FEC-Aided Decision Feedback Blind Mismatch Calibration of TIADCs in Wireless Time-Varying Channel Environments

Time-interleaved analog-to-digital converters (TIADCs) are widely used in communication systems due to their exceptionally high sampling rates; however, in real-world applications, the offset, gain, and time-skew mismatches in TIADCs are a significant challenge for the circuit system. This article proposes a forward error correction (FEC)-aided decision feedback blind mismatch calibration for TIADCs in the time-varying channels environment specific to the orthogonal frequency-division multiplexing (OFDM) system. In our proposed approach, we use an FEC decision feedback technique to generate a ground truth reference signal for the purpose of calibration. There are two stages. In the first stage, the offset and gain mismatches are estimated and corrected using standard techniques. In the second stage, an adaptive filter bank corrects the time-skew mismatch directly without the need for any additional calibration hardware. The coefficients of this adaptive filter are continuously adjusted in the background based on an error signal derived from the decision feedback ground truth signal. This calibration algorithm significantly reduces the bit error rate (BER) and improves the system performance. The efficacy of these approaches is validated through comprehensive simulations to attain a performance assessment, quantified by the BER, using a realistic wireless time-varying channel system configuration.