CN110212958B

CN110212958B - Channel information feedback method and device in mobile communication system

Info

Publication number: CN110212958B
Application number: CN201910380219.1A
Authority: CN
Inventors: 马莉
Original assignee: Shanghai Langbo Communication Technology Co Ltd
Current assignee: Shanghai Langbo Communication Technology Co Ltd
Priority date: 2013-05-21
Filing date: 2013-05-21
Publication date: 2021-03-26
Anticipated expiration: 2033-05-21
Also published as: CN110212958A; CN104184537B; CN104184537A

Abstract

The invention provides a method for feeding back channel state information in a large-scale multi-input multi-output system. In one embodiment, the method comprises: the UE detects a plurality of downlink reference signal ports, and the feedback part feeds back the indexes of the reference signal ports with better channel quality to assist the uplink receiving precoding operation. By using the technical scheme provided by the invention, the problem of CSI feedback in a Massive MIMO system is solved, the problem of pilot pollution is avoided by supporting uplink receiving precoding, in addition, the calculation complexity required by uplink channel estimation is greatly reduced, and simultaneously, the compatibility with the existing system is maintained to the greatest extent.

Description

Channel information feedback method and device in mobile communication system

The present application is a divisional application of the following original applications:

application date of the original application: year 2013, 05 and 21

- -application number of the original application: 201310192163.X

The invention of the original application is named: channel information feedback method and device in mobile communication system

Technical Field

The present invention relates to a channel information feedback scheme in the technical field of mobile communication, and in particular, to a downlink channel information feedback scheme in a mobile communication system using a large-scale Multiple Input Multiple Output (Massive MIMO-Massive Multiple Input Multiple Output) technology.

Background

In a conventional 3 GPP-3 rd Generation Partner Project (3 GPP-3 rd Generation Partner Project) Long Term Evolution (LTE-Long Term Evolution) system, there are two main ways for CSI feedback of MIMO channel

Feeding back implicit CSI

User Equipment (UE-User Equipment) obtains a Channel Impulse Response (CIR-Channel Impulse Response) by detecting a Cell-specific Reference Signal (CRS-Cell specific Reference Signal) or a Channel state indication Reference Signal (CSI-RS) and maps the Channel Impulse Response (CIR-Channel Impulse Response) to implicit CSI, including information such as Precoding Matrix Indicator (Precoding Matrix Indicator). And the system side obtains the spatial correlation of the MIMO downlink channel through the PMI fed back by the UE.

Fig. 1 is a CSI-RS pattern based on Normal Cyclic Prefix (Normal CP-Normal Cyclic Prefix) in an existing LTE system-which simultaneously marks CRS and Demodulation Reference Signal (DMRS-Demodulation Reference Signal), wherein one cell is a Resource Element (RE-Resource Element) which is the minimum Resource unit of LTE. The diagonal marked REs may be used to transmit CSI-RS. The LTE system defines RS resources using the concept of ports: one RS port may be mapped to one physical antenna, or multiple physical antennas may be combined and superimposed to form one virtual antenna.

LTE defines 3 CSI-RS port numbers: 2, 4, 8, RE with numbers in fig. 1 illustrates an example of a pattern for a set of 8CSI-RS ports, the numbers indicating port indices.

Feedback uplink listening Reference Signal (SRS-Sounding Reference Signal)

And the UE sends the uplink SRS, the system side obtains the uplink CSI by demodulating the SRS, and then obtains the downlink CSI according to the link symmetry. The method is mainly suitable for a Time Division Duplex (TDD-Time Duplex Division) system.

Massive MIMO has recently become a research hotspot as a new cellular network antenna architecture. A typical characteristic of the Massive MIMO system is that a series of gains are obtained by increasing the number of antenna array elements to a larger value, for example, the system capacity theoretically continuously increases as the number of antennas increases; coherent superposition of transmit antenna signals reduces transmit power, and so on. One challenge faced by Massive MIMO is how to ensure that the transmitting end accurately obtains Channel state indication (CSI-Channel Status Indicator) information.

