A communication method, apparatus and system

Abstract

A communication method, device and system, the method can be executed by a first network device, or also can be executed by a component (such as a processor, a chip or a chip system, etc.) of the first network device. In the method: the first network device determines that a terminal device will enter a first area, the first area is an area for the terminal device to switch from the first network device to a second network device, or the first area is an area for joint transmission of the first network device and the second network device; before the terminal device enters the first area, the first network device sends first indication information to the terminal device to indicate measurement of a first tracking reference signal of the second network device. Since the terminal device completes the measurement of the first tracking reference signal of the second network device before entering the first area, when the terminal device completes cell switching or joint transmission, the time offset and frequency offset can be compensated in time according to the measurement result of the first tracking reference signal, thereby improving the communication quality.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and in particular to a communication method, apparatus and system. Background Technology

[0002] In downlink communication between terminal devices and network devices, on the one hand, there is an air interface transmission delay between the network device sending the downlink signal and the terminal device receiving it. The estimated air interface transmission delay by the terminal device differs from the actual air interface transmission delay, meaning that the terminal device and network device are not synchronized. This reduces the demodulation performance of the downlink signal, thus lowering communication quality. On the other hand, when the terminal device is moving rapidly, such as in high-speed rail or highway communication scenarios, the propagation path difference between the network device and the terminal device changes. Therefore, the downlink signal sent by the network device is affected by the Doppler effect during transmission, resulting in a Doppler frequency offset (or simply frequency offset) when the downlink signal reaches the terminal device. This also reduces the demodulation performance of the downlink signal, thus lowering communication quality. Currently, terminal devices can compensate for the time offset caused by air interface transmission delay and the frequency offset caused by the Doppler effect by measuring tracking reference signals, such as tracking reference signals (TRS) or synchronization signals and physical broadcast channel blocks (SSBs).

[0003] The process by which a terminal device compensates for time and frequency offsets by measuring the tracking reference signal is as follows: After the terminal device performs a cell handover, the target network device configures time and frequency resources to carry the tracking reference signal for the terminal device; the target network device broadcasts the tracking reference signal and sends Media Access Control-Control Element (MAC-CE) signaling to the terminal device; the terminal device receives the tracking reference signal and the MAC-CE signaling, which instructs the measurement of the tracking reference signal; the terminal device measures the tracking reference signal and obtains the measurement result; the target network device sends downlink control information (DCI) signaling and downlink signals to the terminal device; the terminal device receives the DCI signaling and downlink signals, which instructs the demodulation of the downlink signals based on the measurement result; the terminal device demodulates the downlink signals based on the measurement result.

[0004] When a terminal device is moving rapidly and frequently performs cell handovers, it needs to track time and frequency offsets in a timely manner to ensure communication quality. However, in the initial stage after a cell handover, the terminal device must wait to receive MAC-CE signaling from the target network device before it can begin measuring the tracking reference signal. During this waiting period, if the terminal device receives a downlink signal from the target network device, it will directly demodulate the downlink signal. At this time, the terminal device has not yet measured the tracking reference signal; that is, it has not yet compensated for the time offset caused by air interface transmission delay and the frequency offset caused by the Doppler effect. Therefore, this affects the demodulation performance of the downlink signal and degrades communication quality. Summary of the Invention

[0005] This application provides a communication method, apparatus, and system for timely compensation of time offset and frequency offset, thereby improving communication quality.

[0006] In a first aspect, embodiments of this application provide a communication method, which can be executed by a first network device or by a component of the first network device (such as a processor, chip, or chip system). In this method: the first network device determines that a terminal device is about to enter a first area, which is an area where the terminal device switches from the first network device to a second network device, or an area where the first network device and the second network device jointly transmit; before the terminal device enters the first area, the first network device sends first indication information to the terminal device, the first indication information being used to instruct the measurement of a first tracking reference signal of the second network device.

[0007] In the above technical solution, the first network device determines that the terminal device is about to perform cell handover or joint transmission. Before the terminal device performs cell handover or joint transmission, the first network device sends a first indication message to the terminal device to trigger the terminal device to start measuring the first tracking reference signal before performing cell handover or joint transmission. This means that in the initial stage after completing cell handover or in the initial stage of joint transmission, the terminal device can directly demodulate the downlink signal from the second network device based on the measurement result of the first tracking reference signal. The terminal device does not need to wait for the MAC-CE signaling of the second network device, thereby reducing the time overhead of the terminal device in obtaining measurement results. This avoids the problem that in the initial stage after completing cell handover or in the initial stage of joint transmission, the terminal device receives the downlink signal from the second network device but has not yet received the MAC-CE signaling of the second network device (or has not yet completed the measurement of the first tracking reference signal), and cannot compensate for the time offset and frequency offset in time based on the result of the first tracking reference signal, resulting in a decrease in the demodulation performance of the downlink signal, thus improving communication quality.

[0008] In one possible design, the first network device determines that the terminal device is about to enter the first area, including: the first network device receiving information on the first reference signal reception quality from the terminal device; when the difference between the first reference signal reception quality and the reference signal reception quality of the terminal device in one or more neighboring cells is less than or equal to a first threshold, the first network device determines that the terminal device is about to enter the first area.

[0009] In the above design, the first network device can compare the reference signal reception quality of the terminal device in the current cell with the reference signal reception quality of the terminal device in one or more neighboring cells to determine whether the terminal device is about to enter the first area. For example, if the difference between the reference signal reception quality of the current cell and the reference signal reception quality of the terminal device in one or more neighboring cells is less than or equal to a first threshold, the first network device can determine that the terminal device is about to enter the first area. Alternatively, if the reference signal reception quality of the current cell is less than or equal to the reference signal reception quality of the terminal device in one or more neighboring cells, the first network device can determine that the terminal device is about to enter the first area.

[0010] In one possible design, the first network device determines that the terminal device is about to enter the first area, including: the first network device determines that the terminal device is about to enter the first area based on the direction of movement of the terminal device and the network topology information in which the first network device is located.

[0011] In the above design, the first network device can determine whether the terminal device is about to enter the first area based on the moving direction of the terminal device and the network topology information of the first network device. Since the network topology information of the first network device may include, but is not limited to, the identifiers of at least one neighboring cell, the identifiers of at least one network device adjacent to the first network device, the location information of at least one network device adjacent to the first network device (such as longitude and / or latitude information), or the positional relationship between the at least one network device and the first network device (such as being due north or due south of the first network device), or the relative position of the at least one network device (such as its position relative to the first network device), the first network device, by combining the moving direction of the terminal device and the network topology information, can accurately determine the next network device the terminal device will access, or the distance between the terminal device and the next network device it will access, thereby enabling the first network device to accurately determine whether the terminal device is about to enter the first area.

[0012] In one possible design, the method further includes: a first network device receiving first information from a terminal device, the first information indicating a first quantity and a second quantity, wherein the first quantity is the number of simultaneously active transmission configuration indication states supported by the terminal device, the second quantity is the number of simultaneously measured tracking reference signals supported by the terminal device, and the transmission configuration indication states are used to indicate the correspondence between tracking reference signals and services; when the first quantity is greater than or equal to 2 and the second quantity is greater than or equal to 2, the first network device determines that the terminal device has the ability to compensate for time offset and frequency offset based on the measurement results of the first tracking reference signal and the measurement results of the second tracking reference signal, wherein the second tracking reference signal is the tracking reference signal of the first network device.

[0013] In the above design, the first network device can determine whether the terminal device has the capability to compensate for time and frequency offsets based on the measurement results of the first and second tracking reference signals by using the first information reported by the terminal device. For example, if it is determined that the terminal device has the capability to compensate for time and frequency offsets based on the measurement results of the first and second tracking reference signals, the first network device can send a first indication message to the terminal device before the terminal device enters the first area. Since the terminal device has the capability to compensate for time and frequency offsets based on the measurement results of the first and second tracking reference signals, after receiving the first indication message, the terminal device can measure the first tracking reference signal to obtain the measurement result, and after the terminal device enters the first area, it can compensate for time and frequency offsets based on the measurement results of the first tracking reference signal, thereby improving the communication quality between the terminal device and the second network device in the initial stage after cell handover (or the initial stage of joint transmission).

[0014] In one possible design, the method further includes: a first network device receiving third indication information from a terminal device, the third indication information being used to indicate that the terminal device has the ability to compensate for time offset and frequency offset based on the measurement results of a first tracking reference signal and a second tracking reference signal, wherein the second tracking reference signal is the tracking reference signal of the first network device.

[0015] In the above design, the terminal device can directly instruct the first network device that it has the capability to compensate for time and frequency offsets based on the measurement results of the first and second tracking reference signals. Thus, before the terminal device enters the first area, the first network device can send a first indication message to the terminal device. Since the terminal device has the capability to compensate for time and frequency offsets based on the measurement results of the first and second tracking reference signals, after receiving the first indication message, the terminal device can measure the first tracking reference signal to obtain the measurement result. After entering the first area, the terminal device can compensate for the time and frequency offsets based on the measurement results of the first tracking reference signal, thereby improving the communication quality between the terminal device and the second network device in the initial phase after cell handover (or the initial phase of joint transmission).

[0016] In one possible design, compensating for time and frequency offsets based on the measurement results of the first and second tracking reference signals includes increasing the filtering coefficients of the crystal oscillator for time and frequency offsets based on the first tracking reference signal.

[0017] In the above design, the terminal device can increase the filtering coefficient of the crystal oscillator for time offset and frequency offset. In this way, when the terminal device receives DCI signaling from the second network device, it can immediately compensate for the time offset and frequency offset based on the measurement results of the first tracking reference signal. This allows the terminal device to compensate for the time offset and frequency offset in a timely manner, avoiding the problem of reduced demodulation performance due to the inability to compensate for the time offset and frequency offset in a timely manner.

[0018] In one possible design, the first indication information includes at least one of an identifier of the first tracking reference signal or information about the time-frequency resources carrying the first tracking reference signal.

[0019] In the above design, the first indication information sent by the first network device to the terminal device may include at least one of the identifier of the first tracking reference signal or the information of the time-frequency resources carrying the first tracking reference signal. In this way, the terminal device can complete the reception of the first tracking reference signal of the second network device according to the identifier of the first tracking reference signal (or the time-frequency resources carrying the first tracking reference signal), so that the terminal device can start measuring the first tracking reference signal before entering the first area.

[0020] In one possible design, before the terminal device enters the first area, the method further includes: the first network device receiving a first message from the second network device, the first message including first indication information.

[0021] In the above design, before the terminal device enters the first area, the second network device can send a first message to the first network device. Correspondingly, the first network device receives the first message, thereby enabling it to determine the identifier of the second network device's first tracking reference signal and / or the time-frequency resources carrying the first tracking reference signal. Furthermore, when the first network device determines that the terminal device is about to enter the first area, it can send the identifier of the first tracking reference signal and / or the time-frequency resources carrying the first tracking reference signal to the terminal device, enabling the terminal device to complete the reception of the first tracking reference signal.

[0022] In one possible design, before receiving the first message from the second network device, the method further includes: the first network device sending a second message to the second network device, the second message being used to request the first indication information.

[0023] In the above design, before the terminal device enters the first area, the first network device can send a second message to the second network device. Accordingly, the second network device receives the second message so that after receiving the second message, the second network device sends the identifier of the first tracking reference signal and / or the information of the time-frequency resources carrying the first tracking reference signal to the first network device.

[0024] Secondly, embodiments of this application provide a communication method, which can be executed by a terminal device or by a component of the terminal device (such as a processor, chip, or chip system). In this method: before the terminal device enters a first area, the terminal device receives first indication information from a first network device, the first indication information indicating that a first tracking reference signal of a second network device is measured. The first area is the area where the terminal device switches from the first network device to the second network device, or the first area is the area where the first network device and the second network device jointly transmit. The terminal device measures the first tracking reference signal to obtain a first measurement result. After the terminal device enters the first area, the terminal device receives a first downlink signal from the second network device. The terminal device demodulates the first downlink signal based on the first measurement result.

[0025] In one possible design, after the terminal device enters the first area, the method further includes: the terminal device receiving second indication information from a second network device, the second indication information being used to indicate demodulation of the first downlink signal based on the first measurement result.

[0026] In one possible design, the method further includes: the terminal device sending information about the first reference signal reception quality to the first network device, the information about the first reference signal reception quality being used to determine that the terminal device is about to enter a first area.

[0027] In one possible design, the method further includes: a terminal device sending first information to a first network device, the first information indicating a first quantity and a second quantity, the first information being used to determine that the terminal device has the ability to compensate for time offset and frequency offset based on the measurement results of a first measurement result and a second tracking reference signal, wherein the first quantity is the number of simultaneously active transmission configuration indication states supported by the terminal device, the second quantity is the number of simultaneously measured tracking reference signals supported by the terminal device, the transmission configuration indication states are used to indicate the correspondence between tracking reference signals and services, and the second tracking reference signal is the tracking reference signal of the first network device.

[0028] In one possible design, the method further includes: the terminal device sending third indication information to the first network device, the third indication information being used to indicate that the terminal device has the ability to compensate for time offset and frequency offset based on the measurement results of the first measurement result and the second tracking reference signal, the second tracking reference signal being the tracking reference signal of the first network device.

[0029] In one possible design, compensating for time and frequency offsets based on the first measurement result and the measurement result of the second tracking reference signal includes increasing the filtering coefficient of the crystal oscillator for time and frequency offsets based on the first measurement result.

[0030] Thirdly, embodiments of this application provide a communication method, which can be executed by a second network device or by a component of the second network device (such as a processor, chip, or chip system). In this method: before a terminal device enters a first area, the second network device sends a first message to a first network device. The first message includes first indication information, which includes at least one of an identifier of a first tracking reference signal or information about time-frequency resources carrying the first tracking reference signal. The first area is the area where the terminal device switches from the first network device to the second network device, or the first area is the area where the first network device and the second network device jointly transmit. The first indication information is used by the terminal device to measure the first tracking reference signal to obtain a first measurement result. After the terminal device enters the first area, the second network device sends second indication information and a first downlink signal to the terminal device. The second indication information is used to instruct the demodulation of the first downlink signal based on the first measurement result.

