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openairinterface5g/openair1/PHY/NR_TRANSPORT/nr_prach.c
T
Sakthivel Velumani 5b92859cce phy: remove function pointers in frame param 
1. Removed function pointers for functions get_samples_per_slot(),
   get_samples_slot_timestamp() and get_slot_from_timestamp() as it does
   not offer any advantage. The functions are now called directly from
   everywhere.
2. Optimized these functions by removing loops where ever possible.
2025-12-10 23:25:24 +00:00

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/*
* Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The OpenAirInterface Software Alliance licenses this file to You under
* the OAI Public License, Version 1.1 (the "License"); you may not use this file
* except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.openairinterface.org/?page_id=698
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*-------------------------------------------------------------------------------
* For more information about the OpenAirInterface (OAI) Software Alliance:
* contact@openairinterface.org
*/
/*! \file PHY/NR_TRANSPORT/nr_prach.c
* \brief Top-level routines for generating and decoding the PRACH physical channel V15.4 2018-12
* \author R. Knopp
* \date 2019
* \version 0.1
* \company Eurecom
* \email: knopp@eurecom.fr
* \note
* \warning
*/
#include "PHY/defs_gNB.h"
#include "SCHED_NR/sched_nr.h"
#include "PHY/NR_TRANSPORT/nr_transport_proto.h"
#include "PHY/NR_TRANSPORT/nr_transport_common_proto.h"
#include "openair1/PHY/NR_TRANSPORT/nr_prach.h"
void init_prach_list(prach_list_t *l)
{
pthread_mutex_init(&l->prach_list_mutex, NULL);
for (prach_item_t *p = l->list; p < l->list + NUMBER_OF_NR_PRACH_MAX; p++)
*p = (prach_item_t){.frame = -1, .slot = -1};
}
void free_nr_prach_entry(prach_list_t *l, prach_item_t *p)
{
pthread_mutex_lock(&l->prach_list_mutex);
if (p->frame == -1)
LOG_E(NR_PHY_RACH, "Freeing a not allocated prach entry\n");
*p = (prach_item_t){.frame = -1, .slot = -1, .num_slots = -1};
pthread_mutex_unlock(&l->prach_list_mutex);
}
prach_item_t *find_nr_prach(prach_list_t *l, int frame, int slot, find_type_t type)
{
pthread_mutex_lock(&l->prach_list_mutex);
prach_item_t *p = l->list;
prach_item_t *end = p + NUMBER_OF_NR_PRACH_MAX;
for (; p < end; p++)
if (p->frame == frame && (p->slot + p->num_slots - 1) == slot)
break;
if (p == end) {
if (type == SEARCH_EXIST) {
pthread_mutex_unlock(&l->prach_list_mutex);
return NULL;
}
for (p = l->list; p < end; p++)
if (p->frame == -1 && p->slot == -1)
break;
}
if (p == end) {
pthread_mutex_unlock(&l->prach_list_mutex);
return NULL;
}
// mark it used, it will be filled later
p->frame = frame;
pthread_mutex_unlock(&l->prach_list_mutex);
return p;
}
prach_item_t *nr_schedule_rx_prach(PHY_VARS_gNB *gNB, int SFN, int Slot, nfapi_nr_prach_pdu_t *prach_pdu)
{
prach_item_t *prach = find_nr_prach(&gNB->prach_list, SFN, Slot, SEARCH_EXIST_OR_FREE);
if (!prach) {
LOG_W(PHY, "no free space for a new detected rach, discarding\n");
return NULL;
}
const int fmt = prach_pdu->prach_format;
NR_DL_FRAME_PARMS *fp = &gNB->frame_parms;
// we set only elements as the whole structure has been cleaned when we release it
prach->frame = SFN;
prach->slot = Slot;
prach->num_slots = fmt < 4 ? get_long_prach_dur(fmt, fp->numerology_index) : 1;
if (gNB->common_vars.beam_id) {
int n_symb = get_nr_prach_duration(prach_pdu->prach_format);
AssertFatal(prach_pdu->beamforming.dig_bf_interface < NFAPI_MAX_NUM_BG_IF,
"impossible beams size %d\n",
prach_pdu->beamforming.dig_bf_interface);
