Regulatory clarity needed for 700 MHz narrowband spectrum

With so much attention being paid to the earliest 700 MHz public-safety LTE networks that will become part of the FirstNet system—for instance, the recent launch in Adams County, Colo.—it is sometimes tempting to forget that the overwhelming first-responder use of the spectrum in the band still supports narrowband LMR communications.

However, that is the case, as there is no question that there are several times more narrowband 700 MHz networks deployed than public-safety LTE systems. There also is little question about what needs to happen to these systems on two important regulatory fronts—relocating existing systems and addressing narrowbanding obligations—but it is important that these items get resolved as soon as possible.

From the standpoint of relocation, some of these LMR systems need to be moved from their current spectrum—now allocated for public-safety broadband and licensed to FirstNet—to public-safety narrowband airwaves. Because the 700 MHz narrowband systems are relatively new, the software-centric relocation process should be much simpler than 800 MHz rebanding.

But the job still has to be done. The good news is that FirstNet has hired former NTIA official Lance Johnson as its director of regulatory strategy. While at the NTIA, Johnson worked with officials from the former Public Safety Spectrum Trust (PSST)—the previous licensee of public-safety broadband spectrum—on the matter, so he is familiar with both the need and the scope of the situation.

The other regulatory cloud hovering over 700 MHz narrowband systems involves FCC rules that call for these networks to migrate to 6.25 kHz channels in an effort to promote spectral efficiency. According to current FCC rules this narrowbanding effort would be completed for all existing systems by Jan. 1, 2017, and any new systems built after Jan. 1, 2015—a deadline that is just six months away—also must meet the 6.25 kHz channel equivalency.

Although the 700 MHz narrowbanding rules remain in place, the FCC already has granted substantial waivers that extend the narrowbanding compliance period until 2024.