On the optimal design of MAC protocols in multi-hop ad hoc networks

In this paper, we present our results on the performance of MAC protocols in multi-hop wireless ad hoc networks in terms of the newly proposed metric “aggregate multi-hop information efficiency”. This metric captures the impact of the traffic conditions, the quality of service requirements for rate and correct packet reception, the number of hops and distance between a sender and its destination, and the outage probability for packet transmissions. Our network model considers a wireless network where nodes are distributed according to a homogeneous 2-D Poisson point process. Packet are generated following a Poisson distribution, and are forwarded to their destinations through a variable number of hops. Approximate expressions are derived for the outage probability of the ALOHA and CSMA MAC protocols, and validated with simulations. Various modifications of these protocols are considered, and their performances are compared. Moreover, an analytical procedure is presented to optimally design the communication so the multi-hop information efficiency performance of the network can be maximized.