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Commit 6b83d9e0 authored by Roberto Louro Magueta's avatar Roberto Louro Magueta Committed by luis_pereira87
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Compute normalization channel factor

parent 9b594ff3
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Showing with 96 additions and 7 deletions
openair1/SIMULATION/TOOLS/random_channel.c
View file @ 6b83d9e0
......@@ -36,6 +36,7 @@
//#define DEBUG_CH
//#define DEBUG_CH_POWER
#include "assertions.h"
......@@ -450,6 +451,71 @@ void tdlModel(int tdl_paths, double *tdl_delays, double *tdl_amps_dB, double DS
}
}
double get_normalization_ch_factor(channel_desc_t *desc)
{
if (!(desc->channel_length > 1 && desc->modelid >= TDL_A && desc->modelid <= TDL_E)) {
return 1.0;
}
uint16_t N_average = 1000;
double accumulated_ch_power = 0;
struct complexd a[desc->nb_taps][desc->nb_tx * desc->nb_rx];
struct complexd anew[desc->nb_tx * desc->nb_rx];
struct complexd acorr[desc->nb_tx * desc->nb_rx];
for (int n = 1; n <= N_average; n++) {
for (int l = 0; l < (int)desc->nb_taps; l++) {
for (int aarx = 0; aarx < desc->nb_rx; aarx++) {
for (int aatx = 0; aatx < desc->nb_tx; aatx++) {
anew[aarx + (aatx * desc->nb_rx)].r = sqrt(desc->ricean_factor * desc->amps[l] / 2) * gaussdouble(0.0, 1.0);
anew[aarx + (aatx * desc->nb_rx)].i = sqrt(desc->ricean_factor * desc->amps[l] / 2) * gaussdouble(0.0, 1.0);
if ((l == 0) && (desc->ricean_factor != 1.0)) {
anew[aarx + (aatx * desc->nb_rx)].r += sqrt((1.0 - desc->ricean_factor) / 2);
anew[aarx + (aatx * desc->nb_rx)].i += sqrt((1.0 - desc->ricean_factor) / 2);
}
} // for (int aatx = 0; aatx < desc->nb_tx; aatx++)
} // for (int aarx = 0; aarx < desc->nb_rx; aarx++)
// Apply correlation matrix
bzero(acorr, desc->nb_tx * desc->nb_rx * sizeof(struct complexd));
for (int aatx = 0; aatx < desc->nb_tx; aatx++) {
for (int aarx = 0; aarx < desc->nb_rx; aarx++) {
cblas_zaxpy(desc->nb_tx * desc->nb_rx,
(void *)&anew[aarx + (aatx * desc->nb_rx)],
(void *)desc->R_sqrt[aarx + (aatx * desc->nb_rx)],
1,
(void *)acorr,
1);
} // for (int aarx = 0; aarx < desc->nb_rx; aarx++)
} // for (int aatx = 0; aatx < desc->nb_tx; aatx++)
cblas_zcopy(desc->nb_tx * desc->nb_rx, (void *)acorr, 1, (void *)a[l], 1);
} // for (int l = 0; l < (int)desc->nb_taps; l++)
for (int aarx = 0; aarx < desc->nb_rx; aarx++) {
for (int aatx = 0; aatx < desc->nb_tx; aatx++) {
for (int k = 0; k < (int)desc->channel_length; k++) {
double ch_r = 0.0;
double ch_i = 0.0;
double s = 0.0;
for (int l = 0; l < desc->nb_taps; l++) {
if ((k - (desc->delays[l] * desc->sampling_rate) - desc->channel_offset) == 0) {
s = 1.0;
} else {
s = sin(M_PI * (k - (desc->delays[l] * desc->sampling_rate) - desc->channel_offset)) /
(M_PI * (k - (desc->delays[l] * desc->sampling_rate) - desc->channel_offset));
}
ch_r += s * a[l][aarx + (aatx * desc->nb_rx)].r;
ch_i += s * a[l][aarx + (aatx * desc->nb_rx)].i;
} // for (int l = 0; l < desc->nb_taps; l++)
accumulated_ch_power += (ch_r * ch_r + ch_i * ch_i);
} // for (int k = 0; k < (int)desc->channel_length; k++)
} // for (int aatx = 0; aatx < desc->nb_tx; aatx++)
} // for (int aarx = 0; aarx < desc->nb_rx; aarx++)
}
return sqrt((N_average * desc->nb_tx * desc->nb_rx) / accumulated_ch_power);
}
channel_desc_t *new_channel_desc_scm(uint8_t nb_tx,
uint8_t nb_rx,
SCM_t channel_model,
......@@ -491,6 +557,7 @@ channel_desc_t *new_channel_desc_scm(uint8_t nb_tx,
chan_desc->first_run = 1;
chan_desc->ip = 0.0;
chan_desc->noise_power_dB = noise_power_dB;
chan_desc->normalization_ch_factor = 1.0;
LOG_I(OCM,"Channel Model (inside of new_channel_desc_scm)=%d\n\n", channel_model);
int tdl_paths=0;
double *tdl_amps_dB;
......@@ -1540,6 +1607,8 @@ channel_desc_t *new_channel_desc_scm(uint8_t nb_tx,
return(NULL);
}
chan_desc->normalization_ch_factor = get_normalization_ch_factor(chan_desc);
LOG_D(OCM,"[CHANNEL] RF %f\n",chan_desc->ricean_factor);
for (i=0; i<chan_desc->nb_taps; i++)
