Photo by c&rdunn, courtesy of Flickr
FCC engineers will test prototype “White Spaces” devices on Saturday, August 9, at FedExField just outside of Washington, D.C., at a preseason exhibition game between the National Football League’s Washington Redskins and Buffalo Bills. Starting at 10:00 a.m. and continuing through 8:00 p.m. Eastern time, the period of observation and analysis will assess the ability of the proposed devices to detect the presence of television signals, wireless microphones, and other existing wireless technologies.
Seating 91,704 people, FedExField is the largest stadium in the NFL. Of specific interest to the FCC, during this real-world test the stadium will become a very complex and large venue for wireless RF activity including microphones, two-way radios, communication systems used by the coaching staff of each team, and interruptible foldback (IFB) intercoms used by broadcast crews.
“It’s really the perfect environment for what the FCC is trying to accomplish,” says Shure’s director of advanced development, Edgar Reihl, who, along with other engineers at Shure Inc. in Niles, Ill., helped develop the FCC’s test standards and secure the use of FedExField for testing. “This is definitely the place where real-world conditions exist to the extreme. When testing is complete, we should have a much clearer view of whether or not this proposed technology can operate without interfering with other necessary services and uses that are ongoing.”
Reihl will be on-hand at the August 9 event, along with others from Shure Inc., one of the world’s largest manufacturers of wireless microphones and other wireless systems. Prototype technologies intended for possible use in the White Spaces are being submitted by two entities: electronics company Philips and Singapore’s Institute for Infocomm Research (I2R), a government-sponsored agency dedicated to science, technology and research.
“The proposed devices will be subjected to receiving tests only,” Reihl explains. “In terms of wireless microphone activity, they will attempt to detect their presence accurately and consistently in different locations throughout the stadium, at times before and during the game. This is a particularly difficult thing to do when there are other strong signals in the air, like those generated by digital television transmission. Wireless microphones occupy spaces alongside and in between these powerful HD signals.”
The first step in obtaining harmony in the White Spaces frequency spectrum is reaching a point at which the new prototype technologies are capable of accurately and consistently detecting the presence of wireless microphones and other wireless devices while in use. According to plans envisioned by proponents of the new proposed devices, after the technology is able to sense an occupied frequency, it should then be capable of moving away from that channel to an open one without causing any interference. Conversely, if one of the proposed devices is in use on an unoccupied channel and senses that a wireless microphone or other existing device is attempting to use the same frequency, it would automatically move away from that one and on to another open frequency.
Reihl believes that one of the most important facets of the testing is to determine the accuracy of the detection capabilities inherent in the prototype devices. One of the issues that was encountered in laboratory testing was that sometimes the devices detected that a channel was in use when it actually was not (a false positive), and not in use when it was (a false negative).
“Accuracy in detecting is vital,” he adds, “because if the devices post a series of false positives that stop them from working repeatedly, users are going to be strongly motivated to devise ways to defeat that protective circuitry.”
As a way of better determining the accuracy of the prototypes’ detection capabilities at FedExField, the FCC will begin by testing the devices with all wireless microphones switched off, then move to tests with them switched on. The results of this scenario will obviously reveal a telling number of false positives should they occur when the wireless microphones are turned off.
“We want the science to speak for itself here,” Reihl says. “We applaud the FCC for taking the initiative to test this proposed technology under the extreme real world conditions this preseason football event will afford. This is the best way to reach a level of understanding that will help us all achieve reliable interference protection.”
Following on the heels of the Redskins/Buffalo Bills game testing at FedExField, the FCC will continue its field analysis on Broadway in New York City at the Majestic Theater during the week of August 11.
“We look forward to watching all of these tests closely,” says Mark Brunner, Shure’s senior director of public and industry relations and one of Reihl’s colleagues who is also slated to be at FedExField on Saturday, August 9. “It’s imperative that we understand what works and what doesn’t before we commit to a situation that can’t be reversed.”
For more information from Shure about “White Spaces” and links to other “White Spaces” Websites, visit Shure’s Website.