Method and processing system for wireless communication by user equipment

Abstract

The disclosure relates to a method and processing system for wireless communication by a UE. The method comprises: communicating with a serving cell over a communication link; monitoring at least one signal from the serving cell or the one or more candidate neighbor cells based at least in part on one or more measurement events configured in the one or more measurement objects; detecting the measurement event based on the monitoring, a timer configured for the measurement event in the measurement object; starting a timer based on detecting the measurement event; sending a measurement report based on the detected measurement event; receiving a conditional handover command for handover of the UE to a candidate target cell of the candidate neighbor cells, comprising one or more trigger conditions for performing conditional handover to the candidate target cell; and switching the command to stop the timer based on the condition, the stop timer further comprising: receiving an indication of a threshold number of synchronization indications; and stopping the timer based on the received indication of the threshold number of synchronization indications.

Description

[0001] This application is a divisional application of the Chinese invention patent application with application date of August 18, 2020 and application number 202080057654.1.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Application No. 16 / 995,512, filed on August 17, 2020, which claims priority to and the benefit of U.S. Provisional Application No. 62 / 890,457, filed on August 22, 2019, both of which are hereby assigned to the assignee of the present application and are hereby expressly incorporated by reference in their entireties into this application, as if fully set forth below, and for all applicable purposes. Technical Field

[0004] Aspects of the present disclosure relate to wireless communications and, more particularly, to techniques for handling a radio link failure timer in the presence of a conditional handover command. Background Art

[0005] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcast, 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.

[0006] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at municipal, national, regional, and even global levels. 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 aims to better support mobile broadband Internet access by increasing spectrum efficiency, reducing costs, improving services, leveraging new spectrum, and better integrating with other open standards using OFDMA with cyclic prefix (CP) on downlink (DL) and uplink (UL). To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0007] However, as the demand for mobile broadband access continues to increase, further improvements to NR and LTE technologies are needed. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that adopt these technologies. Summary of the invention

[0008] The systems, methods, and devices of the present disclosure each have several aspects, no single aspect of which is solely responsible for its desirable attributes. Without limiting the scope of the present disclosure as expressed by the appended claims, some features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled "Detailed Description of the Invention," one will understand how the features of the present disclosure provide advantages including improved handling of a radio link failure timer in the presence of a conditional handover command.

[0009] Certain aspects provide a method for wireless communication by a user equipment (UE). The method generally includes: communicating with a serving cell via a communication link; monitoring at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detecting one or more measurement events based on the monitoring, wherein a timer is configured for the one or more measurement events in the one or more measurement objects; starting a timer based on the detection of the one or more measurement events; sending a measurement report based on the detected one or more measurement events; receiving a conditional handover command for handing the UE to a candidate target cell in the one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing the conditional handover to the candidate target cell; and stopping the timer based on the received conditional handover command.

[0010] Certain aspects provide an apparatus for wireless communication by a user equipment (UE). The apparatus generally includes at least one processor configured to: communicate with a serving cell via a communication link; monitor at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detect one or more measurement events based on monitoring, wherein a timer is configured for one or more measurement events in one or more measurement objects; start a timer based on detecting one or more measurement events; send a measurement report based on the detected one or more measurement events; receive a conditional handover command for handing the UE to a candidate target cell in one or more candidate neighboring cells, wherein the conditional handover command includes one or more trigger conditions for performing a conditional handover to the candidate target cell; and stop the timer based on the received conditional handover command. The apparatus generally also includes a memory coupled to the at least one processor.

[0011] Certain aspects provide an apparatus for wireless communication by a user equipment (UE). The apparatus generally includes: a component for communicating with a serving cell via a communication link; a component for monitoring at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; a component for detecting one or more measurement events based on monitoring, wherein a timer is configured for one or more measurement events in one or more measurement objects; a component for starting a timer based on detecting one or more measurement events; a component for sending a measurement report based on the detected one or more measurement events; a component for receiving a conditional handover command for handing the UE to a candidate target cell in one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing conditional handover to the candidate target cell; and a component for stopping the timer based on the received conditional handover command.

[0012] Certain aspects provide a non-transitory computer-readable medium for wireless communication by a user equipment (UE). The apparatus generally includes instructions that, when executed by at least one processor, cause the at least one processor to: communicate with a serving cell via a communication link; monitor at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detect one or more measurement events based on monitoring, wherein a timer is configured for one or more measurement events in one or more measurement objects; start a timer based on detecting the one or more measurement events; send a measurement report based on the detected one or more measurement events; receive a conditional handover command for handing the UE to a candidate target cell in one or more candidate neighboring cells, wherein the conditional handover command includes one or more trigger conditions for performing a conditional handover to the candidate target cell; and stop the timer based on the received conditional handover command.

[0013] Certain aspects provide a method for wireless communication by a user equipment (UE). The method generally includes: receiving a conditional handover command from a serving cell for handing over the UE to a target neighboring cell, wherein the conditional handover command includes one or more trigger conditions for performing a handover to a candidate target cell; monitoring one or more first signals from the candidate target cell for the one or more trigger conditions; and performing one of the following: stopping a timer based on performing the conditional handover to the target candidate cell; or detecting that the timer has expired while monitoring the one or more first signals from the candidate target cell for the one or more trigger conditions.

[0014] Certain aspects provide an apparatus for wireless communication by a user equipment (UE). The apparatus generally includes at least one processor configured to: receive a conditional handover command from a serving cell for handing over the UE to a target neighboring cell, wherein the conditional handover command includes one or more trigger conditions for performing a handover to a candidate target cell; monitor one or more first signals from the candidate target cell for the one or more trigger conditions; and perform one of the following: stop a timer based on performing a conditional handover to the target candidate cell; or detect that a timer has expired when monitoring one or more first signals from the candidate target cell for the one or more trigger conditions. The apparatus generally also includes a memory coupled to the at least one processor.

[0015] Certain aspects provide an apparatus for wireless communication by a user equipment (UE). The apparatus generally includes: a component for receiving a conditional handover command for handing over the UE to a target neighboring cell from a serving cell, wherein the conditional handover command includes one or more trigger conditions for performing a handover to a candidate target cell; a component for monitoring one or more first signals from the candidate target cell for the one or more trigger conditions; and a component for performing one of the following operations: stopping a timer based on performing the conditional handover to the target candidate cell; or detecting that the timer has expired while monitoring the one or more first signals from the candidate target cell for the one or more trigger conditions.

[0016] Certain aspects provide a non-transitory computer-readable medium for wireless communication by a user equipment (UE). The apparatus generally includes instructions that, when executed by at least one processor, cause the at least one processor to: receive a conditional handover command from a serving cell for handing over the UE to a target neighboring cell, wherein the conditional handover command includes one or more trigger conditions for performing a handover to a candidate target cell; monitor one or more first signals from the candidate target cell for the one or more trigger conditions; and perform one of the following: stop a timer based on performing a conditional handover to the target candidate cell; or detect that a timer has expired while monitoring the one or more first signals from the candidate target cell for the one or more trigger conditions.

[0017] Certain aspects provide a method for wireless communication by a user equipment (UE), comprising: communicating with a serving cell via a communication link; monitoring at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detecting the one or more measurement events based on the monitoring, wherein a timer is configured for one or more measurement events in the one or more measurement objects; starting the timer based on detecting the one or more measurement events; sending a measurement report based on the detected one or more measurement events; receiving a conditional switching command for switching the UE to a candidate target cell in the one or more candidate neighboring cells, wherein the conditional switching command includes one or more triggering conditions for performing conditional switching to the candidate target cell; and stopping the timer based on the received conditional switching command, wherein stopping the timer also includes: receiving an indication of a threshold number of synchronization indications; and stopping the timer based on the received indication of a threshold number of synchronization indications.

[0018] Certain aspects provide a method for wireless communication by a user equipment (UE), comprising: communicating with a serving cell via a communication link; monitoring at least one of one or more signals from the serving cell or at least one of one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detecting the one or more measurement events based on the monitoring, wherein a timer is configured for one or more measurement events in the one or more measurement objects; starting the timer based on detecting the one or more measurement events; sending a measurement report based on the detected one or more measurement events; receiving a conditional switching command for switching the UE to a candidate target cell in the one or more candidate neighboring cells, wherein the conditional switching command includes one or more triggering conditions for performing conditional switching to the candidate target cell; and stopping the timer based on the received conditional switching command, wherein stopping the timer also includes: initiating a connection reconstruction process to reconstruct the communication link; and stopping the timer based on the initiated connection reconstruction process.

