A novel architecture and media access protocol for cognitive radio based autonomous femtocell networks

Femtocell networks are being deployed in homes and offices to extend the services of cellular networks in indoor network environment. In this paper we propose a cognitive radio based autonomous femtocell network architecture that shares the radio spectrum of a 4G macrocell network. The proposed femtocell architecture uses an overlay access mechanism under the presumption of a hierarchical access scenario where femtocell users are secondary users to the shared spectrum. A media access control protocol is proposed for this femtocell network architecture which exploits the time division duplex operation of the uplink and downlink transmissions in macrocell. The performance of the media access control protocol in terms of the available number of frames and the throughput performance of the femtocell network is presented to validate the effectiveness of the proposed femtocell network architecture.