Spalter: Spectrum sharing and the elusive silver bullet

Jonathan Spalter

Jonathan Spalter

With more mobile subscriptions than people today in the United States, American wireless networks are being pushed to the limits--running at 80 percent capacity, compared to an average of 65 percent among our global competitors. Meanwhile, wireless consumers are embracing more powerful devices and doing more with them--especially in terms of data use. A majority of Americans are now data-heavy smartphone users and one in three now also own tablets or e-readers. And we still are in the early phases of the American mobile future.

Given the mass adoption of wireless technologies, analysts and industry professionals have forecasted significant future growth in US mobile data.

Federal Communications Commission "Mobile Broadband: The Benefits of Additional Spectrum" October 2010

To meet exploding demand for mobile data, President Obama wisely has ordered that significant amounts of under-utilized government spectrum be rapidly freed-up so it can be put to more productive use by America's mobile broadband consumers. Meanwhile, the wireless sector is working overtime to develop and invest in more efficient technologies to squeeze as much capacity as possible out of every swath of available mobile spectrum.

With the FCC predicting that currently available mobile spectrum will be maxed out in 2013, there's been increasing talk in Washington about how spectrum-sharing technologies could be a "silver bullet" to avert the looming mobile capacity crunch.

Some sharing technologies in the pipeline do show promise.  But a recent Mobile Future report, Spectrum Sharing: The Promise and the Reality, by engineer Peter Rysavy, reminds us that spectrum sharing technologies, while an important part of longer term solution sets, are not in themselves going to be able, in the short term, to keep pace with the fast-rising, consumer connectivity demands today. 

Spectrum sharing is extremely complex, both from a technology standpoint and one of negotiating among the various parties. Like early versions of spectrum sharing such as the 802.11 standard for Wi-Fi, new technologies and protocols for spectrum sharing will take years to reach adequate scale.

In the paper, Rysavy explains the types of sharing that show promise. These include geographic exclusion zones, which allow certain spectrum to be used in specific areas where it is not needed for other purposes. Rysavy also notes some spectrum sharing systems in use today, such as TV white spaces, are simpler sharing regimes that have taken years to implement.

The technical complexity of spectrum sharing stems from the inherent difficulty of coordinating transmissions of different systems and the difficulty in accurately sensing radio environments. Further complicating the development of efficient and effective spectrum sharing models is the need for certification, standardization, and enforcement, as well as constraints on the evolution of technology. 

The figure below depicts the architectural challenges of an approach that employs some form of spectrum coordination.

Rysavy Research "Spectrum Sharing: The Promise and the RealityJuly 2012

Rysavy recommends that government and industry stakeholders move forward to work through many of the issues around some short-term approaches to spectrum sharing, such as geographic- and time-based sharing protocols. But he is also quick to note that unlocking more sizable opportunities to share among competing wireless service providers and multiple government systems will be complex and time-consuming work.


Spectrum sharing technologies, while promising over the long haul, are no immediate panacea for a mobile industry on the verge of maxing out the wireless spectrum available today.

What does this mean for connected consumers who prefer not to spend more quality time with the universally reviled loading symbol?

Washington needs to swing into action, and the priority must continue to be clearing and reallocating more spectrum for America's wireless consumers. In parallel, policymakers must also encourage and facilitate collaboration between government and industry to pursue spectrum-sharing as part of a broader, longer-term, capacity solution that ensures American wireless consumers and innovators continue to have access to state-of-the-art networks capable of keeping pace with their demands.

While these solutions progress, one thing is clear today: The U.S. needs substantially more spectrum to expand wireless capabilities now.

Ericsson finds that the projected compound annual growth rate of mobile data traffic is about 60 percent, and a key driver is bandwidth-intensive video content.

Cisco predicts that in 2016, 1.2 million minutes of video will cross the network every second, and the U.S. will generate the highest data traffic in the world.

The mobile community is doing all it can to address spectrum constraints. Over the past 10 years, wireless companies have invested more than $23 billion annually in U.S. mobile infrastructure--that is by far more capital investment in America's future infrastructure than any other sector in the U.S. economy. Verizon recently stated that it uses half its capital budget on spectrum efficiency. And the transition to 4G LTE network technology, which is 30-40 percent more spectrally efficient than 3G, is underway by eight U.S. carriers.

Spectrum sharing efforts undoubtedly can help over the long-run, and pursuing this progress is one essential course of action. But in the here and now, the focus must remain on the allocation of more spectrum to help bridge the immediate gap and help maintain the high-speed mobile services American consumers enjoy and our innovation economy urgently needs.

Silver bullets make for convenient storylines. But they are rare for a reason. What's much more vital for our economy as a whole is a combination of hard work, genuine policy leadership, compromise among competing interests and good-faith collaboration to maintain our nation's global leadership in mobile technology. And the time is now to roll up our sleeves and get to work.

Jonathan Spalter, chairman of Mobile Future (, has been founding CEO of leading technology, media, and research companies, including Public Insight, Snocap and Atmedica Worldwide. He served in the Clinton Administration as a director on the National Security Council.