Research On Wireless Propagation Model In Indoor Scene

Wireless systems are an important part of our daily life.Due to their easy access,flexibility,cost-effectiveness and mobility,they have been integrated into residential,commercial,academic and even industrial environments.In order to accurately predict the radio wave coverage in any environment,it is very important for network providers to understand the characteristics of signal transmission and provide effective and cost-effective wireless local area network(WLAN).In the process of short-range indoor wireless signal propagation,due to the influence of the complexity of indoor environment structure on wireless signal propagation,link budget analysis before deployment becomes very important.Therefore,it is necessary to deeply understand and study the indoor wireless signal propagation model and the propagation situation in different indoor scenes,optimize the measured data to obtain a relatively accurate wireless propagation model,and improve the accuracy of indoor wireless signal propagation prediction.The wireless propagation models are classified according to different principles and application scenarios,and the characteristics and representative models of each model are described.The application characteristics of wireless propagation models in indoor scenes such as free space model,ITU-R P.1238 model,Chan model,multi floor attenuation factor model,Lee model,FDTD(finite difference time domain model),ray tracing model are introduced in detail? According to the advantages and disadvantages of different indoor environment analysis model and optimize the model.Compared with the outdoor environment,the short-distance indoor wireless communication environment has more complex building materials and indoor structure,and the wireless signal transmission is affected by more factors,so the research of indoor communication prediction model is more difficult.In order to increase the prediction accuracy of the model,we select corridors,stairs,walls,human body and other scenes to do CW test in the measured environment.Through the data collection,we analyze the attenuation characteristics of different scenes and optimize the commonly used indoor models.Firstly,the appropriate indoor test environment is selected,the test scheme is made according to the characteristics of the scene,and the model is optimized by recording and analyzing the measured data.In the indoor corridor scene,through the test of corridor laboratory NLOS transmission link,corridor laboratory NLOS transmission link and corridor corridor NLOS link,the path loss of wireless signal propagation in different links is compared,and the attenuation characteristics caused by indoor walls are studied;In the multi wall environment,the signal is tested through multiple walls,and the wall loss factor is added based on Lee model;In the stair scene,the propagation characteristics of line of sight propagation and non line of sight propagation are analyzed.It is found that the path loss received at the stair corner platform will change significantly,and the relationship between signal propagation loss and distance is not simple linear.The propagation model is optimized by adding additional path loss parameters to establish the relationship with the number of floors to increase the prediction accuracy of the model;Human scene,through the test of single person,multi person and unmanned scene in the corridor,the influence of human body on the received signal strength is studied,and the method of calculating human body loss is obtained;By adding incident angle and material influence factors to the multi wall model,the structural blueprint of the measured site is gridded in MATLAB simulation software,and the signal strength of each grid point is calculated based on the optimized model to complete the visual analysis of the measured site.