CN109104228A - A kind of algorithm of wave beam forming - Google Patents

Abstract

The invention discloses a kind of algorithms of wave beam forming, transmitting signal calculates each user that the signal of antenna is sent to user area by weighing vector, it includes that down beam shaping algorithm and down channel are estimated that weighing vector, which calculates, multibeam antenna is at work, antenna pattern shape is basically unchanged, it covers entire user area using multiple parallel beams, the direction of each wave beam is fixed, beam angle is also determined with number of antenna elements, antenna is completed subscriber signal using adaptive antenna least mean square algorithm and is sended and received, the algorithm structure is simple, it is at low cost, anti-multipath jamming effect is obvious, jamming power is bigger, and its anti-jamming effectiveness is better, multibeam antenna is at work, antenna pattern shape is basically unchanged, it covers entire user area using multiple parallel beams, the direction of each wave beam is fixed, beam angle It is determined with number of antenna elements, calculates the weight for distributing to mobile station, increase the capacity of the down channel of single cell.

Description

A kind of algorithm of wave beam forming

Technical field

The present invention relates to a kind of algorithm more particularly to a kind of algorithms of wave beam forming.

Background technique

With the development of microcomputer and Digital Signal Processing, intelligent antenna technology has become in mobile communication most One of attractive technology.Due to being limited by Principle of Communication, smart antenna is usually applied to the base in mobile communication It stands end, basic thought is the difference of the orthogonality and each subscriber signal space characteristics using mutiple antennas unitary space, is used Array antenna technology automatically adjusts the weighing vector of each antenna array according to certain acceptance criteria, generates spatial orientation wave beam, makes Antenna main beam is directed at subscriber signal arrival direction, and secondary lobe or null point are directed at interference signal arrival direction, to reach sufficiently high Effect ground utilizes the useful signal of mobile subscriber and inhibits or delete the purpose of interference signal, thus reach optimum reception and transmitting, So that the signal for sending and receiving multiple users on the same channel does not interfere mutually, by same frequency or same time slot, with code channel Signal distinguishing comes, and maximally utilises limited channel resource, can be by intelligence according to the antenna pattern shape of use Antenna is divided into two classes: multi-beam intelligent antenna and adaptive direction figure smart antenna.

Currently, people focus mostly in uplink for the research of smart antenna.Although people are in research intelligent antenna beam shape At when eliminate in view of interfering the cochannel in uplink, the influence of multi-access inference and multipath fading, however, following shifting Dynamic traffic demands will lead to downlink capacity much larger than up-link capacity, on existing beamforming algorithm cannot effectively guarantee While row Wave beam forming, increase the capacity of downlink wave beam

Summary of the invention

The object of the present invention is to provide a kind of algorithms of wave beam forming, solve customer service since the every field acquisition of knowledge is not complete Face leads to the insurmountable problem of problem.

In order to achieve the above object, the present invention is achieved by the following technical solutions:

The present invention provides a kind of algorithm of wave beam forming, and transmitting signal is calculated by weighing vector and sends the signal of antenna To each user of user area, it includes that down beam shaping algorithm and down channel are estimated that weighing vector, which calculates, multibeam antenna At work, antenna pattern shape is basically unchanged, and covers entire user area, the finger of each wave beam using multiple parallel beams To be it is fixed, beam angle is also determined with number of antenna elements, antenna using adaptive antenna least mean square algorithm complete use Family signal sends and receivees.

Preferably, adaptive beam least mean square algorithm principle is as follows:

Reference signal is d (n), and digital beam froming network processes function is W, then the output signal of system are as follows:

Y (n)=W^Tx_N(n) (1)

Its error are as follows: e (n)=dn-W^Tx_N(n)=d (n)-xN^T(n)W (2)

Wherein: Rxd is the cross-correlation coefficient of useful signal and reference signal, and Rxd is the auto-correlation coefficient of useful signal, right W takes gradient, then enabling it is that zero can obtain: W_OPT=R_XX ^-1R_xd。

Preferably, when reference waveform signal d (n), best weight value can be obtained, method is:

Wherein μ is constant, it determines leg speed degree.

