Multislot allocation failures and defects

Andreas Eversberg andreas at eversberg.eu
Sat Jan 4 15:19:34 UTC 2014


Holger Hans Peter Freyther wrote:
> * select_first_ts (it exists after the refactoring). It initializes
>   i and compares it but it will never increment it. This means that
>   the code can look at PDCHs _outside_ of the tx_range.
>
> * first_common_ts handling. When assigning the DL tbf we pick a
>   first_common_ts but when the actual UL assignment happens there
>   might not be a free USF on the Uplink and at that point the phone
>   might not listen on the TS we think.
>
> * Sum for Rx+Tx is not used. I see that in update_rx_win_max you
>   modify the window to make some room.
>
> * select_ul_slots. "i" is not incremented in all cases which could
>   potentially lead to using slots outside of the tx_range. For the
>   MS Type == 1 handling you could introduce a different variable that
>   counts how many slots were used?
>   
dear holger,

i added serveral fixes that showed up with your test code. i have pushed
them to the jolly/allocation-fixes branch. in also includes a fix for
the missing incrementation of 'i' in select_first_ts() and
select_ul_slots().

the Sum variable is not used, because the algorithm assigns only one
uplink time slot. the supports RX slots plus 1 TX slot never exceeds the
Sum.

i have no fix for the USF problem. if the first_common_ts on concurrent
TBFs is different, we should reject the TBF by sending a Packet Access
Reject, but this message is also not implemented.

regards,

andreas





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