Chapter 19: Low-Resolution and Mixed-ADC Architectures

Learning Objectives

• Explain why ADC power dominates massive-MIMO receiver energy and formulate the ADC-power-vs-resolution budget
• Derive the 1-bit quantizer input-output map and the arcsine-law SNR characterization
• State the low-SNR capacity loss of the 1-bit receiver ($2/\pi$, or about 1.96 dB) and contrast with the infinite-precision baseline
• Apply the Bussgang decomposition to linearize a memoryless quantizer as $\mathbf{y}_q = \mathbf{B}\mathbf{y} + \mathbf{d}$ and compute the effective SINR
• Analyze mixed-ADC receivers that combine a few high-resolution chains with many 1-bit chains
• Pose optimal bit allocation across antennas as a constrained convex program and solve it with water-filling over antenna gains
• Compute bits-per-joule energy efficiency and identify the SNR regime where 1-bit beats 4-bit and vice versa
• Choose a constellation (PSK vs QAM) that is matched to 1-bit-ADC reception