diff options
| -rw-r--r-- | include/osmo-bts/scheduler.h | 14 | ||||
| -rw-r--r-- | src/osmo-bts-trx/trx_if.c | 170 |
2 files changed, 183 insertions, 1 deletions
diff --git a/include/osmo-bts/scheduler.h b/include/osmo-bts/scheduler.h index 9748d45c..4f406360 100644 --- a/include/osmo-bts/scheduler.h +++ b/include/osmo-bts/scheduler.h @@ -227,14 +227,28 @@ int find_sched_mframe_idx(enum gsm_phys_chan_config pchan, uint8_t tn); bool trx_sched_is_sacch_fn(struct gsm_bts_trx_ts *ts, uint32_t fn, bool uplink); extern const struct trx_sched_multiframe trx_sched_multiframes[]; +#define TRX_BI_F_NOPE_IND (1 << 0) +#define TRX_BI_F_MOD_TYPE (1 << 1) +#define TRX_BI_F_TS_INFO (1 << 2) +#define TRX_BI_F_CI_CB (1 << 3) + /*! UL burst indication with the corresponding meta info */ struct trx_ul_burst_ind { + /* Field presence bitmask (see TRX_BI_F_*) */ + uint8_t flags; + /* Mandatory fields */ uint32_t fn; /*!< TDMA frame number */ uint8_t tn; /*!< TDMA time-slot number */ int16_t toa256; /*!< Timing of Arrival in units of 1/256 of symbol */ int8_t rssi; /*!< Received Signal Strength Indication */ + /* Optional fields (defined by flags) */ + enum trx_burst_type bt; /*!< Modulation type */ + uint8_t tsc_set; /*!< Training Sequence Set */ + uint8_t tsc; /*!< Training Sequence Code */ + int16_t ci_cb; /*!< Carrier-to-Interference ratio (in centiBels) */ + /*! Burst soft-bits buffer */ sbit_t burst[EGPRS_BURST_LEN]; size_t burst_len; diff --git a/src/osmo-bts-trx/trx_if.c b/src/osmo-bts-trx/trx_if.c index a164f173..f2e8b906 100644 --- a/src/osmo-bts-trx/trx_if.c +++ b/src/osmo-bts-trx/trx_if.c @@ -593,6 +593,8 @@ rsp_error: #define TRX_CHDR_LEN (1 + 4) /* Uplink v0 header length: 1 RSSI + 2 ToA256 */ #define TRX_UL_V0HDR_LEN (TRX_CHDR_LEN + 1 + 2) +/* Uplink v1 header length: + 1 MTS + 2 C/I */ +#define TRX_UL_V1HDR_LEN (TRX_UL_V0HDR_LEN + 1 + 2) /* TRXD header dissector for version 0 */ static int trx_data_handle_hdr_v0(struct trx_l1h *l1h, @@ -621,6 +623,64 @@ static int trx_data_handle_hdr_v0(struct trx_l1h *l1h, return TRX_UL_V0HDR_LEN; } +/* TRXD header dissector for version 0x01 */ +static int trx_data_handle_hdr_v1(struct trx_l1h *l1h, + struct trx_ul_burst_ind *bi, + const uint8_t *buf, size_t buf_len) +{ + uint8_t mts; + int rc; + + /* Make sure we have enough data */ + if (buf_len < TRX_UL_V1HDR_LEN) { + LOGPPHI(l1h->phy_inst, DTRX, LOGL_ERROR, + "Short read on TRXD, missing version 1 header " + "(len=%zu vs expected %d)\n", buf_len, TRX_UL_V1HDR_LEN); + return -EIO; + } + + /* Parse v0 specific part */ + rc = trx_data_handle_hdr_v0(l1h, bi, buf, buf_len); + if (rc < 0) + return rc; + + /* Move closer to the v1 specific part */ + buf_len -= rc; + buf += rc; + + /* IDLE / NOPE frame indication */ + if (buf[0] & (1 << 7)) { + bi->flags |= TRX_BI_F_NOPE_IND; + return TRX_UL_V1HDR_LEN; + } + + /* Modulation info and TSC set */ + mts = (buf[0] >> 3) & 0b1111; + if ((mts & 0b1100) == 0x00) { + bi->bt = TRX_BURST_GMSK; + bi->tsc_set = mts & 0b11; + bi->flags |= TRX_BI_F_MOD_TYPE; + } else if ((mts & 0b0100) == 0b0100) { + bi->bt = TRX_BURST_8PSK; + bi->tsc_set = mts & 0b1; + bi->flags |= TRX_BI_F_MOD_TYPE; + } else { + LOGPPHI(l1h->phy_inst, DTRX, LOGL_ERROR, + "Indicated modulation 0x%02x