Communications device and method

Abstract

Embodiments of this disclosure relate to communication apparatuses and methods. In one aspect, when an execution condition for a candidate cell associated with a configuration for a conditional mobility procedure is determined to be met, the terminal device skips the RA procedure during the conditional mobility procedure to the candidate cell if the condition is met. The condition includes at least one of the following: a TA measurement for the candidate cell is configured for the terminal device, a TA maintained by the terminal device for the candidate cell or a TAG associated with the candidate cell is valid, or a CG is available for the candidate cell. In this way, conditional mobility based on RACH-free operation can be performed.

Description

Technical Field

[0001] The embodiments of this disclosure generally relate to the field of telecommunications, and particularly to apparatus and methods for communications for conditional mobility. Background Technology

[0002] Conditional mobility is a mobility procedure that is triggered when the execution conditions of the candidate cells associated with the mobility procedure are met. For example, a conditional mobility procedure may include conditional Layer 1 (L1) / Layer 2 (L2) triggered mobility (LTM), conditional handover (CHO), or conditional primary / secondary cell (PSCell) change. However, the implementation of conditional mobility procedures is still incomplete and requires further development. Summary of the Invention

[0003] In general, embodiments of this disclosure provide communication methods, devices, and computer storage media for conditional mobility.

[0004] In a first aspect, a terminal device is provided. The terminal device includes a processor. The processor is configured to cause the terminal device to: determine that an execution condition for a candidate cell associated with a configuration for a conditional mobility procedure is met; and, based on the determination that the condition is met, skip a random access procedure during a conditional mobility procedure to the candidate cell, the condition including at least one of the following: a timing advance measurement for the candidate cell is configured for the terminal device, a timing advance maintained by the terminal device for the candidate cell or a timing advance group associated with the candidate cell is valid, or a configuration authorization is available for the candidate cell.

[0005] In a second aspect, a terminal device is provided. The terminal device includes a processor. The processor is configured to cause the terminal device to: determine that a process for reporting failures in a primary or secondary cell group is initiated; and to stop or suspend the evaluation of conditional cell handover in LTM.

[0006] In a third aspect, a method of communication is provided. The method includes: at a terminal device, determining that an execution condition for a candidate cell associated with a configuration for a conditional mobility procedure is met; and, based on the determination that the condition is met, skipping a random access procedure during a conditional mobility procedure to the candidate cell, the condition including at least one of the following: a timing advance measurement for the candidate cell is configured for the terminal device, a timing advance maintained by the terminal device for the candidate cell or a timing advance group associated with the candidate cell is valid, or a configuration authorization is available for the candidate cell.

[0007] In a fourth aspect, a communication method is provided. The method includes: at a terminal device, determining that a process for reporting failures in a primary or secondary cell group is initiated; and stopping or suspending the assessment of conditional cell handover in LTM.

[0008] In a fifth aspect, a computer-readable medium is provided having instructions stored thereon. When executed on at least one processor, the instructions cause the at least one processor to perform the method according to a third or fourth aspect of this disclosure.

[0009] Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0010] The above and other objects, features, and advantages of this disclosure will become more apparent from the more detailed description of some embodiments thereof in the accompanying drawings, in which:

[0011] Figure 1 The illustration shows an example communication network in which some embodiments of the present disclosure may be implemented;

[0012] Figure 2 The illustration shows a signaling diagram illustrating an example process of communication for conditional mobility according to an embodiment of the present disclosure;

[0013] Figure 3A The illustration shows an example of determining the validity of stored signal measurement values ​​according to an embodiment of the present disclosure;

[0014] Figure 3B The illustration shows an example of determining the validity of current signal measurement values ​​according to an embodiment of the present disclosure;

[0015] Figure 4 The illustration shows a signaling diagram illustrating an example process of communication for conditional LTM according to an embodiment of the present disclosure;

[0016] Figure 5 The illustration shows a flowchart of an example communication method implemented at a terminal device according to some embodiments of the present disclosure;

[0017] Figure 6 The illustration shows a flowchart of another example communication method implemented at a terminal device according to some embodiments of the present disclosure; and

[0018] Figure 7 A simplified block diagram of an apparatus suitable for implementing embodiments of the present disclosure is shown.

[0019] Throughout the accompanying drawings, the same or similar reference numerals denote the same or similar elements. Detailed Implementation

[0020] The principles of this disclosure will now be described with reference to some embodiments. It should be understood that these embodiments are described merely for illustration and to help those skilled in the art understand and implement this disclosure, and do not imply any limitation on the scope of this disclosure. The disclosure described herein can be implemented in various other ways besides those described below.

[0021] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0022] As used herein, the term "terminal device" refers to any device with wireless or wired communication capabilities. Examples of terminal devices include, but are not limited to, user equipment (UE), personal computers, desktop computers, mobile phones, cellular phones, smartphones, personal digital assistants (PDAs), laptops, tablets, wearable devices, Internet of Things (IoT) devices, ultra-reliable low-latency communication (URLLC) devices, Internet of Everything (IoE) devices, machine-type communication (MTC) devices, vehicular equipment for V2X communication (where X represents a pedestrian, vehicle, or infrastructure / network), devices for integrated access and backhaul (IAB), small data transmission (SDT), mobility, multicast and broadcast services (MBS), location services, and dynamic / flexible duplex in commercial networks. The term "terminal device" can refer to: De-capped capabilities (RedCap); spacecraft or airborne vehicles in non-terrestrial networks (NTNs) (including satellites and high-altitude platforms (HAPs)) (including unmanned aerial systems (UAS)); extended reality (XR) devices (including different types of reality such as augmented reality (AR), mixed reality (MR), and virtual reality (VR)); unmanned aerial vehicles (UAVs) commonly referred to as drones (aircraft without any human pilots); devices on high-speed trains (HSTs); or image capture devices (such as digital cameras); sensors; gaming devices; music storage and playback devices; or internet devices that enable wireless or wired internet access and browsing. "Terminal devices" can also have "multicast / broadcast" characteristics to support public safety and mission-critical applications, V2X applications, transparent IPv4 / IPv6 multicast delivery, IPTV, smart TV, radio services, wireless software delivery, group communications, and IoT applications. It can also include one or more subscriber identification modules (SIMs) (referred to as multi-SIMs). The term "terminal device" is used interchangeably with UE, mobile station, subscriber station, mobile terminal, user terminal, or wireless device.

[0023] The term "network device" refers to a device that provides or hosts a cell or coverage area in which terminal devices can communicate. Examples of network devices include, but are not limited to, NodeB (or NB), evolved NodeB (eNodeB or eNB), next-generation NodeB (gNB), Transmitter Receiver Point (TRP), Remote Radio Unit (RRU), Radio Head (RH), Remote Radio Head (RRH), IAB node, low-power node (such as femtonode, piconode), reconfigurable smart surface (RIS), network control repeater, etc.

[0024] Terminal devices or network devices can have artificial intelligence (AI) or machine learning capabilities. This typically includes a model that is trained from a large amount of collected data according to a specific function and can be used to predict some kind of information.

