Policy Description of Distributed Medium Access in IEEE 802.11(e)

The current framework for radio spectrum regulation and spectrum usage is undergoing fundamental changes. In the face of scarce radio resources on the one hand and underutilized licensed spectrum on the other hand, regulators, industry and the research community are launching initiatives towards a flexible usage of spectrum. Cognitive radios realize the dynamic usage of frequency bands on an opportunistic basis. They identify and use under-utilized spectrum in a coordinated way. Policies that enable a software defined medium access are in the focus of this paper. We discuss a step towards the realization of such cognitive radios at the example of the wellknown Enhanced Distributed Channel Access of IEEE 802.11e. This channel access protocol is here specified in a machine understandable policy language, instead of lengthy textual description. Such a machine-understandable description of the protocol enables cognitive radios to operate in distributed environments according to the 802.11(e) standard.