Patent ID: 7525908

Claim:
Data unit management apparatus for use in communications receiving equipment in receiving data units over a transmission link, the apparatus comprising: a data unit reception monitor for monitoring receipt of data units via a logical channel; a retransmission request sender for triggering the sending of at least one retransmission request in respect of one or more missing or corrupted data units; and a retransmitted data unit monitor for monitoring receipt of one or more retransmitted data units via the logical channel, wherein the retransmitted data unit monitor comprises a timer for timing a predetermined period, and is configured to monitor receipt within the predetermined period of retransmitted data units and to trigger at least one repeat retransmission request in the event that no data units subject to an earlier retransmission request are received within the associated predetermined period, the retransmitted data unit monitor being configured to trigger up to a predetermined number of such repeat retransmission requests in respect of said earlier retransmission request, such that a recovery mechanism is initiated in the event that no data units subject to the earlier retransmission request are received via the logical channel within the associated predetermined periods.