SUMMARYThis paper reviews applications of fuzzy logic to telecommunications and proposes a novel fuzzy combining scheme for cooperative spectrum sensing in cognitive radio systems. A summary of previous applications of fuzzy logic to telecommunications is given outlining also potential applications of fuzzy logic in future cognitive radio systems. In complex and dynamic operational environments, future cognitive radio systems will need sophisticated decision making and environment awareness techniques that are capable of handling multidimensional, conflicting and usually non-predictable decision making problems where optimal solutions can not be necessarily found. The results indicate that fuzzy logic can be used in cooperative spectrum sensing to provide additional flexibility to existing combining methods. key words: cognitive radio, cooperative sensing, efficient spectrum use, fuzzy logic, radio resource management, spectrum sensing
The WiMAX Reference Network Architecture can be used in point-to-point and point-to-multipoint network topologies, and is suitable for providing last-mile, building-to-building, and residential broadband connectivity. Another major application, and the main focus of this study, is the use of fixed WiMAX as backhaul for voice and data services. We evaluate voice over IP (VoIP) performance over a fixed WiMAX testbed and quantify the benefits from employing applicationand network-level aggregation. We examine such aggregation schemes using our fixed WiMAX testbed and report the results for both uplink and downlink. If we use objective mean opinion scores (MOS) as the main gauge of overall performance, application-layer aggregation appears to be the best scheme, allowing our fixed WiMAX testbed to sustain nearly three times more flows in the downlink and over two times more flows in the uplink than when no aggregation is used, at comparable MOS values.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.