[0031] In one possible design, before the second network device sends a first message to the first network device, the method further includes: the second network device receiving a second message from the first network device, the second message being used to request first indication information.

[0032] Fourthly, embodiments of this application provide a communication device, which may be a first network device or a device within the first network device. The communication device may include a processing module and a transceiver module, which can perform the corresponding functions performed by the first network device in any of the design examples of the first aspect described above. Wherein:

[0033] The processing module is used to determine that the terminal device is about to enter the first area, which is the area where the terminal device switches from the first network device to the second network device, or the first area is the area where the first network device and the second network device jointly transmit.

[0034] The transceiver module is used to send first indication information to the terminal device before the terminal device enters the first area. The first indication information is used to instruct the measurement of the first tracking reference signal of the second network device.

[0035] In one possible design, the transceiver module is specifically used to: receive information on the reception quality of a first reference signal from the terminal device; and the processing module is specifically used to: determine that the terminal device is about to enter the first area when the difference between the reception quality of the first reference signal and the reception quality of the reference signal of the terminal device in one or more neighboring cells is less than or equal to a first threshold.

[0036] In one possible design, the processing module is specifically used to: determine, based on the direction of movement of the terminal device and the network topology information of the first network device, that the terminal device is about to enter the first area.

[0037] In one possible design, the transceiver module is further configured to: receive first information from the terminal device, the first information indicating a first quantity and a second quantity, wherein the first quantity is the number of transmission configuration indication states that the terminal device supports being activated simultaneously, and the second quantity is the number of tracking reference signals that the terminal device supports being measured simultaneously, the transmission configuration indication states being used to indicate the correspondence between the tracking reference signals and the service; the processing module is further configured to: when the first quantity is greater than or equal to 2 and the second quantity is greater than or equal to 2, determine that the terminal device has the ability to compensate for time offset and frequency offset based on the measurement results of the first tracking reference signal and the measurement results of the second tracking reference signal, wherein the second tracking reference signal is the tracking reference signal of the first network device.

[0038] In one possible design, the transceiver module is further configured to: receive third indication information from the terminal device, the third indication information being used to indicate that the terminal device has the ability to compensate for time offset and frequency offset based on the measurement results of the first tracking reference signal and the measurement results of the second tracking reference signal, the second tracking reference signal being the tracking reference signal of the first network device.

[0039] In one possible design, compensating for time and frequency offsets based on the measurement results of the first and second tracking reference signals includes increasing the filtering coefficients of the crystal oscillator for time and frequency offsets based on the first tracking reference signal.

[0040] In one possible design, the first indication information includes at least one of an identifier of the first tracking reference signal or information about the time-frequency resources carrying the first tracking reference signal.

[0041] In one possible design, before the terminal device enters the first area, the transceiver module is further configured to: receive a first message from a second network device, the first message including first indication information.

[0042] In one possible design, before receiving the first message from the second network device, the transceiver module is further configured to: send a second message to the second network device, the second message being used to request the first indication information.

[0043] Fifthly, embodiments of this application provide a communication device, which may be a terminal device or a device within a terminal device. The communication device may include a processing module and a transceiver module, which can perform the corresponding functions performed by the terminal device in any of the design examples of the second aspect described above. Wherein:

[0044] The transceiver module is used to receive first indication information from the first network device before the terminal device enters the first area. The first indication information is used to indicate the measurement of the first tracking reference signal of the second network device. The first area is the area where the terminal device switches from the first network device to the second network device, or the first area is the area where the first network device and the second network device jointly transmit.

[0045] The processing module is used to measure the first tracking reference signal and obtain the first measurement result;

[0046] The transceiver module is also used to receive the first downlink signal from the second network device after the terminal device enters the first area;

[0047] The processing module is also used to demodulate the first downlink signal based on the first measurement result.

[0048] In one possible design, after the terminal device enters the first area, the transceiver module is further configured to: receive second indication information from the second network device, the second indication information being used to indicate demodulation of the first downlink signal based on the first measurement result.

[0049] In one possible design, the transceiver module is further configured to: send information on the reception quality of a first reference signal to a first network device, the information on the reception quality of the first reference signal being used to determine that the terminal device is about to enter a first area.

[0050] In one possible design, the transceiver module is further configured to: send first information to a first network device, the first information indicating a first quantity and a second quantity, the first information being used to determine that the terminal device has the capability to compensate for time offset and frequency offset based on the measurement results of the first measurement result and the second tracking reference signal, wherein the first quantity is the number of simultaneously active transmission configuration indication states supported by the terminal device, the second quantity is the number of simultaneously measured tracking reference signals supported by the terminal device, the transmission configuration indication states being used to indicate the correspondence between the tracking reference signals and services, and the second tracking reference signal being the tracking reference signal of the first network device.

[0051] In one possible design, the transceiver module is further configured to: send third indication information to the first network device, the third indication information being used to instruct the terminal device to have the ability to compensate for time offset and frequency offset based on the measurement results of the first measurement result and the second tracking reference signal, the second tracking reference signal being the tracking reference signal of the first network device.

[0052] In one possible design, compensating for time and frequency offsets based on the first measurement result and the measurement result of the second tracking reference signal includes increasing the filtering coefficient of the crystal oscillator for time and frequency offsets based on the first measurement result.

[0053] Sixthly, embodiments of this application provide a communication device, which may be a second network device or a device within a second network device. The communication device may include a processing module and a transceiver module, which can perform the corresponding functions performed by the second network device in any of the design examples of the third aspect described above. Wherein:

[0054] The transceiver module is used to send a first message to a first network device before the terminal device enters the first area. The first message includes first indication information. The first indication information includes at least one of an identifier of a first tracking reference signal or information on time-frequency resources carrying the first tracking reference signal. The first area is the area where the terminal device switches from the first network device to the second network device, or the first area is the area where the first network device and the second network device jointly transmit. The first indication information is used by the terminal device to measure the first tracking reference signal to obtain a first measurement result.

[0055] In addition, it is used to send a second indication information and a first downlink signal to the terminal device, wherein the second indication information is used to indicate demodulation of the first downlink signal based on the first measurement result.

[0056] In one possible design, before the second network device sends the first message to the first network device, the transceiver module is further configured to:

[0057] Receive a second message from the first network device, the second message being used to request the first instruction information.

[0058] In a seventh aspect, embodiments of this application provide a communication device, which includes a processor for implementing the method executed by the first network device in the first aspect described above. The communication device may further include a memory for storing program instructions and data. The memory is coupled to the processor, which can call and execute the program instructions stored in the memory to implement any of the methods executed by the first network device in the first aspect described above. The communication device may further include a transceiver for communicating with other devices. Exemplarily, the other devices are terminal devices or second network devices.

[0059] Eighthly, embodiments of this application provide a communication device, which includes a processor for implementing the method executed by the terminal device in the third aspect described above. The communication device may further include a memory for storing program instructions and data. The memory is coupled to the processor, which can call and execute the program instructions stored in the memory to implement any of the methods executed by the terminal device in the third aspect described above. The communication device may also include a transceiver for communicating with other devices. Exemplarily, the other device is a first network device or a second network device.

[0060] Ninthly, embodiments of this application provide a communication device, which includes a processor for implementing the method executed by the second network device in the third aspect described above. The communication device may further include a memory for storing program instructions and data. The memory is coupled to the processor, which can call and execute the program instructions stored in the memory to implement any of the methods executed by the second network device in the third aspect described above. The communication device may further include a transceiver for communicating with other devices. Exemplarily, the other devices are terminal devices or first network devices.

[0061] In a tenth aspect, this application also provides a computer-readable storage medium storing a computer program or instructions. When the computer program or instructions are executed, they can implement the method executed by the first network device in any of the design examples of the first aspect, or the method executed by the second network device in any of the design examples of the third aspect.

[0062] Eleventhly, this application also provides a computer-readable storage medium storing a computer program or instructions, which, when executed, can implement the method executed by the terminal device in any of the design examples of the second aspect described above.

[0063] In a twelfth aspect, this application also provides a computer program product, including instructions that, when run on a computer, cause the computer to perform the method executed by the first network device in any of the design examples of the first aspect, or the method executed by the second network device in any of the design examples of the third aspect.

[0064] In a thirteenth aspect, this application also provides a computer program product, including instructions that, when run on a computer, cause the computer to perform the method executed by the terminal device in any of the design examples of the second aspect described above.

[0065] In a fourteenth aspect, embodiments of this application provide a chip system including a processor and potentially a memory, for implementing the method executed by a first network device in any of the design examples of the first aspect, or the method executed by a second network device in any of the design examples of the third aspect. The chip system may be composed of chips or may include chips and other discrete devices.

[0066] In a fifteenth aspect, embodiments of this application provide a chip system including a processor and potentially a memory, for implementing the method executed by the terminal device in any of the design examples of the second aspect described above. The chip system may be composed of chips or may include chips and other discrete devices.

[0067] In a sixteenth aspect, this application also provides a communication system, which includes the communication device in any of the design examples of the fourth aspect above, and / or the communication device in any of the design examples of the fifth aspect above, and / or the communication device in any of the design examples of the sixth aspect above.

[0068] The beneficial effects of the second to sixteenth aspects and their implementation methods can be referred to the description of the beneficial effects of the first aspect and its implementation methods. Attached Figure Description

[0069] Figure 1 This is a schematic diagram illustrating a joint transmission between a first network device and a second network device in an embodiment of this application.

[0070] Figure 2 This is a schematic diagram of a cell handover area in an embodiment of this application;

[0071] Figure 3 This is a schematic diagram of a communication system applicable to the embodiments of this application;

[0072] Figure 4 A flowchart illustrating a communication method provided in an embodiment of this application;

[0073] Figure 5 A flowchart illustrating another communication method provided in an embodiment of this application;

[0074] Figure 6 A flowchart illustrating another communication method provided in an embodiment of this application;

[0075] Figure 7 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0076] Figure 8 This is a schematic diagram of another communication device provided in an embodiment of this application;

[0077] Figure 9 This is a schematic diagram of another communication device provided in an embodiment of this application;

[0078] Figure 10 This is a schematic diagram of another communication device provided in an embodiment of this application;

[0079] Figure 11 A schematic block diagram of a communication device provided in the embodiments of this application;

[0080] Figure 12 Another schematic block diagram of the communication device provided in the embodiments of this application;

[0081] Figure 13 Another schematic block diagram of the communication device provided in the embodiments of this application;

[0082] Figure 14 Another schematic block diagram of the communication device provided in the embodiments of this application. Detailed Implementation

[0083] To facilitate understanding, the specific concepts and terms involved in the embodiments of this application will be explained below.

[0084] (1) Network equipment can be access network equipment, also known as radio access network (RAN) equipment, which is a device that provides wireless communication functions for terminal equipment. Access network equipment includes, but is not limited to, fifth-generation (5G) wireless communication devices. thIn 5G, next-generation base stations (gNB), evolved node B (eNB), remote radio units (RRU), baseband units (BBU), transmitting and receiving points (TRP), transmitting points (TP), base stations in future mobile communication systems, or access points in WiFi systems can be included. Access network equipment can also be radio controllers, central units (CU), and / or distributed units (DU) in cloud radio access network (CRAN) scenarios, or network equipment can be relay stations, vehicle-mounted equipment, and network equipment in future evolved networks.

[0085] In this application embodiment, the device for implementing the function of the network device can be a network device itself; it can also be a device capable of supporting the network device in implementing the function, such as a chip system, which can be installed in the network device. In this application embodiment, taking a network device as an example, the technical solution provided by the embodiments of this application is described.

[0086] (2) A terminal device, also known as a user equipment, is a device with wireless transceiver capabilities. Terminal devices can be deployed on land (e.g., in vehicles, high-speed trains, or bullet trains); on water (e.g., on ships); or in the air (e.g., on airplanes, drones, balloons, and satellites). The terminal device can be a mobile phone, tablet computer, computer with wireless transceiver capabilities, virtual reality terminal device, augmented reality terminal device, wireless terminal device in industrial control, wireless terminal device in autonomous driving, wireless terminal device in telemedicine, wireless terminal device in smart grids, wireless terminal device in transportation safety, wireless terminal device in smart cities, or wireless terminal device in smart homes. This application does not limit this specific application.

[0087] The terminal device can communicate with multiple access network devices using different technologies. For example, the terminal device can communicate with access network devices supporting long term evolution (LTE), access network devices supporting 5G, or simultaneously with both LTE-enabled and 5G-enabled access network devices. This application does not limit the scope of the embodiments described herein.

[0088] In this application embodiment, the device for implementing the terminal's functions can be a terminal device; it can also be a device capable of supporting the terminal device in implementing the functions, such as a chip system, which can be installed in the terminal device. In this application embodiment, the chip system can be composed of chips, or it can include chips and other discrete devices. In this application embodiment, taking the terminal device as an example to illustrate the technical solutions provided by the embodiments of this application, we will describe the technical solutions provided by the embodiments of this application.

[0089] (3) A merged cell, also known as a logical cell, can deploy multiple network devices (such as RRUs) within a merged cell. Each of these network devices corresponds to a physical cell, and multiple physical cells can constitute a merged cell. For example, when a terminal device accesses a merged cell, the master network device among the multiple network devices can configure the time-frequency resources carrying the tracking reference signals of each network device to the terminal device through radio resource control (RRC) signaling. This can save the time overhead of the network devices configuring the time-frequency resources carrying the tracking reference signals for the terminal device after it accesses the physical cell.

