Problems with understanding packet downlink assignment

Ivan Kluchnikov Ivan.Kluchnikov at
Thu Jun 28 13:43:17 UTC 2012

Hi, Andreas!

I am not sure that I understand question.
I think, if downlink assignment got lost (no response from mobile to
polling of downlink acknowledgement), we should try to establish this TBF
again (repeat  downlink assignment),  after that we should transmit in
established TBF all LLC PDUs recieved from SGSN .

2012/6/28 jolly <andreas at>

> hi,
> i try to unterstand downlink assignment. there are two ways to perform it:
> - on AGCH/PAGCH when mobile is in packet idle mode
> - on PACCH when mobile is in packet transfer mode (currently ongoing
> uplink TBF)
> (for establishment of uplink TBF in packet idle mode, the mobile repeats
> channel requests after one second timeout.)
> i don't see any procedure how the networks repeats a downlink
> assignment, if there is no response from the mobile (if downlink
> assignment got lost, hence it was not received by mobile). the only
> logical procedure i can see is that the messages from SGSN will get
> dropped during release of downlink TBF. (the release happens, because
> there is no response from mobile to polling of downlink acknowledgements.)
> regards,
> andreas

Ivan Kluchnikov.
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