Distributed Forwarder Selection for Beaconless Real-Time Routing in Wireless Sensor Networks

In wireless sensor networks (WSNs), real-time service is one of the important issues. Typically, existing studies for the service are relied on beacons. Recently, beaconless routing has been proposed to overcome control overhead for resource constrained environment of WSNs. Thus, real-time communication based on the beaconless scheme could give great advantages with less energy consumption. To do that, however, it brings new challenges. For the real-time communication, each node needs to be aware of single hop delay for data forwarding within desired time. In conventional approaches, it is based on delay in neighbor information through beacons. An appropriate next forwarder is selected by a sender. However, in the beaconless scheme, a sender could not select a next forwarder since that is determined by a receiver after transmitting data. Also, contention delay is included in single hop delay for beaconless routing. Thus, the delay estimation principle should be renovated. In this paper, we present a receiver-based beaconless routing for real-time services. We design a novel delay estimation strategy. The single hop delay from a sender to a receiver could be calculated by a receiver but not a sender. Therefore, the receiver itself makes a decision whether desired time requirement is satisfied. Simulation experiments show that the strategy achieves higher performance in terms of energy consumption.