Pilot-Based TI-ADC Mismatch Error Calibration for IR-UWB Receivers

• Main Authors: Christian A. Schmidt, Jose L. Figueroa, Juan E. Cousseau, Andrea M. Tonello
• Format: Article
• Language: English
• Published: IEEE 2019-01-01
• Series: IEEE Access
• Subjects: Analog-digital conversion; error correction; receivers; ultra wideband technology
• Online Access: https://ieeexplore.ieee.org/document/8731991/
• ISSN: 2169-3536

In this work, we first provide an overview of the state of the art in mismatch error estimation and correction for time-interleaved analog to digital converters (TI-ADCs). Then, we present a novel pilot-based on-line adaptive timing mismatch error estimation approach for TI-ADCs in the context of an impulse radio ultra wideband (IR-UWB) receiver with correlation-based detection. We introduce the developed method and derive the expressions for both additive white Gaussian noise (AWGN) and Rayleigh multipath fading (RMPF) channels. We also derive a lower bound on the required ADC resolution to attain a certain estimation precision. Simulations show the effectiveness of the technique when combined with an adequate compensator. We analyze the estimation error behavior as a function of signal to noise ratio (SNR) and investigate the ADC performance before and after compensation. While all mismatches combined cause the effective number of bits (ENOB) to drop to 3 bits and to 6 bits when considering only timing mismatch, estimation and correction of these errors with the proposed technique can restore a close to ideal behavior. We also show the performance loss at the receiver in terms of bit error rate (BER) and how compensation is able to significantly improve performance.