Title: Modelling and analysis of bandwidth competition in 802.11 wireless networks

Authors: Qijun Gu, Chao-Hsien Chu, Peng Liu

Addresses: Department of Computer Science, Texas State University, San Marcos, USA. ' College of Information Sciences and Technology, Pennsylvania State University, University Park, USA. ' College of Information Sciences and Technology, Pennsylvania State University, University Park, USA

Abstract: In a wireless network, bandwidth is shared and nodes are in fact |competing| with each other for resources. Therefore, the Quality of Service (QoS) an individual node can offer to applications is determined by how intense the competition is and how much bandwidth it can win in the competition. In this paper, we propose a Markov chain model to study the bandwidth competition in 802.11 networks. A set of heuristic formulas are derived to analyse and predict bandwidth competition. The formulas can be used to compute the exact quantity of bandwidth allocated to competing nodes, given their demands and their traffic parameters. It is illustrated that nodes that demand the same amount of bandwidth may receive very different allocations, and nodes that demand more bandwidth do not always obtain more bandwidth than other nodes. The findings in this study imply that (1) nodes can share the bandwidth precisely according to their demands with full cooperation, (2) or a node can guarantee its own bandwidth while suppressing others with a deliberate consideration in composing packets.

Keywords: Markov chain; bandwidth competition; IEEE 802.11; wireless LANs; congestion; wireless networks; local area networks; quality of service; QoS.

DOI: 10.1504/IJMNDI.2007.017323

International Journal of Mobile Network Design and Innovation, 2007 Vol.2 No.3/4, pp.190 - 201

Available online: 26 Feb 2008 *

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