In-band bootstrapping in database-driven multi-hop cognitive radio networks

Database-driven approach has emerged recently as an alternative or supplement for spectrum sensing for cognitive radio networks (CRNs). Within database-driven CRNs, master devices obtain spectrum information by direct connection to a spectrum database, while slave devices can only access spectrum information indirectly via masters. The in-band approach completely based on primary spectrum channels can be used, which eliminates the need for out-of-band connections and eases the adoption of the database-driven spectrum sharing. In this paper, we study the in-band bootstrapping process for database-driven multi-hop CRNs, where master/slave devices form a multi-hop networks, and slaves need multi-hop communications to obtain spectrum information from the master during bootstrapping. We start with the basic design of in-band bootstrap protocol, whose performance is unsatisfactory of protocol overhead and bootstrap time. Then we propose 2 enhancements: first, we incorporates the recursive fractional spectrum information query scheme to reduce protocol overhead; then we propose the prefetch scheme to reduce the bootstrap time. According to the analysis and simulation results, our proposed protocols can greatly improve the performance: the recursive fractional spectrum information query enhancement reduces up to 40% of the overhead, the prefetch enhancement reduces more than 20% of the bootstrap time.