Faster-Than-Nyquist (FTN) signaling is a promising technique for increasing the spectral efficiency of modern communication systems by transmitting symbols beyond the conventional Nyquist limit. This PhD research develops novel turbo equalizers based on Expectation Propagation and Kalman smoothing to efficiently mitigate the resulting inter-symbol interference. The proposed receivers achieve improved equalization performance while reducing computational complexity through a nonlinear sequential architecture that avoids matrix inversions. The study also incorporates Peak-to-Average Power Ratio (PAPR) considerations to identify operating regimes offering an attractive trade-off between performance, complexity, and power efficiency for satellite and high-mobility communications. Finally, new GLRT-based coarse synchronization methods for FTN signals are introduced, providing insights into the fundamental limitations and practical deployment of FTN systems.
