Communication method and communication device

Abstract

The present application provides a communication method and a communication device. In the method, a first device receives reference signals, frequency domain positions of the reference signals and corresponding transmit antenna ports on the frequency domain positions being a combination of frequency domain positions corresponding to a first index in an arrangement matrix and transmit antenna ports, that is, the reference signals received by the first device may be some of reference signals (for example, only some of receive antenna ports and some of frequency domain positions are occupied), thereby facilitating the reduction of the pilot overhead of sending the reference signals. The first device sends a first channel matrix or a second channel matrix, that is, compared with a precoding matrix indicator feedback method, less information is fed back (for example, only one channel matrix needs to be fed back) by using the method in which the first channel matrix or the second channel matrix is fed back by the first device, so that the feedback overhead of the reference signals can be reduced.

Description

Communication method and communication device Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a communication method and a communication device. Background Art

[0002] The fifth generation of new wireless th In the new generation radio (5GNR) communication technology, the channel state information reference signal (CSI-RS) supports multiple antenna ports occupying multiple resource elements (RE) resources. For example, using the current 5G NR CSI-RS pattern, the pilot resources used to send the reference signal will be proportional to the number of antenna ports (such as the current maximum number of ports supported by 5G is 32, and the number of communication antenna ports in the future may be expanded to 1024 or more), resulting in a significant increase in the CSI-RS pilot overhead. In addition, the current 5G NR uses the precoding matrix indicator (PMI) feedback method. Since the calculation of PMI requires singular value decomposition (SVD) of the matrix according to the antenna port dimension, in future large-scale antenna scenarios, the CSI-RS feedback overhead (including the complexity of the calculation and the number of codebooks for PMI feedback) will also increase sharply.

[0003] Summary of the Invention

[0004] The present application provides a communication method and a communication device, which can reduce the feedback overhead of a reference signal.

[0005] In a first aspect, the present application provides a communication method, which is performed by a first device. The first device may be a terminal, a component of a terminal (such as a processor, a chip, or a chip system), or a logic module that can implement all or part of the terminal functions. The first device receives a reference signal, and the frequency domain position of the reference signal and the corresponding transmit antenna port at the frequency domain position are a combination of the frequency domain position and the transmit antenna port corresponding to the first index in the permutation matrix; the permutation matrix is ​​obtained according to a first projection matrix and a first decomposition method, and the first projection matrix is ​​obtained according to a training matrix and a second decomposition method. The first device sends a first channel matrix or a second channel matrix, the first channel matrix is ​​determined according to a combination of the frequency domain position and the transmit antenna port corresponding to the first index in the permutation matrix and the receive antenna port, the second channel matrix is ​​determined according to the first channel matrix and the second projection matrix, and the second projection matrix is ​​determined according to the permutation matrix and the first projection matrix or indicated by the second device.

[0006] In this method, the reference signal received by the first device occupies only a portion of the frequency domain positions and transmit antenna ports across all transmit antenna ports and all frequency domain positions, and the arrangement of the occupied frequency domain positions and transmit antenna ports within the space formed by all transmit antenna ports and all frequency domain positions is non-uniform, thereby facilitating the reduction of pilot overhead for transmitting the reference signal. Furthermore, the first channel matrix or second channel matrix fed back by the first device provides less feedback information (e.g., only one channel matrix needs to be fed back) compared to a feedback method indicated by a precoding matrix, thereby reducing the reference signal feedback overhead.

[0007] In one possible implementation, the first device performs channel estimation based on a reference signal to determine a first channel matrix. The first device receives a second projection matrix, or obtains the second projection matrix through training based on a training matrix and the first projection matrix. The first device determines a second channel matrix based on the first channel matrix and the second projection matrix.

[0008] In this method, the first device can directly and explicitly feed back the first channel matrix; or, the first device can determine the second channel matrix based on the first channel matrix and the second projection matrix, thereby implicitly feeding back the second channel matrix (implicitly means that after the second device receives the second channel matrix, it needs to convert the second channel matrix into the first channel matrix, thereby reconstructing the channel). Regardless of explicit or implicit feedback, the feedback overhead of the reference signal can be reduced.

[0009] In one possible implementation, the first channel matrix includes channel matrices on one or more groups of receiving antenna ports corresponding to the combination of the frequency domain position of the reference signal and the transmitting antenna port; the second channel matrix can be obtained by multiplying the first channel matrix by the inverse matrix of the second projection matrix.

[0010] In this method, since the frequency domain position of the reference signal and the transmit antenna port have a one-to-one correspondence, the first channel matrix fed back by the first device includes the channel matrices for one or more groups of receive antenna ports corresponding to the combination of the frequency domain position of the reference signal and the transmit antenna port. For example, the receive antenna ports corresponding to the combination of any set of reference signal frequency domain positions and transmit antenna ports include the i-th frequency domain position and the j-th receive antenna port, where the i-th frequency domain position corresponds to the k-th transmit antenna port. If i, j, and k are positive integers, the first channel matrix includes the channel matrices for the i-th frequency domain position, the k-th transmit antenna port, and the j-th receive antenna port. The second channel matrix includes coefficients corresponding to the first channel matrix, where the coefficients are mathematical values.

[0011] In one possible implementation, the number of elements in the first channel matrix or the number of elements in the second channel matrix is ​​r; wherein r is the number of combinations of frequency domain positions and transmit antenna ports corresponding to the first index in the permutation matrix.

[0012] In one possible implementation, the first device receives second information, where the second information is used to indicate an index of a receiving antenna port for which feedback is required. The first channel matrix includes a channel matrix on the receiving antenna port for which feedback is required, corresponding to a combination of a frequency domain position of a reference signal and a transmitting antenna port.

[0013] In the above method, the first channel matrix or the second channel matrix includes a combination of one or more groups of receive antenna ports at the frequency domain position of the reference signal. That is, the first channel matrix or the second channel matrix only carries the combination information of the receive antenna ports and the frequency domain position, which can further reduce the feedback overhead of the reference signal (only some combinations of receive antenna ports and frequency domain positions are fed back, and fewer channel matrices are fed back). However, the base station needs to additionally indicate to the terminal the index of the receive antenna port that requires feedback (such as using a small portion of air interface resources to indicate the index of the receive antenna port).

[0014] In one possible implementation, the first channel matrix includes channel matrices on some or all receive antenna ports corresponding to the combination of the reference signal's frequency domain position and the transmit antenna port. For example, the reference signal's frequency domain position and the transmit antenna port's combination corresponding to some or all receive antenna ports include: for any frequency domain position (assuming it is the i-th frequency domain position), all receive antenna ports corresponding to the combination of the i-th frequency domain position and the j-th receive antenna port include the combination of the i-th frequency domain position, the k-th transmit antenna port, and the first receive antenna port, up to the i-th frequency domain position, the k-th transmit antenna port and the n-th receive antenna port; n is a positive integer. The second channel matrix includes coefficients corresponding to the first channel matrix, where the coefficients are mathematical values.

[0015] In one possible implementation, the number of elements of the first channel matrix or the number of elements of the second channel matrix is ​​r*n; where r is the number of combinations of frequency domain positions and transmitting antenna ports corresponding to the first index in the permutation matrix, and n is the number of some or all receiving antenna ports.

[0016] In the above method, the first channel matrix or the second channel matrix includes some or all combinations of receive antenna ports at the frequency domain location where the reference signal is transmitted. Compared to the feedback method indicated by the precoding matrix, the reference signal feedback overhead is significantly reduced. Although more channel matrices require feedback (for example, some or all combinations of receive antenna ports at the frequency domain location where the reference signal is transmitted), the base station does not need to additionally indicate to the terminal the indices of the receive antenna ports for which feedback is required.

[0017] In a possible implementation, the first device receives third information, where the third information includes the second projection matrix; or, the third information is used to indicate the second projection matrix.

[0018] In the above method, the first device can receive the second projection matrix; or when the terminal already knows the first projection matrix, it receives third information indicating the second projection matrix (assuming that the third information includes a permutation matrix), and the terminal can determine the second projection matrix based on the first projection matrix and the permutation matrix; or, when the terminal already knows the dimensions of the first projection matrix and the permutation matrix, it receives the first index in the permutation matrix (for example, the first index in the permutation matrix indicates the position of the reference signal).

[0019] In one possible implementation, the first device uses a single sequence to perform channel estimation on reference signals at different frequency domain positions; or uses multiple filters to perform channel estimation on reference signals at different frequency domain positions; or uses a spatial domain filter to perform channel estimation on reference signals at the same frequency domain position.

[0020] In this method, the first device may perform channel estimation on the reference signal in different ways, thereby obtaining the first channel matrix or the second channel matrix.

[0021] In a possible implementation, the first apparatus receives fourth information, where the fourth information is used to instruct the terminal device to feed back the first channel matrix or the second channel matrix.

[0022] In this method, the first device may receive a configuration for reference signal feedback, such as instructing the first device to provide feedback in an explicit or implicit manner, instructing the first device to provide feedback in the first channel matrix or the second channel matrix, and the like.

[0023] In a second aspect, the present application provides a communication method, which is performed by a second device. The second device may be a network device, a component of a network device (such as a processor, a chip, or a chip system, etc.), or a logic module that can implement all or part of the network device functions. The second device sends a reference signal, and the frequency domain position of the reference signal and the corresponding transmit antenna port at the frequency domain position are a combination of the frequency domain position and the transmit antenna port corresponding to the first index in the permutation matrix; the permutation matrix is ​​obtained according to the first projection matrix and the first decomposition method, and the first projection matrix is ​​obtained according to the training matrix and the second decomposition method. The second device receives a first channel matrix or a second channel matrix, the first channel matrix is ​​determined according to the combination of the frequency domain position and the transmit antenna port corresponding to the first index in the permutation matrix and the receive antenna port, the second channel matrix is ​​determined according to the first channel matrix and the second projection matrix, and the second projection matrix is ​​determined according to the permutation matrix and the first projection matrix or indicated by the second device.

[0024] In this method, the second device can send a partial reference signal to the first device (e.g., the partial reference signal occupies only a portion of the frequency domain positions and transmit antenna ports among all transmit antenna ports and all frequency domain positions, and the arrangement of the occupied partial frequency domain positions and transmit antenna ports in the space formed by all transmit antenna ports and all frequency domain positions is non-uniform), which can reduce the pilot overhead of sending the reference signal. Furthermore, when the second device receives the first channel matrix or the second channel matrix fed back by the first device, the feedback information is less than that indicated by the precoding matrix (e.g., only one channel matrix needs to be fed back), which is beneficial for reducing the feedback overhead of the reference signal.