[0090] (4) Joint transmission can refer to at least two network devices jointly sending downlink signals and TRS to a terminal device. For example, ... Figure 1 As shown, the terminal device moves from the area covered by the first network device to the area covered by the second network device. The first and second network devices share a common coverage area. When the terminal device is within this common coverage area, the first and second network devices can jointly send downlink signals and a Transmission Signal Receipt (TRS) to the terminal device. Specifically, when the channel quality is poor, the first and second network devices send the same downlink signal to the terminal device to increase the received power of the downlink signal and improve communication quality; when the channel quality is good, the first and second network devices send different downlink signals to the terminal device to improve transmission efficiency. The area of ​​joint transmission can be the common coverage area of ​​the at least two network devices, or a subset of the common coverage area of ​​the at least two network devices (e.g., ...). Figure 1 (As shown).

[0091] (5) The first area may refer to the area where the first network device and the second network device jointly transmit, or the area where the terminal device switches from the first network device to the second network device.

[0092] The area jointly transmitted by the first network device and the second network device can be the common coverage area of ​​the first network device and the second network device, or it can be a subset of the common coverage area of ​​the first network device and the second network device (e.g., Figure 1 (As shown).

[0093] The area where a terminal device switches from a first network device to a second network device can also be called the area where the terminal device performs the handover. For example, such as Figure 2 As shown, during the process of a terminal device moving from the coverage area of ​​a first network device to the coverage area of ​​a second network device, the terminal device needs to perform a handover, that is, switch from the first network device to the second network device. The handover from the first network device to the second network device may include one or more of the following stages: a handover preparation stage, a handover execution stage, and a handover completion stage. For example, the handover preparation stage may refer to the period between the first network device sending a handover request to the second network device and the first network device sending a handover command to the terminal device. The handover execution stage may refer to the period between the terminal device receiving the handover command and the terminal device establishing a connection with the second network device. The handover completion stage may refer to the period when the terminal device establishes a connection with the second network device and begins data transmission with the second network device.

[0094] The area where a terminal device switches from the first network device to the second network device can be understood as the area where the terminal device is located during the switch from the first network device to the second network device.

[0095] It should be noted that if the terminal device switches from the first network device to the second network device at the handover point, it means that the time required for the terminal device to perform cell handover is very short and the cell handover area is very small. Therefore, the first area can be an area that includes all possible handover points.

[0096] (6) Transmission Configuration Indicator-State (TCI-State) can be used to indicate the correspondence between tracking reference signals and services. For example, TCI-State can be used to indicate the quasico-location (QCL) relationship between tracking reference signals and services. The service can refer to physical downlink control channel (PDCCH) data and / or physical downlink shared channel (PDSCH) data. For example, when a network device broadcasts a tracking reference signal, a terminal device may receive multiple tracking reference signals. In this case, the terminal device can determine the tracking reference signal used for demodulating the PDCCH (and / or PDSCH) from these multiple tracking reference signals based on the TCI-State field of the DCI to obtain PDCCH data (and / or PDSCH data). For example, the terminal device receives multiple tracking reference signals and multiple PDSCH data. The multiple tracking reference signals may include tracking reference signal 1 and tracking reference signal 2, and the multiple PDSCH data may include PDSCH data 1 and PDSCH data 2. If the TCI-State indicates that the tracking reference signal 1 and PDSCH data 1 are in a QCL relationship, and the tracking reference signal 2 and PDSCH data 2 are in a QCL relationship, then based on this TCI-State, the terminal device can obtain PDSCH data 1 according to the tracking reference signal 1 and obtain PDSCH data 2 according to the tracking reference signal 2.

[0097] Alternatively, the TCI-State can be used to indicate the QCL relationship between the tracking reference signal and the demodulation reference signal (DMRS). For example, a network device broadcasts a tracking reference signal, and a terminal device may receive multiple tracking reference signals. In this case, the terminal device can determine the tracking reference signal used for the DMRS from among the multiple tracking reference signals based on the TCI-State field of the DCI, in order to obtain the PDCCH data (and / or PDSCH data) corresponding to that DMRS.

[0098] (7) The Transmission Configuration Indicator State (TCI-PresentinDCI) carried in the downlink control information is a field in the air interface signaling that can be used to determine whether the DCI includes the TCI-State. For example, if the network device configures TCI-Present in DCI to be "enabled", then TCI-PresentinDCI is used to indicate that the DCI includes the TCI-State field. If the network device configures TCI-Present in DCI to be "inaccessible", then TCI-PresentinDCI is used to indicate that the DCI does not include the TCI-State field.

[0099] (8) A tracking reference signal is used to track the time and frequency offsets during communication between the network device and the terminal device, in order to compensate for the time offset caused by air interface transmission delay and the frequency offset caused by the Doppler effect. For example, the tracking reference signal can be TRS or SSB, etc., and this application embodiment is not limited to this. The following description uses TRS as the tracking reference signal as an example. It can be understood that the technical solutions applicable to TRS in the embodiments of this application are also applicable to SSB.

[0100] (9) In the embodiments of this application, "multiple" refers to two or more. Therefore, in the embodiments of this application, "multiple" can also be understood as "at least two". "At least one" can be understood as one or more, such as one, two or more. For example, including at least one means including one, two or more, and it does not limit which ones are included. For example, including at least one of A, B and C, then it can include A, B, C, A and B, A and C, B and C, or A and B and C. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / ", unless otherwise specified, generally indicates that the related objects before and after are in an "or" relationship.

[0101] Unless otherwise stated, the ordinal numbers such as "first," "second," and "third" mentioned in the embodiments of this application are used to distinguish multiple objects and are not used to limit the order, sequence, priority, or importance of multiple objects.

[0102] The technical solutions in this application can be applied to various communication systems, such as LTE systems, 5G mobile communication systems, new radio (NR) systems, and other future evolutionary communication systems. This application does not limit these applications.

[0103] This application will present various aspects, embodiments, or features relating to a system that may include multiple devices, components, modules, etc. It should be understood and appreciated that individual systems may include additional devices, components, modules, etc., and / or may not include all the devices, components, modules, etc. discussed in conjunction with the accompanying drawings. Furthermore, combinations of these approaches may also be used.

[0104] Furthermore, in the embodiments of this application, the term "exemplary" is used to indicate that it is an example, illustration, or description. Any embodiment or design scheme described as "exemplary" in the embodiments of this application should not be construed as being better or more advantageous than other embodiments or design schemes. Specifically, the use of the term "exemplary" is intended to present the concept in a concrete manner.

[0105] The network architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0106] In this application, some scenarios are illustrated using NR networks as examples. It should be noted that the solutions in this application can also be applied to other wireless communication networks, and the corresponding names can be replaced by the names of the corresponding functions in other wireless communication networks.

[0107] To facilitate understanding of the embodiments of this application, the communication system to which the embodiments of this application are applicable is described below.

[0108] Figure 3 A schematic diagram of a communication system applicable to an embodiment of this application is shown. For example... Figure 3 As shown, the communication system 100 may include network device 101, network device 102, and terminal device 103. Terminal device 103 is located along... Figure 3During the movement along the thick line shown, the serving cell of terminal device 103 changes from the first cell to the second cell. The first cell can be referred to as the source cell of terminal device 103, and the second cell can be referred to as the target cell of terminal device 103. Correspondingly, network device 101 belonging to the first cell can be referred to as the source network device of terminal device 103, and network device 102 belonging to the second cell can be referred to as the target network device of terminal device 103. Network device 101 can be configured with multiple antennas, network device 102 can be configured with multiple antennas, and terminal device 106 can also be configured with multiple antennas. Before terminal device 103 switches from the first cell to the second cell, network device 101 can communicate with terminal device 103. After terminal device 103 switches from the first cell to the second cell, network device 102 can communicate with terminal device 103. Additionally, network device 101 or network device 102 can also communicate with other terminal devices besides terminal device 103, which will not be elaborated further here.

[0109] For example, the coverage area of ​​the first cell may partially overlap with the coverage area of ​​the second cell (e.g.) Figure 3 As shown in the diagram, network device 101 and network device 102 share a common coverage area. It is understood that the coverage area of ​​the first cell may not overlap with the coverage area of ​​the second cell; this embodiment does not limit this. Network device 101 and network device 102 may belong to the same merged cell or different merged cells; this embodiment does not limit this.

[0110] It should be noted that, Figure 3 The simplified illustration is for illustrative purposes only. This communication system may also include other network devices or other terminal devices, and the embodiments of this application are not limited thereto.

[0111] The following describes some of the technical features involved in the embodiments of this application.

[0112] As mentioned earlier, terminal devices can compensate for time offsets caused by air interface transmission delays and frequency offsets caused by the Doppler effect by measuring TRS, thereby ensuring timing synchronization with network devices and matching their own frequency with the downlink signal frequency, thus improving communication quality. The following section will use... Figure 3Taking the communication system shown as an example, the process of the terminal device compensating for time and frequency offsets by measuring TRS is described through scenarios 1 and 2 respectively. Scenario 1 is the initial stage after the terminal device completes cell handover, and scenario 2 is the initial stage of joint transmission between network device 101 and network device 102. The following explanation uses scenario 1 as the initial stage after the terminal device completes cell handover, where the first cell and the second cell belong to different merged cells, and scenario 2 as the initial stage of joint transmission between network device 101 and network device 102, where the first cell and the second cell belong to the same merged cell.

[0113] Scenario 1, during the initial stage of terminal device 103 handover from the first cell to the second cell, the process by which terminal device 103 compensates for time offset and frequency offset by measuring TRS is as follows:

[0114] In step A1, after terminal device 103 accesses the second cell, network device 102 configures the time-frequency resources carrying TRS for terminal device 103 via RRC signaling. Correspondingly, terminal device 103 receives information about the time-frequency resources carrying TRS.

[0115] In step A2, network device 102 broadcasts the TRS and sends MAC-CE signaling to terminal device 103. Correspondingly, terminal device 103 can receive the MAC-CE signaling and receive the TRS according to the time-frequency resources carrying the TRS. The MAC-CE signaling can be used to instruct the measurement of the TRS.

[0116] In step A3, the terminal device 103 can measure the TRS according to the MAC-CE signaling to obtain the measurement result. The measurement result may include at least one of the time offset estimate or the frequency offset estimate.

[0117] In step A4, network device 102 sends DCI signaling and downlink signals to terminal device 103. Correspondingly, terminal device 103 receives the DCI signaling and downlink signals. The DCI signaling can be used to instruct the adjustment of the downlink signal based on measurement results. The downlink signal can be PDCCH, PDSCH, or a combination of both, etc., and this application does not limit this to any particular type.

[0118] In step A5, the terminal device 103 adjusts the downlink signal based on the measurement results.

[0119] In the initial stage after the terminal device 103 completes cell handover, it needs to receive information from the network device 102 regarding the time-frequency resources configured to carry the TRS, as well as the MAC-CE signaling from the network device 102, before it can begin measuring the TRS. This means that the terminal device 103 needs to wait a relatively long time before it can begin measuring the TRS. During this waiting period, if the terminal device 103 receives a downlink signal from the network device 102, it will not wait for the TRS measurement to be completed before demodulating the downlink signal, but will directly demodulate the downlink signal. Since the terminal device 103 has not yet measured the TRS (or has not yet completed the TRS measurement), it cannot compensate for the time offset caused by the air interface transmission delay or compensate for the frequency offset caused by the Doppler effect, thereby reducing the demodulation performance of the downlink signal and reducing communication quality.

[0120] It should be noted that the execution order of steps A1 to A5 described above is not limited in this embodiment. For example, terminal device 103 may receive TRS from network device 102 before accessing the second cell. As another example, network device 102 may simultaneously send TRS and MAC-CE signaling to terminal device 103, or it may broadcast TRS first and then send MAC-CE signaling to terminal device 103.

[0121] In scenario 2, during the initial stage of joint transmission by terminal device 103, the process by which terminal device 103 compensates for time offset and frequency offset by measuring TRS is as follows:

[0122] In step B1, network device 102 broadcasts the TRS and sends MAC-CE signaling to terminal device 103. Correspondingly, terminal device 103 receives the TRS and MAC-CE signaling. The MAC-CE signaling can be used to instruct the TRS to be measured.

[0123] In step B2, the terminal device 103 can determine the time and frequency resources carrying the TRS based on the resource pool of the merged cell, and measure the TRS based on the determined time and frequency resources to obtain the measurement results.

[0124] In step B3, network device 102 sends DCI signaling and downlink signals to terminal device 103. Correspondingly, terminal device 103 receives the DCI signaling and downlink signals. The DCI signaling can be used to instruct the adjustment of the downlink signal based on measurement results. The downlink signal can be PDCCH, PDSCH, or a combination of both, etc., and this application does not limit this to any particular type.

[0125] Step B4: Terminal device 103 demodulates the downlink signal based on the measurement results.

[0126] In Scenario 2, since network devices 101 and 102 belong to the same merged cell, when a terminal device accesses this merged cell, the primary network device in the merged cell (such as network device 102, or other network devices within the merged cell) can configure the time-frequency resources carrying the TRS for each network device to the terminal device via RRC signaling. This means that network device 102 does not need to configure the time-frequency resources carrying the TRS for the terminal device. Although Scenario 2 saves the time overhead of network device 102 configuring the time-frequency resources carrying the TRS for the terminal device 103, when the terminal device 103 enters the joint transmission area, it needs to receive MAC-CE signaling from network device 102 and determine the time-frequency resources carrying the TRS from the resource pool of the merged cell before it can start measuring the TRS. This means that the terminal device 103 still needs to wait a relatively long time before it can start measuring the TRS. Similarly, during this waiting period, if terminal device 103 receives a downlink signal from network device 102, terminal device 103 will not wait for the TRS measurement to be completed before demodulating the downlink signal, but will directly demodulate the downlink signal. Since terminal device 103 has not yet measured the TRS (or has not yet completed the TRS measurement), terminal device 103 cannot compensate for the time offset caused by air interface transmission delay and the frequency offset caused by the Doppler effect, thereby reducing the demodulation performance of the downlink signal and reducing communication quality.

