11,574 research outputs found

    Performance Analysis of a Low-Interference N-Continuous OFDM Scheme

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    This paper investigates two issues of power spectrum density (PSD) and bit error rate (BER) of an N-continuous orthogonal frequency division multiplexing (NC-OFDM) aided low-interference time-domain scheme, when the smooth signal is designed by the linear combination of basis signals truncated by a window. Based on the relationship between the continuity and sidelobe decaying, the PSD performance is first analyzed and compared, in terms of the highest derivative order (HDO) N and the length of the smooth signal L. Since the high-order derivative of the truncation window has the finite continuity, the N-continuous signal has two finite continuities, which may have different continuous derivative orders. In this case, we develop a close PSD expression by introducing another smooth signal, which is also linearly combined by other basis signals, to explain the sidelobe decaying related to N and L. Then, in the context of BER, considering the multipath Rayleigh fading channel, based on the effect of the delayed tail of the smooth signal to the received signal, we provide a procedure for calculating the BER expressed in the form of an asymptotic summation.Comment: 7 pages, 6 figure

    Dark Energy and Normalization of the Cosmological Wave Function

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    Dark energy is investigated from the perspective of quantum cosmology. It is found that, together with an appropriate normal ordering factor qq, only when there is dark energy then can the cosmological wave function be normalized. This interesting observation may require further attention.Comment: Title changed, match the published versio
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