Research highlights Framework for Traffic Analysis in Wireless

Research highlights • Framework for Traffic Analysis in Wireless Networks, first exact solution for outage in cellular networks • 1 st paper on MC-CDMA • ICI mitigation in mobile OFDM • New Attacks on Watermarking • Detection theory applied to watermarking • Privacy in Biometrics 1

Research Highlight 1991: Framework for Traffic Analysis in Wireless Networks • Mathematical framework based on Laplace Transforms for the analysis of random access schemes (MAC ) for wireless networks (considering PHY) • Basic idea: – – Rayleigh fading gives exponential pdf of power Average performance = Laplace {performance | channel} Interference power = sum of power of individual components Average performance • Visibility, Impact, Results: – – Vederprijs 1992, MSc Cum laude, Ph. D cum laude Monograph published by Artech House (their 2 nd book on Wireless) More than 119 citations (+ 34 + 33 + 17 + 15 + 14 + 10 +. . ) Virtual Cellular Network: in Chinese cellular proposal 2

Research Highlight 1993: 1 st S/P paper on MC-CDMA Code N N Matrix B C N P/S I-FFT A • Basic idea: Frequency MC-CDMA Time OFDM Time DS-CDMA + + Time – cascade CDMA and OFDM, or equivalently, – define spreading codes in the frequency domain – Advantages in simultaneous user separation in multipath channels Frequency + - - + - + Frequency • Impact: – – Name and concept MC-CDMA proposed first in 1993 paper Citations 405 + 37 + 38 + 26 + 20 MC-CDMA has become a major research topic (85, 300 Google hits) MC-CDMA proposed in several standards (ETSI, IEEE 802) Credit also to Gerhard Fettweis 3

Research Highlight 2002 - 2004: ICI mitigation in mobile OFDM • Basic idea – series expansion of temporal behavior of subcarriers allows simple modeling of Inter Carrier Interference MMSE ICI canceller Conventional OFDM – Extension of statistical propagation model: behavior for derivatives • Impact, Visibility – – 2 IEEE Transactions papers (2004) patent applications Basis for solution implemented in two ICs: 15 + 10 + 8 citations 120 50 Credit also to Stan Baggen et al. 4

Research Highlight 1997: AWGN Image H-1 Watermark + H Detection theory applied to watermarking The basic idea • • • X MF H Watermarking is equivalent to the detection of weak signals in the presence of structure interference Hollywood content is not AWGN Exploit structure (predictability) in the content Impact • • • Papers, 60 + 19 + 15 +. . citations Basic patent granted on predictive filtering for WM detection Applied in Watercast product “you have seen content with our invisible watermarks, which are detected 24/24 on 1000 tv stations, using algorithms based on this idea” Credit also to Ton Kalker 5

Set of watermarked images Yes Research Highlight 1998: Space of images Yes New Attacks on Watermarking No No No • Basic Idea: – robustness of watermark requires contiguous No decision regions, whereas confidentiality of the key would require scattered chaotic regions – Search for point on “the” decision threshold of WM detector – Then evaluate sensitivity to small perturbations, say, dimension by dimension Yes No Set of random images • This strongly suggests the Conjecture: – Public-key watermarking can not exist • Impact – Patented countermeasures – IEEE Proceedings paper and IHW – Citations: 150 + 71 + 62 + 38 6

Research Highlight 2002: Privacy in Biometrics X The issue with conventional biometry: • Biometric template data can be misused by dishonest verifiers • • Someone who finds your passport can misuse your fingerprint How to set up a public data base for biometric verification? F(x) Y X F Y Basic idea: • One-way functions (cf. password protection) can be used if(f!) biometric measurements are preconditioned by ‘helper data’ • Information theoretic proof that helper data reveal less than e, that is, I(W; X) < e 0) Helper date does not need to affect reliability (FAR & FRR) • Impact • • fingerprint X G(x, w) F(x) Y noise N Helper data Challenge • W • • • leading theme for 10 fte project now at Philips Research, and project at universities. Potential impact: passports that contain verification data for biometrics, without allowing misuse Privacy protection even in public database with dishonest verifiers of fingerprint Basis for PUF Research Citations: 15 + 9 (since 2003) Tuyls, Willems: “effective cryptographic key length = Shannon capacity of biometric measurement channel” 7

Curriculum vitae: Education • • Masters: • Eindhoven University of Technology, The Netherlands • Ir. , Cum Laude, December 1986 PHD • Delft University of Technology, The Netherlands • Dr. , Cum Laude, December 18, 1991 • Promoter Prof. Jens Arnbak 8

Curriculum vitae: Professional experience • Physics and Electronics Lab (FEL-TNO): radio propagation models for frequency and operations planning – 1987 -1988: Research Scientist, on military service (ROAG) • Delft University of Technology: Teletraffic in wireless networks – 1988 -1991: Universitair Docent (Asst. Prof. ) – 1994: Universitair Hoofddocent (Assoc. Prof. ) • The University of California at Berkeley: Wireless Multimedia Communication – 1992 -1993: Assistant Professor – 1995 -1998: Adjunct Asst. Professor • Nat. Lab. Philips Research, Eindhoven: Conditional access, Copy management, Watermarks, Biometrics till 2003, Communication Systems after 2002 – 1995 -1998: (Senior) Research Scientist – 1998 -2000: Principal Scientist – 2001 -now: Department Head, Senior Director 9

Teaching experience • T. U. Delft – Transmission systems • U. C. Berkeley – Signal and Systems EECS 120, – Probability Theory EECS 226, started EECS 126, – Selected Topics in Communications EE 290 i: Wireless Communication • Short Courses & Tutorials – U. C. Extension: Wireless Communication Networks – Philips CTT: Wireless Basics; Advanced wireless; RF Transceivers; Co. Sec (Security and DRM) – EESI; PATO; IPA; EIDMA; WIC; EPFL • Coaching of students in during internships, and MSc, Ph. D, postdocs – UC Berkeley; TU Delft; Philips Research • Freelance radio presenter – • NOS, ROZ; various local radio stations; Internet webstation Educational CD-ROM and Internet – Kluwer; Springer 10