At present, the main research on Massive MIMO is based on a TDD system, that is, the system side obtains downlink CSI by using SRS and link symmetry. In consideration of the actual deployment scenario, the following problems still need to be solved:

1. the pilot pollution-the channel estimation of the target SRS is interfered by other SRS sequences, and particularly, the non-orthogonal SRS from the neighboring cell interferes with the system side to estimate the CIR, which includes an interference component directed to the neighboring UE, thereby forming inter-cell interference.

2. complexity-Massive MIMO systems may have hundreds of antennas, and estimating the CIR independently for each antenna requires a significant amount of computational complexity.

3. Frequency Division Duplex (FDD-Frequency Division Duplex) system CSI feedback-FDD system is still the mainstream cellular network deployment scheme at present, and in order to ensure smooth evolution of FDD, Massive MIMO CSI feedback in FDD scenarios still needs an effective solution.

Disclosure of Invention

The invention discloses a method for carrying out communication in User Equipment (UE) of a multi-input multi-output system, which comprises the following steps:

-receiving downlink reference signals of S ports

-selecting N of said S ports for a bandwidth F

-feedback Beam Selection Vector (BSV-Beam Selection Vector) indicates N ports for bandwidth F

Wherein:

the S is a positive integer larger than 1, the N is a positive integer smaller than or equal to the S, and the bandwidth F is a system bandwidth or a part of the system bandwidth. The S is configured by a high layer or physical layer signaling, the N is configured by the high layer or physical layer signaling or predefined, the N is less than or equal to the S, and the bandwidth F is a system bandwidth or a part of the system bandwidth and is configured by the high layer or physical layer signaling or predefined.

Specifically, according to one aspect of the present invention, each of the N ports has a higher link quality within the bandwidth F than the S-N ports that are not recommended, and the link quality is obtained by detecting at least one of the following parameters:

-average received power E of the downlink reference signal over Resource Elements (RE) within the bandwidth F_rsrp

-said E_rsrpDividing by an average received power E of an Orthogonal Frequency Division Multiplexing (OFDM-Orthogonal Frequency Division Multiplexing) symbol in which the downlink reference signal is located on Resource Elements (REs) within the bandwidth F_rssiThe resulting ratio E_rsrq

As described aboveE_rsrpRepresents the Reference Signal received Power (RSRP-Reference Signal Receiving Power), which is the average of the received Signal Power over all REs carrying the Reference Signal; above E_rssiThe Received Signal Strength Indicator (RSSI-Received Signal Strength Indicator) representing the OFDM symbol in which the reference Signal is located is an average value of powers of all signals (including pilot signals and data signals, adjacent cell interference signals, noise signals and the like) Received in the OFDM symbol in which the downlink reference Signal is located, and E is described above_rsrqIs the above-mentioned E_rsrpAnd the above-mentioned E_rssiThe ratio of (a) to (b). The BSV is fed back by adopting a mode of mapping S bits or by adopting a mode of mapping S bits

The mode of encoding the N indicated port indexes by a bit is fed back, wherein

Represents the smallest integer not less than X.

As an embodiment of the present invention, the UE obtains the S value of 8 and the positions of the downlink reference signals of the corresponding 8 ports through a Radio Resource Control (RRC-Radio Resource Control) signaling, predefines the N value of 4, and obtains the bandwidth F as one sub-bandwidth in the system bandwidth through a dynamic signaling. UE receives downlink reference signals of 8 ports, and calculates E of each port on the sub-bandwidth_rsrpValue, select the largest of 8 ports with said E_rsrpIndexes of 4 ports of values, which are fed back by the BSV. The BSV is a vector of 8 bits, where each bit is used to indicate whether one downlink reference signal port belongs to one of the N downlink reference signal ports.

As another embodiment of the present invention, the UE obtains the S value of 16 and the positions of the downlink reference signals of the corresponding 16 ports through RRC signaling, obtains the N value of 2 through RRC signaling, and predefines the bandwidth F as the system bandwidth. UE receives downlink reference signals of 16 ports, and calculates E of each port on a part of sub-bandwidths of system bandwidth_rsrpValue, select the largest of 16 ports with said E_rsrpAnd performing uplink feedback on the indexes of the 2 ports of the value through the BSV. The BSV is a vector formed by 8 bits, wherein every 4 bits are used to indicate a downlink port index.

