(Adds FCC chairman's comment)
WASHINGTON, March 28 (Reuters) - Two television stations in Los Angeles that tested sharing radio frequencies found it technically viable, they said on Friday in a report to federal regulators who see the practice as one way to free up more airwaves for wireless broadband.
Supported by the wireless industry group CTIA, public broadcasting station KLCS and multilingual station KJLA tried channel-sharing, in which they tested how many broadcasting streams can be combined onto one radio-frequency channel, possibly allowing the stations to give up some of the airwaves they now occupy.
The experiment, approved last month by the Federal Communications Commission, "clearly proved channel sharing is feasible, and is a technically viable option for broadcasters with minimal impact for viewers," the CTIA and the stations said in the report.
Channel sharing has been supported by the FCC as a potential way to clear up more airwaves, or spectrum, for a spectrum auction currently scheduled for 2015.
FCC Chairman Tom Wheeler on Friday called the test's results "a compelling case for channel sharing."
"In business, it is very rare to be able to have your cake and eat it too," he said. "It is my hope that broadcasters closely study the channel-sharing pilot project report as they consider the once-in-a-lifetime opportunity offered by the upcoming incentive auction."
In the auction, TV stations would voluntarily give up control of low-frequency airwaves they now occupy so that the frequencies could be sold to wireless providers such as AT&T Inc or T-Mobile US. The wireless companies are keen to boost the strength and reach of their networks as consumers increasingly rely on wireless phones for data-heavy uses like streaming video.
The auction proceeds would reimburse the broadcasters and help fund a new U.S. public safety network.
The National Association of Broadcasters, or NAB, has voiced concern about various aspects of the auction, including the uncertain impact of the rearrangement of frequencies after they change hands.
The FCC has promoted channel sharing as a way for TV stations to sell their airwaves in the auction without leaving the broadcasting business. But NAB has argued that surrendering airwaves may hurt broadcasters' potential to innovate.
"On a technical level, one of the main challenges to channel sharing concerns the ability of the sharers to offer new and innovative services as they are limiting their available spectrum," NAB spokesman Dennis Wharton said when the channel-sharing pilot was proposed in late January.
"On the business side, there are difficult contractual provisions that would need to be addressed."
The experiment by KLCS and KJLA tested only technical details of channel sharing, but not legal or practical issues that may come up for stations that decide to share radio-frequency channels, the report said.
The two stations, which have not committed to participating in the FCC's spectrum auction, tested combining different numbers of high-definition (HD) and standard-definition (SD) program streams on to one six-megahertz radiofrequency channel.
They found it may be technically possible to combine up to three HD streams; two HD streams with up to two SD streams; and one HD stream with up to seven SD streams.
"Our collaboration with KLCS yielded extremely valuable and interesting data about the promise of channel sharing, without adverse effect on our over-the-air audience," said Francis Wilkinson, KJLA vice president and general manager.