Online probabilistic activation control of picocells for system throughput maximization in heterogeneous networks

In this paper, we propose a method for online probabilistic activation/deactivation control of pico-base stations (BSs) in heterogeneous networks where low transmission-power pico-BSs are overlaid onto a high transmission-power macro-BS. By deactivating the signal transmission of unnecessary pico-BSs, the inter-cell interference is reduced resulting in an increase in system throughput and a reduction in energy consumption. We focus on maximizing the system throughput in this investigation. The proposed method does not rely on a priori knowledge of probability distributions of user locations or the traffic load of the entire system coverage, which sets it apart from previous work. Therefore, complicated inter-BS cooperation and measurement at the user terminals are not necessary. This also enables the online control of pico-BS activation/deactivation tracking of the change in user/traffic distribution within the system coverage. The proposed method requires only a single metric to be exchanged among BSs, which is a system throughput measure at each cell. The proposed method adaptively controls the activation probability of each pico-BS individually, depending on the time variation in the system throughput and the temporal activation/deactivation states of each BS. Computer simulation results show the effectiveness of the proposed method compared to the case without activation/deactivation control of the pico-BSs.