Method for feeding back CSI and communication device

Abstract

Provided are a method for feeding back CSI and a communication device, in the communication method, a terminal device can send a first CSI, and can receive first indication information indicating whether a second CSI is correctly received, if the second CSI is correctly received, the terminal device can determine a fourth CSI according to a measurement result of a third reference signal and the first CSI, and send the fourth CSI, and if the second CSI is correctly received, the terminal device feeds back the fourth CSI. And if the second CSI is not correctly received, the terminal device can determine the fourth CSI according to the measurement result of the third reference signal and the third CSI, so that when the first CSI fails to be sent, the network device can determine the measurement result of the third reference signal according to the third CSI and the fourth CSI, and thus, the transmission of the first CSI is failed. In this way, the problem that the determined measurement result of the third reference signal is inaccurate due to the fact that the network device continues to determine the measurement result of the third reference signal according to the first CSI and the fourth CSI is avoided, and the system performance can be improved.

Description

Technical Field

[0001] This application relates to the field of communications, and more particularly to a method and a communication device for feeding back CSI in the field of communications. Background Art

[0002] In a wireless communication system, massive multiple input multiple output (massive MIMO) technology can be used to improve system capacity and spectral efficiency. In MIMO technology, a terminal device needs to measure a reference signal sent by a network device and report channel state information (CSI). The network device sends data to the terminal device based on the CSI. To save overhead, when reporting the measurement result to the network device, the terminal device can report the current CSI based on the previously reported CSI. However, if the network device does not correctly receive the previously reported CSI of the terminal device, and the terminal device reports the current CSI based on the previously reported CSI, it will cause the network device to be unable to recover the current reported CSI from the previously reported CSI, resulting in the inability to send data to the terminal device based on the CSI and poor system performance. Summary of the Invention

[0003] In a first aspect, a method for feeding back CSI is provided, including: receiving and measuring a first reference signal, and sending a first CSI; receiving first indication information, where the first indication information is used to indicate whether a second CSI is correctly received, and the second CSI is the first CSI or the CSI after a third CSI before the first CSI; receiving and measuring a third reference signal, and sending a fourth CSI according to the first indication information. If the first indication information is used to indicate that the second CSI is correctly received, the fourth CSI is obtained based on the measurement result of the third reference signal and the first CSI. If the first indication information is used to indicate that the second CSI is not correctly received, the fourth CSI is obtained based on the measurement result of the third reference signal and the third CSI. The sending time of the third CSI is before the sending time of the first CSI, the third CSI corresponds to a second reference signal, and the reporting time of the first CSI is before the reporting time of the fourth CSI.

[0004] In the above solution, the terminal device can send the first CSI and can receive the first indication information on whether the second CSI is correctly received. The second CSI can be the first CSI or the CSI after the third CSI and before the first CSI. If the second CSI is correctly received, the terminal device can determine the fourth CSI based on the measurement result of the third reference signal and the first CSI and send the fourth CSI. If the second CSI is not correctly received, the terminal device can determine the fourth CSI based on the measurement result of the third reference signal and the third CSI. The third CSI can be the CSI before the first CSI. In this way, when the transmission of the first CSI fails, the network device can determine the measurement result of the third reference signal based on the third CSI and the fourth CSI, thus avoiding the problem that the network device continues to determine the measurement result of the third reference signal based on the first CSI and the fourth CSI, resulting in inaccurate measurement result of the third reference signal, and thereby improving the system performance.

[0005] Optionally, the first CSI is the CSI of the first reference signal. The third CSI is the CSI of the second reference signal. The fourth CSI is the CSI of the third reference signal.

[0006] Optionally, the first CSI can be obtained based on the measurement result of the first reference signal, or the first CSI can be obtained based on the measurement result of the first reference signal and the CSI before the first CSI.

[0007] Optionally, the second CSI can be the first CSI, and the terminal device can receive the first indication information indicating whether the first CSI is correctly received to determine the content included in the fourth CSI.

[0008] Optionally, the second CSI can be the CSI after the third CSI and before the first CSI, and the terminal device can receive the first indication information indicating whether the second CSI is correctly received to determine the content included in the fourth CSI.

[0009] In some possible implementation manners, the measurement result of the first reference signal includes the first combination coefficient of the first spatial-frequency basis combination obtained based on the first reference signal, and the first CSI includes the difference between the first combination coefficient and the second combination coefficient of the first spatial-frequency basis combination of the third CSI.

[0010] Optionally, if the measurement result of the first reference signal includes the first combination coefficient of the first spatial-frequency basis combination, the terminal device may obtain the first CSI based on the first combination coefficient of the first spatial-frequency basis combination and the CSI before the first CSI. For example, the terminal device may obtain the first CSI based on the first combination coefficient of the first spatial-frequency basis combination and the third CSI. Optionally, if the third CSI includes the second combination coefficient corresponding to the first spatial-frequency basis combination, the terminal device may determine the difference between the first combination coefficient and the second combination coefficient. The first CSI sent by the terminal device includes the difference between the first combination coefficient and the second combination coefficient.

[0011] Optionally, if the first indication information indicates that the first CSI is correctly received, the fourth CSI is obtained based on the measurement result of the third reference signal and the first CSI, and the network device may determine the measurement result of the third reference signal based on the fourth CSI and the first CSI. Optionally, the terminal device may perform a difference operation on the measurement result of the third reference signal and the first CSI to obtain the fourth CSI, and the network device may determine the measurement result of the third reference signal based on the difference included in the fourth CSI and the first CSI; if the first indication information indicates that the first CSI is not correctly received, the fourth CSI is obtained based on the measurement result of the third reference signal and the third CSI, and the network device may determine the measurement result of the third reference signal based on the fourth CSI and the third CSI. Optionally, the terminal device may perform a difference operation on the measurement result of the third reference signal and the third CSI to obtain the fourth CSI, and the network device may determine the measurement result of the third reference signal based on the difference included in the fourth CSI and the third CSI. Among them, the transmission time of the third CSI is before the transmission time of the first CSI, and the third CSI corresponds to the second reference signal. For example, the transmission time of the third CSI is at a transmission time before the transmission time of the first CSI. At this time, the third CSI and the first CSI may be two adjacent CSIs. Optionally, the third CSI is a CSI correctly received by the network device. That is, if the first CSI is not correctly received, the terminal device may determine the fourth CSI of the third reference signal based on the correctly received third CSI before the first CSI and the measurement result of the third reference signal. In this way, the accuracy of the fourth CSI transmission can be improved.

[0012] In some possible implementation manners, the second CSI is the first CSI, the measurement result of the first reference signal and the first CSI further include the third combination coefficient of the second spatial-frequency basis combination obtained according to the first reference signal, and the measurement result of the third reference signal includes the fourth combination coefficient of the first spatial-frequency basis combination and the fifth combination coefficient of the second spatial-frequency basis combination obtained according to the third reference signal;

[0013] If the first indication information is used to indicate that the second CSI is correctly received, the fourth CSI includes the difference between the fifth combination coefficient and the third combination coefficient and the fourth combination coefficient;

[0014] If the first indication information is used to indicate that the second CSI is not correctly received, the fourth CSI includes the difference between the fourth combination coefficient and the second combination coefficient and the fifth combination coefficient;

[0015] Wherein, the first spatial-frequency basis combination is different from the second spatial-frequency basis combination.

[0016] In the above solution, if the first indication information indicates that the second CSI is correctly received, the fourth CSI includes the difference between the fifth combination coefficient and the third combination coefficient and the fourth combination coefficient. That is, if the first indication information indicates that the second CSI is correctly received, the terminal device can determine the difference between the fifth combination coefficient and the third combination coefficient. On the corresponding network device side, the network device can determine the fifth combination coefficient based on the difference between the fifth combination coefficient and the third combination coefficient included in the fourth CSI and the third combination coefficient, and can also determine the fourth combination coefficient included in the fourth CSI. Therefore, the network device can determine that the measurement result of the third reference signal includes the fourth combination coefficient and the fifth combination coefficient; if the first indication information indicates that the second CSI is not correctly received, the fourth CSI includes the difference between the fourth combination coefficient and the second combination coefficient and the fifth combination coefficient. That is, if the first indication information group still indicates that the second CSI is not correctly received, the terminal device can determine the difference between the fourth combination coefficient and the second combination coefficient included in the third CSI. On the corresponding network device side, the network device can determine the fourth combination coefficient based on the difference between the fourth combination coefficient and the second combination coefficient included in the fourth CSI and the second combination coefficient, and can also determine the fifth combination coefficient included in the fourth CSI. Therefore, the network device can determine that the measurement result of the third reference signal includes the fourth combination coefficient and the fifth combination coefficient.

[0017] In some possible implementation manners, the second CSI is the CSI after the third CSI and before the first CSI, the measurement result of the first reference signal includes the third combination coefficient of the second spatial-frequency basis combination obtained according to the first reference signal, and the first CSI includes the difference between the third combination coefficient and the sixth combination coefficient of the second spatial-frequency basis combination of the second CSI.

[0018] In some possible implementation manners, the measurement result of the first reference signal and the first CSI further include a first combination coefficient of a first spatial-frequency basis combination obtained according to the first reference signal, the measurement result of the third reference signal includes a fourth combination coefficient of the first spatial-frequency basis combination and a fifth combination coefficient of a second spatial-frequency basis combination obtained according to the third reference signal, and the third CSI includes a second combination coefficient of the first spatial-frequency basis combination;

[0019] If the first indication information is used to indicate that the second CSI is correctly received, the fourth CSI includes the difference between the fourth combination coefficient and the first combination coefficient and the fifth combination coefficient;

[0020] If the first indication information is used to indicate that the second CSI is not correctly received, the fourth CSI includes the difference between the fourth combination coefficient and the second combination coefficient and the fifth combination coefficient;

[0021] Wherein, the first spatial-frequency basis combination is different from the second spatial-frequency basis combination.

[0022] In the above solution, if the first indication information indicates that the second CSI is correctly received, the fourth CSI is obtained based on the measurement result of the third reference signal and the first CSI. That is to say, the terminal device can determine the fourth CSI according to the measurement result of the third reference signal and the first CSI. Since the second CSI is correctly received, the first CSI obtained according to the second CSI may also be correctly received. Therefore, the terminal device can determine the fourth CSI according to the measurement result of the third reference signal and the first CSI. For example, the terminal device can determine that the fourth CSI includes the difference between the fourth combination coefficient of the first spatial-frequency basis combination and the first combination coefficient of the first spatial-frequency basis combination, and the fifth combination coefficient. Corresponding to the network device side, the network device can determine the fourth combination coefficient according to the difference between the fourth combination coefficient and the first combination coefficient included in the fourth CSI and the first combination coefficient, and can also determine the fifth combination coefficient included in the fourth CSI. Therefore, the network device can determine that the measurement result of the third reference signal includes the fourth combination coefficient and the fifth combination coefficient. If the first indication information indicates that the second CSI is not correctly received, the fourth CSI is obtained based on the measurement result of the third reference signal and the third CSI. That is to say, the terminal device can determine the fourth CSI according to the measurement result of the third reference signal and the third CSI. Since the second CSI is not correctly received, the first CSI obtained according to the second CSI is also incorrect. Since the third CSI before the second CSI is correct, the terminal device can determine the fourth CSI according to the measurement result of the third reference signal and the third CSI. For example, the terminal device can determine that the fourth CSI includes the difference between the fourth combination coefficient of the first spatial-frequency basis combination and the second combination coefficient corresponding to the first spatial-frequency basis combination of the third CSI, and the fifth combination coefficient. Corresponding to the network device side, the network device can determine the fourth combination coefficient according to the difference between the fourth combination coefficient and the second combination coefficient included in the fourth CSI and the second combination coefficient, and can also determine the fifth combination coefficient included in the fourth CSI. Therefore, the network device can determine that the measurement result of the third reference signal includes the fourth combination coefficient and the fifth combination coefficient.

