Communication method and communication apparatus

Abstract

The present application relates to the field of communications, and in particular to a communication method and a communication apparatus. In a large-scale antenna array scenario, the larger the Rayleigh length, the easier it is for a terminal device to be in a region in line with the law of spherical waves. Due to the presence of spherical waves, the phases of signals at different antenna element positions are distorted, so that during precoding, the distance between antenna elements and scatterers, i.e., the distance of a multipath, needs to be taken into account. In the communication method, each spatial domain basis in a spatial domain basis set takes into account both the angle and distance of a multipath; the terminal device determines a first spatial domain basis from the spatial domain basis set; a combination coefficient is determined on the basis of the first spatial domain basis; then a PMI is sent, the PMI comprising an identifier of the first spatial domain basis and the combination coefficient; and a network device determines a precoding matrix on the basis of the PMI. The codebook which is set on the basis of the spatial domain basis set is more in line with the law of spherical waves, and therefore, the communication method can improve the channel estimation accuracy of codebooks in a large-scale antenna array scenario.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on September 28, 2023, with application number 202311290544.1 and application name “Communication Method and Communication Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communications, and in particular to a communication method and a communication device. Background Art

[0003] In multiple-input multiple-output (MIMO) technology, network equipment can use precoding technology to reduce interference between multiple terminal devices and interference between multiple signal streams of the same terminal device, thereby improving signal quality, achieving space division multiplexing, and increasing spectrum utilization.

[0004] The terminal device can determine the precoding matrix adapted to the downlink channel through channel measurement and other methods, and feedback the relevant information of the precoding matrix to the network device through the precoding matrix indicator (PMI). The network device can determine a precoding matrix that is the same as or similar to the precoding matrix determined by the terminal device from the codebook based on the PMI.

[0005] With the development of large-scale antenna arrays, the area of ​​antenna arrays in network devices has continued to grow. Given a constant carrier frequency, the Rayleigh distance increases exponentially with the antenna array area. As the Rayleigh distance increases, terminal devices are more likely to be located in an area that conforms to the laws of spherical waves. Due to the presence of spherical wavefronts, the signal phases at different antenna element positions are distorted, increasing the risk of mismatch in traditional codebooks. For example, the spatial location corresponding to the codebook index provided by the PMI may not match the actual location of the terminal device, resulting in reduced channel estimation accuracy.

[0006] Summary of the Invention

[0007] Embodiments of the present application provide a communication method and a communication device that can improve the channel estimation accuracy of a codebook in a large-scale antenna array scenario.

[0008] In a first aspect, embodiments of the present application provide a communication method, wherein the method may be performed by a terminal device or a chip applied to the terminal device. The method is described below using the terminal device as an example. The method includes: determining a first spatial basis, where the first spatial basis belongs to a spatial basis set, where the spatial basis set includes multiple spatial basis, each of the multiple spatial basis being determined by the angle and distance of a multipath between an antenna array of a network device and a first object; determining a combination coefficient based on the first spatial basis; and transmitting a PMI, where the PMI includes an identifier of the first spatial basis and the combination coefficient.

[0009] As the Rayleigh distance increases, the terminal device is more likely to be in an area that conforms to the law of spherical waves. Due to the presence of the spherical wavefront, the signal phase at different antenna element positions is distorted. Therefore, when performing precoding, it is necessary to consider the distance from the antenna element to the scatterer, that is, the multipath distance. In this embodiment, each spatial basis in the spatial basis set considers both the angle and distance of the multipath, and the codebook set based on this spatial basis set is more consistent with the law of spherical waves. Therefore, the PMI sent by the terminal device, which includes the identifier of the first spatial basis and the combination coefficient, can match the spatial location determined by the network device with the actual location of the terminal device, thereby improving the accuracy of channel estimation.

[0010] Optionally, before determining the first spatial basis, the communication method further includes: determining a maximum value r of the distance between the terminal device and the antenna array. max and the minimum value r min , and the quantized number of bits Δd of the distance between the terminal device and the antenna array; according to r max 、r min and Δd to determine a distance candidate value set; determine an angle candidate value set; and determine a spatial basis set based on the distance candidate value set and the angle candidate value set.

[0011] The spatial basis set is based on the maximum distance r between the terminal device and the antenna array. max and the minimum value r min It is determined that when the distance between the terminal device and the antenna array changes, the spatial basis set also changes accordingly. Therefore, the spatial basis set determined in this embodiment is more adapted to the actual position of the terminal device.

[0012] Optionally, according to r max 、r min and Δd to determine the distance candidate value set, including: according to r max 、r min and Δd determine the distance interval d gap According to r max 、r min and d gapDetermine the distance candidate value set, the maximum distance candidate value of the distance candidate value set is r max , the minimum distance candidate value of the distance candidate value set is r min , the difference between any two distance candidate values ​​in the distance candidate value set is d gap An integer multiple of .

[0013] In this embodiment, the distance interval d between different distance candidate values gap Similarly, the terminal device receives Δd to determine d gap , compared to receiving multiple d gap (or, d gap and distance), this embodiment can reduce signaling complexity.

[0014] Optionally,

[0015] Optionally, before determining the first spatial basis, the communication method further includes: determining a maximum value r of the distance between the terminal device and the antenna array. max and the minimum value r min , and the distance interval d gap According to r max 、r min and d gap Determine the distance candidate value set, the maximum distance candidate value of the distance candidate value set is r max , the minimum distance candidate value of the distance candidate value set is r min , the difference between two adjacent distance candidate values ​​in the distance candidate value set is d gap , d gap There is a correlation relationship between the distance between the terminal device and the antenna array; determining a set of angle candidate values; and determining a spatial basis set based on the distance candidate value set and the angle candidate value set.

[0016] The association relationship is, for example: d gap It is positively correlated with the distance between the terminal device and the antenna array. That is, the greater the distance between the terminal device and the antenna array, the greater the gap The larger the distance between the terminal device and the antenna array, the smaller the distance between the terminal device and the antenna array, d gap The farther the distance between the terminal device and the antenna array, the lower the distance estimation accuracy. Considering the resolution of the distance, d gap Positive correlation with distance can reduce the computational complexity of channel estimation.

[0017] Optionally, r max and r min It is determined based on the timing advance (TA) of the signal between the antenna array and the terminal device.

[0018] Multiplex TA determines r max and r min , there is no need to send a special ranging signal, which can save signaling overhead.

[0019] Optionally, the identifier of the first spatial basis includes: the identifier of the angle basis corresponding to the first spatial basis, and the identifier of the distance basis corresponding to the first spatial basis; the PMI also includes: a bitmap of non-zero coefficients, the number of bits of the bitmap is 2*L*D*M, L is the number of angle basis corresponding to multiple spatial basis, D is the number of distance basis corresponding to multiple spatial basis, and M is the number of frequency domain basis; the oversampling rate of the distance basis corresponding to the first spatial basis.

[0020] Non-zero coefficients are combined coefficients that are not equal to 0. A bitmap with a bit count of 2*L*D*M can accommodate scenarios that include angle basis, range basis, and frequency basis. The oversampling rate of the range basis can be used to expand the number of range basis, and thus the number of spatial basis in the spatial basis set. A larger set of spatial basis allows network equipment to recover a precoding matrix that is closer to the precoding matrix determined by the terminal device, thereby improving channel estimation accuracy.

[0021] Optionally, the antenna array includes a first subarray and a second subarray, and determining the first spatial basis includes: determining the first received data, the second received data, r max 、r min and δ, wherein the first received data is the data from the first subarray, the second received data is the data from the second subarray, r min is the maximum distance between the terminal device and the antenna array, r min is the minimum distance between the terminal device and the antenna array, δ is the distance between the first subarray and the second subarray; the first received data, the second received data, r are processed by dictionary learning. min 、r min and δ, to obtain the angle basis of the first subarray, the distance basis of the first subarray, the angle basis of the second subarray, and the distance basis of the second subarray; wherein the first spatial basis includes: the angle basis of the first subarray and the distance basis of the first subarray; and / or the angle basis of the second subarray and the distance basis of the second subarray.

[0022] Because the codebook in the embodiment of the present application adds a distance dimension, the terminal device faces problems such as increased complexity, increased feedback overhead, and increased power consumption when performing channel estimation. After dividing the antenna array into multiple subarrays, the terminal device can estimate the basis of different subarrays separately, and finally jointly feedback the PMIs of multiple subarrays. The network device can reconstruct the channel based on the geometric relationship between the multiple subarrays and the PMIs of the multiple subarrays. Because the amount of received data that the terminal device needs to process when estimating the basis of a subarray is reduced, the number of times the dictionary learning process performs loop nesting of distance and angle is reduced, thereby reducing the complexity and power consumption of the terminal device's channel estimation.

[0023] Optionally, the first spatial basis includes: an angle basis of the first subarray and a distance basis of the first subarray; the combination coefficient is the combination coefficient of the first subarray, and the PMI also includes an identifier of the frequency domain basis of the first subarray; or, the first spatial basis includes: an angle basis of the second subarray and a distance basis of the second subarray; the combination coefficient is the combination coefficient of the second subarray, and the PMI also includes an identifier of the frequency domain basis of the second subarray.

[0024] Different subarrays can share some parameters. For example, the first subarray and the second subarray can share the frequency domain basis and the combined system. In the first subarray and the second subarray, the spatial domain basis of one subarray can also be derived based on the spatial domain set of the other subarray and the geometric relationship between the two subarrays. Therefore, when sending the PMI, the terminal device can send the identifier of the frequency domain basis, the identifier of the spatial domain basis, and the coefficient of one subarray in the first subarray and the second subarray, thereby reducing the feedback overhead.

[0025] Optionally, before determining the first spatial basis, the communication method further includes: determining a distance d between the terminal device and the antenna array TA According to d TA Determine a target channel model, where the target channel model is a first channel model or a second channel model, wherein, in the first channel model, distances from each vibrator in the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; determine a first spatial basis, including: when the target channel model is the first channel model, determine the first spatial basis.

[0026] Different distances are suitable for different target channel models. The target channel model determined based on the distance between the terminal device and the antenna array can match the actual position of the terminal device and improve the accuracy of channel estimation.

[0027] Optionally, according to d TA Determine the target channel model, including: determining d FF , d FFis the distance from each vibrator in the antenna array to the first object in the second channel model; if d TA with d FF The absolute value of the difference between the two is less than the first distance threshold, and the target channel model is determined to be the first channel model; if d TA with d FF The absolute value of the difference between is greater than the second distance threshold, and the target channel model is determined to be the second channel model; wherein the first distance threshold is less than or equal to the second distance threshold.

[0028] If d TA with d FF The absolute value of the difference is less than the first distance threshold, indicating that the distance between the terminal device and the antenna array is close, the distances between the vibrators in the antenna array and the terminal device vary greatly, and the actual position of the terminal device is more consistent with the first channel model. TA with d FF The absolute value of the difference is greater than the second distance threshold, indicating that the distance between the terminal device and the antenna array is far, and the distances between the vibrators in the antenna array and the terminal device are small and can be considered equal. The actual position of the terminal device is more consistent with the second channel model. TA with d FF The difference can accurately determine the currently applicable channel model and improve the accuracy of channel estimation.

[0029] Optionally, according to d TA Determine the target channel model, including: determining d FF , d FF is the distance from each vibrator in the antenna array to the first object in the second channel model; if d FF with d FF The ratio of is less than the third distance threshold, the target channel model is determined to be the first channel model; if d FF with d FF is greater than a fourth distance threshold, determining that the target channel model is the second channel model; wherein the third distance threshold is less than or equal to the fourth distance threshold.

[0030] If d TA with d FF If the ratio of is less than the third distance threshold, it means that the distance between the terminal device and the antenna array is close, the distances between the oscillators in the antenna array and the terminal device vary greatly, and the actual position of the terminal device is more consistent with the first channel model. TA with d FF If the ratio is greater than the fourth distance threshold, it means that the distance between the terminal device and the antenna array is far, and the distances between the oscillators in the antenna array and the terminal device are relatively small and can be considered equal. The actual position of the terminal device is more consistent with the second channel model. TA with dFF The ratio of can accurately determine the currently applicable channel model and improve the accuracy of channel estimation.

[0031] Optionally, determine the distance d between the terminal device and the antenna array TA , comprising: determining the TA of the first signal; determining d according to the TA of the first signal TA .

[0032] Multiplex TA determines d TA , there is no need to send a special ranging signal, which can save signaling overhead.

[0033] Optionally, the first signal is one of multiple signals; the multiple signals include a random access preamble, a sounding reference signal (SRS) and a demodulation reference signal (DMRS), and the first signal is SRS; or, the multiple signals include a random access preamble and DMRS, and the first signal is DMRS.

[0034] The TA measured by SRS is more accurate than the TA measured by DMRS or random access preamble, and the TA measured by DMRS is more accurate than the TA measured by random access preamble. Therefore, by selecting the first signal based on the above priority, a more accurate TA can be obtained, thereby making the target channel model determined based on TA more accurate.

[0035] Optionally, before determining the TA of the first signal, the communication method further includes: receiving first indication information, where the first indication information is used to indicate the TA; determining the TA of the first signal includes: determining the TA of the first signal according to the first indication information.

[0036] The network device may determine the TA based on the first signal and inform the terminal device of the TA, and the terminal device may determine the TA based on the TA. TA , and then according to d TA Determine the target channel model. Therefore, this embodiment can reuse the existing process (the process of the terminal device obtaining the TA) to determine the target channel model, thereby reducing the overhead of determining the target channel model.

[0037] Optionally, before determining the first spatial basis, the communication method further includes: determining a trace of the spatial correlation matrix of the antenna array. cur According to tra curDetermine a target channel model, where the target channel model is a first channel model or a second channel model, wherein, in the first channel model, distances from each vibrator in the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; determine a first spatial basis, including: when the target channel model is the first channel model, determine the first spatial basis.

[0038] tra cur There is an association relationship between the target channel model and different tra cur Applicable to different target channel models, based on tra cur The determined target channel model can match the actual location of the terminal device and improve the accuracy of channel estimation.

[0039] Optionally, according to tra cur Determine the target channel model, including: determining tra ref ,tra ref is the trace of the spatial correlation matrix corresponding to the second channel model; if tra cur With tra ref The absolute value of the difference between the two is greater than the first trace threshold, and the target channel model is determined to be the first channel model; if tra cur With tra ref The absolute value of the difference between is less than the second trace threshold, and the target channel model is determined to be the second channel model; wherein the first trace threshold is greater than or equal to the second trace threshold.

[0040] If tra cur With tra ref The absolute value of the difference is greater than the first trace threshold, indicating that the distance between the terminal device and the antenna array is relatively close, and the distances between the oscillators in the antenna array and the terminal device vary greatly, and the actual position of the terminal device is more consistent with the first channel model. cur With tra ref The absolute value of the difference is less than the second trace threshold, indicating that the distance between the terminal device and the antenna array is far, and the distances between the oscillators in the antenna array and the terminal device are small and can be considered equal. The actual position of the terminal device is more consistent with the second channel model. cur With tra ref The difference can accurately determine the currently applicable channel model and improve the accuracy of channel estimation.

[0041] Optionally, according to tra cur Determine the target channel model, including: determining tra ref ,tra ref is the trace of the spatial correlation matrix corresponding to the second channel model; if tra cur With traref The ratio of is greater than the third trace threshold, the target channel model is determined to be the first channel model; if tra cur With tra ref is less than the fourth trace threshold, the target channel model is determined to be the second channel model; wherein the third trace threshold is greater than or equal to the fourth trace threshold.

[0042] If tra cur With tra ref If the ratio is greater than the third trace threshold, it means that the distance between the terminal device and the antenna array is close, the distances between the oscillators in the antenna array and the terminal device vary greatly, and the actual position of the terminal device is more consistent with the first channel model. cur With tra ref The ratio of is less than the fourth trace threshold, indicating that the distance between the terminal device and the antenna array is far, and the distances between the oscillators in the antenna array and the terminal device are relatively small and can be considered equal. The actual position of the terminal device is more consistent with the second channel model. cur With tra ref The ratio of can accurately determine the currently applicable channel model and improve the accuracy of channel estimation.

[0043] Optionally, tra ref is the default value, or, ref is the average value of the traces of the spatial correlation matrices of multiple terminal devices to which the second channel model is applied.

[0044] tra ref It can be a value pre-configured by the network device, a value defined by the protocol, an empirical value, or a value measured when the communication network is established. ref In this way, the terminal device receives tra ref The frequency of the transmission is reduced, or the terminal device does not need to receive transmission from the network device. ref , thereby reducing the terminal equipment to determine the tra ref The power consumption of tra is determined by the average value of the trace of the spatial correlation matrix of multiple terminal devices. ref , which can reduce tra ref The error, based on the tra ref The determined target channel model is more accurate.

[0045] Optionally, determine tra ref Before, the communication method further includes: receiving second indication information, the second indication information is used to indicate tra ref ; Determine tra ref , including: determining tra according to the second indication information ref .

[0046] In this embodiment, the terminal device can obtain the latest tra ref , the latest tra ref More compatible with current channel conditions, so based on the latest tra ref The determined target channel model is more accurate.

[0047] Optionally, tra cur is the average of the traces of the spatial correlation matrix of multiple time units.

[0048] The tra is determined by averaging the traces of the spatial correlation matrix over multiple time units. cur , which can reduce tra cur The error, based on the tra cur The determined target channel model is more accurate.

[0049] Optionally, the communication method further includes: sending third indication information, where the third indication information is used to indicate the target channel model.

[0050] After the terminal device determines the target channel model, it can inform the network device of the target channel model through the third indication information, so that the network device can reconstruct a more accurate precoding matrix based on the target channel model.

[0051] Optionally, before determining the first spatial basis, the communication method also includes: receiving fourth indication information, the fourth indication information is used to indicate a target channel model, the target channel model is a first channel model or a second channel model, wherein, in the first channel model, the distances from each vibrator of the antenna array to the first object are not equal, and in the second channel model, the distances from each vibrator in the antenna array to the first object are equal; determining the target channel model according to the fourth indication information; determining the first spatial basis, including: determining the first spatial basis when the target channel model is the first channel model.

[0052] In this embodiment, the terminal device obtains the target channel model from the network device through the fourth indication information, and does not need to determine the target channel model through local calculation, thereby reducing the power consumption of the terminal device in determining the target channel model.

[0053] In a second aspect, an embodiment of the present application provides a communication method, wherein the execution subject of the method may be a network device or a chip applied to the network device. The following description uses the execution subject being the network device as an example. The method includes: receiving a PMI, wherein the PMI includes an identifier of a first spatial basis and a combining coefficient; determining the first spatial basis from a set of spatial basis based on the identifier of the first spatial basis, wherein the set of spatial basis includes multiple spatial basis, each of the multiple spatial basis being determined by the angle and distance of a multipath between an antenna array of the network device and a first object; and determining a precoding matrix based on the first spatial basis and the combining coefficient.

[0054] As the Rayleigh distance increases, the terminal device is more likely to be in an area that conforms to the law of spherical waves. Due to the existence of the spherical wavefront, the signal phase at different locations is distorted. Therefore, when performing precoding, it is necessary to consider the distance from the antenna element to the scatterer, that is, the multipath distance. In this embodiment, each spatial basis in the spatial basis set considers both the angle and distance of the multipath, and the codebook set based on this spatial basis set is more consistent with the law of spherical waves. Therefore, the PMI sent by the terminal device, which includes the identifier of the first spatial basis and the combination coefficient, can match the spatial location determined by the network device with the actual location of the terminal device, thereby improving the accuracy of channel estimation.

