9415530 Rappaport The problem of providing numerous mobile platforms with reliable switched communications over large areas is a major current world-wide technological challenge with significant hurdles. Network messages can be a mixture of voice, data, and stream traffic, and the mobile platforms may have various communications needs and mobility characteristics. With limited communication resources to service large populations essentially everywhere, the need to create suitable networking concepts along with analytical models and methodology that permit theoretical prediction of system performance, examination of parameter trade-offs, and cohesive views of relevant issues is acute. The physical complexity of potential systems and schemes sometimes makes analytical tractability elusive and limits the perspective and insight that is often gained from such models. The objective of the research is to devise new techniques and schemes that are suitable for mobile communications and to develop tractable models for performance analysis and comparisons. Computer simulation will be used as a validation and supporting tool. Of particular interest, from the viewpoint of networking, are techniques that provide intelligent features in the sense that they enable mobile networks to maintain performance levels by adjusting and adapting to changes in the communications environment. Dynamic control, assignment, and management of communications resources in consideration of traffic loading, interference, and topology will be investigated for cellular and non-cellular configurations. General areas to be investigated include: techniques for managing hand-offs of communicating platforms; use of spatial macro-diversity features; and dynamic control and assignment of communications assets - including both borrowing and sharing of channels and gateways. Procedures to accomplish this may involve mixtures of central and distributed control. Specific topics are: overall traffic pe rformance for cellular communication systems with hand-off; cellular systems with mixed call and platform types; hierarchically overlaid cellular architectures; combined channel and gateway borrowing; and autonomous channel assignment schemes. Appropriateness of the techniques in various access technologies will be considered. The research will emphasize the creation of analytically tractable models. This approach helps to establish a foundation that provides fundamental insights and fosters the invention of new and improved techniques of a particular genre. It is expected that as a result of this investigation, new techniques will be devised that will allow improved communications with large numbers of mobile platforms over wide geographical areas. In addition, the analytical models and approach will provide an enhanced foundation for understanding and designing mobile communications networks. *** ***************************************************************** ************ Aubrey M. Bush Program Director, Acting Deputy Divison Director Division of Networking and Communications Research and Infrastructure National Science Foundation 4201 Wilson Boulevard Arlington, VA 22230 703 306 1949 abush@nsf.gov
