Carnegie Mellon University Electrical and Computer Engineering Seminar

Mitigating Computer Platform Radio Frequency Interference in Embedded Wireless Receivers

Prof. Brian L. Evans
Dept. of Electrical and Computer Engineering
Wireless Networking and Communications Group
The University of Texas at Austin, Austin, Texas

Lead graduate students: Aditya Chopra, Kapil Gulati and Marcel Nassar

Research performed in collaboration with Keith R. Tinsley and Chaitanya Sreerama at Intel Labs

Thursday, October 9, 2008


Questions & Answers


Laptops and other computer platforms have many sources of radio frequency interference (RFI) that interfere with wireless reception. These sources include not only clocks and busses, but also power saving subsystems. We have developed methods for wireless receivers to sense and reduce platform RFI. These methods are complementary to the static circuit-level and board-level design methods used to mitigate the emission of platform RFI.

We model platform RFI as impulsive noise. In particular, we use Middleton Class A and Symmetric Alpha Stable impulsive noise models, which appear to fit platform RFI measurements obtained from Intel well. By passively listening to computing platform environment, we sense the platform RFI by estimating the parameters of the impulsive noise models. Given the model parameters, we employ a variety of filtering and detection methods to reduce the rate of bit errors by a factor of 10-100 for the same transmission rate. We evaluate design tradeoffs in the platform RFI sensing and reduction stages.


Brian L. Evans is Professor of Electrical and Computer Engineering at The University of Texas at Austin. He received his MSEE and PhDEE degrees in 1988 and 1993, respectively, from the Georgia Institute of Technology in Atlanta, Georgia, and his BSEECS degree from the Rose-Hulman Institute of Technology in Terre Haute, Indiana. He was a post-doctoral researcher at the University of California, Berkeley, before joining the faculty at UT Austin in 1996. His research efforts are in embedded real-time digital signal and image processing systems. His current projects include mitigation of radio frequency interference for wireless receivers; crosstalk cancellation, equalization, and adaptive bit swapping for multi-wire DSL systems; image processing algorithms for reflective displays; and distributed frameworks for streaming signal processing applications.

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