errormodel80211.cc

ns2下用于802.11的无线传输模型的代码 增加了基于信噪比计算差错率等功能

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include "config.h"
#include "ErrorModel80211.h"

int ErrorModel80211::initialized_=0;

int ErrorModel80211::isShortPreamble_=0;

int ErrorModel80211::noise1_=-94;	//gotten from Orinoco card specification. Configurable.
int ErrorModel80211::noise2_=-91;
int ErrorModel80211::noise55_=-87;
int ErrorModel80211::noise11_=-82;

double ErrorModel80211::noiseW1_;       //In Watt.
double ErrorModel80211::noiseW2_;
double ErrorModel80211::noiseW55_;
double ErrorModel80211::noiseW11_;


double ErrorModel80211::ber_snr_[EM80211_NUM_MOD][EM80211_MAX_SNR+1];
double ErrorModel80211::preamble_succProb_[EM80211_MAX_SNR+1];
double ErrorModel80211::plcp_succProb_[EM80211_MAX_SNR+1];
double ErrorModel80211::ack_succProb_[EM80211_NUM_MOD][EM80211_MAX_SNR+1];
double ErrorModel80211::rts_succProb_[EM80211_NUM_MOD][EM80211_MAX_SNR+1];
double ErrorModel80211::cts_succProb_[EM80211_NUM_MOD][EM80211_MAX_SNR+1];


static class ErrorModel80211Class: public TclClass{
public: 
	ErrorModel80211Class() : TclClass("ErrorModel80211") {}
	TclObject* create(int argc, const char * const * argv)
	{
		return (new ErrorModel80211());
	}

	virtual void bind();
	virtual int method(int argc, const char * const * argv);
} class_errormodel80211;

void ErrorModel80211Class::bind()
{
	TclClass::bind();
	add_method("shortpreamble");
	add_method("noise1");
        add_method("noise2");
        add_method("noise55");
        add_method("noise11");
        add_method("LoadBerSnrFile");
}

int ErrorModel80211Class::method(int ac, const char* const * av)
{
	Tcl& tcl = Tcl::instance();
	int argc = ac - 2;
	const char* const * argv = av+2;
	if(argc == 2)
	{
		if(strcmp(argv[1],"shortpreamble")==0)
		{
			tcl.resultf("%d",ErrorModel80211::isShortPreamble_);
			return (TCL_OK);
		}else if(strcmp(argv[1],"noise1")==0)
                {
                        tcl.resultf("%d",ErrorModel80211::noise1_);
                        return (TCL_OK);
                }else if(strcmp(argv[1],"noise2")==0)
                {
                        tcl.resultf("%d",ErrorModel80211::noise2_);
                        return (TCL_OK);
                }else if(strcmp(argv[1],"noise55")==0)
                {
                        tcl.resultf("%d",ErrorModel80211::noise55_);
                        return (TCL_OK);
                }else if(strcmp(argv[1],"noise11")==0)
                {
                        tcl.resultf("%d",ErrorModel80211::noise11_);
                        return (TCL_OK);
                }

	}else if(argc == 3 )
	{
		if(strcmp(argv[1],"shortpreamble")==0)
		{
			ErrorModel80211::isShortPreamble_ = atoi(argv[2]);
			return (TCL_OK);
                }else if(strcmp(argv[1],"noise1")==0)
                {
                        ErrorModel80211::noise1_ = atoi(argv[2]);
			ErrorModel80211::noiseW1_ = pow(10, ErrorModel80211::noise1_/10)/1000;
                        return (TCL_OK);
                }else if(strcmp(argv[1],"noise2")==0)
                {
                        ErrorModel80211::noise2_ = atoi(argv[2]);
			ErrorModel80211::noiseW2_ = pow(10, ErrorModel80211::noise2_/10)/1000;
                        return (TCL_OK);
                }else if(strcmp(argv[1],"noise55")==0)
                {
                        ErrorModel80211::noise55_= atoi(argv[2]);
			ErrorModel80211::noiseW55_ = pow(10, ErrorModel80211::noise55_/10)/1000;
                        return (TCL_OK);
                }else if(strcmp(argv[1],"noise11")==0)
                {
                        ErrorModel80211::noise11_ = atoi(argv[2]);
			ErrorModel80211::noiseW11_ = pow(10, ErrorModel80211::noise11_/10)/1000;
                        return (TCL_OK);
                }else if(strcmp(argv[1],"LoadBerSnrFile")==0)
		{
			int rc;
			rc = ErrorModel80211::initialize(argv[2]);
			if(rc == TCL_OK) ErrorModel80211::initialized_=1;
			return rc;
		}
	}    
	
	return TclClass::method(ac,av);
}


int ErrorModel80211::initialize(const char* const& filename)
{
  FILE *fin;
  char line[100];
  int i,j,snr;
  int min,max;
  double d1,d2,d3,d4;


