Communication methods and communication devices

Abstract

The communication method and apparatus provided in this application relate to the field of communication. The method includes configuring execution conditions for a terminal device to obtain the TA value of a candidate cell by a network. By setting these execution conditions, the terminal device is triggered to obtain the TA value of the candidate cell when the conditions are met. This increases the probability that the terminal device obtains the TA value before performing a C-LTM handover to the candidate cell, thus enabling the terminal device to perform a C-LTM handover without a random access procedure with a high probability. This helps reduce the service interruption time of the terminal device during the cell handover process and improves communication reliability.

Description

Technical Field

[0001] This application relates to the field of communications, and more particularly to a communication method and a communication device. Background Technology

[0002] In mobile communication systems, a conditional mobility (LTM) process triggered by Layer 1 / Layer 2 is considered, called conditional-LTM (C-LTM). Compared to LTM, C-LTM allows the network side to send the cell handover execution conditions to the terminal device in advance. When the terminal device meets the cell handover execution conditions of the corresponding candidate cell, the terminal device initiates a C-LTM handover to the candidate cell.

[0003] If the terminal device has not obtained its timing advance (TA) value in the candidate cell before initiating a C-LTM handover to the candidate cell, the terminal device will perform a random access procedure to achieve the handover. During the cell handover process, the terminal device's services are interrupted, which makes the LTM mechanism's effect of reducing service interruption time during cell handover insignificant. Summary of the Invention

[0004] This application provides a communication method and a communication device, applicable to the field of communication. It can increase the probability that a terminal device obtains the TA value of a candidate cell before the execution conditions for cell handover of the corresponding candidate cell are met, thereby reducing service interruption time.

[0005] Firstly, a communication method is provided, including:

[0006] Receive first information, which is used to indicate a first execution condition, which is an execution condition for obtaining first advance time information, which is uplink time advance information of the terminal device in the candidate cell for cell handover; and obtain the first advance time information when the first execution condition is met.

[0007] In one possible implementation, the method can be executed by the terminal device or by a chip in the terminal device.

[0008] Optionally, the first information may be determined by a network device (such as a base station) and sent to the terminal device.

[0009] For example, the first-time advance information may include the TA value.

[0010] The communication method of this application involves the network configuring conditions (i.e., first execution conditions) for the terminal device to obtain the TA value in the candidate cell. This triggers the terminal device to obtain the TA value in the candidate cell when the conditions are met. Compared to the terminal device autonomously obtaining the TA value, setting conditions for the terminal to obtain the TA value through the network can trigger the terminal device to obtain the TA value in the candidate cell in a timely manner. This increases the probability that the terminal device obtains the TA value before performing C-LTM handover to the candidate cell, enabling the terminal device to perform C-LTM handover without random access procedures with a high probability. This helps reduce the service interruption time of the terminal device during the cell handover process and improves the reliability of communication.

[0011] In one possible implementation, the first execution condition may be determined by the network device (such as a base station) for the terminal device and configured by the network device for the terminal device via signaling; this application does not limit this. For example, the network device may send the first information to the terminal device via a radio resource control (RRC) reconfiguration message (or RRC message), that is, the first information is carried in the RRC reconfiguration message.

[0012] In one possible implementation, the first execution condition may include, but is not limited to, at least one of the following:

[0013] (1) The signal quality of the candidate cell is greater than that of the serving cell, and the deviation between the signal quality of the candidate cell and the signal quality of the serving cell is greater than or equal to the threshold 1.

[0014] (2) The signal quality of the serving cell is less than or equal to threshold 2 and the signal quality of the candidate cell is greater than or equal to threshold 3.

[0015] (3) The signal quality of the candidate cell is greater than or equal to threshold 3 (the threshold 3 is a specific example of the first threshold).

[0016] The implementation of these three methods can be found in the relevant description of S401 below, and will not be repeated here.

[0017] In the specific implementation process, after receiving the first information, the terminal device obtains the first advance information when the terminal device determines (or evaluates) that the signal quality of the serving cell and / or candidate cell meets the first execution condition.

[0018] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: determining that a second execution condition is met, the second execution condition being a handover condition for switching to a candidate cell; and, based on the first advance information, switching from the serving cell to the candidate cell.

[0019] Optionally, the second execution condition may be predefined by the protocol or configured by the network for the terminal device via signaling; this application does not impose any restrictions on this. For example, the network device may send second information to the terminal device, which is used to configure candidate cells and / or the second execution condition. Accordingly, the terminal device receives the second information and determines the second execution condition based on the second information.

[0020] In one possible implementation, the second execution condition may include, but is not limited to, at least one of the following:

[0021] (1) The signal quality of the candidate cell is greater than that of the serving cell, and the deviation between the signal quality of the candidate cell and the signal quality of the serving cell is greater than or equal to the threshold 4.

[0022] (2) The signal quality of the serving cell is less than or equal to threshold 5 and the signal quality of the candidate cell is greater than or equal to threshold 6.

[0023] (3) The signal quality of the candidate cell is greater than or equal to threshold 6 (threshold 6 is a specific example of the second threshold).

[0024] The specific second execution condition can be found in the relevant description below, and will not be repeated here for the sake of brevity.

[0025] To increase the probability of terminal devices performing the random access-free procedure, that is, to increase the probability of terminal devices obtaining first advance information before performing C-LTM handover to candidate cells, the network can set the first execution condition to be more lenient than the second execution condition, so that the first execution condition can be met before the second execution condition. In other words, the signal quality of candidate cells measured by the terminal device is more likely to meet the first execution condition, which can enable the terminal device to obtain first advance information before performing C-LTM handover to candidate cells.

[0026] In conjunction with the first aspect, in some implementations of the first aspect, the first execution condition includes the signal quality of the candidate cell being greater than or equal to a first threshold, and the second execution condition includes the signal quality of the candidate cell being greater than or equal to a second threshold, wherein the first threshold is less than the second threshold.

[0027] The statement that the signal quality of a candidate cell is greater than or equal to the first threshold can be replaced with the statement that the signal quality of a candidate cell is better than the first threshold. The statement that the signal quality of a candidate cell is greater than or equal to the second threshold can be replaced with the statement that the signal quality of a candidate cell is better than the second threshold.

[0028] This implementation can be replaced by the following: the signal quality of the candidate cell when the first execution condition is met is lower than the signal quality of the candidate cell when the second execution condition is met, or the signal quality of the candidate cell when the second execution condition is met is higher than the signal quality of the candidate cell when the first execution condition is met.

[0029] For example, the signal quality of a cell can be characterized by one or more of the following parameters:

[0030] Reference signal received power (RSRP), signal to interference plus noise ratio (SINR), reference signal received quality (RSRQ), or received signal strength indicator (RSSI).

[0031] It should be understood that if a larger parameter (denoted as parameter A) used to characterize signal quality indicates worse signal quality, then the signal quality of the candidate cell being greater than or equal to the first threshold can be replaced with: if parameter A is less than or equal to the first threshold, the signal quality of the candidate cell being greater than or equal to the second threshold can be replaced with: if parameter A is less than or equal to the second threshold, the signal quality of the candidate cell is lower than the signal quality of the candidate cell satisfying the first execution condition. This can be replaced with: if parameter A of the candidate cell measured by the terminal device when the first execution condition is met is greater than the parameter A of the candidate cell measured by the terminal device when the second execution condition is met.

[0032] For example, the first execution condition being more lenient than the second execution condition can satisfy at least one of the following:

[0033] (1) Threshold 1 is less than threshold 4.

[0034] (2) Threshold 2 is greater than threshold 5.

[0035] (3) Threshold 3 is less than threshold 6 (or understood as the first threshold is less than the second threshold).

[0036] It should be understood that at least one of the above thresholds 1 to 6 may be predefined by the protocol or configured by the network for the terminal device, and this application does not impose any restrictions on this.

[0037] According to the above scheme, if at least one of the first execution condition and the second execution condition is met, it is highly likely that the signal quality of the candidate cell measured by the terminal device can meet the first execution condition before the second execution condition is met. This allows the terminal device to obtain the first advance information earlier than the terminal device performs the handover to the candidate cell, and the probability of the terminal device performing the random access-free process during the C-LTM handover to the candidate cell is higher.

[0038] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: upon obtaining the first advance information, starting a first timer, wherein the first advance information is valid during the operation of the first timer.

[0039] Optionally, the runtime of the first timer can be predefined by the protocol, or it can be configured by the network for the terminal device via signaling; this application does not impose any restrictions on this.

[0040] For example, in some implementations of the first aspect, the first information may also include the runtime of the first timer, and the serving base station may indicate the runtime of the first timer to the terminal device through the first information.

[0041] Furthermore, in conjunction with the first aspect, in some implementations of the first aspect, switching from the serving cell to the candidate cell based on the first advance information includes: if the first timer has not expired, switching from the serving cell to the candidate cell based on the first advance information.

[0042] According to the above scheme, the terminal device can perform handover to the candidate cell when the first advance information is valid. This increases the probability that the terminal device will perform the random access-free process during the C-LTM handover to the candidate cell, avoids the situation where the cell handover fails due to the failure of the first advance information, and improves the reliability of cell handover.

[0043] Optionally, obtaining first-hand advance information may include, but is not limited to, the following methods.

[0044] Method 1: Receive the reference signal of the candidate cell; determine the reception time deviation information between the serving cell and the candidate cell based on the reference signal; determine the first time advance information based on the time advance information and reception time deviation information of the serving cell.

[0045] The reference signal for candidate cells can be, for example, a synchronization signal block (SSB). The specific process for determining this first advance information can be found in the relevant description below, and will not be elaborated upon here.

[0046] Method 2: Send a random access request to the candidate cell. Further, receive the first advance information from the serving cell of the terminal device.

[0047] Optionally, the random access request information may include a random access preamble, which may be specified by the candidate base station for the terminal device and forwarded to the terminal device by the serving base station. The specific process by which the terminal device obtains this advance information can be found in the relevant description below, and will not be elaborated here.

[0048] According to method 1 and / or method 2 described above, the terminal device can obtain the first advance information when the first execution condition is met. However, it should be understood that the process of obtaining the first advance information described above is merely an exemplary description for the purpose of understanding this application and is not a specific limitation of this application. In actual applications, the terminal device can also determine the first advance information through other implementation methods, and this application does not impose any restrictions on this.

[0049] In conjunction with the first aspect, in some implementations of the first aspect, the first information is also used to configure random access channel resources for carrying the random access request information.

[0050] Optionally, the random access channel resource may indicate a dedicated RACH resource for obtaining timing advance information.

