This talk will consider two transmission control models for time-varying channels under transmission latency constraint.

The first model pertains to a single user, point-to-point transmission of a real-time traffic (such as two-way voice or video communication) with a constraint on average delay. This model includes a transmission buffer and finite state Markov model for time-varying radio channel and incoming traffic. In order to find the optimal transmission control, the problem is formulated as a Constrained Markov Decision Process. We will review the most important features of this model. It will be shown that the comparison between optimal transmission costs of two different time-varying channels can be performed by considering the stochastic dominance relation of their conditional probability distributions. As a consequence of this result, wireless channels with smaller scattering and identical means can achieve smaller average transmission cost for the same latency requirement. We will also discuss the extension of the basic model to cases with multiple channels, unknown channel state, and unknown traffic and/or channel statistics.

The second model considers the transmission over a time-varying channel of a very long file (a song from a music database) from a base station to a single user with a constant playback rate. The problem is to find the rate control that minimizes the transmission power subject to outage probability constraints in the receiver buffer and allows to maintain playback with a given degree of QoS.

Biography

Dejan V. Djonin received the B.Sc. and M.Sc. degrees from the University of Belgrade, Yugoslavia, in 1996 and 1999, and the Ph.D. degree from the University of Victoria, BC, Canada, in 2003. From 1998 to 2000, he was with the Department of Telecommunications, Institute Mihajlo Pupin, Belgrade where he worked on the development of an antenna array processing system. Since May 2005, he holds an NSERC Postdoctoral Fellowship at the Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC.

Dr. Djonin served as the Assistant Program Chair of the Wireless Communications and Networking Conference (WCNC) 2004 and as Technical Program Committee Member of ICC 2005 and Globecom 2003 Conferences. In 2002, he was awarded the "Outstanding Paper Award for Young Researchers" at the ISITA Conference. His research interests include wireless communications, information theory, stochastic control, and applications of control theory in multimedia communication systems.