WO2021223138A1

WO2021223138A1 - Improving cell selection over new radio

Info

Publication number: WO2021223138A1
Application number: PCT/CN2020/088900
Authority: WO
Inventors: Guojing LIU; Dongsheng Wang; Chaofeng HUI; Xiaomeng Lu
Original assignee: Qualcomm Incorporated
Priority date: 2020-05-07
Filing date: 2020-05-07
Publication date: 2021-11-11

Abstract

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may establish a connection with a first cell associated with a first radio access technology (RAT) while in a dual connectivity mode of operation. The UE may determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both. The UE may additionally determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based at least in part on the reference signal parameter, the received signal parameter, or both, satisfying the respective thresholds. The UE may establish a connection with a second cell associated with a second RAT based at least in part on determining that the cell selection criterion satisfies the cell selection criterion threshold.

Description

IMPROVING CELL SELECTION OVER NEW RADIO

FIELD OF TECHNOLOGY

The following relates generally to wireless communications and more specifically to improving cell selection over new radio.

BACKGROUND

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) . A wireless multiple-access communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support improving cell selection over new radio (NR) . In some wireless communications systems, a user equipment (UE) may support dual connectivity (DC) with NR and LTE. The UE may attach to a first cell, such as an anchor LTE cell, and may additionally establish a connection with a second cell, such as an NR cell. In cases where a third cell, such as a 3G cell, is also available, however, the UE may detach from the first cell, such as the LTE cell (thereby terminating dual connectivity with the NR cell) , and attach to the third cell, such as a 3G cell, when one or more criteria are met. This procedure is intended to improve data transfer at the UE when the performance of the first cell, such as the LTE cell, does not satisfy one or more given thresholds. However, this procedure may further result in frequent handovers between the first cell and the third cell, such as the LTE cell and the 3G cell, thereby preventing stable addition of a secondary cell group (SCG) and attachment to the second cell, such as the NR cell.

Generally, the described techniques provide for improved communications which may prevent frequent, unnecessary handovers between the first cell and the third cell, such as the LTE call and the 3G cell. In some aspects, a UE may establish a connection with a first cell associated with a first radio access technology (e.g., LTE cell) while in a dual connectivity mode of operation. The UE may compare a reference signal parameter associated with the first cell with a reference signal threshold, or compare a received signal parameter associated with the first cell with a received signal threshold, or both. In cases where one or both of the reference signal parameter or the received signal parameter satisfy the respective thresholds, the UE may compare a cell selection criterion associated with the first cell with a cell selection criterion threshold. In cases where the cell selection criterion satisfies the cell selection criterion threshold, the UE may establish a connection with another cell, such as a third cell, associated with a second radio access technology (e.g., 3G cell) . The techniques described herein may enable the UE to prevent frequent and unnecessary handovers between the first cell and the other cell, thereby improving communication stability and enabling stable SCG addition.

A method of wireless communication at a UE is described. The method may include establishing a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation, determining that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both, determining that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both, and establishing a connection with a second cell associated with a second radio access technology based on determining that the cell selection criterion satisfies the cell selection criterion threshold.

An apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to establish a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation, determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both, determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both, and establish a connection with a second cell associated with a second radio access technology based on determining that the cell selection criterion satisfies the cell selection criterion threshold.

Another apparatus for wireless communication at a UE is described. The apparatus may include means for establishing a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation, determining that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both, determining that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both, and establishing a connection with a second cell associated with a second radio access technology based on determining that the cell selection criterion satisfies the cell selection criterion threshold.

A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to establish a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation, determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both, determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both, and establish a connection with a second cell associated with a second radio access technology based on determining that the cell selection criterion satisfies the cell selection criterion threshold.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that a radio access technology timer may have expired, and transmitting, to a base station supporting the first cell, an attach request message for a second connection with the first cell based on determining that the radio access technology timer may have expired.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the base station supporting the first cell, an attach accept message, where the attach accept message may be received based on the attach request message, and establishing the second connection with the first cell associated with the first radio access technology based on the attach accept message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for initiating the radio access technology timer based on establishing the connection with the second cell associated with the second radio access technology, and determining that the radio access technology timer may have expired based on initiating the radio access technology timer and a timer duration.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for detaching from the first cell based on establishing the connection with the second cell.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from a base station supporting the first cell, a system information broadcast message including an indication of the cell selection criterion threshold, where determining that the cell selection criterion satisfies the cell selection criterion threshold may be based on receiving the system information broadcast message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from a base station supporting the first cell, at least one of a system information broadcast message, a radio resource control message, a synchronization signal block message, a configuration message, or downlink control information including an indication of at least one of the reference signal threshold or the received signal threshold, where determining that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter satisfies the received signal threshold, or both, may be based on receiving the at least one of the system information broadcast message, the radio resource control message, the synchronization signal block message, the configuration message, or the downlink control information including the indication.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that a second cell selection criterion associated with the second cell satisfies a second cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both, and where establishing the connection with the second cell may be based on the second cell selection criterion associated with the second cell satisfying the second cell selection criterion threshold.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second cell selection criterion associated with the second cell satisfies the second cell selection criterion threshold when the second cell selection criterion may be greater than the second cell selection criterion threshold.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the reference signal parameter does not satisfy the reference signal threshold, or that the received signal parameter does not satisfy the received signal threshold, or both, and maintaining the connection with the first cell based on determining that the reference signal parameter does not satisfy the reference signal threshold, or that the received signal parameter does not satisfy the received signal threshold, or both.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the cell selection criterion does not satisfy the cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both, and maintaining the connection with the first cell based on determining the cell selection criterion does not satisfy the cell selection criterion threshold.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the reference signal parameter satisfies the reference signal threshold when the reference signal parameter may be less than the reference signal threshold, where the received signal parameter satisfies the received signal threshold when the received signal parameter may be less than the received signal threshold, and where the cell selection criterion satisfies the cell selection criterion threshold when the cell selection criterion may be less than the cell selection criterion threshold.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, determining that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter satisfies the received signal threshold, or both may include operations, features, means, or instructions for determining that the reference signal parameter satisfies the reference signal threshold, and determining that the received signal parameter satisfies the received signal threshold.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the cell selection criterion satisfies the cell selection criterion threshold may be based on determining that the reference signal parameter satisfies the reference signal threshold and determining that the received signal parameter satisfies the received signal threshold.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the reference signal parameter includes a RSRP value, a RSRQ value, or both.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the received signal parameter includes an SNR, an SINR, or both.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the cell selection criterion may be based on the reference signal parameter, a minimum RSRP value, a RSRQ value, a minimum RSRQ value, or any combination thereof.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving an input via the UE, where determining that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter associated with the first cell satisfies the received signal threshold, or both, may be based on receiving the input.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for performing a setup procedure for a third cell associated with a third radio access technology based on establishing the connection with the first cell while in the dual connectivity mode of operation.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the third radio access technology includes an NR technology, a 5G technology, or both.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for detaching from the third cell based on establishing the connection with the second cell.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first radio access technology includes a long term evolution technology, a 4G technology, or both, and the second radio access technology includes a 3G technology.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communications system that supports improving cell selection over new radio in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system that supports improving cell selection over new radio in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of a process flow that supports improving cell selection over new radio in accordance with aspects of the present disclosure.

FIGs. 4 and 5 show block diagrams of devices that support improving cell selection over new radio in accordance with aspects of the present disclosure.

FIG. 6 shows a block diagram of a communications manager that supports improving cell selection over new radio in accordance with aspects of the present disclosure.

FIG. 7 shows a diagram of a system including a device that supports improving cell selection over new radio in accordance with aspects of the present disclosure.

FIGs. 8 through 11 show flowcharts illustrating methods that support improving cell selection over new radio in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

In some wireless communications systems, a user equipment (UE) may support dual connectivity (DC) with NR and LTE. The UE may attach to an anchor LTE cell, and may additionally establish a connection with an NR cell. However, in cases where a 3G cell is also available, the UE may detach from the LTE cell (thereby terminating dual connectivity with the NR cell) and attach to the 3G cell when one or more criteria are met. For example, the UE may determine a cell selection criteria based on a reference signal parameter (e.g., reference signal received power (RSRP) value) and one or more additional parameters which are configured by the system/network. In this example, the UE may detach from the LTE cell (and attach to the 3G cell) when the cell selection criteria satisfies a cell selection criterion threshold that is configured by the system/network. After the expiration of a high-priority radio access technology timer, the UE may then detach from the 3G cell, and establish a second connection with the LTE cell. This procedure is intended to improve data transfer at the UE when the performance of the LTE cell does not satisfy given thresholds. This procedure may further result in frequent handovers between the LTE cell and the 3G cell, however, thereby preventing stable addition of a secondary cell group (SCG) and attachment to the NR cell. Furthermore, the frequent handovers between the LTE cell and the 3G cell may result in significant resource and messaging overhead.

To address the frequent handovers between an LTE cell and a 3G cell, a UE may determine to whether switch from the LTE cell to the 3G cell based on one or more reference signal parameters or received signal parameters that can be measured before and potentially in addition to the cell selection criterion. For example, the UE may determine whether an RSRP value, or a signal-to-noise ratio (SNR) associated with the LTE cell, or both satisfy respective threshold values. If one or both of the RSRP value and the SNR associated with the LTE cell do not satisfy the respective threshold, the UE may maintain the connection with the LTE cell in some examples. Comparatively, if one or both of the RSRP value and the SNR associated with the LTE cell satisfy the respective thresholds, the UE may compare a cell selection criterion to a cell selection criterion threshold. The cell selection criterion may be based on the RSRP value and one or more additional parameters configured by the system/network. In cases where the cell selection criterion satisfies the cell selection criterion threshold, the UE may detach from the LTE cell and establish a connection with the 3G cell. Such techniques may provide for stable SCG addition and attachment to an NR cell by providing for an additional determination to be made which is based directly on signals received at the UE (e.g., RSRP, SNR) , thereby preventing frequent handovers between the LTE cell and the 3G cell, and reducing resource and messaging overhead.

