|
|
|
|
@ -40,11 +40,32 @@
|
|
|
|
|
#include "srslte/utils/vector.h"
|
|
|
|
|
#include "srslte/utils/convolution.h"
|
|
|
|
|
|
|
|
|
|
#define CHEST_RS_AVERAGE_TIME 2
|
|
|
|
|
#define CHEST_RS_AVERAGE_FREQ 3
|
|
|
|
|
|
|
|
|
|
#define NOISE_POWER_METHOD 1 // 0: Difference between noisy received and noiseless; 1: power of empty subcarriers
|
|
|
|
|
|
|
|
|
|
#define DEFAULT_FILTER_FREQ_LEN 11 // Must be odd
|
|
|
|
|
#define DEFAULT_FILTER_TIME_LEN 3
|
|
|
|
|
|
|
|
|
|
static void init_default_filters(srslte_chest_dl_t *q) {
|
|
|
|
|
|
|
|
|
|
float f[DEFAULT_FILTER_FREQ_LEN];
|
|
|
|
|
float t[DEFAULT_FILTER_TIME_LEN];
|
|
|
|
|
|
|
|
|
|
for (int i=0;i<DEFAULT_FILTER_FREQ_LEN/2+1;i++) {
|
|
|
|
|
f[i] = 1+i;
|
|
|
|
|
f[DEFAULT_FILTER_FREQ_LEN-i-1] = 1+i;
|
|
|
|
|
}
|
|
|
|
|
float norm = srslte_vec_acc_ff(f, DEFAULT_FILTER_FREQ_LEN);
|
|
|
|
|
srslte_vec_sc_prod_fff(f, 1.0/norm, f, DEFAULT_FILTER_FREQ_LEN);
|
|
|
|
|
srslte_chest_dl_set_filter_freq(q, f, DEFAULT_FILTER_FREQ_LEN);
|
|
|
|
|
|
|
|
|
|
for (int i=0;i<DEFAULT_FILTER_TIME_LEN/2+1;i++) {
|
|
|
|
|
t[i] = 1+i;
|
|
|
|
|
t[DEFAULT_FILTER_TIME_LEN-i-1] = 1+i;
|
|
|
|
|
}
|
|
|
|
|
norm = srslte_vec_acc_ff(t, DEFAULT_FILTER_TIME_LEN);
|
|
|
|
|
srslte_vec_sc_prod_fff(t, 1.0/norm, t, DEFAULT_FILTER_TIME_LEN);
|
|
|
|
|
srslte_chest_dl_set_filter_time(q, t, DEFAULT_FILTER_TIME_LEN);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/** 3GPP LTE Downlink channel estimator and equalizer.
|
|
|
|
|
* Estimates the channel in the resource elements transmitting references and interpolates for the rest
|
|
|
|
|
@ -69,42 +90,28 @@ int srslte_chest_dl_init(srslte_chest_dl_t *q, srslte_cell_t cell)
|
|
|
|
|
goto clean_exit;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
q->tmp_freqavg = srslte_vec_malloc(sizeof(cf_t) * SRSLTE_REFSIGNAL_MAX_NUM_SF(cell.nof_prb));
|
|
|
|
|
q->tmp_freqavg = srslte_vec_malloc(sizeof(cf_t) * SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp));
|
|
|
|
|
if (!q->tmp_freqavg) {
|
|
|
|
|
perror("malloc");
|
|
|
|
|
goto clean_exit;
|
|
|
|
|
}
|
|
|
|
|
q->tmp_noise = srslte_vec_malloc(sizeof(cf_t) * 2 * SRSLTE_REFSIGNAL_MAX_NUM_SF(cell.nof_prb));
|
|
|
|
|
q->tmp_noise = srslte_vec_malloc(sizeof(cf_t) * SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp));
|
|
|
|
|
if (!q->tmp_noise) {
|
|
|
|
|
perror("malloc");
|
|
|
|
|
goto clean_exit;
|
|
|
|
|
}
|
|
|
|
|
for (int i=0;i<SRSLTE_CHEST_MAX_FILTER_TIME_LEN;i++) {
|
|
|
|
|
q->tmp_timeavg[i] = srslte_vec_malloc(sizeof(cf_t) * 2*cell.nof_prb);
|
|
|
|
|
if (!q->tmp_timeavg[i]) {
|
|
|
|
|
perror("malloc");
|
|
|
|
|
goto clean_exit;
|
|
|
|
|
}
|
|
|
|
|
bzero(q->tmp_timeavg[i], sizeof(cf_t) * 2*cell.nof_prb);
|
|
|
|
|
}
|
|
|
|
|
q->tmp_timeavg_mult = srslte_vec_malloc(sizeof(cf_t) * 2*cell.nof_prb);
|
|
|
|
|
q->tmp_timeavg_mult = srslte_vec_malloc(sizeof(cf_t) * 12*cell.nof_prb);
