Design and Analysis of Rate Aware Ad Hoc 802.11 Networks
802.11 WLANs are characterized by high bit error rate and frequent changes in network topology. The key feature that distinguishes WLANs from wired networks is the multi-rate transmission capability, which helps to accommodate a wide range of channel conditions. This has a significant impact on higher layers such as routing and transport levels. While many WLAN products provide rate control at the hardware level to adapt to the channel conditions, some chipsets like Atheros do not have support for automatic rate control. We first present a design and implementation of an FER-based automatic rate control state machine, which utilizes the statistics available at the device driver to find the optimal rate. The results show that the proposed rate switching mechanism adapts quite fast to the channel conditions.
The hop count metric used by current routing protocols has proven itself for single rate networks. But it fails to take into account other important factors in a multi-rate network environment. We propose transmission time as a better path quality metric to guide routing decisions. It incorporates the effects of contention for the channel, the air time to send the data and the asymmetry of links.
In this paper, we present a new design for a multi-rate mechanism as well as a new routing metric that is responsive to the rate. We address the issues involved in using transmission time as a metric and presents a comparison of the performance of different metrics for dynamic routing.
- Design and Analysis of Rate Aware Ad Hoc 802.11 Networks
- Book Title
- Distributed Computing and Networking
- Book Subtitle
- 8th International Conference, ICDCN 2006, Guwahati, India, December 27-30, 2006. Proceedings
- pp 409-420
- Print ISBN
- Online ISBN
- Series Title
- Lecture Notes in Computer Science
- Series Volume
- Series ISSN
- Springer Berlin Heidelberg
- Copyright Holder
- Springer-Verlag Berlin Heidelberg
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- Editor Affiliations
- 16. Department of Computer Science, Iowa State University
- 17. Computer Science Department SUNY at Stony Brook Stony Brook
- 18. Department of Computer Science & Engineering, Indian Institute of Technology
- 19. Dept. of Electrical and Computer Engineering, Iowa State University
- Author Affiliations
- 20. Computer Science & Automation Indian Institute of Science, Bangalore
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