Pre-coding method and communication apparatus

Abstract

The present application relates to the field of communications, and specifically relates to a pre-coding method and a communication apparatus. For service scenarios such as XR and intelligent robots, the coverage capability of an NR cannot support a low-latency and high-reliability service having a large data amount. Provided in the present application is an independent sub-band precoding method. Data of each sub-band is sent via some antenna ports of a sending end, which can reduce PAPR power back-off, i.e., increasing transmission power of a terminal or a base station, thereby enhancing a coverage capability.

Description

Precoding method and communication apparatus TECHNICAL FIELD

[0001] The present application relates to the technical field of communication, and in particular to a precoding method and a communication apparatus. BACKGROUND

[0002] In recent years, with the continuous development of the fifth generation (5th generation, 5G) communication system, the data transmission delay is continuously reduced, and the transmission capacity is getting larger and larger, and the 5G communication system gradually penetrates into some real-time strong, large data capacity required multimedia services, such as video transmission, cloud gaming (CG) and extended reality (XR), intelligent robots, etc., wherein XR includes virtual reality (VR) and augmented reality (AR).

[0003] For XR, intelligent robot and other service scenarios, the uplink coverage capability of NR (new radio) cannot support the above-mentioned large data volume, low delay and high reliability service. The main reason for limited coverage is that the uplink transmit power of UE (user equipment) is limited, resulting in low SNR (signal-to-noise ratio). Secondly, the PAPR (peak to average power ratio) of OFDM (orthogonal frequency division multiplexing) waveform is high, and the UE uplink power needs to be backed off to work in the linear working zone, resulting in further reduction of the transmit power.

[0004] In existing wireless communication systems, such as LTE (long term evolution) systems and NR systems, MIMO (multiple input multiple output) transmission of uplink signals supports wideband precoding. Considering the frequency selectivity of the channel, multiple subbands share one precoding matrix, which will reduce the precoding performance. In order to improve the coverage capability, each subband can use its own precoding matrix, i.e. subband precoding, to improve the precoding performance. However, subband precoding will increase the PAPR of the OFDM waveform, resulting in further reduction of the UE transmit power, and the uplink coverage will be further deteriorated.

[0005] Therefore, how to improve the coverage capability of the terminal or the base station is a technical problem to be solved. SUMMARY

[0006] The embodiment of the present application provides a precoding method and a communication device, which are used for improving the coverage capability of a terminal device and a network device, improving transmission efficiency, and supporting a large data volume, low latency and high reliability service.

[0007] In a first aspect, the embodiment of the present application provides a precoding method, which can be executed by a terminal device, a component of the terminal device, such as a processor, a chip or a chip system of the terminal device, or a logic module or software capable of realizing all or part of the terminal device functions.

[0008] The method provided in the first aspect comprises the following steps: receiving first information from a network device, the first information being used for indicating a number M of subbands, a number K of precoding matrices, and a number N of antenna ports corresponding to each subband, wherein M and K are integers greater than 1, K is less than or equal to M, and N is an integer greater than or equal to 1. When data is transmitted to the network device, N is less than a number L of antenna ports of the terminal device, and L is an integer greater than 1. When data is received from the network device, N is less than a number P of antenna ports of the network device, and P is an integer greater than 1.

[0009] In a possible implementation, the first information is used for indicating that a precoding type adopted by the terminal device for uplink transmission is independent subband precoding, or the first information is used for indicating that a precoding type adopted by the network device for downlink transmission is independent subband precoding, wherein the precoding type comprises full-band precoding, subband precoding and independent subband precoding.

[0010] In the embodiment of the present application, after the terminal device receives the first information, it can be determined that the independent subband precoding is adopted for uplink transmission, or it can be determined that the network device adopts the independent subband precoding for downlink transmission.

[0011] The method provided in the first aspect further comprises the following steps: receiving second information from the network device, the second information being used for indicating a corresponding relationship between the M subbands and the K precoding matrices, and a corresponding relationship between each subband and the N antenna ports.

[0012] In a possible implementation, configuration information of the subband is further received, the configuration information of the subband being used for indicating a bandwidth of the subband, and / or a number of the subbands, and / or a starting position of the subband.

[0013] In a possible implementation, third information from the network device is further received, the third information being used for indicating the K precoding matrices. Based on the second information and the third information, data is transmitted to the network device.

[0014] In the embodiments of the present application, the terminal device sends uplink data to the network device by using independent sub-band precoding, which can reduce the power backoff of PAPR, is equivalent to improving the transmission power of the terminal device, and can enhance the uplink coverage capability.

[0015] In a possible implementation, the data from the network device is received based on the second message.

[0016] The method provided in the first aspect further includes: sending fourth information to the network device, the fourth information being used to indicate the number M of sub-bands, the number K of precoding matrices, and the number N of antenna ports corresponding to each sub-band, wherein M and K are integers greater than 1, K is less than or equal to M, N is an integer greater than or equal to 1, N is less than the number L of antenna ports of the terminal device or N is less than the number P of antenna ports of the network device, and L and P are integers greater than 1.

[0017] In a possible implementation, fifth information from the network device is received, the fifth information being used to indicate whether the network device expects to obtain the precoding type supported by the terminal device. When the fifth information indicates that the network device expects to obtain the precoding type supported by the terminal device, the terminal device sends fourth information to the network device, the fourth information being used to indicate the precoding type supported by the terminal device, wherein the precoding type supported by the terminal device includes full-band precoding, and / or sub-band precoding, and / or independent sub-band precoding.

[0018] In a possible implementation, fifth information from the network device is received, the fifth information being used to indicate whether the network device expects to obtain information about whether the terminal device supports independent sub-band precoding. When the fifth information indicates that the network device expects to obtain the information about whether the terminal device supports independent sub-band precoding, the terminal device sends fourth information to the network device, the fourth information being used to indicate whether the terminal device supports independent sub-band precoding.

[0019] In the embodiments of the present application, when the fourth information sent by the terminal device indicates that the terminal device supports independent sub-band precoding, the network device can send first information to the terminal device, indicating that the terminal device uses independent sub-band precoding for uplink transmission, or indicating to the terminal device that the network device uses independent sub-band precoding for downlink transmission.

[0020] In the second aspect, the embodiments of the present application provide a precoding method, which can be executed by a network device, or by a component of the network device, for example, a processor, a chip or a chip system of the network device, or by a logic module or software capable of realizing all or part of the functions of the network device.

[0021] The method provided in the second aspect includes: sending first information to a terminal device, the first information indicating the number of subbands M and the number of precoding matrices K, and the number of antenna ports N corresponding to each subband, wherein M and K are integers greater than 1, K is less than or equal to M, and N is an integer greater than or equal to 1; when receiving data from the terminal device, N is less than the number of antenna ports L of the terminal device, and L is an integer greater than 1; when sending data to the terminal device, N is less than the number of antenna ports P of the network device, and P is an integer greater than 1.

[0022] In one possible implementation, the first information is used to indicate that the precoding type used by the terminal device for uplink transmission is independent subband precoding, or the first information is used to indicate that the precoding type used by the network device for downlink transmission is independent subband precoding, wherein the precoding type includes full-band precoding, subband precoding and independent subband precoding.

[0023] In this embodiment of the application, the network device sends first information to the terminal device, enabling the terminal device to determine whether to use independent subband precoding for uplink transmission or to determine whether the network device uses independent subband precoding for downlink transmission.

[0024] The method provided in the second aspect further includes: sending second information to a terminal device, the second information being used to indicate the correspondence between M subbands and K precoding matrices, and the correspondence between each subband and N antenna ports.

[0025] In one possible implementation, subband configuration information is also sent to the terminal device. This subband configuration information is used to indicate the bandwidth of the subband, and / or the number of subbands, and / or the starting position of the subband.

[0026] In one possible implementation, a third piece of information, indicating K precoding matrices, is also sent to the terminal device. Based on the second and third pieces of information, data is received from the terminal device.

[0027] In this embodiment, the network device sends second and third information to the terminal device, enabling the terminal device to send uplink data to the network device using independent subband precoding. This reduces PAPR power back-off, which is equivalent to increasing the transmit power of the terminal device and enhancing uplink coverage.

[0028] In one possible implementation, data is sent to the terminal device based on the second message.

[0029] In this embodiment, the network device uses independent subband precoding to send downlink data to the terminal device, which can reduce PAPR power back-off, which is equivalent to increasing the transmit power of the network device and enhancing downlink coverage capability.

[0030] The method provided in the second aspect further includes: receiving fourth information from the terminal device, the fourth information being used to indicate the number of subbands M, the number of precoding matrices K, and the number of antenna ports N corresponding to each subband, wherein M and K are integers greater than 1, K is less than or equal to M, N is an integer greater than or equal to 1, N is less than the number of antenna ports L of the terminal device or N is less than the number of antenna ports P of the network device, and L and P are integers greater than 1.

[0031] In one possible implementation, a fifth message is sent to the terminal device, indicating whether the network device expects to acquire a precoding type supported by the terminal device. When the fifth message indicates that the network device expects to acquire a precoding type supported by the terminal device, a fourth message is received from the terminal device, indicating the precoding types supported by the terminal device, wherein the precoding types supported by the terminal device include full-band precoding, and / or sub-band precoding, and / or independent sub-band precoding.

[0032] In one possible implementation, a fifth message is sent to the terminal device, indicating whether the network device expects to obtain information on whether the terminal device supports independent subband precoding. When the fifth message indicates that the network device expects to obtain information on whether the terminal device supports independent subband precoding, a fourth message is received from the terminal device, indicating whether the terminal device supports independent subband precoding.

[0033] In this embodiment of the application, when the fourth information received by the network device indicates that the terminal device supports independent subband precoding, the network device can send the first information to the terminal device, instructing the terminal device to use independent subband precoding for uplink transmission, or instructing the network device to use independent subband precoding for downlink transmission.

[0034] Thirdly, this application provides a communication device that has the functions of the first aspect above. For example, the communication device includes modules, units, or means corresponding to the operations involved in the first aspect above. The modules, units, or means can be implemented by software, hardware, or a combination of software and hardware.

[0035] Fourthly, this application provides a communication device that has the functions of the second aspect above. For example, the communication device includes modules, units, or means that perform the operations involved in the second aspect above. The modules, units, or means can be implemented by software, hardware, or a combination of software and hardware.

[0036] Fifthly, this application provides a communication device comprising a memory and one or more processors. The memory stores part or all of the necessary computer programs or instructions for implementing the functions described in the first aspect above. The one or more processors are capable of executing the computer programs or instructions, which, when executed, cause the communication device to implement the methods in any possible design or implementation of the first aspect above.

[0037] In one possible design, the communication device may further include an interface circuit, wherein the processor is used to communicate with other devices or components through the interface circuit.

[0038] In one possible design, the communication device may also include the memory.

[0039] The aforementioned communication device may be a terminal, a communication module in a terminal, or a chip in a terminal that is responsible for communication functions, such as a modem chip (also known as a baseband chip) or a SoC or SIP chip that contains a modem module.

