The RF environment in the future will consist of many mobile devices operating across a wide range of applications. Most radio developments assume a static operating environment. The physical layer, MAC layer, and network protocols are optimized for that specific environment. However, this new RF environment consisting of many mobile devices will be very dynamic. Radios will need the capacity to sense and adapt to changing environmental conditions. That characteristic is generally associated with cognitive radio. This paper will provide an introduction to new strategies for designing systems for this new, dynamic environment using cognitive radio technology.