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– As mobile computing increases in prevalence and popularity, it is becoming increasingly important to have a vertical handoff solution, which can perform a vertical handoff seamlessly and smartly. In this paper, we propose a Smart Decision Model to decide the " best " network interface and " best " time moment to handoff. A score function is utilized in(More)
Based on the IEEE 802.15.4 LR-WPAN specification , the ZigBee standard has been proposed to interconnect simple, low rate, and battery powered wireless devices. The deployment of ZigBee networks is expected to facilitate numerous applications, such as home healthcare, medical monitoring, consumer electronics, and environmental sensors. For many of the(More)
Knowledge of end-to-end path capacity is useful for video/audio stream adaptation, rate control and overlay design. Capacity estimation in wired and last-hop wireless networks has been extensively investigated, but an in-depth study of path capacity in ad hoc, multihop wireless networks is still lacking. Since the "capacity" of a wireless link can vary(More)
IEEE 802.15.4 is an emerging wireless standard addressing the needs of low-rate wireless personal area networks with a focus on enabling various pervasive and ubiquitous applications that require interactions with our surrounding environments. In view of the application potential of IEEE 802.15.4, knowing the fundamental network properties soon becomes(More)
— With the increasingly deployed Wireless Personal Area Network (WPAN) devices, channel conflict has become very frequent and severe when one WPAN technology coexists with other WPAN technologies in the same interfering range. In this paper, we study the coexistence issue between various IEEE 802.15 based WPAN technologies. We present analytical models on(More)
Knowledge of end-to-end path capacity is useful for video/audio stream adaptation, network management and overlay design. Capacity estimation in wired and last-hop wireless networks has been extensively investigated, but a thorough and systematic study in ad hoc, multihop wireless networks is still lacking. Yet the rate of a wireless link can change(More)
With wireless networking technologies extending into the fabrics of our working and operating environments, proper handling of intermittent wireless connectivity and network disruptions is of significance. As the sheer number of potential opportunistic application continues to surge (i.e. wireless sensor networks, underwater sensor networks, pocket switched(More)
The rapid deployment of wireless networks in various environments necessitates the development of new end-to-end tools that monitor and measure the properties of wireless paths well. In this paper, we implement AdHoc Probe, a recently proposed path capacity estimation tool specially designed for the multi-hop ad hoc wireless environment. We present an(More)
Opportunistic network is a type of delay tolerant networks (DTN) where network communication opportunities appear opportunistic. In this study, we investigate opportunistic network scenarios based on public network traces, and our contributions are the following: First, we identify the censorship issue in network traces that usually leads to strongly skewed(More)
We demonstrate a seamless vertical handoff solution, called Universal Seamless Handoff Architecture (USHA). USHA is simple and requires minimal modification to the current Internet infrastructure. Therefore, it is instantly ready for real-world deployment. In this demonstration, we present USHA in two scenarios. Using video streaming applications, we(More)