Abstract
Energy efficiency (EE) has become a critical metric for the next generation mobile networks. Scheduling plays a key role for offering not only spectral efficient but also energy efficient operation in mobile networks. In this paper, we address the problem of EE scheduling for the downlink of a two-tier Heterogeneous Network (HetNet) with orthogonal frequency division multiple access (OFDMA). Contrary to the existing contributions on this research topic, we propose a coordinated green scheduling scheme that maximizes EE for the entire HetNet rather than a particular tier. Moreover, our novel scheduling scheme uses a more realistic EE criterion where the time dependence of the scheduling process is taken into account. Numerical results are presented showing the competitive EE performance of our proposed scheduling scheme with improved user fairness and reduced complexity compared with existing non-HetNet schemes. In dense small cell situation, our scheme reduces the scheduling processing time as much as 25 times.