[0040] Sixthly, this application provides a communication device including a memory and one or more processors. The memory stores part or all of the computer program or instructions necessary for implementing the functions described in the second aspect above. The one or more processors are capable of executing the computer program or instructions, which, when executed, cause the communication device to implement the methods in any possible design or implementation of the second aspect above.

[0041] In one possible design, the communication device may further include an interface circuit, wherein the processor is used to communicate with other devices or components through the interface circuit.

[0042] In one possible design, the communication device may also include the memory.

[0043] The aforementioned communication device may be a base station, or a communication module in a base station, or a chip in a base station that is responsible for communication functions, such as a modem chip (also known as a baseband chip) or a SoC or SIP chip containing a modem module.

[0044] In a seventh aspect, this application provides a communication system comprising at least one terminal device and at least one network device, wherein the terminal device is configured to perform the method in any possible design of the first aspect described above, and the network device is configured to perform the method in any possible design of the second aspect described above.

[0045] Eighthly, this application provides a computer-readable storage medium storing computer-readable instructions that, when read and executed by a computer, cause the computer to perform any of the possible designs in the first and second aspects described above.

[0046] Ninthly, this application provides a computer program product that, when read and executed by a computer, causes the computer to perform any of the possible designs in the first and second aspects described above.

[0047] In a tenth aspect, this application provides a chip including a processor and a communication interface for communicating with external or internal devices, the processor for implementing the methods in any of the possible designs of the first and second aspects described above.

[0048] In one possible design, the chip may further include a memory storing computer programs or instructions, and a processor for executing the computer programs or instructions stored in the memory, or derived from other programs or instructions. When the computer program or instructions are executed, the processor implements the methods in either of the first and second aspects of the above-described design.

[0049] In one possible design, the chip can be integrated into a terminal device or a network device. Attached Figure Description

[0050] Figure 1 is a schematic diagram of a communication system provided in an embodiment of this application;

[0051] Figure 2A is a schematic diagram of a full-band precoding provided in an embodiment of this application;

[0052] Figure 2B is a schematic diagram of a sub-band precoding provided in an embodiment of this application;

[0053] Figure 3 is a flowchart illustrating an uplink independent subband precoding method provided in an embodiment of this application;

[0054] Figure 4A is a schematic diagram of uplink independent subband precoding based on a codebook according to an embodiment of this application;

[0055] Figure 4B is a schematic diagram of uplink independent subband precoding based on a non-codebook provided in an embodiment of this application;

[0056] Figure 5 is a schematic diagram of an independent sub-band precoding provided in an embodiment of this application;

[0057] Figure 6 is a flowchart illustrating a downlink independent subband precoding method provided in an embodiment of this application;

[0058] Figure 7A is a schematic diagram of a codebook-based downlink independent subband precoding provided in an embodiment of this application;

[0059] Figure 7B is a schematic diagram of a non-codebook-based downlink independent subband precoding provided in an embodiment of this application;

[0060] Figure 8 is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0061] Figure 9 is a schematic diagram of the structure of another communication device provided in an embodiment of this application;

[0062] Figure 10 is a schematic diagram of the structure of a chip provided in an embodiment of this application. Detailed Implementation

[0063] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0064] The terms "first" and "second," etc., used in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0065] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0066] In this application, "at least one (item)" refers to one or more, "more than one" refers to two or more, "at least two (items)" refers to two or three or more, and "and / or" is used to describe the correspondence between related objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0067] The system architecture of the embodiments of this application is described below:

[0068] To facilitate understanding of the technical solutions in the embodiments of this application, the system architecture of the methods provided in the embodiments of this application will be briefly described below. It is understood that the system architecture described in the embodiments of this application is for the purpose of more clearly illustrating the technical solutions in the embodiments of this application and does not constitute a limitation on the technical solutions provided in the embodiments of this application.

[0069] The technical solutions of this application embodiment can be applied to various communication systems, such as satellite communication systems and traditional mobile communication systems. The satellite communication system can be integrated with traditional mobile communication systems (i.e., terrestrial communication systems). Examples of communication systems include: wireless local area network (WLAN) communication systems, wireless fidelity (WiFi) systems, long term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, LTE time division duplex (TDD) systems, 5th generation (5G) systems, or new radio (NR) systems, and other future communication systems. It also supports communication systems that integrate multiple wireless technologies. For example, it can also be applied to systems that integrate non-terrestrial networks (NTN) with terrestrial mobile communication networks, such as drones, satellite communication systems, and high altitude platform station (HAPS) communication.

[0070] Figure 1 illustrates an example of a communication system applicable to embodiments of this application. The communication system includes at least one network device and at least one terminal device. Figure 1 uses a network device and multiple terminal devices as examples. These multiple terminal devices can be cellular phones, smartphones, laptops, handheld communication devices, handheld computing devices, satellite radio devices, global positioning systems, personal digital assistants (PDAs), and / or any other suitable devices for communication over a wireless communication system, and all can be connected to the network device. These multiple terminal devices are all capable of communicating with the network device; in addition, communication between terminal devices is also possible. Of course, the number of terminal devices and network devices shown in Figure 1 is merely an example, and there may be fewer or more.

[0071] The terminal device involved in the embodiments of this application, which can also be simply referred to as a terminal, is an entity on the user side used to receive or transmit signals. A terminal device can be a device that provides voice and / or data connectivity to a user, such as a handheld device with wireless connectivity, an in-vehicle device, etc. A terminal device can also be other processing devices connected to a wireless modem. The terminal device can communicate with a radio access network (RAN). A terminal device can also be called a wireless terminal, subscriber unit, subscriber station, mobile station, mobile station, remote station, access point, remote terminal, access terminal, user terminal, user agent, user equipment, or UE, etc. A terminal device can be a mobile terminal, such as a mobile phone (or "cellular" phone) and a computer with a mobile terminal, for example, a portable, pocket-sized, handheld, computer-embedded, or in-vehicle mobile device that exchanges voice and / or data with the radio access network. For example, the terminal device can also be a personal communication service (PCS) telephone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), or other similar devices. Common terminal devices include mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), and wearable devices such as smartwatches, smart bracelets, and pedometers, but the embodiments in this application are not limited to these.

[0072] The embodiments of this application do not limit the device form of the terminal device. The device used to implement the function of the terminal device can be the terminal device itself; it can also be a device that supports the terminal device in implementing the function, such as a chip system. The device can be installed in the terminal device or used in conjunction with the terminal device. In the embodiments of this application, the chip system can be composed of chips or can include chips and other discrete components.

[0073] A network device is an entity on the network side used to transmit signals, or receive signals, or both. A network device can be a means deployed in a radio access network (RAN) to provide wireless communication functionality to terminals.

[0074] In one possible scenario, network equipment can be devices with base station functions, such as evolved NodeBs (eNodeBs), transmitting and receiving points (TRPs), transmitting points (TPs), next-generation NodeBs (gNBs), next-generation base stations in future mobile communication systems, integrated access and backhaul (IAB) nodes, and non-terrestrial network equipment, i.e., equipment that can be deployed on high-altitude platforms or satellites. Network equipment can also be transmitting and receiving points (TRPs), base stations, and various forms of control nodes, such as network controllers and wireless controllers. Specifically, network equipment can be various forms of macro base stations, micro base stations (also known as small cells) in heterogeneous network (HetNet) scenarios, relay stations, access points (APs), radio network controllers (RNCs), node Bs (NBs), base station controllers (BSCs), base transceiver stations (BTSs), home base stations (e.g., home evolved node Bs, or home node Bs (HNBs)), baseband units (BBUs) and remote radio units (RRUs) in distributed base station scenarios, transmitting and receiving points (TRPs), transmitting points (TPs), mobile switching centers, etc., and can also be base station antenna panels. Control nodes can connect to multiple base stations and configure resources for multiple terminals covered by multiple base stations. In systems employing different wireless access technologies, the names of devices with base station functions may differ. For example, it could be a gNB in ​​5G, or a network-side device in a network after 5G, or a network device in a future evolved public land mobile network (PLMN) network, or a device that performs base station functions in device-to-device (D2D) communication, machine-to-machine (M2M) communication, or vehicle-to-everything (V2X) communication, etc. This application does not limit the specific name of the network device.Network equipment can also be open RAN (O-RAN or ORAN), baseband pool (BBU pool) and RRU under cloud radio access network (CRAN), etc.

[0075] In another possible scenario, multiple network devices collaborate to assist terminals in achieving wireless access, with each network device performing a portion of the base station's functions. For example, network devices may include a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). CUs and DUs can be separate entities or included in the same network element, such as a baseband unit (BBU). RUs may be included in radio equipment or radio units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs). It is understood that network devices can be CU nodes, DU nodes, or devices comprising both CU and DU nodes. Furthermore, CUs can be classified as network devices in the access network (RAN) or the core network (CN), without limitation.

[0076] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0077] In this embodiment, the form of the network device is not limited. The device used to implement the function of the network device can be the network device itself, or it can be a device that supports the network device in implementing the function, such as a chip system. The device can be installed in the network device or used in conjunction with the network device.

[0078] The following introduces several concepts that may be involved in this application.

[0079] (a) Precoding

[0080] For a multi-antenna transmission model, assume the number of antennas at the transmitting end is m, the number of antennas at the receiving end is n, and the data column vector at the transmitting end is X = [x1, x2, ..., xn]. m ] T The data column vector at the receiving end is Y = [y1, y2, ..., y]. n ] T Here, "T" represents the transpose operation of a vector or matrix. The relationship between the transmitting data X and the receiving data Y can be expressed as: Y = HX

[0081] Here, H is an n*m matrix, and each element in the matrix is ​​the spatial channel characteristic of each pair of transmit and receive antennas. Therefore, H is the channel matrix of this multi-antenna model.

[0082] Performing SVD (singular value decomposition) on the channel matrix H yields: H=UΣV*

[0083] Where Σ is an n*m diagonal matrix, that is, matrix Σ has a number of non-zero elements on the diagonal, and all other elements are 0, and the number of non-zero elements on the diagonal is the rank of the channel matrix H; U and V are n*n and m*m unitary matrices respectively. Multiplying a unitary matrix by its conjugate transpose yields an identity matrix; * denotes the conjugate transpose of the matrix.

[0084] Singular value decomposition (SVD) of the channel matrix can simplify a complex channel matrix into a simpler one. The receiver can then perform equalization on each channel in the channel matrix H to eliminate the correlation between channels. Therefore, if the channel matrix before equalization at the receiver is a simplified version, the implementation complexity of the receiver can be significantly reduced.

[0085] Based on the aforementioned relationship between the data sent and received, we can obtain: Y = HX = UΣV * X

[0086] Further utilizing the characteristics of unitary matrices, the column vectors are multiplied by V before being sent at the transmitting end. * The conjugate transpose of the matrix V, i.e., X = VX', is multiplied by the conjugate transpose of U at the receiving end, U*. Then the above equation can be expressed as: Y' = U * Y = U * HX = U * UΣV * VX'=ΣX'

[0087] The transformation results above show that the receiving end performs some processing on the received signal (multiplying by U). * Then, channel equalization can be performed according to a relatively simple channel matrix model Σ, thereby recovering the original signal X' from the transmitter.

