Communication method and apparatus for feeding back precoding matrix

Abstract

A communication method and apparatus for feeding back a precoding matrix, applicable to the technical field of communications. The method comprises: a first apparatus receives at least one reference signal, the at least one reference signal being carried by a first beam group, the at least one reference signal being used for determining a first precoding matrix, the first precoding matrix being a precoding matrix corresponding to a channel under a second beam group, and the second beam group being an oversampled beam group corresponding to the first beam group; and the first apparatus sends first information, the first information being used for indicating the second beam group and the first precoding matrix. The method can reduce the feedback overhead of a precoding matrix, and / or reduce the time overhead for feeding back a precoding matrix.

Description

A communication method and apparatus for feedback precoding matrices

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411865570.7, filed on December 16, 2024, entitled "A Communication Method and Apparatus for Feedback Precoding Matrix", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a communication method and apparatus for feedback precoding matrices. Background Technology

[0004] Multiple-input multiple-output (MIMO) technology is a key technology in wireless communication, capable of meeting the demands of high-speed transmission. This technology can utilize spatial resources to enable signals to achieve array gain, multiplexing and diversity gain, and interference cancellation gain in space without increasing system bandwidth, thereby improving the capacity and spectral efficiency of the communication system.

[0005] In MIMO technology, the receiving device can feed back a precoding matrix determined by the receiving device to the transmitting device based on the received reference signal. How to improve the feedback method of the precoding matrix requires further discussion. Summary of the Invention

[0006] This application provides a communication method and apparatus for improving the feedback method of precoding matrices, for example, reducing the feedback overhead of precoding matrices and / or reducing the time overhead of feeding back precoding matrices.

[0007] In a first aspect, embodiments of this application provide a communication method that can be applied to a first device. The first device may be a terminal, or a device within the terminal (e.g., a module, a communication module, a circuit or chip responsible for communication functions (such as a modem chip, also known as a baseband chip, or a system-on-chip (SoC) chip or system-in-package (SIP) chip containing a modem core), a chip system, or a processor), or a logical node, logical module, or software capable of implementing all or part of the terminal's functions.

[0008] The method may include: a first device receiving at least one reference signal, the at least one reference signal being carried by a first beam group, the at least one reference signal being used to determine a first precoding matrix, the first precoding matrix being a precoding matrix corresponding to a channel under a second beam group, the second beam group being a set of oversampled beam groups corresponding to the first beam group. The first device transmitting first information, the first information being used to indicate: the second beam group and / or the first precoding matrix.

[0009] For example, at least one reference signal includes at least one channel state information reference signal (CSI-RS).

[0010] Using this method, when receiving a reference signal through the first beam group, the first device can feed back the precoding matrix corresponding to the channel under the second beam group. The second beam group can be an oversampled beam group of the first beam group. Thus, if the path angle corresponding to the reference signal does not perfectly correspond to the beams in the first beam group, the first device can improve the correspondence between the path angle of the reference signal and the beams in the beam group by selecting a suitable second beam group, reducing the number of beams in the beam group corresponding to the path angle of the reference signal. This reduces the number of beams indicated by the first precoding matrix, thereby reducing the feedback overhead of the precoding matrix.

[0011] Furthermore, in this method, the first device can determine the precoding matrix corresponding to the channel under the second beam group based on the reference signal carried by the first beam group. In this way, the first device can receive the reference signal without using beams outside the first beam group, thereby reducing the time for the first device to receive the reference signal, and further reducing the time overhead of the first device in determining and feeding back the precoding matrix based on the received reference signal.

[0012] Secondly, embodiments of this application provide a communication method that can be applied to a second device. The second device may be an access network device, or a device within the access network device (e.g., a module, communication module, circuit or chip responsible for communication functions (such as a modem chip, or a SoC chip or SIP chip containing a modem core), chip system, or processor), or a logical node, logical module, or software capable of implementing all or part of the functions of the access network device.

[0013] The method may include: a second device transmitting at least one reference signal, the at least one reference signal being carried by a first beam group, the at least one reference signal being used to determine a first precoding matrix, the first precoding matrix being a precoding matrix corresponding to a channel under a second beam group, the second beam group being a set of oversampled beam groups corresponding to the first beam group. The second device receiving first information, the first information being used to indicate: the second beam group and / or the first precoding matrix.

[0014] For example, at least one reference signal includes at least one CSI-RS.

[0015] Using this method, when a reference signal is transmitted through the first beam group, the second device can receive first information. This first information is used to feed back the precoding matrix corresponding to the channel under the second beam group. The second beam group can be an oversampled beam group of the first beam group. Thus, if the path angle corresponding to the reference signal does not perfectly correspond to the beams in the first beam group, the first device can improve the correspondence between the path angle of the reference signal and the beams in the beam group by selecting a suitable second beam group. This reduces the number of beams in the beam group corresponding to the path angle of the reference signal, thereby reducing the number of beams indicated by the first precoding matrix and consequently reducing the feedback overhead of the precoding matrix.

[0016] Furthermore, in this method, the precoding matrix corresponding to the channel under the second beam group is determined based on the reference signal carried by the first beam group. This allows the second device to transmit the reference signal without using beams outside the first beam group, thereby reducing the time the first device takes to receive the reference signal, and consequently reducing the time overhead of the first device in determining and feeding back the precoding matrix based on the received reference signal.

[0017] Based on the first or second aspect, in one possible design, at least one reference signal is used to determine a first precoding matrix, comprising: at least one reference signal being used to determine a channel under a first beam group; the channel under the first beam group being used to determine an antenna domain channel; the antenna domain channel being used to determine a channel under a second beam group; and the channel under the second beam group being used to determine the first precoding matrix. Accordingly, a first device determines a channel under the first beam group based on the at least one reference signal; the first device determines an antenna domain channel based on the channel under the first beam group, and determines a channel under the second beam group based on the antenna domain channel; and the first device determines the first precoding matrix based on the channel under the second beam group.

[0018] With this design, the first device can accurately determine the precoding matrix corresponding to the channel under the second beam group based on at least one reference signal carried by the first beam group.

[0019] Based on the first or second aspect, in one possible design, the second beam group and the first precoding matrix are used to determine the second precoding matrix; correspondingly, the second device can determine the second precoding matrix according to the second beam group and the first precoding matrix. The second precoding matrix is ​​used by the second device to transmit data, and the second precoding matrix is ​​the precoding matrix corresponding to the channel under the first beam group; correspondingly, the second device can transmit data according to the second precoding matrix.

[0020] Optionally, the weight matrix, the first precoding matrix, and the second precoding matrix corresponding to the second beam group satisfy the following formula; correspondingly, the second device can determine the second precoding matrix based on the weight matrix corresponding to the second beam group, the first precoding matrix, and the following formula:

[0021] Among them, W (2) This is the second precoding matrix. F is the conjugate transpose of the weight matrix corresponding to the first beam group. i W is the weight matrix corresponding to the second beam group. (1) This is the first precoding matrix.

[0022] For example, the first precoding matrix satisfies one of the following formulas:

[0023] or

[0024] Among them, W f As the frequency domain basis, W t For time domain basis;

[0025] W1 is the identity matrix. It is a sparse matrix. The non-zero elements in W1 are feedback parameters; or, W1 includes a subset of columns from the identity matrix. This is the feedback parameter matrix.

[0026] With this design, the second device can accurately determine the second precoding matrix used for transmitting data based on the second beam group and the first precoding matrix.

[0027] Based on the first or second aspect, in one possible design, the method further includes: a second device transmitting second information; and correspondingly, a first device receiving the second information. The second information can be used to indicate a first beam group. With this design, the first device can accurately determine the first beam group based on the second information. Furthermore, in this design, the second information can be transmitted from the second device to the first device, thus allowing the second device to flexibly configure beams belonging to the first beam group.

[0028] Based on the first or second aspect, in one possible design, the first beam group includes at least one beam, and the second information is used to indicate the first beam group, including at least one of the following:

[0029] 1. The second information includes an index of each beam in at least one beam group. In this manner, the first device can accurately determine the first beam group based on the second information. Furthermore, in this method, the second information can indicate the first beam group through the index of each beam in the first beam group, thus allowing the second device to flexibly configure beams belonging to the first beam group.

[0030] 2. The second information includes a first bitmap, which is used to indicate at least one beam. In this manner, the first device can accurately determine the first beam group based on the second information. Furthermore, in this method, the second information can indicate the first beam group through the first bitmap, thus allowing the second information to indicate whether one or more beams belong to the first beam group with a single bit, thereby saving signaling overhead.

[0031] 3. The second information includes the index of the first beam group. In this manner, the first device can accurately determine the first beam group based on the second information. Furthermore, in this method, the second information can indicate the first beam group through its index, thus eliminating the need for the second device to send the index of each beam in the first beam group to the first device, thereby saving signaling overhead.

[0032] Based on the first or second aspect, in one possible design, the method further includes: a second device transmitting third information; correspondingly, a first device receiving the third information. The third information is used to indicate the codebook type of the feedback precoding matrix. If the third information indicates that the codebook type of the feedback precoding matrix is ​​a first port selection codebook type, and the codebook of the first port selection codebook type is used to determine the precoding matrix corresponding to the channel under the second beamgroup, the first device transmits the first information; correspondingly, the second device receives the first information. With this design, the first device can accurately determine the codebook type of the feedback precoding matrix based on the third information.

[0033] Based on the first or second aspect, in one possible design, the first information is used to indicate the second beam group, including: the first information includes oversampling parameters corresponding to the second beam group, the oversampling parameters being used to indicate the second beam group. With this design, the first device can accurately determine the indication of the second beam group using the first information.

[0034] Based on the first or second aspect, in one possible design, the method further includes: a second device transmitting fourth information; and correspondingly, a first device receiving the fourth information. The fourth information is used to indicate the number of oversampled beamgroups corresponding to the first beamgroup. With this design, the first device can accurately determine the oversampled beamgroups corresponding to the first beamgroup based on the fourth information.

[0035] Thirdly, embodiments of this application provide a communication method that can be applied to a first device. The first device may be a terminal, or a device within the terminal (e.g., a module, a communication module, a circuit or chip responsible for communication functions (such as a modem chip, or a SoC chip or SIP chip containing a modem core), a chip system, or a processor), or a logical node, logical module, or software capable of implementing all or part of the terminal functions.

[0036] The method may include: a first device receiving at least one reference signal, the at least one reference signal being carried by a first beam group, the at least one reference signal being used to determine a channel under a second beam group, the second beam group being a set of oversampled beam groups corresponding to the first beam group. The first device transmitting seventh information, the seventh information being used to indicate: the second beam group and / or the channel under the second beam group.

[0037] For example, at least one reference signal includes at least one CSI-RS.

[0038] Using this method, when receiving a reference signal through the first beam group, the first device can feed back the channel under the second beam group, which can be an oversampled beam group of the first beam group. Thus, if the path angle corresponding to the reference signal does not perfectly correspond to the beams in the first beam group, the first device can improve the correspondence between the path angle of the reference signal and the beams in the beam group by selecting a suitable second beam group, reducing the number of beams in the beam group corresponding to the path angle of the reference signal. This reduces the number of beams indicating the channel under the second beam group, thereby reducing the feedback overhead of the channel under the second beam group.

[0039] Furthermore, in this method, the first device can determine the channel under the second beam group based on the reference signal carried by the first beam group. In this way, the first device can receive the reference signal without using beams outside the first beam group, thereby reducing the time for the first device to receive the reference signal, and further reducing the time overhead of the first device determining and feeding back the channel under the second beam group based on the received reference signal.

[0040] Fourthly, embodiments of this application provide a communication method that can be applied to a second device. The second device may be an access network device, or a device within the access network device (e.g., a module, communication module, circuit or chip responsible for communication functions (such as a modem chip, or a SoC chip or SIP chip containing a modem core), chip system, or processor), or a logical node, logical module, or software capable of implementing all or part of the functions of the access network device.

[0041] The method may include: a second device transmitting at least one reference signal, the at least one reference signal being carried by a first beam group, the at least one reference signal being used to determine a channel under a second beam group, the second beam group being a set of oversampled beam groups corresponding to the first beam group. The second device receiving seventh information, the seventh information being used to indicate: the second beam group and / or the channel under the second beam group.

[0042] For example, at least one reference signal includes at least one CSI-RS.

[0043] Using this method, when a reference signal is transmitted through the first beam group, the second device can receive seventh information. This seventh information is used to provide feedback on the channel under the second beam group, which can be an oversampled beam group of the first beam group. Thus, if the path angle corresponding to the reference signal does not perfectly correspond to the beams in the first beam group, the first device can improve the correspondence between the path angle of the reference signal and the beams in the beam group by selecting a suitable second beam group. This reduces the number of beams in the beam group corresponding to the path angle of the reference signal, thereby reducing the number of beams indicating the channel under the second beam group and consequently reducing the feedback overhead of the channel under the second beam group.

[0044] Furthermore, in this method, the channel under the second beam group is determined based on the reference signal carried by the first beam group. This allows the second device to transmit the reference signal without using beams outside the first beam group, thereby reducing the time the first device takes to receive the reference signal. This, in turn, reduces the time overhead for the first device to determine and feed back the channel under the second beam group based on the received reference signal.

[0045] Based on the third or fourth aspect, in one possible design, at least one reference signal is used to determine the channel under the second beam group, including: at least one reference signal is used to determine the channel under the first beam group, the channel under the first beam group is used to determine the antenna domain channel, and the antenna domain channel is used to determine the channel under the second beam group. Accordingly, the first device determines the channel under the first beam group based on the at least one reference signal; the first device determines the antenna domain channel based on the channel under the first beam group, and determines the channel under the second beam group based on the antenna domain channel.

[0046] With this design, the first device can accurately determine the channel under the second beam group based on at least one reference signal carried by the first beam group.

[0047] Based on the third or fourth aspect, in one possible design, the second beam group and the channel under the second beam group are used to determine the second precoding matrix; correspondingly, the second device can determine the second precoding matrix based on the second beam group and the channel under the second beam group. The second precoding matrix is ​​used by the second device to transmit data, and the second precoding matrix is ​​the precoding matrix corresponding to the channel under the first beam group; correspondingly, the second device can transmit data based on the second precoding matrix.

[0048] Optionally, the channel under the second beam group can be used to determine the first precoding matrix. The first precoding matrix is ​​the precoding matrix corresponding to the channel under the second beam group. The weight matrix, the first precoding matrix, and the second precoding matrix corresponding to the second beam group satisfy the following formula. Accordingly, the second device can determine the first precoding matrix based on the channel under the second beam group, and determine the second precoding matrix based on the weight matrix, the first precoding matrix, and the following formula:

[0049] Among them, W (2) This is the second precoding matrix. F is the conjugate transpose of the weight matrix corresponding to the first beam group. i W is the weight matrix corresponding to the second beam group. (1) This is the first precoding matrix.

[0050] For example, the first precoding matrix satisfies one of the following formulas:

[0051] or

[0052] Among them, W f As the frequency domain basis, W t For time domain basis;

[0053] W1 is the identity matrix. It is a sparse matrix. The non-zero elements in W1 are feedback parameters; or, W1 includes a subset of columns from the identity matrix. This is the feedback parameter matrix.

[0054] With this design, the second device can accurately determine the second precoding matrix for transmitting data based on the second beam group and the channel under the second beam group.

[0055] Based on the third or fourth aspect, in one possible design, the method further includes: a second device transmitting second information; and correspondingly, a first device receiving the second information. The second information can be used to indicate a first beam group. With this design, the first device can accurately determine the first beam group based on the second information. Furthermore, in this design, the second information can be transmitted from the second device to the first device, thus allowing the second device to flexibly configure beams belonging to the first beam group.

[0056] Based on the third or fourth aspect, in one possible design, the first beam group includes at least one beam, and the second information is used to indicate the first beam group, including at least one of the following:

[0057] 1. The second information includes an index of each beam in at least one beam group. In this manner, the first device can accurately determine the first beam group based on the second information. Furthermore, in this method, the second information can indicate the first beam group through the index of each beam in the first beam group, thus allowing the second device to flexibly configure beams belonging to the first beam group.

[0058] 2. The second information includes a first bitmap, which is used to indicate at least one beam. In this manner, the first device can accurately determine the first beam group based on the second information. Furthermore, in this method, the second information can indicate the first beam group through the first bitmap, thus allowing the second information to indicate whether one or more beams belong to the first beam group with a single bit, thereby saving signaling overhead.

[0059] 3. The second information includes the index of the first beam group. In this manner, the first device can accurately determine the first beam group based on the second information. Furthermore, in this method, the second information can indicate the first beam group through its index, thus eliminating the need for the second device to send the index of each beam in the first beam group to the first device, thereby saving signaling overhead.

