The dynamic and uneven wireless network traffic load at different time instants and geographical locations has led to substantial underutilization of some spectrum bands while severely crowding others. This project investigates a number of fundamental and challenging technical issues that arise from broadband spectrum trading for achieving superior technical, economic, and social values of spectrum use. The project is an interdisciplinary research effort across mathematics and wireless network technologies. With respect to wireless technologies, this research project outcomes can significantly improve spectrum efficiency and user experience, while benefiting many real-life needs, such as public safety, telemedicine, and social services. On mathematics, the research effort will lead to the formulation of more interesting problems with real world applications and the discovery of new tools for solving such problems.
As a comprehensive investigation to overcome technical challenges that arise from broadband spectrum trading, the project tasks focus on three inter-related key research directions: 1) new graph theory problems, 2) new graph-based resource allocation and utility optimization, and 3) physical layer techniques and utility design. Specifically, the project considers new problems on judicious partitions of graphs and new problems on optimal disjoint paths in weighted graphs using minimum-edge-weight path utility. New solutions and tools developed for such problems can then be applied and generalized for solving various resource allocation and utility optimization problems in broadband spectrum trading. Furthermore, the project addresses new fundamental physical layer issues that arise from spectrum trading. These implementation issues include broadband channel estimation, dynamic pilot placement, interference limited pilot power control, and low complexity broadband spectrum sensing. To establish utility functional curves and to develop means for modeling parametric effects in fine-granularity for more effective broadband spectrum trading, the project applies group-theory-based methodologies to design and carry out detailed tests and analysis in order to fine-tune effective utility functions that incorporate user experience and satisfaction. The research results are also expected to lead to strong social impacts and to provide better technical insights and effective guidelines on governmental regulatory policymaking and technological development regarding broadband spectrum trading for wireless communications.