[0023] In some possible implementation manners, before receiving and measuring the first reference signal and sending the first CSI, the method further includes: receiving and measuring the second reference signal to obtain the third CSI; sending the third CSI.

[0024] In the above solution, if the third CSI is the first CSI, the terminal device can also send the third CSI measured, that is to say, the terminal device can report the measurement result.

[0025] In some possible implementation manners, receiving the first indication information includes: receiving the first indication information through downlink control information.

[0026] In some possible implementations, the first CSI and the fourth CSI are the CSI of two adjacent reporting periods for periodic reporting or semi-persistent reporting.

[0027] In the above solution, the first CSI and the fourth CSI are the CSI of two adjacent reporting periods for periodic reporting, or the CSI of two adjacent reporting periods for semi-persistent reporting.

[0028] In some possible implementations, the first CSI and the fourth CSI are the CSI of two adjacent reporting moments for aperiodic reporting.

[0029] In some possible implementations, the reporting configuration identifier of the first CSI is the same as the reporting configuration identifier of the fourth CSI.

[0030] In the above solution, the terminal device can determine the association of the measurement results of the reference signals with the same reporting configuration identifier, that is, the terminal device can perform a differential operation based on the measurement results of the first reference signal and the measurement results of the third reference signal, so as to report the fourth CSI, avoiding the problem that the terminal device cannot determine which reference signal measurement results are associated.

[0031] In some possible implementations, the third CSI is correctly received.

[0032] Optionally, the first CSI and the fourth CSI include the combined coefficients of the spatial-frequency basis. Optionally, the spatial-frequency basis can be a DFT basis. Optionally, the spatial-frequency basis can be a basis based on the statistical eigen-subspace. Optionally, the reporting period of the spatial-frequency basis is greater than the reporting period of the combined coefficients.

[0033] Optionally, the terminal device can measure the first PMI obtained from the first reference signal. The first CSI includes the linear combined coefficients corresponding to the spatial eigen-subspace basis and the frequency-domain eigen-subspace basis of the first PMI; the terminal device can measure the third PMI obtained from the third reference signal. The fourth CSI includes the linear combined coefficients corresponding to the spatial eigen-subspace basis and the frequency-domain eigen-subspace basis of the third PMI; the terminal device can measure the second PMI obtained from the second reference signal. The third CSI includes the linear combined coefficients corresponding to the spatial eigen-subspace basis and the frequency-domain eigen-subspace basis of the second PMI.

[0034] In a second aspect, a method for providing channel state information (CSI) feedback is provided, including: transmitting a first reference signal and receiving first CSI; transmitting first indication information for indicating whether second CSI is correctly received, where the second CSI is the first CSI or the CSI after a third CSI and before the first CSI; transmitting a third reference signal and receiving fourth CSI; if the first indication information is used to indicate that the second CSI is correctly received, determining a measurement result of the third reference signal according to the fourth CSI and the first CSI; if the first indication information is used to indicate that the second CSI is not correctly received, determining a measurement result of the third reference signal according to the fourth CSI and the third CSI; a reception time of the third CSI is before a reception time of the first CSI, and the third CSI corresponds to a second reference signal.

[0035] In the above solution, the terminal device can transmit first CSI and can receive first indication information indicating whether second CSI is correctly received. The second CSI can be the first CSI or the CSI after a third CSI and before the first CSI. If the second CSI is correctly received, the terminal device can determine fourth CSI according to the measurement result of the third reference signal and the first CSI and transmit the fourth CSI. If the second CSI is not correctly received, the terminal device can determine fourth CSI according to the measurement result of the third reference signal and the third CSI. The third CSI can be the CSI before the first CSI. In this way, when the transmission of the first CSI fails, the network device can determine the measurement result of the third reference signal according to the third CSI and the fourth CSI, thus avoiding the problem that the network device continues to determine the measurement result of the third reference signal according to the first CSI and the fourth CSI, resulting in inaccurate determination of the measurement result of the third reference signal, and thereby improving the system performance.

[0036] In some possible implementation manners, the first CSI includes a difference between a first combination coefficient of a first spatial-frequency basis combination obtained according to a first reference signal and a second combination coefficient of a first spatial-frequency basis combination of the third CSI.

[0037] In some possible implementation manners, the second CSI is the first CSI, and the first CSI further includes a third combination coefficient of a second spatial-frequency basis combination obtained according to the first reference signal;

[0038] Among them, the step of if the first indication information is used to indicate that the second CSI is correctly received, determining a measurement result of the third reference signal according to the fourth CSI and the first CSI includes:

[0039] If the first indication information is used to indicate that the second CSI is correctly received, determine the fifth combination coefficient according to the difference between the fifth combination coefficient of the second spatial-frequency basis combination included in the fourth CSI and the third combination coefficient and the third combination coefficient, and determine the fourth combination coefficient of the first spatial-frequency basis combination included in the fourth CSI. The measurement result of the third reference signal includes the fifth combination coefficient and the fourth combination coefficient;

[0040] Among them, if the first indication information is used to indicate that the second CSI is not correctly received, determining the measurement result of the third reference signal according to the fourth CSI and the third CSI includes:

[0041] If the first indication information is used to indicate that the second CSI is not correctly received, determine the fourth combination coefficient according to the difference between the fourth combination coefficient of the first spatial-frequency basis combination included in the fourth CSI and the second combination coefficient and the second combination coefficient, and determine the fifth combination coefficient of the second spatial-frequency basis combination included in the fourth CSI. The measurement result of the third reference signal includes the fifth combination coefficient and the fourth combination coefficient;

[0042] Among them, the first spatial-frequency basis combination is different from the second spatial-frequency basis combination.

[0043] In some possible implementation manners, the second CSI is the CSI after the third CSI and before the first CSI. The first CSI includes the difference between the third combination coefficient of the second spatial-frequency basis combination obtained according to the first reference signal and the sixth combination coefficient of the second spatial-frequency basis combination of the second CSI.

[0044] In some possible implementation manners, the first CSI further includes the first combination coefficient of the first spatial-frequency basis combination obtained according to the first reference signal, and the third CSI includes the second combination coefficient of the first spatial-frequency basis combination;

[0045] Among them, if the first indication information is used to indicate that the second CSI is correctly received, determining the measurement result of the third reference signal according to the fourth CSI and the first CSI includes:

[0046] If the first indication information is used to indicate that the second CSI is correctly received, determine the fourth combination coefficient according to the difference between the fourth combination coefficient of the first spatial-frequency basis combination included in the fourth CSI and the first combination coefficient and the first combination coefficient, and determine the fifth combination coefficient of the second spatial-frequency basis combination included in the fourth CSI. The measurement result of the third reference signal includes the fifth combination coefficient and the fourth combination coefficient;

[0047] Wherein, if the first indication information is used to indicate that the second CSI is not correctly received, determining a measurement result of the third reference signal according to the fourth CSI and the third CSI includes:

[0048] If the first indication information is used to indicate that the second CSI is not correctly received, determining the fourth combination coefficient according to a difference between a fourth combination coefficient of a first spatial-frequency basis combination included in the fourth CSI and the second combination coefficient and the second combination coefficient, and determining a fifth combination coefficient of a second spatial-frequency basis combination included in the fourth CSI, where the measurement result of the third reference signal includes the fourth combination coefficient and the fifth combination coefficient;

[0049] Wherein, the first spatial-frequency basis combination is different from the second spatial-frequency basis combination.

[0050] In some possible implementation manners, before sending the first reference signal, it includes:

[0051] Sending a second reference signal;

[0052] Receiving the third CSI corresponding to the second reference signal.

[0053] In some possible implementation manners, sending the first indication information includes:

[0054] Sending the first indication information through downlink control information.

[0055] In some possible implementation manners, the first CSI and the fourth CSI are CSI of two adjacent reporting periods reported periodically or semi-persistently.

[0056] In some possible implementation manners, the first CSI and the fourth CSI are CSI of two adjacent reporting moments reported aperiodically.

[0057] In some possible implementation manners, a reporting configuration identifier of the first CSI is the same as a reporting configuration identifier of the fourth CSI.

[0058] In some possible implementation manners, the network device correctly receives the third CSI.

[0059] Specifically, for the description of the second aspect, reference may be made to the description of the first aspect, and details are not described in order to avoid redundancy.

[0060] In a third aspect, a communication device is provided, which has functions to implement any one of the above aspects. The functions can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above functions. For example, a transceiver module or unit, a processing module or unit, an acquisition module or unit, etc.

[0061] In a fourth aspect, an embodiment of the present application provides a communication device, including: a memory and a processor, where the memory is used to store a computer program; the processor is used to cause the communication device to execute the communication method described in any one of the above aspects when the computer program is called.

[0062] In a fifth aspect, an embodiment of the present application provides a chip system, which includes a processor, the processor is coupled to a memory, and the processor executes a computer program stored in the memory to implement the communication method described in any one of the above aspects.

[0063] Wherein, the chip system can be a single chip or a chip module composed of multiple chips.

[0064] In a sixth aspect, an embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the communication method described in any one of the above aspects.

[0065] In a seventh aspect, an embodiment of the present application provides a computer program product, when the computer program product runs on a communication device, it causes the communication device to execute the communication method described in any one of the above aspects.

[0066] It can be understood that the beneficial effects of the above third aspect to seventh aspect can refer to the relevant descriptions in the above first aspect and second aspect, and will not be elaborated here. Description of the Drawings

[0067] Figure 1 is a schematic diagram of a communication system provided by an embodiment of the present application.

[0068] Figure 2 is a schematic diagram of the process of CSI feedback provided by an embodiment of the present application.

[0069] Figure 3 is a schematic diagram of a method for feedback CSI provided by an embodiment of the present application.

[0070] Figure 4 is a schematic diagram of a combination coefficient provided by an embodiment of the present application.

[0071] Figure 5 is a schematic diagram of another combination coefficient provided by an embodiment of the present application.

[0072] Figure 6 It is a schematic diagram of another method for providing feedback CSI according to an embodiment of the present application.

[0073] Figure 7 It is a schematic diagram of another combination coefficient provided by an embodiment of the present application.

