CN102013907B - Channel information feedback method of beam shaping system with Mt*2MIMO (Multiple Input Multiple Output) characteristic - Google Patents

Abstract

The invention relates to a channel information feedback method of a beam shaping system with a Mt*2MIMO (Multiple Input Multiple Output) characteristic, which only needs to feed back characteristic values lambda 1and lambda2 and a characteristic vector v1. The method particularly comprises the steps of: estimating a channel matrix H of a descending wireless channel by a user equipment terminal MS (Memory System); carrying out SVD (singular value decomposition) on the H by the user equipment terminal MS to obtain the lambda 1, the lambda 2 and the v1; quantizing and feeding back the lambda 1, the lambda2 and the v 1 by the user equipment terminal MS; solving a v 2 through v2=eigvec2[HHH] by using a formula HHH=lambda 1v1v1H+lambda2(E-v1v1H) by a base station BS on the basis of the feedback information quantity of the user equipment terminal MS; carrying out beam forming by adopting V=[v1H, v2H]H by the base station BS; and completing the channel information feedback method of the beam shaping system with the Mt*2MIMO characteristic. The invention ensures that the MIMO beam shaping system obtains greatest system capacity and space diversity gain and simultaneously reduces channel feedback information capacity, improves the transfer effectiveness of the MIMO beam shaping system, and enhances the practicability of the MIMO beam shaping system.

Description

A kind of M t* 2MIMO Eigen-beamforming system channel information feedback method

Technical field

The present invention relates to the wireless MAN access field, particularly a kind of M _t* 2MIMO Eigen-beamforming system channel information feedback method.

Background technology

The MIMO technology will become the mainstream technology in 4G communication, in order to obtain the diversity gain of mimo system fully, worked out in recent years various treatment technologies when empty, wherein, MIMO beam forming technology is because obtaining maximum power system capacity and various diversity gain receives much concern.Use the system of MIMO beam forming technology to be MIMO beam forming system.MIMO beam forming system postulation transmitting terminal and receiving terminal are all known channel condition information completely, utilize transmitting terminal beam forming (Transmit Beamforming) and receiving terminal high specific folding (Receiver Combining) to increase power system capacity and obtain space diversity gain, thereby improve reliability and the validity of transfer of data.

Generally, due to the restriction of antenna distance, the antenna number that handheld terminal is equipped with is 2, and this kind of transmission system is designated as to M _t* 2MIMO beam forming system.Wherein, base station end configuration M _tthe root transmitting antenna, 2 reception antennas of terminal configuration.

Existing M _t* 2MIMO Eigen-beamforming system reference model is comprised of base station BS and two logic entities of subscriber equipment terminal MS.The mathematical description of System Working Principle is so:

y＝U ^HHVΛx+N (1)

In formula (1), x=[x ₁, x ₂] ^tfor transmitted signal;

for the power division matrix; H=U Λ V ^hfor channel matrix; Y=[y ₁, y ₂] ^tfor receiving signal.

By formula (1), can be found out, transmitting terminal power division and Eigen-beamforming all need to know channel matrix Λ and V, in system, usually by the receiving terminal feedback channel matrixes, are obtained, and therefore, work as especially M _twhen larger, amount of channel feedback will be larger, too much feedback of channel information can take limited transfer resource, thereby reduce the validity of mimo system, even may balance out the gain that the beam forming technology itself is brought, therefore be necessary to reduce the feedback quantity of channel information.

For convenience of understanding, below list the bilingual of some terms that occur in the present invention:

MS:Mobile Station, travelling carriage

BS:Base Station, base station

MIMO:Multi-input Multi-output, multiple-input, multiple-output

Summary of the invention

The object of the invention is to, in the situation that the normal operation of assurance system, the feedback information volume of reduction channel.

For achieving the above object, the present invention proposes a kind of M _t* 2MIMO Eigen-beamforming system channel information feedback method.

The method only need to be fed back two eigenvalue λ ₁, λ ₂an and characteristic vector v ₁; Described method specifically comprises the following steps:

Step 1): the subscriber equipment terminal MS is estimated the channel matrix H of downlink wireless channel;

Step 2): the subscriber equipment terminal MS is carried out the SVD decomposition to H, obtains λ ₁, λ ₂, v ₁;

Step 3): the subscriber equipment terminal MS is to λ ₁, λ ₂, v ₁quantized and fed back;

Step 4): base station BS is according to subscriber equipment terminal MS feedback information volume, and utilizes formula H ^hh=λ ₁v ₁v ₁ ^h+ λ ₂(E-v ₁v ₁ ^h), by v ₂=eigvec ₂[H ^hh] try to achieve v ₂;

Step 5): base station BS adopts V=[v ₁ ^h, v ₂ ^h] ^hcarry out beam forming;

So far, completed M _t* 2MIMO Eigen-beamforming system channel information feedback.

