Time-efficient protocols for neighbor discovery in wireless Ad Hoc networks

Neighbor discovery (ND) is a basic and crucial step for initializing wireless ad hoc networks. A fast, precise, and energy-efficient ND protocol has significant importance to subsequent operations in wireless networks. However, many existing protocols have a high probability of generating idle slots in their neighbor discovering processes, which prolongs the executing duration, thus compromising their performance. In this paper, we propose a novel randomized protocol FRIEND, which is a prehandshaking ND protocol, to initialize synchronous full-duplex wireless ad hoc networks. By introducing a prehandshaking strategy to help each node be aware of activities of its neighborhood, we significantly reduce the probabilities of generating idle slots and collisions. Moreover, with the development of single-channel full-duplex communication technology, we further decrease the processing time needed in FRIEND and construct the first full-duplex ND protocol. Our theoretical analysis proves that FRIEND can decrease the duration of ND by up to 48% in comparison with classical ALOHA-like protocols. In addition, we propose HD-FRIEND for half-duplex networks and variants of FRIEND for multihop and duty-cycled networks. Both theoretical analysis and simulation results show that FRIEND can adapt to various scenarios and significantly decrease the duration of ND.