An improved incremental frequency reuse scheme employing maximally orthogonal fundamental segments

We propose an efficient segment assignment strategy for the incremental frequency reuse (IFR) scheme, in which each cell within a cluster of adjoining cells has its own fundamental segment orthogonal to a maximal extent to those of other cells within the cluster, in order to control effectively inter-cell interference (ICI). First, the IFR scheme with maximally orthogonal fundamental segments (MOFS) (hereafter, called as the IFR-MOFS scheme) divides the entire radio spectrum into multiple segments, in which all the cells within the cluster follow the same segmentation rule. Then, it designates a unique MOFS for each cell, distinct from those of other cells within the cluster. Finally, a set of corresponding segment assignment sequences is defined to mitigate ICI within the cluster greatly through systematic segment allocation among adjoining cells. A system-level simulator for an orthogonal frequency division multiple access (OFDMA) cellular system covering surrounding cells up to 3^rd-tier has been implemented. Simulation results show that the IFR-MOFS scheme provides quite bett er the cell-edge performance as well as the overall cell capacity a s compared with the original IFR scheme, the soft frequency reuse (SFR) scheme, and the classical universal frequency reuse (UFR) scheme.