Iterative timing recovery via soft decision metrics of low-density parity-check decoding

An efficient scheme for iterative timing recovery via soft decision metrics (SDMs) of low-density parity-check (LDPC) decoding is presented. This scheme employs new metrics from LDPC decoding to overcome the difficult problem of timing synchronisation at low signal-to-noise ratios. It also obtains accurate timing acquisition with a search window-aided Nelder-Mead simplex algorithm by maximising the sum of the absolute values of the SDMs. The whole scheme is implemented, and our algorithm is concatenated with the Mueller-Mu-ller algorithm, which performs timing tracking with LDPC decoding feedback. Our scheme has global convergence, moderate complexity and good performance. The simulation results indicate that the performance of the LDPC-coded binary phase shift keying system with rather large timing errors is within 0.1-dB of the ideal code performance at the cost of some computation and storage resources.