[0127] It should be noted that the execution order of steps B1 to B4 described above is not limited in this embodiment. For example, terminal device 103 may receive a TRS from network device 102 before entering the area of ​​joint transmission. As another example, network device 102 may send both TRS and MAC-CE signaling to terminal device 103 simultaneously, or it may broadcast TRS first and then send MAC-CE signaling to terminal device 103.

[0128] As can be seen from the above descriptions of scenarios 1 and 2, in the initial stage after the terminal device completes cell handover and in the initial stage of joint transmission, the terminal device needs to wait for a long time before it can start measuring TRS. That is, the terminal device cannot compensate for the time offset caused by air interface transmission delay and the frequency offset caused by the Doppler effect in a timely manner based on the results of TRS measurement. This leads to a reduction in the demodulation performance of downlink signals during the waiting period, thereby reducing communication quality.

[0129] Therefore, this application provides a communication method to reduce the delay in TRS measurement by a terminal device during the initial stage after cell handover or during the initial stage of joint transmission, thereby improving communication quality. In this method, a first network device can send first indication information to the terminal device before the terminal device enters a first area. The first area can be the area where the terminal device hands over from the first network device to a second network device, or the area where the first and second network devices are jointly transmitting. Therefore, the terminal device can measure the first TRS before cell handover (or before joint transmission). Then, after cell handover (or joint transmission), the downlink signal can be directly demodulated based on the measurement result. In this way, the time overhead of the terminal device measuring TRS during the initial stage after cell handover (or the initial stage of joint transmission) can be saved. That is, during the initial stage after cell handover (or the initial stage of joint transmission), the terminal device can track time offset and frequency offset in a timely manner, thereby avoiding the problem of demodulation performance degradation caused by the terminal device's failure to compensate for time offset and frequency offset in a timely manner, and improving communication quality.

[0130] Figure 4 This is a flowchart illustrating a communication method provided in an embodiment of this application. This method can be applied to... Figure 3 In the communication system 100 shown, wherein Figure 4 The dashed lines in the diagram represent optional steps. The terminal device in this embodiment can be... Figure 3 The terminal device 103 shown can be a first network device. Figure 3 The network device 101 shown can be a second network device. Figure 3 The network device 102 shown. It is understood that, in this embodiment, the steps performed by the network device can also be specifically performed by a module or component of the network device, such as a chip or chip system within the network device; similarly, the steps performed by the terminal device can also be specifically performed by a module or component of the terminal device, such as a chip or chip system within the terminal device. Figure 4 As shown, the method may include:

[0131] S401: The second network device broadcasts the first TRS. Correspondingly, the terminal device receives the first TRS.

[0132] For example, the second network device may broadcast the first TRS periodically or aperiodically. Accordingly, the terminal device may receive the first TRS from the second network device before entering the first area.

[0133] As an example, the first area could be the area where a terminal device switches from a first network device to a second network device. This area, where the device switches from the first network device to the second network device, can also be referred to as the area where the terminal device performs cell handover. For example, the cell handover performed by the terminal device may include a handover preparation phase, a handover execution phase, and a handover completion phase, such as... Figure 2 As shown. For example, the area where the terminal device performs cell handover can be a shared coverage area of ​​the first network device and the second network device, or a subset of the shared coverage area of ​​the first network device and the second network device, etc., and this application embodiment is not limited in this respect. In this case, the first network device can be the source device for cell handover of the terminal device, and the second network device can be the target device for cell handover of the terminal device.

[0134] As another example, the first area can also be an area jointly transmitted by the first network device and the second network device. For instance, the area jointly transmitted by the first network device and the second network device can be a shared coverage area of ​​the first network device and the second network device. As yet another example, the area jointly transmitted by the first network device and the second network device can also be a subset of the shared coverage area of ​​the first network device and the second network device, such as... Figure 1 As shown.

[0135] When the first area is a region jointly transmitted by the first network device and the second network device, the terminal device will perform cell handover during its movement from the first area to the second terminal device. The area where the terminal device performs cell handover can be a subset of the region jointly transmitted by the first and second network devices, such as... Figure 1 As shown.

[0136] In other words, a terminal device may switch from a first network device to a second network device within a certain area of ​​the first area. In this scenario, during the period from when the terminal device enters the first area until the cell handover begins, the first network device can act as the primary network device in the joint transmission between the first and second network devices. During the period from when the terminal device completes the cell handover and leaves the first area, the second network device can act as the primary network device in the joint transmission between the first and second network devices.

[0137] In joint transmission, the primary network device can adjust the joint transmission method based on channel quality (e.g., sending the same downlink signal to the terminal device or sending a different downlink signal). Taking the first network device as the primary network device in joint transmission as an example, when poor channel quality is detected, the first network device can instruct the second network device to send the same downlink signal as the first network device to the terminal device, thereby increasing the received power of the downlink signal and improving communication quality. Conversely, when good channel quality is detected, the first network device can instruct the second network device to send a different downlink signal to the terminal device, thereby improving transmission efficiency.

[0138] It is understood that the technical solutions applicable to cell handover in the embodiments of this application are also applicable to cell handover in the domain of the joint transmission area.

[0139] S402: The first network device determines that the terminal device is about to enter the first area.

[0140] For example, the first network device may determine whether a terminal device is about to enter a first area based on the reference signal received power (RSRP), the direction of movement of the terminal device, and the network topology information of the first network device. The network topology information of the first network device may include, but is not limited to, the identifiers of at least one neighboring cell, the identifiers of at least one network device adjacent to the first network device, the location information (such as longitude and / or latitude information) of the at least one network device adjacent to the first network device, or the location relationship between the at least one network device and the first network device (such as being due north of the first network device, or due south of the first network device), or the relative position of the at least one network device (such as its position relative to the first network device).

[0141] As an example, the first network device can determine whether a terminal device is about to enter a first area based on the RSRP. For instance, the terminal device can periodically report a first RSRP to the first network device. The first network device receives the first RSRP, which can be the RSRP of a sounding reference signal (SRS). The first network device determines whether the terminal device is about to enter the first area based on the first RSRP.

[0142] For example, a first network device may compare a first RSRP with the RSRP of a terminal device in one or more neighboring cells to determine whether the terminal device is about to enter a first area. If the difference between the first RSRP and the RSRP of the terminal device in one or more neighboring cells for multiple consecutive periods is less than or equal to a first threshold, the first network device may determine that the terminal device is about to enter the first area. Alternatively, if the first RSRP for multiple consecutive periods is less than or equal to the RSRP of the terminal device in one or more neighboring cells, the first network device may determine that the terminal device is about to enter the first area.

[0143] For example, the first network device can compare the first RSRP with the RSRP of the terminal device in its strongest neighboring cell to determine whether the terminal device is about to enter the first area. If the difference between the first RSRP and the RSRP of the terminal device in its strongest neighboring cell is less than or equal to a first threshold for multiple consecutive cycles, the first network device can determine that the terminal device is about to enter the first area. Here, the strongest neighboring cell can be the cell with the best detected RSRP, excluding the cell covered by the first network device (i.e., the first cell).

[0144] As another example, the first network device can determine whether the terminal device is about to enter the first area based on the terminal device's movement method and the network topology information where the first network device is located. For example, the first network device can obtain the identifier of the second cell (or the identifier of the second network device) that the terminal device will switch to according to the movement direction based on its network topology information and movement direction, determine the distance between the second network device and the current terminal device based on the identifier of the second cell (or the identifier of the second network device), and when the distance between the second network device and the current terminal device is less than or equal to a second threshold, the first network device determines that the terminal device is about to enter the first area.

[0145] S403: The first network device sends a first instruction message to the terminal device. Correspondingly, the terminal device receives the first instruction message.

[0146] For example, the first indication information may be MAC-CE signaling, which can be used to instruct the terminal device to measure the first TRS. As another example, the first indication information may include second information, which may include at least one of the following: the identifier of the first TRS, information about the time-frequency resources carrying the first TRS, or the TCI-State number corresponding to the first TRS. Wherein, if the first area is the area where the terminal device performs cell handover, the first TRS may be a TRS transmitted by the second network device. Alternatively, if the first area is an area jointly transmitted by the first network device and the second network device, the first TRS may be a TRS jointly transmitted by the first network device and the second network device.

[0147] S404: The terminal device measures the first TRS according to the first instruction information and obtains the first measurement result.

[0148] For example, the terminal device measures the first TRS and obtains a first measurement result, which may include an estimated time offset and / or a estimated frequency offset of the first downlink signal arriving at the terminal device.

[0149] S405: The terminal device has entered the first area.

[0150] For example, if the first area is the area where the terminal device performs cell handover, then the terminal device enters the first area and performs cell handover. If the first area is the area where the first network device and the second network device jointly transmit, then the terminal device enters the first area and jointly transmits with the first network device and the second network device.

[0151] Optionally, after the terminal device enters the first area, the second network device may send a second instruction message and a first downlink signal to the terminal device, instructing the terminal device to demodulate the first downlink signal according to the first measurement result, i.e., execute the steps S406 to S408. Alternatively, after the terminal device enters the first area, the second network device may not send the second instruction message to the terminal device, i.e., the terminal device can directly use the first measurement result to demodulate the first downlink signal by default, i.e., execute the steps S407 and S408.

[0152] S406: The second network device sends a second instruction message to the terminal device. Correspondingly, the terminal device receives the second instruction message.

[0153] The second indication information can be DCI signaling, which can be used to instruct the demodulation of the first downlink signal based on the first measurement result. For example, after determining that the terminal device has entered the first area, the second network device can send the second indication information to the terminal device, and the terminal device receives the second indication information. For example, if the first area is an area where the terminal device is performing cell handover, the second network device can send the second indication information to the terminal device after the terminal device completes cell handover (e.g., the second network device can determine that the terminal device has completed cell handover based on the terminal device's cell handover completion instruction, i.e., after the second network device and the terminal device establish an RRC connection). Alternatively, if the first area is an area where the first network device and the second network device jointly transmit, the second network device can send the second indication information to the terminal device after the terminal device enters the area where the first network device and the second network device jointly transmit (e.g., the second network device can determine that the terminal device has entered the first area based on the first network device's joint transmission instruction, at which point the terminal device has not yet performed cell handover).

[0154] S407: The second network device sends a first downlink signal to the terminal device. Correspondingly, the terminal device receives the first downlink signal.

[0155] The first downlink signal can be a PDCCH, a PDSCH, or both; this embodiment is not limited in this respect. For example, after determining that the terminal device has entered the first area, the second network device can send the first downlink signal to the terminal device, and the terminal device can receive the first downlink signal. For example, if the first area is an area where the terminal device performs cell handover, the second network device can send the first downlink signal to the terminal device after the terminal device completes cell handover (e.g., the second network device can determine that the terminal device has completed cell handover based on the terminal device's cell handover completion instruction). Alternatively, if the first area is an area where the first network device and the second network device jointly transmit, the second network device can send the first downlink signal to the terminal device after the terminal device enters the first area (e.g., the second network device can determine that the terminal device has entered the first area based on the first network device's joint transmission instruction).

[0156] S408: The terminal device adjusts the first downlink signal based on the first measurement result.

[0157] For example, after receiving the first downlink signal, the terminal device can immediately adjust its crystal oscillator according to the time offset estimate and frequency offset estimate in the first measurement result to compensate for the time offset caused by the air interface transmission delay of the first downlink signal and to compensate for the frequency offset caused by the Doppler effect, so as to make the terminal device and the second network device synchronized in positioning and the terminal device and the terminal device's receiving frequency consistent with the frequency of the first downlink signal.

[0158] For example, a terminal device can adjust its crystal oscillator in the following way: When the next crystal oscillator adjustment time arrives, instead of filtering its own crystal oscillator's frequency offset record using historical values, it directly writes the estimated time offset and frequency offset values ​​from the first measurement result. These historical values ​​can be the measurement result of the second TRS, which is the TRS broadcast by the first network device. Using this method, since the crystal oscillator adjustment is not a one-step process, when the terminal device completes the initial stage after accessing the second cell, its own crystal oscillator may not yet have completed filtering based on the measurement result of the second TRS. Therefore, when the terminal device receives the second indication information, it can directly perform filtering based on the first measurement result, reducing the time overhead of the terminal device compensating for time and frequency offsets and improving reliability.

[0159] It should be noted that, Figure 4The execution order of steps S401 to S408 in this embodiment is merely an example, and the present application does not limit this. For example, the second network device may broadcast the first TRS before or after step S402, as long as the terminal device receives the first TRS before entering the first area. As another example, the first network device may execute steps S406 and S407 separately, execute steps S406 and S407 simultaneously, or execute only step S407 without executing step S406.

[0160] The following examples, 1 and 2, illustrate... Figure 4 The communication method shown is described in detail.

[0161] Example 1

[0162] Figure 5 This application provides a communication method according to its embodiments. This method can be executed by a terminal device and a network device, or it can be executed by a chip in the terminal device and a chip in the network device. Figure 5 The first network device in the process can be the one mentioned above. Figure 3 The network device 101 in the middle, the second network device can be the one mentioned above. Figure 3 The network device 102 and the terminal device can be the aforementioned Figure 3 Terminal device 103 in the example. In Example 1, the first area is the area where the terminal device performs cell handover. The terminal device can complete the measurement of the first TRS before performing cell handover, so that the terminal device can demodulate the first downlink signal of the second network device in a timely manner based on the measurement result of the first TRS, such as... Figure 5 The methods shown may include:

[0163] S501: The terminal device sends first information to the first network device. Correspondingly, the first network device receives the first information.

[0164] For example, the first information may include a first quantity and a second quantity. The first quantity may be the number of TCI-States that the terminal device supports activating simultaneously, and the second quantity may be the number of TRSs that the terminal device supports measuring simultaneously. TCI-States can be used to indicate the correspondence between TRSs and services, such as the quasi-co-address relationship between TRSs and services. The service may be PDCCH data and / or PDSCH data.

