Solving the spectrum squeeze (Abridged version)
Connecting state and local government leaders
Future of IT: We need new approaches and new technology to make the most of a finite resource.
FEW TECHNOLOGICAL ADVANCES have transformed the way we live and work in the world more than wireless communications.However, the exponential growth in demands for wireless applications has us headed on a collision course with the reality that electromagnetic spectrum is a finite resource.We've all seen and been part of the explosion of mobile and wireless services in the commercial market. In the past two years, the number of wireless subscribers in the United States alone swelled by 50 million.What's more telling is that the proportion of wireless-only households in the United States has reached nearly 13 percent. That's a huge shift.Globally, a staggering 2.5 billion subscribers were using mobile phones based on the Global System for Mobile Communications standard ' the most commonly deployed digital cellular standard ' as of June. The number of subscribers will reach 3 billion by 2009. Bandwidth demand is not just for voice but for significant increases in data and multimedia applications. The commercial appetite for spectrum has grown so dramatically that when the U.S. government auctioned spectrum for advanced wireless services last year, some 107 licensees paid about $14 billion to secure more than 1,000 licenses.From the military's perspective, there are serious concerns about spectrum requirements for radar, sensors, navigation and several capabilities on which warfighters depend. Spectrum conflicts on the battlefield, especially when coordinating with coalition forces, can have lethal consequences. The military and the government are also using wireless for security systems, intrusion detections, video surveillance, and sensors that detect biohazards and report them back to control centers.The bottom line is the projected requirements for using electromagnetic spectrum are greater than what is feasible today.To further complicate matters, each country has sovereign rights over how spectrum is used within its borders and tends to use its spectrum in different ways.All these factors put tremendous stress on our use of the spectrum ' especially in lower frequency bands, which are better for mobile types of services.Emerging technologies are often seen as the means for extending these limits. There are several types of technologies, developed by industry and other government entities that we at DISA and the Defense Spectrum Organization continue to monitor and explore. (See list.) Perhaps the most promising of these are the smart radio systems that will use dynamic spectrum access solutions, such as software-defined and cognitive radios. These solutions would lead to devices that could recognize where in the world they were. They could also automatically apply policies appropriate at that location ' by consulting a national allocation table that defines what frequencies can and cannot be used within a region or a nation. And they could sense ' and adapt to ' the radio frequency environment, switching to frequencies not being used. Another idea is adaptive antennas that allow devices to better interact with that environment.Developers are working on many of the required pieces today. DARPA, for instance, is doing a lot of work in that area with a program called XG by pulling together a variety of technologies as they mature with the aim of integrating them.Meanwhile, we must do our due diligence and understand how we are going to use any emerging wireless technology to avoid unintended consequences. For example, WiMax would enhance our capabilities from the military standpoint. But it relies on multiple bands to operate, and one of those bands impacts our military radar system. So we must ensure that when we deploy a new technology, we use it in a way that does not degrade our operations.Too often, when we are dealing with spectrum use and management, we've viewed it collectively in terms of a zero-sum proposition.Rather, we need to create a win-win proposition by going back and looking at technologies and techniques that improve efficiencies or might allow coexistence of services.Spectrum is the ultimate team sport. It takes everyone pulling together and trusting one another to be successful.
The Defense Spectrum Organization, reflects how seriously the Defense Information Systems Agency regards the management of spectrum resources. Paige Atkins, DSO's director, provides executive leadership to the Defense Department's center of excellence for electromagnetic spectrum engineering and management.
An expanded version of this article appears on GCN.com/884.
Paige Atkins
An expanded version of this article appears on GCN.com/884.
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