WO2021253279A1

WO2021253279A1 - Preventing frequent 5g new radio (nr) cell handovers in a non-standalone (nsa) mode when user equipment (ue) is stationary

Info

Publication number: WO2021253279A1
Application number: PCT/CN2020/096553
Authority: WO
Inventors: Haojun WANG; Yi Liu; Jinglin Zhang; Zhenqing CUI; Hong Wei
Original assignee: Qualcomm Incorporated
Priority date: 2020-06-17
Filing date: 2020-06-17
Publication date: 2021-12-23

Abstract

This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer- readable media, for preventing frequent 5GNew Radio (NR) cell handovers when a user equipment (UE) is stationary and is operating in a non- standalone (NSA) Evolved Universal Terrestrial Radio Access (E-UTRA) NR Dual Connectivity (EN-DC) mode. In some aspects, the UE may determine a first signal quality measurement for a 5G serving cell and a second signal quality measurement for a 5G neighbor cell. The UE may determine whether the UE, remained stationary for a time period based on sensor information. If the UE remained stationary, the UE, may modify the first signal quality measurement with a static bias offset. The UE may determining whether to output a handover measurement report, for transmission to the 5G serving cell based on the modified first signal quality measurement and the second signal quality measurement.

Description

PREVENTING FREQUENT 5G NEW RADIO (NR) CELL HANDOVERS IN A NON-STANDALONE (NSA) MODE WHEN USER EQUIPMENT (UE) IS STATIONARY

TECHNICAL FIELD

Aspects of the present disclosure relate generally to wireless communication and to techniques for preventing frequent 5G New Radio (NR) cell handovers in a non-standalone (NSA) mode when the user equipment (UE) is stationary.

DESCRIPTION OF THE RELATED TECHNOLOGY

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 (such as time, frequency, and power) . A wireless multiple-access communications system may include a number of base stations (BSs) , each simultaneously supporting communications for multiple communication devices, which may be otherwise known as user equipment (UE) .

To meet the growing demands for expanded mobile broadband connectivity, wireless communication technologies are advancing from the 3 ^rd generation (3G) and 4 ^th generation (4G, including long term evolution (LTE) ) technologies to a next generation new radio (NR) technology, which may be referred to as 5 ^th Generation (5G) or 5G NR. For example, NR is designed to provide a lower latency, a higher bandwidth or a higher throughput, and a higher reliability than 3G or LTE. NR is designed to operate over a wide array of spectrum bands, for example, from low-frequency bands below about 1 gigahertz (GHz) and mid-frequency bands from about 1 GHz to about 6 GHz, to high-frequency bands such as millimeter wave (mmWave (mmW) ) bands. NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed and shared spectrum. Spectrum sharing enables operators to opportunistically aggregate spectrums to dynamically support high-bandwidth services. Spectrum sharing can extend the benefit of NR technologies to operating entities that may not have access to a licensed spectrum.

Wireless communication networks may support some combination of 2G, 3G, LTE, and 5G NR technologies. A UE may communicate with the wireless communication network using one or more of the 2G, 3G, LTE, and 5G NR technologies. For example, the UE may use 5G NR for some applications, such as data transmissions, and may use LTE for other applications, such as voice transmissions. A UE also may have access to wireless local area networks (WLANs) in the wireless communication network.

SUMMARY

The systems, methods, and devices of this disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

One innovative aspect of the subject matter described in this disclosure can be implemented in a method for wireless communication performed by an apparatus of a user equipment (UE) . The method may include determining, while the UE is connected with a serving cell associated with a 5G New Radio (NR) radio access technology (RAT) of a wireless wide area network (WWAN) , a first signal quality measurement from signals obtained from the serving cell and a second signal quality measurement from signals obtained from a neighbor cell associated with the 5G NR RAT. The method may include determining whether the UE remained stationary for a time period, and modifying the first signal quality measurement associated with the serving cell with a static bias offset in response to determining the UE remained stationary for the time period. The method may include determining whether to output a handover measurement report for transmission to the serving cell based on the modified first signal quality measurement associated with the serving cell and the second signal quality measurement associated with the neighbor cell.

In some implementations, the WWAN may include a 5G NR base station (BS) and a Long-Term Evolution (LTE) BS. The 5G NR BS may include the serving cell. The UE may be connected with both the LTE BS and the 5G NR BS. The LTE BS may be configured as a master node (MN) and the 5G NR BS may be configured as a secondary node (SN) .

In some implementations, the LTE BS and the 5G NR BS may have a non-standalone (NSA) architecture and may be configured to operate in an Evolved Universal Terrestrial Radio Access (E-UTRA) NR Dual Connectivity (EN-DC) mode.

In some implementations, the method may include determining whether the first signal quality measurement associated with the serving cell is greater than a static bias threshold, selecting a first offset of the static bias offset in response to determining the first signal quality measurement is greater than the static bias threshold, and modifying the first signal quality measurement with the first offset in response to determining the UE remained stationary for the time period.

In some implementations, the method may include selecting a second offset of the static bias offset in response to determining the first signal quality measurement is not greater than the static bias threshold, and modifying the first signal quality measurement with the second offset in response to determining the UE remained stationary for the time period.

In some implementations, the first offset may be greater than the second offset.

In some implementations, the WWAN may include a 5G NR BS. The 5G NR BS may include the serving cell and the neighbor cell.

In some implementations, the WWAN may include a first 5G NR BS and a second 5G NR BS. The first 5G NR BS may include the serving cell and the second 5G NR BS may include the neighbor cell.

In some implementations, the method for determining whether to output the handover measurement report for transmission to the serving cell may include determining whether a first handover condition associated with a first handover event is met based, at least in part, on a comparison of the modified first signal quality measurement and the second signal quality measurement, and determining whether to output the handover measurement report for transmission to the serving cell based, at least in part, on the comparison.

In some implementations, the first handover event may be an A3 event, and the first handover condition may be an A3 event condition.

In some implementations, the method for determining whether to output the handover measurement report for transmission to the serving cell may include determining whether a second handover condition associated with a second handover event is met based, at least in part, on a first comparison of the modified first signal quality measurement with a first signal quality threshold and a second comparison of the second signal quality measurement with a second signal quality threshold, and determining whether to output the handover measurement report for transmission to the serving cell based, at least in part, on the first comparison and the second comparison.

In some implementations, the second handover event may be an A5 event, and the second handover condition may be an A5 event condition.

In some implementations, the method of modifying the first signal quality measurement associated with the serving cell with the static bias offset may reduce a frequency of transmission of the handover measurement report.

In some implementations, the method of determining whether the UE remained stationary for the time period may include determining whether the UE remained stationary for the time period based on sensor information.

In some implementations, the method of determining whether the UE remained stationary for the time period may include determining whether an application processor of the UE provided a static mode indicator to a modem of the UE. The static mode indicator may indicate the UE remained stationary for the time period.

In some implementations, the first signal quality measurement and the second signal quality measurement may be reference signal received power (RSRP) measurements, reference signal received quality (RSRQ) measurements, or signal-to-interference-plus-noise ratio (SINR) measurements.

In some implementations, the time period may be between 5 and 300 seconds.

In some implementations, the time period may be a configurable time period.

Another innovative aspect of the subject matter described in this disclosure can be implemented by an apparatus of a UE for wireless communication including one or more interfaces for communicating via a WWAN. The apparatus of a UE may include one or more processors configured to determine, while the UE is connected with a serving cell associated with a 5G NR RAT of the WWAN, a first signal quality measurement from signals obtained from the serving cell and a second signal quality measurement from signals obtained from a neighbor cell associated with the 5G NR RAT, determine whether the UE remained stationary for a time period, modify the first signal quality measurement associated with the serving cell with a static bias offset in response to a determination that the UE remained stationary for the time period, and determine whether to output a handover measurement report via the one or more interfaces for transmission to the serving cell based on the modified first signal quality measurement associated with the serving cell and the second signal quality measurement associated with the neighbor cell.

In some implementations, the one or more processors are further configured to determine whether the first signal quality measurement associated with the serving cell is greater than a static bias threshold, select a first offset of the static bias offset in response to a determination that the first signal quality measurement is greater than the static bias threshold, and modify the first signal quality measurement with the first offset in response to a determination that the UE remained stationary for the time period.

In some implementations, the one or more processors are further configured to select a second offset of the static bias offset in response to a determination that the first signal quality measurement is not greater than the static bias threshold, and modify the first signal quality measurement with the second offset in response to a determination that the UE remained stationary for the time period.

In some implementations, the one or more processors are further configured to determine whether a first handover condition associated with a first handover event is met based, at least in part, on a comparison of the modified first signal quality measurement and the second signal quality measurement, and determine whether to output via the one or more interfaces the handover measurement report for transmission to the serving cell based, at least in part, on the comparison.

In some implementations, the one or more processors are further configured to determine whether a second handover condition associated with a second handover event is met based, at least in part, on a first comparison of the modified first signal quality measurement with a first signal quality threshold and a second comparison of the second signal quality measurement with a second signal quality threshold, and determine whether to output via the one or more interfaces the handover measurement report for transmission to the serving cell based, at least in part, on the first comparison and the second comparison.

In some implementations, the first signal quality measurement associated with the serving cell may be modified with the static bias offset to reduce a frequency of transmission of the handover measurement report.

In some implementations, the one or more processors are further configured to determine whether the UE remained stationary for the time period based on sensor information.

Another innovative aspect of the subject matter described in this disclosure can be implemented in a wireless communication device, such as a BS or a UE, which includes the above-mentioned apparatus that is configured to perform any of the above-mentioned methods.

Aspects of the subject matter described in this disclosure can be implemented in a device, a software program, a system, or other means to perform any of the above-mentioned methods.

Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings and the claims. Note that the relative dimensions of the following figures may not be drawn to scale.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a system diagram of an example wireless communication network.

