JP2019508941A - Multi-antenna transmission method, base station and user terminal - Google Patents

Abstract

  In the embodiments of the present application, a multi-antenna transmission method, a base station and a user terminal are disclosed. This method, when applied to a base station, divides the antenna array into at least two antenna sub-arrays, and for each antenna sub-array based on the received first uplink signal transmitted from the user terminal (UE) The transmission side correlation parameter of is estimated, and for each antenna sub array, beamforming is performed on the downlink reference signal based on the transmission side correlation parameter, and the downlink reference signal after beamforming is determined by the antenna sub array. Including transmitting to the UE. A method, a base station, and a user terminal according to embodiments of the present application can provide a multi-antenna transmission scheme that achieves both performance and complexity.

Description

  The present application relates to the field of communications, and in particular to a multi-antenna transmission method, a base station and a user terminal.

  In a wireless communication system, there are many simultaneous users who want to communicate with a base station and receive services. In these scenarios, it is feasible to schedule multiple users simultaneously with a multi-user multiple-input multiple-output (MU-MIMO) transmission scheme. With the development of antenna technology, large-scale antenna array systems (AAS) are gradually being applied to base stations. Such large scale AASs typically comprise hundreds of antenna array elements (e.g. 128, 256 or more). These array elements may be arranged in a planar manner and used as a planar array antenna. By mounting the AAS on the base station side, it is possible to simultaneously provide wireless communication to more users.

  When using large-scale AAS in the limited space at the base station side, the spatial correlation of the radio propagation channel is high, especially in the case of densely distributed user scenarios. In this case, in order to guarantee the system capacity of the wireless communication system, theoretically, multi-antenna transmission can be performed by a non-linear precoding method. However, the implementation complexity of the non-linear precoding method becomes unacceptable as the number of antennas increases. Thus, for high spatial correlation scenarios, it is necessary to design a low complexity multi-antenna transmission scheme.

  In the embodiments of the present application, a multi-antenna transmission method, a base station, and a user terminal, which are applicable to high spatial correlation scenarios and have low computational complexity and system performance, are provided.

Specifically, the embodiment of the present application is realized as follows.
A multi-antenna transmission method, applied to a base station, dividing an antenna array into at least two antenna sub-arrays, each antenna based on a received first uplink signal transmitted from a user terminal (UE) A transmitter correlation parameter indicating spatial correlation between different transmitter radio propagation channels for each subarray is estimated, and for each antenna subarray, a beam for the downlink reference signal is generated based on the transmitter correlation parameter. Performing forming and transmitting a downlink reference signal after beamforming to the UE by the antenna sub-array.

  A base station comprising a processor and a memory connected to the processor, the memory including a plurality of division modules, a reception module, an estimation module, a beamforming module, and a transmission module When the command module is stored and the command module is executed by the processor, the following processing is performed, the dividing module divides the antenna array into at least two antenna sub-arrays, and the receiving module is a user terminal Receive the first uplink signal transmitted from (UE), and the estimation module performs spatial correlation between different transmission side radio propagation channels for each antenna sub array based on the received first uplink signal Estimating a transmitter correlation parameter indicative of flexibility, the beamforming module Beamforming is performed on the downlink reference signal based on the transmission side correlation parameter for each antenna sub array to obtain a downlink reference signal after beamforming, and the transmission module performs the downlink reference signal after beamforming. , Transmit to the UE by means of a corresponding antenna sub-array.

  A user terminal comprising: a processor; and a memory connected to the processor, wherein the memory stores a plurality of command modules including a transmitting module and a receiving module, the command module being the processor When performed, the following processing is performed, and the transmission module receives the first uplink signal by transmitting the first uplink signal to the base station in which the antenna array is divided into at least two antenna sub-arrays; Transmitting side correlation parameter indicating spatial correlation between radio transmitting channels on different transmitting sides for each antenna sub array based on the first upstream signal, and the transmitting side correlation for each antenna sub array Beamforming is performed on the downlink reference signal based on the reliability parameter, and downlink reference after beamforming No. and by the antenna sub-array, so as to transmit to the user terminal, wherein the receiving module from the base station, receives the downlink reference signal after beamforming.

  A non-volatile computer readable storage medium in which machine readable instructions are stored, the machine readable instructions dividing an antenna array into at least two antenna sub-arrays and transmitting received from a user terminal (UE) Transmitting side correlation parameter indicating spatial correlation between radio transmitting channels on different transmitting sides for each antenna sub array based on the first upstream signal, and the transmitting side correlation for each antenna sub array The processor is executable to perform beamforming on the downlink reference signal based on the sex parameter and to transmit the beamformed downlink reference signal to the UE by the antenna sub-array .