|
|
|
|
|
if (!q->tmp_timeavg_mult) {
|
|
|
|
|
perror("malloc");
|
|
|
|
|
goto clean_exit;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
for (int i=0;i<cell.nof_ports;i++) {
|
|
|
|
|
q->pilot_estimates[i] = srslte_vec_malloc(sizeof(cf_t) * SRSLTE_REFSIGNAL_NUM_SF(cell.nof_prb, i));
|
|
|
|
|
q->pilot_estimates[i] = srslte_vec_malloc(2*sizeof(cf_t) * SRSLTE_REFSIGNAL_NUM_SF(cell.nof_prb, i));
|
|
|
|
|
if (!q->pilot_estimates[i]) {
|
|
|
|
|
perror("malloc");
|
|
|
|
|
goto clean_exit;
|
|
|
|
|
}
|
|
|
|
|
// FIXME: There's an invalid read during rsrp estimation for this buffer
|
|
|
|
|
q->pilot_estimates_average[i] = srslte_vec_malloc(2 * sizeof(cf_t) * SRSLTE_REFSIGNAL_NUM_SF(cell.nof_prb, i));
|
|
|
|
|
if (!q->pilot_estimates_average[i]) {
|
|
|
|
|
perror("malloc");
|
|
|
|
|
goto clean_exit;
|
|
|
|
|
}
|
|
|
|
|
q->pilot_recv_signal[i] = srslte_vec_malloc(sizeof(cf_t) * SRSLTE_REFSIGNAL_NUM_SF(cell.nof_prb, i));
|
|
|
|
|
if (!q->pilot_recv_signal[i]) {
|
|
|
|
|
perror("malloc");
|
|
|
|
|
@ -122,15 +129,7 @@ int srslte_chest_dl_init(srslte_chest_dl_t *q, srslte_cell_t cell)
|
|
|
|
|
goto clean_exit;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Set default time/freq filters */
|
|
|
|
|
//float f[3]={0.2, 0.6, 0.2};
|
|
|
|
|
//srslte_chest_dl_set_filter_freq(q, f, 3);
|
|
|
|
|
|
|
|
|
|
float f[9]={0.025, 0.075, 0.05, 0.15, 0.4, 0.15, 0.05, 0.075, 0.025};
|
|
|
|
|
srslte_chest_dl_set_filter_freq(q, f, 9);
|
|
|
|
|
|
|
|
|
|
//srslte_chest_dl_set_filter_time_ema(q, 0.8);
|
|
|
|
|
|
|
|
|
|
init_default_filters(q);
|
|
|
|
|
q->cell = cell;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
@ -153,11 +152,6 @@ void srslte_chest_dl_free(srslte_chest_dl_t *q)
|
|
|
|
|
if (q->tmp_noise) {
|
|
|
|
|
free(q->tmp_noise);
|
|
|
|
|
}
|
|
|
|
|
for (int i=0;i<SRSLTE_CHEST_MAX_FILTER_TIME_LEN;i++) {
|
|
|
|
|
if (q->tmp_timeavg[i]) {
|
|
|
|
|
free(q->tmp_timeavg[i]);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
if (q->tmp_timeavg_mult) {
|
|
|
|
|
free(q->tmp_timeavg_mult);
|
|
|
|
|
}
|
|
|
|
|
@ -168,9 +162,6 @@ void srslte_chest_dl_free(srslte_chest_dl_t *q)
|
|
|
|
|
if (q->pilot_estimates[i]) {
|
|
|
|
|
free(q->pilot_estimates[i]);
|
|
|
|
|
}
|
|
|
|
|
if (q->pilot_estimates_average[i]) {
|
|
|
|
|
free(q->pilot_estimates_average[i]);
|
|
|
|
|
}
|
|
|
|
|
if (q->pilot_recv_signal[i]) {
|
|
|
|
|
free(q->pilot_recv_signal[i]);
|
|
|
|
|
}
|
|
|
|
|
@ -209,14 +200,11 @@ int srslte_chest_dl_set_filter_time(srslte_chest_dl_t *q, float *filter, uint32_
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
#if NOISE_POWER_METHOD==0
|
|
|
|
|
|
|
|
|
|
/* Uses the difference between the averaged and non-averaged pilot estimates */
|
|
|
|
|
static float estimate_noise_port(srslte_chest_dl_t *q, uint32_t port_id, cf_t *avg_pilots) {
|
|
|
|
|
