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srsLTE
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Estimate CFO for NR PUCCH formats 0 and 1

This commit is contained in:
Xavier Arteaga 2021-10-13 17:04:46 +02:00
parent 51ff429bc7
commit e6bd6462b1
1 changed files with 47 additions and 11 deletions
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58
lib/src/phy/ch_estimation/dmrs_pucch.c
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@ -14,6 +14,7 @@
#include "srsran/phy/common/sequence.h"
#include "srsran/phy/utils/debug.h"
#include "srsran/phy/utils/vector.h"
#include <complex.h>
// Implements TS 38.211 table 6.4.1.3.1.1-1: Number of DM-RS symbols and the corresponding N_PUCCH...
static uint32_t dmrs_pucch_format1_n_pucch(const srsran_pucch_nr_resource_t* resource, uint32_t m_prime)
@ -217,12 +218,13 @@ int srsran_dmrs_pucch_format1_estimate(const srsran_pucch_nr_t* q,
}
// Perform measurements
float rsrp = 0.0f;
float epre = 0.0f;
float ta_err = 0.0f;
float rsrp = 0.0f;
float epre = 0.0f;
float ta_err = 0.0f;
cf_t corr[SRSRAN_PUCCH_NR_FORMAT1_N_MAX] = {};
for (uint32_t m = 0; m < n_pucch; m++) {
cf_t corr = srsran_vec_acc_cc(ce[m], SRSRAN_NRE) / SRSRAN_NRE;
rsrp += __real__ corr * __real__ corr + __imag__ corr * __imag__ corr;
corr[m] = srsran_vec_acc_cc(ce[m], SRSRAN_NRE) / SRSRAN_NRE;
rsrp += SRSRAN_CSQABS(corr[m]);
epre += srsran_vec_avg_power_cf(ce[m], SRSRAN_NRE);
ta_err += srsran_vec_estimate_frequency(ce[m], SRSRAN_NRE);
}
@ -254,7 +256,22 @@ int srsran_dmrs_pucch_format1_estimate(const srsran_pucch_nr_t* q,
}
// Measure CFO
res->cfo_hz = NAN; // Not implemented
if (n_pucch > 1) {
float cfo_avg_hz = 0.0f;
for (uint32_t m = 0; m < n_pucch - 1; m++) {
uint32_t l0 = resource->start_symbol_idx + m * 2;
uint32_t l1 = resource->start_symbol_idx + (m + 1) * 2;
float time_diff = srsran_symbol_distance_s(l0, l1, q->carrier.scs);
float phase_diff = cargf(corr[m + 1] * conjf(corr[m]));
if (isnormal(time_diff)) {
cfo_avg_hz += phase_diff / (2.0f * M_PI * time_diff * (n_pucch - 1));
}
}
res->cfo_hz = cfo_avg_hz;
} else {
res->cfo_hz = NAN; // Not implemented
}
// Do averaging here
// ... Not implemented
@ -379,12 +396,13 @@ int srsran_dmrs_pucch_format2_estimate(const srsran_pucch_nr_t* q,
}
// Perform measurements
float epre = 0.0f;
float rsrp = 0.0f;
float ta_err = 0.0f;
float epre = 0.0f;
float rsrp = 0.0f;
float ta_err = 0.0f;
cf_t corr[SRSRAN_PUCCH_NR_FORMAT2_MAX_NSYMB] = {};
for (uint32_t i = 0; i < resource->nof_symbols; i++) {
cf_t corr = srsran_vec_acc_cc(ce[i], nof_ref) / nof_ref;
rsrp += __real__ corr * __real__ corr + __imag__ corr * __imag__ corr;
corr[i] = srsran_vec_acc_cc(ce[i], nof_ref) / nof_ref;
rsrp += SRSRAN_CSQABS(corr[i]);
epre += srsran_vec_avg_power_cf(ce[i], nof_ref);
ta_err += srsran_vec_estimate_frequency(ce[i], nof_ref);
}
@ -413,6 +431,24 @@ int srsran_dmrs_pucch_format2_estimate(const srsran_pucch_nr_t* q,
res->ta_us = 0.0f;
}
// Measure CFO
if (resource->nof_symbols > 1) {
float cfo_avg_hz = 0.0f;
for (uint32_t l = 0; l < resource->nof_symbols - 1; l++) {
uint32_t l0 = resource->start_symbol_idx + l;
uint32_t l1 = resource->start_symbol_idx + l + 1;
float time_diff = srsran_symbol_distance_s(l0, l1, q->carrier.scs);
float phase_diff = cargf(corr[l + 1] * conjf(corr[l]));
if (isnormal(time_diff)) {
cfo_avg_hz += phase_diff / (2.0f * M_PI * time_diff * (resource->nof_symbols - 1));
}
}
res->cfo_hz = cfo_avg_hz;
} else {
res->cfo_hz = NAN; // Not implemented
}
// Perform averaging
// ...