RU2846435C2 - Method and device for providing channel state information (csi), method and device for determining a precoding matrix and a communication device - Google Patents

Abstract

FIELD: communication technique.

SUBSTANCE: present invention relates to mobile communication. Method includes: determining CSI information corresponding to each of T consecutive time instances, based on actual downlink information at each of T consecutive time instances; and providing CSI information to a network device, wherein the CSI includes indication information on frequency domain basis vectors, wherein the indication information on frequency domain basis vectors is used to indicate M frequency domain basis vectors selected by the terminal; wherein the beam used for the downlink pilot signals with beamforming is determined based on the uplink channel information estimated from the uplink reference signal, wherein the CSI information is used by the network device when determining the precoding matrix for the downlink data transmission at the time t, wherein the time t comes after T consecutive time instances.

EFFECT: reduced amount of service data transmitted by a terminal device over an uplink channel.

17 cl, 11 dwg

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[0001] The present invention relates to the field of mobile communication, in particular to a method for providing channel status information (CSI, Channel Status Information), a device for providing CSI information, a method for determining a precoding matrix, a device for determining a precoding matrix, and a device.

LEVEL OF TECHNOLOGY

[0002] In a New Radio (NR) system, a terminal provides channel state information (CSI) to a network device so that the network device can calculate a precoding matrix, which is used for downlink data transmission, based on the information provided by the terminal.

[0003] Release 16 (R16) provides the R16 Type II (Type II) codebook and the R16 Type II port selection codebook. R17 provides the R17 Type II port selection codebook. With these codebooks, the terminal can provide quantized CSI information with high accuracy.

[0004] If the terminal moves at a low speed, the network device can accurately calculate a precoding matrix for the corresponding channel based on the above codebook provided by the terminal, and thereby improve the data transmission efficiency. If the terminal moves at a medium or high speed, when using the same CSI information provision cycle as in the case of moving at a low speed, the precoding matrix calculated based on the above codebook may not correspond to the channel state, since the movement of the terminal may cause rapid changes in the channel at different times, resulting in a decrease in data transmission efficiency. Therefore, an urgent problem to be solved is to determine an appropriate codebook and calculate a precoding matrix corresponding to a channel in which rapid changes occur.

ESSENCE OF THE INVENTION

[0005] In the embodiments of the present invention, a method for providing channel state information CSI, a device for providing CSI information, a method for determining a precoding matrix, a device for determining a precoding matrix, and a device are provided. The following technical solutions are used for this.

[0006] According to one aspect of the present invention, a method for providing CSI information is provided. The method is implemented by a terminal. The method includes:

[0007] transmitting an uplink reference signal to a network device;

[0008] receiving downlink pilot signals with beamforming transmitted by the network device at each of T consecutive times;

[0009] estimating actual downlink channel information at each of T consecutive times based on downlink beamforming pilot signals received at each of T consecutive times;

[0010] determining CSI information corresponding to each of the T consecutive times based on actual downlink channel information at each of the T consecutive times; and

[0011] providing CSI information to a network device;

[0012] wherein a beam used for downlink beamforming pilot signals is determined based on uplink channel information estimated from an uplink reference signal, wherein the CSI information is used by the network device in determining a precoding matrix for downlink data transmission at time t, wherein time t occurs after T consecutive times, and T is a positive integer.

[0013] According to another aspect of the present invention, a method for determining a pre-coding matrix is provided. The method is implemented by a network device and includes:

[0014] receiving an uplink reference signal transmitted by the terminal;

[0015] estimating uplink information based on an uplink reference signal and determining a beam for transmitting downlink pilot signals depending on the uplink information;

[0016] transmitting downlink pilot signals to the terminal with beamforming at each of T consecutive times;

[0017] receiving CSI information provided by the terminal corresponding to each of T consecutive moments in time; and

[0018] determining a precoding matrix for transmitting data on a downlink channel at time t taking into account the CSI information;

[0019] wherein the CSI information is determined by the terminal based on downlink pilot signals with beamforming, and the time instant t occurs after T consecutive times, and T is a positive integer.

[0020] According to another aspect of the present invention, a device for providing CSI information is provided. The device includes:

[0021] a transmitting module configured to transmit an uplink reference signal to a network device;

[0022] a receiving module configured to receive downlink beamforming pilot signals transmitted by the network device at each of T consecutive times; and

[0023] a determining module configured to estimate actual downlink channel information at each of T consecutive times based on downlink beamforming pilot signals received at each of T consecutive times;

[0024] wherein the determining module is further configured to determine the CSI information corresponding to each of the T consecutive times based on the actual downlink channel information at each of the T consecutive times; and

[0025] the transmitting module is further configured to provide CSI information to the network device;

[0026] wherein a beam used for downlink beamforming pilot signals is determined based on uplink channel information estimated from an uplink reference signal, wherein the CSI information is used by the network device in determining a precoding matrix for downlink data transmission at time t, wherein time t occurs after T consecutive times, and T is a positive integer.

[0027] According to another aspect of the present invention, there is provided an apparatus for determining a precoding matrix, which includes:

[0028] a receiving module configured to receive an uplink reference signal transmitted by the terminal;

[0029] a determining module configured to estimate uplink information based on an uplink reference signal and determine a beam for transmitting downlink pilot signals depending on the uplink information; and

[0030] a transmitting module configured to transmit downlink pilot signals to the terminal in a beam-forming manner at each of T consecutive times;

[0031] wherein the receiving module is further configured to receive the CSI information provided by the terminal corresponding to each of the T consecutive moments in time; and

[0032] the determining module is further configured to determine a precoding matrix for transmitting data on a downlink channel at time t taking into account the CSI information;

[0033] wherein the CSI information is determined by the terminal based on downlink pilot signals with beamforming, and the time instant t occurs after T consecutive times, and T is a positive integer.

[004] According to another aspect of the present invention, a terminal is proposed. The terminal includes: a processor; a transceiver connected to the processor; and a memory for storing instructions executable by the processor. The processor is configured to load and execute executable instructions for implementing the method for providing CSI information according to the above-described aspect.

[0035] According to another aspect of the present invention, a network device is proposed. The network device includes: a processor; a transceiver connected to the processor; a memory for storing instructions executable by the processor. The processor is configured to load and execute executable instructions for implementing the method for determining a precoding matrix according to the above-described aspect.

[0036] According to another aspect of the present invention, a computer-readable storage medium is provided, on which executable instructions are stored, wherein the executable instructions are loaded and executed by a processor to implement a method for providing CSI information or a method for determining a precoding matrix according to the aspects described above.

[0037] According to another aspect of the present invention, a microcircuit is proposed. The microcircuit includes a programmable logic circuit and/or program instructions. When the microcircuit operates on a computer device, a method for providing CSI information or a method for determining a precoding matrix according to the aspects described above is implemented.

[0038] According to another aspect of the present invention, a computer program product or a computer program is provided. The computer program product or the computer program includes computer instructions. The computer instructions are stored on a computer-readable storage medium. A processor reads the computer instructions from the computer-readable storage medium and executes the computer instructions in such a way that the computer device implements a method for providing CSI information or a method for determining a precoding matrix according to the aspects described above.

[0039] The technical solution proposed in the present invention provides at least the following useful results:

[0040] The terminal determines CSI information from downlink beamforming pilot signals at each of T consecutive times, and the correlation of channel information in the time domain may be taken into account in the process of determining the CSI information. The network device uses the CSI information to determine a precoding matrix, which allows the network device to calculate precoding matrices at different future times based on the CSI information provided by the terminal device once. In addition to ensuring data transmission efficiency, this makes it possible to prevent the terminal from frequently providing CSI information due to its rapid movement, to shorten the period of providing CSI information by the terminal, and to reduce the amount of overhead data transmitted by the terminal in the uplink. Moreover, by using the downlink beamforming pilot signals, it is possible to improve the accuracy of determining the CSI information.

BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly explain the technical solutions proposed in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly presented below. It is obvious that the drawings described below relate only to individual embodiments of the present invention. Based on these drawings, those skilled in the art can create other drawings without further research.

[0042] Fig. 1 is a block diagram of the architecture of a communication system proposed in one embodiment of the present invention.

[0043] Fig. 2 is a flow chart of a method for providing channel state information (CSI) proposed in one embodiment of the present invention.

[0044] Fig. 3 is a flow chart of a method for determining a precoding matrix proposed in one embodiment of the present invention.

[0045] Fig. 4 is a flow chart of a method for determining a precoding matrix proposed in one embodiment of the present invention.

[0046] Fig. 5 shows a diagram of a method for transmitting a Channel Status Information-Reference Signal (CSI-RS) proposed in one embodiment of the present invention.

[0047] Fig. 6 is a flow chart of a method for determining a precoding matrix proposed in one embodiment of the present invention.

[0048] Fig. 7 is a diagram of a method for transmitting a CSI-RS signal proposed in one embodiment of the present invention.

[0049] Fig. 8 is a flow chart of a method for determining a precoding matrix proposed in one embodiment of the present invention.

[0050] Fig. 9 is a block diagram of a device for providing CSI information proposed in one embodiment of the present invention.

[0051] Fig. 10 is a block diagram of a device for determining a pre-coding matrix proposed in one embodiment of the present invention.

[0052] Fig. 11 shows a block diagram of a communication device proposed in one embodiment of the present invention.

DETAILED DESCRIPTION

[0053] To explain the objectives, technical solutions and advantages of the present invention, embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0054] This document provides detailed descriptions of typical embodiments of the invention, examples of which are shown in the accompanying drawings. When drawings are referred to in the following description, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The embodiments discussed below are not exhaustive of all implementations that correspond to the present invention. Rather, they are merely examples of devices and methods that correspond to aspects of the present invention according to the appended claims.

[0055] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present invention. Unless the context clearly dictates otherwise, as used in the present description and the appended claims, the singular includes the plural. It should be understood that the expression "and/or" as used herein includes and includes any or all possible combinations of one or more of the corresponding listed elements.

[0056] It should also be understood that although the terms "first," "second," "third," etc. may be used herein to describe various information, they do not impose limitations on this information. These terms are used only to distinguish between the same types of information. For example, first information may also be referred to as second information, and second information may similarly be referred to as first information without violating the scope of protection of the present invention. Depending on the context, the word "if" may be interpreted herein as "when," "as," or "as a result of determination.

[0057] In the New Radio (NR) system, the terminal provides channel state information (CSI) to the network device so that the network device can calculate a precoding matrix used for downlink data transmission based on the information provided by the terminal. In Release 16 (R16), the R16 Type II codebook and the R16 Type II port selection codebook are provided. In R17, the R17 Type II port selection codebook is provided. With these codebooks, the terminal can provide quantized CSI information with high accuracy. The network device calculates a precoding matrix used for downlink data transmission based on the above codebook provided by the terminal, which makes it possible to adapt the data transmission process to the change in the channel state and improve the data transmission efficiency.

