CN103236879A - Coordinated beam forming method on basis of MRC-ZF (Maximum Ratio Combining to Zero Forcing) receiving vector estimation - Google Patents

Abstract

The invention provides a coordinated beam forming method on the basis of MRC-ZF (Maximum Ratio Combining to Zero Forcing) receiving vector estimation, which comprises the following steps that each collaborative base station estimates a receiving beam forming vector of a service user by using an MRC method according to known channel state information and a sending beam forming vector at previous moment; each collaborative base station carries out estimation on the basis of MRC-ZF again on a receiving beam forming vector of an interference user according to an estimated value of the receiving beam forming vector of the interference user and the channel state information; and each collaborative base station utilizes the estimated value of the receiving beam forming vector of the service user and the MRC-ZF receiving beam forming vector of the interference user to calculate a sending beam forming vector at current moment by using maximized SLNR (Signal to Leakage and Noise Ratio) as the principle. Compared with a conventional coordinated beam forming scheme on the basis of the maximized SLNR principle, the coordinated beam forming method on the basis of MRC-ZF receiving vector estimation is obviously improved on the aspect of performance, is low in system overhead and can be implemented at the position of each collaborative base station in a distributed manner.

Description

A kind of coordinates beam shaping method that receives the vector estimation based on MRC-ZF

Technical field

The invention belongs to cooperative multipoint transmission technical field in the wireless communication system, relate to a kind of based on the coordinates beam shaping method that reception wave beam forming vector is estimated.

Background technology

Combined Treatment Technology Need in the cooperative multipoint transmission is at the node data sharing and the channel condition information that participate in cooperation, though elevator system performance that can be maximum, but throughput and time delay to back haul link (Backhaul) have very high requirement, and sign synchronization there is strict requirement, be difficult to simultaneously under the existing network architecture and standard, realize, therefore realize comparatively difficulty.And the coordinates beam figuration is an important branch of cooperative multipoint transmission technology, a kind of half-way house is provided between Backhaul expense and systematic function, compare with Combined Treatment, the coordinates beam figuration only needs in base station shared channel state information, can coordinate and suppress the interference of minizone by methods such as transmitting-receiving beam optimization, power control, user's scheduling, therefore be easier under the existing network architecture, realize.When the number of users in the system is abundant, can improve systematic function significantly by this interference coordination mode.

It is existing that (Multiple Input Multiple Output, MIMO) system coordination wave beam forming scheme mainly is divided into egoistic scheme, sharp his scheme and egoistic-Li Ta half-way house for multiple-input and multiple-output.In egoistic scheme, base station transmitter is ignored the interference to other users, maximizes the utility function of self.This scheme signal to noise ratio (Signal-to-Noise Ratio, SNR) less, good performance arranged, but mis-behave during, serious interference big at SNR when noise is dominant.In sharp his scheme, base station transmitter minimizes the interference to other users.This scheme can effectively suppress inter-user interference, and is particularly bigger at SNR, namely disturbs when being dominant, and can access good performance.Yet this scheme efficient when middle low signal-to-noise ratio is lower.Egoistic-the Li Ta half-way house, maximization self utility function is compromised to other users' interference with minimizing, make systematic function reach optimum.There is document verified, if (Signal-to-Interference-and-Noise Ratio SINR) is criterion, and the transmission wave beam forming vector of designing is the linear combination of egoistic and sharp his two kinds of schemes with the maximization Signal to Interference plus Noise Ratio.Make an uproar than (Signal-to-Leakage-and-Noise Ratio SLNR) be criterion, and just this also need be egoistic and sharply do to compromise between him as can be seen from target function if leak with maximization letter.More than these schemes can be divided into the coordinates beam figuration scheme that consider to receive vector again and not consider to receive two kinds of the coordinates beam figuration schemes of vector, and the scheme that consider to receive vector does not consider more that on performance the scheme that receives vector has obvious lifting, but the expense of feedback overhead and information sharing is also a lot of greatly than the expense of not considering to receive the vector scheme.

