User Association for HetNet Small Cell Networks

Heterogeneous networks principally composed of macro-cells overlaid with small cells (e.g., Femtocells, pico-cells, and relays) can potentially improve the coverage and capacity of existing cellular networks and satisfy the growing demands of data throughput. In Het Nets, small cells play a key role in offloading user data traffic from congested macro-cells and extending the limited coverage of macro-cells. However, the use of small cells is still impeded by the issues of coexistence and efficient operation, as small cells are characterized by limited resources, large-scale random deployment, and a lack of coordination. In this paper, we focus on user association problem in Het Net, and we propose a new scheme by applying the Voronoi diagram, a powerful computational geometry technique, to solve the user connection problem in which a user has several stations within his range from which to choose. Simulation results show that our proposed scheme can significantly increase the number of admitted users and system throughput.