[0058] Introduction to the R16 Type II Code Book and the R16 Type II Port Selection Code Book.

[0059] The structure of the R16 Type II codebook and the R16 Type II port selection codebook can be represented as . Expression is a frequency domain compression matrix consisting of frequency domain basis vectors (FD (Frequency Domain) basis vectors), where - the number of sub-ranges of the precoding matrix indicator (PMI), - the number of basis vectors FD, if the transmission rank is v, and - a complex number.

[0060] For the R16 Type II code book, the expression is a diagonal compression matrix in the spatial domain, consisting of spatial domain basis vectors (SD (Spatial Domain) basis vectors), where - the number of transmitting antenna ports, and - the number of SD basis vectors in one polarization direction. Typically, an antenna has two polarization directions, and the same SD basis vector is used in both polarization directions.

[0061] For the R16 Type II port selection codebook, the expression is a diagonal port selection matrix, where P is the number of channels for the channel state information reference signals (CSI-RS) and one polarization direction consists of L unit basis vectors. Typically, an antenna has two polarization directions, and the same L unit basis vectors are used in both polarization directions. - a positive integer. The terminal selects L serial ports from P ports to provide information.

[0062] Expression is a matrix of weight coefficients. For each transmission level, the number of non-zero weight coefficients does not exceed . Codebook parameters L, And are defined and configured for the terminal by the network device. This transmission layer is used by the network device to map code words to ports.

[0063] When the transmission rank v>1, the same L basis vectors SD are used at all transmission levels, and matrices are used independently at each level And , and different FD basis vectors can be used at different levels . For example, matrices , And are determined and calculated by the terminal estimating the actual channel information based on the received beamforming CSI-RS signal transmitted by the network device. The CSI-RS beam is calculated by the network device based on the uplink channel angle estimation information.

[0064] Introduction to the R17 Type II Port Selection Code Book.

[0065] The structure of the R17 Type II port selection codebook can also be represented as , Where - diagonal port selection matrix, P is the number of CSI-RS ports, one polarization direction consists of L unit basis vectors, and the same L unit basis vectors are used in both polarization directions. The difference from the R16 Type II port selection codebook is that the R17 Type II codebook is transmitted by the terminal by freely choosing L=K ₁ /2, K ₁ =αP ports from P ports.

[0066] Expression is a matrix of weight coefficients. For each transmission level, the number of non-zero weight coefficients does not exceed . Codebook parameters And are defined and configured for the terminal by the network device.

[0067] Matrix can be turned off and on. When the matrix off, matrix represented by a basis vector of length and all elements equal to 1. When the matrix included, matrix consists of two frequency domain basis vectors of length , which includes a basis vector of length and all elements equal to 1. Two frequency domain basis vectors are selected from a continuous discrete Fourier transform (DFT) window of size N, where N=2 or 4.

[0068] For example, matrices , And are determined and calculated by the terminal device estimating the actual channel information based on the received beamforming CSI-RS signal transmitted by the network device. The CSI-RS beam is calculated by the network device based on the uplink angle and delay estimation information.

[0069] When a user (terminal) moves at a medium or high speed, CSI information needs to be provided for a short period of time in order to obtain an accurate precoding matrix. If the Type II codebook is still used to provide CSI information, the amount of overhead in the uplink may increase significantly. If the CSI information provision period used by the user remains unchanged or is long, the system performance may decrease.

[0070] If the terminal moves at a medium or high speed, the Doppler shift may cause the channel to change rapidly over time. If the Type II codebook is still used, the terminal needs to frequently transmit CSI information to adapt to the changes in the channel in order to ensure data transmission efficiency, since otherwise the data transmission efficiency may be reduced. However, frequent provision of CSI information may result in an increase in the overhead of the terminal in the uplink channel. Over a certain period of time, channel data at different times is correlated in the time domain, or the Doppler shift remains fixed over a certain period of time, so that there is a correlation of channel information in the time domain. By using the method proposed in the embodiments of the present invention, correlation of channel information in the time domain or Doppler channel information can be used to solve the above problem. An improved structure of the above-mentioned Type II R16 and/or R17 port selection codebook using Doppler channel information is implemented, so that a network device can calculate precoding matrices at different future times based on the CSI information provided by a terminal device once. In addition to ensuring data transmission efficiency, this makes it possible to prevent the terminal from frequently providing CSI information due to its rapid movement, shorten the period of providing CSI information by the terminal, and reduce the amount of service data, information transmitted by the terminal in the uplink channel.

[0071] Fig. 1 shows a block diagram of the architecture of a communication system proposed in one embodiment of the present invention. The communication system may include: a terminal 10, an access network device 20, and a core network device 30.

[0072] The terminal 10 may refer to a user equipment UE (User Equipment), an access terminal, a user unit, a user station, a mobile station, a mobile platform, a remote station, a remote terminal, a mobile device, a wireless communication device, a user agent, or a user device. Alternatively, the terminal may also be a mobile phone, a cordless phone, a SIP (Session Initiation Protocol) phone, a WLL (Wireless Local Loop) station or a PDA (Personal Digital Assistant), a portable device with a wireless communication function, a computing device or other processor devices connected to a wireless modem, a device installed on a vehicle, a wearable device, a terminal in a 5GS (5th Generation System) system, a terminal of future advanced PLMN (Public Land Mobile Network) networks, etc., and embodiments of the present invention are not limited to the listed devices. For simplicity of presentation, the above devices may be collectively referred to as terminals. Typically, a plurality of terminals 10 are used, and one or more terminals 10 may be located in a cell served by an access network device 20.

[0073] The access network device 20 is a device that is deployed in the access network and provides a wireless communication function for the terminal 10. The access network device 20 may be various types of macro base stations, micro base stations, relay stations, access points, etc. In systems that use various wireless access technologies, devices with the functions of access network devices may be called by different names. For example, in the 5G NR system, they are called gNodeB or gNB. As communication technologies develop, the term "access network device" may change. In the description of the embodiments of the present invention, the above-mentioned devices that provide wireless communication functions to the terminal 10 may be collectively referred to as access network devices for ease of explanation. Alternatively, the access network device 20 may be used to establish communication between the terminal 10 and the core network device 30. For example, in the LTE system, the access network device 20 may be an EUTRAN (Evolved Universal Terrestrial Radio Access Network) or one or more eNodeB stations in the EUTRAN; in the 5G NR system, the access network device 20 may be an RAN or one or more gNB stations in the RAN.

[0074] The functions of the core network device 30 include providing user connection, user management and service provision, and performing transport network functions to provide interaction with an external network. For example, the core network device in the 5G NR system may include an AMF (Access and Mobility Management Function) entity, a UPF (User Plane Function) entity, a SMF (Session Management Function) entity, a Location Management Function (LMF) entity, and other derivatives. The access network device 20 and the core network device 30 may be collectively referred to as network devices. In the embodiments of the present invention, the core network device 30 is, as an example for explanation, an LMF network element.

[0075] In one example, the access network device 20 and the core network device 30 communicate with each other via some wireless technology, such as via the NG interface in a 5G NR system. The access network station 20 and the terminal 10 may communicate with each other via some wireless technology, such as via the Uu interface.

[0076] Fig. 2 is a flow chart of a method for providing CSI information proposed in one embodiment of the present invention. This method can be implemented by the terminal shown in Fig. 1. The method includes the following sequence of actions.

[0077] In step 202, the uplink reference signal is transmitted to the network device.

[0078] Alternatively, the uplink reference signal is a Sounding Reference Signal (SRS), which may also be referred to as a channel sounding reference signal.

[0079] At step 204, downlink pilot signals with beamforming transmitted by the network device at each of T consecutive moments in time are received.

[0080] The beam used by the downlink beamforming pilot signals is determined based on the uplink channel information estimated from the uplink reference signal. The downlink pilot signal is used by the terminal to determine the actual downlink channel information. T is a positive integer. Optionally, the downlink beamforming pilot signal includes at least one of the following elements:

CSI-RS signal;

Demodulation Reference Signal (DMRS); or

a combination of CSI-RS and DMRS signals.

[0081] Alternatively, the above parameter T is determined in at least one of the following ways:

configured by the network device; or

is pre-determined by negotiation between the terminal device and the network device.

[0082] At step 206, actual downlink channel information is estimated at each of T consecutive times based on downlink beamforming pilot signals received at each of T consecutive times.

[0083] Alternatively, the terminal may estimate actual information about the downlink channel at each of T consecutive times based on downlink beamforming pilot signals received at each of T consecutive times. The actual information about the downlink channel is used to determine the characteristics of the downlink channel.

[0084] At step 208, CSI information corresponding to each of the T consecutive times is determined based on the actual downlink channel information at each of the T consecutive times.

[0085] Based on the CSI information determined by the terminal, the network device can determine a precoding matrix for transmitting data on a downlink channel. The CSI information can also be called codebook parameter information. Alternatively, the CSI information includes the following two situations.

[0086] First situation

[0087] The CSI information includes at least one of the following elements:

indication of port selection;

indication information about the frequency domain basis vectors;

indication information about the Doppler component in the time domain; or

indication information about weighting factors.

[0088] The port selection indicator information is used to indicate L reference signal ports selected by the terminal, the frequency domain basis vector indicator information is used to indicate M frequency domain basis vectors selected by the terminal, the time domain Doppler component indicator information is used to indicate K time domain Doppler components selected by the terminal, and the weighting coefficient indicator information is used to indicate weighting coefficients determined by the terminal. The parameter L, the parameter M, and the parameter K are positive integers. Alternatively, the time domain Doppler component indicator information is used to indicate K time domain basis vectors selected by the terminal, or K phase shifts. That is, the time domain Doppler component is represented by a phase shift or a basis vector.

[0089] Alternatively, the above parameter K is determined in at least one of the following ways:

configured by the network device;

is predetermined by negotiation between the terminal device and the network device; or

is determined by the terminal according to the actual information about the downlink channel.

[0090] When the terminal determines the parameter K based on the actual downlink information, the terminal transmits the parameter K determined by it to the network device.

[0091] Alternatively, in the case where the parameter T and/or the parameter K are configured by the network device, the parameter T and/or the parameter K are configured by the network device for the terminal by means of at least one of the following types of signaling:

Radio Resource Control (RRC) signaling;

Medium Access Control-Control Unit (MAC-CE) signaling; or

Downlink Control Information (DCI).

[0092] Alternatively, the Doppler component in the time domain satisfies at least one of the following conditions:

in the case where the data transmission in the downlink channel is carried out at the same level, the Doppler components in the time domain corresponding to different polarization directions coincide or differ;

the Doppler components in the time domain corresponding to different ports of the reference signal are the same or different; or

Doppler components in the time domain corresponding to different time-frequency components coincide or differ.

