WO2021138825A1

WO2021138825A1 - Cell reselection according to dual connectivity support

Info

Publication number: WO2021138825A1
Application number: PCT/CN2020/070809
Authority: WO
Inventors: Shanshan Wang; Arvind Vardarajan Santhanam; Reza Shahidi; Jun Deng; Kuo-Chun Lee; Jiming Guo; Xiaochen Chen; Zengyu Hao
Original assignee: Qualcomm Incorporated
Priority date: 2020-01-08
Filing date: 2020-01-08
Publication date: 2021-07-15

Abstract

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine whether a frequency band associated with a cell, of a plurality of cells, supports dual connectivity with a first radio access technology (RAT) and a second RAT. The UE may adjust at least one of a reselection priority or a cell reselection signal quality metric associated with the cell based at least in part on whether the frequency band supports the dual connectivity. The UE may select from the plurality of cells based at least in part on adjusting the at least one of the reselection priority or the cell reselection signal quality metric associated with the cell. Numerous other aspects are provided.

Description

CELL RESELECTION ACCORDING TO DUAL CONNECTIVITY SUPPORT

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for cell reselection according to dual connectivity support.

BACKGROUND

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 (e.g., bandwidth, transmit power, and/or the like) . Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, single-carrier frequency-division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE) . LTE/LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP) .

A wireless communication network may include a number of base stations (BSs) that can support communication for a number of user equipment (UEs) . A user equipment (UE) may communicate with a base station (BS) via the downlink and uplink. The downlink (or forward link) refers to the communication link from the BS to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the BS. As will be described in more detail herein, a BS may be referred to as a Node B, a gNB, an access point (AP) , a radio head, a transmit receive point (TRP) , a New Radio (NR) BS, a 5G Node B, and/or the like.

The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user equipment to communicate on a municipal, national, regional, and even global level. New Radio (NR) , which may also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP) . NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) (CP-OFDM) on the downlink (DL) , using CP-OFDM and/or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM) ) on the uplink (UL) , as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE and NR technologies. Preferably, these improvements should be applicable to other multiple access technologies and the telecommunication standards that employ these technologies.

SUMMARY

In some aspects, a method of wireless communication, performed by a user equipment (UE) , may include determining whether a frequency band associated with a cell, of a plurality of cells, supports dual connectivity with a first radio access technology (RAT) and a second RAT; adjusting at least one of a reselection priority or a cell reselection signal quality metric associated with the cell based at least in part on whether the frequency band supports the dual connectivity; and selecting from the plurality of cells based at least in part on adjusting the at least one of the reselection priority or the cell reselection signal quality metric associated with the cell.

In some aspects, a UE for wireless communication may include memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to determine whether a frequency band associated with a cell, of a plurality of cells, supports dual connectivity with a first RAT and a second RAT; adjust at least one of a reselection priority or a cell reselection signal quality metric associated with the cell based at least in part on whether the frequency band supports the dual connectivity; and select from the plurality of cells based at least in part on adjusting the at least one of the reselection priority or the cell reselection signal quality metric associated with the cell.

In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a UE, may cause the one or more processors to: determine whether a frequency band associated with a cell, of a plurality of cells, supports dual connectivity with a first RAT and a second RAT; adjust at least one of a reselection priority or a cell reselection signal quality metric associated with the cell based at least in part on whether the frequency band supports the dual connectivity; and select from the plurality of cells based at least in part on adjusting the at least one of the reselection priority or the cell reselection signal quality metric associated with the cell.

In some aspects, an apparatus for wireless communication may include means for determining whether a frequency band associated with a cell, of a plurality of cells, supports dual connectivity with a first RAT and a second RAT; means for adjusting at least one of a reselection priority or a cell reselection signal quality metric associated with the cell based at least in part on whether the frequency band supports the dual connectivity; and means for selecting from the plurality of cells based at least in part on adjusting the at least one of the reselection priority or the cell reselection signal quality metric associated with the cell.

Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and/or processing system as substantially described herein with reference to and as illustrated by the accompanying drawings and specification.

The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. Characteristics of the concepts disclosed herein, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purposes of illustration and description, and not as a definition of the limits of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects. The same reference numbers in different drawings may identify the same or similar elements.

Fig. 1 is a block diagram conceptually illustrating an example of a wireless communication network, in accordance with various aspects of the present disclosure.

Fig. 2 is a block diagram conceptually illustrating an example of a base station in communication with a UE in a wireless communication network, in accordance with various aspects of the present disclosure.

Fig. 3 is a diagram illustrating an example of cell selection according to dual connectivity support, in accordance with various aspects of the present disclosure.

Fig. 4 is a diagram illustrating an example process performed, for example, by a UE, in accordance with various aspects of the present disclosure.

DETAILED DESCRIPTION

Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

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

It should be noted that while aspects may be described herein using terminology commonly associated with 3G and/or 4G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as 5G and later, including NR technologies.

