A vertical handover scheme from WMAN to WLAN by taking into account the maximum available resource

In heterogeneous wireless networks, the end users are expected to get more bandwidth from WLAN, other than from WMAN, for real time applications. However, adopting traditional Received Signal Strength (RSS) based approach could be inadequate for vertical handover. When WLAN is within the coverage of a WMAN Base Station, an associated Mobile Node (MN) can hardly connect to a WLAN Access Point (AP) due to the default high handover triggering threshold. On the other hand, without knowing the utilization information of scanned APs, once the MN handover to a busy AP by detecting a better signal, it may suffer from bandwidth contention. In this paper, we propose an efficient handover scheme, from WMAN to WLAN, to make use of the received signal to interference and noise ratio and the information about back-haul bandwidth for the criteria to trigger a handover. The time to start a handover is determined by considering the variations of data rate as the MN moves and the most suitable target AP is selected according to its maximum available bandwidth. The simulation results show that the MN consistently has a better throughput with the proposed scheme, as compared with the RSS-based vertical handover scheme. And among all candidates APs, the MN has the minimum packet delay with the selected AP association.