WO2022021443A1 - 一种预编码方法及装置 - Google Patents

一种预编码方法及装置 Download PDF

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Publication number
WO2022021443A1
WO2022021443A1 PCT/CN2020/106448 CN2020106448W WO2022021443A1 WO 2022021443 A1 WO2022021443 A1 WO 2022021443A1 CN 2020106448 W CN2020106448 W CN 2020106448W WO 2022021443 A1 WO2022021443 A1 WO 2022021443A1
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Prior art keywords
matrix
precoding
precoding matrices
network device
reference signal
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PCT/CN2020/106448
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English (en)
French (fr)
Inventor
张霄宇
徐明涛
胥恒
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华为技术有限公司
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Priority to CN202080098247.5A priority Critical patent/CN115244864A/zh
Priority to PCT/CN2020/106448 priority patent/WO2022021443A1/zh
Publication of WO2022021443A1 publication Critical patent/WO2022021443A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present application relates to the field of communication technologies, and in particular, to a precoding method and apparatus.
  • the Large-scale antenna arrays (tens or even hundreds of antennas) are arranged on the side to serve multiple users in the coverage area at the same time.
  • Massive multiple input multiple output (massive multiple input multiple output, massive MIMO) technology can significantly improve the system performance.
  • Spectral efficiency and energy efficiency For example, when a massive MIMO system performs downlink transmission, the base station (BS) usually performs beamforming (also called precoding).
  • the weighting coefficients of can be called the weight matrix.
  • the amplitude and phase of the transmitting units on each antenna can be adjusted through the weight matrix, so that the signal is sent in a fixed direction.
  • precoding includes a codebook-based transmission mode and a non-codebook-based transmission mode, where the codebook-based transmission mode can be applied to frequency division duplex (Frequency division duplex, FDD) and (Time division duplex, TDD) systems, while non-codebook based transmission modes are commonly used in TDD systems.
  • FDD Frequency division duplex
  • TDD Time division duplex
  • the terminal selects an appropriate codebook from a predefined codebook set according to the channel state, and indicates the index of the selected codebook to the base station through the control channel.
  • the base station selects an appropriate precoding matrix through the index of the codebook indicated by the terminal, uses this as a reference to reconstruct the downlink channel, and determines the weight matrix used for beamforming.
  • the 3rd Generation Partnership Project (3GPP) protocol stipulates that only a finite number of discrete precoding matrices in the codebook can be used to quantize infinite Therefore, when the base station performs channel reconstruction and beamforming according to the codebook index fed back by the user, the resulting quantization error will cause the beam direction determined by the precoding matrix to deviate from the actual channel beam direction, so that User transfer rates are significantly reduced.
  • the present application provides a precoding method and apparatus for improving the beamforming accuracy of network equipment.
  • the present application provides a precoding method, including: a network device sending N-1 reference signals to a terminal device; the network device receiving N-1 reference signals corresponding to the N-1 reference signals from the terminal device Indication information of 1 precoding matrix; the network device sends the Nth reference signal to the terminal device, and the Nth reference signal is obtained by weighting with a weighting matrix, and the weighting matrix is the same as the N-1 reference signal.
  • At least one precoding matrix of the number of precoding matrices is orthogonal; the network device receives the indication information of the Nth precoding matrix corresponding to the Nth reference signal from the terminal device; the network device according to the Nth precoding matrix
  • the coding matrix determines a reconstruction matrix, and the N precoding matrices include the N-1 precoding matrices and the Nth precoding matrix; the network device sends a downlink signal according to the reconstruction matrix; the N-1 is a positive integer.
  • N-1 can be replaced by M
  • N can be replaced by M+1
  • M is a positive integer.
  • the network device generates a weighting matrix for the next transmission according to the precoding matrix fed back by the terminal device, for example, the weighting matrix used for the Nth reference signal and at least one precoding matrix of the N-1 precoding matrices fed back by the terminal device Orthogonal, so that the Nth precoding matrix fed back by the terminal device is orthogonal to at least one precoding matrix of the N-1 precoding matrices fed back before, which reduces redundant information in the precoding matrix and provides better feedback Therefore, the network device can generate a reconstruction matrix according to the N precoding matrices, which effectively improves the accuracy of the reconstruction matrix in describing the channel characteristics and improves the accuracy of beamforming.
  • the weighting matrix F N satisfies:
  • V c (N-1) represents the first matrix formed by the N-1 precoding matrices; represents the conjugate transpose matrix of the first matrix.
  • the weighting matrix adopted by the Nth reference signal is orthogonal to the N-1 precoding matrices fed back by the terminal device, so that the N precoding matrices fed back by the terminal device have no redundant information, and it is possible to Through the limited number of feedbacks, the eigenvectors in the rank required for the reconstruction of the channel are realized, which effectively improves the accuracy of the channel characteristics described by the reconstruction matrix, improves the accuracy of beamforming, and effectively reduces the overhead of the feedback precoding matrix. And the network equipment calculates the amount of calculation of the reconstruction matrix.
  • the first matrix satisfies:
  • V c (N-1) [V 1 ,V 2 ,...V N-1 ]
  • V k represents the kth precoding matrix in the N ⁇ 1 precoding matrices; the k ⁇ [1,N ⁇ 1]; the k is a positive integer.
  • the first matrix is generated by combining N-1 precoding matrices, the complexity of determining the first matrix is low, and the calculation amount of the network device for determining the weighting matrix is reduced.
  • the number of layers of the i-th pre-coding matrix in the N pre-coding matrices is v i ; the i -th pre-coding matrix corresponds to the vi eigenvectors in the reconstruction matrix ; the i ⁇ [1,N]; the i is a positive integer; the v i is a positive integer.
  • the feedback precoding matrix can correspond to the eigenvectors of the corresponding number of layers, without the need for the terminal equipment to repeatedly feedback to improve beamforming efficiency.
  • the network device determines the reconstruction matrix according to the weighted N precoding matrices.
  • the rank of the precoding matrix and the rank of the reconstruction matrix can be the same, the reconstruction matrix can be determined according to the weighted N precoding matrices, the channel characteristics in the N precoding matrices can be effectively used, and the rank of the reconstruction matrix can be improved. precision.
  • the reconstruction matrix is determined according to the first covariance matrix Z1; the first covariance matrix Z1 satisfies:
  • 0 ⁇ i ⁇ 1, and ⁇ i represents the weight coefficient corresponding to the i-th precoding matrix in the N precoding matrices in the first covariance matrix;
  • the V i represents the ith precoding matrix in the N precoding matrices;
  • the Re represents the conjugate transpose matrix of the ith precoding matrix in the N precoding matrices;
  • the i ⁇ [1,N]; the i is a positive integer.
  • the first covariance matrix is determined according to the N precoding matrices, so that the first covariance matrix is weighted and normalized, thereby effectively utilizing the channel features in the N precoding matrices and improving the accuracy of the reconstruction matrix .
  • the network device determines the reconstruction matrix according to a second matrix composed of N precoding matrices; the second matrix satisfies:
  • V c [V 1 ,V 2 ,...V N ]
  • V i represents the ith precoding matrix in the N precoding matrices; the i ⁇ [1,N]; the i is a positive integer.
  • the rank of the N precoding matrices can be different from the rank of the reconstruction matrix, and the number of layers of the different precoding matrices and the number of eigenvectors required for the reconstruction matrix can be used to determine the number of eigenvectors to be fed back by the terminal device.
  • the times of the precoding matrix and the rank of the reconstruction matrix are not limited to the rank of the feedback precoding matrix, which can improve the adaptability of the reconstruction matrix.
  • the number of layers of the ith precoding matrix in the N precoding matrices is 1; the network device receives the channel quality corresponding to the ith reference signal from the terminal device Information (channel quality information, CQI) value; the i ⁇ [1,N]; the i is a positive integer.
  • CQI channel quality information
  • the precoding matrix fed back by the terminal device may correspond to an eigenvector in one reconstruction matrix, so that, according to the feedback CQI value, as the eigenvalue of the eigenvector,
  • the characteristics of the channel are further provided, which is beneficial for the network device to obtain a more accurate reconstruction matrix and improve the accuracy of beamforming.
  • the reconstruction matrix is determined according to the second covariance matrix Z2; the second covariance matrix Z2 satisfies:
  • C i represents the CQI value corresponding to the ith reference signal
  • V i represents the ith precoding matrix in the N precoding matrices
  • the Re represents the conjugate transpose matrix of the ith precoding matrix in the N precoding matrices
  • the i ⁇ [1,N]; the i is a positive integer.
  • the precoding matrix fed back by the terminal device can correspond to an eigenvector in one reconstruction matrix. Therefore, according to the feedback CQI value, as the eigenvalue of the eigenvector, as the weight in the weighted precoding matrix, there are It is beneficial for network equipment to obtain a more accurate reconstruction matrix and improve the accuracy of beamforming.
  • the present application provides a communication device, for example, the communication device is a network device as before.
  • the communication device is configured to perform the method in the above-mentioned first aspect or any possible implementation manner.
  • the communication apparatus may include modules for performing the method in the first aspect or any possible implementation manner, for example, including a processing module and a transceiver module.
  • the transceiver module may include a sending module and a receiving module, and the sending module and the receiving module may be different functional modules, or may be the same functional module, but can implement different functions.
  • the communication device is a communication device, or a chip or other components provided in the communication device.
  • the communication device is a network device.
  • the transceiver module can also be implemented by a transceiver, and the processing module can also be implemented by a processor.
  • the sending module may be implemented by a transmitter
  • the receiving module may be implemented by a receiver
  • the transmitter and the receiver may be different functional modules, or may be the same functional module but capable of implementing different functions.
  • the communication device is a communication device
  • the transceiver is implemented by, for example, an antenna, a feeder, a codec and the like in the communication device.
  • the transceiver (or the transmitter and the receiver) is, for example, a communication interface in the chip, and the communication interface is connected with the radio frequency transceiver component in the communication device to transmit radio frequency
  • the transceiver component realizes the sending and receiving of information.
  • a communication apparatus is provided, and the communication apparatus is, for example, the above-mentioned network equipment.
  • the communication device includes a processor and a communication interface that can be used to communicate with other devices or devices.
  • the communication device may further include a memory for storing computer instructions.
  • the processor and the memory are coupled to each other for implementing the method described in the first aspect or various possible implementation manners.
  • the communication device may not include the memory, and the memory may be located outside the communication device.
  • the processor, the memory and the communication interface are coupled to each other, and are used for implementing the method described in the first aspect or various possible implementation manners.
  • the communication apparatus is caused to perform the method in the above-mentioned first aspect or any one of the possible implementation manners.
  • the communication device is a communication device, or a chip or other components provided in the communication device.
  • the communication device is a network device.
  • the communication interface is realized by, for example, a transceiver (or a transmitter and a receiver) in the communication device, for example, the transceiver is realized by an antenna, a feeder and a codec in the communication device.
  • the communication interface is, for example, an input/output interface of the chip, such as input/output pins, etc.
  • the transceiver component realizes the sending and receiving of information.
  • a chip in a fourth aspect, includes at least one processor and a transceiver, the transceiver and the at least one processor are interconnected through a line, and the processor executes the above-mentioned first step by running an instruction.
  • a fifth aspect provides a computer-readable storage medium, where the computer-readable storage medium is used to store a computer program, and when the computer program runs on a computer, the computer is made to execute the above-mentioned first aspect or any one of the possible implementations. method.
  • a sixth aspect provides a computer program product comprising instructions, the computer program product is used to store a computer program, and when the computer program is run on a computer, the computer executes the method in any possible implementation manner of the first aspect above .
  • FIG. 1a is a schematic diagram of a scenario applicable to an embodiment of the present application.
  • FIG. 1b is a schematic diagram of a scenario applicable to an embodiment of the present application.
  • FIG. 2 is a schematic flowchart of a precoding method provided by an embodiment of the present application.
  • FIG. 3 is a schematic flowchart of a precoding method provided by an embodiment of the present application.
  • FIG. 4 is a schematic flowchart of a precoding method provided by an embodiment of the present application.
  • FIG. 5 is a schematic flowchart of a precoding method provided by an embodiment of the present application.
  • FIG. 6 is a schematic structural diagram of a communication device according to an embodiment of the present application.
  • FIG. 7 is a schematic structural diagram of a communication apparatus according to an embodiment of the present application.
  • the precoding method provided by this application can be applied to various communication systems.
  • the communication system provided by this application may be a long term evolution (LTE) system supporting 4G access technology, a new wireless (LTE) system supporting 5G access technology.
  • new radio, NR new radio
  • 3GPP 3rd generation partnership project
  • WiFi wireless-fidelity
  • WiMAX worldwide interoperability for microwave access
  • WiMAX multiple radio access technology
  • RAT Radio Access Technology
  • it can be an internet of things (IoT) system, a narrow band internet of things (NB-IoT) system, a long term evolution (LTE) system, or a fifth generation (5G) system.
  • IoT internet of things
  • NB-IoT narrow band internet of things
  • LTE long term evolution
  • 5G fifth generation
  • communication system it can also be a hybrid architecture of LTE and 5G, it can also be an NR system, and a new communication system that will appear in future communication development.
  • This application is applicable to a 5G NR Frequency Division Duplexing (FDD) MIMO system and a 5G NR Time Division Duplexing (TDD) MIMO system.
  • FDD Frequency Division Duplexing
  • TDD Time Division Duplexing
  • Terminal devices including devices that provide voice and/or data connectivity to users, for example, may include handheld devices with wireless connectivity, or processing devices connected to wireless modems.
  • the terminal equipment may communicate with the core network via a radio access network (RAN), and exchange voice and/or data with the RAN.
  • RAN radio access network
  • the terminal in this application is a device with wireless transceiver function, which can be deployed on land, including indoor or outdoor, handheld, wearable or vehicle-mounted; it can also be deployed on water (such as ships, etc.); it can also be deployed in the air (such as unmanned aircraft, planes, balloons and satellites, etc.).
  • the terminal can be a mobile phone (mobile phone), a tablet computer (Pad), a computer with a wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, an industrial control (industrial control) wireless terminals in self-driving, wireless terminals in remote medical, wireless terminals in smart grid, wireless terminals in transportation safety, Wireless terminals in smart cities, wireless terminals in smart homes, and so on.
  • the embodiments of the present application do not limit application scenarios.
  • a terminal may also sometimes be referred to as terminal equipment, user equipment (UE), access terminal equipment, station, UE unit, UE station, mobile station, mobile station, remote station, remote terminal equipment, mobile equipment, UE terminal equipment , terminal device, wireless communication device, UE proxy or UE device, or some other suitable term. Terminals can also be stationary or mobile.
  • the terminal equipment may include a vehicle, a vehicle module, a user equipment (UE), a wireless terminal equipment, a mobile terminal equipment, a subscriber unit, a subscriber station, a mobile station (mobile station), mobile station (mobile), remote station (remote station), access point (AP), remote terminal equipment (remote terminal), access terminal equipment (access terminal), user terminal equipment (user terminal), user agent, or user device, etc.
  • it may include mobile phones (or “cellular” phones), computers with mobile terminal equipment, portable, pocket-sized, hand-held, computer-built or vehicle-mounted mobile devices, smart wearable devices, and the like.
  • PCS personal communication service
  • SIP session initiation protocol
  • WLL wireless local loop
  • PDA personal digital assistant
  • constrained devices such as devices with lower power consumption, or devices with limited storage capacity, or devices with limited computing power, etc.
  • information sensing devices such as barcodes, radio frequency identification (RFID), sensors, global positioning system (GPS), and laser scanners.
  • the terminal device may also be a wearable device.
  • Wearable devices can also be called wearable smart devices, which are the general term for the intelligent design of daily wear and the development of wearable devices using wearable technology, such as glasses, gloves, watches, clothing and shoes.
  • a wearable device is a portable device that is worn directly on the body or integrated into the user's clothing or accessories. Wearable device is not only a hardware device, but also realizes powerful functions through software support, data interaction, and cloud interaction.
  • wearable smart devices include full-featured, large-scale, complete or partial functions without relying on smart phones, such as smart watches or smart glasses, and only focus on a certain type of application function, which needs to cooperate with other devices such as smart phones.
  • Use such as all kinds of smart bracelets, smart helmets, smart jewelry, etc. for physical sign monitoring.
  • the terminal device in this embodiment of the present application may also be an on-board module, on-board module, on-board component, on-board chip or on-board unit built into the vehicle as one or more components or units.
  • a group, an on-board component, an on-board chip, or an on-board unit may implement the methods of the embodiments of the present application.
  • the network device is a device with a wireless transceiver function or a chip that can be installed in the device, and the device includes but is not limited to: an evolved Node B (evolved Node B, eNB), a radio network controller (radio network controller, RNC), node B (Node B, NB), base station controller (BSC), base transceiver station (base transceiver station, BTS), home base station (for example, home evolved NodeB, or home Node B, HNB), baseband unit ( baseband unit, BBU), access point (AP), wireless relay node, wireless backhaul node, transmission point (transmission and reception point, TRP or transmission point) in wireless fidelity (wireless fidelity, WIFI) systems , TP), etc., can also be 5G, such as, NR, gNB in the system, or, transmission point (TRP or TP), one or a group (including multiple antenna panels) antenna panels of the base station in the 5G system, or , and may also be a
  • a gNB may include a centralized unit (CU) and a DU.
  • the gNB may also include a radio unit (RU).
  • CU implements some functions of gNB
  • DU implements some functions of gNB, for example, CU implements radio resource control (radio resource control, RRC), packet data convergence protocol (packet data convergence protocol, PDCP) layer functions
  • DU implements wireless chain
  • the functions of the road control radio link control, RLC
  • media access control media access control, MAC
  • physical (physical, PHY) layers The functions of the road control (radio link control, RLC), media access control (media access control, MAC) and physical (physical, PHY) layers.
  • the network device may be a CU node, or a DU node, or a device including a CU node and a DU node.
  • the CU may be divided into network equipment in the access network RAN, and the CU may also be divided into network equipment in the core network CN, which is not limited herein.
  • a beam is a communication resource.
  • the beams can be wide beams, or narrow beams, or other types of beams. Different beams can be considered as different resources (the resources can be spatial domain resources).
  • the beam-forming technology may be beamforming technology or other technical means.
  • the beamforming technology may specifically be a digital beamforming technology, an analog beamforming technology, and a hybrid digital/analog beamforming technology.
  • the same information or different information can be sent through different beams.
  • multiple beams with the same or similar communication characteristics may be regarded as one beam.
  • a beam can be sent through one or more antenna ports, and the beam is used to transmit data channels, control channels, and sounding signals, etc., for example, the distribution of signal strength that can be formed in different directions in space after the signal is transmitted through the beam. It can be understood that one or more antenna ports forming a beam can also be regarded as an antenna port set.
  • the embodiment of the beam in the NR protocol can be a spatial domain filter, or a spatial filter, or a spatial parameter (such as a spatial reception parameter and a spatial transmission parameter).
  • the beam used to transmit the signal can be called the transmission beam (transmission beam, Tx beam), also can be called the spatial domain transmission filter (spatial domain transmission filter), the spatial transmission filter (spatial transmission filter), the spatial domain transmission parameter (spatial domain) parameter) or spatial transmission parameter.
  • the beam used to receive the signal can be called the receive beam (reception beam, Rx beam), also can be called the spatial domain reception filter (spatial domain reception filter), the spatial reception filter (spatial reception filter), the spatial domain reception parameter (spatial domain) reception parameter) or spatial reception parameter.
  • Beamforming also known as precoding
  • the signal can be sent omnidirectionally or through a wider angle when using low or mid frequency bands.
  • the antenna size is generally based on 1/2 wavelength
  • the carrier frequency increases, the size of the antenna becomes smaller, which can be compared to the low frequency band in the same space.