[0025] In one possible implementation, the second device combines channel matrices of multiple time units into a training matrix and decomposes the training matrix using a second decomposition method to obtain an intermediate matrix and a decomposition rank. The second device selects a column corresponding to the decomposition rank from the intermediate matrix to obtain a first projection matrix. The second device decomposes the first projection matrix using the first decomposition method to obtain a permutation matrix.

[0026] In this method, the second device can determine the permutation matrix through pre-training and combining the first decomposition method (such as orthogonal triangular QR decomposition or machine learning), the second decomposition method (such as singular value decomposition SVD or machine learning) and other operations. The frequency domain position corresponding to the first index of the permutation matrix and the combination of the corresponding transmitting antenna port at the frequency domain position are the combination of the frequency domain position and the transmitting antenna port of the reference signal, which is beneficial to reducing the pilot overhead of sending the reference signal.

[0027] In one possible implementation, the first channel matrix includes channel matrices on one or more groups of receiving antenna ports corresponding to the combination of the frequency domain position of the reference signal and the transmitting antenna port; the second channel matrix is ​​obtained by multiplying the first channel matrix by the inverse matrix of the second projection matrix.

[0028] In this method, when the receiving end provides feedback to the transmitting end, since there is a one-to-one correspondence between frequency domain positions and transmit antenna ports, the first channel matrix includes channel matrices for one or more groups of receive antenna ports corresponding to the combination of the reference signal's frequency domain position and transmit antenna port. For example, the receive antenna ports corresponding to any combination of the reference signal's frequency domain position and transmit antenna port include the i-th frequency domain position and the j-th receive antenna port, where the i-th frequency domain position corresponds one-to-one to the k-th transmit antenna port; i, j, and k are positive integers, and the first channel matrix includes channel matrices for the i-th frequency domain position, the k-th transmit antenna port, and the j-th receive antenna port. The second channel matrix includes coefficients corresponding to the first channel matrix, where the coefficients are mathematical values.

[0029] In one possible implementation, the number of elements in the first channel matrix or the number of elements in the second channel matrix is ​​r; wherein r is the number of combinations of frequency domain positions and transmit antenna ports corresponding to the first index in the permutation matrix.

[0030] In a possible implementation manner, the second device sends second information, where the second information is used to indicate an index of a receiving antenna port requiring feedback.

[0031] In an embodiment in which the second device receives the first channel matrix, the second device receives the channel matrix on the receiving antenna port requiring feedback corresponding to a combination of the frequency domain position of the reference signal and the transmitting antenna port.

[0032] In the above method, the first channel matrix or the second channel matrix includes one or more combinations of receive antenna ports and frequency domain positions. That is, the first channel matrix or the second channel matrix only carries information about some receive antenna ports corresponding to the combination of the reference signal's frequency domain position and transmit antenna port. This can further reduce the reference signal feedback overhead (fewer channel matrices are fed back). However, the base station needs to additionally indicate to the terminal the index of the receive antenna port for which feedback is required (e.g., using a small portion of air interface resources to indicate the index of the receive antenna port).

[0033] In one possible implementation, the first channel matrix includes channel matrices on some or all receive antenna ports corresponding to the combination of the reference signal's frequency domain position and the transmit antenna port. For example, the some or all receive antenna ports corresponding to the combination of the reference signal's frequency domain position and the transmit antenna port include: for any frequency domain position (assuming it is the i-th frequency domain position), the some or all receive antenna ports corresponding to the combination of the i-th frequency domain position and the j-th receive antenna port include the combination of the i-th frequency domain position, the k-th transmit antenna port and the 1st receive antenna port, up to the i-th frequency domain position, the k-th transmit antenna port and the n-th receive antenna port; n is a positive integer. The second channel matrix includes coefficients corresponding to the first channel matrix, where the coefficients are mathematical values.

[0034] In one possible implementation, the number of elements of the first channel matrix or the number of elements of the second channel matrix is ​​r*n; where r is the number of combinations of frequency domain positions and transmitting antenna ports corresponding to the first index in the permutation matrix, and n is the number of some or all receiving antenna ports.

[0035] In the above method, the first channel matrix or the second channel matrix includes some or all combinations of receive antenna ports at the frequency domain location where the reference signal is transmitted. Compared to the feedback method indicated by the precoding matrix, the reference signal feedback overhead is significantly reduced. Although more channel matrices require feedback (including some or all combinations of receive antenna ports at the frequency domain location where the reference signal is transmitted), the base station does not need to additionally indicate to the terminal the indices of the receive antenna ports for which feedback is required.

[0036] In a possible implementation, the second device sends third information, where the third information includes the second projection matrix; or, the third information is used to indicate the second projection matrix.

[0037] In the above method, the second device can send the second projection matrix to the first device; or when the terminal already knows the first projection matrix, send third information for indicating the second projection matrix (assuming that the third information includes a permutation matrix), which is beneficial for the terminal to determine the second projection matrix based on the first projection matrix and the permutation matrix; or, when the terminal already knows the dimensions of the first projection matrix and the permutation matrix, send the first index in the permutation matrix (for example, the first index in the permutation matrix indicates the position of the reference signal).

[0038] In a possible implementation, the second device determines a resource pattern of the reference signal based on a channel matrix of multiple time units; and maps ports in the resource pattern to resource units in the time domain and / or frequency domain based on the resource pattern.

[0039] In the method, the second device may train the pattern of the reference signal and configure the pattern of the reference signal so that the second device may determine the position of the reference signal according to the pattern of the reference signal.

[0040] In a possible implementation, the second device maps n transmit antenna ports to the same code division multiplexing group; the configuration of the n transmit antenna ports is for each terminal device and is dynamically configurable.

[0041] In this method, the second device can dynamically / configurably map the ports of the reference signal to the code division multiplexing groups, thereby achieving flexible code division multiplexing configuration.

[0042] In a possible implementation, the second device sends fourth information, where the fourth information is used to instruct the terminal device to feed back the first channel matrix or the second channel matrix.

[0043] In this method, the second device may design a configuration for reference signal feedback, such as instructing the first device to provide feedback in an explicit or implicit manner, instructing the first device to provide feedback in the first channel matrix or the second channel matrix, etc.

[0044] In a third aspect, the present application provides a communication device, which may be a terminal, a device for a terminal, or a device capable of being used in conjunction with a terminal. In one possible implementation, the communication device may include a functional module, which may be implemented as a hardware circuit, software, or a combination of hardware circuits and software.

[0045] In one possible embodiment, the communication device includes a communication unit. The communication unit is used to receive a reference signal, wherein the frequency domain position of the reference signal and the corresponding transmitting antenna port at the frequency domain position are a combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix; the permutation matrix is ​​obtained based on the first projection matrix and the first decomposition method, and the first projection matrix is ​​obtained based on the training matrix and the second decomposition method. The communication unit is also used to send a first channel matrix or a second channel matrix, wherein the first channel matrix is ​​determined based on the combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix and the receiving antenna port, and the second channel matrix is ​​determined based on the first channel matrix and the second projection matrix, and the second projection matrix is ​​determined based on the permutation matrix and the first projection matrix or indicated by the second device.

[0046] In one possible implementation, the communication device further includes a processing unit. The processing unit is configured to perform channel estimation based on the reference signal to determine a first channel matrix. The communication unit is configured to receive a second projection matrix, or the processing unit is configured to train the second projection matrix based on the training matrix and the first projection matrix. The processing unit is configured to determine a second channel matrix based on the first channel matrix and the second projection matrix.

[0047] In one possible implementation, the first channel matrix includes channel matrices on one or more groups of receiving antenna ports corresponding to the combination of the frequency domain position of the reference signal and the transmitting antenna port; the second channel matrix is ​​obtained by multiplying the first channel matrix by the inverse matrix of the second projection matrix.

[0048] In one possible implementation, the number of elements in the first channel matrix or the number of elements in the second channel matrix is ​​r; wherein r is the number of combinations of frequency domain positions and transmit antenna ports corresponding to the first index in the permutation matrix.

[0049] In a possible implementation, the communication unit is configured to receive second information, where the second information is used to indicate an index of a receiving antenna port requiring feedback.

[0050] In a possible implementation manner, the communication unit is configured to send a channel matrix on the receiving antenna port requiring feedback corresponding to a combination of a frequency domain position of the reference signal and a transmitting antenna port.

[0051] In a possible implementation, the first channel matrix includes channel matrices on some or all of the receiving antenna ports corresponding to a combination of a frequency domain position of the reference signal and a transmitting antenna port.

[0052] In one possible implementation, the number of elements of the first channel matrix or the number of elements of the second channel matrix is ​​r*n; where r is the number of combinations of frequency domain positions and transmitting antenna ports corresponding to the first index in the permutation matrix, and n is the number of some or all receiving antenna ports.

[0053] In a possible implementation, the communication unit is configured to receive third information, where the third information includes the second projection matrix; or, the third information is configured to indicate the second projection matrix.

[0054] In one possible implementation, the processing unit is used to: use a single sequence to perform channel estimation on reference signals at different frequency domain positions; or use multiple filters to perform channel estimation on reference signals at different frequency domain positions; or use a spatial domain filter to perform channel estimation on reference signals at the same frequency domain position.

[0055] In a possible implementation, the communication unit is configured to receive fourth information, where the fourth information is used to instruct the terminal device to feed back the first channel matrix or the second channel matrix.

[0056] In a fourth aspect, the present application provides a communication device, which may be a network device, a device of a network device, or a device capable of being used in conjunction with a network device. In one possible implementation, the communication device may include a functional module, which may be implemented as a hardware circuit, software, or a combination of hardware circuit and software.

[0057] In one possible embodiment, the communication device includes a communication unit. The communication unit is used to send a reference signal, and the frequency domain position of the reference signal and the corresponding transmit antenna port at the frequency domain position are a combination of the frequency domain position and the transmit antenna port corresponding to the first index in the permutation matrix; the permutation matrix is ​​obtained based on the first projection matrix and the first decomposition method, and the first projection matrix is ​​obtained based on the training matrix and the second decomposition method. The communication unit is also used to receive a first channel matrix or a second channel matrix, the first channel matrix is ​​determined based on the combination of the frequency domain position and the transmit antenna port corresponding to the first index in the permutation matrix and the receive antenna port, the second channel matrix is ​​determined based on the first channel matrix and the second projection matrix, and the second projection matrix is ​​determined based on the permutation matrix and the first projection matrix or indicated by the second device.

[0058] In one possible implementation, the communication device further includes a processing unit. The processing unit is configured to combine channel matrices of multiple time units into a training matrix. The processing unit is further configured to decompose the training matrix using a second decomposition method to obtain an intermediate matrix and a decomposition rank. The processing unit is further configured to select a column corresponding to the decomposition rank from the intermediate matrix to obtain a first projection matrix. The processing unit is further configured to decompose the first projection matrix using the first decomposition method to obtain a permutation matrix.

