WO2020257997A1

WO2020257997A1 - Holding measurement report for unexpectedly quick handover

Info

Publication number: WO2020257997A1
Application number: PCT/CN2019/092612
Authority: WO
Inventors: Nanrun WU; Jie Mao; Jianqiang Zhang
Original assignee: Qualcomm Incorporated
Priority date: 2019-06-24
Filing date: 2019-06-24
Publication date: 2020-12-30

Abstract

Certain aspects of the present disclosure provide techniques for delaying transmission of a measurement report associated with causing an unexpectedly quick handover by a UE from a serving cell to another cell. In an exemplary method, a user equipment (UE) may detect one or more conditions associated with an unexpected handover (HO) of the UE from a serving cell to a target cell and delay transmitting a measurement report in response to detecting the one or more conditions.

Description

HOLDING MEASUREMENT REPORT FOR UNEXPECTEDLY QUICK HANDOVER

BACKGROUND

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for delaying transmission of a measurement report associated with causing an unexpectedly quick handover by a UE from a serving cell to another cell.

Description of Related Art

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc. ) . Examples of such multiple-access systems include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE Advanced (LTE-A) systems, code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems, to name a few.

In some examples, a wireless multiple-access communication system may include a number of base stations (BSs) , which are each capable of simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs) . In an LTE or LTE-A network, a set of one or more base stations may define an eNodeB (eNB) . In other examples (e.g., in a next generation, a new radio (NR) , or 5G network) , a wireless multiple access communication system may include a number of distributed units (DUs) (e.g., edge units (EUs) , edge nodes (ENs) , radio heads (RHs) , smart radio heads (SRHs) , transmission reception points (TRPs) , etc. ) in communication with a number of central units (CUs) (e.g., central nodes (CNs) , access node controllers (ANCs) , etc. ) , where a set of one or more DUs, in communication with a CU, may define an access node (e.g., which may be referred to as a BS, next generation NodeB (gNB or gNodeB) , TRP, etc. ) . A BS or DU may communicate with a set of UEs on downlink channels (e.g., for transmissions from a BS or DU to a UE) and uplink channels (e.g., for transmissions from a UE to a BS or DU) .

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. New radio (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is a set of enhancements to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL) . To these ends, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in NR and LTE technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

SUMMARY

The systems, methods, and devices of the disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure as expressed by the claims which follow, some features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this disclosure provide advantages that include improved communications between access points and stations in a wireless network.

Certain aspects provide a method for wireless communication performed by a user equipment (UE) . The method generally includes detecting one or more conditions associated with an unexpected handover (HO) of the UE from a serving cell to a target cell, and delaying transmitting a measurement report in response to detecting the one or more conditions.

Certain aspects provide an apparatus for wireless communication. The apparatus generally includes a processor configured to detect one or more conditions associated with an unexpected handover (HO) of the apparatus from a serving cell to a target cell and delay transmitting a measurement report in response to detecting the one or more conditions, and a memory coupled with the processor.

Certain aspects provide an apparatus for wireless communication. The apparatus generally includes means for detecting one or more conditions associated with an unexpected handover (HO) of the apparatus from a serving cell to a target cell, and means for delaying transmitting a measurement report in response to detecting the one or more conditions.

Certain aspects provide a computer-readable medium for wireless communication performed by a user equipment (UE) . The computer-readable medium includes instructions that, when executed by a processing system, cause the processing system to perform operations generally including detecting one or more conditions associated with an unexpected handover (HO) of the UE from a serving cell to a target cell, and delaying transmitting a measurement report in response to detecting the one or more conditions.

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

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 1 is a block diagram conceptually illustrating an example telecommunications system, in accordance with certain aspects of the present disclosure.

FIG. 2 is a block diagram illustrating an example architecture of a distributed radio access network (RAN) , in accordance with certain aspects of the present disclosure.

FIG. 3 is a set of exemplary graphs of cell measurements by a UE that performs an unexpected handover, in accordance with certain aspects of the present disclosure.

FIG. 4 is a flow diagram illustrating example operations for wireless communication by a user equipment (UE) , in accordance with certain aspects of the present disclosure.

