O. Kaya; "Achievable Rates, Optimum Signalling Schemes and Resource.."

Faculty of Engineering and Natural Sciences
FENS SEMINARS

Achievable Rates, Optimum Signalling Schemes and Resource Allocation for Fading CDMA Channels

Onur Kaya, University of Maryland

Abstract:
Increasing demand for higher rates in wireless communication systems has recently triggered major research to characterize the capacity of such systems. The wireless medium brings along its unique challenges such as fading and multiuser interference, which make the analysis of the communication systems more complicated. On the other hand, the same challenging properties of such systems are what give rise to the concepts such as diversity, which can be carefully exploited to the advantage of the network capacity.

In this talk, we focus on the uplink of a fading code division multiple access (CDMA) system, and we obtain its information theoretic capacity limits. Specifically, we characterize the optimal resource allocation and signalling strategies, that assign transmit power levels and/or signature sequences as functions of the available channel state information at the transmitters. The information theoretic framework not only helps us specify the optimum power and sequence allocation policies in the physical layer, but also dictates the optimum scheduling in the MAC layer, thereby yielding a cross layer design of wireless networks employing CDMA technology. Moreover, analytical solutions to the optimization problems lend themselves to practical iterative one-user-at-a-time algorithms, which have intuitive waterfilling interpretations.

Bio:
Onur Kaya received the B.S. degree in electrical and electronics engineering from Bilkent University, Ankara,Turkey, in 2000, and the M.S. degree in electrical engineering from University of Maryland, College Park, USA in 2002. He is currently a Ph.D candidate in the Department of Electrical and Computer Engineering, University of Maryland, College Park. His research interests are in the fields of communication theory and information theory, with particular focus on the optimization of wireless communication systems.

February 9, 2005, 15:00, 2019