These two challenges are currently being solved by using two new radio technologies. The first challenge is solved using cognitive radios (CR), while the second challenge is solved using software defined radios (SDR). A software-defined radio is a radio communication system that can tune to any frequency band and receive any modulation across a large frequency spectrum by means of programmable hardware which is controlled by software. While a Cognitive Radio is a radio communication system that can be defined as a radio that senses and is aware of its operational environment and can dynamically adapt itself using the SDR platform to utilize radio resources in time, frequency and space domains in a real time basis, accordingly to maintain connection. So cognitive radio systems are a particular extension of SDR that employs model based reasoning based upon its assessment of the radio environment and other transmission parameters. The use of both Cognitive Radios and SDR are expected to be powerful tools for mitigating and solving general and selective spectrum access thus improving current spectrum utilization and will improve wireless data network performance through increased use! r throughput and system reliability.

In this presentation talk, Dr. Nezami will present both technologies, and then will overview several research challenges in making these technologies reality.