Maximization of the User Association of a Low-Power Tier Deploying Biased User Association Scheme in 5G Multi-Tier Heterogeneous Network

In evolving 5G multi-tier networks, traditional user association schemes, e.g., received power-based user association, become inefficient to ensure better coverage. As it has high transmission power, it will overload the high-power tier such as macrocell. Therefore, a convenient cell-range extension scheme known as biased user association is introduced in which low-power base stations of a multi-tier network are designated with a bias power to expand the coverage artificially, and user equipment communicates with the highest power base station weighed by its bias power. In addition, this paper introduces a novel three-tier heterogeneous network, which consists of macro, pico, and femto cell tiers of base stations. This study, therefore, targeted maximizing the user association for a low-power tier of a multi-tier heterogeneous network utilizing a biased power user association scheme. In addition to the mathematical modeling and analysis of the proposed study, we provide MATLAB simulation results.