Fig. 1 is a diagram illustrating a wireless network 100 in which aspects of the present disclosure may be practiced. The wireless network 100 may be an LTE network or some other wireless network, such as a 5G or NR network. The wireless network 100 may include a number of BSs 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities. A BS is an entity that communicates with user equipment (UEs) and may also be referred to as a base station, a NR BS, a Node B, a gNB, a 5G node B (NB) , an access point, a transmit receive point (TRP) , and/or the like. Each BS may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to a coverage area of a BS and/or a BS subsystem serving this coverage area, depending on the context in which the term is used.

A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having association with the femto cell (e.g., UEs in a closed subscriber group (CSG) ) . A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in Fig. 1, a BS 110a may be a macro BS for a macro cell 102a, a BS 110b may be a pico BS for a pico cell 102b, and a BS 110c may be a femto BS for a femto cell 102c. A BS may support one or multiple (e.g., three) cells. The terms “eNB” , “base station” , “NR BS” , “gNB” , “TRP” , “AP” , “node B” , “5G NB” , and “cell” may be used interchangeably herein.

In some aspects, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS. In some aspects, the BSs may be interconnected to one another and/or to one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces such as a direct physical connection, a virtual network, and/or the like using any suitable transport network.

Wireless network 100 may also include relay stations. A relay station is an entity that can receive a transmission of data from an upstream station (e.g., a BS or a UE) and send a transmission of the data to a downstream station (e.g., a UE or a BS) . A relay station may also be a UE that can relay transmissions for other UEs. In the example shown in Fig. 1, a relay station 110d may communicate with macro BS 110a and a UE 120d in order to facilitate communication between BS 110a and UE 120d. A relay station may also be referred to as a relay BS, a relay base station, a relay, and/or the like.

Wireless network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, and/or the like. These different types of BSs may have different transmit power levels, different coverage areas, and different impacts on interference in wireless network 100. For example, macro BSs may have a high transmit power level (e.g., 5 to 40 Watts) whereas pico BSs, femto BSs, and relay BSs may have lower transmit power levels (e.g., 0.1 to 2 Watts) .

A network controller 130 may couple to a set of BSs and may provide coordination and control for these BSs. Network controller 130 may communicate with the BSs via a backhaul. The BSs may also communicate with one another, e.g., directly or indirectly via a wireless or wireline backhaul.

UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout wireless network 100, and each UE may be stationary or mobile. A UE may also be referred to as an access terminal, a terminal, a mobile station, a subscriber unit, a station, and/or the like. A UE may be a cellular phone (e.g., a smart phone) , a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, biometric sensors/devices, wearable devices (smart watches, smart clothing, smart glasses, smart wrist bands, smart jewelry (e.g., smart ring, smart bracelet) ) , an entertainment device (e.g., a music or video device, or a satellite radio) , a vehicular component or sensor, smart meters/sensors, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium.

Some UEs may be considered machine-type communication (MTC) or evolved or enhanced machine-type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, and/or the like, that may communicate with a base station, another device (e.g., remote device) , or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, and/or may be implemented as NB-IoT (narrowband internet of things) devices. Some UEs may be considered a Customer Premises Equipment (CPE) . UE 120 may be included inside a housing that houses components of UE 120, such as processor components, memory components, and/or the like.

In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, an air interface, and/or the like. A frequency may also be referred to as a carrier, a frequency channel, and/or the like. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly using one or more sidelink channels (e.g., without using a base station 110 as an intermediary to communicate with one another) . For example, the UEs 120 may communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, a vehicle-to-everything (V2X) protocol (e.g., which may include a vehicle-to-vehicle (V2V) protocol, a vehicle-to-infrastructure (V2I) protocol, and/or the like) , a mesh network, and/or the like. In this case, the UE 120 may perform scheduling operations, resource selection operations, and/or other operations described elsewhere herein as being performed by the base station 110.

As indicated above, Fig. 1 is provided as an example. Other examples may differ from what is described with regard to Fig. 1.

Fig. 2 shows a block diagram of a design 200 of base station 110 and UE 120, which may be one of the base stations and one of the UEs in Fig. 1. Base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 252a through 252r, where in general T ≥ 1 and R ≥ 1.

At base station 110, a transmit processor 220 may receive data from a data source 212 for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on channel quality indicators (CQIs) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS (s) selected for the UE, and provide data symbols for all UEs. Transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI) and/or the like) and control information (e.g., CQI requests, grants, upper layer signaling, and/or the like) and provide overhead symbols and control symbols. Transmit processor 220 may also generate reference symbols for reference signals (e.g., the cell-specific reference signal (CRS) ) and synchronization signals (e.g., the primary synchronization signal (PSS) and secondary synchronization signal (SSS) ) . A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and/or the reference symbols, if applicable, and may provide T output symbol streams to T modulators (MODs) 232a through 232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM and/or the like) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 234t, respectively. According to various aspects described in more detail below, the synchronization signals can be generated with location encoding to convey additional information.

