awgn.m

一些关于调指和解调的小程序

function [out1,out2]=AWGN(input,Eb_N0,Ps,k,R,P)

%*******************************************************************************************
%%% Note that SNR=(Eb/N0*R*k)/P, the Ps and Pn should calculated according to SNR, not Eb/N0 
%%% This function generate and add the AWGN noise to the tansmetted signals
%%% input and out are all "serial" sequence
%%% Eb_N0 : ratio of bit energy to noise power spectral density
%%% input : input signal sequence(complex numbers)
%%% Ps : average power of the signal
%%% rb : i.e. Eb/N0, raito of information bit energe to AWGN noise power spectral density
%%% k : the number of bits of each symbol
%%% R : coding rate
%%% P : spreading factor, i.e. "SF"
%*******************************************************************************************
L=length(input);

ebn=10^(Eb_N0/10);
SNR=(ebn.*R.*k)./P;
pow_s=Ps;
pow_n=pow_s/SNR;                     %%% noise average power(devided to real and imaginary parts,so devided by 2)
delta=sqrt(pow_n/2);

x=randn(1,L)*delta;
y=randn(1,L)*delta;
noise=x+j*y;

out1=noise+input;
out2=pow_n;