[0051] According to the above scheme, if the first execution condition is met, the terminal device can use the random access channel resource to send random access request information to the candidate cell in order to obtain the first advance information.

[0052] Secondly, it provides another communication method, including:

[0053] First information is determined, which is used to indicate a first execution condition, which is an execution condition for obtaining first advance time information, which is the uplink advance time information of the terminal device in the candidate cell for cell handover; the first information is sent to the terminal device.

[0054] In one possible implementation, the method can be executed by a network device or by a chip within the network device.

[0055] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: sending second information to the terminal device, the second information being used to configure candidate cells and / or second execution conditions, the second execution conditions being handover conditions for handover to candidate cells.

[0056] In conjunction with the second aspect, in some implementations of the second aspect, the first information is also used to indicate the runtime of the first timer, the runtime of the first timer being the effective duration of the first time advance information.

[0057] In conjunction with the second aspect, in some implementations of the second aspect, the first execution condition includes that the signal quality of the candidate cell is greater than or equal to a first threshold; the second execution condition includes that the signal quality of the candidate cell is greater than or equal to a second threshold, wherein the first threshold is less than the second threshold.

[0058] Optionally, the first execution condition and / or the second execution condition may also include other implementation methods, as detailed in the first aspect’s description of the first and second execution conditions, which will not be repeated here.

[0059] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: receiving first advance information from candidate cells; and sending the first advance information to the terminal device.

[0060] That is, when the terminal device obtains the first advance information by sending random access request information to the candidate cell, the base station managing the candidate cell (i.e., the candidate base station in the following text) can send the first advance information to the base station managing the serving cell (i.e., the serving base station in the following text), and the serving base station will forward the first advance information to the terminal device.

[0061] In conjunction with the second aspect, in some implementations of the second aspect, the first information is also used to configure random access channel resources for carrying random access request information, which is used to obtain first time advance information.

[0062] Thirdly, a communication apparatus is provided for performing the method in any of the possible implementations of the first and second aspects described above. Specifically, the apparatus includes a module for performing the method in any of the possible implementations of the first and second aspects described above.

[0063] Fourthly, embodiments of this application provide yet another communication device, including a processor coupled to a memory, which can be used to execute instructions in the memory to implement the method in any of the possible implementations of the first or second aspect described above. Optionally, the device further includes a memory. Optionally, the device further includes a communication interface, to which the processor is coupled.

[0064] In one implementation, the device is a terminal device. When the device is a terminal device, the aforementioned communication interface can be a transceiver, or an input / output interface.

[0065] In another implementation, the device is a chip integrated into the terminal device. When the device is a chip integrated into the terminal device, the aforementioned communication interface can be an input / output interface.

[0066] Fifthly, a processor is provided, comprising: an input circuit, an output circuit, and a processing circuit. The processing circuit is used to receive signals through the input circuit and transmit signals through the output circuit, causing the processor to execute the method in any possible implementation of the first or second aspect described above.

[0067] In the specific implementation process, the processor can be a chip, the input circuit can be an input pin, the output circuit can be an output pin, and the processing circuit can be a transistor, gate circuit, flip-flop, and various logic circuits. The input signal received by the input circuit can be received and input by, for example, but not limited to, a receiver, and the signal output by the output circuit can be output to, for example, but not limited to, a transmitter and transmitted by the transmitter. Furthermore, the input circuit and the output circuit can be the same circuit, which is used as the input circuit and the output circuit at different times. This application does not limit the specific implementation of the processor and various circuits.

[0068] A sixth aspect provides a processing apparatus including a processor and a memory. The processor is configured to read instructions stored in the memory and to receive signals via a receiver and transmit signals via a transmitter to execute the method in any of the possible implementations of the first or second aspect described above.

[0069] Optionally, there may be one or more processors and one or more memories.

[0070] Alternatively, the memory can be integrated with the processor, or the memory can be set up separately from the processor.

[0071] In the specific implementation process, the memory can be a non-transitory memory, such as a read-only memory (ROM), which can be integrated on the same chip as the processor or set on different chips. The embodiments of this application do not limit the type of memory or the way the memory and processor are set.

[0072] It should be understood that the relevant data interaction process, such as sending instruction information, can be a process of outputting instruction information from the processor, and receiving capability information can be a process of the processor receiving input capability information. Specifically, the processed output data can be output to the transmitter, and the input data received by the processor can come from the receiver. Here, the transmitter and receiver can be collectively referred to as transceivers.

[0073] The processing device in the sixth aspect above can be a chip. The processor can be implemented in hardware or software. When implemented in hardware, the processor can be a logic circuit, integrated circuit, etc. When implemented in software, the processor can be a general-purpose processor that reads software code stored in memory. The memory can be integrated into the processor or located outside the processor and exist independently.

[0074] In a seventh aspect, a computer program product is provided, comprising: a computer program (also referred to as code or instructions) that, when executed, causes a computer to perform the method in any possible implementation of the first or second aspect described above.

[0075] Eighthly, a computer-readable storage medium is provided that stores a computer program (also referred to as code or instructions) that, when executed on a computer, causes the computer to perform the methods in any of the possible implementations of the first or second aspect described above.

[0076] It should be understood that the second to eighth aspects of this application correspond to the technical solutions of the first aspect of this application, and the beneficial effects achieved by each aspect and the corresponding feasible implementation are similar, and will not be repeated here. Attached Figure Description

[0077] Figure 1 This is a schematic diagram of a communication system used in an embodiment of this application;

[0078] Figure 2 A schematic diagram of the LTM switching process is shown;

[0079] Figure 3 A schematic diagram of the C-LTM handover process is shown;

[0080] Figure 4 A flowchart illustrating the first communication method provided in an embodiment of this application;

[0081] Figure 5 A flowchart illustrating the second communication method provided in this application embodiment;

[0082] Figure 6 A flowchart illustrating the third communication method provided in this application embodiment;

[0083] Figure 7 This is a schematic block diagram of a communication device provided in an embodiment of this application. Detailed Implementation

[0084] To facilitate understanding of the embodiments of this application, the following points will be explained first:

[0085] In the embodiments of this application, "instruction" may include direct instruction, indirect instruction, explicit instruction, and implicit instruction. When describing a certain instruction information for indicating A, it can be understood that the instruction information carries A, directly indicates A, or indirectly indicates A.

[0086] In this embodiment of the application, " / " can indicate that the objects before and after are in an "or" relationship. For example, A / B can mean A or B. "And / or" can be used to describe three relationships between the related objects. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural.

[0087] In the embodiments of this application, "at least one" means one or more, and "more than one" means two or more, such as three, four or more. Similar expressions (such as at least one, at least one, etc.) are analogous. "At least one of the following," "one or more of the following," or similar expressions refer to any combination of these items, which may include only a single item or a combination of multiple items. For example, at least one of a, b, or c can represent: a, or b, or c; a and b; or a and c; or b and c; or a, b, and c. Where a, b, and c can be single or multiple.

[0088] In this embodiment of the application, for the convenience of describing the technical solution of the embodiment of the application, the terms "first" and "second" may be used for distinction. The terms "first" and "second" do not limit the quantity or execution order, and the terms "first" and "second" are not necessarily different.

[0089] In this application, the words "exemplary," "example," or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary," "example," or "for example" should not be construed as being more preferred or advantageous than other embodiments or designs. The use of words such as "exemplary," "example," or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0090] In this embodiment, "sending information / data" only indicates the direction of information / data transmission, including direct transmission via the device's communication interface (such as an air interface). "Sending" can also be understood as the "output" of the module interface. "Sending" can include indirect transmission by the processing unit through the communication interface, that is, after the processing unit outputs information / data through the module interface, it is transmitted to the device's communication interface and then sent out. "Receiving information / data" only indicates the direction of information / data transmission, including direct reception via the communication interface. "Receiving" can also be understood as the "input" of the module interface. "Receiving information / data" can include indirect reception by the processing unit through the communication interface, that is, after the communication interface receives information / data, it is transmitted to the module interface of the processing unit and then input to the processing unit. "Sending information / data to... (such as a terminal)" can be understood as the destination of the information being the terminal. It can include sending information / data directly or indirectly to the terminal. "Receiving information / data from... (such as a terminal)" can be understood as the source of the information being the terminal, and can include receiving information / data directly or indirectly from the terminal. Information / data may undergo necessary processing, such as format changes, between the source and destination, but the destination can understand the valid information / data from the source. Similar statements in this application can be understood in a similar way, and will not be repeated here.

[0091] The technical solutions of this application can be applied to various communication systems, such as Long Term Evolution (LTE) systems, 5th Generation (5G) communication systems, satellite communication systems, Wireless Fidelity (WiFi) systems, and the solutions provided in this application can also be applied to future communication systems or other communication systems. This application does not limit these applications.

[0092] The terminal equipment in this application embodiment can also be referred to as: user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent, or user device, etc.

[0093] Terminal devices can be devices that provide voice / data connectivity to users, such as handheld devices with wireless connectivity, in-vehicle devices, etc. Currently, examples of terminal devices include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving vehicles, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to wireless modems, in-vehicle devices, wearable devices, terminal devices in 5G networks, or future public land mobile communication networks. This application does not limit the scope to terminal devices in a network (PLMN), etc.

[0094] The network equipment involved in this application can be a device that communicates with terminal devices. This network equipment can also be called an access network device or a wireless access network device. It can be a transmission reception point (TRP), an evolved NodeB (eNB or eNodeB) in an LTE system, a home base station (e.g., home evolved NodeB or home Node B, HNB), a base band unit (BBU), or a radio controller in a cloud radio access network (CRAN) scenario. Alternatively, the network equipment can be a relay station, access point, vehicle-mounted equipment, wearable devices, or network equipment in a 5G network or a network equipment in a future evolved PLMN network. It can also be an access point (AP) in a WLAN, or a gNB in ​​an NR system. The above-mentioned network equipment can also be a city base station, micro base station, pico base station, femtobase station, etc. This application does not limit this.

[0095] In a network architecture, network devices may include centralized unit (CU) nodes, distributed unit (DU) nodes, RAN devices including CU nodes and DU nodes, or RAN devices including control plane CU nodes (CU-CP nodes), user plane CU nodes (CU-UP nodes), and DU nodes.

[0096] Network equipment provides services to cells. Terminal devices communicate with cells through transmission resources (e.g., frequency domain resources, or spectrum resources) allocated by the network equipment. The cell can belong to a macro base station (e.g., macro eNB or macro gNB) or to a base station corresponding to a small cell. Small cells can include: metrocell, microcell, pico cell, femto cell, etc. These small cells have the characteristics of small coverage area and low transmission power, and are suitable for providing high-speed data transmission services.

