Research On Spectrum Sharing Technology Of Intelligent Multi-cognitive Users

In order to realize the "Internet of Thing",5G requires wireless communication networks with higher capacity,higher speed and lower latency.On the other hand,the full commercial use of 5G has caused hundreds of millions of terminals to access the network,and consequently,there are problems such as lack of spectrum resources and rising energy demand.The investigation found that the root cause of the shortage of spectrum resources is the low spectrum utilization rate caused by the fixed spectrum allocation strategy.Therefore,how to improve the spectrum utilization and energy utilization efficiency and make the multi-user network more intelligent and efficient to achieve spectrum sharing is a problem that needs to be solved urgently.To improve spectrum utilization and energy utilization efficiency,this thesis conducts related research on Cognitive Radio(CR)and Simultaneous Wireless Information and Power Transfer(SWIPT).The research content is as follows:1.In the 5G network,a system model based on the priority of multi-cognitive users is established.Aiming at the two major technologies V2X(vehicle to everything)and D2D(Device to Device Communication)in the 5G environment,and combining mobile user data services,a communication system model is established based on the three major application scenarios of 5G.Then three different users are given priority to select the spectrum,and the selection of the spectrum is based on the 5G spectrum division rules.According to the advantages of the reinforcement learning algorithm,each user uses the DQN(Deep Q Network)algorithm in the reinforcement learning to interact with the environment in an unknown spectrum environment,and independently learn the selection strategy of the best spectrum.The simulation results show that the algorithm under this model can converge quickly and improve the efficiency of spectrum resource utilization.2.Established a Cognitive SWIPT system model and conducted signal analysis.This thesis combines CR and SWIPT to establish a system model of Cognitive SWIPT network,and then analyzes the signals of each stage and obtains the SNR and the system ergodic capacity’s formula.3.Propose the concept of trust value and relay selection policies.Based on the differences in the communication performance of different cognitive relays,this thesis proposes the concept of trust value to establish the selection criteria for screening high-quality relays.In addition,a variety of relay selection policies and their practical application significance are also given.Simulation shows that Cognitive SWIPT technology can increase the ergodic capacity of the system,thereby improving energy utilization efficiency.