Aspects of the disclosure are initially described in the context of wireless communications systems. Aspects of the disclosure are also described in the context of an example process flow. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to recovering user equipment from call failure in new radio.

FIG. 1 illustrates an example of a wireless communications system 100 that supports improving cell selection over new radio in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

The base stations 105 may be dispersed throughout a geographic area to form the wireless communications system 100 and may be devices in different forms or having different capabilities. The base stations 105 and the UEs 115 may wirelessly communicate via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base station 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which a base station 105 and a UE 115 may support the communication of signals according to one or more radio access technologies.

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

The base stations 105 may communicate with the core network 130, or with one another, or both. For example, the base stations 105 may interface with the core network 130 through one or more backhaul links 120 (e.g., via an S1, N2, N3, or other interface) . The base stations 105 may communicate with one another over the backhaul links 120 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) , or indirectly (e.g., via core network 130) , or both. In some examples, the backhaul links 120 may be or include one or more wireless links.

One or more of the base stations 105 described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or other suitable terminology.

A UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client, among other examples. A UE 115 may also include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples.

The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115 that may sometimes act as relays as well as the base stations 105 and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1.

The UEs 115 and the base stations 105 may wirelessly communicate with one another via one or more communication links 125 over one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links 125. For example, a carrier used for a communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP) ) that is operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR) . Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information) , control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communications system 100 may support communication with a UE 115 using carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers.

Signal waveforms transmitted over a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) . In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. A wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams) , and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE 115.

The time intervals for the base stations 105 or the UEs 115 may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of T _s= 1/ (Δf _max·N _f) seconds, where Δf _max may represent the maximum supported subcarrier spacing, and N _f may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms) ) . Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023) .

Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a number of slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on subcarrier spacing. Each slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . In some wireless communications systems 100, a slot may further be divided into multiple mini-slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N _f) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation.

A subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and may be referred to as a transmission time interval (TTI) . In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communications system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) ) .

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

Each base station 105 may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) , or others) . In some examples, a cell may also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) over which the logical communication entity operates. Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the base station 105. For example, a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with geographic coverage areas 110, among other examples.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs 115 with service subscriptions with the network provider supporting the macro cell. A small cell may be associated with a lower-powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to the UEs 115 with service subscriptions with the network provider or may provide restricted access to the UEs 115 having an association with the small cell (e.g., the UEs 115 in a closed subscriber group (CSG) , the UEs 115 associated with users in a home or office) . A base station 105 may support one or multiple cells and may also support communications over the one or more cells using one or multiple component carriers.

In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT) , enhanced mobile broadband (eMBB) ) that may provide access for different types of devices.

In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, the overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous network in which different types of the base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

The wireless communications system 100 may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 may be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications. The UEs 115 may be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission critical functions) . Ultra-reliable communications may include private communication or group communication and may be supported by one or more mission critical services such as mission critical push-to-talk (MCPTT) , mission critical video (MCVideo) , or mission critical data (MCData) . Support for mission critical functions may include prioritization of services, and mission critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission critical, and ultra-reliable low-latency may be used interchangeably herein.

In some examples, a UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol) . One or more UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105 or be otherwise unable to receive transmissions from a base station 105. In some examples, groups of the UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some examples, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between the UEs 115 without the involvement of a base station 105.

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or 5G core (5GC) , which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME) , an access and mobility management function (AMF) ) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs 115 served by the base stations 105 associated with the core network 130. User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to the network operators IP services 150. The operators IP services 150 may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched Streaming Service.

Some of the network devices, such as a base station 105, may include subcomponents such as an access network entity 140, which may be an example of an access node controller (ANC) . Each access network entity 140 may communicate with the UEs 115 through one or more other access network transmission entities 145, which may be referred to as radio heads, smart radio heads, or transmission/reception points (TRPs) . Each access network transmission entity 145 may include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., a base station 105) .

The wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz) . Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length. The UHF waves may be blocked or redirected by buildings and environmental features, but the waves may penetrate structures sufficiently for a macro cell to provide service to the UEs 115 located indoors. The transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

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

A base station 105 or a UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, an antenna panel may support radio frequency beamforming for a signal transmitted via an antenna port.

The base stations 105 or the UEs 115 may use MIMO communications to exploit multipath signal propagation and increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords) . Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) , where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) , where multiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105, a UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that some signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying amplitude offsets, phase offsets, or both to signals carried via the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .

The UEs 115 and the base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. Hybrid automatic repeat request (HARQ) feedback is one technique for increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) . HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., low signal-to-noise conditions) . In some examples, a device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

The UEs 115s and the base stations 105 of the wireless communications system 100 may support communications which may reduce the frequency of unnecessary handovers between a first cell and a second cell. In particular, the wireless communications system 100 may support communications which enable the UEs 115 to measure/compare reference signal parameters or received signal parameters before and in addition to cell selection criterion to reduce the frequency of unnecessary handovers between an LTE cell and a 3G cell. In this regard, the techniques of the present disclosure may provide for an improved cell selection procedure.

For example, in some cases, a UE 115 may be positioned within respective geographic coverage areas 110 of a 3G cell, an LTE cell, and an NR cell. In this regard, the UE 115 may be able to establish connections with each of the 3G cell, the LTE cell, and the NR cell. In some aspects, the UE 115 may establish a connection with a first cell (e.g., first base station 105-a) , such as the LTE cell. In some cases, the first base station 105-a (e.g., LTE cell) may include an anchor LTE cell which also supports the NR cell. In this regard, while operating in a dual connectivity mode of operation, the UE 115 may additionally establish a connection with the NR cell via the first base station 105-a (e.g., anchor LTE cell) .

As part of a cell selection procedure, the UE 115 may determine whether a reference signal parameter associated with the first cell (e.g., LTE cell) satisfies a reference signal threshold. For example, the UE 115 may determine whether an RSRP value associated with the first cell satisfies an RSRP threshold. Additionally or alternatively, the UE 115 may determine whether a received signal parameter associated with the first cell (e.g., LTE cell) satisfies a received signal threshold. For example, the UE 115 may determine whether an SNR value associated with the first cell satisfies an SNR threshold. In cases where the reference signal parameter (e.g., RSRP value) , the received signal parameter (e.g., SNR value) , or both, do not satisfy the respective thresholds, the UE 115 may maintain the connection with the LTE cell.

Comparatively, in cases where the reference signal parameter (e.g., RSRP value) , the received signal parameter (e.g., SNR value) , or both, satisfy the respective thresholds, the UE 115 may determine whether a cell selection criterion associated with the first cell (e.g., LTE cell) satisfies a cell selection criterion threshold. Additionally or alternatively, the UE 115 may determine whether a second cell selection criterion associated with a second cell (e.g., a 3G cell supported by an additional base station 105) satisfies a cell selection criterion threshold. In cases where the cell selection criterion associated with the first cell, the second cell criterion associated with the second cell, or both, do not satisfy the respective thresholds, the UE 115 may maintain the connection with the LTE cell.

However, in cases where the cell selection criterion associated with the first cell, the second cell criterion associated with the second cell, or both, satisfy the respective thresholds, the UE 115 may detach from the first cell (e.g., LTE cell) and establish a connection with the second cell (e.g., 3G cell) . In addition to detaching from the first cell, the UE 115 may additionally detach from the NR cell, thereby terminating the dual connectivity mode of operation at the UE 115. After an expiration of a radio access technology (RAT) timer, the UE 115 may establish a second connection with the first cell (e.g., LTE cell) , and detach from the second cell (e.g., 3G cell) . Upon attaching to the LTE cell, the UE 115 may additionally establish a second connection with the NR cell, thereby successfully adding the SCG and entering the dual connectivity mode of operation.

The techniques described herein may enable the UE to prevent frequent and unnecessary handovers between the first cell and the second cell, thereby improving communication stability and enabling stable secondary cell group (SCG) addition. Moreover, by reducing the number of handovers between cells, the techniques described herein may reduce resource and messaging overhead within the wireless communications system 100.

FIG. 2 illustrates an example of a wireless communications system 200 that supports improving cell selection over new radio in accordance with aspects of the present disclosure. In some examples, wireless communications system 200 may implement aspects of wireless communications system 100. The wireless communications system 200 may include a UE 115-a, a first base station 105-a, and a second base station 105 b, which may be examples of UE 115 and base stations 105, as described with reference to FIG. 1.

The UE 115-a may communicate with the first base station 105-a using a communication link 205-a, and may communicate with the second base station 105-b using a communication link 205-b. In some cases, the communication links 205-a, 205-b may include examples of an access link (e.g., a Uu link) . The communication links 205-a, 205-b may include a bi-directional link that can include both uplink and downlink communication. For example, the UE 115-a may transmit uplink signals, such as uplink control signals or uplink data signals, to the first base station 105-a using the first communication link 205-a and the first base station 105-a may transmit downlink signals, such as downlink control signals or downlink data signals, to the UE 115-a using the communication link 205-a. By way of another example, the UE 115-a may transmit uplink signals, such as uplink control signals or uplink data signals, to the second base station 105-b using the second communication link 205-b and the second base station 105-b may transmit downlink signals, such as downlink control signals or downlink data signals, to the UE 115-a using the communication link 205-b.

The first base station 105-a and the second base station 105-b may communicate with one another via a communication link 205-c. In some cases, the communication link 205-c may include an example of a link between two base stations (e.g., an Xn link) . The first base station 105-a and the second base station 105-b may, in some cases, be collocated. The communication link 205-c may include a bi-directional link.

In some aspects, as noted previously herein, the first base station 105-a and the second base station 105-b may be associated with one or more cells. For example, the first base station 105-a may be associated with a first cell and the second base station 105-b may be associated with a second cell (that is different than the first cell) . For instance, the first base station 105-a may be associated with an LTE cell, an NR cell, or both. In this regard, the communication link 205-a may be an example of an LTE link, an NR/5G link, or both, between the UE 115-a and the first base station 105-a. By way of another example, the second base station 105-b may be associated with a 3G cell. In this regard, the communication link 205-b may be an example of a 3G link between the UE 115-a and the base station 105-b. In some aspects, the first base station 105-a or the second base station 105-b (or both) may facilitate communications between the UE 115-a and the other respective base station 105-a, 105-b. For example, upon establishing a connection with a cell supported by the UE 115-a via the communication link 205-a, the first base station 105-a may carry out communications with the UE 115-a to facilitate the establishment of a connection between the UE 115-a and a cell supported by the second base station 105-b.