[0059] In one possible implementation, the first channel matrix includes channel matrices on one or more groups of receiving antenna ports corresponding to the combination of the frequency domain position of the reference signal and the transmitting antenna port; the second channel matrix is ​​obtained by multiplying the first channel matrix by the inverse matrix of the second projection matrix.

[0060] In one possible implementation, the number of elements in the first channel matrix or the number of elements in the second channel matrix is ​​r; wherein r is the number of combinations of frequency domain positions and transmit antenna ports corresponding to the first index in the permutation matrix.

[0061] In a possible implementation, the communication unit is configured to send second information, where the second information is used to indicate an index of a receiving antenna port requiring feedback.

[0062] In a possible implementation, the communication unit is configured to receive a channel matrix on the receiving antenna port requiring feedback corresponding to a combination of a frequency domain position of the reference signal and a transmitting antenna port.

[0063] In one possible implementation, the first channel matrix includes channel matrices on some or all receive antenna ports corresponding to the combination of the reference signal's frequency domain position and the transmit antenna port. For example, all receive antenna ports corresponding to the combination of the reference signal's frequency domain position and the transmit antenna port include: for any frequency domain position (assuming it is the i-th frequency domain position), all receive antenna ports corresponding to the combination of the i-th frequency domain position and the j-th receive antenna port include the combination of the i-th frequency domain position, the k-th transmit antenna port, and the first receive antenna port, up to the i-th frequency domain position, the k-th transmit antenna port and the n-th receive antenna port; n is a positive integer. The second channel matrix includes coefficients corresponding to the first channel matrix, where the coefficients are mathematical values.

[0064] In one possible implementation, the number of elements of the first channel matrix or the number of elements of the second channel matrix is ​​r*n; where r is the number of combinations of frequency domain positions and transmitting antenna ports corresponding to the first index in the permutation matrix, and n is the number of some or all receiving antenna ports.

[0065] In a possible implementation, the communication unit is configured to send third information, where the third information includes the second projection matrix; or, the third information is configured to indicate the second projection matrix.

[0066] In one possible implementation, the processing unit is configured to determine a resource pattern of a reference signal based on a channel matrix of multiple time units and to map ports in the resource pattern to resource units in the time domain and / or frequency domain based on the resource pattern.

[0067] In a possible implementation, the processing unit is configured to map n transmit antenna ports to a same code division multiplexing group; the configuration of the n transmit antenna ports is specific to each terminal device and is dynamically configurable.

[0068] In a possible implementation, the communication unit is configured to send fourth information, where the fourth information is used to instruct the terminal device to feed back the first channel matrix or the second channel matrix.

[0069] With respect to the third aspect or the fourth aspect, as an example, the processing unit may be a processor, and the communication unit may be a transceiver unit, a transceiver, or a communication interface. It is understood that when the communication device is a communication device (e.g., a terminal or a network device), the communication unit may be a transceiver in the communication device (e.g., a transceiver includes a transmitter and a receiver), such as implemented by an antenna, a feeder, and a codec in the communication device, or, if the communication device is a chip provided in the device, the processing unit may be a processing circuit, a logic circuit, etc. of the chip, and the communication unit may be an input / output interface of the chip, such as an input / output circuit, a pin, etc.

[0070] In a fifth aspect, the present application provides a communication device, comprising: a processor configured to execute instructions; optionally, the communication device further comprising a memory configured to store the instructions, wherein when the instructions are executed by the processor, the communication device implements the method of the first aspect and any possible implementation of the first aspect. Optionally, the processor and the memory are coupled.

[0071] In a sixth aspect, the present application provides another communication device, comprising: a processor configured to execute instructions; optionally, the communication device further comprising a memory configured to store the instructions, wherein when the instructions are executed by the processor, the communication device implements the method of the second aspect and any possible implementation of the second aspect. Optionally, the processor and the memory are coupled.

[0072] In the seventh aspect, the present application provides a communication system, which includes multiple devices or equipment in the above-mentioned third to sixth aspects, so that the devices or equipment execute the methods in the first and second aspects, as well as any possible implementation of the first and second aspects.

[0073] In an eighth aspect, the present application provides a computer-readable storage medium storing instructions, which, when the instructions are executed on a computer, enable the computer to execute the method of the first aspect and the second aspect, as well as any possible implementation of the first aspect and the second aspect.

[0074] In a ninth aspect, the present application provides a chip system comprising a processor and an interface, and optionally, a memory, for implementing the method of the first and second aspects, as well as any possible implementation of the first and second aspects. The chip system may be composed of a chip, or may include a chip and other discrete devices.

[0075] In a tenth aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, enable the computer to execute the method of the first aspect and the second aspect, as well as any possible implementation of the first aspect and the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] FIG1 is a schematic diagram of a communication system provided by the present application;

[0077] FIG2 is a schematic diagram of a process of performing CSI measurement and feedback by a base station and a terminal;

[0078] FIG3 is a flow chart of a communication method provided by the present application;

[0079] FIG4 is a schematic diagram of a training process of a permutation matrix provided in this application;

[0080] FIG5 is a schematic diagram of a dynamic CDM group provided by the present application;

[0081] FIG6 is a schematic diagram of the relationship between a channel matrix of a transmitting antenna port, a receiving antenna port, and a frequency domain position and a first channel matrix provided by the present application;

[0082] FIG7 is a schematic diagram showing the relationship between the first channel matrix and the second channel matrix provided by the present application;

[0083] FIG8 is a schematic diagram showing the relationship between another channel matrix of transmitting antenna ports, receiving antenna ports, and frequency domain positions and the first channel matrix provided by the present application;

[0084] FIG9 is a schematic diagram of a process of performing channel estimation based on a reference signal, obtaining and sending a first channel matrix according to a first apparatus provided by the present application;

[0085] FIG10 is a schematic diagram of a process of performing channel estimation based on a reference signal to obtain and send a first channel matrix in another first apparatus provided by the present application;

[0086] FIG11 is a schematic diagram of performing CDM to increase transmit power under a CSI-RS port provided by the present application;

[0087] FIG12 is a schematic diagram of a simulation of reference signal patterns trained using different time units provided by the present application;

[0088] FIG13 is a schematic diagram of a simulation of the average downlink rate after channel estimation using a reference signal obtained by training for 100 time units under different signal-to-noise ratios according to the communication method provided by the present application;

[0089] FIG14 is a schematic diagram of a communication device provided by the present application;

[0090] FIG15 is a schematic diagram of another communication device provided in this application. DETAILED DESCRIPTION

[0091] In the embodiments of this application, " / " can indicate that the associated objects are in an "or" relationship. For example, A / B can mean A or B. "And / or" can be used to describe the existence of three relationships between associated objects. For example, "A and / or B" can mean: A exists alone, A and B exists simultaneously, or B exists alone. A and B can be singular or plural. To facilitate the description of the technical solutions of the embodiments of this application, the words "first" and "second" may be used in the embodiments of this application to distinguish between technical features with the same or similar functions. The words "first" and "second" do not limit the number or order of execution, and the words "first" and "second" do not necessarily mean different. In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary" or "for example" should not be construed as preferred or advantageous over other embodiments or designs. The use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner for easier understanding.

[0092] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0093] In order to reduce the feedback overhead of reference signals, the present application provides a communication method, which can significantly reduce the feedback overhead of reference signals under large-scale antennas.

[0094] The communication method provided in this application can be applied to the communication system shown in Figure 1. For example, the communication system includes a network device and a terminal.

[0095] Among them, the communication system of the present application may include but is not limited to communication systems of various radio access technologies (RAT), for example, it may be: a narrowband Internet of Things system (NB-IoT), a long term evolution (LTE) communication system, or a 5G (or new radio (NR)) communication system, or a transition system between an LTE communication system and a 5G communication system, which may also be called a 4.5G communication system, and of course it may also be a future communication system, such as the sixth generation (6G) or even the seventh generation (7G) system. The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. It is known to those skilled in the art that with the evolution of the communication network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0096] Among them, a terminal, also known as a terminal device (terminal), user equipment (UE), mobile station (MS), mobile terminal (MT), etc., refers to a device that provides voice and / or data connectivity to users. For example, a handheld device with wireless connection function, a vehicle-mounted device, etc. Currently, some examples of terminals include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, drones, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control (industrial control), wireless terminals in self-driving (self-driving), wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety (transportation safety), wireless terminals in smart cities (smart cities), wireless terminals in smart homes (smart homes), terminals in 5G networks, terminals in future evolved networks, or terminals in future communication systems.

[0097] The network device of the present application refers to a radio access network (RAN) node (or device) that connects a terminal to a wireless network, and may also be referred to as a base station. For example, some examples of RAN nodes include: a gNB, a transmission reception point (TRP), an evolved Node B (eNB), a radio network controller (RNC), a Node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., a home evolved NodeB, or a home Node B, HNB), a base band unit (BBU), or a wireless fidelity (Wifi) access point (AP), a satellite in a satellite communication system, a radio controller in a cloud radio access network (CRAN) scenario, a wearable device, a drone, or a device in an Internet of Vehicles (e.g., vehicle to everything (V2X)), or a communication device in device to device (D2D) communication. In addition, in a network structure, the network device may include a centralized unit (CU) node, a distributed unit (DU) node, or a RAN device including a CU node and a DU node. The RAN device including the CU node and the DU node splits the protocol layer of the eNB in ​​the long term evolution (LTE) system, places the functions of some protocol layers under central control in the CU, and distributes the functions of the remaining part or all of the protocol layers in the DU, which is centrally controlled by the CU. In some deployments of network devices, the CU can also be divided into a CU-control plane (CP) and a CU-user plane (UP), etc. In other deployments of network devices, the network device can also be an antenna unit (RU), etc. In some other deployments of network devices, the network device can also be an open radio access network (ORAN) architecture, etc. This application does not limit the specific type of network device.For example, when the network device is an ORAN architecture, the network device shown in the embodiment of the present application may be an access network device in the ORAN, or a module in the access network device. In the ORAN system, the CU may also be referred to as an open centralized unit (open CU, O-CU), the DU may also be referred to as an open distributed unit (O-DU), the CU-DU may also be referred to as an open centralized unit-distributed unit (O-CU-DU), the CU-UP may also be referred to as an open centralized unit-control plane (O-CU-UP), and the RU may also be referred to as an open antenna unit (O-RU).

