Adaptive Fractional Frequency Reuse (AFFR) scheme for multi-cell IEEE 802.16e systems

In this paper we present a new adaptive fractional frequency reuse scheme (AFFR) for multi-cell OFDMA based IEEE 802.16e network. The adaptive fractional frequency reuse (AFFR) scheme is managed by the access service network gateway (ASN-GW) which coordinate a set of BSs (one cluster). To make better usage of radio resources; we assume that the cell area is virtually divided into two different zones: the fractional frequency reuse (FFR) zone which includes all users who are suffering from high inter-cell interference ICI from neighbouring cells and the full usage (FU) zone where inter-cell interference ICI can be neglected. The base station BS assigns users to each zone dynamically based on their channel state information. ASN-GW decides the set of subcarriers assigned to the FFR zone within each BS. In the FU zone; all subcarriers available in the system can be used. We provide simulation results comparing our AFFR scheme with different schemes. We examine the effect of the choice of the major system design parameters on the performance. The simulation results illustrate the superiority of the proposed scheme for multiple values of system design parameters.