Collaborative Research: Multi-Input Multi-Output (MIMO) Aware Cooperative Dynamic Spectrum Access

The objective of this project is to develop a Multi-Input Multi-Output (MIMO) aware cooperative Dynamic Spectrum Access framework, termed McDysa, which enables multiple primary users and multiple secondary users to cooperate in dynamic spectrum sharing. By exploiting the underlying cognitive radio and MIMO techniques, McDysa is expected to achieve significant gains on spectrum efficiency while providing substantial enhancements to physical layer security as well. The technical merit and impact of this project are both fundamental and applied, including new problems, algorithms, and methodologies. The McDysa architecture considers multiple simultaneous primary- and secondary-user transmissions by exploiting MIMO techniques. A number of problems studied in the project may foster the development of novel techniques and methodologies toward MIMO-aware dynamic spectrum access. Examples include the novel problem of MIMO-enabled relay selection, insightful analysis of McDysa transmission capacity, and the consideration of secrecy capacity enhancement via friendly jamming. As many of the methodologies in McDysa leverage knowledge from other domains such as game theory, the research outcomes of this project may also motivate advancements of the corresponding domain-specific research. The broader impact of this project also extends to education. The project contains a detailed plan for disseminating the research results and for outreaching to students from underrepresented groups via various channels established in the past years. It also includes a plan for integrating undergraduate and graduate education with research through curriculum development and student involvement. Specifically, the testbed validation of McDysa can offer undergraduate and graduate students valuable hands-on experience, and is therefore an excellent educational vehicle to broaden the participation of students, especially those from underrepresented groups, in computer science research.

Technically, this project defines novel problems and develops new performance-optimization techniques in the following three thrusts that are critical to MIMO-aware cooperative dynamic spectrum access: (i) Relay selection and resource sharing, which focuses on developing novel centralized and distributed relay selection and resource management algorithms based on game theory to enable multiple MIMO-empowered primary and secondary users to cooperate for joint optimization. (ii) Achievable transmission capacity analysis, which investigates the achievable transmission capacity of secondary networks and secrecy capacity of the primary network, and the usage of beamforming optimization to maximize such capacities. (iii) Secrecy capacity enhancement, which studies the usage of two friendly jamming mechanisms, cooperative jamming and artificial interference, in the design of novel beamforming techniques and interference signals for nulling the interference at the receivers, in order to enhance the secrecy capacity of the primary network. Besides the three thrusts, this project also includes the design and validation of a testbed that supports a number of experimental tasks for validating the effectiveness of approaches and methodologies developed in the project. This project also has strong societal impact as the rigorously proven solutions developed in the project can serve as guidelines and backbone for promoting and establishing more flexible spectrum access policies and regulations.