Preferably, w in down beam shaping algorithm^(k,ka)Indicate k-th of user, kth_aWeighting coefficient (the k=of a antenna 1,2,3 ..., K；k_a=1,2 ..., k_a)

Wherein K indicates number of users, k_aIndicate antenna number.

Preferably, weight vector is w=[w₁,w₂,…w_ka]^T, the output of down beam shaping are as follows:

w_ka=[w^(1,ka),w^(2,ka),…,w^(k,ka)]^T

D=[d₁, d₂..., d_k]^T

Y=[y₁, y₂..., y_k]^T

Y=wd (5)

Wherein w_kaIndicate that the weighting coefficient of the Ka each user of antenna, d are expressed as transmitting signal.

Preferably, down channel estimation considers that the signal-to-noise ratio made it is expected when user receives signal is maximum, then full vector is wanted Meet

w_k=argmax { SNR_K}=argmax { w_K ^HR_dkw_k}

Wherein, R_dkIt is the downlink signal covariance matrix for it is expected user (k-th of user), i indicates unit matrix.

Beneficial effects of the present invention: the algorithm structure is simple, at low cost, and anti-multipath jamming effect is obvious, and jamming power is got over Its big anti-jamming effectiveness is better, and at work, antenna pattern shape is basically unchanged multibeam antenna, utilizes multiple and traveling wave Beam covers entire user area, the direction of each wave beam be it is fixed, beam angle is also determined with number of antenna elements.When user exists When moving in cell, it determines the arrival direction of subscriber signal by direction finding, and it is suitable then to be chosen according to the arrival direction of signal Array element weighting, the main lobe of directional diagram is directed toward user direction, to improve the signal-to-noise ratio of user, only based on down channel algorithm Only need to know base station to the mobile station to be emitted descending transmission channel second-order statistic, calculate and distribute to mobile station Weight, this method can increase the capacity of the down channel of single cell, to improve the capacity of whole system, solve future The problem of smart antenna internal channel off-capacity, decrease the use cost of smart antenna.

Detailed description of the invention

Fig. 1 is the overall structure diagram of beamforming algorithm.

Specific embodiment

With reference to embodiment, the specific embodiment of the present invention is further described.Following embodiment is only used for more Add and clearly demonstrate technical solution of the present invention, and not intended to limit the protection scope of the present invention.

Embodiment 1

A kind of algorithm of wave beam forming, specifically includes:

Transmitting signal calculates each user that the signal of antenna is sent to user area, weighing vector meter by weighing vector Calculate includes that down beam shaping algorithm and down channel estimate that at work, antenna pattern shape is substantially not for multibeam antenna Become, cover entire user area using multiple parallel beams, the direction of each wave beam be it is fixed, beam angle is also with antenna element Number and determine, antenna using adaptive antenna least mean square algorithm complete subscriber signal send and receive, adaptive beam is most Small mean square algorithm principle is as follows:

Reference signal is d (n), and digital beam froming network processes function is W, then the output signal of system are as follows:

Y (n)=W^Tx_N(n) (1)

Its error are as follows: e (n)=dn-W^Tx_N(n)=d (n)-xN^T(n)W (2)

Wherein: Rxd is the cross-correlation coefficient of useful signal and reference signal, and Rxd is the auto-correlation coefficient of useful signal, right W takes gradient, then enabling it is that zero can obtain: W_OPT=R_XX ^-1R_xd, when reference waveform signal d (n), best weight value can be obtained, method is:

Wherein μ is constant, it determines leg speed degree, w in down beam shaping algorithm^{(k, ka)}Indicate k-th of user, kth_a Weighting coefficient (k=1,2,3 ..., K of a antenna；k_a=1,2 ..., k_a), wherein K indicates number of users, k_aIndicate antenna number, power Vector is w=[w₁,w₂,…w_ka]^T, the output of down beam shaping are as follows:

w_ka=[w^{(1, ka)},w^{(2, ka)},…,w^{(k, ka)}]^T

D=[d₁,d₂,…,d_k]^T

Y=[y₁,y_2,…,y_k]^T

Y=wd (5)