[0093] The time-frequency component consists of a frequency domain basis vector and a Doppler component in the time domain. Since there are usually two polarization directions, the Doppler components in the time domain corresponding to the two polarization directions are the same or different. The polarization direction mentioned above refers to the polarization direction in which the network device transmits data to the terminal.

[0094] Alternatively, in the case where the downlink data transmission is performed on multiple layers, the Doppler components in the time domain corresponding to the different transmission layers are the same or different. Multilayer transmission implies the presence of multiple transmission layers that are used by the network device to map code words to ports.

[0095] Alternatively, the Doppler component in the time domain is represented by a phase shift between adjacent times for transmitting downlink pilot signals; or the Doppler component in the time domain is represented by a basis vector.

[0096] In the case where the Doppler component in the time domain is represented by a phase shift, then if the parameter K is determined by the terminal, this parameter K is determined by the terminal depending on the number of non-zero coefficients for each transmission level.

[0097] Alternatively, the Doppler component in the time domain is represented by a basis vector, wherein the basis vector includes at least one of the following vectors:

basis vector of the discrete Fourier transform (DFT);

basis vector of the discrete cosine transform (DCT);

polynomial basis vector.

[0098] Second situation

[0099] The CSI information includes at least one of the following elements:

indication of port selection;

indication information about the frequency domain basis vectors; or

indication information about weighting factors.

[00100] The port selection indication information is used to indicate L reference signal ports selected by the terminal, the frequency domain basis vector indication information is used to indicate M frequency domain basis vectors selected by the terminal, and the weight coefficient indication information is used to indicate T groups of weight coefficients corresponding to T consecutive time instants determined by the terminal. The information about the positions of the non-zero coefficients in the matrices of the T groups of weight coefficients is the same, and the parameters L and M are positive integers.

[00101] Alternatively, each of the above parameters K is determined in at least one of the following ways:

configured by the network device;

is predetermined by negotiation between the terminal device and the network device; or

determined by the terminal according to the downlink information.

[00102] Alternatively, the above-mentioned reference signal port includes at least one of the following ports:

channel state information reference signal (CSI-RS) port; or

Demodulation Reference Signal (DMRS) port.

[00103] At step 210, the CSI information is transmitted to the network device.

[00104] Alternatively, the terminal may provide the network device with all or part of the CSI information determined by the terminal. The CSI information is used by the network device to calculate a precoding matrix for transmitting data on a downlink at time t. Time t occurs after T consecutive times. Alternatively, the network device calculates a precoding matrix for transmitting data on a downlink at each of the T consecutive times based on the CSI information provided by the terminal as a precoding matrix at time t. The network device may also calculate the precoding matrix directly at time t based on the CSI information provided by the terminal.

[00105] Thus, in the method proposed in the embodiments of the present invention, the terminal determines CSI information from downlink beamforming pilot signals at each of T consecutive times, and in the process of determining the CSI information, correlation of channel information in the time domain can be taken into account. The network device uses the CSI information to determine a precoding matrix, which allows the network device to calculate precoding matrices at different future times based on the CSI information provided by the terminal device once. In addition to ensuring data transmission efficiency, this makes it possible to prevent the terminal from frequently providing CSI information due to its rapid movement, to shorten the period of providing CSI information by the terminal, and to reduce the amount of overhead data transmitted by the terminal in the uplink. Moreover, by using the downlink beamforming pilot signals, the accuracy of determining the CSI information can be improved.

[00106] Fig. 3 is a flow chart of a method for determining a pre-coding matrix proposed in one embodiment of the present invention. This method can be implemented by the network device shown in Fig. 1. The method includes the following sequence of actions.

[00107] In step 302, an uplink reference signal transmitted by the terminal is received.

[00108] Alternatively, the uplink reference signal is an SRS signal.

[00109] In step 304, uplink channel information is estimated based on the uplink reference signal and a beam for transmitting downlink pilot signals is determined depending on the uplink channel information.

[00110] The network device may estimate uplink channel information based on the uplink reference signal, thereby determining a beam. The beam determined by the network device is used to form beams when transmitting a downlink pilot signal. Optionally, the downlink pilot signal includes at least one of the following signals:

CSI-RS signal;

DMRS signal; or

a combination of CSI-RS and DMRS signals.

[00111] At step 306, downlink pilot signals are transmitted to the terminal with beamforming at each of T consecutive times.

[00112] The downlink beamforming pilot signal is used by the terminal to determine the actual information about the downlink channel. T is a positive integer. Alternatively, the above parameter T is determined by at least one of the following methods:

configured by the network device; or

is pre-determined by negotiation between the terminal device and the network device.

[00113] Alternatively, the network device transmits downlink pilot signals to the terminal with beamforming at each of T consecutive times using the same pilot resource port and the same beam. The same pilot resource port includes a port corresponding to the same pilot resources or the same port indexed by different pilot resources.

[00114] Alternatively, the network device transmits different downlink pilot signals with beamforming to the terminal at each of T consecutive times using the same pilot resource port. The same pilot resource ports include ports with the same position in the frequency domain among ports configured with different pilot resources.

[00115] At step 308, the CSI information provided by the terminal corresponding to each of the T consecutive moments in time is obtained.

[00116] The CSI information is determined by the terminal based on the downlink beamforming pilot signals. The terminal may estimate the actual downlink channel information at each of T consecutive times based on the downlink beamforming pilot signals received at each of T consecutive times. Then, the CSI information corresponding to each of the T consecutive times is determined based on the actual downlink channel information at each of the T consecutive times. Alternatively, the CSI information includes the following two situations.

[00117] First situation

[00118] The CSI information includes at least one of the following elements:

indication of port selection;

indication information about the frequency domain basis vectors;

indication information about the Doppler component in the time domain; or

indication information about weighting factors.

[00119] The port selection indication information is used to indicate L reference signal ports selectable by the terminal, the frequency domain basis vector indication information is used to indicate M frequency domain basis vectors selectable by the terminal, the time domain Doppler component indication information is used to indicate K time domain Doppler components selectable by the terminal, and the weighting coefficient indication information is used to indicate weighting coefficients determined by the terminal. The parameter L, the parameter M, and the parameter K are positive integers. Alternatively, the time domain Doppler component indication information is used to indicate K time domain basis vectors selectable by the terminal, or K phase shifts. That is, the time domain Doppler component is represented by a phase shift or a basis vector.

[00120] Alternatively, the Doppler component in the time domain satisfies at least one of the following conditions:

in the case where the data transmission in the downlink channel is carried out at the same level, the Doppler components in the time domain corresponding to different polarization directions coincide or differ;

the Doppler components in the time domain corresponding to different ports of the reference signal are the same or different; or

Doppler components in the time domain corresponding to different time-frequency components coincide or differ.

[00121] The time-frequency component consists of a frequency domain basis vector and a Doppler component in the time domain. Since there are usually two polarization directions, the Doppler components in the time domain corresponding to the two polarization directions are the same or different. The polarization direction mentioned above refers to the polarization direction in which the network device transmits data to the terminal.

[00122] Alternatively, in the case where the downlink data transmission is performed on multiple layers, the Doppler components in the time domain corresponding to the different transmission layers are the same or different. Multilayer transmission implies the presence of multiple transmission layers that are used by the network device to map code words to ports.

[00123] Alternatively, the Doppler component in the time domain is represented by a phase shift between adjacent times for transmitting downlink pilot signals; or the Doppler component in the time domain is represented by a basis vector.

[00124] In the case where the Doppler component in the time domain is represented by a phase shift, then if the parameter K is determined by the terminal, this parameter K is determined by the terminal depending on the number of non-zero coefficients for each transmission level.

[00125] Alternatively, the Doppler component in the time domain is represented by a basis vector, wherein the basis vector includes at least one of the following vectors:

DFT basis vector;

DCT basis vector;

polynomial basis vector.

[00126] Second situation

[00127] The CSI information includes at least one of the following elements:

indication of port selection;

indication information about the frequency domain basis vectors; or

indication information about weighting factors.

[00128] The port selection indication information is used to indicate L reference signal ports selected by the terminal, the frequency domain basis vector indication information is used to indicate M frequency domain basis vectors selected by the terminal, and the weight coefficient indication information is used to indicate T groups of weight coefficients corresponding to T consecutive time instants determined by the terminal. The information about the positions of the non-zero coefficients in the matrices of the T groups of weight coefficients is the same, and the parameters L and M are positive integers.

[00129] At step 310, based on the CSI information, a precoding matrix is determined for data transmission on a downlink channel at time t.

[00130] The time t occurs after T consecutive times. Alternatively, the network device calculates a precoding matrix for transmitting data on a downlink channel at each of the T consecutive times based on the CSI information provided by the terminal as a precoding matrix at the time t. The network device may also calculate the precoding matrix directly at the time t based on the CSI information provided by the terminal.

[00131] In the process of calculating the precoding matrix for transmitting data on a downlink channel at time t based on the CSI information, the network device may use the above-mentioned Doppler component in the time domain. Alternatively, for the first situation with the CSI information described above, the Doppler component in the time domain is determined by the terminal. Alternatively, for the second situation with the CSI information described above, the Doppler component in the time domain is determined by the network device.

[00132] Thus, in the method proposed in the embodiments of the present invention, the terminal determines CSI information from downlink beamforming pilot signals at each of T consecutive times, and in the process of determining the CSI information, correlation of channel information in the time domain can be taken into account. The network device uses the CSI information to determine a precoding matrix, which allows the network device to calculate precoding matrices at different future times based on the CSI information provided by the terminal device once. In addition to ensuring data transmission efficiency, this makes it possible to prevent the terminal from frequently providing CSI information due to its rapid movement, to shorten the period of providing CSI information by the terminal, and to reduce the amount of overhead data transmitted by the terminal in the uplink. Moreover, by using the downlink beamforming pilot signals, the accuracy of determining the CSI information can be improved.

[00133] Using the method proposed in the embodiments of the present invention, an improved procedure for providing CSI information can be implemented, in which a Doppler component in the time domain is used to determine a precoding matrix for transmitting data on a downlink. Using the Doppler information of the channel (the Doppler component in the time domain) makes it possible to take into account the correlation of the channel information in the time domain. Using the Doppler component in the time domain to determine the precoding matrix makes it possible for the network device to calculate precoding matrices at different future times based on the CSI information provided by the terminal once. In addition to ensuring the efficiency of data transmission, this makes it possible to prevent the terminal from frequently providing CSI information due to its rapid movement, to shorten the period of providing CSI information by the terminal, and to reduce the amount of overhead data transmitted by the terminal on the uplink. The Doppler component in the time domain can be represented by a phase shift between adjacent times for transmitting downlink pilot signals by the network device, or it can also be represented by a basis vector. In addition, the Doppler component in the time domain can be determined by a terminal or a network device. The method proposed in the present invention is considered in three embodiments.

[00134] 1. For the situation where the Doppler component in the time domain is represented by a phase shift, wherein the Doppler component in the time domain is determined by the terminal

[00135] Fig. 4 is a flow chart of a method for determining a precoding matrix proposed in one embodiment of the present invention. This method can be applied in the system shown in Fig. 1. The method includes the following sequence of actions.

