Characterizing Quantization Errors in OFDM Parametric Channel Estimation for ISAC

The effects of quantization are often neglected in the context of parametric channel estimation (PCE) algorithms, which have garnered significant attention due to integrated sensing and communications (ISAC). The assumption of Gaussian quantization noise greatly simplifies the design of estimation algorithms, but it does not always hold. This paper provides conditions for the Gaussianity of the frequency domain quantization error in multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. To better understand the behavior of quantized OFDM systems, numerical explorations of the properties of the frequency domain quantization error as well as the impact of analog-to-digital converter (ADC) resolution on the OFDM space-alternating generalized expectation-maximization (SAGE) PCE algorithm are provided.