Figure 2 is a block diagram conceptually illustrating an example of a base station (BS) in communication with a user equipment (UE) .

Figure 3 shows a system diagram of an example wireless communication system having a non-standalone (NSA) architecture that supports an Evolved Universal Terrestrial Radio Access (E-UTRA) New Radio (NR) Dual Connectivity (EN-DC) mode.

Figure 4 shows a system diagram of an example wireless communication system including a UE that is configured to prevent frequent 5G NR cell handovers in an NSA EN-DC mode when the UE is stationary.

Figure 5 depicts a flowchart with example operations performed by an apparatus of a UE for preventing frequent 5G NR cell handovers in an NSA EN-DC mode when the UE is stationary.

Figure 6 depicts a flowchart with example operations performed by an apparatus of a UE for preventing frequent 5G NR cell handovers in an NSA EN-DC mode when the UE is stationary.

Figure 7 shows a block diagram of an example wireless communication apparatus.

Figure 8 shows a block diagram of an example mobile communication device.

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

The following description is directed to certain implementations for the purposes of describing the innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. The examples in this disclosure are based on wireless network communications in wide area networks (WANs) . However, the described implementations may be implemented in any device, system or network that is capable of transmitting and receiving radio frequency signals according to any of the wireless communication standards, including any of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, the

standard, code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal FDMA (OFDMA) , single-carrier FDMA (SC-FDMA) , Global System for Mobile communications (GSM) , GSM/General Packet Radio Service (GPRS) , Enhanced Data GSM Environment (EDGE) , Terrestrial Trunked Radio (TETRA) , Wideband-CDMA (W-CDMA) , Evolution Data Optimized (EV-DO) , 1xEV-DO, EV-DO Rev A, EV-DO Rev B, High Speed Packet Access (HSPA) , High Speed Downlink Packet Access (HSDPA) , High Speed Uplink Packet Access (HSUPA) , Evolved High Speed Packet Access (HSPA+) , Long Term Evolution (LTE) , 5 ^th Generation (5G) or new radio (NR) , Advanced Mobile Phone Service (AMPS) , or other known signals that are used to communicate within a wireless, cellular or internet of things (IoT) network, such as a system utilizing 3G, 4G or 5G, or further implementations thereof, technology.

A wireless communication network (which also may be referred to as a wireless WAN or WWAN) may include a 5G NR radio access technology (RAT) of a 5G NR network and an LTE RAT of an LTE network. The wireless communication network also may include a legacy RAT of a legacy network, such as a 3G RAT of a 3G network or a 2G RAT of a 2G network. The RATs of a WWAN also may be referred to as WWAN RATs. A user equipment (UE) of the wireless communication network may use the 5G NR RAT, the LTE RAT, or a legacy RAT depending on which wireless coverage is available to the UE and which wireless coverage provides the best quality service.

An LTE base station (BS) that implements an LTE RAT and a 5G NR BS that implements a 5G NR RAT may have a non-standalone (NSA) architecture and may be configured to operate in an Evolved Universal Terrestrial Radio Access (E-UTRA) NR Dual Connectivity (EN-DC) mode. The EN-DC mode also may be referred to as an NSA EN-DC mode or an NSA mode. While operating in the EN-DC mode, the LTE BS may be configured to operate as a master node (MN) and the 5G NR BS may be configured to operate as a secondary node (SN) . When the UE operates in the EN-DC mode, the UE may establish both an LTE connection with the LTE BS and a 5G NR connection with the 5G NR BS. For initial deployments of 5G NR, various operators support the NSA EN-DC mode for 5G commercialization based on the relatively low cost of deployment and a relatively fast time to market.

When the UE is connected to a 5G serving cell of the 5G NR BS, the UE may perform signal quality measurements on signals received from the 5G serving cell of the BS and on signals received from one or more 5G neighbor cells to determine whether or not to transmit a handover measurement report to the 5G NR BS. The signal quality measurements may be reference signal received power (RSRP) measurements, reference signal received quality (RSRQ) measurements, or signal-to-interference-plus-noise ratio (SINR) measurements. The UE may determine whether or not to transmit a handover measurement report based on whether a handover condition associated a handover event is satisfied. For example, the UE may determine whether an A3 event condition associated with an A3 event is satisfied based on a comparison of a signal quality measurement associated with the 5G serving cell and a signal quality measurement associated with a 5G neighbor cell. The A3 event condition may be satisfied when the signal quality measurement associated with the 5G neighbor cell is greater than the signal quality measurement associated with the 5G serving cell by an offset. In the deployments of the NSA architecture that supports the NSA EN-DC mode, the operators typically configure the A3 event condition to have relatively small offset and hysteresis values. For example, when the offset is set to 2 decibels (dB) , the A3 event condition may be satisfied, and thus a handover measurement report may be triggered, when the signal quality measurement of the 5G neighbor cell is greater than the signal quality measurement of the 5G serving cell by the 2 dB offset. This relatively small offset may trigger frequent handovers (which may be referred to as “ping-pong” handovers) between the 5G NR cells when operating in the NSA EN-DC mode and when the UE is stationary. Frequent handovers may interrupt UE data transfers, which may reduce performance and thus impact user experience.

In some implementations, while operating in an EN-DC mode, the UE may determine whether the UE is stationary. For example, the UE may obtain sensor information from one or more sensors (such as an accelerometer) to determine whether the UE is stationary or in motion. If the UE is stationary, the UE may determine whether the UE remains stationary for a time period. If the UE determines that the UE remained stationary for the time period, a static mode indicator may be enabled to indicate the UE remained stationary for the time period.

In some implementations, when the static mode indicator is enabled (indicating the UE remained stationary for the time period) , the UE may determine to modify a signal quality measurement associated with the 5G serving cell with a static bias offset. The static bias offset may increase or improve the signal quality measurement associated with the 5G serving cell in order to prevent frequent 5G NR cell handovers when the UE has remained stationary for the time period. For example, the static bias offset may increase or improve the signal quality measurement such that the handover condition is satisfied less frequently and thus the handover measurement report is triggered less frequently, as further described herein.

In some implementations, the static bias offset may be selected based on a comparison of the signal quality measurement associated with the 5G serving cell to a static bias threshold. If the signal quality measurement is greater than the static bias threshold, the UE may select a first offset for the static bias offset and may use the first offset to modify the signal quality measurement. If the signal quality measurement is less than or equal to the static bias threshold, the UE may select a second offset for the static bias offset and may use the second offset to modify the signal quality measurement. In some implementations, the first offset may be greater than the second offset.

In some implementations, after modifying the signal quality measurement with the static bias offset, the UE may determine whether a handover condition for a handover event is satisfied based on a comparison of the modified signal quality measurement associated with the 5G serving cell and the signal quality measurement associated with the 5G neighbor cell. The handover condition for the handover event may be an A3 event condition for an A3 event or an A5 event condition for an A5 event. The A3 and A5 events are measurement reporting events described in Section 5.5.4 of the 3GPP technical specification (TS) 38.331, version 15.8.0 (2019-12) (hereafter “TS 38.331” ) . The UE may determine to prepare and transmit a handover measurement report when either the A3 event condition for the A3 event is met or the A5 event condition for the A5 event is met, as described further herein.

Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. By modifying the signal quality measurement associated with the 5G serving cell with the static bias offset, one or more handover condition associated with one or more handover events may be satisfied less frequently and thus the UE may transmit a handover measurement report less frequently to the 5G NR BS. Transmitting a handover measurement report less frequently to the 5G NR BS may result in the 5G NR BS initiating fewer 5G NR cell handovers for the UE when the UE has remained stationary for the time period. Initiating fewer 5G NR cell handovers for the UE when the UE is stationary may prevent frequent 5G NR cell handovers when the UE is operating in an NSA EN-DC mode. Preventing frequent 5G NR cell handovers may improve power consumption and prevent data transfer interruptions, which may improve UE performance and improve the user experience. Preventing frequent 5G NR cell handovers also may reduce network traffic and improve the 5G NR BS’s mobility management.

Figure 1 is a system diagram of an example wireless communication network 100. The wireless communication network 100 may be an LTE network or a 5G NR network, or a combination thereof. The wireless communication network 100 also may be referred to as a wide area network (WAN) or a wireless wide area network (WWAN) . The wireless communication network 100 includes a number of base stations (BSs) 110 (individually labeled as 110A, 110B, 110C, 110D, 110E, and 110F) and other network entities. A BS 110 may be a station that communicates with UEs 120 and also may be referred to as an evolved node B (eNB) , a next generation eNB (gNB) , an access point, and the like. In some implementations, a BS 110 may represent an eNB of an LTE network or a gNB of a 5G NR network, or a combination thereof. Each BS 110 may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to this particular geographic coverage area of a BS 110 or a BS subsystem serving the coverage area, depending on the context in which the term is used.

A BS 110 may provide communication coverage for a macro cell or a small cell, such as a pico cell or a femto cell, or other types of cells. A macro cell generally covers a relatively large geographic area (such as several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A pico cell generally covers a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A femto cell generally covers a relatively small geographic area (such as a home) and, in addition to unrestricted access, also may provide restricted access by UEs having an association with the femto cell (such as UEs in a closed subscriber group (CSG) , UEs for users in the home, and the like) . A BS for a macro cell may be referred to as a macro BS. A BS for a small cell may be referred to as a small cell BS, a pico BS, a femto BS or a home BS. In the example shown in Figure 1, the

BSs

110D and 110E may be regular macro BSs, while the BSs 110A-110C may be macro BSs enabled with three dimensions (3D) , full dimensions (FD) , or massive MIMO. The BSs 110A-110C may take advantage of their higher dimension MIMO capabilities to exploit 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. The BS 110F may be a small cell BS which may be a home node or portable access point. A BS 110 may support one or multiple (such as two, three, four, and the like) cells.

The wireless communication network 100 may support synchronous or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time.

