chtrack.cpp

在vc上做的802.16d ofdm phy的仿真

#include "typedef.h"

#include "chTrack.h"
#include "globalMacro.h"

void calculate(Int16 w, Int16 *sin, Int16 *cos)
{
	if (w == 0)
	{
		*sin = 0;
		*cos = 32767;
	}
	else
	{
		*sin = g_sineTable[w];
		*cos = g_sineTable[128 - w];
	}
}
	
void chTrack (Int16 *pRxFftOut,
			  Uint16 rxFftOutLength,
			  ChannelEstResult *pPreambleChEstRes,
			  PilotParam *pPilotParam,
			  PhaseParam *pPhaseShift)
{
	Int16 i;
	Uint8 wk;
	Uint8 outBit;
	Int16 symbolTrackLength = 201;
	Int16 symbolTrackIn[402];
	Int16 trackPilot[8*2];//remove chEst;
	Int16 tempI,tempQ;
	Int16  freqOffset;
	Int16  tanValue;
	Int16  angular;
	Int16  sinValue,cosValue;
	Int16  pilotOffsetSin[4],pilotOffsetCos[4];
	Int16  pilotOffset;
	Int8	resign, imsign, sign;

	Uint8  freqOffsetShift = 12;
	Uint8  fixPhaseShift = 15;
	Uint8  trackshift = 12;


	for (i = 0; i < rxFftOutLength - 55; i++)
	{
		symbolTrackIn[2*i] = pRxFftOut[2*i+56];
		symbolTrackIn[2*i+1] = pRxFftOut[2*i+57];
	}
	if (pPilotParam->ofdmSymIndex == 0)
	{
		pPilotParam->registers = pPilotParam->encodePoly;
	}
	
	wk = (pPilotParam->registers & 1);
	outBit = wk ^ ((pPilotParam->registers >>2) & 1);
	pPilotParam->registers >>= 1;
	outBit <<= 10;
	pPilotParam->registers |= outBit;
	pPilotParam->ofdmSymIndex ++;
	
	for (i = 0; i < 4; i++)
	{
		if (i == 1 || i == 3)
		{
			trackPilot[2*i] =  (Int16) (((Int32) symbolTrackIn[2*(12+25*i)] * pPreambleChEstRes[0].ChEstOut[2*(12+25*i)]
					 		+ (Int32) symbolTrackIn[2*(12+25*i)+1] * pPreambleChEstRes[0].ChEstOut[2*(12+25*i)+1]) >> trackshift) * (1-2*(~wk&1));
			trackPilot[2*i+1] = (Int16) (((Int32) symbolTrackIn[2*(12+25*i)+1] * pPreambleChEstRes[0].ChEstOut[2*(12+25*i)]
							- (Int32) symbolTrackIn[2*(12+25*i)] * pPreambleChEstRes[0].ChEstOut[2*(12+25*i)+1]) >> trackshift) * (1-2*(~wk&1));
		}
		else
		{
			trackPilot[2*i] =  (Int16) (((Int32) symbolTrackIn[2*(12+25*i)] * pPreambleChEstRes[0].ChEstOut[2*(12+25*i)]
					 		+ (Int32) symbolTrackIn[2*(12+25*i)+1] * pPreambleChEstRes[0].ChEstOut[2*(12+25*i)+1]) >> trackshift) * (1-2*(wk));
			trackPilot[2*i+1] = (Int16) (((Int32) symbolTrackIn[2*(12+25*i)+1] * pPreambleChEstRes[0].ChEstOut[2*(12+25*i)]
							- (Int32) symbolTrackIn[2*(12+25*i)] * pPreambleChEstRes[0].ChEstOut[2*(12+25*i)+1]) >> trackshift) * (1-2*(wk));	
		}	
	}	
	for (i = 4; i < 8; i++)
	{
		if (i == 4 || i == 5)
		{
			trackPilot[2*i] =  (Int16) (((Int32) symbolTrackIn[2*(13+25*i)] * pPreambleChEstRes[0].ChEstOut[2*(13+25*i)]
					 		+ (Int32) symbolTrackIn[2*(13+25*i)+1] * pPreambleChEstRes[0].ChEstOut[2*(13+25*i)+1]) >> trackshift) * (1-2*(~wk&1));
			trackPilot[2*i+1] = (Int16) (((Int32) symbolTrackIn[2*(13+25*i)+1] * pPreambleChEstRes[0].ChEstOut[2*(13+25*i)]
							- (Int32) symbolTrackIn[2*(13+25*i)] * pPreambleChEstRes[0].ChEstOut[2*(13+25*i)+1]) >> trackshift) * (1-2*(~wk&1));
		}
		else
		{
			trackPilot[2*i] =  (Int16) (((Int32) symbolTrackIn[2*(13+25*i)] * pPreambleChEstRes[0].ChEstOut[2*(13+25*i)]
					 		+ (Int32) symbolTrackIn[2*(13+25*i)+1] * pPreambleChEstRes[0].ChEstOut[2*(13+25*i)+1]) >> trackshift) * (1-2*(wk));
			trackPilot[2*i+1] = (Int16) (((Int32) symbolTrackIn[2*(13+25*i)+1] * pPreambleChEstRes[0].ChEstOut[2*(13+25*i)]
							- (Int32) symbolTrackIn[2*(13+25*i)] * pPreambleChEstRes[0].ChEstOut[2*(13+25*i)+1]) >> trackshift) * (1-2*(wk));	
		}	
	}		
	tempI = tempQ = 0;	
	for (i = 0; i < 3; i++)
	{
		tempI += (Int16) (((Int32) trackPilot[2*i] * trackPilot[2*(i+1)] 
				+ (Int32) trackPilot[2*i+1] * trackPilot[2*(i+1)+1]) 
				>> freqOffsetShift);
				 
