CSI-RS issuing method, network equipment, device and storage medium

Abstract

The invention provides a CSI-RS issuing method, network equipment, a device and a storage medium, and the method comprises the steps: determining the position and moving direction of a terminal based on an AOA value and a TA value reported by the terminal in an MR after the terminal initiates a service in a service cell and requests a CSI-RS; if it is determined that the terminal is located at the edge of the serving cell and moves in the direction away from the serving cell, the moving speed of the terminal is determined based on the AOA value and the TA value reported by the terminal; based on the position, the moving speed and the moving direction of the terminal, predicting an adjacent region into which the terminal will enter and time information when the terminal enters the adjacent region; and sending a CSI-RS issuing request to the neighbor cell, the CSI-RS issuing request carrying the CSI-RS demand information of the terminal and the time information that the terminal predicts to enter the neighbor cell, the CSI-RS issuing request being used for requesting the neighbor cell to prepare for the terminal to issue the CSI-RS in advance, and issuing the CSI-RS to the terminal after the terminal enters the neighbor cell.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technology, and in particular to a CSI-RS sending method, network equipment, apparatus, and storage medium. Background Art

[0002] The Channel State Information-Reference Signal (CSI-RS) in the fifth generation mobile communication (5G) is divided into three forms: periodic, semi-periodic, and dynamic. Periodic CSI-RS fixes the time-frequency resources and period of CSI-RS. The terminal obtains CSI-RS on these fixed resources. Regardless of whether there are terminals in the cell or whether there are terminals that need CSI-RS, the resources are fixedly sent CSI-RS. This form of CSI-RS easily leads to resource waste. Semi-periodic CSI-RS and dynamic CSI-RS, on the other hand, do not continuously send CSI-RS. When a terminal needs CSI-RS, CSI-RS is obtained through random access or reconfiguration. Although these two methods have the effect of saving energy and downlink resources, the terminal's acquisition of CSI-RS increases the signaling burden and also has a certain delay. Summary of the Invention

[0003] In response to the problems existing in the prior art, the present application provides a CSI-RS sending method, network equipment, apparatus and storage medium.

[0004] In a first aspect, the present application provides a CSI-RS delivery method, which is applied to a network device, including:

[0005] When a terminal initiates a service in the serving cell and requests CSI-RS, the terminal's location and moving direction are determined based on the AOA value and TA value reported by the terminal in the MR;

[0006] If it is determined that the terminal is at the edge of the serving cell and is moving away from the serving cell, the moving speed of the terminal is determined based on the AOA value and TA value reported by the terminal;

[0007] Based on the terminal's location, speed, and direction, predict the neighboring cell the terminal will enter and the time the terminal will enter the neighboring cell;

[0008] A CSI-RS delivery request is sent to the neighboring cell. The CSI-RS delivery request carries the terminal's CSI-RS requirement information and the time when the terminal is expected to enter the neighboring cell. The CSI-RS delivery request is used to request the neighboring cell to prepare for CSI-RS delivery for the terminal in advance and deliver CSI-RS to the terminal after the terminal enters the neighboring cell.

[0009] In some embodiments, determining the moving speed of the terminal includes:

[0010] Determine the distance the terminal moves during the time interval between the two moments based on the difference between the AOA values ​​of the terminal at the two moments and the TA values ​​at the two moments;

[0011] The moving speed of the terminal is determined based on the distance the terminal moves within the time interval between two moments and the length of the interval between the two moments.

[0012] In some embodiments, the distance moved by the terminal in the time interval between two moments is determined based on the following formula:

[0013] cosA=(b2+c2-a2) / (2bc)

[0014] Where A represents the difference between the AOA values ​​at two moments, b and c represent the TA distances obtained by converting the TA values ​​at two moments, and a represents the distance the terminal moves during the time interval between the two moments.

[0015] In some embodiments, determining that the terminal is located at an edge of a serving cell includes:

[0016] In the case of gridded serving cells, determining the edge grid of the serving cell;

[0017] If the location coordinates of the terminal are located within the edge grid of the serving cell, it is determined that the terminal is located at the edge of the serving cell.

[0018] In some embodiments, the CSI-RS delivery request also carries the edge grid number of the neighboring cell that the terminal is expected to enter. The edge grid number is used by the neighboring cell to determine the beam resources used to deliver the CSI-RS to the terminal.

[0019] In some embodiments, the method further comprises:

[0020] In the case of multiple terminals, the terminals are clustered based on their locations, moving speeds, and moving directions to obtain multiple terminal clusters.

[0021] For terminals in the same terminal cluster, the neighboring cell that the terminal will enter and the time information of the terminal entering the neighboring cell are uniformly predicted, and a CSI-RS delivery request is uniformly sent to the neighboring cell.

[0022] In a second aspect, the present application also provides a network device, comprising a memory, a transceiver, and a processor;

[0023] a memory for storing a computer program; a transceiver for transceiving data under control of the processor; and a processor for reading the computer program in the memory and performing the following operations:

[0024] determining the position and the moving direction of the terminal based on the AOA value and the TA value reported by the terminal in the MR when the terminal initiates a service in the serving cell and requests the CSI-RS;

[0025] if it is determined that the terminal is located at the edge of the serving cell and moves away from the serving cell, determining the moving speed of the terminal based on the AOA value and the TA value reported by the terminal;

[0026] predicting the neighbor cell into which the terminal will enter and the time information of the terminal entering the neighbor cell based on the position, the moving speed, and the moving direction of the terminal;

[0027] sending a CSI-RS delivery request to the neighbor cell, the CSI-RS delivery request carrying the CSI-RS requirement information of the terminal and the time information of the terminal entering the neighbor cell, the CSI-RS delivery request being used to request the neighbor cell to make preparation for CSI-RS delivery in advance for the terminal and to deliver the CSI-RS to the terminal after the terminal enters the neighbor cell.

[0028] In some embodiments, the moving speed of the terminal is determined by:

[0029] determining the distance moved by the terminal within the time interval between the two time instants based on the difference between the AOA values at the two time instants and the TA values at the two time instants;

[0030] determining the moving speed of the terminal based on the distance moved by the terminal within the time interval between the two time instants and the interval length between the two time instants.

[0031] In some embodiments, the distance moved by the terminal within the time interval between the two time instants is determined based on the following formula:

[0032] cos A = (b2 + c2 - a2) / (2bc)

[0033] wherein A represents the difference between the AOA values at the two time instants, b and c respectively represent the TA distances converted from the TA values at the two time instants, and a represents the distance moved by the terminal within the time interval between the two time instants.

