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## Beamforming matlab code | Beamforming QAM matlab source code

This page of MATLAB source code covers Beamforming matlab code. The output plots and mathematical equations of Beamforming QAM modulation matlab code are mentioned. QAM modulation stands for Quadrature Amplitude Modulation.

Introduction:
Beamforming is the technique used to boost the vector signal before transmission with the help of multiple antenna array. It helps in increasing coverage of cell tower to reach farthest mobile subscribers. Following are the main types of beamforming techniques.
• Analog Beamforming
• Digital Beamforming
• Hybrid Beamforming Figure-1 depicts analog beamforming transmitter block diagram. Refer Analog Beamforming versus Digital Beamforming basics>> and Hybrid Beamforming basics and types>>.

### Beamforming matlab code

clear
N = 10^6
nTx = 2;
M=4;
k = sqrt(1/((2/3)*(M-1)));
m = [1:sqrt(M)/2];
alphaMqam = [-(2*m-1) 2*m-1];
Eb_N0_dB = [0:30];
ipHat1 = zeros(1,N);
ipHat2 = zeros(1,N);
for ii = 1:length(Eb_N0_dB)
ip = randsrc(1,N,alphaMqam) + j*randsrc(1,N,alphaMqam);
s = k*ip; % normalization of energy to 1
n = 1/sqrt(2)*[randn(1,N) + j*randn(1,N)]; % white guassian noise, 0dB variance
h = 1/sqrt(2)*[randn(nTx,N) + j*randn(nTx,N)]; % Rayleigh channel
sr = (1/sqrt(nTx))*kron(ones(nTx,1),s);
% Channel and noise Noise addition
h_tx = h.*exp(-j*angle(h));
y1 = sum(h.*sr,1) + 10^(-Eb_N0_dB(ii)/20)*n;
y2 = sum(h_tx.*sr,1) + 10^(-Eb_N0_dB(ii)/20)*n;
y1Hat = y1./sum(h,1);
y2Hat = y2./sum(h_tx,1);
% demodulation
y_re1 = real(y1Hat)/k; % real part
y_im1 = imag(y1Hat)/k;
y_re2 = real(y2Hat)/k; % real part
y_im2 = imag(y2Hat)/k; % imaginary part
ipHat_re1 = 2*floor(y_re1/2)+1;
ipHat_re1(find(ipHat_re1>max(alphaMqam))) = max(alphaMqam);
ipHat_re1(find(ipHat_re1<min(alphaMqam))) = min(alphaMqam);
ipHat_re2 = 2*floor(y_re2/2)+1;
ipHat_re2(find(ipHat_re2>max(alphaMqam))) = max(alphaMqam);
ipHat_re2(find(ipHat_re2<min(alphaMqam))) = min(alphaMqam);
ipHat_im1 = 2*floor(y_im1/2)+1;
ipHat_im1(find(ipHat_im1>max(alphaMqam))) = max(alphaMqam);
ipHat_im1(find(ipHat_im1<min(alphaMqam))) = min(alphaMqam);

ipHat_im2 = 2*floor(y_im2/2)+1;
ipHat_im2(find(ipHat_im2>max(alphaMqam))) = max(alphaMqam);
ipHat_im2(find(ipHat_im2<min(alphaMqam))) = min(alphaMqam);
ipHat1 = ipHat_re1 + j*ipHat_im1;
nErr1(ii) = size(find([ip- ipHat1]),2); % counting the number of errors
ipHat2 = ipHat_re2 + j*ipHat_im2;
nErr2(ii) = size(find([ip- ipHat2]),2); % counting the number of errors
end
simBer1 = nErr1/N; % simulated ber (no beam forming)
simBer2 = nErr2/N; % simulated ber (with beam forming)
theoryBerAWGN = 0.5*erfc(sqrt(10.^(Eb_N0_dB/10))); % theoretical ber
EbN0Lin = 10.^(Eb_N0_dB/10);
theoryBer = 0.5.*(1-sqrt(EbN0Lin./(EbN0Lin+1)));
p = 1/2 - 1/2*(1+1./EbN0Lin).^(-1/2);
theoryBer_nRx2 = p.^2.*(1+2*(1-p));
close all
figure
semilogy(Eb_N0_dB,simBer1,'ks-','LineWidth',2);
hold on
semilogy(Eb_N0_dB,simBer2,'rx-','LineWidth',2);
axis([0 35 10^-5 0.5])
grid on
legend('2Tx-1Rx (no Beamforming-sim)','2Tx-1Rx (Beamforming-sim)');
xlabel('Eb/No, dB');
ylabel('Bit Error Rate');
title('BER for QAM modulation in Rayleigh Fading channel');

### Input and Output of Beamforming QAM matlab source code

Run the downloaded BeamformingQAM.m file after unzipping the folder. We will get output matlab image as follows. 