Cross-Domain Joint Channel and Data Estimation for mmWave MIMO-OFDM Systems With Low-Resolution ADCs

This paper proposes a novel cross-domain joint channel and data estimation (JCDE) algorithm based on expectation propagation (EP) for millimeter-wave (mmWave) multipleinput multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems equipped with low-resolution analog-todigital converters (ADCs). In the design of an EP-based messagepassing algorithm (MPA), messages are formulated by projecting the true posterior distribution of the unknown signal onto a Gaussian distribution through moment matching (MM), which can be modeled as the additive white Gaussian noise (AWGN) channel output of the unknown signal. Consequently, executing domain conversion within this message space enables signal processing in a suitable domain unaffected by quantization distortion. Specifically, the proposed algorithm consists of an antenna-delay (AD)-domain de-quantization (DQ) process that reconstructs the original signal prior to ADCs from quantized observations, a beam-delay (BD)-domain channel estimation (CE) that leverages the stochastic sparse structure of wireless channels, and an antenna-frequency (AF)-domain data detection (DD) that aligns with the OFDM format. This cross-domain strategy, tailored to the EP framework, facilitates low-overhead and high-precision JCDE. Computer simulations show that the proposed method not only significantly outperforms the state-of-the-art (SotA) but also approaches the performance of an idealized Genie-aided scheme under certain system conditions.