As noted herein, in some communications systems where a UE is positioned within a geographic coverage area of a 3G cell, an LTE cell, and a 5G cell, the UE may experience frequent handovers between the LTE cell and the 3G cell. For example, the UE may attach to the LTE cell, and may additionally establish a connection with the NR cell while operating in a dual connectivity mode of operation. However, in cases where the 3G cell is also available, the UE may detach from the LTE cell (thereby terminating dual connectivity with the NR cell) and attach to the 3G cell when one or more criteria are met. This procedure is intended to improve data transfer at the UE when the performance of the LTE cell does not satisfy given thresholds. However, this procedure may further result in frequent handovers, for example, between the LTE cell and the 3G cell, thereby preventing stable addition of an SCG and attachment to the NR cell.

Accordingly, some aspects of the disclosure are directed to techniques which address this issue associated with frequent handovers, for example, between cells. In particular, the wireless communications system 200 may support communications which enable the UE 115-a to determine (e.g., measure, compare) reference signal parameters or received signal parameters before and in addition to cell selection criterion to reduce the frequency of unnecessary handovers, for example, between an LTE cell and a 3G cell.

For example, the UE 115-a may be positioned within respective geographic coverage areas of the first base station 105-a and the second base station 105-b. In this example, the first base station 105-a may support an LTE cell and an NR cell, and the second base station 105-b may support a 3G cell. In this regard, the UE 115-a may be able to establish connections with each of the LTE cell, the NR cell, and the 3G cell via the communication links 205-a and 205-b with the first base station 105-a and the second base station 105-b. In some aspects, the UE 115-a may establish a connection with a first cell (e.g., the LTE cell) via the communication link 205-a and the first base station 105-a. The UE 115-a may establish the connection with the first cell by performing an attach procedure in which the UE 115-a transmits an attach request to the first base station 105-a, and receives an attach accept message from the first base station 105-a.

In some cases, the UE 115-a may additionally establish a connection with the NR cell, for example, supported by the first base station 105-a while operating in a dual connectivity mode of operation (e.g., NSA mode) . For example, the UE 115-a may establish the connection with the NR cell by transmitting an attach request to the first base station 105-a, and receiving an attach accept message from the first base station 105-a.

As part of a cell selection procedure, the UE 115-a may determine whether a reference signal parameter associated with the LTE cell satisfies a reference signal threshold. For example, the UE 115-a may receive a reference signal from the first base station 105-a via the communication link 205-a. The UE 115-a may perform one or more operations (e.g., measurements) on the received reference signal to determine a reference signal parameter, and may, for example, compare the reference signal parameter to a reference signal threshold to determine whether the reference signal parameter satisfies the reference signal threshold. In some aspects, the reference signal parameter may include any one or more reference signal parameters including, but not limited to, an RSRP value, a received signal quality (RSRQ) value, or both.

Additionally or alternatively, as part of the cell selection procedure, the UE 115-a may determine whether a received signal parameter associated with the LTE cell satisfies a received signal threshold. For example, the UE 115-a may receive one or more signals from the first base station 105-a via the communication link 205-a. The UE 115-a may perform one or more measurements on the received signals to determine a received signal parameter, and may compare the received signal parameter to a received signal threshold to determine whether the received signal parameter satisfies the received signal threshold. The received signal parameter may include any one or more received signal parameters including, but not limited to, an SNR value, a signal-to-interference-plus-noise (SINR) value, or both.

In some aspects, the reference signal parameter (e.g., RSRP, RSRQ) and the received signal parameter (e.g., SNR, SINR) associated with the first cell (e.g., LTE cell) may satisfy the respective thresholds when the reference signal parameter (e.g., RSRP, RSRQ) and the received signal parameter (e.g., SNR, SINR) are less than the respective thresholds. Conversely, the reference signal parameter and the received signal parameter associated with the first cell (e.g., LTE cell) may be determined not to satisfy the respective thresholds when the reference signal parameter and the received signal parameter are greater than the respective thresholds.

For example, in cases where the reference signal parameter includes an RSRP value, the RSRP value may satisfy an RSRP threshold when the RSRP value is less than the RSRP threshold. For instance, in some cases, the RSRP threshold may be determined to be -120 dB. In this example, the RSRP value may satisfy the RSRP threshold when the RSRP value associated with the LTE cell is less than -120 dB (e.g., RSRP threshold satisfied when RSRP _ServingCell＜-120 dB) , and the RSRP value may not satisfy the RSRP threshold when the RSRP value associated with the LTE cell is greater than or equal to -120 dB (e.g., RSRP threshold not satisfied when RSRP _ServingCell≥-120 dB) .

By way of another example, in cases where the received signal parameter includes an SNR value, the SNR value may satisfy an SNR threshold when the SNR value is less than the SNR threshold. For instance, in some cases, the SNR threshold may be determined to be 0 dB. In this example, the SNR value may satisfy the SNR threshold when the SNR value associated with the LTE cell is less than 0 dB (e.g., SNR threshold satisfied when SNR _ServingCell＜0 dB) , and the SNR value may not satisfy the SNR threshold when the SNR value associated with the LTE cell is greater than or equal to 0 dB (e.g., SNR threshold not satisfied when SNR _ServingCell≥0 dB) .

In some aspects, the reference signal threshold, the received signal threshold, or both, may be preconfigured, semi-statically configured (e.g., signaled) via the base stations 105-a and 105-b, or dynamically configured (e.g., signaled) by the base stations, 105-a, 105-b. For example, in some cases, the reference signal threshold, the received signal threshold, or both, may be configured (e.g., preconfigured) such that they are stored in a memory of the UE 115-a. In some examples, the reference signal threshold, the received signal threshold, or both, may be indicated to the UE 115-a via signaling from the first base station 105-a over the communication link 205-a. For example, the first base station 105-a may transmit a message to the UE 115-a via the communication link 205-a, where the message includes an indication of the reference signal threshold, the received signal threshold, or both. The message including the indication of the respective thresholds may include, but is not limited to, a system information broadcast (SIB) message, a radio resource control (RRC) message, a synchronization signal block (SSB) message, a configuration message, or downlink control information (DCI) , or any combination thereof.

In some aspects, if the reference signal parameter (e.g., RSRP, RSRQ) , the received signal parameter (e.g., SNR, SINR) , or both, do not satisfy the respective thresholds, the UE 115-a may maintain the connection with the LTE cell, the NR cell, or both. For example, in cases where the reference signal parameter, the received signal parameter, or both, are greater than or equal to the respective thresholds, the UE 115-a may maintain the connection with the LTE cell. In this regard, a reference signal parameter and/or a received signal parameter which is greater than or equal to the respective threshold may be an indication that the connection with the LTE cell exhibits sufficient performance or quality to maintain the connection with the LTE cell and prevent a handover to the 3G cell.

In additional or alternative aspects, if the reference signal parameter (e.g., RSRP, RSRQ) , the received signal parameter (e.g., SNR, SINR) , or both, satisfy the respective thresholds, the UE 115-a may be configured to continue with the cell selection procedure to determine whether the UE 115-a should detach from the LTE cell, the NR cell, or both, and establish a connection with the 3G cell. In this regard, a reference signal parameter and/or a received signal parameter which is less than the respective threshold may be an indication that the connection with the LTE cell exhibits insufficient performance or quality such that the UE 115-a may continue with the cell selection procedure to determine whether the UE 115-a should maintain the connection with the LTE cell (e.g., the serving cell) , or perform a handover to the 3G cell (e.g., the non-serving cell) .

In some aspects, upon determining that the reference signal parameter, the received signal parameter, or both, satisfy the respective thresholds, the UE 115-a may be configured to continue the cell selection procedure and evaluate a cell selection criterion associated with the LTE cell (e.g., the serving cell) . In this regard, the UE 115-a may be configured to determine whether a cell selection criterion associated with the LTE cell satisfies a cell selection criterion threshold based on determining that the reference signal parameter, the received signal parameter, or both, satisfy the respective thresholds.

In some aspects, the cell selection criterion (e.g., S _ServingCell) associated with the first cell (e.g., LTE cell) may satisfy the cell selection criterion threshold (e.g., T _ServingCell) when the cell selection criterion is less than the cell selection criterion threshold (e.g., threshold satisfied when S _ServingCell＜T _ServingCell) . Conversely, the cell selection criterion associated with the first cell (e.g., LTE cell) may be determined not to satisfy the cell selection criterion threshold when the cell selection criterion is greater than or equal to the cell selection criterion threshold (e.g., threshold not satisfied when S _ServingCell≥ T _ServingCell) .

The cell selection criterion may be based on any number of parameters or characteristics which are measured within the wireless communications system 200, configured by the wireless communications system 200, or both. For example, in some aspects, the cell selection criterion may be based on the reference signal parameter associated with the first cell (e.g., RSRP value, RSRQ value) , a minimum RSRP value, a minimum RSRQ value, or any combination thereof. In this regard, the cell selection criterion may be based on measurements performed by the UE 115-a (e.g., measurements to determine RSRP value, RSRQ value) as well as one or more additional parameters configured by the wireless communications system 200 (e.g., minimum RSRP value, minimum RSRQ value) . In some aspects, the one or more additional parameters which are included within the determination of the cell selection criterion may be indicated to the UE 115-a via signaling from the first base station 105-a. For example, the first base station 105-a may transmit an SIB message to the UE 115-a including an indication of one or more additional parameters to be used for the determination of the cell selection criterion. In this example, the UE 115-a may be configured to determine the cell selection criterion associated with the first cell based on the indication of the one or more additional parameters, based on measurements performed at the UE 115-a, or both.

