User-Centric Seamless Handover Scheme For Real-Time Applications In Heterogeneous Networks

The authors propose a user-centric seamless handover (HO) scheme, which is a kind of a vertical HO front 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 consist,, 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 set-vice 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.