Because radio spectrum is a nite resource, its usage and sharing is regulated by government agencies through policies that manage spectrum allocation. With more portions of the spectrum being licensed for commercial use, the importance of providing an increased level of automation when evaluating such policies becomes crucial for the e ciency and e cacy of spectrum management. This poster showcases the Dynamic Spectrum Access Policy Framework, which acts as a machine-readable policy repository providing policy management features and spectrum access request evaluation. It includes the use of the framework's policy management capabilities to create and modify policies in a novel policy representation using two recommended web standards (OWL and PROV-O), and the request evaluation engine to verify the assignment of permit/deny e ects to spectrum requests.
Usable radio spectrum is becoming crowded7 as an increasing number of
services, both commercial and governmental, rely on wireless communications to
operate. Techniques known as Dynamic Spectrum Access (DSA) [
This poster presents the Dynamic Spectrum Access Policy Framework (DSA
Policy Framework) for supporting the management of machine-readable, radio
spectrum usage policies. This is accomplished via the utilization of a novel
policy representation, based on two World Wide Web Consortium recommendations
for encoding ontologies and provenance on the web (OWL and PROV-O), that
encodes its rules in an ontology. This ontology, combined with background
knowledge from a number of relevant sources, is stored in a Knowledge Graph that
is used by a domain-speci c reasoning implementation that mixes a standard
for representation and querying geospatial linked data (GeoSPARQL [
Rensselaer Polytechnic Institute collaborated with spectrum domain experts from Capraro Technologies Inc. and LGS Labs of CACI International Inc. to select and analyze English, text-based policies from the NTIA Redbook and from various Federal Communications Commission (FCC) documents. The English text was converted into a di erent representation, and many of the terms used in the English text were incorporated into a DSA domain ontology. During this process, a number of requirements were elicited: { To store machine-readable spectrum policies in a modeling that supports common constructs { To allow users to interact with the machine-readable policies, creating, modifying, and specializing them as needed { To provide a policy evaluation endpoint able to receive transmission requests in a common format and assign permit/deny e ects, based on existing policies, while explaining the reasons for the policies' decisions
The DSA Policy Framework serves as a centralized, machine-readable, radio spectrum policy repository, providing policy management features (including creation and customization) for a wide range of radio spectrum domain users. It uses the machine-readable policies as a basis for automatically evaluating radio spectrum access requests.
Built on top of the Whyis Knowledge Graph Framework [
The Policy Builder (Figure 1), a key component of the DSA Policy Framework, allows users to build policies from scratch or to create policies by reusing the rules of existing policies. The Policy Builder leverages the DSA Knowledge Graph to provide user support during policy creation. In the back end, the policy is converted to an OWL representation and stored as a new piece of knowledge in the DSA Knowledge Graph.
The Policy Detail view (Figure 2) provides a display of policy metadata, including name, original text and identi er, and a human-readable version of the policy encoded rules. If the policy speci es locations, those locations will be displayed on a map.
Request Evaluation utilizes policies to automatically process incoming
spectrum requests originating from devices that want to use a part of the spectrum.
The request evaluation engine (Figure 3) follows a four-phase pipeline, with a
set of requests as input and the assigned e ect, a list of obligations, and a list
of reasons for each request as output. First, the engine elicits the geographical
relationships among the requests' coordinates and named locations in the DSA
KG using GeoSPARQL. Following this, the HermiT OWL reasoner [
The results generated include ref- Request evaluation engine erences to any policy that was inttecvhhidoeeelgsveermdeerqoevupsoiterlnvsectesu,etehnrvrtetaeahnlteueitovanatupilnoouednlaviectoriyelolvnyneigin.sni,fngoAeernsmktaonabpotlouiiwnolslinge-- tssequeR oeLPSARGQ rrseaLoneOW ir()eTHm rccedeeneP litvaueaon litvauaonE litxanpeaon ltssueR to reason and assign e ects (permit, deny, permit with obligation) to spec- Fig. 3. Request evaluation pipeline trum requests. 3
The DSA Policy Framework is being used in simulated scenarios, where it supports the research & development of other components of a dynamic spectrum management system. It currently contains approximately 165 high-level policies from the NTIA Redbook (including their sub-policies). The DSA Ontology contains 695 classes and is constantly evolving to address new domain constructs and support more precise request evaluation.
The framework is transitioning to support live, over-the-air eld exercises that involve a diverse set of federal and commercial radios. During these exercises, the Framework supports (1) the creation, deletion, and revision of local policies, (2) the real-time processing of numerous spectrum requests, and (3) the generation of explanations that describe how the spectrum requests were processed. The publicly released assets developed during the course of the project can be accessed at https://github.com/tetherless-world/ dsa-open/. 4
While the policy aspect of dynamic spectrum access has been extensively
researched over the past years, there is a shortage of working implementations in
the literature to operationalize it in a real environment. Ulvers y [
The DSA Policy Framework relies on a novel policy representation approach
that builds on previous work by matching the cross-domain policy expression
semantics of XACML [