The capacity of low-density parity-check codes under message-passing decoding
IEEE Transactions on Information Theory
Iterative multiuser joint decoding: unified framework and asymptotic analysis
IEEE Transactions on Information Theory
Simulation-Based Computation of Information Rates for Channels With Memory
IEEE Transactions on Information Theory
Nonorthogonal pulseshapes for multicarrier communications in doubly dispersive channels
IEEE Journal on Selected Areas in Communications
Algorithms for iterative decoding in the presence of strong phase noise
IEEE Journal on Selected Areas in Communications
A novel graph-based soft interference cancellation algorithm for FDM-CPM satellite systems
ISIT'09 Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 4
A novel graph-based suboptimal multiuser detector for FDM-CPM transmissions
IEEE Transactions on Wireless Communications
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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.