In this letter, a robust nondata-aided (NDA) carrier tracking method is proposed for low-density parity-check (LDPC) coded systems with symbol rate sampling. The proposed method has a novel and hybrid carrier tracking loop combined with the frequency-locked loop (FLL), increasing/decreasing sampling rate blocks, phase-locked loop (PLL), and modified symbol decision method, which is capable of improving estimation accuracy of the frequency offsets and phase offsets at low signal-to-noise ratios (SNRs). When applied to the   $(4096,3072)$   LDPC coded system, numerical simulations and comparisons are provided to validate the effectiveness of the proposed carrier tracking method in the case of relatively low SNRs.
['Yunhua Li', 'Bin Tian', 'Kechu Yi', 'Quan Yu', 'Dechun Sun', 'Zujun Liu']
A Robust NDA Carrier Tracking Method for LDPC-Coded Systems With Symbol Rate Sampling