WO2021237578A1

WO2021237578A1 - Battery-level based 5g background search

Info

Publication number: WO2021237578A1
Application number: PCT/CN2020/092964
Authority: WO
Inventors: Yuankun ZHU; Fojian ZHANG; Chaofeng HUI; Jian Li; Hao Zhang; Pan JIANG; Yi Liu; Gang Liu; Zhuoqi XU
Original assignee: Qualcomm Incorporated
Priority date: 2020-05-28
Filing date: 2020-05-28
Publication date: 2021-12-02

Abstract

A user equipment (UE) may be configured to perform battery-level based background search. In some aspects, the UE may determine a battery attribute value of the user equipment, determine an interval period and a duration period based on the battery attribute value, and performing, during a wake up cycle of a reduced power mode, a plurality of cell searches to connect to a cell, a second cell search of the plurality of cell searches performed for the duration period and succeeding a first cell search of the plurality of cell searches by the interval period.

Description

BATTERY-LEVEL BASED 5G BACKGROUND SEARCH

BACKGROUND

Technical Field

The present disclosure relates generally to communication systems, and more particularly, wireless devices configured to perform a battery-level based background search.

Introduction

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. 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, and time division synchronous code division multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR) . 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT) ) , and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB) , massive machine type communications (mMTC) , and ultra reliable low latency communications (URLLC) . Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in 5G NR technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

SUMMARY

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

In an aspect, the disclosure provides a method of wireless communication at a user equipment. The method may include determining a battery attribute value of the user equipment connected to a first radio access network (RAN) , determining, based on the battery attribute value, an interval period and a duration period for a cell search in a second RAN, and performing, by the user equipment during a wake up cycle of a reduced power mode, a plurality of cell searches to connect to a cell in the second RAN, a second cell search of the plurality of cell searches performed for the duration period and succeeding a first cell search of the plurality of cell searches by the interval period.

The disclosure also provides an apparatus (e.g., a user equipment (UE) ) including a memory storing computer-executable instructions and at least one processor configured to execute the computer-executable instructions to perform at least one of the above methods, an apparatus including means for performing at least one of the above methods, and a non-transitory computer-readable medium storing computer-executable instructions for performing at least the above methods.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network.

FIG. 2Ais a diagram illustrating an example of a first 5G/NR frame.

FIG. 2B is a diagram illustrating an example of DL channels within a 5G/NR subframe.

FIG. 2C is a diagram illustrating an example of a second 5G/NR frame.

FIG. 2D is a diagram illustrating an example of UL channels within a 5G/NR subframe.

FIG. 3 is a diagram illustrating an example of a base station and user equipment (UE) in an access network.

FIG. 4 is a diagram illustrating example communications and components of base stations and UEs.

FIG. 5 is a flowchart of a method of wireless communication.

FIG. 6 is a conceptual data flow diagram illustrating the data flow between different means/components in an example user equipment.

FIG. 7 is a diagram illustrating an example of a hardware implementation for an user equipment employing a processing system.

DETAILED DESCRIPTION

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

A network deployment for a network operator may include cells for a most recent radio access technology (RAT) as well as legacy cells operating according to a different RAT. The legacy cells may provide support for older UEs that are still active on a first radio access network (RAN) of the network. Further, UEs capable of connecting to a second RAN of the network via the most recent RAT may also be capable of connecting to the first RAN via one or more legacy RATs. For example, due to phased network deployment, there may be a geographical area where only a legacy RAT is available. Further, while connected to the legacy RAT, a UE may perform a cell search to facilitate connection to a more recent RAT. For instance, when a UE is camping on a 2G, 3G, or 4G cell in idle mode, the UE may perform a cell search to connect to a 5G NR cell. But continuously or semi-persistently performing a cell search can significantly drain the battery power of the UE and/or disrupt a low power mode of a UE implemented to conserve the battery power of the UE, thereby causing inefficient resource consumption and a less favorable user experience. Conversely, failure to connect to a more recent RAT may limit a UE to wireless services having data throughput and reliability capabilities not suited for modern UE usage.

The present disclosure addresses one or more of the above issues by providing, in one aspect, a background cell search procedure where a UE, connected to a network using a legacy RAT, determines an interval period and a duration period for a cell search based on a battery attribute value, and performs a plurality of cell searches to connect to a network using a more recent RAT based on the duration period and the interval period. By modifying the parameters of a background cell search in view of the battery attribute of the UE, the present solution balances power consumption by a UE and a preference for the UE to connect to a more recent RAN (i.e., eagerness of the UE to connect to a more preferable network) .

