Research On Dynamic Spectrum Sharing And Using Based On Cognitive Radio

Recently, with the rapid development of communication technology, people need more and more spectrum resource, but the frequency resource is very limited. Research shows that the existing fixed spectrum allocation has very low spectrum utilization. In order to get tradeoff between the allocation and utilization of spectrum, cognitive radio technology becomes a hot research spot. Cognitive radio bases on spectrum detection, and is a dynamic spectrum access technology.In this paper we have mainly discussed the interference of coexist system when cognitive radio is introduced, modeled the interference, and estimated the impact of spectrum detection. The key point of interference model is that, in order to protect the primary system from the second system, we can adjust the parameters of the second system when the two systems can share the same spectrum.The main work can be divided into five parts:1) The principle and evaluation method of co-exist system interference, and the process of system-level simulation which provides basis for the modeling and validation of interference model.2) The basic concept and key technology of cognitive radio, the classification of spectrum detection algorithm and the indicators affecting the detection.3) The spectrum detection model which mainly includes the safe area of the cognitive base station and the users, and the core idea of interference model, i.e.the isolation distance.4) Theoretical derivation of interference model which focuses on the equivalent approximation of accumulated interference when it is based on primary system transmitter and receiver detection.5) System-level simulation for the coexistence of TDD LTE and DTV which gives the evaluation of the system performance of spectrum detection and the working parameters.In this paper we focus on the basic flow of system-level simulation rather than the specific algorithm like power control and so on. In addition, we mainly discuss how to introduce into the cognitive radio technology and how to solve the practical problems. Finally, we give the simulation results to evaluate the indicators.