Wireless industry group CTIA on Thursday urged the FCC to finalize rules for 3.5 GHz spectrum this summer.

Meredith Attwell Baker, the group's president and CEO, wrote in a letter to the commission that the FCC meeting in July should also include a proposal to auction 70 MHz of that spectrum — known as the Citizens Broadband Radio Service — in 2019.

Those steps, along with previously announced plans to begin crafting rules for the 3.7 GHz to 4.2 GHz band, would help address the nation's "international deficit with respect to mid-band spectrum availability," Baker wrote.

She noted the U.S. ranked sixth in mid-band availability out of 10 nations included in a recent 5G readiness study. The letter added that China has already released 100 MHz of spectrum in the 3.5 GHz band to each of its major carriers, while South Korea and Japan plan to issue more mid-band spectrum next month and next year, respectively.

"The 3.5 GHz band will be the first mid-band spectrum available for commercial use, and it is critical that as much of that 150 megahertz of spectrum as possible is available for licensed use optimized for mobile broadband services," Baker wrote.

The letter indicated that CTIA continues to support balancing general access in the CBRS band with a spectrum sharing initiative. CTIA and fellow industry group CCA have proposed increasing the license terms and geographic reaches in part of the band.

Baker also urged the commission to set an aggressive timeline to clear "hundreds of megahertz" between 3.7 GHz and 4.2 GHz, as well as establish a plan for future spectrum auctions.

"It is imperative that the commission not miss this critical 5G opportunity," Baker wrote.