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems on a chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Accordingly, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100. The wireless communications system (also referred to as a wireless wide area network (WWAN) ) includes base stations 102, UEs 104, an Evolved Packet Core (EPC) 160, and another core network 190 (e.g., a 5G Core (5GC) ) . The base stations 102 may include macrocells (high power cellular base station) and/or small cells (low power cellular base station) . The macrocells include base stations. The small cells include femtocells, picocells, and microcells. In an aspect, a UE 104 may include a battery 140 and a background search component 141 configured to implement battery-level based background searches for base station cells 102, as described herein. As used herein, in some aspects, a “battery” may refer to any energy storage device that can used in a UE to provide power. The background search component 141 may include a cell search profile 142 defining configuration parameters for implementing battery-level based background searches, an attribute detection component 143 configured to determine an attribute value of the battery 140, a configuration component 144 configured to determine search parameters based upon the attribute value, and a search component 145 configured to perform cell searches in accordance with the determined search parameters, in order to facilitate connection via a preferred RAT without unduly compromising the user experience of the UE via poor battery life or insufficient wireless access. As used herein, a “cell search” may refer to a procedure for a UE 104 to acquire time and frequency synchronization with a cell of a base station 102 and to detect the physical layer Cell ID of the cell. In addition, the UE 104 may include a mode management component 146 configured to manage sleep and wake cycles of a low power mode of the UE 104.

The base stations 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through first backhaul links 132 (e.g., S1 interface) . The base stations 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN) ) may interface with core network 190 through second backhaul links 184. In addition to other functions, the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages. The base stations 102 may communicate directly or indirectly (e.g., through the EPC 160 or core network 190) with each other over third backhaul links 134 (e.g., X2 interface) . The third backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102' may have a coverage area 110' that overlaps the coverage area 110 of one or more macro base stations 102. A network that includes both small cell and macrocells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) . The communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base stations 102 /UEs 104 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL) . The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .

Certain UEs 104 may communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) . D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 /AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell 102' may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102' may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102', employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.

A base station 102, whether a small cell 102' or a large cell (e.g., macro base station) , may include and/or be referred to as an eNB, gNodeB (gNB) , or another type of base station. Some base stations, such as gNB 180 may operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and/or near mmW frequencies in communication with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW /near mmW radio frequency band (e.g., 3 GHz –300 GHz) has extremely high path loss and a short range. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range. The base station 180 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate the beamforming.

The base station 180 may transmit a beamformed signal to the UE 104 in one or more transmit directions 182'. The UE 104 may receive the beamformed signal from the base station 180 in one or more receive directions 182” . The UE 104 may also transmit a beamformed signal to the base station 180 in one or more transmit directions. The base station 180 may receive the beamformed signal from the UE 104 in one or more receive directions. The base station 180 /UE 104 may perform beam training to determine the best receive and transmit directions for each of the base station 180 /UE 104. The transmit and receive directions for the base station 180 may or may not be the same. The transmit and receive directions for the UE 104 may or may not be the same.

The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

The core network 190 may include a Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may be in communication with a Unified Data Management (UDM) 196. The AMF 192 is the control node that processes the signaling between the UEs 104 and the core network 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 195. The UPF 195 provides UE IP address allocation as well as other functions. The UPF 195 is connected to the IP Services 197. The IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services.

The base station may include and/or be referred to as a gNB, Node B, eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology. The base station 102 provides an access point to the EPC 160 or core network 190 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc. ) . The UE 104 may also be referred to as a station, a mobile station, 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, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

FIGS. 2A-2D illustrates example diagrams 200, 230, 250, and 280 illustrating examples structures that may be used for wireless communication by the base station 102 and the UE 104, e.g., for 5G NR communication. FIG. 2A is a diagram 200 illustrating an example of a first subframe within a 5G/NR frame structure. FIG. 2B is a diagram 230 illustrating an example of DL channels within a 5G/NR subframe. FIG. 2C is a diagram 250 illustrating an example of a second subframe within a 5G/NR frame structure. FIG. 2D is a diagram 280 illustrating an example of UL channels within a 5G/NR subframe. The 5G/NR frame structure may be FDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for either DL or UL, or may be TDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for both DL and UL. In the examples provided by FIGS. 2A, 2C, the 5G/NR frame structure is assumed to be TDD, with subframe 4 being configured with slot format 28 (with mostly DL) , where D is DL, U is UL, and X is flexible for use between DL/UL, and subframe 3 being configured with slot format 34 (with mostly UL) . While

subframes

3, 4 are shown with slot formats 34, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. UEs are configured with the slot format (dynamically through DL control information (DCI) , or semi-statically/statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI) . Note that the description infra applies also to a 5G/NR frame structure that is TDD.