  As can be seen from the above solution, the multi-antenna transmission method, the base station and the user terminal provided in the embodiments of the present application divide and receive the antenna array into at least two antenna sub-arrays by the base station, Based on the uplink signal transmitted from the UE, the transmission side correlation parameter for each antenna sub array is estimated, and for each antenna sub array, beamforming is performed on the downlink reference signal based on the transmission side correlation parameter , BRS transmitted by the antenna sub-array to the UE. Compared to performing beamforming on the entire antenna array in the prior art, computational complexity can be reduced, AAS is used, and it is applicable to a densely distributed user scenario, and high spatial correlation For certain scenarios, a multi-antenna transmission scheme is provided that combines performance and complexity.

FIG. 6 is a schematic diagram of a flow of a method in which a base station side performs multi-antenna transmission in some embodiments of the present application. FIG. 7 is a schematic view of antenna sub-array partitioning in some embodiments of the present application. FIG. 7 is a schematic view of antenna sub-array splitting in some other embodiments of the present application. FIG. 7 is a schematic view of antenna sub-array splitting in some other embodiments of the present application. FIG. 7 is a schematic view of antenna sub-array splitting in some other embodiments of the present application. It is a schematic diagram of the flow of the method in which the base station side performs multi-antenna transmission in other some Examples of this application. FIG. 7 is a schematic diagram of signaling exchange of a multi-antenna transmission method in some embodiments of the present application; FIG. 7 is a schematic diagram of a flow of a method in which the UE side performs multi-antenna transmission in some embodiments of the present application. FIG. 6 is a schematic diagram of a base station configuration in some embodiments of the present application. It is a schematic diagram of a structure of the base station in the other one part Example of this application. FIG. 6 is a schematic view of a configuration of a user terminal in some embodiments of the present application.

  In order to make the object, means of solution, and merits of the present invention clearer, the present invention will be described in more detail by way of examples with reference to the drawings.

  FIG. 1 is a schematic diagram of a flow of the multi-antenna transmission method in some embodiments of the present application. This method is applied to a base station. As shown in FIG. 1, the method includes the following steps.

  At step 101, the antenna array is divided into at least two antenna sub-arrays.

  In some embodiments of the present application, the division method of the antenna sub-array includes dividing the antenna array based on at least one of the configuration of the antenna array and the polarization direction of the antenna array element, although there are a plurality. For example, uniform division or non-uniform division may be performed based on the configuration of the antenna array. Alternatively, based on the polarization direction of the antenna array elements, antenna array elements having similar polarization directions are divided into one antenna sub-array. Alternatively, uniform division or non-uniform division is performed on the antenna array in consideration of the polarization direction of the antenna array element. Here, the number of antenna array elements included in each of the antenna sub-arrays may be the same or different.

  Taking the two-dimensional antenna array as an example, FIG. 2a is a schematic view of the division of the antenna sub-array in one embodiment of the present application. Here, the antenna array 210 is uniformly divided into four antenna sub arrays 211, 212, 213, and 214. Each antenna sub-array is a regular square antenna array, each containing four antenna array elements.

  FIG. 2b is a schematic view of the antenna sub-array division in another embodiment of the present application. Here, the antenna array 210 is uniformly divided into four antenna sub-arrays 221, 222, 223, 224 in the lateral direction. Each antenna sub-array is a regular transverse band antenna array, each containing four antenna array elements.

  FIG. 2c is a schematic diagram of the antenna sub-array division in another embodiment of the present application. Here, the antenna array 210 is uniformly divided into four antenna sub arrays 231, 232, 233, and 234 in the vertical direction. Each antenna sub-array is a regular longitudinal strip antenna array, each containing four antenna array elements.

  FIG. 3 is a schematic view of antenna sub-array division in another embodiment of the present application. Here, the polarization system of the antenna array elements of the antenna array 300 includes two, vertical polarization and horizontal polarization. According to these two polarization schemes, antenna array 300 is divided into antenna sub-arrays 310 and 320 each including 16 antenna array elements. Here, the antenna array elements of the antenna sub array 310 are all vertically polarized, and the antenna array elements of the antenna sub array 320 are all horizontally polarized.

  The division method of the antenna sub array mentioned above is only an illustration, and when specifically applied, the antenna array may be divided into antenna sub arrays including different numbers of antenna array elements. For example, the 16 antenna array elements included in the antenna array 210 are divided into antenna sub-arrays including 8, 6, and 2 antenna array elements, respectively. Here, the shape of the antenna sub-array and the number of antenna array elements contained therein will affect the direction and coverage of the formed beam.

  In step 102, based on the received first uplink signal transmitted from the user terminal (UE), the transmission side correlation parameter for each antenna sub array is estimated.

  In this step, the first uplink signal may be an uplink reference signal or another uplink signal, for example, uplink data or a control signal. The transmitter correlation parameter indicates the spatial correlation between different transmitter radio propagation channels. For example, the sender correlation parameter may be represented as a sender correlation matrix.

  Taking the uplink reference signal as an example, the base station may estimate the transmission side correlation matrix for each antenna sub array based on the uplink reference signal transmitted from the UE, specifically, from the uplink reference signal to the antenna array. Calculate the entire transmitter correlation matrix and average the transmitter correlation matrices of all UEs to obtain the equivalent transmitter correlation matrix, and submatrix in the diagonal of the equivalent transmitter correlation matrix Determining as a transmission side correlation matrix for each antenna sub-array.

