) is associated with an LTE RAT or a 3G RAT, and a third cell of the BS (corresponding to BS110c) is associated with an LTE RAT or a 3G RAT. As another example, the first cell associated with a 5G NR RAT (corresponding to BS110a) can be provided by a first BS, the second cell associated with an LTE RAT or a 3G RAT (corresponding to BS110b) can be provided by a second BS (different from or the same as the first BS), and the third cell associated with an LTE RAT or a 3G RAT (corresponding to BS110c) can be provided by a third BS (different from or the same as the first BS, different from or the same as the second BS, or other examples).

[0062] like Figure 3As shown, UE 120 can establish a voice call via reference numeral 302. In some aspects, this voice call may include a Mobile Station Initiated (MO) voice call (a voice call initiated by UE 120), a Mobile Station Terminated (MT) voice call (a voice call terminated at UE 120), or other examples. In some aspects, UE 120 can establish the voice call by initiating a Quality of Service (QoS) flow for the connection to the Internet Protocol Multimedia Subsystem (IMS) serving the voice call. This QoS flow may be associated with one or more QoS parameters of the voice call, such as packet loss rate parameters, latency parameters, throughput parameters, packet error rate parameters, or other QoS parameters.

[0063] In some respects, BS110a can determine that UE 120 is establishing a voice call. For example, BS110a can identify the QoS flow for the voice call, at least in part, based on an indication of the QoS flow received from UE 120. This indication may include a 5G QoS identifier (5QI) or another type of identifier.

[0064] In some respects, because BS110a is associated with a RAT that does not support voice calls, BS110a can determine that it does not support QoS flows. Therefore, BS110a can refuse the establishment of a QoS flow and can initiate a 5G NR voice fallback from UE 120 to BS110b, where BS110b can support voice calls. As mentioned above, BS110b can be associated with an LTE RAT, a 3G RAT, or another type of RAT that supports voice calls.

[0065] like Figure 3As further shown by reference numeral 304, in order to initiate a 5G NR voice fallback, BS110a can send a mobility command to UE 120, BS110b, or a combination of UE 120 and BS110b. This mobility command can be a voice fallback from a 5G NR RAT to another RAT that supports voice calls (e.g., an LTE RAT or a 3G RAT). In some aspects, when sending a mobility command to UE 120, the mobility command can include handover communication or redirection communication. In some aspects, the handover communication can include MobilityFromNRCommand NR RRC communication, HandoverCommand LTE RRC communication, or another type of handover communication. In some aspects, the redirection communication can include RRCRelease (RRC release) NR RRC communication or another type of redirection communication. In some aspects, the mobility command can include a source Radio Network Controller (RNC) to target RNC transparent container, or a Universal Mobile Telecommunications System Terrestrial Radio Access Network (UTRAN) RRC connection request communication (if the other RAT is a 3G RAT).

[0066] In some respects, the BS110a may include a voice fallback indication in the mobility command. This voice fallback indication may include an information element (IE) such as a voiceFallbackIndication IE or another type of IE, indicating that the mobility command is for voice fallback from a 5G NR RAT to another RAT that supports voice calls.

[0067] In some aspects, when a mobility command is sent to the BS110b, the mobility command may include S1 Application Protocol (S1AP) communication, Radio Access Network Application Part (RANAP) communication, RRC communication, or similar types of communication. RRC communication may include Handover Preparation Information LTE RRC communication or another type of RRC communication. If the BS110b is associated with an LTE RAT, the mobility command may include a voice fallback indication (e.g., a voiceFallbackIndication IE or another type of IE) indicating that the mobility command is for voice fallback from a 5G NR RAT to another RAT that supports voice calls. If the BS110b is associated with a 3G RAT or another type of RAT that supports circuit-switched voice calls, the mobility command may include a voice fallback indication such as a Circuit-Switched Fallback (CSFB) Information IE or another type of IE to indicate that the mobility command is for voice fallback from a 5G NR RAT to another RAT that supports voice calls.

[0068] like Figure 3 As further shown in the figure, by reference numeral 306, UE 120 can attempt to establish a communication connection with BS110b by sending an RRC connection request communication to BS110b. In some respects, UE 120 can send the RRC connection request communication at least in part based on receiving a mobility command and determining that the mobility command is for voice fallback.

