Time domain symbol timing synchronization circuit and method thereof for communication systems

A receiver in a communication system, the receiver comprising:

• an converter, for converting analog input signals into digital signals;
• a receiver frontend, coupled to the converter, for performing signal processing on the digital signals from the converter;
• a FFT unit, coupled to the receiver frontend, for performing FFT on output signals from the receiver frontend;
• a receiver backend, coupled to the FFT unit, for performing signal processing on output signals from the FFT unit;
• and
• a time domain symbol timing synchronization circuit, coupled to the receiver frontend and the FFT unit, for indicating symbol boundary of received communication symbols and getting symbol boundary of the received communication symbols with phase reference sequences performing like pseudo-noise sequences,
• wherein:
• the time domain symbol timing synchronization circuit compares a position at a peak of a current cyclic prefix autocorrelation function of the received communication symbols and a position at a peak of a previous cyclic prefix autocorrelation function of the received communication symbols;
• if (a) a difference of the positions is larger than a threshold and (b) the peak of the current cyclic prefix autocorrelation function is smaller than a reference average peak, the peak of the current cyclic prefix autocorrelation function is determined as false;
• the time domain symbol timing synchronization circuit weeds out and replaces the position at the peak of the current cyclic prefix autocorrelation function by the position at the peak of the previous cyclic prefix autocorrelation function;
• and the current peak is not introduced in calculation of the reference average peak.

A time domain symbol timing synchronization method for communication systems, the method comprising:

• (a) searching a position at a peak of a previous cyclic prefix autocorrelation function of the received communication symbols;
• (b) searching a position at a peak of a current cyclic prefix autocorrelation function of the received communication symbols;
• (c) comparing the peak positions;
• (d) if a difference between the peak positions is larger than a threshold and the peak of the current cyclic prefix autocorrelation function is smaller than a reference average peak, weeding out and replacing the position at the peak of the current cyclic prefix autocorrelation function by the position at the peak of the previous cyclic prefix autocorrelation function;
• and
• (e) indicating symbol boundary of the received communication symbols based on the peak position which is not wed out.