From 3262f820b5cfb4c76448f605c9804f3e5ca1023d Mon Sep 17 00:00:00 2001 From: Vadim Yanitskiy Date: Fri, 23 Sep 2016 01:48:59 +0700 Subject: libosmocoding: migrate transcoding routines from OsmoBTS There are some projects, such as GR-GSM and OsmocomBB, which would benefit from using one shared implementation of GSM 05.03 code. So, this commit introduces a new sub-library called libosmocoding, which (for now) provides GSM, GPRS and EDGE transcoding routines, migrated from OsmoBTS. The original GSM 05.03 code from OsmoBTS was relicensed under GPLv2-or-later with permission of copyright holders (Andreas Eversberg, Alexander Chemeris and Tom Tsou). The following data types are currently supported: - xCCH - PDTCH (CS 1-4 and MCS 1-9) - TCH/FR - TCH/HR - TCH/AFS - RCH/AHS - RACH - SCH Change-Id: I0c3256b87686d878e4e716d12393cad5924fdfa1 --- src/coding/Makefile.am | 27 + src/coding/gsm0503_coding.c | 2681 +++++++++++++++++++++++++++++++++++++ src/coding/gsm0503_interleaving.c | 573 ++++++++ src/coding/gsm0503_mapping.c | 291 ++++ src/coding/gsm0503_parity.c | 132 ++ src/coding/gsm0503_tables.c | 1732 ++++++++++++++++++++++++ src/coding/libosmocoding.map | 117 ++ src/gsm/libosmogsm.map | 2 + 8 files changed, 5555 insertions(+) create mode 100644 src/coding/Makefile.am create mode 100644 src/coding/gsm0503_coding.c create mode 100644 src/coding/gsm0503_interleaving.c create mode 100644 src/coding/gsm0503_mapping.c create mode 100644 src/coding/gsm0503_parity.c create mode 100644 src/coding/gsm0503_tables.c create mode 100644 src/coding/libosmocoding.map (limited to 'src') diff --git a/src/coding/Makefile.am b/src/coding/Makefile.am new file mode 100644 index 00000000..5a055c8d --- /dev/null +++ b/src/coding/Makefile.am @@ -0,0 +1,27 @@ +# This is _NOT_ the library release version, it's an API version. +# Please read Chapter 6 "Library interface versions" of the libtool +# documentation before making any modification +LIBVERSION = 0:0:0 + +AM_CPPFLAGS = -I$(top_srcdir)/include $(TALLOC_CFLAGS) +AM_CFLAGS = -Wall + +lib_LTLIBRARIES = libosmocoding.la + +libosmocoding_la_SOURCES = \ + gsm0503_interleaving.c \ + gsm0503_mapping.c \ + gsm0503_tables.c \ + gsm0503_parity.c \ + gsm0503_coding.c +libosmocoding_la_LDFLAGS = \ + -version-info \ + $(LIBVERSION) \ + -no-undefined \ + $(TALLOC_LIBS) +libosmocoding_la_LIBADD = \ + ../libosmocore.la \ + ../gsm/libosmogsm.la \ + ../codec/libosmocodec.la + +EXTRA_DIST = libosmocoding.map diff --git a/src/coding/gsm0503_coding.c b/src/coding/gsm0503_coding.c new file mode 100644 index 00000000..30ec387b --- /dev/null +++ b/src/coding/gsm0503_coding.c @@ -0,0 +1,2681 @@ +/* + * (C) 2013 by Andreas Eversberg + * (C) 2015 by Alexander Chemeris + * (C) 2016 by Tom Tsou + * + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +#include +#include + +#include +#include +#include + +#include +#include +#include +#include +#include + +/* + * EGPRS coding limits + */ + +/* Max header size with parity bits */ +#define EGPRS_HDR_UPP_MAX 54 + +/* Max encoded header size */ +#define EGPRS_HDR_C_MAX 162 + +/* Max punctured header size */ +#define EGPRS_HDR_HC_MAX 160 + +/* Max data block size with parity bits */ +#define EGPRS_DATA_U_MAX 612 + +/* Max encoded data block size */ +#define EGPRS_DATA_C_MAX 1836 + +/* Max single block punctured data size */ +#define EGPRS_DATA_DC_MAX 1248 + +/* Dual block punctured data size */ +#define EGPRS_DATA_C1 612 +#define EGPRS_DATA_C2 EGPRS_DATA_C1 + +/* TS 101318 Chapter 5.1: 260 bits + 4bit sig */ +#define GSM_FR_BYTES 33 +/* TS 101318 Chapter 5.2: 112 bits, no sig */ +#define GSM_HR_BYTES 14 +/* TS 101318 Chapter 5.3: 244 bits + 4bit sig */ +#define GSM_EFR_BYTES 31 + +union gprs_rlc_ul_hdr_egprs { + struct gprs_rlc_ul_header_egprs_1 type1; + struct gprs_rlc_ul_header_egprs_2 type2; + struct gprs_rlc_ul_header_egprs_3 type3; +}; + +union gprs_rlc_dl_hdr_egprs { + struct gprs_rlc_dl_header_egprs_1 type1; + struct gprs_rlc_dl_header_egprs_2 type2; + struct gprs_rlc_dl_header_egprs_3 type3; +}; + +struct gsm0503_mcs_code { + uint8_t mcs; + uint8_t usf_len; + + /* Header coding */ + uint8_t hdr_len; + uint8_t hdr_code_len; + uint8_t hdr_punc_len; + const struct osmo_conv_code *hdr_conv; + const uint8_t *hdr_punc; + + /* Data coding */ + uint16_t data_len; + uint16_t data_code_len; + uint16_t data_punc_len; + const struct osmo_conv_code *data_conv; + const uint8_t *data_punc[3]; +}; + +/* + * EGPRS UL coding parameters + */ +struct gsm0503_mcs_code gsm0503_mcs_ul_codes[EGPRS_NUM_MCS] = { + { + .mcs = EGPRS_MCS0, + }, + { + .mcs = EGPRS_MCS1, + .hdr_len = 31, + .hdr_code_len = 117, + .hdr_punc_len = 80, + .hdr_conv = &gsm0503_mcs1_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs1_ul_hdr, + + .data_len = 178, + .data_code_len = 588, + .data_punc_len = 372, + .data_conv = &gsm0503_mcs1, + .data_punc = { + gsm0503_puncture_mcs1_p1, + gsm0503_puncture_mcs1_p2, + NULL, + }, + }, + { + .mcs = EGPRS_MCS2, + .hdr_len = 31, + .hdr_code_len = 117, + .hdr_punc_len = 80, + .hdr_conv = &gsm0503_mcs1_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs1_ul_hdr, + + .data_len = 226, + .data_code_len = 732, + .data_punc_len = 372, + .data_conv = &gsm0503_mcs2, + .data_punc = { + gsm0503_puncture_mcs2_p1, + gsm0503_puncture_mcs2_p2, + NULL, + }, + }, + { + .mcs = EGPRS_MCS3, + .hdr_len = 31, + .hdr_code_len = 117, + .hdr_punc_len = 80, + .hdr_conv = &gsm0503_mcs1_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs1_ul_hdr, + + .data_len = 298, + .data_code_len = 948, + .data_punc_len = 372, + .data_conv = &gsm0503_mcs3, + .data_punc = { + gsm0503_puncture_mcs3_p1, + gsm0503_puncture_mcs3_p2, + gsm0503_puncture_mcs3_p3, + }, + }, + { + .mcs = EGPRS_MCS4, + .hdr_len = 31, + .hdr_code_len = 117, + .hdr_punc_len = 80, + .hdr_conv = &gsm0503_mcs1_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs1_ul_hdr, + + .data_len = 354, + .data_code_len = 1116, + .data_punc_len = 372, + .data_conv = &gsm0503_mcs4, + .data_punc = { + gsm0503_puncture_mcs4_p1, + gsm0503_puncture_mcs4_p2, + gsm0503_puncture_mcs4_p3, + }, + }, + { + .mcs = EGPRS_MCS5, + .hdr_len = 37, + .hdr_code_len = 135, + .hdr_punc_len = 136, + .hdr_conv = &gsm0503_mcs5_ul_hdr, + .hdr_punc = NULL, + + .data_len = 450, + .data_code_len = 1404, + .data_punc_len = 1248, + .data_conv = &gsm0503_mcs5, + .data_punc = { + gsm0503_puncture_mcs5_p1, + gsm0503_puncture_mcs5_p2, + NULL, + }, + }, + { + .mcs = EGPRS_MCS6, + .hdr_len = 37, + .hdr_code_len = 135, + .hdr_punc_len = 136, + .hdr_conv = &gsm0503_mcs5_ul_hdr, + .hdr_punc = NULL, + + .data_len = 594, + .data_code_len = 1836, + .data_punc_len = 1248, + .data_conv = &gsm0503_mcs6, + .data_punc = { + gsm0503_puncture_mcs6_p1, + gsm0503_puncture_mcs6_p2, + NULL, + }, + }, + { + .mcs = EGPRS_MCS7, + .hdr_len = 46, + .hdr_code_len = 162, + .hdr_punc_len = 160, + .hdr_conv = &gsm0503_mcs7_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs7_ul_hdr, + + .data_len = 900, + .data_code_len = 1404, + .data_punc_len = 612, + .data_conv = &gsm0503_mcs7, + .data_punc = { + gsm0503_puncture_mcs7_p1, + gsm0503_puncture_mcs7_p2, + gsm0503_puncture_mcs7_p3, + } + }, + { + .mcs = EGPRS_MCS8, + .hdr_len = 46, + .hdr_code_len = 162, + .hdr_punc_len = 160, + .hdr_conv = &gsm0503_mcs7_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs7_ul_hdr, + + .data_len = 1092, + .data_code_len = 1692, + .data_punc_len = 612, + .data_conv = &gsm0503_mcs8, + .data_punc = { + gsm0503_puncture_mcs8_p1, + gsm0503_puncture_mcs8_p2, + gsm0503_puncture_mcs8_p3, + } + }, + { + .mcs = EGPRS_MCS9, + .hdr_len = 46, + .hdr_code_len = 162, + .hdr_punc_len = 160, + .hdr_conv = &gsm0503_mcs7_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs7_ul_hdr, + + .data_len = 1188, + .data_code_len = 1836, + .data_punc_len = 612, + .data_conv = &gsm0503_mcs9, + .data_punc = { + gsm0503_puncture_mcs9_p1, + gsm0503_puncture_mcs9_p2, + gsm0503_puncture_mcs9_p3, + } + }, +}; + +/* + * EGPRS DL coding parameters + */ +struct gsm0503_mcs_code gsm0503_mcs_dl_codes[EGPRS_NUM_MCS] = { + { + .mcs = EGPRS_MCS0, + }, + { + .mcs = EGPRS_MCS1, + .usf_len = 3, + .hdr_len = 28, + .hdr_code_len = 108, + .hdr_punc_len = 68, + .hdr_conv = &gsm0503_mcs1_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs1_dl_hdr, + + .data_len = 178, + .data_code_len = 588, + .data_punc_len = 372, + .data_conv = &gsm0503_mcs1, + .data_punc = { + gsm0503_puncture_mcs1_p1, + gsm0503_puncture_mcs1_p2, + NULL, + }, + }, + { + .mcs = EGPRS_MCS2, + .usf_len = 3, + .hdr_len = 28, + .hdr_code_len = 108, + .hdr_punc_len = 68, + .hdr_conv = &gsm0503_mcs1_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs1_dl_hdr, + + .data_len = 226, + .data_code_len = 732, + .data_punc_len = 372, + .data_conv = &gsm0503_mcs2, + .data_punc = { + gsm0503_puncture_mcs2_p1, + gsm0503_puncture_mcs2_p2, + NULL, + }, + }, + { + .mcs = EGPRS_MCS3, + .usf_len = 3, + .hdr_len = 28, + .hdr_code_len = 108, + .hdr_punc_len = 68, + .hdr_conv = &gsm0503_mcs1_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs1_dl_hdr, + + .data_len = 298, + .data_code_len = 948, + .data_punc_len = 372, + .data_conv = &gsm0503_mcs3, + .data_punc = { + gsm0503_puncture_mcs3_p1, + gsm0503_puncture_mcs3_p2, + gsm0503_puncture_mcs3_p3, + }, + }, + { + .mcs = EGPRS_MCS4, + .usf_len = 3, + .hdr_len = 28, + .hdr_code_len = 108, + .hdr_punc_len = 68, + .hdr_conv = &gsm0503_mcs1_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs1_dl_hdr, + + .data_len = 354, + .data_code_len = 1116, + .data_punc_len = 372, + .data_conv = &gsm0503_mcs4, + .data_punc = { + gsm0503_puncture_mcs4_p1, + gsm0503_puncture_mcs4_p2, + gsm0503_puncture_mcs4_p3, + }, + }, + { + .mcs = EGPRS_MCS5, + .usf_len = 3, + .hdr_len = 25, + .hdr_code_len = 99, + .hdr_punc_len = 100, + .hdr_conv = &gsm0503_mcs5_dl_hdr, + .hdr_punc = NULL, + + .data_len = 450, + .data_code_len = 1404, + .data_punc_len = 1248, + .data_conv = &gsm0503_mcs5, + .data_punc = { + gsm0503_puncture_mcs5_p1, + gsm0503_puncture_mcs5_p2, + NULL, + }, + }, + { + .mcs = EGPRS_MCS6, + .usf_len = 3, + .hdr_len = 25, + .hdr_code_len = 99, + .hdr_punc_len = 100, + .hdr_conv = &gsm0503_mcs5_dl_hdr, + .hdr_punc = NULL, + + .data_len = 594, + .data_code_len = 1836, + .data_punc_len = 1248, + .data_conv = &gsm0503_mcs6, + .data_punc = { + gsm0503_puncture_mcs6_p1, + gsm0503_puncture_mcs6_p2, + NULL, + }, + }, + { + .mcs = EGPRS_MCS7, + .usf_len = 3, + .hdr_len = 37, + .hdr_code_len = 135, + .hdr_punc_len = 124, + .hdr_conv = &gsm0503_mcs7_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs7_dl_hdr, + + .data_len = 900, + .data_code_len = 1404, + .data_punc_len = 612, + .data_conv = &gsm0503_mcs7, + .data_punc = { + gsm0503_puncture_mcs7_p1, + gsm0503_puncture_mcs7_p2, + gsm0503_puncture_mcs7_p3, + } + }, + { + .mcs = EGPRS_MCS8, + .usf_len = 3, + .hdr_len = 37, + .hdr_code_len = 135, + .hdr_punc_len = 124, + .hdr_conv = &gsm0503_mcs7_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs7_dl_hdr, + + .data_len = 1092, + .data_code_len = 1692, + .data_punc_len = 612, + .data_conv = &gsm0503_mcs8, + .data_punc = { + gsm0503_puncture_mcs8_p1, + gsm0503_puncture_mcs8_p2, + gsm0503_puncture_mcs8_p3, + } + }, + { + .mcs = EGPRS_MCS9, + .usf_len = 3, + .hdr_len = 37, + .hdr_code_len = 135, + .hdr_punc_len = 124, + .hdr_conv = &gsm0503_mcs7_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs7_dl_hdr, + + .data_len = 1188, + .data_code_len = 1836, + .data_punc_len = 612, + .data_conv = &gsm0503_mcs9, + .data_punc = { + gsm0503_puncture_mcs9_p1, + gsm0503_puncture_mcs9_p2, + gsm0503_puncture_mcs9_p3, + } + }, +}; + +static int osmo_conv_decode_ber(const struct osmo_conv_code *code, + const sbit_t *input, ubit_t *output, + int *n_errors, int *n_bits_total) +{ + int res, i, coded_len; + ubit_t recoded[EGPRS_DATA_C_MAX]; + + res = osmo_conv_decode(code, input, output); + + if (n_bits_total || n_errors) { + coded_len = osmo_conv_encode(code, output, recoded); + OSMO_ASSERT(sizeof(recoded) / sizeof(recoded[0]) >= coded_len); + } + + /* Count bit errors */ + if (n_errors) { + *n_errors = 0; + for (i = 0; i < coded_len; i++) { + if (!((recoded[i] && input[i] < 0) || + (!recoded[i] && input[i] > 0)) ) + *n_errors += 1; + } + } + + if (n_bits_total) + *n_bits_total = coded_len; + + return res; +} + +static int _xcch_decode_cB(uint8_t *l2_data, sbit_t *cB, + int *n_errors, int *n_bits_total) +{ + ubit_t conv[224]; + int rv; + + osmo_conv_decode_ber(&gsm0503_xcch, cB, + conv, n_errors, n_bits_total); + + rv = osmo_crc64gen_check_bits(&gsm0503_fire_crc40, + conv, 184, conv + 184); + if (rv) + return -1; + + osmo_ubit2pbit_ext(l2_data, 0, conv, 0, 184, 1); + + return 0; +} + +static int _xcch_encode_cB(ubit_t *cB, uint8_t *l2_data) +{ + ubit_t conv[224]; + + osmo_pbit2ubit_ext(conv, 0, l2_data, 0, 184, 1); + + osmo_crc64gen_set_bits(&gsm0503_fire_crc40, conv, 184, conv + 184); + + osmo_conv_encode(&gsm0503_xcch, conv, cB); + + return 0; +} + +/* + * GSM xCCH block transcoding + */ +int gsm0503_xcch_decode(uint8_t *l2_data, sbit_t *bursts, + int *n_errors, int *n_bits_total) +{ + sbit_t iB[456], cB[456]; + int i; + + for (i = 0; i < 4; i++) + gsm0503_xcch_burst_unmap(&iB[i * 114], &bursts[i * 116], NULL, NULL); + + gsm0503_xcch_deinterleave(cB, iB); + + return _xcch_decode_cB(l2_data, cB, n_errors, n_bits_total); +} + +int gsm0503_xcch_encode(ubit_t *bursts, uint8_t *l2_data) +{ + ubit_t iB[456], cB[456], hl = 1, hn = 1; + int i; + + _xcch_encode_cB(cB, l2_data); + + gsm0503_xcch_interleave(cB, iB); + + for (i = 0; i < 4; i++) + gsm0503_xcch_burst_map(&iB[i * 114], &bursts[i * 116], &hl, &hn); + + return 0; +} + +/* + * EGPRS PDTCH UL block decoding + */ + +/* + * Type 3 - MCS-1,2,3,4 + * Unmapping and deinterleaving + */ +static int egprs_type3_unmap(const sbit_t *bursts, sbit_t *hc, sbit_t *dc) +{ + int i; + sbit_t iB[456], q[8]; + + for (i = 0; i < 4; i++) { + gsm0503_xcch_burst_unmap(&iB[i * 114], &bursts[i * 116], + q + i * 2, q + i * 2 + 1); + } + + gsm0503_mcs1_ul_deinterleave(hc, dc, iB); + + return 0; +} + +/* + * Type 2 - MCS-5,6 + * Unmapping and deinterleaving + */ +static int egprs_type2_unmap(const sbit_t *bursts, sbit_t *hc, sbit_t *dc) +{ + int i; + sbit_t burst[348]; + sbit_t hi[EGPRS_HDR_HC_MAX]; + sbit_t di[EGPRS_DATA_DC_MAX]; + + for (i = 0; i < 4; i++) { + memcpy(burst, &bursts[i * 348], 348); + + gsm0503_mcs5_burst_swap(burst); + gsm0503_mcs5_ul_burst_unmap(di, burst, hi, i); + } + + gsm0503_mcs5_ul_deinterleave(hc, dc, hi, di); + + return 0; +} + +/* + * Type 1 - MCS-7,8,9 + * Unmapping and deinterleaving - Note that MCS-7 interleaver is unique + */ +static int egprs_type1_unmap(const sbit_t *bursts, sbit_t *hc, + sbit_t *c1, sbit_t *c2, int msc) +{ + int i; + sbit_t burst[348]; + sbit_t hi[EGPRS_HDR_HC_MAX]; + sbit_t di[EGPRS_DATA_C1 * 2]; + + for (i = 0; i < 4; i++) { + memcpy(burst, &bursts[i * 348], 348); + + gsm0503_mcs5_burst_swap(burst); + gsm0503_mcs7_ul_burst_unmap(di, burst, hi, i); + } + + if (msc == EGPRS_MCS7) + gsm0503_mcs7_ul_deinterleave(hc, c1, c2, hi, di); + else + gsm0503_mcs8_ul_deinterleave(hc, c1, c2, hi, di); + + return 0; +} + +/* + * Decode EGPRS UL header section + * + * 1. Depuncture + * 2. Convolutional decoding + * 3. CRC check + */ +static int _egprs_decode_hdr(const sbit_t *hc, int mcs, + union gprs_rlc_ul_hdr_egprs *hdr) +{ + sbit_t C[EGPRS_HDR_C_MAX]; + ubit_t