FIG. 5 illustrates a communications device that may include various components configured to perform operations for the techniques disclosed herein in accordance with aspects of the present disclosure.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for delaying transmission of a measurement report associated with causing an unexpectedly quick handover by a UE from a serving cell to another cell. In currently known wireless communications standards (e.g., LTE) for UE mobility, a UE monitors (i.e., measures and tracks) serving cell reference signal received power (RSRP) as well as inter-frequency RSRP for other cells. The configuration of the cells and frequencies for the inter-frequency monitoring is received by the UE from the UE’s serving base station (e.g., a serving evolved NodeB (eNB) ) . RSRP of the UE’s serving cell and the inter-frequency RSRPs are measured at different rates or periodicities in a trade-off between power consumption for the measurements and performance of the UE. For example, serving cell RSRP may be measured every ten milliseconds by a UE, while inter-frequency RSRP may be measured less than once per second, such as once every 1.28 seconds or once every 2.56 seconds. When the measurements of the serving cell indicate the UE is experiencing poor signal quality or low signal strength from the serving cell, the UE may report the serving cell and inter-frequency measurements. In response to receiving a measurement report from the UE, the network (e.g., a network entity, such as a mobility management entity) may send commands for the UE to handover (HO) from the serving cell to another cell.

The previously mentioned inter-frequency RSRP measurements are kept (i.e., retained) in a higher layer of the UE’s protocol stack once the UE is in a radio resource control (RRC) connected state with the network, even if the UE performs a HO to another cell. Many times it has been observed that, when a UE has just completed a HO, a new unexpected HO may be triggered quickly by the UE reporting these retained inter-frequency RSRP measurements that were obtained before the just completed HO and were not updated for a long time (e.g., more than one second) . This unexpected HO may lead to a radio link failure (RLF) , if the cell to which the UE hands over (i.e., the cell associated with the retained inter-frequency RSRP measurements) has poor signal quality to the UE (i.e., the RSRQ measurement of the cell is low) . In addition, the UE may ignore some cells that are newly configured (i.e., by the network) on the UE that have better inter-frequency RSRP because the unexpected HO occurs so quickly that the UE does not have time to measure the newly configured cells. The impact of an unexpected measurement report (MR) and its unexpected HO, as described above, may seriously affect UE performance. The unexpected HO may cause significant delay in switching (i.e., handing over) to the correct cell and/or even prevent the UE from switching to the correct cell. Moreover, an unexpected HO sometimes causes a radio link failure between the UE and a serving cell.

The following description provides examples, and is not limiting of the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects.

The techniques described herein may be used for various wireless communication technologies, such as 3GPP Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , single-carrier frequency division multiple access (SC-FDMA) , time division synchronous code division multiple access (TD-SCDMA) , and other networks. The terms “network” and “system” are often used interchangeably.

A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA) , cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM) . An OFDMA network may implement a radio technology such as NR (e.g. 5G RA) , Evolved UTRA (E-UTRA) , Ultra Mobile Broadband (UMB) , IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS) . LTE and LTE-A are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP) . cdma2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) .

New Radio (NR) is an emerging wireless communications technology under development in conjunction with the 5G Technology Forum (5GTF) . NR access (e.g., 5G NR) may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or beyond) , millimeter wave (mmW) targeting high carrier frequency (e.g., 25 GHz or beyond) , massive machine type communications MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra-reliable low-latency communications (URLLC) . These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTI) to meet respective quality of service (QoS) requirements. In addition, these services may co-exist in the same subframe.

The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, while aspects may be described herein using terminology commonly associated with 3G and/or 4G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as 5G and later, including NR technologies.

FIG. 1 illustrates an example wireless communication network 100 in which aspects of the present disclosure may be performed. For example, the wireless communication network 100 may be an NR system (e.g., a 5G NR network) . For example, as shown in FIG. 1, the UE 120a has a hold MR for unexpectedly quick HO module that may be configured to detect one or more conditions associated with an unexpected handover (HO) of the UE from a serving cell to a target cell and delay transmitting a measurement report in response to detecting the one or more conditions, according to aspects described herein.

As illustrated in FIG. 1, the wireless communication network 100 may include a number of base stations (BSs) 110 and other network entities. A BS may be a station that communicates with user equipments (UEs) . Each BS 110 may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to a coverage area of a Node B (NB) and/or a NB subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term “cell” and BS, next generation NodeB (gNB or gNodeB) , access point (AP) , distributed unit (DU) , carrier, or transmission reception point (TRP) may be used interchangeably. In some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS. In some examples, the BSs may be interconnected to one another and/or to one or more other BSs or network nodes (not shown) in wireless communication network 100 through various types of backhaul interfaces, such as a direct physical connection, a wireless connection, a virtual network, or the like using any suitable transport network.

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

A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cells. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having an association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG) , UEs for users in the home, etc. ) . A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in FIG. 1, the

BSs

110a, 110b and 110c may be macro BSs for the

macro cells

102a, 102b and 102c, respectively. The BS 110x may be a pico BS for a pico cell 102x. The BSs 110y and 110z may be femto BSs for the

femto cells

102y and 102z, respectively. A BS may support one or multiple (e.g., three) cells.

