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srsLTE/srslte/lib/phch/pdsch.c

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/**
*
* \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 <stdint.h>
#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>
#include <stdbool.h>
#include <assert.h>
#include <math.h>
#include "prb_dl.h"
#include "srslte/phch/pdsch.h"
#include "srslte/phch/sch.h"
#include "srslte/common/phy_common.h"
#include "srslte/utils/bit.h"
#include "srslte/utils/debug.h"
#include "srslte/utils/vector.h"
#define MAX_PDSCH_RE(cp) (2 * SRSLTE_CP_NSYMB(cp) * 12)
const static srslte_mod_t modulations[4] =
{ SRSLTE_MOD_BPSK, SRSLTE_MOD_QPSK, SRSLTE_MOD_16QAM, SRSLTE_MOD_64QAM };
//#define DEBUG_IDX
#ifdef DEBUG_IDX
cf_t *offset_original=NULL;
extern int indices[100000];
extern int indices_ptr;
#endif
float srslte_pdsch_coderate(uint32_t tbs, uint32_t nof_re)
{
return (float) (tbs + 24)/(nof_re);
}
int srslte_pdsch_cp(srslte_pdsch_t *q, cf_t *input, cf_t *output, srslte_ra_dl_grant_t *grant, uint32_t lstart_grant, uint32_t nsubframe, bool put)
{
uint32_t s, n, l, lp, lstart, lend, nof_refs;
bool is_pbch, is_sss;
cf_t *in_ptr = input, *out_ptr = output;
uint32_t offset = 0;
#ifdef DEBUG_IDX
indices_ptr = 0;
if (put) {
offset_original = output;
} else {
offset_original = input;
}
#endif
if (q->cell.nof_ports == 1) {
nof_refs = 2;
} else {
nof_refs = 4;
}
for (s = 0; s < 2; s++) {
for (l = 0; l < SRSLTE_CP_NSYMB(q->cell.cp); l++) {
for (n = 0; n < q->cell.nof_prb; n++) {
// If this PRB is assigned
if (grant->prb_idx[s][n]) {
if (s == 0) {
lstart = lstart_grant;
} else {
lstart = 0;
}
lend = SRSLTE_CP_NSYMB(q->cell.cp);
is_pbch = is_sss = false;
// Skip PSS/SSS signals
if (s == 0 && (nsubframe == 0 || nsubframe == 5)) {
if (n >= q->cell.nof_prb / 2 - 3
&& n < q->cell.nof_prb / 2 + 3 + (q->cell.nof_prb%2)) {
lend = SRSLTE_CP_NSYMB(q->cell.cp) - 2;
is_sss = true;
}
}
// Skip PBCH
if (s == 1 && nsubframe == 0) {
if (n >= q->cell.nof_prb / 2 - 3
&& n < q->cell.nof_prb / 2 + 3 + (q->cell.nof_prb%2)) {
lstart = 4;
is_pbch = true;
}
}
lp = l + s * SRSLTE_CP_NSYMB(q->cell.cp);
if (put) {
out_ptr = &output[(lp * q->cell.nof_prb + n)
* SRSLTE_NRE];
} else {
in_ptr = &input[(lp * q->cell.nof_prb + n)
* SRSLTE_NRE];
}
// This is a symbol in a normal PRB with or without references
if (l >= lstart && l < lend) {
if (SRSLTE_SYMBOL_HAS_REF(l, q->cell.cp, q->cell.nof_ports)) {
if (nof_refs == 2) {
if (l == 0) {
offset = q->cell.id % 6;
} else {
offset = (q->cell.id + 3) % 6;
}
} else {
offset = q->cell.id % 3;
}
prb_cp_ref(&in_ptr, &out_ptr, offset, nof_refs, nof_refs, put);
} else {
prb_cp(&in_ptr, &out_ptr, 1);
}
}
// This is a symbol in a PRB with PBCH or Synch signals (SS).