[0098] It should be noted that:

[0099] "Sending" and "receiving" in the embodiments of the present application indicate the direction of signal transmission. For example, "sending information to a terminal" can be understood as the destination end of the information being the terminal device, which can include direct sending through the air interface, and also includes indirect sending through the air interface by other units or modules. "Receiving information from a network device" can be understood as the source end of the information being the network device, which can include direct receiving from the network device through the air interface, and also includes indirect receiving from the network device through the air interface from other units or modules. "Sending" can also be understood as the "output" of the chip interface, and "receiving" can also be understood as the "input" of the chip interface.

[0100] In other words, sending and receiving can be performed between devices, for example, between a network device and a terminal device, or can be performed within a device, for example, sending or receiving between components, modules, chips, software modules or hardware modules within the device through a bus, wiring or interface.

[0101] It is understandable that information may be processed between the source and destination of information transmission, such as coding, modulation, etc., but the destination can understand the valid information from the source. Similar expressions in this application can be understood similarly and will not be repeated.

[0102] In the embodiments of the present application, "indication" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. The information indicated by a certain information (such as the indication information described below) is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, wherein there is an association between the other information and the information to be indicated; it is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance, for example, the indication of specific information can be achieved with the help of the arrangement order of each information agreed in advance (such as predefined by the protocol), thereby reducing the indication overhead to a certain extent. The present application does not limit the specific method of indication. It is understandable that, for the sender of the indication information, the indication information can be used to indicate the information to be indicated, and for the receiver of the indication information, the indication information can be used to determine the information to be indicated.

[0103] 1. To facilitate understanding, the definitions of relevant terms involved in this application are introduced in detail below.

[0104] 1. Channel State Information Reference Signaling (CSI-RS):

[0105] (1) CSI-RS configuration:

[0106] In 5G communication systems, massive multiple input multiple output (Massive MIMO) technology plays a vital role in the spectrum efficiency of the system. When using MIMO technology, modulation coding and signal precoding are required when the base station sends data to the UE. How to send data to the user depends on the channel state information (CSI) fed back by the user to the base station. In one possible implementation, CSI-RS includes two types: zero power channel state information reference signal (ZP CSI-RS) and non-zero power channel state information reference signal (non ZP CSI-RS, NZP CSI-RS). Among them, NZP CSI-RS is mainly used to obtain channel status (such as time-frequency domain tracking, beam training, CSI channel feedback, etc.), and ZP CSI-RS is mainly used for rate matching.

[0107] In one possible implementation, FIG2 is a schematic diagram of a process of performing CSI measurement and feedback by a base station and a UE, including the following steps:

[0108] Step 1: The base station sends channel measurement configuration information. For example, the base station needs to first send signaling for channel measurement configuration to inform the UE of the time and behavior of channel measurement.

[0109] Step 2: The base station sends a channel measurement reference signal (also called a pilot). For example, the base station sends a pilot to the UE for channel measurement. In NR, the network side can send a reference signal (such as NZP CSI-RS) to detect the downlink channel, and the UE receives the NZP CSI-RS signal on the pre-configured channel measurement resource (CMR) for channel estimation. In addition, the network side will further configure a set of interference measurement resources (IMR) corresponding to the CMR for the UE. The UE receives signals on these pre-configured IMRs and performs interference measurement.

[0110] Step 3: The terminal performs channel measurement based on the pilot, obtains the pilot measurement result and feeds back the CSI to the base station.

[0111] For example, the UE receives signals on a pre-configured IMR and performs CSI interference measurement (CSI-IM). The UE calculates the final CSI feedback based on the measurement results on the CMR and IMR.

[0112] Step 4: The base station sends data based on the CSI fed back by the terminal.

[0113] For example, the base station determines the number of data streams to be transmitted to the UE based on the channel rank indicator (RI) fed back by the UE; the base station determines the modulation order and channel coding code rate of the data to be transmitted to the UE based on the channel quality indicator (CQI) fed back by the UE; and the base station determines the precoding of the data to be transmitted to the UE based on the precoding matrix indicator (PMI) fed back by the UE.

[0114] (2) CSI measurement:

[0115] The NZP CSI-RS resources for CMR and the CSI-IM resources for IMR can be periodic, semi-persistent, or aperiodic. Specifically, the periodic / semi-persistent / aperiodic NZP CSI-RS resources and CSI-IM resources are configured to the UE through high-layer signaling (such as radio resource control (RRC) signaling). For example, for periodic NZP CSI-RS / CSI-IM resources, the UE receives NZP CSI-RS signals on periodic NZP CSI-RS resources with fixed intervals or measures interference on periodic CSI-IM resources with fixed intervals, where the period of the NZP CSI-RS resources can be configured through high-layer signaling (such as RRC signaling). For another example, for semi-persistent NZP CSI-RS / CSI-IM resources, the network side can activate and deactivate through signaling. During the activation period, the UE receives NZP CSI-RS signals on periodic NZP CSI-RS resources with fixed intervals or measures interference on periodic CSI-IM resources with fixed intervals, where the period of the NZP CSI-RS resources can be configured through high-layer signaling (such as RRC signaling). For another example, for non-periodic NZP CSI-RS / CSI-IM resources, the network side can configure an NZP CSI-RS resource set (NZP-CSI-RS-ResourceSet) for the UE through high-layer signaling, where each NZP CSI-RS resource set contains multiple NZP CSI-RS resources, and each NZP CSI-RS resource set is configured with a slot offset (slot offset) for determining the time slot in which the NZP CSI-RS resource in the set is located.

[0116] (3) CSI reporting:

[0117] CSI reporting can be periodic, semi-persistent, or aperiodic, similar to CSI measurement.

[0118] For example, in periodic CSI reporting (P-CSI), the base station configures the UE to perform periodic CSI reporting through higher-layer signaling. The UE performs channel and interference measurements based on the periodic CSI-RS resources and reports CSI feedback at fixed intervals. In periodic CSI reporting, the CMR and IMR used for CSI measurement are both periodic.

[0119] For another example, in semi-persistent CSI reporting (SP-CSI), the UE is configured to perform semi-persistent CSI reporting. That is, the UE starts CSI reporting after receiving the downlink activation signaling sent by the base station, and ends CSI reporting after receiving the downlink deactivation signaling. Between these two downlink signaling moments, the UE performs periodic CSI measurement and reporting. Among them, the CMR and IMR used for semi-persistent CSI reporting can be periodic or semi-persistent. Optionally, semi-persistent CSI reporting can be reported on the physical uplink control channel (PUCCH) resources, and the base station activates and deactivates semi-persistent CSI reporting through downlink high-layer signaling (such as MAC (medium access control, media access control) control element (MAC control element, MAC CE) signaling). Semi-persistent CSI reporting can also be performed on physical uplink shared channel (PUSCH) resources. The base station activates and deactivates semi-persistent CSI reporting through physical layer downlink control information (DCI).

[0120] For another example, in aperiodic CSI reporting (AP-CSI), the base station first semi-statically configures multiple CSI reporting configuration parameters for the UE through downlink RRC signaling, triggers one or more CSI reporting through downlink control information DCI, and the UE performs CSI measurement according to the CSI reporting configuration parameters and uses PUSCH to report the CSI measurement results. Among them, although aperiodic CSI measurement and / or reporting, like semi-persistent CSI measurement and / or reporting, requires base station triggering, aperiodic CSI measurement and / or reporting does not need to be deactivated after DCI triggering, and only one measurement and / or reporting is performed. The CMR and IMR used for aperiodic CSI reporting can be periodic, semi-persistent, or aperiodic.

[0121] In one possible implementation, the content reported in the CSI Report (such as quantity measurement), also known as CSI measurement channel parameters, includes but is not limited to the following: CSI-RS resource indicator (CRI), rank indicator (RI), PMI, CQI, layer index (LI), etc. Among them, CRI is used to indicate the best CSI-RS resource index, corresponding to the best beam. RI is used to indicate the number of transmission layers (based on CRI). When a single codeword is used, the number of RIs is 1-4; when a dual codeword is used, the number of RIs is 1-8. PMI indicates the PMI recommended by the UE based on RI. CQI indicates the appropriate coding and modulation method obtained based on PMI and feedback is provided for each codeword. The value range of CQI is 1-15. Each CQI corresponds to a modulation method and code rate, such as supporting 64QAM and 256QAM. LI is a new concept introduced by NR. LI is used to indicate a column of the precoding matrix corresponding to the reported PMI. This column corresponds to the strongest layer of the codeword with a larger wideband CQI. LI only requires 2 bits to represent.

[0122] (4) Analysis of PMI estimation computational complexity:

[0123] Among them, channel estimation and singular value decomposition (SVD) or eigenvalue decomposition (EVD) in the PMI estimation operation based on Type II codebook are the key to determining the complexity of PMI estimation operation. Specifically, the complexity of PMI estimation operation is related to the number of NZP CSI-RS ports (such as the number of transmit antenna ports of TRP that UE can distinguish). For a downlink channel matrix For example, the number of columns N in H represents the number of transmit antenna ports of the TRP (up to 32), and the number of rows M in H represents the number of receive antenna ports of the UE. Therefore, N determines the computational complexity of channel estimation. In one possible implementation, the computational complexity of SVD / EVD is related to the spatial dimension, where the spatial dimension is determined by the number of spatial beams L. For example, a larger value of L increases the accuracy of the PMI and the computational complexity of each SVD / EVD.

[0124] In one possible implementation, in NR, TRP can configure multiple CSI reports simultaneously. Each CSI report can be bound to a CSI-RS resource set (CSI-RS resource set). This CSI-RS resource set can contain at least one CSI-RS resource. The UE can measure and report CSI on the at least one CSI-RS resource. Therefore, the number of CSI reports triggered by TRP, the number of CSI-RS resources contained in the CSI-RS resource set bound to the CSI report, and the number of ports on the CSI-RS resource will all affect the complexity of the UE's CSI channel estimation.

[0125] 2. CSI-RS multiplexing method:

[0126] In 5G NR technology, the CSI-RS for a single antenna port occupies one resource element (RE). CSI-RS supports multiple antenna ports occupying multiple RE resources, multiplexing them according to code division multiplexing (CDM) code groups, similar to the physical downlink shared channel (PDSCH) DM-RS CDM groups. For example, depending on the number of antenna ports, the multiplexing method can be configured as follows: no code division multiplexing; two frequency domain code division multiplexing groups; two frequency domain groups and two time domain groups, for a total of four groups; two frequency domain groups and four time domain groups, for a total of eight groups. Assume the code group size L∈{1, 2, 4, 8}. Based on the number of antenna ports, the number of code groups can be determined as N / L. When the 6G antenna scale is expanded to 1024, the resource overhead for CSI-RS will increase dramatically. Simultaneously, the number of codebooks for PMI feedback and the computational complexity of PMI will also increase dramatically.

