Francis Chung-Ming Lau

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—The performance of the noncoherent differential chaos-shift-keying (DCSK) communication system over a mul-tipath fading channel with delay spread is evaluated. Analytical expressions of the bit error rates are derived under the assumption of an independent Rayleigh fading two-ray channel model. Analytical and simulated results are presented and compared.(More)
This paper studies the performance of selected chaos-based communication systems whose spectrum overlaps with that of conventional narrowband systems. Such a scenario may occur in normal practice when chaos-based systems are introduced while the conventional systems are still in operation. The particular chaos-based systems under study are the coherent(More)
—In this paper, exact analytical expressions for the bit error rates (BERs) in a multiple-access chaos-based digital communication system are derived. Comparisons are made with those obtained using traditional approximation methods which assume a Gaussian distribution for the conditional decision parameter. The obtained results are compared to the results(More)
—Both the peak power and the average power of emission are limited in UWB systems in order to keep the interference caused in an already existing narrowband radio system low enough. It is frequently overlooked that these power limits have to be checked not over the transmitted UWB signal but at the output of a bandpass filter specified in the FCC(More)
The use of low-density-parity-check (LDPC) codes in coding digital messages has aroused much research interest because of their excellent bit-error performance. The behavior of the iterative LDPC decoders of finite length, however, has not been fully evaluated under different signal-to-noise conditions. By considering the finite-length LDPC decoders as(More)
With the use of belief propagation (BP) decoding algorithm, low-density parity-check (LDPC) codes can achieve near-Shannon limit performance. In order to evaluate the error performance of LDPC codes, simulators running on CPUs are commonly used. However, the time taken to evaluate LDPC codes with very good error performance is excessive. In this paper,(More)
—In this paper, we propose a generalized correlation-delay-shift-keying (GCDSK) scheme for noncoherent chaos-based communications. In the proposed scheme, several delayed versions of a chaotic signal are first produced. Some of them will be modulated by the binary data to be transmitted. The delayed signals will then be added to the original chaotic signal(More)