Commentary: What's Behind White-Space Policy?

Telecom Policy Report, Dec 11, 2007

By Hugh Carter Donahue, Ph.D.

In the transition to digital television, the Federal Communications Commission now is determining the rules and regulations for the swath of spectrum, known commonly as white space, in the 54 MHz-72 MHz, 76 MHz-88 MHz, 174 MHz-216 MHz and 470 MHz-806 MHz VHF and UHF bands.

In October 2006, in its First Report and Order, the commission determined it would permit low-power devices in those frequencies as long as their transmissions do not interfere with other, permitted uses at times and locations when and where the spectrum remains unused for television or "other incumbent licensed [and authorized] services."

The FCC articulated the factors it will consider making white-space rules and regulations. First, the FCC will determine whether devices will be licensed, unlicensed or regulated by "hybrid" rules. Second, extensive testing and field testing will evaluate interference. Third, the types and ranges of devices permitted to access the white-space spectrum -- that is, portable, personal and fixed devices -- will be specified. Fourth, spectrum-sensing technologies, employing dynamic frequency selection (DFS), likely will be used in the devices to define uses to vacant channels. The commission's Office of Engineering and Technology (OET) now is conducting device and field tests to determine technical specifications.

Once the FCC sets rules and regulations, firms can begin marketing services in February 2009, when the DTV transition should be complete.

As commissioners ponder policy and OET staff evaluate devices, there are three guidelines worth consideration when articulating white-space policy and technical specifications:

>>Unlicensed uses trump licensing.

>>Spectrum sensing promotes greater innovation.

>>Simultaneous, unambiguous authorization of personal and portable as well as fixed devices will speed investment and adoption

What Will Guide Policy?

Several factors will guide these policies. White-space spectrum has robust propagation qualities, which will yield more innovation more quickly and more extensively in an unlicensed rather than a licensed regime.

For instance, one need look no further than mesh and ad hoc networks, which would flourish in white spaces, to see the benefits of unlicensed development and uses. Mesh networks enable communication outside the wireline telephone and cable plants at less cost than wireless technologies. Each unit in the mesh cooperates to route around congestion due to intelligence in devices, enabling transmissions to course a number of routes. Unlike the phone and high- speed cable Internet, each additional user in a mesh network boosts, rather than drains, functionality by adding signal strength and increasing bandwidth.

The grace of mesh networks resides in keeping so much of the traffic and storage local while at the same time tapping into the Internet through nearby nodes.

Mesh networks will be able to support the synchronization and transcoding of cellphones, lap tops, personal computers and other devices across separate, distinct transmission formats like Wireless Fidelity (Wi-Fi), code division multiplexing (CDMA) and global mobile (GSM). Other mesh-network characteristics include lower energy demands, rapid deployment and configuration, frequency reuse, no lines of sight impairments, redundancy and distributed infrastructure.

Ad hoc networks are comprised of multiple mobile devices capable of routing information to one another. Because locations often change, network topology dynamically adjusts to carriage demands. At this point in time, ad hoc networks are primarily used by the military and by emergency workers. However, as more people use wireless phones, commercialization is nearer.

Spectrum sensing, in turn, enables more innovation for unlicensed uses because spectrum sensing supports flexibility, mobility and greater varieties of solutions than control signal or geographic location and database technical approaches.

Simultaneous authorization of personal and portable devices as well as fixed devices enables competition and promotes consumer welfare through speedier innovation and competitive pricing across more communications platforms.

What Happens Next?

These policy goals and technical specifications -- which Google, Microsoft, Dell, Hewlett-Packard, Philips Electronics North America and Intel are promoting -- admittedly inure to their advantage by permitting technologies that enable these firms to offer complements and substitutes to network providers. The matter at hand for the FCC is to determine whether the policy solutions also inure to the public interest.

Here, several factors indicate these policies (unlicensed uses, spectrum sensing and simultaneous, unambiguous authorization of personal and portable as well as fixed devices) do, in fact, promote the public interest.

First and most important, the DTV transition represents:

>>A technological transition from analog to digital broadcasting and

>>A regime change from administrative agency management of licensees broadcasting in the public interest to private management and ownership of spectrum, long regarded as a public resource, deployed in new ways to promote capital accumulation.