[0088] The basic steps of the above method are illustrated below:

[0089] 1. The transmitting end and the receiving end each obtain the channel matrix H;

[0090] 2. The relationship between matrix H and matrix Σ is obtained through SVD decomposition, i.e., H = UΣV * ;

[0091] 3. Before transmitting data X', the transmitting end multiplies X' by matrix V, i.e., X = VX', and then transmits it through the antenna;

[0092] 4. The receiving end receives data Y, where Y = HX;

[0093] 5. The receiving end multiplies Y by matrix U. * , that is, Y'=U * Y;

[0094] 6. Based on the result of Y', perform channel equalization according to the channel matrix model Σ to recover the original transmitted data X'.

[0095] In step 3 above, the original signal X' from the transmitting end has undergone some preprocessing before being transmitted by the antenna, namely, multiplying by matrix V. This preprocessing process is called precoding, and matrix V is called the precoding matrix. Precoding can improve the transmission capacity of a multi-antenna system, reduce the decoding complexity at the receiving end, and improve the directivity of the beam.

[0096] The following introduces several concepts involved in precoding:

[0097] 1. Layer mapping

[0098] Each codeword stream is divided into multiple data streams of equal length to prepare data for subsequent multi-stream parallel transmission at multiple antenna ports. These data streams of equal length are called layers, and the number of data streams is called the stream number, also known as the layer number. The layer number is strongly correlated with the channel characteristics between the transmitter and receiver, and the rank of the channel matrix represents the maximum number of layers that can be transmitted in that channel space.

[0099] 2. Antenna port mapping

[0100] An antenna port is defined as a channel that data on an OFDM symbol traverses when transmitted through that port, and that the channel traversed is the same as that traversed by data on other OFDM symbols transmitted through that same port. Simply put, an antenna port is a logical concept, not a physical one; an antenna port and a physical antenna are different. One antenna port can correspond to one physical antenna, or it can correspond to multiple physical antennas.

[0101] Each antenna port represents a channel model, which can be derived from a reference signal transmitted through that antenna port. Therefore, each antenna port corresponds to a specific reference signal. The receiver can perform channel estimation based on this specific reference signal, and the result of the channel estimation can be used to receive other signals emitted by that antenna port.

[0102] Antenna port mapping maps layer vectors to antenna ports, allowing the receiver to estimate the channel conditions at the antenna port using the DMRS (demodulation reference signal), thus enabling it to correctly receive and demodulate data transmitted through that antenna port.

[0103] 3. PMI (precoding matrix indication)

[0104] To reduce indication overhead, the 3GPP (3rd Generation Partnership Project) protocol defines a finite number of precoding matrices, also known as codebooks, and assigns numbered indexes to the precoding matrices within them. The PMI (Precoding Matrix Indicator) can be used to indicate the index of the codebook. Specifically, to distinguish it from the downlink PMI, the uplink PMI is also called TPMI (Transmitted Precoding Matrix Indicator).

[0105] (II) Full-band precoding and sub-band precoding

[0106] Taking the uplink as an example, full-band corresponds to all frequency domain resources allocated to the uplink signal. Taking the Precoding Matrix Indication Information (PMI) as an example, if a network device indicates a full-band precoding matrix indication to a terminal device, the precoding matrix indicated by this information is used for all frequency domain resources of the uplink signal. In this embodiment, full-band precoding refers to using the same precoding matrix for all frequency domain resources of the uplink signal, and the uplink signal is transmitted through all antenna ports of the terminal device.

[0107] A subband is a portion of the frequency domain resources allocated to the uplink signal. A subband can include multiple consecutive RBs (physical resource blocks) or multiple consecutive RBGs (resource block groups), or it can include multiple non-consecutive RBs or multiple non-consecutive RBGs. Taking the Precoding Matrix Indication Information (PMI) as an example, if a network device indicates precoding matrix indication information about a certain subband to a terminal device, the precoding matrix indicated by this information is used for the frequency domain resources corresponding to that subband for the uplink signal. In this embodiment, subband precoding means that the uplink signal can use precoding matrices separately in different subbands. The precoding matrices used in each subband can be the same or different, and the uplink signal is transmitted through all antenna ports of the terminal device. That is, the network device can indicate precoding matrices separately for each subband, rather than using the same precoding matrix for all frequency domain resources of the uplink signal.

[0108] Figures 2A and 2B are schematic diagrams of full-band precoding and sub-band precoding, respectively. Assume the frequency domain resources scheduled by the network device include four sub-bands, with each square representing one sub-band. As shown in Figure 2A, the channel matrix H corresponding to this frequency domain resource, after SVD decomposition, yields the precoding matrix V. That is, the uplink signal uses the same precoding matrix V on this frequency domain resource, and the uplink signal is transmitted through all antenna ports of the terminal device. As shown in Figure 2B, the channel matrices H1, H2, H3, and H4 corresponding to the four sub-bands, after SVD decomposition, yield precoding matrices V1, V2, V3, and V4, respectively. That is, the uplink signal uses four precoding matrices V1, V2, V3, and V4 on the four sub-bands, and the uplink signal is transmitted through all antenna ports of the terminal device.

[0109] Due to the limited uplink transmit power of terminal devices and the high PAPR of OFDM waveforms, uplink power needs to be backed up. This limits the uplink coverage capability of NR, making it unable to support high-data-volume, low-latency, and high-reliability services (such as XR and intelligent robots). In existing wireless communication systems, such as LTE and NR systems, uplink MIMO transmission only supports wideband precoding. Considering the frequency selectivity of the channel, multiple subbands sharing a single precoding matrix results in poor precoding performance. To improve coverage, each subband can use its own precoding matrix, i.e., subband precoding. However, although subband precoding can improve precoding performance, it increases PAPR, causing the transmit power of terminal devices to be further backed up, further degrading uplink coverage.

[0110] To address the aforementioned technical problems, this application provides the following communication method to improve the uplink coverage capability of terminal devices. This application uses the PUSCH (physical uplink shared channel) signal as an example for illustration. It can be understood that the uplink signals applicable to the communication method provided in this application include, but are not limited to, PUSCH signals, DMRS signals, PUCCH (physical uplink control channel) signals, PRACH (physical random access channel) signals, SRS (sounding reference signal) signals, and PTRS (phase tracking reference signal) signals.

[0111] As shown in Figure 3, Figure 3 is a flowchart illustrating an uplink independent subband precoding method provided in an embodiment of this application. The communication method includes the following steps:

[0112] S301. The network device sends first information, which indicates the number of subbands M, the number of precoding matrices K, and the number of antenna ports N corresponding to each subband.

[0113] This application provides a precoding method different from full-band precoding and sub-band precoding, which can be called independent sub-band precoding. In the independent sub-band precoding method, M sub-bands correspond to K precoding matrices, and each sub-band corresponds to N antenna ports of the terminal device. Here, M and K are integers greater than 1, and K is less than or equal to M, meaning that different sub-bands can correspond to different or the same precoding matrices. N is an integer greater than or equal to 1, and N is less than the number of antenna ports L of the terminal device, where L is an integer greater than 1, meaning that data on each sub-band can be transmitted on some antenna ports of the terminal device.

[0114] In one possible implementation, the first information indicates the number of subbands M, the number of precoding matrices K, and the number of antenna ports N corresponding to each subband, where M and K are integers greater than 1, K is less than or equal to M, N is an integer greater than or equal to 1, and N is less than L. After receiving the first information, the terminal device can determine that independent subband precoding will be used for uplink transmission based on the values ​​of M, K, and N, the relationship between M and K, and the relationship between N and L.

[0115] In one possible implementation, the first information is used to indicate that the precoding type used by the terminal device for uplink transmission is independent subband precoding. The precoding types include full-band precoding, subband precoding, and independent subband precoding. For full-band precoding, M and K equal 1, and N equals L; for subband precoding, M and K are integers greater than 1, K is less than or equal to M, and N equals L; for independent subband precoding, M and K are integers greater than 1, K is less than or equal to M, N is an integer greater than or equal to 1, and N is less than L.

[0116] In one possible implementation, the first information may include a first field, which is used to indicate different precoding methods.

[0117] Optionally, the first field may include one bit, the bit state of which can be used to indicate independent subband precoding.

[0118] For example, bit "0" can represent independent subband precoding, bit "1" can represent subband precoding, and the absence of this bit can represent full-band precoding. In this case, one bit in the first field is set to "0".

[0119] For example, bit "0" can represent subband precoding, bit "1" can represent independent subband precoding, and the absence of this bit can represent full-band precoding. In this case, one bit in the first field is set to "1".

[0120] For example, bit "0" can represent full-band precoding, bit "1" can represent sub-band precoding, and the absence of this bit can represent independent sub-band precoding. Therefore, the first field does not include this 1 bit.

[0121] It is understood that the embodiments of this application do not limit the mapping relationship between the bit state of the above-mentioned 1 bit and different precoding methods.

[0122] Optionally, the first field may include at least two bits, the bit state of which can be used to indicate different precoding methods.

[0123] For example, the first field may include 2 bits, where bit "00" represents independent subband precoding, bit "01" represents subband precoding, and bit "10" represents full-band precoding. In this case, the 2 bits in the first field are set to "00".

[0124] For example, the first field may include 2 bits, where bit "00" represents full-band precoding, bit "01" represents sub-band precoding, and bit "10" represents independent sub-band precoding. In this case, the 2 bits in the first field are set to "10".

[0125] It is understood that the first field may also include more bits (e.g., 3 bits, 4 bits, etc.), and this application embodiment does not limit this. Furthermore, this application embodiment does not limit the mapping relationship between at least 2 bits of bit state and different precoding methods.

[0126] Optionally, the first field may include at least 3 bits, and the bitmap consisting of at least 3 bits can be used for different precoding methods.

[0127] For example, the first field may include 3 bits, where bit "001" represents independent subband precoding, bit "010" represents subband precoding, and bit "100" represents full-band precoding. In this case, the 3 bits in the first field are set to "001".

[0128] For example, the first field may include 3 bits, where bit "001" represents full-band precoding, bit "010" represents sub-band precoding, and bit "100" represents independent sub-band precoding. In this case, the 3 bits in the first field are set to "100".

[0129] It is understood that the first field may also include more bits (e.g., 4 bits, 5 bits, etc.), and this application embodiment does not limit this. Furthermore, this application embodiment does not limit the mapping relationship between a bitmap consisting of at least 3 bits and different precoding methods.

[0130] Optionally, the first information can be a system message, such as the SIB1 (system information block 1) message.

[0131] Optionally, the first information may be radio resource control (RRC) signaling.

[0132] Optionally, the first information may be a media access control element (MAC CE) command.

