Cooperative and Non-cooperative Models for slotted-Aloha type MAC protocols

摘要

Aloha and its slotted variation have been widely deployed as a medium access control (MAC) protocol for different communication networks. Slotted-Aloha type MAC protocols don't perform carrier sensing and synchronize the transmissions into time-slots. These protocols are suitable for controlling multiple accesses when nodes cannot sense each other. Recent development of wireless and sensor networks urges us to re-investigate slotted-Aloha type MAC, and to design its variations for these new trends. Early research had focused on the stability control aspect of the protocol, a recent work discusses the stability of slotted-Aloha with selfish user behaviors and perfect information. In this paper, we focus on the performance issues of slotted-Aloha type MAC protocol with selfish nodes. We propose a generalized Markov model for slotted-Aloha protocol and do not assume that each node has perfect information. We analyze the performance of the protocol when nodes are either cooperative or non-cooperative. The main results are: (1) Under cooperative selfish behaviors, one half of the medium utilization is achievable. (2) Under non-cooperative selfish behaviors, medium utilization collapses and Prisoner's Dilemma characterizes the situation.