At UE 120, antennas 252a through 252r may receive the downlink signals from base station 110 and/or other base stations 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 received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM and/or the like) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller/processor 280. A channel processor may determine reference signal received power (RSRP) , received signal strength indicator (RSSI) , reference signal received quality (RSRQ) , channel quality indicator (CQI) , and/or the like. In some aspects, one or more components of UE 120 may be included in a housing.

On the uplink, at UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information (e.g., for reports comprising RSRP, RSSI, RSRQ, CQI, and/or the like) from controller/processor 280. Transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, and/or the like) , and transmitted to base station 110. At base station 110, the uplink signals from UE 120 and other UEs may be received by antennas 234, processed by demodulators 232, detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by UE 120. Receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to controller/processor 240. Base station 110 may include communication unit 244 and communicate to network controller 130 via communication unit 244. Network controller 130 may include communication unit 294, controller/processor 290, and memory 292.

Controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component (s) of Fig. 2 may perform one or more techniques associated with cell selection according to dual connectivity support, as described in more detail elsewhere herein. For example, controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component (s) of Fig. 2 may perform or direct operations of, for example, process 400 of Fig. 4, and/or other processes as described herein.

Memories

242 and 282 may store data and program codes for base station 110 and UE 120, respectively. In some aspects, memory 242 and/or memory 282 may comprise a non-transitory computer-readable medium storing one or more instructions for wireless communication. For example, the one or more instructions, when executed by one or more processors of the base station 110 and/or the UE 120, may perform or direct operations of, for example, process 400 of Fig. 4, and/or other processes as described herein. A scheduler 246 may schedule UEs for data transmission on the downlink and/or uplink.

In some aspects, UE 120 may include means for determining whether a frequency band associated with a cell, of a plurality of cells, supports dual connectivity with a first RAT and a second RAT, means for adjusting at least one of a reselection priority or a cell reselection signal quality metric associated with the cell based at least in part on whether the frequency band supports the dual connectivity, means for selecting from the plurality of cells based at least in part on adjusting the at least one of the reselection priority or the cell reselection signal quality metric associated with the cell, and/or the like. In some aspects, such means may include one or more components of UE 120 described in connection with Fig. 2, such as controller/processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, and/or the like.

As indicated above, Fig. 2 is provided as an example. Other examples may differ from what is described with regard to Fig. 2.

Dual connectivity provides communication with regard to two or more RATs. One dual connectivity configuration is E-UTRAN-NR dual connectivity (EN-DC) between an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access network (E-UTRAN) , such as 4G/LTE, and an NR network, such as 5G/NR. For a UE performing EN-DC, data may be received on both a 4G/LTE connection and a 5G/NR leg (e.g., on a secondary cell group split bearer) , although other configurations are possible.

In some cases, a UE may be camped on an LTE frequency that is associated with a frequency band that does not support EN-DC. In such cases, despite 5G capability, the UE may not display an icon that indicates 5G coverage, which may be confusing to a user. In addition, without EN-DC, the UE may communicate at a lower throughput and/or a lower data rate. Moreover, when camped on an LTE frequency band that does not support EN-DC, the UE must first be handed over to a frequency band that supports EN-DC in order to initiate EN-DC, thereby delaying communications of the UE in EN-DC.

Some techniques and apparatuses described herein improve a likelihood that a UE will select a cell, during a cell reselection procedure, that supports EN-DC. For example, based at least in part on a determination that a cell is not likely to support EN-DC, the UE may adjust at least one of a reselection priority or a cell reselection signal quality metric associated with the cell. In this way, the UE may bias the cell reselection procedure towards selecting a cell that is likely to support EN-DC.

Fig. 3 is a diagram illustrating an example 300 of cell reselection according to dual connectivity support, in accordance with various aspects of the present disclosure. As shown in Fig. 3, example 300 may illustrate an example cell reselection procedure performed by a UE 120. The UE 120 may perform the cell reselection procedure to determine a cell, of a plurality of cells, on which the UE 120 is to camp. In some aspects, the plurality of cells may be included in the same wireless network (e.g., wireless network 100 and/or another wireless network) , may be included in a different wireless network, and/or the like. In some aspects, the plurality of cells may be implemented by the same BS (e.g., BS 110) and/or may be implemented by different BSs.

In some aspects, as described below, the cell reselection procedure may be biased such that the UE 120 is more likely to select a cell (e.g., a primary cell) that supports multi-RAT dual connectivity with a first RAT and a second RAT. In some aspects, the first RAT may be an LTE RAT and the second RAT may be an NR RAT. That is, the dual connectivity may be EN-DC. Although example 300 is described in terms of EN-DC, example 300 may also apply to another multi-RAT dual connectivity mode with a first RAT other than LTE and/or a second RAT other than NR. For example, in some aspects the first RAT and the second RAT may both be an NR RAT (e.g., NR dual connectivity (NR-DC) ) , the first RAT may be an NR RAT and the second RAT may be an LTE RAT (e.g., NR-E-UTRA dual connectivity (NE-DC) ) , or the like. In some aspects, the dual connectivity may be a next generation (NG) radio access network (RAN) E-UTRA-NR dual connectivity (NGEN-DC) .

