channel_simulatormex.c

本程序利用改进的CHOW算法

#include "mex.h"
#include "mat.h"
#include <math.h>
#define mod_out plhs[0]
#define	mod_in prhs[0]
#define multipath prhs[1]
#define delaysprd prhs[2]

// function output_mod = channel_simulatormex(input_mod,multi_path,delay_spread);

//Pass in a modulated waveform (input_mod) to be alterred by a channel.
//Specify the type of channel to use (1==2-ray model 2==3-ray model)
//Also, specify the delay spread.
//returns modulated waveform with channel effects (output_mod)

// This function was written by me, Joe Williams, a Stanford EE Grad Student. It is used for my 
// EE359 project (Wireless Comm). You may use this code in whatever manner you want as long as
// you give me credit.

void mexFunction(int nlhs, 
                     mxArray *plhs[],
                     int nrhs, 
                     const mxArray *prhs[])
{
 
    double *output_mod,*input_mod,*output_temp;
	double length,multi_path;
    int j,delay_spread;

	input_mod = mxGetPr(mod_in);
	length = mxGetN(mod_in);
	delay_spread=mxGetScalar(delaysprd);
	multi_path=mxGetScalar(multipath);
    mod_out = mxCreateDoubleMatrix(1,length,mxREAL);
	output_mod = mxGetPr(mod_out);

	//multipath two ray model
	if(multi_path==1){
	  for(j=0;j<delay_spread;j++)
	    output_mod[j]=input_mod[j];
	  for(j=delay_spread;j<length;j++)
	    output_mod[j]=input_mod[j]+/*.5**/input_mod[j-delay_spread];
	}
	//multipath three ray model
	else if(multi_path==2){
	  for(j=0;j<delay_spread;j++)
	    output_mod[j]=input_mod[j];
	  for(j=delay_spread;j<length;j++)
	    output_mod[j]=input_mod[j]+/*.5**/input_mod[j-delay_spread/2]+/*.5**/input_mod[j-delay_spread];
	}
	//invalid multipath
	else{
	  for(j=0;j<length;j++)
  	    output_mod[j]=input_mod[j];
	}
}