Performance Evaluation of Neighbor Discovery Algorithms in a Star WSN: Switched beam antenna vs omnidirectional antenna at the Sink

One of the key element in performance measurement for a neighbor discovery algorithm with switched beam antennas is how long it takes to discover the neighbors given that nodes do not have any prior knowledge about their neighbors. An impression we may have in neighbor discovery is that algorithms based on directional antennas takes longer time for a node to discover all its neighbors than those entirely based on omnidirectional antennas. We propose two neighbor discovery schemes, one is based on time slotting and the other on the well known CSMA/CA unslotted version. We evaluate the time that the sink needs to discover its neighbors when it is equipped with a switched beam antenna, and when it uses an omnidirectional antenna. Through our simulation results, we show that when neighbor discovery algorithms based on directional antennas are correctly designed, they achieve the same order of performance in terms of time needed by the sink to discover all its neighbors as those based on omnidirectional antennas. Our simulation results also show that when using a switched beam antenna and CSMA/CA algorithm for medium access at the sink, the discovery delay is higher.