[0025] Terminal or network devices can operate within several frequency ranges, such as FR1 (410 MHz to 7125 MHz), FR2 (24.25 GHz to 71 GHz), bands above 100 GHz, and terahertz (THz). They can also operate on licensed / unlicensed / shared spectrum. In MR-DC applications, terminal devices can have more than one connection to network devices. Terminal or network devices can operate in full-duplex, flexible-duplex, and cross-duplex modes.

[0026] Network devices can feature network energy saving and self-organizing network (SON) / minimal vehicle testing (MDT) capabilities. Terminals can have power-saving functions.

[0027] The embodiments of this disclosure can be executed in test equipment, such as signal generators, signal analyzers, spectrum analyzers, network analyzers, test terminal equipment, test network equipment, and channel simulators.

[0028] In one embodiment, the terminal device may be connected to a first network device and a second network device. One of the first and second network devices may be a master node, and the other a slave node. The first and second network devices may use different Radio Access Technologies (RATs). In one embodiment, the first network device may be a first RAT device, and the second network device may be a second RAT device. In one embodiment, the first RAT device is an eNB, and the second RAT device is a gNB. Information related to different RATs may be sent to the terminal device from at least one of the first or second network devices. In one embodiment, first information may be sent from the first network device to the terminal device, and second information may be sent directly or via the first network device from the second network device to the terminal device. In one embodiment, information related to the configuration of the terminal device configured by the second network device may be sent via the first network device from the second network device. Information related to the reconfiguration of the terminal device configured by the second network device may be sent directly or via the first network device from the second network device to the terminal device.

[0029] As used herein, unless the context explicitly indicates otherwise, the singular forms “a,” “an,” and “the” should also include the plural forms. The term “comprising” and its variations should be understood as open terms meaning “including, but not limited to.” The term “based on” should be understood as “at least partially based on.” The terms “one embodiment” and “embodiment” should be understood as “at least one embodiment.” The term “another embodiment” should be understood as “at least one other embodiment.” The terms “first,” “second,” etc., may refer to different or the same objects. Further explicit and implicit definitions may be included below.

[0030] In some examples, values, processes, or devices are referred to as “best,” “lowest,” “highest,” “smallest,” “maximum,” etc. It should be understood that such descriptions are intended to indicate that a selection can be made from a number of functional alternatives used, and that such a selection is not necessarily better, smaller, higher, or otherwise preferred than other options.

[0031] In the context of this disclosure, the terms "connected state" and "RRC_CONNECTED state" are used interchangeably, the terms "idle state" and "RRC_IDLE state" are used interchangeably, and the terms "inactive state" and "RRC_INACTIVE state" are used interchangeably. In the context of this disclosure, the term "above" is used interchangeably with "higher than or equal to" or "greater than or equal to". The term "below" is used interchangeably with "lower than or equal to" or "less than or equal to".

[0032] In the context of this disclosure, the term "cell handover" may be used interchangeably with "synchronization reconfiguration for a secondary cell group (SCG) or primary cell group (MCG)" or "cell change". The term "PSCell" refers to the SpCell of an SCG, the term "PCell" refers to the SpCell of an MCG, and the term "SpCell" refers to the primary cell of an SCG or MCG. The term "SCell" refers to a secondary cell. The term "Radio Resource Control (RRC) reconfiguration" may be used interchangeably with "RRC reconfiguration message". The term "Initial Uplink (UL) transmission" may be used interchangeably with "First Physical Uplink Shared Channel (PUSCH) transmission". The term "candidate cell" may be used interchangeably with "target candidate cell", "target cell", or "candidate target cell".

[0033] Currently, conditional mobility procedures, such as conditional LTM, CHO, or conditional PSCell changes, can be supported. To further reduce the latency of conditional mobility procedures, RACH-free operation (i.e., skipping the RA procedure) can be supported. Skipping the RA procedure can bring benefits such as reduced mobility failures, reduced downtime, and reduced signaling overhead. However, the implementation of RACH-free conditional mobility is unclear, and the implementation of conditional LTM cell handover procedures is still incomplete.

[0034] Embodiments of this disclosure provide a communication solution for conditional mobility. In one aspect, when an execution condition for a candidate cell associated with the configuration for a conditional mobility procedure is met, the terminal device skips the RA procedure during the conditional mobility procedure to the candidate cell if the condition is met. The condition includes at least one of the following: a timing advance (TA) measurement for the candidate cell, a TA maintained by the terminal device for the candidate cell or a timing advance group (TAG) associated with the candidate cell being valid, or a configuration authorization (CG) being available for the candidate cell. In this way, conditional mobility based on RACH-free operation can be performed.

[0035] On the other hand, after the process for reporting failures in the MCG or SCG is initiated, the terminal device stops or suspends the evaluation of conditional cell handover in LTM. In this way, when an MCG or SCG link fails, the terminal device can stop the evaluation of conditional LTM cell handover and continue the evaluation after the failure is recovered.

[0036] The principles and implementation of this disclosure will now be described in detail with reference to the accompanying drawings. Examples of communication networks

[0037] Figure 1The illustration shows a schematic diagram of an example communication network 100 in which some embodiments of the present disclosure may be implemented. For example... Figure 1 As shown, the communication network 100 may include terminal device 110 and network devices 120 and 130. Network device 120 provides cells 121 and 122 to serve one or more terminal devices. Network device 130 provides cells 131 and 132 to serve one or more terminal devices.

[0038] In some embodiments, network device 120 and network device 130 may be the same network device. In some embodiments, network device 120 and network device 130 may be different network devices.

[0039] It should be understood that Figure 1 The number of devices or cells given is for illustrative purposes and does not impose any limitation on the content of this disclosure. The communication network 100 may include any suitable number of network devices and / or terminal devices and / or cells suitable for implementing the present disclosure.

[0040] like Figure 1 As shown, terminal device 110 can communicate with either network device 120 or 130, for example, via a Uu interface. Network devices 120 and 130 can communicate with each other, for example, via an Xn interface. Communication in communication network 100 can conform to any suitable standard, including but not limited to Global System for Mobile Communications (GSM), Long Term Evolution (LTE), LTE Evolution, LTE-A Advanced, New Radio (NR), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), GSM EDGE Radio Access Network (GERAN), Machine Type Communication (MTC), etc. Embodiments of this disclosure can be implemented according to any generation of communication protocols currently known or to be developed in the future. Examples of communication protocols include, but are not limited to, first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G) communication protocols, 5.5G, 5G Advanced Network, or sixth-generation (6G) Network.

[0041] Communication from terminal device 110 to either network device 120 or 130 is called uplink (UL) communication, while communication from either network device 120 or 130 to terminal device 110 in the opposite direction is called downlink (DL) communication. Terminal device 110 can move between the cells of network devices 120 and 130, and possibly other network devices. In UL communication, terminal device 110 can send UL data and control information to network device 120 or 130 via the UL channel. In DL communication, network device 120 or 130 can send DL data and control information to terminal device 110 via the DL channel.

