Personal-Cell Scheme Using Adaptive Control CRE for Multicarrier HetNets

Heterogeneous networks (HetNets) that uses multiple carrier frequencies are expected to further increase the system capacity in fifth-generation mobile systems and beyond. In multicarrier HetNets, the cell range expansion (CRE) technique is important and virtually expands the picocell coverage. This paper proposes a personal-cell scheme using an adaptive control CRE to improve the system user throughput in multicarrier HetNets. Adaptive control CRE can provide an optimal personal cell for each user equipment by applying different cell-selection offsets (CSOs) in CRE. The concepts and algorithms of the personal cell scheme that uses adaptive control CRE are described in comparison with the conventional CRE method. We first discuss methods of optimizing the combination of two different CSOs for adaptive control CRE in multicarrier HetNets using carrier frequencies of 2.0 and 3.4 GHz. By using the optimized combination of two different CSOs for adaptive control CRE, we then describe the average and 5-percentile user throughput of adaptive control CRE in comparison with the conventional CRE method. We confirm that the personal-cell scheme that uses adaptive control CRE can improve the 5-percentile user throughput while maintaining the average user throughput. This result provides a remarkably effective solution for multicarrier HetNets.