Channel state information (CSI) reporting method and related device

Abstract

The invention relates to the technical field of wireless communication, in particular to a channel state information (CS) I reporting method and a related device. The method comprises the following steps: receiving a first channel state information reference signal CS I-RS and sending a first CSI. The first CS I comprises a first space-frequency joint vector set and indication information corresponding to at least one of a first space domain vector set and a first frequency domain vector set. The first space-frequency joint vector set is determined and obtained based on a second matrix obtained by vector sampling of the first matrix, the first space domain vector set and the first frequency domain vector set are determined and obtained based on the first matrix, and the first matrix is determined and obtained based on the first CS I-RS. And receiving the second CS I-RS and sending the second CS I. The second CS I comprises fourth indication information of the first weighting coefficient determined based on the first space-frequency joint vector set and the second CS I-RS. By adopting the method, the complexity and overhead of CS I reporting can be reduced.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technology, and in particular to a channel state information (CSI) reporting method and related devices. Background Art

[0002] The fifth generation (5G) mobile communication technology communication system has higher requirements for system capacity, spectrum efficiency, etc. In the 5G communication system, the application of large-scale multi-antenna technology plays a vital role in improving the spectrum efficiency of the system. When using multiple-input multiple-output (MIMO) technology, the network device needs to precode the data signal before sending the data to the terminal device. Normally, the network device needs to rely on the channel state information (CSI) of the downlink channel fed back by the terminal device to determine the precoding matrix used for channel precoding. Specifically, the CSI reported by the terminal device may include a precoding matrix indicator (PMI). The PMI is determined and reported based on a set of codebooks. The network device can determine the precoding matrix to be used based on the PMI and the codebook.

[0003] To improve the accuracy of PMI feedback, a codebook based on a statistical feature basis has been proposed for PMI reporting. This codebook uses the statistical feature basis and the corresponding linear combination coefficients to approximate the precoding matrix. The codebook can be joint in the spatial and frequency domains, that is, the precoding matrix is ​​represented by a linear combination of a set of space-frequency joint feature basis. Although this method can ensure the accuracy of CSI reporting, the complexity of the space-frequency joint statistical feature basis is very high, and the overhead of the corresponding basis indication information is also relatively large. This also leads to high complexity and high overhead in CSI reporting, which is not conducive to the efficient use of communication resources. Summary of the Invention

[0004] In order to solve the above problems, the present application provides a channel state information (CSI) reporting method and related devices, which can reduce the complexity and overhead of CSI reporting, thereby ensuring the rational use of communication resources.

[0005] The present application is introduced below from multiple aspects. It is easy to understand that the implementation methods of the following multiple aspects can refer to each other.

[0006] In a first aspect, the present application provides a method for reporting channel state information (CSI). The method may include: receiving a first channel state information reference signal (CSI-RS) from a network device; sending the first channel state information (CSI) to the network device. The first CSI includes first indication information of a first joint space-frequency vector set, and the first CSI also includes at least one of second indication information of a first spatial domain vector set and third indication information of a first frequency domain vector set. The first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling of a first matrix, the first spatial domain vector set and the first frequency domain vector set are determined based on the first matrix, and the first matrix is ​​determined based on the first CSI-RS. A second CSI-RS is received from the network device. Here, the first matrix and the first CSI-RS correspond to the same antenna port set and frequency domain element set. All elements contained in the second matrix are partial elements contained in the first matrix. In other words, the antenna port set corresponding to the second matrix is ​​a subset of the antenna port set corresponding to the first matrix, and / or the frequency domain element set corresponding to the second matrix is ​​a subset of the frequency domain element set corresponding to the first matrix. The second CSI is sent to the network device. The second CSI includes fourth indication information corresponding to the first weighting coefficient, and the first weighting coefficient is determined based on the first space-frequency joint vector set and the second CSI-RS.

[0007] In the above implementation, the first CSI reports the first joint space-frequency vector set and at least one of the first spatial vector set and the first frequency vector set, and the second CSI reports the first weighting coefficient corresponding to the first joint space-frequency vector set. On one hand, because the first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling from the first matrix, compared to the joint space-frequency vector set directly obtained based on the first matrix in the prior art, the complexity of the first joint space-frequency vector set reported in the present application is lower, the corresponding indication information occupies less overhead, and similarly, the corresponding weighting coefficient occupies less overhead. Therefore, the CSI reporting method provided in the present application has low complexity and low overhead. On the other hand, because the first CSI reports at least one of the first joint space-frequency vector set and the first spatial vector set and the first frequency vector set, the solution provided in the present application can still ensure the accuracy of CSI reporting. Therefore, the CSI reporting method provided in the present application can reduce the complexity and overhead of CSI reporting while ensuring the accuracy of CSI reporting. Therefore, by adopting the technical solution provided in this application, the problem of high complexity and high overhead of CSI reporting in the existing technology can be solved, which is conducive to the rational use of communication resources.

[0008] In conjunction with the first aspect, in one feasible implementation, when the first CSI includes first indication information and second indication information, the first matrix corresponds to the first antenna port set and the first frequency domain element set, and the second matrix corresponds to the second antenna port set and the first frequency domain element set. Furthermore, the second antenna port set is a subset of the first antenna port set, the first antenna port set includes multiple antenna ports corresponding to the first CSI-RS, and the first frequency domain element set includes multiple frequency domain elements occupied by the first CSI-RS.

[0009] In the above implementation, when only the vector of the spatial dimension is extracted for the first matrix, the network device does not need to use the first frequency domain vector set when reconstructing the matrix, so the first CSI only needs to report the first space-frequency joint vector set and the first spatial domain set. This can also avoid the waste of communication resources caused by reporting an invalid first frequency domain vector set.

[0010] In combination with the first aspect, in a feasible implementation manner, the second matrix is ​​obtained by performing vector sampling on the first matrix based on first information, and the first information is used to indicate a second antenna port set in the first antenna port set.

[0011] In conjunction with the first aspect, in one feasible implementation, the first information includes the number of antenna port intervals and an identifier of a starting antenna port, and the second antenna port set is determined by the terminal device in the first antenna port set according to the starting antenna port and the number of antenna port intervals. Optionally, this solution is applicable to a scenario in which uniform sampling of the first matrix in the spatial domain is performed.

[0012] In combination with the first aspect, in a feasible implementation, the first information includes a first bitmap, all bits in the first bitmap correspond one-to-one to all first antenna ports in the first antenna port set, all second antenna ports in the second antenna port set are all target first antenna ports in the first antenna port set, the bits corresponding to the target first antenna ports in the first antenna port set in the first bitmap are first values, and the bits corresponding to the first antenna ports other than the target first antenna ports in the first antenna port set in the first bitmap are second values, and the first value and the second value are different. In particular, this solution is applicable to scenarios where non-uniform sampling of the first matrix in the spatial domain is performed.

[0013] In combination with the first aspect, in a feasible implementation method, when the first CSI includes first indication information and third indication information, the first matrix corresponds to the first antenna port set and the first frequency domain unit set, the second matrix corresponds to the first antenna port set and the second frequency domain unit set, the second frequency domain unit set is a subset of the first frequency domain unit set, the first antenna port set includes multiple antenna ports corresponding to the first CSI-RS, and the first frequency domain unit set includes multiple frequency domain units occupied by the first CSI-RS.

[0014] In the above implementation, when only vector extraction of the frequency domain dimension is performed on the first matrix, the network device does not need to use the first spatial domain vector set when reconstructing the matrix, so the first CSI only needs to report the first spatial-frequency joint vector set and the first frequency-spatial domain set. This can also avoid the waste of communication resources caused by reporting an invalid first spatial domain vector set.

[0015] In combination with the first aspect, in a feasible implementation, the second matrix is ​​obtained by performing vector sampling on the first matrix based on second information, and the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

[0016] In combination with the first aspect, in a feasible implementation, the second information includes the number of frequency domain unit intervals and the identifier of the starting frequency domain unit, and the second frequency domain unit set is determined by the terminal device in the first frequency domain unit set according to the starting frequency domain unit and the number of frequency domain unit intervals.

[0017] In combination with the first aspect, in a feasible implementation method, the second information includes a second bit map, all bits in the second bit map correspond one-to-one to all first frequency domain units in the first frequency domain unit set, all second frequency domain units in the second frequency domain unit set are all target first frequency domain units in the first frequency domain unit set, and the bits corresponding to the target first frequency domain units in the first frequency domain unit set in the second bit map are third values, and the bits corresponding to the other first frequency domain units in the first frequency domain unit set except the target first frequency domain units in the first frequency domain unit set in the second bit map are fourth values, and the third value and the fourth value are different.

[0018] In conjunction with the first aspect, in a feasible implementation, when the first CSI includes first indication information, second indication information, and third indication information, the first matrix corresponds to the first antenna port set and the first frequency domain unit set, and the second matrix corresponds to the second antenna port set and the second frequency domain unit set. The second antenna port set is a subset of the first antenna port set, and the second frequency domain unit set is a subset of the first frequency domain unit set. The first antenna port set includes multiple antenna ports corresponding to the first CSI-RS, and the first frequency domain unit includes multiple frequency domain units occupied by the first CSI-RS.

[0019] In combination with the first aspect, in a feasible implementation method, the second matrix is ​​obtained by vector sampling the first matrix based on the first information and the second information, the first information is used to indicate the second antenna port set in the first antenna port set, and the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

[0020] It should be noted that, in this implementation, the specific implementation of the first information and the second information can be found in the above description of the first information and the second information, which will not be repeated here.

[0021] In conjunction with the first aspect, in one feasible implementation, the second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set. That is, the second CSI-RS and the first CSI-RS correspond to the same antenna port and frequency domain unit set. In this case, the first CSI-RS and the second CSI-RS can be the same CSI-RS, or the same type of CSI-RS transmitted at different times.

[0022] In conjunction with the first aspect, in one feasible implementation, the first weighting coefficient is determined based on the first joint space-frequency vector set and a third matrix. The third matrix is ​​obtained by vector sampling a fourth matrix, and the fourth matrix is ​​determined based on the second CSI-RS. The fourth matrix corresponds to the first antenna port set and the first frequency domain element set. In other words, the fourth matrix and the second CSI-RS correspond to the same antenna port set and frequency domain element set.

[0023] In conjunction with the first aspect, in one feasible implementation, when the first CSI includes first indication information and second indication information, the third matrix corresponds to the second antenna port set and the first frequency domain element set. When the first CSI includes first indication information and third indication information, the third matrix corresponds to the first antenna port set and the second frequency domain element set. When the first CSI includes first indication information, second indication information, and third indication information, the third matrix corresponds to the second antenna port set and the second frequency domain element set. That is, when the first space-frequency joint vector set is determined based on the first matrix sampled in the spatial dimension, the third matrix used to determine the first weighting coefficient should also be obtained by vector sampling of the fourth matrix based on the spatial dimension, and the vector sampling method for the fourth matrix is ​​consistent with the vector sampling method for the first matrix. Similarly, when the first space-frequency joint vector set is determined based on the first matrix sampled in the frequency domain dimension, or when the first space-frequency joint vector set is determined based on the first matrix sampled in both the spatial and frequency domain dimensions, it is also necessary to perform corresponding vector sampling operations on the fourth matrix to obtain the above-mentioned third matrix. This can reduce the complexity of determining the first weighting coefficient and reduce the overhead.

[0024] In combination with the first aspect, in a feasible implementation, the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same set of frequency domain units. In other words, the second CSI-RS is the sparse first CSI-RS, the antenna port set corresponding to the second CSI-RS is obtained by sampling the antenna port set corresponding to the first CSI-RS, and / or the frequency domain unit set corresponding to the second CSI-RS is obtained by sampling the frequency domain unit set corresponding to the first CSI-RS. Furthermore, the sampling method used is the same as the sampling method used for the second matrix.

[0025] In the above implementation, since the second CSI-RS is sparse, the number of corresponding antenna ports and / or the number of occupied frequency domain units are smaller, so the overhead occupied is smaller, which is more conducive to the rational use of communication resources.

[0026] In conjunction with the first aspect, in one feasible implementation, the first weighting coefficient is determined based on the first set of space-frequency joint vectors and a fourth matrix. The fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix and the second CSI-RS correspond to the same set of antenna ports and set of frequency domain elements.

[0027] In conjunction with the first aspect, in a feasible implementation, the first CSI-RS and the second CSI-RS have the same quasi-co-location relationship, or the first CSI-RS is quasi-co-located with the second CSI-RS. Alternatively, the first CSI-RS and the second CSI-RS can be configured in the same resource set (i.e., resource set).

[0028] In combination with the first aspect, in a feasible implementation, when the CSI reporting types corresponding to the first CSI report and the second CSI are periodic or semi-continuous, the CSI reporting period corresponding to the first CSI is greater than the CSI reporting period corresponding to the second CSI.

[0029] In the above implementation, the first CSI reports information indicating the statistical feature basis, which describes the statistical characteristics of the channel in its domain (such as the spatial domain, frequency domain, or joint space-frequency domain). This basis changes slowly and therefore does not require frequent reporting. Therefore, in the above implementation, setting the CSI reporting period corresponding to the first CSI report longer can reduce the number of first CSI reports, thereby conserving communication resources.

[0030] In combination with the first aspect, in a feasible implementation, when the CSI reporting types corresponding to the first CSI and the second CSI are both non-periodic, the CSI reporting interval corresponding to the first CSI reporting may be greater than the CSI reporting interval corresponding to the second CSI reporting.

[0031] In conjunction with the first aspect, in one feasible implementation, the first matrix may be a channel matrix for a certain antenna port of a terminal device or a precoding matrix for a certain stream / layer. Accordingly, when the first matrix is ​​a channel matrix, the fourth matrix is ​​also a channel matrix. When the first matrix is ​​a precoding matrix, the fourth matrix is ​​also a precoding matrix.

[0032] In combination with the first aspect, in a feasible implementation, when the second matrix is ​​obtained by vector sampling the first matrix based on the first information and / or the second information, the first information and / or the second information is provided by a network device.

[0033] In a second aspect, the present application provides a method for reporting channel state information (CSI). The method may include: sending a first channel state information reference signal (CSI-RS) to a terminal device. Receiving first channel state information (CSI) from the terminal device. The first CSI includes first indication information of a first joint space-frequency vector set, and at least one of second indication information of a first spatial domain vector set and third indication information of a first frequency domain vector set. The first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling of a first matrix, the first spatial domain vector set and the first frequency domain vector set are determined based on the first matrix, and the first matrix is ​​determined based on the first CSI-RS. Here, the first matrix and the first CSI-RS correspond to the same antenna port set and frequency domain element set. All elements contained in the second matrix are partial elements contained in the first matrix. In other words, the antenna port set corresponding to the second matrix is ​​a subset of the antenna port set corresponding to the first matrix, and / or the frequency domain element set corresponding to the second matrix is ​​a subset of the frequency domain element set corresponding to the first matrix. The second CSI-RS is sent to the terminal device. Second CSI is received from a terminal device, where the second CSI includes fourth indication information corresponding to a first weighting coefficient, and the first weighting coefficient is determined based on a first space-frequency joint vector set and a second CSI-RS.

[0034] In the above implementation, the network device can obtain the first space-frequency joint vector set and at least one of the first spatial domain vector set and the first frequency domain vector set reported by the terminal device through the first CSI, and obtain the first weighting coefficient corresponding to the first space-frequency joint vector set reported by the terminal device through the second CSI. On the one hand, because the first space-frequency joint vector set is determined based on the second matrix obtained by vector sampling of the first matrix, compared with the space-frequency joint vector set directly obtained based on the first matrix in the prior art, the complexity of the first space-frequency joint vector set reported in the solution of the present application is lower, the corresponding indication information occupies less overhead, and similarly, the corresponding weighting coefficient occupies less overhead. Therefore, the CSI reporting method provided by the present application has low complexity and low overhead. On the other hand, because the first CSI reports at least one of the first space-frequency joint vector set and the first spatial domain vector set and the first frequency domain vector set, the solution provided by the present application can still ensure the accuracy of CSI reporting. Therefore, the CSI reporting method provided by the present application can reduce the complexity and overhead of CSI reporting while ensuring the accuracy of CSI reporting. Therefore, by adopting the technical solution provided in this application, the problem of high complexity and high overhead of CSI reporting in the existing technology can be solved, which is conducive to the rational use of communication resources.

[0035] In conjunction with the second aspect, in one feasible implementation, the first weighting coefficient, the first joint space-frequency vector, and at least one of the first spatial vector set and the first frequency domain vector set are used to determine a fourth matrix, where the fourth matrix is ​​determined based on the second CS-RS. Alternatively, the first weighting coefficient, the first joint space-frequency vector set, and at least one of the first spatial vector set and the first frequency domain vector set are used to determine a fifth matrix corresponding to the second CSI-RS, where the fifth matrix is ​​the reconstructed fourth matrix.

[0036] In conjunction with the second aspect, in a feasible implementation, when the first CSI includes first indication information and second indication information, the first matrix corresponds to the first antenna port set and the first frequency domain unit set, the second matrix corresponds to the second antenna port set and the first frequency domain unit set, and the second antenna port set is a subset of the first antenna port set. The first antenna port set includes multiple antenna ports corresponding to the first CSI-RS, and the first frequency domain unit set includes multiple frequency domain units occupied by the first CSI-RS.

[0037] In combination with the second aspect, in a feasible implementation manner, the second matrix is ​​obtained by performing vector sampling on the first matrix based on the first information, and the first information is used to indicate the second antenna port set in the first antenna port set.

[0038] In combination with the second aspect, in a feasible implementation, when the second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set, the method further includes: determining the first space-frequency joint vector set, the first space domain vector set and the first weighting coefficient based on the first indication information, the second indication information and the fourth indication information. A third matrix is ​​determined based on the first weighting coefficient and the first space-frequency joint vector set, wherein the third matrix is ​​obtained based on vector sampling of the fourth matrix, the fourth matrix is ​​obtained based on the second CSI-RS, and the fourth matrix corresponds to the first antenna port set and the first frequency domain unit set. The fourth matrix is ​​determined based on the third matrix, the first space domain vector set and the first information. The first information is used to indicate the second antenna port set in the first antenna port set.

[0039] In combination with the second aspect, in a feasible implementation, when the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same frequency domain unit set, the method further includes: determining the first space-frequency joint vector set, the first space domain vector set, and the first weighting coefficient based on the first indication information, the second indication information, and the fourth indication information. Determine the fourth matrix based on the first weighting coefficient and the first space-frequency joint vector set, wherein the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix and the second CSI-RS correspond to the same antenna port set and frequency domain unit set. Determine the fifth matrix corresponding to the second CSI-RS based on the fourth matrix, the first space domain vector set, and the first information. The fifth matrix corresponds to the first antenna port set and the first frequency domain unit set, and the first information is used to indicate the second antenna port set in the first antenna port set.

[0040] In conjunction with the second aspect, in a feasible implementation, when the first CSI includes first indication information and third indication information, the first matrix corresponds to the first antenna port set and the first frequency domain unit set, and the second matrix corresponds to the first antenna port set and the second frequency domain unit set. The second frequency domain unit set is a subset of the first frequency domain unit set, the first antenna port set includes multiple antenna ports corresponding to the first CSI-RS, and the first frequency domain unit set includes multiple frequency domain units occupied by the first CSI-RS.

[0041] In combination with the second aspect, in a feasible implementation, when the second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set, the method further includes: determining the first space-frequency joint vector set, the first frequency domain vector set and the first weighting coefficient based on the first indication information, the third indication information and the fourth indication information. Determine the third matrix based on the first weighting coefficient and the first space-frequency joint vector set. The third matrix is ​​obtained based on vector sampling of the fourth matrix, the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix corresponds to the first antenna port set and the first frequency domain unit set. The fourth matrix is ​​determined based on the third matrix, the first frequency domain vector set and the second information, wherein the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

[0042] In combination with the second aspect, in a feasible implementation, when the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same frequency domain unit set, the method further includes: determining the first space-frequency joint vector set, the first frequency domain vector set and the first weighting coefficient according to the first indication information, the third indication information and the fourth indication information. Determine the fourth matrix according to the first weighting coefficient and the first space-frequency joint vector set, wherein the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix and the second CSI-RS correspond to the same antenna port set and frequency domain unit set. Determine the fifth matrix corresponding to the second CSI-RS according to the fourth matrix, the first frequency domain vector set and the second information, wherein the fifth matrix corresponds to the first antenna port set and the first frequency domain unit set, and the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

[0043] In conjunction with the second aspect, in a feasible implementation, when the first CSI includes first indication information, second indication information, and third indication information, the first matrix corresponds to the first antenna port set and the first frequency domain unit set, and the second matrix corresponds to the second antenna port set and the second frequency domain unit set. The second antenna port set is a subset of the first antenna port set, and the second frequency domain unit set is a subset of the first frequency domain unit set. The first antenna port set includes multiple antenna ports corresponding to the first CSI-RS, and the first frequency domain unit includes multiple frequency domain units occupied by the first CSI-RS.

[0044] In combination with the second aspect, in a feasible implementation method, the second matrix is ​​obtained by vector sampling the first matrix based on the first information and the second information, the first information is used to indicate the second antenna port set in the first antenna port set, and the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

[0045] In combination with the second aspect, in a feasible implementation, the second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set. The method also includes: determining the first space-frequency joint vector set, the first space domain vector set, the first frequency domain vector set and the first weighting coefficient based on the first indication information, the second indication information, the third indication information and the fourth indication information. Determine the third matrix based on the first weighting coefficient and the first space-frequency joint vector set, wherein the third matrix is ​​obtained based on vector sampling of the fourth matrix, the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix corresponds to the first antenna port set and the first frequency domain unit set. Determine the fourth matrix based on the third matrix, the first space domain vector set, the first frequency domain vector set and the first information and the second information, wherein the first information is used to indicate the second antenna port set in the first antenna port set, and the second information is used to indicate the second frequency domain unit in the first frequency domain unit.

[0046] In combination with the second aspect, in a feasible implementation, when the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same frequency domain unit set, the method further includes: determining a first space-frequency joint vector set, a first space domain vector set, a first frequency domain vector set, and a first weighting coefficient based on the first indication information, the second indication information, the third indication information, and the fourth indication information. Determining a fourth matrix based on the first weighting coefficient and the first space-frequency joint vector set, wherein the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix and the second CSI-RS correspond to the same antenna port set and frequency domain unit set. Determining a fifth matrix corresponding to the second CSI-RS based on the fourth matrix, the first space domain vector set, the first frequency domain vector set, the first information, and the second information. The fifth matrix corresponds to the first antenna port set and the first frequency domain unit set, the first information is used to indicate the second antenna port set in the first antenna port set, and the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

[0047] In combination with the second aspect, in a feasible implementation method, when the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix and the second CSI-RS and the second matrix correspond to the same set of frequency domain units, the first CSI-RS and the second CSI-RS have the same quasi-co-location relationship, or the first CSI-RS is quasi-co-located with the second CSI-RS.

[0048] In combination with the second aspect, in a feasible implementation, when the CSI reporting types corresponding to the first CSI and the second CSI are periodic or semi-continuous, the CSI reporting period corresponding to the first CSI is greater than the CSI reporting period corresponding to the second CSI.

[0049] In combination with the second aspect, in a feasible implementation, when the second matrix is ​​obtained by vector sampling the first matrix based on the first information and / or the second information, the first information and / or the third information is provided by the network device.

[0050] In a third aspect, the present application provides a method for reporting channel state information (CSI). The method includes: receiving a target first channel state information reference signal (CSI-RS) from a network device. Sending first channel state information (CSI) to the network device, wherein the first CSI includes first indication information of a first joint space-frequency vector set. The first CSI also includes at least one of the following: second indication information of the first spatial domain vector set, third indication information of the first frequency domain vector set, fifth indication information of the first time-space domain vector set, and sixth indication information of the first time-frequency domain vector set. The first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling of the first matrix, the first matrix is ​​determined based on the target first CSI-RS, and the first spatial domain vector set and the first frequency domain vector set are determined based on the first matrix. The first time-space domain vector set and / or the first time-frequency domain vector set are determined based on at least two first statistical information matrices. Any first statistical information matrix J of the at least two first statistical information matrices is determined based on N first CSI-RSs continuously received by the terminal device. N is a positive integer greater than or equal to 2. Receive a second CSI-RS from the network device. Second CSI is sent to the network device, where the second CSI includes fourth indication information corresponding to the first weighting coefficient, and the first weighting coefficient is determined based on the first space-frequency joint vector set and the second CSI-RS.

[0051] In the above implementation, the first CSI reports a first set of joint space-frequency vectors and at least one of the following: a first set of time-space domain vectors, a first set of time-frequency domain vectors, a first set of frequency domain vectors, and a first set of space domain vectors, and the second CSI reports a first weighting coefficient corresponding to the first set of joint space-frequency vectors. On the one hand, because the first set of joint space-frequency vectors is determined based on a second matrix obtained by vector sampling from the first matrix, compared to the prior art method of directly obtaining the set of joint space-frequency vectors based on the first matrix, the first set of joint space-frequency vectors reported in the scheme of the present application is less complex, the corresponding indication information occupies less overhead, and similarly, the corresponding weighting coefficient occupies less overhead. Therefore, the CSI reporting method provided by the present application has low complexity and low overhead. On the other hand, because the first CSI reports the first set of joint space-frequency vectors, the scheme provided by the present application can still ensure the accuracy of CSI reporting. Therefore, the CSI reporting method provided by the present application can reduce the complexity and overhead of CSI reporting while ensuring the accuracy of CSI reporting. Therefore, by adopting the technical solution provided in this application, the problem of high complexity and high overhead of CSI reporting in the existing technology can be solved, which is conducive to the rational use of communication resources.

[0052] In combination with the third aspect, in a feasible implementation method, the first weighting coefficient, the first space-frequency joint vector set, and at least one of the following: the first time-space domain vector set, the first time-frequency domain vector set, the first time-space domain vector set and the first frequency domain vector set, the first time-frequency domain vector set and the first space domain vector set, are used to determine the N sixth matrices corresponding to the N first moments, and the N first moments include at least the transmission moment of the second CSI-RS. Each sixth matrix in the above-mentioned N sixth matrices corresponds to a first antenna port set and a first frequency domain unit set. Among them, the first antenna port set includes multiple antenna ports corresponding to the target first CSI-RS. The first frequency domain unit set includes multiple frequency domain units occupied by the target first CSI-RS. Optionally, the above-mentioned N first moments can be the transmission moments of the N second CSI-RS indicated in the CSI reporting configuration information corresponding to the second CSI.

[0053] In the above implementation, the statistical basis and weighting coefficient reported by the first CSI and the second CSI can be used by the network device to determine the N sixth matrices corresponding to the N first moments including the transmission moment of the second CSI-RS. That is, the network device can determine the N sixth matrices based on the statistical basis reported by the terminal device through the first CSI and a weighting coefficient determined based on the first space-frequency joint vector set and the second CSI-RS reported through the second CSI. In the prior art, the network device needs to rely on the N reports of the weighting coefficients completed by the terminal device to determine the N sixth matrices. Therefore, compared with the prior art, the CSI reporting method provided in the present application can reduce the number of reports of the weighting coefficients corresponding to the space-frequency joint vector set, thereby further reducing the complexity and overhead of CSI reporting, and is more conducive to the rational use of communication resources.