[0060] Based on the third or fourth aspect, in one possible design, the method further includes: a second device transmitting third information; correspondingly, a first device receiving the third information. The third information is used to indicate the codebook type of the feedback precoding matrix. If the third information indicates that the codebook type of the feedback precoding matrix is ​​a first port selection codebook type, and the codebook of the first port selection codebook type is used to determine the precoding matrix corresponding to the channel under the second beam group, the first device transmits seventh information; correspondingly, the second device receives the seventh information. Through this design, the first device can accurately determine the codebook type of the feedback precoding matrix based on the third information.

[0061] Based on the third or fourth aspect, in one possible design, the seventh information is used to indicate the second beam group, including: the seventh information includes oversampling parameters corresponding to the second beam group, the oversampling parameters being used to indicate the second beam group. With this design, the first device can accurately determine the indication of the second beam group through the seventh information.

[0062] Based on the third or fourth aspect, in one possible design, the method further includes: a second device transmitting fourth information; and correspondingly, a first device receiving the fourth information. The fourth information is used to indicate the number of oversampled beamgroups corresponding to the first beamgroup. With this design, the first device can accurately determine the oversampled beamgroups corresponding to the first beamgroup based on the fourth information.

[0063] Fifthly, this application provides a communication device. In some examples, the communication device can be a terminal, or a device within a terminal (e.g., a module, communication module, circuit or chip responsible for communication functions (such as a modem chip, or a SoC chip or SIP chip containing a modem core), chip system, or processor), or a logical node, logical module, or software capable of implementing all or part of the terminal's functions. The communication device has the functions to implement the first or third aspects described above. In other examples, the communication device can be an access network device, or a device within an access network device (e.g., a module, communication module, circuit or chip responsible for communication functions (such as a modem chip, or a SoC chip or SIP chip containing a modem core), chip system, or processor), or a logical node, logical module, or software capable of implementing all or part of the access network device's functions. The communication device has the functions to implement the second or fourth aspects described above.

[0064] In one possible design, the communication device includes modules, units, or means that perform the operations involved in any of the first to fourth aspects described above. These modules, units, or means can be implemented in software, hardware, or a combination of both. For example, the communication device includes an interface unit and a processing unit. The interface unit can be used to send and receive signals to enable communication between the communication device and other devices; the processing unit can be used to perform some internal operations of the communication device. The functions performed by the processing unit and the interface unit can correspond to the operations involved in any of the first to fourth aspects described above.

[0065] In one possible design, the communication device includes a processor. The processor is capable of executing computer programs or instructions, for example, executing computer programs or instructions stored in memory. When the computer program or instructions are executed, the communication device performs the methods in any of the possible designs described in any of the first to fourth aspects.

[0066] Optionally, the processor is coupled to the memory via an interface, which is either a memory built into the communication device or an external memory connected to the communication device.

[0067] In one possible design, the communication device includes a processor and an interface circuit, wherein the processor is used to communicate with other devices through the interface circuit and to perform the methods in any of the possible designs in any of the first to fourth aspects described above.

[0068] Sixthly, this application provides a communication system that may include a first device and a second device. The first device may execute the communication method provided in the first aspect, and the second device may execute the communication method provided in the second aspect; or, the first device may execute the communication method provided in the third aspect, and the second device may execute the communication method provided in the fourth aspect.

[0069] In some possible designs, the first device is a terminal and the second device is an access network device.

[0070] In a seventh aspect, this application provides a computer-readable storage medium storing a computer program or instructions, wherein when the computer program or instructions are executed, a method in any possible design of any of the first to fourth aspects described above is implemented.

[0071] Eighthly, this application provides a computer program product comprising computer program code, wherein when the computer program code is run, a method in any possible design of any of the first to fourth aspects described above is implemented.

[0072] Ninthly, this application provides a chip that may include at least one processor for executing computer programs or instructions in memory to implement the methods in any possible design of any of the first to fourth aspects described above.

[0073] The technical effects that can be achieved by any of the fifth to ninth aspects mentioned above can be described with reference to the technical effects that can be achieved by any of the possible designs in the first to fourth aspects mentioned above. The repetitions will not be discussed. Attached Figure Description

[0074] Figures 1A and 1B are architectural diagrams of several communication systems provided in the embodiments of this application;

[0075] Figure 1C is an architecture diagram of an open RAN (O-RAN or ORAN) device provided in an embodiment of this application;

[0076] Figures 2A to 2C are schematic diagrams of several beamforming methods provided in the embodiments of this application;

[0077] Figure 3 is a flowchart of a method for measuring channel state information (CSI) provided in an embodiment of this application;

[0078] Figure 4 is a schematic diagram of several application scenarios provided in the embodiments of this application;

[0079] Figure 5 is a flowchart of a communication method provided in an embodiment of this application;

[0080] Figures 6A to 6C are schematic diagrams of several oversampling beam groups provided in the embodiments of this application;

[0081] Figure 7A is a schematic diagram of a channel transformation provided in an embodiment of this application;

[0082] Figure 7B is a schematic diagram of the channel under the beam group and its corresponding precoding matrix provided in the embodiment of this application;

[0083] Figure 7C is a schematic diagram of the beam group and the precoding matrix corresponding to the channel under the beam group provided in the embodiment of this application;

[0084] Figure 8 is a flowchart of another communication method provided in an embodiment of this application;

[0085] Figures 9 to 12 are structural diagrams of several communication devices provided in the embodiments of this application. Detailed Implementation

[0086] The technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings. The technical solutions in the embodiments of this application can be applied to various communication systems, such as wireless local area networks (WLANs), wireless fidelity (Wi-Fi or WiFi) systems, fourth-generation (4G) mobile communication systems (such as long-term evolution (LTE) systems), fifth-generation (5G) mobile communication systems (such as new radio (NR) systems), or future communication systems. The methods provided in the embodiments of this application can be applied to terrestrial network communication systems or non-terrestrial network (NTN) communication systems. NTN communication systems can be, for example, satellite communication systems, and may also include unmanned aerial vehicles (UAVs), high-altitude platform stations (HAPS), and other aerial access network equipment; this application does not limit these aspects.

[0087] This application will present various aspects, embodiments, or features relating to systems that may include multiple devices, components, modules, etc. It should be understood and appreciated that individual systems may include additional devices, components, modules, etc., and / or may not include all devices, components, modules, etc. discussed in conjunction with the accompanying drawings. Furthermore, combinations of these approaches are also possible.

[0088] Figure 1A illustrates a schematic diagram of a communication system provided in an embodiment of this application. As shown in Figure 1A, the communication system 10 includes a radio access network (RAN) 100 and a core network (CN) 200. Optionally, the communication system 10 may also include the Internet 300.

[0089] RAN 100 includes at least one RAN node (110a and 110b in Figure 1A, collectively referred to as 110) and at least one terminal (120a-120j in Figure 1A, collectively referred to as 120). RAN 100 may also include other RAN nodes, such as wireless relay equipment and / or wireless backhaul equipment (not shown in Figure 1A). Terminal 120 is wirelessly connected to RAN node 110. RAN node 110 is wirelessly or wired connected to core network 200. The core network equipment in core network 200 and RAN node 110 in RAN 100 can be different physical devices, or they can be the same physical device integrating core network logical functions and wireless access network logical functions.

[0090] RAN 100 can be a cellular system related to the 3rd Generation Partnership Project (3GPP), such as 4G, 5G mobile communication systems, or future-oriented evolution systems. RAN 100 can also be ORAN, cloud radio access network (CRAN), or WiFi system. RAN 100 can also be a communication system that integrates two or more of the above systems.

[0091] RAN node 110, sometimes referred to as RAN entity or access node, constitutes part of the communication system and assists terminals in achieving wireless access. Multiple RAN nodes 110 in communication system 10 can be of the same type or different types. In some scenarios, the roles of RAN node 110 and terminal 120 are relative. For example, network element 120i in Figure 1A can be a helicopter or drone, which can be configured as a mobile base station. For terminals 120j accessing RAN 100 through network element 120i, network element 120i is a base station; however, for base station 110a, network element 120i is a terminal. RAN node 110 and terminal 120 are sometimes both referred to as communication devices. For example, network elements 110a and 110b in Figure 1A can be understood as communication devices with base station functions, and network elements 120a-120j can be understood as communication devices with terminal functions.

[0092] RAN nodes can also be described in different ways, such as access network equipment. Unless otherwise specified in this application, access network equipment will be used as the term.

[0093] Access network equipment can be devices or modules located on the network side of the aforementioned communication system and possessing corresponding communication functions. Access network equipment typically contains communication modules, circuits, or chips that perform the corresponding communication functions. Access network equipment may also be configured with programs or instructions for performing the corresponding communication functions, as well as the corresponding programs or instructions themselves.

[0094] In one possible scenario, access network equipment can be a base station (BS), an evolved NodeB (eNodeB), a transmission point (TP), an access point (AP), a transmission reception point (TRP), a mobile switching center, a next-generation NodeB (gNB), a next-generation base station in a future communication system, or an access node in a WiFi system. Access network equipment can also be a macro base station (as shown in Figure 1A, 110a), a micro base station or indoor station (as shown in Figure 1A, 110b), a relay node or donor node, a radio controller in a CRAN scenario, a satellite, a drone, a balloon, or an aircraft. Optionally, access network equipment can also be a server, wearable device, vehicle, or in-vehicle equipment. For example, in vehicle-to-everything (V2X) technology, the access network equipment can be a roadside unit (RSU). All or part of the functions of the access network device in this application can also be implemented by software functions running on hardware, or by virtualization functions instantiated on a platform (e.g., a cloud platform).

[0095] In another possible scenario, multiple access network devices collaborate to assist the terminal in achieving wireless access, with each device performing a portion of the base station's functions. For example, the access network devices can be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU can be separate entities or included in the same network element, such as a baseband unit (BBU). The RU can be included in radio frequency equipment or radio frequency units, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0096] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called an open CU (O-CU), DU can also be called an open DU (O-DU), CU-CP can also be called an open CU-CP (O-CU-CP), CU-UP can also be called an open CU-UP (O-CU-UP), and RU can also be called an open RU (O-RU). Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0097] A terminal is a device or module that connects to the aforementioned communication system and possesses corresponding communication functions. A terminal can also be called a terminal device, user equipment (UE), mobile station, mobile terminal, wireless terminal device, subscriber unit, subscriber station, mobile station, remote station, user terminal, user agent, or user device, etc. A terminal typically contains communication modules, circuits, or chips that perform the corresponding communication functions. The terminal may also be configured with programs or instructions for performing these communication functions.

[0098] Terminals can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-thing (V2D) communication, machine-type communications (MTC), the Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities. Terminals can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, etc. Wearable devices, also known as wearable smart devices or smart wearable devices, are a general term for devices that utilize wearable technology to intelligently design and develop everyday wearables. Terminals used in vehicles are called in-vehicle terminal devices, which include, for example, transportation vehicles with wireless communication capabilities, communication modules, or on-board units (OBUs).

[0099] For example, a terminal may include a mobile phone (or "cellular" phone), a computer with a mobile terminal device, or a portable, pocket-sized, handheld, or computer-embedded mobile device. For instance, a terminal may be a Personal Communication Service (PCS) phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), or other similar devices. A terminal may also include restricted devices, such as devices with limited power consumption, limited storage capacity, or limited computing power. For example, a terminal may be an information sensing device such as a barcode scanner, radio frequency identification (RFID), a sensor, a global positioning system (GPS), or a laser scanner. The embodiments of this application do not limit the device form of the terminal.

[0100] In this application, core network equipment refers to equipment in the core network that provides service support to terminals. For example, in the case where CN200 is the core network of a future communication system, a 5G core network, or an evolved 5G core network, some examples of core network equipment include: access and mobility management function (AMF) entities, session management function (SMF) entities, user plane function (UPF) entities, policy control function (PCF) entities, etc., which are not listed here. Among them, the AMF entity can be responsible for terminal access management and mobility management; the SMF entity can be responsible for session management, such as user session establishment; the UPF entity can be a user plane functional entity, mainly responsible for connecting to external networks. For example, in the case of CN200 as a 4G core network, some core network devices include: Mobile Management Entity (MME), Home Subscriber Server (HSS), Serving Gateway (S-GW), Policy and Charging Rules Function (PCRF), Public Data Network Gateway (PDN Gateway, P-GW), etc., which will not be listed here. It should be noted that in this application, entities can also be referred to as network elements or functional entities. For example, an AMF entity can also be called an AMF network element or AMF functional entity, and similarly, an SMF entity can also be called an SMF network element or SMF functional entity. The aforementioned core network devices can operate independently or be combined to implement certain control functions. For example, AMF, SMF, and PCF can be combined into a single core network device.

[0101] Figure 1B illustrates an exemplary ORAN system architecture provided in an embodiment of this application. The ORAN system in this embodiment may include components other than those shown in Figure 1B. As shown in Figure 1B, access network devices can communicate with the core network (CN) via a backhaul link and with terminals via an air interface. For example, a BBU in the access network device communicates with the core network via a backhaul link, and an RU in the access network device communicates with at least one terminal via an air interface. The BBU communicates with at least one RU via a fronthaul link; the BBU and RU may or may not be co-located. The BBU includes at least one CU and at least one DU, which can communicate via at least one midhaul link.

[0102] Figure 1C illustrates, exemplarily, a network element function division and protocol layer structure diagram of an ORAN device provided in an embodiment of this application.

[0103] In some possible implementations, the CU is a logical node that carries the radio resource control (RRC) layer, service data adaptation protocol (SDAP) layer, packet data convergence protocol (PDCP) layer, and other control functions of the access network equipment. The CU can connect to network nodes such as the core network through interfaces (e.g., E2 interfaces). Optionally, the CU can have some of the core network's functions. The CU (e.g., the PDCP layer and higher layers of the CU) connects to the DU (e.g., the radio link control (RLC) layer and lower layers of the DU) through interfaces (e.g., the F1 interface). Exemplarily, the F1 interface can provide control plane (C-Plane) and user plane (U-Plane) functions (e.g., interface management, system information management, UE context management, RRC message transmission, etc.). F1AP is the application protocol of the F1 interface, and in some examples, it defines the signaling procedures of F1. The F1 interface supports both the F1 control plane (F1-C) and the F1 user plane (F1-U).

[0104] In some examples, a CU may include CU-CP and CU-UP. CU-CP is a logical node carrying the control plane (PDCP-C) layer, which carries the RRC layer and the Packet Data Convergence Protocol layer, and is used to implement the CU's control plane functions. CU-CP can interact with network elements in the core network used to implement control plane functions. These network elements in the core network can be Access and Mobility Function (AMF) network elements, such as the AMF in a 5G system. CU-UP is a logical node carrying the user plane (PDCP-U) layer, which carries the SDAP layer and the Packet Data Convergence Protocol layer, and is used to implement the CU's user plane functions. CU-UP can interact with network elements in the core network used to implement user plane functions. These network elements in the core network are, for example, the UPF in a 5G system.

[0105] In some possible implementations, the DU is a logical node that carries the RLC layer, the medium access control (MAC) layer, the higher physical layer (Higher PHY) layer, and other functions. In some examples, the DU can control at least one RU. The DU connects to the RU through some interface (e.g., a fronthaul interface). In some examples, the Higher PHY layer includes the physical layer (PHY) processing, such as forward error correction (FEC) encoding and decoding, scrambling, modulation, and demodulation.

[0106] The above configurations of CU and DU are merely examples; the functions of CU and / or DU can be configured as needed. For instance, CU or DU can be configured to have more protocol layer functions, or to have only some protocol layer processing functions. For example, some RLC layer functions and protocol layer functions above the RLC layer can be placed in the CU, while the remaining RLC layer functions and protocol layer functions below the RLC layer can be placed in the DU. Furthermore, the functions of CU or DU can be divided according to service type or other system requirements, such as by latency, placing functions that need to meet low latency requirements in the DU and functions that do not need to meet such latency requirements in the CU.

[0107] In some possible implementations, the RU is a logical node that carries both the lower physical layer (Lower PHY) and radio frequency (RF) processing. In some examples, the RU can be a 3GPP TRP or RRH, or other similar functional entities. In some examples, the Low-PHY includes PHY processing functions such as Fast Fourier Transform (FFT), Inverse Fast Fourier Transform (IFFT), digital beamforming, and filtering. The RU communicates with one or more terminals via a wireless link.

[0108] The DU and RU can be co-located or not. The DU and RU exchange control plane and user plane information via a fronthaul link through a Lower-Layer Split CUS-Plane (LLS-CUS or LLS-C / U / S) interface. LLS-CUS may include a Lower-Layer Split C-Plane (LLS-C) interface providing the control plane (C-Plane) and a Lower-Layer Split U-Plane (LLS-U) interface providing the user plane (U-Plane). In some examples, the control plane refers to real-time control between the DU and RU. The DU and RU exchange management information via a Lower-Layer Split management (LLS-M) interface on the fronthaul link. The management plane (M-Plane) refers to non-real-time management operations between the DU and RU.

