A Background Calibration for Joint Mismatch in the OFDM System With Time-Interleaved ADC

Abstract

Time-interleaved analog-to-digital converters (TIADCs) are widely used in multi-Gigabit communication systems due to their high conversion rates. In practice, the offset, gain, and time-skew mismatch of TIADC significantly degrade the performance of an OFDM-TIADC system. It is also the case that the addition of channel coding can even degrade the system further. In this brief, we analyze the modulation error floor caused by mismatches and propose a two-stage background joint mismatch calibration using Least-square estimation to detect the offset and gain mismatches, and the time-skew mismatches are estimated by golden-section search. This method significantly reduces the bit error rate (BER) and improves the reliability of the OFDM-TIADC system.