[0097] To facilitate understanding of the embodiments of this application, firstly, in conjunction with Figure 1 The communication system applicable to the embodiments of this application will be described in detail.

[0098] Figure 1 An embodiment of the present application is illustrated, representing a communication system 100. The communication system 100 may include at least one network device, such as... Figure 1The network device 110 shown; the communication system 100 may also include at least one terminal device, such as Figure 1 The terminal device 120 shown. The network device 110 and the terminal device 120 can communicate via a wireless link.

[0099] Figure 1 An exemplary network device 110 and a terminal device 120 are shown. Optionally, the communication system 100 may also include multiple network devices and / or multiple terminal devices.

[0100] The aforementioned communication devices, such as Figure 1 The network device 110 or terminal device 120 can be configured with multiple antennas. These multiple antennas may include at least one transmitting antenna for transmitting signals and at least one receiving antenna for receiving signals. Additionally, each communication device also includes a transmitter chain and a receiver chain, which, as will be understood by those skilled in the art, may include multiple components (e.g., processors, modulators, multiplexers, demodulators, demultiplexers, or antennas) related to signal transmission and reception. Therefore, network device 110 and terminal device 120 can communicate via multi-antenna technology.

[0101] Optionally, the communication system 100 may also include other network entities such as a network controller and a mobility management entity, but the embodiments of this application are not limited thereto.

[0102] It should be understood that Figure 1 The communication system 100 shown is merely an example. This application does not limit the specific architecture of the applicable system, nor does it limit the number and form of various devices contained in each communication system.

[0103] It should also be understood that in one possible implementation, network device 110 can act as a transmitter and terminal device 120 can act as a receiver, with network device 110 sending signals to terminal device 120; in another possible implementation, network device 110 can act as a receiver and terminal device 120 can act as a transmitter, with terminal device 120 sending signals to network device 110.

[0104] To better understand the methods provided in the embodiments of this application, the relevant technologies and terms involved in this application will be briefly explained below.

[0105] 1. Layer 1 or Layer 2 triggered mobility (LTM)

[0106] Layer 1 (L1) can also be called the physical layer, and layer 2 (L2) can also be called the data link layer. The L2 layer includes the medium access control (MAC) sublayer.

[0107] Traditional cell handover (i.e., changing the serving cell for a terminal device) is triggered by measurements at the Radio Resource Control (RRC) layer and the change of serving cell is completed via RRC signaling. The RRC layer can also be referred to as Layer 3 (L3). In this handover process, L1 and L2 layers need to be reconfigured via L3, which can cause a significant delay in the handover process, resulting in prolonged service interruptions for the terminal device.

[0108] Release 18 (R-18) of the mobile communication standard introduced a handover mechanism based on L1 and L2, also known as the LTM mechanism. This mechanism uses L1 / L2 signaling to change the serving cell of a terminal device, helping to reduce handover latency and service interruption time. For easier understanding, the following section will combine... Figure 2 This section explains the LTM process.

[0109] like Figure 2 As shown, the LTM process can include one or more of the following four stages: LTM preparation, early synchronization, LTM cell switch execution, and LTM cell switch completion.

[0110] LTM preparation can be understood as the process by which the base station prepares resources for potential candidate cells before the handover operation begins, as detailed in S201 to S203.

[0111] S201, The terminal device sends a measurement report to the base station.

[0112] Measurement reports may include, for example, measurement results of signal quality between the terminal device and one or more neighboring cells, as measured by the terminal device.

[0113] Specifically, the terminal device is in RRC connected state (RRC_CONNECTED). When the terminal device is in RRC connected state, it can use uplink (UL) resources (such as the physical uplink shared channel (PUSCH)) to send the aforementioned measurement report containing the measurement results. Correspondingly, after receiving the measurement report from the terminal device, the base station can perform LTM candidate preparation based on the measurement report and the current network state. LTM candidate preparation can, for example, involve the base station determining parameters such as the signal quality of neighboring cells based on the measurement report, and the base station can select one or more neighboring cells with better signal quality as LTM candidate cells. For example, neighboring cells with better signal quality may include neighboring cells with signal quality greater than or equal to a signal quality threshold, and / or neighboring cells with signal quality greater than the serving cell's signal quality. This LTM candidate cell can also be simply referred to as a candidate cell, and this application does not limit this.

[0114] Furthermore, the base station can execute S202.

[0115] S202, the base station sends an RRC reconfiguration message to the terminal device.

[0116] Alternatively, RRC reconfiguration can also be called LTM candidate configuration. RRC reconfiguration messages can include configuration information for one or more candidate cells.

[0117] Accordingly, after receiving the LTM candidate configuration from the base station, the terminal device can save the configuration information of one or more candidate cells. Furthermore, the terminal device can execute S203, which involves sending an RRC reconfiguration complete message to the base station.

[0118] Accordingly, the base station can receive an RCC reconfiguration complete message from the terminal device to determine that the terminal device has received the configuration information of the one or more candidate cells.

[0119] Optionally, early synchronization can be performed between the terminal device and the base station, for example, it may include steps S204a and S204b as follows, which are optional steps.

[0120] S204a, the terminal device performs downlink (DL) synchronization with the candidate cell.

[0121] Specifically, this downlink synchronization process occurs before the terminal device receives a candidate cell handover command. The terminal device performs downlink synchronization with the candidate cells. For example, the transmission configuration indication (TCI) state of the candidate cells can be activated in advance before the candidate cells become the serving cells. This allows the terminal device to achieve downlink synchronization with the candidate cells, thereby speeding up the handover process to one of the candidate cells when a handover to a candidate cell is triggered.

[0122] S204b, the terminal device performs uplink synchronization (UL synchronization) with the candidate cell.

[0123] Specifically, the aforementioned RRC reconfiguration message may include parameters or configuration items for configuring early uplink synchronization, so that the terminal device can initiate an early uplink synchronization process with one or more candidate cells that are different from the current serving cell.

[0124] The early uplink synchronization process can specifically refer to the process by which the terminal device obtains the uplink timing advance (TA) of one or more candidate cells in advance, or it can also be called the early TA process. This early TA process can be triggered by a physical downlink control channel (PDCCH) order or implemented through TA measurements based on the terminal device indicated by the aforementioned RRC reconfiguration message.

[0125] In the implementation of PDCCH order triggering, the base station of the candidate cell calculates the TA value between itself and the terminal device, and can send this TA value to the base station of the serving cell. Furthermore, when triggering LTM cell handover, the serving cell sends an LTM cell handover command to the terminal device, which includes the TA value between the terminal device and the candidate cell.

[0126] The implementation of TA measurement based on terminal devices can also be called UE-based TA measurement. Specifically, the terminal device can perform TA measurement on candidate cells after receiving the RRC reconfiguration message from the base station. It should be understood that the specific time when the terminal device performs TA measurement depends on the implementation of the terminal device, and this application does not impose any restrictions on this.

[0127] LTM cell handover execution refers to the process by which a terminal device switches to a candidate cell based on a received LTM cell switch command (CSC), which may include, but is not limited to, the following steps S205, S206, and S207.

[0128] Specifically, after receiving the RRC reconfiguration message from the base station, the terminal device can perform L1 measurements on one or more candidate cells configured in the RRC reconfiguration message to obtain L1 measurement results. The terminal device then executes S205, which involves sending an L1 measurement report containing the L1 measurement results to the base station.

[0129] Accordingly, after receiving the L1 measurement report from the terminal device, the base station makes an LTM decision, which means that the base station decides to perform a handover to the candidate cell and executes S206.

[0130] S206, the base station sends an LTM cell handover command to the terminal device.

[0131] The base station can send the LTM cell handover command to the terminal device through the medium access control (MAC) control element (CE).

[0132] Correspondingly, after receiving the LTM cell handover command from the base station, the terminal device performs a cell handover, switching from the source cell to the target cell, that is, leaving the source cell and applying the configuration of the target cell.

[0133] Optionally, if the terminal device does not have a usable TA value (e.g., the cell handover command does not provide a valid TA value, and the terminal device itself does not have a usable TA value), the terminal device can perform LTM cell handover through S207, that is, the terminal device completes the handover to the candidate cell through a random access procedure.

[0134] Alternatively, if the terminal device has a usable TA, such as when the LTM cell handover command includes the TA value of the candidate cell, or when the terminal device obtains the TA value of the candidate cell through UE-based TA measurement before receiving the LTM cell handover command, the terminal device can execute an LTM procedure without a random access procedure. That is, the terminal device can perform a handover to the candidate cell without performing the random access procedure in S207, thereby enabling data transmission with the candidate cell.

[0135] The process of eliminating random access can also be called RACH-less, which will not be elaborated on further below.

[0136] S208, The handover of the terminal device to the candidate cell is complete (or it can also be called reconfiguration complete).

[0137] Optionally, the terminal device may send an RRC reconfiguration complete message to the base station to notify the base station that the terminal device has completed the handover to the candidate cell.

[0138] It should be understood that in the LTM process described above, the terminal device can obtain early synchronization of the candidate cell in advance, so as to quickly switch to the candidate cell after receiving the cell handover command. Furthermore, compared to the traditional cell handover process which sends the handover command via RRC messages, the LTM process sends the LTM cell handover command via MCE CE, which makes the handover process faster and reduces the interruption time of terminal device services during the handover process.

[0139] 2. Conditional LTM (C-LTM)

[0140] Mobile communication standards also consider introducing C-LTM. Compared to LTM, C-LTM means that the base station can send the cell handover execution conditions of candidate cells to the terminal device in advance, and the terminal device does not need to execute S205 and S206. Instead, when the terminal device meets the cell handover execution conditions of the corresponding candidate cell, the terminal device initiates an LTM handover to the candidate cell. For ease of understanding, the following will combine... Figure 3 The C-LTM process is illustrated as an example.

[0141] like Figure 3 As shown, the C-LTM process may also include one or more of the four stages: LTM preparation, early synchronization, LTM cell handover execution, and LTM cell handover completion. The C-LTM process may include, but is not limited to, the following S301 to S306.

[0142] S301, the terminal device sends a measurement report to the base station.

[0143] Similar to the LTM process, the terminal device is also in RRC connection state before sending the measurement report to the base station. See the relevant description in S201 for details, which will not be repeated here.

[0144] Accordingly, after receiving the measurement report from the terminal device, the base station can prepare C-LTM candidates.

