RESOLVED: State of Frequency Hopping in OpenBSC

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Harald Welte laforge at gnumonks.org
Mon Jun 21 10:24:53 UTC 2010


Hi all!

As it turns out, the BTS side of the hopping was working all the time.
However, the phones discarded our IMMediate ASSignment message due to
an erroneous L2 Pseudo Length.

This has been fixed in git commit cfa4a01c8fe2b5f2ab1bfa6fcf23c35ff5e957f4 and
the hopping is working fine using the patch and config that I've sent in the
last message.

Please note the BS-11 does synthesizer hopping, so it can hop over any
number of channels.  I haven't tested more than 8, but you can definitely
hop over 8 ARFCN.

Only TRX1 will hop, as TRX0 needs to remain on a constant ARFCN for the
CCCH/BCCH.  I suggest to use 'channel allocator descending' for testing,
as the BSC will then always prefer allocating channels from TRX1, even if
suitable channels on TRX0 is still unused.

Thanks to Dieter for verifying the BS-11 actually does hopping using his
Racal 6113 analyzer, and thanks to Sylvain for his suggestion to check
the L2 pseudo length.

Regards,
	Harald
-- 
- Harald Welte <laforge at gnumonks.org>           http://laforge.gnumonks.org/
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