Cooperative spectrum sensing for green cognitive femtocell network

Data traffic demand in cellular networks continues to increase exponentially leading to high capital expenditure and operational costs such as electricity cost. Femtocells have been proposed as a solution to enhance network capacity without significantly increasing energy consumption and associated network deployment costs. In this paper, we analyze the network capacity and energy consumption aspects of a joint macrocell and femtocell network based on the LTE standard. Femtocells and macrocells are operated in the same frequency band to enhance spectral efficiency. Femtocell users are secondary users who only access the channel opportunistically when macrocell users are idle. We propose the use of cooperative spectrum sensing to manage adverse interference emanating from the co-channel operation of both macrocells and femtocells. Simulation results show that cooperative sensing is very effective at managing this cross-tier interference to maximize the throughput of both the macrocell and femtocell layers. This throughput maximization allows the lowest energy consumption ratio of such a heterogeneous network.