[0019] Certain aspects provide a method for wireless communication by a user equipment (UE), comprising: communicating with a serving cell via a communication link; monitoring one or more signals from the serving cell or at least one of one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detecting the one or more measurement events based on the monitoring, wherein a timer is configured for one or more measurement events in the one or more measurement objects; starting the timer based on detecting the one or more measurement events; sending a measurement report based on the detected one or more measurement events; receiving a conditional switching command for switching the UE to a candidate target cell in the one or more candidate neighboring cells, wherein the conditional switching command includes one or more triggering conditions for performing conditional switching to the candidate target cell; and stopping the timer based on the received conditional switching command, wherein stopping the timer also includes: determining that a second timer expires; and stopping the timer based on the expiration of the second timer.

[0020] Certain aspects provide a processing system for wireless communication by a user equipment (UE), comprising: one or more processors, individually or collectively configured to execute instructions stored on one or more memories, and causing the UE to: communicate with a serving cell via a communication link; monitor one or more signals from the serving cell or at least one of one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detect the one or more measurement events based on the monitoring, wherein a timer is configured for one or more measurement events in the one or more measurement objects; start the timer based on detecting the one or more measurement events; send a measurement report based on the detected one or more measurement events; receive a conditional handover command for handing the UE to a candidate target cell in the one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing conditional handover to the candidate target cell; and stop the timer based on the received conditional handover command, wherein, in order to stop the timer, the one or more processors are further configured to: receive an indication of a threshold number of synchronization indications; and stop the timer based on the received indication of the threshold number of synchronization indications.

[0021] Certain aspects provide a processing system for wireless communication by a user equipment (UE), comprising: one or more processors, individually or collectively configured to execute instructions stored on one or more memories, and causing the UE to: communicate with a serving cell via a communication link; monitor one or more signals from the serving cell or at least one of one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detect the one or more measurement events based on the monitoring, wherein a timer is configured for one or more measurement events in the one or more measurement objects; start the timer based on detecting the one or more measurement events; send a measurement report based on the detected one or more measurement events; receive a conditional handover command for switching the UE to a candidate target cell in the one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing conditional handover to the candidate target cell; and stop the timer based on the received conditional handover command, wherein, in order to stop the timer, the one or more processors are further configured to: initiate a connection reestablishment process to reestablish the communication link; and stop the timer based on the initiated connection reestablishment process.

[0022] Certain aspects provide a processing system for wireless communication by a user equipment (UE), comprising: one or more processors, individually or collectively configured to execute instructions stored on one or more memories, and causing the UE to: communicate with a serving cell via a communication link; monitor one or more signals from the serving cell or at least one of one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detect the one or more measurement events based on the monitoring, wherein a timer is configured for one or more measurement events in the one or more measurement objects; start the timer based on detecting the one or more measurement events; send a measurement report based on the detected one or more measurement events; receive a conditional handover command for switching the UE to a candidate target cell in the one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing conditional handover to the candidate target cell; and stop the timer based on the received conditional handover command, wherein, in order to stop the timer, the one or more processors are further configured to: determine that a second timer expires; and stop the timer based on the expiration of the second timer.

[0023] To achieve the aforementioned and related purposes, one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain illustrative features of one or more aspects. However, these features are only indicative of some of the various ways in which the principles of the various aspects can be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to be able to understand the above-mentioned features of the present disclosure in detail, a more specific description briefly summarized above may be obtained by reference to various aspects, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate certain typical aspects of the present disclosure and are therefore not to be considered as limiting the scope thereof, as the description may admit to other equally effective aspects.

[0025] Figure 1 is a block diagram conceptually illustrating an example telecommunications system in accordance with certain aspects of the present disclosure.

[0026] Figure 2 is a block diagram conceptually illustrating designs of example base stations (BSs) and user equipment (UEs) in accordance with certain aspects of the present disclosure.

[0027] Figure 3 An example of a decision flow for an early RLF declaration in accordance with aspects of the present disclosure is shown.

[0028] Figure 4 is a flow diagram illustrating example operations for wireless communications by a UE in accordance with certain aspects of the present disclosure.

[0029] Figure 5 A call flow diagram illustrating example operations for handling a situation where no conditional handover configuration is active in the UE before the RLF timer is triggered, in accordance with certain aspects of the present disclosure.

[0030] Figure 6 is a flow diagram illustrating example operations for wireless communications by a UE in accordance with certain aspects of the present disclosure.

[0031] Figure 7 A call flow diagram illustrating example operations for handling a situation where a conditional handover configuration is active in a UE before a RLF timer is triggered, in accordance with certain aspects of the present disclosure.

[0032] Figure 8 A communications device is shown that may include various components configured to perform operations of the techniques disclosed herein according to aspects of the present disclosure.

[0033] Fig. 9 A communications device is shown that may include various components configured to perform operations of the techniques disclosed herein according to aspects of the present disclosure.

[0034] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements in the drawings. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation. DETAILED DESCRIPTION

[0035] Various aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for handling a radio link failure timer in the presence of a conditional handover command. For example, a conditional handover is a type of handover in which a serving cell provides a handover command to a UE that includes one or more trigger conditions for autonomously initiating a handover to a candidate neighboring cell. However, it is currently unspecified how conditional handovers should interact with a radio link failure (RLF) timer. Therefore, various aspects of the present disclosure provide techniques for handling an RLF timer (e.g., start, stop, expiration behavior) in the presence of a conditional handover command.

[0036] As described above, the following description provides an example of processing a radio link failure timer in the presence of a conditional handover command in a communication system, and does not limit the scope, applicability or examples set forth in the claims. Without departing from the scope of the present disclosure, the functions and arrangements of the elements discussed may be changed. Various examples may appropriately omit, replace or add various programs or components. For example, the described method may be performed in an order different from that described, and various steps may be added, omitted or combined. In addition, the features described with respect to some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover such a device or method, which is practiced using other structures, functions or structures and functions other than or different from the various aspects of the present 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 the claims. The word "exemplary" is used here to mean "used as an example, instance or illustration". Any aspect described as "exemplary" herein is not necessarily interpreted as taking precedence over or superior to other aspects.

[0037] Typically, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific radio access technology (RAT) and can operate on one or more frequencies. RAT can also be referred to as radio technology, air interface, etc. Frequency can also be referred to as carrier, subcarrier, channel, tone, subband, etc. Each frequency can support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, 5G NR RAT networks may be deployed.

[0038] Figure 1 An example wireless communication network 100 is shown in which aspects of the present disclosure may be performed. For example, the wireless communication network 100 may be a NR system (e.g., a 5G NR network).

[0039] like Figure 1 As shown, the wireless communication network 100 may include multiple base stations (BSs) 110a-z (each base station is also individually referred to as BS 110 or collectively referred to as multiple BSs 110 in this document) and other network entities. BS 110 can provide communication coverage for a specific geographic area (sometimes referred to as a "cell"), which can be fixed or can move depending on the location of the mobile BS 110. In some examples, BS 110 can be interconnected with each other and / or to one or more other BSs or network nodes (not shown) in the wireless communication network 100 through various types of backhaul interfaces (e.g., direct physical connections, wireless connections, virtual networks, etc.) using any suitable transmission network. Figure 1 In the example shown, BSs 110a, 110b, and 110c may be macro BSs of macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS of pico cell 102x. BSs 110y and 110z may be femto BSs of femto cells 102y and 102z, respectively. A BS may support one or more cells. BS 110 communicates with user equipment (UE) 120a-y (each user equipment is also referred to herein individually as UE 120 or collectively as a plurality of UEs 120) in wireless communication network 100. UEs 120 (e.g., 120x, 120y, etc.) may be dispersed throughout wireless communication network 100, and each UE 120 may be fixed or mobile.

[0040] According to certain aspects, BS 110 and / or UE 120 may be configured to handle a radio link failure (RLF) timer in the presence of a conditional handover command, as described below. Figure 1 As shown, UE 120a includes RLF manager 122. According to aspects of the present disclosure, in some cases, RLF manager 122 may be configured to perform Figure 4-Figure 7 One or more of the operations shown in and other operations described herein for handling a radio link failure timer in the presence of a conditional handover command.