  i=0;j=0;
  min=EM80211_MAX_SNR;
  max=0;

  for(i=0;i<EM80211_NUM_MOD;i++)
    for(j=0;j<=EM80211_MAX_SNR;j++) ber_snr_[i][j]=-1;

  fin = fopen(filename,"r");
  if(fin==NULL) 
  {
	printf("%s  can not be opened! Please check the file name for ber_snr table. \n", filename);
	return(-1);
  }

  while(fgets(line,100,fin)!=NULL)
  {
    sscanf(line, "%d %lf %lf %lf %lf",&snr,&d1,&d2,&d3,&d4);
    if((snr>=0)&&(snr<=EM80211_MAX_SNR))
    {
      ber_snr_[0][snr]=d1;
      ber_snr_[1][snr]=d2;
      ber_snr_[2][snr]=d3;
      ber_snr_[3][snr]=d4;
      if(snr<min) min = snr;
      if(snr>max) max = snr;
    }
  }
  for(i=0;i<EM80211_NUM_MOD;i++)
  {
    ber_snr_[i][0] = 1;
    for(j=1;j<min;j++) ber_snr_[i][j] = ber_snr_[i][min];
    for(j=max+1;j<=EM80211_MAX_SNR;j++) ber_snr_[i][j] = ber_snr_[i][max];
  }
  fclose(fin);



  preCalculate();
  //printTables();

  printf("ErrorModel80211 is initialized successfully with %s \n",filename);

  initialized_ = 1;

  return TCL_OK;
}

void ErrorModel80211::preCalculate()
{
	int preamble_len;
	int plcp_mode;
	int i,j;

	if(isShortPreamble_) 
	{
		preamble_len = EM80211_SPREAMBLE_L;
		plcp_mode = EM80211_QPSK;
	} 
	else
	{
		preamble_len = EM80211_LPREAMBLE_L;
		plcp_mode=EM80211_BPSK;
	}

	for(i=0;i<=EM80211_MAX_SNR;i++)
	{
		preamble_succProb_[i] = pow((1-ber_snr_[0][i]),preamble_len);
		plcp_succProb_[i] = pow((1-ber_snr_[plcp_mode][i]),EM80211_PLCP_L);
	}

	for(i=0;i<=EM80211_MAX_SNR;i++)
	{
		for(j=0;j<EM80211_NUM_MOD;j++)
		{
		ack_succProb_[j][i]=pow((1-ber_snr_[j][i]),EM80211_ACK_L);
		rts_succProb_[j][i]=pow((1-ber_snr_[j][i]),EM80211_RTS_L);
		cts_succProb_[j][i]=pow((1-ber_snr_[j][i]),EM80211_CTS_L);
		}
	}

	return;
}


void ErrorModel80211::printTables()
{
	int i;

	printf("SNR  BER_mod1  BER_mod2  BER_mod3  BER_mod4....\n");
	for(i=0;i<=EM80211_MAX_SNR;i++)
	{
		printf("%d  %E  %E  %E  %E\n",i,ber_snr_[0][i],ber_snr_[1][i],ber_snr_[2][i],ber_snr_[3][i]);
	}

	printf("\n\n Preamble Success Probaility ....\n");
        for(i=0;i<=EM80211_MAX_SNR;i++)
        {
                printf("%d  %E\n",i,preamble_succProb_[i]);
        }

	printf("\n\n PLCP header success probability....\n");
        for(i=0;i<=EM80211_MAX_SNR;i++)
        {
                printf("%d  %E\n",i,plcp_succProb_[i]);
        }

	printf("\n\n Successful probalility of ACK frame without PHY header ....\n");
        for(i=0;i<=EM80211_MAX_SNR;i++)
        {
                printf("%d  %E  %E  %E  %E\n",i,ack_succProb_[0][i],ack_succProb_[1][i],ack_succProb_[2][i],ack_succProb_[3][i]);
        }

        printf("\n\n Successful probalility of RTS frame ....\n");
        for(i=0;i<=EM80211_MAX_SNR;i++)
        {
                printf("%d  %E  %E  %E  %E\n",i,rts_succProb_[0][i],rts_succProb_[1][i],rts_succProb_[2][i],rts_succProb_[3][i]);
        }

        printf("\n\n Successful probalility of CTS frame ....\n");
        for(i=0;i<=EM80211_MAX_SNR;i++)
        {
                printf("%d  %E  %E  %E  %E\n",i,cts_succProb_[0][i],cts_succProb_[1][i],cts_succProb_[2][i],cts_succProb_[3][i]);
        }

