Code-aided carrier synchronization via soft decision feedback based on early stopping criterion

In order to solve the high complexity and high latency problem in current code-aided carrier synchronization scheme, a new code-aided carrier synchronization scheme which induces an early stopping mechanism is proposed. On the basis of the existing code-aided carrier synchronization structure, the proposed scheme makes decision of the loop signal to noise ratio (SNR) on the fly. The code-aided carrier synchronization will stop after the loop SNR exceeds a predetermined criterion with no performance degradation. With the improved phase estimation method, a carrier signal phase with phase noise can be estimated while the loop SNR also increases. Using 1/2 low density parity check (LDPC) code in simulation, the results show that the number of iteration in the proposed code-aided carrier synchronization decreases by about 50% when the bit error rate is 10^-5; with phase noise signals, the performance degradation is less than 0.15 dB as compared with the ideal decoding performance.