[0041] The wireless communication network 100 may also include a relay station (e.g., relay station 110r), also referred to as a relay or the like, which receives transmissions of data and / or other information from an upstream station (e.g., BS 110a or UE 120r) and sends transmissions of data and / or other information to a downstream station (e.g., UE 120 or BS 110), or relays transmissions between UEs 120 to facilitate communication between devices.

[0042] A network controller 130 may couple to a set of BSs 110 and provide coordination and control for these BSs 110. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with each other (eg, directly or indirectly) via a wireless or wired backhaul.

[0043] Figure 2 Example components of BS 110a and UE 120a are shown (eg, in Figure 1 In the wireless communication network 100), which can be used to implement various aspects of the present disclosure.

[0044] At BS 110a, 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 a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical hybrid ARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), a group common PDCCH (GC PDCCH), etc. The data may be for a physical downlink shared channel (PDSCH), etc. The processor 220 may process (e.g., encode and symbol map) the data and the control information to obtain data symbols and control symbols, respectively. The transmit processor 220 may also generate reference symbols, such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a cell-specific reference signal (CRS). If applicable, a transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​the data symbols, control symbols, and / or reference symbols, and may provide an output symbol stream to a modulator (MOD) 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. The downlink signals from modulators 232a-232t may be transmitted via antennas 234a-234t, respectively.

[0045] At UE 120a, antennas 252a-252r may receive downlink signals from BS 110a and may provide received signals to demodulators (DEMODs) in transceivers 254a-254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a corresponding 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 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 UE 120a to a data sink 260, and provide decoded control information to a controller / processor 280.

[0046] On the uplink, at the UE 120a, a transmit processor 264 may receive and process data from a data source 262 (e.g., for a physical uplink shared channel (PUSCH)) and control information from a controller / processor 280 (e.g., for a physical uplink control channel (PUCCH)). The transmit processor 264 may also generate reference symbols for reference signals (e.g., a 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 a demodulator in the transceiver 254a-254r (e.g., for SC-FDM, etc.), and transmitted to the BS 110a. At the BS 110a, the uplink signal from the UE 120a may be received by the antenna 234, processed by the modulator 232, detected by the MIMO detector 236 (if applicable), and further processed by the receive processor 238 to obtain decoded data and control information transmitted by the UE 120a. The receive processor 238 may provide decoded data to a data sink 239 and decoded control information to a controller / processor 240 .

[0047] Memories 242 and 282 may store data and program codes for BS 110a and UE 120a, respectively. A scheduler 244 may schedule UEs for data transmission on the downlink and / or uplink.

[0048] The controller / processor 280 and / or other processors and modules at the UE 120a may perform or direct the execution of the processes described herein for techniques for handling a radio link failure timer in the presence of a conditional handover command. Figure 2As shown, according to various aspects described herein, the controller / processor 280 of the UE 120a includes an RLF manager 281, which may be configured to perform Figure 4-Figure 7 The operations shown in one or more of UE 120a and other operations described herein for handling a radio link failure timer in the presence of a conditional handover command. Although shown at the controller / processor, other components of UE 120a and BS 110a may be used to perform the operations described herein.

[0049] Example Early Radio Link Failure Detection

[0050] In some cases, the radio link between the UE 120 and the base station 110 may deteriorate to the extent that effective communication between the UE 120 and the base station 110 is terminated. In this case, the base station may discard the context information of the UE, and the UE may perform a radio link failure (RLF) procedure. The RLF procedure may include establishing a new radio connection with a neighboring base station. The new neighboring base station may attempt to obtain context information from the previous serving station. However, if the previous base station has discarded the context information, the request of the neighboring base station may fail, and a delay may be caused when the new base station and the UE re-establish a new context. Therefore, in order to avoid such delays, an early RLF detection mechanism is introduced to allow the UE to detect that the RLF is imminent and switch to the neighboring base station before the RLF occurs.

[0051] Figure 3 An example of a decision flow 300 for early RLF declaration according to aspects of the present disclosure is shown. The decision flow 300 may be represented as shown in FIG. Figure 1-Figure 2 The steps performed by UE 120 are described.

[0052] At step 305, UE 120 may monitor channel conditions of the serving cell and one or more neighboring cells. For example, UE 120 may receive a measurement configuration from base station 110 as part of an RRC configuration message indicating a set of neighboring cells to monitor. During monitoring, UE 120 may measure values ​​of the serving cell and one or more cells from the set of neighboring cells, the values ​​corresponding to one or more channel parameters of the cells.

[0053] At step 310, the UE may identify a measurement report trigger, such as a measurement report message (MRM) triggering event that has occurred or has been triggered. In some examples, the measurement report trigger is an A1, A2, A3, A4, A5, B1, or B2 event in the measurement configuration of the UE.

[0054] For example, in some cases, a first measurement report trigger (e.g., A1) may occur when the serving cell becomes better than a threshold; a second measurement report trigger (e.g., A2) may occur when the serving cell becomes worse than a threshold; a third measurement report trigger (e.g., A3) may occur when the neighboring cell becomes better than the primary serving cell by an offset value; a second measurement report trigger (e.g., A4) may occur when the neighboring cell becomes better than the threshold; a fifth measurement report trigger (e.g., A5) may occur when the primary serving cell becomes worse than the threshold and the neighboring cell is simultaneously better than another (e.g., higher) threshold; a sixth measurement report trigger (e.g., A6) may occur when the neighboring cell becomes better than the secondary serving cell by an offset value; a seventh measurement report trigger (e.g., B1) may occur when a neighboring cell using a different radio access technology (RAT) becomes better than a threshold; and an eighth measurement report trigger (e.g., B2) may occur when the primary serving cell becomes worse than a threshold and the inter-RAT neighboring cell becomes better than another threshold.

[0055] In some examples, if UE 120 identifies a measurement report trigger, then at step 315 UE 120 may start a first RLF timer (eg, T310 timer) based on the MRM trigger.

[0056] In step 316, UE 120 may send an UL message, such as an MRM or other UL radio link signaling message, based on the MRM trigger. The RLF timer may be used in conjunction with other timers for RLF declaration or may be used independently. For example, in some cases, the T310 timer may be triggered based on detection of a PHY layer problem at the serving cell (e.g., when the number of out-of-sync indications reaches a threshold). The T312 timer may be another example of a timer that may be used in conjunction with the RLF timer. For example, the T312 timer may be turned on / triggered when T310 is running, and the MRM is sent to the serving cell based on a measurement report trigger / identifier (e.g., an A1, A2, A3, A4, A5, B1, or B2 event identifier) ​​for which T312 has been configured. In some cases, since the T310 timer may be relatively long, the T312 timer may be used to facilitate faster RLF recovery, for example, by allowing the T310 timer to expire earlier.

[0057] At step 330, UE 120 may detect whether radio link conditions indicative of RLF have been met, the determination being prompted by the identified measurement report trigger. For example, the determination may be based on a determination of whether an RLC layer ACK for an UL message has been received, such as an RLC layer ACK in response to one or more MRMs or other UL radio link signaling messages. In various examples, if an RLC layer ACK is not received, this may be an indication that channel conditions of the serving cell have significantly deteriorated.

[0058] Even if an RLC layer ACK is received, or in some cases, if no RLC layer ACK is received, the UE 120 may determine that RLF is imminent. For example, at step 330, the UE 120 may wait for a handover command based on UL radio link signaling message transmission. In some cases, even if the UE 120 receives an RLC layer ACK (confirming that the serving cell receives the MRM), the UE 120 may not receive a subsequent handover command based on the low channel quality of the serving cell.

[0059] If a handover command is received, the UE 115 may stop the T312 timer and perform the handover as instructed at step 335. In addition, the T312 timer may be stopped based on other criteria, such as when an N311 continuous synchronization indication is received, when a connection reestablishment procedure is initiated, or when a T310 timer expires.

[0060] However, if a handover command is not received at step 335, then UE 120 may determine that the RLF timer has expired at step 340. Such absence of a handover command and expiration of the RLF timer may satisfy a radio link condition indicating RLF.