[0042] In some embodiments, terminal device 110 may be located within the coverage area of ​​cell 121 of network device 120, and terminal device 110 may communicate with network device 120 based on network configuration. In this case, cell 121 may be referred to as the serving cell of terminal device 110. Any one of cells 122, 131, and 132 may be referred to as a candidate cell of terminal device 110.

[0043] In some embodiments, terminal device 110 can establish dual connections (i.e., simultaneous connections) with network device 120 and another network device (e.g., network device 130). In some embodiments, network device 120 can act as a master node (MN). In these embodiments, terminal device 110 can communicate with network device 120 via a set of serving cells. This set of serving cells forms an MCG, and a master cell in the MCG is referred to as PCell. In some scenarios, when the execution conditions for changing the candidate cell of PCell are met, terminal device 110 can change PCell from cell 121 to a candidate cell (also called a target cell, such as cell 122). This process is referred to herein as the CHO process.

[0044] In some embodiments, network device 120 may be used as a secondary node (SN). In these embodiments, the serving cell set provided by network device 120 forms an SCG, and the primary cell in the SCG is called a PSCell. In some scenarios, when the execution conditions for candidate cells for PSCell change are met, terminal device 110 may change the PSCell from cell 121 to a candidate cell (e.g., cell 122). This process is referred to herein as the conditional PSCell change process.

[0045] In some embodiments, terminal device 110 may perform an evaluation on a set of candidate cells to allow LTM (L1 Measurement) for the set of candidate cells. If the conditions for handover to a candidate cell are met, terminal device 110 may change its serving cell (e.g., PCell or PSCell) to a candidate cell (e.g., cell 122). This process is referred to herein as a conditional LTM cell handover process.

[0046] In the context of this disclosure, the term "conditional mobility procedure" can refer to a CHO procedure, a conditional PSCell change procedure, a conditional LTM cell handover procedure, or any other existing or soon-to-be-developed conditional cell change or handover procedure.

[0047] Embodiments of this disclosure provide communication solutions for enhancing conditional mobility processes. Reference will be made below. Figures 2 to 4 Describe these solutions. Example implementation of mobility without RACH conditions

[0048] For conventional or unconditional mobility procedures, if the RA procedure is skipped, TA information is provided to the terminal device, such as in mobility commands like LTM cell handover commands, HO commands, or RRCReconfiguration with reconfigurationWithSync. However, for conditional mobility procedures, TA information may not be available from the mobility commands. Therefore, it is unclear how to determine whether to skip the RA procedure used for conditional mobility procedures.

[0049] In view of this, embodiments of the present disclosure provide a communication solution for RACH-free mobility. The following will combine... Figure 2 Describe the solution.

[0050] Figure 2 The illustration shows a signaling diagram illustrating an example process 200 for communication for conditional mobility according to an embodiment of the present disclosure. For purposes of discussion, reference will be made to... Figure 1 Describe process 200. Process 200 may involve, for example, Figure 1 The terminal device 110 and network device 120 are shown. In this example, network device 120 provides a serving cell for terminal device 110. The serving cell can be the SpCell, PCCell, or PSCell of terminal device 110. It is assumed that network device 130 provides a target candidate cell for terminal device 110.

[0051] like Figure 2 As shown, network device 120 can send 210 a configuration for a conditional mobility procedure to terminal device 110, which includes execution conditions for cell change or handover to a candidate cell. In some embodiments, the conditional mobility procedure may be a conditional LTM cell handover procedure. In some embodiments, the conditional mobility procedure may be a CHO procedure. In some embodiments, the conditional mobility procedure may be a conditional PSCell change procedure. In some embodiments, network device 120 may send the configuration via an RRC reconfiguration message. It should be understood that any other suitable message is also possible.

[0052] In some embodiments, network device 120 may send a configuration list of one or more candidate cells that allow conditional mobility procedures. Each configuration in the configuration list is associated with a candidate cell and includes the execution conditions for cell change or handover to that candidate cell.

[0053] Continue to refer to Figure 2Terminal device 110 can evaluate whether the execution conditions of 220 candidate cells are met. In some embodiments, terminal device 110 can perform L1 measurements to evaluate LTM candidate cells. In some embodiments, terminal device 110 can perform L3 measurements to evaluate CHO candidate cells. In some embodiments, terminal device 110 can perform L3 measurements to evaluate candidate cells associated with changes in conditional PSCell. It should be understood that the evaluation can be performed in any suitable manner, and this disclosure is not limiting in this respect.

[0054] Continue to refer to Figure 2 When the execution conditions for a candidate cell (e.g., cell 131) are met, terminal device 110 can determine whether the RA process 230 is skipped during the conditional mobility process to the candidate cell. In other words, terminal device 110 can determine whether the conditions for skipping the RA process are met.

[0055] refer to Figure 2 In some embodiments, the condition may include a TA measurement for candidate cells configured for use by terminal device 110. That is, if terminal device 110 is configured to perform a TA measurement on a candidate cell, terminal device 110 may skip the 231 RA process during the execution of the conditional mobility procedure to the candidate cell.

[0056] refer to Figure 2 In some embodiments, the condition may include a valid TA maintained by the terminal device 110 for the candidate cell or a TAG associated with the candidate cell. That is, if a valid TA is maintained for the candidate cell or a TAG associated with the candidate cell, the terminal device 110 may skip the 232 RA process during the execution of the conditional mobility process to the candidate cell.

[0057] In some embodiments, terminal device 110 may receive a TA command from network device 120 providing a serving cell, the TA command indicating a TA maintained for a candidate cell or a TAG associated with a candidate cell. Alternatively, terminal device 110 may receive a TA command from network device 130 providing a candidate cell (e.g., cell 131).

[0058] In some embodiments, terminal device 110 may receive TA commands from network device 120 or 130 via MAC CE. In some embodiments, MAC CE may include an identifier (ID) for the configuration used in the conditional mobility procedure (i.e., the configuration associated with a candidate cell), such as LTM-CandidateId or CondReconfigId-r16. In some embodiments, MAC CE may include the ID of a TAG associated with a candidate cell. In some embodiments, MAC CE may include a first TA command for controlling the timing adjustment amount to be applied, and the first TA command may have a first bit length. For example, the first bit length may be 6 bits. In some embodiments, MAC CE may include a second TA command for controlling the timing adjustment amount to be applied, and the first TA command may have a second bit length greater than the first bit length. For example, the second bit length may be 12 bits. The second TA command may also be referred to as an absolute timing advance command. It should be understood that MAC CE may include any combination of the above information.

[0059] In some embodiments, terminal device 110 may receive a TA command from network device 120 or 130 in a Random Access Response (RAR). The RAR may be a response to the RA of a candidate cell. In some embodiments, terminal device 110 may receive DL information (e.g., Physical Downlink Control Channel (PDCCH)) from network device 120, which includes the candidate cell ID and Contention-Free Random Access (CFRA) information. In some embodiments, the CFRA information may indicate at least one of the following: an index of a random access preamble, a synchronization signal block (SSB), a physical random access channel (PRACH) mask index defining the PRACH timing associated with the SSB(s) in which a MAC entity may transmit the random access preamble, carrier information, etc. In some embodiments, terminal device 110 may send a random access preamble to network device 130. In some embodiments, terminal device 110 may receive a RAR including a TA command from network device 120 or 130.