[0034] In some embodiments, the determination that the terminal is located at the edge of the serving cell comprises:

[0035] determining the edge grid of the serving cell in the case of griding the serving cell;

[0036] If the position coordinate of the terminal is located in the edge grid of the serving cell, it is determined that the terminal is located at the edge of the serving cell.

[0037] In some embodiments, the CSI-RS issuing request also carries the edge grid number of the neighboring cell that the terminal is expected to enter, and the edge grid number is used by the neighboring cell to determine the beam resource used for issuing the CSI-RS to the terminal.

[0038] In some embodiments, the operation further includes:

[0039] In the case of multiple terminals, the terminals are clustered based on the positions, moving speeds and moving directions of the terminals, to obtain multiple terminal clusters.

[0040] For the terminals in the same terminal cluster, the neighboring cell that the terminal will enter and the time information of the terminal entering the neighboring cell are uniformly predicted, and the CSI-RS issuing request is uniformly sent to the neighboring cell.

[0041] In a third aspect, the present application also provides a CSI-RS issuing device, which includes:

[0042] The first determining unit is configured to, when a terminal initiates a service in a serving cell and requests a CSI-RS, determine the position and moving direction of the terminal based on the AOA value and TA value reported by the terminal in the MR.

[0043] The second determining unit is configured to, if it is determined that the terminal is located at the edge of the serving cell and is moving away from the serving cell, determine the moving speed of the terminal based on the AOA value and TA value reported by the terminal.

[0044] The predicting unit is configured to predict the neighboring cell that the terminal will enter and the time information of the terminal entering the neighboring cell based on the position, moving speed and moving direction of the terminal.

[0045] The sending unit is configured to send a CSI-RS issuing request to the neighboring cell, the CSI-RS issuing request carrying the CSI-RS demand information of the terminal and the time information of the terminal entering the neighboring cell, the CSI-RS issuing request being used to request the neighboring cell to make preparations for the CSI-RS issuing for the terminal in advance, and to issue the CSI-RS to the terminal after the terminal enters the neighboring cell.

[0046] In some embodiments, the moving speed of the terminal is determined by:

[0047] The distance moved by the terminal within the time interval of the two time instants is determined based on the difference between the AOA values of the terminal at the two time instants and the TA values at the two time instants.

[0048] The moving speed of the terminal is determined based on the distance moved by the terminal within the time interval of the two time instants and the interval length of the two time instants.

[0049] In some embodiments, the distance that the terminal moves in the time interval between the two time instants is determined based on the following formula:

[0050] cos A = (b2 + c2 - a2) / (2bc)

[0051] In the formula, A represents the difference between the AOA values at the two time instants, b and c respectively represent the TA distances converted from the TA values at the two time instants, and a represents the distance that the terminal moves in the time interval between the two time instants.

[0052] In some embodiments, determining that the terminal is located at the edge of the serving cell comprises:

[0053] In the case of meshing the serving cell, determining the edge mesh of the serving cell;

[0054] If the position coordinates of the terminal are located in the edge mesh of the serving cell, it is determined that the terminal is located at the edge of the serving cell.

[0055] In some embodiments, the CSI-RS issuing request also carries the edge mesh number of the neighboring cell that the terminal is expected to enter, and the edge mesh number is used by the neighboring cell to determine the beam resource used for issuing the CSI-RS to the terminal.

[0056] In some embodiments, the apparatus further comprises a clustering unit configured to:

[0057] In the case of multiple terminals, the terminals are clustered based on the positions, moving speeds and moving directions of the terminals, to obtain multiple terminal clusters;

[0058] For the terminals in the same terminal cluster, the neighboring cell that the terminal will enter and the time information of the terminal entering the neighboring cell are uniformly predicted, and the CSI-RS issuing request is uniformly sent to the neighboring cell.

[0059] In a fourth aspect, the present application also provides a non-transitory readable storage medium, which stores a computer program, and the computer program is configured to make a processor execute the CSI-RS issuing method of the first aspect.

[0060] In a fifth aspect, the present application also provides a communication device, which stores a computer program, and the computer program is configured to make the communication device execute the CSI-RS issuing method of the first aspect.

[0061] In a sixth aspect, the present application also provides a processor readable storage medium, which stores a computer program, and the computer program is configured to make a processor execute the CSI-RS issuing method of the first aspect.

[0062] In a seventh aspect, the present application also provides a chip product, wherein a computer program is stored in the chip product, and the computer program is used to make the chip product execute the CSI-RS issuing method in the first aspect.

[0063] The CSI-RS issuing method, the network device, the apparatus and the storage medium provided in the present application can achieve the following effects: when a terminal initiates a service in a serving cell and requests a CSI-RS, the position and the moving direction of the terminal are determined, a predictive CSI-RS issuing scheme is executed for the terminal located at the edge of the serving cell and moving away from the serving cell, the neighbor cell into which the terminal will enter and the time information of the terminal entering the neighbor cell are predicted based on the position, the moving speed and the moving direction of the terminal, and a CSI-RS issuing request is sent to the neighbor cell, wherein the CSI-RS demand information of the terminal and the time information of the terminal entering the neighbor cell are carried in the CSI-RS issuing request, so that the neighbor cell can make preparations for the CSI-RS issuing for the terminal in advance, and the CSI-RS is issued to the terminal as soon as possible after the terminal enters the neighbor cell, thereby achieving the effects of energy saving and downlink resource saving, saving signaling overhead, and reducing the time delay of the terminal acquiring the CSI-RS. BRIEF DESCRIPTION OF DRAWINGS

[0064] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the following will briefly introduce the drawings needed to be used in the embodiment or related art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without any creative effort.

[0065] Figure 1 The flowchart of the CSI-RS issuing method provided in the embodiments of the present application is shown in the figure.

[0066] Figure 2 The terminal moving distance solving schematic diagram provided in the embodiments of the present application is shown in the figure.

[0067] Figure 3 The structure schematic diagram of the network device provided in the embodiments of the present application is shown in the figure.

[0068] Figure 4 The structure schematic diagram of the CSI-RS issuing apparatus provided in the embodiments of the present application is shown in the figure. DETAILED DESCRIPTION

[0069] In the embodiments of the present application, the term "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can mean that there are three cases of A alone, A and B together, and B alone. The character " / " generally represents an "or" relationship between the associated objects before and after it.

[0070] The term "multiple" in the embodiments of the present application refers to two or more, and other quantifiers are similar.

[0071] The terms "first", "second", and the like in the embodiments of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second" are usually of a kind and do not limit the number of objects, for example, the first object can be one or more.

[0072] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0073] In order to more clearly understand the technical solutions of the embodiments of the present application, first, some technical contents related to the embodiments of the present application are introduced.

