Improvement of Carrier to Interference plus Noise Ratio in WiMAX Networks Using Femtocell Base Station Concept

A Femtocell is a small cellular base station; the concept of deploying femtocells over macrocell has recently attracted growing interests in academia, industry, and standardization forums. Various technical challenges towards mass deployment of femtocells have been addressed in recent literature. Interference mitigation between neighboring femtocells and between the femtocell and macrocell is considered to be one of the major challenges in femtocell networks because femtocells share the same licensed frequency spectrum with macrocell. In this paper, we focus on how received signal quality can be improved by deploying femtocell base stations in a WiMAX system. We propose a Femtocell model to analyze the potential improvement on the CINR (carrier to interference plus noise ratio) when using different channel assignment schemes and different deployment densities of femtocell base stations within a macro cell. CINR can be enhanced when large number of femtocell base station is deployed within macro cells. Least-Interfered-First (LIF) femtocell channel assignment scheme is used to measure the lowest interfering signal level. This scheme can reduce co-channel interference induced by neighboring femtocell base stations in turn showing the improvement in CINR.