upp[EGPRS_HDR_UPP_MAX]; + int i, j, rc; + struct gsm0503_mcs_code *code; + + code = &gsm0503_mcs_ul_codes[mcs]; + + /* Skip depuncturing on MCS-5,6 header */ + if ((mcs == EGPRS_MCS5) || (mcs == EGPRS_MCS6)) { + memcpy(C, hc, code->hdr_code_len); + goto hdr_conv_decode; + } + + if (!code->hdr_punc) { + /* Invalid MCS-X header puncture matrix */ + return -1; + } + + i = code->hdr_code_len - 1; + j = code->hdr_punc_len - 1; + + for (; i >= 0; i--) { + if (!code->hdr_punc[i]) + C[i] = hc[j--]; + else + C[i] = 0; + } + +hdr_conv_decode: + osmo_conv_decode_ber(code->hdr_conv, C, upp, NULL, NULL); + rc = osmo_crc8gen_check_bits(&gsm0503_mcs_crc8_hdr, upp, + code->hdr_len, upp + code->hdr_len); + if (rc) + return -1; + + osmo_ubit2pbit_ext((pbit_t *) hdr, 0, upp, 0, code->hdr_len, 1); + + return 0; +} + +/* + * Blind MCS header decoding based on burst length and CRC validation. + * Ignore 'q' value coding identification. This approach provides + * the strongest chance of header recovery. + */ +static int egprs_decode_hdr(union gprs_rlc_ul_hdr_egprs *hdr, + const sbit_t *bursts, uint16_t nbits) +{ + int rc; + sbit_t hc[EGPRS_HDR_HC_MAX]; + + if (nbits == GSM0503_GPRS_BURSTS_NBITS) { + /* MCS-1,2,3,4 */ + egprs_type3_unmap(bursts, hc, NULL); + rc = _egprs_decode_hdr(hc, EGPRS_MCS1, hdr); + if (!rc) + return EGPRS_HDR_TYPE3; + } else if (nbits == GSM0503_EGPRS_BURSTS_NBITS) { + /* MCS-5,6 */ + egprs_type2_unmap(bursts, hc, NULL); + rc = _egprs_decode_hdr(hc, EGPRS_MCS5, hdr); + if (!rc) + return EGPRS_HDR_TYPE2; + + /* MCS-7,8,9 */ + egprs_type1_unmap(bursts, hc, NULL, NULL, EGPRS_MCS7); + rc = _egprs_decode_hdr(hc, EGPRS_MCS7, hdr); + if (!rc) + return EGPRS_HDR_TYPE1; + } + + return -1; +} + +/* + * Parse EGPRS UL header for coding and puncturing scheme (CPS) + * + * Type 1 - MCS-7,8,9 + * Type 2 - MCS-5,6 + * Type 3 - MCS-1,2,3,4 + */ +static int egprs_parse_ul_cps(struct egprs_cps *cps, + union gprs_rlc_ul_hdr_egprs *hdr, int type) +{ + uint8_t bits; + + switch (type) { + case EGPRS_HDR_TYPE1: + bits = hdr->type1.cps; + break; + case EGPRS_HDR_TYPE2: + bits = (hdr->type2.cps_lo << 2) | hdr->type2.cps_hi; + break; + case EGPRS_HDR_TYPE3: + bits = (hdr->type3.cps_lo << 2) | hdr->type3.cps_hi; + break; + default: + return -1; + } + + return egprs_get_cps(cps, type, bits); +} + +/* + * Decode EGPRS UL data section + * + * 1. Depuncture + * 2. Convolutional decoding + * 3. CRC check + * 4. Block combining (MCS-7,8,9 only) + */ +static int egprs_decode_data(uint8_t *l2_data, sbit_t *c, + int mcs, int p, int blk, int *n_errors, int *n_bits_total) +{ + ubit_t u[EGPRS_DATA_U_MAX]; + sbit_t C[EGPRS_DATA_C_MAX]; + + int i, j, rc, data_len; + struct gsm0503_mcs_code *code; + + if (blk && mcs < EGPRS_MCS7) { + /* Invalid MCS-X block state */ + return -1; + } + + code = &gsm0503_mcs_ul_codes[mcs]; + if (!code->data_punc[p]) { + /* Invalid MCS-X data puncture matrix */ + return -1; + } + + /* + * MCS-1,6 - single block processing + * MCS-7,9 - dual block processing + */ + if (mcs >= EGPRS_MCS7) + data_len = code->data_len / 2; + else + data_len = code->data_len; + + i = code->data_code_len - 1; + j = code->data_punc_len - 1; + + for (; i >= 0; i--) { + if (!code->data_punc[p][i]) + C[i] = c[j--]; + else + C[i] = 0; + } + + osmo_conv_decode_ber(code->data_conv, C, u, n_errors, n_bits_total); + rc = osmo_crc16gen_check_bits(&gsm0503_mcs_crc12, u, + data_len, u + data_len); + if (rc) + return -1; + + /* Offsets output pointer on the second block of Type 1 MCS */ + osmo_ubit2pbit_ext(l2_data, code->hdr_len + blk * data_len, + u, 0, data_len, 1); + + /* Return the number of bytes required for the bit message */ + return NUM_BYTES(code->hdr_len + code->data_len); +} + +/* + * Decode EGPRS UL message + * + * 1. Header section decoding + * 2. Extract CPS settings + * 3. Burst unmapping and deinterleaving + * 4. Data section decoding + */ +int gsm0503_pdtch_egprs_decode(uint8_t *l2_data, sbit_t *bursts, uint16_t nbits, + uint8_t *usf_p, int *n_errors, int *n_bits_total) +{ + sbit_t dc[EGPRS_DATA_DC_MAX]; + sbit_t c1[EGPRS_DATA_C1], c2[EGPRS_DATA_C2]; + int type, rc; + struct egprs_cps cps; + union gprs_rlc_ul_hdr_egprs *hdr; + + if ((nbits != GSM0503_GPRS_BURSTS_NBITS) && + (nbits != GSM0503_EGPRS_BURSTS_NBITS)) { + /* Invalid EGPRS bit length */ + return -1; + } + + hdr = (union gprs_rlc_ul_hdr_egprs *) l2_data; + type = egprs_decode_hdr(hdr, bursts, nbits); + if (egprs_parse_ul_cps(&cps, hdr, type) < 0) + return -1; + + switch (cps.mcs) { + case EGPRS_MCS1: + case EGPRS_MCS2: + case EGPRS_MCS3: + case EGPRS_MCS4: + egprs_type3_unmap(bursts, NULL, dc); + break; + case EGPRS_MCS5: + case EGPRS_MCS6: + egprs_type2_unmap(bursts, NULL, dc); + break; + case EGPRS_MCS7: + case EGPRS_MCS8: + case EGPRS_MCS9: + egprs_type1_unmap(bursts, NULL, c1, c2, cps.mcs); + break; + default: + /* Invalid MCS-X */ + return -1; + } + + /* Decode MCS-X block, where X = cps.mcs */ + if (cps.mcs < EGPRS_MCS7) { + rc = egprs_decode_data(l2_data, dc, cps.mcs, cps.p[0], + 0, n_errors, n_bits_total); + if (rc < 0) + return -1; + } else { + /* MCS-7,8,9 block 1 */ + rc = egprs_decode_data(l2_data, c1, cps.mcs, cps.p[0], + 0, n_errors, n_bits_total); + if (rc < 0) + return -1; + + /* MCS-7,8,9 block 2 */ + rc = egprs_decode_data(l2_data, c2, cps.mcs, cps.p[1], + 1, n_errors, n_bits_total); + if (rc < 0) + return -1; + } + + return rc; +} + +/* + * GSM PDTCH block transcoding + */ + +int gsm0503_pdtch_decode(uint8_t *l2_data, sbit_t *bursts, uint8_t *usf_p, + int *n_errors, int *n_bits_total) +{ + sbit_t iB[456], cB[676], hl_hn[8]; + ubit_t conv[456]; + int i, j, k, rv, best = 0, cs = 0, usf = 0; /* make GCC happy */ + + for (i = 0; i < 4; i++) + gsm0503_xcch_burst_unmap(&iB[i * 114], &bursts[i * 116], + hl_hn + i * 2, hl_hn + i * 2 + 1); + + for (i = 0; i < 4; i++) { + for (j = 0, k = 0; j < 8; j++) + k += abs(((int)gsm0503_pdtch_hl_hn_sbit[i][j]) - ((int)hl_hn[j])); + + if (i == 0 || k < best) { + best = k; + cs = i + 1; + } + } + + gsm0503_xcch_deinterleave(cB, iB); + + switch (cs) { + case 1: + osmo_conv_decode_ber(&gsm0503_xcch, cB, + conv, n_errors, n_bits_total); + + rv = osmo_crc64gen_check_bits(&gsm0503_fire_crc40, + conv, 184, conv + 184); + if (rv) + return -1; + + osmo_ubit2pbit_ext(l2_data, 0, conv, 0, 184, 1); + + return 23; + case 2: + for (i = 587, j = 455; i >= 0; i--) { + if (!gsm0503_puncture_cs2[i]) + cB[i] = cB[j--]; + else + cB[i] = 0; + } + + osmo_conv_decode_ber(&gsm0503_cs2_np, cB, + conv, n_errors, n_bits_total); + + for (i = 0; i < 8; i++) { + for (j = 0, k = 0; j < 6; j++) + k += abs(((int)gsm0503_usf2six[i][j]) - ((int)conv[j])); + + if (i == 0 || k < best) { + best = k; + usf = i; + } + } + + conv[3] = usf & 1; + conv[4] = (usf >> 1) & 1; + conv[5] = (usf >> 2) & 1; + if (usf_p) + *usf_p = usf; + + rv = osmo_crc16gen_check_bits(&gsm0503_cs234_crc16, + conv + 3, 271, conv + 3 + 271); + if (rv) + return -1; + + osmo_ubit2pbit_ext(l2_data, 0, conv, 3, 271, 1); + + return 34; + case 3: + for (i = 675, j = 455; i >= 0; i--) { + if (!gsm0503_puncture_cs3[i]) + cB[i] = cB[j--]; + else + cB[i] = 0; + } + + osmo_conv_decode_ber(&gsm0503_cs3_np, cB, + conv, n_errors, n_bits_total); + + for (i = 0; i < 8; i++) { + for (j = 0, k = 0; j < 6; j++) + k += abs(((int)gsm0503_usf2six[i][j]) - ((int)conv[j])); + + if (i == 0 || k < best) { + best = k; + usf = i; + } + } + + conv[3] = usf & 1; + conv[4] = (usf >> 1) & 1; + conv[5] = (usf >> 2) & 1; + if (usf_p) + *usf_p = usf; + + rv = osmo_crc16gen_check_bits(&gsm0503_cs234_crc16, + conv + 3, 315, conv + 3 + 315); + if (rv) + return -1; + + osmo_ubit2pbit_ext(l2_data, 0, conv, 3, 315, 1); + + return 40; + case 4: + for (i = 12; i < 456; i++) + conv[i] = (cB[i] < 0) ? 