  
}


double ErrorModel80211::frameErrorRate( int frameType, double signal, double interference, double rate, int fullLen, int* snr_return)
{
	int mode,len;
	double fer;
	
	double noise;
	double ex_snr;
	int snr,snr_pre,snr_plcp;

	if(initialized_==0) return 0;

	if (rate < 1.5E6 ){ noise = noiseW1_; mode = EM80211_BPSK; }
	else if (rate < 2.5E6 ) { noise = noiseW2_; mode = EM80211_QPSK; }		else if (rate < 6.5E6 ) { noise = noiseW55_; mode = EM80211_CCK55; }
	else { noise = noiseW11_; mode = EM80211_CCK11; }

	ex_snr = 10*log10(signal/(noise+interference));
	if(ex_snr>0)
        {
                if(ex_snr > EM80211_MAX_SNR) snr = EM80211_MAX_SNR;
                else snr = (int) ex_snr;
        }
        else snr = 0;

	*snr_return = snr;


	ex_snr = 10*log10(signal/(noiseW1_+interference));
	if(ex_snr>0)
	{
		if(ex_snr > EM80211_MAX_SNR) snr_pre = EM80211_MAX_SNR;
		else snr_pre = (int) ex_snr;
	}
	else snr_pre = 0;

	if(!isShortPreamble_) snr_plcp = snr_pre;
	else
	{
		ex_snr = 10*log10(signal/(noiseW2_+interference));
		if(ex_snr>0)
		{
			if(ex_snr > EM80211_MAX_SNR) snr_plcp = EM80211_MAX_SNR;
			else snr_plcp = (int) ex_snr;
		}
		else snr_plcp = 0;
	}
	
	if(snr > EM80211_MAX_SNR) snr = EM80211_MAX_SNR;

	if(frameType == EM80211_ACK) return 1-preamble_succProb_[snr_pre]*plcp_succProb_[snr_plcp]*ack_succProb_[mode][snr];
	else if(frameType == EM80211_RTS) return 1-preamble_succProb_[snr_pre]*plcp_succProb_[snr_plcp]*rts_succProb_[mode][snr];
	else if(frameType == EM80211_CTS) return 1-preamble_succProb_[snr_pre]*plcp_succProb_[snr_plcp]*cts_succProb_[mode][snr];


	if(isShortPreamble_) 
		len = fullLen - (EM80211_SPREAMBLE_L+EM80211_PLCP_L)/8;
	else    len = fullLen - (EM80211_LPREAMBLE_L+EM80211_PLCP_L)/8;

	fer = 1-preamble_succProb_[snr_pre]*plcp_succProb_[snr_plcp]*pow((1-ber_snr_[mode][snr]),len*8);
	//printf("ErrorModel80211.cc --- SNR: %d, Length: %d, fer: %E\n",snr,fullLen, fer);
	 return fer;
}

double ErrorModel80211::ferBySnr(int frameType, int snr, int len, double rate)
{
	double fer;
	int snr_pre,snr_plcp,mode;

	if(initialized_ == 0) return 0;

	snr_pre = snr + snrDeltaBetweenRates(1E6,rate);

	if(rate < 1.5E6) mode = EM80211_BPSK;
	else if(rate <2.5E6) mode = EM80211_QPSK;
	else if(rate <6E6) mode = EM80211_CCK55;
	else mode = EM80211_CCK11;

        if(!isShortPreamble_) snr_plcp = snr_pre;
        else snr_plcp = snr_pre + (noise2_-noise1_);
                        
	if(snr_pre > EM80211_MAX_SNR) snr_pre = EM80211_MAX_SNR;
	if(snr_plcp >EM80211_MAX_SNR) snr_plcp = EM80211_MAX_SNR;
	if(snr > EM80211_MAX_SNR) snr = EM80211_MAX_SNR;

	if(frameType == EM80211_ACK) return 1-preamble_succProb_[snr_pre]*plcp_succProb_[snr_plcp]*ack_succProb_[mode][snr];
	else if(frameType == EM80211_RTS) return 1-preamble_succProb_[snr_pre]*plcp_succProb_[snr_plcp]*rts_succProb_[mode][snr];
	else if(frameType == EM80211_CTS) return 1-preamble_succProb_[snr_pre]*plcp_succProb_[snr_plcp]*cts_succProb_[mode][snr];


        fer = 1-preamble_succProb_[snr_pre]*plcp_succProb_[snr_plcp]*pow((1-ber_snr_[mode][snr]),len*8);
         return fer;
}

/*rate1 should always less than or equal to rate2*/
int ErrorModel80211::snrDeltaBetweenRates(double rate1, double rate2)
{

	if (rate1 < 1.5E6 )
	{
		if(rate2 <1.5E6) return 0;
		else if(rate2 <2.5E6) return (noise2_-noise1_);
		else if(rate2 < 6.5E6) return (noise55_-noise1_);
		else return (noise11_-noise2_);
	}else if(rate1 < 2.5E6)
	{
		if(rate2 <2.5E6) return 0;
		else if(rate2 <6.5E6) return (noise55_-noise2_);
		else return (noise11_-noise2_);
	}else if(rate1 <6.5E6)
	{
		if(rate2 <6.5E6) return 0;
		else return (noise11_-noise55_);	
	}
	else return 0;
}