Priority-Based Multi-event Reporting in Hybrid Wireless Sensor Networks

Evolution in Wireless Sensor Networks (WSNs) has allowed new applications that led to an increase in the complexity of communication protocols. This in turn has led to the study of additional Quality of Service (QoS) parameters in order to provide an acceptable system performance. As such, hybrid algorithms that allow sensor networks to perform continuous monitoring (CntM) and event driven detection (EDD) duties have proven their value in different environments where emergency alarms are required in addition to a permanent surveillance of the phenomena, specially when considering time-critical applications. Furthermore, priority assignment may help reduce report delay and enhance transmission probability in important packets, specifically when different types of events are considered or certain data from the same event has higher relevance to the end user than the rest of the packets. In this paper, event report delay and energy consumption in a priority-based hybrid WSN protocol is studied using a Markov chain, when considering a two-priority event detection scheme in a hybrid WSN. Results show that, by using different transmission probabilities, assigned to high and low priority data packets, event reporting delay can be reduced, representing better performance for critical-time applications. On the other hand, energy consumption and network lifetime are not affected by the selected priority assignment scheme.