for (int i = 0; i < prach_pdu->beamforming.dig_bf_interface; i++) {
int fapi_beam_idx = prach_pdu->beamforming.prgs_list[0].dig_bf_interface_list[i].beam_idx;
int start_symb = prach_pdu->prach_start_symbol + i * n_symb;
int bitmap = SL_to_bitmap(start_symb, n_symb);
prach->beams[i] = beam_index_allocation(gNB->enable_analog_das,
fapi_beam_idx,
&gNB->gNB_config.analog_beamforming_ve,
&gNB->common_vars,
Slot,
NR_NUMBER_OF_SYMBOLS_PER_SLOT,
bitmap);
}
}
prach->pdu = *prach_pdu;
nfapi_nr_prach_config_t *cfg = &gNB->gNB_config.prach_config;
nfapi_nr_num_prach_fd_occasions_t *occ = &cfg->num_prach_fd_occasions_list[prach_pdu->num_ra];
prach->rootSequenceIndex = occ->prach_root_sequence_index.value;
prach->numrootSequenceIndex = occ->num_root_sequences.value;
prach->msg1_frequencystart = occ->k1.value;
prach->mu = cfg->prach_sub_c_spacing.value;
prach->prach_sequence_length = cfg->prach_sequence_length.value;
prach->restricted_set = cfg->restricted_set_config.value;
prach->numerology_index = fp->numerology_index;
prach->nb_rx = gNB->gNB_config.carrier_config.num_rx_ant.value;
prach->Xu = gNB->X_u;
prach->rx_prach = &gNB->rx_prach;
return prach;
}
static void rx_nr_prach_ru_internal(prach_item_t *p,
int beam_id,
int prachStartSymbol,
int prachOccasion,
int32_t **rxdata,
NR_DL_FRAME_PARMS *fp,
int N_TA_offset)
{
int sample_offset_slot;
const int sum = fp->ofdm_symbol_size + fp->nb_prefix_samples;
const int sum0 = fp->ofdm_symbol_size + fp->nb_prefix_samples0;
if (prachStartSymbol == 0) {
sample_offset_slot = 0;
} else if (fp->slots_per_subframe == 1) {
if (prachStartSymbol <= 7)
sample_offset_slot = sum * (prachStartSymbol - 1) + sum0;
else
sample_offset_slot = sum * (prachStartSymbol - 2) + sum0 * 2;
} else {
if (!(p->slot % (fp->slots_per_subframe / 2)))
sample_offset_slot = sum * (prachStartSymbol - 1) + sum0;
else
sample_offset_slot = sum * prachStartSymbol;
}
LOG_D(PHY,
"frame %d, slot %d: doing rx_nr_prach_ru for format %d, numRA %d, prachStartSymbol %d, prachOccasion %d\n",
p->frame,
p->slot,
p->pdu.prach_format,
p->pdu.num_ra,
prachStartSymbol,
prachOccasion);
int reps;
int Ncp;
int dftlen;
int mu = p->numerology_index;
if (p->prach_sequence_length == 0) {
LOG_D(PHY,
"PRACH in %d.%d, format %d, msg1_frequencyStart %d\n",
p->frame,
p->slot,
p->pdu.prach_format,
p->msg1_frequencystart);
switch (p->pdu.prach_format) {
case 0:
reps = 1;
Ncp = 3168;
dftlen = 24576;
break;
case 1:
reps = 2;
Ncp = 21024;
dftlen = 24576;
break;
case 2:
reps = 4;
Ncp = 4688;
dftlen = 24576;
break;
case 3:
reps = 4;
Ncp = 3168;
dftlen = 6144;
break;
default:
AssertFatal(1 == 0, "Illegal prach format %d for length 839\n", p->pdu.prach_format);
break;
}
} else {
LOG_D(PHY,
"PRACH in %d.%d, format %s, msg1_frequencyStart %d,startSymbol %d\n",
p->frame,
p->slot,
prachfmt[p->pdu.prach_format],
p->msg1_frequencystart,
prachStartSymbol);
switch (p->pdu.prach_format) {
case 4: // A1
reps = 2;
Ncp = 288 >> mu;
break;
case 5: // A2
reps = 4;
Ncp = 576 >> mu;
break;
case 6: // A3
reps = 6;
Ncp = 864 >> mu;
break;
case 7: // B1
reps = 2;
Ncp = 216 >> mu;
break;
/*
// B2 and B3 do not exist in FAPI
case 4: //B2
reps = 4;
Ncp = 360 >> mu;
break;
case 5: //B3
reps = 6;
Ncp = 504 >> mu;
break;
*/
case 8: // B4
reps = 12;
Ncp = 936 >> mu;
break;
case 9: // C0
reps = 1;
Ncp = 1240 >> mu;
break;
case 10: // C2
reps = 4;
Ncp = 2048 >> mu;
break;
default:
AssertFatal(1 == 0, "unknown prach format %x\n", p->pdu.prach_format);
break;
}
dftlen = 2048 >> mu;
}
//actually what we should be checking here is how often the current prach crosses a 0.5ms boundary.
