A dynamic downlink load control scheme with virtual coverage adjustments for two-tier LTE systems

Abrupt increase in traffic load can cause traffic overloading situation, thereby degrading the performance of two-tier LTE systems, in which femtocells are overlaid with macrocells. In this paper, we propose a dynamic downlink load control scheme with virtual coverage adjustments for the two-tier LTE system, in which the coverage of hotspot macrocell is virtually controlled by adjusting handover parameters of serving cell and target cell. Simulation results show that our proposed control scheme can effectively prevent traffic overloading, and thus improve the performance of the two-tier LTE system. In particular, with the proposed scheme, the two-tier LTE system can also achieve system stability with the role of femtocells as a load shelter.