[0054] In conjunction with the third aspect, in one feasible implementation, the first CSI includes first indication information and fifth indication information. The first matrix corresponds to the first antenna port set and the first frequency domain unit set, and the second matrix corresponds to the second antenna port set and the first frequency domain unit set. The second antenna port set is a subset of the first antenna port set, and the first antenna port set includes multiple antenna ports corresponding to the target first CSI-RS. The first frequency domain unit set includes multiple frequency domain units occupied by the target first CSI-RS.

[0055] In the above implementation, when only the vector of the spatial dimension is extracted for the first matrix, the network device does not need to use the first frequency domain vector set when reconstructing the matrix, so the first CSI only needs to report the first space-frequency joint vector set and the first time-space domain set. This can also avoid the waste of communication resources caused by reporting an invalid first time-frequency domain vector set.

[0056] In combination with the third aspect, in a feasible implementation manner, the second matrix is ​​obtained by performing vector sampling on the first matrix based on the first information, and the first information is used to indicate the second antenna port set in the first antenna port set.

[0057] In combination with the third aspect, in a feasible implementation method, the first information includes the antenna port interval number and the identifier of the starting antenna port, and the second antenna port set is determined by the terminal device in the second antenna port set according to the starting antenna port and the antenna port interval number.

[0058] In combination with the third aspect, in a feasible implementation method, the first information includes a first bit map, all bits in the first bit map correspond one-to-one to all first antenna ports in the first antenna port set, all second antenna ports in the second antenna port set are all target first antenna ports in the first antenna port set, and the bits corresponding to the target first antenna ports in the first antenna port set in the first bit map are first values. The bits corresponding to the first antenna ports other than the target first antenna ports in the first antenna port set in the first bit map are second values, and the first value and the second value are different.

[0059] In combination with the third aspect, in a feasible implementation method, the first CSI includes first indication information and sixth indication information, the first matrix corresponds to the first antenna port set and the first frequency domain unit set, the second matrix corresponds to the first antenna port set and the second frequency domain unit set, the second frequency domain unit set is a subset of the first frequency domain unit set, the first antenna port set includes multiple antenna ports corresponding to the target first CSI-RS, and the first frequency domain unit set includes multiple frequency domain units occupied by the target first CSI-RS.

[0060] In the above implementation, when only vector extraction of the frequency domain dimension is performed on the first matrix, the network device does not need to use the first spatial domain vector set when reconstructing the matrix, so the first CSI only needs to report the first spatial-frequency joint vector set and the first time-frequency domain set. This can also avoid the waste of communication resources caused by reporting an invalid first time-space domain vector set.

[0061] In combination with the third aspect, in a feasible implementation, the second matrix is ​​obtained by performing vector sampling on the first matrix based on second information, and the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

[0062] In combination with the third aspect, in a feasible implementation method, the second information includes the number of frequency domain unit intervals and the identifier of the starting frequency domain unit, and the second frequency domain unit set is determined by the terminal device in the first frequency domain unit set according to the starting frequency domain unit and the number of frequency domain unit intervals.

[0063] In combination with the third aspect, in a feasible implementation method, the second information includes a second bit map, all bits in the second bit map correspond one-to-one to all second frequency domain units in the first frequency domain unit set, all first frequency domain units in the second frequency domain unit set are all target first frequency domain units in the first frequency domain unit set, and the corresponding bits of each target first frequency domain unit in the first frequency domain unit set in the second bit map are third values, and the corresponding bits of each first frequency domain unit in the first frequency domain unit set except the target first frequency domain units in the first frequency domain unit set in the second bit map are fourth values, and the third value and the fourth value are different.

[0064] In conjunction with the third aspect, in a feasible implementation, the first CSI includes first indication information, fifth indication information, and third indication information, or the first CSI includes first indication information, sixth indication information, and second indication information. The first matrix corresponds to a first antenna port set and a first frequency domain unit set, the second matrix corresponds to a second antenna port set and a second frequency domain unit set, the second antenna port set is a subset of the first antenna port set, the second frequency domain unit set is a subset of the first frequency domain unit set, the first antenna port set includes multiple antenna ports corresponding to the target first CSI-RS, and the first frequency domain unit includes multiple frequency domain units occupied by the target first CSI-RS.

[0065] In combination with the third aspect, in a feasible implementation method, the second matrix is ​​obtained by vector sampling the first matrix based on the first information and the second information, the first information is used to indicate the second antenna port set in the first antenna port set, and the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

[0066] It should be understood that in this case, the specific implementation of the above-mentioned first information and second information can be found in the previous text and will not be repeated here.

[0067] In combination with the third aspect, in a feasible implementation method, the first statistical information matrix J is a statistical covariance matrix obtained by converting the seventh matrix, the seventh matrix is ​​composed of N eighth matrices, and the N eighth matrices are determined by the N first CSI-RSs corresponding to the first statistical information matrix J.

[0068] Furthermore, when the first CSI includes the fifth indication information, the seventh matrix corresponds to N first antenna port sets and one first frequency domain unit set. When the first CSI includes the sixth indication information, the seventh matrix corresponds to one first antenna port set and N first frequency domain unit sets.

[0069] In combination with the third aspect, in a feasible implementation, the first space-time domain vector set and the first time-frequency domain vector set are both determined by a second statistical information matrix, and the second statistical information matrix is ​​the mean of at least two first statistical information matrices.

[0070] In the above implementation, the mean of at least two first statistical information matrices is first calculated, and then the first time-space domain vector set and / or the first time-frequency domain vector set is determined based on the mean. The method is simple and easy to implement, which is conducive to reducing the complexity of CSI reporting.

[0071] In combination with the third aspect, in a feasible implementation, the second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set.

[0072] In conjunction with the third aspect, in one feasible implementation, the first weighting coefficient is determined based on the first space-frequency joint vector set and a third matrix. The third matrix is ​​obtained by vector sampling the fourth matrix. The fourth matrix is ​​a sixth matrix corresponding to the transmission time of the second CSI-RS in the N sixth matrices. The fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix corresponds to the first antenna port set and the first frequency domain unit set.

[0073] In conjunction with the third aspect, in a feasible implementation, when the first CSI includes the first indication information and the fifth indication information, the third matrix corresponds to the second antenna port set and the first frequency domain unit set. When the first CSI includes the first indication information and the sixth indication information, the third matrix corresponds to the first antenna port set and the second frequency domain unit set. When the first CSI includes the first indication information, the fifth indication information, and the third indication information, or when the first CSI includes the first indication information, the sixth indication information, and the second indication information, the third matrix corresponds to the second antenna port set and the second frequency domain unit set. That is, when the first space-frequency joint vector set is determined based on the first matrix sampled in the spatial dimension, the third matrix used to determine the first weighting coefficient should also be obtained by vector sampling of the fourth matrix based on the spatial dimension, and the vector sampling method for the fourth matrix is ​​consistent with the vector sampling method for the first matrix. Similarly, when the first space-frequency joint vector set is determined based on the first matrix sampled in the frequency domain dimension, or when the first space-frequency joint vector set is determined based on the first matrix sampled in both the spatial and frequency domain dimensions, it is also necessary to perform a corresponding vector sampling operation on the fourth matrix to obtain the above-mentioned third matrix. In this way, the complexity of determining the first weighting coefficient can be reduced and the overhead occupied can be small.

[0074] In combination with the third aspect, in a feasible implementation, the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same set of frequency domain units.

[0075] In the above implementation, since the second CSI-RS is sparse, the number of corresponding antenna ports and / or the number of occupied frequency domain units are smaller, so the overhead occupied is smaller, which is more conducive to the rational use of communication resources.

[0076] In combination with the third aspect, in a feasible implementation, the first weighting coefficient is determined based on the first space-frequency joint vector set and the fourth matrix, the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix corresponds to the same antenna port set and frequency domain unit set as the second CSI-RS. In this case, the N sixth matrices mentioned above are determined based on the first space-time domain vector set and / or the first time-frequency domain vector set, the first information and / or the second information, and the fourth matrix, and each of the N sixth matrices corresponds to the first antenna port set and the first frequency domain unit set.

[0077] In combination with the third aspect, in a feasible implementation method, when the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same set of frequency domain units, the target first CSI-RS and the second CSI-RS have the same quasi-co-location relationship, or the target first CSI-RS is quasi-co-located with the second CSI-RS.

[0078] In conjunction with the third aspect, in a feasible implementation, the transmission time of the second CSI-RS is indicated by the third information in the N first moments. That is, the third information can be used to indicate the transmission time of the second CSI-RS from the N first moments.

[0079] In conjunction with the third aspect, in a feasible implementation, the parameter N may be indicated by fourth information. Optionally, the fourth information is provided by a network device.

[0080] In combination with the third aspect, in a feasible implementation, when the second matrix is ​​obtained by vector sampling the first matrix based on the first information and / or the second information, the first information and / or the second information is provided by a network device.

[0081] In a fourth aspect, the present application provides a method for reporting channel state information (CSI). The method includes: sending a target first channel state information reference signal (CSI-RS) to a terminal device. Receiving first channel state information (CSI) from the terminal device, wherein the first CSI includes first indication information of a first joint space-frequency vector set, and at least one of the following: fifth indication information of a first time-space vector set, sixth indication information of a first time-frequency vector set, third indication information of a first frequency-domain vector set, and second indication information of the first space-domain vector set, wherein the first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling of a first matrix, the first matrix is ​​determined based on a target first CSI-RS, the first space-domain vector set and the first frequency-domain vector set are determined based on the first matrix, the first time-space vector set and / or the first time-frequency vector set are determined based on at least two first statistical information matrices, and any first statistical information matrix J of the at least two first statistical information matrices is determined based on N first CSI-RSs continuously received by the terminal device, where N is a positive integer greater than or equal to 2. Sending a second CSI-RS to the terminal device. Second CSI is received from a terminal device, where the second CSI includes fourth indication information corresponding to a first weighting coefficient, and the first weighting coefficient is determined based on a first space-frequency joint vector set and a second CSI-RS.

[0082] In combination with the fourth aspect, in a feasible implementation method, the first weighting coefficient, the first space-frequency joint vector set, and at least one of the following: the first time-space domain vector set, the first time-frequency domain vector set, the first frequency domain vector set, and the first space domain vector set are used to determine the N sixth matrices corresponding to the N first moments, and the N first moments include at least the transmission moment of the second CSI-RS. Each sixth matrix in the above-mentioned N sixth matrices corresponds to the first antenna port set and the first frequency domain unit set. Among them, the first antenna port set includes multiple antenna ports corresponding to the target first CSI-RS. The first frequency domain unit set includes multiple frequency domain units occupied by the target first CSI-RS.

[0083] In combination with the fourth aspect, in a feasible implementation method, the first CSI includes first indication information and fifth indication information, the first matrix corresponds to the first antenna port set and the first frequency domain unit set, the second matrix corresponds to the second antenna port set and the first frequency domain unit set, the second antenna port set is a subset of the first antenna port set, the first antenna port set includes multiple antenna ports corresponding to the target first CSI-RS, and the first frequency domain unit set includes multiple frequency domain units occupied by the target first CSI-RS.

[0084] In combination with the fourth aspect, in a feasible implementation manner, the second matrix is ​​obtained by performing vector sampling on the first matrix based on the first information, and the first information is used to indicate the second antenna port set in the first antenna port set.

[0085] In combination with the fourth aspect, in a feasible implementation method, the second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set, and the method further includes: determining the first space-frequency joint vector set, the first time-space domain vector set and the first weighting coefficient based on the first indication information, the fifth indication information and the third indication information. Determine the third matrix based on the first weighting coefficient and the first space-frequency joint vector set. The third matrix is ​​obtained based on vector sampling of the fourth matrix, the fourth matrix is ​​the sixth matrix corresponding to the transmission moment of the second CSI-RS in the N sixth matrices, the N sixth matrices correspond one-to-one to the N first moments, the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix corresponds to the first antenna port set and the first frequency domain unit set. Determine N sixth matrices based on the third matrix, the first time-space domain vector set and the first information, wherein the first information is used to indicate the second antenna port set in the first antenna port set.

[0086] In combination with the fourth aspect, in a feasible implementation, the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same frequency domain unit set. The method also includes: determining the first space-frequency joint vector set, the first time-space domain vector set, and the first weighting coefficient based on the first indication information, the fifth indication information, and the third indication information. Determine the fourth matrix based on the first weighting coefficient and the first space-frequency joint vector set, wherein the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix and the second CSI-RS correspond to the same antenna port set and frequency domain unit set. Determine N sixth matrices corresponding to N first moments based on the fourth matrix, the first space domain vector set, and the first information. The first information is used to indicate the second antenna port set from the first antenna port set, each sixth matrix corresponds to the first antenna port set and the first frequency domain unit set, and the N first moments include the transmission moment of the second CSI-RS.

[0087] In combination with the fourth aspect, in a feasible implementation, the second matrix is ​​obtained by performing vector sampling on the first matrix based on second information, and the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

[0088] In combination with the fourth aspect, in a feasible implementation, the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same frequency domain unit set. The method also includes: determining the first space-frequency joint vector set, the first time-frequency domain vector set and the first weighting coefficient based on the first indication information, the sixth indication information and the third indication information. Determine the fourth matrix based on the first weighting coefficient and the first space-frequency joint vector set, wherein the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix and the second CSI-RS correspond to the same antenna port set and frequency domain unit set. Determine N sixth matrices corresponding to N first moments based on the fourth matrix, the first time-frequency domain vector set and the second information. The second information is used to indicate the second frequency domain unit set from the first frequency domain unit set, and each sixth matrix corresponds to the first antenna port set and the first frequency domain unit set.

[0089] In combination with the fourth aspect, in a feasible implementation method, the first CSI includes first indication information, fifth indication information and third indication information, the first matrix corresponds to the first antenna port set and the first frequency domain unit set, the third matrix corresponds to the second antenna port set and the second frequency domain unit set, the second antenna port set is a subset of the first antenna port set, the second frequency domain unit set is a subset of the first frequency domain unit set, the first antenna port set includes multiple antenna ports corresponding to the target first CSI-RS, and the first frequency domain unit includes multiple frequency domain units occupied by the target first CSI-RS.

[0090] In combination with the fourth aspect, in a feasible implementation, the second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set, and the method further includes: determining the first space-frequency joint vector set, the first time-space domain vector set, the first frequency domain vector set, and the first weighting coefficient based on the first indication information, the fifth indication information, the third indication information, and the fourth indication information. Determine the third matrix based on the first weighting coefficient and the first space-frequency joint vector set. The third matrix is ​​obtained based on vector sampling of the fourth matrix, the fourth matrix is ​​the sixth matrix corresponding to the transmission moment of the second CSI-RS in the N sixth matrices, the N sixth matrices correspond one-to-one to the N first moments, the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix corresponds to the first antenna port set and the first frequency domain unit set. Determine N sixth matrices based on the third matrix, the first time-space domain vector set, the first frequency domain vector set, the first information, and the second information, wherein the first information is used to indicate the second antenna port set in the first antenna port set, and the second information is used to indicate the second frequency domain unit in the first frequency domain unit.

[0091] In combination with the fourth aspect, in a feasible implementation, the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same frequency domain unit set. The method also includes: determining the first space-frequency joint vector set, the first time-space domain vector set, the first frequency domain vector set and the first weighting coefficient based on the first indication information, the fifth indication information, the third indication information and the second indication information. Determine the fourth matrix based on the first weighting coefficient and the first space-frequency joint vector set, wherein the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix and the second CSI-RS correspond to the same antenna port set and frequency domain unit set. Determine N sixth matrices corresponding to N first moments based on the fourth matrix, the first time-space domain vector set, the first frequency domain vector set, the first information and the second information, wherein the first information is used to indicate the second antenna port set in the first antenna port set, and the second information is used to indicate the second frequency domain unit in the first frequency domain unit.

[0092] In combination with the fourth aspect, in a feasible implementation method, the first CSI includes first indication information, sixth indication information and second indication information, the first matrix corresponds to the first antenna port set and the first frequency domain unit set, the second matrix corresponds to the second antenna port set and the second frequency domain unit set, the second antenna port set is a subset of the first antenna port set, the second frequency domain unit set is a subset of the first frequency domain unit set, the first antenna port set includes multiple antenna ports corresponding to the target first CSI-RS, and the first frequency domain unit includes multiple frequency domain units occupied by the target first CSI-RS.

[0093] In combination with the fourth aspect, in a feasible implementation, the second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set, and the method further includes: determining the first space-frequency joint vector set, the first time-frequency domain vector set, the first space domain vector set, and the first weighting coefficient based on the first indication information, the sixth indication information, the second indication information, and the fourth indication information. A third matrix is ​​determined based on the first weighting coefficient and the first space-frequency joint vector set, wherein the third matrix is ​​obtained based on vector sampling of the fourth matrix, the fourth matrix is ​​the sixth matrix corresponding to the transmission moment of the second CSI-RS in the N sixth matrices, the N sixth matrices correspond one-to-one to the N first moments, the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix corresponds to the first antenna port set and the first frequency domain unit set. N sixth matrices are determined based on the third matrix, the first time-frequency domain vector set, the first space domain vector set, the first information, and the second information, wherein the first information is used to indicate the second antenna port set in the first antenna port set, and the second information is used to indicate the second frequency domain unit in the first frequency domain unit.

[0094] In combination with the fourth aspect, in a feasible implementation, the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same frequency domain unit set. The method also includes: determining the first space-frequency joint vector set, the first time-frequency domain vector set, the first space domain vector set, and the first weighting coefficient based on the first indication information, the sixth indication information, the second indication information, and the fourth indication information. Determine the fourth matrix based on the first weighting coefficient and the first space-frequency joint vector set, wherein the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix and the second CSI-RS correspond to the same antenna port set and frequency domain unit set. Determine N sixth matrices corresponding to N first moments based on the fourth matrix, the first time-frequency domain vector set, the first space domain vector set, the first information, and the second information, wherein the first information is used to indicate the second antenna port set in the first antenna port set, and the second information is used to indicate the second frequency domain unit in the first frequency domain unit.

[0095] In combination with the fourth aspect, in a feasible implementation, when the second matrix is ​​obtained by vector sampling of the first matrix based on the first information and / or the second information, the first information and / or the second information is provided by a network device.

[0096] In conjunction with the fourth aspect, in a feasible implementation, the transmission time of the second CSI-RS is indicated by the third information in the N first moments. That is, the third information can be used to indicate the transmission time of the second CSI-RS from the N first moments.

[0097] In conjunction with the fourth aspect, in a feasible implementation, the parameter N may be indicated by fourth information. Optionally, the fourth information is provided by a network device.

[0098] In a fifth aspect, the present application provides a communications device, comprising a transceiver unit and a processing unit. The transceiver unit is configured to receive a first channel state information reference signal (CSI-RS) from a network device. The processing unit is configured to generate first channel state information (CSI), wherein the first CSI includes first indication information of a first joint space-frequency vector set and at least one of second indication information of a first spatial vector set and third indication information of a first frequency vector set. The first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling of a first matrix, the first spatial vector set and the first frequency vector set are determined based on the first matrix, and the first matrix is ​​determined based on the first CSI-RS. The transceiver unit is further configured to transmit the first CSI to the network device. The transceiver unit is further configured to receive a second CSI-RS from the network device. The processing unit is further configured to generate second CSI, wherein the second CSI includes fourth indication information corresponding to a first weighting coefficient, wherein the first weighting coefficient is determined based on the first joint space-frequency vector set and the second CSI-RS. The transceiver unit is further configured to transmit the second CSI to the network device.

[0099] It should be understood that the transceiver unit and the processing unit in the communication device can also be used to implement other functions or method steps implemented in the CSI reporting method provided by the above-mentioned first aspect or any possible implementation method of the first aspect. For the specific process, please refer to the corresponding content described in the above-mentioned first aspect or any possible implementation method of the first aspect, and will not be repeated here.

[0100] In a sixth aspect, the present application provides a communication device, comprising a transceiver unit and a processing unit. The processing unit is configured to generate and trigger the transceiver unit to send a first channel state information reference signal (CSI-RS) to a terminal device. The transceiver unit is further configured to receive first channel state information (CSI) from the terminal device, wherein the first CSI includes first indication information of a first space-frequency joint vector set, and at least one of second indication information of a first spatial domain vector set and third indication information of a first frequency domain vector set, the first space-frequency joint vector set is determined based on a second matrix obtained by vector sampling of a first matrix, the first spatial domain vector set and the first frequency domain vector set are determined based on the first matrix, and the first matrix is ​​determined based on the first CSI-RS. The processing unit is further configured to generate and trigger the transceiver unit to send a second CSI-RS to the terminal device. The transceiver unit is further configured to receive second CSI from the terminal device, wherein the second CSI includes fourth indication information corresponding to a first weighting coefficient, and the first weighting coefficient is determined based on the first space-frequency joint vector set and the second CSI-RS.

[0101] It should be understood that the transceiver unit and the processing unit in the communication device can also be used to implement other functions or method steps implemented in the CSI reporting method provided by the above-mentioned second aspect or any possible implementation of the second aspect. For the specific process, please refer to the corresponding content described in the above-mentioned second aspect or any possible implementation of the second aspect, and will not be repeated here.

[0102] In a seventh aspect, the present application provides a communication device comprising a transceiver unit and a processing unit. The transceiver unit is configured to receive a target first channel state information reference signal (CSI-RS) from a network device. The processing unit is configured to generate a first CSI. The first CSI includes first indication information of a first joint space-frequency vector set. The first CSI also includes at least one of the following: fifth indication information of a first space-time domain vector set, sixth indication information of a first time-frequency domain vector set, third indication information of a first frequency-domain vector set, and second indication information of the first space-domain vector set. The first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling of the first matrix, the first matrix is ​​determined based on the target first CSI-RS, and the first space-domain vector set and the first frequency-domain vector set are determined based on the first matrix. The first space-time domain vector set and / or the first time-frequency domain vector set are determined based on at least two first statistical information matrices. Any first statistical information matrix J of the at least two first statistical information matrices is determined based on N first CSI-RSs continuously received by the terminal device. N is a positive integer greater than or equal to 2. The transceiver unit is configured to send the first CSI to the network device. The transceiver unit is further configured to receive a second CSI-RS from the network device. The processing unit is further configured to generate the second CSI. The transceiver unit is further configured to send the second CSI to the network device. The second CSI includes fourth indication information corresponding to a first weighting coefficient, where the first weighting coefficient is determined based on the first space-frequency joint vector set and the second CSI-RS.

[0103] It should be understood that the transceiver unit and the processing unit in the communication device can also be used to implement other functions or method steps implemented in the CSI reporting method provided by the third aspect or any possible implementation of the third aspect. For the specific process, please refer to the corresponding content described in the third aspect or any possible implementation of the third aspect, and no further details will be given here.

[0104] In an eighth aspect, the present application provides a communication device, comprising a transceiver unit and a processing unit. The processing unit is configured to generate and trigger the transceiver unit to send a target first channel state information reference signal (CSI-RS) to a terminal device. The transceiver unit is further configured to receive first channel state information (CSI) from the terminal device. The first CSI includes first indication information of a first joint space-frequency vector set, and at least one of the following: fifth indication information of a first time-space domain vector set, sixth indication information of a first time-frequency domain vector set, third indication information of a first frequency domain vector set, and second indication information of the first space domain vector set. The first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling of the first matrix, the first matrix is ​​determined based on the target first CSI-RS, the first space domain vector set and the first frequency domain vector set are determined based on the first matrix, the first time-space domain vector set and / or the first time-frequency domain vector set are determined based on at least two first statistical information matrices, and any first statistical information matrix J of the at least two first statistical information matrices is determined based on N first CSI-RSs continuously received by the terminal device, where N is a positive integer greater than or equal to 2. The processing unit is further configured to generate and trigger the transceiver unit to send a second CSI-RS to the terminal device. The transceiver unit is further configured to receive second CSI from the terminal device, wherein the second CSI includes fourth indication information corresponding to a first weighting coefficient, and the first weighting coefficient is determined based on the first space-frequency joint vector set and the second CSI-RS.

[0105] It should be understood that the transceiver unit and the processing unit in the communication device can also be used to implement other functions or method steps implemented in the CSI reporting method provided by the above-mentioned fourth aspect or any possible implementation of the fourth aspect. For the specific process, please refer to the corresponding content described in the above-mentioned fourth aspect or any possible implementation of the fourth aspect, and will not be repeated here.

[0106] In the ninth aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, cause the computer to execute the method of the first aspect or any possible implementation of the first aspect, or to execute the method of the second aspect or any possible implementation of the second aspect.

[0107] In the tenth aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, cause the computer to execute the method of the third aspect or any possible implementation of the third aspect, or to execute the method of the fourth aspect or any possible implementation of the fourth aspect.

[0108] In the eleventh aspect, the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed, it is used to execute the method in the first aspect or any possible implementation of the first aspect, or to execute the method in the second aspect or any possible implementation of the second aspect.

[0109] In the twelfth aspect, the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed, it is used to execute the method in the third aspect or any possible implementation of the third aspect, or to execute the method in the fourth aspect or any possible implementation of the fourth aspect.

[0110] In a thirteenth aspect, the present application provides a communication device, at least one processor, and a memory. The memory is configured to store a computer program. The processor is configured to execute the computer program stored in the memory, so that the communication device performs the method of the first aspect or any possible implementation of the first aspect, or performs the method of the second aspect or any possible implementation of the second aspect.

[0111] In a fourteenth aspect, the present application provides a communication device, at least one processor, and a memory. The memory is configured to store a computer program. The processor is configured to execute the computer program stored in the memory, so that the communication device performs the method of the third aspect or any possible implementation of the third aspect, or performs the method of the fourth aspect or any possible implementation of the fourth aspect.

[0112] In the fifteenth aspect, an embodiment of the present application provides a chip, comprising a processor and an interface, wherein the interface is used to interact with information or data, and the processing circuit is used to run instructions so that a device on which the chip is installed executes the method in the first aspect or any possible implementation of the first aspect, or executes the method in the second aspect or any possible implementation of the second aspect.

[0113] In the sixteenth aspect, an embodiment of the present application provides a chip, comprising a processor and an interface, wherein the interface is used to interact with information or data, and the processing circuit is used to run instructions so that a device on which the chip is installed executes the method in the third aspect or any possible implementation of the third aspect, or executes the method in the fourth aspect or any possible implementation of the fourth aspect.

[0114] In the seventeenth aspect, the present application provides a chip system, which includes a processor for supporting the device on which the chip system is installed to implement the method in the first aspect or any possible implementation of the first aspect, or to implement the method in the second aspect or any possible implementation of the second aspect. For example, the data and / or information involved in the above method is generated or processed. In one possible design, the chip system also includes a memory, which is used to store program instructions and data necessary for the data sending device. The chip system can be composed of chips, or it can include chips and other discrete devices.

