Research Areas
Below we list a few topics that the research lab is actively pursuing with the relevant references.
Real-Time Streaming Communications
Physical Layer Security
Mobile links are traditionally considered to be the weak links in secure communications. Our research overturns this assertion by developing new security mechanisms that exploit the unique characteristics of the wireless channels. For example the mobile channel undergoes rapid channel fluctuations and the channel gains vary significantly with the location of the receivers. Such properties are very useful for secure communications.
Sample Publications:
A. Agrawal, Z. Rezki, A. Khisti and M. S. Alouini Non-Coherent secret-key agreement with public discussion" IEEE. Trans. on Inf. Forensics and Security, Special Issue on Physical Layer Security, Sept 2011
A. Khisti, S. Diggavi and G. Wornell Secret-key agreement with Channel State Information at the Transmitter" IEEE Transactions on Forensics and Security, Special Issue on Physical Layer Security, 2011
A. Khisti and G. W. Wornell, "Secure Transmission with Multiple Antennas-II: The MIMOME Wiretap Channel, IEEE. Trans. Inf. Theory, Vol. 56, No. 11, pp. 5515-5532, Nov. 2010
A. Khisti and G. W. Wornell, "Secure Transmission with Multiple Antennas-I: The MISOME Wiretap Channel, IEEE Trans. Inf. Theory, Vol. 56, No. 7, pp. 3088-3104, July 2010
Real-Time Streaming Communications
The unprecedented growth of mobile devices in the last few years has exceeded even the most aggressive expectations. This has created a strong demand for streaming multimedia-rich content over mobile links. Traditional compression and communication techniques for video transmission are optimized under ideal channel conditions. Such solutions are far from efficient when the channels are not ideal. The proposed research investigates both fundamental limits and practical engineering solutions for delay-sensitive multimedia streaming over wireless networks.
In the figure above an encoder observes a sequence of source frames that need to be sequentially compressed into a sequence of packets as shown. When a particular packet(s) is erased a limited amount of error propagation is allowed at the destination. To our knowledge this is the first work to develop an information theoretic notion of error propagation.
A related research project also examines the construction of delay-sensitive error correction codes. These codes are specifically designed for streaming data and guarantee recovery of each packet by its deadlne in the presence of packet losses. The algebraic properties of these codes are very different than classical error correction codes.
Sample Publications:
F. Etezadi, A. Khisti and M. Trott" Prospicient Real-Time Codong of Markov Sources over Burst Erasure Channels: Lossless Case " To Appear DCC (2012)
A. Badr, A. Khisti and E. Martinian, " Diversity Embedded streaming erasure codes (DE-SCo): Constructions and Optimalty", IEEE JSAC, Special Issue on Trading Rate for Delay at Transport and Applciation Layers