Link Performance of an CDMA-Based Time-of-Flight Ranging by Using LED Visible Light

The use of ranging sensors on automobiles is becoming common with the desire of traffic safety by providing drivers the information of the relative distance between the vehicles. In this paper, the LED visible light ranging system different from the conventional ranging systems using the RF signal is investigated. For such a system, we propose a novel ranging algorithm which combines the time-of-flight (TOF) with the CDMA technology. Via the CDMA technology, the TOF ranging system can accurately distinguish the desired ranging signal from the visible light interferences of the neighbor vehicles. In addition, the proposed system can also overcome the light noise from other luminaries, i.e. sun-light, traffic-light, and so on. The simulation results show that the CDMA-based LED ranging system has a significant improvement for the ranging accuracy compared with the case without employing the CDMA