Handover in the Wild: The feasibility of vertical handover in commodity smartphones

Today commodity mobile devices are frequently equipped with two wireless access technologies, WiFi and 3G/4G. To enable continuous connectivity it is vital that these terminals provide for vertical handover between different technologies. Particularly, they should provide a vertical handover that complies with the timeliness requirements of soft real-time applications. Considering aspects such as cost- and ease-of-deployment, application neutrality, and, not least, the emergence of transport protocols that support multi-homing such as mobile SCTP and multi-path TCP, we think it would be beneficial to handle vertical handover in the transport layer of the mobile terminal. This paper demonstrates through several real-world experiments, the feasibility of using a lightweight vertical handover scheme in smart mobile terminals for live video streaming. The vertical handover criteria is based on the received signal strength. Our experiments suggest that the scheme indeed provides for seamless vertical handover at walking speed - our target scenario. However, the experiments also suggest that the scheme gives significant reductions in handover time, as compared to mobile SCTP without improvements, at higher speeds.