Topology Discovery Delay Evaluation in Star Topology Network with Switched-Beam Antenna Sink

Abstract

Wireless Sensor Networks (WSNs) are useful in several application domains. They are often used for data gathering in an interested area. The popularity of WSNs is due to their ease of deployment and auto-configuration capabilities. A WSN network is composed by several sensor nodes that must cooperate and build the network where each node is in range of at least one other node. In star network topology, the sink node is in range of the all others and the communication from each node to the sink is assumed to be a single hop. So, the sink node can discover all the others nodes around it belonging to the star topology. In most cases, the network set-up phase begins with a topology discovery. One usual way for the discovery process is to allow each node to broadcast hello messages during a given period of time. When the sink located at the center of the star topology is equipped with a directional antenna, this discovery process has to be done for each beam direction of the sink antenna. In this work we are dealing with a star topology having a sink with a directional switched-beam antenna. In such case, the connectivity between the sink and other nodes is intermittent. In this paper, we present an optimized approach called WAYE that helps to reduce the network discovery time using a sink with a switched-beam antenna. The performance evaluation using Contiki Os Cooja simulator shows that the proposed approach outperforms the IEEE 802.15.4 CSMA/CA algorithm with directional and omni-directional antenna.