An Iterative Water-Filling Based Resource Allocation Scheme in OFDMA Systems for Energy Efficiency Optimization

In this paper, the subcarrier and power allocation problem for energy efficiency maximization is addressed, which is different from traditional throughout maximization. Lagrangian dual decomposition (LDD) is applied in this problem and a multilevel water-filling for power allocation is derived. But the water-filling in this paper is a transcendental equation, which is different from traditional water-filling form. To solve this equation, fixed point iteration is applied. Besides, a sufficient condition for the existence of the fixed point is derived and joint resource allocation algorithms are designed. Finally, numerical results verify our work and the energy efficiency is improved compared with the capacity maximization scheme.