Similarly, in some aspects, the cell selection criterion threshold may be preconfigured, semi-statically configured/signaled via the first base station 105-a, or dynamically configured/signaled by the first base station 105-a. For example, in some cases, the cell selection criterion threshold may be indicated to the UE 115-a via signaling from the first base station 105-a over the communication link 205-a. For instance, the first base station 105-a may transmit a message to the UE 115-a via the communication link 205-a, where the message includes an indication of the cell selection criterion threshold. The message including the indication of the cell selection criterion threshold may include, but is not limited to, an SIB message, an RRC message, an SSB message, a configuration message, or DCI.

In additional or alternative aspects, upon determining that the reference signal parameter, the received signal parameter, or both, satisfy the respective thresholds, the UE 115-a may be configured to continue the cell selection procedure and evaluate a second cell selection criterion associated with the 3G cell. In this regard, the UE 115-a may be configured to determine whether a second cell selection criterion associated with the 3G cell satisfies a second cell selection criterion threshold based on determining that the reference signal parameter, the received signal parameter, or both, satisfy the respective thresholds.

In some aspects, the second cell selection criterion (e.g., S _{NonServingCell}) associated with the second cell (e.g., 3G cell, or non-serving cell) may satisfy the cell selection criterion threshold (e.g., T _{NonServingCell}) when the second cell selection criterion is greater than the second cell selection criterion threshold (e.g., threshold satisfied when S _{NonServingCell}＞T _{NonServingCell}) . Conversely, the second cell selection criterion associated with the second cell (e.g., 3G cell) may be determined not to satisfy the second cell selection criterion threshold when the second cell selection criterion is less or equal to than the second cell selection criterion threshold (e.g., threshold not satisfied when S _{NonServingCell}≤ T _{NonServingCell}) .

As noted previously herein with respect to the cell selection criterion (e.g., S _ServingCell) associated with the first cell (e.g., LTE cell, or serving cell) , the second cell selection criterion (e.g., S _{NonServingCell}) associated with the second cell (e.g., 3G cell, or non-serving cell) may be based on any number of parameters or characteristics which are measured within the wireless communications system 200, configured by the wireless communications system 200, or both. For example, in some aspects, the second cell selection criterion may be based on a reference signal parameter associated with the 3G cell (e.g., RSRP value, RSRQ value) , a minimum RSRP value, a minimum RSRQ value, or any combination thereof. In this regard, the second cell selection criterion may be based on measurements performed by the UE 115-a (e.g., measurements to determine RSRP value, RSRQ value) associated with the 3G cell, as well as one or more additional parameters configured by the wireless communications system 200 (e.g., minimum RSRP value, minimum RSRQ value) . In some aspects, the one or more additional parameters which are included within the determination of the second cell selection criterion may be indicated to the UE 115-a via signaling from the second base station 105-b.

For example, the second base station 105-b may transmit a SIB message to the UE 115-a including an indication of one or more additional parameters to be used for the determination of the second cell selection criterion. In this example, the UE 115-a may be configured to determine the second cell selection criterion associated with the first cell based on the indication of the one or more additional parameters, based on measurements performed at the UE 115-a based on the communication link 205-b, or both.

Similarly, in some aspects, the second cell selection criterion threshold associated with the second cell (e.g., 3G cell) may be preconfigured, semi-statically configured/signaled via the second base stations 105-b, or dynamically configured/signaled by the second base station 105-b. For example, in some cases, the second cell selection criterion threshold may be indicated to the UE 115-a via signaling from the second base station 105-b over the communication link 205-b. For instance, the second base station 105-b may transmit a message to the UE 115-a via the communication link 205-b, where the message includes an indication of the second cell selection criterion threshold. The message including the indication of the second cell selection criterion threshold may include, but is not limited to, an SIB message, an RRC message, an SSB message, a configuration message, or DCI, or any combination thereof.

In some aspects, if the cell selection criterion associated with the first cell (e.g., LTE cell) , the second cell selection criterion associated with the second cell (e.g., 3G cell) , or both, do not satisfy the respective thresholds, the UE 115-a may maintain the connection with the LTE cell, the NR cell, or both. For example, in cases where the cell selection criterion associated with the first cell (e.g., LTE cell) is greater than the cell selection criterion threshold (e.g., S _ServingCell＞T _ServingCell) ., the UE 115-a may maintain the connection with the LTE cell. By way of another example, in cases where the second cell selection criterion associated with the second cell (e.g., 3G cell) is less than the second cell selection criterion threshold (e.g., S _{NonServingCell}＜T _{NonServingCell}) ., the UE 115-a may maintain the connection with the LTE cell. In some cases, both the cell selection criterion threshold associated with the first cell (e.g., LTE cell) and the second cell selection criterion threshold associated with the second cell (e.g., 3G cell) may satisfy the respective thresholds for the UE 115-a to maintain the connection with the LTE cell.

In additional or alternative aspects, if the cell selection criterion associated with the first cell (e.g., LTE cell) , the second cell selection criterion associated with the second cell (e.g., 3G cell) , or both, or both, satisfy the respective thresholds, the UE 115-a may detach from the LTE cell, the NR cell, or both, and establish a connection with the 3G cell. For example, in cases where the cell selection criterion associated with the LTE cell is less than the cell selection criterion threshold, or the second cell selection criterion is greater than the second cell selection criterion threshold, or both, the UE 115-a may detach from the LTE cell, the NR cell, or both, and establish a connection with the 3G cell. The UE 115-a may establish the connection with the 3G cell by, for example, performing an attach procedure in which the UE 115-a transmits an attach request to the second base station 105-b, and receives an attach accept message from the second base station 105-b.

In some aspects, the UE 115-a may initiate a timer, such as a RAT timer, upon detaching from the LTE cell, upon attaching to the 3G cell, or both. The UE 115-a may be configured to determine an expiration of the RAT timer based on initiating the RAT timer and a timer duration, and may re-attach to the LTE cell based on the expiration of the RAT timer. In this regard, upon expiration of the RAT timer, the UE 115-a may detach from the 3G cell, and establish a second connection with the LTE cell. Additionally, the UE 115-a may establish a second connection with the NR cell based on establishing the connection with the LTE cell to operate in the dual connectivity mode of operation.

The techniques described herein may prevent frequent and unnecessary handovers between a first cell (e.g., LTE cell) and a second cell (e.g., 3G cell) , thereby improving communication stability and enabling stable secondary cell group (SCG) addition (e.g., addition of the NR cell) . Moreover, by reducing the number of handovers between cells, the techniques described herein may reduce resource and messaging overhead within the wireless communications system 200.

FIG. 3 illustrates an example of a process flow 300 that supports improving cell selection over new radio in accordance with aspects of the present disclosure. In some examples, process flow 300 may implement or may be implemented by aspects of

wireless communications system

100 or 200. For example, the process flow 300 may illustrate establishing a connection with a first cell associated with a first radio access technology, determining whether a reference signal parameter and a received signal parameter satisfy respective thresholds, determining whether a cell selection criterion satisfies a threshold, and establishing a connection with a second cell associated with a second radio access technology, as described with reference to FIGs. 1–2, among other aspects.

In some cases, process flow 300 may be related to or be performed by a UE 115-b, a base station 105-c, or a base station 105-d, or any combination thereof, which may be examples of corresponding devices as described herein. In particular, the UE 115-b illustrated in FIG. 3 may be an example of the UE 115-a illustrated in FIG. 2. In some aspects, the base station 105-c may support an LTE cell, an NR cell, or both, and the base station 105-d may support a 3G cell. In this regard, the base stations 105-c and 105-d illustrated in FIG. 3 may be examples of the first base station 105-a and the second base station 105-b illustrated in FIG. 2.

In some examples, the operations illustrated in process flow 300 may be performed by hardware (e.g., including circuitry, processing blocks, logic components, and other components) , code (e.g., software or firmware) executed by a processor, or any combination thereof. Alternative examples of the following may be implemented, where some steps are performed in a different order than described or are not performed at all. In some cases, steps may include additional features not mentioned below, or further steps may be added.

At 305, the UE 115-b may establish a first connection with a first cell associated with a first radio access technology (e.g., 4G cell, LTE cell) . In some aspects, the UE 115-b may establish the first connection with the first cell while operating in a dual connectivity mode of operation and/or an NSA mode of operation. In some aspects, the UE 115-b may establish the first connection with the first cell associated with the base station 105-c via the communication link 205-a illustrated in FIG. 2. In some aspects, the UE 115-b may establish the first connection with the first cell associated with the base station 105-c by performing an attachment procedure. For example, the UE 115-b may transmit an attach request message to the base station 105-c, and the base station 105-c may transmit an attach accept message to the UE 115-b in response to the attach request message. In this example, the UE 115-b may establish the first connection with the first cell based on receiving the attach accept message.

At 310, the UE 115-b may establish a second connection with a second cell associated with a second radio access technology (e.g., NR cell, 5Gcell) . In some aspects, the UE 115-b may establish the second connection with the second cell based on establishing the connection with the first cell while operating in a dual connectivity mode of operation and/or an NSA mode of operation. In some aspects, the UE 115-b may establish the second connection with the second cell associated with the base station 105-c via the communication link 205-a illustrated in FIG. 2. In some aspects, the UE 115-b may establish the second connection with the second cell associated with the base station 105-c by performing an attachment procedure. For example, the UE 115-b may transmit an attach request message to the base station 105-c, and the base station 105-c may transmit an attach accept message to the UE 115-b in response to the attach request message. In this example, the UE 115-b may establish the first connection with the second cell based on receiving the attach accept message.

At 315, the base station 105-c may transmit one or more messages including an indication of a reference signal threshold associated with the LTE cell, a received signal threshold associated with the LTE cell, or both. The message transmitted at 315 may include, but is not limited to, an SIB message, an RRC message, an SSB message, a configuration message, DCI, or any combination thereof, and the like. The message transmitted by the base station 105-c at 315 may include an indication of a threshold associated with any reference signal parameter including, but not limited to, an RSRP threshold, an RSRQ threshold, or any combination thereof, and the like. Moreover, the message transmitted by the base station 105-c at 315 may additionally or alternatively include an indication of a threshold associated with any received signal parameter including, but not limited to, an SNR threshold, an SINR threshold, or any combination thereof, and the like.

