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Improve PDCCH NR detection

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master
Xavier Arteaga 4 years ago committed by Andre Puschmann
parent 1a6e5cdee5
commit 42dcff45b2
2 changed files with 58 additions and 22 deletions
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67
lib/src/phy/ch_estimation/dmrs_pdcch.c
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@ -23,12 +23,26 @@
/// per frequency resource.
#define NOF_PILOTS_X_FREQ_RES 18
///@brief Maximum number of pilots in a PDCCH candidate location
#define DMRS_PDCCH_MAX_NOF_PILOTS_CANDIDATE \
((SRSRAN_NRE / 3) * (1U << (SRSRAN_SEARCH_SPACE_NOF_AGGREGATION_LEVELS_NR - 1U)) * 6U)
#define DMRS_PDCCH_INFO_TX(...) INFO("PDCCH DMRS Tx: " __VA_ARGS__)
#define DMRS_PDCCH_INFO_RX(...) INFO("PDCCH DMRS Rx: " __VA_ARGS__)
#define DMRS_PDCCH_DEBUG_RX(...) DEBUG("PDCCH DMRS Rx: " __VA_ARGS__)
/// @brief Enables interpolation at CCE frequency bandwidth to avoid interference with adjacent PDCCH DMRS
#define DMRS_PDCCH_INTERPOLATE_GROUP 1
///@brief Enables synchronization error pre-compensation before group interpolator. It should decrease EVM in expense of
/// computing complexity.
#define DMRS_PDCCH_SYNC_PRECOMPENSATE_INTERP 0
///@brief Enables synchronization error pre-compensation before candidate measurement. It improves detection probability
/// in expense of computing complexity.
#define DMRS_PDCCH_SYNC_PRECOMPENSATE_MEAS 1
///@brief Enables/Disables smoothing filter
#define DMRS_PDCCH_SMOOTH_FILTER 0
static uint32_t dmrs_pdcch_get_cinit(uint32_t slot_idx, uint32_t symbol_idx, uint32_t n_id)
@ -362,21 +376,32 @@ int srsran_dmrs_pdcch_estimate(srsran_dmrs_pdcch_estimator_t* q,
uint32_t group_size = NOF_PILOTS_X_FREQ_RES / q->coreset.duration;
for (uint32_t l = 0; l < q->coreset.duration; l++) {
for (uint32_t j = 0; j < group_count; j++) {
#if DMRS_PDCCH_SMOOTH_FILTER
cf_t tmp[NOF_PILOTS_X_FREQ_RES];
// Copy group into temporal vector
srsran_vec_cf_copy(tmp, &q->lse[l][j * group_size], group_size);
#if DMRS_PDCCH_SYNC_PRECOMPENSATE_INTERP
float sync_err = srsran_vec_estimate_frequency(tmp, group_size);
if (isnormal(sync_err)) {
srsran_vec_apply_cfo(tmp, sync_err, tmp, group_size);
}
#endif // DMRS_PDCCH_SYNC_PRECOMPENSATION
#if DMRS_PDCCH_SMOOTH_FILTER
// Smoothing filter group
srsran_conv_same_cf(&q->lse[l][j * group_size], q->filter, tmp, group_size, q->filter_len);
srsran_interp_linear_offset(
&q->interpolator, tmp, &q->ce[SRSRAN_NRE * q->coreset_bw * l + j * group_size * 4], 1, 3);
#else // DMRS_PDCCH_SMOOTH_FILTER
srsran_interp_linear_offset(&q->interpolator,
&q->lse[l][j * group_size],
&q->ce[SRSRAN_NRE * q->coreset_bw * l + j * group_size * 4],
1,
3);
srsran_conv_same_cf(tmp, q->filter, tmp, group_size, q->filter_len);
#endif // DMRS_PDCCH_SMOOTH_FILTER
// Interpolate group
cf_t* dst = &q->ce[SRSRAN_NRE * q->coreset_bw * l + j * group_size * 4];
srsran_interp_linear_offset(&q->interpolator, tmp, dst, 1, 3);
#if DMRS_PDCCH_SYNC_PRECOMPENSATE_INTERP
if (isnormal(sync_err)) {
srsran_vec_apply_cfo(dst, -sync_err / 4, dst, group_size * 4);
}
#endif // DMRS_PDCCH_SYNC_PRECOMPENSATION
}
}
#else // DMRS_PDCCH_INTERPOLATE_GROUP
@ -423,22 +448,32 @@ int srsran_dmrs_pdcch_get_measure(const srsran_dmrs_pdcch_estimator_t* q,
srsran_vec_fprint_c(stdout, &q->lse[l][pilot_idx], nof_pilots);
}
// Measure synchronization error
float tmp_sync_err = srsran_vec_estimate_frequency(&q->lse[l][pilot_idx], nof_pilots);
sync_err += tmp_sync_err;
#if DMRS_PDCCH_SYNC_PRECOMPENSATE_MEAS
cf_t tmp[DMRS_PDCCH_MAX_NOF_PILOTS_CANDIDATE];
// Pre-compensate synchronization error
srsran_vec_apply_cfo(&q->lse[l][pilot_idx], tmp_sync_err, tmp, nof_pilots);
#else // DMRS_PDCCH_SYNC_PRECOMPENSATE_MEAS
const cf_t* tmp = &q->lse[l][pilot_idx];
#endif // DMRS_PDCCH_SYNC_PRECOMPENSATE_MEAS
// Correlate DMRS
corr[l] = srsran_vec_acc_cc(&q->lse[l][pilot_idx], nof_pilots) / (float)nof_pilots;
corr[l] = srsran_vec_acc_cc(tmp, nof_pilots) / (float)nof_pilots;
// Measure symbol RSRP
rsrp += __real__ corr[l] * __real__ corr[l] + __imag__ corr[l] * __imag__ corr[l];
// Measure symbol EPRE
epre += srsran_vec_avg_power_cf(&q->lse[l][pilot_idx], nof_pilots);
epre += srsran_vec_avg_power_cf(tmp, nof_pilots);
// Measure CFO only from the second and third symbols
if (l != 0) {
cfo += cargf(corr[l] * conjf(corr[l - 1]));
}
// Measure synchronization error
sync_err += srsran_vec_estimate_frequency(&q->lse[l][pilot_idx], nof_pilots);
}
if (q->coreset.duration > 1) {

