|QoS MANET Ad-hoc networks Simulation wireless communication|
With the proliferation and miniaturization of electronic devices that today pervade almost all areas of our everyday life, wireless communication received a growing importance to interconnect them. Especially so-called ad hoc networks and collaboration allow for a variety of new applications. An important goal thereby is to enable wireless communication and access to different services without the need for a fixed infrastructure. This is especially important if such an infrastructure can only be deployed at high costs are has been destroyed in a disaster. For the successful use of a service it is first necessary to find matching service provers for a user. The publish/subscribe communication scheme provides an ideal solution for this problem as it abstracts from physical nodes and defines communication relationships based on the used data. In addition some services require a minimum quality of service to operate appropriately. In the contrary we have the inherent unreliable nature of the shared wireless medium and the dynamics of the network topology caused by the node mobility. In this thesis we will develop communication protocols to provide publish/subscribe communication with certain QoS guarantees in a mobile ad hoc network. We will start with a investigation of the properties of a IEEE 802.11 standard compliant multi-hop network in order to describe the problems and effects that can be experienced in practice as a model. The hereby gained knowledge will also be used to build a realistic simulation that provides the basis for the testing and evaluation of the developed protocols. The simulation will be complemented by real-world experiments to verify the results of different aspects of the system. In order to provide QoS guarantees we will combine a continuous monitoring of the link quality to our neighbor nodes, a cooperative estimation and coordination of the bandwidth utilization, and an online monitoring of the end-to-end properties. The developed communication protocols only rely on actual measured properties of the network. Upon these basic functions we will realize a publish/subscribe communication using multicast trees. We will use machine-readable content descriptions to minimize the processing overhead on intermediate nodes and hence the end-to-end delay. The developed protocols will be implemented as independent modules of a portable, event-based middleware. This middleware allows a dynamic composition and configuration of individual modules at run-time in order to consume only the resources required for a certain use case.