[0127] 2. Communication method provided by this application:

[0128] FIG3 is a flow chart of a communication method provided by the present application. The communication method is applied to the communication system shown in FIG1 . For example, the communication method can be implemented by interaction between a first device and a second device. The first device can be a terminal or a device capable of implementing terminal functions, and the second device can be a network device or a device capable of implementing network device functions. The communication method includes the following steps:

[0129] S101, the second device sends a reference signal, the frequency domain position of the reference signal and the corresponding transmitting antenna port at the frequency domain position are a combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix; correspondingly, the first device receives the reference signal.

[0130] Among them, the reference signal may include but is not limited to CSI-RS, channel sounding reference signal (SRS), demodulation reference signal (DMRS), etc., and this application is mainly described by taking CSI-RS as an example. Among them, the frequency domain position of the reference signal and the corresponding transmitting antenna port at the frequency domain position are a combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix, that is, the reference signal can be a partial reference signal. For example, the partial reference signal only occupies part of the frequency domain positions and the transmitting antenna ports in all transmitting antenna ports and all frequency domain positions (such as only occupying the combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix), and the arrangement of the occupied part of the frequency domain positions and the transmitting antenna ports in the space formed by all transmitting antenna ports and all frequency domain positions is non-uniform.

[0131] Among them, the permutation matrix is ​​obtained based on the first projection matrix and the first decomposition method, and the first projection matrix is ​​obtained based on the training matrix and the second decomposition method. The training matrix is ​​obtained by the second device training the channel matrix of multiple time units, wherein the multiple time units can be multiple transmission time intervals (transport time intervals, TTIs) or time slots. That is, the training matrix, the first projection matrix and the permutation matrix can be multiple matrices obtained by the second device training and decomposing the channel matrix of multiple time units. In one possible implementation, the second device trains and decomposes the channel matrix of multiple time units to obtain the training matrix, the first projection matrix and the permutation matrix, which can specifically include the following process:

[0132] (1) The second device combines the channel matrices of multiple time units into a training matrix A.

[0133] Among them, the dimension (size) of A can be expressed as n*m, n=nTx*nRx*nSc, nTx represents the number of transmitting antenna ports, nRx represents the number of receiving antenna ports, nSc represents the number of frequency domain units, the granularity of the frequency domain unit can be RE, resource block (RB) or resource block group (RBG), etc., and m represents the number of symbols or terminals. For example, Figure 4 is a schematic diagram of a training process of a permutation matrix provided in this application. Among them, the training matrix A of the first part is a two-dimensional training matrix, the columns of the training matrix A include information of three dimensions: transmitting antenna ports, the number of receiving antenna ports and frequency domain resources, and the rows of the training matrix A include the number of symbols or the number of terminals.

[0134] (2) Decompose the training matrix A using the second decomposition method to obtain an intermediate matrix and a decomposition rank; select the column corresponding to the decomposition rank from the intermediate matrix to obtain the first projection matrix U.

[0135] The dimension of the first projection matrix U can be expressed as n*r, r represents the rank of the first projection matrix, and the value of r can be predefined, and r<<n, m>r. For example, in the second part of Figure 4, the second device performs truncated SVD decomposition on the training matrix A to obtain the first projection matrix U and projection coefficient C, where C=SV * , the dimension of S is r*r, V * The dimension is r*m. Optionally, the second decomposition method is, for example, singular value decomposition (SVD) or machine learning, and the final result is to obtain the first projection matrix. This application does not limit the specific decomposition method.

[0136] (3) The second device decomposes the first projection matrix U using the first decomposition method to obtain the permutation matrix P.

[0137] The dimensions of the permutation matrix P can be expressed as r*n. Since n=nTx*nRx*nSc (including the three dimensions of transmit antenna port, receive antenna port, and frequency domain position), the first index in the permutation matrix P corresponds to the combination of transmit antenna port, receive antenna port, and frequency domain position. For example, the first index in the permutation matrix P corresponds to the j-th receive antenna port receiving the reference signal position of the k-th transmit antenna port at the i-th frequency domain position, where i, j, and k are positive integers.

[0138] For example, the permutation matrix P can be expressed as: Among them, the first index of the permutation matrix P in this embodiment represents an index with a value of 1 in the permutation matrix P, and the combination of the frequency domain position and the transmitting antenna port corresponding to the first index indicates the combination of the frequency domain position and the transmitting antenna port of the reference signal. Optionally, the first index in the permutation matrix can also be an index with other values. For example, assuming that the values ​​in the permutation matrix P include 0 and 2 (or other non-zero values), the first index of the permutation matrix represents an index with a value of 2 (that is, a value not equal to 0) in the permutation matrix P. Optionally, the first decomposition method is, for example, an orthogonal triangular QR decomposition or a machine learning method, and the final result is to obtain a permutation matrix. This application does not limit the specific decomposition method.

[0139] For example, the third part of FIG4 shows the process of the second device performing the rotation QR decomposition on the first projection matrix U, such as extracting the conjugate transposed matrix U of the first projection matrix H , and then rearrange these linearly independent columns to obtain a permutation matrix P. In one possible implementation, the third portion of Figure 4 also shows a second projection matrix θ. The second projection matrix θ can be considered a low-dimensional permutation matrix, with the dimension of θ being r*r, where θ = P*U. Thus, according to the above process, the second device can determine the permutation matrix, thereby determining the position of the reference signal.

[0140] In one possible implementation, the second device sends a reference signal, which may specifically be a reference signal (e.g., CSI-RS) sent by the second device on a combined resource of a frequency domain position and a transmit antenna port corresponding to a first index in the permutation matrix. For example, assuming that the second device is an ORAN network element, the reference signal may be sent via an O-RU.

[0141] In a possible implementation, before the second apparatus sends the reference signal, the following operations may be performed:

[0142] (1) The second device determines a resource pattern of a reference signal according to the training matrix;

[0143] (2) The second device maps the ports in the resource pattern of the reference signal to resource units in the time domain and / or frequency domain.

[0144] The resource pattern of the reference signal includes one or more of a transmitting antenna port, a time domain resource, and a frequency domain resource. The second device may map a port (such as a transmitting antenna port) to REs in the time domain and / or frequency domain, thereby transmitting the reference signal on the time-frequency domain resources. In one possible implementation, the mapping relationship between the reference signal pattern and the time-frequency domain position of the reference signal may be a mapping relationship between the reference signal pattern and the position in the frequency domain and the spatial domain, or a mapping relationship between the reference signal pattern and the position in the time domain (assuming a one-to-one correspondence between the spatial domain and the time domain) and the frequency domain.

[0145] Optionally, when the ports in multiple reference signals are mapped to the same RE in the time domain and / or frequency domain, the second device can dynamically / configurably map the ports to the CDM group. That is, the second device can map n transmit antenna ports to the same CDM group, and the configuration of the n transmit antenna ports is specific to each terminal device (UE) and dynamically configurable. For example, Figure 5 is a schematic diagram of a dynamic CDM group provided in the present application. Compared with the traditional CDM group in which the ports are fixed, the dynamic CDM can map the ports of the terminal's reference signal to a specified CDM group for different terminals, and the ports mapped to the same CDM group by different terminals may not be exactly the same.

[0146] S102: The first device sends a first channel matrix or a second channel matrix.

[0147] The first channel matrix includes channel matrices for one or more groups of receive antenna ports corresponding to the combination of the frequency domain position of the reference signal and the transmit antenna port; the second channel matrix is ​​obtained by multiplying the first channel matrix by the inverse matrix of the second projection matrix. The frequency domain position of the reference signal and the combination of the transmit antenna port are known, and the one or more groups of receive antenna ports may be the receive antenna ports indicated by the base station to the terminal for feedback, or may be a number greater than the number of receive antenna ports indicated by the base station (such as some receive antenna ports), or may be all receive antenna ports.

[0148] In one possible implementation, the first device may determine the first channel matrix and determine the second channel matrix according to the frequency domain position corresponding to the first index in the permutation matrix and the combination of the transmitting antenna port and the receiving antenna port, and may include the following process:

[0149] (1) The first device determines the combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix and the channel matrix on the receiving antenna port indicated by the base station that the first device needs to feed back as the first channel matrix.

[0150] Among them, the combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix (for example, the index with a value of 1 in the permutation matrix) and the channel matrix on the receiving antenna port are the channel matrices paired on the frequency domain position, the transmitting antenna port, and the receiving antenna port (such as the channel matrix paired with the i-th frequency domain position, the k-th transmitting antenna, and the j-th receiving antenna). For example, Figure 6 is a schematic diagram of the relationship between the channel matrix of the transmitting antenna port, the receiving antenna port, and the frequency domain position and the first channel matrix provided by the present application. Among them, the horizontal axis represents the receiving antenna port, and the vertical axis represents the combination of the frequency domain position and the transmitting antenna port (wherein the frequency domain position and the transmitting antenna port are one-to-one corresponding, for example, the i-th frequency domain position carries the reference signal on the k-th transmitting antenna port). For the first device (the first device is the receiving end), the information fed back by the first device to the second device (the second device is the transmitting end) may not include the transmitting antenna port (wherein the frequency domain position and the transmitting antenna port are one-to-one corresponding and the transmitting antenna port is known to the transmitting end). In the channel matrix of receiving antenna ports and frequency domain positions shown in Figure 6, the position of the marked box is the combination of the frequency domain position and transmitting antenna port corresponding to the first index in the arrangement matrix and the receiving antenna port, that is, the channel matrix composed of the positions of the marked boxes is the first channel matrix.

[0151] (2) The first device multiplies the first channel matrix by the inverse matrix of the second projection matrix to obtain a second channel matrix.

[0152] The second channel matrix includes the channel matrix obtained by multiplying the first channel matrix by the inverse matrix of the second projection matrix. The values ​​in the second channel matrix obtained here have only mathematical significance. For example, Figure 7 is a schematic diagram of the relationship between the first channel matrix and the second channel matrix provided in this application. The first channel matrix is ​​equal to the product of the second projection matrix and the second channel matrix. That is, the second channel matrix is ​​obtained by multiplying the first channel matrix by the inverse matrix of the second projection matrix.

[0153] In another possible implementation, the first device determines the first channel matrix and determines the second channel matrix according to the combination of the frequency domain position corresponding to the first index in the permutation matrix and the transmitting antenna port and the receiving antenna port, which may include the following process:

[0154] (1) The first device determines a combination of a frequency domain position and a transmitting antenna port corresponding to a first index in the permutation matrix and a channel matrix on some or all receiving antenna ports as a first channel matrix.

