A reliable data transport protocol for partitioned actors in Wireless Sensor and Actor Networks

In Wireless Sensor and Actor Networks (WSANs), effective Actor-Actor Communication (AAC) is an important requirement for the timely responses to events reported by the sensors. However, due to scattered nature of events, mobility of actor nodes, and low density of actor nodes, the network of actor nodes tends to get partitioned frequently. To provide effective AAC in such situations, the energy-constrained sensor nodes located between the partitioned actor nodes need to be utilized. This solution for healing the actor network partitions should involve minimal use of the sensor nodes so that the network lifetime is maximized. In this work, we propose an energy-efficient Actor-Actor Reliable Transport Protocol (A²RT) for WSANs with actor nodes equipped with directional antennas and dual radio interfaces. Our proposed transport protocol consists of a transport wrapper and a dynamic priority scheduler. Using simulations, we show that our transport wrapper achieves high reliability with minimum retransmissions both under static and dynamic network topology conditions. The results also show that the traffic scheduler of our protocol helps to achieve the goals of real-time delivery by maximizing the number of packets that meet the delay constraints.