TDD cognitive radio femtocell network (CRFN) operation in FDD downlink spectrum

Abstract

Deploying cognitive radio femtocell network \n(CRFN) inside a macrocell network can significantly increase \nthe utilization of the available macrocell bandwidth and \nincrease the capacity of the macrocell. However, the success of \nthis deployment in terms of performance degradation of the \nmacrocell and the acceptable throughput for the CRFN is not \nwell defined. In this paper, we propose a time division duplex \n(TDD) operation of a CRFN and investigate its performance \ninside a macrocell operating in frequency division duplex \n(FDD) mode. It is shown that with a proper sensing and \ntransmission scheme the capacity of the CRFN can be increased \nby simultaneous transmissions on multiple channels, water-filling \nfurther improves the result when interference from the macrocell \nbasestation is large. The proposed scheme is applicable to full \nduplex networks, such as LTE and GSM.