Apple iCloud. Google Music. Amazon Cloud Drive. Microsoft SkyDrive and Office 365. OnLive. Dropbox. Jungle Disk. These are just a few of the many new services promising to let consumers access their music, pictures, videos, games, documents and other files anywhere, anytime, from any device via wireless networks. In theory, these services offer a bright future for consumers, especially those who value convenience and want access to all their content no matter where they are.
But in reality, there are dark storm clouds brewing. These mobile “cloud” services won’t happen without radiofrequency spectrum, a natural resource that is quickly becoming scarcer because of outdated regulatory and technological spectrum access methods.
Better policy isn’t enough
Incumbent wireless service providers and a chorus of experts have warned this looming spectrum crisis could threaten the success of cloud-based and other high-bandwidth offerings. Wireless carriers are already bending under the pressure of increased data traffic. Add these new cloud services to the mix, and consumers will be using even more bandwidth as they access their content on the fly.
In Washington, D.C., the focus has been on repurposing spectrum currently being used by television broadcasters and the federal government, including the military and law enforcement agencies. Unless policymakers and current spectrum users immediately chart a new course, this increasing consumer demand will lead to a perfect storm that could sink the hopes for wireless access to the cloud.
A silver lining is on the horizon, however, in the form of policy and technological innovations. While consumers thirst for better, faster and more robust wireless technologies, Congress, together with the Obama administration and the Federal Communications Commission (FCC), are searching for new spectrum to offer at auction. But as President Obama recognized in an executive memorandum last summer, we can “unlock the value of otherwise underutilized spectrum and open new avenues for spectrum users to derive value through the development of advanced, situation-aware spectrum-sharing technologies…”
Several bills recently introduced in Congress would reinvest some of the proceeds from spectrum auctions back into technologies that enable more dynamic access to spectrum resources, thereby creating more possibilities for accelerating rapid and efficient access to additional broadband spectrum.
But at the end of the day, better policy does not eliminate the need for new, widely adopted technologies that enable more efficient spectrum access. Policy can turn the engine on, but technology is where the rubber meets the road.
Too much, too fast – we need better tech
Consumers are replacing their basic clamshell cell phones with smartphones and tablets that enable them to not only check email, surf the web, and yes, still make voice calls, but to download books, stream music, watch movies and play games with other users. Analysts predict that by 2015, shipments will nearly double (from 302.6 to 982 million). IDC also forecasts that worldwide tablet shipments will grow at an even faster rate of 57.4 percent.
The rising smartphone and tablet revolution spurred by Apple’s iPhone and iPad has already resulted in an explosion of data traffic growth. Cisco Systems predicts that Internet traffic will grow at an annual rate of 32 percent from 2010 to 2015, but traffic from wireless devices will exceed traffic from wired devices by 2015, with Wi-Fi and mobile devices accounting for an estimated 54 percent of total traffic.
While the Administration, Congress and the FCC search for more spectrum to auction, wireless service providers are already trying to ensure that their networks don’t come to a crashing halt because of data demands. Some of the top wireless companies are now charging heavy data users higher fees, offloading traffic to Wi-Fi hotspots and acquiring more spectrum through colossal mergers.
The growth in wireless traffic is just too fast, and simply reallocating spectrum is not a long-term solution. We also need to focus on spectrum utilization if we’re going to meaningfully address the issue in the long run.
One path forward – dynamic spectrum access
None of the ongoing efforts to repurpose Federal or television spectrum will adequately address the spectrum supply problems because they do not deal with the artificial scarcity and technical inefficiencies that led to this crisis in the first place. Decades of ineffective management and inefficient use of spectrum resources have depleted the stocks.
The traditional approach has been to allocate frequency bands for exclusive use within a geographically defined area, no matter how intense or infrequently that spectrum might be used. This is comparable to providing every car its own road to the same location, meaning that while almost all of the useable radio spectrum is allocated, it is dramatically underutilized.
Measurements performed by various companies have shown that less than a third of the spectrum is used, even in major markets during peak hours of use. The huge disparity between spectrum use and availability highlights one of the reasons President Obama and several members of Congress are calling for technological solutions to help solve the ever-increasing demand for spectrum.
Dynamic spectrum access (DSA) solutions will help wireless carriers and other users optimize this valuable resource while giving consumers, first responders and soldiers the bandwidth they desire. Developed with funding from the Defense Advanced Research Projects Agency (DARPA), DSA senses when particular frequencies are in use and automatically switches to different channels when necessary to avoid interference. DSA not only is well positioned to overcome the obstacles inherent in the regulators’ traditional spectrum allocation methods, but it will also improve spectrum utilization in multiple dimensions by allowing multiple users to share spectrum.
How DSA works
DSA was developed in 2001, and is a software solution that can be deployed in base stations and radios. Currently DSA is being tested on military radio systems, but the technology offers great potential for use in various wireless networks because of how flexibly it can be deployed.
DSA improves spectrum utilization in three dimensions: frequency, location and time. It enables a network to opportunistically use channels (frequencies) at points in time and space when/where they are not in use. When a primary user appears on the channel in use, the DSA network immediately moves to an unoccupied channel. Because most RF channels are utilized only a small portion of the time and in a fraction of locations, DSA enables two or more networks to share a given band. Among other things, this allows a spectrum licensee to deploy more than one application/service in a given band; a primary and one or more secondary networks to cooperatively share a band; and also permits numerous non-cooperative networks to share a band.
By enabling this type of sharing, DSA can dramatically increase the capacity of a spectrum band – in some cases by as much as 10 times.
The potential of DSA
Because of the potential capacity gains, Congress has expressed great interest in the potential of DSA and other spectrum-sharing technologies. Spectrum bills introduced on Capitol Hill include language promoting the use of advanced spectrum-sharing technologies to encourage more efficient use of the spectrum. Additionally, the FCC has a pending Notice of Inquiry (NOI) on DSA to gather information about the technology and evaluate next steps for possible broader use of DSA.
In response to the FCC’s NOI, several carriers have indicated that they are using aspects of DSA in their LTE networks, to enable better usage of spectrum to which they have exclusive rights. Although wireless carriers are generally opposed to use of DSA technology to enable other users to share the spectrum they control, they do support the use of DSA to open up additional frequency bands for sharing.
DSA’s built-in situational awareness enables access to tens of billions of dollars of spectrum assets without requiring existing users to move out. As a result, DSA will dramatically increase not only the value of repurposed frequencies but the capacity of any given spectrum band, allowing smartphone and tablet users to keep reaching for the cloud.
Tom Stroup is the CEO of Shared Spectrum Company.