Impact of Major RF Impairments on mm-wave Communications using OFDM Waveforms

TL;DR

This paper investigates how RF impairments like phase noise, non-linearity, and I/Q imbalance affect mm-wave OFDM communication links, revealing robustness to impairments but highlighting phase noise as a critical factor for high-order modulation.

Contribution

It provides comprehensive models for joint RF impairments in mm-wave OFDM systems and evaluates their impact on channel estimation and link performance through simulations.

Findings

System is generally robust to RF impairments.

Phase noise significantly affects high-order modulation.

ICI from phase noise can limit system performance.

Abstract

In this paper, we study the joint impact of three major RF im-pairments, namely, oscillator phase noise, power amplifier non-linearity and I/Q imbalance on the performance of a mm-wave communication link based on OFDM modulation. General im-pairment models are first derived for describing the joint effects in each TX, each RX as well as a mm-wave communication link. Based on the obtained signal models and initial air interface de-sign from the mmMAGIC project, we numerically evaluate the impact of RF impairments on channel estimation in terms of channel-to-noise ratio (CNR) and also channel fluctuation due to common phase error (CPE) caused by phase noise within the channel coherence time. Then the impact on the link performance in terms of maximum sum rate is evaluated using extensive com-puter simulations. The simulation results show that the used air interface design is generally robust to the presence of RF impair-ments. With regard to the use of high order modulation alphabet and implementation of low-power and low-cost RF transceivers in mm-wave communication, special attention needs to be paid on phase noise where the inter-carrier-interference (ICI) can become a major limiting factor.