[0133] Optionally, the first information can be DCI (downlink control information) information.

[0134] S302. The network device sends second information, which indicates the correspondence between M subbands and K precoding matrices, and the correspondence between each subband and N antenna ports.

[0135] The network device can send second information to the terminal device. After receiving the second information, the terminal device can determine the correspondence between M subbands and K precoding matrices, as well as the correspondence between each subband and N antenna ports.

[0136] In one possible implementation, the correspondence between the M subbands and K precoding matrices, and the correspondence between each subband and N antenna ports, can be represented in a table. Tables 1 to 4 provide four possible examples of correspondences. The M subbands can be arranged in ascending or descending order of frequency, or the order of the M subbands can be predefined; this embodiment does not limit this. The index of the precoding matrix can be a PMI or the sequence number of the K precoding matrices indicated by the network device; this embodiment does not limit this. After receiving the above table, the terminal device can determine the precoding matrix and antenna ports corresponding to each subband.

[0137] Assume the terminal device has 4 antenna ports. Table 1 provides a one-to-one correspondence between the 4 subbands, 4 precoding matrices, and 4 antenna ports. Different subbands correspond to different precoding matrices and different antenna ports. For example, subbands #1, #2, #3, and #4 correspond to precoding matrices #1, #2, #3, and #4, and antenna ports #1, #2, #3, and #4, respectively.

[0138] Table 1

[0139] Table 2 provides a correspondence between 4 subbands, 3 precoding matrices, and 4 antenna ports. Different subbands correspond to different antenna ports. For example, subbands #1, #2, #3, and #4 correspond to antenna ports #1, #2, #3, and #4, respectively. Different subbands can correspond to the same or different precoding matrices. For example, subbands #1 and #2 correspond to the same precoding matrix #1, and subbands #3 and #4 correspond to precoding matrices #2 and #3, respectively.

[0140] Table 2

[0141] Table 3 provides a correspondence between 4 subbands, 4 precoding matrices, and 4 antenna ports. Different subbands correspond to different precoding matrices. For example, subbands #1, #2, #3, and #4 correspond to precoding matrices #1, #2, #3, and #4, respectively. Each subband can correspond to one or more (but less than 4) antenna ports, and different subbands can correspond to the same or different antenna ports. For example, subband #1 corresponds to antenna ports #1 and #2, subband #2 corresponds to antenna ports #2 and #3, and subbands #3 and #4 correspond to the same antenna port #4.

[0142] Table 3

[0143] Table 4 provides a correspondence between 4 subbands, 3 precoding matrices, and 4 antenna ports. Different subbands can correspond to the same or different precoding matrices. For example, subband #1 and subband #2 correspond to the same precoding matrix #1, and subband #3 and subband #4 correspond to precoding matrices #2 and #3, respectively. Each subband can correspond to one or more (but less than 4) antenna ports, and different subbands can correspond to the same or different antenna ports. For example, subband #1 corresponds to antenna ports #1 and #2, subband #2 corresponds to antenna ports #2 and #3, and subband #3 and subband #4 correspond to the same antenna port #4.

[0144] Table 4

[0145] Understandably, the correspondence between M subbands and K precoding matrices, and the correspondence between each subband and N antenna ports, is not limited to the above four possible examples, and the embodiments of this application do not limit this.

[0146] Understandably, the correspondence between the M subbands and K precoding matrices, and the correspondence between each subband and N antenna ports, is not limited to a tabular representation. For example, it can also be represented as a list, a pair type, or other methods. This application embodiment does not limit this. For the pair type, the above correspondence can be represented as {subband index, precoding matrix index, antenna port index}. This application embodiment does not limit the order of the subband index, precoding matrix index, and antenna port index in the pair type.

[0147] Optionally, the second information can be a system message, such as an SIB1 message.

[0148] Optionally, the second information may be Radio Resource Control (RRC) signaling.

[0149] Optionally, the second information may be a Media Access Control (MAC) CE command.

[0150] Optionally, the second information can be DCI information.

[0151] Understandably, the second information sent by the network device to the terminal device can be the same information as the first information, or it can be different information. For example, the second information and the first information can be the same RRC signaling or different RRC signaling. This application embodiment does not limit this.

[0152] Understandably, the second information sent by the network device to the terminal device may be sent simultaneously or at different times, and this application embodiment does not limit this.

[0153] To determine the frequency domain location and bandwidth of the M sub-bands, network devices can also send sub-band configuration information to terminal devices.

[0154] In one possible implementation, for subband division based on continuous RB or continuous RBG, a uniform division method can be adopted. The subband configuration information can include the subband bandwidth, which can also be called the subband bandwidth.

[0155] Optionally, the granularity of the subband bandwidth can be RB, in which case the subband bandwidth refers to the number of consecutive RBs occupied by the subband in the frequency domain.

[0156] Optionally, the granularity of the subband bandwidth can also be RBG, in which case the subband bandwidth is the number of consecutive RBGs occupied by each subband in the frequency domain.

[0157] Optionally, the subband bandwidth can be related to the number Q of physical resources scheduled by the network device, where the number of physical resources can be the number of RBs or the number of RBGs. Different Qs can correspond to different subband bandwidths, or different Qs can correspond to the same subband bandwidth, or the same Q can correspond to multiple subband bandwidths. The specific subband bandwidth used can be configured by the network device. When Q is a fixed value, the subband bandwidth is also a fixed value.

[0158] Optionally, subband bandwidth can be related to system bandwidth, but not to the number Q of physical resources scheduled by the network device. One type of system bandwidth can correspond to one type of subband bandwidth, or one type of system bandwidth can correspond to multiple types of subband bandwidth, and which subband bandwidth is used can be configured by the network device. When the system bandwidth is a fixed value, the subband bandwidth is also a fixed value.

[0159] There are several ways to indicate subband bandwidth.

[0160] Optionally, network devices can indicate subband bandwidth to terminal devices via RRC signaling. For example, subband bandwidth can be explicitly indicated by adding a "subband bandwidth" system parameter to the RRC signaling; alternatively, subband bandwidth can be implicitly indicated by indicating a specific system bandwidth or other system parameter based on a mapping table between a defined system bandwidth or other system parameters and subband bandwidth.

[0161] Optionally, network devices can indicate subband bandwidth to terminal devices via system messages, MAC CE commands, or DCI information. The methods for explicitly or implicitly indicating subband bandwidth can be found in the above description and will not be repeated here.

[0162] Optionally, the sub - band bandwidth can also be predefined or pre - configured.

[0163] The sub - band configuration information may further include the starting position of the sub - band. The starting position of the sub - band can be the index of the RB or the index of the RBG corresponding to the starting position of the frequency - domain resource scheduled by the network device. Or the starting position of the sub - band can be the index of the RB or the index of the RBG corresponding to the ending position of the frequency - domain resource scheduled by the network device. Or the starting position of the sub - band can be the index of the RB or the index of the RBG corresponding to the middle position of the frequency - domain resource scheduled by the network device. The embodiments of the present application do not limit this.

[0164] Taking the sub - band division based on consecutive RBs as an example, assume that the starting position of the sub - band is the index of the RB corresponding to the starting position of the frequency - domain resource scheduled by the network device. The terminal device receives the sub - band configuration information. According to the sub - band bandwidth (assumed to be B) and the starting position of the sub - band (assuming the corresponding RB index is S0), the starting positions and bandwidths of M sub - bands can be determined: The starting position of the m - th sub - band is S m = S0 + m * B, and the bandwidth is B, where 0 <= m <= M - 1, Q is the number of RBs included in the frequency - domain resource scheduled by the network device, is the floor operation.

[0165] When Q cannot be divided evenly by B, it can be that the bandwidth of sub - band #0 is greater than B, or it can also be that the bandwidth of sub - band #M - 1 is greater than B, or it can also be that the bandwidth of the sub - band with sub - band index m satisfying 0 < m < M - 1 is greater than B. The embodiments of the present application do not limit this.

[0166] It should be noted that the above method also applies to the sub - band division based on consecutive RBGs and will not be elaborated here.

[0167] In a possible implementation, for the sub - band division based on consecutive RBs or consecutive RBGs, a uniform division method can be adopted. The sub - band configuration information includes the number M of sub - bands, which can also be referred to as the number M of sub - bands.

[0168] Optionally, the number M of sub - bands can be related to the number Q of physical resources scheduled by the network device, or it can also be unrelated to the number Q of physical resources scheduled by the network device and related to the system bandwidth. Refer to the foregoing description of the sub - band bandwidth and will not be elaborated here.

[0169] Optionally, the network device can indicate the number M of sub - bands to the terminal device through system messages, RRC signaling, MAC CE commands or DCI information. The method of explicitly or implicitly indicating the number M of sub - bands can refer to the foregoing description of indicating the sub - band bandwidth B and will not be elaborated here. Optionally, the number M of sub - bands can also be predefined or pre - configured.

[0170] The sub-band configuration information may further include the starting position of the sub-band. The starting position of the sub-band may refer to the foregoing description and will not be elaborated herein.

[0171] Taking the sub-band division based on consecutive RBs as an example, assume that the starting position of the sub-band is the index of the RB corresponding to the starting position of the frequency-domain resources scheduled by the network device. After receiving the sub-band configuration information, the terminal device can determine the starting positions and bandwidths of the M sub-bands according to the number of sub-bands M and the starting position of the sub-band (assuming the corresponding RB index is S0): the starting position of the m-th sub-band is S m = S0 + m * B, where 0 <= m <= M - 1, and the bandwidth

[0172] When Q cannot be divided evenly by M, it can be that the bandwidth of sub-band #0 is greater than Or it can also be that the bandwidth of sub-band #M - 1 is greater than Or it can also be that the bandwidth of the sub-bands with sub-band index m satisfying 0 < m < M - 1 is greater than The embodiments of this application do not make any limitations in this regard.

[0173] It should be noted that the above method is equally applicable to the sub-band division based on consecutive RBGs and will not be elaborated herein.

[0174] In a possible implementation manner, for the sub-band division based on consecutive RBs or consecutive RBGs, a non-uniform division method can be adopted. Exemplarily, the network device may send M sub-band configuration information to the terminal device. Each sub-band configuration information may be an SLIV (start and length indicator value). A possible calculation formula for an SLIV is as follows: if (L - 1) <= 7 SLIV = 14 * (L - 1) + S else SLIV = 14 * (14 - L + 1) + (14 - 1 - S)

[0175] Where, S represents the starting position of the sub-band, L represents the sub-band width. The starting position of the sub-band can be represented by the RB index, and the sub-band width can be represented by the number of RBs.

[0176] After receiving the M SLIV values, the terminal device can obtain the starting position S and sub-band width L of each sub-band according to the above calculation formula of the SLIV. For example, if the network device indicates the SLIV values {14, 16, 74} corresponding to 3 sub-bands, the terminal device can determine:

[0177] For SLIV = 14, S = 0, L = 2, that is, the starting position of sub-band #0 is RB#0, and the bandwidth is 2 RBs;

[0178] SLIV=16 corresponds to S=2, L=2, that is, the starting position of subband #1 is RB#2, and the bandwidth is 2 RBs;

[0179] SLIV=74 corresponds to S=4, L=6, that is, the starting position of subband #2 is RB#4, and the bandwidth is 6 RBs.

