/* * (C) 2013 by Andreas Eversberg * (C) 2015-2017 by Harald Welte * (C) 2020-2023 by sysmocom - s.f.m.c. GmbH * * All Rights Reserved * * This program 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. * * 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 Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see . * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* 3GPP TS 45.009, table 3.2.1.3-{2,4}: AMR on Uplink TCH/H. * * +---+---+---+---+---+---+ * | a | b | c | d | e | f | Burst 'a' received first * +---+---+---+---+---+---+ * ^^^^^^^^^^^^^^^^^^^^^^^ FACCH frame (bursts 'a' .. 'f') * ^^^^^^^^^^^^^^^ Speech frame (bursts 'a' .. 'd') * * TDMA frame number of burst 'f' is always used as the table index. */ static const uint8_t sched_tchh_ul_amr_cmi_map[26] = { [10] = 1, /* TCH/H(0): a=0 / d=6 / f=10 */ [19] = 1, /* TCH/H(0): a=8 / d=15 / f=19 */ [2] = 1, /* TCH/H(0): a=17 / d=23 / f=2 */ [11] = 1, /* TCH/H(1): a=1 / d=7 / f=11 */ [20] = 1, /* TCH/H(1): a=9 / d=16 / f=20 */ [3] = 1, /* TCH/H(1): a=18 / d=24 / f=3 */ }; /* TDMA frame number of burst 'a' should be used as the table index. * This mapping is valid for both FACCH/H(0) and FACCH/H(1). */ const uint8_t sched_tchh_dl_amr_cmi_map[26] = { [4] = 1, /* TCH/H(0): a=4 */ [13] = 1, /* TCH/H(0): a=13 */ [21] = 1, /* TCH/H(0): a=21 */ [5] = 1, /* TCH/H(1): a=5 */ [14] = 1, /* TCH/H(1): a=14 */ [22] = 1, /* TCH/H(1): a=22 */ }; /* 3GPP TS 45.002, table 1 in clause 7: Mapping tables. * TDMA frame number of burst 'f' is always used as the table index. */ static const uint8_t sched_tchh_ul_facch_map[26] = { [10] = 1, /* FACCH/H(0): B0(0,2,4,6,8,10) */ [11] = 1, /* FACCH/H(1): B0(1,3,5,7,9,11) */ [19] = 1, /* FACCH/H(0): B1(8,10,13,15,17,19) */ [20] = 1, /* FACCH/H(1): B1(9,11,14,16,18,20) */ [2] = 1, /* FACCH/H(0): B2(17,19,21,23,0,2) */ [3] = 1, /* FACCH/H(1): B2(18,20,22,24,1,3) */ }; /* TDMA frame number of burst 'a' is used as the table index. */ extern const uint8_t sched_tchh_dl_facch_map[26]; /* 3GPP TS 45.002, table 2 in clause 7: Mapping tables for TCH/H2.4 and TCH/H4.8. * * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ * | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ * * TCH/H(0): B0(0,2,4,6,8,10,13,15,17,19,21,23,0,2,4,6,8,10,13,15,17,19) * TCH/H(1): B0(1,3,5,7,9,11,14,16,18,20,22,24,1,3,5,7,9,11,14,16,18,20) * TCH/H(0): B1(8,10,13,15,17,19,21,23,0,2,4,6,8,10,13,15,17,19,21,23,0,2) * TCH/H(1): B1(9,11,14,16,18,20,22,24,1,3,5,7,9,11,14,16,18,20,22,24,1,3) * TCH/H(0): B2(17,19,21,23,0,2,4,6,8,10,13,15,17,19,21,23,0,2,4,6,8,10) * TCH/H(1): B2(18,20,22,24,1,3,5,7,9,11,14,16,18,20,22,24,1,3,5,7,9,11) * * TDMA frame number of burst 'v' % 26 is the table index. * This mapping is valid for both TCH/H(0) and TCH/H(1). */ static const uint8_t sched_tchh_ul_csd_map[26] = { [19] = 1, /* TCH/H(0): B0(0 ... 19) */ [20] = 1, /* TCH/H(1): B0(1 ... 