With the proliferation of wireless applications and devices, most recently the smart phones, the demand for wireless data, equivalently for wireless bandwidth, keeps an exponential growth. Unfortunately, all our wireless vision needs to be realized through the public radio spectrum, which cannot be further created but has to be efficiently shared among various wireless systems and devices. While significant progress has been made in efficient spectrum access and sharing technologies, their successful deployment towards fulfilling the national broadband plan relies crucially on the development of adequate security mechanisms. Such security mechanisms should be able to protect the welfare of all stakeholders in the spectrum sharing systems, in particular the federal government and military users; meanwhile, they should also be able to address the new challenges brought about by the advanced technologies and new access paradigms that have enabled innovative spectrum sharing. At the current stage, an effective security mechanism for spectrum sharing systems is lacking, which significantly impedes their practical deployment and consequently the realization of the anticipated wireless broadband revolution. This proposal constitutes a solid step towards filling this gap, seeking to obtain a deeper understanding of the emerging attacking strategy and behavior in this new arena, and develop a holistic view and solution to the security of spectrum access and sharing. The expected outcome will be valuable to all players in wireless industry, as well as to all sectors of the national economy that benefit from wireless innovation. The inter-disciplinary nature of the proposed research will naturally help promote cross-disciplinary education and well-rounded training of future IT workforce.
The proposed research will be focused on the security aspects of the dynamic spectrum access (DSA) paradigm and cognitive radio (CR) technology, which receive major research interest and also impose foremost research challenges. It is comprised of two thrusts. First, cross-layer attack and defense in CR networks will be addressed. Current research on CR security mainly focuses on attacks and defenses at individual protocol layers, but cross-layer attack naturally fits the CR setting and can lead to unprecedented detrimental effect. In this project, a general class of cross-layer attacks will be investigated. In response to cross-layer attacks, a cross-layer defense framework is subsequently proposed, for which two research tasks will be focused on: advance in individual detection modules for attacks unique to CR functionalities, and metrics-driven cross-layer fusion. In existing studies, the assumed capabilities at CR are rather modest. With the further development of CR technology, wireless devices will grow in reasoning and learning capabilities. Meanwhile, such technology progress can also be exploited by the adversaries to launch more sophisticated malicious attacks. In the second thrust, assuming more intelligence and growing reasoning and learning capabilities for both the CR user and the adversary, the arms race between them will be explored through the stochastic game modeling and multi-agent reinforcement learning (MARL) methodologies. The proposed research will be evaluated through theoretical analysis, numerical and network simulation, prototype implementation, and experimentation on real testbeds.