The UEs 120 are dispersed throughout the wireless communication network 100, and each UE 120 may be stationary or mobile. A UE 120 also may be referred to as a terminal, a mobile station, a wireless device, a subscriber unit, a station, or the like. A UE 120 may be a mobile phone, a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a wearable device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a smart appliance, a drone, a video camera, a sensor, or the like. In one aspect, a UE 120 may be a device that includes a Universal Integrated Circuit Card (UICC) . In another aspect, a UE may be a device that does not include a UICC. In some aspects, the UEs 120 that do not include UICCs also may be referred to as IoT devices or internet of everything (IoE) devices. The UEs 120A-120D are examples of mobile smart phone-type devices that may access the wireless communication network 100. A UE 120 also may be a machine specifically configured for connected communication, including machine type communication (MTC) , enhanced MTC (eMTC) , narrowband IoT (NB-IoT) , and the like. The UEs 120E-120L are examples of various machines configured for communication that access the wireless communication network 100. A UE 120 may be able to communicate with any type of the BSs, whether macro BS, small cell, or the like. In Figure 1, a lightning bolt is representative of a communication link that indicates wireless transmissions between a UE 120 and a serving BS 110, which is a BS designated to serve the UE 120 on the downlink and uplink, or desired transmission between BSs, and backhaul transmissions between BSs.

In operation, the BSs 110A-110C may serve the

UEs

120A and 120B using 3D beamforming and coordinated spatial techniques, such as coordinated multipoint (CoMP) or multi-connectivity. The macro BS 110D may perform backhaul communications with the BSs 110A-110C, as well as the BS 110F (which may be a small cell BS) . The macro BS 110D also may transmit multicast services which are subscribed to and received by the UEs 120C and 120D. Such multicast services may include mobile television or stream video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or gray alerts.

The BSs 110 also may communicate with a core network. The core network may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of the BSs 110 (such as a gNB or an access node controller (ANC) ) may interface with the core network through backhaul links (such as NG-C and NG-U) and may perform radio configuration and scheduling for communication with the UEs 120. In various examples, the BSs 110 may communicate, either directly or indirectly (such as through core network) , with each other over backhaul links, which may be wired or wireless communication links.

The wireless communication network 100 also may support mission critical communications with ultra-reliable and redundant links for mission critical devices, such as the UE 120E, which may be a drone. Redundant communication links with the UE 120E may include links from the

macro BSs

110D and 110E, as well as links from the small cell BS 110F. Other machine type devices, such as the UE 120F and UE 120G (such as video cameras or smart lighting) , the UE 120H (such as a smart meter) , and UE 120I (such as a wearable device) may communicate through the wireless communication network 100 either directly with the BSs, such as the small cell BS 110F, and the macro BS 110E, or in multi-hop configurations by communicating with another user device which relays its information to the wireless communication network 100. For example, the UE 120H may communicate smart meter information to the UE 120I (such as a wearable device or mobile phone) , which may report to the wireless communication network 100 through the small cell BS 110F. The wireless communication network 100 also may provide additional network efficiency through dynamic, low-latency TDD/FDD communications, such as in vehicle-to-vehicle (V2V) communications, as shown by UEs 120J-120L. Furthermore, the wireless communication network 100 may include one or more access points (APs) 107 that are part of one or more wireless local area networks (WLANs) . The APs 107 (which also may be referred to as WLAN APs) may provide short-range wireless connectivity to the UEs 120 of the wireless communication network 100.

In some implementations, the wireless communication network 100 may utilize OFDM-based waveforms for communications. An OFDM-based system may partition the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, bins, or the like. Each subcarrier may be modulated with data. In some instances, the subcarrier spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system BW. The system BW also may be partitioned into subbands. In other instances, the subcarrier spacing and/or the duration of TTIs may be scalable.

The BSs 110 may assign or schedule transmission resources (such as in the form of time-frequency resource blocks (RB) ) for downlink (DL) and uplink (UL) transmissions in the wireless communication network 100. DL refers to the transmission direction from a BS 110 to a UE 120, whereas UL refers to the transmission direction from a UE 120 to a BS 110. The communication can be in the form of radio frames. A radio frame may be divided into a plurality of subframes or slots. Each slot may be further divided into mini-slots. In a FDD mode, simultaneous UL and DL transmissions may occur in different frequency bands. For example, each subframe includes a UL subframe in a UL frequency band and a DL subframe in a DL frequency band. In a TDD mode, UL and DL transmissions occur at different time periods using the same frequency band. For example, a subset of the subframes (such as the DL subframes) in a radio frame may be used for DL transmissions, and another subset of the subframes (such as the UL subframes) in the radio frame may be used for UL transmissions.

The DL subframes and the UL subframes can be further divided into several regions. For example, each DL or UL subframe may have pre-defined regions for transmissions of reference signals, control information, and data. Reference signals are predetermined signals that facilitate the communications between the BSs 110 and the UEs 120. For example, a reference signal can have a particular pilot pattern or structure, where pilot tones may span across an operational BW or frequency band, each positioned at a pre-defined time and a pre-defined frequency. For example, a BS 110 may transmit cell-specific reference signals (CRSs) or channel state information reference signals (CSI-RSs) to enable a UE 120 to estimate a DL channel. Similarly, a UE 120 may transmit sounding reference signals (SRSs) to enable a BS 110 to estimate a UL channel. Control information may include resource assignments and protocol controls. Data may include protocol data and operational data. In some aspects, the BSs 110 and the UEs 120 may communicate using self-contained subframes. A self-contained subframe may include a portion for DL communication and a portion for UL communication. A self-contained subframe can be DL-centric or UL-centric. A DL-centric subframe may include a longer duration for DL communication than for UL communication. A UL-centric subframe may include a longer duration for UL communication than for UL communication.

In some aspects, the wireless communication network 100 may be an NR network deployed over a licensed spectrum or an NR network deployed over an unlicensed spectrum (such as NR-U and NR-U lite networks) . The BSs 110 can transmit synchronization signals, including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) , in the wireless communication network 100 to facilitate synchronization. The BSs 110 can broadcast system information associated with the wireless communication network 100 (such as a master information block (MIB) , remaining system information (RMSI) , and other system information (OSI) ) to facilitate initial network access. In some instances, the BSs 110 may broadcast one or more of the PSS, the SSS, and the MIB in the form of synchronization signal block (SSBs) over a physical broadcast channel (PBCH) and may broadcast one or more of the RMSI and the OSI over a physical downlink shared channel (PDSCH) .

In some aspects, a UE 120 attempting to access the wireless communication network 100 may perform an initial cell search by detecting a PSS included in an SSB from a BS 110. The PSS may enable synchronization of period timing and may indicate a physical layer identity value. The UE 120 may receive an SSS included in an SSB from the BS 110. The SSS may enable radio frame synchronization, and may provide a cell identity value, which may be combined with the physical layer identity value to identify the cell. The PSS and the SSS may be located in a central portion of a carrier or any suitable frequencies within the carrier.

After receiving the PSS and SSS, the UE 120 may receive an MIB. The MIB may include system information for initial network access and scheduling information for at least one of an RMSI and OSI. After decoding the MIB, the UE 120 may receive at least one of an RMSI and OSI. The RMSI and OSI may include radio resource control (RRC) information related to random access channel (RACH) procedures, paging, control resource set (CORESET) for physical downlink control channel (PDCCH) monitoring, physical uplink control channel (PUCCH) , physical uplink shared channel (PUSCH) , power control, and SRS.

After obtaining one or more of the MIB, the RMSI and the OSI, the UE 120 can perform a random access procedure to establish a connection with the BS 110. In some examples, the random access procedure may be a four-step random access procedure. For example, the UE 120 may transmit a physical random access channel (PRACH) , such as a PRACH preamble, and the BS 110 may respond with a random access response (RAR) . The RAR may include one or more of a detected random access preamble identifier (ID) corresponding to the PRACH preamble, timing advance (TA) information, a UL grant, a temporary cell-radio network temporary identifier (C-RNTI) , and a backoff indicator. Upon receiving the RAR, the UE 120 may transmit a connection request to the BS 110 and the BS 110 may respond with a connection response. The connection response may indicate a contention resolution. In some examples, the PRACH, the RAR, the connection request, and the connection response can be referred to as message 1 (MSG1) , message 2 (MSG2) , message 3 (MSG3) , and message 4 (MSG4) , respectively. In some examples, the random access procedure may be a two-step random access procedure, where the UE 120 may transmit a PRACH (including a PRACH preamble) and a connection request in a single transmission and the BS 110 may respond by transmitting a RAR and a connection response in a single transmission.

After establishing a connection, the UE 120 and the BS 110 can enter a normal operation stage, where operational data may be exchanged. For example, the BS 110 may schedule the UE 120 for UL and DL communications. The BS 110 may transmit UL and DL scheduling grants to the UE 120 via a PDCCH. The BS 110 may transmit a DL communication signal to the UE 120 via a PDSCH according to a DL scheduling grant. The UE 120 may transmit a UL communication signal to the BS 110 via a PUSCH or PUCCH according to a UL scheduling grant.

In some aspects, the wireless communication network 100 may operate over a system BW or a component carrier BW. The wireless communication network 100 may partition the system BW into multiple bandwidth parts (BWPs) . A BWP may be a certain portion of the system BW. For example, if the system BW is 100 MHz, the BWPs may each be 20 MHz or less. A BS 110 may dynamically assign a UE 120 to operate over a certain BWP. The assigned BWP may be referred to as the active BWP. The UE 120 may monitor the active BWP for signaling information from the BS 110. The BS 110 may schedule the UE 120 for UL or DL communications in the active BWP. In some implementations, the BS 110 may configure UEs 120 with narrowband operation capabilities (such as with transmission and reception limited to a BW of 20 MHz or less) to perform BWP hopping for channel monitoring and communications.

