Energy Efficiency Optimization in LTE-U Based Small Cell Networks

In this correspondence, an energy efficient (EE) optimization scheme is proposed for the LTE-unlicensed (LTE-U) based small cell networks. The small cell reuses the licensed bands with the macro base station and shares the unlicensed bands with multiple Wi-Fi access points . Therefore, there exists co-channel interference on licensed bands, and the collision on unlicensed bands. To maximize the system EE while guaranteeing the harmonious coexistence with macro cell and Wi-Fi networks, spectrum (both licensed and unlicensed) and power allocation are jointly considered to formulate a non-convex optimization problem. Accordingly, convex approximation and the classic Dinkelbach method are applied to derive the optimal scheme. Based on the proposed scheme, the interaction between the EE on licensed and unlicensed bands are revealed, and the performance of the scheme is verified via the simulation.