In one embodiment, the first uplink signal is a periodic sounding reference signal (P-SRS), and the uplink channel matrix H of the k-th user based on the P-SRS transmitted from the k-th user. Assuming that _k is estimated and the total number of users is K, the equivalent transmitter correlation matrix
Is

It becomes. Here, [] ^H represents a conjugate transpose operation.

If the entire antenna array is divided into L antenna sub-arrays, the above equivalent transmit-side correlation matrix
Furthermore,
It may be expressed as Here, the transmitter correlation matrix of the l-th antenna sub-array is
The l-th submatrix R _ll (l = 1,..., L) in the diagonal of. If the l-th antenna sub-array includes n antenna array elements, R _ll is an n * n square matrix.

  In step 103, on the basis of the transmission side correlation parameter, beamforming is performed on the downlink reference signal for each antenna sub array, and the downlink shaped reference signal (BRS: beamformed reference signal) after beam forming is transmitted by the antenna sub array. , Send to UE.

  In this step, an intrinsic parameter is calculated from the transmission side correlation parameter, and beam forming is performed on the downlink reference signal based on the intrinsic parameter to obtain BRS. Specifically, when the transmitter correlation parameter is a transmitter correlation matrix, the eigen parameter is an eigenvector corresponding to the largest eigenvalue of the transmitter correlation matrix, and / or a second largest eigenvalue of the transmitter correlation matrix It may be an eigenvector corresponding to

For example, for each antenna sub-array l = 1,..., L, its corresponding transmitter correlation matrix R _ll can be uniquely represented by the eigenvalues and eigenvectors.
As _in, performing eigenvalue decomposition (EVD) against _{R ll.} Here, Σ is an eigenvalue diagonal matrix, Q is an eigenvector matrix, and [] ⁻¹ represents an operation for ^obtaining an inverse matrix. If R _ll is full _{rank, Σ = diag (λ 1,} λ 2, ···, λ n) is the n which are arranged in descending order eigenvalues λ _1, λ _2, ···, comprises a lambda _n, eigenvectors _{Q = {χ 1, χ 2} , ···, χ n} is, n eigenvectors chi ₁ corresponding, χ _2, ···, including chi _n. The eigenvector corresponding to the largest eigenvalue λ ₁ is χ ₁ , and the eigenvector corresponding to the next large eigenvalue λ ₂ is χ ₂ .

The eigenvectors for performing beamforming on the downlink reference signal may be one or more. For example, when beamforming is performed on the downlink reference signal s _{RS, l} using the eigenvector χ ₁ corresponding to the maximum eigenvalue λ ₁ in the l-th antenna sub-array, the obtained BRS is y _{BRS, l} = χ _{It is 1} s _{RS, l} .

Alternatively, when beamforming is performed on the downlink reference signal s _{RS, l} using the eigenvector χ ₂ corresponding to the next large eigenvalue λ ₂ in the l-th antenna sub-array, the obtained BRS is y _{BRS, l} = It is χ ₂ s _{RS, l} .

_{Alternatively,} when beamforming is performed on the downlink reference signal s _{RS, l} using these two eigenvectors χ ₁ and χ ₂ , y _{BRS, l} = χ ₁ s _{RS, l} and y _{BRS2, l} = Obtain two BRSs of _{l 2} s _{RS, l} and send each to the UE. Alternatively, the obtained two BRSs may be superimposed as y _{BRS, l} = χ ₁ s _{RS, l} + χ ₂ s _{RS, l} , and the combined BRS may be transmitted to the UE.

  In the concrete application, in consideration of long-term evolution (LTE) system compatibility, the downlink reference signal may be a cell specific reference signal (CRS) or a channel state indication reference signal (CSI-RS). Good.

  A plurality of BRSs transmitted by L antenna sub-arrays are on time frequency resources by time division multiplexing (TDM), frequency division multiplexing (FDM), code division multiplexing (CDM), or cyclic shift (CS). May be multiplexed.

  In the embodiment shown in FIG. 1, the base station divides the antenna array into at least two antenna sub-arrays, and based on the received uplink signal transmitted from the UE, the transmission side correlation parameter for each antenna sub-array Is estimated, beamforming is performed on the downlink reference signal based on the transmission side correlation parameter for each antenna sub array, and the BRS is transmitted to the UE by the antenna sub array. Compared to performing beamforming on the entire antenna array in the prior art, computational complexity can be reduced, AAS is used, and it is applicable to a densely distributed user scenario, and high spatial correlation For certain scenarios, a multi-antenna transmission scheme is provided that combines performance and complexity.

  FIG. 4 is a schematic diagram of a flow of a method in which the base station side performs multi-antenna transmission in another embodiment of the present application. As shown in FIG. 4, in addition to the steps shown in FIG. 1, FIG. 4 further includes the following steps.

  In step 104, receive beam selection information fed back from the UE and schedule a user based on the received beam selection information.