As shown by reference number 305, the UE 120 may be camped on, or may reselect to, the serving cell. For example, the UE 120 may be camped on the serving cell, or may reselect to the serving cell, while in an idle mode. The serving cell may be associated with a reselection priority based at least in part on an operating frequency band of the serving cell. In some aspects, the frequency band of the serving cell may be associated with the first RAT. For example, the frequency band may be an LTE frequency band.

The serving cell may be one of a plurality of cells that may be selected by the UE 120 as part of a cell reselection procedure. Accordingly, while camped on the serving cell, the UE 120 may identify a remainder of the plurality of cells. For example, the UE 120 may receive from the serving cell a system information block (SIB) (e.g., a SIB type-5 (SIB5) or a SIB type-4 (SIB4) ) that includes a configuration for one or more neighboring cells to the serving cell. Additionally, or alternatively, the UE 120 may perform a neighboring cell discovery procedure to identify one or more neighboring cells to the serving cell.

The neighboring cells may be inter-frequency neighboring cells or intra-frequency neighboring cells, and may be associated with respective reselection priorities (e.g., according to the configuration) based at least in part on respective operating frequency bands of the neighboring cells. In some aspects, the respective frequency bands of the neighboring cells may also be associated with the first RAT. For example, the frequency bands may be LTE frequency bands.

As shown by reference number 310, the UE 120 may determine whether a timer is expired (i.e., the timer is not running) in order to determine whether to perform a reselection biasing procedure, as described below, for the plurality of cells. As shown by reference number 315, if the timer is expired (and is not to be re-initiated) , the UE 120 may determine that the UE 120 is not to perform the reselection biasing procedure for the plurality of cells (e.g., the UE 120 is to perform a cell reselection procedure without biasing one or more cells) . In some aspects, the UE 120 may initiate the timer based at least in part on a determination that the UE 120 is camped on a cell for which dual connectivity (e.g., EN-DC) is indicated by system information and/or a dual connectivity cell list (as described below) . At an expiration of the timer, the UE 120 may re-initiate the timer if the UE 120 is camped on another cell for which dual connectivity is indicated by system information and/or a dual connectivity cell list.

In some aspects, a duration of the timer may be based at least in part on whether the UE 120 is stationary. For example, if the UE 120 is stationary (e.g., according to an inertial sensor of the UE 120) the timer may have a greater duration than if the UE 120 is not stationary. Additionally, or alternatively, a duration of the timer may be based at least in part on a degree to which the UE 120 is moving. For example, if an amount of movement of the UE 120 satisfies (e.g., is less than) a threshold value, if the UE 120 is within coverage of the same wireless network for a threshold time period (e.g., according to a basic service set identifier (BSSID) ) , and/or if a quantity of serving cells reselected by the UE 120 satisfies (e.g., is less than) a threshold value, the timer may have a greater duration than if any of the aforementioned conditions are not satisfied. Additionally, or alternatively, a duration of the timer may be different based at least in part on a location of the UE 120. For example, the timer may have a first duration if the UE 120 is located in a first geo-polygon and a second duration if the UE 120 is located in a second geo-polygon. In some aspects, a particular duration that is to be used for a particular geo-polygon may be based at least in part on historical data from the UE 120 and/or one or more other UEs. In some aspects, a duration of the timer may be particular to a cell on which the UE 120 is camped, and the duration may be based at least in part on historical data from the UE 120 and/or one or more other UEs.

As shown by reference number 320, if the timer is not expired, the UE 120 may determine whether a frequency band associated with the serving cell (on which the UE 120 is camped) is capable of dual connectivity (e.g., EN-DC) with the first RAT (e.g., LTE) and the second RAT (e.g., NR) . In some aspects, the UE 120 may identify the frequency band associated with the serving cell based at least in part on a mapping of an operating frequency of the serving cell to the frequency band (e.g., according to an E-UTRA Absolute Radio Frequency Channel Number (EARFCN) associated with the operating frequency) . In some aspects, the UE 120 may determine that the frequency band is capable of the dual connectivity based at least in part on a determination that the UE 120, and a network associated with the serving cell, are configured to use the frequency band for the dual connectivity. Accordingly, the UE 120 may determine that the serving cell supports the dual connectivity (e.g., is in NR coverage) based at least in part on a determination that the frequency band associated with the serving cell is capable of the dual connectivity.

