Study disputes predictions of coming spectrum crunch

Mobile traffic growth has often been slower than predictions by several analysts, the paper says

Widely accepted projections of a shortage of mobile spectrum may not be as dire as many analysts in the mobile and tech sectors are making it out to be, according to a new study.

Projections on the growth of mobile spectrum use in recent years have often overestimated the demand, with a growing use of Wi-Fi to offload mobile data traffic contributing to inaccuracies, according to the paper, released this month by University of Southern California doctoral candidate Aalok Mehta and Goldin Associates managing director J. Armand Musey.

The paper, distributed but not paid for by mobile spectrum auction critic the National Association of Broadcasters, questioned the prevailing assumption in the mobile industry that there's a coming spectrum crunch, with multiple studies by Cisco Systems, Coda Research, the International Telecommunication Union and other analysts predicting a skyrocketing demand for mobile spectrum.

Although a coming spectrum crunch is "now taken almost as a matter of faith among telecommunications experts," many spectrum use predictions have had "persistent errors," the paper said.

"Our findings suggest the mobile industry contains much higher levels of inherent demand uncertainty than is commonly estimated and that business and governments may not be fully factoring it into their policy decisions," the study's authors wrote.

One major problem, the study said, is that government officials have used mobile spectrum use estimates to push for policy changes. The U.S. Federal Communications Commission and White House have both called for a transfer of 500MHz of spectrum to commercial mobile uses in the coming years, with both government entities apparently using mobile spectrum use estimates by Cisco and other analysts, the study said.

"When spectrum demand forecasts are inaccurate, governments may make inappropriate policy decision," the paper said. "Overestimating the growth of mobile network traffic crowds out other types of wireless communication by increasing spectrum scarcity."

For example, the FCC, in its 2010 National Broadband Plan, used estimates by Cisco, Coda and the Yankee Group to predict a need of an additional 500MHz of mobile spectrum by 2020. While mobile traffic has grown every year since then, it has been significantly lower than the demand forecasts, the paper said.

As another example, the FCC predicted mobile traffic growth of 103 percent in 2012, but actual growth was 69 percent, the paper said.

Representatives of Cisco, the ITU and the Yankee Group didn't immediately respond to a request for comments on the study.

The FCC estimated then that the offload to Wi-Fi and other networks would consistently be about 15 percent of mobile traffic, but it has been above 40 percent since 2012, the paper said.

The NAB, which filed a lawsuit this week challenging the FCC's rules for an upcoming auction of television spectrum, said the study pokes holes in the assumption of an upcoming spectrum crunch.

"No one denies the growth in mobile broadband," said Dennis Wharton, the NAB's executive vice president for communications. "The question is whether there is a crisis, which was the hysteria narrative that led to issuance of the National Broadband Plan and passage of the TV spectrum auction legislation."

The study questioned the objectivity of many of the groups predicting spectrum shortages. "The analysts who create spectrum demand estimates are typically wireless industry veterans who are usually dependent on the industry for their livelihoods," the study said.

The same criticism could be levied at the NAB for distributing the study, critics said. The study appears to "guess" at mobile usage in 2013, instead of using real-world numbers, said Scott Bergmann, vice president of regulatory affairs at mobile trade group CTIA.

"As every other study by well respected and independent organizations have shown over the last few years, there is a significant increase in consumer demand now for mobile broadband and this will only continue to grow exponentially as long as the U.S. wireless industry has access to more spectrum," Bergmann said by email. "This latest from NAB is a tired and disproven distraction."

Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's email address is grant_gross@idg.com.

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