A QoS Opportunistic Routing Based on Directional Transmission for Wireless Sensor Networks

For mission-critical application of WSN, it's essential to guarantee multi-QoS requirements including of delay and reliability as far as possible. The existing multipath routing methods fulfill QoS demands by disseminating the redundant replica over multiple paths, leading to low energy efficiency and higher delay. In this paper, a novel Directional Transmission based QoS-aware Opportunistic Routing, DTQOR is proposed for timely and reliable delivery. At first, by partitioning the end-to-end delay and reliability into each hop on a path, the QoS routing metric subjected to reliability and delay is formulated as a multi-objective multi-constraint optimization problem. Based on the analysis about impact of Directional Transmission on connectivity and constraint relationship of forwarding candidates, an approach is designed to reduce selecting scope of next hop candidate nodes. A heuristic algorithm to construct prioritized permutation of forwarding candidates is further proposed to achieve sufficient suboptimal aim and whole routing mechanism are provided finally. The simulations have been conducted to evaluate the performance of DTQOR through NS-2. The results have demonstrated that the proposed DTQOR reduces the end-to-end delay significantly and improve the energy efficiency.