JSSC 2020第5期RF & Wireless65nmPhased ArrayNeural Network Accelerator

Code-Domain Multiplexing for Shared IF/LO Interfaces in Millimeter-Wave MIMO Arrays Manoj Johnson , Student Member , IEEE, Armagan Dascurcu, Student Member , IEEE, Kai Zhan, Student Member , IEEE, Arman Galioglu, Student Member , IEEE, Naresh Kumar Adepu, Student Member , IEEE, Sanket Jain, Student Member , IEEE

提出了一种码域复用技术，用于毫米波MIMO系统中的共享IF-LO接口。

28 GHz, 65-nm CMOS, 1.2 V, 60 mA, 5.75 mm²

毫米波MIMO码域复用IF-LO接口数字波束成形

▸创新点1：码域复用技术（方法创新） - 提出了一种基于码域的信号复用方法，通过编码技术将不同天线单元的信号以及本振信号复用到单一接口上，有效解决了大规模MIMO阵列的I/O瓶颈问题，实现了高密度信号传输。

▸创新点2：共享IF-LO接口（系统创新） - 设计了一种共享中频（IF）和本振（LO）的接口架构，显著减少了硬件复杂度和功耗，每个阵列单元仅消耗60mA电流（1.2V供电），同时实现了16dB的转换增益。

▸创新点3：无移相器/合路器设计（电路创新） - 通过数字化波束成形技术替代传统模拟移相器和合路器，使芯片面积缩小至5.75mm²（65nm CMOS工艺），并实现了λ/2×λ/2的天线间距兼容性，适用于紧凑型毫米波MIMO系统。

▸创新点4：28GHz四单元MIMO接收机实现（系统验证） - 在65nm CMOS工艺上成功实现了工作于28GHz的四单元MIMO接收机原型，通过实测验证了基带信号解复用和数字波束成形的可行性，为毫米波大规模阵列提供了可扩展的解决方案。

Abstract

Millimeter-wave (mm-wave) multi-input–multi- output (MIMO) systems with the digitization of every element enable spatial multiplexing, virtual arrays for radar, and digital beamforming for high mobility scenarios. However , per-element digitization results in a formidable I/O challenge in large-scale tiled MIMO mm-wave arrays. This article analyzes a code- domain approach to multiplex signals from different elements as well as the LO on a single interface. System considerations are presented, and the approach is demonstrated through a 28 GHz four-element MIMO receiver in 65-nm CMOS. Measurements show the feasibility of digital beamforming after de-multiplexing of the baseband signals from the IF/LO interface. Each element in the array achieves 16-dB conversion gain while consuming 60 mA from 1.2 V . The IC occupies 5.75 mm 2 in 65-nm CMOS, achieving small size and compatibility with λ/2 × λ/2 antenna spacing due to the absence of phase shifters/combiners required in phased arrays.