Do We Really Need a Priori Link Quality Estimation?

Abstract

Traditionally, link quality estimation (LQE) has been viewed as an a priori step in sensor network routing protocols because it filters out unreliable links before data transmission. Recent results, however, show that protocols can perform well without a priori LQE. Because getting rid of LQE seems rather counter-intuitive, the aim of this work is to look deeper into the behavior of LQE-free protocols. Our results, based on one of the stateof-the-art LQE-free protocols, show two interesting insights. First, LQEfree protocols manage to choose links that are slightly better than the ones obtained with a priori LQE methods. Second, in traditional protocols, the effort needed to identify good links accounts for 40% to 60% of the energy consumption of nodes. By eliminating this overhead, LQE-free protocols can save a significant amount of energy compared to standard approaches. On the other hand, clear downsides of LQE-free operation are the longer paths and the worse load balance. The latter poses a higher transmission burden on some nodes.