A Qualitative Method for Dynamic Transport Selection in Heterogeneous Wireless Environments A Qualitative Method for Dynamic Transport Selection in Heterogeneous Wireless Environments

by Duffin, Heidi R

Computing devices are commonly equipped with multiple transport technologies such as IrDA, Bluetooth and WiFi. Transport switching technologies, such as Quality of Transport (QoT), take advantage of this heterogeneity to keep network sessions active as users move in and out of range of various transports or as the networking environment changes. During an active session, the goal is to keep the device connected over the best transport currently available. To accomplish that, this thesis introduces a two-phase decision making protocol. In phase one, intra-device prioritization, users indicate the relative importance of criteria such as speed, power, service charge, or signal range through a comprehensive user interface. QoT-enabled devices process this information with the prioritized soft constraint satisfaction (PSCS) scoring function to ascertain the transport that best meets the user’s needs. The second phase, inter-device negotiation, facilitates two QoT-enabled devices in agreeing to a unified selection of the best transport. This phase uses a modified version of the PSCS scoring function based on the preferences of both users. Additionally, devices may utilize multiple transports simultaneously to more accurately meet user demands. The PSCS scoring function considers pairs of transports and calculates the ratio that will yield the desired performance. Another set of functions, also presented in this thesis, is then used to accomplish the desired performance level despite the potential introduction of additional overhead.