Abstract: The present invention provides a method (500), device (400), microprocessor (500) and microprocessor memory (400, 500, 600) for instantaneous preemption of packet-switched data from a user that has won contention for a channel and for transmitting on a time slot, by higher priority traffic type data or voice in a TDMA communication system having a central access manager and a plurality of subscriber units. Before transmitting a packet on an uplink channel, the subscriber unit first selects a time slot and contends for channel access on the time slot. Upon gaining access to the uplink channel, the subscriber unit begins transmitting segments of a data packet on the selected time slot, suspending transmission when a higher priority user gains access to the time slot and, where decoding fails, suspending transmission for the time slot. The subscriber unit continues to transmit on the selected time slot until the packet ends.

Abstract: The method and device of the present invention provide for efficient error correction in a packet radio system by 1) eliminating wasted bandwidth due to the unnecessary retransmissions that occur as a result of lost positive acknowledgments, 2) occupying less downlink bandwidth than a scheme requiring positive acknowledgments, and 3) minimizing packet delay by providing two levels of error correction at the datalink layer.