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C

/**
*
* \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 <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <stdint.h>
#include "srslte/fec/tc_interl.h"
#include "srslte/fec/turbocoder.h"
#define TURBO_SRSLTE_TCOD_RATE 3
uint32_t mcd(uint32_t x, uint32_t y);
/************************************************
*
* UMTS TURBO CODE INTERLEAVER
*
************************************************/
#define MAX_ROWS 20
#define MAX_COLS 256
const unsigned short table_p[52] = { 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43,
47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127,
131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199,
211, 223, 227, 229, 233, 239, 241, 251, 257 };
const uint8_t table_v[52] = { 3, 2, 2, 3, 2, 5, 2, 3, 2, 6, 3, 5, 2, 2, 2,
2, 7, 5, 3, 2, 3, 5, 2, 5, 2, 6, 3, 3, 2, 3, 2, 2, 6, 5, 2, 5, 2, 2, 2, 19,
5, 2, 3, 2, 3, 2, 6, 3, 7, 7, 6, 3 };
int srslte_tc_interl_init(srslte_tc_interl_t *h, uint32_t max_long_cb) {
int ret = -1;
h->forward = malloc(sizeof(uint32_t) * max_long_cb);
if (!h->forward) {
perror("malloc");
goto clean_exit;
}
h->reverse = malloc(sizeof(uint32_t) * max_long_cb);
if (!h->reverse) {
perror("malloc");
goto clean_exit;
}
h->max_long_cb = max_long_cb;
ret = 0;
clean_exit: if (ret == -1) {
srslte_tc_interl_free(h);
}
return ret;
}
void srslte_tc_interl_free(srslte_tc_interl_t *h) {
if (h->forward) {
free(h->forward);
}
if (h->reverse) {
free(h->reverse);
}
bzero(h, sizeof(srslte_tc_interl_t));
}
int srslte_tc_interl_UMTS_gen(srslte_tc_interl_t *h, uint32_t long_cb) {
uint32_t i, j;
uint32_t res, prim, aux;
uint32_t kp, k;
uint16_t *per, *desper;
uint8_t v;
uint16_t p;
uint16_t s[MAX_COLS], q[MAX_ROWS], r[MAX_ROWS], T[MAX_ROWS];
uint16_t U[MAX_COLS * MAX_ROWS];
uint32_t M_Rows, M_Cols, M_long;
M_long = long_cb;
if (long_cb > h->max_long_cb) {
fprintf(stderr, "Interleaver initiated for max_long_cb=%d\n",
h->max_long_cb);
return -1;
}
/* Find R*/
if ((40 <= M_long) && (M_long <= 159))
M_Rows = 5;
else if (((160 <= M_long) && (M_long <= 200))
|| ((481 <= M_long) && (M_long <= 530)))
M_Rows = 10;
else
M_Rows = 20;
/* Find p i v*/
if ((481 <= M_long) && (M_long <= 530)) {
p = 53;
v = 2;
M_Cols = p;
} else {
i = 0;
do {
p = table_p[i];
v = table_v[i];
i++;
} while (M_long > (M_Rows * (p + 1)));
}
/* Find C*/
if ((M_long) <= (M_Rows) * ((p) - 1))
M_Cols = (p) - 1;
else if (((M_Rows) * (p - 1) < M_long) && (M_long <= (M_Rows) * (p)))
M_Cols = p;
else if ((M_Rows) * (p) < M_long)
M_Cols = (p) + 1;
q[0] = 1;
prim = 6;
for (i = 1; i < M_Rows; i++) {
do {
prim++;
res = mcd(prim, p - 1);
} while (res != 1);
q[i] = prim;
}
s[0] = 1;
for (i = 1; i < p - 1; i++) {
s[i] = (v * s[i - 1]) % p;
}
if (M_long <= 159 && M_long >= 40) {
T[0] = 4;
T[1] = 3;
T[2] = 2;
T[3] = 1;
T[4] = 0;
} else if ((M_long <= 200 && M_long >= 160)
|| (M_long <= 530 && M_long >= 481)) {
T[0] = 9;
T[1] = 8;
T[2] = 7;
T[3] = 6;
T[4] = 5;
T[5] = 4;
T[6] = 3;
T[7] = 2;
T[8] = 1;
T[9] = 0;
} else if ((M_long <= 2480 && M_long >= 2281)
|| (M_long <= 3210 && M_long >= 3161)) {
T[0] = 19;
T[1] = 9;
T[2] = 14;
T[3] = 4;
T[4] = 0;
T[5] = 2;
T[6] = 5;
T[7] = 7;
T[8] = 12;
T[9] = 18;
T[10] = 16;
T[11] = 13;
T[12] = 17;
T[13] = 15;
T[14] = 3;
T[15] = 1;
T[16] = 6;
T[17] = 11;
T[18] = 8;
T[19] = 10;
} else {
T[0] = 19;
T[1] = 9;
T[2] = 14;
T[3] = 4;
T[4] = 0;
T[5] = 2;
T[6] = 5;
T[7] = 7;
T[8] = 12;
T[9] = 18;
T[10] = 10;
T[11] = 8;
T[12] = 13;
T[13] = 17;
T[14] = 3;
T[15] = 1;
T[16] = 16;
T[17] = 6;
T[18] = 15;
T[19] = 11;
}
for (i = 0; i < M_Rows; i++) {
r[T[i]] = q[i];
}
for (i = 0; i < M_Rows; i++) {
for (j = 0; j < p - 1; j++) {
U[i * M_Cols + j] = s[(j * r[i]) % (p - 1)];
if (M_Cols == (p - 1))
U[i * M_Cols + j] -= 1;
}
}
if (M_Cols == p) {
for (i = 0; i < M_Rows; i++)
U[i * M_Cols + p - 1] = 0;
} else if (M_Cols == p + 1) {
for (i = 0; i < M_Rows; i++) {
U[i * M_Cols + p - 1] = 0;
U[i * M_Cols + p] = p;
}
if (M_long == M_Cols * M_Rows) {
aux = U[(M_Rows - 1) * M_Cols + p];
U[(M_Rows - 1) * M_Cols + p] = U[(M_Rows - 1) * M_Cols + 0];
U[(M_Rows - 1) * M_Cols + 0] = aux;
}
}
per = h->forward;
desper = h->reverse;
k = 0;
for (j = 0; j < M_Cols; j++) {
for (i = 0; i < M_Rows; i++) {
kp = T[i] * M_Cols + U[i * M_Cols + j];
if (kp < M_long) {
desper[kp] = k;
per[k] = kp;
k++;
}
}
}
return 0;
}
uint32_t mcd(uint32_t x, uint32_t y) {
uint32_t r = 1;
while (r) {
r = x % y;
x = y;
y = r;
}
return x;
}