A closed solution for an integrated broadband mobile system (IBMS)

Most current development strategies for future mobile systems are concerned with partial solutions only regarding the mobility-bit rate problem. In this paper the basic ideas of the integrated broadband mobile system (IBMS), supporting in a unified way a variety of communication classes ranging from high mobility with low data rates towards quasi-stationarity at high data rates, are presented. The key feature of this proposal is a closed system approach for both outdoor and indoor environment. Essential is the use of a single common, low bit-rate, generally available signalling channel for negotiation of the required service class or supporting the fallback to a lower service class if necessary. In the outdoor area, the use of smart antennas with strongly sectorized coverage will support high bit rates on behalf of reduced mobility speed, while simultaneously assuring efficient use of frequency spectrum. The same signalling channel will also be used to coordinate possible change of the mobile terminal to and forth between the outdoor provision and space limited indoor domains, operating on the picocell principle. Mobile terminals can be designed in a modular way to support all, or only some lower, bit rates. IBMS allows for an evolutionary extension starting from the infrastructure of today's digital cellular systems towards a multimedia and multiservice support of future universal personal communications using an ATM based communication backbone. IBMS is a joint research effort of Dresden University of Technology, Ilmenau University of Technology, Technical University of Berlin, and the Heinrich-Heaz-Institute Berlin sponsored by the German federal ministry of education, science, research and technology (BMBF) within the project line ATMmobil.