WO2021237589A1

WO2021237589A1 - A method to accelerate ue return 5g from 4g

Info

Publication number: WO2021237589A1
Application number: PCT/CN2020/092987
Authority: WO
Inventors: Fojian ZHANG; Yuankun ZHU; Chaofeng HUI; Jian Li; Hao Zhang
Original assignee: Qualcomm Incorporated
Priority date: 2020-05-28
Filing date: 2020-05-28
Publication date: 2021-12-02

Abstract

Wireless communication techniques that include techniques for an accelerated UE return to 5G (SA) network service from 4G network service are discussed. A UE may transmit an indication that a RSRP associated with a first base station is less than a threshold. The transmitted indication may be transmitted to the first base station. The UE may receive an indication of one or more second base stations that may be used by the UE for wireless communication. The received indication may be associated with the transmitted indication, and the received indication may be received from the first base station. The UE may trigger a registration procedure with at least one of the indicated one or more second base stations. Other aspects and features are also claimed and described.

Description

A METHOD TO ACCELERATE UE RETURN 5G FROM 4G

TECHNICAL FIELD

Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to techniques for an accelerated UE return to 5G (SA) network service from 4G network service. Certain aspects of the technology discussed below can enable and provide enhanced communication features and techniques for communication systems, including high performance, high reliability, low latency, low complexity, power-efficient device operations, and aiding devices to discover, select, recover, and use network service.

INTRODUCTION

Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, and the like. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources.

A wireless communication network may include a number of base stations or node Bs that can support communication for a number of user equipments (UEs) . A UE may communicate with a base station via downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.

A base station may transmit data and control information on the downlink to a UE and/or may receive data and control information on the uplink from the UE. On the downlink, a transmission from the base station may encounter interference due to transmissions from neighbor base stations or from other wireless radio frequency (RF) transmitters. On the uplink, a transmission from the UE may encounter interference from uplink transmissions of other UEs communicating with the neighbor base stations or from other wireless RF transmitters. This interference may degrade performance on both the downlink and uplink.

As the demand for mobile broadband access continues to increase, the possibilities of interference and congested networks grows with more UEs accessing the long-range wireless communication networks and more short-range wireless systems being deployed in communities. Research and development continue to advance wireless technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.

BRIEF SUMMARY OF SOME EMBODIMENTS

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

In one aspect of the disclosure, a method of wireless communication is provided. For example, a method can include transmitting, by a UE, an indication that a reference signal reference power (RSRP) associated with a first base station is less than a threshold, wherein the transmitted indication is transmitted to the first base station. The method can also include receiving, by the UE, an indication of one or more second base stations that may be used by the UE for wireless communication, wherein the received indication is associated with the transmitted indication, and wherein the received indication is received from the first base station. The method can further include triggering, by the UE, a registration procedure with at least one of the one or more second base stations.

In another aspect of the disclosure, an apparatus configured for wireless communication is provided. For example, the apparatus can include means for transmitting an indication that a reference signal reference power (RSRP) associated with a first base station is less than a threshold, wherein the transmitted indication is transmitted to the first base station. The apparatus can also include means for receiving an indication of one or more second base stations that may be used by a UE for wireless communication, wherein the received indication is associated with the transmitted indication, and wherein the received indication is received from the first base station. The apparatus can further include means for triggering a registration procedure with at least one of the one or more second base stations.

In an additional aspect of the disclosure, a non-transitory computer-readable medium having program code recorded thereon is provided. The program code can include program code executable by a computer for causing the computer to transmit an indication that a reference signal reference power (RSRP) associated with a first base station is less than a threshold, wherein the transmitted indication is transmitted to the first base station. The program code can also include program code executable by the computer for causing the computer to receive an indication of one or more second base stations that may be used by a UE for wireless communication, wherein the received indication is associated with the transmitted indication, and wherein the received indication is received from the first base station. The program code can further include program code executable by the computer for causing the computer to trigger a registration procedure with at least one of the one or more second base stations.

In another aspect of the disclosure, an apparatus configured for wireless communication is provided. The apparatus includes at least one processor, and a memory coupled to the processor. The at least one processor can be configured to transmit an indication that a reference signal reference power (RSRP) associated with a first base station is less than a threshold, wherein the transmitted indication is transmitted to the first base station. The at least one processor can also be configured to receive an indication of one or more second base stations that may be used by a UE for wireless communication, wherein the received indication is associated with the transmitted indication, and wherein the received indication is received from the first base station. The at least one processor can be further configured to trigger a registration procedure with at least one of the one or more second base stations.

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

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the present disclosure may be realized by reference to the following drawings. In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label with a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

FIG. 1 is a block diagram illustrating details of a wireless communication system according to some aspects of the present disclosure.

FIG. 2 is a block diagram conceptually illustrating a design of a base station and a UE configured according to some aspects of the present disclosure.

FIG. 3 is a block diagram illustrating a method for an accelerated UE return to 5G (SA) network service from 4G network service according to some aspects of the present disclosure.

FIG. 4 is a diagram illustrating operations performed by a UE to return to 5G (SA) network service from non-5G (SA) network service, e.g., 4G/LTE network service, according to some aspects of the present disclosure.

FIG. 5 is a block diagram conceptually illustrating a design of a UE configured according to some aspects of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with the appended drawings, is intended as a description of various configurations and is not intended to limit the scope of the disclosure. Rather, the detailed description includes specific details for the purpose of providing a thorough understanding of the inventive subject matter. It will be apparent to those skilled in the art that these specific details are not required in every case and that, in some instances, well-known structures and components are shown in block diagram form for clarity of presentation.

This disclosure relates generally to providing or participating in communication as between two or more wireless devices in one or more wireless communications systems, also referred to as wireless communications networks. In various embodiments, the techniques and apparatus may be used for wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks, GSM networks, 5 ^th Generation (5G) or new radio (NR) networks (sometimes referred to as “5G NR” networks/systems/devices) , as well as other communications networks. As described herein, the terms “networks” and “systems” may be used interchangeably.

