VN-CodeSK Based Optical Fingerprint System With Non-Uniform Grid Interval According to µ-Law

One of the indoor positioning systems using visible light communication (VLC) is the optical fingerprint method. In this paper, the proposed optical fingerprint method uses a reference pattern characterized by non-uniformity. The non-uniformity depends on the µ-Law algorithm. It is showed the difference in positioning accuracy between the proposed method and the conventional one, which uses a uniform reference pattern. Furthermore, the optimal values for L and µ are investigated with VLC based on Variable N-Parallel Code Shift Keying (VN-CodeSK); where L is the distance between neighboring transmitters, µ shows the non-uniformity. The results show the variance of positioning error is improved and the maximum positioning error is greatly decreased using the proposed method. Moreover, according to the computer simulation, L=1.7[m] and µ=1.1 are optimal parameters in this model.