Adaptive Control of CRE with Proportional Fair Resource Scheduling in LTE HetNets

Abstract

A heterogeneous network (HetNet) in LTE is typically a combination of macrocells and small cells contributing to meeting the increasing demand for network capacity. Cell range extension (CRE) is the process to extend the area under the small cell in order to balance the loads between the macrocell and the small cell. A cell selection offset (CSO) is added to small cells to set the amount of extension appropriately. An adaptive CSO can better address the continuously changing network conditions than a fixed CSO. While deriving schemes for CSO determination, it is rational to incorporate practical resource scheduling methods as well as to focus on the achievement of good balance in loading, which existing research works are lacking. An adaptation technique of CSO, based on the round robin (RR) resource scheduling, is already demonstrated. However, proportional fair (PF) resource scheduling can be a better choice in a practical network, as it incorporates radio link conditions. In this paper, we propose, based on our formulation, a CSO adaptation method, which can minimize the difference in PF scheduling based loading between the macrocell and the small cell. Then we use simulation results for the demonstration of the effectiveness of the proposed method.