chcomp.cpp

在vc上做的802.16d ofdm phy的仿真

#include "typedef.h"
#include "chcomp.h"

void chComp(Int16 *pChCompIn,
			Uint16 chCompLength,
			PhaseParam *pPhaseShift,
			ChannelEstResult *pPreambleChEstRes,
			Int16 *pChCompOut)
{
	Int16 i;
	Int16 freqOffsetCoarse;
	double freqOffsetFine;
	Int16 symbolCompIn[402]; 
	Int16 symbolCompFirst[402];
	Int16 symbolCompSecond[402];
	Int16 sinValue;
	Int16 cosValue;
	Int16 modChannel;
	Int16 compTap[2];
	Int16 modWidth = 11;//(averagebitwidth-1)
	Int16 bitWidth = 10;
	Int16 shiftFixPhrase = 14;
	Int16 shiftFreOffset = 15; // (16-1) mod of sine;
	//for test only

	for (i = 0; i < chCompLength - 55; i++)
	{
		pChCompOut[2*i] = pChCompIn[2*i+56];
		pChCompOut[2*i+1] = pChCompIn[2*i+57];
	}

/*	
	for (i = 0; i < chCompLength - 55; i++)
	{
		symbolCompIn[2*i] = pChCompIn[2*i+56];
		symbolCompIn[2*i+1] = pChCompIn[2*i+57];
	}
	
	for (i = 0; i < PREAMBLE_FREQ_FULL_SIZE; i++)
	{
		if (i == 100)
		{
			compTap[0] = 0;
			compTap[1] = 0;
		
		}
		else
		{
			modChannel = (pPreambleChEstRes[0].ChEstOut[2*i] * pPreambleChEstRes[0].ChEstOut[2*i]
						+ pPreambleChEstRes[0].ChEstOut[2*i+1] * pPreambleChEstRes[0].ChEstOut[2*i+1]) 
						>> modWidth;
			compTap[0] = (pPreambleChEstRes[0].ChEstOut[2*i] << modWidth) / modChannel ;
			compTap[1] = (pPreambleChEstRes[0].ChEstOut[2*i+1] << modWidth) / modChannel ;
		}
		
		pChCompOut[2*i] = (Int16)(((Int32)symbolCompIn[2*i] * compTap[0] 
								+ (Int32)symbolCompIn[2*i+1] * compTap[1]) >> bitWidth);
		pChCompOut[2*i+1] = (Int16)(((Int32)symbolCompIn[2*i+1] * compTap[0]
						 		- (Int32)symbolCompIn[2*i] * compTap[1]) >> bitWidth);
	}
	*/
	//去处信道响应
/*
	for (i = 0; i < PREAMBLE_FREQ_FULL_SIZE; i++)
	{

		symbolCompSecond[2*i] = (Int16)(((Int32)symbolCompFirst[2*i] * pPhaseShift[0].fixedPhase[0] 
							  + (Int32)symbolCompFirst[2*i+1] * pPhaseShift[0].fixedPhase[1])
								>> shiftFixPhrase);
		symbolCompSecond[2*i+1] = (Int16)(((Int32)symbolCompFirst[2*i+1] * pPhaseShift[0].fixedPhase[0] 
								- (Int32)symbolCompFirst[2*i] * pPhaseShift[0].fixedPhase[1])
								>> shiftFixPhrase);
	}
	for (i = 0; i < PREAMBLE_FREQ_FULL_SIZE; i++)
	{
		pChCompOut[2*i] = symbolCompSecond[2*i];
		pChCompOut[2*i+1] = symbolCompSecond[2*i+1];
	}

*/
	/*
	for (i = 0; i < PREAMBLE_FREQ_FULL_SIZE/2; i++)
	{
		freqOffsetCoarse =  pPhaseShift[0].freqIq * (100 - i) * 256 / (32767 * PI);
		freqOffsetFine = pPhaseShift[0].freqIq * (100-i) * 256 / (32767 * PI);
		if (freqOffsetCoarse == 0)
		{
			sinValue = freqOffsetFine * 32767 * PI / 256;
			cosValue = 32767 - ((sinValue * sinValue) >> 16);//cosx=1-0.5*x^2
		}
		else
		{
			sinValue = (Int16)(g_sineTable[freqOffsetCoarse] 
					+ (freqOffsetFine - freqOffsetCoarse) * g_sineTable[128-freqOffsetCoarse]);
			cosValue = (Int16)(g_sineTable[128-freqOffsetCoarse] 
					- (freqOffsetFine - freqOffsetCoarse) * g_sineTable[freqOffsetCoarse]);
		}
		
		pChCompOut[2*i] = (Int16)(((Int32)symbolCompSecond[2*i] * cosValue 
						- (Int32)symbolCompSecond[2*i+1] * sinValue)
							>> shiftFreOffset);
		pChCompOut[2*i+1] = (Int16)(((Int32)symbolCompSecond[2*i+1] * cosValue 
							+ (Int32)symbolCompSecond[2*i] * sinValue)
							>> shiftFreOffset);
		pChCompOut[2*(200-i)] = (Int16)(((Int32)symbolCompSecond[2*(200-i)] * cosValue 
							+ (Int32)symbolCompSecond[2*(200-i)+1] * sinValue)
								>> shiftFreOffset);
		pChCompOut[2*(200-i)+1] = (Int16)(((Int32)symbolCompSecond[2*(200-i)+1] * cosValue 
								- (Int32)symbolCompSecond[2*(200-i)] * sinValue)
								>> shiftFreOffset);
	}
	//去处信道的角偏移.
	pChCompOut[200] = symbolCompSecond[200];
	pChCompOut[201] = symbolCompSecond[201];
	*/
}