“…It divides each macrocell into an inner and outer area, with the latter being further sub-divided into multiple sectors. In dynamic FFR [25], the number of channels available in each sector varies dynamically in proportion to the number of user in the area, with the femto layer being subsequently updated about any changes on a regular interval. Each colour in Figure 2 represents an available spectrum band for the macrocell users in that area, with femtocells being prohibited from using these frequencies.…”