  • an antenna array composed of many antenna elements can be arranged at the transmitting end and the receiving end.
  • the path loss and penetration loss become larger, and narrow beams can be formed by beamforming technology, and the formed narrow beams scan to cover the entire cell, thereby improving coverage, improving space division multiplexing, and reducing interference.
  • Improve spectral efficiency For example, Massive MIMO.
  • the beamforming technology adjusts the parameters of the basic unit of the phased array, so that signals at certain angles obtain constructive interference, while signals at other angles obtain destructive interference, thereby achieving signal enhancement at certain angles and directions.
  • Beamforming generates a directional beam, the beam is aimed at the target terminal equipment, and the transmitted signals of multiple antennas are coherently superimposed on the target terminal equipment, thereby improving the demodulation signal-to-noise ratio of the target terminal equipment and improving the user experience at the edge of the cell.
  • the beamforming weight varies with the wireless channel environment to ensure that the beam is always aimed at the target user.
  • the channel is reconstructed by using a precoding matrix at the transmitting end, and then beamforming is performed according to the reconstructed channel to generate a signal to be transmitted, thereby realizing spatial diversity and spatial multiplexing.
  • Spatial diversity is conducive to improving the reliability of signal transmission
  • spatial multiplexing is conducive to simultaneous transmission of multiple parallel data streams.
  • the precoding matrix needs to be well matched to the channel.
  • the determination of the precoding matrix may be determined by the terminal device side, and the precoding matrix determined by the terminal device is fed back to the network device. If the terminal device directly indicates each element in the precoding matrix to the network device through signaling, the signaling overhead will be relatively large. Therefore, in the current standard, the terminal device may send a precoding indicator (Matrix Indicator, PMI) to the network device, and the PMI may indicate an index of a precoding matrix, and each index corresponds to a precoding matrix in the codebook. Further, the network device may calculate the downlink reconstruction channel or reconstruction matrix according to the received precoding matrix fed back by the terminal device, and finally determine the precoding matrix for sending downlink signals.
  • PMI Precoding indicator
  • the network device may calculate the downlink reconstruction channel or reconstruction matrix according to the received precoding matrix fed back by the terminal device, and finally determine the precoding matrix for sending downlink signals.
  • a possible method may be a codebook-based method.
  • the terminal device measures the channel through a downlink channel state information reference signal (Channel State Information Reference Signal, CSI-RS), and feeds back an appropriate precoding matrix.
  • CSI-RS Channel State Information Reference Signal
  • Another possible way is to use a reference signal, for example, a sounding reference signal (SRS) to measure the uplink channel, through eigen beamforming (eigen beamforming, EBF), equal gain transmission (equal gain transmission, EGT) , maximal ratio transmission (MRT) and other algorithms for weighted calculation.
  • SRS sounding reference signal
  • the ordinal numbers such as “first” and “second” mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, sequence, priority or priority of multiple objects. Importance.
  • the first logo and the second logo are only used to distinguish different logos, but do not indicate the difference in content, priority, or importance of the two logos.
  • FIG. 1a shows a schematic diagram of a communication system suitable for the embodiment of the present application.
  • the communication system 100 includes a network device 101 and a terminal device 102.
  • the network device 101 may be configured with multiple antennas, and the terminal device may also be configured with multiple antennas.
  • the network device 101 may also include various components related to signal transmission and reception (eg, processors, modulators, multiplexers, demodulators or demultiplexers, etc.).
  • the network device 101 can communicate with a plurality of terminal devices (eg, the terminal device 102 shown in the figure).
  • the network device 101 may communicate with one or more terminal devices other than the terminal device 102 .
  • the terminal device 102 shown in FIG. 1a can communicate with the network device 102, but this only shows one possible scenario. In some scenarios, the terminal device 102 may also only have the network device 101 and other networks. Device communication, which is not limited in this application.
  • FIG. 1a is only a simplified schematic diagram for easy understanding, and the communication system may further include other network devices or may also include other terminal devices, which are not shown in FIG. 1a.
  • different base stations may be base stations with different identities, or may be base stations with the same identity that are deployed in different geographic locations. Before the base station is deployed, the base station does not know whether it will involve the scenarios applied by the embodiments of the present application. Therefore, the base station, or the baseband chip, should support the methods provided by the embodiments of the present application before deployment. It can be understood that, the aforementioned base stations with different identifiers may be base station identifiers, cell identifiers or other identifiers.
  • the embodiments of the present application may be applied to frequency division duplex and time division duplex scenarios, for example, MIMO scenarios.
  • ITU proposes three types of communication scenarios.
  • Enhanced Mobile Broadband mainly includes various consumer-oriented services, including web browsing, file download, text/voice/video chat, video, AR /VR, etc., the demand for high-speed services has increased, and the demand for network capacity has increased significantly.
  • MIMO can be used to improve the coverage gain of the traffic channel.
  • the embodiments of the present application may be specifically applied to, but not limited to, the following scenarios: a scenario in which a network device and a terminal device establish a beam pair.
  • the eNB applies multiple beams to transmit the synchronization signal to the UE, or the UE applies multiple beams to transmit the synchronization signal to the eNB.
  • the network device sends data to the terminal device, and the communication scenario is shown in Figure 1a.
  • the network device 101 can be a gNB, ng-eNB or eNB, and an LTE downlink (LTE DL) or a new radio downlink (NR DL) can be established between the network device 101 and the terminal device 102.
  • LTE DL LTE downlink
  • NR DL new radio downlink
  • the data links transmitted on the Uu port are called uplink and downlink, and the Uu port defines the communication protocol between the terminal equipment and the base station.
  • the Uu interface defines a transmission protocol similar to the uplink and downlink in the NR system, and basically follows the uplink and downlink transmission protocol of the NR system in terms of frequency band allocation, bandwidth, frame structure, transmission mode or signaling definition.
  • the terminal device may be a terminal device in a wireless communication system that has a wireless connection relationship with the network device.
  • the network device can implement the precoding solution based on the same technical solution with multiple terminal devices in the wireless communication system having a wireless connection relationship.
  • This application does not limit this.
  • Some scenarios in the embodiments of the present application are described by taking the scenario of an NR network in a wireless communication network as an example. It should be noted that the solutions in the embodiments of the present application may also be applied to other wireless communication networks, and the corresponding names may also be other The name of the corresponding function in the wireless communication network is substituted.
  • the method can be applied to a scenario where the base station sends a downlink reference signal to a terminal device.
  • the method may include:
  • Step 201 the network device sends reference signal configuration information to the terminal device.
  • the base station may first determine the information of the resource bearing the reference signal, and then send the reference signal configuration information to the terminal device.
  • the reference signal configuration information may specifically include information about resources bearing the reference signal.
  • the reference signal configuration information may include: the number P of symbols of the reference signal in a time slot, or the number of symbols of the reference signal in a time slot. index.
  • the reference signal configuration information may be configured through radio resource control (radio resource control, RRC) signaling, or media access control element (media access control element, MAC-CE), or downlink control information (downlink control information, DCI).
  • the reference signal configuration information may also include information such as conditions for reporting CSI.
  • the base station may send CSI reporting configuration and related information of CSI-RS resources to the UE.
  • the base station may configure reference signal configuration information for the UE through high-level signaling.
  • the reference signal configuration information may be a CSI report configuration (CSI report configuration), and each CSI report configuration includes a CSI report configuration ID (CSI report configuration ID). )Wait.
  • Step 202 the network device sends a reference signal to the terminal device.
  • the reference signal may be a CSI-RS signal.
  • Step 203 the terminal device generates measurement information according to the received reference signal, and sends the measurement information to the network device.
  • the terminal device After receiving the measurement configuration information, the terminal device receives the reference signal on the resource that bears the reference signal indicated by the measurement configuration information, measures the reference signal, and when the reporting condition indicated by the measurement configuration information is satisfied, the measurement configuration information configures the reference signal.
  • the terminal device can provide the base station with one of the number of layers (layer), precoding matrix, and modulation and coding scheme (Modulation and Coding Scheme, MCS) used for transmitting data for the base station, or variety.
  • MCS Modulation and Coding Scheme
  • RI is used to indicate the number of layers (layers) used for transmitting data
  • PMI is used to indicate the precoding matrix used for transmitting data, so as to support the transmission mode of the base station using space division multiplexing
  • CQI is used to indicate channel quality status information quantization results to support the base station in determining the appropriate MCS.
  • the terminal device can carry the CSI on the physical uplink shared channel (Physical Uplink Shared Channel, PUSCH) time-frequency resources, or the physical uplink control channel (Physical Uplink Control Channel, PUCCH) time-frequency resources.
  • PUSCH Physical Uplink Shared Channel
  • PUCCH Physical Uplink Control Channel
  • precoding may be understood as weighting a signal by using a precoding matrix, or may be understood as weighting a signal by using a precoding vector.
  • the precoding used by the reference signal is the same, which can be understood as the same transmission port of the reference signal.
  • the channel states of the channels corresponding to the signals sent by the same transmission port can be considered to be the same. It can be understood that the transmission ports of the reference signals are the same, and it can also be understood that the channel states of the reference signals are the same.
  • the second communication device may measure the reference signal, obtain a measurement result, and report the measurement to the first communication device result.
  • Step 204 the network device determines the reconstruction matrix according to the measurement information.
  • the network device may determine a reconstruction matrix based on the CSI report, so as to regard the reconstruction matrix as a precoding matrix used for beamforming, and generate a downlink signal to be sent to the terminal device.
  • the downlink signal may be precoded data weighted according to the reconstruction matrix, or the like.
  • the solid line represents the beam direction of the actual channel
  • the dashed line represents the beam direction of the reconstruction matrix used by the base station after CSI measurement, PMI feedback and channel reconstruction.
  • the beam direction of the weight used by the base station to send data will deviate from the beam direction of the actual channel, which will reduce the transmission rate of the user.
  • the II codebook that is, the precoding matrix is fed back in a way of feeding back some explicit channel information such as the channel covariance matrix
  • the precoding matrix's characterization accuracy of the actual channel is also constantly improving.
  • the terminal device supports the Type II codebook under the Release15 or 16 protocol as an example
  • using the Type II codebook under the Release15 or 16 protocol can reduce the quantization error caused by the precoding matrix.
  • the Type II codebook under the Release15 protocol only supports precoding matrix feedback with layers less than or equal to 2. Therefore, in the method for channel reconstruction based on PMI feedback, the base station cannot perform channel reconstruction with a rank greater than 2, and the accuracy is insufficient.
  • the Type II codebook under the Release16 protocol can feed back precoding matrices with 3 or 4 layers, considering the limitation of the resources occupied by the terminal equipment to feed back the CSI, the Type II codebook under the Release16 protocol can feed back the precoding matrix.
  • the quantization error of a precoding matrix with 3 or 4 layers is greater than that of a precoding matrix with 1 or 2 layers, resulting in insufficient reconstruction accuracy of a channel with a rank greater than 2.
  • FIG. 1a A schematic diagram of a scenario according to the embodiment of the present application as shown in FIG. 1a is used.
  • the terminal device 102 is connected to the network device 101 .
  • the network device 101 can reconstruct the downlink channel according to the precoding matrix fed back by the terminal device by using the precoding method provided in the embodiment of the present application.
  • the present application provides a method that uses weighted CSI-RS to perform multiple CSI measurements, and uses the precoding matrix fed back by the terminal equipment for multiple times.
  • FIG. 3 a schematic flowchart of a precoding method provided by an embodiment of the present application is shown. Referring to Figure 3, the method includes:
  • Step 301 The network device sends the ith reference signal to the terminal device.
  • the i-th reference signal is used for the terminal equipment to perform the i-th CSI measurement.
  • the i-th reference signal may be a weighted reference signal.
  • the network device sends the weighted reference signal to the terminal device based on the reference signal configuration information.
  • the base station uses a weighting matrix F i to weight the ith reference signal CSI-RS, and the weighting method is to multiply the weighting matrix and the ith reference signal CSI-RS, and transmit the ith reference signal CSI-RS through the downlink channel.
  • the terminal device receives the reference signal based on the reference signal configuration information.
  • Step 302 The terminal device determines the ith precoding matrix according to the received ith weighted reference signal.
  • Step 303 The terminal device feeds back the i-th measurement information to the network device.
  • the ith measurement information may include PMI information corresponding to the ith precoding matrix, and the PMI information is used to indicate an index of the ith precoding matrix.
  • the i-th measurement information may further include the rank of the i-th precoding matrix.
  • the precoding matrix in the terminal device may be pre-stored locally by the terminal device, or may be configured for the terminal device by the serving base station of the terminal device.
  • the precoding matrix in the network device may be pre-stored locally by the network device, which is not limited herein.
  • Steps 301-302 are repeated, and the network device receives N pieces of PMI information sent by the terminal device, thereby acquiring N precoding matrices obtained by N times of measurement by the terminal device.
  • a random matrix is used to weight the reference signal (eg, CSI-RS). Therefore, the downlink channel is reconstructed after acquiring the eigenvectors of the downlink channel corresponding to the PMI fed back by the UE for many times. Compared with the method of acquiring a single PMI, the accuracy of the reconstructed channel can be improved.
  • a randomly generated weighting matrix is used to weight the reference signal, which results in that the weighting matrices are not correlated with each other among the multiple CSI measurements of the UE. Therefore, there may be redundant precoding matrices corresponding to the PMIs fed back multiple times. remainder.
  • the feedback overhead in the case of a limited number of CSI measurements and feedbacks, it is not guaranteed to obtain a complete downlink channel.
  • the network device may generate a weighting matrix F N according to at least one precoding matrix fed back by the terminal device. For example, based on the scenario that the network device has sent N-1 reference signals and received N-1 precoding matrices obtained by the terminal device based on N-1 reference signal measurements, the network device can 1 precoding matrix, and determine the weighting matrix corresponding to the Nth reference signal. There can be many ways to generate the weighting matrix F N. Any reference signal in the N-1 reference signals can be expressed as the ith reference signal.
  • the precoding matrix fed back by the terminal device can be expressed as the ith precoding matrix. encoding matrix.
  • N-1 can be replaced by other characters, such as M, where M is a positive integer.
  • the implementation of the weighting matrix is exemplified by way a and way b below.
  • Mode a The weighting matrix corresponding to the Nth reference signal is orthogonal to the N-1 precoding matrices fed back corresponding to the first N-1 reference signals.
  • the mode a1 and the mode a2 are exemplified below.
  • the kth precoding matrix in the N precoding matrices fed back by the first N-1 CSI measurements may be represented as V k ,k ⁇ [1,N-1]. Represents the conjugate transpose matrix of the kth precoding matrix among the N precoding matrices.
  • the first matrix V c (N-1) composed of N-1 precoding matrices fed back by the first N-1 CSI measurements can be in multiple ways, such as combining, juxtaposing, and combining.
  • the first matrix V c (N-1) satisfies:
  • V c (N-1) [V 1 ,V 2 ,...V N-1 ]
  • mode a2 is used as an example to illustrate the weighting matrix used for the reference signal sent by each CSI measurement in the scenario of mode a.
  • the weighting matrix can satisfy:
  • N t is an N t -dimensional identity matrix, that is, the first reference signal sent is an unweighted reference signal, and N t represents the number of transmitting antennas of the network device.
  • the weighting matrix can satisfy:
  • the weighting matrix determined by the above method is an iterative matrix, and the weighting matrix F N used for the Nth reference signal is a conjugate symmetric matrix.
  • the N-1 precoding matrices are orthogonal to each other, and F N is in the null space of the space formed by V c (N-1).
  • Manner b At least one precoding matrix among the N-1 precoding matrices fed back is orthogonal to the weighting matrix.
  • the mode b there may also be multiple implementation modes, and the mode b1 and the mode b2 are exemplified below.
  • the kth precoding matrix in the N-1 precoding matrices fed back by the first N-1 CSI measurements may be represented as V k ,k ⁇ [1,N-1].
  • the precoding matrix orthogonal to the weighting matrix is denoted as V j , j ⁇ [1,M], where M is less than or equal to N-1.
  • M precoding matrices there may be M precoding matrices orthogonal to the weighting matrix.
  • the M precoding matrices may be arbitrarily selected from N-1 precoding matrices, or may be selected according to other information fed back by the terminal device. For example, according to the quality of the reference signal fed back by the terminal device, the M precoding matrices are determined. precoding matrix.
  • the method of selection is not limited in this application.
  • the first matrix V bM composed of M precoding matrices fed back by M times of CSI measurement can be in multiple ways, for example, combining, parallel, linear combination, and the like.
  • the first matrix V bM can satisfy:
  • V bM [V' 1 ,V' 2 ,...V' M ]
  • V' 1 , V' 2 ,...V' M may be one or more precoding matrices among the M precoding matrices, and M is an integer greater than or equal to 1.
  • the terminal device can perform channel estimation according to the received weighted reference signal, and calculate the equivalent channel of the Nth CSI measurement, and the equivalent channel can satisfy:
  • H represents the downlink channel between the network device and the terminal device
  • the dimension of H is N r ⁇ N t
  • N r represents the number of receiving antennas of the terminal device
  • N t represents the number of transmitting antennas of the network device.
  • the terminal device determines the equivalent channel according to the equivalent channel
  • the covariance matrix R N can satisfy:
  • the eigendecomposition of the covariance matrix R n can determine the unitary matrix U N after the eigendecomposition.
  • the unitary matrix U N satisfies:
  • U N is a unitary matrix composed of eigenvectors corresponding to the eigenvalues; ⁇ N is a diagonal matrix, and the diagonal elements are the eigenvalues of the covariance matrix R N.
  • the terminal device quantizes the matrix U N (:,1:v N ) composed of the eigenvectors corresponding to the first v N largest eigenvalues in ⁇ N , Thus, the corresponding precoding matrix V N is determined.
  • the precoding matrices V1 are orthogonal to each other, so that the eigenvectors corresponding to the reconstructed channel in the N-time precoding matrix reported by the terminal device can be approximately considered to be orthogonal to each other, which ensures the information reported by the terminal device. There is no redundancy, improving resource utilization.
  • the weighting matrix corresponding to the Nth reference signal is orthogonal to at least one of the N-1 precoding matrices fed back by the terminal device, the weighting matrix corresponding to the Nth reference signal is equal to
  • the M precoding matrices in the precoding matrices fed back N-1 times are orthogonal as an example, the precoding matrix V N determined by the terminal device according to the received weighting matrix F N is equivalent to the equivalent channel covariance A quantized representation of the eigenvector U N (:,1:v N ) of , at this time, the first matrix and the precoding matrix satisfy:
  • the precoding matrix V N of the Nth feedback is orthogonal to the M precoding matrices, wherein the M precoding matrices are orthogonal to the weighting matrix corresponding to the Nth reference signal.
  • the rank of the precoding matrix fed back by the terminal device is 2, and the first reference signal corresponds to the first precoding matrix fed back.
  • the weighting matrix of the second reference signal is orthogonally determined according to the first precoding matrix, and the second reference signal corresponds to the second precoding matrix fed back. Therefore, the first precoding matrix can be approximately considered to be the same as the second precoding matrix.
  • the precoding matrices are orthogonal.
  • the weighting matrix of the third reference signal may be orthogonally determined according to the second precoding matrix, and the third reference signal corresponds to the third precoding matrix fed back. At this time, the third precoding matrix can be approximately considered to be the same as The second precoding matrix is orthogonal.
  • the weighting matrix of the fourth reference signal may be determined according to the orthogonality of the second precoding matrix and the third precoding matrix, and the fourth reference signal corresponds to the fourth precoding matrix fed back.
  • the fourth The precoding matrix can be approximately considered to be orthogonal to the second precoding matrix and the third precoding matrix.
  • at least 6 linearly independent main eigenvectors can be determined (including the 2 eigenvectors corresponding to the first precoding matrix, the second precoding matrix corresponding to 2 eigenvectors of , and 2 eigenvectors corresponding to the fourth precoding matrix).
