DFT-Based Wideband Line-of-Sight MIMO Communication

A solution is presented to the spatial-wideband effect in line-of-sight multiple-input multiple-output transmission. This effect, which arises once the bandwidth is large enough that the propagation delay differences for distinct transmit-receive antenna pairs become comparable to the symbol period, causes frequency selectivity and intersymbol interference. The proposed solution, which only entails channel-independent DFT precoding and reception, plus delay lines, performs close to capacity for most array orientations and is compatible with both multicarrier and single-carrier signals.

I. Introduction

Wireless systems continue their shift towards ever higher frequencies, where much idle bandwidth awaits. With 5G currently seizing mmWave bands, the attention of researchers is already moving to the subterahertz range (0.1-1 THz) [1]. Recent experiments with state-of-the-art solid-state electronics have demonstrated bit rates in excess of 100 Gb/s using 20 GHz of bandwidth at 300 GHz [2].