//I am not quite sure for which paramter set this would be the case,
//so I will ignore it for now and just check if the prach starts on a 0.5ms boundary
if (p->numerology_index == 0) {
if (prachStartSymbol == 0 || prachStartSymbol == 7)
Ncp += 16;
} else {
if (p->slot % (fp->slots_per_subframe / 2) == 0 && prachStartSymbol == 0)
Ncp += 16;
}
switch(fp->samples_per_subframe) {
case 7680:
// 5 MHz @ 7.68 Ms/s
Ncp >>= 2;
dftlen >>= 2;
break;
case 15360:
// 10, 15 MHz @ 15.36 Ms/s
Ncp >>= 1;
dftlen >>= 1;
break;
case 23040:
// 20 MHz @ 23.04 Ms/s
Ncp = (Ncp * 3) / 4;
dftlen = (dftlen * 3) / 4;
break;
case 30720:
// 20, 25, 30 MHz @ 30.72 Ms/s
break;
case 46080:
// 40 MHz @ 46.08 Ms/s
Ncp = (Ncp*3)/2;
dftlen = (dftlen*3)/2;
break;
case 61440:
// 40, 50, 60 MHz @ 61.44 Ms/s
Ncp <<= 1;
dftlen <<= 1;
break;
case 92160:
// 50, 60, 70, 80, 90 MHz @ 92.16 Ms/s
Ncp *= 3;
dftlen *= 3;
break;
case 122880:
// 70, 80, 90, 100 MHz @ 122.88 Ms/s
Ncp <<= 2;
dftlen <<= 2;
break;
case 184320:
// 100 MHz @ 184.32 Ms/s
Ncp = Ncp*6;
dftlen = dftlen*6;
break;
case 245760:
// 200 MHz @ 245.76 Ms/s
Ncp <<= 3;
dftlen <<= 3;
break;
default:
AssertFatal(1==0,"sample rate %f MHz not supported for numerology %d\n", fp->samples_per_subframe / 1000.0, mu);
}
const dft_size_idx_t dftsize = get_dft(dftlen);
// Do forward transform
if (LOG_DEBUGFLAG(DEBUG_PRACH)) {
LOG_D(PHY, "rx_prach: Doing PRACH FFT for nb_rx:%d Ncp:%d dftlen:%d\n", p->nb_rx, Ncp, dftlen);
}
const unsigned int K = get_prach_K(p->prach_sequence_length, p->pdu.prach_format, p->numerology_index, p->mu);
const uint8_t kbar = get_PRACH_k_bar(p->mu, p->numerology_index);
int n_ra_prb = p->msg1_frequencystart;
int k = (12*n_ra_prb) - 6*fp->N_RB_UL;
int N_ZC = (p->prach_sequence_length == 0) ? 839 : 139;
if (k<0) k+=(fp->ofdm_symbol_size);
k*=K;
k+=kbar;
for (int aa = 0; aa < p->nb_rx; aa++) {
// Fixme: slot or slot makes no sense ???
