Train-to-train(T2T)communication can provide protection for existing train-to-ground private network communication,and its channel characteristics directly affect the application of upper-layer communication technolog...Train-to-train(T2T)communication can provide protection for existing train-to-ground private network communication,and its channel characteristics directly affect the application of upper-layer communication technologies.In this study,based on the spatial distribution structure of railway operation scenarios and Fresnel zone theory,we propose a frequency allocation scheme for direct communication between tracking trains in flatland and long straight tunnel scenario.Then we use the estimation method of radio wave attenuation caused by rainfall to analyze the large-scale path loss fading of multi-band wireless channels.Furthermore,we derive the calculation equation of max Doppler frequency shift suitable for T2T communication and describe the multipath wave in the tunnel by ray tracing method to analyze small-scale fading.Simulation analysis shows that the Doppler shift value of T2T communication low frequency band is significantly lower than the frequency shift value of the train-to-ground communication under the same speed conditions.展开更多
To solve fast channel variations induced by the mobility of the vehicles and achieve effective and reliable vehicular communications,the non-orthogonal multiple access is applied to the vehicle to vehicle(V2V)pairs un...To solve fast channel variations induced by the mobility of the vehicles and achieve effective and reliable vehicular communications,the non-orthogonal multiple access is applied to the vehicle to vehicle(V2V)pairs underlaid vehicle to infrastructure(V2I)users to solve the downlink resource allocation.A geographic position-based clustering algorithm for V2V users is proposed.The base station preassigns the channel resources and the Kuhn-Munkres algorithm is used to complete the channel assignment.Then,the verified particle swarm optimization(PSO)is adopted to achieve the optimal power allocation.The simulation results show that the proposed scheme outperforms the existing device to device(D2D)mechanism by improving the network connectivity,spectrum efficiency and data transmission rate.展开更多
基金National Natural Science Foundation of China(No.61763023)Lanzhou Jiaotong University-Tianjin University Innovation Fund(No.20180519)。
文摘Train-to-train(T2T)communication can provide protection for existing train-to-ground private network communication,and its channel characteristics directly affect the application of upper-layer communication technologies.In this study,based on the spatial distribution structure of railway operation scenarios and Fresnel zone theory,we propose a frequency allocation scheme for direct communication between tracking trains in flatland and long straight tunnel scenario.Then we use the estimation method of radio wave attenuation caused by rainfall to analyze the large-scale path loss fading of multi-band wireless channels.Furthermore,we derive the calculation equation of max Doppler frequency shift suitable for T2T communication and describe the multipath wave in the tunnel by ray tracing method to analyze small-scale fading.Simulation analysis shows that the Doppler shift value of T2T communication low frequency band is significantly lower than the frequency shift value of the train-to-ground communication under the same speed conditions.
基金The National Natural Science Foundation of China(No.61771126)the Key Research and Development Project of Jiangsu Province(No.BE2018108).
文摘To solve fast channel variations induced by the mobility of the vehicles and achieve effective and reliable vehicular communications,the non-orthogonal multiple access is applied to the vehicle to vehicle(V2V)pairs underlaid vehicle to infrastructure(V2I)users to solve the downlink resource allocation.A geographic position-based clustering algorithm for V2V users is proposed.The base station preassigns the channel resources and the Kuhn-Munkres algorithm is used to complete the channel assignment.Then,the verified particle swarm optimization(PSO)is adopted to achieve the optimal power allocation.The simulation results show that the proposed scheme outperforms the existing device to device(D2D)mechanism by improving the network connectivity,spectrum efficiency and data transmission rate.