Traditional transmission wave beam forming vector design based on the SLNR criterion can be located distributed realization in each base station, but because this method for designing is not considered to receive vector to Effect on Performance, causes systematic function relatively poor.If consider the reception vector of each base station, then need each cooperative base station to share whole channel condition informations, this can cause the X2 interface expense bigger again, implements difficulty relatively.

Summary of the invention

The object of the present invention is to provide a kind of coordinates beam shaping method that receives the vector estimation based on MRC-ZF.

For achieving the above object, the present invention has adopted following technical scheme.

This coordinates beam shaping method may further comprise the steps:

The first step, each cooperative base station is according to known channel condition information and last transmission wave beam forming vector constantly, estimate the received beam figuration vector of service-user with the mode of high specific merging, obtain high specific and merge received beam figuration vector estimated value, sharing separately then between cooperative base station, the high specific of service-user merges received beam figuration vector estimated value;

Second step, each cooperative base station merges received beam figuration vector estimated value and channel condition information according to the high specific of sharing the interference user that obtains, again the received beam figuration vector of interference user is carried out once obtaining high specific merging-ZF received beam figuration vector estimated value based on the estimation of high specific merging-ZF;

The 3rd step, each cooperative base station utilizes the high specific of service-user to merge the high specific merging-ZF received beam figuration vector estimated value of received beam figuration vector estimated value and interference user, make an uproar than being criterion with the leakage of maximization letter, calculate the transmission wave beam forming vector of current time.

Described coordinates beam shaping method specifically may further comprise the steps:

Consider a cooperative multicast system, this system contains M cooperative base station and M user, and i the service-user that the user is i base station, i=1, and 2 ..., M, the base station adopts the mode of coordinates beam figuration for user's service, uses PL _JiRepresent that i base station to j user's path loss, use H _JiRepresent that i base station to j user's channel matrix, suppose H _JiEach element separate and obey the multiple Gaussian Profile of zero-mean unit variance, the transmitting power of i base station is P _i, each user's reception noise is n _i, noise power is σ ², known its channel matrix to interior all users of cooperation set in each base station;

The first step: at transmitting terminal, the base station was at first estimated the received beam figuration vector of a last moment service-user based on the high specific merging criterion according to channel condition information and the transmission wave beam forming vector in a last moment, is got high specific and merge received beam figuration vector estimated value:

Represent last one constantly, high specific merging received beam figuration vector estimated value and the cooperative base station of service-user are shared in each base station, and the high specific that each base station, shared back all obtains all cooperative base station service-users merges received beam figuration vector estimated value ${\hat{v}}_i^{\mathrm{MRC}(n-1)},i=\mathrm{1,2},...,M;$

Second step: the high specific that share according to cooperative base station each base station merges the high specific merging-ZF received beam figuration vector estimated value that the known last moment channel condition information of received beam figuration vector estimated value and this base station calculates interference user, uses

The n-1 that expression base station i estimates is the high specific merging-ZF received beam figuration vector of user j constantly, j ≠ i, ${\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)}\left(i\right)$ For ${\hat{v}}_j^{\mathrm{MRC}(n-1)}{\hat{v}}_j^{\mathrm{MRC}(n-1)H}\text{+}{\mathrm{\β}}_{\mathrm{ji}}\frac{H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}{w}_i^{(n-1)H}{H}_{\mathrm{ji}}^{(n-1)H}}{{\left|\right|H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2}$ Eigenvalue of maximum characteristic of correspondence vector, wherein ${\mathrm{\β}}_{\mathrm{ji}}=-\frac{{\mathrm{PL}}_{\mathrm{ji}}{\left|\right|H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2}{\underset{k=1}{\overset{M}{\mathrm{\Σ}}}{\mathrm{PL}}_{\mathrm{ki}}{\left|\right|H_{\mathrm{ki}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2};$

