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openairinterface5g/openair1/PHY/NR_TRANSPORT/nr_prach.c
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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(PHY_VARS_gNB *gNB)
{
AssertFatal(gNB != NULL, "gNB is null\n");
for (int i = 0; i < NUMBER_OF_NR_PRACH_MAX; i++){
gNB->prach_vars.list[i].frame = -1;
gNB->prach_vars.list[i].slot = -1;
gNB->prach_vars.list[i].num_slots = -1;
}
}
void free_nr_prach_entry(PHY_VARS_gNB *gNB, int prach_id)
{
gNB->prach_vars.list[prach_id].frame = -1;
gNB->prach_vars.list[prach_id].slot = -1;
gNB->prach_vars.list[prach_id].num_slots = -1;
free_and_zero(gNB->prach_vars.list[prach_id].beam_nb);
}
int16_t find_nr_prach(PHY_VARS_gNB *gNB,int frame, int slot, find_type_t type) {
AssertFatal(gNB!=NULL,"gNB is null\n");
for (uint16_t i=0; i<NUMBER_OF_NR_PRACH_MAX; i++) {
gNB_PRACH_list_t *p = gNB->prach_vars.list + i;
LOG_D(PHY, "searching for PRACH in %d.%d prach_index %d=> %d.%d\n", frame, slot, i, p->frame, p->slot);
if ((type == SEARCH_EXIST_OR_FREE) && (p->frame == -1) && (p->slot == -1)) {
return i;
} else if ((type == SEARCH_EXIST) && (p->frame == frame) && (p->slot + p->num_slots - 1 == slot)) {
return i;
}
}
return -1;
}
int nr_fill_prach(PHY_VARS_gNB *gNB, int SFN, int Slot, nfapi_nr_prach_pdu_t *prach_pdu)
{
int prach_id = find_nr_prach(gNB, SFN, Slot, SEARCH_EXIST_OR_FREE);
AssertFatal(((prach_id >= 0) && (prach_id < NUMBER_OF_NR_PRACH_MAX)), "illegal or no prach_id found!!! prach_id %d\n", prach_id);
gNB_PRACH_list_t *prach = &gNB->prach_vars.list[prach_id];
prach->frame = SFN;
prach->slot = Slot;
const int format = prach_pdu->prach_format;
prach->num_slots = (format < 4) ? get_long_prach_dur(format, gNB->frame_parms.numerology_index) : 1;
if (gNB->common_vars.beam_id) {
int n_symb = get_nr_prach_duration(prach_pdu->prach_format);
prach->beam_nb = calloc(prach_pdu->beamforming.dig_bf_interface, sizeof(*prach->beam_nb));
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->beam_nb[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);
}
}
LOG_D(NR_PHY,"Copying prach pdu %d bytes to index %d\n", (int)sizeof(*prach_pdu), prach_id);
memcpy(&prach->pdu, prach_pdu, sizeof(*prach_pdu));
return prach_id;
}
void init_prach_ru_list(RU_t *ru)
{
AssertFatal(ru != NULL, "ru is null\n");
for (int i = 0; i < NUMBER_OF_NR_RU_PRACH_MAX; i++) {
ru->prach_list[i].frame = -1;
ru->prach_list[i].slot = -1;
ru->prach_list[i].num_slots = -1;
}
pthread_mutex_init(&ru->prach_list_mutex, NULL);
}
int16_t find_nr_prach_ru(RU_t *ru,int frame,int slot, find_type_t type)
{
AssertFatal(ru != NULL, "ru is null\n");
pthread_mutex_lock(&ru->prach_list_mutex);
for (int i = 0; i < NUMBER_OF_NR_RU_PRACH_MAX; i++) {
RU_PRACH_list_t *p = ru->prach_list + i;
LOG_D(PHY, "searching for PRACH in %d.%d : prach_index %d=> %d.%d\n", frame, slot, i, p->frame, p->slot);
if ((type == SEARCH_EXIST_OR_FREE) && (p->frame == -1) && (p->slot == -1)) {
pthread_mutex_unlock(&ru->prach_list_mutex);
return i;
} else if ((type == SEARCH_EXIST) && (p->frame == frame) && (p->slot + p->num_slots - 1 == slot)) {
