WO2012159266A1 - Self-adaptive multiple streams beamforming method and base station - Google Patents

Abstract

A self-adaptive multiple streams beamforming method and a base station are provided in the embodiments of the present invention. The method includes the following steps: the base station determines a channel matrix of a downlink according to the information transmitted by a user terminal (101); the base station calculates channel capacities corresponding to different numbers of the beamforming streams according to the channel matrix (102); according to the calculation results of the channel capacity, the base station selects the number of the beamforming streams corresponding to the maximum channel capacity to perform a downlink beamforming (103). The method and base station provided in the embodiments of the present invention, by extending a prior dual streams beamforming algorithm to the multiple streams beamforming algorithm and determines the number of the beamforming streams according to the channel capacities, realizes self-adaptive transmission of the beamforming, and increases system flexibility.

Description

 Adaptive multi-stream beamforming method and base station

 The present invention relates to the field of wireless communications, and in particular, to an adaptive multi-stream beamforming method and a base station for a downlink of a wireless communication system. Background technique

 LTE-A (LTE-Advanced, LTE-based evolution) is a candidate for the 4G standard. MIMO (Multiple-Input Multiple-Out-put) is a key technology that must be adopted in LTE-A. Compared to LTE (Long Term Evolution), multi-antenna enhanced technology is the focus of LTE-A standardization. LTE-A introduces higher antenna configuration (8Tx DL) and more advanced multi-antenna output modes, such as multi-stream, multi-user, etc. Multi-stream beamforming and multi-user MIMO technology based on this will further improve the system. Capacity and spectrum utilization.

 The beamforming technology can perform signal preprocessing according to the channel characteristics of the user, and has the ability to expand coverage, increase system capacity, and reduce interference. The receiving end of the MIMO system feeds back the channel state information CSI (Channel State Information) to the transmitting end, and then performs precoding operation on the transmission information, which can greatly improve the performance of the MIMO system.

 In the LTE protocol, MIMO/SA (Smart Antenna) technology is mainly embodied in MIMO beamforming. From single beamforming in Rel-8 to dual-beam beamforming in Rel-9, to multi-layer beamforming in LTE-A Beamforming), beamforming has shown great advantages in improving system performance. In the LTE communication system, the beamforming technology is applied to the data transmission of the PDSCH (Physical Downlink Shared Channel).

 In the process of implementing the present invention, the inventor has found that a single-user multi-stream beamforming technology can enable a single user to transmit multiple data streams at a certain time, and at the same time obtain a shaping gain and a spatial multiplexing gain, thereby obtaining A larger transmission rate than conventional single-stream beamforming techniques. Therefore, it is important to study single-user multi-stream beamforming techniques.

It should be noted that the above description of the technical background is only for the purpose of facilitating the clear and complete description of the technical solutions of the present invention, and is convenient for understanding by those skilled in the art. Can't just because these programs are in the hair The background of the prior art is set forth and it is believed that the above-described technical solutions are well known to those skilled in the art. Summary of the invention

 An object of the embodiments of the present invention is to provide an adaptive multi-stream beamforming method and a base station, which extend the existing dual-stream beamforming algorithm to a multi-stream beamforming algorithm, and determine the number of beamforming flows based on the channel capacity. , adaptive transmission of beamforming to improve system flexibility.

 According to an aspect of an embodiment of the present invention, an adaptive multi-stream beamforming method is provided, wherein the method includes:

 The base station determines a channel matrix of the downlink according to the information sent by the UE;

 The base station calculates, according to the channel matrix, a channel capacity corresponding to the number of different beamforming flows;

 The base station selects the number of beamforming streams corresponding to the largest channel capacity for downlink beamforming according to the calculation result of the channel capacity.

 According to a second aspect of the present invention, a base station is provided, where the base station includes: a determining unit, configured to determine a channel matrix of a downlink according to information sent by a UE;

 a calculating unit, which calculates a channel capacity corresponding to the number of different beamforming flows according to the channel matrix determined by the determining unit;

 And a selecting unit, configured to perform downlink beamforming according to a calculation result of the channel capacity of the calculating unit, and selecting a beamforming flow number corresponding to a maximum channel capacity.

