Multiple access scheme based on block encoding time division multiplexing in an indoor positioning system using visible light

In view of the application of a visible light positioning system in a public indoor environment with numerous light emitting diodes (LEDs), a long delay is one of the main factors that limits the performance of the positioning systemwith a moving device. To solve this problem, a multiple access scheme based on block encoding time division multiplexing (TDM) is proposed in this paper. In our scheme, nine LEDs compose one block to reduce the system delay. Meanwhile, in order to reduce intercell interference, an extended binary coded decimal code is used to encode signals transmitted by LEDs. The feasibility and performance of the scheme is demonstrated by simulations. The results show that the proposed TDMscheme provides a better performance than the conventional TDM and is more applicable to the accurate positioning of a moving device.