transmit.c

用于LDPC编码译码的仿真实现。包括随机生成校验矩阵、由校验矩阵产生生成矩阵、编码、加随机噪声、译码等内容。原作者是老外

/* TRANSMIT.C - Simulate transmission of bits through a channel. */

/* Copyright (c) 2000, 2001 by Linxuehong
 *
 * Permission is granted for anyone to copy, use, or modify this program 
 * for purposes of research or education, provided this copyright notice 
 * is retained, and note is made of any changes that have been made. 
 *
 * This program is distributed without any warranty, express or implied.
 * As this program was written for research purposes only, it has not been
 * tested to the degree that would be advisable in any important application.
 * All use of this program is entirely at the user's own risk.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#include "transmit.h"
#include "open.h"
#include "rand.h"


void transmit
(
  double *tdata,  //the transmit data
  double *rdata,  // the receive data
  int data_length,
  int seed,
  double sgma
  )
{
  int i;
  
  double awgn_noise;

  
  /* Set random seed to avoid duplications with other programs. */

  rand_seed(10*seed+3);

  /* Transmit bits. */

 for (i=0;i<data_length;i++)
 {
	 awgn_noise=sgma*rand_gaussian(seed);
	 rdata[i]=tdata[i]+awgn_noise;
	// printf("%f ",rdata[i]);
 }

}


/*transmit for BPSK*/

void bpsk_transmit
(
  int *tdata,  //the transmit data
  double *rdata,  // the receive data
  int data_length,
  int seed,
  double sgma
)
{
  int i;
  
  double awgn_noise;

  
  /* Set random seed to avoid duplications with other programs. */

  rand_seed(10*seed+3);

  /* Transmit bits. */

 for (i=0;i<data_length;i++)
 {
	 awgn_noise=sgma*rand_gaussian(seed);
	 rdata[i]= tdata[i] ? 1+awgn_noise:-1+awgn_noise;
 }

}