Other wireless communication technologies may have a different frame structure and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms) . Each subframe may include one or more time slots. Subframes may also include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols. The symbols on DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also referred to as single carrier frequency-division multiple access (SC-FDMA) symbols) (for power limited scenarios; limited to a single stream transmission) . The number of slots within a subframe is based on the slot configuration and the numerology. For slot configuration 0, different numerologies μ 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots, respectively, per subframe. For slot configuration 1, different numerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, per subframe. Accordingly, for slot configuration 0 and numerology μ, there are 14 symbols/slot and 2μ slots/subframe. The subcarrier spacing and symbol length/duration are a function of the numerology. The subcarrier spacing may be equal to 2 ^μ*15 kHz, where μ is the numerology 0 to 5. As such, the numerology μ=0 has a subcarrier spacing of 15 kHz and the numerology μ=5 has a subcarrier spacing of 480 kHz. The symbol length/duration is inversely related to the subcarrier spacing. FIGS. 2A-2D provide an example of slot configuration 0 with 14 symbols per slot and numerology μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

A resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs) ) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include demodulation RS (DM-RS) (indicated as R _x for one particular configuration, where 100x is the port number, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS) , beam refinement RS (BRRS) , and phase tracking RS (PT-RS) .

FIG. 2B illustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) , each CCE including nine RE groups (REGs) , each REG including four consecutive REs in an OFDM symbol. A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE 104 to determine subframe/symbol timing and a physical layer identity. A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DM-RS. The physical broadcast channel (PBCH) , which carries a master information block (MIB) , may be logically grouped with the PSS and SSS to form a synchronization signal (SS) /PBCH block. The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN) . The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and paging messages.

As illustrated in FIG. 2C, some of the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH) . The PUSCH DM-RS may be transmitted in the first one or two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. The UE may transmit sounding reference signals (SRS) . The SRS may be transmitted in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

FIG. 2D illustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and HARQ ACK/NACK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.

FIG. 3 is a block diagram of a base station 310 in communication with a UE 350 in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller/processor 375. The controller/processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller/processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs) , RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression /decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs) , error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) . The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a respective spatial stream for transmission.

At the UE 350, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) . The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller/processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller/processor 359 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DL transmission by the base station 310, the controller/processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression /decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 350. IP packets from the controller/processor 375 may be provided to the EPC 160. The controller/processor 375 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

With respect to the UE 350, at least one of the TX processor 368, the RX processor 356, and the controller/processor 359 may be configured to perform aspects in connection with the background search component 141 of FIG. 1.

As described herein, a UE connected to a network via a legacy RAT may endeavor to connect to a network via a more advanced RAT. However, performing a cell search for cells implementing the more advanced RAT can significantly drain the battery power of the UE and/or disrupt a low power mode of the UE implemented to conserve its battery power. As such, UEs may implement a battery-level based background search to acquire wireless services offered by more recent RATs without unduly compromising a user experience by way of inadequate battery performance.

The present disclosure provides techniques for efficiently performing cell searches in view of a current battery attribute value and operation mode of a UE. For example, a UE may determine a current battery level of the UE. As used herein, in some aspects, “battery level” may refer to a state of charge of a battery. Further, the UE may determine, based on the battery level, a duration period defining the length of a cell search on one or more frequency bands and an interval period determining how often to perform a cell search over one or more frequency bands of a plurality of frequency bands. In addition, the UE may perform a plurality of cell searches based on the interval period and the duration period while in a wake cycle of a low power mode of the UE. For example, while in the wake mode, the UE may perform first cell search for the duration period over a first frequency, and a second cell search for the duration period over the second frequency band at a period in time that succeeds the end of the first cell search by the interval period.

Referring to FIGS. 4-7, in one non limiting aspect, a system 400 is configured to provide battery-level based background search for wireless access, such as 5G NR, according to some aspects.

