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srsRAN_4G/srslte/lib/phch/pucch.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 <complex.h>
#include "srslte/ch_estimation/refsignal_ul.h"
#include "srslte/phch/pucch.h"
#include "srslte/common/sequence.h"
#include "srslte/common/phy_common.h"
#include "srslte/scrambling/scrambling.h"
#include "srslte/utils/debug.h"
#include "srslte/utils/vector.h"
#define MAX_PUSCH_RE(cp) (2 * SRSLTE_CP_NSYMB(cp) * 12)
uint32_t pucch_symbol_format1_cpnorm[4] = {0, 1, 5, 6};
uint32_t pucch_symbol_format1_cpext[4] = {0, 1, 4, 5};
uint32_t pucch_symbol_format2_cpnorm[5] = {0, 2, 3, 4, 6};
uint32_t pucch_symbol_format2_cpext[5] = {0, 1, 2, 4, 5};
float w_n_oc[2][3][4] = {
// Table 5.4.1-2 Orthogonal sequences w for N_sf=4 (complex argument)
{{0, 0, 0, 0},
{0,M_PI, 0, M_PI},
{0,M_PI, M_PI, 0}},
// Table 5.4.1-3 Orthogonal sequences w for N_sf=3
{{0, 0, 0, 0},
{0,2*M_PI/3, 4*M_PI/3,0},
{0,4*M_PI/3,2*M_PI/3,0}},
};
/* Verify PUCCH configuration as given in Section 5.4 36.211 */
bool srslte_pucch_cfg_isvalid(srslte_pucch_cfg_t *cfg, uint32_t nof_prb) {
if (cfg->delta_pucch_shift > 0 && cfg->delta_pucch_shift < 4 &&
cfg->N_cs < 8 && (cfg->N_cs%cfg->delta_pucch_shift) == 0 &&
cfg->n_rb_2 < nof_prb) {
return true;
} else {
return false;
}
}
// Verifies n_2_pucch as defined in 5.4
bool srslte_pucch_n2_isvalid(srslte_pucch_cfg_t *cfg, uint32_t n_pucch_2) {
if (n_pucch_2 < cfg->n_rb_2*SRSLTE_NRE+(uint32_t) ceilf((float) cfg->N_cs/8)*(SRSLTE_NRE-cfg->N_cs-2)) {
return true;
} else {
return false;
}
}
void srslte_pucch_cfg_default(srslte_pucch_cfg_t *cfg) {
cfg->delta_pucch_shift = 1;
}
uint32_t get_N_sf(srslte_pucch_format_t format, uint32_t slot_idx, bool shortened) {
switch (format) {
case SRSLTE_PUCCH_FORMAT_1:
case SRSLTE_PUCCH_FORMAT_1A:
case SRSLTE_PUCCH_FORMAT_1B:
if (!slot_idx) {
return 4;
} else {
return shortened?3:4;
}
case SRSLTE_PUCCH_FORMAT_2:
case SRSLTE_PUCCH_FORMAT_2A:
case SRSLTE_PUCCH_FORMAT_2B:
return 5;
}
return 0;
}
uint32_t srslte_pucch_nof_symbols(srslte_pucch_cfg_t *cfg, srslte_pucch_format_t format, bool shortened) {
uint32_t len=0;
for (uint32_t ns=0;ns<2;ns++) {
len += SRSLTE_NRE*get_N_sf(format, ns, shortened);
}
return len;
}
// Number of bits per subframe (M_bit) Table 5.4-1 36.211
uint32_t srslte_pucch_nbits_format(srslte_pucch_format_t format) {
switch(format) {
case SRSLTE_PUCCH_FORMAT_1:
return 0;
case SRSLTE_PUCCH_FORMAT_1A:
return 1;
case SRSLTE_PUCCH_FORMAT_1B:
return 2;
case SRSLTE_PUCCH_FORMAT_2:
return 20;
case SRSLTE_PUCCH_FORMAT_2A:
return 21;
case SRSLTE_PUCCH_FORMAT_2B:
return 22;
}
return 0;
}
uint32_t get_pucch_symbol(uint32_t m, srslte_pucch_format_t format, srslte_cp_t cp) {
switch (format) {
case SRSLTE_PUCCH_FORMAT_1:
