António R. Tavares

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There is a growing interest in wireless local area networks [1] that is a consequence of the large-scale utilization of personal computers and mobile communications. The portable personal computer integrates computational power and mobility in a single platform and introduces the need for accessing communication networks without the restrictions imposed by(More)
The performance of optical wireless transmission systems is mainly impaired by the shot noise induced by ambient light, interference produced by artificial light sources, transmitted optical power limitations due to high path losses and channel bandwidth limitations due to inter-symbol interference (ISI) produced by the multipath dispersion of the optical(More)
The main degrading factor of infrared communication systems is the shot noise due to ambient light. Due to the directional nature of both signal and noise, the signal-to-noise ratio (SNR) at the receiver can vary significantly. In order to minimise these SNR fluctuation effects, this paper discusses some advanced techniques for the design of non-directed(More)
A maximal-ratio angle-diversity receiver is composed of multiple sectors with relatively small field-of-views. Each sector estimates the signal-to-noise ratio (SNR) of the collected signal and its gain made proportional to the relation i / σ 2 , where i and σ represent the average signal and the shot noise root mean square (rms) values, respectively. The(More)
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