This paper shows how to improve the overall network performance (cell throughput, fairness, and energy efficiency) via centralized coordination of LTE-A cells. We first present optimization models for small-scale coordination (i.e., three cells). Then, we show that extending the same solution to a higher number of cells is generally unfeasible, due to both an unfeasible amount of reporting on the UE side, and too high computational requirements. To overcome this limitation we then propose a layered solution which i) relies on small-scale coordination at the first level (e.g., three cells at the same site), and ii) coordinates groups of coordinated cells at a higher scale (i.e., tens of cells), using optimization models, reaping the benefits of a centralized architecture. We show through packet-level simulations that our scheme brings significant benefits, in terms of fairness, throughput, and energy efficiency.

Keywords: {LTE-Advanced, C-RAN, CoMP, Optimization, Cell Coordination}

File: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6934854