[0060] In some embodiments, upon receiving a TA command, terminal device 110 may apply the TA command to a candidate cell or a TAG associated with the candidate cell. In some embodiments, upon receiving a TA command, terminal device 110 may start or restart a time alignment timer for the candidate cell or a TAG associated with the candidate cell. In some embodiments, terminal device 110 may store signal measurement values ​​of the candidate cell (also referred to herein as first signal measurement values ​​for convenience) upon receiving a TA command. It should be understood that the signal measurement values ​​may be Reference Received Power (RSRP), Reference Received Quality (RSRQ), or any other suitable metric.

[0061] In some embodiments, terminal device 110 may determine that TA is valid if a first signal measurement value of the candidate cell is valid when the TA command is received, and a signal measurement value of the candidate cell (also referred to herein as a second signal measurement value for convenience) is valid when the validity of TA is determined. For example, terminal device 110 may determine that TA is valid if the stored RSRP value of the candidate cell (e.g., a DL path loss reference for the candidate cell or a stored RSRP value of at least one SSB) and the current RSRP value of the candidate cell (e.g., a DL path loss reference for the candidate cell or a current RSRP value of at least one SSB) are valid.

[0062] In some embodiments, if the timing at which the terminal device 110 completes the measurement of the first signal measurement value (also referred to herein as the first timing) falls within a time range (also referred to herein as the first time range) before or after the timing at which the TA command is received (also referred to herein as the second timing) the terminal device 110 determines that the first signal measurement value is valid. For example, the second timing could be the terminal device 110 obtaining the latest TA between the DL and UL for the candidate cell via the TA command in MAC CE or RAR. N TA The time frame will be discussed below. Figure 3A Describe an example.

[0063] Figure 3A Figure 300A illustrates an example determination of the validity of stored signal measurement values ​​according to an embodiment of the present disclosure. Figure 3A As shown, RSRP1 represents the first signal measurement value, T1' represents the first timing when the terminal device 110 completes the first signal measurement value, T1 represents the second timing when the TA command is received, and T represents the first time range. If the following equation (1) is true, the terminal device 110 can determine that RSRP1 is valid. (T1-T)≤T1'≤(T1+T) (1)

[0064] In some embodiments, if the timing at which the terminal device 110 completes the measurement of the second signal measurement value (also referred to herein as the third timing, for convenience) falls within a time range (also referred to herein as the second time range, for convenience) preceding the timing at which the validity of the TA is determined (also referred to herein as the fourth timing, for convenience)... then the terminal device 110 can determine that the second signal measurement value is valid. For example, the fourth timing could be the time when the terminal device 110 performs TA verification to determine whether to skip the RA process of the conditional mobility procedure. The following will combine... Figure 3B Describe an example.

[0065] Figure 3B Figure 300B illustrates an example determination of the validity of current signal measurement values ​​according to an embodiment of the present disclosure. Figure 3B As shown, RSRP2 represents the second signal measurement value, T2' represents the third timing when the terminal device 110 completes the measurement of the second signal measurement value, T2 represents the fourth timing when the validity of TA is determined, and T' represents the second time range. If the following equation (2) is true, then the terminal device 110 can determine that RSRP2 is valid. (T2-T')≤T2'≤T2 (2)

[0066] In some embodiments, if at least one of RSRP1 or RSRP2 is deemed invalid, the terminal device 110 may not skip the RA process of the conditional mobility procedure. In some embodiments, the first time range (T) and the second time range (T') may be the same. In some embodiments, the first time range (T) and the second time range (T') may be different.

[0067] In some embodiments, terminal device 110 may determine that TA is valid if the difference between the first signal measurement and the second signal measurement is less than a threshold difference. That is, the second signal measurement has not been increased or decreased by more than the threshold difference compared to the first signal measurement. In some embodiments, the threshold difference may be configured in the configuration used for the conditional mobility procedure (i.e., the configuration associated with candidate cells). In some embodiments, the threshold difference may be predefined.

[0068] In some embodiments, if a time alignment timer for a candidate cell or a TAG associated with a candidate cell is running, the terminal device 110 may determine that the TA is valid.

[0069] It should be understood that any combination of conditions used for TA verification may also be feasible. In some embodiments, terminal device 110 may determine that TA is valid if at least one of the following is satisfied: a first signal measurement of the candidate cell is valid when the TA command is received; a second signal measurement of the candidate cell is valid when the validity of the TA is determined; the difference between the first signal measurement and the second signal measurement is less than a threshold difference; or a time alignment timer for the candidate cell or the TAG associated with the candidate cell is running.

[0070] Continue to refer to Figure 2 In some embodiments, the conditions for skipping the RA process may include the availability of a CG for a candidate cell. That is, if a CG exists that will be used for a candidate cell, the terminal device 110 may skip the RA process 233 during the execution of the conditional mobility process to the candidate cell.

[0071] In some embodiments, if the time interval between the timing at which the validity of the TA is determined (i.e., T2) and the timing of the CG is greater than a time range after the timing (i.e., T2) (also referred to herein as the third time range for convenience), then the terminal device 110 may determine that the CG is not available for the candidate cell. In some embodiments, if the time interval is less than the third time range after the timing (i.e., T2), then the terminal device 110 may determine that the CG is available for the candidate cell. In other words, if the time interval between the initiation of TA verification and the timing of the first available / valid CG for initial UL / PUSCH transmission is greater than the third time range after T2, then the terminal device 110 may consider that there is no CG to be used in the conditional mobility procedure. Otherwise, the terminal device 110 may consider that there is a CG to be used in the conditional mobility procedure. In some embodiments, the third time range is the same as the first time range (T) or the second time range (T'). In some embodiments, the third time range is different from the first time range (T) or the second time range (T').

[0072] In some embodiments, if the time alignment timer for a candidate cell or a TAG associated with a candidate cell is not running at the time of the CG, the terminal device 110 may determine that the CG is not available for the candidate cell. In some embodiments, if the time alignment timer is running at the time of the CG, the terminal device 110 may determine that the CG is available for the candidate cell.

[0073] It should be understood that any combination of conditions for skipping the RA process is also feasible. In some embodiments, terminal device 110 may skip the RA process during the execution of the conditional mobility process to the candidate cell if at least one of the following is satisfied: terminal device 110 is configured to perform TA measurement for the candidate cell; there is a valid TA maintained for the candidate cell or a TAG associated with the candidate cell; or there is a CG to be used for the candidate cell.

[0074] Continue to refer to Figure 2 When the conditions for skipping the RA process are met, the terminal device 110 may skip the 240 RA process during the conditional mobility process to the candidate cell.

