Wireless communications has had a profound effect on various aspects of our society and our way of life; from how we do business, to how we educate; from how we handle emergency situations, to how we care for patients and elderly. The promise of being able to exchange any amount of information, anytime, anywhere is prompting more and more subscribers to rely solely on their wireless devices for communicating sensitive nformation. As a result, offering a wide range of wireless services to more subscribers while preserving the security of information is becoming essential. Wireless system design efforts so far has aimed solely on providing high capacity. This research nvestigates the fundamental design principles of high capacity ireless systems that ensure secure information delivery.
This research includes the development of a comprehensive framework for the design of the multiuser physical layer that aims at achieving high capacity and secure transmissions for all users. The research addresses the existence of intruders that aim to disrupt communication by creating intentional interference, i.e., jammers; intruders that intercept the communication and attempt to decode the information of the users, i.e., eavesdroppers; and intruders that listen in on the communication and then create intentional interference accordingly, i.e., correlated jammers. Assuming a variety of levels at which the intruders are capable to harm the multiuser system, and using these scenarios as additional design constraints in the physical layer design, this research seeks to establish the performance limits of a variety of multiuser systems in nonfading and fading channels in the presence of security threats; the ways in which the system entities, i.e., transmitters and receivers, can collectively cope with security threats at the physical layer; and the jointly optimum transmit strategies for the users that render the intruders ineffective. The investigators study a variety of multiuser channels including scalar, waveform and vector multiple access and broadcast scenarios, as well as relay and cooperative communication scenarios and identify the fundamental design trade-offs for capacity versus security for a variety of wireless networks.