Wireless communication network 100 may also include relay stations. A relay station is a station that receives a transmission of data and/or other information from an upstream station (e.g., a BS or a UE) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE or a BS) . A relay station may also be a UE that relays transmissions for other UEs. In the example shown in FIG. 1, a relay station 110r may communicate with the BS 110a and a UE 120r in order to facilitate communication between the BS 110a and the UE 120r. A relay station may also be referred to as a relay BS, a relay, etc.

Wireless communication network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BS, pico BS, femto BS, relays, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different impact on interference in the wireless communication network 100. For example, macro BS may have a high transmit power level (e.g., 20 Watts) whereas pico BS, femto BS, and relays may have a lower transmit power level (e.g., 1 Watt) .

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 techniques described herein may be used for both synchronous and asynchronous operation.

A network controller 130 may couple to a set of BSs and provide coordination and control for these BSs. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with one another (e.g., directly or indirectly) via wireless or wireline backhaul.

The UEs 120 (e.g., 120x, 120y, etc. ) may be dispersed throughout the wireless communication network 100, and each UE may be stationary or mobile. A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE) , a cellular phone, a smart phone, a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or medical equipment, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, a smart bracelet, etc. ) , an entertainment device (e.g., a music device, a video device, a satellite radio, etc. ) , a vehicular component or sensor, a smart meter/sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium. Some UEs may be considered machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., that may communicate with a BS, another device (e.g., remote device) , or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

Certain wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers may be 15 kHz and the minimum resource allocation (called a “resource block” (RB) ) may be 12 subcarriers (or 180 kHz) . Consequently, the nominal Fast Fourier Transfer (FFT) size may be equal to 128, 256, 512, 1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz) , respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (e.g., 6 RBs) , and there may be 1, 2, 4, 8, or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively. In LTE, the basic transmission time interval (TTI) or packet duration is the 1 ms subframe. In NR, a subframe is still 1 ms, but the basic TTI is referred to as a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16, …slots) depending on the subcarrier spacing. The NR RB is 12 consecutive frequency subcarriers. NR may support a base subcarrier spacing of 15 KHz and other subcarrier spacing may be defined with respect to the base subcarrier spacing, for example, 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing.

NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. In some examples, MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. In some examples, multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells.

In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity. Base stations are not the only entities that may function as a scheduling entity. In some examples, a UE may function as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs) , and the other UEs may utilize the resources scheduled by the UE for wireless communication. In some examples, a UE may function as a scheduling entity in a peer-to-peer (P2P) network, and/or in a mesh network. In a mesh network example, UEs may communicate directly with one another in addition to communicating with a scheduling entity.

In some examples, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh, and/or various other suitable applications. Generally, a sidelink signal may refer to a signal communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying that communication through the scheduling entity (e.g., UE or BS) , even though the scheduling entity may be utilized for scheduling and/or control purposes. In some examples, the sidelink signals may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum) .

In FIG. 1, a solid line with double arrows indicates desired transmissions between a UE and a serving BS, which is a BS designated to serve the UE on the downlink and/or uplink. A finely dashed line with double arrows indicates potentially interfering transmissions between a UE and a BS.

FIG. 2 illustrates example components of BS 110 and UE 120 (e.g., in the wireless communication network 100 of FIG. 1) , which may be used to implement aspects of the present disclosure. For example, antennas 252,

processors

266, 258, 264, and/or controller/processor 280 of the UE 120 and/or antennas 234,

processors

220, 230, 238, and/or controller/processor 240 of the BS 110 may be used to perform the various techniques and methods described herein. For example, as shown in FIG. 2, the controller/processor 280 of the UE 120 has a hold MR for unexpectedly quick HO module that may be configured to detect one or more conditions associated with an unexpected handover (HO) of the UE from a serving cell to a target cell and delay transmitting a measurement report in response to detecting the one or more conditions, according to aspects described herein.

At the BS 110, a transmit processor 220 may receive data from a data source 212 and control information from a controller/processor 240. The control information may be for the physical broadcast channel (PBCH) , physical control format indicator channel (PCFICH) , physical hybrid ARQ indicator channel (PHICH) , physical downlink control channel (PDCCH) , group common PDCCH (GC PDCCH) , etc. The data may be for the physical downlink shared channel (PDSCH) , etc. The processor 220 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor 220 may also generate reference symbols, such as for the primary synchronization signal (PSS) , secondary synchronization signal (SSS) , and cell-specific reference signal (CRS) . A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) 232a-232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM, etc. ) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators 232a-232t may be transmitted via the antennas 234a-234t, respectively.

