Research On Visible Light Communication Oriented To Vehicle Networking System

Visible light communication(VLC)is a more advanced communication technology at present.It has become a hot research to apply VLC in the Internet of vehicles to form intelligent transportation system.However,due to the interference of sunlight and other artificial light sources,the optical signal propagated in the outdoor environment will be distorted greatly,and the ping-pong effect will easily occur when users switch the network,which will affect the stability of the network.In order to achieve high-speed and stable visible light communication in the Internet of vehicles,the analysis of strong background light interference and network switching characteristics of visible light communication in the Internet of vehicles is the most important.Therefore,this paper focuses on two aspects of VLC: strong background light interference and network switching.Aiming at the problem of large background light noise in the visible light communication system of the vehicle network,combining the improved EEMD(Ensemble Empirical Mode Decomposition)with CS(Compressed sensing),an improved strong background light noise suppression algorithm based on the VLC system of the vehicle network is proposed,which adaptively selects the IMF component threshold of the EEMD,effectively avoids the selection of complex and tedious threshold,suppresses the noise in the reconstruction process,and achieves the purpose of denoising.Firstly,filter is used to remove the noise of artificial light source;secondly,EEMD algorithm is used to remove the noise,and the improved ant colony algorithm is proposed to determine the threshold value of IMF(Intrinsic Mode Function)component of EEMD to get the reconstructed signal of EEMD;secondly,the compressed sensing algorithm is used to compress and reconstruct the filtered signal to get the reconstructed signal of CS algorithm;finally,two algorithms are used to reduce the noise These reconstructed signals are weighted to get complementary accurate denoising signals.The simulation results show that the algorithm proposed in this paper has a good effect on the suppression of the background light noise of the visible light communication in the vehicle networking system.Aiming at the problem that the evaluation gap between networks is too small and the ping-pong effect is easy to occur when the outdoor vehicle networking visible light communication system is switched,an improved multi-attribute switching algorithm is proposed.Firstly,the input attributes are forward-looking;secondly,the weights of the user’s completely independent objective network selection are obtained by using the improved objective weight solution algorithm to reduce the influence of the dependency between attributes on the network selection;finally,the subjective and objective weights of the network selection are combined according to the one of the subjective and objective evaluation values According to the distribution model,the final weight of each attribute is obtained,and the network evaluation value of each network is obtained by using the weight.According to the ranking of evaluation value,the network with the largest evaluation value is selected as the target network.Simulation results show that the proposed algorithm can find the best target network,reduce the failure rate of handoff between networks in outdoor visible light communication system,avoid ping-pong effect,and improve the communication performance of the system.