1 : 0; + + for (i = 0; i < 8; i++) { + for (j = 0, k = 0; j < 12; j++) + k += abs(((int)gsm0503_usf2twelve_sbit[i][j]) - ((int)cB[j])); + + if (i == 0 || k < best) { + best = k; + usf = i; + } + } + + conv[9] = usf & 1; + conv[10] = (usf >> 1) & 1; + conv[11] = (usf >> 2) & 1; + if (usf_p) + *usf_p = usf; + + rv = osmo_crc16gen_check_bits(&gsm0503_cs234_crc16, + conv + 9, 431, conv + 9 + 431); + if (rv) { + *n_bits_total = 456 - 12; + *n_errors = *n_bits_total; + return -1; + } + + *n_bits_total = 456 - 12; + *n_errors = 0; + + osmo_ubit2pbit_ext(l2_data, 0, conv, 9, 431, 1); + + return 54; + default: + *n_bits_total = 0; + *n_errors = 0; + break; + } + + return -1; +} + +/* + * EGPRS PDTCH UL block encoding + */ +static int egprs_type3_map(ubit_t *bursts, ubit_t *hc, ubit_t *dc, int usf) +{ + int i; + ubit_t iB[456]; + const ubit_t *hl_hn = gsm0503_pdtch_hl_hn_ubit[3]; + + gsm0503_mcs1_dl_interleave(gsm0503_usf2six[usf], hc, dc, iB); + + for (i = 0; i < 4; i++) { + gsm0503_xcch_burst_map(&iB[i * 114], &bursts[i * 116], + hl_hn + i * 2, hl_hn + i * 2 + 1); + } + + return 0; +} + +static int egprs_type2_map(ubit_t *bursts, ubit_t *hc, ubit_t *dc, int usf) +{ + int i; + const ubit_t *up; + ubit_t hi[EGPRS_HDR_HC_MAX]; + ubit_t di[EGPRS_DATA_DC_MAX]; + + gsm0503_mcs5_dl_interleave(hc, dc, hi, di); + up = gsm0503_mcs5_usf_precode_table[usf]; + + for (i = 0; i < 4; i++) { + gsm0503_mcs5_dl_burst_map(di, &bursts[i * 348], hi, up, i); + gsm0503_mcs5_burst_swap((sbit_t *) &bursts[i * 348]); + } + + return 0; +} + +static int egprs_type1_map(ubit_t *bursts, ubit_t *hc, + ubit_t *c1, ubit_t *c2, int usf, int mcs) +{ + int i; + const ubit_t *up; + ubit_t hi[EGPRS_HDR_HC_MAX]; + ubit_t di[EGPRS_DATA_C1 * 2]; + + if (mcs == EGPRS_MCS7) + gsm0503_mcs7_dl_interleave(hc, c1, c2, hi, di); + else + gsm0503_mcs8_dl_interleave(hc, c1, c2, hi, di); + + up = gsm0503_mcs5_usf_precode_table[usf]; + + for (i = 0; i < 4; i++) { + gsm0503_mcs7_dl_burst_map(di, &bursts[i * 348], hi, up, i); + gsm0503_mcs5_burst_swap((sbit_t *) &bursts[i * 348]); + } + + return 0; +} + +static int egprs_encode_hdr(ubit_t *hc, uint8_t *l2_data, int mcs) +{ + int i, j; + ubit_t upp[EGPRS_HDR_UPP_MAX], C[EGPRS_HDR_C_MAX]; + struct gsm0503_mcs_code *code; + + code = &gsm0503_mcs_dl_codes[mcs]; + + osmo_pbit2ubit_ext(upp, 0, l2_data, code->usf_len, code->hdr_len, 1); + osmo_crc8gen_set_bits(&gsm0503_mcs_crc8_hdr, upp, + code->hdr_len, upp + code->hdr_len); + + osmo_conv_encode(code->hdr_conv, upp, C); + + /* MCS-5,6 header direct puncture instead of table */ + if ((mcs == EGPRS_MCS5) || (mcs == EGPRS_MCS6)) { + memcpy(hc, C, code->hdr_code_len); + hc[99] = hc[98]; + return 0; + } + + if (!code->hdr_punc) { + /* Invalid MCS-X header puncture matrix */ + return -1; + } + + for (i = 0, j = 0; i < code->hdr_code_len; i++) { + if (!code->hdr_punc[i]) + hc[j++] = C[i]; + } + + return 0; +} + +static int egprs_encode_data(ubit_t *c, uint8_t *l2_data, + int mcs, int p, int blk) +{ + int i, j, data_len; + ubit_t u[EGPRS_DATA_U_MAX], C[EGPRS_DATA_C_MAX]; + struct gsm0503_mcs_code *code; + + code = &gsm0503_mcs_dl_codes[mcs]; + + /* + * Dual block - MCS-7,8,9 + * Single block - MCS-1,2,3,4,5,6 + */ + if (mcs >= EGPRS_MCS7) + data_len = code->data_len / 2; + else + data_len = code->data_len; + + osmo_pbit2ubit_ext(u, 0, l2_data, + code->usf_len + code->hdr_len + blk * data_len, data_len, 1); + + osmo_crc16gen_set_bits(&gsm0503_mcs_crc12, u, data_len, u + data_len); + + osmo_conv_encode(code->data_conv, u, C); + + if (!code->data_punc[p]) { + /* Invalid MCS-X data puncture matrix */ + return -1; + } + + for (i = 0, j = 0; i < code->data_code_len; i++) { + if (!code->data_punc[p][i]) + c[j++] = C[i]; + } + + return 0; +} + +/* + * Parse EGPRS DL header for coding and puncturing scheme (CPS) + * + * Type 1 - MCS-7,8,9 + * Type 2 - MCS-5,6 + * Type 3 - MCS-1,2,3,4 + */ +static int egprs_parse_dl_cps(struct egprs_cps *cps, + union gprs_rlc_dl_hdr_egprs *hdr, int type) +{ + uint8_t bits; + + switch (type) { + case EGPRS_HDR_TYPE1: + bits = hdr->type1.cps; + break; + case EGPRS_HDR_TYPE2: + bits = hdr->type2.cps; + break; + case EGPRS_HDR_TYPE3: + bits = hdr->type3.cps; + break; + default: + return -1; + } + + return egprs_get_cps(cps, type, bits); +} + +/* + * EGPRS DL message encoding + */ +int gsm0503_pdtch_egprs_encode(ubit_t *bursts, + uint8_t *l2_data, uint8_t l2_len) +{ + ubit_t hc[EGPRS_DATA_C_MAX], dc[EGPRS_DATA_DC_MAX]; + ubit_t c1[EGPRS_DATA_C1], c2[EGPRS_DATA_C2]; + uint8_t mcs; + struct egprs_cps cps; + union gprs_rlc_dl_hdr_egprs *hdr; + + switch (l2_len) { + case 27: + mcs = EGPRS_MCS1; + break; + case 33: + mcs = EGPRS_MCS2; + break; + case 42: + mcs = EGPRS_MCS3; + break; + case 49: + mcs = EGPRS_MCS4; + break; + case 60: + mcs = EGPRS_MCS5; + break; + case 78: + mcs = EGPRS_MCS6; + break; + case 118: + mcs = EGPRS_MCS7; + break; + case 142: + mcs = EGPRS_MCS8; + break; + case 154: + mcs = EGPRS_MCS9; + break; + default: + return -1; + } + + /* Read header for USF and puncturing matrix selection. */ + hdr = (union gprs_rlc_dl_hdr_egprs *) l2_data; + + switch (mcs) { + case EGPRS_MCS1: + case EGPRS_MCS2: + case EGPRS_MCS3: + case EGPRS_MCS4: + /* Check for valid CPS and matching MCS to message size */ + if ((egprs_parse_dl_cps(&cps, hdr, EGPRS_HDR_TYPE3) < 0) || + (cps.mcs != mcs)) + goto bad_header; + + egprs_encode_hdr(hc, l2_data, mcs); + egprs_encode_data(dc, l2_data, mcs, cps.p[0], 0); + egprs_type3_map(bursts, hc, dc, hdr->type3.usf); + break; + case EGPRS_MCS5: + case EGPRS_MCS6: + if ((egprs_parse_dl_cps(&cps, hdr, EGPRS_HDR_TYPE2) < 0) || + (cps.mcs != mcs)) + goto bad_header; + + egprs_encode_hdr(hc, l2_data, mcs); + egprs_encode_data(dc, l2_data, mcs, cps.p[0], 0); + egprs_type2_map(bursts, hc, dc, hdr->type2.usf); + break; + case EGPRS_MCS7: + case EGPRS_MCS8: + case EGPRS_MCS9: + if ((egprs_parse_dl_cps(&cps, hdr, EGPRS_HDR_TYPE1) < 0) || + (cps.mcs != mcs)) + goto bad_header; + + egprs_encode_hdr(hc, l2_data, mcs); + egprs_encode_data(c1, l2_data, mcs, cps.p[0], 0); + egprs_encode_data(c2, l2_data, mcs, cps.p[1], 1); + egprs_type1_map(bursts, hc, c1, c2, hdr->type1.usf, mcs); + break; + } + + return mcs >= EGPRS_MCS5 ? + GSM0503_EGPRS_BURSTS_NBITS : GSM0503_GPRS_BURSTS_NBITS; + +bad_header: + /* Invalid EGPRS MCS-X header */ + return -1; +} + +int gsm0503_pdtch_encode(ubit_t *bursts, uint8_t *l2_data, uint8_t l2_len) +{ + ubit_t iB[456], cB[676]; + const ubit_t *hl_hn; + ubit_t conv[334]; + int i, j, usf; + + switch (l2_len) { + case 23: + osmo_pbit2ubit_ext(conv, 0, l2_data, 0, 184, 1); + + osmo_crc64gen_set_bits(&gsm0503_fire_crc40, conv, 184, conv + 184); + + osmo_conv_encode(&gsm0503_xcch, conv, cB); + + hl_hn = gsm0503_pdtch_hl_hn_ubit[0]; + + break; + case 34: + osmo_pbit2ubit_ext(conv, 3, l2_data, 0, 271, 1); + usf = l2_data[0] & 0x7; + + osmo_crc16gen_set_bits(&gsm0503_cs234_crc16, conv + 3, + 271, conv + 3 + 271); + + memcpy(conv, gsm0503_usf2six[usf], 6); + + osmo_conv_encode(&gsm0503_cs2_np, conv, cB); + + for (i = 0, j = 0; i < 588; i++) + if (!gsm0503_puncture_cs2[i]) + cB[j++] = cB[i]; + + hl_hn = gsm0503_pdtch_hl_hn_ubit[1]; + + break; + case 40: + osmo_pbit2ubit_ext(conv, 3, l2_data, 0, 315, 1); + usf = l2_data[0] & 0x7; + + osmo_crc16gen_set_bits(&gsm0503_cs234_crc16, conv + 3, + 315, conv + 3 + 315); + + memcpy(conv, gsm0503_usf2six[usf], 6); + + osmo_conv_encode(&gsm0503_cs3_np, conv, cB); + + for (i = 0, j = 0; i < 676; i++) + if (!gsm0503_puncture_cs3[i]) + cB[j++] = cB[i]; + + hl_hn = gsm0503_pdtch_hl_hn_ubit[2]; + + break; + case 54: + osmo_pbit2ubit_ext(cB, 9, l2_data, 