 According to a third aspect of the embodiments of the present invention, there is provided a computer readable program, wherein when the program is executed in a base station, the program causes a computer to perform the aforementioned adaptive multi-stream beamforming method in the base station .

 According to a fourth aspect of the embodiments of the present invention, there is provided a storage medium storing a computer readable program, wherein the computer readable program causes a computer to perform the aforementioned adaptive multistream beamforming method in a base station.

 The beneficial effects of the embodiments of the present invention are: by extending the existing dual-stream beamforming algorithm to the multi-stream beamforming algorithm, and determining the number of beamforming flows based on the channel capacity, thereby realizing adaptive transmission of beamforming, and improving System flexibility.

Specific embodiments of the present invention are disclosed in detail with reference to the following description and the accompanying drawings. It should be understood that the embodiments of the invention are not limited in scope. In The embodiments of the present invention include many variations, modifications, and equivalents within the scope of the spirit and scope of the appended claims. Features described and/or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, in combination with, or in place of, features in other embodiments. .

 It should be emphasized that the term "comprising" or "comprising" is used to mean the presence of a feature, component, step or component, but does not exclude the presence or addition of one or more other features, components, steps or components. DRAWINGS

 Many aspects of the invention can be better understood with reference to the following drawings. The components in the figures are not drawn to scale, but only to illustrate the principles of the invention. To facilitate the illustration and description of some parts of the invention, the corresponding parts in the drawings may be enlarged or reduced. The elements and features described in one of the figures or one embodiment of the invention may be combined with elements and features illustrated in one or more other figures or embodiments. In the accompanying drawings, like reference numerals refer to the In the drawing:

 1 is a flowchart of an adaptive multi-stream beamforming method according to an embodiment of the present invention;

 2 is a flow chart of a method for calculating channel capacity corresponding to different beamforming flows in the embodiment shown in FIG. 1. FIG. 3 is a method for determining channel capacity of each beamforming stream in the embodiment shown in FIG. 2. FIG. 4 is a schematic structural diagram of a base station according to an embodiment of the present invention. detailed description

 The foregoing and other features of the embodiments of the invention will be apparent from the These embodiments are merely exemplary and are not limiting of the invention. In order to enable the person skilled in the art to easily understand the principles and embodiments of the present invention, the embodiment of the present invention is described by taking a single-user adaptive multi-stream beamforming method in the LET-A system as an example, but it can be understood that Embodiments of the invention are not limited to the above described systems and are applicable to other systems involving multi-stream beamforming.

 Example 1

 FIG. 1 is a flowchart of an adaptive multi-stream beamforming method according to an embodiment of the present invention. Referring to FIG. 1, the method includes:

Step 101: The base station determines a channel matrix of the downlink according to the information sent by the UE. Step 102: The base station calculates a channel capacity corresponding to the number of different beamforming flows according to the channel matrix. Step 103: The base station selects a beamforming stream with a maximum channel capacity to perform downlink beamforming according to the calculation result of the channel capacity.

 In this embodiment, after the base station determines the number of beamforming flows, the number of beamforming flows can be notified to the UE, so that the UE performs corresponding data transceiving processing according to the number of beamforming flows. There are many methods for the base station to notify the UE of the determined number of beamforming flows, for example, by sending a new message to the UE to indicate the determined number of beamforming flows, or by using the existing message sent to the UE. The reserved field in the field indicates the determined number of beamforming flows, or by other means. The above is only an example, and the embodiment is not limited thereto.

 In step 101, the base station may calculate the channel matrix of the downlink according to the uplink and downlink reciprocity of the LTE-A TDD system according to the channel impulse response of the uplink user. For example, the base station determines the channel state information of the uplink according to the Sounding Reference Signal (SRS) reported by the user, and determines the channel state information of the downlink according to the uplink and downlink reciprocity, thereby determining the downlink. Channel matrix. In step 101, the base station may also determine the channel matrix of the downlink according to other information reported by the user. For example, the user can directly report the channel state information of the downlink to the base station, whereby the base station can also determine the channel matrix of the downlink.

