mirror of https://github.com/PentHertz/srsLTE.git
chest_dl: subframe averaging with previous
This commit is contained in:
Ismael Gomez
parent
58d955ea10
commit
82cfa01468
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@ -63,6 +63,7 @@ typedef struct {
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srslte_refsignal_cs_t csr_signal;
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cf_t *pilot_estimates;
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cf_t *pilot_estimates_average;
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cf_t *pilot_average_last;
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cf_t *pilot_recv_signal;
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cf_t *tmp_noise;
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@ -73,6 +74,9 @@ typedef struct {
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uint32_t smooth_filter_len;
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float smooth_filter[SRSLTE_CHEST_MAX_SMOOTH_FIL_LEN];
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float time_ema_coeff;
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bool average_subframe;
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srslte_interp_linsrslte_vec_t srslte_interp_linvec;
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srslte_interp_lin_t srslte_interp_lin;
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@ -102,6 +106,12 @@ SRSLTE_API void srslte_chest_dl_set_smooth_filter(srslte_chest_dl_t *q,
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SRSLTE_API void srslte_chest_dl_set_smooth_filter3_coeff(srslte_chest_dl_t* q,
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float w);
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SRSLTE_API void srslte_chest_dl_set_time_ema_coeff(srslte_chest_dl_t *q,
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float t);
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SRSLTE_API void srslte_chest_dl_set_average_subframe(srslte_chest_dl_t *q,
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bool enable);
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SRSLTE_API void srslte_chest_dl_set_noise_alg(srslte_chest_dl_t *q,
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srslte_chest_dl_noise_alg_t noise_estimation_alg);
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@ -39,32 +39,8 @@
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#include "srslte/utils/vector.h"
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#include "srslte/utils/convolution.h"
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#define AVERAGE_SUBFRAME
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//#define DEFAULT_FILTER_LEN 3
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#ifdef DEFAULT_FILTER_LEN
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static void set_default_filter(srslte_chest_dl_t *q, int filter_len) {
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float fil[SRSLTE_CHEST_DL_MAX_SMOOTH_FIL_LEN];
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for (int i=0;i<filter_len/2;i++) {
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fil[i] = i+1;
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fil[i+filter_len/2+1]=filter_len/2-i;
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}
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fil[filter_len/2]=filter_len/2+1;
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float s=0;
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for (int i=0;i<filter_len;i++) {
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s+=fil[i];
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}
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for (int i=0;i<filter_len;i++) {
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fil[i]/=s;
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}
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srslte_chest_dl_set_smooth_filter(q, fil, filter_len);
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}
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#endif
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#define DEFAULT_FILTER_LEN 3
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#define DEFAULT_TIME_EMA_COEFF 0.9
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/** 3GPP LTE Downlink channel estimator and equalizer.
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* Estimates the channel in the resource elements transmitting references and interpolates for the rest
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@ -104,6 +80,11 @@ int srslte_chest_dl_init(srslte_chest_dl_t *q, srslte_cell_t cell)
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perror("malloc");
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goto clean_exit;
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}
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q->pilot_average_last = srslte_vec_malloc(sizeof(cf_t) * 2 * cell.nof_prb);
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if (!q->pilot_average_last) {
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perror("malloc");
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goto clean_exit;
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}
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q->pilot_recv_signal = srslte_vec_malloc(sizeof(cf_t) * SRSLTE_REFSIGNAL_MAX_NUM_SF(cell.nof_prb));
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if (!q->pilot_recv_signal) {
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perror("malloc");
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@ -127,7 +108,14 @@ int srslte_chest_dl_init(srslte_chest_dl_t *q, srslte_cell_t cell)
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q->noise_alg = SRSLTE_NOISE_ALG_REFS;
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q->smooth_filter_len = 3;
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q->time_ema_coeff = 1.0;
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#ifdef DEFAULT_TIME_EMA_COEFF
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q->time_ema_coeff = DEFAULT_TIME_EMA_COEFF;
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#endif
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q->average_subframe = true;
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q->smooth_filter_len = DEFAULT_FILTER_LEN;
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srslte_chest_dl_set_smooth_filter3_coeff(q, 0.1);
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q->cell = cell;
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@ -158,6 +146,9 @@ void srslte_chest_dl_free(srslte_chest_dl_t *q)
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if (q->pilot_estimates_average) {
