Disruptive Beamforming Trends – 4. QUB White Paper
In response to the challenges of designing 5G-ready beamformer hardware at mmWave (re. my article of the last three months), disruptive technological trends have emerged that are likely to change the way we look at mmWave beamforming hardware, like using a multi-stage lens-based beamformer, or a channel sounding technique based on a metallic cavity with sub-wavelength holes on one side and a scatterer placed inside, or to integrate the 3D beamformer radiation patterns measured in the field with the communication models.
A fourth technique is related to a very large mmWave array hardware. Beamformers at mmWave 5G can operate at full capacity when they have a very large number of radiating antennas. Each antenna is responsible to transmit a fraction of the total available radiated power, which means that each antenna must have a direct or indirect connection to the radio power source. This leads to cumbersome hardware at mmWave frequencies, where technology is not advanced enough to withstand high loss between the radio source and the antennas.
Using sparse antenna arrays is an alternative approach where the total radiated power from the access point is the same, while the number of radiating antennas is less than in a conventional antenna array, in which adjacent antenna spacing must be no larger than λ/2 to avoid grating lobes. Surprisingly, the direction of radiation (main lobe and side lobes) using a sparse antenna array can perfectly match that of a conventional antenna array using the Compressive Sensing [1-2] technique. The randomness of antenna locations in a sparse array avoids the introduction of grating lobes while allowing adjacent antenna spacing to be greater than λ/2. This means that a larger array size can be implemented using a relatively small number of antennas.
Conclusion:
The radio infrastructure required to support mmWave 5G is not ready yet, however, the disruptive technologies are pushing the limits of engineering to make it a reality by 2025. The fastest version of 5G is in fact the mmWave 5G and we are looking forward to the benefits of its ubiquitous ultra-high-speed and very low latency.
References:
1. M. A. B. Abbasi, V. Fusco and D. E. Zelenchuk, “Compressive Sensing Multiplicative Antenna Array,” in IEEE Transactions on Antennas and Propagation, vol. 66, no. 11, pp. 5918-5925, Nov. 2018.
2. Abbasi, M. A. B., & Fusco, V. “Hardware Constraints in Compressive Sensing Based Antenna Array,” In UK-China Emerging Technologies (UCET) Conference at the University of Glasgow, UK IEEE 2019.
Disruptive Beamforming Trends – 4. QUB White Paper
© Queens University Belfast 2020
About the Authors:
Dr. M. Ali Babar Abbasi is a researcher in the Centre for Wireless Innovation and lecturer at the School of Electronics Engineering at Queen’s University Belfast, UK. Profile.
Professor Vincent Fusco (FIEEE, FREng, FIAE, MRIA, FIET) is a researcher in the Centre for Wireless Innovation, Professor of High Frequency Electronics at the School of Electronics Engineering and CTO of the Institute of Electronics, Communications and Information Technology (ECIT) at Queen’s University Belfast. Profile.
For detailed information on our mmWave 5G beamformers, please contact Norbert Sagnard, Business Development Manager at Queen’s University Belfast [E] n.sagnard(at)qub.ac.uk