A CDMA network, for example, may implement a radio technology such as universal terrestrial radio access (UTRA) , cdma2000, and the like. UTRA includes wideband-CDMA (W-CDMA) and low chip rate (LCR) . CDMA2000 covers IS-2000, IS-95, and IS-856 standards.

A TDMA network may, for example implement a radio technology such as GSM. 3GPP defines standards for the GSM EDGE (enhanced data rates for GSM evolution) radio access network (RAN) , also denoted as GERAN. GERAN is the radio component of GSM/EDGE, together with the network that joins the base stations (for example, the Ater and Abis interfaces) and the base station controllers (A interfaces, etc. ) . The radio access network represents a component of a GSM network, through which phone calls and packet data are routed from and to the public switched telephone network (PSTN) and Internet to and from subscriber handsets, also known as user terminals or user equipments (UEs) . A mobile phone operator's network may comprise one or more GERANs, which may be coupled with Universal Terrestrial Radio Access Networks (UTRANs) in the case of a UMTS/GSM network. An operator network may also include one or more LTE networks, and/or one or more other networks. The various different network types may use different radio access technologies (RATs) and radio access networks (RANs) .

An OFDMA network may implement a radio technology such as evolved UTRA (E-UTRA) , IEEE 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and the like. UTRA, E-UTRA, and Global System for Mobile Communications (GSM) are part of universal mobile telecommunication system (UMTS) . In particular, long term evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided from an organization named “3rd Generation Partnership Project” (3GPP) , and cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . These various radio technologies and standards are known or are being developed. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications associations that aims to define a globally applicable third generation (3G) mobile phone specification. 3GPP long term evolution (LTE) is a 3GPP project which was aimed at improving the universal mobile telecommunications system (UMTS) mobile phone standard. The 3GPP may define specifications for the next generation of mobile networks, mobile systems, and mobile devices. The present disclosure is concerned with the evolution of wireless technologies from LTE, 4G, 5G, NR, and beyond with shared access to wireless spectrum between networks using a collection of new and different radio access technologies or radio air interfaces.

5G networks contemplate diverse deployments, diverse spectrum, and diverse services and devices that may be implemented using an OFDM-based unified, air interface. To achieve these goals, further enhancements to LTE and LTE-A are considered in addition to development of the new radio technology for 5G NR networks. The 5G NR will be capable of scaling to provide coverage (1) to a massive Internet of things (IoTs) with an ultra-high density (e.g., ～1M nodes/km ²) , ultra-low complexity (e.g., ～10s of bits/sec) , ultra-low energy (e.g., ～10+ years of battery life) , and deep coverage with the capability to reach challenging locations; (2) including mission-critical control with strong security to safeguard sensitive personal, financial, or classified information, ultra-high reliability (e.g., ～99.9999%reliability) , ultra-low latency (e.g., ～ 1 ms) , and users with wide ranges of mobility or lack thereof; and (3) with enhanced mobile broadband including extreme high capacity (e.g., ～ 10 Tbps/km ²) , extreme data rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates) , and deep awareness with advanced discovery and optimizations.

5G NR devices, networks, and systems may be implemented to use optimized OFDM-based waveform features. These features may include scalable numerology and transmission time intervals (TTIs) ; a common, flexible framework to efficiently multiplex services and features with a dynamic, low-latency time division duplex (TDD) /frequency division duplex (FDD) design; and advanced wireless technologies, such as massive multiple input, multiple output (MIMO) , robust millimeter wave (mmWave) transmissions, advanced channel coding, and device-centric mobility. Scalability of the numerology in 5G NR, with scaling of subcarrier spacing, may efficiently address operating diverse services across diverse spectrum and diverse deployments. For example, in various outdoor and macro coverage deployments of less than 3GHz FDD/TDD implementations, subcarrier spacing may occur with 15 kHz, for example over 1, 5, 10, 20 MHz, and the like bandwidth. For other various outdoor and small cell coverage deployments of TDD greater than 3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHz bandwidth. For other various indoor wideband implementations, using a TDD over the unlicensed portion of the 5 GHz band, the subcarrier spacing may occur with 60 kHz over a 160 MHz bandwidth. Finally, for various deployments transmitting with mmWave components at a TDD of 28 GHz, subcarrier spacing may occur with 120 kHz over a 500MHz bandwidth.

The scalable numerology of 5G NR facilitates scalable TTI for diverse latency and quality of service (QoS) requirements. For example, shorter TTI may be used for low latency and high reliability, while longer TTI may be used for higher spectral efficiency. The efficient multiplexing of long and short TTIs to allow transmissions to start on symbol boundaries. 5G NR also contemplates a self-contained integrated subframe design with uplink/downlink scheduling information, data, and acknowledgement in the same subframe. The self-contained integrated subframe supports communications in unlicensed or contention-based shared spectrum, adaptive uplink/downlink that may be flexibly configured on a per-cell basis to dynamically switch between uplink and downlink to meet the current traffic needs.

For clarity, certain aspects of the apparatus and techniques may be described below with reference to exemplary LTE implementations or in an LTE-centric way, and LTE terminology may be used as illustrative examples in portions of the description below; however, the description is not intended to be limited to LTE applications. Indeed, the present disclosure is concerned with shared access to wireless spectrum between networks using different radio access technologies or radio air interfaces, such as those of 5G NR.

Moreover, it should be understood that, in operation, wireless communication networks adapted according to the concepts herein may operate with any combination of licensed or unlicensed spectrum depending on loading and availability. Accordingly, it will be apparent to one of skill in the art that the systems, apparatus and methods described herein may be applied to other communications systems and applications than the particular examples provided.