[0055] Optionally, before determining the first spatial basis from the set of spatial basis according to the identifier of the first spatial basis, the communication method further includes: determining a maximum value r of the distance between the terminal device and the antenna array. max and the minimum value r min , and the quantized number of bits Δd of the distance between the terminal device and the antenna array; according to r max 、r min and Δd to determine a distance candidate value set; determine an angle candidate value set; and determine a spatial basis set based on the distance candidate value set and the angle candidate value set.

[0056] The spatial basis set is based on the maximum distance r between the terminal device and the antenna array. max and the minimum value r min It is determined that when the distance between the terminal device and the antenna array changes, the spatial basis set also changes accordingly. Therefore, the spatial basis set determined in this embodiment is more adapted to the actual position of the terminal device.

[0057] Optionally, according to r max 、r min and Δd to determine the distance candidate value set, including: according to r max 、r min and Δd determine the distance interval d gap According to r max 、r min and dgap Determine the distance candidate value set, the maximum distance candidate value of the distance candidate value set is r max , the minimum distance candidate value of the distance candidate value set is r min , the difference between any two distance candidate values ​​in the distance candidate value set is d gap An integer multiple of .

[0058] Optionally,

[0059] Optionally, before determining the first spatial basis from the set of spatial basis according to the identifier of the first spatial basis, the communication method further includes: determining a maximum value r of the distance between the terminal device and the antenna array. max and the minimum value r min , and the distance interval d gap According to r max 、r min and d gap Determine the distance candidate value set, the maximum distance candidate value of the distance candidate value set is r max , the minimum distance candidate value of the distance candidate value set is r min , the difference between two adjacent distance candidate values ​​in the distance candidate value set is d gap , d gap There is a correlation relationship between the distance between the terminal device and the antenna array; determining a set of angle candidate values; and determining a spatial basis set based on the distance candidate value set and the angle candidate value set.

[0060] The association relationship is, for example: d gap It is positively correlated with the distance between the terminal device and the antenna array. That is, the greater the distance between the terminal device and the antenna array, the greater the gap The larger the distance between the terminal device and the antenna array, the smaller the distance between the terminal device and the antenna array, d gap The smaller.

[0061] Optionally, r max and r min It is determined based on the TA of the signal between the antenna array and the terminal device.

[0062] Multiplex TA determines r max and r min , there is no need to send a special ranging signal, which can save signaling overhead.

[0063] Optionally, the identifier of the first spatial basis includes: the identifier of the angle basis corresponding to the first spatial basis, and the identifier of the distance basis corresponding to the first spatial basis; the PMI also includes: a bitmap of non-zero coefficients, the number of bits of the bitmap is 2*L*D*M, L is the number of angle basis corresponding to multiple spatial basis, D is the number of distance basis corresponding to multiple spatial basis, and M is the number of frequency domain basis; the oversampling rate of the distance basis corresponding to the first spatial basis.

[0064] Non-zero coefficients are combined coefficients that are not equal to 0. A bitmap with a bit count of 2*L*D*M can accommodate scenarios that include angle basis, range basis, and frequency basis. The oversampling rate can be used to expand the number of range basis, and thus the number of spatial basis sets. A larger set of spatial basis sets helps network devices recover a precoding matrix that is closer to the precoding matrix determined by the terminal device, improving channel estimation accuracy.

[0065] Optionally, the antenna array includes a first subarray and a second subarray, and the first spatial basis includes: the angle basis of the first subarray, and the distance basis of the first subarray; and / or, the angle basis of the second subarray, and the distance basis of the second subarray.

[0066] Different subarrays can share some parameters. For example, the first subarray and the second subarray can share the frequency domain basis and the combined system. In the first subarray and the second subarray, the spatial domain basis of one subarray can also be derived based on the spatial domain set of the other subarray and the geometric relationship between the two subarrays. Therefore, when sending the PMI, the terminal device can send the identifier of the frequency domain basis, the identifier of the spatial domain basis, and the coefficient of one subarray in the first subarray and the second subarray, thereby reducing the feedback overhead.

[0067] Optionally, the first spatial basis includes: an angle basis of the first subarray, and a distance basis of the first subarray; determining the precoding matrix based on the first spatial basis and the combination coefficient includes: determining the angle basis of the second subarray and the distance basis of the second subarray based on the angle basis of the first subarray, the distance basis of the first subarray, and the spacing between the first subarray and the second subarray; determining the precoding matrix based on the angle basis of the first subarray, the distance basis of the first subarray, the angle basis of the second subarray, the distance basis of the second subarray, and the combination coefficient.

[0068] Because the codebook in the embodiment of the present application adds a distance dimension, the terminal device faces problems such as increased complexity, increased feedback overhead, and increased power consumption when performing channel estimation. After dividing the antenna array into multiple subarrays, the terminal device can estimate the basis of different subarrays separately, and finally jointly feedback the PMIs of multiple subarrays. The network device can reconstruct the channel based on the geometric relationship between the multiple subarrays and the PMIs of the multiple subarrays. Because the amount of received data that the terminal device needs to process when estimating the basis of a subarray is reduced, the number of times the dictionary learning process performs loop nesting of distance and angle is reduced, thereby reducing the complexity and power consumption of the terminal device's channel estimation.

[0069] Optionally, before determining the first spatial basis from the set of spatial basis according to the identifier of the first spatial basis, the communication method further includes: determining the distance d between the terminal device and the antenna array. TA According to d TA Determine a target channel model, where the target channel model is a first channel model or a second channel model, wherein, in the first channel model, distances from each vibrator of the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; determine the first spatial basis from the spatial basis set according to the identifier of the first spatial basis, including: when the target channel model is the first channel model, determine the first spatial basis from the spatial basis set according to the identifier of the first spatial basis.

[0070] Different distances are suitable for different target channel models. The target channel model determined based on the distance between the terminal device and the antenna array can match the actual position of the terminal device and improve the accuracy of channel estimation.

[0071] Optionally, according to d TA Determine the target channel model, including: determining d FF , d FF is the distance from each vibrator in the antenna array to the first object in the second channel model; if d TA with d FF The absolute value of the difference between the two is less than the first distance threshold, and the target channel model is determined to be the first channel model; if d TA with d FF The absolute value of the difference between is greater than the second distance threshold, and the target channel model is determined to be the second channel model; wherein the first distance threshold is less than or equal to the second distance threshold.

[0072] If d TA with d FF The absolute value of the difference is less than the first distance threshold, indicating that the distance between the terminal device and the antenna array is close, the distances between the vibrators in the antenna array and the terminal device vary greatly, and the actual position of the terminal device is more consistent with the first channel model.TA with d FF The absolute value of the difference is greater than the second distance threshold, indicating that the distance between the terminal device and the antenna array is far, and the distances between the vibrators in the antenna array and the terminal device are small and can be considered equal. The actual position of the terminal device is more consistent with the second channel model. TA with d FF The difference can accurately determine the currently applicable channel model and improve the accuracy of channel estimation.

[0073] Optionally, according to d TA Determine the target channel model, including: determining d FF , d FF is the distance from each vibrator in the antenna array to the first object in the second channel model; if d TA with d FF The ratio of is less than the third distance threshold, the target channel model is determined to be the first channel model; if d TA with d FF is greater than a fourth distance threshold, determining that the target channel model is the second channel model; wherein the third distance threshold is less than or equal to the fourth distance threshold.

[0074] If d TA with d FF If the ratio of is less than the third distance threshold, it means that the distance between the terminal device and the antenna array is close, the distances between the oscillators in the antenna array and the terminal device vary greatly, and the actual position of the terminal device is more consistent with the first channel model. TA with d FF If the ratio is greater than the fourth distance threshold, it means that the distance between the terminal device and the antenna array is far, and the distances between the oscillators in the antenna array and the terminal device are relatively small and can be considered equal. The actual position of the terminal device is more consistent with the second channel model. TA with d FF The ratio of can accurately determine the currently applicable channel model and improve the accuracy of channel estimation.

[0075] Optionally, determine the distance d between the terminal device and the antenna array TA , comprising: determining the TA of the first signal; determining d according to the TA of the first signal TA .

[0076] Multiplex TA determines d TA , there is no need to send a special ranging signal, which can save signaling overhead.

[0077] Optionally, the first signal is one of multiple signals; the multiple signals include a random access preamble, an SRS, and a DMRS, and the first signal is an SRS; or, the multiple signals include a random access preamble and a DMRS, and the first signal is a DMRS.

[0078] The TA measured by SRS is more accurate than the TA measured by DMRS or random access preamble, and the TA measured by DMRS is more accurate than the TA measured by random access preamble. Therefore, by selecting the first signal based on the above priority, a more accurate TA can be obtained, thereby making the target channel model determined based on TA more accurate.

[0079] Optionally, before determining the first spatial basis from the set of spatial basis according to the identifier of the first spatial basis, the communication method further comprises: determining the trace of the spatial correlation matrix of the antenna array. cur According to tra cur Determine a target channel model, where the target channel model is a first channel model or a second channel model, wherein, in the first channel model, distances from each vibrator of the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; determine the first spatial basis from the spatial basis set according to the identifier of the first spatial basis, including: when the target channel model is the first channel model, determine the first spatial basis from the spatial basis set according to the identifier of the first spatial basis.

[0080] tra cur There is an association relationship between the target channel model and different tra cur Applicable to different target channel models, based on tra cur The determined target channel model can match the actual location of the terminal device and improve the accuracy of channel estimation.

[0081] Optionally, according to tra cur Determine the target channel model, including: determining tra ref ,tra ref is the trace of the spatial correlation matrix corresponding to the second channel model; if tra cur With tra ref The absolute value of the difference between the two is greater than the first trace threshold, and the target channel model is determined to be the first channel model; if tra cur With tra ref The absolute value of the difference between is less than the second trace threshold, and the target channel model is determined to be the second channel model; wherein the first trace threshold is greater than or equal to the second trace threshold.

[0082] If tra cur With tra refThe absolute value of the difference is greater than the first trace threshold, indicating that the distance between the terminal device and the antenna array is relatively close, and the distances between the oscillators in the antenna array and the terminal device vary greatly, and the actual position of the terminal device is more consistent with the first channel model. cur With tra ref The absolute value of the difference is less than the second trace threshold, indicating that the distance between the terminal device and the antenna array is far, and the distances between the oscillators in the antenna array and the terminal device are small and can be considered equal. The actual position of the terminal device is more consistent with the second channel model. TA with d FF The difference can accurately determine the currently applicable channel model and improve the accuracy of channel estimation.

[0083] Optionally, according to tra cur Determine the target channel model, including: determining tra ref ,tra ref is the trace of the spatial correlation matrix corresponding to the second channel model; if tra cur With tra ref The ratio of is greater than the third trace threshold, the target channel model is determined to be the first channel model; if tra cur With tra ref is less than the fourth trace threshold, the target channel model is determined to be the second channel model; wherein the third trace threshold is greater than or equal to the fourth trace threshold.

[0084] If tra cur With tra ref If the ratio is greater than the third trace threshold, it means that the distance between the terminal device and the antenna array is close, the distances between the oscillators in the antenna array and the terminal device vary greatly, and the actual position of the terminal device is more consistent with the first channel model. cur With tra ref The ratio of is less than the fourth trace threshold, indicating that the distance between the terminal device and the antenna array is far, and the distances between the oscillators in the antenna array and the terminal device are relatively small and can be considered equal. The actual position of the terminal device is more consistent with the second channel model. cur With tra ref The ratio of can accurately determine the currently applicable channel model and improve the accuracy of channel estimation.

[0085] Optionally, tra cur is the average of the traces of the spatial correlation matrix of multiple time units.

[0086] The tra is determined by averaging the traces of the spatial correlation matrix over multiple time units. cur , which can reduce tra cur The error, based on the tra curThe determined target channel model is more accurate.

[0087] Optionally, tra ref is the default value, or, ref is the average value of the traces of the spatial correlation matrices of multiple terminal devices to which the second channel model is applied.

[0088] tra ref It can be a value defined by the protocol, a value defined by the protocol, an empirical value, or a value measured when the communication network is established. ref In this way, network devices no longer need to calculate tra ref , thereby reducing the network equipment to determine the tra ref The power consumption of tra is determined by the average value of the trace of the spatial correlation matrix of multiple terminal devices. ref , which can reduce tra ref The error, based on the tra ref The determined target channel model is more accurate.

[0089] Optionally, the communication method further includes: sending fourth indication information, where the fourth indication information is used to indicate the target channel model.

[0090] After the network device determines the target channel model, it indicates the target channel model to the terminal device through the fourth indication information. The terminal device does not need to determine the target channel model through local calculation, thereby reducing the power consumption of the terminal device in determining the target channel model.

[0091] Optionally, before determining the first spatial basis from the spatial basis set according to the identifier of the first spatial basis, the communication method also includes: receiving third indication information, the third indication information is used to indicate the target channel model, the target channel model is the first channel model or the second channel model, wherein, in the first channel model, the distances from each vibrator of the antenna array to the first object are not equal, and in the second channel model, the distances from each vibrator in the antenna array to the first object are equal; determining the target channel model according to the third indication information; determining the first spatial basis from the spatial basis set according to the identifier of the first spatial basis, including: when the target channel model is the first channel model, determining the first spatial basis from the spatial basis set according to the identifier of the first spatial basis.

[0092] After the terminal device determines the target channel model, it can inform the network device of the target channel model through the third indication information, so that the network device can reconstruct a more accurate precoding matrix based on the target channel model.

[0093] Optionally, before receiving the third indication information, the communication method further includes: sending first indication information, where the first indication information is used to indicate TA, and TA is used to determine the target channel model.

[0094] The network device may determine the TA based on the first signal and inform the terminal device of the TA, and the terminal device may determine the TA based on the TA. TA , and then according to d TA Determine the target channel model. Therefore, this embodiment can reuse the existing process (the process of the terminal device obtaining the TA) to determine the target channel model, thereby reducing the overhead of determining the target channel model.

[0095] Optionally, before receiving the third indication information, the communication method further includes: sending second indication information, the second indication information being used to indicate the trace of the spatial correlation matrix corresponding to the second channel model. ref ,tra ref is the average value of the trace of the spatial correlation matrix of multiple terminal devices applying the second channel model, tra ref Used to determine the target channel model.

[0096] In this embodiment, the terminal device can obtain the latest tra ref , the latest tra ref More compatible with current channel conditions, so based on the latest tra ref The determined target channel model is more accurate.

[0097] In a third aspect, embodiments of the present application provide a communication device. The communication device may include a processing unit and a transceiver unit, configured to perform any of the methods described in the first aspect and its optional embodiments. The transceiver unit is a sending unit when performing the sending step, and is a receiving unit when performing the receiving step.

[0098] In a fourth aspect, embodiments of the present application provide a communication device. The communication device may include a processing unit and a transceiver unit, configured to perform any of the methods described in the second aspect and its optional embodiments. The transceiver unit is a sending unit when performing the sending step, and a receiving unit when performing the receiving step.

[0099] In a fifth aspect, an embodiment of the present application provides a communication device, which may be a terminal device or a chip applied to a terminal device. The communication device may include a processor for executing any of the methods in the first aspect and its optional embodiments.

[0100] Optionally, when the communication device is a terminal device, the processor is, for example, a system on chip (SoC) or a central processor unit (CPU); when the communication device is a chip, the processor is, for example, a core, and the core may include at least one execution unit, and the execution unit is, for example, an arithmetic and logic unit (ALU).

[0101] Optionally, the communication device may further include a transceiver. When the communication device is a terminal device, the transceiver may be a transceiver circuit, an antenna, etc.; when the communication device is a chip used in a terminal device, the transceiver may be an input / output interface, a pin, a circuit, etc.

[0102] Optionally, the communication device may further include a memory for storing a computer program or instructions, and the processor executes the computer program or instructions stored in the memory, so that the communication device performs any of the methods in the first aspect and its optional embodiments described above. When the communication device is a terminal device, the memory may be a read-only memory, a random access memory, or the like; when the communication device is a chip applied to a terminal device, the memory may be a register, a cache, or the like.

[0103] In a sixth aspect, an embodiment of the present application provides a communication device, which may be a network device or a chip used in a network device. The communication device may include a processor configured to execute any of the methods in the second aspect and its optional embodiments.

[0104] Optionally, when the communication device is a network device, the processor is, for example, a CPU, an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA); when the communication device is a chip, the processor is, for example, a core, which may include at least one execution unit, such as an ALU.

[0105] Optionally, the communication device may further include a transceiver. When the communication device is a network device, the transceiver may be a transceiver circuit, an antenna, etc.; when the communication device is a chip used in a network device, the transceiver may be an input / output interface, a pin, a circuit, etc.

[0106] Optionally, the communication device may further include a memory for storing computer programs or instructions, and the processor executes the computer program or instructions stored in the memory to cause the communication device to perform any of the methods in the second aspect and its optional embodiments. When the communication device is a network device, the memory may be a read-only memory, a random access memory, or the like; when the communication device is a chip used in a network device, the memory may be a register, a cache, or the like.

[0107] In the seventh aspect, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed on a computer, it enables the computer to execute any method in the first aspect and its optional implementation methods.

[0108] In an eighth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed on a computer, the computer executes any one of the methods in the second aspect and its optional implementation methods.

[0109] In the ninth aspect, an embodiment of the present application provides a computer program product, which includes: computer program code or computer program instructions, which, when the computer program code or computer program instructions are executed by a communication device, enables the communication device to execute any one of the methods in the first aspect and its optional implementation methods.

[0110] In the tenth aspect, an embodiment of the present application provides a computer program product, which includes: computer program code or computer program instructions, which, when the computer program code or computer program instructions are executed by a communication device, enables the communication device to execute any one of the methods in the second aspect and its optional implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0111] FIG1 is a schematic diagram of a communication system applicable to the present application;

[0112] FIG2 is a schematic diagram of a protocol stack applicable to the present application;

[0113] FIG3 is a schematic diagram of a far-field channel model provided in an embodiment of the present application;

[0114] FIG4 is a schematic diagram of a near-field channel model provided in an embodiment of the present application;

[0115] FIG5 is a schematic diagram of a communication method provided in an embodiment of the present application;

[0116] FIG6 is a schematic diagram of a geometric relationship provided in an embodiment of the present application;

[0117] FIG7 is a flow chart of signaling interaction for feedback of PMI provided in an embodiment of the present application;

[0118] FIG8 is a flowchart of another signaling interaction for feedback of PMI provided in an embodiment of the present application;

[0119] FIG9 is a flow chart of signaling interaction for determining a target channel model according to an embodiment of the present application;

[0120] FIG10 is a flowchart of another signaling interaction for determining a target channel model according to an embodiment of the present application;

[0121] 11 is a flowchart of signaling interaction for determining a target channel model according to another embodiment of the present application;

[0122] FIG12 is a schematic diagram of a communication device provided in an embodiment of the present application;

[0123] FIG13 is a schematic diagram of another communication device provided in an embodiment of the present application;

[0124] FIG14 is a schematic diagram of a terminal device provided in an embodiment of the present application;

[0125] FIG15 is a schematic diagram of a network device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0126] The technical solution in this application will be described below with reference to the accompanying drawings.