In some aspects, a BS 110 may assign a pair of BWPs within the component carrier to a UE 120 for UL and DL communications. For example, the BWP pair may include one BWP for UL communications and one BWP for DL communications. The BS 110 may additionally configure the UE 120 with one or more CORESETs in a BWP. A CORESET may include a set of frequency resources spanning a number of symbols in time. The BS 110 may configure the UE 120 with one or more search spaces for PDCCH monitoring based on the CORESETS. The UE 120 may perform blind decoding in the search spaces to search for DL control information (such as UL or DL scheduling grants) from the BS 110. For example, the BS 110 may configure the UE 120 with one or more of the BWPs, the CORESETS, and the PDCCH search spaces via RRC configurations.

In some aspects, the wireless communication network 100 may operate over a shared frequency band or an unlicensed frequency band, for example, at about 3.5 gigahertz (GHz) , sub-6 GHz or higher frequencies in the mmWave band. The wireless communication network 100 may partition a frequency band into multiple channels, for example, each occupying about 20 MHz. The BSs 110 and the UEs 120 may be operated by multiple network operating entities sharing resources in the shared communication medium and may employ a LBT procedure to acquire channel occupancy time (COT) in the share medium for communications. A COT may be non-continuous in time and may refer to an amount of time a wireless node can send frames when it has won contention for the wireless medium. Each COT may include a plurality of transmission slots. A COT also may be referred to as a transmission opportunity (TXOP) . The BS 110 or the UE 120 may perform an LBT in the frequency band prior to transmitting in the frequency band. The LBT can be based on energy detection or signal detection. For energy detection, the BS 110 or the UE 120 may determine that the channel is busy or occupied when a signal energy measured from the channel is greater than a certain signal energy threshold. For signal detection, the BS 110 or the UE 120 may determine that the channel is busy or occupied when a certain reservation signal (such as a preamble signal sequence) is detected in the channel.

Figure 2 is a block diagram conceptually illustrating an example 200 of a BS 110 in communication with a UE 120. In some aspects, BS 110 and UE 120 may respectively be one of the BSs and one of the UEs in wireless communication network 100 of Figure 1. BS 110 may be equipped with T antennas 234A through 234T, and UE 120 may be equipped with R antennas 252A through 252R, where in general T ≥ 1 and R ≥ 1.

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

At UE 120, antennas 252A through 252R may receive the downlink signals from BS 110 or other BSs and may provide received signals to modulators-demodulators (MODs-DEMODs) 254A through 254R, respectively (which also may be referred to as mods/demods or modems) . Each MOD-DEMOD 254 may condition (for example, filter, amplify, downconvert, and digitize) a received signal to obtain input samples. Each MOD-DEMOD 254 may further process the input samples (for example, for OFDM, etc. ) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R MODs-DEMODs 254A through 254R, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (for example, demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller or processor (controller/processor) 280. A channel processor may determine reference signal received power (RSRP) , received signal strength indicator (RSSI) , reference signal received quality (RSRQ) , channel quality indicator (CQI) , etc. In some aspects, one or more components of UE 120 may be included in a housing.

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

The controller/processor 240 of BS 110, the controller/processor 280 of UE 120, or any other component (s) of Figure 2 may perform one or more techniques associated with preventing frequent 5G NR cell handovers when the UE is stationary, as described in more detail elsewhere herein. For example, the controller/processor 240 of BS 110, the controller/processor 280 of UE 120, or any other component (s) (or combinations of components) of Figure 2 may perform or direct operations of, for example, the process depicted by flowchart 500 of Figure 5, the process depicted by flowchart 600 of Figure 6, or other processes as described herein, such as the processes described in Figure 4. The

memories

242 and 282 may store data and program codes for BS 110 and UE 120, respectively. A scheduler 246 may schedule UEs for data transmission on the downlink, the uplink, or a combination thereof.

The stored program codes, when executed by the controller/processor 280 or other processors and modules at UE 120, may cause the UE 120 to perform operations described with respect to the process depicted by flowchart 500 of Figure 5, the process depicted by flowchart 600 of Figure 6, or other processes as described herein, such as the processes described in Figure 4. The stored program codes, when executed by the controller/processor 240 or other processors and modules at BS 110, may cause the BS 110 to perform operations described with respect to the process depicted by flowchart 500 of Figure 5, the process depicted by flowchart 600 of Figure 6, or other processes as described herein, such as the processes described in Figure 4. A scheduler 246 may schedule UEs for data transmission on the downlink, the uplink, or a combination thereof.

In some aspects, UE 120 may include means for performing the process depicted by flowchart 500 of Figure 5, the process depicted by flowchart 600 of Figure 6, or other processes as described herein, such as the processes described in Figure 4. In some aspects, such means may include one or more components of UE 120 described in connection with Figure 2.

In some aspects, BS 110 may include means for performing the process depicted by flowchart 500 of Figure 5, the process depicted by flowchart 600 of Figure 6, or other processes as described herein, such as the processes described in Figure 4. In some aspects, such means may include one or more components of BS 110 described in connection with Figure 2.

While blocks in Figure 2 are illustrated as distinct components, the functions described above with respect to the blocks may be implemented in a single hardware, software, or combination component or in various combinations of components. For example, the functions described with respect to the transmit processor 264, the receive processor 258, the TX MIMO processor 266, or another processor may be performed by or under the control of controller/processor 280.

Figure 3 shows a system diagram of an example wireless communication system 300 having an NSA architecture that supports an EN-DC mode. The wireless communication system 300 may include a UE 120, an LTE radio access network (RAN) 320, a 5G NR RAN 360, an Evolved Packet Core (EPC) 330, and a packet network 340. The wireless communication system 300 may be part of a WWAN, such as the wireless communication network 100 of Figure 1. The UE 120 may include components (not shown) , such a communication unit (including a modem) and an application processor, among other examples, as shown in Figure 4. In some implementations, one or more chips or components of the UE 120 may include the communication unit and the application processor, and may communicate via one or more radio components of the UE 120. The communication unit may be capable of establishing an LTE connection (anchor connection) with a BS 111 (such as an eNB) of the LTE RAN 320 and establishing a 5G NR connection (secondary connection) with a BS 110 (such as a gNB) of the 5G NR RAN 360. For brevity, the description refers to the UE 120 making these connections. The UE 120 may refer to a portable electronic device or to one or more components of the portable electronic device.

The LTE RAN 320 may be an evolved universal terrestrial radio access network (E-UTRAN) and is just one example RAT that may be used for an access stratum of the wireless communication system 300. The EPC 330 is just one example of a core network that may be used in a non-access stratum of the wireless communication system 300. The 5G NR RAN 360 may use the same EPC 330 as the LTE RAN 320. Alternatively, the 5G NR RAN 360 may use a 5G Core (5GC) 370 with a 5G Core Access and Mobility Management Function (AMF) that performs similar functionality as the Mobility Management Entity (MME) 335 of the EPC 330. The 5GC 370 may connect to the packet network 340. In some deployments, the same packet network 340 may provide access to services such as Internet access, an IP multimedia subsystem (IMS) service, or other services. The example in Figure 3 is described with reference to an EN-DC configuration in which the LTE RAN 320 and the NR RAN 360 utilize the same EPC 330 of the wireless communication system 300.

Using EN-DC, the LTE RAN 320 and the 5G NR RAN 360 may be used to establish multiple wireless connections with the same UE 120. The UE 120 may establish a first wireless connection (such as the LTE connection 312) with the BS 111 of the LTE RAN 320. Establishing the first wireless connection may include the UE 120 sending an RRC Setup Request message to the BS 111 (such as an eNB) and receiving an RRC Setup message from the BS 111. Once the LTE connection 312 is connected, the UE may setup a default packet bearer to the EPC 330. For example, the UE 120 may send an attach request message to the MME 335 in the EPC 330. The MME 335 may respond with an attach accept message that sets up the default packet bearer. The default packet bearer may be used to communicate with the MME 335 or other elements in the EPC 330. The default packet bearer may be used to setup other bearers or services provided by the wireless communication system 300. For example, the UE may send packet data via the default packet bearer to a data packet gateway (P-GW) 345 in the EPC 330 that connects to the packet network 340.

In some implementations, the BS 110 and the BS 111 may have an NSA architecture and may be configured to operate in an EN-DC mode (which also may be referred to as an NSA EN-DC mode or an NSA mode) . After establishing the LTE connection 312, the UE 120 may establish a second wireless connection (such as the 5G NR connection 352) with the BS 110 (such as a gNB) of the 5G NR RAN 360. The second wireless connection may be established by the wireless communication system 300. For example, the BS 111 may determine that the UE 120 supports an EN-DC mode and may activate a bearer via the BS 110. The BS 111 may send an RRC Connection Reconfiguration message to the UE 120 to inform the UE 120 of the second wireless connection. Thereafter, the UE 120 may be in an EN-DC mode that includes wireless connections to both the BS 111 (such as an eNB) and the BS 110 (such as a gNB) . While operating in the EN-DC mode, the BS 111 may be referred to as a master node (MN) , and the BS 110 may be referred to as a secondary node (SN) .

Each BS (such as BS 110 and BS 111) may operate multiple cells. In some traditional deployments, a BS may operate three (3) cells, but other quantities of cells may be deployed at a BS. A master cell group (MCG) may include a primary cell (PCell) and zero or more secondary cells (SCells) of the BS 111. A secondary cell group (SCG) may include a primary SCG cell (PSCell) and zero or more secondary cells (SCells) of the BS 110. Once an SCG is added to the RRC configuration, the UE 120 may be in an NSA EN-DC mode of operation. Any of cells within the MCG or SCG may be referred to as a serving cell. For Dual Connectivity operation, the term Special Cell (SpCell) may be the serving cell and may refer to the PCell of the MCG or the PSCell of the SCG.

