Statistical QoS Guarantees for Energy Harvesting Cognitive Radio Networks

Spectrum and energy resources are very important for the rapidly developing of the fifth generation (5G) wireless communication networks. Cognitive radio and energy harvesting technologies, which focus on the spectrum efficiency and the energy efficiency, respectively, can be jointly used for solving the scarcities of spectrum and energy in energy harvesting cognitive radio networks (EHCRNs), where the energy is absorbed from ambient space and spectrum is licensed to the primary users. However, how to guarantee the quality of service (QoS) for EHCRNs is still a challenging problem. In this paper, we develop the optimal power and rate adaptation scheme under statistical QoS provisioning for EHCRNs. In particular, we analyze the power constraints of EHCRNs. Then, we formulate the effective capacity maximization problem for EHCRNs, solving which we obtain the closed-form of the optimal power allocation and rate adaptation scheme under different power constraints. Numerical analyses verify the effective capacity enhancement and validate the relationships among the effective capacity, the QoS exponent, the energy arrival rate, and the average interference power.