13
lib/src/phy/phch/pdcch_nr.c
Unescape Escape View File

@ -24,6 +24,7 @@
#define PDCCH_INFO_TX(...) INFO("PDCCH Tx: " __VA_ARGS__)
#define PDCCH_INFO_RX(...) INFO("PDCCH Rx: " __VA_ARGS__)
#define PDCCH_DEBUG_RX(...) DEBUG("PDCCH Rx: " __VA_ARGS__)
/**
* @brief Recursive Y_p_n function
@ -473,8 +474,8 @@ int srsran_pdcch_nr_decode(srsran_pdcch_nr_t* q,
}
// Print channel estimates if enabled
if (SRSRAN_DEBUG_ENABLED && srsran_verbose >= SRSRAN_VERBOSE_INFO && !handler_registered) {
PDCCH_INFO_RX("ce=");
if (SRSRAN_DEBUG_ENABLED && srsran_verbose >= SRSRAN_VERBOSE_DEBUG && !handler_registered) {
PDCCH_DEBUG_RX("ce=");
srsran_vec_fprint_c(stdout, ce->ce, q->M);
}
@ -482,8 +483,8 @@ int srsran_pdcch_nr_decode(srsran_pdcch_nr_t* q,
srsran_predecoding_single(q->symbols, ce->ce, q->symbols, NULL, q->M, 1.0f, ce->noise_var);
// Print symbols if enabled
if (SRSRAN_DEBUG_ENABLED && srsran_verbose >= SRSRAN_VERBOSE_INFO && !handler_registered) {
PDCCH_INFO_RX("symbols=");
if (SRSRAN_DEBUG_ENABLED && srsran_verbose >= SRSRAN_VERBOSE_DEBUG && !handler_registered) {
PDCCH_DEBUG_RX("symbols=");
srsran_vec_fprint_c(stdout, q->symbols, q->M);
}
@ -513,8 +514,8 @@ int srsran_pdcch_nr_decode(srsran_pdcch_nr_t* q,
}
// Print d
if (SRSRAN_DEBUG_ENABLED && srsran_verbose >= SRSRAN_VERBOSE_INFO && !handler_registered) {
PDCCH_INFO_RX("d=");
if (SRSRAN_DEBUG_ENABLED && srsran_verbose >= SRSRAN_VERBOSE_DEBUG && !handler_registered) {
PDCCH_DEBUG_RX("d=");
srsran_vec_fprint_bs(stdout, d, q->K);
}

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