A Policy-Based Framework for Cognitive Radio Networks

Dynamic spectrum access envision the coexistence of primary and secondary wireless services or systems in the same radio spectrum environment. In cooperative dynamic spectrum access, secondary system actors must cooperate among each other to achieve the goal of higher spectrum utilization without the risk of impacting primary services through wireless interference. The cooperation mechanisms among secondary systems must be designed in such a way to prevent misuse of the radio frequency spectrum either intentionally (e.g., malicious attacks) or unintentionally (e.g., failure of a CR system). In addition the design of the cooperative mechanisms should support various types of CR users with different levels of access and to support dynamic contexts where the policies may change due to various factors. This book chapter proposes and describes a policy management framework to control the usage of radio frequency spectrum and resources by secondary CR systems. The Policy management framework is based on distributed Policy Decision Points (PDP) and Policy Enforcement Points (PEP) which regulate the access to spectrum resources. In addition to ensure the reciprocal trust among the CR nodes involved in the exchange of policy information, a trust negotiation scheme is adopted to support the framework. Finally, the policy management framework is applied to a CR scenario where the CR system must transport high data traffic (e.g., videostreaming).