Public safety: 700 MHz spectral flexibility not wanted
On the surface, the notion of providing public-safety entities with the flexibility to use 700 MHz spectrum currently dedicated to narrowband might seem like a reasonable request. After all, who doesn’t like flexibility and choice, particularly when the topic is a finite resource such as wireless airwaves?
Public safety and many other influential organizations, including the “Big 7” government groups and the Telecommunications Industry Association, based on the comments filed in the FCC proceeding exploring the possibility of providing first-responder agencies with flexible use of the 12 MHz of 700 MHz narrowband spectrum.
Overwhelming, commenters have expressed opposition with the notion of flexible use of the narrowband airwaves, citing myriad reasons, from concerns regarding interoperability channels to the potential of public safety experiencing the same kind of interference between intermingled broadband and narrowband systems that happened between LMR networks and Nextel in the 800 MHz band. Others note that flexible use would just create more confusion and uncertainty in the 700 MHz narrowband market.
In addition, many in public safety have opposed the notion of flexible use because many believe that a potential flexible-use rulemaking could be perceived as an alternative to reallocating the D Block to give public safety the 20 MHz of contiguous spectrum it wants for the proposed nationwide broadband network for first responders.
Of course, the problem with this notion is that the public-safety spectrum shortage tends to exist in the more populous areas, most of which already have implemented—or are in the process of deploying—700 MHz narrowband systems, so the existence of an FCC flexible-use ruling would have little practical benefit for the foreseeable future.
Perhaps more importantly, the fact that there are no plans to have mission-critical voice as part of the LTE broadband standard for years to come mean that a flexible-use order would not help address public safety’s most pressing need.
Can mission-critical voice be realized over LTE? Technically, it can be done, based on the discussions I’ve had with engineers on the subject. However, it could be some time before this comes to fruition, because vendors and standards bodies are expected to focus their resources on developing solutions for much more lucrative commercial markets before attempting to tackle mission-critical voice applications for the smaller public-safety market.
When the mission-critical voice is developed for LTE — whether it is five years or 50 years from now — the FCC would be justified in revisiting this topic, because governments would prefer to have all of their wireless communications being transmitted over a single broadband network, instead of supporting a voice network and a data network.
At that time, an FCC proceeding should focus on the best way to migrate all public-safety communications to a broadband platform supported by about 40 MHz of almost-contiguous spectrum in the upper 700 MHz and lower 800 MHz band — a tremendous spectral foundation that public safety deserves. However, until it is clear that mission-critical voice over LTE is a viable choice for first responders, such a proceeding would be premature.
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