Byunghan Ryu

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In this paper, we evaluate handover (HO) performance when user equipment (UE) moves between femto cell and macro cell in long term evolution (LTE) systems. The focus is on the HO performance for inbound and outbound mobility which corresponds to handoff between the femtocell and the macro cell. Due to the severe signal-to-interference noise ratio (SINR)(More)
The femtocell access point of LTE-Advanced system, which can be deployed under macrocell coverage, was applied to the paper. The paper consists of two analyses which are the interference impact by the femtocell and the macrocell at a user equipment and the load impact to the control plane in evolved packet core network by X2 and S1 handover signaling(More)
Femtocells are usually deployed in an indoor environment to provide in-building coverage enhancements. However, femtocells get to provide services for not only indoor users but also outdoor users in vicinity. Without the knowledge from the femtocell of whether the serviced users are located indoor or outdoor, the outdoor users are likely to experience low(More)
This paper deals with a call admission control method for hybrid mode femtocell base stations. Femtocell base station is a small scale base station which is used for home, office and apartment. On the hybrid access mode, the femtocell base station allows cell entrance for both member subscribers and non-member subscribers. Originally, the base station was(More)
Since random early detection (RED) was proposed in 1993, many active queue management (AQM) algorithms have been proposed to support better end-to-end Transmission Control Protocol (TCP) congestion control. In this article, the authors introduce and analyze a feedback control model of the TCP/AQM dynamics. Then they suggest the concept of an AQM algorithm(More)
A small cell is one of key factors in a Long Term Evolution (LTE) and LTE-Advanced (LTE-A) system. its handover signaling load impact on the evolved packet core (EPC) network is a big issue when considering a benefit and efficiency of S1 and X2 handover (HO) in diverse handover scenarios due to tons of small cells. Therefore, the performance of the inbound(More)