Auto-controlled algorithm for slotted ALOHA

A multiple power level transmission system increases the maximum throughput by selecting the power levels randomly, showing the same behaviour as the standard slotted ALOHA, where the throughput decreases abruptly at higher traffic load conditions. An auto-controlled slowly decreasing throughput algorithm for slotted ALOHA is developed. Herein, a mobile terminal can transmit any packet at a higher probability at the lower power levels that increases the probability of only one packet at the highest power levels and thereby augmenting the capture probability. If the traffic load is high, the probability of interfering packets at the same slot increases. Consequently, the transmission probability at the lower power levels increases and the probability of exactly one packet at the highest power levels remains unaltered. As a result, the system is automatically controlled, since it does not need any extra information about the network. Therefore, it is very attractive from an implementation point of view for the emerging mobile networking environment. Extensive comparisons show that the proposed auto-controlled algorithm demands remarkable throughput performance compared with the traditional random power level selection algorithm particularly with a very high retransmission probability.