turbo_other_functions.c

一些关于Turbo编码译码实现所需的函数和原程序。

/*----------------------------------------------------------
* Copyright (c) 2003, 北京邮电大学移动通信实验室
* All rights reserved.
*
* 文件名称：turbo_other_functions.c
* 文件标识：
* 摘    要：Turbo仿真用文件.
*
* 当前版本：1.0
* 作    者：张鹏
* 完成日期：2003年12月1日
----------------------------------------------------------*/

#include "turbo_code_Log_MAP.h"
#include "turbo_other_functions.h"

extern double *alpha_channel;
double time_jarks = 0;

/*---------------------------------------------------------------
函数:
	void gen_source(int *data, int length)
介绍:
	产生随机信源.
参数:
	输入参数: length - 所需生成序列的长度.
	输出参数: data - 所生成bit序列的首址.
返回值:
	无
---------------------------------------------------------------*/
void gen_source(int *data, int length)
{
	double temp;
	int i;

	for (i=0; i<length; i++)
	{
		//temp = (double)rand()/RAND_MAX;
		temp = random_turbo();
		if (temp <= 0.5)
		{
			*(data+i) = 0;
		}
		else 
		{
			*(data+i) = 1;
		}
	}

}

/*---------------------------------------------------------------
函数:
	void AWGN(int *send, double *r, double sigma, int totallength)
介绍:
	AWGN信道.
参数:
	输入参数: send - int型发送数据首址.
			  sigma - 噪声标准差.
			  totallength - 序列长度.
	输出参数: r - 经AWGN信道后的数据序列的首址.
返回值:
	无
---------------------------------------------------------------*/
void AWGN(double *send, double *r, double sigma, int totallength)
{
	int i;
	double *noise = (double *)malloc(sizeof(double)*totallength);
	double seed =  (double)(3.0 - (double)((rand() & RAND_MAX)/(double)RAND_MAX)/10e6);
	mgrns(0,sigma,seed,totallength,noise);
	for(i=0; i<totallength; i++)
	{
		*(r+i) = (double)( *(send+i) + *(noise+i) );
	}
	free(noise);
}
/*---------------------------------------------------------------
函数:
	void mgrns(double mean,double sigma,double seed,int n,double *a)
介绍:
	产生长度为n的高斯随机序列.
参数:
	输入参数:	mean - 均值
				sigma - 标准差
				seed - 一个随机种子
	输出参数:	a - 长度为n的高斯随机序列.
返回值:
	无
---------------------------------------------------------------*/
void mgrns(double mean,double sigma,double seed,int n,double *a)
{ int i,k,m;
    double s,w,v,t;
    s=65536.0; w=2053.0; v=13849.0;
    for (k=0; k<=n-1; k++)
	{
		t=0.0;
		for (i=1; i<=12; i++)
        { 
			seed=seed*w+v; m=(int)(seed/s);
            seed=seed-m*s; t=t+(seed)/s;
        }/*按照中心极限定理产生服从高斯分布的随机数*/
        *(a+k)=mean+(double)(sigma*(t-6.0));
    }
    return;
}
/*---------------------------------------------------------------
函数:
	void rayleigh_channel_1226(double *send, double *r, double sigma, int totallength)
介绍:
	Rayleigh信道.
参数:
	输入参数: send - double型发送数据首址.
			  sigma - 噪声标准差.
			  totallength - 序列长度.
	输出参数: r - 经Rayleigh信道后的数据序列的首址.
返回值:
	无
---------------------------------------------------------------*/
void rayleigh_channel_1226(float *send, float *r, double sigma, int totallength)
{
	int i;
	double *noise = (double *)malloc(sizeof(double)*totallength);

	int seed=abs((rand()*100000)%RAND_MAX);

	chan_gauss(0, sigma, totallength, noise, &seed);

	for(i=0; i<totallength; i++)
	{
		*(r+i) =(float)( *(send+i) * (*(alpha_channel+i)) + *(noise+i));
	}

	free(noise);
}

/*---------------------------------------------------------------
函数:
	void chan_gauss(double mean, double sigma,int Ns, double *gauss, int *seed)
介绍:
	产生长度为Ns的高斯随机序列.
参数:
	输入参数:	mean - 均值
				sigma - 标准差
				seed - 一个随机种子
	输出参数:	gauss - 长度为Ns的高斯随机序列.
返回值:
	无
---------------------------------------------------------------*/
void chan_gauss(double mean,double sigma, int Ns, double *gauss, int *seed)
{
	int i;
	double xita;
	double z;
	double ssigma=-2*sigma*sigma;
	for(i=0;i<Ns;i++)
	{
	   z=(double)(sqrt(ssigma*log(1-chan_uniform(seed))));
	   xita=chan_uniform(seed);
	   gauss[i]= (double)(mean+z*cos(2*3.14159265*xita));
	}
}

/*---------------------------------------------------------------
函数:
	double chan_uniform(int *seed)
介绍:
	0-1均匀分布随机数发生器.
参数:
	输入参数: seed - 指向随机种子的指针.
	输出参数: 无.
返回值:
	生成的随机数.
---------------------------------------------------------------*/
double chan_uniform(int *seed)
{
		double t;
		*seed=2045*(*seed)+1;
		*seed=*seed-(*seed/1048576)*1048576;
		t=(*seed)/(double) 1048576.0;	
		return(t);