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

FIG. 1 shows wireless network 100 for communication according to some embodiments. Wireless network 100 may, for example, comprise a 5G wireless network. As appreciated by those skilled in the art, components appearing in FIG. 1 are likely to have related counterparts in other network arrangements including, for example, cellular-style network arrangements and non-cellular-style-network arrangements (e.g., device to device or peer to peer or ad hoc network arrangements, etc. ) .

Wireless network 100 illustrated in FIG. 1 includes a number of base stations 105 and other network entities. A base station may be a station that communicates with the UEs and may also be referred to as an evolved node B (eNB) , a next generation eNB (gNB) , an access point, and the like. Each base station 105 may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to this particular geographic coverage area of a base station and/or a base station subsystem serving the coverage area, depending on the context in which the term is used. In implementations of wireless network 100 herein, base stations 105 may be associated with a same operator or different operators (e.g., wireless network 100 may comprise a plurality of operator wireless networks) , and may provide wireless communications using one or more of the same frequencies (e.g., one or more frequency bands in licensed spectrum, unlicensed spectrum, or a combination thereof) as a neighboring cell. In some examples, an individual base station 105 or UE 115 may be operated by more than one network operating entity. In other examples, each base station 105 and UE 115 may be operated by a single network operating entity.

A base station may provide communication coverage for a macro cell or a small cell, such as a pico cell or a femto cell, and/or other types of cell. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a pico cell, would generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a femto cell, would also generally cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG) , UEs for users in the home, and the like) . A base station for a macro cell may be referred to as a macro base station. A base station for a small cell may be referred to as a small cell base station, a pico base station, a femto base station or a home base station. In the example shown in FIG. 1,

base stations

105d and 105e are regular macro base stations, while base stations 105a-105c are macro base stations enabled with one of 3 dimension (3D) , full dimension (FD) , or massive MIMO. Base stations 105a-105c take advantage of their higher dimension MIMO capabilities to exploit 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. Base station 105f is a small cell base station which may be a home node or portable access point. A base station may support one or multiple (e.g., two, three, four, and the like) cells.

Wireless network 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, the base stations may have different frame timing, and transmissions from different base stations may not be aligned in time. In some scenarios, networks may be enabled or configured to handle dynamic switching between synchronous or asynchronous operations.

UEs 115 are dispersed throughout the wireless network 100, and each UE may be stationary or mobile. It should be appreciated that, although a mobile apparatus is commonly referred to as user equipment (UE) in standards and specifications promulgated by the 3rd Generation Partnership Project (3GPP) , such apparatus may also be referred to by those skilled in the art as a mobile station (MS) , a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT) , a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, a gaming device, an augmented reality device, vehicular component device/module, or some other suitable terminology. Within the present document, a “mobile” apparatus or UE need not necessarily have a capability to move, and may be stationary. Some non-limiting examples of a mobile apparatus, such as may comprise embodiments of one or more of UEs 115, include a mobile, a cellular (cell) phone, a smart phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a laptop, a personal computer (PC) , a notebook, a netbook, a smart book, a tablet, and a personal digital assistant (PDA) . A mobile apparatus may additionally be an “Internet of things” (IoT) or “Internet of everything” (IoE) device such as an automotive or other transportation vehicle, a satellite radio, a global positioning system (GPS) device, a logistics controller, a drone, a multi-copter, a quad-copter, a smart energy or security device, a solar panel or solar array, municipal lighting, water, or other infrastructure; industrial automation and enterprise devices; consumer and wearable devices, such as eyewear, a wearable camera, a smart watch, a health or fitness tracker, a mammal implantable device, gesture tracking device, medical device, a digital audio player (e.g., MP3 player) , a camera, a game console, etc.; and digital home or smart home devices such as a home audio, video, and multimedia device, an appliance, a sensor, a vending machine, intelligent lighting, a home security system, a smart meter, etc. In one aspect, a UE may be a device that includes a Universal Integrated Circuit Card (UICC) . In another aspect, a UE may be a device that does not include a UICC. In some aspects, UEs that do not include UICCs may also be referred to as IoE devices. UEs 115a-115d of the embodiment illustrated in FIG. 1 are examples of mobile smart phone-type devices accessing wireless network 100 A UE may also be a machine specifically configured for connected communication, including machine type communication (MTC) , enhanced MTC (eMTC) , narrowband IoT (NB-IoT) and the like. UEs 115e-115k illustrated in FIG. 1 are examples of various machines configured for communication that access wireless network 100.

A mobile apparatus, such as UEs 115, may be able to communicate with any type of the base stations, whether macro base stations, pico base stations, femto base stations, relays, and the like. In FIG. 1, a lightning bolt (e.g., communication link) indicates wireless transmissions between a UE and a serving base station, which is a base station designated to serve the UE on the downlink and/or uplink, or desired transmission between base stations, and backhaul transmissions between base stations. UEs may operate as base stations or other network nodes in some scenarios. Backhaul communication between base stations of wireless network 100 may occur using wired and/or wireless communication links.

In operation at wireless network 100, base stations 105a-105c serve

UEs

115a and 115b using 3D beamforming and coordinated spatial techniques, such as coordinated multipoint (CoMP) or multi-connectivity. Macro base station 105d performs backhaul communications with base stations 105a-105c, as well as small cell, base station 105f. Macro base station 105d also transmits multicast services which are subscribed to and received by

UEs

115c and 115d. Such multicast services may include mobile television or stream video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or gray alerts.

Wireless network 100 of embodiments supports mission critical communications with ultra-reliable and redundant links for mission critical devices, such UE 115e, which is a drone. Redundant communication links with UE 115e include from

macro base stations

105d and 105e, as well as small cell base station 105f. Other machine type devices, such as UE 115f (thermometer) , UE 115g (smart meter) , and UE 115h (wearable device) may communicate through wireless network 100 either directly with base stations, such as small cell base station 105f, and macro base station 105e, or in multi-hop configurations by communicating with another user device which relays its information to the network, such as UE 115f communicating temperature measurement information to the smart meter, UE 115g, which is then reported to the network through small cell base station 105f. Wireless network 100 may also provide additional network efficiency through dynamic, low-latency TDD/FDD communications, such as in a vehicle-to-vehicle (V2V) mesh network between UEs 115i-115k communicating with macro base station 105e.

