Research On Cooperative Relay Technology In Cognitive Radio Networks

Increasing mobile terminals and the application drive the rapid development of the wireless communication technology and mobile communication industry, but take some challenges to us at the same time. As a non-renewable and scarce resources, the wireless spectrum in the mobile communication is growing exponentially. So, how to manage spectrum effectively, how to allocate the spectrum resources and improve spectrum efficiency are important issues in front of the government, spectrum management organization, and communication operators. As the effective solution to the problem of the new technology, Cognitive radio (CR) technology and cooperative relay transmission technology have been widely concerned.CR is a new technology that allows cognitive users to perceive the environment around them and find the spare spectrum to transmit their messages. Cooperative transmission technology is a new technology, in order to against channel fading, that other users help cognitive users to transmit data in some way by sharing their transmitting antennas, thus, the destination node can get space diversity, and improve the diversity gain. So, Combining them becomes the hot point. In this paper, based on the cooperative relay cognitive network as the research object, the problem researched are as follows:First of all, study a collaboration model in which second users help primary users to transmit data to obtain the opportunity of accessing spectrum. The results showed that the different users’ data can be transmitted on spectrum which is divided into two parts. In this way, it can improve utilization of resources and the system performance in the condition. The third chapter in this paper provide a detailed description and experimental analysis.Secondly, study a cooperative model in which primary user coexist with multiple second users.Based on the model, we put forward the allocation algorithm of spectrum and power. Then, take the simulation of the second user’s transmission rate and the outage probability of primary user under the case of changing the distance between primary user’s two nodes. The forth chapter in this paper provides a detailed description and experimental analysis.