20) */ [2] = 1, /* TCH/H(0): B1(8 ... 2) */ [3] = 1, /* TCH/H(1): B1(9 ... 3) */ [10] = 1, /* TCH/H(0): B2(17 ... 10) */ [11] = 1, /* TCH/H(1): B2(18 ... 11) */ }; /* TDMA frame number of burst 'a' % 26 is the table index. * This mapping is valid for both TCH/H(0) and TCH/H(1). */ extern const uint8_t sched_tchh_dl_csd_map[26]; static int decode_hr_facch(struct l1sched_ts *l1ts, const struct trx_ul_burst_ind *bi) { struct l1sched_chan_state *chan_state = &l1ts->chan_state[bi->chan]; const sbit_t *bursts_p = chan_state->ul_bursts; struct l1sched_meas_set meas_avg; uint8_t data[GSM_MACBLOCK_LEN]; int n_errors, n_bits_total; int rc; rc = gsm0503_tch_hr_facch_decode(&data[0], BUFTAIL8(bursts_p), &n_errors, &n_bits_total); if (rc != GSM_MACBLOCK_LEN) return rc; /* average measurements of the last 6 bursts, obtain TDMA Fn of the first burst */ trx_sched_meas_avg(chan_state, &meas_avg, SCHED_MEAS_AVG_M_S6N6); _sched_compose_ph_data_ind(l1ts, meas_avg.fn, bi->chan, &data[0], GSM_MACBLOCK_LEN, compute_ber10k(n_bits_total, n_errors), meas_avg.rssi, meas_avg.toa256, meas_avg.ci_cb, PRES_INFO_UNKNOWN); return GSM_MACBLOCK_LEN; } /* Process a single Uplink TCH/H burst received by the PHY. * This function is visualized in file 'doc/trx_sched_tch.txt'. */ int rx_tchh_fn(struct l1sched_ts *l1ts, const struct trx_ul_burst_ind *bi) { struct l1sched_chan_state *chan_state = &l1ts->chan_state[bi->chan]; struct gsm_lchan *lchan = chan_state->lchan; sbit_t *burst, *bursts_p = chan_state->ul_bursts; uint32_t *mask = &chan_state->ul_mask; uint8_t rsl_cmode = chan_state->rsl_cmode; uint8_t tch_mode = chan_state->tch_mode; uint8_t tch_data[240]; /* large enough to hold 240 unpacked bits for CSD */ int rc = 0; /* initialize to make gcc happy */ int amr = 0; int n_errors = 0; int n_bits_total = 0; enum sched_meas_avg_mode meas_avg_mode = SCHED_MEAS_AVG_M_S6N4; struct l1sched_meas_set meas_avg; unsigned int fn_begin; uint16_t ber10k = 0; uint8_t is_sub = 0; uint8_t ft; bool fn_is_cmi; /* If handover RACH detection is turned on, treat this burst as an Access Burst. * Handle NOPE.ind as usually to ensure proper Uplink measurement reporting. */ if (chan_state->ho_rach_detect == 1 && ~bi->flags & TRX_BI_F_NOPE_IND) return rx_rach_fn(l1ts, bi); LOGL1SB(DL1P, LOGL_DEBUG, l1ts, bi, "Received TCH/H, bid=%u\n", bi->bid); /* shift the buffer by 2 bursts leftwards */ if (bi->bid == 0) { memmove(BUFPOS(bursts_p, 0), BUFPOS(bursts_p, 2), 20 * BPLEN); memset(BUFPOS(bursts_p, 20), 0, 2 * BPLEN); *mask = *mask << 2; } /* update mask */ *mask |= (1 << bi->bid); /* store measurements */ trx_sched_meas_push(chan_state, bi); /* copy burst to end of buffer of 24 bursts */ burst = BUFPOS(bursts_p, 20 + bi->bid); if (bi->burst_len > 0) { memcpy(burst, bi->burst + 3, 58); memcpy(burst + 58, bi->burst + 87, 58); } /* wait until complete set of bursts */ if (bi->bid != 1) return 0; /* fill up the burst