A Mm-Wave Wideband MIMO RX With Instinctual Array-Based Blocker/Signal Management for Ultralow-Latency Communication

Abstract

This article demonstrates a wideband mm-Wave multiple-input–multiple-output (MIMO) receiver (RX) system with cascadable array-based high-order autonomous spatial filters (ASFs) for closed-loop frontend beamforming, achieving “instinctual” (“Instinctual” is defined as an autonomous operation for sensing, controlling, processing signals with ultralow-latency and no backend digital signal processing assist.) management of multiblockers/signals with ultrafast response time. Over a full field-of-view (FoV), the ASFs achieve automatic blocker suppression and desired signal beamforming without prior knowledge on the angle-of-arrival/frequency/modulation and without beam-searching using backend computations. In particular, the ASFs realize frontend blocker suppression and substantially relax the dynamic range requirement of down-stream analog-to-digital converters (ADCs) in digital arrays. Moreover, cascading multiple ASFs can sequentially suppress multiple blockers, essentially achieving the “iterative source localization” DSP algorithm by the frontend hardware. A proof-of-concept 27–41-GHz four-element MIMO RX array is implemented in a 45-nm CMOS silicon-on-insulator (SOI) process to support multistandard 5G links in the future congested/contested electromagnetic (EM) environments. With autonomous cancellation of multiple co-channel wideband blockers, a wideband desired signal can be received with high signal-to-interference-plus-noise ratio (SINR), achieving −28.64-dB error vector magnitude (EVM) for 3-Gb/s 64QAM and −32.73-dB EVM for 0.8-Gb/s 256QAM. The measured MIMO beamforming response time for beam scanning, localization, and computation is $\mu \text{s}$ /stage, enabling 5G and beyond-5G ultralow-latency mm-Wave links.