Research On Methodologies Of Measureing E-Band Millimeter-Wave MIMO Long-Range Channels In Over-Sea Environments

Due to the wide range of oceans,complex and changeable weather and difficult construction,the development of marine communications obviously lags behind terrestrial communications.In order to meet the future demand for large-bandwidth,highcapacity,and long-distance wireless communication on the sea surface,the millimeterwave frequency band and Multiple-Input Multiple-Output（MIMO）technology are used to realize long-distance and large-bandwidth wireless communication in the sea environment.Therefore,this thesis mainly studies the long-distance channel measurement method of E-band millimeter-wave MIMO in the sea environment.Based on this method,it carried out on-site channel measurement activities,and made preliminary conclusions by analyzing the measurement data.The specific research process is as follows:Firstly,this thesis made a simple analysis and prediction of the E-band millimeterwave channel in the sea environment.It analyzed the transmit and receive antenna heights required for the presence of Line of Sight（Lo S）paths in long-distance communication.It performed link budget based on the free-space propagation loss model and the attenuation of electromagnetic waves propagating in the air proposed by ITU.And it determined the lower limit of the transmitted signal power.In the time domain,it estimated the channel measurement period by analyzing the maximum Doppler shift.In the frequency domain,it estimated the maximum delay of the channel by analyzing the farthest possible multipath.In terms of antennas,it compared the deployment methods of four antennas in millimeter wave channel measurement.In terms of meteorological factors,it focused on the analysis of the evaporative duct effect.Then,according to the theoretical analysis of the channel,this thesis designed an Eband millimeter-wave MIMO long-distance channel measurement method suitable for the sea environment.It included the design of frame structure,frame synchronization method,frequency offset compensation method and channel estimation method.Among them,the frame synchronization used the method that the frame synchronization field in the frame structure was related to the local sequence.It can achieve frame positioning under channel conditions with low signal-to-noise ratio or high frequency offset.Frequency offset compensation was to estimate and compensate the frequency offset by means of linear fitting.Channel estimation was to use the orthogonal channel estimation sequence in the frame structure and the sliding correlation method to realize MIMO channel measurement.The correctness and reliability of the method were verified by link simulation.Finally,based on the above channel measurement methods,this thesis carried out a4-day E-band millimeter-wave long-distance channel measurement experiment in the waters near Sanya City,Hainan Province,China.The experiments were conducted between two islands 12.2 km apart.This experiment collected a large amount of measurement data.Combined with meteorological data,it analyzed the measured data,and obtained the preliminary analysis results under the conditions of this experimental configuration.The measurement results shown that no significant multipath is observed in the Eband sea surface channel,only Lo S path is observed.The path loss of vertically polarized E-band millimeter-wave long-distance propagation in the sea environment is significantly smaller than that of horizontal polarization.Path loss is positively correlated with absolute humidity,negatively correlated with atmospheric pressure,and has no significant direct correlation with temperature.The long-distance channel on the sea surface will cause the polarization rotation phenomenon of the E-band millimeter wave in the propagation process.And this phenomenon has a more pronounced effect on horizontally polarized signals than vertically polarized signals.The XPR of horizontally polarized electromagnetic waves is negatively correlated with absolute humidity,positively correlated with atmospheric pressure,and has no obvious direct correlation with temperature.And there is no obvious direct relationship between vertical polarization and meteorological factors.This will provide a certain reference for the design of the E-band millimeter-wave long-distance wireless communication system in the future sea environment.