pthread_mutex_unlock(&ru->prach_list_mutex);
return i;
}
}
pthread_mutex_unlock(&ru->prach_list_mutex);
return -1;
}
void nr_fill_prach_ru(RU_t *ru, int SFN, int Slot, nfapi_nr_prach_pdu_t *prach_pdu, int *beam_id)
{
int prach_id = find_nr_prach_ru(ru, SFN, Slot, SEARCH_EXIST_OR_FREE);
AssertFatal((prach_id >= 0) && (prach_id < NUMBER_OF_NR_PRACH_MAX),
"illegal or no prach_id found!!! prach_id %d\n",
prach_id);
pthread_mutex_lock(&ru->prach_list_mutex);
ru->prach_list[prach_id].frame = SFN;
ru->prach_list[prach_id].slot = Slot;
const int fmt = prach_pdu->prach_format;
ru->prach_list[prach_id].num_slots = (fmt < 4) ? get_long_prach_dur(fmt, ru->nr_frame_parms->numerology_index) : 1;
ru->prach_list[prach_id].fmt = fmt;
ru->prach_list[prach_id].numRA = prach_pdu->num_ra;
ru->prach_list[prach_id].beam = beam_id;
ru->prach_list[prach_id].prachStartSymbol = prach_pdu->prach_start_symbol;
ru->prach_list[prach_id].num_prach_ocas = prach_pdu->num_prach_ocas;
pthread_mutex_unlock(&ru->prach_list_mutex);
}
void free_nr_ru_prach_entry(RU_t *ru, int prach_id)
{
pthread_mutex_lock(&ru->prach_list_mutex);
ru->prach_list[prach_id].frame = -1;
ru->prach_list[prach_id].slot = -1;
pthread_mutex_unlock(&ru->prach_list_mutex);
}
void rx_nr_prach_ru(RU_t *ru,
int prachFormat,
int numRA,
int beam,
int prachStartSymbol,
int prachStartSlot,
int prachOccasion,
int frame,
int slot)
{
AssertFatal(ru != NULL,"ru is null\n");
NR_DL_FRAME_PARMS *fp = ru->nr_frame_parms;
int slot2 = slot;
int16_t *prach[ru->nb_rx];
int prach_sequence_length = ru->config.prach_config.prach_sequence_length.value;
int msg1_frequencystart = ru->config.prach_config.num_prach_fd_occasions_list[numRA].k1.value;
const uint8_t prach_mu = ru->config.prach_config.prach_sub_c_spacing.value;
int sample_offset_slot;
if (prachStartSymbol == 0) {
sample_offset_slot = 0;
} else if (fp->slots_per_subframe == 1) {
if (prachStartSymbol <= 7)
sample_offset_slot = (fp->ofdm_symbol_size + fp->nb_prefix_samples) * (prachStartSymbol - 1) + (fp->ofdm_symbol_size + fp->nb_prefix_samples0);
else
sample_offset_slot = (fp->ofdm_symbol_size + fp->nb_prefix_samples) * (prachStartSymbol - 2) + (fp->ofdm_symbol_size + fp->nb_prefix_samples0) * 2;
} else {
if (!(slot%(fp->slots_per_subframe/2)))
sample_offset_slot = (fp->ofdm_symbol_size + fp->nb_prefix_samples) * (prachStartSymbol - 1) + (fp->ofdm_symbol_size + fp->nb_prefix_samples0);
else
sample_offset_slot = (fp->ofdm_symbol_size + fp->nb_prefix_samples) * prachStartSymbol;
}
LOG_D(PHY,
"frame %d, slot %d: doing rx_nr_prach_ru for format %d, numRA %d, prachStartSymbol %d, prachOccasion %d\n",
frame,
slot,
prachFormat,
numRA,
prachStartSymbol,
prachOccasion);
int16_t **rxsigF = ru->prach_rxsigF[prachOccasion];
AssertFatal(ru->if_south == LOCAL_RF || ru->if_south == REMOTE_IF5,
"we shouldn't call this if if_south != LOCAL_RF or REMOTE_IF5\n");
for (int aa = 0; aa < ru->nb_rx; aa++) {
if (prach_sequence_length == 0)
slot2 = prachStartSlot;
int idx = aa + beam * ru->nb_rx;
