Method and apparatus of detecting ISI/ICSI in an OFDM system

A method of detecting inter-carrier-symbol interference (ICSI) of a symbol for adjusting a boundary of the symbol utilized by an OFDM system, wherein each symbol includes a plurality of signals respectively transmitting via a plurality of sub-carriers, the method comprising:

• computing a first correlation value representing the correlation between at least one of first signals of a first symbol and at least one of second signals of a second symbol previous to the first symbol, wherein the at least one first signal is transmitted via a first sub-carrier and the at least one second signal is transmitted via a second sub-carrier adjacent to the first sub-carrier;
• computing a second correlation value representing the correlation between the at least one first signal and at least one of third signals of a third symbol next to the first symbol, wherein the at least one first signal is transmitted via the first sub-carrier and the at least one third signal is transmitted via the second sub-carrier;
• comparing the first correlation value with the second correlation value;
• and
• adjusting the timing of the boundary according to the comparison result;
• wherein the step of computing the second correlation value comprises;
• computing a conjugated value of the at least one first signal;
• multiplying the conjugated at least one first signal by the corresponding one of the third signals for generating a product value;
• and
• generating the second correlation value according to the summation of the product value.

An apparatus of detecting inter-carrier-symbol interference (ICSI) of a symbol for adjusting a boundary of the symbol utilized by an OFDM system, wherein each symbol includes a plurality of signals respectively transmitting via a plurality of sub-carriers, the apparatus comprising:

• a first correlator for computing a first correlation value representing the correlation between at least one of first signals of a first symbol and at least one of second signals of a second symbol previous to the first symbol, wherein the at least one first signal is transmitted via a first sub-carrier and the at least one second signal transmitted via a second sub-carrier adjacent to the first sub-carriers;
• a second correlator for computing a second correlation value representing the correlation between the at least one first signal and at least one of third signals of a third symbol next to the first symbol, wherein the at least one first signal is transmitted via the first sub-carrier and the at least one third signal is transmitted via the second sub-carrier;
• a comparator for comparing the first correlation value with the second correlation value;
• and
• a timing controller for adjusting the timing of the boundary according to the comparison result;
• wherein the first correlator further comprises:
• a conjugating unit for computing a conjugated value of the at least one first signal;
• a multiplying unit for multiplying the conjugated at least one first signal by the at least one second signal for generating a product value;
• and
• a correlation value computer for generating the first correlation value according to the product value.

An apparatus of detecting inter-carrier-symbol interference (ICSI) of a symbol for adjusting a boundary of the symbol utilized by an OFDM system, wherein each symbol includes a plurality of signals respectively transmitting via a plurality of sub-carriers, the apparatus comprising:

• a first correlator for computing a first correlation value representing the correlation between at least one of first signals of a first symbol and at least one of second signals of a second symbol previous to the first symbol, wherein the at least one first signal is transmitted via a first sub-carrier and the at least one second signal transmitted via a second sub-carrier adjacent to the first sub-carriers;
• a second correlator for computing a second correlation value representing the correlation between the at least one first signal and at least one of third signals of a third symbol next to the first symbol, wherein the at least one first signal is transmitted via the first sub-carrier and the at least one third signal is transmitted via the second sub-carrier;
• a comparator for comparing the first correlation value with the second correlation value;
• and
• a timing controller for adjusting the timing of the boundary according to the comparison result;
• wherein the second correlator further comprises:
• a conjugating unit for computing a conjugated value of the at least one first signal;
• a multiplying unit for multiplying the conjugated at least one first signal by the at least one third signal for generating a product value;
• and
• a correlation value computer for generating the second correlation value according to the product value.