[0075] So far, the operations for determining whether to skip the RA process have been described. In some embodiments, the operation of applying the TA can be performed after the operation of determining whether to skip the RA process has been performed. In some embodiments, if the RA process is determined to be skipped, the terminal device 110 can apply the measured TA to the primary TAG and start or restart the time alignment timer for the primary TAG. The primary TAG may refer to the TAG of the SpCell containing the MAC entity. In some embodiments, if the RA process is determined to be skipped, the terminal device 110 can apply the maintained TA of the candidate cell or the TAG associated with the candidate cell to the primary TAG and set the time alignment timer for the primary TAG to be the same as the time alignment timer for the candidate cell or the TAG associated with the candidate cell. In some embodiments, if the RA process is determined to be skipped, the terminal device 110 can apply the maintained TA of the candidate cell or the TAG associated with the candidate cell to the primary TAG and start or restart the time alignment timer for the primary TAG.

[0076] In some embodiments, the operation of applying the TA can be performed before the operation of determining whether to skip the RA process. In some embodiments, the terminal device 110 may first apply the measured TA to the primary TAG or candidate cell or a TAG associated with the candidate cell, and start and restart the time alignment timer for the primary TAG or candidate cell or a TAG associated with the candidate cell, and then the terminal device 110 may determine whether to skip the RA process. In some embodiments, the terminal device 110 may first apply the maintained TA of the candidate cell or a TAG associated with the candidate cell to the primary TAG, and set the time alignment timer for the primary TAG to be the same as the time alignment timer for the candidate cell or a TAG associated with the candidate cell, and then the terminal device 110 may determine whether to skip the RA process. In some embodiments, the terminal device 110 may first apply the maintained TA to the primary TAG, and start or restart the time alignment timer for the primary TAG, and then the terminal device 110 may determine whether to skip the RA process.

[0077] To date, a solution for RACH-free conditional mobility has been described. This solution enables end devices to perform RACH-free conditional mobility. Example implementation of conditional LTM

[0078] Traditionally, if an MCG or SCG failure occurs, the terminal device can send a message to the network device to report the MCG or SCG failure information. However, it is unclear whether the terminal device continues to evaluate the conditional LTM while the MCG or SCG failure information is being transmitted.

[0079] In view of this, embodiments of this disclosure provide a communication solution for conditional LTM. The following will combine... Figure 4 Describe the solution.

[0080] Figure 4 The illustration shows a signaling diagram illustrating an example process 400 for communication for conditional LTM according to an embodiment of the present disclosure. For discussion purposes, reference will be made to... Figure 1 Describe process 400. Process 400 may involve, for example, Figure 1 The terminal device 110 and network device 120 are shown. In this example, network device 120 provides a serving cell for terminal device 110. The serving cell can be SpCell, PCCell, or PSCell of terminal device 110.

[0081] like Figure 4 As shown, network device 120 can send a configuration 410 for conditional LTM to terminal device 110, which includes execution conditions for LTM cell handover to a candidate cell. In some embodiments, network device 120 can send this configuration via an RRC reconfiguration message. It should be understood that any other suitable message is also possible.

[0082] In some embodiments, network device 120 may send a configuration list of one or more candidate cells that allow LTM. Each configuration in the configuration list is associated with a candidate cell and includes the execution conditions for LTM cell handover to that candidate cell.

[0083] Continue to refer to Figure 4 Terminal device 110 can evaluate whether the execution conditions for LTM cell handover from 420 to LTM candidate cell are met. In some embodiments, terminal device 110 can perform L1 measurements to evaluate LTM candidate cells.

[0084] Continue to refer to Figure 4 Terminal device 110 can determine that the process 430 used to report failures in the MCG or SCG has been initiated. That is, when an MCG or SCG failure occurs, terminal device 110 can initiate a report of the MCG or SCG failure. When an MCG failure report is initiated, terminal device 110 can start timer T316.

[0085] Continue to refer to Figure 4After determining that a process for reporting MCG or SCG failure has been initiated, terminal device 110 may stop or pause the conditional LTM evaluation. In some embodiments, the RRC layer of terminal device 110 may instruct lower layers of terminal device 110 (e.g., MAC layer or PHY layer) to stop or pause the evaluation of LTM PCell handover and LTM PSCell handover. In some embodiments, after determining that a process for reporting MCG or SCG failure has been initiated, terminal device 110 may continue the conditional LTM evaluation.

[0086] Continue to refer to Figure 4 Once the conditions are met, the terminal device 110 can initiate, resume, or continue the evaluation of the 450 condition LTM.

[0087] In some embodiments where an MCG failure report is initiated, if a HO command for PCell change is received, terminal device 110 can initiate, resume, or continue the evaluation of conditional LTM. For example, if the MCG's spCellConfig includes an RRCReconfiguration with reconfigurationWithSync, and the T316 timer is running, terminal device 110 can initiate, resume, or continue the evaluation of conditional LTM.

[0088] In some embodiments where an MCG failure report is initiated, if the PCell change in the HO command completes successfully, the terminal device 110 can initiate, resume, or continue the evaluation of the conditional LTM. For example, if the RA procedure triggered by RRCReconfiguration with reconfigurationWithSync in spCellConfig for the MCG completes successfully, the terminal device 110 can initiate, resume, or continue the evaluation of the conditional LTM.

[0089] In some embodiments where an MCG failure report is initiated, if an LTM cell handover command for PCell handover is received, terminal device 110 can initiate, resume, or continue the evaluation of conditional LTM. For example, if an LTM cell handover command for an LTM candidate cell configuration associated with the MCG is received, terminal device 110 can initiate, resume, or continue the evaluation of conditional LTM. For example, if MN (e.g., network device 120) sends information about an LTM cell handover command to SN (e.g., network device 130), SN can generate an LTM cell handover command based on the received information and send the LTM cell handover command to terminal device 110.

[0090] In some embodiments where an MCG failure report is initiated, if the PCell handover in the LTM cell handover command is successfully completed, the terminal device 110 can initiate, resume, or continue the evaluation of conditional LTM. For example, if the LTM cell handover for the LTM candidate cell configuration associated with the MCG is successfully completed, the terminal device 110 can initiate, resume, or continue the evaluation of conditional LTM.

[0091] In some embodiments where an SCG failure report is initiated, if an RRC reconfiguration message with synchronized reconfiguration indicating a change to the PSCell is received, the terminal device 110 can initiate, resume, or continue the evaluation of the conditional LTM. For example, if the spCellConfig of the SCG includes an RRCReconfiguration with reconfigurationWithSync, the terminal device 110 can initiate, resume, or continue the evaluation of the conditional LTM.

[0092] In some embodiments where an SCG failure report is initiated, if the PSCell change in the RRC reconfiguration message completes successfully, the terminal device 110 can initiate, resume, or continue the evaluation of the conditional LTM. For example, if the RA procedure triggered by reconfigurationWithSync with RRCReconfiguration in spCellConfig for the SCG completes successfully, the terminal device 110 can initiate, resume, or continue the evaluation of the conditional LTM.

[0093] In some embodiments where an SCG failure report is initiated, if an LTM cell handover command for PSCell handover is received, terminal device 110 can initiate, resume, or continue the evaluation of conditional LTM. For example, if an LTM cell handover command for configuring an LTM candidate cell associated with the SCG is received, terminal device 110 can initiate, resume, or continue the evaluation of conditional LTM. For example, if the SN (e.g., network device 130) sends information about an LTM cell handover command to the MN (e.g., network device 120), the MN can generate an LTM cell handover command based on the received information and send the LTM cell handover command to terminal device 110.

