From 9407e644b0246fadec74a45faeedb570a0c04c6b Mon Sep 17 00:00:00 2001 From: Tom Tsou Date: Wed, 6 Jul 2016 13:29:55 -0700 Subject: trx: Add EGPRS coding and decoding procedures Handles uplink decoding and downlink encoding procedures for MCS 1-9. Includes Type 1, 2, and 3 headers and tables from 3GPP TS 44.060 in order to independently recover coding and puncturing scheme (CPS) parameters for each coded message. Change-Id: I0f059ae34c6f36179553cbc972f8becf8179eb55 Signed-off-by: Tom Tsou --- src/osmo-bts-trx/gsm0503_coding.c | 1014 ++++++++++++++++++++++++++++++++++++- src/osmo-bts-trx/gsm0503_coding.h | 22 + 2 files changed, 1028 insertions(+), 8 deletions(-) diff --git a/src/osmo-bts-trx/gsm0503_coding.c b/src/osmo-bts-trx/gsm0503_coding.c index fde020e1..fd863851 100644 --- a/src/osmo-bts-trx/gsm0503_coding.c +++ b/src/osmo-bts-trx/gsm0503_coding.c @@ -1,5 +1,6 @@ /* (C) 2013 by Andreas Eversberg * (C) 2015 by Alexander Chemeris + * (C) 2016 by Tom Tsou * * All Rights Reserved * @@ -27,7 +28,10 @@ #include #include #include +#include #include +#include +#include #include #include @@ -39,24 +43,427 @@ #include "gsm0503_tables.h" #include "gsm0503_coding.h" +/* + * 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 + +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_conv_mcs1_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs1_ul_hdr, + + .data_len = 178, + .data_code_len = 588, + .data_punc_len = 372, + .data_conv = &gsm0503_conv_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_conv_mcs1_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs1_ul_hdr, + + .data_len = 226, + .data_code_len = 732, + .data_punc_len = 372, + .data_conv = &gsm0503_conv_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_conv_mcs1_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs1_ul_hdr, + + .data_len = 298, + .data_code_len = 948, + .data_punc_len = 372, + .data_conv = &gsm0503_conv_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_conv_mcs1_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs1_ul_hdr, + + .data_len = 354, + .data_code_len = 1116, + .data_punc_len = 372, + .data_conv = &gsm0503_conv_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_conv_mcs5_ul_hdr, + .hdr_punc = NULL, + + .data_len = 450, + .data_code_len = 1404, + .data_punc_len = 1248, + .data_conv = &gsm0503_conv_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_conv_mcs5_ul_hdr, + .hdr_punc = NULL, + + .data_len = 594, + .data_code_len = 1836, + .data_punc_len = 1248, + .data_conv = &gsm0503_conv_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_conv_mcs7_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs7_ul_hdr, + .hdr_len = 46, + + .data_len = 900, + .data_code_len = 1404, + .data_punc_len = 612, + .data_conv = &gsm0503_conv_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_conv_mcs7_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs7_ul_hdr, + .hdr_len = 46, + + .data_len = 1092, + .data_code_len = 1692, + .data_punc_len = 612, + .data_conv = &gsm0503_conv_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_conv_mcs7_ul_hdr, + .hdr_punc = gsm0503_puncture_mcs7_ul_hdr, + .hdr_len = 46, + + .data_len = 1188, + .data_code_len = 1836, + .data_punc_len = 612, + .data_conv = &gsm0503_conv_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_conv_mcs1_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs1_dl_hdr, + + .data_len = 178, + .data_code_len = 588, + .data_punc_len = 372, + .data_conv = &gsm0503_conv_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_conv_mcs1_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs1_dl_hdr, + + .data_len = 226, + .data_code_len = 732, + .data_punc_len = 372, + .data_conv = &gsm0503_conv_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_conv_mcs1_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs1_dl_hdr, + + .data_len = 298, + .data_code_len = 948, + .data_punc_len = 372, + .data_conv = &gsm0503_conv_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_conv_mcs1_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs1_dl_hdr, + + .data_len = 354, + .data_code_len = 1116, + .data_punc_len = 372, + .data_conv = &gsm0503_conv_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_conv_mcs5_dl_hdr, + .hdr_punc = NULL, + + .data_len = 450, + .data_code_len = 1404, + .data_punc_len = 1248, + .data_conv = &gsm0503_conv_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_conv_mcs5_dl_hdr, + .hdr_punc = NULL, + + .data_len = 594, + .data_code_len = 1836, + .data_punc_len = 1248, + .data_conv = &gsm0503_conv_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_conv_mcs7_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs7_dl_hdr, + + .data_len = 900, + .data_code_len = 1404, + .data_punc_len = 612, + .data_conv = &gsm0503_conv_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_conv_mcs7_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs7_dl_hdr, + + .data_len = 1092, + .data_code_len = 1692, + .data_punc_len = 612, + .data_conv = &gsm0503_conv_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_conv_mcs7_dl_hdr, + .hdr_punc = gsm0503_puncture_mcs7_dl_hdr, + + .data_len = 1188, + .data_code_len = 1836, + .data_punc_len = 612, + .data_conv = &gsm0503_conv_mcs9, + .data_punc = { + gsm0503_puncture_mcs9_p1, + gsm0503_puncture_mcs9_p2, + gsm0503_puncture_mcs9_p3, + } + }, +}; + 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; - ubit_t recoded[1024]; /* TODO: We can do smaller, I guess */ + ubit_t recoded[EGPRS_DATA_C_MAX]; res = osmo_conv_decode(code, input, output); - *n_bits_total = osmo_conv_encode(code, output, recoded); - OSMO_ASSERT(sizeof(recoded)/sizeof(recoded[0]) >= *n_bits_total); + if (n_bits_total) { + *n_bits_total = osmo_conv_encode(code, output, recoded); + OSMO_ASSERT(sizeof(recoded)/sizeof(recoded[0]) >= *n_bits_total); + } /* Count bit errors */ - *n_errors = 0; - for (i=0; i< *n_bits_total; i++) { - if (! ((recoded[i] && input[i]<0) || - (!recoded[i] && input[i]>0)) ) - *n_errors += 1; + if (n_errors) { + *n_errors = 0; + for (i=0; i< *n_bits_total; i++) { + if (! ((recoded[i] && input[i]<0) || + (!recoded[i] && input[i]>0)) ) + *n_errors += 1; + } } return res; @@ -129,6 +536,335 @@ int xcch_encode(ubit_t *bursts, uint8_t *l2_data) 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; +} + +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; +}; + +/* + * 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) { + LOGP(DL1C, LOGL_ERROR, + "Invalid MCS-%u header puncture matrix\n", mcs); + 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 indentification. 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); +} + +#define NUM_BYTES(N) ((N + 8 - 1) / 8) + +/* + * 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) { + LOGP(DL1C, LOGL_ERROR, "Invalid MCS-%u block state\n", mcs); + return -1; + } + + code = &gsm0503_mcs_ul_codes[mcs]; + if (!code->data_punc[p]) { + LOGP(DL1C, LOGL_ERROR, + "Invalid MCS-%u data puncture matrix %i\n", mcs, p); + 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 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)) { + LOGP(DL1C, LOGL_ERROR, "Invalid EGPRS bit length %u\n", nbits); + 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: + LOGP(DL1C, LOGL_ERROR, "Invalid MCS-%u\n", cps.mcs); + return -1; + } + + LOGP(DL1C, LOGL_DEBUG, "Decoding MCS-%i block\n", 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 @@ -278,6 +1014,268 @@ int pdtch_decode(uint8_t *l2_data, sbit_t *bursts, uint8_t *usf_p, 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) { + LOGP(DL1C, LOGL_ERROR, + "Invalid MCS-%u header puncture matrix\n", mcs); + 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]) { + LOGP(DL1C, LOGL_ERROR, + "Invalid MCS-%u data puncture matrix %i\n", mcs, p); + 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; +} + +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; +}; + +/* + * 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 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; + } + + LOGP(DL1C, LOGL_DEBUG, "Encoded PDTCH mcs=%i, len=%u\n", mcs, l2_len); + + return mcs >= EGPRS_MCS5 ? GSM0503_EGPRS_BURSTS_NBITS : + GSM0503_GPRS_BURSTS_NBITS; + +bad_header: + LOGP(DL1C, LOGL_ERROR, "Invalid EGPRS MCS-%i header\n", mcs); + return -1; +} + int pdtch_encode(ubit_t *bursts, uint8_t *l2_data, uint8_t l2_len) { ubit_t iB[456], cB[676]; diff --git a/src/osmo-bts-trx/gsm0503_coding.h b/src/osmo-bts-trx/gsm0503_coding.h index a454d8f4..cdee13be 100644 --- a/src/osmo-bts-trx/gsm0503_coding.h +++ b/src/osmo-bts-trx/gsm0503_coding.h @@ -21,12 +21,34 @@ #ifndef _0503_CODING_H #define _0503_CODING_H +#define GSM0503_GPRS_BURSTS_NBITS (116 * 4) +#define GSM0503_EGPRS_BURSTS_NBITS (348 * 4) + +struct osmo_conv_code; + +enum egprs_mcs { + EGPRS_MCS0, + EGPRS_MCS1, + EGPRS_MCS2, + EGPRS_MCS3, + EGPRS_MCS4, + EGPRS_MCS5, + EGPRS_MCS6, + EGPRS_MCS7, + EGPRS_MCS8, + EGPRS_MCS9, + EGPRS_NUM_MCS, +}; + int xcch_decode(uint8_t *l2_data, sbit_t *bursts, int *n_errors, int *n_bits_total); int xcch_encode(ubit_t *bursts, uint8_t *l2_data); int pdtch_decode(uint8_t *l2_data, sbit_t *bursts, uint8_t *usf_p, int *n_errors, int *n_bits_total); +int pdtch_egprs_decode(uint8_t *l2_data, sbit_t *bursts, uint16_t nbits, + uint8_t *usf_p, int *n_errors, int *n_bits_total); int pdtch_encode(ubit_t *bursts, uint8_t *l2_data, uint8_t l2_len); +int pdtch_egprs_encode(ubit_t *bursts, uint8_t *l2_data, uint8_t l2_len); int tch_fr_decode(uint8_t *tch_data, sbit_t *bursts, int net_order, int efr, int *n_errors, int *n_bits_total); int tch_fr_encode(ubit_t *bursts, uint8_t *tch_data, int len, int net_order); -- cgit v1.2.3