The FCC isn't the only agency starting work on spectrum for 5G technology. United Kingdom telecom regulator Ofcom released a consultation on Jan. 16 calling on industry to help lay the foundations for the UK's next generation of wireless communications.
Unlike the FCC's Notice of Inquiry on the subject, which focused on spectrum above 24 GHz, Ofcom is looking at spectrum starting at 6 GHz. Ofcom acknowledges finding spectrum in this range will be difficult, as it is currently used for everything from scientific research to satellite broadcasting and weather monitoring. Terrestrial fixed links, which also use the microwave bands, wasn't mentioned.
Steve Unger, Ofcom Acting Chief Executive, said, “We want the U.K. to be a leader in the next generation of wireless communications. Working with industry, we want to lay the foundations for the U.K.’s next generation of wireless communications. 5G must deliver a further step change in the capacity of wireless networks, over and above that currently being delivered by 4G. No network has infinite capacity, but we need to move closer to the ideal of there always being sufficient capacity to meet consumers’ needs.”
Ofcom Spectrum Group Director Philip Marnick said, “We want to explore how high frequency spectrum could potentially offer significant capacity for extremely fast 5G mobile data. This could pave the way for innovative new mobile services for UK consumers and businesses.”
Ofcom, as part of its Mobile Data Strategy, is already looking at bands below 6 GHz for future mobile systems and noted that 5G is likely to make use of existing mobile bands, aggregated with new bands.
The University of Surrey 5G Innovation Centre is one of the groups looking at developing 5G technology in the U.K. Among its founding member companies are the BBC, British Telecom, Fujitsu, Huawei, Samsung, Telefonica, Vodafone, and Rohde and Schwarz. The 5G Innovation Centre has stated a 5G vision of “always having sufficient rate to give the user the impression of infinite capacity.” Preliminary figures being discussed within the International Telecommunication Union (ITU) suggest peak data rates in the range of 10 to 50 Gbps and a latency of 1 millisecond.
The Ofcom consultation, Spectrum above 6 GHz for future mobile communications, seeks input from stakeholders on what spectrum bands above 6 GHz might be suitable for future mobile communications services. It notes that in addition to standardization of 5G technology, commercial deployment will depend on identification of suitable regional, and ideally globally, harmonized spectrum allocations.
The consultation notes that since the range of cell sites operating at higher frequencies could be 200 meters or less, lower frequency bands will continue to be needed for wide area coverage, requiring mobile devices that can operate over a wide range of frequency bands, both below and above 6 GHz. Ofcom asked stakeholders to comment on recent or emerging technologies that may provide effective solutions to the challenges of using higher frequency bands. Another question is whether there are any fundamental/inherent frequency constraints of the 5G technologies currently being investigated with regard to the minimum contiguous bandwidth per operation and the frequency range over which the technologies are expected to be able to operate due to propagation, availability of components, antenna designs and costs of deployment. As an example, Ofcom asks, “is 10-30 GHz better or worse than 30-50 GHz and why?” Ofcom is also looking for input on whether 5G technologies allow sharing high frequency spectrum with existing users.
The Ofcom consultation provides a detailed look at how the 6 to 100 GHz spectrum is currently being used in the U.K. and around the world to identify bands having potential use for 5G. These include 5925-8500 MHz, 10.5-11.7 GHz (excluding 10.68-10.7 GHz), 14.4-15.35 GHz, 17.8-19.7 GHz, 21.2-23.6 GHz, 25.25-29.5 GHz, 36-40.5 GHz, 42.5-52.6 GHz (excluding 50.2-50.4 GHz), and 55.78-76 GHz. Some of these bands overlap those discussed in the FCC's Notice of Inquiry.
Ofcom's time line shows commercial deployment of 5G technology beginning in the early 2020s. Considering the huge impact 5G could have on existing users of the identified spectrum--including broadcasters' fixed and portable links (as mentioned in the consultation)--it is difficult to see how any of the lower bands identified could be made available in under 10 years. This means initial roll-outs will likely be on spectrum above 15 GHz, where large amounts of contiguous spectrum have been identified and where highly directional antennas could make sharing the spectrum with existing users easier.