[00136] In step 402, the terminal transmits an uplink reference signal to the network device.

[00137] Alternatively, the uplink reference signal is an SRS signal.

[00138] In step 404, the network device evaluates uplink channel information based on the uplink reference signal and determines a beam for transmitting downlink pilot signals depending on the uplink channel information.

[00139] The network device may estimate uplink channel information based on the uplink reference signal, thereby determining a beam. The beam determined by the network device is used to form beams when transmitting a downlink pilot signal. Optionally, the downlink pilot signal includes at least one of the following signals:

CSI-RS signal;

DMRS signal; or

a combination of CSI-RS and DMRS signals.

[00140] At step 406, the network device transmits downlink pilot signals to the terminal with beamforming at each of T consecutive times.

[00141] The downlink beamforming pilot signals are used by the terminal to determine the actual downlink information. T is a positive integer. Alternatively, the above parameter T is determined by at least one of the following methods:

configured by the network device; or

is pre-determined by negotiation between the terminal device and the network device.

[00142] Alternatively, the network device transmits downlink pilot signals to the terminal with beamforming at each of T consecutive times using the same pilot resource port and the same beam. The same pilot resource port includes a port corresponding to the same pilot resources or the same port indexed by different pilot resources.

[00143] Alternatively, the network device transmits different downlink pilot signals with beamforming to the terminal at each of T consecutive times using the same pilot resource port. The same pilot resource ports include ports with the same position in the frequency domain among ports configured with different pilot resources.

[00144] In step 408, the terminal estimates actual downlink channel information at each of T consecutive times based on downlink beamforming pilot signals received at each of T consecutive times.

[00145] Alternatively, the terminal may estimate actual information about the downlink channel at each of T consecutive times based on downlink beamforming pilot signals received at each of T consecutive times. The actual information about the downlink channel is used to determine the characteristics of the downlink channel.

[00146] In step 410, the terminal determines the first type CSI information corresponding to each of the T consecutive times based on the actual downlink channel information corresponding to each of the T consecutive times.

[00147] Based on the CSI information determined by the terminal, the network device may determine a precoding matrix for transmitting data on a downlink channel. The CSI information may also be referred to as codebook parameter information. Optionally, the CSI information includes at least one of the following elements:

indication of port selection;

indication information about the frequency domain basis vectors;

indication information about the Doppler component in the time domain; or

indication information about weighting factors.

[00148] The port selection indicator information is used to indicate L reference signal ports selectable by the terminal, the frequency domain basis vector indicator information is used to indicate M frequency domain basis vectors selectable by the terminal, the time domain Doppler component indicator information is used to indicate K time domain Doppler components selectable by the terminal, and the weighting coefficient indicator information is used to indicate weighting coefficients determined by the terminal. The parameter L, the parameter M, and the parameter K are positive integers. Alternatively, the time domain Doppler component indicator information is used to indicate K time domain basis vectors selectable by the terminal, or K phase shifts. That is, the time domain Doppler component is represented by a phase shift or a basis vector.

[00149] Alternatively, each of the above parameters K is determined in at least one of the following ways:

configured by the network device;

is predetermined by negotiation between the terminal device and the network device; or

determined by the terminal according to the downlink information.

[00150] Alternatively, the above-mentioned reference signal port includes at least one of the following ports:

CSI-RS port; or

DMRS port.

[00151] Alternatively, the above parameter K is determined in at least one of the following ways:

configured by the network device;

is predetermined by negotiation between the terminal device and the network device; or

is determined by the terminal according to the actual information about the downlink channel.

[00152] When the terminal determines the parameter K based on the actual downlink information, the terminal transmits the parameter K determined by it to the network device.

[00153] Alternatively, in the case where the parameter T and/or the parameter K are configured by the network device, the parameter T and/or the parameter K are configured by the network device for the terminal by means of at least one of the following types of signaling:

RRC signaling;

MAC-CE signaling; or

DCI signaling.

[00154] Alternatively, the Doppler component in the time domain satisfies at least one of the following conditions:

in the case where the data transmission in the downlink channel is carried out at the same level, the Doppler components in the time domain corresponding to different polarization directions coincide or differ;

the Doppler components in the time domain corresponding to different ports of the reference signal are the same or different; or

Doppler components in the time domain corresponding to different time-frequency components coincide or differ.

[00155] The time-frequency component consists of a frequency domain basis vector and a Doppler component in the time domain. Since there are usually two polarization directions, the Doppler components in the time domain corresponding to the two polarization directions are the same or different. The polarization direction mentioned above refers to the polarization direction in which the network device transmits data to the terminal.

[00156] Alternatively, in the case where the downlink data transmission is performed on multiple layers, the Doppler components in the time domain corresponding to the different transmission layers are the same or different. Multilayer transmission implies the presence of multiple transmission layers that are used by the network device to map code words to ports.

[00157] Alternatively, the Doppler component in the time domain is represented by a phase shift between adjacent times for transmitting downlink pilot signals. In the case where the Doppler component in the time domain is represented by a phase shift, then if the parameter K is determined by the terminal, this parameter K is determined by the terminal depending on the number of non-zero coefficients for each transmission level.

[00158] Alternatively, the Doppler component in the time domain is represented by a phase shift, and the expression for the Doppler component in the time domain is:

;

[00159] where e is the base of the natural logarithm and j is the imaginary number. - the value of the phase shift corresponding to the x-th port of the reference signal and the y-th frequency domain basis vector, the parameter L is the number of reference signal ports selected by the terminal, and the parameter M is the number of frequency domain basis vectors selected by the terminal. The parameter L and the parameter M are positive integers.

[00160] Alternatively, when the terminal provides the network device with information about the Doppler component in the time domain, the terminal reports a phase shift value corresponding to the x-th port of the reference signal and the y-th basis vector of the frequency domain that satisfies the following condition:

[00161] the amplitude of the weighting coefficient corresponding to the x-th port of the reference signal and the y-th basis vector of the frequency domain is not equal to 0.

[00162] Alternatively, the terminal may transmit the strongest coefficient to the network device.

[00163] In step 412, the terminal provides the network device with CSI information of the first type.

[00164] Alternatively, the terminal provides to the network device all or part of the CSI information determined by the terminal. The CSI information is used by the network device to calculate a precoding matrix for transmitting data on a downlink channel at a time t that occurs after T consecutive times. Alternatively, when providing the CSI information, the terminal may quantize the CSI information.

[00165] At step 414, the network device calculates a precoding matrix for transmitting data on a downlink channel at time t based on the first type of CSI information.

[00166] Alternatively, the network device calculates a precoding matrix for transmitting data on a downlink channel at each of T consecutive times based on the CSI information provided by the terminal as a precoding matrix at time t. The network device may also calculate the precoding matrix directly at time t based on the CSI information provided by the terminal.

[00167] For the situation where the network device calculates the precoding matrices at each of T consecutive time instances as the precoding matrix at time instance t

[00168] There is a correspondence between the Doppler components in the time domain and the time instances. Based on the CSI information provided by the terminal, the network device can calculate a precoding matrix corresponding to each of the T consecutive time instances using the following equation and determine it as a precoding matrix for downlink data transmission at time instance t:

;

[00169] where - port selection matrix corresponding to the reference signal port, - matrix of weighting coefficients, - matrix of frequency domain basis vectors, is the normalization factor, and H is the conjugate transpose of the matrix.

[00170] For the situation where the network device calculates the precoding matrix directly at time t

[00171] Alternatively, the time intervals between adjacent time instances among T consecutive time instances are equal, the time difference between time instance t and the first time instance of T consecutive time instances is Δt, where Δt is an integer multiple of the time interval between adjacent time instances among T consecutive time instances. Based on the CSI information provided by the terminal, the network device may calculate a precoding matrix for downlink data transmission directly at time instance t using the following equations:

;

;

[00172] where - port selection matrix corresponding to the reference signal port, - matrix of weighting coefficients, - matrix of frequency domain basis vectors, - normalization factor, parameter L is the number of reference signal ports selected by the terminal, parameter M is the number of frequency domain basis vectors selected by the terminal, where parameter L and parameter M are positive integers, and H is the conjugate transpose of the matrix.

[00173] In a specific example, a method proposed in an embodiment of the present invention is used to optimize a codebook structure of an R17 Type II port selection, and a Doppler component in the time domain is represented by a phase shift. A UE transmits an SRS to a gNB, and the gNB estimates uplink information based on the received SRS, calculates P spatial beams, and then transmits downlink pilot signals with beamforming to the UE through P CSI-RS ports. For example, FIG. 5 is a diagram of a method for transmitting a CSI-RS proposed in one embodiment of the present invention. As shown in FIG. 5, a downlink pilot signal used for downlink channel estimation is a CSI-RS signal. The gNB transmits a beamforming CSI-RS signal to the UE for two consecutive times T=2, and defines the transmitted beamforming CSI-RS signal as a beamforming CSI-RS packet, where the same port uses the same beam for beamforming. For example, the data is transmitted in one stream, i.e., the transmission rank is v=1, the number of transmit antenna ports is , and the number of PMI sub-ranges is . The gNB device configures the codebook parameters for the UE device using RRC signaling, specifying the parameter values L=2, M=1, and the number of non-zero coefficients .

[00174] The UE estimates the actual downlink information at two points in time based on the received CSI-RS packet with beamforming. For example, if the UE determines the port selection matrix in accordance with the actual information about the channel at the first moment in time (the first moment in time, i.e. the moment in time ) from two moments of time, the matrix turns off. The UE device is using to calculate the matrix of weighting coefficients based on the downlink information at the first time, with the amplitude of the weighting coefficient being greater than zero. The UE then uses the same matrix to calculate the matrix of weighting coefficients and the Doppler component in the time domain based on the information about the downlink at the second point in time (the second point in time, i.e. the point in time ) from two moments in time, where . The UE device provides the gNB device with matrix indication information (which is used to inform the gNB device about the matrix ), the quantized weight matrices and the quantized Doppler component in the time domain D. The gNB device computes the precoding matrices accordingly at time and at the moment of time according to the formula . The precoding matrices may be defined as the precoding matrix for downlink data transmission at time t occurring after T consecutive times. The gNB device may also calculate the precoding matrix at time t using the formula , Where , A - normalization factor. Δt - relative difference in time between time t and time , where Δt is an integer multiple of the relative time difference between the moment in time and the moment in time .

