A Real-Time Medium Access Protocol Supporting Dynamic Spectrum Allocation in Industrial Networks

Cognitive radio with spectrum sensing and spectrum reuse has great opportunities for industrial networking. Adapting to the current interference situation and utilising the available frequencies in an effective manner can greatly improve the data delivery capabilities. At the same time, real-time demands must be met. In this paper, we present a medium access control protocol supporting dynamic spectrum allocation as done in cognitive radio networks, providing deterministic medium access for heterogeneous traffic. The possibility of spectrum sensing in the nodes opens up for the possibility of increasing successful data transmissions, and a real-time analysis framework with three formalized constraints to be tested provides support for guaranteed timely treatment of hard real-time traffic. The real-time analysis framework includes a new type of delay check that more exactly bounds the delay compared to earlier work. Simulation experiments and performance comparisons are provided.