  In this step, the beam selection information may be a beam identifier corresponding to the BRS selected by the UE or an antenna sub-array identifier selected by the UE. Here, the beam identifier may be an index of the beam, and the antenna sub-array identifier may be an index of the antenna sub-array.

  Specifically, when the UE receives a plurality of BRSs transmitted by the L antenna sub-arrays on the base station side, the UE selects one or more BRSs from among them, and selects one of the beams corresponding to the selected BRS. Determine the index. If the UE knows in advance the correspondence between the antenna sub-array on the base station side and the beam, the UE determines the index of the antenna sub-array corresponding to the index of the beam based on the correspondence, and the antenna sub-array The index of may be transmitted to the base station as beam selection information. When the UE does not know the specific information of the antenna sub array on the base station side, it transmits the index of the beam corresponding to the selected BRS to the base station as beam selection information.

  The base station determines the selected antenna sub-array at the UE based on the received beam selection information. If the beam selection information is an index of a beam corresponding to the BRS selected by the UE, the base station may map the antenna sub-array selected by the UE according to the correspondence between the antenna sub-array and the beam. If the beam selection information is the index of the UE selected antenna sub-array, the base station can directly determine the UE selected antenna sub-array among them.

  The method for the base station to schedule users groups the UEs based on the determined UE selected antenna sub-arrays to obtain a scheduling target UE group corresponding to each antenna sub-array, and then each scheduling Determining, for each target UE group, a scheduling user transmitting data by an antenna sub-array corresponding to the target scheduling UE group. Here, one scheduling target UE group includes one or more UEs.

  In one embodiment, grouping may be performed based on user feedback simply when grouping the users. That is, UEs fed back the index of the same antenna sub-array belong to one scheduling target UE group without performing any adjustment. For example, if there are K UEs and L antenna subarrays, UE 1 feeds back that the index of the selected antenna subarray is 1, and UE 2 has the index of 1 and the index of the selected antenna subarrays. Feed back that it is 2, UE3 feeds back that the index of the selected antenna sub-array is 1 and 3, UE4 feeds back that the index of the selected antenna sub-array is 1, and UE5 feeds back it. It is fed back that the index of the selected antenna sub-array is 1,..., UEK is assumed to feedback that the index of the selected antenna sub-array is L.

Then, the base station can obtain the results shown in Table 1. Here, there are five UEs that have selected an antenna sub-array whose index is 1, and these five UEs belong to one group. For example, a number of users are currently waiting to be scheduled within the coverage of the beam formed by the antenna sub-array, such as multiple users currently meeting in one conference room Considering the scenario, these users simultaneously requested data services from the base station, and the base station determined that the indexes of the antenna sub-arrays selected by these users are all 1's.

In another embodiment, the base station may group UEs based on the scheduling balance principle. That is, the number of scheduling target UEs assigned to each antenna sub-array is balanced so that the number of UEs in all scheduling target UE groups becomes relatively close. For example, as shown in Table 2, when the index of antenna sub-arrays fed back from a large number of UEs is 1, the base station may adjust the scheduling target UEs divided into the same group among the antenna sub-arrays as appropriate. Good. For example, it is considered to adjust between beam antenna sub-arrays so as to leave some UEs with selected antenna sub-arrays in only one group. In contrast to the results of Table 1 where no adjustment is performed, as shown in Table 2, UE4 and UE5 are assigned to the scheduling target UE groups whose corresponding indexes are 2 and 3, respectively, and the corresponding index is 1 UE3 is deleted from a certain scheduling target UE group, and UE3 is allocated only to the scheduling target UE group whose corresponding index is 3.

  If the UE also sends RSRP of BRS received at the selected antenna sub-array in addition to feeding back the index of the selected antenna sub-array to the base station, the base station will Grouping of users may be performed with reference to RSRP in a selected antenna sub-array. For example, in the above scheduling balance principle, it is considered to leave only UEs whose RSRP is higher than a certain threshold in each scheduling target UE group so that the number of scheduling target UEs assigned to each antenna sub array becomes relatively close.

  For each scheduling target UE group, the base station may determine one or more scheduling users among them based on a predetermined scheduling metric. Here, the scheduling metric may be a geometric mean of UE throughput, a proportional fairness scheduling metric, an improved proportional fairness scheduling metric.

  In step 105, by transmitting downlink control signaling to each scheduling user, transmission of a second uplink signal from each scheduling user to the base station is triggered, and based on the second uplink signal, transmission is performed for each scheduling user. Precoding data and sending the precoded data to each scheduling user.

  In this step, the second uplink signal may be an uplink reference signal such as an aperiodic sounding reference signal (A-SRS). The downlink control signaling to be transmitted has an indication bit for instructing the scheduling user to transmit an uplink reference signal. This triggers the transmission of the uplink reference signal from the scheduling user to the base station. Thereafter, the base station performs channel estimation based on the received uplink reference signal, and estimates downlink channel state information of the entire antenna array based on the channel reciprocity principle.

