/* awgn_c subroutine * additive white gaussian noise channel * with Box Muller Law method * for complex values * * Copyright (C) 2007-2011 Alan Layec * * This file is part of modnumlib. * * modnumlib is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * modnumlib is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with modnumlib; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * */ /* REVISION HISTORY : * $Log$ */ #include <math.h> #include <stdlib.h> /*pour RAND_MAX*/ #include "modnum_lib.h" /* awgn_c routine de calcul d'un canal à bruit blanc gaussien additif * (échantillons bruités par la méthode "Box Muller Law") * * Entrées : * n : dimension 1 des matrices d'entrée/sortie (scalaire) * m : dimension 2 des matrices d'entrée/sortie (scalaire) * sig : variance (scalaire) * mean : moyenne (scalaire) * u : matrice en entrée (double) * Sorties : * y : matrice en sortie (double) * * dépendances * math.h */ void awgn_c(int *n,int *m,double *sig,double *mean,double *u,double *y) { /*déclaration des variables*/ int i,l; double rand1, rand2; double rand_m; double ampl, phase; /*récupération de la valeur de RAND_MAX*/ rand_m=RAND_MAX; for(l=0;l<(*m);l++) { for(i=0;i<(*n);i++) { /*calcul rand1*/ rand1=rand()/rand_m; /*test rand1*/ while((rand1<=0)||(rand1>=1)) rand1=rand()/rand_m; /*calcul rand2*/ rand2=rand()/rand_m; /*test rand2*/ while((rand2<=0)||(rand2>=1)) rand2=rand()/rand_m; /*Calcul amplitude et phase*/ ampl=(*sig)*sqrt(2*-log(rand1)); phase=2*M_PI*rand2; /*Calcul y*/ y[(*n)*l+i]=u[(*n)*l+i]+(*mean)+ampl*cos(phase); } } return; } void awgniq_c(int *n,int *m,double *sig,double *mean,\ double *u_i,double *u_q,\ double *y_i,double *y_q) { /*déclaration des variables*/ int i,l; double rand1, rand2; double rand_m; double ampl, phase; /*récupération de la valeur de RAND_MAX*/ rand_m=RAND_MAX; for(l=0;l<(*m);l++) { for(i=0;i<(*n);i++) { /*calcul rand1*/ rand1=rand()/rand_m; /*test rand1*/ while((rand1<=0)||(rand1>=1)) rand1=rand()/rand_m; /*calcul rand2*/ rand2=rand()/rand_m; /*test rand2*/ while((rand2<=0)||(rand2>=1)) rand2=rand()/rand_m; /*Calcul amplitude et phase*/ ampl=(*sig)*sqrt(-log(rand1)); phase=2*M_PI*rand2; /*Calcul y_c et y_q*/ y_i[(*n)*l+i]=u_i[(*n)*l+i]+(*mean)+ampl*cos(phase); y_q[(*n)*l+i]=u_q[(*n)*l+i]+(*mean)+ampl*sin(phase); } } return; } void awgni_c(int *n,int *m,double *sig,double *mean,int *u,double *y) { /*déclaration des variables*/ int i,l; double rand1, rand2; double rand_m; double ampl, phase; /*récupération de la valeur de RAND_MAX*/ rand_m=RAND_MAX; for(l=0;l<(*m);l++) { for(i=0;i<(*n);i++) { /*calcul rand1*/ rand1=rand()/rand_m; /*test rand1*/ while((rand1<=0)||(rand1>=1)) rand1=rand()/rand_m; /*calcul rand2*/ rand2=rand()/rand_m; /*test rand2*/ while((rand2<=0)||(rand2>=1)) rand2=rand()/rand_m; /*Calcul amplitude et phase*/ ampl=(*sig)*sqrt(2*-log(rand1)); phase=2*M_PI*rand2; /*Calcul y*/ y[(*n)*l+i]=(double)(u[(*n)*l+i])+(*mean)+ampl*cos(phase); } } return; } void awgniqi_c(int *n,int *m,double *sig,double *mean,\ int *u_i,int *u_q,\ double *y_i,double *y_q) { /*déclaration des variables*/ int i,l; double rand1, rand2; double rand_m; double ampl, phase; /*récupération de la valeur de RAND_MAX*/ rand_m=RAND_MAX; for(l=0;l<(*m);l++) { for(i=0;i<(*n);i++) { /*calcul rand1*/ rand1=rand()/rand_m; /*test rand1*/ while((rand1<=0)||(rand1>=1)) rand1=rand()/rand_m; /*calcul rand2*/ rand2=rand()/rand_m; /*test rand2*/ while((rand2<=0)||(rand2>=1)) rand2=rand()/rand_m; /*Calcul amplitude et phase*/ ampl=(*sig)*sqrt(-log(rand1)); phase=2*M_PI*rand2; /*Calcul y_i et y_q*/ y_i[(*n)*l+i]=(double)(u_i[(*n)*l+i])+(*mean)+ampl*cos(phase); y_q[(*n)*l+i]=(double)(u_q[(*n)*l+i])+(*mean)+ampl*sin(phase); } } return; }