Wireless Channel Measurements And Channel Modeling For Inland River Scenairo

Intelligent shipping is a crucial part in intelligent transportation system,while inland river intelligent shipping is an important branch of the intelligent shipping.The inland river basin often has large area,and there are many large and medium-sized cities in the basin.In order to meet the demands for large-flow data services in future intelligent shipping and ensure the safety of inland waterway shipping,it is essential to build a reliable broadband radio communication system.However,the establishment of this broadband radio communication system is inseparable from accurate understanding and description of the wireless channel characteristics under different inland river scenarios.Compared with the studies of mobile fading channels in land-based environments,little current research focused on channel measurements and modeling for inland river environments.Consequently,the channel measurements and channel modeling in typical inland river scenarios are of great significance for establishment of a reliable maritime broadband radio communication system.Moreover,wireless channel measurement is one of a basic task of wireless communication engineering.Its related technologies are also important to the research on wireless communication technology.Measured data obtained by wireless channel measurements are quite useful to propose channel models and their verifications.Aiming at the demand for building maritime broadband radio communication system,this thesis studies channel measurements and channel modeling in inland river scenarios.Primarily,the thesis explores plans for measurement system design,proposes practical measurement schemes,and conducts measurement campaigns.After that,large-scale path loss model for inland river environment and optimal model selection algorithms are presented based on measurement data.On the other hand,the thesis studies small-scale characteristics of the radio channel in urban inland river scenario due to special geographical environment of the inland river.Finally,the measured data and analysis of experimental results verify the correctness and effectiveness of the models and algorithms.The main research contents and innovations are as follows:(1)Methodologies for channel measurements in typical inland river scenarios are studied and plans for the measurement systems design are proposed.The thesis builds a field strength measurement system and a high-precision wireless channel measurement system.Afterwards,long-distance channel measurements(center frequency 1.4 GHz)which contain two typical urban inland river scenarios and a suburban inland river scenario are performed to support the research on large-scale path loss modeling.On the other hand,high-precision channel measurements(center frequency 5.9 GHz)which include both line of sight case(no obstacle obstructs signal transmission)and non-line of sight case(signal transmission obstructed by other passing vessels)are conducted to support the research on small-scale characteristics of the wireless channel.Channel modeling and related theoretical research in the sequel will be dependent on those measured data collected from aforementioned measurements.(2)Large-scale path loss model for inland river environment and two optimal model selection algorithms are proposed.Since the lack of propagation path loss model for inland river scenarios,inland river model is built based on round earth loss model.Compared with the round earth loss model,the proposed model has three important improvements: adjusting the model structure,adding the calculation of the diffraction loss caused by an obstacle with finite dimensions,and optimizing the model parameters.Moreover,the inland river model has re-examined four effect factors in the round earth loss model due to the similarity between sea surface and river surface.Ultimately,comparison result between the proposed model and measured data indicates that the inland river model is effective.The evaluation outcomes of the model selection algorithms also agree this conclusion.(3)The small-scale characteristics of the radio channel in urban inland river scenario and methods for channel estimation are studied.Some channel models related to small-scale fading properties,power delay profile,delay spread and Doppler spread are presented.Specifically,for the small-scale fading properties,the thesis determines the line of sight condition or the non-line of sight condition to which every measurement period belongs.Statistical models of Ricean K factor and Weibull shape parameter are provided.A distance-dependent Ricean K factor model for the urban inland river environment is proposed based on measurement data.For the power delay profile,Saleh-Valenzuela model is analyzed,and cluster identification is performed in each instantaneous power delay profile.After that,statistical model of the reciprocal of intra-cluster decay time constants as well as the cumulative distribution function of the inter-cluster duration is presented.An inter-cluster decay function for the urban inland river environment is studied.With regard to the delay spread and Doppler spread,on the basis of the measured data in both the line of sight condition and the non-line of sight condition,the root mean square delay spread and the root mean square Doppler spread are estimated firstly.Afterwards,their statistical models are provided.Finally,bimodal Gaussian mixture distribution is employed to model the above two characteristics,respectively.