int slot2 = p->prach_sequence_length ? p->slot : p->slot;
int idx = aa + beam_id * p->nb_rx;
c16_t *prach = (c16_t *)&rxdata[idx][get_samples_slot_timestamp(fp, slot2) + sample_offset_slot - N_TA_offset];
// do DFT
c16_t *prach2 = prach + Ncp;
c16_t rxsigF_tmp[N_ZC];
memset(rxsigF_tmp, 0, sizeof(rxsigF_tmp));
for (int i = 0; i < reps; i++, prach2 += dftlen) {
c16_t tmp[dftlen] __attribute__((aligned(32)));
dft(dftsize, (int16_t *)prach2, (int16_t *)tmp, 1);
// Coherent combining of PRACH repetitions (assumes channel does not change, to be revisted for "long" PRACH)
LOG_D(PHY, "Doing PRACH combining of %d reptitions N_ZC %d\n", reps, N_ZC);
// if (k+N_ZC > dftlen) { // PRACH signal is split around DC
int k2 = k;
for (int j = 0; j < N_ZC; j++, k2++) {
if (k2 == dftlen)
k2 = 0;
rxsigF_tmp[j] = c16add(rxsigF_tmp[j], tmp[k2]);
}
}
memcpy(p->rxsigF[prachOccasion][aa], rxsigF_tmp, sizeof(rxsigF_tmp));
}
}
void rx_nr_prach_ru(prach_item_t *p, int32_t **rxdata, NR_DL_FRAME_PARMS *fp, int N_TA_offset)
{
int N_dur = get_nr_prach_duration(p->pdu.prach_format);
LOG_D(NR_PHY_RACH, "%d.%d try to decode %d occasions \n", p->frame, p->slot, p->pdu.num_prach_ocas);
for (int prach_oc = 0; prach_oc < p->pdu.num_prach_ocas; prach_oc++) {
int prachStartSymbol = p->pdu.prach_start_symbol + prach_oc * N_dur;
int beam_id = p->beams[prach_oc];
// comment FK: the standard 38.211 section 5.3.2 has one extra term +14*N_RA_slot. This is because there prachStartSymbol is
// given wrt to start of the 15kHz slot or 60kHz slot. Here we work slot based, so this function is anyway only called in slots
// where there is PRACH. Its up to the MAC to schedule another PRACH PDU in the case there are there N_RA_slot \in {0,1}.
rx_nr_prach_ru_internal(p, beam_id, prachStartSymbol, prach_oc, rxdata, fp, N_TA_offset);
}
}
rx_prach_out_t rx_nr_prach(const prach_item_t *in, int occasion)
{
rx_prach_out_t out = {};
uint16_t preamble_index0 = 0;
uint16_t numshift = 0;
int first_nonzero_root_idx = 0;
bool new_dft = false;
int log2_ifft_size = 10;
const int nb_rx = in->nb_rx;
const int NCS = in->pdu.num_cs;
const int prach_fmt = in->pdu.prach_format;
const int N_ZC = in->prach_sequence_length == 0 ? 839 : 139;
LOG_D(NR_PHY_RACH,
"L1 PRACH RX: rooSequenceIndex %d, numRootSeqeuences %d, NCS %d, N_ZC %d, format %d \n",
in->rootSequenceIndex,
in->numrootSequenceIndex,
NCS,
N_ZC,
prach_fmt);
if (LOG_DEBUGFLAG(DEBUG_PRACH)) {
if ((in->frame & 1023) < 20)
LOG_D(PHY, "PRACH (gNB) : running rx_prach for slot %d, rootSequenceIndex %d\n", in->slot, in->rootSequenceIndex);
}
start_meas(in->rx_prach);
const uint16_t *prach_root_sequence_map =
in->prach_sequence_length == 0 ? prach_root_sequence_map_0_3 : prach_root_sequence_map_abc;
// PDP is oversampled, e.g. 1024 sample instead of 839
// Adapt the NCS (zero-correlation zones) with oversampling factor e.g. 1024/839
int NCS2 = N_ZC == 839 ? (NCS << 10) / 839 : (NCS << 8) / 139;
if (NCS2 == 0)
NCS2 = N_ZC;
int preamble_offset = 0, preamble_offset_old = 99;
int16_t preamble_shift = 0;
const int dft_sz = N_ZC == 839 ? 1024 : 256;
int32_t prach_ifft[dft_sz] __attribute__((aligned(32)));
for (int preamble_index = 0; preamble_index < 64; preamble_index++) {
if (LOG_DEBUGFLAG(DEBUG_PRACH)) {
