CN111970036A

CN111970036A - Communication method and communication device

Info

Publication number: CN111970036A
Application number: CN201910419636.2A
Authority: CN
Inventors: 刘建琴; 陈铮
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-05-20
Filing date: 2019-05-20
Publication date: 2020-11-20
Also published as: WO2020233500A1

Abstract

The application provides a communication method and a device, and the method comprises the following steps: after the number of receiving antennas used by a terminal device for receiving a PDSCH sent by a network device changes, the terminal device determines a first CSI according to the changed number of the receiving antennas, wherein the first CSI is a CSI reported to the network device by the terminal device according to a result of measuring a CSI-RS by the changed number of the receiving antennas; and the terminal equipment receives the PDSCH sent by the network equipment according to the first CSI. According to the method and the device, after the number of the receiving antennas used by the terminal equipment is changed, the network equipment can perform downlink data scheduling with the terminal equipment by using the accurate CSI, so that the use experience of a user is improved.

Description

Communication method and communication device

Technical Field

The present application relates to the field of communications, and more particularly, to a communication method and a communication apparatus.

Background

A channel-state information reference signal (CSI-RS) is a type of reference signal used for measuring a downlink channel. The terminal device may perform downlink channel measurement based on the CSI-RS sent by the network device to obtain Channel State Information (CSI) of the downlink channel, and report the CSI to the network device, and the network device schedules the downlink resource according to the CSI.

When the number of receiving antennas (receivers, Rx) of the terminal device is different, the energy consumption of the terminal device is different, for example, the energy consumption when the receiving antenna of the terminal device is 1Rx is 70% of that when the receiving antenna of the terminal device is 2 Rx. In future communication systems, the receiving antenna of the terminal device may be dynamically changed due to factors such as saving energy consumption. The current CSI measurement and reporting mechanism is not reasonable enough, and the accuracy of scheduling or data transmission by the network device may be affected within a period of time after the number of receiving antennas is switched.

Disclosure of Invention

The application provides a communication method and a communication device, after the number of receiving antennas used by a terminal device changes, a network device can perform downlink data scheduling with the terminal device by using more accurate CSI, so that the use experience of a user is improved.

In a first aspect, a communication method is provided, which may be executed by a terminal device, or may also be executed by a chip or a circuit configured in the terminal device, and this application is not limited thereto.

Specifically, the method comprises the following steps: after the number of receiving antennas used by the terminal equipment for receiving the PDSCH sent by the network equipment is changed, the terminal equipment determines first CSI according to the changed number of the receiving antennas, wherein the first CSI is CSI reported to the network equipment by the terminal equipment according to the result of measuring the CSI-RS by using the changed number of the receiving antennas; and the terminal equipment receives the PDSCH sent by the network equipment according to the first CSI.

In this embodiment of the application, after the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device changes, the terminal device may determine the first CSI according to the changed number of receiving antennas, where the first CSI and the changed number of receiving antennas have a corresponding relationship. Specifically, the first CSI is CSI reported by the terminal device to the network device, and the terminal device receives the CSI-RS with the changed number of receiving antennas, measures the CSI-RS, generates and reports the CSI to the network device according to a measurement result.

The network device may perform downlink data transmission with the terminal device according to the first CSI, and the terminal device may also perform data reception according to a reception algorithm corresponding to the first CSI. Because the first CSI used by the network equipment and the terminal equipment has a corresponding relation with the current receiving antenna quantity, and the first CSI is matched with the current real channel quality, after the receiving antenna quantity of the terminal equipment changes, the network equipment can perform downlink data scheduling with the terminal equipment by using the more accurate CSI, so that the use experience of a user is improved.

With reference to the first aspect, in some implementations of the first aspect, the determining, by the terminal device, the first CSI according to the changed number of receiving antennas includes: the terminal equipment determines first CSI according to the changed number of the receiving antennas under the condition that the terminal equipment does not report the CSI to the network equipment according to the result of measuring the CSI-RS by the changed number of the receiving antennas and receives the PDCCH sent by the network equipment; the method for receiving the PDSCH sent by the network equipment by the terminal equipment according to the first CSI comprises the following steps: and the terminal equipment receives the PDSCH scheduled by the PDCCH according to the first CSI.

With reference to the first aspect, in certain implementations of the first aspect, the changed number of receiving antennas is a first number of receiving antennas, where the method further includes: the terminal equipment determines the number of first receiving antennas according to the configuration of the first CSI resources; the terminal equipment measures a first CSI-RS in a first CSI resource configuration sent by the network equipment according to the number of first receiving antennas; and the terminal equipment reports the first CSI to the network equipment according to the result of measuring the first CSI-RS.

Specifically, in the embodiment of the present application, the first CSI resource configuration is associated with (or corresponds to) the first number of receiving antennas, and the terminal device can only receive and measure the first CSI-RS in the first CSI resource configuration by the first number of receiving antennas, and cannot receive and measure the first CSI-RS in the first CSI resource configuration by using other numbers of receiving antennas. If the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device is not the first number of receiving antennas when performing measurement (receiving the first CSI-RS in the first CSI resource configuration), the terminal device should switch the number of receiving antennas to the first number of receiving antennas in advance, and then receive and measure the first CSI-RS. The higher layer signaling may configure its associated number of terminal device receive antennas when configuring the first CSI resource configuration.

It is readily understood that the terminal device may support the number of using multiple receive antennas, and may choose to receive PDSCH transmitted by the network device using one or more of the multiple receive antennas in different situations. The first number of receiving antennas may be any one of the numbers of receiving antennas that can be used by the terminal device.

Optionally, the first number of receiving antennas may be the maximum number of receiving antennas that can be used by the terminal device.

Optionally, the first number of receiving antennas may be any number of receiving antennas except for the non-minimum number of receiving antennas that can be used by the terminal device.

Optionally, the first number of receiving antennas may be a minimum number of receiving antennas that can be used by the terminal device.

Optionally, the first CSI resource configuration may include parameters related to time domain behavior of the transmitting first CSI-RS.

Optionally, the first CSI-RS may be periodically transmitted, or the first CSI-RS may be semi-persistently scheduled, or the first CSI-RS may be non-periodically transmitted.

Optionally, the first CSI may be reported to the network device according to the first CSI reporting configuration.

Optionally, the first CSI reporting configuration may be associated with the first CSI resource configuration. The first CSI reporting configuration may include a time-domain behavior of CSI feedback, a measurement constraint configuration, CSI feedback parameters, and the like. Wherein the time-domain behavior of the CSI feedback includes configuring the CSI feedback as periodic, semi-continuous, or aperiodic CSI feedback.

With reference to the first aspect, in certain implementations of the first aspect, the changed number of receiving antennas is a second number of receiving antennas, where the method further includes: the terminal equipment measures a second CSI-RS in a second CSI resource configuration sent by the network equipment according to the number of second receiving antennas, wherein the number of the second receiving antennas is the number of the receiving antennas used for receiving the PDSCH sent by the network equipment when the terminal equipment carries out measurement; and the terminal equipment reports the first CSI to the network equipment according to the result of measuring the second CSI-RS.

Specifically, the second CSI resource configuration is associated with the number of receiving antennas (or the number of currently used receiving antennas) used by the terminal device to receive the PDSCH transmitted by the network device when the measurement is performed. And the terminal equipment receives and measures the second CSI-RS in the second CSI resource configuration by using the number of receiving antennas for receiving the PDSCH sent by the network equipment during measurement.

For example, when performing the measurement, the terminal device receives the PDSCH transmitted by the network device with the second number of receiving antennas, and at this time, the terminal device may continue to receive and measure the second CSI-RS in the second CSI resource configuration with the second number of receiving antennas. The second number of receiving antennas may be any one of the numbers of receiving antennas that can be used by the terminal device, such as a maximum number of receiving antennas or a minimum number of receiving antennas.

Alternatively, the number of the second receiving antennas may be the same as the number of the first receiving antennas.

Optionally, the second CSI resource configuration may include parameters related to the time domain behavior of the second CSI-RS.

Optionally, the second CSI-RS may be periodically transmitted, or the second CSI-RS may be semi-persistently scheduled, or the second CSI-RS may be non-periodically transmitted.

Optionally, the first CSI-RS and the second CSI-RS are both periodically transmitted, and the transmission period of the first CSI-RS is greater than the transmission period of the second CSI-RS, so that the number of times of switching the number of receiving antennas for measuring the first CSI-RS can be reduced, and the influence on downlink data transmission between the network device and the terminal device is reduced.

Optionally, the first CSI may be reported to the network device according to the second CSI reporting configuration.

Optionally, the second CSI reporting configuration may be associated with a second CSI resource configuration. The second CSI reporting configuration may include a time-domain behavior of CSI feedback, a measurement constraint configuration, CSI feedback parameters, and the like. Wherein the time-domain behavior of the CSI feedback includes configuring the CSI feedback as periodic, semi-continuous, or aperiodic CSI feedback.

With reference to the first aspect, in some implementation manners of the first aspect, the reporting, by the terminal device, the first CSI to the network device according to a result of measuring the second CSI-RS includes: the terminal equipment determines a first resource region, the resource size of the first resource region is larger than or equal to the resource occupied by the first PUCCH, and the first PUCCH bears CSI obtained by measuring the second CSI-RS by the terminal equipment according to the maximum receiving antenna number which can be used by the terminal equipment; and the terminal equipment transmits a second PUCCH on all or part of the first resource region, and the second PUCCH carries the first CSI.

Specifically, since the number of receiving antennas used by the terminal device may be different at different measurement occasions, resources occupied by the reported first CSI may be different, and time-frequency resources occupied by a PUCCH carrying the first CSI may be different. Therefore, the first resource region may be configured in advance, and a certain limit may be imposed on the size of the first resource region.

Optionally, the second PUCCH may also be used to carry CSI obtained by the terminal device measuring the second CSI-RS according to the maximum number of receiving antennas that the terminal device can use, that is, the size of the first PUCCH may be the same as that of the second PUCCH.

With reference to the first aspect, in some implementations of the first aspect, the first CSI includes a first RI value, and a maximum value of the first RI value is determined according to an RI limit value in a CSI report configuration used for reporting the first CSI and a number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device when measuring a CSI-RS corresponding to the first CSI.

In particular, it is considered that the value of RI cannot be greater than the number of receiving antennas, because if the number of layers of data transmitted by the network device is greater than the number of receiving antennas of the terminal device, the terminal device may have difficulty demodulating data transmitted by each layer of the network device due to interference of data transmitted by other layers. Therefore, the first RI value in the first CSI of the terminal device is the minimum value that cannot be greater than the RI limit value in the CSI report configuration used for reporting the first CSI and the number of receiving antennas used for receiving the PDSCH sent by the network device when measuring the CSI-RS corresponding to the first CSI.

With reference to the first aspect, in some implementations of the first aspect, the first CSI includes a first RI value, and a maximum value of the first RI value is a smaller value of an RI limit value in a CSI report configuration used for reporting the first CSI and a number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device when the terminal device measures a CSI-RS corresponding to the first CSI.

Optionally, the maximum value of the first RI value is an RI limit value in a CSI report configuration used for reporting the first CSI.

Optionally, the maximum value of the first RI value is the number of receiving antennas used for receiving the PDSCH sent by the network device when the terminal device measures the CSI-RS corresponding to the first CSI.

In a second aspect, a communication method is provided, which may be executed by a terminal device, or may also be executed by a chip or a circuit configured in the terminal device, and this application is not limited thereto.

Specifically, the method comprises the following steps: after the number of receiving antennas used by the terminal equipment for receiving the PDSCH sent by the network equipment changes, the terminal equipment determines first CSI, wherein the first CSI is CSI reported to the network equipment by the terminal equipment according to a first CSI report configuration, and the first CSI report configuration is associated with a first transmission scheme; and the terminal equipment receives the PDSCH sent by the network equipment according to the first CSI.

In this embodiment, after the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device changes, the terminal device may determine the first CSI and receive the PDSCH according to the first CSI.