At the UE 120, the antennas 252a-252r may receive the downlink signals from the BS 110 and may provide received signals to the demodulators (DEMODs) in transceivers 254a-254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM, etc. ) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all the demodulators 254a-254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120 to a data sink 260, and provide decoded control information to a controller/processor 280.

On the uplink, at UE 120, a transmit processor 264 may receive and process data (e.g., for the physical uplink shared channel (PUSCH) ) from a data source 262 and control information (e.g., for the physical uplink control channel (PUCCH) from the controller/processor 280. The transmit processor 264 may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS) ) . The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by the demodulators in transceivers 254a-254r (e.g., for SC-FDM, etc. ) , and transmitted to the base station 110. At the BS 110, the uplink signals from the UE 120 may be received by the antennas 234, processed by the modulators 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 the UE 120. The receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to the controller/processor 240.

The controllers/

processors

240 and 280 may direct the operation at the BS 110 and the UE 120, respectively. The controller/processor 240 and/or other processors and modules at the BS 110 may perform or direct the execution of processes for the techniques described herein. The

memories

242 and 282 may store data and program codes for BS 110 and UE 120, respectively. A scheduler 244 may schedule UEs for data transmission on the downlink and/or uplink.

Example Holding Measurement Report for Unexpectedly Quick Handover

FIG. 3 is a set 300 of exemplary graphs, 310, 320, and 330, of cell measurements by a UE (e.g., UE 120, shown in FIGs. 1 and 2) that performs an unexpected handover, in accordance with certain aspects of the present disclosure. Graph 310 shows the signal-to-noise ratio (SNR) in decibels (dB) of the signal received by the UE from the UE’s serving cell. Graph 320 shows RSRP in decibel-milliwatts (dBm) of various cells, as measured by the UE. Graph 330 shows RSRQ in dBm of the various cells, as measured by the UE. At 340, the UE is camped on a cell 144 operating on E-UTRA absolute radio frequency number (EARFCN) 38950. While camping on cell 144 on EARFCN 38950, the UE measures RSRP for cell 289 on EARFCN 38400, as shown at 322, and RSRQ for cell 289 on EARFCN 38400, as shown at 332. As shown at 322, the RSRP for cell 144 on EARFCN 38400 is not poor, while the RSRQ for cell 144 on EARFCN 38400 is poor, as shown at 332. The UE keeps all of the measurements of neighboring cells in higher layers. At 350, the UE hands over to cell 144 on EARFCN 39292. Shortly after the handover, the UE measures RSRP and RSRQ for cell 144 on EARFCN 39148, as shown at 324 and 334. At 360, the UE experiences decreasing RSRP in cell 144 on EARFCN 39292 before the UE has measured cell 316 on EARFCN 40936. In response to the decreasing RSRP in cell 144 on EARFCN 39292, the UE reports measurements of the RSRP for cell 289 on EARFCN 38400 that the UE took at 322 and kept in a higher layer. There is a better HO candidate cell 316 on EARFCN 40936, but the UE has not had a chance to measure cell 316 on EARFCN 40936, as the UE hands over to the cell 289 on EARFCN 38400 so quickly. In response to the measurement report from the UE, the network causes the UE to handover to cell 289 on EARFCN 38400. However, the poor RSRQ and SNR for cell 289 on EARFCN 38400 results in the UE declaring a radio link failure at 362.

According to aspects of the present disclosure, a UE may detect an unexpected handover (HO) of the UE from a serving cell to a target cell is possible and then take steps to delay transmitting a measurement report (MR) that may lead to the unexpected HO.

In order for a UE to detect an unexpected HO (i.e., as mentioned above) , a UE may determine occurrence of a set of conditions. A first condition is that the UE determines that a target inter-frequency cell is not good and the measurement result may be not reliable. The UE may determine the target inter-frequency cell is not good and the measurement result is not reliable if all four of the following conditions are true:

1) the filtered target cell RSRP is lower than a threshold RSRP (e.g., -110dBm) ;

2) the filtered target cell RSRQ is lower than a threshold RSRQ (e.g., -15dBm) ;

3) at least a threshold period of time (e.g., 1000 ms) has passed from the last measurement of the target cell; and

4) a measurement report (MR) is triggered by the UE detecting occurrence of an A3 event (i.e., the UE determines RSRP of the target cell is a threshold amount better than an RSRP of the serving cell or RSRQ of the target cell is a threshold amount better than an RSRQ of the serving cell) .

