|
Mobile & Wireless
FCC okays white space spectrum for wireless service
Opens new frequency range but faces concerns over broadcast interference
by Doug Allen
As most observers predicted, on Nov. 4 the FCC voted unanimously for a proposal to allow unlicensed wireless devices to access so-called “white spaces” found in the spectrum band normally allocated to TV transmission. These white space frequencies can be used to deliver a variety of mobile broadband services over previously untapped spectrum range, as mobile traffic growth continues to surge and occupy more and more of the airwaves. The result of lobbying efforts spearheaded by Google, Microsoft and Motorola, these new broadcast capabilities are expected to pave the way for mobile operators to target more subscribers in both urban and especially rural areas.
In the same breath, the FCC decision calls for the prior establishment of key measures to eliminate a prime source of concern to cable operators and broadcasters, even wireless microphone manufacturer Shure: the issue of frequency interference from competing signals. Indeed, the FCC referred to its initial approval as a first step only to deploying services contingent upon proper protection for already licensed broadcast service carried in the TV bands.
Before going online, the FCC has mandated all white space devices, which are required to support spectrum-sensing technology, must go through laboratory testing in real-world environments to make sure they do not interfere with already-licensed services. The FCC has pledged to “closely oversee and monitor” use of these devices.
For instance, the FCC is calling for implementation of a database that registers all available TV bands. Portable and fixed line white space devices will access this database to find unused white space spectrum before transmission begins. Mobile white space devices will use a geo-locations service that locates available TV bands at a given site.
This strategy can only work though if both licensed and unlicensed devices are registered to the database, and working out the details for a system of compliance remains a work in progress. FCC Commissioner Deborah Taylor Tate voted for the proposal but voiced some reservations about the mechanism for dealing with interference complaints, which called “vague.” She asked to include protections against interference that prevent white space devices from broadcasting too close to where cable head ends are designated and/or located.
As an example of managing competing broadcasts, the FCC gave this example in its release on the decision: “Wireless microphones will be protected in a variety of ways. The locations where wireless microphones are used, such as sporting venues and event and projection facilities, can be registered in the database and will be protected in the same way as other services.”
Going forward, the FCC board wants to establish a certification and authorization program that will monitor compliance with FCC standards through lab testing. Enforcement of those measures has not yet been addressed. In addition, the FCC has scheduled a Notice of Inquiry to consider the impact and best practices for high-power unlicensed white space device operation in rural areas.
|