[0109] DU and RU can cooperate to implement the functions of the PHY layer. A DU can be connected to one or more RUs. The functions of DU and RU can be configured in various ways depending on the design. For example, a DU can be configured to implement baseband functions, and an RU can be configured to implement mid-RF functions. Another example is that a DU can be configured to implement higher-level functions in the PHY layer, and an RU can be configured to implement lower-level functions in the PHY layer, or both lower-level and RF functions. Higher-level functions in the physical layer can include a portion of the physical layer's functions that are closer to the MAC layer, while lower-level functions in the physical layer can include another portion of the physical layer's functions that are closer to the mid-RF side.

[0110] The communication systems and service scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new service scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0111] The relevant terms used in the embodiments of this application will be explained below. It should be noted that these explanations are for the purpose of making the embodiments of this application easier to understand, and should not be regarded as a limitation on the scope of protection claimed by this application.

[0112] 1. Reference signal (RS):

[0113] Reference signals, also known as pilot signals, are essential in communication systems for transmitting and receiving data, obtaining system synchronization and feedback channel information, and estimating the uplink or downlink channel. Channel estimation refers to the process of reconstructing or recovering the received signal to compensate for signal distortion caused by channel fading and noise fading. It uses known reference signals from both the transmitter and receiver to determine the time and frequency domain variations of the channel. These reference signals, also called reference signals, are distributed across one or more resource elements (REs) in the time-frequency two-dimensional space within orthogonal frequency division multiplexing (OFDM) symbols, and have known amplitude and phase.

[0114] At the physical layer, uplink communication can include the transmission of uplink physical channels and uplink signals. Uplink physical channels include the Physical Random Access Channel (PRACH), Physical Uplink Control Channel (PUCCH), and Physical Uplink Shared Channel (PUSCH), etc. Uplink signals include the Sounding Reference Signal (SRS), the PUCCH Demodulation Reference Signal (PUCCH-DMRS), the PUSCH Demodulation Reference Signal (PUSCH-DMRS), the Demodulation Reference Signal (DMRS), the Phase Tracking Reference Signal (PTRS), and the Positioning Reference Signal (SRS), etc. The Positioning Reference Signal, for example, is the SRS for Positioning or the Positioning SRS.

[0115] At the physical layer, downlink communication can include the transmission of downlink physical channels and downlink signals. Downlink physical channels include the physical broadcast channel (PBCH), physical downlink control channel (PDCCH), physical downlink shared channel (PDSCH), etc. Downlink signals include the primary synchronization signal (PSS) / secondary synchronization signal (SSS), physical downlink control demodulation reference signal (PDCCH-DMRS), physical downlink shared channel demodulation reference signal (PDSCH-DMRS), DMRS, PTRS, CSI-RS, cell reference signal (CRS), tracking reference signal (TRS), positioning reference signal (positioning RS), synchronization signal block (SSB), etc.

[0116] It should be understood that the reference signals listed above are merely examples and should not be construed as limiting this application. This application does not preclude the possibility of defining other reference signals in future agreements to achieve the same or similar functions.

[0117] 2. Beam:

[0118] Mobile communication systems (such as 5G mobile communication systems) can employ high-frequency communication, meaning they use high-frequency signals to transmit data. A major problem with high-frequency communication is that signal energy decreases sharply with transmission distance, resulting in short transmission ranges. To overcome this problem, high-frequency communication uses analog beamforming technology. By weighting the antenna array, the signal energy is concentrated within a small angular range, forming a beam-like signal (called an analog beam, or simply a beam), thereby increasing the transmission distance. Access network equipment and terminals can both use beamforming for transmission.

[0119] In protocols (e.g., NR protocol), beams can be referred to as spatial domain filters, spatial filters, spatial domain parameters, spatial parameters, spatial domain settings, spatial settings, quasi-co-location (QCL) information, QCL assumptions, or QCL indications, etc. Beams can also be represented by transmission configuration indicator state parameters or spatial relation parameters. The English terms for transmission configuration indicator state include transmission configuration indicator state (TCI-state), transmission configuration indication state (TCI-state), and transmission configuration index state (TCI-state), etc. Therefore, in this application, "beam" can be replaced by spatial filter, spatial filter, spatial parameter, spatial parameter, spatial setting, spatial setting, QCL information, QCL assumption, QCL indication, TCI-state (e.g., downlink TCI-state, DL TCI-state, and / or uplink TCI-state, UL TCI-state), or spatial relationship, etc. The above terms are also equivalent to each other. "Beam" can also be replaced with other beam-related terms, which are not limited in this application.

[0120] The beam used to transmit signals can be called a transmission beam (Tx beam), a spatial domain transmission filter, a spatial transmission filter, a spatial domain transmission parameter, a spatial transmission parameter, a spatial domain transmission setting, or a spatial transmission setting.

[0121] The beam used to receive signals can be called a reception beam (Rx beam), a spatial domain reception filter, a spatial reception filter, a spatial domain reception parameter, a spatial reception parameter, a spatial domain reception setting, or a spatial reception setting.

[0122] The transmitting beam can refer to the distribution of signal strength in different directions in space after a signal is transmitted through an antenna, while the receiving beam can refer to the distribution of signal strength in different directions in space of a wireless signal received from an antenna.

[0123] Furthermore, the beam can be a wide beam, a narrow beam, or other types of beam. The beamforming technology can be beamforming technology or other technologies. Beamforming technology can be, for example, digital beamforming technology, analog beamforming technology, or hybrid beamforming technology.

[0124] Beams generally correspond to resources. For example, during beam measurement, access network equipment measures different beams using different resources. The terminal provides feedback on the measured resource quality, allowing the access network equipment to determine the quality of the corresponding beam. During data transmission, beams can also be indicated by their corresponding resources. For instance, a beam can be indicated by at least one of the following resources, or a beam can be replaced by at least one of the following: SSB resource, CSI-RS resource, SRS resource, DMRS resource, or PTRS resource, etc. Specifically, an SSB resource can be used for transmitting SSB; a CSI-RS resource can be used for transmitting CSI-RS; an SRS resource can be used for transmitting SRS; a DMRS resource can be used for transmitting DMRS; and a PTRS resource can be used for transmitting PTRS. Optionally, different beams can be used to transmit the same or different information. The full name of SSB can be Synchronization Signal Block or Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) Block (SS / PBCH block).

[0125] In some implementations, access network devices can indicate the PDSCH beam information of the terminal through the transmission configuration indicator (TCI) field in the downlink control information (DCI). The English terms for transmission configuration indicator (TCI), transmission configuration indication (TCI), or transmission configuration index (TCI) may include these.

[0126] Optionally, multiple beams with the same or similar communication characteristics can be considered as a single beam. A beam may correspond to one or more antenna ports for transmitting data channels, control channels, and detection signals, etc. One or more antenna ports forming a beam can also be considered as a set of antenna ports.

[0127] A beam group may include one or more beams. As mentioned above, a beam may correspond to a resource; therefore, a beam group may be replaced by a resource group or a set of resources. For example, the first beam group in this application may be replaced by a first resource group or a first set of resources; the second beam group in this application may be replaced by a second resource group or a second set of resources; the oversampled beam group in this application may be replaced by an oversampled resource group or a set of oversampled resources. As mentioned above, a beam may correspond to one or more antenna ports; therefore, a beam group may also be replaced by an antenna port set, an antenna port group, or a set of antenna ports. For example, the first beam group in this application may be replaced by a first antenna port set, a first antenna port group, or a first set of antenna ports; the second beam group in this application may be replaced by a first antenna port set, a second antenna port group, or a second set of antenna ports; the oversampled beam group in this application may be replaced by an oversampled antenna port set, an oversampled antenna port group, or a set of oversampled antenna ports.

[0128] 3. Antenna Port:

[0129] An antenna port, often simply called a port, is a logical concept. It can be understood as a virtual transmitting antenna (or antenna array) identified by the receiver, or a spatially distinguishable virtual transmitting antenna (or antenna array). An antenna port generally corresponds to a physical antenna. Each antenna port represents a channel model, which can be derived from a reference signal on the antenna port. Therefore, an antenna port is usually associated with a reference signal, and its meaning can be understood as a transmit / receive interface on the channel through which the reference signal passes. Because antenna ports can be associated with reference signals, each antenna port can be called a port for a reference signal, such as a CSI-RS port, DMRS port, or SRS port. For low frequencies, an antenna port may correspond to one or more antenna elements that jointly transmit the reference signal; the receiver can treat them as a whole without distinguishing between individual elements. For high-frequency systems, an antenna port may correspond to a beam; similarly, the receiver only needs to treat this beam as an interface without distinguishing between individual elements.

[0130] A set of multiple antenna ports can be called a port set. In one approach, multiple digital ports of an access network device are grouped to form multiple port sets. In another approach (e.g., under the HBF architecture), a port set can be multiple digital ports corresponding to the same analog beam, also simply called a port set, or a digital-to-analog port set. Alternatively, a port set can be a set of digital ports corresponding to multiple analog beams, also simply called a port set, or a digital-to-analog port set. Or, multiple digital ports corresponding to an analog beam are divided into multiple subsets, each subset being called a port set, or a digital-to-analog port set.

[0131] In protocols, antenna ports are typically identified by "antenna port" or "port," but they can also be identified by resources (such as CSI-RS resources, SRS resources, DMRS resources, PTRS resources, CRS resources, TRS resources, or SSB resources) or resource groups. In other words, the identifier for an antenna port can be replaced with one of the above-mentioned identifiers; for example, an antenna port can be replaced with an identifier for a resource, a pilot resource, or a reference signal resource.

[0132] A port set may contain one or more antenna ports, typically corresponding to one or more resources. Therefore, a port set can also be replaced with other names, such as resource group, resource set, pilot resource group, pilot resource set, reference signal resource group, reference signal resource set, port group, antenna port group, antenna port set, or antenna port collection, etc., without limitation. In this embodiment, the port set can also be replaced with "port #A to port #B". Here, port #A and port #B can be understood as examples of port indices. The antenna ports indicated by ports #A to #B can be understood as antenna ports indexed from #A to #B, and these antenna port indices are consecutive. In this embodiment, the port set can also be replaced with the index of each antenna port included in the port set. In this case, the antenna ports included in the port set can be consecutive antenna ports or non-consecutive antenna ports.

[0133] 4. Beamforming (BF):

[0134] Beamforming, also known as beamforming, refers to the process of creating a beam, where a beam is the electromagnetic radiation pattern of an antenna system. In multi-antenna systems, beamforming involves adjusting the amplitude or phase of signals on a radio frequency (RF) link to create a directional electromagnetic radiation pattern. Since RF links are divided into digital and analog links, beamforming can be further categorized into digital beamforming, analog beamforming, and hybrid beamforming.

[0135] Before being transmitted through the physical antenna, the signal undergoes preprocessing. This preprocessing alters the amplitude and / or phase of the signal after it is finally modulated onto the carrier wave. The objectives include: eliminating channel-to-channel correlation, ensuring channel independence between antenna ports, and enabling substream data mapped to each antenna port to be transmitted uncorrelatedly in the spatial channel. This results in a narrow beamforming at each antenna port; the narrower the beam, the lower the correlation between beams. In digital links, digital beamforming can be achieved through precoding. The result of precoding is the implementation of digital beamforming and spatial multiplexing.

[0136] The following description uses an access network device as an example of a base station, and refers to Figures 2A to 2C to illustrate beamforming. Generally, in higher frequency communication systems, base stations (and some frequency band terminals) typically use large-scale array antennas (e.g., including 500 to 1000+ antenna elements) to compensate for path loss caused by higher frequency bands and improve coverage through higher array gain. From the perspective of base station implementation, even with large arrays, different array weighting methods (i.e., beamforming methods) are used for different frequency bands and array sizes. Beamforming methods can be categorized into the following three types:

[0137] One approach is digital beamforming (DBF). Figure 2A shows a possible example of a DBF structure. In this structure, each of the multiple transmit / receive channels is connected to a subarray. A transmit / receive channel may include a digital-to-analog converter (DAC); a subarray may include multiple elements, which can be understood as antenna elements. Each transmit / receive channel corresponds to an antenna port, which can be represented as a digital port (or digital channel or digital processing channel). In this structure, each antenna signal is directly converted to the digital domain, and subsequent array weighting is performed in the digital domain, thus achieving beamforming. On the one hand, digital domain signal processing offers the highest degree of freedom, supporting very complex signal processing methods; therefore, for the same array size, the DBF architecture offers the best performance. On the other hand, due to the high power consumption and cost of DACs / analog-to-digital converters (ADCs) (especially under high bandwidth conditions), the cost of DBF is usually the highest for the same array size.

[0138] Another approach is analog beamforming (ABF). Figure 2B shows a possible example of an ABF structure. In this structure, one transmit / receive channel connects to one subarray. One transmit / receive channel may include a DAC; one subarray may include multiple phase shifters and multiple elements, which can be understood as antenna elements. Multiple transmit / receive channels can correspond to one antenna port, which is represented as a digital port (or digital channel or digital processing channel). In this structure, each phase shifter connects to one or a group of antenna elements. By adjusting the phase of the phase shifter corresponding to each antenna element, the radiated signal radiated through the antenna array can be made directional, thereby achieving beamforming. On the one hand, the entire ABF array can correspond to only one DAC / ADC, resulting in low cost and power consumption. On the other hand, the phase shifter design in the analog domain determines the beam direction after beamforming. Since the signal is directly combined in the analog domain, it cannot utilize digital signal processing weighting like DBF. ABF requires pre-configuring the phase shifter settings (i.e., pointing the analog beam towards the target terminal) during transmission and reception. This process needs to be completed through beam scanning during the link establishment phase, introducing additional latency. Generally, once the analog beam is blocked or moved, causing misalignment, the link quality of the system will rapidly decrease or even be interrupted. Therefore, the communication reliability of ABF is not as good as that of DBF.

[0139] Another approach is hybrid beamforming (HBF), which combines ABF and DBF technologies. Figure 2C shows a possible example of an HBF structure. HBF has one or more digital ports supporting digital beamforming. Each digital port corresponds to an ABF subarray, and each ABF subarray contains one or more phase shifters supporting analog beamforming. Figure 2C shows an HBF architecture with 3 digital ports, each corresponding to 2 phase shifters. Compared to ABF, for the same array size, the AMF subarray size corresponding to each digital port is smaller (4 in Figure 2C and 6 in Figure 2B), resulting in a wider beam, better reliability, and lower beam scanning overhead. Generally, the ratio of HBF digital ports to phase shifters varies depending on the frequency and system design requirements. For example, in high-frequency systems, the number of digital ports is small (4-16), and the number of phase shifters corresponding to a single digital port is large (16-32), which is closer to ABF. In low-frequency systems, the number of digital ports is large (32-128), and the number of phase shifters corresponding to a single digital port is even smaller (e.g., 2-10).

[0140] For example, the number of digital ports currently supported by the protocol may include: 2, 4, 8, 12, 16, 24, 32, 48, 64, 96, and 128.

[0141] HBF (Beamforming by Radiation) technology enables coarse-grained beamforming in the digital domain and fine-grained beam adjustment in the analog domain, thus achieving efficient signal transmission. HBF technology can optimize signal directionality and coverage while balancing hardware complexity and power consumption. Because it can effectively focus signal energy and overcome signal attenuation at high frequencies, HBF technology is well-suited for centimeter-wave and millimeter-wave bands.

[0142] Generally, ABF and HBF architectures can include analog beams. When the analog beams are aligned with the communication target, signal quality will be improved. The direction of the analog beams (determined by beam weights) needs to be configured before transmission and reception. For a given terminal, the process of the base station selecting an analog beam is called beam training or beam scanning. Beam scanning typically involves the base station transmitting reference signals using different analog beam weights, and the terminal measuring the reference signals and feeding back the measurement results to assist the base station in determining which beam has the best quality.

[0143] 5. Precoding and codebook:

[0144] In communication systems, the mathematical expression for communication is y = Hx + n, where y is the received signal, H is the MIMO channel, x is the transmitted signal, and n is noise. In communication systems with multiple antennas, signals from multiple transmitting antennas can be superimposed on any one receiving antenna. Therefore, the method of transmitting signals at the transmitting end affects the system performance, and recovering the transmitted signal at the receiving end is often complex. In this context, precoding can reduce system overhead and maximize the system capacity of MIMO, while also reducing the complexity of eliminating inter-channel interference at the receiver. In this case, the mathematical expression is y = HPx + n, where P is the precoding matrix (or vector, or precoder). To simplify implementation complexity, P can be selected from a predefined set of matrices (or vectors), called the codebook. This signal transmission method is also called a codebook-based transmission method. If the transmitting end has all the information of H, then P can be obtained at the transmitting end itself; this signal transmission method is called a non-codebook (NCB) transmission method.

