Research On Cognitive Radid Spectrum Sharing Technology Based On OFDM

Currently, the radio spectrum resource shortage which limits the application of wireless communications and services is the bottleneck of sustainable development. As a new technology, Cognitive Radio (CR) has changed the traditional use of radio spectrum authorized by the government in the past, considered the efficient spectrum utilization as its target, and allowed non-authorized users transmission by using the spectrum of authorized user, which is the new method to solve the problem of radio spectrum shortage. However, the flexible selecting frequency programs of orthogonal frequency division multiplexing (OFDM) technology provides a good platform for achieving cognitive radio systems.For OFDM-based cognitive radio system, this algorithm through theoretical analysis and simulation, focuses on the design of system framework and research of spectrum sharing model of cognitive radio systems based on OFDM, user resource allocation and other key technology.The thesis stated the optimum power allocation algorithm in the single cognitive radio scene, greedy algorithm, and its improved algorithm. Moreover, based on the single cognitive user allocation algorithm, the multi-user spectrum allocation algorithm which includes multi-user water-pouring and proportional fairness improved algorithm are researched.