[0069] In some aspects, UE 120 may determine that a mobility command is for voice fallback based at least in part on identifying a voice fallback indication included in a mobility command (which indicates that the mobility command is for voice fallback). In some aspects, UE 120 may implicitly determine that a mobility command is for voice fallback based at least in part on: receiving the mobility command at the time of establishing a voice call; at least in part on whether UE 120 is able to make a VoNR voice call (e.g., if UE 120 is unable to make a VoNR voice call, then UE 120 may infer that the handover or redirection is for voice fallback), or other examples, or combinations thereof.

[0070] In some respects, UE 120 can include an indication in its RRC connection request that the voice call is a reason value used for the RRC connection request communication. This reason value can indicate to BS110b the purpose of UE 120's attempt to establish a communication connection with BS110b. BS110b can use the indication of the voice call in the RRC connection request communication to prioritize radio resource allocation to UE 120. In this way, UE 120 can be assigned a higher priority relative to other UEs connected to BS110b to ensure the success of the 5G NR voice fallback process.

[0071] like Figure 3 As further shown in the figure, UE 120 can detect the failure of an attempt to establish a communication connection with BS 110b by means of reference numeral 308. For example, UE 120 can determine that the connection cannot be established within a specific time window used to establish the connection, and therefore can determine that the attempt to establish a communication connection with BS 110b has failed or was unsuccessful.

[0072] like Figure 3 As further shown in the figure, by reference numeral 310, the UE 120 can perform various actions at least in part based on the detection of a failed attempt to establish a communication connection with the BS110b, and at least in part based on the fact that the mobility command is for 5G NR voice fallback. For example, and as... Figure 3 As shown, a communication connection can be attempted with BS110c, which can be associated with an LTE RAT, a 3G RAT, or another RAT that supports voice calls. As another example, UE 120 can retry a communication connection with BS110b. In this way, UE 120 can reduce latency caused by failed connection attempts by trying to connect to a BS associated with a RAT that supports voice calls, rather than reconnecting to BS110a associated with a RAT that may not support voice calls.

[0073] like Figure 3As further shown by reference numeral 312, once UE 120 is communicatively connected to BS 110c, BS 110c can prioritize UE 120 to support voice calls. In some aspects, BS 110c can prioritize UE 120 at least partially based on a voice backoff indication received from BS 110a, at least partially based on a voice call reason value indicated by UE 120, or a combination thereof. In some aspects, BS 110c can prioritize UE 120 when allocating radio resources associated with BS 110c. For example, BS 110c can be configured to prioritize voice calls relative to other types of packet traffic (e.g., ensuring voice quality and delay parameters are met), and therefore can preferentially allocate radio resources to UE 120 relative to allocating radio resources to other UEs communicatively connected to BS 110c.

[0074] Therefore, BS110a can initiate a 5G NR voice fallback process, which may include a handover or redirection of UE 120 to BS110b. During the 5G NR voice fallback process, BS110a can send a mobility command to UE 120 and BS110b. This mobility command may include an indication that the mobility command is for 5G NR voice fallback to another RAT that supports voice calls. In this way, BS110b is informed that the handover or redirection of UE 120 to BS110b is for the purpose of 5G NR voice fallback, thereby allowing BS110b to prioritize radio resource allocation to UE 120 to optimize the cell associated with BS110b to support voice calls. This can reduce the latency of establishing voice calls and reduce the performance degradation of voice call services. In addition, this method informs UE 120 that the handover or redirection is for the purpose of 5G NR voice fallback, thereby allowing UE 120 to perform various actions, such as instructing BS110b that UE 120 is attempting to connect to BS110b for 5G NR voice fallback, or automatically attempting to connect to BS110c (before returning to BS110a) when the handover or redirection fails, thereby reducing the delay in establishing voice calls.

[0075] Figure 4 This is a diagram illustrating, for example, an exemplary process 400 performed by a UE. Exemplary process 400 illustrates an example of a UE (e.g., UE 120) performing voice fallback for 5G NR.

[0076] like Figure 4As shown, in some aspects, processing 400 may include receiving a command from a first BS associated with a 5G NR RAT for mobility from that 5G NR RAT to a second RAT (block 410). For example, a UE (e.g., using a receive processor 258, a controller / processor 280, a memory 282, or other examples, or combinations thereof) may receive a command from the first BS associated with the 5G NR RAT for mobility from that 5G NR RAT to the second RAT, as described above.

[0077] like Figure 4 As shown, in some aspects, processing 400 may include: determining that the mobility command is for voice fallback (block 420). For example, the UE (e.g., using a receive processor 258, a transmit processor 264, a controller / processor 280, a memory 282, or other examples, or combinations thereof) may determine that the mobility command is for voice fallback, as described above.

