The Research On Dynamic Spectrum Access Technology For Cognitive Radio Based Radio

At present,the use of radio spectrum is still in the stage of pre-planning and static use.This model has poor adaptability to complex and variable electromagnetic environments and serious waste of spectrum resources,which is one of the problems that restrict the improvement of communication support capabilities.The flexibility and scientific issues of radio spectrum usage decisions need to be addressed in order to improve the intelligence level of communication security.With the rapid development and maturity of cognitive radio technology,electromagnetic environment sensing and dynamic spectrum access based on cognitive radio technology is considered to be an important way to improve the radio communication capability in complex electromagnetic environment.An adaptive radio with dynamic spectrum access capability enables a wide-band,fast-sensing electromagnetic environment,discovers spectrum opportunities in complex electromagnetic environments,and automatically builds chains quickly,providing natural anti-jamming advantages.This paper mainly studies the problem of dynamic spectrum access technology based on cognitive radio.Firstly,the basic concept and model of the cognitive radio have been introduced,then the main development process of cognitive radio and the recently researches are presented.Then,we make a statement in details o n the key technologies about the cognitive radio networks,mainly from the spectrum sensing and the dynamic spectrum access.The main work of this paper is on the multiple channels sequential sensing and access technology.Secondly,to solve the delay sensitive multiple channels sequential sensing and access problem,we studies how to find the enough idle spectrum opportunities in the multiple channels cognitive radio networks.We first propose a dynamic programming based sensing delay minimum multiple channels sequential sensing and access algorithm,by jointly considering the channel idle probability,capacity,sensing time consuming and so on.Then we propose a low compute complexity algorithm and analysis the complexity.At last,we verify the proposed approaches' performances by the simulations.Thirdly,to solve the throughput oriented multiple channels sequential sensing and access problem,we studies how to find the maximized throughput by finding the spectrum opportunities in the multiple channels cognitive radio networks.We first propose the throughput oriented multiple channels sequential sensing and access model,analysis the estimate of the primary users' status,and propose the order factor based throughput maximization multiple channels sequential sensing and access algorithm.We prove that the sensing order according to the proposed order factor would be the optimal order for the throughput maximization.At last,we verify the proposed approaches' performances by comparing with the classical sequential sensing approaches in existing works.Finally,based on the USRP hardware platform,the LabVIEW development environment is used to realize the detection and sensing of broadband spectrum and the data transmission function based on dynamic spectrum access.