[0061] As an additional or alternative method of determining that an RLF is imminent, if an RLC layer ACK for an UL message, such as an RLC layer ACK in response to an MRM message or other UL radio link signaling message, is not received at step 320, the UE 120 may increment a counter and then determine whether the counter for the number of RLC layer ACKs exceeds a threshold. If the threshold is not exceeded, at step 316, the UE 120 may retransmit the UL message and wait for another RLC layer ACK. However, at step 325, if the number of UL messages sent without an RLC layer ACK exceeds a threshold, the UE 120 may determine that the radio link conditions for an upcoming RLF are met. In some examples, the radio link conditions may also be indicated based on a service type. For example, the length of the RLF timer or other aspects of the radio link condition processing may depend on whether the service type is a VoLTE service type (or another service type with a QoS standard).

[0062] Some examples may include step 345, where once the UE 120 has detected a condition indicative of RLF (e.g., based on an RLF timer or an RLC layer ACK threshold); the UE 120 may optionally verify that a channel comparison condition has been met based on a serving cell channel parameter and a target cell channel parameter. In some examples, verifying that the channel comparison condition has been met includes: determining that the serving cell channel parameter is below a first threshold, and determining that the target cell channel parameter is above a second threshold. In some examples, verifying that the channel comparison condition has been met includes: determining that the target cell channel parameter exceeds the serving cell channel parameter by an offset value. The verification of the channel comparison condition may be used to ensure that during the process of determining that RLF is imminent, channel conditions have not recovered in the serving cell, or have not deteriorated in the target cell.

[0063] At step 350, if the UE 120 has detected a condition indicating RLF, and in some examples, if the channel comparison condition is also met, the UE 120 may initiate an RLF procedure based at least in part on the detected condition indicating RLF and, where applicable, on verification that the channel comparison condition has been met. For example, at step 350, the UE may declare RLF. In some examples, after initiating the RLF procedure, such as after a declared RLF, the UE 120 may then initiate a connection reestablishment procedure to establish a connection to the target cell. In some cases, this may be an early RLF declaration, which may mitigate any service disruption associated with the transition to the new cell. For example, it may enable the target cell to retrieve the context of the UE 120 before the serving cell discards the context.

[0064] Conditional handover and radio link failure timer interaction

[0065] As described above, the UE may use one or more timers for radio link failure (RLF) detection and recovery. Such timers may include a T310 timer and a T312 timer. For example, in some cases, the UE may communicate with a serving cell via a communication link. In some cases, the UE may trigger the T310 timer based on detecting a PHY layer problem (e.g., the communication link is deteriorating) in the serving cell (such as the number of received out-of-sync indications reaching a threshold). In some cases, the UE may receive configuration information for one or more measurement objects, the configuration information including an indication of one or more measurement event triggers configured for the serving cell. In addition, timers such as the T312 timer may be configured for one or more measurement event triggers in one or more measurement objects.

[0066] According to various aspects, the UE may perform monitoring for one or more measurement event triggers in one or more measurement objects, and upon detecting one or more measurement event triggers, and if the T310 timer is already running, the UE may trigger the T312 timer for the measurement event for which T312 has been configured. In some cases, the UE may detect one or more event triggers based on measurements performed on one or more signals from a serving cell. Upon detecting one or more measurement event triggers, the UE may send a measurement report. In some cases, the one or more signals may include one or more reference signals, such as one or more channel state information reference signals (CSI-RS) and / or one or more synchronization signal blocks (SSBs).

[0067] According to various aspects, the T312 timer may be used to facilitate faster RLF recovery by allowing early termination of the T310 timer. For example, in some cases, if the UE fails to receive a response to a sent measurement report before the T312 timer expires, the UE may declare RLF and stop the T310 timer. Thereafter, after the T312 timer expires, the UE may take one or more actions, such as transitioning to a radio resource control (RRC) idle mode or initiating a connection reestablishment procedure to connect to a neighboring cell.

[0068] In some cases, the UE may stop the T312 timer before the T312 timer expires. For example, the UE may determine to stop the T312 timer before the T312 timer expires when (1) the UE receives an N311 continuous synchronization indication from a lower layer, (2) the UE receives a handover command that triggers a handover procedure to a neighboring cell, (3) when a connection reestablishment procedure is initiated, or (4) when the T310 timer expires.

[0069] According to various aspects, the RLF timer discussed above has traditionally been associated with normal handover. However, the concept of conditional handover has recently been introduced. Conditional handover is a type of handover in which the serving cell provides a handover command to the UE, which includes one or more trigger conditions for autonomously initiating a handover to a candidate neighboring cell. For example, upon receiving the conditional handover command, the UE may begin monitoring one or more candidate neighboring cells. If the UE detects that one or more trigger conditions have been met for a candidate neighboring cell, the UE may autonomously initiate a handover to the neighboring cell without further assistance from the serving cell.

[0070] However, there is currently no specification for how conditional switching should interact with the RLF timer discussed above. Therefore, aspects of the present disclosure provide techniques for handling RLF timers (e.g., start, stop, expiration behavior) in the presence of a conditional switching command. In some cases, the techniques for handling RLF timers in the presence of conditional switching may depend on, for example, whether the UE has been configured with conditional switching when the RLF timer is triggered. Therefore, aspects of the present disclosure provide techniques for handling situations where no conditional switching configuration is active in the UE before the RLF timer is triggered. In addition, aspects of the present disclosure provide techniques for handling situations where a conditional switching configuration is active in the UE before the RLF timer is triggered.

[0071] For example, in some cases, even when a measurement report is triggered for configuring a conditional handover (e.g., providing information to a serving cell to configure a conditional handover), an RLF timer, such as a T312 timer, may be started similar to LTE legacy behavior (e.g., when a measurement report for a measurement identity for which a T312 timer has been configured is triggered while a T310 timer is running). Additionally, in some cases, an RLF timer may be started even when a conditional handover has been configured at the UE and before the conditional handover is performed by the UE, for example, while the UE is monitoring a target neighboring cell identified by the conditional handover. According to various aspects, in this case, a measurement report may be triggered on the source cell for a measurement identity for which a T312 timer has been configured while a T310 timer is running.

[0072] According to various aspects, in some cases, the RLF timer may be stopped. For example, in some cases, the UE may stop the RLF timer upon receiving a conditional handover radio resource control (RRC) reconfiguration message. Additionally, in some cases, for example, if the UE is configured by a conditional handover command to monitor one or more trigger conditions corresponding to a candidate neighboring cell before the RLF timer is turned on, the RLF timer may be stopped when the conditional handover command is executed to handover the UE to the candidate neighboring cell.

[0073] In some cases, the RLF timer may expire. According to various aspects, in this case, upon expiration of the RLF timer, the UE may follow the conventional LTE T312 timer expiration behavior even when conditional handover is configured but not performed. For example, if the RLF timer expires and if security is not activated, the UE may take one or more actions, such as entering an idle mode (e.g., RRC_IDLE) or may initiate a connection reestablishment procedure to establish a communication link with a candidate neighboring cell.

[0074] Figure 4 4 is a flow chart illustrating example operations 400 for wireless communications in accordance with certain aspects of the present disclosure. Operations 400 may be performed, for example, by a UE (e.g., UE 120a in wireless communication network 100) for handling a situation where no conditional handover configuration is active in the UE before the RLF timer is triggered. Operations 400 may be implemented as a process in one or more processors (e.g., Figure 2 In addition, the communication may be performed, for example, via one or more antennas (e.g., Figure 2 The antenna 252 of the UE is used to implement the transmission and reception of signals by the UE in operation 400. In some aspects, the transmission and / or reception of signals by the UE may be implemented via a bus interface of one or more processors (eg, the controller / processor 280) that obtain and / or output signals.

[0075] Operations 400 may begin at 405 by communicating with a serving cell over a communication link.

[0076] At 410, based at least in part on one or more measurement events configured in one or more measurement objects, the UE monitors at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells. For example, in some cases, the UE may receive configuration information including one or more measurement objects, the configuration information indicating one or more measurement events or measurement event triggers. In some cases, the one or more measurement events may include, for example, one or more of the A1, A2, A3, A4, A5, B1, or B2 event identifiers discussed above. In addition, in some cases, one or more measurement objects may be configured by the serving cell to report at least one of a normal handover (HO), a make-before-break HO, a random access channel (RACH)-free HO, or a conditional HO to one or more candidate neighboring cells.

