A Wave-Based Request-Response Protocol for Latency Minimization in WSNs

Transmission latency is a key performance metrics in most wireless sensor network (WSN) applications. Nodes in a WSN often keep their radio transceivers off, and turn them on periodically using a duty cycling mechanism. The latter is a major source of delay in the network, because transmissions must wait for the next receiver wake-up. In this paper, we present a cross-layer approach to minimize latency of a request-response (RR) protocol adopted in an IEEE 802.15.4-based WSN where the IPv6 routing protocol for low-power and lossy networks (RPLs) is used. Extra wake-ups are generated dynamically to match the predicted arrival time of the response packet, in order to reduce the duty cycling delay. The proposed approach is verified with the Cooja simulator, relying on the Contiki operating system (OS). The observed experimental results show a shorter RR delay with respect to a phase alignment (PA) approach.