Wireless Channel Modeling In Earthquake Rubble Environment

China is a country prone to natural disasters,once the disaster(such as earthquake)happens,victims are often tend to be trapped in the rubbles and ruins of collapsed buildings,and the past rescue experience shows that almost 80% of the trapped people carrying mobile phones.Therefore,through the mobile phone to determine the location of trapped persons has become a new kind of detection technology.The performance of wireless communication depends on the propagation environment,so the mobile phone Wi-Fi positioning algorithm requires a new wireless propagation channel model under the debris environment.In this paper,we measured the radio channel under debris environment and researched its model.The first,the measurement area locates in the old town of Beichuan which was badly affected by the “5 ? 12” Wenchuan earthquake,the data of the wireless channel frequency domain measurement was collected using the N9918 A vector network analyzer in a frequency range of 2.4-2.5GHz..The second,MATLAB is obtained to process the field measurement data,to get the channel impulse response and power delay profile.The third,according to the different types of collapsed buildings,we established the large scale path loss model.This model is divided into two parts,the first part is the path loss in free space,the second part is the consumption loss in the ruins.Assuming all kinds of material layer arranged in parallel,and then do the calculation.This paper mainly measured environment where there is one layer of reinforced concrete and results show good agreement with the model results.Small scale parameter of debris channel based on the channel impulse response is got and discussed,including the channel mean excess delay,RMS delay and the number of multipath components.Finally,using the frequency domain model of channel auto regressive model,and the order of the model were analyzed.The results show that when the model order in more than 30,the model results are basically stable.