[0145] Furthermore, the base station can execute S302, that is, the base station sends an RRC reconfiguration message to the terminal device. This RRC reconfiguration message may include configuration information and execution conditions for one or more candidate cells. Specifically, the execution conditions may be cell handover execution conditions. For example, the cell handover execution conditions may be that the signal quality of the candidate cell is higher than the signal quality of the serving cell by a threshold 1, or that the signal quality of the serving cell is lower than a threshold 2 and the signal quality of the candidate cell is higher than a threshold 3. Thresholds 1, 2, and 3 can be predefined by the protocol, and this application does not impose any restrictions on them.

[0146] Accordingly, after receiving the RRC reconfiguration message from the base station, the terminal device can save the configuration information and execution conditions of one or more candidate cells. Furthermore, the terminal device can execute S303, which involves sending an RRC reconfiguration completion message to the base station.

[0147] Optionally, similar to the LTM process, the terminal device in the C-LTM process can also perform an early synchronization process with the base station, which may include, for example, steps S304a and S304b, which are optional steps.

[0148] S304a, the terminal device performs DL synchronization with the candidate cell.

[0149] S304b, the terminal device performs UL synchronization with the candidate cell.

[0150] It should be understood that the implementation of S304a and S304b is similar to that of S204a and S204b above. For details, please refer to the relevant descriptions of S204a and S204b, which will not be repeated here.

[0151] The LTM cell handover execution in the C-LTM process may include: the terminal equipment evaluating the execution conditions, that is, the terminal equipment evaluating whether the current serving cell and the candidate cell meet the execution conditions for cell handover. For example, the terminal equipment may evaluate whether the signal quality of the candidate cell is higher than the signal quality of the serving cell by a threshold 1, or the terminal equipment may evaluate whether the signal quality of the serving cell is lower than a threshold 2 and the signal quality of the candidate cell is higher than a threshold 3.

[0152] If the conditions for cell handover are met, the terminal device can initiate an LTM handover to the candidate cell, that is, the terminal device leaves the source cell and applies the configuration of the target cell (i.e., the terminal device disconnects from the source cell and performs a handover to the candidate cell).

[0153] S306, The terminal device has completed the handover to the LTM candidate cell.

[0154] Since the C-LTM process does not require network devices (such as base stations) to send cell handover commands to terminal devices, the network cannot determine when the terminal device will meet the execution conditions and initiate an LTM handover to a candidate cell.

[0155] If the conditions for handover to a candidate cell are met, and the terminal device has obtained a valid TA value for the candidate cell, the terminal device can execute a C-LTM procedure without a random access procedure to handover to the LTM candidate cell, thereby enabling data transmission with the LTM candidate cell. This helps reduce the latency caused by service interruption during the cell handover process.

[0156] However, if the conditions for handover to a candidate cell are met, but the terminal device has not yet obtained a valid TA value for the candidate cell, for example, because the terminal device has not yet performed the early uplink synchronization procedure (i.e., S304b) for the candidate cell, or because the terminal device has performed early uplink synchronization but has not yet obtained a valid TA value, or because the TA value obtained by the terminal device has expired (e.g., exceeded the TA validity period), then the terminal device needs to perform S305, that is, the terminal device performs a random access procedure to achieve LTM handover to the candidate cell. The entire random access procedure involves multiple steps and round-trip time, including the transmission of the random access preamble, the random access response, and the sending of the connection request message. Therefore, compared to handover without a random access procedure, the service interruption time for the terminal device during the handover process is longer, failing to achieve the design intention of the LTM mechanism to reduce the service interruption time for the terminal device during the handover process.

[0157] To improve the performance of C-LTM handover without random access procedures by terminal devices and achieve the design goal of reducing service interruption time during handover, this application proposes that the network configure execution conditions for the terminal device to obtain the TA value in the candidate cell. By setting these conditions, the terminal device is triggered to obtain the TA value in the candidate cell when these conditions are met. This increases the probability that the terminal device obtains the TA value before proceeding with the C-LTM handover to the candidate cell, thus significantly increasing the likelihood of successful C-LTM handover without random access procedures. This helps reduce service interruption time during cell handover and improves communication reliability.

[0158] The following is combined with Figures 4 to 6This application provides a detailed description of the communication method. The embodiments shown in this application illustrate the communication method provided by this application from the perspective of device interaction. The specific forms and numbers of the devices shown are merely examples and should not constitute any limitation on the implementation of the method provided in this application. In each embodiment, the function of the base station (serving base station / candidate base station) can be implemented by the access network equipment described above. Alternatively, it can be implemented by a module configurable in the base station. When the executing entity is a terminal device or a module in the base station, receiving / transmitting can be understood as input / output, that is, the module communicates with other modules or components of the terminal device or base station. Furthermore, the operation performed by a single executing entity can also be divided into operations performed by multiple executing entities, which can be logically and / or physically separated. For example, the operation performed by the base station can be divided into operations performed by at least one of CU, DU, RU, etc.

[0159] The communication method of the embodiments of this application will be described in detail below. Figure 4 As shown, the communication method 400 may include, but is not limited to, the following S401, S402 and S403.

[0160] S401, the network device determines first information, which is used to indicate a first execution condition. The first execution condition is the execution condition for obtaining first advance time information, which is the uplink advance time information of the terminal device in the candidate cell for cell handover.

[0161] The network equipment can be the network equipment of the serving cell of the management terminal equipment, such as the base station of the serving cell of the management terminal equipment. The base station of the serving cell of the management terminal equipment can also be called the source base station, the serving base station, or the serving gNB, etc. The first advance information can also be called the first TA information or the first TA value, etc., and this application does not limit it.

[0162] The first execution condition is the condition for the terminal device to obtain the first advance information. That is, if the first execution condition is met, the terminal device can obtain the first advance information.

[0163] The first execution condition is related to the signal quality of the candidate cell. For example, the signal quality of the cell can be characterized by one or more of the following parameters:

[0164] Reference signal received power (RSRP), signal to interference plus noise ratio (SINR), reference signal received quality (RSRQ), or received signal strength indicator (RSSI).

[0165] The implementation methods for the first execution condition may include, but are not limited to, the following implementation methods 1, 2, and 3:

[0166] Implementation method 1, the first execution condition includes that the signal quality of the candidate cell is greater than the signal quality of the serving cell, and the deviation between the signal quality of the candidate cell and the signal quality of the serving cell is greater than or equal to a threshold 1.

[0167] Alternatively, the first execution condition includes the candidate cell's signal quality being at least 1 higher than the serving cell's signal quality.

[0168] Optionally, the network device can determine the threshold 1 based on the measurement report reported by the terminal device.

[0169] After determining the first execution condition, the network device can determine the first information, which is used to indicate the first execution condition. For example, the first information may include indication information for indicating the threshold 1.

[0170] Threshold 1 can also be called threshold 1 or the first threshold, etc., and this application does not limit it in this way. Similarly, threshold 2 to threshold n in the following text can also be called threshold 2 to threshold n, or the second threshold to the nth threshold, etc., and will not be elaborated further in the following text.

[0171] Implementation method 2, the first execution condition includes the signal quality of the serving cell being less than or equal to threshold 2 and the signal quality of the candidate cell being greater than or equal to threshold 3.

[0172] That is, when the signal quality of the serving cell is less than or equal to threshold 2 and the signal quality of the candidate cell is greater than or equal to threshold 3, the terminal device obtains the first advance information of the candidate cell.

[0173] Threshold 2 can be less than or equal to threshold 3. Alternatively, threshold 2 can be greater than threshold 3. This application does not limit the relationship between threshold 2 and threshold 3.

[0174] Similar to implementation method 1, after determining the first execution condition, the network device can determine the first information, which is used to indicate the first execution condition. For example, the first information may include indication information for indicating the threshold 2 and the threshold 3.

[0175] Implementation method 3, the first execution condition includes the signal quality of the candidate cell being greater than or equal to a threshold 3.

[0176] That is, when the signal quality of the candidate cell is greater than or equal to a threshold of 3, the terminal device obtains the first advance information of the candidate cell. In this third embodiment, the terminal device may disregard the signal quality of the serving cell and only obtain the first advance information of the candidate cell when the signal quality of the candidate cell meets the conditions.

[0177] Similar to implementation method 1, after determining the first execution condition, the network device can determine the first information, which is used to indicate the first execution condition. For example, the first information may include indication information for indicating the threshold 3.

[0178] According to embodiments 1 to 3 above, the terminal device can obtain first advance information when the first execution condition is met. Specifically, the first execution condition refers to which method in embodiments 1 to 3 can be predefined by the protocol. Alternatively, multiple methods can be predefined by the protocol, and the first information indicates the specific method used in the first execution condition. The threshold indicated by the first information is the threshold corresponding to that method.

[0179] For ease of distinction, the handover condition for a terminal device to switch to a candidate cell will be referred to as the second execution condition in the following text. That is, if the second execution condition is determined to be met, the terminal device can switch from the serving cell to the candidate cell based on the first advance information obtained. The second execution condition can be predefined by the protocol or configured by the network for the terminal device through signaling; this application does not impose any restrictions on this.

[0180] For example, the serving base station may send second information to the terminal device, which is used to configure candidate cells. For instance, the second information may include configuration information of the candidate cells (e.g., the identifier of the candidate cell), which is used by the terminal device to access the candidate cells. Alternatively, the second information may also be used to configure second execution conditions; for example, the second information may also include second execution conditions.

[0181] Optionally, the network device can send the second information to the terminal device via an RRC reconfiguration message (or an RRC message), that is, the second information is carried in the RRC reconfiguration message.

[0182] Optionally, the first and second information mentioned above can be transmitted in the same RRC reconfiguration message, or they can be transmitted through different RRC reconfiguration messages. This application does not impose any restrictions on this.

[0183] The specific implementation methods for the second execution condition may include, but are not limited to, the following methods 1, 2, and 3:

[0184] Method 1, the second execution condition includes that the signal quality of the candidate cell is greater than the signal quality of the serving cell, and the deviation between the signal quality of the candidate cell and the signal quality of the serving cell is greater than or equal to the threshold 4.

[0185] Alternatively, the second execution condition includes the candidate cell's signal quality being at least 4 points higher than the serving cell's signal quality.

[0186] Optionally, the network device may determine the threshold 4 based on the measurement report reported by the terminal device, or the threshold 4 may be predefined by the protocol, which is not limited in this application.

[0187] After determining the second execution condition, the network device can determine the second information, which is used to indicate the second execution condition. For example, the second information may include indication information for indicating the threshold 4.

