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From the perspective of interoperability, Cognitive Radio (CR) is widely studied as an emerging alternative for public safety communications. Spectrum sensing is one of key functionalities enabling the opportunistic spectrum utilization for CR systems. The energy-based cooperative spectrum sensing is mostly adopted in current CR prototype systems due to the low complexity and high detection speed. The cooperative spectrum sensing performance is influenced by the number of collaborative CRs. However, the number of CRs is dynamically changing due to the dynamic behavior of public safety personnel. We study the dynamic behavior of CRs and also derive the exact analytical closed-form expressions for the sensing performance. These expressions lay the framework for utilizing the optimization tools to efficiently guarantee the global optimality for the system parameter design.

Cognitive Radio Networks (CRN), as a promising technology to increase the underutilized fixed allocated spectrum usage, encounters many new practical challenges. Spectrum sensing is one of the key functionalities in CRN. Spatially distributed cooperative spectrum sensing can effectively solve the hidden primary user problem. However, the number of CRs in the cooperation is dynamically changing over time. We study the impact of this dynamic on the spatially distributed cooperative spectrum sensing performance. The dynamic performances are analyzed. The CRN fusion center does lose its sensing performance significantly if the CRN system size is limited too aggressively due to the dynamic spectrum management concerns. Hence, CRN not only is required to dynamically adapt to its surrounding environment but also has to adapt the corresponding sensing parameters due to the dynamic size aspect of the system. The closed-form performance expressions obtained in this paper provide the analytically tractable framework for efficient system design optimization.

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