Research And Realization Of Physical Downlink Control Channel In 5G System

The fifth generation(5G)mobile communication system,as the 5th-generation mobile communication technology,has changed the traditional mobile communication technology,promoted the universalization of smart terminals,and also accelerated the development of Internet-related technologies.The accurate transmission and reception of uplink and downlink information in the 5G physical layer provides basic guarantee for the normal communication of 5G,especially the physical downlink control channel(PDCCH)used to carry downlink control information(DCI).This thesis focuses on the research and development requirements of the National Science and Technology Major Project "Enhancing the R & D of Mobile Broadband 5G Terminal Simulators".The physical downlink control channel of the 5G system is mainly researched and implemented.The main research contents and innovations of this thesis are as follows:1.Investigate the process of sending signals on the physical downlink control channel.Combining the characteristics of the 5G PDCCH time-frequency resource structure and search space,a 5G PDCCH resource allocation algorithm based on the reward and punishment mechanism is proposed for the allocation of control resources.This algorithm generates a user priority list based on the reward and punishment mechanism,and optimizes the allocation of the Radio Network Tempory Identity(RNTI).Simulation results show that the algorithm ensures a certain control channel elements(CCE)resource utilization,compared with the RNTI allocation pre-scheduling algorithm,the UE blocking probability is reduced by 57%,and the UE allocation delay is reduced by 30%.Therefore,the control resource allocation efficiency of the proposed algorithm is effectively improved in the PDCCH transmission simulation link.2.Investigate the receiving process of the physical downlink control channel.Based on the characteristics of 5G PDCCH search space,this thesis proposes a PDCCH adaptive blind detection algorithm based on power measurement.This algorithm adaptively determines the order of blind detection aggregation levels based on channel quality,and then uses the power value obtained by power measurement to prioritize and remove candidates of PDCCH at each aggregation level.Compared with the traditional power detection algorithm,the simulation results show that the improved algorithm can reduce the number of blind detections by an average of 5 times while ensuring that the computational complexity of the power measurement part is not increased.In addition,the improved algorithm has more stable performance when the channel conditions are poor.Therefore,the efficiency of blind detection is generally improved.3.According to the research and analysis of the processing link between the sending end and the receiving end of the physical downlink control channel,combining with the blind detection algorithm proposed in this thesis,the PDCCH channel is designed and implemented on the digital signal processor(DSP)and the performance of the PDCCH blind detection process was analyzed.The results show that the number of running cycles of the improved algorithm is reduced by 169805 times than the power detection algorithm.Therefore,the feasibility of the design scheme in this paper is verified.