Massive MIMO Channel Estimation With Low-Resolution Spatial Sigma-Delta ADCs

• Main Authors: Shilpa Rao, Gonzalo Seco-Granados, Hessam Pirzadeh, Josef A. Nossek, A. Lee Swindlehurst
• Format: Article
• Language: English
• Published: IEEE 2021-01-01
• Series: IEEE Access
• Subjects: Channel estimation; low resolution ADCs; massive MIMO; ΣΔ ADCs; one-bit ADCs
• Online Access: https://ieeexplore.ieee.org/document/9500125/

We consider channel estimation for an uplink massive multiple-input multiple-output (MIMO) system where the base station (BS) uses an array with low-resolution (1-2 bit) analog-to-digital converters and a spatial Sigma-Delta (<inline-formula> <tex-math notation="LaTeX">$\Sigma \Delta $ </tex-math></inline-formula>) architecture to shape the quantization noise away from users in some angular sector. We develop a linear minimum mean squared error (LMMSE) channel estimator based on the Bussgang decomposition that reformulates the nonlinear quantizer model using an equivalent linear model plus quantization noise. We also analyze the uplink achievable rate with maximal ratio combining (MRC), zero-forcing (ZF) and LMMSE receivers and provide a lower bound for the achievable rate with the MRC receiver. Numerical results show superior channel estimation and sum spectral efficiency performance using the <inline-formula> <tex-math notation="LaTeX">$\Sigma \Delta $ </tex-math></inline-formula> architecture compared to conventional 1- or 2-bit quantized massive MIMO systems.