Verizon and Google don’t always see eye-to-eye when it comes to the millimeter wave bands. For example, Verizon would rather not see sharing models like the one for 3.5 GHz adopted for millimeter wave bands, while Google would like to see sharing considered for, say, the 24 GHz band. But when it comes to the 70-80 GHz bands, Verizon says Google’s got the right idea.
Namely, Google argues that the FCC should retain the existing light licensing framework that is working well today for the 70/80 GHz bands, rather than adopting a three-tiered architecture managed by a spectrum access system (SAS) as the commission has proposed. Google has been an active participant in the development of an SAS framework for the 3.5 GHz band, also known as the Citizens Broadband Radio Services (CBRS) spectrum.
“Google’s proposal for generally continuing a ‘light-licensing’ approach for the 70-80 GHz band would be preferable to a complex experimental SAS regime that could risk harming existing backhaul operations and deterring future ones,” Verizon wrote in an Oct. 31 filing with the FCC (PDF). “The Commission should consider Google’s proposal to modify the 70-80 GHz band’s existing regime to add point-to-multipoint operations. Verizon looks forward to details about how that proposal would work, including the proposed coordination and registration regime for clusters of links, and the respective interference rights and obligations of operators registering different types of operations in the band.”
In a September 30 filing (PDF), Google said maintaining the existing rules, with updates to the registration parameters and minimum antenna gain for the band, is a straightforward and minimally disruptive approach for the 70/80 GHz band. More than 400 licensees collectively have registered “tens of thousands” of links in the bands, and new entrants can readily participate in the registration process, Google said, noting that Google and Google Fiber have first-hand experience with the current regime, having registered 70/80 GHz links for diverse purposes ranging from the retail wireless broadband service of Webpass to developing Project Loon’s balloon-powered internet access technology.
Millimeter wave stakeholders including Verizon and Google are among those weighing in as the FCC collects another round of comments on its Spectrum Frontiers proceeding that seeks to solidify rules around the use of spectrum bands above 24 GHz for mobile radio services. As it did in prior comments to the commission, Verizon is urging regulators to establish traditional licenses for certain bands with reasonable terms and relatively large service areas. Any sharing mechanisms should be avoided, in particular for the priority 24, 32 and 42 GHz bands, according to Verizon.
In its latest comments (PDF), Google reiterated that the 70/80 GHz bands should largely retain the existing regulatory framework. “The current rules offer relatively barrier-free access to spectrum and are well tailored to the physical characteristics of these bands, which better support fixed point-to-point operations than wide-area mobile service,” Google said.
As for the 24 GHz band, it’s better suited for a range of small-cell mobile applications, Google said. It offers propagation characteristics better suited to mobile operations but also has exceptional reuse potential due to high building loss and other sources of attenuation.
“Thus, while area licenses are appropriate in this band, they should be small in size. This band could also be a good candidate for deployment of Spectrum Access Systems (SASs) to further increase efficiency,” Google said in the Oct. 31 filing.
Verizon has different designs for the 24 GHz band. “Any sharing experiments should be limited (avoiding, in particular, the priority 24 GHz, 32 GHz, and 42 GHz bands), and should provide the certainty needed by operators deploying networks with high reliability requirements,” Verizon stated in the Oct. 31 filing.
“Some parties simplistically assert that the 3.5 GHz band’s complex Spectrum Access System (‘SAS’) can be readily imported and successfully implemented in mmW bands – both in the new bands proposed in the FNPRM and in the lower portion of the 37 GHz band. Not so. Verizon supported the Commission adopting a SAS in the 3.5 GHz context to address government incumbents’ protection requirements, but only time and experience will tell if it will prove capable of supporting the same level of investment and innovation encouraged by more traditional licensing frameworks,” Verizon wrote.