In one embodiment, it is assumed that the base station (eNodeB) side employs N antennas, and the UE (UE) side employs M antennas. For the uplink, the UE side uses M antennas to transmit signals in turn, and the eNodeB side uses N antennas to simultaneously receive. Belle, the base station can use the combined channel estimation processing method to combine the channel estimates obtained at consecutive M 'times to obtain the channel matrix: H = [/3⁄4 h ₂ ... h _M ]. Among them, M ' may be the same as M or different.

 In step 102, the base station can calculate the channel capacity corresponding to the number of different beamforming flows by using the method shown in FIG. 2. Referring to FIG. 2, the method includes:

 Step 201: The base station determines a number of beamforming flows that need to calculate a channel capacity.

The base station may determine, according to the channel matrix, a number of streamforms that need to calculate a channel capacity. For example, the base station may use the smaller of the number of antennas on the base station side and the number of antennas on the user side as the maximum number of beamforming flows that need to calculate the channel capacity, and determine the number of beamforming flows that need to calculate the channel capacity. Flow to the maximum beam shaping stream number. Still taking the foregoing as an example, if N < M, it is determined that the number of beamforming flows that need to calculate beamforming traffic is 1 to N; if N > M, it is determined that the number of beamforming flows that need to calculate beamforming traffic is 1~M. For example, for a 2 X 4 matrix, the number of beamforming flows that need to calculate the channel capacity is single stream and dual stream. For a 4 X 4 matrix, the number of beamforming streams that need to calculate channel capacity is single stream, dual stream, third stream, and quad stream. , and so on.

Step 202: The base station decomposes the channel matrix by using a SVD (Sigular Value Decomposition) decomposition method, and uses a column vector of the decomposed right singular matrix as a beamforming weight vector; wherein the SVD decomposition method is used to step 101. The determined channel matrix is decomposed and can be expressed as follows: H = U∑V ^H .

Where H is the channel matrix determined in step 101, ! ! Two ^, ^...! ! ^ is a left singular matrix, V = [v _p > _VAi ] is a right singular matrix, ∑ is a diagonal matrix, diagonal elements, ^, ... ^? ^ is a singular value. In this embodiment, the column vector of the right singular matrix is used as the beamforming weight vector.

 Step 203: The base station calculates, according to the beamforming weight vector and the weighting processing vector of the receiving end, a channel capacity corresponding to each beamforming stream number determined.

 The base station may first establish a receiving signal model of the receiving end, and calculate a channel capacity corresponding to each determined beamforming stream number based on the received signal model.

 Wherein, the received signal model can be based on a minimum mean square error MMSE (Min Mean Square

Error) Receive criteria established. In one embodiment of the received signal model, it is assumed that the signal received by the UE side is:

 y = HFx + n.

 Where H is a channel matrix, for example, may be an M x N channel matrix, F is a beamforming weight vector, X is a transmission signal, and n is noise.

In the received signal model, it is assumed that the noise average power at the receiving end is N _Q and that the transmitted power is defined as E(x ^H x) = P _T , and the power is evenly distributed among the plurality of data streams.

 In step 203, the base station calculates the channel capacity of each of the beamforming streams determined in step 201, which can be implemented by the method shown in FIG. 3. Referring to FIG. 3, the method includes:

 Step 301: The base station determines, according to a beamforming weighting vector corresponding to the current beamforming stream number, an equivalent channel matrix corresponding to the current beamforming stream number;

 Wherein, according to the beamforming weight vector F, it may be determined that the equivalent channel matrix of the channel matrix determined in step 101 is:

Fi = HF. According to step 202, H can be decomposed into [/∑V ^H , and the equivalent channel matrix can be obtained by substituting U, ∑ and F corresponding to the current beamforming stream into the above equation.