[0115] In the eighteenth aspect, the present application provides a chip system, which includes a processor for supporting the device in which the chip system is installed to implement the method in the third aspect or any possible implementation of the third aspect, or to implement the method in the fourth aspect or any possible implementation of the fourth aspect. For example, the data and / or information involved in the above method is generated or processed. In one possible design, the chip system also includes a memory, which is used to store program instructions and data necessary for the data sending device. The chip system can be composed of chips, or it can include chips and other discrete devices.

[0116] In the nineteenth aspect, the present application provides a communication system, which includes a terminal device having functions for implementing the methods and various possible designs of the above-mentioned first aspect and a network device having functions for implementing the methods and various possible designs of the above-mentioned second aspect.

[0117] In the twentieth aspect, the present application provides a communication system, which includes a terminal device having functions for implementing the methods and various possible designs of the above-mentioned third aspect and a network device having functions for implementing the methods and various possible designs of the above-mentioned fourth aspect.

[0118] By adopting the embodiments of the present application, the complexity and overhead of CSI reporting can be reduced while ensuring the accuracy of CSI reporting, thereby ensuring the rational use of communication resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0119] Figure 1 This is a schematic diagram of the structure of a communication system provided by this application;

[0120] Figure 2 This is a flow chart of a channel state information (CSI) reporting method provided by this application;

[0121] Figure 3 This is another flow chart of a channel state information (CSI) reporting method provided by this application;

[0122] Figure 4This is another flow chart of a channel state information (CSI) reporting method provided by this application;

[0123] Figure 5 This is another flow chart of a channel state information (CSI) reporting method provided by this application;

[0124] Figure 6 This is a schematic diagram of the structure of a communication device provided by this application;

[0125] Figure 7 This is a structural diagram of another communication device provided by this application;

[0126] Figure 8 This is a structural diagram of another communication device provided by this application. DETAILED DESCRIPTION

[0127] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings provided in the embodiments of the present application.

[0128] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0129] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship; in the formula of this application, the character " / " indicates that the previous and next associated objects are in a "division" relationship. "Including at least one of A, B and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B and C.

[0130] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

[0131] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: Long Term Evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) communication system, 5G system or new radio (NR). In addition, it can also be applied to subsequent evolution systems, such as the sixth-generation 6G communication system and even the more advanced seventh-generation 7G communication system.

[0132] The network device in the embodiment of the present application can be a device for communicating with a terminal device, can be a base station, or an access point, or a network device, or can refer to a device in an access network that communicates with a wireless terminal through one or more sectors on the air interface. The network device can be used to convert received air frames into and out of Internet Protocol (IP) packets, and act as a router between the wireless terminal and the rest of the access network, where the rest of the access network may include an IP network. The network device can also coordinate the attribute management of the air interface. For example, the network device can be an evolved NodeB (eNB or eNodeB) in an LTE system, or a wireless controller in a cloud radio access network (CRAN) scenario, or the access device can be a relay station, an access point, an in-vehicle device, a wearable device, an access device in a 5G network, or a network device in a future evolved PLMN network, etc. It can be an access point (AP) in a WLAN, or a 5G wireless base station (i.e., gNodeB, which can be abbreviated as gNB) in an NR system, and the embodiment of the present application is not limited thereto.

[0133] It should be noted that for the 5G system, there may be one or more transmission reception points (TRP) under one base station, and multiple TRPs belong to the same cell, wherein each TRP and terminal device can use the channel state information reporting method of the embodiment of the present application. In another scenario, the network equipment can also be divided into a central unit (CU) and a distributed unit (DU). Under one CU, there may be multiple DUs, wherein each DU and terminal device can use the channel state information reporting method of the embodiment of the present application. The difference between the CU-DU separation scenario and the multi-TRP scenario is that the TRP is only a radio frequency unit or an antenna device, while the protocol stack function can be implemented in the DU, for example, the physical layer function can be implemented in the DU.

[0134] In addition, in the embodiments of the present application, the network device may be a device in a radio access network (RAN), or in other words, a RAN node that connects a terminal device to a wireless network. For example, as an example and not a limitation, the network device may include: gNB, TRP, evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved Node B, or home Node B, HNB), base band unit (BBU), or wireless fidelity (Wifi) access point (AP).

[0135] The network equipment provides services for the cell, and the terminal device communicates with the network equipment through the transmission resources used by the cell (for example, frequency domain resources, or spectrum resources). The cell can be the cell corresponding to the network equipment (for example, a base station). The cell can belong to a macro base station or a base station corresponding to a small cell. The small cells here can include: metro cells, micro cells, pico cells, femto cells, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services.

[0136] The terminal device in the embodiments of the present application may also be referred to as: user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent or user device, etc.

[0137] The terminal device may be a device that provides voice / data connectivity to users, such as a handheld device or vehicle-mounted device with wireless connection function. At present, some examples of terminals are: mobile phones, tablet computers, laptop computers, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to wireless modems, vehicle-mounted devices, wearable devices, terminal devices in 5G networks or future evolved public land mobile communication networks (PLMNs). The terminal equipment in the network (PLMN), etc., is not limited to this in the embodiments of the present application.

[0138] As an example and not a limitation, in the embodiments of the present application, wearable devices may also be referred to as wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, etc. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are fully functional, large in size, and can achieve complete or partial functions without relying on smartphones, such as smart watches or smart glasses, as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0139] In addition, in the embodiment of the present application, the terminal device can also be a terminal device in the Internet of Things (IoT) system. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network of human-machine interconnection and object-to-object interconnection.

[0140] In the embodiment of the present application, the terminal device may further include a relay. Alternatively, it can be understood that anything that can communicate data with a base station can be considered a terminal device.

[0141] See Figure 1 , Figure 1 This application provides a structural diagram of a communication system. Figure 1The system includes a network device 110, a terminal device 120, a terminal device 130, a terminal device 140, a terminal device 150, a terminal device 160, and a terminal device 170. The network device 110 operates in an evolved universal mobile telecommunications system terrestrial radio access (E-UTRA) system, or in an NR system, or in a next generation communication system or other communication system. The network device 110 and the terminal devices 120 to 170 can communicate through a Uu interface, and the network device 110 and the terminal devices 120 to 170 form a communication system. In this communication system, the terminal devices 120 to 170 can send uplink data to the network device 110, the network device 110 needs to receive the uplink data sent by the terminal devices 120 to 170, and the network device 110 can send downlink data to the terminal devices 120 to 170. In addition, the terminal devices 150 to 170 can also form a communication system. In this communication system, the network device may send downlink information to the terminal device 150 , and the terminal device 150 may also send downlink information to the terminal device 160 and the terminal device 170 .

[0142] In this application, one network device can serve multiple terminal devices. Figure 1 Just take some of the terminal devices as examples.

[0143] Figure 1 The network device in the embodiment may be a base station. The network device corresponds to different devices in different systems. For example, in a 4G system, it may correspond to an eNB, and in a 5G system, it may correspond to a network device in 5G, such as a gNB. The technical solution provided by this application may also be applied to future mobile communication systems. Figure 1 The network devices in the figure can also correspond to the network devices in future mobile communication systems. Figure 1 Taking the network device being a base station as an example, in fact, referring to the introduction in the previous article, the network device can also be a road side unit (RSU) and other equipment.

[0144] It should be understood that Figure 1 The communication system shown may also include more network nodes, such as other terminal devices or network devices. Figure 1 The network devices or terminal devices included in the communication system shown can be the various forms of network devices or terminal devices mentioned above. The embodiments of the present application are not shown one by one in the figures.

[0145] 5G communication systems have higher requirements for system capacity and spectrum efficiency. The application of Massive MIMO technology plays a crucial role in improving the system's spectrum efficiency. When using MIMO technology, network equipment must precode data before sending it to terminal devices. The method for precoding depends on the CSI (Current Signal Indicator) fed back by the user equipment to the network equipment.

[0146] In a TDD system, because the uplink and downlink channels use the same frequency band, they are reciprocal. Network equipment can use this channel reciprocity to obtain the CSI of the downlink channel through the uplink channel and then perform precoding. In an FDD system, however, because the interval between the uplink and downlink frequency bands is greater than the bandwidth, there is no complete reciprocity between the uplink and downlink channels. In an FDD system, the terminal device needs to feedback the CSI of the downlink channel to the network device. The existing method for feedbacking the CSI of the precoding matrix may include the following steps:

[0147] S1. The network device sends channel measurement configuration information to the terminal device. The channel measurement configuration information is used to configure the time and behavior of the terminal device to perform channel measurement.

[0148] S2: The network device sends a channel measurement pilot to the terminal device for channel measurement. Here, the pilot can be understood as a reference signal (RS), such as a channel state information reference signal (CSI-RS).

[0149] S3: The terminal device performs measurement based on the channel measurement pilot sent by the network device, calculates the final CSI feedback amount based on the measurement result, and feeds back the CSI to the network device.

[0150] S4: The network device sends data based on the CSI fed back by the terminal device.

[0151] CSI may include parameters such as PMI, channel rank indicator (RI), and channel quality indicator (CQI). For example, the network device may determine the precoding of data transmitted to the terminal device based on the PMI fed back by the terminal device; the network device may determine the number of streams for data transmission to the terminal device based on the RI fed back by the terminal device; and the network device may determine the modulation order and channel coding code rate for data transmission to the terminal device based on the CQI fed back by the terminal device.

[0152] In actual implementation, PMI is determined and reported based on a set of codebooks to indicate the precoding matrix, and the network device recovers the precoding matrix based on the PMI and the codebook. The precoding matrix can be a precoding matrix determined by the network device based on the channel matrix of each frequency domain unit. For example, the precoding matrix can be obtained by performing singular value decomposition (SVD) on the channel matrix or the covariance matrix of the channel matrix, or by performing eigenvalue decomposition (EVD) on the covariance matrix of the channel matrix. The precoding matrix contains the channel information of the transmitting end of the network device. The design of the FDD CSI codebook is a basic and important issue in the 5G communication system.

[0153] The 3GPP R15 Type II codebook uses spatial (angle domain) compression. This exploits the angular sparsity of the channel, where multipath signals have strong energy in certain angular directions and weak energy in other directions. Spatial discrete Fourier transform (DFT) basis vectors are used to represent these angular directions with strong energy, and the precoding matrix is ​​represented by a linear combination of several spatial DFT basis vectors. The 3GPP R16 enhanced Type II codebook proposes a dual-domain compression approach. Building on the R15 codebook, it leverages the frequency domain correlation of the amplitude and phase coefficients of different subbands to add frequency domain (delay domain) compression. Channel information is compressed and fed back in both the spatial and frequency domains, and the precoding matrix is ​​approximated by the weighted sum of space-frequency component matrices. This space-frequency component matrix is ​​constructed from one or more spatial basis vectors compressed in the spatial domain and one or more frequency basis vectors compressed in the frequency domain.

[0154] To fully leverage the channel sparsity in both the spatial and frequency domains and improve the accuracy of PMI feedback, a statistical characteristic subspace codebook can be used for feedback. This codebook uses statistical characteristic subspace basis and corresponding linear combination coefficients to represent the downlink channel or precoding matrix. This codebook can be similar to the R16 enhanced type II codebook, where both the spatial and frequency domains are represented using a set of DFT basis through a bilinear combination. Furthermore, the codebook can also be a joint spatial and frequency domain, represented using a linear combination of a set of joint spatial and frequency characteristic subspace basis. A statistical characteristic subspace basis is an eigenvector or set of vectors that can be used to represent the statistical variation of the channel in the spatial, frequency, or joint spatial and frequency domains. It is typically obtained by performing eigenvalue decomposition on the channel's statistical covariance matrix. The joint spatial and frequency domain is a combination of the spatial and frequency domains. Generally speaking, signals propagate along multiple paths, leaving the transmitter at different angles and arriving at the receiver at different angles after varying delays. The spatial domain primarily describes the angular and directional characteristics of the channel, while the frequency domain primarily describes the delay distribution of the channel. Both are considered from a single dimension. The joint space-frequency domain considers the combination of space domain and frequency domain, mainly describing the angular direction and delay distribution characteristics of multipath.

[0155] In the examples of the present application, the statistical characteristic subspace basis used to represent the statistical variation law of the channel in the spatial domain can also be understood as a spatial basis, a set of spatial basis vectors, or a set of spatial vectors. The statistical characteristic subspace basis used to represent the statistical variation law of the channel in the frequency domain can also be called a frequency domain basis, a set of frequency domain basis vectors, or a set of frequency domain vectors. The statistical characteristic subspace basis used to represent the statistical variation law of the channel in the joint spatial-frequency domain can also be called a joint spatial-frequency basis, a joint spatial-frequency basis vector set, or a joint spatial-frequency vector set. In addition, in the embodiments of the present application, a vector set is equivalent to a matrix, and each column or row in the matrix is ​​a vector in the vector set. For example, the set of spatial-frequency joint vectors involved later is equivalent to a joint spatial-frequency matrix, and each column thereof is a joint spatial-frequency vector. For another example, the set of spatial vectors involved later is equivalent to a spatial matrix, and each column thereof is a spatial-frequency vector.

[0156] In practical applications, although the use of a joint space-frequency basis can ensure the accuracy of CSI reporting, the complexity of the joint space-frequency basis and the corresponding large overhead of the basis indication information lead to high complexity and high overhead of CSI reporting, which is not conducive to the efficient use of communication resources.

[0157] Therefore, the technical problem to be solved by this application is: how to reduce the overhead and complexity of CSI reporting while ensuring the accuracy of CSI reporting.

[0158] Example 1

[0159] To address the above technical issues, the present application provides a channel state information (CSI) reporting method. In this method, a terminal device reports a first set of joint space-frequency vectors and at least one of a first set of spatial domain vectors and a first set of frequency domain vectors to a network device via a first CSI, and reports a first weighting coefficient corresponding to the first set of joint space-frequency vectors via a second CSI. On one hand, because the first set of joint space-frequency vectors is determined based on a second matrix obtained by vector sampling from a first matrix, compared to the prior art method of directly obtaining a set of joint space-frequency vectors based on the first matrix, the reported first set of joint space-frequency vectors in the present application scheme has lower complexity, and the corresponding indication information occupies less overhead. Similarly, the corresponding weighting coefficient occupies less overhead. Therefore, the CSI reporting method provided in the present application has low complexity and low overhead. On the other hand, because the first CSI reports the first set of joint space-frequency vectors and at least one of the first set of spatial domain vectors and the first set of frequency domain vectors, the scheme provided in the present application can still ensure the accuracy of CSI reporting. Therefore, the CSI reporting method provided in the present application can reduce the complexity and overhead of CSI reporting while ensuring the accuracy of CSI reporting. Therefore, by adopting the technical solution provided in this application, the problem of high complexity and high overhead of CSI reporting in the existing technology can be solved, which is conducive to the rational use of communication resources.

[0160] See Figure 2 , Figure 2 This is a flow chart of a channel state information CSI reporting method provided by this application. It should be understood that this embodiment will use network equipment and terminal equipment as a method to illustrate the channel state information CSI reporting method provided by this application. This is an example and not a limitation. The execution subject of the channel state information CSI reporting method provided by this application can also be a chip, chip system, or processor applied to the terminal equipment and network equipment, and this application does not impose specific restrictions on this. Figure 2 As shown, the channel state information CSI reporting method provided in this application may include the following steps:

[0161] S210: The network device sends a first CSI-RS to the terminal device. Correspondingly, the terminal device receives the first CSI-RS.

[0162] In some feasible implementations, the network device can generate a first CSI-RS and send the first CSI-RS to the terminal device on the corresponding time-frequency resources. Accordingly, the terminal device receives the first CSI-RS from the network device on the time-frequency resources. Among them, the first CSI-RS is mainly used for the terminal device to feedback the first CSI. It should be understood that in actual implementation, the network device will send corresponding CSI reporting configuration information (such as CSI-ReportConfig) to the terminal device, and the terminal device can perform CSI reporting based on the CSI reporting configuration information to send the above-mentioned first CSI. This CSI reporting configuration information contains the configuration information of the first CSI-RS. The time-frequency resource for transmitting the first CSI-RS is indicated by the configuration information of the first CSI-RS.

[0163] S211: The terminal device determines first CSI. The first CSI includes first indication information of a first joint space-frequency vector set, and at least one of second indication information of a first space-domain vector set and third indication information of a first frequency-domain vector set.

[0164] In some feasible implementations, after receiving the first CSI-RS, the terminal device may determine the first CSI based on the first CSI-RS. The first CSI may include first indication information of the first space-frequency joint vector set. The first matrix of the first space-frequency joint vector set is determined by a second matrix obtained by vector sampling. The first matrix is ​​determined based on the first CSI-RS. For example, the first matrix is ​​determined based on the measurement result of the first CSI-RS. Furthermore, the first CSI also includes at least one of the second indication information of the first space domain vector set and the third indication information of the first frequency domain vector set. Both the first space domain vector set and the first frequency domain vector set can be determined based on the first matrix. It can also be understood that the first CSI includes the first indication information, and the first CSI also includes at least one of the second indication information and the third indication information. The first indication information is used to indicate the first space-frequency joint vector set, the second indication information is used to indicate the first space domain vector set, and the third indication information is used to indicate the first frequency domain vector set.

[0165] It should be noted that, in actual implementation, the above-mentioned first matrix can be the channel matrix corresponding to a certain terminal antenna port or the precoding matrix corresponding to a certain stream / layer (stream / layer) determined by the terminal device based on the measurement result of the above-mentioned first CSI-RS. It should be understood that the terminal device usually reports the channel matrices corresponding to multiple terminal antenna ports together. Since the method provided in this application is similar for the channel matrix corresponding to each terminal antenna port, the embodiment of this application will take the case of reporting the channel matrix corresponding to a certain terminal antenna port as an example. In addition, in the case where the first matrix is ​​a precoding matrix or a channel matrix, the first weighting coefficient mentioned later can also be used by the network device to determine the channel matrix or precoding matrix reported by the terminal device.

[0166] It should also be understood that in the solution provided in the present application, the vector sampling of the matrix mainly includes vector sampling of the spatial domain dimension (hereinafter referred to as spatial domain sampling), vector sampling of the frequency domain dimension (hereinafter referred to as frequency domain sampling), and vector sampling of both the spatial and frequency domain dimensions (hereinafter referred to as spatial-frequency domain sampling). In this embodiment, the dimensions of the matrix generated by the terminal device based on the measurement results of the CSI-RS mainly include spatial domain dimensions and frequency domain dimensions. The so-called spatial domain dimension refers to the antenna port set composed of the antenna ports on the network device side corresponding to the CSI-RS. The so-called frequency domain dimension refers to the frequency domain unit set composed of the frequency domain units occupied by the CSI-RS.

[0167] In addition, in an embodiment of the present application, the number of rows of the matrix (which can also be understood as the number of row vectors contained in the matrix) can be equal to the number of antenna ports contained in the antenna port set corresponding to the matrix, and the number of columns of the matrix (which can also be understood as the number of column vectors contained in the matrix) can be equal to the number of frequency domain units contained in the frequency domain unit set corresponding to the matrix. Of course, it is also possible that the number of rows of the matrix is ​​equal to the number of frequency domain units contained in the frequency domain unit set, and the number of columns of the matrix is ​​equal to the number of antenna ports contained in the antenna port set. In order to avoid redundancy, this application will uniformly illustrate the example of the number of antenna ports contained in the antenna port set corresponding to the matrix being equal to the number of rows of the matrix, and the number of frequency domain units contained in the frequency domain unit set corresponding to the matrix being equal to the number of columns of the matrix.

[0168] Taking the first matrix as an example, the first matrix may correspond to the first antenna port set and the first frequency domain unit set. The first antenna port set includes multiple antenna ports corresponding to the first CSI-RS, and the first frequency domain unit set includes multiple frequency domain units occupied by the first CSI-RS. Furthermore, the number of rows of the first matrix (which can also be understood as the number of row vectors contained in the first matrix) may be equal to the number of antenna ports contained in the first antenna port set (for the sake of distinction, the first antenna port will be used to represent the expression in the following text), and the number of columns of the first matrix (which can also be understood as the number of column vectors contained in the first matrix) may be equal to the number of frequency domain units contained in the first frequency domain unit set (for the sake of distinction, the first antenna port will be used to represent the expression in the following text). For the sake of convenience, in this embodiment, the first antenna port set may specifically include m antenna ports, namely, antenna port s1, antenna port s2, antenna port s3 to antenna port sm. The first frequency domain unit set may include p frequency domain units, namely, frequency domain unit f1, frequency domain unit f2 to frequency domain unit fp. Wherein, m and p are positive integers greater than or equal to 2.

[0169] Since there are multiple implementation methods for the above-mentioned first CSI, for ease of understanding, the following will describe the process of the terminal device determining the first CSI in multiple scenarios.

[0170] Scenario 1.1.1:

[0171] In this scenario, the first CSI may include first indication information and second indication information. In this case, the first matrix may correspond to the first antenna port set and the first frequency domain element set, while the second matrix may correspond to the second antenna port set and the first frequency domain element set. Furthermore, the second antenna port set is a subset of the first antenna port set. It can also be understood that the second matrix is ​​obtained by vector sampling of the spatial dimension of the first matrix.

[0172] In a specific implementation, after receiving the first CSI-RS, the terminal device can obtain the measurement result of the first CSI-RS and determine the first matrix based on the measurement result of the first CSI-RS. Here, the first matrix can be a channel matrix corresponding to a terminal antenna port or a precoding matrix corresponding to a stream / layer determined by the terminal device based on the measurement result of the first CSI-RS.

[0173] Furthermore, the terminal device may perform vector sampling on the first matrix to obtain the second matrix.

[0174] In an optional implementation, the second matrix may be obtained by the terminal device by performing vector sampling on the first matrix based on the first information. The first information is used to indicate the second antenna port set from the first antenna port set. That is, the terminal device may determine the second antenna port set from the first antenna port set based on the first information, and then perform vector sampling of the spatial dimension of the first matrix based on the second antenna port set to obtain the second matrix.

[0175] In an optional implementation, the first information may include the antenna port interval number and the identifier of the starting antenna port. It should be understood that the identifier of the starting antenna port may also be the sequence number or index of the starting antenna port, which is not limited in this application. The second antenna port set can be determined by the terminal device in the first antenna port set according to the starting antenna port and the antenna port interval number.

[0176] For example, assuming that the starting antenna port is identified as antenna port 1 and the antenna port interval is 1. The terminal device may start from antenna port 1 and select every other antenna port, thereby selecting antenna port 1, antenna port 3, antenna port 5, antenna port 7, and antenna port m-1 (here assuming that m is an even number) from the first antenna port set, and determining a second antenna port set including these selected antenna ports.

[0177] In another optional implementation, the first information may include the number of antenna port intervals in the first dimension, the number of antenna port intervals in the second dimension, and the identifier of the starting antenna port. Similarly, the identifier of the starting antenna port may also be the serial number or index of the starting antenna port, which is not limited in this application. The second antenna port set can be determined by the terminal device starting from the starting antenna port in the first antenna port set, according to the first dimension antenna port interval number in the first dimension and the second dimension antenna port interval number in the second dimension.

[0178] For example, assume that the starting antenna port is identified as antenna port 1, and the first-dimension antenna port spacing number and the second-dimension antenna port spacing number are both 1. Assume that there are 32 first antenna ports in the above-mentioned first antenna port set, namely, first antenna port 1, first antenna port 2, through first antenna port 32, where first antenna port 1 through first antenna port 16 correspond to the first polarization direction, and first antenna port 17 through first antenna port 32 correspond to the second polarization direction. These 32 first antenna ports form an array of 2 rows and 8 columns, with the row direction being the first dimension of the array and the column direction being the second dimension of the array. Each element position in the array has two antenna ports corresponding to different polarization directions. Furthermore, the first row of the array sequentially comprises first antenna port 1 through first antenna port 8 in the first polarization direction and first antenna ports 17 through 24 in the second polarization direction, and the second row sequentially comprises first antenna ports 9 through 16 in the first polarization direction and first antenna port 25 through first antenna port 32 in the second polarization direction. After obtaining the antenna port spacing number in the first dimension, the antenna port spacing number in the second dimension, and the identifier of the starting antenna port, the terminal device may select, starting with the first antenna port 1, the first antenna ports of two polarization directions in the first row and the first column, the third column, the fifth column, and the seventh column in the array, thereby selecting eight first antenna ports: first antenna port 1, first antenna port 3, first antenna port 5, first antenna port 7, first antenna port 17, first antenna port 19, first antenna port 21, and first antenna port 23. The terminal device may then form the second antenna port set based on these eight selected first antenna ports.

[0179] It should be noted that the above two methods are applicable to the case of performing uniform vector sampling of the spatial dimension of the first matrix.

[0180] In another optional implementation, the first information may include a first bitmap (i.e., a bitmap). Each bit in the first bitmap corresponds one-to-one to each first antenna port in the first antenna port set. A second antenna port in the second antenna port set is a target first antenna port in the first antenna port set. In addition, the bits corresponding to the target first antenna ports in the first antenna port set in the first bitmap adopt a first value, and the bits corresponding to the first bitmap of the other first antenna ports in the first antenna port set except the target first antenna ports adopt a second value. Here, the first value and the second value are different. That is, the terminal device can select the target first antenna ports corresponding to the bits in the first bitmap whose value is the first value, and form the second antenna port set based on the selected target first antenna ports.

[0181] For example, it is assumed that the first bitmap includes bit 1, bit 2 to bit m corresponding to antenna port 1 to antenna port m, respectively. Among them, the values ​​of bit 1, bit 4, bit 6, bit 9, and bit 11 are all 1, and the values ​​of the remaining bits are all 0. When the above-mentioned first value is 1, the terminal device can select antenna port 1, antenna port 4, antenna port 6, and antenna port 9 from the first antenna port set based on the first bitmap, and form a second antenna port set based on these antenna ports.

[0182] It should be noted that this method is applicable to the case of performing non-uniform vector sampling of the spatial dimension of the first matrix.

[0183] It should be noted that, in some optional implementations, the above-mentioned first information can be configured by a network device. In the case where the first information is configured by the network device and the first information includes the number of antenna port intervals and the identifier of the starting antenna port, the number of antenna port intervals and the identifier of the starting antenna port can be configured by the same signaling, or they can be configured by different signaling. For example, the network device can configure the above-mentioned number of antenna port intervals for the terminal device through radio resource control (RRC) signaling, and configure the above-mentioned identifier of the starting antenna port for the terminal device through downlink control information (DCI) signaling. It should be understood that the network device can also use other methods to configure the above-mentioned first information for the terminal device, and this application does not impose specific restrictions on this. In some other optional implementations, the first information can also be pre-defined by the communication protocol between the network device and the terminal device.

[0184] After determining the second antenna port set, the terminal device can perform vector sampling on the first matrix based on the second antenna port set to obtain a second matrix. For example, the terminal device can determine row vectors in the first matrix corresponding to multiple second antenna ports included in the second antenna port set, and compose the second matrix based on these determined row vectors, thereby completing vector sampling of the spatial dimension of the first matrix.

[0185] Furthermore, after acquiring the second matrix, the terminal device may determine the first joint space-frequency vector set according to the second matrix.