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free(q->pilot_estimates_average);
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}
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if (q->pilot_average_last) {
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free(q->pilot_average_last);
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}
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if (q->pilot_recv_signal) {
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free(q->pilot_recv_signal);
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}
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@ -233,52 +224,52 @@ static float estimate_noise_empty_sc(srslte_chest_dl_t *q, cf_t *input) {
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static void interpolate_pilots(srslte_chest_dl_t *q, cf_t *pilot_estimates, cf_t *ce, uint32_t port_id)
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{
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#ifdef AVERAGE_SUBFRAME
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// Interpolate symbol 0 in the frequency domain
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uint32_t fidx_offset = srslte_refsignal_cs_fidx(q->cell, 0, port_id, 0);
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srslte_interp_linear_offset(&q->srslte_interp_lin, pilot_estimates,
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&ce[srslte_refsignal_cs_nsymbol(0,q->cell.cp, port_id) * q->cell.nof_prb * SRSLTE_NRE],
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fidx_offset, SRSLTE_NRE/2-fidx_offset);
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// All channel estimates in the subframe are the same
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for (int l=1;l<2*SRSLTE_CP_NSYMB(q->cell.cp);l++) {
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memcpy(&ce[l*q->cell.nof_prb*SRSLTE_NRE], ce, q->cell.nof_prb*SRSLTE_NRE*sizeof(cf_t));
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}
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#else
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uint32_t l=0;
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uint32_t nsymbols = srslte_refsignal_cs_nof_symbols(port_id);
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// Interpolate in the frequency domain
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for (l=0;l<nsymbols;l++) {
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uint32_t fidx_offset = srslte_refsignal_cs_fidx(q->cell, l, port_id, 0);
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srslte_interp_linear_offset(&q->srslte_interp_lin, &pilot_estimates[2*q->cell.nof_prb*l],
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&ce[srslte_refsignal_cs_nsymbol(l,q->cell.cp, port_id) * q->cell.nof_prb * SRSLTE_NRE],
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fidx_offset, SRSLTE_NRE/2-fidx_offset);
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}
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// Interpolate in the time domain between symbols
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if (SRSLTE_CP_ISNORM(q->cell.cp)) {
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if (nsymbols == 4) {
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(0), &cesymb(4), &cesymb(1), 4, 3);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(4), &cesymb(7), &cesymb(5), 3, 2);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(7), &cesymb(11), &cesymb(8), 4, 3);
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srslte_interp_linear_vector2(&q->srslte_interp_linvec, &cesymb(7), &cesymb(11), &cesymb(11), &cesymb(12), 4, 2);
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} else {
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srslte_interp_linear_vector2(&q->srslte_interp_linvec, &cesymb(8), &cesymb(1), &cesymb(1), &cesymb(0), 7, 1);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(1), &cesymb(8), &cesymb(2), 7, 6);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(1), &cesymb(8), &cesymb(9), 7, 5);
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}
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if (q->average_subframe) {
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// Interpolate symbol 0 in the frequency domain
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uint32_t fidx_offset = srslte_refsignal_cs_fidx(q->cell, 0, port_id, 0);
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srslte_interp_linear_offset(&q->srslte_interp_lin, pilot_estimates,
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&ce[srslte_refsignal_cs_nsymbol(0,q->cell.cp, port_id) * q->cell.nof_prb * SRSLTE_NRE],
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fidx_offset, SRSLTE_NRE/2-fidx_offset);
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// All channel estimates in the subframe are the same
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for (int l=1;l<2*SRSLTE_CP_NSYMB(q->cell.cp);l++) {
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memcpy(&ce[l*q->cell.nof_prb*SRSLTE_NRE], ce, q->cell.nof_prb*SRSLTE_NRE*sizeof(cf_t));
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}
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} else {
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if (nsymbols == 4) {
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(0), &cesymb(3), &cesymb(1), 3, 2);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(3), &cesymb(6), &cesymb(4), 3, 2);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(6), &cesymb(9), &cesymb(7), 3, 2);
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srslte_interp_linear_vector2(&q->srslte_interp_linvec, &cesymb(6), &cesymb(9), &cesymb(9), &cesymb(10), 3, 2);
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uint32_t l=0;
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uint32_t nsymbols = srslte_refsignal_cs_nof_symbols(port_id);
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// Interpolate in the frequency domain
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for (l=0;l<nsymbols;l++) {
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uint32_t fidx_offset = srslte_refsignal_cs_fidx(q->cell, l, port_id, 0);
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srslte_interp_linear_offset(&q->srslte_interp_lin, &pilot_estimates[2*q->cell.nof_prb*l],
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&ce[srslte_refsignal_cs_nsymbol(l,q->cell.cp, port_id) * q->cell.nof_prb * SRSLTE_NRE],
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fidx_offset, SRSLTE_NRE/2-fidx_offset);
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}
