Future mm-Wave Networks to Use Both Low & High Frequency Bands to Improve Performance

Thanks to ground-breaking research conducted by Huawei Technologies and IMDEA Networks Institute, a Madrid-based research body, future high-speed communication networks based on mm-Wave (30 to 300 GHz) will be more robust and efficient for delivering extremely high speed, high quality video, and multimedia content.

According to Dr. Joerg Widmer, the Principal Investigator on the project and Research Director at IMDEA Networks, a signal’s path loss increases significantly with its frequency. So, High Frequency (HF) communications, like mmWave systems which offer the speed and capacity that 5G and 802.11ad-standard Wi-Fi networks require, demand directional antennas in order to overcome the resulting attenuation. This results in high signaling overheads, since both ends of the communication link have to continuously update their antenna steering as nodes move and objects interrupt the line-of-sight path. These problems do not arise in low frequency (LF) networks, with their rich multi-path environment and much lower attenuation rates.

Under the project, the researchers have explored how to use low frequency bands to infer the channel characteristics of high frequency millimeter-wave bands and to support the network in terms of beam tracking, angle of arrival estimation, and location information. By studying this approach and other LF-HF channel correlations that may enable LF to assist HF, they have been able to develop techniques that improve performance in the millimeter-wave band and reduce the control overhead required to operate the network. The research team has demonstrated that the mechanisms and algorithms they developed work not only in theory but also in real-world wireless networking environments during the experimental evaluation phase of the project.

Widmer is particularly clear about the significance of the project. According to him, this was the first time that these two systems have been studied together, in depth. The team of experts achieved some really interesting results, developing techniques that will enable operators to improve their performance in the millimeter-wave band and thereby reduce the control overhead they require to operate their present and future networks.

The work has already resulted in two patent applications, with a third currently being evaluated for viability. According to Widmer, one of the most important challenges was to study the channel correlation that may enable LF to assist HF. The team had to consider a lot of variables in this study, such as the scenarios, power, and delay of the signal, number of paths, and the number of antennas of each system. The IMDEA Networks team was comprised of researchers with backgrounds in math, programming languages, material physics, radio frequency propagation and communication standards.

Published Paper: A Comprehensive Study of Low Frequency and High Frequency Channel Correlation by Pablo Jimenez Mateo, Alejandro Blanco, Norbert Ludant, Matteo Marugan Borelli, Amanda García-García, Adrian Loch, Zhenyu Shi, Yi Wang, Joerg Widmer