Specifically, according to an aspect of the present invention, the downlink reference signal is subjected to a precoding operation, where precoding vectors corresponding to the N ports are v respectively₁ v₂ … v_N。

The precoding operation is to multiply the column vector formed by the signals to be transmitted by the physical antenna by the precoding row vector to form a downlink reference signal port, and the specific operation is completed by the system side. The number of ports formed by precoding operation may not be equal to the number of physical antennas, and for a Massive MIMO system, considering resource overhead occupied by reference signals, the S is generally smaller than the number of physical antennas.

As an embodiment of the present invention, the UE receives 8 reference signal ports, which are logical antenna ports formed after 128 physical antennas are precoded by 8 precoding vectors, and the UE selects 4 antenna ports from the logical antenna ports and indicates them in the uplink BSV feedback.

Specifically, according to one aspect of the present invention, the method further comprises the following steps:

-feedback uplink Sounding Reference Signal (SRS)

TDD systems have obvious link symmetry, so that the uplink channel CIR obtained by demodulating SRS can be directly applied to downlink transmission. For FDD, due to the difference in the uplink and downlink frequency bands, some statistical properties of the channel obtained from SRS may be used for downlink transmission, such as the covariance matrix of the channel.

-selecting a Precoding Matrix Indication (PMI) within the bandwidth F for the N ports;

-feeding back the PMI

The PMI selection criteria includes a maximum channel capacity or a maximum Signal to Interference Noise Ratio (SINR-Signal to Interference Noise Ratio).

As an embodiment of the present invention, a user equipment u having k receiving antennas detects S downlink reference signal ports and indicates N of the downlink reference signal ports through a BSV, where a downlink channel matrix of the N reference signal ports in the bandwidth F is a k-row N-column matrix H_k×NSaid user equipment u searches in a predefined codebook space for a codeword W of N rows and r columns with maximum channel capacity within said bandwidth F_N×rWhere r is the precoding rank number. The user equipment sends the W_N×rIndex PMI feedback.

Specifically, according to one aspect of the present invention, the downlink reference signal of each port reuses a pattern of channel state indication reference signals (CSI-RS).

The CSI feedback for the MIMO channel in the LTE system is implemented by demodulating CSI-RS, and therefore, the downlink reference signal may use CSI-RS resources, for example, CSI-RS resources of a normal CP, i.e. REs indicated by oblique lines in fig. 1. Further, in order to be compatible with the existing protocol as much as possible, the downlink reference signal pattern reuses the existing CSI-RS pattern. The number of supported downlink reference signal ports is 2, 4 or 8 ports.

As an embodiment of the present invention, the UE obtains 8 downlink reference signal ports to be detected according to RRC signaling, where the 8 reference signal ports are distributed in one subframe (1ms), and reuses the CSI-RS pattern as indicated by the number in fig. 1, where the number is the port index.

Specifically, according to an aspect of the present invention, the downlink reference signals of the S ports are mapped to K subframes, where K is a positive integer, and K is configured by signaling. The signaling may be higher layer signaling, physical layer signaling or implicit signaling (i.e., predefined K).

The number of physical antennas of the Massive MIMO system generally far exceeds the number of reference signal ports that can be accommodated by one subframe (one subframe can accommodate 8CSI-RS ports in the LTE system), and a small number of precoding vectors are used to convert physical antennas into logical antennas and map the logical antennas to the reference signal ports in one subframe, which may cause a loss of spatial freedom, so that the UE cannot select an optimal or suboptimal antenna port. Therefore, the downlink reference signals of the S ports may be mapped to K subframes, where K is a positive integer, and a specific value of K is configured by signaling.

As an embodiment of the present invention, the UE detects 24 downlink reference signal ports, where the 24 ports are distributed in 3 subframes, and each subframe has 8 ports, as shown in fig. 2.