buffer so that we have 6 bursts in there */ if (OSMO_UNLIKELY((*mask & 0x3f) != 0x3f)) { LOGL1SB(DL1P, LOGL_DEBUG, l1ts, bi, "UL burst buffer is not filled up: mask=0x%02x != 0x3f\n", *mask); return 0; /* TODO: send BFI */ } /* skip decoding of the last 4 bursts of FACCH/H */ if (chan_state->ul_ongoing_facch) { chan_state->ul_ongoing_facch = 0; /* we have already sent the first BFI when a FACCH/H frame * was decoded (see below), now send the second one. */ trx_sched_meas_avg(chan_state, &meas_avg, meas_avg_mode); /* meas_avg.fn now contains TDMA frame number of the first burst */ fn_begin = meas_avg.fn; goto bfi; } /* TCH/H: speech and signalling frames are interleaved over 4 and 6 bursts, * respectively, while CSD frames are interleaved over 22 bursts. Unless * we're in CSD mode, decode only the last 6 bursts to avoid introducing * additional delays. */ switch (tch_mode) { case GSM48_CMODE_SIGN: meas_avg_mode = SCHED_MEAS_AVG_M_S6N6; /* fall-through */ case GSM48_CMODE_SPEECH_V1: /* HR or signalling */ rc = gsm0503_tch_hr_decode2(tch_data, BUFTAIL8(bursts_p), !sched_tchh_ul_facch_map[bi->fn % 26], &n_errors, &n_bits_total); if (rc == GSM_HR_BYTES) { /* only for valid *speech* frames */ bool is_sid = osmo_hr_check_sid(tch_data, GSM_HR_BYTES); lchan_set_marker(is_sid, lchan); /* DTXu */ } break; case GSM48_CMODE_SPEECH_AMR: /* AMR */ /* the first FN 0,8,17 or 1,9,18 defines that CMI is included * in frame, the first FN 4,13,21 or 5,14,22 defines that CMR * is included in frame. */ /* See comment in function rx_tchf_fn() */ switch (chan_state->amr_last_dtx) { case AHS_ONSET: case AHS_SID_FIRST_INH: case AHS_SID_UPDATE_INH: lchan_set_marker(false, lchan); break; } fn_is_cmi = sched_tchh_ul_amr_cmi_map[bi->fn % 26]; /* See comment in function rx_tchf_fn() */ amr = sizeof(struct amr_hdr); rc = gsm0503_tch_ahs_decode_dtx(tch_data + amr, BUFTAIL8(bursts_p), !sched_tchh_ul_facch_map[bi->fn % 26], !fn_is_cmi, chan_state->codec, chan_state->codecs, &chan_state->ul_ft, &chan_state->ul_cmr, &n_errors, &n_bits_total, &chan_state->amr_last_dtx); /* Tag all frames that are not regular AMR voice frames as SUB-Frames */ if (chan_state->amr_last_dtx != AMR_OTHER) { LOGL1SB(DL1P, LOGL_DEBUG, l1ts, bi, "Received AMR DTX frame (rc=%d, BER %d/%d): %s\n", rc, n_errors, n_bits_total, gsm0503_amr_dtx_frame_name(chan_state->amr_last_dtx)); is_sub = 1; } /* See comment in function rx_tchf_fn() */ switch (chan_state->amr_last_dtx) { case AHS_SID_FIRST_P1: case AHS_SID_FIRST_P2: case AHS_SID_UPDATE: case AHS_SID_UPDATE_CN: lchan_set_marker(true, lchan); lchan->rtp_tx_marker = false; break; } switch (chan_state->amr_last_dtx) { case AHS_SID_FIRST_P1: case AHS_SID_FIRST_P2: case AHS_SID_UPDATE: case AHS_SID_UPDATE_CN: case AHS_SID_FIRST_INH: case AHS_SID_UPDATE_INH: meas_avg_mode = SCHED_MEAS_AVG_M_S6N2; break; case AHS_ONSET: meas_avg_mode = SCHED_MEAS_AVG_M_S4N2; break; } /* only