[0186] Exemplarily, the terminal device may first calculate the statistical information matrix corresponding to the second matrix. It should be understood that the number of rows of the statistical information matrix is ​​equal to the product ms*p of the number of second antenna ports included in the second antenna port set (here it is assumed to be ms, it should be understood that ms should be less than m) and the number of first frequency domain units p included in the above-mentioned first frequency domain unit set, and the number of columns of the statistical information matrix is ​​also equal to the product ms*p. After obtaining the statistical information matrix corresponding to the second matrix, the terminal device may perform eigenvector extraction on the statistical information matrix to obtain the above-mentioned first space-frequency joint vector set. Specifically, the terminal device may first determine the P1 largest eigenvalues ​​based on the statistical information matrix. Here, P1 is a positive integer greater than or equal to 1. It should be understood that P1 may be configured by the network device or specified in the communication protocol between the network device and the terminal device, and this application does not impose specific restrictions on this. Then, the terminal device may extract the eigenvectors corresponding to these P1 eigenvalues ​​and form the above-mentioned first space-frequency joint vector set.

[0187] Optionally, the statistical information matrix corresponding to the second matrix may be a space-frequency domain statistical covariance matrix obtained by transforming the second matrix.

[0188] Furthermore, after obtaining the above-mentioned first matrix, the terminal device can also determine the above-mentioned first spatial domain vector set based on the first matrix. Specifically, the terminal device can first calculate the spatial domain statistical covariance matrix corresponding to the first matrix based on the first matrix. Here, the number of rows and columns of the spatial domain statistical covariance matrix are both equal to m. Then, the terminal device can extract the eigenvectors of the spatial domain statistical covariance matrix corresponding to the first matrix to obtain the above-mentioned first spatial domain vector set. Specifically, the terminal device can first determine the P2 eigenvalues ​​with the largest values ​​based on the spatial domain statistical covariance matrix. Here, P2 is a positive integer greater than or equal to 1. It should be understood that P2 can be configured by the network device or specified in the communication protocol between the network device and the terminal device, and this application does not impose specific restrictions on this. Then, the terminal device can extract the eigenvectors corresponding to these P2 eigenvalues ​​and form the above-mentioned first spatial domain vector set.

[0189] Furthermore, after determining the above-mentioned first spatial joint vector set and the first spatial vector set, the terminal device can determine the first indication information corresponding to the first spatial-frequency joint vector set and the second indication information corresponding to the first spatial vector set, and then generate the first CSI containing the above-mentioned first indication information and the second indication information.

[0190] In some optional implementations, the first indication information includes first sub-indication information of a first common vector subset and second sub-indication information of a second weighting coefficient. Here, the first common vector subset and the second weighting coefficient may be used to determine a first set of joint space-frequency vectors. Furthermore, the first sub-indication information may be used to indicate the first common vector subset from the full set of first common vectors.

[0191] It should be explained that, in actual implementation, considering issues such as overhead, the first space-frequency joint vector set can be specifically indicated by a common vector set (i.e., the first common vector subset mentioned above) and a set of weighting coefficients (i.e., the second weighting coefficients mentioned above). The second weighting coefficients are the weighting coefficients obtained by projecting or mapping the first space-frequency joint vector set onto the first common vector subset. Therefore, the second weighting coefficients and the first common vector subset can be used by the network device to determine the above-mentioned first space-frequency joint vector set. It can also be understood that the first space-frequency joint vector set is equal to the product of the first common vector set and the second weighting coefficient.

[0192] It should also be noted that the first complete set of common vectors may specifically be composed of multiple vectors known to the network device and the terminal device, and the first sub-indication information may be the index of each common vector included in the first complete set of common vectors. The second sub-indication information may be the amplitude information and phase information of the second weighting coefficient.

[0193] Optionally, each common vector in the first set of common vectors may be obtained by using a two-dimensional discrete Fourier transform vector (also expressed as a 2D-DFT vector) and a DFT vector through a Kronecker product.

[0194] Similarly, the second indication information may include third sub-indication information of the second common vector subset and fourth sub-indication information of the third weighting coefficient. The second common vector subset and the third weighting coefficient may be used to determine the first spatial vector set. Furthermore, the third sub-indication information may be used to indicate the second common vector subset from the full set of second common vectors. Optionally, each common vector in the full set of second common vectors may be a 2D-DFT vector.

[0195] In the above implementation, when only the vector of the spatial dimension is extracted for the first matrix, the network device does not need to use the first frequency domain vector set when reconstructing the matrix, so the first CSI only needs to report the first space-frequency joint vector set and the first spatial domain set. This can also avoid the waste of communication resources caused by reporting an invalid first frequency domain vector set.

[0196] Scenario 1.1.2:

[0197] In this scenario, the first CSI may include the first indication information and the third indication information. In this case, the first matrix may correspond to the first antenna port set and the first frequency domain unit set, while the second matrix may correspond to the first antenna port set and the second frequency domain unit set. Furthermore, the second frequency domain unit set is a subset of the first frequency domain unit set. In other words, the second matrix is ​​obtained by the terminal device sampling the first matrix by vectors in the frequency domain dimension.

[0198] In a specific implementation, after receiving the first CSI-RS, the terminal device can obtain the measurement result of the first CSI-RS and determine the first matrix based on the measurement result of the first CSI-RS. Here, the first matrix can be a channel matrix corresponding to a terminal antenna port or a precoding matrix corresponding to a stream / layer determined by the terminal device based on the measurement result of the first CSI-RS.

[0199] Furthermore, the terminal device may perform vector sampling on the first matrix to obtain the second matrix.

[0200] In an optional implementation, the second matrix can be obtained by the terminal device by performing vector sampling on the first matrix based on the second information. The second information is primarily used to indicate the second set of frequency domain units from the first set of frequency domain units. That is, the terminal device can determine the second set of frequency domain units from the first set of frequency domain units based on the second information. Then, based on the second set of frequency domain units, the first matrix is ​​vector sampled in the frequency domain dimension to obtain the second matrix.

[0201] In an optional implementation, the second information may include the number of frequency domain unit intervals and the identifier of the starting frequency domain unit. It should be understood that the identifier of the starting frequency domain unit may also be the sequence number or index of the starting frequency domain unit, which is not limited in this application. The second frequency domain unit set can be determined by the terminal device in the first frequency domain unit set according to the starting frequency domain unit and the number of frequency domain unit intervals.

[0202] For example, assuming that the starting frequency domain unit is identified as frequency domain unit 1 and the number of frequency domain unit intervals is 2, the terminal device may start from frequency domain unit 1 and select every three frequency domain units, thereby selecting frequency domain unit 1, frequency domain unit 4, frequency domain unit 7, frequency domain unit 10, and other frequency domain units from the first frequency domain unit set, and determining a second frequency domain unit set that includes these selected frequency domain units.

[0203] It should be noted that this method is applicable to the case of performing uniform vector sampling on the first matrix in the frequency domain dimension.

[0204] In another optional implementation, the second information may include a second bitmap. All bits in the second bitmap correspond one-to-one to all first frequency domain units in the first frequency domain unit set. All second frequency domain units in the second frequency domain unit set are all target first frequency domain units in the first frequency domain unit set. In addition, the bits corresponding to the first target first frequency domain units in the first frequency domain unit set adopt a third value, and the bits corresponding to the second bitmap of the other first frequency domain units in the first frequency domain unit set except the above-mentioned target first frequency domain units adopt a fourth value. Here, the third value and the fourth value are different. That is to say, the terminal device can select the target first frequency domain units corresponding to the bits in the second bitmap whose values ​​are all the third value, and form the second frequency domain unit set based on the selected target first frequency domain units.

[0205] Exemplarily, it is assumed that the second bitmap includes bit 1, bit 2 to bit p corresponding to frequency domain unit 1 to frequency domain unit p, respectively. Among them, the values ​​of bit 1, bit 4, bit 6, bit 9, and bit 11 are all 1, and the values ​​of the remaining other bits are all 0. When the above-mentioned third value is 1, the terminal device can select frequency domain unit 1, frequency domain unit 4, frequency domain unit 6, and frequency domain unit 9 from the first frequency domain unit set based on the second bitmap, and form a second frequency domain unit set based on these frequency domain units.

[0206] It should be noted that this method is applicable to the case of performing non-uniform vector sampling in the frequency domain dimension on the first matrix.

[0207] It should be supplemented that, in some optional implementations, the above-mentioned second information may be configured by the network device. In this case, before step S211, the network device may also generate and send the second information to the terminal device. Accordingly, the terminal device may receive the second information from the network device. Optionally, in the case where the second information is configured by the network device and the second information includes the number of frequency domain unit intervals and the identifier of the starting frequency domain unit, the number of frequency domain unit intervals and the identifier of the starting frequency domain unit may be configured by the same signaling, or may be configured by different signaling. For example, the network device may configure the above-mentioned number of frequency domain unit intervals for the terminal device through RRC signaling, and configure the above-mentioned identifier of the starting frequency domain unit for the terminal device through DCI signaling. It should be understood that the network device may also use other methods to configure the above-mentioned second information for the terminal device, and this application does not impose specific restrictions on this. In some other optional implementations, the above-mentioned second information may also be specified by the communication protocol between the network device and the terminal device.

[0208] After determining the second frequency domain unit set, the terminal device may perform vector sampling on the first matrix based on the second frequency domain unit set to obtain a second matrix. For example, the terminal device may determine column vectors in the first matrix corresponding to the plurality of second frequency domain units included in the second frequency domain unit set, and compose a second matrix based on these determined column vectors, thereby completing vector sampling of the frequency domain dimension of the first matrix.

[0209] Furthermore, after acquiring the second matrix, the terminal device may determine the first joint space-frequency vector set according to the second matrix.

[0210] Exemplarily, the terminal device may first calculate the statistical information matrix corresponding to the second matrix. It should be understood that the number of rows of the statistical information matrix is ​​equal to the product m*ps of the number m of the first antenna ports included in the first antenna port set and the number of second frequency domain units included in the above-mentioned second frequency domain unit set (here assumed to be ps, ps is a positive integer greater than or equal to 2, and ps is less than p), and the number of columns of the statistical information matrix is ​​also equal to the product m*ps. After obtaining the statistical information matrix corresponding to the second matrix, the terminal device may perform eigenvector extraction on the statistical information matrix to obtain the above-mentioned first space-frequency joint vector set. Specifically, the terminal device may first determine the P1 eigenvalues ​​with the largest values ​​based on the statistical information matrix. Here, for the description of the parameter P1, please refer to the previous text and will not be repeated here. Then, the terminal device may extract the eigenvectors corresponding to these P1 eigenvalues ​​and form the above-mentioned first space-frequency joint vector set.

[0211] Optionally, the statistical information matrix corresponding to the second matrix may be a space-frequency domain statistical covariance matrix obtained by transforming the second matrix.

[0212] Furthermore, after obtaining the above-mentioned first matrix, the terminal device can also determine the above-mentioned first frequency domain vector set based on the first matrix. Specifically, the terminal device can first calculate the frequency domain statistical covariance matrix corresponding to the first matrix based on the first matrix. Here, the number of rows and columns of the frequency domain statistical covariance matrix are both equal to f. Then, the terminal device can extract the eigenvectors of the frequency domain statistical covariance matrix corresponding to the first matrix to obtain the above-mentioned first spatial domain vector set. Specifically, the terminal device can first determine the P3 eigenvalues ​​with the largest values ​​based on the spatial domain statistical covariance matrix. Here, P3 is a positive integer greater than or equal to 1. It should be understood that P3 can be configured by the network device, or it can be specified in the communication protocol between the network device and the terminal device, and this application does not impose specific restrictions on this. Then, the terminal device can extract the eigenvectors corresponding to these P3 eigenvalues ​​and form the above-mentioned first frequency domain vector set.

[0213] Furthermore, after determining the above-mentioned first spatial domain joint vector set and the first frequency domain vector set, the terminal device can determine the first indication information corresponding to the first spatial-frequency joint vector set and the third indication information corresponding to the first frequency domain vector set, and then generate the first CSI containing the above-mentioned first indication information and the second indication information.

[0214] Here, the specific process of the terminal device determining the first indication information can be found in the previous text and will not be repeated here.

[0215] Similarly, the third indication information includes fifth sub-indication information of the third common vector subset and sixth sub-indication information of the fourth weighting coefficient. The third common vector subset and the fourth weighting coefficient may be used by the network device to determine the first set of frequency-domain vectors. The fifth sub-indication information may be used to indicate a third common vector subset from the entire set of third common vectors. Optionally, each common vector in the entire set of third common vectors may be a DFT vector.

[0216] In the above implementation, when only vector extraction of the frequency domain dimension is performed on the first matrix, the network device does not need to use the first spatial domain vector set when reconstructing the matrix, so the first CSI only needs to report the first spatial-frequency joint vector set and the first frequency-spatial domain set. This can also avoid the waste of communication resources caused by reporting an invalid first spatial domain vector set.

[0217] Scenario 1.1.3:

[0218] In this scenario, the first CSI may include first indication information, second indication information, and third indication information. In this case, the first matrix may correspond to the first antenna port set and the first frequency domain unit set, while the second matrix may correspond to the second antenna port set and the second frequency domain unit set. Furthermore, the second antenna port set is a subset of the first antenna port set, and the second frequency domain unit set is a subset of the first frequency domain unit set. In other words, the second matrix is ​​obtained by the terminal device sampling the first matrix by vectors in the spatial and frequency domain dimensions.

[0219] In a specific implementation, after receiving the first CSI-RS, the terminal device can obtain the measurement result of the first CSI-RS and determine the first matrix based on the measurement result of the first CSI-RS. Here, the first matrix can be a channel matrix corresponding to a terminal antenna port or a precoding matrix corresponding to a stream / layer determined by the terminal device based on the measurement result of the first CSI-RS.

[0220] Furthermore, the terminal device may perform vector sampling on the first matrix to obtain the second matrix.

[0221] In an optional implementation, the second matrix can be obtained by the terminal device by performing vector sampling on the first matrix based on the first information and the second information. The first information is mainly used to indicate the second antenna port set from the first antenna port set, and the second information is mainly used to indicate the second frequency domain unit set from the first frequency domain unit set. That is, the terminal device can determine the second antenna port set from the first antenna port set based on the first information, and determine the second frequency domain unit set from the first frequency domain unit set based on the second information. Then, based on the second antenna port set and the second frequency domain unit set, the first matrix is ​​vector sampled in the spatial dimension and the frequency domain dimension to obtain the second matrix.

[0222] Here, for the description of the first information and the second information, as well as the specific process of the terminal device determining the second antenna port set and the second frequency domain unit set based on the first information and the second information, please refer to the corresponding descriptions in the previous scenarios 1.1.1 and 1.1.2, and will not be repeated here.

[0223] After determining the second antenna port set and the second frequency domain unit, the terminal device can perform vector sampling on the first matrix according to the second antenna port set and the second frequency domain unit set to obtain a second matrix. Specifically, the terminal device can determine the row vectors in the first matrix corresponding to the multiple second antenna ports included in the second antenna port set, and form a spatially sampled matrix based on these determined row vectors, thereby completing the vector sampling of the spatial domain dimension of the first matrix. Then, the terminal device can determine the column vectors in this spatially sampled matrix corresponding to the multiple second frequency domain units included in the second frequency domain unit set, and form the second matrix based on these determined column vectors, thereby completing the vector sampling of the spatial domain dimension and the frequency domain dimension of the first matrix.

[0224] Furthermore, after determining to obtain the second matrix, the terminal device may determine the first joint space-frequency vector set according to the second matrix.

[0225] Exemplarily, the terminal device may first calculate the statistical information matrix corresponding to the second matrix. It should be understood that the number of rows of the statistical information matrix is ​​equal to the number of second antenna ports contained in the second antenna port set (here it is assumed to be ms, it should be understood that ms should be less than m) and the number of second frequency domain units ps contained in the above-mentioned second frequency domain unit set, which is the product ms*ps, and the number of columns of the statistical information matrix is ​​also equal to the product ms*ps. After obtaining the statistical information matrix corresponding to the second matrix, the terminal device may perform eigenvector extraction on the statistical information matrix to obtain the above-mentioned first space-frequency joint vector set. Specifically, the terminal device may first determine the P1 eigenvalues ​​with the largest values ​​based on the statistical information matrix. Then, the terminal device may extract the eigenvectors corresponding to these P1 eigenvalues ​​and form the above-mentioned first space-frequency joint vector set.

[0226] Optionally, the statistical information matrix corresponding to the second matrix may be a space-frequency domain statistical covariance matrix obtained by transforming the second matrix.

[0227] Furthermore, after obtaining the first matrix, the terminal device may also determine the first spatial domain vector set and the first frequency domain vector set based on the first matrix. The process of the terminal device determining the first spatial domain vector set and the first frequency domain vector set based on the first matrix can be found in the corresponding description above and will not be repeated here.

[0228] Furthermore, after determining the above-mentioned first spatial domain joint vector set, the first spatial domain vector set and the first frequency domain vector set, the terminal device can determine the first indication information corresponding to the first spatial-frequency joint vector set, the second indication information corresponding to the first spatial domain vector set and the third indication information corresponding to the first frequency domain vector set, and then generate the first CSI including the above-mentioned first indication information, second indication information and third indication information.

[0229] Here, the process of the terminal device determining the first indication information corresponding to the first space-frequency joint vector set, the second indication information corresponding to the first space domain vector set, and the third indication information corresponding to the first frequency domain vector set can be referred to the corresponding description in the previous text, and will not be repeated here.

[0230] S212: The terminal device sends the first CSI to the network device. Correspondingly, the network device receives the first CSI.

[0231] After determining the first CSI, the terminal device may send the first CSI to the network device. The terminal device may send the first CSI to the network device based on the CSI reporting configuration information configured by the network device. Correspondingly, the network device may receive the first CSI from the terminal device.

[0232] It should be noted that in the channel state information reporting method provided in the present application, the network device will configure two different CSI reports for the terminal device, and these two different CSI reports will correspond to two different CSI reporting configuration information. One CSI report can be used for the terminal device to send the above-mentioned first CSI to the network device. For ease of understanding, this CSI report is expressed as the first CSI report. It should be understood that the first CSI report provided in the present application is mainly used for the terminal device to report to the network device a vector set that can be used to characterize the channel matrix or the precoding matrix. Each time the terminal device completes the first CSI report, it reports a vector set to the network device, and this vector set can be used by the network device to recover a channel matrix or a precoding matrix. Taking the above-mentioned first CSI as an example, the terminal device sends the above-mentioned first CSI to the network device through a first CSI report, thereby completing the reporting of the first space-frequency joint vector set and the first space domain vector set and / or the first frequency domain vector set.

[0233] Another type of CSI reporting can be used by the terminal device to send a second CSI to the network device. For ease of understanding, this type of CSI reporting is referred to as a second CSI reporting. This second CSI reporting will be further explained later.

[0234] It should also be noted that the specific behavior of the first CSI report (reporting method, reporting time, etc.) can be determined by the CSI reporting configuration information corresponding to the first CSI report, and the terminal device can complete each first CSI report according to the CSI reporting configuration information corresponding to the first CSI report.

[0235] S213: The network device sends a second CSI-RS to the terminal device. Correspondingly, the terminal device receives the second CSI-RS.

[0236] The network device can generate a second CSI-RS and send the second CSI-RS to the terminal device on the corresponding time-frequency resources. Correspondingly, the terminal device will also receive the second CSI-RS from the network device on the time-frequency resources. The second CSI-RS can be used for the terminal device to report the second CSI. It should be understood that the second CSI-RS and the first CSI-RS mentioned above can be different CSI-RS transmitted at different times, or they can be the same CSI-RS. In the case of different CSI-RSs, the second CSI-RS is mainly used for the terminal device to report the second CSI, and the first CSI-RS mentioned above is mainly used for the terminal device to report the first CSI. The time-frequency resources for transmitting the second CSI-RS are indicated by the configuration information of the second CSI-RS.

[0237] In a first optional implementation, the second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set. That is, the second CSI-RS and the first CSI-RS correspond to the same antenna port set and frequency domain unit set. It can also be understood that the first CSI-RS and the second CSI-RS are the same CSI-RS transmitted at different times.

[0238] In a second optional implementation, the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the above-mentioned second matrix, and the second CSI-RS corresponds to the same frequency domain unit set as the second matrix. In other words, the second CSI-RS is the sparse first CSI-RS, that is, the second CSI-RS is obtained after the first CSI-RS is sparsed. The antenna port set corresponding to the second CSI-RS is obtained by sampling the antenna port set corresponding to the first CSI-RS, and / or the frequency domain unit set corresponding to the second CSI-RS is obtained by sampling the frequency domain unit set corresponding to the first CSI-RS. Moreover, the sampling method used is the same as the sampling method used for the first matrix described above. It should be noted here that when the network device extracts the antenna port set corresponding to the first CSI-RS in the same way and keeps the identifiers of each extracted antenna port unchanged, the antenna port set corresponding to the second CSI-RS can be the same as the antenna port set corresponding to the second matrix.

[0239] Optionally, in the above scenario 1.1.1, the network device may extract the elements corresponding to the second antenna port set from the first CSI-RS to form the second CSI-RS.

[0240] Optionally, in the above scenario 1.1.2, the network device may extract elements corresponding to the second frequency domain unit set from the first CSI-RS to form the above second CSI-RS.

[0241] Optionally, in the above scenario 1.1.3, the network device may extract elements corresponding to the second antenna port set and the second frequency domain unit set from the first CSI-RS to form the above second CSI-RS.

[0242] It should be noted that the first CSI-RS and the second CSI-RS have the same quasi-co-location relationship. Alternatively, the first CSI-RS can be quasi-co-located with the second CSI-RS. Alternatively, the first CSI-RS and the second CSI-RS can be configured in the same resource set (i.e., resource set).

[0243] In the above implementation, since the second CSI-RS is sparse, the number of corresponding antenna ports and / or the number of occupied frequency domain units are smaller, so the overhead occupied is smaller, which is more conducive to the rational use of communication resources.

[0244] It should be understood that in actual implementation, step S213 can be executed after step S212 or before step S212. This application does not impose any specific restrictions on the execution sequence of step S212 and step S213. The drawings of this application uniformly illustrate step S213 as being executed after step S212.

[0245] S214, the terminal device determines the second CSI including the fourth indication information corresponding to the first weighting coefficient.

[0246] In some feasible implementations, after receiving the second CSI-RS, the terminal device may determine the second CSI based on the measurement result of the second CSI-RS and the first set of space-frequency joint vectors. The second CSI includes fourth indication information corresponding to the first weighting coefficient, and the first weighting coefficient may be determined based on the first set of space-frequency joint vectors and the measurement result of the second CSI-RS.

[0247] The following describes the process of determining the second CSI by the terminal device in combination with different implementation methods of the second CSI-RS and scenarios 1.1.1 to 1.1.3 described above.

[0248] Implementation method 1.2.1 of the second CSI-RS:

[0249] In this implementation, the second CSI-RS corresponds to the above-mentioned first antenna port set and the first frequency domain unit set. In this case, the above-mentioned first weighting coefficient can be determined based on the first space-frequency joint vector set and the third matrix. The third matrix is ​​obtained by the terminal device performing vector sampling on the fourth matrix, and the fourth matrix is ​​determined by the terminal device based on the second CSI-RS. For example, the fourth matrix can be determined by the terminal device based on the measurement result of the second CSI-RS. The fourth matrix corresponds to the first antenna port set and the first frequency domain unit set. In other words, the fourth matrix and the second CSI-RS correspond to the same antenna port set and frequency domain unit set. Here, the fourth matrix can be the channel matrix corresponding to a certain terminal antenna port or the precoding matrix corresponding to a certain stream / layer determined by the terminal device based on the measurement result of the second CSI-RS. It should be understood that when the first matrix is ​​a channel matrix, the above-mentioned fourth matrix is ​​the channel matrix. When the first matrix is ​​a precoding matrix, the above-mentioned fourth matrix is ​​the precoding matrix.

[0250] Optionally, in the scenario 1.1.1 described above, after obtaining the measurement result of the second CSI-RS, the terminal device may determine the fourth matrix based on the measurement result of the second CSI-RS. Then, the terminal device may perform vector extraction of the spatial dimension of the fourth matrix based on the first information described above to obtain the third matrix. In this case, the third matrix corresponds to the second antenna port set and the first frequency domain unit set. Here, the specific process of the terminal device performing vector extraction of the spatial dimension of the fourth matrix based on the first information to obtain the third matrix is ​​similar to the process of the terminal device performing vector sampling of the spatial dimension of the first matrix based on the first information to obtain the second matrix described above. In order to avoid redundancy, it will not be repeated here.

[0251] After obtaining the third matrix, the terminal device can determine the first weighting coefficient based on the third matrix and the first set of joint space-frequency vectors. For example, the terminal device can use the weighting coefficient obtained by projecting or mapping the third matrix onto the first set of joint space-frequency vectors as the first weighting coefficient. It can be understood that the third matrix is ​​the product of the first set of joint space-frequency vectors and the first weighting coefficient.

[0252] Optionally, in the scenario 1.1.2 described above, after obtaining the measurement result of the second CSI-RS, the terminal device may determine the fourth matrix based on the measurement result of the second CSI-RS. Here, the fourth matrix may be a channel matrix corresponding to a certain terminal antenna port or a precoding matrix corresponding to a certain stream / layer determined by the terminal device based on the measurement result of the second CSI-RS. Then, the terminal device may perform vector extraction of the frequency domain dimension on the fourth matrix based on the second information described above to obtain the third matrix. In this case, the third matrix corresponds to the first antenna port set and the second frequency domain unit set. Here, the specific process of the terminal device performing vector extraction of the frequency domain dimension on the fourth matrix based on the second information to obtain the third matrix is ​​similar to the process of the terminal device performing vector sampling of the frequency domain dimension on the first matrix based on the second information to obtain the second matrix described above. In order to avoid redundancy, it will not be repeated here.

[0253] After obtaining the third matrix, the terminal device can determine the first weighting coefficient according to the third matrix and the first space-frequency joint vector set. The specific process can be found in the corresponding description above and will not be repeated here.

[0254] Optionally, in the scenario 1.1.3 described above, after obtaining the measurement result of the second CSI-RS, the terminal device may determine the fourth matrix based on the measurement result of the second CSI-RS. Here, the fourth matrix may be a channel matrix corresponding to a certain terminal antenna port or a precoding matrix corresponding to a certain stream / layer determined by the terminal device based on the measurement result of the second CSI-RS. Then, the terminal device may perform vector extraction of the spatial and frequency domain dimensions of the fourth matrix based on the first information and the second information described above to obtain the third matrix. In this case, the third matrix corresponds to the second antenna port set and the second frequency domain unit set. Here, the specific process of the terminal device performing vector extraction of the spatial and frequency domain dimensions of the fourth matrix based on the first information and the second information to obtain the third matrix is ​​similar to the process of the terminal device performing vector sampling of the spatial and frequency domain dimensions of the first matrix based on the first information and the second information to obtain the second matrix described above. In order to avoid redundancy, it will not be repeated here.

[0255] After obtaining the third matrix, the terminal device can determine the first weighting coefficient according to the third matrix and the first space-frequency joint vector set. The specific process can be found in the corresponding description above and will not be repeated here.

