A heterogeneous network (HetNet) based on the long-term evolution advanced standard has been developed to improve the system performance; in this HetNet, macrocells and low-power nodes, such as picocells, coexist. Further, cell range expansion has been introduced to encourage data offloading in a HetNet. In this paper, we propose a cell selection scheme based on the signal-to-interference-plus-noise ratio to achieve an optimal offloading effect. We also propose a resource allocation scheme in the frequency and time domains, to reduce interference in a HetNet. In the frequency domain, the macrocells allocate a frequency band by using soft frequency reuse, and the picocells choose the sub-bands that are not used in the macrocell sector, to avoid interference. In addition, we found that it was difficult to allocate a limited frequency resource. Therefore, the cross-tier interference can be managed by using an almost blank subframe (ABS) with a flexible ABS ratio, to improve spectrum efficiency in the time domain. The simulation results show that the proposed schemes can improve the spectrum efficiency of both the macro-user equipment and the pico-user equipment, as well as improve the overall UE performance.
- Cell selection