[0155] Among them, the combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix (for example, the index with a value of 1 in the permutation matrix) and the channel matrix on some or all of the receiving antenna ports are the channel matrices of some or all of the receiving antenna ports at the frequency domain position where the reference signal is sent (for example, the i-th frequency domain position and the k-th transmitting antenna and some or all of the receiving antenna ports include the combination of the i-th frequency domain position and the k-th transmitting antenna port and the 1st receiving antenna port, up to the i-th frequency domain position and the k-th transmitting antenna port and the n-th receiving antenna port, where n is a positive integer). For example, Figure 8 is a schematic diagram of the relationship between the channel matrix of another transmitting antenna port, receiving antenna port and frequency domain position provided by the present application and the first channel matrix. Among them, the horizontal axis represents the receiving antenna port and the vertical axis represents the frequency domain position. For the first device (the first device is the receiving end), the information fed back by the first device may not include the transmitting antenna port; or, the vertical axis in Figure 8 may represent the combination of the frequency domain position and the transmitting antenna port (the transmitting end is known). In the channel matrices of all receiving antenna ports at the frequency domain positions shown in FIG8 , that is, the channel matrix shown in FIG8 is a first channel matrix.

[0156] (2) The first device multiplies the first channel matrix by the inverse matrix of the second projection matrix to obtain a second channel matrix.

[0157] The second channel matrix includes the channel matrix at the receiving antenna port and frequency domain position obtained by multiplying the first channel matrix by the inverse matrix of the second projection matrix. The specific implementation method can be referred to the corresponding description above and will not be repeated here.

[0158] In one possible implementation, after determining the first channel matrix, the first device may send the first channel matrix to the second device. This sending method can be referred to as explicit channel matrix feedback. That is, the first device directly feeds back the channel matrix to the second device. In another possible implementation, after determining the first channel matrix, the first device multiplies the first channel matrix by the inverse of the second projection matrix to obtain a second channel matrix, and then sends the second channel matrix to the second device. This sending method can be referred to as implicit channel matrix feedback.

[0159] Optionally, after S102, the following steps may be further included: the first device reconstructs the entire downlink channel according to the first channel matrix or the second channel matrix. For example, the first device may multiply the second channel matrix C with the first projection matrix U to obtain the reconstructed downlink channel

[0160] In this embodiment, the reference signal received by the first device can be a partial reference signal, thereby reducing the pilot overhead of transmitting the reference signal. Furthermore, compared to the feedback method indicated by the precoding matrix, the first channel matrix or the second channel matrix fed back by the first device provides less feedback information (e.g., only one channel matrix needs to be fed back), thereby reducing the reference signal feedback overhead.

[0161] 3. The specific process of S102 is described in detail below.

[0162] After receiving the reference signal, the first device may perform channel estimation on the reference signal to obtain a first channel matrix or a second channel matrix.

[0163] Example 1: The first device performs channel estimation based on the reference signal, obtains and sends a first channel matrix.

[0164] For example, FIG9 is a flow chart of a first apparatus provided in the present application performing channel estimation based on a reference signal, obtaining and sending a first channel matrix, including the following steps:

[0165] S201: A first device determines a first channel matrix and / or a second channel matrix according to a reference signal.

[0166] For example, after receiving the reference signal, the first device can determine the combination of the frequency domain position and the transmit antenna port corresponding to the first index in the permutation matrix. Therefore, the first device determines the first channel matrix and the second channel matrix based on the combination of the frequency domain position and the transmit antenna port corresponding to the first index in the permutation matrix, as well as the receive antenna port. The specific implementation method is described above and will not be repeated here.

[0167] Optionally, after S201, the following steps are further included:

[0168] The second device sends fourth information to the first device, where the fourth information is used to instruct the terminal device to feed back the first channel matrix or the second channel matrix; correspondingly, the first device receives the fourth information.

[0169] For example, the base station can pre-configure the CSI feedback method to the UE, such as configuring the UE to explicitly feedback the channel matrix or implicitly feedback the channel matrix, and the UE can determine whether to perform explicit feedback (such as sending the first channel matrix) or implicit feedback (such as sending the second channel matrix) based on the fourth information. Optionally, the fourth information can also indicate the combination of the receiving antenna port and the frequency domain position corresponding to the first index in the feedback arrangement matrix of the terminal device, or the channel matrix of all transmitting antenna ports of the frequency domain position corresponding to the first index in the feedback arrangement matrix.

[0170] S202: The first device sends a first channel matrix to the second device.

[0171] According to the description in the above embodiment, the first channel matrix may include the following two cases:

[0172] Case 1: The first channel matrix is ​​determined based on a group or multiple groups of receiving antenna ports corresponding to the combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix. For example, in case 1, the first channel matrix is ​​represented as A(i), and the number of elements of A(i) is r, where r is the number of combinations of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix, and its value is equal to the rank of the first projection matrix. The first channel matrix includes a combination of one or more groups of receiving antenna ports at the frequency domain position of the reference signal, and the combination of the receiving antenna ports at the frequency domain position of any group of reference signals includes the i-th frequency domain position and the k-th transmitting antenna port and the j-th receiving antenna port; i, j and k are positive integers. For example, in case 1, the first device feeds back to the second device the channel matrix of one or more groups of receiving antenna ports at the RE position in the frequency domain, as shown in Figure 6.

[0173] In one possible implementation, the base station may indicate to the terminal device the index of the receiving antenna port that needs feedback. For example, the second device sends the second information to the first device; correspondingly, the first device receives the second information, and the second information is used to indicate the index of the receiving antenna port that needs feedback. Among them, the position of the receiving antenna port that needs feedback may be the position of the port that sends the reference signal on the base station side. Optionally, when the base station indicates the index of the receiving antenna port that needs feedback to the terminal device, the terminal device may feedback the combination of the frequency domain position and the transmitting antenna port corresponding to the first index and the channel matrix on the receiving antenna port that needs feedback, or may feedback the combination of the frequency domain position and the transmitting antenna port corresponding to the first index and the channel matrix on more receiving antenna ports, which is not limited in this application.

[0174] Case 2: The first channel matrix is ​​determined based on the combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix and some or all of the receiving antenna ports. For example, in Case 2, the number of elements of the first channel matrix A(i) is r*n, where r is the number of combinations of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix, and its value is equal to the rank of the first projection matrix, and n is the number of some or all of the receiving antenna ports. For example, in Case 2, the first device feeds back the channel matrix of some or all of the receiving antenna ports at the RE position in the frequency domain (such as the channel matrix of the 1st to nth receiving antenna ports at the RE position in the frequency domain) to the second device, as shown in Figure 8.

[0175] Optionally, in case 2, since a combination of some or all receiving antenna ports at the frequency domain position of the sent reference signal is fed back, the second device does not need to indicate to the first device the position of the receiving antenna port that needs to be fed back.

[0176] In this example 1, after the terminal performs channel estimation, it performs explicit CSI feedback, that is, directly feeds back the first channel matrix obtained by channel estimation. The explicit CSI feedback in Example 1 includes two cases: feedback of the channel matrix of the indicated receiving antenna port and the frequency domain position, or feedback of the channel matrix of some or all receiving antenna ports and the frequency domain position. Among them, compared with case 2, case 1 requires fewer feedback channel matrices, but a part of the air interface resources needs to be used to indicate the index of the receiving antenna port. Compared with the existing 5G NR solution, case 1 and case 2 require less CSI-RS pilot overhead, and less feedback information is required, which is conducive to reducing feedback overhead.

[0177] Example 2: The first device performs channel estimation based on a reference signal and sends a first channel matrix.

[0178] For example, FIG10 is a flow chart of another first apparatus provided in the present application performing channel estimation based on a reference signal, obtaining and sending a first channel matrix, including the following steps:

[0179] S301: A first device performs channel estimation based on a reference signal to determine a first channel matrix.

[0180] The specific implementation of S301 can refer to the corresponding description in S201 and the description of the optional steps, which will not be repeated here.

[0181] S302: The first device multiplies the first channel matrix by the inverse matrix of the second projection matrix to obtain a second channel matrix.

[0182] The second channel matrix includes the channel matrix at the receiving antenna port and frequency domain position obtained by multiplying the first channel matrix by the inverse matrix of the second projection matrix. The relationship between the first channel matrix and the second channel matrix is ​​shown in FIG7 .

[0183] Optionally, before S302, the following steps are further included:

[0184] The second device sends third information to the first device; correspondingly, the first device receives the third information, where the third information is used to indicate the second projection matrix.

[0185] For example, the base station indicates the second projection matrix to the terminal through control signaling (such as RRC / MAC CE / DCI). It can be understood that the second projection matrix is ​​a lower-dimensional projection matrix than the first projection matrix, contains less information, and is beneficial to reducing computational overhead when participating in calculations.

[0186] In a possible implementation, the third information includes the second projection matrix θ. For example, the base station may send the second projection matrix θ to the terminal, and the terminal may directly use the second projection matrix θ for calculation.

[0187] In one possible implementation, the third information includes a permutation matrix P. For example, if the terminal already knows the first projection matrix U, the base station may send the permutation matrix to the terminal. The terminal may multiply the permutation matrix P by the first projection matrix U to obtain a second projection matrix θ. The terminal may subsequently use the second projection matrix θ for calculations.

[0188] In one possible implementation, the third information includes the first index in the permutation matrix. For example, if the terminal already knows the size of the first projection matrix U and the permutation matrix P, the base station may indicate only the first index in the permutation matrix. The terminal can then determine the second projection matrix θ based on the index value. The terminal can then use the second projection matrix θ for calculations.

[0189] Optionally, the second projection matrix may also be trained and reported by the terminal. For example, if the terminal knows the first projection matrix U and the permutation matrix P, the second projection matrix θ may be obtained by training based on the first projection matrix U and the permutation matrix P.

[0190] S303: The first device sends a second channel matrix to the second device.

[0191] According to the description in the above embodiment, the second channel matrix includes the channel matrix at the receiving antenna port and frequency domain position obtained by multiplying the first channel matrix by the inverse matrix of the second projection matrix. Specifically, the second channel matrix may include the following two cases:

[0192] Case 1: When the first channel matrix is ​​the channel matrix at the first position in the permutation matrix, the number of elements of the first channel matrix A(i) is r, and the number of elements of the second channel matrix C is r. For example, in Case 1, the first device feeds back to the second device the coefficients corresponding to the channel matrices of one or more groups of receive antenna ports at RE positions in the frequency domain.

[0193] In one possible implementation, when a terminal device feeds back the combination of a receive antenna port and a frequency domain position corresponding to the first index in the permutation matrix, the base station needs to indicate to the terminal device the position of the receive antenna port for which feedback is required. For the specific implementation, refer to the corresponding description in Example 1 and will not be repeated here.

