User-Centric Seamless Handover Scheme for Real-Time Applications in Heterogeneous Networks


IEICE TRANSACTIONS on Communications   Vol.E92-B   No.3   pp.867-877
Publication Date: 2009/03/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E92.B.867
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Network
seamless handover,  user-centric,  heterogeneous network,  real-time communication,  

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The authors propose a user-centric seamless handover (HO) scheme, which is a kind of a vertical HO from a new perspective, toward a next generation network where heterogeneous access networks converge. The users' experience-oriented scheme allows users to enjoy the optimal service quality for real-time applications in respective access networks. In addition, the scheme sustains on-going sessions during the vertical HO. The proposed scheme consists of two methods -- the bicasting of Different Quality-level Streams (DiffQS) and the Delay Difference Absorption (DDA) method. Initially, the authors propose two plausible methods for the SIP-based bicasting of DiffQS. This document introduces a SIP-capable network element named the HO Assistive Server (HOAS). HOAS controls bicasting of DiffQS and provides users with the optimal service quality for real-time applications via respective access networks as well as avoiding packet loss during HO. The DDA method is also proposed to prevent a service interruption and smoothly continue a real-time service during HO. Evaluation results show that the scheme achieves the seamless service continuity from the users' perspective for HO between cellular and high-speed wireless access via the implementation of a prototype system.