STELE: A Simple Technique for Local delay Estimation in WSN

Traditional techniques for delay calculation between neighbor nodes involve the exchange of frames and assume link symmetry. This approach, besides being costly in terms of energy, is not a good fit for wireless sensor networks, where links are typically asymmetric. On the other hand, MAC layer timestamps eliminate the asymmetry problem, but depend on specific hardware. In this paper, we present a Simple Technique for Local delay Estimation (STELE) which is hardware independent, eliminates the need for bidirectional communication, and is therefore applicable to asymmetric links. Furthermore, experimental results with real sensors motes indicate that STELE is energy efficient in comparison to existing methods.