An Optimum Retransmission Cut-Off Scheme for Slotted ALOHA

The retransmission cut-off is not needed for a stable operation of slotted ALOHA if the new packet generation rate is below a critical limit. The throughput never reaches its maximum value if the new packet generation rate is less than this critical limit irrespective of the number of transmissions. The maximum throughput is attained by adjusting the number of transmissions, pertaining to the new packet generation rate exceeding the critical limit. A complete analysis for the new packet generation rate with the proper adjustment of the number of transmissions that maximize the channel throughput in a Rayleigh fading channel is executed. A stable operating region in terms of the packet rejection probability and the corresponding number of transmissions is devised.