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openairinterface5g/openair1/SIMULATION/TOOLS/phase_noise.c
T

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C

/*
* Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The OpenAirInterface Software Alliance licenses this file to You under
* the OAI Public License, Version 1.1 (the "License"); you may not use this file
* except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.openairinterface.org/?page_id=698
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*-------------------------------------------------------------------------------
* For more information about the OpenAirInterface (OAI) Software Alliance:
* contact@openairinterface.org
*/
#include <math.h>
#include "sim.h"
static uint16_t LUTSin[ResolSinCos+1];
/* linear phase noise model */
void phase_noise(double ts, int16_t * InRe, int16_t * InIm)
{
static uint64_t i=0;
int32_t x=0 ,y=0;
double fd = 300;//0.01*30000
int16_t SinValue = 0, CosValue= 0;
double IdxDouble = (double)(i*fd * ts * ResolSinCos * 4);
int16_t IdxModulo = ((int32_t)(IdxDouble>0 ? IdxDouble+0.5 : IdxDouble-0.5)) % (ResolSinCos*4);
IdxModulo = IdxModulo<0 ? IdxModulo+ResolSinCos*4 : IdxModulo;
if(IdxModulo<2*ResolSinCos) {//< 2 check for 1st and 2nd
if(IdxModulo < ResolSinCos) {// 1st Quadrant
SinValue = LUTSin[IdxModulo];
CosValue = LUTSin[ResolSinCos-IdxModulo];
}
else {// 2nd Quadrant
SinValue = LUTSin[2*ResolSinCos-IdxModulo];
CosValue = -LUTSin[IdxModulo-ResolSinCos];
}
}
else {// 3rd and 4th Quadrant
if(IdxModulo < 3*ResolSinCos) {// 3rd Quadrant
SinValue = -LUTSin[IdxModulo-2*ResolSinCos];
CosValue = -LUTSin[3*ResolSinCos-IdxModulo];
}
else {//4th Quadrant
SinValue = -LUTSin[4*ResolSinCos-IdxModulo];
CosValue = LUTSin[IdxModulo-3*ResolSinCos];
}
}
x = ( ((int32_t)InRe[0] * CosValue) - ((int32_t)InIm[0] * SinValue ));
y = ( ((int32_t)InIm[0] * CosValue) + ((int32_t)InRe[0] * SinValue ));
InRe[0]= (int16_t)(x>>14);
InIm[0]= (int16_t)(y>>14);
i++;
}
/* Initialisation function for SIN table values */
void InitSinLUT( void ) {
for ( int i=0; i<(ResolSinCos+1); i++ ) {
LUTSin[i] = sin((double)(M_PI*i)/(2*ResolSinCos)) * (1<<14); //Format: Q14
}
}