// If the number or total PRB is odd, half of the the PBCH or SS will fall into the symbol
if ((q->cell.nof_prb % 2) && ((is_pbch && l < lstart) || (is_sss && l >= lend))) {
if (n == q->cell.nof_prb / 2 - 3) {
if (SRSLTE_SYMBOL_HAS_REF(l, q->cell.cp, q->cell.nof_ports)) {
prb_cp_ref(&in_ptr, &out_ptr, offset, nof_refs, nof_refs/2, put);
} else {
prb_cp_half(&in_ptr, &out_ptr, 1);
}
} else if (n == q->cell.nof_prb / 2 + 3) {
if (put) {
out_ptr += 6;
} else {
in_ptr += 6;
}
if (SRSLTE_SYMBOL_HAS_REF(l, q->cell.cp, q->cell.nof_ports)) {
prb_cp_ref(&in_ptr, &out_ptr, offset, nof_refs, nof_refs/2, put);
} else {
prb_cp_half(&in_ptr, &out_ptr, 1);
}
}
}
}
}
}
}
int r;
if (put) {
r = abs((int) (input - in_ptr));
} else {
r = abs((int) (output - out_ptr));
}
return r;
}
/**
* Puts PDSCH in slot number 1
*
* Returns the number of symbols written to sf_symbols
*
* 36.211 10.3 section 6.3.5
*/
int srslte_pdsch_put(srslte_pdsch_t *q, cf_t *symbols, cf_t *sf_symbols,
srslte_ra_dl_grant_t *grant, uint32_t lstart, uint32_t subframe)
{
return srslte_pdsch_cp(q, symbols, sf_symbols, grant, lstart, subframe, true);
}
/**
* Extracts PDSCH from slot number 1
*
* Returns the number of symbols written to PDSCH
*
* 36.211 10.3 section 6.3.5
*/
int srslte_pdsch_get(srslte_pdsch_t *q, cf_t *sf_symbols, cf_t *symbols,
srslte_ra_dl_grant_t *grant, uint32_t lstart, uint32_t subframe)
{
return srslte_pdsch_cp(q, sf_symbols, symbols, grant, lstart, subframe, false);
}
int srslte_pdsch_init(srslte_pdsch_t *q, srslte_cell_t cell)
{
return srslte_pdsch_init_multi(q, cell, 1);
}
/** Initializes the PDCCH transmitter and receiver */
int srslte_pdsch_init_multi(srslte_pdsch_t *q, srslte_cell_t cell, uint32_t nof_rx_antennas)
{
int ret = SRSLTE_ERROR_INVALID_INPUTS;
int i;
if (q != NULL &&
srslte_cell_isvalid(&cell) &&
nof_rx_antennas <= SRSLTE_MAX_PORTS)
{
bzero(q, sizeof(srslte_pdsch_t));
ret = SRSLTE_ERROR;
q->cell = cell;
q->max_re = q->cell.nof_prb * MAX_PDSCH_RE(q->cell.cp);
q->nof_rx_antennas = nof_rx_antennas;
INFO("Init PDSCH: %d ports %d PRBs, max_symbols: %d\n", q->cell.nof_ports,
q->cell.nof_prb, q->max_re);
for (i = 0; i < 4; i++) {
if (srslte_modem_table_lte(&q->mod[i], modulations[i])) {
goto clean;
}
srslte_modem_table_bytes(&q->mod[i]);
}
srslte_sch_init(&q->dl_sch);
// Allocate int16_t for reception (LLRs)
q->e = srslte_vec_malloc(sizeof(int16_t) * q->max_re * srslte_mod_bits_x_symbol(SRSLTE_MOD_64QAM));
if (!q->e) {
goto clean;
}
q->d = srslte_vec_malloc(sizeof(cf_t) * q->max_re);
if (!q->d) {
goto clean;
}
for (i = 0; i < q->cell.nof_ports; i++) {
q->x[i] = srslte_vec_malloc(sizeof(cf_t) * q->max_re);
if (!q->x[i]) {
goto clean;
}
for (int j=0;j<q->nof_rx_antennas;j++) {
q->ce[i][j] = srslte_vec_malloc(sizeof(cf_t) * q->max_re);
if (!q->ce[i][j]) {
goto clean;
}
}
}
for (int j=0;j<q->nof_rx_antennas;j++) {
q->symbols[j] = srslte_vec_malloc(sizeof(cf_t) * q->max_re);
if (!q->symbols[j]) {
goto clean;
}
}
q->users = calloc(sizeof(srslte_pdsch_user_t*), 1+SRSLTE_SIRNTI);
if (!q->users) {
perror("malloc");
goto clean;
}
ret = SRSLTE_SUCCESS;
}
clean:
if (ret == SRSLTE_ERROR) {
srslte_pdsch_free(q);
}
return ret;
}
void srslte_pdsch_free(srslte_pdsch_t *q) {
int i;
if (q->e) {
free(q->e);
}
if (q->d) {
free(q->d);
}
for (i = 0; i < q->cell.nof_ports; i++) {
if (q->x[i]) {
free(q->x[i]);
}
for (int j=0;j<q->nof_rx_antennas;j++) {
if (q->ce[i][j]) {
free(q->ce[i][j]);
}
}
}
for (int j=0;j<q->nof_rx_antennas;j++) {
if (q->symbols[j]) {
free(q->symbols[j]);
}
}
if (q->users) {
for (uint16_t u=0;u<SRSLTE_SIRNTI;u++) {
if (q->users[u]) {
srslte_pdsch_free_rnti(q, u);
}
}
free(q->users);
}
for (i = 0; i < 4; i++) {
srslte_modem_table_free(&q->mod[i]);
}
srslte_sch_free(&q->dl_sch);
bzero(q, sizeof(srslte_pdsch_t));
}
/* Configures the structure srslte_pdsch_cfg_t from the DL DCI allocation dci_msg.
