Reliable OFDM Transmission with Ultra-Low Resolution ADC
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The use of low-resolution analog-to-digital converters (ADCs) can significantly reduce power consumption and hardware cost. However, severe nonlinear distortion due to low-resolution ADCs makes achieving reliable data transmission challenging. Particularly, for orthogonal frequency division multiplexing (OFDM) transmission, the orthogonality among subcarriers is destroyed, which invalidates the conventional linear receivers that highly relies on this orthogonality. In this study, we develop an efficient system architecture for OFDM transmission with ultra-low resolution ADC (e.g., 1-2 bits). A novel channel estimator is proposed to estimate the desired channel parameters without their priori distributions. In particular, we integrate the linear minimum mean squared error channel estimator into the generalized Turbo (GTurbo) framework and derive its corresponding extrinsic information to guarantee the convergence of the GTurbo-based algorithm. We also propose feasible schemes for automatic gain control, noise power estimation, and synchronization. Furthermore, we construct a proof-of-concept prototyping system and conduct over-the-air (OTA) experiments to examine the feasibility/reliability of the entire system. To the best of our knowledge, this is the first work that focused on system design and implementation of communications with low-resolution ADCs worldwide. Numerical simulation and OTA experiment results demonstrate that the proposed system supports reliable OFDM data transmission with ultra-low resolution ADCs.
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