| Cognitive radio technology is a promising solution to the dilemma between the ever-increasing spectrum demand brought by the booming growth of wireless services and the exhaustion of available spectrum. Multi-hop cognitive radio networks have also been widely accepted as an indispensable component of next-generation communication systems to improve spectrum utilization and to facilitate ubiquitous network access from anywhere at any time. Although offering significant benefits, they also provide unique research challenges over other wireless networks. Of note are the issues associated with the architecture, modeling and design of spectrum management in multi-hop cognitive radio networks.;In this dissertation, we aim to address these challenging and fundamental issues in multi-hop cognitive radio networks, cognitive vehicular ad hoc networks, spectrum auction mechanisms, and spectrum trading systems. Our contributions are mainly sixfold. First, due to the unpredictable activities of the primary users, we propose metrics to evaluate the potential loss for opportunistic spectrum accessing. Second, considering uncertain spectrum supply, we propose a novel architecture of CRNs for spectrum harvesting and sharing, and presented a theoretical study on the joint frequency scheduling and routing problem in multi-hop CRNs. Third, we have a comprehensive study on the path selection problem considering multiple factors including the price of the bands, budget constraints of CR source, link scheduling constraints, flow routing constraints, and activities of primary services. Fourth, under the proposed network architecture, we extend the per-user based spectrum trading into session based spectrum trading, which effectively simplifies the design of spectrum trading systems. Fifth, with a joint consideration of cooperative communications, we propose a cooperative communication aware link scheduling scheme to maximize the throughput for a session in cognitive vehicular ad hoc networks. Last, we incorporate cryptographic technique into the spectrum auction design, and propose a secure spectrum auction scheme leveraging Paillier cryptosystem to purge all the back-room dealings. |