[0077] At 415, the UE detects one or more measurement events based on monitoring, wherein a timer is configured for the one or more measurement events in the one or more measurement objects. In some cases, as discussed above, the timer may be a T312 timer.

[0078] At 420, the UE starts a timer based on detecting one or more measurement events. In some cases, the UE may start a timer when another timer (such as a T310 timer) is already running. For example, as described above, in response to detecting that the signal quality associated with the communication link is deteriorating, the UE may have previously started the T310 timer.

[0079] At 425, the UE sends a measurement report based on the detected one or more measurement events. In some cases, the measurement report may include parameters indicating channel / signal quality associated with the serving cell (eg, communication link) and one or more candidate neighbor cells.

[0080] At 430, the UE receives a conditional handover command for handing over the UE to a candidate target cell of the one or more candidate neighboring cells. In some cases, the conditional handover command includes one or more triggering conditions for performing the conditional handover to the candidate neighboring cell.

[0081] At 435, the UE stops the timer based on the received conditional handover command.

[0082] Additionally, in some cases, stopping the timer may also include receiving an indication of a threshold number of synchronization indications. According to various aspects, the UE may then stop the timer based on the received indication of the threshold number of synchronization indications.

[0083] In addition, in some cases, stopping the timer may also include initiating a handover procedure to switch the UE to the candidate target cell. In some cases, initiating the handover procedure may be based on a handover command instructing the UE to switch to the candidate target cell. In response, the UE may stop the timer based on the initiated handover procedure.

[0084] Additionally, in some cases, stopping the timer may also include initiating a connection reestablishment procedure to reestablish the communication link. According to various aspects, in response, the UE may stop the timer based on the initiated connection reestablishment procedure.

[0085] Additionally, in some cases, stopping the timer may include determining that a second timer expires. In some cases, the second timer may include a T310 timer. According to various aspects, based on the expiration of the T310 timer, the UE may stop the T312 timer.

[0086] Figure 5 A call flow diagram illustrating example operations for handling a situation where no conditional handover configuration is active in the UE before the RLF timer is triggered is shown in accordance with certain aspects presented herein.

[0087] According to various aspects, although Figure 51, but UE 502 may communicate with serving cell 504 (e.g., source gNB) via a communication link. In some cases, as discussed above, UE 502 and serving cell 504 may include UE 120 and BS 110, respectively. At some point in time, UE 502 may detect that signal quality associated with the communication link is deteriorating and may start a T310 timer, as shown at 520. According to various aspects, after starting the T310 timer at 520, UE 502 may monitor at least one of one or more signals from serving cell 504 or one or more signals from one or more candidate neighbor cells (e.g., candidate neighbor cell 506 and candidate neighbor cell 508, also referred to as candidate target cells) based at least in part on one or more configured measurement events in one or more received measurement objects. Based on the monitoring, at 522, UE 502 may detect one or more measurement events (e.g., one or more measurement event triggers). In some cases, a second timer, such as a T312 timer, may be configured for one or more measurement events in one or more measurement objects.

[0088] According to aspects, the UE may start a T312 timer at 524 and send a measurement report at 526 based on detecting one or more measurement events.

[0089] Thereafter, as shown in 528 and 529, based on the measurement report, the serving cell 504 may prepare a conditional handover command for handing the UE to a candidate target cell of one or more candidate neighboring cells, such as the candidate neighboring cell 506 or the candidate neighboring cell 508. In some cases, preparing the conditional handover command may include, for example, preparing the candidate target cell (e.g., as shown in 528 and 529) for handover by sending UE context information to the candidate cell. In some cases, the conditional handover command includes one or more triggering conditions for performing the conditional handover to the candidate neighboring cell. In addition, in some cases, the conditional handover command may include information for accessing the candidate target cell.

[0090] Thereafter, at 530, serving cell 504 may send a conditional handover command to UE 502. In some cases, the conditional handover command may be sent / received in an RRC reconfiguration message.

[0091] Accordingly, in response to receiving the conditional handover command, the UE may stop the T312 timer and the T310 timer at 532. In addition, the UE may stop the T312 timer in other situations, such as (1) receiving an indication of a threshold number of synchronization indications, (2) receiving a handover command and initiating a handover procedure to handover the UE to a candidate target cell, (3) initiating a connection reestablishment procedure to reestablish a communication link, or (4) when the T310 timer expires.

[0092] According to various aspects, Figure 5 The operations shown in FIG. 3 show that the T312 timer can be started due to a measurement event trigger for a measurement object configured with T312 and configured for normal HO reporting or conditional handover cell reporting. According to various aspects, if another measurement report is triggered for any T312-configured measurement object while T312 is running, the T312 timer can be reset.

[0093] Figure 6 6 is a flow chart illustrating example operations 600 for wireless communication in accordance with certain aspects of the present disclosure. Operations 600 may be performed, for example, by a UE (e.g., UE 120a in wireless communication network 100) to handle a situation where a conditional handover configuration is active in the UE before the RLF timer is triggered. Operations 600 may be implemented as a processor (e.g., Figure 2 In addition, in operation 600, the signal may be transmitted to the receiver via one or more antennas (e.g., Figure 2 The antenna 252 of the UE implements the transmission and reception of signals by the UE. In some aspects, the transmission and / or reception of signals by the UE can be implemented via a bus interface of one or more processors (eg, the controller / processor 280) that obtain and / or output signals.

[0094] Operations 600 may begin at 605 by receiving a conditional handover command from a serving cell for handing over a UE to a target neighbor cell, wherein the conditional handover command includes one or more trigger conditions for performing a handover to a candidate neighbor cell.

[0095] At 610, the UE monitors one or more first signals from candidate target cells for one or more triggering conditions.

[0096] At 615, the UE performs one of stopping the timer based on performing a conditional handover to the target candidate cell or detecting that the timer has expired while monitoring one or more first signals from the candidate target cell for one or more triggering conditions. In some cases, the timer may include a T312 timer.

[0097] For example, in some cases, stopping the timer may include detecting that at least one of the one or more triggering conditions is satisfied based on the monitored one or more first signals. Thereafter, the UE may perform a conditional handover to the candidate target cell based on detecting that at least one of the one or more triggering conditions is satisfied. According to various aspects, the UE may then stop the timer based on performing the conditional handover to the candidate target cell.

[0098] According to various aspects, if the UE detects that the timer has expired while monitoring one or more first signals from the candidate target cell for one or more triggering conditions, the UE may take one or more actions. For example, in some cases, the one or more actions may include at least one of transitioning to an idle operating mode (e.g., RRC_IDLE) or initiating a connection reestablishment procedure to one or more neighboring cells (such as candidate target cells).

[0099] In some cases, operation 600 may also include detecting one or more measurement events based on monitoring of one or more measurement objects configured for the serving cell. In this case, a timer may be configured for one or more measurement events in one or more measurement objects. In addition, in this case, starting the timer may include starting the timer after detecting one or more measurement events but before detecting that one or more triggering conditions are satisfied. In addition, in some cases, operation 600 may also include sending a measurement report based on the detected one or more measurement events. In some cases, the measurement report may include parameters indicating channel / signal quality associated with the serving cell (e.g., a communication link) and one or more candidate neighboring cells.

[0100] As described above, when conditional switching to a candidate target cell is performed, the UE may stop the timer. The UE may also stop the timer in other cases. For example, in some cases, stopping the timer may also include receiving an indication of a threshold number of synchronization indications. According to various aspects, the UE may then stop the timer based on the indication of the threshold number of synchronization indications received.

[0101] In addition, in some cases, stopping the timer may also include initiating a handover procedure to switch the UE to the candidate target cell. In some cases, initiating the handover procedure is based on a handover command instructing the UE to switch to the candidate target cell. In response, the UE may stop the timer based on the initiated handover procedure.

[0102] Additionally, in some cases, stopping the timer may also include initiating a connection reestablishment procedure to reestablish the communication link. According to various aspects, in response, the UE may stop the timer based on the initiated connection reestablishment procedure.

[0103] Additionally, in some cases, stopping the timer may include determining that a second timer expires. In some cases, the second timer may include a T310 timer. According to various aspects, based on the expiration of the T310 timer, the UE may stop the T312 timer.

[0104] Furthermore, in some cases, stopping the timer may include receiving a second conditional handover command to configure one or more other candidate target cells for the UE. In response, the UE may stop the timer based on the received second conditional handover command.

