Reciprocal spectrum sharing game and mechanism in cellular systems with Cognitive Radio users

To fully exploit Cognitive Radio (CR) techniques as secondary transmissions in exiting primary systems (PSs), especially cellular systems, we propose a cooperative spectrum sharing mechanism where CR users serve as relay nodes to enhance PS´s performance, and PS leases some portion of resources for CR users´ networking services by granting them radio access. Moreover, for CR users exposed to multiple licensed wireless service providers (WSPs), a further complicated spectrum sharing market is formed because not only WSPs compete for relay nodes, but also CR users compete for the released resources. We formulate such reciprocal behaviors as a three-tier game and specify the additional configurations of control channel protocol to achieve the game equilibrium, where WSPs and CR users focus on maximizing their own utility functions. The results show a win-win solution that CR users are able to acquire radio access while enhancing PS´s performance, which offers the opportunities and incentive for CR deployments.