At 320, the UE 115-b may perform one or more measurements on signals received from the base station 105-c in order to determine a reference signal parameter associated with the LTE cell, a received signal parameter associated with the LTE cell, or both. The UE 115-b may be configured to perform the measurements in order to determine given reference signal parameters, received signal parameters, or both, based on the message including the indication of the thresholds received at 315. For example, the UE 115-b may perform one or more measurements to determine an RSRP value, an RSRQ value, or any combination thereof, and the like. Similarly, the UE 115-b ma perform one or more measurements to determine an SNR value, an SINR value, or any combination thereof, and the like.

At 325, the UE 115-b may determine whether the reference signal parameter and/or the received signal parameter satisfy respective thresholds. In some aspects, the UE 115-b may determine that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter satisfies the received signal threshold, or both, based on the message including the indication of the respective thresholds received at 315. For example, in some cases, the message received at 315 may include an indication of an RSRP threshold, an SNR threshold, or both. In this example, the UE 115-b may determine whether an RSRP value satisfies an RSRP threshold, and may additionally or alternatively determine whether the SNR value satisfies an SNR threshold based on the message including the indications received at 315.

In some aspects, the reference signal parameter (e.g., RSRP, RSRQ) and the received signal parameter (e.g., SNR, SINR) associated with the first cell (e.g., LTE cell) may satisfy the respective thresholds when the reference signal parameter (e.g., RSRP, RSRQ) and the received signal parameter (e.g., SNR, SINR) are less than the respective thresholds. Conversely, the reference signal parameter (e.g., RSRP, RSRQ) and the received signal parameter (e.g., SNR, SINR) associated with the first cell (e.g., LTE cell) may be determined not to satisfy the respective thresholds when the reference signal parameter (e.g., RSRP, RSRQ) and the received signal parameter (e.g., SNR, SINR) are greater than or equal to the respective thresholds.

In some aspects, if the reference signal parameter (e.g., RSRP, RSRQ) , the received signal parameter (e.g., SNR, SINR) , or both, do not satisfy the respective thresholds (e.g., step 325 is “NO” ) , the UE 115-a may maintain the connection with the LTE cell, the NR cell, or both. For example, in cases where the reference signal parameter, the received signal parameter, or both, are greater than or equal to the respective thresholds, the UE 115-b may maintain the connection with the LTE cell. In some aspects, upon determining that the reference signal parameter and/or the received signal parameter do not satisfy the respective thresholds, the process flow 300 may proceed to 320. In some aspects, the UE 115-b may be configured to perform the measurements at 320 and the determination at 325 at regular or irregular intervals.

In additional or alternative aspects, if the reference signal parameter (e.g., RSRP, RSRQ) , the received signal parameter (e.g., SNR, SINR) , or both, satisfy the respective thresholds (e.g., step 325 is “YES” ) , the UE 115-a may be configured to continue with the cell selection procedure, and the process flow 300 may continue to 330. In some aspects, only one of the reference signal parameter or the received signal parameter may be required to satisfy the respective threshold for the UE 115-b to determine “YES” at 325. In additional or alternative aspects, both the reference signal parameter and the received signal parameter may be required satisfy the respective thresholds for the UE 115-b to determine “YES” at 325. It is further noted herein that the UE 115-b may be configured to compare any number of reference signal parameters, received signal parameters, or both, at 325 with respective thresholds, and that any number of the parameters may be required to satisfy the respective thresholds for the UE 115-b to determine “YES” at 325.

At 330, the base station 105-c may transmit a message including an indication of a cell selection threshold associated with the LTE cell (e.g., T _ServingCell) . Similarly, at 335, the base station 105-d may transmit a message including an indication of a second cell selection threshold associated with the 3G cell (e.g., T _{NonServingCell}) . The messages transmitted at 330 and 335 may include, but are not limited to, SIB messages, RRC messages, SSB messages, configuration messages, DCI, or any combination thereof, and the like.

At 340, the UE 115-b may determine whether a cell selection criterion associated with the LTE cell (e.g., S _ServingCell) , a second cell selection criterion associated with the 3G cell (e.g., S _{NonServingCell}) , or both, satisfy the respective thresholds (e.g., T _ServingCell, T _{NonServingCell}) . In this regard, the UE 115-b may determine whether the cell selection criterion associated with the LTE cell (e.g., S _ServingCell) satisfies the cell selection criterion threshold associated with the LTE cell (e.g., T _ServingCell) , and/or whether the second cell selection criterion associated with the 3G cell (e.g., S _{NonServingCell}) satisfies the second cell selection criterion threshold associated with the 3G cell (e.g., T _ServingCell) . In some aspects, the UE 115-b may determine that the cell selection criterion associated with the LTE cell, the second cell selection criterion associated with the 3G cell, or both, satisfy the respective thresholds based on the messages including the indications of the respective thresholds received at 330 and 335.

The cell selection criterion associated with the LTE cell and/or 3G cell may be based on any number (e.g., one or more) of parameters or characteristics. For example, in some aspects, the cell selection criterion may be based on the reference signal parameters associated with the respective cells (e.g., RSRP value, RSRQ value) , a minimum RSRP value, a minimum RSRQ value, or any combination thereof. In this regard, the cell selection criterion may be based on measurements performed by the UE 115-b (e.g., measurements to determine RSRP value, RSRQ value) as well as one or more additional parameters (e.g., minimum RSRP value, minimum RSRQ value) . In some aspects, the messages transmitted at 330 and 335 may include an indication of the one or more additional parameters which are included within the determination of the respective cell selection criterion.

In some aspects, the second cell selection criterion (e.g., S _{NonServingCell}) associated with the second cell (e.g., 3G cell) may satisfy the cell selection criterion threshold (e.g., T _{NonServingCell}) when the second cell selection criterion is greater than the second cell selection criterion threshold (e.g., threshold satisfied when S _{NonServingCell}＞T _{NonServingCell}) . Conversely, the second cell selection criterion associated with the second cell (e.g., 3G cell) may be determined not to satisfy the second cell selection criterion threshold when the second cell selection criterion is less or equal to than the second cell selection criterion threshold (e.g., threshold not satisfied when S _{NonServingCell}≤T _{NonServingCell}) .

In some aspects, if the cell selection criterion associated with the first cell (e.g., LTE cell) , the second cell selection criterion associated with the second cell (e.g., 3G cell) , or both, do not satisfy the respective thresholds (e.g., step 340 is “NO” ) , the UE 115-a may maintain the connection with the LTE cell, the NR cell, or both. For example, in cases where the cell selection criterion associated with the first cell (e.g., LTE cell) is greater than the cell selection criterion threshold (e.g., S _ServingCell＞T _ServingCell) ., the UE 115-b may maintain the connection with the LTE cell. By way of another example, in cases where the second cell selection criterion associated with the second cell (e.g., 3G cell) is less than the second cell selection criterion threshold (e.g., S _{NonServingCell}＜T _{NonServingCell}) ., the UE 115-b may maintain the connection with the LTE cell. In some cases, both the cell selection criterion threshold associated with the first cell (e.g., LTE cell) and the second cell selection criterion threshold associated with the second cell (e.g., 3G cell) may satisfy the respective thresholds for the UE 115-a to maintain the connection with the LTE cell. In some aspects, the UE 115-b may be configured to perform the determination at 340 at regular or irregular intervals.

In additional or alternative aspects, if the cell selection criterion associated with the first cell (e.g., LTE cell) , the second cell selection criterion associated with the second cell (e.g., 3G cell) , or both, satisfy the respective thresholds (e.g., step 340 is “YES” ) , the process flow 300 may proceed to 345.

At 345, the UE 115-b may establish a connection with the 3G cell. In some aspects, the UE 115-b may establish the connection with the 3G cell based on determining cell selection criterion associated with the first cell (e.g., LTE cell) , the second cell selection criterion associated with the second cell (e.g., 3G cell) , or both, satisfy the respective thresholds. The UE 115-b may establish the connection with the 3G cell by performing an attach procedure in which the UE 115-b transmits an attach request message to the base station 105-d, and receives an attach accept message from the second base station 105-d.

In some aspects, the UE 115-b may additionally detach from the LTE cell, the NR cell, or both. The UE 115-b may detach from the LTE cell, the NR cell, or both, upon establishing the connection with the 3G cell and/or upon determining that the cell selection criterion associated with the first cell (e.g., LTE cell) , the second cell selection criterion associated with the second cell (e.g., 3G cell) , or both, satisfy the respective thresholds. For example, upon determining “YES” at 340, the UE 115-b may transmit a detach request message to the base station 105-c, and receive a detach accept message from the base station 105-c. The UE 115-b may detach from the LTE cell, the NR cell, or both, based on receiving the detach accept message from the base station 105-c.

At 350, the UE 115-b may determine whether a RAT timer has expired. In some aspects, the RAT timer may be utilized to determine when the UE 115-b should perform a handover from a cell associated with a lower priority RAT (e.g., 3G cell) to a cell associated with a higher priority RAT (e.g., LTE cell) . For example, the UE 115-b may initiate the RAT timer based on establishing the connection with the 3G cell at 345 (and/or detaching from the LTE cell) . In some aspects, the RAT timer may include a timer duration for which the RAT timer is to run. The timer duration of the RAT timer may be preconfigured, signaled to the UE 115-b via a configuration message, and the like. In this example, the UE 115-b may determine whether the RAT timer has expired based on initiating the RAT timer and the timer duration. If the UE 115-b determines that the RAT timer has not expired (e.g., step 350 is “NO” ) , the UE 115-b may continue to monitor and determine whether the RAT timer has expired at regular or irregular intervals. If the UE 115-b determines that the RAT timer has expired (e.g., step 355 is “YES” ) , process flow 300 may proceed to 355.

At 355, the UE 115-b may establish a second connection with the LTE cell. In some aspects, the UE 115-b may establish the second connection with the LTE cell based on the expiration of the RAT timer. In some aspects, the UE 115-b may establish the second connection with the LTE cell associated with the base station 105-c by performing an attachment procedure. For example, the UE 115-b may transmit an attach request message to the base station 105-c, and the base station 105-c may transmit an attach accept message to the UE 115-b in response to the attach request message. In some aspects, the UE 115-b may establish the second connection with the LTE cell based on the attach accept message.