[0074] In the 5G system, CSI-RS is an important signal for measuring CSI, and the base station configures CSI-RS resources according to the measurement requirements. CSI-RS can be used for Reference Signal Receiving Power (RSRP) measurement, wideband Channel Quality Indicator (CQI) measurement, Precoder Matrix Indicator (PMI) measurement, Tracking function in the New Radio (NR) protocol. Different functions of CSI-RS resources are configured separately. For the Time Division Duplex (TDD) system, due to channel reciprocity, many measurements of the base station can estimate the downlink situation according to the uplink Sounding Reference Signal (SRS), such as the codebook-based beamforming involved in PMI, which can use the SRS measurement result to do non-codebook-based beamforming. Therefore, CSI-RS is not needed in all cases or only part of CSI-RS is needed. For example, when there is no terminal in the cell, it does not make sense to continuously send CSI-RS. Considering the energy saving problem, it is more appropriate not to send CSI-RS at some time.

[0075] In view of this, 5G gives three configuration modes of CSI-RS, the first is periodic CSI-RS, that is, CSI-RS is periodically transmitted, regardless of whether the terminal needs it or whether there is a terminal under the cell, this mode cannot save channel resources and energy. The second is semi-periodic CSI-RS, this CSI-RS is configured by the base station with the time-frequency resources and period of CSI-RS, but it is not issued, when the terminal needs it, it makes a request, and the base station reissues the CSI-RS according to the request and notifies the terminal. The third is dynamic CSI-RS, the base station does not configure the time-frequency resources and period of CSI-RS, when the terminal has a CSI-RS demand, the resource configuration of CSI-RS is temporarily given and the terminal is informed of the configuration of CSI-RS through Radio Resource Control (RRC) reconfiguration. The latter two methods can save channel resources and energy, but when the terminal has a demand for part or all of the CSI-RS function, additional signaling is needed to request the related CSI-RS, which will cause additional signaling burden and time delay in obtaining the CSI-RS in time.

[0076] Figure 1 The flowchart of the CSI-RS delivery method provided by the embodiments of the present application is shown in the figure, and the method is applied to a network device, such as a base station. Figure 1 As shown in the figure, the method comprises the following steps:

[0077] Step 100, after the terminal initiates a service in the serving cell and requests CSI-RS, the position and moving direction of the terminal are determined based on the AOA value and TA value reported by the terminal in the MR.

[0078] Specifically, the present application adopts a pre-judgment type CSI-RS delivery scheme, and the cells in the network can adopt semi-periodic or dynamic CSI-RS configuration. After the terminal initiates a service in the serving cell, it can request to obtain CSI-RS according to the need. Here, the service is not limited to a specific type, such as any service that needs to request to obtain CSI-RS.

[0079] After the terminal requests CSI-RS, the network device (for example: serving base station) can first determine the current position and moving direction of the terminal based on the Angle-of-Arrival (AOA) value and Time Advanced (TA) value reported by the terminal in the Measurement Report (MR).

[0080] Among them, the AOA value can be used to determine which direction the terminal is located at the base station site, and the TA value can be used to determine the distance between the terminal and the base station site, so that the terminal can be accurately positioned. The specific positioning method can refer to the existing technical solutions, which will not be described here.

[0081] Regarding the moving direction of the terminal, one implementation method is: assuming that the latest moving trajectory of the terminal is from position A to position B, the direction pointed by the line connecting position A to position B can be used as the moving direction of the terminal.

[0082] As for the moving direction of the terminal, in step 100, it is also possible to roughly determine whether the terminal is leaving the center of the service cell or moving towards the center of the service cell. For example, if the TA values ​​at two consecutive moments show that the distance between the terminal and the base station site is getting farther and farther, it can be determined that the terminal is moving in the direction of leaving the service cell, otherwise it is moving towards the center of the service cell.

[0083] If it is determined that the terminal is moving toward the center of the serving cell, the subsequent predictive CSI-RS delivery scheme is temporarily not executed for the terminal, and the serving cell delivers the CSI-RS normally according to the needs of the terminal.

[0084] If it is determined that the terminal is not currently at the edge of the serving cell, the subsequent predictive CSI-RS delivery scheme is not executed for the terminal temporarily, and the serving cell delivers the CSI-RS normally according to the needs of the terminal.

[0085] If it is determined that the terminal is currently at the edge of the serving cell and is moving away from the serving cell, a subsequent predictive CSI-RS delivery scheme is executed for the terminal, and subsequent step 101 is executed. It can be understood that when the terminal is still within the service range of the serving cell, the serving cell still delivers the CSI-RS normally according to the needs of the terminal, and simultaneously executes the predictive CSI-RS delivery scheme to prepare for the neighboring cell to deliver the CSI-RS after the terminal enters the neighboring cell.

[0086] Step 101: If it is determined that the terminal is located at the edge of the serving cell and is moving in a direction away from the serving cell, the moving speed of the terminal is determined based on the AOA value and TA value reported by the terminal.

[0087] Specifically, for a terminal located at the edge of a serving cell and moving in a direction away from the serving cell, the network device can further determine the terminal's moving speed for subsequent prediction. The terminal's moving speed can still be calculated using the AOA value and TA value reported by the terminal.

[0088] In some embodiments, determining the moving speed of the terminal includes:

[0089] Determine the distance the terminal moves during the time interval between the two moments based on the difference between the AOA values ​​of the terminal at the two moments and the TA values ​​at the two moments;

[0090] The moving speed of the terminal is determined based on a distance moved by the terminal in a time interval between two time instants and a time interval between the two time instants.

[0091] The two time instants are not limited in the present application as long as they can be used to determine the moving speed of the terminal. In some embodiments, the two time instants can be selected according to a preset rule, which can be flexibly set according to the accuracy requirement of the moving speed. For example, one of the two time instants (referred to as time instant 1) can be the most recent measurement time instant, and the other (referred to as time instant 2) can be the second most recent measurement time instant or a measurement time instant that is a preset time interval away from time instant 1. The preset time interval can be one unit of time, such as 1 second, 5 seconds, etc.

[0092] Based on the difference between the AOA values of the terminal at the two time instants and the TA values at the two time instants, the distance moved by the terminal in the time interval between the two time instants can be calculated, and then the distance is divided by the time interval between the two time instants to calculate the moving speed of the terminal.

[0093] In some embodiments, the distance moved by the terminal in the time interval between the two time instants can be determined based on the following formula:

[0094] cos A = (b2 + c2 - a2) / (2bc)

[0095] In the formula, A represents the difference between the AOA values of the two time instants, b and c respectively represent the TA distances converted from the TA values at the two time instants, and a represents the distance moved by the terminal in the time interval between the two time instants.