[00175] In a specific example, the method proposed in the embodiments of the present invention is used to optimize the structure of the R16 Type II port selection codebook, and the Doppler component in the time domain is represented by a phase shift. The UE transmits an SRS to the gNB, and the gNB estimates uplink channel information based on the received SRS, calculates P spatial beams, and then transmits downlink pilot signals with beamforming to the UE through P CSI-RS ports. For example, as shown in FIG. 5, the pilot signal used for downlink channel estimation is a CSI-RS. The gNB transmits CSI-RS packets with beamforming to the UEs at two consecutive times T=2, and the same port uses the same beam in beamforming. For example, data is transmitted in one stream, that is, the transmission rank v=1, the number of transmit antenna ports is , and the number of PMI sub-ranges is . The gNB device configures the codebook parameters for the UE device using RRC signaling, specifying the values of the parameters L=2, M=2, and the number of non-zero coefficients. .

[00176] The UE estimates the actual downlink channel information at two times based on the received CSI-RS packet with beamforming. For example, if the UE selects L = 2 ports in one polarization direction based on the channel information at the first time (the first time, i.e., time ) from two moments of time, and the UE device calculates the basis vector FD, it is possible to obtain matrices And . The UE device uses matrices And to calculate the matrix of weight coefficients at time t0, where , , And - complex numbers, and their amplitudes are greater than 0. Then the UE device uses the same matrices And to calculate the matrix of weight coefficients at the second moment in time (the second moment in time, i.e. the moment in time ) from two moments of time, and calculate the Doppler component in the time domain , Where . The UE device provides the gNB device with matrix indication information And , the quantized weight matrices and the quantized Doppler component in the time domain D. The gNB device computes the precoding matrices accordingly at time and the moment in time by formulas And . The precoding matrices can be used as the precoding matrix for downlink data transmission at time t occurring after T consecutive times. The gNB device can also calculate the precoding matrix at time t using the formula , Where , A , And - normalization factors. Δt is the relative time difference between the moment of time t and the moment of time t0, where Δt is an integer multiple of the relative time difference between the moment of time and the moment in time .

[00177] Thus, in the method proposed in this embodiment of the present invention, the terminal determines a Doppler component in the time domain from downlink beamforming pilot signals at each of T consecutive times, and in the process of determining the CSI information, correlation of channel information in the time domain can be taken into account. The network device uses the Doppler component in the time domain to determine a precoding matrix, which allows the network device to calculate the precoding matrix at different future times based on the CSI information provided by the terminal once. In addition to ensuring data transmission efficiency, this makes it possible to prevent the terminal from frequently providing CSI information due to its rapid movement, to shorten the period of providing CSI information by the terminal, and to reduce the amount of overhead data transmitted by the terminal in the uplink. Moreover, by using the downlink beamforming pilot signals, the accuracy of determining the CSI information can be improved. In addition, determining the Doppler component in the time domain represented by the phase shift provides a method for determining the Doppler component in the time domain.

[00178] 2. For the situation where the Doppler component in the time domain is represented by the basis vector, and the Doppler component in the time domain is determined by the terminal

[00179] Fig. 6 is a flow chart of a method for determining a precoding matrix proposed in one embodiment of the present invention. This method can be applied in the system shown in Fig. 1. The method includes the following sequence of actions.

[00180] In step 602, the terminal transmits an uplink reference signal to the network device.

[00181] Alternatively, the uplink reference signal is an SRS signal.

[001820] In step 604, the network device evaluates uplink channel information based on the uplink reference signal and determines a beam for transmitting a downlink pilot signal depending on the uplink channel information.

[00183] The network device may estimate uplink channel information based on the uplink reference signal, thereby determining a beam. The beam determined by the network device is used to form beams when transmitting a downlink pilot signal. Optionally, the downlink pilot signal includes at least one of the following signals:

CSI-RS signal;

DMRS signal; or

a combination of CSI-RS and DMRS signals.

[00184] At step 606, the network device transmits downlink pilot signals to the terminal with beamforming at each of T consecutive times.

[00185] The downlink beamforming pilot signals are used by the terminal to determine the actual downlink information. T is a positive integer. Alternatively, the above parameter T is determined by at least one of the following methods:

configured by the network device; or

is pre-determined by negotiation between the terminal device and the network device.

[00186] Alternatively, the network device transmits downlink pilot signals to the terminal with beamforming at each of T consecutive times using the same pilot resource port and the same beam. The same pilot resource port includes a port corresponding to the same pilot resources or the same port indexed by different pilot resources.

[00187] Alternatively, the network device transmits different downlink pilot signals with beamforming to the terminal at each of T consecutive times using the same pilot resource port. The same pilot resource ports include ports with the same position in the frequency domain among ports configured with different pilot resources.

[00188] In step 608, the terminal estimates actual downlink channel information at each of T consecutive times based on downlink beamforming pilot signals received at each of T consecutive times.

[00189] Alternatively, the terminal may estimate actual information about the downlink channel at each of T consecutive times based on downlink beamforming pilot signals received at each of T consecutive times. The actual information about the downlink channel is used to determine the characteristics of the downlink channel.

[00190] In step 610, the terminal determines the second type CSI information corresponding to each of the T consecutive times based on the actual downlink channel information corresponding to each of the T consecutive times.

[00191] Based on the CSI information determined by the terminal, the network device may determine a precoding matrix for transmitting data on a downlink channel. The CSI may also be referred to as codebook parameter information. Optionally, the CSI information includes at least one of the following elements:

indication of port selection;

indication information about the frequency domain basis vectors;

indication information about the Doppler component in the time domain; or

indication information about weighting factors.

[00192] The port selection indication information is used to indicate L reference signal ports selectable by the terminal, the frequency domain basis vector indication information is used to indicate M frequency domain basis vectors selectable by the terminal, the time domain Doppler component indication information is used to indicate K time domain Doppler components selectable by the terminal, and the weighting coefficient indication information is used to indicate weighting coefficients determined by the terminal. The parameter L, the parameter M, and the parameter K are positive integers. Alternatively, the time domain Doppler component indication information is used to indicate K time domain basis vectors selectable by the terminal, or K phase shifts. That is, the time domain Doppler component is represented by a phase shift or a basis vector.

[00193] Alternatively, each of the above parameters K is determined in at least one of the following ways:

configured by the network device;

is predetermined by negotiation between the terminal device and the network device; or

determined by the terminal according to the downlink information.

[00194] Alternatively, the above-mentioned reference signal port includes at least one of the following ports:

CSI-RS port; or

DMRS port.

[00195] Alternatively, the above parameter K is determined in at least one of the following ways:

configured by the network device;

is predetermined by negotiation between the terminal device and the network device; or

is determined by the terminal according to the actual information about the downlink channel.

[00196] When the terminal determines the parameter K based on the actual information about the downlink channel, the terminal transmits the parameter K determined by it to the network device.

[00197] Alternatively, in the case where the parameter T and/or the parameter K are configured by the network device, the parameter T and/or the parameter K are configured by the network device for the terminal by means of at least one of the following types of signaling:

RRC signaling;

MAC-CE signaling; or

DCI signaling.

[00198] Alternatively, the Doppler component in the time domain satisfies at least one of the following conditions:

in the case where the data transmission in the downlink channel is carried out at the same level, the Doppler components in the time domain corresponding to different polarization directions coincide or differ;

the Doppler components in the time domain corresponding to different ports of the reference signal are the same or different; or

Doppler components in the time domain corresponding to different time-frequency components coincide or differ.

[00199] The time-frequency component consists of a frequency domain basis vector and a Doppler component in the time domain. Since there are usually two polarization directions, the Doppler components in the time domain corresponding to the two polarization directions are the same or different. The polarization direction mentioned above refers to the polarization direction in which the network device transmits data to the terminal.

[00200] Alternatively, in the case where the downlink data transmission is performed on multiple layers, the Doppler components in the time domain corresponding to different transmission layers are the same or different. Multilayer transmission implies the presence of multiple transmission layers that are used by the network device to map code words to ports.

[00201] Alternatively, the Doppler component in the time domain is represented by a basis vector. The basis vector includes at least one of the following vectors:

DFT basis vector;

DCT basis vector;

polynomial basis vector.

[00202] Alternatively, by introducing the parameter O ₃ , the Doppler component can be resampled in the time domain to obtain additional information about the basis vector.

[00203] Alternatively, the Doppler component in the time domain is represented by a basis vector. The expression for the Doppler component in the time domain is as follows:

;

[00204] where K are the basis vectors in the matrix are selected by the terminal from possible basis vectors; or K basis vectors in the matrix are fixed or predetermined basis vectors. Alternatively, the terminal communicates the selected K time-domain Doppler components to the network device using weights or bitmaps.

[00205] In step 612, the terminal provides the network device with the second type of CSI information.

[00206] Alternatively, the terminal may provide the network device with all or part of the CSI information determined by the terminal. The CSI information is used by the network device to calculate a precoding matrix for transmitting data on a downlink channel at a time t that occurs after T consecutive times. Alternatively, when providing the CSI information, the terminal quantizes the CSI information.

[00207] At step 614, the network device calculates a precoding matrix for data transmission on a downlink channel at time t based on the second type CSI information.

[00208] Alternatively, the network device calculates a precoding matrix for transmitting data on a downlink channel at each of T consecutive times based on the CSI information provided by the terminal as a precoding matrix at time t. The network device may also calculate the precoding matrix directly at time t based on the CSI information provided by the terminal.

[00209] For a situation where the network device calculates the precoding matrix at each of T consecutive times as the precoding matrix at time t

[00210] There is a correspondence between the Doppler components in the time domain and the time instances. Based on the CSI information provided by the terminal, the network device can calculate a precoding matrix corresponding to each time instance of T consecutive time instances using the following equation and determine it as a precoding matrix for downlink data transmission at time instance t:

;

[00211] where - port selection matrix corresponding to the reference signal port, - matrix of weighting coefficients, - matrix of frequency domain basis vectors, is the normalization factor, and H is the conjugate transpose of the matrix.

[00212] For the situation where the network device calculates the precoding matrix directly at time t

[00213] Alternatively, the Doppler component in the time domain is represented by a DFT basis vector. The intervals between adjacent instants among T consecutive instants are t=T+n, which means that the instant t occurs after the last instant among T instants, and the interval from the last instant among T instants is n target time intervals. The target time interval is the interval between adjacent instants among T consecutive instants, and n is a positive integer. Based on the CSI information provided by the terminal, the network device can calculate a precoding matrix for downlink data transmission directly at the instant t using the following equation:

;

[00214] where - port selection matrix corresponding to the reference signal port, - matrix of weighting coefficients, - matrix of frequency domain basis vectors, - elements in the T-th row of the DFT basis vector, - the value of the index of the K-th basis vector of the DFT, is the normalization factor, O ₃ is the resampling coefficient, and H is the conjugate transpose of the matrix.

