Sungkuen Lee

A wireless access network based on WDM-PON for HMIPv6 mobility support

In this paper, an IP-based wireless access network is proposed, which is designed to support the hierarchical MIPv6 standard on the wavelength division multiplexed passive optical network access network in order to provide a fast and seamless handoff support. Two schemes for enhancing the mobility management are included in the proposed network’s infrastructure support. Firstly, the local-link channels between sub-networks are provided to improve the mobility management efficiency for the mobile nodes roaming between neighboring sub-networks. Secondly, the early route optimization scheme has been applied, which optimizes the mobility management process between the corresponding node and the home agent (HA), resulting in reduced bandwidth waste and long end-to-end packet delays, as well as lowering the heavy burden on the HA. The performance of the proposed mobility management scheme has been evaluated in terms of handoff delays, packet losses and transmission costs. The superior performance of the proposed scheme has been verified and compared to other schemes.

Decentralized DBA scheme based on power detection in TDM-PON

In this article, we propose a new decentralized hardware-based DBA scheme in TDM-PON. Of particular significance in the proposed scheme is that the bandwidth of the uplink data transmission is dynamically allocated to each ONU without the intervention of the OLT. In this way, software-based DBA processing can be eliminated in the OLT and ONUs, resulting in the simple, fast, and cost-effective operation of the DBA in TDM-PON. The performance of the proposed scheme was evaluated by performing a statistical analysis and numerical analysis of the average packet end-to-end delay. We confirmed the superior performance of the proposed scheme by comparing the results obtained for this technique with those of other EPONs.

A design of WDM/TDM-PON provisioning for future optical access network upgrade

In this paper, we propose a PON-based access network based on conventional TDM-PON architecture for the smooth, economical and effective transition to the future optical access network. We also propose a dynamic MAC protocol for wavelength channel and bandwidth allocation in the TDM-PON subscriber networks, which can provide enhanced network scalability and flexibility, and greater adaptability to the increasing number of subscribers in TDM-PON. In the proposed dynamic MAC protocol, several key functions are manifested, such as multiple wavelength channel utilization and dynamic allocation of multiple time-slots to a user depending on SLA between OLT and ONUs to meet QoS requirements. A dedicated control channel is used for delivering the request and status information between OLT and ONUs. We evaluate the performances of the proposed MAC protocol thru a statistical queuing analysis and numerical simulations. In addition, through simulations using various traffic models we verify the superior performance of the proposed approach by comparing it with conventional TDM-PONs.

Network architecture and fast handover scheme using mobility anchor for UMTS-WLAN interworking

UMTS-WLAN interworking has attracted many research efforts because each of UMTS and WLAN can maximize its capability in service provisioning. Through UMTS-WLAN internetworking, users can be offered the most suitable services according to service area and service provider can reduce network building and maintenance costs. In this paper, we propose a network architecture and fast handover scheme using Mobility Anchor (MA) for UMTS-WLAN interworking. MA is provided at the boundary between GGSN and PDG, under the 3GPP-proposed interworking reference model. Such MA can enable authentication and session establishment before L2 handover of the mobile node, so that seamless and fast vertical handover could be possible. Through computer simulation using OPNET for the performance measurement, the efficiency and validity of the proposed scheme has been examined.

Design and Verification of Flow Mobility Scheme tn the AIMS System

The existing mobility management schemes do not fully support the next generation network, which is composed of IP-based core network and various access networks. Currently, ETRI has been developing the AIMS (Access Independent Mobility Service) system which satisfies the ITU-T requirements of mobility management in the next generation network. The AIMS system is designed to provide a mobile host with a fast and reliable mobility service among heterogeneous access networks. Recently, many user devices have multiple communication interfaces, e.g., 3G and WLAN, and thus they can make two or more network connections at the same time. In this paper, we design a scheme of flow mobility, i.e., the movement of selected data flows from one access technology to another, to be applied in the AIMS system, and verify the proposed scheme through the NS-3 simulation study. From the simulation results, we can know that the proposed flow mobility scheme can utilize the network resource efficiently in the heterogeneous mobile networks.

A Next-generation Mobility Management Scheme for an IPv4/IPv6 Dual-stack Terminal

In this paper, we propose a network-based IP mobility management scheme, called Access Independent Mobile Service with IPv4/IPv6 Dual Stack (AIMS-DS), which can provide high-quality multimedia services to IPv4/IPv6 dual-stack mobile nodes (MNs) without any interruption over various wireless/wired access networks. The proposed scheme provides an MN with a fast and reliable mobility service among heterogeneous wireless access networks through the network-based control, the complete separation method of control and data plane, the cross-layer (layer2 and layer3) interworking method for handover control acceleration, etc, In addition, the proposed AIMS-DS can provide seamless mobility service to an MN under the environments of IPv4/IPv6 coexisting networks through the home address mobility support and transport network support. Through performance evaluation with computer simulations, we have shown the superiority of the proposed AIMS-DS in terms of handover latency, packet 1085 and packet delivery latency.

Seamless Handoff Support for Real-Time Applications in the Next-generation Wireless Access Network Architecture

In this paper, we propose the seamless handoff support scheme for broadband real-time services, which is based on the wavelength division multiplexing-passive optical network (WDM-PON) technologies and HMIPv6 in the wireless access network. Firstly, the proposed scheme provides fast and seamless handoff support through the proposed reliable and efficient local-link channels between sub-networks in WDM-PON-based wireless access network. Secondly, the proposed WDM-PON-based access network architecture develops broadband wireless access network that accommodates the emerging bandwidth-intensive applications and multimedia services. We evaluated the performance of the proposed mobility management scheme in terms of handoff delay and packet loss by performing a computer simulation.

Micromobility Management Enhancement for Fast Handover in HMIPv6-Based Real-Time Applications

In this paper, we propose a fast handoff algorithm for micromobility management enhancement in HMIPv6 networks, which eliminates the DAD procedure involved in the regular HMIPv6 in order to decrease handoff latency and increase the resource utilization efficiency. In the proposed scheme, the MAP is designed to guarantee the uniqueness of MNs interface identifier within a MAP domain as long as the MN moves in a MAP domain, so that the MN configures the new address without the DAD procedure resulting in the decreased handoff latency significantly. When the MN resides in a subnet, MIPv6 is used adaptively as a mobility management protocol, which is to reduce bandwidth waste from the IP packet header overhead of IP-in-IP tunneling from the regular HMIPv6. Thru various computer simulation results, we verified the superior performance of the proposed scheme by comparing with the results of other schemes, MIPv6 and HMIPv6.

Power Detection-based TDM-PON for a Novel Decentralized DBA

In this paper, we propose the power detection (PD)-based TDM-PON architecture, which is implemented for a hardware-based decentralized DBA (dynamic bandwidth allocation) among ONUs, without OLTs intervention to service. The proposed approach is characterized by a simple, fast and cost-effective operation on TDM-PON.

Chirp Reduction by SPM and XPM Cancellation in DWDM Optical Transmission Systems

Chirp cancellation method is proposed to reduce XPM effects in DWDM optical channels, which is executed by controlling the time delay and power of transmitted pulses. Simulation results verify the effectiveness of the proposed method.