QoS based event delivery for disaster monitoring applications

As Wireless Sensor Networks (WSN) become more technically mature, we are observing more deployment that is widespread. Disaster Monitoring and Recovery is one area receiving recent attention in the field. Here, due to hostile terrains or dangerous settings, standard manual or wired detections are not feasible. In situ WSN have the potential to analyze conditions and make predictions regarding dangerous situations potentially saving lives. However, this situation brings many challenges for the WSN in terms of event detection and the subsequent relaying of that event notification to the devices/systems/people that require it. The latter is the focus of this paper. Given the general unreliability of WSNs, there is a demand for Quality of Service driven mechanisms that can ensure that event data is delivered reliably and timely as required by the application. To this end, we present a novel Priority-Based Random Re-routing protocol (PB-RRR). We evaluate our protocol using both an analytical model and a 34-node proof-of-concept sensor deployment. We introduce five QoS levels that progressively improve high priority message throughput from best-effort to reliable event message delivery. We evaluate how congestion, proportions of priority event nodes/messages, and decision threshold affects message delay for each QoS level.