Blind synchronization with enhanced sum-product algorithm for low-density parity-check codes

We propose a blind synchronization scheme with soft phase error canceller using the sum-product algorithm for LDPC codes. Our scheme can perform frame synchronization, timing recovery, and carrier recovery without a phase lock loop (PLL). Furthermore, our scheme does not use a training signal and/or a preamble signal. The paper proposes the enhanced sum-product algorithm for the situations when the phase error is given by sample timing offset and carrier frequency offset. We show it is possible to perform the synchronization blindly, since the parameters of phase error can be estimated by the minimization of mean square error (MMSE) calculation with soft bits output of the sum-product algorithm.