Method for coarse frequency synchronization in OFDM receiver
The present invention provides a method for coarse frequency synchronization in an OFDM receiver. Even if the maximum variation of crystal oscillator (X-TAL) frequency disturbance is maximized and most of the variation in crystal oscillator (X-TAL) frequency disturbance is vary small, the estimation or search method of the present invention is capable of rapidly and effectively terminating the estimation of the integral multiple frequency offset (IFO). The integral multiple frequency offset (IFO) candidate is ascendingly increased and descendingly reduced at one value interval. In the estimation IFO, the correlation peak value in the intermediate status is compared to the thresholds, the coarse frequency synchronization (CFS) acquisition directly is ended and ensured when the correlation peak value is greater than the threshold, and a confidence check is not performed when correlation peak value is less than the threshold for considerably reducing the acquisition time of the CFS.
1. A method for coarse frequency synchronization in an orthogonal frequency division multiplexing (OFDM) receiver of an electronic apparatus, the method comprising the steps of:
configuring an initial value of an integral multiple frequency offset (IFO) candidate signal as a zero value and alternately increasing and reducing the integral multiple frequency offset (IFO) candidate signal at one value interval;
terminating an estimation signal of an unit IFO when a correlation peak value corresponding to the integral multiple frequency offset (IFO) candidate signal is greater than a first threshold;
neglecting a confidence check not to perform the confidence check since the estimation signal of an unit IFO is reliable when the correlation peak value is greater than a second threshold after terminating the estimation signal of the unit IFO, and ending an acquisition of a coarse frequency synchronization (CFS); and
defining the integral multiple frequency offset (IFO) candidate signal as a non-receiving status when the correlation peak value is less than a third threshold after terminating the estimation signals of the unit IFO, and ending an acquisition of a coarse frequency synchronization (CFS).
2. The method for coarse frequency synchronization in an OFDM receiver of claim 1 , wherein the first threshold is defined as a value which performs the confidence check and do not check a plurality of integral multiple frequency offset (IFO) candidate signals during the estimation signal of the unit IFO.
3. The method for coarse frequency synchronization in an OFDM receiver of claim 1 , wherein the second threshold is defined as a value which do not perform the confidence check and do not check a plurality of integral multiple frequency offset (IFO) candidate signals during the estimation signal of the unit IFO.
4. The method for coarse frequency synchronization in an OFDM receiver of claim 1 , wherein the third threshold is defined as a value which do not perform the confidence check to rapidly be determined as no channel available when the correlation peak value is less than the third threshold after checking a plurality of integral multiple frequency offset (IFO) candidate signals during the estimation signal of the unit IFO.