[0256] Furthermore, after determining the first weighting coefficient, the terminal device may generate fourth indication information corresponding to the first weighting coefficient and generate second CSI including the fourth indication information. Here, the fourth indication information may include amplitude information and phase information of the first weighting coefficient.

[0257] Implementation method 1.2.2 of the second CSI-RS:

[0258] In this implementation, the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same set of frequency domain units.

[0259] Optionally, in the above-mentioned scenario 1.1.1, scenario 1.1.2 or scenario 1.1.3, after obtaining the measurement result of the second CSI-RS, the terminal device may determine a fourth matrix based on the measurement result of the second CSI-RS. Here, the fourth matrix may be a channel matrix corresponding to a certain terminal antenna port or a precoding matrix corresponding to a certain stream / layer determined by the terminal device based on the measurement result of the second CSI-RS. Then, the terminal device can determine the above-mentioned first weighting coefficient based on the fourth matrix and the above-mentioned first space-frequency joint vector set. For example, the terminal device may determine the weighting coefficient obtained by the projection or projection of the fourth matrix on the first space-frequency joint vector set as the above-mentioned first weighting coefficient. It can be understood that the fourth matrix is ​​the product of the first space-frequency joint vector set and the first weighting coefficient.

[0260] Furthermore, after determining the first weighting coefficient, the terminal device may generate fourth indication information corresponding to the first weighting coefficient and generate second CSI including the fourth indication information. Similarly, the fourth indication information may include amplitude information and phase information of the first weighting coefficient.

[0261] S215: The terminal device sends the second CSI to the network device. Correspondingly, the network device receives the second CSI.

[0262] In some feasible implementations, after determining the second CSI, the terminal device may send the second CSI to the network device. Specifically, the terminal device may send the second CSI to the network device based on the second CSI reporting configured by the network device. Accordingly, the network device may receive the second CSI from the terminal device.

[0263] It should be noted that the second CSI reporting provided in this application is mainly used for the terminal device to report the weighted coefficients corresponding to the vector set that can be used to represent the precoding matrix to the network device. Each time the terminal device completes the second CSI reporting, it reports the weighted coefficients corresponding to the first space-frequency joint vector set to the network device. Here, the specific behavior of the second CSI reporting (reporting method, reporting time, etc.) can be determined by the CSI reporting configuration information corresponding to the second CSI reporting. The terminal device can complete each second CSI reporting according to the CSI reporting configuration information corresponding to the second CSI reporting.

[0264] For some possible implementations, see Figure 3 , Figure 3 This is another flow chart of a channel state information CSI reporting method provided by this application. Figure 3 Said method further comprises the following steps:

[0265] S216: The network device determines a fourth matrix or a fifth matrix according to the first CSI and the second CSI.

[0266] In some feasible implementations, after receiving the first CSI and the second CSI, the network device may determine a fourth matrix or a fifth matrix based on the first CSI and the second CSI. The first weighting coefficient, the first space-frequency joint vector, and at least one of the first space domain vector set and the first frequency domain vector set may be used to determine the fourth matrix. Furthermore, the fourth matrix is ​​determined by the terminal device based on the measurement result of the second CS-RS. Alternatively, the first weighting coefficient, the first space-frequency joint vector set, and at least one of the first space domain vector set and the first frequency domain vector set are used to determine the fifth matrix corresponding to the second CSI-RS. Furthermore, the fifth matrix is ​​determined based on the fourth matrix, and the fourth matrix is ​​determined based on the measurement result of the second CSI-RS. It should be understood that when the first matrix is ​​a channel matrix, the fifth matrix is ​​also a channel matrix. When the first matrix is ​​a precoding matrix, the fifth matrix is ​​also a precoding matrix.

[0267] In actual implementation, combined with the scenarios 1.1.1, 1.1.2, 1.1.3 and the two implementation methods of the second CSI-RS described above, the specific process of the network device determining the fourth matrix or the fifth matrix based on the first CSI and the second CSI may include the following situations.

[0268] Case 1.3.1: The first CSI is implemented as described in Scenario 1.1.1 above, and the second CSI-RS uses the implementation method described in Scenario 1.2.1 above.

[0269] In this case, after obtaining the first CSI and the second CSI, the network device can determine the first space-frequency joint vector set, the first space domain vector set and the first weighting coefficient according to the first indication information, the second indication information and the fourth indication information.

[0270] The network device may then determine a third matrix based on the first weighting coefficients and the first set of joint space-frequency vectors. Here, the third matrix corresponds to the second set of antenna ports and the first set of frequency-domain elements. For example, the network device may determine the third matrix as the product of the first weighting coefficients and the first set of joint space-frequency vectors.

[0271] Furthermore, the network device may determine a fourth matrix according to the third matrix, the first spatial vector set and the first information.

[0272] Optionally, the network device may first perform vector sampling on the first spatial vector set based on the first information to obtain a second spatial vector set. The first spatial vector set corresponds to the first antenna port set, and the second spatial vector set corresponds to the second antenna port set. For example, the network device may extract row vectors from the first spatial vector set that correspond to each second antenna port set in the second antenna port set to form the second spatial vector set.

[0273] Then, the network device may perform the following spatial domain reconstruction operation on the first vector k1 corresponding to any first frequency domain unit i1 in the first frequency domain unit set in the third matrix: process the first vector k1 according to the first spatial domain vector set and the second spatial domain vector set to obtain the second vector k2. Here, the second vector k2 corresponds to the first antenna port set and the first frequency domain unit i1. Then, the network device may determine the fourth matrix based on the multiple second vectors obtained by performing the above-mentioned spatial domain reconstruction operation on the first vector corresponding to each first frequency domain unit in the first frequency domain unit set. In other words, the network device may perform the above-mentioned spatial domain reconstruction operation on the first vector corresponding to each first frequency domain unit in the first frequency domain unit set in the third matrix to obtain the second vector corresponding to each first frequency domain unit, and determine the above-mentioned fourth matrix based on the second vector corresponding to each first frequency domain unit.

[0274] The first vector k1, the second vector k2, the first spatial vector set, and the second spatial vector set satisfy the following formula (1):

[0275] k2=S1×(S2) + ×k1 (1)

[0276] Here, S1 is the first spatial domain vector set mentioned above, S2 is the second spatial domain vector set mentioned above, (S2) + is the pseudo-inverse of the second spatial vector set.

[0277] That is to say, in actual implementation, when the network device performs the above-mentioned spatial domain reconstruction operation on the first vector corresponding to each first frequency domain unit in the first frequency domain unit set in the third matrix, it can calculate the second vector corresponding to each first frequency domain unit based on the above formula (1).

[0278] Case 1.3.2: The first CSI is implemented as described in Scenario 1.1.1 above, and the second CSI-RS uses the implementation method described in Scenario 1.2.2 above.

[0279] In this case, after obtaining the first CSI and the second CSI, the network device can determine the first space-frequency joint vector set, the first space domain vector set and the first weighting coefficient according to the first indication information, the second indication information and the fourth indication information.

[0280] The network device may then determine a fourth matrix based on the first weighting coefficients and the first set of joint space-frequency vectors. Here, the fourth matrix corresponds to the second antenna port set and the first set of frequency domain elements. For example, the network device may determine the fourth matrix as the product of the first weighting coefficients and the first set of joint space-frequency vectors.

[0281] Furthermore, the network device may determine a fifth matrix according to the fourth matrix, the first spatial vector set and the first information.

[0282] Optionally, the network device may first perform vector sampling on the first spatial domain vector set according to the first information to obtain the second spatial domain vector set. The specific process can be found in the specific process described in 1.3.1 above, and will not be repeated here.

[0283] Then, the network device may perform the following spatial domain reconstruction operation on the third vector k3 corresponding to any first frequency domain unit i1 in the first frequency domain unit set in the fourth matrix: process the third vector k3 according to the first spatial domain vector set and the second spatial domain vector set to obtain a fourth vector k4. Here, the fourth vector k4 corresponds to the first antenna port set and the first frequency domain unit i1. Then, the network device may determine the fifth matrix based on the multiple fourth vectors obtained by performing the above-mentioned spatial domain reconstruction operation on the third vector corresponding to each first frequency domain unit in the first frequency domain unit set. In other words, the network device may perform the above-mentioned spatial domain reconstruction operation on the third vector corresponding to each first frequency domain unit in the first frequency domain unit set in the fourth matrix to obtain the fourth vector corresponding to each first frequency domain unit, and determine the above-mentioned fourth matrix based on the second vector corresponding to each first frequency domain unit.

[0284] The third vector k3, the fourth vector k4, the first spatial vector set, and the second spatial vector set satisfy the following formula (2):

[0285] k4=S1×(S2) + ×k3 (2)

[0286] Here, S1 is the first spatial domain vector set mentioned above, S2 is the second spatial domain vector set mentioned above, (S2) + is the pseudo-inverse of the second spatial vector set.

[0287] That is to say, in actual implementation, when the network device performs the above-mentioned spatial domain reconstruction operation on the third vector corresponding to each first frequency domain unit in the first frequency domain unit set in the fourth matrix, it can calculate the fourth vector corresponding to each first frequency domain unit based on the above formula (2).

[0288] Case 1.3.3: The first CSI is implemented as described in Scenario 1.1.2 above, and the second CSI-RS uses the implementation method described in Scenario 1.2.1 above.

[0289] In this case, after obtaining the first CSI and the second CSI, the network device can determine the first space-frequency joint vector set, the first frequency domain vector set and the first weighting coefficient according to the first indication information, the third indication information and the fourth indication information.

[0290] The network device may then determine a third matrix based on the first weighting coefficients and the first set of joint space-frequency vectors. Here, the third matrix corresponds to the first set of antenna ports and the second set of frequency domain elements. For example, the network device may determine the third matrix as the product of the first weighting coefficients and the first set of joint space-frequency vectors.

[0291] Furthermore, the network device may determine a fourth matrix according to the third matrix, the first spatial vector set and the first information.

[0292] Optionally, the network device may first perform vector sampling on the first frequency domain vector set based on the second information to obtain a second frequency domain vector set. The first frequency domain vector set corresponds to a first frequency domain unit set, and the second frequency domain vector set corresponds to a second frequency domain unit set. Specifically, the network device may extract row vectors from the first frequency domain vector set that correspond to each second frequency domain unit in the second frequency domain unit set to form the second frequency domain vector set.

[0293] Then, the network device may perform the following frequency domain reconstruction operation on the fifth vector k5 corresponding to any first antenna port i2 in the first antenna port set in the third matrix: process the fifth vector k5 according to the first frequency domain vector set and the second frequency domain vector set to obtain a sixth vector k6. The sixth vector k6 corresponds to the first antenna port i2 and the first frequency domain unit set. Then, the network device may determine the fourth matrix based on multiple sixth vectors obtained by performing the above-mentioned frequency domain reconstruction operation on the fifth vector corresponding to each first antenna port in the first antenna port set. In other words, the network device may perform the above-mentioned frequency domain reconstruction operation on the fifth vector corresponding to each first antenna port in the first antenna port set in the third matrix to obtain the sixth vector corresponding to each first antenna port, and determine the fourth matrix based on the sixth vector corresponding to each first antenna port.

[0294] The sixth vector k6, the fifth vector k5, the first frequency domain vector set, and the second frequency domain vector set satisfy the following formula (3):

[0295] k6=F1×(F2) + ×k5 (3)

[0296] Among them, F1 is the first frequency domain vector set, F2 is the second frequency domain vector set, (F2) + is the pseudo-inverse of the second frequency domain vector set.

[0297] That is to say, in actual implementation, when the network device performs the above-mentioned spatial domain reconstruction operation on the fifth vector corresponding to each first antenna port in the first antenna port set in the third matrix, it can calculate the sixth vector corresponding to each first antenna port based on the above formula (3).

[0298] Case 1.3.4: The first CSI is implemented as described in Scenario 1.1.2 above, and the second CSI-RS uses the implementation method described in Scenario 1.2.2 above.

[0299] In this case, after obtaining the first CSI and the second CSI, the network device can determine the first space-frequency joint vector set, the first frequency domain vector set and the first weighting coefficient according to the first indication information, the third indication information and the fourth indication information.

[0300] The network device may then determine a fourth matrix based on the first weighting coefficients and the first set of joint space-frequency vectors. Here, the fourth matrix corresponds to the first set of antenna ports and the second set of frequency domain elements. For example, the network device may determine the fourth matrix as the product of the first weighting coefficients and the first set of joint space-frequency vectors.

[0301] Furthermore, the network device may determine a fifth matrix corresponding to the second CSI-RS according to the fourth matrix, the first spatial vector set, and the second information.

[0302] Optionally, the network device may first perform vector sampling on the first frequency domain vector set according to the second information to obtain the second frequency domain vector set. The specific process can be found in the corresponding description in 1.3.3 above, which will not be repeated here.

[0303] Then, the network device may perform the following frequency domain reconstruction operation on the seventh vector k7 corresponding to any first antenna port i2 in the first antenna port set in the fourth matrix: process the seventh vector k7 according to the first frequency domain vector set and the second frequency domain vector set to obtain an eighth vector k8. The eighth vector k8 corresponds to the first antenna port i2 and the first frequency domain unit set. Then, the network device may determine the fifth matrix based on multiple eighth vectors obtained by performing the above-mentioned frequency domain reconstruction operation on the seventh vector corresponding to each first antenna port in the first antenna port set. In other words, the network device may perform the above-mentioned frequency domain reconstruction operation on the seventh vector corresponding to each first antenna port in the first antenna port set in the fourth matrix to obtain the eighth vector corresponding to each first antenna port, and determine the fifth matrix based on the eighth vector corresponding to each first antenna port.

[0304] The seventh vector k7, the eighth vector k8, the first frequency domain vector set, and the second frequency domain vector set satisfy the following formula (4):

[0305] k8=F1×(F2) + ×k7 (4)

[0306] Among them, F1 is the first frequency domain vector set, F2 is the second frequency domain vector set, (F2) + is the pseudo-inverse of the second frequency domain vector set.

[0307] That is to say, in actual implementation, when the network device performs the above-mentioned spatial domain reconstruction operation on the seventh vector corresponding to each first antenna port in the first antenna port set in the fourth matrix, it can calculate the eighth vector corresponding to each first antenna port based on the above-mentioned formula (4).

[0308] Case 1.3.5: The first CSI is implemented as described in Scenario 1.1.3 above, and the second CSI-RS uses the implementation method described in Scenario 1.2.1 above.

[0309] In this case, after obtaining the above-mentioned first CSI and second CSI, the network device can determine the above-mentioned first space-frequency joint vector set, first space domain vector set, first frequency domain vector set and first weighting coefficient based on the first indication information, second indication information, third indication information and fourth indication information.

[0310] The network device may then determine a third matrix based on the first weighting coefficients and the first set of joint space-frequency vectors. Here, the third matrix corresponds to the second set of antenna ports and the second set of frequency-domain units. For example, the network device may determine the third matrix as the product of the first weighting coefficients and the first set of joint space-frequency vectors.

[0311] Furthermore, the network device may determine a fourth matrix according to the third matrix, the first spatial domain vector set, the first frequency domain vector set, the first information, and the second information.

[0312] Optionally, the network device may perform vector sampling on the first spatial vector set according to the first information to obtain the second spatial vector set. Specific processes can be found in the corresponding processes described in 1.3.1 above, and will not be repeated here.

[0313] Then, the network device may perform the following spatial domain reconstruction operation on the ninth vector k9 corresponding to any second frequency domain unit i3 in the second frequency domain unit set in the third matrix: the ninth vector k9 is processed according to the first spatial domain vector set and the second spatial domain vector set to obtain the tenth vector k10. Here, the tenth vector k10 corresponds to the first antenna port set and the second frequency domain unit i3. Then, the network device may determine the first transition matrix based on the multiple tenth vectors obtained by performing the spatial domain reconstruction operation on the ninth vector corresponding to each second frequency domain unit in the second frequency domain unit set. Here, the first transition matrix corresponds to the above-mentioned first antenna port set and the above-mentioned second frequency domain unit set. That is, the network device may perform the above-mentioned spatial domain reconstruction operation on the ninth vector corresponding to each second frequency domain unit in the second frequency domain unit set in the third matrix to obtain the tenth vector corresponding to each second frequency domain unit, and construct the above-mentioned first transition matrix based on the tenth vector corresponding to each second frequency domain unit.

[0314] Among them, the ninth vector k9, the tenth vector k10, the first spatial vector set and the second spatial vector set satisfy the following formula (5):

[0315] k10=S1×(S2) + ×k9 (5)

[0316] Among them, S1 is the first spatial domain vector set, S2 is the second spatial domain vector set, (S2) + is the pseudo-inverse of the second spatial vector set.

[0317] That is to say, in actual implementation, when the network device performs the above-mentioned spatial domain reconstruction operation on the ninth vector corresponding to each second frequency domain unit in the second frequency domain unit set in the third matrix, it can calculate the tenth vector corresponding to each second frequency domain unit based on the above formula (5).

[0318] Furthermore, the network device may perform vector sampling on the first frequency domain vector set according to the second information to obtain a second frequency domain vector set. Specific processes may refer to the corresponding processes described in 1.3.3 above, and will not be repeated here.

[0319] The network device may then perform the following frequency domain reconstruction operation on the eleventh vector k11 corresponding to any first antenna port i2 in the first antenna port set in the first transition matrix: the eleventh vector k11 is processed according to the first frequency domain vector set and the second frequency domain vector set to obtain a twelfth vector k12. The twelfth vector k12 corresponds to the first antenna port i2 and the first frequency domain element set. Finally, the network device may determine the fourth matrix based on multiple twelfth vectors obtained by performing the frequency domain reconstruction operation on the eleventh vector corresponding to each first antenna port in the first antenna port set.

[0320] Among them, the eleventh vector k11, the twelfth vector k12, the first frequency domain vector set and the second frequency domain vector set satisfy the following formula (6):

[0321] k12=F1×(F2) + ×k11 (6)

[0322] Among them, F1 is the first frequency domain vector set, F2 is the second frequency domain vector set, (F2) + is the pseudo-inverse of the second frequency domain vector set.

[0323] That is to say, in actual implementation, when the network device performs the above-mentioned frequency domain reconstruction operation on the eleventh vector corresponding to each first antenna port in the first antenna port set in the first transition matrix, it can calculate the twelfth vector corresponding to each second frequency domain unit based on the above formula (6).

[0324] It should be noted that the above description describes a scenario in which the network device first performs a spatial domain reconstruction operation on the third matrix to obtain a first transition matrix, and then performs a frequency domain reconstruction operation on the first transition matrix to obtain a fourth matrix. In actual implementation, the network device may also first perform a frequency domain reconstruction operation on the third matrix to obtain a transition matrix, and then perform a spatial domain reconstruction operation on this transition matrix to obtain the aforementioned fourth matrix. Since the specific implementation process of the latter solution is similar to the former, differing only in the timing of the spatial domain reconstruction operation and the frequency domain reconstruction operation, it will not be described in detail here to avoid redundancy.

[0325] Case 1.3.6: The first CSI is implemented as described in Scenario 1.1.3 above, and the second CSI-RS uses the implementation method described in Scenario 1.2.2 above.

[0326] In this case, after obtaining the above-mentioned first CSI and second CSI, the network device can determine the above-mentioned first space-frequency joint vector set, first space domain vector set, first frequency domain vector set and first weighting coefficient based on the first indication information, second indication information, third indication information and fourth indication information.

[0327] The network device may then determine a fourth matrix based on the first weighting coefficients and the first set of joint space-frequency vectors. Here, the fourth matrix corresponds to the second set of antenna ports and the second set of frequency domain units. For example, the network device may determine the fourth matrix as the product of the first weighting coefficients and the first set of joint space-frequency vectors.

[0328] Furthermore, the network device may determine a fifth matrix according to the fourth matrix, the first spatial domain vector set, the first frequency domain vector set, the first information, and the second information.

[0329] Optionally, the network device may perform vector sampling on the first spatial vector set according to the first information to obtain the second spatial vector set. Specific processes can be found in the corresponding processes described in 1.3.1 above, and will not be repeated here.

[0330] Then, the network device may perform the following spatial domain reconstruction operation on the thirteenth vector k13 corresponding to any second frequency domain unit i3 in the second frequency domain unit set in the fourth matrix: the thirteenth vector k13 is processed according to the first spatial domain vector set and the second spatial domain vector set to obtain a fourteenth vector k14. Here, the fourteenth vector k14 corresponds to the first antenna port set and the second frequency domain unit i3. Then, the network device may determine the second transition matrix based on multiple tenth vectors obtained by performing the spatial domain reconstruction operation on the ninth vector corresponding to each second frequency domain unit in the second frequency domain unit set. Here, the second transition matrix corresponds to the above-mentioned first antenna port set and the above-mentioned second frequency domain unit set. That is, the network device may perform the above-mentioned spatial domain reconstruction operation on the thirteenth vector corresponding to each second frequency domain unit in the second frequency domain unit set in the fourth matrix to obtain the fourteenth vector corresponding to each second frequency domain unit, and construct the above-mentioned second transition matrix based on the fourteenth vector corresponding to each second frequency domain unit.

[0331] Among them, the thirteenth vector k13, the fourteenth vector k14, the first spatial vector set and the second spatial vector set satisfy the following formula (7):

[0332] k14=S1×(S2) + ×k13 (7)

[0333] Among them, S1 is the first spatial domain vector set, S2 is the second spatial domain vector set, (S2) + is the pseudo-inverse of the second spatial vector set.

[0334] That is to say, in actual implementation, when the network device performs the above-mentioned spatial domain reconstruction operation on the thirteenth vector corresponding to each second frequency domain unit in the second frequency domain unit set in the fourth matrix, it can calculate the fourteenth vector corresponding to each second frequency domain unit based on the above formula (7).

[0335] Furthermore, the network device may perform vector sampling on the first frequency domain vector set according to the second information to obtain a second frequency domain vector set. Specific processes may refer to the corresponding processes described in 1.3.3 above, and will not be repeated here.

[0336] The network device may then perform the following frequency domain reconstruction operation on the fifteenth vector k15 corresponding to any first antenna port i2 in the first antenna port set in the second transition matrix: the fifteenth vector k15 is processed according to the first frequency domain vector set and the second frequency domain vector set to obtain a sixteenth vector k16. The sixteenth vector k16 corresponds to the first antenna port i2 and the first frequency domain element set. Finally, the network device may determine the fifth matrix based on multiple sixteenth vectors obtained by performing the frequency domain reconstruction operation on the fifteenth vector corresponding to each first antenna port in the first antenna port set.

[0337] Among them, the fifteenth vector k15, the sixteenth vector k16, the first frequency domain vector set and the second frequency domain vector set satisfy the following formula (8):

[0338] k16=F1×(F2) + ×k15 (8)

[0339] Among them, F1 is the first frequency domain vector set, F2 is the second frequency domain vector set, (F2) + is the pseudo-inverse of the second frequency domain vector set.

[0340] That is to say, in actual implementation, when the network device performs the above-mentioned frequency domain reconstruction operation on the fifteenth vector corresponding to each first antenna port in the first antenna port set in the second transition matrix, it can calculate the sixteenth vector corresponding to each second frequency domain unit based on the above formula (8).

[0341] It should be noted that the above description describes a scenario in which the network device first performs a spatial domain reconstruction operation on the fourth matrix to obtain a second transition matrix, and then performs a frequency domain reconstruction operation on the second transition matrix to obtain a fifth matrix. In actual implementation, the network device may also first perform a frequency domain reconstruction operation on the fourth matrix to obtain a transition matrix, and then perform a spatial domain reconstruction operation on this transition matrix to obtain the aforementioned fifth matrix. Since the specific implementation process of the latter solution is similar to the former solution, differing only in the timing of the spatial domain reconstruction operation and the frequency domain reconstruction operation, it will not be described in detail here to avoid redundancy.

[0342] In some feasible implementations, the CSI reporting type of the first CSI reporting provided in this application may be periodic, aperiodic, or semi-persistent. Similarly, the reporting type of the second CSI reporting provided in this application may also be periodic, aperiodic, or semi-persistent.

[0343] In an optional implementation, when the CSI reporting types corresponding to the first CSI and the second CSI are both periodic or semi-continuous, the CSI reporting period corresponding to the first CSI report may be greater than the CSI reporting period corresponding to the second CSI report.

[0344] Since the first CSI reports information indicating the statistical feature basis, which is the statistical feature of the channel in its domain (such as the spatial domain, frequency domain, or joint space-frequency domain), it changes slowly and therefore does not need to be reported frequently. Therefore, in the above implementation, setting the CSI reporting period corresponding to the first CSI report longer can reduce the number of first CSI reports, thereby achieving the purpose of saving communication resources.

[0345] In another optional implementation, when the CSI reporting types corresponding to the first CSI report and the second CSI report are both non-periodic, the CSI reporting interval corresponding to the first CSI report may be greater than the CSI reporting interval corresponding to the second CSI report. It should be understood that in the embodiment of the present application, the CSI reporting interval corresponding to the CSI report refers to the time interval between the terminal device completing two CSI reports. For example, the terminal device completes a first CSI report at time t1, also completes a first CSI report at time t2, and completes another first CSI report at time t3. The difference between time t1 and time t2 is a CSI reporting interval of the first CSI report, and the difference between time t2 and time t3 is another CSI reporting interval of the first CSI report. It should be understood that one CSI report may correspond to multiple CSI reporting intervals, and the corresponding multiple CSI reporting intervals may be partially the same. Based on this, the CSI reporting interval corresponding to the first CSI reporting is greater than the CSI reporting interval corresponding to the second CSI reporting. It can be understood that some or all of all CSI reporting intervals corresponding to the first CSI reporting are greater than all CSI reporting intervals corresponding to the second CSI reporting.

[0346] Furthermore, the CSI-RS corresponding to the first CSI report (including the first CSI-RS described above) and the CSI-RS corresponding to the second CSI report (including the second CSI-RS described above) have the same quasi-co-location relationship. Alternatively, the CSI-RS corresponding to the second CSI report may be quasi-co-located with the CSI-RS corresponding to the first CSI report.

[0347] In some feasible implementations, some other configuration items corresponding to the first CSI report and the second CSI report may also be the same or different.

[0348] Optionally, the reporting content (ie, reportQuantity) corresponding to the first CSI report and the second CSI report is different.

[0349] Optionally, the CSI reporting types corresponding to the first CSI report and the second CSI report are the same or different. In other words, the values ​​of the reportConfigType object in the CSI-ReportConfigIE corresponding to the first CSI report and the second CSI report are different or the same. For example, the CSI reporting type of the first CSI report can be periodic, and the CSI reporting type of the second CSI report can be aperiodic. Alternatively, the CSI reporting type of the first CSI report and the second CSI report can both be semi-continuous.

[0350] Furthermore, when the CSI reporting type corresponding to the first CSI report and the second CSI report is periodic or semi-continuous, the reporting periods corresponding to the first CSI report and the second CSI report are different, and the starting offsets of the reporting periods corresponding to the first CSI report and the second CSI report may be different or the same. In other words, the values ​​of the CSI-ReportPeriodicityAndOffset object in the CSI-ReportConfigIE corresponding to the first CSI report and the second CSI report are different, but the object values ​​contained therein for indicating the starting offset may be the same or different. For example, the reporting period of the first CSI report may be 50ms, and the starting offset may be 5ms. The reporting period of the second CSI report may be 5ms, and the starting offset may be 1ms.

