Practical Neighbor Discovery in Multi-carrier Ad Hoc Networks with Directional Antennas

Abstract

Neighbor discovery is a crucial step to establish links among the nodes in ad hoc network. Most existing researches on neighbor discovery are based on 1-way or 2-way handshake mechanism in single-carrier system, where nodes send 1-way or 2-way messages without getting acknowledgement from their neighbors. However, when the node scale becomes huge, the 1-way and 2-way handshake algorithms may increase the collision probability, which leads to a huge discovery time. In this paper, considering the multi-carrier system, we proposed a Multi-Hop Algorithm (MHA) to discover all the nodes using multiple 3-way handshake when the number of nodes is unknown beforehand. It can be applied in both the multi-hop and 1-hop scenario. Besides, the upper and lower bounds of the expected time to discover all the nodes are deduced. When there are four carriers in the system, the gap between the expected time and upper and lower bounds are only about 8.48% and 7.66%, respectively. It means that the theoretical bounds can serve as the effective guidance for the expected time. Through extensive simulations, we demonstrate that MHA can significantly decrease the expected time with the help of multi-carrier.