A Visible Light Single-Carrier Frequency Domain Equalization Based On Mobile Localization

Recent years,visible light communication has become a research hotspot in the field of optical communication due to its environmental protection and rich spectrum resources.However,a longterm bottleneck has been existing for a long time: the separation of communication and positioning technology.In other traditional wireless communication technologies,there is a complementary relationship between positioning and communication technology.Dealing with the problem that the indoor visible light communication system has serious inter-symbol interference,the positioning technology can be used to assist the equalization technology to achieve better communication effects.The equalization technology of the indoor visible light receiving end has been studied in this paper.Firstly,the common equalization techniques of indoor visible light communication is introduced and compares their advantages and disadvantages.Then,the indoor visible light communication model is analyzed and the single-carrier frequency domain equalization is carried out by combining positioning and equalization under this model.The zero-forcing equalization and the MMSE(Minimum Mean Squared Error)algorithm are discussed.It shows that the frequency domain MMSE equalization effect based on position information is better than the zero-forcing equalization.Based on different positioning errors,the proportion of the normal and equalization communication area in the room is calculated.The simulation results show that even if the positioning error occurs,the proposed location information based equalization technique is still better than the non-equalization.Finally,for the characteristics of intensity modulation/direct detection in visible light communication,a single-carrier frequency-domain transform using DHT(Discrete Hartley Transform)is proposed,which is suitable for real numbers.Compared with the traditional Fourier transform,this method has a smaller computational complexity.Since both forward and reverse transforms are performed in the real field and all of them used the same transform method so the complexity of the hardware can be reduced.