Specifically, according to an aspect of the present invention, the observation window of the downlink reference signal is configured through signaling. The signaling may be higher layer signaling, physical layer signaling or implicit signaling (i.e., predefined observation window length).

The precoding vector corresponding to the downlink reference signal which can be detected by the UE can be further increased by configuring the observation window of the downlink reference signal through high-layer or physical layer signaling. And the UE detects a downlink reference signal port in the observation window and selects a corresponding BSV or a corresponding PMI. By adopting different precoding vectors in different observation windows, the UE can detect more reference signal ports mapped by the precoding vectors in the coherent time. Further, the system side may continuously optimize and allocate a precoding vector of a downlink reference signal port of the UE according to the received BSV and SRS or PMI.

As an embodiment of the present invention, a UE detects 40 downlink reference signal ports, where the 40 ports are distributed in 5 subframes, and each subframe has 8 ports; meanwhile, the UE obtains an observation window of the downlink reference signal according to the RRC signaling, which is 10 milliseconds (ms-milli-second). Then for each port, it may transmit twice within 10ms of the observation window, and the UE selects the BSV and PMI based on the twice transmitted downlink reference signals.

The invention discloses a method for carrying out communication in system equipment of a multi-input multi-output system, which comprises the following steps:

precoding the downlink reference signals of S ports

-transmitting the downlink reference signal

-receiving a Beam Selection Vector (BSV) for a bandwidth F obtaining N port indications of the S ports

Wherein:

The system devices include but are not limited to base stations, relays, home base stations, micro-cells and other devices; the signaling is either higher layer signaling or physical layer signaling.

In particular, according to one aspect of the invention, each of said N ports has a higher link quality within said bandwidth F compared to the S-N ports that are not indicated, said link quality being obtained by detecting at least one of the following parameters:

-said E_rsrpDividing by an average received power E of an Orthogonal Frequency Division Multiplexing (OFDM) symbol in which the downlink reference signal is located on Resource Elements (REs) within the bandwidth F_rssiThe resulting ratio E_rsrq

Specifically, according to an aspect of the present invention, the downlink reference signal is subjected to a precoding operation, where precoding vectors corresponding to the N ports are v respectively₁ v₂ … v_N

As an embodiment of the invention, the system equipment has 128 physical antennas, and the transmitted signals before precoding form a vector s of 128 rows and 1 columns_128×1Where each vector element is the same. The system equipment further selects 8 precoding vectors v₁ v₂ … v₈Wherein each vector is 1 row and 128 columns, and the precoding vectors are respectively multiplied by the s_128×18 logical antenna ports can be obtained, and each logical antenna port is mapped to one downlink reference signal port. V is₁ v₂ … v₈It is a matter of implementation of the system equipment that the typical precoding vectors remain orthogonal to each other. However, for Massive MIMO systems, random precoding vectors also have a near-orthogonal property. For system devices deployed outdoors, for example, a 120-degree free space may be divided into a plurality of small-angle spaces, for example, 15-degree covered spaces, with each precoding vector covering one of the small-angle spaces. The physical antenna direct transmission signal can be considered as a special precoding vector, namely, a column vector of 128 rows and 1 columns formed by 127 0 s and 1 s, wherein the position of 1 determines the physical antenna for transmitting the signal.

-uplink Sounding Reference Signal (SRS) received for physical antenna according to said v₁ v₂ … v_NPerforming receive precoding to obtain N sets of equivalent SRSs

-obtaining N groups of equivalent channel parameters by performing channel estimation according to the equivalent SRS

The equivalent channel parameters are parameters such as CIR, precoding matrix or covariance matrix between the logical antenna represented by the downlink reference port and the UE.

As an embodiment of the present invention, the system side performs receive precoding on SRS signals, that is, determines several beams with better transmission quality according to the received BSVs, then performs receive precoding on the received SRS according to corresponding precoding vectors to obtain an equivalent SRS, and performs channel estimation on the equivalent SRS to obtain CIRs of the N groups of equivalent channels. Compared with the method that each physical antenna at the system side directly carries out channel estimation, the method has the following advantages:

greatly reducing the implementation complexity of the channel estimation

The signal strength of the received SRS is enhanced, and the problem of pilot pollution is effectively avoided

This embodiment is particularly suitable for TDD systems because of the link symmetry.

