diff options
| author | Vadim Yanitskiy <vyanitskiy@sysmocom.de> | 2022-03-17 17:51:35 +0300 |
|---|---|---|
| committer | fixeria <vyanitskiy@sysmocom.de> | 2022-04-05 13:45:31 +0000 |
| commit | 5a8413166f61046f15e8356ed069effee33d72f3 (patch) | |
| tree | 640a0725b3086c4e5fc8da6bcb554c100e532257 | |
| parent | 12b3921a4acb30b847acc5f7e61d031f1b2ab571 (diff) | |
osmo-bts-trx: rx_{tchh,tchf}_fn(): use AMR CMI lookup tables
3GPP TS 45.009 defines that Codec Mode Indications shall be sent
with speech frames having specific TDMA frame numbers of their
*first* bursts, which are defined in tables 3.2.1.3-{1,2,3,4}.
Performance-wise it's batter to have these tables implemented as
arrays, rather then using the 'switch' statement. We can simplify
things even further and have TDMA frame numbers corresponding to
the *last* bursts in them. This eliminates the need of doing an
additional last-to-first mapping, so that bi->fn can be used.
Change-Id: I46def864729c8f9063af201750456771ea5558d5
| -rw-r--r-- | src/osmo-bts-trx/sched_lchan_tchf.c | 3 | ||||
| -rw-r--r-- | src/osmo-bts-trx/sched_lchan_tchh.c | 11 | ||||
| -rw-r--r-- | src/osmo-bts-trx/sched_utils.h | 18 |
3 files changed, 20 insertions, 12 deletions
diff --git a/src/osmo-bts-trx/sched_lchan_tchf.c b/src/osmo-bts-trx/sched_lchan_tchf.c index c8ad383d..6a9a0f0f 100644 --- a/src/osmo-bts-trx/sched_lchan_tchf.c +++ b/src/osmo-bts-trx/sched_lchan_tchf.c @@ -131,8 +131,7 @@ int rx_tchf_fn(struct l1sched_ts *l1ts, const struct trx_ul_burst_ind *bi) * the first FN 4,13,21 defines that CMR is included in frame. * NOTE: A frame ends 7 FN after start. */ - fn_begin = trx_sched_lookup_fn(chan_state, 8); - amr_is_cmr = !ul_amr_fn_is_cmi(fn_begin); + amr_is_cmr = !sched_tchf_ul_amr_cmi_map[bi->fn % 26]; /* The AFS_ONSET frame itself does not result into an RTP frame * since it only contains a recognition pattern that marks the diff --git a/src/osmo-bts-trx/sched_lchan_tchh.c b/src/osmo-bts-trx/sched_lchan_tchh.c index 1778d369..369e35b2 100644 --- a/src/osmo-bts-trx/sched_lchan_tchh.c +++ b/src/osmo-bts-trx/sched_lchan_tchh.c @@ -165,16 +165,7 @@ int rx_tchh_fn(struct l1sched_ts *l1ts, const struct trx_ul_burst_ind *bi) break; } - /* Calculate the frame number where the block begins. Note that - * we need to traverse the measurement histort back by 6 bursts, - * not by 4 bursts. The reason for this is that the burst shift - * buffer we use for decoding is 6 bursts wide (one SACCH block) but - * TCH/H blocks are only 4 bursts wide. The decoder functions look - * at the beginning of the buffer while we shift into it at the end, - * this means that TCH/H blocks always decoded delayed by two frame - * number positions late. */ - fn_begin = trx_sched_lookup_fn(chan_state, 6); - fn_is_cmi = ul_amr_fn_is_cmi(fn_begin); + fn_is_cmi = sched_tchh_ul_amr_cmi_map[bi->fn % 26]; /* See comment in function rx_tchf_fn() */ amr = 2; diff --git a/src/osmo-bts-trx/sched_utils.h b/src/osmo-bts-trx/sched_utils.h index f76e49bb..398083d9 100644 --- a/src/osmo-bts-trx/sched_utils.h +++ b/src/osmo-bts-trx/sched_utils.h @@ -37,6 +37,24 @@ static inline uint16_t compute_ber10k(int n_bits_total, int n_errors) return 10000 * n_errors / n_bits_total; } +/* 3GPP TS 45.009, table 3.2.1.3-{1,3}: AMR on Uplink TCH/F */ +static const uint8_t sched_tchf_ul_amr_cmi_map[26] = { + [7] = 1, /* TCH/F: first=0 / last=7 */ + [16] = 1, /* TCH/F: first=8 / last=16 */ + [24] = 1, /* TCH/F: first=17 / last=24 */ +}; + +/* 3GPP TS 45.009, table 3.2.1.3-{2,4}: AMR on Uplink TCH/H */ +static const uint8_t sched_tchh_ul_amr_cmi_map[26] = { + [6] = 1, /* TCH/H(0): first=0 / last=6 */ + [15] = 1, /* TCH/H(0): first=8 / last=15 */ + [23] = 1, /* TCH/H(0): first=17 / last=23 */ + + [7] = 1, /* TCH/H(1): first=1 / last=7 */ + [16] = 1, /* TCH/H(1): first=9 / last=16 */ + [24] = 1, /* TCH/H(1): first=18 / last=24 */ +}; + /*! determine whether an uplink AMR block is CMI according to 3GPP TS 45.009. * \param[in] fn_begin frame number of the beginning of the block. * \returns true in case of CMI; false otherwise. */ |