[0096] Referring to Figure 2 the terminal moving distance solving schematic diagram, TA1 is the TA distance converted from the TA value at time instant 1, TA2 is the TA distance converted from the TA value at time instant 2, AOA1 is the AOA value at time instant 1, AOA2 is the AOA value at time instant 2, and angle A (∠A) is the difference between the AOA values at time instant 1 and time instant 2. In the case where b = TA1, c = TA2, and ∠A = AOA1 - AOA2, a, i.e., the distance moved by the terminal in the time interval between the two time instants, can be calculated according to the above formula.

[0097] The TA distance converted from the TA value refers to the distance value obtained by multiplying the TA value (the unit of TA is time) by a unit TA distance (such as 200 meters / second, 300 meters / second, etc.). For details, refer to the prior art, which will not be described here.

[0098] In some embodiments, if the moving direction of the terminal is only roughly determined in step 100, a more accurate determination of the moving direction of the terminal is needed before the subsequent prediction, which can be achieved by the method as described above. In one embodiment, assuming that the latest moving track of the terminal is from position A to position B, the direction of the line connecting position A and position B can be taken as the moving direction of the terminal. In another embodiment, the difference between the AOA values at two time instants and the TA values at the two time instants can be used to calculate the direction of the line connecting the terminal positions at the two time instants, as shown in FIG. 8. Figure 2 With the determination of b, c and ∠A, the direction of the line connecting the terminal positions at the two time instants can be calculated by using the geometric relationship.

[0099] In step 102, the neighbor cells that the terminal will enter and the time information of the terminal entering the neighbor cells are predicted based on the position, moving speed and moving direction of the terminal.

[0100] Specifically, after the position, moving speed and moving direction of the terminal are determined, the neighbor cells that the terminal will enter can be predicted. In the case where the position, moving speed and moving direction of the terminal are known, the neighbor cells that the terminal will enter and the time information of the terminal entering the neighbor cells can be predicted in multiple specific implementation manners, which can also refer to the related art. The present application does not limit the specific implementation manner.

[0101] In some embodiments, in the case where the azimuth and coverage area of the neighbor cells around the current serving cell are known, after the position, moving speed and moving direction of the terminal are determined, a sector area starting from the current position of the terminal and extending along the moving direction of the terminal can be determined to be located in the coverage area of which neighbor cells, and these neighbor cells can be the predicted neighbor cells that the terminal will enter. The angle and radius of the sector area can be a pre-set value (for example, a fixed angle value and radius value are pre-set, and the fixed angle value and radius value are used to determine the sector area for all terminals) or be associated with the moving speed of the terminal (for example, multiple different speed intervals are set, each speed interval corresponds to a set of angle value and radius value, and the moving speed of the terminal falls in which speed interval, the corresponding set of angle value and radius value is used to determine the sector area). Correspondingly, the time information (time point or time range) of the terminal entering these neighbor cells can be predicted according to the current position of the terminal, the coverage area of each neighbor cell in the sector area and the moving speed of the terminal.

[0102] In step 103, a CSI-RS issuing request is sent to the neighbor cell, which carries the CSI-RS requirement information of the terminal and the time information of the terminal entering the neighbor cell. The CSI-RS issuing request is used to request the neighbor cell to make preparation for the CSI-RS issuing in advance for the terminal, and to issue the CSI-RS to the terminal after the terminal enters the neighbor cell.

[0103] In particular, after predicting the neighbor cell that the terminal will enter and the time information of the terminal entering the neighbor cell, the network device can send a CSI-RS delivery request to each neighbor cell that the terminal can enter, and the CSI-RS delivery request carries the CSI-RS requirement information of the terminal and the time information of the terminal entering the neighbor cell.

[0104] In some embodiments, the CSI-RS requirement information can be indication information indicating whether the terminal needs to be delivered with CSI-RS.

[0105] In some embodiments, the CSI-RS delivery request can be sent through the Xn interface between base stations.

[0106] The neighbor cell receiving the CSI-RS delivery request can make preparations for CSI-RS delivery in advance for the terminal according to the CSI-RS requirement information of the terminal and the time information of the terminal entering the neighbor cell, such as preparing downlink resources and CSI-RS to be delivered to the terminal in advance. If the terminal subsequently enters the neighbor cell, the neighbor cell can deliver CSI-RS to the terminal in the first time after a successful handover without the terminal initiating a CSI-RS request, thereby saving signaling overhead and reducing the latency of the terminal obtaining CSI-RS.

[0107] In some embodiments, when a new round of prediction is performed, if it is found that a certain (or certain) neighbor cell is no longer a neighbor cell that the terminal can enter, the network device can notify the neighbor cell to cancel the CSI-RS delivery preparation made in advance for the terminal to release resources.

[0108] In some embodiments, after receiving the CSI-RS delivery request, the neighbor cell can start a CSI-RS delivery timer, maintain the CSI-RS delivery preparation made in advance for the terminal before the terminal enters the neighbor cell, or deliver CSI-RS in a semi-periodic or dynamic manner after the terminal enters the neighbor cell, cancel the CSI-RS delivery preparation made in advance for the terminal to release resources after the timer expires, and deliver CSI-RS to the terminal in a regular manner (i.e., periodically or according to the terminal request).

[0109] The CSI-RS issuing method provided by the embodiments of the present application comprises the following steps: when a terminal initiates a service in a serving cell and requests a CSI-RS, the position and moving direction of the terminal are determined; a predictive CSI-RS issuing scheme is performed for the terminal located at the edge of the serving cell and moving away from the serving cell; based on the position, moving speed and moving direction of the terminal, the neighboring cell into which the terminal will enter and the time information of the terminal entering the neighboring cell are predicted, and a CSI-RS issuing request is sent to the neighboring cell, wherein the CSI-RS demand information of the terminal and the time information of the terminal entering the neighboring cell are carried in the CSI-RS issuing request, so that the neighboring cell can make preparations for the CSI-RS issuing in advance for the terminal, and the CSI-RS is issued to the terminal as soon as possible after the terminal enters the neighboring cell, thereby achieving the effects of energy saving and downlink resource saving, saving signaling overhead, and reducing the time delay of the terminal acquiring the CSI-RS.

[0110] In some embodiments, the determination that the terminal is located at the edge of the serving cell comprises:

[0111] In the case of the gridization of the serving cell, the edge grid of the serving cell is determined;

[0112] If the position coordinates of the terminal are located in the edge grid of the serving cell, it is determined that the terminal is located at the edge of the serving cell.