good speech frames get rtp header */ if (rc != GSM_MACBLOCK_LEN && rc >= 4) { if (chan_state->amr_last_dtx == AMR_OTHER) { ft = chan_state->codec[chan_state->ul_ft]; } else { /* SID frames will always get Frame Type Index 8 (AMR_SID) */ ft = AMR_SID; } rc = osmo_amr_rtp_enc(tch_data, chan_state->codec[chan_state->ul_cmr], ft, AMR_GOOD); } break; /* CSD (TCH/H4.8): 6.0 kbit/s radio interface rate */ case GSM48_CMODE_DATA_6k0: if (!sched_tchh_ul_csd_map[bi->fn % 26]) return 0; /* CSD: skip decoding attempt, need 2 more bursts */ /* FACCH/H does not steal TCH/H4.8 frames, but only disturbs some bits */ decode_hr_facch(l1ts, bi); rc = gsm0503_tch_hr48_decode(&tch_data[0], BUFPOS(bursts_p, 0), &n_errors, &n_bits_total); meas_avg_mode = SCHED_MEAS_AVG_M_S22N22; break; /* CSD (TCH/H2.4): 3.6 kbit/s radio interface rate */ case GSM48_CMODE_DATA_3k6: if (!sched_tchh_ul_csd_map[bi->fn % 26]) return 0; /* CSD: skip decoding attempt, need 2 more bursts */ /* FACCH/H does not steal TCH/H2.4 frames, but only disturbs some bits */ decode_hr_facch(l1ts, bi); rc = gsm0503_tch_hr24_decode(&tch_data[0], BUFPOS(bursts_p, 0), &n_errors, &n_bits_total); meas_avg_mode = SCHED_MEAS_AVG_M_S22N22; break; default: LOGL1SB(DL1P, LOGL_ERROR, l1ts, bi, "TCH mode %u invalid, please fix!\n", tch_mode); return -EINVAL; } ber10k = compute_ber10k(n_bits_total, n_errors); /* average measurements of the last N (depends on mode) bursts */ trx_sched_meas_avg(chan_state, &meas_avg, meas_avg_mode); /* meas_avg.fn now contains TDMA frame number of the first burst */ fn_begin = meas_avg.fn; if (tch_mode == GSM48_CMODE_SPEECH_AMR) trx_loop_amr_input(chan_state, &meas_avg); /* Check if the frame is bad */ if (rc < 4) { LOGL1SB(DL1P, LOGL_NOTICE, l1ts, bi, BAD_DATA_MSG_FMT "\n", BAD_DATA_MSG_ARGS); rc = 0; /* this is how we signal BFI to l1sap */ } else if (rc == GSM_MACBLOCK_LEN) { /* FACCH */ chan_state->ul_ongoing_facch = 1; /* In order to provide an even stream of measurement reports in *speech* * mode, here we intentionally invalidate RSSI for FACCH, so that this * report gets dropped in process_l1sap_meas_data(). The averaged results * will be sent with the first (see below) and second (see above) BFIs. */ _sched_compose_ph_data_ind(l1ts, fn_begin, bi->chan, &tch_data[amr], GSM_MACBLOCK_LEN, ber10k, tch_mode == GSM48_CMODE_SIGN ? meas_avg.rssi : 0, meas_avg.toa256, meas_avg.ci_cb, PRES_INFO_UNKNOWN); ber10k = 0; bfi: /* A FACCH/H frame replaces two speech frames, so we need to send two BFIs. * One is sent here, another will be sent two bursts later (see above). */ rc = 0; } if (rsl_cmode == RSL_CMOD_SPD_SIGN) return 0; /* TCH or BFI */ return _sched_compose_tch_ind(l1ts, fn_begin, bi->chan, &tch_data[0], rc, ber10k, meas_avg.rssi, meas_avg.toa256, meas_avg.ci_cb, is_sub); } /* common section for generation of TCH bursts (TCH/H and TCH/F). * FIXME: this