Proportional Fair-Based Joint Optimization of Cell Association and Inter-Cell Interference Coordination for Heterogeneous Networks

This paper proposes a proportional fair-based joint optimization method for cell association and the bandwidth ratio of protected radio resources exclusively used by pico base stations (BSs) for inter-cell interference coordination (ICIC) in heterogeneous networks where low transmission-power pico BSs overlay onto a high transmission-power macro BS. The proposed method employs an iterative algorithm, in which the cell association for a given bandwidth ratio of protected radio resources and the bandwidth ratio control of protected radio resources for a given cell association are alternately repeated for convergence. For cell association, we use our previously reported decentralized iterative cell association method based on the feedback information of each individual user assisted by a small amount of broadcast information from the respective BSs. Based on numerical results, we show that the proposed method adaptively achieves optimal cell association and bandwidth ratio control of protected radio resources, which maximizes the geometric mean user throughput within the macrocell coverage area. The system throughput for the proposed method is compared to that for conventional approaches to show the performance gain.