If all of the above conditions are true, then the target inter-frequency cell may be considered by the UE to be an unexpected HO cell.

Another condition (i.e., of the set of conditions mentioned above) for the UE to detect an unexpected HO is that the UE is about to send out an MR. That is, the UE does not detect an unexpected HO if the UE is not being triggered to send an MR.

Still another condition (i.e., of the set of conditions mentioned above) for the UE to detect an unexpected HO is that serving cell conditions (e.g., RSRQ) are good enough that the UE can continue to be successfully served by that cell while the UE delays transmission of the triggered MR (i.e., the MR mentioned above) . According to aspects of the present disclosure, one purpose of this condition is for the UE to avoid being stuck being served by the serving cell if conditions are bad in that serving cell. In aspects of the present disclosure the serving cell conditions may include:

1) serving cell RSRQ > target cell RSRQ; and

2) serving cell SNR > a threshold SNR.

I.e., serving cell signal quality is better than target cell signal quality and still good enough for the UE to tolerate a delayed MR and hence, a delayed HO.

According to aspects of the present disclosure, after detecting an unexpected HO (i.e., detecting all of the conditions mentioned above) , a UE may delay (i.e., hold) transmitting an MR until after the target cell’s next measurement gap.

In aspects of the present disclosure, during the time the UE is holding (i.e., delaying) transmitting of the MR, the UE may prioritize a measurement gap for measuring new cells if there are new cells configured by the network for the UE to measure.

According to aspects of the present disclosure, while the UE is delaying transmitting the MR, if the serving cell RSRQ is no longer greater than the target cell RSRQ (i.e., serving cell RSRQ ≤ target cell RSRQ) or if the serving cell SNR is no longer greater than the threshold SNR (i.e., serving cell SNR ≤ threshold SNR) , then the UE stops delaying transmitting the MR and transmits the target cell’s MR.

In aspects of the present disclosure, once the UE has measured the target cell (i.e., the target cell’s measurement at the UE is updated) if the A3 event based on the target cell is no longer being triggered, then the UE may cancel the MR, otherwise the UE may behave according to previously known techniques (e.g., obey the previously known wireless communication specification) .

FIG. 4 is a flow diagram illustrating example operations 400 for wireless communication, in accordance with certain aspects of the present disclosure. The operations 400 may be performed, for example, by UE (e.g., such as a UE 120 in the wireless communication network 100) . Operations 400 may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor 280 of FIG. 2) . Further, the transmission and reception of signals by the UE in operations 400 may be enabled, for example, by one or more antennas (e.g., antennas 252 of FIG. 2) . In certain aspects, the transmission and/or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., controller/processor 280) obtaining and/or outputting signals.

The operations 400 may begin, at block 405, by the UE detecting one or more conditions associated with an unexpected handover (HO) of the UE from a serving cell to a target cell.

At block 410, the operations 410 continue with the UE delaying transmitting a measurement report in response to detecting the one or more conditions.

According to aspects of the present disclosure, the one or more conditions mentioned in block 405 above may include a combination of: a filtered reference signal received power (RSRP) of the target cell is lower than a threshold RSRP; a filtered reference signal received quality (RSRQ) of the target cell is lower than a threshold RSRQ; a period since a last measurement of the target cell by the UE is longer than a threshold period; and transmission of the measurement report by the UE has been triggered by at least one of: the UE determining RSRP of the target cell is a first amount better than an RSRP of the serving cell; or the UE determining RSRQ of the target cell is a second amount better than an RSRQ of the serving cell.

In aspects of the present disclosure, the threshold RSRP may be -110 decibel-milliwatts (dBm) , the threshold RSRQ may be -15 dBm, and the threshold period may be 1000 milliseconds.

According to aspects of the present disclosure, a UE performing operations 400 may receive a configuration specifying at least one of the threshold RSRP, the threshold RSRQ, or the threshold period.

In aspects of the present disclosure, the one or more conditions may include a combination of: a reference signal received quality (RSRQ) of the serving cell is greater than an RSRQ of the target cell, and a signal-to-noise-ratio (SNR) of the serving cell is greater than a threshold SNR.

According to aspects of the present disclosure, the threshold SNR may be 3 decibels (dB) .

In aspects of the present disclosure, a UE may receive a configuration specifying the threshold SNR.

According to aspects of the present disclosure, delaying transmitting the measurement report as described in block 410 may include delaying transmitting the measurement report until after occurrence of a next measurement gap for the target cell.