Specifically, the first CSI is CSI reported by the terminal device to the network device according to the first CSI report configuration, and the first CSI report configuration is associated with the first transmission scheme. That is, the reporting parameter combination configuration included in the first CSI reporting configuration is associated with the first transmission scheme, and thus the parameter combination included in the first CSI is associated with the first transmission scheme.

Alternatively, the first transmission scheme may be a transmit diversity scheme.

Alternatively, the first transmission scheme may be an open loop transmission scheme or a semi-open loop transmission scheme.

Optionally, the first CSI report configuration includes a reporting parameter, where the reporting parameter is used to indicate a parameter combination cri-RI-i1-CQI or a parameter combination cri-RI-CQI.

The network device of the embodiment of the application performs downlink data transmission with the terminal device according to the first CSI, and the terminal device may also perform data reception according to a reception algorithm corresponding to the first CSI. Since the parameter combination included in the first CSI is associated with the first transmission scheme, the network device may perform downlink data scheduling with the terminal device through the first transmission scheme, where the first transmission scheme may be a transmit diversity scheme (e.g., an open-loop transmission scheme or a semi-open-loop transmission scheme), so that the requirement on accuracy of the CSI is low, and the network device may perform coarse precoding on the PDSCH according to the limited CSI, and then perform downlink data scheduling with the terminal device, thereby reducing adverse effects on data transmission due to mismatch between the used CSI and actual channel quality, and thus improving user experience.

With reference to the second aspect, in some implementations of the second aspect, the determining, by the terminal device, the first CSI includes: the terminal equipment determines the first CSI when the terminal equipment does not report the CSI to the network equipment according to the result of measuring the CSI-RS by the changed number of the receiving antennas and receives the PDCCH sent by the network equipment; the method for receiving the PDSCH sent by the network equipment by the terminal equipment according to the first CSI comprises the following steps: and the terminal equipment receives the PDSCH scheduled by the PDCCH according to the first CSI.

With reference to the second aspect, in some implementations of the second aspect, before the terminal device determines the first CSI, the method further includes: the terminal equipment reports the first CSI to the network equipment according to the first CSI report configuration; and the terminal equipment reports second CSI to the network equipment according to the second CSI report configuration, wherein the second CSI is associated with the second transmission scheme.

Optionally, the first transmission scheme is a transmit diversity scheme; and/or the second transmission scheme is a non-transmit diversity scheme.

Optionally, the first transmission scheme is an open loop transmission scheme or a semi-open loop transmission scheme.

Optionally, the reporting parameter in the second CSI reporting configuration is used to indicate one of the following CSI parameter combinations: cri-RI-PMI-CQI, cri-RI-i1, cri-RSRP, ssb-Index-RSRP, cri-RI-LI-PMI-CQI.

In a third aspect, a communication method is provided, which may be performed by a network device, or may also be performed by a chip or a circuit configured in the network device, and this is not limited in this application.

Specifically, the method comprises the following steps: after the number of receiving antennas used by the terminal equipment for receiving the PDSCH sent by the network equipment is changed, the network equipment determines first CSI according to the changed number of the receiving antennas, wherein the first CSI is CSI reported to the network equipment by the terminal equipment according to the result of measuring the CSI-RS by using the changed number of the receiving antennas; and the network equipment sends the PDSCH to the terminal equipment according to the first CSI.

With reference to the third aspect, in some implementations of the third aspect, the determining, by the network device, the first CSI according to the changed number of receiving antennas includes: when the terminal device does not report the CSI to the network device according to the result of measuring the CSI-RS by the changed number of the receiving antennas, and receives the PDCCH sent by the network device, the network device determines the first CSI according to the changed number of the receiving antennas; the method for the network equipment to send the PDSCH to the terminal equipment according to the first CSI comprises the following steps: and the network equipment sends the PDSCH scheduled by the PDCCH to the terminal equipment according to the first CSI.

With reference to the third aspect, in some implementations of the third aspect, the first CSI includes a first RI value, and the first RI value is determined according to an RI limit value in a CSI report configuration used for reporting the first CSI and a number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device when measuring a CSI-RS corresponding to the first CSI.

With reference to the third aspect, in some implementations of the third aspect, the first CSI includes a first RI value, and a maximum value of the first RI value is a smaller value of an RI limit value in a CSI report configuration used for reporting the first CSI and a number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device when the terminal device measures the CSI-RS corresponding to the first CSI.

In a fourth aspect, a communication method is provided, which may be executed by a network device, or may also be executed by a chip or a circuit configured in the network device, and this application is not limited thereto.

Specifically, the method comprises the following steps: when the number of receiving antennas used by the terminal equipment for receiving the PDSCH sent by the network equipment changes, the network equipment determines first CSI, wherein the first CSI is CSI reported to the network equipment by the terminal equipment according to a first CSI report configuration, and the first CSI report configuration is associated with a first transmission scheme; and the network equipment sends the PDSCH to the terminal equipment according to the first CSI.

With reference to the fourth aspect, in some implementations of the fourth aspect, the determining, by the network device, the first CSI includes: the method comprises the steps that the network equipment determines first CSI when the terminal equipment does not report the CSI to the network equipment according to the result of measuring the CSI-RS by the changed number of receiving antennas and receives the PDCCH sent by the network equipment; the method for the network equipment to send the PDSCH to the terminal equipment according to the first CSI comprises the following steps: and the network equipment sends the PDSCH scheduled by the PDSCH to the terminal equipment according to the first CSI.

With reference to the fourth aspect, in some implementations of the fourth aspect, before the network device determines the first CSI, the method further includes: the network equipment receives the first CSI reported by the terminal equipment according to the first CSI report configuration; and the network equipment receives the second CSI reported by the terminal equipment according to the second CSI report configuration, wherein the second CSI is associated with the second transmission scheme.

With reference to the fourth aspect, in some implementations of the fourth aspect, the first transmission scheme is a transmit diversity scheme; and/or the second transmission scheme is a non-transmit diversity scheme.

With reference to the fourth aspect, in certain implementations of the fourth aspect, the first transmission scheme is an open-loop transmission scheme or a semi-open-loop transmission scheme.

With reference to the fourth aspect, in some implementations of the fourth aspect, the reporting parameter in the first CSI reporting configuration is used to indicate one of the following CSI parameter combinations: cri-RI-i1-CQI, cri-RI-CQI; the reporting parameter in the second CSI reporting configuration is used to indicate one of the following CSI parameter combinations: cri-RI-PMI-CQI, cri-RI-i1, cri-RSRP, ssb-Index-RSRP, cri-RI-LI-PMI-CQI.

In a fifth aspect, a communication apparatus is provided, which may be a terminal device or a chip in the terminal device. The apparatus may include a processing unit and a transceiver unit. When the apparatus is a terminal device, the processing unit may be a processor, and the transceiving unit may be a transceiver; the terminal device may further include a storage unit, which may be a memory; the storage unit is used for storing instructions, and the processing unit executes the instructions stored by the storage unit to enable the terminal device to execute the method of the first aspect or the second aspect. When the device is a chip in a terminal device, the processing unit may be a processor, and the transceiving unit may be an input/output interface, a pin, a circuit, or the like; the processing unit executes instructions stored by a storage unit, which may be a storage unit within the chip (e.g., a register, a cache, etc.) or a storage unit external to the chip within the terminal device (e.g., a read-only memory, a random access memory, etc.), so as to cause the terminal device to perform the method of the first aspect or the second aspect.

In a sixth aspect, a communication apparatus is provided, where the apparatus may be a network device or a chip within the network device. The apparatus may include a processing unit and a transceiver unit. When the apparatus is a network device, the processing unit may be a processor, and the transceiving unit may be a transceiver; the network device may further include a storage unit, which may be a memory; the storage unit is configured to store instructions, and the processing unit executes the instructions stored by the storage unit to cause the network device to perform the method of the third aspect or the fourth aspect. When the apparatus is a chip in a network device, the processing unit may be a processor, and the transceiving unit may be an input/output interface, a pin, a circuit, or the like; the processing unit executes instructions stored by a storage unit (e.g., a register, a cache, etc.) within the chip or a storage unit (e.g., a read-only memory, a random access memory, etc.) external to the chip within the network device, so as to cause the network device to perform the method of the third or fourth aspect.

In a seventh aspect, a computer program product is provided, the computer program product comprising: computer program code which, when run on a computer, causes the computer to perform the method of the above-mentioned aspects.

It should be noted that, all or part of the computer program code may be stored in the first storage medium, where the first storage medium may be packaged together with the processor or may be packaged separately from the processor, and this is not specifically limited in this embodiment of the present application.

In an eighth aspect, a computer-readable medium is provided, which stores program code, which, when run on a computer, causes the computer to perform the method in the above-mentioned aspects.

Drawings

Fig. 1 shows a schematic diagram of a communication system suitable for use in embodiments of the present application.

Fig. 2 is a schematic diagram of a downlink time-frequency resource grid.

Fig. 3 is a schematic diagram of a physical layer processing procedure of a PDSCH.

Fig. 4 is a schematic diagram of association relationship between CSI configuration and CSI-RS configuration.

Fig. 5 is a schematic diagram of a relation between CSI-RS and CSI in a scenario where a terminal device switches the number of receiving antennas.

Fig. 6 is a schematic flowchart of an example of a communication method provided in the present application.

Fig. 7 is a schematic diagram of a specific example of the embodiment shown in fig. 6.

Fig. 8 is a schematic flowchart of another example of the communication method provided in the present application.

Fig. 9 is a schematic diagram of a specific example of the embodiment shown in fig. 8.

Fig. 10 is a schematic diagram of a communication apparatus according to an embodiment of the present application.

Fig. 11 is a schematic structural diagram of a terminal device according to an embodiment of the present application.

Fig. 12 is a schematic diagram of a communication device according to another embodiment of the present application.

Fig. 13 is a schematic structural diagram of a network device according to an embodiment of the present application.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

The technical scheme of the embodiment of the application can be applied to various communication systems, for example: a global system for mobile communications (GSM) system, a Code Division Multiple Access (CDMA) system, a Wideband Code Division Multiple Access (WCDMA) system, a General Packet Radio Service (GPRS), a Long Term Evolution (LTE) system, a LTE Frequency Division Duplex (FDD) system, a LTE Time Division Duplex (TDD), a universal mobile telecommunications system (universal mobile telecommunications system, UMTS), a Worldwide Interoperability for Microwave Access (WiMAX) communication system, a future fifth generation (5G) communication system, or a new radio access (NR) technology.

For the understanding of the embodiments of the present application, a communication system suitable for the embodiments of the present application will be described in detail with reference to fig. 1. Fig. 1 shows a schematic diagram of a suitable communication system suitable for use in embodiments of the present application. As shown in fig. 1, the communication system 100 may include at least one network device, such as the network device 110 shown in fig. 1; the communication system 100 may also include at least one terminal device, such as the terminal device 120 shown in fig. 1. Network device 110 and terminal device 120 may communicate via a wireless link. Each communication device, such as network device 110 or terminal device 120, may be configured with multiple antennas, which may include at least one transmit antenna for transmitting signals and at least one receive antenna for receiving signals. Additionally, each communication device can additionally include a transmitter chain and a receiver chain, each of which can comprise a plurality of components associated with signal transmission and reception (e.g., processors, modulators, multiplexers, demodulators, demultiplexers, antennas, etc.), as will be appreciated by one skilled in the art. Thus, network device 110 and terminal device 120 may communicate via multiple antenna techniques.

It should be understood that the network device in the wireless communication system may be any device having a wireless transceiving function. Such devices include, but are not limited to: evolved Node B (eNB or eNodeB), Radio Network Controller (RNC), Node B (Node B, NB), Base Station Controller (BSC), Base Transceiver Station (BTS), home base station (e.g., home evolved Node B or home Node B, HNB), baseband unit (BBU), Access Point (AP) in wireless fidelity (WIFI) system, wireless relay Node, wireless backhaul Node, Transmission Point (TP) or Transmission and Reception Point (TRP), etc., and may also be 5G, such as NR, gbb in the system, or transmission point (TRP or TP), one or a group of base stations in the 5G system may also be a panel of antennas, NB, or a panel of antennas, such as a baseband unit (BBU), or a Distributed Unit (DU), etc.