[00215] In a specific example, a method proposed in an embodiment of the present invention is used to optimize the structure of an R17 Type II port selection codebook, and the Doppler component in the time domain is represented by a basis vector. The UE transmits an SRS to the gNB, and the gNB estimates uplink channel information based on the received SRS, calculates P spatial beams, and then transmits downlink pilot signals with beamforming to the UE through P CSI-RS ports. For example, FIG. 7 is a diagram of a method for transmitting a CSI-RS signal proposed in one embodiment of the present invention. As shown in FIG. 7, the pilot signal used for downlink channel estimation is a CSI-RS. The gNB transmits CSI-RS packets with beamforming to the UE at four consecutive times T=4. The same port uses the same beam in beamforming. For example, data is transmitted in one stream, i.e. the transmission rank is v=1, the number of ports of the transmitting antenna is , and the number of PMI sub-ranges . The gNB device configures the codebook parameters for the UE device using RRC signaling, defining the values of the parameters L=2, M=2 and the number of weights to be transmitted. . The Doppler component in the time domain is represented by K=2 DFT basis vectors, while no resampling is performed for the basis vector of the Doppler component in the time domain, i.e. the parameter , corresponding to the basis vector of the DFT, is equal to 1.

[00216] The UE estimates the actual downlink channel information at these four times based on the received CSI-RS packets. For example, if the port selected by the UE based on the channel information at the first time (the first time, i.e., time ) among four moments in time, is presented as , matrix is represented by basis vectors FD in the quantity M=2. The UE device uses matrices And to calculate the matrix of weighting coefficients based on the downlink information at the first time. Similarly, the UE device uses the same matrices And for calculating matrices of weight coefficients , And , corresponding to the three remaining moments of time except the first. Matrix is represented by definition . Similarly, can be obtained , And . , then the Doppler component in the time domain can be defined as . The UE device may determine weighting factors based on the actual information about the downlink channel at each of T consecutive moments of time and matrices , And , and then non-zero coefficients are selected for transmission in the amount . The UE device provides the gNB device with matrix indication information And , quantized weighting matrices and the Doppler component in the time domain . The gNB device can calculate the precoding matrix corresponding to each moment among T consecutive moments of time using the expression . The precoding matrices can be used as a precoding matrix for downlink data transmission at time t occurring after T consecutive times. In addition, the gNB device can also calculate the precoding matrix at time t using the expression , where t=T+n, which means that the time moment t occurs after the last moment among T time moments, and the interval from the last moment among T time moments is n target time intervals. The target time interval is the interval between adjacent moments among T consecutive time moments. The expression represents the elements corresponding to the T-th row of the basis vector.

[00217] It should be noted that the method proposed in the embodiments of the present invention can also be used to optimize the structure of the R16 Type II port selection codebook, and the Doppler component in the time domain is represented by a basis vector. In a specific implementation, reference can be made to the above embodiments in which the R17 Type II port selection codebook is optimized, and the Doppler component in the time domain is represented by a basis vector. Details are not given here.

[00218] Thus, in the method proposed in this embodiment of the present invention, the terminal determines a Doppler component in the time domain from downlink beamforming pilot signals at each of T consecutive times, and the correlation of channel information in the time domain can be taken into account in the process of determining the CSI information. The network device uses the Doppler component in the time domain to determine a precoding matrix, which allows the network device to calculate the precoding matrix at different future times based on the CSI information provided by the terminal once. In addition to ensuring data transmission efficiency, this makes it possible to prevent the terminal from frequently providing CSI information due to its rapid movement, to shorten the period of providing CSI information by the terminal, and to reduce the amount of overhead data transmitted by the terminal in the uplink. Moreover, by using the downlink beamforming pilot signals, it is possible to improve the accuracy of determining the CSI information. In addition, determining the Doppler component in the time domain represented by the basis vector provides a method for determining the Doppler component in the time domain.

[00219] 3. For the situation where the Doppler component in the time domain is determined by the network device

[00220] Fig. 8 is a flow chart of a method for determining a precoding matrix proposed in one embodiment of the present invention. This method can be applied in the system shown in Fig. 1. The method includes the following sequence of actions.

[00221] In step 802, the terminal transmits an uplink reference signal to the network device.

[00222] Alternatively, the uplink reference signal is an SRS signal.

[00223] In step 804, the network device evaluates uplink channel information based on the uplink reference signal and determines a beam for transmitting a downlink pilot signal depending on the uplink channel information.

[00224] The network device may estimate uplink channel information based on the uplink reference signal, thereby determining a beam. The beam determined by the network device is used to form beams when transmitting a downlink pilot signal. Optionally, the downlink pilot signal includes at least one of the following signals:

CSI-RS signal;

DMRS signal; or

a combination of CSI-RS and DMRS signals.

[00225] At step 806, the network device transmits downlink pilot signals to the terminal with beamforming at each of T consecutive times.

[00226] The downlink beamforming pilot signals are used by the terminal to determine the actual downlink information. T is a positive integer. Alternatively, the above parameter T is determined by at least one of the following methods:

configured by the network device; or

is pre-determined by negotiation between the terminal device and the network device.

[00227] Alternatively, the network device transmits downlink pilot signals to the terminal with beamforming at each of T consecutive times using the same pilot resource port and the same beam. The same pilot resource port includes a port corresponding to the same pilot resources or the same port indexed by different pilot resources.

[00228] Alternatively, the network device transmits different downlink pilot signals with beamforming to the terminal at each of T consecutive times using the same pilot resource port. The same pilot resource ports include ports with the same position in the frequency domain among ports configured with different pilot resources.

[00229] In step 808, the terminal estimates actual downlink channel information at each of T consecutive times based on downlink beamforming pilot signals received at each of T consecutive times.

[00230] Alternatively, the terminal may estimate actual downlink channel information at each of T consecutive times based on downlink beamforming pilot signals received at each of T consecutive times. The actual downlink channel information is used to determine downlink channel characteristics.

[00231] In step 810, the terminal determines the third type CSI information corresponding to each of the T consecutive times based on the actual downlink channel information corresponding to each of the T consecutive times.

[00232] Based on the CSI information determined by the terminal, the network device may determine a precoding matrix for transmitting data on a downlink channel. The CSI may also be referred to as codebook parameter information. Optionally, the CSI information includes at least one of the following elements:

indication of port selection;

indication information about the frequency domain basis vectors; or

indication information about weighting factors.

[00233] The indication information about port selection is used to indicate L ports of the reference signal selected by the terminal, the indication information about frequency domain basis vectors is used to indicate M frequency domain basis vectors selected by the terminal, and the indication information about weight coefficients is used to indicate T groups of weight coefficients corresponding to T consecutive time instants determined by the terminal. The information about the positions of the non-zero coefficients in the matrices of the T groups of weight coefficients is the same, and the parameter L and the parameter M are positive integers.

[00234] Alternatively, each of the above parameters K is determined in at least one of the following ways:

configured by the network device;

is predetermined by negotiation between the terminal device and the network device; or

determined by the terminal according to the downlink information.

[00235] Alternatively, in the case where the parameter T is configured by the network device, the parameter T is configured by the network device for the terminal by means of at least one of the following types of signaling:

·RRC signaling;

·MAC-CE signaling; or

·DCI signaling.

[00236] Alternatively, the above-mentioned reference signal port includes at least one of the following ports:

·CSI-RS port; or

·DMRS port.

[00237] In step 812, the terminal provides the network device with CSI information of the third type.

[00238] Alternatively, the terminal may provide the network device with all or part of the CSI information determined by the terminal. The CSI information is used by the network device to calculate a precoding matrix for transmitting data on a downlink channel at a time t that occurs after T consecutive times. Alternatively, when providing the CSI information, the terminal quantizes the CSI information.

[00239] At step 814, the network device calculates a precoding matrix for data transmission on a downlink channel at time t based on the third type of CSI information.

[00240] Alternatively, the network device calculates a precoding matrix for transmitting data on a downlink channel at each of T consecutive times based on the CSI information provided by the terminal as a precoding matrix at time t. Alternatively, the network device may calculate a precoding matrix for transmitting data on a downlink channel at time t based on the CSI information provided by the terminal using one of the following equations:

;

;

[00241] where - port selection matrix corresponding to the reference signal port, And - matrices of weighting coefficients, - a matrix of frequency domain basis vectors, where D includes the Doppler components in the time domain, represented by phase shifts between adjacent time instants for the transmission of downlink pilot signals with beamforming, includes Doppler components in the time domain, represented by basis vectors, , , And are determined by T groups of weighting coefficients, And - normalization factors, and H is the conjugate transpose of the matrix.

[00242] Thus, in the method proposed in this embodiment of the present invention, the terminal determines T groups of weight coefficients based on downlink beamforming pilot signals at each of T consecutive times and provides CSI information to a network device that can take into account the correlation of channel information in the time domain in the process of determining the CSI. The network device determines a precoding matrix by determining a Doppler component in the time domain, which allows the network device to calculate the precoding matrix at different future times based on the CSI information provided by the terminal once. In addition to ensuring data transmission efficiency, this makes it possible to prevent the terminal from frequently providing CSI information due to its rapid movement, to shorten the period of providing CSI information by the terminal, and to reduce the amount of overhead data transmitted by the terminal in the uplink. Moreover, by using the downlink beamforming pilot signals, it is possible to improve the accuracy of determining the CSI information. In addition, because the network device can detect the Doppler component in the time domain, it is possible to further reduce the amount of service information transmitted by the terminal over the uplink channel.

[00243] It should be noted that the sequence of method steps proposed in the embodiments of the present invention can be appropriately adjusted, and steps can also be added or excluded depending on the specific situation. Modified methods that those skilled in the art can easily find within the framework of the technical solutions presented in the present invention should be included in the scope of protection of the present invention, and therefore their description is not repeated here.

[00244] Fig. 9 is a block diagram of an apparatus for providing CSI information proposed in one embodiment of the present invention. As shown in Fig. 9, the apparatus includes the following components:

[00245] a transmitting module 901 configured to transmit an uplink reference signal to a network device;

[00246] a receiving module 902 configured to receive downlink beamforming pilot signals transmitted by the network device at each of T consecutive times; and

[00247] a determining module 903 configured to estimate actual downlink channel information at each of T consecutive times based on downlink beamforming pilot signals received at each of T consecutive times.

[00248] The determining module 903 is further configured to determine CSI information corresponding to each of the T consecutive times based on actual downlink channel information at each of the T consecutive times.

[00249] The transmitting module is further configured to provide CSI information to the network device.

[00250] A beam used for downlink beamforming pilot signals is determined based on uplink channel information estimated from an uplink reference signal, wherein the CSI information is used by the network device in determining a precoding matrix for downlink data transmission at time t, wherein time t occurs after T consecutive times, and T is a positive integer.

[00251] In one possible embodiment, the CSI information includes at least one of the following elements:

[00252] indication information about the selection of ports;

[00253] indication information about the frequency domain basis vectors;

[00254] indication information about the Doppler component in the time domain; or

[00255] weighting coefficient indicator information.

[00256] The port selection indication information is used to indicate L reference signal ports selected by the terminal, the frequency domain basis vector indication information is used to indicate M frequency domain basis vectors selected by the terminal, the time domain Doppler component indication information is used to indicate K time domain Doppler components selected by the terminal, and the weight coefficient indication information is used to indicate weight coefficients determined by the terminal, wherein the L parameter, the M parameter and the K parameter are positive integers.