As shown by reference number 325, based at least in part on a determination that the serving cell is not capable of the dual connectivity, the UE 120 may determine whether dual connectivity is indicated for the serving cell. In some aspects, the UE 120 may determine that dual connectivity is indicated for the serving cell based at least in part on system information. For example, the UE 120 may receive, from the serving cell, a SIB type-2 (SIB2) having an upper layer indication (ULI) that indicates whether the serving cell is associated with dual connectivity coverage (e.g., indicates whether the serving cell is associated with NR coverage) . In some aspects, the UE 120 may receive the SIB2 having the ULI in a case when the frequency band associated with the serving cell is not capable of the dual connectivity.

Additionally, or alternatively, the UE 120 may determine that dual connectivity is indicated for the serving cell based at least in part on a dual connectivity cell list (e.g., a database) . The dual connectivity cell list may be a list of cells (e.g., cell identifiers, such as cell global identifiers (CGIs) ) for which system information indicating dual connectivity was not received, but that the UE 120, or another UE, has determined are likely to support dual connectivity (e.g., the cells have a “fingerprint” of dual connectivity) . In some aspects, the dual connectivity cell list may be based at least in part on observation data. The observation data may include one or more observations (e.g., by the UE 120 or another UE, that is, the observation data may be crowdsourced and provided to the UE 120) of a past operation of a cell that indicates a likelihood of dual connectivity support. For example, the observation data may include an observation that the cell was previously configured with an LTE to NR (L2NR) neighboring cell, an observation that the cell previously established dual connectivity (e.g., previously added an NR cell as a primary secondary cell) , and/or the like.

Accordingly, the UE 120 may determine that the serving cell supports the dual connectivity (e.g., is in NR coverage) based at least in part on a determination that dual connectivity is indicated for the serving cell (e.g., according to system information or the dual connectivity cell list) .

As shown by reference number 330, the UE 120 may determine that the UE 120 is not to perform a reselection biasing procedure, as described below, for the serving cell and/or one or more intra-frequency neighboring cells (e.g., the UE 120 is to perform a cell reselection procedure without biasing one or more cells) . For example, the UE 120 may determine that the UE 120 is not to perform the reselection biasing procedure based at least in part on a determination that the serving cell supports the dual connectivity. That is, the frequency band associated with the serving cell is capable of the dual connectivity and/or dual connectivity is indicated for the serving cell, as described above.

As shown by reference number 335, if the timer is not expired, the UE 120 may determine whether frequency bands associated with one or more inter-frequency neighboring cells (and/or one or more intra-frequency neighboring cells, for example, when biasing of intra-frequency neighboring cells is not according to biasing of the serving cell) are capable of dual connectivity (e.g., EN-DC) with the first RAT (e.g., LTE) and the second RAT (e.g., NR) . In some aspects, the UE 120 may identify the frequency bands associated with the one or more inter-frequency (and/or intra-frequency) neighboring cells based at least in part on a mapping of operating frequencies of the inter-frequency (and/or intra-frequency) neighboring cell to frequency bands, as described above. In some aspects, the UE 120 may determine that a frequency band is capable of the dual connectivity based at least in part on a determination that the UE 120, and a network associated with an inter-frequency (and/or intra-frequency) neighboring cell, are configured to use the frequency band for dual connectivity, as described above. Accordingly, the UE 120 may determine that an inter-frequency (and/or intra-frequency) neighboring cell supports the dual connectivity (e.g., is in NR coverage) based at least in part on a determination that a frequency band associated with the inter-frequency (and/or intra-frequency) neighboring cell is capable of the dual connectivity.

As shown by reference number 340, the UE 120 may determine that the UE 120 is not to perform a reselection biasing procedure, as described below, for inter-frequency (and/or intra-frequency) neighboring cells that support the dual connectivity (e.g., the UE 120 is to perform a cell reselection procedure without biasing one or more cells) . For example, the UE 120 may determine that the UE 120 is not to perform the reselection biasing procedure for an inter-frequency (and/or intra-frequency) neighboring cell based at least in part on a determination that a frequency band associated with the inter-frequency (and/or intra-frequency) neighboring cell is capable of the dual connectivity, as described above.

As shown by reference number 345, the UE 120 may perform a reselection biasing procedure for one or more cells. For example, the UE 120 may determine that a cell does not support dual connectivity (e.g., EN-DC) , and thereby determine that the UE 120 is to perform the reselection biasing procedure for the cell. According to the reselection biasing procedure, the UE 120 may adjust a reselection priority and/or a cell reselection signal quality metric for a cell.

