EECS CSPL SEMINAR SERIES
WINTER TERM 2000


Dennis Goeckel

Prof. Dennis L. Goeckel

Electrical and Computer Engineering

University of Massachusetts - Amherst

goeckel@ecs.umass.edu



Thursday, March 2
4:00 - 5:00 P.M.
Room 1001 EECS


Adaptive Communication under Measurement Uncertainty

Abstract-
Because of the wide range of environments encountered by a wireless communication system as conditions evolve over time, it is well-established that performance gains can be obtained if the system is able to adapt to the current transmission environment. However, by definition, this adaptation must rely on measurements of the current environment; such measurements are inherently outdated and/or noisy, particularly in a system supporting high user mobility. In this talk, we will concentrate on adaptive system design in environments where there is a well-accepted class of statistical models that characterize how the current environment depends on available measurements. In particular, the problems of: (1) adaptive coding based on multipath fading estimates, and (2) adaptive power control based on estimates of the log-normal shadowing, will be considered in detail. The focus will be on how the uncertainty in the measurements alters the basic design philosophies of the adaptive system in each of these cases. Numerical results will be presented that demonstrate both the impact of considering measurement uncertainty in system adaptation and the general benefits/detriments of system adaptation. Issues of robustness to model uncertainty will also be addressed.





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