[0113] Specifically, in order to facilitate the determination of whether the terminal is located at the edge of the serving cell, the cell can be gridized, and the edge grid and the non-edge grid are divided for the coverage range of each cell. When determining whether the terminal is located at the edge of the serving cell, the edge grid of the serving cell is first determined, and then if the position coordinates of the terminal are located in the edge grid of the serving cell, it is determined that the terminal is located at the edge of the serving cell.

[0114] In some embodiments, the cell can be gridized by the downlink time difference of arrival (DL-TDOA) technology. Assuming that the outdoor measurement accuracy of the DL-TDOA is within 5m, the coverage range of each cell can be divided into a plurality of small grids with an accuracy of 5m, and numbered. The grid where the switching band between different cells is located and the grid adjacent to the switching band are divided into edge grids, and the other grids are divided into non-edge grids. The grid numbers of the switching bands of adjacent cells are consistent, and the edge grid numbers are bound through the adjacency relationship.

[0115] The switching band mentioned above refers to some overlapping area existing in the coverage ranges of two different cells. In this area, the terminal can effectively and reliably perform cell switching to ensure the continuity of communication.

[0116] In some embodiments, the CSI-RS issuing request further carries the edge grid number of the neighboring cell that the terminal is expected to enter, and the edge grid number is used by the neighboring cell to determine the beam resource used for issuing the CSI-RS to the terminal.

[0117] Specifically, in the case of cell grid, the grid number covered by each beam can also be determined for the Synchronization Signal and PBCH Block (SSB) beam. When predicting the neighboring cell that the terminal will enter, the edge grid number of the neighboring cell that the terminal is expected to enter can be further determined, that is, which edge grids the terminal is likely to enter the neighboring cell. The edge grid number of the neighboring cell that the terminal is expected to enter is carried in the CSI-RS issuing request and sent to the corresponding neighboring cell.

[0118] Since the grid number has a corresponding relationship with the beam, the neighboring cell receiving the CSI-RS issuing request can determine the beam resource used for issuing the CSI-RS to the terminal according to the edge grid number of the neighboring cell that the terminal is expected to enter and the beams corresponding to the edge grid numbers. For example, assuming that the edge grid number of the neighboring cell that the terminal is expected to enter carried in the CSI-RS issuing request is 1#, and in the coverage beam of the neighboring cell, beam 1 covers the 1# grid, then the neighboring cell can determine to use beam 1 (or beam 1 and the beams adjacent to beam 1) for subsequent CSI-RS issuing to the terminal, so as to more accurately prepare for CSI-RS issuing and avoid waste of resources.

[0119] In some embodiments, the method further comprises:

[0120] In the case of multiple terminals, the terminals are clustered based on the positions, moving speeds and moving directions of the terminals, to obtain multiple terminal clusters;

[0121] For the terminals in the same terminal cluster, the neighboring cell that the terminal will enter and the time information of the terminal entering the neighboring cell are uniformly predicted, and a CSI-RS issuing request is uniformly sent to the neighboring cell.

[0122] Specifically, in order to improve the execution efficiency of the predictive CSI-RS issuing scheme and save the computing resources of the network device, multiple terminals located at the edge of the serving cell and moving away from the serving cell can be clustered. The input features for clustering include the positions, moving speeds and moving directions of the terminals. After clustering, multiple terminal clusters can be obtained. The terminals in the same terminal cluster can be considered to have similar motion rules (such as being located on the same vehicle), and the neighboring cell that the terminal will enter and the time information of the terminal entering the neighboring cell can be uniformly predicted as a whole, and a CSI-RS issuing request can be uniformly sent to the neighboring cell. The specific clustering method is not limited in the present application, and can refer to the existing technical solutions, which will not be described here.

[0123] For the terminals in the same terminal cluster, how to uniformly predict the neighbor cell that the terminal will enter and the time information of the terminal entering the neighbor cell can have various specific implementation schemes, and can also refer to the existing related technologies, and the present application does not make any limitation. In some embodiments, all the terminals in the same terminal cluster can be equivalent to a nominal terminal (referred to as a nominal terminal), the data of the cluster center of the terminal cluster in three feature dimensions (position, moving speed and moving direction) can be taken as the position, moving speed and moving direction of the nominal terminal, then the method described in the foregoing can be used to predict the neighbor cell that the nominal terminal will enter and the time information of the nominal terminal entering the neighbor cell, and a CSI-RS issuing request is sent to the corresponding neighbor cell, carrying the CSI-RS demand information of each terminal in the terminal cluster and the time information of the nominal terminal entering the neighbor cell.

[0124] The CSI-RS issuing scheme provided by the present application is exemplified by a specific application scenario as follows, and the main process of the example includes:

[0125] 1. The terminal initiates a service in a serving cell and requests to obtain a CSI-RS as needed.

[0126] 2. The base station determines the moving track (including position, moving direction, etc.) of the terminal according to the AOA value and the TA value reported in the MR.

[0127] 3. The cells are gridded by DL-TDOA technology, and the grid number of each SSB beam coverage is determined.

[0128] 1) The outdoor measurement accuracy of DL-TDOA is within 5m, and the coverage range of each cell is divided into several small grids with an accuracy of 5m, and the grid numbers are given. The grid of the handover zone with other cells and the grid adjacent to the handover zone are edge grids, and other grids are non-edge grids. The grid numbers of the handover zone of adjacent cells are consistent, and the edge grid numbers are bound through adjacency relationship.

[0129] 2) The correspondence between the SSB beam and the grid number is determined, and the grid covered by each beam is determined.

[0130] 4. When the terminal is in an edge grid and the moving track is in the direction away from the serving cell, the moving speed and the moving direction of the terminal are determined by the base station of the serving cell according to the AOA difference value of the two time points and the TA value of the two time points. The two time points can be one unit time apart.

[0131] 5. Clustering is performed by using the k-means algorithm, and the input features include the location, moving speed and moving direction of the terminal. A plurality of terminal clusters are obtained by clustering, and the terminals in the same terminal cluster can be considered as similar in moving law (for example, located on the same vehicle) and can be regarded as a whole.

[0132] 6. According to the location, moving speed and moving direction of the terminal similar in moving law and the edge grids of other cells adjacent to the edge grid where the terminal is located, a plurality of neighboring cells that the terminal is likely to enter and time information of entering the neighboring cells are predicted.

[0133] 7. The CSI-RS requirement of the terminal similar in moving law and the time information of entering the neighboring cells are notified to the corresponding neighboring cells in advance through the Xn interface.

