Trials and deployment plans in the 26 GHz, 28 GHz and 39 GHz bands are piling up, but some mobile players believe even higher frequency spectrum must be harnessed to maximize the capacity of future 5G networks, and their potential to enable new services and experiences.
Nokia is one of the founders of the new mmWave Coalition, which will lobby US agencies such as the FCC, international regulators and the International Telecommunications Union (ITU), to open up bands above 95 GHz. They will try to build the same momentum behind these very high frequencies that is now seen below 40 GHz, ahead of the ITU’s World Radio Conference 2019, which will decide on global spectrum allocations for 5G.
Other founders include testing firm Keysight Technologies and Virginia Diodes. “The mmWave Coalition member companies are united in the objective of removing regulatory barriers to technologies and using frequencies ranging from 95 GHz to 450 GHz,” wrote Nokia’s Paul Norkus in a blog post.
This is not just about 5G. Norkus added: “While 5G and possibly even 6G(!) might look at these as potential frequency bands to use, the Coalition is not limiting itself to supporting any particular use or technology. Instead, it is working to create a regulatory structure for these frequencies that would encompass all technologies and all possible uses, limited only by the constraints of physics, innovation and the imagination.”
Nokia, as well as other vendors like Samsung, have already engaged in R&D around very high bands, and the FInnish firm has announced plans to conduct tests in the 90-96 GHz spectrum. Japan’s NTT used an experimental system in 125 GHz system way back during the 2008 Beijing Olympics.
And one of ETSI’s Industry Specification Groups, called mWT, was set up to promote the use of spectrum from 50 GHz up to 300 GHz for present and future critical transmission use cases.
Ultrafast point-to-point terrestrial wireless links are one possible application, but as Norkus said, these do not have to use 3GPP technologies. The IEEE, home of the standards which underpin WiFi and Bluetooth, is also active in this area, via its 802.15 WPAN Terahertz Interest Group (IGTHz).
If Nokia can attract additional heavyweight members to the Coalition, it could have significant impact, given that the new chair of the FCC is already well-disposed to its aims. Ajit Pai said earlier this year, in a speech to Carnegie Mellon University: “I believe that, instead of having regulators decide which frequencies are useful, we should put spectrum out there as a testbed and leave it to the innovators to figure out how to use it. Applications for experimentation above the 95 GHz band could qualify for Section 7 treatment. And this determination, in turn, could accelerate the deployment of cutting-edge wireless services and other innovations.”
Slightly lower down the spectrum, T-Mobile USA is asking the FCC for permission to test a microwave radio with integrated antenna in the E-band (71-76 GHz and 81-86 GHz). It will use the FibeAir IP-20E equipment from Ceragon.
TMO already holds a nationwide licence for the 70/80/90 GHz bands and operates links that are registered through a third party database system, but it still needs a Special Temporary Authority (STA) from the FCC to evaluate this equipment because, while the radio is FCC-certified, the antenna is currently not.
The test will focus on 5G solutions for high bandwidth, short hop radio links between buildings in urban environments. The location will be between two sites in Bellevue, Washington, where TMO is headquartered. The antennas will be mounted on the roof of each building.
FibeAir IP-20E promises to deliver capacity and spectral efficiency of up to 2.5Gbps over a 500 MHz channel, in a form factor which can be installed on light poles or other street furniture.
Currently, the 70/80/90 GHz (71-76 GHz, 81-86 GHz and 92-95 GHz) spectrum is lightly licensed in the US. More recently, the 71-76 GHz and 81-86 GHz bands have been considered as a potential candidate for mobile services by the FCC’s Spectrum Frontiers roadmap.
Back in more conventional 5G mmWave bands, Japan’s NTT Docomo has achieved data rates of 4.52Gbps on the downlink, over a distance of 1.2 kilometers, using 28 GHz mmWave spectrum. This was notable because high frequency spectrum is mainly associated with very short distances.
In a trial in Tokyo with Huawei, it installed a base station on the Tokyo Skytree Tower’s viewing deck at a height of 340 meters above ground, while user equipment was placed on the roof of a shopping facility at nearby Asakusa Station.
The trial achieved more than 4.52Gbps on the downlink and 1.55Gbps on the uplink despite a 10dBm penetration loss caused by the window glass of the viewing deck, said Docomo. During the trial, visitors were shown a demonstration of video communication using a Microsoft HoloLens augmented reality device.
“The high speed and long distance support are important technical challenges for 5G mmWave conditions,” commented Gan Bin, VP of Huawei’s 5G product line. “This successful long distance live demo on 5G mmWave is a groundbreaking achievement in our joint effort with NTT Docomo to build a fundamental 5G commercial environment. This success makes us more confident in realizing the goal of commercializing 5G by 2020.”