Optimizing the Spectrum and Energy Efficiency in Dynamic Licensed Shared Access Systems

In the licensed shared access (LSA) spectrum-sharing scheme, the protection of the incumbent leads to degradation in the licensee's spectrum and energy efficiency. In this paper, the optimization of these two performance metrics for an LSA vertical sharing between an airport incumbent and a mobile network licensee during the period when the LSA spectrum is not available,(ie, the incumbent is active) is examined. Considering a restriction zone of a predefined radius, a power allocation scheme for joint optimization of the energy and spectrum efficiency during the period of the incumbent's occupation of the LSA band is formulated. Specifically, for the joint optimization of the spectrum and energy efficiency, the weighted sum approach to solve the ensuing multi-objective optimization problem is adopted. Furthermore, various critical operational parameters in conjunction with the two performance metrics were investigated. The results obtained show that, with the proper selection of cell radius, eNodeB transmit power and user number per cell, the proposed system can simultaneously achieve the trade-off objective of improved spectrum and energy efficiency.