In some deployments, the gNB may include a Centralized Unit (CU) and a DU. The gNB may also include a Radio Unit (RU). A CU implements part of the function of a gNB, and a DU implements part of the function of the gNB, for example, the CU implements the function of a Radio Resource Control (RRC) layer, a Packet Data Convergence Protocol (PDCP) layer, and the DU implements the function of a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and a Physical (PHY) layer. Since the information of the RRC layer eventually becomes or is converted from the information of the PHY layer, the higher layer signaling, such as the RRC layer signaling, may also be considered to be transmitted by the DU or the DU + CU under this architecture. It is to be understood that the network device may be a CU node, or a DU node, or a device including a CU node and a DU node. In addition, the CU may be divided into network devices in a Radio Access Network (RAN), or may be divided into network devices in a Core Network (CN), which is not limited in this application.

It should also be understood that terminal equipment in the wireless communication system may also be referred to as User Equipment (UE), an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user equipment. The terminal device in the embodiment of the present application may be a mobile phone (mobile phone), a tablet computer (pad), a computer with a wireless transceiving function, a Virtual Reality (VR) terminal device, an Augmented Reality (AR) terminal device, a wireless terminal in industrial control (industrial control), a wireless terminal in self driving (self driving), a wireless terminal in remote medical (remote medical), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in smart city (smart city), a wireless terminal in smart home (smart home), and the like. The embodiments of the present application do not limit the application scenarios.

For the convenience of understanding the embodiments of the present application, first, the related art related to the present application will be briefly described.

Fig. 2 is a schematic diagram of a downlink time-frequency resource grid. As shown in fig. 2, in the communication system exemplified by the fifth generation wireless access system standard NR, a basic unit on the frequency domain is one subcarrier, and a subcarrier spacing (SCS) may be 15KHz, 30KHz, or the like. In the NR physical layer, a unit of an uplink or downlink frequency domain resource is a Physical Resource Block (PRB), and each PRB is composed of 12 consecutive subcarriers in the frequency domain.

As shown in fig. 2, each element on the resource grid is called a Resource Element (RE), and the RE is the smallest physical resource and includes one subcarrier in one Orthogonal Frequency Division Multiplexing (OFDM) symbol. The uplink time-frequency resource grid is similar to the downlink, and is not described here again. The basic time unit of downlink resource scheduling in NR is one slot (slot), and in general, one slot may be composed of 14 OFDM symbols in time.

It should be understood that fig. 2 is only an exemplary schematic diagram shown for describing physical resources, and does not limit the present application in any way.

The base station transmits a Physical Downlink Shared Channel (PDSCH) and a Physical Downlink Control Channel (PDCCH) for the terminal device. In order to correctly receive the PDSCH, the terminal device needs to demodulate the PDCCH first, and Downlink Control Information (DCI) carried by the PDCCH includes relevant information (such as PDSCH time-frequency resource location and size, multi-antenna configuration information, and the like) required for receiving the PDSCH.

Fig. 3 is a diagram illustrating a physical layer processing procedure of a PDSCH.

In fig. 3, data of the physical layer is organized in the form of Transport Blocks (TBs). One TB may be transmitted in one slot. If the terminal equipment does not support space division multiplexing, one slot at most sends one TB; if the terminal device supports space division multiplexing, at most 2 TBs will be transmitted in one slot. One codeword (codeword) is data obtained by performing CRC (cyclic redundancy check) insertion, code block segmentation, and CRC, channel coding, and rate matching for each code block for one TB transmitted in one slot. Each codeword corresponds to a TB, so that a terminal device transmits at most 2 codewords in one slot.

After layer mapping (layer mapping) is performed on complex symbols (modulation symbols) obtained after scrambling (scrambling) and modulation mapping (modulation mapping) are performed on 1 or 2 codewords, the complex symbols are mapped to one or more transmission layers (also commonly referred to as layers). Each layer corresponds to an active data stream. Precoding is a process of mapping a layer (layer) to an antenna port (antenna port) using a precoding matrix. The antenna port is a logical concept, and one antenna port may be one physical transmitting antenna or a combination of multiple physical transmitting antennas. In both cases, the receiver (receiver) of the terminal device does not resolve the signal from the same antenna port, because from the terminal perspective, whether the channel is formed by a single physical transmit antenna or by a combination of multiple physical transmit antennas, the Reference Signal (RS) corresponding to the antenna port defines the antenna port, and the terminal can obtain the channel estimate for the antenna port according to the reference signal. Each antenna port has its own reference signal, and the terminal needs to perform channel estimation and data demodulation according to the reference signal corresponding to the antenna port.

When the base station schedules downlink data for the terminal device, it needs to select downlink transmission configuration and related parameters, including Modulation and Coding Scheme (MCS), redundancy version (redundancy version), etc., based on real-time downlink channel conditions including interference conditions. To support downlink scheduling based on channel conditions, it is necessary for the terminal device to provide channel-state information (CSI) to the base station, and the base station may make a downlink data scheduling policy based on the CSI.

Channel state information is information reported by a receiving end (e.g., a terminal device) to a transmitting end (e.g., a network device) in a wireless communication system for describing channel properties of a communication link.

For example, the network device may send a channel-state information reference signal (CSI-RS) to the terminal device, and the terminal device may perform downlink channel measurement based on the CSI-RS sent by the network device to obtain CSI of a downlink channel and report the CSI to the network device, and the network device schedules downlink resources according to the CSI.

In NR, CSI includes, but is not limited to, various parameters such as a channel-quality indicator (CQI), a precoding-matrix indicator (PMI), a Rank Indicator (RI), a CSI-RS resource indicator (CRI), and a Layer Indicator (LI). It should be understood that the specific contents of the CSI listed above are only exemplary and should not be construed as limiting the present application in any way. The CSI may include one or more of the above listed items, and may also include other information for characterizing the CSI besides the above listed items, which is not limited in this application. Some of the parameters that will be referred to in the following of the present application are described below.

RI: an optimal number of layers for indicating downlink data transmission to the terminal device;

PMI: providing an indication of the best precoding matrix that can be employed given the number of layers indicated by the RI to the base station;

CQI: the highest MCS that can be employed to ensure that the bit error rate of downlink data reception does not exceed 10% with the proposed RI and PMI is indicated.

The precoding matrix proposed by the terminal device is not directly transmitted to the base station, but instead is an index number pointing to a certain matrix in a set of predefined matrices (called a codebook), and the terminal device selects the optimal precoding matrix from the set of matrices according to the number of antenna ports. In NR, a two-stage codebook form W ═ W is adopted₁W₂Wherein W is₁Represents some factors such as long term/wideband aspects of beamforming, and W₂Representing some property of the short-term/frequency selective sub-band, such as polarization properties, may be applied to W₁The beam in (2) is column selected and phase adjusted. In NR, two codebook types are defined, a Type I codebook and a Type II codebook, where the Type I codebook is CSI feedback of regular precision for link maintenance, i.e., single-user multiple-input multiple-output (SU-MIMO) transmission, and the Type II codebook is CSI feedback of high precision for multi-user multiple-input multiple-output (MU-MIMO) performance.

In practical applications, the base station may determine a technical scheme that can be supported in a transmission process, that is, a downlink transmission scheme, according to the CSI acquisition capability. In NR, the downlink transmission scheme includes a transmit diversity scheme (e.g., a semi-open loop transmission scheme, an open loop transmission scheme), a closed loop transmission scheme, a multi-user transmission scheme, and the like. In the present application, reference is primarily made to transmit diversity schemes, the meaning of which is described below:

for high-speed mobile systems and high-frequency-band shielding effects, since the channel changes rapidly and it is difficult for the base station to obtain accurate CSI in time, the base station may only be able to rely on limited CSI (e.g., the first-stage precoding matrix, i.e., W, of wideband feedback)₁) A coarse precoding is performed. Such a way of precoding based on the coarse CSI may be referred to as a transmit diversity scheme (e.g., a semi-open loop, open loop transmission scheme). At this time, the terminal device may assume W when calculating CQI₁Depending on the reported wideband PMI, W₂The selection is made randomly.

According to the downlink transmission scheme supported by the NR and the CSI reported by the terminal device, the NR supports various CSI parameter combinations reported by the terminal device, such as "cri-RI-PMI-CQI", "cri-RI-i 1", "cri-RI-i 1-CQI", "cri-RI-CQI", "cri-RI-LI-PMI-CQI", and the like, wherein the "cri-RI-PMI-CQI" parameter combination corresponds to a closed-loop transmission scheme, and the "cri-RI-i 1-CQI" and "cri-RI-CQI" parameter combination correspond to a transmit diversity scheme, and the meaning thereof is described below by taking "cri-RI-i 1-CQI" as an example:

when the terminal equipment is configured by the base station to report the CSI parameter combination 'cri-RI-i 1-CQI', the combination 'i 1' represents the first-level codebook in the two-level codebook. The terminal device reports a wideband PMI indication as an indication of a first-stage codebook in a two-stage codebook. The terminal device will report the CQI at a frequency granularity of precoding resource block groups (PRGs), each PRG may include one or more contiguous PRBs. Simultaneously precoding W for a second level codebook₂The terminal device assumes the precoding on each PRG of the PDSCH transmitted by the base station to be from N_pRandomly selected from the precoding (which can be seen as a transmit diversity scheme). Therefore, when calculating the CQI reported by each PRG, the terminal device needs to calculate the CQI according to the RI and W reportedW₁W₂To calculate a reported CQI value, where W₁That is, the precoding matrix indicated by the wideband PMI reported by the terminal equipment is determined according to the value i1, W₂Is then N_pA randomly selected one of the precodes.

In order to realize CSI reporting of a terminal device, a base station needs to configure N (N is greater than or equal to 1 and N is an integer) CSI reporting configurations (CSIreporting) for reporting different measurement results for each terminal device through a high-level signaling, and the NR standard is called "CSI-reportconfiguration".

The CSI reporting configuration may include configuration of the following parameters: codebook configuration, time-domain behavior of CSI feedback, frequency-domain granularity of CQI and PMI, measurement constraint configuration, CSI feedback parameters and the like.

Wherein the time-domain behavior of the CSI feedback includes configuring the CSI feedback as periodic (periodic), semi-continuous (semi-periodic) or aperiodic (aperiodic) CSI feedback. In NR, the CSI feedback parameter may be indicated by a signaling report quantity in the CSI configuration, where the signaling indicates a parameter combination included in the CSI reported by the terminal device, and the parameter combination may include, for example, the aforementioned parameter combinations such as "cri-RI-i 1-CQI" and "cri-RI-CQI".

The base station limits the range of the RI value reported by the terminal device according to the characteristics of the channel state and the type of the antenna array transmitting the data, which is called RI limitation (RI restriction) value. For example, for a Type I Codebook, when a base station antenna is a Single-antenna array (Single-Panel) (the Codebook is called a Type I Single-antenna Codebook), a CSI configuration includes a bitmap (bitmap) parameter Type I-Single-Panel-ri-recovery, which is a bit sequence r₇,...,r₁,r₀Each one of which is r_iCorresponding to a layer, when bit r_iWhen the value of (d) is 0, the PMI and RI reported by the terminal equipment will not match the value of r_iThe corresponding layers are correlated, so that the bit number of the bit sequence with the median value of 1 is the maximum value of the RI reported by the terminal equipment, namely the RI limit value. Other types of codebooks, such as Type I multi-antenna array Codebook (Type I multi-Panel Codebook), Type II Codebook (Type II Codebook), etc., also contain corresponding bitmapsThe parameters RI-recovery, typeII-RI-recovery indicate RI limit values.

In order to realize CSI reporting of the terminal device, the base station also needs to configure M (M is greater than or equal to 1 and M is an integer) CSI resource configurations (CSI resource setting) for each terminal device through high-layer information, and the NR standard is called "CSI-ResourceConfig".

