Cognitive Coexistence of Non-cooperative Heterogeneous Wireless Systems

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Spectrum sharing has been recently seen as a vital ingredient in enhancing the performance of existing wireless systems, satisfying the growing demand for spectrum access, and enabling new applications. For example, cellular systems can provide improved coverage and capacity via femto cells, in which the spectrum used by the main network is shared over a local area covered by a low power base station. Furthermore, spectrum sharing is receiving increasing attention as a solution to the paradox of spectrum scarcity amid the existence of broad expanses of inefficiently utilized licensed spectrum. In such scenarios, coexistence problems arise between the primary and secondary users of the spectrum, as well as between multiple collocated secondary systems. Usually, the medium access control and physical layer standards do not support inter-network communications, and cooperative sharing strategies are very limited. Hence, heterogeneous wireless systems will need to coexist while operating independently without cooperation. The aim of this research program is to develop an integrated physical, link, medium access control, and network layer approach for the coexistence of non-cooperative heterogeneous systems. This will incorporate real-time multi-dimensional spectrum awareness information (number and type of transmitters, their parameters, location, and traffic characteristics) into the design of the communications protocols. The anticipated research results will strongly impact the evolution of the future radio frequency environment in which increasingly diverse populations of wireless and cognitive radio-based systems will coexist in the same bands. An efficient utilization of the spectrum will thus be enabled, which will open opportunities for new stakeholders, and provide effective alternatives for the wireless industry and consumers to cope with the continuously growing demand for data traffic and services.