[0145] 6. Precoding Matrix Indicator (PMI):

[0146] The Precoding Matrix (PMI) can be used to indicate the precoding matrix. This precoding matrix can be, for example, a precoding matrix determined by the terminal based on the channel matrix of a single frequency domain unit. This channel matrix can be determined by the terminal through channel estimation or based on channel reciprocity. However, it should be understood that the specific methods by which the terminal determines the precoding matrix are not limited to those described above; specific implementation methods can be found in the protocol, and for the sake of brevity, they will not be listed here.

[0147] For example, the precoding matrix can be obtained by performing singular value decomposition (SVD) on the channel matrix or its covariance matrix, or by performing eigenvalue decomposition (EVD) on the covariance matrix of the channel matrix. It should be understood that the methods for determining the precoding matrix listed above are merely examples and should not constitute any limitation on this application.

[0148] It should be noted that in this application, the access network device can determine the precoding matrix based on feedback from the terminal. For example, the access network device can determine the CSI RS port, the frequency domain discrete Fourier transformation (DFT) vector, and the space-frequency vector combining coefficients for constructing the precoding vector based on feedback from the terminal, and thus determine the precoding matrix corresponding to each frequency domain unit. This precoding matrix can be directly used for downlink data transmission; or it can be processed through some beamforming methods, such as zero forcing (ZF), regularized zero-forcing (RZF), minimum mean-squared error (MMSE), and maximizing the signal-to-leakage-and-noise ratio (SLNR), to obtain the final precoding matrix used for downlink data transmission. This application does not limit this. Unless otherwise specified, the precoding matrix mentioned below refers to the precoding matrix determined based on the method provided in this application.

[0149] It is understandable that the precoding matrix determined by the terminal can be interpreted as the precoding matrix to be fed back. The terminal can indicate the precoding matrix to be fed back through the PMI, so that the access network device can recover the precoding matrix based on the PMI. It is understandable that the precoding matrix recovered by the access network device based on the PMI can be the same as or similar to the precoding matrix to be fed back.

[0150] In downlink channel measurement, the higher the approximation between the precoding matrix determined by the access network equipment based on the PMI and the precoding matrix determined by the terminal, the better the precoding matrix determined by the access network equipment for data transmission can be adapted to the channel state, thus improving the signal reception quality.

[0151] 7. The process of obtaining and reporting CSI:

[0152] The key technology of beamforming is to obtain the channel state between the transmitting and receiving devices, i.e., the channel matrix. This channel state can be used to determine the precoding matrix, thereby realizing beamforming and improving system capacity.

[0153] Among some possible methods, CSI-RS can be used to measure channel state. The method for acquiring and feeding back CSI is described below with reference to Figure 3. As shown in Figure 3, this measurement method may include:

[0154] S301: The access network device sends measurement configuration information to the terminal.

[0155] This measurement configuration information can also be referred to as reference signal and channel information reporting configuration information. This measurement configuration information can be carried in the RRC signaling sent by the access network equipment to the terminal.

[0156] Optionally, measurement configuration information includes resource configuration information and reporting configuration information. Resource configuration information is related to measurement resources and can be used to configure them. In the protocol, these measurement resources can be configured through a three-level structure: resource configuration (resourceConfig or resourceSetting), resource set (resourceSet), and resource (resource). For example, an access network device can configure one or more resource configurations for a terminal. Each resource configuration includes one or more resource sets, and each resource set can include one or more resources. Each resource configuration / resource set / resource includes its own index. Furthermore, each resource configuration / resource set / resource also includes other parameters, such as the resource's period and the signal type corresponding to the resource. Reporting configuration information refers to information related to the reporting of measurement results, which can be configured through reporting configuration (ReportConfig) in the protocol. An access network device can configure one or more reporting configurations for a terminal. Each reporting configuration includes reporting indicators, reporting time and period, reporting format, and other reporting-related information. In addition, the reporting configuration also includes an index of the resource configuration, used to indicate which measurement resources(s) were used to measure the reported results.

[0157] S302: Access network equipment sends CSI-RS to the terminal.

[0158] Optionally, the access network device may send CSI-RS on the resources configured in the resource configuration information.

[0159] S303: The terminal measures the CSI-RS to obtain the CSI.

[0160] For example, the terminal can measure CSI-RS according to one or more of the following parameters indicated by the measurement configuration information to obtain CSI: number of CSI-RS ports, codebook type, or codebook subset limit.

[0161] Optionally, CSI is information used to characterize the channel state and may include at least one of the following: CSI-RS resource indicator (CRI), channel quality indicator (CQI), PMI, rank indicator (RI), layer indicator (LI), reference signal received power (RSRP), signal-to-interference-plus-noise ratio (SINR), etc.

[0162] S304: The terminal sends a CSI to the access network equipment.

[0163] Optionally, CSI can be contained in a CSI report.

[0164] The method shown in Figure 3 is applicable to port selection (PS) codebooks. For PS codebooks, the spatial basis of the precoding matrix can be an identity matrix, or include some columns of the identity matrix. Currently, for PS codebooks, in S302, access network devices can transmit CSI-RS in a weighted manner, which is equivalent to beamforming the CSI-RS. Specifically, assuming the CSI-RS is x′ and the weight matrix is ​​F (also called the outer weight or weighted matrix), the signal transmitted by the antenna port is Fx′. The signal received by the terminal can be expressed as: y = HFx′ + n = H eff x′+n. Where, H eff =HF represents the beam domain channel as seen by the terminal. The beam domain channel can be understood as the channel measured by the terminal under a portion of the beam, where the measured portion (i.e., the measurement space) is determined by the outer weights. In S303, the terminal can determine the beam domain channel H based on... eff Determine the precoding matrix W eff W eff It can indicate at least one beam selected by the terminal and the weight corresponding to each of those at least one beam. Since the beams and antenna ports correspond, therefore, W eff It can also indicate at least one antenna port selected by the terminal and the weight corresponding to each of those at least one antenna port. The precoding matrix W eff It can also be referred to as any of the following: digital beamforming, weights, beam weights, beamforming vectors, or beamforming matrices. The terminal can control W... eff Quantization compression is performed to determine the precoding matrix W corresponding to PMI. pmi This determines the PMI. Due to quantification loss, Wpmi and W eff They may differ. After receiving the PMI, the access network device can, according to W... pmi The signal received by the terminal after transmitting data with a weighted matrix F can be expressed as: y = HFW pmi s+n=H eff W pmi s+n. Where s is the data sent by the access network device.

[0165] 8. PS codebook:

[0166] PS codebooks can be implemented in various ways, such as method 1 or method 2.

[0167] Method 1:

[0168] For the PS codebook, the terminal can be configured with at least one of the following parameters:

[0169] (1) Number of CSI ports: This refers to the number of CSI ports used by the access network device to transmit CSI-RS, and can be configured by the access network device. For example, for a single polarization, the number of CSI ports can be configured by the higher-layer parameter number of ports (nrofPorts). The value of the number of CSI ports includes, but is not limited to, one of 4, 8, 12, 16, 24, 32, 48, 64, 72, 96, 128, 144, 192, 256, or 512.

[0170] (2) The number of beams, L, also known as the number of antenna ports selected by the terminal, can be configured by the access network equipment. For example, the value of L can be configured by the higher-layer parameter, numberOfBeams. L can be related to the number of CSI ports, P. CSI-RS Association. For example, when P CSI-RS When P = 4, L can take the value 2; when P = 4, L can take the value 2. CSI-RS When L > 4, the value of L can be 2, 3, or 4.

[0171] (3) The sampling size (d) can also be referred to as any of the following: sampling period, sampling size, interval factor, or port interval factor. The value of d can be configured by the access network device. For example, the value of d can be configured by the higher-layer parameter port selection sampling size (portSelectionSamplingSize), where d∈{1,2,3,4}. ∈ indicates belonging to; min() indicates taking the minimum value.

[0172] (4) Subband Amplitude can be determined by whether the subband amplitude parameter of the upper layer is true or false.

[0173] Terminal devices do not report rank indicator (RI) values ​​greater than 2.

[0174] When the number of streams υ≤2, each PMI value can correspond to codebook indices i1 and i2; or, the PMI includes codebook indices i1 and i2. Wherein:

[0175] After the terminal selects L antenna ports for a single polarization, it can determine the index i corresponding to those L antenna ports. 1,1 and send i to the access network device 1,1 Access network devices can use index i 1,1 Determine the L antenna ports selected by the terminal for a single polarization, where L is a positive integer. Where:

[0176] i 1,3,l It can be used to determine the strongest coefficient on the l-th (l=1,…,υ) flow, where i 1,3,l ∈{0,1,…,2L-1}.

[0177] For the antenna port selected by the terminal, the terminal can also report the amplitude coefficient indication and / or phase coefficient indication corresponding to the selected antenna port to the access network equipment. That is, the PMI can also include the amplitude coefficient indication and / or phase coefficient indication corresponding to the antenna port selected by the terminal.

[0178] Among them, the amplitude coefficient indicates i 1,4,l i 2,2,l For example:

[0179] For elements in the amplitude coefficient indicator, It can be

[0180] To amplitude coefficient The mapping is shown in Table 1. To amplitude coefficient The mapping is shown in Table 2. Taking two polarizations as an example, the amplitude coefficient can be expressed by the following formula:

[0181] Where l takes the value l = 1, ..., υ.

[0182] Table 1

[0183] It should be noted that Table 1 above is merely an illustrative example and should not be construed as limiting the embodiments of this application. Any reasonable modifications, additions, or deletions to the content of Table 1 that result in new table content are within the protection scope of the embodiments of this application.

[0184] Table 2

[0185] It should be noted that Table 2 above is merely an illustrative example and should not be construed as limiting the embodiments of this application. Any reasonable modifications, additions, or deletions to the content of Table 2 that result in new table content fall within the protection scope of the embodiments of this application.

[0186] Wherein, the phase coefficient indicates i 2,1,l For example: i 2,1,l =[c l,0 ,c l,1 ,…,c l,2L-1 ];

[0187] c l,i This represents the phase coefficient corresponding to the antenna port selected by the terminal, i = 0, 1, ..., 2L-1.

[0188] For example, the precoding matrix indicated by PMI satisfies the following relationship:

[0189] The value of l can be 1 or 2.

[0190] This can indicate the antenna port selected by the terminal, which can be determined based on the i in the PMI. 1,1 Confirmed. For example, It can be a standard vector basis, where the standard vector basis can be a column of the identity matrix. For example, It can include A column vector of elements. The first in One element is 1, and the other elements are 0.

[0191] and The phase corresponding to the antenna port selected for the terminal can be related to the phase coefficient, or it can be 1.

[0192] Method 2:

[0193] For the PS codebook, the terminal can be configured with at least one of the following parameters:

[0194] (1) Number of CSI ports: This refers to the number of CSI ports used by the access network device to transmit CSI-RS, and can be configured by the access network device. For example, for a single polarization, the number of CSI ports can be configured by the higher-layer parameter number of ports (nrofPorts). The value of the number of CSI ports includes, but is not limited to, one of 4, 8, 12, 16, 24, 32, 48, 64, 72, 96, 128, 144, 192, 256, or 512.

[0195] (2) The number of beams, L, also known as the number of antenna ports selected by the terminal, can be configured by the access network equipment. For example, the value of L can be configured by the higher-layer parameter, numberOfBeams. L can be related to the number of CSI ports, P. CSI-RS Association. For example, when P CSI-RS When P = 4, L can take the value 2; when P = 4, L can take the value 2. CSI-RS When L > 4, the value of L can be 2, 3, or 4.

[0196] (3) The sampling size (d) can also be referred to as any of the following: sampling period, sampling size, interval factor, or port interval factor. The value of d can be configured by the access network device. For example, the value of d can be configured by the higher-layer parameter port selection sampling size (portSelectionSamplingSize), where d∈{1,2,3,4}, and d≤L.

[0197] For the PS codebook, the precoding matrix can be represented as: Among them, W1 can be the spatial basis; It is a sparse matrix. The non-zero elements in the data are feedback parameters, or For the feedback parameter matrix; W f It can be a frequency domain basis. For example, the dimension of W is P. CSI-RS ×N3, P CSI-RS N1 represents the number of CSI-RS ports, and N3 represents the number of sub-bands.

[0198] The codebook parameters used in the PS codebook are shown in Table 3 below. Where p υ β is the proportion of the frequency domain basis, υ is the proportion of non-zero elements, and υ is the rank.

[0199] Table 3

[0200] It should be noted that Table 3 above is merely an illustrative example and should not be construed as limiting the embodiments of this application. Any reasonable modifications, additions, or deletions to the content of Table 3 that result in new table content fall within the protection scope of the embodiments of this application.

[0201] In method 2, PMI may include i 1,1 For example, after the terminal selects L antenna ports for a single polarization, it can determine the index i corresponding to those L antenna ports. 1,1 and send i to the access network device 1,1 Access network devices can use index i 1,1 Determine 2L antenna ports, where L is a positive integer.

[0202] against For non-zero elements in the PMI, the terminal needs to report the corresponding amplitude coefficient indication and / or phase coefficient indication. In other words, the PMI needs to include... The amplitude coefficient indicator and / or phase coefficient indicator corresponding to the non-zero elements in the data; for For zero elements, the terminal does not report the corresponding amplitude coefficient indication and / or phase coefficient indication. The terminal can indicate the position of non-zero elements to the access network equipment through a bitmap. The number of non-zero elements in a single layer can be calculated using the following formula:

[0203] Where K0 is the number of non-zero elements in a single layer. This represents the number of frequency domain bases selected for frequency domain compression. It should be understood that the above formula uses two polarizations as an example; the formula should be adjusted accordingly for other values ​​of the number of polarizations.

[0204] When a terminal indicates the position of a non-zero element to the access network device through a bitmap, it can do so via i 1,7,l To provide instructions; in other words, PMI may include i 1,7,l i 1,7,l For non-zero element coefficients, exemplarily:

[0205] For l = 1, ..., υ, such that It is the number of non-zero elements in l = 1, ..., υ. It is the total number of non-zero elements in all streams.

[0206] Amplitude coefficient indicator i 2，4，l Phase coefficient indicator i 2，5，l and non-zero element coefficient indicator i 1，7，l , and n 3，l M v Each codebook is associated with another.

[0207] To amplitude coefficient The mapping is shown in Table 4. To amplitude coefficient The mapping is shown in Table 5. The amplitude coefficient can be expressed by the following formula:

[0208] Where l = 1, ..., υ; f l * ∈{0,1,…,M υ -1} is i 2,4,l The index, and For i 2,5,l The index is used to identify the strongest coefficient of layer l; For i 2,4,l The elements, l = 1, ..., υ; n 3,l The index is Remapping, such as Make the mapped Index f is a pair of f l * The remapping, such as f = (ff l * )mod M υ This makes the index of the strongest coefficient after remapping f. l * =0 (l=1,…,υ). i 2,4,l i 2,5,l i 1,7,l These are bitmaps representing the amplitude coefficients, phase coefficients, and positions of non-zero elements after remapping.

[0209] Table 4

[0210] In Table 4, "Reserved" can refer to a reserved location or an invalid location.

[0211] It should be noted that Table 4 above is merely an illustrative example and should not be construed as limiting the embodiments of this application. Any reasonable modifications, additions, or deletions to the content of Table 4 that result in new table content fall within the protection scope of the embodiments of this application.

[0212] Table 5

[0213] It should be noted that Table 5 above is merely an illustrative example and should not be construed as limiting the embodiments of this application. Any reasonable modifications, additions, or deletions to the content of Table 5 that result in new table content fall within the protection scope of the embodiments of this application.

[0214] For the PS codebook, the precoding matrix of the l-th layer and subband t can be determined by the following relationship:

[0215] The value of l can be one of 1, 2, 3 or 4.

[0216] This can indicate the antenna port selected by the terminal, which can be determined based on the i in the PMI. 1,1 Confirmed. For example, It can be a standard vector basis, where the standard vector basis can be a column of the identity matrix. For example, It can include A column vector of elements. The first in One element is 1, and the other elements are 0.

[0217] and The phase corresponding to the antenna port selected for the terminal can be determined according to the phase coefficient indication in the PMI.

[0218] 9. In this application, the spatial basis may also have other names, such as spatial basis matrix, spatial vector, characteristic matrix or spatial beam group, etc. As long as they have the same function, they are all within the protection scope of this application.

[0219] In this application, the frequency domain basis may also have other names, such as frequency domain basis matrix or frequency domain vector, as long as they have the same function, they are all within the protection scope of this application.

[0220] In this application, the time-domain basis may also have other names, such as time-domain basis matrix or time-domain vector, etc. As long as they have the same function, they are all within the protection scope of this application.