[0134] 8. After receiving the handover request from the source cell, the neighboring cell performs admission control, and when the admission control is passed, the handover request ACK (acknowledgement) is sent, and the CSI-RS required by the terminal is prepared to be sent. When the terminal is allocated with the PDSCH (Physical Downlink Shared Channel) resource, the corresponding CSI-RS signal is sent.

[0135] The method and device provided by the embodiments of the present application are based on the same application concept. Since the principles of the method and device for solving problems are similar, the implementation of the device and the method can be referred to each other, and the repeated parts will not be described again.

[0136] Figure 3 The structural schematic diagram of the network device provided by the embodiments of the present application is shown as in Figure 3 The network device includes a memory 320, a transceiver 310 and a processor 300. The processor 300 and the memory 320 can also be arranged physically separately.

[0137] The memory 320 is used to store a computer program, and the transceiver 310 is used to transceive data under the control of the processor 300.

[0138] Specifically, the transceiver 310 is used to receive and send data under the control of the processor 300.

[0139] Wherein, under the control of the processor 300, the transceiver 310 is used to receive and send data. Figure 3In particular embodiments, the bus architecture can include any number of interconnecting buses and bridges, depending on the specific application of the processor 300 and the architecture of the memory 320 that is represented by various circuitry linking the processor 300 and the memory 320. The bus architecture can also link various other circuits such as peripheral devices, voltage regulators, and power management circuitry, all of which are well known in the art, and therefore, will not be described further. A bus interface provides the interface. The transceiver 310 can be a plurality of elements, including a transmitter and a receiver, that provides the means for communicating with various other apparatus over a transmission medium, including a wireless channel, a wired channel, optical cable, and the like.

[0140] The processor 300 is responsible for managing the bus architecture and general processing, and the memory 320 can store data used by the processor 300 in executing operations.

[0141] The processor 300 can be a Central Processing Unit (CPU), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or a Complex Programmable Logic Device (CPLD), and the processor can also adopt a multi-core architecture.

[0142] The processor 300, by invoking the computer program stored in the memory 320, is configured to execute any of the methods provided by the embodiments of the present application according to the obtained executable instructions, for example: determining the position and the moving direction of the terminal based on the AOA value and the TA value reported by the terminal in the MR when the terminal initiates a service in the serving cell and requests the CSI-RS; if it is determined that the terminal is located at the edge of the serving cell and moves away from the serving cell, determining the moving speed of the terminal based on the AOA value and the TA value reported by the terminal; predicting the neighbor cell that the terminal will enter and the time information of the terminal entering the neighbor cell based on the position, the moving speed, and the moving direction of the terminal; sending a CSI-RS delivery request to the neighbor cell, the CSI-RS delivery request carrying the CSI-RS requirement information of the terminal and the time information of the terminal entering the neighbor cell, the CSI-RS delivery request being used to request the neighbor cell to make preparation for CSI-RS delivery in advance for the terminal, and delivering the CSI-RS to the terminal after the terminal enters the neighbor cell.

[0143] In some embodiments, the determining the moving speed of the terminal comprises:

[0144] determine the distance that the terminal moves in the time interval between the two time instants based on the difference between the AOA values of the terminal at the two time instants and the TA values of the terminal at the two time instants;

[0145] determine the moving speed of the terminal based on the distance that the terminal moves in the time interval between the two time instants and the interval length between the two time instants.

[0146] In some embodiments, the distance that the terminal moves in the time interval between the two time instants is determined based on the following formula:

[0147] cos A = (b2 + c2 - a2) / (2bc)

[0148] In the formula, A represents the difference between the AOA values of the terminal at the two time instants, b and c respectively represent the TA distances converted from the TA values of the terminal at the two time instants, and a represents the distance that the terminal moves in the time interval between the two time instants.

[0149] In some embodiments, determining that the terminal is located at the edge of the serving cell comprises:

[0150] In the case of meshing the serving cell, determining the edge mesh of the serving cell;

[0151] If the position coordinates of the terminal are located in the edge mesh of the serving cell, it is determined that the terminal is located at the edge of the serving cell.

[0152] In some embodiments, the CSI-RS issuing request also carries the edge mesh number of the neighboring cell that the terminal is expected to enter, and the edge mesh number is used by the neighboring cell to determine the beam resource used for issuing the CSI-RS to the terminal.

[0153] In some embodiments, the method further comprises:

[0154] In the case of multiple terminals, clustering the terminals based on the positions, moving speeds and moving directions of the terminals to obtain multiple terminal clusters;

[0155] For the terminals in the same terminal cluster, the neighboring cell that the terminal will enter and the time information of the terminal entering the neighboring cell are uniformly predicted, and the CSI-RS issuing request is uniformly sent to the neighboring cell.

[0156] It should be noted that the above network device provided by the embodiments of the present application can realize all the method steps realized by the above method embodiments, and can achieve the same technical effects. Therefore, the same parts and beneficial effects of the method embodiments will not be described in detail here.

[0157] Figure 4 The structure diagram of the CSI-RS issuing device provided by the embodiments of the present application is shown in FIG. 1, which comprises: Figure 4 ​

[0158] The first determining unit 400 is configured to determine the position and the moving direction of the terminal based on the AOA value and the TA value reported by the terminal in the MR when the terminal initiates a service in the serving cell and requests the CSI-RS.

[0159] The second determining unit 410 is configured to determine the moving speed of the terminal based on the AOA value and the TA value reported by the terminal if it is determined that the terminal is located at the edge of the serving cell and moves away from the serving cell.

[0160] The predicting unit 420 is configured to predict the neighbor cell into which the terminal will enter and the time information of the terminal entering the neighbor cell based on the position, the moving speed and the moving direction of the terminal.

[0161] The sending unit 430 is configured to send a CSI-RS delivery request to the neighbor cell, the CSI-RS delivery request carrying the CSI-RS requirement information of the terminal and the time information of the terminal entering the neighbor cell, the CSI-RS delivery request being used to request the neighbor cell to make preparation for CSI-RS delivery in advance for the terminal and to deliver the CSI-RS to the terminal after the terminal enters the neighbor cell.

[0162] In some embodiments, the moving speed of the terminal is determined by:

[0163] determining the distance moved by the terminal within the time interval between the two time instants based on the difference between the AOA values at the two time instants and the TA values at the two time instants; and

[0164] determining the moving speed of the terminal based on the distance moved by the terminal within the time interval between the two time instants and the interval length between the two time instants.

[0165] In some embodiments, the distance moved by the terminal within the time interval between the two time instants is determined based on the following formula:

[0166] cos A = (b2 + c2 - a2) / (2bc)

[0167] In the formula, A represents the difference between the AOA values at the two time instants, b and c respectively represent the TA distances converted from the TA values at the two time instants, and a represents the distance moved by the terminal within the time interval between the two time instants.