  • the method provides a more flexible way of determining the precoding matrix, and at the same time, the network device can reduce the feedback overhead and improve the accuracy of the reconstructed channel according to the precoding matrix fed back by the terminal device for a limited number of times.
  • Step 304 Determine a reconstruction matrix according to the N precoding matrices.
  • Mode C weighted average is performed according to multiple precoding matrices, so as to determine the reconstruction matrix.
  • mode C there may also be multiple implementation modes, and the mode C1-mode C4 is used as an example to illustrate below. It should be noted that, both of the methods a and b of the weighting matrix involved in the present application can be applied to the methods C1 and C2. Modes C3 and C4 can be applied to scenarios where the weighting matrix is Mode a.
  • the network device receives N precoding matrices corresponding to the N CSI measurements fed back by the terminal device, and the ith precoding matrix in the N precoding matrices may be represented as V i , i ⁇ [1,N].
  • the network device can multiply the received precoding matrix V i and the weighting matrix adopted for this measurement to determine the weighted precoding matrix V " i .
  • the weighting matrix as F i as an example, the weighted precoding matrix V " The encoding matrix V" i satisfies:
  • V” i F i V i
  • the intermediate variable W'' i For each weighted precoding matrix, the intermediate variable W'' i can be determined, a possible implementation, the intermediate variable W'' i satisfies:
  • the reconstructed downlink channel space covariance matrix Z is obtained.
  • the covariance matrix Z satisfies:
  • a i represents the weight coefficient of the intermediate variable calculated by the i-th CSI measurement, which can be set by the network device, which is not limited here.
  • a possible implementation can perform linear normalization to determine a i , for example, 0 ⁇ a i ⁇ 1, and satisfy
  • the network device performs eigendecomposition on the covariance matrix Z, thereby obtaining the matrix U a composed of the main eigenvectors after the eigendecomposition:
  • ⁇ a represents the eigenvalue after the eigendecomposition
  • U a represents the matrix composed of the main eigenvectors after the eigendecomposition. Represents the conjugate transpose matrix of the matrix composed of the principal eigenvectors after eigendecomposition. Therefore, U a can be directly used as a beamforming reconstruction matrix for transmitting downlink signals.
  • the intermediate variable Wi can be determined.
  • the intermediate variable Wi satisfies :
  • the N intermediate variables corresponding to the determined N precoding matrices can be weighted and averaged to obtain the reconstructed downlink channel spatial covariance matrix Z.
  • the covariance matrix Z satisfies:
  • 0 ⁇ i ⁇ 1 represents the weight coefficient of the intermediate variable calculated by the nth CSI measurement, and satisfies
  • the network device performs eigendecomposition on the covariance matrix Z, thereby obtaining the matrix U b composed of the main eigenvectors after the eigendecomposition:
  • ⁇ b represents the eigenvalue after the eigendecomposition
  • U b represents the matrix composed of the main eigenvectors after the eigendecomposition. Represents the conjugate transpose matrix of the matrix composed of the principal eigenvectors after eigendecomposition. Therefore, U b can be directly used as a beamforming reconstruction matrix for downlink signal transmission.
  • the precoding matrix fed back by the ith CSI measurement can be used as the ith eigenvector of the downlink channel H quantification.
  • the terminal device may also feed back the channel quality information CQI value c i to the network device, where the CQI value is used to represent the quantized value of the largest eigenvalue corresponding to the covariance matrix of the current CSI measurement.
  • the measurement information includes CQI.
  • it may also be reported with a rank indication (rank indication, RI), or may be reported separately, which is not limited here.
  • the CQI information fed back by the i-th CSI measurement can represent the quantized eigenvalues Then the spatial covariance of the downlink channel H satisfies:
  • the intermediate variable satisfies:
  • the network device receives the i-th precoding matrix V i and the CQI information c i among the N precoding matrices fed back by the terminal device, thereby determining the intermediate variable Wi and the weight coefficient c i , and performing a weighted average on them,
  • the reconstructed downlink channel spatial covariance Z satisfies:
  • the network device performs eigendecomposition on the covariance matrix Z, and the determined main eigenvector after the eigendecomposition can be used as the main eigenvector in the reconstruction matrix.
  • the precoding matrix can be more accurately weighted and averaged through the CQI information, which improves the accuracy of the reconstructed downlink channel main eigenvectors.
  • Mode C4 considering that when the number of precoding matrix layers fed back by the terminal device is greater than 1, the measurement information fed back by the terminal device does not include information about the estimated eigenvalues corresponding to the main eigenvectors of the downlink channel.
  • Combination mode a a possible implementation mode, before step 304, the terminal device may also feed back the diagonal matrix ⁇ N to the network device, where the diagonal elements in ⁇ N are the eigenvalues of the covariance matrix R N , and the rank is v N .
  • r is the rank of the downlink channel.
  • the network device receives the i-th precoding matrix V i and the diagonal matrix ⁇ i among the N precoding matrices fed back by the terminal device, and performs a weighted average on them to obtain the reconstructed downlink channel spatial covariance Z satisfies :
  • the network device performs eigendecomposition on the covariance matrix Z, and the determined main eigenvector after the eigendecomposition can be used as the main eigenvector in the reconstruction matrix.
  • the precoding matrix can be more accurately weighted and averaged through the diagonal matrix information, which improves the accuracy of the reconstructed downlink channel main eigenvectors.
  • Mode D the reconstruction matrix is determined according to multiple precoding matrices. Wherein, the number of eigenvectors in the reconstruction matrix is greater than the number of layers of the precoding matrix.
  • the mode D1-mode D2 is used as an example to illustrate. It should be noted that the above-mentioned method a of the weighting matrix in the present application is applicable to the method D1, and the above-mentioned method b of the weighting matrix is applicable to the method D2.
  • Mode D1 combined with mode a, in a scenario where the weighting matrix corresponding to the Nth reference signal and the N-1 precoding matrices fed back corresponding to the first N-1 reference signals are orthogonal to each other, in the reconstruction matrix determined by the network device, the The number of main feature vectors is greater than the number of layers of the precoding matrix.
  • the layers of the N precoding matrices can be linearly superimposed to obtain linearly independent eigenvectors in the reconstruction matrix.
  • the number of layers of the ith precoding matrix in the N precoding matrices is v i , i ⁇ [1,N], then the number of linearly independent feature vectors that can be determined by the network device can be That is, the rank of the reconstruction matrix can be Thus, the accuracy of the reconstruction matrix can be effectively improved.
  • the second matrix used to generate the reconstruction matrix can satisfy:
  • V d [V 1 ,V 2 ,...V N ]
  • the base station performs Schmitt orthogonalization on the matrix V d according to the second matrix to obtain the main eigenvector of the reconstructed downlink channel (ie, the eigenvector in the reconstructed matrix). Therefore, the orthogonalized matrix can be directly used as a beamforming reconstruction matrix for downlink signal transmission.
  • Mode D2 in combination with the above-mentioned mode b, in a scenario where at least one of the feedback N-1 precoding matrices is orthogonal to the weighting matrix, the number of main eigenvectors in the reconstruction matrix determined by the network device is greater than the number of precoding matrices The number of layers of the matrix.
  • the N precoding matrices fed back by the terminal equipment are partially orthogonal and can be partially complementary, therefore, if the N precoding matrices are Schmitt orthogonalized, K orthogonalized precoding matrices can be determined, where , the K orthogonalized precoding matrices are orthogonal to each other. At this time, the layers of the K orthogonalized precoding matrices can be linearly superimposed to obtain linearly independent eigenvectors in the reconstruction matrix.
  • the network device can determine the linearly independent eigenvectors of The number can be That is, the rank of the reconstruction matrix can be Thus, the accuracy of the reconstruction matrix can be effectively improved.
  • the second matrix used to generate the reconstruction matrix can satisfy:
  • V” d [V” 1 , V” 2 ,...V” K ]
  • V" i is the i-th orthogonalized precoding matrix among the K orthogonalized precoding matrices.
  • the network device can obtain the reconstructed downlink channel according to the matrix V" d
  • the principal eigenvectors of that is, the eigenvectors in the reconstruction matrix. Therefore, the orthogonalized matrix can be directly used as a beamforming reconstruction matrix for downlink signal transmission.
  • Step 401 The network device generates the first reference signal, and sends the first reference signal to the terminal device.
  • the weighting matrix F 1 corresponding to the first reference signal satisfies:
  • Step 402 The terminal device sends the indication information of the first precoding matrix to the network device.
  • the indication information of the first precoding matrix may be PMI information of the first precoding matrix.
  • the terminal equipment determines the equivalent channel of the first CSI measurement according to the first received reference signal Recalculate the covariance matrix
  • the covariance matrix R 1 is eigendecomposed to obtain a unitary matrix U 1 composed of eigenvectors; the terminal device quantizes the matrix composed of the first v 1 column vectors in U 1 to determine the first precoding matrix V 1 .
  • Step 403 The network device generates a second reference signal according to the first precoding matrix.
  • the network device generates the weighting matrix F 2 of the second CSI measurement according to the received V 1 feedback from the terminal device, where The second reference signal is generated by the weighting matrix F2.
  • Step 404 The terminal device sends the indication information of the second precoding matrix to the network device.
  • the indication information of the second precoding matrix may be PMI information of the second precoding matrix.
  • Step 405 The network device receives the two precoding matrices fed back by the terminal device, and determines the reconstruction matrix.
  • the second matrix is generated according to the two precoding matrices V 1 and V 2 .
  • the second matrix satisfies:
  • V d [V 1 ,V 2 ]
  • the network device performs Schmitt orthogonalization on the second matrix V d to obtain 2 main eigenvectors of the reconstructed downlink channel v 1 +v .
  • the orthogonalized matrix can be directly used as a beamforming reconstruction matrix for downlink signal transmission.
  • the layers of the precoding matrices can be superimposed linearly.
  • the determined reconstruction matrix can break through the limit of the protocol on the number of layers. , thereby effectively improving the accuracy of the reconstructed channel.
  • the limit of the codebook on the number of feedback precoding matrix layers is broken, and when the number of precoding matrix layers fed back is not greater than 2, the Type II codebook only uses at least two feedbacks.
  • the main eigenvectors of the downlink channel with the rank number of 3 or 4 can be completely obtained, thereby realizing the reconstruction of the downlink channel with the rank number of 3 or 4.
  • the number of layers of the precoding matrix that the terminal device can feed back to the network device is less than or equal to the preset number of restricted layers, and the network device determines the feature vector according to the N received precoding matrices Reconstruction matrix larger than the limit number of layers.
  • Step 501 The network device sets the i-th reference signal, and sends the i-th reference signal to the terminal device.
  • Step 502 The terminal device sends the indication information of the i-th precoding matrix to the network device.
  • the indication information of the ith precoding matrix may be the PMI information of the ith precoding matrix.
  • the network device may generate N reference signals.
  • the generation manner of the weighting matrix corresponding to the Nth reference signal may refer to the generation manner in manner b, which will not be repeated here.
  • the network device may receive the N precoding matrices sent by the terminal device.
  • the number of layers of the N precoding matrices is less than or equal to the number of restricted layers. For example, when the number of layers is limited to 3, the number of layers of the N precoding matrices may be 1, or 2, or 3.
  • Step 503 The network device determines the reconstruction matrix according to the N precoding matrices fed back by the terminal device.
  • the N precoding matrices are subjected to Schmitt orthogonalization to obtain K orthogonalized precoding matrices that are orthogonal to each other, and a second matrix is generated according to the K orthogonalized precoding matrices.
  • the second matrix satisfies:
  • V" d [V 1 , V 2 ,...V K ];
  • the network device performs Schmitt orthogonalization on the second matrix V'd to obtain the reconstructed downlink channel main eigenvectors.
  • the orthogonalized matrix can be directly used as a beamforming reconstruction matrix for downlink signal transmission.
  • the layers of the precoding matrices can be superimposed linearly.
  • the determined reconstruction matrix can break through the limit of the protocol on the number of layers. , thereby effectively improving the accuracy of the reconstructed channel.
  • mode C2-mode C4 and mode D1 combined with mode a, after the eigendecomposition of the covariance matrix of the downlink channel, it can be expressed as:
  • the unitary matrix after eigendecomposition which may be a matrix formed by the main eigenvectors of the downlink channel H. is a diagonal matrix, and the diagonal elements are the eigenvalues of the covariance matrix H H H and are arranged in descending order.
  • the N precoding matrices fed back by the terminal equipment can correspond to Quantization of the principal eigenvectors of .
  • the relationship between the precoding matrix obtained by each measurement and the downlink channel is illustrated below as an example.
  • the first precoding matrix V 1 fed back by the terminal equipment is a matrix composed of v 1 main eigenvectors of the downlink channel H
  • the weighting matrix F 2 satisfies:
  • the equivalent channel determined by the terminal device according to the second reference signal received The covariance matrix R 2 can satisfy:
  • the second precoding matrix V 2 is a quantized expression of the v 1 +1 to v 1 +v 2 eigenvectors of the downlink channel.
  • the terminal equipment determines the covariance matrix R i of the equivalent channel according to the received i-th reference signal to satisfy:
  • V i is A quantitative expression of the first v i eigenvectors, that is, during the i-th CSI measurement, the precoding matrix fed back by the terminal equipment can correspond to the v i features after removing the first ⁇ main eigenvectors from the downlink channel spatial covariance vector.
  • the precoding matrix fed back by the terminal equipment each time is complementary to the reconstruction matrix used to reconstruct the downlink channel, and there is no redundancy.
  • the terminal equipment needs no more than r times of CSI. measurement, the first r main eigenvectors of the downlink channel can be completely obtained.
  • the unitary matrix after eigendecomposition which may be a matrix formed by the main eigenvectors of the downlink channel H. is a diagonal matrix, and the diagonal elements are the eigenvalues of the covariance matrix H H H.
  • the N precoding matrices fed back by the terminal equipment can correspond to Quantization of the principal eigenvectors of .
  • the relationship between the precoding matrix obtained by each measurement and the downlink channel is illustrated below as an example.
  • the first precoding matrix V 1 fed back by the terminal equipment is the matrix formed by the first v 1 main eigenvectors of the downlink channel H Satisfy with the reconstruction matrix:
  • ai is the main eigenvector in the reconstruction matrix
  • the length of ai is N t , i ⁇ [1,r].
  • N t represents the number of transmitting antennas of the network device.
  • r is the rank of the reconstruction matrix.
  • the first precoding matrix V 1 b1
  • b1 corresponds to the first main eigenvector a1.
  • the length of b1 is N t .
  • N t represents the number of transmitting antennas of the network device.
  • the weighting matrix F 2 satisfies:
  • the equivalent channel determined by the terminal device according to the second reference signal received The covariance matrix R 2 can satisfy:
  • b2 may correspond to the main eigenvector a2 in the reconstruction matrix
  • b3 may correspond to the main eigenvector a3 in the reconstruction matrix
  • the lengths of b2 and b3 are respectively N t .
  • N t represents the number of transmitting antennas of the network device.
  • the second precoding matrix V 2 is a quantized expression of the v 1 +1 to v 1 +v 2 eigenvectors of the downlink channel.
  • the weighting matrix F 3 satisfies:
  • the second matrix V b2 [V 1 ].
  • b1 ⁇ F 3 0.
  • the terminal device determines the equivalent channel according to the third reference signal received
  • the covariance matrix R3 can satisfy:
  • the length of each feature vector of b4, b5, b6 is N t .
  • the eigenvectors a1 of the third precoding matrix V3 and the first precoding matrix are orthogonal to each other. Therefore, b4, b5, and b6 can correspond to the other three main eigenvectors in the reconstruction matrix except the main eigenvector a1, but , since V3 is not orthogonal to b2 and b3, there may be redundancy between the third precoding matrix V3 and the eigenvector b2 and the eigenvector b3.
  • the third precoding matrix V 3 is a quantized expression of the third eigenvectors from v 1 +1 to v 1 +v of the downlink channel.
  • V' 3 [b4', b5', b6']
  • the length of each feature vector of b4', b5', b6' is N t .
  • V 3 and b2, b3 are orthogonal to each other, therefore, b4', b5', b6' can correspond to the other three main eigenvectors in the reconstruction matrix except the main eigenvectors a2, a3, but, since V 3 and the first The eigenvectors b1 of the precoding matrix are not orthogonal, so there may be redundancy between the third precoding matrix V3 and the main eigenvector b1.
  • the third precoding matrix V 3 may be a quantized expression of the other v 3 eigenvectors of the downlink channel except the v 1 +1 th to v 1 +v 2 th eigenvectors.
  • the terminal equipment determines the covariance matrix R i of the equivalent channel according to the received i-th reference signal to satisfy:
  • v p represents the number of layers of each orthogonalized precoding matrix among the M orthogonalized precoding matrices determined after the i precoding matrices received by the network device are orthogonalized.
  • K1 orthogonalized precoding matrices can be determined, wherein the K1 orthogonalized precoding matrices are orthogonal to each other, at this time, K1 positive precoding matrices are
  • the layers of the interleaved precoding matrices can be linearly stacked to obtain linearly independent feature vectors in the reconstruction matrix.
  • the determined orthogonalized precoding matrices may be: V 1 , V 2 , V” 3 .
  • V ” 3 can be determined. 1 corresponds to 1 eigenvector, V 2 corresponds to 2 eigenvectors, and V" 3 is the eigenvector orthogonal to both V 1 and V 2 , that is, b1, b2 and b3 determined from [b4, b5, b6]
  • the eigenvectors are mutually orthogonal, including at least 1 eigenvector and at most 3 eigenvectors. Therefore, ⁇ is at least 4 and at most 6.
  • V i is A quantized expression of the vi eigenvectors in the i -th CSI measurement
  • the precoding matrix fed back by the terminal equipment can correspond to the downlink channel spatial covariance and remove the ⁇ corresponding to the precoding matrix orthogonal to the weighting matrix vi eigenvectors after the main eigenvector.
  • the precoding matrix fed back by the terminal equipment each time can be partially complementary to the reconstruction matrix used to reconstruct the downlink channel.
  • the downlink channel with a rank of r only a limited number of CSI measurements by the terminal equipment are required to obtain the complete downlink channel.
  • the first r principal eigenvectors of the channel Therefore, a complete channel space covariance matrix can be obtained under a limited number of measurements, thereby reducing quantization errors and improving beamforming accuracy.
  • FIG. 6 is a schematic block diagram of a communication apparatus 600 according to an embodiment of the present application.
  • the communication device 600 includes a processing module 601 and a transceiver module 602 .
  • the communication apparatus 600 may be a network device, or may be a chip applied in the network device, or other combined devices, components, etc., having the functions of the above-mentioned network device.
  • the transceiver module 602 may be a transceiver
  • the transceiver may include an antenna and a radio frequency circuit, etc.
  • the processing module 601 may be a processor, such as a baseband processor, and the baseband processor may include one or more Central processing unit (central processing unit, CPU).
  • CPU Central processing unit
  • the transceiver module 602 may be an input/output interface of a chip (eg, a baseband chip), and the processing module 601 may be a processor of the chip system, which may include one or more central processing units. It should be understood that the processing module 601 in this embodiment of the present application may be implemented by a processor or a circuit component related to the processor, and the transceiver module 602 may be implemented by a transceiver or a circuit component related to the transceiver.
  • processing module 601 may be configured to perform all operations performed by the network device in the embodiment shown in FIG. 2 or FIG. 3 except for the transceiving operations, and/or for other processes in support of the techniques described herein.
  • Transceiver module 602 may be used to perform all of the transceive operations performed by the network device in the embodiment shown in FIG. 2 or FIG. 3, and/or for other processes in support of the techniques described herein.
  • the transceiver module 602 may be a functional module, and the function module can perform both sending and receiving operations.
