The characteristics of the spectrum, which are necessary for mobile telecommunication services, may determine the advantage of operators' competition for mobile services. We have a focus on the possibility that there would be the core spectrum within the frequencies. We define the core spectrum of frequencies in terms of 4 criteria (global source/roaming, cost-effectiveness, the experience of utilization and the possibility of use). They are based on the aspects of applicative and economic effectiveness by not technological and but market conditions. We have explored the current core spectrum by using the stepwise selection from these criteria. Our result indicates that the core spectrum may be movable with the development of technology and the flow of time. The results of this paper could be practically used as the reasonable justifications of the policies for not only the competition management but also the alignment about the frequencies for mobile telecommunication.

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