[0105] Figure 7 A call flow diagram illustrating example operations for handling a situation where a conditional handover configuration is active in a UE before a RLF timer is triggered in accordance with certain aspects presented herein.

[0106] As shown, UE 702 may detect one or more measurement events at 720 and send a measurement report to a serving cell 704 (e.g., a source gNB) via a communication link between UE 702 and serving cell 704 at 722. In some cases, as discussed above, UE 702 and serving cell 704 may include UE 120 and BS 110, respectively.

[0107] According to various aspects, at 724 and 725, the serving cell may prepare a conditional handover command for handing over the UE to a candidate target cell in one or more candidate neighboring cells, such as candidate neighboring cell 706 (e.g., candidate target gNB1) or candidate neighboring cell 708 (e.g., candidate target gNB2). In some cases, the conditional handover command includes one or more trigger conditions for performing the conditional handover to the candidate target cell. Additionally, in some cases, the conditional handover command may include information for accessing the candidate target cell. Thereafter, as shown at 726, the serving cell 704 may send the conditional handover command to the UE 702. In some cases, the conditional handover command may be sent / received in an RRC reconfiguration message.

[0108] According to various aspects, after receiving the conditional handover command, the UE 702 may start the T310 timer at 728 and begin monitoring the one or more first signals from the candidate target cell for one or more triggering conditions at 730. In some cases, the UE 702 may start the T310 timer at 728 and begin monitoring the one or more first signals from the candidate target cell at 730 based on detecting that the signal quality associated with the communication link between the UE 702 and the serving cell 704 is deteriorating.

[0109] According to various aspects, during monitoring of the one or more first signals from the candidate target cell, the UE 702 may detect one or more measurement events based on monitoring of one or more measurement objects configured for the serving cell at 732. In some cases, a timer, such as a T312 timer, may be configured for one or more measurement events in the one or more measurement objects. According to various aspects, the UE 702 may then start a timer at 734 based on detecting the one or more measurement events. According to various aspects, in some cases, starting a timer may include starting a timer after detecting the one or more measurement events but before detecting that one or more triggering conditions for performing a conditional handover to the candidate target cell are satisfied.

[0110] In some cases, as shown, when another timer such as T310 is already running, UE 702 can start the timer. As described above, in response to detecting that the signal quality associated with the communication link between UE 702 and serving cell 704 is deteriorating, UE 702 may have previously started the T310 timer at 728.

[0111] According to various aspects, after detecting one or more measurement events, UE 702 may send a measurement report to serving cell 704 at 736. In some cases, based on the measurement report, serving cell 704 may cancel a conditional handover to a candidate target cell (e.g., candidate target cell 706), as shown at 738, and send a second conditional handover command with one or more other candidate target cells, as shown at 740. According to various aspects, upon receiving the second conditional handover command, UE 702 may stop the T312 timer and the T310 timer at 742.

[0112] In some cases, although Figure 7 , but UE 702 may detect that at least one of the one or more trigger conditions received in the (first) conditional handover command is satisfied based on the monitored one or more first signals from the candidate target cell. In this case, UE 702 may run / perform conditional handover to the candidate target cell based on detecting that at least one of the one or more trigger conditions is satisfied. In addition, UE 702 may stop the T312 timer based on performing the conditional handover to the candidate target cell.

[0113] In some cases, although Figure 7702 may detect that a timer (e.g., a T312 timer) has expired while monitoring one or more first signals from a candidate target cell for one or more trigger conditions. In this case, the UE 702 may take one or more actions, such as switching to an idle operation mode (e.g., RRC_IDLE) or initiating a connection reestablishment procedure to one or more neighboring cells (e.g., a candidate target cell).

[0114] According to various aspects, Figure 7 The operations shown in FIG. 1 show that the UE may have been configured with a conditional handover received via an RRC message and is monitoring one or more trigger conditions received in the conditional handover command. According to various aspects, for example, when the UE is monitoring the trigger conditions, the T312 timer may be started due to one or more measurement event triggers for a measurement object configured with T312 and configured for a normal HO report or a conditional handover cell report.

[0115] Figure 8 A communication device 800 is shown, which may include devices configured to perform operations of the techniques disclosed herein (such as Figure 4-Figure 5 800 includes various components (e.g., corresponding to means plus function components) of the communication device 800. The communication device 800 includes a processing system 802 coupled to a transceiver 808. The transceiver 808 is configured to send and receive signals, such as the various signals described herein, for the communication device 800 via an antenna 810. The processing system 802 may be configured to perform processing functions of the communication device 800, including processing signals received and / or to be transmitted by the communication device 800.

[0116] The processing system 802 includes a processor 804 coupled to a computer readable medium / memory 812 via a bus 806. In some aspects, the computer readable medium / memory 812 is configured to store instructions (e.g., computer executable code) that, when executed by the processor 804, cause the processor 804 to perform Figure 4-Figure 5 The operations shown, or other operations for performing various techniques discussed herein for handling radio link failure timers in the presence of conditional handover commands. In some aspects, the computer readable medium / memory 812 stores the operations for performing Figure 4-Figure 5For example, the computer-readable medium / memory 812 stores code 814 for communicating with a serving cell via a communication link; code 816 for monitoring at least one of one or more signals from a serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; code 818 for detecting one or more measurement events based on the monitoring, wherein a timer is configured for one or more measurement events in one or more measurement objects; code 820 for starting a timer based on detecting the one or more measurement events; code 822 for sending a measurement report based on the detected one or more measurement events; code 824 for receiving a conditional handover command for handing the UE over to a candidate target cell in one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing a conditional handover to the candidate target cell; and code 826 for stopping the timer based on the received conditional handover command.

[0117] In some aspects, processor 804 may include circuitry configured to execute code stored in computer-readable medium / memory 812, such as for executing Figure 4-Figure 5 . For example, the processor 804 includes a circuit 828 for communicating with a serving cell via a communication link; a circuit 830 for monitoring at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; a circuit 832 for detecting one or more measurement events based on the monitoring, wherein a timer is configured for one or more measurement events in one or more measurement objects; a circuit 834 for starting a timer based on detecting the one or more measurement events; a circuit 836 for sending a measurement report based on the detected one or more measurement events; a circuit 838 for receiving a conditional handover command for handing over the UE to a candidate target cell in the one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing the conditional handover to the candidate target cell; and a circuit 840 for stopping the timer based on the received conditional handover command.

[0118] Fig. 9 A communication device 900 is shown, which may include devices configured to perform operations of the techniques disclosed herein (such as Figure 6-Figure 7900 ). The communication device 900 includes a processing system 802 coupled to a transceiver 908. The transceiver 908 is configured to send and receive signals, such as the various signals described herein, for the communication device 900 via an antenna 910. The processing system 902 may be configured to perform processing functions for the communication device 900, including processing signals received and / or to be transmitted by the communication device 900.

[0119] The processing system 902 includes a processor 904 coupled to a computer readable medium / memory 912 via a bus 906. In some aspects, the computer readable medium / memory 912 is configured to store instructions (e.g., computer executable code) that, when executed by the processor 904, cause the processor 904 to perform Figure 6-Figure 7 , or other operations for performing the various techniques discussed herein for handling a radio link failure timer in the presence of a conditional handover command. In some aspects, the computer readable medium / memory 912 stores the operations for performing Figure 6-Figure 7 For example, the computer-readable medium / memory 912 stores code 914 for receiving a conditional handover command from a serving cell for handing over a UE to a target neighboring cell, wherein the conditional handover command includes one or more trigger conditions for performing a handover to a candidate target cell; code 916 for monitoring; and code 918 for performing one of stopping a timer based on performing a conditional handover to a target candidate cell or detecting that a timer has expired while monitoring one or more first signals from a candidate target cell for one or more trigger conditions.

[0120] In some aspects, processor 904 may include circuitry configured to execute code stored in computer-readable medium / memory 912, such as for executing Figure 6-Figure 7 For example, the processor 804 includes a circuit 920 for receiving a conditional handover command for handing over the UE to a target neighboring cell from a serving cell, wherein the conditional handover command includes one or more trigger conditions for performing a handover to a candidate target cell; a circuit 922 for monitoring; and a circuit 924 for performing one of stopping a timer based on performing a conditional handover to a target candidate cell or detecting that a timer has expired while monitoring one or more first signals from a candidate target cell for one or more trigger conditions.