  • the transceiver module 602 may be used to execute the network device in the embodiment shown in FIG. 2 or FIG. 3 . All sending operations and receiving operations, for example, when performing a sending operation, the transceiver module 602 can be considered as a sending module, and when performing a receiving operation, the transceiver module 602 can be considered as a receiving module; or, the transceiver module 602 can also be two Functional modules, the transceiver module 602 can be regarded as a general term for these two functional modules, these two functional modules are respectively a sending module and a receiving module, the sending module is used to complete the sending operation, for example, the sending module can be used to execute Figure 2 or Figure 3 For all the sending operations performed by the network device in any of the shown embodiments, the receiving module is used to complete the receiving operation. For example, the receiving module may be used to perform the embodiment shown in FIG. 2 or FIG.
  • the processing module 601 is configured to determine a reconstruction matrix according to N precoding matrices, where the N precoding matrices include the N ⁇ 1 precoding matrices and the Nth precoding matrix; form a matrix to send downlink signals; the N-1 is a positive integer.
  • Transceiver module 602 configured to send N-1 reference signals to a terminal device; the network device receives, from the terminal device, indication information of N-1 precoding matrices corresponding to the N-1 reference signals; The terminal device sends the Nth reference signal, and the Nth reference signal is obtained by weighting with a weighting matrix, and the weighting matrix is orthogonal to at least one precoding matrix of the N-1 precoding matrices; The terminal device receives the indication information of the Nth precoding matrix corresponding to the Nth reference signal.
  • the weighting matrix F N of the Nth reference signal satisfies:
  • V c (N-1) represents the first matrix formed by the N-1 precoding matrices; represents the conjugate transpose matrix of the first matrix.
  • the first matrix satisfies:
  • V c (N-1) [V 1 ,V 2 ,...V N-1 ]
  • V k represents the kth precoding matrix in the N ⁇ 1 precoding matrices; the k ⁇ [1,N ⁇ 1]; the k is a positive integer.
  • the number of layers of the ith precoding matrix in the N precoding matrices is v i ; the ith precoding matrix in the N precoding matrices corresponds to the reconstruction matrix
  • the processing module 601 is specifically configured to determine the reconstruction matrix according to the weighted N precoding matrices.
  • the reconstruction matrix is determined according to the first covariance matrix Z1; the first covariance matrix Z1 satisfies:
  • 0 ⁇ i ⁇ 1, and ⁇ i represents the weight coefficient of the i-th precoding matrix in the N precoding matrices corresponding to the first covariance matrix;
  • the V i represents the ith precoding matrix in the N precoding matrices;
  • the Re represents the conjugate transpose matrix of the ith precoding matrix in the N precoding matrices;
  • the i ⁇ [1,N]; the i is a positive integer.
  • the processing module 601 is specifically configured to determine the reconstruction matrix according to a second matrix composed of N precoding matrices; the second matrix satisfies:
  • V c [V 1 ,V 2 ,...V N ]
  • V i represents the ith precoding matrix in the N precoding matrices; the i ⁇ [1,N]; the i is a positive integer.
  • the number of layers of the i-th precoding matrix in the N precoding matrices is 1;
  • the transceiver module 602 is further configured to receive a CQI value from the terminal device; the CQI value corresponds to the i-th i-th precoding matrix; the i ⁇ [1,N]; the i is positive Integer.
  • the reconstruction matrix is determined according to the second covariance matrix Z2; the second covariance matrix Z2 satisfies:
  • C i represents the CQI value corresponding to the ith reference signal
  • the Vi represents the ith precoding matrix in the N precoding matrices
  • the Re represents the conjugate transpose matrix of the ith precoding matrix in the N precoding matrices
  • the i ⁇ [1,N] represents the i is a positive integer.
  • an embodiment of the present application further provides a communication apparatus 700 .
  • the communication apparatus 700 may be used to implement the method performed by the network device in the above method embodiments, and reference may be made to the description in the above method embodiments, wherein the communication apparatus 700 may be a network device, or may be located in the network device, and may be an originating device.
  • the Communication device 700 includes one or more processors 701 .
  • the processor 701 may be a general-purpose processor or a special-purpose processor, or the like.
  • it may be a baseband processor, or a central processing unit.
  • the baseband processor may be used to process communication protocols and communication data
  • the central processing unit may be used to control communication devices (eg, network devices or chips, etc.), execute software programs, and process data of software programs.
  • the communication device 700 may include a transceiving unit to implement signal input (reception) and output (transmission).
  • the transceiver unit may be a transceiver, a radio frequency chip, or the like.
  • the communication apparatus 700 includes one or more processors 701, and the one or more processors 701 can implement the method performed by the network device in the above-described embodiments.
  • the processor 701 may also implement other functions in addition to implementing the methods in the above-described embodiments.
  • the processor 701 may execute a computer program, so that the communication apparatus 700 executes the method executed by the network device in the foregoing method embodiment.
  • the computer program may be stored in whole or in part in processor 701, such as computer program 703, or in memory 702 coupled to processor 701, in whole or in part, such as computer program 704, or by computer programs 703 and 704 jointly
  • the communication apparatus 700 is caused to perform the method performed by the network device in the foregoing method embodiments.
  • the communication apparatus 700 may also include a circuit, and the circuit may implement the functions performed by the network device in the foregoing method embodiments.
  • the communication device 700 may include one or more memories 702 on which a computer program 704 is stored, and the computer program can be executed on the processor, so that the communication device 700 executes the above method implementation The encoding method described in the example.
  • data may also be stored in the memory.
  • computer programs and/or data may also be stored in the processor.
  • the above-mentioned one or more memories 702 may store the associations or correspondences described in the above-mentioned embodiments, or related parameters or tables involved in the above-mentioned embodiments, and the like.
  • the processor and the memory can be provided separately, or can be integrated or coupled together.
  • the communication apparatus 700 may further include a transceiver unit 705 .
  • the processor 701 may be referred to as a processing unit, and controls the communication device (network device).
  • the transceiver unit 705 may be referred to as a transceiver, a transceiver circuit, or a transceiver, etc., and is used to implement the transceiver of data or control signaling.
  • the communication apparatus 700 may include a transceiver unit 705 .
  • the communication apparatus 700 may further include a transceiver unit 705 and an antenna 706 .
  • the processor 701 may be referred to as a processing unit, and controls the communication device (network device).
  • the transceiver unit 705 may be referred to as a transceiver, a transceiver circuit, or a transceiver, etc., and is used to implement the transceiver function of the device through the antenna 706 .
  • the transceiver unit 705 is configured to send N-1 reference signals to a terminal device; the network device receives N-1 precodings corresponding to the N-1 reference signals from the terminal device matrix indication information; send the Nth reference signal to the terminal device, where the Nth reference signal is obtained by weighting with a weighting matrix, the weighting matrix and at least one precoding matrix of the N-1 precoding matrices
  • the coding matrix is orthogonal; receiving from the terminal device the indication information of the Nth precoding matrix corresponding to the Nth reference signal;
  • a processor 701 configured to determine a reconstruction matrix according to N precoding matrices, where the N precoding matrices include the N ⁇ 1 precoding matrices and the Nth precoding matrix; according to the reconstruction matrix Send downlink signals; the N-1 is a positive integer.
  • the processor in this embodiment of the present application may be an integrated circuit chip, which has a signal processing capability.
  • each step of the above method embodiments may be completed by a hardware integrated logic circuit in a processor or a computer program in the form of software.
  • the above-mentioned processor may be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), an off-the-shelf programmable gate array (field programmable gate array, FPGA), or other possible solutions.
  • DSP digital signal processor
  • ASIC application specific integrated circuit
  • FPGA field programmable gate array
  • Programming logic devices discrete gate or transistor logic devices, discrete hardware components.
  • a general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
  • the method steps disclosed in conjunction with the embodiments of the present application may be directly embodied as executed by a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor.
  • the software modules may be located in random access memory, flash memory, read-only memory, programmable read-only memory or electrically erasable programmable memory, registers and other storage media mature in the art.
  • the storage medium is located in the memory, and the processor reads the information in the memory, and completes the steps of the above method in combination with its hardware.
  • the memory in this embodiment of the present application may be a volatile memory or a non-volatile memory, or may include both 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 programmable Erase programmable read-only memory (electrically EPROM, EEPROM) or flash memory.
