Self-Optimizing Strategies for Interference Coordination in OFDMA Networks

This paper investigates self-optimizing schemes for interference management in downlink of Orthogonal Frequency-Division Multiple Access (OFDMA) networks: power control, fractional frequency reuse and dynamic fractional load. While the first two schemes are based on continuous power control, the third scheme is based on switching off frequency sub-bands thus dynamically varying the cell capacity and creating frequency reuse patterns. Distributed solutions based on the distributed gradient descent method are developed. Coordination between enhanced eNodeBs (eNBs) is achieved via information exchanged on the X2 interface. The scheduling gain for a Raleigh-fading channel is modeled and incorporated in the solution. Numerical simulations of a large scale Long Term Evolution (LTE) network show the potential benefits of the self-optimization schemes, with significant performance gains brought by the dynamic fractional reuse scheme.