/** * * \section COPYRIGHT * * Copyright 2013-2015 Software Radio Systems Limited * * \section LICENSE * * This file is part of the srsLTE library. * * srsLTE is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as * published by the Free Software Foundation, either version 3 of * the License, or (at your option) any later version. * * srsLTE is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * A copy of the GNU Affero General Public License can be found in * the LICENSE file in the top-level directory of this distribution * and at http://www.gnu.org/licenses/. * */ #include #include #include #include #include #include "srslte/ue/ue_sync.h" #include "srslte/io/filesource.h" #include "srslte/utils/debug.h" #include "srslte/utils/vector.h" #define MAX_TIME_OFFSET 128 #define TRACK_MAX_LOST 4 #define TRACK_FRAME_SIZE 32 #define FIND_NOF_AVG_FRAMES 4 #define DEFAULT_SAMPLE_OFFSET_CORRECT_PERIOD 0 #define DEFAULT_SFO_EMA_COEFF 0.1 cf_t dummy_buffer0[15*2048/2]; cf_t dummy_buffer1[15*2048/2]; // FIXME: this will break for 4 antennas!! cf_t *dummy_offset_buffer[SRSLTE_MAX_PORTS] = {dummy_buffer0, dummy_buffer1}; int srslte_ue_sync_init_file(srslte_ue_sync_t *q, uint32_t nof_prb, char *file_name, int offset_time, float offset_freq) { int ret = SRSLTE_ERROR_INVALID_INPUTS; if (q != NULL && file_name != NULL && srslte_nofprb_isvalid(nof_prb)) { ret = SRSLTE_ERROR; bzero(q, sizeof(srslte_ue_sync_t)); q->file_mode = true; q->sf_len = SRSLTE_SF_LEN(srslte_symbol_sz(nof_prb)); q->file_cfo = -offset_freq; q->correct_cfo = true; q->fft_size = srslte_symbol_sz(nof_prb); if (srslte_cfo_init(&q->file_cfo_correct, 2*q->sf_len)) { fprintf(stderr, "Error initiating CFO\n"); goto clean_exit; } if (srslte_filesource_init(&q->file_source, file_name, SRSLTE_COMPLEX_FLOAT_BIN)) { fprintf(stderr, "Error opening file %s\n", file_name); goto clean_exit; } INFO("Offseting input file by %d samples and %.1f kHz\n", offset_time, offset_freq/1000); srslte_filesource_read(&q->file_source, dummy_offset_buffer, offset_time); srslte_ue_sync_reset(q); ret = SRSLTE_SUCCESS; } clean_exit: if (ret == SRSLTE_ERROR) { srslte_ue_sync_free(q); } return ret; } int srslte_ue_sync_start_agc(srslte_ue_sync_t *q, double (set_gain_callback)(void*, double), float init_gain_value) { uint32_t nframes; if (q->nof_recv_sf == 1) { nframes = 10; } else { nframes = 0; } int n = srslte_agc_init_uhd(&q->agc, SRSLTE_AGC_MODE_PEAK_AMPLITUDE, nframes, set_gain_callback, q->stream); q->do_agc = n==0?true:false; if (q->do_agc) { srslte_agc_set_gain(&q->agc, init_gain_value); } return n; } int recv_callback_multi_to_single(void *h, cf_t *x[SRSLTE_MAX_PORTS], uint32_t nsamples, srslte_timestamp_t*t) { srslte_ue_sync_t *q = (srslte_ue_sync_t*) h; return q->recv_callback_single(q->stream_single, (void*) x[0], nsamples, t); } int srslte_ue_sync_init(srslte_ue_sync_t *q, srslte_cell_t cell, int (recv_callback)(void*, void*, uint32_t,srslte_timestamp_t*), void *stream_handler) { int ret = srslte_ue_sync_init_multi(q, cell, recv_callback_multi_to_single, 1, (void*) q); q->recv_callback_single = recv_callback; q->stream_single = stream_handler; return ret; } int srslte_ue_sync_init_multi(srslte_ue_sync_t *q, srslte_cell_t cell, int (recv_callback)(void*, cf_t*[SRSLTE_MAX_PORTS], uint32_t,srslte_timestamp_t*), uint32_t nof_rx_antennas, void *stream_handler) { return srslte_ue_sync_init_multi_decim(q, cell,recv_callback ,nof_rx_antennas,stream_handler,1); } int srslte_ue_sync_init_multi_decim(srslte_ue_sync_t *q, srslte_cell_t cell, int (recv_callback)(void*, cf_t*[SRSLTE_MAX_PORTS], uint32_t,srslte_timestamp_t*), uint32_t nof_rx_antennas, void *stream_handler, int decimate) { int ret = SRSLTE_ERROR_INVALID_INPUTS; if (q != NULL && stream_handler != NULL && srslte_nofprb_isvalid(cell.nof_prb) && nof_rx_antennas <= SRSLTE_MAX_PORTS && recv_callback != NULL) { ret = SRSLTE_ERROR; //int decimate = q->decimate; bzero(q, sizeof(srslte_ue_sync_t)); q->decimate = decimate; q->stream = stream_handler; q->recv_callback = recv_callback; q->nof_rx_antennas = nof_rx_antennas; q->cell = cell; q->fft_size = srslte_symbol_sz(q->cell.nof_prb); q->sf_len = SRSLTE_SF_LEN(q->fft_size); q->file_mode = false; q->correct_cfo = true; q->agc_period = 0; q->sample_offset_correct_period = DEFAULT_SAMPLE_OFFSET_CORRECT_PERIOD; q->sfo_ema = DEFAULT_SFO_EMA_COEFF; if (cell.id == 1000) { /* If the cell is unkown, we search PSS/SSS in 5 ms */ q->nof_recv_sf = 5; q->decode_sss_on_track = true; } else { /* If the cell is known, we work on a 1ms basis */ q->nof_recv_sf = 1; q->decode_sss_on_track = true; } q->frame_len = q->nof_recv_sf*q->sf_len; if(q->fft_size < 700 && q->decimate) { q->decimate = 1; } if(srslte_sync_init_decim(&q->sfind, q->frame_len, q->frame_len, q->fft_size,q->decimate)) { fprintf(stderr, "Error initiating sync find\n"); goto clean_exit; } if (cell.id == 1000) { if(srslte_sync_init(&q->strack, q->frame_len, TRACK_FRAME_SIZE, q->fft_size)) { fprintf(stderr, "Error initiating sync track\n"); goto clean_exit; } } else { if(srslte_sync_init(&q->strack, q->frame_len, SRSLTE_CP_LEN_NORM(1,q->fft_size), q->fft_size)) { fprintf(stderr, "Error initiating sync track\n"); goto clean_exit; } } if (cell.id == 1000) { /* If the cell id is unknown, enable CP detection on find */ // FIXME: CP detection not working very well. Not supporting Extended CP right now srslte_sync_cp_en(&q->sfind, false); srslte_sync_cp_en(&q->strack, false); srslte_sync_set_cfo_ema_alpha(&q->sfind, 0.8); srslte_sync_set_cfo_ema_alpha(&q->strack, 0.1); srslte_sync_cfo_i_detec_en(&q->sfind, false); q->nof_avg_find_frames = FIND_NOF_AVG_FRAMES; srslte_sync_set_threshold(&q->sfind, 2.0); srslte_sync_set_threshold(&q->strack, 1.2); } else { srslte_sync_set_N_id_2(&q->sfind, cell.id%3); srslte_sync_set_N_id_2(&q->strack, cell.id%3); q->sfind.cp = cell.cp; q->strack.cp = cell.cp; srslte_sync_cp_en(&q->sfind, false); srslte_sync_cp_en(&q->strack, false); srslte_sync_cfo_i_detec_en(&q->sfind, false); srslte_sync_set_cfo_ema_alpha(&q->sfind, 