The invention relates to a fast timing
synchronizing method of a full-duplex communication
system, which belongs to the technical field of the timing synchronization of
wireless communication. The method is characterized by comprising the steps: adopting two identical PN code sequences as
pilot signals through a transmitting-terminal data frame, receiving the
signal through a receiving terminal, delaying the
signal for a PN code period, aligning a second PN code with a first PN code of the delayed received
signal, multiplying the first PN code and the second PN code by taking the first PN code and the second PN code as corresponding sampling points, counting the quantity of the multiplied values which are greater than a set threshold value in the length of the PN code period, carrying out the multiplication operation of the corresponding sampling points on the delayed receiving signal and the local PN code sequence if the statistic quantity is greater than a critical value of the quantity, then counting the quantity of the multiplied values which are greater than the set threshold value in the length of one PN code period, and if the statistic quantity still exceeds the critical value of the set quantity, determining the head part of a delaying unit as a timing
synchronizing point. By adopting the method, the timing synchronization is realized by ingeniously utilizing the self-correlation characteristic of the PN code and the random characteristic of the
noise, the multiplication times can be reduced, the
operand is reduced, the accumulation operation is not needed by adopting the threshold value comparison way, and the timing
synchronizing point can be rapidly and accurately found.