Scenario making for assessment of secondary spectrum access

Secondary spectrum access, through which secondary users opportunistically access the underutilized radio spectrum, has emerged as a solution to cope with the perceived spectrum scarcity. The potential of secondary spectrum has therefore attracted industry players and regulators worldwide. To assess the real-life benefits of the secondary spectrum, it is crucial to estimate the amount of spectrum available for secondary use. This estimation requires a well defined set of models and parameters, which are collectively termed a scenario. In this article, we demonstrate the importance of scenario making in the quantitative assessment of secondary spectrum access. We first describe the elements that constitute a comprehensive secondary access scenario: a primary system and spectrum, a secondary system and usage, and the methods and context of spectrum sharing. Then we demonstrate how the assessment results of the spectrum availability differ depending on the scenario elements. We also illustrate the crucial aspects of a scenario in the business analysis, which, together with the technical assessment, is the input for the regulatory decision.