0, 431, 1); + usf = l2_data[0] & 0x7; + + osmo_crc16gen_set_bits(&gsm0503_cs234_crc16, cB + 9, + 431, cB + 9 + 431); + + memcpy(cB, gsm0503_usf2twelve_ubit[usf], 12); + + hl_hn = gsm0503_pdtch_hl_hn_ubit[3]; + + break; + default: + return -1; + } + + gsm0503_xcch_interleave(cB, iB); + + for (i = 0; i < 4; i++) { + gsm0503_xcch_burst_map(&iB[i * 114], &bursts[i * 116], + hl_hn + i * 2, hl_hn + i * 2 + 1); + } + + return GSM0503_GPRS_BURSTS_NBITS; +} + +/* + * GSM TCH/F FR/EFR transcoding + */ + +static void tch_fr_reassemble(uint8_t *tch_data, + ubit_t *b_bits, int net_order) +{ + int i, j, k, l, o; + + tch_data[0] = 0xd << 4; + memset(tch_data + 1, 0, 32); + + if (net_order) { + for (i = 0, j = 4; i < 260; i++, j++) + tch_data[j >> 3] |= (b_bits[i] << (7 - (j & 7))); + + return; + } + + /* reassemble d-bits */ + i = 0; /* counts bits */ + j = 4; /* counts output bits */ + k = gsm0503_gsm_fr_map[0]-1; /* current number bit in element */ + l = 0; /* counts element bits */ + o = 0; /* offset input bits */ + while (i < 260) { + tch_data[j >> 3] |= (b_bits[k + o] << (7 - (j & 7))); + if (--k < 0) { + o += gsm0503_gsm_fr_map[l]; + k = gsm0503_gsm_fr_map[++l]-1; + } + i++; + j++; + } +} + +static void tch_fr_disassemble(ubit_t *b_bits, + uint8_t *tch_data, int net_order) +{ + int i, j, k, l, o; + + if (net_order) { + for (i = 0, j = 4; i < 260; i++, j++) + b_bits[i] = (tch_data[j >> 3] >> (7 - (j & 7))) & 1; + + return; + } + + i = 0; /* counts bits */ + j = 4; /* counts input bits */ + k = gsm0503_gsm_fr_map[0] - 1; /* current number bit in element */ + l = 0; /* counts element bits */ + o = 0; /* offset output bits */ + while (i < 260) { + b_bits[k + o] = (tch_data[j >> 3] >> (7 - (j & 7))) & 1; + if (--k < 0) { + o += gsm0503_gsm_fr_map[l]; + k = gsm0503_gsm_fr_map[++l] - 1; + } + i++; + j++; + } +} + +static void tch_hr_reassemble(uint8_t *tch_data, ubit_t *b_bits) +{ + int i, j; + + tch_data[0] = 0x00; /* F = 0, FT = 000 */ + memset(tch_data + 1, 0, 14); + + for (i = 0, j = 8; i < 112; i++, j++) + tch_data[j >> 3] |= (b_bits[i] << (7 - (j & 7))); +} + +static void tch_hr_disassemble(ubit_t *b_bits, uint8_t *tch_data) +{ + int i, j; + + for (i = 0, j = 8; i < 112; i++, j++) + b_bits[i] = (tch_data[j >> 3] >> (7 - (j & 7))) & 1; +} + +static void tch_efr_reassemble(uint8_t *tch_data, ubit_t *b_bits) +{ + int i, j; + + tch_data[0] = 0xc << 4; + memset(tch_data + 1, 0, 30); + + for (i = 0, j = 4; i < 244; i++, j++) + tch_data[j >> 3] |= (b_bits[i] << (7 - (j & 7))); +} + +static void tch_efr_disassemble(ubit_t *b_bits, uint8_t *tch_data) +{ + int i, j; + + for (i = 0, j = 4; i < 244; i++, j++) + b_bits[i] = (tch_data[j >> 3] >> (7 - (j & 7))) & 1; +} + +static void tch_amr_reassemble(uint8_t *tch_data, ubit_t *d_bits, int len) +{ + int i, j; + + memset(tch_data, 0, (len + 7) >> 3); + + for (i = 0, j = 0; i < len; i++, j++) + tch_data[j >> 3] |= (d_bits[i] << (7 - (j & 7))); +} + +static void tch_amr_disassemble(ubit_t *d_bits, uint8_t *tch_data, int len) +{ + int i, j; + + for (i = 0, j = 0; i < len; i++, j++) + d_bits[i] = (tch_data[j >> 3] >> (7 - (j & 7))) & 1; +} + +static void tch_fr_d_to_b(ubit_t *b_bits, ubit_t *d_bits) +{ + int i; + + for (i = 0; i < 260; i++) + b_bits[gsm610_bitorder[i]] = d_bits[i]; +} + +static void tch_fr_b_to_d(ubit_t *d_bits, ubit_t *b_bits) +{ + int i; + + for (i = 0; i < 260; i++) + d_bits[i] = b_bits[gsm610_bitorder[i]]; +} + +static void tch_hr_d_to_b(ubit_t *b_bits, ubit_t *d_bits) +{ + int i; + + const uint16_t *map; + + if (!d_bits[93] && !d_bits[94]) + map = gsm620_unvoiced_bitorder; + else + map = gsm620_voiced_bitorder; + + for (i = 0; i < 112; i++) + b_bits[map[i]] = d_bits[i]; +} + +static void tch_hr_b_to_d(ubit_t *d_bits, ubit_t *b_bits) +{ + int i; + const uint16_t *map; + + if (!b_bits[34] && !b_bits[35]) + map = gsm620_unvoiced_bitorder; + else + map = gsm620_voiced_bitorder; + + for (i = 0; i < 112; i++) + d_bits[i] = b_bits[map[i]]; +} + +static void tch_efr_d_to_w(ubit_t *b_bits, ubit_t *d_bits) +{ + int i; + + for (i = 0; i < 260; i++) + b_bits[gsm660_bitorder[i]] = d_bits[i]; +} + +static void tch_efr_w_to_d(ubit_t *d_bits, ubit_t *b_bits) +{ + int i; + + for (i = 0; i < 260; i++) + d_bits[i] = b_bits[gsm660_bitorder[i]]; +} + +static void tch_efr_protected(ubit_t *s_bits, ubit_t *b_bits) +{ + int i; + + for (i = 0; i < 65; i++) + b_bits[i] = s_bits[gsm0503_gsm_efr_protected_bits[i] - 1]; +} + +static void tch_fr_unreorder(ubit_t *d, ubit_t *p, ubit_t *u) +{ + int i; + + for (i = 0; i < 91; i++) { + d[i << 1] = u[i]; + d[(i << 1) + 1] = u[184 - i]; + } + + for (i = 0; i < 3; i++) + p[i] = u[91 + i]; +} + +static void tch_fr_reorder(ubit_t *u, ubit_t *d, ubit_t *p) +{ + int i; + + for (i = 0; i < 91; i++) { + u[i] = d[i << 1]; + u[184 - i] = d[(i << 1) + 1]; + } + + for (i = 0; i < 3; i++) + u[91 + i] = p[i]; +} + +static void tch_hr_unreorder(ubit_t *d, ubit_t *p, ubit_t *u) +{ + memcpy(d, u, 95); + memcpy(p, u + 95, 3); +} + +static void tch_hr_reorder(ubit_t *u, ubit_t *d, ubit_t *p) +{ + memcpy(u, d, 95); + memcpy(u + 95, p, 3); +} + +static void tch_efr_reorder(ubit_t *w, ubit_t *s, ubit_t *p) +{ + memcpy(w, s, 71); + w[71] = w[72] = s[69]; + memcpy(w + 73, s + 71, 50); + w[123] = w[124] = s[119]; + memcpy(w + 125, s + 121, 53); + w[178] = w[179] = s[172]; + memcpy(w + 180, s + 174, 50); + w[230] = w[231] = s[222]; + memcpy(w + 232, s + 224, 20); + memcpy(w + 252, p, 8); +} + +static void tch_efr_unreorder(ubit_t *s, ubit_t *p, ubit_t *w) +{ + int sum; + + memcpy(s, w, 71); + sum = s[69] + w[71] + w[72]; + s[69] = (sum > 2); + memcpy(s + 71, w + 73, 50); + sum = s[119] + w[123] + w[124]; + s[119] = (sum > 2); + memcpy(s + 121, w + 125, 53); + sum = s[172] + w[178] + w[179]; + s[172] = (sum > 2); + memcpy(s + 174, w + 180, 50); + sum = s[220] + w[230] + w[231]; + s[222] = (sum > 2); + memcpy(s + 224, w + 232, 20); + memcpy(p, w + 252, 8); +} + +static void tch_amr_merge(ubit_t *u, ubit_t *d, ubit_t *p, int len, int prot) +{ + memcpy(u, d, prot); + memcpy(u + prot, p, 6); + memcpy(u + prot + 6, d + prot, len - prot); +} + +static void tch_amr_unmerge(ubit_t *d, ubit_t *p, + ubit_t *u, int len, int prot) +{ + memcpy(d, u, prot); + memcpy(p, u + prot, 6); + memcpy(d + prot, u + prot + 6, len - prot); +} + +int gsm0503_tch_fr_decode(uint8_t *tch_data, sbit_t *bursts, + int net_order, int efr, int *n_errors, int *n_bits_total) +{ + sbit_t iB[912], cB[456], h; + ubit_t conv[185], s[244], w[260], b[65], d[260], p[8]; + int i, rv, len, steal = 0; + + for (i = 0; i < 8; i++) { + gsm0503_tch_burst_unmap(&iB[i * 114], + &bursts[i * 116], &h, i >> 2); + steal -= h; + } + + gsm0503_tch_fr_deinterleave(cB, iB); + + if (steal > 0) { + rv = _xcch_decode_cB(tch_data, cB, n_errors, n_bits_total); + if (rv) { + /* Error decoding FACCH frame */ + return -1; + } + + return 23; + } + + osmo_conv_decode_ber(&gsm0503_tch_fr, cB, conv, n_errors, n_bits_total); + + tch_fr_unreorder(d, p, conv); + + for (i = 0; i < 78; i++) + d[i + 182] = (cB[i + 378] < 0) ? 