Interference Mitigation and Spectrum Sharing for Heterogeneous Networks Based on CQI Feedbacks

In this paper, we address a cross-tier interference mitigation scheme for heterogeneous networks based on cognitive radio technology, where the femtocell equipments, functioning as the secondary user, share the same frequency resource with the macrocell in the underlay mode. Different from other work, we assume that the femtocell access point (FAP) is able to listen to the quantized cellular channel quality information from the macrocell user equipments (MUEs) in its vicinity, and judiciously selects its own transmission power such that the average femtocell throughput is maximized with tolerable rate loss to the macrocell. We demonstrate the efficacy of the proposed scheme through extensive simulations under three typical scenarios: FAP has macrocell´s scheduling information, FAP does not have this scheduling information but protects MUEs in a statistical fashion and, finally, FAP conservatively utilizes the channel by assuming the activated MUE always exists in its vicinity.