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// Interpolate in the time domain between symbols
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if (SRSLTE_CP_ISNORM(q->cell.cp)) {
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if (nsymbols == 4) {
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(0), &cesymb(4), &cesymb(1), 4, 3);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(4), &cesymb(7), &cesymb(5), 3, 2);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(7), &cesymb(11), &cesymb(8), 4, 3);
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srslte_interp_linear_vector2(&q->srslte_interp_linvec, &cesymb(7), &cesymb(11), &cesymb(11), &cesymb(12), 4, 2);
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} else {
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srslte_interp_linear_vector2(&q->srslte_interp_linvec, &cesymb(8), &cesymb(1), &cesymb(1), &cesymb(0), 7, 1);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(1), &cesymb(8), &cesymb(2), 7, 6);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(1), &cesymb(8), &cesymb(9), 7, 5);
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}
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} else {
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srslte_interp_linear_vector2(&q->srslte_interp_linvec, &cesymb(7), &cesymb(1), &cesymb(1), &cesymb(0), 6, 1);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(1), &cesymb(7), &cesymb(2), 6, 5);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(1), &cesymb(7), &cesymb(8), 6, 4);
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}
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if (nsymbols == 4) {
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(0), &cesymb(3), &cesymb(1), 3, 2);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(3), &cesymb(6), &cesymb(4), 3, 2);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(6), &cesymb(9), &cesymb(7), 3, 2);
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srslte_interp_linear_vector2(&q->srslte_interp_linvec, &cesymb(6), &cesymb(9), &cesymb(9), &cesymb(10), 3, 2);
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} else {
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srslte_interp_linear_vector2(&q->srslte_interp_linvec, &cesymb(7), &cesymb(1), &cesymb(1), &cesymb(0), 6, 1);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(1), &cesymb(7), &cesymb(2), 6, 5);
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srslte_interp_linear_vector(&q->srslte_interp_linvec, &cesymb(1), &cesymb(7), &cesymb(8), 6, 4);
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}
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}
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}
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#endif
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}
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void srslte_chest_dl_set_smooth_filter(srslte_chest_dl_t *q, float *filter, uint32_t filter_len) {
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@ -307,21 +298,36 @@ void srslte_chest_dl_set_smooth_filter3_coeff(srslte_chest_dl_t* q, float w)
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q->smooth_filter[1] = 1-2*w;
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}
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void srslte_chest_dl_set_time_ema_coeff(srslte_chest_dl_t *q, float t) {
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if (t > 0.0 && t <= 1.0) {
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q->time_ema_coeff = t;
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}
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}
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void srslte_chest_dl_set_average_subframe(srslte_chest_dl_t *q, bool enable) {
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q->average_subframe = enable;
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}
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static void average_pilots(srslte_chest_dl_t *q, cf_t *input, cf_t *output, uint32_t port_id) {
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uint32_t nsymbols = srslte_refsignal_cs_nof_symbols(port_id);
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uint32_t nref = 2*q->cell.nof_prb;
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memcpy(output, input, nref*sizeof(cf_t));
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for (int l=1;l<nsymbols;l++) {
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#ifdef AVERAGE_SUBFRAME
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srslte_vec_sum_ccc(output, &input[l*nref], output, nref);
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#else
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srslte_conv_same_cf(&input[l*nref], q->smooth_filter, &output[l*nref], nref, q->smooth_filter_len);
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#endif
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if (q->average_subframe) {
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srslte_vec_sum_ccc(output, &input[l*nref], output, nref);
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} else {
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srslte_conv_same_cf(&input[l*nref], q->smooth_filter, &output[l*nref], nref, q->smooth_filter_len);
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}
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}
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if (q->average_subframe) {
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srslte_vec_sc_prod_cfc(output, (float) q->time_ema_coeff/nsymbols, output, nref);
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if (q->time_ema_coeff < 1.0) {
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srslte_vec_sc_prod_cfc(q->pilot_average_last, 1-q->time_ema_coeff, q->pilot_average_last, nref);
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srslte_vec_sum_ccc(q->pilot_average_last, output, output, nref);
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memcpy(q->pilot_average_last, output, nref*sizeof(cf_t));
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}
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}
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#ifdef AVERAGE_SUBFRAME
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srslte_vec_sc_prod_cfc(output, (float) 1.0/nsymbols, output, nref);
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#endif
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}
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float srslte_chest_dl_rssi(srslte_chest_dl_t *q, cf_t *input, uint32_t port_id) {
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