Twelve Comments and six Reply Comments were filed this month in the 800 MHz Interstitial proceeding, Docket 15-32. Most commenters supported the concept so long as incumbent licensees were protected from harmful interference. Permitting the introduction of interstitial channels operating on frequencies inserted at 12.5 kHz offset the existing 25 kHz 800 MHz “Interleaved” or “Mid-band” frequencies could provide much-needed spectrum relief in certain areas, particularly for non-PS applicants who are not able to file for spectrum vacated by Sprint Nextel until that spectrum reverts to its original allocation pool.

In general the commenters supported a maximum bandwidth of 11.25 kHz on the interleaved frequencies, primary operations, allocating the interstitial frequency to the pool of the lower adjacent and supported the concept of LMCC’s proposed technical matrix for coordinating interstitials against various technologies.

A few comments completely opposed the proposal, urging the Commission to abandon the proceeding calling it a step backward. Some commenters worried that the coordination matrix proposed by LMCC would be either too stringent to provide any spectrum relief or would be untenable in the real world.

UTC and a few utilities urged the FCC to license the interstitial frequencies only on a secondary, non-interference basis. Commenters also sought ways to protect the interests of incumbents such as establishing a one-year filing window during which only incumbent licensees could file for the interstitials and protecting all incumbents as though licensed for 22 kHz operations.

In Reply Comments, the LMCC provided an updated coordination matrix intended for use by its member frequency advisory committees but not meant to be included in the FCC’s Part 90 rules. The FCC will review the comments provided in the proceeding and determine whether or not to pursue the idea.