Downlink transmission method and apparatus

Abstract

An embodiment of the present application provides a transmission method and apparatus. The method includes the steps of: a first network device generating first information, the first information indicating at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook, and the weighting coefficients corresponding to the at least one codebook are used to determine a first beamforming matrix; and the first network device transmitting the first information to a second network device. Based on the present application, the first network device transmits the first information to the second network device instead of transmitting a beamforming matrix, so that the amount of data transmitted by the first network device to the second network device can be reduced.

Description

[Technical field]

[0001] This application claims priority to Chinese Patent Application No. 202210191609.6, entitled "TRANSMISSION METHOD AND APPARATUS," filed with the State Intellectual Property Office of the People's Republic of China on February 28, 2022, which is hereby incorporated by reference in its entirety.

[0002] TECHNICAL FIELD Embodiments of the present application relate to the field of communications, and more particularly, to a transmission method and apparatus. [Background technology]

[0003] In the 5th generation (5G) communication system, with the increase in bandwidth and number of antennas, the amount of data exchanged between a baseband unit (BU) and a radio unit (RU) through the fronthaul interface increases by several tens of times. Even if the data exchanged between the BU and the RU is compressed at a higher compression rate, the amount of data exchanged between the BU and the RU can still reach 100Gbps. To solve the problem of the sudden increase in data volume on the fronthaul interface, in 5G, the BU is divided into two parts, baseband high (BBH) and baseband low (BBL). The BBL is usually deployed in the RU or near the RU. The BBH and BBL are connected through the fronthaul interface, and the BBH and BBL perform different baseband processing functions separately to reduce the amount of data exchanged between the BBH and BBL through the fronthaul interface.

[0004] In massive multiple input multiple output (massive MIMO) scenarios, it is necessary to exchange beamforming matrices between BBH and BBL. Therefore, it is necessary to propose a method to exchange beamforming matrices between BBH and BBL using a small amount of data. Summary of the Invention [Means for solving the problem]

[0005] SUMMARY OF THE DISCLOSURE The embodiments of the present application provide a transmission method and apparatus to reduce the amount of data exchanged between a first network device and a second network device.

[0006] According to a first aspect, a transmission method is provided, the method including: a first network device generating first information, the first information indicating at least one codebook and a weighting factor matrix corresponding to the at least one codebook, the at least one codebook and the weighting factors corresponding to the at least one codebook being used to determine a first beamforming matrix; and a first network device transmitting the first information to a second network device.

[0007] Based on the above technical solution, the first network device sends first information indicating at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook to the second network device instead of sending a beamforming matrix, so that the amount of data sent by the first network device to the second network device can be reduced. For example, the first information can indicate at least one codebook by using a codebook index, that is, the first information can include an index of at least one codebook, and the data amount of the index of the at least one codebook is much less than the data amount of the entire beamforming matrix.

[0008] For example, the first network device is a control device and the second network device is a radio frequency device, or the first network device is a radio frequency device and the second network device is a control device. The radio frequency device has a baseband processing function. For example, the radio frequency device may be a BBL.

[0009] Referring to the first aspect, in some implementations of the first aspect, the first information indicates a column vector or a row vector included in at least one codebook.

[0010] Referring to the first aspect, in some implementations of the first aspect, the at least one codebook includes a first codebook, for example, the first codebook is a spatial domain codebook.

[0011] Referring to the first aspect, in some implementations of the first aspect, the at least one codebook includes a first codebook and a second codebook, for example, the first codebook is a spatial domain codebook and the second codebook is a frequency domain codebook.

[0012] Referring to the first aspect, in some implementations of the first aspect, the first beamforming matrix includes a first stage matrix and a second stage matrix, the at least one codebook includes a first codebook and a third codebook, a weighting coefficient matrix corresponding to the at least one codebook corresponds to the first codebook, the first codebook and the weighting coefficient matrix are used to determine the first stage matrix, and the analog domain codebook is used to determine the second stage matrix.

[0013] For example, the first codebook is a spatial domain codebook and the third codebook is an analog domain codebook.

[0014] Based on the above technical solution, the first information sent by the first network device to the second network device further indicates a third codebook, so that the second network device can determine a second stage matrix according to the third codebook. Therefore, the second network device can perform secondary beamforming on the downlink transmission signal according to the second stage matrix, and a more accurate beam direction is realized.

[0015] Referring to the first aspect, in some implementations of the first aspect, the first beamforming matrix includes a first stage matrix and a second stage matrix, the at least one codebook includes a first codebook, a second codebook, and a third codebook, a weighting coefficient matrix corresponding to the at least one codebook corresponds to the first codebook and the second codebook, the first codebook, the second codebook, and the weighting coefficient matrix are used to determine the first stage matrix, and the third codebook is used to determine the second stage matrix.

[0016] For example, the first codebook is a spatial domain codebook, the second codebook is a frequency domain codebook, and the third codebook is an analog domain codebook.

[0017] Based on the above technical solution, the first information sent by the first network device to the second network device further indicates a third codebook, so that the second network device can determine a second stage matrix according to the third codebook. Thus, the second network device can perform secondary beamforming for downlink transmission based on the second stage matrix, and a more accurate beam direction is realized.

[0018] Referring to the first aspect, in some implementations of the first aspect, the method further includes a step of the first network device determining, based on a second beamforming matrix and at least one codebook set, at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook, wherein the second beamforming matrix is ​​determined based on one or more of a beamforming matrix determined based on a sounding reference signal (SRS) measurement channel, a beamforming matrix determined based on a channel state information reference signal (CSI-RS) measurement channel, a beamforming matrix determined based on a demodulation reference signal (DMRS) measurement channel, and a static beamforming matrix.

[0019] With reference to the first aspect, in some implementations of the first aspect, the first network device determining the at least one codebook and a weighting factor matrix corresponding to the at least one codebook based on the second beamforming matrix and the at least one codebook set includes the first network device projecting the second beamforming matrix onto the at least one codebook set to obtain the at least one codebook and the weighting factor matrix corresponding to the at least one codebook that maximizes channel capacity and / or maximizes channel throughput.

[0020] Based on the above technical solution, the first network device can determine a second beamforming matrix according to one or more of the above beamforming matrices, and generate first information according to the second beamforming matrix. Correspondingly, the performance of the first beamforming matrix determined by the second network device based on the first information is better, so that the downlink transmission performance can be improved.

[0021] With reference to the first aspect, in some implementations of the first aspect, the method further includes a step of the first network device determining, based on the first channel matrix and at least one codebook set, at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook, wherein the first channel matrix is ​​determined based on one or more of a channel matrix determined based on an SRS measurement channel, a channel matrix determined based on a CSI-RS measurement channel, and a channel matrix determined based on a DMRS measurement channel.

[0022] With reference to the first aspect, in some implementations of the first aspect, the first network device determining the at least one codebook and a weighting factor matrix corresponding to the at least one codebook based on the first channel matrix and the at least one codebook set includes the first network device projecting the first channel matrix onto the at least one codebook set to obtain the at least one codebook and the weighting factor matrix corresponding to the at least one codebook that maximizes channel capacity and / or maximizes channel throughput.

[0023] Based on the above technical solution, the first network device can determine a first channel matrix according to one or more of the above channel matrices, and generate first information according to the first channel matrix. Correspondingly, the performance of the first beamforming matrix determined by the second network device based on the first information is better, so that the downlink transmission performance can be improved.

[0024] Referring to the first aspect, in some implementations of the first aspect, the at least one codebook set includes at least one of a first codebook set, a second codebook set, and a third codebook set, for example, the first codebook set is a spatial domain codebook set, the second codebook set is a frequency domain codebook set, and the third codebook set is an analog domain codebook set.

[0025] Referring to the first aspect, in some implementations of the first aspect, the first network device is a control device and the second network device is a radio frequency device, and the method further includes a step of the first network device sending information indicating at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook to a third network device, where the third network device and the second network device belong to different cells.

[0026] The third network device is a control device or a radio frequency device.

[0027] Based on the above technical solution, the first network device sends information indicating at least one codebook and a weighting factor matrix corresponding to the at least one codebook to the third network device, which is helpful to implement multi-cell coordinated transmission. For example, when the third network device is a radio frequency device, the third network device can determine a first beamforming matrix based on the information indicating at least one codebook and a weighting factor matrix corresponding to the at least one codebook, and determine a third beamforming matrix based on the first beamforming matrix. Thus, when the third network device performs beamforming on downlink transmission signals based on the third beamforming matrix, interference to users served by the second network device can be avoided.

[0028] Referring to the first aspect, in some implementations of the first aspect, the first network device is a radio frequency device and the second network device is a control device, and the method further includes a step of the first network device performing beamforming on the signal using a first beamforming matrix.

[0029] According to a second aspect, there is provided a transmission method, the method including: a step of receiving first information by a second network device from a first network device, the first information indicating at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook, the at least one codebook and the weighting coefficient matrix corresponding to the at least one codebook being used to determine a first beamforming matrix; and a step of the second network device determining, based on the first information, the at least one codebook and the weighting coefficient matrix corresponding to the at least one codebook.

[0030] Based on the above technical solution, the first network device sends first information indicating at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook to the second network device instead of sending a beamforming matrix, so that the amount of data sent by the first network device to the second network device can be reduced. For example, the first information can indicate at least one codebook by using a codebook index, that is, the first information can include an index of at least one codebook, and the data amount of the index of the at least one codebook is much less than the data amount of the entire beamforming matrix.

[0031] For example, the first network device is a control device and the second network device is a radio frequency device, or the first network device is a radio frequency device and the second network device is a control device. The radio frequency device has a baseband processing function. For example, the radio frequency device may be a BBL.

[0032] Referring to the second aspect, in some implementations of the second aspect, the first information indicates a column vector or a row vector included in at least one codebook.

[0033] Referring to the second aspect, in some implementations of the second aspect, the at least one codebook includes a first codebook, for example, the first codebook is a spatial domain codebook.

[0034] Referring to the second aspect, in some implementations of the second aspect, the at least one codebook includes a first codebook and a second codebook, for example, the first codebook is a spatial domain codebook and the second codebook is a frequency domain codebook.

[0035] Referring to the second aspect, in some implementations of the second aspect, the first beamforming matrix includes a first stage matrix and a second stage matrix, the at least one codebook includes a first codebook and a third codebook, a weighting coefficient matrix corresponding to the at least one codebook corresponds to the first codebook, the first codebook and the weighting coefficient matrix are used to determine the first stage matrix, and the third codebook is used to determine the second stage matrix.

[0036] For example, the first codebook is a spatial domain codebook and the third codebook is an analog domain codebook.

[0037] Based on the above technical solution, the first information sent by the first network device to the second network device further indicates a third codebook, so that the second network device can determine a second stage matrix according to the third codebook. Thus, the second network device can perform secondary beamforming for downlink transmission based on the second stage matrix, and a more accurate beam direction is realized.

[0038] Referring to the second aspect, in some implementations of the second aspect, the first beamforming matrix includes a first stage matrix and a second stage matrix, the at least one codebook includes a first codebook, a second codebook, and a third codebook, a weighting coefficient matrix corresponding to the at least one codebook corresponds to the first codebook and the second codebook, and the first codebook, the second codebook, and the weighting coefficient matrix are used to determine the first stage matrix, and the third codebook is used to determine the second stage matrix.

[0039] For example, the first codebook is a spatial domain codebook, the second codebook is a frequency domain codebook, and the third codebook is an analog domain codebook.

[0040] Based on the above technical solution, the first information sent by the first network device to the second network device further indicates a third codebook, so that the second network device can determine a second stage matrix according to the third codebook. Thus, the second network device can perform secondary beamforming for downlink transmission based on the second stage matrix, and a more accurate beam direction is realized.

[0041] Referring to the second aspect, in some implementations of the second aspect, the first network device is a radio frequency device, the second network device is a control device, and the method further includes a step of the second network device sending information indicating at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook to the fourth network device, where the fourth network device and the first network device belong to different cells.

[0042] The fourth network device is a control device or a radio frequency device.

[0043] Based on the above technical solution, the second network device sends information indicating at least one codebook and a weighting factor matrix corresponding to the at least one codebook to the fourth network device, which is helpful to implement multi-cell coordinated transmission. For example, when the fourth network device is a radio frequency device, the fourth network device can determine a first beamforming matrix based on the information indicating at least one codebook and a weighting factor matrix corresponding to the at least one codebook, and determine a fourth beamforming matrix based on the first beamforming matrix. Thus, when the fourth network device performs beamforming on downlink transmission information based on the fourth beamforming matrix, interference to users served by the first network device can be avoided.

