Using cognitive radio to deliver ‘Green’ communications

This paper discusses different ways of delivering dasiagreenpsila cognitive radio based systems. Fundamental is the need to exploit the free spectrum available and power efficient modulation where possible. The paper describes a variable power/bandwidth efficient modulation strategy where the modulation level is adjusted by cognitively determining the assignment and use of the available spectrum, taking into account the channel occupancy probability. Battery life for different techniques is also considered. Secondly, the paper discusses ways to reduce the complexity overall of cognitive radio systems, particularly in the need for spectrum sensing by exploiting distributed artificial intelligence. Techniques presented show how it is possible to largely eliminate the need for spectrum sensing, along with the associated energy consumption, by using reinforcement learning to develop a preferred channel set in each device. Finally, the paper discusses the potential benefits of the use of antenna directionality to improve energy efficiency, and the associated problems that still must be solved before this technique can deliver dasiagreenpsila radio.