Dynamic Spectrum Sharing in Cognitive Radio Networks: a Solution based on Multiagent Systems

In modern day wireless networks, spectrum utilization and allocation are static. Generally, static spectrum allocation is not a feasible solution considering the distributed and dynamic nature of wireless devices, thus some alternatives must be ensured in order to allocate spectrum dynamically and to mitigate the current spectrum scarcity. An effective technology to ensure dynamic spectrum usage is cognitive radio, which seeks the unutilized spectrum holes opportunistically and shares them with the neighboring devices. Using cognitive radio capabilities, the nodes are not restrained to static spectrum utilization, rather they can choose it on demand. However, dynamic spectrum usage raises several challenges, which need to be addressed in detail. These challenges include efficient allocation of spectrum between licensed (or primary) and cognitive radio (or secondary) users in order to maximize spectrum utilization and to avoid device level interferences. To this extend, we develop a novel solution for spectrum allocation using multiagent system cooperation that enables secondary user devices to utilize the amount of available spectrum, dynamically and cooperatively. The key aspect of our design is the deployment of agents on each of the primary and secondary user devices that cooperate in order to have a better use of the spectrum. For cooperation, contract net protocol is used, allowing spectrum to be dynamically allocated by having a series of message exchanges amongst the devices. Simulation results show that our solution achieves up to 80% of the whole utility within the span of few messages, and provides an effective mechanism for dynamic spectrum allocation. KeywordsMultiagent Systems; Cognitive Radio; Dynamic Spectrum Sharing; Contract Net Protocol; Cooperation; Ad hoc Networks.