A design framework for all-digital mmWave massive MIMO with per-antenna nonlinearities

TL;DR

This paper presents an analytical model for the impact of nonlinearities in all-digital mmWave massive MIMO systems, providing hardware design guidelines to mitigate effects of low ADC precision and RF nonlinearities at high speeds.

Contribution

It introduces an analytical framework that quantifies nonlinearities' effects in mmWave MIMO, aiding in hardware design for high-speed, multiuser systems.

Findings

Performance bounds using intrinsic SNR concept.

Nonlinearities significantly affect system performance.

Guidelines for hardware design at 140 GHz, 10 Gbps per user.

Abstract

Millimeter wave MIMO combines the benefits of compact antenna arrays with a large number of elements and massive bandwidths, so that fully digital beamforming has the potential of supporting a large number of simultaneous users with {\it per user} data rates of multiple gigabits/sec (Gbps). In this paper, we develop an analytical model for the impact of nonlinearities in such a system, and illustrate its utility in providing hardware design guidelines regarding two key challenges: the low available precision of analog-to-digital conversion at high sampling rates, and nonlinearities in ultra-high speed radio frequency (RF) and baseband circuits. We consider linear minimum mean square error (LMMSE) reception for a multiuser MIMO uplink, and provide performance guarantees based on two key concepts: (a) summarization of the impact of per-antenna nonlinearities via a quantity that we term the "intrinsic SNR", (b) using linear MMSE performance in an ideal system without nonlinearities to bound that in our non-ideal system. For our numerical results, we employ nominal parameters corresponding to outdoor picocells operating at a carrier frequency of 140 GHz, with a data rate of 10 Gbps per user.