Title: Spectral-Energy Efficiency Optimization for Downlink LTE Advanced with Femto Cells
Speaker: Chang-Ching Hsu
Abstract: The spectrum-energy efficiency metric intends to evaluate profitability for operators, for whom expenditure arises from spectrum and energy use, and revenues come from offering data services; high operational efficiency brings a high profit. It is becoming even unfavorable as more BSs are deployed to cope with increasing data traffics, from which the energy consumption of communication networks is contributed. Literatures have pointed out heterogeneous networks are the key network architecture which opens up the possibilities of increasing the total system capacity and reducing the power consumption significantly for efficient communication technologies. It is noteworthy that the potential for maximizing the profit has not been exploited deliberately with the deployment of femtocells. It is therefore crucial to pursue optimal policies of the heterogeneous environment. This paper investigates the spectrum-energy efficiency improvement potential of exploiting cell size zooming, user migration and sleep mode on the downlink of LTE Advanced cellular communication systems. We formulate the optimization problem as a MILP problem. Then as the complexity of the optimal scheme is unacceptably high, a sub-optimal approach with a lower computational complexity is also proposed. Numerical analysis through case studies demonstrates efficiency improvements, and comparisons between near-optimal solutions against optimality.”