 Step 302: The base station calculates, according to the equivalent channel matrix, a weighting processing vector of a receiving end of each data stream corresponding to the current beamforming stream number;

 Wherein, assuming that the receiving end (the UE side) receives based on Minimum Mean Square Error (MMSE), the weighting processing vector of the receiving end can be expressed as:

Wherein, it is a channel matrix equivalent to a beamforming, and in this embodiment, it may be an equivalent channel matrix determined as described above. N. It is the average power of the noise at the receiving end determined according to the received signal model, which is the transmitted signal power determined according to the received signal model, and I = F"F is the identity matrix.

 Step 303: The base station calculates, according to the equivalent channel matrix and the weighting processing vector of the receiving end, and the signal to noise ratio of the receiving end, a signal to interference plus noise ratio (SINR) of each data stream corresponding to the current beamforming stream number. Signal to Interference plus Noise Ratio );

 Wherein, if the single stream beamforming channel capacity is to be calculated, the SINR of one channel of data stream can be calculated; if the dual stream beamforming channel capacity is to be calculated, the SINR of the two channels of data is calculated; if the three stream beamforming channel is to be calculated Capacity, then calculate the SINR of the three-way data stream, and so on. Wherein, which number of data streams are to be selected to calculate the SINR may be determined according to the diagonal elements in the diagonal matrix after decomposing the channel matrix determined in step 101, according to the order of the diagonal elements from large to small. Select the corresponding data stream.

 For example, when calculating the SINR of the data stream, the right singular column vector corresponding to the diagonal element having the largest median value of the diagonal matrix is selected as the beamforming weight vector, and the SINR of the data stream corresponding to the beamforming weight vector is calculated; When calculating the SINR of the two data streams, two right singular column vectors corresponding to the two diagonal elements of the median of the diagonal array are selected as the beamforming weight vector, and each data corresponding to the beamforming weight vector is calculated. The SINR of the stream; and so on.

 Step 304: The base station calculates, according to the SINR of each data stream corresponding to the current beamforming flow, the channel capacity of the channel corresponding to each data stream.

 Wherein, the SINR corresponding to each data stream is obtained, and the channel capacity of the channel corresponding to the data stream can be calculated accordingly. The specific calculation method can be implemented by existing means, and details are not described herein again.

Step 305: The base station calculates a total channel capacity corresponding to the current beamforming flow number according to a channel capacity of a channel corresponding to each data stream. The total channel capacity of the current beamforming stream number is obtained by using a channel capacity phase port of a channel of each data stream corresponding to the current beam shaping stream number.

 In the present embodiment, for single-stream beamforming, since there is only one data stream, interference between data streams is not generated, and MMSE filtering weighted interference can be ignored. For dual-flow beamforming, or three-stream beamforming, or beamforming of more beamforming streams, because there are multiple data streams, interference will occur between the data streams, and the weighted processing vector of the receiving end is needed. Take it into consideration. Based on the established received signal model, the received signal on the user side can be expressed as the product of the weighted processing vector of the receiving end and the received signal.

 In order to make step 203, that is, the method shown in FIG. 3, more clear and easy to understand, the following is a single stream beamforming channel capacity calculation process, a dual stream beamforming channel capacity calculation process, a three-stream beamforming channel capacity calculation process, and four The flow beamforming channel capacity calculation process is taken as an example, and the method of this embodiment is described in detail.

Among them, based on the established received signal model, the single-flow beamforming channel capacity calculation process is as follows: Let the transmission signal c = shape vector = _νι , then the equivalent channel matrix is:

 H = HF:! ! ^ ^ , .

Where ^ is the first column of the left singular matrix and is the largest singular value, let & = _{CTl l} , then:

 y = HFx + n = + n.

The received signal SINR is:

 Therefore, the single-stream beamforming channel capacity is:

C = log ₂ (l + S fiber).

 The calculation process of the dual-flow beamforming channel capacity is as follows based on the established received signal model: Let the transmit signal c = the shaped vector = [^, ], then the equivalent channel matrix is:

H = HF = U∑V ^H F = a ₂ u ₂ ] o

Among them, is the largest singular value, σ ₂ is the second largest singular value, is the first column of the left singular matrix, and 1 ₂ is the second column of the left singular matrix.