0.1); srslte_sync_set_cfo_ema_alpha(&q->strack, 0.1); /* In find phase and if the cell is known, do not average pss correlation * because we only capture 1 subframe and do not know where the peak is. */ q->nof_avg_find_frames = 1; srslte_sync_set_em_alpha(&q->sfind, 1); srslte_sync_set_threshold(&q->sfind, 3.0); srslte_sync_set_em_alpha(&q->strack, 0.2); srslte_sync_set_threshold(&q->strack, 1.2); } srslte_ue_sync_reset(q); ret = SRSLTE_SUCCESS; } clean_exit: if (ret == SRSLTE_ERROR) { srslte_ue_sync_free(q); } return ret; } uint32_t srslte_ue_sync_sf_len(srslte_ue_sync_t *q) { return q->frame_len; } void srslte_ue_sync_free(srslte_ue_sync_t *q) { if (q->do_agc) { srslte_agc_free(&q->agc); } if (!q->file_mode) { srslte_sync_free(&q->sfind); srslte_sync_free(&q->strack); } else { srslte_filesource_free(&q->file_source); } bzero(q, sizeof(srslte_ue_sync_t)); } void srslte_ue_sync_get_last_timestamp(srslte_ue_sync_t *q, srslte_timestamp_t *timestamp) { memcpy(timestamp, &q->last_timestamp, sizeof(srslte_timestamp_t)); } uint32_t srslte_ue_sync_peak_idx(srslte_ue_sync_t *q) { return q->peak_idx; } srslte_ue_sync_state_t srslte_ue_sync_get_state(srslte_ue_sync_t *q) { return q->state; } uint32_t srslte_ue_sync_get_sfidx(srslte_ue_sync_t *q) { return q->sf_idx; } void srslte_ue_sync_cfo_i_detec_en(srslte_ue_sync_t *q, bool enable) { srslte_sync_cfo_i_detec_en(&q->strack, enable); srslte_sync_cfo_i_detec_en(&q->sfind, enable); } float srslte_ue_sync_get_cfo(srslte_ue_sync_t *q) { return 15000 * srslte_sync_get_cfo(&q->strack); } void srslte_ue_sync_set_cfo(srslte_ue_sync_t *q, float cfo) { srslte_sync_set_cfo(&q->sfind, cfo/15000); srslte_sync_set_cfo(&q->strack, cfo/15000); } float srslte_ue_sync_get_sfo(srslte_ue_sync_t *q) { return q->mean_sfo/5e-3; } int srslte_ue_sync_get_last_sample_offset(srslte_ue_sync_t *q) { return q->last_sample_offset; } void srslte_ue_sync_set_sample_offset_correct_period(srslte_ue_sync_t *q, uint32_t nof_subframes) { q->sample_offset_correct_period = nof_subframes; } void srslte_ue_sync_set_sfo_ema(srslte_ue_sync_t *q, float ema_coefficient) { q->sfo_ema = ema_coefficient; } void srslte_ue_sync_decode_sss_on_track(srslte_ue_sync_t *q, bool enabled) { q->decode_sss_on_track = enabled; } void srslte_ue_sync_set_N_id_2(srslte_ue_sync_t *q, uint32_t N_id_2) { if (!q->file_mode) { srslte_ue_sync_reset(q); srslte_sync_set_N_id_2(&q->strack, N_id_2); srslte_sync_set_N_id_2(&q->sfind, N_id_2); } } void srslte_ue_sync_set_agc_period(srslte_ue_sync_t *q, uint32_t period) { q->agc_period = period; } static int find_peak_ok(srslte_ue_sync_t *q, cf_t *input_buffer[SRSLTE_MAX_PORTS]) { if (srslte_sync_sss_detected(&q->sfind)) { /* Get the subframe index (0 or 5) */ q->sf_idx = srslte_sync_get_sf_idx(&q->sfind) + q->nof_recv_sf; } else { DEBUG("Found peak at %d, SSS not detected\n", q->peak_idx); } q->frame_find_cnt++; DEBUG("Found peak %d at %d, value %.3f, Cell_id: %d CP: %s\n", q->frame_find_cnt, q->peak_idx, srslte_sync_get_last_peak_value(&q->sfind), q->cell.id, srslte_cp_string(q->cell.cp)); if (q->frame_find_cnt >= q->nof_avg_find_frames || q->peak_idx < 2*q->fft_size) { INFO("Realigning frame, reading %d samples\n", q->peak_idx+q->sf_len/2); /* Receive the rest of the subframe so that we are subframe aligned */ if (q->recv_callback(q->stream, input_buffer, q->peak_idx+q->sf_len/2, &q->last_timestamp) < 0) { return SRSLTE_ERROR; } /* Reset variables */ q->frame_ok_cnt = 0; q->frame_no_cnt = 0; q->frame_total_cnt = 0; q->frame_find_cnt = 0; q->mean_sample_offset = 0; /* Goto Tracking state */ q->state = SF_TRACK; /* Initialize track state CFO */ q->strack.mean_cfo = q->sfind.mean_cfo; q->strack.cfo_i = q->sfind.cfo_i; } return 0; } static int track_peak_ok(srslte_ue_sync_t *q, uint32_t track_idx) { /* Make sure subframe idx is what we expect */ if ((q->sf_idx != srslte_sync_get_sf_idx(&q->strack)) && q->decode_sss_on_track && srslte_sync_sss_detected(&q->strack)) { INFO("Warning: Expected SF idx %d but got %d! (%d frames)\n", q->sf_idx, srslte_sync_get_sf_idx(&q->strack), q->frame_no_cnt); q->frame_no_cnt++; if (q->frame_no_cnt >= TRACK_MAX_LOST) { INFO("\n%d frames lost. Going back to FIND\n", (int) q->frame_no_cnt); q->state = SF_FIND; } } else { q->frame_no_cnt = 0; } // Get sampling time offset q->last_sample_offset = ((int) track_idx - (int) q->strack.max_offset/2 - (int) q->strack.fft_size); // Adjust sampling time every q->sample_offset_correct_period subframes uint32_t frame_idx = 0; if (q->sample_offset_correct_period) { frame_idx = q->frame_ok_cnt%q->sample_offset_correct_period; q->mean_sample_offset += (float) q->last_sample_offset/q->sample_offset_correct_period; } else { q->mean_sample_offset = q->last_sample_offset; } // Compute cumulative moving average time offset */ if (!frame_idx) { // Adjust RF sampling time based on the mean sampling offset q->next_rf_sample_offset = (int) round(q->mean_sample_offset); // Reset PSS averaging if correcting every a period longer than 1 if (q->sample_offset_correct_period > 1) { srslte_sync_reset(&q->strack); } // Compute SFO based on mean sample offset if (q->sample_offset_correct_period) { q->mean_sample_offset /= q->sample_offset_correct_period; } q->mean_sfo = SRSLTE_VEC_EMA(q->mean_sample_offset, q->mean_sfo, q->sfo_ema); if (q->next_rf_sample_offset) { INFO("Time offset adjustment: %d samples (%.2f), mean SFO: %.2f Hz, %.5f samples/5-sf, ema=%f, length=%d\n", q->next_rf_sample_offset, q->mean_sample_offset, srslte_ue_sync_get_sfo(q), q->mean_sfo, q->sfo_ema, q->sample_offset_correct_period); } q->mean_sample_offset = 0; } /* If the PSS peak is beyond the frame (we sample too slowly), discard the offseted samples to align next frame */ if (q->next_rf_sample_offset > 0 && q->next_rf_sample_offset < MAX_TIME_OFFSET) { DEBUG("Positive time offset %d samples.