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srsLTE
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Changed sync() to return always 1 if the peak is found

This commit is contained in:
ismagom 2014-11-24 18:50:38 +00:00
parent 21636025af
commit cbe159a77b
2 changed files with 43 additions and 30 deletions
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65
lte/phy/lib/sync/src/sync.c
View File

@ -186,6 +186,9 @@ static lte_cp_t detect_cp(sync_t *q, cf_t *input, uint32_t peak_pos)
}
}
/* Returns 1 if the SSS is found, 0 if not and -1 if there is not enough space
* to correlate
*/
int sync_sss(sync_t *q, cf_t *input, uint32_t peak_pos) {
int sss_idx, ret;
@ -199,7 +202,7 @@ int sync_sss(sync_t *q, cf_t *input, uint32_t peak_pos) {
sss_idx = (int) peak_pos - 2*(q->fft_size + CP(q->fft_size, q->cp));
if (sss_idx < 0) {
INFO("Not enough room to decode CP SSS (sss_idx=%d, peak_pos=%d)\n", sss_idx, peak_pos);
return LIBLTE_SUCCESS;
return LIBLTE_ERROR;
}
sss_synch_m0m1(&q->sss, &input[sss_idx], &q->m0, &q->m0_value, &q->m1, &q->m1_value);
@ -208,16 +211,23 @@ int sync_sss(sync_t *q, cf_t *input, uint32_t peak_pos) {
ret = sss_synch_N_id_1(&q->sss, q->m0, q->m1);
if (ret >= 0) {
q->N_id_1 = (uint32_t) ret;
DEBUG("SSS detected N_id_1=%d, sf_idx=%d, %s CP\n",
q->N_id_1, q->sf_idx, CP_ISNORM(q->cp)?"Normal":"Extended");
return 1;
} else {
q->N_id_1 = 1000;
return LIBLTE_SUCCESS;
}
DEBUG("SSS detected N_id_1=%d, sf_idx=%d, %s CP\n",
q->N_id_1, q->sf_idx, CP_ISNORM(q->cp)?"Normal":"Extended");
return 1;
}
/** Finds the PSS sequence previously defined by a call to sync_set_N_id_2()
* around the position find_offset in the buffer input.
* Returns 1 if the correlation peak exceeds the threshold set by sync_set_threshold()
* or 0 otherwise. Returns a negative number on error (if N_id_2 has not been set)
*
* The maximum of the correlation peak is always stored in *peak_position
*/
int sync_find(sync_t *q, cf_t *input, uint32_t find_offset, uint32_t *peak_position)
{
@ -249,8 +259,7 @@ int sync_find(sync_t *q, cf_t *input, uint32_t find_offset, uint32_t *peak_posit
peak_pos + find_offset >= q->fft_size)
{
/* Compute the energy of the received PSS sequence to normalize */
cf_t *pss_ptr = &input[find_offset+peak_pos-q->fft_size];
energy = sqrtf(crealf(vec_dot_prod_conj_ccc(pss_ptr, pss_ptr, q->fft_size)) / (q->fft_size));
energy = sqrtf(vec_avg_power_cf(&input[find_offset+peak_pos-q->fft_size], q->fft_size));
q->mean_energy = VEC_CMA(energy, q->mean_energy, q->frame_cnt);
} else {
if (q->mean_energy == 0.0) {
@ -263,28 +272,34 @@ int sync_find(sync_t *q, cf_t *input, uint32_t find_offset, uint32_t *peak_posit
q->peak_value = peak_unnormalized/energy;
q->mean_peak_value = VEC_CMA(q->peak_value, q->mean_peak_value, q->frame_cnt);
q->frame_cnt++;
if (peak_position) {
*peak_position = (uint32_t) peak_pos;
}
/* If peak is over threshold, compute CFO and SSS */
if (q->peak_value >= q->threshold) {
if (find_offset + peak_pos >= q->fft_size + CP_EXT(q->fft_size)) {
q->cfo = pss_synch_cfo_compute(&q->pss, &input[find_offset+peak_pos-q->fft_size]);
if (q->sss_en) {
ret = sync_sss(q, input, find_offset + peak_pos);
if (ret < 0) {
fprintf(stderr, "Error synchronizing with SSS\n");
return LIBLTE_ERROR;
}
} else {
ret = 1;
}
} else {
INFO("No space for CFO computation: frame starts at \n",peak_pos);
}
if (peak_position) {
*peak_position = (uint32_t) peak_pos;
// Set an invalid N_id_1 indicating SSS is yet to be detected
q->N_id_1 = 1000;
// Try to detect SSS
if (q->sss_en) {
if (sync_sss(q, input, find_offset + peak_pos) < 0) {
INFO("No space for SSS processing. Frame starts at %d\n", peak_pos);
}
}
}
// Make sure we have enough space to estimate CFO
if (find_offset + peak_pos >= q->fft_size + CP_EXT(q->fft_size)) {
q->cfo = pss_synch_cfo_compute(&q->pss, &input[find_offset+peak_pos-q->fft_size]);
} else {
INFO("No space for CFO computation. Frame starts at \n",peak_pos);
}
// Return 1 (peak detected) even if we couldn't estimate CFO and SSS
ret = 1;
} else {
ret = 0;
}
INFO("SYNC ret=%d N_id_2=%d pos=%d peak=%.2f/%.2f=%.2f threshold=%.2f sf_idx=%d offset=%d\n",
ret, q->N_id_2, peak_pos, peak_unnormalized,energy,q->peak_value, q->threshold, q->sf_idx, find_offset);

8
lte/phy/lib/ue/src/ue_celldetect.c
View File

@ -226,11 +226,6 @@ int ue_celldetect_scan(ue_celldetect_t * q,
return LIBLTE_ERROR;
}
/* If peak position does not allow to read SSS, return error -3 */
if (ret == LIBLTE_SUCCESS && peak_idx != 0) {
return CS_FRAME_UNALIGNED;
}
/* Process the peak result */
if (ret == 1) {
if (sync_sss_detected(&q->sfind)) {
@ -247,6 +242,9 @@ int ue_celldetect_scan(ue_celldetect_t * q,
q->candidates[q->current_nof_detected].peak, q->candidates[q->current_nof_detected].cell_id,
lte_cp_string(q->candidates[q->current_nof_detected].cp));
q->current_nof_detected++;
} else {
/* If peak position does not allow to read SSS, return error -3 */
return CS_FRAME_UNALIGNED;
}
}
q->current_nof_total++;