On the throughput capacity study for aloha mobile ad hoc networks

Despite extensive efforts on exploring the asymptotic capacity bounds for mobile ad hoc networks (MANETs), the general exact capacity study of such networks remains a challenge. As one step to go further in this direction, this paper considers two classes of Aloha MANETs (A-MANETs) NA and NC that adopt an aggressive traffic-independent Aloha and the conventional traffic-dependent Aloha, respectively. We first define a notation of successful transmission probability (STP) in NA, and apply queuing theory analysis to derive a general formula for the capacity evaluation of NA. We also prove that NC actually leads to the same throughput capacity as NA, indicating that the throughput capacity of NC can be evaluated based on the STP of NA as well. With the help of the capacity formula and stochastic geometry analysis on STP, we then derive closed-form expressions for the throughput capacity of an infinite A-MANET under the nearest neighbor/receiver transmission policies. Our further analysis reveals that although it is highly cumbersome to determine the exact throughput capacity expression for a finite A-MANET, it is possible to have an efficient and closed-form approximation to its throughput capacity. Finally, we explore the capacity maximization and provide extensive simulation/numerical results.