[0351] It should be noted that the above description only exemplifies that some configuration items corresponding to the first CSI report and the second CSI report are different. In actual implementation, some other configuration items corresponding to the first CSI report and the second CSI report may also be the same or different, and no specific limitation is imposed here.

[0352] In the above implementation, some configuration items corresponding to the first CSI report and the second CSI report may be the same or different, which can ensure that the two CSI reports and CSI resource configurations can be more flexible, and can improve the applicability and practicality of the channel state information reporting method provided in this application.

[0353] In the method provided in this embodiment, a terminal device reports a first set of joint space-frequency vectors and at least one of the first set of spatial domain vectors and the first set of frequency domain vectors to a network device via a first CSI, and reports a first weighting coefficient corresponding to the first set of joint space-frequency vectors via a second CSI. On the one hand, because the first set of joint space-frequency vectors is determined based on a second matrix obtained by vector sampling from the first matrix, compared to the prior art method of directly obtaining a set of joint space-frequency vectors based on the first matrix, the reported first set of joint space-frequency vectors in the scheme of this application is less complex, the corresponding indication information occupies less overhead, and similarly, the corresponding weighting coefficient occupies less overhead. Therefore, the CSI reporting method provided in this application has low complexity and low overhead. On the other hand, because the first CSI reports at least one of the first set of joint space-frequency vectors and the first set of spatial domain vectors and the first set of frequency domain vectors, the scheme provided in this application can still ensure the accuracy of CSI reporting. Therefore, the CSI reporting method provided in this application can reduce the complexity and overhead of CSI reporting while ensuring the accuracy of CSI reporting. Therefore, by adopting the technical solution provided in this application, the problem of high complexity and high overhead of CSI reporting in the existing technology can be solved, which is conducive to the rational use of communication resources.

[0354] Example 2

[0355] To address the above technical issues, the present application provides another channel state information (CSI) reporting method. In this method, a terminal device reports a first set of space-frequency joint vectors and at least one of the following: a first set of time-space domain vectors, a first set of time-frequency domain vectors, a first set of frequency domain vectors, and a first set of space domain vectors to a network device via a first CSI. The terminal device may also report a first weighting coefficient corresponding to the first set of space-frequency joint vectors via a second CSI. On the one hand, since the first set of space-frequency joint vectors is determined based on a second matrix obtained by vector sampling from the first matrix, compared to the space-frequency joint vector set directly obtained based on the first matrix in the prior art, the first set of space-frequency joint vectors reported in the present application scheme is less complex, the corresponding indication information occupies less overhead, and similarly, the corresponding weighting coefficient occupies less overhead. Therefore, the CSI reporting method provided in the present application has low complexity and low overhead. On the other hand, since the first CSI reports the first set of space-frequency joint vectors, the scheme provided in the present application can still ensure the accuracy of CSI reporting. Therefore, the CSI reporting method provided by this application can reduce the complexity and overhead of CSI reporting while ensuring the accuracy of CSI reporting. Therefore, the technical solution provided by this application can solve the problems of high complexity and high overhead of CSI reporting in the existing technology, and is conducive to the rational use of communication resources.

[0356] See Figure 4 , Figure 4 This is another flow chart of a channel state information CSI reporting method provided by this application. It should be understood that this embodiment will use network equipment and terminal equipment as a method to illustrate the channel state information CSI reporting method provided by this application. This is an example and not a limitation. The execution subject of the channel state information CSI reporting method provided by this application can also be a chip, chip system, or processor applied to the terminal equipment and network equipment, and this application does not impose specific restrictions on this. Figure 4 As shown, the channel state information CSI reporting method may include the following steps:

[0357] S410: The network device sends a target first CSI-RS to the terminal device. Correspondingly, the terminal device receives the first CSI-RS.

[0358] In some feasible implementations, the network device can generate a target first channel state information reference signal CSI-RS and send the target first CSI-RS to the terminal device on the corresponding time-frequency resources. Correspondingly, the terminal device will also receive the target first CSI-RS from the network device on the time-frequency resources. Among them, the target first CSI-RS is mainly used for the terminal device to feedback the first CSI. It should be understood that in actual implementation, the network device will send corresponding CSI reporting configuration information (such as CSI-ReportConfig) to the terminal device, and the terminal device can perform CSI reporting based on the CSI reporting configuration information to send the above-mentioned first CSI. This CSI reporting configuration information contains the configuration information of the target first CSI-RS, and the time-frequency resources for transmitting the target first CSI-RS are indicated by the configuration information of the target first CSI-RS.

[0359] S411: The terminal device determines first CSI, where the first CSI includes first indication information of a first joint space-frequency vector set, and at least one of the following: fifth indication information of a first space-time domain vector set, sixth indication information of a first time-frequency domain vector set, third indication information of a first frequency-domain vector set, and second indication information of the first space-domain vector set.

[0360] In some feasible implementations, after receiving the target first CSI-RS, the terminal device may determine and obtain the first CSI based on the target first CSI-RS. The first CSI may include first indication information of a first joint space-frequency vector set. The first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling of the first matrix. The first matrix is ​​determined based on the first CSI-RS. For example, the first matrix may be determined based on the measurement results of the first CSI-RS. Furthermore, the first CSI also includes at least one of the following: fifth indication information of a first space-time domain vector set, sixth indication information of a first time-frequency domain vector set, third indication information of a first frequency domain vector set, and second indication information of the first space-domain vector set. Both the first space-domain vector set and the first frequency-domain vector set may be determined based on the first matrix. The first space-time domain vector set and the first time-frequency domain vector set are determined based on at least two first statistical information matrices. Any first statistical information matrix of the at least two first statistical information matrices (here, assumed to be matrix J) is determined based on the measurement results of N first CSI-RSs continuously received by the terminal device. N is a positive integer greater than or equal to 2. It should be understood that these N first CSI-RSs may include the target first CSI-RS, or may not include the target first CSI-RS. It can also be understood that the first CSI includes the first indication information, and the first CSI also includes at least one of the fifth indication information, the sixth indication information, the third indication information, and the second indication information. Among them, the first indication information is used to indicate the first space-frequency joint vector set, the fifth indication information is used to indicate the first time-space domain vector set, the sixth indication information is used to indicate the first time-frequency domain vector set, the third indication information is used to indicate the first frequency domain vector set, and the second indication information is used to indicate the first space domain vector set.

[0361] It should be noted that, in actual implementation, the above-mentioned first matrix can be a precoding matrix corresponding to a certain terminal antenna port or a channel matrix corresponding to a certain stream / layer (i.e., stream / layer) determined by the terminal device based on the measurement result of the above-mentioned target first CSI-RS. It should be understood that the terminal device usually reports the channel matrices corresponding to multiple terminal antenna ports together. Since the method provided in this application is similar for the channel matrix corresponding to each terminal antenna port, the embodiment of this application will take the case of reporting the channel matrix corresponding to a certain terminal antenna port as an example. In addition, in the case where the first matrix is ​​a precoding matrix or a channel matrix, the first weighting coefficient mentioned later should also be used by the network device to determine the channel matrix or precoding matrix reported by the terminal device.

[0362] Here, for the description of the matrix dimension and the matrix vector sampling, please refer to the corresponding description in the above embodiment 1, and will not be repeated here.

[0363] In this embodiment, the first matrix may correspond to the first antenna port set and the first frequency domain unit set. The first antenna port set includes multiple antenna ports corresponding to the target first CSI-RS, and the first frequency domain unit set includes multiple frequency domain units occupied by the target first CSI-RS. In addition, the number of rows of the first matrix may be equal to the number of first antenna ports included in the first antenna port set, and the number of columns of the first matrix may be equal to the number of first frequency domain units included in the first frequency domain unit set. For convenience of explanation, in this embodiment, it is assumed that the first antenna port set may specifically include m first antenna ports, namely antenna port s1, antenna port s2, antenna port s3 to antenna port sm. It is assumed that the first frequency domain unit set may include p first frequency domain units, namely frequency domain unit f1, frequency domain unit f2 to frequency domain unit fp. Wherein, m and p are positive integers greater than or equal to 2.

[0364] Since there are multiple implementation methods for the above-mentioned first CSI, for ease of understanding, the following will describe the process of the terminal device determining the first CSI in multiple scenarios.

[0365] Scenario 2.1.1:

[0366] In this scenario, the first CSI may include the first indication information and the fifth indication information. In this case, the first matrix may correspond to the first antenna port set and the first frequency domain unit set, and the second matrix may correspond to the second antenna port set and the first frequency domain unit set. Moreover, the second antenna port set is a subset of the first antenna port set. Among them, the first antenna port set includes multiple antenna ports corresponding to the first CSI-RS, and the first frequency domain unit set includes multiple frequency domain units occupied by the target first CSI-RS. It can also be understood that the second matrix is ​​obtained by the terminal device sampling the vector of the spatial dimension of the first matrix.

[0367] In a specific implementation, after receiving the target first CSI-RS, the terminal device can obtain the measurement result of the target first CSI-RS and determine the first matrix according to the measurement result of the target first CSI-RS.

[0368] Furthermore, the terminal device may perform vector sampling on the first matrix to obtain the second matrix. Here, the specific process of the terminal device performing vector sampling on the first matrix to obtain the second matrix can be referred to the corresponding process described in Scenario 1.1.1 of the above embodiment 1, and will not be repeated here.

[0369] Furthermore, after obtaining the second matrix, the terminal device can determine the first set of space-frequency joint vectors based on the second matrix. The specific process of the terminal device determining the first set of space-frequency joint vectors based on the second matrix can be found in the corresponding process described in Scenario 1.1.1 of Example 1 above, and will not be repeated here.

[0370] Furthermore, the terminal device can also obtain at least two first statistical information matrices stored therein.

[0371] Optionally, each of the at least two first statistical information matrices can be determined by the terminal device based on N first CSI-RSs continuously received by the terminal device. The specific process of determining each first statistical information matrix by the terminal device is described below using any one first statistical information matrix J of the at least two first statistical information matrices as an example.

[0372] Exemplarily, for each N first CSI-RSs received consecutively by the terminal device, N eighth matrices can be determined based on the measurement results of the N first CSI-RSs. Wherein, each eighth matrix corresponds to the above-mentioned first antenna port set and the first frequency domain unit set. Optionally, these N eighth matrices can be N channel matrices corresponding to a certain antenna port of the terminal device at N moments, or N precoding matrices corresponding to a certain stream at N moments. Then, the terminal device can form a seventh matrix based on these N eighth matrices. Specifically, the terminal device can arrange these N eighth matrices together in the spatial dimension to form the above-mentioned seventh matrix. For example, assuming that the above-mentioned N eighth matrices are matrix H1, matrix H2 to matrix HN, the seventh matrix (here assumed to be Hr) can satisfy the following formula (9):

[0373]

[0374] In this case, the seventh matrix corresponds to N first antenna port sets and one first frequency domain unit set. The number of rows of the seventh matrix is ​​N*m, and the number of columns is p.

[0375] Furthermore, the terminal device may determine the spatiotemporal statistical covariance matrix of the seventh matrix, and determine the spatiotemporal statistical covariance matrix of the seventh matrix as the first statistical information matrix J. Here, the number of rows and columns of the first statistical information matrix J are both N*m. Here, the spatiotemporal statistical covariance matrix of the seventh matrix may satisfy the following formula (10):

[0376] Ht=Hr×(Hr) H (10)

[0377] Wherein, Ht is the spatiotemporal statistical covariance matrix of the seventh matrix.

[0378] It should be noted that, in actual implementation, the N first CSI-RSs used to determine each of the above statistical information matrices may be different. That is, after the terminal device continuously receives N first CSI-RSs, it may determine a first statistical information matrix based on the measurement results of the N first CSI-RSs. Then, after the terminal device continues to receive new N first CSI-RSs, it may determine a new first statistical information matrix based on the measurement results of the new N second CSI-RSs. Alternatively, the N first CSI-RSs used to determine any two first statistical information matrices may be partially the same. For example, assuming that the terminal device continuously receives 10 first CSI-RSs, it may first determine a first statistical information matrix based on the 10 first CSI-RSs. Then, after the terminal device continuously receives 5 first CSI-RSs, it may determine a new first statistical information matrix based on the measurement results of the 5 first CSI-RSs and the measurement results of 5 first CSI-RSs out of the 10 first CSI-RSs received previously.

[0379] It should also be noted that because the terminal device continuously receives the first CSI-RS, a large number of first statistical information matrices may be generated. To avoid data redundancy, assuming that the terminal device only needs to use X first statistical information matrices, the terminal device may only store X first statistical information matrices. Where X is a positive integer greater than or equal to 2. If the number of first statistical information matrices accumulated by the terminal device is greater than X, the terminal device may only save the X first statistical information matrices it has most recently determined.

[0380] Furthermore, the terminal device may determine the first spatiotemporal domain vector set based on the at least two first statistical information matrices.

[0381] Exemplarily, the terminal device may calculate the mean of the at least two first statistical information matrices and determine the mean as the second statistical information matrix. Then, the terminal device may determine the above-mentioned first time-space domain vector set based on the second statistical information matrix. Specifically, the terminal device may perform eigenvector extraction on the second statistical information matrix to obtain the above-mentioned first time-space domain vector set. Specifically, the terminal device may first determine the P4 elements with the largest values ​​from the second statistical information matrix. Here, P4 is a positive integer greater than or equal to 1. Then, the terminal device may extract the column vectors where the P4 elements are located and form the above-mentioned first time-space domain vector set. In this case, the first time-space domain vector set may correspond to N first antenna port sets. In addition, the number of rows of the first time-space domain vector set may be equal to N*m, and the number of columns may be equal to P4.

[0382] Alternatively, the terminal device may store only one first statistical information matrix (for the sake of convenience, the description will be replaced by the average statistical information matrix below). For example, after obtaining the first first statistical information matrix and the second first statistical information matrix, the terminal device may calculate the first mean of the first first statistical information matrix and the second first statistical information matrix, and determine the first mean as the value of the average statistical information matrix. Then, each time the terminal device obtains a new first statistical information matrix, it will calculate the second mean of the new first statistical information matrix and the average statistical information matrix, and use the second mean as the new average statistical information matrix, thereby completing the update of the average statistical information matrix. The terminal device will repeat this operation, thereby continuously updating the average statistical information matrix. Furthermore, when the terminal device needs to determine the above-mentioned first spatiotemporal domain vector set, the terminal device can obtain the average statistical information matrix stored at the current moment, and determine the first spatiotemporal domain vector set based on the average statistical information matrix. The specific process can be found in the process described above for the terminal device to determine the above-mentioned first spatiotemporal domain vector set based on the second statistical information matrix, which will not be repeated here.

[0383] It should be noted that the parameter N may be indicated by fourth information provided by the network device. That is, the network device may send the fourth information to the terminal device so that the terminal device can determine the parameter N based on the fourth information.

[0384] Furthermore, after determining the above-mentioned first spatial domain joint vector set and the first time-space domain vector set, the terminal device can determine the first indication information corresponding to the first space-frequency joint vector set and the fifth indication information corresponding to the first time-space domain vector set, and then generate the first CSI containing the above-mentioned first indication information and the fifth indication information.

[0385] In some optional implementations, the first indication information specifically includes first sub-indication information of the first common vector subset and second sub-indication information of the second weighting coefficient. Here, the first common vector subset and the second weighting coefficient may be used to determine the first set of joint space-frequency vectors. Furthermore, the first sub-indication information may be used to indicate the first common vector subset from the entire set of first common vectors.

[0386] It should be explained that in actual implementation, considering issues such as overhead, the first space-frequency joint vector set can be specifically indicated by a common vector set (i.e., the first common vector subset mentioned above) and a set of weighting coefficients (i.e., the second weighting coefficient mentioned above). This second weighting coefficient is the weighting coefficient obtained by projecting or mapping the first space-frequency joint vector set onto the first common vector subset. Therefore, the second weighting coefficient and the first common vector subset can be used by the network device to determine the above-mentioned first space-frequency joint vector set. It can also be understood that the first space-frequency joint vector set is equal to the product of the first common vector set and the second weighting coefficient.

[0387] It should also be noted that the first complete set of common vectors may specifically be composed of multiple vectors known to the network device and the terminal device, and the first sub-indication information may be the index of each common vector included in the first complete set of common vectors. The second sub-indication information may be the amplitude information and phase information of the second weighting coefficient.

[0388] Optionally, each common vector in the first set of common vectors may be obtained by using a two-dimensional discrete Fourier transform vector (also expressed as a 2D-DFT vector) and a DFT vector through a Kronecker product.

[0389] Similarly, the fifth indication information may also include third sub-indication information of the second common vector subset and fourth sub-indication information of the third weighting coefficient. The second common vector subset and the third weighting coefficient may be used to determine the first set of spatiotemporal vectors. Furthermore, the third sub-indication information may be used to indicate the second common vector subset from the entire set of second common vectors. Optionally, each common vector in the entire set of second common vectors may be obtained by using a Kronecker product between a 2D-DFT vector and a DFT vector.

[0390] In the above implementation, when only vector extraction of the spatial dimension of the first matrix is ​​performed, the network device does not need to use other statistical bases except the first space-frequency joint vector set and the first time-space domain vector set when reconstructing the matrix. Therefore, the first CSI only needs to report the first space-frequency joint vector set and the first time-space domain set. This can also avoid the waste of communication resources caused by reporting invalid statistical bases.

[0391] Scenario 2.1.2:

[0392] In this scenario, the first CSI may include the first indication information and the sixth indication information. In this case, the first matrix may correspond to the first antenna port set and the first frequency domain unit set, while the second matrix may correspond to the first antenna port set and the second frequency domain unit set. Furthermore, the second frequency domain unit set is a subset of the first frequency domain unit set. It can also be understood that the second matrix is ​​obtained by the terminal device sampling the vector of the frequency domain dimension of the first matrix.

[0393] In a specific implementation, the terminal device may first determine the first matrix based on the measurement results of the target first CSI-RS. The terminal device may then perform vector sampling on the first matrix to obtain the second matrix. The specific process of the terminal device performing vector sampling on the first matrix to obtain the second matrix can be found in the corresponding description in Scenario 1.1.2 of the first embodiment above and will not be repeated here.

[0394] Furthermore, after obtaining the second matrix, the terminal device can determine the first space-frequency joint vector set according to the second matrix. The specific process can be found in the corresponding process described in the above scenario 2.1.1, which will not be repeated here.

[0395] Furthermore, the terminal device can also obtain at least two first statistical information matrices stored therein.

[0396] Optionally, each of the at least two first statistical information matrices can be determined by the terminal device based on measurement results of N first CSI-RSs continuously received by the terminal device. The specific process of determining each first statistical information matrix by the terminal device is described below using any one first statistical information matrix J of the at least two first statistical information matrices as an example.

[0397] In a specific implementation, for each N first CSI-RSs continuously received by the terminal device, N eighth matrices can be determined based on the measurement results of the N first CSI-RSs. Among them, each eighth matrix corresponds to the above-mentioned first antenna port set and the first frequency domain unit set. Optionally, these N eighth matrices can be N channel matrices corresponding to a certain antenna port of the terminal device at N moments, or N precoding matrices corresponding to a certain stream at N moments. Then, the terminal device can form a seventh matrix based on these N eighth matrices. Specifically, the terminal device can arrange these N eighth matrices together in the frequency domain dimension to form the above-mentioned seventh matrix. For example, assuming that the above-mentioned N eighth matrices are matrix H1, matrix H2 to matrix HN, the seventh matrix (here assumed to be Hr) can satisfy the following formula (11):

[0398] Hr=(H1,H2,…,HN)(11)

[0399] In this case, the seventh matrix corresponds to one first antenna port set and N first frequency domain unit sets. That is, the seventh matrix has m rows and N*p columns.

[0400] Furthermore, the terminal device may determine the time-frequency domain statistical covariance matrix of the seventh matrix, and determine the time-frequency domain statistical covariance matrix of the seventh matrix as the above-mentioned first statistical information matrix J. Here, the number of rows and columns of the first statistical information matrix J are both N*p. Here, the time-frequency domain statistical covariance matrix of the seventh matrix may satisfy the following formula (12):

[0401] Hf=(Hr) H ×Hr (12)

[0402] Wherein, Ht is the time-frequency domain statistical covariance matrix of the seventh matrix.

[0403] Here, for the description of the at least two first statistical information matrices, please refer to the corresponding description in the above scenario 2.1.1, and will not be repeated here.

[0404] Furthermore, the terminal device may determine the first time-frequency domain vector set based on the at least two first statistical information matrices.

[0405] Exemplarily, the terminal device may calculate the mean of the at least two first statistical information matrices and determine the mean as the second statistical information matrix. Then, the terminal device may determine the above-mentioned first time-space domain vector set based on the second statistical information matrix. Specifically, the terminal device may extract the eigenvectors of the second statistical information matrix to obtain the above-mentioned first time-frequency domain vector set. Specifically, the terminal device may first determine P5 eigenvalues ​​with the largest values ​​from the second statistical information matrix. Here, P5 is a positive integer greater than or equal to 1. Then, the terminal device may extract the eigenvectors corresponding to these P5 eigenvalues ​​and form the above-mentioned first time-frequency domain vector set. In this case, the first time-frequency domain vector set may correspond to N first frequency domain unit sets. In addition, the number of rows of the first time-frequency domain vector set may be equal to N*p, and the number of columns may be equal to P5.

[0406] Furthermore, after determining the above-mentioned first spatial domain joint vector set and the first time-frequency domain vector set, the terminal device can determine the first indication information corresponding to the first spatial-frequency joint vector set and the sixth indication information corresponding to the first time-frequency domain vector set, and then generate the first CSI containing the above-mentioned first indication information and the fifth indication information.

[0407] In some optional implementations, the specific implementation of the above-mentioned first indication information can be found in the corresponding description in the above-mentioned scenario 2.1.1, and will not be repeated here.

[0408] Similarly, the sixth indication information may also include fifth sub-indication information of the third common vector subset and sixth sub-indication information of the fourth weighting coefficient. The third common vector subset and the fourth weighting coefficient may be used to determine the first set of time-frequency domain vectors. Furthermore, the fifth sub-indication information may be used to indicate a third common vector subset from the entire set of third common vectors. Optionally, each common vector in the entire set of third common vectors may be obtained by using a Kronecker product of two DFT vectors.

[0409] In the above implementation, when only vector extraction of the frequency domain dimension is performed on the first matrix, the network device does not need to use other statistical bases except the first space-frequency joint vector set and the first time-frequency domain vector set when reconstructing the matrix, so the first CSI only needs to report the first space-frequency joint vector set and the first time-frequency domain set, which can also avoid the waste of communication resources caused by reporting invalid statistical bases.

[0410] Scenario 2.1.3:

[0411] In this scenario, the first CSI may include first indication information, fifth indication information, and third indication information. In this case, the first matrix may correspond to the first antenna port set and the first frequency domain unit set, while the second matrix may correspond to the second antenna port set and the second frequency domain unit set. Furthermore, the second antenna port set is a subset of the first antenna port set, and the second frequency domain unit set is a subset of the first frequency domain unit set. It can also be understood that the second matrix is ​​obtained by the terminal device sampling the vector of the spatial and frequency domain dimensions of the first matrix.

[0412] In a specific implementation, the terminal device may first determine the first matrix based on the measurement results of the target first CSI-RS. The terminal device may then perform vector sampling on the first matrix to obtain the second matrix. The specific process of the terminal device performing vector sampling on the first matrix to obtain the second matrix can be found in the corresponding description in Scenario 1.1.3 of the first embodiment above and will not be repeated here.

[0413] Furthermore, after obtaining the second matrix, the terminal device can determine the first space-frequency joint vector set according to the second matrix. The specific process can be found in the corresponding process described in the above scenario 2.1.1, which will not be repeated here.

[0414] Furthermore, the terminal device may also obtain at least two first statistical information matrices stored therein and determine the first set of spatiotemporal vectors based on the at least two first statistical information matrices. The specific process of the terminal device determining the at least two first statistical information matrices and determining the first set of spatiotemporal vectors based on the at least two first statistical information matrices can be found in the corresponding description in Scenario 2.1.1 above and will not be repeated here.

[0415] Furthermore, the terminal device can also determine the above-mentioned first frequency domain vector set based on the above-mentioned first matrix. The first frequency domain vector set corresponds to the above-mentioned first frequency domain unit set. In other words, the number of rows of the first frequency domain vector set is equal to p, and the number of columns is equal to P3. Here, the specific process of the terminal device determining the first frequency domain vector set based on the above-mentioned first matrix can be referred to the corresponding process described in scenario 1.1.2 in the above embodiment 1, and will not be repeated here.

[0416] Furthermore, after determining the above-mentioned first spatial domain joint vector set, the first time-space domain vector set and the first frequency domain vector set, the terminal device can determine the first indication information corresponding to the first spatial-frequency joint vector set, the fifth indication information corresponding to the first time-space domain vector set and the third indication information corresponding to the first frequency domain vector set, and then generate the first CSI including the above-mentioned first indication information, fifth indication information and third indication information.

[0417] In some optional implementations, the specific implementation of the first indication information and the fifth indication information can be found in the corresponding description in the above scenario 2.1.1, and will not be repeated here.

[0418] Similarly, the third indication information may also include seventh sub-indication information of the fourth common vector subset and eighth sub-indication information of the fifth weighting coefficient. The fourth common vector subset and the fifth weighting coefficient may be used to determine the first set of frequency-domain vectors. Furthermore, the seventh sub-indication information may be used to indicate the fourth common vector subset from the full set of fourth common vectors. Optionally, each common vector in the full set of fourth common vectors may be a DFT vector.

[0419] Scenario 2.1.4:

[0420] In this scenario, the first CSI may include first indication information, sixth indication information, and second indication information of the first spatial domain vector set. In this case, the first matrix may correspond to the first antenna port set and the first frequency domain unit set, while the second matrix may correspond to the second antenna port set and the second frequency domain unit set. Furthermore, the second antenna port set is a subset of the first antenna port set, and the second frequency domain unit set is a subset of the first frequency domain unit set. It can also be understood that the second matrix is ​​obtained by the terminal device sampling the vector of the spatial domain dimension and the frequency domain dimension of the first matrix.

[0421] In a specific implementation, the terminal device may first determine the first matrix based on the measurement results of the target first CSI-RS. The terminal device may then perform vector sampling on the first matrix to obtain the second matrix. The specific process of the terminal device performing vector sampling on the first matrix to obtain the second matrix can be found in the corresponding description in Scenario 2.1.3 above and will not be repeated here.

[0422] Furthermore, after obtaining the second matrix, the terminal device can determine the first space-frequency joint vector set according to the second matrix. The specific process can be found in the corresponding description in the above scenario 2.1.3, which will not be repeated here.

[0423] Furthermore, the terminal device may also obtain at least two first statistical information matrices stored therein and determine the first set of time-frequency domain vectors based on the at least two first statistical information matrices. The specific process of the terminal device determining the at least two first statistical information matrices and determining the first set of time-frequency domain vectors based on the at least two first statistical information matrices can be found in the corresponding description in Scenario 2.1.2 above and will not be repeated here.

