Date Added: Apr 2011
In this paper, the authors propose an opportunistic Power Control (PC) algorithm to mitigate the AGGregate Interference (AGGI) from active femtocells in uplink transmission. Macrocell Base Station (BS) decides the interference allowance per femtocell and femtocell users then allocate their transmit power within the allowance to suppress the cross-tier interference in heterogeneous networks. The PC algorithm should reflect the number of active femtocells per cluster to effectively control the AGGI, and they propose two sensing algorithms, such as centralized and distributed ones, to estimate the number of active femtocells. They compare the two sensing algorithms in terms of the outage and throughput performance. The algorithms exploit large-scale channel information and shadowing variation to guarantee the macrocell uplink channel quality. Consequently, the two sensing algorithms increase total cell throughput.