Joint time-domain correlation and code-aided carrier synchronization algorithm

Considering low estimation accuracy and small synchronization range of carrier synchronization algorithms in low signal-to-noise ratio (SNR) for short burst communication systems, a joint time-domain correlation and code-aided carrier synchronization algorithm is proposed. Firstly, a frame structure in which the pilot symbols are separated with data symbols is used. Then, a new frequency estimation method using the summation of the entire cross correlation is deduced based on the time-domain correlation frequency estimation criterion. Based on this, the summation of the cross correlation of the pilot symbols after removing modulation is utilized to perform coarse synchronization and of the pilot symbols and decoding soft information is utilized to perform fine synchronization. So a joint time-domain correlation and code-aided carrier synchronization algorithm is obtained. Simulations by the Turbo code verify that the proposed algorithm can obtain higher estimation accuracy with only 32 QPSK pilot symbols, and the SNR degradation of Turbo decoder is within 0.5dB when the normalized frequency offset is smaller than 1.5×10^-3.