Jean-Paul M. G. Linnartz

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1 Abstract If C is a q-ary code of length n and a and b are two codewords, then c is called a descendant of a and b if c i 2 fa i ; b i g for i = 1; : : : ; n. We are interested in codes C with the property that, given any descendant c, one can always identify at least one of thèparent' codewords in C. We study bounds on F (n; q), the maximal cardinality of(More)
In biometrics, a human being needs to be identified based on some characteristic physiological parameters. Often this recognition is part of some security system. Secure storage of reference data (i.e., user templates) of individuals is a key concern. It is undesirable that a dishonest verifier can misuse parameters that he obtains before or during a(More)
Watermarks allow embedded signals to be extracted from audio and video content for a variety of purposes. One application is for copyright control, where it is envisaged that digital video recorders will not permit the recording of content that is watermarked as " never copy ". In such a scenario, it is important that the watermark survive both normal(More)
—In orthogonal frequency-division multiplexing, time variations of a multipath channel lead to a loss of orthogo-nality between the subcarriers, and thereby limit the achievable throughput. This paper proposes a general framework for a controlled removal of intercarrier interference (ICI) and channel acquisition. The core idea behind our method is to use a(More)
—Rapid time variations of the mobile communication channel have a dramatic effect on the performance of multicarrier modulation. This paper models the Doppler spread and computes its effect on the bit error rate (BER) for multicarrier code division multiple access (MC-CDMA) transmission and compares it to orthogonal frequency division multiplexing (OFDM).(More)
—In mobile reception, the reliability of orthogonal frequency division multiplexing (OFDM) is limited because of the time-varying nature of the channel. This causes intercarrier interference (ICI) and increases inaccuracies in channel tracking. In this paper, we model the ICI using derivatives of the channel amplitude. This allows us to design a relatively(More)
A novel mathematical method is presented to express the outage probability for a desired radio signal received from a mobile transmitter in the presence of multiple interfering signals with combined lognormal and Rayleigh fading. In contrast to previously reported analysis, this exact method avoids approximation of the pdf of the received powers of the(More)
tectable by dedicated software or hardware and very A watermark is a perceptually unobtrusiGe signal embedded in an image, an audio or video clip, or any other other multimedia asset. Its purpocie is to be a label which is holographically attached to the content. Moreover, it can only be removed by malicious and deliberate attacks (without a great loss of(More)
— We consider the problem of detecting a primary user signal over a wireless channel by a cognitive radio with multiple antennas. We present a multiple antenna processing based energy detector. In this detection method, the multiple copies of the primary user signal at the antennas of the cognitive radio receiver are combined and input to an energy(More)
—An array of a large number of LEDs will be widely used in future indoor illumination systems. In this paper, we investigate the problem of rendering uniform illumination by a regular LED array on the ceiling of a room. We first present two general results on the scaling property of the basic illumination pattern, i.e., the light pattern of a single LED,(More)