Distributed uplink interference control based on resource splitting in heterogeneous cellular networks

Heterogeneous cellular networks that consist of macrocells and small cells can offer significant capacity gain by utilizing the resources of the small cells. However, for this purpose, the interference between the macrocells and the small cells should be carefully managed. In this paper, we propose two types of uplink inter-cell interference control schemes: handover-assisted bandwidth-splitting and quality-of-service (QoS)-aware power-splitting. The bandwidth-splitting interference control scheme is a win–win strategy that enhances the rates of both interfering user and interfered user via handover and frequency partitioning. On the other hand, the power-splitting interference control scheme is a yield-win strategy that enhances the rate of interfered user while reducing the rate of interfering user via message and power partitioning. Each scheme has its own operation region. The bandwidth-splitting scheme can be employed when the interfering user is located in the outer cell region having low signal-to-noise ratio (SNR), whereas the power-splitting scheme can be employed when the interfering user is located in the inner cell region having high SNR. We also propose an operational framework with low feedbacks and computational complexity. Simulation results show that the proposed controls significantly reduce interference while guaranteeing the target user QoS at best; therefore, they provide enhanced rate distribution, average ergodic rate and outage ratio under the typical target rate and range expansion bias, as compared to legacy interference control schemes.