* If dci_msg is NULL, the grant is assumed to be already stored in cfg->grant
*/
int srslte_pdsch_cfg(srslte_pdsch_cfg_t *cfg, srslte_cell_t cell, srslte_ra_dl_grant_t *grant, uint32_t cfi, uint32_t sf_idx, uint32_t rvidx)
{
if (cfg) {
if (grant) {
memcpy(&cfg->grant, grant, sizeof(srslte_ra_dl_grant_t));
}
if (srslte_cbsegm(&cfg->cb_segm, cfg->grant.mcs.tbs)) {
fprintf(stderr, "Error computing Codeblock segmentation for TBS=%d\n", cfg->grant.mcs.tbs);
return SRSLTE_ERROR;
}
srslte_ra_dl_grant_to_nbits(&cfg->grant, cfi, cell, sf_idx, &cfg->nbits);
cfg->sf_idx = sf_idx;
cfg->rv = rvidx;
return SRSLTE_SUCCESS;
} else {
return SRSLTE_ERROR_INVALID_INPUTS;
}
}
/* Precalculate the PDSCH scramble sequences for a given RNTI. This function takes a while
* to execute, so shall be called once the final C-RNTI has been allocated for the session.
*/
int srslte_pdsch_set_rnti(srslte_pdsch_t *q, uint16_t rnti) {
uint32_t i;
if (!q->users[rnti]) {
q->users[rnti] = calloc(1, sizeof(srslte_pdsch_user_t));
if (q->users[rnti]) {
for (i = 0; i < SRSLTE_NSUBFRAMES_X_FRAME; i++) {
if (srslte_sequence_pdsch(&q->users[rnti]->seq[i], rnti, 0, 2 * i, q->cell.id,
q->max_re * srslte_mod_bits_x_symbol(SRSLTE_MOD_64QAM))) {
return SRSLTE_ERROR;
}
}
}
}
return SRSLTE_SUCCESS;
}
void srslte_pdsch_free_rnti(srslte_pdsch_t* q, uint16_t rnti)
{
if (q->users[rnti]) {
for (int i = 0; i < SRSLTE_NSUBFRAMES_X_FRAME; i++) {
srslte_sequence_free(&q->users[rnti]->seq[i]);
}
free(q->users[rnti]);
q->users[rnti] = NULL;
}
}
int srslte_pdsch_decode(srslte_pdsch_t *q,
srslte_pdsch_cfg_t *cfg, srslte_softbuffer_rx_t *softbuffer,
cf_t *sf_symbols, cf_t *ce[SRSLTE_MAX_PORTS], float noise_estimate,
uint16_t rnti, uint8_t *data)
{
cf_t *_sf_symbols[SRSLTE_MAX_PORTS];
cf_t *_ce[SRSLTE_MAX_PORTS][SRSLTE_MAX_PORTS];
_sf_symbols[0] = sf_symbols;
for (int i=0;i<q->cell.nof_ports;i++) {
_ce[i][0] = ce[i];
}
return srslte_pdsch_decode_multi(q, cfg, softbuffer, _sf_symbols, _ce, noise_estimate, rnti, data);
}
/** Decodes the PDSCH from the received symbols
*/
int srslte_pdsch_decode_multi(srslte_pdsch_t *q,
srslte_pdsch_cfg_t *cfg, srslte_softbuffer_rx_t *softbuffer,
cf_t *sf_symbols[SRSLTE_MAX_PORTS], cf_t *ce[SRSLTE_MAX_PORTS][SRSLTE_MAX_PORTS], float noise_estimate,
uint16_t rnti, uint8_t *data)
{
/* Set pointers for layermapping & precoding */
uint32_t i, n;
cf_t *x[SRSLTE_MAX_LAYERS];
if (q != NULL &&
sf_symbols != NULL &&
data != NULL &&
cfg != NULL)
{
INFO("Decoding PDSCH SF: %d, RNTI: 0x%x, Mod %s, TBS: %d, NofSymbols: %d, NofBitsE: %d, rv_idx: %d, C_prb=%d\n",
cfg->sf_idx, rnti, srslte_mod_string(cfg->grant.mcs.mod), cfg->grant.mcs.tbs, cfg->nbits.nof_re,
cfg->nbits.nof_bits, cfg->rv, cfg->grant.nof_prb);