In aspects of the present disclosure, a UE performing operations 400 may receive, while delaying transmitting the measurement report, a configuration of an additional cell that is different from the serving cell and the target cell, and prioritize a measurement gap for the additional cell.

According to aspects of the present disclosure, a UE performing operations 400 may, while the UE is delaying transmitting the measurement report, monitor the RSRQ of the serving cell, the RSRQ of the target cell, and the SNR of the serving cell; and determine that the RSRQ of the serving cell is less than or equal to the RSRQ of the target cell or the SNR of the serving cell is less than or equal to the threshold SNR; and then transmit the measurement report in response to the determination.

In aspects of the present disclosure, a UE performing operations 400 may measure the target cell; determine reference signal received power (RSRP) of the target cell is less than a first amount better than an RSRP of the serving cell or reference signal received quality (RSRQ) of the target cell is less than a second amount better than an RSRQ of the serving cell; and cancel transmission of the measurement report.

FIG. 5 illustrates a communications device 500 that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in FIG. 4. The communications device 500 includes a processing system 502 coupled to a transceiver 508. The transceiver 508 is configured to transmit and receive signals for the communications device 500 via an antenna 510, such as the various signals as described herein. The processing system 502 may be configured to perform processing functions for the communications device 500, including processing signals received and/or to be transmitted by the communications device 500.

The processing system 502 includes a processor 504 coupled to a computer-readable medium/memory 512 via a bus 506. In certain aspects, the computer-readable medium/memory 512 is configured to store instructions (e.g., computer-executable code) that when executed by the processor 504, cause the processor 504 to perform the operations illustrated in FIG. 4, or other operations for performing the various techniques discussed herein for delaying transmission of a measurement report associated with causing an unexpectedly quick handover by a UE from a serving cell to another cell. In certain aspects, computer-readable medium/memory 512 stores code 514 for detecting one or more conditions associated with an unexpected handover (HO) of the UE from a serving cell to a target cell and code 516 for delaying transmitting a measurement report in response to detecting the one or more conditions. In certain aspects, the processor 504 has circuitry configured to implement the code stored in the computer-readable medium/memory 512. The processor 504 includes circuitry 520 for detecting one or more conditions associated with an unexpected handover (HO) of the UE from a serving cell to a target cell and circuitry 524 for delaying transmitting a measurement report in response to detecting the one or more conditions.

The methods disclosed herein comprise one or more steps or actions for achieving the methods. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.

Example Holding Measurement Report for Unexpectedly Quick Handover

Embodiment 1: A method for wireless communications performed by a user equipment (UE) , comprising detecting one or more conditions associated with an unexpected handover (HO) of the UE from a serving cell to a target cell and delaying transmitting a measurement report in response to detecting the one or more conditions.

Embodiment 2: The method of Embodiment 1, wherein the one or more conditions include a combination of: a filtered reference signal received power (RSRP) of the target cell is lower than a threshold RSRP, a filtered reference signal received quality (RSRQ) of the target cell is lower than a threshold RSRQ, a period since a last measurement of the target cell by the UE is longer than a threshold period, and transmission of the measurement report by the UE has been triggered by at least one of: the UE determining RSRP of the target cell is a first amount better than an RSRP of the serving cell, or the UE determining RSRQ of the target cell is a second amount better than an RSRQ of the serving cell.

Embodiment 3: The method of Embodiment 2, wherein: the threshold RSRP is -110 decibel-milliwatts (dBm) , the threshold RSRQ is -15 dBm, and the threshold period is 1000 milliseconds.

Embodiment 4: The method of Embodiment 2, further comprising receiving a configuration specifying at least one of the threshold RSRP, the threshold RSRQ, or the threshold period.

Embodiment 5: The method of any of Embodiments 1-4, wherein the one or more conditions include a combination of: a reference signal received quality (RSRQ) of the serving cell is greater than an RSRQ of the target cell, and a signal-to-noise-ratio (SNR) of the serving cell is greater than a threshold SNR.

Embodiment 6: The method of Embodiment 5, wherein the threshold SNR is 3 decibels (dB) .

Embodiment 7: The method of Embodiment 5, further comprising receiving a configuration specifying the threshold SNR.

Embodiment 8: The method of any of Embodiments 1-7, wherein delaying transmitting the measurement report comprises delaying transmitting the measurement report until after occurrence of a next measurement gap for the target cell.

Embodiment 9: The method of any of Embodiments 1-8, further comprising: receiving, while delaying transmitting the measurement report, a configuration of an additional cell that is different from the serving cell and the target cell; and prioritizing a measurement gap for the additional cell.

