* Crush of mobile devices can slow Internet traffic
* Move would open some airwaves used by government to public (Adds background)
By Alina Selyukh
WASHINGTON, Feb 20 (Reuters) - U.S. regulators on Wednesday proposed to free certain slices of airwaves in an ongoing effort to tackle the shortage of available wireless spectrum, a move that could ease Wi-Fi congestion in airports, stadiums and other high-use hubs.
The Federal Communications Commission's proposal would open for public and private use some of the airwaves largely used by government entities, including the Department of Defense and the Federal Aviation Administration.
More spectrum - airwaves used to transmit wireless signals - would mean better connections in homes as well as at convention centers, stadiums, airports and other places where large numbers of devices are used to access the Web at the same time.
At present, a crush of users can slow Internet traffic to a frustrating crawl - a phenomenon well known to business travelers and others. It has made spectrum crunch one of the top priorities of the FCC and technology leaders in U.S. Congress.
The FCC and the telecommunications industry have warned of a looming shortage of spectrum that could hurt the quality, speed and coverage of U.S. data connection services.
The new proposal, approved unanimously, would add 195 megahertz of unlicensed spectrum to the 555 MHz currently available in the less-congested 5 gigahertz radio frequency band. In the past, new unlicensed spectrum led to innovations such as cordless telephones and remote garage-door openers.
The FCC's new proposal now also seeks better technical rules for spectrum-sharing by federal, commercial and private users.
A government review of the 5 GHz band, completed in January, raised concerns about risks of interference posed by such shared use of the spectrum to federal programs occupying it now.
Authored by the National Telecommunications and Information Administration, the FCC's counterpart that oversees government-used airwaves, the review called for more testing that could last through 2014 to ensure no federal missions would be hurt.
The FCC's move also raised red flags in the auto industry, though, which worries about interference with new technology relying on the 5 GHz band, such as self-driving cars and systems that help avoid accidents.
President Barack Obama has directed the FCC and NTIA to greatly expand the commercial use of the government-controlled spectrum over the next decade as a rising number of devices and programs rely on such connections.
FCC Chairman Julius Genachowski on Wednesday said he did not foresee a need to backtrack on sharing of the requested frequencies and hoped that current users and the commission could consult and come up with solutions to make it work.
"This proposal today is based on a tremendous amount of engineering work," he said. "So we don't now see any reason why we can't put 195 new megahertz of spectrum for unlicensed use on the market and do it in a way that's compatible with other existing users."
The FCC will now collect comments on the proposed rules before finalizing them. Analysts forecast the process would take months and maybe over a year, given the interference concerns, which the NTIA reiterated in a letter to Genachowski on Tuesday.
In a statement, NTIA Administrator Lawrence Strickling welcomed the FCC's "comprehensive approach" to resolving the issues related to sharing of airwaves.
Similarly, Scott Belcher, chief executive of the Intelligent Transportation Society of America that includes automakers and suppliers, cautioned "against putting near-term life-saving innovations like connected vehicle technology at risk in the pursuit of future Wi-Fi applications". (Editing by David Gregorio and Dale Hudson)