FIG. 4 is a diagram illustrating example communications and components of base stations and UEs. As illustrated in FIG. 4, the system 400 may include a UE 402 connected to a first RAT base station 404 of a first RAT via a connection 406, and a plurality of second RAT base stations 408 (1) - (N) of a second RAT. In some aspects, the second RAT may be more advanced or preferred with respect to the first RAT. For example, the first RAT base station 404 may provide a legacy cell of a first RAT, such as a 2G cell, a 3G cell, or a 4G cell, and the second RAT base stations 408 (1) - (N) may provide 5G NR cells. As described in detail herein, the UE 402 may be configured to operate in multiple radio access technologies (RATs) . As such, the UE 402 may endeavor to acquire access from one of the second RAT base stations 408 (1) - (N) even when connected to the first RAT base station 404. Alternatively, in some aspects, the UE may perform a handover from the first RAT base station 404 to one of the second RAT base stations 408 (1) - (N) .

As illustrated in FIG. 1, the second RAT base stations 408 (1) - (N) may transmit synchronization transmissions (ST) 410 (1) - (N) for reception by UEs, such as the UE 402. In some aspects, the ST 410 may be a synchronization signal block (SSB) . Further, each ST 410 may include a PSS, a SSS, and a PBCH. In some aspects, the UE 402 may detect a cell and the SSB reception timing by using a ST 410, and measure the RSRP for the ST 410 at a predetermined time based on the obtained information. From the measurement result, the UE 402 can identify the ST 410 with the strongest signal strength as the best beam for the UE 402. In some aspects, the UE 402 may send a communication (e.g., a PRACH) to the second RAT base station 408 associated with the best beam in order to trigger initial access by the UE 402 to the second RAT base station 408, and subsequently acquire wireless service from the second RAT base station 408.

Further, the UE 402 may include the battery 140 and the background search component 141. The battery 140 may power the UE 402. As described above with respect to FIG. 1, the background search component 141 may include the cell search profile 142, the attribute detection component 143, the configuration component 144, the search component 145, and the mode management component 146. In addition, the UE 402 may include the reception component 412 and the transmitter component 414. The reception component 412 may include, for example, a radio frequency (RF) receiver for receiving the signals described herein. The transmitter component 414 may include, for example, an RF transmitter for transmitting the signals described herein. In an aspect, the reception component 412 and the transmitter component 414 may be co-located in a transceiver.

Initially, the UE 402 may be in an idle mode and camped on the first RAT base station 404, which may be considered a serving cell. Further, the UE 402 may operate in a discontinuous reception mode (DRX) to reduce power consumption, i.e., conserve the battery power of the battery 140. As used herein, DRX may refer to a technique that permits a UE to power down components of the internal circuitry of the UE when it is in the idle mode. When performing DRX, the UE 402 may discontinuously monitor the connection 406 with the first RAT base station 404. In other words, the UE 402 may alternate between a sleep cycle where one or more components are powered down, and a wake cycle where data transfers may occur. In some aspects, the DRX may provide significant power savings at the UE 402 since at least the reception component 412 can be turned off.

As described above, the UE 402 may be capable of advanced access (e.g., 5G NR access) . In order to acquire 5G service, the background search component 141 may perform one or more cell searches to detect a 5G NR cell of one of the second RAT base stations 408 (1) - (N) . However, repeatedly performing cell searches can significantly drain the battery 140. Accordingly, in order to balance power consumption and the eagerness of the UE 402 to connect to a 5G network via one of the second RAT base stations 408 (1) - (N) , the background search component 141 may set search parameters for the cell searches based at least in part on one or more attributes of the battery 140. For example, the background search component 141 may perform cell searches more frequently and for longer durations when the battery level of the battery 140 is above a first threshold. As another example, the background search component 141 may perform cell searches less frequently and for shorter durations when the battery level of the battery 140 is below a second threshold. In some other examples, there may be a plurality of different thresholds. For instance, the background search component 141 may perform a first plurality of searches with an interval period of 2 minutes and a duration period of 30 seconds based at least in part on the battery level being 50%or more, a second plurality of searches with an interval period of 4 minutes and a duration period of 20 seconds based at least in part on the battery level being between 20%and 50%, or a third plurality of searches with an interval period of 8 minutes and a duration period of 10 seconds based at least in part on the battery level being 20%or less.