Embodiment 10: The method of Embodiment 5, further comprising while the UE is delaying transmitting the measurement report, monitoring the RSRQ of the serving cell, the RSRQ of the target cell, and the SNR of the serving cell; determining that the RSRQ of the serving cell is less than or equal to the RSRQ of the target cell or the SNR of the serving cell is less than or equal to the threshold SNR; and transmitting the measurement report in response to the determination.

Embodiment 11: The method of claim 1, further comprising: measuring the target cell; determining reference signal received power (RSRP) of the target cell is less than a first amount better than an RSRP of the serving cell or reference signal received quality (RSRQ) of the target cell is less than a second amount better than an RSRQ of the serving cell; and canceling transmission of the measurement report.

As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c) .

As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure) , ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information) , accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” Unless specifically stated otherwise, the term “some” refers to one or more. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112 (f) unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for. ”

The various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component (s) and/or module (s) , including, but not limited to a circuit, an application specific integrated circuit (ASIC) , or processor. Generally, where there are operations illustrated in figures, those operations may have corresponding counterpart means-plus-function components with similar numbering.

The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with a general purpose processor, a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device (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, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

If implemented in hardware, an example hardware configuration may comprise a processing system in a wireless node. The processing system may be implemented with a bus architecture. The bus may include any number of interconnecting buses and bridges depending on the specific application of the processing system and the overall design constraints. The bus may link together various circuits including a processor, machine-readable media, and a bus interface. The bus interface may be used to connect a network adapter, among other things, to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of a user terminal 120 (see FIG. 1) , a user interface (e.g., keypad, display, mouse, joystick, etc. ) may also be connected to the bus. The bus may also link various other circuits such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further. The processor may be implemented with one or more general-purpose and/or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry that can execute software. Those skilled in the art will recognize how best to implement the described functionality for the processing system depending on the particular application and the overall design constraints imposed on the overall system.

If implemented in software, the functions may be stored or transmitted over as one or more instructions or code on a computer readable medium. Software shall be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media include both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. The processor may be responsible for managing the bus and general processing, including the execution of software modules stored on the machine-readable storage media. A computer-readable storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. By way of example, the machine-readable media may include a transmission line, a carrier wave modulated by data, and/or a computer readable storage medium with instructions stored thereon separate from the wireless node, all of which may be accessed by the processor through the bus interface. Alternatively, or in addition, the machine-readable media, or any portion thereof, may be integrated into the processor, such as the case may be with cache and/or general register files. Examples of machine-readable storage media may include, by way of example, RAM (Random Access Memory) , flash memory, ROM (Read Only Memory) , PROM (Programmable Read-Only Memory) , EPROM (Erasable Programmable Read-Only Memory) , EEPROM (Electrically Erasable Programmable Read-Only Memory) , registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. The machine-readable media may be embodied in a computer-program product.

A software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across multiple storage media. The computer-readable media may comprise a number of software modules. The software modules include instructions that, when executed by an apparatus such as a processor, cause the processing system to perform various functions. The software modules may include a transmission module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. By way of example, a software module may be loaded into RAM from a hard drive when a triggering event occurs. During execution of the software module, the processor may load some of the instructions into cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When referring to the functionality of a software module below, it will be understood that such functionality is implemented by the processor when executing instructions from that software module.

Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared (IR) , radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , floppy disk, and

disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Thus, in some aspects computer-readable media may comprise non-transitory computer-readable media (e.g., tangible media) . In addition, for other aspects computer-readable media may comprise transitory computer-readable media (e.g., a signal) . Combinations of the above should also be included within the scope of computer-readable media.

Thus, certain aspects may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein. For example, instructions for performing the operations described herein and illustrated in FIG. 4.

Further, it should be appreciated that modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a user terminal and/or base station as applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc. ) , such that a user terminal and/or base station can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized.

It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

A method for wireless communications performed by a user equipment (UE) , comprising:

detecting one or more conditions associated with an unexpected handover (HO) of the UE from a serving cell to a target cell; and

delaying transmitting a measurement report in response to detecting the one or more conditions.
The method of claim 1, wherein the one or more conditions include a combination of:

a filtered reference signal received power (RSRP) of the target cell is lower than a threshold RSRP,

a filtered reference signal received quality (RSRQ) of the target cell is lower than a threshold RSRQ,

a period since a last measurement of the target cell by the UE is longer than a threshold period, and

transmission of the measurement report by the UE has been triggered by at least one of:

the UE determining RSRP of the target cell is a first amount better than an RSRP of the serving cell, or