[0094] In some embodiments where an SCG failure report is initiated, if the PSCell handover in the LTM cell handover command is successfully completed, the terminal device 110 can initiate, resume, or continue the evaluation of conditional LTM. For example, if the LTM cell handover for the LTM candidate cell configuration associated with the SCG is successfully completed, the terminal device 110 can initiate, resume, or continue the evaluation of conditional LTM.

[0095] To date, a solution for conditional LTM has been described. This solution allows the terminal device to halt the evaluation of conditional LTM cell handover when an MCG or SCG link fails, and to resume the evaluation after recovery.

[0096] It should be understood that the operations described in procedures 200 and 400 can be performed individually or in any suitable combination. Example implementation of the method

[0097] Therefore, embodiments of this disclosure provide a communication method implemented at a terminal device. Reference will be made below. Figure 5 and Figure 6 Describe these methods.

[0098] Figure 5 The illustration shows a flowchart of an example communication method 500 implemented at a terminal device according to some embodiments of the present disclosure. For example, method 500 can be implemented in, for example... Figure 1 The terminal device 110 shown is executed. For discussion purposes, reference will be made below. Figure 1 Method 500 is described. It should be understood that method 500 may include additional boxes not shown and / or some boxes shown may be omitted, and the scope of this disclosure is not limited in this respect.

[0099] At block 510, terminal device 110 determines that the execution conditions of the candidate cells associated with the configuration for the conditional mobility procedure are met. In some embodiments, the conditional mobility procedure may include at least one of the following: a CHO procedure; a conditional LTM cell handover procedure; or a conditional PSCell change procedure.

[0100] At box 520, terminal device 110 determines that the conditions for skipping the RA procedure are met. These conditions include at least one of the following: TA measurements for the candidate cell are configured for the terminal device; TA maintained by terminal device 110 for the candidate cell or a TAG associated with the candidate cell is valid; or CG is available for the candidate cell.

[0101] In some embodiments, terminal device 110 may determine that TA is valid based on at least one of the following: a first signal measurement value of the candidate cell is valid when a TA command instructing TA is received; a second signal measurement value of the candidate cell is valid when the validity of TA is determined; the difference between the first signal measurement value and the second signal measurement value is less than a threshold difference; or a time alignment timer for the candidate cell or the TAG associated with the candidate cell is running.

[0102] In some embodiments, if a TA command is received, the terminal device 110 may perform at least one of the following operations: apply the TA command to a candidate cell or a TAG associated with the candidate cell; start or restart a time alignment timer; or store a first signal measurement value.

[0103] In some embodiments, terminal device 110 may receive a TA command via a MAC CE from a first network device providing a serving cell (e.g., network device 120) or a second network device providing a candidate cell (e.g., network device 130). The MAC CE may include at least one of the following: an ID for configuration of a conditional mobility procedure; an ID of a TAG associated with a candidate cell; a first TA command for controlling a timing adjustment amount to be applied, the first TA command having a first bit length; or a second TA command for controlling a timing adjustment amount to be applied, the second TA command having a second bit length greater than the first bit length.

[0104] In some embodiments, terminal device 110 may receive DL information from a first network device (e.g., network device 120) providing the candidate cell. The DL information includes the candidate cell ID and CFRA information. Terminal device 110 may send a random access preamble to a second network device (e.g., network device 130) providing the candidate cell, and receive a RAR including a TA command from either the first or second network device.

[0105] In some embodiments, if the first timing at which the terminal device 110 completes the measurement of the first signal measurement value falls within a first time range before or after a second timing at which the TA command is received, the terminal device 110 may determine that the first signal measurement value is valid. In some embodiments, if the third timing at which the terminal device 110 completes the measurement of the second signal measurement value falls within a second time range before a fourth timing at which the validity of the TA is determined, the terminal device 110 may determine that the second signal measurement value is valid.

[0106] In some embodiments, if the time interval between the timing at which the validity of the TA is determined and the timing of the CG is greater than a third time range after the timing, the terminal device 110 may determine that the CG is not available for the candidate cell. In some embodiments, if the time interval is less than a third time range after the timing, the terminal device 110 may determine that the CG is available for the candidate cell. In some embodiments, if the time alignment timer of the candidate cell or the TAG associated with the candidate cell is not running at the timing of the CG, the terminal device 110 may determine that the CG is not available for the candidate cell. In some embodiments, if the time alignment timer is running at the timing of the CG, the terminal device 110 may determine that the CG is available for the candidate cell.

[0107] At box 530, terminal device 110 skips the RA process during the conditional mobility process to the candidate cell.

[0108] In some embodiments, if the RA process is skipped, the terminal device 110 may perform an operation including at least one of the following: applying the measured TA to the main TAG and starting or restarting the time alignment timer for the main TAG; applying the maintained TA to the main TAG and setting the time alignment timer for the main TAG to be the same as the time alignment timer for the candidate cell or the TAG associated with the candidate cell; or applying the maintained TA to the main TAG and starting or restarting the time alignment timer for the main TAG.

[0109] In some embodiments, if the operation is performed, the terminal device 110 may determine whether the conditions for skipping the RA process are met. The operation includes at least one of the following: applying the measured TA to the primary TAG or candidate cell or a TAG associated with the candidate cell, and starting or restarting the time alignment timer for the primary TAG or candidate cell or a TAG associated with the candidate cell; applying the maintained TA to the primary TAG, and setting the time alignment timer for the primary TAG to be the same as the time alignment timer for the candidate cell or a TAG associated with the candidate cell; or applying the maintained TA to the primary TAG, and starting or restarting the time alignment timer for the primary TAG.

[0110] Method 500 allows for the execution of conditional mobility based on RACH-free conditions.

[0111] Figure 6 The illustration shows a flowchart of another example communication method 600 implemented at a terminal device according to some embodiments of the present disclosure. For example, method 600 can be implemented as follows: Figure 1 The terminal device 110 shown is executed. For discussion purposes, reference will be made below. Figure 1Method 600 is described. It should be understood that method 600 may include additional boxes not shown and / or some boxes shown may be omitted, and the scope of this disclosure is not limited in this respect.

[0112] At box 610, terminal device 110 determines that a process for reporting failures in MCG or SCG has been initiated.

[0113] At box 620, terminal device 110 stops or pauses the evaluation of conditional cell handover in LTM. In some embodiments, terminal device 110 may instruct lower layers of terminal device 110 to stop or pause the evaluation of PCell handover and PSCell handover via the RRC layer.

[0114] In some embodiments where the process for reporting failures in the MCG is initiated, terminal device 110 may initiate, resume, or continue the evaluation for conditional cell handover if a condition is met. This condition may include at least one of the following: an HO command for PCell change is received; an LTM cell handover command for PCell handover is received; the PCell change is successfully completed; or the PCell handover is successfully completed.