[0127] Figure 1 is a schematic diagram of a communication system applicable to the present application. The communication system includes a terminal device 110 and a network device 120. The following describes each part of the communication system.

[0128] Ⅰ. Terminal device 110.

[0129] In the embodiment of the present application, the terminal device 110 may be a device that provides voice and / or data to a user, such as a handheld device or vehicle-mounted device with a wireless connection function. The terminal device 110 may also be referred to as user equipment (UE), terminal, access station, UE station, remote station, wireless communication device, or user device.

[0130] For example, the terminal device 110 can be a mobile phone, a tablet computer, a computer with wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a whole vehicle, a wireless communication module in the whole vehicle, a telematics box (T-box), a roadside unit (RSU), a wireless terminal in unmanned driving, a smart speaker in the Internet of Things (IoT), a wireless terminal device in remote medical, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, or a wireless terminal device in a smart home. The embodiments of the present application do not limit the specific technology and specific form adopted by the terminal device 110.

[0131] As an example and not a limitation, in the embodiment of the present application, the terminal device 110 may also be a wearable device. 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, clothing, and shoes. 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 electronic devices that are fully functional, large in size, and can achieve full or partial functions without relying on smartphones, such as smart watches or smart glasses, or electronic devices 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 measuring vital signs.

[0132] The terminal device 110 may also be a vehicle-to-everything (V2X) device, such as a smart car (or intelligent car), a digital car, an unmanned car (or driverless car, or pilotless car, or automobile), a self-driving car (or autonomous car), a pure electric vehicle (or battery EV), a hybrid electric vehicle (or HEV), a range-extended EV (or REEV), a plug-in hybrid electric vehicle (or PHEV), or a new energy vehicle. The various terminal devices described above, if located on a vehicle (e.g., placed inside or installed inside a vehicle), may be considered as on-board terminal devices, which are also referred to as on-board units (OBUs).

[0133] The terminal device 110 of the present application can also be a vehicle-mounted module, vehicle-mounted module, vehicle-mounted component, vehicle-mounted chip or vehicle-mounted unit built into the vehicle as one or more components or units. The vehicle can implement the method of the present application through the built-in vehicle-mounted module, vehicle-mounted module, vehicle-mounted component, vehicle-mounted chip or vehicle-mounted unit.

[0134] In addition, in the embodiment of the present application, the terminal device 110 may also be a device in a future-evolved public land mobile network (PLMN). For example, the terminal device 110 may be a terminal device in a sixth-generation mobile communication technology (6G) system. The embodiment of the present application does not limit the specific type of the terminal device 110.

[0135] II. Network equipment 120.

[0136] The network device 120 is a device that provides wireless communication functions for terminal devices and is responsible for functions related to the air interface (abbreviated as "air interface").

[0137] The network device 120 may also be referred to as a network apparatus or a radio access network (RAN) device. The network device 120 includes, but is not limited to, a base station (BS), an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation base station (gNB) in a fifth-generation (5G) mobile communication system, a next-generation base station in a 6G mobile communication system, a base station in a future mobile communication system, a wireless fidelity (WiFi) system, a long-range radio (LoRa) system, or an access node in an Internet of Vehicles system.

[0138] The RAN device can be a module or unit that performs some of the functions of the base station, for example, a centralized unit (CU), a distributed unit (DU), or a radio unit (RU). The CU here performs the functions of the radio resource control protocol and packet data convergence protocol (PDCP) of the base station, and can also perform the functions of the service data adaptation protocol (SDAP); the DU performs the functions of the radio link control layer and medium access control (MAC) layer of the base station, and can also perform some or all of the physical layer functions. For detailed descriptions of each of the above protocol layers, please refer to the relevant technical specifications of the 3rd Generation Partnership Project (3GPP). The CU and DU can be set separately or included in the same network element, such as the baseband unit (BBU). The RU can be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0139] In different systems, CU, DU or RU may have different names, but those skilled in the art can understand their meanings. For example, in an open radio access network (ORAN) system, CU may also be referred to as an open CU (O-CU), DU may also be referred to as an open DU (O-DU), and RU may also be referred to as an open RU (O-RU). Any of the CU, DU and RU in this application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0140] The RAN device can be a macro base station, a micro base station, an indoor station, a relay node, or a donor node. The RAN device can also be a base station corresponding to a small cell, where the small cell can include: a metro cell, a micro cell, a pico cell, or a femto cell. The network device 120 in the embodiments of the present application can be any of the above devices or devices in the devices, and the embodiments of the present application do not limit the specific technology and specific device form adopted by the network device 120. For ease of description, the RAN device can be used as an abbreviation for the network device 120, and the base station can be used as an example of a RAN device.

[0141] Base stations and terminals can be fixed or mobile. They can be deployed on land, indoors or outdoors, handheld or vehicle-mounted; on water; or on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of base stations and terminals.

[0142] The roles of base stations and terminals can be relative. For example, a drone (or helicopter) can be configured as a mobile base station. For terminals that access network device 120 via the drone, the drone is a base station; but for network device 120, the drone is a terminal, that is, communication between network device 120 and the drone is carried out via a wireless air interface protocol. Of course, communication between network device 120 and the drone can also be carried out via an interface protocol between base stations. In this case, relative to network device 120, the drone is also a base station. Therefore, base stations and terminals can be collectively referred to as communication devices. Network device 120 in Figure 1 can be referred to as a communication device with base station functions, and terminal device 110 in Figure 1 can be referred to as a communication device with terminal functions.

[0143] Communication between base stations and terminals, between base stations, and between terminals can be carried out through authorized spectrum, unauthorized spectrum, or both; communication can be carried out through spectrum below 6 gigahertz (GHz), spectrum above 6 GHz, or spectrum below 6 GHz and spectrum above 6 GHz. The embodiments of the present application do not limit the spectrum resources used for wireless communication.

[0144] In the embodiments of the present application, the functions of the base station may also be performed by a module (such as a chip) in the base station, or by a control subsystem that includes the base station functions. The control subsystem that includes the base station functions here may be a control center in the above-mentioned application scenarios such as smart grid, industrial control, smart transportation, and smart city. The functions of the terminal may also be performed by a module (such as a chip or modem) in the terminal, or by a device that includes the terminal functions.

[0145] In this application, a base station sends downlink signals or downlink information to a terminal, and the downlink information is carried on a downlink channel; the terminal sends uplink signals or uplink information to the base station, and the uplink information is carried on an uplink channel. In order to communicate with the base station, the terminal needs to establish a wireless connection in the cell controlled by the base station. The cell with which the terminal has established a wireless connection is called the serving cell of the terminal. When the terminal communicates with the serving cell, it will also be interfered with by signals from neighboring cells.

[0146] The following describes the protocol stack applicable to this application.

[0147] The protocol stack of the terminal device 110 and the network device 120 is shown in Figure 2. This protocol stack is mainly the protocol stack of the access layer, where the access layer can be divided into the radio resource control (RRC) layer, the PDCP layer, the radio link control (RLC) layer, the MAC layer, and the physical (PHY) layer.

[0148] The following describes the workflow of the protocol stack using uplink transmission as an example.

[0149] (1) The main functions of the RRC layer include system messages, admission control, security management, measurement and reporting, as well as handover and mobility. The control plane data related to these functions is generated in the non-access stratum (NAS). The RRC layer is also responsible for the radio resource management of the transmission of NAS protocol data units (PDUs). After the NAS PDU reaches the RRC layer, it is processed as an RRC service data unit (SDU) to generate an RRC PDU. The control plane data generated by the RRC layer (such as RRC reconfiguration messages) is also packaged into RRC PDUs.

[0150] (2) The main functions of the PDCP layer include transmitting user plane and control plane data, maintaining PDCP sequence numbers, routing and repetition, encryption / decryption and integrity protection, reordering, supporting out-of-order delivery, and duplicate discard. After the RRC PDU reaches the PDCP layer, it is processed as a PDCP SDU to generate a PDCP PDU.

[0151] (3) The main functions of the RLC layer include error detection and correction, segmentation and reassembly, resegmentation, and duplicate packet detection. After the PDCP PDU reaches the RLC layer, it is processed as an RLC SDU and generates an RLC PDU.

[0152] (4) The main functions of the MAC layer include mapping between logical channels and transport channels, multiplexing / demultiplexing, scheduling, hybrid automatic repeat request (HARQ), and logical channel priority setting. After the RLC PDU reaches the MAC layer, it is processed as a MAC SDU to generate a MAC sub-PDU. Multiple MAC sub-PDUs are concatenated to form a MAC PDU.

[0153] (5) The main functions of the PHY layer include coding, modulation, and multiple-input multiple-output (MIMO). After the MAC PDU reaches the PHY layer, it is sent out on the corresponding time-frequency resources.

[0154] As can be seen above, data transferred between the same protocol layers can be called SDUs, and data transferred between adjacent protocol layers can be called PDUs. For a protocol layer, the data it processes can be called SDUs, and the data it outputs can be called PDUs.

[0155] For example, the data processed by the RRC layer of terminal device 110 is an RRC SDU. The RRC layer adds protocol control information (PCI) to the RRC SDU and encapsulates it into an RRC PDU. The RRC PDU is processed by the PDCP layer, RLC layer, MAC layer, and PHY layer, and then transmitted to network device 120 via a wireless signal. The information carried by the wireless signal reaching network device 120 is processed by the PHY layer, MAC layer, RLC layer, and PDCP layer in sequence, and reaches the RRC layer in the form of an RRC PDU. The RRC layer decapsulates the RRC PDU, removes the PCI, and restores the RRC SDU.

[0156] If the data volume of an SDU is large, the terminal device 110 can divide the SDU into multiple segments, encapsulate them into multiple PDUs, and send them out. The network device 120 then decapsulates the multiple PDUs and reassembles them into an SDU. If the data volume of multiple SDUs is small, the terminal device 110 can concatenate the multiple SDUs, encapsulate them into a single PDU, and send them out. The network device 120 then decapsulates the PDU and separates the multiple SDUs.

[0157] To facilitate understanding of the embodiments of the present application, the following is a brief introduction to the technologies involved in the embodiments of the present application.

[0158] 1. Precoding technology.

[0159] The transmitting device (such as a network device) can process the signal to be transmitted with the help of a precoding matrix that matches the channel state when the channel state is known, so that the precoded signal to be transmitted is adapted to the channel, thereby reducing the complexity of the receiving device (such as a terminal device) in eliminating the influence between channels. Therefore, by precoding the signal to be transmitted, the quality of the received signal (such as the signal to interference plus noise ratio (SINR)) is improved. Therefore, the use of precoding technology can realize the transmission of the transmitting device and multiple receiving devices on the same time-frequency resources, that is, multiple user multiple input multiple output (MU-MIMO) is realized.

[0160] It should be understood that the description of the relevant precoding technology is merely an example for ease of understanding and is not intended to limit the scope of protection of the embodiments of this application. In a specific implementation, the transmitting device may also perform precoding in other ways. For example, when channel information (e.g., a channel matrix) is not available, precoding may be performed using a pre-set precoding matrix or weighted processing method. For the sake of brevity, this description will not be repeated.

[0161] 2. Channel state information (CSI)

[0162] In a wireless communication system, information used to describe the channel properties of a communication link reported by a receiving device to a transmitting device. For example, a CSI report may include: PMI, rank indication (RI), channel quality indicator (CQI), channel state information reference signal (CSI-RS) resource indicator (CSI-RS resource indicator, CRI) and layer indicator (LI), etc. It should be understood that the specific contents of the CSI listed above are only exemplary and do not constitute any limitation to this application. CSI may include one or more of the items listed above, and may also include other information used to characterize CSI in addition to the above-mentioned items, and this application does not limit this.

[0163] 3. PMI.

[0164] PMI can be used to indicate a precoding matrix, which can be, for example, a precoding matrix determined by the terminal device based on a channel matrix of each frequency domain unit. The channel matrix can be determined by the terminal device through channel estimation or based on channel reciprocity.

[0165] 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. It should be understood that the methods for determining the precoding matrix listed above are only examples and should not constitute any limitation to this application. For the sake of brevity, they are not listed here one by one.

[0166] The precoding matrix determined by the terminal device can be referred to as the precoding matrix to be fed back, or in other words, the precoding matrix to be reported. The terminal device can indicate the precoding matrix to be fed back through the PMI, so that the network device can recover the precoding matrix based on the PMI. The precoding matrix recovered by the network device based on the PMI can be the same as or similar to the precoding matrix to be fed back.

[0167] The network device can determine the precoding matrix corresponding to one or more frequency domain units based on the feedback of the terminal device. The precoding matrix thus determined by the network device can be used directly for downlink data transmission; or it can be processed to obtain the precoding matrix ultimately used for downlink data transmission. The beamforming method is, for example: zero forcing (ZF), regularized zero-forcing (RZF), minimum mean-squared error (MMSE), or maximizing the signal-to-leakage-and-noise ratio (SLNR). This application is not limited to this.

[0168] In downlink channel measurement, the higher the degree of similarity between the precoding matrix recovered by the network device based on the PMI and the precoding matrix determined by the terminal device, the more adaptable the precoding matrix determined by the network device for data transmission will be to the downlink channel, thereby improving the signal transmission quality.

[0169] It should be understood that PMI is only an exemplary name and should not constitute any limitation to this application. This application does not exclude the possibility of defining signaling with other names in future protocols to represent the same or similar functions.

[0170] 4. Spatial layer (layer).

[0171] A spatial layer may also be referred to as a transport layer, layer, transport stream, spatial stream, or stream. In an embodiment of the present application, the number of spatial layers may be determined by the rank fed back by the terminal device based on channel measurement. For example, the number of spatial layers may be equal to the rank fed back by the terminal device based on channel measurement.

[0172] In MIMO, a spatial layer can be viewed as an independently transmittable data stream. To improve spectrum resource utilization and the data transmission capacity of the communication system, network equipment can transmit data to terminal devices via multiple spatial layers.

[0173] The number of spatial layers is also the rank of the channel matrix. The terminal device can determine the number of spatial layers R based on the channel matrix obtained by channel estimation, and further determine the precoding matrix. For example, the precoding matrix can be determined by performing SVD on the channel matrix or the covariance matrix of the channel matrix. In the SVD process, different spatial layers can be distinguished according to the size of the eigenvalue. For example, the precoding vector determined by the eigenvector corresponding to the largest eigenvalue can be corresponded to the first spatial layer, and the precoding vector determined by the eigenvector corresponding to the smallest eigenvalue can be corresponded to the Rth spatial layer. That is, the eigenvalues ​​corresponding to the 1st spatial layer to the Rth spatial layer decrease in sequence. Simply put, the strength of the R spatial layers decreases from the 1st spatial layer to the Rth spatial layer.

[0174] It should be understood that distinguishing different spatial layers based on characteristic values ​​is only one possible implementation method and does not constitute any limitation to this application. For example, the protocol may also predefine other criteria for distinguishing spatial layers, which is not limited in this application.

[0175] 5. Precoding vector.

[0176] A precoding matrix may include one or more vectors, such as column vectors. A precoding matrix may be used to determine one or more precoding vectors.

[0177] When the number of spatial layers is 1 and the number of polarization directions of the transmit antenna is also 1, the precoding matrix is ​​the precoding vector. When the number of spatial layers is multiple and the number of polarization directions of the transmit antenna is 1, the precoding vector can refer to the components of the precoding matrix in one spatial layer. When the number of spatial layers is 1 and the number of polarization directions of the transmit antenna is multiple, the precoding vector can refer to the components of the precoding matrix in one polarization direction. When the number of spatial layers is multiple and the number of polarization directions of the transmit antenna is also multiple, the precoding vector can refer to the components of the precoding matrix in one spatial layer and one polarization direction.

[0178] It should be understood that the precoding vector can also be determined by the vector in the precoding matrix, for example, obtained by performing a mathematical transformation on the vector in the precoding matrix. This application does not limit the mathematical transformation relationship between the precoding matrix and the precoding vector.

[0179] 6. Antenna port.

[0180] The antenna port can be simply referred to as a port. It can be understood as a transmitting antenna recognized by the receiving device, or a transmitting antenna that can be distinguished in space. An antenna port can be pre-configured for each virtual antenna, and each virtual antenna can be a weighted combination of multiple physical antennas. Each antenna port can correspond to a reference signal, so each antenna port can be called a reference signal port, for example, a CSI-RS port, an SRS port, etc. In an embodiment of the present application, the reference signal can be a non-precoded reference signal or a precoded reference signal, and this application does not limit this. When the reference signal is a precoded reference signal, the reference signal port can be a transmitting antenna port, and the transmitting antenna port can refer to an independent transceiver unit.

[0181] 7. Airspace base.

[0182] A spatial basis can also be called a spatial domain vector, spatial component vector, beam vector, spatial beam basis vector, or spatial basis vector. Each element in a spatial vector represents the weight of each antenna port. By linearly superimposing the signals from each antenna port based on the weights represented by each element in the spatial vector, a region with a strong signal can be formed in a certain spatial direction.

[0183] The length of the spatial vector can be the number of transmitting antenna ports N in one polarization direction. s , N s ≥1 and is an integer. The spatial vector can be, for example, of length N s This application does not limit this.

[0184] Optionally, the spatial domain vector is a discrete Fourier transform (DFT) vector. The DFT vector may refer to a vector in a DFT matrix.

[0185] Optionally, the spatial domain vector is a conjugate transposed vector of the DFT vector. The DFT conjugate transposed vector may refer to a column vector in a conjugate transposed matrix of the DFT matrix.

[0186] Optionally, the spatial domain vector is an oversampled DFT vector. The oversampled DFT vector may refer to a vector in an oversampled DFT matrix.

[0187] In the embodiment of the present application, the spatial domain vector is one of the vectors used to construct the precoding matrix.

[0188] 8. Spatial basis set.

[0189] The spatial basis set may also be referred to as a candidate spatial vector set, a candidate spatial component vector set, a spatial component vector set, a candidate spatial basis vector set, a spatial basis vector set, a candidate beam vector set, a beam vector set, a candidate spatial beam basis vector set, a spatial beam basis vector set, etc. A plurality of spatial vectors (or candidate spatial vectors) of different lengths may be included to correspond to different numbers of antenna ports. In an embodiment of the present application, the spatial vector used to construct the precoding vector may be determined from the candidate spatial vector set. In other words, the candidate spatial vector set includes a plurality of candidate spatial vectors that can be used to construct the precoding vector.

[0190] In one possible design, the candidate spatial vector set may include N s candidate spatial domain vectors, the N s The candidate spatial vectors can be mutually orthogonal. Each candidate spatial vector in the candidate spatial vector set can be a vector in a 2D-DFT matrix, where 2D can represent two different directions, for example, horizontal and vertical directions. If the number of antenna ports in the horizontal and vertical directions is N1 and N2 respectively, then N s =N1×N2. N s , N1 and N2 are all positive integers.

[0191] N s The candidate spatial vectors can be written as The N s The candidate spatial vectors can construct the matrix B s , Matrix B s Can be used for spatial compression as described below to select one or more candidate spatial vectors for constructing the precoding matrix. If each candidate spatial vector in the set of candidate spatial vectors is taken from a 2D-DFT matrix, then Among them D N Represents an N×N orthogonal DFT matrix, the element in the mth row and nth column of the orthogonal DFT matrix is

[0192] In another possible design, the candidate spatial vector set can be obtained by oversampling factor O s Expand to O s ×N s In this case, the candidate spatial vector set may include O s subsets, each subset can include N s candidate spatial domain vectors. N in each subset sThe candidate spatial vectors can be mutually orthogonal. Each candidate spatial vector in the candidate spatial vector set can be taken from the oversampled 2D-DFT matrix. For example, the oversampling factor O s is a positive integer, O s =O1×O2, O1 can be the oversampling factor in the horizontal direction, O2 can be the oversampling factor in the vertical direction, O1≥1, O2≥1, O1 and O2 cannot be 1 at the same time, and both are positive integers.