[00257] Alternatively, the CSI information includes at least one of the following elements:

[00258] indication information about the selection of ports;

[00259] indication information about the frequency domain basis vectors; or

[00260] weighting information.

[00261] The port selection indication information is used to indicate L reference signal ports selected by the terminal, the frequency domain basis vector indication information is used to indicate M frequency domain basis vectors selected by the terminal, and the weight coefficient indication information is used to indicate T groups of weight coefficients corresponding to T consecutive time instants determined by the terminal, wherein the information about the positions of the non-zero coefficients in the matrices of the T groups of weight coefficients is the same, and the parameter L and the parameter M are positive integers.

[00262] Alternatively, the parameter K is determined in at least one of the following ways:

[00263] configured by the network device;

[00264] is predetermined by negotiation between the terminal device and the network device; or

[00265] is determined by the terminal according to the actual downlink information.

[00266] Alternatively, the transmitting module 901 is configured to:

[00267] in the case where the terminal determines the parameter K based on the actual information about the downlink channel, transmit the parameter K determined by it to the network device.

[00268] Alternatively, the Doppler component in the time domain is represented by a phase shift between adjacent times for transmitting downlink pilot signals; or the Doppler component in the time domain is represented by a basis vector.

[00269] Alternatively, in the case where the Doppler component in the time domain is represented by a phase shift, the parameter K is determined by the terminal depending on the number of non-zero coefficients for each transmission level.

[00270] Alternatively, the Doppler component in the time domain satisfies at least one of the following conditions:

[00271] in the case where the data transmission in the downlink channel is carried out at one level, the Doppler components in the time domain corresponding to different polarization directions coincide or differ;

[00272] the Doppler components in the time domain corresponding to different ports of the reference signal are the same or different; or

[00273] Doppler components in the time domain corresponding to different time-frequency components coincide or differ.

[00274] The time-frequency component consists of a frequency domain basis vector and a Doppler component in the time domain.

[00275] Alternatively, in the case where the downlink data transmission is performed on multiple levels, the Doppler components in the time domain corresponding to the different transmission levels are the same or different.

[00276] Alternatively, the Doppler component in the time domain is represented by a basis vector. The expression for the Doppler component in the time domain is as follows:

;

[00277] where - the value of the phase shift corresponding to the x-th port of the reference signal and the y-th frequency domain basis vector, the parameter L is the number of reference signal ports selected by the terminal, and the parameter M is the number of frequency domain basis vectors selected by the terminal, wherein the parameter L and the parameter M are positive integers.

[00278] Alternatively, the transmitting module 901 is configured to:

[00279] when the terminal provides the network device with information about the Doppler component in the time domain, report a phase shift value corresponding to the x-th port of the reference signal and the y-th basis vector of the frequency domain that satisfies the following condition:

[00280] the amplitude of the weighting coefficient corresponding to the x-th port of the reference signal and the y-th basis vector of the frequency domain is not equal to 0.

[00281] Alternatively, the Doppler component in the time domain is represented by a basis vector, where the expression for the Doppler component in the time domain is:

;

[00282] where K are the basis vectors in the matrix are selected by the terminal from possible basis vectors; or K basis vectors in the matrix are fixed or predetermined basis vectors.

[00283] Alternatively, the Doppler component in the time domain is represented by a basis vector, wherein the basis vector includes at least one of the following vectors:

[00284] DFT basis vector;

[00285] DCT basis vector; or

[00286] polynomial basis vector.

[00287] Alternatively, the parameter T is determined in at least one of the following ways:

[00288] configured by the network device; or

[00089] is predetermined by negotiation between the terminal device and the network device.

[00290] Alternatively, in the case where the parameter T and/or the parameter K are configured by the network device, the parameter T and/or the parameter K are configured by the network device for the terminal by means of at least one of the following types of signaling:

[00291] RRC signaling;

[00292] MAC-CE signaling; or

[00293] DCI signaling.

[00294] Alternatively, the reference signal port includes at least one of the following ports:

[00295] CSI-RS port; or

[00296] DMRS port.

[00297] Alternatively, the downlink pilot signal includes at least one of the following signals:

[00298] CSI-RS signal;

[00299] DMRS signal; or

[00300] combination of CSI-RS and DMRS.

[00301] Alternatively, the uplink reference signal is an SRS signal.

[00302] Fig. 10 is a block diagram of an apparatus for determining a precoding matrix proposed in one embodiment of the present invention. As shown in Fig. 10, the apparatus includes the following components:

[00303] a receiving module 1001 configured to receive an uplink reference signal transmitted by a terminal;

[00304] a determining module 1002 configured to estimate uplink channel information based on an uplink reference signal and determine a beam for transmitting downlink pilot signals depending on the uplink channel information; and

[00305] a transmitting module 1003 configured to transmit downlink pilot signals to the terminal with beamforming at each of T consecutive times.

[00306] The receiving module 1001 is further used to receive CSI information provided by the terminal corresponding to each of the T consecutive time instances.

[00307] The determining module 1002 is further used to determine a precoding matrix for data transmission on a downlink channel at time t taking into account the CSI information.

[00308] The CSI information is determined by the terminal based on downlink pilot signals with beamforming, and time t occurs after T consecutive time instants, and T is a positive integer.

[00309] Alternatively, the transmitting module 1003 is used such that:

[00310] transmit downlink pilot signals to the terminal with beamforming at each of T consecutive times using the same pilot resource port and the same beam;

[00311] wherein the same pilot signal resource port includes a port corresponding to the same pilot signal resources, or the same port indexed by different pilot signal resources.

[00312] Alternatively, the transmitting module 1003 is configured to:

[00313] transmit different downlink pilot signals with beamforming to the terminal at each of T consecutive times using the same pilot signal resource port;

[00314] wherein the same pilot signal resource port includes ports with the same position in the frequency domain among ports configured with different pilot signal resources.

[00315] Alternatively, the CSI information includes at least one of the following elements:

[00316] indication information about the selection of ports;

[00317] indication information about the frequency domain basis vectors;

[00318] indication information about the Doppler component in the time domain; or

[00319] weighting coefficient indicator information.

[00320] The port selection indication information is used to indicate L reference signal ports selected by the terminal, the frequency domain basis vector indication information is used to indicate M frequency domain basis vectors selected by the terminal, the time domain Doppler component indication information is used to indicate K time domain Doppler components selected by the terminal, and the weight coefficient indication information is used to indicate weight coefficients determined by the terminal, wherein the L parameter, the M parameter and the K parameter are positive integers.

[00321] Alternatively, the CSI information includes at least one of the following elements:

[00322] indication information about the selection of ports;

[00323] indication information about the frequency domain basis vectors; or

[00324] weighting information;

[00325] The port selection indication information is used to indicate L reference signal ports selected by the terminal, the frequency domain basis vector indication information is used to indicate M frequency domain basis vectors selected by the terminal, and the weight coefficient indication information is used to indicate T groups of weight coefficients corresponding to T consecutive time instants determined by the terminal, wherein the information about the positions of the non-zero coefficients in the matrices of the T groups of weight coefficients is the same, and the parameter L and the parameter M are positive integers.

[00326] Alternatively, the Doppler component in the time domain is represented by a phase shift between adjacent times for transmitting downlink pilot signals; or the Doppler component in the time domain is represented by a basis vector.

[00327] Alternatively, the Doppler component in the time domain is represented by a phase shift. The expression for the Doppler component in the time domain is as follows:

;

[00328] where - the value of the phase shift corresponding to the x-th port of the reference signal and the y-th frequency domain basis vector, the parameter L is the number of reference signal ports selected by the terminal, and the parameter M is the number of frequency domain basis vectors selected by the terminal. The parameter L and the parameter M are positive integers.

[00329] Alternatively, the Doppler component in the time domain is represented by a basis vector, where the expression for the Doppler component in the time domain is:

;

[00330] where K are the basis vectors in the matrix are selected by the terminal from possible basis vectors; or K basis vectors in the matrix are fixed or predetermined basis vectors.

[00331] Alternatively, the determining module 1002 is configured to:

[00332] determine a precoding matrix for downlink data transmission at time t taking into account the CSI information using the formula:

;

[00333] where - port selection matrix corresponding to the reference signal port, - matrix of weighting coefficients, - matrix of frequency domain basis vectors, is the normalization factor, and H is the conjugate transpose of the matrix.

[00334] Alternatively, the determining module 1002 is configured to:

[00335] determine a precoding matrix for downlink data transmission at time t taking into account the CSI information using the formula:

;

[00336] where - port selection matrix corresponding to the reference signal port, - matrix of weighting coefficients, - matrix of frequency domain basis vectors, is the normalization factor, and H is the conjugate transpose of the matrix.

[00337] Alternatively, the determining module 1002 is configured to:

[00338] determine a precoding matrix for downlink data transmission at time t taking into account the CSI information using at least one of the following formulas:

;

;

[00339] where - port selection matrix corresponding to the reference signal port, And - matrices of weighting coefficients, - a matrix of frequency domain basis vectors, where D includes the Doppler components in the time domain, represented by phase shifts between adjacent time instants for the transmission of downlink pilot signals with beamforming, includes Doppler components in the time domain, represented by basis vectors, , , And are determined by T groups of weighting coefficients, And - normalization factors, and H is the conjugate transpose of the matrix.

[00340] Alternatively, the time intervals between adjacent instants of time among T consecutive instants of time are equal, the time difference between instant of time t and the first instant of time among T consecutive instants of time is Δt, wherein Δt is an integer multiple of the time interval between adjacent instants of time among T consecutive instants of time. The determining module 1002 is configured such that:

[00341] determine a precoding matrix for downlink data transmission at time t taking into account the CSI information using the following formulas:

;

;

[00342] where - port selection matrix corresponding to the reference signal port, - matrix of weighting coefficients, - matrix of frequency domain basis vectors, - normalization factor, parameter L is the number of reference signal ports selected by the terminal, parameter M is the number of frequency domain basis vectors selected by the terminal, where parameter L and parameter M are positive integers, and H is the conjugate transpose of the matrix.

[00343] Alternatively, the Doppler component in the time domain is represented by a basis vector of a discrete Fourier transform (DFT), and the intervals between adjacent instants among T consecutive instants of time are equal to t=T+n, which means that the instant of time t occurs after the last instant among T instants of time, in which case the interval from the last instant among T instants of time is n target time intervals. The target time interval is the interval between adjacent instants among T consecutive instants of time, and n is a positive integer. The determining module 1002 is configured such that:

[00344] determine a precoding matrix for downlink data transmission at time t taking into account the CSI information using the formula:

;

[00345] where - port selection matrix corresponding to the reference signal port, - matrix of weighting coefficients, - matrix of frequency domain basis vectors, - elements in the T-th row of the DFT basis vector, - the value of the index of the K-th basis vector of the DFT, is the normalization factor, O ₃ is the resampling coefficient, and H is the conjugate transpose of the matrix.