[0044] Referring to the second aspect, in some implementations of the second aspect, the first network device is a control device and the second network device is a radio frequency device, and the method further includes a step of the second network device determining a first beamforming matrix based on the first information, and a step of the second network device performing beamforming on the signal using the first beamforming matrix.

[0045] According to a third aspect, a communication apparatus is provided. The communication apparatus includes a processing unit and a transceiver unit. The processing unit is configured to generate first information, the first information indicating at least one codebook and a weighting factor matrix corresponding to the at least one codebook, and the at least one codebook and the weighting factors corresponding to the at least one codebook are used to determine a first beamforming matrix. The transceiver unit is configured to transmit the first information to a second network device.

[0046] With reference to the third aspect, in some implementations of the third aspect, the first information indicates a column vector or a row vector included in at least one codebook.

[0047] With reference to the third aspect, in some implementations of the third aspect, the at least one codebook includes a first codebook.

[0048] Referring to the third aspect, in some implementations of the third aspect, the at least one codebook includes a first codebook and a second codebook.

[0049] Referring to the third aspect, in some implementations of the third aspect, the first beamforming matrix includes a first stage matrix and a second stage matrix, the at least one codebook includes a first codebook and a third codebook, a weighting coefficient matrix corresponding to the at least one codebook corresponds to the first codebook, the first codebook and the weighting coefficient matrix are used to determine the first stage matrix, and the third codebook is used to determine the second stage matrix.

[0050] Referring to the third aspect, in some implementations of the third aspect, the first beamforming matrix includes a first stage matrix and a second stage matrix, the at least one codebook includes a first codebook, a second codebook, and a third codebook, a weighting coefficient matrix corresponding to the at least one codebook corresponds to the first codebook and the second codebook, and the first codebook, the second codebook, and the weighting coefficient matrix are used to determine the first stage matrix, and the third codebook is used to determine the second stage matrix.

[0051] With reference to the third aspect, in some implementations of the third aspect, the processing unit is further configured to determine at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook based on a second beamforming matrix and at least one codebook set, wherein the second beamforming matrix is ​​determined based on one or more of a beamforming matrix determined based on an SRS measurement channel, a beamforming matrix determined based on a CSI-RS measurement channel, a beamforming matrix determined based on a DMRS measurement channel, and a static beamforming matrix.

[0052] Referring to the third aspect, in some implementations of the third aspect, the processing unit is specifically configured to project the second beamforming matrix onto the at least one codebook set to obtain at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook that maximizes channel capacity and / or maximizes channel throughput.

[0053] With reference to the third aspect, in some implementations of the third aspect, the processing unit is further configured to determine at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook based on the first channel matrix and the at least one codebook set, wherein the first channel matrix is ​​determined based on one or more of a channel matrix determined based on an SRS measurement channel, a channel matrix determined based on a CSI-RS measurement channel, and a channel matrix determined based on a DMRS measurement channel.

[0054] Referring to the third aspect, in some implementations of the third aspect, the processing unit is specifically configured to project the first channel matrix onto the at least one codebook set to obtain at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook that maximizes channel capacity and / or maximizes channel throughput.

[0055] Referring to the third aspect, in some implementations of the third aspect, the at least one codebook set includes at least one of a first codebook set, a second codebook set, and a third codebook set.

[0056] Referring to the third aspect, in some implementations of the third aspect, the first codebook, the second codebook, or the third codebook is one of the following codebooks: a spatial domain codebook, a frequency domain codebook, or an analog domain codebook.

[0057] Referring to the third aspect, in some implementations of the third aspect, the transceiver unit is further configured to send information indicating at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook to a third network device, wherein the third network device and the second network device belong to different cells.

[0058] With reference to the third aspect, in some implementations of the third aspect, the processing unit is further configured to perform beamforming on the signal using the first beamforming matrix.

[0059] According to a fourth aspect, a communication apparatus is provided. The communication apparatus includes a transceiver unit and a processing unit. The transceiver unit is configured to receive first information from a first network device, the first information indicating at least one codebook and a weighting factor matrix corresponding to the at least one codebook, and the at least one codebook and the weighting factor matrix corresponding to the at least one codebook are used to determine a first beamforming matrix. The processing unit is configured to determine the at least one codebook and the weighting factor matrix corresponding to the at least one codebook based on the first information.

[0060] With reference to the fourth aspect, in some implementations of the fourth aspect, the first information indicates a column vector or a row vector included in at least one codebook.

[0061] With reference to the fourth aspect, in some implementations of the fourth aspect, the at least one codebook includes a first codebook.

[0062] Referring to the fourth aspect, in some implementations of the fourth aspect, the at least one codebook includes a first codebook and a second codebook.

[0063] With reference to the fourth aspect, in some implementations of the fourth aspect, the first beamforming matrix includes a first stage matrix and a second stage matrix, the at least one codebook includes a first codebook and a third codebook, a weighting coefficient matrix corresponding to the at least one codebook corresponds to the first codebook, the first codebook and the weighting coefficient matrix are used to determine the first stage matrix, and the third codebook is used to determine the second stage matrix.

[0064] With reference to the fourth aspect, in some implementations of the fourth aspect, the first beamforming matrix includes a first stage matrix and a second stage matrix, the at least one codebook includes a first codebook, a second codebook, and a third codebook, a weighting coefficient matrix corresponding to the at least one codebook corresponds to the first codebook and the second codebook, and the first codebook, the second codebook, and the weighting coefficient matrix are used to determine the first stage matrix, and the third codebook is used to determine the second stage matrix.

[0065] Referring to the fourth aspect, in some implementations of the fourth aspect, the first codebook, the second codebook, or the third codebook is one of the following codebooks: a spatial domain codebook, a frequency domain codebook, or an analog domain codebook.

[0066] With reference to the fourth aspect, in some implementations of the fourth aspect, the transceiver unit is further configured to transmit the first information to the fourth network device, wherein the fourth network device and the first network device belong to different cells.

[0067] With reference to the fourth aspect, in some implementations of the fourth aspect, the processing unit is further configured to determine a first beamforming matrix based on the first information, and the processing unit is further configured to perform beamforming on the signal using the first beamforming matrix.

[0068] According to a fifth aspect, an apparatus is provided that includes a processor. The processor may be coupled to a memory and configured to execute instructions in the memory to perform the method of any one of the first aspect and possible implementations of the first aspect. Optionally, the apparatus further includes the memory. Optionally, the apparatus further includes a communication interface, and the processor is coupled to the communication interface.

[0069] In one implementation, the apparatus is a first network device. When the apparatus is a first network device, the communication interface may be a transceiver or an input / output interface.

[0070] In another implementation, the apparatus is a chip or chip system configured in the first network device. When the apparatus is a chip configured in the first network device, the communication interface may be an input / output interface. The chip system includes at least one chip and may further include another circuit structure and / or discrete devices.

[0071] Optionally, the transceiver may be a transceiver circuit. Optionally, the input / output interface may be an input / output circuit.

[0072] According to a sixth aspect, a communication device is provided, the device including a processor. The processor may be coupled to a memory and configured to execute instructions in the memory to implement the method of the second aspect and any one of the possible implementations of the second aspect. Optionally, the device further includes the memory. Optionally, the device further includes a communication interface, the processor being coupled to the communication interface.

[0073] In one implementation, the apparatus is a second network device. When the apparatus is a second network device, the communication interface may be a transceiver or an input / output interface.

[0074] In another implementation, the apparatus is a chip or chip system configured in the first network device. When the apparatus is a chip configured in the first network device, the communication interface may be an input / output interface. The chip system includes at least one chip and may further include another circuit structure and / or discrete devices.

[0075] Optionally, the transceiver may be a transceiver circuit. Optionally, the input / output interface may be an input / output circuit.

[0076] According to a seventh aspect, the present application provides a processor including an input circuit, an output circuit, and a processing circuit configured to receive a signal through the input circuit and to transmit a signal through the output circuit, such that the processor performs the method of the previous aspect.

[0077] In a specific implementation process, the processor may be a chip, the input circuit may be an input pin, the output circuit may be an output pin, and the processing circuit may be a transistor, a gate circuit, a trigger, various logic circuits, etc. The input signal received by the input circuit may be, for example, but not limited to, received and input by a receiver, and the signal output by the output circuit may be, for example, but not limited to, output to a transmitter and transmitted by the transmitter. In addition, the input circuit and the output circuit may be the same circuit, which separately functions as an input circuit and an output circuit at different times. The specific implementation of the processor and various circuits is not limited in this embodiment of the present application.

[0078] According to an eighth aspect, the present application provides a processing device including a communication interface and a processor. The communication interface is coupled to the processor. The communication interface is configured to input and / or output information. The information includes at least one of instructions or data. The processor is configured to execute a computer program, such that the processing device performs the method of the previous aspect.

[0079] According to a ninth aspect, the present application provides a processing device including a processor and a memory, the processor configured to read instructions stored in the memory, receive a signal using the receiver, and transmit a signal using the transmitter, such that the processing device performs the method of the previous aspect.

[0080] Optionally, there are one or more processors. If present, there may also be one or more memories.

[0081] Optionally, the memory may be integral to the processor, or the memory may be located separately from the processor.

[0082] In a specific implementation, the memory may be a non-transitory memory such as a read only memory (ROM). The memory and the processor may be integrated into one chip, or may be separately arranged on separate chips. The type of memory and the manner of arranging the memory and the processor are not limited in this embodiment of the present application.

[0083] It should be understood that the process of exchanging related information may, for example, be a process of transmitting the first information by a processor, and receiving the first information by a processor, and inputting the received first information into the processor. Specifically, the information output by the processor may be output to a transmitter, and the input information received by the processor may be from a receiver. The transmitter and receiver may be collectively referred to as a transceiver.

[0084] The device of the eighth and ninth aspects may be a chip or a chip system. The processor may be implemented by hardware or by software. When the processor is implemented by hardware, the processor may be a logic circuit, an integrated circuit, etc. When the processor is implemented by software, the processor may be a general-purpose processor and is implemented by reading software code stored in a memory. The memory may be integrated into the processor or may be located outside the processor and exist independently.

[0085] According to a tenth aspect, the present application provides a computer program product. The computer program product includes a computer program (sometimes called code or instructions) that, when executed, enables a computer to perform the method of the previous aspect.

[0086] According to an eleventh aspect, the present application provides a computer-readable storage medium. The computer-readable storage medium stores a computer program (sometimes called code or instructions). When the computer program is executed on a computer, the computer is enabled to perform the method of the previous aspect.

[0087] According to a twelfth aspect, the present application provides a system including the first network device and the second network device as previously described. [Brief description of the drawings]

[0088] [Figure 1] FIG. 1 is a schematic diagram of a system applicable to a method according to an embodiment of the present application. [Diagram 2] FIG. 2 is a schematic diagram of the structure of a network device according to an embodiment of the present application; [Diagram 3] 1 is a schematic flow chart of a method according to an embodiment of the present application. [Figure 4] FIG. 1 is a schematic diagram of a method according to an embodiment of the present application. [Diagram 5] 1 is a schematic block diagram of an apparatus according to an embodiment of the present application; [Figure 6] FIG. 1 is a schematic diagram of the structure of an apparatus according to an embodiment of the present application. [Figure 7] FIG. 1 is a schematic diagram of a chip system according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0089] Hereinafter, the technical solutions of the embodiments of the present application will be described with reference to the accompanying drawings.

[0090] The technical solutions of the embodiments of the present application may be applied to various communication systems, such as a long term evolution (LTE) system, a frequency division duplex (FDD) system, a time division duplex (TDD) system, a worldwide interoperability for microwave access (WiMAX) communication system, a fifth generation (5G) system, a new radio (NR) system, a sixth generation (6G) system, or a future communication system. The 5G mobile communication system in the present application includes a non-standalone (NSA) 5G mobile communication system or a standalone (SA) 5G mobile communication system. Alternatively, the communication system may be a public land mobile network (PLMN), a device-to-device (D2D) communication system, a machine-to-machine (M2M) communication system, an Internet of things (IoT) communication system, a vehicle to everything (V2X) communication system, an unmanned aerial vehicle (UAV) communication system, or another communication system.