[0188] Method 2, the second execution condition includes the signal quality of the serving cell being less than or equal to threshold 5 and the signal quality of the candidate cell being greater than or equal to threshold 6.

[0189] That is, if the signal quality of the serving cell is less than or equal to threshold 5 and the signal quality of the candidate cell is greater than or equal to threshold 6, the terminal device performs C-LTM handover to the candidate cell.

[0190] Similar to method 1, after determining the second execution condition, the network device can determine the second information, which is used to indicate the second execution condition. For example, the second information may include indication information for indicating the threshold 5 and the threshold 6.

[0191] Threshold 5 can be less than or equal to threshold 6. Alternatively, threshold 5 can be greater than threshold 6. This application does not limit the relationship between threshold 5 and threshold 6.

[0192] Method 3, the second execution condition includes the signal quality of the candidate cell being greater than or equal to the threshold 6.

[0193] That is, if the signal quality of the candidate cell is greater than or equal to a threshold of 6, the terminal device performs a C-LTM handover to the candidate cell. In this method 3, the terminal device may disregard the signal quality of the serving cell and only perform a C-LTM handover to the candidate cell if the signal quality of the candidate cell meets the requirements.

[0194] Optionally, at least one of the thresholds 4, 5 and 6 mentioned above may be predefined by the protocol, or may be configured by the network for the terminal device through signaling (such as configuring the terminal device through the second information), and this application does not impose any restrictions on this.

[0195] It should be noted that the above-described implementation of the second execution condition is merely an exemplary description for better understanding the embodiments of this application and is not a specific limitation of this application. In practical applications, the second execution condition may vary depending on specific needs and application scenarios. Specifically, it can be determined according to the execution conditions of cell handover in the C-LTM process defined in the protocol, and this application does not impose any restrictions on this.

[0196] It should be understood that, in order to increase the probability of the terminal device performing the random access-free procedure, that is, to increase the probability of the terminal device obtaining the first advance information before performing C-LTM handover to the candidate cell, when the network device determines the first information (or understand it as the first execution condition), it should also be considered that the execution condition for the terminal device to obtain the first advance information should be more lenient than the execution condition for the terminal device to perform cell handover (that is, the first execution condition is more lenient than the second execution condition), or it can be understood that the execution condition for the terminal device to perform cell handover is more stringent than the execution condition for the terminal device to obtain the first advance information (that is, the second execution condition is more stringent than the first execution condition). In this way, compared with the second execution condition, the signal quality of the candidate cell measured by the terminal device is more likely to meet the first execution condition, so that the terminal device can obtain the first advance information before performing C-LTM handover to the candidate cell.

[0197] In one optional implementation, the first execution condition includes the signal quality of the candidate cell being greater than or equal to a first threshold, and the second execution condition includes the signal quality of the candidate cell being greater than or equal to a second threshold, wherein the first threshold is less than the second threshold.

[0198] The statement that the signal quality of a candidate cell is greater than or equal to the first threshold can be replaced with the statement that the signal quality of a candidate cell is better than the first threshold. The statement that the signal quality of a candidate cell is greater than or equal to the second threshold can be replaced with the statement that the signal quality of a candidate cell is better than the second threshold.

[0199] This implementation can be replaced by the following: the signal quality of the candidate cell when the first execution condition is met is lower than the signal quality of the candidate cell when the second execution condition is met, or the signal quality of the candidate cell when the second execution condition is met is higher than the signal quality of the candidate cell when the first execution condition is met.

[0200] For example, the signal quality of a cell can be characterized by one or more of the following parameters:

[0201] Reference signal received power (RSRP), signal to interference plus noise ratio (SINR), reference signal received quality (RSRQ), or received signal strength indicator (RSSI).

[0202] It should be understood that if a larger parameter (denoted as parameter A) used to characterize signal quality indicates worse signal quality, then the signal quality of the candidate cell being greater than or equal to the first threshold can be replaced with: if parameter A is less than or equal to the first threshold, the signal quality of the candidate cell being greater than or equal to the second threshold can be replaced with: if parameter A is less than or equal to the second threshold, the signal quality of the candidate cell is lower than the signal quality of the candidate cell satisfying the first execution condition. This can be replaced with: if parameter A of the candidate cell measured by the terminal device when the first execution condition is met is greater than the parameter A of the candidate cell measured by the terminal device when the second execution condition is met.

[0203] In order to achieve the first execution condition being more lenient than the second execution condition, when the network device determines the first information (or the first execution condition), the first execution condition and the second execution condition can satisfy at least one of the following:

[0204] (1) Threshold 1 is less than threshold 4 (or threshold 1 is lower than threshold 4).

[0205] In other words, in order to ensure that the terminal device obtains the first advance information before the terminal device performs C-LTM handover to the candidate cell, the threshold 1 corresponding to the first execution condition should be lower than the threshold 4 corresponding to the second execution condition.

[0206] Specifically, when threshold 1 is less than threshold 4, the first execution condition is more lenient than the second execution condition. The signal quality of the candidate cell measured by the terminal device is more likely to meet the first execution condition than the second. For example, if threshold 1 is 1 dB and threshold 4 is 3 dB, then the terminal device can acquire first advance information when the signal quality of the candidate cell is 1 dB higher than that of the serving cell, and can only perform C-LTM handover of the candidate cell when the signal quality of the candidate cell is 3 dB higher than that of the serving cell.

[0207] (2) Threshold 2 is greater than threshold 5 (or threshold 2 is higher than threshold 5).

[0208] Specifically, threshold 2 and threshold 5 are the thresholds for the signal quality of the terminal device in the serving cell corresponding to the first execution condition and the second execution condition, respectively. When threshold 2 is greater than threshold 5, it is easier for the signal quality of the terminal device in the serving cell to be lower than threshold 2 than lower than threshold 5. In other words, it is easier for the signal quality of the candidate cell measured by the terminal device to meet the first execution condition than to meet the second execution condition (that is, the first execution condition is more lenient than the second execution condition).

[0209] For example, assuming the initial signal quality of the terminal device in the serving cell is 25dB, threshold 2 is 20dB, and threshold 5 is 15dB, then the terminal device can obtain the first advance information when the signal quality in the serving cell is below 20dB, and can only perform C-LTM handover to the candidate cell when the signal quality in the serving cell is below 15dB. It can be seen that when threshold 2 is greater than threshold 5, obtaining the first advance information takes precedence over performing C-LTM handover to the candidate cell.

[0210] (3) Threshold 3 is less than threshold 6 (or threshold 3 is lower than threshold 6).

[0211] Specifically, threshold 3 and threshold 6 are the thresholds for the signal quality of the terminal device in the candidate cell corresponding to the first execution condition and the second execution condition, respectively. When threshold 3 is less than threshold 6, it is easier for the signal quality of the terminal device in the candidate cell to be greater than threshold 3 than greater than threshold 6. In other words, it is easier for the signal quality of the candidate cell measured by the terminal device to meet the first execution condition than to meet the second execution condition (that is, the first execution condition is more lenient than the second execution condition).

[0212] For example, assuming the initial signal quality of the terminal device in the candidate cell is 15dB, threshold 3 is 20dB, and threshold 6 is 25dB, then the terminal device can obtain the first advance information when the signal quality in the candidate cell is greater than 20dB, and can only perform C-LTM handover to the candidate cell when the signal quality in the candidate cell is greater than 25dB. It can be seen that when threshold 3 is greater than threshold 6, obtaining the first advance information takes precedence over performing C-LTM handover to the candidate cell.

[0213] It is understandable that if at least one of the first and second execution conditions is met, the network can satisfy the first execution condition before satisfying the second execution condition. This can likely enable the terminal device to obtain the first advance information earlier than the terminal device performs the handover to the candidate cell, making it more likely that the terminal device will perform the random access-free process during the C-LTM handover to the candidate cell, thus reducing the service interruption time of the terminal device during the cell handover process.

[0214] It should be noted that the above-described implementation method for determining the first execution condition by the network device is merely an exemplary description. In actual applications, other implementation methods can also be used to determine the first information (or the first execution condition) so that the first execution condition is less stringent than the second execution condition. For the sake of brevity, these will not be elaborated here.

[0215] It should also be understood that the specific implementation method used by the network device to determine the first information (or the first execution condition) so that the first execution condition is more lenient than the second execution condition may be predefined by the protocol, and this application does not impose any restrictions on this.

[0216] After determining the first piece of information, the network device can execute S402.

[0217] S402, the network device sends the first information to the terminal device.

[0218] Optionally, the network device can send the first information to the terminal device via an RRC reconfiguration message (or RRC message), that is, the first information is carried in the RRC reconfiguration message.

[0219] Accordingly, the terminal device receives first information from the network device, and based on this first information, the terminal device can determine the first execution condition.

[0220] Furthermore, the terminal device can execute S403.

[0221] S403, if the first execution condition is met, the terminal device obtains the first advance information.

[0222] Specifically, the terminal device can measure the signal quality of the serving cell and the candidate cell respectively, and determine whether the current network meets the first execution condition based on the signal quality of the serving cell and the candidate cell.

[0223] Optionally, the terminal device can obtain the signal quality of the serving cell and the candidate cell by measuring the reference signals of the serving cell and the candidate cell. The reference signal may be, for example, the synchronization signal block (SSB) of the serving cell and / or the candidate cell, or the channel state information reference signal (CSI-RS) of the serving cell and / or the candidate cell. This application does not limit this.

[0224] It should be understood that the period during which the terminal device measures the signal quality of the candidate cell and the serving cell (i.e., when the terminal device measures the signal quality of the candidate cell and the serving cell) can be predefined by the protocol or configured by the network for the terminal device through signaling. This application does not impose any restrictions on this.

[0225] Furthermore, if the terminal device measures the signal quality of the candidate cell (optionally, it may also include the signal quality of the serving cell) and the signal quality meets the first execution condition, the terminal device can obtain the first advance information.

[0226] Specifically, if the specific implementation of the first execution condition is the implementation 1 of the first execution condition mentioned above, when the signal quality of the candidate cell is higher than the signal quality of the serving cell by a threshold 1, the terminal device obtains the candidate cell advance information in the first time.

[0227] For example, assuming the threshold 1 is 1dB, when the terminal device evaluates that the signal quality of the candidate cell is 1dB higher than that of the serving cell after measuring the reference signal of the candidate cell and / or the serving cell, the terminal device obtains the first advance information of the candidate cell.

[0228] If the specific implementation of the first execution condition is the implementation 2 of the first execution condition described above, when the signal quality of the serving cell is less than or equal to threshold 2 and the signal quality of the candidate cell is greater than or equal to threshold 3, the terminal device obtains the first advance information of the candidate cell.

