Abstract:

Regarding the carrier synchronization difficulty of low density parity check code minimum shift keying (LDPC-MSK) systems existed at low signal-to-noise ratios (SNR), a new code aided carrier synchronization algorithm is proposed. The soft decoding information is utilized to coarse synchronization based on cost function and fine synchronization based on maximum likelihood (ML) criterion. The reliable carrier synchronization is achieved by conducting the joint iteration of synchronizer, demodulator and decoder. Both the theoretical studies and the simulation results show that, at the low SNR, the efficient carrier synchronization can be achieved  with large frequency and phase offset. Almost ideal performance is obtained with rather low system complexity.