[0074] Figure 8 It is a schematic diagram of another combination coefficient provided by an embodiment of the present application.

[0075] Figure 9 It is a schematic diagram of a communication device provided by an embodiment of the present application.

[0076] Figure 10 It is a schematic diagram of another communication device provided by an embodiment of the present application. Detailed implementation manners

[0077] It should be understood that the classification of manners, situations, categories, and embodiments in the embodiments of the present application is only for the convenience of description and should not constitute a special limitation. Features in various manners, categories, situations, and embodiments can be combined without conflict.

[0078] It should also be understood that the "first", "second", and "third" in the embodiments of the present application are only for distinction and should not constitute any limitation to the present application. It should also be understood that in various embodiments of the present application, the magnitude of the sequence number of each process does not mean the order of execution, and the execution order of each process should be determined by its function and internal logic and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0079] In the embodiments of the present application, for the number of nouns, unless otherwise specified, it means "singular noun or plural noun", that is, "one or more". "At least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the preceding and following associated objects. For example, A / B means: A or B. "At least one of the following (items)" or its similar expressions refer to any combination of these items, including any combination of single item (s) or plural item (s). For example, at least one of a, b, or c means: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0080] In addition, the terms "including" and "having" and any variations thereof mentioned in the description of the present application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes other steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0081] It should be noted that in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0082] The methods and devices provided in the embodiments of the present application are based on the same or similar technical concepts. Since the principles for the methods and devices to solve problems are similar, the implementation of the device and the method can be referred to each other, and the repeated parts will not be elaborated.

[0083] Figure 1 It is a schematic diagram of a communication system applicable to the embodiments of the present application. As Figure 1 shown, the wireless communication system may include a network device 110 and communicate with one or more terminal devices (such as Figure 1 the terminal device 121 and the terminal device 122 shown). When the network device 110 sends a signal, the network device 110 is the transmitting end, and the terminal device 121 or the terminal device 122 is the receiving end. Conversely, when the terminal device 121 or the terminal device 122 sends a signal, the terminal device 121 or the terminal device 122 is the transmitting end, and the network device 110 is the receiving end. Optionally, the terminal device 121 and the terminal device 122 can also communicate. When the terminal device 121 sends a signal to the terminal device 122, the terminal device 121 is the transmitting end, and the terminal device 122 is the receiving end. Conversely, when the terminal device 122 sends a signal to the terminal device 121, the terminal device 122 is the transmitting end, and the terminal device 121 is the receiving end.

[0084] The terminal device 121 or the terminal device 122 may also be referred to as a terminal, a user equipment (UE), a mobile station (MS), a mobile terminal (MT), a roadside unit (RSU), etc. The terminal device in the embodiments of this application may be a mobile phone, a tablet computer (Pad), a computer with wireless transceiver function, a wearable device, a vehicle, a drone, a helicopter, an airplane, a ship, a robot, a robotic arm, a smart home device, a speaker, etc. It may also be a wireless terminal applied to scenarios such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IOT), virtual reality (VR), augmented reality (AR), industrial control, self-driving, remote medical, smart grid, transportation safety, smart city, smart wear, smart transportation, and smart home. In this application, the foregoing terminal device and the chip applicable to the foregoing terminal device are collectively referred to as the terminal device. It should be understood that the embodiments of this application do not limit the specific technologies and specific device forms adopted by the terminal device.

[0085] The network device 110 may be a device in a wireless network, and the network device 110 may also be referred to as a network apparatus. For example, the network device 110 may be a radio access network (RAN) node that connects a terminal device to a wireless network, and may also be referred to as an access network device. The network device 110 includes but is not limited to: evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (for example, home evolved NodeB, or home Node B, HNB), baseband unit (BBU), access point (AP) in a wireless fidelity (WIFI) system, wireless relay node, wireless backhaul node, transmission point (TP), reception point (RP), or transmission and reception point (TRP), etc. It may also be a network device in a 5G mobile communication system or a network device in other future network systems. For example, a next generation NodeB (gNB), transmission reception point (TRP), TP in an NR system; or, one or a group (including multiple antenna panels) of antenna panels of a base station in a 5G mobile communication system; or, the network device 110 may also be a network node that constitutes a gNB or a transmission point. For example, BBU, or distributed unit (DU), etc.

[0086] In some deployments, the network device 110 may include a centralized unit (CU) and a distributed unit (DU). The network device 110 may also include an active antenna unit (AAU). The CU implements some functions of the gNB, and the DU implements some functions of the gNB. For example, the CU is responsible for processing non-real-time protocols and services and implementing the functions of the radio resource control (RRC) layer. The DU is responsible for processing physical layer protocols and real-time services and implementing the functions of the radio link control (RLC) layer, the media access control (MAC) layer, and the physical (PHY) layer. In some deployments, the CU may also be divided into a centralized unit control plane (CU-CP) node and a centralized unit user plane (CU-UP) node. Among them, the CU-CP is responsible for control plane functions, and the CU-UP is responsible for user plane functions. For example, the CU-CP and the CU-UP may be implemented by different functional entities and connected through an E1 interface. The CU-CP and the CU-UP may be coupled with the DU to jointly complete the functions of the base station. The control plane CU-CP of the CU also includes a further split architecture, that is, the existing CU-CP is further split into CU-CP1 and CU-CP2. Among them, CU-CP1 includes various radio resource management functions, and CU-CP2 only includes radio resource control (RRC) functions and PDCP-C functions (i.e., the basic functions of control plane signaling at the packet data convergence protocol (PDCP) layer).

[0087] Figure 1 The communication system shown may apply to 4G, 5G, 6G, or future communication systems, etc. The embodiments of the present application do not limit this.

[0088] For the convenience of description in the following embodiments, the numbers of the devices are omitted. For example, "terminal device" means "terminal device 121 or terminal device 122", and "network device" means "network device 110".

[0089] In the embodiments of the present application, the terminal device and the network device are taken as examples for description. In actual applications, the embodiments of the present application can also be applied to other scenarios, such as satellite communication scenarios.

[0090] Before the network device sends data to the terminal device, the terminal device needs to measure the reference signal sent by the network device. The terminal device reports CSI to the network device, and the network device performs precoding based on the CSI, and then sends the precoded data to the terminal device. In this process, in order to reduce the overhead of the terminal device reporting CSI, the terminal device's current reported CSI can refer to the previous CSI. However, if the network device does not correctly receive the previous CSI, it will cause the network device to be unable to recover the current CSI based on the previous CSI, thus affecting the accuracy of precoding and resulting in a decline in system performance. For example, as Figure 2 shown, the network device can send measurement configuration information to the terminal device, and then send a reference signal (also called a pilot) to the terminal device according to the measurement configuration information. The terminal device receives and measures the reference signal according to the measurement configuration information, and the terminal device sends the measured CSI to the network device. The network device sends data to the terminal device according to the CSI of the terminal device. For example, CSI can include a precoding matrix indicator (PMI). In R15, when the terminal device reports PMI, the idea of spatial domain compression can be adopted. The terminal device can represent the main eigenvector of the measured channel by a linear combination of discrete Fourier transform (DFT) vectors in the spatial domain. The terminal device can report the index or identifier of the DFT vector, as well as the linear combination coefficient. In R16, when the terminal device reports PMI, the idea of spatial domain and frequency domain compression can be adopted. The terminal device can compress the measured channel separately in the spatial domain and the frequency domain, and approximately represent the precoding matrix of the measured channel by a spatial domain component matrix constructed by one or more spatial domain basis vectors and a frequency domain component matrix constructed by one or more frequency domain basis vectors. However, the terminal device needs to report the index or identifier of one or more spatial domain basis vectors, and also needs to report the index or identifier of one or more time domain basis vectors. At the same time, it also needs to report the full-band combined coefficient matrix corresponding to the spatial domain component matrix and the frequency domain component matrix. Since the spatial domain basis vector and the time domain basis vector are DFT vectors, the full-band combined coefficient matrix is not very sparse, resulting in a relatively large overhead for the terminal device to report the full-band combined coefficient matrix. In a possible implementation, a codebook based on statistical eigen-subspace is proposed. This codebook uses the frequency domain eigen-subspace basis and the spatial domain eigen-subspace basis of long-term statistics to approximate the measured channel or the main eigenvector of the channel. Since the eigen-subspace basis describes the statistical characteristics of the domain where the channel is located and changes slowly. Therefore, the terminal device can feedback the frequency domain eigen-subspace basis and the spatial domain eigen-subspace basis to the network device in a relatively long period, and feedback the linear combination coefficient corresponding to the spatial domain eigen-subspace basis and the frequency domain eigen-subspace basis in a short period. For example, assume that the terminal device is a single antenna and the number of antennas on the network device side is Nt , the number of frequency domain units is N f , the downlink channel H reconstructed by the terminal device dl can be expressed as H dl = SD2F H , where S = S'D1, where S is the spatial domain feature subspace basis of the long period and is an approximation of the spatial domain feature space basis of the downlink channel measured by the terminal device, with a size of N t ′K, S' is the basis (such as the DFT basis), with a size of N t ′B matrix, C1 is the spatial domain coefficient of the long period, with a size of B′K; F H = D3F' H , where F H is the frequency domain feature subspace basis of the long period and is an approximation of the frequency domain feature subspace basis of the downlink channel measured by the terminal device, with a size of D′N f , D3 is the frequency domain coefficient of the long period, with a size of E′T, F' is the basis (such as the DFT basis), with a size of T′N f . D2 is the matrix corresponding to the linear combination coefficient corresponding to the spatial domain feature subspace basis and the frequency domain feature subspace basis, with a size of K′E, where N t , N f , K, B, E, T are positive integers. The reporting periods of D1, S', D3, and F' are relatively long, for example, reported once every 300 ms, and the reporting period of D2 is relatively short, for example, reported once every 5 ms. As the number of antennas N t increases, K will also increase, so D2 will increase. Since the reporting period of D2 is short, it will also lead to a relatively large reporting overhead. To reduce the overhead of the reported linear combination coefficients, the terminal device can be based on a time-division differential reporting method. For example, the linear combination coefficient reported at time t2 can be differentiated from the linear combination coefficient reported at time t1, where t1 is the previous reporting time of t2. The terminal device can report the differential part, thereby saving overhead. The network device can restore the linear combination coefficient at time t2 based on the differential part and the linear combination coefficient reported at time t1. However, if the network device does not correctly receive the linear combination coefficient reported at time t1, but the terminal device still reports the differential part of the linear combination coefficient at time t2 compared with that at time t1, it will cause the network device to be unable to restore the linear combination coefficient at time t2, thus affecting the precoding of the downlink data by the network device and resulting in poor system performance.

[0091] In an embodiment of the present application, the terminal device may send a first CSI, and may receive first indication information on whether the first CSI is correctly received. If the first CSI is correctly received, the terminal device may determine a fourth CSI based on the measurement result of a third reference signal and the first CSI, and send the fourth CSI. If the second CSI is not correctly received, the terminal device may determine the fourth CSI based on the measurement result of the third reference signal and the third CSI. The third CSI may be the CSI before the first CSI. In this way, when the transmission of the first CSI fails, the network device may determine the measurement result of the third reference signal based on the third CSI and the fourth CSI, thus avoiding the problem that the network device still determines the measurement result of the third reference signal based on the first CSI and the fourth CSI, resulting in inaccurate measurement results of the third reference signal, and thereby improving the system performance.

