DARPA's Next Generation (XG) program goals are to develop enabling technology and system concepts to dynamically redistribute allocated spectrum along with novel waveforms in order to provide dramatic improvements in assured military communications in support of a full range of worldwide deployments (see XG home page at HTTP://www.darpa.mil/ato/programs/xg/).

SRI is sole performer on the XG Policy Control project described below.

More Information: http://xg.csl.sri.com/

• Dr. Grit Denker

• Daniel Elenius
• Sam Owre
• Dr. Natarajan Shankar
• Dr. Carolyn Talcott
• David Wilkins
• David Martin

• Cognitive Radio Policy Language and Policy Engine  (2009)
• A semantic web reasoner for rules, equations and constraints  (2008)
• Policy-based Cognitive Radios  (2007)
• A Policy Engine for Spectrum Sharing  (2007)
• Demonstration of a Policy Engine For Spectrum Sharing  (2007)
• Coral - policy language and reasoning techniques for spectrum policies  (2007)

XG Policy Control

The vision of radically increased spectrum usage through XG-enabled radios requires regulatory bodies and spectrum holders to be convinced that the radios will follow rules and policies. This project will develop an expressive and extensible policy language with executable semantics, for describing policies that meet the needs of a wide variety of spectrum regulation bodies. We will also develop efficient reasoning algorithms to reason about policy compliance during radio operation.

The main innovations of the proposed approach include

• An expressive and extensible policy language with executable semantics, for describing policies that meet the needs of a wide variety of spectrum regulation bodies, and for supporting policy reuse and efficient reasoning via a disciplined use of multiple inheritance class structures and meta-policies.
• A policy conformance algorithm that checks the compliance of candidate transmissions using efficient, state-of-the-art rewriting technology. The design of the algorithm is independent of, yet easy to integrate into, any radio design, to encourage competitive, best-of-breed XG radio development.
• A capability to search for transmission candidates if the radio makes an underspecified, unbound transmission request, using fast decision procedures that yield candidate parameter bindings for satisfiable policies. This can considerably increase the use of existing spectrum opportunities of which a radio is not aware.
• The policy language and the reasoning algorithms will be designed to be robust in the presence of conflicts as well as the absence of complete information.
• Policy authoring concepts for creating and visualizing policies, exploiting the complex inheritance relations to structure a policy set and providing Web-style templates that are easy to use for the domain specialist.