Performance Evaluation of Link Quality Estimation Metrics for Static Multihop Wireless Sensor Networks

The lossy nature of wireless communication leads to many challenges while designing multihop networks. As an integral part of reliable communication in wireless networks, effective link estimation is essential for routing protocols. Recent studies have shown that link reliability-based metrics like ETX have better performance than traditional metrics such as hop count or latency. Usually, such metrics employ techniques like blacklisting, involving thresholds during the link estimation process. In this paper, we conduct a detailed performance analysis of three commonly used link-quality metrics in wireless sensor networks: ETX, 4Bit, and RNP. We study the interplay between these metrics and CTP, a tree-based routing protocol provided by TinyOS. The objectives of our experiment are two fold. First, by applying different link-quality metrics to the same routing protocol, we provide extensive evaluation on ETX, 4Bit and RNP with insights on their performance under different criteria. Second, we study the impact of the presence or absence of a blacklisting policy when using these link quality estimation metrics. As to our knowledge, this paper is the first to compare the performance between these link quality based metrics with networks of different qualities under realistic conditions.