ABSTRACT

In visible light communication positioning systems, when one light emitting diodes (LED) transmits its identification information, all the other LEDs emit constant light intensity for the illumination purpose. One disadvantage of Time division multiple access is that the synchronization is required, i.e., all the time slots of the transmitters should start at the same time and the receivers should also know the start time increasing the deployment cost. The difference between the presumed height and the actual height only affects the radius of those circles, i.e., all of the circles will expand or shrink at the same time. Therefore, the center of the intersection will remain almost unaffected. The vertical moving distance will be reduced if the sampling period decreases, contributing to higher positioning accuracy. The positioning algorithm is based on the received signal strength information detected from photodiode. Signal attenuation is calculated so that the distance between the transmitters and receiver is estimated.