Once the UE 120 is in an RRC connected mode, the UE 120 may perform serving cell and neighbor cell measurements (which may be referred to as signal quality measurements) . The UE 120 may determine whether to generate and transmit a handover measurement report based on the serving cell and neighbor cell measurements, as described further in Figure 4. The premise of the handover measurement reports is for the UE 120 to inform the BS 110 or the BS 111 when a neighbor cell may provide a better service for the UE 120. In response, the BS 110 or the BS 111 may perform a handover from the serving cell to the neighbor cell. The handover may include some network-side reconfiguration, such as transferring bearers and changing a registration status of the UE 120, as well as UE-to-network reconfiguration, such as the BS 110 or the BS 111 sending an RRC Connection Reconfiguration message to the UE 120. The RRC Connection Reconfiguration message may include changes to the MCG or SCG as part of the handover.

Often, a UE 120 may be within overlapping coverage areas of different cells of a BS or of different BSs. When the signal strengths of a neighbor cell and a serving cell are similar (such as within 2–3 dB, or 1–5 dB, etc. ) , it is possible for the UE 120 to experience repetitive triggered handover measurement reports, which may result in an undesirable ping-pong situation with frequent handovers between two or more cells.

Figure 4 shows a system diagram of an example wireless communication system including a UE 120 that is configured to prevent frequent 5G NR cell handovers in an NSA EN-DC mode when the UE 120 is stationary. The wireless communication system 400 shown in Figure 4 may be based on the example wireless communication system 300 described in Figure 3. The wireless communication system 400 may be part of a WWAN, such as the wireless communication network 100 of Figure 1. The wireless communication system 400 may include the UE 120, a BS 110 of a 5G NR network, and a BS 111 of an LTE network. The UE 120 may be an example implementation of the UEs shown in Figures 1 and 2. The BS 110 and the BS 111 may each be an example implementation of the BSs shown in Figures 1 and 2. Although not shown for simplicity, the wireless communication system 400 may include one or more additional BSs and one or more additional UEs. In some implementations, the BS 110 may be a gNB that may implement a 5G NR RAT described in this disclosure to manage communications of a 5G NR network. In some implementations, the BS 111 may be an eNB that may implement an LTE RAT described in this disclosure to manage communications of an LTE network. In some implementations, the BS 110 and the BS 111 may have an NSA architecture and may be configured to operate in an EN-DC mode, as described with reference to Figure 3. The EN-DC mode also may be referred to as an NSA EN-DC mode or an NSA mode. While operating in the EN-DC mode, the BS 111 may be configured to operate as a MN and the BS 110 may be configured to operate as a SN, as described with reference to Figure 3. In some implementations, a gNB that is configured to operate in an EN-DC mode (such as the BS 110) may be referred to as an en-gNB.

In some implementations, the UE 120 may include a communication unit 422, an application processor 426, and sensors 428. The communication unit 422 may be configured to implement wireless communications using one or more WWAN RATs, such as an LTE RAT and a 5G NR RAT. The communication unit 422 may include a modem 423, a signal measurement unit 424, and a connection management unit 425. The modem 423 may be configured to process wireless communications received from the wireless communication system 400, and prepare wireless communications for transmission to the wireless communication system 400. In some implementations, the modem 423 may work in conjunction with the signal measurement unit 424 to perform signal quality measurements on received wireless signals. For example, the modem 423 may work in conjunction with the signal measurement unit 424 to perform signal quality measurements on 5G and LTE wireless signals (such as reference signals) received from the BS 110 and BS 111, respectively. The connection management unit 425 may be configured to perform operations to establish a wireless connection with a cell of a BS (such as the BS 110) of the wireless communication system 400. The connection management unit 425 may work in conjunction with the signal measurement unit 424 to generate handover measurement reports including signal quality measurements that may be used by the BS 110 and the BS 111 to make handover decisions. In some implementations, the connection management unit 425 may modify certain signal quality measurements (such as signal quality measurements derived from signals received from the BS 110) in order to prevent frequent 5G NR cell handovers when the UE 120 is stationary, as further described herein. The application processor 426 may be configured to execute one or more applications of the UE 120. The application processor 426 also may detect sensor information from the sensors 428 to determine whether the UE 120 is stationary or in motion. The sensors 428 may include one or more sensors that may provide sensor information that may indicate whether the UE 120 is stationary or in motion. For example, the one or more sensors may include an accelerometer, or a gyroscope. As another example, the one or more sensors may include a global positioning system (GPS) sensor. As another example, the one or more sensors may include both an accelerometer and a GPS sensor, etc.

In some implementations, the BS 110 may include a connection management unit 416. Although not shown for simplicity, the BS 111 also may include a connection management unit. The connection management unit 416 may perform operations to establish a wireless connection with one or more UEs of the wireless communication system 400 (such as the UE 120) , and may manage the wireless connections, such as to determine whether to maintain the wireless connections or whether to handoff one or more of the UEs to another BS.

In some implementations, while operating in an EN-DC mode, the UE 120 may establish a wireless connection (which may be referred to as a 5G NR connection 450) with the BS 110 to obtain 5G NR service, and may establish a wireless connection (which may be referred to as an LTE connection 455) with a BS 111 to obtain LTE service. In some implementations, the UE 120 may establish the 5G NR connection 450 with one of the cells of the BS 110 (which may be referred to as a 5G serving cell) , and may establish the LTE connection 455 with one of the cells of the BS 111 (which may be referred to as an LTE serving cell) .

In some implementations, while operating in an EN-DC mode, the UE 120 may perform signal quality measurements on signals received from the 5G serving cell of the BS 110 and on signals received from one or more neighbor cells (which may be referred to as 5G neighbor cells) to determine whether or not to transmit a handover measurement report to the BS 110. The one or more 5G neighbor cells may be one or more additional cells of the BS 110, or may be one or more cells of a different BS of the WWAN. If the UE 120 determines to generate and transmit a handover measurement report, the BS 110 may use the signal quality measurements included in the handover measurement report to initiate a handover of the UE 120 from the 5G serving cell to one of the 5G neighbor cells. If the UE 120 does not generate and transmit a handover measurement report, the UE 120 may continue to perform signal quality measurements and the UE 120 may remain connected to the 5G serving cell. In some implementations, the signal quality measurements may be reference signal received power (RSRP) measurements, reference signal received quality (RSRQ) measurements, or signal-to-interference-plus-noise ratio (SINR) measurements.

In some implementations, while operating in an EN-DC mode, the UE 120 also may determine whether the UE 120 is stationary. For example, the UE 120 may obtain sensor information from the sensors 428 (such as an accelerometer) and may determine whether the UE 120 is stationary or in motion based on the sensor information. The sensor information obtained from an accelerometer may be referred to as accelerometer sensor information. If the UE 120 is stationary, the UE 120 may determine whether the UE 120 remains stationary for a time period. For example, the UE 120 may implement a timer that may be used to monitor or track the time period. The UE 120 may initiate the timer when the UE 120 determines the UE 120 is stationary. In some implementations, the UE 120 may determine the UE 120 remained stationary for the time period if the time period expires without the UE 120 detecting motion. For example, the UE 120 may continue to monitor the sensor information to determine whether the UE 120 remains stationary during the time period or whether the UE 120 is moved or begins moving during the time period. If the UE 120 detects motion during the time period, the UE 120 may stop the timer and may continue monitoring the sensor information to detect when the UE 120 stops moving and is stationary. In some implementations, the time period may be preconfigured and may be configurable. As one non-limiting example, the time period may be set to 150 seconds. As another non-limiting example, the time period may be set to between 5 seconds and 300 seconds.

In some implementations, if the UE 120 determines that the UE 120 remained stationary for the time period, the application processor 426 may provide an indication to the communication unit 422 that indicates the UE 120 remained stationary for the time period. For example, the application processor 426 may provide a static mode indicator (which also may be referred to as a stationary mode indicator) to the communication unit 422 (such as the modem 423) . When the static mode indicator is enabled (such as set to “1” or “true” ) , the enabled static mode indicator may indicates the UE 120 remained stationary for the time period.

In some implementations, when the static mode indicator is enabled, the UE 120 may determine to modify a signal quality measurement associated with the 5G serving cell of the BS 110 in order to prevent frequent 5G NR cell handovers when the UE 120 has remained stationary for the time period. The UE 120 may determine a first signal quality measurement from signals (which may be referred to a reference signals) received from the 5G serving cell. Since the static mode indicator is enabled (indicating the UE 120 has remained stationary for the time period) , the UE 120 may modify the first signal quality measurement with a static bias offset. The static bias offset also may be referred to as a signal quality offset. The static bias offset may increase or improve the first signal quality measurement associated with the 5G serving cell in order to prevent frequent 5G NR cell handovers when the UE 120 has remained stationary for the time period, as described further herein.

In some implementations, the static bias offset may be selected based on a comparison of the first signal quality measurement to a static bias threshold. The static bias threshold also may be referred to as a signal quality threshold. In some implementations, the UE 120 may determine whether the first signal quality measurement is greater than the static bias threshold. If the first signal quality measurement is greater than the static bias threshold, the UE 120 may select a first offset for the static bias offset and may use the first offset to modify the first signal quality measurement. The first offset also may be referred to as a first offset value or a good signal static bias offset. If the first signal quality measurement is less than or equal to the static bias threshold, the UE 120 may select a second offset for the static bias offset and may use the second offset to modify the first signal quality measurement. The second offset also may be referred to as a second offset value or a weak signal static bias offset. In some implementations, the first offset may be greater than the second offset. The static bias threshold, the first offset, and the second offset may be preconfigured with various values and may be configurable. As a non-limiting example, the static bias threshold may be a configurable value between -115 and 95 decibel-milliwatts (dBm) , the first offset may be a configurable value between 2 and 6 decibels (dB) , and the second offset may be a configurable value between 0 and 2 dB. As another non-limiting example, the static bias threshold may be a configurable value between -100 and 80 dBm, the first offset may be a configurable value between 3 and 7 dB, and the second offset may be a configurable value between 0 and 3 dB.