[0194] Case 2: When the first channel matrix includes combinations of some or all receive antenna ports at the frequency domain locations where reference signals are transmitted, the number of elements in the first channel matrix A(i) is r*n, and the number of elements in the second channel matrix C is r*n. For example, in Case 2, the first device feeds back to the second device the coefficients corresponding to the channel matrices of some or all receive antenna ports at the RE locations in the frequency domain (e.g., the coefficients corresponding to the channel matrices of the first to nth receive antenna ports at the RE locations in the frequency domain).

[0195] Optionally, in case 2, since a combination of some or all receiving antenna ports at the frequency domain position of the sent reference signal is fed back, the second device does not need to indicate to the first device the position of the receiving antenna port that needs to be fed back.

[0196] In this example 2, after the terminal performs channel estimation, it performs implicit CSI feedback, that is, feeds back the second channel matrix. The implicit CSI feedback in Example 2 includes two cases: feedback of the coefficients corresponding to the channel matrix of the indicated receiving antenna port and the frequency domain position, or feedback of the coefficients corresponding to the channel matrix of some or all receiving antenna ports and the frequency domain position. Among them, compared with case 2, case 1 requires fewer feedback channel matrices, but a part of the air interface resources needs to be used to indicate the index of the receiving antenna port. Compared with the existing 5G NR solution, case 1 and case 2 require less CSI-RS pilot overhead, and less feedback information is required, which is conducive to reducing feedback overhead.

[0197] 4. When there is only one or a few ports on the same frequency domain resource, the base station needs to perform CDM to increase the transmission power.

[0198] For example, Figure 11 is a schematic diagram of performing CDM to increase transmission power under a CSI-RS port provided by the present application. Among them, the CSI-RS ports mapped to the frequency domain resources shown on the left side of Figure 11 are very few (such as there is only one CSI-RS port on each frequency domain RE), and the channel estimation result obtained by performing channel estimation based on the CSI-RS may be inaccurate. Therefore, the present application proposes that CDM can be performed on the CSI-RS port on each frequency domain RE to improve the quality of channel estimation. For example, the CSI-RS port mapped to each frequency domain RE shown on the right side of Figure 11 is expanded from 1 to 4, and the 4 ports belong to the same CDM group. After the expansion, the number of CSI-RS ports mapped to each frequency domain RE is 4, and CDM can be performed to improve the quality of channel estimation.

[0199] In one possible implementation, the first device may perform channel estimation based on the extended CSI-RS. For example, for channels corresponding to multiple CSI-RS at the same frequency domain position (whose frequency domain characteristics are consistent), the UE may use a spatial domain filter to perform channel estimation.

[0200] In one possible implementation, after performing channel estimation on the CSI-RS after CDM, the first device can perform a de-CDM operation on the UE side, thereby obtaining the required channel matrix in the specified port and frequency domain (such as obtaining the channel matrix under the CSI-RS port before CDM). The de-CDM operation on the UE side can refer to the existing de-CDM operation, and this application is not limited.

[0201] In one possible implementation, the first device sends the first channel matrix or the second channel matrix to the second device, including the first device sending the channel matrix obtained by decompressing the CDM process at the designated port and frequency domain to the second device. The channel matrix obtained by decompressing the CDM process at the designated port and frequency domain may be a channel matrix at a position with a value of 1 in the permutation matrix, or a combination of some or all receive antenna ports at a frequency domain position at which a reference signal is transmitted. For specific implementation methods, refer to the corresponding description in Section 3 and are not further described here.

[0202] In this embodiment, when only one or a few ports on the same frequency domain resource result in low transmit power and poor channel estimation, CSI-RS ports to be detected can be artificially distributed in the frequency domain to improve the SNR and thus the channel estimation effect. In addition, the UE can obtain the required channel matrix by performing a CDM demultiplexing operation.

[0203] 5. A simplified approach is used to perform channel estimation based on the characteristics of the reference signal.

[0204] Since the reference signal received by the first device has the characteristics of a partial reference signal (e.g., the reference signal occupies only a portion of the frequency domain positions and transmit antenna ports among all transmit antenna ports and all frequency domain positions), the first device may perform channel estimation on the reference signal in a simplified manner. For example, the first device may perform channel estimation on the reference signal in the following manners, including but not limited to:

[0205] Method 1: The first device uses a single sequence to perform channel estimation on reference signals at different frequency domain locations, where the frequency domain location and transmit antenna port of the reference signal are determined based on the combination of the frequency domain location and transmit antenna port corresponding to the first index in the permutation matrix. For example, the UE can use a single sequence (the ports corresponding to each sequence may be different, but the single sequence can be used) to estimate the REs of the CSI-RS in the frequency domain.

[0206] Method 2: The first device uses multiple filters to perform channel estimation on reference signals at different frequency domain locations. For example, the filters used at different frequency domain locations may be different, and the UE may use different filters to estimate REs of CSI-RS in the frequency domain.

[0207] Method 3: The first device uses a spatial filter to perform channel estimation on the reference signal at the same frequency domain position. For example, the UE can perform spatial filtering on the reference signal on the port to estimate the RE of the CSI-RS at the same frequency domain position.

[0208] In one possible implementation, the first apparatus estimates the REs of reference signals at the same or different frequency domain locations, determines a combination of the frequency domain location and the transmit antenna port, and the receive antenna port, and determines a first channel matrix. For a detailed description of the first channel matrix, reference may be made to the corresponding description in S102 and will not be repeated here. That is, this embodiment can be applied to the embodiments shown in Figures 3, 9, and 10.

[0209] 6. The performance of the communication method provided in this application is analyzed below.

[0210] For example, Table 1 is a link simulation parameter table corresponding to the communication method provided in this application. In this application, it is assumed that the 3GPP CDL-A channel model is adopted, and the simulation scenario is configured with reference to Table 1. It should be noted that the reference signal used in the following simulation analysis is CSI-RS as an example.

[0211] Table 1: Link simulation parameters

[0212] Among them, for the simulation of this application, it is assumed that: actual channel estimation is performed on the UE side; CDM is performed in the time dimension to achieve port multiplexing; a correlation algorithm is used for channel estimation; an actual difference algorithm is used; and ideal CSI feedback is considered.

[0213] For example, Figure 12 is a simulation diagram of a reference signal pattern trained using different TTIs provided by the present application. Under the simulation conditions and simulation channels shown in Table 1, the reference signal pattern trained using different TTIs by the communication method provided by the present application is shown in Figure 12. As can be seen from Figure 12, the reference signal pattern trained by the communication method provided by the present application only occupies a portion of the frequency domain position and transmit antenna port, which helps reduce the pilot overhead of transmitting the reference signal.

[0214] For example, Table 2 is a comparison table of RE resource overheads of channel training reference signals using different TTIs provided in this application.

[0215] Table 2: Comparison of RE resource overhead using channel training reference signals at different TTIs

[0216] According to Table 2, the communication method provided in this application is trained to obtain a reference signal pattern, which can significantly reduce the overhead of RE resources compared to the existing 5G solution.

[0217] For example, Figure 13 is a simulation diagram of the average downlink rate after channel estimation using a reference signal obtained through 100 TTI training under different SNRs using the communication method provided by this application. As shown in Figure 13, compared to existing 5G-NR solutions, the pilot overhead is reduced to less than 3%. Furthermore, under high SNR conditions, the reference signal detection scheme provided by this application performs well, with the difference from the normalized average rate under ideal channel conditions being less than 1%.

[0218] In order to realize the various functions in the method provided by the present application, the device or equipment provided by the present application may include a hardware structure and / or a software module, and realize the above-mentioned various functions in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether a certain function among the above-mentioned functions is executed in the form of a hardware structure, a software module, or a hardware structure plus a software module depends on the specific application and design constraints of the technical solution. The division of modules in the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, the various functional modules in the various embodiments of the present application can be integrated into a processor, or they can exist physically separately, or two or more modules can be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software functional modules.

[0219] Figure 14 is a schematic diagram of a communication device provided by the present application. The device may include a module corresponding to the method / operation / step / action described in any of the embodiments shown in Figures 3 to 11. The module may be a hardware circuit, software, or a combination of hardware circuit and software.

[0220] The apparatus 1400 includes a communication unit 1401 and a processing unit 1402, configured to implement the methods executed by the devices in the aforementioned embodiments. The communication unit 1401 is also called a transceiver unit, which includes a transmitting unit and a receiving unit. The transmitting unit is configured to transmit signals, and the receiving unit is configured to receive signals.

[0221] In one possible implementation, the device is a terminal, or is located in a terminal. Specifically, the communication unit 1401 is used to receive a reference signal, and the frequency domain position of the reference signal and the corresponding transmitting antenna port at the frequency domain position are a combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix; the permutation matrix is ​​obtained by decomposing the first projection matrix, and the first projection matrix is ​​determined based on the rank obtained by performing singular value decomposition on the training matrix. The communication unit 1401 is also used to send a first channel matrix or a second channel matrix, the first channel matrix is ​​determined based on the combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix and the receiving antenna port, the second channel matrix is ​​determined based on the first channel matrix and the second projection matrix, and the second projection matrix is ​​determined based on the permutation matrix and the first projection matrix or indicated by the second device.

[0222] The specific execution process of the communication unit 1401 and the processing unit 1402 in this embodiment can refer to the description of the steps executed by the terminal in the method embodiment above, as well as the related description, which will not be repeated here. In the communication method implemented by the device, the received reference signal can be a partial reference signal, which is beneficial to reducing the pilot overhead of sending the reference signal. In addition, the first channel matrix or the second channel matrix fed back has less feedback information than the feedback method indicated by the precoding matrix (for example, only one channel matrix needs to be fed back), which can reduce the feedback overhead of the reference signal.

[0223] In one possible implementation, the device is a network device, or is located in a network device. Specifically, the communication unit 1401 is used to send a reference signal, and the frequency domain position of the reference signal and the corresponding transmitting antenna port at the frequency domain position are a combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix; the permutation matrix is ​​obtained by decomposing the first projection matrix, and the first projection matrix is ​​determined by performing singular value decomposition on the training matrix and the rank obtained based on the singular value decomposition. The communication unit 1401 is also used to receive a first channel matrix or a second channel matrix, the first channel matrix is ​​determined based on the combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix and the receiving antenna port, the second channel matrix is ​​determined based on the first channel matrix and the second projection matrix, and the second projection matrix is ​​determined based on the permutation matrix and the first projection matrix or indicated by the second device.

[0224] The specific execution process of the communication unit 1401 and the processing unit 1402 in this embodiment can refer to the description of the steps executed by the network device in the previous method embodiment, as well as the related description, which will not be repeated here. The communication method implemented by the device can only occupy part of the frequency domain position and the transmitting antenna port to send the reference signal, thereby reducing the pilot overhead of sending the reference signal. In addition, the first channel matrix or the second channel matrix fed back is less information than the feedback method indicated by the precoding matrix (such as only one channel matrix needs to be fed back), which is beneficial to reducing the feedback overhead of the reference signal.