[0092] The following combines Figure 3 to describe the CSI feedback method in the embodiments of the present application. As Figure 3 shown, method 300 includes:

[0093] S310, The network device sends a first reference signal, and the terminal device receives and measures the first reference signal.

[0094] Optionally, after measuring the first reference signal, the network device may obtain the measurement result of the first reference signal. Optionally, the measurement result of the first reference signal may include the first combination coefficient of the first spatial-frequency basis combination obtained according to the first reference signal. Optionally, the first spatial-frequency basis combination may be a partial spatial-frequency basis combination or all spatial-frequency basis combinations obtained by measuring the first reference signal. The embodiments of the present application do not limit this.

[0095] S320, The terminal device sends a first CSI, and the network device receives the first CSI.

[0096] Among them, the first CSI corresponds to the first reference signal. For example, the first CSI is obtained according to the measurement result of the first reference signal. Or the first CSI may be obtained according to the measurement result of the first reference signal and the CSI before the first CSI.

[0097] Optionally, if the measurement result of the first reference signal includes the first combination coefficient of the first spatial-frequency basis combination, the terminal device may obtain the first CSI according to the first combination coefficient of the first spatial-frequency basis combination and the CSI before the first CSI. For example, the terminal device may obtain the first CSI according to the first combination coefficient of the first spatial-frequency basis combination and the third CSI. Optionally, if the third CSI includes the second combination coefficient corresponding to the first spatial-frequency basis combination, the terminal device may determine the difference between the first combination coefficient and the second combination coefficient, and the first CSI sent by the terminal device includes the difference between the first combination coefficient and the second combination coefficient.

[0098] Optionally, the measurement result of the first reference signal may further include a third combination coefficient of a second spatial-frequency basis combination obtained according to the first reference signal. At this time, the first CSI may also include the third combination coefficient of the second spatial-frequency basis combination. That is to say, the first CSI may include not only the difference between the first combination coefficient of the first spatial-frequency basis combination and the second combination coefficient of the second spatial-frequency basis combination, but also the third combination coefficient of the second spatial-frequency basis combination. In this way, the third combination coefficient may correspond to the combination coefficient of the second spatial-frequency basis combination, which can improve the accuracy of the first CSI reporting to a certain extent. That is to say, the first CSI may include the difference between the combination coefficients of some spatial-frequency basis combinations and the combination coefficients of some spatial-frequency basis combinations. The foregoing describes the case where the first CSI corresponds to two spatial-frequency basis combinations. In some cases, the first CSI may correspond to more spatial-frequency basis combinations. For example, the first CSI may include the difference between the spatial-frequency basis combination 1 and the spatial-frequency basis combination 1 of other CSIs, the combination coefficient of the spatial-frequency basis combination 2, and the combination coefficient of the spatial-frequency basis combination 3.

[0099] Optionally, within a preset duration after S310, if the network device does not receive the first CSI or the first CSI decoding fails, it indicates that the first CSI is not correctly received; if the network device receives the first CSI and decodes it correctly within the preset duration after S310, it indicates that the first CSI is correctly received. That is to say, the first CSI in S320 may be a response to the first reference signal in S310.

[0100] S330, the network device sends the first indication information, and the terminal device receives the first indication information. The first indication information is used to indicate whether the first CSI is correctly received.

[0101] If the network device correctly receives the first CSI in S320, the first indication information indicates that the first CSI is correctly received. If the network device does not correctly receive the first CSI, the first indication information indicates that the first CSI is not correctly received.

[0102] Optionally, if the first CSI includes the difference between the first combination coefficient of the first spatial-frequency basis combination and the second combination coefficient corresponding to the first spatial-frequency basis combination of the third CSI, and the network device does not correctly receive the difference, it may send the first indication information to indicate that the first CSI is not correctly received; if the network device correctly receives the difference, it may send the first indication information, and the first indication information indicates that the first CSI is correctly received.

[0103] Optionally, if the first CSI includes the difference between the first combination coefficient of the first spatial-frequency basis combination and the second combination coefficient of the first spatial-frequency basis combination included in the third CSI, and includes the third combination coefficient of the second spatial-frequency basis combination, and the network device does not correctly receive the first CSI, it also means that the difference and the third combination coefficient included in the first CSI are not received. Then, the first indication information indicates that the first CSI is not correctly received; if the network device receives the difference and the third combination coefficient included in the first CSI, the first indication information indicates that the first CSI is correctly received.

[0104] Optionally, S330 includes the network device sending the first indication information through downlink control information (DCI), and the terminal device receiving the first indication information through DCI.

[0105] S340: The network device sends the third reference signal, and the terminal device receives the third reference signal and measures the third reference signal.

[0106] S350: The terminal device sends the fourth CSI, and the network device receives the fourth CSI.

[0107] Wherein, the fourth CSI corresponds to the third reference signal.

[0108] Among them, if the first indication information in S330 indicates that the first CSI is correctly received, the fourth CSI is obtained based on the measurement result of the third reference signal and the first CSI. The network device can determine the measurement result of the third reference signal according to the fourth CSI and the first CSI. Optionally, the terminal device can perform a differential operation on the measurement result of the third reference signal and the first CSI to obtain the fourth CSI. The network device can determine the measurement result of the third reference signal according to the difference included in the fourth CSI and the first CSI. If the first indication information in S330 indicates that the first CSI is not correctly received, the fourth CSI is obtained based on the measurement result of the third reference signal and the third CSI. The network device can determine the measurement result of the third reference signal according to the fourth CSI and the third CSI. Optionally, the terminal device can perform a differential operation on the measurement result of the third reference signal and the third CSI to obtain the fourth CSI. The network device can determine the measurement result of the third reference signal according to the difference included in the fourth CSI and the third CSI. Among them, the transmission time of the third CSI is before the transmission time of the first CSI, and the third CSI corresponds to the second reference signal. For example, the transmission time of the third CSI is one transmission time before the transmission time of the first CSI. At this time, the third CSI and the first CSI can be two adjacent CSIs. Optionally, the third CSI is a CSI correctly received by the network device. That is, if the first CSI is not correctly received, the terminal device can determine the fourth CSI of the third reference signal according to the correctly received third CSI before the first CSI and the measurement result of the third reference signal.

[0109] Optionally, the measurement result of the third reference signal includes a fourth combination coefficient of the first spatial-frequency basis combination and a fifth combination coefficient of the second spatial-frequency basis combination obtained according to the third reference signal.

[0110] Optionally, if the first indication information indicates that the second CSI is correctly received, the fourth CSI includes the difference between the fifth combination coefficient and the third combination coefficient and the fourth combination coefficient. That is, if the first indication information indicates that the second CSI is correctly received, the terminal device can determine the difference between the fifth combination coefficient and the third combination coefficient. On the corresponding network device side, the network device can determine the fifth combination coefficient according to the difference between the fifth combination coefficient and the third combination coefficient included in the fourth CSI and the third combination coefficient, and can also determine the fourth combination coefficient included in the fourth CSI. Therefore, the network device can determine that the measurement result of the third reference signal includes the fourth combination coefficient and the fifth combination coefficient. For example Figure 4As shown, time t1 is the reporting time of the third CSI corresponding to the second reference signal, time t2 is the reporting time of the first CSI corresponding to the first reference signal, time t3 is the reporting time of the fourth CSI corresponding to the third reference signal, the combination coefficient of the first space-frequency basis combination is C1, the combination coefficient of the second space-frequency basis combination is C2, and the measurement result of the second reference signal includes the second combination coefficient C of the first space-frequency basis combination 1,t1 The seventh combination coefficient C of the second space-frequency basis combination 2,t1 , the third CSI includes C 1,t1 and DC 2,t1 =C 2,t1 -C 2,t0 , the measurement result of the first reference signal includes the first combination coefficient C 1,t2 and the third combination coefficient C 2,t2 , the first CSI includes C 2,t2 (third combination coefficient) and DC 1,t2 =C 1,t2 -C 1,t1 (Difference between the first combination coefficient and the second combination coefficient). The measurement result of the third reference signal at time t3 includes the fourth combination coefficient C 1,t3 and the fifth combination coefficient C 2,t3 , if the first CSI is correctly received, the fourth CSI includes the fifth combination coefficient C 2,t3 and the third combination coefficient C 2,t2 Differential DC 2,t3 =C 2,t3 -C 2,t2 and the fourth combination coefficient C 1,t3 In this way, the network equipment can use the differential DC at time t3 2,t3 and the third combination coefficient C at time t2 2,t2 Calculate C at time t3 2,t3 , that is, C 2,t3 =DC 2,t3 +C 2,t2 , the fourth combination coefficient C can also be determined 1,t3 . The above description takes the example that the first space-frequency basis combination and the second space-frequency basis combination constitute the aforementioned spatial characteristic subspace basis and the frequency domain characteristic subspace basis. In some cases, more space-frequency basis combinations can constitute the spatial characteristic subspace basis and the frequency domain characteristic subspace basis; in other cases, one space-frequency basis combination can constitute the spatial characteristic subspace basis and the frequency domain characteristic subspace basis. In other words, the embodiment of the present application does not limit the number of space-frequency basis combinations that constitute the spatial characteristic subspace basis and the frequency domain characteristic subspace basis. Optionally, the spatial characteristic subspace basis and the frequency domain characteristic subspace basis can be DFT vectors.

