Generalized Slotted Aloha Revisited: A Throughput and Stability Analysis

We consider the uplink case of a cellular system where m bufferless mobiles transmit over a common channel to a base station, using the slotted aloha medium access protocol. We study the performance of this system under a new transmission scheduling scheme. In contrast to slotted aloha, each new arrival packet is first transmitted at a probability pa and retransmitted later, if needed, with probability qr. Under this proposal, we analyze the cooperative team in which a common goal is jointly optimized. Later, we derive the average throughput and the expected delay and use them as the objectives to optimize. We further study the impact of parameters on the average throughput as well as the expected delay. Furthermore, we address the stability behavior of our new scheme. We finally carry out extensive numerical examples to illustrate the obtained gain which concerns, in particular, the expected delay minimization.