At 360, the UE 115-b may establish a second connection with the NR cell. In some aspects, the UE 115-b may establish the second connection with the NR cell based on the expiration of the RAT timer. Additionally or alternatively, the UE 115-b may establish the second connection with the NR cell based on establishing the second connection with the LTE cell and operating in the dual connectivity mode of operation. In some aspects, the UE 115-b may establish the second connection with the NR cell associated with the base station 105-c by performing an attachment procedure. For example, the UE 115-b may transmit an attach request message to the base station 105-c, and the base station 105-c may transmit an attach accept message to the UE 115-b in response to the attach request message. In some aspects, the UE 115-b may establish the second connection with the NR cell based on the attach accept message.

In additional or alternative aspects, a user of the UE 115-b may be able to control (e.g. provide feedback about or select a mode related to) or determine whether the UE 115-b is to perform a cell selection procedure according to the process flow 300 or according to other cell selection techniques. For example, the UE 115-b may receive an input (e.g., user input, user command) from a user, where the input includes an indication as to whether or not the UE 115-b should perform a cell selection procedure according to the process flow 300 or according to other cell selection techniques. For instance, upon receiving an input via the UE 115-b, the UE 115-b may be configured to determine that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter associated with the first cell satisfies the received signal threshold, or both, based on receiving the input. In this regard, the UE 115-b may be configured to perform the measurements and determinations at 320 and 325 based on receiving the input (e.g., user input) via the UE 115-b.

FIG. 4 shows a block diagram 400 of a device 405 that supports improving cell selection over new radio in accordance with aspects of the present disclosure. The device 405 may be an example of aspects of a UE 115 as described herein. The device 405 may include a receiver 410, a communications manager 415, and a transmitter 420. The device 405 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 410 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to improving cell selection over new radio, etc. ) . Information may be passed on to other components of the device 405. The receiver 410 may be an example of aspects of the transceiver 720 described with reference to FIG. 7. The receiver 410 may utilize a single antenna or a set of antennas.

The communications manager 415 may establish a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation. The communications manager 415 may establish a connection with a second cell associated with a second radio access technology based on determining that the cell selection criterion satisfies the cell selection criterion threshold. The communications manager 415 may determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both. The communications manager 415 may determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both. The communications manager 415 may be an example of aspects of the communications manager 710 described herein.

The actions performed by the communications manager 415 as described herein may be implemented to realize one or more potential advantages. For example, reducing the number of unnecessary handovers between a first cell (e.g., LTE cell) and a second cell (e.g., 3G cell) at a UE 115 may improve the efficiency and reliability of wireless communications. In particular, reducing the number of handovers may reduce network overhead and signaling associated with the handover procedures. Moreover, reducing the number of handover procedures performed by the UE 115 may reduce power consumption at the UE 115, and provide for more stable SCG addition.

By comparing signal parameters (e.g., reference signal parameters, received signal parameters) to respective thresholds when performing a cell selection procedure, a processor of the UE 115 (e.g., a processor controlling the receiver 410, the communications manager 415, the transmitter 420, etc. ) may reduce processing resources associated with performing frequent handover procedures. For example, by comparing reference signal parameters, received signal parameters, or both, to respective thresholds when performing a cell selection procedure, the UE 115 may reduce the number of handover procedures performed at the UE 115, thereby reducing processing resources associated with the handover procedures. Reducing the number of handover procedures may reduce the signaling required between the UE 115 and the base stations 105, correspondingly reducing a number of times the processor ramps up processing power and turns on processing units to handle signal reception and transmission.

The communications manager 415, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 415, or its sub-components may be executed by a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

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

The transmitter 420 may transmit signals generated by other components of the device 405. In some examples, the transmitter 420 may be collocated with a receiver 410 in a transceiver module. For example, the transmitter 420 may be an example of aspects of the transceiver 720 described with reference to FIG. 7. The transmitter 420 may utilize a single antenna or a set of antennas.

FIG. 5 shows a block diagram 500 of a device 505 that supports improving cell selection over new radio in accordance with aspects of the present disclosure. The device 505 may be an example of aspects of a device 405, or a UE 115 as described herein. The device 505 may include a receiver 510, a communications manager 515, and a transmitter 535. The device 505 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to improving cell selection over new radio, etc. ) . Information may be passed on to other components of the device 505. The receiver 510 may be an example of aspects of the transceiver 720 described with reference to FIG. 7. The receiver 510 may utilize a single antenna or a set of antennas.

The communications manager 515 may be an example of aspects of the communications manager 415 as described herein. The communications manager 515 may include a cell connection manager 520, a signal parameter manager 525, and a cell selection parameter manager 530. The communications manager 515 may be an example of aspects of the communications manager 710 described herein.

The cell connection manager 520 may establish a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation. The cell connection manager 520 may establish a connection with a second cell associated with a second radio access technology based on determining that the cell selection criterion satisfies the cell selection criterion threshold.

The signal parameter manager 525 may determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both. The cell selection parameter manager 530 may determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both.

The transmitter 535 may transmit signals generated by other components of the device 505. In some examples, the transmitter 535 may be collocated with a receiver 510 in a transceiver module. For example, the transmitter 535 may be an example of aspects of the transceiver 720 described with reference to FIG. 7. The transmitter 535 may utilize a single antenna or a set of antennas.

FIG. 6 shows a block diagram 600 of a communications manager 605 that supports improving cell selection over new radio in accordance with aspects of the present disclosure. The communications manager 605 may be an example of aspects of a communications manager 415, a communications manager 515, or a communications manager 710 described herein. The communications manager 605 may include a cell connection manager 610, a signal parameter manager 615, a cell selection parameter manager 620, a RAT timer manager 625, an attach request transmitting manager 630, an attach accept receiving manager 635, a SIB message receiving manager 640, a message receiving manager 645, an user input manager 650, a setup procedure manager 655, and a detach procedure manager 660. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The signal parameter manager 615 may determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both. In some examples, the signal parameter manager 615 may determine that the reference signal parameter does not satisfy the reference signal threshold, or that the received signal parameter does not satisfy the received signal threshold, or both. In some cases, the received signal parameter satisfies the received signal threshold when the received signal parameter is less than the received signal threshold.

In some examples, the signal parameter manager 615 may determine that the reference signal parameter satisfies the reference signal threshold. In some examples, the signal parameter manager 615 may determine that the received signal parameter satisfies the received signal threshold. In some cases, the reference signal parameter satisfies the reference signal threshold when the reference signal parameter is less than the reference signal threshold. In some cases, the reference signal parameter includes a reference signal received power value, a reference signal received quality value, or both. In some cases, the received signal parameter includes a signal-to-noise ratio, a signal-to-interference-plus noise ratio, or both.

The cell selection parameter manager 620 may determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both. In some examples, the cell selection parameter manager 620 may determine that a second cell selection criterion associated with the second cell satisfies a second cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both. In some examples, the cell selection parameter manager 620 may establishing the connection with the second cell is based on the second cell selection criterion associated with the second cell satisfying the second cell selection criterion threshold. In some examples, the cell selection parameter manager 620 may determine that the cell selection criterion does not satisfy the cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both.

In some aspects, the cell selection criterion satisfies the cell selection criterion threshold when the cell selection criterion is less than the cell selection criterion threshold. In some examples, the cell selection parameter manager 620 may determine that the cell selection criterion satisfies the cell selection criterion threshold is based on determining that the reference signal parameter satisfies the reference signal threshold and determining that the received signal parameter satisfies the received signal threshold. In some cases, the second cell selection criterion associated with the second cell satisfies the second cell selection criterion threshold when the second cell selection criterion is greater than the second cell selection criterion threshold. In some cases, the cell selection criterion is based on the reference signal parameter, a minimum reference signal received power value, a reference signal received quality value, a minimum reference signal received quality value, or any combination thereof.

In some examples, the cell connection manager 610 may maintain the connection with the first cell based on determining that the reference signal parameter does not satisfy the reference signal threshold, or that the received signal parameter does not satisfy the received signal threshold, or both. In some examples, the cell connection manager 610 may maintain the connection with the first cell based on determining the cell selection criterion does not satisfy the cell selection criterion threshold.

In some examples, the cell connection manager 610 may establish a connection with a second cell associated with a second radio access technology based on determining that the cell selection criterion satisfies the cell selection criterion threshold. In some examples, the cell connection manager 610 may detach from the first cell based on establishing the connection with the second cell. In some examples, the cell connection manager 610 may establish the second connection with the first cell associated with the first radio access technology based on the attach accept message.

In some cases, the third radio access technology includes a new radio technology, a fifth generation (5G) technology, or both. In some cases, the first radio access technology includes a long term evolution technology, a fourth generation (4G) technology, or both. In some cases, the second radio access technology includes a third generation (3G) technology.

The RAT timer manager 625 may determine that a radio access technology timer has expired. In some examples, the RAT timer manager 625 may initiate the radio access technology timer based on establishing the connection with the second cell associated with the second radio access technology. In some examples, the RAT timer manager 625 may determine that the radio access technology timer has expired based on initiating the radio access technology timer and a timer duration.

The attach request transmitting manager 630 may transmit, to a base station supporting the first cell, an attach request message for a second connection with the first cell based on determining that the radio access technology timer has expired. The attach accept receiving manager 635 may receive, from the base station supporting the first cell, an attach accept message, where the attach accept message is received based on the attach request message. The cell connection manager 610 may establish a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation.

The SIB message receiving manager 640 may receive, from a base station supporting the first cell, a system information broadcast message including an indication of the cell selection criterion threshold, where determining that the cell selection criterion satisfies the cell selection criterion threshold is based on receiving the system information broadcast message. The message receiving manager 645 may receive, from a base station supporting the first cell, at least one of a system information broadcast message, a radio resource control message, a synchronization signal block message, a configuration message, or downlink control information including an indication of at least one of the reference signal threshold or the received signal threshold, where determining that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter satisfies the received signal threshold, or both, is based on receiving the at least one of the system information broadcast message, the radio resource control message, the synchronization signal block message, the configuration message, or the downlink control information including the indication.

