Utility-Optimal Medium Access Control: Reverse and Forward Engineering

— This paper analyzes and designs medium access control (MAC) protocols for wireless ad-hoc networks through the network utility maximization (NUM) framework. We first reverse-engineer the current exponential backoff (EB) type of MAC protocols such as the BEB (binary exponential backoff) in the IEEE 802.11 standard through a non-cooperative gametheoretic model. This MAC protocol is shown to be implicitly maximizing, using a stochastic subgradient, a selfish local utility at each link in the form of expected net reward for successful transmission. While the existence of a Nash equilibrium can be established, neither convergence nor social welfare optimality is guaranteed due to the inadequate feedback mechanism in the EB protocol. This motivates the forward-engineering part of the paper, where a network-wide utility maximization problem is formulated, using a collision and persistence probability model and aligning selfish utility with total social welfare. By adjusting the paramet...

• Type: Conference
• Year: 2006
• Where: INFOCOM
• Authors: Jang-Won Lee, Mung Chiang, A. Robert Calderbank
• Keywords: Communications, INFOCOM 2006, MAC Protocol, NUM Problem, Utility Maximization