[0221] 10. Sparse Matrices:

[0222] In a matrix, if the number of zero elements is significantly greater than the number of non-zero elements (e.g., the ratio of the number of non-zero elements to the total number of elements in the matrix is ​​less than or equal to 0.05), the matrix is ​​considered sparse. Zero elements can include elements with a value of 0, and non-zero elements can include elements with values ​​other than 0; alternatively, zero elements can include elements with a value of 0 and / or elements with values ​​close to 0, and non-zero elements can include elements with values ​​not close to 0. Optionally, when zero elements include elements close to 0, the values ​​of non-zero elements and zero elements must differ by at least a factor of N, where N is, for example, 20, 50, or 100.

[0223] In a matrix, the larger the ratio of the number of zero elements to the total number of elements, the higher the sparsity of the matrix; the smaller the ratio, the lower the sparsity.

[0224] 11. In this application, "instruction" or "for instruction" may include explicit instruction (or direct instruction) and implicit instruction (or indirect instruction). When describing information for instructing A, it may include whether the information explicitly instructs A or implicitly instructs A, but does not necessarily mean that the information carries A.

[0225] The indication methods involved in the embodiments of this application should be understood to cover various methods that enable the party to be indicated to obtain the information to be indicated. The information to be indicated can be sent as a whole or divided into multiple sub-information and sent separately. Moreover, the sending period and / or sending time of these sub-information can be the same or different, without limitation.

[0226] In the embodiments of this application, "information" can be an explicit indication, that is, a direct indication through signaling, or obtained by combining other rules or parameters with parameters indicated by signaling, or by deduction. It can also be an implicit indication, that is, obtained based on rules or relationships, or based on other parameters, or by deduction. No limitation is imposed.

[0227] 12. In this application, communication between different devices can refer to direct communication between different devices (i.e., without the need for relaying or forwarding by other devices), or communication between different devices through other devices (i.e., requiring relaying or forwarding by other devices), or communication between a functional unit within a device and other devices through another functional unit. For example, "sending information to…(terminal)" can be understood as the destination of the information being the terminal, and may include sending information directly or indirectly to the terminal. "Receiving information from…(terminal)" can be understood as the source of the information being the terminal, and may include receiving information directly or indirectly from the terminal. Information may undergo necessary processing between the source and destination ends, such as format changes, digital-to-analog conversion, amplification, filtering, etc., but the destination end can understand the valid information from the source end. Similar expressions in this application can be understood in a similar way, and will not be elaborated further here.

[0228] 13. In this application, the words "exemplarily," "for example," "for instance," and "example" are used to indicate examples, illustrations, or explanations, and are not intended to limit the scope of protection of this application. It should be understood that the examples in this application may also be implemented in other ways. In this application, "of," "corresponding, relevant," and "corresponding" may sometimes be used interchangeably, and it should be noted that their intended meanings are consistent when their distinction is not emphasized.

[0229] 14. In this application, any two of the programs, instructions and code may be substituted for one another.

[0230] 15. In this application, "*" and "×" represent the meaning of multiplication or multiplication.

[0231] 16. In this application, some characters are in regular font, such as N1, and some characters are in italic font, such as N1. When the same character is used in different fonts, it has the same meaning.

[0232] 17. In this application, the parameters in the formulas can also be represented by other letters, as long as they have the same meaning, they are all within the scope of protection of this application. For example, W in the formula below (2) It can be represented by W.

[0233] 18. In this application, the weight matrix may have other names, such as weighted matrix or outer weight, as long as they have the same meaning, they are all within the scope of protection of this application.

[0234] 19. In this application, an antenna domain channel can be understood as at least one of the following: a multi-antenna channel; or, a channel measured by a terminal when an access network device transmits a reference signal through an antenna. A MIMO channel can be an antenna domain channel. For example, if an access network device transmits information through N1 antennas and a terminal receives information through N2 antennas, then the antenna domain channel can be represented by an N1*N2 matrix, where N1 and N2 are positive integers. Antenna domain channels may also have other names, such as antenna-corresponding channels or antenna channels, without limitation.

[0235] A beam domain channel can be understood as at least one of the following: a channel measured by a terminal under a partial beam, where the measured partial beam (i.e., the measurement space) can be determined by the outer weights; a channel obtained by performing a DFT transform on the antenna domain channel; or, a channel measured by a terminal when the access network equipment transmits a reference signal through a port (e.g., a partial port). A beam domain channel may also have other names, such as beam-corresponding channel, beam channel, port domain channel, port-corresponding channel, or port channel, without limitation.

[0236] Currently, access network devices can transmit CSI-RS in a weighted manner. For example, when transmitting CSI-RS through beams in the first beam group, the access network device can use a weighting matrix F for weighting; correspondingly, the beam domain channel seen by the terminal side can be shown in Figure 4. Each circle in Figure 4 corresponds to a beam in the first beam group; the circles do not overlap, indicating that different beams in the first beam group are orthogonal. The CSI-RS transmitted by the access network device through the first beam group may reach the terminal through at least one path. The pentagrams in Figure 4 can represent the path angle corresponding to the CSI-RS received by the terminal. The terminal can determine the selected beam based on the relationship between the path angle corresponding to the CSI-RS received by the terminal and the beam domain channel, thereby determining the PMI. For example, as shown in Figure 4(a), two pentagrams are located at the centers of two beams. Thus, the terminal can select these two beams and determine the PMI accordingly.

[0237] However, the path angle and beam corresponding to the CSI-RS received by the terminal may not correspond perfectly. For example, as shown in Figure 4(b), the two pentagrams are not located at the centers of the two beams. In this case, the energy of the CSI-RS will leak to nearby beams. If the terminal can only select two beams, since the beams near the pentagrams all have energy, the terminal cannot select a suitable beam based on the CSI-RS carried by the first beam group. The access network equipment needs to send CSI-RS through more beams, thus increasing the time overhead. If the terminal selects a beam only based on the CSI-RS carried by the first beam group, and can select more than two beams, then more than two beams need to be fed back, thus increasing the feedback overhead.

[0238] Based on this, embodiments of this application provide a communication method and apparatus for improving the feedback method of precoding matrices, for example, reducing the feedback overhead of precoding matrices and / or reducing the time overhead of feeding back precoding matrices. The method and apparatus described in this application are based on the same technical concept. Since the principles by which the method and apparatus solve problems are similar, the implementations of the apparatus and method can be referred to each other, and repeated details will not be elaborated further.

[0239] The various communication methods provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings. These methods can be applied to the communication systems shown in FIG1A or FIG1B, but are not limited thereto. The embodiments of this application are described using the interaction between a first device and a second device as an example. The first device may be a terminal, or a device in the terminal (e.g., a module, a communication module, a circuit or chip responsible for communication functions (such as a modem chip, or a SoC chip or SIP chip containing a modem core), a chip system, or a processor), or a logical node, logical module, or software that can implement all or part of the terminal functions. The second device may be an access network device, or a device in the access network device (e.g., a module, a communication module, a circuit or chip responsible for communication functions (such as a modem chip, or a SoC chip or SIP chip containing a modem core), a chip system, or a processor), or a logical node, logical module, or software that can implement all or part of the access network device functions.

[0240] It is understood that in the embodiments of this application, the first device and / or the second device may perform some or all of the steps in the embodiments of this application. These steps or operations are merely examples, and the embodiments of this application may also perform other operations or variations thereof. Furthermore, the steps may be performed in different orders as presented in the embodiments of this application, and it is not necessary to perform all the operations in the embodiments of this application.

[0241] Figure 5 is a flowchart illustrating a communication method provided in an embodiment of this application. As shown in Figure 5, the method may include:

[0242] S501: The second device sends configuration information; correspondingly, the first device receives the configuration information.

[0243] This configuration information can be used to configure the resources carrying the reference signal and / or information related to the reporting of measurement results. For example, this configuration information can be the measurement configuration information in S301, which may include resource configuration information and reporting configuration information. For details, please refer to the description of measurement configuration information in S301; repeated descriptions will not be repeated here.

[0244] In some possible approaches, the configuration information may include second information, such as resource configuration information in the configuration information, which may be used to indicate (or configure) the first beam group; accordingly, the first device may determine the first beam group based on the second information. The first beam group may be a beam group used by the second device to transmit reference signals. For example, the first beam group may be a DFT beam group.

[0245] Optionally, the first beam group can be obtained based on the weight matrix F0. This application does not limit the specific method of obtaining the first beam group based on the weight matrix F0. The first beam group can be obtained based on the weight matrix F0, which can be replaced by the statement that the first beam group is related to (or corresponds to) the weight matrix F0. In some examples, F0 is a square matrix; the first beam group may include all beams in the spatial beam set, and can be called a complete beam group. In other examples, F0 is not a square matrix; the first beam group may include some beams in the spatial beam set, and can be called an incomplete beam group.

[0246] There are multiple ways in which the second information indicates the first beam group, for example, at least one of modes a1 to a3.

[0247] Method a1: The first beam group includes at least one beam; the second information includes the index (or identifier) ​​of each beam in the at least one beam.

[0248] For example, the first beam group includes beams #1 to #10; the second information may include the index (or identifier) ​​of each beam in beams #1 to #10.

[0249] Optionally, the beam index can be one-dimensional or multi-dimensional; in other words, the beam index can be a scalar or a vector. For example, the index of beam #1 is 1, the index of beam #2 is 2, the index of beam #3 is 3, and so on. For another example, the index of beam #1 is (1,1), indicating that beam #1 is the first beam in the horizontal direction and the first beam in the vertical direction. The index of beam #2 is (1,2), indicating that beam #2 is the first beam in the horizontal direction and the second beam in the vertical direction. The index of beam #3 is (2,1), indicating that beam #3 is the second beam in the horizontal direction and the first beam in the vertical direction. The index of beam #4 is (2,2), indicating that beam #4 is the second beam in the horizontal direction and the second beam in the vertical direction.

[0250] In method a1, the first device can accurately determine the first beam group based on the second information. Furthermore, in this method, the second information can indicate the first beam group through the index of each beam in the first beam group, thus allowing the second device to flexibly configure the beams belonging to the first beam group.

[0251] Method a2: The first beam group includes at least one beam; the second information indicates a first bitmap, which is used to indicate the at least one beam.

[0252] The second information indicates the specific manner in which the first bitmap is displayed, and is not limited thereto. For example, the second information may include the first bitmap.

[0253] In some implementations, at least one bit in the first bitmap may correspond to multiple beams. This at least one bit may be some or all of the bits in the first bitmap. Each bit in the at least one bit can be used to indicate whether the beam corresponding to that bit belongs to the at least one beam; in other words, each bit in the at least one bit can be used to indicate whether the beam corresponding to that bit belongs to a first beam group; or, each bit in the at least one bit can be used to indicate whether the first beam group includes the beam corresponding to that bit. For example, if the value of a bit in the at least one bit is a first value (e.g., 1 or 0), then the beam corresponding to that bit belongs to the at least one beam; if the value of a bit in the at least one bit is a second value (e.g., 0 or 1), then the beam corresponding to that bit does not belong to the at least one beam. The first value and the second value are different.

[0254] Optionally, the at least one bit can be arranged in descending order of its corresponding beam index; or, the at least one bit can be arranged in ascending order of its corresponding beam index. The following example illustrates this with the at least one bit arranged in ascending order of its corresponding beam index. For instance, the beam index corresponding to the at least one bit is 0 to 15, with a first value of 1 and a second value of 0. If the value of the first bit map is 1111001011110010, then the indices of the at least one beam include: 0, 1, 2, 3, 6, 8, 9, 10, 11, 14; in other words, the first beam group includes beams with indices of 0, 1, 2, 3, 6, 8, 9, 10, 11, 14.

[0255] In method a2, the first device can accurately determine the first beam group based on the second information. Furthermore, in this method, the second information can indicate the first beam group through a first bitmap, thus allowing the second information to indicate whether one or more beams belong to the first beam group with a single bit, thereby saving signaling overhead.

[0256] Method a3: The second information includes the index of the first beam group.

[0257] Optionally, in mode a3, the first device may have prior knowledge of the correspondence between at least one beam group and at least one index (hereinafter referred to as the first correspondence). The at least one beam group includes a first beam group. The at least one beam group is, for example, at least one DFT beam group. Thus, after receiving the index of the first beam group, the first device can determine the first beam group based on the first correspondence and the index of the first beam group.

[0258] The first correspondence can be pre-defined, for example, as specified by a protocol; or it can be indicated to the first device by another device (e.g., the second device or core network equipment); or it can be determined by the first device. Optionally, if the first correspondence is determined by the first device, the first device can send the indication information of the first correspondence to the second device.

[0259] For example, the first correspondence can be as shown in Table 6. If the beam group index of the first beam group in the second information is 0, then the first device can determine that the first beam group is beam group #a1. If the beam group index of the first beam group in the second information is 1, then the first device can determine that the first beam group is beam group #a2. If the beam group index of the first beam group in the second information is 2, then the first device can determine that the first beam group is beam group #a3.

[0260] Table 6

[0261] It should be noted that Table 6 above is merely an illustrative example and should not be construed as limiting the embodiments of this application. Any reasonable modifications, additions, or deletions to the content of Table 6 that result in new table content fall within the protection scope of the embodiments of this application.

[0262] It should be understood that the first correspondence can also be represented in a form other than a table. For example, the first correspondence can be represented by a mathematical function. For example, y1 = f(x1, x2, ..., x L ), where y1 is the index of the beam group, x1, x2, ..., x L These are the indices of each beam within the beam group. Thus, after receiving the index of the first beam group, the first device can determine the appropriate values ​​based on f(x1,x2,…,x). L The inverse function of f(x1,x2,…,x) determines the index of each beam in the first beam group. L The beam index and its inverse function f can be constructed analytically or algorithmically, without restriction. For details regarding the beam index, please refer to the explanation of beam index in method a1; it will not be repeated here.

[0263] Optionally, the number of beam groups in the at least one beam group may satisfy: C(nrofPorts, nrofPortsUp); the at least one index may include integers from 0 to (C(nrofPorts, nrofPortsUp)-1). Where C(x,y) is a permutation and combination operator, representing the number of combinations of selecting x elements from y distinct elements. For example, C(2,3) = 3. nrofPorts is the number of CSI-RS ports, and nrofPortsUp is the number of antenna ports.

[0264] For example, the second information may be a newly added information element (IE) in the resource configuration information. For instance, the resource configuration information includes:

[0265] The second information can be the selected beam identifier (SelectBeamId) of the newly added network element in the resource configuration information. The value of the second information can be any integer from 0 to (C(nrofPorts,nrofPortsUp)-1).

[0266] In method a3, the first device can accurately determine the first beam group based on the second information. Furthermore, in this method, the second information can indicate the first beam group via an index, thus eliminating the need for the second device to send the index of each beam in the first beam group to the first device, thereby saving signaling overhead.

[0267] In some possible approaches, the configuration information may include third information. For example, the reported configuration information in the configuration information may include third information used to indicate (or configure) the codebook type of the feedback precoding matrix. Accordingly, the first device may determine the codebook type of the feedback precoding matrix based on the third information. This application does not limit the manner in which the third information indicates the codebook type of the feedback precoding matrix.

[0268] The third information may indicate that the codebook type of the feedback precoding matrix is ​​the first port selection codebook type. The codebook of the first port selection codebook type can be used to determine the precoding matrix corresponding to the channel under the second beam group. The second beam group is a set of oversampled beam groups corresponding to the first beam group. Accordingly, if the third information indicates that the codebook type of the feedback precoding matrix is ​​the first port selection codebook type, the first device can determine the precoding matrix corresponding to the channel under the second beam group. The specific method of determination will be explained in S502 below and will not be elaborated here.

[0269] Optionally, the first port can select a codebook type with other names, such as superResolutionPS codebook, etc., without restriction.

[0270] Optionally, the second beam group is an oversampled beam group corresponding to the first beam group. This can be understood as follows: the second beam group is a beam group obtained by shifting the first beam group; or, the second beam group is a beam group obtained by processing the first beam group according to a transformation matrix. Processing the first beam group with the transformation matrix causes it to shift, thus obtaining the second beam group; or, the second beam group and the first beam group correspond to different grouping coefficients (or sampling coefficients), and different grouping coefficients (or sampling coefficients) can correspond to different complete orthogonal bases (or orthogonal complete bases). For example, as shown in Figure 6A, shifting all beams in the first beam group by half a beam along a first direction yields an oversampled beam group, which can be the second beam group. The first direction is, for example, the horizontal direction. As another example, as shown in Figure 6B, shifting all beams in the first beam group by half a beam along a second direction yields an oversampled beam group, which can also be the second beam group. The second direction is, for example, the vertical direction. As shown in Figure 6C, by offsetting all beams in the first beam group by half a beam along the first direction and by half a beam along the second direction, an oversampled beam group can be obtained, which can be the second beam group. Here, the first direction is, for example, the horizontal direction; and the second direction is, for example, the vertical direction.

[0271] In this way, the first device can accurately determine the codebook type of the feedback precoding matrix based on the third information.