  In the present application, a linear precoding algorithm may be used between antenna sub-arrays since the entire antenna array is divided into multiple antenna sub-arrays and the spatial correlation of the channels between the antenna sub-arrays is weak. Thereby, good performance can be obtained. Also, within the antenna sub-array, non-linear precoding algorithms are used to adapt to high spatial correlation. That is, two precoding matrices are respectively calculated, and precoding is performed in a cascade manner.

  Specifically, from the downlink channel state information of all scheduling users, a linear precoding matrix is calculated by the linear precoding method, and this is used as a first precoding matrix. Next, from the estimated downlink channel state information and the linear precoding matrix, the non-linear precoding matrix for each scheduling user is calculated by the non-linear precoding method, and this is used as the second precoding matrix. Thereafter, data for each scheduling user is precoded based on the linear precoding matrix and the non-linear precoding matrix.

For example, linear precoding may be made to obtain linear precoding matrix P from the downlink channel state information of all scheduling users by zero forcing (ZF) or block diagonalization (BD) algorithm. Then, for each scheduling user at the antenna sub-array, a linear precoding matrix P and a downlink channel matrix
Product with
Then, for example, nonlinear precoding is performed by the THP algorithm to obtain a nonlinear precoding matrix V _k . Furthermore, based on the P and V _k, all user data to precoding twice, to obtain a precoded data.

  In one embodiment, when transmitting precoded data, the precoded data may be transmitted simultaneously to all scheduling users throughout the antenna array. In another embodiment, when each antenna sub-array corresponds to one scheduling user group, and each scheduling user group includes a plurality of scheduling users, different transmission time zones are set, one for each antenna sub-array. A transmission time zone may be designated, and then precoded data may be transmitted in a designated transmission time zone by an antenna subarray corresponding to a scheduling user, that is, it may be transmitted in a time division manner between antenna subarrays. Good.

  In the embodiment shown in FIG. 4, the base station receives the beam selection information fed back from the UE, schedules the users based on the received beam selection information, and determines the scheduling user for each antenna sub-array The spatial correlation between scheduling user groups corresponding to different antenna sub-arrays is weakened, high spatial correlation is maintained only between scheduling users corresponding to the same antenna sub-array, and linear precoding and nonlinear precoding are further performed. By performing cascade precoding in a combined manner, the gain of multi-user multiplexing is improved and cell throughput is increased.

  FIG. 5 is a schematic diagram of signaling exchange of the multi-antenna transmission method according to an embodiment of the present application. In the figure, a base station and scheduling target users UE1,..., UEK are included. As shown in FIG. 5, the method includes the following steps.

  At step 501, the base station divides the antenna array into at least two antenna sub-arrays.

  At step 502, each UE transmits a first uplink signal to the base station. For example, UE1, ..., UEK respectively transmit uplink signals P-SRS to the base station.

  In step 503, the base station estimates the transmission side correlation matrix for each antenna sub array based on the received first uplink signal transmitted from the UE, and the transmission side correlation for each antenna sub array The eigenvectors are calculated from the matrix, and beamforming is performed on the downlink reference signal based on the eigenvectors to obtain BRS.

  At step 504, the base station transmits corresponding BRSs to the UE on each antenna sub-array.

  In step 505, the UE selects an antenna sub-array based on the received BRS.

  At step 506, the UE feeds back beam selection information to the base station.

  At step 507, the base station schedules users based on the received beam selection information.

  At step 508, the base station triggers the transmission of a second uplink signal from each scheduling user to the base station by transmitting downlink control signaling to each scheduling user.

  As shown in FIG. 5, it is assumed that UE1 and UEK are scheduling users. In this case, the base station triggers the transmission of A-SRS from UE1 and UEK to the base station.

  At step 509, each scheduling user transmits a second uplink signal to the base station.

  In step 510, the base station cascades precoding data for each scheduling user based on the received second uplink signal.

  At step 511, the base station transmits the precoded data to each scheduling user.

  In one embodiment, in addition to transmitting precoded data, the base station can simultaneously use the signaling configuration information for the demodulation reference signal (DMRS) for the associated demodulation of the data channel of the UE to scheduling users. It may be sent.

  At step 512, each scheduling user detects the received downlink data and obtains data of the station from among them.

  FIG. 6 is a schematic diagram of a flow of a method in which the UE side performs multi-antenna transmission in an embodiment of the present application. As shown in FIG. 6, the method includes the following steps.

  At step 601, by transmitting the first uplink signal to the base station, the base station estimates transmission side correlation parameters for each antenna sub array based on the received first uplink signal, and each antenna The beamforming is performed on the downlink reference signal based on the transmission side correlation parameter for each sub array, and the downlink reference signal BRS after beam forming is transmitted to the user terminal by the antenna sub array. For example, the first upstream signal is P-SRS.

  In step 602, a BRS is received from a base station, and a beam is selected based on the received BRS to generate beam selection information.

