On spectrum sharing in autonomous and coordinated Dynamic Spectrum Access systems: A case study

As an introduction, different dynamic spectrum access architectural concepts are reviewed and three idealized simplifications described: The autonomous, distributed and centralized architectural model. Based on an information-theoretic n-link interference model the global optimum (GO) and competitive optimum (CO) (selfish) power density assignment is discussed. A detailed case study is conducted for a numerical example with 2 links and 2 spectrum segments, comparing the GO and CO solutions, for a low interference, high interference and unsymmetrical interference deployment. It is shown that for conflicting links, with high symmetrical or unsymmetrical interference, the CO solution may become significantly worse than the GO one. We relate these results to the autonomous, distributed and centralized architectural models, and make suggestions for practical policies, information exchange and how to improve the CO solution in the direction of the GO one.