Abstract
A protocol named RFGFR (Restricted Flooding and Greedy Forwarding Routing) is presented in this paper. RFGFR propagates query packets from the sink to the centroid of a target region, it employs a scheme of restricted flooding and greedy forwarding results in fewer nodes to forward packets, which means less energy consumption. Greedy forwarding decision can reduce transmission delay by reducing communication hops. Simulations show RFGFR exhibits better performances for object tracking in sensor networks.
Introduction
The main requirements of routing protocols in Object Tracking Sensor Networks (OTSNs) include energy efficiency, reliability, scalability, and real time. Current routing protocols for WSN falls into the following two broad categories according to whether the protocols utilize position information: position-information-based and position-information-free. The position-information-based protocols are applicable to object tracking because of the fact that the queries in OTSNs may often be geographical. A scheme named Restricted Flooding and Greedy Forwarding Routing (RFGFR) is presented in this paper, which is designed for OTSNs. RFGFR is employed to deliver query packets from the sink to an object region (the centroid of this region).
Restricted Flooding and Greedy Forwarding Routing (RFGFR)
Queries about the state of moving objects are often disseminated to the whole network by the sink or another node in OTSNs. Whereas the tracked object is in a specific area, it is unnecessary for the query to be flooded over the entire network. RFGFR employs the scheme of restricted flooding and greedy forwarding, which results in fewer nodes to forward packets, this means less energy consumption. Greedy forwarding decision based on geographical information of an object can reduce the forwarding delay by reducing communication hops. RFGFR is a stateless protocol and fully distributed because it only uses immediate-neighbor information in forwarding decisions, which enhances its scalability. An acknowledgement mechanism between the upstream node and the downstream node enhances the reliability of RFGFR. RFGFR distinguishes various statuses of nodes, and shutdown communication and sensing channel of inactive nodes, this further improves its energy efficiency. Simulations show RFGFR exhibits better performances for object tracking in sensor networks.
Conclusion
Because RFGFR is a reactive protocol, work is required to improve performance of our protocol such as real time, and one of our methods includes adopting location-based multicasting.