static float estimate_noise_port(srslte_chest_dl_t *q, cf_t *average, cf_t *ce, uint32_t len) {
|
|
|
|
|
/* Use difference between averaged and noisy LS pilot estimates */
|
|
|
|
|
srslte_vec_sub_ccc(avg_pilots, q->pilot_estimates[port_id],
|
|
|
|
|
q->tmp_noise, SRSLTE_REFSIGNAL_NUM_SF(q->cell.nof_prb, port_id));
|
|
|
|
|
|
|
|
|
|
return srslte_vec_avg_power_cf(q->tmp_noise, SRSLTE_REFSIGNAL_NUM_SF(q->cell.nof_prb, port_id));
|
|
|
|
|
srslte_vec_sub_ccc(average, ce, q->tmp_noise, len);
|
|
|
|
|
return srslte_vec_avg_power_cf(q->tmp_noise, len);
|
|
|
|
|
}
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
@ -236,97 +224,52 @@ static float estimate_noise_port(srslte_chest_dl_t *q, cf_t *input) {
|
|
|
|
|
}
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
#define pilot_est(idx) q->pilot_estimates[port_id][SRSLTE_REFSIGNAL_PILOT_IDX(idx,l,q->cell)]
|
|
|
|
|
#define pilot_avg(idx) q->pilot_estimates_average[port_id][SRSLTE_REFSIGNAL_PILOT_IDX(idx,l,q->cell)]
|
|
|
|
|
#define pilot_tmp(idx) q->tmp_freqavg[SRSLTE_REFSIGNAL_PILOT_IDX(idx,l,q->cell)]
|
|
|
|
|
|
|
|
|
|
static void average_pilots(srslte_chest_dl_t *q, uint32_t port_id)
|
|
|
|
|
static void average_estimates(srslte_chest_dl_t *q, cf_t *ce, uint32_t port_id)
|
|
|
|
|
{
|
|
|
|
|
int nref=2*q->cell.nof_prb;
|
|
|
|
|
int nref=12*q->cell.nof_prb;
|
|
|
|
|
uint32_t l, i;
|
|
|
|
|
|
|
|
|
|
/* For each symbol with pilots in a slot */
|
|
|
|
|
for (l=0;l<srslte_refsignal_cs_nof_symbols(port_id);l++) {
|
|
|
|
|
for (l=0;l<SRSLTE_CP_NSYMB(q->cell.cp);l++) {
|
|
|
|
|
if (q->filter_freq_len > 0) {
|
|
|
|
|
/* Filter pilot estimates in frequency */
|
|
|
|
|
srslte_conv_same_cf(&pilot_est(0), q->filter_freq, &pilot_tmp(0), nref, q->filter_freq_len);
|
|
|
|
|
|
|
|
|
|
/* Adjust extremes using linear interpolation */
|
|
|
|
|
|
|
|
|
|
pilot_tmp(0) += srslte_interp_linear_onesample(pilot_est(1), pilot_est(0))
|
|
|
|
|
* q->filter_freq[q->filter_freq_len/2-1]*1.2;
|
|
|
|
|
pilot_tmp(nref-1) += srslte_interp_linear_onesample(pilot_est(nref-2), pilot_est(nref-1))
|
|
|
|
|
* q->filter_freq[q->filter_freq_len/2+1]*1.2;
|
|
|
|
|
srslte_conv_same_cf(&ce[l*12*q->cell.nof_prb], q->filter_freq, &q->tmp_freqavg[l*12*q->cell.nof_prb], nref, q->filter_freq_len);
|
|
|
|
|
} else {
|
|
|
|
|
memcpy(&pilot_tmp(0), &pilot_est(0), nref * sizeof(cf_t));
|
|
|
|
|
memcpy(&q->tmp_freqavg[l*12*q->cell.nof_prb], &ce[l*12*q->cell.nof_prb], nref * sizeof(cf_t));
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
#if NOISE_POWER_METHOD==0
|
|
|
|
|
q->noise_estimate[port_id] = estimate_noise_port(q, port_id, q->tmp_freqavg);
|
|
|
|
|
q->noise_estimate[port_id] = estimate_noise_port(q, q->tmp_freqavg, ce,
|
|
|
|
|
SRSLTE_SF_LEN_RE(q->cell.nof_prb, q->cell.cp));
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
//#define EMA_VEC
|
|
|
|
|
|
|
|
|
|
/* Filter with Exponential moving average (IIR) */
