Performance Guaranteed Routing Protocols for Asymmetric Sensor Networks

In this paper, we propose performance guaranteed routing protocols in asymmetric sensor networks (ASNs) where two end nodes may not use the same path to communicate with each other. ASNs can be caused by hardware devices or environment. Different from most of the existing routing protocols in symmetric sensor networks, because of asymmetry, achieving desired routing performance in ASNs poses significant research challenges. To address these challenges, we first propose a general framework protocol called reverse path (RP) to deal with asymmetric links and then present two efficient routing algorithms LayHet and EgyHet built on RP to satisfy performance requirements. LayHet is a performance guaranteed layer-based routing protocol that embeds the shortest path information and saves energy by minimizing the number of broadcasts and the probability of forwarding. EgyHet is its energy-upgraded version that considers nodes' remaining energy. Simulation results comparing the proposed and existing protocols show that LayHet and EgyHet can reach the desired delivery rate earlier than the existing one and outperform it in terms of average hops, average packet replication overhead, and average control message overhead. In addition, as sensor energy reduces, the performance of LayHet and EgyHet eventually degrades more slowly than that of the existing one.