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@ -39,8 +39,6 @@
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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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@ -167,18 +165,7 @@ void srslte_chest_dl_free(srslte_chest_dl_t *q)
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/* Uses the difference between the averaged and non-averaged pilot estimates */
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static float estimate_noise_pilots(srslte_chest_dl_t *q, uint32_t port_id)
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{
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float norm = sqrt(2);
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#ifdef AVERAGE_SUBFRAME
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int nref=2*q->cell.nof_prb;
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#else
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int nref=SRSLTE_REFSIGNAL_NUM_SF(q->cell.nof_prb, port_id);
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if (q->smooth_filter_len == 3) {
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float a = q->smooth_filter[0];
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float norm3 = 6.143*a*a+0.04859*a-0.002774;
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norm /= norm3;
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}
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#endif
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/* Substract noisy pilot estimates */
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srslte_vec_sub_ccc(q->pilot_estimates_average, q->pilot_estimates, q->tmp_noise, nref);
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@ -192,6 +179,12 @@ static float estimate_noise_pilots(srslte_chest_dl_t *q, uint32_t port_id)
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#endif
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/* Compute average power. Normalized for filter len 3 using matlab */
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float norm = 1;
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if (q->smooth_filter_len == 3) {
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float a = q->smooth_filter[0];
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float norm3 = 6.143*a*a+0.04859*a-0.002774;
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norm /= norm3;
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}
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float power = norm*q->cell.nof_ports*srslte_vec_avg_power_cf(q->tmp_noise, nref);
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return power;
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}
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@ -232,29 +225,19 @@ 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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/* interpolate the symbols with references in the freq domain */
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uint32_t l;
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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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/* 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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/* Now 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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@ -278,7 +261,6 @@ static void interpolate_pilots(srslte_chest_dl_t *q, cf_t *pilot_estimates, cf_t
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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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#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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@ -311,17 +293,9 @@ static void average_pilots(srslte_chest_dl_t *q, cf_t *input, cf_t *output, uint
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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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for (int l=0;l<nsymbols;l++) {
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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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}
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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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