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Debunking the Myths About Millimeter Wavelengths for 5G

Debunking the Myths About Millimeter Wavelengths for 5G

by Reza Roufougaran, CTO, Movandi

One of the big reveals when the 5G standards were released was that it would expand the frequencies used by wireless carriers well into the millimeter-wave spectrum, orders of magnitude higher in frequency than the industry has ever used before. This spectral region has always been sparsely populated because of its challenging propagation characteristics, but for consumers, it offers more than its lower-frequency counterparts: immense bandwidth and low latency, the metrics that make video, AR, VR, and all other real-time applications possible.

However, the difficulty in harnessing this performance has led some to pronounce that operating in this region will be ruinously expensive for service providers, requiring immense numbers of small cell base stations to compensate for its inherent limitations. This debate continues, more than likely spurred not by these high frequencies, but by the fact that people expected everything within 5G to become available at once as if by magic.

That said, there is some merit to some of these negative pronouncements about millimeter-wave technology, at least if current network architectures are employed. But they don’t have to be, as better approaches are available and they’re being implemented now.

For example, Movandi has demonstrated that millimeter-wave technology can cost-effectively deliver exceptional performance using “smart” networked repeaters combined with cloud-based control and AI, beamforming, and other technologies. Not only does this approach simplify deployment, but it also improves the end-user experience, provides coverage virtually anywhere indoors, outdoors, or while mobile, and can reduce capital expenditures and the total cost of ownership by more than 40%.

Changing the Game

While 4G and its predecessors have traditionally expanded capacity and coverage primarily by adding more and more base stations, 5G millimeter-wave base stations have even more capacity but limited range. The result has been that the higher frequencies have not been fully utilized because when deployed in a legacy network, architecture and an enormous number of gNodeBs would be required.

The Movandi approach changes this paradigm, reducing the number of very expensive next-generation gNB radios while using more cost-effective smart repeaters to reach outdoors and indoors that are resistant to millimeter-wave signals. Movandi BeamXR powered repeaters, with their flexible form factors and low power consumption, can be placed virtually anywhere, from light poles to ceilings in office buildings and throughout stadiums and other large venues using simple mounting hardware. For this reason, Verizon Wireless has already adopted Movandi powered smart repeaters and is beginning deployment nationwide.

The Movandi architecture is based on the 5G millimeter-wave chipsets, RF power amplifiers, MIMO antennas, BeamXR smart repeater modules, and BeamX algorithms and software it has created. They provide mesh networking capability with redundant and dynamic routing and as well as control via cloud-based data centers with AI to balance and optimize network routing based on traffic and quality of connectivity. These innovations reduce the number of gNodeBs through load-balancing traffic across networks to provide continuous connectivity, even in moving vehicles.

The company’s BeamX software-defined beam networking (SDBN) mesh-networking capability expands coverage to difficult-to-reach locations while maintaining a high MIMO rank. The gNodeB signals are received by a Movandi repeater donor unit and then meshed with up to four additional server units via wireless or wired fiber or coaxial cable. The donor units can be placed at locations with high MIMO rank to maximize the signal-to-noise ratio and traffic capacity.

The solution also significantly reduces deployment complexity and ongoing maintenance and as they have optimized form factors that consume little power, they can help solve the onerous problems associated with permitting and legal fees. In short, the low cost (about $3,000) of Movandi powered repeaters lets wireless carriers expand and enhance millimeter-wave coverage to places where using traditional means would be far too expensive.

The concept has been proven in several studies conducted by Joe Madden, founder and chief analyst at Mobile Experts, who analyzed whether millimeter-wave repeaters can save money in a dense urban area and reduce deployment cost and complexity. For example, one study examined a neighborhood in Dallas covering 1.4 mi.2 with a high density of sub-6 GHz traffic.

During the peak hour, this area currently generates about 31 Gb/s of traffic, but by January 2024 it is expected to nearly double to 61 Gb/s. After comparing three deployment scenarios, he concluded that rather than employing large numbers of gNodeB radios, a mesh of repeaters can be an effective way to satisfy both coverage and capacity. It works equally well in mobile scenarios, as was demonstrated by Madden, and Movandi using Verizon’s millimeter-wave network. Data rates greater than 2 Gb/s were achieved while the vehicle was moving at various speeds, with no dropouts even during a Zoom call.

In short, what’s required is a new network design model in which smart repeaters, advanced software and algorithms, digital beamforming, and other techniques allow millimeter-wave signals to permeate RF-restrictive environments without dramatically increasing the number of small cell base stations. So, I beg to differ with those who believe millimeter-wave technology is “just around the corner and always will be,” because it’s already here and will get even more impressive in the future.