The 3rd step: each base station utilizes the high specific of service-user to merge the high specific merging-ZF received beam figuration vector estimated value of received beam figuration vector estimated value and interference user, make an uproar than being the transmission wave beam forming vector that target is calculated this base station current time with the leakage of maximization letter, be shown below

Wherein, ${\mathrm{\Φ}}_i^{(n-1)}=\underset{j\≠i}{\mathrm{\Σ}}{P}_i{\mathrm{PL}}_{\mathrm{ji}}{H}_{\mathrm{ji}}^{(n-1)H}{\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)}\left(i\right){\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)H}\left(i\right)H_{\mathrm{ji}}^{(n-1)}+{\mathrm{\σ}}^2{I}_{N_t},$ Expression N _t* N _tThe dimension unit matrix;

The 4th step: after the 3rd step, the base station sends through the signal behind the wave beam forming to the user.

Beneficial effect of the present invention is:

The present invention obtains the estimated value to interference user received beam figuration vector by sharing a little information between each cooperative base station, sends the wave beam forming vector according to estimated value based on the criterion design that maximizes SLNR again.This scheme is compared traditional coordinates beam figuration scheme based on maximization SLNR criterion has remarkable lifting in performance, and overhead is less, and can be in each distributed realization in cooperative base station place.

Description of drawings

Fig. 1 is a kind of coordinates beam figuration system schematic, and among the figure, solid line is represented useful channel; Dotted line is represented interference channel; BS represents the base station; MS represents the user;

Fig. 2 is flow chart of the present invention;

Fig. 3 is user's average spectral efficiency (ase) contrast of different schemes under the static channel conditions;

Fig. 4 is user's average spectral efficiency (ase) contrast of different schemes under the slow Change channel condition.

Embodiment

The invention will be further described below in conjunction with accompanying drawing.

The main thought that receives the coordinates beam shaping method that vector estimates based on MRC-ZF that the present invention proposes is: the first step, each cooperative base station is according to known channel condition information and last transmission wave beam forming vector constantly, estimate the received beam figuration vector of service-user with the mode that high specific merges, and between cooperative base station, share; Second step, each cooperative base station merges the received beam figuration vector estimated value of (MRC) and the channel condition information of self grasping according to sharing the interference user that obtains based on high specific, again the received beam figuration vector of interference user is carried out once estimation based on high specific merging-ZF (MRC-ZF); The 3rd step, each cooperative base station is utilized service-user based on the received beam figuration vector of MRC estimation and the received beam figuration vector that interference user is estimated based on MRC-ZF, making an uproar than (SLNR) with the leakage of maximization letter is criterion, calculates the transmission vector of current time.

Specific embodiments is as follows:

The system of consideration shown in Fig. 1, this system contain M cooperative base station and M user, 1 user of each base station service, and i the service-user that the user is i base station, and i=1,2 ..., M, the base station adopts the mode of coordinates beam figuration to be user's service.Each base station is equipped with N _tThe root antenna, each user is equipped with N _rThe root antenna.PL _JiAnd H _JiRepresent that respectively i base station is to j user's path loss and channel matrix (N _r* N _tTie up), and hypothesis H _JiEach element separate and obey the multiple Gaussian Profile of zero-mean unit variance.The transmitting power of i base station is P _i, each user's reception noise is n _i, noise power is σ ²Suppose known its channel matrix to interior all users of cooperation set in each base station, i.e. i the known H in base station _Ji(j=1,2 ..., M).I user's reception signal y _iCan be expressed as:

$y_i=P_i{\mathrm{PL}}_{\mathrm{ii}}{v}_i^H{H}_{\mathrm{ii}}{w}_i{x}_i+\underset{j\≠i}{\mathrm{\Σ}}{P}_j{\mathrm{PL}}_{\mathrm{ij}}{v}_i^H{H}_{\mathrm{ij}}{w}_j{x}_j+n_i---\left(1\right)$

