Communication method and communication apparatus

Abstract

The present application provides a communication method and a communication apparatus. The communication method comprises: receiving a reference signal, the reference signal being used for determining CSI; and sending first CSI, the first CSI comprising first information and at least two of the following pieces of CSI: information used for indicating first channel quality, information used for indicating second channel quality, and second information. The first channel quality corresponds to a first precoding matrix, and the second channel quality corresponds to a second precoding matrix. The second information indicates a deviation between the first channel quality and the second channel quality, and the first information is used for indicating a target flow corresponding to the first channel quality and a target flow corresponding to the second channel quality. The communication method can improve the reception performance of a terminal when the terminal does not report a PMI.

Description

Communication methods and communication devices

[0001] This application claims priority to Chinese Patent Application No. 202411573700.X, filed on November 5, 2024, entitled "Communication Method and Communication Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communications, and more particularly to a communication method and a communication device. Background Technology

[0003] In order to improve downlink communication quality, when a network device sends data to a terminal, it can process the data to be sent using a precoding matrix that matches the channel. This ensures that the data to be sent is adapted to the channel after processing by the precoding matrix, thereby preventing interference between the data of each parallel stream during terminal demodulation.

[0004] In one implementation, the network device can determine the precoding matrix that matches the channel by using the precoding matrix index (PMI) reported by the terminal.

[0005] However, terminal feedback of PMIs leads to significant overhead for the terminal. Therefore, how to improve the reception performance of the terminal without it reporting PMIs has become an urgent technical problem to be solved. Summary of the Invention

[0006] This application provides a communication method and a communication device, which can improve the receiving performance of a terminal without the terminal reporting PMI.

[0007] Firstly, embodiments of this application provide a communication method that can be applied to a communication device on the terminal side, such as a terminal or a communication module within a terminal, or a circuit or chip (such as a modem chip, also known as a baseband chip, or a system-on-chip (SoC) chip containing a modem core, or a system-in-package (SIP) chip) responsible for communication functions within the terminal. In this application, a terminal is used as an example for description.

[0008] The communication method includes: receiving a reference signal, the reference signal being used to determine channel state information (CSI); transmitting a first CSI, the first CSI including first information and at least two of the following CSIs: information indicating a first channel quality, information indicating a second channel quality, and second information, wherein the first channel quality corresponds to a first precoding matrix, the second channel quality corresponds to a second precoding matrix, the second information indicates the deviation between the first channel quality and the second channel quality, and the first information is used to indicate the target stream corresponding to the first channel quality and the target stream corresponding to the second channel quality.

[0009] For example, information used to indicate channel quality is called a channel quality indicator (CQI). Correspondingly, information used to indicate the quality of a first channel can be called a first CQI, and information used to indicate the quality of a second channel can be called a second CQI.

[0010] For example, the reference signal received by the terminal is the channel state information reference signal (CSI-RS).

[0011] In this technical solution, after receiving the reference signal sent by the network device, the terminal determines the first channel quality corresponding to the first precoding matrix and the second channel quality corresponding to the second precoding matrix based on the measurement of the reference signal. Then, it indicates the first channel quality corresponding to the first precoding matrix and the second channel quality corresponding to the second precoding matrix to the network device. For example, the first precoding matrix is ​​determined based on the conjugate transpose of the downlink channel matrix, and the second precoding matrix is ​​determined based on the right singular matrix obtained after performing singular value decomposition (SVD) on the downlink channel matrix.

[0012] Based on the technical solution provided in the first aspect above, since the terminal indicates the target flow corresponding to the first channel quality and the target flow corresponding to the second channel quality to the network device, the network device can determine the first precoding matrix and the second precoding matrix based on the target flow corresponding to the first channel quality and the target flow corresponding to the second channel quality, respectively. Then, based on the deviation between the first channel quality corresponding to the first precoding matrix and the second channel quality corresponding to the second precoding matrix, the network device determines the precoding matrix to be used when sending downlink data to the terminal, thereby improving the terminal's receiving performance. For example, the network device determines the downlink channel matrix based on the channel reciprocity of the uplink and downlink channels, then determines the first precoding matrix based on the downlink channel matrix and the target flow corresponding to the first channel quality, and determines the second precoding matrix based on the downlink channel matrix and the target flow corresponding to the second channel quality.

[0013] On the other hand, if the first precoding matrix is ​​determined based on the conjugate transpose of the downlink channel matrix and the network device determines to use the first precoding matrix to process the downlink data sent to the terminal, then the network device can also adjust some other parameters based on the deviation between the first channel quality corresponding to the first precoding matrix and the second channel quality corresponding to the second precoding matrix. For example, it can adjust the modulation and coding scheme (MCS) based on the difference between the first CQI and the second CQI, thus improving the receiving performance of the terminal.

[0014] From another perspective, it is understandable that, based on the technical solution provided in the first aspect above, even if the terminal does not report the PMI, the network device can still determine the precoding matrix used when sending downlink data. Therefore, the high power consumption caused by the terminal reporting the PMI can be reduced. Furthermore, the network device no longer needs to send precoded reference signals to the terminal to determine the target flow, thus also helping to reduce the overhead of the network device sending reference signals.

[0015] In conjunction with the first aspect, in one possible implementation, the above method further includes: receiving third information, which indicates whether to report CSI based on the first CSI.

[0016] In this application, the uplink control information (UCI) carrying the first CSI is also referred to as the first UCI. Correspondingly, the third information used to indicate whether the terminal reports CSI based on the first CSI can also be replaced with: the third information used to indicate whether the terminal reports CSI based on the first UCI.

[0017] Understandably, in this implementation, if the network device instructs the terminal to report the CSI based on the first UCI, the terminal then sends the aforementioned first CSI based on the first UCI.

[0018] In conjunction with the first aspect, in one possible implementation, the above method further includes: sending first capability information, which indicates the capability to support reporting CSI based on the first CSI.

[0019] Understandably, the first capability information used to indicate the capability to support CSI reporting based on the first CSI can also be replaced with: the first capability information used to indicate the capability to support CSI reporting based on the first UCI.

[0020] In conjunction with the first aspect, in one possible implementation, the first CSI also includes fourth information, which indicates a recommended precoding matrix, which is either the first precoding matrix or the second precoding matrix.

[0021] Secondly, embodiments of this application provide a communication method that can be applied to a network-side communication device, such as a network device, a module (e.g., a circuit, chip, or chip system) within the network device, or a logic node, logic module, or software capable of implementing all or part of the functions of the network device. Taking the application of this method to a network device as an example...

[0022] The communication method includes: transmitting a reference signal for determining channel state information (CSI); receiving a first CSI from a terminal, the first CSI including first information and at least two of the following CSIs: information indicating a first channel quality, information indicating a second channel quality, and second information, wherein the first channel quality corresponds to a first precoding matrix, the second channel quality corresponds to a second precoding matrix, the first information indicates the deviation between the first channel quality and the second channel quality, and the first information is used to indicate the target stream corresponding to the first channel quality and the target stream corresponding to the second channel quality; and transmitting downlink data based on the first CSI.

[0023] For example, transmitting downlink data based on the first CSI includes: determining the transmission method of the downlink data based on the first CSI; and transmitting the downlink data based on the transmission method.

[0024] For example, the method of transmitting downlink data is determined based on the first CSI, such as whether to precode the downlink data using a first precoding matrix or a second precoding matrix.

[0025] Based on the technical solution provided in the second aspect above, since the terminal indicates the target flow corresponding to the first channel quality and the target flow corresponding to the second channel quality to the network device, the network device can determine the first precoding matrix and the second precoding matrix based on the target flow corresponding to the first channel quality and the target flow corresponding to the second channel quality, respectively. Then, based on the deviation between the first channel quality corresponding to the first precoding matrix and the second channel quality corresponding to the second precoding matrix, the network device determines the precoding matrix to be used when sending downlink data to the terminal, thereby improving the terminal's receiving performance. For example, the network device determines the downlink channel matrix based on the channel reciprocity of the uplink and downlink channels, then determines the first precoding matrix based on the downlink channel matrix and the target flow corresponding to the first channel quality, and determines the second precoding matrix based on the downlink channel matrix and the target flow corresponding to the second channel quality.

[0026] On the other hand, if the first precoding matrix is ​​determined based on the conjugate transpose of the downlink channel matrix and the network device uses the first precoding matrix to process the data sent to the terminal, then the network device can also adjust some other parameters based on this deviation, such as adjusting the modulation and coding scheme (MCS) based on the difference between the first CQI and the second CQI, thus improving the receiving performance of the terminal.

