Dynamic fractional frequency reuse based hybrid resource management for femtocell networks

Femtocell access points are inexpensive, plug and play home base stations designed to extend radio coverage and increase capacity within indoor environments. Their inherent uncoordinated and overlaid deployment however, means existing radio resource management (RRM) techniques are often ineffectual. Recent advances in dynamic RRM have emphasised the need for more efficient resource management strategies. While centralised resource management offers improved coordination and operator control giving better interference management, it is not scalable for increasing nodes. Distributed management techniques in contrast, do afford scaled deployment, but at higher node densities incur performance degradation in both system throughput and link-quality because of poor coordination. The level of spectrum sharing mandated by macro-femto deployment also impacts on system throughput and is scenario dependant. This paper presents a new hybrid resource management algorithm( HRMA) for down-links in orthogonal frequency division multiple access-based systems, with the model analysed for a range of macro-femto deployment scenarios. HRMA employs a dynamic fractional frequency reuse scheme for macro-cell deployment with frequency reuse defined for femto users depending on their location by making certain frequencies locally available based on macro-femto tier information sharing and efficient localised spectrum utilisation. Quantitative performance results confirm the efficacy of the HRMA strategy for various key system metrics including interference minimisation, outage probability and throughput.