In some implementations, in addition to determining the first signal quality measurement associated with the 5G serving cell, the UE 120 may determine one or more signal quality measurements associated with one or more 5G neighbor cells based on signals (such as reference signals) received from the one or more 5G neighbor cells. Each of the signal quality measurements associated with a corresponding 5G neighbor cell may be referred to as a second signal quality measurement associated with a neighbor cell. In some implementations, the UE 120 may determine whether to generate and transmit a handover measurement report to the BS 110 based on the modified first signal quality measurement associated with the 5G serving cell and the second signal quality measurement associated with the 5G neighbor cell.

In some implementations, after modifying the first signal quality measurement with the static bias offset, the UE 120 may determine whether a first handover condition for a first handover event is met or whether a second handover condition for a second handover event is met based on a comparison of the modified first signal quality measurement associated with the 5G serving cell and the second signal quality measurement associated with the 5G neighbor cell. The comparison of the signal quality measurements may be performed for each of the one or more 5G neighbor cells. The first handover condition for the first handover event may be an A3 event condition for an A3 event. The second condition for the second handover event may be an A5 event condition for an A5 event. The UE 120 may determine to prepare and transmit a handover measurement report when either the first handover condition for the first handover event is met or the second handover condition for the second handover event is met, as described further herein. By modifying the first signal quality measurement with the static bias offset (such as the first offset or the second offset) , the first and second handover conditions may be satisfied less frequently and thus the UE 120 may transmit a handover measurement report less frequently to the BS 110. Transmitting a handover measurement report less frequently to the BS 110 may result in the BS 110 initiating fewer cell handovers for the UE 120 when the UE 120 has remained stationary for the time period.

As shown in Section 5.5.4.4 of the TS 38.331, the A3 event condition for triggering the A3 event (which also may be referred to as Event A3) may be represented by the inequality (1) , which is reproduced below for reference.

Mn + Ofn + Ocn -Hys > Mp + Ofp + Ocp + Off (1)

Thus, the A3 event condition for the A3 event may be satisfied when the inequality (1) is true. The A3 event condition for the A3 event may not be satisfied when the inequality (1) is not true. The variables in the formula are defined as follows:

● Mn is the measurement result of the neighbor cell, not taking into account any offsets.

● Ofn is the measurement object specific offset of the reference signal of the neighbor cell.

● Ocn is the cell specific offset of the neighbor cell, and set to zero if not configured for the neighbor cell.

● Mp is the measurement result of the SpCell, not taking into account any offsets.

● Ofp is the measurement object specific offset of the SpCell.

● Ocp is the cell specific offset of the SpCell, and is set to zero if not configured for the SpCell.

● Hys is the hysteresis parameter for this event.

● Off is the offset parameter for this event.

● Mn, Mp are expressed in dBm in case of RSRP, or in dB in case of RSRQ and RS-SINR.

● Ofn, Ocn, Ofp, Ocp, Hys, Off are expressed in dB.

In some implementations, the SpCell may be the 5G serving cell and the Mp may be set to the modified first signal quality measurement associated with the 5G serving cell of the BS 110. The modified signal quality measurement may be derived by the UE 120 based on the static bias offset. For example, the modified first signal quality measurement may be derived by adding the static bias offset to the first signal quality measurement. The static bias offset may be either the first offset or the second offset. The Mn may be set to the second signal quality measurement associated with the 5G neighbor cell. In some implementations, each of the Ofn, Ocn, Ofp, Ocp, Hys, and Off variables of the inequality (1) may be configured by the BS 110 and provided to the UE 120. For example, the BS 110 may provide a measurement configuration message to the UE 120 that includes these variables of the inequality (1) . In an example deployment, the Off may be set to 1 dB and the Hys also may be set to 1 dB. Thus, the effect of the Off and the Hys in the inequality (1) may be disregarded since they equally adjust both sides of the inequality (1) . Similarly, in some implementations, the effect of the Ofn, the Ocn, the Ofp, and the Ocp may not modify the outcome of the inequality (1) . Thus, in its shortest form, the inequality (1) that triggers the UE 120 generating a handover measurement report for the A3 event may occur when the second signal quality measurement (such as the Mn) associated with the 5G neighbor cell is greater than the modified first signal quality measurement (such as the Mp) associated with the 5G serving cell. When the A3 event condition is not triggered, the UE 120 may not generate a handover measurement report. The static bias offset may increase or improve the first signal quality measurement associated with the 5G serving cell, and thus the A3 event condition may not be satisfied as frequently compared to when the first signal quality measurement is not modified by the static bias offset, which may prevent frequent 5G NR cell handovers when the UE 120 is stationary.

As shown in Section 5.5.4.6 of the TS 38.331, the A5 event condition for triggering the A5 event (which also may be referred to as Event A5) may be represented by the inequality (2) and the inequality (3) , which are reproduced below for reference.

Mp + Hys < Thresh1 (2)

Mn + Ofn + Ocn –Hys > Thresh2 (3)

Thus, the A5 event condition for the A5 event may be satisfied when both the inequality (2) and the inequality (3) are true. The A5 event condition for the A5 event may not be satisfied when either the inequality (2) or the inequality (3) are not true.

In some implementations, the SpCell may be the 5G serving cell and the Mp may be set to the modified first signal quality measurement associated with the 5G serving cell of the BS 110. The modified first signal quality measurement may be derived by adding the static bias offset to the first signal quality measurement. The static bias offset may be either the first offset or the second offset. The Mn may be set to the second signal quality measurement associated with the 5G neighbor cell. The Ofn, Ocn, and Hys variables may be the same as described with reference to inequality (1) associated with the A3 event. In some implementations, a handover measurement report for the A5 event may be triggered when the modified signal quality measurement (such as the Mp) associated with the 5G serving cell is less than a Thresh1 and the second signal quality measurement (such as the Mn) is greater than a Thresh2. In some implementations, each of the Ofn, Ocn, Hys, Thresh1, and Thresh2 variables of the inequality (2) and the inequality (3) may be configured by the BS 110 and provided to the UE 120. For example, the BS 110 may provide a measurement configuration message to the UE 120 that includes these variables of the inequality (2) and the inequality (3) . When the A5 event condition is not triggered, the UE 120 may not generate a handover measurement report. The static bias offset may increase or improve the first signal quality measurement associated with the 5G serving cell, and thus the A5 event condition may not be satisfied as frequently compared to when the first signal quality measurement is not modified by the static bias offset, which may prevent frequent 5G NR cell handovers when the UE 120 is stationary.

In some implementations, the UE 120 may continue to use a modified first signal quality measurement to determine whether the first handover condition of the first handover event (such as the A3 event) is satisfied or the second handover conditions of the second handover event (such as the A5 event) satisfied until motion is detected by the UE 120. In some implementations, while the static mode indicator is enabled, the UE 120 may continue to monitor the sensor information to determine whether the UE 120 remains stationary or whether motion is detected. For example, the application processor 426 may continue to monitor the sensor information obtained from the sensors 428 to determine whether the UE 120 remains stationary or whether motion is detected. In some implementations, if motion is detected, the UE 120 may stop using a modified first signal quality measurement for the 5G serving cell. For example, if the application processor 426 determines the UE 120 has moved (or motion has been detected) based on the sensor information, the application processor 426 may disable the static mode indicator to indicate that the UE 120 has moved. For example, the application processor 426 may provide a disabled static mode indicator to the communication unit 422 (such as the modem 423) that indicates the UE 120 has moved or motion has been detected at the UE 120. In some implementations, when the static mode indicator is disabled (such as set to “0” or “false” ) , the UE 120 may determine that motion has been detected and may stop using a modified first signal quality measurement for the 5G serving cell. For example, the UE 120 may begin to use a first signal quality measurement (that is not modified by the static bias offset) to determine whether the first handover condition of the first handover event (such as the A3 event) is satisfied or the second handover conditions of the second handover event (such as the A5 event) is satisfied.

Figure 5 depicts a flowchart 500 with example operations performed by an apparatus of a UE for preventing frequent 5G NR cell handovers in an NSA EN-DC mode when the UE is stationary.

At block 510, the apparatus of the UE may determine, while the UE is connected with a serving cell associated with a 5G NR RAT of a WWAN, a first signal quality measurement from signals obtained from the serving cell and a second signal quality measurement from signals obtained from a neighbor cell associated with the 5G NR RAT. In some implementations, the WWAN may include a 5G NR BS and an LTE BS. The 5G NR BS may include the serving cell. In some implementations, the LTE BS may be configured as a MN and the 5G NR BS may be configured as a SN. In some implementations, the LTE BS and the 5G NR BS may have an NSA architecture and may be configured to operate in an EN-DC mode.

At block 520, the apparatus of the UE may determine whether the UE remained stationary for a time period. In some implementations, the apparatus of the UE may obtain sensor information from one or more sensors (such as an accelerometer) to determine whether the UE remained stationary for the time period.

At block 530, the apparatus of the UE may modify the first signal quality measurement associated with the serving cell with a static bias offset in response to determining the UE remained stationary for the time period.

At block 540, the apparatus of the UE may determine whether to output a handover measurement report for transmission to the serving cell based on the modified first signal quality measurement associated with the serving cell and the second signal quality measurement associated with the neighbor cell.

Figure 6 depicts a flowchart 600 with example operations performed by an apparatus of a UE for preventing frequent 5G NR cell handovers in an NSA EN-DC mode when the UE 120 is stationary.

At block 610, the apparatus of the UE may determine to begin operating in an NSA EN-DC mode.

At block 620, the apparatus of the UE may obtain a measurement configuration associated with the A3 and A5 events from the 5G serving cell. For example, the UE may obtain the variables that are used in the inequality (1) associated with the A3 event condition and the inequalities (2) and (3) associated with the A5 event condition, as described in Figure 4.

At block 630, the apparatus of the UE may determine whether the UE remained stationary for a time period.

