Department of Electrical and Computer Engineering

November 11, 2009

Nov. 11: ECpE Department Seminar - "Channel-based Spoofing in Wireless Networks"

All students, faculty, and staff are invited to the following ECpE Department Seminar:

Seminar title: "Channel-based Spoofing in Wireless Networks"

Speaker name: Larry J. Greenstein, Rutgers University WINLAB

Date: November 11

Time: 11 a.m. to 12 p.m.

Location: 3041 ECpE Building Addition

Abstract: Security is a major issue in all communications systems. Wireless systems are particularly vulnerable to attack because all signals propagate in a commonly used ether. The focus of this talk is on ‘spoofing’ attacks, wherein one party uses another party’s MAC address to gain access to a wireless LAN access point (AP).

The processes for detecting and foiling spoofing attacks generally reside in the higher layers of the protocol stack. Our aim has been to augment these processes by adding a technique at the physical layer that exploits a special property of the wireless channel. The payoff can be quantified in terms of either improved security or reduced overhead for the same level of security.

The ‘special property’ is that, in a rich scattering multipath environment, a link’s time or frequency response decorrelates rapidly with the spatial separation of paths. Thus, for example, two terminal-to-AP links have differently shaped frequency responses if the terminals are spaced by the order of a wavelength or more. That is, the terminals have different ‘fingerprints in the ether’. The fingerprints can be measured without additional overhead (e.g., by using the already existing pilot tones of an OFDM signal).

The basic ‘fingerprints’ approach to spoofing detection will be described, analyzed, and applied to a variety of scenarios to demonstrate its performance. The two metrics used are the probabilities of falsely rejecting a valid terminal (α) and missing the detection of a spoofing terminal (β). The tradeoff between α and β can be demonstrated using either a generic stochastic model of the channel response or a ray-tracing software tool for specific geometries, and we present both approaches. The study includes the effects of terminal mobility, environmentally-caused time variations, additive noise and interference, and receiver phase drift.

Speaker biography: Larry J. Greenstein received the bachelor's, master's, and PhD degrees in electrical engineering from Illinois Institute of Technology, Chicago, Illinois, in 1958, 1961, and 1967, respectively. From 1958 to 1970, he was with IIT Research Institute, Chicago, working on radio frequency interference and anti-clutter airborne radar. He joined Bell Laboratories, in Holmdel, New Jersey, in 1970. Over a 32-year AT&T career, he conducted research in digital satellites, point-to-point digital radio, optical transmission techniques, and wireless communications. For 21 years during that period (1979-2000), he led a research department renowned for its contributions in these fields. He is now a research scientist at Rutgers-WINLAB, North Brunswick, New Jersey, working in the areas of ultra-wideband (UWB), sensor networks, MIMO-based systems, Broadband Power Line systems and radio channel modeling, among others. Greenstein is an IEEE Life Fellow, an AT&T Fellow, a recipient of the IEEE Communications Society’s Edwin Howard Armstrong Award, and co-recipient of four best paper awards. He is currently director ofjournals for the Communications Society and has been a guest editor, senior editor and editorial board member for numerous publications.