Research On Physical-layer Key Technology Of Millimeter Wave Communication System

The 5th Generation Mobile Communication Systems(5G)is positioned to address the user demands and business contexts of 2020 and beyond.The increasing need for much higher throughput and higher data rate makes it necessary to leverage the large bandwidth available at high-frequency band.The development of millimeter wave(mmWave)communication provides effective means to solve the lack of low-band frequency resources and has become a vital technology for future wireless communication.Prior work mainly investigates the partial performance instead of the overall mmWave communication system and performance evaluation,which provides few reference basis for the realization of actual communication system.Different from the existing contributions,the research on physical-layer key technology of mmWave communication system is studied,including the design of frame structure,the study of short data packet transmission scheme,synchronization algorithm,channel estimation scheme,and the downlink system performance evaluation.The main contents of this thesis are organized as followed:The hybrid beamforming antenna array architecture and clustered statistical channel model of mmWave communication system are described,.Based on the long term evolution(LTE)scheme and mmWave characteristics,the frame structure,physical channel distribution,resource allocation,and reference signal(RS)pattern are carefully designed,which lays the foundation of mmWave physical-layer key technology research in the following sections.A spreading-based short packet transmission scheme for large-bandwidth orthogonal frequency division multiplexing(OFDM)systems is proposed.The simulation results show that the proposed scheme can achieve much lower peak to average power ratio(PAPR)than the repetition-based OFDM symbol.Further,the transceiving scheme of system information,control information,and user data are designed and some key parameters are optimized for the mmWave frequency band.The synchronization signal generation scheme and synchronization algorithm are studied according to the proposed frame structure.Simulation results demnostrate that the proposed algorithm can provide accurate timing offset and frequency offset estimation.The RS generation and resource allocation scheme are proposed according to the frame structure.Further,Two chanel estimation techniques are studied: the RS-based channel estimation including least square chennel estimation,time domain averaging,and frequency domain interpolation as well as data-aided channel estimation.According to simulation results,the RS-based channel estimation technique is adopted in the mmWave communication performance evaluation for lower complexity and favourable performance,while data-aided channel estimation technique can improve channel state information through iteration and feedback operation in few available RS scenario.Based on the studied physical-layer key technology,the simulation parameters and channel parameters are described in detail.Numerical results show that the proposed mmWave communication system can achieve10 Gbps peak rate in 1 Ghz bandwidth.Simulation results of system information,control information,and user data in ideal and non-ideal conditions prove that mmWave communication is a promising approach to handle the lack of frequency resources and provide some reference basis for the realization of actual communication system.