}
/*---------------------------------------------------------------
函数:
	void chan_jakes(double *rayleigh, double fd, double fs, int Ns)
介绍:
	Jakes模型,用以产生rayleigh衰落系数.
参数:
	输入参数:	fd - 多谱勒频移.
				fs - rayleigh采样系数.
				Ns - 序列长度.
	输出参数:	rayleigh - 生成的rayleigh序列的首址.
返回值:
	无
---------------------------------------------------------------*/
void chan_jakes(double *rayleigh, double fd, double fs, int Ns)
{
	int i,j,N;	
	double t,temp_1,temp_2,fai,*fai_i,*fai_q,*wn,wm,nn0,nn1,nn21,nn22,nn3;
    double *rayleigh_I;
	double *rayleigh_Q;
	double deta;
	N=2*(2*N0+1);
	nn0=(double)(1/(N0+1.0));
	nn1=(double)(1/(N+0.0));
    nn21=(double)(1/sqrt(2*N0));
	nn22=(double)(1/sqrt(2*N0+2));
    //allocate memory
    if (((fai_i)= (double *) malloc((N0+1)*sizeof(double))) == NULL)
	{
	     printf("Not enough memory to allocate buffer ex_array\n");	     
		 exit(1);	    
	} 
	if (((fai_q)= (double *) malloc((N0+1)*sizeof(double))) == NULL)
	{
	     printf("Not enough memory to allocate buffer ex_array\n");	     
		 exit(1);	    
	} 
	if (((wn)= (double *) malloc((N0+1)*sizeof(double))) == NULL)
	{
	     printf("Not enough memory to allocate buffer ex_array\n");	     
		 exit(1);	    
	}
	if (((rayleigh_I)= (double *) malloc(Ns*sizeof(double))) == NULL)
	{
	     printf("Not enough memory to allocate buffer rayleigh_I\n");	     
		 exit(1);	    
	} 
	if (((rayleigh_Q)= (double *) malloc(Ns*sizeof(double))) == NULL)
	{
	     printf("Not enough memory to allocate buffer rayleigh_Q\n");	     
		 exit(1);	    
	} 
	fai_i[N0]=1;
	fai_q[N0]=0;
	wm=(double)(2*PI*fd);
	temp_1=0;
	temp_2=0;
	for (i=0;i<N0;i++)
	{		 
		 fai=(double)(PI*(i+1)*nn0);
		 *(fai_i+i)=(double) (cos(fai));
		 *(fai_q+i)=(double) (sin(fai));
		 *(wn+i)=(double) (wm*cos(2*PI*(i+1)*nn1));
	}
	//pruduce Ns sample point 
	deta=1/fs;
	for(i=0,t=time_jarks;i<Ns;i++,t+=deta)
	{ 
		for(j=0;j<N0;j++)
		{	
			nn3=(double)(cos(*(wn+j)*t));
			temp_1+=(double) (*(fai_i+j)*nn3);
			temp_2+=(double) (*(fai_q+j)*nn3);
		}       
		*(rayleigh_I+i)=(double) ((2*temp_1+1.4142136*fai_i[N0]*cos(wm*t))*nn21);
        *(rayleigh_Q+i)=(double) ((2*temp_2+1.4142136*fai_q[N0]*cos(wm*t))*nn22);	
        *(rayleigh+i)=(double) (sqrt(*(rayleigh_I+i)*(*(rayleigh_I+i))+*(rayleigh_Q+i)*(*(rayleigh_Q+i))));	
		temp_1=0;
		temp_2=0;
	} 
	time_jarks = t;

	//set point free
	free(fai_i);
	free(fai_q);
	free(wn);
	free(rayleigh_I);
	free(rayleigh_Q);	
}



void combo(int *trafficflow_sourceA,int *trafficflow_sourceB,int *trafficflow_sourceAB)
{
	int i;
	for(i=0;i<FRAME_LENGTH;i++)
	{
		*(trafficflow_sourceAB+2*i)=*(trafficflow_sourceA+i);
		*(trafficflow_sourceAB+2*i+1)=*(trafficflow_sourceB+i);
	}
}

void doublecombo(double *Le_turboA,double *Le_turboB,double *Le_turboAB)
{
	int i;
	for(i=0;i<FRAME_LENGTH;i++)
	{
		*(Le_turboAB+2*i)= *(Le_turboA+i);
		*(Le_turboAB+2*i+1)= *(Le_turboB+i);
	}
}

void doubledecombo(double *La_turboAB,double *La_turboA,double *La_turboB)
{
	int i;
	for(i=0;i<FRAME_LENGTH;i++)
	{
		*(La_turboA+i)=*(La_turboAB+2*i);
		*(La_turboB+i)=*(La_turboAB+2*i+1);	
	}
}
void comboinfoAB(double *infoAB,double *yk_turboA,double *yk_turboB)
{
	int i;
	for(i=0 ; i<FRAME_LENGTH;i++)
	{
		*(infoAB+2*i)=*(yk_turboA+2*i);
		*(infoAB+2*i+1)=*(yk_turboB+2*i);
	}
}