prach[aa] = (int16_t*)&ru->common.rxdata[idx][fp->get_samples_slot_timestamp(slot2, fp, 0) + sample_offset_slot - ru->N_TA_offset];
}
int reps;
int Ncp;
int dftlen;
int mu = fp->numerology_index;
if (prach_sequence_length == 0) {
LOG_D(PHY,
"PRACH (ru %d) in %d.%d, format %d, msg1_frequencyStart %d\n",
ru->idx,
frame,
slot2,
prachFormat,
msg1_frequencystart);
switch (prachFormat) {
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", prachFormat);
break;
}
}
else {
LOG_D(PHY,
"PRACH (ru %d) in %d.%d, format %s, msg1_frequencyStart %d,startSymbol %d\n",
ru->idx,
frame,
slot,
prachfmt[prachFormat],
msg1_frequencystart,
prachStartSymbol);
switch (prachFormat) {
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",prachFormat);
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(fp->numerology_index == 0) {
if (prachStartSymbol == 0 || prachStartSymbol == 7)
Ncp += 16;
}
else {
if (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", ru->nb_rx, Ncp, dftlen);
}
const unsigned int K = get_prach_K(prach_sequence_length, prachFormat, fp->numerology_index, prach_mu);
const uint8_t kbar = get_PRACH_k_bar(prach_mu, fp->numerology_index);
int n_ra_prb = msg1_frequencystart;
int k = (12*n_ra_prb) - 6*fp->N_RB_UL;
int N_ZC = (prach_sequence_length==0)?839:139;
if (k<0) k+=(fp->ofdm_symbol_size);
k*=K;
k+=kbar;
for (int aa=0; aa<ru->nb_rx; aa++) {
AssertFatal(prach[aa]!=NULL,"prach[%d] is null\n",aa);
// do DFT
int16_t *prach2 = prach[aa] + (2*Ncp); // times 2 for complex samples
for (int i = 0; i < reps; i++)
dft(dftsize, prach2 + 2*dftlen*i, rxsigF[aa] + 2*dftlen*i, 1);
//LOG_M("ru_rxsigF_tmp.m","rxsFtmp", rxsigF[aa], dftlen*2*reps, 1, 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);
int16_t rxsigF_tmp[N_ZC<<1];
// if (k+N_ZC > dftlen) { // PRACH signal is split around DC
int16_t *rxsigF2=rxsigF[aa];
int k2=k<<1;
for (int j=0;j<N_ZC<<1;j++,k2++) {
if (k2==(dftlen<<1)) k2=0;
rxsigF_tmp[j] = rxsigF2[k2];
for (int i=1;i<reps;i++) rxsigF_tmp[j] += rxsigF2[k2+(i*dftlen<<1)];
}
memcpy((void*)rxsigF2,(void *)rxsigF_tmp,N_ZC<<2);
}
}
void rx_nr_prach(PHY_VARS_gNB *gNB,
nfapi_nr_prach_pdu_t *prach_pdu,
int prachOccasion,
int frame,
int slot,
uint16_t *max_preamble,
uint16_t *max_preamble_energy,
uint16_t *max_preamble_delay)
{
AssertFatal(gNB != NULL, "Can only be called from gNB\n");
nfapi_nr_prach_config_t *cfg = &gNB->gNB_config.prach_config;
NR_DL_FRAME_PARMS *fp;
uint16_t rootSequenceIndex;
int numrootSequenceIndex;
uint8_t restricted_set;
uint8_t n_ra_prb=0xFF;
int nb_rx;
int16_t **rxsigF = gNB->prach_vars.rxsigF;
uint8_t preamble_index;
uint16_t NCS=99,NCS2;
uint16_t preamble_offset=0,preamble_offset_old;
int16_t preamble_shift=0;
uint32_t preamble_shift2;
uint16_t preamble_index0=0,n_shift_ra=0,n_shift_ra_bar;
uint16_t d_start=0;
uint16_t numshift=0;
const uint16_t *prach_root_sequence_map;
uint8_t not_found;
uint16_t u;
int16_t *Xu=0;
uint16_t first_nonzero_root_idx=0;
uint8_t new_dft=0;
int32_t lev;
int16_t levdB;
int log2_ifft_size=10;
int16_t prach_ifft_tmp[2048*2] __attribute__((aligned(32)));
int32_t *prach_ifft=(int32_t*)NULL;
fp = &gNB->frame_parms;