  • Volatile memory may be random access memory (RAM), which acts as an external cache.
  • RAM random access memory
  • DRAM dynamic random access memory
  • SDRAM synchronous DRAM
  • SDRAM double data rate synchronous dynamic random access memory
  • ESDRAM enhanced synchronous dynamic random access memory
  • SLDRAM synchronous link dynamic random access memory
  • direct rambus RAM direct rambus RAM
  • Embodiments of the present application further provide a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a computer, implements the method of any of the foregoing method embodiments applied to a network device.
  • Embodiments of the present application further provide a computer program product, which implements the method of any of the above method embodiments applied to a network device when the computer program product is executed by a computer.
  • memory described herein is intended to include, but not be limited to, these and any other suitable types of memory.
  • the size of the sequence numbers of the above-mentioned processes does not mean the sequence of execution, and the execution sequence of each process should be determined by its functions and internal logic, and should not be dealt with in the embodiments of the present application. implementation constitutes any limitation.
  • the disclosed system, apparatus and method may be implemented in other manners.
  • the apparatus embodiments described above are only illustrative.
  • the division of units is only a logical function division.
  • there may be other division methods for example, multiple units or components may be combined or integrated. to another system, or some features can be ignored, or not implemented.
  • the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.
  • Units described as separate components may or may not be physically separated, and components shown as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit.
  • the functions, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer-readable storage medium.
  • the technical solution of the present application can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution.
  • the computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present application.
  • the aforementioned computer-readable storage medium can be any available medium that can be accessed by a computer.
  • the computer-readable medium may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (electrically erasable programmable read-only memory) read only memory, EEPROM), compact disc read-only memory (CD-ROM), universal serial bus flash disk (universal serial bus flash disk), removable hard disk, or other optical disk storage, disk storage A medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.
  • RAM random access memory
  • ROM read-only memory
  • EEPROM electrically erasable programmable read-only memory
  • CD-ROM compact disc read-only memory
  • universal serial bus flash disk universal serial bus flash disk
  • removable hard disk or other optical disk storage
  • disk storage A medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.

Abstract

本申请公开了一种预编码方法及装置，该方法包括：网络设备向终端设备发送N-1个参考信号；网络设备从终端设备接收N-1个参考信号对应的N-1个预编码矩阵的指示信息；网络设备向终端设备发送第N个参考信号，第N个参考信号是通过加权矩阵加权得到的，加权矩阵与N-1个预编码矩阵的至少一个预编码矩阵正交；网络设备从终端设备接收第N个参考信号对应的第N个预编码矩阵的指示信息；网络设备根据N个预编码矩阵确定重构矩阵，N个预编码矩阵包括N-1个预编码矩阵和第N个预编码矩阵；网络设备根据重构矩阵发送下行信号。

Description

一种预编码方法及装置 技术领域
本申请涉及通信技术领域，尤其涉及一种预编码方法及装置。
背景技术
在无线通信系统中，例如第四代(fourth generation,4G)和第五代(fifth generation,5G)无线通信系统——新无线接入技术(new radio access technology，NR)系统中，通过在基站侧布设大规模天线阵列(数十甚至数百根天线)，来同时服务覆盖小区内的多个用户，大规模多入多出(massive multiple input multiple output，massive MIMO)技术可以显著地提升系统的频谱效率和能量效率。例如，在massive MIMO系统进行下行传输时，基站(base station，BS)通常会进行波束赋形(也称为预编码)，此时，需要考虑信号到天线阵元之间映射的加权系数，这里的加权系数可以称为权值矩阵。通过权值矩阵可以调整各天线上发射单元的幅度和相位，使得信号向固定方向进行发送。
在5G系统中，预编码包括基于码本的传输模式和基于非码本的传输模式，其中基于码本的传输模式可以应用于频分双工(Frequency division duplex,FDD)和(Time division duplex，TDD)系统，而基于非码本的传输模式通常用于TDD系统中。在基于码本的传输模式中，终端从预先定义的码本集合中根据信道状态选择合适的码本，并通过控制信道向基站指示所选择的码本的索引。基站通过终端指示的码本的索引选择合适的预编码矩阵，以此为参考重构下行信道，确定出波束赋形所使用的权值矩阵。
考虑到反馈码本的索引的开销和预编码矩阵设计的复杂度，第三代合作伙伴计划(3rd Generation Partnership Project，3GPP)协议规定只能用码本中有限个离散的预编码矩阵去量化无限的、连续的信道波束方向，因此基站根据用户反馈的码本的索引进行信道重构以及波束赋形时，产生的量化误差会导致通过预编码矩阵确定的波束方向偏离实际信道的波束方向，使得用户传输速率显著降低。
发明内容
本申请提供一种预编码方法及装置，用于提高网络设备波束赋形的精度。
第一方面，本申请提供一种预编码方法，包括：网络设备向终端设备发送N-1个参考信号；所述网络设备从所述终端设备接收所述N-1个参考信号对应的N-1个预编码矩阵的指示信息；所述网络设备向所述终端设备发送第N个参考信号，所述第N个参考信号是通过加权矩阵加权得到的，所述加权矩阵与所述N-1个预编码矩阵的至少一个预编码矩阵正交；所述网络设备从所述终端设备接收所述第N个参考信号对应的第N个预编码矩阵的指示信息；所述网络设备根据N个预编码矩阵确定重构矩阵，所述N个预编码矩阵包括所述N-1个预编码矩阵和所述第N个预编码矩阵；所述网络设备根据所述重构矩阵发送下行信号；所述N-1为正整数。这里N-1可以替换成M，N可以替换成M+1，M为正整数。
通过上述方法网络设备根据终端设备反馈的预编码矩阵生成下一次发送的加权矩阵，例如，第N个参考信号采用的加权矩阵与终端设备反馈的N-1个预编码矩阵的至少一个预编码矩阵正交，从而，终端设备反馈的第N个预编码矩阵与之前反馈的N-1个预编码矩阵 的至少一个预编码矩阵正交，减少了预编码矩阵中的冗余信息，更好的反馈了信道特性，从而，网络设备可以根据该N个预编码矩阵生成重构矩阵，有效提高了重构矩阵描述信道特征的准确度，提高了波束赋形的精度。
一种可能的实现方式，所述加权矩阵F N满足：
Figure PCTCN2020106448-appb-000001
其中，V c(N-1)表示所述N-1个预编码矩阵组成的第一矩阵；
Figure PCTCN2020106448-appb-000002
表示所述第一矩阵的共轭转置矩阵。
通过上述方法，将第N个参考信号采用的加权矩阵与终端设备反馈的N-1个预编码矩阵都正交，从而，使得终端设备反馈的N个预编码矩阵没有冗余信息，并且，可以通过有限的反馈次数，实现重构信道所需的秩下的特征向量，有效提高了重构矩阵描述信道特征的准确度，提高了波束赋形的精度，并且有效降低了反馈预编码矩阵的开销及网络设备计算重构矩阵的计算量。
一种可能的实现方式，所述第一矩阵满足：
V c(N-1)＝[V 1,V 2,…V N-1]
其中，V k表示所述N-1个预编码矩阵中的第k个预编码矩阵；所述k∈[1,N-1]；所述k为正整数。
通过上述方法，通过合并N-1个预编码矩阵的方式生成第一矩阵，确定第一矩阵的复杂度较低，减少网络设备确定加权矩阵的计算量。
一种可能的实现方式，所述N个预编码矩阵中的第i个预编码矩阵的层数为v i；所述第i个预编码矩阵对应所述重构矩阵中的v i个特征向量；所述i∈[1,N]；所述i为正整数；所述v i为正整数。
通过上述方法，由于第N个参考信号采用的加权矩阵与终端设备反馈的N-1个预编码矩阵都正交，反馈的预编码矩阵可以对应相应层数个的特征向量，无需终端设备多次反馈，提高波束赋形的效率。
一种可能的实现方式，所述网络设备根据加权后的所述N个预编码矩阵，确定所述重构矩阵。
通过上述方法，预编码矩阵的秩与重构矩阵的秩可以相同，可以根据加权后的N个预编码矩阵确定重构矩阵，有效利用N个预编码矩阵中的信道特征，提高重构矩阵的精度。
一种可能的实现方式，所述重构矩阵为根据第一协方差矩阵Z1确定的；所述第一协方差矩阵Z1满足：
Figure PCTCN2020106448-appb-000003
其中，0＜λ i＜1，λ i表示N个预编码矩阵中的第i个预编码矩阵对应在所述第一协方差矩阵中的权重系数；
Figure PCTCN2020106448-appb-000004
所述V i表示所述N个预编码矩阵中的第i个预编码矩阵；所述
Figure PCTCN2020106448-appb-000005
表示所述N个预编码矩阵中的第i个预编码矩阵的共轭转置矩阵；所述i∈[1,N]；所述i为正整数。
通过上述方法，根据N个预编码矩阵确定第一协方差矩阵，从而对第一协方差矩阵进行加权归一化，从而，有效利用N个预编码矩阵中的信道特征，提高重构矩阵的精度。
一种可能的实现方式，所述网络设备根据N个预编码矩阵组成的第二矩阵，确定所述重构矩阵；所述第二矩阵满足：
V c＝[V 1,V 2,…V N]
其中，V i表示所述N个预编码矩阵中的第i个预编码矩阵；所述i∈[1,N]；所述i为正整数。
通过上述方法，N个预编码矩阵的秩可以与重构矩阵的秩不同，可以根据不同的预编码矩阵的层数，及重构矩阵所需的特征向量的个数，确定终端设备需反馈的预编码矩阵的次数，重构矩阵的秩不限于反馈的预编码矩阵的秩，可以提高重构矩阵的适应性。
一种可能的实现方式，所述N个预编码矩阵中的第i个预编码矩阵的层数为1；所述网络设备接收来自所述终端设备的所述第i个参考信号对应的信道质量信息(channel quality information，CQI)值；所述i∈[1,N]；所述i为正整数。
通过上述方法，在预编码矩阵的层数为1时，终端设备反馈的预编码矩阵可以对应1个重构矩阵中的特征向量，从而，根据反馈的CQI值，作为该特征向量的特征值，进一步提供了信道的特征，有利于网络设备获得更准确的重构矩阵，提高波束赋形的精度。
一种可能的实现方式，所述重构矩阵为根据第二协方差矩阵Z2确定的；所述第二协方差矩阵Z2满足：
Figure PCTCN2020106448-appb-000006
其中，C i表示所述第i个参考信号对应的CQI值；所述V i表示所述N个预编码矩阵中的第i个预编码矩阵；所述
Figure PCTCN2020106448-appb-000007
表示所述N个预编码矩阵中的第i个预编码矩阵的共轭转置矩阵；所述i∈[1,N]；所述i为正整数。
通过上述方法，终端设备反馈的预编码矩阵可以对应1个重构矩阵中的特征向量，从而，根据反馈的CQI值，作为该特征向量的特征值，作为加权预编码矩阵中的权值，有利于网络设备获得更准确的重构矩阵，提高波束赋形的精度。
第二方面，本申请提供一种通信装置，例如该通信装置为如前的网络设备。通信装置用于执行上述第一方面或任一可能的实施方式中的方法。具体地，通信装置可以包括用于执行第一方面或任一可能的实施方式中的方法的模块，例如包括处理模块和收发模块。示例性地，收发模块可以包括发送模块和接收模块，发送模块和接收模块可以是不同的功能模块，或者也可以是同一个功能模块，但能够实现不同的功能。示例性地，通信装置为通信设备，或者为设置在通信设备中的芯片或其他部件。示例性地，通信设备为网络设备。例如，收发模块也可以通过收发器实现，处理模块也可以通过处理器实现。或者，发送模块可以通过发送器实现，接收模块可以通过接收器实现，发送器和接收器可以是不同的功能模块，或者也可以是同一个功能模块，但能够实现不同的功能。如果通信装置为通信设备，收发器例如通过通信设备中的天线、馈线和编解码器等实现。或者，如果通信装置为设置在通信设备中的芯片，那么收发器(或，发送器和接收器)例如为芯片中的通信接口，该通信接口与通信设备中的射频收发组件连接，以通过射频收发组件实现信息的收发。
关于第二方面或第二方面的各种可选的实施方式所带来的技术效果，可参考对于第一方面或第一方面的各相应的可能的实现方式的技术效果的介绍。
第三方面，提供一种通信装置，该通信装置例如为如前的网络设备。该通信装置包括 处理器和通信接口，通信接口可用于与其他装置或设备进行通信。可选的，该通信装置还可以包括存储器，用于存储计算机指令。处理器和存储器相互耦合，用于实现上述第一方面或各种可能的实施方式所描述的方法。或者，通信装置也可以不包括存储器，存储器可以位于通信装置外部。处理器、存储器和通信接口相互耦合，用于实现上述第一方面或各种可能的实施方式所描述的方法。例如，当处理器执行存储器存储的计算机指令时，使通信装置执行上述第一方面或任意一种可能的实施方式中的方法。示例性地，通信装置为通信设备，或者为设置在通信设备中的芯片或其他部件。示例性的，通信设备为网络设备。其中，如果通信装置为通信设备，通信接口例如通过通信设备中的收发器(或者，发送器和接收器)实现，例如收发器通过通信设备中的天线、馈线和编解码器等实现。或者，如果通信装置为设置在通信设备中的芯片，那么通信接口例如为芯片的输入/输出接口，例如输入/输出管脚等，该通信接口与通信设备中的射频收发组件连接，以通过射频收发组件实现信息的收发。
第四方面，提供一种芯片，所述芯片系统包括至少一个处理器和收发器，所述收发器和所述至少一个处理器通过线路互联，所述处理器通过运行指令，以执行执行上述第一方面或任一可能的实施方式中的方法。
第五方面，提供一种计算机可读存储介质，计算机可读存储介质用于存储计算机程序，当计算机程序在计算机上运行时，使得计算机执行上述第一方面或任意一种可能的实施方式中的方法。
第六方面，提供一种包含指令的计算机程序产品，计算机程序产品用于存储计算机程序，当计算机程序在计算机上运行时，使得计算机执行上述第一方面的任意一种可能的实施方式中的方法。
附图说明
图1a为适用于本申请实施例的场景示意图；
图1b为适用于本申请实施例的场景示意图；
图2为本申请实施例提供的一种预编码方法流程示意图；
图3为本申请实施例提供的一种预编码方法流程示意图；
图4为本申请实施例提供的一种预编码方法流程示意图；
图5为本申请实施例提供的一种预编码方法流程示意图；
图6为本申请实施例提供的一种通信装置的结构示意图；
图7为本申请实施例提供的一种通信装置的结构示意图。
具体实施方式
下面将结合附图，对本申请实施例进行详细描述。
本申请提供的预编码方法可以应用于各类通信系统中，本申请提供的通信系统例如可以是支持4G接入技术的长期演进(long term evolution，LTE)系统，5G接入技术的新无线(new radio，NR)系统，任何与第三代合作伙伴计划(3rd generation partnership project，3GPP)相关的蜂窝系统，无线保真(wireless-fidelity，WiFi)系统，全球微波互联接入(worldwide interoperability for microwave access，WiMAX)系统，多无线接入技术(Radio Access Technology,RAT)系统，或者其他面向未来的通信技术。例如，可以是物联网(internet of  things，IoT)系统、窄带物联网(narrow band internet of things，NB-IoT)系统、长期演进(long term evolution，LTE)系统，也可以是第五代(5G)通信系统，还可以是LTE与5G混合架构、也可以是NR系统，以及未来通信发展中出现的新的通信系统等。本申请适用于5G NR频分双工(Frequency Division Duplexing，FDD)MIMO系统，5G NR时分双工(Time Division Duplexing，TDD)MIMO系统。
以下，对本申请实施例中的部分用语进行解释说明，以便于本领域技术人员理解。
1)终端设备，包括向用户提供语音和/或数据连通性的设备，例如可以包括具有无线连接功能的手持式设备、或连接到无线调制解调器的处理设备。该终端设备可以经无线接入网(radio access network，RAN)与核心网进行通信，与RAN交换语音和/或数据。本申请中终端是具有无线收发功能的设备，可以部署在陆地上，包括室内或室外、手持、穿戴或车载；也可以部署在水面上(如轮船等)；还可以部署在空中(例如无人机、飞机、气球和卫星上等)。终端可以是手机(mobile phone)、平板电脑(Pad)、带无线收发功能的电脑、虚拟现实(virtual reality，VR)终端设备、增强现实(augmented reality，AR)终端设备、工业控制(industrial control)中的无线终端、无人驾驶(self driving)中的无线终端、远程医疗(remote medical)中的无线终端、智能电网(smart grid)中的无线终端、运输安全(transportation safety)中的无线终端、智慧城市(smart city)中的无线终端、智慧家庭(smart home)中的无线终端等等。本申请的实施例对应用场景不做限定。终端有时也可以称为终端设备、用户设备(user equipment，UE)、接入终端设备、站、UE单元、UE站、移动站、移动台、远方站、远程终端设备、移动设备、UE终端设备、终端设备、无线通信设备、UE代理或UE装置、或某种其他合适的术语。终端也可以是固定的或者移动的。该终端设备可以包括车辆(vehicle)，车载模块(vehicle module)、用户设备(user equipment，UE)、无线终端设备、移动终端设备、订户单元(subscriber unit)、订户站(subscriber station)，移动站(mobile station)、移动台(mobile)、远程站(remote station)、接入点(access point，AP)、远程终端设备(remote terminal)、接入终端设备(access terminal)、用户终端设备(user terminal)、用户代理(user agent)、或用户装备(user device)等。例如，可以包括移动电话(或称为“蜂窝”电话)，具有移动终端设备的计算机，便携式、袖珍式、手持式、计算机内置的或者车载的移动装置，智能穿戴式设备等。例如，个人通信业务(personal communication service，PCS)电话、无绳电话、会话发起协议(session initiation protocol，SIP)话机、无线本地环路(wireless local loop，WLL)站、个人数字助理(personal digital assistant，PDA)、等设备。还包括受限设备，例如功耗较低的设备，或存储能力有限的设备，或计算能力有限的设备等。例如包括条码、射频识别(radio frequency identification，RFID)、传感器、全球定位系统(global positioning system，GPS)、激光扫描器等信息传感设备。
作为示例而非限定，在本申请实施例中，该终端设备还可以是可穿戴设备。可穿戴设备也可以称为穿戴式智能设备，是应用穿戴式技术对日常穿戴进行智能化设计、开发出可以穿戴的设备的总称，如眼镜、手套、手表、服饰及鞋等。可穿戴设备即直接穿在身上，或是整合到用户的衣服或配件的一种便携式设备。可穿戴设备不仅仅是一种硬件设备，更是通过软件支持以及数据交互、云端交互来实现强大的功能。广义穿戴式智能设备包括功能全、尺寸大、可不依赖智能手机实现完整或者部分的功能，例如：智能手表或智能眼镜等，以及只专注于某一类应用功能，需要和其它设备如智能手机配合使用，如各类进行体 征监测的智能手环、智能头盔、智能首饰等。
本申请实施例的终端设备还可以是作为一个或多个部件或者单元而内置于车辆的车载模块、车载模组、车载部件、车载芯片或者车载单元，车辆通过内置的所述车载模块、车载模组、车载部件、车载芯片或者车载单元可以实施本申请实施例的方法。
