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Radio: fix frame overlap at start-of-burst

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master
Xavier Arteaga 4 years ago committed by Xavier Arteaga
parent a5f9ea5654
commit eba20b6367
1 changed files with 56 additions and 51 deletions
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107
lib/src/radio/radio.cc
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@ -446,9 +446,9 @@ bool radio::open_dev(const uint32_t& device_idx, const std::string& device_name,
} }
srslte::console("Opening %d channels in RF device=%s with args=%s\n", srslte::console("Opening %d channels in RF device=%s with args=%s\n",
nof_channels_x_dev, nof_channels_x_dev,
dev_name ? dev_name : "default", dev_name ? dev_name : "default",
dev_args ? dev_args : "default"); dev_args ? dev_args : "default");
if (srslte_rf_open_devname(rf_device, dev_name, dev_args, nof_channels_x_dev)) { if (srslte_rf_open_devname(rf_device, dev_name, dev_args, nof_channels_x_dev)) {
log_h->error("Error opening RF device\n"); log_h->error("Error opening RF device\n");
@ -486,58 +486,63 @@ bool radio::tx_dev(const uint32_t& device_idx, rf_buffer_interface& buffer, cons
srslte_timestamp_add(&tx_time, 0, tx_adv_sec); srslte_timestamp_add(&tx_time, 0, tx_adv_sec);
} }
// Calculate transmission overlap/gap if it is not start of the burst // Calculates transmission time overlap with previous transmission
if (not is_start_of_burst) { srslte_timestamp_t ts_overlap = end_of_burst_time[device_idx];
// Calculates transmission time overlap with previous transmission srslte_timestamp_sub(&ts_overlap, tx_time.full_secs, tx_time.frac_secs);
srslte_timestamp_t ts_overlap = end_of_burst_time[device_idx];
srslte_timestamp_sub(&ts_overlap, tx_time.full_secs, tx_time.frac_secs);
// Calculates number of overlap samples with previous transmission // Calculates number of overlap samples with previous transmission
int32_t past_nsamples = (int32_t)round(cur_tx_srate * srslte_timestamp_real(&ts_overlap)); int32_t past_nsamples = (int32_t)round(cur_tx_srate * srslte_timestamp_real(&ts_overlap));
// if past_nsamples is positive, the current transmission overlaps with the previous transmission. If it is negative // if past_nsamples is positive, the current transmission overlaps with the previous transmission. If it is negative
// there is a gap between the previous transmission and the current transmission. // there is a gap between the previous transmission and the current transmission.
if (past_nsamples > 0) { if (past_nsamples > 0) {
// If the overlap length is greater than the current transmission length, it means the whole transmission is in // If the overlap length is greater than the current transmission length, it means the whole transmission is in
// the past and it shall be ignored // the past and it shall be ignored
if ((int32_t)nof_samples < past_nsamples) { if ((int32_t)nof_samples < past_nsamples) {
return true; return true;
} }
// Trim the first past_nsamples
sample_offset = (uint32_t)past_nsamples; // Sets an offset for moving first samples offset
tx_time = end_of_burst_time[device_idx]; // Keeps same transmission time
nof_samples = nof_samples - past_nsamples; // Subtracts the number of trimmed samples
} else if (past_nsamples < 0) { // Trim the first past_nsamples
// if the gap is bigger than TX_MAX_GAP_ZEROS, stop burst sample_offset = (uint32_t)past_nsamples; // Sets an offset for moving first samples offset
if (fabs(srslte_timestamp_real(&ts_overlap)) > tx_max_gap_zeros) { tx_time = end_of_burst_time[device_idx]; // Keeps same transmission time
tx_end(); nof_samples = nof_samples - past_nsamples; // Subtracts the number of trimmed samples
} else {
// Otherwise, transmit zeros // Prints discarded samples
uint32_t gap_nsamples = abs(past_nsamples); log_h->debug("Detected RF overlap of %.1f us. Discarding %d samples. Power=%+.1f dBfs\n",
while (gap_nsamples > 0) { srslte_timestamp_real(&ts_overlap) * 1.0e6,
// Transmission cannot exceed SRSLTE_SF_LEN_MAX (zeros buffer size limitation) past_nsamples,
uint32_t nzeros = SRSLTE_MIN(gap_nsamples, SRSLTE_SF_LEN_MAX); srslte_convert_power_to_dB(srslte_vec_avg_power_cf(&buffer.get(0)[nof_samples], past_nsamples)));
// Zeros transmission } else if (past_nsamples < 0 and not is_start_of_burst) {
int ret = srslte_rf_send_timed2(rf_device, // if the gap is bigger than TX_MAX_GAP_ZEROS, stop burst
zeros, if (fabs(srslte_timestamp_real(&ts_overlap)) > tx_max_gap_zeros) {
nzeros, log_h->info("Detected RF gap of %.1f us. Sending end-of-burst.\n", srslte_timestamp_real(&ts_overlap) * 1.0e6);
end_of_burst_time[device_idx].full_secs, tx_end();
end_of_burst_time[device_idx].frac_secs, } else {
false, log_h->debug("Detected RF gap of %.1f us. Tx'ing zeroes.\n", srslte_timestamp_real(&ts_overlap) * 1.0e6);
false); // Otherwise, transmit zeros
if (ret < SRSLTE_SUCCESS) { uint32_t gap_nsamples = abs(past_nsamples);
return false; while (gap_nsamples > 0) {
} // Transmission cannot exceed SRSLTE_SF_LEN_MAX (zeros buffer size limitation)
uint32_t nzeros = SRSLTE_MIN(gap_nsamples, SRSLTE_SF_LEN_MAX);
// Substract gap samples
gap_nsamples -= nzeros; // Zeros transmission
int ret = srslte_rf_send_timed2(rf_device,
// Increase timestamp zeros,
srslte_timestamp_add(&end_of_burst_time[device_idx], 0, (double)nzeros / cur_tx_srate); nzeros,
end_of_burst_time[device_idx].full_secs,
end_of_burst_time[device_idx].frac_secs,
false,
false);
if (ret < SRSLTE_SUCCESS) {
return false;
} }
// Substract gap samples
gap_nsamples -= nzeros;
// Increase timestamp
srslte_timestamp_add(&end_of_burst_time[device_idx], 0, (double)nzeros / cur_tx_srate);
} }
} }
} }

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