  In one embodiment, the UE receives BRSs transmitted by L antenna sub-arrays on the base station side, estimates the reference signal received power (RSRP) of each BRS, and selects one or more BRSs from among them. For example, select a BRS with the largest RSRP, or select a BRS with the largest RSRP and the next largest RSRP. The UE may determine the beams corresponding to these BRSs based on the used resources of the selected BRSs.

  Furthermore, the UE may generate different beam selection information depending on whether or not the correspondence between the antenna sub array on the base station side and the beam is known. Specifically, when the UE can not know the correspondence relationship, the beam identifier corresponding to the selected BRS is fed back to the base station as beam selection information. If the UE knows the correspondence in advance, the antenna sub-array identifier may be mapped from the beam identifier based on the correspondence and the antenna sub-array identifier may be fed back to the base station as beam selection information.

  In another embodiment, in addition to feeding back beam selection information to the base station, the UE may transmit RSRP of the selected BRS together to the base station. Thereby, the base station can perform scheduling of the user with reference to the RSRP of the BRS selected by the UE.

  At step 603, feedback of beam selection information to the base station causes the base station to schedule users based on the received beam selection information.

  If the UE is a scheduling user, then further execute steps 604 and 605.

  In step 604, the base station precodes data for each scheduling user based on the second uplink signal by receiving downlink control signaling from the base station and transmitting the second uplink signal to the base station. And transmit the precoded data to each scheduling user.

  In step 605, data precoding is received from the base station and data detection is performed.

  FIG. 7 is a schematic diagram of the configuration of the base station 700 in an embodiment of the present application. As shown in FIG. 7, the base station 700 divides the antenna array into at least two antenna sub-arrays, and a receiving module 720 that receives the first uplink signal transmitted from the user terminal (UE). An estimation module 730 for estimating the transmission side correlation parameter for each antenna sub-array divided by the division module 710 based on the first uplink signal received by the reception module 720; and an estimation module 730 for each antenna sub-array Performing beamforming on the downlink reference signal based on the transmission side correlation parameter estimated in step b. To obtain the downlink reference signal after beamforming, and beamforming obtained by the beamforming module 740 After the downlink reference signal Comprising the corresponding antenna subarray, the transmission module 750 to send to the UE, the.

  FIG. 8 is a schematic diagram of a configuration of a base station 800 in another embodiment of the present application. In addition to the modules shown in FIG. 7, the base station 800 further comprises a scheduling module 760 and a precoding module 770.

  In one embodiment, the receiving module 720 further receives beam selection information fed back from the UE. In response, scheduling module 760 schedules users based on the beam selection information received at receiving module 720.

  In one embodiment, the scheduling module 760 determines the selected antenna sub-array at the UE based on the beam selection information, and groups the UE based on the scheduling balance principle and the selected antenna sub-array at the UE, A scheduling target UE group corresponding to each antenna sub array is obtained, and for each scheduling target UE group, a scheduling user for transmitting data by the antenna sub array corresponding to the scheduling target UE group is determined.

  In one embodiment, the transmitting module 750 further triggers transmission of a second uplink signal from each scheduling user to the base station by transmitting downlink control signaling to each scheduling user determined in the scheduling module 760. Do. The receiving module 720 further receives a second uplink signal transmitted from each scheduling user.

  In response, precoding module 770 precodes data for each scheduling user determined in scheduling module 760 based on the second uplink signal received in receiving module 720. The transmitting module 750 further transmits the precoded data obtained by the precoding module 770 to each scheduling user.

  In some embodiments, the precoding module 770 further estimates downlink channel state information for each scheduling user based on the second uplink signal, and determines from the downlink channel information of all scheduling users. Calculating a second precoding matrix for each scheduling user from the downlink channel state information for each scheduling user and the first precoding matrix; and Precoding data for each scheduling user based on the second precoding matrix.

  In some embodiments, the first precoding matrix is a linear precoding matrix, the second precoding matrix is a non-linear precoding matrix, and the precoding module 770 further includes the linear precoding matrix. Data for each scheduling user is precoded twice based on a matrix and the non-linear precoding matrix.

  FIG. 9 is a schematic view of the configuration of the user terminal 900 in an embodiment of the present application. As shown in FIG. 9, the user terminal 900 transmits the first uplink signal to the base station where the antenna array is divided into at least two antenna sub arrays, whereby the base station receives the first uplink signal received. Based on the transmission side correlation parameter indicating the spatial correlation between different transmission side radio propagation channels for each antenna sub array, and downlink reference based on the transmission side correlation parameter for each antenna sub array A transmitting module 910 for performing beamforming on the signal and transmitting the downlink reference signal after beamforming to the user terminal by the antenna sub-array, and receiving the downlink reference signal after beamforming from the base station And a module 920.

  In one embodiment, the user terminal 900 further comprises a selection module 930 for selecting beams and generating beam selection information based on the post-beamforming downlink reference signal received at the receiving module 920.

  In response, the transmitting module 910 further causes the base station to schedule the user based on the beam selection information by feeding back the beam selection information determined in the selection module 930 to the base station, where The base station determines an antenna sub-array selected by the user terminal based on the beam selection information, and groups the user terminal based on a scheduling balance principle and an antenna sub-array selected by the user terminal. Then, a scheduling target user terminal group corresponding to each antenna sub array is obtained.