[0229] For example, assuming thresholds 2 and 3 are 20dB, when the terminal device evaluates the signal quality of the serving cell to be less than or equal to 20dB and the signal quality of the candidate cell to be greater than or equal to 20dB, the terminal device obtains the first advance information of the candidate cell.

[0230] If the specific implementation of the first execution condition is the implementation method 3 of the first execution condition described above, the terminal device obtains the first advance information of the candidate cell when the signal quality of the candidate cell is greater than or equal to the threshold 3.

[0231] The specific implementation method for a terminal device to obtain the first advance information can be predefined by the protocol, or it can be configured by the network for the terminal device through signaling (such as through first information or other information). For example, the terminal device can use a UE-based TA measurement implementation to obtain the first advance information, etc. This application does not limit this. For ease of understanding, the process of how the terminal device obtains the first advance information is further explained below. See Implementation Method 1 and Implementation Method 2 below for details.

[0232] In Implementation Method 1, the terminal device receives a reference signal from a candidate cell. Based on this reference signal, the terminal device determines the reception time deviation information between the serving cell and the candidate cell. The terminal device then determines first time advance information based on the time advance information and the reception time deviation information in the serving cell.

[0233] For ease of distinction, the base station that manages candidate cells will be referred to as candidate base station or candidate gNB in ​​the following text.

[0234] Specifically, the reference signal for a candidate cell can be, for example, an SSB (Secondary Support Module). A candidate base station can broadcast the SSB of that candidate cell in each cell. Correspondingly, the terminal device can detect the SSB broadcast by the candidate base station through cell search, thereby receiving the reference signal of that candidate cell. Alternatively, the reference signal for a candidate cell can also be a CSI-RS (Content Specific Information), which will not be elaborated upon here for simplicity.

[0235] The received timing deviation information can be the time deviation between the downlink timing of the serving cell and the downlink timing of the candidate cell obtained by the terminal device; it can also be called downlink timing deviation information. Specifically, the terminal device can receive the reference signal from the serving base station and the reference signal from the candidate base station to determine this timing deviation.

[0236] The terminal device can receive reference signals from the serving cell and candidate cells respectively. For example, if the reference signal is an SSB, the serving cell's radio frame synchronization is determined based on its SSB, and the candidate cell's radio frame synchronization is determined based on its SSB. The time deviation between radio frames with the same frame number from the serving cell and the candidate cell is the reception time deviation between the serving cell and the candidate cell. Taking frame #n as an example, n can be 0, 1, 2, etc. The reception time of frame #n from the serving cell is reception time 1 (denoted as T). DL_serving The reception time of frame #n of the candidate cell is reception time 2 (denoted as T). DL_candidate Based on the reception time 1 and reception time 2, the reception time deviation information (denoted as ΔT) is determined. DL For example, T DL_serving T DL_candidate and ΔT DL satisfy:

[0237] ΔT DL =T DL_candidate -T DL_serving .

[0238] The terminal device uses the time advance information (or second time advance information, denoted as TA) in the serving cell. serving ) and received time deviation information (i.e., ΔT) DL ) Determine the first advance information (denoted as TA)candidate ). Optionally, TA serving TA candidate and ΔT DL Satisfy the following formula:

[0239] TA candidate =TA serving +2ΔT DL .

[0240] Where, ΔT DL This can be understood as the downlink timing difference between the serving cell and the candidate cell, where the downlink timing difference between the serving cell and the candidate cell is ΔT. DL In this case, the difference between the uplink signal of the terminal device and the serving cell and the candidate cell is also ΔT. DL Then in calculating TA candidate It is necessary to consider twice the reception time deviation information.

[0241] According to the above implementation, the terminal device can determine the first timing advance information when the signal quality of the candidate cell measured by the terminal device meets the first execution condition. However, it should be understood that the above-described implementation method for determining the first timing advance information based on the reference signal of the candidate cell is only an exemplary description for the purpose of understanding the embodiments of this application, and is not a specific limitation of this application. In actual applications, the first timing advance information can also be determined through other implementation methods. Specifically, how the first timing advance information is determined based on the reference signal can be predefined by the protocol, or it can be configured by the network for the terminal device through signaling, or it can be pre-configured in the terminal device. This application does not limit this.

[0242] In implementation method 2, the terminal device sends a random access request to the candidate cell. Further, the terminal device receives first-moment advance information about the serving cell from the terminal device.

[0243] In this context, the terminal device sending a random access request to a candidate cell can be understood as the terminal device actively initiating uplink synchronization with the candidate cell in order to obtain the TA value of the candidate cell.

[0244] The random access request information may include a random access preamble, which may be specified by the candidate base station for the terminal device and forwarded to the terminal device by the serving base station. Specifically, the candidate base station may assign at least one random access preamble to the terminal device, and may send indication information to the serving base station, which indicates the at least one random access preamble. The serving base station then forwards this indication information to the terminal device.

[0245] Optionally, the indication information may be carried in the first information sent by the serving base station to the terminal device. However, this application is not limited to this; the indication information may also not be carried in the first information. For example, the indication information and the first information may be sent to the terminal device through different RRC reconfiguration messages (or RRC messages), and this application does not impose any restrictions on this.

[0246] Accordingly, the terminal device receives indication information from the serving base station, which indicates at least one random access preamble. If the first execution condition is met, the terminal device sends random access request information to the candidate base station, the random access request information including one of the at least one random access preamble. First timing advance information is obtained through this random access request information. Correspondingly, after receiving the random access request information from the terminal device, the candidate base station can determine the first timing advance information based on the random access request information. The candidate base station can then send the first timing advance information to the serving base station, which forwards the first timing advance information to the terminal device, enabling the terminal device to obtain the first timing advance information.

[0247] Optionally, the aforementioned indication information is also used to configure random access channel resources. Specifically, the random access preamble in the random access request information is carried on the random access channel (RACH) resource. This random access channel resource may indicate a dedicated RACH resource for obtaining time advance information. Under the condition that the first execution condition is met, the terminal device uses the dedicated RACH resource to send random access request information (or random access preamble) to the candidate cell.

[0248] Compared to the LTM implementation in R18, which triggers early uplink synchronization via a PDCCH order initiated by the network device (see previous description for details), the network device does not know when the terminal device will meet the first execution condition, thus failing to guarantee that the terminal device will obtain the first advance information before performing C-LTM handover to the candidate cell. In this embodiment, dedicated RACH resources are sent to the terminal device in advance, and when the first execution condition is met, the terminal device actively initiates early uplink synchronization with the candidate cell (i.e., implementation method 2 above) to obtain the first advance information. This increases the probability that the terminal device will obtain the first advance information before performing C-LTM handover to the candidate cell, thus increasing the probability that the terminal device will perform the random access-free process and helping to reduce the service interruption time during cell handover.

[0249] According to the above scheme, the terminal device can obtain first advance information if the signal quality of the candidate cell measured by the terminal device meets the first execution condition. Furthermore, the terminal device can also determine (evaluate) whether the network meets the second execution condition. If the terminal device determines that the second execution condition is met, the terminal device switches from the serving cell to the candidate cell based on the first advance information (that is, the terminal device switches to the candidate cell without a random access procedure).

[0250] For example, assuming threshold 1 is 1dB and threshold 4 is 3dB, if the terminal device previously determined that the signal quality of the candidate cell was 1dB higher than that of the serving cell after measuring the reference signal of the candidate cell and / or the serving cell, meaning that the terminal device determined that the signal quality of the candidate cell measured by the terminal device met the first execution condition, the terminal device would acquire the first advance information. Further, if the terminal device again determines that the signal quality of the candidate cell is 3dB higher than that of the serving cell after measuring the reference signal, then the terminal device determines that the second execution condition is met, and the terminal device can perform a C-LTM handover to the candidate cell without a random access procedure based on the first advance information.

[0251] Optionally, the C-LTM handover to the candidate cell without a random access procedure performed by the terminal device can be, for example, by the terminal device sending a cell handover completion message (or an RRC reconfiguration completion message) to the candidate cell to notify the network terminal device that the handover to the candidate cell has been completed.

[0252] It should be understood that the first advance information is the amount of time that the terminal device needs to advance before sending the uplink signal, used to compensate for the signal propagation delay and ensure that the uplink signal arrives within the base station's receiving window. If the terminal device moves or the environment changes, the propagation delay may change, so the first advance information is time-sensitive. Therefore, in order to make the first advance information used by the terminal device effective and improve the probability of the terminal device successfully performing C-LTM handover to the candidate cell, this application embodiment also proposes that: when the terminal device obtains the first advance information, the terminal device starts a first timer, and the first advance information is effective during the operation of the first timer.

[0253] The first timer, also known as the first TA valid timer, manages the validity period of the first time advance information. During the operation of the first timer, the terminal device can determine that the current first time advance information is valid (i.e., the first time advance information can be used for uplink transmission). If the first timer expires, the terminal device considers the first time advance information invalid and cannot be used for uplink transmission, requiring it to reacquire the time advance information of the candidate cell.

[0254] Optionally, the runtime of the first timer can be predefined by the protocol, or it can be configured by the network for the terminal device via signaling; this application does not impose any restrictions on this. For example, the first information may also include the runtime of the first timer, and the serving base station can indicate the runtime of the first timer to the terminal device through the first information.

[0255] In the specific implementation process, after the terminal device determines that the first execution condition is met and obtains the first advance time information, the terminal device simultaneously starts the first timer. Further, if the terminal device determines that the second execution condition is met and the first timer has not expired, the first advance time information is valid, and the terminal device can switch from the serving cell to the candidate cell based on this first advance time information.

[0256] Optionally, if the first timer times out when the terminal device determines that the second execution condition is met, the terminal device can access the candidate cell through a random access procedure. Alternatively, the terminal device can also reacquire new time advance information according to the implementation method for obtaining the first time advance information shown in the above embodiments, and access the candidate cell based on the new time advance information. This application does not impose any restrictions on this.

[0257] According to the above scheme, the terminal device can perform handover to the candidate cell when the first advance information is valid, which increases the probability of the terminal device performing the random access-free process during the C-LTM handover to the candidate cell and reduces the service interruption time of the terminal device during the cell handover process.

[0258] It should be understood that at least two of the following in the above text, namely the first execution condition, the runtime of the first timer, the random access channel resources used to carry the random access request information, and the configuration information of the candidate cell and the second execution condition indicated by the second information, can be indicated by the same RRC reconfiguration message, or can be indicated by different RRC reconfiguration messages respectively. The specific indication method can be predefined by the protocol, and this application does not impose any restrictions on it.

