Energy-Efficient Adaptive Geosource Multicast Routing for Wireless Sensor Networks

We propose an energy-efficient adaptive geosource multicast routing (EAGER) for WSNs. It addresses the energy and scalability issues of previous location based stateless multicast protocols in WSNs. EAGER is a novel stateless multicast protocol that optimizes location-based and source-based multicast approaches in various ways. First, it uses the receiver's geographic location information to save the cost of building a multicast tree. The information can be obtained during the receiver's membership establishment stage without flooding. Second, it reduces packet overhead, and in turn, energy usage by encoding with a small sized node ID instead of potentially large bytes of location information and by dynamically using branch geographic information for common source routing path segments. Third, it decreases computation overhead at each forwarding node by determining the multicast routing paths at a multicast node (or rendezvous point (RP)). Our extensive simulation results validate that EAGER outperforms existing stateless multicast protocols in computation time, packet overhead, and energy consumption while maintaining the advantages of stateless protocols. 1. Introduction Large self-organizing wireless sensor networks (WSNs) consist of a great number of sensor nodes with wireless communication and sensing capabilities. The sensor nodes can be deployed randomly close to or inside of the terrain of interest to provide cooperative wireless ad hoc network services. The sensed data and control messages are exchanged between sensor nodes and the control (sink) nodes via a multihop routing protocol. Potential applications of WSNs are numerous, and include environmental monitoring, industrial control and monitoring, and military surveillance to name a few. Many sensor nodes have been commercially developed for various purposes (e.g., [1–6]). However, the sensor nodes have limitations such as a low capacity processor, small memory, and tiny storage as shown in Table 1, in addition to battery constraints. Table 1: Capacities of sensor nodes. Meanwhile, many WSN applications such as mission assignments, configuration updates, and phenomenon reports require one-to-many communications in nature, either from a sensor node to sink nodes or a sink node to sensor nodes. Multicast routing is an important routing service for such applications, as it provides an efficient means of distributing data to multiple recipients compared to multiple unicasts, using in-network replication. Considering both limitations of sensor nodes and the significance of multicast routing, it