A controlled loss transport service for sensor data transmission

A transport service for the transmission of sensor data over a mobile wireless mesh network in tactical scenarios has to cope with both, the requirements of the type of sensor data as well as with the constrained resources and the lossy nature of the wireless network including temporary route disruptions due to node mobility. A fully reliable transport service usually is not feasible in this setup as it increases the network load with frequent packet retransmissions and also leads to large delays of the time-critical sensor data. Instead of using a completely unreliable service like UDP, though, it is desirable to have a semi-reliable transport service offering a sufficient reduction of packet loss while at the same time not overloading the network or leading to excessive delay. In this paper, we present two mechanisms for such a controlled loss transport service. The first concept allows for limiting the number of retransmission attempts for each packet while the second mechanism offers to explicitly restrict the packet loss experienced at the receiver to a maximum percentage. We integrated these mechanisms in our existing Sensor data Transmission and Management Protocol (STMP). STMP provides a flexible transport framework for the transmission of sensor data and the on-line configuration of sensors in various types of networks. In our scenarios we focus on mobile wireless mesh networks in typical tactical scenarios. We evaluated the implemented mechanisms against a reliable and an unreliable service under the impact of different loss probabilities considering aspects like generated network load, timeliness of received packets, and residual packet loss experienced at the receiver.