FCC White Space Order Offers Partial Victory for Wireless Mic Users
By Ken Kerschbaumer
When the FCC chairman and commissioners voted 5-0 on Nov. 4 to allow unlicensed consumer devices to be used in the White Space spectrum sports networks and leagues rely on for wireless microphone and communications systems it appeared to be a stunning setback for wireless users. But after the FCC issued the actual order it is clear that the hardwork of the Sports Technology Alliance, MSTV, and wireless microphone manufacturers like Shure and Sennheiser had an impact.
For example, the FCC did not require wireless microphones to move out of the core TV channels or declare that microphone operations receive no greater interference protection than an unlicensed user. Some proponents of White Space device technology fought hard for those positions and lost on both fronts.
The order laid out a two-pronged vision for how unlicensed portable consumer devices will be allowed into White Space spectrum: via tapping into a geolocation database to find whether or not the device can operate in the area or by relying on spectrum sensing technology to find available frequencies. The devices will be restricted to channels 21-51, regardless of whether they are tied into the database and -114 dBm is the sensing level for all incumbent signals. In fact, the -114 dBm sensing threshold may be adjusted (presumably made tougher) for sensing-only devices. In addition, output power levels of sensing-only devices cannot exceed 50 mW EIRP, regardless of the channel.
“We think the FCC worked pretty hard to incorporate microphone protections into the order,” says Mark Brunner, Shure’s Senior Director, Global Public and Industry Relations. “Our intent is to be actively engaged in the development of sensing-based devices.”
Another hurdle for the White Space device manufacturers is they must first submit an application with a “full explanation of how the [sensing-only] device will protect incumbent radio services” before the device can be put into consumers hands. In addition, a working consumer-grade version of the product needs to pass tests (open to the public) before the device can be released.
Those devices that rely on the geolocation database must incorporate GPS and communicate with an online database that prohibits operation on frequencies previously registered in the database (protection for those frequencies will extend for 1 kilometer). The goal of the database is to keep channels clear (except for channel 37) for wireless microphone use.
The database, however, is in its embryonic stages and it is unclear who will develop it and maintain it. It is expected to be venue driven so, for example, Madison Square Garden would enter events into the database and be able to set aside frequencies for wireless microphone and communication systems needs. Questions, among many, that remain is how frequently will devices tape into the database, how frequently will a master database be updated, and how quickly can the database be changed to reflect real-world and quickly developing situations like a press conference or breaking news event.
“The database does not yet exist and that is an opportunity for professional users to be engaged in defining the operating parameters of the database,” says Brunner. Those details could include what the online interface could look like, database templates, and how the data is captured and updated.
So what is next for White Spaces? The FCC, of course, will consider petitions for reconsiderations or court appeals of some or all of the FCC’s order. In fact, it’s possible those appeals or petitions could come from those on both sides of the issue.
The FCC will also consider proposals to increase the power limits of portable device operation on adjacent channels and also develop an appropriate spectrum sensing test methodology.
Also expect the FCC to choose one or more database administrators and developing further rules and requirements for access to and interaction with the geolocation database.
“Although the introduction of personal, portable white space devices will pose new challenges for wireless mic users, multi-channel operation can be made reliable through the use of quality equipment operated using best practices,” says Joe Ciaudelli, Sennheiser’s White Space spokesperson. To meet those needs Sennheiser has a website /a> dedicated to the top, a help desk hotline, and RF Sound Academy seminars that will educate customers.