The user input manager 650 may receive an input via the UE, where determining that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter associated with the first cell satisfies the received signal threshold, or both, is based on receiving the input.

The setup procedure manager 655 may perform a setup procedure for a third cell associated with a third radio access technology based on establishing the connection with the first cell while in the dual connectivity mode of operation. The detach procedure manager 660 may detach from the third cell based on establishing the connection with the second cell.

FIG. 7 shows a diagram of a system 700 including a device 705 that supports improving cell selection over new radio in accordance with aspects of the present disclosure. The device 705 may be an example of or include the components of device 405, device 505, or a UE 115 as described herein. The device 705 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 710, an I/O controller 715, a transceiver 720, an antenna 725, memory 730, and a processor 740. These components may be in electronic communication via one or more buses (e.g., bus 745) .

The communications manager 710 may establish a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation. The communications manager 710 may establish a connection with a second cell associated with a second radio access technology based on determining that the cell selection criterion satisfies the cell selection criterion threshold. The communications manager 710 may determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both. The communications manager 710 may determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both.

The I/O controller 715 may manage input and output signals for the device 705. The I/O controller 715 may also manage peripherals not integrated into the device 705. In some cases, the I/O controller 715 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 715 may utilize an operating system such as

or another known operating system. In other cases, the I/O controller 715 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 715 may be implemented as part of a processor. In some cases, a user may interact with the device 705 via the I/O controller 715 or via hardware components controlled by the I/O controller 715.

The transceiver 720 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 720 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 720 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 725. However, in some cases the device may have more than one antenna 725, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

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

The processor 740 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 740 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor 740. The processor 740 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 730) to cause the device 705 to perform various functions (e.g., functions or tasks supporting improving cell selection over new radio) .

The code 735 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 735 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 735 may not be directly executable by the processor 740 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 8 shows a flowchart illustrating a method 800 that supports improving cell selection over new radio in accordance with aspects of the present disclosure. The operations of method 800 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 800 may be performed by a communications manager as described with reference to FIGs. 4 through 7. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 805, the UE may establish a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation. The operations of 805 may be performed according to the methods described herein. In some examples, aspects of the operations of 805 may be performed by a cell connection manager as described with reference to FIGs. 4 through 7.

At 810, the UE may determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both. The operations of 810 may be performed according to the methods described herein. In some examples, aspects of the operations of 810 may be performed by a signal parameter manager as described with reference to FIGs. 4 through 7.

At 815, the UE may determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both. The operations of 815 may be performed according to the methods described herein. In some examples, aspects of the operations of 815 may be performed by a cell selection parameter manager as described with reference to FIGs. 4 through 7.

At 820, the UE may establish a connection with a second cell associated with a second radio access technology based on determining that the cell selection criterion satisfies the cell selection criterion threshold. The operations of 820 may be performed according to the methods described herein. In some examples, aspects of the operations of 820 may be performed by a cell connection manager as described with reference to FIGs. 4 through 7.

FIG. 9 shows a flowchart illustrating a method 900 that supports improving cell selection over new radio in accordance with aspects of the present disclosure. The operations of method 900 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 900 may be performed by a communications manager as described with reference to FIGs. 4 through 7. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 905, the UE may establish a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation. The operations of 905 may be performed according to the methods described herein. In some examples, aspects of the operations of 905 may be performed by a cell connection manager as described with reference to FIGs. 4 through 7.

At 910, the UE may determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both. The operations of 910 may be performed according to the methods described herein. In some examples, aspects of the operations of 910 may be performed by a signal parameter manager as described with reference to FIGs. 4 through 7.

At 915, the UE may determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both. The operations of 915 may be performed according to the methods described herein. In some examples, aspects of the operations of 915 may be performed by a cell selection parameter manager as described with reference to FIGs. 4 through 7.

At 920, the UE may establish a connection with a second cell associated with a second radio access technology based on determining that the cell selection criterion satisfies the cell selection criterion threshold. The operations of 920 may be performed according to the methods described herein. In some examples, aspects of the operations of 920 may be performed by a cell connection manager as described with reference to FIGs. 4 through 7.

At 925, the UE may determine that a radio access technology timer has expired. The operations of 925 may be performed according to the methods described herein. In some examples, aspects of the operations of 925 may be performed by a RAT timer manager as described with reference to FIGs. 4 through 7.

At 930, the UE may transmit, to a base station supporting the first cell, an attach request message for a second connection with the first cell based on determining that the radio access technology timer has expired. The operations of 930 may be performed according to the methods described herein. In some examples, aspects of the operations of 930 may be performed by an attach request transmitting manager as described with reference to FIGs. 4 through 7.

At 935, the UE may receive, from the base station supporting the first cell, an attach accept message, where the attach accept message is received based on the attach request message. The operations of 935 may be performed according to the methods described herein. In some examples, aspects of the operations of 935 may be performed by an attach accept receiving manager as described with reference to FIGs. 4 through 7.

At 940, the UE may establish the second connection with the first cell associated with the first radio access technology based on the attach accept message. The operations of 940 may be performed according to the methods described herein. In some examples, aspects of the operations of 940 may be performed by a cell connection manager as described with reference to FIGs. 4 through 7.

FIG. 10 shows a flowchart illustrating a method 1000 that supports improving cell selection over new radio in accordance with aspects of the present disclosure. The operations of method 1000 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1000 may be performed by a communications manager as described with reference to FIGs. 4 through 7. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1005, the UE may establish a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation. The operations of 1005 may be performed according to the methods described herein. In some examples, aspects of the operations of 1005 may be performed by a cell connection manager as described with reference to FIGs. 4 through 7.

At 1010, the UE may determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both. The operations of 1010 may be performed according to the methods described herein. In some examples, aspects of the operations of 1010 may be performed by a signal parameter manager as described with reference to FIGs. 4 through 7.

At 1015, the UE may determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both. The operations of 1015 may be performed according to the methods described herein. In some examples, aspects of the operations of 1015 may be performed by a cell selection parameter manager as described with reference to FIGs. 4 through 7.

At 1020, the UE may determine that the reference signal parameter does not satisfy the reference signal threshold, or that the received signal parameter does not satisfy the received signal threshold, or both. The operations of 1020 may be performed according to the methods described herein. In some examples, aspects of the operations of 1020 may be performed by a signal parameter manager as described with reference to FIGs. 4 through 7.

At 1025, the UE may maintain the connection with the first cell based on determining that the reference signal parameter does not satisfy the reference signal threshold, or that the received signal parameter does not satisfy the received signal threshold, or both. The operations of 1025 may be performed according to the methods described herein. In some examples, aspects of the operations of 1025 may be performed by a cell connection manager as described with reference to FIGs. 4 through 7.

At 1030, the UE may establish a connection with a second cell associated with a second radio access technology based on determining that the cell selection criterion satisfies the cell selection criterion threshold. The operations of 1030 may be performed according to the methods described herein. In some examples, aspects of the operations of 1030 may be performed by a cell connection manager as described with reference to FIGs. 4 through 7.

FIG. 11 shows a flowchart illustrating a method 1100 that supports improving cell selection over new radio in accordance with aspects of the present disclosure. The operations of method 1100 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1100 may be performed by a communications manager as described with reference to FIGs. 4 through 7. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1105, the UE may establish a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation. The operations of 1105 may be performed according to the methods described herein. In some examples, aspects of the operations of 1105 may be performed by a cell connection manager as described with reference to FIGs. 4 through 7.

At 1110, the UE may determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both. The operations of 1110 may be performed according to the methods described herein. In some examples, aspects of the operations of 1110 may be performed by a signal parameter manager as described with reference to FIGs. 4 through 7.

At 1115, the UE may determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both. The operations of 1115 may be performed according to the methods described herein. In some examples, aspects of the operations of 1115 may be performed by a cell selection parameter manager as described with reference to FIGs. 4 through 7.

At 1120, the UE may determine that the cell selection criterion does not satisfy the cell selection criterion threshold based on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both. The operations of 1120 may be performed according to the methods described herein. In some examples, aspects of the operations of 1120 may be performed by a cell selection parameter manager as described with reference to FIGs. 4 through 7.

At 1125, the UE may maintain the connection with the first cell based on determining the cell selection criterion does not satisfy the cell selection criterion threshold. The operations of 1125 may be performed according to the methods described herein. In some examples, aspects of the operations of 1125 may be performed by a cell connection manager as described with reference to FIGs. 4 through 7.

At 1130, the UE may establish a connection with a second cell associated with a second radio access technology based on determining that the cell selection criterion satisfies the cell selection criterion threshold. The operations of 1130 may be performed according to the methods described herein. In some examples, aspects of the operations of 1130 may be performed by a cell connection manager as described with reference to FIGs. 4 through 7.

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

Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to various other wireless communications systems such as Ultra Mobile Broadband (UMB) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein.