[0424] Furthermore, the terminal device may also determine the first spatial vector set based on the first matrix. The first spatial vector set corresponds to the first antenna port set. In other words, the number of rows of the first spatial vector set is equal to m, and the number of columns is equal to P2. The specific process of the terminal device determining the first spatial vector set based on the first matrix can be found in the corresponding process described under scenario 1.1.1 in the first embodiment above, and will not be repeated here.

[0425] Furthermore, after determining the above-mentioned first spatial domain joint vector set, the first time-frequency domain vector set and the first spatial domain vector set, the terminal device can determine the first indication information corresponding to the first spatial-frequency joint vector set, the sixth indication information corresponding to the first time-frequency domain vector set and the second indication information corresponding to the first spatial domain vector set, and then generate the first CSI containing the above-mentioned first indication information, fifth indication information and second indication information.

[0426] In some optional implementations, the specific implementation of the first indication information and the sixth indication information can be found in the corresponding description in the above scenario 2.1.2, and will not be repeated here.

[0427] Similarly, the second indication information may also include ninth sub-indication information of the fifth common vector subset and tenth sub-indication information of the sixth weighting coefficient. The fifth common vector subset and the sixth weighting coefficient may be used to determine the first spatial vector set. Furthermore, the ninth sub-indication information may be used to indicate the fifth common vector subset from the entire set of fifth common vectors. Optionally, each common vector in the entire set of fifth common vectors may be a 2D-DFT vector.

[0428] S412: The terminal device sends the first CSI to the network device. Correspondingly, the network device receives the first CSI.

[0429] In some feasible implementations, after determining the first CSI, the terminal device may send the first CSI to the network device. Specifically, the terminal device may send the first CSI to the network device based on the first CSI reporting configured by the network device. Accordingly, the network device may receive the first CSI from the terminal device.

[0430] It should be noted that in the channel state information reporting method provided in the present application, the network device will configure two different CSI reports for the terminal device, and these two different CSI reports will correspond to two different CSI reporting configuration information. One CSI report can be used for the terminal device to send the above-mentioned first CSI to the network device. For ease of understanding, this CSI report is expressed as the first CSI report. It should be understood that the first CSI report provided in the present application is mainly used for the terminal device to report a vector set that can be used to characterize the channel matrix or precoding matrix to the network device. Each time the terminal device completes the first CSI report, it reports a vector set to the network device, and this vector set can be used by the network device to recover a channel matrix or precoding matrix. Taking the above-mentioned first CSI as an example, the terminal device sends the above-mentioned first CSI to the network device through a first CSI report, thereby completing the reporting of the first space-frequency joint vector set and at least one of the first space domain vector set, the first frequency domain vector set, the first space domain vector set, and the first frequency domain vector set.

[0431] Another type of CSI reporting can be used by the terminal device to send a second CSI to the network device. For ease of understanding, this type of CSI reporting is referred to as a second CSI reporting. This second CSI reporting will be further explained later.

[0432] It should also be noted that the specific behavior of the first CSI report (reporting method, reporting time, etc.) can be determined by the CSI reporting configuration information corresponding to the first CSI report, and the terminal device can complete each first CSI report according to the CSI reporting configuration information corresponding to the first CSI report.

[0433] S413: The network device sends a second CSI-RS to the terminal device. Correspondingly, the terminal device receives the second CSI-RS.

[0434] In some feasible implementations, the network device may generate a second CSI-RS and send the second CSI-RS to the terminal device on the corresponding time-frequency resources. Correspondingly, the terminal device will also receive the second CSI-RS from the network device on the time-frequency resources. The second CSI-RS can be used for the terminal device to feedback the second CSI. It should be understood that the second CSI-RS and the first CSI-RS mentioned above can be CSI-RS transmitted at different times. The second CSI-RS is mainly used for the terminal device to complete the second CSI report, and the first CSI-RS mentioned above is mainly used for the terminal device to complete the first CSI report. The time-frequency resources for transmitting the second CSI-RS are indicated by the configuration information of the second CSI-RS.

[0435] In an optional implementation, the network device may determine the transmission moment of the second CSI-RS (here assumed to be t1) from the N first moments based on the third information. The third information is mainly used to indicate the transmission moment of the second CSI-RS from the N first moments. It should be understood that the N first moments are the transmission moments of the N second CSI-RSs determined by the network device based on the configuration information of the second CSI-RS. Then, the network device may send the second CSI-RS to the terminal device based on the time-frequency resources of the second CSI-RS only at the moment t1. That is to say, among the transmission moments of the N-1 second CSI-RSs other than the moment t1 among the transmission moments of the N second CSI-RSs, the network device will no longer send the second CSI-RS to the terminal device. It should be understood that the above text is explained by taking the example of the third information indicating the transmission moment of a second CSI-RS from the N first moments. In actual implementation, the third information can also be used to indicate the transmission moments of 2 or more CSI-RS from the above-mentioned N first moments (here it is assumed to be Nx, Nx is a positive integer less than N and greater than 1), so that the network device can send Nx CSI-RS to the terminal device respectively only at the transmission moments of these Nx CSI-RS. Here, the Nx transmission moments should include the transmission moment of the above-mentioned second CSI-RS. Since the network device sends 1 or Nx second CSI-RS, the subsequent operations of the terminal device are the same. Therefore, in order to avoid redundancy, the embodiment of the present application will take the scenario where the network device sends the second CSI-RS to the terminal device only at one of the transmission moments of every N second CSI-RS indicated by the configuration information of the second CSI-RS as an example for explanation.

[0436] Correspondingly, the terminal device can also determine the above-mentioned transmission time t1 from the N first moments indicated by the configuration information of the second CSI-RS based on the above-mentioned third information, and receive the second CSI-RS from the network device only at the transmission time t1. It should be supplemented that, in the case where the network device determines the transmission time of the above-mentioned second CSI-RS based on the third information, the network device can also send the third information to the terminal device. Of course, in the case where the network device determines Nx transmission moments from the N first moments based on the third information, the terminal device can also determine the above-mentioned Nx transmission moments based on the third information, and receive Nx second CSI-RS from the network device only at these Nx transmission moments.

[0437] In the above implementation, because the statistical basis reported by the terminal device includes the first set of space-time domain vectors or the first set of time-frequency domain vectors, the network device can send the second CSI-RS to the terminal device only at some of the N second CSI-RS transmission times indicated by the second CSI-RS configuration information. Correspondingly, the terminal device can also receive the second CSI-RS sent by the network device only at these some transmission times. This can further reduce the overhead of CSI reporting and thereby improve the utilization of communication resources.

[0438] Alternatively, the network device may first determine the transmission times of N second CSI-RSs based on the configuration information of the second CSI-RS. Then, the network device may send N second CSI-RSs to the terminal device at the transmission times of these N second CSI-RSs. Correspondingly, after the terminal device determines the transmission time t1 of the above-mentioned second CSI-RS from the transmission times of these N second CSI-RSs based on the third information, it will only receive the second CSI-RS from the network device at the transmission time t1, and will not receive the second CSI-RS from the network device at the other transmission times.

[0439] Similarly, the third information may also be provided by the network device, or specified in the communication protocol between the network device and the terminal device.

[0440] In another optional implementation, the second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set. That is, the second CSI-RS and the first CSI-RS correspond to the same antenna port set and frequency domain unit set. It can also be understood that the first CSI-RS and the second CSI-RS are the same CSI-RS transmitted at different times, or that the first CSI-RS and the second CSI-RS are the same CSI-RS.

[0441] In another optional implementation, the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the above-mentioned second matrix, and the second CSI-RS corresponds to the same frequency domain unit set as the second matrix. In other words, the second CSI-RS is the sparse first CSI-RS, that is, the second CSI-RS is obtained after the first CSI-RS is sparsed. The antenna port set corresponding to the second CSI-RS is obtained by sampling the antenna port set corresponding to the first CSI-RS, and / or the frequency domain unit set corresponding to the second CSI-RS is obtained by sampling the frequency domain unit set corresponding to the first CSI-RS. Moreover, the sampling method used is the same as the sampling method used for the first matrix described above. It should be noted here that when the network device extracts the antenna port set corresponding to the first CSI-RS in the same way and keeps the identifiers of each extracted antenna port unchanged, the antenna port set corresponding to the second CSI-RS can be the same as the antenna port set corresponding to the second matrix.

[0442] Optionally, in the above scenario 2.1.1, the network device may extract elements corresponding to the second antenna port set from the first CSI-RS to form the above second CSI-RS.

[0443] Optionally, in the above scenario 2.1.2, the network device may extract elements corresponding to the second frequency domain unit set from the first CSI-RS to form the above second CSI-RS.

[0444] Optionally, in the above scenario 2.1.3 or scenario 2.1.4, the network device may extract elements corresponding to the second antenna port set and the second frequency domain unit set from the first CSI-RS to form the above second CSI-RS.

[0445] In some feasible implementations, the terminal device may determine the parameter N based on the fourth information. Optionally, the fourth information may be provided by the network device, or may be specified in a communication protocol between the network device and the terminal device.

[0446] It should be noted that the first CSI-RS and the second CSI-RS have the same quasi-co-location relationship. Alternatively, the first CSI-RS can be quasi-co-located with the second CSI-RS. Alternatively, the first CSI-RS and the second CSI-RS can be configured in the same resource set (i.e., resource set).

[0447] In the above implementation, since the second CSI-RS is sparse, the number of corresponding antenna ports and / or the number of occupied frequency domain units are smaller, so the overhead occupied is smaller, which is more conducive to the rational use of communication resources.

[0448] It should be understood that in actual implementation, step S413 can be executed after step S412 or before step S412. This application does not impose any specific restrictions on the execution sequence of step S412 and step S413. The drawings of this application uniformly illustrate step S413 as being executed after step S412.

[0449] S414, the terminal device determines the second CSI including the fourth indication information corresponding to the first weighting coefficient.

[0450] In some feasible implementations, after receiving the second CSI-RS, the terminal device may determine the second CSI based on the measurement result of the second CSI-RS and the first set of space-frequency joint vectors. The second CSI includes third indication information corresponding to the first weighting coefficient, and the first weighting coefficient may be determined based on the first set of space-frequency joint vectors and the measurement result of the second CSI-RS.

[0451] The following describes the process of determining the second CSI by the terminal device in combination with different implementation methods of the second CSI-RS and scenarios 2.1.1 to 2.1.4 described above.

[0452] Implementation method 2.2.1 of the second CSI-RS:

[0453] In this implementation, the second CSI-RS corresponds to the above-mentioned first antenna port set and the first frequency domain unit set. In this case, the above-mentioned first weighting coefficient can be determined based on the first space-frequency joint vector set and the third matrix. The third matrix is ​​obtained by the terminal device performing vector sampling on the fourth matrix, and the fourth matrix is ​​determined by the terminal device based on the second CSI-RS. For example, the fourth matrix can be determined by the terminal device based on the measurement result of the second CSI-RS. The fourth matrix corresponds to the first antenna port set and the first frequency domain unit set. In other words, the fourth matrix and the second CSI-RS correspond to the same antenna port set and frequency domain unit set. Here, the fourth matrix can be the channel matrix corresponding to a certain terminal antenna port or the precoding matrix corresponding to a certain stream / layer determined by the terminal device based on the measurement result of the second CSI-RS. It should be understood that when the first matrix is ​​a channel matrix, the above-mentioned fourth matrix is ​​the channel matrix. When the first matrix is ​​a precoding matrix, the above-mentioned fourth matrix is ​​the precoding matrix.

[0454] Optionally, in the scenario 2.1.1 described above, after obtaining the measurement result of the second CSI-RS, the terminal device may determine the fourth matrix based on the measurement result of the second CSI-RS. Then, the terminal device may perform vector extraction of the spatial dimension of the fourth matrix based on the first information described above to obtain the third matrix. In this case, the third matrix corresponds to the second antenna port set and the first frequency domain unit set. Here, the specific process of the terminal device performing vector extraction of the spatial dimension of the fourth matrix based on the first information to obtain the third matrix is ​​similar to the process described in step S411 above, in which the terminal device performs vector sampling of the spatial dimension of the first matrix based on the first information to obtain the second matrix. In order to avoid redundancy, it will not be repeated here.

[0455] Furthermore, after obtaining the third matrix, the terminal device may determine the first weighting coefficient based on the third matrix and the first set of joint space-frequency vectors. For example, the terminal device may determine the first weighting coefficient as a weighting coefficient obtained by projecting or mapping the third matrix onto the first set of joint space-frequency vectors. It will be appreciated that the third matrix may be the product of the first set of joint space-frequency vectors and the first weighting coefficient.

[0456] Optionally, in the scenario 2.1.2 described above, after the terminal device determines that it has obtained the above-mentioned fourth matrix, it extracts the vector of the frequency domain dimension of the fourth matrix based on the second information described above to obtain the above-mentioned third matrix. In this case, the third matrix corresponds to the above-mentioned first antenna port set and the second frequency domain unit set. Here, the specific process of the terminal device extracting the vector of the frequency domain dimension of the fourth matrix based on the second information to obtain the third matrix is ​​similar to the process described in step S411 above, in which the terminal device samples the vector of the frequency domain dimension of the first matrix based on the second information to obtain the second matrix. In order to avoid redundancy, it will not be repeated here. After obtaining the above-mentioned third matrix, the terminal device can determine the above-mentioned first weighting coefficient based on the third matrix and the above-mentioned first space-frequency joint vector set. The specific process can be found in the corresponding description above, and it will not be repeated here.

[0457] Optionally, in the scenario 2.1.3 or scenario 2.1.4 described above, after obtaining the above-mentioned fourth matrix, the terminal device may perform vector extraction of the spatial and frequency domain dimensions of the fourth matrix based on the first information and the second information described above to obtain the above-mentioned third matrix. In this case, the third matrix corresponds to the above-mentioned second antenna port set and the second frequency domain unit set. Here, the specific process of the terminal device performing vector extraction of the spatial and frequency domain dimensions of the fourth matrix based on the first information and the second information to obtain the target matrix is ​​similar to the process described in step S411 above, in which the terminal device performs vector sampling of the spatial and frequency domain dimensions of the first matrix based on the first information and the second information to obtain the second matrix. In order to avoid redundancy, it will not be repeated here. After obtaining the above-mentioned fourth matrix, the terminal device can determine the above-mentioned first weighting coefficient based on the fourth matrix and the above-mentioned first space-frequency joint vector set. The specific process can be found in the corresponding description above, and it will not be repeated here.

[0458] Furthermore, after determining the first weighting coefficient, the terminal device may generate fourth indication information corresponding to the first weighting coefficient and generate second CSI including the fourth indication information. Here, the fourth indication information may include amplitude information and phase information of the first weighting coefficient.

[0459] Implementation method 2.2.2 of the second CSI-RS:

[0460] In this implementation, the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same set of frequency domain units.

[0461] Optionally, in the above-mentioned scenario 2.1.1, scenario 2.1.2, scenario 2.1.3 or scenario 2.1.4, after obtaining the measurement result of the second CSI-RS, the terminal device may determine a fourth matrix based on the measurement result of the second CSI-RS. Here, the fourth matrix may be a channel matrix corresponding to a certain terminal antenna port or a precoding matrix corresponding to a certain stream / layer determined by the terminal device based on the measurement result of the second CSI-RS. The fourth matrix corresponds to the same antenna port set and frequency domain unit set as the second CSI-RS. Then, the terminal device can determine the above-mentioned first weighting coefficient based on the fourth matrix and the above-mentioned first space-frequency joint vector set. For example, the terminal device may determine the weighting coefficient obtained by projecting or mapping the fourth matrix on the first space-frequency joint vector set as the above-mentioned first weighting coefficient. It can be understood that the fourth matrix is ​​the product of the first space-frequency joint vector set and the first weighting coefficient.

[0462] Furthermore, after determining the first weighting coefficient, the terminal device may generate fourth indication information corresponding to the first weighting coefficient and generate second CSI including the fourth indication information. Similarly, the fourth indication information may include amplitude information and phase information of the first weighting coefficient.

[0463] S415: The terminal device sends the second CSI to the network device. Correspondingly, the network device receives the second CSI.

[0464] In some feasible implementations, after determining the second CSI, the terminal device may send the second CSI to the network device. Specifically, the terminal device may send the second CSI to the network device based on the second CSI reporting configured by the network device. Accordingly, the network device may receive the second CSI from the terminal device.

[0465] It should be noted that the second CSI reporting provided in this application is mainly used for the terminal device to report the weighted coefficients corresponding to the vector set that can be used to represent the precoding matrix to the network device. Each time the terminal device completes the second CSI reporting, it reports the weighted coefficients corresponding to the first space-frequency joint vector set to the network device. Here, the specific behavior of the second CSI reporting (reporting method, reporting time, etc.) can be determined by the CSI reporting configuration information corresponding to the second CSI reporting. The terminal device can complete each second CSI reporting according to the CSI reporting configuration information corresponding to the second CSI reporting.

[0466] For some possible implementations, see Figure 5 , Figure 5 This is another flow chart of a channel state information CSI reporting method provided by this application. Figure 5 Said method further comprises the following steps:

[0467] S416: The network device determines N sixth matrices corresponding to the N first moments according to the first CSI and the second CSI.

[0468] In some feasible implementations, after receiving the first CSI and the second CSI, the network device may determine N sixth matrices corresponding to the N first moments based on the first CSI and the second CSI. Among them. The first weighting coefficient, the first space-frequency joint vector set, and at least one of the following: the first time-space domain vector set, the first time-frequency domain vector set, the first frequency domain vector set, and the first space domain vector set are used to determine the N sixth matrices corresponding to the N first moments. Optionally, the above-mentioned N first moments include the transmission moment of the above-mentioned second CSI-RS. Optionally, these N first moments can be the transmission moments of the N second CSI-RS indicated by the configuration information of the second CSI-RS.

[0469] In actual implementation, combined with the scenarios 2.1.1, 2.1.2, 2.1.3, 2.1.4 and the two implementation methods of the second CSI-RS described above, the specific process of the network device determining N sixth matrices based on the first CSI and the second CSI may include the following situations.

[0470] Case 2.3.1: The first CSI is implemented as described in Scenario 2.1.1 above, and the second CSI-RS uses the implementation method described in Scenario 2.2.1 above.

[0471] In this case, after obtaining the first CSI and the second CSI, the network device may optionally determine the first joint space-frequency vector set, the first space-time domain vector set and the first weighting coefficient based on the first indication information, the fifth indication information and the fourth indication information.

[0472] Then, the network device may determine a third matrix based on the first weighting coefficient and the first space-frequency joint vector set. Here, the third matrix corresponds to the second antenna port set and the first frequency domain unit set. Specifically, the network device may determine the product of the first weighting coefficient and the first space-frequency joint vector set as the third matrix. The third matrix may be a matrix obtained by vector extraction of the spatial dimension of the fourth matrix. The fourth matrix is ​​the sixth matrix corresponding to the transmission moment of the second CSI-RS in the N sixth matrices, and these N sixth matrices correspond one-to-one to the N first moments.

[0473] Furthermore, the network device may determine the N sixth matrices according to the third matrix, the first time-space domain vector set and the first information.

[0474] Optionally, the network device may first perform vector sampling on the first time-space domain vector set based on the first information and the third information to obtain a second time-space domain vector set. The first time-space domain vector set corresponds to N first antenna port sets and N first moments, and the second time-space domain vector set corresponds to N second antenna port sets and the transmission moment corresponding to the second CSI-RS. For example, the network device may extract the row vectors corresponding to each second antenna port in the second antenna port set at the transmission moment corresponding to the second CSI-RS from the first time-space domain vector set to form the second time-space domain vector set. It should be noted that when the third information is used to indicate Nx first moments from the N first moments, the network device will extract the row vectors corresponding to each second antenna port in the second antenna port set at each first moment in the Nx first moments from the first time-space domain vector set to form the second time-space domain vector set. At this time, the second time-space domain vector set corresponds to N second antenna port sets and Nx first moments. Here, the Nx first moments include the transmission moment of the second CSI-RS.

[0475] The network device may then perform the following spatial domain reconstruction operation on the first vector k1 corresponding to any first frequency domain unit i1 in the first frequency domain unit set in the third matrix: the first vector k1 is processed according to the first time-space domain vector set and the second time-space domain vector set to obtain a second vector k2. The second vector k2 corresponds to the N first antenna port sets and the first frequency domain unit i1, and the second vector K2 also corresponds to the N first moments. The network device may then determine the N sixth matrices based on the multiple second vectors obtained by performing the spatial domain reconstruction operation on the first vector corresponding to each first frequency domain unit in the first frequency domain unit set.

[0476] It can also be understood that the network device can perform the above-mentioned spatial domain reconstruction operation on the first vector corresponding to each first frequency domain unit in the above-mentioned third matrix to obtain the second vector corresponding to each first frequency domain unit. Each second vector corresponds to the above-mentioned N first antenna port sets, N first moments, and a first frequency domain unit. Then, the network device can form a large matrix based on the second vector corresponding to each first frequency domain unit. In this large matrix, the block matrix corresponding to each first antenna port set is a sixth matrix. In other words, by dividing this large matrix into blocks based on the N first antenna port sets, the above-mentioned N sixth matrices can be obtained.

[0477] Among them, the first vector k1, the second vector k2, the first time-space domain vector set and the second time-space domain vector set satisfy the following formula (13):

[0478] k1=ST1×(ST2) +×k2 (13)

[0479] Among them, ST1 is the first time-space domain vector set, ST2 is the second time-space domain vector set, (ST2) + is the pseudo-inverse of the second space-time domain vector set. In actual implementation, the network device can calculate the second vector corresponding to each first frequency domain unit based on the above formula (13).

[0480] Case 2.3.2: The first CSI is implemented as described in Scenario 2.1.1 above, and the second CSI-RS uses the implementation method described in Scenario 2.2.2 above.

[0481] In this case, after obtaining the first CSI and the second CSI, the network device may optionally determine the first joint space-frequency vector set, the first space-time domain vector set and the first weighting coefficient based on the first indication information, the fifth indication information and the fourth indication information.

[0482] The network device may then determine a fourth matrix based on the first weighting coefficients and the first set of joint space-frequency vectors. Here, the fourth matrix corresponds to the second antenna port set and the first set of frequency domain elements. For example, the network device may determine the fourth matrix as the product of the first weighting coefficients and the first set of joint space-frequency vectors.

[0483] Furthermore, the network device can determine the N sixth matrices corresponding to the above-mentioned N first moments based on the fourth matrix, the first time-space domain vector set and the first information. Here, the first information is mainly used to indicate the second antenna port set from the first antenna port set.

[0484] Optionally, the network device may first perform vector sampling on the first spatiotemporal vector set according to the first information and the third information to obtain the second spatiotemporal vector set. The specific process can be found in the corresponding description in the above situation 2.3.1, which will not be repeated here.

[0485] The network device may then perform the following spatial domain reconstruction operation on the third vector k3 corresponding to any first frequency domain unit i1 in the first frequency domain unit set in the fourth matrix: the third vector k3 is processed according to the first time-space domain vector set and the second time-space domain vector set to obtain a fourth vector k4. The fourth vector k4 corresponds to the N first antenna port sets and the first frequency domain unit i1, and the fourth vector k4 also corresponds to the N first moments. The network device may then determine the N sixth matrices based on the multiple fourth vectors obtained by performing the spatial domain reconstruction operation on the third vector corresponding to each first frequency domain unit in the first frequency domain unit set.

[0486] It can also be understood that the network device may perform the above-mentioned spatial domain reconstruction operation on the third vector corresponding to each first frequency domain unit in the above-mentioned fourth matrix to obtain the fourth vector corresponding to each first frequency domain unit. The network device may then construct a large matrix based on the fourth vector corresponding to each first frequency domain unit. In this large matrix, the block matrix corresponding to each first antenna port set is a sixth matrix. In other words, by partitioning this large matrix based on the N first antenna port sets, the above-mentioned N sixth matrices can be obtained.

[0487] Among them, the third vector k3, the fourth vector k4, the first time-space domain vector set and the second time-space domain vector set satisfy the following formula (14):

[0488] k4=ST1×(ST2) + ×k3 (14)

[0489] Among them, ST1 is the first time-space domain vector set, ST2 is the second time-space domain vector set, (ST2) + is the pseudo-inverse of the second space-time domain vector set. In actual implementation, the network device can calculate the fourth vector corresponding to each first frequency domain unit based on the above formula (14).

[0490] Case 2.3.3: The first CSI is implemented as described in Scenario 2.1.2 above, and the second CSI-RS adopts the implementation method described in Scenario 2.2.1 above.

[0491] In this case, after obtaining the first CSI and the second CSI, the network device may optionally determine the first space-frequency joint vector set, the first time-frequency domain vector set and the first weighting coefficient based on the first indication information, the sixth indication information and the fourth indication information.

[0492] Then, the network device can determine a third matrix based on the first weighting coefficient and the first space-frequency joint vector set. Here, the third matrix corresponds to the first antenna port set and the second frequency domain unit set. The third matrix is ​​obtained based on vector sampling of the fourth matrix. The fourth matrix is ​​the sixth matrix corresponding to the transmission moment of the second CSI-RS in the N sixth matrices. The N sixth matrices correspond one-to-one to the N first moments. The fourth matrix is ​​determined based on the measurement result of the second CSI-RS. The fourth matrix corresponds to the first antenna port set and the first frequency domain unit set. For example, the network device can determine the product of the first weighting coefficient and the first space-frequency joint vector set as the above-mentioned third matrix.

[0493] Furthermore, the network device may determine N sixth matrices corresponding to the N first moments according to the third matrix, the first time-space domain vector set, and the second information.

[0494] Optionally, the network device may first perform vector sampling on the above-mentioned first time-frequency domain vector set based on the second information and the third information to obtain a second time-frequency domain vector set. The first time-frequency domain vector set corresponds to N first frequency domain unit sets and N first moments, and the second time-frequency domain vector set corresponds to N second frequency domain unit sets and the transmission moment of the above-mentioned second CSI-RS. Specifically, the network device may extract the row vectors corresponding to each second frequency domain unit in the above-mentioned second frequency domain unit set at the transmission moment of the above-mentioned second CSI-RS in the above-mentioned first time-frequency domain vector set to form the above-mentioned second time-frequency domain vector set. It should be supplemented that, when the third information is used to indicate Nx first moments from these N first moments, the network device will extract the row vectors corresponding to each second frequency domain unit in the above-mentioned second frequency domain unit set at each first moment in the Nx first moments in the first time-frequency domain vector set to form the above-mentioned second time-frequency domain vector set. At this time, the above-mentioned second time-frequency domain vector set corresponds to N second frequency domain units and Nx first moments. Here, the Nx first moments include the transmission moment of the second CSI-RS.

[0495] Then, the network device may perform the following frequency domain reconstruction operation on the fifth vector k5 corresponding to any first antenna port i2 in the first antenna port set in the third matrix: the fifth vector k5 is processed according to the first time-frequency domain vector set and the second time-frequency domain vector set to obtain a sixth vector k6. The sixth vector k6 corresponds to the first antenna port i2, N first frequency domain unit sets, and N first moments. Based on the multiple sixth vectors obtained by performing the frequency domain reconstruction operation on the fifth vector corresponding to each first antenna port in the first antenna port set, N sixth matrices are determined. Then, the network device may determine the above-mentioned N sixth matrices based on the multiple sixth vectors obtained by performing the above-mentioned frequency domain reconstruction operation on the fifth vector corresponding to each first antenna port in the first antenna port set.