-receiving Precoding Matrix Indications (PMIs) within the bandwidth F for the N ports

-calculating equivalent channel information from the BSV and the PMI

The equivalent channel information is channel information such as an actual precoding matrix, a covariance matrix and the like between a physical antenna of the system side equipment and the UE.

Unlike SRS, feedback of PMI is applicable to FDD and TDD systems. As an embodiment of the invention, a system side configures 8 reference signal ports for a UE, obtains index indications of 4 reference signal ports by receiving BSV, and the corresponding precoding vector is v₁ v₂ v₃ v₄. Further, the system side receives a precoding matrix W indicated by PMI_4×rWhere r is the precoding rank. The system side considers the actual precoding matrix of the UE in the bandwidth F as [ v [ ]₁ v₂ v₃ v₄]Multiplying by W_4×r。

Specifically, according to an aspect of the present invention, the downlink reference signals of S ports are mapped to K subframes, where K is a positive integer, and K is configured by a high layer or physical layer signaling.

As an embodiment of the present invention, a system side configures a UE to detect 64 downlink reference signal ports of 8 subframes, feeds back BSV to indicate 4 port indexes therein, and feeds back a corresponding PMI, and the system side predefines an observation window of the downlink reference signal to be 1 ms. The system side selects 64 precoding vectors for 128 physical antennas, and in each subframe (1ms), 8 downlink reference signal ports are used, and 8 downlink subframes are used in total to traverse all 64 precoding vectors. The system side obtains 4 equivalent precoding matrixes (matrix formed by precoding vectors indicated by BSV multiplied by precoding matrix indicated by PMI) preferred by the UE in 64 spatial degrees of freedom in 8 subframes.

The invention also discloses a user equipment, comprising:

a first module: receiving downlink reference signals of S ports;

a second module: selecting N ports of the S ports for a bandwidth F;

a third module: the feedback Beam Selection Vector (BSV) indicates N ports for bandwidth F.

Wherein:

As an embodiment, the above apparatus further includes:

a fourth module: feeding back an uplink Sounding Reference Signal (SRS).

As another embodiment, the above apparatus further includes:

a fifth module: selecting a Precoding Matrix Indication (PMI) within the bandwidth F for the N ports;

a sixth module: feeding back the PMI

The invention also discloses a network side device, comprising:

a first module: precoding downlink reference signals of S ports

A second module: transmitting the downlink reference signal

A third module: receiving a Beam Selection Vector (BSV) for a bandwidth F obtains N port indications of the S ports.

Wherein:

As an embodiment, the above apparatus further includes:

a fourth module: according to the v, uplink Sounding Reference Signal (SRS) received by physical antenna₁ v₂ … v_NAnd performing receiving precoding to obtain N groups of equivalent SRSs.

A fifth module: and performing channel estimation according to the equivalent SRS to obtain N groups of equivalent channel parameters.

As another embodiment, the above apparatus further includes:

a sixth module: receiving Precoding Matrix Indications (PMIs) within the bandwidth F for the N ports.

A seventh module: and calculating equivalent channel information according to the BSV and the PMI.

The invention solves the problem of CSI feedback in a Massive MIMO system, avoids the problem of pilot pollution by supporting uplink receiving precoding, greatly reduces the calculation complexity required by uplink channel estimation and simultaneously maintains the compatibility with the existing system to the maximum extent.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments made with reference to the following drawings:

fig. 1 shows one example of a CSI-RS pattern of an existing LTE system;

fig. 2 is a diagram illustrating a downlink reference signal mapped to a plurality of subframes according to an embodiment of the present invention;

FIG. 3 shows a flow diagram of base station and UE interaction according to one embodiment of the invention;

fig. 4 shows a block diagram of a processing device used in a UE according to an embodiment of the invention;

fig. 5 shows a block diagram of a processing device for use in a base station according to an embodiment of the invention;

Detailed Description

The technical solutions of the present invention will be further described in detail with reference to the accompanying drawings, and it should be noted that the features of the embodiments and examples of the present application may be arbitrarily combined with each other without conflict.

