Automating Ex-Post Enforcement for Spectrum Sharing: A New Application for Block-Chain Technology

Spectrum sharing policy was introduced to utilize the spectrum properly and to overcome limitations in access to radio spectrum. In a broad sense, amounts to a reformation of rights relationships between the spectrum sharing entities. The stakeholders in the sharing arrangement include the (incumbent) Primary Users (PU) who hold the spectrum license, and the (entrant) Secondary User (s) who may use the spectrum temporarily or with rights that are subordinate to the license holders. A set of strategies and technologies are required to enforce rights in any management system and the timing of the enforcement action (ex-ante and ex-post) plays a significant role in such a management system. Ex-ante enforcement is measures are designed to prevent stakeholder rights from being violated. In most discussions, this focusses on ways of protecting a PU’s signal from harmful interference caused by an SU, while ex post mechanisms deal with addressing the consequences of interference after the fact. Practical enforcement schemes have ex-ante and ex-post enforcement that are coupled.The analysis performed in suggests that this approach is too narrow. The authors note that SUs have usage rights that deserve to be enforced as well, and that the collective action rights associated with spectrum sharing may require enforcement measures beyond interference. Collective action rights include the right to determine who may use spectrum (and when they may use it) and who may determine who is excluded. The emergent spectrum sharing systems use geolocation databases (e.g., TVWS databases and Spectrum Access Systems) to mediate spectrum access, so the enforcement of the collective action rights amounts to requiring transparency of decision making as well as audits of these systems.As we move to more intensive sharing of spectrum, the likelihood of events that are enforceable ex post increases, despite ex ante measures. The Enhancing Access to the Radio Spectrum (EARS) second workshop report recognized this and set the goal of lowering the costs by automating some of the ex-post enforcement steps. This paper will study the enforcement in Spectrum Access Systems (SAS) based spectrum sharing regimes. We focus in particular on the enforcement events that occur in the normal course of spectrum sharing; in doing so, we exclude treatment of “rogue” or “pirate” radios, and of interference due to equipment failures of devices and systems that are not participants in the sharing regime. These excluded events are important to address, but we hold that they require a distinct enforcement methodology that may not be amenable to automation under today’s technology.In our analysis, we consider two architectures for enforcement systems: a third party enforcer and a self-reporting approach. Third party enforcer approach, the enforcer must be trusted by all the entities of the system and must have authority to resolve enforcement violation events.We will examine how these two architecture apply in the enforcement of usage as well as collective action rights. A hypothetical scenario of using the recommended ex-ante enforcement (protection zones) and the involved entities will be used to analyze ex-post enforcement steps and the enforcer role in both architectures. This hypothetical scenario concerns about the behavior of the SUs is significant/of concern if SU-mobile devices transmit near PU-base station or if they are transmitting high power signals within the protection zone. These behaviors will cause harmful interference to the PU signal and data received by the PU will be lost. For the ex-post enforcement, we will follow the graduated response approach that had been suggested in.Examine the types of evidence that might be accessible from SASs in support of the ex post enforcement of usage rights. The role of the enforcer, in the ex-post enforcement, would be to detect, forensic, adjudicate, and control parties’ behaviors. Moreover, self-reporting approach, PU and SU would report their own activities to spectrum sharing enforcement authority (which could be SAS for this architecture) when they violated the spectrum sharing policy. Following the self-reporting approach, the detection and forensic roles will be deducted from the enforcer because parties report their violation act, in addition, reducing the risk of getting uncertain sanctions when violating the spectrum sharing policy. The paper will help the researchers develop feasible approaches to adjudication and will help policymakers the efficient enforcer role on the enforcement system could be. Although, the need to lower the cost of the ex-post enforcement by automating some of the steps, this paper will help on that matter too.