Applyand Channel Building Of MIMO Technology In Vanet

Vehicle wireless ad-hoc networks (VANET) is a new type of ad-hoc networkused in urban situation. It is designed for predicting the serious accidents andproviding prevention.The vehicles act as the communication nodes in thenetwork.By short range wireless communication technology, the vehicles can sharetheir information quickly. So it can enable the drivers to predict the accidents anddecrease the loss. In addition to security applications, drivers’ driving comfort hasbeen raised through the VANET. People can easily connect with the road basenetwork node and instant access the road information which can help with thejourney. Currently VANET have been valued around the world. The famousautomobile manufacturers like BMW, Volkswagen and other manufacturers andSiemens, Bosch and other electronics manufacturers have been either incombination, or separately to begin their own systems developing on VANET. Andthey have already achieved some results. Around in2004some Chinese universityalso began relevant research on VANET. However, due to lack of current domesticautomobile manufacturers to join, there is no relevant industry standards forreference right now.First, this thesis uses finite harmonic function superposition method (SOC)method as the model of the main algorithm finished model. SOC method is arandom phase with equidistant frequency and harmonic functions finite weightedsuperposition of Gaussian random process simulation method. T-junction in theestablishment of the channel model, the first model calculations based on the actualsituation and the difficulty was streamlined to simplify the calculation of the vectorsignal when the signal has little effect in addition to multiple scattering component,but only consider the first scattering component and secondary scattering component. Because T-junction composed by the two roads, in order to facilitate thediscussion, the discussion model used is2*2MIMO array array, while the ease ofdiscussion without loss of generality. And assume that each road uniformdistribution of scatterers and infinite number of scatterers, and ultimately thereceived signal is generated by one of two roads alone through a scatteringcomponent and two roads are carried out in two scattering The secondary scatteringcomponent of three parts, through the use SOC method, three scattering componentparts illustrated separately, so as to establish a reference model. However, becausein practice, the number of the scattering body can not be infinite, and therefore thereference model is established based on stochastic models and determining thesimulation models. Thus completing the entire model.Second, the model for the calculation of the required parameters and optionsare discussed. In comparing the mean square error method, generalized equal areamethod, Riemann and method parameter calculation method, the method byanalyzing the time domain and frequency domain characteristics, the final choice ismore suitable for VANET environment in which the city was Lai Man and method(RSM) as a parameter is calculated.Third, discuss path loss caused by traffic buildings, vehicles, trees and otherobstacles. Also explore the path loss and its subclasses shadow loss and impact ofits size generation principle factors. Discussed in the comparison of the currentmainstream lonely-rice model, Durkin model Okamura model, Hata model, etc.after loss model. Considering VANET environmental factors in which the citytraffic, and ultimately chose COST231-Hata model as the corresponding path lossmodel.Fourth, to complete the path loss simulation. Different frequency signalsthrough the path loss simulation analysis results within the allowable range, thesignal frequency is smaller, the higher the antenna height, the path loss is smaller conclusions. Since there VANET limits the antenna height, and thus raised byincreasing the roadside communication node measures the path loss decreases.While reducing the communication distance and reduce obstacles channel pathway,increases the signal to another aspect of the antenna height, to reduce the effects ofpath loss.Fifth, determine the channel to complete the model simulation. Taking intoaccount the amount of calculation and the actual effect by using two factors, theinitial setting value, the number of the scattering body M, N is set to25. Throughthe channel model space cross-correlation function, the originator of space-timecorrelation function, closed-ended space-time correlation function, the timeautocorrelation function and other statistical properties of the channel. Channelmodel performance obtained by the number of scatterers, vehicle spacing and otherfactors. And by comparing the reference model and determine the error value modelproved the usefulness of the channel model. And in the paper concludes with aVANET channel modeling of future research directions and priorities...