An optimized cooperative transmission scheme for interference mitigation in heterogeneous downlink network

In the context of out-of-cell interference mitigation, cooperative base-station transmission strategy in homogeneous network deployment has been intensively investigated and also been demonstrated effectively. To tackle the problem of interference cancelation in a hierarchical cell structure, this paper proposes a framework for the study of cooperative basestation transmission strategy over macro and femto base stations within the heterogeneous network deployment. In particular, we consider two distinct coordinated schemes for cell median and edge users respectively. The main contribution of this paper is a network-wide optimized transmission scheme in terms of per cell sum rate maximization. Numerical results show that with the proposed cooperative transmission scheme, higher throughput is achieved by both cell median and edge users when compared to the conventional transmission strategy without coordination for inter-cell interference mitigation.