Analysis and Mitigation of Clipping Noise in Layered ACO-OFDM Based Visible Light Communication Systems

• Published in: IEEE transactions on communications Vol. 67; no. 1; pp. 564 - 577
• Main Authors: Wang, Thomas Q., Li, Hang, Huang, Xiaojing
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptive optics; Attenuation; Bit error rate; decision aided reconstruction; deliberate digital clipping; intensity modulation direct detection; Layered ACO-OFDM; Noise; Nonlinear distortion; OFDM; Optical communication; Optical components; Optical distortion; Optical saturation; Orthogonal Frequency Division Multiplexing; Receivers; Symbols; visible light communications
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2018.2868665

Due to the limited dynamic range of the off-the-shelf electrical and optical components, deliberate digital clipping (DDC) is widely applied to optical orthogonal frequency division multiplexing (OFDM) based visible light communication systems. In this paper, we present a theoretical characterization of the layered asymmetrically clipped optical OFDM (ACO-OFDM) signals subject to peak clipping. We decouple a clipped <inline-formula> <tex-math notation="LaTeX">L </tex-math></inline-formula>-layer ACO-OFDM symbol to <inline-formula> <tex-math notation="LaTeX">L </tex-math></inline-formula> single-layer ACO-OFDM symbols, each corresponding to a layer, and show that these symbols are subject to symmetrical peak clippings at random levels. Using Bussgang's theorem, the resulting attenuation factors and variances of the additive noise associated with each layer are derived. It is shown that the clipping noise caused by the DDC mainly falls onto the first layer, and its impact is gradually reduced in the subsequent layers. In order to combat the clipping noise, a novel receiver based on decision aided reconstruction is proposed. Simulation results show that the proposed receiver can effectively mitigate the clipping noise, leading to significant improvement of bit error rates over the conventional receiver.