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.File | Dimensione | Formato | |
---|---|---|---|
j46.pdf
non disponibili
Tipologia:
Documento in Post-print
Licenza:
NON PUBBLICO - Accesso privato/ristretto
Dimensione
291.2 kB
Formato
Adobe PDF
|
291.2 kB | Adobe PDF | Visualizza/Apri Richiedi una copia |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.