Voice-activity-based vertical handover in 3G-WLAN interworking networks

A new vertical handover scheme for a VoIP connection is proposed, which makes use of the on-off characteristics of voice traffic by aligning the mutual silence period of the two parties engaged in conversation with the service disruption time as much as possible during the handover procedure. From the six-state Brady model, a simplified two-state Markov model is derived, by which the characteristics of both the talk-spurt period and the mutual silence period are obtained. The result shows that the proposed scheme significantly decreases the VoIP packet loss probability, while the resulting increased total time required for the vertical handover procedure is reasonable in the context of the 3G-WLAN handover scenario.