[0259] Figure 5 and Figure 6 The communication method shown is Figure 4 Specific examples of the embodiments shown are described below in conjunction with... Figure 5 and Figure 6 The communication method provided in this application is further explained from the perspective of the interaction between terminal equipment, serving base station and candidate base station. Figure 5 and Figure 6 The same parts as those shown in the embodiments can be referred to in Figure 4 The descriptions in the illustrated embodiments will not be repeated here.

[0260] like Figure 5 As shown, the communication method 500 includes the following steps:

[0261] S501, the serving base station sends an RRC reconfiguration message to the terminal device. The RRC reconfiguration message may include at least one of the following configuration information: candidate cell, C-LTM execution conditions, first execution conditions, and TA valid timer.

[0262] The configuration information used to configure candidate cells can also be called LTM candidate configuration, which may include information such as the identifier or frequency of the candidate cell. This application does not limit this.

[0263] The C-LTM execution condition refers to the condition under which the terminal device performs a C-LTM handover to the candidate cell. This C-LTM execution condition is a specific example of the second execution condition mentioned above. The first execution condition is the condition under which the terminal device obtains the first advance information. Figure 5 In the embodiment shown, the terminal device can obtain the first advance information by using UE-based TA measurement. The first execution condition can be understood as the execution condition for the terminal device to obtain the TA value (i.e., the first advance information) by using the UE-based TA measurement method. The first execution condition can be called the UE-based TA measurement execution condition.

[0264] For example, the execution condition for UE-based TA measurement can be that the signal quality of the candidate cell is greater than that of the serving cell, and the deviation between the signal quality of the candidate cell and the signal quality of the serving cell is greater than or equal to threshold 1; or the execution condition for UE-based TA measurement can be that the signal quality of the serving cell is less than or equal to threshold 2 and the signal quality of the candidate cell is greater than or equal to threshold 3; or the execution condition for UE-based TA measurement can also be that the signal quality of the candidate cell is greater than or equal to threshold 3. For details, please refer to the description of the first execution condition above, which will not be repeated here.

[0265] Similarly, the execution conditions for C-LTM can be found in the description of the second execution condition above, and will not be repeated here.

[0266] It should be understood that the above-mentioned UE-based TA measurement execution conditions should be more lenient than the C-LTM execution conditions. In this way, compared with the C-LTM execution conditions, the signal quality of the candidate cell measured by the terminal device is more likely to meet the UE-based TA measurement execution conditions. This helps the terminal device to obtain the time advance information of the candidate cell through the implementation of UE-based TA measurement before performing C-LTM handover to the candidate cell, thereby increasing the probability of the terminal device accessing the candidate cell through the random access procedure and reducing the service interruption time of the terminal device during the cell handover process.

[0267] The TA valid timer is a specific example of the first timer mentioned above. The configuration information of the TA valid timer may include, for example, the runtime of the TA valid timer. For details, please refer to the relevant description of the first timer mentioned above, which will not be repeated here.

[0268] Optionally, at least two of the configuration information used to configure candidate cells, C-LTM execution conditions, UE-based TA measurement execution conditions, and TA valid timers can be transmitted in the same RRC reconfiguration message or in different RRC reconfiguration messages. This application does not impose any restrictions on this.

[0269] Similar to the LTM and C-LTM procedures described above, before the serving base station sends the RRC reconfiguration message to the terminal device, the serving base station and candidate base stations can also perform C-LTM candidate preparation. For details on the C-LTM candidate preparation process, please refer to [link to relevant documentation]. Figure 2 and Figure 3 The relevant descriptions of the embodiments will not be repeated here.

[0270] Correspondingly, the terminal device receives an RRC reconfiguration message from the serving base station.

[0271] S502, The terminal device determines (or assesses) that the UE-based TA measurement execution conditions are met.

[0272] Optionally, the implementation of confirming whether the UE-based TA measurement execution conditions are met can refer to the implementation of the terminal device confirming whether the first execution condition is met described above, and will not be repeated here for the sake of brevity.

[0273] It should be noted that the terminal device does not begin to evaluate the signal quality of the candidate cell and the serving cell only after receiving the RRC reconfiguration message. The specific period for the terminal device to measure the signal quality of the candidate cell and the serving cell can be predefined by the protocol, or it can be configured by the network for the terminal device through signaling. This application does not impose any restrictions on this.

[0274] Furthermore, if the terminal device satisfies the above-mentioned UE-based TA measurement execution conditions by evaluating the signal quality of the candidate cell and the serving cell, the terminal device measures the downlink timing difference between the serving base station and the candidate base station (corresponding to the reception time deviation information mentioned above).

[0275] Specifically, the terminal device can receive a reference signal (such as SSB) from the serving base station to determine the radio frame synchronization of the serving cell. The terminal device can also receive a reference signal (such as SSB) from the candidate base station to determine the radio frame synchronization of the candidate cell. The downlink timing (DL timing) of the serving base station and the candidate base station can be the downlink timing for the same frame number of the serving cell and the candidate cell, respectively. The terminal device can determine the downlink timing difference based on the downlink timing of the same frame number of the serving cell and the candidate cell. The specific calculation process for this downlink timing difference can be found in the process of determining the reception time deviation information described above, and will not be repeated here.

[0276] S503, the terminal device calculates the TA value (i.e., the first time advance information) of the candidate cell based on the downlink timing difference and the time advance information of the serving base station (corresponding to the second time advance information mentioned above).

[0277] Alternatively, the calculation of the TA value for candidate cells can also refer to the TA calculation method described above. candidate The relevant descriptions will not be repeated here.

[0278] Optionally, while the terminal device obtains the TA value of the candidate cell, the terminal device can also execute S504, that is, the terminal device starts the TA valid timer. The implementation method of the terminal device starting the TA valid timer can be referred to the relevant description of the first timer above, and will not be repeated here.

[0279] S505, under the condition that the C-LTM execution conditions are met, the terminal device performs a C-LTM handover to the candidate cell without a random access procedure.

[0280] Optionally, in order to make the TA value of the candidate base station used by the terminal device during the random access-free procedure valid, S505 can also be replaced by: when the C-LTM execution conditions are met and the TA valid timer has not expired, the terminal device performs the C-LTM handover to the candidate cell during the random access-free procedure.

[0281] In this embodiment, the terminal device performs TA measurement to obtain the TA of the candidate base station when the UE-based TA measurement execution conditions are met. By designing the UE-based TA measurement execution conditions to be more lenient than the C-LTM execution conditions, the terminal device is likely to obtain the time advance information of the candidate cell through the implementation of UE-based TA measurement before performing C-LTM handover to the candidate cell. In other words, the probability of the terminal device accessing the candidate cell through the random access procedure is increased, and the service interruption time of the terminal device during the cell handover process is reduced.

[0282] like Figure 6 As shown, the communication method 600 includes the following steps:

[0283] S601, the serving base station sends an RRC reconfiguration message to the terminal device. The RRC reconfiguration message may include at least one of the following configuration information: candidate cell, C-LTM execution conditions, first execution conditions, dedicated RACH resources, and TA valid timer.

[0284] Among them, Figure 6 In the illustrated embodiment, the terminal device can actively initiate uplink synchronization to obtain the TA value (i.e., the first advance information) of the candidate cell. Therefore, the first execution condition can be called the uplink synchronization execution condition, which should be more lenient than the C-LTM execution condition.

[0285] If the signal quality of the candidate cell measured by the terminal device meets the uplink synchronization execution condition, the terminal device can actively initiate uplink synchronization using dedicated RACH resources to obtain the TA value of the candidate cell. For simplicity, the TA value of the candidate cell will be referred to as the candidate cell TA in the following text.

[0286] Optionally, at least two of the configuration information used to configure candidate cells, C-LTM execution conditions, uplink synchronization execution conditions, dedicated RACH resources, and TA valid timers can be transmitted in the same RRC reconfiguration message or in different RRC reconfiguration messages. This application does not impose any restrictions on this.

[0287] Similarly, before the serving base station sends the RCC reconfiguration message to the terminal device, the serving base station and the candidate base station perform C-LTM candidate preparation. For details on the C-LTM candidate preparation process, please refer to [link to relevant documentation]. Figure 2 and Figure 3 The relevant descriptions of the embodiments will not be repeated here.

[0288] Correspondingly, the terminal device receives an RRC reconfiguration message from the serving base station.

[0289] S602, the terminal device determines (or evaluates) that the uplink synchronization execution conditions are met, and the terminal device uses dedicated RACH resources to send a random access preamble to the candidate cell.

[0290] Optionally, the preamble can be specified by the candidate base station for the terminal device and forwarded to the terminal device by the serving base station.

[0291] In the specific implementation process, when the terminal device evaluates that the signal quality of the candidate base station and the serving base station meets the uplink synchronization execution conditions, the terminal device uses dedicated RACH resources to send a preamble to the candidate cell in order to initiate an uplink synchronization request to the candidate cell and obtain the candidate cell TA.

[0292] Accordingly, the candidate base station receives the preamble from the terminal device and executes S603.

[0293] S603, the candidate base station sends the candidate cell TA to the serving base station, and the serving base station forwards the candidate cell TA to the terminal device.

[0294] Optionally, after receiving the candidate cell TA from the candidate base station, the serving base station can forward the candidate cell TA to the terminal device via MAC CE.

[0295] Optionally, the serving base station can also send the LTM candidate configuration identifier to the terminal device via MAC CE. The LTM candidate configuration identifier is used to indicate the configuration information of the candidate cell corresponding to the candidate cell TA.

[0296] Correspondingly, the terminal device receives the candidate cell TA from the serving base station, which means that the terminal device obtains the valid TA value of the candidate cell.

[0297] Optionally, while the terminal device obtains the valid TA value of the candidate cell, the terminal device can also execute S604, that is, the terminal device starts the TA valid timer.

[0298] S605, under the condition that the C-LTM execution conditions are met, the terminal device performs a C-LTM handover to the candidate cell without a random access procedure.

[0299] Optionally, in order to make the TA value of the candidate base station used by the terminal device during the random access-free procedure valid, S605 can also be replaced by: when the C-LTM execution conditions are met and the TA valid timer has not expired, the terminal device performs the C-LTM handover to the candidate cell during the random access-free procedure.

