Cooperative interference mitigation in heterogeneous LTE networks

Small cell transmission is a promised technique to enable the tremendous data growth in next generation long term evolution (LTE) networks. However, emerging inter-cell interference is the dominant limiting factor achieving higher network capacities. In this paper we focus on cooperative interference mitigation techniques in interfering heterogeneous network (HetNet) deployments to assist the cell edge user equipment (UE) suffering from dominant co-channel interference (CCI). As a handover might be refused and conventional precoding matrix index (PMI) selection schemes limit reliable downlink (DL) transmission, the co-scheduled UEs being in good channel condition delegate the precoding vector selection to that victim UE. We provide a practical implementation for the cooperative interference mitigation algorithm keeping computational complexity and feedback overhead low. With numerical results at the link level we show that CCI is almost suppressed and as a result near optimum DL performance is achieved at the cell edge UE in strong interfering HetNet deployments.