[0165] For example, when establishing a connection with a first network device (such as initial access, cell handover access, or RRC connection recovery), the terminal device may report to the first network device the number of simultaneously active TCI-States and the number of simultaneously measured TRSs that it supports. This allows the first network device to determine whether the terminal device possesses a first capability based on the information reported by the terminal device. The first capability may be the ability to compensate for time and frequency offsets based on the measurement results of the first and second TRSs, or it may be the ability to simultaneously measure at least two TRSs (such as the first and second TRSs) and compensate for time and frequency offsets based on the measurement results of the first and second TRSs. The second TRS is the TRS of the first network device.

[0166] The ability of the terminal device to compensate for time and frequency offsets based on the measurement results of the first TRS and the second TRS can be understood as: the terminal device supports seamless (or rapid) switching from adjusting the crystal oscillator based on the measurement results of the second TRS to adjusting the crystal oscillator based on the measurement results of the first TRS.

[0167] For example, compensating for time and frequency offsets based on the measurements of the first and second TRSs may include increasing the crystal oscillator's filtering coefficients for time and frequency offsets based on the measurement results of the first TRS, or setting the crystal oscillator's filtering coefficients for time and frequency offsets to 1. For instance, the terminal device may increase the crystal oscillator's filtering coefficients for time and frequency offsets (or set the crystal oscillator's filtering coefficients for time and frequency offsets to 1) by following these steps:

[0168] Step C1: The terminal device receives the first downlink signal (or the second indication information and the first downlink signal) from the second network device. For details, please refer to [link / reference]. Figure 3 Step S407 (or steps S406 and S407) in the process.

[0169] Step C2: After receiving the first downlink signal (or the second indication information and the first downlink signal), the terminal device immediately determines whether a first measurement result exists. If a first measurement result exists, the steps shown in step C3 are executed; if no first measurement result exists or a partial first measurement result exists (e.g., the terminal device has not yet completed the measurement of the first tracking reference signal), the process ends (i.e., the filtering coefficients of the crystal oscillator for time offset and frequency offset are not increased or the filtering coefficients of the crystal oscillator for time offset and frequency offset are not set to 1).

[0170] Step C3: The terminal device determines the stability of the first measurement result. If the stability of the first measurement result is greater than or equal to the fifth threshold, then the steps shown in step C4 are executed; if the stability of the first measurement result is less than the fifth threshold, the process ends (i.e., the filtering coefficients of the crystal oscillator for time and frequency offsets are not increased or the filtering coefficients of the crystal oscillator for time and frequency offsets are not set to 1). For example, the terminal device can determine the stability of the first measurement result based on channel quality or channel correlation.

[0171] Step C4: The terminal device increases the filtering coefficient of the crystal oscillator for time and frequency offset based on the first measurement result (or sets the filtering coefficient of the crystal oscillator for time and frequency offset to 1).

[0172] By following steps C1 to C4, the terminal device can increase the filtering coefficients of the crystal oscillator for time and frequency offsets (or set the filtering coefficients of the crystal oscillator for time and frequency offsets to 1). Since the filtering coefficients of the crystal oscillator for time and frequency offsets are increased (or the filtering coefficients of the crystal oscillator for time and frequency offsets are set to 1), the filtering time of the crystal oscillator for time and frequency offsets is shortened. This means that the time delay between the terminal device receiving the first downlink signal and demodulating the first downlink signal according to the first measurement result can be reduced. This allows the terminal device to quickly adjust the crystal oscillator according to the first measurement result to quickly compensate for time and frequency offsets, thereby improving the demodulation performance of the first downlink signal and improving communication quality.

[0173] S502: The first network device determines whether the terminal device has the first capability based on the first information.

[0174] For example, if the first quantity is greater than or equal to 2 and the second quantity is greater than or equal to 2, the first network device can determine that the terminal device has the first capability, that is, execute the contents shown in steps S503 to S514. Alternatively, if the first quantity is less than 2 or the second quantity is less than 2, the first network device can determine that the terminal device does not have the first capability, that is, the process ends.

[0175] The terminal device can report first information to the first network device. The first network device determines whether the terminal device possesses the first capability based on the first information, i.e., the content shown in steps S501 and S502 above. In one possible implementation, the terminal device can also directly determine whether it possesses the first capability based on third indication information. The third indication information can be used to indicate whether the terminal device possesses the first capability. For example, the terminal device can send third indication information to the first network device, and the first network device receives the third indication information. After receiving the third indication information, the first network device can directly determine whether the terminal device possesses the first capability based on the third indication information, without needing to determine whether the terminal device possesses the first capability based on the first quantity and the second quantity.

[0176] S503: The first network device sends the sixth instruction information to the terminal device.

[0177] For example, the sixth indication information can be used to indicate that the DCI includes TCI-State. For example, after determining that the terminal device has the first capability, the first network device can send air interface signaling to the terminal device, which includes the first field (i.e., the sixth indication information). The first network device can configure the first field to "enable" to indicate that the DCI includes TCI-State, so that after the terminal device receives the DCI, it can determine the correspondence between the first TRS and the service based on the TCI-State included in the DCI. The first field can be the TCI-present in DCI field.

[0178] S504: The second network device broadcasts the first TRS. Correspondingly, the terminal device receives the first TRS.

[0179] For example, the second network device can broadcast the first TRS periodically or aperiodically. The specific implementation process of step S504 can be found in [reference needed]. Figure 4 The content shown in step 401 will not be repeated here.

[0180] S505: The first network device determines the direction of movement of the terminal device.

[0181] For example, the first network device can determine the direction of movement of the terminal device based on a first frequency offset from the terminal device. The first frequency offset can be obtained by the terminal device measuring a second TRS, wherein the second TRS is the TRS broadcast by the first network device.

[0182] S506: The first network device determines that the terminal device is about to enter the first area based on the direction of movement of the terminal device and the network topology information where the first network device is located.

[0183] In this example, the first area is the area where the terminal device performs cell handover. The first network device determines that the terminal device is about to enter the first area, which means that the terminal device will perform cell handover.

[0184] For example, the first network device can determine whether the terminal device needs to perform a cell handover based on its network topology information and direction of movement. Specifically, the first network device can obtain the identifier of the second cell that the terminal device needs to switch to according to its network topology information and direction of movement, determine the distance between the second network device and the current terminal device based on the identifier of the second cell, and determine that the terminal device needs to perform a cell handover when the distance between the second network device and the current terminal device is less than or equal to a second threshold.

[0185] The first network device can determine whether the terminal device is about to perform a cell handover based on the direction of movement of the terminal device and the network topology information where the first network device is located, that is, execute the steps S505 and S506. In one possible implementation, the first network device can also determine whether the terminal device is about to perform a cell handover based on the first RSRP reported by the terminal device.

[0186] For example, a first network device may compare a first RSRP with the RSRP of a terminal device in one or more neighboring cells to determine whether the terminal device is about to perform a cell handover. If the difference between the first RSRP and the RSRP of the terminal device in one or more neighboring cells is less than or equal to a first threshold for multiple consecutive cycles, the first network device may determine that the terminal device is about to perform a cell handover. Alternatively, if the first RSRP is less than or equal to the RSRP of the terminal device in one or more neighboring cells for multiple consecutive cycles, the first network device may determine that the terminal device is about to perform a cell handover.

[0187] For example, the first network device can compare the first RSRP with the RSRP of the terminal device in its strongest neighboring cell to determine whether the terminal device is about to perform a cell handover. If the difference between the first RSRP and the RSRP of the terminal device in its strongest neighboring cell is less than or equal to a first threshold for multiple consecutive cycles, the first network device can determine that the terminal device is about to perform a cell handover. Here, the strongest neighboring cell can be the cell with the best detected RSRP other than the cell covered by the first network device (i.e., the first cell).

[0188] The first threshold can be greater than the third threshold. The third threshold can be the threshold at which the first network device determines that the terminal device needs to perform cell handover. For example, when the difference between the first RSRP and the RSRP of the terminal device in one or more neighboring cells (or the strongest neighboring cell) for multiple consecutive cycles is less than or equal to the third threshold, the first network device determines that the terminal device needs to perform cell handover. For example, the third threshold is -2 dB. Because a value that is too small will cause the first network device to fail to send the first indication information to the terminal device before the terminal device performs cell handover, the terminal device will still need to receive the first indication information or measure the first TRS in the initial stage after completing the cell handover, thereby reducing the demodulation performance of the first downlink signal and reducing communication quality. Therefore, the above method can ensure that the terminal device completes the measurement of the first TRS before performing cell handover, enabling the terminal device to demodulate the first downlink signal in a timely manner based on the measurement result of the first TRS in the initial stage after completing the cell handover, thereby improving the demodulation performance of the first downlink signal and improving communication quality.

[0189] Optionally, if the first network device and the second network device belong to the same merged cell, the first network device can determine the second information through the resource pool of the merged cell, i.e., steps S507 and S508 are not executed. Alternatively, if the first network device and the second network device belong to different merged cells, the first network device can execute steps S507 and S508 to obtain the second information. Alternatively, if the first network device and the second network device belong to different merged cells, the second network device can report the second information to the first network device, i.e., only step S508 is executed.

[0190] S507: The first network device sends a second message to the second network device. Correspondingly, the second network device receives the second message.

[0191] For example, the second message can be used to request second information, which may include at least one of the following: the identifier of the first TRS, information about the time-frequency resources carrying the first TRS, or the number of the TCI-State corresponding to the first TRS.

[0192] S508: The second network device sends a first message to the first network device. Correspondingly, the first network device receives the first message.

[0193] The first message may include the second message.

[0194] S509: The first network device sends a first instruction message to the terminal device. Correspondingly, the terminal device receives the first instruction message.

[0195] For example, the first indication information can be used to instruct the terminal device to measure the first TRS. For example, the first indication information can be MAC-CE signaling. This first indication information includes second information (or the first indication information includes at least one of the following: the identifier of the first TRS, information about the time-frequency resources carrying the first TRS, or the TCI-State number corresponding to the first TRS). For example, the first network device can send MAC-CE signaling to the terminal device, which includes a second field. The first network device can configure this second field as the identifier of the first TRS or the TCI-State number corresponding to the first TRS, etc., to instruct the measurement of the first TRS. The second field can be a TCI-State field.

[0196] S510: The terminal device measures the received first TRS according to the first instruction information and obtains the first measurement result.

[0197] For example, a second network device broadcasts a TRS (Transmission Scheduler). A terminal device receives multiple TRSs. The terminal device can determine the time-frequency resources carrying the first TRS based on second information, identify the first TRS from the multiple TRSs based on the time-frequency resources carrying the first TRS, and measure the first TRS to obtain a first measurement result. For example, the first measurement result may include an estimated time offset and / or an estimated frequency offset when the downlink signal corresponding to the first TRS arrives at the terminal device. The specific implementation method of the terminal device measuring the TRS in this embodiment is not limited.

[0198] S511: The terminal device performs cell handover, switching from the first network device to the second network device.

[0199] The specific implementation method of cell handover for terminal devices in this application embodiment is not limited.

[0200] Optionally, during the initial stage of cell handover completion by the terminal device, the second network device may send a second indication message and a first downlink signal to the terminal device, instructing the terminal device to demodulate the first downlink signal based on the first measurement result, i.e., execute the steps S512 to S514. Alternatively, during the initial stage of cell handover completion by the terminal device, the second network device may not send the second indication message to the terminal device, i.e., the terminal device can directly use the first measurement result to demodulate the first downlink signal by default, i.e., execute the steps S513 and S514.

[0201] S512: The second network device sends a second instruction message to the terminal device. Correspondingly, the terminal device receives the second instruction message.

[0202] The second indication information can be DCI signaling, which can be used to indicate the demodulation of the first downlink signal based on the first measurement result. For example, the second indication information can be DCI signaling. The second network device can send DCI signaling to the terminal device, which includes a second field. The second network device can configure the second field as an identifier of the first TRS or the number of the TCI-State corresponding to the first TRS, etc., to indicate the demodulation of the first downlink signal based on the first measurement result. The second field can include TCI-State, etc.

[0203] S513: The second network device sends a first downlink signal to the terminal device. Correspondingly, the terminal device receives the first downlink signal.

[0204] The first downlink signal can be PDCCH, PDSCH, or a combination of PDCCH and PDSCH; this application does not limit this.

[0205] S514: The terminal device demodulates the first downlink signal based on the first measurement result.

[0206] The specific implementation processes of steps S512 to S514 above can be referred to respectively. Figure 4 The results obtained in steps S406 to S408 are not described in detail here.

[0207] In one possible implementation, before step S511, i.e. before the terminal device performs cell handover, the first network device broadcasts a second TRS, and the terminal device receives the second TRS; the first network device may send a fourth indication information to the terminal device, and the terminal device receives the fourth indication information, which can be used to indicate that the second TRS is measured; the terminal device measures the second TRS according to the fourth indication information and obtains a second measurement result; the first network device may send a fifth indication information and a second downlink signal to the terminal device, and the terminal device receives the fifth indication information and the second downlink signal, which can be used to indicate that the second downlink signal is demodulated according to the second measurement result; the terminal device demodulates the second downlink signal according to the second measurement result. In this manner, before the terminal device performs cell handover, it can simultaneously measure the first TRS and the second TRS. This reduces the time overhead of the terminal device performing TRS measurement in the initial stage after cell handover, improves the demodulation performance of the first downlink signal, and enhances the communication quality between the second network device and the terminal device. At the same time, it also ensures the demodulation performance of the second downlink signal and the communication quality between the first network device and the terminal device, thereby improving the communication reliability between the terminal device and the network device before and after cell handover.

[0208] The fourth indication information can be MAC-CE signaling, which may include third information. The third information may include at least one of the following: the identifier of the second TRS, information about the time-frequency resources carrying the second TRS, or the TCI-State number corresponding to the second TRS. For example, the first network device may send MAC-CE signaling to the terminal device, which includes a second field. The first network device may configure this second field as the identifier of the second TRS or the TCI-State number corresponding to the second TRS, to indicate that the second TRS is being measured. The fifth indication information can be DCI signaling, which may include the third information. For example, the first network device may send DCI signaling to the terminal device, which includes a second field. The first network device may configure this second field as the identifier of the second TRS or the TCI-State number corresponding to the second TRS, to indicate that the second downlink signal is demodulated based on the second measurement result. The second field may be a TCI-State field. The second downlink signal may be a PDCCH, a PDSCH, or both; this embodiment does not limit this.