For CSI resource configuration, each CSI resource configuration may include S (S ≧ 1 and S is an integer) CSI resource sets (CSI resource sets), each CSI resource set includes K (K ≧ 1 and K is an integer) CSI-RS resources, which may be non-zero-power (NZP) CSI-RS or CSI interference measurement (CSI-IM). Wherein the parameter resourceType in the CSI resource configuration is used to indicate the Time domain behavior (Time domain behaviour) of all CSI-RS resources contained therein, i.e. the configuration of periodic, semi-persistent and aperiodic.

Each CSI reporting configuration is associated with one or more CSI resource configurations for channel and interference measurement and reporting, that is, the reporting result of the CSI reporting configuration of each terminal device is obtained by the terminal device according to the measurement of the CSI-RS resource of the associated CSI resource configuration, as shown in fig. 4.

Fig. 4 is a schematic diagram of an association relationship between CSI reporting configuration and CSI resource configuration.

In fig. 4, two CSI reporting configurations, including CSI reporting configuration #1 and CSI reporting configuration #2, include three CSI resource configurations, including CSI resource configuration #1, CSI resource configuration #2 and CSI resource configuration #3, where CSI-RS resources included in CSI resource configuration #1 and CSI resource configuration #3 are nzp CSI-RS, and CSI-RS resources included in CSI resource configuration #2 are CSI-IM.

Further, CSI reporting configuration #1 may be associated with CSI resource configuration #1, CSI resource configuration #2, CSI resource configuration #3, and CSI reporting configuration #2 may be associated with CSI resource configuration # 1.

It should be understood that the above descriptions of the CSI reporting configuration and the CSI resource configuration are only for facilitating understanding of the technical solutions of the present application, and do not limit the present application in any way.

In a communication system, since the battery capacity of a terminal device is limited, how to reduce the power consumption of the terminal device is one of the concerns in the industry. A way to reduce the energy consumption of a terminal device is currently provided. The method is based on the phenomenon that the energy consumed by the receiving antennas of the terminal equipment is different when the number of the receiving antennas of the terminal equipment is different, so that the number of the receiving antennas of the terminal equipment can be dynamically changed along with the change of the actual communication situation. The network device may instruct the terminal device to switch the receiving antennas by a display signaling or an implicit method, for example, the network device may instruct the terminal device to use a smaller number of receiving antennas to communicate with the network device when the channel state is better or the amount of data to be transmitted is smaller. When the channel state is poor or the amount of data to be transmitted is large, the network device may instruct the terminal device to use a large number of receiving antennas to communicate with the network device. Therefore, the energy consumption of the terminal equipment can be reduced while the data is ensured to be correctly and reliably received. The receiving antenna of the terminal device may be considered herein as a receiving antenna used for receiving the PDSCH.

Based on the scenario that the number of receiving antennas is switched by the terminal device, the current CSI measurement and reporting mechanism may not be reasonable enough, and the accuracy of scheduling or data transmission by the network device may be affected within a period of time after the number of receiving antennas is switched.

Fig. 5 is a schematic diagram of a relation between CSI-RS and CSI in a scenario where a terminal device switches the number of receiving antennas. In fig. 5, a network device first configures at least one CSI resource configuration (e.g., including CSI resource configuration #1) for a terminal device through higher layer signaling (e.g., Radio Resource Control (RRC) message), where the CSI resource configuration #1 includes a plurality of CSI-RS resources, which may be configured periodically, semi-continuously, or aperiodically, and the terminal device receives the plurality of CSI-RS according to time domain behaviors of the CSI-RS resources indicated in the CSI resource configuration #1, performs measurement, and finally reports CSI to the network device according to a measurement result. For example, in fig. 5, the terminal device receives one CSI-RS at time 0 and time 2, respectively, measures the CSI-RS, generates corresponding CSI according to the measurement result, and reports the CSI to the network device at time 1 and time 3.

In fig. 5, the terminal device may report the CSI according to CSI reporting configuration #1 pre-configured by the network device. Specifically, the CSI reporting configuration #1 may be associated with the CSI resource configuration #1, and the terminal device obtains a result according to measurement on the CSI-RS resource in the CSI resource configuration #1, and reports a corresponding measurement result to the network device according to the CSI reporting configuration # 1.

The CSI reporting configuration #1 may include parameters related to a time domain behavior of CSI feedback, and the time domain behavior of CSI feedback may include configuring the CSI feedback as periodic, semi-continuous, or aperiodic CSI feedback. In addition, the CSI reporting configuration #1 may further include configurations such as CSI feedback parameters.

In fig. 5, the network device may periodically transmit CSI-RS to the terminal device (e.g., transmit CSI-RS at time 0, 2, 6, and 8 spaced by the same time), the terminal device receives the CSI-RS and performs measurement, and simultaneously periodically feedback CSI to the network device (e.g., feedback CSI at time 1, 3, 7, and 9 spaced by the same time). At time 4, the terminal device needs to switch the number of receiving antennas from 2Rx to 4Rx for some reason, and during the period from time 4 to time 7 after switching, since the terminal device has not reported the latest CSI for 4Rx yet, but the network device may need to perform downlink data transmission during this period, according to the current protocol, the network device may perform downlink data scheduling according to the CSI for 2Rx reported before switching (referred to as CSI #1, for example, the CSI #1 may be the CSI reported at time 3), and the terminal device may perform data reception according to the CSI #1, which may cause a problem at this time, and the current real channel quality and the CSI #1 may not match, thereby affecting the accuracy of network device scheduling or data transmission.

As an example, as shown in fig. 5, time 5 is a time between time 4 and time 7, at time 5, the network device transmits PDCCH scheduling PDSCH to the terminal device, and between time 4 and time 5, the terminal device does not report CSI for 4Rx, so the network device may transmit PDSCH scheduled by PDCCH according to CSI reported at time 3 before handover, and the terminal device receives PDSCH according to CSI reported at time 3. It is easy to understand that the CSI reported at time 3 is for 2Rx, and at this time, the number of receiving antennas becomes 4Rx, and the current channel quality may not match the CSI reported at time 3, thereby affecting the accuracy of scheduling or data transmission between the network device and the terminal device.

In order to avoid the above problem, the present application provides a communication method. As will be described below in connection with fig. 6 and 7.

Fig. 6 is a schematic flow chart of a communication method 200 according to an embodiment of the present application. The method 200 shown in fig. 6 includes steps 201 to 230.

In step 210, after the number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device changes, the network device determines a first CSI according to the changed number of receiving antennas, where the first CSI is a CSI reported by the terminal device to the network device according to a result of measuring the CSI-RS by using the changed number of receiving antennas;

in step 220, after the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device changes, the terminal device determines the first CSI according to the changed number of receiving antennas;

in step 230, the network device transmits PDSCH to the terminal device according to the first CSI.

Accordingly, in step 230, the terminal device receives the PDSCH transmitted by the network device according to the first CSI.

The number of receiving antennas used by the terminal device (e.g., the number of receiving antennas receiving the PDSCH transmitted by the network device) may vary based on considerations such as power saving. For example, the number of receiving antennas used by the terminal device may be increased or decreased according to the size of the data amount to be transmitted or the channel state condition.

In this embodiment, after the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device changes, both the network device and the terminal device determine the first CSI according to the changed number of receiving antennas, and the network device transmits the PDSCH to the terminal device according to the first CSI, and the terminal device receives the PDSCH according to the first CSI.

The first CSI and the changed number of the receiving antennas have a corresponding relation. Specifically, the first CSI is CSI reported by the terminal device to the network device, and the terminal device receives the CSI-RS with the changed number of receiving antennas, measures the CSI-RS, generates and reports the CSI to the network device according to a measurement result.

Or in other words, the terminal device receives the CSI-RS with the changed number of receiving antennas, measures the CSI-RS, generates and reports at least one CSI to the network device according to a measurement result, and the network device and the terminal device may determine one of the at least one CSI as the first CSI. As will be readily appreciated, the protocol may specify that the first CSI determined by the network device and the terminal device is the same CSI.

The network device transmits downlink data to the terminal device according to the first CSI, and the terminal device may also receive data according to a receiving algorithm corresponding to the first CSI. Because the first CSI used by the network equipment and the terminal equipment has a corresponding relation with the current receiving antenna quantity, and the first CSI is matched with the current real channel quality, after the receiving antenna quantity of the terminal equipment changes, the network equipment can perform downlink data scheduling with the terminal equipment by using the more accurate CSI, so that the use experience of a user is improved.

For understanding the present embodiment, before further describing the above steps 210 to 230, a specific process of the terminal device receiving the CSI-RS and reporting the CSI will be described below with reference to fig. 6 and fig. 7.

The network device may transmit the resource configuration information of the CSI-RS, such as the CSI resource configuration listed above, to the terminal device through higher layer signaling (e.g., RRC message) in advance. The terminal device may determine the CSI-RS resource according to the CSI resource configuration. Then, the terminal device may receive the CSI-RS based on the CSI-RS resource and complete the measurement, and report the CSI to the network device according to the measurement result.

In this embodiment, the CSI resource configuration includes a first CSI resource configuration and a second CSI resource configuration.

The terminal device can only receive and measure the first CSI-RS in the first CSI-resource configuration by the first number of receiving antennas, and cannot receive and measure the first CSI-RS in the first CSI-resource configuration by other numbers of receiving antennas. If the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device is not the first number of receiving antennas when performing measurement (receiving the first CSI-RS in the first CSI resource configuration), the terminal device should switch the number of receiving antennas to the first number of receiving antennas in advance, and then receive and measure the first CSI-RS. The higher layer signaling may configure its associated terminal device receive antenna number when configuring the first CSI resource configuration.

For example, assuming that the number of receiving antennas that can be used by the terminal device is 1Rx, 2Rx, 4Rx, the first number of receiving antennas may be any one of 1Rx, 2Rx, 4 Rx.

The second CSI resource configuration is associated with the number of receiving antennas (or the number of currently used receiving antennas) used by the terminal device to receive the PDSCH transmitted by the network device when performing the measurement. And the terminal equipment receives and measures the second CSI-RS in the second CSI resource configuration by using the number of receiving antennas for receiving the PDSCH sent by the network equipment during measurement.

The CSI resource configuration #1 in the foregoing description related to fig. 5 may be taken as an example of the second resource configuration of the present embodiment. Specifically, in fig. 5, the terminal device measures the CSI-RS resources in CSI resource configuration #1 at time 0, 2, 6, and 8 respectively according to CSI resource configuration #1, and this CSI resource configuration #1 is associated with the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device when the measurement is made, that is, at time 0, 2, and 8, the terminal device will measure the CSI-RS resources at the currently used 2Rx, and at time 6, the terminal device will measure the CSI-RS resources at the currently used 4 Rx.

The first CSI resource configuration may include parameters related to the time domain behavior of the first CSI-RS being transmitted, and the second CSI resource configuration may include parameters related to the time domain behavior of the second CSI-RS being transmitted.

Based on the foregoing description of the first CSI resource configuration and the second CSI resource configuration, the following proceeds to describe the communication method 200 according to the embodiment of the present application with reference to fig. 6. The method 200 further comprises:

in step 201, the network device sends a first CSI-RS in the first CSI resource configuration to the terminal device.

Accordingly, in step 201, the terminal device determines a first number of receiving antennas according to the first CSI resource configuration, and measures the first CSI-RS in the first CSI resource configuration sent by the network device with the first number of receiving antennas.

In step 202, the terminal device reports CSI #1 to the network device according to the measurement result of the first CSI-RS.

Accordingly, in step 202, the network device receives CSI #1 reported by the terminal device.

Specifically, referring to the related expressions above, the first CSI resource configuration in the present embodiment is associated with the first number of receive antennas. The terminal device may determine, according to the first CSI resource configuration, the number of first receiving antennas, measure the first CSI-RS sent by the network device by using the number of first receiving antennas, and then report CSI #1 to the network device according to a measurement result, where the CSI #1 is CSI for which the receiving antennas are the number of first receiving antennas.

