Optimal Query-Driven Data Forwarding for Delay-Sensitive Wireless Sensor Networks

Most of existing works on the topic of real-time routing for wireless sensor networks suffer from void forwarding paths (cannot reach the destination, but have to backtrack) and time overhead of handling isolated nodes. Designing a desired real-time data forwarding protocol as well as achieving a good tradeoff between real time and energy efficiency (as well as energy balance) for delay-sensitive wireless sensor networks remains a crucial and challenging issue. In this paper, we propose an optimal query-driven data forwarding framework that each sensor gets its optimal data forwarding paths (directed acyclic graphs) based on the query messages flooded by the base station without extra overhead. Furthermore, First Forwarding Nodes and Second Forwarding Nodes schemes are developed for data forwarding. In addition, two greedy distributed data forwarding algorithms are provided base on hybrid link cost model trying to achieve energy balance and congestion avoidance in data forwarding. Our framework is fully distributed and practical to implement, as well as robust and scalable to topological changes. The extensive simulations show that our framework has significantly outperformed the existing routing protocols in terms of real time and energy efficiency.