Bit Error Rate High Values

2 次查看（过去 30 天）

显示更早的评论

Kawther 2014-12-1

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/164905-bit-error-rate-high-values

关闭： MATLAB Answer Bot 2021-8-20

在 MATLAB Online 中打开

Dear All,

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