[0027] In conjunction with the second aspect, in one possible implementation, the first precoding matrix is ​​determined based on the conjugate transpose of the downlink channel matrix, and the second precoding matrix is ​​determined based on the right singular matrix obtained by SVD of the downlink channel matrix.

[0028] In conjunction with the second aspect, in one possible implementation, transmitting downlink data based on the first CSI includes: transmitting the downlink data based on the first precoding matrix and the target MCS; wherein the target MCS is related to the deviation.

[0029] In conjunction with the second aspect, in one possible implementation, the method further includes: sending third information, which indicates whether to report CSI based on the first CSI.

[0030] In conjunction with the second aspect, in one possible implementation, the method further includes: receiving first capability information, the first capability information being used to indicate the capability to support reporting CSI based on the first CSI.

[0031] In conjunction with the second aspect, in one possible implementation, the first CSI further includes fourth information, which is used to indicate a recommended precoding matrix, which is either the first precoding matrix or the second precoding matrix.

[0032] In conjunction with the second aspect, in one possible implementation, the reference signal is CSI-RS.

[0033] Thirdly, embodiments of this application provide a communication method that can be applied to a communication device on the terminal side, such as a terminal or a communication module in a terminal, or a circuit or chip in the terminal responsible for communication functions (such as a modem chip, also known as a baseband chip, or a system-on-chip (SoC) chip containing a modem core, or a system-in-package (SIP) chip). In this application, a terminal is used as an example for description.

[0034] The communication method includes: receiving fifth information, which instructs the terminal to report a second CSI, the second CSI including PMI and CQI; and sending a third CSI, which includes a first indication information, a second indication information and CQI, the first indication information being used to instruct the PMI to be discarded, and the second indication information being used to instruct the network device to use the target flow when determining the CQI.

[0035] The first instruction message is used to indicate that the PMI should be discarded, which can also be understood as indicating that the PMI should not be reported.

[0036] In this technical solution, the terminal does not report the PMI to the network device, but it indicates the target flow used to determine the CQI. Therefore, the network device can obtain the precoding matrix corresponding to the target flow based on the reciprocity of the uplink and downlink channels and the target flow indicated by the terminal. This allows the network device to send data to the terminal based on the precoding matrix corresponding to the target flow, thus ensuring the terminal's reception performance. On the other hand, it is understandable that this technical solution reduces terminal reporting overhead because the terminal does not report the PMI.

[0037] In conjunction with the third aspect, in one possible implementation, sending a third CSI includes: if it is determined that the conditions for channel stability are met, sending a third CSI.

[0038] For example, the conditions for channel stability include one or more of the following: RSRP is greater than a first threshold, the terminal's moving speed is less than or equal to a second threshold, and the deviation between the predicted channel quality and the actual channel quality is less than a third threshold.

[0039] For example, a terminal can predict channel quality using one or more of the following algorithms: artificial intelligence (AI) algorithms, machine learning (ML) algorithms, and mathematical statistics algorithms.

[0040] For example, channel quality can be measured based on reference signal receiving power (RSRP), channel matrix, and signal to interference plus noise ratio (SINR).

[0041] In conjunction with the third aspect, in one possible implementation, the method further includes: receiving sixth information, which indicates whether to report CSI based on the third CSI.

[0042] The UCI carrying the second CSI is also referred to as the second UCI. The UCI carrying the third CSI is also referred to as the third UCI. Correspondingly, the sixth information is used to indicate whether CSI is reported based on the third CSI, which can also be replaced by: the third information is used to indicate whether CSI is reported based on the third UCI.

[0043] Understandably, in this implementation, if the network device instructs the terminal to report the CSI based on the third UCI, the terminal will then send the aforementioned third CSI based on the third UCI.

[0044] In conjunction with the third aspect, in one possible implementation, the above method further includes: sending second capability information, which indicates the capability to support CSI reporting based on the third CSI.

[0045] Understandably, the second capability information used to indicate the capability to support CSI reporting based on the third CSI can also be replaced with: the second capability information used to indicate the capability to support CSI reporting based on the third UCI.

[0046] In conjunction with the third aspect, in one possible implementation, the method further includes: if it is determined that the channel stability condition is not met, sending the second CSI.

[0047] That is, if it is determined that the channel stability conditions are not met, the terminal sends a second UCI to the network device. The second UCI carries a second CSI. Correspondingly, the network device determines the precoding matrix based on the PMI in the second CSI, and then sends downlink data.

[0048] Fourthly, embodiments of this application provide a communication method that can be applied to a network-side communication device, such as a network device, a module (e.g., a circuit, chip, or chip system) within the network device, or a logical node, logical module, or software capable of implementing all or part of the functions of the network device. Taking the application of this method to a network device as an example...

[0049] The communication method includes: sending fifth information, which instructs the terminal to report a second CSI, the second CSI including PMI and CQI; receiving a third CSI, the third CSI including first indication information, second indication information and CQI, the first indication information instructing the PMI to be discarded, the second indication information instructing the network device to use the target flow when determining the CQI; and sending downlink data based on the third CSI.

[0050] In conjunction with the fourth aspect, in one possible implementation, the above method further includes: sending a sixth message, which indicates whether to report CSI based on the third CSI.

[0051] In conjunction with the fourth aspect, in one possible implementation, the above method further includes: receiving second capability information, which indicates the capability to support CSI reporting based on the third CSI.

[0052] In conjunction with the fourth aspect, in one possible implementation, the method further includes: receiving a second CSI.

[0053] Fifthly, this application provides a communication device that has the functions of the first aspect described above. For example, the communication device includes modules, units, or means that perform the operations involved in the first aspect. These modules, units, or means can be implemented by software, hardware, or a combination of software and hardware.

[0054] In a sixth aspect, this application provides a communication device that has the functions of the second aspect described above. For example, the communication device includes modules, units, or means that perform the operations involved in the second aspect described above. These modules, units, or means can be implemented by software, hardware, or a combination of software and hardware.

[0055] In a seventh aspect, this application provides a communication device that has the functions of the third aspect described above. For example, the communication device includes modules, units, or means that perform the operations involved in the third aspect. These modules, units, or means can be implemented by software, hardware, or a combination of software and hardware.

[0056] Eighthly, this application provides a communication device that has the functions of the fourth aspect above. For example, the communication device includes modules, units, or means that perform the operations involved in the fourth aspect above. These modules, units, or means can be implemented by software, hardware, or a combination of software and hardware.

[0057] Ninthly, this application provides a communication device including an interface circuit and one or more processors. The one or more processors are coupled to a memory. The memory stores part or all of the computer program or instructions necessary to implement the functions described in the first aspect above. The one or more processors are executable to carry out the computer program or instructions, causing the communication device to implement the methods in any possible design or implementation of the first aspect above. The interface circuit is used to implement the communication functions within the communication device and / or the communication functions between the communication device and other devices or components.

[0058] In one possible design, the processor is used to communicate with other devices or components through the interface circuit.

[0059] In one possible design, the communication device may also include the memory.

[0060] For example, the communication device can be a terminal, or a communication module in the terminal, or a chip in the 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.

[0061] Tenthly, this application provides a communication device including an interface circuit and one or more processors. The one or more processors are coupled to a memory. The memory stores part or all of the necessary computer program or instructions for implementing the functions described in the second aspect above. The one or more processors are executable to carry out the computer program or instructions, causing the communication device to implement the methods in any possible design or implementation of the second aspect above. The interface circuit is used to implement the communication functions within the communication device and / or the communication functions between the communication device and other devices or components.

[0062] In one possible design, the processor is used to communicate with other devices or components through the interface circuit.

[0063] In one possible design, the communication device may also include the memory.

[0064] For example, the communication device can be a network device, or a communication module in a network device, or a chip in a network device 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.

[0065] Eleventhly, this application provides a communication device including an interface circuit and one or more processors. The one or more processors are coupled to a memory. The memory stores part or all of the necessary computer program or instructions for implementing the functions described in the third aspect above. The one or more processors can execute the computer program or instructions, causing the communication device to implement the methods in any possible design or implementation of the third aspect above when executed. The interface circuit is used to implement the communication functions within the communication device and / or the communication functions between the communication device and other devices or components.

[0066] In one possible design, the processor is used to communicate with other devices or components through the interface circuit.

[0067] In one possible design, the communication device may also include the memory.

[0068] For example, the communication device can be a terminal, or a communication module in the terminal, or a chip in the 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.

[0069] In a twelfth aspect, this application provides a communication device including an interface circuit and one or more processors. The one or more processors are coupled to a memory. The memory stores part or all of the necessary computer program or instructions for implementing the functions described in the fourth aspect above. The one or more processors are executable to carry out the computer program or instructions, causing the communication device to implement the methods in any possible design or implementation of the fourth aspect above. The interface circuit is used to implement the communication functions within the communication device and / or the communication functions between the communication device and other devices or components.

