Abstract
In this paper interference management in co-channel deployment of macrocell and cognitive femtocells is investigated. For the purpose of the aggregate interference mitigation from all femtocell access points (FAP) to macrocell user equipment (MUE) and the purpose to increase the radio link quality of femtocell system, a parameter named interference tolerable threshold (Ith) is introduced, the aim is to reduce the interference an individual FAP causes to MUE to a level lower than Ith. A dynamic Ith control scheme is proposed to determine the appropriate value of this threshold. The simulation results show that the highest available Ith depends on the total number of FAPs, a larger number of FAPs does affect aggregate interference even if the individual interference is in acceptable range. The proposed method, however, achieves the adaptation of the highest available Ith without needing knowledge about the number of FAPs in the vicinity of MUEs.