Carriers Say 12.7 GHz Band Offers Some Potential for 6G

Wireless carriers see the 12.7 GHz band, also known as the 13 GHz band, as a candidate for reallocation for 5G, and eventually 6G, based on comments filed last week at the FCC. But carriers consider the band in general inferior to 3.1 GHz and other bands with less packet loss and better propagation characteristics. Broadcasters, the satellite industry and NTIA also raised concerns.

The 13 GHz band "seems sufficiently unconstrained that it will be a good test case for the current commission's theory of spectrum allocation and its priorities for the wireless economy,” said Joe Kane, Information Technology and Innovation Foundation director-broadband and spectrum policy, Monday. “There are enough incumbents” the FCC will have to account for “either by technical protection or relocation, but there are few enough that the commission can take its choice of access regimes for new entrants,” he said.

The satellite industry's skepticism of flexible-use rules “will test the extent to which terrestrial mobile and satellite service are becoming really complementary,” Kane said: “The choice between exclusive licensing and sharing will reveal what the commission thinks about the state of sharing technology.”

“The upper 12 GHz band holds great promise,” said Cooley’s Robert McDowell. “While it is a bit encumbered it could still be put to productive use for consumers and America’s mobile tech economy. Its auction yield might be more akin to millimeter wave than, say, C-band,” he said: “But Congress could look at it as a nice piece of revenue going forward. It’s one of the few large pieces of spectrum the FCC could try to auction if it gets its auction authority restored.”

CTIA supported reallocation, but without extensive carve-outs and at power levels that make deployment practical. CTIA estimated 13 GHz deployments may require nine to 30 times more sites than the C band, now being deployed by carriers. There's also “work to do” to make the band “a reality, including significant standards work and the development of international harmonization through the World Radiocommunication Conference process,” CTIA said.

CTIA urged the FCC to support more extensive mobile use of the spectrum at the upcoming WRC-23 and creation of a new agenda item for WRC-27 “proposing study of spectrum below 15.35 GHz for new identifications” for international mobile telecommunications. “While 13 GHz will play a role in supporting the capacity needs of wireless providers, there still is an urgent need for additional mid-band spectrum to support the growing coverage and capacity needs of wireless consumers,” the group said.

“Prioritize repurposing the lower 3 GHz band first, followed by other low mid-band ranges for flexible-use commercial licenses,” 5G Americas advised.

The propagation characteristics of 13 GHz “mean that it is not truly mid-band spectrum offering a prime combination of coverage and capacity,” Ericsson said. The band “presents challenges for deploying coverage across outdoor areas and deep within buildings in comparison with spectrum at lower bands,” the company said: “Nonetheless, with the right technical rules -- higher transmit power levels, in particular -- the 12.7 GHz band can serve an important role for 6G.”

Nokia sees promise for the band. “Technological advancements like larger antenna arrays and higher antenna gains with narrower beams can overcome some of the fundamental challenges of this band,” Nokia said: “Larger operating bandwidth and higher equivalent isotropically radiated power limits can bring system performance of this band closer to C-band deployment.”

Limitations

Verizon saw potential but also warned of limitations. “Although the 12.7 GHz band has more significant propagation loss characteristics as compared to prime mid-band spectrum and standards development is not yet underway for the band, Verizon is nonetheless supportive of the Commission’s proposal to identify the 12.7 GHz band for licensed, exclusive operations on a flexible-use basis to support advanced connectivity,” it said. The FCC should “pursue technical rules that support wide-area deployments, including a higher permitted power level than proposed” and adopt proposals on the relocation and protection of incumbents, Verizon said.

AT&T said 13 GHz isn’t as well suited to 6G as bands in the 3-8 GHz range. While the FCC’s NPRM on the band says “6G standardization efforts are underway, they are nascent,” AT&T said: Ideal band and channel block sizes, use cases, power levels “and other key technical parameters for 6G are still being considered. [3rd Generation Partnership Project] driven 6G requirement work is not expected to commence until 2024 and Phase 1 of standardization as part of 3GPP Release 20 is not expected until 2026.”

“The 12.7 GHz band can become an important part of providers’ spectrum portfolios to support next-generation wireless technologies, including 5G, 5G Advanced, and 6G services,” T-Mobile said: The band can “support the high data rates and provide the reliability, low latency, and capacity on which those technologies rely.”

As with nearly all spectrum bands, some incumbents are raising reallocation concerns. NAB said all broadcast auxiliary services can't be moved elsewhere (see 2308090061). Satellite interests urged allowing more use of the frequencies by that industry (see 2308100048). NTIA sought protection for some federal systems (see 2308110037).

“Broadcasters and, consequently, the public currently rely on both fixed and mobile broadcast auxiliary services in the Band,” said the Society of Broadcast Engineers. “Fixed uses include essential signal delivery paths -- both primary and backup -- without which critical information might not be delivered and broadcast to the public,” SBE said: Mobile uses include “electronic newsgathering that enables on-the-spot reporting, ranging from coverage of a local parade to collecting and communicating time-sensitive emergency information.”

Broadcasters hold fewer than 2,000 licenses in the 12.7 GHz band and are open to plans that involve repacking many of them, but proposals that would require moving all of them or sunsetting broadcaster use of the band likely aren’t feasible, said Robert Weller, NAB vice president-spectrum policy legal and regulatory affairs. Broadcasters use the band primarily for the links between their studios and their transmitters, “the most critical link,” Weller said. “Loss of those links would be the end of TV stations' ability to broadcast.” Broadcast industry officials told us they believe the agency will be responsive to their concerns and hold broadcasters harmless if a repacking is required.

If the FCC compensates broadcasters for repacking costs, it should do so in an expansive way that leaves room for companies to make technology upgrades that might be needed for them to operate in a tighter, repacked band said Brooks Pierce attorney Patrick Cross, who represents SBE. Repacking would have to be considered on an individual market basis, in part because broadcaster use of the band is largely concentrated on the coasts, Cross said.