1 : 0; + + rv = osmo_crc8gen_check_bits(&gsm0503_tch_fr_crc3, d, 50, p); + if (rv) { + /* Error checking CRC8 for the FR part of an EFR/FR frame */ + return -1; + } + + if (efr) { + tch_efr_d_to_w(w, d); + + tch_efr_unreorder(s, p, w); + + tch_efr_protected(s, b); + + rv = osmo_crc8gen_check_bits(&gsm0503_tch_efr_crc8, b, 65, p); + if (rv) { + /* Error checking CRC8 for the EFR part of an EFR frame */ + return -1; + } + + tch_efr_reassemble(tch_data, s); + + len = GSM_EFR_BYTES; + } else { + tch_fr_d_to_b(w, d); + + tch_fr_reassemble(tch_data, w, net_order); + + len = GSM_FR_BYTES; + } + + return len; +} + +int gsm0503_tch_fr_encode(ubit_t *bursts, uint8_t *tch_data, + int len, int net_order) +{ + ubit_t iB[912], cB[456], h; + ubit_t conv[185], w[260], b[65], s[244], d[260], p[8]; + int i; + + switch (len) { + case GSM_EFR_BYTES: /* TCH EFR */ + + tch_efr_disassemble(s, tch_data); + + tch_efr_protected(s, b); + + osmo_crc8gen_set_bits(&gsm0503_tch_efr_crc8, b, 65, p); + + tch_efr_reorder(w, s, p); + + tch_efr_w_to_d(d, w); + + goto coding_efr_fr; + case GSM_FR_BYTES: /* TCH FR */ + tch_fr_disassemble(w, tch_data, net_order); + + tch_fr_b_to_d(d, w); + +coding_efr_fr: + osmo_crc8gen_set_bits(&gsm0503_tch_fr_crc3, d, 50, p); + + tch_fr_reorder(conv, d, p); + + memcpy(cB + 378, d + 182, 78); + + osmo_conv_encode(&gsm0503_tch_fr, conv, cB); + + h = 0; + + break; + case GSM_MACBLOCK_LEN: /* FACCH */ + _xcch_encode_cB(cB, tch_data); + + h = 1; + + break; + default: + return -1; + } + + gsm0503_tch_fr_interleave(cB, iB); + + for (i = 0; i < 8; i++) { + gsm0503_tch_burst_map(&iB[i * 114], + &bursts[i * 116], &h, i >> 2); + } + + return 0; +} + +int gsm0503_tch_hr_decode(uint8_t *tch_data, sbit_t *bursts, int odd, + int *n_errors, int *n_bits_total) +{ + sbit_t iB[912], cB[456], h; + ubit_t conv[98], b[112], d[112], p[3]; + int i, rv, steal = 0; + + /* Only unmap the stealing bits */ + if (!odd) { + for (i = 0; i < 4; i++) { + gsm0503_tch_burst_unmap(NULL, &bursts[i * 116], &h, 0); + steal -= h; + } + + for (i = 2; i < 5; i++) { + gsm0503_tch_burst_unmap(NULL, &bursts[i * 116], &h, 1); + steal -= h; + } + } + + /* If we found a stole FACCH, but only at correct alignment */ + if (steal > 0) { + for (i = 0; i < 6; i++) { + gsm0503_tch_burst_unmap(&iB[i * 114], + &bursts[i * 116], NULL, i >> 2); + } + + for (i = 2; i < 4; i++) { + gsm0503_tch_burst_unmap(&iB[i * 114 + 456], + &bursts[i * 116], NULL, 1); + } + + gsm0503_tch_fr_deinterleave(cB, iB); + + rv = _xcch_decode_cB(tch_data, cB, n_errors, n_bits_total); + if (rv) { + /* Error decoding FACCH frame */ + return -1; + } + + return GSM_MACBLOCK_LEN; + } + + for (i = 0; i < 4; i++) { + gsm0503_tch_burst_unmap(&iB[i * 114], + &bursts[i * 116], NULL, i >> 1); + } + + gsm0503_tch_hr_deinterleave(cB, iB); + + osmo_conv_decode_ber(&gsm0503_tch_hr, cB, conv, n_errors, n_bits_total); + + tch_hr_unreorder(d, p, conv); + + for (i = 0; i < 17; i++) + d[i + 95] = (cB[i + 211] < 0) ? 1 : 0; + + rv = osmo_crc8gen_check_bits(&gsm0503_tch_fr_crc3, d + 73, 22, p); + if (rv) { + /* Error checking CRC8 for an HR frame */ + return -1; + } + + tch_hr_d_to_b(b, d); + + tch_hr_reassemble(tch_data, b); + + return 15; +} + +int gsm0503_tch_hr_encode(ubit_t *bursts, uint8_t *tch_data, int len) +{ + ubit_t iB[912], cB[456], h; + ubit_t conv[98], b[112], d[112], p[3]; + int i; + + switch (len) { + case 15: /* TCH HR */ + tch_hr_disassemble(b, tch_data); + + tch_hr_b_to_d(d, b); + + osmo_crc8gen_set_bits(&gsm0503_tch_fr_crc3, d + 73, 22, p); + + tch_hr_reorder(conv, d, p); + + osmo_conv_encode(&gsm0503_tch_hr, conv, cB); + + memcpy(cB + 211, d + 95, 17); + + h = 0; + + gsm0503_tch_hr_interleave(cB, iB); + + for (i = 0; i < 4; i++) { + gsm0503_tch_burst_map(&iB[i * 114], + &bursts[i * 116], &h, i >> 1); + } + + break; + case GSM_MACBLOCK_LEN: /* FACCH */ + _xcch_encode_cB(cB, tch_data); + + h = 1; + + gsm0503_tch_fr_interleave(cB, iB); + + for (i = 0; i < 6; i++) { + gsm0503_tch_burst_map(&iB[i * 114], + &bursts[i * 116], &h, i >> 2); + } + + for (i = 2; i < 4; i++) { + gsm0503_tch_burst_map(&iB[i * 114 + 456], + &bursts[i * 116], &h, 1); + } + + break; + default: + return -1; + } + + return 0; +} + +int gsm0503_tch_afs_decode(uint8_t *tch_data, sbit_t *bursts, + int codec_mode_req, uint8_t *codec, int codecs, uint8_t *ft, + uint8_t *cmr, int *n_errors, int *n_bits_total) +{ + sbit_t iB[912], cB[456], h; + ubit_t d[244], p[6], conv[250]; + int i, j, k, best = 0, rv, len, steal = 0, id = 0; + *n_errors = 0; *n_bits_total = 0; + + for (i=0; i<8; i++) { + gsm0503_tch_burst_unmap(&iB[i * 114], &bursts[i * 116], &h, i >> 2); + steal -= h; + } + + gsm0503_tch_fr_deinterleave(cB, iB); + + if (steal > 0) { + rv = _xcch_decode_cB(tch_data, cB, n_errors, n_bits_total); + if (rv) { + /* Error decoding FACCH frame */ + return -1; + } + + return GSM_MACBLOCK_LEN; + } + + for (i = 0; i < 4; i++) { + for (j = 0, k = 0; j < 8; j++) + k += abs(((int)gsm0503_afs_ic_sbit[i][j]) - ((int)cB[j])); + + if (i == 0 || k < best) { + best = k; + id = i; + } + } + + /* Check if indicated codec fits into range of codecs */ + if (id >= codecs) { + /* Codec mode out of range, return id */ + return id; + } + + switch ((codec_mode_req) ? codec[*ft] : codec[id]) { + case 7: /* TCH/AFS12.2 */ + osmo_conv_decode_ber(&gsm0503_tch_afs_12_2, cB + 8, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 244, 81); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 81, p); + if (rv) { + /* Error checking CRC8 for an AMR 12.2 frame */ + return -1; + } + + tch_amr_reassemble(tch_data, d, 244); + + len = 31; + + break; + case 6: /* TCH/AFS10.2 */ + osmo_conv_decode_ber(&gsm0503_tch_afs_10_2, cB + 8, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 204, 65); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 65, p); + if (rv) { + /* Error checking CRC8 for an AMR 10.2 frame */ + return -1; + } + + tch_amr_reassemble(tch_data, d, 204); + + len = 26; + + break; + case 5: /* TCH/AFS7.95 */ + osmo_conv_decode_ber(&gsm0503_tch_afs_7_95, cB + 8, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 159, 75); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 75, p); + if (rv) { + /* Error checking CRC8 for an AMR 7.95 frame */ + return -1; + } + + tch_amr_reassemble(tch_data, d, 159); + + len = 20; + + break; + case 4: /* TCH/AFS7.4 */ + osmo_conv_decode_ber(&gsm0503_tch_afs_7_4, cB + 8, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 148, 61); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 61, p); + if (rv) { + /* Error checking CRC8 for an AMR 7.4 frame */ + return -1; + } + + tch_amr_reassemble(tch_data, d, 148); + + len = 19; + + break; + case 3: /* TCH/AFS6.7 */ + osmo_conv_decode_ber(&gsm0503_tch_afs_6_7, cB + 8, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 134, 55); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 55, p); + if (rv) { + /* Error checking CRC8 for an AMR 6.7 frame */ + return -1; + } + + tch_amr_reassemble(tch_data, d, 134); + + len = 17; + + break; + case 2: /* TCH/AFS5.9 */ + osmo_conv_decode_ber(&gsm0503_tch_afs_5_9, cB + 8, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 118, 55); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 55, p); + if (rv) { + /* Error checking CRC8 for an AMR 5.9 frame */ + return -1; + } + + tch_amr_reassemble(tch_data, d, 118); + + len = 15; + + break; + case 1: /* TCH/AFS5.15 */ + osmo_conv_decode_ber(&gsm0503_tch_afs_5_15, cB + 8, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 103, 49); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 49, p); + if (rv) { + /* Error checking CRC8 for an AMR 5.15 frame */ + return -1; + } + + tch_amr_reassemble(tch_data, d, 103); + + len = 13; + + break; + case 0: /* TCH/AFS4.75 */ + osmo_conv_decode_ber(&gsm0503_tch_afs_4_75, cB + 8, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 95, 39); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 39, p); + if (rv) { + /* Error checking CRC8 for an AMR 4.75 frame */ + return -1; + } + + tch_amr_reassemble(tch_data, d, 95); + + len = 12; + + break; + default: + /* Unknown frame type */ + *n_bits_total = 448; + *n_errors = *n_bits_total; + return -1; + } + + /* Change codec request / indication, if frame is valid */ + if (codec_mode_req) + *cmr = id; + else + *ft = id; + + return len; +} + +int