case SRSLTE_PUCCH_FORMAT_1A:
case SRSLTE_PUCCH_FORMAT_1B:
if (m < 5) {
if (SRSLTE_CP_ISNORM(cp)) {
return pucch_symbol_format1_cpnorm[m];
} else {
return pucch_symbol_format1_cpext[m];
}
}
break;
case SRSLTE_PUCCH_FORMAT_2:
case SRSLTE_PUCCH_FORMAT_2A:
case SRSLTE_PUCCH_FORMAT_2B:
if (m < 6) {
if (SRSLTE_CP_ISNORM(cp)) {
return pucch_symbol_format2_cpnorm[m];
} else {
return pucch_symbol_format2_cpext[m];
}
}
break;
}
return 0;
}
// Compute m according to Section 5.4.3 of 36.211
uint32_t srslte_pucch_m(srslte_pucch_cfg_t *cfg, srslte_pucch_format_t format, uint32_t n_pucch, srslte_cp_t cp) {
uint32_t m=0;
switch (format) {
case SRSLTE_PUCCH_FORMAT_1:
case SRSLTE_PUCCH_FORMAT_1A:
case SRSLTE_PUCCH_FORMAT_1B:
m = cfg->n_rb_2;
uint32_t c=SRSLTE_CP_ISNORM(cp)?3:2;
if (n_pucch >= c*cfg->N_cs/cfg->delta_pucch_shift) {
m = (n_pucch-c*cfg->N_cs/cfg->delta_pucch_shift)/(c*SRSLTE_NRE/cfg->delta_pucch_shift)
+cfg->n_rb_2+(uint32_t)ceilf((float) cfg->N_cs/8);
}
break;
case SRSLTE_PUCCH_FORMAT_2:
case SRSLTE_PUCCH_FORMAT_2A:
case SRSLTE_PUCCH_FORMAT_2B:
m = n_pucch/SRSLTE_NRE;
break;
}
return m;
}
/* Generates n_cs_cell according to Sec 5.4 of 36.211 */
int srslte_pucch_n_cs_cell(srslte_cell_t cell, uint32_t n_cs_cell[SRSLTE_NSLOTS_X_FRAME][SRSLTE_CP_NORM_NSYMB])
{
srslte_sequence_t seq;
bzero(&seq, sizeof(srslte_sequence_t));
srslte_sequence_LTE_pr(&seq, 8*SRSLTE_CP_NSYMB(cell.cp)*SRSLTE_NSLOTS_X_FRAME, cell.id);
for (uint32_t ns=0;ns<SRSLTE_NSLOTS_X_FRAME;ns++) {
for (uint32_t l=0;l<SRSLTE_CP_NSYMB(cell.cp);l++) {
n_cs_cell[ns][l] = 0;
for (uint32_t i=0;i<8;i++) {
n_cs_cell[ns][l] += seq.c[8*SRSLTE_CP_NSYMB(cell.cp)*ns+8*l+i]<<i;
}
}
}
srslte_sequence_free(&seq);
return SRSLTE_SUCCESS;
}
/* Calculates alpha for format 1/a/b according to 5.5.2.2.2 (is_dmrs=true) or 5.4.1 (is_dmrs=false) of 36.211 */
float srslte_pucch_alpha_format1(uint32_t n_cs_cell[SRSLTE_NSLOTS_X_FRAME][SRSLTE_CP_NORM_NSYMB],
srslte_pucch_cfg_t *cfg,
uint32_t n_pucch,
srslte_cp_t cp, bool is_dmrs,
uint32_t ns, uint32_t l,
uint32_t *n_oc_ptr, uint32_t *n_prime_ns)
{
uint32_t c = SRSLTE_CP_ISNORM(cp)?3:2;
uint32_t N_prime = (n_pucch < c*cfg->N_cs/cfg->delta_pucch_shift)?cfg->N_cs:SRSLTE_NRE;
uint32_t n_prime = n_pucch;
if (n_pucch >= c*cfg->N_cs/cfg->delta_pucch_shift) {
n_prime = (n_pucch-c*cfg->N_cs/cfg->delta_pucch_shift)%(c*SRSLTE_NRE/cfg->delta_pucch_shift);
}
if (ns%2) {
if (n_pucch >= c*cfg->N_cs/cfg->delta_pucch_shift) {
n_prime = (c*(n_prime+1))%(c*SRSLTE_NRE/cfg->delta_pucch_shift+1)-1;
} else {
uint32_t d=SRSLTE_CP_ISNORM(cp)?2:0;
uint32_t h=(n_prime+d)%(c*N_prime/cfg->delta_pucch_shift);
n_prime = (h/c)+(h%c)*N_prime/cfg->delta_pucch_shift;
}
}
if (n_prime_ns) {
*n_prime_ns = n_prime;
}
uint32_t n_oc_div = (!is_dmrs && SRSLTE_CP_ISEXT(cp))?2:1;
