Network Coded Multiple Access Enhanced Vehicular Visible Light Communications

Visible light communications (VLC) have demonstrated its Electro-magnetic Interference (EMI) immune capability for truck platooning for intelligent transportation in Japan's highway. However, practical traffic scenarios like lane change may lead to the decrease of reliability between two vehicles due to imperfect alignment such as lateral shift and angle offset, which is an important issue in Vehicle to Vehicle VLC (V2V-VLC) systems. Especially in systems that utilizing multiple Light Emitting Diodes (LEDs) to transmit multiple spatial streams, this issue in the reliability will reduce the throughput of the system. In this paper, we propose a Network Coded Multiple Access (NCMA) enhanced V2V-VLC system to improve the performance of the system transmitting two spatial streams. Compared to conventional system, the proposed V2V-VLC system can improve the average normalized throughput in lane change scenario by 28%, 32%, 26% and 12% at the signal-to-noise ratio (SNR) of 5 dB, 6 dB, 7 dB and 8 dB, respectively.