[0209] It should be noted that, Figure 5 The execution order of steps S501 to S514 in this embodiment is merely an example, and the present application does not limit this. For example, the second network device may broadcast the first TRS before step S504 or after step S505, as long as the terminal device receives the first TRS before cell handover. As another example, the first network device may send the first indication information to the terminal device after step S508 or before step S507.

[0210] In the above embodiments of this application, before determining that the terminal device is about to perform a cell handover, the first network device sends a first indication message to the terminal device to instruct the terminal device to measure the first TRS from the second network device. In the initial stage after the terminal device completes the cell handover, the second network device sends a first downlink signal (or a second indication message and a first downlink signal) to the terminal device, enabling the terminal device to demodulate the first downlink signal based on the measurement result of the first TRS. Since the terminal device has already completed the measurement of the first TRS before the cell handover, it is not necessary to measure the first TRS again in the initial stage after the cell handover. The downlink signal can be directly demodulated based on the measurement result, thereby saving the time overhead of the terminal device acquiring the measurement result in the initial stage after the cell handover. This avoids the problem of demodulation performance degradation caused by the terminal device's failure to compensate for time and frequency offsets in a timely manner, thereby improving the communication quality between the second network device and the terminal device.

[0211] Example 2

[0212] Figure 6 This is a flowchart illustrating another communication method provided in an embodiment of this application, wherein, Figure 6 The dashed lines in the text represent optional steps. In Example 2, the first area is the area where the first network device and the second network device jointly transmit. The terminal device can complete the measurement of the first TRS before entering the first area, so that the terminal device can demodulate the first downlink signal of the second network device in a timely manner based on the measurement result of the first TRS. Among them, steps S601 to S604, S608, S609, and S611 to S613 are respectively connected with... Figure 5 Steps S501 to S504, S509, S510, and S512 to S514 are the same, except that:

[0213] S605: The terminal device sends a first RSRP to the first network device. Correspondingly, the first network device receives the first RSRP.

[0214] For example, a terminal device can periodically report a first RSRP to a first network device. The first network device receives the first RSRP, which can be the RSRP of an SRS. The first network device can determine, based on the first RSRP, that the terminal device has entered the common coverage area of ​​the first network device and the second network device and is about to enter the area for joint transmission.

[0215] S606: The first network device determines, based on the first RSRP, that the terminal device has entered the common coverage area of ​​the first network device and the second network device, and is about to enter the area for joint transmission.

[0216] For example, a first network device can compare a first RSRP with the RSRP of a terminal device in one or more neighboring cells to determine whether the terminal device has entered the shared coverage area of ​​the first and second network devices and is about to enter the area for joint transmission. If the difference between the first RSRP and the RSRP of the terminal device in the one or more neighboring cells for multiple consecutive periods is less than or equal to a first threshold, the first network device can determine that the terminal device has entered the shared coverage area of ​​the first and second network devices and is about to enter the area for joint transmission. Alternatively, if the first RSRP for multiple consecutive periods is less than or equal to the RSRP of the terminal device in the one or more neighboring cells, the first network device can determine that the terminal device has entered the shared coverage area of ​​the first and second network devices and is about to enter the area for joint transmission.

[0217] For example, the first network device can compare the first RSRP with the RSRP of the terminal device in its strongest neighbor cell to determine whether the terminal device has entered the shared coverage area of ​​the first and second network devices and is about to enter the area for joint transmission. If the difference between the first RSRP and the RSRP of the terminal device in its strongest neighbor cell for multiple consecutive cycles is less than or equal to a first threshold, the first network device can determine that the terminal device has entered the shared coverage area of ​​the first and second network devices and is about to enter the area for joint transmission. The strongest neighbor cell can be the cell with the best detected RSRP other than the cell covered by the first network device (i.e., the first cell).

[0218] The first threshold can be greater than the third threshold and also greater than the fourth threshold. The third threshold can be used by the first network device to determine when the terminal device needs to perform a cell handover. For example, when the difference between the first RSRP and the RSRP of the terminal device in one or more neighboring cells (or the strongest neighboring cell) for multiple consecutive cycles is less than or equal to the third threshold, the first network device determines that the terminal device needs to perform a cell handover. The fourth threshold can be used by the first network device to determine when to perform joint transmission. For example, when the difference between the first RSRP and the RSRP of the terminal device in one or more neighboring cells (or the strongest neighboring cell) for multiple consecutive cycles is less than or equal to the fourth threshold, the first network device determines that joint transmission should be performed. For example, the fourth threshold could be 6 dB. Since joint transmission occurs after the terminal device enters the shared coverage area of ​​the first and second network devices and before the terminal device performs a cell handover, a too-small first threshold might cause the first network device to fail to send the first indication information to the terminal device before the terminal device enters the joint transmission area. This would require the terminal device to receive the first indication information or measure the first TRS during the initial stage of joint transmission, thereby reducing the demodulation performance of the first downlink signal and lowering communication quality. Therefore, by adopting the above method, it can be ensured that the terminal device completes the measurement of the first TRS before joint transmission, so that the terminal device can demodulate the first downlink signal in a timely manner according to the measurement result of the first TRS in the initial stage of joint transmission, thereby improving the demodulation performance of the first downlink signal and improving the communication quality.

[0219] S607: The first network device obtains the second information.

[0220] For example, the second information may include at least one of the following: the identifier of the first TRS, information about the time-frequency resources carrying the first TRS, or the TCI-State number corresponding to the first TRS. Since the first area is a joint transmission area for the first network device and the second network device, the resource pool of the joint transmission stores relevant information of each network device in the joint transmission (such as the identifier of each network device, the identifier of each network device's TRS, the time-frequency resource information carrying each network device's TRS, or the TCI-State number corresponding to each network device's TRS, etc.). Therefore, the first network device can directly obtain the second information from the resource pool of the joint transmission, which can reduce the overhead of air interface resources and improve the utilization rate of air interface resources.

[0221] S610: The terminal device enters the first area.

[0222] For example, in Example 2, the first area is the area where the first network device and the second network device jointly transmit data, such as... Figure 1 As shown. The terminal device enters the first area, which is the area where the first network device and the second network device jointly transmit data, and then performs joint transmission.

[0223] In one possible implementation, before step S609, i.e., before the terminal device enters the area of ​​joint transmission, the first network device can broadcast a second TRS, and the terminal device receives the second TRS; the first network device can send a fourth indication message to the terminal device, and the terminal device receives the fourth indication message, which can be used to indicate that the second TRS should be measured; the terminal device measures the second TRS according to the fourth indication message and obtains a second measurement result; the first network device can send a fifth indication message and a second downlink signal to the terminal device, and the terminal device receives the fifth indication message and the second downlink signal, which can be used to indicate that the second downlink signal should be demodulated according to the second measurement result; the terminal device demodulates the second downlink signal according to the second measurement result. In this way, before the terminal device enters the area of ​​joint transmission, it can simultaneously complete the measurement of the first TRS and the second TRS. This reduces the time overhead of the terminal device completing the TRS measurement in the initial stage of joint transmission, improves the demodulation performance of the first downlink signal, and improves the communication quality of joint transmission, while also ensuring the demodulation performance of the second downlink signal and the communication quality between the first network device and the terminal device, thereby improving communication reliability.

[0224] It should be noted that, Figure 6The execution order of steps S601 to S612 in the above example is merely one example, and the embodiments of this application are not limited thereto. For example, the second network device may broadcast the first TRS before step S604, or it may broadcast the first TRS after step S604 and before step S609. As another example, the second network device may also broadcast the first TRS while the terminal device is executing step S604.

[0225] In the above embodiments of this application, before determining that the terminal device is about to perform joint transmission, the first network device sends a first indication message to the terminal device to instruct the terminal device to measure the first TRS from the second network device. In the initial stage of the joint transmission, the second network device sends a first downlink signal (or a second indication message and a first downlink signal) to the terminal device, enabling the terminal device to demodulate the first downlink signal based on the measurement result of the first TRS. Since the terminal device has already completed the measurement of the first TRS before joint transmission, it is not necessary to measure the first TRS again in the initial stage of joint transmission. The first downlink signal can be directly demodulated based on the first measurement result, thereby saving the time overhead of the terminal device acquiring the first measurement result in the initial stage of joint transmission. This avoids the problem of degraded demodulation performance of the first downlink signal due to the terminal device's failure to compensate for time and frequency offsets in a timely manner, thus improving communication quality.

[0226] In the embodiments provided above, the methods provided by this application have been described from the perspectives of a first network device, a terminal device, a second network device, and the interaction between the three. To implement the functions of the methods provided in the embodiments of this application, the first network device, the terminal device, and the second network device may include hardware structures and / or software modules, implementing the above functions in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Whether a particular function is executed in the form of hardware structures, software modules, or a combination of hardware structures and software modules depends on the specific application and design constraints of the technical solution.

[0227] Figure 7 A schematic diagram of a communication device 700 is shown. The communication device 700 can be one of the aforementioned... Figures 4-6The first network device (or second network device) in any of the illustrated embodiments can implement the functions of the first network device (or second network device) in the method provided in this application embodiment; the communication device 700 can also be a device capable of supporting the first network device (or second network device) to implement the functions of the first network device (or second network device) in the method provided in this application embodiment. The communication device 700 can be a hardware structure, a software module, or a hardware structure plus a software module. The communication device 700 can be implemented by a chip system. In the embodiments of this application, the chip system can be composed of chips, or it can include chips and other discrete devices.

[0228] The communication device 700 may include a processing module 701 and a transceiver module 702.

[0229] As an example, when the communication device 700 is as described above Figures 4-6 When the first network device is used in any of the embodiments shown, the processing module 701 can be used to perform, for example... Figure 4 Step S402 in the illustrated embodiment, or performing as follows Figure 5 Steps S502, 505, or S506 in the illustrated embodiments, or performing steps such as... Figure 6 Steps S602, S606, or S607 in the illustrated embodiments may be used to instruct the transceiver module 702 to complete the transceiver function, and / or other processes used to support the technology described herein.

[0230] The transceiver module 702 can be used to perform tasks such as Figure 4 Step S403 in the illustrated embodiment, or performing as shown Figure 5 Steps S501, S503, S507 to S509, etc., in the embodiments shown, or performed as follows: Figure 6 Steps S601, S603, S605, or S608 in the illustrated embodiments, and / or other processes used to support the techniques described herein.

[0231] As another example, when the communication device 700 is as described above Figures 4-6 When the second network device is used in any of the embodiments shown, the processing module 701 can be used to perform, for example... Figure 4 Step S405 in the illustrated embodiment, or performing as shown in the example Figure 5 Step S511 in the illustrated embodiment, or performing as follows Figure 6 Step S610 in the illustrated embodiment may be used to instruct the transceiver module 702 to complete the transceiver function, and / or other processes to support the technology described herein.

[0232] The transceiver module 702 can be used to perform, for example Figure 4Steps S401, S405 to S407, etc., in the illustrated embodiments, or performed as follows: Figure 5 Steps S504, S507, S508, S512 to S513, etc., in the embodiments shown, or performed as follows: Figure 6 Steps S604, S611, or S612 in the illustrated embodiments, and / or other processes used to support the techniques described herein.

[0233] The transceiver module 702 is used for communication between the communication device 700 and other modules. It can be a circuit, device, interface, bus, software module, transceiver or any other device that can realize communication.

[0234] All relevant content of each step involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0235] It should be noted that the processing module may also be called a processing unit, processor, processing device, or processing board, etc., and the transceiver module may also be called a communication module, transceiver, transceiver unit, or transceiver circuit, etc., and the embodiments of this application are not limited in this respect.

[0236] The module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in each embodiment of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0237] Figure 8 A schematic diagram of a communication device 800 is shown. The communication device 800 can perform the aforementioned... Figures 4-6 The terminal device in any of the illustrated embodiments can implement the functions of the terminal device in the method provided in the embodiments of this application; the communication device 800 can also be a device that supports the terminal device in implementing the functions of the terminal device in the method provided in the embodiments of this application. The communication device 800 can be a hardware structure, a software module, or a hardware structure plus a software module. The communication device 800 can be implemented by a chip system. In the embodiments of this application, the chip system can be composed of chips, or it can include chips and other discrete devices.

[0238] The communication device 800 may include a processing module 801 and a transceiver module 802.

[0239] As an example, processing module 801 can be used to perform actions such as Figure 4 Step S404 or step S408 in the illustrated embodiments, or performing steps such as... Figure 5 Step S510 or step S514 in the illustrated embodiments, or performing steps such as... Figure 6 Step S609 or step S613 in the illustrated embodiments, or instructing the transceiver module 802 to complete the transceiver function, and / or other processes used to support the technology described herein.

[0240] The transceiver module 802 can be used to perform, for example Figure 4 Steps S401, S403, S406, or S407 in the illustrated embodiments, or the following steps may be performed: Figure 5 Steps S501, S503, S509, S512, or S513 in the illustrated embodiments, or the following steps may be performed: Figure 6 Steps S601, S603, S605, S608, S611, or S612 in the illustrated embodiments may be used to instruct the transceiver module 802 to complete the transceiver function, and / or other processes used to support the technology described herein.

[0241] The transceiver module 802 is used for communication between the communication device 800 and other modules. It can be a circuit, device, interface, bus, software module, transceiver or any other device that can realize communication.

[0242] All relevant content of each step involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0243] It should be noted that the processing module may also be called a processing unit, processor, processing device, or processing board, etc., and the transceiver module may also be called a communication module, transceiver, transceiver unit, or transceiver circuit, etc., and the embodiments of this application are not limited in this respect.