uint32_t n_oc = n_prime*cfg->delta_pucch_shift/N_prime;
if (!is_dmrs && SRSLTE_CP_ISEXT(cp)) {
n_oc *= 2;
}
if (n_oc_ptr) {
*n_oc_ptr = n_oc;
}
uint32_t n_cs = 0;
if (SRSLTE_CP_ISNORM(cp)) {
n_cs = (n_cs_cell[ns][l]+(n_prime*cfg->delta_pucch_shift+(n_oc%cfg->delta_pucch_shift))%N_prime)%SRSLTE_NRE;
} else {
n_cs = (n_cs_cell[ns][l]+(n_prime*cfg->delta_pucch_shift+n_oc/n_oc_div)%N_prime)%SRSLTE_NRE;
}
return 2 * M_PI * (n_cs) / SRSLTE_NRE;
}
/* Calculates alpha for format 2/a/b according to 5.4.2 of 36.211 */
float srslte_pucch_alpha_format2(uint32_t n_cs_cell[SRSLTE_NSLOTS_X_FRAME][SRSLTE_CP_NORM_NSYMB],
srslte_pucch_cfg_t *cfg,
uint32_t n_pucch,
uint32_t ns, uint32_t l)
{
uint32_t n_prime = n_pucch%SRSLTE_NRE;
if (n_pucch >= SRSLTE_NRE*cfg->n_rb_2) {
n_prime = (n_pucch + cfg->N_cs + 1)%SRSLTE_NRE;
}
if (ns%2) {
n_prime = (SRSLTE_NRE*(n_prime+1))%(SRSLTE_NRE+1)-1;
if (n_pucch >= SRSLTE_NRE*cfg->n_rb_2) {
int x = (SRSLTE_NRE-2-(int) n_pucch)%SRSLTE_NRE;
if (x >= 0) {
n_prime = (uint32_t) x;
} else {
n_prime = SRSLTE_NRE+x;
}
}
}
uint32_t n_cs = (n_cs_cell[ns][l]+n_prime)%SRSLTE_NRE;
float alpha = 2 * M_PI * (n_cs) / SRSLTE_NRE;
DEBUG("n_pucch: %d, ns: %d, l: %d, n_prime: %d, n_cs: %d, alpha=%f\n", n_pucch, ns, l, n_prime, n_cs, alpha);
return alpha;
}
/* Map PUCCH symbols to physical resources according to 5.4.3 in 36.211 */
static int pucch_put(srslte_pucch_t *q, srslte_pucch_format_t format, uint32_t n_pucch, cf_t *output) {
int ret = SRSLTE_ERROR_INVALID_INPUTS;
if (q && output) {
ret = SRSLTE_ERROR;
uint32_t nsymbols = SRSLTE_CP_ISNORM(q->cell.cp)?SRSLTE_CP_NORM_NSYMB:SRSLTE_CP_EXT_NSYMB;
// Determine m
uint32_t m = srslte_pucch_m(&q->pucch_cfg, format, n_pucch, q->cell.cp);
uint32_t N_sf_0 = get_N_sf(format, 0, q->shortened);
for (uint32_t ns=0;ns<2;ns++) {
uint32_t N_sf = get_N_sf(format, ns%2, q->shortened);
// Determine n_prb
uint32_t n_prb = m/2;
if ((m+ns)%2) {
n_prb = q->cell.nof_prb-1-m/2;
}
if (n_prb < q->cell.nof_prb) {
for (uint32_t i=0;i<N_sf;i++) {
uint32_t l = get_pucch_symbol(i, format, q->cell.cp);
memcpy(&output[SRSLTE_RE_IDX(q->cell.nof_prb, l+ns*nsymbols, n_prb*SRSLTE_NRE)],
&q->z[i*SRSLTE_NRE+ns*N_sf_0*SRSLTE_NRE],
SRSLTE_NRE*sizeof(cf_t));
}
} else {
return SRSLTE_ERROR;
}
}
ret = SRSLTE_SUCCESS;
}
return ret;
}
/** Initializes the PDCCH transmitter and receiver */
int srslte_pucch_init(srslte_pucch_t *q, srslte_cell_t cell) {
int ret = SRSLTE_ERROR_INVALID_INPUTS;
if (q != NULL && srslte_cell_isvalid(&cell)) {
ret = SRSLTE_ERROR;
bzero(q, sizeof(srslte_pucch_t));
q->cell = cell;
q->rnti_is_set = false;
srslte_pucch_cfg_default(&q->pucch_cfg);
if (srslte_modem_table_lte(&q->mod, SRSLTE_MOD_QPSK)) {
return SRSLTE_ERROR;
}
// Precompute group hopping values u.