/* number of layers equals number of ports */
for (i = 0; i < q->cell.nof_ports; i++) {
x[i] = q->x[i];
}
memset(&x[q->cell.nof_ports], 0, sizeof(cf_t*) * (SRSLTE_MAX_LAYERS - q->cell.nof_ports));
for (int j=0;j<q->nof_rx_antennas;j++) {
/* extract symbols */
n = srslte_pdsch_get(q, sf_symbols[j], q->symbols[j], &cfg->grant, cfg->nbits.lstart, cfg->sf_idx);
if (n != cfg->nbits.nof_re) {
fprintf(stderr, "Error expecting %d symbols but got %d\n", cfg->nbits.nof_re, n);
return SRSLTE_ERROR;
}
/* extract channel estimates */
for (i = 0; i < q->cell.nof_ports; i++) {
n = srslte_pdsch_get(q, ce[i][j], q->ce[i][j], &cfg->grant, cfg->nbits.lstart, cfg->sf_idx);
if (n != cfg->nbits.nof_re) {
fprintf(stderr, "Error expecting %d symbols but got %d\n", cfg->nbits.nof_re, n);
return SRSLTE_ERROR;
}
}
}
/* TODO: only diversity is supported */
if (q->cell.nof_ports == 1) {
/* no need for layer demapping */
srslte_predecoding_single_multi(q->symbols, q->ce[0], q->d, q->nof_rx_antennas, cfg->nbits.nof_re, noise_estimate);
} else {
srslte_predecoding_diversity_multi(q->symbols, q->ce, x, q->nof_rx_antennas, q->cell.nof_ports, cfg->nbits.nof_re);
srslte_layerdemap_diversity(x, q->d, q->cell.nof_ports, cfg->nbits.nof_re / q->cell.nof_ports);
}
if (SRSLTE_VERBOSE_ISDEBUG()) {
DEBUG("SAVED FILE subframe.dat: received subframe symbols\n",0);
srslte_vec_save_file("subframe.dat", sf_symbols, SRSLTE_SF_LEN_RE(q->cell.nof_prb, q->cell.cp)*sizeof(cf_t));
DEBUG("SAVED FILE hest0.dat and hest1.dat: channel estimates for port 0 and port 1\n",0);
srslte_vec_save_file("hest0.dat", ce[0], SRSLTE_SF_LEN_RE(q->cell.nof_prb, q->cell.cp)*sizeof(cf_t));
if (q->cell.nof_ports > 1) {
srslte_vec_save_file("hest1.dat", ce[1], SRSLTE_SF_LEN_RE(q->cell.nof_prb, q->cell.cp)*sizeof(cf_t));
}
DEBUG("SAVED FILE pdsch_symbols.dat: symbols after equalization\n",0);
srslte_vec_save_file("pdsch_symbols.dat", q->d, cfg->nbits.nof_re*sizeof(cf_t));
}
/* demodulate symbols
* The MAX-log-MAP algorithm used in turbo decoding is unsensitive to SNR estimation,
* thus we don't need tot set it in the LLRs normalization
*/
srslte_demod_soft_demodulate_s(cfg->grant.mcs.mod, q->d, q->e, cfg->nbits.nof_re);
/* descramble */
if (!q->users[rnti]) {
srslte_sequence_t seq;
if (srslte_sequence_pdsch(&seq, rnti, 0, 2 * cfg->sf_idx, q->cell.id, cfg->nbits.nof_bits)) {
return SRSLTE_ERROR;
}
srslte_scrambling_s_offset(&seq, q->e, 0, cfg->nbits.nof_bits);
srslte_sequence_free(&seq);
} else {
srslte_scrambling_s_offset(&q->users[rnti]->seq[cfg->sf_idx], q->e, 0, cfg->nbits.nof_bits);
}
if (SRSLTE_VERBOSE_ISDEBUG()) {
DEBUG("SAVED FILE llr.dat: LLR estimates after demodulation and descrambling\n",0);
