Economic Viability of Private Commons: Framework and Guidelines for Profitability

Ongoing regulatory reforms have led to several novel spectrum sharing models under the general umbrella of dynamic spectrum sharing. The private commons model introduced by FCC in 2004 allows spectrum licensees to provide secondary access to spectrum on an opportunistic basis while retaining ownership. Since wireless communication systems are typically overprovisioned in order to deliver service-level guarantees to (primary) users under short-term load variations, this model bears significant potential by facilitating utilization of temporal surplus of capacity through serving secondary users at possibly different service level. A potential barrier to adoption of the private commons model is the uncertainty about secondary price-demand relationship which is difficult to predict in an emerging market: A selected price for secondary access may be profitable for some values of secondary demand but not for others, leading to a profound uncertainty about ultimate benefit of spectrum sharing. This paper aims to eliminate such uncertainty by devising concrete guidelines and methods for profitability. The paper establishes that the price of secondary spectrum access can be chosen to guarantee profitability for any value of secondary demand: It is shown that for both the coordinated and uncoordinated commons regimes a profitable price should exceed a threshold value, which can be calculated. Hence profitability of private commons is insensitive to the relationship between price and demand. The paper also leverages the insensitivity property and provides a technique to further enhance revenue via iterative spectrum offerings.