Droop Compensation Technique with Simple Structure for OFDM mobile transmitter

Generally the system clock is same to OFDM time sample rate at OFDM mobile systems to reduce the power consumption of handheld systems. For this reason, the droop phenomena that both edges of frequency channel band fall down is occurred by the sample-and-hold operation of digital to analog converters. In this paper, we have proposed the compensation technique to predistort the OFDM subcarriers with the inverse sine before the inverse fast Fourier transformation operation. The proposed technique can be implemented with the one multiplier and look-up table to save inverse sine weighting values operating to the low frequency. We have presented the simulation results on the droop compensation with WiBro standard based on OFDMA in Korea and the measurement results on the droop compensated frequency response