[0121] The techniques described herein may be used for various wireless communication technologies such as NR (e.g., 5G NR), 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, and the like. 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 the Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are versions 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). NR is an emerging wireless communication technology under development.

[0122] The techniques described herein can be used for the above wireless networks and radio technologies as well as other wireless networks and radio technologies. For clarity, although terms commonly associated with 3G, 4G and / or 5G wireless technologies may be used herein to describe various aspects, various aspects of the present disclosure may be applied to other communication systems based on generations.

[0123] In 3GPP, the term "cell" can refer to the coverage area of ​​a Node B (NB) and / or a NB subsystem serving the 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 transmit receive point (TRP) can be used interchangeably. A BS can provide communication coverage for a macro cell, a pico cell, a femto cell and / or other types of cells. A macro cell can cover a relatively large geographic area (e.g., a radius of several kilometers) and can allow unrestricted access to UEs with service subscriptions. A pico cell can cover a relatively small geographic area and can allow unrestricted access to UEs with service subscriptions. A femto cell can cover a relatively small geographic area (e.g., a home) and can allow restricted access to UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in a home, etc.). A BS for a macro cell can be referred to as a macro BS. A BS for a pico cell can be referred to as a pico BS. A BS for a femto cell can be referred to as a femto BS or a home BS.

[0124] UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, customer premises equipment (CPE), cellular phone, smart phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, appliance, medical device or medical device, biosensor / device, wearable device (such as smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.)), entertainment device (e.g., music device, video device, satellite radio, etc.), vehicle component or sensor, smart meter / sensor, industrial manufacturing equipment, global positioning system device, or any other suitable device configured to communicate via 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., which can communicate with a BS, another device (e.g., a remote device), or some other entity. For example, a wireless node can provide connectivity to or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs can be considered Internet of Things (IoT) devices, which can be narrowband IoT (NB-IoT) devices.

[0125] Some 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 divide the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as frequency tones, bins, etc. Each subcarrier can be modulated with data. In general, modulation symbols are sent in the frequency domain using OFDM and in the time domain using SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, the spacing of the subcarriers can be 15 kHz, and the minimum resource allocation (called a "resource block" (RB)) can be 12 subcarriers (or 180 kHz). Therefore, for system bandwidths of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), the nominal fast Fourier transform (FFT) size can be equal to 128, 256, 512, 1024, or 2048, respectively. The system bandwidth can also be divided into subbands. For example, one subband can cover 1.08 MHz (e.g., 6 RBs), and for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, there can be 1, 2, 4, 8, or 16 subbands, respectively. In LTE, the basic transmission time interval (TTI) or packet duration is a 1 ms subframe.

[0126] NR can utilize OFDM with CP on both the uplink and downlink, and includes support for half-duplex operation using TDD. In NR, the subframe is still 1 ms, but the basic TTI is called a time slot. Depending on the subcarrier spacing, the subframe contains a variable number of time slots (e.g., 1, 2, 4, 8, 16, ... time slots). NR RB is 12 consecutive frequency subcarriers. NR can support a basic subcarrier spacing of 15 KHz, and other subcarrier spacings can be defined relative to the basic subcarrier spacing, such as 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and time slot lengths vary with the subcarrier spacing. The CP length also depends on the subcarrier spacing. Beamforming can be supported, and the beam direction can be dynamically configured. MIMO transmission with precoding can also be supported. In some examples, the MIMO configuration in the DL can support up to 8 transmit antennas, with multi-layer DL transmission of up to 8 streams and up to 2 streams per UE. In some examples, multi-layer transmission of up to 2 streams per UE can be supported. Aggregation of multiple cells up to 8 serving cells can be supported.

[0127] In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communications between some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communications, the subordinate entity utilizes the resources allocated by the scheduling entity. The base station is not the only entity that can act as a scheduling entity. In some examples, a UE may act as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs may use the resources scheduled by the UE for wireless communications. In some examples, a UE may act as a scheduling entity in a peer-to-peer (P2P) network and / or a mesh network. In the mesh network example, in addition to communicating with the scheduling entity, UEs may also communicate directly with each other.

[0128] In some examples, two or more slave entities (e.g., UEs) can communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relay, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical grids, and / or various other suitable applications. In general, a sidelink signal may refer to a signal that is transmitted from one slave entity (e.g., UE1) to another slave entity (e.g., UE2) without relaying the communication through a scheduling entity (e.g., UE or BS), even though the scheduling entity may be used for scheduling and / or control purposes. In some examples, licensed spectrum may be used to communicate sidelink signals (unlike wireless local area networks, which typically use unlicensed spectrum).

[0129] The methods disclosed herein include one or more steps or actions for implementing these methods. Without departing from the scope of the claims, the method steps and / or actions can be interchangeable with each other. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions can be modified without departing from the scope of the claims.

[0130] 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, ab, ac, bc, and abc, as well as any combination of multiples of the same element (e.g., aa, aaa, aab, aac, abb, acc,bb, bbb, bbc, cc, and ccc, or any other order of a, b, and c).

[0131] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, processing, deriving, investigating, looking up (e.g., looking up in a table, a database, or another data structure), ascertaining, etc. In addition, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. In addition, "determining" may include resolving, selecting, choosing, establishing, etc.

[0132] The preceding 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 apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown here, but to conform to the full scope consistent with the language of the claims, wherein unless otherwise stated, the reference to an element in the singular form does not mean "one and only one", but "one or more". Unless otherwise specified, the term "some" refers to one or more. All structural and functional equivalents of the elements throughout the various aspects described in the present disclosure that are known or will be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, regardless of whether such disclosure is explicitly stated in the claims, the content disclosed herein is not intended to be dedicated to the public. No claim element shall be interpreted under the provisions of Section 112 (f) of Title 35 of the United States Code unless the element is explicitly stated using the phrase "a component for..." or, in the case of a method claim, the element is stated using the phrase "a step for..."

[0133] The various operations of the above methods may be performed by any suitable component capable of performing the corresponding functions. The component may include (multiple) various hardware and / or software components and / or (multiple) modules, including but not limited to circuits, application specific integrated circuits (ASICs), or processors. Generally, where operations are shown in a figure, these operations may have corresponding parts-plus-function components with similar numbers.

[0134] The various illustrative logical blocks, modules, and circuits described in conjunction with the present disclosure may be implemented or executed 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 alternatively, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, a combination of one or more microprocessors with a DSP core, or any other such configuration.

[0135] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system may be implemented using a bus architecture. Depending on the specific application and overall design constraints of the processing system, the bus may include any number of interconnecting buses and bridges. The bus may link various circuits together, including a processor, a machine-readable medium, and a bus interface. The bus interface may be used to connect a network adapter, etc., 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 user terminal 120 (see Figure 1 ), a user interface (e.g., keyboard, 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, etc., which are well known in the art and are not described further. The processor may be implemented with one or more general and / or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits that can execute software. Those skilled in the art will recognize how to best implement the functionality of the described processing system based on the specific application and the overall design constraints imposed on the entire system.

[0136] If implemented in software, these functions can be stored or sent to a computer-readable medium as one or more instructions or codes. Software should be broadly understood as instructions, data, or any combination thereof, whether it refers to software, firmware, middleware, microcode, hardware description language, or other. Computer-readable media include computer storage media and communication media, and communication media include any media that facilitates the transfer of computer programs from one place to another. The processor can be responsible for managing the bus and general processing, including executing software modules stored on a machine-readable storage medium. The computer-readable storage medium can be coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Alternatively, the storage medium can be integrated into the processor. For example, the machine-readable medium may include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium with instructions stored thereon separated from the wireless node, all of which can be accessed by the processor through a bus interface. Alternatively or additionally, the machine-readable medium or any part thereof can be integrated into the processor, such as in the case of a cache and / or a general register file. For example, examples of machine-readable storage media may include 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 disks, or any other suitable storage media or any combination thereof. Machine-readable media may be embodied in a computer program product.