For example, the UE 120 may adjust respective reselection priorities and/or respective cell reselection signal quality metrics for the serving cell and/or one or more intra-frequency neighboring cells based at least in part on a determination that the serving cell does not support the dual connectivity (e.g., the frequency band associated with the serving cell is not capable of the dual connectivity and dual connectivity is not indicated for the serving cell) . As another example, the UE 120 may adjust respective reselection priorities and/or cell reselection signal quality metrics for the serving cell and/or one or more intra-frequency neighboring cells based at least in part on a determination that the frequency band associated with the serving cell is not capable of the dual connectivity but that dual connectivity is indicated for the serving cell (e.g., in a SIB2 ULI) . In such cases, the UE 120 may use a lesser adjustment relative to an adjustment that is used when the UE determines that the serving cell does not support the dual connectivity. As a further example, the UE 120 may adjust respective reselection priorities and/or respective cell reselection signal quality metrics for one or more inter-frequency (and/or intra-frequency) neighboring cells based at least in part on a determination that the one or more inter-frequency (and/or intra-frequency) neighboring cells do not support the dual connectivity (e.g., frequency bands associated with the one or more inter-frequency (and/or intra-frequency) neighboring cells are not capable of the dual connectivity) .

In some aspects, the UE 120 may adjust a reselection priority for a cell by decreasing the reselection priority. For example, the UE 120 may adjust the reselection priority to a value corresponding to a lowest reselection priority, among the plurality of cells, that is associated with a frequency of the first RAT (e.g., an LTE frequency) . As another example, the UE 120 may adjust the reselection priority to a value that is less than a lowest reselection priority (e.g., a lowest reselection priority associated with an LTE frequency) among the plurality of cells. In this case, the value may be a sub-priority value that is defined or configured to be less than a lowest reselection priority that may be configured for an LTE frequency (and greater than a highest reselection priority that may be configured for a frequency of another RAT other than the first RAT or the second RAT, such as a wideband CDMA (WCDMA) RAT or a global system for mobile communications (GSM) RAT) . In this way, when selecting from the plurality of cells according to reselection priority, the UE 120 is less likely to select a cell (e.g., from among LTE cells) that does not support the dual connectivity (e.g., EN-DC) based at least in part on the adjustment to the cell’s reselection priority.

In some aspects, the UE 120 may adjust a cell reselection signal quality metric for a cell by decreasing the cell reselection signal quality metric according to an adjustment value (Q _delta, such as 10 decibels or another configurable value) . The cell reselection signal quality metric may be a cell selection criteria (S-criteria) value (e.g., a cell selection receive (Rx) level (Srxlev) value, a cell selection quality (Squal) value, and/or the like) , a cell ranking, or a signal quality measurement (e.g., a reference signal received power (RSRP) measurement or a reference signal received quality (RSRQ) measurement) of the cell. In some aspects, the cell reselection signal quality metric may be an S-criteria value (e.g., an Srxlev value and/or an Squal value) when inter-frequency neighboring cells have nonequal reselection priorities, or the cell reselection signal quality metric may be a signal quality measurement (e.g., RSRP and/or RSRQ) when inter-frequency neighboring cells have equal reselection priorities. An S-criteria value or a cell ranking may be determined using formulas that are reduced by an offset value (e.g., Qoffset _temp) . Accordingly, the UE 120 may decrease an S-criteria value or a cell ranking by setting the offset value to the adjustment value (otherwise, the offset value may be zero) . Similarly, the UE 120 may decrease a signal quality measurement by the adjustment value. In this way, when selecting from the plurality of cells according to one or more cell selection criteria (e.g., an S-criteria value, a ranking, or a signal quality measurement) , the UE 120 is less likely to select a cell that does not support the dual connectivity (e.g., EN-DC) based at least in part on the adjustment to one or more of the cell’s cell reselection signal quality metrics.

In some aspects, the UE 120 may determine that the UE 120 is to perform a reselection biasing procedure for a cell (e.g., the serving cell, one or more intra-frequency neighboring cells, and/or one or more inter-frequency neighboring cells) based at least in part on a determination that the cell supports the dual connectivity (e.g., EN-DC) . In this case, the UE 120 may adjust a reselection priority and/or a cell reselection signal quality metric for the cell by increasing the reselection priority and/or the cell reselection signal quality metric. In some aspects, the UE 120 may decrease a reselection priority and/or a cell reselection signal quality metric of a cell that is determined not to support the dual connectivity and increase a reselection priority and/or a cell reselection signal quality metric of a cell that is determined to support the dual connectivity.

After performing the reselection biasing procedure, the UE 120 may select a cell (e.g., according to a cell selection procedure) from the plurality of cells on which the UE 120 is to camp. For example, the UE 120 may determine to remain on the serving cell or may reselect to a neighboring cell. The UE 120 may select the cell based at least in part on the adjusted (or non-adjusted) reselection priorities and/or cell reselection signal quality metrics for the plurality of cells. In this way, the UE 120’s selection of the cell is biased toward reselecting a cell that supports dual connectivity (e.g., the cell is in NR coverage) . By selecting a cell that supports the dual connectivity, the UE 120 may increase a display time of a 5G icon on the UE 120, improve a throughput or a data rate of communications of the UE 120, and/or decrease a time that is needed for initiating the dual connectivity with a secondary cell of the second RAT (e.g., NR) .