[0091] In the description of this application, " / " represents an "or" relationship between related objects unless otherwise specified. For example, A / B can represent A or B. The term "and / or" in this application represents only the related relationship to describe related objects and represents that three relationships may exist. For example, A and / or B can represent the following three cases, namely, when only A exists, when both A and B exist, and when only B exists, and A and B may be singular or plural. In addition, in the description of this application, "plurality" means two or more unless otherwise specified. At least one of the following items or similar expressions refers to any combination of these items, including any combination of single items or multiple items. For example, at least one of a, b, or c can refer to a, b, c, a and b, a and c, b and c, or a, b, and c, and a, b, and c may be singular or plural.

[0092] In addition, in order to clearly describe the technical solutions of the embodiments of the present application, the embodiments of the present application use terms such as "first" and "second" to distinguish between the same or similar items having essentially the same function or purpose. Those skilled in the art can understand that terms such as "first" and "second" do not limit the quantity or execution order, and terms such as "first" and "second" do not indicate clear differences. In addition, in the embodiments of the present application, words such as "example" or "for example" are used to represent giving an example, illustration, or explanation. Any embodiment or technical solution described as "example" or "for example" in the embodiments of the present application should not be described as being preferred over another embodiment or design solution, or as having more advantages than another embodiment or design solution. Strictly speaking, the use of words such as "example" or "for example" is intended to present related concepts in a particular manner for ease of understanding.

[0093] In addition, the network architectures and service scenarios described in the embodiments of the present application are intended to more clearly explain the technical solutions of the embodiments of the present application, and do not constitute limitations on the technical solutions provided in the embodiments of the present application. As those skilled in the art can understand, with the evolution of network architectures and the emergence of new service scenarios, the technical solutions provided in the embodiments of the present application can also be applied to similar technical problems.

[0094] In order to facilitate understanding of the embodiments of the present application, the application scenario of the embodiments of the present application will first be described in detail with reference to FIG.

[0095] Figure 1 is a system architecture applicable to a method according to an embodiment of the present application. As shown in Figure 1, the system includes a first network device and a second network device. The first network device and the second network device are connected using a first interface. The first interface may be any one of the following interfaces: common public radio interface (CPRI), enhanced CPRI (eCPRI) interface, or an interface defined in the future to connect two network devices. For example, the first interface may be referred to as a fronthaul interface.

[0096] For example, the first network device is a control device, and the second network device is a radio frequency device. As shown in FIG. 1(a), the first network device is provided with a calculation module. The calculation module is configured to calculate a beamforming matrix, and the first network device can transmit the beamforming matrix to the second network device using the first interface. The second network device is provided with a beamforming module, and the beamforming module is configured to perform beamforming on the signal to be transmitted based on the beamforming matrix. In another example, the first network device is a radio frequency device, and the second network device is a control device. As shown in FIG. 1(b), the first network device is provided with a calculation module and a beamforming module. The calculation module is configured to calculate a beamforming matrix, and the beamforming module is configured to perform beamforming on the signal to be transmitted based on the beamforming matrix. In a multi-cell cooperation scenario, the first network device can transmit the beamforming matrix to the second network device using the first interface. Correspondingly, after receiving the beamforming matrix from the first network device, the second network device can send the beamforming matrix to the third network device, where the third network device is a radio frequency device or a control device, and the third network device and the first network device belong to different cells.

[0097] The control device can function as the primary device of the base station, providing a function of processing baseband signals, for example, providing a baseband high (BBH) function, and / or providing control and management of the functions of the devices of the base station. For example, in the downlink direction, the BBH may have one or more functions of coding, rate matching, scrambling, modulation, and layer mapping. In the uplink direction, the BBH may have one or more functions of decoding, rate de-matching, de-scrambling, demodulation, and channel estimation / equalization. For example, the control device may be a baseband unit (BU or BBU), a centralized unit (CU), a distributed unit (DU), etc.

[0098] In some deployments, the control device may include a CU and a DU, and the DU is connected to the radio frequency device using the first interface. Furthermore, the CU may use an architecture in which the control plane (CP) and the user plane (UP) are separated. In other words, the CU may include a CU-CP entity and a CU-UP entity.

[0099] The radio frequency device may function as a radio frequency module of a base station and may be configured to process intermediate frequency signals and / or radio frequency signals, or may be configured to receive and transmit radio signals. The radio frequency device may further be configured to provide a function to process some baseband signals, for example to provide a baseband low (BBL) function. For example, in the downlink direction, the BBL may have one or more functions of resource element mapping, digital beam forming (DBF), inverse fast Fourier transformation (IFFT) and cyclic prefix addition, analog beam forming (ABF), and analog to digital conversion. In the uplink direction, the BBL may have one or more functions of fast Fourier transformation (FFT) and cyclic prefix removal, analog beam forming, analog to digital conversion, digital beam forming, and resource element de-mapping. For example, the radio frequency device may be a radio unit (RU), a remote radio unit (RRU), an active antenna unit (AAU), etc.

[0100] As described above, the first network device can transmit a beamforming matrix to the second network device using the first interface. The dimension of the beamforming matrix may be the number of antennas × the number of subbands × the number of transport layers. Alternatively, when the number of antennas is 1, the dimension of the beamforming matrix may be the number of subbands × the number of transport layers, when the number of subbands is 1, the dimension of the beamforming matrix may be the number of antennas × the number of transmission layers, or when the number of transport layers is 1, the dimension of the beamforming matrix may be the number of antennas × the number of subbands. Therefore, when the number of antennas, the number of subbands, or the number of transport layers is large, a large amount of bandwidth is occupied when the beamforming matrix is ​​transmitted using the first interface.

[0101] In consideration of this, an embodiment of the present application provides a transmission method to reduce the amount of data exchanged between a first network device and a second network device.

[0102] In order to facilitate understanding of the embodiments of the present application, the following provides a brief explanation of terms used in the embodiments of the present application.

[0103] 1. Beamforming Technology: Beamforming technology is sometimes called precoding technology. A network device can determine a beamforming matrix that matches the channel state based on known or estimated channel information to process a signal to be transmitted, so that the signal to be transmitted after beamforming is performed matches the channel, and the signal receiving device obtains better signal reception quality, for example, a higher signal to interference plus noise ratio (SINR). Therefore, when beamforming technology is used, a transmitting device and multiple receiving devices can transmit signals on the same time-frequency resource, i.e., multiple user multiple input multiple output (MU-MIMO) is realized.

[0104] 2. Spatial domain vector: A spatial domain vector may also be called an angle vector, digital beam vector, spatial domain beam basis vector, spatial domain basis vector, etc. The elements in the spatial domain vector may represent the weights of radio frequency channels. Based on the weights of radio frequency channels represented by the elements in the spatial domain vector, the signals on the radio frequency channels may be linearly superimposed, resulting in the formation of a region with a strong signal in a particular direction in space. The dimension of the spatial domain vector is N trx x 1, N trx represents the number of radio frequency channels.

[0105] Optionally, the spatial domain vector is one of the following vectors: a discrete Fourier transform (DFT) vector, a conjugate transpose of a DFT vector, an oversampled DFT vector, and a conjugate transpose of an oversampled DFT vector. The DFT vector may be a vector in a DFT matrix, the conjugate transpose of a DFT vector may be a column vector in the conjugate transpose of a DFT matrix, and the oversampled DFT vector may be a vector in an oversampled DFT matrix.

[0106] In one possible design, the spatial domain vector may be a 2 dimensions (2D)-DFT vector v as specified in, for example, the type II codebook of the NR protocol technical specification (TS) 38.214 release 15 (R15). l,m In other words, the spatial domain vector may be a 2D-DFT vector or an oversampled 2D-DFT vector. For the sake of brevity, a detailed description of the 2D-DFT vector is omitted here.

[0107] 3. Frequency domain vector: A frequency domain vector is also called a frequency domain basis vector. A frequency domain vector may be a vector used to represent the change rule of a channel in the frequency domain, or a frequency domain vector may be a vector used to represent the frequency domain characteristics of a channel, or a frequency domain vector may be a vector used to resist the change of a channel in the frequency domain. Each frequency domain vector can represent one change rule. When a signal is transmitted through a wireless channel, the signal may reach a receiving antenna from a transmitting antenna through multiple paths. Multipath delays cause frequency selective fading, which corresponds to the change of the channel in the frequency domain. Separate frequency domain vectors can be used to represent the change rule of the channel in the frequency domain caused by delays on separate transmitting paths. The dimension of a frequency domain vector is N f x 1, N f represents the number of frequency domain units.

[0108] Optionally, the frequency domain vector is one of the following vectors: a DFT vector, a conjugate transpose of a DFT vector, an oversampled DFT vector, a conjugate transpose of an oversampled DFT vector, a discrete cosine transform (DCT) vector, a conjugate transpose of a DCT vector, an oversampled DCT vector, and a conjugate transpose of an oversampled DCT vector. For example, the frequency domain vector may be a DFT vector as specified in Type II of NR TS 38.214 R15.

[0109] 4. Analog Beam Vector: The elements in the analog beam vector can represent the weights of the antenna elements. Based on the antenna element weights represented by the elements in the analog beam vector, the signals of the antenna elements can be linearly superimposed, resulting in a region having a strong signal in a particular direction in space. Note that in the embodiment of the present application, the antenna elements are antenna elements connected to a phase shifter in the analog domain, and different antenna elements are connected to different phase shifters in the analog domain. The dimension of the space domain vector is N ant x 1, N ant represents the number of antenna elements.

[0110] Optionally, the analog domain beam vector is one of the following vectors: a DFT vector, a conjugate transpose of a DFT vector, an oversampled DFT vector, and a conjugate transpose of an oversampled DFT vector.

[0111] 5. Spatial domain codebooks and spatial domain codebook sets: The spatial domain codebook represents a spatial domain vector set including L spatial domain vectors, where L is a positive integer. It is understood that when the spatial domain codebook includes one spatial domain vector, the spatial domain codebook may also be referred to as a spatial domain vector. It is further understood that the spatial domain codebook may be represented in the form of a matrix. For example, if the spatial domain vector is a column vector, the L spatial domain vectors may be sequentially arranged from left to right to obtain a spatial domain codebook in matrix form, or the conjugate transposes of the L spatial domain vectors may be sequentially arranged from top to bottom to obtain a spatial domain codebook in matrix form. It is further understood that the spatial domain codebook may be represented in the form of a vector. For example, if the spatial domain vector is a column vector, the L spatial domain vectors may be sequentially arranged from top to bottom to obtain a spatial domain codebook in vector form.

[0112] A spatial domain codebook set represents a spatial domain vector set that includes L′ spatial domain vectors, where L′ is an integer greater than or equal to L. In one possible design, the spatial domain codebook set includes N trx number of spatial domain vectors (i.e., L'=N trx ), N trx Every other one of the spatial domain vectors may be orthogonal to each other, trx In another possible design, N trx The spatial domain vectors are then scaled by the oversampling factor O s Using (O s ×N trx ) spatial domain vectors. In this case, the spatial domain codebook set is s each subset may include N trx Each subset may contain N spatial domain vectors. trx Every other one of the spatial domain vectors may be orthogonal to one another.

[0113] The spatial domain codebook set may also refer to a set that includes X spatial domain codebooks, where X is a positive integer, each of which includes one or more of the L′ spatial domain vectors.

[0114] 6. Frequency domain codebooks and frequency domain codebook sets: The frequency domain codebook represents a frequency domain vector set including M frequency domain vectors, where M is a positive integer. It is understood that when the frequency domain codebook includes one frequency domain vector, the frequency domain codebook may also be referred to as a frequency domain vector. It is further understood that the frequency domain codebook may be expressed in the form of a matrix. For example, if the frequency domain vector is a column vector, the M frequency domain vectors may be sequentially arranged from left to right to obtain a frequency domain codebook in the form of a matrix, or the conjugate transposes of the M frequency domain vectors may be sequentially arranged from top to bottom to obtain a frequency domain codebook in the form of a matrix. It is further understood that the frequency domain codebook may be expressed in the form of a vector. For example, if the frequency domain vector is a column vector, the M frequency domain vectors may be sequentially arranged from top to bottom to obtain a frequency domain codebook in the form of a vector.

