ORTHOGONAL FREQUENCY DIVISION MULTIPLEXER

摘要

PROBLEM TO BE SOLVED: To provide an orthogonal frequency division multiplexer that improves retransmission efficiency and the reliability of a demodulation signal. SOLUTION: An FFT circuit 101 applies FFT processing to a received signal and outputs a signal assigned to each subcarrier. Level detectors 119-122 detect the level of the signal assigned to each subcarrier. An averaging processing circuit 115 generates a channel quality inferred value. A discrimination device 117 compares the channel quality inferred value with a threshold. A switch 118 outputs threshold 1 or 2 to digital subtractors 123-126, on the basis of the comparison result from the discrimination device 117. The digital subtractors 123-126 subtract signals from the level detectors 119-122 from the threshold of the switch 118. Discrimination devices 127-130 discriminate a subcarrier which is the object of retransmission, on the basis of the result of subtraction.