srslte_vec_save_file("llr.dat", q->e, cfg->nbits.nof_bits*sizeof(int16_t));
}
return srslte_dlsch_decode(&q->dl_sch, cfg, softbuffer, q->e, data);
} else {
return SRSLTE_ERROR_INVALID_INPUTS;
}
}
int srslte_pdsch_encode(srslte_pdsch_t *q,
srslte_pdsch_cfg_t *cfg, srslte_softbuffer_tx_t *softbuffer,
uint8_t *data, uint16_t rnti, cf_t *sf_symbols[SRSLTE_MAX_PORTS])
{
int i;
/* Set pointers for layermapping & precoding */
cf_t *x[SRSLTE_MAX_LAYERS];
int ret = SRSLTE_ERROR_INVALID_INPUTS;
if (q != NULL &&
cfg != NULL)
{
for (i=0;i<q->cell.nof_ports;i++) {
if (sf_symbols[i] == NULL) {
return SRSLTE_ERROR_INVALID_INPUTS;
}
}
if (cfg->grant.mcs.tbs == 0) {
return SRSLTE_ERROR_INVALID_INPUTS;
}
if (cfg->nbits.nof_re > q->max_re) {
fprintf(stderr,
"Error too many RE per subframe (%d). PDSCH configured for %d RE (%d PRB)\n",
cfg->nbits.nof_re, q->max_re, q->cell.nof_prb);
return SRSLTE_ERROR_INVALID_INPUTS;
}
INFO("Encoding PDSCH SF: %d, Mod %s, NofBits: %d, NofSymbols: %d, NofBitsE: %d, rv_idx: %d\n",
cfg->sf_idx, srslte_mod_string(cfg->grant.mcs.mod), cfg->grant.mcs.tbs,
cfg->nbits.nof_re, cfg->nbits.nof_bits, cfg->rv);
/* number of layers equals number of ports */
for (i = 0; i < q->cell.nof_ports; i++) {
x[i] = q->x[i];
}
memset(&x[q->cell.nof_ports], 0, sizeof(cf_t*) * (SRSLTE_MAX_LAYERS - q->cell.nof_ports));
if (srslte_dlsch_encode(&q->dl_sch, cfg, softbuffer, data, q->e)) {
fprintf(stderr, "Error encoding TB\n");
return SRSLTE_ERROR;
}
/* scramble */
if (!q->users[rnti]) {
srslte_sequence_t seq;
if (srslte_sequence_pdsch(&seq, rnti, 0, 2 * cfg->sf_idx, q->cell.id, cfg->nbits.nof_bits)) {
return SRSLTE_ERROR;
}
srslte_scrambling_bytes(&q->users[rnti]->seq[cfg->sf_idx], (uint8_t*) q->e, cfg->nbits.nof_bits);
srslte_sequence_free(&seq);
} else {
srslte_scrambling_bytes(&q->users[rnti]->seq[cfg->sf_idx], (uint8_t*) q->e, cfg->nbits.nof_bits);
}
srslte_mod_modulate_bytes(&q->mod[cfg->grant.mcs.mod], (uint8_t*) q->e, q->d, cfg->nbits.nof_bits);
/* TODO: only diversity supported */
if (q->cell.nof_ports > 1) {
srslte_layermap_diversity(q->d, x, q->cell.nof_ports, cfg->nbits.nof_re);
srslte_precoding_diversity(x, q->symbols, q->cell.nof_ports,
cfg->nbits.nof_re / q->cell.nof_ports);
} else {
memcpy(q->symbols[0], q->d, cfg->nbits.nof_re * sizeof(cf_t));
}
/* mapping to resource elements */
for (i = 0; i < q->cell.nof_ports; i++) {
srslte_pdsch_put(q, q->symbols[i], sf_symbols[i], &cfg->grant, cfg->nbits.lstart, cfg->sf_idx);
}
ret = SRSLTE_SUCCESS;
}
return ret;
}
float srslte_pdsch_average_noi(srslte_pdsch_t *q)
{
return q->dl_sch.average_nof_iterations;
}
uint32_t srslte_pdsch_last_noi(srslte_pdsch_t *q) {
return q->dl_sch.nof_iterations;
}
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