It is easy to understand that, when performing the measurement, if the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device is not the first number of receiving antennas, the terminal device should also switch the number of receiving antennas to the first number of receiving antennas in advance, so as to be able to receive and measure the first CSI-RS with the first number of receiving antennas.

Specifically, the terminal device may determine, first, the number of receiving antennas used for receiving the PDSCH transmitted by the network device when performing measurement, and determine whether the number of receiving antennas used for receiving the PDSCH transmitted by the network device when performing measurement is the first number of antennas, and if not, the terminal device may switch the number of receiving antennas to the first number of receiving antennas in advance according to the time-domain behavior for transmitting the first CSI-RS indicated by the first CSI resource configuration.

Optionally, in order to reduce the influence on the downlink data transmission, after the measurement is completed, the terminal device may switch the number of receiving antennas from the first number of receiving antennas back to the original number of receiving antennas for receiving the PDSCH transmitted by the network device.

Specifically, in step 202, the terminal device reports CSI #1 to the network device according to the measurement result of the first CSI-RS, and the terminal device may report the CSI #1 to the terminal device using the first CSI report configuration.

The first CSI reporting configuration may be associated with a first CSI resource configuration. The first CSI reporting configuration may include a time-domain behavior of CSI feedback, a measurement constraint configuration, CSI feedback parameters, and the like. Wherein the time-domain behavior of the CSI feedback includes configuring the CSI feedback as periodic, semi-continuous, or aperiodic CSI feedback.

Optionally, the first CSI reporting configuration further includes an RI limit value.

Optionally, the CSI #1 includes a first RI value therein.

In particular, it is considered that the value of RI cannot be greater than the number of receiving antennas, because if the number of layers of data transmitted by the network device is greater than the number of receiving antennas of the terminal device, the terminal device may have difficulty demodulating data transmitted by each layer of the network device due to interference of data transmitted by other layers. Therefore, the first RI value in the CSI #1 reported by the terminal device is the minimum value that cannot be greater than the RI limit value in the first CSI resource configuration and the number of receiving antennas (i.e., the number of first receiving antennas) used for receiving the PDSCH transmitted by the network device when the first CSI-RS is measured.

Optionally, the first RI value may be determined according to the RI limit value and the first number of receive antennas.

Alternatively, the maximum value of the first RI value may be the smaller value of the RI limit value and the number of first receiving antennas. For example, the maximum value of the first RI value may be the RI limit value or the first number of receiving antennas.

In step 203, the network device sends the second CSI-RS in the second CSI resource configuration to the terminal device.

Accordingly, in step 203, the terminal device measures the second CSI-RS in the second CSI resource configuration sent by the network device by using a second number of receiving antennas, where the second number of receiving antennas is the number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device when the measurement is performed.

In step 204, the terminal device reports CSI #2 to the network device according to the measurement result of the second CSI-RS.

Accordingly, in step 202, the network device receives CSI #2 reported by the terminal device.

Specifically, referring to the related expression in the foregoing, the second CSI resource configuration in this embodiment is associated with the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device when performing measurement. When the measurement is performed, the number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device is the second number of receiving antennas, so that the terminal device measures the second CSI-RS sent by the network device according to the second number of receiving antennas, and then reports CSI #2 to the network device according to the measurement result, where the CSI #2 is the CSI for the second number of receiving antennas for the receiving antennas.

Specifically, in step 202, the terminal device reports CSI #2 to the network device according to the measurement result of the second CSI-RS, and the terminal device may report the CSI #2 to the terminal device using the second CSI reporting configuration.

The second CSI reporting configuration may be associated with a second CSI resource configuration. Similar to the first CSI reporting configuration, the second CSI reporting configuration may include a time-domain behavior of CSI feedback, a measurement constraint configuration, CSI feedback parameters, and the like.

Optionally, the time-domain behavior of the CSI feedback includes configuring the CSI feedback as periodic, semi-continuous, or aperiodic CSI feedback.

In NR, a PUCCH (physical uplink control channel) may be used to carry periodic or semi-persistent CSI, while resource allocation of the PUCCH carrying CSI is semi-statically configured. That is, the higher layer signaling directly configures a PUCCH resource, and configures a period and an offset within the period for the resource, so that the resource is periodically available. Some other information may also be configured, such as: the starting symbol index of the PUCCH in the slot, the time domain duration, the index of the starting PRB, the number of occupied PRBs, etc.

For CSI #2 reporting configured by the second CSI report configuration, the reporting may be periodic or semi-persistent, so that one PUCCH resource may be semi-statically configured to carry CSI # 2. However, the size of the resource occupied by CSI #2 corresponding to the second CSI reporting configuration is related to the number of Rx antennas when the terminal device measures the CSI-RS. When the number of Rx antennas of the terminal device is different, and the number of information bits of CSI #2 is different, the time-frequency resources occupied by the PUCCH carrying CSI #2 may be different.

Optionally, the network device may pre-configure a first resource region, where the resource size of the first resource region is greater than or equal to the resource occupied by the first PUCCH, and the first PUCCH carries CSI obtained by the terminal device measuring the second CSI-RS according to the maximum number of receiving antennas that the terminal device can use.

Specifically, since the number of receiving antennas used by the terminal device may be different at different measurement occasions, resources occupied by the reported CSI #2 may be different, and time-frequency resources occupied by the PUCCH carrying the CSI #2 may be different. Therefore, the first resource region may be configured in advance, and a certain limit may be imposed on the size of the first resource region.

The terminal device may first determine the first resource region and transmit a second PUCCH on all or part of the first resource region, the second PUCCH carrying the CSI # 2.

Optionally, if the resource occupied by the second PUCCH is smaller than the first resource region, the network device may allocate the remaining resource of the first resource region to other terminal devices, so as to improve the PUCCH resource utilization efficiency.

Optionally, the second CSI reporting configuration further includes an RI limit value.

Optionally, the CSI #2 includes a first RI value therein.

Similarly, it is considered that the value of RI cannot be larger than the number of receiving antennas, because if the number of layers of data transmitted by the network device is larger than the number of receiving antennas of the terminal device, the terminal device may have difficulty demodulating data transmitted by each layer of the network device due to interference of data transmitted by other layers. Therefore, the first RI value in the CSI #2 sent by the terminal device is the minimum value that cannot be greater than the RI limit value in the second CSI resource configuration and the number of receiving antennas (i.e., the second number of receiving antennas) for receiving the PDSCH sent by the network device when the second CSI-RS is measured. The terminal device may determine the first RI value according to a minimum value between the RI limit value and the number of second receiving antennas.

It is easy to understand that the second number of receiving antennas is the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device when performing measurement, and therefore the value of the second number of receiving antennas may vary with different measurement occasions. For example, the second number of receiving antennas may be greater than, less than, or equal to the RI limit value, depending on the measurement occasion.

Optionally, the first RI value may be determined according to the RI limit value and the number of second receive antennas.

Alternatively, the maximum value of the first RI value may be the smaller value of the RI limit value and the number of second receiving antennas. For example, the maximum value of the first RI value may be the RI limit value or the second number of receiving antennas.

As described above, the first CSI-RS and the second CSI-RS may each include a plurality of CSI-RS, and accordingly, the CSI #1 and the CSI #2 may each include a plurality of CSI, it being understood that the first CSI-RS and the CSI #1 are CSI-RS and CSI configured for the first CSI resource, and the second CSI-RS and the CSI #2 are CSI-RS and CSI configured for the second CSI resource, with the difference, as described above, being mainly that: for the first CSI resource configuration, the terminal device measures the CSI-RS with the number of receiving antennas determined according to the first CSI resource configuration to obtain CSI, where the number of receiving antennas may be exactly the same as the number of receiving antennas used for receiving the PDSCH during measurement, but is not limited to the number of receiving antennas used for receiving the PDSCH; for the second CSI resource configuration, the terminal device measures the CSI-RS with the number of receiving antennas used for receiving the PDSCH in the measurement to obtain the CSI.

It should be understood that the first and second numbers of receive antennas are terms used for convenience in expressing the number of receive antennas used in the measurement of the first and second CSI-RSs, and are not used for specific values (e.g., 2Rx, 4Rx) for expressing two different numbers of receive antennas. When the second CSI-RS includes a plurality of CSI-RSs, since the number of receiving antennas used to receive the PDSCH may be different when measuring the respective CSI-RSs, the second number of receiving antennas may also be different from each other for the respective CSI-RSs. Although the first and second numbers of receiving antennas are different in concept, the specific values of the actually referred number of receiving antennas may be the same, for example, assuming that in fig. 5, the first CSI-RS is measured at time 0, and the number of receiving antennas determined according to the first CSI resource configuration is 4Rx, so that the first number of receiving antennas is 4Rx for the first CSI-RS at time 0, and the second CSI-RS is measured at time 6, where the number of receiving antennas used for receiving PDSCH is 4Rx, so that the second number of receiving antennas is 4Rx for the second CSI-RS at time 6.

In combination with the above analysis, in steps 210 to 230, the terminal device and the network device may determine a CSI (CSI #1 and/or CSI #2) of one or more CSIs as a first CSI, where the number of receiving antennas corresponding to the CSI (i.e., the number of receiving antennas used in a measurement process of measuring a CSI-RS to obtain the CSI) is the changed number of receiving antennas.

Optionally, CSI reported last time before the number of receiving antennas receiving the PDSCH transmitted by the network device changes among the CSI may be determined as the first CSI. In addition, the CSI reported by the other frequency such as the last but one time may also be determined as the first CSI, which is not limited in the present application.

Further, in step 210, the network device determines the first CSI according to the changed number of receiving antennas when the terminal device has not reported the CSI to the network device according to the result of measuring the CSI-RS by the changed number of receiving antennas and receives the PDCCH sent by the network device.

In step 220, the terminal device determines the first CSI according to the changed number of receiving antennas, when the terminal device has not reported CSI to the network device according to the result of measuring the CSI-RS by the changed number of receiving antennas and receives the PDCCH sent by the network device.

In step 230, the network device sends the PDSCH scheduled by the PDCCH to the terminal device according to the first CSI.

Accordingly, in step 230, the terminal device receives the PDSCH scheduled by the PDCCH according to the first CSI. That is, the terminal device assumes that the network device determines the PDSCH scheduled by the PDCCH according to the first CSI.

Specifically, after the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device is changed, and in the period of time when the PDCCH transmitted by the network device is received, if the terminal device does not report the CSI (including CSI #1 and/or CSI #2) to the network device according to the result of measuring the CSI-RS (including the first CSI-RS and/or the second CSI-RS) by using the changed number of receiving antennas, the terminal device and the network device may determine the first CSI according to the changed number of receiving antennas, and transmit the PDSCH scheduled by the PDCCH according to the first CSI.

Optionally, after the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device changes, and in the period of time when the PDCCH transmitted by the network device is received, if the terminal device reports the CSI (including CSI #1 and/or CSI #2) to the network device according to the result of measuring the CSI-RS (including the first CSI-RS and/or the second CSI-RS) by using the changed number of receiving antennas, data transmission may be performed between the network device and the terminal device according to the reported CSI at this time.

To facilitate understanding of the communication method 200 provided in the embodiments of the present application, the method 200 will be described with reference to specific examples. Fig. 7 is a schematic diagram of a specific example of the communication method 200 provided in this application, in fig. 7, the terminal device may receive downlink data transmitted by the network device by using 2Rx (where Rx represents a receiving antenna of the terminal device) and 4Rx, and the number of used receiving antennas may be changed, for example, at time 4, the number of used receiving antennas of the terminal device is changed from 2Rx to 4 Rx.

In fig. 7, the first number of receive antennas may be 4Rx, and thus the first CSI resource configuration may be associated with the number of receive antennas of 4Rx, that is, the terminal device may only measure the first CSI-RS in the first CSI resource configuration by the number of receive antennas of 4Rx, and may not use other numbers of receive antennas (e.g., 2Rx) to measure the first CSI-RS.