nb_rx = gNB->gNB_config.carrier_config.num_rx_ant.value;
rootSequenceIndex = cfg->num_prach_fd_occasions_list[prach_pdu->num_ra].prach_root_sequence_index.value;
numrootSequenceIndex = cfg->num_prach_fd_occasions_list[prach_pdu->num_ra].num_root_sequences.value;
NCS = prach_pdu->num_cs;//cfg->num_prach_fd_occasions_list[0].prach_zero_corr_conf.value;
int prach_sequence_length = cfg->prach_sequence_length.value;
int msg1_frequencystart = cfg->num_prach_fd_occasions_list[prach_pdu->num_ra].k1.value;
// int num_unused_root_sequences = cfg->num_prach_fd_occasions_list[0].num_unused_root_sequences.value;
// cfg->num_prach_fd_occasions_list[0].unused_root_sequences_list
restricted_set = cfg->restricted_set_config.value;
uint8_t prach_fmt = prach_pdu->prach_format;
uint16_t N_ZC = (prach_sequence_length==0)?839:139;
LOG_D(PHY,"L1 PRACH RX: rooSequenceIndex %d, numRootSeqeuences %d, NCS %d, N_ZC %d, format %d \n",rootSequenceIndex,numrootSequenceIndex,NCS,N_ZC,prach_fmt);
prach_ifft = gNB->prach_vars.prach_ifft;
if (LOG_DEBUGFLAG(DEBUG_PRACH)) {
if ((frame&1023) < 20) LOG_D(PHY,"PRACH (gNB) : running rx_prach for slot %d, msg1_frequencystart %d, rootSequenceIndex %d\n", slot, msg1_frequencystart, rootSequenceIndex);
}
start_meas(&gNB->rx_prach);
prach_root_sequence_map = (cfg->prach_sequence_length.value==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
NCS2 = (N_ZC==839) ? ((NCS<<10)/839) : ((NCS<<8)/139);
if (NCS2==0) NCS2 = N_ZC;
preamble_offset_old = 99;
*max_preamble_energy = 0;
*max_preamble_delay = 0;
*max_preamble = 0;
int16_t prachF[2 * 1024];
for (preamble_index=0 ; preamble_index<64 ; preamble_index++) {
if (LOG_DEBUGFLAG(DEBUG_PRACH)) {
int en = dB_fixed(signal_energy((int32_t*)&rxsigF[0][0],(N_ZC==839) ? 840: 140));
if (en>60) LOG_D(PHY,"frame %d, slot %d : Trying preamble %d \n",frame,slot,preamble_index);
}
if (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 = 1;
// 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 = 0;
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
if (preamble_index0 == numshift) {
not_found = 1;
new_dft = 1;
preamble_index0 -= numshift;
//(preamble_offset==0 && numshift==0) ? (preamble_offset) : (preamble_offset++);
while (not_found == 1) {
// current root depending on rootSequenceIndex
int index = (rootSequenceIndex + preamble_offset) % N_ZC;
u = prach_root_sequence_map[index];
uint16_t n_group_ra = 0;
if ((nr_du[u] < (N_ZC / 3)) && (nr_du[u] >= NCS) ) {
n_shift_ra = nr_du[u] / NCS;
d_start = (nr_du[u] << 1) + (n_shift_ra * NCS);
n_group_ra = N_ZC / d_start;
n_shift_ra_bar = max(0, (N_ZC-(nr_du[u] << 1) - (n_group_ra * d_start)) / N_ZC);
} else if ((nr_du[u] >= (N_ZC / 3)) && (nr_du[u] <= ((N_ZC - NCS) >> 1))) {
n_shift_ra = (N_ZC - (nr_du[u] << 1)) / NCS;
d_start = N_ZC - (nr_du[u] << 1) + (n_shift_ra * NCS);
n_group_ra = nr_du[u] / d_start;
n_shift_ra_bar = min(n_shift_ra, max(0, (nr_du[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 = 0) : (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 input, results in conjugate output) for each new rootSequenceIndex
if (LOG_DEBUGFLAG(DEBUG_PRACH)) {