Example 1

Embodiment 1 is a flow chart of base station and UE interaction, as shown in fig. 3. In fig. 3, the downlink reference signal port S and the corresponding pattern and the port number N indicated by the BSV are configured by signaling.

The base station device D100 performs precoding operation on the downlink reference signals of S ports in step S101, and sends the downlink reference signals of S ports to the UE device D200 in step S102. The UE device D200 receives the downlink reference signals in the system bandwidth of the S ports in step S201, then selects N ports with better transmission quality in the system bandwidth in step S202, and then feeds back the BSV in step S203. The base station apparatus D100 receives the BSV in step S103. The UE device D200 feeds back the SRS in step S204, and the base station device D100 performs reception precoding on the SRS according to the precoding vector of the BSV indication port in step S104 to obtain N groups of equivalent SRSs, and then performs channel estimation on the equivalent SRS in step S105.

It should be noted that step S203 and step S204 do not have a strict timing relationship, because step S204 can serve other purposes, such as uplink scheduling, and step S204 can be periodic transmission or aperiodic transmission.

Example 2

Embodiment 2 is a block diagram of a processing apparatus used in a UE, as shown in fig. 4. In fig. 4, the UE apparatus 300 includes a receiving apparatus 301, a selecting apparatus 302, and a transmitting apparatus 303. Wherein the receiving device 301 receives downlink reference signals of S ports, the selecting device 302 selects N ports with better channel quality according to RSRP or RSRQ, and the sending device 303 sends BSVs indicating indexes of the N ports.

Example 3

Embodiment 3 is a block diagram of a processing apparatus used in a UE, as shown in fig. 4. In fig. 4, the UE apparatus 300 includes a receiving apparatus 301, a selecting apparatus 302, and a transmitting apparatus 303. Wherein the receiving device 301 receives downlink reference signals of S ports, the selecting device 302 selects N ports with better channel quality according to RSRP or RSRQ, further selects PMIs of the N ports according to a maximum channel capacity criterion, and the sending device 303 sends BSVs indicating indexes of the N ports and the PMIs.

Example 4

Embodiment 4 is a block diagram of a processing apparatus used in a base station (eNB), as shown in fig. 5. In fig. 5, the eNB apparatus 400 includes an operating device 401, a transmitting device 402, a receiving device 403, and a computing device 404. The operation device 401 pre-codes reference signals of S ports, the sending device 402 sends the reference signals, the receiving device 403 receives BSVs and N port PMIs indicated by the BSVs, and the computing device 404 is configured according to the BSVs and equivalent channel information at the PMI recovery location.

It will be understood by those skilled in the art that all or part of the steps of the above methods may be implemented by instructing relevant hardware through a program, and the program may be stored in a computer readable storage medium, such as a read-only memory, a hard disk or an optical disk. Alternatively, all or part of the steps of the above embodiments may be implemented by using one or more integrated circuits. Accordingly, the module units in the above embodiments may be implemented in a hardware form, or may be implemented in a form of software functional modules, and the present application is not limited to any specific form of combination of software and hardware.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for communication in User Equipment (UE) of a multiple-input multiple-output system comprises the following steps:

-receiving downlink reference signals of S ports;

-selecting N of said S ports for a bandwidth F;

-the feedback beam selection vector BSV indicates N ports for the bandwidth F;

wherein S is a positive integer greater than 1, N is a positive integer less than or equal to S, and the bandwidth F is a part of the system bandwidth; the downlink reference signals use CSI-RS resources, and the downlink reference signals of the S ports are sent by the same base station.

2. The method of claim 1, wherein;

each of the N ports has a higher link quality within the bandwidth F than the S-N ports that are not recommended, the link quality being obtained by detecting at least one of:

-average received power E of the downlink reference signal over resource elements RE within the bandwidth F_rsrp；

-said E_rsrpDividing by the average received power E of the resource element RE in the bandwidth F of the OFDM symbol where the downlink reference signal is located_rssiThe resulting ratio E_rsrq。

3. The method of claim 1, wherein the downlink reference signals are precoded, and wherein the precoding vectors corresponding to the N ports are v respectively₁，v₂……v_N(ii) a Or the downlink reference signals of the S ports are mapped to K subframes, where K is a positive integer and is configured by signaling.