At time 0 and time 10, the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device is 2Rx, the terminal device should switch the number of receiving antennas to 4Rx in advance, and measure the first CSI-RS transmitted by the network device at time 0 and time 10 with 4 Rx. In order to reduce the influence on downlink data transmission, after the measurement of the first CSI-RS is completed, the terminal device may switch the number of receiving antennas from 4Rx back to the previous 2 Rx.

And the second CSI resource configuration is associated with the number of receive antennas used by the terminal device to receive the PDSCH transmitted by the network device when the measurement is made. And the terminal equipment measures the second CSI-RS in the second CSI resource configuration according to the number of receiving antennas for receiving the PDSCH sent by the network equipment during measurement. Specifically, at time 2 and time 8, the terminal device may measure the second CSI-RS at the current 2Rx, and at time 6, the terminal device may measure the second CSI-RS at 4 Rx.

In fig. 7, the first CSI-RS and the second CSI-RS are both periodically transmitted, and the transmission period of the first CSI-RS is greater than the transmission period of the second CSI-RS, so that the number of times of switching the number of receiving antennas for measuring the first CSI-RS can be reduced, and the influence on downlink data transmission between the network device and the terminal device is reduced.

In fig. 7, the terminal device measures the first CSI-RS transmitted by the network device at time 0 with 4Rx, and reports CSI #1 to the network device at time 1 according to the measurement result.

Similarly, the terminal device measures, at 2Rx, the second CSI-RS transmitted by the network device at time 2 and time 8, and reports CSI #2 to the network device at time 3 and time 9 according to the measurement result. The terminal device measures the second CSI-RS transmitted by the network device at time 6 with 4Rx, and reports CSI #2 to the network device at time 7 according to the measurement result.

The terminal device may periodically report CSI #1 and CSI #2 to the network device according to the first CSI report configuration and the second CSI report configuration, respectively, where the first CSI report configuration and the second CSI report configuration may include an RI limit value, for example, the RI limit value may be 4.

The CSI #1 and the CSI #2 each include a first RI value, and a maximum value of the first RI value may be a smaller value of the RI limit value and the number of receiving antennas used for receiving the PDSCH transmitted by the network device when the terminal device measures the first CSI-RS or the second CSI-RS.

Thus, for the first CSI reported at time 1, it includes a first RI value of no greater than 2.

For the second CSI reported at time 3 and time 9, the first RI value included therein is not greater than 2.

For the second CSI reported at time 7, it includes a first RI value of no greater than 4.

At time 4 in fig. 7, the number of receiving antennas used by the terminal device is switched from 2Rx to 4 Rx. At time 5, the terminal device receives the PDCCH sent by the network device, and during the period between time 4 and time 5, the terminal device has not reported CSI to the network device according to the result of measuring the CSI-RS by the changed number of receiving antennas (i.e., 4Rx), at this time, the terminal device and the network device may determine the first CSI according to 4Rx, may determine CSI #1 reported by the terminal device at time 1 as the first CSI, and the network device may send the PDSCH scheduled by the PDCCH according to CSI #1 reported at time 1, and at the same time, the terminal device may receive the PDSCH scheduled by the PDCCH according to CSI #1 reported at time 1.

It is easy to understand that, since the CSI #1 reported at time 1 is compared and matched with the current real channel quality, after the number of receiving antennas of the terminal device changes, the network device can perform downlink data scheduling with the terminal device using the more accurate CSI, thereby improving the user experience.

Optionally, if, in the period between time 4 and time 5, the terminal device has reported CSI (whether CSI #1 or CSI #2) to the network device according to the result of measuring the CSI-RS by 4Rx, the PDSCH scheduled by the PDCCH may be transmitted between the network device and the terminal device according to the reported CSI at this time.

In addition, at time 7, the terminal device reports CSI #2 to the network device according to the result of measuring the second CSI-RS by the 4Rx, and after time 7, the PDSCH scheduled by the PDCCH may be transmitted between the network device and the terminal device according to CSI #2 reported at time 7.

Fig. 8 is a schematic flow chart diagram of a communication method 300 of an embodiment of the present application. The method 300 shown in fig. 8 includes steps 301 to 330.

In step 310, after the number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device changes, the network device determines a first CSI, where the first CSI is a CSI reported by the terminal device to the network device according to a first CSI report configuration, and the first CSI report configuration is associated with the first transmission scheme.

In step 320, after the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device changes, the terminal device determines the first CSI.

In step 330, the network device transmits the PDSCH to the terminal device according to the first CSI.

Accordingly, in step 330, the terminal device receives the PDSCH transmitted by the network device according to the first CSI.

In this embodiment, after the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device changes, both the network device and the terminal device determine the first CSI, and the network device transmits the PDSCH to the terminal device according to the first CSI, and the terminal device receives the PDSCH according to the first CSI.

Before the terminal device and the network device determine the first CSI, the method 300 further includes:

in step 301, the terminal device reports the first CSI to the network device according to the first CSI reporting configuration.

Accordingly, in step 301, the network device receives the first CSI reported by the terminal device.

In step 302, the terminal device reports the second CSI to the network device according to the second CSI reporting configuration.

Accordingly, in step 302, the network device receives the second CSI reported by the terminal device.

Specifically, before the terminal device and the network device determine the first CSI, the terminal device first reports the first CSI and the second CSI to the network device according to the first CSI reporting configuration and the second CSI reporting configuration, which are easily understood to be determined by the terminal device according to the measurement result of the CSI-RS. Wherein the first CSI reporting configuration is associated with a first transmission scheme and the second CSI reporting configuration may be associated with a second transmission scheme.

Alternatively, the second transmission scheme may be a non-transmit diversity scheme.

Alternatively, the second transmission scheme may be any one of a closed-loop transmission scheme, a multi-user transmission scheme, and the like.

Optionally, the second CSI report configuration includes a reporting parameter, where the reporting parameter is used to indicate one of the following parameter combinations: cri-RI-PMI-CQI, cri-RI-i1, cri-RSRP, ssb-Index-RSRP, cri-RI-LI-PMI-CQI.

I.e. the second transmission scheme is different from the first transmission scheme.

In combination with the above analysis, in steps 310 to 330, after the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device changes, the terminal device and the network device may determine the first CSI, and the network device transmits the PDSCH to the terminal device according to the first CSI, and the terminal device receives the PDSCH transmitted by the network device according to the first CSI.

Optionally, if the first CSI includes a plurality of CSI, data transmission may be performed between the network device and the terminal device according to the last reported first CSI. In addition, data transmission may also be performed between the network device and the terminal device according to the first CSI reported by the last but one other frequency, which is not limited in this application.

Further, in step 310, the network device determines the first CSI if the terminal device has not reported the CSI to the network device according to the result of measuring the CSI-RS by the changed number of receiving antennas, and receives the PDCCH sent by the network device.

In step 320, the terminal device determines the first CSI if the terminal device has not reported CSI to the network device according to the result of measuring the CSI-RS by the changed number of receiving antennas, and receives the PDCCH sent by the network device.

In step 330, the network device sends the PDSCH scheduled by the PDCCH to the terminal device according to the first CSI.

Accordingly, in step 330, the terminal device receives the PDSCH scheduled by the PDCCH according to the first CSI.

Specifically, after the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the network device changes, and in the period of time when the PDCCH transmitted by the network device is received, if the terminal device does not report CSI (including the first CSI and the second CSI) to the network device according to the result of measuring the CSI-RS by using the changed number of receiving antennas, the terminal device and the network device may determine the first CSI, and transmit the PDSCH scheduled by the PDCCH according to the first CSI.

Optionally, after the number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device changes, and in a period of time when the PDCCH sent by the network device is received, if the terminal device reports CSI (including the first CSI and the second CSI) to the network device according to a result of measuring the CSI-RS by using the changed number of receiving antennas, data transmission may be performed between the network device and the terminal device according to the reported CSI at this time.

For example, if the terminal device reports the first CSI to the network device according to the result of measuring the CSI-RS by using the changed number of the receiving antennas in the time period, data transmission may be performed between the network device and the terminal device according to the first CSI.

For another example, if the terminal device reports the second CSI to the network device according to the result of measuring the CSI-RS by using the changed number of the receiving antennas in the time period, data transmission may be performed between the network device and the terminal device according to the second CSI.

To facilitate understanding of the communication method 300 provided in the embodiments of the present application, the method 300 will be described with reference to specific examples. Fig. 9 is a schematic diagram of a specific example of a communication method 300 provided in this application, in fig. 9, a terminal device may use 2Rx and 4Rx to receive downlink data sent by a network device, and the number of used receiving antennas may be changed, for example, at time 4, the number of used receiving antennas of the terminal device is changed from 2Rx to 4 Rx.

In fig. 9, the terminal device reports the first CSI to the network device periodically according to the first CSI report configuration, and the terminal device reports the second CSI to the network device periodically according to the second CSI report configuration. And the first CSI reporting configuration is associated with a first transmission scheme, which may be a transmit diversity scheme. The second CSI reporting configuration is associated with a second transmission scheme, which may be a non-transmit diversity scheme (e.g., a closed-loop transmission scheme).

Specifically, the terminal device reports the first CSI to the network device at time 0 and time 5, and reports the second CSI to the network device at time 1 and time 4, respectively.

At time 2 in fig. 9, the number of receiving antennas used by the terminal device is switched from 2Rx to 4 Rx. At time 3, the terminal device receives the PDCCH sent by the network device, and during the period between time 2 and time 3, the terminal device has not reported the CSI to the network device according to the result of measuring the CSI-RS by the changed number of receiving antennas (i.e., 4Rx), at this time, the terminal device and the network device may determine the first CSI, the network device may send the PDSCH scheduled by the PDCCH according to the first CSI reported at time 0, and at the same time, the terminal device may receive the PDSCH scheduled by the PDCCH according to the first CSI reported at time 0.

It is easy to understand that the first CSI reported by the terminal device at time 0 is associated with the first transmission scheme, and data transmission can be performed between the network device and the terminal device through the first transmission scheme, because the accuracy requirement of the first transmission scheme on the CSI is low, the network device can perform rough precoding on the PDSCH according to the limited CSI, and then perform downlink data scheduling between the network device and the terminal device, thereby reducing adverse effects on data transmission caused by mismatch between the used CSI and the actual channel quality, and improving the use experience of the user.

Optionally, if, in the period between time 2 and time 3, the terminal device has reported CSI (whether first CSI or second CSI) to the network device according to the result of measuring the CSI-RS by 4Rx, the PDSCH scheduled by the PDCCH may be transmitted between the network device and the terminal device according to the reported CSI at this time.

In addition, at time 4, the terminal device reports the second CSI to the network device according to the result of measuring the CSI-RS by 4Rx, and after time 4, the PDSCH scheduled by the PDCCH may be transmitted between the network device and the terminal device according to the second CSI reported at time 4.

The communication method according to the embodiment of the present application is described in detail above with reference to fig. 1 to 9, and the apparatus according to the embodiment of the present application is described in detail below with reference to fig. 10 to 13. It will be appreciated that the apparatus shown in figures 10 to 13 is capable of carrying out the steps of one or more of the method flows shown in figures 6, 8. To avoid repetition, detailed description is omitted.

For example, the processing unit 1110 in the communication device 1100 shown in fig. 10 may execute step 220 in fig. 6, and the transceiving unit 1120 may execute

steps

201 and 204, 230 in fig. 6. The processing unit 1310 in the communication device 1300 shown in fig. 12 may execute the step 210 in fig. 6, and the transceiving unit 1320 may execute the

steps

201, 204, 230 in fig. 6.

Fig. 10 is a schematic diagram of a communication apparatus according to an embodiment of the present application, and a communication apparatus 1100 shown in fig. 10 includes: a processing unit 1110 and a transceiver unit 1120. After the number of receiving antennas of the communication apparatus 1100 configured to receive the PDSCH sent by the network device changes, the processing unit 1110 is configured to determine a first CSI according to the changed number of receiving antennas, where the first CSI is a CSI reported by the communication apparatus to the network device according to a result of measuring the CSI-RS by using the changed number of receiving antennas;

the transceiver 1120 is configured to receive the PDSCH transmitted by the network device according to the first CSI.

