QoS-Oriented Intersystem Handover Between IEEE 802.11b and Overlay Networks

In this paper, we consider the quality-of-service (QoS)-oriented intersystem handover between the IEEE 802.11b network and the overlay network. We propose the handover scheme and algorithm that guarantee to simultaneously meet the three key QoS parameters, that is, the minimum data rate, the maximum data block delay, and the maximum bit error rate, for the arbitrary number of downlink and uplink multiservice connections. In addition to the QoS requirements, our intersystem handover scheme guarantees to keep the call-dropping probability during the handover and the sum of the average number of ping-pong events during the entry to and the exit from the IEEE 802.11b system below the predetermined values. We define the IEEE 802.11b network as the priority network for the mobile station. Thus, we maximize the time during which the mobile station is served by the IEEE 802.11b network while satisfying the QoS requirements in both networks, as well as the maximum call-dropping probability and the maximum average number of ping-pong event constraints. To solve this task, we propose a novel intersystem handover scheme that utilizes the minimum signal-to-noise ratio threshold, entry hysteresis, and exit hysteresis.