[0115] A frequency-domain codebook set represents a frequency-domain vector set that includes M′ frequency-domain vectors, where M′ is an integer greater than or equal to M. In one possible design, a frequency-domain codebook set includes N f space domain vectors (i.e., M'=N f ), N f Every other one of the N frequency domain vectors may be orthogonal to one another, f In another possible design, N f The frequency domain vectors are f Using (O f ×N f ) frequency domain vectors. In this case, the frequency domain codebook set is f each subset may include N f Each subset may contain N frequency domain vectors. f Every other one of the frequency domain vectors may be orthogonal to one another.

[0116] 7. Analog domain codebooks and analog domain codebook sets: The analog domain codebook represents an analog beam vector set including B analog beam vectors, where B is a positive integer. It is understood that when the analog domain codebook includes one analog beam vector, the analog domain codebook may also be referred to as an analog domain vector. It is further understood that the analog domain codebook may be represented in the form of a matrix. For example, if the analog beam vector is a column vector, the B analog beam vectors may be sequentially arranged from left to right to obtain the analog domain codebook in the form of a matrix, or the conjugate transposes of the B analog beam vectors may be sequentially arranged from left to right to obtain the analog domain codebook in the form of a matrix. It is further understood that the analog domain codebook may be represented in the form of a vector. For example, if the analog beam vector is a column vector, the B analog beam vectors may be sequentially arranged from top to bottom to obtain the analog domain codebook in the form of a vector.

[0117] An analog domain codebook set represents an analog beam vector set that includes B' analog beam vectors, where B' is an integer equal to or greater than B. In one possible design, the analog domain codebook set includes N ant analog beam vectors (i.e., B'=N ant ), N ant Every other one of the analog beam vectors may be orthogonal to each other, ant represents the number of antenna elements.

[0118] In the following, with reference to FIG. 2, a schematic diagram of the structures of a first network device and a second network device according to an embodiment of the present application is described.

[0119] In one possible implementation, the first network device is a control device and the second network device is a radio frequency device. The first network device may include a generating module configured to generate first information. The first information indicates at least one codebook and a weighting factor matrix corresponding to the at least one codebook, and the at least one codebook and the weighting factor matrix corresponding to the at least one codebook are used to determine a first beamforming matrix. Optionally, as shown in FIG. 2(a), the first network device may further include a calculation module and a quantization module. The calculation module is configured to calculate a second beamforming matrix or a first channel matrix. The quantization module is configured to determine the at least one codebook and the weighting factor matrix corresponding to the at least one codebook based on the second beamforming matrix or the first channel matrix. The at least one codebook and the weighting factor matrix corresponding to the at least one codebook are used to determine a first beamforming matrix. For a detailed description of the functions of the calculation module and the quantization module, please refer to the description of the method 300 below. The first network device may be further configured to transmit the first information to the second network device using the first interface. The second network device may include a reconstruction module and a beamforming module. The reconstruction module is configured to determine a first beamforming matrix based on the first information. The beamforming module is configured to perform beamforming on the signal to be transmitted based on the first beamforming matrix. For a detailed description of the functions of the reconstruction module and the beamforming module, please refer to the description of method 300 below.

[0120] The first network device and the second network device belong to the same cell or belong to different cells, which is not limited in this embodiment of the present application. The second beamforming matrix is ​​obtained by measuring a channel, and the first beamforming matrix is ​​determined based on the first information. The first beamforming matrix is ​​the same as or similar to the second beamforming matrix, or the first beamforming matrix is ​​used to reconstruct or approximate the second beamforming matrix.

[0121] For example, the generating module included in the first network device is configured to generate the first information based on the second information received from the network device #A, and the second information indicates at least one codebook and a weighting factor matrix corresponding to the at least one codebook. For example, the first network device generating the first information means that the first network device uses the second information as the first information as it is. As another example, the first network device generating the first information means that the first network device determines the at least one codebook and the weighting factor matrix corresponding to the at least one codebook based on the second information, and then determines the first information based on the at least one codebook and the weighting factor matrix corresponding to the at least one codebook. The network device #A is a control device or a radio frequency device.

[0122] As another example, the first network device is configured to generate the first information based on the second beamforming matrix or the first channel matrix. As shown in (a) of FIG. 2, the first network device may include a calculation module and a quantization module. The calculation module is configured to calculate the second beamforming matrix or the first channel matrix. The quantization module is configured to generate the first information based on the second beamforming matrix or the first channel matrix. For a detailed description of the functions of the calculation module and the quantization module, please refer to the description of the method 300 below.

[0123] Optionally, the first network device may further transmit the first information or the information indicating the at least one codebook and the weighting factor matrix corresponding to the at least one codebook to a third network device, where the third network device is a control device or a radio frequency device, and the third network device and the second network device belong to different cells.

[0124] In another possible implementation, the first network device is a radio frequency device, and the second network device is a control device. The first network device includes a module, for example a generating module, configured to generate first information. The first network device can transmit the first information to the second network device using the first interface. Correspondingly, after receiving the first information from the first network device, the second network device can transmit the first information or information indicating at least one codebook and a weighting factor matrix corresponding to the at least one codebook to the fourth network device. The fourth network device may be a radio frequency device or a control device, and the fourth network device and the first network device belong to different cells.

[0125] For example, the generating module included in the first network device is configured to generate the first information based on the second information received from the network device #A, and the second information indicates at least one codebook and a weighting factor matrix corresponding to the at least one codebook. For example, the first network device generating the first information means that the first network device uses the second information as the first information as it is. As another example, the first network device generating the first information means that the first network device determines the at least one codebook and the weighting factor matrix corresponding to the at least one codebook based on the second information, and then determines the first information based on the at least one codebook and the weighting factor matrix corresponding to the at least one codebook. The network device #A is a control device or a radio frequency device.

[0126] As another example, the first network device is configured to generate the first information based on the second beamforming matrix or the first channel matrix. As shown in (b) of FIG. 2, the first network device may include a calculation module, a quantization module, and a beamforming module. The calculation module is configured to calculate the second beamforming matrix or the first channel matrix. The beamforming module is configured to perform beamforming on the signal to be transmitted based on the second beamforming matrix. The quantization module is configured to generate the first information based on the second beamforming matrix or the first channel matrix.

[0127] Optionally, the first network device further includes a reconfiguration module. In a multi-cell cooperation scenario, the second network device can receive third information from the network device #B. The third information indicates at least one codebook and a weighting factor corresponding to the at least one codebook, and the at least one codebook and the weighting factor corresponding to the at least one codebook are used to determine a beamforming matrix #A. Furthermore, the second network device transmits information indicating the at least one codebook and the weighting factor corresponding to the at least one codebook to the first network device using the first interface. Correspondingly, the reconfiguration module included in the first network device is configured to determine a beamforming matrix #A based on the at least one codebook and the weighting factor corresponding to the at least one codebook. Furthermore, the calculation module included in the first network device is configured to calculate a second beamforming matrix based on the beamforming matrix #A, so that interference to a user served by the network device #B can be avoided when the second network device performs beamforming on a downlink transmission signal based on the second beamforming matrix. Network device #B may be a control device, and network device #B and the first network device belong to different cells.

[0128] The following describes a transmission method provided in an embodiment of the present application with reference to Fig. 3. Fig. 3 is a schematic flowchart of a transmission method according to an embodiment of the present application. The following describes in detail the steps included in the method 300.

[0129] S310: A first network device generates first information.

[0130] The first information indicates at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook, the at least one codebook and the weighting coefficient matrix corresponding to the at least one codebook are used to determine a first beamforming matrix, and the first beamforming matrix is ​​used to perform beamforming on the downlink transmission signal.

[0131] In one possible implementation, the at least one codebook includes a first codebook, and the weighting factor matrix corresponding to the at least one codebook includes a weighting factor matrix corresponding to the first codebook. In other words, the first information indicates the first codebook and the weighting factor matrix corresponding to the first codebook. The first codebook may be a spatial domain codebook. In the following, an example in which the first codebook is a spatial domain codebook is used for explanation. Alternatively, optionally, the first codebook may be another codebook with a different name or meaning, which is not limited in the present application.

[0132] For example, the spatial domain codebook may be indicated by using an index, ie, the first information includes an index of the spatial domain codebook.

[0133] As another example, the spatial domain codebook may be indicated by using a first bitmap. The number of bits included in the first bitmap or the length of the first bitmap may be the number of spatial domain codebooks included in the spatial domain codebook set, and each bit included in the first bitmap corresponds to one spatial domain codebook in the spatial domain codebook set. For example, if a bit indicates "0", it can be considered that the spatial domain codebook corresponding to the bit is not selected, or if a bit indicates "1", it can be considered that the spatial domain codebook corresponding to the bit is selected, in other words, the spatial domain codebook corresponding to the bit is the spatial domain codebook indicated by the first information.

[0134] As another example, the spatial domain codebook may be indicated by using an index of a spatial domain vector included in the spatial domain codebook, i.e., the first information includes the indexes of L spatial domain vectors included in the spatial domain codebook. In other words, the first information can indicate L spatial domain vectors, and the L spatial domain vectors can form the spatial domain codebook. It should be noted that the L spatial domain vectors included in the spatial domain codebook may be L row vectors in the spatial domain codebook, or may be L column vectors in the spatial domain codebook.

[0135] Optionally, if the L spatial domain vectors are L row vectors in the spatial domain codebook, the first information can further include N trx or, if the L spatial domain vectors are L column vectors in the spatial domain codebook, the first information further indicates N trx Specifies row vectors.

[0136] As another example, the spatial domain codebook may be indicated by using a second bitmap. The number of bits included in the second bitmap or the length of the second bitmap may be the number of spatial domain vectors included in the spatial domain codebook set, and each bit included in the second bitmap corresponds to one spatial domain vector in the spatial domain codebook set. For example, if a bit indicates "0", the spatial domain vector corresponding to the bit may be considered as not being selected, or if a bit indicates "1", the spatial domain vector corresponding to the bit may be considered as being selected, in other words, the spatial domain vector corresponding to the bit is the spatial domain vector included in the spatial domain codebook indicated by the first information.

[0137] For example, a weighting coefficient matrix corresponding to a spatial domain codebook may include weighting coefficients corresponding to L spatial domain vectors. For example, the weighting coefficient matrix may include L columns, and the L columns correspond one-to-one with the L spatial domain vectors, or the weighting coefficient matrix may include L rows, and the L rows correspond one-to-one with the L spatial domain vectors. Optionally, the weighting coefficient matrix corresponding to a spatial domain codebook may refer to a wideband amplitude coefficient matrix. In addition, the weighting coefficient matrix corresponding to a spatial domain codebook may further include a subband coefficient matrix, and each subband coefficient included in the subband coefficient matrix includes a subband amplitude coefficient and a subband phase coefficient. For example, if the weighting coefficient matrix corresponding to a spatial domain codebook includes a wideband amplitude coefficient matrix, a subband amplitude coefficient matrix, and a subband phase coefficient matrix, the weighting coefficient matrix corresponding to a spatial domain codebook may be [a0a1...a L-1 ][b0b1...b L-1 ] T can be expressed as [a0a1...a L-1 ] represents the broadband amplitude coefficient matrix, and [b0b1...b L-1 ] T is the subband coefficient matrix [b0b1...b L-1 ], and b0 to b L-1 are the subband amplitude coefficients α0 to α L-1 and the subband phase coefficients φ0 to φ L-1 and the wideband amplitude coefficient and the spatial domain codebook are used to determine a first beamforming matrix corresponding to the wideband, and the wideband amplitude coefficient, the subband coefficient, and the spatial domain codebook are used to determine a first beamforming matrix corresponding to each subband included in the wideband. The first beamforming matrix corresponding to the wideband is used to perform beamforming on signals transmitted on one or more subbands included in the wideband. When the first beamforming matrix corresponding to each subband included in the wideband is determined, the first beamforming matrix corresponding to the subband is used to perform beamforming on signals transmitted on the subband.

[0138] For example, the weighting coefficient matrix corresponding to the spatial domain codebook may be ordered in a normalized manner.

[0139] Assuming that the weight coefficient matrix includes L rows of coefficients corresponding to L spatial domain vectors, the first network device can perform modulo operations on the L rows of coefficients separately to determine the row of coefficients with the maximum modulus. Furthermore, the first network device normalizes the row of coefficients with the maximum modulus, calculates the relative values ​​of the remaining (L-1) rows of coefficients to the row of coefficients with the maximum modulus, and uses the quantization information to indicate the relative values ​​of the (L-1) rows of coefficients to the row of coefficients with the maximum modulus. For the row of coefficients with the maximum modulus, the position of the row of coefficients with the maximum modulus can be indicated, for example, which row of coefficients with the maximum modulus is the row of the L rows of coefficients.