FIG. 2 shows a block diagram of a design of a base station 105 and a UE 115, which may be any of the base stations and one of the UEs in FIG. 1. For a restricted association scenario (as mentioned above) , base station 105 may be small cell base station 105f in FIG. 1, and UE 115 may be UE 115c or 115D operating in a service area of base station 105f, which in order to access small cell base station 105f, would be included in a list of accessible UEs for small cell base station 105f. Base station 105 may also be a base station of some other type. As shown in FIG. 2, base station 105 may be equipped with antennas 234a through 234t, and UE 115 may be equipped with antennas 252a through 252r for facilitating wireless communications.

At base station 105, transmit processor 220 may receive data from data source 212 and control information from controller/processor 240. The control information may be for the physical broadcast channel (PBCH) , physical control format indicator channel (PCFICH) , physical hybrid-ARQ (automatic repeat request) indicator channel (PHICH) , physical downlink control channel (PDCCH) , enhanced physical downlink control channel (EPDCCH) , MTC physical downlink control channel (MPDCCH) , etc. The data may be for the PDSCH, etc. Transmit processor 220 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. Transmit processor 220 may also generate reference symbols, e.g., for the primary synchronization signal (PSS) and secondary synchronization signal (SSS) , and cell-specific reference signal. Transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to modulators (MODs) 232a through 232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM, etc. ) to obtain an output sample stream. Each modulator 232 may additionally or alternatively process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators 232a through 232t may be transmitted via antennas 234a through 234t, respectively.

At UE 115, the antennas 252a through 252r may receive the downlink signals from base station 105 and may provide received signals to demodulators (DEMODs) 254a through 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc. ) to obtain received symbols. MIMO detector 256 may obtain received symbols from demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. Receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 115 to data sink 260, and provide decoded control information to controller/processor 280.

On the uplink, at UE 115, transmit processor 264 may receive and process data (e.g., for the physical uplink shared channel (PUSCH) ) from data source 262 and control information (e.g., for the physical uplink control channel (PUCCH) ) from controller/processor 280. Transmit processor 264 may also generate reference symbols for a reference signal. The symbols from transmit processor 264 may be precoded by TX MIMO processor 266 if applicable, further processed by modulators 254a through 254r (e.g., for SC-FDM, etc. ) , and transmitted to base station 105. At base station 105, the uplink signals from UE 115 may be received by antennas 234, processed by demodulators 232, detected by MIMO detector 236 if applicable, and further processed by receive processor 238 to obtain decoded data and control information sent by UE 115. Processor 238 may provide the decoded data to data sink 239 and the decoded control information to controller/processor 240.

Controllers/

processors

240 and 280 may direct the operation at base station 105 and UE 115, respectively. Controller/processor 240 and/or other processors and modules at base station 105 and/or controller/processor 280 and/or other processors and modules at UE 115 may perform or direct the execution of various processes for the techniques described herein, such as to perform or direct the execution illustrated in FIG. 3, and/or other processes for the techniques described herein.

Memories

242 and 282 may store data and program codes for base station 105 and UE 115, respectively. Scheduler 244 may schedule UEs for data transmission on the downlink and/or uplink.

Wireless communications systems operated by different network operating entities (e.g., network operators) may share spectrum. In some instances, a network operating entity may be configured to use an entirety of a designated shared spectrum for at least a period of time before another network operating entity uses the entirety of the designated shared spectrum for a different period of time. Thus, in order to allow network operating entities use of the full designated shared spectrum, and in order to mitigate interfering communications between the different network operating entities, certain resources (e.g., time) may be partitioned and allocated to the different network operating entities for certain types of communication.

For example, a network operating entity may be allocated certain time resources reserved for exclusive communication by the network operating entity using the entirety of the shared spectrum. The network operating entity may also be allocated other time resources where the entity is given priority over other network operating entities to communicate using the shared spectrum. These time resources, prioritized for use by the network operating entity, may be utilized by other network operating entities on an opportunistic basis if the prioritized network operating entity does not utilize the resources. Additional time resources may be allocated for any network operator to use on an opportunistic basis.

Access to the shared spectrum and the arbitration of time resources among different network operating entities may be centrally controlled by a separate entity, autonomously determined by a predefined arbitration scheme, or dynamically determined based on interactions between wireless nodes of the network operators.

In some cases, UE 115 and base station 105 may operate in a shared radio frequency spectrum band, which may include licensed or unlicensed (e.g., contention-based) frequency spectrum. In an unlicensed frequency portion of the shared radio frequency spectrum band, UEs 115 or base stations 105 may traditionally perform a medium-sensing procedure to contend for access to the frequency spectrum. For example, UE 115 or base station 105 may perform a listen before talk (LBT) procedure such as a clear channel assessment (CCA) prior to communicating in order to determine whether the shared channel is available. A CCA may include an energy detection procedure to determine whether there are any other active transmissions. For example, a device may infer that a change in a received signal strength indicator (RSSI) of a power meter indicates that a channel is occupied. Specifically, signal power that is concentrated in a certain bandwidth and exceeds a predetermined noise floor may indicate another wireless transmitter. A CCA also may include detection of specific sequences that indicate use of the channel. For example, another device may transmit a specific preamble prior to transmitting a data sequence. In some cases, an LBT procedure may include a wireless node adjusting its own backoff window based on the amount of energy detected on a channel and/or the acknowledge/negative-acknowledge (ACK/NACK) feedback for its own transmitted packets as a proxy for collisions.

A UE, such as UE 115, may obtain wireless network service from various wireless communication networks using various types of radio access technology (RAT) . A network may be associated with one or more base stations that utilize the same RAT utilized by the associated network. The wireless communication network may provide wireless network service to a UE through associated base stations.