[0070] In one possible design, the processor is used to communicate with other devices or components through the interface circuit.

[0071] In one possible design, the communication device may also include the memory.

[0072] For example, the communication device can be a network device, or a communication module in a network device, or a chip in a network device 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.

[0073] In a thirteenth aspect, 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 to fourth aspects described above.

[0074] In a fourteenth aspect, 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 to fourth aspects described above. Attached Figure Description

[0075] Figure 1 is a schematic diagram of several scenarios in which the technical solution of this application can be applied;

[0076] Figure 2 shows a schematic diagram of the modules that the network device and terminal in this application may include;

[0077] Figure 3 is a flowchart illustrating a communication method provided in one embodiment of this application;

[0078] Figure 4 is a flowchart illustrating a communication method provided in another embodiment of this application;

[0079] Figure 5 is a structural schematic diagram of a communication device provided in an embodiment of this application;

[0080] Figure 6 is a structural schematic diagram of a communication device provided in another embodiment of this application. Detailed Implementation

[0081] Below, we will briefly explain the terminology used in the embodiments of this application. It should be understood that these explanations are only for the purpose of understanding the embodiments of this application and should not be construed as limiting the application in any way.

[0082] 1. Multiple-input multiple-output technology

[0083] Multiple-input multiple-output (MIMO) technology refers to the use of multiple transmit and receive antennas at both the transmitting and receiving ends. By employing a multi-layered parallel transmission mode, it provides a high data transmission rate, allowing signals to be transmitted and received through multiple antennas at both ends, thereby improving communication quality. It makes full use of spatial resources, achieving multiple transmissions and receptions through multiple antennas, and can significantly increase system channel capacity without increasing spectrum resources or antenna transmit power.

[0084] MIMO can be divided into single-user MIMO (SU-MIMO) and multi-user MIMO (MU-MIMO). Massive MIMO is based on the principle of multi-user beamforming. It deploys hundreds of antennas at the transmitting end, modulating the beams of dozens of target receivers. Through spatial signal isolation, it transmits dozens of signals simultaneously on the same frequency resource. Therefore, Massive MIMO technology can fully utilize the spatial freedom provided by large-scale antenna configuration, improving spectral efficiency.

[0085] 2. Channel reciprocity

[0086] Within a relatively short period of time (e.g., the coherence time of channel propagation), the channel fading experienced by signals on the uplink and downlink channels can be considered to be the same; this is the reciprocity of uplink and downlink channels. Based on the reciprocity of uplink and downlink channels, network devices can measure the uplink channel based on an uplink reference signal, such as a sounding reference signal (SRS), and estimate the downlink channel based on the uplink channel.

[0087] 3. Antenna Port

[0088] An antenna port is a logical concept. One antenna port corresponds to one or more antenna elements. Each antenna port can correspond to a reference signal (RS), therefore, an antenna port can also be called a port of a reference signal.

[0089] 4. Precoding technology

[0090] Transmitting devices (such as network devices) can process the signal to be transmitted using a precoding matrix that matches the channel state, given the known channel conditions. This precoding adapts the signal to the channel, allowing receiving devices (such as terminal devices) to eliminate inter-channel interference and improve transmission performance. Therefore, through precoding of the signal to be transmitted, the quality of the received signal (e.g., signal-to-interference-plus-noise ratio, SINR) is improved. Precoding technology enables transmitting devices and multiple receiving devices to transmit on the same time-frequency resources, thus achieving MU-MIMO.

[0091] 5. Precoding matrix indicator

[0092] The precoding matrix indicator (PMI) is used to indicate the precoding matrix. Network devices can determine the precoding matrix to be used when transmitting downlink data based on the PMI.

[0093] 6. Channel quality indication

[0094] Channel quality indicator (CQI) provides a reference for network devices in determining modulation and coding schemes. CQI feedback determines the coding and modulation methods, and network devices implement adaptive modulation coding (AMC) by judging the CQI value. The CQI value can be calculated from channel conditions, noise, and interference estimations. For example, if the CQI value fed back by the terminal device is large, the network device chooses a higher-order modulation scheme, such as 64 quadrature amplitude modulation (64QAM). Conversely, if the fed-back CQI value is small, the network device chooses a lower-order modulation scheme, such as quadrature phase shift keying (QPSK), and uses a coding scheme with greater redundancy (1 / 4 coding), thus reducing system throughput. When there is only one codeword, the terminal device only needs to feed back one CQI value; when using a 2-codeword multiple-input multiple-output (MIMO) system, two CQI values ​​need to be fed back.

[0095] 7. Rank Indicator

[0096] The rank indicator (RI) indicates the maximum number of uncorrelated data transmission channels in the spatial channel between terminal devices and network devices. In other words, it represents the number of data layers that a network device can transmit simultaneously to a terminal. A larger RI indicates more data layers can be transmitted simultaneously. The rank of the spatial channel is constantly changing, and the magnitude of the RI determines the choice of layer mapping method. Adaptation of the spatial rank is equivalent to adaptation of the layer mapping.

[0097] Figure 1 is a schematic diagram of the architecture of a communication system 1000 provided in an embodiment of this application. It is understood that the system architecture described in this application embodiment is for the purpose of more clearly illustrating the technical solutions of this application embodiment and does not constitute a limitation on the technical solutions provided in this application embodiment.

[0098] As shown in Figure 1, the communication system 1000 includes a radio access network (RAN) 100, wherein the RAN 100 includes at least one RAN node (110a and 110b in Figure 1, collectively referred to as 110), and may also include at least one terminal (120a-120j in Figure 1, collectively referred to as 120). The RAN 100 may also include other RAN nodes, such as wireless relay equipment and / or wireless backhaul equipment (not shown in Figure 1). The terminal 120 is wirelessly connected to the RAN node 110. Terminals and RAN nodes can be interconnected via wired or wireless means. The communication system 1000 may also include a core network 200. The RAN node 110 is connected to the core network 200 wirelessly or via wired means. The core network equipment in the core network 200 and the RAN node 110 in the RAN 100 can be independent and different physical devices, or they can be the same physical device integrating the logical functions of the core network equipment and the logical functions of the RAN node. The communication system 1000 may also include an Internet 300.

[0099] RAN100 can be an evolved universal terrestrial radio access (E-UTRA) system, a new radio (NR) system, or a future radio access system as defined in the 3rd generation partnership project (3GPP). RAN100 can also include two or more of the above-mentioned different radio access systems. RAN100 can also be an open RAN (O-RAN).

[0100] RAN nodes, also known as radio access network devices, RAN entities, or access nodes, are used to help terminals access communication systems wirelessly. In one application scenario, an RAN node can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation NodeB (gNB) in a 5G mobile communication system, or a base station in a future mobile communication system. RAN nodes can be macro base stations (as shown in Figure 1, 110a), micro base stations or indoor stations (as shown in Figure 1, 110b), relay nodes, or donor nodes.

[0101] In another application scenario, multiple RAN nodes can collaborate to help terminals achieve wireless access, with different RAN nodes implementing different functions of the base station. For example, a RAN node can be a central unit (CU), a distributed unit (DU), or a radio unit (RU). Here, the CU performs the functions of the base station's Radio Resource Control (RRC) and Packet Data Convergence Protocol (PDCP), and can also perform the functions of the Service Data Adaptation Protocol (SDAP). The DU performs the functions of the base station's Radio Link Control (RANC) and Medium Access Control (MAC) layers, and can also perform some or all of the physical layer functions. For specific descriptions of these protocol layers, refer to the relevant 3GPP technical specifications. The RU can be used to implement radio frequency signal transmission and reception. The CU and DU can be two independent RAN nodes or integrated into the same RAN node, such as within a baseband unit (BBU). The RU can be included in radio frequency equipment, such as in a remote radio unit (RRU) or an active antenna unit (AAU). The CU can be further divided into two types of RAN nodes: CU-control plane and CU-user plane.

[0102] In different systems, RAN nodes may have different names. For example, in an O-RAN system, a CU can be called an open CU (O-CU), a DU can be called an open DU (O-DU), and an RU can be called an open RU (O-RU). The RAN nodes in the embodiments of this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules. For example, a RAN node can be a server loaded with the corresponding software modules. The embodiments of this application do not limit the specific technology or device form used in the RAN nodes. For ease of description, a base station is used as an example of a RAN node in the following description.