[0180] It should be noted that the above method is also applicable to subband partitioning based on continuous RBG, which will not be elaborated here.

[0181] In one possible implementation, the subband partitioning based on non-contiguous RBs or non-contiguous RBGs can be done as follows. Taking subband partitioning based on non-contiguous RBGs as an example, assuming 8 RBGs are divided into 2 subbands, the network device can send a bitmap consisting of 8 bits to the terminal device, where each bit corresponds to one RBG. Bit "0" indicates that the RBG corresponding to this bit belongs to subband #0, and bit "1" indicates that the RBG corresponding to this bit belongs to subband #1. Assuming 8 RBGs are divided into 4 subbands, the network device can send a bitmap consisting of 16 bits to the terminal device, where every 2 bits correspond to one RBG. Bit "00" indicates that the 2 bits corresponding to this RBG belong to subband #0, bit "01" indicates that the 2 bits corresponding to this RBG belong to subband #1, bit "10" indicates that the 2 bits corresponding to this RBG belong to subband #2, and bit "11" indicates that the 2 bits corresponding to this RBG belong to subband #3.

[0182] It should be noted that the above method is also applicable to subband partitioning based on non-continuous RBs, which will not be elaborated here.

[0183] Understandably, the subband configuration information and the second information sent by the network device to the terminal device can be the same information or different information. For example, the subband configuration information and the second information can be the same RRC signaling or different RRC signaling. This application embodiment does not limit this.

[0184] Understandably, the subband configuration information and the second information sent by the network device to the terminal device can be sent simultaneously or not simultaneously, and this application embodiment does not limit this.

[0185] S303. The network device sends a third message, which is used to indicate K precoding matrices.

[0186] Precoding can be categorized into codebook-based precoding and non-codebook-based precoding, depending on whether a predefined codebook is used. Codebook-based precoding is suitable for both FDD and TDD systems, and the precoding matrix is ​​derived from a predefined codebook. Non-codebook-based precoding is suitable for TDD systems. The transmitter uses a reference signal and the reciprocity of the uplink and downlink channels in the TDD system to obtain channel state information, i.e., the channel matrix. The precoding matrix can then be obtained by performing SVD decomposition on the channel matrix.

[0187] Assume the network devices have 64 antennas and the terminal devices have 4 antennas, i.e., m = 64 and n = 4. Furthermore, assume the uplink channel matrix H... ul The rank is 2, meaning that the terminal device can transmit a maximum of two streams of data.

[0188] In one possible implementation, the terminal device can employ codebook-based uplink independent subband precoding, as shown in Figure 4A, including:

[0189] 1. The terminal device sends an uncoded SRS signal to the network device.

[0190] Optionally, the terminal device can transmit SRS signals using an antenna rotation method. For example, the terminal device can transmit SRS signals on four antennas in turn, selecting one antenna to transmit at a time; or, for another example, the terminal device can transmit SRS signals on four antennas in turn, selecting two antennas to transmit at a time.

[0191] Optionally, the terminal device can transmit SRS signals in a non-antenna round-robin manner. For example, the terminal device can transmit SRS signals to the network device by fixing one antenna; or, for another example, the terminal device can transmit SRS signals to the network device by fixing two antennas.

[0192] 2. The network device selects K PMIs from a predefined codebook based on the measurement results of the SRS signal.

[0193] For terminal devices using antenna round-robin transmission, the network device can obtain uplink channel matrix information in all dimensions, meaning that the network device's uplink channel estimation is more accurate. For terminal devices not using antenna round-robin transmission, the network device can obtain uplink channel matrix information in only some dimensions.

[0194] Assuming the terminal device transmits SRS signals using an antenna-round-robin method, the network device can obtain the uplink channel matrix H corresponding to each subband after measuring the SRS signal. ul H ul The dimension is 64*4, where 64 is the number of receiving antennas of the network device and 4 is the number of transmitting antennas of the terminal device.

[0195] The network device provides the uplink channel matrix H for each sub-band. ul SVD decomposition can yield H ul =U ul Σ ul V ul * , where Σ ul It is a 64*4 diagonal matrix, U ul and V ul These are unitary matrices of 64x64 and 4x4 respectively. Since the uplink channel matrix H... ul The rank of Σ is 2, i.e., Σ ul If there are two non-zero elements on the diagonal, then the network device can determine that the appropriate uplink transmission layer number on the current channel is 2. Assume Σ ul If the two non-zero elements on the diagonal are the first two elements on the diagonal, then the precoding matrix W corresponding to that subband can be obtained. PM W PM By V ul The first two columns of elements form the matrix, which has a dimension of 4*2. Performing the above operation on M subbands yields M precoding matrices W. PM .

[0196] It should be noted that the above method also applies to situations where the terminal device transmits SRS signals using a non-antenna round-robin method, which will not be elaborated upon here.

[0197] Assuming the protocol defines G codebooks, network devices can use M precoding matrices W. PM Select K suitable codebooks W from the G codebooks defined in the protocol. PMI The K codebooks W PMI It can be indicated by K PMIs, where K is less than or equal to G. Since multiple precoding matrices W may exist... PM Corresponding to the same codebook W PMI Therefore, K is less than or equal to M.

[0198] 3. The network device sends K PMIs to the terminal device through the uplink scheduled DCI information.

[0199] The third piece of information can be DCI information used for uplink scheduling, such as DCI format 0_0, DCI format 0_1, or DCI format 0_2. The DCI information sent by the network device to the terminal device may include K PMIs, which instruct the network device to select K codebooks W from the G codebooks defined by the 3GPP protocol. PMI .

[0200] In one possible implementation, the terminal device can also employ uplink independent subband precoding based on a non-codebook, as shown in Figure 4B, including:

[0201] 1. Network devices send CSI-RS (channel state information reference signal) signals to terminal devices.

[0202] Assuming the CSI-RS has 32 ports, and since the network device has 64 antennas, the network device can use a weight matrix W with dimensions 64*32. CSI-RS The weight matrix W maps the CSI-RS signals on 32 ports onto 64 antennas and transmits them to the terminal device. CSI-RS It can be called the CSI-RS weight matrix.

[0203] 2. Based on the measurement results of the CSI-RS signal, the terminal equipment calculates the candidate precoding matrix using the reciprocity of the uplink and downlink channels.

[0204] Since the terminal device can identify up to 32 CSI-RS ports, the downlink channel matrix H obtained by the terminal device through measuring the CSI-RS signals... dl The dimension is 4*32, where 32 represents the number of CSI-RS ports and 4 represents the number of receiving antennas on the terminal device. The terminal device, based on the reciprocity of the uplink and downlink channels, performs calculations on the downlink channel matrix H. dl By performing a transpose operation, we can obtain a 32*4 uplink channel matrix H. ul .

[0205] The terminal device has an uplink channel matrix H for each sub-band. ul SVD decomposition can yield H ul =U ul Σ ul V ul * , where Σ ul It is a 32*4 diagonal matrix, U ul and V ul The uplink channel matrix H consists of 32x32 and 4x4 unitary matrices respectively. ul The rank of Σ is 2, i.e., Σ ul There are two non-zero elements on the diagonal, meaning that when a terminal device transmits two streams of data, its layer mapping will map to two PUSCH ports. Assume Σ ul If the two non-zero elements on the diagonal are the first two elements on the diagonal, then the precoding matrix W corresponding to that subband can be obtained. PM W PM By V ul It consists of the first two columns of elements, with a dimension of 4*2.

[0206] For each subband, the terminal device can determine at least one candidate precoding matrix. The at least one candidate precoding matrix corresponding to different subbands can be different or the same.

[0207] 3. The terminal device sends a pre-coded SRS signal to the network device.

[0208] For each subband, the network device can configure one SRS resource set for uplink CSI (channel state information report) acquisition for the terminal device, including 1 to 4 SRS resources, each SRS resource corresponding to one SRS signal. For each subband, the terminal device precodes each SRS signal in the subband and then transmits it to the network device, where different SRS signals correspond to different candidate precoding matrices.

[0209] 4. The network device determines the uplink precoding matrix based on the measurement results of the SRS signal.

[0210] For each subband, the network device measures one or more SRS signals, selects the SRS signal with the highest received signal quality based on the measurement results, and determines the precoding matrix corresponding to that SRS signal as the precoding matrix for that subband. Performing the above operation on M subbands yields M precoding matrices W. PM .

[0211] Optionally, the above-mentioned signal quality can be characterized by reference signal received power (RSRP), reference signal received quality (RSRQ), signal to interference plus noise ratio (SINR), etc., and the embodiments of this application do not limit this.

[0212] 5. The network device sends the uplink precoding matrix to the terminal device in the form of SRI (SRS resource indicator) through the uplink scheduling DCI information.

[0213] The third piece of information can be DCI information used for uplink scheduling, such as DCI format 0_0, DCI format 0_1, or DCI format 0_2. The DCI information sent by the network device to the terminal device may include SRS resource indications, indicating M SRS resources. The precoding matrix corresponding to these M SRS resources is the precoding matrix indicated by the network device. For uplink independent subband precoding based on non-codebook, K equals M.

[0214] Understandably, the third information sent by the network device to the terminal device and the second information, or the third message and the first message, may be the same information or different information. This application embodiment does not limit this.

[0215] Understandably, the third information and the second information, or the third message and the first message, sent by the network device to the terminal device can be sent simultaneously or not simultaneously, and this application embodiment does not limit this.

[0216] S304. The terminal device sends uplink data.

[0217] After receiving the second and third information, the terminal device can precode the uplink data based on the correspondence between K precoding matrices, M subbands and K precoding matrices, as well as the correspondence between each subband and N antenna ports, and then send it to the network device.

[0218] In one possible implementation, the terminal device uses codebook-based independent subband precoding for uplink data transmission.

[0219] After receiving the DCI information, the terminal device can determine the precoding matrix W corresponding to each sub-band based on the received K PMIs and the correspondence between sub-bands and precoding matrices in the second message. PMI For each subband, the terminal device can use the precoding matrix W corresponding to that subband. PMI Adjust the weights of the data on the antenna port corresponding to the subband across the four antennas to achieve a beam in a specified direction.

[0220] The network device provides the uplink channel matrix H for each sub-band. ul SVD decomposition can yield H ul =U ul Σ ul V ul * , where Σ ul It is a 64*4 diagonal matrix, U ul and V ul Let Σ be a unitary matrix of 64x64 and 4x4 respectively. ul If the two non-zero elements on the diagonal are the first two elements on the diagonal, then the matrix U corresponding to that subband can be obtained. Matrix U is derived from U ul The matrix consists of the first two columns, with a dimension of 64*2. Based on the matrix U corresponding to each sub-band, the network device can recover the original transmitted data of that sub-band from the signal received at the antenna port corresponding to that sub-band. By performing the above operation on M sub-bands, the network device can obtain the original transmitted data corresponding to the entire bandwidth.

