Real-time message transmission over wireless sensor and actor networks

Wireless sensor and actuator networks (WSANs) have been more and more widely used in the factory environment, which requires real-time communications. This paper proposes a real-time message transmission protocol on WSANs. The proposed protocol finds the smallest-delay path from a source and the nearest actuator before packet transmission. After that, data packets are transmitted periodically along the path to the actuator until finishing its message transmission session. The protocol uses an RSSI-based restricted flooding to reduce the number of broadcast messages when it finds the smallest-delay path. The performance of the proposed protocol has been evaluated using QualNet simulator and compared with the existing protocol AODV. The simulation results show that the proposed protocol has a better performance than AODV in the protocol overhead, the packet reception ratio, and the end-to-end delay.