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srsLTE
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Fixes in LTE CRS measurements

This commit is contained in:
Xavier Arteaga 2021-05-17 14:39:04 +02:00 committed by Xavier Arteaga
parent 170fbefbf5
commit 7b159563ab
1 changed files with 29 additions and 17 deletions
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46
lib/src/phy/sync/refsignal_dl_sync.c
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@ -68,8 +68,14 @@ static inline void refsignal_sf_prepare_correlation(srsran_refsignal_dl_sync_t*
{
uint32_t sf_len = q->ifft.sf_sz;
cf_t* ptr_filt = q->conv_fft_cc.filter_fft;
memcpy(ptr_filt, q->sequences[0], sizeof(cf_t) * sf_len);
srsran_vec_cf_zero(&ptr_filt[sf_len], sf_len);
// Put first subframe in buffer
srsran_vec_cf_copy(ptr_filt, q->sequences[0], sf_len);
// Zero the rest of the buffer
srsran_vec_cf_zero(&ptr_filt[sf_len], q->conv_fft_cc.output_len - sf_len);
// Make correlation sequence in frequency domain
srsran_dft_run_c(&q->conv_fft_cc.filter_plan, ptr_filt, ptr_filt);
}
@ -249,7 +255,12 @@ int srsran_refsignal_dl_sync_set_cell(srsran_refsignal_dl_sync_t* q, srsran_cell
srsran_ofdm_tx_sf(&q->ifft);
// Undo scaling and normalize overall power to 1
float scale = 1.0f / nof_re;
float scale = 1.0f;
// Avoid zero division
if (nof_re != 0) {
scale /= (float)nof_re;
}
// Copy time domain signal, normalized by number of RE
srsran_vec_sc_prod_cfc(q->ifft_buffer_out, scale, q->sequences[i], q->ifft.sf_sz);
@ -289,22 +300,23 @@ void srsran_refsignal_dl_sync_free(srsran_refsignal_dl_sync_t* q)
}
}
int srsran_refsignal_dl_sync_find_peak(srsran_refsignal_dl_sync_t* q, cf_t* buffer, uint32_t nsamples)
int refsignal_dl_sync_find_peak(srsran_refsignal_dl_sync_t* q, cf_t* buffer, uint32_t nsamples)
{
int ret = SRSRAN_ERROR;
float peak_value = 0.0f;
int peak_idx = 0;
float rms_avg = 0;
uint32_t sf_len = q->ifft.sf_sz;
int ret = SRSRAN_ERROR;
float peak_value = 0.0f;
int peak_idx = 0;
float rms_avg = 0;
uint32_t sf_len = q->ifft.sf_sz;
if (sf_len == 0) {
return SRSRAN_ERROR;
}
// Load correlation sequence and convert to frequency domain
refsignal_sf_prepare_correlation(q);
// Limit correlate for a frame or less
nsamples = SRSRAN_MIN(nsamples - sf_len, SRSRAN_NOF_SF_X_FRAME * sf_len);
// Correlation
for (int n = 0; n < nsamples; n += sf_len) {
for (uint32_t n = 0; n + q->conv_fft_cc.filter_len < nsamples; n += q->conv_fft_cc.input_len) {
// Correlate, find maximum, calculate RMS and peak
uint32_t imax = 0;
float peak = 0.0f;
@ -327,7 +339,7 @@ int srsran_refsignal_dl_sync_find_peak(srsran_refsignal_dl_sync_t* q, cf_t* buff
}
// Double check sub-frame selection failure due to high PSS
if (ret > 0) {
if (ret >= 0) {
float sss_strength = 0.0f;
float sss_strength_false = 0.0f;
refsignal_dl_pss_sss_strength(q, &buffer[peak_idx], 0, NULL, &sss_strength, &sss_strength_false);
@ -373,15 +385,15 @@ void srsran_refsignal_dl_sync_run(srsran_refsignal_dl_sync_t* q, cf_t* buffer, u
bool false_alarm = false;
// Stage 1: find peak
int peak_idx = srsran_refsignal_dl_sync_find_peak(q, buffer, nsamples);
int peak_idx = refsignal_dl_sync_find_peak(q, buffer, nsamples);
// Stage 2: Proccess subframes
if (peak_idx >= 0) {
// Calculate initial subframe index and sample
uint32_t sf_idx_init = (2 * SRSRAN_NOF_SF_X_FRAME - peak_idx / sf_len) % SRSRAN_NOF_SF_X_FRAME;
uint32_t sf_idx_init = SRSRAN_NOF_SF_X_FRAME - (peak_idx / sf_len) % SRSRAN_NOF_SF_X_FRAME;
uint32_t n_init = peak_idx % sf_len;
for (int sf_idx = sf_idx_init, n = n_init; n < (nsamples - sf_len + 1);
for (uint32_t sf_idx = sf_idx_init, n = n_init; n < (nsamples - sf_len + 1);
sf_idx = (sf_idx + 1) % SRSRAN_NOF_SF_X_FRAME, n += sf_len) {
cf_t* buf = &buffer[n];