is not supported\n", mts & 0b1110); + return -ENOTSUP; + } + + /* Training Sequence Code */ + bi->tsc = buf[0] & 0b111; + bi->flags |= TRX_BI_F_TS_INFO; + + /* C/I: Carrier-to-Interference ratio (in centiBels) */ + bi->ci_cb = (int16_t) osmo_load16be(buf + 1); + bi->flags |= TRX_BI_F_CI_CB; + + return TRX_UL_V1HDR_LEN; +} + /* TRXD burst handler for header version 0 */ static int trx_data_handle_burst_v0(struct trx_l1h *l1h, struct trx_ul_burst_ind *bi, @@ -657,6 +717,30 @@ static int trx_data_handle_burst_v0(struct trx_l1h *l1h, return 0; } +/* TRXD burst handler for header version 1 */ +static int trx_data_handle_burst_v1(struct trx_l1h *l1h, + struct trx_ul_burst_ind *bi, + const uint8_t *buf, size_t buf_len) +{ + /* Modulation types defined in 3GPP TS 45.002 */ + static const size_t bl[] = { + [TRX_BURST_GMSK] = 148, /* 1 bit per symbol */ + [TRX_BURST_8PSK] = 444, /* 3 bits per symbol */ + }; + + /* Verify burst length */ + if (bl[bi->bt] != buf_len) { + LOGPPHI(l1h->phy_inst, DTRX, LOGL_NOTICE, + "Rx TRXD message with odd burst length %zu, " + "expected %zu\n", buf_len, bl[bi->bt]); + return -EINVAL; + } + + /* The burst format is the same as for version 0. + * NOTE: other modulation types to be handled separately. */ + return trx_data_handle_burst_v0(l1h, bi, buf, buf_len); +} + /* Parse TRXD message from transceiver, compose an UL burst indication. * * This message contains a demodulated Uplink burst with fixed-size @@ -697,12 +781,72 @@ static int trx_data_handle_burst_v0(struct trx_l1h *l1h, * | RSSI | ToA | soft-bits (254..0) | * +------+-----+--------------------+ * + * == Version 0x01 + * + * +------+-----+-----+-----+--------------------+ + * | RSSI | ToA | MTS | C/I | soft-bits (254..0) | + * +------+-----+-----+-----+--------------------+ + * * where: * * - RSSI (1 octet) - Received Signal Strength Indication * encoded without the negative sign. * - ToA (2 octets) - Timing of Arrival in units of 1/256 * of symbol (big endian). + * - MTS (1 octet) - Modulation and Training Sequence info. + * - C/I (2 octets) - Carrier-to-Interference ratio (big endian). + * + * == Coding of MTS: Modulation and Training Sequence info + * + * 3GPP TS 45.002 version 15.1.0 defines several modulation types, + * and a few sets of training sequences for each type. The most + * common are GMSK and 8-PSK (which is used in EDGE). + * + * +-----------------+---------------------------------------+ + * | 7 6 5 4 3 2 1 0 | bit numbers (value range) | + * +-----------------+---------------------------------------+ + * | . . . . . X X X | Training Sequence Code (0..7) | + * +-----------------+---------------------------------------+ + * | . X X X X . . . | Modulation, TS set number (see below) | + * +-----------------+---------------------------------------+ + * | X . . . . . . . | IDLE / nope frame indication (0 or 1) | + * +-----------------+---------------------------------------+ + * + * The bit number 7 (MSB) is set to high when either nothing has been + * detected, or during IDLE frames, so we can deliver noise levels, + * and avoid clock gaps on the L1 side. Other bits are ignored, + * and should be set to low (0) in this case. L16 shall be set to 0x00. + * + * == Coding of modulation and TS set number + * + * GMSK has 4 sets of training sequences (see tables 5.2.3a-d), + * while 8-PSK (see tables 5.2.3f-g) and the others have 2 sets. + * Access and Synchronization bursts also have several synch. + * sequences. + * + * +-----------------+---------------------------------------+ + * | 7 6 5 4 3 2 1 0 | bit numbers (value range) | + * +-----------------+---------------------------------------+ + * | . 