Robust designs for femtocell networks with interference from macrocell users

Femtocell networking is a promising solution to improve the indoor coverage issue and enhance system throughput for next generation wireless networks. However, one of the main concerns to put through femtocells is the interference issue between macrocell and femtocell networks. In this paper, we consider femtocell uplink transmissions with dynamic interference from macrocell users. Without information exchange or subcarrier reallocation between femtocell and macrocell at any base station, we propose a precoded frequency division multiple access (P-FDMA) transmission with novel detectors to mitigate macrocell-to-femtocell uplink co-channel interference (MFU-CCI). It is shown that our design collects multipath diversity without estimating the interference channels and is robust to MFU-CCI. Simulation results validate our findings.