the UE determining RSRQ of the target cell is a second amount better than an RSRQ of the serving cell.
The method of claim 2, wherein:

the threshold RSRP is -110 decibel-milliwatts (dBm) ,

the threshold RSRQ is -15 dBm, and

the threshold period is 1000 milliseconds.
The method of claim 2, further comprising receiving a configuration specifying at least one of the threshold RSRP, the threshold RSRQ, or the threshold period.
The method of claim 1, wherein the one or more conditions include a combination of:

a reference signal received quality (RSRQ) of the serving cell is greater than an RSRQ of the target cell, and

a signal-to-noise-ratio (SNR) of the serving cell is greater than a threshold SNR.
The method of claim 5, wherein the threshold SNR is 3 decibels (dB) .
The method of claim 5, further comprising receiving a configuration specifying the threshold SNR.
The method of claim 1, wherein delaying transmitting the measurement report comprises delaying transmitting the measurement report until after occurrence of a next measurement gap for the target cell.
The method of claim 1, further comprising:

receiving, while delaying transmitting the measurement report, a configuration of an additional cell that is different from the serving cell and the target cell; and

prioritizing a measurement gap for the additional cell.
The method of claim 5, further comprising:

while the UE is delaying transmitting the measurement report, monitoring the RSRQ of the serving cell, the RSRQ of the target cell, and the SNR of the serving cell;

determining that the RSRQ of the serving cell is less than or equal to the RSRQ of the target cell or the SNR of the serving cell is less than or equal to the threshold SNR; and

transmitting the measurement report in response to the determination.
The method of claim 1, further comprising:

measuring the target cell;

determining reference signal received power (RSRP) of the target cell is less than a first amount better than an RSRP of the serving cell or reference signal received quality (RSRQ) of the target cell is less than a second amount better than an RSRQ of the serving cell; and

canceling transmission of the measurement report.
An apparatus for wireless communications, comprising:

a processor configured to:

detect one or more conditions associated with an unexpected handover (HO) of the apparatus from a serving cell to a target cell; and

delay transmitting a measurement report in response to detecting the one or more conditions; and

a memory coupled with the processor.
The apparatus of claim 12, wherein the one or more conditions include a combination of:

a filtered reference signal received power (RSRP) of the target cell is lower than a threshold RSRP,

a filtered reference signal received quality (RSRQ) of the target cell is lower than a threshold RSRQ,

a period since a last measurement of the target cell by the apparatus is longer than a threshold period, and

transmission of the measurement report by the processor has been triggered by at least one of:

the processor determining RSRP of the target cell is a first amount better than an RSRP of the serving cell, or

the processor determining RSRQ of the target cell is a second amount better than an RSRQ of the serving cell.
The apparatus of claim 13, wherein:

the threshold RSRP is -110 decibel-milliwatts (dBm) ,

the threshold RSRQ is -15 dBm, and

the threshold period is 1000 milliseconds.
The apparatus of claim 13, wherein the processor is further configured to receive a configuration specifying at least one of the threshold RSRP, the threshold RSRQ, or the threshold period.
The apparatus of claim 12, wherein the one or more conditions include a combination of:

a reference signal received quality (RSRQ) of the serving cell is greater than an RSRQ of the target cell, and

a signal-to-noise-ratio (SNR) of the serving cell is greater than a threshold SNR.
The apparatus of claim 16, wherein the threshold SNR is 3 decibels (dB) .
The apparatus of claim 16, wherein the processor is further configured to receive a configuration specifying the threshold SNR.
The apparatus of claim 12, wherein the processor is configured to delay transmitting the measurement report by delaying transmitting the measurement report until after occurrence of a next measurement gap for the target cell.
The apparatus of claim 12, wherein the processor is further configured to:

receive, while delaying transmitting the measurement report, a configuration of an additional cell that is different from the serving cell and the target cell; and

prioritize a measurement gap for the additional cell.
The apparatus of claim 16, wherein the processor is further configured to:

while the processor is delaying transmitting the measurement report, monitor the RSRQ of the serving cell, the RSRQ of the target cell, and the SNR of the serving cell;

determine that the RSRQ of the serving cell is less than or equal to the RSRQ of the target cell or the SNR of the serving cell is less than or equal to the threshold SNR; and

transmit the measurement report in response to the determination.
The apparatus of claim 12, wherein the processor is further configured to:

measure the target cell;

determine reference signal received power (RSRP) of the target cell is less than a first amount better than an RSRP of the serving cell or reference signal received quality (RSRQ) of the target cell is less than a second amount better than an RSRQ of the serving cell; and

cancel transmission of the measurement report.