Study Of Short-Range Wireless Channel Testing And Its Propagation Characteristics For Indoor

With the rapid development of wireless communication technology,the products of wireless communication technology emerge in endlessly,such as mobile phone application software,blue-tooth headset,intelligent home and so on.Short range wireless communication technology has become the current hot technology.Therefore,the short distance wireless communication technology represented by Zigbee technology,Bluetooth technology and Wi-Fi technology is being penetrated into all areas of people's daily life,because of its large capacity,low power consumption and high reliability,which is showing great application prospects.Short range radio waves are mainly transmitted through wireless channels,However,during its propagation,because of the existence of obstacles,often occur many transmission situations,such as reflection,refraction and scattering,which result in signal attenuation,delay and so on.Moreover,due to the long transmission distance and complex environment,short distance wireless channel will exhibit randomness and time-varying characteristics,which fully shows the complex and changeable characteristics of short distance wireless channel.Therefore,in order to study the path loss,multipath delay and channel fading effectively in the channel,we need to establish a short distance wireless transmission channel model.Therefore,the establishment of accurate channel model is the main theme of this paper to analyze channel parameters,improve channel capacity and reduce multipath delay.First of all,short range wireless communication technology and its related properties are briefly summarized.The method of parameter calculation expression in multipath channel,time domain and frequency domain test modeling method are given respectively.Then,we focus on the parameter characteristics of the distance wireless channel under the frequency domain.Grid method is used to test the parameters of the wireless channel under the LOS and NLOS scenes.Through basing on the frequency domain model and researching the results of the parameters,a channel test model for 5.8GHz band is established.Secondly,to study the path loss in the indoor environment,establishing a path loss model for multipath channels.On the basis of Finel's law,the expression of reflection coefficient is introduced which takes the distance of the transceiver as a variable,then proposing a "multipath propagation path loss model".By comparing with the present model?free space model and published data by TG3c,the feasibility of the multipath channel path loss model were verified.Finally,studying the spatial fading correlation of MIMO LA and CA,deriving the fading correlation approximation algorithm.and analysising the influence of array spacing,arrival angle of arrival signal and power spectrum expansion on the channel of MIMO antenna system.By studying the channel capacity and operation time of three typical Massive MIMO systems with different antenna numbers,it is shown that the approximate algorithm has better computing efficiency.