[0496] It can also be understood that the network device can perform the above-mentioned frequency domain reconstruction operation on the fifth vector corresponding to each first antenna port in the above-mentioned third matrix to obtain the sixth vector corresponding to each first antenna port. The network device can then construct a large matrix based on the sixth vector corresponding to each first frequency domain unit. In this large matrix, the block matrix corresponding to each first frequency domain unit set is a sixth matrix. In other words, by partitioning this large matrix based on N first frequency domain unit sets, the above-mentioned N sixth matrices can be obtained.

[0497] Among them, the fifth vector k5, the sixth vector k6, the first time-frequency domain vector set and the second time-frequency domain vector set satisfy the following formula (15):

[0498] k6=FT1×(FT2) +×k5 (15)

[0499] Among them, FT1 is the first time-frequency domain vector set, FT2 is the second time-frequency domain vector set, (FT2) + is the pseudo-inverse of the second time-frequency domain vector set. In actual implementation, the network device can calculate the sixth vector corresponding to each first frequency domain unit based on the above formula (15).

[0500] Case 2.3.4: The first CSI is implemented as described in Scenario 2.1.2 above, and the second CSI-RS uses the implementation method described in Scenario 2.2.2 above.

[0501] In this case, after obtaining the first CSI and the second CSI, the network device may optionally determine the first space-frequency joint vector set, the first time-frequency domain vector set and the first weighting coefficient based on the first indication information, the sixth indication information and the fourth indication information.

[0502] The network device may then determine a fourth matrix based on the first weighting coefficients and the first set of joint space-frequency vectors. Here, the fourth matrix corresponds to the first set of antenna ports and the second set of frequency domain units. Specifically, the network device may determine the fourth matrix as the product of the first weighting coefficients and the first set of joint space-frequency vectors.

[0503] Furthermore, the network device may determine N sixth matrices corresponding to the N first moments according to the fourth matrix, the first time-space domain vector set, and the second information.

[0504] Optionally, the network device may first perform vector sampling on the first time-frequency domain vector set according to the second information and the third information to obtain a second time-frequency domain vector set. The specific process can be found in the corresponding description in the above situation 2.3.3, which will not be repeated here.

[0505] Then, the network device may perform the following frequency domain reconstruction operation on the seventh vector k7 corresponding to any first antenna port i2 in the first antenna port set in the fourth matrix: the seventh vector k7 is processed according to the first time-frequency domain vector set and the second time-frequency domain vector set to obtain an eighth vector k8. The eighth vector k8 corresponds to the first antenna port i2, N first frequency domain unit sets, and N first moments. N sixth matrices are determined based on multiple eighth vectors obtained by performing the frequency domain reconstruction operation on the seventh vector corresponding to each first antenna port in the first antenna port set. Then, the network device may determine the above-mentioned N sixth matrices based on multiple eighth vectors obtained by performing the above-mentioned frequency domain reconstruction operation on the seventh vector corresponding to each first antenna port in the first antenna port set.

[0506] It can also be understood that the network device can perform the above-mentioned frequency domain reconstruction operation on the seventh vector corresponding to each first antenna port in the above-mentioned fourth matrix to obtain the eighth vector corresponding to each first antenna port. The network device can then construct a large matrix based on the eighth vector corresponding to each first frequency domain unit. In this large matrix, the block matrix corresponding to each first frequency domain unit set is a sixth matrix. In other words, by partitioning this large matrix based on N first frequency domain unit sets, the above-mentioned N sixth matrices can be obtained.

[0507] Among them, the seventh vector k7, the eighth vector k8, the first time-frequency domain vector set and the second time-frequency domain vector set satisfy the following formula (16):

[0508] k8=FT1×(FT2) + ×k7 (16)

[0509] Among them, FT1 is the first time-frequency domain vector set, FT2 is the second time-frequency domain vector set, (FT2) + is the pseudo-inverse of the second time-frequency domain vector set. In actual implementation, the network device can calculate the sixth vector corresponding to each first frequency domain unit based on the above formula (16).

[0510] Case 2.3.5: The first CSI is implemented as described in Scenario 2.1.3 above, and the second CSI-RS adopts the implementation method described in Scenario 2.2.1 above.

[0511] In this case, after obtaining the above-mentioned first CSI and second CSI, the network device can optionally determine the above-mentioned first space-frequency joint vector set, first space-frequency vector set, first frequency domain vector set and first weighting coefficient based on the first indication information, fifth indication information, third indication information and fourth indication information.

[0512] The network device may then determine a third matrix based on the first weighting coefficients and the first set of joint space-frequency vectors. Here, the third matrix corresponds to the second set of antenna ports and the second set of frequency-domain units. For example, the network device may determine the third matrix as the product of the first weighting coefficients and the first set of joint space-frequency vectors.

[0513] Furthermore, the network device may determine N sixth matrices corresponding to the N first moments according to the third matrix, the first space-time domain vector set, the first frequency domain vector set, the first information, and the second information.

[0514] Optionally, the network device may first perform vector sampling on the first spatiotemporal vector set according to the first information and the third information to obtain the second spatiotemporal vector set. The specific process can be found in the corresponding process described in the above situation 2.3.1, which will not be repeated here.

[0515] Then, the network device may perform the following spatial domain reconstruction operation on the ninth vector k9 corresponding to any second frequency domain unit i3 in the second frequency domain unit set in the third matrix: the ninth vector k9 is processed according to the first time-space domain vector set and the second time-space domain vector set to obtain the tenth vector k10. The tenth vector k10 corresponds to N first antenna port sets, N first moments, and the second frequency domain unit i3. Then, the network device may determine the first transition matrix based on the multiple tenth vectors obtained by performing the spatial domain reconstruction operation on the ninth vector corresponding to each second frequency domain unit in the second frequency domain unit set. The first transition matrix corresponds to N first antenna port sets, N first moments, and the second frequency domain unit set. It can also be understood that the network device may perform the above-mentioned spatial domain reconstruction operation on the ninth vector corresponding to each second frequency domain unit in the third matrix to obtain the tenth vector corresponding to each second frequency domain unit. Then, the network device may construct the above-mentioned first transition matrix based on the tenth vector corresponding to each second frequency domain unit.

[0516] Then, the network device may perform vector sampling on the first frequency domain vector set according to the second information and the third information to obtain a second frequency domain vector set. For the specific process, please refer to the corresponding process described in the above situation 2.3.3, which will not be repeated here. Then, the network device may perform the following frequency domain reconstruction operation on the eleventh vector k11 corresponding to any first antenna port i2 in the first antenna port set in the first transition matrix and at any first moment in the N first moments: the eleventh vector k11 is processed according to the first frequency domain vector set and the second frequency domain vector set to obtain a twelfth vector k12. Among them, the twelfth vector k12 corresponds to the first antenna port i2, any first moment and the first frequency domain unit set. Then, the network device may determine N sixth matrices based on the multiple twelfth vectors obtained by performing the frequency domain reconstruction operation on the eleventh vector corresponding to each first antenna port at each first moment. That is, when the number of rows of the first transition matrix is ​​equal to N*m and the number of columns is equal to pf, the network device may perform the frequency domain reconstruction operation on each row vector of the first transition matrix to obtain N*m reconstructed row vectors, and each of these N*m reconstructed row vectors corresponds to the first frequency domain element set. The network device may then construct a large matrix based on these N*m column vectors, and the separate matrix corresponding to each first antenna port set in this large matrix is ​​one of the N sixth matrices.

[0517] Optionally, the ninth vector k9, the tenth vector k10, the first time-space domain vector set, and the second time-space domain vector set satisfy the following formula (17):

[0518] k10=ST1×(ST2) + ×k9 (17)

[0519] Among them, ST1 is the first time-space domain vector set, ST2 is the second time-space domain vector set, (ST2) + is the pseudo-inverse of the second spatiotemporal vector set. In actual implementation, the network device can calculate each tenth vector based on the above formula (17).

[0520] Optionally, the eleventh vector k11, the twelfth vector k12, the first frequency domain vector set, and the second frequency domain vector set satisfy the following formula (18):

[0521] k12=F1×(F2) + ×k11 (18)

[0522] Among them, F1 is the first frequency domain vector set, F2 is the second frequency domain vector set, (F2) + is the pseudo-inverse of the second spatiotemporal vector set. In actual implementation, the network device can calculate each twelfth vector based on the above formula (18).

[0523] It should be noted that the above description describes a network device first performing a spatial domain reconstruction operation on the third matrix to obtain a first transition matrix, and then performing a frequency domain reconstruction operation on the first transition matrix to obtain N sixth matrices. In actual implementation, the network device may also first perform a frequency domain reconstruction operation on the third matrix to obtain a transition matrix, and then perform a spatial domain reconstruction operation on this transition matrix to obtain the aforementioned N sixth matrices. Since the specific implementation process of the latter solution is similar to that of the former solution, differing only in the timing of the spatial domain reconstruction operation and the frequency domain reconstruction operation, it will not be described in detail here to avoid redundancy.

[0524] Case 2.3.6: The first CSI is implemented as described in Scenario 2.1.3 above, and the second CSI-RS uses the implementation method described in Scenario 2.2.2 above.

[0525] In this case, after obtaining the above-mentioned first CSI and second CSI, the network device can optionally determine the above-mentioned first space-frequency joint vector set, first space-frequency vector set, first frequency domain vector set and first weighting coefficient based on the first indication information, fifth indication information, third indication information and fourth indication information.

[0526] The network device may then determine a fourth matrix based on the first weighting coefficients and the first set of joint space-frequency vectors. Here, the fourth matrix corresponds to the second set of antenna ports and the second set of frequency domain units. For example, the network device may determine the fourth matrix as the product of the first weighting coefficients and the first set of joint space-frequency vectors.

[0527] Furthermore, the network device may determine N sixth matrices corresponding to the N first moments according to the fourth matrix, the first space-time domain vector set, the first frequency domain vector set, the first information, and the second information.

[0528] Optionally, the network device may first perform vector sampling on the first spatiotemporal vector set according to the first information and the third information to obtain the second spatiotemporal vector set. The specific process is described above and will not be repeated here.

[0529] Then, the network device may perform the following spatial domain reconstruction operation on the thirteenth vector k13 corresponding to any second frequency domain unit i3 in the second frequency domain unit set in the fourth matrix: the thirteenth vector k13 is processed according to the first time-space domain vector set and the second time-space domain vector set to obtain a fourteenth vector k14. The fourteenth vector k14 corresponds to N first antenna port sets, N first moments and the second frequency domain unit i3. Then, the network device may determine a second transition matrix based on multiple fourteenth vectors obtained by performing the spatial domain reconstruction operation on the thirteenth vector corresponding to each second frequency domain unit in the second frequency domain unit set. The second transition matrix corresponds to N first antenna port sets, N first moments and the second frequency domain unit set. That is, the number of rows of the second transition matrix is ​​equal to N*m, and the number of columns is equal to ps.

[0530] Then, the network device may perform vector sampling on the first frequency domain vector set according to the second information and the third information to obtain a second frequency domain vector set. Please refer to the previous text for the specific process, which will not be repeated here. Then, the network device may perform the following frequency domain reconstruction operation on the fifteenth vector k15 corresponding to any first antenna port i2 in the first antenna port set in the second transition matrix and at any first moment in the N first moments: process the fifteenth vector k15 according to the first frequency domain vector set and the second frequency domain vector set to obtain a sixteenth vector k16. Among them, the sixteenth vector k16 corresponds to the first antenna port i2, any first moment and the first frequency domain unit set. Here, the fifteenth vector k15 corresponding to any first antenna port i2 in the second transition matrix and at any first moment in the N first moments is a row vector of the second transition matrix. Then, the network device may determine the N sixth matrices corresponding to the N first moments based on the multiple sixteenth vectors obtained by performing the frequency domain reconstruction operation on the fifteenth vector corresponding to each first antenna port in the first antenna port set at each first moment. That is, the network device may perform the frequency domain reconstruction operation on each row vector of the second transition matrix to obtain N*m reconstructed row vectors, and each of these N*m reconstructed row vectors corresponds to the first frequency domain unit set. The network device may then construct a large matrix based on these N*m column vectors, wherein the block matrix corresponding to a first antenna port set in this large matrix is ​​one of the N sixth matrices.

[0531] Optionally, the thirteenth vector k13, the fourteenth vector k14, the first time-space domain vector set, and the second time-space domain vector set satisfy the following formula (19):

[0532] k14=ST1×(ST2) + ×k13 (19)

[0533] Among them, ST1 is the first time-space domain vector set, ST2 is the second time-space domain vector set, (ST2) + is the pseudo-inverse of the second spatiotemporal vector set. In actual implementation, the network device can calculate each fourteenth vector based on the above formula (19).

[0534] Optionally, the fifteenth vector k15, the sixteenth vector k16, the first frequency domain vector set, and the second frequency domain vector set satisfy the following formula (20):

[0535] k16=F1×(F2) + ×k15 (20)

[0536] Among them, F1 is the first frequency domain vector set, F2 is the second frequency domain vector set, (F2) +is the pseudo-inverse of the second spatiotemporal vector set. In actual implementation, the network device can calculate each sixteenth vector based on the above formula (20).

[0537] It should be noted that the above description describes a network device first performing a spatial domain reconstruction operation on the fourth matrix to obtain a second transition matrix, and then performing a frequency domain reconstruction operation on the second transition matrix to obtain N sixth matrices. In actual implementation, the network device may also first perform a frequency domain reconstruction operation on the fourth matrix to obtain a transition matrix, and then perform a spatial domain reconstruction operation on this transition matrix to obtain the aforementioned N sixth matrices. Since the specific implementation process of the latter solution is similar to that of the former solution, the only difference being the timing of the spatial domain reconstruction operation and the frequency domain reconstruction operation, it will not be described in detail here to avoid redundancy.

[0538] Case 2.3.7: The first CSI is implemented as described in Scenario 2.1.4 above, and the second CSI-RS adopts the implementation method described in Scenario 2.2.1 above.

[0539] In this case, after obtaining the above-mentioned first CSI and second CSI, the network device can determine the first space-frequency joint vector set, the first time-frequency domain vector set, the first space domain vector set and the first weighting coefficient based on the first indication information, the sixth indication information, the second indication information and the fourth indication information.

[0540] Furthermore, the network device may determine a third matrix based on the first weighting coefficient and the first set of space-frequency joint vectors. The third matrix corresponds to the second antenna port set and the second frequency domain unit set. The specific process can be found in the corresponding process described above and will not be repeated here.

[0541] Furthermore, the network device may determine N sixth matrices according to the third matrix, the first time-frequency domain vector set, the first spatial domain vector set, the first information, and the second information.

[0542] Optionally, the network device may first perform vector sampling on the first time-frequency domain vector set according to the second information and the third information to obtain the second time-frequency domain vector set. The specific process can be found in the corresponding process described in the above situation 2.3.3, which will not be repeated here.

[0543] The network device may then perform the following frequency domain reconstruction operation on the seventeenth vector k17 corresponding to any second antenna port i4 in the second antenna port set in the third matrix: the seventeenth vector k17 is processed based on the first time-frequency domain vector set and the second time-frequency domain vector set to obtain an eighteenth vector k18. The eighteenth vector k18 corresponds to N first frequency domain element sets, N first moments, and the second antenna port set i4. The network device may then determine a third transition matrix based on multiple eighteenth vectors obtained by performing the frequency domain reconstruction operation on the seventeenth vector corresponding to each second antenna port in the second antenna port set. The third transition matrix corresponds to N first frequency domain element sets, N first moments, and the second antenna port set. The third transition matrix has ms rows and N*p columns. That is, the network device may perform the frequency domain reconstruction operation on each row...

Claims

1. A method for reporting channel state information (CSI), characterized in that: The method comprises: receiving a first channel state information reference signal CSI-RS from a network device; Sending first channel state information (CSI) to the network device, wherein the first CSI includes first indication information of a first joint space-frequency vector set, and at least one of second indication information of a first spatial domain vector set and third indication information of a first frequency domain vector set, the first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling of the first matrix, the first spatial domain vector set and the first frequency domain vector set are determined based on the first matrix, and the first matrix is ​​determined based on the first CSI-RS; receiving a second CSI-RS from the network device; Sending second CSI to the network device, where the second CSI includes fourth indication information corresponding to a first weighting coefficient, where the first weighting coefficient is determined based on the first space-frequency joint vector set and the second CSI-RS.

2. The method according to claim 1, characterized in that The first CSI includes the first indication information and the second indication information, the first matrix corresponds to a first antenna port set and a first frequency domain unit set, the second matrix corresponds to a second antenna port set and the first frequency domain unit set, the second antenna port set is a subset of the first antenna port set, the first antenna port set includes multiple antenna ports corresponding to the first CSI-RS, and the first frequency domain unit set includes multiple frequency domain units occupied by the first CSI-RS.

3. The method according to claim 2, characterized in that The second matrix is ​​obtained by performing vector sampling on the first matrix based on first information, where the first information is used to indicate the second antenna port set in the first antenna port set.

4. The method according to claim 1, wherein The first CSI includes the first indication information and the third indication information, the first matrix corresponds to a first antenna port set and a first frequency domain unit set, the second matrix corresponds to the first antenna port set and a second frequency domain unit set, the second frequency domain unit set is a subset of the first frequency domain unit set, the first antenna port set includes multiple antenna ports corresponding to the first CSI-RS, and the first frequency domain unit set includes multiple frequency domain units occupied by the first CSI-RS.

5. The method according to claim 4, characterized in that The second matrix is ​​obtained by performing vector sampling on the first matrix based on second information, and the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

6. The method according to any one of claims 2 to 5, characterized in that: The second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set.

7. The method according to claim 6, characterized in that The first weighting coefficient is determined based on the first space-frequency joint vector set and a third matrix, the third matrix is ​​obtained by vector sampling based on a fourth matrix, and the fourth matrix is ​​determined based on the second CSI-RS.

8. The method according to claim 7, characterized in that When the first CSI includes the first indication information and the second indication information, the third matrix corresponds to the second antenna port set and the first frequency domain unit set; When the first CSI includes the first indication information and the third indication information, the third matrix corresponds to the first antenna port set and the second frequency domain unit set.

9. The method according to any one of claims 2 to 5, characterized in that: The number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same frequency domain unit set.

10. The method according to claim 9, characterized in that The first weighting coefficient is determined based on the first space-frequency joint vector set and a fourth matrix, the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix corresponds to the same antenna port set and frequency domain unit set as the second CSI-RS.

11. The method according to claim 9 or 10, wherein the first CSI-RS and the second CSI-RS have the same quasi-co-location relationship, or the first CSI-RS is quasi-co-located with the second CSI-RS.

12. The method according to any one of claims 1 to 11, characterized in that When the CSI reporting type of the first CSI and the second CSI is periodic or semi-persistent, the CSI reporting period of the first CSI is greater than the CSI reporting period of the second CSI.

13. A method for reporting channel state information (CSI), characterized in that: The method comprises: Sending a first channel state information reference signal CSI-RS to a terminal device; Receiving first channel state information CSI from the terminal device, wherein the first CSI includes first indication information of a first joint space-frequency vector set, and at least one of second indication information of a first spatial domain vector set and third indication information of a first frequency domain vector set, the first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling of the first matrix, the first spatial domain vector set and the first frequency domain vector set are determined based on the first matrix, and the first matrix is ​​determined based on the first CSI-RS; Sending a second CSI-RS to the terminal device; Receive second CSI from the terminal device, wherein the second CSI includes fourth indication information corresponding to a first weighting coefficient, and the first weighting coefficient is determined based on the first space-frequency joint vector set and the second CSI-RS.

14. The method according to claim 13, characterized in that The first CSI includes the first indication information and the second indication information, the first matrix corresponds to a first antenna port set and a first frequency domain unit set, the second matrix corresponds to a second antenna port set and the first frequency domain unit set, the second antenna port set is a subset of the first antenna port set, the first antenna port set includes multiple antenna ports corresponding to the first CSI-RS, and the first frequency domain unit set includes multiple frequency domain units occupied by the first CSI-RS.

15. The method according to claim 14, characterized in that The second matrix is ​​obtained by performing vector sampling on the first matrix based on first information, where the first information is used to indicate a second antenna port set in the first antenna port set.

16. The method according to claim 14 or 15, characterized in that The second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set, and the method further includes: Determine the first joint space-frequency vector set, the first spatial domain vector set, and the first weighting coefficient according to the first indication information, the second indication information, and the fourth indication information; Determine a third matrix based on the first weighting coefficient and the first set of space-frequency joint vectors, wherein the third matrix is ​​obtained based on vector sampling of a fourth matrix, the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix corresponds to the first antenna port set and the first frequency domain unit set; The fourth matrix is ​​determined according to the third matrix, the first spatial vector set, and first information, wherein the first information is used to indicate the second antenna port set in the first antenna port set.

17. The method according to claim 14 or 15, characterized in that The number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same set of frequency domain elements, and the method further includes: Determine the first joint space-frequency vector set, the first spatial domain vector set, and the first weighting coefficient according to the first indication information, the second indication information, and the fourth indication information; Determine a fourth matrix according to the first weighting coefficient and the first set of space-frequency joint vectors, wherein the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix and the second CSI-RS correspond to the same antenna port set and frequency domain unit set; A fifth matrix corresponding to the second CSI-RS is determined according to the fourth matrix, the first spatial domain vector set and the first information, wherein the fifth matrix corresponds to the first antenna port set and the first frequency domain unit set, and the first information indicates the second antenna port set in the first antenna port set.

18. The method according to claim 13, characterized in that The first CSI includes the first indication information and the third indication information, the first matrix corresponds to the first antenna port set and the first frequency domain unit set, the second matrix corresponds to the first antenna port set and the second frequency domain unit set, the second frequency domain unit set is a subset of the first frequency domain unit set, the first antenna port set includes multiple antenna ports corresponding to the first CSI-RS, and the first frequency domain unit set includes multiple frequency domain units occupied by the first CSI-RS.

19. The method according to claim 18, characterized in that The second matrix is ​​obtained by performing vector sampling on the first matrix based on second information, and the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

20. The method according to claim 18 or 19, characterized in that The second CSI-RS corresponds to the first antenna port set and the first frequency domain unit set, and the method further includes: Determine the first joint space-frequency vector set, the first frequency-domain vector set, and the first weighting coefficient according to the first indication information, the third indication information, and the fourth indication information; Determine a third matrix based on the first weighting coefficient and the first set of space-frequency joint vectors, wherein the third matrix is ​​obtained based on vector sampling of a fourth matrix, the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix corresponds to the first antenna port set and the first frequency domain unit set; The fourth matrix is ​​determined according to the third matrix, the first frequency domain vector set, and second information, wherein the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

21. The method according to claim 18 or 19, characterized in that The number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix, and the second CSI-RS and the second matrix correspond to the same set of frequency domain elements, and the method further includes: Determine the first joint space-frequency vector set, the first frequency-domain vector set, and the first weighting coefficient according to the first indication information, the third indication information, and the fourth indication information; Determine a fourth matrix according to the first weighting coefficient and the first set of space-frequency joint vectors, wherein the fourth matrix is ​​determined based on the second CSI-RS, and the fourth matrix and the second CSI-RS correspond to the same antenna port set and frequency domain unit set; Determine the fifth matrix corresponding to the second CSI-RS based on the fourth matrix, the first frequency domain vector set and the second information, wherein the fifth matrix corresponds to the first antenna port set and the first frequency domain unit set, and the second information is used to indicate the second frequency domain unit set in the first frequency domain unit set.

22. According to the method according to any one of claims 13-21, when the number of antenna ports corresponding to the second CSI-RS is the same as the number of antenna ports corresponding to the second matrix and the second CSI-RS and the second matrix correspond to the same frequency domain unit set, the first CSI-RS and the second CSI-RS have the same quasi-co-location relationship, or the first CSI-RS is quasi-co-located with the second CSI-RS.

23. The method according to any one of claims 13 to 22, characterized in that When the CSI reporting type of the first CSI and the second CSI is periodic or semi-persistent, the CSI reporting period of the first CSI is greater than the CSI reporting period of the second CSI.

24. A communication device, characterized in that: The communication device includes a transceiver unit and a processing unit; The transceiver unit is configured to receive a first channel state information reference signal CSI-RS from a network device; The processing unit is configured to generate first channel state information (CSI), where the first CSI includes first indication information of a first joint space-frequency vector set, and at least one of second indication information of a first spatial domain vector set and third indication information of a first frequency domain vector set, where the first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling of the first matrix, the first spatial domain vector set and the first frequency domain vector set are determined based on the first matrix, and the first matrix is ​​determined based on the first CSI-RS; The transceiver unit is further configured to send the first CSI to the network device; The transceiver unit is further configured to receive a second CSI-RS from the network device; The processing unit is further configured to generate second CSI, wherein the second CSI includes fourth indication information corresponding to a first weighting coefficient, where the first weighting coefficient is determined based on the first space-frequency joint vector set and the second CSI-RS; The transceiver unit is further configured to send the second CSI to the network device.

25. A communication device, characterized in that: The communication device includes a transceiver unit and a processing unit; The processing unit is configured to generate and trigger the transceiver unit to send a first channel state information reference signal CSI-RS to the terminal device; The transceiver unit is further configured to receive first channel state information CSI from the terminal device, wherein the first CSI includes first indication information of a first joint space-frequency vector set, and at least one of second indication information of a first spatial domain vector set and third indication information of a first frequency domain vector set, the first joint space-frequency vector set is determined based on a second matrix obtained by vector sampling of the first matrix, the first spatial domain vector set and the first frequency domain vector set are determined based on the first matrix, and the first matrix is ​​determined based on the first CSI-RS; The processing unit is further configured to generate and trigger the transceiver unit to send a second CSI-RS to the terminal device; The transceiver unit is also used to receive a second CSI from the terminal device, wherein the second CSI includes fourth indication information corresponding to a first weighting coefficient, and the first weighting coefficient is determined based on the first space-frequency joint vector set and the second CSI-RS.

26. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program. When the computer program is executed, it implements the channel state information CSI reporting method according to any one of claims 1 to 12, or a channel state information CSI reporting method according to any one of claims 13 to 23.

27. A chip, characterized in that: Including processor and interface; The processor is used to read instructions to execute a channel state information reporting method according to any one of claims 1 to 12, or a channel state information CSI reporting method according to any one of claims 13 to 23.

28. A computer program product, wherein a computer is used to execute the method for reporting channel state information (CSI) according to any one of claims 1 to 12, or the method for reporting channel state information (CS) according to any one of claims 13 to 23.

29. A communication device, characterized in that: include: at least one processor and memory; The memory is used to store computer programs; The processor is used to execute the computer program stored in the memory so that the communication device performs a channel state information CSI reporting method according to any one of claims 1 to 12, or a channel state information CSI reporting method according to any one of claims 13 to 23.

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