Experimental evaluation of line-of-sight multiple input multiple output (MIMO) transmission for sub-6 GHz carrier frequencies

Darko Cvetkovski; Thomas Schlegel; Eckhard Grass

doi:10.1515/freq-2020-0135

Article

Experimental evaluation of line-of-sight multiple input multiple output (MIMO) transmission for sub-6 GHz carrier frequencies

Darko Cvetkovski , Thomas Schlegel and Eckhard Grass

Published/Copyright: February 18, 2021

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From the journal Frequenz Volume 75 Issue 5-6

Abstract

For the next generation wireless networks, backhaul links with data rates of several Gbit/s are required. Line-of-Sight-MIMO with optimally arranged antennas can exploit the full multiplexing gain of orthogonal MIMO streams to achieve high throughput, as shown in recent works utilizing the 60 GHz mm wave band. In contrast, conventional MIMO systems operating at sub-6 GHz carrier frequencies, as utilized in modern WLAN networks, rely on rich scattering channels to enable reliable transmissions. In this work, we explore the feasibility of applying the LoS-MIMO concept to wireless single-carrier links operating at sub-6 GHz frequencies. For this, we investigate the sub-6 GHz LoS-MIMO channel in a 4 × 4 MIMO configuration by performing measurements in an anechoic chamber and an outdoor backhaul-like environment. In addition, different adaptive equalizers are evaluated. The results show, that the LoS-MIMO concept holds for sub-6 GHz frequencies both in pure LoS and in outdoor environments. It provides high multiplexing gain; however, the multipath propagation limits the potential performance of the equalizers in terms of achievable BER.

Keywords: adaptive equalization; backhaul; line-of-sight; MIMO; spatial multiplexing; sub-6 GHz

Corresponding author: Darko Cvetkovski, Department of Computer Science, Humboldt-Universität zu Berlin, Berlin and System Architectures Department, IHP – Leibniz-Institut für innovative Mikroelektronik, Frankfurt (Oder), Germany, E-mail: darko.cvetkovski@informatik.hu-berlin.de

Funding source: Deutsche Forschungsgemeinschaft

Award Identifier / Grant number: SPP-1655

Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: This work was supported in part by the German Research Foundation (DFG) in the framework of priority program SPP 1655 “Wireless Ultra High Data Rate Communication for Mobile Internet Access”.
Conflict of interest statement: The authors declare no conflicts of interest regarding this article.

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Received: 2020-08-21

Accepted: 2021-01-18

Published Online: 2021-02-18

Published in Print: 2021-05-26

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Articles in the same Issue

https://doi.org/10.1515/freq-2020-0135

Keywords for this article

adaptive equalization; backhaul; line-of-sight; MIMO; spatial multiplexing; sub-6 GHz