[0168] In some embodiments, the determination that the terminal is located at the edge of the serving cell comprises:

[0169] determining the edge grid of the serving cell in the case of griding the serving cell;

[0170] if the position coordinates of the terminal are located in the edge grid of the serving cell, determining that the terminal is located at the edge of the serving cell.

[0171] In some embodiments, the CSI-RS issuing request also carries an edge grid number of a neighbor cell that the terminal is expected to enter, and the edge grid number is used for the neighbor cell to determine a beam resource used for issuing the CSI-RS to the terminal.

[0172] In some embodiments, the apparatus further includes a clustering unit configured to:

[0173] In the case of multiple terminals, the terminals are clustered based on the positions, moving speeds and moving directions of the terminals, to obtain multiple terminal clusters.

[0174] For the terminals in the same terminal cluster, the neighbor cell that the terminal is expected to enter and the time information of the terminal entering the neighbor cell are uniformly predicted, and a CSI-RS issuing request is uniformly sent to the neighbor cell.

[0175] It should be noted that the division of the units in the embodiments of the present application is illustrative, and is merely a logical function division. In actual implementation, another division manner can be used. In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0176] When the integrated unit is realized in the form of a software functional unit and sold or used as an independent product, it can be stored in a processor-readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to perform all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0177] It should be noted that the above apparatus provided by the embodiments of the present application can realize all the method steps realized by the above method embodiments, and can achieve the same technical effects. Therefore, the same parts and beneficial effects of the method embodiments in the embodiments of the present application will not be described in detail.

[0178] In another aspect, the embodiments of the present application also provide a non-transitory readable storage medium, which stores a computer program, and the computer program is used to make a processor execute the CSI-RS delivery method provided by the above-mentioned embodiments.

[0179] It should be noted that the non-transitory readable storage medium provided by the embodiments of the present application can realize all the method steps achieved by the above-mentioned method embodiments, and achieve the same technical effects. Therefore, the same parts and beneficial effects of the embodiments of the present application as the method embodiments will not be described in detail.

[0180] The non-transitory readable storage medium can be any available medium or data storage device that can be accessed by a computer, including but not limited to a magnetic storage (such as a floppy disk, a hard disk, a magnetic tape, a magneto-optical disk (MO), etc.), an optical storage (such as a CD, a DVD, a BD, a HVD, etc.), and a semiconductor storage (such as a ROM, an EPROM, an EEPROM, a non-volatile memory (NAND FLASH), a solid state disk (SSD)), etc.

[0181] The technical solutions provided by the embodiments of the present application can be applied to various systems, especially 5G systems. For example, the applicable systems can be global system of mobile communication (GSM) systems, code division multiple access (CDMA) systems, wideband code division multiple access (WCDMA) general packet radio service (GPRS) systems, long term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, LTE time division duplex (TDD) systems, long term evolution advanced (LTE-A) systems, universal mobile system (UMTS), worldwide interoperability for microwave access (WiMAX) systems, 5G new radio (NR) systems, and the like. Among these various systems, there are terminal devices and network devices. The system can also include a core network part, such as an evolved packet system (EPS), a 5G system (5GS), and the like.

[0182] The terminal referred to in the embodiments of the present application can refer to a device that provides voice and / or data connectivity to a user, a handheld device having wireless connection function, or other processing devices connected to a wireless modem, etc. In different systems, the name of the terminal can also be different, for example, in the 5G system, the terminal can be called a user equipment (UE). The wireless terminal device can communicate with one or more core networks (CN) through a radio access network (RAN). The wireless terminal device can be a mobile terminal device, such as a mobile phone (or called a "cellular" phone) and a computer with a mobile terminal device, for example, it can be a portable, pocket, handheld, computer built-in or vehicle-mounted mobile device, which exchanges language and / or data with the radio access network. For example, personal communication service (PCS) phones, cordless phones, session initiated protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), etc. The wireless terminal device can also be called a system, a subscriber unit, a subscriber station, a mobile station, a mobile, a remote station, an access point, a remote terminal, an access terminal, a user terminal, a user agent, a user device, which is not limited in the embodiments of the present application.

[0183] The network device involved in the embodiments of the present application can be a base station, which can include multiple cells serving terminals. According to different application scenarios, the base station can also be referred to as an access point, or can be a device in an access network that communicates with wireless terminal devices through one or more sectors over an air interface, or other names. The network device can be used to exchange received air frames and Internet Protocol (IP) packets as a router between wireless terminal devices and the rest of the access network, which can include an Internet Protocol (IP) communication network. The network device can also coordinate the management of the properties of the air interface. For example, the network device involved in the embodiments of the present application can be a network device (Base Transceiver Station, BTS) in the Global System for Mobile Communications (GSM) or Code Division Multiple Access (CDMA), or a network device (NodeB) in Wide-band Code Division Multiple Access (WCDMA), or an evolved network device (evolutional Node B, eNB or e-NodeB) in a long term evolution (LTE) system, or a 5G base station (gNB) in a next generation system, or a Home evolved Node B (HeNB), a relay node, a femto, a pico, etc., which are not limited in the embodiments of the present application. In some network structures, the network device can include a centralized unit (CU) node and a distributed unit (DU) node, and the centralized unit and the distributed unit can also be arranged geographically apart.

[0184] The network device and the terminal can each use one or more antennas for Multi Input Multi Output (MIMO) transmission, which can be Single User MIMO (SU-MIMO) or Multiple User MIMO (MU-MIMO). According to the shape and number of antenna combinations, MIMO transmission can be 2D-MIMO, 3D-MIMO, FD-MIMO or massive-MIMO, or can be diversity transmission or precoding transmission or beamforming transmission, etc.

