User Classifying-Based Hybrid Spectrum Allocation in Two-Tier OFDMA Femtocell Networks

This paper addresses the cross-tier interference issue in two-tier OFDMA femtocell networks using hybrid spectrum allocation. Firstly, we propose a classification method for users. The macro users are classified into several categories based on their geographic location, and femto users are classified according to the categories of macro users. Then, based on such user classifications, a hybrid spectrum allocation (HSA) scheme is proposed. HSA employs a dynamic orthogonal spectrum allocation for macro user categories according to the number of MUEs in two-tier networks, and fractional spectrum reuse for femto user categories based on their different communication environments. Simulation results show that the proposed scheme can improve outage and throughput performance of macro users with less impact on femto users.