Enhanced Estimation of Channel and CFO in FBMC/OQAM via ZFBMC-Based Preamble

In next-generation communication systems, Filter Bank Multicarrier with Offset Quadrature Amplitude Modulation (FBMC/OQAM) has emerged as a promising alternative to Orthogonal Frequency Division Multiplexing (OFDM), offering enhanced robustness in multipath channels. However, like OFDM, FBMC/OQAM is susceptible to Carrier Frequency Offset (CFO), which can cause inter-carrier interference and performance degradation. This paper proposes a novel solution to the critical challenge of joint CFO and channel estimation in multipath fading environments. We propose a novel estimator that leverages a strategically designed training sequence within each frame's header. This sequence, comprising pilot symbols and Zero-FBMC symbols (ZFBMC), significantly improves the accuracy of joint estimation. To reduce computational complexity, we introduce an iterative algorithm based on Taylor approximation for CFO estimation. Extensive simulations demonstrate that our proposed estimators asymptotically approach the Cramer-Rao bound (CRB) for both joint CFO and channel estimation. Moreover, in scenarios with perfect CFO synchronization, our channel estimation method achieves near-optimal performance. These results underscore the effectiveness of our approach in enhancing FBMC/OQAM system performance, paving the way for its implementation in future communication networks.