[0272] In some possible approaches, the configuration information may include fourth information, for example, resource configuration information in the configuration information may include fourth information. The fourth information indicates the number of M oversampled beamgroups corresponding to the first beamgroup, where M is a positive integer; in other words, the first beamgroup corresponds to M oversampled beamgroups, and the fourth information may indicate M. Accordingly, the first device may determine M based on the fourth information, thereby determining the M oversampled beamgroups corresponding to the first beamgroup.

[0273] For example, if the fourth information indicates that M is 1, then the first device can determine that the M oversampled beam groups corresponding to the first beam group include the oversampled beam groups shown in FIG6A.

[0274] For example, if the fourth information indicates that M is 1, then the first device can determine that the M oversampled beam groups corresponding to the first beam group include the oversampled beam groups shown in FIG6B.

[0275] For example, if the fourth information indicates that M is 1, then the first device can determine that the M oversampled beam groups corresponding to the first beam group include the oversampled beam groups shown in Figure 6C.

[0276] For example, if the fourth information indicates that M is 2, then the first device can determine that the M oversampled beam groups corresponding to the first beam group include the oversampled beam group shown in FIG6A and the oversampled beam group shown in FIG6B.

[0277] For example, if the fourth information indicates that M is 2, then the first device can determine that the M oversampled beam groups corresponding to the first beam group include the oversampled beam group shown in FIG6A and the oversampled beam group shown in FIG6C.

[0278] For example, if the fourth information indicates that M is 2, then the first device can determine that the M oversampled beam groups corresponding to the first beam group include the oversampled beam group shown in FIG6B and the oversampled beam group shown in FIG6C.

[0279] For example, if the fourth information indicates that M is 3, then the first device can determine that the M oversampled beam groups corresponding to the first beam group include: the oversampled beam group shown in FIG6A, the oversampled beam group shown in FIG6B, and the oversampled beam group shown in FIG6C.

[0280] In this way, the first device can accurately determine the oversampled beam group corresponding to the first beam group based on the fourth information.

[0281] Configuration information can be carried in traditional messages or in new messages; there are no restrictions. For example, configuration information can be carried in RRC signaling.

[0282] It should be understood that S501 uses the example of the second, third, and fourth information being carried in the same message for illustration, but it is not limited to this. Any two of the second, third, and fourth information can also be carried in different messages.

[0283] S501 is an optional step.

[0284] S502: The second device sends at least one reference signal; correspondingly, the first device receives at least one reference signal.

[0285] The at least one reference signal may be carried by a first beam group; the at least one reference signal may be used to determine a first precoding matrix, which is the precoding matrix corresponding to the channel under the second beam group. The at least one reference signal may be a conventional reference signal, for example, at least one CSI-RS. The name of the conventional reference signal may change or remain the same during subsequent standard evolution, all within the scope of protection of this application; or, the at least one reference signal may be an evolution of a conventional reference signal, the name of which may change or remain the same, all within the scope of protection of this application; or, the at least one reference signal may be a new reference signal or a reference signal defined in the future.

[0286] Optionally, the at least one reference signal may be carried by the first beam group, which can be understood as any of the following: each of the at least one reference signal may be carried by one beam in the first beam group; or, the second device may transmit one of the at least one reference signal through (or using, or according to) each beam in the first beam group. The second device transmits at least one reference signal; correspondingly, the first device receives at least one reference signal, which may be carried by the first beam group, and can be replaced by: the second device transmitting at least one reference signal through (or using, or according to) the first beam group; correspondingly, the first device receiving at least one reference signal through (or using, or according to) the first beam group.

[0287] In some implementations, the second device can transmit the at least one reference signal via the weight matrix F0 corresponding to the first beam group, thereby enabling the at least one reference signal to be carried by the first beam group. Assuming any one of the at least one reference signal is x″ and the weight matrix is ​​F0, the signal transmitted by the second device through the antenna port is F0x″. The signal received by the first device can be expressed as: y = HF0x″ + n.

[0288] As previously stated, the at least one reference signal can be used to determine the first precoding matrix; correspondingly, the first device can determine the first precoding matrix based on the at least one reference signal.

[0289] In some possible configurations, the at least one reference signal is used to determine the channel under a first beam group, the channel under the first beam group is used to determine the antenna domain channel, the antenna domain channel is used to determine the channel under a second beam group, and the channel under the second beam group is used to determine the first precoding matrix. Accordingly, the first device can perform steps A1 to A3:

[0290] Step A1: The first device determines the channel under the first beam group based on the at least one reference signal.

[0291] This application does not restrict the specific implementation of step A1; for example, it can be determined in a manner specified in the agreement.

[0292] For example, for the scenario shown in Figure 4(b), the channel under the first beam group can be the beam domain channel under the first beam group shown in Figure 7A.

[0293] Step A2: The first device determines the antenna domain channel based on the channel under the first beam group, and determines the channel under the second beam group based on the antenna domain channel.

[0294] The channel corresponding to the first beam group can be represented as H×F0, where H can be a MIMO channel and F0 is the weight matrix corresponding to the first beam group. The first device can be based on... Transform the channel under the first beam group into an antenna domain channel; and according to... The antenna domain channel is transformed into a channel under the second beam group. Wherein, F is the conjugate transpose of F0, F i This is the weight matrix corresponding to the second beam group.

[0295] For example, for the scenario shown in Figure 4(b), if the second beam group is the oversampled beam group shown in Figure 6C, then the channel under the second beam group can be the beam domain channel under the second beam group shown in Figure 7A.

[0296] Step A3: The first device determines the first precoding matrix based on the channel under the second beam group.

[0297] Optionally, in step A3, the first device may Using the spatial basis, the first precoding matrix is ​​determined based on the channel under the second beam group. Here, W1 is the identity matrix; or, W1 includes a subset of columns from the identity matrix.

[0298] Taking Figure 7A as an example, the pentagrams in Figure 7A represent the path angle corresponding to the reference signal received by the first device. The two pentagrams are located at the centers of the two beams in the second beam group. Thus, the first device can select these two beams and... As a spatial basis, a first precoding matrix is ​​determined to indicate the two beams and their weights.

[0299] In some implementations, steps A2 and A3 can be combined (or replaced) as follows: the first device determines the first precoding matrix based on the channel under the first beam group. In other words, the channel under the first beam group can be used to determine the first precoding matrix.

[0300] Optionally, the channel under the first beam group can be used to determine the third precoding matrix. The third precoding matrix is ​​the precoding matrix corresponding to the channel under the first beam group determined by the first device, and the third precoding matrix is ​​used to determine the first precoding matrix. Accordingly, the first device can determine the first precoding matrix according to steps B1 to B2.

[0301] Step B1: The first device determines the third precoding matrix based on the channel under the first beam group.

[0302] This application does not restrict the specific implementation of step B1; for example, it can be determined in a manner specified in the agreement.

[0303] For example, for the scenario shown in Figure 4(b), the channel under the first beam group can be the beam domain channel under the first beam group shown in Figure 7A.

[0304] Step B2: The first device can determine the first precoding matrix based on the third precoding matrix.

[0305] For example, as shown in FIG7B, the third precoding matrix is ​​the precoding matrix corresponding to the channel under the first beam group determined by the first device. The first device can determine the first precoding matrix based on the third precoding matrix. The first precoding matrix is ​​the precoding matrix corresponding to the channel under the second beam group.

[0306] Optionally, step B2 may include steps B2-1 to B2-2:

[0307] Step B2-1: The first device can determine the spatial basis of the first precoding matrix (hereinafter referred to as the second spatial basis) based on the spatial basis of the third precoding matrix (hereinafter referred to as the first spatial basis).

[0308] Optionally, the second airspace basis can be W1 is the first spatial basis. F is the conjugate transpose of the weight matrix F0 corresponding to the first beam group. i Let W1 be the weight matrix corresponding to the second beam group. Here, W1 is the identity matrix; or, W1 includes a subset of columns from the identity matrix. This can represent the transformation from beam domain channel to antenna domain channel, F i This can represent the transformation from the antenna domain channel to the beam domain channel, as shown in Figure 7A. This can be understood as transforming the beam domain channel under the first beam group to the antenna domain channel, and then transforming it from the antenna domain channel to the beam domain channel under the second beam group.

[0309] Step B2-2: The first device determines the first precoding matrix based on the second spatial basis.

[0310] For example, the first device may select a beam from a second beam group and determine a first precoding matrix based on the selected beam from the second beam group and a second spatial basis. Again, using Figure 7A as an example, the pentagrams in Figure 7A can represent the path angles corresponding to the reference signals received by the first device. The two pentagrams are not located at the center of the beams in the first beam group, but at the center of the two beams in the second beam group. Thus, the first device may select these two beams and determine a first precoding matrix indicating these two beams and their weights based on these two beams and a second spatial basis.

[0311] Optionally, the channel under the first beam group can be understood as (or can be replaced by) any of the following: the channel corresponding to the first beam group, the beam domain channel under the first beam group, or the beam domain channel corresponding to the first beam group; the channel under the second beam group can be understood as (or can be replaced by) any of the following: the channel corresponding to the second beam group, the beam domain channel under the second beam group, or the beam domain channel corresponding to the second beam group.

[0312] In some possible configurations, the first beam group corresponds to M oversampled beam groups. The first device can select a second beam group from the M oversampled beam groups. Optionally, the second beam group can be one of the M oversampled beam groups such that... The beam group with the highest sparsity. Among them, W is the conjugate transpose of the weight matrix corresponding to the j-th beam group among the M oversampled beam groups, where j takes integer values ​​from 1 to M. (3) This is the third precoding matrix. For example, the M oversampled beamgroups include: the oversampled beamgroup shown in Figure 6A, the oversampled beamgroup shown in Figure 6B, and the oversampled beamgroup shown in Figure 6C. The weight matrix corresponding to the oversampled beamgroup shown in Figure 6A is F1, the weight matrix corresponding to the oversampled beamgroup shown in Figure 6B is F2, and the weight matrix corresponding to the oversampled beamgroup shown in Figure 6C is F3. If The sparsity is higher than and If the sparsity is such that the second beam group can be the oversampled beam group shown in Figure 6C.

[0313] Optionally, if The sparsity of all of them is lower than that of W. (3) If the sparsity is such that the first device can send a fifth message to the second device, the fifth message instructing W... (3) The second device can be based on W (3) Data is sent to the first device. For example, in the scenario shown in Figure 4(a), The sparsity of all of them is lower than that of W. (3) Given the sparsity, the first device can send a fifth message to the second device, the fifth message indicating W. (3) The second device can be based on W (3) Send data to the first device. If the second beam group corresponds to... The sparsity is higher than W (3) If the sparsity is such that the first device can execute S503, then, for example, in the scenario shown in Figure 4(b), The sparsity is higher than W (3) The sparsity of the first device can be executed in S503.

[0314] S503: The first device sends first information; correspondingly, the second device receives the first information.

[0315] The first information indicates the second beam group and / or the first precoding matrix. The second beam group is a set of oversampled beam groups corresponding to the first beam group. The specific content of the second beam group can be found in the description above, and will not be repeated here; the specific content of the first precoding matrix can be found in the description above, and will not be repeated here.

[0316] The method of indicating the second beam group and the first precoding matrix with the first information is described below.

[0317] 1. The first information indicates the second beam group:

[0318] Optionally, the first information may include oversampling parameters corresponding to the second beamgroup. These oversampling parameters can be used to indicate (or configure, or determine) the second beamgroup; for example, they can be used to indicate (or configure, or determine) the weight matrix corresponding to the second beamgroup. Exemplarily, the oversampling parameters may be index information of the weight matrix corresponding to the second beamgroup. For example, the first beamgroup corresponds to M oversampling beamgroups, and the number of these M oversampling beamgroups may be related to O1 and O2, such as M = O1 * O2 - 1. Here, O1 is the oversampling factor in the first direction (e.g., the horizontal direction); O2 is the oversampling factor in the second direction (e.g., the vertical direction). The physical meaning of O1 and O2 is that DFT oversampling increases the number of weight vectors in the first and second directions, thus generating more weight vectors and consequently more oversampling beamgroups. The oversampling parameters corresponding to the second beamgroup may include q1 and q2. q1 can be an integer greater than or equal to 0 and less than or equal to 01-1, and can be used to indicate that the second beam group corresponds to the (q1+1)th weight vector in the first direction; q2 can be an integer greater than or equal to 0 and less than or equal to 02-1, and can be used to indicate that the second beam group corresponds to the (q2+1)th weight vector in the second direction. In this way, the first information can accurately indicate the second beam group through q1 and q2.

[0319] The oversampling parameter may also have other names, such as weight matrix index, second beam group index, etc., without restriction.

[0320] 2. The first information indicates the first precoding matrix:

[0321] The first information may include a PMI (Port Selection Index) used to indicate the first precoding matrix. Optionally, the specific content of the PMI can be found in the explanation of the PS codebook in the terminology section above. For example, the PMI may include at least one of the following: an index for port selection (e.g., i in the terminology explanation section above). 1,1 ), the index corresponding to the delay tap value, or The index corresponding to the amplitude and / or phase values ​​(e.g., i in the terminology explanation section above). 1,4,l i 2,2,l and i 2,1,l , or i 2,4,l and i 2,5,l ).

[0322] Optionally, the second beam group and the first precoding matrix can be used to determine the second precoding matrix; correspondingly, the second device can determine the second precoding matrix based on the second beam group and the first precoding matrix. The second precoding matrix is ​​the precoding matrix corresponding to the channel under the first beam group, and is used by the second device to transmit data. For example, as shown in FIG7C, the first precoding matrix is ​​the precoding matrix corresponding to the channel under the second beam group. The second device can determine the second precoding matrix based on the second beam group and the first precoding matrix. The second precoding matrix is ​​the precoding matrix corresponding to the channel under the first beam group.

[0323] For example, the weight matrix corresponding to the second beam group and the first precoding matrix W (1) and the second precoding matrix W (2) Satisfy the following formula:

[0324] in, F is the conjugate transpose of the weight matrix corresponding to the first beam group. i This is the weight matrix corresponding to the second beam group.

[0325] Optionally, W (1) It can satisfy one of the following formulas:

[0326] or

[0327] Accordingly, W (2) It can satisfy one of the following formulas:

[0328] or

[0329] Among them, W f As the frequency domain basis, W t The time-domain basis is used. W1 is the identity matrix. It is a sparse matrix. The non-zero elements in W1 are feedback parameters; or, W1 includes a subset of columns from the identity matrix. This is the feedback parameter matrix.

[0330] The above formula can be used for the PS codebook. Therefore, this method can increase the degree of freedom of the PS codebook, thereby improving the performance of data transmission based on the PS codebook.

[0331] In this application, the third precoding matrix can be the precoding matrix corresponding to the channel under the first beam group determined by the first device; the second precoding matrix can be the precoding matrix corresponding to the channel under the first beam group determined by the second device. The third precoding matrix and the second precoding matrix can be the same or different. The higher the similarity between the third precoding matrix and the second precoding matrix, the higher the fit between the second precoding matrix and the channel state, and the higher the transmission quality of data transmitted through the second precoding matrix.

[0332] In some possible implementations, in S501, the configuration information may include third information. If the third information indicates that the codebook type of the feedback precoding matrix is ​​a first port selection codebook type, and the codebook of the first port selection codebook type is used to determine the precoding matrix corresponding to the channel under the second beam group, the first device may send the first information; correspondingly, the second device may receive the first information. The specific content of the first port selection codebook type can be found in the description of the first port selection codebook type in S501, and will not be repeated here.

[0333] The initial information can be contained within a traditional message or within a new message. For example, the initial information can be contained within a CSI report.

[0334] Optionally, when the first information is used to indicate the second beam group and the first precoding matrix, the indication information for the second beam group and the indication information for the first precoding matrix can be carried in the same message or in different messages. For example, the indication information for the second beam group can be carried in an RRC message, uplink control information (UCI), or MAC control element (MAC CE), and the indication information for the first precoding matrix can be carried in a CSI report.

[0335] S504: The second device sends the first data; correspondingly, the first device receives the first data.

[0336] Optionally, the second device may send the first data according to the second precoding matrix.

[0337] In some examples, the second precoding matrix If the data to be transmitted is s, and the weight matrix corresponding to the first beam group is F0, then the data transmitted by the second device through the antenna port is... The data received by the first device can be represented as follows:

[0338] In other examples, the second precoding matrix If the data to be transmitted is s, and the weight matrix corresponding to the first beam group is F0, then the data transmitted by the second device through the antenna port is... The data received by the first device can be represented as follows:

[0339] In some other examples, the second precoding matrix If the data to be transmitted is s, and the weight matrix corresponding to the first beam group is F0, then the data transmitted by the second device through the antenna port is... The data received by the first device can be represented as follows:

[0340] S504 is an optional step.