[0140] It should be understood that this is just one possible implementation of indicating the weighting factor matrix in a normalized manner and should not constitute any limitation to the present application. For example, the first network device may directly indicate the index of the quantized value of each weighting factor in the weighting factor matrix, or may indicate each weighting factor in the weighting factor matrix in a differential manner.

[0141] It should be noted that in this embodiment of the present application, the weighting factor corresponding to the spatial domain codebook is expressed as a weighting factor matrix, which is used only as an example and not a limitation. The weighting factor corresponding to the spatial domain codebook may be expressed in the form of a vector, an array, etc.

[0142] In another possible implementation, the at least one codebook includes a first codebook and a second codebook, and the weighting factor matrix corresponding to the at least one codebook includes a weighting factor matrix corresponding to both the first codebook and the second codebook. In other words, the first information indicates the first codebook, the second codebook, and the weighting factor matrix corresponding to the first codebook and the second codebook. Each weighting factor included in the weighting factor matrix corresponds to one vector in the first codebook and one vector in the second codebook, and different weighting factors correspond to different vectors in the first codebook and / or different vectors in the second codebook. The first codebook may be a spatial domain codebook, and the second codebook may be a frequency domain codebook. In the following, an example in which the first codebook is a spatial domain codebook and the second codebook is a frequency domain codebook is used for description. Alternatively, optionally, the first codebook and / or the second codebook may be different codebooks with different names or meanings, which is not a limitation of this application.

[0143] For example, the spatial domain codebook and the frequency domain codebook may be indicated by using indexes, ie, the first information includes an index of the spatial domain codebook and an index of the frequency domain codebook.

[0144] As another example, the spatial domain codebook and the frequency domain codebook may be indicated using a first bitmap and a third bitmap. For the description of the first bitmap, please refer to the above description. The number of bits included in the third bitmap or the length of the third bitmap may be the number of frequency domain codebooks included in the frequency domain codebook set, and each bit included in the third bitmap corresponds to one frequency domain codebook in the frequency domain codebook set. For example, if a bit indicates "0", it can be considered that the frequency domain codebook corresponding to the bit is not selected, or if a bit indicates "1", it can be considered that the frequency domain codebook corresponding to the bit is selected, in other words, the frequency domain codebook corresponding to the bit is the frequency domain codebook indicated by the first information.

[0145] As another example, the spatial domain codebook may be indicated by using an index of a spatial domain vector included in the spatial domain codebook, and the frequency domain codebook may also be indicated by using an index of a frequency domain vector included in the frequency domain codebook. Specifically, the first information includes an index of L spatial domain vectors included in the spatial domain codebook and an index of M frequency domain vectors included in the frequency domain codebook. In other words, the first information can indicate L spatial domain vectors and M frequency domain vectors, the L spatial domain vectors can form a spatial domain codebook, and the M frequency domain vectors can form a frequency domain codebook. It should be noted that the L spatial domain vectors included in the spatial domain codebook may be L row vectors in the spatial domain codebook or L column vectors in the spatial domain codebook. The M frequency domain vectors included in the frequency domain codebook may be M row vectors in the frequency domain codebook or M column vectors in the frequency domain codebook.

[0146] Optionally, if the M frequency domain vectors are M row vectors in a frequency domain codebook, the first information can further include N f or if the M frequency domain vectors are M column vectors in a frequency domain codebook, the first information further indicates N f Specifies row vectors.

[0147] As another example, the spatial domain codebook and the frequency domain codebook may be indicated using a second bitmap and a fourth bitmap. For the description of the second bitmap, please refer to the above description. The number of bits included in the fourth bitmap or the length of the fourth bitmap may be the number of frequency domain vectors included in the frequency domain codebook set, and each bit included in the fourth bitmap corresponds to one frequency domain vector in the frequency domain codebook set. For example, if a bit indicates "0", it can be considered that the frequency domain codebook corresponding to the bit is not selected, or if a bit indicates "1", it can be considered that the frequency domain codebook corresponding to the bit is selected, in other words, the frequency domain codebook corresponding to the bit is the frequency domain codebook indicated by the first information.

[0148] For example, the weighting factor matrices corresponding to the spatial domain codebook and the frequency domain codebook may be ordered in a normalized manner.

[0149] For example, the first network device can determine the weight coefficient having the largest amplitude (e.g., denoted as the maximum coefficient) from the weight coefficient matrix and indicate the position of the largest coefficient in the weight coefficient matrix (e.g., the row serial number and column serial number of the largest coefficient in the weight coefficient matrix).The first network device can then further indicate the relative value of the weight coefficient having the largest amplitude (e.g., denoted as the maximum coefficient in the row) in each row of the weight coefficient matrix to the aforementioned maximum coefficient, and the relative value of another weight coefficient in each row to the largest coefficient in the same row, or the first network device can further indicate the relative value of the weight coefficient having the largest amplitude (e.g., denoted as the maximum coefficient in the column) in each column of the weight coefficient matrix to the aforementioned maximum coefficient, and the relative value of another weight coefficient in each column to the largest coefficient in the same column.

[0150] As another example, the first network device can determine a weighting factor having a maximum amplitude from the weighting factor matrix (i.e., the aforementioned maximum coefficient) and indicate the position of the maximum coefficient in the weighting factor matrix (e.g., the row and column serial numbers of the maximum coefficient in the weighting factor matrix). The first network device can then further indicate the relative value of another weighting factor in the weighting factor matrix relative to the maximum coefficient.

[0151] It should be understood that this is just one possible implementation of indicating the weighting factor matrix in a normalized manner and should not constitute any limitation to the present application. For example, the first network device may directly indicate the index of the quantized value of each weighting factor in the weighting factor matrix, or may indicate each weighting factor in the weighting factor matrix in a differential manner.

[0152] It should be noted that in this embodiment of the present application, the weighting factors corresponding to the spatial domain codebook and the frequency domain codebook are expressed as a weighting factor matrix, which is only an example and not a limitation. The weighting factors corresponding to the spatial domain codebook and the frequency domain codebook may be expressed in the form of a vector, an array, etc.

[0153] The correspondence between each weighting factor in the weighting factor matrix and each of the spatial domain vectors in the spatial domain codebook and the frequency domain vectors in the frequency domain codebook may be indicated by using a bitmap, for example, the bitmap includes (L×M) bits, where the weighting factor indicated by the (l×m)th bit corresponds to the lth spatial domain vector in the spatial domain codebook and the mth frequency domain vector in the frequency domain codebook, where l is an integer greater than 0 and less than or equal to L, and m is an integer greater than 0 and less than or equal to M.

[0154] In yet another possible implementation, the at least one codebook includes a first codebook and a third codebook, and the weighting factor matrix corresponding to the at least one codebook includes a weighting factor matrix corresponding to the first codebook. In other words, the first information indicates the first codebook and the third codebook, and also indicates a weighting factor matrix corresponding to the first codebook. The first codebook and the weighting factor matrix are used to determine a first stage matrix included in the first beamforming matrix, and the third codebook is used to determine a second stage matrix included in the first beamforming matrix. The first stage matrix and the second stage matrix together perform beamforming for downlink transmission. For example, the first stage matrix is ​​used for digital beamforming for downlink transmission, and the second stage matrix is ​​used for analog beamforming for downlink transmission signals. The first codebook may be a spatial domain codebook, and the third codebook may be an analog domain codebook. In the following, an example is used for explanation, in which the first codebook is a spatial domain codebook and the third codebook is an analog domain codebook. Alternatively, optionally, the first codebook and / or the third codebook can be other codebooks with different names or meanings, which is not limited in this application.

[0155] For the indication method of the spatial domain codebook and the weighting coefficient matrix, please refer to the above description.

[0156] For example, the analog domain codebook may be indicated by using an index, ie, the first information includes an index of the analog domain codebook.

[0157] As another example, the analog domain codebook may be indicated using a fifth bitmap. The number of bits included in the fifth bitmap or the length of the fifth bitmap may be the number of analog domain codebooks included in the analog domain codebook set, and each bit included in the fifth bitmap corresponds to one analog domain codebook in the analog domain codebook set. For example, if a bit indicates "0", it can be considered that the analog domain codebook corresponding to the bit is not selected, or if a bit indicates "1", it can be considered that the analog domain codebook corresponding to the bit is selected, in other words, the analog domain codebook corresponding to the bit is the analog domain codebook indicated by the first information.

[0158] As another example, the analog domain codebook may be indicated by using an index of an analog domain vector included in the analog domain codebook, i.e., the first information includes the indexes of B analog domain vectors included in the analog domain codebook. In other words, the first information can indicate B analog domain vectors, and the B analog domain vectors can form the analog domain codebook. It should be noted that the B analog domain vectors included in the analog domain codebook may be B row vectors in the analog domain codebook or B column vectors in the analog domain codebook.

[0159] Optionally, if the B analog domain vectors are B row vectors in the analog domain codebook, the first information may further include N antor if the B spatial domain vectors are B column vectors in the analog domain codebook, the first information further indicates N ant Specifies row vectors.

[0160] As another example, the analog domain codebook may be indicated using a sixth bitmap. The number of bits included in the sixth bitmap or the length of the sixth bitmap may be the number of analog domain vectors included in the analog domain codebook set, and each bit included in the sixth bitmap corresponds to one analog domain vector in the analog domain codebook set. For example, if a bit indicates "0", the analog domain vector corresponding to the bit may be considered as not being selected, or if a bit indicates "1", the analog domain vector corresponding to the bit may be considered as being selected, in other words, the analog domain vector corresponding to the bit is the analog domain vector included in the analog domain codebook indicated by the first information.

[0161] In yet another possible implementation, the at least one codebook includes a first codebook, a second codebook, and a third codebook, and the weighting factor matrix corresponding to the at least one codebook includes a weighting factor matrix corresponding to both the first codebook and the second codebook. In other words, the first information indicates the first codebook, the second codebook, and the third codebook, and also indicates weighting factor matrices corresponding to the first codebook and the second codebook. The first codebook, the second codebook, and the weighting factor matrix are used to determine a first stage matrix included in the first beamforming matrix, and the third codebook is used to determine a second stage matrix included in the first beamforming matrix. The first codebook may be a spatial domain codebook, the second codebook may be a frequency domain codebook, and the third codebook may be an analog domain codebook. In the following, an example is used for explanation, in which the first codebook is a spatial domain codebook, the second codebook is a frequency domain codebook, and the third codebook is an analog domain codebook. Alternatively, optionally, the first codebook, the second codebook, and / or the third codebook may be different codebooks with different names or meanings, which is not limited in this application.

[0162] For the indication methods of the spatial domain codebook, the frequency domain codebook, the analog domain codebook, and the weighting coefficient matrix, please refer to the above description.

[0163] The manner in which the first network device generates the first information is not limited to this embodiment of the present application.

[0164] In one possible implementation, the first network device generates the first information based on a second beamforming matrix. The second beamforming matrix is ​​any one of the following matrices: a beamforming matrix determined based on an SRS measurement channel (denoted as an SRS beamforming matrix), a beamforming matrix determined based on a CSI-RS measurement channel (denoted as a PMI beamforming matrix), a beamforming matrix determined based on a DMRS measurement channel (denoted as a DMRS beamforming matrix), and a static beamforming matrix. Alternatively, the second beamforming matrix is ​​determined based on multiple matrices among the following matrices: an SRS beamforming matrix, a PMI beamforming matrix, a DMRS beamforming matrix, and a static beamforming matrix. For example, the second beamforming matrix may be obtained by averaging the aforementioned multiple matrices, or the second beamforming matrix may be obtained by summing the aforementioned multiple matrices.

[0165] For example, the first network device projects the second beamforming matrix onto the at least one codebook set to obtain at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook that maximizes channel capacity and / or maximizes channel throughput. The at least one codebook set may include at least one of a spatial domain codebook set, a frequency domain codebook set, and an analog domain codebook set.

[0166] In the following, an example in which the second beamforming matrix is ​​an SRS beamforming matrix is ​​used to describe a manner in which the first network device generates the first information based on the second beamforming matrix.