[0225] In one possible implementation, when the communication device is a chip, the chip includes a transceiver unit and a processing unit. The transceiver unit may be an input / output circuit or a communication interface; the processing unit may be a processor, microprocessor, integrated circuit, or logic circuit integrated on the chip.

[0226] The present application also provides a communication device, see Figure 15, another structural diagram of the communication device of the present application embodiment. The communication device can be used to execute the steps performed by the network device or terminal in the above method embodiment, and reference can be made to the relevant description in the above method embodiment.

[0227] The communication device includes a processor 1501. Optionally, the communication device further includes a memory 1502 and a transceiver 1503.

[0228] In a possible implementation, the processor 1501 , the memory 1502 , and the transceiver 1503 are connected via buses, and computer instructions are stored in the memory.

[0229] Optionally, the processing unit 1402 in the aforementioned embodiment may be specifically the processor 1501 in this embodiment, and thus the specific implementation of the processor 1501 is not described in detail. The communication unit 1401 in the aforementioned embodiment may be specifically the transceiver 1503 in this embodiment, and thus the specific implementation of the transceiver 1503 is not described in detail.

[0230] In this application, a processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, and may implement or execute the methods, steps, and logic block diagrams disclosed in this application. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in this application may be directly executed by a hardware processor, or by a combination of hardware and software modules within the processor.

[0231] In the present application, the memory may be a non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), or a volatile memory, such as a random-access memory (RAM). The memory is any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory in the present application may also be a circuit or any other device that can implement a storage function, for storing program instructions and / or data.

[0232] The present application provides another communication device, which includes a processor and an interface. Optionally, it also includes a memory, the processor is coupled to the memory, and the processor is configured to read and execute computer instructions stored in the memory to implement the communication method in the embodiments shown in Figures 3 to 11.

[0233] The present application also provides a communication system including a first device and a second device. The first communication device is configured to execute all or part of the steps executed by the first device in the above embodiment. The second device is configured to execute all or part of the steps executed by the second device in the above embodiment.

[0234] The present application provides a computer-readable storage medium. The computer-readable storage medium stores a program or instruction. When the program or instruction is executed on a computer, the computer executes the communication method in the embodiments shown in Figures 3 to 11.

[0235] The present application provides a computer program product. The computer program product includes instructions. When the instructions are executed on a computer, the computer executes the communication method in the embodiments shown in Figures 3 to 11.

[0236] The present application provides a chip or chip system, which includes at least one processor and an interface, the interface and the at least one processor are interconnected by lines, and the at least one processor is used to run computer programs or instructions to execute the communication method in the embodiments shown in Figures 3 to 11.

[0237] The interface in the chip may be an input / output interface, a pin, or a circuit.

[0238] The chip system may be a system on chip (SOC) or a baseband chip, wherein the baseband chip may include a processor, a channel encoder, a digital signal processor, a modem, an interface module, and the like.

[0239] In one implementation, the chip or chip system described above in this application further includes at least one memory, in which instructions are stored. The memory may be a storage unit within the chip, such as a register, a cache, etc., or a storage unit of the chip (e.g., a read-only memory, a random access memory, etc.).

[0240] The technical solutions provided in this application can be implemented in whole or in part through software, hardware, firmware, or any combination thereof. When implemented using software, they can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in this application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a terminal, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital video disc (DVD)), or a semiconductor medium.

[0241] In this application, under the premise that there is no logical contradiction, the various embodiments may reference each other, for example, the methods and / or terms between method embodiments may reference each other, for example, the functions and / or terms between device embodiments may reference each other, for example, the functions and / or terms between device embodiments and method embodiments may reference each other.

[0242] Obviously, those skilled in the art may make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include these modifications and variations.

Claims

1. A communication method, characterized in that: include: Receive a reference signal, wherein the frequency domain position of the reference signal and the transmitting antenna port corresponding to the frequency domain position are a combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix; the permutation matrix is ​​obtained according to the first projection matrix and the first decomposition method, and the first projection matrix is ​​obtained according to the training matrix and the second decomposition method; Send a first channel matrix or a second channel matrix, wherein the first channel matrix is ​​determined according to a combination of a frequency domain position corresponding to a first index in the arrangement matrix and a transmitting antenna port and a receiving antenna port, and the second channel matrix is ​​determined according to the first channel matrix and a second projection matrix, and the second projection matrix is ​​determined according to the arrangement matrix and the first projection matrix or is indicated by a second device.

2. The method according to claim 1, characterized in that The first channel matrix includes channel matrices on one or more groups of receiving antenna ports corresponding to a combination of a frequency domain position of the reference signal and a transmitting antenna port; The second channel matrix is ​​obtained by multiplying the first channel matrix by the inverse matrix of the second projection matrix.

3. The method according to claim 2, characterized in that The number of elements of the first channel matrix or the number of elements of the second channel matrix is ​​r; wherein r is the number of combinations of frequency domain positions and transmitting antenna ports corresponding to the first index in the permutation matrix.

4. The method according to claim 2 or 3, characterized in that: The method further comprises: receiving second information, where the second information is used to indicate an index of a receiving antenna port that the first device needs to feedback; The first channel matrix includes a channel matrix on the receiving antenna port requiring feedback corresponding to a combination of the frequency domain position of the reference signal and the transmitting antenna port.

5. The method according to claim 2, characterized in that: The first channel matrix includes channel matrices on some or all receiving antenna ports corresponding to a combination of the frequency domain position of the reference signal and the transmitting antenna port.

6. The method according to claim 5, characterized in that The number of elements of the first channel matrix or the number of elements of the second channel matrix is ​​r*n; wherein r is the number of combinations of frequency domain positions and transmitting antenna ports corresponding to the first index in the arrangement matrix, and n is the number of some or all receiving antenna ports.

7. The method according to any one of claims 1 to 6, characterized in that: The method further comprises: receiving third information, wherein the third information includes the second projection matrix; or, The third information includes information for indicating the second projection matrix.

8. The method according to any one of claims 1 to 7, characterized in that: The method further comprises: Fourth information is received, where the fourth information is used to instruct the first device to feed back the first channel matrix or the second channel matrix.

9. A communication method, characterized in that: include: Sending a reference signal, wherein the frequency domain position of the reference signal and the corresponding transmitting antenna port at the frequency domain position are a combination of the frequency domain position and the transmitting antenna port corresponding to the first index in the permutation matrix; the permutation matrix is ​​obtained according to the first projection matrix and the first decomposition method, and the first projection matrix is ​​obtained according to the training matrix and the second decomposition method; A first channel matrix or a second channel matrix is ​​received, wherein the first channel matrix is ​​determined according to a combination of a frequency domain position corresponding to a first index in the arrangement matrix and a transmitting antenna port and a receiving antenna port, and the second channel matrix is ​​determined according to the first channel matrix and a second projection matrix, and the second projection matrix is ​​determined according to the arrangement matrix and the first projection matrix or is indicated by a second device.

10. The method according to claim 9, characterized in that The first channel matrix includes channel matrices on one or more groups of receiving antenna ports corresponding to a combination of a frequency domain position of the reference signal and a transmitting antenna port; The second channel matrix is ​​obtained by multiplying the first channel matrix by the inverse matrix of the second projection matrix.

11. The method according to claim 10, characterized in that The number of elements of the first channel matrix or the number of elements of the second channel matrix is ​​r; wherein r is the number of combinations of frequency domain positions and transmitting antenna ports corresponding to the first index in the permutation matrix.

12. The method according to claim 10 or 11, characterized in that: The method further comprises: Sending second information, where the second information is used to indicate an index of a receiving antenna port that the first device needs to feedback; The first channel matrix includes a channel matrix on the receiving antenna port requiring feedback corresponding to a combination of the frequency domain position of the reference signal and the transmitting antenna port.

13. The method according to claim 10, characterized in that The first channel matrix includes channel matrices on some or all receiving antenna ports corresponding to a combination of the frequency domain position of the reference signal and the transmitting antenna port.

14. The method according to claim 13, characterized in that The number of elements of the first channel matrix or the number of elements of the second channel matrix is ​​r*n; wherein r is the number of combinations of frequency domain positions and transmitting antenna ports corresponding to the first index in the arrangement matrix, and n is the number of some or all receiving antenna ports.

15. The method according to any one of claims 9 to 14, characterized in that: The method further comprises: sending third information, wherein the third information includes the second projection matrix; or, The third information is used to indicate the second projection matrix.

16. The method according to any one of claims 9 to 15, characterized in that The first projection matrix is ​​obtained according to the training matrix and the second decomposition method, including: Decomposing the training matrix using the second decomposition method to obtain an intermediate matrix and a decomposition rank; A first projection matrix is ​​obtained by selecting a column corresponding to the decomposed rank from the intermediate matrix.

17. The method according to any one of claims 9 to 16, characterized in that: The method further comprises: Determining a resource pattern of the reference signal according to the training matrix; The ports in the resource pattern of the reference signal are mapped to resource units in the time domain and / or frequency domain.

18. The method according to claim 17, characterized in that Mapping the ports in the resource pattern to resource units in the time domain and / or frequency domain according to the resource pattern includes: Mapping n transmit antenna ports to the same code division multiplexing group; The configuration of the n transmitting antenna ports is for each terminal device and is dynamically configurable.

19. The method according to any one of claims 9 to 18, characterized in that: The method further comprises: Send fourth information, where the fourth information is used to instruct the terminal device to feed back the first channel matrix or the second channel matrix.

20. A communication device, characterized in that: The method comprises a communication unit and a processing unit, wherein the communication unit and the processing unit are used to execute the method according to any one of claims 1 to 8 or 9 to 19.

21. A communication device, characterized in that: include: A processor and a memory, wherein the memory is used to store instructions, and when the instructions are executed by the processor, the communication device executes the method according to any one of claims 1 to 8 or 9 to 19.

22. A communication system, characterized in that: The method comprises a first device and / or a second device, wherein the first device is used to execute the method according to any one of claims 1 to 8, and the second device is used to execute the method according to any one of claims 9 to 19.

23. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed on a computer, the computer is caused to perform the method according to any one of claims 1 to 8 or 9 to 19.

24. A chip system, characterized in that: The chip system comprises a processor and an interface, wherein the processor is configured to execute a computer program so that the chip system implements the method as claimed in any one of claims 1 to 8 or 9 to 19.

25. A computer program product, characterized in that The method comprises instructions which, when executed on a computer, cause the computer to perform the method according to any one of claims 1 to 8 or 9 to 19.

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