MODELING THE EFFICIENCY PROPERTIES OF SPECTRUM MANAGEMENT REGIMES Carol Ting, Steven S. Wildman, Johannes M. Bauer Johannes M. Bauer Quello Center for Telecommunication Management and Law Michigan State University 406 Communication Arts and Sciences, Michigan State University East Lansing, MI 48824-1212, USA Email bauerj@msu.edu Carol Y. F. Ting Quello Center for Telecommunication Management and Law Michigan State University 406 Communication Arts and Sciences, Michigan State University East Lansing, MI 48824-1212, USA Email tingyife@msu.edu Steven S. Wildman Quello Center for Telecommunication Management and Law Michigan State University 406 Communication Arts and Sciences, Michigan State University East Lansing, MI 48824-1212, USA Email swildman@msu.edu JEL code: L960, D230, Q210 Keywords: Spectrum commons, Spectrum property rights This study presents an economic framework for modeling service provider and user decisions in wireless communications. The framework makes it possible to model the defining characteristics of different spectrum management regimes and, for the first time, directly compare the welfare properties of different spectrum management regimes. Using computational methods, we compare key aspects of a commons and a propertybased regime. Both the methodology and the comparative analysis move the present debate over the relative merits of different spectrum management regimes beyond the speculative and purely conceptual comparisons that have characterized this debate to date. Because the framework presented can be used to model a wider range of spectrum governance models than the two examined in this paper, it should prove helpful to policymakers in the search for the most efficient mix of different spectrum governance models. A key challenge in spectrum welfare analysis is the high uncertainty over the development of technologies that might permit less disruptive co-existence of users of the same or neighboring spectrum. Among others, work is underway to develop devices with a higher interference tolerance as well as devices with improved capability to recognize and adjust to their radio environment. The outcome of these technological searches directly affects the interdependence of spectrum users and market demand. Furthermore, the development of technologies is intertwined with the choice of governing-regime and, in turn, has implications for the most efficient governance regime. Our models tackle these issues by integrating several features: (1) engineering insights on how receiver design affects the externality imposed by one user on another in a model of demand for wireless services; (2) demand-driven incentives and profit-maximizing strategies for device manufacturers (assuming Cournot behavior) under spectrumgoverning regimes of interest; and (3) a computer program that computes equilibria and welfare performance for each regime. We present and compare results for two very different spectrum-governance regimes. In our first model setting, which belongs to the class of common property regimes (commons), firms have free access to spectrum to serve a specific market segment, and the interference problem is addressed by having a “commons governing body” set a minimum level of interference robustness for devices. In the second model setting, the government establishes property rights for firms seeking to serve a market segment by assigning a fixed and unique band of frequencies within a larger band of fixed size reserved for the service in question. Each firm determines the interference robustness of its devices and the government determines the number of firms allowed to offer service in the band. In both cases, increasing the interference tolerance of a device increases its cost. The results of the first case show that, while mandated minimum robustness levels may improve welfare, the costs of more robust devices overwhelm the benefits of interference reduction fairly quickly in an open access commons regime. The second case gives quite intuitive results: firms adjust the level of interference robustness of their devices to cope with interference from competitors’ devices, and absolutely interference-free protection set by the government may not be necessary for maximizing welfare. The comparative merits of the two regimes vary with market demand parameters and spectrum allocation. References [1] Bauer, J. M., “Spectrum management and the evolution of the mobile services industry,” in R. Cooper and G. Madden (eds.) Frontiers in broadband and mobile communications, Berlin: Springer, 2004 [2]Bauer, J. M., “Impact of license fees on the prices of mobile services,” Telecommunications Policy 27, 417-434, 2003. [3]Maitland, C. F., Bauer, J. M., and Westerveld, R., “The European market for mobile data: evolving value chains and industry structure, Telecommunications Policy 26, 535554, 2002. [4] Ting, C, Bauer, J. M., and Wildman, S. S., “The U.S. Experience with Non-traditional Approaches to Spectrum Management: Tragedies of the Commons and Other Myths Reconsidered.” Paper presented at the 31st Research Conference on Communication, Information and Internet Policy, Arlington, VA, September 19-21, 2003. [5] Ting, C, “Pathways to the Wireless Promised Land: Advances in Wireless Technology and Their Implications for Spectrum Policy.” Upcoming presentation at ICA 2004 Annual Conference, New Orleans, LA, May 27-31, 2004. [6] Wildman, S. S., Electronic Services Networks: A Business and Public Policy Challenge, Praeger, 1991. [7] Wildman, S. S., Rethinking Rights and Regulations: Institutional Responses to New Communications Technologies, MIT Press, 2003.