In some aspects, the background search component 141 may store information identifying a battery attribute to use when determining one or more search parameters, and one or more thresholds to apply when determining the search parameters. For example, the background search component 141 may store information identifying three battery level ranges, and corresponding interval parameters and duration parameters to be applied to the cell searches when the current battery level of the battery 140 falls within one of the battery levels ranges. Further, the background search component 141 may determine a value of the battery attribute based on evaluating the battery 140. For example, the background search component 141 may determine the current battery level of the battery 140. In addition, the background search component 141 may compare the value to the one or more thresholds to determine search parameters. For example, the background search component 141 may determine which range the current battery level falls within. Additionally, the background search component 141 may perform a plurality of cell searches based on the search parameters. For example, the background search component 141 may perform a plurality of cell searches for a duration of the duration parameter corresponding to the determined range at intervals equal to the interval parameter corresponding to the determined range. Performing the plurality of cell searches in view of the battery attribute value may help the UE 402 acquire 5G service according to the battery power level of the UE 402.

FIG. 5 is a flowchart of a method 500 of wireless communication. The method may be performed by a UE (e.g., the UE 402; the UE 602; the processing system 714, which may include the memory 360 and which may be the entire UE 402 or a component of the UE 402, such as the background search component 141, the TX processor 368, the RX processor 356, and/or the controller/processor 359) .

At block 502, the method 500 may optionally include setting a cell search profile for the cell search in the second RAN, the cell search profile indicating one or more battery threshold values, an interval parameter, and a duration parameter. For example, the UE 402 may configure the cell search profile 142 via an application programming interface (API) . Further, in some aspects, for one or more battery attributes, the cell search profile 142 may include relationships between battery attribute thresholds and search parameters. For instance, the cell search profile 142 may map a set of search parameters to battery attribute values falling in between two battery attribute thresholds. In some aspects, a manufacturer of the UE 402 may configure the cell search profile. Accordingly, the UE 104, the RX processor 356, and/or the controller/processor 359 executing the background search component 141 may provide means for setting a cell search profile for the cell search in the second RAN.

At block 510, the method 500 may include determining a battery attribute value of the user equipment connected to a first radio access network (RAN) . For example, the attribute detection component 143 may determine an attribute value of the battery 140 of the UE 402 connected to the first RAT base station 404. Accordingly, the UE 104, the RX processor 356, and/or the controller/processor 359 executing the background search component 141 and/or the attribute detection component 143 may provide means for determining a battery attribute value of the user equipment connected to a first RAN.

At sub-block 512, the block 510 may optionally include determining a battery level of the UE 402. For example, the attribute detection component 143 may determine that the battery level of the battery 140 is 60%.

At sub-block 514, the block 510 may optionally include determining a battery health of the UE 402. For example, the attribute detection component 143 may determine that the maximum capacity of the battery 140 is 82%of its original battery capacity.

Some other examples of battery attributes includes battery performance, battery lifespan, temperature characteristics, charging characteristics, etc. For example, when battery performance is sub-optimal, the background search component 141 may perform cell searches less frequently and for shorter durations. As another example, the background search component 141 may perform cell searches more frequently and for longer durations when the battery 140 of the UE 402 is being charged.

At block 520, the method 500 may include determining, based on the battery attribute value, an interval period and a duration period for a second RAN cell search. For example, the configuration component 144 may determine an interval period and a duration period for a plurality of cell searches to be performed by the UE 402 to acquire service from one of the second RAT base stations 408 (1) - (N) . In some examples, the plurality of cells searches may be performed to acquire 5G service from the second RAT base stations 408 (1) - (N) . Accordingly, the UE 104, the RX processor 356, and/or the controller/processor 359 executing the background search component 141 and/or the configuration component 144 may provide means for determining, based on the battery attribute value, an interval period and a duration period for a second RAN cell search.

At sub-block 522, the block 520 may optionally include comparing the battery health to the one or more battery threshold values and determining, based on the comparing, the interval period and the duration period. For example, the configuration component 144 may be configured to set the interval and duration period to a first pair of values when the battery health is 80%and above, and a second pair of values when the battery health is below 80%. In some aspects, the configuration component 144 may set the interval period and duration period based on the battery level when the battery health is above 80%, and set the interval period and duration period as if the battery level is low when the battery health is below 80%. For instance, the configuration component 144 may determine that the interval period and duration period should be set to the third pair of values corresponding to a battery level above 50%given that the current battery health is above 80%.