2)网络设备
网络设备为具有无线收发功能的设备或可设置于该设备的芯片，该设备包括但不限于：演进型节点B(evolved Node B，eNB)、无线网络控制器(radio network controller，RNC)、节点B(Node B，NB)、基站控制器(base station controller，BSC)、基站收发台(base transceiver station，BTS)、家庭基站(例如，home evolved NodeB，或home Node B，HNB)、基带单元(baseband unit，BBU)，无线保真(wireless fidelity，WIFI)系统中的接入点(access point，AP)、无线中继节点、无线回传节点、传输点(transmission and reception point，TRP或者transmission point，TP)等，还可以为5G，如，NR，系统中的gNB，或，传输点(TRP或TP)，5G系统中的基站的一个或一组(包括多个天线面板)天线面板，或者，还可以为构成gNB或传输点的网络节点，如基带单元(BBU)，或，分布式单元(DU，distributed unit)等。
在一些部署中，gNB可以包括集中式单元(centralized unit，CU)和DU。gNB还可以包括射频单元(radio unit，RU)。CU实现gNB的部分功能，DU实现gNB的部分功能，比如，CU实现无线资源控制(radio resource control，RRC)，分组数据汇聚层协议(packet data convergence protocol，PDCP)层的功能，DU实现无线链路控制(radio link control，RLC)、媒体接入控制(media access control，MAC)和物理(physical，PHY)层的功能。由于RRC层的信息最终会变成PHY层的信息，或者，由PHY层的信息转变而来，因而，在这种架构下，高层信令，如RRC层信令或PHCP层信令，也可以认为是由DU发送的，或者，由DU+RU发送的。可以理解的是，网络设备可以为CU节点、或DU节点、或包括CU节点和DU节点的设备。此外，CU可以划分为接入网RAN中的网络设备，也可以将CU划分为核心网CN中的网络设备，在此不做限制。
(3)波束(beam)
波束是一种通信资源。波束可以是宽波束，或者窄波束，或者其他类型波束。不同的波束可以认为是不同的资源(该资源可以是空间域资源)。形成波束的技术可以是波束赋形技术或者其他技术手段。波束赋形技术可以具体为数字波束赋形技术，模拟波束赋形技术，混合数字/模拟波束赋形技术。通过不同的波束可以发送相同的信息或者不同的信息。可选的，可以将具有相同或者类似的通信特征的多个波束视为是一个波束。一个波束可以通过一个或多个天线端口发送，该波束用于传输数据信道，控制信道和探测信号等，例如，信号经波束发射出去后，在空间不同方向上可以形成的信号强度的分布，。可以理解的是，形成一个波束的一个或多个天线端口也可以看作是一个天线端口集。
波束在NR协议中的体现可以是空域滤波器(spatial domain filter)，或者称空间滤波器(spatial filter)，或称空间参数(spatial parameter)(如空间接收参数，和空间发送参数)。用于发送信号的波束可以称为发送波束(transmission beam，Tx beam)，也可以称为空域发送滤波器(spatial domain transmission filter)，空间发送滤波器(spatial transmission filter)，空域发送参数(spatial domain parameter)或空间发送参数(spatial transmission parameter)。用于接收信号的波束可以称为接收波束(reception beam，Rx beam)，也可以称为空域接收 滤波器(spatial domain reception filter)，空间接收滤波器(spatial reception filter)，空域接收参数(spatial domain reception parameter)或空间接收参数(spatial reception parameter)。
4)波束赋形(也称为预编码)
在大多数情况下，根据无线波的物理特性，在使用低频或中频频段时，可以全向发送信号或者通过一个较宽的角度来发送信号。然而，当使用高频频段的情况下，特别是非常高的高频频段，由于天线尺寸一般基于1/2波长，在载波频率提高时，天线的尺寸变小，相比低频段同样空间下可容纳更多天线，可以在发送端和接收端布置很多天线阵子构成的天线阵列。另外，由于载波频率的提高，路径损耗和穿透损耗变大，可以通过波束赋形技术形成窄波束，形成的窄波束扫描覆盖整个小区，从而可以提升覆盖、提升空分复用、降低干扰，提升频谱效率。例如，Massive MIMO。
波束赋形技术通过调整相位阵列的基本单元的参数，使得某些角度的信号获得相长干涉，而另一些角度的信号获得相消干涉，从而实现某些角度和方向的信号增强。波束赋形产生具有方向性的波束，波束对准目标终端设备，同时多天线的发射信号在目标终端设备相干叠加，从而提高目标终端设备的解调信噪比，改善小区边缘的用户体验。波束赋形权值随无线信道环境变化而变化，以保证波束时刻对准目标用户。
在MIMO传输中，通过在发送端采用预编码矩阵对信道进行重构，进而根据重构的信道进行波束赋形，以生成待发送的信号，从而实现空间分集和空间复用。空间分集有利于信号传输的可靠性的提高，而空间复用有利于同时传输多个并行的数据流。无论是对于空间分集还是空间复用，都需要预编码矩阵能很好地匹配信道。
在下行基于码本的传输中，预编码矩阵的确定可以由终端设备侧确定，并向网络设备反馈终端设备确定的预编码矩阵。如果终端设备通过信令向网络设备直接指示预编码矩阵里的每个元素，则信令的开销会比较大。因此，当前标准中，终端设备可以向网络设备发送预编码指示(Matrix Indicator，PMI)，PMI可以指示预编码矩阵的索引，每个索引对应码本中的一个预编码矩阵。进一步的，网络设备可以根据接收到的终端设备反馈的预编码矩阵，计算下行重构信道或重构矩阵，并最终确定用于发送下行信号的预编码矩阵。
波束赋形获取重构矩阵的方式可以包括多种。举例来说，一种可能的方式，可以是基于码本的方式，终端设备通过下行信道状态信息参考信号(Channel State Information Reference Signal，CSI-RS)测量信道，并反馈合适的预编码矩阵。另一种可能的方式，可以利用参考信号，例如，探测参考信号(sounding reference signal，SRS)测量上行信道，通过特征波束赋形(eigen beamforming，EBF)，等增益传输(equal gain transmission，EGT)，最大比例传输(maximal ratio transmission，MRT)等算法进行加权计算。
5)本申请实施例中的术语“系统”和“网络”可被互换使用。“至少一个”是指一个或者多个，“多个”是指两个或两个以上。“和/或”，描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B的情况，其中A,B可以是单数或者复数。字符“/”一般表示前后关联对象是一种“或”的关系。“以下至少一项(个)”或其类似表达，是指的这些项中的任意组合，包括单项(个)或复数项(个)的任意组合。例如，a,b,或c中的至少一项(个)，可以表示：a,b,c,a-b,a-c,b-c,或a-b-c，其中a,b,c可以是单个，也可以是多个。
以及，除非有相反的说明，本申请实施例提及“第一”、“第二”等序数词是用于对多个对象进行区分，不用于限定多个对象的顺序、时序、优先级或者重要程度。例如，第一 标识和第二标识，只是为了区分不同的标识，而并不是表示这两种标识的内容、优先级或者重要程度等的不同。
为便于理解本申请实施例，首先以图1a中示出的通信系统为例详细说明适用于本申请实施例的通信系统。图1a示出了适用于本申请实施例的通信系统的示意图。如图1a所示，该通信系统100包括网络设备101和终端设备102，网络设备101可配置有多个天线，终端设备也可配置有多个天线。应理解，网络设备101还可包括与信号发送和接收相关的多个部件(例如，处理器、调制器、复用器、解调器或解复用器等)。
在该通信系统100中，网络设备101可以与多个终端设备(例如图中示出的终端设备102)通信。网络设备101可以与除了终端设备102以外的一个或多个终端设备通信。但应理解，图1a中示出的终端设备102可与网络设备102通信，但这仅示出了一种可能的场景，在某些场景中，终端设备102还可能仅网络设备101和其他网络设备通信，本申请对此不做限定。
应理解，图1a仅为便于理解而示例的简化示意图，该通信系统中还可以包括其他网络设备或者还可以包括其他终端设备，图1a中未予以画出。本申请实施例中不同基站可以为具有不同的标识的基站，也可以为具有相同的标识的被部署在不同地理位置的基站。由于在基站被部署前，基站并不会知道其是否会涉及本申请实施例所应用的场景，因而，基站，或基带芯片，都应在部署前就支持本申请实施例所提供的方法。可以理解的是，前述具有不同标识的基站可以为基站标识，也可以为小区标识或者其他标识。
本申请实施例可以应用于频分双工和时分双工的场景，例如，MIMO的场景。例如，在未来的IMT系统中，ITU提出了三大类通信场景，其中，Enhanced Mobile Broadband主要包括各种面向消费者的业务，包括网页浏览、文件下载、文字/语音/视频聊天、视频、AR/VR等等，高速率业务需求的增加，及网络容量的需求大幅增加。此时，可以采用MIMO，以提高业务信道的覆盖增益。示例性，本申请实施例具体可以应用但不限于以下场景：网络设备与终端设备建立波束对的场景。例如，eNB应用多个波束向UE发送同步信号，或者UE应用多个波束向eNB发送同步信号。
在下行传输场景中，网络设备向终端设备发送数据，通信场景如图1a所示。在图1a中，网络设备101可以为gNB、ng-eNB或eNB，网络设备101与终端设备102之间可以建立LTE的下行链路(LTE DL)或者新无线的下行链路(NR DL)。在Uu口传输的数据链路被称为上行链路和下行链路，Uu口定义了终端设备和基站之间的通信协议。Uu口定义了类似于NR系统中的上下行的传输协议，在频段分配、带宽、帧结构、传输模式或信令定义等方面基本沿用NR系统的上下行传输协议。
以下，不失一般性，以一个终端设备与网络设备之间的交互过程为例详细说明本申请实施例，该终端设备可以为处于无线通信系统中与网络设备具有无线连接关系的终端设备。可以理解的是，网络设备可以与处于该无线通信系统中的具有无线连接关系的多个终端设备基于相同的技术方案来实现预编码的方案。本申请对此并不做限定。本申请实施例中部分场景以无线通信网络中NR网络的场景为例进行说明，应当指出的是，本申请实施例中的方案还可以应用于其他无线通信网络中，相应的名称也可以用其他无线通信网络中的对应功能的名称进行替代。
下面结合附图对本申请实施例提供预编码的方法进行具体说明。其中，该方法可以应用于基站向终端设备发送下行参考信号的场景中。如图2所示，该方法可以包括：
步骤201，网络设备向终端设备发送参考信号配置信息。
在NR系统中，支持终端设备向基站上报信道状态信息(Channel State Information，CSI)。具体的，基站可以先确定承载参考信号的资源的信息后，向终端设备发送参考信号配置信息。参考信号配置信息具体可以包括承载参考信号的资源的信息，示例性的，参考信号配置信息可以包括：参考信号在一个时隙内的符号个数P、或者参考信号在一个时隙内的符号的索引。参考信号配置信息可以是通过无线资源控制(radio resource control，RRC)信令，或者媒体介入控制控制单元(media access control element，MAC-CE)，或者下行控制信息(downlink control information，DCI)配置。
参考信号配置信息还可以包括上报CSI的条件等信息。例如，基站可以向UE发送CSI上报配置和CSI-RS资源的相关信息。其中，基站可以通过高层信令为UE配置参考信号配置信息，例如，参考信号配置信息可以为CSI上报配置(CSI report configuration)，每个CSI上报配置中包含CSI上报配置识别号(CSI report configuration ID)等。
步骤202，网络设备向终端设备发送参考信号。
其中，参考信号可以为CSI-RS信号。
步骤203，终端设备根据接收的参考信号生成测量信息，并将测量信息发送至网络设备。
终端设备接收测量配置信息后，在测量配置信息所指示的承载参考信号的资源接收参考信号，对参考信号进行测量，并在满足测量配置信息所指示的上报条件时，在测量配置信息所配置的用于发送CSI的资源，向网络设备发送CSI。
终端设备可以通过上报测量信息(例如，CSI)，为基站提供发送数据所使用的层数(layer)，预编码矩阵，和调制和编码方案(Modulation and Coding Scheme，MCS)等中的一种或者多种。其中，RI用于指示传输数据所使用的层数(layer)；PMI用于指示传输数据所使用的预编码矩阵，以支持基站采用空分复用的发送方式；CQI用于指示信道质量状态信息的量化结果，以支持基站确定合适的MCS。
终端设备可以将CSI承载在物理上行共享信道(Physical Uplink Shared Channel，PUSCH)时频资源上，或者物理上行链路控制信道(Physical Uplink Control Channel，PUCCH)时频资源上。
需要说明的是，本申请中，预编码可以理解为采用预编码矩阵对信号进行加权，或者可以理解为采用预编码向量对信号进行加权。参考信号采用的预编码相同，可以理解为参考信号的发送端口相同。一般情况下，相同发送端口发送的信号所对应信道的信道状态可以认为是相同的，可以理解的，参考信号的发送端口相同，还可以理解为参考信号的信道状态相同。
在一种可能的实施方式中，第二通信设备在接收第一通信设备发送的参考信号后，第二通信设备可以对该参考信号进行测量，得到测量结果，并向第一通信设备上报该测量结果。
步骤204，网络设备根据测量信息，确定重构矩阵。
其中，网络设备可以基于CSI报告，确定重构矩阵，从而将重构矩阵看作波束赋形所使用的预编码矩阵，生成向终端设备发送的下行信号。下行信号可以是根据重构矩阵进行加权后的预编码数据等。
如图1b所示，实线代表实际信道的波束方向，虚线代表基站经过CSI测量、PMI反馈和信道重构后使用的重构矩阵的波束方向。
由于量化误差的影响，基站发送数据使用的权值的波束方向会偏离实际信道的波束方向，这会使得用户传输速率有所下降。随着码本类型和标准协议的不断演进，从3GPP的发布版本Release15到发布版本Release16协议，从类型I码本(即基于码本的PMI等隐含信道信息的方式反馈预编码矩阵)到类型II码本(即以反馈信道协方差矩阵等部分显性信道信息的方式反馈预编码矩阵)，预编码矩阵对实际信道的刻画精度也在不断提高。以终端设备支持Release15或者16协议下类型II码本的无线通信场景为例，使用Release15或者16协议下类型II码本可以使得由预编码矩阵带来的量化误差有所下降。Release15协议下的类型II码本仅支持层数小于或等于2的预编码矩阵反馈，因此，对于根据PMI反馈进行信道重构的方法中，基站不能进行秩数大于2的信道重构，精度不足。另外，虽然Release16协议下的类型II码本，可以反馈层数为3或4的预编码矩阵，但是考虑到终端设备反馈CSI的占用的资源的限制，Release16协议下的类型II码本，在反馈层数为3或4的预编码矩阵时的量化误差大于层数为1或2的预编码矩阵，导致秩数大于2的信道重构精度不足。
结合如图1a所示的本申请实施例的一种场景示意图。图1a中，终端设备102接入了网络设备101。网络设备101可以通过本申请实施例提供的预编码方法，根据终端设备反馈的预编码矩阵，对下行信道进行重构。下面结合附图详细说明。
为了降低网络设备根据终端设备反馈的预编码矩阵重构下行信道导致的量化误差，本申请提供了一种利用加权的CSI-RS进行多次CSI测量，并根据终端设备多次反馈的预编码矩阵进行下行信道重构，结合前面的描述，如图3所示，为本申请实施例提供的一种预编码方法流程示意图。参见图3，该方法包括：
步骤301：网络设备向终端设备发送第i个参考信号。
其中，第i个参考信号用于终端设备进行第i次CSI测量。第i个参考信号可以为加权后的参考信号。在一个参考信号周期内，网络设备基于参考信号配置信息向终端设备发送加权的参考信号。例如，基站使用加权矩阵F i对第i个参考信号CSI-RS进行加权，加权方式为加权矩阵与第i个参考信号CSI-RS进行乘积，并通过下行信道发送第i个参考信号CSI-RS给终端设备。相应的，终端设备基于参考信号配置信息接收参考信号。
步骤302：终端设备根据接收到的第i个加权的参考信号，确定第i个预编码矩阵。
步骤303：终端设备向网络设备反馈第i个测量信息。
其中，针对第i次测量，第i个测量信息可以包括第i个预编码矩阵对应的PMI信息，PMI信息用于指示第i个预编码矩阵的索引。第i个测量信息还可以包括第i个预编码矩阵的秩。
一种示例性说明中，终端设备中的预编码矩阵可以是终端设备预先存储在本地的，也可以是终端设备的服务基站配置给该终端设备的。网络设备中的预编码矩阵可以是网络设备预先存储在本地的，在此不做限定。
重复步骤301-302，网络设备接收终端设备发送的N个PMI信息，从而获取终端设备N次测量得到的N个预编码矩阵。
一种可能的实现方式，在每次CSI测量时，采用随机矩阵对参考信号(例如，CSI-RS)进行加权。从而，通过多次获取UE反馈的PMI对应的下行信道的特征向量后，重构下行信道。相比获取单次PMI的方式可以提高重构信道的精度。但是，上述方法中使用随机生 成的加权矩阵对参考信号加权，导致UE多次的CSI测量之间，加权矩阵互不相关，因此，多次反馈的PMI对应的预编码矩阵之间有可能存在冗余部分。另外，考虑反馈的开销，在有限次的CSI测量和反馈情况下，也无法保证获取到完整的下行信道。
基于上述问题，本申请提供另一种可能的实现方式，网络设备可以根据终端设备反馈的至少一个预编码矩阵，生成加权矩阵F N。举例来说，基于网络设备已发送N-1个参考信号，且接收到终端设备基于N-1个参考信号测量获得的N-1个预编码矩阵的场景，网络设备可以基于接收到的N-1个预编码矩阵，确定第N个参考信号对应的加权矩阵。生成加权矩阵F N的方式可以有多种，N-1个参考信号中的任一个参考信号可以表示为第i个参考信号，相应的，终端设备反馈的预编码矩阵可以表示为第i个预编码矩阵。需要说明的是N-1可以替代为其他字符，比如M，M为正整数。下面以方式a和方式b举例说明加权矩阵的实现方式。
方式a：第N个参考信号对应的加权矩阵与前N-1个参考信号对应反馈的N-1个预编码矩阵两两正交。在方式a中，还可以有多种实现方式，下面以方式a1和方式a2举例说明。
方式a1，预编码矩阵与加权矩阵F N的关系可以满足：
Figure PCTCN2020106448-appb-000008
其中，前N-1次CSI测量反馈的N个预编码矩阵中的第k个预编码矩阵可以表示为V k,k∈[1,N-1]。
Figure PCTCN2020106448-appb-000009
表示N个预编码矩阵中的第k个预编码矩阵的共轭转置矩阵。
方式a2，加权矩阵与前N-1次反馈的预编码矩阵组成的第一矩阵满足：
Figure PCTCN2020106448-appb-000010
其中，前N-1次CSI测量反馈的N-1个预编码矩阵组成的第一矩阵V c(N-1)可以有多种方式，例如，合并，并列，组合等方式。举例来说，第一矩阵V c(N-1)满足：
V c(N-1)＝[V 1,V 2,…V N-1]
下面以方式a2举例说明方式a的场景下，每次CSI测量发送的参考信号所采用的加权矩阵。
首次CSI测量时，即当N＝1时，加权矩阵可以满足：
Figure PCTCN2020106448-appb-000011
其中，
Figure PCTCN2020106448-appb-000012
为N t维的单位矩阵，即发送的第一个参考信号为未进行加权的参考信号，N t表示网络设备的发送天线数。
当发送第二个参考信号时，加权矩阵可以满足：
Figure PCTCN2020106448-appb-000013
其中，
Figure PCTCN2020106448-appb-000014
为终端设备测量第二个参考信号确定的预编码矩阵的共轭转置矩阵。
当N＞1时，根据
Figure PCTCN2020106448-appb-000015
可以确定加权矩阵可以满足：
Figure PCTCN2020106448-appb-000016
通过上述方法确定的加权矩阵为迭代的矩阵，第N个参考信号采用的加权矩阵F N为共轭对称矩阵，由于第N个参考信号对应的加权矩阵与前N-1个参考信号对应反馈的N-1个预编码矩阵两两正交，F N处于V c(N-1)构成空间的零空间内。
方式b：反馈的N-1个预编码矩阵中的至少一个预编码矩阵与加权矩阵正交。在方式b中，还可以有多种实现方式，下面以方式b1和方式b2举例说明。
方式b1，预编码矩阵与加权矩阵的关系可以满足：
Figure PCTCN2020106448-appb-000017
其中，前N-1次CSI测量反馈的N-1个预编码矩阵中的第k个预编码矩阵可以表示为V k,k∈[1,N-1]。与加权矩阵正交的预编码矩阵表示为V j，j∈[1,M]，M小于或等于N-1。
举例来说，与加权矩阵正交的预编码矩阵可以为M个。其中，M个预编码矩阵可以为从N-1个预编码矩阵中任意选择的，也可以是根据终端设备反馈的其他信息选择的，例如，根据终端设备反馈的参考信号的质量，确定M个预编码矩阵。选择的方式本申请不做限定。
方式b2，加权矩阵与前N次反馈的预编码矩阵组成的第一矩阵满足：
Figure PCTCN2020106448-appb-000018
其中，M次CSI测量反馈的M个预编码矩阵组成的第一矩阵V bM可以有多种方式，例如，合并，并列，线性组合等方式。一种可能的实现方式，第一矩阵V bM可以满足：
V bM＝[V’ 1,V’ 2,…V’ M]
其中，V’ 1,V’ 2,…V’ M可以为M个预编码矩阵中的一个或者多个预编码矩阵，M为大于等于1的整数。
在步骤302中，终端设备可以根据接收到的加权的参考信号进行信道估计，计算出第N次CSI测量的等效信道，等效信道可以满足：
Figure PCTCN2020106448-appb-000019
其中，H表示网络设备与终端设备之间的下行信道，H的维度为N r×N t，N r表示终端设备的接收天线数；N t表示网络设备的发送天线数。
从而，终端设备根据等效信道，确定等效信道
Figure PCTCN2020106448-appb-000020
的协方差矩阵R N。其中，协方差矩阵R N可以满足：
Figure PCTCN2020106448-appb-000021
对协方差矩阵R n进行特征分解，可以确定特征分解后的酉矩阵U N。其中，酉矩阵U N满足：
Figure PCTCN2020106448-appb-000022
其中，U N为特征值对应的特征向量组成的酉矩阵；Λ N为对角阵，对角线元素为协方差矩阵R N的特征值。
根据终端设备向网络设备反馈的预编码矩阵的层数v N，终端设备对Λ N中前v N个最大特征值对应的特征向量组成的矩阵U N(:,1:v N)进行量化，从而确定出相应的预编码矩阵V N。
结合上述方式a，由于第N个参考信号对应的加权矩阵与前N-1个参考信号对应反馈的N-1个预编码矩阵两两正交，因此，每次终端设备反馈的预编码矩阵V l相当于对等效信道协方差
Figure PCTCN2020106448-appb-000023
的特征向量U l(:,1:v l)的一种量化表示，此时，第一矩阵与预编码矩阵满足：
Figure PCTCN2020106448-appb-000024
其中，l∈[2,N]。
因此，可以近似认为预编码矩阵V l两两正交，从而，终端设备上报的N次预编码矩阵中对应于重构信道的特征向量可以近似认为两两正交，保证了终端设备上报的信息没有冗余，提高了资源利用率。
结合上述方式b，由于第N个参考信号对应的加权矩阵与终端设备反馈的N-1个预编码矩阵中的至少一个预编码矩阵正交，因此，以第N个参考信号对应的加权矩阵与前N-1次反馈的预编码矩阵中的M个预编码矩阵正交为例，终端设备根据接收到的加权矩阵F N，确定出的预编码矩阵V N，相当于对等效信道协方差
Figure PCTCN2020106448-appb-000025
的特征向量U N(:,1:v N)的一种量化表示，此时，第一矩阵与预编码矩阵满足：