[0111] Optionally, if the first indication information indicates that the second CSI is not correctly received, the fourth CSI includes the difference between the fourth combination coefficient and the second combination coefficient and the fifth combination coefficient. That is, if the first indication information indicates that the second CSI is not correctly received, the terminal device can determine the difference between the fourth combination coefficient and the second combination coefficient included in the third CSI. On the corresponding network device side, the network device can determine the fourth combination coefficient based on the difference between the fourth combination coefficient and the second combination coefficient included in the fourth CSI and the second combination coefficient, and can also determine the fifth combination coefficient included in the fourth CSI. Therefore, the network device can determine that the measurement result of the third reference signal includes the fourth combination coefficient and the fifth combination coefficient. For example Figure 5 As shown, where the reporting time of the third CSI corresponding to the second reference signal is time t1, the reporting time of the first CSI corresponding to the first reference channel is time t2, the reporting time of the fourth CSI corresponding to the third reference signal is time t3, the first spatial-frequency basis combination is C1, the second spatial-frequency basis combination is C2, and the measurement result of the second reference signal includes the second combination coefficient C 1,t1 and the seventh combination coefficient C 2,t1 , the third CSI includes C 1,t1 and DC 2,t1 =C 2,t1 -C 2,t0 , the measurement result of the first reference signal includes the first combination coefficient C 1,t2 and the third combination coefficient C 2,t2 , the first CSI includes C 2,t2 (the third combination coefficient) and DC 1,t2 =C 1,t2 -C 1,t1 (the difference between the first combination coefficient and the second combination coefficient). The measurement result of the third reference signal at time t3 includes the fourth combination coefficient C 1,t3 and the fifth combination coefficient C 2,t3 . If the first CSI is not correctly received, the fourth CSI includes the difference DC 1,t3 between the fourth combination coefficient C 1,t1 and the second combination coefficient C 1,t3 =C 1,t3 -C 1,t1 and the fifth combination coefficient C 2,t3 . In this way, the network device can calculate C 1,t3 at time t3 based on the difference DC 1,t1 at time t3 and the second combination coefficient C 1,t3 at time t1, that is, C 1,t3 =DC 1,t3 +C 1,t1 , and the network device can also determine the fifth combination coefficient C 2,t3The above description takes the example of forming the foregoing spatial domain feature subspace basis and frequency domain feature subspace basis with the first spatio-frequency basis combination and the second spatio-frequency basis combination. In some cases, more spatio-frequency basis combinations can form the spatial domain feature subspace basis and the frequency domain feature subspace basis; in other cases, one spatio-frequency basis combination can form the spatial domain feature subspace basis and the frequency domain feature subspace basis. In other words, the embodiments of the present application do not limit the number of spatio-frequency basis combinations forming the spatial domain feature subspace basis and the frequency domain feature subspace basis. Optionally, the spatial domain feature subspace basis and the frequency domain feature subspace basis can be DFT vectors.

[0112] Optionally, the third CSI can be the CSI sent for the first time. At this time, the third CSI can include the second combination coefficient of the first spatio-frequency basis combination and the seventh combination coefficient of the second spatio-frequency basis combination. That is to say, the network device can send the second reference signal, and the terminal device can measure the second reference signal to obtain the third CSI, and the third CSI can include the second combination coefficient of the first spatio-frequency basis combination and the seventh combination coefficient of the second spatio-frequency basis combination. For example, the third CSI is the CSI at time t0 in Figure 4 or Figure 5 . That is to say, if the third CSI is the CSI sent for the first time, then the third CSI can include the second combination coefficient C 1,t0 of the first spatial domain basis combination and the seventh combination coefficient C 2,t0 of the second spatial domain basis combination.

[0113] Optionally, the first CSI and the fourth CSI are the CSI of two adjacent reporting periods reported periodically. Optionally, the first CSI and the third CSI are the CSI of two adjacent periods reported periodically. Optionally, the terminal device can send the third CSI at the first moment, send the first CSI at the second moment, and send the fourth CSI at the third moment. The first moment is the reporting moment in the first reporting period, the second moment is the reporting moment in the second reporting period, and the third moment is the reporting moment in the third reporting period. The first reporting period and the second reporting period are two adjacent reporting periods of periodic reporting, and the second reporting period and the third reporting period are two adjacent reporting periods of periodic reporting.

[0114] Optionally, the first CSI and the fourth CSI are the CSI of two adjacent reporting periods reported semi-persistently. Optionally, the first CSI and the third CSI are the CSI of two adjacent reporting periods reported aperiodically. Optionally, the terminal device may send the third CSI at a first moment, the first CSI at a second moment, and the fourth CSI at a third moment. The first moment is the reporting moment in the first reporting period of semi-persistent reporting, the second moment is the reporting moment in the second reporting period of semi-persistent reporting, and the third moment is the reporting moment in the third reporting period of semi-persistent reporting. The first reporting period and the second reporting period are two adjacent reporting periods of semi-persistent reporting, and the second reporting period and the third reporting period are two adjacent reporting periods of semi-persistent reporting.

[0115] Optionally, the first CSI and the fourth CSI are the CSI of two adjacent reporting moments reported aperiodically. Optionally, the first CSI and the third CSI are the CSI of two adjacent reporting moments reported aperiodically. Optionally, the first DCI is used to trigger the terminal device to measure the second reference signal to obtain the third CSI. The terminal device may measure the second reference signal to obtain the third CSI according to the first reporting configuration identifier. The second DCI is used to trigger the terminal device to measure the first reference signal to obtain the first CSI. The terminal device may measure the first reference signal to obtain the first CSI according to the second reporting configuration identifier. The third DCI is used to trigger the terminal device to measure the third reference signal to obtain the fourth CSI. The terminal device may measure the third reference signal to obtain the fourth CSI according to the third reporting configuration identifier. Optionally, the first reporting configuration identifier is the same as the second reporting configuration identifier, so that the terminal device can determine the association of the measurement results of the reference signals with the same reporting configuration identifier, that is, the terminal device can perform a differential operation on the measurement result of the first reference signal corresponding to the second reporting configuration identifier and the measurement result of the second reference signal corresponding to the first reporting configuration identifier. Optionally, the second reporting configuration identifier is the same as the third reporting configuration identifier, so that the terminal device can determine the association of the measurement results of the reference signals with the same reporting configuration identifier, that is, the terminal device can perform a differential operation on the measurement result of the third reference signal corresponding to the third reporting configuration identifier and the measurement result of the first reference signal corresponding to the second reporting configuration identifier. Among them, the first reporting configuration identifier, the second reporting configuration identifier, and the third reporting configuration identifier may be configured by a radio resource control (RRC) message. Optionally, the first DCI and the second DCI are two adjacent DCIs. Optionally, the second DCI and the third DCI are two adjacent DCIs.

[0116] In the above method 300, the network device may receive the first indication information after sending the first CSI and before sending the fourth CSI. That is to say, the terminal device can know whether the first CSI before the fourth CSI is correctly received when sending the fourth CSI, so as to determine the content included in the fourth CSI. In some cases, there may be a delay in the first indication information sent by the network device, etc., which may cause the first indication information not to be sent to the terminal device immediately after the first CSI. The terminal device reports other CSIs after reporting the first CSI and before reporting the fourth CSI. The following combines Figure 6 to describe the CSI feedback method in the embodiments of the present application, as Figure 6 shown, the method 600 includes:

[0117] S610, the network device sends a second reference signal, and the terminal device receives and measures the second reference signal.

[0118] Optionally, after measuring the second reference signal, the terminal device may obtain the measurement result of the second reference signal. Optionally, the measurement result of the second reference signal may include the second combination coefficient of the first spatial-frequency basis combination obtained according to the second reference signal. Optionally, the measurement result of the second reference signal may further include the seventh combination coefficient of the second spatial-frequency basis combination obtained according to the second reference signal. Optionally, the first spatial-frequency basis combination may be a partial spatial-frequency basis combination or all spatial-frequency basis combinations obtained by measuring the second reference signal, and the embodiments of the present application do not limit this.

[0119] S620, the terminal device sends a third CSI, and the network device receives the third CSI.

[0120] Optionally, if the third CSI is the first sent CSI, the third CSI may include the second combination coefficient of the first spatial-frequency basis combination and the seventh combination coefficient of the second spatial-frequency basis combination. For example, if the third CSI is the CSI at the t0 moment in Figure 7 , the third CSI may include the second combination coefficient C of the first spatial-frequency basis 1,t0 and may also include the seventh combination coefficient C of the second spatial-frequency basis 2,t0 .

[0121] Optionally, if the third CSI is a non-first sent CSI, the third CSI may include the second combination coefficient, the difference between the combination coefficient of the first spatial-frequency basis of the CSI before the third CSI, and the seventh combination coefficient. For example, if the third CSI is the CSI at the t1 moment in Figure 7 , the third CSI may include the second combination coefficient C 1,t1 and the difference between C of the CSI at the t0 moment 1,t0 and the seventh combination coefficient C 2,t1; or it may include the difference between the seventh combination coefficient and the combination coefficient of the second spatial-frequency basis combination of the CSI before the third CSI, and the second combination coefficient. For example, if the third CSI is the CSI at time t1 in Figure 7 and the third CSI may include the seventh combination coefficient C 2,t1 and the difference between C of the CSI at time t0 and 2,t0 and the second combination coefficient C 1,t1 .

[0122] In S620, the network device can correctly receive the third CSI. After S620, the network device can send second indication information to the terminal device, and the second indication information is used to indicate that the third CSI is correctly received.

[0123] S630, the network device sends a fourth reference signal, and the terminal device receives and measures the fourth reference signal.

[0124] Optionally, after the terminal device measures the fourth reference signal, the measurement result of the fourth reference signal can be obtained. Optionally, the measurement result of the fourth reference signal may include an eighth combination coefficient of the first spatial-frequency basis combination obtained according to the fourth reference signal. Optionally, the measurement result of the fourth reference signal may further include a sixth combination coefficient of the second spatial-frequency basis combination obtained according to the fourth reference signal. Optionally, the first spatial-frequency basis combination may be a partial spatial-frequency basis combination or all of the spatial-frequency basis combinations obtained by measuring the fourth reference signal, and this application embodiment does not limit this.

[0125] S640, the terminal device sends a second CSI, and the network device receives the second CSI.

[0126] If the network device correctly receives the second CSI, the first indication information in S670 is used to indicate that the second CSI is correctly received; if the network device does not correctly receive the second CSI, the first indication information in S670 is used to indicate that the second CSI is not correctly received.

[0127] Optionally, the terminal device can determine the second CSI according to the measurement result of the fourth reference signal and the third CSI. For example, the difference between the measurement result of the fourth reference signal and the third CSI can be calculated, and the first CSI may include the difference between the measurement result of the first reference signal and the second CSI.

[0128] Optionally, the second CSI may include the difference between the eighth combination coefficient and the second combination coefficient of the first spatial-frequency basis combination of the third CSI before the second CSI, and the sixth combination coefficient, or may include the difference between the sixth combination coefficient and the seventh combination coefficient of the second spatial-frequency basis combination of the third CSI before the second CSI, and the eighth combination coefficient.

[0129] In S650, the network device sends a first reference signal, and the terminal device receives and measures the first reference signal.

[0130] Optionally, after the network device measures the first reference signal, a measurement result of the first reference signal can be obtained. Optionally, the measurement result of the first reference signal can include a third combination coefficient of a second spatial-frequency basis combination obtained according to the first reference signal and a first combination coefficient of a first spatial-frequency basis combination.

[0131] In S660, the terminal device sends a first CSI, and the network device receives the first CSI.

[0132] Among them, the terminal device can determine the first CSI according to the measurement result of the first reference signal and the second CSI. For example, the difference between the measurement result of the first reference signal and the second CSI can be calculated, and the first CSI can include the difference between the measurement result of the first reference signal and the second CSI.

[0133] Optionally, the terminal device can obtain the first CSI according to the first combination coefficient of the first spatial-frequency basis combination and the second CSI. For example, the terminal device can determine the difference between the first combination coefficient of the first spatial-frequency basis combination and the eighth combination coefficient of the first spatial-frequency basis combination included in the second CSI. The first CSI can include the difference between the first combination coefficient and the eighth combination coefficient and the third combination coefficient. Optionally, the terminal device can determine the difference between the third combination coefficient of the second spatial-frequency basis combination and the sixth combination coefficient of the second spatial-frequency basis combination included in the second CSI. The first CSI can include the difference between the third combination coefficient and the sixth combination coefficient and the first combination coefficient.