Of the various wireless communication RATs commercially available throughout the world, 5G NR technology exhibits many improvements over legacy non-5G NR technology as well as over technology that is a mixture of 5G NR technology and legacy non-5G NR technology. In some aspects, a RAT that includes only 5G NR technology may be referred to as a RAT that operates in a standalone (SA) mode of 5G NR. Such a RAT may be referred to as 5G (SA) . According to some aspects, a RAT that includes a mixture of 5G NR technology and non-5G NR technology, such as 4G or a particular type of LTE technology, may be referred to as a RAT that operates in a non-standalone (NSA) mode of 5G NR. Such a RAT may be referred to as 5G (NSA) . As an example, a 5G (NSA) network may be a network that includes a primary/anchor base station that utilizes 4G/LTE technology and also includes a secondary base station that utilizes 5G (SA) technology. In some aspects, non-5G NR technology may refer to any technology that does not include 5G NR. For example, non-5G technology may include LTE (or a particular type of LTE, such as LTE Advanced (LTE-A) , LTE in unlicensed spectrum (LTE-U) , etc. ) , 4G, WCDMA, CDMA2000, GSM, TD-SCDMA, IS-95, to name only a few.

Because of the advantages of 5G (SA) technology, a UE may first attempt to register for network services on a wireless network associated with 5G (SA) . If the UE is unable to get 5G (SA) network service, the UE may attempt to register itself for service on a wireless network associated with another type of technology, such as a 5G (NSA) network or a 4G/LTE network. For example, a UE may revert to a non-5G (SA) network when signal quality associated with a 5G (SA) network is weak, e.g., because interference or a 5G (SA) base station is far away, when 5G (SA) network service is lost, which may be lost for a variety of reasons, or when registration with a 5G (SA) network fails, which may fail for a variety of reasons, to name only a few reasons. However, when 5G (SA) network service becomes available while the UE is receiving non-5G (SA) network service, a UE may attempt to get 5G (SA) network service to make use of the many advantages of 5G (SA) technology.

Prior techniques for returning a UE to 5G (SA) network service when the UE is receiving non-5G (SA) network service, e.g., 5G (NSA) network service or 4G/LTE network service, yield unfavorable operations in some instances. For example, prior techniques may cause a UE to remain in a 4G/LTE network for a long period of time even after 5G (SA) network service becomes available. As an example, prior techniques may cause a UE to remain in a 4G/LTE network when good 4G/LTE network service is received by the UE. As a result, a UE may not quickly return to a preferred 5G (SA) network and instead remain in a 4G/LTE network for a longer-than-necessary amount of time. This often results in poor user experience with the UE.

Aspects of the disclosure aid a UE in accelerating its return to a 5G (SA) network from a non-5G (SA) network, such as a 5G (NSA) network or a 4G/LTE network. FIG. 3, as an example, shows a block diagram illustrating a method for an accelerated UE return to 5G (SA) network service from 4G network service according to some aspects of the present disclosure. Aspects of method 300 may be implemented with various other aspects of this disclosure described with respect to FIGS. 1-2 and 4-5, such as a mobile device/UE. For example, with reference to FIG. 2, controller/processor 280 of UE 115 may control UE 115 to perform method 300.

The example blocks of method 300 will also be described with respect to UE 115 as illustrated in FIG. 5. FIG. 5 is a block diagram conceptually illustrating a design of a UE configured according to some aspects of the present disclosure. UE 115 may include various structures, hardware, and components, such as those illustrated for UE 115 of FIG. 2. For example, UE 115 includes controller/processor 280, which operates to execute logic or computer instructions stored in memory 282. The controller/processor 280 can also control components of UE 115 that provide the features and functionality of UE 115. UE 115, under control of controller/processor 280, transmits and receives signals via wireless radios 501a-r and antennas 252a-r. Wireless radios 501a-r include various components and hardware, as illustrated in FIG. 2 for UE 115, including modulator/demodulators 254a-r, MIMO detector 256, receive processor 258, transmit processor 264, and TX MIMO processor 266. The controller/processor 280 can be provided with digital signals obtained from sampling received analog wireless signals for purposes of controlling communication operations.

FIG. 3 illustrates a method 300 that may be performed by a wireless communication device, such as a UE 115. Method 300 includes, at block 302, transmitting, by a UE, an indication that a reference signal reference power (RSRP) associated with a first base station of a first network is less than a threshold. In some aspects, the transmitted indication may be transmitted to the first base station. At block 304, method 300 includes receiving, by the UE, an indication of one or more second base stations of a second network that may be used by the UE for wireless communication. In some aspects, the received indication may be associated with the transmitted indication. In additional aspects, the received indication may be received from the first base station. Method 300 also includes, at block 306, triggering, by the UE, a registration procedure with at least one of the one or more second base stations to register the UE for service in the second network. The actions shown at

blocks

302, 304, and 306 of method 300 may be a subset of the overall operations performed by a UE to return to a 5G (SA) network from a non-5G (SA) network. The relationship between the actions shown at

blocks

302, 304, and 306 of method 300 and other operations that are performed by a UE to return to a 5G (SA) network from a non-5G (SA) network may become more evident from a discussion of the overall operations performed by a UE to return to a 5G (SA) network from a non-5G (SA) network.

FIG. 4 is a diagram illustrating operations performed by a UE to return to 5G (SA) network service from non-5G (SA) network service, e.g., 4G/LTE network service, according to some aspects of the present disclosure. FIG. 4 shows a UE 402, a 4G/LTE base station 404, and a 5G (SA) base station 406. A 5G (SA) base station 406 may refer to a base station that utilizes 5G (SA) RAT and that is part of a 5G (SA) network. A 4G/LTE base station 404 may refer to a base station that utilizes 4G/LTE RAT. 4G/LTE base station 404 may be part of a 4G/LTE network or part of a 5G (NSA) network.

