Sook-Yang Kang

An Enhanced Handover Scheme to Provide the Robust and Efficient Inter-Beam Mobility

This letter proposes an enhanced inter-beam handover (IBH) scheme for millimeter-wave mobile communication systems. The proposed scheme adopts an inter-beam coordinated scheduling to improve the performance of the IBH which can be seriously deteriorated. In addition, the proposed scheme exploits the small-sized low layer messages to reduce the signaling overhead for the IBH by considering the main features of the IBH. Numerical results have shown that the proposed scheme can decrease the handover failure rate and reduce the signaling overhead by 78%~92% compared with the conventional scheme.

An efficient multi-dimensional handover scheme for next-generation networks

In next-generation mobile networks, consisting of multiple heterogeneous wireless networks, the vertical handover procedure is a difficult but important task. In the vertical handover procedure, the methods on which and how handover triggering factors are considered are not standardized. There are many research results considering a single or multiple handover triggering factors, but most of them select the handover network considering multiple factors at the same level. In this paper, we propose a new vertical handover architecture which considers multiple handover triggering factors with multi-dimension. The multiple handover triggering factors are classified and normalized according to their characteristics. The proposed scheme can be easily implemented in real systems because each part of the proposed architecture can be mapped to the corresponding protocol layer. We evaluate the performance of the multi-dimensional architecture using simulations. The simulation results show that our scheme can provide more throughputs with less end-to-end delay compared to other schemes.

Provision of User-Centric Mobile Services in Next Generation Mobile Communication Environment

In next generation (NG) mobile communication environment, it is expected that mobile services will be user- centric and the mobile service platform will play an important role in supporting various future mobile services not only for service providers to provide services effectively but also for users to use services easily. In-this-paper,-we propose the architecture, functions and protocols of the NG mobile service platform of the NG mobile service platform which gives efficient means of connecting users and service providers to fulfill user-centric mobile services. Then we describe the NG mobile service environment with focusing on the NG service platform and how user-centric mobile services are provided in the NG mobile service environment. We then introduce the context aware follow-me (CAF) service developed as a prototype of promising NG user-centric mobile service followed by introduction of test- bed system developed to investigate feasibility of the CAF service.

Multi-flow transmission scheme in millimeter-wave mobile network with massive antenna structure

One of the key characteristics of next generation mobile networks is accommodating the data traffic which has rapidly increased. In order to increase overall capacity of mobile networks, using a vast amount of spectrum in millimeter-wave band is considered. By using a wide bandwidth, it is easy to enlarge capacity of mobile networks compare to that of 4G mobile networks. Furthermore, there are many researches to improve spectral efficiency such as beamforming technology and relay transmission. In this paper, we propose a multi-flow transmission scheme in massive antenna-based mobile network. With multi-flow transmission, UE can receive data from two beams independently. For the proposed scheme, we introduce a mobile network with a millimeter-wave band. To evaluate the performance of the proposed scheme, we have performed system-level simulation. From the results, we can find that system throughput is increased and packet delay is reduced by using multi-flow transmission.

An efficient handover scheme for providing the inter-beam mobility

This paper proposes an inter-beam handover (IBH) scheme in millimeter wave (mmWave) communication systems. Since the width of a beam transmitted by a base station (BS) is very narrow, the IBH can frequently occur within a BS. For this reason, the previous handover scheme based on the radio resource control (RRC) message can cause the increase of the signaling overhead. In addition, the performance of the IBH can be dramatically deteriorated because the strength of the received signal can be rapidly decreased at the edge of a beam. To solve these problems, the proposed scheme performs the IBH by exploiting the medium access control (MAC) control element (CE) to reduce the signaling overhead, and it applies the inter-beam coordinated scheduling (IBCS) to improve the strength of the received signal at the edge of a beam.

A study of the radio resource control connection re-establishment procedure on the UE side in 3GPP

The RRC(Radio Resource Control) protocol belongs to the 3GPP protocol stack and handles the control plane signalling of Layer 3 between the UE(User Equipment) and the eNB(Evolved Node B). The RRC Connection Re-establishment is one of the RRC main functions and re-establishes which involves the resumption of SRB1 (Signalling Radio Bearer) operation, the re-activation of security and the configuration. In this paper, we proposes the RRC Connection Re-establishment procedure on the UE side when the RLF(radio link failure) is detected or handover failure occurs, etc.