int en = dB_fixed(signal_energy((int32_t *)in->rxsigF[occasion][0], N_ZC == 839 ? 840 : 140));
if (en > 60)
LOG_D(PHY, "frame %d, slot %d : Trying preamble %d \n", in->frame, in->slot, preamble_index);
}
if (in->restricted_set == 0) {
// This is the relative offset in the root sequence table (5.7.2-4 from 36.211) for the given preamble index
preamble_offset = ((NCS==0)? preamble_index : (preamble_index/(N_ZC/NCS)));
if (preamble_offset != preamble_offset_old) {
preamble_offset_old = preamble_offset;
new_dft = true;
// This is the \nu corresponding to the preamble index
preamble_shift = 0;
} else {
preamble_shift -= NCS;
if (preamble_shift < 0)
preamble_shift += N_ZC;
}
} else { // This is the high-speed case
new_dft = false;
uint16_t nr_du[NR_PRACH_SEQ_LEN_L - 1];
nr_fill_du(N_ZC, prach_root_sequence_map, nr_du);
// set preamble_offset to initial rootSequenceIndex and look if we need more root sequences for this
// preamble index and find the corresponding cyclic shift
// Check if all shifts for that root have been processed
int n_shift_ra = 0, n_shift_ra_bar, d_start = 0;
if (preamble_index0 == numshift) {
bool not_found = true;
new_dft = true;
preamble_index0 -= numshift;
while (not_found) {
// current root depending on rootSequenceIndex
int index = (in->rootSequenceIndex + preamble_offset) % N_ZC;
int u = nr_du[prach_root_sequence_map[index]];
uint16_t n_group_ra = 0;
if (u < (N_ZC / 3) && u >= NCS) {
n_shift_ra = u / NCS;
d_start = (u << 1) + (n_shift_ra * NCS);
n_group_ra = N_ZC / d_start;
n_shift_ra_bar = max(0, (N_ZC - (u << 1) - (n_group_ra * d_start)) / N_ZC);
} else if (u >= (N_ZC / 3) && u <= ((N_ZC - NCS) >> 1)) {
n_shift_ra = (N_ZC - (u << 1)) / NCS;
d_start = N_ZC - (u << 1) + (n_shift_ra * NCS);
n_group_ra = u / d_start;
n_shift_ra_bar = min(n_shift_ra, max(0, (u - (n_group_ra * d_start)) / NCS));
} else {
n_shift_ra = 0;
n_shift_ra_bar = 0;
}
// This is the number of cyclic shifts for the current root u
numshift = (n_shift_ra * n_group_ra) + n_shift_ra_bar;
// skip to next root and recompute parameters if numshift==0
numshift > 0 ? not_found = false : preamble_offset++;
}
}
if (n_shift_ra>0)
preamble_shift = -(d_start * (preamble_index0 / n_shift_ra)
+ (preamble_index0 % n_shift_ra) * NCS); // minus because the channel is h(t -\tau + Cv)
else
preamble_shift = 0;
if (preamble_shift < 0)
preamble_shift+=N_ZC;
preamble_index0++;
if (preamble_index == 0)
first_nonzero_root_idx = preamble_offset;
}
// Compute DFT of RX signal (conjugate in->rxsigF[occasion], results in conjugate output) for each new rootSequenceIndex
if (LOG_DEBUGFLAG(DEBUG_PRACH)) {
int en = dB_fixed(signal_energy((int32_t *)in->rxsigF[occasion][0], 840));
if (en>60)
LOG_D(PHY,
"frame %d, slot %d : preamble index %d, NCS %d, N_ZC/NCS %d: offset %d, preamble shift %d , en %d)\n",
in->frame,
in->slot,
preamble_index,
NCS,
N_ZC / NCS,
preamble_offset,
preamble_shift,
en);
}
LOG_D(NR_PHY_RACH,
"PRACH RX preamble_index %d, preamble_offset %d, preamb shift %d new dft %d\n",
preamble_index,
preamble_offset,
preamble_shift,
new_dft);
if (new_dft) {
new_dft = false;
c16_t *Xu = in->Xu[preamble_offset - first_nonzero_root_idx];
LOG_D(PHY,"PRACH RX new dft preamble_offset-first_nonzero_root_idx %d\n",preamble_offset-first_nonzero_root_idx);
