One of the dominating characteristics of all AmI systems is the spontaneous communication among invisible microcomputers that are integrated in mobile objects, i.e., in objects that constantly change their location. Examples include personal clothing or vehicle components. This requires wireless communication technologies such as Bluetooth, which support the establishment of so-called ad-hoc networks. Ad-hoc networks are characterized by the fact that mobile computers are no longer connected by means of a stationary radio network, but rather communicate with each other directly. This results in a change of paradigms in network technology that requires completely new solution approaches for stable communication services in such networks. Central challenges can be found in the areas of navigation, dynamically changing network structures as well as robustness of applications.
Regarding navigation, computers must be enabled to connect to other computers in a constantly changing environment, to query the services offered by these computers, and to make sensible use of these services for completing the tasks at hand. With regard to the dynamics of network structures, it must be assumed that the number of computers in an ad-hoc network and their (random) connection with each other is subject to constant changes. This leads to the question of how messages in such networks are transported between computers that are not located in immediate vicinity to each other. This requires designing completely new routing procedures and transport protocols that can handle the dynamics of these networks. Progress in these areas will lead to stronger integration of currently existing communication technologies such as the Internet (DSL, WLAN), GSM, UMTS, and thus to a mobile Internet.
Finally, concerning the robustness of applications, Mobile Computers cannot rely on calling on a stable offer of services, due to the spontaneous and temporally limited connection to neighboring computers. The mode of operation of mobile computers must take this fact into account and address it through intelligent withdrawal strategies should these services suddenly fail. The reliability thus achieved is the basic prerequisite for implementing critical technologies such as eHealth and eGovernment, which require major trust with regard to reliability as well as security with regard to the services rendered.
Overall, the requirements on mobile communication in AmI systems will create a bundle of new, challenging issues for which applied research must find solutions.