A flexible QoS-aware service gateway for heterogeneous wireless networks

The integration of different types of wireless access networks, or heterogeneous wireless networks (HWN) is emerging. This article investigates in particular how a combination of UMTS (universal mobile telecommunications system) cellular networks, wireless LAN ad hoc networks, and DVB-H (digital video broadcasting handheld) broadcasting networks, called UWD networks for short, is constructed and managed to provide users with QoS-aware services. Given the complexity of the UWD networks, a novel policy-based service gateway is proposed. As a software framework sitting over and communicating with the UWD network, this UWD service gateway makes network management decision by reasoning over a set of predefined policies that describe the behaviors of the UWD network. Network variables such as bandwidth, delay, and mobility in policies are fuzzified using fuzzy control theory to make the service gateway (as well as the whole UWD network) more flexible and robust. Both the prototype implementation and the evaluation results indicate the feasibility and effectiveness of the system.