An adaptive random access protocol for the collision channel without retransmissions

In traditional random multiple-access systems of the Aloha type, users take advantage of a feedback channel to monitor the fate of their previous transmissions and to schedule retransmissions of the packets lost in collisions. A variant of the implicit reservation Aloha in which there is feedback on channel events but no retransmission of lost messages is examined. Such a system is potentially free from buffer overflow and instability problems arising out of retransmissions. However, loss of packets due to collisions is a threat to data integrity. An approach for using coding to improve data integrity is outlined. Simulation results are presented showing that for certain combinations of parameters there is indeed a net positive gain in the normalized throughput due to coding.<>