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Chip-asynchronous version of Welch bound: Gaussian pulse improves BER performance. (English) Zbl 1152.94369

Gong, Guang (ed.) et al., Sequences and their applications – SETA 2006. 4th international conference, Beijing, China, September 24–28, 2006. Proceedings. Berlin: Springer (ISBN 978-3-540-44523-4/pbk). Lecture Notes in Computer Science 4086, 351-363 (2006).
Summary: We give a quadratic form expression of the mean squared multiple-access interference (MAI) averaged over relative time delays for chip-asynchronous DS/CDMA systems. A lower bound on the mean squared MAI is referred to as chip-asynchronous version of Welch bound, which depends on chip pulse shapes. Real analysis tells us that a pair of rectangular and sinc functions is one of Fourier transform and its inverse Fourier transform and vice versa. On the other hand, Gaussian pulses have the self-duality property. Gaussian chip pulses sacrifice inter-symbol interference, however, they give smaller mean squared MAI, as well as lower bit error rate, than the conventional Nyquist pulses.
For the entire collection see [Zbl 1147.94003].

MSC:

94A29 Source coding
42C10 Fourier series in special orthogonal functions (Legendre polynomials, Walsh functions, etc.)
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