A load fairness aware cell association for centralized heterogeneous networks

Load balancing (LB) is important in heterogeneous networks (HetNet). This paper investigates effective cell association schemes for LB. Considering the centralized cellular network architecture with Super Base Stations (SBS), a centralized cell association scheme is proposed, where the calculations are all performed in the SBS and information exchange within the SBS is convenient. There is also no need for the users to feed back information. Thus the signaling overhead is reduced a lot. Moreover, to alleviate the sensitiveness to load changes, the load fairness index (LFI) is defined. The proposed scheme is not performed until the LFI is lower than a given threshold. It is verified by simulations that the proposed centralized cell association scheme can adjust the cell-specific bias according to the cell load and provide better geometry mean rate (GMR) and outage probability (OP) over the comparing schemes. Moreover, with the introduction of LFI, the number of LB performed can be effectively reduced with a lower LFI threshold, however, the system performance such as GMR and OP also degrades. Therefore, an appropriate LFI threshold is needed to balance the system performance and complexity.