3.5GHz Innovation Band Becoming Available

Last year the FCC finished its rules for opening up previously restricted spectrum at 3.5GHz to experimental public use. In particular, this now permits commercial operations in 150MHz of new spectrum in the 3550-3700MHz band which was previously reserved for the Defense Department for coastal navigation use, and fixed satellite services. What does this mean for public school districts? A potential new path and service set for mobile data communications. This is another step in the Obama administration’s effort to expand broadband access. However, this depends heavily on what equipment vendors and network operators do over the next few years. 

You may be familiar with the current unlicensed WiFi bands at 2.4GHz and 5.0GHz. There are also several bands of cellular data provided by the carriers at various places between 700MHz and 2500MHz in the US. (In fact, the 700MHz band only became available several years ago when broadcast TV was moved to the new HDTV frequencies.). This new band of frequencies is being opened for sharing and is being called the “Innovation Band” by the FCC. Their hope is that commercial operators will use this band to experiment with new types of wireless services.

So far, however, the key players (carriers and WiFi standards groups) have yet to show a lot of interest in the band. Though it is an unlicensed band, there is a complex three tiered set of use permits needed because it is being shared with the incumbent users, like the US Navy, who have priority use and must be protected. The FCC has set up exclusion zones near incumbents that restrict the new experimental projects. Most of these exclusion zones are near the coasts, however, and not geographically uniform around the country.

The 802.11 Working Group of the IEEE has backed off of specifying any technical standards for this band because of the exclusion issues. LTE operators are also reluctant to add support for this band without the circuits and phones being available. Likewise, equipment manufacturers need commitments from the carriers, creating a chicken and egg problem. 

Where it may take off is in private non-standard WiFi based networks and niche markets. 3.5GHz is sheltered spectrum, free from the interference in the 2.4GHz or 5.0GHz bands. Indeed, Google now has permission to move ahead with a deployment trial in Kansas City, the first large-scale test of its kind. They will be installing microcells on poles in various places in the city to provide a wireless data service. Google is doing exactly what the FCC hoped. There is a strong potential for providing cheaper access for low income residents with such a system. For school districts, off-campus access has often been a stubborn barrier to full transformational implementations of digital learning. 

Over time, the WiFi standards groups and LTE carriers may move in more enthusiastically as the band gains in popularity from initial experimental success. It will be well worth keeping an eye on this new band over the next year or two. If smaller telecom operators and equipment designers take Google’s lead and start playing around in this band, we could have the potential for a new range of services and an incentive for the FCC to continue to make more spectrum available.

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