Practical Rate and Route Adaptation with Efficient Link Quality Estimation for IEEE 802.11b/g Multi-Hop Networks

Abstract

Accurate and fast packet delivery ratio (PDR) estimation, used in evaluating wireless link quality, is a prerequisite to increase the performance of multi-hop and multi-rate IEEE 802.11 wireless networks.Unfortunately, contemporary PDR estimation methods, i.e. beacon-based packet counting in Estimated Transmission Time and Expected Transmission Count metrics, have unsatisfactory performance. Therefore, in this paper we propose a novel PDR estimation method based on SNR profiles and special broadcast packets. We classify all possible link quality estimation (LQE) sources and compare them analytically against our design, showing the superiority of our approach. Further investigations with the prototype implementation of our method in IEEE 802.11b/g testbeds reveal that the LQE accuracy in some scenarios can be improved up to 50% in comparison to generic beacon packet-based LQE. The proposed method is used in novel rate adaptation process, while these two methods are jointly used in the routing process. Experiments in different measurement scenarios show that the advanced LQE leads to a better rate adaptation and route selection in the form of end-to-end throughput increase, compared to traditional LQE methods.