Abstract

Random Medium-Access-Control (MAC) algorithms have played an increasingly important role in the development of wired and wireless Local Area Networks (LANs) and yet the performance of even the simplest of these algorithms, such as slotted-ALOHA, is still not clearly understood. In this talk, we provide a general and accurate method to analyze networks where interfering users share a resource using a random MAC algorithm. The method is based on mean-field theory and it is shown to be asymptotically exact when the number of users grows large; we further explain why it also provides extremely accurate performance estimates even for small systems. We apply the method to solve two open problems: (a) We address the stability region of buffered ALOHA systems. (b) We quantify the performance of adaptive MAC algorithms, such as the exponential back-off algorithm, in a system where saturated users interact through partial interference (by partial, we mean that a user does not necessarily interfere with all other users).