[0300] In this embodiment, the terminal device actively initiates uplink synchronization to the candidate cell to obtain the TA of the candidate base station when the uplink synchronization execution conditions are met. By designing the uplink synchronization execution conditions to be more lenient than the C-LTM execution conditions, the terminal device is likely to obtain the candidate cell's time advance information through uplink synchronization before performing C-LTM handover to the candidate cell. This increases the probability that the terminal device can access the candidate cell through the random access procedure and reduces the service interruption time of the terminal device during cell handover.

[0301] The above text combined Figures 4 to 6 The communication method of the embodiments of this application is described in detail below, in conjunction with Figure 7 This application describes in detail the communication apparatus according to embodiments of the present application. The communication apparatus includes modules or units for performing each part of the above embodiments. The modules or units may be software, hardware, or a combination of software and hardware. The following is only a brief illustrative example of the communication apparatus; for details of the implementation, please refer to the description of the foregoing method embodiments, which will not be repeated below.

[0302] Figure 7 A schematic block diagram of a communication device 700 provided in an embodiment of this application is shown. The device 700 includes a processor 701 and a transceiver 702.

[0303] Optionally, the device 700 may further include a memory 703, wherein the memory 703 is used to store instructions. The processor 701, transceiver 702, and memory 703 communicate with each other via internal interconnection paths. The processor 701 executes the instructions stored in the memory 703 to control the transceiver 702 to transmit and / or receive signals.

[0304] It should be understood that the device 700 may specifically be a terminal device or a network device as described in the above embodiments, and may be used to execute the various steps and / or processes corresponding to the terminal device or network device in the above method embodiments. Optionally, the memory 703 may include a read-only memory and a random access memory, and provide instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. For example, the memory may also store device type information. The processor 701 may be used to execute instructions stored in the memory, and when the processor 701 executes instructions stored in the memory, the processor 701 is used to execute the various steps and / or processes of the above method embodiments. The transceiver 702 may include a transmitter and a receiver, the transmitter may be used to implement the various steps and / or processes corresponding to the transceiver for performing a transmitting action, and the receiver may be used to implement the various steps and / or processes corresponding to the transceiver for performing a receiving action.

[0305] In one possible implementation, the device 700 is used to implement the steps corresponding to the terminal device in the method 400 described above.

[0306] Transceiver 702 is used to receive first information, which is used to indicate a first execution condition. The first execution condition is the execution condition for obtaining first advance time information, which is the uplink advance time information of the terminal device in the candidate cell for cell handover.

[0307] Processor 701 is configured to acquire the first advance time information when the first execution condition is met.

[0308] Optionally, the processor 701 is further configured to determine that a second execution condition is met, the second execution condition being a handover condition for switching to the candidate cell; and to switch from the serving cell to the candidate cell based on the first advance information.

[0309] Optionally, the transceiver 702 is also configured to receive second information, which is used to configure the candidate cell and / or the second execution conditions.

[0310] Optionally, the processor 701 is further configured to start a first timer upon receiving the first advance information, wherein the first advance information is valid during the operation of the first timer.

[0311] Optionally, the processor 701 is also configured to, if the first timer has not expired, switch from the serving cell to the candidate cell based on the first advance time information.

[0312] Optionally, the first information may also be used to indicate the runtime of the first timer.

[0313] Optionally, the first execution condition includes the signal quality of the candidate cell being greater than or equal to a first threshold; the second execution condition includes the signal quality of the candidate cell being greater than or equal to a second threshold, wherein the first threshold is less than the second threshold.

[0314] Optionally, the transceiver 702 is further configured to receive a reference signal from the candidate cell. The processor 701 is further configured to determine, based on the reference signal, reception time deviation information between the serving cell and the candidate cell for the terminal device, and determine first time advance information based on the time advance information and reception time deviation information of the terminal device in the serving cell.

[0315] Optionally, the transceiver 702 is also configured to send random access request information to the candidate cell and receive the first advance information from the serving cell of the terminal device.

[0316] Optionally, the first information is also used to configure random access channel resources for carrying the random access request information.

[0317] In another possible implementation, the device 700 is used to implement the steps corresponding to the network device in the method 400 described above.

[0318] The processor 701 is configured to determine first information, which is used to indicate a first execution condition, wherein the first execution condition is an execution condition for obtaining first advance time information, and the first advance time information is uplink time advance information of the terminal device in the candidate cell for cell handover.

[0319] Transceiver 702 is used to send the first message.

[0320] Optionally, the transceiver 702 is also configured to transmit second information, which is used to configure the candidate cell and / or a second execution condition, the second execution condition being a handover condition for switching to the candidate cell.

[0321] Optionally, the first information is also used to indicate the runtime of the first timer, the runtime of the first timer being the effective duration of the first time advance information.

[0322] Optionally, the first execution condition includes the signal quality of the candidate cell being greater than or equal to a first threshold; the second execution condition includes the signal quality of the candidate cell being greater than or equal to a second threshold, wherein the first threshold is less than the second threshold.

[0323] Optionally, the transceiver 702 is also used to receive advance information from candidate cells.

[0324] Optionally, the transceiver 702 is also used to send advance information to the terminal device.

[0325] Optionally, the first information is further used to configure random access channel resources for carrying random access request information, which is used by the terminal device to obtain the first advance information.

[0326] In the embodiments of this application, Figure 7 The device 700 in the text can also be a chip, such as a SOC or a modem.

[0327] It should be understood that, in the embodiments of this application, the processor may be a central processing unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0328] In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software. The steps of the method disclosed in the embodiments of this application can be directly manifested as execution by a hardware processor, or as a combination of hardware and software modules within the processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor executes the instructions in the memory, combining them with its hardware to complete the steps of the above method. To avoid repetition, detailed descriptions are omitted here.

[0329] Some embodiments of this application provide a chip system applied to a terminal device. The chip system includes at least one processor and an interface for receiving instructions and transmitting them to the at least one processor. The at least one processor executes instructions to cause the terminal to perform the aforementioned communication method. The chip system may be a modem, or a system-on-a-chip (SoC) including a modem, and the aforementioned method may be implemented by a modem.

[0330] The modem can include a NAS (non-access stratum) layer, an RRC layer, a PDCP layer, an RLC layer, a MAC layer, and a PHY layer. Each of these layers can be a software module. The modem can interact with network devices via an antenna.

[0331] This application also provides a computer-readable storage medium for storing a computer program that implements the methods shown in the above-described method embodiments.

[0332] This application also provides a computer program product, which includes a computer program (also referred to as code or instructions). When the computer program is run on a computer, the computer can execute the methods shown in the above-described method embodiments.

[0333] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0334] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and modules described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0335] In the embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0336] The modules described as separate components may or may not be physically separate. Similarly, the components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0337] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0338] If a function is implemented as a software module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, or the parts that contribute to the prior art, or parts of the technical solutions, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0339] The above description is merely a specific embodiment of this application, but the protection scope of the embodiments of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application should be included within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the claims.

Claims

1. A communication method, characterized in that, include: Receive first information, the first information is used to indicate a first execution condition, the first execution condition is the execution condition of obtaining first time advance information, the first time advance information is the uplink time advance information of the terminal device in the candidate cell of cell handover; If the first execution condition is met, the first time advance information is obtained.

2. The method according to claim 1, characterized in that, The method further includes: The second execution condition is determined to be met, which is the handover condition for switching to the candidate cell; Based on the first advance information, the serving cell is switched to the candidate cell.

3. The method according to claim 2, characterized in that, The method further includes: Receive second information, which is used to configure the candidate cell and / or the second execution condition.

4. The method according to claim 2 or 3, characterized in that, The method further includes: Upon obtaining the first advance time information, a first timer is started, and the first advance time information is valid during the operation of the first timer; The step of switching from the serving cell to the candidate cell based on the first advance time information includes: If the first timer has not expired, the serving cell is switched to the candidate cell based on the first time advance information.

5. The method according to claim 4, characterized in that, The first information is also used to indicate the runtime of the first timer.

6. The method according to claim 4 or 5, characterized in that, The first execution condition includes that the signal quality of the candidate cell is greater than or equal to a first threshold; The second execution condition includes that the signal quality of the candidate cell is greater than or equal to a second threshold. Wherein, the first threshold is less than the second threshold.

7. The method according to any one of claims 1 to 6, characterized in that, The step of obtaining the first time advance information includes: Receive the reference signal of the candidate cell; Based on the reference signal, the receiving time deviation information of the terminal device between the serving cell and the candidate cell is determined; The first time advance information is determined based on the terminal device's time advance information and reception time deviation information in the serving cell.

8. The method according to any one of claims 1 to 7, characterized in that, The step of obtaining the first time advance information includes: Send random access request information to the candidate cell; Receive the first time advance information from the serving cell of the terminal device.

9. The method according to claim 8, characterized in that, The first information is also used to configure random access channel resources for carrying the random access request information.

10. A communication method, characterized in that, include: First information is determined, which is used to indicate a first execution condition. The first execution condition is the execution condition for the terminal device to obtain first advance time information. The first advance time information is the uplink time advance information of the terminal device in the candidate cell during cell handover. Send the first message.

11. The method according to claim 10, characterized in that, The method further includes: Send a second message, which is used to configure the candidate cell and / or a second execution condition, wherein the second execution condition is a handover condition for switching to the candidate cell.

12. The method according to claim 11, characterized in that, The first information is also used to indicate the runtime of the first timer, the runtime of the first timer being the effective duration of the first time advance information.

13. The method according to claim 11 or 12, characterized in that, The first execution condition includes that the signal quality of the candidate cell is greater than or equal to a first threshold; The second execution condition includes that the signal quality of the candidate cell is greater than or equal to a second threshold. Wherein, the first threshold is less than the second threshold.

14. The method according to any one of claims 1 to 13, characterized in that, The method further includes: Receive the first time advance information from the candidate cell; Send the first time advance information to the terminal device.

15. The method according to any one of claims 1 to 14, characterized in that, The first information is also used to configure random access channel resources for carrying random access request information, wherein the random access request information is used to obtain the first time advance information.

16. A communication device, characterized in that, Includes a processor, which is coupled to a memory; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the communication device to perform the method as described in any one of claims 1 to 9, or to perform the method as described in any one of claims 10 to 15.

17. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 9, or implements the method as described in any one of claims 10 to 15.

18. A communication device, characterized in that, It includes at least one processor and a communication interface, the communication interface and the at least one processor being interconnected via a line, the at least one processor being configured to run a computer program or instructions to perform the method as claimed in any one of claims 1 to 9, or to perform the method as claimed in any one of claims 10 to 15.

19. A computer program product, characterized in that, Includes a computer program that, when run, causes a computer to perform the method as described in any one of claims 1 to 9, or causes a computer to perform the method as described in any one of claims 10 to 15.

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