Research On Spectrum Sensing In Cognitive Radio Networks

Wireless spectrum is a kind of rare nature resource, but as the rapid growth of the wireless communication and the increasing demand of wireless business for People, the contradiction between the allocation and the usage of the spectrum becomes more and more serious. While the research shows that the spectrum efficiency of the current license spectrum is very low. Cognitive radio is a kind of technology, which by means of sensing the spectrum and then proceed the dynamic spectrum allocation of resources, its goal is realize reuse and sharing to the resources of spectrum in multi- dimensionalsuch as time, space and frequency etc, and thus improve the spectrum utilization efficiency greatly.Spectrum sensing is one of the prerequisite and basis of realize cognitive radio technology. This paper mainly studies the spectrum sensing technology in cognitive radio, focusing on a single node energy detection method and the data fusion algorithm in collaborative spectrum sensing technology .Firstly this paper introduces the research background and significance, and its studies status at home and abroad of cognitive radio. Then we study the concept, the physical structure, key technology and application of cognitive radio in depth. At the same time, we give a introduction of spectrum sensing technology in detail. During which, we focuse on the principle and performance of a single node energy detection method, this laid the foundation for the study of collaborative spectrum sensing algorithms in this paper.Following, we analysis the data fusion algorithm in collaborative spectrum sensing technology. With respect to the existing weighted cooperative algorithms do not consider the impact of distance path loss to the detection performance, this paper presents the weighted cooperative algorithms based on the signal to noise ratio and distance, set a new weight factor, and also imitate the real scenario of spectrum sensing, generate simulation environment parameters randomly, simulate and analysis the proposed algorithm in a variety of channels based on these parameters, the results prove that the proposed algorithm improves the detection probability greatly.As the features of signal to noise ratio for cognitive radio user impact the accuracy of spectrum detection agrithom, while the traditional hard decision cooperative algorithms do not take into account the impact.This paper presents a new hybrid collaboration decision algorithm, in which cognitive users are classified into three kinds according signal to noise ratio, and take of the corresponding sensing algorithm. Finally, the proposed algorithm are simulated using matlab in a variety of wireless channel environment, simulation results prove the effectiveness and feasibility of proposed algorithms.