As illustrated at block 410 of FIG. 4, UE 402 may have a radio resource control (RRC) connection with 4G/LTE base station 404. For example, UE 402 may have a RRC connection with a network associated with 4G/LTE base station 404 to transmit/receive information to/from 4G/LTE base station 404, e.g., to upload and/or download information. Various operations may be performed by UE 402 while it has an RRC connection with 4G/LTE base station 404. For example, UE 402 may receive, detect, and/or measure a RSRP associated with 4G/LTE base station 404.

In some aspects, UE 402 may make a decision 411 based on processing of the RSRP associated with 4G/LTE base station 404. For example, UE 402 may make a decision 411 as to whether or not the RSRP associated with 4G/LTE base station 404 is less than, equal to, or greater than a threshold.

In some aspects, the threshold used for decision 411 may be adjustable. For example, as illustrated in FIG. 4, the threshold used for decision 411 may include an “A2 threshold” component and a “COMPENSATION” component. In some aspects, the A2 threshold component may refer to a baseline or fixed threshold component of the threshold used for decision 411. According to some aspects, the fixed A2 threshold component may be preset by a wireless communication specification, such as a 3GPP specification, to a value and may not be adjusted from that preset value. According to some additional aspects, the A2 threshold may refer to a fixed threshold component that is preset by the network associated with 4G/LTE base station 404. In some aspects, 4G/LTE base station 404 may send the A2 threshold value to UE 402 in an RRC reconfiguration message. In some aspects, the COMPENSATION component of the threshold used for decision 411 may be an adjustable threshold value that is combined with the A2 threshold to arrive at the threshold used for decision 411. For example, the COMPENSATION component may be subtracted from the A2 threshold to arrive at a lower threshold to be used for decision 411. In another example, the COMPENSATION component may be added to the A2 threshold to arrive at a higher threshold to be used for decision 411. In some aspects of the disclosure, a value of the COMPENSATION component may be adjusted from a first value to a second value that is different than the first value. As an example, in some aspects of the disclosure, the value of the COMPENSATION component may be adjusted from a first value to a second value after the UE determines at decision 411 that the RSRP associated with 4G/LTE base station 404 is greater than (or equal to) the threshold currently used for decision 411.

According to some aspects, UE 402 may determine at decision 411 that the RSRP associated with 4G/LTE base station 404 is less than (or equal to) the threshold used at decision 411. In some aspects, upon determining at decision 411 that the RSRP associated with 4G/LTE base station 404 is less than (or equal to) the threshold used at decision 411, UE 402 may transmit a measurement report message 412 to 4G/LTE base station 404. According to some aspects, the transmitted measurement report message 412 may be and/or may include an indication that the RSRP associated with 4G/LTE base station 404 is less than (or equal to) the threshold used for decision 411. In some aspects, the transmitted indication may be an “Event A2” indication, as illustrated in FIG. 4 as being included in measurement report message 412. According to some aspects of the disclosure, the foregoing actions, such as the transmitting of the measurement report message 412, may correspond to actions shown at block 302 of FIG. 3, such as the transmitting, by a UE, of an indication that a RSRP associated with a first base station is less than a threshold. For example, in some aspects, the transmitted measurement report message 412 and/or the Event A2 indication may correspond to the indication that a RSRP associated with a first base station is less than a threshold, as shown at block 302 of FIG. 3. In additional aspects, the RSRP associated with 4G/LTE base station 404 may correspond to the RSRP shown at block 302 of FIG. 3, and the threshold used at decision 411 may correspond to the threshold shown at block 302 of FIG. 3. According to some aspects of the disclosure, the first base station shown at block 302 of FIG. 3 may not be a 5G (SA) base station. For example, in some aspects, the first base station shown at block 302 of FIG. 3 may be 4G/LTE base station 404, which may be part of a 4G/LTE network or part of a 5G (NSA) network. According to some aspects, 4G/LTE base station 404 may be referred to as a primary/anchor base station.

In some aspects of the disclosure, measurement report message 412 may be associated with the fixed A2 threshold component of the threshold used for decision 411. According to some aspects, the transmitted measurement report message 412 may be and/or may include an indication that the RSRP associated with 4G/LTE base station 404 is less than (or equal to) the fixed A2 threshold component of the threshold used for decision 411. According to some aspects, inclusion of the “Event A2” indication in the measurement report message 412 may indicate that the RSRP associated with 4G/LTE base station 404 is less than the fixed A2 threshold component of the threshold used for decision 411.

According to some aspects, in response to receiving the measurement report message 412, 4G/LTE base station 404 may send a RRC reconfiguration message 413 to UE 402. UE 402 may receive the RRC reconfiguration message 413 sent by 4G/LTE base station 404. In some aspects, the received RRC reconfiguration message 413 may itself be and/or may include an indication of one or more 5G (SA) base stations that may be used by UE 402 for wireless communication. In some aspects, the received indication may be a 5G (SA) neighbor cell (NC) list, as illustrated in FIG. 4 as being included in RRC reconfiguration message 413. According to some aspects of the disclosure, the foregoing actions, such as the receiving of the RRC reconfiguration message 413, may correspond to actions shown at block 304 of FIG. 3, such as the receiving, by the UE, an indication of one or more second base stations that may be used by the UE for wireless communication. For example, in some aspects, the received RRC reconfiguration message 413 and/or the 5G (SA) NC list may correspond to the indication of one or more second base stations that may be used by the UE for wireless communication, as shown at block 304 of FIG. 3. According to some aspects, 5G (SA) base station 406 may be indicated as a second base station that may be used by UE 402 for wireless communication. For example, 5G (SA) base station 406 may be included in the 5G (SA) NC list. In some aspects of the disclosure, one or more 5G (SA) base stations, including 5G (SA) base station 406, may correspond to the one or more second base stations shown at block 304 of FIG. 3. According to some aspects, each of the one or more second base stations shown at block 304 of FIG. 3 may be a 5G (SA) base station. In some aspects, the received RRC reconfiguration message 413 and/or the 5G (SA) NC list may be associated with, e.g., based on or responsive to, the transmitted measurement report message 412 and/or the Event A2 indication.