  In some embodiments, the transmitting module 910 further transmits a second uplink signal to the base station in response to downlink control signaling transmitted from the base station, wherein the base station is configured to: A first precoding matrix and a second precoding matrix are obtained from the second uplink signal, and data of the user terminal is obtained based on the first precoding matrix and the second precoding matrix. The precoding is performed twice to obtain precoded data, and the receiving module 920 further receives the precoded data from the base station.

  Those skilled in the art should understand that the function of each processing module in the user terminal and base station of the embodiment of the present application can be understood with reference to the related description of the embodiment relating to the method described above, Each processing module in the example user terminal and base station can be realized by software for realizing the example of the present application being executed in the user terminal and the base station.

  It should be understood that, in some embodiments provided herein, the disclosed apparatus and method may be implemented in another manner. The embodiments of the device described above are merely schematic. For example, the division of the modules is only a division of logical functions, and may be another division scheme in actual implementation. For example, multiple modules or assemblies may be combined, incorporated into another system, or some configurations may be ignored or not performed. Also, the coupling or direct coupling or communication connection of each component shown or described may be through some interface, and the indirect coupling or communication connection of a device or module may be electrical , Mechanical or other forms.

  As can be understood by those skilled in the art, all or part of the steps for realizing the embodiments of the above method may be performed by instructing the relevant hardware by a program. The aforementioned program may be stored in a computer readable storage medium. In executing the program, steps are carried out which include an embodiment of the above method. The above-described storage media include various media capable of storing program codes, such as mobile storage devices, read-only memories (ROMs), random access memories (RAMs), magnetic disks and optical disks. .

  The above is only a preferred embodiment of the present application, and does not limit the protection scope of the present application. All the modifications, equivalent replacements, improvements, etc. made within the principles of the present application should be included within the protection scope of the present application.

210 antenna array 211, 212, 213, 214 antenna sub array 221, 222, 223, 224 antenna sub array 231, 232, 233, 234 antenna sub array 300 antenna array 310, 320 antenna sub array 700 base station 710 split module 720 reception module 730 estimation module 740 beam forming module 750 transmission module 760 scheduling module 770 precoding module 800 base station 900 user terminal 910 transmission module 920 reception module 930 selection module

Claims (19)