gsm0503_tch_afs_encode(ubit_t *bursts, uint8_t *tch_data, int len, + int codec_mode_req, uint8_t *codec, int codecs, uint8_t ft, + uint8_t cmr) +{ + ubit_t iB[912], cB[456], h; + ubit_t d[244], p[6], conv[250]; + int i; + uint8_t id; + + if (len == GSM_MACBLOCK_LEN) { /* FACCH */ + _xcch_encode_cB(cB, tch_data); + + h = 1; + + goto facch; + } + + h = 0; + + if (codec_mode_req) { + if (cmr >= codecs) { + /* FIXME: CMR ID is not in codec list! */ + return -1; + } + id = cmr; + } else { + if (ft >= codecs) { + /* FIXME: FT ID is not in codec list! */ + return -1; + } + id = ft; + } + + switch (codec[ft]) { + case 7: /* TCH/AFS12.2 */ + if (len != 31) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 244); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 81, p); + + tch_amr_merge(conv, d, p, 244, 81); + + osmo_conv_encode(&gsm0503_tch_afs_12_2, conv, cB + 8); + + break; + case 6: /* TCH/AFS10.2 */ + if (len != 26) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 204); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 65, p); + + tch_amr_merge(conv, d, p, 204, 65); + + osmo_conv_encode(&gsm0503_tch_afs_10_2, conv, cB + 8); + + break; + case 5: /* TCH/AFS7.95 */ + if (len != 20) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 159); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 75, p); + + tch_amr_merge(conv, d, p, 159, 75); + + osmo_conv_encode(&gsm0503_tch_afs_7_95, conv, cB + 8); + + break; + case 4: /* TCH/AFS7.4 */ + if (len != 19) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 148); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 61, p); + + tch_amr_merge(conv, d, p, 148, 61); + + osmo_conv_encode(&gsm0503_tch_afs_7_4, conv, cB + 8); + + break; + case 3: /* TCH/AFS6.7 */ + if (len != 17) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 134); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 55, p); + + tch_amr_merge(conv, d, p, 134, 55); + + osmo_conv_encode(&gsm0503_tch_afs_6_7, conv, cB + 8); + + break; + case 2: /* TCH/AFS5.9 */ + if (len != 15) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 118); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 55, p); + + tch_amr_merge(conv, d, p, 118, 55); + + osmo_conv_encode(&gsm0503_tch_afs_5_9, conv, cB + 8); + + break; + case 1: /* TCH/AFS5.15 */ + if (len != 13) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 103); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 49, p); + + tch_amr_merge(conv, d, p, 103, 49); + + osmo_conv_encode(&gsm0503_tch_afs_5_15, conv, cB + 8); + + break; + case 0: /* TCH/AFS4.75 */ + if (len != 12) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 95); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 39, p); + + tch_amr_merge(conv, d, p, 95, 39); + + osmo_conv_encode(&gsm0503_tch_afs_4_75, conv, cB + 8); + + break; + default: + /* FIXME: FT %ft is not supported */ + return -1; + } + + memcpy(cB, gsm0503_afs_ic_ubit[id], 8); + +facch: + gsm0503_tch_fr_interleave(cB, iB); + + for (i = 0; i < 8; i++) { + gsm0503_tch_burst_map(&iB[i * 114], + &bursts[i * 116], &h, i >> 2); + } + + return 0; + +invalid_length: + /* FIXME: payload length %len does not comply with codec type %ft */ + return -1; +} + +int gsm0503_tch_ahs_decode(uint8_t *tch_data, sbit_t *bursts, int odd, + int codec_mode_req, uint8_t *codec, int codecs, uint8_t *ft, + uint8_t *cmr, int *n_errors, int *n_bits_total) +{ + sbit_t iB[912], cB[456], h; + ubit_t d[244], p[6], conv[135]; + int i, j, k, best = 0, rv, len, steal = 0, id = 0; + + /* only unmap the stealing bits */ + if (!odd) { + for (i = 0; i < 4; i++) { + gsm0503_tch_burst_unmap(NULL, &bursts[i * 116], &h, 0); + steal -= h; + } + for (i = 2; i < 5; i++) { + gsm0503_tch_burst_unmap(NULL, &bursts[i * 116], &h, 1); + steal -= h; + } + } + + /* if we found a stole FACCH, but only at correct alignment */ + if (steal > 0) { + for (i = 0; i < 6; i++) { + gsm0503_tch_burst_unmap(&iB[i * 114], + &bursts[i * 116], NULL, i >> 2); + } + + for (i = 2; i < 4; i++) { + gsm0503_tch_burst_unmap(&iB[i * 114 + 456], + &bursts[i * 116], NULL, 1); + } + + gsm0503_tch_fr_deinterleave(cB, iB); + + rv = _xcch_decode_cB(tch_data, cB, n_errors, n_bits_total); + if (rv) { + /* Error decoding FACCH frame */ + return -1; + } + + return GSM_MACBLOCK_LEN; + } + + for (i = 0; i < 4; i++) { + gsm0503_tch_burst_unmap(&iB[i * 114], + &bursts[i * 116], NULL, i >> 1); + } + + gsm0503_tch_hr_deinterleave(cB, iB); + + for (i = 0; i < 4; i++) { + for (j = 0, k = 0; j < 4; j++) + k += abs(((int)gsm0503_ahs_ic_sbit[i][j]) - ((int)cB[j])); + + if (i == 0 || k < best) { + best = k; + id = i; + } + } + + /* Check if indicated codec fits into range of codecs */ + if (id >= codecs) { + /* Codec mode out of range, return id */ + return id; + } + + switch ((codec_mode_req) ? codec[*ft] : codec[id]) { + case 5: /* TCH/AHS7.95 */ + osmo_conv_decode_ber(&gsm0503_tch_ahs_7_95, cB + 4, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 123, 67); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 67, p); + if (rv) { + /* Error checking CRC8 for an AMR 7.95 frame */ + return -1; + } + + for (i = 0; i < 36; i++) + d[i + 123] = (cB[i + 192] < 0) ? 1 : 0; + + tch_amr_reassemble(tch_data, d, 159); + + len = 20; + + break; + case 4: /* TCH/AHS7.4 */ + osmo_conv_decode_ber(&gsm0503_tch_ahs_7_4, cB + 4, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 120, 61); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 61, p); + if (rv) { + /* Error checking CRC8 for an AMR 7.4 frame */ + return -1; + } + + for (i = 0; i < 28; i++) + d[i + 120] = (cB[i + 200] < 0) ? 1 : 0; + + tch_amr_reassemble(tch_data, d, 148); + + len = 19; + + break; + case 3: /* TCH/AHS6.7 */ + osmo_conv_decode_ber(&gsm0503_tch_ahs_6_7, cB + 4, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 110, 55); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 55, p); + if (rv) { + /* Error checking CRC8 for an AMR 6.7 frame */ + return -1; + } + + for (i = 0; i < 24; i++) + d[i + 110] = (cB[i + 204] < 0) ? 1 : 0; + + tch_amr_reassemble(tch_data, d, 134); + + len = 17; + + break; + case 2: /* TCH/AHS5.9 */ + osmo_conv_decode_ber(&gsm0503_tch_ahs_5_9, cB + 4, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 102, 55); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 55, p); + if (rv) { + /* Error checking CRC8 for an AMR 5.9 frame */ + return -1; + } + + for (i = 0; i < 16; i++) + d[i + 102] = (cB[i + 212] < 0) ? 1 : 0; + + tch_amr_reassemble(tch_data, d, 118); + + len = 15; + + break; + case 1: /* TCH/AHS5.15 */ + osmo_conv_decode_ber(&gsm0503_tch_ahs_5_15, cB + 4, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 91, 49); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 49, p); + if (rv) { + /* Error checking CRC8 for an AMR 5.15 frame */ + return -1; + } + + for (i = 0; i < 12; i++) + d[i + 91] = (cB[i + 216] < 0) ? 1 : 0; + + tch_amr_reassemble(tch_data, d, 103); + + len = 13; + + break; + case 0: /* TCH/AHS4.75 */ + osmo_conv_decode_ber(&gsm0503_tch_ahs_4_75, cB + 4, + conv, n_errors, n_bits_total); + + tch_amr_unmerge(d, p, conv, 83, 39); + + rv = osmo_crc8gen_check_bits(&gsm0503_amr_crc6, d, 39, p); + if (rv) { + /* Error checking CRC8 for an AMR 4.75 frame */ + return -1; + } + + for (i = 0; i < 12; i++) + d[i + 83] = (cB[i + 216] < 0) ? 