In some aspects of the disclosure, UE 402 may store the 5G (SA) NC list, as shown at block 414 of FIG. 4. For example, UE 402 may store the 5G (SA) NC list in memory within UE 402. In other words, with reference to FIG. 3, UE 402 may store the indication of one or more second base stations that may be used by the UE for wireless communication.

In some aspects, UE 402 may receive an RRC release message 415 from 4G/LTE base station 404. For example, UE 402 may receive the RRC release message 415 after receiving the RRC reconfiguration message 413 and/or storing the 5G (SA) NC list. After receiving the RRC release message 415, UE 402 may enter an RRC idle state, as shown at block 416 of FIG. 4. In some aspects, upon entering the RRC idle state 416, UE 402 may no longer have a RRC connection with a network associated with 4G/LTE base station 404.

According to some aspects of the disclosure, after entering the RRC idle state 416, UE 402 may search candidate 5G (SA) base stations indicated in the 5G (SA) NC list to identify a 5G (SA) base station that UE 402 may use for wireless communication, as shown at block 417 of FIG. 4. In some aspects of the disclosure, UE 402 may consider numerous factors to select a candidate 5G (SA) base station indicated in the 5G (SA) NC list as the 5G (SA) base station that the UE 402 should use for wireless communication. According to some aspects, some factors that may be considered may include signal strength associated with signals received from various 5G (SA) base stations and/or whether a particular 5G (SA) base station is on a list of base stations that should not be used by UE 402 for wireless communication, e.g., a forbidden list.

In some aspects of the disclosure, UE 402 may trigger a registration procedure with 5G (SA) base station 406 to register UE 402 in a 5G (SA) network so that UE 402 may receive 5G (SA) network service. As indicated previously, 5G (SA) base station 406 may be a candidate 5G (SA) base station included in the 5G (SA) NC list. In addition, 5G (SA) base station 406 may be the 5G (SA) base station UE 402 selected to use for wireless communication after considering all the factors considered at block 417 during the search of candidate 5G (SA) base stations indicated in the 5G (SA) NC list. According to some aspects of the disclosure, the foregoing actions, such as the triggering of the registration procedure with 5G (SA) base station 406, may correspond to actions shown at block 306 of FIG. 3, such as the triggering, by the UE, of a registration procedure with at least one of the one or more second base stations. For example, in some aspects, the triggered registration procedure with 5G (SA) base station 406 shown in FIG. 4 may correspond to the triggered registration procedure shown at block 306 of FIG. 3. In addition, 5G (SA) base station 406 may correspond to the at least one of the one or more second base stations shown at block 306 of FIG. 3.

In some aspects, the triggered registration procedure with 5G (SA) base station 406 may include various operations. For example, as illustrated in FIG. 4, in one aspect of the disclosure, the triggered registration procedure may include UE 402 transmitting a registration request message 418 to 5G (SA) base station 406. The registration procedure may also include UE 402 receiving from 5G (SA) base station 406 a registration accept message 419.

As illustrated in FIG. 4, in some aspects of the disclosure, the measurement report message 412 that includes the Event A2 indication may be transmitted by UE 402 while UE 402 has a RRC connection with 4G/LTE base station 404. Similarly, RRC reconfiguration message 413 that includes 5G (SA) NC list may be received by UE 402 while UE 402 has a RRC connection with 4G/LTE base station 404. In other words, with reference to FIG. 3, the transmitted indication may be transmitted and the received indication may be received while UE 402 has a RRC connection with the 4G/LTE base station 404.

As illustrated in FIG. 4, according to some aspects of the disclosure, the registration procedure with 5G (SA) base station 406 may be triggered after the RRC connection with the 4G/LTE base station 404 is released and/or UE 402 has entered an idle state. In other words, with reference to FIG. 3, the registration procedure with the at least one of the one or more second base stations may be triggered after the RRC connection with the first base station is released and/or the UE has entered an idle state.

In some aspects, techniques for an accelerated UE return to 5G (SA) network service from 4G network service may include a UE transmitting an indication that a reference signal reference power (RSRP) associated with a first base station is less than a threshold, wherein the transmitted indication is transmitted to the first base station. Techniques for an accelerated UE return to 5G (SA) network service from 4G network service may also include a UE receiving an indication of one or more second base stations that may be used by the UE for wireless communication, wherein the received indication is associated with the transmitted indication, and wherein the received indication is received from the first base station. Techniques for an accelerated UE return to 5G (SA) network service from 4G network service may further include a UE triggering a registration procedure with at least one of the one or more second base stations.

Techniques for an accelerated UE return to 5G (SA) network service from 4G network service may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.

In a first aspect, the threshold may be adjustable.

In a second aspect, alone or in combination with the first aspect, the transmitted indication may be transmitted and the received indication may be received while the UE has a radio resource control (RRC) connection with the first base station.

In a third aspect, alone or in combination with one or more of the first and second aspects, the registration procedure with the at least one of the one or more second base stations may be triggered after the RRC connection with the first base station is released and the UE has entered an idle state.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, the first base station may not be a 5G (SA) base station.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, each of the second base stations may be a 5G (SA) base station.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the UE may store the indication of one or more second base stations that may be used by the UE for wireless communication.

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

The functional blocks and modules described herein (e.g., the functional blocks and modules in FIG. 2) may comprise processors, electronics devices, hardware devices, electronics components, logical circuits, memories, software codes, firmware codes, etc., or any combination thereof. In addition, features discussed herein may be implemented via specialized processor circuitry, via executable instructions, and/or combinations thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm processing (e.g., the logical blocks in FIG. 3) described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure. Skilled artisans will also readily recognize that the order or combination of components, methods, or interactions that are described herein are merely examples and that the components, methods, or interactions of the various aspects of the present disclosure may be combined or performed in ways other than those illustrated and described herein.