......@@ -1608,6 +1677,11 @@ void set_channeldesc_name(channel_desc_t *cdesc,char *modelname) {
cdesc->model_name=strdup(modelname);
}
#ifdef DEBUG_CH_POWER
double accumulated_ch_power = 0;
int ch_power_count = 0;
#endif
int random_channel(channel_desc_t *desc, uint8_t abstraction_flag) {
double s;
int i,k,l,aarx,aatx;
......@@ -1637,8 +1711,9 @@ int random_channel(channel_desc_t *desc, uint8_t abstraction_flag) {
for (i=0; i<(int)desc->nb_taps; i++) {
for (aarx=0; aarx<desc->nb_rx; aarx++) {
for (aatx=0; aatx<desc->nb_tx; aatx++) {
anew[aarx+(aatx*desc->nb_rx)].r = sqrt(desc->ricean_factor*desc->amps[i]/2) * gaussdouble(0.0,1.0);
anew[aarx+(aatx*desc->nb_rx)].i = sqrt(desc->ricean_factor*desc->amps[i]/2) * gaussdouble(0.0,1.0);
anew[aarx + (aatx * desc->nb_rx)].r = sqrt(desc->ricean_factor * desc->amps[i] / 2) * gaussdouble(0.0, 1.0) * desc->normalization_ch_factor;
anew[aarx + (aatx * desc->nb_rx)].i = sqrt(desc->ricean_factor * desc->amps[i] / 2) * gaussdouble(0.0, 1.0) * desc->normalization_ch_factor;
if ((i==0) && (desc->ricean_factor != 1.0)) {
if (desc->random_aoa==1) {
......@@ -1648,10 +1723,10 @@ int random_channel(channel_desc_t *desc, uint8_t abstraction_flag) {
// this assumes that both RX and TX have linear antenna arrays with lambda/2 antenna spacing.
// Furhter it is assumed that the arrays are parallel to each other and that they are far enough apart so
// that we can safely assume plane wave propagation.
phase.r = cos(M_PI*((aarx-aatx)*sin(desc->aoa)));
phase.i = sin(M_PI*((aarx-aatx)*sin(desc->aoa)));
anew[aarx+(aatx*desc->nb_rx)].r += phase.r * sqrt(1.0-desc->ricean_factor);
anew[aarx+(aatx*desc->nb_rx)].i += phase.i * sqrt(1.0-desc->ricean_factor);
phase.r = cos(M_PI * ((aarx - aatx) * sin(desc->aoa)));
phase.i = sin(M_PI * ((aarx - aatx) * sin(desc->aoa)));
anew[aarx + (aatx * desc->nb_rx)].r += phase.r * sqrt(1.0 - desc->ricean_factor) * desc->normalization_ch_factor;
anew[aarx + (aatx * desc->nb_rx)].i += phase.i * sqrt(1.0 - desc->ricean_factor) * desc->normalization_ch_factor;
}
#ifdef DEBUG_CH
......@@ -1672,6 +1747,7 @@ int random_channel(channel_desc_t *desc, uint8_t abstraction_flag) {
*/
//apply correlation matrix
//compute acorr = R_sqrt[i] * anew
bzero(acorr, desc->nb_tx * desc->nb_rx * sizeof(struct complexd));
if (desc->modelid >= TDL_A && desc->modelid <= TDL_E) {
for (aatx = 0; aatx < desc->nb_tx; aatx++) {
for (aarx=0; aarx<desc->nb_rx; aarx++) {
......@@ -1684,7 +1760,6 @@ int random_channel(channel_desc_t *desc, uint8_t abstraction_flag) {
}
}
} else {
bzero(acorr,desc->nb_tx*desc->nb_rx*sizeof(struct complexd));
cblas_zaxpy(desc->nb_tx*desc->nb_rx, (void *) desc->R_sqrt[i/3], (void *) anew, 1, (void *) acorr, 1);
}
......@@ -1765,14 +1840,26 @@ int random_channel(channel_desc_t *desc, uint8_t abstraction_flag) {
// printf("l %d : desc->ch.x %f, s %e, delay %f\n",l,desc->a[l][aarx+(aatx*desc->nb_rx)].x,s,desc->delays[l]);
} //nb_taps
#ifdef DEBUG_CH_POWER
accumulated_ch_power += (desc->ch[aarx + (aatx * desc->nb_rx)][k].r * desc->ch[aarx + (aatx * desc->nb_rx)][k].r +
desc->ch[aarx + (aatx * desc->nb_rx)][k].i * desc->ch[aarx + (aatx * desc->nb_rx)][k].i);
#endif
#ifdef DEBUG_CH
printf("(%d,%d,%d)->(%e,%e)\n",k,aarx,aatx,desc->ch[aarx+(aatx*desc->nb_rx)][k].r,desc->ch[aarx+(aatx*desc->nb_rx)][k].i);
#endif
} //channel_length
#ifdef DEBUG_CH_POWER
ch_power_count++;
#endif
}
} //aatx
} //aarx
#ifdef DEBUG_CH_POWER
printf("(%5i) Average channel power = %f\n", ch_power_count, accumulated_ch_power / ch_power_count);
#endif
stop_meas(&desc->interp_time);
}
......
openair1/SIMULATION/TOOLS/sim.h
View file @ 6b83d9e0
......@@ -66,6 +66,8 @@ typedef struct {
uint8_t nb_taps;
///linear amplitudes of taps
double *amps;
///normalization channel factor
double normalization_ch_factor;
///Delays of the taps in mus. length(delays)=nb_taps. Has to be between 0 and Td.
double *delays;
///length of impulse response. should be set to 11+2*bw*t_max
......
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