function is over-complicated, refactor / get rid of it. */ extern void tch_dl_dequeue(struct l1sched_ts *l1ts, const struct trx_dl_burst_req *br, struct msgb **msg_tch, struct msgb **msg_facch); struct msgb *tch_dummy_msgb(size_t size, uint8_t pad); /* obtain a to-be-transmitted TCH/H (Half Traffic Channel) burst */ int tx_tchh_fn(struct l1sched_ts *l1ts, struct trx_dl_burst_req *br) { struct l1sched_chan_state *chan_state = &l1ts->chan_state[br->chan]; uint8_t tch_mode = chan_state->tch_mode; ubit_t *burst, *bursts_p = chan_state->dl_bursts; uint8_t *mask = &chan_state->dl_mask; struct msgb *msg_facch = NULL; struct msgb *msg_tch = NULL; struct msgb *msg = NULL; /* send burst, if we already got a frame */ if (br->bid > 0) { if ((*mask & 0x01) != 0x01) return -ENOMSG; goto send_burst; } *mask = *mask << 2; /* BURST BYPASS */ /* shift buffer by 2 bursts for interleaving */ memmove(BUFPOS(bursts_p, 0), BUFPOS(bursts_p, 2), 20 * BPLEN); memset(BUFPOS(bursts_p, 20), 0, 2 * BPLEN); /* dequeue a TCH and/or a FACCH message to be transmitted */ tch_dl_dequeue(l1ts, br, &msg_tch, &msg_facch); /* if we're sending 2 middle bursts of FACCH/H */ if (chan_state->dl_ongoing_facch) { /* FACCH/H shall not be scheduled at wrong FNs */ OSMO_ASSERT(msg_facch == NULL); msgb_free(msg_tch); /* drop 2nd speech frame */ chan_state->dl_ongoing_facch = 0; goto send_burst; } /* no message at all, send a dummy L2 frame on FACCH */ if (msg_tch == NULL && msg_facch == NULL) { int rc; LOGL1SB(DL1P, LOGL_INFO, l1ts, br, "No TCH or FACCH prim for transmit.\n"); /* - If the channel mode is TCH/HS, transmit a dummy speech block * with inverted CRC3, designed to induce a BFI condition in * the MS receiver. * - If the channel mode is TCH/AHS, transmit a dummy speech * block with inverted CRC6, designed to induce a BFI * condition in the MS receiver. * - If the channel mode is one of the CSD modes, transmit an * idle frame as described in 3GPP TS 44.021, sections 8.1.6 * and 10.2.3 (all data, status and E-bits set to binary '1'). * - In all other channel modes, transmit dummy FACCH * like we always did before. */ switch (tch_mode) { case GSM48_CMODE_DATA_6k0: case GSM48_CMODE_DATA_3k6: break; /* see below */ case GSM48_CMODE_SPEECH_V1: rc = gsm0503_tch_hr_encode(BUFPOS(bursts_p, 0), NULL, 0); if (rc == 0) goto send_burst; /* fall-through */ case GSM48_CMODE_SIGN: default: if (tch_mode == GSM48_CMODE_SPEECH_AMR) { /* the first FN 4,13,21 or 5,14,22 defines that CMI is included * in frame, the first FN 0,8,17 or 1,9,18 defines that CMR is * included in frame. */ rc = gsm0503_tch_ahs_encode(BUFPOS(bursts_p, 0), NULL, 0, !sched_tchh_dl_amr_cmi_map[br->fn % 26], chan_state->codec, chan_state->codecs, chan_state->dl_ft, chan_state->dl_cmr); if (rc == 0) goto send_burst; } /* FACCH/H can only be scheduled at specific TDMA offset */ if (!sched_tchh_dl_facch_map[br->fn % 26]) { /* FACCH/H