[0134] Optionally, if the terminal device also sends other CSIs between sending the second CSI and the first CSI, the terminal device can determine the difference between the first combination coefficient of the first spatial-frequency basis combination and the combination coefficient of the first spatial-frequency basis combination included in the other CSI. The first CSI can include the difference between the first combination coefficient and the combination coefficient of the first spatial-frequency basis combination included in the other CSI and the third combination coefficient. Optionally, the terminal device can determine the difference between the third combination coefficient of the second spatial-frequency basis combination and the combination coefficient of the second spatial-frequency basis combination included in the other CSI. The first CSI can include the difference between the third combination coefficient and the combination coefficient of the second spatial-frequency basis combination of the other CSI and the first combination coefficient.

[0135] In S670, the network device sends first indication information, and the terminal device receives the first indication information. The first indication information is used to indicate whether the second CSI is correctly received.

[0136] Optionally, S670 may be after S660 and before S680. That is, since the first indication information is received after the first CSI is sent, and the first CSI is determined based on the second CSI, if the first indication information is used to indicate that the second CSI is correctly received, it means that the first CSI is also correct; if the first indication information is used to indicate that the second CSI is not correctly received, it means that the first CSI is not correctly received either. Therefore, neither the first CSI nor the second CSI is correctly received.

[0137] At S680, the network device sends a third reference signal, and the terminal device receives and measures the third reference signal.

[0138] Optionally, the measurement result of the third reference signal may include a fourth combination coefficient of the first spatial-frequency basis combination and a fifth combination coefficient of the second spatial-frequency basis combination obtained from the third reference signal.

[0139] At S690, the terminal device sends a fourth CSI corresponding to the third reference signal according to the first indication information, and the network device receives the fourth CSI.

[0140] Optionally, if the first indication information indicates that the second CSI is correctly received, the fourth CSI is obtained based on the measurement result of the third reference signal and the first CSI. That is, the terminal device can determine the fourth CSI based on the measurement result of the third reference signal and the first CSI. Since the second CSI is correctly received, the first CSI obtained based on the second CSI may also be correctly received. Therefore, the terminal device can determine the fourth CSI based on the measurement result of the third reference signal and the first CSI. For example, the terminal device can determine that the fourth CSI includes the difference between the fourth combination coefficient of the first spatial-frequency basis combination and the first combination coefficient of the first spatial-frequency basis combination, and the fifth combination coefficient. On the network device side, the network device can determine the fourth combination coefficient based on the difference between the fourth combination coefficient and the first combination coefficient included in the fourth CSI and the first combination coefficient, and can also determine the fifth combination coefficient included in the fourth CSI. Therefore, the network device can determine that the measurement result of the third reference signal includes the fourth combination coefficient and the fifth combination coefficient. For example, as Figure 7 shown, where the reporting time of the third CSI corresponding to the second reference signal is t1, the reporting time of the second CSI corresponding to the fourth reference signal is t2, the reporting time of the first CSI corresponding to the first reference signal is t3, and the fourth CSI corresponding to the third reference signal is t4. The combination coefficient of the first spatial-frequency basis combination is C1, the combination coefficient of the second spatial-frequency basis combination is C2, and the measurement result of the second reference signal includes the second combination coefficient C of the first spatial-frequency basis combination obtained from the second reference signal 1,t1 and the seventh combination coefficient C of the second spatial-frequency basis combination 2,t1 , and the third CSI includes C1,t1 (Second combination coefficient) and DC 2,t1 = C 2,t1 - C 2,t0 (Difference between the seventh combination coefficient and C of the CSI at time t0 2,t0 . The measurement result of the fourth reference signal includes the eighth combination coefficient C 1,t2 of the first spatial-frequency basis combination obtained according to the fourth reference signal and the sixth combination coefficient C 2,t2 of the second spatial-frequency basis combination. The second CSI includes DC 1,t2 = C 1,t2 - C 1,t1 (Difference between the eighth combination coefficient C 1,t2 and the second combination coefficient C 1,t1 ) and the sixth combination coefficient C 2,t2 . The measurement result of the first reference signal includes the third combination coefficient C 2,t3 of the second spatial-frequency basis combination and the first combination coefficient C 1,t3 of the first spatial-frequency basis combination. The first CSI includes C 1,t3 (First combination coefficient) and DC 2,t3 = C 2,t3 - C 2,t2 (Difference between the third combination coefficient and the sixth combination coefficient). The measurement result of the third reference signal includes the fourth combination coefficient C 1,t4 of the first spatial-frequency basis combination and the fifth combination coefficient C 2,t4 of the second spatial-frequency basis combination. If the second CSI is correctly received, the fourth CSI includes C 2,t4 (Fifth combination coefficient) and DC 1,t4 = C 1,t4 - C 1,t3 (Difference between the fourth combination coefficient C 1,t4 and the first combination coefficient C 1,t3 ). In this way, the network device can calculate C 1,t4 at time t4 based on the differential DC 1,t3 at time t4 and the third combination coefficient C 1,t4 at time t3, and can also determine C 2,t4 in the fourth CSI, that is, C 1,t4 = DC 1,t4 + C 1,t3For example, the first spatial-frequency basis combination C1 and the second spatial-frequency basis combination C2 form the aforementioned spatial domain feature subspace basis and frequency domain feature subspace basis. The above description takes the first spatial-frequency basis combination and the second spatial-frequency basis combination forming the aforementioned spatial domain feature subspace basis and frequency domain feature subspace basis as an example. In some cases, more spatial-frequency basis combinations can form the spatial domain feature subspace basis and frequency domain feature subspace basis; in other cases, one spatial-frequency basis combination can form the spatial domain feature subspace basis and frequency domain feature subspace basis. In other words, the embodiments of the present application do not limit the number of spatial-frequency basis combinations forming the spatial domain feature subspace basis and frequency domain feature subspace basis. Optionally, the spatial domain feature subspace basis and frequency domain feature subspace basis can be DFT vectors.

[0141] Optionally, if the first indication information indicates that the second CSI is not correctly received, the fourth CSI is obtained according to the measurement result of the third reference signal and the third CSI. That is to say, the terminal device can determine the fourth CSI according to the measurement result of the third reference signal and the third CSI. Since the second CSI is not correctly received, the first CSI obtained according to the second CSI is also incorrect. Since the third CSI before the second CSI is correct, the terminal device can determine the fourth CSI according to the measurement result of the third reference signal and the third CSI. For example, the terminal device can determine that the fourth CSI includes the difference between the fourth combination coefficient of the first spatial-frequency basis combination and the second combination coefficient corresponding to the first spatial-frequency basis combination of the third CSI and the fifth combination coefficient. Corresponding to the network device side, the network device can determine the fourth combination coefficient according to the difference between the fourth combination coefficient and the second combination coefficient included in the fourth CSI and the second combination coefficient, and can also determine the fifth combination coefficient included in the fourth CSI. Therefore, the network device can determine that the measurement result of the third reference signal includes the fourth combination coefficient and the fifth combination coefficient. For example, as Figure 8 shown, where the reporting time of the third CSI corresponding to the second reference signal is t1, the reporting time of the second CSI corresponding to the fourth reference signal is t2, the reporting time of the first CSI corresponding to the first reference signal is t3, and the reporting time of the fourth CSI corresponding to the third reference signal is t4. The combination coefficient of the first spatial-frequency basis combination is C1, the combination coefficient of the second spatial-frequency basis combination is C2, and the measurement result of the second reference signal includes the second combination coefficient C 1,t1 of the first spatial-frequency basis combination obtained from the second reference signal and the seventh combination coefficient C 2,t1 of the second spatial-frequency basis combination. The third CSI includes C 1,t1 (the second combination coefficient) and DC 2,t1 = C 2,t1 - C 2,t0 (the difference between the seventh combination coefficient and C 2,t0(difference of the fourth reference signal). The measurement result of the fourth reference signal includes the eighth combination coefficient C of the first spatial-frequency basis combination obtained according to the fourth reference signal 1,t2 and the sixth combination coefficient C of the second spatial-frequency basis combination 2,t2 , the second CSI includes DC 1,t2 = C 1,t2 - C 1,t1 (the difference between the eighth combination coefficient C 1,t2 and the second combination coefficient C 1,t1 ) and the sixth combination coefficient C 2,t2 . The measurement result of the first reference signal includes the third combination coefficient C of the second spatial-frequency basis combination 2,t3 and the first combination coefficient C of the first spatial-frequency basis combination 1,t3 , the first CSI includes C 1,t3 (the first combination coefficient) and DC 2,t3 = C 2,t3 - C 2,t2 (the difference between the third combination coefficient and the sixth combination coefficient). The measurement result of the third reference signal includes the fourth combination coefficient C of the first spatial-frequency basis combination 1,t4 and the fifth combination coefficient C of the second spatial-frequency basis combination 2,t4 , if the second CSI is not correctly received, the fourth CSI includes C 2,t4 (the fifth combination coefficient) and DC 1,t4 = C 1,t4 - C 1,t1 (the difference between the fourth combination coefficient C 1,t4 and the second combination coefficient C 1,t1 ). In this way, the network device can calculate C at time t4 according to the difference DC 1,t4 at time t4 and the second combination coefficient C at time t1 1,t1 , that is, C 1,t4 , namely C 1,t4 = DC 1,t4 + C 1,t3 , and can also determine the C included in the fourth CSI 2,t4For example, the first spatial-frequency basis combination C1 and the second spatial-frequency basis combination C2 form the aforementioned spatial domain feature subspace basis and frequency domain feature subspace basis. The above description takes the first spatial-frequency basis combination and the second spatial-frequency basis combination forming the aforementioned spatial domain feature subspace basis and frequency domain feature subspace basis as an example. In some cases, more spatial-frequency basis combinations can form the spatial domain feature subspace basis and frequency domain feature subspace basis; in other cases, one spatial-frequency basis combination can form the spatial domain feature subspace basis and frequency domain feature subspace basis. In other words, the embodiments of the present application do not limit the number of spatial-frequency basis combinations forming the spatial domain feature subspace basis and frequency domain feature subspace basis. Optionally, the spatial domain feature subspace basis and frequency domain feature subspace basis can be DFT vectors.

[0142] Optionally, the third CSI and the second CSI are the CSI of two adjacent reporting periods reported periodically. Optionally, the second CSI and the first CSI are the CSI of two adjacent periods reported periodically. Optionally, the first CSI and the fourth CSI are the CSI of two adjacent periods reported periodically. Optionally, the terminal device can send the third CSI at the first moment, send the second CSI at the second moment, send the first CSI at the third moment, and send the fourth CSI at the fourth moment. The first moment is the reporting moment in the first reporting period, the second moment is the reporting moment in the second reporting period, the third moment is the reporting moment in the third reporting period, and the fourth moment is the reporting moment in the fourth reporting period. The first reporting period and the second reporting period are two adjacent reporting periods reported periodically, the second reporting period and the third reporting period are two adjacent reporting periods reported periodically, and the third reporting period and the fourth reporting period are two adjacent reporting periods.

