Attention is currently required from: laforge, fixeria. Hello Jenkins Builder,

I'd like you to reexamine a change. Please visit

https://gerrit.osmocom.org/c/osmo-bts/+/27836

to look at the new patch set (#3).

Change subject: osmo-bts-trx: check if scheduling of [dummy] FACCH/H is allowed ......................................................................

osmo-bts-trx: check if scheduling of [dummy] FACCH/H is allowed

Currently (without this patch) if tch_dl_dequeue() yields nothing we're scheduling dummy FACCH/H *regardless* if it's permitted to start at the given TDMA FN or not. This may result in misaligned FACCH transmission, so the MS will not able to decode anything and will report BER>0.

With this patch applied we a) schedule FACCH if it's allowed to start at the current TDMA FN; b) send whatever was in the burst buffer (garbage) if FACCH/H is not permitted. This is the best we can do without introducing additional complexity.

This patch does not guard against sporadic gaps in the Downlink TCH queue. However when tch_dl_dequeue() constantly yields nothing, e.g. when we end up with a codec mismatch, then this additional check saves us from starting misaligned FACCH/H transmission. If we start at a wrong TDMA offset, then all subsequent FACCH frames will be scheduled at wrong offsets and thus none of them will be decoded by the MS.

Change-Id: I6f8af140a6ccf3d5fd7b98f6cb5c18e2c5e2f61b Related: SYS#5919, OS#4823 --- M src/common/scheduler.c M src/osmo-bts-trx/sched_lchan_tchh.c 2 files changed, 9 insertions(+), 1 deletion(-)

git pull ssh://gerrit.osmocom.org:29418/osmo-bts refs/changes/36/27836/3