\n", q->next_rf_sample_offset); if (q->recv_callback(q->stream, dummy_offset_buffer, (uint32_t) q->next_rf_sample_offset, &q->last_timestamp) < 0) { fprintf(stderr, "Error receiving from USRP\n"); return SRSLTE_ERROR; } q->next_rf_sample_offset = 0; } q->peak_idx = q->sf_len/2 + q->last_sample_offset; q->frame_ok_cnt++; return 1; } static int track_peak_no(srslte_ue_sync_t *q) { /* if we missed too many PSS go back to FIND and consider this frame unsynchronized */ q->frame_no_cnt++; if (q->frame_no_cnt >= TRACK_MAX_LOST) { INFO("\n%d frames lost. Going back to FIND\n", (int) q->frame_no_cnt); q->state = SF_FIND; return 0; } else { INFO("Tracking peak not found. Peak %.3f, %d lost\n", srslte_sync_get_last_peak_value(&q->strack), (int) q->frame_no_cnt); /* printf("Saving files: pss_corr (%d), input (%d)\n", q->strack.pss.frame_size, SRSLTE_SF_LEN_PRB(q->cell.nof_prb)); srslte_vec_save_file("pss_corr", q->strack.pss.conv_output_avg, q->strack.pss.frame_size*sizeof(float)); srslte_vec_save_file("input", q->input_buffer, SRSLTE_SF_LEN_PRB(q->cell.nof_prb)*sizeof(cf_t)); exit(-1); */ return 1; } } static int receive_samples(srslte_ue_sync_t *q, cf_t *input_buffer[SRSLTE_MAX_PORTS]) { /* A negative time offset means there are samples in our buffer for the next subframe, because we are sampling too fast. */ if (q->next_rf_sample_offset < 0) { q->next_rf_sample_offset = -q->next_rf_sample_offset; } /* Get N subframes from the USRP getting more samples and keeping the previous samples, if any */ cf_t *ptr[SRSLTE_MAX_PORTS]; for (int i=0;inof_rx_antennas;i++) { ptr[i] = &input_buffer[i][q->next_rf_sample_offset]; } if (q->recv_callback(q->stream, ptr, q->frame_len - q->next_rf_sample_offset, &q->last_timestamp) < 0) { return SRSLTE_ERROR; } /* reset time offset */ q->next_rf_sample_offset = 0; return SRSLTE_SUCCESS; } bool first_track = true; int srslte_ue_sync_zerocopy(srslte_ue_sync_t *q, cf_t *input_buffer) { cf_t *_input_buffer[SRSLTE_MAX_PORTS]; _input_buffer[0] = input_buffer; return srslte_ue_sync_zerocopy_multi(q, _input_buffer); } /* Returns 1 if the subframe is synchronized in time, 0 otherwise */ int srslte_ue_sync_zerocopy_multi(srslte_ue_sync_t *q, cf_t *input_buffer[SRSLTE_MAX_PORTS]) { int ret = SRSLTE_ERROR_INVALID_INPUTS; uint32_t track_idx; if (q != NULL && input_buffer != NULL) { if (q->file_mode) { int n = srslte_filesource_read(&q->file_source, input_buffer[0], q->sf_len); if (n < 0) { fprintf(stderr, "Error reading input file\n"); return SRSLTE_ERROR; } if (n == 0) { srslte_filesource_seek(&q->file_source, 0); q->sf_idx = 9; int n = srslte_filesource_read(&q->file_source, input_buffer[0], q->sf_len); if (n < 0) { fprintf(stderr, "Error reading input file\n"); return SRSLTE_ERROR; } } if (q->correct_cfo) { srslte_cfo_correct(&q->file_cfo_correct, input_buffer[0], input_buffer[0], q->file_cfo / 15000 / q->fft_size); } q->sf_idx++; if (q->sf_idx == 10) { q->sf_idx = 0; } INFO("Reading %d samples. sf_idx = %d\n", q->sf_len, q->sf_idx); ret = 1; } else { if (receive_samples(q, input_buffer)) { fprintf(stderr, "Error