Sharing Urged in 42 GHz Band, Though Disagreements Emerge on Details

Wireless carriers don't have much apparent interest in the 42 GHz band, to judge from comments posted Thursday in response to a June NPRM on potential sharing in the 42 GHz band. New America’s Open Technology Institute and Public Knowledge were enthusiastic about the possibilities. Comments were due Wednesday in docket 23-158.

The NPRM asks about three potential approaches in the band -- nationwide nonexclusive licensing, site-based licensing and technology-based licensing (see 2306080042). It also proposes to license the band in five 100 MHz channels.

“We continue to believe that in this millimeter wave band ... a framework premised on open access, licensing by rule, and automated database coordination will best serve the public interest,” said New America and PK. “Such a sharing framework will be especially beneficial if it can be used to coordinate local access for a diversity of users and use cases across both the 42 GHz and the Lower 37 GHz bands, thereby facilitating far greater flexibility and capacity,” they said. The group urged a similar approach in the lower 37 GHz band.

The public interest groups proposed sharing based on automated frequency coordination (AFC), which will soon be used in the 6 GHz band (see 2308250061), with a license-by-rule framework similar to the general authorized access tier of the citizens broadband radio service band. “It’s likely that one or more of the certified 6 GHz AFC systems could be adapted quickly to manage access and minimize interference in these bands, avoiding years of delay,” they said.

T-Mobile conceded that the band’s technical characteristics, “along with its separation from other millimeter wave spectrum that has already been licensed,” mean exclusive-use licenses may not be appropriate in 42 GHz. But the FCC “should avoid applying untested, novel sharing approaches,” T-Mobile said: “Instead, it should implement the nationwide non-exclusive licensing framework currently used in the 70/80/90 GHz bands, with a few modifications to ensure that the spectrum will be used efficiently and may be deployed for variety of advanced communications services.” Comsearch largely agreed with the approach advocated by T-Mobile. “The 70-90 GHz registration framework was established nearly two decades ago” and is “simple and successful,” Comsearch said.

NCTA urged the FCC to consider fixed and mobile sharing, including with federal users, in the lower 37 and 42 GHz bands. The FCC should “grant nationwide, non-exclusive licenses to qualified applicants, who could request to operate in any or all of the channels available” in the bands, NCTA said: The agency should also “require licensees to register their links and/or base stations with one of several third-party database administrators named by the Commission.” Other approaches, including a sharing framework based on sensing “would introduce another unnecessary layer of complexity and potential cost,” cablers said.

Charter Communications also supported the granting of nonexclusive licenses, though its comments focused more on 37 than 42 GHz. Charter noted gear is already available for use in the former band. “With the right allocation framework, the high-path loss features that characterize the Lower 37 GHz band can create an opportunity, not a challenge: these frequencies enjoy high frequency reuse since numerous small transmitters can operate independent of one another given the limited range of each transmitter, which reduces interference between adjacent cells,” Charter said.

Federated Wireless urged sharing, controlled by a dynamic spectrum management system (DMMS) in both bands. “As is the case with sharing frameworks that have successfully been implemented in other bands, using DSMS technology would provide for modernized frequency coordination and band access management between and among incumbent and prospective users, implement incumbent protection criteria, and facilitate access to both bands by a wide range of new users, with all of these functions performed in real time,” Federated said. The Dynamic Spectrum Alliance also urged sharing used DSMS.

The Wireless ISP Association supported sharing using AFC but with a twist. “The AFC should be more like an automated version of the 80 GHz coordination process rather than a copy of the 6 GHz AFC,” WISPA said: “At 6 GHz, the AFC indicates which frequencies are available each day, but does not keep track of actual usage or protect users from each other. At 80 GHz, holders of a nationwide license coordinate links via a frequency coordinator.” WISPA said wireless carriers should be excluded from using the band.