[0115] In some embodiments where the process for reporting failures in the SCG is initiated, terminal device 110 may initiate, resume, or continue the evaluation for conditional cell handover if a condition is met. This condition may include at least one of the following: an RRC reconfiguration message with synchronized reconfiguration indicating a PSCell change is received; an LTM cell handover command for PSCell handover is received; the PSCell change is successfully completed; or the PSCell handover is successfully completed.

[0116] Through method 600, the terminal device can stop evaluating conditional LTM cell handover when an MCG or SCG link fails, and continue the evaluation after the failure is recovered.

[0117] It should be understood that the operations in methods 400 to 600 correspond to the combination Figure 2 The operations described in Figure 3 are as follows, and therefore, for the sake of brevity, other details will not be repeated here. Example implementation of the device

[0118] Figure 7 This is a simplified block diagram of a device 700 suitable for implementing embodiments of the present disclosure. The device 700 can be considered as follows: Figure 1 Another example implementation of the terminal device 110 or network device 120 or 130 shown. Therefore, device 700 may be implemented at or as a part of the terminal device 110 or network device 120 or 130.

[0119] As shown in the figure, device 700 includes a processor 710, a memory 720 coupled to the processor 710, a suitable transceiver 740 coupled to the processor 710, and a communication interface coupled to the transceiver 740. The memory 710 stores at least a portion of a program 730. The transceiver 740 can be used for required bidirectional or unidirectional communication. The transceiver 740 may include at least one of a transmitter 742 or a receiver 744. The transmitter 742 and receiver 744 may be functional modules or physical entities. The transceiver 740 has at least one antenna to facilitate communication, but in practice, there may be multiple access nodes mentioned in this application. The communication interface can represent any interface required for communication with other network elements, such as the X2 / Xn interface for bidirectional communication between eNBs / gNBs, the S1 / NG interface for communication between the Mobility Management Entity (MME) / Access and Mobility Management Function (AMF) / SGW / UPF and the eNB / gNB, the Un interface for communication between the eNB / gNB and the Relay Node (RN), or the Uu interface for communication between the eNB / gNB and the terminal equipment.

[0120] Assuming program 730 includes program instructions that, when executed by the associated processor 710, enable device 700 to operate according to embodiments of this disclosure, as referenced herein. Figures 1 to 6 The embodiments described herein can be implemented by computer software executable by the processor 710 of device 700, or by hardware, or by a combination of software and hardware. The processor 710 can be configured to implement various embodiments of this disclosure. Furthermore, a combination of the processor 710 and the memory 720 can form a processing unit 750 suitable for implementing various embodiments of this disclosure.

[0121] Memory 720 can be of any type suitable for a local technology network and can be implemented using any suitable data storage technology, such as, as non-limiting examples, non-transitory computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. Although only memory 720 is illustrated in device 700, several physically different memory modules may exist in device 700. Processor 710 can be of any type suitable for a local technology network and, as non-limiting examples, may include one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 700 may have multiple processors, such as application-specific integrated circuit chips that are time-dependent on a clock synchronized with the main processor.

[0122] In some embodiments, a terminal device includes a circuit system configured to: determine that an execution condition for a candidate cell associated with a configuration for a conditional mobility procedure is met; and, based on the determination that the condition is met, skip a random access procedure during a conditional mobility procedure to a candidate cell, the condition including at least one of the following: a timing advance measurement for the candidate cell is configured for the terminal device, a timing advance maintained by the terminal device for the candidate cell or a timing advance group associated with the candidate cell is valid, or a configuration authorization is available for the candidate cell.

[0123] In some embodiments, a terminal device includes a circuit system configured to: determine that a process for reporting failures in a primary or secondary cell group is initiated; and to stop or suspend the evaluation of conditional cell handover in LTM.

[0124] As used herein, the term "circuit system" can refer to hardware circuitry and / or a combination of hardware circuitry and software. For example, a circuit system can be a combination of analog and / or digital hardware circuitry with software / firmware. As another example, a circuit system can be any part of a hardware processor with software, including (multiple) digital signal processors, software, and (multiple) memories, which work together to cause a device, such as a terminal device or a network device, to perform various functions. In yet another example, a circuit system can be hardware circuitry and / or a processor, such as a microprocessor or a portion thereof, which requires software / firmware to operate, but the software may be absent when operation is not required. As used herein, the term circuit system also encompasses an implementation of only hardware circuitry or (multiple) processors or a portion thereof and its accompanying software and / or firmware.

[0125] Generally, the various embodiments of this disclosure can be implemented using hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects can be implemented using hardware, while others can be implemented using firmware or software that can be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of this disclosure are illustrated and described as block diagrams, flowcharts, or using some other graphical representation, it should be understood that, as non-limiting examples, the blocks, apparatuses, systems, techniques, or methods described herein can be implemented using hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0126] This disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in a program module, which execute in a device targeting a real or virtual processor to perform the functions described above. Figures 1 to 6The process or method described herein. Typically, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform specific tasks or implement specific abstract data types. In various embodiments, the functionality of a program module can be combined or split among program modules as needed. The machine-executable instructions of a program module can be executed on a local or distributed device. In a distributed device, a program module can reside on both local and remote storage media.

[0127] Program code used to perform the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0128] The aforementioned program code may be embodied on a machine-readable medium, which may be any tangible medium capable of containing or storing a program for use by or in connection with an instruction execution system, apparatus, or device. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination thereof. More specific examples of machine-readable storage media will include electrical connections having one or more wires, portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0129] Furthermore, although operations are described in a specific order, this should not be construed as requiring the operations to be performed in the specific order shown or sequentially, or to perform all of the shown operations to obtain the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the foregoing discussion, these should not be construed as limiting the scope of this disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features described in the context of a single embodiment may also be implemented in combination in a single embodiment. Conversely, the various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0130] Although this disclosure is described in language specific to structural features and / or methodological actions, it should be understood that the disclosure as defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as exemplary forms of implementing the claims.

Claims

1. A terminal device, comprising: The processor is configured to cause the terminal device to: The execution conditions for determining the candidate cells associated with the configuration used in the conditional mobility procedure are met; as well as If a predetermined condition is met, the random access procedure is skipped during the conditional mobility procedure to the candidate cell, the condition including at least one of the following: Timing advance measurement for the candidate cells is configured for the terminal device. The timing advance maintained by the terminal device for the candidate cell or the timing advance group associated with the candidate cell is valid, or Configuration authorization can be applied to the candidate cells.

2. The terminal device according to claim 1, wherein the terminal device is further configured to: The timing advance is determined to be valid based on at least one of the following: The first signal measurement value of the candidate cell is valid when a timing advance command indicating the timing advance is received; the second signal measurement value of the candidate cell is valid when the validity of the timing advance is determined. The difference between the first signal measurement and the second signal measurement is less than a threshold difference; or The time alignment timer for the candidate cell or the timing advance group associated with the candidate cell is running.

3. The terminal device according to claim 2, wherein the terminal device is further configured to: Upon determining that the timing advance command has been received, perform at least one of the following operations: The timing advance command is applied to the candidate cell or the timing advance group associated with the candidate cell; Start or restart the time alignment timer; or Store the first signal measurement value.