[0193] The oth vector in the candidate spatial domain vector set s (0≤o s ≤O s -1, and o s N of the subsets (integer) s The candidate spatial vectors can be expressed as Based on the o s N of the subsets s The candidate spatial vectors can construct the matrix By O s A matrix composed of one or more subsets of the subsets can be used to perform the spatial domain compression described below to select one or more spatial domain vectors for constructing a precoding matrix.

[0194] It should be understood that the present application does not limit the specific form of the candidate spatial vector set and the specific form of the candidate spatial vector.

[0195] 9. Frequency domain unit.

[0196] The frequency domain unit is a unit of frequency domain resources and can represent different frequency domain resource granularities. The frequency domain unit may include, for example: a subband, a resource block (RB), a subcarrier, a resource block group (RBG), or a precoding resource block group (PRG). In addition, the frequency domain length of a frequency domain unit may also be R times the CQI subband, where R is less than or equal to 1, and the value of R may be, for example, 1, or the value of R may be pre-configured to the terminal device by the network device through signaling. In addition, the frequency domain length of a frequency domain unit may also be RB.

[0197] In the embodiments of the present application, the precoding matrix corresponding to a frequency domain unit may refer to a precoding matrix determined by performing channel measurement and feedback based on a reference signal on the frequency domain unit. The precoding matrix corresponding to the frequency domain unit may be used to precode data subsequently transmitted via the frequency domain unit. Hereinafter, the precoding matrix corresponding to a frequency domain unit may also be referred to as the precoding matrix of the frequency domain unit.

[0198] 10. Frequency domain basis.

[0199] The frequency domain basis, also known as a frequency domain vector, frequency domain component vector, or frequency domain basis vector, can be used to represent the channel's frequency domain variation. Each frequency domain vector can represent a specific variation. When a signal is transmitted through a wireless channel, it can travel through multiple paths from the transmitting antenna to the receiving antenna. Multipath delay causes frequency-selective fading, which is a variation of the frequency domain channel. Therefore, different frequency domain vectors can be used to represent the frequency domain variation of the channel caused by delays along different transmission paths.

[0200] The length of the frequency domain vector can be recorded as N f , N f is a positive integer, the frequency domain vector can be, for example, of length N f The length of the frequency domain vector can be determined by the number of frequency domain units to be reported pre-configured in the reporting bandwidth, or by the length of the reporting bandwidth, or by a protocol predefined value. This application does not limit the length of the frequency domain vector. The reporting bandwidth may, for example, refer to the CSI reporting bandwidth (csi-ReportingBand) carried in the CSI reporting pre-configuration in the higher layer signaling.

[0201] The frequency domain vectors corresponding to all spatial domain vectors corresponding to each spatial layer can be called the frequency domain vectors corresponding to the spatial layer. The frequency domain vectors corresponding to each spatial layer can be the same or different.

[0202] 11. Frequency domain basis set.

[0203] The frequency domain basis set may also be referred to as a candidate frequency domain vector set, a candidate frequency domain component vector set, a frequency domain component vector set, a frequency domain basis vector set, or a frequency domain vector set, and may include candidate frequency domain vectors of various lengths. In an embodiment of the present application, the frequency domain vector used to construct the precoding vector may be determined from the candidate frequency domain vector set. In other words, the candidate frequency domain vector set includes multiple candidate frequency domain vectors that can be used to construct the precoding vector.

[0204] In one possible design, the candidate frequency domain vector set may include N f candidate frequency domain vectors. fThe candidate frequency domain vectors may be mutually orthogonal to each other. Each candidate frequency domain vector in the candidate frequency domain vector set may be a vector in a DFT matrix or an inverse discrete Fourier transform (IDFT) matrix, wherein the IDFT matrix is ​​the conjugate transposed matrix of the DFT matrix.

[0205] The N f The candidate frequency domain vectors can be expressed as The N f The candidate frequency domain vectors can construct the matrix B f , This matrix may be used to perform frequency domain compression as described below to select one or more frequency domain vectors used to construct a precoding matrix.

[0206] In another possible design, the candidate frequency domain vector set can be oversampled by a factor of O. f Expand to O f ×N f In this case, the candidate frequency domain vector set may include O f subsets, each subset can include N f candidate frequency domain basis vectors. N in each subset f The candidate frequency domain basis vectors can be mutually orthogonal. Each candidate frequency domain vector in the candidate frequency domain vector set can be taken from the oversampled DFT matrix or the conjugate transposed matrix of the oversampled DFT matrix. f Is a positive integer.

[0207] Therefore, each candidate frequency domain vector in the candidate frequency domain vector set can be taken from a DFT matrix or an oversampled DFT matrix, or from the conjugate transposed matrix of a DFT matrix or the conjugate transposed matrix of an oversampled DFT matrix. Each column vector in the candidate frequency domain vector set can be referred to as a DFT vector or an oversampled DFT vector. In other words, the candidate frequency domain vector can be a DFT vector or an oversampled DFT vector.

[0208] 12. Space-frequency vector pair.

[0209] A space-frequency vector pair can also be called a space-frequency component vector. A space-domain vector and a frequency-domain vector can be combined to obtain a space-frequency vector pair. In other words, a space-frequency vector pair can include a space-domain vector and a frequency-domain vector. A space-frequency component matrix can be obtained from the space-domain vector and the frequency-domain vector in a space-frequency vector pair. For example, multiplying a space-domain vector by the conjugate transpose of a frequency-domain vector can obtain a space-frequency component matrix. The space-frequency component matrix described here is relative to the space-frequency matrix described below. Since a space-frequency matrix can be obtained by weighted summation of multiple space-frequency component matrices, each item used for weighting can be called a component of a space-frequency matrix, that is, the space-frequency component matrix mentioned here.

[0210] 13. Space-frequency matrix.

[0211] In the embodiments of the present application, the space-frequency matrix can be understood as an intermediate quantity used to determine the precoding matrix or channel matrix corresponding to each frequency domain unit. For a terminal device, the space-frequency matrix can be determined by the precoding matrix or channel matrix corresponding to each frequency domain unit. For a network device, the space-frequency matrix can be obtained by taking the weighted sum of multiple space-frequency component matrices to recover the channel matrix or precoding matrix.

[0212] For example, the space-frequency matrix can be denoted as W, Among them, w0 to Yes and N f The frequency domain units correspond to N f column vectors, each column vector can be the precoding matrix corresponding to each frequency domain unit. f The column vectors correspond to N f The precoding vector of frequency domain units. That is, the space-frequency matrix can be regarded as N f The joint matrix is ​​composed of the precoding vectors corresponding to the frequency domain units.

[0213] In one possible design, the space-frequency matrix may correspond to the spatial layer. The space-frequency matrix is ​​said to correspond to the spatial layer because the terminal device can feed back the frequency domain vector and the space-frequency combining coefficient based on each spatial layer. The space-frequency matrix determined by the network device based on the feedback of the terminal device is the space-frequency matrix corresponding to the spatial layer. The space-frequency matrix corresponding to the spatial layer can be directly used to determine the precoding matrix corresponding to each frequency domain unit. The precoding matrix corresponding to a certain frequency domain unit can be constructed, for example, by the column vector corresponding to the same frequency domain unit in the space-frequency matrix corresponding to each spatial layer. For example, the nth (0≤n≤N3-1, and n is an integer) column vector in the space-frequency matrix corresponding to each spatial layer is extracted and arranged from left to right in the order of the spatial layers to obtain a precoding matrix of dimension N. sThe matrix is ​​a matrix of size 1 × Z, where Z represents the number of spatial layers and is an integer ≥ 1. The matrix is ​​normalized, for example, by multiplying it by a power normalization coefficient, to obtain the precoding matrix of the nth frequency domain unit.

[0214] It should be understood that normalizing the matrix by multiplying the power normalization coefficient is only one possible implementation method and should not constitute any limitation to the present application. The present application does not limit the specific method of normalization.

[0215] It should be understood that the space-frequency matrix is ​​only a form of expression for determining the intermediate quantity of the precoding matrix or the channel matrix and should not constitute any limitation to the present application. For example, the column vectors in the space-frequency matrix can be connected in order from left to right, or arranged according to other predefined rules to obtain a length of N. s ×N f The vector of , which can be called the space-frequency vector.

[0216] It should also be understood that the dimensions of the space-frequency matrix and space-frequency vector shown above are only examples and should not constitute any limitation to this application. For example, the space-frequency matrix can also be of dimension N f ×N s Each row vector may correspond to a frequency domain unit and is used to determine the precoding vector of the corresponding frequency domain unit.

[0217] In addition, when the transmitting antenna is configured with multiple polarization directions, the dimension of the space-frequency matrix can be further expanded. For example, for a dual-polarization antenna, the dimension of the space-frequency matrix can be 2N s ×N f or N f ×2N s It should be understood that the present application does not limit the number of polarization directions of the transmitting antenna.

[0218] 14. Combination coefficient.

[0219] The combination coefficient can also be called the space-frequency combining coefficient, space-frequency coefficient, combining coefficient, or weighting coefficient, etc. Each space-frequency combining coefficient may correspond to a space-domain vector and a frequency-domain vector, or in other words, each space-frequency combining coefficient may correspond to a space-frequency vector pair. Each space-frequency combining coefficient is a weighting coefficient (or, weight) of the space-frequency component matrix constructed by the space-frequency vector pair to which it corresponds. The space-frequency combining coefficient corresponds to a space-domain vector and a frequency-domain vector. Specifically, the element in the i-th row and j-th column of the space-frequency combining coefficient matrix is ​​the space-frequency combining coefficient corresponding to the space-frequency vector pair composed of the i-th space-domain vector and the j-th frequency-domain vector. For dual-polarization directional antennas, the above i∈{1,2,...,2L}, and the length of each space-domain vector is 2N. s .

[0220] In one implementation, in order to control the reporting overhead, the terminal device may only report the space-frequency combining coefficient matrix For example, the network device can configure the maximum number of space-frequency combining coefficients K0 that can be reported by the terminal device corresponding to each spatial layer, where K0≤2LM. K0 is related to The total number of space-frequency combining coefficients 2LM included in may have a proportional relationship, for example, K0 = β·2LM, and the value of β may be In addition, the terminal device may only report K1 space-frequency combining coefficients with non-zero amplitudes, where K1≤K0.

[0221] Each space-frequency combining coefficient may include amplitude and phase. For example, the space-frequency combining coefficient ae jθ In this equation, a is the amplitude and θ is the phase.

[0222] In one implementation, the amplitude and phase values ​​of the K1 reported space-frequency combining coefficients can be independently quantized. The amplitude quantization method includes the following steps:

[0223] 1) For K1 space-frequency combining coefficients, take the space-frequency combining coefficient with the largest amplitude value as reference and normalize the K1 space-frequency combining coefficients. If the i-th space-frequency combining coefficient is c before normalization, i , then after normalization it is c i ′=c i / c i ·, where c i · is the space-frequency combining coefficient with the largest amplitude value. After normalization, the space-frequency combining coefficient with the largest quantized reference amplitude value is 1.

[0224] 2) The terminal device reports the index of the space-frequency combining coefficient with the largest amplitude value. The indication information indicating the index of the space-frequency combining coefficient with the largest amplitude value may include: bit.

[0225] 3) For the polarization direction where the space-frequency combining coefficient with the largest amplitude value is located, the quantization reference amplitude value is 1. For the other polarization direction, the amplitude of the space-frequency combining coefficient with the largest amplitude value in that polarization direction can be used as the quantization reference amplitude value of that polarization direction. The quantization reference amplitude value is quantized using 4 bits and reported. The candidate quantization reference amplitude values ​​include

[0226] 4) For each polarization direction, the quantization reference amplitude value corresponding to the polarization direction is used as a reference, and the differential amplitude value of each space-frequency combining coefficient is quantized by 3 bits. The candidate differential amplitude values ​​include The differential amplitude value represents the difference value relative to the quantization reference amplitude value corresponding to the polarization direction. If the quantization reference amplitude value corresponding to the polarization direction of a space-frequency combining coefficient is A, and the differential amplitude value of the space-frequency combining coefficient after quantization is B, then the amplitude value of the space-frequency combining coefficient after quantization is A*B.

[0227] 5) The phase of each normalized space-frequency combining coefficient is quantized using 3 bits or 4 bits, where 3 bits can be used for an 8-phase shift keying (PSK) scenario and 4 bits can be used for a 16PSK scenario.

[0228] Among the multiple space-frequency vector pairs selected by the terminal device for constructing the precoding matrix, each space-frequency vector pair may correspond to a space-frequency combining coefficient. Among the multiple space-frequency combining coefficients corresponding to the multiple space-frequency vector pairs, the amplitude values ​​of some space-frequency combining coefficients may be zero or close to zero, and their corresponding quantization values ​​may be zero. The space-frequency combining coefficients whose amplitudes are quantized by the quantization value zero can be called space-frequency combining coefficients with zero amplitude. Correspondingly, the amplitude values ​​of some space-frequency combining coefficients are large, and their corresponding quantization values ​​are not zero. The space-frequency combining coefficients whose amplitudes are quantized by non-zero quantization values ​​can be called space-frequency combining coefficients with non-zero amplitude. In other words, the multiple space-frequency combining coefficients corresponding to the multiple space-frequency vector pairs may be composed of one or more space-frequency combining coefficients with non-zero amplitudes and one or more space-frequency combining coefficients with zero amplitude.

[0229] It should be understood that the space-frequency combining coefficient can be indicated by a quantized value, an index of the quantized value, or a non-quantized value. This application does not limit the indication method of the space-frequency combining coefficient, as long as the receiving end can obtain the space-frequency combining coefficient. Hereinafter, for convenience of explanation, the information used to indicate the space-frequency combining coefficient is referred to as quantized information of the space-frequency combining coefficient. This quantized information can be, for example, a quantized value, an index, or any other information that can be used to indicate the space-frequency combining coefficient.

[0230] 15. Dual-domain compression.

[0231] Dual-domain compression can include compression in two dimensions: spatial domain compression and frequency domain compression. Spatial domain compression can specifically refer to selecting one or more spatial domain vectors from a set of spatial domain vectors as vectors for constructing a precoding matrix. Frequency domain compression can refer to selecting one or more frequency domain vectors from a set of frequency domain vectors as vectors for constructing a precoding matrix. As mentioned above, a matrix constructed by a spatial domain vector and a frequency domain vector can be called a space-frequency component matrix. The selected one or more spatial domain vectors and one or more frequency domain vectors can construct one or more space-frequency component matrices. The weighted sum of the one or more space-frequency component matrices can be used to construct a space-frequency matrix corresponding to a spatial layer. In other words, the space-frequency matrix can be approximated as the weighted sum of the space-frequency component matrices constructed by the above-mentioned selected one or more spatial domain vectors and one or more frequency domain vectors. Based on the space-frequency matrix corresponding to a spatial layer, the precoding vector corresponding to each frequency domain unit on the spatial layer can be determined.

[0232] For example, the selected one or more spatial domain vectors may constitute a matrix W1, wherein each column vector in W1 corresponds to a selected spatial domain vector. The selected one or more frequency domain vectors may constitute a matrix W3, wherein each column vector in W3 corresponds to a selected frequency domain vector. The space-frequency matrix W may be represented as the result of linearly merging the selected one or more spatial domain vectors with the selected one or more frequency domain vectors. Taking the space-frequency matrix corresponding to the spatial layer as an example, the space-frequency matrix corresponding to a spatial layer may be represented as

[0233] When the rank R is greater than 1, the spatial domain vectors used by each spatial layer may not be exactly the same, that is, each spatial layer uses an independent spatial domain vector; the spatial domain vectors used by each spatial layer may also be the same, that is, multiple spatial layers share L spatial domain vectors.

[0234] When the rank R is greater than 1, the frequency domain vectors used by each spatial layer may not be exactly the same, that is, each spatial layer uses an independent frequency domain vector; the frequency domain vectors used by each spatial layer may also be the same, that is, multiple spatial layers share M frequency domain vectors. Assume that each spatial layer uses its own independent frequency domain vector. For example, the i-th (0≤i≤R-1, i is an integer) spatial layer in the R spatial layers corresponds to M i frequency domain vectors, that is, the frequency domain vector corresponding to the i-th spatial layer reported by the terminal device is M i Among them, M i ≥1, and M i is an integer.

[0235] In this case, the precoding vector corresponding to each frequency domain unit on the i-th spatial layer can be based on the above L spatial domain vectors and M i The frequency domain vectors are constructed.

[0236] If a dual-polarization transmitting antenna is used, L spatial vectors can be selected for each polarization direction. Then the dimension of W1 can be 2N s ×2L. In one possible implementation, the two polarization directions can use the same L spatial vectors in, For example, it can be L spatial vectors selected from the spatial vector set mentioned above. In this case, W1 can be expressed as:

[0237] in, Represents the i-th spatial domain vector among the selected L spatial domain vectors, i = 0, 1, ..., L-1.

[0238] For the i-th spatial layer, W3 H The dimension can be M i ×N f Each column vector in W3 can be a frequency domain vector. At this time, each spatial domain vector in W1 and each frequency domain vector in W3 can form a spatial frequency vector pair, and each spatial frequency vector pair can correspond to a spatial frequency combining coefficient. Then there are 2L spatial domain vectors and M i 2L×M constructed by frequency domain vectors i Space-frequency vector pairs and 2L×M i The space-frequency combining coefficients correspond one to one.

[0239] For the i-th spatial layer, It can be made of the above 2L×M i The coefficient matrix composed of space-frequency combining coefficients can be 2L×M i . The lth row in can correspond to the lth spatial vector in the first polarization direction among the 2L spatial vectors, The L+1th row in may correspond to the lth spatial vector in the second polarization direction among the 2L spatial vectors. The mth (0≤m≤M i -1, and m is an integer) columns can correspond to M i The mth frequency domain vector among the frequency domain vectors.

[0240] Therefore, in the dual-domain compression feedback method, the frequency domain vector and the spatial domain vector corresponding to each spatial layer in the R spatial layers are selected to construct the position of the space-frequency vector pair of the precoding matrix and the space-frequency combining coefficient of each space-frequency vector pair.

[0241] The position of the space-frequency vector pair used to construct the precoding matrix specifically refers to the position of the spatial domain vector of the precoding matrix used to construct the precoding matrix in the spatial domain vector reported by the terminal device, and the position of the frequency domain vector of the precoding matrix used to construct the precoding matrix in the frequency domain vector reported by the terminal device. Since each space-frequency vector pair corresponds to a non-zero space-frequency combining coefficient (referred to as a non-zero coefficient), the position of the space-frequency vector pair used to construct the precoding matrix is ​​also the position of the non-zero coefficient.

[0242] It should be understood that the relationships between the various spatial layers and the spatial domain vectors and frequency domain vectors listed above are merely examples and should not constitute any limitation to this application.

