Research On Spectrum Resource Allocation Reconstruction In Cognitive Radio Wireless Networks

With the rapidly increase in the number of wireless communication users and the emergence of new wireless access technologies,fixedly allocated spectrum resources will become very scarce.The emergence of cognitive radio network technology not only brings dawn to solve the problem of shortage of spectrum resources,but also brings opportunities and challenges to the convergence of wireless networks in the future.Introducing reconstruction technology into cognitive wireless networks,adjusting the parameter and configuration of the equipments to meet the needs of users' communication requirement,realizing the co-existence between multiple networks and improving the utilization of wireless spectrum resources,has become a research focus of cognitive network.This paper focuses on two key issues of the spectrum resource allocation and reconstruction of cognitive wireless networks:power control and channel allocation.The content is mainly reflected in two parts:(1)In the cognitive link,the cognitive wireless network needs to perform the spectrum sensing process to judge the active situation of the primary user.At this time,the primary user emulation will simulate and send primary user's signals during the spectrum sensing period,so that the cognitive user mistakenly assumes that the primary user reoccupies the channel,and even when the cognitive user uses the idle channel for normal communication,the primary user emulation attacks the channel and forms a primary user emulation attack.The simulation of primary users not only affects cognitive user's accessing the idle channel opptunitily,but also may cause cognitive user's failure to obtain appropriate spectrum holes for data transmission,resulting in the paralysis of the entire cognitive network system.The third chapter of this article discusses the coexistence mode of intelligent cognitive user and selfish primary user emulation with power control stategy.Combining with the Proximal Policy Optimization algorithm,the experimental results show that the cognitive user can adjust the transmit power to form a coexistence mode with the primary user emulation,so that the two networks can not only achieve the normal communication conditions required by both parties,but also avoid interfering with another network.(2)In various modern communication environments,various wireless communication standards and novel air interface technologies come out,meanwhile,multiple networks coexist in the same space.In the cognitive system,the situation where multiple cognitive networks and primary user networks coexist will face the problem of spectrum resource allocation.In order to solve such problems,the fourth chapter of this article starts from two different networking methods:centralized and distributed,respectively,and discusses the spectrum resource allocation of multi-cognitive networks.Based on the multi-agent reinforcement learning algorithm,which has been budding in the field of wireless communication,a scheme for channel resource allocation using the Actor-Critic algorithm is proposed.Simulation results show that the multi-agent spectrum resource allocation system can improve the overall throughput of the system under different network requirements,and the resource allocation algorithms corresponding to the two networking methods have their own advantages under different network scales.