Unbounded Contention Resolution in Multiple-Access Channels

Abstract

A frequent problem in settings where a unique resource must be shared among users is how to resolve the contention that arises when all of them must use it, but the resource allows only for one user each time. The application of efficient solutions for this problem spans a myriad of settings such as radio communication networks or databases. For the case where the number of users is unknown but fixed, recent work has yielded fruitful results for local area networks and radio networks, although either the solution is suboptimal or a (possibly loose) upper bound on the number of users needs to be known.

In this paper, we present the first (two) protocols for contention resolution in radio networks that are asymptotically optimal (with high probability), work without collision detection, and do not require information about the number of contenders. The protocols are evaluated and contrasted with the previous work by extensive simulations. These show that the complexity bounds obtained by the analysis are rather tight, and that the two protocols proposed have small and predictable complexity for all system sizes (unlike previous proposals).