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Feature #3906

Automatically adjust LAPDm timer values with 'fn-advance' parameter

Added by fixeria about 1 month ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
osmo-bts-trx
Target version:
-
Start date:
04/06/2019
Due date:
% Done:

0%

Spec Reference:

Description

Currently we use fn-advance=20 by default, so the burst scheduler is working 20 TDMA frames in advance. This advance gives the transceiver some time to receive a burst, process it (i.e. modulate), and send to the Tx buffer of SDR. As a side effect, this increases the delay between UL and DL: 20 TDMA frames => 92.3ms of delay.

Higher fn-advance values cause a longer delay, resulting in LAPDm frame retransmissions.
OsmoBTS should automatically adjust LAPDm timer values with the configured 'fn-advance' value.


Related issues

Related to OsmoBTS - Bug #3506: FACCH LAPDm sequence error (state LAPD_STATE_MF_EST)Feedback2018-08-28

History

#1 Updated by fixeria about 1 month ago

  • Related to Bug #3506: FACCH LAPDm sequence error (state LAPD_STATE_MF_EST) added

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