Marcela M. Gomez

Socio-technical considerations for Spectrum Access System (SAS) design

Spectrum Access Systems (SAS) are emerging as a principal mechanism for managing the sharing of radio spectrum. The design of the SAS depends on the specification of spectrum property rights and the governance system by which those rights are enforced. Current perspectives on SAS design have been too limited, focusing narrowly on the technical components without adequate consideration of socio-technical factors that will impact the likely success of any SAS design. In this paper, we apply the social science literature on the management of common pool resources (CPR) to the design challenge for the SAS. Heretofore, too much of the discussion has focused on an overly simplistic characterization of the spectrum rights design space as a dichotomous choice between licensed v. unlicensed, markets v. government, and exclusive v. open. The CPR framework forces consideration of a wider class of design options, positioning the specifications of spectrum property rights more appropriately along a multi-dimensional continuum of rights bundles. The CPR framework highlights the importance of considering formal and informal, multi-layered institutional and market-based interactions among SAS stakeholders when designing a resource management system. We will explain how this leads one to view the SAS as a polycentric governance system (using the terminology in the CPR literature). By examining the economic and social context of spectrum sharing, we assert that these emerging systems must be sufficiently flexible to adapt to various forms of resource governance, which refers to the process by which rights are distributed among stakeholders, how those rights are enforced, and how the resource is managed. We illustrate how the insights from the CPR literature might be implemented in a prototype SAS architecture.

Dimensions of cooperative spectrum sharing: Rights and enforcement

Sharing of radio spectrum requires a careful and nuanced understanding of the rights of incumbents and spectrum entrants. In addition, the dynamics of stakeholders can be understood by examining how various rights are arranged (and rearranged) among them. Importantly, understanding the rights and their distribution is the predicate to developing rational and useful enforcement approaches. In this paper, we show that spectrum sharing involves a rearrangement of the rights associated with radio spectrum among stakeholders. We show how this rearrangement of rights implies the definition of new bundles of rights, appropriate to each particular sharing scenario. We discover these rights - and their (re)arrangement - by examining several cases of spectrum use. We begin with the rights associated with exclusive use and proceed to consider rights arrangement in commons and different spectrum sharing configurations. Further, in the case of commons, we explicitly examine how governance of commons can affect the rights distribution in spectrum. In each case, the bundles of rights associated with each stakeholder changes. New bundles of rights have consequences, not only on the behavior of spectrum users but also on the enforcement process. Our examination of the bundles of rights shows that each rearrangement results in different approaches to enforcement. We demonstrate this by revisiting enforcement in the cases we examine.

How can polycentric governance of spectrum work

Spectrum policy in the US (and throughout most of the world) consists generally of a set of nationally determined policies that apply uniformly to all localities. However, it is also true that there is considerable variation in the features (e.g., traffic demand or population density), requirements and constraints of spectrum use on a local basis. Global spectrum policies designed to resolve a situation in New York City could well be overly restrictive for communities in rural areas (such as central Wyoming). At the same time, it is necessary to ensure that more permissive policies of central Wyoming would not create problems for NYC (by ensuring, for example, that relocated radios adapt to local policies). Notions of polycentric governance that have been articulated by the late E. Ostrom [16] argue that greater good can be achieved by allowing for local autonomy in resource allocation. Shared access to spectrum is generally mediated through one of several technologies. As shown in [21], approaches mediated by geolocation databases are the most cost effective in todays technology. In the database oriented Spectrum Access System, or SAS, proposed by the FCC, users are granted (renewable) usage rights based on their location for a limited period of time. Because this system grants usage rights on a case-by-case basis, it may also allow for greater local autonomy while still maintaining global coordination. For example, it would be technically feasible for the database to include parameters such as transmit power, protocol, and bandwidth. Thus, they may provide the platform by which polycentric governance might come to spectrum management. In this paper, we explore, through some case examples, what polycentric governance of spectrum might look like and how this could be implemented in a database-driven spectrum management system. In many ways this paper is a complement to [20], which evaluted emerging SAS architectures using Ostroms socioeconomic theory. This paper explores how a SAS-based system could be constructed that is consistent with Ostroms polycentric governance ideas. Our approach is to address spectrum management as an emergent phenomenon rather than a top down system. This paper will describe the key details of this system and present some initial modeling results in comparison with the traditional global model of spectrum regulation. It will also discuss some of the concerns associated with this approach.

Wireless Network Virtualization: Opportunities for Spectrum Sharing in the 3.5 GHz Band

In this paper, we evaluate the opportunities that Wireless Network Virtualization (WNV) can bring for spectrum sharing by focusing on the regulatory framework that has been deployed by the Federal Communications Commission (FCC) for the 3.5 GHz band. We pair this innovative regulatory approach with another novel arrangement, Wireless Network Virtualization, and thus assess the resulting opportunities from the perspectives of regulation, technology and economics. To this end, we have established a comprehensive foundation for further exploration and development of virtualized networks that would provide significant opportunities for enabling and enhancing current sharing arrangements.

Wireless Network Virtualization: Opportunities for Spectrum Sharing in the 3.5GHz Band

In this paper, we evaluate the opportunities that Wireless Network Virtualization (WNV) can bring for spectrum sharing by focusing on the regulatory framework that has been deployed by the Federal Communications Commission (FCC) for the 3.5GHz band. We pair this innovative regulatory approach with another novel arrangement, Wireless Network Virtualization, and thus assess the resulting opportunities from the perspectives of regulation, technology and economics. To this end, we have established a comprehensive foundation for further exploration and development of virtualized networks that would provide significant opportunities for enabling and enhancing current sharing arrangements.