Se-Hyun Oh

A Performance Evaluation of Handoff Method between WLAN and cdma2000 1x Ev-Do System

In this paper, we suggest the data handoff method combine with Mobile IP and layer 2 triggering between WLAN and cdma2000 1x Ev-Do cellular network. The WLAN network has small cell coverage, but CDMA network covered with wide area. Then, the coverage of public WLAN network is overlapped with that of cellular network. In this network environment, mobile user should be requiring handoff service between WLAN and cellular network to use high quality and convenience service. We propose the inter system handoff method based on measuring the power of WLAN signal in multi-access network environments, and analyze the performance of handoff method in terms of delay and interruption time using test-bed system.

Cost-based approach to access selection and vertical handover decision in multi-access networks

In multi access network environments, mobile stations may encounter multiple choices for selecting an access network. Carefully designed access selection schemes can provide not only mobile users with better services but also network operators with better resource utilizations. It is also envisioned that further improvements can be achieved by redistributing mobile stations from one access network to anther (i.e., vertical handovers). Such decisions should be made by following carefully designed, yet simple to implement, protocols. In this paper, we present a cost-based scheme for access selection and vertical handover decision algorithms. The proposed algorithm was implemented in a Java-based simulator called MANSim (Multiple Access Network Simulator) that we developed. Our simulation results show that during the congested periods, the network throughput is significantly improved with greatly reduced call drop rate.