At block 640, the apparatus of the UE may determine whether the static mode indicator was enabled. If the UE remained stationary for the time period, the static mode indicator may be enabled, and the operations may continue at block 640. Otherwise, if the UE did not remain stationary for the time period, the static mode indicator may not be enabled, and the operations may continue at block 670.

At block 650, the apparatus of the UE may determine whether the first signal quality measurement associated with the 5G serving cell is greater than a static bias threshold. If the first signal quality measurement is greater than the static bias threshold, the operations may continue at block 652. Otherwise, if the first signal quality measurement is less than or equal to the static bias threshold, the operations may continue at block 654.

At block 652, the apparatus of the UE may select a first offset for the static bias offset. The first offset may be referred to as a good signal static bias offset.

At block 654, the apparatus of the UE may select a second offset for the static bias offset. The second offset may be referred to as a weak signal static bias offset.

At block 660, the apparatus of the UE may modify the first signal quality measurement associated with the 5G serving cell with the static bias offset. For example, the first signal quality measurement may be modified with either the first offset or the second offset.

At block 670, the apparatus of the UE may determine whether to generate a handover measurement report based on whether the A3 or A5 event conditions are satisfied. When the static mode indicator is enabled, the modified first signal quality measurement associated with the 5G serving cell may be used to determine whether the A3 or A5 event conditions are satisfied. When the static mode indicator is not enabled, the first signal quality measurement associated with the 5G serving cell (without modification) may be used to determine whether the A3 or A5 event conditions are satisfied.

Figure 7 shows a block diagram of an example wireless communication apparatus 700. In some implementations, the wireless communication apparatus 700 can be an example of a device for use in a UE, such as the UE 120 described with reference to Figure 4. In some implementations, the wireless communication apparatus 700 can be an example of a device for use in a BS, such as the BS 110 described with reference to Figure 4. The wireless communication apparatus 700 is capable of transmitting (or outputting for transmission) and receiving wireless communications.

The wireless communication apparatus 700 can be, or can include, a chip, system on chip (SoC) , chipset, package or device. The term “system-on-chip” (SoC) is used herein to refer to a set of interconnected electronic circuits typically, but not exclusively, including one or more processors, a memory, and a communication interface. The SoC may include a variety of different types of processors and processor cores, such as a general purpose processor, a central processing unit (CPU) , a digital signal processor (DSP) , a graphics processing unit (GPU) , an accelerated processing unit (APU) , a sub-system processor, an auxiliary processor, a single-core processor, and a multicore processor. The SoC may further include other hardware and hardware combinations, such as a field programmable gate array (FPGA) , a configuration and status register (CSR) , an application-specific integrated circuit (ASIC) , other programmable logic device, discrete gate logic, transistor logic, registers, performance monitoring hardware, watchdog hardware, counters, and time references. SoCs may be integrated circuits (ICs) configured such that the components of the IC reside on the same substrate, such as a single piece of semiconductor material (such as, for example, silicon) .

The term “system in a package” (SIP) is used herein to refer to a single module or package that may contain multiple resources, computational units, cores and/or processors on two or more IC chips, substrates, or SoCs. For example, a SIP may include a single substrate on which multiple IC chips or semiconductor dies are stacked in a vertical configuration. Similarly, the SIP may include one or more multi-chip modules (MCMs) on which multiple ICs or semiconductor dies are packaged into a unifying substrate. A SIP also may include multiple independent SoCs coupled together via high speed communication circuitry and packaged in close proximity, such as on a single motherboard or in a single mobile communication device. The proximity of the SoCs facilitates high speed communications and the sharing of memory and resources.

The term “multicore processor” is used herein to refer to a single IC chip or chip package that contains two or more independent processing cores (for example a CPU core, IP core, GPU core, among other examples) configured to read and execute program instructions. An SoC may include multiple multicore processors, and each processor in an SoC may be referred to as a core. The term “multiprocessor” may be used herein to refer to a system or device that includes two or more processing units configured to read and execute program instructions.

The wireless communication apparatus 700 may include one or more modems 702. In some implementations, the one or more modems 702 (collectively “the modem 702” ) may include a WWAN modem (for example, a 3GPP 4G LTE or 5G compliant modem) . In some implementations, the wireless communication apparatus 700 also includes one or more radios 704 (collectively “the radio 704” ) . In some implementations, the wireless communication apparatus 700 further includes one or more processors, processing blocks or processing elements 706 (collectively “the processor 706” ) and one or more memory blocks or elements 708 (collectively “the memory 708” ) .

The modem 702 can include an intelligent hardware block or device such as, for example, an application-specific integrated circuit (ASIC) among other possibilities. The modem 702 is generally configured to implement a PHY layer. For example, the modem 702 is configured to modulate packets and to output the modulated packets to the radio 704 for transmission over the wireless medium. The modem 702 is similarly configured to obtain modulated packets received by the radio 704 and to demodulate the packets to provide demodulated packets. In addition to a modulator and a demodulator, the modem 702 may further include digital signal processing (DSP) circuitry, automatic gain control (AGC) , a coder, a decoder, a multiplexer and a demultiplexer. For example, while in a transmission mode, data obtained from the processor 706 is provided to a coder, which encodes the data to provide encoded bits. The encoded bits are mapped to points in a modulation constellation (using a selected MCS) to provide modulated symbols. The modulated symbols may be mapped to a number NSS of spatial streams or a number NSTS of space-time streams. The modulated symbols in the respective spatial or space-time streams may be multiplexed, transformed via an inverse fast Fourier transform (IFFT) block, and subsequently provided to the DSP circuitry for Tx windowing and filtering. The digital signals may be provided to a digital-to-analog converter (DAC) . The resultant analog signals may be provided to a frequency upconverter, and ultimately, the radio 704. In implementations involving beamforming, the modulated symbols in the respective spatial streams are precoded via a steering matrix prior to their provision to the IFFT block.

While in a reception mode, digital signals received from the radio 704 are provided to the DSP circuitry, which is configured to acquire a received signal, for example, by detecting the presence of the signal and estimating the initial timing and frequency offsets. The DSP circuitry is further configured to digitally condition the digital signals, for example, using channel (narrowband) filtering, analog impairment conditioning (such as correcting for I/Q imbalance) , and applying digital gain to ultimately obtain a narrowband signal. The output of the DSP circuitry may be fed to the AGC, which is configured to use information extracted from the digital signals, for example, in one or more received training fields, to determine an appropriate gain. The output of the DSP circuitry also is coupled with the demodulator, which is configured to extract modulated symbols from the signal and, for example, compute the logarithm likelihood ratios (LLRs) for each bit position of each subcarrier in each spatial stream. The demodulator is coupled with the decoder, which may be configured to process the LLRs to provide decoded bits. The decoded bits from all of the spatial streams are fed to the demultiplexer for demultiplexing. The demultiplexed bits may be descrambled and provided to the MAC layer (the processor 706) for processing, evaluation, or interpretation.

The radio 704 generally includes at least one radio frequency (RF) transmitter (or “transmitter chain” ) and at least one RF receiver (or “receiver chain” ) , which may be combined into one or more transceivers. For example, the RF transmitters and receivers may include various DSP circuitry including at least one power amplifier (PA) and at least one low-noise amplifier (LNA) , respectively. The RF transmitters and receivers may, in turn, be coupled to one or more antennas. For example, in some implementations, the wireless communication apparatus 700 can include, or be coupled with, multiple transmit antennas (each with a corresponding transmit chain) and multiple receive antennas (each with a corresponding receive chain) . The symbols output from the modem 702 are provided to the radio 704, which transmits the symbols via the coupled antennas. Similarly, symbols received via the antennas are obtained by the radio 704, which provides the symbols to the modem 702.

The processor 706 can include an intelligent hardware block or device such as, for example, a processing core, a processing block, a central processing unit (CPU) , a microprocessor, a microcontroller, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a programmable logic device (PLD) such as a field programmable gate array (FPGA) , discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processor 706 processes information received through the radio 704 and the modem 702, and processes information to be output through the modem 702 and the radio 704 for transmission through the wireless medium. In some implementations, the processor 706 may generally control the modem 702 to cause the modem to perform various operations described throughout.

The memory 708 can include tangible storage media such as random-access memory (RAM) or read-only memory (ROM) , or combinations thereof. The memory 708 also can store non-transitory processor-or computer-executable software (SW) code containing instructions that, when executed by the processor 706, cause the processor to perform various operations described herein for wireless communication, including the generation, transmission, reception and interpretation of MPDUs, frames or packets. For example, various functions of components disclosed herein, or various blocks or steps of a method, operation, process or algorithm disclosed herein, can be implemented as one or more modules of one or more computer programs.

Figure 8 shows a block diagram of an example mobile communication device 804. For example, the mobile communication device 804 can be an example implementation of the UE 120 described herein. The mobile communication device 804 includes a wireless communication apparatus (WCA) 815. For example, the WCA 815 may be an example implementation of the wireless communication apparatus 700 described with reference to Figure 7. The mobile communication device 804 also includes one or more antennas 825 coupled with the WCA 815 to transmit and receive wireless communications. The mobile communication device 804 additionally includes an application processor 835 coupled with the WCA 815, and a memory 845 coupled with the application processor 835. In some implementations, the mobile communication device 804 further includes a UI 855 (such as a touchscreen or keypad) and a display 865, which may be integrated with the UI 855 to form a touchscreen display. In some implementations, the mobile communication device 804 may further include one or more sensors 875 such as, for example, one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors. Ones of the aforementioned components can communicate with other ones of the components directly or indirectly, over at least one bus. The mobile communication device 804 further includes a housing that encompasses the WCA 815, the application processor 835, the memory 845, and at least portions of the antennas 825, UI 855, and display 865.

Figures 1–8 and the operations described herein are examples meant to aid in understanding example implementations and should not be used to limit the potential implementations or limit the scope of the claims. Some implementations may perform additional operations, fewer operations, operations in parallel or in a different order, and some operations differently.

