Multi-layer soft frequency reuse scheme for 5G heterogeneous cellular networks

Heterogeneous network (HetNet) is a promising cell deployment technique where low power access points are deployed overlaid on a macrocell system. It attains high throughput by intelligently reusing spectrum, and brings a trade-off between energy- and spectral-efficiency. An efficient resource allocation strategy is required to significantly improve its throughput in a bid to meet the fifth-generation (5G) high data rate requirements. In this correspondence, a new resource allocation scheme for HetNet, called multi-level soft frequency reuse for HetNet (ML-SFR HetNet), is proposed which increases the throughput several fold. In ML-SFR HetNet, mutually exclusive spectrum is allocated for macro and small cell users and well as for cell edge users among the various cells in the reuse system. We derived spectrum and power allocation expression for a generalized HetNet scenario. In addition, analytical expressions for the throughput and area spectral efficiency (ASE) are also developed. The simulations results demonstrates the efficiency of the proposed scheme which improves the throughput by around 3.5 times and outage probability reduces nearly 5 times compared to traditional SFR system.