channel.cpp

包括RS码的编码,硬(BM)/软(KV)译码,AWGN信道调制解调仿真. 具体采用何种编译码方案和调制解调方式可在Profile.txt文件中指定(内有详细说明). 且扩展性极好,容易向其中加入新的调

#include <stdafx.h>
#include <math.h>
#include "channel.h"

AWGN NewAWGN(double coderate, double snr) {
	double var=sqrt(1/(2*(coderate)*(pow(10.0,(snr)/10))));
	double Sqrt2PieVar=var*sqrt(2*PI);
	double SqrVar2=2*var*var;
	AWGN awgn={30323, 173, 23, snr, coderate, var, Sqrt2PieVar, SqrVar2};
	return awgn;
}

double random_u(struct AWGN *gauss)
{ 
    double temp;
    gauss->ix = (gauss->ix*249) % 61967; 
    gauss->iy = (gauss->iy*251) % 63443;
    gauss->iz = (gauss->iz*252) % 63599;
    temp= ( (double)gauss->ix/(double)61967 + (double)gauss->iy/(double)63443+ (double)gauss->iz/(double)63599 )
	   -(int)( (double)gauss->ix/(double)61967+ (double)gauss->iy/(double)63443+(double)gauss->iz/(double)63599 );
    return(temp);     
}

double gauss_g(struct AWGN *gauss)
{
    double u1,u2;
    double x;    
    u1=random_u(gauss);
    u2=random_u(gauss);
    x=gauss->var*(double)sqrt((double)(-2)*log((double)1-u1))*(double)cos((double)2*(double)PI*u2);
    /*** 常数系数指标准差 ***/
    return(x);
}


void awgn_channel (int input[] , double output[] , AWGN *gauss , int len)
{
	int i;
	double add;
	int COLUMN;
	COLUMN = len;
	for (i=0;i<COLUMN;i++)
	{
	    add = gauss_g(gauss);
	    output[i] = input[i] + add;
	}
}

/*注意：信号功率为1*/
double AWGNRuined(int input, AWGN* gauss) {
	return ((double)input+gauss_g(gauss));
}

double AWGNRuined(double input, AWGN* gauss) {
	return (input+gauss_g(gauss));
}

void AWGNRuin(double* amp, int len, AWGN* gauss)
{
	for (int i=0; i<len; i++) amp[i]+=gauss_g(gauss);
}