Let [σ^ σ ₂ η ₂ ] = ^ g ₂ ],

贝'J: y = HFx + n = + g ₂ x ₂ + n.

In this embodiment, the MMSE detection algorithm is used to eliminate inter-stream interference. For the data stream, the MMSE filter weighting processing vectors at the receiving end are: corpse

^{_{io 2 = (g & H +}} g 2 g 2 H + ^ iy l g of the MMSE receiver signals are:

3⁄4 = = ro _{1 1} jc ₁ + ω ₁ (g ₂ x ₂ + n);

 Useful signal interference signal and noise

x ₂ = co ₂ y = (o ₂ g ₂ x ₂ + ω ₂ (g _t + n).

 Useful signal interference signal and noise

=log₂(l + S纖 。 For the first

=log ₂ (l + S fiber.

 For the second data stream, the received SINR is:

 s position

 The channel traversal capacity of the second data stream is:

C ₂ = log ₂ (l + face ₂ ).

 Therefore, the total system capacity when dual-stream beamforming is:

C = C ₁ + C ₂ = log ₂ [(l + SINR, ) (1 + SINR ₂ )].

Among them, based on the established received signal model, the three-stream beamforming channel capacity calculation process is as follows: Let the transmit signal x = [ ^, , ], shape vector? = [ ,^,^], then the equivalent channel matrix is: ίί = HF = U∑V ^H F = [σ^ σ ₂ υ ₂ σ ₃ ιι ₃ ].

Among them, is the largest singular value, σ ₂ is the second largest singular value, σ ₃ is the third largest singular value, ^ is the first column of the left singular matrix, " ₂ is the second column of the left singular matrix, " ₃ is The third column of the left singular matrix.

Let [ i^ cr ₂ u ₂ cr ₃ u ₃ ] = [g ₁ g ₂ g ₃ ], then:

y = HFx + n = g ₁ Jc ₁ + g _{2 3⁄4} + g _{3 3⁄4} + n.

For the data stream, x ₂ and the MMSE filter weighting vector of the receiving end are:

ω ₁ =( _§1§1 ^ίί _+§2§2 ^ίί _+§ 3 _§ 3 ^ίί + ^3⁄4 )- ¹ _§1 ; ω ₂ =(g ₁ ^H _+g2 g ₂ ^H _+g3 g ₃ ^H +^iy ^l g ₂ ; ω ₃ =^ ₊ ^ ₊ ^ + Ι)- 〖g ₃ So the MMSE receiving signals are:

Χι =(» ₁ y = oi ₁ g _l x _l +oi ₁ (g ₂ x ₂ +g ₃ x ₃ +n);

 Useful signal interference signal and noise

x ₂ =to ₂ y = ro _{2 2} jc ₂ + ro ₂ ( ₁ jc ₁ +g _{3 3⁄4} +n);

 Useful signal interference signal and noise

_3⁄4 = to ₃ y = co ₃ g ₃ + ω ₃ (giXi + ₂ 3⁄4 + ⁿ ).

 Useful signal interference signal and noise

For the first

Similarly, the SINRs received by the second data stream and the third data stream are:

SINR ₂ = g ₂ ^H (g _lgl ^H + g ₃ g ₃ ^H +^iy ^l g ₂ ; difficult ₃ = § ₃ +^ + 1) . Therefore, when the beamforming of three data streams is performed, the traversing channel capacity is:

C = C ₁ + C ₂ + C ₃ = log ₂ [(1 + SINR, ) (1 + SINR ₂ ) (1 + SINR ₃ )].

And so on, based on the established received signal model, traversing the channel capacity when beamforming four data streams

C = C _y + C ₂ + C ₃ + C = log ₂ [(1 + SINR, )(1 + SINR ₂ )(1 + SINR ₃ )(1 + SINR ₄ )]

Its towel _:

SINR, gl (g ₂ §2 + g ₃ g ₃ + g ₄ g ₄ )- p

AN SINR 2 ^— §2 + g ₃ g ₃ + g ₄ g ₄ p

AN SINR g ₃ " ( gig + g ₂ g ₂ + g ₄ g ₄ pg ₃ ;

AN SINR _A §4 + g ₂ g ₂ " +g ₃ g ₃ g ₄ .

