Spectrum Allocation with Guaranteed Rendezvous in Asynchronous Cognitive Radio Networks for Internet of Things

The massive usage of Internet-of-Things devices in various smart applications enables spectrum scarcity issues. In order to enhance the dynamic spectrum capability, cognitive radio network (CRN) is considered as a key technology to address the spectrum scarcity problem. However, the establishment of a common communication channel in CRN by considering the unlicensed heterogeneous devices in an asynchronous environment is a challenging problem. In this paper, a novel asymmetric asynchronous channel hopping mechanism is designed, where secondary users have different sets of available channels and can enter into the network without any global clock synchronization. The proposed algorithms can guarantee the rendezvous within a small interval of time with minimum inter rendezvous intervals. Simulation results show that the designed protocol outperforms over the existing channel hopping algorithms in terms of the degree of rendezvous, average time to rendezvous and throughput.