[0185] Those skilled in the art will appreciate that embodiments of the application can be readily used as software, hardware, or a combination of software and hardware. In one

[0186] The processes and logic flows described in this specification can be performed by one or more programmable computers executing one or more computer programs to Figure 1 The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic Figure 1 The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic

[0187] These processor-executable instructions can also be stored in a processor-readable memory that can direct a computer or other programmable data processing apparatus to Figure 1 The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic Figure 1 The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic

[0188] These processor-executable instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operations to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the Figure 1 The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic Figure 1 The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic

[0189] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their legal equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A method for downlinking a channel state information reference signal (CSI-RS), characterized in that, The application is applied to a network device, comprising: When a terminal initiates a service in a serving cell and requests a CSI-RS, based on an angle of arrival (AOA) value and a time advance (TA) value reported by the terminal in a measurement report (MR), the position and moving direction of the terminal are determined; If it is determined that the terminal is located at the edge of the serving cell and moves away from the serving cell, based on the AOA value and the TA value reported by the terminal, the moving speed of the terminal is determined; Based on the position, moving speed and moving direction of the terminal, a neighbor cell into which the terminal will enter and time information of the terminal entering the neighbor cell are predicted; A CSI-RS issuing request is sent to the neighbor cell, the CSI-RS issuing request carrying CSI-RS requirement information of the terminal and time information of the terminal entering the neighbor cell, the CSI-RS issuing request being used to request the neighbor cell to make preparation for CSI-RS issuing in advance for the terminal and to issue the CSI-RS to the terminal after the terminal enters the neighbor cell.

2. The CSI-RS issuing method of claim 1, wherein, The determination of the moving speed of the terminal comprises: Based on the difference between the AOA values at two time instants and the TA values at the two time instants, the distance moved by the terminal within the time interval between the two time instants is determined; Based on the distance moved by the terminal within the time interval between the two time instants and the interval length between the two time instants, the moving speed of the terminal is determined.

3. The CSI-RS issuing method of claim 2, wherein, The distance moved by the terminal within the time interval between the two time instants is determined based on the following formula: cos A = (b2 + c2 - a2) / (2bc) In the formula, A represents the difference between the AOA values at the two time instants, b and c respectively represent TA distances converted from the TA values at the two time instants, and a represents the distance moved by the terminal within the time interval between the two time instants.

4. The CSI-RS issuing method of claim 1, wherein, The determination that the terminal is located at the edge of the serving cell comprises: In the case of griding the serving cell, the edge grid of the serving cell is determined; If the position coordinates of the terminal are located within the edge grid of the serving cell, it is determined that the terminal is located at the edge of the serving cell.

5. The CSI-RS issuing method of claim 1 or 4, wherein, The CSI-RS issuing request further carries an edge grid number of the neighbor cell into which the terminal is expected to enter, the edge grid number being used by the neighbor cell to determine beam resources used for issuing the CSI-RS to the terminal.

6. The CSI-RS issuing method of claim 1, wherein, The method further comprises: In the case of multiple terminals, based on the position, moving speed and moving direction of the terminals, the terminals are clustered to obtain multiple terminal clusters; For the terminals in the same terminal cluster, the neighbor cell into which the terminal will enter and the time information of the terminal entering the neighbor cell are uniformly predicted, and the CSI-RS issuing request is uniformly sent to the neighbor cell.

7. A network device, comprising: The application comprises a memory, a transceiver and a processor; The memory is used to store a computer program; the transceiver is used to transceive data under the control of the processor; and the processor is used to read the computer program in the memory and perform the following operations: When a terminal initiates a service in a serving cell and requests a channel state information reference signal (CSI-RS), a position and a moving direction of the terminal are determined based on angle of arrival (AOA) values and time advance (TA) values reported by the terminal in a measurement report (MR); If it is determined that the terminal is located at an edge of the serving cell and moves away from the serving cell, a moving speed of the terminal is determined based on the AOA values and the TA values reported by the terminal; Based on the position, the moving speed and the moving direction of the terminal, a neighbor cell into which the terminal will enter and time information of the terminal entering the neighbor cell are predicted; A CSI-RS delivery request is sent to the neighbor cell, the CSI-RS delivery request carrying CSI-RS requirement information of the terminal and the time information of the terminal entering the neighbor cell, the CSI-RS delivery request being used to request the neighbor cell to make preparation for CSI-RS delivery in advance for the terminal and to deliver the CSI-RS to the terminal after the terminal enters the neighbor cell.

8. The network device of claim 7, wherein, The determination of the moving speed of the terminal comprises: a distance moved by the terminal within a time interval between two time instants is determined based on a difference between AOA values at the two time instants and TA values at the two time instants; a moving speed of the terminal is determined based on the distance moved by the terminal within the time interval between the two time instants and a time length of the interval between the two time instants.

9. The network device of claim 8, wherein, The distance moved by the terminal within the time interval between the two time instants is determined based on the following formula: cos A = (b2 + c2 - a2) / (2bc) In the formula, A represents the difference between the AOA values at the two time instants, b and c respectively represent TA distances converted from the TA values at the two time instants, and a represents the distance moved by the terminal within the time interval between the two time instants.

10. The network device of claim 7, wherein, The determination that the terminal is located at the edge of the serving cell comprises: in a case where the serving cell is gridized, an edge grid of the serving cell is determined; if a position coordinate of the terminal is located in the edge grid of the serving cell, it is determined that the terminal is located at the edge of the serving cell.

11. The network device of claim 7 or 10, wherein, The CSI-RS delivery request further carries an edge grid number of the neighbor cell into which the terminal is expected to enter, the edge grid number being used by the neighbor cell to determine beam resources used for delivering the CSI-RS to the terminal.

12. The network device of claim 7, wherein, The operations further comprise: in a case where there are a plurality of terminals, the terminals are clustered based on the positions, the moving speeds and the moving directions of the terminals, to obtain a plurality of terminal clusters; for terminals in a same terminal cluster, neighbor cells into which the terminals will enter and time information of the terminals entering the neighbor cells are uniformly predicted, and the CSI-RS delivery request is uniformly sent to the neighbor cell.

13. A channel state information reference signal (CSI-RS) downlink apparatus, comprising: comprise: a first determination unit configured to, when a terminal initiates a service in a serving cell and requests a CSI-RS, determine a position and a moving direction of the terminal based on angle of arrival (AOA) values and time advance (TA) values reported by the terminal in a measurement report (MR); The second determining unit is configured to determine the moving speed of the terminal based on the AOA value and the TA value reported by the terminal if it is determined that the terminal is located at the edge of the serving cell and is moving away from the serving cell. The predicting unit is configured to predict a neighbor cell that the terminal will enter and time information of the terminal entering the neighbor cell based on the location, the moving speed and the moving direction of the terminal. The sending unit is configured to send a CSI-RS issuing request to the neighbor cell, the CSI-RS issuing request carrying CSI-RS requirement information of the terminal and the time information of the terminal entering the neighbor cell, the CSI-RS issuing request being used to request the neighbor cell to make preparation for CSI-RS issuing in advance for the terminal and to issue the CSI-RS to the terminal after the terminal enters the neighbor cell.

14. A non-transitory readable storage medium, characterized in that, The non-transitory readable storage medium stores a computer program, and the computer program is used to make the processor execute the method in any one of claims 1 to 6.

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