[0103] A terminal is a device with wireless transceiver capabilities, capable of sending signals to or receiving signals from a base station. Terminals can also be called terminal equipment, user equipment (UE), mobile station, mobile terminal, etc. Terminals can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, etc. Terminals can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, airplanes, ships, robots, robotic arms, smart home devices, etc. The embodiments of this application do not limit the specific technology or device form used in the terminal.

[0104] Base stations and terminals can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can be deployed on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of the base stations and terminals.

[0105] The roles of base stations and terminals can be relative. For example, the helicopter or drone 120i in Figure 1 can be configured as a mobile base station. For terminals 120j that access the wireless access network 100 through 120i, terminal 120i is a base station; however, for base station 110a, 120i is a terminal, meaning that 110a and 120i communicate via a wireless air interface protocol. Of course, 110a and 120i can also communicate via a base station-to-base station interface protocol. In this case, relative to 110a, 120i is also a base station. Therefore, both base stations and terminals can be collectively referred to as communication devices. 110a and 110b in Figure 1 can be called communication devices with base station functions, and 120a-120j in Figure 1 can be called communication devices with terminal functions.

[0106] Communication between base stations and terminals, between base stations, and between terminals can be conducted using licensed spectrum, unlicensed spectrum, or both simultaneously. Communication can be conducted using spectrum below 6 GHz, spectrum above 6 GHz, or both simultaneously. The embodiments of this application do not limit the spectrum resources used for wireless communication.

[0107] In the embodiments of this application, the functions of the base station can be executed by modules (such as chips) within the base station, or by a control subsystem that includes base station functions. This control subsystem, including base station functions, can be a control center in the aforementioned application scenarios such as smart grids, industrial control, intelligent transportation, and smart cities. Similarly, the functions of the terminal can be executed by modules (such as chips or modems) within the terminal, or by a device that includes terminal functions.

[0108] For example, as shown in Figure 2, the network device and terminal in this application may include the following modules:

[0109] Radio Resource Control (RRC) Signaling Interaction Module: This module is used by network devices and terminals to send and receive RRC signaling. For example, a network device sends RRC signaling to a terminal, and the terminal receives RRC signaling from the network device.

[0110] Media Access Control (MAC) Signaling Interaction Module: This module is used by network devices and terminals to send and receive MAC control element (CE) signaling. For example, a network device sends MAC CE signaling to a terminal, and the terminal receives MAC CE signaling from the network device.

[0111] Physical layer (PHY) signaling and data interaction module: This module is used by network devices and terminals to send and receive uplink / downlink control signaling and uplink / downlink data.

[0112] For example, network devices send physical downlink control channel (PDCCH) messages to terminal devices, such as downlink control information (DCI) within the PDCCH; network devices also send physical downlink shared channel (PDSCH) messages to terminal devices, such as downlink data within the PDSCH. Terminal devices send physical uplink control channel (PUCCH) messages to network devices, such as uplink control information (UCI) within the PUCCH; and terminal devices also send physical uplink shared channel (PUSCH) messages to network devices, such as uplink data within the PUSCH.

[0113] It should be understood that the modules shown in Figure 2 are merely exemplary, and network devices and terminal devices may also include other communication modules, such as radio link control (RLC) modules, packet data convergence protocol (PDCP) modules, or service data adaptation protocol (SDAP) modules, etc. This application embodiment does not specifically limit these.

[0114] When a network device transmits data (also known as downlink data) to a terminal, it can process the downlink data using a precoding matrix that matches / adapts to the channel. This ensures that the downlink data, after processing by the precoding matrix, is adapted to the channel. Essentially, the channel matrix corresponding to the precoded downlink data can be equivalent to a diagonal matrix, thereby preventing interference between parallel data streams during terminal demodulation and improving the terminal's reception performance. In this application, for ease of understanding, the precoding matrix used by the network device that matches the channel is also referred to as the target precoding matrix.

[0115] Below, we introduce two ways in which network devices can obtain the target precoding matrix.

[0116] I. First Implementation Method

[0117] Network devices can send reference signals to terminals. Correspondingly, the terminal measures the reference signal to estimate the downlink channel matrix H, then determines the ideal precoding matrix based on the downlink channel H and quantizes the ideal precoding matrix into a Precoding Indicator (PMI), which is then reported to the network device. Upon receiving the PMI, the network device determines the precoding matrix indicated by the PMI as the target precoding matrix. In other words, the ideal precoding matrix can be considered the precoding matrix before quantization into the PMI.

[0118] For example, the reference signal sent to the terminal by the network device described above is CSI-RS. It should be understood that the examples herein are merely illustrative and should not be construed as limiting this application in any way.

[0119] For example, the CSI content reported by the network device terminal may include PMI and CQI. PMI is used by the network device to determine the target precoding matrix, and CQI is used to indicate to the network device the channel quality determined by the terminal based on the selected PMI. Correspondingly, the terminal performs measurements based on the CSI-RS sent by the network device, obtains PMI and CQI, and reports them to the network device. After receiving the PMI and CQI reported by the terminal, the network device determines the target precoding matrix based on the PMI and the MCS corresponding to the CQI based on the CQI, and then sends downlink data to the terminal based on the target precoding matrix and the MCS. It should be noted that the inclusion of PMI and CQI in the CSI content described here does not constitute a limitation of this application. For example, the CSI content may also include RI, LI, etc. The descriptions of RI and LI can be found in related technologies and will not be repeated here.

[0120] For example, after the terminal estimates the downlink channel matrix H based on the reference signal sent by the network device, the terminal can obtain the following result by performing SVD decomposition on the downlink channel matrix H: H = U·S·V H

[0121] Among them, U and V H Let S be a unitary matrix, and S be a diagonal matrix. Its non-zero elements (i.e., elements on the diagonal) are the singular values ​​of the downlink channel matrix H. These singular values ​​are typically arranged in descending order. Therefore, the terminal can use the right unitary matrix V as a basis for... H The conjugate transpose V yields the ideal precoding matrix, also known as the right unitary matrix or right singular matrix.

[0122] For example, after determining the ideal precoding matrix, the terminal can determine a precoding matrix that is relatively close to the ideal precoding matrix, and then feed back the Precoding Interface (PMI) corresponding to the precoding matrix that is relatively close to the ideal precoding matrix to the network device. After receiving the PMI, the network device can obtain the aforementioned precoding matrix that is relatively close to the ideal precoding matrix based on the PMI fed back by the terminal, that is, obtain the target precoding matrix. At this point, the network device can process downlink data based on the target precoding matrix that is adapted to the channel.

[0123] It should be noted that when a network device configures a terminal to report a Precoding Indicator (PMI), the terminal considers which flows have less interference when determining the PMI. This allows the network device to identify the target flow corresponding to the target precoding matrix after receiving the PMI reported by the terminal. Furthermore, when the network device sends downlink data to the terminal, it transmits on these target flows. For example, after the terminal performs SVD decomposition on the downlink channel matrix H, the conjugate transpose of the resulting right unitary matrix includes four columns, each of which can be called a precoding vector. These four precoding vectors correspond to four flows. The target precoding matrix indicated in the PMI sent by the terminal includes precoding vectors corresponding to the first and third columns of these four columns. Therefore, the network device uses the first and third flows to send downlink data to the terminal, i.e., it uses the first and third flows out of the four flows to send downlink data to the terminal.

[0124] In addition, it is understood that the terminal's determination of the ideal precoding matrix based on SVD decomposition is only one implementation method and does not constitute a limitation of this application. For example, the terminal may also use other methods to determine the ideal precoding matrix after determining the signal matrix H.

[0125] For example, when the CSI reported by the terminal includes PMI, existing protocols divide the reported CSI content into two parts. The first part includes the portion determining the feedback length, and the second part includes the portion whose feedback length can only be determined based on the first part. For instance, for CSI reporting based on a Type I codebook, the first part includes CRI, RI, and the CQI of the first codeword, and the second part includes PMI, LI, and the CQI of the second codeword. For CSI reporting based on a Type II codebook or an enhanced Type II codebook, the first part includes CRI, RI, CQI, and the length indication of the second part, and the second part includes PMI and LI. When the terminal's reporting resources are insufficient, the terminal can discard the reported content in the second part according to the priority order defined by the standard.

[0126] II. Second Implementation Method

[0127] The CSI reported by the network device configuration terminal does not include PMI. For example, the CSI reported by the base station configuration terminal includes CRI, RI, and CQI. Correspondingly, the network device obtains the downlink channel matrix H based on the reciprocity of the uplink and downlink channels, and then determines the target precoding matrix based on the downlink channel matrix H. For example, the network device obtains the uplink channel matrix based on the sounding reference signal (SRS) sent by the terminal, and then obtains the downlink channel matrix H based on the channel reciprocity of the uplink and downlink channels.