[0167] Method 1: The first network device projects the SRS beamforming matrix onto the spatial domain codebook set to obtain a spatial domain codebook and a weighting factor matrix corresponding to the spatial domain codebook that maximizes channel capacity and / or maximizes channel throughput. The dimension of the spatial domain codebook may be preset, in other words, the number L of spatial domain vectors included in the spatial domain codebook may be preset. For example, the number of spatial domain vectors may be preset based on the number of radio frequency channels. For example, the number L of spatial domain vectors is half the number of radio frequency channels. For example, when the number L of spatial domain vectors is preset, the spatial domain codebook that maximizes channel capacity and / or maximizes channel throughput can be considered to include the first L spatial domain vectors that are most correlated when the SRS beamforming matrix is ​​projected onto the spatial domain codebook set.

[0168] The following describes in detail a specific process in which the first network device determines the L spatial domain vectors and weighting coefficient matrix included in the spatial domain codebook.

[0169] As mentioned above, the spatial domain codebook set is N trx number of spatial domain vectors, the dimension of which is N trx × 1, and the matrix V S The dimension of is N trx ×N trx The first network device is

number

number

[0170] Furthermore, the first network device generates first information based on the L spatial domain vectors and the weighting factor matrix.

[0171] Method 2: The first network device projects the SRS beamforming matrix onto the spatial domain codebook set and the frequency domain codebook set to obtain a spatial domain codebook, a frequency domain codebook, and a weighting coefficient matrix corresponding to the spatial domain codebook and the frequency domain codebook that maximizes channel capacity and / or maximizes channel throughput. The dimension of the spatial domain codebook may be preset, in other words, the number L of spatial domain vectors included in the spatial domain codebook may be preset. The dimension of the frequency domain codebook may be preset, in other words, the number M of frequency domain vectors included in the frequency domain codebook may be preset. For example, the number of frequency domain vectors may be preset based on the number of frequency domain units. For example, the number L of frequency domain vectors is half the number of frequency domain units. For example, if the number of spatial domain vectors L and the number of frequency domain vectors M are preset, a spatial domain codebook that maximizes channel capacity and / or maximizes channel throughput can be considered to include the first L spatial domain vectors that are most correlated when an SRS beamforming matrix is ​​projected onto the spatial domain codebook set, and a frequency domain codebook that maximizes channel capacity and / or maximizes channel throughput can be considered to include the first M frequency domain vectors that are most correlated when an SRS beamforming matrix is ​​projected onto the frequency domain codebook set.

[0172] The following describes in detail a specific process in which the first network device determines the L space domain vectors included in the space domain codebook, the M frequency domain vectors included in the frequency domain codebook, and the weighting coefficient matrix.

[0173] As mentioned above, the matrix V S The dimension of is N trx ×N trx The frequency domain codebook set is N f number of frequency domain vectors, the dimension of the frequency domain vector being N f× 1, and the matrix V F The dimension of is N f ×N f The first network device is

number

number

[0174] Furthermore, the first network device generates first information based on the L spatial domain vectors, the M frequency domain vectors, and the weighting coefficient matrix.

[0175] Method 3: The first network device projects the SRS beamforming matrix onto the analog domain codebook set and the spatial domain codebook set to obtain a spatial domain codebook, a weighting factor matrix, and an analog domain codebook that maximizes channel capacity and / or maximizes channel throughput. The dimension of the analog domain codebook may be preset, in other words, the number B of analog domain vectors included in the analog domain codebook is preset. For example, the number of analog domain vectors may be preset based on the number of antenna elements. For example, the number B of analog domain vectors is half the number of antenna elements. For example, the analog domain codebook that maximizes channel capacity and / or maximizes channel throughput can be considered to include the first B analog domain vectors that are most correlated when the SRS beamforming matrix is ​​projected onto the analog domain codebook set.

[0176] The following describes in detail the process in which the first network device determines the B analog domain vectors contained in the analog domain codebook, the L spatial domain vectors contained in the spatial domain codebook, and the weighting coefficient matrix.

[0177] As mentioned above, the matrix V S The dimension of is N trx ×N trx The analog domain codebook set is N ant The analog domain vector may include N ant × 1, and the matrix V M The dimension of is N ant ×N ant The first network device is

number

number

[0178] Furthermore, the first network device

number

number

[0179] Furthermore, the first network device generates first information based on the L spatial domain vectors, the B analog domain vectors, and the weighting coefficient matrix.

[0180] Method 4: The first network device projects the SRS beamforming matrix onto the analog domain codebook set, the spatial domain codebook set, and the frequency domain codebook set to obtain a spatial domain codebook, a frequency domain codebook, a weighting coefficient matrix, and an analog domain codebook that maximizes channel capacity and / or maximizes channel throughput.

[0181] The following describes in detail the process by which the first network device determines the B analog domain vectors contained in the analog domain codebook, the L spatial domain vectors contained in the spatial domain codebook, and the M frequency domain vectors contained in the frequency domain codebook, as well as the weighting coefficient matrix.

[0182] As mentioned above, the matrix V S The dimension of is N trx ×N trx and the matrix V F The dimension of is N f ×N f and the matrix V M The dimension of is N ant ×N ant The first network device is

number

[0183] Furthermore, the first network device

number

[0184] Furthermore, the first network device generates first information based on the L spatial domain vectors, the M frequency domain vectors, the weighting coefficient matrix, and the B analog domain vectors.

[0185] It should be understood that the manner in which the first network device determines the first information based on the PMI beamforming matrix, the DMRS beamforming rectangle, or the static beamforming matrix is ​​the same as or similar to the manner in which the first network device determines the first information based on the SRS beamforming matrix. For the sake of brevity, details are not described in this embodiment of the present application.

[0186] In another possible implementation, the first network device generates the first information based on a first channel matrix. The first channel matrix may be any one of the following channel matrices: a channel matrix obtained based on an SRS measurement channel, a channel matrix obtained based on a CSI-RS measurement channel, and a channel matrix obtained based on a DMRS measurement channel. Alternatively, the first channel matrix is ​​determined based on multiple channel matrices among the following channel matrices: a channel matrix obtained based on an SRS measurement channel, a channel matrix obtained based on a CSI-RS measurement channel, and a channel matrix obtained based on a DMRS measurement channel. For example, the first channel matrix may be obtained by averaging multiple matrices, or the first channel matrix may be obtained by summing multiple matrices.

[0187] The channel matrix is ​​a form of channel information, and the channel information may be information used to represent a channel. The channel matrix may be used to determine a beamforming matrix. For example, a singular value decomposition (SVD) may be performed on the channel matrix to obtain the beamforming matrix.

[0188] For example, the first network device projects the first channel matrix onto at least one codebook set to obtain at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook that maximizes channel capacity and / or maximizes channel throughput. The at least one codebook set may include at least one of a spatial domain codebook set, a frequency domain codebook set, and an analog domain codebook set.

[0189] The following describes how the first network device generates the first information.

[0190] Method 1: The first network device projects the first channel matrix onto the spatial domain codebook set to obtain a spatial domain codebook and a weighting factor matrix corresponding to the spatial domain codebook that maximizes channel capacity and / or maximizes channel throughput. As described above, the spatial domain codebook that maximizes channel capacity and / or maximizes channel throughput includes the first L spatial domain vectors that are most correlated when the first channel matrix is ​​projected onto the spatial domain codebook set.

[0191] The following describes in detail a specific process in which the first network device determines the L spatial domain vectors and weighting coefficient matrix included in the spatial domain codebook.

[0192] As mentioned above, the matrix V S The dimension of is N trx ×N trx The first network device is

number

[0193] Furthermore, the first network device generates first information based on the L spatial domain vectors and the weighting factor matrix.

[0194] Method 2: The first network device projects the first channel matrix onto the spatial domain codebook set and the frequency domain codebook set to obtain a spatial domain codebook, a frequency domain codebook, and a first weighting factor matrix corresponding to the spatial domain codebook and the frequency domain codebook that maximizes channel capacity and / or maximizes channel throughput. As described above, the spatial domain codebook that maximizes channel capacity and / or maximizes channel throughput includes the first L spatial domain vectors that are most correlated when the first channel matrix is ​​projected onto the spatial domain codebook set, and the frequency domain codebook that maximizes channel capacity and / or maximizes channel throughput includes the first M frequency domain vectors that are most correlated when the first channel matrix is ​​projected onto the frequency domain codebook set.

[0195] The following describes in detail a specific process in which the first network device determines the L space domain vectors included in the space domain codebook, the M frequency domain vectors included in the frequency domain codebook, and the weighting coefficient matrix.

[0196] As mentioned above, the matrix V S The dimension of is N trx ×N trx and the matrix V F The dimension of is N f ×N f The first network device is

number

[0197] Furthermore, the first network device generates first information based on the L spatial domain vectors, the M frequency domain vectors, and the weighting coefficient matrix.

[0198] Method 3: The first network device projects the first channel matrix onto the analog domain codebook set and the spatial domain codebook set to obtain a spatial domain codebook, a weighting factor matrix, and an analog domain codebook that maximizes channel capacity and / or maximizes channel throughput. The dimension of the analog domain codebook may be preset, in other words, the number B of analog domain vectors included in the analog domain codebook is preset. For example, the analog domain codebook that maximizes channel capacity and / or maximizes channel throughput can be considered to include the first B analog domain vectors that are most correlated when the first channel matrix is ​​projected onto the analog domain codebook set.

[0199] The following describes in detail the process in which the first network device determines the B analog domain vectors contained in the analog domain codebook, the L spatial domain vectors contained in the spatial domain codebook, and the weighting coefficient matrix.

[0200] As mentioned above, the matrix V S The dimension of is N trx ×N trx and the matrix V M The dimension of is N ant ×N ant The first network device is

number

[0201] Furthermore, the first network device

number

number

[0202] Furthermore, the first network device generates first information based on the L spatial domain vectors, the B analog domain vectors, and the weighting coefficient matrix.

[0203] Method 4: The first network device projects the first channel matrix onto an analog domain codebook set, a spatial domain codebook set, and a frequency domain codebook set to obtain a spatial domain codebook, a frequency domain codebook, a weighting factor matrix, and an analog domain codebook that maximizes channel capacity and / or maximizes channel throughput.

[0204] The following describes in detail the process by which the first network device determines the B analog domain vectors contained in the analog domain codebook, the L spatial domain vectors contained in the spatial domain codebook, and the M frequency domain vectors contained in the frequency domain codebook, as well as the weighting coefficient matrix.

[0205] As mentioned above, the matrix V S The dimension of is N trx ×N trx and the matrix V F The dimension of is N f ×N f and the matrix V M The dimension of is N ant ×N ant The first network device is

number

[0206] Furthermore, the first network device

number

[0207] Furthermore, the first network device generates first information based on the L spatial domain vectors, the M frequency domain vectors, the weighting coefficient matrix, and the B analog domain vectors.

[0208] S320: The first network device transmits the first information to the second network device. Correspondingly, in S320, the second network device receives the first information from the first network device.

[0209] Please refer to the description of Fig. 2 above. If the first network device is a control device and the second network device is a radio frequency device, the second network device uses a reconstruction module to determine a first beamforming matrix after receiving the first information. In other words, the method 300 may further include S330.

[0210] S330: The second network device determines, based on the first information, at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook.

[0211] After receiving the first information from the first network device, the second network device can determine at least one codebook and a weighting coefficient matrix of the at least one codebook based on the first information. Specifically, the second network device determines at least one codebook based on the at least one codebook set and the first information. For example, if the first information includes an index of a spatial domain codebook, the second network device determines a spatial domain codebook from the spatial domain codebook set based on the index of the spatial domain codebook. As another example, if the first information includes an index of L spatial domain vectors, the second network device determines L spatial domain vectors from the spatial domain codebook set based on the index of the L spatial domain vectors, and then determines a spatial domain codebook based on the L spatial domain vectors. For example, the second network device arranges the L spatial domain vectors from left to right to configure a spatial domain codebook. As another example, if the first information further includes an index of a frequency domain codebook, the second network device determines a frequency domain codebook from the frequency domain codebook set based on the index of the frequency domain codebook. As another example, when the first information further includes an index of an analog domain codebook, the second network device determines an analog domain codebook from the analog domain codebook set based on the index of the analog domain codebook.