In the formula (1), x _iBe the transmission signal of i base station, w _i(N _t* 1 dimension, || w _i||=1) expression i base station transmission wave beam forming vector, v _i(N _r* 1 dimension, || v _i||=1) expression i user received beam figuration vector, subscript H represents conjugate transpose.Can obtain i user's reception Signal to Interference plus Noise Ratio by formula (1), as shown in Equation (2):

${\mathrm{SINR}}_i=\frac{P_i{\mathrm{PL}}_{\mathrm{ii}}{\left|v_i^H{H}_{\mathrm{ii}}{w}_i\right|}^2}{{\mathrm{\σ}}^2+\underset{j\≠i}{\mathrm{\Σ}}{P}_j{\mathrm{PL}}_{\mathrm{ij}}{\left|v_i^H{H}_{\mathrm{ij}}{w}_j\right|}^2}---\left(2\right)$

After having considered received beam figuration vector, the letter of i base station leaks makes an uproar than being expressed as:

${\mathrm{SLNR}}_i=\frac{P_i{\mathrm{PL}}_{\mathrm{ii}}{\left|v_i^H{H}_{\mathrm{ii}}{w}_i\right|}^2}{{\mathrm{\σ}}^2+\underset{j\≠i}{\mathrm{\Σ}}{P}_j{\mathrm{PL}}_{\mathrm{ij}}{\left|v_j^H{H}_{\mathrm{ji}}{w}_i\right|}^2}---\left(3\right)$

System's total frequency spectrum efficient and every user's average spectral efficiency (ase) are respectively shown in formula (4) and the formula (5):

$R_{\mathrm{total}}=\underset{i=1}{\overset{M}{\mathrm{\Σ}}}{\log }_2(1+{\mathrm{SINR}}_i)---\left(4\right)$

$R_k=\frac{1}{M}\underset{i=1}{\overset{M}{\mathrm{\Σ}}}{\log }_2(1+{\mathrm{SINR}}_i)---\left(5\right)$

The present invention proposes, and to receive the technological means of the coordinates beam figuration scheme that vector estimates based on MRC-ZF as follows:

Carry out following FOUR EASY STEPS at transmission end of base station:

The first step: at transmitting terminal, the base station at first according to last one constantly (n-1 constantly) channel condition information and send the wave beam forming vector calculates a last moment service-user based on the MRC criterion received beam figuration vector estimated value:

And between the base station, share, share the received beam figuration vector estimated value that each base station, back all obtains all cooperative base station service-users, that is: ${\hat{v}}_i^{\mathrm{MRC}(n-1)}(i=\mathrm{1,2},\·\·\·,M);$

Second step: the existing channel condition information of received beam figuration vector estimated value and this base station that calculates based on the MRC criterion that share according to cooperative base station each base station calculates high specific merging-ZF (MRC-ZF) the received beam figuration vector estimated value of interference user.For example, use

The n-1 that expression base station i estimates constantly user j (the MRC-ZF received beam figuration vector of j ≠ i) is got so ${\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)}\left(i\right)$ For ${\hat{v}}_j^{\mathrm{MRC}(n-1)}{\hat{v}}_j^{\mathrm{MRC}(n-1)H}\text{+}{\mathrm{\β}}_{\mathrm{ji}}\frac{H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}{w}_i^{(n-1)H}{H}_{\mathrm{ji}}^{(n-1)H}}{{\left|\right|H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2}$ Eigenvalue of maximum characteristic of correspondence vector, namely ${\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)}\left(i\right)=\max .\mathrm{eigvector}({\hat{v}}_j^{\mathrm{MRC}(n-1)}{\hat{v}}_j^{\mathrm{MRC}(n-1)H}+{\mathrm{\β}}_{\mathrm{ji}}\frac{H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}{w}_i^{(n-1)H}{H}_{\mathrm{ji}}^{(n-1)H}}{{\left|\right|H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2}),$ Wherein ${\mathrm{\β}}_{\mathrm{ji}}=-\frac{{\mathrm{PL}}_{\mathrm{ji}}{\left|\right|H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2}{\underset{k=1}{\overset{M}{\mathrm{\Σ}}}{\mathrm{PL}}_{\mathrm{ki}}{\left|\right|H_{\mathrm{ki}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2};$