[0128] In this implementation, to determine the target flow corresponding to the target precoding matrix, the network device autonomously selects certain flows and transmits precoded reference signals on these flows, indicating to the terminal which flows these precoded reference signals were transmitted on. After receiving these precoded reference signals, the terminal performs measurements to determine the target flow from these flows and feeds back the target flow to the network device. This allows the network device to determine the target precoding matrix based on the downlink channel matrix H and the target flow. Understandably, compared to the first implementation, this second implementation requires the network device to transmit precoded reference signals to the terminal. Since these precoded reference signals are UE-level reference signals, if every terminal is configured this way, it will result in high signaling overhead for the network device.

[0129] The above describes the relevant content of existing network devices sending downlink data to terminals based on the target precoding matrix.

[0130] Currently, when determining the target precoding matrix based on the downlink channel matrix H, the following scheme has been proposed: As the number of transmitter antennas approaches infinity, the small-scale fading between different transmit / receive antenna pairs tends to be independent, meaning the channel responses between different transmit / receive antenna pairs tend to be orthogonal. This phenomenon is called channel hardening. Under channel hardening, the existing process of determining the ideal precoding matrix based on SVD decomposition and obtaining the target precoding matrix after quantization of the PMI feedback ideal precoding matrix is ​​no longer needed. Network devices can directly determine the target precoding matrix as the conjugate transpose of the downlink channel matrix H, making the channel matrix corresponding to the downlink data after precoding equivalent to a diagonal matrix.

[0131] For example, massive MIMO is an effective means proposed by NR to improve spatial resolution, increase spatial multiplexing dimensions, and obtain array gain. In related work, the 6425–7125 MHz band has been defined as the U6G licensed band. Compared with typical carrier frequencies such as 2.6 GHz and 3.5 GHz, with the increase of the U6G band carrier frequency, the wavelength is further reduced and the antenna spacing is smaller. The number of antennas in the base station can continue to evolve towards ultra-massive MIMO. Inter-user interference is reduced in the U6G band, and the channel tends to harden to a certain extent.

[0132] However, it is understandable that in real-world scenarios, although the number of antennas increases and the channel tends to harden, there is still a significant gap compared to the number of antennas approaching infinity. Therefore, if the conjugate transpose of the downlink channel matrix H is directly used as the target precoding matrix, there may be decoding errors at the receiver, resulting in poor transmission performance.

[0133] Additionally, it's understandable that current technology may present challenges in terms of terminal complexity and power consumption when configuring network devices to report PMIs. For example, when a terminal is near the center of a cell or its channel is stable, the downlink channel corresponding to adjacent reported PMIs doesn't change significantly. In such cases, reporting PMIs is not very useful, and the impact of the terminal not reporting PMIs on network throughput is minimal.

[0134] In view of this, this application provides a communication method in which the network device can determine the precoding matrix to be used when sending downlink data to the terminal even when the terminal does not report PMI, thereby reducing the terminal power consumption while ensuring the terminal's receiving performance.

[0135] The communication method provided in the embodiments of this application will now be described with reference to the accompanying drawings. It is understood that this application uses network devices and terminals as examples of the execution subjects in the interaction illustration, but this application does not limit the execution subjects of the interaction illustration. For example, the method executed by the network device in this application can also be implemented by modules (e.g., circuits, chips, or chip systems) in the network device, or by logical nodes, logical modules, or software that can implement all or part of the functions of the network device; the method executed by the terminal in this application can also be implemented by a communication module in the terminal or by circuits or chips (such as modem chips (also known as baseband chips), or SoC chips containing modem cores, or SIP chips) in the terminal responsible for communication functions.

[0136] Figure 3 is a schematic flowchart of a communication method provided in an embodiment of this application. As shown in Figure 3, the method includes:

[0137] S310, the network device sends a reference signal to the terminal, and the terminal receives the reference signal accordingly; the reference signal is used to determine the CSI.

[0138] For example, the reference signal is CSI-RS.

[0139] In one example, the network device can configure the terminal to report CSI without the terminal reporting PMI. For instance, the CSI reported by the network device's configuration terminal may include CRI, RI, and CQI.

[0140] S320, the terminal sends a first CSI to the network device, and the network device receives the first CSI accordingly; the first CSI includes first information and at least two of the following CSIs: information for indicating the first channel quality, information for indicating the second channel quality, and second information, wherein the first channel quality corresponds to the first precoding matrix, the second channel quality corresponds to the second precoding matrix, the second information indicates the deviation between the first channel quality and the second channel quality, and the first information is used to indicate the target flow corresponding to the first channel quality and the target flow corresponding to the second channel quality.

[0141] The aforementioned first CSI refers to the CSI determined by the terminal after measuring the received reference signal. In this embodiment, the UCI carrying the first CSI is also referred to as the first UCI. Therefore, the terminal sending the first CSI to the network device can also be replaced by the terminal sending the first UCI to the network device, where the first UCI includes the first CSI. In other words, the first UCI in this embodiment can be considered as a UCI that includes at least two of the following: first information, information for indicating first channel quality, information for indicating second channel quality, and second information.

[0142] In this embodiment, when determining the first precoding matrix and the second precoding matrix based on the downlink channel matrix, the first precoding matrix and the second precoding matrix are determined using different methods. For example, in this application, the method for determining the first precoding matrix is ​​referred to as the first method, and the method for determining the second precoding matrix is ​​referred to as the second method. For example, the first precoding matrix is ​​determined based on the conjugate transpose of the downlink channel matrix, and the second precoding matrix is ​​determined based on the right singular matrix obtained after SVD of the downlink channel matrix.

[0143] In this embodiment, when the terminal measures the received reference signal and reports the first CSI, the first CSI includes first information and at least two of the following CSIs: information for indicating the first channel quality, information for indicating the second channel quality, and second information.

[0144] For example, the information used to indicate channel quality is CQI. Correspondingly, the information used to indicate the first channel quality is, for example, a first CQI, and the information used to indicate the second channel quality is, for example, a second CQI. It should be noted that the use of CQI to indicate channel quality here is merely an example and does not constitute a limitation of this application. For example, other indicators that can be used to indicate / evaluate channel quality can also be used.

[0145] The first channel quality corresponds to the first precoding matrix, and can also be understood as being determined / calculated based on the first precoding matrix. Alternatively, it can be understood as the channel quality corresponding to when the network device sends downlink data to the terminal based on the first precoding matrix.

[0146] The second channel quality corresponds to the second precoding matrix, and can also be understood as being determined / calculated based on the second precoding matrix. Alternatively, it can be understood as the channel quality corresponding to when the network device sends downlink data to the terminal based on the second precoding matrix.

[0147] Taking the example of a first precoding matrix determined by the conjugate transpose of the downlink channel matrix and a second precoding matrix determined by the right singular matrix obtained after SVD of the downlink channel matrix, the implementation of the terminal determining the first and second precoding matrices is explained. For example, the terminal determines the first precoding matrix by: obtaining the downlink channel matrix based on measurements of the received reference signal; obtaining the conjugate transpose of the downlink channel matrix based on the downlink channel matrix; and then determining the first precoding matrix based on the conjugate transpose of the downlink channel matrix and the target flow determined during measurement. The terminal determines the second precoding matrix by: obtaining the downlink channel matrix based on measurements of the received reference signal; performing SVD decomposition on the downlink channel matrix; and then determining the second precoding matrix based on the right singular matrix obtained after SVD decomposition and the target flow determined during measurement.

[0148] In this context, the first information is used to indicate the target flow corresponding to the first channel quality and the target flow corresponding to the second channel quality. Since the first channel quality is obtained based on the first precoding matrix and the second channel quality is obtained based on the second precoding matrix, the first information used to indicate the target flow corresponding to the first channel quality and the target flow corresponding to the second channel quality can also be replaced with the first information used to indicate the target flow corresponding to the first precoding matrix and the target flow corresponding to the second precoding matrix. That is, when the terminal measures the received reference signal and reports the first CSI, it informs the network device through the first CSI the target flow selected when determining the first precoding matrix based on the downlink channel matrix and the target flow selected when determining the second precoding matrix. Thus, the network device can determine the first and second precoding matrices based on the downlink channel matrix and the target flow. For example, the network device can determine the downlink channel matrix based on the channel reciprocity of the uplink and downlink channels.

[0149] Understandably, by reporting the first piece of information, on the one hand, the network device can determine the target precoding matrix to use even if the terminal does not report the PMI, which can reduce the terminal's power consumption. On the other hand, the network device does not need to send UE-level precoded reference signals to the terminal, thus reducing the complexity of the network device in determining the target flow and saving the overhead of the network device sending reference signals.