[0243] It should also be understood that the relationship between the space-frequency matrix W and W1, W3 shown above is only an example and should not constitute any limitation to the present application. Based on the same concept, those skilled in the art can perform mathematical transformation on the above relationship to obtain other calculation formulas for representing the relationship between the space-frequency matrix W and W1, W3. For example, the space-frequency matrix W can also be expressed as In this case, each row vector in W3 may correspond to a selected frequency domain vector.

[0244] Because dual-domain compression performs compression in both the spatial and frequency domains, the terminal device can feed back one or more selected spatial domain vectors and one or more frequency domain vectors to the network device when providing feedback, eliminating the need to feed back the space-frequency combining coefficients for each frequency domain unit. Therefore, dual-domain compression can reduce feedback overhead. Furthermore, because frequency domain vectors can represent the frequency variation of the channel, simulating the frequency variation of the channel through the linear superposition of one or more frequency domain vectors maintains high feedback accuracy, allowing the network device to still effectively adapt to the channel based on the precoding matrix recovered by the terminal device's feedback.

[0245] It should be understood that in order to facilitate the understanding of dual-domain compression, the above text introduces the terms space-frequency matrix, space-frequency vector, etc., but this should not constitute any limitation on this application. The specific process of the terminal device determining the PMI is the internal implementation behavior of the terminal device, and this application does not limit the specific process of the terminal device determining the PMI. The specific process of the network device determining the precoding matrix based on the PMI is the internal implementation behavior of the network device, and this application does not limit the specific process of the network device determining the precoding matrix based on the PMI.

[0246] As an optional example, the terminal device may report the following information to the network device via the PMI:

[0247] The index of the spatial domain vector contained in the W1 matrix corresponding to each spatial layer;

[0248] The index of the frequency domain vector contained in the W3 matrix corresponding to each spatial layer.

[0249] The index of the spatial domain vector and the index of the frequency domain vector may be referred to as a codebook index. The network device determines the corresponding spatial domain vector and frequency domain vector from the codebook based on the codebook index to restore the channel matrix or precoding matrix.

[0250] 16. Far-field channel model and near-field channel model.

[0251] Figure 3 is a schematic diagram of a far-field channel model provided in an embodiment of the present application. In a far-field channel model, the distance from each antenna element in the antenna array to the nearest scatterer is approximately the same, and the propagation of electromagnetic waves follows the plane wave law. Therefore, the far-field channel model needs to consider the multipath angle parameter, but does not need to consider the distance from the antenna element to the scatterer.

[0252] Figure 4 is a schematic diagram of a near-field channel model provided in an embodiment of the present application. In a near-field channel model, the distances from each antenna element in the antenna array to the nearest scatterer vary significantly, and the propagation of electromagnetic waves follows the law of spherical waves. Therefore, in addition to considering the multipath angle parameter, the near-field channel model also needs to consider the distance from the antenna element to the scatterer.

[0253] With the development of large-scale antenna arrays, the area of ​​antenna arrays of network equipment has further increased. When the carrier frequency remains unchanged, the Rayleigh distance will increase exponentially with the increase in the area of ​​the antenna array.

[0254] The Rayleigh distance is defined as

[0255] Where r is the Rayleigh distance, D is the area of ​​the antenna array, and λ is the wavelength of the electromagnetic wave.

[0256] As the Rayleigh distance increases, the terminal device is more likely to be in an area that conforms to the laws of spherical waves. Due to the existence of the spherical wavefront, the signal phase at different locations is distorted, increasing the mismatch risk of traditional codebooks.

[0257] For example, traditional codebooks include frequency-domain-angle dual-domain compression codebooks, frequency-domain-angle reciprocity codebooks, and frequency-domain-angle dual-domain compression codebooks that are further compressed in time. These codebooks do not consider the distance dimension. The spatial position determined based on the traditional codebook does not match the actual position of the terminal device, resulting in a decrease in the accuracy of channel estimation.

[0258] The following describes a communication method provided by an embodiment of the present application. As shown in FIG5 , the method 500 includes:

[0259] S510, the terminal device 110 determines a first spatial basis, where the first spatial basis belongs to a spatial basis set, where the spatial basis set includes multiple spatial basis, and each of the multiple spatial basis is determined by the angle and distance of a multipath between the antenna array of the network device 120 and the first object.

[0260] Some features of the first spatial basis and the spatial basis set can be found in the relevant description above and will not be repeated here.

[0261] In the antenna array of network device 120, each antenna can be an antenna that supports switching between left-hand circular polarization and right-hand circular polarization, or an antenna that supports both left-hand circular polarization and right-hand circular polarization, or an antenna that supports linear polarization. The embodiments of the present application do not limit the specific type of antenna array. For example, the antennas in the antenna array can be end-fire circularly polarized antennas, end-ray polarized antennas, edge-fire circularly polarized antennas, or edge-ray polarized antennas. The antennas in the antenna array can be the same or different.

[0262] The first object is the scatterer closest to the antenna array. If the multipath between terminal device 110 and network device 120 is a line-of-sight (LoS) path, the first object is terminal device 110. If the multipath between terminal device 110 and network device 120 is a non-line-of-sight (non-LoS) path, the first object is the scatterer closest to the antenna array. Scatterers can refer to any real-world object in the environment, such as buildings, terrain, and vegetation.

[0263] In the spatial basis set, different spatial basis correspond to different multipaths.

[0264] Before determining the first spatial basis, the terminal device 110 needs to determine a set of candidate distance values, and then determine a set of spatial basis values ​​based on the set of candidate distance values. The following describes an example of a method for the terminal device 110 to determine a set of candidate distance values.

[0265] Method 1 for determining a set of candidate distance values.

[0266] The terminal device 110 determines the maximum value r of the distance between the terminal device and the antenna array. max and the minimum value r min , and the number of quantized bits Δd of the distance between the terminal device 110 and the antenna array; according to r max 、r min and Δd determine a set of distance candidate values.

[0267] r max and r minThe TA may be determined based on the TA of the signal between the antenna array and the terminal device 110. The terminal device 110 may calculate the TA by itself or receive the TA from the network device 120. The terminal device 110 may also directly receive the TA from the network device 120. max and r min .

[0268] For example, the terminal device 110 receives a first signal from the network device 120 and determines the TA of the first signal. The TA of the first signal has an error range, and the upper limit and lower limit of the error range can be used to determine r max and r min .

[0269] For example, the network device 120 receives a first signal from the terminal device 110 and determines the TA of the first signal. The TA of the first signal has an error range. The network device 120 informs the terminal device 110 of the error range. The terminal device 110 can determine r based on the upper and lower limits of the error range. max and r min .

[0270] For example, the network device 120 receives a first signal from the terminal device 110 and determines the TA of the first signal. The TA of the first signal has an error range. Based on the upper limit and lower limit of the error range, r max and r min , then, the network device 120 will r max and r min Notify the terminal device 110.

[0271] Optionally, the terminal device 110 max 、r min When determining the distance candidate value set based on r max 、r min and Δd determine the distance interval d gap According to r max 、r min and d gap Determine a distance candidate value set, where the maximum distance candidate value of the distance candidate value set is r max , the minimum distance candidate value of the distance candidate value set is r min , the difference between any two distance candidate values ​​in the distance candidate value set is d gap An integer multiple of .

[0272] Optionally, Among them, d gap It can be obtained from the network device 120.

[0273] The difference between any two distance candidate values ​​in the distance candidate value set is d gapAn integer multiple of indicates that the intervals between two adjacent distance candidate values ​​in the distance candidate value set are equal.

[0274] For example, the distance candidate value set r can be {r min ,r min +d gap ,r min +2d gap ,…,r max}, where r min and r min +d gap are two adjacent distance candidate values, r min +d gap and r min +2d gap are two adjacent distance candidate values.

[0275] Method 2 for determining a set of candidate distance values.

[0276] Determine the maximum value r of the distance between the terminal device 110 and the antenna array max and the minimum value r min , and the distance interval d gap According to r max 、r min and d gap Determine the distance candidate value set, the maximum distance candidate value of the distance candidate value set is r max , the minimum distance candidate value of the distance candidate value set is r min , the difference between two adjacent distance candidate values ​​in the distance candidate value set is d gap , d gap There is a correlation relationship between the distance between the terminal device 110 and the antenna array.

[0277] In the second method for determining the distance candidate value set, the terminal device 110 determines r max and r min Method and method for determining distance candidate value set: determining r max and r min The method is the same and will not be repeated here.

[0278] The terminal device 110 can obtain d from the network device 120 gap .

[0279] For example, the network device 120 may send d values ​​corresponding to different distances to the terminal device 110. gap , the terminal device 110 receives d corresponding to different distances gap Afterwards, according to r min Determine the corresponding interval d gap1 , then calculate r min with dgap1 The sum of , we get r min +d gap1 Then the terminal device 110 is based on r min +d gap1 The corresponding interval d gap2 , then calculate r min +d gap1 with d gap2 The sum of , we get r min +d gap1 +d gap2 ; and so on, until the calculated value is closest to r max The candidate distance value r min +d gap1 +d gap2 +…+d gapn So far, we get the distance candidate value set r, which can be {r min ,r min +d gap1 ,r min +d gap1 +d gap2 ,…,r min +d gap1 +d gap2 +…+d gapn ,r max}.

[0280] For another example, the network device 120 may send d to the terminal device 110. gap The function that changes with distance (or "variation relationship"). After receiving the function, the terminal device 110 min And the function determines the corresponding interval d gap1 , then calculate r min with d gap1 The sum of , we get r min +d gap1 Then the terminal device 110 is based on r min +d gap1 And the function determines the corresponding interval d gap2 , then calculate r min +d gap1 with d gap2 The sum of , we get r min +d gap1 +d gap2 ; and so on, until the calculated value is closest to r max The candidate distance value r min +d gap1 +d gap2 +…+d gapn So far, we get the distance candidate value set r, which can be {r min ,r min+d gap1 ,r min +d gap1 +d gap2 ,…,r min +d gap1 +d gap2 +…+d gapn ,r max}.

[0281] In the distance candidate value set r obtained based on the second method for determining the distance candidate value set, the intervals between two adjacent distance candidate values ​​are different, that is, d gap1 with d gap2 different.

[0282] After determining the distance candidate value set, the terminal device 110 may determine the angle candidate value set, and determine the spatial basis set according to the distance candidate value set and the angle candidate value set.

[0283] For example, the terminal device 110 may determine the angle candidate value set according to 3GPP TS 38.214 V16.4.0 (2020-12). When the antenna array is a planar array, the terminal device 110 may determine the spatial basis set according to formula (1) and formula (2).

[0284] In formula (1), Ω i is the angular distance fusion parameter of the i-th vibrator in the antenna array, d is the multipath distance from the reference vibrator in the antenna array to the nearest scatterer (i.e., the value in the distance candidate value set), is the multipath angle (i.e., a value in the angle candidate value set), r i is the position of the i-th element in the antenna array, is the position of the reference vibrator, where the i-th vibrator is any vibrator in the antenna array, the reference vibrator can be the vibrator with the shortest distance to the nearest scatterer among the vibrators in the antenna array, and i is a positive integer.

[0285] In formula (2), a i is the spatial basis of the i-th oscillator in the antenna array (also called the steering vector), e is a natural constant, j is the imaginary part, f is the carrier frequency, c is the speed of light, n is the number of columns of the i-th oscillator, m is the number of rows of the i-th oscillator, d x is the horizontal spacing of the elements in the antenna array, d y is the vertical spacing of the antenna array elements, Ω x Ω i The component in the horizontal dimension, Ω y Ω i Component in the vertical dimension. dx and d y It can be obtained from the network device 120, or it can be equal to half the wavelength by default.

[0286] The terminal device 110 can obtain the number of oscillators N1 in the horizontal dimension and the number of oscillators N2 in the vertical dimension of the antenna array from the network device 120, and calculate the Ω of each oscillator. i and a i , Ω of all oscillators i The set formed is the angle basis set, and the a of all oscillators i The set formed is the spatial basis set.

[0287] It should be understood that the above method for determining the spatial basis set is an example and not a limitation. After the terminal device 110 determines the spatial basis set, it can determine the first spatial basis from the spatial basis set.

[0288] Optionally, the antenna array may be divided into multiple sub-arrays, and the terminal device 110 may determine the first spatial basis based on the sub-arrays.

[0289] For example, the antenna array may be divided into a first sub-array and a second sub-array, and the terminal device 110 determines the first received data, the second received data, and the max 、r min and δ, wherein the first received data is the data from the first subarray, the second received data is the data from the second subarray, r min is the maximum distance between the terminal device 110 and the antenna array, r min is the minimum distance between the terminal device 110 and the antenna array, δ is the distance between the first subarray and the second subarray; the terminal device 110 processes the first received data, the second received data, and r through dictionary learning min 、r min and δ, the angle basis of the first subarray, the distance basis of the first subarray, the angle basis of the second subarray, and the distance basis of the second subarray are obtained.

[0290] The dictionary learning algorithm is as follows.

[0291] The relationship between the channel, dictionary and transmitted signal is as follows: h(x,y)=W(r)s;

[0292] Where h(x,y) represents the channel and W(r) represents the dictionary used for channel estimation ， That is, the angle basis set and the distance basis set, s represents the transmitted signal.

[0293] The dimension of the dictionary can be defined as N*N, then W(r)=[b N (θ1,r1),b N (θ2,r2),…,bN (θ N ,r N )];

[0294] Among them, b N represents the steering vector, θ1 to θ N Represents the candidate values ​​of the multipath angles from N subarrays to the nearest scatterer, r1 to r N represents the candidate values ​​of the multipath distances from the N subarrays to the nearest scatterer. As shown in Figure 6, θ1 represents the candidate value of the multipath angle from the first subarray to the nearest scatterer, θ2 represents the candidate value of the multipath angle from the second subarray to the nearest scatterer, r1 represents the candidate value of the multipath distance from the first subarray to the nearest scatterer, r2 represents the candidate value of the multipath distance from the second subarray to the nearest scatterer, and δ represents the spacing between the first and second subarrays.

[0295] After the antenna array is divided into the first subarray and the second subarray, the transmitted signal s can also be divided into two parts. Accordingly, the two signals received by the terminal device 110 are y1 and y2, where y1 is the first received data and y2 is the second received data.

[0296] For each iteration of each multipath, the following process occurs:

[0297] The terminal device 110 uses r max Calculate the initial dictionaries W1(r) and W2(r) for all angles;

[0298] Estimate θ1 based on W1(r), where is the estimated value of θ1;

[0299] according to Determine d1 and d2, and determine θ based on d1 min , determine θ based on d2 max ; According to θ min and θ max Select some elements from W2(r) as sub-dictionary W 2,sub (r), where

[0300] According to W 2,sub (r) Estimate θ2, where is the estimated value of θ2;

[0301] According to the geometric relationship shown in Figure 6, r1 and r2 are calculated, where

[0302] is the estimated value of r1, is the estimated value of r2;

[0303] according to Update the columns of W1(r) according to Update the columns of W2(r).

[0304] Repeat the above steps until the iteration is terminated to obtain updated W1(r) and updated W2(r). Multipath parameters such as delay, angle, and distance are calculated based on the updated W1(r) and updated W2(r).

[0305] Dictionary learning can be used to obtain the multipath delays, multipath angles, multipath distances, and combining coefficients estimated by the first subarray, as well as the multipath delays, multipath angles, multipath distances, and combining coefficients estimated by the second subarray. Spatial domain basis (including distance basis and angle basis) and frequency domain basis can be calculated based on the multipath angles and multipath distances.

[0306] It should be noted that each sub-array includes at least one transducer, and the number of transducers included in each sub-array may be the same or different.

[0307] After the terminal device 110 determines the angle basis and the distance basis of the first subarray, and the angle basis and the distance basis of the second subarray, it can report them in the following ways:

[0308] Reporting method 1: τ, r1, θ1 and α1.

[0309] Reporting method 2: τ, r2, θ2 and α2.

[0310] Reporting method three: τ, r1, θ1, α1 and α2.

[0311] Reporting method four: τ, r2, θ2, α1 and α2.

[0312] Reporting method five: τ, r1, θ1, r2, θ2, α1 and α2.

[0313] τ is the index of the frequency basis shared by the first and second subarrays, r1 is the index of the range basis of the first subarray, r2 is the index of the range basis of the second subarray, θ1 is the index of the angle basis of the first subarray, θ2 is the index of the angle basis of the second subarray, α1 is the combination coefficient of the first subarray, and α2 is the combination coefficient of the second subarray.

[0314] The network device 120 can deduce the angle basis and distance basis of the second subarray based on the geometric relationship shown in FIG6 and the angle basis and distance basis of the first subarray, or the network device 120 can deduce the angle basis and distance basis of the first subarray based on the geometric relationship shown in FIG6 and the angle basis and distance basis of the second subarray. Therefore, the terminal device 110 can reduce the feedback overhead by using reporting methods one to four. In addition, if it is believed that the combination coefficients of the same multipath are the same, α1 is equal to α2, and the terminal device 110 can further reduce the feedback overhead by using reporting methods one and two. If it is believed that the combination coefficients of the same multipath are different, α1 is not equal to α2, and the terminal device 110 can use reporting methods three to five.

[0315] In the example of determining the spatial basis based on dictionary learning, the first spatial basis includes: the angle basis of the first subarray, and the distance basis of the first subarray; and / or the angle basis of the second subarray, and the distance basis of the second subarray.

[0316] After dividing the antenna array into multiple subarrays, terminal device 110 can estimate the basis of each subarray separately and then jointly feed back the PMIs of the multiple subarrays to network device 120. Network device 120 can then reconstruct the channel based on the geometric relationship between the multiple subarrays and the PMIs of the multiple subarrays. Because the amount of received data that terminal device 110 needs to process when estimating the basis of a subarray is reduced, the number of distance and angle loop nestings in the dictionary learning process is reduced, thereby reducing the complexity and power consumption of channel estimation performed by terminal device 110.

[0317] After the terminal device 110 determines the first spatial basis, it can perform the following steps.

[0318] S520: Determine a combination coefficient according to the first spatial basis.

[0319] The terminal device 110 may determine the combination coefficient based on steps 1 and 2 described below.

[0320] Step 1: The terminal device 110 performs space-frequency joint covariance matrix statistics on the downlink channel and performs inter-polarization averaging to obtain right Perform SVD or eigendecomposition to obtain the matrix of eigenvectors Pair Matrix Cut off and select the one with larger energy The corresponding eigenvalues Columns constitute the statistical feature matrix Contains most of the energy of the channel (P can be determined by the terminal device 110 itself, or the network device 120 specifies an optional range and the terminal device 110 selects P from the range).

[0321] Step 2: The terminal device 110 uses the DFT codebook to construct a statistical feature matrix of the statistical feature vector Make an approximation, that is, find W f 、W s and W2, such that or Among them, W f and W s is a submatrix composed of some columns of the oversampled DFT matrix, W f represents the frequency domain basis, W s represents the spatial basis (e.g., the first spatial basis described above); W2 represents the combination coefficient matrix, which is The projection on the spatial compression matrix W1, therefore, the process of determining W2 is to find a matrix that can correct W1 to The process of the matrix.

[0322] Steps 1 and 2 are examples and not limitations. This application does not limit the method for determining the combination coefficient based on the first spatial basis. After determining the combination coefficient, the terminal device 110 may perform the following steps.

[0323] S530: Send PMI, where the PMI includes an identifier of the first spatial basis and a combination coefficient.

