A novel traffic-adaptive spectrum leasing scheme between primary and secondary networks

Spectrum leasing has been widely regarded as one of the most effective ways to improve the utilization of limited spectrum resources. The existing literatures normally regulate secondary users (SUs) to lease unused licensed spectrum from primary users (PUs) for indefinite or predetermined time length, which does not adapt to real-time traffic demands of SUs and may limit the utilization of licensed spectrum channels. In view of this, the present paper proposes a novel traffic-adaptive spectrum leasing scheme, which allows PUs and SUs to negotiate leasing periods with variable time length such that SUs can continuously utilize the leasing channels for transmitting dynamically generated secondary packets until their transmission buffers become empty. Following this scheme, we further formulate the utilities of both PUs and SUs in traffic-adaptive spectrum leasing based on M/M/k queues and derive the unique sub-game perfect equilibrium of this scheme based on the Stackelberg game model. Numerical simulation shows that, compared with the existing spectrum leasing schemes based on cooperative relaying, the proposed scheme can concurrently afford both PN and SN with higher leasing utilities, encourage them to join spectrum leasing, and achieve a better utilization of limited spectrum resources.