At block 530, the method 500 may include performing, by the user equipment during a wake up cycle of a reduced power mode, a plurality of cell searches to connect to a cell in a second RAN, a second cell search of the plurality of cell searches performed for the duration period and succeeding a first cell search of the plurality of cell searches by the interval period. For example, the search component 145 may perform a first cell search for the duration period at a first point in time, and perform a second cell search for the duration period at second point time succeeding the first point in time by the interval period. In addition, the plurality of cells searches may be performed during a wake cycle of DRX by the UE 402. For example, the search component 145 may align the beginning of a first cell search with the beginning of a DRX wake cycle, and ensure that the first cell search or a subsequently performed second cell search ends before the end of the DRX wake cycle. As such, the plurality of cell searches may be performed in the background as not to disrupt battery conservation techniques performed in a low power mode. Further, if the interval period would lead to a cell search being performed during a sleep cycle, the search component 145 may delay the cell search until the next wake cycle. Accordingly, the UE 104, the RX processor 356, and/or the controller/processor 359 executing the background search component 141 and/or the search component 145 may provide means for performing, by the user equipment during a wake up cycle of a reduced power mode, a plurality of cell searches to connect to a cell in a second RAN, a second cell search of the plurality of cell searches performed for the duration period and succeeding a first cell search of the plurality of cell searches by the interval period.

At sub-block 532, the block 530 may optionally include tuning to a frequency band during the first cell search and monitoring the frequency band for a PSS, a SSS, and/or PBCH. For example, the search component 145 may implement a first 5G NR cell search over a first frequency band to detect and decode a ST 410. Further, if the search is unsuccessful, the search component 145 may implement a second 5G NR cell search over a second frequency band to detect and decode a ST 410. The first 5G NR cell search and the second 5G NR cells search may be individually performed for the duration period, and the second 5G NR cell search may be performed after the first 5G NR cell search by the interval period. In some aspects, one or more timers may be used to calculate the duration period and/or interval period.

Further, in some aspects, the search component 145 may manage an identifier (e.g., a last frequency search identifier) of the frequency band searched during the last completed cell search. Further, the search component 145 may determine the next frequency band to search based on the identifier. For example, the search component 145 may apply an increment or decrement to the identified frequency band to determine the next frequency band to search. In some aspects, the increment or decrement may be a pre-defined channel raster.

Although aspects of the present disclosure make reference to a first cell search and a second cell search, the UE 402 may perform cell searches until wireless service is acquired from the second RAT base station 408 in accordance with the duration period and the interval period.

In some aspects, the plurality of cell searches may be performed across different wake cycles of DRX. For example, the first cell search and the second cell search may be performed during a first wake cycle, and a third cell search and fourth cell search may be performed during a subsequent wake cycle. Although aspects make reference to a first wake cycle and a second wake cycle, the UE 402 may alternate between wake cycles and sleep cycles while in a low power mode.

Additionally, the UE 402 may repeat the method 500. For example, in response to a trigger event (e.g., passage of time, loss of 5G service, etc. ) , the UE 402 may update the attribute value and update the search parameters based upon the updated attribute value. Further, the search component 145 may subsequently perform the plurality of searches based upon the updated search parameters. For example, the attribute detection component 143 may determine a second battery attribute value of the UE 402, and the configuration component may determine, based on the second battery attribute value, a second interval period and a second duration period for the cell search in the second RAN. Further, the search component 145 may perform a fourth cell search for the second duration period and succeeding a third cell search by the second interval period.

FIG. 6 is a conceptual data flow diagram 600 illustrating the data flow between different means/components in an example UE 602, which may be an example of the UE 104 and include the background search component 141. The apparatus may be a UE 103 or the UE 402.

The battery 140 may provide power to the UE 602. The cell search profile 142 may identify one or more battery attributes that may be used to determine search parameters for the cell searches performed by the search component 145. Further, the cell search profile 142 may include one or more thresholds for the battery attributes that may be used to determine the search parameters. In some aspects, the cell search profile 142 may be defined and/or configured at least in part by a manufacturer of the UE 602. Further, the cell search profile 142 may be defined and/or configured via an API. Alternatively, in some other aspects, the cell search profile 142 or the API may be inaccessible to a manufacturer of the UE 602.