Optionally, as an embodiment, in a case that the communication apparatus 1100 has not reported the CSI to the network device according to the result of measuring the CSI-RS by using the changed number of receiving antennas, and receives the PDCCH sent by the network device, the processing unit 1110 is further configured to: determining first CSI according to the changed number of the receiving antennas; the transceiver 1120 is further configured to receive the PDSCH scheduled by the PDCCH according to the first CSI.

Optionally, as an embodiment, the changed number of receiving antennas is a first number of receiving antennas, where the processing unit 1110 is further configured to determine the first number of receiving antennas according to the first CSI resource configuration; the transceiver 1120 is further configured to measure a first CSI-RS in a first CSI resource configuration sent by the network device by the first number of receive antennas; and reporting the first CSI to network equipment according to the result of measuring the first CSI-RS.

Alternatively, as one embodiment, the first number of receiving antennas is the maximum number of receiving antennas that can be used by the communication apparatus 1100.

Optionally, as an embodiment, the changed number of receiving antennas is a second number of receiving antennas, where the transceiver 1120 is further configured to measure a second CSI-RS in a second CSI resource configuration sent by the network device by using the second number of receiving antennas, where the second number of receiving antennas is a number of receiving antennas used by the communication apparatus 1100 for receiving the PDSCH sent by the network device when the measurement is performed; and reporting the first CSI to the network equipment according to the result of measuring the second CSI-RS.

Optionally, as an embodiment, the processing unit 1110 is further configured to determine a first resource region, where a resource size of the first resource region is greater than or equal to a resource occupied by a first PUCCH, and the first PUCCH carries CSI obtained by the communication apparatus measuring a second CSI-RS according to a maximum number of receiving antennas that can be used by the communication apparatus 1100; the transceiver unit 1120 is further configured to transmit a second PUCCH on all or part of the first resource region, the second PUCCH carrying the first CSI.

Optionally, as an embodiment, the first CSI includes a first RI value, and a maximum value of the first RI value is determined according to an RI limit value in a CSI report configuration used for reporting the first CSI and a number of receiving antennas used by the communication apparatus 1100 to receive the PDSCH sent by the network device when measuring the CSI-RS corresponding to the first CSI.

Optionally, as an embodiment, the first CSI includes a first RI value, and a maximum value of the first RI value is a smaller value between an RI limit value in a CSI report configuration used for reporting the first CSI and a number of receiving antennas used by the communication apparatus 1100 for receiving the PDSCH transmitted by the network device when measuring the CSI-RS corresponding to the first CSI.

In other embodiments, after the number of receiving antennas used by the communications apparatus 1100 to receive the PDSCH sent by the network device changes, the processing unit 1110 is configured to determine a first CSI, where the first CSI is a CSI reported by the communications apparatus 1100 to the network device according to a first CSI report configuration, and the first CSI report configuration is associated with the first transmission scheme; the transceiver 1120 is configured to receive the PDSCH transmitted by the network device according to the first CSI.

Optionally, as an embodiment, when the communication apparatus 1100 does not report the CSI to the network device according to the result of measuring the CSI-RS by using the changed number of receiving antennas, and receives the PDCCH sent by the network device: processing unit 1110 is further configured to determine the first CSI; the transceiver 1120 is further configured to receive the PDSCH scheduled by the PDCCH according to the first CSI.

Optionally, as an embodiment, before the communication apparatus 1100 determines the first CSI, the transceiver unit 1120 is further configured to report the first CSI to the network device according to a first CSI reporting configuration; the transceiver unit 1120 is further configured to report the second CSI to the network device according to the second CSI reporting configuration, where the second CSI is associated with the second transmission scheme.

Optionally, as an embodiment, the first transmission scheme is a transmit diversity scheme; and/or the second transmission scheme is a non-transmit diversity scheme.

Optionally, as an embodiment, the first transmission scheme is an open loop transmission scheme or a semi-open loop transmission scheme.

Optionally, as an embodiment, the reporting parameter in the first CSI reporting configuration is used to indicate one of the following CSI parameter combinations: cri-RI-i1-CQI, cri-RI-CQI; the reporting parameter in the second CSI reporting configuration is used to indicate one of the following CSI parameter combinations: cri-RI-PMI-CQI, cri-RI-i1, cri-RSRP, ssb-Index-RSRP, cri-RI-LI-PMI-CQI.

In a possible implementation manner, the communication apparatus 1100 may be the terminal device 70, where the functions of the processing unit 1110 may be implemented by the processor 702 in the terminal device, and the functions of the transceiver 1120 may be implemented by the transceiver 701 (i.e., the control circuit and the antenna) of the terminal device. The structure of the terminal device according to the embodiment of the present application is described below with reference to fig. 11.

Fig. 11 is a schematic structural diagram of a terminal device according to an embodiment of the present application. The terminal device can be applied to the system shown in fig. 1, and performs the functions of the terminal device in the above method embodiment. For convenience of explanation, fig. 11 shows only main components of the terminal device. As shown in fig. 11, the terminal device 70 includes a processor, a memory, a control circuit, an antenna, and an input-output means. The processor is mainly configured to process the communication protocol and the communication data, control the entire terminal device, execute a software program, and process data of the software program, for example, to support the terminal device to perform the actions described in the above method embodiments. The memory is used primarily for storing software programs and data. The control circuit is mainly used for converting baseband signals and radio frequency signals and processing the radio frequency signals. The control circuit and the antenna together, which may also be called a transceiver, are mainly used for transceiving radio frequency signals in the form of electromagnetic waves. Input and output devices, such as touch screens, display screens, keyboards, etc., are used primarily for receiving data input by a user and for outputting data to the user.

When the terminal device is turned on, the processor can read the software program in the storage unit, interpret and execute the instruction of the software program, and process the data of the software program. When data needs to be sent wirelessly, the processor outputs a baseband signal to the radio frequency circuit after performing baseband processing on the data to be sent, and the radio frequency circuit performs radio frequency processing on the baseband signal and sends the radio frequency signal outwards in the form of electromagnetic waves through the antenna. When data is sent to the terminal equipment, the radio frequency circuit receives radio frequency signals through the antenna, converts the radio frequency signals into baseband signals and outputs the baseband signals to the processor, and the processor converts the baseband signals into the data and processes the data.

Those skilled in the art will appreciate that fig. 11 shows only one memory and one processor for ease of illustration. In an actual terminal device, there may be multiple processors and multiple memories. The memory may also be referred to as a storage medium or a storage device, and the like, which is not limited in this embodiment of the present application.

As an alternative implementation manner, the processor may include a baseband processor and a central processing unit, where the baseband processor is mainly used to process a communication protocol and communication data, and the central processing unit is mainly used to control the whole terminal device, execute a software program, and process data of the software program. The processor of fig. 11 may integrate the functions of the baseband processor and the central processing unit, and those skilled in the art will understand that the baseband processor and the central processing unit may also be independent processors, and are interconnected through a bus or the like. Those skilled in the art will appreciate that the terminal device may include a plurality of baseband processors to accommodate different network formats, the terminal device may include a plurality of central processors to enhance its processing capability, and various components of the terminal device may be connected by various buses. The baseband processor can also be expressed as a baseband processing circuit or a baseband processing chip. The central processing unit can also be expressed as a central processing circuit or a central processing chip. The function of processing the communication protocol and the communication data may be built in the processor, or may be stored in the storage unit in the form of a software program, and the processor executes the software program to realize the baseband processing function.

Fig. 12 is a schematic diagram of a communication apparatus according to another embodiment of the present application, and a communication apparatus 1300 shown in fig. 12 includes: a processing unit 1310 and a transceiver unit 1320. After the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by communication apparatus 1300 changes:

processing unit 1310 is configured to determine first CSI according to the changed number of receiving antennas, where the first CSI is CSI that terminal equipment reports to communication apparatus 1300 according to a result of measuring CSI-RS by using the changed number of receiving antennas;

the transceiving unit 1320 is configured to transmit the PDSCH to the terminal device according to the first CSI.

Optionally, as an embodiment, in a case that the terminal device has not reported CSI to the communication apparatus 1300 according to a result of measuring the CSI-RS by using the changed number of receiving antennas, and receives a PDCCH sent by the communication apparatus 1300, the processing unit 1310 is further configured to determine the first CSI according to the changed number of receiving antennas; the transceiving unit 1320 is further configured to transmit the PDSCH scheduled by the PDCCH to the terminal device according to the first CSI.

Optionally, as an embodiment, the first CSI includes a first RI value, where the first RI value is determined according to an RI limit value in a CSI report configuration used for reporting the first CSI and a number of receiving antennas used by the terminal device to receive the PDSCH sent by the communication apparatus 1300 when measuring the CSI-RS corresponding to the first CSI.

Optionally, as an embodiment, the first CSI includes a first RI value, and a maximum value of the first RI value is a smaller value between an RI limit value in a CSI report configuration used for reporting the first CSI and a number of receiving antennas used for receiving the PDSCH sent by the communication apparatus 1300 when the terminal device measures the CSI-RS corresponding to the first CSI.

In other embodiments, after the number of receiving antennas used by the terminal device to receive the PDSCH transmitted by the communications apparatus 1300 changes, the processing unit 1310 is configured to determine a first CSI, where the first CSI is a CSI reported by the terminal device to the communications apparatus 1300 according to a first CSI reporting configuration, and the first CSI reporting configuration is associated with the first transmission scheme; the transceiver 1320 is configured to transmit the PDSCH to the terminal device according to the first CSI.

Optionally, as an embodiment, in a case that the terminal device has not reported CSI to the communication apparatus 1300 according to the result of measuring CSI-RS by the changed number of receiving antennas, and receives a PDCCH sent by the communication apparatus 1300, the processing unit 1310 is further configured to determine the first CSI; the transceiving unit 1320 is further configured to transmit the scheduled PDSCH of the PDSCH to the terminal device according to the first CSI.

Optionally, as an embodiment, before the communications apparatus 1300 determines the first CSI, the transceiver 1320 is further configured to receive the first CSI reported by the terminal device according to the first CSI report configuration; the transceiver unit 1320 is further configured to receive second CSI reported by the terminal device according to a second CSI report configuration, where the second CSI is associated with the second transmission scheme.

In one possible implementation, the communication apparatus 1300 may be a network device, such as the base station 80 in the following, wherein the functions of the processing unit 1310 may be implemented by the processor 8022 in the base station, and the functions of the transceiver unit 1320 may be implemented by the RRU 801 of the base station 80. The following describes the structure of a network device according to an embodiment of the present application with reference to fig. 13.

Fig. 13 is a schematic structural diagram of a network device according to an embodiment of the present application, for example, a schematic structural diagram of a base station. As shown in fig. 13, the base station can be applied to the system shown in fig. 1, and performs the functions of the network device in the above method embodiment. The base station 80 may include one or more radio frequency units, such as a Remote Radio Unit (RRU) 801 and one or more baseband units (BBUs) (which may also be referred to as digital units, DUs) 802. The RRU 801 may be referred to as a transceiver unit, transceiver, transceiving circuit, transceiver, or the like, and may include at least one antenna 8011 and a radio frequency unit 8012. The RRU 801 section is mainly used for transceiving radio frequency signals and converting radio frequency signals and baseband signals, for example, for sending signaling messages described in the above embodiments to a terminal device. The BBU 802 part is mainly used for performing baseband processing, controlling a base station, and the like. The RRU 801 and the BBU 802 may be physically disposed together or may be physically disposed separately, that is, distributed base stations.

The BBU 802 is a control center of a base station, and may also be referred to as a processing unit, and is mainly used for performing baseband processing functions, such as channel coding, multiplexing, modulation, and spreading. For example, the BBU (processing unit) 802 may be configured to control the base station to perform the operation procedure related to the network device in the above-described method embodiment.

