function [pr, soft_bits] = rx_bpsk_demod(rx_symbols, SNR)

soft_bits = real(rx_symbols); 

%noise_var = 1/(10^(SNR/10));
%pr=exp(-(real(rx_symbols-1).^2+imag(rx_symbols-1).^2-real(rx_symbols+1).^2-imag(rx_symbols+1).^2)/noise_var);
alpha = 10^(SNR/10);
pr=exp(-(real(rx_symbols-1).^2+imag(rx_symbols-1).^2-real(rx_symbols+1).^2-imag(rx_symbols+1).^2)*alpha);