A multi-antenna transmission method applied to a base station;
Divide the antenna array into at least two antenna sub-arrays,
Based on the received first uplink signal transmitted from the user terminal (UE), a transmitter correlation parameter indicating spatial correlation between different transmitter radio propagation channels for each antenna sub array is estimated ,
Beamforming is performed on the downlink reference signal based on the transmission side correlation parameter for each antenna sub array, and the downlink reference signal after beam forming is transmitted to the UE by the antenna sub array.
A method characterized by comprising. It is possible to perform beamforming on the downlink reference signal based on the transmission side correlation parameter as follows:
The method according to claim 1, comprising: calculating an eigenparameter from the transmission side correlation parameter, and performing beamforming on the downlink reference signal based on the eigenparameter.   The transmitter correlation parameter is a transmitter correlation matrix, and the eigen parameter is an eigenvector corresponding to the largest eigenvalue of the transmitter correlation matrix, and / or a second largest eigenvalue of the transmitter correlation matrix. A method according to claim 2, characterized in that it is a corresponding eigenvector.   The method of claim 1, further comprising: receiving beam selection information fed back from the UE; and scheduling a user based on the received beam selection information. Scheduling the user based on the received beam selection information may include
Determine a selected antenna sub-array at the UE based on the beam selection information;
The UEs are grouped based on the scheduling balance principle and the antenna sub-arrays selected by the UEs to obtain a scheduling target UE group corresponding to each of the antenna sub-arrays,
For each scheduling target UE group, determine a scheduling user for transmitting data by an antenna sub-array corresponding to the scheduling target UE group,
A method according to claim 4, characterized in that Sending a second uplink signal from each scheduling user to the base station by sending downlink control signaling to each scheduling user;
Precoding data for each scheduling user based on the second uplink signal and transmitting the precoded data to each scheduling user;
The method according to claim 4 or 5, further comprising: Precoding data for each scheduling user based on the second uplink signal is:
Downlink channel state information for each scheduling user is estimated based on the second uplink signal;
A first precoding matrix is calculated from the downlink channel state information of all scheduling users,
A second precoding matrix for each scheduling user is calculated from downlink channel state information for each scheduling user and the first precoding matrix,
Precoding data for each scheduling user based on the first precoding matrix and the second precoding matrix,
A method according to claim 6, characterized in that The first precoding matrix is a linear precoding matrix, and the second precoding matrix is a non-linear precoding matrix.
Precoding data for each scheduling user based on the first precoding matrix and the second precoding matrix is:
Precoding the data for each scheduling user twice based on the linear precoding matrix and the non-linear precoding matrix,
A method according to claim 7, characterized in that. Sending the precoded data to each scheduling user is:
Set different transmission time zones, and specify one transmission time zone for each antenna sub array,
Transmitting the precoded data in a designated transmission time zone by an antenna sub-array corresponding to the scheduling user;
A method according to claim 6, characterized in that A base station,
A processor,
And a memory connected to the processor.
In the memory, a plurality of command modules including a division module, a reception module, an estimation module, a beam forming module, and a transmission module are stored, and when the command module is executed by the processor, Processing is performed,
The dividing module divides the antenna array into at least two antenna sub-arrays,
The receiving module receives a first uplink signal transmitted from a user terminal (UE),
The estimation module estimates, based on the received first uplink signal, a transmission side correlation parameter indicating spatial correlation between different transmission side radio propagation channels for each antenna sub array;
The beamforming module performs beamforming on the downlink reference signal based on the transmission side correlation parameter for each antenna sub array to obtain a downlink reference signal after beamforming.
The transmission module transmits the downlink reference signal after beamforming to the UE by a corresponding antenna sub array.
A base station characterized by The receiving module further receives beam selection information fed back from the UE,
The base station is
Further comprising a scheduling module for scheduling users based on the received beam selection information;
The base station according to claim 10, characterized in that:   The scheduling module determines an antenna sub-array selected by the UE based on the beam selection information, and groups the UE based on a scheduling balance principle and an antenna sub-array selected by the UE. A scheduling target UE group corresponding to each antenna sub array is obtained, and for each scheduling target UE group, a scheduling user to transmit data by using the antenna sub array corresponding to the scheduling target UE group is determined. Base station described in. The transmission module further triggers transmission of a second uplink signal from each scheduling user to the base station by transmitting downlink control signaling to each scheduling user,
The receiving module further receives a second uplink signal transmitted from each scheduling user,
The base station is
Further comprising a precoding module for precoding data for each scheduling user based on the received second uplink signal,
The transmitting module further transmits precoded data to each scheduling user.
The base station according to claim 11 or 12, characterized in that: The precoding module further estimates downlink channel state information for each scheduling user based on the second uplink signal,
A first precoding matrix is calculated from the downlink channel state information of all scheduling users,
A second precoding matrix for each scheduling user is calculated from downlink channel state information for each scheduling user and the first precoding matrix,
Precoding data for each scheduling user based on the first precoding matrix and the second precoding matrix,
The base station according to claim 13, characterized in that. The first precoding matrix is a linear precoding matrix, and the second precoding matrix is a non-linear precoding matrix.
The precoding module further precodes data for each scheduling user twice based on the linear precoding matrix and the non-linear precoding matrix.
The method according to claim 14, characterized in that. A user terminal,
A processor,
And a memory connected to the processor.
A plurality of command modules including a transmission module and a reception module are stored in the memory, and the following processes are executed when the command module is executed by the processor:
The transmitting module transmits the first uplink signal to the base station in which the antenna array is divided into at least two antenna sub-arrays, whereby the base station transmits each antenna based on the received first uplink signal. A transmitter correlation parameter indicating spatial correlation between different transmitter radio propagation channels for each subarray is estimated, and for each antenna subarray, a beam for the downlink reference signal is generated based on the transmitter correlation parameter. Performing forming, and transmitting a downlink reference signal after beam forming to the user terminal by the antenna sub array;
The receiving module receives a downlink reference signal after beamforming from the base station.
A user terminal characterized by Further comprising a selection module for selecting a beam and generating beam selection information based on the received downstream reference signal after beamforming,
The transmitting module further causes the base station to schedule a user based on the beam selection information by feeding back the beam selection information to the base station, wherein the base station is configured to: The antenna sub-arrays selected by the user terminal are determined based on selection information, and the user terminals are grouped based on the scheduling balance principle and the antenna sub-arrays selected by the user terminal, and each antenna sub-array is selected. Get the corresponding scheduled target user terminal group
The user terminal according to claim 16, characterized in that: The transmission module further transmits a second uplink signal to the base station in response to downlink control signaling transmitted from the base station, wherein the base station transmits the second uplink signal from the second uplink signal, Obtaining a first precoding matrix and a second precoding matrix; precoding the user terminal data twice based on the first precoding matrix and the second precoding matrix; Get the coded data,
The receiving module further receives the precoded data from the base station,
The user terminal according to claim 17, characterized in that: A non-volatile computer readable storage medium comprising
Machine readable instructions are stored on the storage medium, the machine readable instructions being
Divide the antenna array into at least two antenna sub-arrays,
Based on the received first uplink signal transmitted from the user terminal (UE), a transmitter correlation parameter indicating spatial correlation between different transmitter radio propagation channels for each antenna sub array is estimated ,
Beamforming is performed on the downlink reference signal based on the transmission side correlation parameter for each antenna sub array, and the downlink reference signal after beam forming is transmitted to the UE by the antenna sub array.
Non-volatile computer readable storage medium, characterized in that it is executable on a processor so as to complete things.