In an example, the BBU 802 may be formed by one or more boards, and the boards may jointly support a radio access network (e.g., an LTE network) with a single access indication, or may respectively support radio access networks (e.g., LTE networks, 5G networks, or other networks) with different access schemes. The BBU 802 further includes a memory 8021 and a processor 8022, the memory 8021 being configured to store the necessary instructions and data. For example, the memory 8021 stores the correspondence relationship between the codebook index and the precoding matrix in the above-described embodiment. The processor 8022 is configured to control the base station to perform necessary actions, for example, to control the base station to execute the operation flow related to the network device in the above method embodiment. The memory 8021 and processor 8022 may serve one or more boards. That is, the memory and processor may be provided separately on each board. Multiple boards may share the same memory and processor. In addition, each single board can be provided with necessary circuits.

It should be understood that the processor in the embodiments of the present application may be a Central Processing Unit (CPU), and the processor may also be other general purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

It will also be appreciated that the memory in the embodiments of the subject application can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. The non-volatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. Volatile memory can be Random Access Memory (RAM), which acts as external cache memory. By way of example, but not limitation, many forms of Random Access Memory (RAM) are available, such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), Enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct bus RAM (DR RAM).

According to the method provided by the embodiment of the present application, the present application further provides a computer program product, which includes: computer program code which, when run on a computer, causes the computer to perform the method of any of the embodiments shown in figures 6, 8.

According to the method provided by the embodiment of the present application, a computer-readable medium is further provided, and the computer-readable medium stores program codes, and when the program codes are executed on a computer, the computer is caused to execute the method of any one of the embodiments shown in fig. 6 and 8.

According to the method provided by the embodiment of the present application, the present application further provides a system, which includes the foregoing one or more terminal devices and one or more network devices.

The above embodiments may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, the above-described embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product comprises one or more computer instructions or computer programs. The procedures or functions according to the embodiments of the present application are wholly or partially generated when the computer instructions or the computer program are loaded or executed on a computer. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored on a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains one or more collections of available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. The semiconductor medium may be a solid state disk.

In the embodiment of the present application, terms and acronyms such as Channel State Information (CSI), channel state information reference signal (CSI-RS), Physical Downlink Control Channel (PDCCH), Physical Downlink Shared Channel (PDSCH), Radio Resource Control (RRC), and the like are exemplary examples given for convenience of description, and should not limit the present application in any way. This application is not intended to exclude the possibility that other terms may be defined in existing or future protocols to carry out the same or similar functions.

In the embodiments of the present application, the numbers "first", "second", and various numbers are merely used for convenience of description and are not used to limit the scope of the embodiments of the present application. For example, to distinguish between different CSI, different CSI-RS, etc.

The "communication protocol" referred to in the embodiments of the present application may refer to a standard protocol in the field of communication, and may include, for example, an LTE protocol, an NR protocol, and a related protocol applied in a future communication system, which is not limited in the present application.

The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

In the embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of communication, comprising:

after the number of receiving antennas used by a terminal device for receiving a PDSCH sent by a network device changes, the terminal device determines a first CSI according to the changed number of the receiving antennas, wherein the first CSI is a CSI reported to the network device by the terminal device according to a result of measuring a CSI-RS by the changed number of the receiving antennas;

and the terminal equipment receives the PDSCH sent by the network equipment according to the first CSI.

2. The method of claim 1, wherein the terminal device determines the first CSI according to the changed number of receiving antennas, comprising:

when the terminal device does not report CSI to the network device according to the result of measuring the CSI-RS by the changed number of receiving antennas and receives the PDCCH sent by the network device, the terminal device determines first CSI according to the changed number of receiving antennas;

the terminal equipment receives the PDSCH sent by the network equipment according to the first CSI, and the method comprises the following steps:

and the terminal equipment receives the PDSCH scheduled by the PDCCH according to the first CSI.

3. The method according to claim 1 or 2, wherein the changed number of receiving antennas is a first number of receiving antennas, and wherein the communication method further comprises:

the terminal equipment determines the number of the first receiving antennas according to the configuration of the first CSI resources;

the terminal equipment measures a first CSI-RS in the first CSI resource configuration sent by the network equipment according to the first receiving antenna number;

and the terminal equipment reports the first CSI to the network equipment according to the measurement result of the first CSI-RS.

4. The method of claim 3, wherein the first number of receive antennas is a maximum number of receive antennas that can be used by the terminal device.

5. The method according to claim 1 or 2, wherein the changed number of receiving antennas is a second number of receiving antennas, and wherein the communication method further comprises:

the terminal device measures a second CSI-RS in a second CSI resource configuration sent by the network device according to the second receiving antenna number, wherein the second receiving antenna number is the receiving antenna number used by the terminal device for receiving the PDSCH sent by the network device when the measurement is carried out;

and the terminal equipment reports the first CSI to the network equipment according to the result of measuring the second CSI-RS.

6. The method of claim 5, wherein the reporting, by the terminal device, the first CSI to the network device according to the measurement result of the second CSI-RS comprises:

the terminal equipment determines a first resource region, the resource size of the first resource region is larger than or equal to the resource occupied by a first PUCCH, and the first PUCCH carries CSI obtained by the terminal equipment through measuring the second CSI-RS according to the maximum receiving antenna number which can be used by the terminal equipment;

the terminal device sends a second PUCCH on all or part of the first resource region, and the second PUCCH carries the first CSI.

7. The method according to any one of claims 1 to 6, wherein the first CSI includes a first RI value, and a maximum value of the first RI value is determined according to an RI limit value in a CSI report configuration used for reporting the first CSI and a number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device when the terminal device measures the CSI-RS corresponding to the first CSI.

8. The method according to any one of claims 1 to 7, wherein the first CSI comprises a first RI value, and a maximum value of the first RI value is a smaller value of an RI limit value in a CSI reporting configuration used for reporting the first CSI and a number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device when the terminal device measures the CSI-RS corresponding to the first CSI.

9. A method of communication, comprising:

after the number of receiving antennas used by a terminal device for receiving a PDSCH sent by the network device changes, the network device determines a first CSI according to the changed number of the receiving antennas, wherein the first CSI is a CSI reported to the network device by the terminal device according to a result of measuring a CSI-RS by the changed number of the receiving antennas;

and the network equipment sends the PDSCH to the terminal equipment according to the first CSI.

10. The method of claim 9, wherein the network device determines the first CSI according to the changed number of receiving antennas, comprising:

when the terminal device does not report CSI to the network device according to the result of measuring the CSI-RS by the changed number of receiving antennas and receives the PDCCH sent by the network device, the network device determines first CSI according to the changed number of receiving antennas;

the network equipment sends the PDSCH to the terminal equipment according to the first CSI, and the method comprises the following steps:

and the network equipment sends the PDSCH scheduled by the PDCCH to the terminal equipment according to the first CSI.

11. The method according to claim 9 or 10, wherein the first CSI comprises a first RI value, and the first RI value is determined according to an RI limit value in a CSI reporting configuration used for reporting the first CSI and a number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device when the terminal device measures a CSI-RS corresponding to the first CSI.

12. The method according to claim 9 or 10, wherein the first CSI comprises a first RI value, and a maximum value of the first RI value is a smaller value of an RI limit value in a CSI reporting configuration used for reporting the first CSI and a number of receiving antennas used by the terminal device to receive the PDSCH sent by the network device when the terminal device measures the CSI-RS corresponding to the first CSI.

13. A communication apparatus, when a number of receiving antennas used by the communication apparatus to receive a PDSCH transmitted by a network device changes, comprising:

a processing unit, configured to determine first CSI according to the changed number of receiving antennas, where the first CSI is CSI reported to the network device by the communication apparatus according to a result of measuring CSI-RS by using the changed number of receiving antennas;

and the transceiver unit is used for receiving the PDSCH sent by the network equipment according to the first CSI.

14. The apparatus of claim 13, wherein, in a case that the communications apparatus has not reported CSI to the network device according to the measurement result of CSI-RS by the changed number of receiving antennas and receives a PDCCH sent by the network device, the processing unit is further configured to: determining first CSI according to the changed number of the receiving antennas;

the transceiver unit is further configured to: and receiving the PDSCH scheduled by the PDCCH according to the first CSI.

15. The apparatus according to claim 13 or 14, wherein the changed number of receive antennas is a first number of receive antennas, and wherein the processing unit is further configured to: determining the number of first receiving antennas according to a first CSI resource configuration;

the transceiver unit is further configured to: measuring a first CSI-RS in the first CSI resource configuration sent by a network device according to the first receiving antenna number;

and reporting the first CSI to the network equipment according to the measurement result of the first CSI-RS.

16. The apparatus of claim 15, wherein the first number of receive antennas is a maximum number of receive antennas that can be used by the communication apparatus.

17. The apparatus according to claim 13 or 14, wherein the changed number of receiving antennas is a second number of receiving antennas, and wherein the transceiver unit is further configured to:

measuring a second CSI-RS in a second CSI resource configuration sent by the network equipment according to the second receiving antenna number, wherein the second receiving antenna number is the receiving antenna number used by the communication device for receiving the PDSCH sent by the network equipment when the measurement is carried out;

and reporting the first CSI to the network equipment according to the result of measuring the second CSI-RS.

18. The apparatus of claim 17, wherein the processing unit is further configured to:

determining a first resource region, wherein the resource size of the first resource region is larger than or equal to the resource occupied by a first PUCCH, and the first PUCCH carries CSI obtained by the communication device by measuring the second CSI-RS according to the maximum receiving antenna number which can be used by the communication device;

the transceiver unit is further configured to: transmitting a second PUCCH over all or a portion of the first resource region, the second PUCCH carrying the first CSI.

19. The apparatus according to any of claims 13 to 18, wherein the first CSI comprises a first RI value, and a maximum value of the first RI value is determined according to an RI limit value in a CSI reporting configuration used for reporting the first CSI and a number of receiving antennas used by the communication apparatus to receive the PDSCH sent by the network device when measuring the CSI-RS corresponding to the first CSI.

20. The apparatus according to any one of claims 13 to 19, wherein the first CSI comprises a first RI value, and a maximum value of the first RI value is a smaller value of an RI limit value in a CSI reporting configuration used for reporting the first CSI and a number of receiving antennas used by the communication apparatus to receive the PDSCH sent by the network device when the communication apparatus measures the CSI-RS corresponding to the first CSI.

21. A communication apparatus, wherein when a number of receiving antennas used by a terminal device to receive a PDSCH transmitted by the communication apparatus changes, the communication apparatus comprises:

the processing unit is used for determining first CSI according to the changed number of the receiving antennas, wherein the first CSI is the CSI reported to the communication device by the terminal equipment according to the result of measuring the CSI-RS according to the changed number of the receiving antennas;

and the transceiving unit is used for sending the PDSCH to the terminal equipment according to the first CSI.

22. The apparatus of claim 21, wherein, in a case that the terminal device has not reported CSI to the communication apparatus according to the result of measuring CSI-RS by the changed number of receiving antennas and receives the PDCCH sent by the communication apparatus, the processing unit is further configured to: determining first CSI according to the changed number of the receiving antennas; the transceiver unit is further configured to: and sending the PDSCH scheduled by the PDCCH to the terminal equipment according to the first CSI.

23. The apparatus according to claim 21 or 22, wherein the first CSI comprises a first RI value, and the first RI value is determined according to an RI limit value in a CSI reporting configuration used for reporting the first CSI and a number of receiving antennas used by the terminal device to receive the PDSCH sent by the communication apparatus when the terminal device measures the CSI-RS corresponding to the first CSI.

24. The apparatus according to claim 21 or 22, wherein the first CSI comprises a first RI value, and a maximum value of the first RI value is a smaller value of an RI limit value in a CSI reporting configuration used for reporting the first CSI and a number of receiving antennas used by the terminal device to receive the PDSCH sent by the communication apparatus when the terminal device measures the CSI-RS corresponding to the first CSI.

25. A computer-readable storage medium having stored thereon computer instructions for causing a communication device to perform the method of any one of claims 1 to 12.

26. A communications apparatus comprising a processor and a storage medium storing instructions that, when executed by the processor, cause the processor to perform the method of any of claims 1 to 12.