[0150] In this embodiment, the second information is used to indicate the deviation between the first channel quality and the second channel quality. Specifically, after receiving the reference signal, the terminal determines the first precoding matrix and the second precoding matrix based on the reference signal. Then, it calculates the first indicator (e.g., the first CQI) and the second indicator (e.g., the second CQI) corresponding to the first precoding matrix for measuring channel quality, respectively. Finally, it feeds back the first information, and at least two of the first indicator, the second indicator, and the deviation between the first and second indicators, to the network device. For example, when the terminal feeds back at least two of the first CQI, the second CQI, and the deviation between the first and second CQI to the network device, the terminal feeds back the first CQI and the deviation between the first and second CQI, so that the network device can determine the second CQI based on the first CQI and the deviation, thereby determining the channel quality corresponding to the two precoding matrices. For example, the terminal feeds back the deviation between the second CQI and the first and second CQIs to the network device, so that the network device can determine the first CQI based on the first CQI and the deviation, thereby determining the channel quality corresponding to the two precoding matrices. Alternatively, the terminal can directly feed back the first and second CQIs to the network device, allowing the network device to directly determine the channel quality corresponding to the two precoding matrices. It is understood that when the terminal feeds back at least two of the following information to the network device—information indicating the first channel quality, information indicating the second channel quality, and second information—it is for the terminal to determine the first channel quality corresponding to the first precoding matrix and the second channel quality corresponding to the second precoding matrix. Therefore, in this application, the terminal sends a first CSI, which includes at least two of the following CSIs: information indicating the first channel quality, information indicating the second channel quality, and second information. Alternatively, the first CSI can include indication information for the network device to determine the first and second channel quality.

[0151] S330, the network device sends downlink data to the terminal based on the first CSI.

[0152] For example, a network device transmits downlink data based on a first CSI, including: determining the transmission method of the downlink data based on the first CSI; and transmitting the downlink data based on the transmission method.

[0153] For example, the transmission method of downlink data is determined based on the first CSI, such as whether to use a first precoding matrix or a second precoding matrix to precode the downlink data. Understandably, after receiving the first CSI, the network device can determine the first precoding matrix and the second precoding matrix based on the downlink channel matrix determined by the channel reciprocity of the uplink and downlink channels and the target stream indicated by the terminal, respectively. Then, based on the channel quality (i.e., the first channel quality) corresponding to sending downlink data to the terminal using the first precoding matrix, the channel quality (i.e., the second channel quality) corresponding to sending downlink data to the terminal using the second precoding matrix, and the deviation between these two channel qualities, the precoding matrix to be used when sending downlink data to the terminal is determined. For example, the precoding matrix with better channel quality between the first and second precoding matrices can be selected to send downlink data to the terminal, thereby improving the terminal's reception performance.

[0154] Optionally, if the network device determines to use a first precoding matrix to process the downlink data sent to the terminal, and the first precoding matrix is ​​determined based on the conjugate transpose of the downlink channel matrix, then the network device can also adjust some other parameters based on the deviation between the first channel quality corresponding to the first precoding matrix and the second channel quality corresponding to the second precoding matrix. For example, it can adjust the modulation and coding scheme (MCS) based on the difference between the first CQI and the second CQI, thus improving the terminal's reception performance. For example, the first precoding matrix is ​​a precoding matrix determined based on the conjugate transpose of the downlink channel matrix, and the second precoding matrix is ​​a precoding matrix determined based on the right singular matrix obtained after SVD of the downlink channel matrix. After receiving the first CSI, the network device can adjust some network parameters based on the deviation, such as adjusting the MCS based on the deviation between the first CQI and the second CQI, thereby eliminating interference from non-ideal channel hardening residues and improving the terminal's reception performance.

[0155] In some implementations, method 300 may further include S301: the terminal sends first capability information to the network device, the first capability information being used to indicate that the terminal supports the capability to report CSI based on the first CSI.

[0156] The aforementioned first capability information is used to indicate to the terminal the ability to report CSI based on the first CSI. Alternatively, it can be replaced with: the first capability information is used to indicate to the terminal the ability to report CSI based on the first UCI. That is, the terminal uses the first capability information to indicate to the network device that it supports a first UCI that does not report PMI.

[0157] In some implementations, before S310, method 300 also includes S302, in which the network device sends third information to the terminal, the third information being used to indicate whether the terminal reports CSI based on the first CSI.

[0158] The aforementioned third information, used to indicate whether the terminal reports CSI based on the first CSI, can also be replaced with: the third information is used to indicate whether the terminal reports CSI based on the first UCI. That is, the third information is used to indicate whether the terminal enables first UCI CSI reporting. For example, if the third information indicates that first UCI CSI reporting is enabled, the terminal will only report CSI based on the first UCI when reporting the first CSI.

[0159] Optionally, the third information can be carried in the RRC signaling, for example, in the CSI-ReportConfig field of the RRC signaling.

[0160] For example, a network device can send third information to a terminal when it determines that the channel is hardening. That is, it can be assumed that in a scenario where the channel is hardening, the network device configures the terminal to enable CSI reporting via the first UCI.

[0161] Optionally, in this embodiment, after determining the first channel quality corresponding to the first precoding matrix and the first channel quality corresponding to the second precoding matrix, when the terminal reports the first CSI to the network device via the first UCI, it may also include fourth information in the first CSI. The fourth information is used to indicate a recommended precoding matrix, which can be either the first precoding matrix or the second precoding matrix. That is, the terminal can recommend a precoding matrix that it considers better to the network device based on the first and second channel quality. One implementation method for the terminal to determine the recommended precoding matrix includes: the terminal device determines the recommended precoding matrix through a threshold predefined by the protocol or indicated by the network device.

[0162] For example, if the terminal recommends using a second precoding matrix, in one implementation, the network device processes the data sent to the terminal based on the second precoding matrix. Alternatively, in another implementation, the network device still processes the data sent to the terminal based on the first precoding matrix; that is, in this other implementation, although the terminal recommends the second precoding matrix, the network device does not use it.

[0163] Figure 4 is a schematic flowchart of a communication method provided in another embodiment of this application. As shown in Figure 4, the method includes:

[0164] S410, the network device sends the fifth information to the terminal, and the terminal receives the fifth information accordingly; the fifth information is used to instruct the reporting of the second CSI, which includes PMI and CQI.

[0165] In this embodiment, when the network device configuration terminal reports CSI, the reported CSI includes PMI, that is, the network device configuration terminal reports PMI and CQI. It is understood that including PMI and CQI in the CSI here does not constitute a limitation of this application. For example, the reported CSI may include more components, such as RI and / or LI in addition to PMI and CQI.

[0166] S420, the terminal sends a third CSI to the network device. The third CSI includes a first indication information, a second indication information, and a CQI. The first indication information is used to indicate that the PMI should be dropped, and the second indication information is used to indicate the target flow used when determining the CQI.

[0167] The second CSI can be understood as the CSI that includes PMI, and the third CSI can be understood as the CSI that does not include PMI. In other words, the second CSI can be understood as the CSI corresponding to when the terminal reports PMI, and the third CSI can be understood as the CSI corresponding to when PMI is not reported.

[0168] The aforementioned second or third CSI can be the CSI determined by the terminal based on the measurement of the reference signal sent by the network device.

[0169] In this embodiment, the UCI carrying the second CSI is referred to as the second UCI. Correspondingly, the fifth information is used to indicate the reporting of the second CSI, which includes PMI and CQI. Alternatively, the fifth information can be used to indicate the reporting of CSI based on the second UCI, which includes PMI and CQI.

[0170] In this embodiment, the UCI carrying the third CSI is referred to as the third UCI. Correspondingly, the terminal sends the third CSI to the network device, which includes the first indication information, the second indication information, and the CQI. Alternatively, the terminal can send the third UCI to the network device, which includes the first indication information, the second indication information, and the CQI.

[0171] In this embodiment, CQI refers to the channel quality calculated by the terminal based on a determined PMI. For example, taking SVD decomposition to determine PMI as an example, the terminal determines PMI by: determining the downlink channel matrix based on the reference signal sent by the network device, performing SVD decomposition on the downlink channel matrix, and then determining the PMI based on the right singular matrix obtained after SVD decomposition and the target flow determined during measurement.

[0172] In this embodiment, although the network device configures the terminal to report PMI, the terminal may choose not to report PMI. For example, when the terminal determines / judges that the channel stability condition is met, it decides not to report PMI. That is, when the terminal determines / judges that the channel stability condition is met, the terminal sends a third CSI to the network device. Channel stability can be understood as the downlink channel matrix remaining almost unchanged. For example, the channel stability condition includes one or more of the following: the reference signal receiving power (RSRP) is greater than a first threshold, the terminal's moving speed is less than or equal to a second threshold, and the difference between the predicted channel quality and the actual channel quality is less than or equal to a third threshold.

