Spectrum Sharing in Multihop Cognitive Relay Networks
Dr. Wei Zhang
School of Electrical Engineering & Telecommunications
TheUniversityofNew South Wales
Cognitive radio is a novel and promising communications paradigm to address the spectrum insufficiency problem by employing dynamic spectrum access technologies to utilize the licensed spectrum flexibly and sufficiently. In cognitive radio networks, unlicensed cognitive users can access the radio spectrum together with the licensed primary users (PUs) when the spectrum is not occupied by the PUs (white space) or when the spectrum is partially occupied by low power distant PUs and the incurred interference to the PUs is below a predetermined interference temperature limit (grey space). In this work, we develop a novel “whispering radio” technique by utilizing multihop relay techniques and smart power control to take full advantage of the “grey space” of the licensed spectrum. The proposed “whispering radio” can maximize the spectrum utilization efficiency by allowing cognitive radios to access the licensed band even when the primary user is in operation.