function noise = get_noise(noise_sigma, N, M, type)
    if nargin < 4
        type = "complex";
    end
    
    if type == "complex"
        noise = random('Normal', 0, noise_sigma / sqrt(2), N, M) + 1j * random('Normal', 0, noise_sigma / sqrt(2), N, M);
    else
        noise = random('Normal', 0, noise_sigma, N, M);
    end
end