[0212] Optionally, when the first network device is a control device and the second network device is a radio frequency device, the second network device can determine a first beamforming matrix based on the at least one codebook and the weighting factor matrix corresponding to the at least one codebook after determining the at least one codebook and the weighting factor corresponding to the at least one codebook, and can perform beamforming on the signal based on the first beamforming matrix.

[0213] For example, when the at least one codebook includes a spatial domain codebook and a weighting factor matrix corresponding to the spatial domain codebook, and the first information is determined based on the second beamforming matrix, the second network device can directly determine the first beamforming matrix based on the spatial domain codebook and the weighting factor matrix corresponding to the spatial domain codebook.

number

number

number

[0214] When the first information is determined based on the first channel matrix, the second network device can determine the second channel matrix based on the spatial domain codebook and the weighting factor matrix corresponding to the spatial domain codebook. S W c =H’ Using H ’ can be determined, and H ’ where m represents the second channel matrix. The second network device then determines a first beamforming matrix based on the second channel matrix. For example, the second network device obtains the first beamforming matrix by performing singular value decomposition (SVD) on the second channel matrix.

[0215] For example, when the at least one codebook includes a spatial domain codebook, a frequency domain codebook, and a weighting factor matrix, and the first information is determined based on the second beamforming matrix, the second network device can directly determine the first beamforming matrix based on the spatial domain codebook, the frequency domain codebook, and the weighting factor matrix.

number

number

number

number

[0216] When the first information is determined based on the first channel matrix, the second network device can determine the second channel matrix based on the spatial domain codebook, the frequency domain codebook, and the weighting coefficient matrix. For example, the second network device

number

[0217] For example, when the at least one codebook includes a spatial domain codebook, a weighting coefficient matrix corresponding to the spatial domain codebook, and an analog domain codebook, and the first information is determined based on a second beamforming matrix, the second network device can directly determine the first-stage matrix based on the spatial domain codebook and the weighting coefficient matrix corresponding to the spatial domain codebook, and directly use the analog domain codebook as the second-stage matrix.

[0218] When the first information is determined based on the first channel matrix, the second network device can directly use the analog domain codebook as the second stage matrix, and can determine the second channel matrix based on the spatial domain codebook and the weighting coefficient matrix. For example, the second network device can S W c =H ’ Using H ’ The second network device may then determine a first stage matrix based on the second channel matrix. For example, the second network device may perform SVD on the second channel matrix to obtain the first stage matrix.

[0219] For example, when the at least one codebook includes a spatial domain codebook, a frequency domain codebook, a weighting coefficient matrix corresponding to the spatial domain codebook and the frequency domain codebook, and an analog domain codebook, and the first information is determined based on a second beamforming matrix, the second network device can directly determine the first-stage matrix based on the spatial domain codebook, the frequency domain codebook, and the weighting coefficient matrix corresponding to the spatial domain codebook and the frequency domain codebook, and directly use the analog domain codebook as the second-stage matrix.

[0220] When the first information is determined based on the first channel matrix, the second network device can directly use the analog domain codebook as the second stage matrix, and can determine the second channel matrix based on the spatial domain codebook, the frequency domain codebook, and the weighting coefficient matrix. For example, the second network device

number

[0221] In this embodiment of the present application, the first network device transmits first information indicating at least one codebook and a weighting coefficient matrix corresponding to the at least one codebook to the second network device instead of transmitting a beamforming matrix, so that the amount of data transmitted by the first network device to the second network device can be reduced. For example, the first information can indicate the at least one codebook by using a codebook index, i.e., the first information can include an index of the at least one codebook, and the data amount of the index of the at least one codebook is much less than the data amount of the entire beamforming matrix.

[0222] In addition, when the number of radio frequency channels is less than the number of antenna elements, the first network device can obtain an analog domain codebook by projecting a second beamforming matrix or a first channel matrix onto an analog domain codebook set, and instruct the second network device to use the analog domain codebook as a second-stage matrix and perform secondary beamforming for downlink transmission based on the second-stage matrix, thereby achieving a more accurate beam direction.

[0223] In addition, the first network device may determine a second beamforming matrix based on one or more of an SRS beamforming matrix, a PMI beamforming matrix, a DMRS beamforming matrix, and a static beamforming matrix, and generate the first information based on the second beamforming matrix. Alternatively, the first network device may determine a first channel matrix based on a plurality of channel matrices among a channel matrix obtained based on an SRS measurement channel, a channel matrix obtained based on a CSI-RS measurement channel, and a channel matrix obtained based on a DMRS measurement channel, and generate the first information based on the first channel matrix. Correspondingly, the performance of the first beamforming matrix determined by the second network device based on the first information is better, so that the downlink transmission performance can be improved.

[0224] Please refer to the description of FIG. 2 above. If the first network device is a control device, the first network device can further transmit the first information or the information indicating at least one codebook and the weighting factor matrix corresponding to the at least one codebook to the third network device after generating the first information. The third network device is a radio frequency device or a control device, and the third network device and the second network device belong to different cells. If the third network device is a control device, the third network device can further transmit the first information or the information indicating at least one codebook and the weighting factor matrix corresponding to the at least one codebook to a radio frequency device connected to the third network device. Furthermore, the third network device or the radio frequency device connected to the third network device can determine a third beamforming matrix based on the at least one codebook and the weighting factor matrix corresponding to the at least one codebook or based on the first beamforming matrix. Therefore, when a third network device or a radio frequency device connected to the third network device performs beamforming on a downlink transmission signal using a third beamforming matrix, interference to users served by the second network device can be avoided as much as possible, or interference caused by users served by the second network device to users served by the third network device or a radio frequency device connected to the third network device can be avoided as much as possible.

[0225] When the first network device is a radio frequency device and the second network device is a control device, the second network device can transmit the first information or the information indicating the at least one codebook and the weighting factor matrix corresponding to the at least one codebook to the fourth network device after receiving the first information from the first network device. The fourth network device is a radio frequency device or a control device. When the fourth network device is a control device, the fourth network device can further transmit the first information or the information indicating the at least one codebook and the weighting factor matrix corresponding to the at least one codebook to a radio frequency device connected to the fourth network device. Furthermore, the fourth network device or the radio frequency device connected to the fourth network device can determine a fourth beamforming matrix based on the at least one codebook and the weighting factor matrix corresponding to the at least one codebook or based on the first beamforming matrix. Therefore, when the fourth network device or a radio frequency device connected to the fourth network device performs beamforming on a downlink transmission signal using the fourth beamforming matrix, interference to users served by the first network device can be avoided as much as possible, or interference caused by users served by the first network device to users served by the fourth network device or a radio frequency device connected to the fourth network device can be avoided as much as possible.

[0226] As shown in (a) of Figure 4, after BBL1 (a functional module included in a first network device) sends first information to BBH (a functional module included in a second network device), BBH can send the first information to BBL2 (a functional module included in a fourth network device). BBL2 can receive the first information and determine a first beamforming matrix based on the first information.

[0227] As shown in (b) of FIG. 4, after BBL1 (functional module included in the first network device) sends the first information to BBH1 (functional module included in the second network device), BBH1 can send the first information to BBH2 (functional module included in the fourth network device). BBH2 receives the first information and then sends the first information to BBL2. After receiving the first information, BBL2 can determine a first beamforming matrix based on the first information. Optionally, in the process of BBH1 sending the first information to BBH2, specifically, BBH1 may send the first information to BBH2 using DU1 including BBH1. For example, DU1 may directly send the first information to BBH2, or DU1 sends the first information to CU1 connected to DU1, and then CU1 sends the first information to BBH2. Optionally, in the process of BBH1 transmitting the first information to BBH2, BBH1 may specifically transmit the first information to CU1, and then CU1 transmits the first information to BBH2. Optionally, in the process of BBH1 / CU1 / DU1 transmitting the first information to BBH2, BBH1 / CU1 / DU1 may specifically transmit the first information directly to BBH2, or BBH1 / CU1 / DU1 may transmit the first information to DU2 including BBH2, or BBH1 / CU1 / DU1 may transmit the first information to CU2, and then CU2 transmits the first information to DU2 / BBH2.

[0228] As described above, when the first beamforming matrix is ​​determined based on the first information, specifically, at least one codebook is determined based on at least one codebook set and the first information, and then the first beamforming matrix is ​​determined based on at least one codebook and the weighting coefficient matrix of the at least one codebook. Therefore, when the third network device and the first network device belong to different operators, the operators to which the third network device and the first network device belong can agree in advance on at least one codebook set so that the third network device or the radio frequency device connected to the third network device can determine the first beamforming matrix based on the first information. For example, the operators to which the third network device and the first network device belong can agree in advance that the spatial domain codebook set is a DFT matrix. As another example, the operators to which the third network device and the first network device belong can agree in advance that the spatial domain codebook set is an oversampling DFT matrix. It will be understood that, when the third network device and the operator to which the first network device belongs have pre-agreed on at least one codebook set, the first network device determines the first information based on the at least one pre-agreed codebook set. Correspondingly, the third network device or a radio frequency device connected to the third network device determines the first beamforming matrix based on the at least one pre-agreed codebook set.

[0229] The manner in which each operator agrees on at least one codebook set in advance is not limited to this embodiment of the present application. For example, if at least one codebook set is specified in a protocol, each operator can agree on at least one codebook set by agreeing on the protocol to be used in advance. As another example, each operator can also agree on at least one codebook set in advance through a subscription.

[0230] Similarly, if the fourth network device and the first network device belong to different operators, the operators to which the fourth network device and the first network device belong may pre-agree on at least one codebook set.

[0231] Above, the method provided in the embodiment of the present application is described in detail with reference to Fig. 3. Hereinafter, the device provided in the embodiment of the present application is described in detail with reference to Fig. 5 to Fig. 7. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for the contents that are not described in detail, please refer to the above-mentioned method embodiment. For the sake of brevity, the details will not be described again here.

[0232] 5 is a schematic block diagram of an apparatus 1000 according to an embodiment of the present application. As shown in this figure, the apparatus 1000 may include a transceiver unit 1010 and a processing unit 1020.

[0233] In one possible design, the apparatus 1000 may be a first network device in the aforementioned method embodiment, or may be a chip configured to perform the functions of the first network device in the aforementioned method embodiment.

[0234] It should be understood that the apparatus 1000 may correspond to the first network device in the method 300 according to the embodiment of the present application, and the apparatus 1000 may include units configured to execute the method performed by the first network device in the method 300 of Fig. 2. In addition, the units in the apparatus 1000 and other operations and / or functions described above are separately used to implement the corresponding procedures of the method 300 of Fig. 3. It should be understood that the specific processes in which the units execute the corresponding steps described above are described in detail in the embodiment of the method described above. For the sake of brevity, the details will not be described again here.

[0235] For example, the processing unit 1020 included in the device 1000 may correspond to the generating module shown in Fig. 2(a). Optionally, the processing unit 1020 may further correspond to the calculation module and the quantization module shown in Fig. 2(a). Alternatively, the processing unit 1020 included in the device 1000 may correspond to the generating module shown in Fig. 2(b). Optionally, the processing unit 1020 may further correspond to the calculation module, the quantization module, the reconstruction module, and the beamforming module shown in Fig. 2(b).

[0236] In another possible design, the apparatus 1000 may be a second network device in the aforementioned method embodiment, or may be a chip configured to perform the functions of the second network device in the aforementioned method embodiment.

[0237] It should be understood that the apparatus 1000 may correspond to the second network device in the method 300 according to the embodiment of the present application, and the apparatus 1000 may include units configured to execute the method performed by the second network device in the method 300 of Fig. 3. In addition, the units in the apparatus 1000 and other operations and / or functions described above are separately used to implement the corresponding procedures of the method 300 of Fig. 3. It should be understood that the specific processes in which the units execute the corresponding steps described above are described in detail in the embodiment of the method described above. For the sake of brevity, the details will not be described again here.

[0238] For example, the processing unit 1020 included in the apparatus 1000 may correspond to the reconstruction module and the beamforming module shown in FIG. 2(a).

[0239] It should be further understood that the transceiver unit 1010 in the apparatus 1000 may correspond to the transceiver 2020 in the apparatus 2000 shown in FIG. 6, and the processing unit 1020 in the apparatus 1000 may correspond to the processor 2010 in the apparatus 2000 shown in FIG. 6.

[0240] It should be further understood that if the device 1000 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, a microprocessor, or an integrated circuit integrated on a chip.