The 3rd step: each base station utilizes the received beam figuration vector estimated value of calculating based on the MRC criterion of service-user and the MRC-ZF received beam figuration vector estimated value of interference user, and SLNR is the transmission wave beam forming vector that target is calculated this base station with maximization.Be shown below, the target function of i base station is:

$\underset{\left|\right|w_i^{\left(n\right)}\left|\right|=1}{\max }\mathrm{SL}{\mathrm{NR}}_i=\frac{P_i{\mathrm{PL}}_{\mathrm{ii}}{\left|{\hat{v}}_i^{\mathrm{MRC}(n-1)H}{H}_{\mathrm{ii}}^{(n-1)}{w}_i^{\left(n\right)}\right|}^2}{{\mathrm{\σ}}^2+\underset{j\≠i}{\mathrm{\Σ}}{P}_i{\mathrm{PL}}_{\mathrm{ji}}{\left|{\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)H}\left(i\right)H_{\mathrm{ji}}^{(n-1)}{w}_i^{\left(n\right)}\right|}^2}---\left(6\right)$

That is:

$w_i^{\left(n\right)}=\underset{\left|\right|w_i^{\left(n\right)}\left|\right|=1}{\arg \max }\frac{{\mathrm{PL}}_{\mathrm{ii}}{w}_i^{\left(n\right)H}{H}_{\mathrm{ii}}^{(n-1)H}{\hat{v}}_i^{\mathrm{MRC}(n-1)}{\hat{v}}_i^{\mathrm{MRC}(n-1)H}{H}_{\mathrm{ii}}^{(n-1)}{w}_i^{\left(n\right)}}{w_i^{\left(n\right)H}(\frac{{\mathrm{\σ}}^2}{P_i}{I_N}_t+\underset{j\≠i}{\mathrm{\Σ}}{\mathrm{PL}}_{\mathrm{ji}}{H}_{\mathrm{ji}}^{(n-1)H}{\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)}\left(i\right){\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)H}\left(i\right)H_{\mathrm{ji}}^{(n-1)})w_i^{\left(n\right)}}---\left(7\right)$

The solution of this optimization problem is

Wherein, ${\mathrm{\Φ}}_i^{(n-1)}=\underset{j\≠i}{\mathrm{\Σ}}{P}_i{\mathrm{PL}}_{\mathrm{ji}}{H}_{\mathrm{ji}}^{(n-1)H}{\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)}\left(i\right){\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)H}\left(i\right)H_{\mathrm{ji}}^{(n-1)}+{\mathrm{\σ}}^2{I}_{N_t},$

Expression N _t* N _tThe dimension unit matrix;

The 4th step: the base station sends through the signal behind the wave beam forming to the user.

Operation below receiving terminal is carried out:

The first step: the user adopts the least mean-square error that can make reception SINR maximum, and (Minimum Mean-Square Error, MMSE) criterion is calculated the received beam figuration vector of current time n, that is:

$v_i^{\left(n\right)}=\frac{{\left({\mathrm{\Ψ}}_i^{\left(n\right)}\right)}^{-1}{H}_{\mathrm{ii}}^{\left(n\right)}{w}_i^{\left(n\right)}}{\left|\right|{\left({\mathrm{\Ψ}}_i^{\left(n\right)}\right)}^{-1}{H}_{\mathrm{ii}}^{\left(n\right)}{w}_i^{\left(n\right)}\left|\right|}---\left(8\right)$

Wherein ${\mathrm{\Ψ}}_i^{\left(n\right)}=\underset{j\≠i}{\mathrm{\Σ}}{P}_j{\mathrm{PL}}_{\mathrm{ij}}{H}_{\mathrm{ij}}^{\left(n\right)}{w}_j^{\left(n\right)}{w}_j^{\left(n\right)H}{H}_{\mathrm{ij}}^{\left(n\right)}+{\mathrm{\σ}}^2{I_N}_r,$

Expression N _r* N _rThe dimension unit matrix.

