Dynamic spectrum access has been a subject of extensive study in recent years. The increasing volume of literature calls for a deeper understanding of the characteristics of current spectrum utilization. In this talk, I will first present some results we obtained from a detailed spectrum measurement study, with data collected in the 20MHz to 3GHz spectrum band and at four locations concurrently in Guangdong province of China. We examine the first and second order statistics of the collected data, including channel occupancy/vacancy statistics, channel utilization within each individual wireless service, and the temporal, spectral, and spatial correlation of these measures. I will then further discuss a stochastic differential equation based wireless spectrum utilization model that we proposed which can accurately captures the dynamic changes in the channel condition induced by the primary usersΓÇÖ activities. Interesting, our large-scale spectrum occupancy measurement study reveals significantly unbalanced usage of spectrum bands owned by different wireless service providers (WSPs) in several representative locations in China. Such imbalance motivates us to consider the cooperation among WSPs to share their spectrum resources. With spectrum-based cooperation in mind, we propose a new wireless market paradigm, where the future wireless service provision will probably be associated with cooperation, in the form of spectrum resource exchange: while each WSP has its own deployed infrastructure (including multiple base stations) and operating spectrum, they can cooperate with each other to share their spectrum in form of time portion. Finally, I would like to conclude my talk with some other efforts we have been spend related to dynamic spectrum management.

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