[gi"- g ₄ ]-[o- ₁ u ₁ --- c ₄ u ₄ ].

By the method described in the above embodiment, the letter corresponding to the different beamforming flows in step 102 can be obtained. The number is subjected to downlink beamforming.

 Wherein, if it is determined that the number of beamforming flows corresponding to the maximum channel capacity is n, then the n-stream beamforming is performed on the downlink, and the shaping formula can be:

 Where ^^(0 represents the transmitted signal of antenna port p, v„ is the nth right singular vector, which is the data after beamforming.

 An embodiment of the present invention provides an adaptive multi-stream beamforming method applied in a TDD LTE-Advanced system. The method uses channel capacity as a decision mechanism, considers channel conditions, and adaptively selects a beamforming stream number, and increases The flexibility of the system increases the overall performance of the TDD LTE-Advanced system.

 An embodiment of the present invention further provides a base station, as described in Embodiment 2 below. For the implementation of the base station, refer to the implementation of the method in Embodiment 1, and the description of the method is not repeated here.

 Example 2

 FIG. 4 is a schematic structural diagram of a base station according to an embodiment of the present invention. As shown in FIG. 4, the base station includes: a determining unit 41, configured to determine a channel matrix of the downlink according to information sent by the UE; and a calculating unit 42 that calculates different beams according to the channel matrix determined by the determining unit 41. The channel capacity corresponding to the number of shaped streams;

 The selecting unit 43 performs downlink beamforming according to the calculation result of the channel capacity by the calculating unit 42 and selecting the number of beamforming streams corresponding to the channel capacity.

 In an embodiment, the base station further includes:

 The notifying unit 44 is configured to notify the user of the number of beamforming flows selected by the selecting unit 43. In one embodiment, the calculating unit 42 includes:

 a determining module 421, configured to determine a number of beamforming flows that need to calculate a channel capacity;

 The decomposition module 422 is configured to decompose the channel matrix determined by the determining unit 41 by using a singular value decomposition SVD decomposition method, and use the column vector of the decomposed right singular matrix as a beamforming weight vector;

a calculation module 423, configured to calculate, according to the beamforming weight vector obtained by the decomposition module 422 and the weighting processing vector of the receiving end, the channel corresponding to each beamforming stream determined by the determining module 421 In one embodiment, the determining module 421 includes:

 a comparison sub-module 4211, configured to compare the number of antennas on the base station side with the number of antennas on the user side; and determine a sub-module 4212, configured to compare the number of antennas according to the comparison result of the comparison sub-module 4211 The smaller one is the maximum number of beamforming flows that need to calculate the channel capacity, and the number of beamforming flows that need to calculate the channel capacity is determined to be a single stream to the maximum beamforming stream number.

 In one embodiment, the decomposition module 422 is specifically configured to decompose the channel matrix determined by the determining unit according to the following formula:

H = U∑V ^H .

 Where H is the channel matrix, U is the left singular matrix, V is the right singular matrix, and ∑ is the diagonal matrix.

 In an embodiment, the calculating module 423 is specifically configured to: determine, according to a beamforming weighting vector corresponding to the current beamforming stream number, an equivalent channel matrix corresponding to the current beamforming stream number; according to the equivalent channel a matrix, calculating a weighting processing vector of a receiving end of each data stream corresponding to the current beamforming stream number; calculating a corresponding current beam assignment according to the equivalent channel matrix and the weighting processing vector of the receiving end, and the signal to noise ratio of the receiving end a signal-to-interference plus noise ratio SINR of each data stream of the number of streams; calculating a channel capacity of a channel corresponding to each of the data streams according to the SINR of each data stream corresponding to the current beamforming stream; Corresponding to the channel capacity of the channel of each of the data streams, the total channel capacity corresponding to the current beamforming stream number is calculated.