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

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. ”

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A method for wireless communication at a user equipment (UE) , comprising:

establishing a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation;

determining that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both;

determining that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based at least in part on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both; and

establishing a connection with a second cell associated with a second radio access technology based at least in part on determining that the cell selection criterion satisfies the cell selection criterion threshold.
The method of claim 1, further comprising:

determining that a radio access technology timer has expired; and

transmitting, to a base station supporting the first cell, an attach request message for a second connection with the first cell based at least in part on determining that the radio access technology timer has expired.
The method of claim 2, further comprising:

receiving, from the base station supporting the first cell, an attach accept message, wherein the attach accept message is received based at least in part on the attach request message; and

establishing the second connection with the first cell associated with the first radio access technology based at least in part on the attach accept message.
The method of claim 2, further comprising:

initiating the radio access technology timer based at least in part on establishing the connection with the second cell associated with the second radio access technology; and

determining that the radio access technology timer has expired based at least in part on initiating the radio access technology timer and a timer duration.
The method of claim 1, further comprising:

detaching from the first cell based at least in part on establishing the connection with the second cell.
The method of claim 1, further comprising:

receiving, from a base station supporting the first cell, a system information broadcast message including an indication of the cell selection criterion threshold, wherein determining that the cell selection criterion satisfies the cell selection criterion threshold is based at least in part on receiving the system information broadcast message.
The method of claim 1, further comprising:

receiving, from a base station supporting the first cell, at least one of a system information broadcast message, a radio resource control message, a synchronization signal block message, a configuration message, or downlink control information including an indication of at least one of the reference signal threshold or the received signal threshold, wherein determining that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter satisfies the received signal threshold, or both, is based at least in part on receiving the at least one of the system information broadcast message, the radio resource control message, the synchronization signal block message, the configuration message, or the downlink control information including the indication.
The method of claim 1, further comprising:

determining that a second cell selection criterion associated with the second cell satisfies a second cell selection criterion threshold based at least in part on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both; and

wherein establishing the connection with the second cell is based at least in part on the second cell selection criterion associated with the second cell satisfying the second cell selection criterion threshold.
The method of claim 8, wherein the second cell selection criterion associated with the second cell satisfies the second cell selection criterion threshold when the second cell selection criterion is greater than the second cell selection criterion threshold.
The method of claim 1, further comprising:

determining that the reference signal parameter does not satisfy the reference signal threshold, or that the received signal parameter does not satisfy the received signal threshold, or both; and

maintaining the connection with the first cell based at least in part on determining that the reference signal parameter does not satisfy the reference signal threshold, or that the received signal parameter does not satisfy the received signal threshold, or both.
The method of claim 1, further comprising:

determining that the cell selection criterion does not satisfy the cell selection criterion threshold based at least in part on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both; and

maintaining the connection with the first cell based at least in part on determining the cell selection criterion does not satisfy the cell selection criterion threshold.
The method of claim 1, wherein:

the reference signal parameter satisfies the reference signal threshold when the reference signal parameter is less than the reference signal threshold;

the received signal parameter satisfies the received signal threshold when the received signal parameter is less than the received signal threshold; and

the cell selection criterion satisfies the cell selection criterion threshold when the cell selection criterion is less than the cell selection criterion threshold.
The method of claim 1, wherein determining that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter satisfies the received signal threshold, or both comprises:

determining that the reference signal parameter satisfies the reference signal threshold; and

determining that the received signal parameter satisfies the received signal threshold.
The method of claim 13, wherein:

determining that the cell selection criterion satisfies the cell selection criterion threshold is based at least in part on determining that the reference signal parameter satisfies the reference signal threshold and determining that the received signal parameter satisfies the received signal threshold.
The method of claim 1, wherein the reference signal parameter comprises a reference signal received power value, a reference signal received quality value, or both.
The method of claim 1, wherein the received signal parameter comprises a signal-to-noise ratio, a signal-to-interference-plus noise ratio, or both.
The method of claim 1, wherein the cell selection criterion is based at least in part on the reference signal parameter, a minimum reference signal received power value, a reference signal received quality value, a minimum reference signal received quality value, or any combination thereof.
The method of claim 1, further comprising:

receiving an input via the UE, wherein determining that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter associated with the first cell satisfies the received signal threshold, or both, is based at least in part on receiving the input.
The method of claim 1, further comprising:

performing a setup procedure for a third cell associated with a third radio access technology based at least in part on establishing the connection with the first cell while in the dual connectivity mode of operation.
The method of claim 19, wherein the third radio access technology comprises a new radio technology, a fifth generation (5G) technology, or both.
The method of claim 19, further comprising:

detaching from the third cell based at least in part on establishing the connection with the second cell.
The method of claim 1, wherein:

the first radio access technology comprises a long term evolution technology, a fourth generation (4G) technology, or both; and

the second radio access technology comprises a third generation (3G) technology.
An apparatus for wireless communication at a user equipment (UE) , comprising:

a processor,

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

establish a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation;

determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both;

determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based at least in part on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both; and

establish a connection with a second cell associated with a second radio access technology based at least in part on determining that the cell selection criterion satisfies the cell selection criterion threshold.
The apparatus of claim 23, wherein the instructions are further executable by the processor to cause the apparatus to:

determine that a radio access technology timer has expired; and

transmit, to a base station supporting the first cell, an attach request message for a second connection with the first cell based at least in part on determining that the radio access technology timer has expired.
The apparatus of claim 24, wherein the instructions are further executable by the processor to cause the apparatus to:

receive, from the base station supporting the first cell, an attach accept message, wherein the attach accept message is received based at least in part on the attach request message; and

establish the second connection with the first cell associated with the first radio access technology based at least in part on the attach accept message.
The apparatus of claim 24, wherein the instructions are further executable by the processor to cause the apparatus to:

initiate the radio access technology timer based at least in part on establishing the connection with the second cell associated with the second radio access technology; and

determine that the radio access technology timer has expired based at least in part on initiating the radio access technology timer and a timer duration.
The apparatus of claim 23, wherein the instructions are further executable by the processor to cause the apparatus to:

detach from the first cell based at least in part on establishing the connection with the second cell.
The apparatus of claim 23, wherein the instructions are further executable by the processor to cause the apparatus to:

receive, from a base station supporting the first cell, a system information broadcast message including an indication of the cell selection criterion threshold, wherein determining that the cell selection criterion satisfies the cell selection criterion threshold is based at least in part on receiving the system information broadcast message.
The apparatus of claim 23, wherein the instructions are further executable by the processor to cause the apparatus to:

receive, from a base station supporting the first cell, at least one of a system information broadcast message, a radio resource control message, a synchronization signal block message, a configuration message, or downlink control information including an indication of at least one of the reference signal threshold or the received signal threshold, wherein determining that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter satisfies the received signal threshold, or both, is based at least in part on receiving the at least one of the system information broadcast message, the radio resource control message, the synchronization signal block message, the configuration message, or the downlink control information including the indication.
The apparatus of claim 23, wherein the instructions are further executable by the processor to cause the apparatus to:

determine that a second cell selection criterion associated with the second cell satisfies a second cell selection criterion threshold based at least in part on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both; and

wherein establishing the connection with the second cell is based at least in part on the second cell selection criterion associated with the second cell satisfying the second cell selection criterion threshold.
The apparatus of claim 30, wherein the second cell selection criterion associated with the second cell satisfies the second cell selection criterion threshold when the second cell selection criterion is greater than the second cell selection criterion threshold.
The apparatus of claim 23, wherein the instructions are further executable by the processor to cause the apparatus to:

determine that the reference signal parameter does not satisfy the reference signal threshold, or that the received signal parameter does not satisfy the received signal threshold, or both; and

maintain the connection with the first cell based at least in part on determining that the reference signal parameter does not satisfy the reference signal threshold, or that the received signal parameter does not satisfy the received signal threshold, or both.
The apparatus of claim 23, wherein the instructions are further executable by the processor to cause the apparatus to:

determine that the cell selection criterion does not satisfy the cell selection criterion threshold based at least in part on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both; and

maintain the connection with the first cell based at least in part on determining the cell selection criterion does not satisfy the cell selection criterion threshold.
The apparatus of claim 23, wherein:

the reference signal parameter satisfies the reference signal threshold when the reference signal parameter is less than the reference signal threshold;

the received signal parameter satisfies the received signal threshold when the received signal parameter is less than the received signal threshold; and

the cell selection criterion satisfies the cell selection criterion threshold when the cell selection criterion is less than the cell selection criterion threshold.
The apparatus of claim 23, wherein the instructions to determine that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter satisfies the received signal threshold, or both are executable by the processor to cause the apparatus to:

determine that the reference signal parameter satisfies the reference signal threshold; and

determine that the received signal parameter satisfies the received signal threshold.
The apparatus of claim 35, wherein determining that the cell selection criterion satisfies the cell selection criterion threshold is based at least in part on determining that the reference signal parameter satisfies the reference signal threshold and determining that the received signal parameter satisfies the received signal threshold.
The apparatus of claim 23, wherein the reference signal parameter comprises a reference signal received power value, a reference signal received quality value, or both.
The apparatus of claim 23, wherein the received signal parameter comprises a signal-to-noise ratio, a signal-to-interference-plus noise ratio, or both.
The apparatus of claim 23, wherein the cell selection criterion is based at least in part on the reference signal parameter, a minimum reference signal received power value, a reference signal received quality value, a minimum reference signal received quality value, or any combination thereof.
The apparatus of claim 23, wherein the instructions are further executable by the processor to cause the apparatus to:

receive an input via the UE, wherein determining that the reference signal parameter satisfies the reference signal threshold, or that the received signal parameter associated with the first cell satisfies the received signal threshold, or both, is based at least in part on receiving the input.
The apparatus of claim 23, wherein the instructions are further executable by the processor to cause the apparatus to:

perform a setup procedure for a third cell associated with a third radio access technology based at least in part on establishing the connection with the first cell while in the dual connectivity mode of operation.
The apparatus of claim 41, wherein the third radio access technology comprises a new radio technology, a fifth generation (5G) technology, or both.
The apparatus of claim 41, wherein the instructions are further executable by the processor to cause the apparatus to:

detach from the third cell based at least in part on establishing the connection with the second cell.
The apparatus of claim 23, wherein:

the first radio access technology comprises a long term evolution technology, a fourth generation (4G) technology, or both; and

the second radio access technology comprises a third generation (3G) technology.
An apparatus for wireless communication at a user equipment (UE) , comprising:

means for establishing a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation;

means for determining that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both;

means for determining that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based at least in part on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both; and

means for establishing a connection with a second cell associated with a second radio access technology based at least in part on determining that the cell selection criterion satisfies the cell selection criterion threshold.
A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE) , the code comprising instructions executable by a processor to:

establish a connection with a first cell associated with a first radio access technology while in a dual connectivity mode of operation;

determine that a reference signal parameter associated with the first cell satisfies a reference signal threshold, or that a received signal parameter associated with the first cell satisfies a received signal threshold, or both;

determine that a cell selection criterion associated with the first cell satisfies a cell selection criterion threshold based at least in part on the reference signal parameter satisfying the reference signal threshold, or the received signal parameter satisfying the received signal threshold, or both; and

establish a connection with a second cell associated with a second radio access technology based at least in part on determining that the cell selection criterion satisfies the cell selection criterion threshold.