Figure PCTCN2020106448-appb-000026
因此，可以近似认为第N次反馈的预编码矩阵V N与M个预编码矩阵正交，其中，M个预编码矩阵与第N个参考信号对应的加权矩阵正交。
举例来说，假设终端设备反馈的预编码矩阵的秩为2，第1个参考信号对应反馈的第1个预编码矩阵。第2个参考信号的加权矩阵为根据第1个预编码矩阵正交确定的，第2个参考信号对应反馈的第2个预编码矩阵，因此，第1个预编码矩阵可以近似认为与第2个预编码矩阵正交。第3个参考信号的加权矩阵可以为根据第2个预编码矩阵正交确定的，第3个参考信号对应反馈的第3个预编码矩阵，此时，第3个预编码矩阵可以近似认为与第2个预编码矩阵正交。第4个参考信号的加权矩阵可以为根据第2个预编码矩阵和第3个预编码矩阵正交确定的，第4个参考信号对应反馈的第4个预编码矩阵，此时，第4个预编码矩阵可以近似认为与第2个预编码矩阵和第3个预编码矩阵正交。在通过终端设备的4次反馈的4个预编码矩阵中，可以确定出至少6个线性独立的主特征向量(包括第1个预编码矩阵对应的2个特征向量，第2个预编码矩阵对应的2个特征向量，及第4个预编码矩阵对应的2个特征向量)。该方法提供了更加灵活的确定预编码矩阵的方式，同时，网络设备可以根据终端设备有限次反馈的预编码矩阵，降低反馈开销的同时，提高重构信道的精度。
步骤304：根据N个预编码矩阵，确定重构矩阵。
根据N个预编码矩阵确定重构矩阵的方式可以有多种，下面以方式C和方式D举例说明。
方式C，根据多个预编码矩阵进行加权平均，从而确定重构矩阵。在方式C中，还可以有多种实现方式，下面以方式C1-方式C4举例说明。需要说明的是，本申请涉及的加权矩阵的方式a和方式b中都可以适用于方式C1和方式C2。方式C3和方式C4可以适用加权矩阵为方式a的场景。
网络设备接收终端设备反馈的N个CSI测量对应的N个预编码矩阵，N个预编码矩阵中的第i个预编码矩阵可以表示为V i，i∈[1,N]。
方式C1，网络设备可以根据接收到的预编码矩阵V i与该次测量采用的加权矩阵相乘，确定加权后的预编码矩阵V” i。以加权矩阵为F i为例，加权后的预编码矩阵V” i满足：
V” i＝F iV i
针对每个加权后的预编码矩阵，可以确定中间变量W” i，一种可能的实现方式，中间变量W” i满足：
Figure PCTCN2020106448-appb-000027
从而得到重构的下行信道空间协方差矩阵Z，此时协方差矩阵Z满足：
Figure PCTCN2020106448-appb-000028
其中，a i表示第i次CSI测量计算出的中间变量的权重系数，可以通过网络设备设置，在此不做限定。一种可能的实现方式，可以进行线性归一化确定a i，例如，0＜a i＜1，且满足
Figure PCTCN2020106448-appb-000029
网络设备对协方差矩阵Z进行特征分解，从而获取特征分解后的主特征向量组成的矩阵U a：
Figure PCTCN2020106448-appb-000030
其中，Λ a表示特征分解后的特征值，U a表示特征分解后的主特征向量组成的矩阵。
Figure PCTCN2020106448-appb-000031
表示特征分解后的主特征向量组成的矩阵的共轭转置矩阵。从而，U a可直接用作发送下行信号的波束赋形的重构矩阵。
方式C2，针对接收到的N个预编码矩阵中的第i个预编码矩阵V i，可以确定中间变量W i。一种可能的实现方式，中间变量W i满足：
Figure PCTCN2020106448-appb-000032
其中，
Figure PCTCN2020106448-appb-000033
表示N个预编码矩阵中的第i个预编码矩阵的共轭转置矩阵。
从而，可以对确定的N个预编码矩阵对应的N个中间变量进行加权平均，得到重构的下行信道空间协方差矩阵Z，此时，协方差矩阵Z满足：
Figure PCTCN2020106448-appb-000034
其中，0＜λ i＜1表示第n次CSI测量计算出的中间变量的权重系数，且满足
Figure PCTCN2020106448-appb-000035
从而，网络设备对协方差矩阵Z进行特征分解，从而获取特征分解后的主特征向量组成的矩阵U b：
Figure PCTCN2020106448-appb-000036
其中，Λ b表示特征分解后的特征值，U b表示特征分解后的主特征向量组成的矩阵。
Figure PCTCN2020106448-appb-000037
表示特征分解后的主特征向量组成的矩阵的共轭转置矩阵。从而，U b可直接用作下行信号发送的波束赋形的重构矩阵。
方式C3，考虑到网络设备对多次测量得到的预编码矩阵进行加权平均时，使得各次测量结果的平均权重系数不能准确对应信道的特征信息，导致重构的下行信道精度有限。基于此，结合方式a，考虑在终端设备反馈的预编码矩阵层数为1时，终端设备对R i的最大特征值对应的特征向量U i(:,1)进行量化，即v i＝1，获取预编码矩阵V i。第i次CSI测量反馈的预编码矩阵可以作为对下行信道H的第i个特征向量
Figure PCTCN2020106448-appb-000038
的量化。
在步骤304之前，终端设备还可以向网络设备反馈信道质量信息CQI值c i，CQI值用于表示该次CSI测量的协方差矩阵对应的最大特征值的量化值。
一种可能的实现方式，还可以在步骤303中，测量信息包括CQI。或者，还可以与秩指示(rank indication，RI)上报，也可以分别上报，在此不做限定。
从而，第i次CSI测量反馈的CQI信息可代表量化的特征值
Figure PCTCN2020106448-appb-000039
则下行信道H的空间协方差满足：
Figure PCTCN2020106448-appb-000040
其中，r为下行信道的秩数，此时，r＝N。中间变量满足：
Figure PCTCN2020106448-appb-000041
从而，网络设备接收到终端设备反馈的N个预编码矩阵中的第i个预编码矩阵V i和CQI信息c i，从而确定中间变量W i以及权重系数c i，并对其进行加权平均，得到重构的下行信道空间协方差Z满足：
Figure PCTCN2020106448-appb-000042
网络设备对协方差矩阵Z进行特征分解，确定特征分解后的主特征向量即可以作为重构矩阵中的主特征向量。通过CQI信息可以对预编码矩阵进行更精准的加权平均，提升了重构的下行信道主特征向量的准确度。
方式C4，考虑到终端设备反馈的预编码矩阵层数大于1时，终端设备反馈的测量信息中并不包含估计到的下行信道主特征向量对应的特征值的信息。结合方式a，一种可能的实现方式，在步骤304之前，终端设备还可以向网络设备反馈对角阵Λ N，Λ N中的对角线元素为协方差矩阵R N的特征值，秩为v N。
从而，下行信道H的空间协方差满足：
Figure PCTCN2020106448-appb-000043
其中，r为下行信道的秩数，此时，
Figure PCTCN2020106448-appb-000044
从而，网络设备接收到终端设备反馈的N个预编码矩阵中的第i个预编码矩阵V i和对角阵Λ i，从而对其进行加权平均，得到重构的下行信道空间协方差Z满足：
Figure PCTCN2020106448-appb-000045
网络设备对协方差矩阵Z进行特征分解，确定特征分解后的主特征向量即可以作为重构矩阵中的主特征向量。通过对角阵信息可以对预编码矩阵进行更精准的加权平均，提升了重构的下行信道主特征向量的准确度。
方式D，根据多个预编码矩阵，确定重构矩阵。其中，重构矩阵中的特征向量的个数大于预编码矩阵的层数。下面以方式D1-方式D2举例说明。需要说明的是，本申请涉及上述的加权矩阵的方式a适用于方式D1，上述加权矩阵的方式b适用于方式D2。
方式D1，结合方式a，第N个参考信号对应的加权矩阵与前N-1个参考信号对应反馈的N-1个预编码矩阵两两正交的场景，网络设备确定的重构矩阵中的主特征向量的个数大于预编码矩阵的层数。
由于终端设备反馈的N个预编码矩阵近似正交，可以互补无冗余，因此，N个预编码矩阵的层数可以线性叠加，以得到的重构矩阵中的线性独立的特征向量。例如，N个预编码矩阵中第i个预编码矩阵的层数为v i，i∈[1,N]，则网络设备可以确定的线性独立的特征向量的个数可以为
Figure PCTCN2020106448-appb-000046
即重构矩阵的秩可以为
Figure PCTCN2020106448-appb-000047
从而可以有效提高重构矩阵 的精度。
在方式D1中，一种可能的实现方式，用于生成重构矩阵的第二矩阵可以满足：
V d＝[V 1,V 2,…V N]
从而，根据第二矩阵基站对矩阵V d进行施密特正交化，得到重构的下行信道的主特征向量(即重构矩阵中的特征向量)。从而，正交化后的矩阵可直接用作下行信号发送的波束赋形的重构矩阵。
方式D2，结合上述方式b，反馈的N-1个预编码矩阵中的至少一个预编码矩阵与加权矩阵正交的场景，网络设备确定的重构矩阵中的主特征向量的个数大于预编码矩阵的层数。
由于终端设备反馈的N个预编码矩阵部分近似正交，可以部分互补，因此，若N个预编码矩阵进行施密特正交化后，可以确定出K个正交化的预编码矩阵，其中，K个正交化的预编码矩阵两两正交，此时，K个正交化后的预编码矩阵的层数可以线性叠加，以得到的重构矩阵中的线性独立的特征向量。例如，K个正交化的预编码矩阵中第i个正交化后的预编码矩阵的层数为v i，i∈[1,K]，则网络设备可以确定的线性独立的特征向量的个数可以为
Figure PCTCN2020106448-appb-000048
即重构矩阵的秩可以为
Figure PCTCN2020106448-appb-000049
从而可以有效提高重构矩阵的精度。
一种可能的实现方式，用于生成重构矩阵的第二矩阵可以满足：
V” d＝[V” 1,V” 2,…V” K]
其中，V” i为K个正交化的预编码矩阵中的第i个正交化的预编码矩阵。从而，根据第二矩阵，网络设备可以根据矩阵V” d，得到重构的下行信道的主特征向量(即重构矩阵中的特征向量)。从而，正交化后的矩阵可直接用作下行信号发送的波束赋形的重构矩阵。
下面以Release15协议下，对层数限制在2层的场景下，终端设备可以向网络设备反馈的预编码矩阵的层数为2层的方式，网络设备可以根据接收到的N个预编码矩阵，确定特征向量大于2的重构矩阵。结合上述方式D1，如图4所示，具体过程如下：
步骤401：网络设备生成第1个参考信号，并向终端设备发送第1个参考信号。
其中，第1个参考信号对应的加权矩阵F 1满足：
Figure PCTCN2020106448-appb-000050
步骤402：终端设备向网络设备发送第1个预编码矩阵的指示信息。
其中，第1个预编码矩阵的指示信息可以是第1个预编码矩阵的PMI信息。
其中，终端设备根据接收到的第1个参考信号，确定第1次CSI测量的等效信道
Figure PCTCN2020106448-appb-000051
再计算协方差矩阵
Figure PCTCN2020106448-appb-000052
并对协方差矩阵R 1做特征分解得到特征向量组成的酉矩阵U 1；终端设备对U 1中前v 1列向量构成的矩阵进行量化，确定第1个预编码矩阵V 1。终端设备通过PMI反馈第1个预编码矩阵给网络设备，其中，v 1＝2；或，v 1＝1。
步骤403：网络设备根据第1个预编码矩阵，生成第2个参考信号。
其中，网络设备根据接收到的终端设备反馈的V 1，生成第2次CSI测量的加权矩阵F 2，其中
Figure PCTCN2020106448-appb-000053
通过加权矩阵F 2生成第2个参考信号。
步骤404：终端设备向网络设备发送第2个预编码矩阵的指示信息。
其中，第2个预编码矩阵的指示信息可以是第2个预编码矩阵的PMI信息。
根据接收到的第2个参考信号，确定第2次CSI测量的等效信道
Figure PCTCN2020106448-appb-000054
及协方差矩阵
Figure PCTCN2020106448-appb-000055
并对R 2做特征分解得到特征向量组成的酉矩阵U 2；终端设备对U 2中 前v 2列向量构成的矩阵进行量化，确定第2个预编码矩阵V 2。终端设备通过PMI反馈第2个预编码矩阵给网络设备，其中v 2∈[1,2]。
步骤405：网络设备接收终端设备反馈的2个预编码矩阵，确定重构矩阵。
其中，根据2个预编码矩阵V 1和V 2，生成第二矩阵。例如，第二矩阵满足：
V d＝[V 1,V 2]；
网络设备对第二矩阵V d进行施密特正交化，得到重构的下行信道v 1+v 2个主特征向量。正交化后的矩阵可直接用作下行信号发送的波束赋形的重构矩阵。
考虑到终端设备反馈的预编码矩阵互补无冗余，预编码矩阵的层数可以线性叠加，通过至少两次CSI测量和反馈的预编码矩阵，确定的重构矩阵可突破协议对层数的限制，从而有效提高重构信道的精度。举例来说，在Release15协议下，突破码本对反馈预编码矩阵层数的限制，在每次反馈的预编码矩阵层数不大于2的情况下，通过类型II码本仅用至少两次反馈就可以完整获取秩数为3或4的下行信道的主特征向量，从而实现对秩数为3或4的下行信道重构。
下面对层数限制的场景下，终端设备可以向网络设备反馈的预编码矩阵的层数小于或等于预设的限制层数，通过网络设备根据接收到的N个预编码矩阵，确定特征向量大于限制层数的重构矩阵。结合上述方式D2，如图5所示，具体过程如下：
步骤501：网络设备第i个参考信号，并向终端设备发送第i个参考信号。
步骤502：终端设备向网络设备发送第i个预编码矩阵的指示信息。
其中，第i个预编码矩阵的指示信息可以是第i个预编码矩阵的PMI信息。
重复步骤501和步骤502，网络设备可以生成N个参考信号。其中，第N个参考信号对应的加权矩阵的生成方式可以参考方式b中的生成方式，在此不再赘述。网络设备可以接收到终端设备发送的N个预编码矩阵。其中，N个预编码矩阵的层数小于或等于限制层数。例如，限制层数为3时，N个预编码矩阵的层数可以为1，或2，或3。
步骤503：网络设备根据终端设备反馈的N个预编码矩阵，确定重构矩阵。
其中，对N个预编码矩阵，进行施密特正交化，得到两两正交的K个正交化的预编码矩阵，根据K个正交化的预编码矩阵，生成第二矩阵。例如，第二矩阵满足：
V” d＝[V 1,V 2,…V K]；
网络设备对第二矩阵V” d进行施密特正交化，得到重构的下行信道
Figure PCTCN2020106448-appb-000056
个主特征向量。正交化后的矩阵可直接用作下行信号发送的波束赋形的重构矩阵。
考虑到终端设备反馈的预编码矩阵互补无冗余，预编码矩阵的层数可以线性叠加，通过至少两次CSI测量和反馈的预编码矩阵，确定的重构矩阵可突破协议对层数的限制，从而有效提高重构信道的精度。
在方式C2-方式C4及方式D1中，结合方式a，对下行信道的协方差矩阵进行特征分解后，可以表示为：
Figure PCTCN2020106448-appb-000057
其中，
Figure PCTCN2020106448-appb-000058
为特征分解后的酉矩阵，可以为下行信道H的主特征向量构成的矩阵。
Figure PCTCN2020106448-appb-000059
为对角阵，对角线元素为协方差矩阵H HH的特征值，且按从大到小的顺序排列。而终端设备反馈的N个预编码矩阵可以对应
Figure PCTCN2020106448-appb-000060
的主特征向量的量化。
下面以每次测量获得的预编码矩阵与下行信道间的关系举例说明。
第1次测量时，加权矩阵
Figure PCTCN2020106448-appb-000061
则终端设备反馈的第1个预编码矩阵V 1是下行信道H的v 1个主特征向量构成的矩阵
Figure PCTCN2020106448-appb-000062
第2次CSI测量时，加权矩阵F 2满足：
Figure PCTCN2020106448-appb-000063
终端设备根据接收到的第2个参考信号，确定的等效信道
Figure PCTCN2020106448-appb-000064
的协方差矩阵R 2可以满足：
Figure PCTCN2020106448-appb-000065
其中，
Figure PCTCN2020106448-appb-000066
表示下行信道除去第1个预编码矩阵确定的前v 1个主特征向量后，剩余的特征向量构成的矩阵。可见，第2个预编码矩阵V 2是对下行信道第v 1+1到第v 1+v 2个特征向量的量化表达。
依次迭代可得，第i次CSI测量时，终端设备根据接收到的第i个参考信号，确定的等效信道的协方差矩阵R i满足：
Figure PCTCN2020106448-appb-000067
其中，
Figure PCTCN2020106448-appb-000068
表示下行信道H除去前γ个主特征向量后，剩余特征向量构成的矩阵，且
Figure PCTCN2020106448-appb-000069
此时，V i是
Figure PCTCN2020106448-appb-000070
中前v i个特征向量的一种量化表达，即第i次CSI测量时，终端设备反馈的预编码矩阵，可以对应下行信道空间协方差中去掉前γ个主特征向量后的v i个特征向量。
所以，每次终端设备反馈的预编码矩阵对于重构下行信道采用的重构矩阵是互补的，且无冗余，对于秩数为r的下行信道，只需终端设备不多于r次的CSI测量，即可完整获取下行信道的前r个主特征向量。
从而，实现在有限次的测量下，获取完整的信道空间协方差矩阵，从而减少量化误差，提升波束赋形的准确性。
在方式C2至方式C3及方式D1中，结合方式b，对下行信道的协方差矩阵进行特征分解后，可以表示为：
Figure PCTCN2020106448-appb-000071
其中，
Figure PCTCN2020106448-appb-000072
为特征分解后的酉矩阵，可以为下行信道H的主特征向量构成的矩阵。
Figure PCTCN2020106448-appb-000073
为对角阵，对角线元素为协方差矩阵H HH的特征值。而终端设备反馈的N个预编码矩阵可以对应
Figure PCTCN2020106448-appb-000074
的主特征向量的量化。
下面以每次测量获得的预编码矩阵与下行信道间的关系举例说明。
第1次测量时，加权矩阵
Figure PCTCN2020106448-appb-000075
则终端设备反馈的第1个预编码矩阵V 1是下行信道H的前v 1个主特征向量构成的矩阵
Figure PCTCN2020106448-appb-000076
以重构矩阵满足：
[a1,a2,a3,…,ar]
其中，ai为重构矩阵中的主特征向量，ai的长度为N t，i∈[1,r]。其中，N t表示网络设备的发送天线数。r为重构矩阵的秩。
以v 1为1为例，
Figure PCTCN2020106448-appb-000077
满足：
Figure PCTCN2020106448-appb-000078
其中，第1个预编码矩阵V 1＝b1，b1对应第1个主特征向量a1。b1的长度为N t。其中，N t表示网络设备的发送天线数。
第2次CSI测量时，加权矩阵F 2满足：
Figure PCTCN2020106448-appb-000079
终端设备根据接收到的第2个参考信号，确定的等效信道
Figure PCTCN2020106448-appb-000080
的协方差矩阵R 2可以满足：
Figure PCTCN2020106448-appb-000081
其中，结合上述例子，b1·F 2＝0，第二矩阵V b1＝[b1]。
Figure PCTCN2020106448-appb-000082
表示下行信道除去第1个预编码矩阵确定的前v 1个主特征向量后，剩余的特征向量构成的矩阵。以v 2为2为例，
Figure PCTCN2020106448-appb-000083
满足：
Figure PCTCN2020106448-appb-000084
其中，b2可以对应重构矩阵中的主特征向量a2；b3可以对应重构矩阵中的主特征向量a3。其中，b2和b3的长度分别为N t。其中，N t表示网络设备的发送天线数。可见，第2个预编码矩阵V 2是对下行信道第v 1+1到第v 1+v 2个特征向量的量化表达。
第3次CSI测量时，加权矩阵F 3满足：
Figure PCTCN2020106448-appb-000085
一种可能的实现方式，第二矩阵V b2＝[V 1]。结合上述例子，b1·F 3＝0。
此时，终端设备根据接收到的第3个参考信号，确定的等效信道
Figure PCTCN2020106448-appb-000086
的协方差矩阵R 3可以满足：
Figure PCTCN2020106448-appb-000087
其中，
Figure PCTCN2020106448-appb-000088
表示下行信道除去第1个预编码矩阵确定的前v 1个主特征向量后，剩余的特征向量构成的矩阵。以v 3为3为例，
Figure PCTCN2020106448-appb-000089
满足：
Figure PCTCN2020106448-appb-000090
其中，b4,b5,b6的每个特征向量的长度为N t。第3个预编码矩阵V 3和第1个预编码矩阵的特征向量a1相互正交，因此，b4,b5,b6可以对应重构矩阵中除主特征向量a1的其他3个主特征向量，但是，由于V 3与b2和b3不正交，因此，第三预编码矩阵V 3和特征向量b2和特征向量b3之间可能存在冗余。此时，第3个预编码矩阵V 3是对下行信道第v 1+1到第v 1+v 3个特征向量的量化表达。
另一种可能的实现方式，第二矩阵V b2＝[V 2]。结合上述例子，[b2,b3]·F 3＝0。由此生成第3个参考信号。此时，终端设备根据接收到的第3个参考信号，确定的等效信道
Figure PCTCN2020106448-appb-000091
的协方差矩阵R 3可以满足：
Figure PCTCN2020106448-appb-000092
其中，
Figure PCTCN2020106448-appb-000093
表示下行信道除去第2个预编码矩阵确定的第v 1+1到第v 1+v 2个特征向量后，剩余的特征向量构成的矩阵。以v 3为3为例，选取
Figure PCTCN2020106448-appb-000094
中特征值最大的3个特征向量构成第3个预编码矩阵V’ 3，第3个预编码矩阵V’ 3满足：
V’ 3＝[b4’，b5’，b6’]
其中，b4’，b5’，b6’的每个特征向量的长度为N t。V 3和b2，b3相互正交，因此，b4’，b5’，b6’可以对应重构矩阵中除主特征向量a2、a3的其他3个主特征向量，但是，由于V 3和第1个预编码矩阵的特征向量b1不正交，因此，第3个预编码矩阵V 3和主特征向量b1之间可能存在冗余。此时，第3个预编码矩阵V 3可以是对下行信道除第v 1+1到第v 1+v 2个特征向量之外的其他v 3个特征向量的量化表达。
依次迭代可得，第i次CSI测量时，终端设备根据接收到的第i个参考信号，确定的等效信道的协方差矩阵R i满足：
Figure PCTCN2020106448-appb-000095
其中，
Figure PCTCN2020106448-appb-000096
表示下行信道H除去γ个主特征向量后，剩余特征向量构成的矩阵，且
Figure PCTCN2020106448-appb-000097
其中，K1个正交化的预编码矩阵中第p个正交化后的预编码矩阵的层数为v p，p∈[1,K1]。v p表示网络设备接收到的i个预编码矩阵经过正交化后，确定出的M个正交化的预编码矩阵中的每个正交化的预编码矩阵的层数。若i个预编码矩阵进行施密特正交化后，可以确定出K1个正交化的预编码矩阵，其中，K1个正交化的预编码矩阵两两正交，此时，K1个正交化后的预编码矩阵的层数可以线性叠加，以得到的重构矩阵中的线性独立的特征向量。
结合上述例子，根据前3个预编码矩阵V 1，V 2，V 3，确定出的正交化的预编码矩阵可以为：V 1，V 2，V” 3。此时，可以确定出V 1对应1个特征向量，V 2对应2个特征向量，V” 3为与V 1和V 2都正交的特征向量，即从[b4,b5,b6]确定出的与b1、b2和b3都相互正交的特征向量，至少包括1个特征向量，最多3个特征向量。因此，γ至少为4，最多为6。
再比如，第i个参考信号对应的加权矩阵与前i-1个预编码矩阵中的M i个预编码矩阵正交，其中，该M i个预编码矩阵中，若第1个预编码矩阵、第3个预编码矩阵和第5个预编码矩阵两两正交，此时，第1个预编码矩阵对应v 1个特征向量，第3个预编码矩阵对应v 3个特征向量，第5个预编码矩阵对应v 5个特征向量，γ＝v 1+v 3+v 5。
此时，V i是
Figure PCTCN2020106448-appb-000098
中v i个特征向量的一种量化表达，即第i次CSI测量时，终端设备反馈的预编码矩阵，可以对应下行信道空间协方差中去掉与加权矩阵正交的预编码矩阵对应的γ个主特征向量后的v i个特征向量。
