Research On Receiver Diversity Techniques For Visible Light Communication Equipped Vehicles

Recently,Internet of vehicles(Io V)have attracted extensive attention in the research community.Vehicles can communicate with others by Vehicle to Vehicle(V2V)and Vehicle to Infrastructure(V2I)technologies in Io V.Bringing great changes to transportation systems and driving experience,Io V have higher requirements for communication systems in the meantime since numerous applications require both real-time and reliable data delivery.Meanwhile,with the widespread use of the Light Emitting Diode(LED)in the manufacturing of vehicle lights and traffic lights,LED-based Visible Light Communication(VLC)has been regarded as an alternative complementary technique for data transmission for connected vehicles.However,it is noteworthy that VLC for connected vehicles is non-uniform and dynamic.In the VLC equipped vehicles,the distribution of the luminous intensity of vehicle-mounted LEDs,the received optical power and vehicles are all non-uniform,and all of the spatial relationship between the receiver and the transmitter,the VLC channel Direct Current(DC)gain and the performance of VLC change constantly with vehicle motion.Specifically,the vehicle-mounted VLC will be interrupted,if the angle of incidence is beyond the Field of View(FOV)of the receiver or the VLC link is blocked by other vehicles.To enhance the performance of VLC equipped vehicles,we propose to integrate receiver diversity techniques with VLC equipped vehicles.In the second chapter,we research on vehicle-mounted VLC channel.In order to analyze the vehicle-mounted VLC channel DC gain,we propose the spatial relationship model which takes the position and the posture of the receiver into consideration.According to the presented spatial relationship model we describe V2 V VLC model and V2 I model.In the third chapter,firstly,we study the receiver spatial and angular diversity for vehicle-mounted VLC.We present a layout scheme for receivers.In the presented scheme,we can not only achieve diversity gains but also obtain a wide FOV,which means the cover range of VLC can be enlarged and the outage probability can be reduced.Then,we research on the cooperative diversity for vehicle-mounted VLC.We project a scheme for choosing the cooperative partner,and a method to judge whether the VLC link is blocked by other vehicles or not.The cooperative partner is selected according to the VLC channel DC gain and the blockage judgement result in the proposed scheme.In the fourth chapter,we simulate and analyze vehicle-mounted VLC systems integrated with receiver diversity technique.Simulation results demonstrate that both receiver spatial and angular diversity technique and cooperative diversity can significantly decrease the Bit Error Rate(BER)of VLC.Furthermore,the receiver spatial and angular technique can decrease the probability of VLC interruption caused by the too large incidence angle which is beyond the FOV of the receiver.Not only can the cooperative diversity technique reduce the probability of VLC interruption caused by the too large incidence angle,but also can decline the probability of VLC interruption due to the blockage.