[0244] The module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in each embodiment of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0245] like Figure 9 The diagram shows a communication device 900 provided in an embodiment of this application. The communication device 900 can be... Figures 4-6The first network device (or second network device) in any of the illustrated embodiments can implement the functions of the first network device (or second network device) in the method provided in this application embodiment; the communication device 900 can also be a device capable of supporting the first network device (or second network device) to implement the functions of the first network device (or second network device) in the method provided in this application embodiment. The communication device 900 can be a chip system. In this application embodiment, the chip system can be composed of chips or can include chips and other discrete components.

[0246] In terms of hardware implementation, the transceiver module 702 can be a transceiver, which is integrated into the communication device 900 to form the communication interface 910.

[0247] The communication device 900 includes at least one processor 920 for implementing or supporting the communication device 900 in implementing the functions of the second terminal device in the methods provided in the embodiments of this application. Exemplarily, the processor 920 can determine whether the terminal device is about to enter a first area; see the detailed description in the method examples for more details, which will not be repeated here.

[0248] The communication device 900 may further include at least one memory 930 for storing program instructions and / or data. The memory 930 is coupled to the processor 920. The coupling in this embodiment is an indirect coupling or communication connection between devices, units, or modules, and may be electrical, mechanical, or other forms, for information exchange between devices, units, or modules. The processor 920 may operate in conjunction with the memory 930. The processor 920 may execute program instructions stored in the memory 930. At least one of the at least one memories may be included in the processor.

[0249] The communication device 900 may further include a communication interface 910 for communicating with other devices via a transmission medium, thereby enabling devices in the communication device 900 to communicate with other devices. Exemplarily, the communication device 900 may be a first network device, and the other device may be a second network device or a terminal device; alternatively, the communication device 900 may be a second network device, and the other device may be a first network device or a terminal device. The processor 920 may use the communication interface 910 to send and receive data. Specifically, the communication interface 910 may be a transceiver.

[0250] This application embodiment does not limit the specific connection medium between the communication interface 910, processor 920, and memory 930. This application embodiment... Figure 9 The memory 930, processor 920, and communication interface 910 are connected via a bus 940. Figure 9The connections between other components are shown in bold and are for illustrative purposes only, not as limiting information. The bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, Figure 9 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0251] In the embodiments of this application, the processor 920 may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components, and may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.

[0252] In this embodiment, the memory 930 can be non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), or it can be volatile memory, such as random-access memory (RAM). Memory is any other medium capable of carrying or storing desired program code in the form of instructions or data structures, and accessible by a computer, but is not limited thereto. The memory in this embodiment can also be a circuit or any other device capable of implementing storage functions, used to store program instructions and / or data.

[0253] like Figure 10 The diagram shows a communication device 1000 provided in an embodiment of this application. The communication device 1000 may be... Figures 4-6 The terminal device in any of the illustrated embodiments can implement the functions of the terminal device in the method provided in the embodiments of this application; the communication device 1000 can also be a device that supports the terminal device in implementing the functions of the terminal device in the method provided in the embodiments of this application. The communication device 1000 can be a chip system. In the embodiments of this application, the chip system can be composed of chips, or it can include chips and other discrete devices.

[0254] In terms of hardware implementation, the transceiver module 802 can be a transceiver, which is integrated into the communication device 1000 to form the communication interface 1010.

[0255] The communication device 1000 includes at least one processor 1020, which is used to implement or support the communication device 1000 in implementing the functions of the network device in the methods provided in the embodiments of this application. For example, the processor 1020 can measure a first TRS to obtain a first measurement result, and demodulate a first downlink signal based on the first measurement result. See the detailed description in the method examples for further details, which will not be repeated here.

[0256] The communication device 1000 may further include at least one memory 1030 for storing program instructions and / or data. The memory 1030 is coupled to the processor 1020. The coupling in this embodiment is an indirect coupling or communication connection between devices, units, or modules, and can be electrical, mechanical, or other forms, used for information exchange between devices, units, or modules. The processor 1020 may operate in conjunction with the memory 1030. The processor 1020 may execute program instructions stored in the memory 1030. At least one of the at least one memory may be included in the processor.

[0257] The communication device 1000 may further include a communication interface 1010 for communicating with other devices via a transmission medium, thereby enabling the devices in the device 1000 to communicate with other devices. For example, the other device may be a second terminal device. The processor 1020 may use the communication interface 1010 to send and receive data. Specifically, the communication interface 1010 may be a transceiver.

[0258] This application embodiment does not limit the specific connection medium between the communication interface 1010, processor 1020, and memory 1030. This application embodiment... Figure 10 The memory 1030, processor 1020, and communication interface 1010 are connected via a bus 1040. Figure 10 The connections between other components are shown in bold and are for illustrative purposes only, not as limiting information. The bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, Figure 10 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0259] In the embodiments of this application, the processor 1020 may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, capable of implementing or executing the various methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor, etc. The steps of the methods disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or being executed by a combination of hardware and software modules in the processor.

[0260] In this embodiment, the memory 1030 can be non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), or it can be volatile memory, such as random-access memory (RAM). Memory is any other medium capable of carrying or storing desired program code in the form of instructions or data structures, and accessible by a computer, but is not limited thereto. The memory in this embodiment can also be a circuit or any other device capable of implementing storage functions, used to store program instructions and / or data.

[0261] This application also provides a communication device 1100, which can be a terminal device or a circuit. The communication device 1100 can be used to perform the actions performed by the terminal device in the above method embodiments.

[0262] When the communication device is a terminal device Figure 11 A simplified schematic diagram of a terminal device is shown. This is for ease of understanding and illustration. Figure 11 In this context, the terminal device is taken as a mobile phone. For example... Figure 11 As shown, the terminal device includes a processor, memory, radio frequency (RF) circuitry, antenna, and input / output devices. The processor is primarily used for processing communication protocols and data, controlling the terminal device, executing software programs, and processing software program data. The memory is mainly used to store software programs and data. The RF circuitry is mainly used for converting baseband signals to RF signals and processing RF signals. The antenna is mainly used for transmitting and receiving RF signals in the form of electromagnetic waves. Input / output devices, such as touchscreens, displays, and keyboards, are mainly used to receive user input data and output data to the user. It should be noted that some types of terminal devices may not have input / output devices.

[0263] When data needs to be sent, the processor performs baseband processing on the data to be sent and outputs the baseband signal to the radio frequency (RF) circuit. The RF circuit then processes the baseband signal and transmits it outward as electromagnetic waves through the antenna. When data is sent to the terminal device, the RF circuit receives the RF signal through the antenna, converts it into a baseband signal, and outputs the baseband signal to the processor. The processor then converts the baseband signal back into data and processes it. For ease of explanation, Figure 11Only one memory and processor are shown in the illustration. In actual terminal device products, there may be one or more processors and one or more memories. Memory may also be referred to as storage medium or storage device, etc. Memory may be set up independently of the processor or integrated with the processor; this application does not limit this.

[0264] In this embodiment, the antenna and radio frequency circuit with transceiver functions can be considered as the transceiver unit of the terminal device, and the processor with processing functions can be considered as the processing unit of the terminal device. For example... Figure 11 As shown, the terminal device includes a transceiver unit 1110 and a processing unit 1120. The transceiver unit can also be called a transceiver, transceiver machine, transceiver device, etc. The processing unit can also be called a processor, processing board, processing module, or processing device, etc. Optionally, the device in the transceiver unit 1110 used to implement the receiving function can be considered as a receiving unit, and the device in the transceiver unit 1110 used to implement the transmitting function can be considered as a transmitting unit; that is, the transceiver unit 1110 includes both a receiving unit and a transmitting unit. The transceiver unit can sometimes also be called a transceiver machine, transceiver, or transceiver circuit, etc.

[0265] It should be understood that the transceiver unit 1110 is used to perform the sending and receiving operations on the terminal device side in the above method embodiments, and the processing unit 1120 is used to perform other operations on the terminal device in the above method embodiments besides the sending and receiving operations.

[0266] For example, in one implementation, the transceiver unit 1110 is used to perform... Figure 4 In the illustrated embodiments, steps S401, S403, S406, or S407, and / or the transceiver unit 1110, are further configured to execute other transceiver steps on the terminal device side in this application embodiment. The processing unit 1120 is configured to execute... Figure 4 In the illustrated embodiments, steps S404 and S408, and / or processing unit 1120 are also used to perform other processing steps on the terminal device side in the embodiments of this application.

[0267] When the communication device is a chip, the chip includes a transceiver unit and a processing unit. The transceiver unit can be an input / output circuit or a communication interface; the processing unit is a processor, microprocessor, or integrated circuit integrated on the chip.

[0268] When the communication device in this embodiment is a terminal device, it can be referred to Figure 12 The device shown. As an example, this device can perform similar tasks. Figure 10 The functionality of the 1020 processor. Figure 12The device includes a processor 1210, a data transmission processor 1220, and a data reception processor 1230. The processing module 801 in the above embodiment may be... Figure 12 The processor 1210 in the above embodiment performs the corresponding functions. The transceiver module 802 in the above embodiment can be... Figure 12 The transmitting data processor 1220 and / or receiving data processor 1230 are included. Although Figure 12 The diagram shows a channel encoder and a channel decoder, but it is understood that these modules are not limiting to this embodiment and are merely illustrative.

[0269] Figure 13 This illustrates another form of the present embodiment. The processing device 1300 includes modules such as a modulation subsystem, a central processing subsystem, and a peripheral subsystem. The communication device in this embodiment can serve as the modulation subsystem. Specifically, the modulation subsystem may include a processor 1303 and an interface 1304. The processor 1303 performs the functions of the aforementioned processing module 801, and the interface 1304 performs the functions of the aforementioned transceiver module 802. As another variation, the modulation subsystem includes a memory 1306, a processor 1303, and a program stored in the memory 1306 and executable on the processor. When the processor 1303 executes the program, it implements the method on the terminal device side in the above method embodiment. It should be noted that the memory 1306 may be non-volatile or volatile, and its location may be inside the modulation subsystem or within the processing device 1300, as long as the memory 1306 can be connected to the processor 1303.

[0270] As another embodiment of this invention, a computer-readable storage medium is provided, on which instructions are stored, which, when executed, perform the method on the terminal device side of the above method embodiment.

[0271] As another form of this embodiment, a computer program product containing instructions is provided, which, when executed, perform the method on the terminal device side of the above method embodiment.

[0272] When the device in this embodiment is a network device, the network device can be as follows: Figure 14 As shown, device 1400 includes one or more radio frequency units, such as a remote radio unit (RRU) 1410 and one or more baseband units (BBUs) (also referred to as digital units, DUs) 1420. The RRU 1410 can be referred to as a transceiver module, and... Figure 7Corresponding to the transceiver module 702, optionally, this transceiver module can also be called a transceiver, transceiver circuit, or transceiver unit, etc., and may include at least one antenna 1411 and radio frequency unit 1412. The RRU 1410 part is mainly used for transmitting and receiving radio frequency signals and converting radio frequency signals to baseband signals, such as for sending indication information to terminal equipment. The BBU 1410 part is mainly used for baseband processing and controlling the base station, etc. The RRU 1410 and BBU 1420 can be physically set together or physically separated, i.e., a distributed base station.

[0273] The BBU 1420 is the control center of the base station, also known as a processing module, and can communicate with... Figure 6 The corresponding processing module 601 is mainly used to complete baseband processing functions, such as channel coding, multiplexing, modulation, spreading, etc. For example, the BBU (processing module) can be used to control the base station to execute the operation process of the network device in the above method embodiment, such as generating the above-mentioned indication information.

[0274] In one example, the BBU 1420 can be composed of one or more single boards. Multiple boards can collectively support a single access standard wireless access network (such as an LTE network), or they can each support different access standards wireless access networks (such as LTE, 5G, or other networks). The BBU 1420 also includes a memory 1421 and a processor 1422. The memory 1421 is used to store necessary instructions and data. The processor 1422 is used to control the base station to perform necessary actions, such as controlling the base station to execute the operation procedures related to the network device in the above method embodiments. The memory 1421 and processor 1422 can serve one or more single boards. That is, each single board can have its own memory and processor, or multiple single boards can share the same memory and processor. Furthermore, each single board can also have necessary circuitry.

[0275] This application also provides a computer-readable storage medium including instructions that, when run on a computer, cause the computer to perform the method executed by the first network device or the second network device in the foregoing embodiments.

[0276] This application also provides a computer-readable storage medium including instructions that, when run on a computer, cause the computer to perform the method executed by the terminal device in the foregoing embodiments.

[0277] This application also provides a computer program product, including instructions that, when run on a computer, cause the computer to perform the method executed by the first network device or the second network device in the foregoing embodiments.

[0278] This application also provides a computer program product, including instructions that, when run on a computer, cause the computer to execute the method executed by the terminal device in the foregoing embodiments.

[0279] This application provides a chip system including a processor and potentially a memory, for implementing the functions of the terminal device described in the aforementioned method. The chip system may be composed of chips or may include chips and other discrete components.

[0280] This application provides a chip system including a processor and potentially a memory, for implementing the functions of the first network device described in the aforementioned method. The chip system can be composed of chips or may include chips and other discrete components.

[0281] This application provides a chip system including a processor and potentially a memory, for implementing the functions of the second network device described in the aforementioned method. The chip system can be composed of chips or may include chips and other discrete components.

[0282] This application provides a communication system, which includes the aforementioned first network device, and / or, a terminal device, and / or, a second network device.

[0283] The methods provided in this application can be implemented entirely or partially through software, hardware, firmware, or any combination thereof. When implemented in software, they can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be magnetic media (e.g., floppy disk, hard disk, magnetic tape), optical media (e.g., digital video disc (DVD)), or semiconductor media (e.g., SSD), etc.