[0221] In one possible implementation, the terminal device uses independent subband precoding based on a non-codebook for uplink data transmission.

[0222] After receiving the DCI information, the terminal device can determine the SRS resource corresponding to each sub-band and the precoding matrix corresponding to that SRS resource based on the SRI, thereby obtaining M precoding matrices corresponding to M sub-bands. For each sub-band, the terminal device can adjust the weights of the data on the antenna port corresponding to that sub-band across the four antennas using the precoding matrix, thus achieving beamforming in a specified direction.

[0223] The network device provides the uplink channel matrix H for each sub-band. ul SVD decomposition yields matrix U. Based on matrix U corresponding to each sub-band, the network device can recover the original transmitted data of that sub-band from the signal received at the antenna port corresponding to that sub-band. By performing the above operation on M sub-bands, the network device can obtain the original transmitted data corresponding to the entire bandwidth.

[0224] As shown in Figure 5, the four sub-bands correspond to four precoding matrices V1, V2, V3, and V4, and each sub-band corresponds to one of the four antenna ports. The terminal device can precode the uplink data of the four sub-bands using precoding matrices V1, V2, V3, and V4 respectively, and then transmit it through the antenna port corresponding to that sub-band.

[0225] S305. The terminal device sends fourth information, which is used to indicate the number of subbands M, the number of precoding matrices K, and the number of antenna ports N.

[0226] After obtaining information that the terminal device supports independent subband precoding, the network device can send first information to the terminal device, instructing the terminal device to use independent subband precoding when performing uplink transmission.

[0227] In one possible implementation, the terminal device sends a fourth message to the network device. This fourth message indicates the number of subbands M, the number of precoding matrices K, and the number of antenna ports N corresponding to each subband. M and K are integers greater than 1, K is less than or equal to M, and N is an integer greater than or equal to 1, where N is less than the number of antenna ports L of the terminal device, and L is an integer greater than 1. Upon receiving the fourth message, the network device, based on the values ​​of M, K, and N, the relationship between M and K, and the relationship between N and L, can determine that the terminal device supports independent subband precoding, and can then send the first message to the terminal device.

[0228] In one possible implementation, the terminal device receives fifth information from the network device, the fifth information including a second field indicating whether the network device expects to obtain a precoding type supported by the terminal device.

[0229] Optionally, the fifth piece of information may be a User Equipment Information Request (UEInformationRequest) message.

[0230] Optionally, the second field may include one bit, the presence of which can be used to indicate whether the network device expects to acquire a precoding type supported by the terminal device.

[0231] For example, the presence of one bit can indicate that the network device expects to obtain a precoding type supported by the terminal device, and the absence of one bit can indicate that the network device does not expect to obtain a precoding type supported by the terminal device.

[0232] For example, the presence of this 1 bit can indicate that the network device does not expect to acquire the precoding type supported by the terminal device, while the absence of this 1 bit can indicate that the network device expects to acquire the precoding type supported by the terminal device.

[0233] It is understood that the embodiments of this application do not limit the mapping relationship between the existence of this 1 bit and whether the network device expects to obtain the precoding type supported by the terminal device.

[0234] Optionally, the second field may include a 1-bit state that can be used to indicate whether the network device expects to acquire a precoding type supported by the terminal device.

[0235] For example, bit "0" can indicate that the network device expects to obtain a precoding type supported by the terminal device, and bit "1" can indicate that the network device does not expect to obtain a precoding type supported by the terminal device.

[0236] For example, bit "0" can indicate that the network device does not expect to obtain the precoding type supported by the terminal device, and bit "1" can indicate that the network device expects to obtain the precoding type supported by the terminal device.

[0237] It is understood that the embodiments of this application do not limit the mapping relationship between the bit state of the 1 bit and whether the network device expects to obtain the precoding type supported by the terminal device.

[0238] It is understood that the second field may also include more bits (e.g., 2 bits, 3 bits, etc.), and this application embodiment does not limit this.

[0239] When the second field indicates that the network device expects to obtain the precoding type supported by the terminal device, the terminal device sends the precoding type supported by the terminal device to the network device.

[0240] In one possible implementation, the terminal device sends fourth information to the network device. This fourth information includes a third field indicating the precoding types supported by the terminal device. The precoding types supported by the terminal device may include full-band precoding and / or sub-band precoding and / or independent sub-band precoding.

[0241] Optionally, the fourth piece of information may be a User Equipment Capability Information (UECapabilityInformation) message.

[0242] Optionally, the third field may include at least 3 bits, which form a bitmap that can be used to indicate the precoding type supported by the terminal device.

[0243] For example, the third field may include 3 bits: bit "001" represents full-band precoding, bit "010" represents sub-band precoding, bit "100" represents independent sub-band precoding, bit "011" represents full-band precoding and sub-band precoding, bit "101" represents full-band precoding and independent sub-band precoding, bit "110" represents sub-band precoding and independent sub-band precoding, and bit "111" represents full-band precoding, sub-band precoding, and independent sub-band precoding.

[0244] It is understood that the third field may also include more bits (e.g., 4 bits, 5 bits, etc.), and this application embodiment does not limit this. Furthermore, this application embodiment does not limit the mapping relationship between a bitmap consisting of at least 3 bits and the precoding types supported by the terminal device.

[0245] Optionally, the third field may include at least 3 bits, the bit status of which may be used to indicate the precoding type supported by the terminal device.

[0246] For example, the third field may include 3 bits: bit "000" represents full-band precoding, bit "001" represents sub-band precoding, bit "010" represents independent sub-band precoding, bit "011" represents full-band precoding and sub-band precoding, bit "100" represents full-band precoding and independent sub-band precoding, bit "101" represents sub-band precoding and independent sub-band precoding, and bit "110" represents full-band precoding, sub-band precoding, and independent sub-band precoding.

[0247] It is understood that the third field may also include more bits (e.g., 4 bits, 5 bits, etc.), and this application embodiment does not limit this. Furthermore, this application embodiment does not limit the mapping relationship between the bit state of at least 3 bits and the precoding types supported by the terminal device.

[0248] After receiving the fourth information, if the fourth information indicates that the terminal device supports at least independent subband precoding, the network device can send the first information to the terminal device, instructing the terminal device to use independent subband precoding for uplink transmission.

[0249] In one possible implementation, the terminal device receives fifth information from the network device, which includes a fourth field indicating whether the network device expects to obtain information on whether the terminal device supports independent subband precoding.

[0250] Optionally, the fifth piece of information may be a User Equipment Information Request (UEInformationRequest) message.

[0251] Optionally, the fourth field may include one bit, the presence of which can be used to indicate whether the network device expects to obtain information on whether the terminal device supports independent subband precoding.

[0252] The mapping relationship between the existence of this 1 bit and whether the network device expects to obtain information on whether the terminal device supports independent subband precoding can be referred to the mapping relationship between the existence of this 1 bit and whether the network device expects to obtain information on the precoding types supported by the terminal device, which will not be repeated here.

[0253] Optionally, the fourth field may include a 1-bit state that can be used to indicate whether the network device expects to obtain information on whether the terminal device supports independent subband precoding.

[0254] The mapping relationship between this 1-bit bit state and whether the network device expects to obtain information on whether the terminal device supports independent subband precoding can be referred to the mapping relationship between the 1-bit bit state and whether the network device expects to obtain information on the precoding types supported by the terminal device described above, and will not be repeated here.

[0255] When the fourth field indicates that the network device expects to obtain information on whether the terminal device supports independent subband precoding, the terminal device sends information to the network device on whether the terminal device supports independent subband precoding.

[0256] In one possible implementation, the terminal device sends a fourth message to the network device, which includes a fifth field indicating whether the terminal device supports independent subband precoding.

[0257] Optionally, the fourth piece of information may be a User Equipment Capability Information (UECapabilityInformation) message.

[0258] Optionally, the fifth field may include one bit, the presence of which can be used to indicate whether the terminal device supports independent subband precoding.

[0259] For example, the presence of this 1 bit can indicate that the terminal device supports independent subband precoding, while the absence of this 1 bit can indicate that the terminal device does not support independent subband precoding.

[0260] For example, the presence of this 1 bit can indicate that the terminal device does not support independent subband precoding, while the absence of this 1 bit can indicate that the terminal device supports independent subband precoding.

[0261] It is understood that the embodiments of this application do not limit the mapping relationship between the existence of this 1 bit and whether the terminal device supports independent subband precoding.

[0262] Optionally, the fifth field may include one bit, the state of which can be used to indicate whether the terminal device supports independent subband precoding.

[0263] For example, bit "0" can indicate that the terminal device supports independent subband precoding, and bit "1" can indicate that the terminal device does not support independent subband precoding.

[0264] For example, bit "0" can indicate that the terminal device does not support independent subband precoding, and bit "1" can indicate that the terminal device supports independent subband precoding.

[0265] It is understood that the embodiments of this application do not limit the mapping relationship between the bit state of the 1 bit and whether the terminal device supports independent subband precoding.

[0266] It is understood that the fifth field may also include more bits (e.g., 2 bits, 3 bits, etc.), and this application embodiment does not limit this.

[0267] After receiving the fourth information, if the fourth information indicates that the terminal device supports independent subband precoding, the network device can send the first information to the terminal device, instructing the terminal device to use independent subband precoding for uplink transmission.

[0268] In the above embodiments, the data of each sub-band is transmitted at part of the antenna port of the terminal device, which can reduce the power back-off of PAPR, which is equivalent to increasing the transmit power of the terminal device, thereby enhancing uplink coverage.

[0269] Understandably, the downlink also suffers from poor performance of wideband precoding and high PAPR of subband precoding. This application also provides another communication method to improve the downlink coverage capability of network devices. This application uses the PDSCH (physical downlink shared channel) signal as an example for illustration. It can be understood that the downlink signals applicable to the communication method provided in this application include, but are not limited to, PDSCH signals, DMRS signals, PDCCH (physical downlink control channel) signals, CSI-RS signals, SSB (synchronization signal block) signals, PTRS signals, etc.

[0270] As shown in Figure 6, Figure 6 is a schematic flowchart of a downlink independent subband precoding method provided in an embodiment of this application. The communication method includes the following steps:

[0271] S601. The network device sends first information, which indicates the number of sub-bands M, the number of precoding matrices K, and the number of antenna ports corresponding to each sub-band N.

[0272] For downlink transmission, network devices can also use independent subband precoding, where M subbands correspond to K precoding matrices, and each subband corresponds to N antenna ports of the network device. Here, M and K are integers greater than 1, K is less than or equal to M, N is an integer greater than or equal to 1, and N is less than the number of antenna ports of the network device P, where P is an integer greater than 1.