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

As used herein, the term “component” is intended to be broadly construed as hardware, firmware, or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, or a combination of hardware and software. As used herein, the phrase “based on” is intended to be broadly construed to mean “based at least in part on. ”

Some aspects are described herein in connection with thresholds. As used herein, satisfying a threshold may refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, or the like.

As used herein, a phrase referring to “at least one of” or “one or more of” a list of items refers to any combination of those items, including single members. For example, “at least one of: a, b, or c” is intended to cover the possibilities of: a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a and b and c.

The various illustrative components, logic, logical blocks, modules, circuits, operations and algorithm processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware or software, including the structures disclosed in this specification and the structural equivalents thereof. The interchangeability of hardware, firmware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and processes described above. Whether such functionality is implemented in hardware, firmware or software depends upon the particular application and design constraints imposed on the overall system.

The hardware and data processing apparatus used to implement the various illustrative components, logics, logical blocks, modules and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose single-or multi-chip processor, a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device (PLD) , 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, or, any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, for example, 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. In some implementations, particular processes, operations and methods may be performed by circuitry that is specific to a given function.

As described above, in some aspects implementations of the subject matter described in this specification can be implemented as software. For example, various functions of components disclosed herein, or various blocks or steps of a method, operation, process or algorithm disclosed herein can be implemented as one or more modules of one or more computer programs. Such computer programs can include non-transitory processor-or computer-executable instructions encoded on one or more tangible processor-or computer-readable storage media for execution by, or to control the operation of, data processing apparatus including the components of the devices described herein. By way of example, and not limitation, such storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store program code in the form of instructions or data structures. Combinations of the above should also be included within the scope of storage media.

Various modifications to the implementations described in this disclosure may be readily apparent to persons having ordinary skill in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.

Additionally, various features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. As such, although features may be described above as acting in particular combinations, and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one or more example processes in the form of a flowchart or flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In some circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.

Claims

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

determining, while the UE is connected with a serving cell associated with a 5G New Radio (NR) radio access technology (RAT) of a wireless wide area network (WWAN) , a first signal quality measurement from signals obtained from the serving cell and a second signal quality measurement from signals obtained from a neighbor cell associated with the 5G NR RAT;

determining whether the UE remained stationary for a time period;

modifying the first signal quality measurement associated with the serving cell with a static bias offset in response to determining the UE remained stationary for the time period; and

determining whether to output a handover measurement report for transmission to the serving cell based on the modified first signal quality measurement associated with the serving cell and the second signal quality measurement associated with the neighbor cell.
The method of claim 1, wherein:

the WWAN includes a 5G NR base station (BS) and a Long-Term Evolution (LTE) BS, the 5G NR BS including the serving cell;

the UE is connected with both the LTE BS and the 5G NR BS; and

the LTE BS is configured as a master node (MN) and the 5G NR BS is configured as a secondary node (SN) .
The method of claim 2, wherein the LTE BS and the 5G NR BS have a non-standalone (NSA) architecture and are configured to operate in an Evolved Universal Terrestrial Radio Access (E-UTRA) NR Dual Connectivity (EN-DC) mode.
The method of claim 1, further comprising:

determining whether the first signal quality measurement associated with the serving cell is greater than a static bias threshold;

selecting a first offset of the static bias offset in response to determining the first signal quality measurement is greater than the static bias threshold; and

modifying the first signal quality measurement with the first offset in response to determining the UE remained stationary for the time period.
The method of claim 4, further comprising:

selecting a second offset of the static bias offset in response to determining the first signal quality measurement is not greater than the static bias threshold; and

modifying the first signal quality measurement with the second offset in response to determining the UE remained stationary for the time period.
The method of claim 5, wherein the first offset is greater than the second offset.
The method of claim 1, wherein the WWAN includes a 5G NR BS, the 5G NR BS including the serving cell and the neighbor cell.
The method of claim 1, wherein the WWAN includes a first 5G NR BS and a second 5G NR BS, the first 5G NR BS including the serving cell and the second 5G NR BS including the neighbor cell.
The method of claim 1, wherein determining whether to output the handover measurement report for transmission to the serving cell further comprises:

determining whether a first handover condition associated with a first handover event is met based, at least in part, on a comparison of the modified first signal quality measurement and the second signal quality measurement; and

determining whether to output the handover measurement report for transmission to the serving cell based, at least in part, on the comparison.
The method of claim 9, wherein the first handover event is an A3 event, and the first handover condition is an A3 event condition.
The method of claim 1, wherein determining whether to output the handover measurement report for transmission to the serving cell further comprises:

determining whether a second handover condition associated with a second handover event is met based, at least in part, on a first comparison of the modified first signal quality measurement with a first signal quality threshold and a second comparison of the second signal quality measurement with a second signal quality threshold; and

determining whether to output the handover measurement report for transmission to the serving cell based, at least in part, on the first comparison and the second comparison.
The method of claim 11, wherein the second handover event is an A5 event, and the second handover condition is an A5 event condition.
The method of claim 1, wherein modifying the first signal quality measurement associated with the serving cell with the static bias offset reduces a frequency of transmission of the handover measurement report.
The method of claim 1, wherein determining whether the UE remained stationary for the time period comprises:

determining whether the UE remained stationary for the time period based on sensor information.
The method of claim 1, wherein determining whether the UE remained stationary for the time period comprises:

determining whether an application processor of the UE provided a static mode indicator to a modem of the UE, the static mode indicator indicating the UE remained stationary for the time period.
The method of claim 1, wherein the first signal quality measurement and the second signal quality measurement are reference signal received power (RSRP) measurements, reference signal received quality (RSRQ) measurements, or signal-to-interference-plus-noise ratio (SINR) measurements.
The method of claim 1, wherein the time period is between 5 and 300 seconds.
The method of claim 1, wherein the time period is a configurable time period.
An apparatus of a user equipment (UE) for wireless communication, comprising:

one or more interfaces for communicating via a wireless wide area network (WWAN) ; and

one or more processors configured to:

determine, while the UE is connected with a serving cell associated with a 5G New Radio (NR) radio access technology (RAT) of the WWAN, a first signal quality measurement from signals obtained from the serving cell and a second signal quality measurement from signals obtained from a neighbor cell associated with the 5G NR RAT;

determine whether the UE remained stationary for a time period;

modify the first signal quality measurement associated with the serving cell with a static bias offset in response to a determination that the UE remained stationary for the time period; and

determine whether to output a handover measurement report via the one or more interfaces for transmission to the serving cell based on the modified first signal quality measurement associated with the serving cell and the second signal quality measurement associated with the neighbor cell.
The apparatus of claim 19, wherein:

the WWAN includes a 5G NR base station (BS) and a Long-Term Evolution (LTE) BS, the 5G NR BS including the serving cell;

the UE is connected with both the LTE BS and the 5G NR BS; and

the LTE BS is configured as a master node (MN) and the 5G NR BS is configured as a secondary node (SN) .
The apparatus of claim 20, wherein the LTE BS and the 5G NR BS have a non-standalone (NSA) architecture and are configured to operate in an Evolved Universal Terrestrial Radio Access (E-UTRA) NR Dual Connectivity (EN-DC) mode.
The apparatus of claim 19, wherein the one or more processors are further configured to:

determine whether the first signal quality measurement associated with the serving cell is greater than a static bias threshold;

select a first offset of the static bias offset in response to a determination that the first signal quality measurement is greater than the static bias threshold; and

modify the first signal quality measurement with the first offset in response to a determination that the UE remained stationary for the time period.
The apparatus of claim 22, wherein the one or more processors are further configured to:

select a second offset of the static bias offset in response to a determination that the first signal quality measurement is not greater than the static bias threshold; and

modify the first signal quality measurement with the second offset in response to a determination that the UE remained stationary for the time period.
The apparatus of claim 23, wherein the first offset is greater than the second offset.
The apparatus of claim 19, wherein the WWAN includes a 5G NR BS, the 5G NR BS including the serving cell and the neighbor cell.
The apparatus of claim 19, wherein the WWAN includes a first 5G NR BS and a second 5G NR BS, the first 5G NR BS including the serving cell and the second 5G NR BS including the neighbor cell.
The apparatus of claim 19, wherein the one or more processors are further configured to:

determine whether a first handover condition associated with a first handover event is met based, at least in part, on a comparison of the modified first signal quality measurement and the second signal quality measurement; and

determine whether to output via the one or more interfaces the handover measurement report for transmission to the serving cell based, at least in part, on the comparison.
The apparatus of claim 27, wherein the first handover event is an A3 event, and the first handover condition is an A3 event condition.
The apparatus of claim 19, wherein the one or more processors are further configured to:

determine whether a second handover condition associated with a second handover event is met based, at least in part, on a first comparison of the modified first signal quality measurement with a first signal quality threshold and a second comparison of the second signal quality measurement with a second signal quality threshold; and

determine whether to output via the one or more interfaces the handover measurement report for transmission to the serving cell based, at least in part, on the first comparison and the second comparison.
The apparatus of claim 29, wherein the second handover event is an A5 event, and the second handover condition is an A5 event condition.
The apparatus of claim 19, wherein the first signal quality measurement associated with the serving cell is modified with the static bias offset to reduce a frequency of transmission of the handover measurement report.
The apparatus of claim 19, wherein the one or more processors are further configured to:

determine whether the UE remained stationary for the time period based on sensor information.
The apparatus of claim 19, wherein the first signal quality measurement and the second signal quality measurement are reference signal received power (RSRP) measurements, reference signal received quality (RSRQ) measurements, or signal-to-interference-plus-noise ratio (SINR) measurements.
A computer-readable medium having stored therein instructions which, when executed by a processor of a user equipment (UE) , causes the UE to perform any one of the method claims 1–18.
An apparatus, comprising:

means for implementing any one of the method claims 1–18.