memset(prach_ifft, 0, sizeof(prach_ifft));
if (LOG_DUMPFLAG(DEBUG_PRACH)) {
LOG_M("prach_rxF0.m", "prach_rxF0", in->rxsigF[occasion][0], N_ZC, 1, 1);
LOG_M("prach_rxF1.m", "prach_rxF1", in->rxsigF[occasion][1], 6144, 1, 1);
}
c16_t prachF[dft_sz] __attribute__((aligned(32)));
for (int aa = 0; aa < nb_rx; aa++) {
// Do componentwise product with Xu* on each antenna
for (int offset = 0; offset < N_ZC; offset++) {
prachF[offset] = c16MulConjShift(Xu[offset], in->rxsigF[occasion][aa][offset], 15);
}
memset(prachF + N_ZC, 0, sizeof(*prachF) * (dft_sz - N_ZC));
// Now do IFFT of size 1024 (N_ZC=839) or 256 (N_ZC=139)
c16_t prach_ifft_tmp[dft_sz] __attribute__((aligned(32)));
idft(get_idft(dft_sz), (int16_t *)prachF, (int16_t *)prach_ifft_tmp, 1);
// compute energy and accumulate over receive antennas
for (int i = 0; i < dft_sz; i++)
prach_ifft[i] += squaredMod(prach_ifft_tmp[i]);
if (LOG_DUMPFLAG(DEBUG_PRACH)) {
if (aa == 0)
LOG_M("prach_rxF_comp0.m","prach_rxF_comp0", prachF, 1024, 1, 1);
if (aa == 1)
LOG_M("prach_rxF_comp1.m","prach_rxF_comp1", prachF, 1024, 1, 1);
}
} // antennas_rx
// Normalization of energy over ifft and receive antennas
if (N_ZC == 839) {
log2_ifft_size = 10;
for (int i = 0; i < 1024; i++)
prach_ifft[i] = (prach_ifft[i]>>log2_ifft_size)/nb_rx;
} else {
log2_ifft_size = 8;
for (int i = 0; i < 256; i++)
prach_ifft[i] = (prach_ifft[i]>>log2_ifft_size)/nb_rx;
}
} // new dft
// check energy in nth time shift, for
int preamble_shift2 = preamble_shift == 0 ? 0 : (preamble_shift << log2_ifft_size) / N_ZC;
for (int i = 0; i < NCS2; i++) {
int lev = prach_ifft[preamble_shift2 + i];
int levdB = dB_fixed_times10(lev);
if (levdB > out.max_preamble_energy || (levdB == out.max_preamble_energy && out.max_preamble_delay > i)) {
LOG_D(NR_PHY_RACH, "preamble_index %d, delay %d en %d dB > %d dB\n", preamble_index, i, levdB, out.max_preamble_energy);
out.max_preamble_energy = levdB;
out.max_preamble_delay = i; // Note: This has to be normalized to the 30.72 Ms/s sampling rate
out.max_preamble = preamble_index;
}
}
} // preamble_index
// The conversion from *max_preamble_delay from TA value is done here.
// It is normalized to the 30.72 Ms/s, considering the numerology, N_RB and the sampling rate
// See table 6.3.3.1 -1 and -2 in 38211.
// Format 0, 1, 2: 24576 samples @ 30.72 Ms/s, 98304 samples @ 122.88 Ms/s
// By solving:
// max_preamble_delay * ( (24576*(fs/30.72M)) / 1024 ) / fs = TA * 16 * 64 / 2^mu * Tc
// Format 3: 6144 samples @ 30.72 Ms/s, 24576 samples @ 122.88 Ms/s
// By solving:
// max_preamble_delay * ( (6144*(fs/30.72M)) / 1024 ) / fs = TA * 16 * 64 / 2^mu * Tc
// Format >3: 2048/2^mu samples @ 30.72 Ms/s, 2048/2^mu * 4 samples @ 122.88 Ms/s
// By solving:
// max_preamble_delay * ( (2048/2^mu*(fs/30.72M)) / 256 ) / fs = TA * 16 * 64 / 2^mu * Tc
int mu = in->numerology_index;
if (in->prach_sequence_length == 0) {
if (prach_fmt == 0 || prach_fmt == 1 || prach_fmt == 2)
out.max_preamble_delay *= 3 * (1 << mu) / 2;
else if (prach_fmt == 3)
out.max_preamble_delay *= 3 * (1 << mu) / 8;
} else
out.max_preamble_delay /= 2;
stop_meas(in->rx_prach);
return out;
}
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