The cell search profile 142 may provide the identify the one or more battery attributes to the attribute detection component 143. Further, the attribute detection component 143 may determine a value of the identified battery attribute, and provide the determined value to the configuration component 144. For example, the identified battery attribute may be the battery level of the battery 140, and the attribute detection component 143 may determine the battery level of the battery 140. Additionally, or alternatively, the one or more battery attributes may include battery health, and the attribute detection component 143 may determine the battery health of the battery 140 by comparing the current battery capacity of the battery 140 to its original battery capacity.

The configuration component 144 may receive the one or more thresholds from the cell search profile 142, and compare the determined value to the one or more thresholds to determine search parameters (e.g., an interval period and a duration period) . As an example, the configuration component 144 may set the interval period to 4 minutes and the duration period to 20 seconds based at least in part on the battery level being between 20%and 50%. As another example, the configuration component 144 may set the interval period to 8 minutes and the duration period to 10 seconds based at least in part on the battery capacity being less than 80%. Once the configuration component 144 determines the search parameters, it may send the search parameters to the search component 145.

In response to receipt of the search parameters from the configuration component 144, the search component 145 may perform one or more of cell searches based on the search parameters. In some aspects, for an individual cell search, the search component 145 may send tuning parameters to the reception component 412 that tune the reception component 412 to a particular frequency band. Further, the reception component 412 may receive Sync Info (e.g., a ST 410) from a second RAT base station at the frequency band, and provide the sync info to the search component 145 for completion of the search and cell selection. For example, the search component 145 may perform a cell search procedure to acquire time and frequency synchronization via the ST 410, and decode an identifier of the cell obtained using the ST 410. Further, the ST 410 may be an SSB transmission including a PSS, a SSS, and a PBCH.

The mode management component 146 may manage DRX by the UE 402. For instance, the mode management component 146 may control entering and exiting the wake and sleep modes of DRX. Further, the mode management component 146 may facilitate powering down of the other components of the UE 402 in the sleep mode and powering up the other components of the UE 402 in the wake mode. For instance, the mode management component 146 may power down the reception component 412 in the sleep mode.

The apparatus may include additional components that perform each of the blocks of the algorithm in the aforementioned flowchart of FIG. 5. As such, each block in the aforementioned flowcharts of FIG. 5 may be performed by a component and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium (e.g., a non-transitory computer-readable medium) for implementation by a processor, or some combination thereof.

FIG. 7 is a diagram 700 illustrating an example of a hardware implementation for an UE 602 employing a processing system 714. The processing system 714 may be implemented with a bus architecture, represented generally by the bus 724. The bus 724 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 714 and the overall design constraints. The bus 724 links together various circuits including one or more processors and/or hardware components, represented by the processor 704, the cell search profile 142, the attribute detection component 143, the configuration component 144, the search component 145, and the mode management component 146, and the computer-readable medium /memory 706. The bus 724 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system 714 may be coupled with a transceiver 710. The transceiver 710 is coupled with one or more antennas 720. The transceiver 710 provides a means for communicating with various other apparatus over a transmission medium. The transceiver 710 receives a signal from the one or more antennas 720, extracts information from the received signal, and provides the extracted information to the processing system 714, specifically the reception component 412. In addition, the transceiver 710 receives information from the processing system 714, specifically the transmission component 414, and based on the received information, generates a signal to be applied to the one or more antennas 720. The processing system 714 includes a processor 704 coupled with a computer-readable medium /memory 706. The processor 704 is responsible for general processing, including the execution of software stored on the computer-readable medium /memory 706. The software, when executed by the processor 704, causes the processing system 714 to perform the various functions described supra for any particular apparatus. The computer-readable medium /memory 706 may also be used for storing data that is manipulated by the processor 704 when executing software. The processing system 714 further includes at least one of the attribute detection component 143, the configuration component 144, the search component 145, and the mode management component 146. The components may be software components running in the processor 704, resident/stored in the computer readable medium /memory 706, one or more hardware components coupled with the processor 704, or some combination thereof. The processing system 714 may be a component of the UE 350 and may include the memory 360 and/or at least one of the TX processor 368, the RX processor 356, and the controller/processor 359. Alternatively, the processing system 714 may be the entire UE (e.g., see 350 of FIG. 3) .

