This article is part of the series Quality of Service in Mobile Ad Hoc Networks.

Open Access Research Article

Traffic Agents for Improving QoS in Mixed Infrastructure and Ad Hoc Modes Wireless LAN

Yang Yang1*, Hai-Feng Yuan2, Hsiao-Hwa Chen3, Wen-Bing Yao2 and Yong-Hua Song2

Author Affiliations

1 Department of Electronic and Electrical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom

2 School of Engineering and Design, Brunel University, Uxbridge UB8 3PH, United Kingdom

3 Institute of Communications Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan

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EURASIP Journal on Wireless Communications and Networking 2006, 2006:094235 doi:10.1155/WCN/2006/94235


The electronic version of this article is the complete one and can be found online at: http://jwcn.eurasipjournals.com/content/2006/1/094235


Received:12 July 2005
Revisions received:5 December 2005
Accepted:28 December 2005
Published:7 March 2006

© 2006 Yang et al.

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.

As an important complement to infrastructured wireless networks, mobile ad hoc networks (MANET) are more flexible in providing wireless access services, but more difficult in meeting different quality of service (QoS) requirements for mobile customers. Both infrastructure and ad hoc network structures are supported in wireless local area networks (WLAN), which can offer high data-rate wireless multimedia services to the mobile stations (MSs) in a limited geographical area. For those out-of-coverage MSs, how to effectively connect them to the access point (AP) and provide QoS support is a challenging issue. By mixing the infrastructure and the ad hoc modes in WLAN, we propose in this paper a new coverage improvement scheme that can identify suitable idle MSs in good service zones as traffic agents (TAs) to relay traffic from those out-of-coverage MSs to the AP. The service coverage area of WLAN is then expanded. The QoS requirements (e.g., bandwidth) of those MSs are considered in the selection process of corresponding TAs. Mathematical analysis, verified by computer simulations, shows that the proposed TA scheme can effectively reduce blocking probability when traffic load is light.

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