Line-of-Sight MIMO for High Capacity Millimeter Wave Backhaul in FDD Systems

TL;DR

This paper presents a comprehensive design for high-capacity millimeter wave LoS MIMO backhaul systems using FDD, addressing physical impairments to achieve high spectral efficiency in dense wireless networks.

Contribution

It introduces a holistic solution with TO compensation, PHN estimation, and precoder optimization for LoS MIMO, improving robustness and spectral efficiency.

Findings

Achieves 60 bits/s/Hz spectral efficiency with 8x8 MIMO.

Proposes a joint solution for impairments in mmWave LoS MIMO.

Demonstrates robustness in high-density small cell backhaul scenarios.

Abstract

Wireless backhaul is considered to be the key part of the future wireless network with dense small cell traffic and high capacity demand. In this paper, we focus on the design of a high spectral efficiency line-of-sight (LoS) multiple-input multiple-output (MIMO) system for millimeter wave (mmWave) backhaul using dual-polarized frequency division duplex (FDD). High spectral efficiency is very challenging to achieve for the system due to various physical impairments such as phase noise (PHN), timing offset (TO) as well as the poor condition number of the LoS MIMO. In this paper, we propose a holistic solution containing TO compensation, PHN estimation, precoder/decorrelator optimization of the LoS MIMO for wireless backhaul, and the interleaving of each part. We show that the proposed solution has robust performance with end-to-end spectral efficiency of 60 bits/s/Hz for 8x8 MIMO.