It is common wisdom these days to say that there is a “spectrum crunch.” That is, that we, the consuming public, are consuming more and more wireless data, and that the companies that provide us access to this data (the mobile operators) are running out of the capacity needed to deliver it.
The result of this has been that for years the Federal Communications Commission has auctioned hundreds of megahertz of spectrum deemed appropriate for these operations (“mobile-friendly”) to the mobile operators. According to wireless trade association CTIA in their report “Substantial Licensed Spectrum Deficit (2015-2019): Updating the FCC’s Mobile Data Demand Projections” issued on June 23, 2015: “in the past six years, wireless operators have invested over $160 billion and, even with additional spectrum, a similar financial commitment will be necessary to enhance and expand networks to help meet significantly higher data volumes.”
According to the same report, “there is currently 645.5-megahertz of spectrum licensed for broadband,” and “…the U.S. will need more than 350 additional megahertz of licensed spectrum to support projected commercial mobile wireless demand. Accordingly, over the next five years the United States must increase its existing supply of licensed broadband spectrum by over 50%.”
Recent events, however, cast serious doubt on these kinds of claims. The events in question are the recent activities regarding the use of LTE technology in unlicensed spectrum. There are multiple technologies being discussed, from LTE-U to LAA to LWA to Qualcomm’s MuLTEfire. The FCC opened an inquiry (FCC 15-105) to get answers to how these technologies would be able to share spectrum with Wi-Fi and the result has been a vigorous conversation (to say the least) if not broad agreement on the answers. Lost in the minutiae of the back and forth on this topic, however, has been perhaps the most important admission in the recent history of spectrum policy: The mobile operators have admitted publicly that they can run their businesses using unlicensed spectrum.
As debate over this topic has raged, the message from the mobile operator community has been unambiguous:
• In comments to the FCC on June 11, 2015, CTIA wrote “unlicensed LTE technology will combine the spectrum efficiency and quality of LTE’s service capabilities with the spectral capacity and flexibility of unlicensed operations to greatly benefit U.S. wireless consumers … . In particular, applying LTE technology to wide-bandwidth unlicensed bands will greatly increase network capacity.”
• In November 2015, Vodafone reported on their live trial of the LAA technology that “… the test achieved download speeds of over 274 megabits per second by aggregating 20 megahertz of licensed spectrum in the 1800 MHz band and 20 megahertz on the unlicensed 5 GHz band … . This technology will help us to further expand 4G capacity and improve the experience our customers have when using mobile broadband.”
• In May 2015, it was reported “South Korea’s third largest operator LG Uplus has combined LTE in unlicensed spectrum (LTE-U) with existing LTE spectrum to achieve a theoretical download speed of 600 Mbps. The operator used 60 megahertz in the 5.8 GHz band, which traditionally is used for Wi-Fi, and 20 megahertz in an unconfirmed LTE band, the Korea Times reported. LG Uplus said it plans to expand the use of the unlicensed spectrum to 80 megahertz to boost speeds to 750 Mbps and plans a commercial launch once handsets that support the 5.8 GHz band are available.”
• The above are all consistent with statements from companies such as Qualcomm who say with regards to the use of LTE in unlicensed spectrum that “… along with the use of a robust and highly-reliable, licensed anchor for all signaling and control functions, LTE-U and LAA can provide 2x or more capacity … in dense deployments.”
The problem is, however, that mobile operators are trying to have it both ways. On one hand they warn of a spectrum crisis and call for hundreds of megahertz more licensed spectrum for their operations. On the other hand, they tout the capacity gains that can be achieved as they make use of unlicensed spectrum. And yet the impact of the latter is completely unaccounted for as they call for the former. In the CTIA’s report calling for 350 megahertz more spectrum, for example, there is not a single mention of LTE-U, LAA, LWA or MuLTEfire. The only mention of unlicensed spectrum is a reference to the usefulness of Wi-Fi, not to any of the new techniques, which are causing so much excitement in the industry.
For example, when the report states that “moreover, Cisco also estimates that by 2019, twice as much wireless data will be offloaded to unlicensed spectrum as is carried on the macro networks using licensed spectrum,” the footnote to this statement says “Cisco predicts that 66% of U.S. mobile data traffic will be offloaded to Wi-Fi networks in 2019.”
Based on the trials referenced above and the comments from Qualcomm, it is clear the use of LTE in unlicensed spectrum can provide capacity increases of two or more times over what mobile operators can obtain with their current allocations. The tests in South Korea, with 60 megahertz of unlicensed spectrum augmenting 20 megahertz of licensed spectrum imply a capacity improvement of roughly four times, and the plans to expand this to 80-megahertz of unlicensed spectrum would result in about a five-times increase in capacity.
With these kinds of capacity gains, the estimation by CTIA that 350 megahertz more spectrum will be needed in the coming years needs to be seriously re-examined. With unlicensed spectrum augmenting capacity by five times, far from needing an additional 350-megahertz of spectrum, the mobile industry would need as little as 70 megahertz of spectrum, or even less.
The auctioning of spectrum for a use for which it is not needed has many negative side effects:
• Mobile operators are paying for this spectrum and burdening themselves with debt, which makes it hard for them to allocate funds to other things, like expanding their networks, creating and deploying new services, etc.
• End users eventually end up paying for these high costs of spectrum through higher monthly fees.
• The spectrum itself is being set aside for a use for which it is not required and, therefore, diverted from being used for other purposes.
It would be appropriate, therefore, to stop auctioning off every hertz of identifiable mobile-friendly spectrum to the mobile operators based on the outdated belief there is a spectrum crunch, or deficit, which needs to be addressed. Until the effect on the claimed spectrum deficit of the use of unlicensed LTE technologies is adequately explained, no further auctioning of spectrum for mobile purposes should continue.
Even now the FCC is preparing to auction off spectrum in the 600 MHz band “to wireless providers to support 21st century wireless broadband needs.” It seems far from clear, at this point, this is in fact the right way to allocate spectrum for the 21st century. In fact, based on all of the recent evidence, by far the better option might be to start taking all of this mobile-friendly spectrum and to allocate it as unlicensed spectrum so that it can be used not only by mobile operators, but also by traditional unlicensed spectrum users, and also by the new types of operators that will be providing the infrastructure for the coming “Internet of Things.” Dramatically increased unlicensed bands, moreover, will help to alleviate inter-technology interference concerns that are the source of so much angst at the moment.
Whether or not over the long term it even makes sense for the mobile operators to retain all of their current spectrum holdings is an interesting question, which should be considered as this new spectrum use model takes hold. If the licensed bands are needed only for “signaling and control functions” as indicated by Qualcomm, there is perhaps a claim to be made for even less overall licensed spectrum and even more unlicensed spectrum. But for now, at least, it is clear no further allocations of licensed spectrum for mobile operations should be made.
The future of spectrum management has finally arrived. We should embrace it.
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