Second step: the user receives i user's reception signal y according to the received beam figuration vector that calculates in the first step to sending signal _iRepresented by (1) formula.

Below in conjunction with Fig. 2 flow process of the present invention is further described:

1. initialization:

a)n=1；

B) each base station sends the wave beam forming vector by traditional SLNR scheme initialization

It is ${\mathrm{PL}}_{\mathrm{ii}}{H}_{\mathrm{ii}}^{(n-1)H}{H}_{\mathrm{ii}}^{(n-1)}$ With $\frac{{\mathrm{\σ}}^2}{P_i}{I_N}_t+\underset{j\≠i}{\mathrm{\Σ}}P{L}_{\mathrm{ji}}{H}_{\mathrm{ji}}^{(n-1)H}{H}_{\mathrm{ji}}^{(n-1)}$ Maximum generalized eigenvalue characteristic of correspondence vector, namely $w_i^{(n-1)}=\underset{\left|\right|w_i^{(n-1)}=1\left|\right|}{\max \mathrm{gen}.\mathrm{eigenvector}}({\mathrm{PL}}_{\mathrm{ii}}{H}_{\mathrm{ii}}^{(n-1)H}{H}_{\mathrm{ii}}^{(n-1)},\frac{{\mathrm{\σ}}^2}{P_i}{I_N}_t+\underset{j\≠i}{\mathrm{\Σ}}{\mathrm{PL}}_{\mathrm{ji}}{H}_{\mathrm{ji}}^{(n-1)H}{H}_{\mathrm{ji}}^{(n-1)});$

C) calculate

And between cooperative base station, share;

2. transmitting terminal:

A) high specific merging-ZF (MRC-ZF) the received beam figuration vector of interference user is estimated in each base station.(the MRC-ZF received beam figuration vector of j ≠ i) is the user j that base station i estimates

${\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)}\left(i\right)=\max .\mathrm{eigvector}\left({\hat{v}}_j^{\mathrm{MRC}(n-1)}{\hat{v}}_j^{\mathrm{MRC}(n-1)H}\text{+}{\mathrm{\β}}_{\mathrm{ji}}\frac{H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}{w}_i^{(n-1)H}{H}_{\mathrm{ji}}^{(n-1)H}}{{\left|\right|H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2}\right),$

Wherein, ${\mathrm{\β}}_{\mathrm{ji}}=-\frac{{\mathrm{PL}}_{\mathrm{ji}}{\left|\right|H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2}{\underset{k=1}{\overset{M}{\mathrm{\Σ}}}{\mathrm{PL}}_{\mathrm{ki}}{\left|\right|H_{\mathrm{ki}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2};$

B) the transmission wave beam forming vector of this base station current time is calculated in each base station:

$w_i^{\left(n\right)}=\frac{{\left({\mathrm{\Φ}}_i^{(n-1)}\right)}^{-1}{H}_{\mathrm{ii}}^{(n-1)H}{\hat{v}}_i^{\mathrm{MRC}(n-1)}}{\left|\right|{\left({\mathrm{\Φ}}_i^{(n-1)}\right)}^{-1}{H}_{\mathrm{ii}}^{(n-1)H}{\hat{v}}_i^{\mathrm{MRC}(n-1)}\left|\right|},$ Wherein, ${\mathrm{\Φ}}_i^{(n-1)}=\underset{j\≠i}{\mathrm{\Σ}}{P}_i{\mathrm{PL}}_{\mathrm{ji}}{H}_{\mathrm{ji}}^{(n-1)H}{\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)}\left(i\right){\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)H}\left(i\right)H_{\mathrm{ji}}^{(n-1)}+{\mathrm{\σ}}^2{I}_{N_t},$

