PS-QUASAR: A publish/subscribe QoS aware middleware for Wireless Sensor and Actor Networks

It has been more than 30 years since the first research into Wireless Sensor and Actor Networks appeared. However, WSANs are still not a ubiquitous technology due to several factors which include a lack of Quality of Service (QoS) support or the absence of high level programming models. New applications with heterogeneous QoS requirements where WSANs can be successfully applied, such as Critical Infrastructure Protection (CIP), have been recognized. PS-QUASAR, a middleware for WSANs that deals with these two issues, offers a high level simple programming model based on the publish/subscribe paradigm. In this model all nodes in the network are potential publishers of each of the topics. PS-QUASAR also handles QoS (reliability, deadline, priority) and supports a many-to-many exchange of messages between nodes in a fully distributed way by means of multicasting techniques. Performance evaluation via simulation using the Contiki operating system shows that the protocol can handle multiple publishers and subscribers at the same time whilst dealing with QoS requirements.