John Heidemann

Contention Analysis of MAC Protocols that Count

TitleContention Analysis of MAC Protocols that Count
Publication TypeConference Paper
Year of Publication2010
AuthorsA. A. Syed, and J. Heidemann
Date Publishedsep
Conference LocationWoods Hole, Massachusetts, USA

The key aspect in the design of any contention-based medium access control (MAC) protocol is the mechanism to measure and resolve simultaneous contention. Generally, terrestrial wireless MACs can only observe success or collision of a contention attempt through carrier sense. An implicit estimate of the number of contenders occurs through repeated observation and changing back-off contention window. Recent work in underwater MAC protocols suggest there it is possible to directly \emphcount the number of contenders by exploiting the spatio-temporal uncertainty inherent to high-latency underwater acoustic medium. Prior work has shown how to use counting in underwater MACs, and how to optimize contention windows in radio MACs. In this paper, we quantify bounds to convergence time for MAC protocols employing exact contender counting. We show that perfect countingallows \emphcontention to converge quickly, \emphindependent of network density, with an asymptotic limit of \emph3.6 contention rounds on average. We confirm this analysis with simulation of a specific underwater MAC protocol, and suggest the opportunity for the results to generalize for any radio-based MACs that estimate contenders.