channel.m

此代码是ＬＤＰＣ码进行BP算法的重要参考代码

function rx_signal = channel(tx_signal, SNR);

len = size(tx_signal, 2);

% calculate noise variance
noise_var = 1/(10^(SNR/10));
noise = sqrt(noise_var/2) * (randn(1, len) + j*randn(1, len));

% Add noise
rx_signal = tx_signal+noise;