if (srslte_group_hopping_f_gh(q->f_gh, q->cell.id)) {
return SRSLTE_ERROR;
}
if (srslte_pucch_n_cs_cell(q->cell, q->n_cs_cell)) {
return SRSLTE_ERROR;
}
ret = SRSLTE_SUCCESS;
}
return ret;
}
void srslte_pucch_free(srslte_pucch_t *q) {
if (q->rnti_is_set) {
for (uint32_t sf_idx=0;sf_idx<SRSLTE_NSUBFRAMES_X_FRAME;sf_idx++) {
srslte_sequence_free(&q->seq_f2[sf_idx]);
}
}
srslte_modem_table_free(&q->mod);
bzero(q, sizeof(srslte_pucch_t));
}
int srslte_pucch_set_crnti(srslte_pucch_t *q, uint16_t c_rnti) {
for (uint32_t sf_idx=0;sf_idx<SRSLTE_NSUBFRAMES_X_FRAME;sf_idx++) {
// Precompute scrambling sequence for pucch format 2
if (srslte_sequence_pucch(&q->seq_f2[sf_idx], c_rnti, 2*sf_idx, q->cell.id)) {
fprintf(stderr, "Error computing PUCCH Format 2 scrambling sequence\n");
return SRSLTE_ERROR;
}
}
q->rnti_is_set = true;
return SRSLTE_SUCCESS;
}
bool srslte_pucch_set_cfg(srslte_pucch_t *q, srslte_pucch_cfg_t *cfg, bool group_hopping_en)
{
q->group_hopping_en = group_hopping_en;
if (cfg) {
if (srslte_pucch_cfg_isvalid(cfg, q->cell.nof_prb)) {
memcpy(&q->pucch_cfg, cfg, sizeof(srslte_pucch_cfg_t));
return true;
} else {
return false;
}
} else {
return false;
}
}
static cf_t uci_encode_format1() {
return 1.0;
}
static cf_t uci_encode_format1a(uint8_t bit) {
return bit?-1.0:1.0;
}
static cf_t uci_encode_format1b(uint8_t bits[2]) {
if (bits[0] == 0) {
if (bits[1] == 0) {
return 1;
} else {
return -I;
}
} else {
if (bits[1] == 0) {
return I;
} else {
return -1.0;
}
}
}
/* Modulates bit 20 and 21 for Formats 2a and 2b as in Table 5.4.2-1 in 36.211 */
int srslte_pucch_format2ab_mod_bits(srslte_pucch_format_t format, uint8_t bits[2], cf_t *d_10) {
if (d_10) {
if (format == SRSLTE_PUCCH_FORMAT_2A) {
*d_10 = bits[0]?-1.0:1.0;
return SRSLTE_SUCCESS;
} else if (format == SRSLTE_PUCCH_FORMAT_2B) {
if (bits[0] == 0) {
if (bits[1] == 0) {
*d_10 = 1.0;
} else {
*d_10 = -I;
}
} else {
if (bits[1] == 0) {
*d_10 = I;
} else {
*d_10 = -1.0;
}
}
return SRSLTE_SUCCESS;
} else {
return SRSLTE_ERROR;
}
} else {
return SRSLTE_ERROR;
}
}
/* Encode PUCCH bits according to Table 5.4.1-1 in Section 5.4.1 of 36.211 */
static int uci_mod_bits(srslte_pucch_t *q, srslte_pucch_format_t format, uint8_t bits[SRSLTE_PUCCH_MAX_BITS], uint32_t sf_idx)
{
uint8_t tmp[2];
switch(format) {
case SRSLTE_PUCCH_FORMAT_1:
q->d[0] = uci_encode_format1();
break;
case SRSLTE_PUCCH_FORMAT_1A:
q->d[0] = uci_encode_format1a(bits[0]);
break;
case SRSLTE_PUCCH_FORMAT_1B:
tmp[0] = bits[0];
tmp[1] = bits[1];
q->d[0] = uci_encode_format1b(tmp);
break;
case SRSLTE_PUCCH_FORMAT_2:
case SRSLTE_PUCCH_FORMAT_2A:
case SRSLTE_PUCCH_FORMAT_2B:
memcpy(q->bits_scram, bits, SRSLTE_PUCCH_MAX_BITS*sizeof(uint8_t));
srslte_scrambling_b(&q->seq_f2[sf_idx], q->bits_scram);
srslte_mod_modulate(&q->mod, q->bits_scram, q->d, SRSLTE_PUCCH_MAX_BITS);
break;
default:
fprintf(stderr, "PUCCH format 2 not supported\n");
return SRSLTE_ERROR;
}
