Distribution Line Fitting-Based Channel Estimation Without Guard Symbols for OQAM/FBMC Systems

In this paper, we propose a distribution line fitting (DLF) based channel estimation method for offset quadrature amplitude modulation based filter-bank multicarrier (OQAM/FBMC) systems. Specifically, we firstly analyze the distribution characteristics of demodulated OQAM symbols at the receiver, and derive an intrinsic interference free relation between the real and imaginary parts of demodulated OQAM symbols. Then, based on the above derivation, we design a pilot structure of arbitrary columns of pilot symbols without guard symbols between pilot symbols and data symbols. Finally, the distribution lines can be fitted by utilizing the distribution characteristics of demodulated OQAM symbols and the channel frequency response can be estimated. Simulation results demonstrate that the proposed method with one column of pilot symbols outperforms the interference approximation method (IAM) in high signal-to-noise (SNR) regions and outperforms the pair of pilots (POP) method in all SNR regions in terms of bit error ratio (BER), and the proposed method with two columns of pilot symbols outperforms both IAM and POP in all SNR regions in terms of both BER and complexity.