When is electromagnetic spectrum fungible?

Fungibility is a common assumption for market-based spectrum management. In this paper, we explore the dimensions of practical fungibility of frequency bands from the point of view of the spectrum buyer who intends to use it. The exploration shows that fungibility is a complex, multidimensional concept that cannot casually be assumed. We develop two ideas for quantifying fungibility - (i) of a fungibility space in which the “distance” between two slices of spectrum provides score of fungibility and (ii) a probabilistic score of fungibility.