Feasibility of SDN-based Vertical Handover between Bluetooth and Wi-Fi

In natural disasters, when essential network infrastructures are destroyed, Bluetooth networking can be a potential candidate to connect devices directly at a low cost and with little energy consumption. However, it typically permits short range communications, i.e., 10 meters. To communicate over a longer distance, the network needs more nodes or the nodes use another technology such as Wi-Fi. The Wi-Fi technology offers a wider communication coverage but it consumes more energy. Therefore, when two nodes change their connection from one wireless network to another due to the power limitation and the communication coverage, a vertical handover is necessary to maintain the ongoing session between them. In this paper, the performance of handover between Bluetooth and Wi-Fi is evaluated in a real testbed. The communication behavior of the system components is also described in order to explain why the delay in switching a TCP traffic from one accessing network to the other is less than 200ms. In case of UDP traffic, the results show that the jitter is mostly under 1ms, however, the packet loss rate varies from 1.6% to 5%. The results also show that the system saves the power consumption by activating both Wi-Fi and Bluetooth interfaces within a period of time as small as the handover delay.