The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein may be implemented or performed with 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 herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

Features of a method or algorithm described in connection with the disclosure herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. Computer-readable storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, a connection may be properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, or digital subscriber line (DSL) , then the coaxial cable, fiber optic cable, twisted pair, or DSL, are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , hard disk, solid state disk, and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

As used herein, including in the claims, the term “and/or, ” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination. Also, as used herein, including in the claims, “or” as used in a list of items prefaced by “at least one of” indicates a disjunctive list such that, for example, a list of “at least one of A, B, or C” means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) or any of these in any combination thereof.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

A method of wireless communication, comprising:

transmitting, by a user equipment (UE) , an indication that a reference signal reference power (RSRP) associated with a first base station is less than a threshold, wherein the transmitted indication is transmitted to the first base station;

receiving, by the UE, an indication of one or more second base stations that may be used by the UE for wireless communication, wherein the received indication is associated with the transmitted indication, and wherein the received indication is received from the first base station; and

triggering, by the UE, a registration procedure with at least one of the one or more second base stations.
The method of claim 1, wherein the threshold is adjustable.
The method of claim 1, wherein the transmitted indication is transmitted and the received indication is received while the UE has a radio resource control (RRC) connection with the first base station.
The method of claim 3, wherein the registration procedure with the at least one of the one or more second base stations is triggered after the RRC connection with the first base station is released and the UE has entered an idle state.
The method of claim 1, wherein the first base station is not a fifth generation (5G) standalone (SA) base station.
The method of claim 1, wherein each of the second base stations is a fifth generation (5G) standalone (SA) base station.
The method of claim 1, further comprising:

storing the indication of one or more second base stations that may be used by the UE for wireless communication.
The method of any combination of claims 1-7.
An apparatus configured for wireless communication, comprising:

means for transmitting an indication that a reference signal reference power (RSRP) associated with a first base station is less than a threshold, wherein the transmitted indication is transmitted to the first base station;

means for receiving an indication of one or more second base stations that may be used by a user equipment (UE) for wireless communication, wherein the received indication is associated with the transmitted indication, and wherein the received indication is received from the first base station; and

means for triggering a registration procedure with at least one of the one or more second base stations.
The apparatus of claim 9, wherein the threshold is adjustable.
The apparatus of claim 9, wherein the transmitted indication is transmitted and the received indication is received while the UE has a radio resource control (RRC) connection with the first base station.
The apparatus of claim 11, wherein the registration procedure with the at least one of the one or more second base stations is triggered after the RRC connection with the first base station is released and the UE has entered an idle state.
The apparatus of claim 9, wherein the first base station is not a fifth generation (5G) standalone (SA) base station.
The apparatus of claim 9, wherein each of the second base stations is a fifth generation (5G) standalone (SA) base station.
The apparatus of claim 9, further comprising means for storing the indication of one or more second base stations that may be used by the UE for wireless communication.
The apparatus of any combination of claims 9-15.
A non-transitory computer-readable medium having program code recorded thereon, the program code comprising:

program code executable by a computer for causing the computer to transmit an indication that a reference signal reference power (RSRP) associated with a first base station is less than a threshold, wherein the transmitted indication is transmitted to the first base station;

program code executable by the computer for causing the computer to receive an indication of one or more second base stations that may be used by a user equipment (UE) for wireless communication, wherein the received indication is associated with the transmitted indication, and wherein the received indication is received from the first base station; and

program code executable by the computer for causing the computer to trigger a registration procedure with at least one of the one or more second base stations.
The non-transitory computer-readable medium of claim 17, wherein the threshold is adjustable.
The non-transitory computer-readable medium of claim 17, wherein the transmitted indication is transmitted and the received indication is received while the UE has a radio resource control (RRC) connection with the first base station.
The non-transitory computer-readable medium of claim 19, wherein the registration procedure with the at least one of the one or more second base stations is triggered after the RRC connection with the first base station is released and the UE has entered an idle state.
The non-transitory computer-readable medium of claim 17, wherein the first base station is not a fifth generation (5G) standalone (SA) base station.
The non-transitory computer-readable medium of claim 17, wherein each of the second base stations is a fifth generation (5G) standalone (SA) base station.
The non-transitory computer-readable medium of claim 17, further comprising program code executable by the computer for causing the computer to store the indication of one or more second base stations that may be used by the UE for wireless communication.
The non-transitory computer-readable medium of any combination of claims 17-23.
An apparatus configured for wireless communication, the apparatus comprising:

at least one processor; and

a memory coupled to the at least one processor,

wherein the at least one processor is configured to:

transmit an indication that a reference signal reference power (RSRP) associated with a first base station is less than a threshold, wherein the transmitted indication is transmitted to the first base station;

receive an indication of one or more second base stations that may be used by a user equipment (UE) for wireless communication, wherein the received indication is associated with the transmitted indication, and wherein the received indication is received from the first base station; and

trigger a registration procedure with at least one of the one or more second base stations.
The apparatus of claim 25, wherein the threshold is adjustable.
The apparatus of claim 25, wherein the transmitted indication is transmitted and the received indication is received while the UE has a radio resource control (RRC) connection with the first base station.
The apparatus of claim 27, wherein the registration procedure with the at least one of the one or more second base stations is triggered after the RRC connection with the first base station is released and the UE has entered an idle state.
The apparatus of claim 25, wherein the first base station is not a fifth generation (5G) standalone (SA) base station.
The apparatus of claim 25, wherein each of the second base stations is a fifth generation (5G) standalone (SA) base station.
The apparatus of claim 25, wherein the at least one processor is further configured to store the indication of one or more second base stations that may be used by the UE for wireless communication.
The apparatus of any combination of claims 25-31.