Project

General

Profile

Bug #3055

osmo-bts-trx: slow TA loop feedback

Added by fixeria 9 months ago. Updated about 2 months ago.

Status:
New
Priority:
Normal
Assignee:
Category:
osmo-bts-trx
Target version:
-
Start date:
03/10/2018
Due date:
% Done:

0%

Spec Reference:

Description

There is probably an issue of TA loop in osmo-bts-trx: if a delay between
MS and BTS is changed with a big step, e.g. from 0 to 2048 symbol periods,
then a new Timing Advance value would be changed too slow, i.e. step by
step after each measurement period => changing ToA from 0 to 2048 will take
2048 / 256 = 8 measurement periods to compensate the loop...

How to reproduce?

Use both FakeTRX and trxcon from OsmocomBB. There is an auxiliary
command 'FAKE_TOA', which is intended to simulate a delay between MS and BTS:

https://osmocom.org/projects/baseband/wiki/FakeTRX
https://git.osmocom.org/osmocom-bb/commit/?h=fixeria/trx&id=5ab622d2b72ac6df9d71d42736a6a65ac76cfab5


Related issues

Related to OsmoBTS - Feature #1851: generalize power control and TA loop codeNew2016-11-18

Related to OsmocomBB - Bug #2988: unexpected bit errors when using trxcon and osmo-bts-trxResolved2018-02-23

History

#1 Updated by laforge 9 months ago

  • Related to Feature #1851: generalize power control and TA loop code added

#2 Updated by laforge 9 months ago

  • Assignee set to sysmocom

#3 Updated by fixeria 9 months ago

  • Related to Bug #2988: unexpected bit errors when using trxcon and osmo-bts-trx added

#4 Updated by laforge 6 months ago

We now have a wiki page about timing advance: Timing_Advance

#5 Updated by laforge about 2 months ago

  • Assignee changed from sysmocom to tnt

Also available in: Atom PDF

Add picture from clipboard (Maximum size: 48.8 MB)