Fair bandwidth sharing in distributed systems: a game-theoretic approach

Fair sharing of bandwidth remains an unresolved issue for distributed systems. In this paper, the users of a distributed LAN are modeled as selfish users with independence to choose their individual strategies. With these selfish users, the contention-based distributed medium access scenario is modeled as a complete-information, noncooperative game, designated the "access game". A novel MAC strategy based on p-persistent CSMA is presented to achieve fairness in the "access game". It is proven that there are an infinite number of nash equilibria for the "access game", but they do not result in fairness. Therefore, it may be beneficial for the selfish users to adhere to a set of constraints that result in fairness in a noncooperative fashion. This leads to the formulation of a constrained "access game" with fairness represented as a set of algebraic constraints. It is proven that the solution of the constrained game, the constrained nash equilibrium, is unique. Further, it is shown that, in addition to achieving fairness, this solution also optimizes the throughput. Finally, these results are extended to a more realistic incomplete-information scenario by approximating the incomplete-information scenario as a complete-information scenario through information gathering and dissemination.