Wherein w_kaIndicate that the weighting coefficient of the Ka each user of antenna, d are expressed as transmitting signal, down channel estimation considers Make it is expected that signal-to-noise ratio when user receives signal is maximum, then full vector will meet

w_k=argmax { SNR_K}=argmax { w_K ^HR_dkw_k}

Wherein, R_dkIt is the downlink signal covariance matrix for it is expected user (k-th of user), i indicates unit matrix

Embodiment 2

When user moves in the cell, it determines the arrival direction of subscriber signal by direction finding, then according to signal Arrival direction chooses suitable array element weighting, the main lobe of directional diagram is directed toward user direction, to improve the signal-to-noise ratio of user, base In down channel algorithm it is only necessary to know base station to the mobile station to be emitted descending transmission channel second-order statistic, calculate The weight of mobile station is distributed to out, and this method can increase the capacity of the down channel of single cell, to improve entire system The capacity of system.

The foregoing is only a preferred embodiment of the present invention, but scope of protection of the present invention is not limited thereto, Anyone skilled in the art in the technical scope disclosed by the present invention, according to the technique and scheme of the present invention and its Inventive concept is subject to equivalent substitution or change, should be covered by the protection scope of the present invention.

Claims (6)

1. a kind of algorithm of wave beam forming, which is characterized in that transmitting signal is calculated by weighing vector and sends the signal of antenna To each user of user area, it includes that down beam shaping algorithm and down channel are estimated that weighing vector, which calculates, multibeam antenna At work, antenna pattern shape is basically unchanged, and covers entire user area, the finger of each wave beam using multiple parallel beams To be it is fixed, beam angle is also determined with number of antenna elements, antenna using adaptive antenna least mean square algorithm complete use Family signal sends and receivees.

2. a kind of algorithm of wave beam forming according to claim 1, which is characterized in that adaptive beam least mean square algorithm Principle is as follows:

Reference signal is d (n), and digital beam froming network processes function is W, then the output signal of system are as follows: y (n)=W^Tx_N (n) (1)

Its error are as follows: e (n)=dn-W^Tx_N(n)=d (n)-xN^T(n)W (2)

Wherein: Rxd is the cross-correlation coefficient of useful signal and reference signal, and Rxd is the auto-correlation coefficient of useful signal, is taken to W Gradient, then enabling it is that zero can obtain: W_OPT=R_XX ^-1R_xd。

3. a kind of algorithm of wave beam forming according to claim 2, which is characterized in that, can when reference waveform signal d (n) Best weight value is obtained, method is:

Wherein μ is constant, it determines leg speed degree.

4. a kind of algorithm of wave beam forming according to claim 1, which is characterized in that w in down beam shaping algorithm^{(k ,ka)}Indicate k-th of user, kth_aWeighting coefficient (k=1,2,3 ..., K of a antenna；k_a=1,2 ..., k_a)

Wherein K indicates number of users, k_aIndicate antenna number.

5. a kind of algorithm of wave beam forming according to claim 4, which is characterized in that weight vector is w=[w₁,w₂,…w_ka]^T, The output of down beam shaping are as follows:

w_ka=[w^(1,ka),w^(2,ka),…,w^(k,ka)]^T

D=[d₁,d₂,…,d_k]^T

Y=[y₁,y₂,…,y_k]^T

Y=wd (5)

Wherein w_kaIndicate that the weighting coefficient of the Ka each user of antenna, d are expressed as transmitting signal.

6. a kind of algorithm of wave beam forming according to claim 1, which is characterized in that down channel estimation considers to make it is expected User receives signal-to-noise ratio maximum when signal, then full vector will meet

w_k=argmax { SNR_K}=argmax { w_K ^HR_dkw_k}

Wherein, R_dkIt is the downlink signal covariance matrix for it is expected user (k-th of user), i indicates unit matrix.