[0143] Optionally, the third CSI and the second CSI are the CSI of two adjacent reporting periods reported semi-persistently. The second CSI and the first CSI are the CSI of two adjacent reporting periods reported semi-persistently. Optionally, the first CSI and the fourth CSI are the CSI of two adjacent reporting periods reported aperiodically. Optionally, the terminal device can send the third CSI at the first moment, send the second CSI at the second moment, send the first CSI at the third moment, and send the fourth CSI at the fourth moment. The first moment is the reporting moment in the first reporting period of semi-persistent reporting, the second moment is the reporting moment in the second reporting period of semi-persistent reporting, the third moment is the reporting moment in the third reporting period of semi-persistent reporting, and the fourth moment is the reporting moment in the fourth reporting period of semi-persistent reporting. The first reporting period and the second reporting period are two adjacent reporting periods of semi-persistent reporting, the second reporting period and the third reporting period are two adjacent reporting periods of semi-persistent reporting, and the third reporting period and the fourth reporting period are two adjacent reporting periods.

[0144] Optionally, the third CSI and the second CSI are CSI at two adjacent reporting moments of aperiodic reporting. Optionally, the second CSI and the first CSI are CSI at two adjacent reporting moments of aperiodic reporting. Optionally, the first CSI and the fourth CSI are CSI at two adjacent reporting moments of aperiodic reporting. Optionally, the first DCI is used to trigger the terminal device to measure the second reference signal to obtain the third CSI. The terminal device may measure the second reference signal to obtain the third CSI according to the first reporting configuration identifier. The second DCI is used to trigger the terminal device to measure the first reference signal to obtain the first CSI. The terminal device may measure the fourth reference signal to obtain the second CSI according to the second reporting configuration identifier. Optionally, the third DCI is used to trigger the terminal device to measure the first reference signal to obtain the first CSI. The terminal device may measure the first reference signal to obtain the first CSI according to the third reporting configuration identifier. Optionally, the fourth DCI is used to trigger the terminal device to measure the third reference signal to obtain the fourth CSI. Optionally, the fourth DCI is used to indicate the fourth reporting configuration identifier, and the terminal device may measure the third reference signal to obtain the fourth CSI according to the fourth reporting configuration identifier. Optionally, the first reporting configuration identifier is the same as the second reporting configuration identifier, so that the terminal device can determine the association of the measurement results of the reference signals with the same reporting configuration identifier, that is, the terminal device may perform a differential operation on the measurement result of the fourth reference signal corresponding to the second reporting configuration identifier and the measurement result of the second reference signal corresponding to the first reporting configuration identifier. Optionally, the second reporting configuration identifier is the same as the third reporting configuration identifier, so that the terminal device can determine the association of the measurement results of the reference signals with the same reporting configuration identifier, that is, the terminal device may perform a differential operation on the measurement result of the first reference signal corresponding to the third reporting configuration identifier and the measurement result of the fourth reference signal corresponding to the second reporting configuration identifier. Optionally, the third reporting configuration identifier is the same as the fourth reporting configuration identifier, so that the terminal device can determine the association of the measurement results of the reference signals with the same reporting configuration identifier, that is, the terminal device may perform a differential operation on the measurement result of the third reference signal corresponding to the fourth reporting configuration identifier and the measurement result of the first reference signal corresponding to the third reporting configuration identifier. Among them, the first reporting configuration identifier, the second reporting configuration identifier, and the third reporting configuration identifier may be configured by an RRC message. Optionally, the first DCI and the second DCI are two adjacent DCIs. Optionally, the second DCI and the third DCI are two adjacent DCIs. Optionally, the third DCI and the fourth DCI are two adjacent DCIs.

[0145] Optionally, the reference signal in the embodiments of the present application may be replaced with a pilot. For example, the first reference signal may be replaced with a first pilot, the second reference signal may be replaced with a second pilot, the third reference signal may be replaced with a third pilot, and so on.

[0146] Figure 9 is a schematic block diagram of a communication device provided by an embodiment of the present application. As Figure 9 shown, the communication device 900 may include a processing unit 910 and a communication unit 920. The communication unit 920 may implement corresponding communication functions, and the communication may be internal communication of the communication device 900 or communication between the communication device 900 and other devices; the processing unit 910 may implement corresponding processing functions. The communication unit 920 may also be referred to as a communication interface or a transceiver unit. Optionally, the communication device 900 may further include a storage unit, and the storage unit may be used to store instructions and / or data. The processing unit 810 may read the instructions and / or data in the storage unit so that the device implements the foregoing method embodiments.

[0147] In a possible design, the communication device 900 may be the terminal device in the foregoing method 300, or may also be a module or chip applied to the terminal device. The communication device 900 may be used to execute the steps or processes performed by the network device in the foregoing method 300 embodiments. Optionally, the communication device 900 may be the network device in the foregoing method 300, or may also be a module or chip applied to the network device. The communication device 900 may be used to execute the steps or processes performed by the network device in the foregoing method 300 embodiments.

[0148] In another possible design, the communication device 900 may be the terminal device in the foregoing method 600, or may also be a module or chip applied to the terminal device. The communication device 900 may be used to execute the steps or processes performed by the network device in the foregoing method 600 embodiments. Optionally, the communication device 900 may be the network device in the foregoing method 600, or may also be a module or chip applied to the network device. The communication device 900 may be used to execute the steps or processes performed by the network device in the foregoing method 600 embodiments.

[0149] Regarding the steps or processes performed by each unit in the communication device 900, reference may specifically be made to the embodiments of the foregoing method, which will not be elaborated here.

[0150] It should be understood that the "units" in the communication device 900 can be implemented by hardware, software, or hardware executing corresponding software. For example, the "units" can refer to application specific integrated circuits (ASICs), electronic circuits, processors (such as shared processors, dedicated processors, or group processors, etc.) for executing one or more software or firmware programs, and memories, combined logic circuits, and / or other suitable components supporting the described functions. For another example, the communication unit 920 can be replaced by a transceiver circuit (for example, which can include a receiving circuit and a transmitting circuit), and the processing unit 910 can be replaced by a processor or a processing circuit.

[0151] Figure 10 Fig. shows a schematic block diagram of another communication device 1000 provided by an embodiment of the present application. The communication device 1000 can be a terminal device or a network device, or can also be a chip, a chip system, or a processor, etc. that supports the terminal device or the network device to implement the above method. This device can be used to implement the method described in the above method embodiment, and for specific details, reference can be made to the description in the above method embodiment.

[0152] The communication device 1000 can include one or more processors 1010, which can also be referred to as processing units and can implement certain control functions. The processor 1010 can be a general-purpose processor or a dedicated processor, etc. For example, it can be a baseband processor or a central processing unit. The baseband processor can be used to process communication protocols and communication data, and the central processing unit can be used to control the communication device (such as a base station, a baseband chip, a user chip, a DU, or a CU, etc.), execute software programs, and process the data of the software programs.

[0153] In an alternative design, the processor 1010 can also store instructions and / or data, and the instructions and / or data can be run by the processor 1010, so that the communication device 1000 executes the method described in the above method embodiment. Optionally, the processing unit 910 in the communication device 900 can be the processor 1010.

[0154] In another alternative design, the communication device 1000 may include a communication interface 1020 for implementing receiving and transmitting functions. For example, the communication interface 1020 may be a transceiver circuit, an interface, an interface circuit, or a transceiver, etc. The transceiver circuit, interface, interface circuit, or transceiver for implementing receiving and transmitting functions may be separate or integrated together. The above-mentioned transceiver circuit, interface, interface circuit, or transceiver may be used for reading and writing code / data, or the above-mentioned transceiver circuit, interface, interface circuit, or transceiver may be used for signal transmission or transfer. Optionally, the communication unit 920 in the communication device 900 may be the communication interface 1020.

[0155] Optionally, the communication device 1000 may include one or more memories 1030 on which instructions may be stored and run on the processor 1010, so that the communication device 1000 executes the methods described in the above method embodiments. Optionally, data may also be stored in the memory 1030. Optionally, instructions and / or data may also be stored in the processor 1010. The processor 1010 and the memory 1030 may be provided separately or integrated together.

[0156] Those skilled in the art can understand that for ease of description, Figure 10 only one memory and one processor are shown. In an actual communication device, there may be multiple processors and memories. The memory may also be referred to as a storage medium or a storage device, etc., and the embodiments of the present application do not limit this.

[0157] For example, the processor may include a baseband processor and a central processor. The baseband processor is mainly used to process communication protocols and communication data, and the central processor is mainly used to control the entire terminal device, execute software programs, and process data of software programs. Figure 10 The processor in [the relevant context] integrates the functions of the baseband processor and the central processor. Those skilled in the art can understand that the baseband processor and the central processor may also be independent processors interconnected through technologies such as a bus. Those skilled in the art can understand that a terminal device may include multiple baseband processors to adapt to different network modes, a terminal device may include multiple central processors to enhance its processing ability, and various components of the terminal device may be connected through various buses. The baseband processor may also be referred to as a baseband processing circuit or a baseband processing chip. The central processor may also be referred to as a central processing circuit or a central processing chip. The function of processing communication protocols and communication data may be built into the processor or stored in a storage unit in the form of a software program, and the processor executes the software program to implement the baseband processing function.

[0158] It should be understood that, in a possible design, each step in the method embodiments provided in this application can be completed by the integrated logic circuit of the hardware in the processor or the instructions in software form. The steps of the method disclosed in combination with the embodiments of this application can be directly embodied as being executed and completed by the hardware processor, or executed and completed by the combination of the hardware and software modules in the processor. The software module can be located in a mature storage medium in the art such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, register, etc. This storage medium is located in the memory, and the processor reads the information in the memory and combines its hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0159] It should be noted that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method embodiments can be completed by the integrated logic circuit of the hardware in the processor or the instructions in software form. The above-mentioned processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in combination with the embodiments of this application can be directly embodied as being executed and completed by the hardware decoding processor, or executed and completed by the combination of the hardware and software modules in the decoding processor. The software module can be located in a mature storage medium in the art such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, register, etc. This storage medium is located in the memory, and the processor reads the information in the memory and combines its hardware to complete the steps of the above method.

[0160] It can be understood that the memory in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0161] The present application also provides a computer program product, which includes: computer program code. When the computer program code runs on a computer, it causes the computer to execute each step or process performed by the terminal device or the network device in any of the above method embodiments.

[0162] The present application also provides a computer-readable storage medium, which stores program code. When the program code runs on a computer, it causes the computer to execute each step or process performed by the terminal device or the network device in any of the above method embodiments.

[0163] The present application also provides a communication device, including a processor and an interface. The interface is used to send and / or receive signals, so that the processor executes each step or process performed by the terminal device or the network device in any of the above method embodiments.

[0164] The present application also provides a communication system, which includes a terminal device and a network device.

