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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 <strings.h>
#include <math.h>
#include "srslte/fec/turbodecoder_gen.h"
#include "srslte/fec/cbsegm.h"
#include "srslte/utils/debug.h"
const uint32_t tc_cb_sizes[SRSLTE_NOF_TC_CB_SIZES] = { 40, 48, 56, 64, 72, 80, 88, 96, 104, 112, 120,
128, 136, 144, 152, 160, 168, 176, 184, 192, 200, 208, 216, 224, 232,
240, 248, 256, 264, 272, 280, 288, 296, 304, 312, 320, 328, 336, 344,
352, 360, 368, 376, 384, 392, 400, 408, 416, 424, 432, 440, 448, 456,
464, 472, 480, 488, 496, 504, 512, 528, 544, 560, 576, 592, 608, 624,
640, 656, 672, 688, 704, 720, 736, 752, 768, 784, 800, 816, 832, 848,
864, 880, 896, 912, 928, 944, 960, 976, 992, 1008, 1024, 1056, 1088,
1120, 1152, 1184, 1216, 1248, 1280, 1312, 1344, 1376, 1408, 1440, 1472,
1504, 1536, 1568, 1600, 1632, 1664, 1696, 1728, 1760, 1792, 1824, 1856,
1888, 1920, 1952, 1984, 2016, 2048, 2112, 2176, 2240, 2304, 2368, 2432,
2496, 2560, 2624, 2688, 2752, 2816, 2880, 2944, 3008, 3072, 3136, 3200,
3264, 3328, 3392, 3456, 3520, 3584, 3648, 3712, 3776, 3840, 3904, 3968,
4032, 4096, 4160, 4224, 4288, 4352, 4416, 4480, 4544, 4608, 4672, 4736,
4800, 4864, 4928, 4992, 5056, 5120, 5184, 5248, 5312, 5376, 5440, 5504,
5568, 5632, 5696, 5760, 5824, 5888, 5952, 6016, 6080, 6144 };
/* Calculate Codeblock Segmentation as in Section 5.1.2 of 36.212 */
int srslte_cbsegm(srslte_cbsegm_t *s, uint32_t tbs) {
uint32_t Bp, B, idx1;
int ret;
if (tbs == 0) {
bzero(s, sizeof(srslte_cbsegm_t));
ret = SRSLTE_SUCCESS;
} else {
B = tbs + 24;
s->tbs = tbs;
/* Calculate CB sizes */
if (B <= SRSLTE_TCOD_MAX_LEN_CB) {
s->C = 1;
Bp = B;
} else {
s->C = (uint32_t) ceilf((float) B / (SRSLTE_TCOD_MAX_LEN_CB - 24));
Bp = B + 24 * s->C;
}
ret = srslte_cbsegm_cbindex((Bp-1) / s->C + 1);
if (ret != SRSLTE_ERROR) {
idx1 = (uint32_t) ret;
ret = srslte_cbsegm_cbsize(idx1);
if (ret != SRSLTE_ERROR) {
s->K1 = (uint32_t) ret;
s->K1_idx = idx1;
if (idx1 > 0) {
ret = srslte_cbsegm_cbsize(idx1 - 1);
}
if (ret != SRSLTE_ERROR) {
if (s->C == 1) {
s->K2 = 0;
s->K2_idx = 0;
s->C2 = 0;
s->C1 = 1;
} else {
s->K2 = (uint32_t) ret;
s->K2_idx = idx1-1;
s->C2 = (s->C * s->K1 - Bp) / (s->K1 - s->K2);
s->C1 = s->C - s->C2;
}
s->F = s->C1 * s->K1 + s->C2 * s->K2 - Bp;
INFO("CB Segmentation: TBS: %d, C=%d, C+=%d K+=%d, C-=%d, K-=%d, F=%d, Bp=%d\n",
tbs, s->C, s->C1, s->K1, s->C2, s->K2, s->F, Bp);
ret = SRSLTE_SUCCESS;
}
}
}
}
return ret;
}
/*
* Finds index of minimum K>=long_cb in Table 5.1.3-3 of 36.212
*/
int srslte_cbsegm_cbindex(uint32_t long_cb) {
int j = 0;
while (j < SRSLTE_NOF_TC_CB_SIZES && tc_cb_sizes[j] < long_cb) {
j++;
}
if (j == SRSLTE_NOF_TC_CB_SIZES) {
return SRSLTE_ERROR;
} else {
return j;
}
}
/*
* Returns Turbo coder interleaver size for Table 5.1.3-3 (36.212) index
*/
int srslte_cbsegm_cbsize(uint32_t index) {
if (index < SRSLTE_NOF_TC_CB_SIZES) {
return (int) tc_cb_sizes[index];
} else {
return SRSLTE_ERROR;
}
}
bool srslte_cbsegm_cbsize_isvalid(uint32_t size) {
for (int i=0;i<SRSLTE_NOF_TC_CB_SIZES;i++) {
if (tc_cb_sizes[i] == size) {
return true;
}
}
return false;
}