We investigate the spectral efficiency, achievable by a low complexity symbol-by-symbol receiver, when linear modulations based on the superposition of uniformly time- and frequency-shifted replicas of a base pulse are employed. Although orthogonal signaling with Gaussian inputs achieves capacity on the additive white Gaussian noise channel, we show that, when finite-order constellations are employed, by giving up the orthogonality condition (thus accepting interference among adjacent signals) we can considerably improve the performance, even when a symbol-by-symbol receiver is used. We also optimize the spacing between adjacent signals to maximize the achievable spectral efficiency. Moreover, we propose a more involved transmission scheme, consisting of the superposition of two independent signals with suitable power allocation and a two-stage receiver, showing that it allows a further increase of the spectral efficiency. Finally, we show that a more involved equalization algorithm, based on soft interference cancellation, allows to achieve an excellent bit-error-rate performance, even when error-correcting codes designed for the Gaussian-noise-limited channel are employed, and thus does not require a complete redesign of the coding scheme.

Time-frequency packing for linear modulations: spectral efficiency and practical detection schemes / Barbieri, A; Fertonani, D; Colavolpe, Giulio. - In: IEEE TRANSACTIONS ON COMMUNICATIONS. - ISSN 0090-6778. - 57:(2009), pp. 2951-2959. [10.1109/TCOMM.2009.10.080200]

Time-frequency packing for linear modulations: spectral efficiency and practical detection schemes

COLAVOLPE, Giulio
2009-01-01

Abstract

We investigate the spectral efficiency, achievable by a low complexity symbol-by-symbol receiver, when linear modulations based on the superposition of uniformly time- and frequency-shifted replicas of a base pulse are employed. Although orthogonal signaling with Gaussian inputs achieves capacity on the additive white Gaussian noise channel, we show that, when finite-order constellations are employed, by giving up the orthogonality condition (thus accepting interference among adjacent signals) we can considerably improve the performance, even when a symbol-by-symbol receiver is used. We also optimize the spacing between adjacent signals to maximize the achievable spectral efficiency. Moreover, we propose a more involved transmission scheme, consisting of the superposition of two independent signals with suitable power allocation and a two-stage receiver, showing that it allows a further increase of the spectral efficiency. Finally, we show that a more involved equalization algorithm, based on soft interference cancellation, allows to achieve an excellent bit-error-rate performance, even when error-correcting codes designed for the Gaussian-noise-limited channel are employed, and thus does not require a complete redesign of the coding scheme.
2009
Time-frequency packing for linear modulations: spectral efficiency and practical detection schemes / Barbieri, A; Fertonani, D; Colavolpe, Giulio. - In: IEEE TRANSACTIONS ON COMMUNICATIONS. - ISSN 0090-6778. - 57:(2009), pp. 2951-2959. [10.1109/TCOMM.2009.10.080200]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2282321
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