[0341] Using the method shown in Figure 5, when receiving a reference signal through the first beam group, if the path angle corresponding to the reference signal does not perfectly correspond to the beams in the first beam group, the first device can feed back the precoding matrix corresponding to the channel under the second beam group. The second beam group can be an oversampled beam group of the first beam group. Thus, by selecting a suitable second beam group, the correspondence between the path angle corresponding to the reference signal and the beams in the beam group can be improved, thereby reducing the time overhead of feeding back the precoding matrix and reducing the feedback overhead of the precoding matrix.

[0342] Taking the scenario shown in Figure 4(b) as an example, when the method shown in Figure 5 is used, as shown in Figure 7A, the path angle corresponding to the reference signal received by the first device is located at the center of the two beams in the second beam group. In this way, the first device can select these two beams and, based on these two beams, determine and feed back the precoding matrix corresponding to the channel under the second beam group, thereby reducing the feedback overhead of the precoding matrix. Furthermore, in this method, the second device does not need to transmit the reference signal through beams outside the first beam group, thus reducing the time overhead of feeding back the precoding matrix.

[0343] Figure 8 is a flowchart illustrating another communication method provided in an embodiment of this application. As shown in Figure 8, the method may include:

[0344] S801: The second device sends configuration information; correspondingly, the first device receives the configuration information.

[0345] For details on S801, please refer to S501; further details will not be provided here.

[0346] S802: The second device sends at least one reference signal; correspondingly, the first device receives at least one reference signal.

[0347] The at least one reference signal may be carried by the first beam group; the at least one reference signal may be used to determine the channel under the second beam group. For details regarding the at least one reference signal being carried by the first beam group, please refer to the explanation of "the at least one reference signal may be carried by the first beam group" in S502, which will not be repeated here.

[0348] In some implementations, the second device can transmit the at least one reference signal via the weight matrix F0 corresponding to the first beam group, thereby enabling the at least one reference signal to be carried by the first beam group. Assuming any one of the at least one reference signal is x″ and the weight matrix is ​​F0, the signal transmitted by the second device through the antenna port is F0x″. The signal received by the first device can be expressed as: y = HF0x″ + n.

[0349] As previously stated, the at least one reference signal can be used to determine the channel under the second beam group; correspondingly, the first device can determine the channel under the second beam group based on the at least one reference signal.

[0350] In some possible configurations, the at least one reference signal is used to determine the channel under a first beam group, the channel under the first beam group is used to determine the antenna domain channel, and the antenna domain channel is used to determine the channel under a second beam group. Accordingly, the first device can perform steps C1 to C2:

[0351] Step C1: The first device determines the channel under the first beam group based on the at least one reference signal.

[0352] Step C2: The first device determines the antenna domain channel based on the channel under the first beam group, and determines the channel under the second beam group based on the antenna domain channel.

[0353] For details of steps C1 to C2, please refer to steps A1 to A2 in S502, which will not be repeated here.

[0354] Optionally, the channel under the first beam group can be understood as (or can be replaced by) any of the following: the channel corresponding to the first beam group, the beam domain channel under the first beam group, or the beam domain channel corresponding to the first beam group; the channel under the second beam group can be understood as (or can be replaced by) any of the following: the channel corresponding to the second beam group, the beam domain channel under the second beam group, or the beam domain channel corresponding to the second beam group.

[0355] In some possible configurations, the first beam group corresponds to M oversampled beam groups. The first device can select a second beam group from the M oversampled beam groups. For details, please refer to the explanation in S502 regarding "the first device can select a second beam group from the M oversampled beam groups", which will not be repeated here.

[0356] Optionally, if The sparsity of all of them is lower than that of W. (3) Given a certain sparsity, the first device can send sixth information to the second device, indicating the channel under the first beam group; the second device can then send data to the first device based on the channel under the first beam group. W is the conjugate transpose of the weight matrix corresponding to the j-th beam group among the M oversampled beam groups corresponding to the first beam group, where j takes integer values ​​from 1 to M. (3) This is the third precoding matrix, which is the precoding matrix corresponding to the channel under the first beam group determined by the first device. For example, for the scenario shown in Figure 4(a), The sparsity of all of them is lower than that of W. (3) Given the sparsity, the first device can send sixth information to the second device, indicating the channel under the first beam group; the second device can then send data to the first device based on the channel under the first beam group. If the second beam group corresponds to... The sparsity is higher than W (3) If the sparsity is such that the first device can execute S803, then, for example, in the scenario shown in Figure 4(b), The sparsity is higher than W (3) The sparsity of the first device can be executed in S803.

[0357] S803: The first device sends the seventh information; correspondingly, the second device receives the seventh information.

[0358] The seventh information is used to indicate the second beam group and / or the channel under the second beam group. The second beam group is a set of oversampled beam groups corresponding to the first beam group. The specific content of the seventh information indicating the second beam group can be found in the description of "the first information indicating the second beam group" in S503, except that the first information is replaced by the seventh information, and will not be repeated here. This application does not limit the specific method by which the seventh information indicates the channel under the second beam group.

[0359] Optionally, the second beam group and the channels under the second beam group can be used to determine the second precoding matrix; correspondingly, the second device can determine the second precoding matrix based on the second beam group and the channels under the second beam group. The second precoding matrix is ​​the precoding matrix corresponding to the channels under the first beam group, and the second precoding matrix is ​​used by the second device to transmit data.

[0360] For example, the channels under the second beam group can be used to determine the first precoding matrix, which is the precoding matrix corresponding to the channels under the second beam group. The second beam group and the first precoding matrix can be used to determine the second precoding matrix. Correspondingly, the second device can determine the first precoding matrix based on the channels under the second beam group, and determine the second precoding matrix based on the second beam group and the first precoding matrix. The specific content of the second device determining the second precoding matrix based on the second beam group and the first precoding matrix can be found in the explanation of "the second device can determine the second precoding matrix based on the second beam group and the first precoding matrix" in S503, and will not be repeated here.

[0361] In some possible implementations, in S801, the configuration information may include third information. If the third information indicates that the codebook type of the feedback precoding matrix is ​​a first port selection codebook type, and the codebook of the first port selection codebook type is used to determine the precoding matrix corresponding to the channel under the second beam group, the first device may send seventh information; correspondingly, the second device may receive the seventh information. The specific content of the first port selection codebook type can be found in the description of the first port selection codebook type in S501, and will not be repeated here.

[0362] Optionally, when the seventh information is used to indicate the second beam group and the channel under the second beam group, the indication information of the second beam group and the indication information of the channel under the second beam group can be carried in the same message or in different messages. For example, the indication information of the second beam group can be carried in an RRC message, UCI, or MAC CE, and the indication information of the channel under the second beam group can be carried in a CSI report.

[0363] S804: The second device sends the first data; correspondingly, the first device receives the first data.

[0364] For details on S804, please refer to S504; further details will not be provided here.

[0365] Using the method shown in Figure 8, when receiving a reference signal through the first beam group, if the path angle corresponding to the reference signal does not perfectly correspond to the beams in the first beam group, the first device can feed back the channel under the second beam group. The second beam group can be an oversampled beam group of the first beam group. Thus, by selecting a suitable second beam group, the correspondence between the path angle corresponding to the reference signal and the beams in the beam group can be improved, thereby reducing the time overhead of the feedback channel and the feedback cost of the channel.

[0366] Taking the scenario shown in Figure 4(b) as an example, when the method shown in Figure 8 is used, as shown in Figure 7A, the path angle corresponding to the reference signal received by the first device is located at the center of the two beams in the second beam group. In this way, the first device can select these two beams and determine and feed back the channel under the second beam group based on these two beams, thereby reducing the channel feedback overhead. Furthermore, in this method, the second device does not need to transmit the reference signal through beams outside the first beam group, thereby reducing the time overhead of channel feedback.

[0367] Based on the same technical concept as the above-described method embodiments, this application provides a corresponding communication device that can be used to perform the functions of the relevant steps in the above-described method embodiments. This function can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. The communication device can be a terminal or access network device, or a device within the terminal or access network device (e.g., a module, communication module, circuit or chip responsible for communication functions (such as a modem chip, or a SoC chip or SIP chip containing a modem core), chip system, or processor), or a logical node, logical module, or software capable of implementing all or part of the functions of the terminal or access network device.

[0368] In one possible implementation, the communication device provided in this application embodiment has the structure shown in FIG9, including a processing unit 902. Optionally, the communication device further includes an interface unit 901. The functions of each unit in the communication device 900 are described below.

[0369] Interface unit 901 is used for inputting and / or outputting information. Input information can be replaced by received information, and output information can be replaced by transmitted information. When outputting information, interface unit 901 can output information to other devices outside of communication device 900, or to other units within communication device 900. In some embodiments, interface unit 901 can be implemented through at least one of a physical interface, a communication module, a communication interface, and an input / output interface. In other embodiments, interface unit 901 can be implemented through an interface circuit, such as a mobile communication module. The mobile communication module may include one or more of at least one antenna, at least one filter, a switch, a power amplifier, a low noise amplifier (LNA), etc. Interface unit 901 is used to perform the receiving and transmitting operations in the above method embodiments.

[0370] In this application, the interface unit 901 may also have other names, such as a transceiver unit or a communication unit. Optionally, the interface unit 901 may include a receiving unit and / or a sending unit, used for inputting information and outputting information, respectively. The receiving unit is used to perform the receiving operation in the above method embodiments. The sending unit is used to perform the sending operation in the above method embodiments.

[0371] The processing unit 902 can be used to support the communication device 900 in performing the processing actions in the above method embodiments. The processing unit 902 can be implemented by one or more processors. For example, the processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), microprocessors (MCUs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor. The processing unit 902 is used to perform processing-related operations in the above method embodiments, for example, to instruct operations other than receiving and transmitting operations in the above method embodiments.

[0372] In one embodiment, the communication device 900 is applied to the first device in the embodiment of this application shown in FIG5. The specific functions of the processing unit 902 in this embodiment will be described below.

[0373] The processing unit 902 is configured to: receive at least one reference signal through the interface unit 901, wherein the at least one reference signal is carried by a first beam group, and the at least one reference signal is used to determine a first precoding matrix, wherein the first precoding matrix is ​​a precoding matrix corresponding to a channel under a second beam group, and the second beam group is a set of oversampled beam groups corresponding to the first beam group; and send first information through the interface unit 901, wherein the first information is used to indicate: the second beam group and / or the first precoding matrix.

[0374] In some possible ways, the processing unit 902 is also used to: receive second information through the interface unit 901, the second information being used to indicate the first beam group.

[0375] Optionally, the processing unit 902 is further configured to: receive third information through the interface unit 901, the third information being used to indicate the codebook type of the feedback precoding matrix; and send first information through the interface unit 901 when the third information indicates that the codebook type of the feedback precoding matrix is ​​the first port selection codebook type, and the codebook of the first port selection codebook type is used to determine the precoding matrix corresponding to the channel under the second beam group.

[0376] In some possible ways, the processing unit 902 is also configured to: receive fourth information through the interface unit 901, the fourth information being used to indicate the number of oversampled beam groups corresponding to the first beam group.

[0377] In another embodiment, the communication device 900 is applied to the second device in the embodiment of this application shown in FIG5. The specific functions of the processing unit 902 in this embodiment will be described below.

[0378] The processing unit 902 is configured to: transmit at least one reference signal through the interface unit 901, wherein the at least one reference signal is carried by a first beam group, and the at least one reference signal is used to determine a first precoding matrix, wherein the first precoding matrix is ​​a precoding matrix corresponding to a channel under a second beam group, and the second beam group is a set of oversampled beam groups corresponding to the first beam group; and receive first information through the interface unit 901, wherein the first information is used to indicate: the second beam group and / or the first precoding matrix.

[0379] In some possible ways, the processing unit 902 is also used to: send second information through the interface unit 901, the second information being used to indicate the first beam group.

[0380] Optionally, the processing unit 902 is further configured to: send third information through the interface unit 901, the third information being used to indicate the codebook type of the feedback precoding matrix; and receive the first information through the interface unit 901 when the third information indicates that the codebook type of the feedback precoding matrix is ​​the first port selection codebook type, and the codebook of the first port selection codebook type is used to determine the precoding matrix corresponding to the channel under the second beam group.

[0381] In some possible ways, the processing unit 902 is also used to: send fourth information through the interface unit 901, the fourth information being used to indicate the number of oversampled beam groups corresponding to the first beam group.

[0382] In another embodiment, the communication device 900 is applied to the first device in the embodiment of this application shown in FIG8. The specific functions of the processing unit 902 in this embodiment will be described below.

[0383] The processing unit 902 is configured to: receive at least one reference signal through the interface unit 901, wherein the at least one reference signal is carried by a first beam group and the at least one reference signal is used to determine the channel under a second beam group, wherein the second beam group is a set of oversampled beam groups corresponding to the first beam group; and send seventh information through the interface unit 901, wherein the seventh information is used to indicate the second beam group and / or the channel under the second beam group.

[0384] In some possible ways, the processing unit 902 is also used to: receive second information through the interface unit 901, the second information being used to indicate the first beam group.

[0385] Optionally, the processing unit 902 is further configured to: receive third information through the interface unit 901, the third information being used to indicate the codebook type of the feedback precoding matrix; and send seventh information through the interface unit 901 when the third information indicates that the codebook type of the feedback precoding matrix is ​​the first port selection codebook type, and the codebook of the first port selection codebook type is used to determine the precoding matrix corresponding to the channel under the second beam group.

[0386] In some possible ways, the processing unit 902 is also configured to: receive fourth information through the interface unit 901, the fourth information being used to indicate the number of oversampled beam groups corresponding to the first beam group.

[0387] In another embodiment, the communication device 900 is applied to the second device in the embodiment of this application shown in FIG8. The specific functions of the processing unit 902 in this embodiment will be described below.

[0388] The processing unit 902 is configured to: transmit at least one reference signal through the interface unit 901, wherein the at least one reference signal is carried by a first beam group and the at least one reference signal is used to determine the channel under a second beam group, wherein the second beam group is a set of oversampled beam groups corresponding to the first beam group; and receive seventh information through the interface unit 901, wherein the seventh information is used to indicate the second beam group and / or the channel under the second beam group.

[0389] In some possible ways, the processing unit 902 is also used to: send second information through the interface unit 901, the second information being used to indicate the first beam group.

[0390] Optionally, the processing unit 902 is further configured to: send third information through the interface unit 901, the third information being used to indicate the codebook type of the feedback precoding matrix; and receive seventh information through the interface unit 901 when the third information indicates that the codebook type of the feedback precoding matrix is ​​the first port selection codebook type, and the codebook of the first port selection codebook type is used to determine the precoding matrix corresponding to the channel under the second beam group.

[0391] In some possible ways, the processing unit 902 is also used to: send fourth information through the interface unit 901, the fourth information being used to indicate the number of oversampled beam groups corresponding to the first beam group.

[0392] In one possible design, when the communication device 900 is a communication equipment or a communication module within a communication equipment, the functionality of the processing unit 902 can be implemented by one or more processors. For example, the processor may include a modem chip, or a system-on-a-chip (SoC) or SIP chip containing a modem core. The functionality of the interface unit 901 can be implemented by transceiver circuitry.

[0393] In one possible design, when the communication device 900 is a circuit or chip responsible for communication functions in a communication device, such as a modem chip or a system-on-a-chip (SoC) or SIP chip containing a modem core, the function of the processing unit 902 can be implemented by a circuit system in the aforementioned chip that includes one or more processors or processor cores. The function of the interface unit 901 can be implemented by the interface circuit or data transceiver circuit on the aforementioned chip.

[0394] The communication device can be a terminal or an access network device.

[0395] A more detailed description of the processing unit 902 and the interface unit 901 can be obtained directly from the relevant descriptions in the method embodiments shown in Figures 5 to 8, and will not be repeated here.

[0396] It should be noted that the module division in the above embodiments of this application is illustrative and only represents a logical functional division. In actual implementation, there may be other division methods. Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, exist as separate physical units, or have two or more units integrated into one unit. The integrated units can be implemented in hardware, as software functional units, or in a combination of hardware and software. Whether a function is executed 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.

[0397] For example, the functional unit in any of the above devices may be one or more integrated circuits configured to implement the above methods, such as one or more ASICs, one or more CPUs, one or more MCUs, one or more DSPs, or one or more FPGAs, or a combination of at least two of these integrated circuit forms.

[0398] If the integrated units described above 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 all or part 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.) or processor 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 (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0399] In one possible implementation, the communication device provided in this application embodiment is shown in FIG10. The communication device 1000 includes a processor 1002. Optionally, the communication device 1000 further includes an interface circuit 1001 and a memory 1003. The interface circuit 1001, the processor 1002, and the memory 1003 are coupled to each other.

[0400] Optionally, the interface circuit 1001, processor 1002, and memory 1003 are coupled to each other via bus 1004. Bus 1004 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. Buses can be divided into address buses, data buses, control buses, etc. For ease of illustration, only one thick line is used in Figure 10, but this does not mean that there is only one bus or one type of bus.

