With widespread proliferation of wireless communications and intensive use of electromagnetic spectrum, the need for smart radios is far greater today than it was a decade ago. Whether it is a 3G cellular handset or a wireless network terminal, the emerging applications are demanding radio systems that can effectively and efficiently use the RF spectrum. In addition, such radios must also determine location, sense spectrum use by neighboring devices, change frequency, adjust output power, and even alter transmission parameters and characteristics. In essence, service providers and users are all seeking radio technologies that will provide flexible, efficient and comprehensive use of the available spectrum.

While software-defined radio (SDR) can reconfigure a radio's operating parameters, it cannot perceive the environment and learn from its experience. Likewise, there are smarter radios in the market today, but still limited in their understanding of the environment in which they operate. Cognitive radio (CR) technology may be the Holy Grail. According to Allan Margulies, CEO of the SDR Forum, SDR can serve as a key catalyst to the development of cognitive radio. And, the forum has the appropriate resources, talent pool, and commitment in place to provide tightly focused technical analysis and broad cross-disciplinary research on this issue, stated Margulies.

In response to this growing interest in CR in the wireless community, the SDR Forum has developed new initiatives to support the advancement of CR technology. Thus, to leverage the role of SDR in the continued development of CR technology, the forum has created a Cognitive Applications Special Interest Group (CASIG) and a Cognitive Radio Working Group (CRWG). “The cognitive radio concept is commonly referred to as ‘the next step up’ for software-defined radios emerging today,” said Bruce Fette, technical committee chair of the SDR Forum. “It's an up-and-coming technology that promises to deliver a radio that is aware of its RF environment, can adapt to this environment, and consequently can adjust its operating parameters,” said Fette.

With this unique two-pronged approach, the CASIG is studying the business case, market drivers, regulatory, and other cross-disciplinary implications of SDR within a CR framework, while the CRWG group is working to produce technical guidance and standardization to design, develop and implement cognitive concepts and features based on SDR technology and architecture.

Well, software radio is a reality today. While the Department of Defense's (DoE) Joint Tactical Radio Systems (JTRS) program has been in progress since the mid 1990s, numerous coalition forces have similar programs under way worldwide. Simultaneously, in the commercial sector, SDR-enabled base stations are continuing to come to market throughout the world. With public safety/homeland security on the top list of the government, agencies are closely examining ways to leverage software radio capabilities to ensure intelligent and reliable communications within the defense and commercial sectors.

But, CR is a step beyond SDR. Being in the formative stage, the challenges ahead are plenty for CR technology. The first task will be to convert this concept into a concrete definition, so that technologies and software can be identified that can address the problems. The next hurdle will be to identify applications and standards that can best exploit CR's benefits, thereby, ensuring that developers do not get caught in the politics of licensed and unlicensed bands. That means the Federal Communications Commission (FCC) must develop rules and policies that govern the use of spectrum in CR equipment. Incidentally, the FCC has recognized CR's ability to offer such a smart radio. And as a step in that direction it has proposed a rulemaking and request for comments. So must the international agencies governing policies concerning CR systems. It is to be seen how effectively different organizations work together to turn this radio concept into a commercial reality.