A high-throughput routing metric for multi-hop Ad hoc networks based on real time testbed

This paper presents an high-throughput routing metric, which concentrates on optimizing the behavior of expected transmission count metric (ETX) in real-world multi-hop Ad hoc networks. In practical applications, ETX metric always fluctuates over time even in fixed scenarios, and does not incorporate the effects of gray area and fluctuating links. Considering these drawbacks, we devise the average expected transmission count with threshold metric (AETXT). Compared to ETX, AETXT makes two improvements: 1) with incorporating average ETX (AETX) instead of ETX as the criterion of link quality, AETXT balances the consistency and flexibility of ETX values; 2) With introducing a threshold to AETX, AETXT incorporates the effects of gray area and fluctuating links; The packet loss is sufficient low when AETX is less than the threshold, while it varies dramatically for AETX surpassing the threshold. This paper describes the design and implementation of AETXT as a metric for DSR routing protocol. Measurements taken from a 10-node 802.11b testbed demonstrate that when the path length gets to 5 AETXT outperforms ETX by 50%, 14.7%, 5.8% and 5.7% in terms of TCP throughput, UDP throughput, TCP packet loss and UDP packet loss, respectively. It is worth underling that measurements prove that AETXT outperforms ETX greatly when transferring real-time multimedia streams like live video.