Research And Implementation Of Ultra-high Speed Broad Band Transmission Of Wireless Millimeter-wave Communication

Nowadays,the astonishing growths of businesses in wireless networks require building a new wireless network with higher data rate and lower delay as soon as possible.Due to the limited frequency resources,it is hard to allocate larger communication networks on the existing sub-6 GHz bandwidths.Millimeter-wave(mmWave)systems offer a huge bandwidth resource and favourable features,which make it the key technology of the 5th Generation mobile communications.There are already lots of researches on mmWave communications from companies,vendors and universities.This thesis aims to research on the key technologies of ultra-high-speed mmWave communications,and to complete the hardware implementation of mmWave communication system based on the IEEE 802.11 aj and field programmable gate array(FPGA),which is combined with the novel beam forming technology that can further enhance the system performance.Firstly,the technologies and standards of ultra-high speed mmWave wireless transmission are studied.This thesis attaches more importance to the beam sweeping and tracking technologies in beam forming.When it comes to the standards,some key technologies adopt by IEEE 802.11aj(45 GHz)are studied.Then this thesis studies the physical layer standards of IEEE 802.11aj(45 GHz),i.e.basic characteristics,parameters,physical protocol data unit frame formats and baseband processing flows.After that,the requirements of constructing a mmWave OFDM wireless communication system are analyzed,including the processing flow design,interaction of data,matching of the interface,allocation of the storage and computing resources.Finally,the complete hardware architecture of ultra-high-speed mmWave wireless communication system is designed and elaborated.In order to solve the problems met in implementing the hardware system,this thesis proposes related schemes and gets them realized based on the hardware platform.For instance,a mixed parallel scheme,which suitable to this hardware platform,is proposed to solve the problem resulted from the mismatching between the processing clock frequency in the baseband and the sampling rate in the digital-to-analog/analog-to-digital converters.Moreover,this thesis introduces and designs a novel optical fiber communication mechanism to break the upper limit of the dynamic memory access inner the existing hardware system.The time accuracy of the Host is relative low compared to the ultra-high-speed transmission,which brings disordered time-slots in both the FPGA and the Host.An elaborate queue-based scheme is developed for solving this problem,and the design of a variable-length scrambler is shown as a example.This thesis finally completes the hardware implementation of a entire ultra-high-speed mmWave OFDM wireless communication system,whose procedures are shown by the programs design in the Host and the FPGA.In the FPGA,the generation and reception of the baseband waveform is designed according to the IEEE802.11aj(45 GHz).As for the receiver,the key progresses include time synchronization,fast fourier transform,channel estimation and equalization,phase correction,demodulation,channel decoding and descrambling.The LabVIEW implementation of some key modules are represented.The host has four main functions,i.e.parameters configuration,performance exhibition,data relay and devices control.The hardware verification indicates that this single-input single-output hardware communication system is able to achieve 2 GHz realtime bandwidth and approximate 6 Gbps theoretical data rate.The valid throughput reaches up 3.1 Gbps using 16-QAM modulation.Based on the hardware system,some mmWave beam forming technologies are further studied,including the code book design,beam sweeping,beam tracking and channel state information feedback under single user situation.They are designed and implemented by using the NI mmWave hardware platform and the array antennas of the TMYTEK BBox-Lite.The verification under different scenarios and operating modes indicates that the system can effectively completes the auto alignment of the beams in the transceiver,which can further enhance the system performance compared to the communication systems using traditional antennas.