return SRSLTE_SUCCESS;
}
// Declare this here, since we can not include refsignal_ul.h
void srslte_refsignal_r_uv_arg_1prb(float *arg, uint32_t u);
/* Encode, modulate and resource mapping of PUCCH bits according to Section 5.4.1 of 36.211 */
int srslte_pucch_encode(srslte_pucch_t* q, srslte_pucch_format_t format,
uint32_t n_pucch, uint32_t sf_idx, uint8_t bits[SRSLTE_PUCCH_MAX_BITS], cf_t *sf_symbols)
{
int ret = SRSLTE_ERROR_INVALID_INPUTS;
if (q != NULL &&
sf_symbols != NULL)
{
ret = SRSLTE_ERROR;
// Shortened PUCCH happen in every cell-specific SRS subframes for Format 1/1a/1b
if (q->pucch_cfg.srs_configured && format < SRSLTE_PUCCH_FORMAT_2) {
q->shortened = false;
// If CQI is not transmitted, PUCCH will be normal unless ACK/NACK and SRS simultaneous transmission is enabled
if (q->pucch_cfg.srs_simul_ack) {
// If simultaneous ACK and SRS is enabled, PUCCH is shortened in cell-specific SRS subframes
if (srslte_refsignal_srs_send_cs(q->pucch_cfg.srs_cs_subf_cfg, sf_idx) == 1) {
q->shortened = true;
}
}
}
if (format >= SRSLTE_PUCCH_FORMAT_2 && !q->rnti_is_set) {
fprintf(stderr, "Error encoding PUCCH: C-RNTI must be set before encoding PUCCH Format 2/2a/2b\n");
return SRSLTE_ERROR;
}
if (uci_mod_bits(q, format, bits, sf_idx)) {
fprintf(stderr, "Error encoding PUCCH bits\n");
return SRSLTE_ERROR;
}
uint32_t N_sf_0 = get_N_sf(format, 0, q->shortened);
for (uint32_t ns=2*sf_idx;ns<2*(sf_idx+1);ns++) {
uint32_t N_sf = get_N_sf(format, ns%2, q->shortened);
DEBUG("ns=%d, N_sf=%d\n", ns, N_sf);
// Get group hopping number u
uint32_t f_gh=0;
if (q->group_hopping_en) {
f_gh = q->f_gh[ns];
}
uint32_t u = (f_gh + (q->cell.id%30))%30;
srslte_refsignal_r_uv_arg_1prb(q->tmp_arg, u);
uint32_t N_sf_widx = N_sf==3?1:0;
for (uint32_t m=0;m<N_sf;m++) {
uint32_t l = get_pucch_symbol(m, format, q->cell.cp);
float alpha=0;
if (format >= SRSLTE_PUCCH_FORMAT_2) {
alpha = srslte_pucch_alpha_format2(q->n_cs_cell, &q->pucch_cfg, n_pucch, ns, l);
for (uint32_t n=0;n<SRSLTE_PUCCH_N_SEQ;n++) {
q->z[(ns%2)*N_sf*SRSLTE_PUCCH_N_SEQ+m*SRSLTE_PUCCH_N_SEQ+n] = q->d[(ns%2)*N_sf+m]*cexpf(I*(q->tmp_arg[n]+alpha*n));
}
} else {
uint32_t n_prime_ns=0;
uint32_t n_oc=0;
alpha = srslte_pucch_alpha_format1(q->n_cs_cell, &q->pucch_cfg, n_pucch, q->cell.cp, true, ns, l, &n_oc, &n_prime_ns);
float S_ns = 0;
if (n_prime_ns%2) {
S_ns = M_PI/2;
}
DEBUG("PUCCH d_0: %.1f+%.1fi, alpha: %.1f, n_oc: %d, n_prime_ns: %d, n_rb_2=%d\n",
__real__ q->d[0], __imag__ q->d[0], alpha, n_oc, n_prime_ns, q->pucch_cfg.n_rb_2);
for (uint32_t n=0;n<SRSLTE_PUCCH_N_SEQ;n++) {
q->z[(ns%2)*N_sf_0*SRSLTE_PUCCH_N_SEQ+m*SRSLTE_PUCCH_N_SEQ+n] =
q->d[0]*cexpf(I*(w_n_oc[N_sf_widx][n_oc%3][m]+q->tmp_arg[n]+alpha*n+S_ns));
}
}
}
}
if (pucch_put(q, format, n_pucch, sf_symbols)) {
fprintf(stderr, "Error putting PUCCH symbols\n");
return SRSLTE_ERROR;
}
ret = SRSLTE_SUCCESS;
}
return ret;
}
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