[0324] Accordingly, network device 120 receives the PMI.

[0325] Each spatial basis in the spatial basis set has a corresponding identifier (also called an "index"). The terminal device 110 can report the index of one or more selected spatial basis to the network device 120 through PMI. The one or more spatial basis includes the first spatial basis.

[0326] Optionally, the index of the first spatial basis may include an identifier of the angle basis corresponding to the first spatial basis and an identifier of the distance basis corresponding to the first spatial basis. Optionally, the PMI also includes an oversampling rate of the angle basis corresponding to the first spatial basis and an oversampling rate of the distance basis corresponding to the first spatial basis.

[0327] The elements in W2 are the combination coefficients corresponding to all spatial basis, and the terminal device 110 can select all or part of the combination coefficients and report them to the network device 120. For example, the terminal device 110 can report the non-zero coefficients and the strongest coefficients among all the combination coefficients to the network device 120 through the PMI, where the non-zero coefficients can be indicated by a bitmap with a bit number of 2*L*D*M, where L is the number of angle basis corresponding to all spatial basis in the spatial basis set, D is the number of distance basis corresponding to all spatial basis in the spatial basis set, and M is the number of all frequency domain basis.

[0328] A bitmap with a bit count of 2*L*D*M is suitable for scenarios that include angle basis, range basis, and frequency basis. The oversampling rate of the range basis can be used to expand the number of range basis, and thus the number of spatial basis in the spatial basis set. A larger set of spatial basis allows network equipment to recover a precoding matrix that is closer to the precoding matrix determined by the terminal device, thereby improving channel estimation accuracy.

[0329] Optionally, the PMI also includes other information, such as the number of non-zero coefficients, RI, CQI, the index of the frequency domain basis, and the oversampling rate of the frequency domain basis, etc. The embodiment of the present application does not limit the information included in the PMI.

[0330] After receiving the PMI, the network device 120 may perform the following steps.

[0331] S540: Determine the first spatial basis from the spatial basis set according to the identifier of the first spatial basis.

[0332] S550: Determine a precoding matrix according to the first spatial basis and the combination coefficients.

[0333] Network device 120 determines one or more spatial basis sets from a spatial basis set based on the spatial basis index in the PMI. The one or more spatial basis sets include a first spatial basis. The one or more spatial basis sets comprise a spatial compression matrix W1. Network device 120 determines one or more combining coefficients based on the PMI. The one or more combining coefficients comprise a combining coefficient matrix W2. Network device 120 determines one or more frequency basis sets from a frequency basis set based on the frequency basis index in the PMI. The one or more frequency basis sets comprise a frequency compression matrix W3.

[0334] Subsequently, the network device 120 may determine the precoding matrix W according to W1, W2, W3 and the near-field codebook structure shown in formula (3).

[0335] In formula (3), Where P is the number of antenna ports, L is the number of spatial basis, D is the number of distance basis, M is the number of frequency domain basis, N3 is the number of frequency domain elements, and the dimension of the precoding matrix W is P×N3.

[0336] It should be noted that the network device 120 has determined the spatial basis set before executing S540. The method for the network device 120 to determine the spatial basis set can refer to the method for the terminal device 110 to determine the spatial basis set, which will not be repeated here.

[0337] As the Rayleigh distance increases, the terminal device 110 is more likely to be in an area that conforms to the law of spherical waves. Due to the existence of the spherical wave front, the signal phases at different positions are distorted. Therefore, when performing precoding, it is necessary to consider the distance from the antenna element to the scatterer, that is, the multipath distance needs to be considered. In method 500, each spatial basis in the spatial basis set takes into account the angle and distance of the multipath at the same time, and the codebook set based on the spatial basis set is more in line with the law of spherical waves. Therefore, the PMI sent by the terminal device 110, which includes the identifier of the first spatial basis and the combination coefficient, can match the spatial position determined by the network device 120 with the actual position of the terminal device, thereby improving the accuracy of channel estimation.

[0338] The above describes the process of method 500 .

[0339] Optionally, in method 500, the signaling interaction process of the terminal device 110 feeding back the PMI based on formula (1) and formula (2) is shown in FIG7 .

[0340] S710 , the network device 120 sends parameters required for feedback of the PMI to the terminal device 110 .

[0341] The parameters required for PMI feedback include: max 、r min , Δd, N1 and N2. The parameters required for feeding back the PMI may also include other parameters, such as the horizontal spacing of the elements in the antenna array and the vertical spacing of the elements in the antenna array, which are not limited here.

[0342] S720: The terminal device 110 determines a spatial domain basis, a frequency domain basis, and a combination coefficient according to parameters required for feedback of the PMI.

[0343] According to r max 、r min The method for determining the spatial basis and the combination coefficient using Δd, N1 and N2 is as described above. The method for determining the frequency domain basis can refer to the relevant methods in the prior art and will not be repeated here.

[0344] S730 , the terminal device 110 sends the PMI to the network device 120 .

[0345] The PMI includes the index of the spatial basis, the index of the frequency basis, and the combination coefficient. The PMI may also include the number of non-zero coefficients, RI, CQI, and the oversampling rate of the frequency basis, etc. The present embodiment does not limit the information contained in the PMI.

[0346] S740: The network device 120 determines a precoding matrix according to the PMI.

[0347] The method for determining the precoding matrix according to the PMI is as described in S550 and will not be repeated here.

[0348] Optionally, in method 500 , a signaling interaction process of the terminal device 110 feeding back PMI based on multiple sub-arrays is shown in FIG8 .

[0349] S810 , the network device 120 sends parameters required for feedback of the PMI to the terminal device 110 .

[0350] The parameters required for PMI feedback include: max 、r min , and the spacing between each subarray (eg, δ). The parameters required for PMI feedback may also include other parameters, such as the number of transducers in each subarray, which are not limited here.

[0351] S820: The terminal device 110 determines a spatial domain basis, a frequency domain basis, and a combination coefficient according to parameters required for feedback of the PMI.

[0352] The terminal device 110 may determine the spatial domain basis, the frequency domain basis, and the combination coefficient according to the dictionary learning algorithm described above and the parameters required for feeding back the PMI.

[0353] For example, the terminal device 110 processes the first received data, the second received data, and the min 、r min and δ, the angle basis of the first subarray, the distance basis of the first subarray, the angle basis of the second subarray, and the distance basis of the second subarray are obtained.

[0354] S830 , the terminal device 110 sends the PMI to the network device 120 .

[0355] The PMI includes the index of the spatial basis of one or more subarrays, the index of the frequency basis, and the combination coefficients. The PMI may also include the number of non-zero coefficients, RI, CQI, and the oversampling rate of the frequency basis, etc. The present embodiment does not limit the information contained in the PMI.

[0356] S840: The network device 120 determines a precoding matrix according to the PMI.

[0357] The method for determining the precoding matrix according to the PMI is as described in S550 and will not be repeated here.

[0358] The above describes in detail the method for determining the precoding matrix in the scenario of a near-field channel model. Optionally, terminal device 110 and network device 120 can determine whether the current scenario is applicable to a near-field channel model or a far-field channel model before executing method 500. Terminal device 110 can determine the applicable channel model for the current scenario using the following two methods.

[0359] Method 1 for determining the target channel model.

[0360] Determine the distance d between the terminal device 110 and the antenna array TA According to d TA Determine a target channel model, where the target channel model is a first channel model or a second channel model, wherein, in the first channel model, distances from each vibrator in the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; determine a first spatial basis, including: when the target channel model is the first channel model, determine the first spatial basis.

[0361] The first channel model is a near-field channel model, and the second channel model is a far-field channel model. The terminal device 110 can determine the TA of the first signal and determine the d according to the TA of the first signal. TA .

[0362] TA is a parameter used to maintain uplink time synchronization. In order for the terminal device 110 to communicate with the network device 120, uplink time synchronization and downlink time synchronization are required. After the terminal device 110 is turned on, it will search for a cell and obtain downlink time synchronization through the primary synchronization signal and secondary synchronization signal broadcast by the cell. Any uplink signal can be used as input for uplink timing measurement by the physical layer. For example, the uplink signals used by the physical layer for uplink timing measurement can be: random access (RA) preamble, SRS, DMRS and physical uplink control channel (PUCCH).

[0363] When the terminal device 110 performs random access, the physical layer will obtain the uplink timing value based on the RA preamble code measurement and report the measured TA to L2; the timing maintenance after the terminal device 110 successfully performs random access can be performed through SRS or PUCCH, and when there is uplink data transmission, DMRS can also be used to obtain the uplink timing measurement offset value.

[0364] TA can reflect the distance between the network device 120 and the terminal device 110. The distance d is calculated based on TA.TA The method is as follows: d TA =TA*c / 2, c is the speed of light.

[0365] The network device 120 may obtain the TA by measuring the first signal, and send the TA to the terminal device 110 through the first indication information. Optionally, when the multiple signals between the terminal device 110 and the network device 120 include a random access preamble, an SRS, and a DMRS, the first signal may be an SRS; or, when the multiple signals between the terminal device 110 and the network device 120 include a random access preamble and a DMRS, the first signal may be a DMRS.

[0366] The TA measured by SRS is more accurate than the TA measured by DMRS or random access preamble, and the TA measured by DMRS is more accurate than the TA measured by random access preamble. Therefore, by selecting the first signal based on the above priority, a more accurate TA can be obtained, thereby making the target channel model determined based on TA more accurate.

[0367] The network device 120 can also measure multiple signals to obtain multiple TAs, send the multiple TAs to the terminal device 110, and use one of the TAs in the first indication information. The terminal device 110 calculates d according to the TA indicated by the first indication information. TA .

[0368] The network device 120 can also calculate d TA , d TA Sent to the terminal device 110.

[0369] In accordance with d TA Before determining the target channel model, the terminal device 110 may also determine d FF , d FF is the distance from each vibrator in the antenna array to the first object in the second channel model, where d FF =2D 2 / λ, where D is the area of ​​the antenna array and λ is the wavelength of the electromagnetic wave. The network device 120 calculates d FF Then d FF Then, the terminal device 110 can TA with d FF Alternatively, the terminal device 110 can determine the target channel model based on the absolute value of the difference between d TA with d FF The target channel model is determined by the ratio of .

[0370] For example, if |d TA -d FF|<first distance threshold, the terminal device 110 determines that the target channel model is the first channel model; if |d TA -d FF |>second distance threshold, the terminal device 110 determines that the target channel model is the second channel model; wherein the first distance threshold is less than or equal to the second distance threshold, and the first distance threshold and the second distance threshold can be obtained from the network device 120.

[0371] For example, if d TA / d FF <third distance threshold, the terminal device 110 determines that the target channel model is the first channel model; if d TA / d FF >fourth distance threshold, the terminal device 110 determines that the target channel model is the second channel model; wherein the third distance threshold is less than or equal to the fourth distance threshold, and the third distance threshold and the fourth distance threshold can be obtained from the network device 120.

[0372] After determining the target channel model, the terminal device 110 may inform the network device 120 of the target channel model through the third indication information, so that the network device 120 can reconstruct a more accurate precoding matrix based on the target channel model.

[0373] Optionally, the network device 120 may TA with d FF The absolute value of the difference or according to d TA with d FF The target channel model is determined by the ratio of , and then the network device 120 notifies the terminal device 110 of the target channel model through the fourth indication information. The terminal device 110 does not need to determine the target channel model through local calculation, thereby reducing the power consumption of the terminal device 110 in determining the target channel model.

[0374] The above describes the method for the terminal device 110 and the network device 120 to determine the target channel model.

[0375] Optionally, the terminal device 110 TA The signaling interaction process of the method for determining the target channel model is shown in FIG9 .

[0376] S910 , the terminal device 110 sends a first signal to the network device 120 .

[0377] The first signal may be at least one of the random access preamble, SRS, and DMRS described above. The first signal may also be other uplink signals capable of measuring TA, such as PUCCH.

[0378] S920: The network device 120 measures TA through the first signal.

[0379] S930 , the network device 120 sends a TA to the terminal device 110 .

[0380] If the network device 120 measures the TAs of multiple signals, the network device 120 may send the priorities of the TAs of the multiple signals to the terminal device 110 when sending the TAs. Optionally, the priority may also be a preset priority. Optionally, the network device 120 may not send the priority, but directly instruct the terminal device 110 to use one of the TAs of the multiple signals, for example, by indicating the TA of the first signal through first indication information, wherein the first indication information may be a 2-bit field; the first indication information of 00 may indicate the TA of the random access preamble, the first indication information of 01 may indicate the TA of the SRS, the first indication information of 10 may indicate the TA of the DMRS, and the first indication information of 11 may indicate the TA of the PUCCH.

[0381] S940, the terminal device 110 determines d according to the TA TA .

[0382] The terminal device 110 can determine a TA according to the priority or the instruction of the network device 120, and calculate d according to the TA. TA .

[0383] S950, the network device 120 sends d to the terminal device 110 FF and distance threshold.

[0384] The distance threshold can be:

[0385] a first distance threshold, and a second distance threshold; and / or

[0386] A third distance threshold, and, a fourth distance threshold.

[0387] If the first distance threshold is equal to the second distance threshold, the network device 120 may only send one of them; if the third distance threshold is equal to the fourth distance threshold, the network device 120 may only send one of them. FF The distance threshold can be carried in one message or in multiple messages. FF There is no limitation on the specific message of the distance threshold.

[0388] S950 can be executed at any time before S960, for example, before S930, after S930, or simultaneously with S930, that is, the network device 120 sends TA, d FF and the distance threshold are sent to the terminal device 110.

[0389] Optionally, the distance threshold may be a preset value, such as a value specified by a protocol, or a value configured by a manufacturer. In this case, the network device 120 no longer sends the distance threshold.

[0390] S960, the terminal device 110 receives the data according to the d TA d FF and distance threshold to determine the target channel model.

[0391] If the distance threshold includes a first distance threshold and a second distance threshold, the terminal device 110 can TA with d FF The target channel model is determined based on the absolute value of the difference between the first and second distance thresholds.

[0392] If the distance threshold includes a third distance threshold and a fourth distance threshold, the terminal device 110 can TA with d FF The target channel model is determined based on the ratio of , the third distance threshold and the fourth distance threshold.

[0393] If the distance threshold includes a first distance threshold, a second distance threshold, a third distance threshold, and a fourth distance threshold, the terminal device 110 may independently decide which distance thresholds to use to determine the target channel model.

[0394] S970 , the terminal device 110 indicates the target channel model to the network device 120 .

[0395] For example, the terminal device 110 can indicate the target channel model to the network device 120 through the third indication information, where the third indication information can be a 1-bit field; the third indication information is 0, which can indicate that the target channel model is the first channel model; the third indication information is 1, which can indicate that the target channel model is the second channel model.

[0396] Optionally, the network device 120 may be configured to: TA The signaling interaction process of the method for determining the target channel model is shown in FIG10 .

[0397] S1010 , the terminal device 110 sends a first signal to the network device 120 .

[0398] The first signal may be at least one of the random access preamble, SRS, and DMRS described above. The first signal may also be other uplink signals capable of measuring TA, such as PUCCH.

[0399] S1020: The network device 120 measures TA through the first signal.

[0400] S1030, the network device 120 determines d according to the TA TA .

[0401] If the first signal includes multiple signals, the network device 120 can determine which signal's TA to use. TA For example, the network device 120 may determine the TA using the SRS according to the priorities of the random access preamble, SRS, and DMRS. TA .

[0402] S1040, the network device 120 receives the data according to the d TA d FF and distance threshold to determine the target channel model.

[0403] If the distance threshold includes a first distance threshold and a second distance threshold, the network device 120 can TA with d FF The target channel model is determined based on the absolute value of the difference between the first and second distance thresholds.

[0404] If the distance threshold includes a third distance threshold and a fourth distance threshold, the network device 120 can TA with d FF The target channel model is determined based on the ratio of , the third distance threshold and the fourth distance threshold.

[0405] If the distance threshold includes a first distance threshold, a second distance threshold, a third distance threshold, and a fourth distance threshold, the network device 120 may independently determine which distance thresholds to use to determine the target channel model.

[0406] S1050 , the network device 120 indicates the target channel model to the terminal device 110 .

[0407] For example, the network device 120 can indicate the target channel model to the terminal device 110 through the fourth indication information, where the fourth indication information can be a 1-bit field; the fourth indication information is 0, which can indicate that the target channel model is the first channel model; the fourth indication information is 1, which can indicate that the target channel model is the second channel model.

[0408] Method 2 for determining the target channel model.

[0409] Determine the trace of the spatial correlation matrix of the antenna array cur According to tra cur Determine a target channel model, where the target channel model is a first channel model or a second channel model, wherein, in the first channel model, distances from each vibrator in the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; determine a first spatial basis, including: when the target channel model is the first channel model, determine the first spatial basis.

[0410] tra cur is the trace of the spatial correlation matrix of the current antenna array, the terminal device 110 can calculate the average value of the trace of the spatial correlation matrix of multiple time units and use the average value as tra cur To reduce tra cur The time unit is, for example, a transmission time interval (TTI) or a time slot. The embodiment of the present application does not limit the specific type of the time unit.

[0411] In accordance with tra cur Before determining the target channel model, the terminal device 110 may also determine the tra ref ,tra ref is the trace of the spatial correlation matrix corresponding to the second channel model. The network device 120 can calculate tra ref , through the second instruction information, tra ref Notify the terminal device 110.

[0412] Optionally, tra ref is the default value, or, ref is the average value of the trace of the spatial correlation matrix of multiple terminal devices applying the second channel model. ref The method is not limited.

[0413] Determine the cur and tra ref After that, the terminal device 110 can cur With tra ref The target channel model can be determined by the absolute value of the difference between cur With tra ref The target channel model is determined by the ratio of .

[0414] For example, if |tra cur -tra ref |>first trace threshold, the terminal device 110 determines that the target channel model is the first channel model; if |tra cur -tra ref |<second trace threshold, the terminal device 110 determines that the target channel model is the second channel model; wherein the first trace threshold is greater than or equal to the second trace threshold, and the first trace threshold and the second trace threshold can be obtained from the network device 120.

[0415] For example, if tra cur / tra ref > the third trace threshold, the terminal device 110 determines that the target channel model is the first channel model; if tra cur / tra ref <fourth trace threshold, the terminal device 110 determines that the target channel model is the second channel model; wherein the third trace threshold is greater than or equal to the fourth trace threshold, and the third trace threshold and the fourth trace threshold can be obtained from the network device 120.

[0416] After determining the target channel model, the terminal device 110 may inform the network device 120 of the target channel model through the third indication information, so that the network device 120 can reconstruct a more accurate precoding matrix based on the target channel model.

[0417] Optionally, the network device 120 may be configured to cur With tra ref The absolute value of the difference or according to tra cur With tra ref The target channel model is determined by the ratio of , and then the network device 120 notifies the terminal device 110 of the target channel model through the fourth indication information. The terminal device 110 does not need to determine the target channel model through local calculation, thereby reducing the power consumption of the terminal device 110 in determining the target channel model.

[0418] Different bandwidth parts (BWPs) can share the above-mentioned target channel model determination and various indication information. In carrier aggregation (CA) scenarios, similar frequency bands can also share the above-mentioned target channel model determination and various indication information.