[0173] Optionally, when the terminal determines that the channel stability conditions are not met, it sends a second CSI, i.e., reports the PMI. Correspondingly, the network device determines the target precoding matrix based on the PMI. For example, if the terminal determines that the downlink channel change no longer meets the conditions of stable or slow change, the terminal actively resumes PMI reporting. In this implementation, RRC reconfiguration for PMI reporting is not required, thus avoiding increased signaling overhead.

[0174] Understandably, for network devices, determining the target precoding matrix requires knowledge of the downlink channel matrix and the target flow; that is, the network device can determine the target precoding matrix based on the downlink channel matrix and the target flow. The downlink channel matrix can be determined by the network device based on the channel reciprocity of the uplink and downlink channels. However, when the terminal does not report the PMI, the network device cannot determine the target flow to use, thus preventing the determination of the target precoding matrix. Therefore, in this embodiment, when the terminal does not report the PMI, when reporting the third CSI, the terminal includes not only the determined CQI but also first and second indication information. The first indication information indicates that the PMI should be discarded to align the total length of the third UCI with the network device, and the second indication information indicates the target flow used when determining the CQI (i.e., the second indication information indicates the target flow selected by the network device when determining the target precoding based on the downlink channel matrix). In this way, when the network device receives the third CSI, the network device can know that the terminal has not reported PMI. Then, based on the second indication information, the network device can know the target stream selected by the terminal, so that the network device can determine the target precoding matrix based on the target stream and the downlink channel matrix, and send data to the terminal based on the target precoding matrix.

[0175] In some implementations, method 400 may further include S401: the terminal sends second capability information to the network device, the second capability information indicating that the terminal supports the capability to report CSI based on the third CSI. In this application, the second capability information indicating that the terminal supports the capability to report CSI based on the third CSI can also be replaced by: the second capability information indicating that the terminal supports the capability to report CSI based on the third UCI. That is, the terminal indicates to the network device through the second capability information that it supports the third UCI that does not report PMI.

[0176] In some implementations, prior to S410, method 400 also includes S402, whereby the network device sends a sixth message to the terminal, the sixth message indicating whether the terminal reports a CSI based on the third CSI.

[0177] The sixth information, used to indicate whether the terminal reports CSI based on the third CSI, can also be replaced with: the sixth information is used to indicate whether the terminal reports CSI based on the third UCI. That is, the sixth information is used to indicate whether the terminal enables third UCI CSI reporting. For example, if the sixth information indicates that third UCI CSI reporting is enabled, the terminal will only report CSI based on the third UCI when it is time to report the third CSI.

[0178] Optionally, the sixth information can be carried in the RRC signaling, for example, in the CSI-ReportConfig field of the RRC signaling.

[0179] As can be seen, by using the above method 400, the target precoding matrix can be determined by the network device even when the terminal does not report PMI to the network device, for example, when the channel is stable and the terminal has sufficient reporting resources. Furthermore, since the terminal does not need to report PMI, the reporting overhead is saved, thereby reducing the terminal's power consumption.

[0180] In summary, it can be seen that in this embodiment, when the terminal does not report PMI to the network device, it will indicate the target flow to the network device based on the measurement of the reference signal, so that the network device can determine the target precoding matrix to be used based on the target flow and the downlink channel matrix.

[0181] The communication method of the embodiments of this application has been described in detail above. The apparatus provided by the embodiments of this application will be described in detail below with reference to FIG5 and FIG6.

[0182] Figure 5 is a structural schematic diagram of the communication device provided in an embodiment of this application. Specifically, as shown in Figure 5, the device 500 includes: a transceiver module 501 and a processing module 502.

[0183] In the first embodiment of the device, the communication device 500 can be a terminal-side device, such as a terminal or a communication module in the terminal, or a circuit or chip in the terminal that is responsible for communication functions.

[0184] For example, transceiver module 501 is used to: receive a reference signal, the reference signal being used to determine CSI; transceiver module 501 is also used to: transmit a first CSI, the first CSI including first information and at least two of the following CSIs: information for indicating first channel quality, information for indicating second channel quality, and second information, the first channel quality corresponding to a first precoding matrix, the second channel quality corresponding to a second precoding matrix, the second information indicating the deviation between the first channel quality and the second channel quality, and the first information being used to indicate the target stream corresponding to the first channel quality and the target stream corresponding to the second channel quality.

[0185] For example, the processing module 502 can be used to determine the first channel quality, the second channel quality, and the deviation between the first channel quality and the second channel quality.

[0186] In one possible design, the first precoding matrix is ​​determined based on the conjugate transpose of the downlink channel matrix, and the second precoding matrix is ​​determined based on the right singular matrix obtained by SVD of the downlink channel matrix.

[0187] In one possible design, the transceiver module 501 is also used to: receive third information, which indicates whether to report CSI based on the first CSI.

[0188] In one possible design, the transceiver module 501 is also used to: send first capability information, which indicates the capability to support reporting CSI based on the first CSI.

[0189] In one possible design, the first CSI also includes fourth information, which indicates a recommended precoding matrix, either the first precoding matrix or the second precoding matrix.

[0190] In one possible design, the reference signal is CSI-RS.

[0191] In the second embodiment, the communication device 500 can be a network-side device, such as a network device or a communication module in a network device, or a circuit or chip in a network device that is responsible for communication functions.

[0192] For example, transceiver module 501 is used to: transmit a reference signal, the reference signal being used to determine CSI; transceiver module 501 is also used to: receive a first CSI, the first CSI including first information and at least two of the following CSIs: information for indicating a first channel quality, information for indicating a second channel quality, the first information, the first channel quality corresponding to a first precoding matrix, the second channel quality corresponding to a second precoding matrix, the second information indicating the deviation between the first channel quality and the second channel quality, the first information being used to indicate the target stream corresponding to the first channel quality and the target stream corresponding to the second channel quality; transceiver module 501 is also used to: transmit downlink data based on the first CSI.

[0193] For example, the processing module 502 is used to: determine the target precoding matrix to be used when sending downlink data to the terminal based on the target stream indicated by the second information and the downlink channel matrix.

[0194] In one possible design, the first precoding matrix is ​​determined based on the conjugate transpose of the downlink channel matrix, and the second precoding matrix is ​​determined based on the right singular matrix obtained by SVD of the downlink channel matrix.

[0195] In one possible design, the transceiver module 501 is specifically used to transmit downlink data based on a first precoding matrix and an MCS; wherein the target MCS is related to the deviation.

[0196] In one possible design, the transceiver module 501 is also used to: send third information, which indicates whether to report CSI based on the first CSI.

[0197] In one possible design, the transceiver module 501 is also used to: receive first capability information, which indicates the capability to support reporting CSI based on the first CSI.

[0198] In one possible design, the first CSI also includes fourth information, which indicates a recommended precoding matrix, either the first precoding matrix or the second precoding matrix.

[0199] In one possible design, the reference signal is CSI-RS.

[0200] In the third embodiment, the communication device 500 can be a terminal-side device, such as a terminal or a communication module in a terminal, or a circuit or chip in a terminal that is responsible for communication functions.

[0201] For example, the transceiver module 501 is used to: receive fifth information, which is used to instruct the reporting of a second CSI, the second CSI including PMI and CQI; the transceiver module 501 is also used to: send a third CSI, which includes a first indication information, a second indication information and a CQI, the first indication information being used to instruct the discarding of PMI, and the second indication information being used to instruct the target stream used when determining the CQI.

[0202] For example, processing module 502 can be used to determine CQI and target flow.

[0203] In one possible design, transceiver module 501 is also used to: send a third CSI if it is determined that the channel stability condition is met.

[0204] In one possible design, the conditions for channel stability include one or more of the following: RSRP is greater than a first threshold, and the terminal's moving speed is less than or equal to a second threshold.

[0205] In one possible design, transceiver module 501 is also used to: receive sixth information, which indicates whether to report CSI based on third CSI.

[0206] In one possible design, transceiver module 501 is also used to: send second capability information, which indicates the capability to support CSI reporting based on third CSI.

[0207] In one possible design, the transceiver module 501 is also used to: send a second CSI if it is determined that the channel stability condition is not met.

[0208] For example, the processing module 502 can be used to determine whether the conditions for channel stability are met.

[0209] In the second embodiment, the communication device 500 can be a network-side device, such as a network device or a communication module in a network device, or a circuit or chip in a network device that is responsible for communication functions.