is not allowed, send half-filled bursts with even numbered * bits contaning 232 encoded bits of the previous L2 frame, and 232 * odd numbered bits all set to 0. */ goto send_burst; } /* TODO: use randomized padding */ msg_facch = tch_dummy_msgb(GSM_MACBLOCK_LEN, GSM_MACBLOCK_PADDING); /* dummy LAPDm func=UI frame */ msg_facch->l2h[0] = 0x03; msg_facch->l2h[1] = 0x03; msg_facch->l2h[2] = 0x01; break; } } /* Unlike SACCH, FACCH has no dedicated slots on the multiframe layout. * It's multiplexed together with TCH (speech or data) frames basically * by replacing (stealing) their bits, either completely or partly. */ msg = (msg_facch != NULL) ? msg_facch : msg_tch; if (msg == msg_facch) { if (chan_state->rsl_cmode != RSL_CMOD_SPD_DATA) chan_state->dl_ongoing_facch = 1; chan_state->dl_facch_bursts = 6; } /* populate the buffer with bursts */ switch (tch_mode) { case GSM48_CMODE_SIGN: case GSM48_CMODE_SPEECH_V1: gsm0503_tch_hr_encode(BUFPOS(bursts_p, 0), msg->l2h, msgb_l2len(msg)); break; case GSM48_CMODE_SPEECH_AMR: /* the first FN 4,13,21 or 5,14,22 defines that CMI is included * in frame, the first FN 0,8,17 or 1,9,18 defines that CMR is * included in frame. */ gsm0503_tch_ahs_encode(BUFPOS(bursts_p, 0), msgb_l2(msg), msgb_l2len(msg), !sched_tchh_dl_amr_cmi_map[br->fn % 26], chan_state->codec, chan_state->codecs, chan_state->dl_ft, chan_state->dl_cmr); break; /* CSD (TCH/H4.8): 6.0 kbit/s radio interface rate */ case GSM48_CMODE_DATA_6k0: /* for half-rate CSD we run the encoder every 4th burst (like for TCH/F) * because the interleaving is done as specified for the TCH/F9.6 */ if (sched_tchh_dl_csd_map[br->fn % 26]) { if (msg_tch == NULL) msg_tch = tch_dummy_msgb(4 * 60, 0x01); gsm0503_tch_hr48_encode(BUFPOS(bursts_p, 0), msgb_l2(msg_tch)); } if (msg_facch != NULL) gsm0503_tch_hr_facch_encode(BUFPOS(bursts_p, 0), msgb_l2(msg_facch)); break; /* CSD (TCH/H2.4): 3.6 kbit/s radio interface rate */ case GSM48_CMODE_DATA_3k6: /* for half-rate CSD we run the encoder every 4th burst (like for TCH/F) * because the interleaving is done as specified for the TCH/F9.6 */ if (sched_tchh_dl_csd_map[br->fn % 26]) { if (msg_tch == NULL) msg_tch = tch_dummy_msgb(4 * 36, 0x01); gsm0503_tch_hr24_encode(BUFPOS(bursts_p, 0), msgb_l2(msg_tch)); } if (msg_facch != NULL) gsm0503_tch_hr_facch_encode(BUFPOS(bursts_p, 0), msgb_l2(msg_facch)); break; default: OSMO_ASSERT(0); } /* free messages */ msgb_free(msg_tch); msgb_free(msg_facch); send_burst: /* compose burst */ burst = BUFPOS(bursts_p, br->bid); memcpy(br->burst + 3, burst, 58); memcpy(br->burst + 61, TRX_GMSK_NB_TSC(br), 26); memcpy(br->burst + 87, burst + 58, 58); br->burst_len = GSM_BURST_LEN; if (chan_state->dl_facch_bursts > 0) { chan_state->dl_facch_bursts--; br->flags |= TRX_BR_F_FACCH; } *mask |= (1 << br->bid); LOGL1SB(DL1P, LOGL_DEBUG, l1ts, br, "Transmitting burst=%u.\n", br->bid); return 0; }