In some aspects, the UE 120 may determine cells for which the reselection biasing procedure is to be performed, and perform the reselection biasing procedure for the determined cells, each time the UE 120 reselects to a new cell or otherwise changes cells. In this case, previous adjustments to reselection priorities and/or cell reselection signal quality metrics may not be carried over to a subsequent reselection biasing procedure. In some aspects, the UE 120 may perform a subsequent reselection biasing procedure for the determined cells based at least in part on a determination that the timer is running. In this case, and as described above, the UE 120 may re-initiate the timer after reselecting to the new cell if the timer is expired and dual connectivity is indicated for the new cell.

As indicated above, Fig. 3 is provided as an example. Other examples may differ from what is described with respect to Fig. 3.

Fig. 4 is a diagram illustrating an example process 400 performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process 400 is an example where the UE (e.g., UE 120, and/or the like) performs operations associated with cell reselection according to dual connectivity support.

As shown in Fig. 4, in some aspects, process 400 may include determining whether a frequency band associated with a cell, of a plurality of cells, supports dual connectivity with a first RAT and a second RAT (block 410) . For example, the UE (e.g., using controller/processor 280, and/or the like) may determine whether a frequency band associated with a cell, of a plurality of cells, supports dual connectivity with a first RAT and a second RAT, as described above.

As further shown in Fig. 4, in some aspects, process 400 may include adjusting at least one of a reselection priority or a cell reselection signal quality metric associated with the cell based at least in part on whether the frequency band supports the dual connectivity (block 420) . For example, the UE (e.g., using controller/processor 280, and/or the like) may adjust at least one of a reselection priority or a cell reselection signal quality metric associated with the cell based at least in part on whether the frequency band supports the dual connectivity, as described above.

As further shown in Fig. 4, in some aspects, process 400 may include selecting from the plurality of cells based at least in part on adjusting the at least one of the reselection priority or the cell reselection signal quality metric associated with the cell (block 430) . For example, the UE (e.g., using controller/processor 280, and/or the like) may select from the plurality of cells based at least in part on adjusting the at least one of the reselection priority or the cell reselection signal quality metric associated with the cell, as described above.

Process 400 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 first RAT is one of an LTE RAT or an NR RAT, and the second RAT is the other of the LTE RAT or the NR RAT. In a second aspect, alone or in combination with the first aspect, the dual connectivity is EN-DC.

In a third aspect, alone or in combination with one or more of the first and second aspects, the at least one of the reselection priority or the cell reselection signal quality metric is adjusted based at least in part on a determination that a timer is not expired. In a fourth aspect, alone or in combination with one or more of the first through third aspects, process 400 includes initiating the timer based at least in part on a determination that the timer is not running and that the UE is camped on a particular cell for which support for the dual connectivity is indicated by system information or a dual connectivity cell list.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the reselection priority is adjusted to a value that is less than or equal to a lowest reselection priority, among the plurality of cells, that is associated with a frequency band of the first RAT, and is greater than a highest reselection priority, among the plurality of cells, that is associated with a frequency band of another RAT. In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the cell reselection signal quality metric includes at least one of a cell selection criteria value, a ranking, or a signal quality measurement, and the cell reselection signal quality metric is adjusted according to an adjustment value.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the cell is a serving cell. In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, determining whether the frequency band supports the dual connectivity includes determining whether the frequency band is capable of the dual connectivity, and determining whether the dual connectivity is indicated for the serving cell by system information or a dual connectivity cell list. In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, the dual connectivity cell list includes the serving cell based at least in part on at least one of an observation that the serving cell was previously configured with a L2NR neighboring cell, or an observation that the serving cell previously established the dual connectivity. In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, process 400 includes adjusting at least one of a reselection priority or a cell reselection signal quality metric associated with one or more intra-frequency neighboring cells to the serving cell based at least in part on whether the frequency band supports the dual connectivity.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, the cell is an inter-frequency neighboring cell or an intra-frequency neighboring cell to a serving cell. In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, determining whether the frequency band supports the dual connectivity includes determining whether the frequency band is capable of the dual connectivity.

In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, process 400 includes identifying one or more neighboring cells included in the plurality of cells based at least in part on a configured list of neighboring cells or based at least in part on performing a neighboring cell discovery procedure.

Although Fig. 4 shows example blocks of process 400, in some aspects, process 400 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in Fig. 4. Additionally, or alternatively, two or more of the blocks of process 400 may be performed in parallel.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects.

As used herein, the term “component” is intended to be broadly construed as hardware, firmware, and/or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, and/or a combination of hardware and software.

As used herein, satisfying a threshold may, depending on the context, refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, and/or the like.

It will be apparent that systems and/or methods described herein may be implemented in different forms of hardware, firmware, and/or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and/or methods is not limiting of the aspects. Thus, the operation and behavior of the systems and/or methods were described herein without reference to specific software code-it being understood that software and hardware can be designed to implement the systems and/or methods based, at least in part, on the description herein.

Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various aspects includes each dependent claim in combination with every other claim in the claim set. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c) .

No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more. ” Furthermore, as used herein, the terms “set” and “group” are intended to include one or more items (e.g., related items, unrelated items, a combination of related and unrelated items, and/or the like) , and may be used interchangeably with “one or more. ” Where only one item is intended, the phrase “only one” or similar language is used. Also, as used herein, the terms “has, ” “have, ” “having, ” and/or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.

Claims

A method of wireless communication performed by a user equipment (UE) , comprising:

determining whether a frequency band associated with a cell, of a plurality of cells, supports dual connectivity with a first radio access technology (RAT) and a second RAT;

adjusting at least one of a reselection priority or a cell reselection signal quality metric associated with the cell based at least in part on whether the frequency band supports the dual connectivity; and

selecting from the plurality of cells based at least in part on adjusting the at least one of the reselection priority or the cell reselection signal quality metric associated with the cell.
The method of claim 1, wherein the first RAT is one of a Long Term Evolution (LTE) RAT or a New Radio (NR) RAT, and the second RAT is the other of the LTE RAT or the NR RAT.
The method of claim 1, wherein the dual connectivity is Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network-New Radio dual connectivity.
The method of claim 1, wherein the at least one of the reselection priority or the cell reselection signal quality metric is adjusted based at least in part on a determination that a timer is not expired.
The method of claim 4, further comprising:

initiating the timer based at least in part on a determination that the timer is not running and that the UE is camped on a particular cell for which support for the dual connectivity is indicated by system information or a dual connectivity cell list.
The method of claim 1, wherein the reselection priority is adjusted to a value that is less than or equal to a lowest reselection priority, among the plurality of cells, that is associated with a frequency band of the first RAT, and is greater than a highest reselection priority, among the plurality of cells, that is associated with a frequency band of another RAT.
The method of claim 1, wherein the cell reselection signal quality metric includes at least one of a cell selection criteria value, a ranking, or a signal quality measurement, and

wherein the cell reselection signal quality metric is adjusted according to an adjustment value.
The method of claim 1, wherein the cell is a serving cell.
The method of claim 8, wherein determining whether the frequency band supports the dual connectivity comprises:

determining whether the frequency band is capable of the dual connectivity; and

determining whether the dual connectivity is indicated for the serving cell by system information or a dual connectivity cell list.
The method of claim 9, wherein the dual connectivity cell list includes the serving cell based at least in part on at least one of:

an observation that the serving cell was previously configured with a Long Term Evolution to New Radio neighboring cell; or

an observation that the serving cell previously established the dual connectivity.
The method of claim 8, further comprising:

adjusting at least one of a reselection priority or a cell reselection signal quality metric associated with one or more intra-frequency neighboring cells to the serving cell based at least in part on whether the frequency band supports the dual connectivity.
The method of claim 1, wherein the cell is an inter-frequency neighboring cell or an intra-frequency neighboring cell to a serving cell.
The method of claim 12, wherein determining whether the frequency band supports the dual connectivity comprises:

determining whether the frequency band is capable of the dual connectivity.
The method of claim 1, further comprising:

identifying one or more neighboring cells included in the plurality of cells based at least in part on a configured list of neighboring cells or based at least in part on performing a neighboring cell discovery procedure.
A user equipment (UE) for wireless communication, comprising:

a memory; and

one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:

determine whether a frequency band associated with a cell, of a plurality of cells, supports dual connectivity with a first radio access technology (RAT) and a second RAT;

adjust at least one of a reselection priority or a cell reselection signal quality metric associated with the cell based at least in part on whether the frequency band supports the dual connectivity; and

select from the plurality of cells based at least in part on adjusting the at least one of the reselection priority or the cell reselection signal quality metric associated with the cell.
A non-transitory computer-readable medium storing one or more instructions for wireless communication, the one or more instructions comprising:

one or more instructions that, when executed by one or more processors of a user equipment (UE) , cause the one or more processors to:

determine whether a frequency band associated with a cell, of a plurality of cells, supports dual connectivity with a first radio access technology (RAT) and a second RAT;

adjust at least one of a reselection priority or a cell reselection signal quality metric associated with the cell based at least in part on whether the frequency band supports the dual connectivity; and

select from the plurality of cells based at least in part on adjusting the at least one of the reselection priority or the cell reselection signal quality metric associated with the cell.
An apparatus for wireless communication, comprising:

means for determining whether a frequency band associated with a cell, of a plurality of cells, supports dual connectivity with a first radio access technology (RAT) and a second RAT;

means for adjusting at least one of a reselection priority or a cell reselection signal quality metric associated with the cell based at least in part on whether the frequency band supports the dual connectivity; and

means for selecting from the plurality of cells based at least in part on adjusting the at least one of the reselection priority or the cell reselection signal quality metric associated with the cell.