4. The terminal device according to claim 2 or 3, wherein the terminal device is further configured to: The timing advance command is received from a first network device providing the serving cell or a second network device providing the candidate cell via a media access control element, wherein the media access control element includes at least one of the following: The identifier of the configuration used in the conditional mobility process; The identifier of the timing advance group associated with the candidate cell; A first timing advance command for controlling the timing adjustment amount to be applied, the first timing advance command having a first bit length; or A second timing advance command is used to control the timing adjustment amount to be applied, the second timing advance command having a second bit length greater than the first bit length.

5. The terminal device according to claim 2 or 3, wherein the terminal device is further configured to perform at least one of the following: The downlink information is received from the first network device providing the service cell, the downlink information including the identifier of the candidate cell and contention-free random access information; Send a random access preamble to the second network device providing the candidate cells; or Receive a random access response including the timing advance command from the first network device or the second network device.

6. The terminal device according to claim 2, wherein the terminal device is further configured to perform at least one of the following: Based on a first timeframe within a first time period before or after the second timeframe when the timing advance command is received, the first signal measurement value is determined to be valid; or The second signal measurement value is determined to be valid within a second time range, prior to the fourth time range in which the validity of the measurement is determined before the third time at which the terminal device completes the measurement of the second signal measurement value.

7. The terminal device according to claim 1, wherein the terminal device is further configured to perform at least one of the following: If the time interval between the determined timing and the timing of the configuration authorization is more than a third time range after the determined timing, it is determined that the configuration authorization cannot be used for the candidate cell. Based on determining that the time interval is below the third time range after the timing, it is determined that the configuration authorization can be used for the candidate cell; If the time alignment timer for the timing advance group associated with the candidate cell is not running at the time of the configuration authorization, it is determined that the configuration authorization is not available for the candidate cell; or Based on determining that the time alignment timer is running at the time of the configuration authorization, it is determined that the configuration authorization is available for the candidate cell.

8. The terminal device according to claim 1, wherein the terminal device is further configured to: If it is determined that the random access procedure has been skipped, perform at least one of the following operations: Apply the measured timing advance to the main timing advance group, and start or restart the time alignment timer for the main timing advance group; The maintained timing advance is applied to the primary timing advance group, and the time alignment timer for the primary timing advance group is set to be the same as the time alignment timer for the timing advance group associated with or for the candidate cell; or The maintained timing advance is applied to the main timing advance group, and the time alignment timer for the main timing advance group is started or restarted.

9. The terminal device according to claim 1, wherein the conditional mobility process comprises at least one of the following: Conditional switching (CHO) process; Mobility TM (LTM) cell handover procedures triggered by conditions Layer 1 or Layer 2; or Conditional Primary and Secondary Cell (PSCell) Change Process.

10. A terminal device, comprising: The processor is configured to cause the terminal device to: The process for reporting failures in the primary or secondary cell group is determined to be initiated. as well as Stop or pause the evaluation of conditional cell handover in mobility (LTM) triggered by Layer 1 or Layer 2.

11. The terminal device of claim 10, wherein the terminal device is configured to stop or suspend the evaluation for the conditional cell handover by: The radio resource control layer instructs the lower layers of the terminal equipment to stop or suspend assessments for primary cell handover and primary-secondary cell handover.

12. The terminal device of claim 10, wherein the process for reporting the failure in the primary cell group is initiated, and the terminal device is further configured to: Based on the determination that a condition is met, the evaluation for cell handover for the condition is initiated, resumed, or continued, wherein the condition includes at least one of the following: A handover command for changing the primary cell was received; An LTM cell handover command for primary cell handover was received; The primary cell change was successfully completed; or The primary cell handover was successfully completed.

13. The terminal device of claim 10, wherein the process for reporting the failure in the secondary cell group is initiated, and the terminal device is further configured to: Based on the determination that a condition is met, the evaluation for cell handover for the condition is initiated, resumed, or continued, wherein the condition includes at least one of the following: A radio resource control reconfiguration message with synchronization, indicating a change in primary and secondary cells, is received; An LTM cell handover command for primary / secondary cell handover was received; The change of primary and secondary cells was successfully completed; or The handover between the primary and secondary cells was successfully completed.

14. A method of communication, comprising: At the terminal device, the execution conditions for determining the candidate cells associated with the configuration used for the conditional mobility procedure are met; as well as If a predetermined condition is met, the random access procedure is skipped during the conditional mobility procedure to the candidate cell, the condition including at least one of the following: Timing advance measurement for the candidate cells is configured for the terminal device. The timing advance maintained by the terminal device for the candidate cell or the timing advance group associated with the candidate cell is valid, or Configuration authorization can be applied to the candidate cells.

15. The method of claim 14, further comprising: The timing advance is determined to be valid based on at least one of the following: The first signal measurement value of the candidate cell is valid when a timing advance command indicating the timing advance is received; the second signal measurement value of the candidate cell is valid when the validity of the timing advance is determined. The difference between the first signal measurement value and the second signal measurement value is lower than the threshold difference; or The time alignment timer for the candidate cell or the timing advance group associated with the candidate cell is running.

16. The method of claim 15, further comprising: Upon determining that the timing advance command has been received, perform at least one of the following operations: The timing advance command is applied to the candidate cell or the timing advance group associated with the candidate cell; Start or restart the time alignment timer; or Store the first signal measurement value.

17. The method according to claim 15 or 16, further comprising: The timing advance command is received from a first network device providing the serving cell or a second network device providing the candidate cell via a media access control element, wherein the media access control element includes at least one of the following: The identifier of the configuration used in the conditional mobility process; The identifier of the timing advance group associated with the candidate cell; A first timing advance command for controlling the timing adjustment amount to be applied, the first timing advance command having a first bit length; or A second timing advance command is used to control the timing adjustment amount to be applied, the second timing advance command having a second bit length greater than the first bit length.

18. The method of claim 15 or 16, further comprising at least one of the following: The downlink information is received from the first network device providing the service cell, the downlink information including the identifier of the candidate cell and contention-free random access information; Send a random access preamble to the second network device providing the candidate cells; or Receive a random access response including the timing advance command from the first network device or the second network device.

19. The method of claim 15, further comprising at least one of the following: Based on a first timeframe within a first time period before or after the second timeframe when the timing advance command is received, the first signal measurement value is determined to be valid; or The second signal measurement value is determined to be valid within a second time range, prior to the fourth time range in which the validity of the measurement is determined before the third time at which the terminal device completes the measurement of the second signal measurement value.

20. The method of claim 14, further comprising: If it is determined that the random access procedure has been skipped, perform at least one of the following operations: Apply the measured timing advance to the main timing advance group, and start or restart the time alignment timer for the main timing advance group; The maintained timing advance is applied to the primary timing advance group, and the time alignment timer for the primary timing advance group is set to be the same as the time alignment timer for the timing advance group associated with or for the candidate cell; or The maintained timing advance is applied to the main timing advance group, and the time alignment timer for the main timing advance group is started or restarted.

Images