0 0 X X . . . | GMSK, 4 TS sets (0..3) | + * +-----------------+---------------------------------------+ + * | . 0 1 0 X . . . | 8-PSK, 2 TS sets (0..1) | + * +-----------------+---------------------------------------+ + * | . 0 1 1 X . . . | AQPSK, 2 TS sets (0..1) | + * +-----------------+---------------------------------------+ + * | . 1 0 0 X . . . | 16QAM, 2 TS sets (0..1) | + * +-----------------+---------------------------------------+ + * | . 1 0 1 X . . . | 32QAM, 2 TS sets (0..1) | + * +-----------------+---------------------------------------+ + * | . 1 1 1 X . . . | RESERVED (0) | + * +-----------------+---------------------------------------+ + * + * NOTE: we only support GMSK and 8-PSK. + * + * == C/I: Carrier-to-Interference ratio + * + * The C/I value can be computed from the training sequence of each + * burst, where we can compare the "ideal" training sequence with + * the actual training sequence and then express that in centiBels. * * == Coding of the burst bits * @@ -731,6 +875,9 @@ static int trx_data_read_cb(struct osmo_fd *ofd, unsigned int what) return buf_len; } + /* Pre-clean (initialize) the flags */ + bi.flags = 0x00; + /* Parse the header depending on its version */ hdr_ver = buf[0] >> 4; switch (hdr_ver) { @@ -738,6 +885,9 @@ static int trx_data_read_cb(struct osmo_fd *ofd, unsigned int what) /* Legacy protocol has no version indicator */ hdr_len = trx_data_handle_hdr_v0(l1h, &bi, buf, buf_len); break; + case 1: + hdr_len = trx_data_handle_hdr_v1(l1h, &bi, buf, buf_len); + break; default: LOGPPHI(l1h->phy_inst, DTRX, LOGL_ERROR, "TRXD header version %u is not supported\n", hdr_ver); @@ -748,21 +898,39 @@ static int trx_data_read_cb(struct osmo_fd *ofd, unsigned int what) if (hdr_len < 0) return hdr_len; + /* TODO: we can use NOPE indications to get noise levels on IDLE + * TDMA frames, and properly drive scheduler if nothing has been + * detected on non-IDLE channels. */ + if (bi.flags & TRX_BI_F_NOPE_IND) { + LOGPPHI(l1h->phy_inst, DTRX, LOGL_NOTICE, + "IDLE / NOPE indications are not (yet) supported\n"); + return -ENOTSUP; + } + /* We're done with the header now */ buf_len -= hdr_len; + /* Handle burst bits */ switch (hdr_ver) { case 0: rc = trx_data_handle_burst_v0(l1h, &bi, buf + hdr_len, buf_len); break; + case 1: + rc = trx_data_handle_burst_v1(l1h, &bi, buf + hdr_len, buf_len); + break; + default: + /* Shall not happen, just to make GCC happy */ + OSMO_ASSERT(0); } /* Burst parsing error */ if (rc < 0) return rc; + /* TODO: also print TSC and C/I */ LOGPPHI(l1h->phy_inst, DTRX, LOGL_DEBUG, - "Rx UL burst (hdr_ver=%u) tn=%u fn=%u rssi=%d toa256=%d\n", + "Rx %s (hdr_ver=%u): tn=%u fn=%u rssi=%d toa256=%d\n", + (bi.flags & TRX_BI_F_NOPE_IND) ? "NOPE.ind" : "UL burst", hdr_ver, bi.tn, bi.fn, bi.rssi, bi.toa256); #ifdef TOA_RSSI_DEBUG |