Experimental Investigation of Zadoff-Chu Matrix Precoding for Visible Light Communication System with OFDM Modulation

Xinyue Guo,Shuangshuang Li,Yang Guo

doi:10.1155/2018/5173285

Abstract

Light-emitting diode- (LED-) based visible light communication (VLC) has become a potential candidate for next generation high-speed indoor wireless communication. Due to the limited modulation bandwidth of the LED, orthogonal frequency division multiplexing (OFDM) modulation is particularly preferred in the VLC system to overcome the ISI, which suffers from the high peak-to-average power ratio (PAPR) and leads to severe performance loss. In this paper, we propose and experimentally demonstrate a novel Zadoff-Chu matrix (ZCM) precoding scheme, which can not only reduce the PAPR, but also provide uniform signal-to-noise ratio (SNR) profile. The theoretical analysis and simulation show that the proposed scheme achieves better PAPR performance compared with the traditional precoding schemes. The experimental demonstration further validates the bit error rate (BER) performance improvement, where the measured BERs are all below the 7% pre-forward error correction (pre-FEC) limit of 3.8 × 10−3 when the transmitted data rate is 50 Mb/s.

Highlights

Visible light communication (VLC) has recently emerged as a compelling wireless communication technology beyond traditional radio frequency (RF) communications
We propose and experimentally demonstrate a novel Zadoff-Chu matrix (ZCM) precoding based Orthogonal frequency division multiplexing (OFDM) VLC system
Through the theoretical analysis and the computer simulation, we reach the conclusion that the ZCM precoding scheme achieves the same peak-to-average power ratio (PAPR) performance as the discrete Fourier transform (DFT) precoding scheme, but much better than the traditional WalshHadamard matrix and the orthogonal circulant matrix transform (OCT) precoding schemes

Summary

Introduction

Visible light communication (VLC) has recently emerged as a compelling wireless communication technology beyond traditional radio frequency (RF) communications. The iterative clipping and exponential nonlinear companding methods are other ways to reduce PAPR in VLC systems [9, 10] Both methods mentioned above can result in the bit error rate (BER) performance degradation. In [14, 15], the Walsh-Hadamard matrix and the discrete Fourier transform (DFT) operation have been used as precoding matrices to decrease the PAPR of the OFDM signals Both results confirm that the PAPR can be reduced significantly. In [16], an orthogonal circulant matrix transform (OCT) based precoding scheme is proposed, which achieves a relatively flat signal-to-noise ratio (SNR) profile over the signal bandwidth and alleviates significant BER degradation at high frequency carriers. Experimental results indicate that the ZCM precoding scheme achieves the best BER performance, where the measured BERs are all below the 7% pre-forward error correction (pre-FEC) limit of 3.8 × 10−3 with 50Mb/s transmission data rate and 1-meter transmission distance

Principle

6.25 MHz 16QAM

Experimental Results

Conclusion