int en = dB_fixed(signal_energy((int32_t*)&rxsigF[0][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",
frame,
slot,
preamble_index,
NCS,
N_ZC / NCS,
preamble_offset,
preamble_shift,
en);
}
LOG_D(PHY,"PRACH RX preamble_index %d, preamble_offset %d\n",preamble_index,preamble_offset);
if (new_dft == 1) {
new_dft = 0;
Xu = (int16_t*)gNB->X_u[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,((N_ZC==839) ? 2048 : 256)*sizeof(int32_t));
memset(prachF, 0, sizeof(int16_t) * 2 * 1024);
if (LOG_DUMPFLAG(DEBUG_PRACH)) {
LOG_M("prach_rxF0.m","prach_rxF0",rxsigF[0],N_ZC,1,1);
LOG_M("prach_rxF1.m","prach_rxF1",rxsigF[1],6144,1,1);
}
for (int aa = 0; aa < nb_rx; aa++) {
// Do componentwise product with Xu* on each antenna
for (int offset = 0; offset < (N_ZC << 1); offset += 2) {
prachF[offset] = (int16_t)(((int32_t)Xu[offset]*rxsigF[aa][offset] + (int32_t)Xu[offset+1]*rxsigF[aa][offset+1])>>15);
prachF[offset+1] = (int16_t)(((int32_t)Xu[offset]*rxsigF[aa][offset+1] - (int32_t)Xu[offset+1]*rxsigF[aa][offset])>>15);
}
// Now do IFFT of size 1024 (N_ZC=839) or 256 (N_ZC=139)
if (N_ZC == 839) {
idft(IDFT_1024, prachF, prach_ifft_tmp, 1);
// compute energy and accumulate over receive antennas
for (int i = 0; i < 1024; i++)
prach_ifft[i] += (int32_t)prach_ifft_tmp[i<<1]*(int32_t)prach_ifft_tmp[i<<1] + (int32_t)prach_ifft_tmp[1+(i<<1)]*(int32_t)prach_ifft_tmp[1+(i<<1)];
} else {
idft(IDFT_256, prachF, prach_ifft_tmp, 1);
log2_ifft_size = 8;
// compute energy and accumulate over receive antennas and repetitions for BR
for (int i = 0; i < 256; i++)
prach_ifft[i] += (int32_t)prach_ifft_tmp[i<<1]*(int32_t)prach_ifft_tmp[(i<<1)] + (int32_t)prach_ifft_tmp[1+(i<<1)]*(int32_t)prach_ifft_tmp[1+(i<<1)];
}
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
preamble_shift2 = ((preamble_shift==0) ? 0 : ((preamble_shift<<log2_ifft_size)/N_ZC));
for (int i = 0; i < NCS2; i++) {
lev = (int32_t)prach_ifft[(preamble_shift2+i)];
levdB = dB_fixed_times10(lev);
if (levdB>*max_preamble_energy) {
LOG_D(PHY,"preamble_index %d, delay %d en %d dB > %d dB\n",preamble_index,i,levdB,*max_preamble_energy);
*max_preamble_energy = levdB;
*max_preamble_delay = i; // Note: This has to be normalized to the 30.72 Ms/s sampling rate
*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
uint16_t *TA = max_preamble_delay;
int mu = fp->numerology_index;
if (cfg->prach_sequence_length.value == 0) {
if (prach_fmt == 0 || prach_fmt == 1 || prach_fmt == 2)
*TA = *TA * 3 * (1 << mu) / 2;
else if (prach_fmt == 3)
*TA = *TA * 3 * (1 << mu) / 8;
}
else *TA = *TA/2;
if (LOG_DUMPFLAG(DEBUG_PRACH)) {
//int en = dB_fixed(signal_energy((int32_t*)&rxsigF[0][0],840));
// if (en>60) {
int k = (12 * n_ra_prb) - 6 * fp->N_RB_UL;
if (k < 0)
k += fp->ofdm_symbol_size;
k*=12;
k+=13;
k*=2;
LOG_M("rxsigF.m","prach_rxF", &rxsigF[0][0], 12288, 1, 1);
LOG_M("prach_rxF_comp0.m","prach_rxF_comp0", prachF, 1024, 1, 1);
LOG_M("Xu.m","xu", Xu, N_ZC, 1, 1);
LOG_M("prach_ifft0.m","prach_t0", prach_ifft, 1024, 1, 1);
// }
}
stop_meas(&gNB->rx_prach);
}
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