 The calculation module 423 is specifically configured to calculate a weighting processing vector of the receiving end of each data stream corresponding to the current beamforming stream according to the following formula:

ω two ^H H (HH Η,. where 11 is the equivalent beamforming channel matrix, N. is the noise power, a transmission signal power, I = F "F is an identity matrix.

 An embodiment of the present invention provides a base station used in a TDD LTE-Advanced system, where the base station adopts an adaptive multi-stream beamforming method, and uses channel capacity as a decision mechanism to consider channel conditions and adaptively select beamforming flows. Increases the flexibility of the system, which in turn improves the overall performance of the TDD LTE-Advanced system.

 Embodiments of the present invention also provide a computer readable program, wherein when the program is executed in a base station, the program causes a computer to perform the adaptive multi-stream beamforming method of Embodiment 1 in the base station.

An embodiment of the present invention further provides a storage medium storing a computer readable program, wherein the computer The reading program causes the computer to perform the adaptive multi-stream beamforming method described in Embodiment 1 in the base station.

 The above apparatus and method of the present invention may be implemented by hardware, or may be implemented by hardware in combination with software. The present invention relates to a computer readable program that, when executed by a logic component, enables the logic component to implement the apparatus or components described above, or to cause the logic component to implement the various methods described above Or steps. Logic components such as field programmable logic components, microprocessors, processors used in computers, and the like. The present invention also relates to a storage medium for storing the above program, such as a hard disk, a magnetic disk, an optical disk, a DVD, a flash memory, or the like.

 The present invention has been described in connection with the specific embodiments thereof, and it should be understood by those skilled in the art that these descriptions are not intended to limit the scope of the invention. A person skilled in the art can make various modifications and changes to the invention in accordance with the spirit and the principles of the invention, which are also within the scope of the invention.