[00346] Alternatively, the reference signal port includes at least one of the following ports:

[00347] CSI-RS port; or

[00348] DMRS port.

[00349] Alternatively, the downlink pilot signal includes at least one of the following signals:

[00350] CSI-RS signal;

[00351] DMRS signal; or

[00352] combination of CSI-RS and DMRS.

[00353] Alternatively, the uplink reference signal is an SRS signal.

[00354] It should be noted that when the device proposed in the above-described embodiment implements its functions, the functional modules are divided only as an example for illustration. In reality, the above-mentioned functions can be distributed among various functional modules depending on actual needs. In other words, the content structure of the device is divided into various functional modules to perform all or part of the above-described functions.

[00355] Since the description of the embodiments of the method describes in detail the features of performing operations by each module, their detailed description is not given here.

[00356] Fig. 11 shows a block diagram of a communication device (terminal or network device) proposed in one embodiment of the present invention. The communication device 110 includes: a processor 1101, a receiver 1102, a transmitter 1103, a memory 1104 and a bus 1105.

[00357] The processor 1101 includes one or more cores. The processor 1101 executes various functional applications and processes information by executing programs and modules.

[00358] Receiver 1102 and transmitter 1103 may be implemented as a communication component, which may be a communication chip.

[00359] Memory 1104 is coupled to processor 1101 via bus 1105.

[00360] Memory 1104 may be used to store at least one instruction, and processor 1101 may be used to execute at least one instruction for the purpose of performing each step in the above-described embodiments of the method.

[00361] In addition, the memory 1104 can be implemented as volatile or nonvolatile memory devices of any type or combinations thereof, which can be, among other things: magnetic or optical disks, electrically erasable programmable read-only memory (EEPROM, Electrically Erasable Programmable Read-Only Memory), erasable programmable read-only memory (EPROM, Erasable Programmable Read-Only Memory), static RAM (SRAM, Static Random Access Memory), ROM, magnetic memory, flash memory, PROM.

[00362] If the communication device is implemented as a terminal, the processor and the transceiver in the communication device used in the embodiments of the present invention may be implemented together as a communication chip, or the transceiver forms a separate communication chip. The transmitter in the transceiver performs the transmission operation performed by the terminal in any of the above-described embodiments of the method, the receiver in the transceiver performs the reception operation performed by the terminal in any of the above-described embodiments of the method, and the processor performs other operations, except for the transmission and reception operations, which are not described here.

[00363] If the communication device is implemented as a network device, the processor and the transceiver in the communication device used in the embodiments of the present invention may be implemented together as a communication chip, or the transceiver forms a separate communication chip. The transmitter in the transceiver performs the transmission operation performed by the network device in any of the above-described embodiments of the method, the receiver in the transceiver performs the reception operation performed by the network device in any of the above-described embodiments of the method, and the processor performs other operations, except for the transmission and reception operations, which are not described here.

[00364] In one embodiment, a computer-readable storage medium is also provided, on which at least one instruction, at least one program, set of codes, or set of instructions is stored, and at least one instruction, at least one program, set of codes, or set of instructions is loaded and executed by a processor to implement the method for providing CSI information or the method for determining a precoding matrix, proposed in any of the above-described embodiments of the method.

[00365] In one embodiment, a microcircuit is also proposed. The microcircuit includes programmable logic circuits and/or program instructions. When the microcircuit operates in a communication device, it is used to implement a method for providing CSI information or a method for determining a precoding matrix proposed in any of the above-described embodiments of the method.

[00366] In one embodiment, a computer program product is also provided. When the computer program product is executed on a processor of a computer device, the computer device implements the above-mentioned method for providing CSI information or the method for determining a precoding matrix.

[00367] Those skilled in the art will appreciate that the functions described in embodiments of the present invention, in one or more examples, may be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, the functions may be stored on or transmitted over by a computer-readable storage medium as one or more instructions or code. Computer-readable storage medium includes computer storage media and communication media, including any medium that enables transfer of a computer program from one place to another. The storage medium may use any available medium that can be accessed by a general-purpose or special-purpose computer.

[00368] The above description includes only some possible embodiments of the present invention and does not impose limitations on the present invention. Any modifications, equivalent replacements, improvements and other changes made in accordance with the principles of the present invention are included in the scope of the present invention.

Claims (74)

1. A method for providing channel state information (CSI) implemented by a terminal, which includes: transmitting an uplink reference signal to a network device; receiving downlink pilot signals with beamforming transmitted by the network device at each of T consecutive moments in time; estimating actual downlink information at each of T consecutive times based on beamformed downlink pilot signals received at each of T consecutive times; determining CSI information corresponding to each of T consecutive times based on actual downlink information at each of T consecutive times; and providing CSI information to a network device, wherein the CSI includes indication information about frequency domain basis vectors, wherein the indication information about frequency domain basis vectors is used to indicate M frequency domain basis vectors selectable by the terminal, wherein the parameter M is a positive integer; wherein the beam used for the downlink beamforming pilot signals is determined based on the uplink channel information estimated from the uplink reference signal, wherein the CSI information is used by the network device in determining a precoding matrix for transmitting data on the downlink channel at time t, wherein time t occurs after T consecutive times, where T is a positive integer. 2. The method according to claim 1, wherein the CSI information includes at least one of the following elements: indication of port selection; indication information about the Doppler component in the time domain; or indication information about weighting factors; wherein the port selection indication information is used to indicate L reference signal ports selected by the terminal, the time domain Doppler component indication information is used to indicate K time domain Doppler components selected by the terminal, and the weight coefficient indication information is used to indicate weight coefficients determined by the terminal, wherein the parameter L and the parameter K are positive integers. 3. The method according to claim 2, wherein the parameter K is determined by at least one of the following methods: configured by the network device; is predetermined by negotiation between the terminal device and the network device; or is determined by the terminal according to the actual information about the downlink channel. 4. The method according to claim 2, wherein the Doppler component in the time domain is represented by a basis vector, and the expression for the Doppler component in the time domain has the form: ; where the K basis vectors in matrix W _d are chosen by the terminal from the possible basis vectors; or the K basis vectors in matrix W _d are fixed or predetermined basis vectors. 5. The method according to claim 2, wherein the Doppler component in the time domain is represented by a basis vector, wherein the basis vector includes at least one of the following vectors: basis vector of the discrete Fourier transform (DFT); basis vector of the discrete cosine transform (DCT); or polynomial basis vector. 6. The method according to any one of paragraphs 1-5, in which the parameter T is determined by at least one of the following methods: configured by the network device; or is pre-determined by negotiation between the terminal device and the network device. 7. The method according to any one of paragraphs 2-5, wherein, in the case when the parameter T and/or the parameter K are configured by the network device, the parameter T and/or the parameter K are configured by the network device for the terminal by means of at least one of the following types of signaling: Radio Resource Control (RRC) signaling; medium access control element (MAC-CE) signaling; or Downlink Control Information (DCI). 8. The method according to any one of paragraphs 2-5, in which the reference signal port includes at least one of the following ports: channel state information reference signal (CSI-RS) port; or Demodulation Reference Signal (DMRS) port. 9. The method according to any one of paragraphs 1-8, wherein the downlink pilot signal includes at least one of the following signals: Channel State Information Reference Signal (CSI-RS); demodulation reference signal (DMRS); or a combination of CSI-RS and DMRS signals. 10. A method for determining a pre-coding matrix implemented by a network device, which includes: receiving an uplink reference signal transmitted by the terminal; estimating uplink information based on an uplink reference signal and determining a beam for transmitting downlink pilot signals depending on the uplink information; transmitting downlink pilot signals to the terminal with beamforming at each of T consecutive moments in time; receiving channel state information (CSI) provided by the terminal corresponding to each of T consecutive times, wherein the CSI includes indication information about frequency domain basis vectors, wherein the indication information about frequency domain basis vectors is used to indicate M frequency domain basis vectors selected by the terminal, wherein the parameter M is a positive integer; and determining a precoding matrix for downlink data transmission at time t taking into account the CSI information; wherein the CSI information is determined by the terminal based on downlink pilot signals with beamforming, and the time instant t occurs after T consecutive times, where T is a positive integer. 11. The method of claim 10, wherein the CSI information includes at least one of the following elements: indication of port selection; indication information about the Doppler component in the time domain; or indication information about weighting factors; wherein the port selection indication information is used to indicate L reference signal ports selected by the terminal, the time domain Doppler component indication information is used to indicate K time domain Doppler components selected by the terminal, and the weight coefficient indication information is used to indicate weight coefficients determined by the terminal, wherein the parameter L and the parameter K are positive integers. 12. The method according to claim 11, wherein the Doppler component in the time domain is represented by a basis vector, and the expression for the Doppler component in the time domain has the form: ; where the K basis vectors in matrix W _d are chosen by the terminal from the possible basis vectors; or the K basis vectors in matrix W _d are fixed or predetermined basis vectors. 13. The method according to claim 12, wherein the Doppler component in the time domain is represented by a basis vector of a discrete Fourier transform (DFT), and the intervals between adjacent moments among T consecutive moments of time are equal to t=T+n, which means that the moment of time t occurs after the last moment among T moments of time, wherein the interval from the last moment among T moments of time is n target time intervals, wherein the target time interval is the interval between adjacent moments among T consecutive moments of time, where n is a positive integer; and the determination of the precoding matrix for downlink data transmission at time t taking into account the CSI information includes: determination of the precoding matrix for data transmission over the downlink channel at time t taking into account the CSI information using the formula: ; Where - port selection matrix corresponding to the reference signal port, - matrix of weighting coefficients, - matrix of frequency domain basis vectors, - elements in the T-th row of the DFT basis vector, - the value of the index of the K-th basis vector of the DFT, is the normalization factor, O ₃ is the resampling coefficient, and H is the conjugate transpose of the matrix. 14. The method according to any one of paragraphs 11-13, in which the reference signal port includes at least one of the following ports: channel state information reference signal (CSI-RS) port; or Demodulation Reference Signal (DMRS) port. 15. The method according to any one of paragraphs 10-14, wherein the downlink pilot signal includes at least one of the following signals: Channel State Information Reference Signal (CSI-RS); demodulation reference signal (DMRS); or a combination of CSI-RS and DMRS signals. 16. A terminal containing: CPU; a transceiver connected to the processor; memory for storing instructions executed by the processor; wherein the processor is configured to load and execute executable instructions for implementing the method for providing CSI information according to any one of paragraphs 1-9. 17. A network device comprising: CPU; a transceiver connected to the processor; memory for storing instructions executed by the processor; wherein the processor is configured to load and execute executable instructions for implementing the method for determining a pre-coding matrix according to any one of paragraphs 10-15.