About this Journal Submit a Manuscript Table of Contents
International Journal of Digital Multimedia Broadcasting
Volume 2010 (2010), Article ID 397824, 13 pages
http://dx.doi.org/10.1155/2010/397824
Research Article

On the Optimization of the IEEE 802.11 DCF: A Cross-Layer Perspective

1Electrical Engineering Department, Texas A&M University-Texarkana, Texarkana, TX 75505, USA
2DELEN, Politecnico di Torino, 10129 Torino, Italy

Received 5 May 2010; Accepted 20 October 2010

Academic Editor: Petros Nicopolitidis

Copyright © 2010 Massimiliano Laddomada and Fabio Mesiti. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper is focused on the problem of optimizing the aggregate throughput of the distributed coordination function (DCF) employing the basic access mechanism at the data link layer of IEEE 802.11 protocols. We consider general operating conditions accounting for both nonsaturated and saturated traffic in the presence of transmission channel errors, as exemplified by the packet error rate 𝑃 𝑒 . The main clue of this work stems from the relation that links the aggregate throughput of the network to the packet rate 𝜆 of the contending stations. In particular, we show that the aggregate throughput 𝑆 ( 𝜆 ) presents two clearly distinct operating regions that depend on the actual value of the packet rate 𝜆 with respect to a critical value 𝜆 𝑐 , theoretically derived in this work. The behavior of 𝑆 ( 𝜆 ) paves the way to a cross-layer optimization algorithm, which proved to be effective for maximizing the aggregate throughput in a variety of network operating conditions. A nice consequence of the proposed optimization framework relies on the fact that the aggregate throughput can be predicted quite accurately with a simple, yet effective, closed-form expression. Finally, theoretical and simulation results are presented in order to unveil, as well as verify, the key ideas.