An efficient interference mitigation approach via quasi-access in two-tier macro-femto heterogeneous networks

Two-tier heterogeneous networks, where the current cellular networks, that is, macrocells, are overlapped with a large number of randomly distributed femtocells, can potentially bring significant bene fits to spectral utilization and system capacity. In a two-tier network, the cross-tier interference needs to be handled properly. Unlike the downlink interference, the uplink (UL) interference at femtocell caused by macrocell user equipment (MUE) has not been addressed sufficiently. When an MUE is located near the coverage of femtocell, its transmit power may cause UL interference to the femtocell receiver, especially for the closed subscriber group femtocells that share the entire frequency spectrum with macrocell. We propose a novel quasi-access strategy, which allows the interfering MUE to connect with the interfered femtocell access point (FAP) while only via UL. It can significantly alleviate the UL interference at the FAP as well as its neighbors, in the meantime, benefit the macro-tier.