[0419] For example, after the terminal device 110 determines the target channel model of BWP1, it can determine that the target channel model of BWP2 is the target channel model of BWP1; after the terminal device 110 informs the network device 120 of the target channel model of BWP1 through the third indication information, the network device 120 can determine that the target channel model of BWP2 is the target channel model of BWP1 according to the third indication information.

[0420] For another example, after network device 120 determines the target channel model of frequency band 1, it can determine that the target channel model of frequency band 2 is the target channel model of frequency band 1. After terminal device 110 notifies terminal device 110 of the target channel model of frequency band 1 through fourth indication information, terminal device 110 can determine, based on the third indication information, the target channel model of frequency band 2 as the target channel model of frequency band 1. Frequency band 1 and frequency band 2 are frequency bands corresponding to two aggregated carriers, and the frequencies of frequency band 1 and frequency band 2 are similar.

[0421] Optionally, the terminal device 110 cur The signaling interaction process of the method for determining the target channel model is shown in FIG11 .

[0422] S1110, the network device 120 sends a tra ref and trace threshold.

[0423] The trace threshold can be:

[0424] A first trace threshold, and a second trace threshold; and / or

[0425] The third trace threshold,and,the fourth trace threshold.

[0426] If the first trace threshold is equal to the second trace threshold, the network device 120 may only send one of them; if the third trace threshold is equal to the fourth trace threshold, the network device 120 may only send one of them. ref The trace threshold can be carried in one message or in multiple messages. ref There is no limitation on the specific message of the trace threshold.

[0427] Network device 120 calculates tra ref After that, you can use the second instruction information to ref Notify the terminal device 110.

[0428] S1120, the terminal device 110 determines the cur .

[0429] The terminal device 110 may calculate the average value of the trace of the spatial correlation matrix of multiple time units and use the average value as the tra cur To reduce tra cur The time unit is, for example, a TTI or a time slot. The embodiment of the present application does not limit the specific type of the time unit.

[0430] S1130, the terminal device 110 receives the data according to the tra cur 、tra ref The target channel model is determined by summing the trace threshold.

[0431] If the trace threshold includes a first trace threshold and a second trace threshold, the terminal device 110 may cur With tra cur The target channel model is determined based on the absolute value of the difference between the first trace threshold and the second trace threshold.

[0432] If the trace threshold includes a third trace threshold and a fourth trace threshold, the terminal device 110 may cur With tra cur The target channel model is determined by the ratio of , the third trace threshold and the fourth trace threshold.

[0433] If the trace thresholds include a first trace threshold, a second trace threshold, a third trace threshold, and a fourth trace threshold, the terminal device 110 may independently determine which trace thresholds to use to determine the target channel model.

[0434] S1140 , the terminal device 110 indicates the target channel model to the network device 120 .

[0435] For example, the terminal device 110 can indicate the target channel model to the network device 120 through the third indication information, where the third indication information can be a 1-bit field; the third indication information is 0, which can indicate that the target channel model is the first channel model; the third indication information is 1, which can indicate that the target channel model is the second channel model.

[0436] The above describes in detail the method examples provided by the embodiments of the present application. It is understandable that, in order to implement the above functions, the corresponding device includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should easily appreciate that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in a hardware or computer software driven hardware manner depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0437] Figures 12 and 13 are schematic diagrams of the structures of two possible communication devices provided in embodiments of the present application. These communication devices can be used to implement the functions of the terminal device 110 or the network device 120 in the above-mentioned method embodiments, and therefore also have the beneficial effects of the above-mentioned method embodiments. In the embodiments of the present application, these communication devices can be the terminal device 110 shown in Figure 1, the network device 120 described in Figure 1, or a model (e.g., a chip) applied to the terminal device 110 or the network device 120.

[0438] As shown in Figure 12, the communication device 1200 includes a processing unit 1210 and a transceiver unit 1220. The transceiver unit 1220 performs a receiving step and / or a sending step under the control of the processing unit 1210, wherein the transceiver unit 1220 is a sending unit when performing the sending step and a receiving unit when performing the receiving step.

[0439] The communication device 1200 is used to implement the functions of the terminal device 110 or the network device 120 in the method embodiments described in Figures 5, 7, 8, 9, 10 or 11 above.

[0440] When the communication device 1200 is used to implement the functions of the terminal device 110, the processing unit 1210 is used to: determine a first spatial basis, the first spatial basis belongs to a spatial basis set, the spatial basis set includes multiple spatial basis, each of the multiple spatial basis is determined by the angle and distance of a multipath between the antenna array of the network device and the first object; determine the combination coefficient according to the first spatial basis; the transceiver unit 1220 is used to: send PMI, the PMI includes the identifier of the first spatial basis and the combination coefficient.

[0441] Optionally, before determining the first spatial basis, the processing unit 1210 is further configured to: determine the maximum value r of the distance between the terminal device and the antenna array. max and the minimum value r min , and the quantized number of bits Δd of the distance between the terminal device and the antenna array; according to r max 、r min and Δd to determine a distance candidate value set; determine an angle candidate value set; and determine a spatial basis set based on the distance candidate value set and the angle candidate value set.

[0442] Optionally, the processing unit 1210 is specifically configured to: max 、r min and Δd determine the distance interval d gap According to r max 、r min and d gap Determine the distance candidate value set, the maximum distance candidate value of the distance candidate value set is r max , the minimum distance candidate value of the distance candidate value set is r min , the difference between any two distance candidate values ​​in the distance candidate value set is d gap An integer multiple of .

[0443] Optionally, before determining the first spatial basis, the processing unit 1210 is further configured to: determine the maximum value r of the distance between the terminal device and the antenna array. max and the minimum value r min , and the distance interval d gap According to r max 、r min and d gap Determine the distance candidate value set, the maximum distance candidate value of the distance candidate value set is r max , the minimum distance candidate value of the distance candidate value set is r min , the difference between two adjacent distance candidate values ​​in the distance candidate value set is d gap , d gap There is a correlation relationship between the distance between the terminal device and the antenna array; determining a set of angle candidate values; and determining a spatial basis set based on the distance candidate value set and the angle candidate value set.

[0444] Optionally, the antenna array includes a first subarray and a second subarray, and the processing unit 1210 is specifically configured to: determine the first received data, the second received data, r max 、r min and δ, wherein the first received data is the data from the first subarray, the second received data is the data from the second subarray, r min is the maximum distance between the terminal device and the antenna array, r min is the minimum distance between the terminal device and the antenna array, δ is the distance between the first subarray and the second subarray; the first received data, the second received data, r are processed by dictionary learning. min 、r min and δ, to obtain the angle basis of the first subarray, the distance basis of the first subarray, the angle basis of the second subarray, and the distance basis of the second subarray; wherein the first spatial basis includes: the angle basis of the first subarray and the distance basis of the first subarray; and / or the angle basis of the second subarray and the distance basis of the second subarray.

[0445] Optionally, before determining the first spatial basis, the processing unit 1210 is further configured to: determine a distance d between the terminal device and the antenna array TA According to d TA Determine a target channel model, where the target channel model is a first channel model or a second channel model, wherein, in the first channel model, distances from each vibrator in the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; determine a first spatial basis, including: when the target channel model is the first channel model, determine the first spatial basis.

[0446] Optionally, the processing unit 1210 is specifically configured to: determine d FF , d FF is the distance from each vibrator in the antenna array to the first object in the second channel model; if d TA with d FF The absolute value of the difference between the two is less than the first distance threshold, and the target channel model is determined to be the first channel model; if d TA with d FF The absolute value of the difference between is greater than the second distance threshold, and the target channel model is determined to be the second channel model; wherein the first distance threshold is less than or equal to the second distance threshold.

[0447] Optionally, the processing unit 1210 is specifically configured to: determine d FF , d FF is the distance from each vibrator in the antenna array to the first object in the second channel model; if d FF with d FFThe ratio of is less than the third distance threshold, the target channel model is determined to be the first channel model; if d FF with d FF is greater than a fourth distance threshold, determining that the target channel model is the second channel model; wherein the third distance threshold is less than or equal to the fourth distance threshold.

[0448] Optionally, the processing unit 1210 is specifically configured to: determine the TA of the first signal; determine d according to the TA of the first signal; TA .

[0449] Optionally, before determining the TA of the first signal, the transceiver unit 1220 is further used to: receive first indication information, where the first indication information is used to indicate the TA of the first signal; and the processing unit 1210 is specifically used to: determine the TA of the first signal according to the first indication information.

[0450] Optionally, before determining the first spatial basis, the processing unit 1210 is further configured to: determine the trace of the spatial correlation matrix of the antenna array cur According to tra cur Determine a target channel model, where the target channel model is a first channel model or a second channel model, wherein, in the first channel model, distances from each vibrator in the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; determine a first spatial basis, including: when the target channel model is the first channel model, determine the first spatial basis.

[0451] Optionally, the processing unit 1210 is specifically configured to: determine tra ref ,tra ref is the trace of the spatial correlation matrix corresponding to the second channel model; if tra cur With tra ref The absolute value of the difference between the two is greater than the first trace threshold, and the target channel model is determined to be the first channel model; if tra cur With tra ref The absolute value of the difference between is less than the second trace threshold, and the target channel model is determined to be the second channel model; wherein the first trace threshold is greater than or equal to the second trace threshold.

[0452] Optionally, the processing unit 1210 is specifically configured to: determine tra ref ,tra ref is the trace of the spatial correlation matrix corresponding to the second channel model; if tra cur With tra ref The ratio of is greater than the third trace threshold, the target channel model is determined to be the first channel model; if tra cur With tra refis less than the fourth trace threshold, the target channel model is determined to be the second channel model; wherein the third trace threshold is greater than or equal to the fourth trace threshold.

[0453] Optionally, determine tra ref Previously, the transceiver unit 1220 was also used to: receive second indication information, the second indication information is used to indicate tra ref The processing unit 1210 is specifically configured to: determine the tra according to the second indication information ref .

[0454] Optionally, the transceiver unit 1220 is further used to: send third indication information, where the third indication information is used to indicate the target channel model.

[0455] Optionally, before determining the first spatial basis, the transceiver unit 1220 is also used to: receive fourth indication information, the fourth indication information is used to indicate the target channel model, the target channel model is the first channel model or the second channel model, wherein, in the first channel model, the distances from each vibrator of the antenna array to the first object are not equal, and in the second channel model, the distances from each vibrator in the antenna array to the first object are equal; the processing unit 1210 is also used to: determine the target channel model according to the fourth indication information; the processing unit 1210 is specifically used to: determine the first spatial basis when the target channel model is the first channel model.

[0456] Those skilled in the art can clearly understand that when the communication device 1200 is used to implement the functions of the terminal device 110, the specific working process of the communication device 1200 and the technical effects produced by the execution steps can refer to the description in the corresponding method embodiment mentioned above. For the sake of brevity, they will not be repeated here.

[0457] The communication device 1200 may be a terminal device or a chip. The processing unit 1210 may be implemented by hardware or software. When implemented by hardware, the processing unit 1210 may be a logic circuit, an integrated circuit, or the like. When implemented by software, the processing unit 1210 may be a general-purpose processor implemented by reading software code stored in a storage unit. The storage unit may be integrated into the processing unit 1210 or located independently of the processing unit 1210.

[0458] When the communication device 1200 is used to implement the function of the network device 120, the transceiver unit 1220 is used to: receive PMI, the PMI includes an identifier and a combination coefficient of the first spatial basis; the processing unit 1210 is used to: determine the first spatial basis from a spatial basis set according to the identifier of the first spatial basis, the spatial basis set includes multiple spatial basis, each of the multiple spatial basis is determined by the angle and distance of a multipath between the antenna array of the network device and the first object; determine the precoding matrix according to the first spatial basis and the combination coefficient.

[0459] Optionally, before determining the first spatial basis from the set of spatial basis according to the identifier of the first spatial basis, the processing unit 1210 is further configured to: determine the maximum value r of the distance between the terminal device and the antenna array. max and the minimum value r min , and the quantized number of bits Δd of the distance between the terminal device and the antenna array; according to r max 、r min and Δd to determine a distance candidate value set; determine an angle candidate value set; and determine a spatial basis set based on the distance candidate value set and the angle candidate value set.

[0460] Optionally, the processing unit 1210 is specifically configured to: max 、r min and Δd determine the distance interval d gap According to r max 、r min and d gap Determine the distance candidate value set, the maximum distance candidate value of the distance candidate value set is r max , the minimum distance candidate value of the distance candidate value set is r min , the difference between any two distance candidate values ​​in the distance candidate value set is d gap An integer multiple of .

[0461] Optionally, before determining the first spatial basis from the set of spatial basis according to the identifier of the first spatial basis, the processing unit 1210 is further configured to: determine the maximum value r of the distance between the terminal device and the antenna array. max and the minimum value r min , and the distance interval d gap According to r max 、r min and d gap Determine the distance candidate value set, the maximum distance candidate value of the distance candidate value set is r max , the minimum distance candidate value of the distance candidate value set is r min , the difference between two adjacent distance candidate values ​​in the distance candidate value set is d gap , d gapThere is a correlation relationship between the distance between the terminal device and the antenna array; determining a set of angle candidate values; and determining a spatial basis set based on the distance candidate value set and the angle candidate value set.

[0462] Optionally, the first spatial basis includes: an angle basis of the first subarray, and a distance basis of the first subarray; the processing unit 1210 is specifically used to: determine the angle basis of the second subarray and the distance basis of the second subarray based on the angle basis of the first subarray, the distance basis of the first subarray, and the spacing between the first subarray and the second subarray; and determine the precoding matrix based on the angle basis of the first subarray, the distance basis of the first subarray, the angle basis of the second subarray, the distance basis of the second subarray, and the combination coefficient.

[0463] Optionally, before determining the first spatial basis from the set of spatial basis according to the identifier of the first spatial basis, the processing unit 1210 is further configured to: determine the distance d between the terminal device and the antenna array TA According to d TA Determine a target channel model, where the target channel model is a first channel model or a second channel model, wherein, in the first channel model, distances from each vibrator of the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; determine the first spatial basis from the spatial basis set according to the identifier of the first spatial basis, including: when the target channel model is the first channel model, determine the first spatial basis from the spatial basis set according to the identifier of the first spatial basis.

[0464] Optionally, the processing unit 1210 is specifically configured to: determine d FF , d FF is the distance from each vibrator in the antenna array to the first object in the second channel model; if d TA with d FF The absolute value of the difference between the two is less than the first distance threshold, and the target channel model is determined to be the first channel model; if d TA with d FF The absolute value of the difference between is greater than a second distance threshold, and the target channel model is determined to be the second channel model; wherein the first distance threshold is less than or equal to the second distance threshold.

[0465] Optionally, the processing unit 1210 is specifically configured to: determine d FF , d FF is the distance from each vibrator in the antenna array to the first object in the second channel model; if d TA with d FF The ratio of is less than the third distance threshold, the target channel model is determined to be the first channel model; if d TA with d FFis greater than a fourth distance threshold, determining that the target channel model is the second channel model; wherein the third distance threshold is less than or equal to the fourth distance threshold.

[0466] Optionally, the processing unit 1210 is specifically configured to: determine the TA of the first signal; determine d according to the TA of the first signal; TA .

[0467] Optionally, before determining the first spatial basis from the set of spatial basis according to the identifier of the first spatial basis, the processing unit 1210 is further configured to: determine the trace of the spatial correlation matrix of the antenna array. cur According to tra cur Determine a target channel model, where the target channel model is a first channel model or a second channel model, wherein, in the first channel model, distances from each vibrator of the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; determine the first spatial basis from the spatial basis set according to the identifier of the first spatial basis, including: when the target channel model is the first channel model, determine the first spatial basis from the spatial basis set according to the identifier of the first spatial basis.

[0468] Optionally, the processing unit 1210 is specifically configured to: determine tra ref ,tra ref is the trace of the spatial correlation matrix corresponding to the second channel model; if tra cur With tra ref The absolute value of the difference between the two is greater than the first trace threshold, and the target channel model is determined to be the first channel model; if tra cur With tra ref The absolute value of the difference between is less than the second trace threshold, and the target channel model is determined to be the second channel model; wherein the first trace threshold is greater than or equal to the second trace threshold.

[0469] Optionally, the processing unit 1210 is specifically configured to: determine tra ref ,tra ref is the trace of the spatial correlation matrix corresponding to the second channel model; if tra cur With tra ref The ratio of is greater than the third trace threshold, the target channel model is determined to be the first channel model; if tra cur With tra ref is less than the fourth trace threshold, the target channel model is determined to be the second channel model; wherein the third trace threshold is greater than or equal to the fourth trace threshold.

[0470] Optionally, the transceiver unit 1220 is further used to: send fourth indication information, where the fourth indication information is used to indicate the target channel model.

[0471] Optionally, before determining the first spatial basis from the spatial basis set according to the identifier of the first spatial basis, the transceiver unit 1220 is also used to: receive third indication information, the third indication information is used to indicate the target channel model, the target channel model is the first channel model or the second channel model, wherein, in the first channel model, the distances from each vibrator of the antenna array to the first object are not equal, and in the second channel model, the distances from each vibrator in the antenna array to the first object are equal; the processing unit 1210 is also used to: determine the target channel model according to the third indication information; the processing unit 1210 is specifically used to: when the target channel model is the first channel model, determine the first spatial basis from the spatial basis set according to the identifier of the first spatial basis.

[0472] Optionally, before receiving the third indication information, the transceiver unit 1220 is further used to: send first indication information, where the first indication information is used to indicate TA, and TA is used to determine the target channel model.

[0473] Optionally, before receiving the third indication information, the transceiver unit 1220 is further configured to: send second indication information, where the second indication information is used to indicate the trace of the spatial correlation matrix corresponding to the second channel model. ref ,tra ref is the average value of the trace of the spatial correlation matrix of multiple terminal devices applying the second channel model, tra ref Used to determine the target channel model.

[0474] Those skilled in the art can clearly understand that when the communication device 1200 is used to implement the functions of the network device 120, the specific working process of the communication device 1200 and the technical effects produced by the execution steps can refer to the description in the corresponding method embodiment mentioned above. For the sake of brevity, they will not be repeated here.

[0475] The communication device 1200 may be a network device or a chip. The processing unit 1210 may be implemented in hardware or software. When implemented in hardware, the processing unit 1210 may be a logic circuit, an integrated circuit, or the like. When implemented in software, the processing unit 1210 may be a general-purpose processor that reads software code stored in a storage unit. The storage unit may be integrated into the processing unit 1210 or located independently of the processing unit 1210.

[0476] As shown in Figure 13, communication device 1300 includes a processor 1310 and an interface circuit 1320. Processor 1310 and interface circuit 1320 are coupled to each other. It is understood that interface circuit 1320 can be a transceiver or an input / output interface. Optionally, communication device 1300 may also include a memory 1330 for storing instructions executed by processor 1310, input data required by processor 1310 to execute instructions, or data generated by processor 1310 after executing instructions.

[0477] When the communication device 1300 is used to implement the method shown in FIG. 5 , the processor 1310 is used to implement the functions of the processing unit 1210 , and the interface circuit 1320 is used to implement the functions of the transceiver unit 1220 .

[0478] When the communication device 1300 is a terminal chip (i.e., a chip used in a terminal device), the terminal chip implements the functions of the terminal device 110 in the above-described method embodiment. When the terminal chip receives information from the base station, it can be understood that the information is first received by other modules in the terminal (such as a radio frequency module or antenna) and then sent to the terminal chip by these modules. When the terminal chip sends information to the base station, it can be understood that the information is first sent to other modules in the terminal (such as a radio frequency module or antenna) and then sent to the base station by these modules.

