hi ghamiz,
If this feature is enabled the duration of UL TBF will be extend in order to quicly restart the data transmission in UL if higher layers in the MS deliver the new data,without having to re-establish a new UL TBF,after the countdown procedure has started.E.g to maintain the UL TBF established,some time after the last block(CV=0)has been acknowledge by the network.During inactivity period the BSS should keep the USF schedueling & reception of the UL RLC data block as long as uplink TBF is in extended phase.