1 : 0; + + tch_amr_reassemble(tch_data, d, 95); + + len = 12; + + break; + default: + /* Unknown frame type */ + *n_bits_total = 159; + *n_errors = *n_bits_total; + return -1; + } + + /* Change codec request / indication, if frame is valid */ + if (codec_mode_req) + *cmr = id; + else + *ft = id; + + return len; +} + +int gsm0503_tch_ahs_encode(ubit_t *bursts, uint8_t *tch_data, int len, + int codec_mode_req, uint8_t *codec, int codecs, uint8_t ft, + uint8_t cmr) +{ + ubit_t iB[912], cB[456], h; + ubit_t d[244], p[6], conv[135]; + int i; + uint8_t id; + + if (len == GSM_MACBLOCK_LEN) { /* FACCH */ + _xcch_encode_cB(cB, tch_data); + + h = 1; + + gsm0503_tch_fr_interleave(cB, iB); + + for (i = 0; i < 6; i++) + gsm0503_tch_burst_map(&iB[i * 114], &bursts[i * 116], + &h, i >> 2); + for (i = 2; i < 4; i++) + gsm0503_tch_burst_map(&iB[i * 114 + 456], + &bursts[i * 116], &h, 1); + + return 0; + } + + h = 0; + + if (codec_mode_req) { + if (cmr >= codecs) { + /* FIXME: CMR ID %d not in codec list */ + return -1; + } + id = cmr; + } else { + if (ft >= codecs) { + /* FIXME: FT ID %d not in codec list */ + return -1; + } + id = ft; + } + + switch (codec[ft]) { + case 5: /* TCH/AHS7.95 */ + if (len != 20) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 159); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 67, p); + + tch_amr_merge(conv, d, p, 123, 67); + + osmo_conv_encode(&gsm0503_tch_ahs_7_95, conv, cB + 4); + + memcpy(cB + 192, d + 123, 36); + + break; + case 4: /* TCH/AHS7.4 */ + if (len != 19) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 148); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 61, p); + + tch_amr_merge(conv, d, p, 120, 61); + + osmo_conv_encode(&gsm0503_tch_ahs_7_4, conv, cB + 4); + + memcpy(cB + 200, d + 120, 28); + + break; + case 3: /* TCH/AHS6.7 */ + if (len != 17) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 134); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 55, p); + + tch_amr_merge(conv, d, p, 110, 55); + + osmo_conv_encode(&gsm0503_tch_ahs_6_7, conv, cB + 4); + + memcpy(cB + 204, d + 110, 24); + + break; + case 2: /* TCH/AHS5.9 */ + if (len != 15) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 118); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 55, p); + + tch_amr_merge(conv, d, p, 102, 55); + + osmo_conv_encode(&gsm0503_tch_ahs_5_9, conv, cB + 4); + + memcpy(cB + 212, d + 102, 16); + + break; + case 1: /* TCH/AHS5.15 */ + if (len != 13) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 103); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 49, p); + + tch_amr_merge(conv, d, p, 91, 49); + + osmo_conv_encode(&gsm0503_tch_ahs_5_15, conv, cB + 4); + + memcpy(cB + 216, d + 91, 12); + + break; + case 0: /* TCH/AHS4.75 */ + if (len != 12) + goto invalid_length; + + tch_amr_disassemble(d, tch_data, 95); + + osmo_crc8gen_set_bits(&gsm0503_amr_crc6, d, 39, p); + + tch_amr_merge(conv, d, p, 83, 39); + + osmo_conv_encode(&gsm0503_tch_ahs_4_75, conv, cB + 4); + + memcpy(cB + 216, d + 83, 12); + + break; + default: + /* FIXME: FT %ft is not supported */ + return -1; + } + + memcpy(cB, gsm0503_afs_ic_ubit[id], 4); + + gsm0503_tch_hr_interleave(cB, iB); + + for (i = 0; i < 4; i++) + gsm0503_tch_burst_map(&iB[i * 114], &bursts[i * 116], &h, i >> 1); + + return 0; + +invalid_length: + /* FIXME: payload length %len does not comply with codec type %ft */ + return -1; +} + +/* + * GSM RACH transcoding + */ + +/* + * GSM RACH apply BSIC to parity + * + * p(j) = p(j) xor b(j) j = 0, ..., 5 + * b(0) = MSB of PLMN colour code + * b(5) = LSB of BS colour code + */ +static int rach_apply_bsic(ubit_t *d, uint8_t bsic) +{ + int i; + + /* Apply it */ + for (i = 0; i < 6; i++) + d[8 + i] ^= ((bsic >> (5 - i)) & 1); + + return 0; +} + +int gsm0503_rach_decode(uint8_t *ra, sbit_t *burst, uint8_t bsic) +{ + ubit_t conv[14]; + int rv; + + osmo_conv_decode(&gsm0503_rach, burst, conv); + + rach_apply_bsic(conv, bsic); + + rv = osmo_crc8gen_check_bits(&gsm0503_rach_crc6, conv, 8, conv + 8); + if (rv) + return -1; + + osmo_ubit2pbit_ext(ra, 0, conv, 0, 8, 1); + + return 0; +} + +int gsm0503_rach_encode(ubit_t *burst, uint8_t *ra, uint8_t bsic) +{ + ubit_t conv[14]; + + osmo_pbit2ubit_ext(conv, 0, ra, 0, 8, 1); + + osmo_crc8gen_set_bits(&gsm0503_rach_crc6, conv, 8, conv + 8); + + rach_apply_bsic(conv, bsic); + + osmo_conv_encode(&gsm0503_rach, conv, burst); + + return 0; +} + +/* + * GSM SCH transcoding + */ +int gsm0503_sch_decode(uint8_t *sb_info, sbit_t *burst) +{ + ubit_t conv[35]; + int rv; + + osmo_conv_decode(&gsm0503_sch, burst, conv); + + rv = osmo_crc16gen_check_bits(&gsm0503_sch_crc10, conv, 25, conv + 25); + if (rv) + return -1; + + osmo_ubit2pbit_ext(sb_info, 0, conv, 0, 25, 1); + + return 0; +} + +int gsm0503_sch_encode(ubit_t *burst, uint8_t *sb_info) +{ + ubit_t conv[35]; + + osmo_pbit2ubit_ext(conv, 0, sb_info, 0, 25, 1); + + osmo_crc16gen_set_bits(&gsm0503_sch_crc10, conv, 25, conv + 25); + + osmo_conv_encode(&gsm0503_sch, conv, burst); + + return 0; +} diff --git a/src/coding/gsm0503_interleaving.c b/src/coding/gsm0503_interleaving.c new file mode 100644 index 00000000..22ad6f69 --- /dev/null +++ b/src/coding/gsm0503_interleaving.c @@ -0,0 +1,573 @@ +/* + * (C) 2013 by Andreas Eversberg + * (C) 2016 by Tom Tsou + * + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include +#include + +#include +#include +#include + +/* + * GSM xCCH interleaving and burst mapping + * + * Interleaving: + * + * Given 456 coded input bits, form 4 blocks of 114 bits: + * + * i(B, j) = c(n, k) k = 0, ..., 455 + * n = 0, ..., N, N + 1, ... + * B = B_0 + 4n + (k mod 4) + * j = 2(49k mod 57) + ((k mod 8) div 4) + * + * Mapping on Burst: + * + * e(B, j) = i(B, j) + * e(B, 59 + j) = i(B, 57 + j) j = 0, ..., 56 + * e(B, 57) = h_l(B) + * e(B, 58) = h_n(B) + * + * Where hl(B) and hn(B) are bits in burst B indicating flags. + */ + +void gsm0503_xcch_deinterleave(sbit_t *cB, const sbit_t *iB) +{ + int j, k, B; + + for (k = 0; k < 456; k++) { + B = k & 3; + j = 2 * ((49 * k) % 57) + ((k & 7) >> 2); + cB[k] = iB[B * 114 + j]; + } +} + +void gsm0503_xcch_interleave(ubit_t *cB, ubit_t *iB) +{ + int j, k, B; + + for (k = 0; k < 456; k++) { + B = k & 3; + j = 2 * ((49 * k) % 57) + ((k & 7) >> 2); + iB[B * 114 + j] = cB[k]; + } +} + +void gsm0503_mcs1_dl_deinterleave(sbit_t *u, sbit_t *hc, + sbit_t *dc, const sbit_t *iB) +{ + int k; + sbit_t c[452]; + sbit_t cp[456]; + + gsm0503_xcch_deinterleave(cp, iB); + + for (k = 0; k < 25; k++) + c[k] = cp[k]; + for (k = 26; k < 82; k++) + c[k - 1] = cp[k]; + for (k = 83; k < 139; k++) + c[k - 2] = cp[k]; + for (k = 140; k < 424; k++) + c[k - 3] = cp[k]; + for (k = 425; k < 456; k++) + c[k - 4] = cp[k]; + + if (u) { + for (k = 0; k < 12; k++) + u[k] = c[k]; + } + + if (hc) { + for (k = 12; k < 80; k++) + hc[k - 12] = c[k]; + } + + if (dc) { + for (k = 80; k < 452; k++) + dc[k - 80] = c[k]; + } +} + +void gsm0503_mcs1_dl_interleave(const ubit_t *up, const ubit_t *hc, + const ubit_t *dc, ubit_t *iB) +{ + int k; + ubit_t c[452]; + ubit_t cp[456]; + + for (k = 0; k < 12; k++) + c[k] = up[k]; + for (k = 12; k < 80; k++) + c[k] = hc[k - 12]; + for (k = 80; k < 452; k++) + c[k] = dc[k - 80]; + + for (k = 0; k < 25; k++) + cp[k] = c[k]; + for (k = 26; k < 82; k++) + cp[k] = c[k - 1]; + for (k = 83; k < 139; k++) + cp[k] = c[k - 2]; + for (k = 140; k < 424; k++) + cp[k] = c[k - 3]; + for (k = 425; k < 456; k++) + cp[k] = c[k - 4]; + + cp[25] = 0; + cp[82] = 0; + cp[139] = 0; + cp[424] = 0; + + gsm0503_xcch_interleave(cp, iB); +} + +void gsm0503_mcs1_ul_deinterleave(sbit_t *hc, sbit_t *dc, const sbit_t *iB) +{ + int k; + sbit_t c[452]; + sbit_t cp[456]; + + gsm0503_xcch_deinterleave(cp, iB); + + for (k = 0; k < 25; k++) + c[k] = cp[k]; + for (k = 26; k < 82; k++) + c[k - 1] = cp[k]; + for (k = 83; k < 139; k++) + c[k - 2] = cp[k]; + for (k = 140; k < 424; k++) + c[k - 3] = cp[k]; + for (k = 425; k < 456; k++) + c[k - 4] = cp[k]; + + if (hc) { + for (k = 0; k < 80; k++) + hc[k] = c[k]; + } + + if (dc) { + for (k = 80; k < 452; k++) + dc[k - 80] = c[k]; + } +} + +voi