[0401] Interface circuit 1001 is used for inputting and / or outputting information. Input information can be replaced with received information, and output information can be replaced with transmitted information. When outputting information, interface circuit 1001 can output information to other devices outside of communication device 1000, or to other units within communication device 1000. For example, interface circuit 1001 can be implemented through at least one of a physical interface, a communication module, a communication interface, an input / output interface, and a mobile communication module. The mobile communication module may include one or more of at least one antenna, at least one filter, a switch, a power amplifier, an LNA, etc. Interface circuit 1001 is used to perform the receiving and transmitting operations in the above method embodiments.

[0402] The interface circuit 1001 may be one of the following: a transceiver, a transceiver circuit, a communication circuit, an interface, a communication interface, or an input / output interface (e.g., a chip's input / output interface). The interface circuit 1001 may include an input interface circuit and an output interface circuit, used for inputting information and outputting information, respectively. The input interface circuit is used to perform the receiving operation in the above method embodiments. The output interface circuit is used to perform the transmitting operation in the above method embodiments.

[0403] The transceiver can be used for communication with other communication devices. For example, if communication device 1000 is a terminal, the transceiver can be used to communicate with access network equipment or with another terminal. As another example, if communication device 1000 is an access network device, the transceiver can be used to communicate with a terminal or with another access network device.

[0404] Optionally, the transceiver may include a receiver and / or a transmitter. The receiver is used to perform the receiving operation in the above method embodiments. The transmitter is used to perform the sending operation in the above method embodiments.

[0405] Optionally, the transceiver can be integrated with the processor 1002 or exist independently and be coupled to the processor 1002 through the interface circuit of the communication device 1000. This application embodiment does not specifically limit this.

[0406] Processor 1002 can be used to support communication device 1000 in performing the processing actions in the above method embodiments. When communication device 1000 is used to implement the above method embodiments, processor 1002 can also be used to implement the functions of processing unit 902. Processor 1002 can be a CPU, or other general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. General-purpose processors can be microprocessors or any conventional processor. Processor 1002 is used to perform processing-related operations in the above method embodiments, for example, to instruct operations other than receiving and sending operations in the above method embodiments.

[0407] In one embodiment, the communication device 1000 is applied to the first device in the embodiment of this application shown in FIG5. The specific functions of the processor 1002 in this embodiment will be described below.

[0408] The processor 1002 is configured to: receive at least one reference signal via interface circuit 1001, wherein the at least one reference signal is carried by a first beam group, and the at least one reference signal is used to determine a first precoding matrix, wherein the first precoding matrix is ​​a precoding matrix corresponding to a channel under a second beam group, and the second beam group is a set of oversampled beam groups corresponding to the first beam group; and transmit first information via interface circuit 1001, wherein the first information is used to indicate the second beam group and the first precoding matrix.

[0409] In another embodiment, the communication device 1000 is applied to the second device in the embodiment of this application shown in FIG5. The specific functions of the processor 1002 in this embodiment will be described below.

[0410] The processor 1002 is configured to: transmit at least one reference signal via interface circuit 1001, wherein the at least one reference signal is carried by a first beam group, and the at least one reference signal is used to determine a first precoding matrix, wherein the first precoding matrix is ​​a precoding matrix corresponding to a channel under a second beam group, and the second beam group is a set of oversampled beam groups corresponding to the first beam group; and receive first information via interface circuit 1001, wherein the first information is used to indicate the second beam group and the first precoding matrix.

[0411] In another embodiment, the communication device 1000 is applied to the first device in the embodiment of this application shown in FIG8. The specific functions of the processor 1002 in this embodiment will be described below.

[0412] The processor 1002 is configured to: receive at least one reference signal via interface circuit 1001, wherein the at least one reference signal is carried by a first beam group and the at least one reference signal is used to determine the channel under a second beam group, wherein the second beam group is a set of oversampled beam groups corresponding to the first beam group; and send seventh information via interface circuit 1001, wherein the seventh information is used to indicate the second beam group and the channel under the second beam group.

[0413] In another embodiment, the communication device 1000 is applied to the second device in the embodiment of this application shown in FIG8. The specific functions of the processor 1002 in this embodiment will be described below.

[0414] The processor 1002 is configured to: transmit at least one reference signal via interface circuit 1001, wherein the at least one reference signal is carried by a first beam group and the at least one reference signal is used to determine the channel under a second beam group, wherein the second beam group is a set of oversampled beam groups corresponding to the first beam group; and receive seventh information via interface circuit 1001, wherein the seventh information is used to indicate the second beam group and the channel under the second beam group.

[0415] The specific functions of processor 1002 can be found in the description of the communication methods provided in the above embodiments and examples of this application, as well as the specific functional description of communication device 900 in the embodiment of this application shown in FIG9, which will not be repeated here.

[0416] Memory 1003 is used to store program instructions and / or data. Specifically, program instructions may include program code, which includes computer operation instructions. Memory 1003 may include RAM and may also include non-volatile memory, such as at least one disk storage device. Processor 1002 executes the program instructions stored in memory 1003 and uses the data stored in memory 1003 to implement the above-mentioned functions, thereby realizing the communication method provided in the embodiments of this application. Memory 1003 may be integrated with processor 1002 or may be a memory outside the communication device.

[0417] It is understood that the memory 1003 in Figure 10 of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be ROM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be RAM, which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0418] This application also provides a communication device 1100, which can be a terminal, a processor in the terminal, or a chip. The communication device 1100 can be used to perform the operations performed by the first device in the above method embodiments.

[0419] When the communication device 1100 is a terminal, Figure 11 shows a schematic diagram of the terminal structure. As shown in Figure 11, the terminal includes a processor, a memory, and a transceiver. The memory can store computer program code, and the transceiver includes a transmitter 1131, a receiver 1132, radio frequency circuitry (not shown in the figure), an antenna 1133, and input / output devices (not shown in the figure).

[0420] The processor is mainly used to process communication protocols and communication data; control terminals; execute software programs; and process data from software programs.

[0421] Memory is mainly used to store software programs and data.

[0422] Radio frequency (RF) circuits are mainly used for the conversion between baseband signals and RF signals, as well as for the processing of RF signals.

[0423] Antennas are primarily used for transmitting and receiving radio frequency signals in the form of electromagnetic waves.

[0424] Input / output devices can include touchscreens, displays, or keyboards. They are primarily used to receive user input and output data to the user. It should be noted that some types of terminals may not have input / output devices.

[0425] When data needs to be transmitted, the processor performs baseband processing on the data to be transmitted and outputs a baseband signal to the radio frequency (RF) circuit. The RF circuit then processes the baseband signal and transmits it outwards as electromagnetic waves via an antenna. When data is sent to the terminal, the RF circuit receives the RF signal through the antenna. The RF circuit converts the RF signal back into a baseband signal and outputs it to the processor. The processor converts the baseband signal back into data and processes that data.

[0426] For ease of explanation, Figure 11 shows only one memory, processor, and transceiver. In actual terminal products, there may be one or more processors and one or more memories. Memory may also be called storage medium or storage device, etc. Memory may be set up independently of the processor or integrated with the processor; this application embodiment does not impose any limitations on this.

[0427] In the embodiments of this application, the antenna and radio frequency circuit with transceiver function can be regarded as the interface unit of the terminal, and the processor with processing function can be regarded as the processing unit of the terminal.

[0428] As shown in Figure 11, the terminal includes a processor 1110, a memory 1120, and a transceiver 1130. The processor 1110 may also be referred to as a processing board, processing module, or processing device. The transceiver 1130 may also be referred to as an interface circuit, transceiver, or transceiver device. The processor 1110 is used to execute the processing operations on the first device side in the above method embodiments. The transceiver 1130 is used to execute the transmit and receive operations on the first device side in the above method embodiments.

[0429] Optionally, the device in transceiver 1130 used for receiving functions can be considered a receiver, and the device in transceiver 1130 used for transmitting functions can be considered a transmitter; that is, transceiver 1130 includes a receiver 1132 and a transmitter 1131. A receiver may also be called a receiver module or receiving circuit, etc. A transmitter may also be called a transmitter, transmitter module, or transmitting circuit, etc. The receiver is used to perform the receiving operation on the first device side in the above method embodiments. The transmitter is used to perform the transmitting operation on the first device side in the above method embodiments.

[0430] It should be understood that Figure 11 is merely an example and not a limitation, and the terminal may not depend on the structure shown in Figure 11.

[0431] When the communication device 1100 is a chip, the chip includes a processor and a transceiver. The transceiver can be an input / output circuit or a communication interface. The processor can be a processing module integrated on the chip, a microprocessor, or an integrated circuit. In the above method embodiments, the transmitting operation of the first device can be understood as the output of the chip, and the receiving operation of the first device in the above method embodiments can be understood as the input of the chip.

[0432] The communication device 1100 may also include a memory, which may be a memory built into the chip or an external memory.

[0433] This application also provides a communication device 1200, which can be an access network device or a chip. The communication device 1200 can be used to perform the operations performed by the second device in the above method embodiments.

[0434] When the communication device 1200 is an access network device, such as a base station, Figure 12 shows a schematic diagram of the structure of an access network device. The access network device includes parts 1210, 1220, and 1230.

[0435] The 1210 section is mainly used for baseband processing and controlling access network equipment; the 1210 section is usually the control center of the base station, which can be called a processor, and is used to control the access network equipment to perform the processing operations on the second device side in the above method embodiment.

[0436] Section 1220 is primarily used to store computer program code and data.

[0437] Section 1230 is primarily used for transmitting and receiving radio frequency (RF) signals, as well as converting RF signals to baseband signals. Section 1230 is commonly referred to as a transceiver module, transceiver, transceiver circuit, interface circuit, or transceiver unit. Section 1230 may include antenna 1233 and RF circuitry (not shown in the figure), where the RF circuitry is mainly used for RF processing. Section 1230 can be used to perform the transmit and receive operations on the second device side in the above method embodiments.

[0438] Optionally, the device used to implement the receiving function in part 1230 can be regarded as a receiver, and the device used to implement the transmitting function can be regarded as a transmitter. That is, part 1230 includes receiver 1232 and transmitter 1231. The receiver can also be called a receiving module, receiver circuit, etc., and the transmitter can be called a transmitter, transmitting module, transmitter, or transmitting circuit, etc. The receiver is used to perform the receiving operation on the second device side in the above method embodiments. The transmitter is used to perform the transmitting operation on the second device side in the above method embodiments.

[0439] Sections 1210 and 1220 may include one or more single boards, each single board may include one or more processors and one or more memories. The processor is used to read and execute programs in the memory to implement baseband processing functions and control access network devices. If multiple single boards exist, they can be interconnected to enhance processing capabilities. As an optional implementation, multiple single boards may share one or more processors, multiple single boards may share one or more memories, or multiple single boards may simultaneously share one or more processors.

[0440] It should be understood that Figure 12 is merely an example and not a limitation, and access network devices may not depend on the structure shown in Figure 12.

[0441] When the communication device 1200 is a chip, the chip includes a transceiver and a processor. The transceiver can be an input / output circuit or a communication interface; the processor can be a processor integrated on the chip, a microprocessor, or an integrated circuit. In the above method embodiments, the transmitting operation of the second device can be understood as the chip's output, and the receiving operation of the second device in the above method embodiments can be understood as the chip's input.

[0442] The communication device 1200 may also include a memory, which may be a memory built into the chip or an external memory.

[0443] Based on the above embodiments, this application also provides a computer program product including computer-executable instructions, which, when run, causes the methods provided in the above embodiments to be executed.

[0444] Based on the above embodiments, this application also provides a computer-readable storage medium storing a computer program or instructions, which, when executed by a computer, causes the computer to perform the methods provided in the above embodiments.

[0445] The storage medium can be any available medium that a computer can access. For example, but not limited to, a computer-readable medium can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0446] Based on the above embodiments, this application also provides a chip for reading a computer program stored in a memory and implementing the method provided in the above embodiments.

[0447] Based on the above embodiments, this application provides a chip system including a processor for supporting a computer device in implementing the functions involved in the devices in the above embodiments. In one possible design, the chip system further includes a memory for storing necessary programs and data of the computer device. The chip system may be composed of chips or may include chips and other discrete components.

[0448] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0449] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or one or more blocks of the block diagrams.

[0450] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0451] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0452] In this application, the terms "system" and "network" are used interchangeably. "At least one item" refers to one or more items, and "more than one item" refers to two or more items. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. In the textual description of this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0453] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

[0454] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A communication method characterized by comprising: Applied to the first device, comprising: At least one reference signal is received, the at least one reference signal is carried by a first beam group, the at least one reference signal is used to determine a first precoding matrix, the first precoding matrix is ​​the precoding matrix corresponding to the channel under a second beam group, and the second beam group is a set of oversampled beam groups corresponding to the first beam group; Send a first message, which indicates the second beam group and the first precoding matrix.

2. The method of claim 1, wherein, Also includes: Receive second information, which is used to indicate the first beam group.

3. The method of claim 1 or 2, wherein, Also includes: Receive third information, which is used to indicate the codebook type of the feedback precoding matrix; Sending the first information includes: when the third information indicates that the codebook type of the feedback precoding matrix is ​​a first port selection codebook type, and the codebook of the first port selection codebook type is used to determine the precoding matrix corresponding to the channel under the second beam group, sending the first information.

4. The method according to any one of claims 1 to 3, characterized in that, Also includes: Receive fourth information, which indicates the number of oversampled beam groups corresponding to the first beam group.

5. A communication method characterized by comprising: Applied to a second device, comprising: At least one reference signal is transmitted, the at least one reference signal being carried by a first beam group, the at least one reference signal being used to determine a first precoding matrix, the first precoding matrix being a precoding matrix corresponding to a channel under a second beam group, the second beam group being a set of oversampled beam groups corresponding to the first beam group; Receive first information, which indicates the second beam group and the first precoding matrix.

6. The method of claim 5, wherein, Also includes: Send a second message, which is used to instruct the first beam group.

7. The method of claim 5 or 6, wherein, Also includes: Send a third message, which is used to indicate the codebook type of the feedback precoding matrix; Receiving the first information includes: receiving the first information when the third information indicates that the codebook type of the feedback precoding matrix is ​​a first port selection codebook type, and the codebook of the first port selection codebook type is used to determine the precoding matrix corresponding to the channel under the second beam group.

8. The method according to any one of claims 5 to 7, characterized in that, Also includes: Send a fourth message, which indicates the number of oversampled beam groups corresponding to the first beam group.

9. The method of claim 2 or 6, wherein, The first beam group includes at least one beam, and the second information is used to indicate the first beam group, including at least one of the following: The second information includes the index of each of the at least one beam; The second information includes a first bitmap, which is used to indicate the at least one beam; or, The second information includes the index of the first beam group.

10. The method according to any one of claims 1 to 9, characterized in that, The at least one reference signal is used to determine the first precoding matrix, including: The at least one reference signal is used to determine the channel under the first beam group, the channel under the first beam group is used to determine the antenna domain channel, the antenna domain channel is used to determine the channel under the second beam group, and the channel under the second beam group is used to determine the first precoding matrix.

11. The method according to any one of claims 1 to 10, wherein, The second beam group and the first precoding matrix are used to determine the second precoding matrix, which is used by the second device to transmit data. The second precoding matrix is ​​the precoding matrix corresponding to the channel under the first beam group.

12. The method of claim 11, wherein, The weight matrix corresponding to the second beam group, the first precoding matrix, and the second precoding matrix satisfy the following formula: wherein W (2) is the second precoding matrix, is a weight matrix corresponding to the first beam group, W i is a weight matrix corresponding to the second beam group, W (1) is the first precoding matrix.

13. The method of claim 12, wherein, The first precoding matrix satisfies one of the following equations: or where W f is a frequency domain basis, W t is a time domain basis; W1 is an identity matrix, for sparse matrices, nonzero elements in W1 are feedback parameters; or, W1 includes some columns of the identity matrix, This is the feedback parameter matrix.

14. The method of any one of claims 1 to 13, wherein, The first information is used to indicate the second beam group, including: The first information includes oversampling parameters corresponding to the second beam group, the oversampling parameters being used to indicate the second beam group.

15. The method of any one of claims 1 to 14, wherein, The at least one reference signal includes at least one Channel State Information Reference Signal (CSI-RS).

16. A communications device, characterized by Includes a unit for performing the method as described in any one of claims 1-15.

17. A communications device, characterized by Includes a processor for executing computer programs or instructions that cause the apparatus to perform the method as described in any one of claims 1-15.

18. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program or instructions, which, when executed, implement the method as described in any one of claims 1-15.

19. A computer program product, characterised in that, The computer program product includes: computer program code, which, when the computer program code is run, implements the method as described in any one of claims 1-15.

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