imental chunk of spectrum to allow developers Among the new applications in cellular telephones is to experiment. This promising development must be a Bluetooth-like waveform to introduce single people. exploited. As policy is written for this band, it can be "Flirting radios" may subsequently need to have AI deployed and policy violations may be assessed. technology added to filter out the "undesirable" introductions. Who: Vendors, regulators, service providers, and users Much to the dismay of teenagers and employees ev- are highly interested in CR systems. A great deal erywhere, phone tracking applications are now available. of discussion on exactly what that means has Although these capabilities are used "manually" now, already taken place and continues. Academic learning algorithms can be applied to the interface to researchers using COTS SDR demonstrations and create a new "filtered" report stream. There is serious government-sponsored demonstrations using interest in tracking other sets of people, such as first custom-developed SDRs will reduce CR to practice, responders, delivery people, service people, or doctors. for at least the first systems. Where the technology will progress is difficult to predict. As an example, the following organizations are working with CR: 2.4b.8 Summary and conclusions General Dynamics; Shared Spectrum; Raytheon; Lockheed Martin; Bolt, Beranek, & Newman; Radio evolution has taken the path toward more digital Rockwell Collins; Harris; Virginia Tech; and realizations and more software capabilities. The original Northeastern University (and the list has doubled introduction of software made possible software capable during the preparation of this book). radios that communicate and process signals digitally. In the How: The easiest experiments utilize COTS SDR pursuit of flexibility, software programmable radios, and hardware and execute cognitive applications as the even more flexible SDR, have become the standard in demonstrations. Custom-developed hardware is the military arena