[0273] In one possible implementation, the first information indicates the number of subbands M, the number of precoding matrices K, and the number of antenna ports N corresponding to each subband, where M and K are integers greater than 1, K is less than or equal to M, N is an integer greater than or equal to 1, and N is less than P. After receiving the first information, the terminal device can determine, based on the values ​​of M, K, and N, the relationship between M and K, and the relationship between N and P, that the network device uses independent subband precoding for downlink transmission.

[0274] In one possible implementation, the first information is used to indicate that the network device uses independent subband precoding when transmitting downlink data. The precoding types include full-band precoding, subband precoding, and independent subband precoding. The method for indicating independent subband precoding can be found in the description in S301, and will not be repeated here.

[0275] S602. The network device sends second information, which indicates the correspondence between M subbands and K precoding matrices, and the correspondence between each subband and N antenna ports.

[0276] The network device can send second information to the terminal device. After receiving the second information, the terminal device can determine the correspondence between the M subbands and K precoding matrices, as well as the correspondence between each subband and N antenna ports when the network device is performing downlink transmission. Then, it can receive downlink data according to the above correspondence.

[0277] To determine the frequency domain location and bandwidth of the M sub-bands, network devices can also send sub-band configuration information to terminal devices.

[0278] The representation of the above correspondence and the sub-band configuration information can be found in the description in S302, and will not be repeated here.

[0279] S603. Network devices send downlink data.

[0280] Network devices can precode downlink data based on the second information and the downlink precoding matrix before sending it to the terminal device.

[0281] Assume the network devices have 64 antennas and the terminal devices have 4 antennas, i.e., m = 64 and n = 4. Also assume the downlink channel matrix H... dl The rank is 2, meaning that the network device can transmit a maximum of two streams of data.

[0282] In one possible implementation, the network device employs codebook-based downlink independent subband precoding, the process of which is shown in Figure 7A, including:

[0283] 1. Network devices send CSI-RS signals to terminal devices.

[0284] Assuming the CSI-RS has 32 ports, and since the network device has 64 antennas, the network device can use a weight matrix W with dimensions 64*32. CSI-RS The CSI-RS signal on port 32 is mapped onto 64 antennas and transmitted to the terminal device. This weight matrix W CSI- RS It can be called the CSI-RS weight matrix.

[0285] 2. The terminal device selects K PMIs from the codebook defined by the protocol based on the measurement results of the CSI-RS signal.

[0286] Since the terminal device can identify up to 32 CSI-RS ports, it can obtain the downlink channel matrix H by measuring the CSI-RS signals. dl H dlThe dimension is 4*32, where 32 is the number of CSI-RS ports and 4 is the number of receiving antennas of the terminal device.

[0287] For each sub-band, the terminal device has the corresponding channel matrix H. dl SVD decomposition can yield H dl =U dl Σ dl V dl * , where Σ dl It is a 4*32 diagonal matrix, U dl and V dl These are unitary matrices of 4x4 and 32x32 respectively. Since the downlink channel matrix H... dl The rank of Σ is 2, i.e., Σ dl If there are two non-zero elements on the diagonal, the terminal device can determine that the appropriate downlink transmission layer number for the current channel is 2. Assume Σ dl If the two non-zero elements on the diagonal are the first two elements on the diagonal, then the precoding matrix W corresponding to that subband can be obtained. PM W PM By V dl The first two columns of elements form the matrix, with a dimension of 32*2. Performing the above operation on M subbands yields M precoding matrices W. PM .

[0288] Assuming the protocol defines G codebooks, the terminal device can use M precoding matrices W. PM Select K suitable codebooks W from the G codebooks defined in the protocol. PMI The K codebooks W PMI It can be indicated by K PMIs, where K is less than or equal to G. Since multiple precoding matrices W may exist... PM Corresponding to the same codebook W PMI Therefore, K is less than or equal to M.

[0289] 3. The terminal device reports CSI and sends K PMIs to the network device.

[0290] The terminal device reports a CSI to the network device. This CSI may include K PMIs, which instruct the terminal device to select K codebooks W from the G codebooks defined by the 3GPP protocol. PMI .

[0291] 4. Network devices use codebooks corresponding to K PMIs to precode downlink transmissions.

[0292] Based on the received K PMIs and the correspondence between subbands and precoding matrices in the second message, the network device can determine the precoding matrix corresponding to each subband. For each subband, the network device can determine the precoding matrix W corresponding to that subband. PMI The data from the antenna ports corresponding to this sub-band is weighted. Since the network device has 64 antennas, the data from the antenna ports corresponding to this sub-band is weighted using the PMI weight matrix W. PMI After weighting, the same mapping method as mapping CSI-RS signals to 64 antennas can be used, that is, using the CSI-RS weight matrix W. CSI-RS A second weighting is performed to adjust the weights of the data at the antenna port corresponding to this sub-band across the 64 antennas, thereby achieving beamforming in the specified direction. Therefore, the CSI-RS weight matrix W... CSI-RS With PMI weight matrix W PMI The result of multiplication W CSI- RS *W PMI That is the final precoding scheme.

[0293] In one possible implementation, the terminal device assigns a downlink channel matrix H to each subband. dl SVD decomposition can yield H dl =U dl Σ dl V dl * , where Σ dl It is a 4*32 diagonal matrix, U dl and V dl Let Σ be a unitary matrix of 4x4 and 32x32 respectively. dl If the two non-zero elements on the diagonal are the first two elements on the diagonal, then the matrix U corresponding to that subband can be obtained. Matrix U is derived from U dl The matrix consists of the first two columns, with a dimension of 4*2. Based on the matrix U corresponding to each sub-band, the terminal device can recover the original transmitted data of that sub-band from the signal received at the antenna port corresponding to that sub-band. By performing the above operation on M sub-bands, the terminal device can obtain the original transmitted data corresponding to the entire bandwidth.

[0294] In one possible implementation, the network device employs downlink independent subband precoding based on a non-codebook, as shown in Figure 7B, including:

[0295] 1. The terminal device sends an SRS signal to the network device.

[0296] Optionally, the terminal device can transmit SRS signals using an antenna rotation method. For example, the terminal device can transmit SRS signals on four antennas in turn, selecting one antenna to transmit at a time; or, for another example, the terminal device can transmit SRS signals on four antennas in turn, selecting two antennas to transmit at a time.

[0297] Optionally, the terminal device can transmit SRS signals in a non-antenna round-robin manner. For example, the terminal device can transmit SRS signals to the network device by fixing one antenna; or, for another example, the terminal device can transmit SRS signals to the network device by fixing two antennas.

[0298] 2. Based on the measurement results of the SRS signal, the network device calculates the downlink precoding matrix using the reciprocity of the uplink and downlink channels.

[0299] Assuming the terminal device transmits SRS signals using an antenna-round-robin method, the network device can obtain the uplink channel matrix H corresponding to each subband after measuring the SRS signal. ul H ul The dimension is 64*4. Network devices, based on the reciprocity of uplink and downlink channels, adjust the uplink channel matrix H... ul By performing a transpose operation, we can obtain a 4*64 downlink channel matrix H. dl .

[0300] For each subband, the corresponding downlink channel matrix H dl SVD decomposition can yield H dl =U dl Σ dl V dl * , where Σ dl It is a 4*64 diagonal matrix, U dl and V dl The downlink channel matrix H consists of 4x4 and 64x64 unitary matrices respectively. dl The rank of Σ is 2, i.e., Σ dl There are two non-zero elements on the diagonal, meaning that when a network device transmits two streams of data, its layer mapping will map to two PDSCH ports. Assume Σ dl If the two non-zero elements on the diagonal are the first two elements on the diagonal, then the precoding matrix W corresponding to that subband can be obtained. PM W PM By V dl The first two columns of elements form the matrix, with a dimension of 64*2. Performing the above operation on M subbands yields M precoding matrices W. PM For non-codebook-based downlink independent subband precoding, K equals M.

[0301] It should be noted that the above method also applies to situations where the terminal device transmits SRS signals using a non-antenna round-robin method, which will not be elaborated upon here.

[0302] 3. Network devices use this precoding matrix to precode downlink transmissions.

[0303] For each subband, the network device uses the precoding matrix W corresponding to that subband. PM The weights of the data on the antenna port corresponding to this subband are adjusted across the 64 antennas to achieve a beam in the specified direction.

[0304] In one possible implementation, similar to codebook-based downlink precoding, the terminal device precodes the downlink channel matrix H corresponding to each subband. dl SVD decomposition yields matrix U. Based on matrix U corresponding to each sub-band, the terminal device can recover the original transmitted data of that sub-band from the signal received at the antenna port corresponding to that sub-band. By performing the above operation on M sub-bands, the terminal device can obtain the original transmitted data corresponding to the entire bandwidth.

[0305] As shown in Figure 5, the four sub-bands correspond to four precoding matrices V1, V2, V3, and V4, and each sub-band corresponds to one of the four antenna ports. The network device can precode the uplink data of the four sub-bands using precoding matrices V1, V2, V3, and V4 respectively, and then transmit it through the antenna port corresponding to that sub-band.

[0306] S604. The terminal device sends fourth information, which is used to indicate the number of sub-bands M, the number of precoding matrices K, and the number of antenna ports N.

[0307] After obtaining information that the terminal device supports independent subband precoding, the network device can send first information to the terminal device, instructing the network device to use independent subband precoding when performing downlink transmission.

[0308] In one possible implementation, the terminal device sends a fourth message to the network device. This fourth message indicates the number of subbands M, the number of precoding matrices K, and the number of antenna ports N corresponding to each subband. M and K are integers greater than 1, K is less than or equal to M, and N is an integer greater than or equal to 1, and N is less than the number of antenna ports P of the network device, where P is an integer greater than 1. Upon receiving the fourth message, the network device, based on the values ​​of M, K, and N, the relationship between M and K, and the relationship between N and P, can determine that the terminal device supports independent subband precoding, and can then send the first message to the terminal device.

[0309] In one possible implementation, the terminal device receives fifth information sent by the network device. The fifth information is used to indicate whether the network device expects to obtain the precoding type supported by the terminal device. Refer to the description in S305, which will not be repeated here.

[0310] When the fifth message indicates that the network device expects to obtain the precoding type supported by the terminal device, the terminal device sends the precoding type supported by the terminal device to the network device.

[0311] In one possible implementation, the terminal device sends a fourth message to the network device. The fourth message indicates the precoding type supported by the terminal device, which can be referred to in the description in S305, and will not be repeated here.

[0312] After receiving the fourth information, if the fourth information indicates that the terminal device supports at least independent subband precoding, the network device can send the first information to the terminal device, instructing the network device to use independent subband precoding when performing downlink transmission.

[0313] In one possible implementation, the terminal device receives fifth information sent by the network device. The fifth information is used to indicate whether the network device expects to obtain information on whether the terminal device supports independent subband precoding. This can be referred to in the description in S305, and will not be repeated here.

[0314] When the fifth message indicates that the network device expects to obtain information on whether the terminal device supports independent subband precoding, the terminal device sends information to the network device on whether the terminal device supports independent subband precoding.

