hello, I'm having problems implementing the correct beamforming and don't know where I'm making mistakes. I think the problem is with the created signal. What's happening is that the beampattern of the adpative filter and as well the optimum MVDR filter are putting gains in the interferes and nulling the signal of interest. And as you can see in the program below I'm just constraint the unitary gain in the direction of the signal of interest. So if anyone could help, I would be very greatful. Here is the programs I'm using: Main program: NS = 200000; % number of samples NSENS = 10; % number of sensors THETAs = [0;-20;43]; % DOAs FS = 1000; % sample frequency SIG_FREQ = 10; % signals frequency NE = 1; % number of ensambles NUSER = length(THETAs); % number of users % compute the steering vector M = (0:NSENS-1)'; THETAs_rad = deg2rad(THETAs); PHI = pi*sin(THETAs_rad); SV = exp(-j*M*PHI'); % compute CLMS C = SV(:,1); f = 1; P = (eye(NSENS) - C*pinv(C'*C)*C'); F = (C*pinv(C'*C)*f); MU = 1e-4; % algoritm step-size RXX = zeros(NSENS,NSENS,NE); RXX_T = zeros(NSENS,NSENS); for k=1:NE [SIG_OUT,SIG_INT,SIG_INTER] = g_signals(NS,NSENS,THETAs,FS,SIG_FREQ); OUT = zeros(NS,1); W1 = zeros(NSENS,NS+1); W1(:,1) = F; for kk=1:NS X = SIG_OUT(:,kk); OUT(kk) = W1(:,kk)'*X; W1(:,kk+1) = P*(W1(:,kk) - MU*OUT(kk)'*X) + F; end RXX = RXX + (SIG_OUT*SIG_OUT')./NS; W1o = W1(:,end); end RXX_T = RXX./NE+0.0001*eye(NSENS); Wo = inv(RXX_T)*C*inv(C'*inv(RXX_T)*C)*f; figure(1) plot_BP(Wo,NSENS) hold on plot_BP(W1o,NSENS,'--k') ---------------- the program that generate the signals, g_signals, is: function [SIG_OUT,SIG_INT,SIG_INTER] = g_signals(NS,NSENS,THETAs,FS,SIG_FREQ) NUSER = length(THETAs); % number of users % compute the steering vector M = (0:NSENS-1)'; THETAs_rad = deg2rad(THETAs); PHI = pi*sin(THETAs_rad); SV = exp(-j*M*PHI'); % discrete time vector T = (0:1/FS:(NS-1)/FS)'; % generating signals SIGNAL_G = exp(j*2*pi*SIG_FREQ*T); SIG_OUT = zeros(NSENS,NS); SIG_INT = zeros(NSENS,NS); SIG_INTER = zeros(NSENS,NS,NUSER-1); % putting DOA to the signals TEMP = zeros(NSENS,NS); SIG_INT = SV(:,1)*SIGNAL_G.'; for k=2:NUSER SIG_INTER(:,:,k) = SV(:,k)*SIGNAL_G.'; TEMP = TEMP + SIG_INTER(:,:,k); end SIG_OUT = awgn(TEMP + SIG_INT,20); % adding white noise ---------------------------------- the program to plot the beampatterns is: function beam_pattern(WM,NSENS,type_color) D = 0:NSENS-1; u = -pi:0.001:pi; V2 = exp(-j*D.'*u); G1 = WM'*V2 ; u2 = asin(u/pi); u3 = u2*180/pi; if (nargin == 2) type_color='-b'; end plot(u3,20*log10(abs(G1)),type_color); title('\bf Gain x DOA','Fontsize',32); axis([-90 90 -40 10]); xlabel('\it DOA','Fontsize',20); ylabel('Beam pattern (dB)','Fontsize',20); thanks in advance for any help.

# Problem with Beamforming Implementation in MATLAB

Started by ●December 16, 2009