Claims

Claim  An adaptive multi-stream beamforming method, where the method comprises:  The base station determines a channel matrix of the downlink according to the information sent by the UE;  The base station calculates, according to the channel matrix, a channel capacity corresponding to the number of different beamforming flows;  The base station selects the number of beamforming streams corresponding to the largest channel capacity for downlink beamforming according to the calculation result of the channel capacity.  The method according to claim 1, wherein after the downlink beamforming is performed by selecting the number of beamforming streams corresponding to the maximum channel capacity, the method further includes:  The base station notifies the user of the selected number of beamforming flows.  The method according to claim 1, wherein the base station calculates the channel capacity corresponding to the number of different beamforming flows according to the channel matrix, including:  The base station determines the number of beamforming flows that need to calculate the channel capacity;  The base station decomposes the channel matrix by using a singular value decomposition SVD decomposition method, and uses a column vector of the decomposed right singular matrix as a beamforming weight vector;  The base station calculates a channel capacity corresponding to each determined beamforming stream according to the beamforming weight vector and the weighting processing vector at the receiving end.  4. The method according to claim 3, wherein the base station determines the number of beamforming flows that need to calculate the channel capacity, including:  The base station uses the smaller of the number of antennas on the base station side and the number of antennas on the user side as the maximum number of beamforming flows that need to calculate the channel capacity;  The number of beamforming flows that need to calculate the channel capacity is determined to be a single stream to the maximum beam shaping stream number.  5. The method according to claim 3, wherein the base station decomposes the channel matrix by using a singular value decomposition SVD decomposition method, which is decomposed according to the following formula: H = U∑V ^H  Where H is the channel matrix, U is a left singular matrix, V is a right singular matrix, and ∑ is a diagonal matrix. The method according to claim 3, wherein the base station calculates a channel capacity corresponding to each determined beamforming stream according to the beamforming weight vector and the weighting processing vector of the receiving end, including: a beamforming weighting vector corresponding to the number of beamforming flows, determining an equivalent channel matrix corresponding to the current beamforming stream number; The base station calculates, according to the equivalent channel matrix, a weighting processing vector of the receiving end of each data stream corresponding to the current beamforming stream number;  The base station calculates, according to the equivalent channel matrix and the weighting processing vector of the receiving end, and the signal to noise ratio of the receiving end, a signal to interference plus noise ratio (SINR) of each data stream corresponding to the current beamforming stream number; Calculating a SINR corresponding to each data stream of the current beamforming stream, and calculating a channel capacity of a channel corresponding to each of the data streams;  The base station calculates, based on the channel capacity of the channel corresponding to each of the data streams, a total channel capacity corresponding to the current beamforming stream number.  7. The method according to claim 6, wherein the base station calculates a weighting processing vector of the receiving end of each data stream corresponding to the current beamforming stream number, which is calculated according to the following formula: H ^H (HH ^Η +^ΙΤ ^ι ; where H is the equivalent channel matrix, N is the noise power, is the transmitted signal power, and I = F"F is the identity matrix.  8. A base station, where the base station includes:  a determining unit, configured to determine a channel matrix of the downlink according to information sent by the UE;  a calculating unit, which calculates a channel capacity corresponding to the number of different beamforming flows according to the channel matrix determined by the determining unit;  And a selecting unit, configured to perform downlink beamforming according to a calculation result of the channel capacity of the calculating unit, and selecting a beamforming flow number corresponding to a maximum channel capacity.  The base station according to claim 8, wherein the base station further comprises:  a notifying unit, configured to notify the user end of the number of beamforming flows selected by the selecting unit. The base station according to claim 8, wherein the calculating unit comprises:  a determining module for determining a number of beamforming flows that need to calculate a channel capacity;  a decomposition module, configured to decompose a channel matrix determined by the determining unit by using a singular value decomposition SVD decomposition method, and using a column vector of the decomposed right singular matrix as a beamforming weight vector;  And a calculation module, configured to calculate, according to the beamforming weight vector obtained by the decomposition of the decomposition module, and the weighting processing vector of the receiving end, a channel capacity corresponding to each beamforming stream determined by the determining module.  The base station according to claim 10, wherein the determining module comprises: a comparison submodule, configured to compare the number of antennas on the base station side with the number of antennas on the user side; Determining a sub-module, configured to determine, according to a comparison result of the comparison sub-module, a smaller one of the numbers as a maximum beamforming flow rate that needs to calculate a channel capacity, and determine a beamforming flow that needs to calculate a channel capacity. The number is a single stream to the maximum beam shaping stream number.  The base station according to claim 10, wherein the decomposition module is specifically configured to decompose the channel matrix determined by the determining unit according to the following formula: H = U∑V ^H  Where H is the channel matrix, U is the left singular matrix, V is the right singular matrix, and ∑ is the diagonal matrix.  The base station according to claim 10, wherein the calculation module is specifically configured to:  Determining an equivalent channel matrix corresponding to the current beamforming stream number according to a beamforming weighting vector corresponding to the current beamforming stream number;  Calculating, according to the equivalent channel matrix, a weighting processing vector of a receiving end of each data stream corresponding to the current beamforming stream number;  And calculating, according to the equivalent channel matrix and the weighting processing vector of the receiving end, and the signal to noise ratio of the receiving end, a signal to interference plus noise ratio SINR of each data stream corresponding to the current beamforming stream number;  Calculating a channel capacity of a channel corresponding to each of the data streams according to the SINR of each data stream corresponding to the current beamforming stream number;  The total channel capacity corresponding to the current beamforming stream is calculated based on the channel capacity of the channel corresponding to each of the data streams.  The base station according to claim 13, wherein the calculation module is specifically configured to calculate a weighting processing vector of a receiving end of each data stream corresponding to the current beamforming stream according to the following formula: H ^H (HH ^Η +^ΙΤ ^ι ; where is the equivalent channel matrix, N. is the noise power, is the transmitted signal power, and I = F"F is the identity matrix.  15. A computer readable program, wherein the program causes a computer to perform an adaptive multi-stream beam according to any one of claims 1 to 7 in the base station when the program is executed in a base station Forming method.  A storage medium storing a computer readable program, wherein the computer readable program causes a computer to perform the adaptive multistream beamforming method of any one of claims 1 to 7 in a base station.