FCC Office of Engineering: Prototype Portable Consumer Devices Fail Test
By Ken Kerschbaumer
The battle over whether or not to allow unlicensed portable consumer electronic devices into broadcast spectrum currently used by sports leagues, teams and broadcasters heated up last week when the FCC’s Office of Engineering and Technology reported in its initial evaluation of prototype devices that they performed miserably compared to the promises of interference-free use.
“White Space devices submitted to the Commission for initial evaluation do not consistently sense or detect TV broadcast or wireless microphone signals,” said the report. “Our tests also found that the transmitter in the prototype device is capable of causing interference to TV broadcasting and wireless microphones.”
Adding insult to injury, the FCC’s OET said any additional testing is not deemed appropriate at this time. Across the board both prototype devices (one from Microsoft and another from Philips) caused interference with over-the-air DTV reception and also wireless microphone and other devices.
“The bottom line is this is one battle in a much longer war,” says Dave Donovan, MSTV president. “It demonstrates scientifically that these unlicensed devices are unable to detect broadcast signals and wireless microphones and if deployed they will cause massive amounts of interference.”
Donovan adds that while the results are tough to ignore however it is clear that Microsoft and the White Space Coalition will not give up. “There is no doubt that they will use their political influence to continue this process to eventually allow devices in the band,” says Donovan.
Donovan urges all sports entities to send a letter to the FCC, Congressmen and Senators letting them know that allowing the devices into the White Space band will impact day-to-day business. “Now is the time to urge the FCC to not allow unlicensed personal portable devices in the TV band,” he adds.
Making voices heard is even more important as the testing showed that the auto-sensing solution proposed by the White Space Coalition is, at this stage, an empty promise. Auto-sensing technology in prototype A (the Microsoft unit) took approximately 27 seconds to scan each broadcast channel and about 14 minutes to scan the full range of 31 channels that it covers. Prototype B (the Philips unit) required 8 minutes to scan the full range of frequencies.
But even with those delays, which at least imply a level of thoroughness, prototype A was “generally unable to sense wireless microphones.” Prototype B was able to sense wireless microphone signals located in the center of the TV channel in all scans at a signal level as low as-120 dBm. The devices ability to sense wireless microphones decreases as the location of a microphone signal moves closer to the edge of the TV channel.
“What this means it that we’re about to enter a long process where the White Space Coalition will continue to come back to the FCC with the ‘new and improved’ generation of device.”
And despite the overwhelming technical evidence Donovan says the FCC in October could reach a decision to allow the devices into the spectrum. “They could very well say the initial devices failed but this is still a good idea,” he adds. “So this fight isn’t over. But now that the White Space Coalition is back on their heels the industry needs to give them a push.”
For a complete copy of the FCC report click here.