[0078] like Figure 4 As shown, in some aspects, processing 400 may include: sending an RRC connection request communication to a second BS associated with the second RAT, at least in part based on the determination that the mobility command is for voice fallback, to attempt to establish a communication connection with the second BS for voice fallback (block 430). For example, the UE (e.g., using transmit processor 264, controller / processor 280, memory 282, or other examples, or combinations thereof) may send an RRC connection request communication to a second BS associated with the second RAT, at least in part based on the determination that the mobility command is for voice fallback, to attempt to establish a communication connection with the second BS for voice fallback, as described above.

[0079] Processing 400 may include other aspects, such as any single aspect or any combination of the aspects described below or in combination with one or more other aspects of processing described elsewhere in this document.

[0080] In a first aspect, the second RAT includes an LTE RAT or a 3G RAT. In a second aspect, determining that a mobility command is for voice fallback, either alone or in combination with the first aspect, includes: determining that the mobility command is for voice fallback based at least in part on identifying a voice fallback indication included in the mobility command. In a third aspect, either alone or in combination with one or more of the first or second aspects, the mobility command includes: MobilityFromNRCommand NR RRC communication, HandoverPreparationInformation LTE RRC communication, RRCLease NR RRC communication, source RNC to target RNC transparent container, or UTRAN RRC connection request communication.

[0081] In a fourth aspect, determining that the mobility command is for voice fallback, either alone or in combination with one or more of the first to third aspects, includes: determining that the mobility command is for voice fallback based at least in part on receiving the mobility command when establishing a voice call, or the UE's ability to implement a VoNR voice call. In a fifth aspect, the RRC connection request communication indicates a voice call as a cause value, either alone or in combination with one or more of the first to fourth aspects.

[0082] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, processing 400 includes: detecting a failed attempt to establish a communication connection with the second BS; and, based at least in part on the detection of the failed attempt to establish a communication connection with the second BS, and at least in part on the receipt of a mobility command, attempting to establish a communication connection with a third BS associated with the second RAT. In a seventh aspect, either alone or in combination with one or more of the first to sixth aspects, the first BS and the second BS are different BSs, the 5G NR RAT is associated with a cell of the first BS, and the second RAT is associated with a cell of the second BS.

[0083] In the eighth aspect, either individually or in combination with one or more of the first to seventh aspects, the first BS, the second BS, and the third BS are the same BS, the 5G NR RAT is associated with a first cell of the same BS, the second RAT is associated with a second cell of the same BS, and the second RAT is associated with a third cell of the same BS. In the ninth aspect, either individually or in combination with one or more of the first to eighth aspects, the first BS, the second BS, and the third BS are different BSs, the 5G NR RAT is associated with a cell of the first BS, the second RAT is associated with a cell of the second BS, and the second RAT is associated with a cell of the third BS.

[0084] In the tenth aspect, either alone or in combination with one or more of the first to ninth aspects, the second BS and the third BS are different BSs, the second RAT is associated with a cell of the second BS, and the second RAT is associated with a cell of the third BS. In the eleventh aspect, either alone or in combination with one or more of the first to tenth aspects, the second BS and the third BS are the same BS, the second RAT is associated with a first cell of the same BS, and the second RAT is associated with a second cell of the third BS.

[0085] In the twelfth aspect, either alone or in combination with one or more of the first to eleventh aspects, the first BS and the third BS are the same BS, the 5G NR RAT is associated with a first cell of the same BS, and the second RAT is associated with a second cell of the same BS. In the thirteenth aspect, either alone or in combination with one or more of the first to twelfth aspects, the first BS and the second BS are the same BS, the 5G NR RAT is associated with a first cell of the same BS, and the second RAT is associated with a second cell of the same BS.

[0086] Although Figure 4 An exemplary box for handling 400 is shown, but in some respects, it differs from... Figure 4 Compared to what is described in [the original text], process 400 may include additional boxes, fewer boxes, different boxes, or boxes arranged differently. Alternatively or concurrently, two or more boxes in process 400 may be executed in parallel.

[0087] Figure 5 This is a diagram illustrating an exemplary process 500 performed, for example, by a BS. Exemplary process 500 illustrates a scenario where a BS (e.g., BS110a or BS110b) performs operations associated with voice fallback for 5G NR.

