# Bit Error Rate High Values

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Kawther on 1 Dec 2014
I am using this code to find the bit error rate for the Kmeans clustering algorithm for receving a QPSK modulated data. Running the code high BER values are obtained (something more than 80). Can anyone help me with that ASAP.
clear all clc T=[ 2+2*i 2-2*i -2+2*i -2-2*i]; A=randn(150,2)+2*ones(150,2); C=randn(150,2)-2*ones(150,2); B=randn(150,2)+2*ones(150,2); F=randn(150,2)-2*ones(150,2); D=randn(150,2)+2*ones(150,2); G=randn(150,2)-2*ones(150,2); E=randn(150,2)+2*ones(150,2); H=randn(150,2)-2*ones(150,2); X = [A; B; D; C; F; E; G; H]; for k=1:5 [idx, centroids] = kmeans(X, k, 'Replicates', 20); x = X(:,1); y = X(:,2); BER=[]; for nn=1:4 ber=0; gt = zeros(1,4); for idx = 1 : 4 [dummy,gt(idx)] = min(sum(bsxfun(@minus, [real(T(idx)), imag(T(idx))],... centroids).^2, 2)); end randn('seed',123); rand_ind = randi(4, 10, 1); test_sequence = T(rand_ind); gt_labels = gt(rand_ind); x = real(test_sequence).*(nn*randn(1, 10)); y = imag(test_sequence).*(nn*randn(1, 10)); labels = zeros(1, 10); for idx = 1 : 10 [dummy,labels(idx)] = min(sum(bsxfun(@minus, [x(idx), y(idx)],... centroids).^2, 2)); end ber = sum(labels ~= gt_labels) / 10 * 100; BER=[BER ber]; end plot(nn,BER) end Thank you very much Kawther