Patent ID: 7349500
Filing Date: 2008-03-25
Classification: H04L

Abstract:
1. A coarse frequency synchronization apparatus of an orthogonal frequency division multiplexing (OFDM) receiver, the apparatus comprising: a buffer that receives a demodulated signal X(k) and outputs a shifted signal X(k+d) generated by cyclically shifting the signal X(k) by a predetermined shift amount d; a controller that determines a length of a summation interval according to a phase coherence bandwidth and a number K of sub-bands into which the summation interval is divided, and generates and adjusts a symbol time offset according to the number K of sub-bands; a weighted phase reference signal (PRS) generating unit that generates a weighted phase reference signal Z(k) whose phase is shifted by the symbol time offset and that is weighted by a weighting vector determined according to a frequency sub-band; a counter that counts the shift amount d; a partial correlation unit that receives the shifted signal X(k+d) and the weighted phase reference signal Z(k), calculates a partial correlation value for each of the K sub-bands; and an offset estimator that calculates the shift amount d