Vertical handover: when the context matters

The increasing popularity of portable devices such as netbooks and smartphones, along with the wide deployment of wireless technologies such as Wi-Fi, WiMAX and UMTS, make users demand for continuous connectivity. This demand requires not only being attached to a network, but possibly to the best performing one, or at least to a network able to fulfill the user requirements. In order to choose the best network among different alternatives, the IEEE 802.21 standard has been developed. In this paper we propose a Vertical Handover (VHO) strategy which considers the maximum data rate per user as one of the decision criteria. We evaluate our proposal by means of packet delivery latency, channel throughput, usage dwell-time, and VHO event latency, under different network conditions. We demonstrate that the IEEE 802.21 standard must be used to perform vertical handovers when taking context into account to make an accurate decision. Moreover, we show that considering only the technology availability is not always the best criteria to choose the candidate network to perform the handover.