Research And FPGA Implementation Of Millimeter Wave Beam Scanning Technology

Millimeter wave wireless communication technology is one of the important fields of wireless communication technology development in the future.Millimeter wave band has more abundant bandwidth resources and larger channel capacity,which makes more fast and reliable communication possible,so it has great potential for development,so it has been concerned by more and more people.Millimeter wave band has a lot of bandwidth resources,but the disadvantage is that it needs to bear a large path loss,so the millimeter wave transmission distance is short,so the beamforming technology based on multi-antenna array arises at the historic moment.By using beamforming technology at the sender and receiver,a beam in a specific direction can be formed,thus a large transmit / receive gain can be obtained in this direction.The sparse characteristics of millimeter wave channel make both sides of the communication have an optimal communication angle.In order to find the best communication angle,beam scanning is needed.Based on the difference of feedback mechanism,beam scanning is divided into interactive beam scanning technology and non-interactive beam scanning technology.Interactive beam scanning technology interactively refines the beam based on the previous measurement results.Non-interactive beam scanning technology uses a fixed set of beam candidates,and the final result is fed back only after the set of beam candidates is scanned.First,in the interactive beam scanning technology,this paper only considers the theoretical rate of the traditional exhaustive and binary scanning.A communication system model with discrete coded modulation strategy(MCS)and beamwidth resolution constraints is established,and the throughput and optimization strategy of the system are analyzed.An interactive beam scanning algorithm based on backward dynamic programming is proposed..Better performance than traditional exhaustive and binary scan methods is achieved in throughput.Second,in the aspect of non-interactive beam scanning algorithm,this paper focuses on the design of non-interactive beam scanning system.First,aiming at the problem of millimeter wave high frequency offset,it is difficult to identify the detection signal at the receiver.Millimeter wave beam scanning detection signal is designed;second,aiming at the mobility scene,the beam scanning switching period in the beam scanning system is studied.Finally,in order to solve the problem of low accuracy of traditional iterative two-stage beam scanning,an improved two-stage beam scanning scheme is proposed based on the allowed beam scanning time and the number of codebooks in the communication system.Finally,a millimeter wave beam scanning communication system is built using FPGA platform,and the beam switching,optimal beam decision,optimal beam feedback and other modules are realized in the beam scanning system.And a small UDP protocol is implemented on FPGA,so that FPGA and PC can exchange data through the network port.Finally,the actual verification shows that the accuracy of the beam scanning system based on FPGA platform is close to that of the beam exhaustive scanning system,and has good robustness.