Link Rendezvous Protocol for Cognitive Radio Networks

In an opportunistic dynamic spectrum access environment, individual nodes sense the local spectrum and choose their operating frequencies and bandwidth in collaboration with the other participating nodes. To make their spectrum access decisions, the nodes need to communicate with the existing nodes operating in the area. In this paper we propose an approach which establishes this first connection with a minimum risk of interference. We propose a link rendezvous strategy which relies on frequency domain decision statistics. Nodes wishing to join the network are emitting and scanning for a simple carrier with a small number of sidetones. We describe the strategy in the context of collaborative spectrum sensing. To validate our approach, we describe a series of experiments using the GNU Radio software defined radio toolkit. We show that an attention signal of length equivalent to a single FFT frame can be detected in a high noise environment using two sidetones.