Avoidance of Co-tier Interference between Femtocells with Different Access Modes

Deploying Femtocells inside a macrocell network can significantly increase the macrocell capacity in terms of network optimisation. However, the deployment of femtocells within a macrocell coverage area causes severe femto-femto interferences, which may have an impact on the overall performance of femtocells. Avoiding such interference is very important for co-existence of femtocells. In this paper, we propose a novel femtocell resource allocation scheme to alleviate the problem of Co-tier interference. In the proposed scheme orthogonal resources are allocated to the closed access femtocells to avoid interference to other femtocells, while we divide the open access femtocell coverage area into two coverage area, an inner and an outer coverage area. The resources are allocated to both coverage areas of the open access femtocells in a way that avoids co-tier interference while increasing the spectrum efficiency.