[0210] For example, transceiver module 501 is used to: send fifth information, which is used to instruct the terminal to report a second CSI, the second CSI including PMI and CQI; transceiver module 501 is also used to: receive a third CSI, the third CSI including a first indication information, a second indication information and CQI, the first indication information being used to instruct the PMI to be discarded, and the second indication information being used to instruct the network device to use the target flow when determining the CQI.

[0211] For example, processing module 502 is used to determine the target precoding matrix to be used based on the target stream indicated by the second indication information and the downlink channel matrix H.

[0212] In one possible design, transceiver module 501 is also used to: send a sixth message, which indicates whether to report CSI based on the third CSI.

[0213] In one possible design, transceiver module 501 is also used to: receive second capability information, which indicates the capability to support CSI reporting based on third CSI.

[0214] In one possible design, transceiver module 501 is also used to: receive the second CSI.

[0215] Figure 6 is a structural schematic diagram of another communication device provided in an embodiment of this application. The device shown in Figure 6 can be used to perform the method described in any of the foregoing embodiments.

[0216] As shown in Figure 6, the device 600 of this embodiment includes a memory 601 and a processor 602. In one implementation, the device 600 further includes a communication interface 603 and a bus 604. The memory 601, processor 602, and communication interface 603 are interconnected via the bus 604.

[0217] The memory 601 can be a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 601 can store programs, and when the program stored in the memory 601 is executed by the processor 602, the processor 602 performs the various steps of the method shown in FIG3 or FIG4.

[0218] The processor 602 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, used to execute relevant programs to implement the method shown in FIG3 or FIG4 of the embodiments of this application.

[0219] The processor 602 can also be an integrated circuit chip with signal processing capabilities. In implementation, each step of the method in Figure 3 or Figure 4 of this application embodiment can be completed by the integrated logic circuitry in the processor 602 or by software instructions.

[0220] The processor 602 described above can also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or a conventional processor, etc.

[0221] The steps of the method disclosed in the embodiments of this application can be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory 601. The processor 602 reads the information in memory 601 and, in conjunction with its hardware, completes the functions required by the units included in the device of this application. For example, it can execute the various steps / functions of the embodiments shown in FIG3 or FIG4.

[0222] The communication interface 603 can use, but is not limited to, transceivers to enable communication between the device 600 and other devices or communication networks.

[0223] Bus 604 may include a pathway for transmitting information between various components of device 600 (e.g., memory 601, processor 602, communication interface 603).

[0224] It should be understood that the device 600 shown in the embodiments of this application can be deployed in network devices or terminals.

[0225] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or 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 website, computer, server, or data center via wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be a usable medium accessible to a computer or a data storage device such as a server or data center containing one or more sets of usable media. The usable medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. A semiconductor medium can be a solid-state drive.

[0226] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0227] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0228] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not limit the implementation process of the embodiments of this application.

[0229] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0230] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0231] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0232] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0233] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0234] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

Claims

1. A communication method, characterized in that, include: Receive a reference signal, the reference signal being used to determine Channel State Information (CSI); Send a first CSI, the first CSI including first information and at least two of the following CSIs: information for indicating a first channel quality, information for indicating a second channel quality, and second information, wherein the first channel quality corresponds to a first precoding matrix, the second channel quality corresponds to a second precoding matrix, the second information indicates the deviation between the first channel quality and the second channel quality, and the first information is used to indicate the target stream corresponding to the first channel quality and the target stream corresponding to the second channel quality.

2. The method according to claim 1, characterized in that, The first precoding matrix is ​​determined based on the conjugate transpose of the downlink channel matrix, and the second precoding matrix is ​​determined based on the right singular matrix obtained by Singular Value Decomposition (SVD) of the downlink channel matrix.

3. The method according to claim 1 or 2, characterized in that, The method further includes: Receive third information, which indicates whether to report CSI based on the first CSI.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: Send first capability information, which indicates the ability to support reporting CSI based on the first CSI.

5. The method according to any one of claims 1 to 4, characterized in that, The first CSI also includes fourth information, which indicates a recommended precoding matrix, which is either the first precoding matrix or the second precoding matrix.

6. The method according to any one of claims 1 to 5, characterized in that, The reference signal is the Channel State Information Reference Signal (CSI-RS).

7. A communication method, characterized in that, include: A reference signal is transmitted, which is used to determine Channel State Information (CSI). Receive a first CSI, the first CSI including first information and at least two of the following CSIs: information for indicating a first channel quality, information for indicating a second channel quality, and second information, wherein the first channel quality corresponds to a first precoding matrix, the second channel quality corresponds to a second precoding matrix, the second information indicates the deviation between the first channel quality and the second channel quality, and the first information is used to indicate the target stream corresponding to the first channel quality and the target stream corresponding to the second channel quality; Downlink data is sent based on the first CSI.

8. The method according to claim 7, characterized in that, The first precoding matrix is ​​determined based on the conjugate transpose of the downlink channel matrix, and the second precoding matrix is ​​determined based on the right singular matrix obtained by Singular Value Decomposition (SVD) of the downlink channel matrix.

9. The method according to claim 8, characterized in that, The transmission of downlink data based on the first CSI includes: The downlink data is transmitted based on the first precoding matrix and the target modulation and coding strategy (MCS). The target MCS is related to the deviation.

10. The method according to any one of claims 7 to 9, characterized in that, The method further includes: Send a third message, which indicates whether to report a CSI based on the first CSI.

11. The method according to any one of claims 7 to 10, characterized in that, The method further includes: Receive first capability information, which indicates the capability to support reporting CSI based on the first CSI.

12. The method according to any one of claims 7 to 11, characterized in that, The first CSI also includes fourth information, which indicates a recommended precoding matrix, which is either the first precoding matrix or the second precoding matrix.

13. The method according to any one of claims 7 to 12, characterized in that, The reference signal is the Channel State Information Reference Signal (CSI-RS).

14. A communication method, characterized in that, include: Receive fifth information, which is used to instruct the reporting of second channel state information (CSI), the second CSI including precoding matrix indication (PMI) and channel quality indication (CQI); Send a third CSI, which includes a first indication information, a second indication information, and the CQI. The first indication information is used to indicate that the PMI should be discarded, and the second indication information is used to indicate the target flow used when determining the CQI.

15. The method according to claim 14, characterized in that, The sending of the third CSI includes: If it is determined that the channel stability condition is met, the third CSI is sent.

16. The method according to claim 15, characterized in that, The conditions for channel stability include one or more of the following: the reference signal received power (RSRP) is greater than a first threshold, and the terminal's moving speed is less than or equal to a second threshold.

17. The method according to any one of claims 14 to 16, characterized in that, The method further includes: Receive a sixth message, which indicates whether to report a CSI based on the third CSI.

18. The method according to any one of claims 14 to 17, characterized in that, The method further includes: Send a second capability information, which indicates the ability to support CSI reporting based on the third CSI.

19. The method according to any one of claims 15 to 18, characterized in that, The method further includes: If it is determined that the channel stability condition is not met, the second CSI is sent.

20. A communication method, characterized in that, include: Send a fifth message, which is used to instruct the terminal to report a second channel state information (CSI), the second CSI including a precoding matrix indicator (PMI) and a channel quality indicator (CQI); Receive a third CSI, which includes a first indication information, a second indication information, and the CQI. The first indication information is used to indicate that the PMI should be discarded, and the second indication information is used to indicate the target flow used by the network device when determining the CQI.

21. The method according to claim 20, characterized in that, The method further includes: Send a sixth message, which indicates whether to report a CSI based on the third CSI.

22. The method according to claim 20 or 21, characterized in that, The method further includes: Receive second capability information, which indicates the capability to support CSI reporting based on the third CSI.

23. The method according to any one of claims 20 to 22, characterized in that, The method further includes: Receive the second CSI.

24. A communication device, characterized in that, It includes a module for performing the method as described in any one of claims 1 to 6; or, it includes a module for performing the method as described in any one of claims 7 to 13; or, it includes a module for performing the method as described in any one of claims 14 to 19; or, it includes a module for performing the method as described in any one of claims 20 to 23.

25. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store a program or instructions that, when executed, cause the method of any one of claims 1 to 6 to be implemented; or cause the method of any one of claims 7 to 13 to be implemented; or cause the method of any one of claims 14 to 19 to be implemented; or cause the method of any one of claims 20 to 23 to be implemented.

26. A computer program product, characterized in that, The computer program product includes a computer program that, when run, causes the method as described in any one of claims 1 to 6 to be implemented; or causes the method as described in any one of claims 7 to 13 to be implemented; or causes the method as described in any one of claims 14 to 19 to be implemented; or causes the method as described in any one of claims 20 to 23 to be implemented.

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