Power Allocation for Energy Efficiency Optimization in Distributed Antenna Systems

An energy efficiency (EE) maximization problem with multiple distributed antennas is considered in this paper. Besides the constraint on the total transmit power and per-antenna transmit power constraints, an additional constraint dealing with total weighted power is introduced. Moreover, a Quality-of-Service (QoS) constraint is introduced. Because the original problem is a fractional convex one, Dinkelbach's algorithm is implemented to reformulate the problem. By investigating the Karush- Kuhn- Tucker (KKT) conditions, the mathematical properties of the globally optimal solution are studied and proved, which provides a deeper understanding of the structure of power allocation among antennas. Numerical results demonstrate the effect of QoS on EE and also the structure of power allocation.