[0088] like Figure 5 As shown, in some aspects, process 500 may include: determining that a UE communicatively connected to the BS is establishing a voice call, wherein the BS is associated with a 5G NR RAT (block 510). For example, the BS (e.g., using transmit processor 220, receive processor 238, controller / processor 240, memory 242, or other examples, or combinations thereof) may determine that a UE communicatively connected to the BS is establishing a voice call, as described above. In some aspects, the BS is associated with a 5G NR RAT.

[0089] like Figure 5As shown, in some aspects, processing 500 may include: sending a command for mobility from a 5G NR RAT to a second RAT, at least in part based on the determination that the UE is establishing a voice call, wherein the mobility command includes a voice fallback indication (block 520). For example, the BS (e.g., using transmit processor 220, controller / processor 240, memory 242, or other examples, or combinations thereof) may send the command for mobility from a 5G NR RAT to a second RAT, at least in part based on the determination that the UE is establishing a voice call, as described above. In some aspects, the mobility command includes a voice fallback indication.

[0090] Process 500 may include additional aspects, such as any single aspect and / or any combination of the aspects described below and / or in combination with one or more other aspects of the processes described elsewhere in this document.

[0091] In a first aspect, the second RAT includes an LTE RAT or a 3G RAT. In a second aspect, sending the mobility command, either alone or in combination with the first aspect, includes sending the mobility command to at least one of another BS or the UE. In a third aspect, either alone or in combination with one or more of the first or second aspects, the mobility command includes at least one of the following: a transparent container included in an S1AP communication sent to another BS, a RANAP communication sent to the other BS, a HandoverPreparationInformationLTE RRC communication sent to the other BS, a MobilityFromNRCommand NR RRC communication sent to the UE, a HandoverCommand LTE RRC communication sent to the UE, an RRCRelease NR RRC communication sent to the UE, a source RNC to target RNC transparent container, or a UTRAN RRC connection request communication.

[0092] Although Figure 5 An exemplary box for handling 500 is shown, but in some respects, it differs from... Figure 5 Compared to what is described in [the original text], processing 500 may include additional boxes, fewer boxes, different boxes, or boxes arranged differently. Alternatively or concurrently, two or more boxes in processing 500 may be executed in parallel.

[0093] The above disclosure provides illustrations and descriptions, but is not exhaustive, nor does it limit these aspects to the precise form disclosed. Modifications and variations may be made based on the above disclosure, or they may be derived from practice in these areas.

[0094] As used herein, the term "component" is intended to be interpreted broadly as hardware, firmware, or a combination of hardware and software. As used herein, a "processor" is implemented using hardware, firmware, or a combination of hardware and software. As used herein, the phrase "based on" is intended to be interpreted broadly as meaning "at least partially based on," unless otherwise explicitly stated.

[0095] As used in this article, the phrase referring to "at least one of" a list item means any combination of these items, including a single member. For example, "at least one of a, b, or c" is intended to cover: a, b, c, ab, ac, bc, and abc.

[0096] The various exemplary logics, logic blocks, modules, circuits, and algorithmic processes described in conjunction with the aspects disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. This interchangeability between hardware and software is typically described in relation to their functionality and illustrated using the various exemplary components, blocks, modules, circuits, and processes described above. Whether this functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0097] Hardware and data processing means for implementing the various exemplary logics, logic blocks, modules, and circuits described in conjunction with the aspects disclosed herein may be implemented or executed using a general-purpose single-chip or multi-chip 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 device, discrete hardware component, or any combination thereof for performing the functions described herein. The general-purpose processor may be a microprocessor, or it may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, several microprocessors, one or more microprocessors combined with a DSP core, or any other such architecture. In some aspects, specific processing and methods may be performed by circuitry specific to a given function.

[0098] In one or more aspects, the described functions can be implemented using hardware, digital electronic circuits, computer software, firmware (including the structures disclosed herein and their structural equivalents), or any combination thereof. Aspects of the subject matter described herein can also be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a computer storage medium, for execution by a data processing apparatus or to control the operation of the data processing apparatus.

[0099] When implemented using software, functionality can be stored on a computer-readable medium or transmitted via one or more instructions or code on a computer-readable medium. Processing of the methods or algorithms disclosed herein can be implemented using processor-executable software modules residing on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of computer programs from one place to another. Storage media can be any available medium accessible to a computer. For example, but not limitingly, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other medium capable of storing desired program code in the form of instructions or data structures and accessible to a computer. Furthermore, any connection can be appropriately referred to as a computer-readable medium. As used herein, disks and optical discs include compact optical discs (CDs), laser discs, optical discs, digital versatile optical discs (DVDs), floppy disks, and Blu-ray discs, wherein disks typically magnetically copy data, while optical discs optically copy data using lasers. Combinations of the above should also be included within the scope of protection of computer-readable media. Furthermore, the operation of a method or algorithm may exist as code and instruction sets or any combination thereof on machine-readable and computer-readable media, which may be incorporated into a computer program product.