Expression N _t* N _tThe dimension unit matrix;

C) transmission end of base station is according to the signal of the transmission wave beam forming vector that designs to service-user emission process wave beam forming;

D) each base station is calculated the received beam figuration vector estimated value of current time and is shared with each cooperative base station; ${\hat{v}}_i^{\left(n\right)}=\frac{H_{\mathrm{ii}}^{\left(n\right)}{w}_i^{\left(n\right)}}{\left|\right|H_{\mathrm{ii}}^{\left(n\right)}{w}_i^{\left(n\right)}\left|\right|};$

3. receiving terminal:

A) user uses formula (8) to calculate received beam figuration vector;

B) user uses the received beam figuration vector that designs to receive the signal that send each base station;

4.n ← n+1; Repeating step 2-4 is up to sign off.

Simulated effect of the present invention is as follows:

Consider seven cell seven users' scene, every antenna for base station number is 4, and every user antenna number is 2.Suppose that each base station is to the path loss of its service-user

Each base station is random number between the 0-1 to the path loss of interference user, i.e. PL _Ji=rand (1), i ≠ j.Channel model adopts Rayleigh channel, signal to noise ratio snr=10, and 20 time slots of emulation suppose that the transmitting power of each base station equates.To static channel with become channel slowly and carried out 10000 independently emulation respectively.

With the present invention and tradition do not consider to receive vector based on SLNR(T-SLNR) coordinates beam figuration scheme and having considered receive after the vector based on SLNR(JTR-CB) coordinates beam figuration scheme compare, the every user's of each time slot average spectral efficiency (ase) is as shown in Figure 3, Figure 4.From Fig. 3, Fig. 4 as can be seen under two kinds of channel conditions the present invention program than the coordinates beam figuration scheme of T-SLNR obvious lifting is arranged all on performance, though compare with the JTR-CB scheme and to also have certain gap, but required information interaction but is far smaller than the JTR-CB scheme, therefore has more feasibility than JTR-CB scheme.In the JTR-CB scheme, each cooperative base station need be shared whole channel condition informations (namely

), just can calculate all users at last one constantly received beam figuration vector, thereby estimate the transmission wave beam forming vector of this base station current time.And in the present invention program, each cooperative base station only need be shared the reception vector estimated based on the MRC criterion this base station (namely

), the information sharing amount only is the JTR-CB scheme

In addition, it can also be seen that from Fig. 3, Fig. 4 that the present invention program's convergence rate is very fast, therefore can change scene faster by adaptive channel.The average spectral efficiency (ase) of 20 time slots of each scheme sees Table 1, table 2.From table 1, table 2 as can be seen, the present invention program has improved 22.80% and 25.14% respectively than T-SLNR scheme every user's average spectral efficiency (ase) under two kinds of channel circumstances, and only than JTR-CB scheme low 9.92% and 10.13%.

User's average spectral efficiency (ase) of table 1 static channel different schemes

Watch 2 becomes user's average spectral efficiency (ase) of channel different schemes slowly

Claims (2)

1. one kind receives the coordinates beam shaping method that vector is estimated based on MRC-ZF, and it is characterized in that: this coordinates beam shaping method may further comprise the steps:

The first step, each cooperative base station is according to known channel condition information and last transmission wave beam forming vector constantly, estimate the received beam figuration vector of service-user with the mode of high specific merging, obtain high specific and merge received beam figuration vector estimated value, sharing separately then between cooperative base station, the high specific of service-user merges received beam figuration vector estimated value;

Second step, each cooperative base station merges received beam figuration vector estimated value and channel condition information according to the high specific of sharing the interference user that obtains, again the received beam figuration vector of interference user is carried out once obtaining high specific merging-ZF received beam figuration vector estimated value based on the estimation of high specific merging-ZF;

The 3rd step, each cooperative base station utilizes the high specific of service-user to merge the high specific merging-ZF received beam figuration vector estimated value of received beam figuration vector estimated value and interference user, make an uproar than being criterion with the leakage of maximization letter, calculate the transmission wave beam forming vector of current time.