所以，每次终端设备反馈的预编码矩阵对于重构下行信道采用的重构矩阵可以部分互补的，对于秩数为r的下行信道，只需终端设备有限次的CSI测量，即可完整获取下行信道的前r个主特征向量。从而，实现在有限次的测量下，获取完整的信道空间协方差矩阵，从而减少量化误差，提升波束赋形的准确性。
基于与上述预编码方法相同的构思，下面结合附图介绍本申请实施例中用来实现上述方法的装置。因此，上文中的内容均可以用于后续实施例中，重复的内容不再赘述。图6为本申请实施例提供的通信装置600的示意性框图。
通信装置600包括处理模块601和收发模块602。示例性地，通信装置600可以是网络设备，也可以是应用于网络设备中的芯片或者其他具有上述网络设备功能的组合器件、部件等。当通信装置600是网络设备时，收发模块602可以是收发器，收发器可以包括天线和射频电路等，处理模块601可以是处理器，例如基带处理器，基带处理器中可以包括一个或多个中央处理单元(central processing unit，CPU)。当通信装置600是芯片系统时，收发模块602可以是芯片(例如基带芯片)的输入输出接口、处理模块601可以是芯片系统的处理器，可以包括一个或多个中央处理单元。应理解，本申请实施例中的处理模块601可以由处理器或处理器相关电路组件实现，收发模块602可以由收发器或收发器相关电路组件实现。
例如，处理模块601可以用于执行图2或图3所示的实施例中由网络设备所执行的除了收发操作之外的全部操作，和/或用于支持本文所描述的技术的其它过程。收发模块602可以用于执行图2或图3所示的实施例中由网络设备所执行的全部收发操作，和/或用于支持本文所描述的技术的其它过程。
另外，收发模块602可以是一个功能模块，该功能模块既能完成发送操作也能完成接收操作，例如收发模块602可以用于执行图2或图3所示的实施例中由网络设备所执行的全部发送操作和接收操作，例如，在执行发送操作时，可以认为收发模块602是发送模块，而在执行接收操作时，可以认为收发模块602是接收模块；或者，收发模块602也可以是两个功能模块，收发模块602可以视为这两个功能模块的统称，这两个功能模块分别为发送模块和接收模块，发送模块用于完成发送操作，例如发送模块可以用于执行图2或图3所示的实施例的任一个实施例中由网络设备所执行的全部发送操作，接收模块用于完成接收操作，例如接收模块可以用于执行图2或图3所示的实施例由网络设备所执行的全部接收操作。
其中，处理模块601，用于根据N个预编码矩阵确定重构矩阵，所述N个预编码矩阵包括所述N-1个预编码矩阵和所述第N个预编码矩阵；根据所述重构矩阵发送下行信号；所述N-1为正整数。
收发模块602，用于向终端设备发送N-1个参考信号；所述网络设备从所述终端设备接收所述N-1个参考信号对应的N-1个预编码矩阵的指示信息；向所述终端设备发送第N个参考信号，所述第N个参考信号是通过加权矩阵加权得到的，所述加权矩阵与所述N-1个预编码矩阵的至少一个预编码矩阵正交；从所述终端设备接收所述第N个参考信号对应的第N个预编码矩阵的指示信息。
一种可能的实现方式，所述第N个参考信号的加权矩阵F N满足：
Figure PCTCN2020106448-appb-000099
其中，V c(N-1)表示所述N-1个预编码矩阵组成的第一矩阵；
Figure PCTCN2020106448-appb-000100
表示所述第一矩阵的共轭转置矩阵。
一种可能的实现方式，所述第一矩阵满足：
V c(N-1)＝[V 1,V 2,…V N-1]
其中，V k表示所述N-1个预编码矩阵中的第k个预编码矩阵；所述k∈[1,N-1]；所述k为正整数。
一种可能的实现方式，所述N个预编码矩阵中的第i个预编码矩阵的层数为v i；所述N个预编码矩阵中的第i个预编码矩阵对应所述重构矩阵中的v i个特征向量；所述i∈[1,N]；所述i为正整数；所述v i为正整数。
一种可能的实现方式，处理模块601，具体用于根据加权后的所述N个预编码矩阵，确定所述重构矩阵。
一种可能的实现方式，所述重构矩阵为根据第一协方差矩阵Z1确定的；所述第一协方差矩阵Z1满足：
Figure PCTCN2020106448-appb-000101
其中，0＜λ i＜1，λ i表示N个预编码矩阵中的第i个预编码矩阵对应在所述第一协方差矩阵中的权重系数；
Figure PCTCN2020106448-appb-000102
所述V i表示所述N个预编码矩阵中的第i个预编码矩阵； 所述
Figure PCTCN2020106448-appb-000103
表示所述N个预编码矩阵中的第i个预编码矩阵的共轭转置矩阵；所述i∈[1,N]；所述i为正整数。
一种可能的实现方式，所述处理模块601，具体用于根据N个预编码矩阵组成的第二矩阵，确定所述重构矩阵；所述第二矩阵满足：
V c＝[V 1,V 2,…V N]
其中，V i表示所述N个预编码矩阵中的第i个预编码矩阵；所述i∈[1,N]；所述i为正整数。
一种可能的实现方式，所述N个预编码矩阵中的第i个预编码矩阵的层数为1；
所述收发模块602，还用于接收来自所述终端设备的CQI值；该CQI值对应所述第i个第i个预编码矩阵；所述i∈[1,N]；所述i为正整数。
一种可能的实现方式，所述重构矩阵为根据第二协方差矩阵Z2确定的；所述第二协方差矩阵Z2满足：
Figure PCTCN2020106448-appb-000104
其中，C i表示所述第i个参考信号对应的CQI值；所述V i表示所述N个预编码矩阵中的第i个预编码矩阵；所述
Figure PCTCN2020106448-appb-000105
表示所述N个预编码矩阵中的第i个预编码矩阵的共轭转置矩阵；所述i∈[1,N]；所述i为正整数。
基于与上述预编码方法相同的构思，如图7所示，本申请实施例还提供一种通信装置700。通信装置700可用于实现上述方法实施例中由网络设备所执行的方法，可以参见上述方法实施例中的说明，其中通信装置700可以为网络设备，或者可以位于网络设备中，可以为发端设备。
通信装置700包括一个或多个处理器701。处理器701可以是通用处理器或者专用处理器等。例如可以是基带处理器、或中央处理器。基带处理器可以用于对通信协议以及通信数据进行处理，中央处理器可以用于对通信装置(如，网络设备或芯片等)进行控制，执行软件程序，处理软件程序的数据。通信装置700可以包括收发单元，用以实现信号的输入(接收)和输出(发送)。例如，收发单元可以为收发器，射频芯片等。
通信装置700包括一个或多个处理器701，一个或多个处理器701可实现上述所示的实施例中网络设备执行的方法。
可选的，处理器701除了可以实现上述所示的实施例中的方法，还可以实现其他功能。可选的，一种实现方式中，处理器701可以执行计算机程序，使得通信装置700执行上述方法实施例中网络设备所执行的方法。该计算机程序可以全部或部分存储在处理器701内，如计算机程序703，也可以全部或部分存储在与处理器701耦合的存储器702中，如计算机程序704，也可以通过计算机程序703和704共同使得通信装置700执行上述方法实施例中网络设备所执行的方法。
在又一种可能的实现方式中，通信装置700也可以包括电路，该电路可以实现前述方法实施例中网络设备所执行的功能。
在又一种可能的实现方式中，通信装置700中可以包括一个或多个存储器702，其上 存储有计算机程序704，该计算机程序可在处理器上被运行，使得通信装置700执行上述方法实施例中描述的编码方法。可选的，存储器中还可以存储有数据。可选的，处理器中也可以存储计算机程序和/或数据。例如，上述一个或多个存储器702可以存储上述实施例中所描述的关联或对应关系，或者上述实施例中所涉及的相关的参数或表格等。其中，处理器和存储器可以单独设置，也可以集成或耦合在一起。
在又一种可能的实现方式中，通信装置700还可以包括收发单元705。处理器701可以称为处理单元，对通信装置(网络设备)进行控制。收发单元705可以称为收发机、收发电路、或者收发器等，用于实现数据或控制信令的收发。
例如，如果通信装置700为应用于通信设备中的芯片或者其他具有上述通信设备功能的组合器件、部件等，通信装置700中可以包括收发单元705。
在又一种可能的实现方式中，通信装置700还可以包括收发单元705以及天线706。处理器701可以称为处理单元，对通信装置(网络设备)进行控制。收发单元705可以称为收发机、收发电路、或者收发器等，用于通过天线706实现装置的收发功能。
在一种实施例中，收发单元705，用于向终端设备发送N-1个参考信号；所述网络设备从所述终端设备接收所述N-1个参考信号对应的N-1个预编码矩阵的指示信息；向所述终端设备发送第N个参考信号，所述第N个参考信号是通过加权矩阵加权得到的，所述加权矩阵与所述N-1个预编码矩阵的至少一个预编码矩阵正交；从所述终端设备接收所述第N个参考信号对应的第N个预编码矩阵的指示信息；
处理器701，用于根据N个预编码矩阵确定重构矩阵，所述N个预编码矩阵包括所述N-1个预编码矩阵和所述第N个预编码矩阵；根据所述重构矩阵发送下行信号；所述N-1为正整数。
应注意，本申请实施例中的处理器可以是一种集成电路芯片，具有信号的处理能力。在实现过程中，上述方法实施例的各步骤可以通过处理器中的硬件的集成逻辑电路或者软件形式的计算机程序完成。上述的处理器可以是通用处理器、数字信号处理器(digital signal processor，DSP)、专用集成电路(application specific integrated circuit，ASIC)、现成可编程门阵列(field programmable gate array，FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件。可以实现或者执行本申请实施例中公开的各方法、步骤及逻辑框图。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。结合本申请实施例公开的方法步骤可以直接体现为硬件译码处理器执行完成，或者用译码处理器中的硬件及软件模块组合执行完成。软件模块可以位于随机存储器，闪存、只读存储器，可编程只读存储器或者电可擦写可编程存储器、寄存器等本领域成熟的存储介质中。该存储介质位于存储器，处理器读取存储器中的信息，结合其硬件完成上述方法的步骤。
可以理解，本申请实施例中的存储器可以是易失性存储器或非易失性存储器，或可包括易失性和非易失性存储器两者。其中，非易失性存储器可以是只读存储器(read-only memory，ROM)、可编程只读存储器(programmable ROM，PROM)、可擦除可编程只读存储器(erasable PROM，EPROM)、电可擦除可编程只读存储器(electrically EPROM，EEPROM)或闪存。易失性存储器可以是随机存取存储器(random access memory，RAM)，其用作外部高速缓存。通过示例性但不是限制性说明，许多形式的RAM可用，例如静态随机存取存储器(static RAM，SRAM)、动态随机存取存储器(dynamic RAM，DRAM)、同步动态随机存取存储器(synchronous DRAM，SDRAM)、双倍数据速率同步动态随机存 取存储器(double data rate SDRAM，DDR SDRAM)、增强型同步动态随机存取存储器(enhanced SDRAM，ESDRAM)、同步连接动态随机存取存储器(synchlink DRAM，SLDRAM)和直接内存总线随机存取存储器(direct rambus RAM，DR RAM)。应注意，本文描述的系统和方法的存储器旨在包括但不限于这些和任意其它适合类型的存储器。
本申请实施例还提供一种计算机可读存储介质，其上存储有计算机程序，该计算机程序被计算机执行时实现上述应用于网络设备的任一方法实施例的方法。
本申请实施例还提供一种计算机程序产品，该计算机程序产品被计算机执行时实现上述应用于网络设备的任一方法实施例的方法。
应注意，本文描述的存储器旨在包括但不限于这些和任意其它适合类型的存储器。
应理解，在本申请的各种实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对一个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。
功能如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本申请各个实施例方法的全部或部分步骤。而前述的计算机可读存储介质，可以是计算机能够存取的任何可用介质。以此为例但不限于：计算机可读介质可以包括随机存取存储器(random access memory，RAM)、只读存储器(read-only memory，ROM)、电可擦可编程只读存储器(electrically erasable programmable read only memory，EEPROM)、紧凑型光盘只读存储器(compact disc read-only memory，CD-ROM)、通用串行总线闪存盘(universal serial bus flash disk)、移动硬盘、或其他光盘存储、磁盘存 储介质或者其他磁存储设备、或者能够用于携带或存储具有指令或数据结构形式的期望的程序代码并能够由计算机存取的任何其他介质。
以上，仅为本申请的具体实施方式，但本申请实施例的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请实施例揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请实施例的保护范围之内。因此，本申请实施例的保护范围应以权利要求的保护范围为准。

Claims (22)

  1. 一种预编码方法，其特征在于，包括：
    网络设备向终端设备发送N-1个参考信号；
    所述网络设备从所述终端设备接收所述N-1个参考信号对应的N-1个预编码矩阵的指示信息；
    所述网络设备向所述终端设备发送第N个参考信号，所述第N个参考信号是通过加权矩阵加权得到的，所述加权矩阵与所述N-1个预编码矩阵中的至少一个预编码矩阵正交；
    所述网络设备从所述终端设备接收所述第N个参考信号对应的第N个预编码矩阵的指示信息；
    所述网络设备根据N个预编码矩阵确定重构矩阵，所述N个预编码矩阵包括所述N-1个预编码矩阵和所述第N个预编码矩阵；
    所述网络设备根据所述重构矩阵发送下行信号；所述N-1为正整数。
  2. 根据权利要求1所述的方法，其特征在于，所述第N个参考信号的加权矩阵F N满足：
    Figure PCTCN2020106448-appb-100001
    其中，V c(N-1)表示所述N-1个预编码矩阵组成的第一矩阵；
    Figure PCTCN2020106448-appb-100002
    表示所述第一矩阵的共轭转置矩阵。
  3. 根据权利要求2所述的方法，其特征在于，所述第一矩阵满足：
    V c(N-1)＝[V 1,V 2,…V N-1]
    其中，V k表示所述N-1个预编码矩阵中的第k个预编码矩阵；所述k∈[1,N-1]；所述k为正整数。
  4. 根据权利要求1-3任一项所述的方法，其特征在于，所述N个预编码矩阵中的第i个预编码矩阵的层数为v i；所述第i个预编码矩阵对应所述重构矩阵中的v i个特征向量；所述i∈[1,N]；所述i为正整数；所述v i为正整数。
  5. 根据权利要求1-4任一项所述的方法，其特征在于，所述网络设备根据所述N个预编码矩阵确定重构矩阵，包括：
    所述网络设备根据加权后的所述N个预编码矩阵，确定所述重构矩阵。
  6. 根据权利要求5所述的方法，其特征在于，所述重构矩阵为根据第一协方差矩阵Z1确定的；所述第一协方差矩阵Z1满足：
    Figure PCTCN2020106448-appb-100003
    其中，0<λ i<1，λ i表示N个预编码矩阵中的第i个预编码矩阵对应在所述第一协方差矩阵中的权重系数；
    Figure PCTCN2020106448-appb-100004
    所述V i表示所述N个预编码矩阵中的第i个预编码矩阵；所述
    Figure PCTCN2020106448-appb-100005
    表示所述N个预编码矩阵中的第i个预编码矩阵的共轭转置矩阵；所述i∈[1,N]；所述i为正整数。
  7. 根据权利要求1-4任一项所述的方法，其特征在于，所述网络设备根据N个预编码矩阵确定重构矩阵，包括：
    所述网络设备根据所述N个预编码矩阵组成的第二矩阵，确定所述重构矩阵；所述第 二矩阵满足：
    V c＝[V 1,V 2,…V N]
    其中，V i表示所述N个预编码矩阵中的第i个预编码矩阵；所述i∈[1,N]；所述i为正整数。
  8. 根据权利要求1-5任一项所述的方法，其特征在于，所述N个预编码矩阵中的第i个预编码矩阵的层数为1；所述方法还包括：
    所述网络设备从所述终端设备接收与所述第i个参考信号对应的信道质量信息CQI值；所述i∈[1,N]；所述i为正整数。
  9. 根据权利要求8所述的方法，其特征在于，所述重构矩阵为根据第二协方差矩阵Z2确定的；所述第二协方差矩阵Z2满足：
    Figure PCTCN2020106448-appb-100006
    其中，C i表示所述第i个参考信号对应的CQI值；所述V i表示所述第i个预编码矩阵；所述
    Figure PCTCN2020106448-appb-100007
    表示所述第i个预编码矩阵的共轭转置矩阵；所述i∈[1,N]；所述i为正整数。
  10. 一种通信装置，其特征在于，包括：
    收发模块，用于向终端设备发送N-1个参考信号；所述网络设备从所述终端设备接收所述N-1个参考信号对应的N-1个预编码矩阵的指示信息；向所述终端设备发送第N个参考信号，所述第N个参考信号是通过加权矩阵加权得到的，所述加权矩阵与所述N-1个预编码矩阵的至少一个预编码矩阵正交；从所述终端设备接收所述第N个参考信号对应的第N个预编码矩阵的指示信息；
    处理模块，用于根据N个预编码矩阵确定重构矩阵，所述N个预编码矩阵包括所述N-1个预编码矩阵和所述第N个预编码矩阵；根据所述重构矩阵发送下行信号；所述N-1为正整数。
  11. 根据权利要求10所述的装置，其特征在于，所述第N个参考信号的加权矩阵F N满足：
    Figure PCTCN2020106448-appb-100008
    其中，V c(N-1)表示所述N-1个预编码矩阵组成的第一矩阵；
    Figure PCTCN2020106448-appb-100009
    表示所述第一矩阵的共轭转置矩阵。
  12. 根据权利要求11所述的装置，其特征在于，所述第一矩阵满足：
    V c(N-1)＝[V 1,V 2,…V N-1]
    其中，V k表示所述N-1个预编码矩阵中的第k个预编码矩阵；所述k∈[1,N-1]；所述k为正整数。
  13. 根据权利要求10-12任一项所述的装置，其特征在于，所述N个预编码矩阵中的第i个预编码矩阵的层数为v i；所述第i个预编码矩阵对应所述重构矩阵中的v i个特征向量；所述i∈[1,N]；所述i为正整数；所述v i为正整数。
  14. 根据权利要求10-13任一项所述的装置，其特征在于，所述处理模块，具体用于根据加权后的所述N个预编码矩阵，确定所述重构矩阵。
  15. 根据权利要求14所述的装置，其特征在于，所述重构矩阵为根据第一协方差矩 阵Z1确定的；所述第一协方差矩阵Z1满足：
    Figure PCTCN2020106448-appb-100010
    其中，0<λ i<1，λ i表示第i个预编码矩阵对应在所述第一协方差矩阵中的权重系数；
    Figure PCTCN2020106448-appb-100011
    所述V i表示所述第i个预编码矩阵；所述
    Figure PCTCN2020106448-appb-100012
    表示所述第i个预编码矩阵的共轭转置矩阵；所述i∈[1,N]；所述i为正整数。
  16. 根据权利要求10-15任一项所述的装置，其特征在于，所述处理模块，具体用于根据N个预编码矩阵组成的第二矩阵，确定所述重构矩阵；所述第二矩阵满足：
    V c＝[V 1,V 2,…V N]
    其中，V i表示所述N个预编码矩阵中的第i个预编码矩阵；所述i∈[1,N]；所述i为正整数。
  17. 根据权利要求10-14任一项所述的装置，其特征在于，所述第i个预编码矩阵的层数为1；
    所述收发模块，还用于从所述终端设备接收与所述第i个参考信号对应的信道质量信息CQI值；所述i∈[1,N]；所述i为正整数。
  18. 根据权利要求17所述的装置，其特征在于，所述重构矩阵为根据第二协方差矩阵Z2确定的；所述第二协方差矩阵Z2满足：
    Figure PCTCN2020106448-appb-100013
    其中，C i表示所述第i个参考信号对应的CQI值；所述V i表示所述第i个预编码矩阵；所述
    Figure PCTCN2020106448-appb-100014
    表示所述N个预编码矩阵中的第i个预编码矩阵的共轭转置矩阵；所述i∈[1,N]；所述i为正整数。
  19. 一种通信装置，其特征在于，所述装置包括处理器和通信接口；
    所述通信接口，用于接收代码指令并传输至所述处理器；所述处理器运行所述代码指令以执行如权利要求1至9任一项所述的方法。
  20. 一种芯片，其特征在于，所述芯片包括至少一个处理器和收发器，所述收发器和所述至少一个处理器通过线路互联，所述处理器通过运行指令，以执行权利要求1到9任一项所述的方法。
  21. 一种可读存储介质，其特征在于，所述可读存储介质存储指令，当所述指令被执行时，使如权利要求1-9中任一项所述的方法被实现。
  22. 一种计算机程序产品，其特征在于，所述计算机程序产品包括：计算机程序代码，当计算机程序代码在计算机上运行时，使得计算机执行如权利要求1-9中任一项所述的方法。
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114614866A (zh) * 2022-03-25 2022-06-10 展讯半导体(南京)有限公司 共轭对称矩阵数据的存取方法及装置、终端
WO2024001655A1 (zh) * 2022-06-29 2024-01-04 华为技术有限公司 一种通信方法及装置
WO2024045666A1 (zh) * 2022-08-31 2024-03-07 中兴通讯股份有限公司 信道重构方法，通信节点及存储介质

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106487435A (zh) * 2015-08-24 2017-03-08 电信科学技术研究院 一种传输编码指示信息和确定预编码矩阵的方法和装置
WO2018221431A1 (ja) * 2017-06-02 2018-12-06 日本電気株式会社 無線装置及び無線通信方法
CN111342873A (zh) * 2018-12-18 2020-06-26 华为技术有限公司 一种信道测量方法和通信装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106487435A (zh) * 2015-08-24 2017-03-08 电信科学技术研究院 一种传输编码指示信息和确定预编码矩阵的方法和装置
WO2018221431A1 (ja) * 2017-06-02 2018-12-06 日本電気株式会社 無線装置及び無線通信方法
CN111342873A (zh) * 2018-12-18 2020-06-26 华为技术有限公司 一种信道测量方法和通信装置

Cited By (3)

* Cited by examiner, † Cited by third party
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CN114614866A (zh) * 2022-03-25 2022-06-10 展讯半导体(南京)有限公司 共轭对称矩阵数据的存取方法及装置、终端
WO2024001655A1 (zh) * 2022-06-29 2024-01-04 华为技术有限公司 一种通信方法及装置
WO2024045666A1 (zh) * 2022-08-31 2024-03-07 中兴通讯股份有限公司 信道重构方法，通信节点及存储介质

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