[0479] When the communication device 1300 is a base station chip (i.e., a chip used in a base station), the base station chip implements the functions of the network device 120 in the above-mentioned method embodiment. When the base station chip receives information from the terminal, it can be understood that the information is first received by other modules in the base station (such as a radio frequency module or antenna) and then sent to the base station chip by these modules. When the base station chip sends information to the terminal, it can be understood that the information is sent to other modules in the base station (such as a radio frequency module or antenna) and then sent to the terminal by these modules.

[0480] In this application, when entity A sends information to entity B, it can be done directly from A to B or indirectly through another entity. Similarly, when entity B receives information from entity A, it can be done directly from entity B or indirectly through another entity. Entities A and B herein can be RAN nodes or terminals, or modules within a RAN node or terminal. The sending and receiving of information can be information exchange between a RAN node and a terminal, for example, between a base station and a terminal; the sending and receiving of information can also be information exchange between two RAN nodes, for example, between a CU and a DU; the sending and receiving of information can also be information exchange between different modules within a device, for example, between a terminal chip and other modules in the terminal, or between a base station chip and other modules within the base station.

[0481] Figure 14 is a schematic diagram of the structure of a terminal device provided in an embodiment of the present application. For ease of explanation, Figure 14 only shows the main components of terminal device 1400. Terminal device 1400 can be used in the system shown in Figure 1 to implement the functions of the terminal device in the above-mentioned method embodiment. As shown in the device figure, terminal device 1400 includes a processor, memory, control circuitry, an antenna, and input / output devices. The processor is primarily used to process communication protocols and communication data, as well as control the entire terminal device, execute software programs, and process software program data, for example, to support the terminal device in performing the actions described in the above-mentioned method embodiment. The memory is primarily used to store software programs and data. The control circuit is primarily used to convert digital signals into radio frequency signals and process radio frequency signals. The control circuitry and antenna together can also be called a transceiver, which is primarily used to transmit and receive radio frequency signals in the form of electromagnetic waves. The input / output devices, such as a touch screen, display screen, and keyboard, are primarily used to receive data input by the user and output data to the user.

[0482] When a terminal device is powered on, the processor reads the software program in memory, interprets and executes its instructions, and processes the data. When data needs to be sent wirelessly, the processor processes the data and outputs a digital signal to the RF circuit. The RF circuit then processes the digital signal and transmits it as electromagnetic waves via the antenna. When data is sent to the terminal device, the RF circuit receives the RF signal via the antenna, converts it into a digital signal, and outputs the digital signal to the processor, which converts the digital signal into data and processes it.

[0483] Those skilled in the art will appreciate that, for ease of explanation, FIG14 illustrates only one memory and one processor. In an actual terminal device, multiple processors and multiple memories may exist. A memory may also be referred to as a storage medium or storage device, etc., which is not limited in this application.

[0484] As an optional implementation, the processor may include a baseband processor and / or a central processing unit (CPU). The baseband processor is primarily responsible for processing communication protocols and communication data, while the CPU is primarily responsible for controlling the entire terminal device, executing software programs, and processing data from software programs. The processor in Figure 14 may integrate the functions of both a baseband processor and a CPU. Those skilled in the art will appreciate that the baseband processor and the CPU may also be independent processors interconnected via a bus or other technology. Those skilled in the art will appreciate that a terminal device may include multiple baseband processors to accommodate different network standards, multiple CPUs to enhance its processing capabilities, and that the various components of the terminal device may be connected via various buses. The baseband processor may also be referred to as a baseband processing circuit or a baseband processing chip. The CPU may also be referred to as a central processing circuit or a central processing chip. The functionality for processing communication protocols and communication data may be built into the processor or stored in memory as a software program, with the processor executing the software program to implement the baseband processing functionality.

[0485] In the embodiments of the present application, the antenna and control circuit with transceiver functions can be regarded as the transceiver unit 1401 of the terminal device 1400, for example, used to support the terminal device to implement the receiving function and the transmitting function described in the method embodiment. The processor with processing function can be regarded as the processor 1402 of the terminal device 1400. The terminal device 1400 includes a transceiver unit 1401 and a processor 1402. The transceiver unit 1401 can also be referred to as a transceiver, a transceiver, a transceiver device, etc. For example, the device used to implement the receiving function in the transceiver unit 1401 can be regarded as a receiving unit, and the device used to implement the transmitting function in the transceiver unit 1401 can be regarded as a transmitting unit, that is, the transceiver unit 1401 includes a receiving unit and a transmitting unit. The receiving unit can also be referred to as a receiver, an input port, a receiving circuit, etc., and the transmitting unit can be referred to as a transmitter, a transmitter, or a transmitting circuit, etc. For example, the transceiver unit 1401 can include no antenna and only include the circuit portion, so that the antenna is external to the transceiver unit.

[0486] Processor 1402 can be used to execute instructions stored in the memory to control transceiver unit 1401 to receive and / or transmit signals, thereby completing the functions of the terminal device in the above-mentioned method embodiment. As an implementation method, the functions of transceiver unit 1401 can be implemented by a transceiver circuit or a dedicated transceiver chip. When performing the transmission and reception of various types of signals, processor 1402 controls transceiver unit 1401 to implement the reception. Therefore, processor 1402 is the signal transmission and reception decision maker and initiates data transmission and reception operations, while transceiver unit 1401 is the executor of signal transmission and reception.

[0487] Figure 15 is a structural diagram of a network device provided in an embodiment of the present application. For ease of explanation, Figure 15 only shows the main components of the network device 1500. The network device 1500 can be applied to the system shown in Figure 1 to implement the functions of the network device in the above method embodiment. As shown in Figure 15, the network device 1500 may include one or more DUs 1510 and one or more CUs 1520. The DU 1510 may include at least one antenna 1511, at least one radio frequency unit 1512, at least one processor 1513, and at least one memory 1514. The CU 1520 may communicate with the core network, and the CU 1520 may include at least one processor 1522 and at least one memory 1521.

[0488] The DU 1510 is primarily responsible for transmitting and receiving RF signals, converting RF signals into baseband signals, and performing some baseband processing functions. The CU 1520 includes at least one processor 1522 and at least one memory 1521. The CU 1520 and DU 1510 can communicate via interfaces. The control plane (CP) interface can be an Fs-C interface, such as F1-C, and the user plane (UP) interface can be an Fs-U interface, such as F1-U.

[0489] CU 1520 is the control center of network device 1500, also known as a processing unit. It primarily performs baseband processing functions such as channel coding, multiplexing, modulation, and spread spectrum. For example, CU 1520 can be used to control network device 1500 to execute the network device operation procedures described in the aforementioned method embodiments. DU 1510 and CU 1520 can be physically co-located or physically separated, i.e., a distributed base station.

[0490] The baseband processing functions on the DU 1510 and CU 1520 can be divided according to the protocol layers of the wireless network. For example, the functions of the PDCP layer and above are set in the CU 1520, and the functions of the protocol layers below the PDCP are set in the DU 1510.

[0491] In an optional embodiment, DU1510 can be composed of one or more single boards. Multiple single boards can jointly support a radio access network with a single access indication (such as a new radio (NR) network), or can separately support radio access networks with different access standards (such as a long-term evolution (LTE) network and an NR network). The memory 1514 is used to store necessary instructions and data, and the processor 1513 is used to control the network device 1500 to perform necessary actions. The memory 1514 and the processor 1513 can serve one or more single boards. In other words, a memory and a processor can be set separately on each single board. It is also possible to set a shared memory and processor for multiple single boards. In addition, necessary circuits can also be set on each single board.

[0492] In an optional embodiment, CU1520 can be composed of one or more single boards, and multiple single boards can jointly support a wireless access network with a single access indication (such as an NR network), or can respectively support wireless access networks with different access standards (such as an LTE network and an NR network). The memory 1521 is used to store necessary instructions and data, and the processor 1522 is used to control the network device 1500 to perform necessary actions, such as controlling the network device 1500 to execute the operation process of the network device in the above method embodiment. The memory 1521 and the processor 1522 can serve one or more single boards. That is, a memory and a processor can be set separately on each single board. It is also possible to set a shared memory and processor for multiple single boards. In addition, necessary circuits can also be set on each single board.

[0493] It should be understood that the network device 1500 shown in FIG15 is capable of implementing each process related to the network device in the method embodiments. The operations and / or functions of each module in the network device 1500 are respectively for implementing the corresponding processes in the above method embodiments. For details, please refer to the description of the above method embodiments and will not be repeated here.

[0494] It should be understood that the network device 1500 shown in FIG15 is only one possible architecture of a network device and does not constitute any limitation to this application. The method provided in this application is applicable to network devices with other architectures. For example, a network device including a CU, DU, and AAU, or a network device including a BBU and RRU. This application does not limit the specific architecture of the network device.

[0495] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0496] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC. In addition, the ASIC can be located in a base station or a terminal. The processor and storage medium can also exist in a base station or a terminal as discrete components.

[0497] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0498] 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.

[0499] 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.

[0500] 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.

[0501] It should also be understood that in this application, "when", "if" and "if" all mean that the UE or base station will take corresponding measures under certain objective circumstances. It does not limit the time, and does not require the UE or base station to take judgment actions when implementing it, nor does it mean that there are other limitations.

Claims

1. A communication method, characterized in that: include: Determine a first spatial basis, where the first spatial basis belongs to a spatial basis set, where the spatial basis set includes multiple spatial basis, and each of the multiple spatial basis is determined by an angle and a distance of a multipath between an antenna array of a network device and a first object; Determine a combination coefficient according to the first spatial domain basis; A precoding matrix indication PMI is sent, where the PMI includes an identifier of the first spatial basis and the combination coefficient.

2. The method according to claim 1, characterized in that: Before determining the first spatial basis, the method further includes: Determine the maximum value r of the distance between the terminal device and the antenna array max and the minimum value r min , and the number of quantized bits Δd of the distance between the terminal device and the antenna array; According to the max 、 min and the Δd to determine a distance candidate value set; Determine a set of candidate angle values; The spatial basis set is determined according to the distance candidate value set and the angle candidate value set.

3. The method according to claim 2, characterized in that According to the r max 、 min and the Δd determine a distance candidate value set, including: According to the max 、 min and the Δd determines the distance interval d gap ; According to the max 、 min and the gap Determine the distance candidate value set, the maximum distance candidate value of the distance candidate value set is the r max , the minimum distance candidate value of the distance candidate value set is the r min The difference between any two distance candidate values ​​in the distance candidate value set is the d gap An integer multiple of .

4. The method according to claim 3, characterized in that:

5. The method according to claim 2, characterized in that: Before determining the first spatial basis, the method further includes: Determine the maximum value r of the distance between the terminal device and the antenna array max and the minimum value r min , and the distance interval d gap ; According to the max 、 min and the gap Determine a distance candidate value set, the maximum distance candidate value of the distance candidate value set is the r max , the minimum distance candidate value of the distance candidate value set is the r min The difference between two adjacent distance candidate values ​​in the distance candidate value set is d gap , the d gap There is an associated relationship with the distance between the terminal device and the antenna array; Determine a set of candidate angle values; The spatial basis set is determined according to the distance candidate value set and the angle candidate value set.

6. The method according to any one of claims 2 to 5, characterized in that The r max and the r min It is determined based on the timing advance TA of the signal between the antenna array and the terminal device.

7. The method according to any one of claims 1 to 6, characterized in that The identification of the first airspace basis includes: an identifier of an angle basis corresponding to the first spatial domain basis, and an identifier of a distance basis corresponding to the first spatial domain basis; The PMI also includes: A bitmap of non-zero coefficients, wherein the number of bits of the bitmap is 2*L*D*M, wherein L is the number of angle bases corresponding to the multiple spatial bases, D is the number of distance bases corresponding to the multiple spatial bases, and M is the number of frequency domain bases; An oversampling rate of a distance basis corresponding to the first spatial domain basis.

8. The method according to any one of claims 1 to 7, characterized in that Before determining the first spatial basis, the method further includes: Determine the distance d between the terminal device and the antenna array TA ; According to the TA Determining a target channel model, where the target channel model is a first channel model or a second channel model, wherein in the first channel model, distances from each vibrator of the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; The determining of the first spatial basis comprises: When the target channel model is the first channel model, the first spatial basis is determined.

9. The method according to claim 8, characterized in that According to the d TA Determine the target channel model, including: Determine FF , the d FF is the distance from each vibrator in the antenna array in the second channel model to the first object; If the TA With the d FF The absolute value of the difference between the target channel model and the target channel model is less than a first distance threshold, determining that the target channel model is the first channel model; If the TA With the d FF The absolute value of the difference between is greater than a second distance threshold, determining that the target channel model is the second channel model; The first distance threshold is less than or equal to the second distance threshold.

10. The method according to claim 8, characterized in that According to the d TA Determine the target channel model, including: Determine FF , the d FF is the distance from each vibrator in the antenna array in the second channel model to the first object; If the TA With the d FF is less than a third distance threshold, determining that the target channel model is the first channel model; If the TA With the d FF is greater than a fourth distance threshold, determining that the target channel model is the second channel model; The third distance threshold is less than or equal to the fourth distance threshold.

11. The method according to any one of claims 8 to 10, characterized in that The method further comprises: Send third indication information, where the third indication information is used to indicate the target channel model.

12. The method according to any one of claims 1 to 7, characterized in that Before determining the first spatial basis, the method further includes: receiving fourth indication information, where the fourth indication information is used to indicate a target channel model, where the target channel model is a first channel model or a second channel model, wherein in the first channel model, distances from each vibrator of the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; Determine the target channel model according to fourth indication information; The determining of the first spatial basis comprises: When the target channel model is the first channel model, the first spatial basis is determined.

13. A communication method, characterized in that: include: Receiving a precoding matrix indication PMI, wherein the PMI includes an identifier and a combination coefficient of a first spatial basis; Determine the first spatial basis from a spatial basis set according to the identifier of the first spatial basis, where the spatial basis set includes multiple spatial basis, and each of the multiple spatial basis is determined by an angle and a distance of a multipath between an antenna array of a network device and a first object; A precoding matrix is ​​determined according to the first spatial basis and the combining coefficients.

14. The method according to claim 13, characterized in that Before determining the first spatial basis from a set of spatial basis according to the identifier of the first spatial basis, the method further includes: Determine the maximum value r of the distance between the terminal device and the antenna array max and the minimum value r min , and the number of quantized bits Δd of the distance between the terminal device and the antenna array; According to the max 、 min and the Δd to determine a distance candidate value set; Determine a set of candidate angle values; The spatial basis set is determined according to the distance candidate value set and the angle candidate value set.

15. The method according to claim 14, characterized in that According to the r max 、 min and the Δd determine a distance candidate value set, including: According to the max 、 min and the Δd determines the distance interval d gap ; According to the max 、 min and the gap Determine the distance candidate value set, the maximum distance candidate value of the distance candidate value set is the r max , the minimum distance candidate value of the distance candidate value set is the r min The difference between any two distance candidate values ​​in the distance candidate value set is the d gap An integer multiple of .

16. The method according to claim 15, characterized in that 17. The method according to claim 14, characterized in that Before determining the first spatial basis from a set of spatial basis according to the identifier of the first spatial basis, the method further includes: Determine the maximum value r of the distance between the terminal device and the antenna array max and the minimum value r min , and the distance interval d gap ; According to the max 、 min and the gap Determine a distance candidate value set, the maximum distance candidate value of the distance candidate value set is the r max , the minimum distance candidate value of the distance candidate value set is the r min The difference between two adjacent distance candidate values ​​in the distance candidate value set is d gap , the d gap There is an associated relationship with the distance between the terminal device and the antenna array; Determine a set of candidate angle values; The spatial basis set is determined according to the distance candidate value set and the angle candidate value set.

18. The method according to any one of claims 14 to 17, characterized in that The r max and the r min It is determined based on the timing advance TA of the signal between the antenna array and the terminal device.

19. The method according to any one of claims 13 to 18, characterized in that The identification of the first airspace basis includes: an identifier of an angle basis corresponding to the first spatial domain basis, and an identifier of a distance basis corresponding to the first spatial domain basis; The PMI also includes: A bitmap of non-zero coefficients, wherein the number of bits of the bitmap is 2*L*D*M, wherein L is the number of angle bases corresponding to the multiple spatial bases, D is the number of distance bases corresponding to the multiple spatial bases, and M is the number of frequency domain bases; An oversampling rate of a distance basis corresponding to the first spatial domain basis.

20. The method according to any one of claims 13 to 19, characterized in that Before determining the first spatial basis from a set of spatial basis according to the identifier of the first spatial basis, the method further includes: Determine the distance d between the terminal device and the antenna array TA ; According to the TA Determining a target channel model, where the target channel model is a first channel model or a second channel model, wherein in the first channel model, distances from each vibrator of the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; The determining the first spatial basis from a set of spatial basis according to the identifier of the first spatial basis includes: When the target channel model is the first channel model, the first spatial basis is determined from the spatial basis set according to an identifier of the first spatial basis.

21. The method according to claim 20, characterized in that According to the d TA Determine the target channel model, including: Determine FF , the d FF is the distance from each vibrator in the antenna array in the second channel model to the first object; If the TA With the d FF The absolute value of the difference between the target channel model and the target channel model is less than a first distance threshold, determining that the target channel model is the first channel model; If the TA With the d FF The absolute value of the difference between is greater than a second distance threshold, determining that the target channel model is the second channel model; The first distance threshold is less than or equal to the second distance threshold.

22. The method according to claim 20, characterized in that According to the d TA Determine the target channel model, including: Determine FF , the d FF is the distance from each vibrator in the antenna array in the second channel model to the first object; If the TA With the d FF is less than a third distance threshold, determining that the target channel model is the first channel model; If the TA With the d FF is greater than a fourth distance threshold, determining that the target channel model is the second channel model; The third distance threshold is less than or equal to the fourth distance threshold.

23. The method according to any one of claims 20 to 22, characterized in that The method further comprises: Send fourth indication information, where the fourth indication information is used to indicate the target channel model.

24. The method according to any one of claims 13 to 19, characterized in that Before determining the first spatial basis from a set of spatial basis according to the identifier of the first spatial basis, the method further includes: receiving third indication information, where the third indication information is used to indicate a target channel model, where the target channel model is a first channel model or a second channel model, wherein in the first channel model, distances from each vibrator of the antenna array to the first object are not equal, and in the second channel model, distances from each vibrator in the antenna array to the first object are equal; Determine the target channel model according to the third indication information; The determining the first spatial basis from a set of spatial basis according to the identifier of the first spatial basis includes: When the target channel model is the first channel model, the first spatial basis is determined from the spatial basis set according to an identifier of the first spatial basis.

25. A communication device, characterized in that: include: A processor and an interface circuit, wherein the interface circuit is used to receive signals from other communication devices and transmit them to the processor or to send signals from the processor to other communication devices, wherein the processor is used to implement the method as described in any one of claims 1 to 12 through a logic circuit or by executing code instructions, or the processor is used to implement the method as described in any one of claims 13 to 24 through a logic circuit or by executing code instructions.

26. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program or instructions, and when the computer program or instructions are executed by the communication device, the method according to any one of claims 1 to 12 is implemented, or the method according to any one of claims 13 to 24 is implemented.

Images