A capacity degradation model under interferences for sectorized cellular networks with fractional frequency reuse

This paper presents a capacity degradation model under interferences for sectorized cellular networks with fractional frequency reuse. In a sectorized fractional frequency reuse network, allocated bandwidth consists of a number of frequency partitions. To avoid intra-cell interferences, each frequency partition is then assigned to two different groups, the super group (Sup-G) and the regular group. However, because a Sup-G in a cell employs the same frequency partition as the other Sup-Gs in the neighboring cells, inter-cell interferences may become serious when the radius of the Sup-G is largely increased. In the worse case, the largely increasing inter-cell interferences will eventually degrade the overall system capacity. Additionally, different density distributions of mobile stations may have different levels of impact on the capacity degradation. In this paper, both folded normal distribution and uniform distribution are considered in building the capacity degradation model. Numerical simulations show that by carefully adjusting the ratio between the radius of the Sup-G and the radius of a cell, (i) an mobile station could receive the same capacity no matter where it is residing, and (ii) the maximum system capacity can be therefore achieved. Copyright © 2013 John Wiley & Sons, Ltd.