[0315] In one possible implementation, the terminal device sends a fourth message to the network device. The fourth message indicates whether the terminal device supports independent subband precoding, as described in S305, and will not be repeated here.

[0316] After receiving the fourth information, if the fourth information indicates that the terminal device supports independent subband precoding, the network device can send the first information to the terminal device, instructing the network device to use independent subband precoding when performing downlink transmission.

[0317] In the above embodiments, data for each subband is transmitted at some antenna ports of the network device, which reduces PAPR power back-off, effectively increasing the transmit power of the network device and thus enhancing downlink coverage.

[0318] It should be noted that some steps in the above embodiments are not essential; that is, some steps are optional and can be omitted or replaced by other steps. Furthermore, the above embodiments do not limit the execution order of the method steps. In addition, this application describes the embodiments using terminal devices and network devices as examples of execution subjects. It can be understood that the method executed by the terminal device can also be executed by components suitable for the terminal device (e.g., chips, circuits, etc.), and the method executed by the network device can also be executed by components suitable for the network device (e.g., chips, circuits, etc.).

[0319] To achieve the functions of the methods provided in the embodiments of this application, both the terminal device and the network device may include hardware structures and / or software modules, implementing the above functions in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Whether a particular function is executed in the form of hardware structures, software modules, or a combination of hardware structures and software modules depends on the specific application and design constraints of the technical solution.

[0320] Please refer to Figure 8, which shows a schematic diagram of a communication device according to an embodiment of this application. The communication device can be a terminal device or a network device, or a device compatible with a terminal device or a network device, or it can also be a chip system. In one possible implementation, the communication device may include modules or units corresponding to the methods / operations / steps / actions performed by the communication device in the method embodiments shown in Figure 3 or Figure 6. These units can be hardware circuits, software, or a combination of hardware circuits and software.

[0321] The communication device shown in Figure 8 may include a processing unit 801 and a communication unit 802. The processing unit 801 is used for data processing. The communication unit 802 integrates a receiving unit and a transmitting unit. The communication unit 802 may also be referred to as a transceiver unit. Alternatively, the communication unit 802 may be split into a receiving unit and a transmitting unit.

[0322] When the communication device is used to perform some or all of the functions in the method embodiment described in FIG3 above, the communication unit 802 is used for the network device to send first information, second information and third information to the terminal device, and for the terminal device to send uplink data and fourth information to the network device; the processing unit 801 is used for the network device to determine K precoding matrices; the communication unit 802 is also used for the terminal device to receive the first information, second information and third information sent by the network device, and for the network device to receive the uplink data and fourth information sent by the terminal device; the communication unit 802 is also used for the terminal device to precode the uplink data of each subband.

[0323] When the communication device is used to perform some or all of the functions in the method embodiment described in FIG6 above, the communication unit 802 is used for the network device to send first information, second information and downlink data to the terminal device, and for the terminal device to send fourth information to the network device; the processing unit 801 is used for the terminal device or the network device to determine K precoding matrices; the communication unit 802 is also used for the terminal device to receive the first information, second information and downlink data sent by the network device, and for the network device to receive the fourth information sent by the terminal device; the communication unit 802 is also used for the network device to precode the downlink data of each subband.

[0324] Figure 9 shows a schematic diagram of another communication device. The communication device 900 can be the communication device in the above method embodiments, or it can be a chip, chip system, or processor that supports the communication device in implementing the above methods. This communication device 900 can be used to implement the methods described in the above method embodiments; for details, please refer to the descriptions in the above method embodiments.

[0325] The communication device 900 may include one or more processors 901. The processor 901 may be a general-purpose processor or a dedicated processor, such as a baseband processor or a central processing unit (CPU). The baseband processor can be used to process communication protocols and communication data, while the CPU can be used to control the communication device (e.g., base station, baseband chip, terminal, terminal chip, DU or CU, etc.), execute software programs, and process data from the software programs.

[0326] Optionally, the communication device 900 may include one or more memories 902, which may store instructions 904. These instructions can be executed on the processor 901, causing the communication device 900 to perform the methods described in the above method embodiments. Optionally, the memory 902 may also store data. The processor 901 and the memory 902 may be provided separately or integrated together.

[0327] Optionally, the communication device 900 may further include a transceiver 905 and an antenna 906. The transceiver 905 may be referred to as a transceiver unit, transceiver, or transceiver circuit, etc., and is used to implement the transmission and reception functions. The transceiver 905 may include a receiver and a transmitter. The receiver may be referred to as a receiver or receiving circuit, etc., and is used to implement the receiving function; the transmitter may be referred to as a transmitter or transmitting circuit, etc., and is used to implement the transmitting function.

[0328] The processor 901 is used to perform the data processing operation of the communication device in the above method embodiment, and the transceiver 905 is used to perform the data transmission and reception operation of the communication device in the above method embodiment.

[0329] In another possible design, the processor 901 may include a transceiver for implementing receive and transmit functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing receive and transmit functions may be separate or integrated. The aforementioned transceiver circuit, interface, or interface circuit may be used for reading and writing code / data, or for transmitting or relaying signals.

[0330] In another possible design, the processor 901 may optionally store instructions 903, which, when executed on the processor 901, cause the communication device 900 to perform the methods described in the above method embodiments. Instructions 903 may be embedded in the processor 901; in this case, the processor 901 may be implemented in hardware.

[0331] In another possible design, the communication device 900 may include circuitry that performs the functions of sending, receiving, or communicating as described in the foregoing method embodiments. The processors and transceivers described in this application can be implemented on integrated circuits (ICs), analog ICs, radio frequency integrated circuits (RFICs), mixed-signal ICs, application-specific integrated circuits (ASICs), printed circuit boards (PCBs), electronic devices, etc.

[0332] The communication device described in the above embodiments can be a transmitting end or a receiving end, but the scope of the communication device described in the embodiments of this application is not limited thereto, and the structure of the communication device is not limited to FIG9. The communication device can be a standalone device or can be part of a larger device. For example, the communication device can be:

[0333] (1) Independent integrated circuit IC, or chip, or chip system or subsystem;

[0334] (2) A collection of one or more ICs, optionally including a storage component for storing data and instructions;

[0335] (3) ASIC, such as modem (mobile station modem, MSM);

[0336] (4) Modules that can be embedded in other devices;

[0337] (5) Receivers, terminals, smart terminals, cellular phones, wireless devices, handheld devices, mobile units, vehicle-mounted devices, cloud devices, artificial intelligence devices, etc.

[0338] (6) Others, etc.

[0339] For communication devices that can be chips or chip systems, please refer to the schematic diagram of the chip structure shown in Figure 10. The chip shown in Figure 10 includes a processor 1001 and an interface 1002. Optionally, it may also include a memory 1003. The number of processors 1001 can be one or more, and the number of interfaces 1002 can be multiple.

[0340] In one design, for a chip used to implement the function of the communication device in the embodiments of this application: the interface 1002 is used to input or output signals; the processor 1001 is used to execute the data processing operation of the communication device in the above method embodiments.

[0341] It is understood that some optional features in the embodiments of this application can be implemented independently in certain scenarios without relying on other features, such as the current solution on which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Correspondingly, the communication device given in the embodiments of this application can also implement these features or functions, which will not be elaborated here.

[0342] It should be understood that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the above method embodiments can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor described above can be a general-purpose processor, a digital signal processor (DSP), an ASIC, a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0343] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0344] This application also provides a computer-readable medium for storing computer software instructions that, when executed by a communication device, implement the functions of any of the above method embodiments.

[0345] This application also provides a computer program product for storing computer software instructions, which, when executed by a communication device, implement the functions of any of the above method embodiments.

[0346] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state drives (SSDs)).

[0347] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

Claims

1. A communication method, characterized in that, The method includes: Receive first information from a network device, the first information being used to indicate the number of subbands M and the number of precoding matrices K, and the number of antenna ports N corresponding to each subband, wherein M and K are integers greater than 1, K is less than or equal to M, and N is an integer greater than or equal to 1; When data is sent to the network device, N is less than the number of antenna ports L of the terminal device, where L is an integer greater than 1; When receiving data from the network device, N is less than the number of antenna ports P of the network device, where P is an integer greater than 1.

2. The method according to claim 1, characterized in that, The method further includes: The system receives second information from the network device, the second information indicating the correspondence between the M subbands and the K precoding matrices, and the correspondence between each subband and the N antenna ports.

3. The method according to claim 2, characterized in that, The method further includes: Receive third information from the network device, the third information being used to indicate the K precoding matrices; Based on the second information and the third information, data is sent to the network device.

4. The method according to claim 2 or 3, characterized in that, The method further includes: Based on the second information, data is received from the network device.

5. The method according to any one of claims 1 to 4, characterized in that, The method further includes: A fourth message is sent to the network device, the fourth message indicating the number of subbands M, the number of precoding matrices K, and the number of antenna ports corresponding to each subband N.

6. A communication method, characterized in that, The method includes: Send first information to the terminal device. The first information is used to indicate the number of sub-bands M and the number of precoding matrices K, as well as the number of antenna ports N corresponding to each sub-band. M and K are integers greater than 1, K is less than or equal to M, and N is an integer greater than or equal to 1. When receiving data from the terminal device, N is less than the number of antenna ports L of the terminal device, where L is an integer greater than 1; When data is sent to the terminal device, N is less than the number of antenna ports P of the network device, where P is an integer greater than 1.

7. The method according to claim 6, characterized in that, The method further includes: The terminal device is also sent a second message, which indicates the correspondence between the M subbands and the K precoding matrices, as well as the correspondence between each subband and the N antenna ports.

8. The method according to claim 7, characterized in that, The method further includes: Send third information to the terminal device, the third information being used to indicate the K precoding matrices; Based on the second information and the third information, data is received from the terminal device.

9. The method according to claim 7, characterized in that, The method further includes: Based on the second information, data is sent to the terminal device.

10. The method according to any one of claims 6 to 9, characterized in that, The method further includes: The terminal device receives fourth information, which indicates the number of subbands M, the number of precoding matrices K, and the number of antenna ports corresponding to each subband N.

11. A communication device, characterized in that, The device includes a processor coupled to a memory for storing instructions that, when executed by the processor, cause the communication device to perform the method of any one of claims 1 to 5, or cause the communication device to perform the method of any one of claims 6 to 10.

12. A computer-readable storage medium having instructions stored thereon, characterized in that, When the instructions are executed, they cause the computer to perform the method of any one of claims 1 to 5, or cause the computer to perform the method of any one of claims 6 to 10.

13. A computer program product, the computer program product comprising instructions, characterized in that, When the instructions are executed, they cause the computer to perform the method of any one of claims 1 to 5, or cause the computer to perform the method of any one of claims 6 to 10.

14. A chip, characterized in that, The chip includes a processor and a communication interface, the communication interface being used to communicate with external or internal devices, and the processor being used to implement the method of any one of claims 1 to 5, or to implement the method of any one of claims 6 to 10.

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