fixeria has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-bts/+/27941 )
Change subject: osmo-bts-trx: rx_tchf_fn(): do not treat AFS_SID_UPDATE as SUB frame ......................................................................
osmo-bts-trx: rx_tchf_fn(): do not treat AFS_SID_UPDATE as SUB frame
We have two similar values in enum gsm0503_amr_dtx_frames:
* AFS_SID_UPDATE - precursor of SID UPDATE, * AFS_SID_UPDATE_CN - the actual SID UPDATE.
The former is internally used by libosmocoding to mark the current frame as a precursor of the actual SID UPDATE frame - the later.
+---+---+---+---+---+---+---+---+ | _ | _ | _ | _ | a | b | c | d | AFS_SID_UPDATE +---+---+---+---+---+---+---+---+ | a | b | c | d | _ | _ | _ | _ | AFS_SID_UPDATE_CN +---+---+---+---+---+---+---+---+ ^ | | We're here.
Do not treat the precursor frames as a SUB frames, as they contain no information (rc=-1) and usually have *expected* BER ~50%. This fixes unexpected RXQUAL-SUB > 0 in the Uplink measurements during DTX.
Change-Id: I46f32bbbcb6284615d05b8703945c5ca4da55b92 Related: SYS#5853 --- M src/osmo-bts-trx/sched_lchan_tchf.c 1 file changed, 5 insertions(+), 1 deletion(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bts refs/changes/41/27941/1
diff --git a/src/osmo-bts-trx/sched_lchan_tchf.c b/src/osmo-bts-trx/sched_lchan_tchf.c index 20abfe1..d527a41 100644 --- a/src/osmo-bts-trx/sched_lchan_tchf.c +++ b/src/osmo-bts-trx/sched_lchan_tchf.c @@ -171,7 +171,11 @@ "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; + /* ... except AFS_SID_UPDATE, which is in fact a precursor of + * the actual SID UPDATE frame (AFS_SID_UPDATE_CN) and only + * used internally by gsm0503_tch_afs_decode_dtx() */ + if (chan_state->amr_last_dtx != AFS_SID_UPDATE) + is_sub = 1; }
/* The occurrence of the following frames indicates that we