[0241] The transceiver unit 1010 is configured to perform signal reception and transmission operations of the apparatus 1000 , and the processing unit 1020 is configured to perform signal processing operations of the apparatus 1000 .

[0242] Optionally, the apparatus 1000 further includes a storage unit 1030 configured to store instructions.

[0243] FIG. 6 is a schematic block diagram of an apparatus 2000 according to an embodiment of the present application. As shown in FIG. 6, the apparatus 2000 includes at least one processor 2010. The processor 2010 is coupled to a memory and configured to execute instructions stored in the memory to perform the method described in FIG. 3. Optionally, the apparatus 2000 further includes a transceiver 2020. The processor 2010 is coupled to the memory and configured to execute instructions stored in the memory to control the transceiver 2020 to transmit and / or receive a signal. For example, the processor 2010 can control the transceiver 2020 to transmit and / or receive a first information. Optionally, the apparatus 2000 further includes a memory 2030 configured to store instructions.

[0244] It should be understood that the processor 2010 and the memory 2030 may be integrated into one processing unit. The processor 2010 is configured to execute program codes stored in the memory 2030 to perform the functions described above. In a specific implementation, the memory 2030 may be integrated into the processor 2010 or may be separate from the processor 2010.

[0245] It should be further understood that the transceiver 2020 may include a receiver (or referred to as a receiver) and a transmitter (or referred to as a transmitter). The transceiver 2020 may further include an antenna. There may be one or more antennas. Alternatively, the transceiver 2020 may be a communication interface or interface circuit.

[0246] When the device 2000 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, a microprocessor, or an integrated circuit integrated on the chip.

[0247] 7 is a schematic diagram of a chip system according to an embodiment of the present application. The chip system here may be a system including a circuit. The chip system 3000 shown in FIG. 7 includes a logic circuit 3010 and an input / output interface 3020. The logic circuit is coupled to the input interface and configured to transmit data (e.g., first information) using the input / output interface to perform the method described in FIG. 3.

[0248] An embodiment of the present application further provides a processing device including a processor and an interface. The processor may be configured to perform the method of the aforementioned method embodiments.

[0249] It should be understood that the processing device may be a chip, for example, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a micro controller unit (MCU), a programmable logic device (PLD), or another integrated chip.

[0250] In the course of implementation, the steps of the aforementioned method may be completed by using hardware integrated logic circuits in a processor or by using instructions in the form of software. The steps of the method disclosed with reference to the embodiments of the present application may be directly executed by a hardware processor, or may be executed using a combination of hardware and software modules in a processor. The software modules may be disposed in a mature storage medium in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, an electrically erasable programmable memory, or a register. The storage medium is disposed in the memory, and the processor reads the information in the memory and completes the steps of the aforementioned method in cooperation with the hardware in the processor. In order to avoid repetition, details will not be described here.

[0251] It should be noted that the processor in the embodiments of the present application may be an integrated circuit chip and has signal processing capabilities. In the course of implementation, the steps of the above-mentioned method embodiments may be completed by using hardware integrated logic circuits in the processor or by using instructions in the form of software. The processor may be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or another programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. The processor can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor, or the processor may be any conventional processor, etc.

[0252] It is understood that the memory in this embodiment of the present application may be volatile or non-volatile memory, or may include volatile and non-volatile memory. The non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory may be random access memory (RAM) and is used as an external cache.

[0253] According to the method provided in the embodiment of the present application, the present application further provides a computer program product, which includes computer program code, which, when executed on a computer, enables the computer to perform the method of the embodiment shown in FIG.

[0254] According to the method provided in the embodiment of the present application, the present application further provides a computer-readable medium, which stores a program code, which, when executed on a computer, enables the computer to perform the method of the embodiment shown in FIG.

[0255] According to the method provided in the embodiment of the present application, the present application further provides a system, which includes the above-mentioned first network device and a second network device.

[0256] All or part of the above-mentioned embodiments may be implemented by using software, hardware, firmware, or any combination thereof. When software is used for implementation, the embodiments may 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 instructions are loaded into a computer and executed, all or part of the procedures or functions according to the embodiments of the present application are generated. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. The computer-readable storage medium may be any available medium accessible by a computer, or may be a data storage device that integrates one or more available media, such as a server or a data center. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk drive, or a magnetic tape), an optical medium (e.g., a digital video disc (DVD)), a semiconductor medium (e.g., a solid state disc (SSD)), etc.

[0257] In some embodiments provided in the present application, it should be understood that the disclosed system, device, and method may be implemented in other ways. For example, the above-mentioned device embodiment is only an example. For example, the division of units is only a logical division of functions, and there may be other division ways in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not implemented. In addition, the shown or discussed mutual couplings or direct couplings or communication connections may be implemented using some interfaces. Indirect couplings or communication connections between devices or units may be implemented in electrical, mechanical, or other forms.

[0258] The above description is merely a specific implementation of the present application, and is not intended to limit the scope of protection of the present application. Any modifications or replacements that are easily conceived by those skilled in the art within the technical scope disclosed in this application shall fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the scope of protection of the claims. [Explanation of symbols]

[0259] 1000 devices 1010 Transceiver unit 1020 Processing Unit 1030 Storage Unit 2000 equipment 2010 Processors 2020 Transceiver 2030 Memory 3000 Chip System 3010 Logic Circuit 3020 Input / Output Interface

Claims

1. generating, by a first network device, first information, the first information indicating at least one codebook and a weighting factor matrix corresponding to the at least one codebook, the at least one codebook and the weighting factors corresponding to the at least one codebook being used to determine a first beamforming matrix; transmitting, by the first network device, the first information to a second network device; A transmission method including:

2. The method of claim 1 , wherein the first information indicates a column vector or a row vector included in the at least one codebook.

3. The method of claim 1 or 2, wherein the at least one codebook comprises a first codebook.

4. The method of claim 1 or 2, wherein the at least one codebook includes a first codebook and a second codebook.

5. 4. The method of claim 1, wherein the first beamforming matrix includes a first stage matrix and a second stage matrix, the at least one codebook includes the first codebook and a third codebook, the weighting coefficient matrix corresponding to the at least one codebook corresponds to the first codebook, the first codebook and the weighting coefficient matrix are used to determine the first stage matrix, and the third codebook is used to determine the second stage matrix.

6. 3. The method of claim 1, wherein the first beamforming matrix includes a first stage matrix and a second stage matrix, the at least one codebook includes a first codebook, a second codebook, and a third codebook, the weighting coefficient matrix corresponding to the at least one codebook corresponds to the first codebook and the second codebook, the first codebook, the second codebook, and the weighting coefficient matrix are used to determine the first stage matrix, and the third codebook is used to determine the second stage matrix.

7. The method comprises:

7. The method of claim 1, further comprising: determining, by the first network device, the at least one codebook and the weighting factor matrix corresponding to the at least one codebook based on a second beamforming matrix and at least one codebook set, wherein the second beamforming matrix is ​​determined based on one or more of a beamforming matrix determined based on a sounding reference signal (SRS) measurement channel, a beamforming matrix determined based on a channel state information and reference signal (CSI-RS) measurement channel, a beamforming matrix determined based on a demodulation reference signal (DMRS) measurement channel, and a static beamforming matrix.

8. The step of determining, by the first network device, the at least one codebook and the weighting coefficient matrix corresponding to the at least one codebook based on a second beamforming matrix and at least one codebook set, further comprises:

8. The method of claim 7, comprising: projecting, by the first network device, the second beamforming matrix onto the at least one codebook set to obtain the at least one codebook and the weighting factor matrix corresponding to the at least one codebook that maximizes channel capacity and / or maximizes channel throughput.

9. The method comprises:

7. The method of claim 1, further comprising: determining, by the first network device, the at least one codebook and the weighting factor matrix corresponding to the at least one codebook based on a first channel matrix and at least one codebook set, wherein the first channel matrix is ​​determined based on one or more of a channel matrix determined based on an SRS measurement channel, a channel matrix determined based on a CSI-RS measurement channel, and a channel matrix determined based on a DMRS measurement channel.

10. The step of determining, by the first network device, the at least one codebook and the weighting coefficient matrix corresponding to the at least one codebook based on a first channel matrix and at least one codebook set, includes:

10. The method of claim 9, comprising: projecting, by the first network device, the first channel matrix onto the at least one codebook set to obtain the at least one codebook and the weighting factor matrix corresponding to the at least one codebook that maximizes channel capacity and / or maximizes channel throughput.

11. 11. The method of claim 7, wherein the at least one codebook set includes at least one of a first codebook set, a second codebook set, and a third codebook set.

12. 12. The method of claim 3, wherein the first codebook, the second codebook, or the third codebook is one of the following codebooks: a spatial domain codebook, a frequency domain codebook, or an analog domain codebook.

13. 13. The method of claim 1, wherein the first network device is a control device and the second network device is a radio frequency device, or the first network device is a radio frequency device and the second network device is a control device.

14. the first network device is a control device and the second network device is a radio frequency device, the method comprising:

13. The method of claim 1, further comprising: transmitting, by the first network device, information indicating the at least one codebook and the weighting factor matrix corresponding to the at least one codebook to a third network device, wherein the third network device and the second network device belong to different cells.

15. The first network device is a radio frequency device and the second network device is a control device, the method comprising:

13. The method of claim 1, further comprising: performing, by the first network device, beamforming on a signal using a first beamforming matrix.

16. receiving, by a second network device, first information from the first network device, the first information indicating at least one codebook and a weighting factor matrix corresponding to the at least one codebook, the at least one codebook and the weighting factor matrix corresponding to the at least one codebook being used to determine a first beamforming matrix; determining, by the second network device, the at least one codebook and the weighting factor matrix corresponding to the at least one codebook based on the first information; A transmission method including:

17. The method of claim 16 , wherein the first information indicates a column vector or a row vector included in the at least one codebook.

18. 18. The method of claim 16 or 17, wherein the at least one codebook comprises a first codebook.

19. 18. The method of claim 16 or 17, wherein the at least one codebook includes a first codebook and a second codebook.

20. 19. The method of claim 16, wherein the first beamforming matrix includes a first stage matrix and a second stage matrix, the at least one codebook includes the first codebook and a third codebook, the weighting coefficient matrix corresponding to the at least one codebook corresponds to the first codebook, the first codebook and the weighting coefficient matrix are used to determine the first stage matrix, and the third codebook is used to determine the second stage matrix.

21. 19. The method of claim 16, wherein the first beamforming matrix includes a first stage matrix and a second stage matrix, the at least one codebook includes the first codebook, a second codebook, and a third codebook, the weighting coefficient matrix corresponding to the at least one codebook corresponds to the first codebook and the second codebook, the first codebook, the second codebook, and the weighting coefficient matrix are used to determine the first stage matrix, and the third codebook is used to determine the second stage matrix.

22. 22. The method of claim 18, wherein the first codebook, the second codebook, or the third codebook is one of the following codebooks: a spatial domain codebook, a frequency domain codebook, or an analog domain codebook.

23. 23. The method of claim 16, wherein the first network device is a control device and the second network device is a radio frequency device, or the first network device is a radio frequency device and the second network device is a control device.

24. The first network device is a radio frequency device and the second network device is a control device, the method comprising:

24. The method of claim 16, further comprising: transmitting, by the second network device, information indicating the at least one codebook and the weighting factor matrix corresponding to the at least one codebook to a fourth network device, wherein the fourth network device and the first network device belong to different cells.

25. the first network device is a control device and the second network device is a radio frequency device, the method comprising: determining, by the second network device, the first beamforming matrix based on the first information; performing, by the second network device, beamforming on a signal using the first beamforming matrix; 24. The method of any one of claims 16 to 23, further comprising:

26. 26. A communications device comprising at least one processor, the at least one processor being coupled to a memory and configured to read and execute instructions in the memory to implement a method according to any one of claims 1 to 25.

27. 27. The communication device of claim 26, further comprising the memory.

28. A communication device comprising a unit configured to carry out a method according to any one of claims 1 to 25.

29. A computer program product comprising instructions, which when executed on a computer, enables the computer to carry out the method according to any one of claims 1 to 25.

30. 26. A computer readable storage medium, the computer readable storage medium storing a computer program which, when executed, performs the method of any one of claims 1 to 25.

31. A system comprising a first network device and a second network device, the first network device configured to perform the method of any one of claims 1 to 15, and the second network device configured to perform the method of any one of claims 16 to 25.

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