Evaluation of the Reliable Data Transmission Protocol in Wireless Sensor-Actuator Networks

In a wireless sensor-actuator network (WSAN) sensor nodes gather information on the physical world and can deliver messages with sensed values to only nearby nodes due to weak radio. Thus, messages sent by nodes might be lost due to not only collision but also noise. Messages are forwarded by sensor nodes to an actuator node. In the redundant data transmission (RT) protocol, a sensor node sends a message with not only its sensed value but also sensed values received from other sensor nodes. Even if a message with a sensed value v is lost, an actuator node can take the value v from a message sent by another sensor node. We evaluate the RT protocol in terms of how many number of sensed values an actuator node can receive in presence of message loss. We show that about 72 % of sensed values can be delivered to an actuator node even if 95 % of messages are lost due to noise and collision.