4. The method of claim 1, further comprising the steps of:

-feeding back an uplink sounding reference signal, SRS.

5. The method of claim 1, further comprising the steps of:

-selecting a precoding matrix indication, PMI, within the bandwidth F for the N ports;

-feeding back the PMI.

6. A method for communication in a system device of a multiple-input multiple-output system, comprising the steps of:

-precoding the downlink reference signals of the S ports;

-transmitting the downlink reference signal;

-receiving a beam selection vector BSV for a bandwidth F obtaining N port indications of the S ports;

7. The method of claim 6, wherein each of the N ports has a higher link quality within the bandwidth F than the S-N ports that are not indicated, the link quality obtained by detecting at least one of:

8. The method of claim 6, wherein the downlink reference signal is passed throughPrecoding operation, wherein precoding vectors corresponding to the N ports are v respectively₁，v₂……v_N(ii) a Or the downlink reference signals of the S ports are mapped to K subframes, where K is a positive integer and is configured by signaling.

9. The method of claim 8, further comprising the steps of:

-uplink sounding reference signal, SRS, received by a physical antenna according to said v₁，v₂……v_NExecuting receiving precoding to obtain N groups of equivalent SRSs;

-performing channel estimation according to the equivalent SRS to obtain N groups of equivalent channel parameters.

10. The method of claim 6, further comprising the steps of:

-receiving precoding matrix indication, PMIs, within the bandwidth F for the N ports;

-calculating equivalent channel information from the BSV and the PMI.

11. A user equipment, characterized in that the equipment comprises:

a first module: receiving downlink reference signals of S ports;

a second module: selecting N ports of the S ports for a bandwidth F;

a third module: the feedback beam selection vector BSV indicates N ports for bandwidth F;

12. The user equipment of claim 11, wherein the device further comprises:

a fourth module: and feeding back an uplink Sounding Reference Signal (SRS).

13. The user equipment of claim 11, wherein the device further comprises:

a fifth module: selecting a precoding matrix indication, PMI, for the N ports within the bandwidth F;

a sixth module: feeding back the PMI.

14. The user equipment of claim 11, wherein;

15. The UE of claim 11, wherein the downlink reference signals are precoded, and wherein the precoding vectors corresponding to the N ports are v respectively₁，v₂……v_N(ii) a Or the downlink reference signals of the S ports are mapped to K subframes, where K is a positive integer and is configured by signaling.

16. A network side device, comprising:

a first module: precoding downlink reference signals of S ports;

a second module: transmitting the downlink reference signal;

a third module: receiving a beam selection vector, BSV, for a bandwidth, F, to obtain N port indications of the S ports;

wherein, S is a positive integer greater than 1, N is a positive integer less than or equal to S, and the bandwidth F is a part of the system bandwidth; the downlink reference signals use CSI-RS resources, and the downlink reference signals of the S ports are sent by the same base station.

17. The network-side device of claim 16, further comprising:

a fourth module: precoding vectors v corresponding to the N ports for uplink sounding reference signals SRS received by the physical antenna₁，v₂……v_NExecuting receiving precoding to obtain N groups of equivalent SRSs;

18. The network-side device of claim 16, further comprising:

a sixth module: receiving Precoding Matrix Indication (PMI) within the bandwidth F for the N ports;

19. The network-side device of claim 16, wherein each of the N ports has a higher link quality within the bandwidth F than S-N ports that are not indicated, the link quality obtained by detecting at least one of:

20. The network-side device of claim 16, wherein the network-side device is configured to perform the method of the present inventionThe downlink reference signals are subjected to precoding operation, wherein precoding vectors corresponding to the N ports are v respectively₁，v₂……v_N(ii) a Or the downlink reference signals of the S ports are mapped to K subframes, where K is a positive integer and is configured by signaling.