random_interleaver.cpp

Turbo 码的logmap算法实现。用于通信系统仿真

//Author NiuKai
//Date July,28th 2002
//Function random interleaving

#include "PCCC_para.h"

void Random_interleaver(float data[],int index[],int method,int buffer_len)
{  int i,j,k;
   int *buffer;
   float *pool;
   buffer=(int *)calloc(buffer_len,sizeof(int));
   pool=(float *)calloc(buffer_len,sizeof(float));
   int temp;
   switch(method)
   {  case 0 :          //first interleaving
                 for(i=0;i<buffer_len;i++)
                 {     buffer[i]=rand();
                       index[i]=i;
                 }
                 //sort 
                 for(i=0;i<buffer_len;i++)
                 {     k=i;
                       for(j=i+1;j<buffer_len;j++)
                            if(buffer[j]<buffer[k])    k=j;
                       temp=buffer[k];buffer[k]=buffer[i];buffer[i]=temp;
                       temp=index[k];index[k]=index[i];index[i]=temp;
                 }      
                 
                 for(i=0;i<buffer_len;i++) 
                      pool[index[i]]=data[i];
                 for(i=0;i<buffer_len;i++)
                      data[i]=pool[i];
                 break;
      case 1 :          //other interleaving
                 for(i=0;i<buffer_len;i++) 
                      pool[index[i]]=data[i];
                 for(i=0;i<buffer_len;i++)
                      data[i]=pool[i];
                 break;
      case 2 :          //deinterleaving
                for(i=0;i<buffer_len;i++)
                      pool[i]=data[index[i]];
                for(i=0;i<buffer_len;i++)
                      data[i]=pool[i];
                break;
      default :  printf("\nplease input correct interleaving method!\n");
   }
   free(buffer);
   free(pool);
}