[0165] The above device embodiments and method embodiments exactly correspond to each other, and the corresponding steps are executed by the corresponding modules or units. For example, the communication unit or communication interface executes the steps of receiving or sending in the method embodiments, and other steps except for sending and receiving can be executed by the processing unit or processor.

[0166] In the embodiments of the present application, the terms and English abbreviations are all exemplary examples given for the convenience of description, and should not constitute any limitation to the present application. The present application does not exclude the possibility of defining other terms that can achieve the same or similar functions in existing or future protocols.

[0167] The terms "component", "module", "system", etc. used in this specification are used to represent computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, and / or a computer. By way of illustration, an application running on a computing device and the computing device can both be components. One or more components can reside in a process and / or an execution thread, and the components can be located on one computer and / or distributed between two or more computers. In addition, these components can be executed from various computer-readable storage media storing various data structures. The components can communicate, for example, through local and / or remote processes according to signals having one or more data packets (such as data from two components interacting with another component between a local system, a distributed system, and / or a network, such as the Internet interacting with other systems through signals).

[0168] Those of ordinary skill in the art can realize that the various illustrative logical blocks and steps described in connection with the embodiments disclosed herein can be implemented in electronic hardware, or in a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Skilled artisans can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the present application.

[0169] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can be based on the corresponding processes in the foregoing method embodiments, and will not be elaborated herein.

[0170] In several embodiments provided by this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling, direct coupling, or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the devices or units can be in electrical, mechanical, or other forms.

[0171] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0172] In addition, in each embodiment of this application, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0173] In the above embodiments, the functions of the functional units can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions (programs). When the computer program instructions (programs) are loaded and executed on a computer, the processes or functions described in the embodiments of this application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. 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 website, computer, server, or data center by wire (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that the computer can access or a data storage device such as a server or data center that includes one or more integrated available media. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium (for example, a solid state disk (SSD)).

[0174] When the above-mentioned functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of this application. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs.

[0175] As described above, the above are only specific implementation manners of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A method for feedback channel state information CSI, characterized in that, Comprising: Receiving and measuring a first reference signal and transmitting a first CSI; Receiving first indication information for indicating whether a second CSI is correctly received, where the second CSI is the first CSI or the second CSI is the CSI after a third CSI and before the first CSI; Receiving and measuring a third reference signal and transmitting a fourth CSI according to the first indication information. If the first indication information is used to indicate that the second CSI is correctly received, the fourth CSI is obtained based on the measurement result of the third reference signal and the first CSI. If the first indication information is used to indicate that the second CSI is not correctly received, the fourth CSI is obtained based on the measurement result of the third reference signal and the third CSI. The transmission time of the third CSI is before the transmission time of the first CSI. The third CSI corresponds to a second reference signal, and the reporting time of the first CSI is before the reporting time of the fourth CSI.

2. The method according to claim 1, characterized in that, The measurement result of the first reference signal includes a first combination coefficient of a first spatial-frequency basis combination obtained according to the first reference signal, and the first CSI includes the difference between the first combination coefficient and a second combination coefficient of the first spatial-frequency basis combination of the third CSI.

3. The method according to claim 2, wherein The second CSI is the first CSI. The measurement result of the first reference signal and the first CSI further include a third combination coefficient of a second spatial-frequency basis combination obtained according to the first reference signal. The measurement result of the third reference signal includes a fourth combination coefficient of the first spatial-frequency basis combination and a fifth combination coefficient of the second spatial-frequency basis combination obtained according to the third reference signal; If the first indication information is used to indicate that the second CSI is correctly received, the fourth CSI includes the difference between the fifth combination coefficient and the third combination coefficient and the fourth combination coefficient; If the first indication information is used to indicate that the second CSI is not correctly received, the fourth CSI includes the difference between the fourth combination coefficient and the second combination coefficient and the fifth combination coefficient; Wherein, the first spatial-frequency basis combination is different from the second spatial-frequency basis combination.

4. The method according to claim 1, wherein The second CSI is the CSI after the third CSI and before the first CSI. The measurement result of the first reference signal includes a third combination coefficient of a second spatial-frequency basis combination obtained according to the first reference signal, and the first CSI includes the difference between the third combination coefficient and a sixth combination coefficient of the second spatial-frequency basis combination of the second CSI.

5. The method according to claim 4, characterized in that, The measurement result of the first reference signal and the first CSI further include a first combination coefficient of a first spatial-frequency basis combination obtained according to the first reference signal. The measurement result of the third reference signal includes a fourth combination coefficient of the first spatial-frequency basis combination and a fifth combination coefficient of the second spatial-frequency basis combination obtained according to the third reference signal. The third CSI includes a second combination coefficient of the first spatial-frequency basis combination; If the first indication information is used to indicate that the second CSI is correctly received, the fourth CSI includes the difference between the fourth combining coefficient and the first combining coefficient and the fifth combining coefficient; If the first indication information is used to indicate that the second CSI is not correctly received, the fourth CSI includes the difference between the fourth combining coefficient and the second combining coefficient and the fifth combining coefficient; Wherein, the first spatial-frequency basis combination is different from the second spatial-frequency basis combination.

6. The method according to any one of claims 1 to 5, characterized in that, Before receiving and measuring the first reference signal and transmitting the first CSI, the method further includes: Receiving and measuring the second reference signal to obtain the third CSI; Transmitting the third CSI.

7. The method according to any one of claims 1 to 6, characterized in that, The receiving the first indication information includes: Receiving the first indication information through downlink control information.

8. The method according to any one of claims 1 to 7, characterized in that, The first CSI and the fourth CSI are the CSI of two adjacent reporting periods reported periodically or semi-persistently.

9. The method according to any one of claims 1 to 8, characterized in that The first CSI and the fourth CSI are the CSI of two adjacent reporting moments reported aperiodically.

10. The method according to claim 9, characterized in that, The reporting configuration identifier of the first CSI is the same as that of the fourth CSI.

11. The method according to any one of claims 1 to 10, characterized in that, The third CSI is correctly received.

12. A method for feedback channel state information CSI, characterized in that, Including: Transmitting a first reference signal and receiving a first CSI; Transmitting first indication information, the first indication information being used to indicate whether the second CSI is correctly received, the second CSI being the first CSI or the CSI after the third CSI and before the first CSI; Transmitting a third reference signal and receiving a fourth CSI; If the first indication information is used to indicate that the second CSI is correctly received, determining the measurement result of the third reference signal according to the fourth CSI and the first CSI; If the first indication information is used to indicate that the second CSI is not correctly received, determining the measurement result of the third reference signal according to the fourth CSI and the third CSI; the receiving moment of the third CSI is before the receiving moment of the first CSI, and the third CSI corresponds to the second reference signal.

13. The method according to claim 12, wherein The first CSI includes the difference between the first combining coefficient of the first spatial-frequency basis combination obtained according to the first reference signal and the second combining coefficient of the first spatial-frequency basis combination of the third CSI.

14. The method according to claim 13, wherein The second CSI is the first CSI, and the first CSI further includes a third combining coefficient of a second spatial-frequency basis combination obtained according to the first reference signal; Wherein, the if the first indication information is used to indicate that the second CSI is correctly received, determining the measurement result of the third reference signal according to the fourth CSI and the first CSI includes: If the first indication information is used to indicate that the second CSI is correctly received, determine the fifth combination coefficient according to the difference between the fifth combination coefficient of the second spatial-frequency basis combination included in the fourth CSI and the third combination coefficient and the third combination coefficient, and determine the fourth combination coefficient of the first spatial-frequency basis combination included in the fourth CSI. The measurement result of the third reference signal includes the fifth combination coefficient and the fourth combination coefficient; Among them, if the first indication information is used to indicate that the second CSI is not correctly received, determining the measurement result of the third reference signal according to the fourth CSI and the third CSI includes: If the first indication information is used to indicate that the second CSI is not correctly received, determine the fourth combination coefficient according to the difference between the fourth combination coefficient of the first spatial-frequency basis combination included in the fourth CSI and the second combination coefficient and the second combination coefficient, and determine the fifth combination coefficient of the second spatial-frequency basis combination included in the fourth CSI. The measurement result of the third reference signal includes the fifth combination coefficient and the fourth combination coefficient; Among them, the first spatial-frequency basis combination is different from the second spatial-frequency basis combination.

15. The method according to claim 12, wherein The second CSI is the CSI after the third CSI and before the first CSI. The first CSI includes the difference between the third combination coefficient of the second spatial-frequency basis combination obtained according to the first reference signal and the sixth combination coefficient of the second spatial-frequency basis combination of the second CSI.

16. The method according to claim 15, wherein The first CSI further includes the first combination coefficient of the first spatial-frequency basis combination obtained according to the first reference signal, and the third CSI includes the second combination coefficient of the first spatial-frequency basis combination; Among them, if the first indication information is used to indicate that the second CSI is correctly received, determining the measurement result of the third reference signal according to the fourth CSI and the first CSI includes: If the first indication information is used to indicate that the second CSI is correctly received, determine the fourth combination coefficient according to the difference between the fourth combination coefficient of the first spatial-frequency basis combination included in the fourth CSI and the first combination coefficient and the first combination coefficient, and determine the fifth combination coefficient of the second spatial-frequency basis combination included in the fourth CSI. The measurement result of the third reference signal includes the fifth combination coefficient and the fourth combination coefficient; Among them, if the first indication information is used to indicate that the second CSI is not correctly received, determining the measurement result of the third reference signal according to the fourth CSI and the third CSI includes: If the first indication information is used to indicate that the second CSI is not correctly received, determine the fourth combination coefficient according to the difference between the fourth combination coefficient of the first spatial-frequency basis combination included in the fourth CSI and the second combination coefficient and the second combination coefficient, and determine the fifth combination coefficient of the second spatial-frequency basis combination included in the fourth CSI, where the measurement result of the third reference signal includes the fourth combination coefficient and the fifth combination coefficient; Wherein, the first spatial-frequency basis combination is different from the second spatial-frequency basis combination.

17. The method according to any one of claims 12 to 16, characterized in that, Before sending the first reference signal, it includes: Sending a second reference signal; Receiving the third CSI corresponding to the second reference signal.

18. The method according to any one of claims 12 to 17, characterized in that, The sending of the first indication information includes: Sending the first indication information through downlink control information.

19. The method according to any one of claims 12 to 18, characterized in that, The first CSI and the fourth CSI are the CSIs of two adjacent reporting periods reported periodically or semi-persistently.

20. The method according to any one of claims 12 to 19, characterized in that, The first CSI and the fourth CSI are the CSIs of two adjacent reporting moments reported aperiodically.

21. The method according to claim 20, characterized in that, The reporting configuration identifier of the first CSI is the same as that of the fourth CSI.

22. The method according to any one of claims 12 to 21, characterized in that The network device correctly receives the third CSI.

23. A communication device, characterized in that, It includes a unit for executing the method according to any one of claims 1 to 22.

24. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, and when the computer program is run, it implements the method according to any one of claims 1 to 22.

25. A chip, characterized in that, It includes a processor, the processor is connected to a memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory so that the chip executes the method according to any one of claims 1 to 22.

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