2. according to the described a kind of coordinates beam shaping method of estimating based on MRC-ZF reception vector of claim 1, it is characterized in that: described coordinates beam shaping method specifically may further comprise the steps:

Consider a cooperative multicast system, this system contains M cooperative base station and M user, and i the service-user that the user is i base station, i=1, and 2 ..., M, the base station adopts the mode of coordinates beam figuration for user's service, uses PL _JiRepresent that i base station to j user's path loss, use H _JiRepresent that i base station to j user's channel matrix, suppose H _JiEach element separate and obey the multiple Gaussian Profile of zero-mean unit variance, the transmitting power of i base station is P _i, each user's reception noise is n _i, noise power is σ ², known its channel matrix to interior all users of cooperation set in each base station;

The first step: at transmitting terminal, the base station was at first estimated the received beam figuration vector of a last moment service-user based on the high specific merging criterion according to channel condition information and the transmission wave beam forming vector in a last moment, is got high specific and merge received beam figuration vector estimated value:

Represent last one constantly, high specific merging received beam figuration vector estimated value and the cooperative base station of service-user are shared in each base station, and the high specific that each base station, shared back all obtains all cooperative base station service-users merges received beam figuration vector estimated value ${\hat{v}}_i^{\mathrm{MRC}(n-1)},i=\mathrm{1,2},...,M;$

Second step: the high specific that share according to cooperative base station each base station merges the high specific merging-ZF received beam figuration vector estimated value that the known last moment channel condition information of received beam figuration vector estimated value and this base station calculates interference user, uses

The n-1 that expression base station i estimates is the high specific merging-ZF received beam figuration vector of user j constantly, j ≠ i, ${\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)}\left(i\right)$ For ${\hat{v}}_j^{\mathrm{MRC}(n-1)}{\hat{v}}_j^{\mathrm{MRC}(n-1)H}\text{+}{\mathrm{\β}}_{\mathrm{ji}}\frac{H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}{w}_i^{(n-1)H}{H}_{\mathrm{ji}}^{(n-1)H}}{{\left|\right|H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2}$ Eigenvalue of maximum characteristic of correspondence vector, wherein ${\mathrm{\β}}_{\mathrm{ji}}=-\frac{{\mathrm{PL}}_{\mathrm{ji}}{\left|\right|H_{\mathrm{ji}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2}{\underset{k=1}{\overset{M}{\mathrm{\Σ}}}{\mathrm{PL}}_{\mathrm{ki}}{\left|\right|H_{\mathrm{ki}}^{(n-1)}{w}_i^{(n-1)}\left|\right|}^2};$

The 3rd step: each base station utilizes the high specific of service-user to merge the high specific merging-ZF received beam figuration vector estimated value of received beam figuration vector estimated value and interference user, make an uproar than being the transmission wave beam forming vector that target is calculated this base station current time with the leakage of maximization letter, be shown below

Wherein, ${\mathrm{\Φ}}_i^{(n-1)}=\underset{j\≠i}{\mathrm{\Σ}}{P}_i{\mathrm{PL}}_{\mathrm{ji}}{H}_{\mathrm{ji}}^{(n-1)H}{\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)}\left(i\right){\hat{v}}_j^{\mathrm{MRC}-\mathrm{ZF}(n-1)H}\left(i\right)H_{\mathrm{ji}}^{(n-1)}+{\mathrm{\σ}}^2{I}_{N_t},$

Expression N _t* N _tThe dimension unit matrix;

The 4th step: after the 3rd step, the base station sends through the signal behind the wave beam forming to the user.

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