[0100] Various modifications to the aspects described in this disclosure will be apparent to those skilled in the art, and the general principles defined herein may also be applied to other aspects without departing from the spirit or scope of this disclosure. Therefore, the invention is not limited to the aspects shown herein, but is consistent with the broadest scope of the disclosure, principles, and novel features disclosed herein.

[0101] Furthermore, those skilled in the art should readily understand that, for the convenience of describing the accompanying drawings, the terms “upper” and “lower” are sometimes used, indicating relative positions corresponding to the orientation of the figures on a properly oriented page, and may not reflect the correct orientation of any implemented device.

[0102] Some features described in this specification in the context of different aspects can also be combined into a single aspect for implementation. Conversely, various features described in the context of a single aspect can also be implemented individually or in any suitable sub-combination in multiple aspects. Furthermore, although some features are described above as working in a certain combination (even if initially claimed to be so), in some cases, one or more features in the claimed combination can be separated from that combination, which can be for a sub-combination or a variation of the sub-combination.

[0103] Similarly, although operations are described in a specific order in the accompanying drawings, this should not be construed as meaning that these operations need to be performed in the specific or sequential order shown, or that all shown operations must be performed, in order to obtain the desired result. Furthermore, the drawings schematically depict one or more exemplary processes in the form of flowcharts. However, other operations not described may be incorporated into the schematically shown example processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between the shown operations. In some environments, multitasking and parallel processing are advantageous. Moreover, the division of system components in the aspects described above should not be construed as requiring such division in all aspects; rather, it should be understood that the described program components and systems can generally be integrated together into a single software product or packaged into multiple software products. Additionally, other aspects also fall within the scope of the appended claims. In some cases, the actions set forth in the claims can be performed in a different order and still obtain the desired result.

Claims

1. A method for wireless communication performed by a device of a user equipment (UE), comprising: Mobility commands, including a voiceFallbackIndication element, are received from a first base station (BS) associated with a fifth-generation new radio (5G NR) radio access technology (RAT). The voiceFallbackIndication element indicates that the mobility command is for voice fallback from the 5G NR RAT to a Long Term Evolution (LTE) RAT. The mobility command is included in a Radio Resource Control (RRC) release communication, which is an RRC Release NR RRC communication; The RRC connection request communication includes an indication of a reason value for the voice call being used in the RRC connection request communication; and The RRC connection request communication is sent to the second BS associated with the LTE RAT and at least in part based on the command received including the voiceFallbackIndication information element of the mobility, for attempting to establish a communication connection with the second BS for voice fallback.

2. The method according to claim 1, wherein, A voice call initiated by a mobile station (MO) or terminated by a mobile station (MT) is established between the UE and the first BS.

3. The method according to claim 1, wherein, The cause value indicated for the voice call enables the second BS to prioritize resource allocation to the UE.

4. The method according to claim 1, wherein, The command to receive the mobility includes: The mobility command is received when the voice call is established.

5. The method according to claim 1, further comprising: Establish the voice call with the first BS.

6. The method according to claim 5, wherein, The voice call is either a voice call initiated by the mobile station (MO) or a voice call terminated by the mobile station (MT).

7. The method according to claim 1, wherein, The voice call is a VoNR (VoNR) voice call.

8. The method according to claim 1, further comprising: The detection is associated with the failure to establish a communication connection with the second BS in order to perform voice fallback; as well as At least in part, based on the detection of the aforementioned failure, an attempt is made to communicate with a third BS.

9. The method according to claim 1, further comprising: The detection is associated with the failure to establish a communication connection with the second BS in order to perform voice fallback; as well as At least in part, communication with the second BS is retried based on the detection of the failure.

10. A user equipment (UE) for wireless communication, comprising: Memory; as well as One or more processors coupled to the memory, the one or more processors being configured to: Mobility commands, including a voiceFallbackIndication element, are received from a first base station (BS) associated with a fifth-generation new radio (5G NR) radio access technology (RAT). The voiceFallbackIndication element indicates that the mobility command is for voice fallback from the 5G NR RAT to a Long Term Evolution (LTE) RAT. The mobility command is included in a Radio Resource Control (RRC) release communication, which is an RRC Release NR RRC communication; The RRC connection request communication includes an indication of a reason value for the voice call being used in the RRC connection request communication; and The RRC connection request communication is sent to the second BS associated with the LTE RAT and at least in part based on the command received including the voiceFallbackIndication information element of the mobility, for attempting to establish a communication connection with the second BS for voice fallback.