[0284] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A communication method characterized by comprising: The method comprises: The first network device determines that a terminal device will enter a first area, the first area being an area in which the terminal device switches from the first network device to a second network device, or the first area being an area in which the first network device and the second network device jointly transmit; Before the terminal device enters the first area, the first network device sends first indication information to the terminal device, the first indication information being used to instruct measurement of a first tracking reference signal of the second network device, a measurement result of the first tracking reference signal being used to compensate for a time offset and / or a frequency offset of a first downlink signal of the second network device.

2. The method of claim 1, wherein, The first network device determines that a terminal device will enter a first area, comprising: The first network device receives information of a first reference signal reception quality from the terminal device; When a difference between the first reference signal reception quality and a reference signal reception quality of the terminal device in one or more neighboring areas is less than or equal to a first threshold value, the first network device determines that the terminal device will enter the first area.

3. The method of claim 1, wherein, The first network device determines that a terminal device will enter a first area, comprising: The first network device determines that the terminal device will enter the first area according to a moving direction of the terminal device and network topology information in which the first network device is located.

4. The method according to any one of claims 1 to 3, characterized in that, The method further comprises: The first network device receives first information from the terminal device, the first information indicating a first quantity and a second quantity, wherein the first quantity is a quantity of simultaneously activated transmission configuration indication states supported by the terminal device, and the second quantity is a quantity of simultaneously measured tracking reference signals supported by the terminal device, the transmission configuration indication state being used to indicate a correspondence between the tracking reference signal and service; When the first quantity is greater than or equal to 2 and the second quantity is greater than or equal to 2, the first network device determines that the terminal device has a capability of compensating for a time offset and a frequency offset according to a measurement result of the first tracking reference signal and a measurement result of a second tracking reference signal, the second tracking reference signal being a tracking reference signal of the first network device.

5. The method of claim 4, wherein Compensating for the time offset and the frequency offset according to the measurement result of the first tracking reference signal and the measurement result of the second tracking reference signal comprises increasing a filtering coefficient of a crystal oscillator on the time offset and the frequency offset according to the measurement result of the first tracking reference signal.

6. The method of any one of claims 1-3, wherein, The method further comprises: The first network device receives third indication information from the terminal device, the third indication information being used to indicate that the terminal device has a capability of compensating for a time offset and a frequency offset according to a measurement result of the first tracking reference signal and a measurement result of a second tracking reference signal, the second tracking reference signal being a tracking reference signal of the first network device.

7. The method of claim 6, wherein Compensating the time offset and the frequency offset according to the measurement result of the first tracking reference signal and the measurement result of the second tracking reference signal comprises increasing a filtering coefficient of the crystal oscillator to the time offset and the frequency offset according to the measurement result of the first tracking reference signal.

8. The method of any one of claims 1-3, wherein, The first indication information comprises at least one of an identifier of the first tracking reference signal or information of time-frequency resources carrying the first tracking reference signal.

9. The method of claim 8, wherein, Before the terminal device enters the first area, the method further comprises: The first network device receives a first message from the second network device, and the first message comprises the first indication information.

10. The method of claim 9, wherein, Before receiving the first message from the second network device, the method further comprises: The first network device sends a second message to the second network device, and the second message is used to request the first indication information.

11. A communication method, comprising: Comprise: Before a terminal device enters a first area, the terminal device receives first indication information from a first network device, the first indication information being used to instruct measurement of a first tracking reference signal of a second network device, wherein the first area is an area in which the terminal device switches from the first network device to the second network device, or the first area is an area in which the first network device and the second network device jointly transmit; The terminal device measures the first tracking reference signal to obtain a first measurement result, and the first measurement result is used to compensate a time offset and / or a frequency offset of a first downlink signal of the second network device; After the terminal device enters the first area, the terminal device receives the first downlink signal from the second network device; The terminal device demodulates the first downlink signal according to the first measurement result.

12. The method of claim 11, wherein, After the terminal device enters the first area, the method further comprises: The terminal device receives second indication information from the second network device, and the second indication information is used to instruct demodulation of the first downlink signal according to the first measurement result.

13. The method according to claim 11 or 12, characterized in that, The method further comprises: The terminal device sends first reference signal reception quality information to the first network device, and the first reference signal reception quality information is used to determine that the terminal device is going to enter the first area.

14. The method of claim 11 or 12, wherein, The method further comprises: The terminal device sends first information to the first network device, and the first information indicates a first quantity and a second quantity, and the first information is used to determine that the terminal device has a capability of compensating a time offset and a frequency offset according to the first measurement result and a measurement result of a second tracking reference signal, wherein the first quantity is a quantity of simultaneously activated transmission configuration indication states supported by the terminal device, the second quantity is a quantity of simultaneously measured tracking reference signals supported by the terminal device, the transmission configuration indication state is used to indicate a correspondence relationship between a tracking reference signal and a service, and the second tracking reference signal is a tracking reference signal of the first network device.

15. The method of claim 14, wherein Compensating for the time offset and the frequency offset according to the first measurement result and a measurement result of a second tracking reference signal includes increasing a filter coefficient of a crystal oscillator for the time offset and the frequency offset according to the first measurement result.

16. The method of claim 11 or 12, wherein, The method further includes: The terminal device sends third indication information to the first network device, the third indication information being used to indicate that the terminal device has the capability of compensating for the time offset and the frequency offset according to the first measurement result and a measurement result of a second tracking reference signal, the second tracking reference signal being a tracking reference signal of the first network device.

17. The method of claim 16, wherein Compensating for the time offset and the frequency offset according to the first measurement result and a measurement result of a second tracking reference signal includes increasing a filter coefficient of a crystal oscillator for the time offset and the frequency offset according to the first measurement result.

18. A method of communication, comprising: The method further includes: Before the terminal device enters the first area, the second network device sends a first message to the first network device, the first message including first indication information, the first indication information including at least one of an identity of a first tracking reference signal or information of time-frequency resources carrying the first tracking reference signal, the first area being an area in which the terminal device switches from the first network device to the second network device or an area in which the first network device and the second network device jointly transmit, the first indication information being used for the terminal device to measure the first tracking reference signal to obtain a first measurement result, the first measurement result being used for compensating for a time offset and / or a frequency offset of a first downlink signal of the second network device; After the terminal device enters the first area, the second network device sends second indication information and the first downlink signal to the terminal device, the second indication information being used to indicate that the first downlink signal is demodulated according to the first measurement result.

19. The method of claim 18, wherein, Before the second network device sends the first message to the first network device, the method further includes: The second network device receives a second message from the first network device, the second message being used to request the first indication information.

20. A communications device, characterized by The method further includes: The processing module is configured to determine that a terminal device is going to enter a first area, the first area being an area in which the terminal device switches from a first network device to a second network device or an area in which the first network device and the second network device jointly transmit; The transceiver module is configured to send first indication information to the terminal device before the terminal device enters the first area, the first indication information being used to indicate that a first tracking reference signal of the second network device is measured, a measurement result of the first tracking reference signal being used for compensating for a time offset and / or a frequency offset of a first downlink signal of the second network device.

21. The communication apparatus according to claim 20, wherein, The transceiver module is specifically configured to: receive information of a first reference signal received quality from the terminal device; The processing module is specifically configured to: determine that the terminal device is going to enter the first area when a difference between the first reference signal received quality and a reference signal received quality of the terminal device in one or more neighboring areas is less than or equal to a first threshold value.

22. The communication apparatus according to claim 20, wherein, The processing module is specifically configured to: According to the moving direction of the terminal device and network topology information of the first network device, determine that the terminal device is about to enter a first area.

23. The communication apparatus according to any one of claims 20-22, wherein, The transceiver module is further configured to: Receive first information from the terminal device, the first information indicating a first quantity and a second quantity, wherein the first quantity is a quantity of simultaneously activated transmission configuration indication states supported by the terminal device, and the second quantity is a quantity of simultaneously measured tracking reference signals supported by the terminal device, the transmission configuration indication state being used to indicate a correspondence between a tracking reference signal and service; The processing module is further configured to: When the first quantity is greater than or equal to 2 and the second quantity is greater than or equal to 2, determine that the terminal device has a capability of compensating for a time offset and a frequency offset according to a measurement result of the first tracking reference signal and a measurement result of a second tracking reference signal, the second tracking reference signal being a tracking reference signal of the first network device.

24. The communication apparatus according to claim 23, wherein Compensating for the time offset and the frequency offset according to the measurement result of the first tracking reference signal and the measurement result of the second tracking reference signal includes increasing a filtering coefficient of a crystal oscillator to the time offset and the frequency offset according to the measurement result of the first tracking reference signal.

25. The communication apparatus according to any one of claims 20-22, wherein, The transceiver module is further configured to: Receive third indication information from the terminal device, the third indication information being used to indicate that the terminal device has the capability of compensating for the time offset and the frequency offset according to the measurement result of the first tracking reference signal and the measurement result of the second tracking reference signal, the second tracking reference signal being a tracking reference signal of the first network device.

26. The communication apparatus according to claim 25, wherein Compensating for the time offset and the frequency offset according to the measurement result of the first tracking reference signal and the measurement result of the second tracking reference signal includes increasing a filtering coefficient of a crystal oscillator to the time offset and the frequency offset according to the measurement result of the first tracking reference signal.

27. The communication apparatus according to any one of claims 20-22, wherein, The first indication information includes at least one of an identifier of the first tracking reference signal or information of time-frequency resources carrying the first tracking reference signal.

28. The communication apparatus according to claim 27, wherein, Before the terminal device enters the first area, the transceiver module is further configured to: Receive a first message from the second network device, the first message including the first indication information.

29. The communication apparatus according to claim 28, wherein, Before receiving the first message from the second network device, the transceiver module is further configured to: Send a second message to the second network device, the second message being used to request the first indication information.

30. A communications device, characterized by Comprise: A transceiver module is configured to receive first indication information from a first network device before a terminal device enters a first area, the first indication information being used to indicate that a first tracking reference signal of a second network device is measured, wherein the first area is an area in which the terminal device switches from the first network device to the second network device, or the first area is an area in which the first network device and the second network device jointly transmit. a processing module, configured to measure the first tracking reference signal to obtain a first measurement result, the first measurement result being used for compensation of time offset and / or frequency offset of a first downlink signal of the second network device; the transceiver module is further configured to receive the first downlink signal from the second network device after the terminal device enters a first area; the processing module is further configured to demodulate the first downlink signal according to the first measurement result.

31. The communication apparatus according to claim 30, wherein after the terminal device enters a first area, the transceiver module is further configured to: receive second indication information from the second network device, the second indication information being used to indicate that the first downlink signal is demodulated according to the first measurement result.

32. The communication apparatus according to claim 30 or 31, wherein, the transceiver module is further configured to: send first reference signal receiving quality information to the first network device, the first reference signal receiving quality information being used to determine that the terminal device is about to enter the first area.

33. The communication apparatus according to claim 30 or 31, wherein, the transceiver module is further configured to: send first information to the first network device, the first information indicating a first quantity and a second quantity, the first information being used to determine that the terminal device has a capability of compensating time offset and frequency offset according to the first measurement result and a measurement result of a second tracking reference signal, wherein the first quantity is a quantity of simultaneously activated transmission configuration indication states supported by the terminal device, the second quantity is a quantity of simultaneously measured tracking reference signals supported by the terminal device, the transmission configuration indication state is used to indicate a correspondence relationship between a tracking reference signal and a service, and the second tracking reference signal is a tracking reference signal of the first network device.

34. The communication apparatus according to claim 33, wherein compensating time offset and frequency offset according to the first measurement result and a measurement result of a second tracking reference signal includes increasing a filtering coefficient of a crystal oscillator to time offset and frequency offset according to the first measurement result.

35. The communication apparatus according to claim 30 or 31, wherein, the transceiver module is further configured to: send third indication information to the first network device, the third indication information being used to indicate that the terminal device has a capability of compensating time offset and frequency offset according to the first measurement result and a measurement result of a second tracking reference signal, and the second tracking reference signal is a tracking reference signal of the first network device.

36. The communication apparatus according to claim 35, wherein compensating time offset and frequency offset according to the first measurement result and a measurement result of a second tracking reference signal includes increasing a filtering coefficient of a crystal oscillator to time offset and frequency offset according to the first measurement result.

37. A communications device, characterized by includes: The transceiver is configured to send, to a first network device, a first message before a terminal device enters a first area, the first message comprising first indication information, the first indication information comprising at least one of an identity of a first tracking reference signal or information of time-frequency resources carrying the first tracking reference signal, the first area being an area in which the terminal device switches from the first network device to a second network device or an area in which the first network device and the second network device jointly transmit, the first indication information being used for the terminal device to measure the first tracking reference signal to obtain a first measurement result, the first measurement result being used for compensation of a time offset and / or a frequency offset of a first downlink signal of the second network device. The transceiver is further configured to send, to the terminal device, second indication information and the first downlink signal after the terminal device enters the first area, the second indication information being used to indicate that the first downlink signal is demodulated according to the first measurement result.

38. The communication apparatus of claim 37, wherein Before the second network device sends the first message to the first network device, the transceiver is further configured to: receive a second message from the first network device, the second message being used to request the first indication information.

39. A communications device, characterized by The apparatus comprises: a processor coupled to a memory, the memory being configured to store programs or instructions, when the programs or instructions are executed by the processor, the apparatus is caused to perform the method according to any one of claims 1 to 10, or the method according to claim 18 or 19.

40. A communications device, characterized by The apparatus comprises: a processor coupled to a memory, the memory being configured to store programs or instructions, when the programs or instructions are executed by the processor, the apparatus is caused to perform the method according to any one of claims 11 to 17.

41. A communication system, characterized by The apparatus comprises the communication apparatus according to any one of claims 20 to 29, and / or the communication apparatus according to any one of claims 30 to 36, and / or the communication apparatus according to claim 37 or 38.

42. A computer-readable storage medium, characterized in that, The storage medium stores computer programs or instructions, when the computer programs or instructions are executed by the communication apparatus, the method according to any one of claims 1 to 19 is implemented.

43. A computer program product, characterised in that, The computer program product comprises instructions, when the instructions are executed, the method according to any one of claims 1 to 19 is implemented.

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