In one configuration, the UE 602 for wireless communication includes means for determining a battery attribute value of the user equipment connected to a first radio access network (RAN) , determining, based on the battery attribute value, an interval period and a duration period for a second RAN cell search; and performing, by the user equipment during a wake up cycle of a reduced power mode, a plurality of cell searches to connect to a cell in a second RAN, a second cell search of the plurality of cell searches performed for the duration period and succeeding a first cell search of the plurality of cell searches by the interval period. The aforementioned means may be one or more of the aforementioned components of the UE 602 and/or the processing system 714 of the UE 602 configured to perform the functions recited by the aforementioned means. As described supra, the processing system 714 may include the TX Processor 368, the RX Processor 356, and the controller/processor 359. As such, in one configuration, the aforementioned means may be the TX Processor 368, the RX Processor 356, and the controller/processor 359 configured to perform the functions recited by the aforementioned means.

In view of the foregoing, enabling battery-level based background search improves user experience by balancing power consumption by a UE and eagerness of the UE to connect to a more preferable network. In particular, modifying the parameters of a background cell search in view of the battery attributes of the UE, ensures that operations to acquire more favorable service do not drain the battery power of the UE.

It is understood that the specific order or hierarchy of blocks in the processes /flowcharts disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes /flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module, ” “mechanism, ” “element, ” “device, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ”

Claims

A method of wireless communication at a user equipment, comprising:

determining a battery attribute value of the user equipment connected to a first radio access network (RAN) ;

determining, based on the battery attribute value, an interval period and a duration period for a cell search in a second RAN; and

performing, by the user equipment during a wake up cycle of a reduced power mode, a plurality of cell searches to connect to a cell in the second RAN, a second cell search of the plurality of cell searches performed for the duration period and succeeding a first cell search of the plurality of cell searches by the interval period.
The method of claim 1, wherein determining the battery attribute value comprises determining a battery level of the user equipment.
The method of claim 2, wherein determining the interval period and the duration period comprises:

comparing the battery level to one or more battery threshold values; and

determining, based on the comparing, the interval period and the duration period.
The method of claim 1, further comprising: setting a cell search profile for the cell search in the second RAN, the cell search profile indicating one or more battery threshold values, an interval parameter, and a duration parameter.
The method of claim 4, wherein the battery attribute value is a battery level of the user equipment, and determining the interval period and the duration period comprises:

comparing the battery level to the one or more battery threshold values; and

setting, based on the comparing, the interval period to the interval parameter and the duration period to the duration parameter.
The method of claim 1, wherein the battery attribute value is a first battery attribute value , the interval period is a first interval period, the duration period is a first duration period, the plurality of cell searches is a first plurality of cell searches, and further comprising:

determining a second battery attribute value of the user equipment;

determining, based on the second battery attribute value, a second interval period and a second duration period for the cell search in the second RAN; and

performing, by the user equipment during the reduced power mode, a fourth cell search of a second plurality of cell searches performed for the second duration period and succeeding a third cell search of the second plurality of cell searches by the second interval period.
The method of claim 1, wherein the first RAN is a 2G, 3G, or 4G network, and performing the plurality of cell searches comprises performing the plurality of cell searches in a discontinuous reception mode.
The method of claim 1, wherein the second RAN is a 5G network, and performing the plurality of cell searches comprises:

tuning to a frequency band during the first cell search; and

monitoring the frequency band for a primary synchronization signal (PSS) , secondary synchronization signal (SSS) , and physical broadcast channel (PBCH) .
The method of claim 1, wherein the wake up cycle is a first wake up cycle, and performing the plurality of cell searches comprises:

searching, during the first wake up cycle, a first frequency band in the first cell search;

storing a last frequency search identifier indicating completion of the first cell search; and

searching, during a second wake up cycle, a second frequency band in the second cell search based upon the last frequency search identifier.
The method of claim 1, wherein the battery attribute value is a maximum capacity of a battery of the user equipment, and wherein determining the interval period and the duration period comprises comparing the maximum capacity of the battery to one or more battery threshold values.
The method of claim 4, wherein at least one of the one or more battery threshold values, the interval parameter, or the duration parameter are configured by a manufacturer of the user equipment via an application programming interface.
A user equipment for wireless communication, comprising:

a memory storing computer-executable instructions; and

at least one processor coupled with the memory and configured to execute the computer-executable instructions to perform the method of any of claims 1-11.
A user equipment for wireless communication, comprising means for performing the method of any of claims 1-11.
A non-transitory computer-readable medium storing computer executable code, the code when executed by a processor causes the processor to perform the method of any of claims 1-11.