11. The UE according to claim 10, wherein, A voice call initiated by a mobile station (MO) or terminated by a mobile station (MT) is established between the UE and the first BS.

12. The UE according to claim 10, wherein, The cause value indicated for the voice call enables the second BS to prioritize resource allocation to the UE.

13. The UE according to claim 10, wherein, The one or more processors for receiving commands regarding the mobility are configured to: The mobility command is received when the voice call is established.

14. The UE of claim 10, wherein the one or more processors are further configured to: Establish the voice call with the first BS.

15. The UE according to claim 14, wherein, The voice call is either a voice call initiated by the mobile station (MO) or a voice call terminated by the mobile station (MT).

16. The UE according to claim 10, wherein, The voice call is a VoNR (VoNR) voice call.

17. A non-transitory computer-readable medium storing an instruction set for wireless communication, the instruction set comprising: One or more instructions, when executed by one or more processors of a user equipment (UE), cause the UE to perform the following operations: Mobility commands, including a voiceFallbackIndication element, are received from a first base station (BS) associated with a fifth-generation new radio (5G NR) radio access technology (RAT). The voiceFallbackIndication element indicates that the mobility command is for voice fallback from the 5G NR RAT to a Long Term Evolution (LTE) RAT. The mobility command is included in a Radio Resource Control (RRC) release communication, which is an RRC Release NR RRC communication; The RRC connection request communication includes an indication of a reason value for the voice call being used in the RRC connection request communication; and The RRC connection request communication is sent to the second BS associated with the LTE RAT and at least in part based on the command received including the voiceFallbackIndication information element of the mobility, for attempting to establish a communication connection with the second BS for voice fallback.

18. The non-transitory computer-readable medium according to claim 17, wherein, A voice call initiated by a mobile station (MO) or terminated by a mobile station (MT) is established between the UE and the first BS.

19. The non-transitory computer-readable medium according to claim 17, wherein, The one or more instructions that cause the UE to receive the mobility command cause the UE to perform the following operations: The mobility command is received when the voice call is established.

20. The non-transitory computer-readable medium according to claim 17, wherein, The one or more instructions also cause the UE to perform the following operations: Establish the voice call with the first BS.

21. The non-transitory computer-readable medium according to claim 20, wherein, The voice call is either a voice call initiated by the mobile station (MO) or a voice call terminated by the mobile station (MT).

22. The non-transitory computer-readable medium according to claim 17, wherein, The cause value indicated for the voice call enables the second BS to prioritize resource allocation to the UE.

23. The non-transitory computer-readable medium according to claim 17, wherein, The voice call is a VoNR (VoNR) voice call.

24. An apparatus for wireless communication, comprising: A unit for receiving a mobility command, including a voiceFallbackIndication information element, from a first base station (BS) associated with a fifth-generation new radio (5G NR) radio access technology (RAT), the voiceFallbackIndication information element indicating that the mobility command is for voice fallback from the 5G NR RAT to the Long Term Evolution (LTE) RAT. The mobility command is included in a Radio Resource Control (RRC) release communication, which is an RRC Release NR RRC communication; A unit for including an indication in an RRC connection request communication that a voice call is a cause value for the RRC connection request communication; and A unit for sending the RRC connection request communication to a second BS associated with the LTE RAT and at least in part based on receiving a command for mobility including the voiceFallbackIndication information element, for attempting to establish a communication connection with the second BS for voice fallback.

25. The apparatus according to claim 24, wherein, A voice call initiated by a mobile station (MO) or terminated by a mobile station (MT) is established between a user equipment (UE) and the first BS.

26. The apparatus according to claim 24, wherein, The unit for receiving the mobility command includes: A unit for receiving the mobility command when establishing the voice call.

27. The apparatus of claim 24, further comprising: A unit for establishing the voice call with the first BS.

28. The apparatus according to claim 27, wherein, The voice call is either a voice call initiated by the mobile station (MO) or a voice call terminated by the mobile station (MT).

29. The apparatus according to claim 24, wherein, The voice call is a VoNR (VoNR) voice call.

30. The apparatus according to claim 24, wherein, The cause value indicated for the voice call enables the second BS to prioritize resource allocation to the device.

Images