document RACH tuning parameters more thoroughly, give explanations
Like any GSM network, we do have parameters such as
rach max retransmission and
rach tx integer that influence the RACH load (and RACH/IMM-ASS delay).
Users on lightly loaded networks with few users need different defaults than users o highly [over]loaded cells.See also:
- http://gsm-optimization.blogspot.de/2012/04/tx-integer.html for some general recommendations + rationale
- http://lists.osmocom.org/pipermail/openbsc/2009-December/002366.html for the OsmoBSC defaults + rationale
- GSM TS 04.08 section 188.8.131.52.2 and 10.5.2.29
- higher tx-integer will be better for high-load, but will increase the delay of a MS getting any channel
- higher max-retransmissions means higher rach-load on the cell as the MS will make more re-tries. However, higher chance that it will get through, even in adverse radio conditions.
Let's make sure we give proper advice to our users.