|
|
|
|
|
if (q->filter_time_ema > 0) {
|
|
|
|
|
#ifdef EMA_VEC
|
|
|
|
|
srslte_vec_ema_filter(&q->tmp_freqavg[0],
|
|
|
|
|
&q->pilot_estimates_average[port_id][2*q->cell.nof_prb*srslte_refsignal_cs_nof_symbols(port_id)],
|
|
|
|
|
&q->pilot_estimates_average[port_id][0],
|
|
|
|
|
q->filter_time_ema,
|
|
|
|
|
nref);
|
|
|
|
|
for (l=1;l<srslte_refsignal_cs_nof_symbols(port_id);l++) {
|
|
|
|
|
srslte_vec_ema_filter(&q->tmp_freqavg[2*q->cell.nof_prb*l],
|
|
|
|
|
&q->pilot_estimates_average[port_id][2*q->cell.nof_prb*(l-1)],
|
|
|
|
|
&q->pilot_estimates_average[port_id][2*q->cell.nof_prb*l],
|
|
|
|
|
q->filter_time_ema,
|
|
|
|
|
nref);
|
|
|
|
|
}
|
|
|
|
|
#else
|
|
|
|
|
for (i=0;i<nref;i++) {
|
|
|
|
|
l=0;
|
|
|
|
|
pilot_avg(i) = SRSLTE_VEC_EMA(pilot_tmp(i), q->pilot_estimates_average[port_id][
|
|
|
|
|
SRSLTE_REFSIGNAL_PILOT_IDX(i,srslte_refsignal_cs_nof_symbols(port_id),q->cell)], q->filter_time_ema);
|
|
|
|
|
for (l=1;l<srslte_refsignal_cs_nof_symbols(port_id);l++) {
|
|
|
|
|
pilot_avg(i) = SRSLTE_VEC_EMA(pilot_tmp(i), q->pilot_estimates_average[port_id][SRSLTE_REFSIGNAL_PILOT_IDX(i,l-1,q->cell)], q->filter_time_ema);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
} else {
|
|
|
|
|
/* Filter with FIR or don't filter */
|
|
|
|
|
for (l=0;l<srslte_refsignal_cs_nof_symbols(port_id);l++) {
|
|
|
|
|
/* Filter in time domain. */
|
|
|
|
|
if (q->filter_time_len > 0) {
|
|
|
|
|
/* Move last symbols */
|
|
|
|
|
for (i=0;i<q->filter_time_len-1;i++) {
|
|
|
|
|
memcpy(q->tmp_timeavg[i], q->tmp_timeavg[i+1], nref*sizeof(cf_t));
|
|
|
|
|
}
|
|
|
|
|
/* Save last symbol to buffer */
|
|
|
|
|
memcpy(q->tmp_timeavg[q->filter_time_len-1], &pilot_tmp(0), nref*sizeof(cf_t));
|
|
|
|
|
|
|
|
|
|
/* Multiply all symbols by filter and add them */
|
|
|
|
|
if (l > 0) {
|
|
|
|
|
bzero(&pilot_avg(0), nref * sizeof(cf_t));
|
|
|
|
|
for (i=0;i<q->filter_time_len;i++) {
|
|
|
|
|
srslte_vec_sc_prod_cfc(q->tmp_timeavg[i], q->filter_time[i], q->tmp_timeavg_mult, nref);
|
|
|
|
|
srslte_vec_sum_ccc(q->tmp_timeavg_mult, &pilot_avg(0), &pilot_avg(0), nref);
|
|
|
|
|
}
|
|
|
|
|
/* Filter with FIR or don't filter */
|
|
|
|
|
for (l=0;l<SRSLTE_CP_NSYMB(q->cell.cp);l++) {
|
|
|
|
|
/* Filter in time domain. */
|
|
|
|
|
if (q->filter_time_len > 0) {
|
|
|
|
|
/* Multiply symbols by filter and add them */
|
|
|
|
|
bzero(&ce[l*12*q->cell.nof_prb], nref * sizeof(cf_t));
|
|
|
|
|
for (i=0;i<q->filter_time_len;i++) {
|
|
|
|
|
if (l+i-q->filter_time_len/2 < SRSLTE_CP_NSYMB(q->cell.cp) && l+i-q->filter_time_len/2 > 0) {
|
|
|
|
|
srslte_vec_sc_prod_cfc(&q->tmp_freqavg[(l+i-q->filter_time_len/2)*12*q->cell.nof_prb], q->filter_time[i], q->tmp_timeavg_mult, nref);
|
|
|
|
|
srslte_vec_sum_ccc(q->tmp_timeavg_mult, &ce[l*12*q->cell.nof_prb], &ce[l*12*q->cell.nof_prb], nref);
|
|
|
|
|
} else {
|
|
|
|
|