receiving samples\n"); return SRSLTE_ERROR; } switch (q->state) { case SF_FIND: switch(srslte_sync_find(&q->sfind, input_buffer[0], 0, &q->peak_idx)) { case SRSLTE_SYNC_ERROR: ret = SRSLTE_ERROR; fprintf(stderr, "Error finding correlation peak (%d)\n", ret); return SRSLTE_ERROR; case SRSLTE_SYNC_FOUND: ret = find_peak_ok(q, input_buffer); break; case SRSLTE_SYNC_FOUND_NOSPACE: /* If a peak was found but there is not enough space for SSS/CP detection, discard a few samples */ INFO("No space for SSS/CP detection. Realigning frame...\n",0); q->recv_callback(q->stream, dummy_offset_buffer, q->frame_len/2, NULL); srslte_sync_reset(&q->sfind); ret = SRSLTE_SUCCESS; break; default: ret = SRSLTE_SUCCESS; break; } if (q->do_agc) { srslte_agc_process(&q->agc, input_buffer[0], q->sf_len); } break; case SF_TRACK: ret = 1; srslte_sync_sss_en(&q->strack, q->decode_sss_on_track); q->sf_idx = (q->sf_idx + q->nof_recv_sf) % 10; /* Every SF idx 0 and 5, find peak around known position q->peak_idx */ if (q->sf_idx == 0 || q->sf_idx == 5) { if (q->do_agc && (q->agc_period == 0 || (q->agc_period && (q->frame_total_cnt%q->agc_period) == 0))) { srslte_agc_process(&q->agc, input_buffer[0], q->sf_len); } #ifdef MEASURE_EXEC_TIME struct timeval t[3]; gettimeofday(&t[1], NULL); #endif track_idx = 0; /* Track PSS/SSS around the expected PSS position * In tracking phase, the subframe carrying the PSS is always the last one of the frame */ switch(srslte_sync_find(&q->strack, input_buffer[0], q->frame_len - q->sf_len/2 - q->fft_size - q->strack.max_offset/2, &track_idx)) { case SRSLTE_SYNC_ERROR: ret = SRSLTE_ERROR; fprintf(stderr, "Error tracking correlation peak\n"); return SRSLTE_ERROR; case SRSLTE_SYNC_FOUND: ret = track_peak_ok(q, track_idx); break; case SRSLTE_SYNC_FOUND_NOSPACE: // It's very very unlikely that we fall here because this event should happen at FIND phase only ret = 0; q->state = SF_FIND; printf("Warning: No space for SSS/CP while in tracking phase\n"); break; case SRSLTE_SYNC_NOFOUND: ret = track_peak_no(q); break; } #ifdef MEASURE_EXEC_TIME gettimeofday(&t[2], NULL); get_time_interval(t); q->mean_exec_time = (float) SRSLTE_VEC_CMA((float) t[0].tv_usec, q->mean_exec_time, q->frame_total_cnt); #endif if (ret == SRSLTE_ERROR) { fprintf(stderr, "Error processing tracking peak\n"); q->state = SF_FIND; return SRSLTE_SUCCESS; } q->frame_total_cnt++; } if (q->correct_cfo) { for (int i=0;inof_rx_antennas;i++) { srslte_cfo_correct(&q->sfind.cfocorr, input_buffer[i], input_buffer[i], -srslte_sync_get_cfo(&q->strack) / q->fft_size); } } break; } } } return ret; } void srslte_ue_sync_reset(srslte_ue_sync_t *q) { if (!q->file_mode) { srslte_sync_reset(&q->sfind); srslte_sync_reset(&q->strack); } else { q->sf_idx = 9; } q->state = SF_FIND; q->frame_ok_cnt = 0; q->frame_no_cnt = 0; q->frame_total_cnt = 0; q->mean_sample_offset = 0.0; q->next_rf_sample_offset = 0; q->frame_find_cnt = 0; #ifdef MEASURE_EXEC_TIME q->mean_exec_time = 0; #endif }