Developed Mechanisms for CROSS-TIER and CO-TIER Interference Avoidance in FEMTOCELL NETWORKS

To deal with the increasing demand of high speed data streaming and good quality voice traffic from mobile users at home, Femtocell Networks are deployed in homes that enables an indoor mobile user to achieve high speed downloading from the internet and make good quality voice calls. A femtocell network also provides relief to an overloaded macrocell network by servicing mobile users at home which without the femtocell network have to be served by the macrocell. However, like all wireless networks, femtocell networks suffer from the problem of interference. In this thesis, a contribution to the existing research on the avoidance of interference in femtocell networks is presented. In the first part of the thesis, the “cross-tier interference” caused by a femtocell network operating in “closed access mode” to a macrocell user is investigated. Cognitive Radio is implemented in the Femtocell Base Station (FBS). More specifically, a sensing and transmission scheme is presented that allows a cognitive enabled femtocell to actively sense the macrocell spectrum and allocates vacant resources to its