[0137] A software module may include a single instruction or multiple instructions and may be distributed across several different code segments, different programs, and multiple storage media. A computer-readable medium may include multiple software modules. A software module includes instructions that, when executed by a device such as a processor, cause a processing system to perform various functions. A software module may include a sending module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. For example, when a triggering event occurs, a software module may be loaded from a hard drive into a RAM. During the execution of a software module, a processor may load some instructions into a cache to increase access speed. Then, one or more cache lines may be loaded into a general register file for execution by a processor. When referring to the functions of the following software modules, it should be understood that such functions are implemented by a processor when executing instructions from the software module.

[0138] In addition, any connection is properly referred to as a computer-readable medium. For example, if the software is sent from a website, server or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology (such as infrared (IR), radio and microwave), the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technology (such as infrared, radio and microwave) are all included in the definition of medium. The optical disk and disk (disc) used here include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray® disc, where disks usually reproduce data magnetically, while optical discs reproduce data optically with lasers. Therefore, in some aspects, computer-readable media may include non-temporary computer-readable media (e.g., tangible media). In addition, for other aspects, computer-readable media may include temporary computer-readable media (e.g., signals). The above combination should also be included in the scope of computer-readable media.

[0139] Thus, certain aspects may include a computer program product for performing the operations presented herein. For example, such a computer program product may include 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, for performing the operations described herein and in Figure 4-Figure 7 The operations shown in the instructions.

[0140] In addition, it should be understood that the modules and / or other suitable means for performing the methods and techniques described herein can be downloaded and / or otherwise obtained by the user terminal and / or base station. For example, such a device can be coupled to a server to facilitate the transmission of components for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage device (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or a floppy disk, etc.), so that the user terminal and / or base station can obtain the various methods when the storage device is coupled or provided to the device. In addition, any other suitable technology for providing the methods and techniques described herein to the device can be utilized.

[0141] It should be understood that the claims are not limited to the precise configuration and components described 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

1. A method for wireless communication by a user equipment UE, comprising: communicating with the serving cell via a communication link; monitoring at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detecting the one or more measurement events based on the monitoring, wherein a timer is configured for the one or more measurement events in the one or more measurement objects; starting the timer based on detecting the one or more measurement events; sending a measurement report based on the detected one or more measurement events; receiving a conditional handover command for handing over the UE to a candidate target cell among the one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing the conditional handover to the candidate target cell; and The timer is stopped based on the received conditional switching command, wherein stopping the timer further comprises: receiving an indication of a threshold number of synchronization indications; and The timer is stopped based on receiving an indication of a threshold number of synchronization indications.

2. The method according to claim 1, wherein: Stopping the timer further includes: Initiating a handover process to handover the UE to the candidate target cell; and The timer is stopped based on the initiating handover procedure.

3. The method according to claim 2, wherein: Initiating the handover procedure is based on a handover command instructing the UE to handover to the candidate target cell.

4. The method according to claim 1, wherein: The timer includes a T312 timer.

5. The method according to claim 1, wherein: The one or more measurement objects are configured by the serving cell to report at least one of normal handover HO, make-before-make HO, random access channel-free RACH HO or conditional HO to the one or more candidate neighboring cells.

6. A method for wireless communication by a user equipment UE, comprising: communicating with the serving cell via a communication link; monitoring at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detecting the one or more measurement events based on the monitoring, wherein a timer is configured for the one or more measurement events in the one or more measurement objects; starting the timer based on detecting the one or more measurement events; sending a measurement report based on the detected one or more measurement events; receiving a conditional handover command for handing over the UE to a candidate target cell among the one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing the conditional handover to the candidate target cell; and The timer is stopped based on the received conditional switching command, wherein stopping the timer further comprises: Initiating a connection reestablishment procedure to reestablish the communication link; and The timer is stopped based on the initiated connection reestablishment procedure.

7. A method for wireless communication by a user equipment UE, comprising: communicating with the serving cell via a communication link; monitoring at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detecting the one or more measurement events based on the monitoring, wherein a timer is configured for the one or more measurement events in the one or more measurement objects; starting the timer based on detecting the one or more measurement events; sending a measurement report based on the detected one or more measurement events; receiving a conditional handover command for handing over the UE to a candidate target cell among the one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing the conditional handover to the candidate target cell; and The timer is stopped based on the received conditional switching command, wherein stopping the timer further comprises: determining that a second timer expires; and The timer is stopped based on expiration of the second timer.

8. The method according to claim 7, wherein: The second timer includes a T310 timer.

9. The method according to claim 7, wherein: The timer includes a T312 timer.

10. The method according to claim 7, wherein: The one or more measurement objects are configured by the serving cell to report at least one of normal handover HO, make-before-make HO, random access channel-free RACH HO or conditional HO to the one or more candidate neighboring cells.

11. A processing system for wireless communication by a user equipment UE, comprising: One or more processors, individually or collectively configured to execute instructions stored on one or more memories, and cause the UE to: communicating with the serving cell via a communication link; monitoring at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detecting the one or more measurement events based on the monitoring, wherein a timer is configured for the one or more measurement events in the one or more measurement objects; starting the timer based on detecting the one or more measurement events; sending a measurement report based on the detected one or more measurement events; receiving a conditional handover command for handing over the UE to a candidate target cell among the one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing the conditional handover to the candidate target cell; and and stopping the timer based on the received conditional switching command, wherein, to stop the timer, the one or more processors are further configured to: receiving an indication of a threshold number of synchronization indications; and The timer is stopped based on receiving an indication of a threshold number of synchronization indications.

12. The processing system according to claim 11, wherein: In order to stop the timer, the one or more processors are further configured to cause the UE to: Initiating a handover procedure to hand over the UE to the candidate target cell, wherein initiating the handover procedure is based on a handover command instructing the UE to hand over to the candidate target cell; as well as The timer is stopped based on the initiating handover procedure.

13. The processing system of claim 11, wherein: The timer includes a T312 timer.

14. The processing system of claim 11, wherein: The one or more measurement objects are configured by the serving cell to report at least one of normal handover HO, make-before-make HO, random access channel-free RACH HO or conditional HO to the one or more candidate neighboring cells.

15. A processing system for wireless communication by a user equipment UE, comprising: One or more processors, individually or collectively configured to execute instructions stored on one or more memories, and cause the UE to: communicating with the serving cell via a communication link; monitoring at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detecting the one or more measurement events based on the monitoring, wherein a timer is configured for the one or more measurement events in the one or more measurement objects; starting the timer based on detecting the one or more measurement events; sending a measurement report based on the detected one or more measurement events; receiving a conditional handover command for handing over the UE to a candidate target cell among the one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing the conditional handover to the candidate target cell; and The timer is stopped based on the received conditional switching command, wherein, in order to stop the timer, the one or more processors are further configured to: Initiating a connection reestablishment procedure to reestablish the communication link; and The timer is stopped based on the initiated connection reestablishment procedure.

16. The processing system of claim 15, wherein: The timer includes a T312 timer.

17. The processing system of claim 15, wherein: The one or more measurement objects are configured by the serving cell to report at least one of normal handover HO, make-before-make HO, random access channel-free RACH HO or conditional HO to the one or more candidate neighboring cells.

18. A processing system for wireless communication by a user equipment UE, comprising: One or more processors, individually or collectively configured to execute instructions stored on one or more memories, and cause the UE to: communicating with the serving cell via a communication link; monitoring at least one of one or more signals from the serving cell or one or more signals from one or more candidate neighboring cells based at least in part on one or more measurement events configured in one or more measurement objects; detecting the one or more measurement events based on the monitoring, wherein a timer is configured for the one or more measurement events in the one or more measurement objects; starting the timer based on detecting the one or more measurement events; sending a measurement report based on the detected one or more measurement events; receiving a conditional handover command for handing over the UE to a candidate target cell among the one or more candidate neighboring cells, wherein the conditional handover command includes one or more triggering conditions for performing the conditional handover to the candidate target cell; and The timer is stopped based on the received conditional switching command, wherein, in order to stop the timer, the one or more processors are further configured to: determining that a second timer expires; and The timer is stopped based on expiration of the second timer.

19. The processing system of claim 18, wherein: The second timer includes a T310 timer.

20. The processing system of claim 18, wherein: The timer includes a T312 timer.

21. The processing system of claim 18, wherein: The one or more measurement objects are configured by the serving cell to report at least one of normal handover HO, make-before-make HO, random access channel-free RACH HO or conditional HO to the one or more candidate neighboring cells.

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