Evaluation of the noise effects on Visible Light Communications using Manchester and Miller coding

This paper presents the investigation results concerning the negative effects of noise on the data signal in the case of Visible Light Communications (VLC). The motivation of this work was to offer a better understanding of the modifications of the data pulse in the presence of noise. Better understanding of the noise effect on the pulse width can help mitigate it and improve the communication performances. The paper also aims to make a comparative evaluation of two coding techniques used for outdoor VLC: the Manchester code as the code specified by the IEEE 802.15.7 standard in the case of outdoor applications using On-Off-Keying (OOK) modulation and the Miller code, as a possible alternative in Multi Input Multi Output (MIMO) applications. Simulations are performed on messages coded using the two codes for different levels of noise. It seems that in the case of digital signal processing (DSP), the Miller code pulse is less affected by distortions caused by noise. However, in the case of the Manchester code, the higher error tolerance compensates for the pulse distortions. Regarding the Bit Error Ratio (BER), the two codes exhibit similar performances.