memcpy(&pilot_avg(0), &pilot_tmp(0), nref * sizeof(cf_t));
|
|
|
|
|
srslte_vec_sc_prod_cfc(&q->tmp_freqavg[l*12*q->cell.nof_prb], q->filter_time[i], q->tmp_timeavg_mult, nref);
|
|
|
|
|
srslte_vec_sum_ccc(q->tmp_timeavg_mult, &ce[l*12*q->cell.nof_prb], &ce[l*12*q->cell.nof_prb], nref);
|
|
|
|
|
}
|
|
|
|
|
} else {
|
|
|
|
|
memcpy(&pilot_avg(0), &pilot_tmp(0), nref * sizeof(cf_t));
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
} else {
|
|
|
|
|
memcpy(&ce[l*12*q->cell.nof_prb], &q->tmp_freqavg[l*12*q->cell.nof_prb], nref * sizeof(cf_t));
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
#define cesymb(i) ce[SRSLTE_RE_IDX(q->cell.nof_prb,i,0)]
|
|
|
|
|
|
|
|
|
|
static void interpolate_pilots(srslte_chest_dl_t *q, cf_t *ce, uint32_t port_id)
|
|
|
|
|
static void interpolate_pilots(srslte_chest_dl_t *q, cf_t *pilot_estimates, cf_t *ce, uint32_t port_id)
|
|
|
|
|
{
|
|
|
|
|
/* interpolate the symbols with references in the freq domain */
|
|
|
|
|
uint32_t l;
|
|
|
|
|
@ -335,7 +278,7 @@ static void interpolate_pilots(srslte_chest_dl_t *q, cf_t *ce, uint32_t port_id)
|
|
|
|
|
/* Interpolate in the frequency domain */
|
|
|
|
|
for (l=0;l<nsymbols;l++) {
|
|
|
|
|
uint32_t fidx_offset = srslte_refsignal_cs_fidx(q->cell, l, port_id, 0);
|
|
|
|
|
srslte_interp_linear_offset(&q->srslte_interp_lin, &pilot_avg(0),
|
|
|
|
|
srslte_interp_linear_offset(&q->srslte_interp_lin, &pilot_estimates[2*q->cell.nof_prb*l],
|
|
|
|
|
&ce[srslte_refsignal_cs_nsymbol(l,q->cell.cp, port_id) * q->cell.nof_prb * SRSLTE_NRE],
|
|
|
|
|
fidx_offset, SRSLTE_NRE/2-fidx_offset);
|
|
|
|
|
}
|
|
|
|
|
@ -399,8 +342,13 @@ int srslte_chest_dl_estimate_port(srslte_chest_dl_t *q, cf_t *input, cf_t *ce, u
|
|
|
|
|
srslte_vec_prod_conj_ccc(q->pilot_recv_signal[port_id], q->csr_signal.pilots[port_id/2][sf_idx],
|
|
|
|
|
q->pilot_estimates[port_id], SRSLTE_REFSIGNAL_NUM_SF(q->cell.nof_prb, port_id));
|
|
|
|
|
|
|
|
|
|
/* Average pilot estimates */
|
|
|
|
|
average_pilots(q, port_id);
|
|
|
|
|
if (ce != NULL) {
|
|
|
|
|
/* Interpolate to create channel estimates for all resource grid */
|
|
|
|
|
interpolate_pilots(q, q->pilot_estimates[port_id], ce, port_id);
|
|
|
|
|
|
|
|
|
|
/* Average channel estimates */
|
|
|
|
|
average_estimates(q, ce, port_id);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
#if NOISE_POWER_METHOD==1
|
|
|
|
|
q->noise_estimate[port_id] = estimate_noise_port(q, input);
|
|
|
|
|
@ -413,11 +361,6 @@ int srslte_chest_dl_estimate_port(srslte_chest_dl_t *q, cf_t *input, cf_t *ce, u
|
|
|
|
|
q->rssi[port_id] = srslte_chest_dl_rssi(q, input, port_id);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Interpolate to create channel estimates for all resource grid */
|
|
|
|
|
if (ce != NULL) {
|
|
|
|
|
interpolate_pilots(q, ce, port_id);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
ismagom
10 years ago