The formula of the channel matrix H of described downlink wireless channel is: H=U Λ V ^h.

Described λ ₁and λ ₂for H ^hthe characteristic value of H.

Described v ₁corresponding to singular value

right singular vector.

In the formula of the channel matrix H of described downlink wireless channel, Λ is the power division matrix,

The invention has the advantages that, when making MIMO beam forming system obtain maximum power system capacity and space diversity gain, the method reduces the feedback information volume of channel, promote the transmission availability of MIMO beam forming system, strengthened the practicality of MIMO beam forming system.In addition, each job step of the present invention all can realize by general-purpose calculating appts, also can realize with the executable program code of calculation element, thereby the present invention does not limit with any specific hardware and software is combined.

The accompanying drawing explanation

The M that Fig. 1 is traditional _t* 2MIMO Eigen-beamforming system diagram;

A kind of M that Fig. 2 the present invention proposes _t* 2MIMO Eigen-beamforming system channel information feedback method flow chart.

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in further detail, should be appreciated that preferred embodiment described herein, only for description and interpretation the present invention, is not intended to limit the present invention.

Traditional M _t* 2MIMO Eigen-beamforming system diagram, as shown in Figure 1.This system is comprised of base station BS and two logic entities of subscriber equipment terminal MS.At the base station end, the symbol that the input data produce through coded modulation is through string the conversion of speed 2, and every two symbols form a symbol to { x ₁, x ₂.These two symbols, after power division and Eigen-beamforming, send through channel.At receiving terminal, after feature weight merges, recovered.

Based on a kind of M _t* 2MIMO Eigen-beamforming system channel information feedback method flow chart, as shown in Figure 2.First define following variable:

H: wireless channel matrix;

λ _i(i=1,2): channel matrix H ^hthe characteristic value of H;

V ₁: corresponding to singular value

right singular vector;

As shown in Figure 2, a kind of M that the present invention proposes _t* 2MIMO Eigen-beamforming system channel information feedback method comprises the following steps:

Step S201, MS estimates the channel H of down wireless link;

Step S202, MS carries out the SVD decomposition to H, obtains λ ₁, λ ₂, v ₁;

Step S203, MS is to λ ₁, λ ₂, v ₁quantized and fed back;

Step S204, BS is according to the MS feedback information volume, and utilizes formula H ^hh=λ ₁v ₁v ₁ ^h+ λ ₂(E-v ₁v ₁ ^h), v ₂=eigvec ₂[H ^hh] try to achieve v ₂;

Step S205, BS adopts V=[v ₁ ^h, v ₂ ^h] ^hcarry out beam forming.

It should be noted last that, above embodiment is only unrestricted in order to technical scheme of the present invention to be described.Although with reference to embodiment, the present invention is had been described in detail, those of ordinary skill in the art is to be understood that, technical scheme of the present invention is modified or is equal to replacement, do not break away from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of claim scope of the present invention.

Claims (4)

1. a M _t* 2MIMO Eigen-beamforming system channel information feedback method, the method only need to be fed back two eigenvalue λ ₁, λ ₂an and characteristic vector v ₁; Described method specifically comprises the following steps:

Step 1): the subscriber equipment terminal MS is estimated the channel matrix H of downlink wireless channel;

Step 2): the subscriber equipment terminal MS is carried out the SVD decomposition to H, obtains λ ₁, λ ₂, v ₁;

Step 3): the subscriber equipment terminal MS is to λ ₁, λ ₂, v ₁quantized and fed back;

Step 4): base station BS is according to the λ of subscriber equipment terminal MS feedback ₁, λ ₂, v ₁amount of information, utilize formula H ^hh=λ ₁ ^v ₁ ^v ₁ ^h+ λ ₂(E-v ₁v ₁ ^h), then by

try to achieve v ₂;

Step 5): base station BS adopts V=[v ₁ ^h, v ₂ ^h] ^hcarry out beam forming;

So far, completed M _t* 2MIMO Eigen-beamforming system channel information feedback; Described v ₁corresponding to singular value

₁right singular vector.

2. a kind of M according to claim 1 _t* 2MIMO Eigen-beamforming system channel information feedback method, is characterized in that, the formula of the channel matrix H of described downlink wireless channel is: H=U Λ V ^h.

3. a kind of M according to claim 1 _t* 2MIMO Eigen-beamforming system channel information feedback method, is characterized in that described λ ₁and λ ₂for H ^hthe characteristic value of H.

4. a kind of M according to claim 2 _t* 2MIMO Eigen-beamforming system channel information feedback method is characterized in that in the formula of the channel matrix H of described downlink wireless channel, Λ is the power division matrix, $\mathrm{\Λ}=\mathrm{diag}\{\sqrt{{\mathrm{\λ}}_1},\sqrt{{\mathrm{\λ}}_2}\}.$

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