		tempQ += (Int16) (((Int32) trackPilot[2*i] * trackPilot[2*(i+1)+1] 
				- (Int32) trackPilot[2*i+1] * trackPilot[2*(i+1)]) 
				>> freqOffsetShift);
				
	}
	for (i = 4; i < 7; i++)
	{
		tempI += (Int16) (((Int32) trackPilot[2*i] * trackPilot[2*(i+1)] 
				+ (Int32) trackPilot[2*i+1] * trackPilot[2*(i+1)+1]) >> freqOffsetShift);
				 
		tempQ += (Int16) (((Int32) trackPilot[2*i] * trackPilot[2*(i+1)+1] 
				- (Int32) trackPilot[2*i+1] * trackPilot[2*(i+1)]) >> freqOffsetShift);
	}
	
	resign = (tempI >= 0) ? 1 : -1;
	imsign = (tempQ >= 0) ? 1 : -1;
	sign = resign * imsign;
	tempI *= resign;
	tempQ *= imsign;
	if (tempQ <= tempI)//[0, pi/4);	
	{
		tanValue = tempQ * 128 / tempI;
		angular = g_atanCoarseTable[tanValue] + 
				((tempQ * 32767 / tempI - g_atanQuanLevelTable[tanValue]) * g_atanFineTable[tanValue] / 32767);
		pPhaseShift->freqIq = angular / 25;
	}
	else
	{
		tanValue = tempI * 128 / tempQ; 
		angular = g_atanCoarseTable[tanValue] + 
				( ( tempI * 32767 / tempQ - g_atanQuanLevelTable[tanValue]) * g_atanFineTable[tanValue] / 32767);
		pPhaseShift->freqIq = (51470 - angular) / 25; //pi/2~~~~51470 pi/4 ~~~~25735
	}
	freqOffset = pPhaseShift->freqIq * 256 / (32767 * PI);
	//the phase change angular frequency.
	calculate(freqOffset, &sinValue, &cosValue);
	pPhaseShift->fixedPhase[0] = pPhaseShift->fixedPhase[1] = 0;
	for (i = 0; i < 4; i++)
	{
		pilotOffset = (13 + 25 * (3 - i) ) * freqOffset;//subcarrier number 13,38,63,88  pilot
		calculate(pilotOffset, &pilotOffsetSin[i], &pilotOffsetCos[i]);
		
		pPhaseShift->fixedPhase[0] += (Int16) (((Int32) trackPilot[2*i] * pilotOffsetCos[i] 
									- (Int32) trackPilot[2*i+1] * pilotOffsetSin[i]
									+ (Int32) trackPilot[2*(7-i)] * pilotOffsetCos[i] 
									+ (Int32) trackPilot[2*(7-i)+1] * pilotOffsetSin[i]) 
									>> fixPhaseShift);
		
		pPhaseShift->fixedPhase[1] += (Int16) (((Int32) trackPilot[2*i+1] * pilotOffsetCos[i] 
									+ (Int32) trackPilot[2*i] * pilotOffsetSin[i]
									+ (Int32) trackPilot[2*(7-i)+1] * pilotOffsetCos[i] 
									- (Int32) trackPilot[2*(7-i)] * pilotOffsetSin[i]) 
									>> fixPhaseShift);
	}
}