Performance of Adaptive Control CRE for FTP Traffic Model in Heterogeneous Mobile Network

Heterogeneous networks (HetNet), which are combined with a macrocell and picocell in the same coverage, are promised technique to further increase the system capacity. In HetNet, cell range expansion (CRE) technique using cell selection offset (CSO) can allow more user equipment (UE) to access the picocell, i.e., virtually expand the picocell coverage. To enhance the conventional CRE, we have proposed a personal picocell scheme using an adaptive control CRE technique in which different CSOs are assigned to UE to form each optimal picocell for each UE. In this paper, we show the performance of adaptive control CRE in HetNet composed of a macrocell using a 2 GHz band and picocells with a wide bandwidth using 4.5 GHz band, especially for file transfer protocol (FTP) traffic model. We first describe the principle and connection sequence of the adaptive control CRE. Then, we show the average and 5-percentile user throughput of HetNet using the proposed CRE in comparison with conventional CRE under two types of traffic models, i.e., full buffer and FTP models. From these results, we confirmed that the proposed CRE can improve the 5-percentile user throughput while maintaining the average user throughput compared with that of conventional CRE for both traffic models.