Tunnel visible light communication system utilizing nonlinear suppression technique

Abstract

Tunnel visible light communication (TVLC) technology with light emitting diode (LED) is a research hotspot in advanced wireless communication systems. However, how to simultaneously improve the spectrum efficiency and suppress the nonlinear issues of the LED sources are still challenges. Here, we proposed and numerically study a novel companding technique for discrete multitone modulation (DMT) TVLC system. The proposed technique is upon the modified hyperbolic tangent transform function which can enlarge the small signals and compress the big signals while keeping the average power invariant. The peak-to-average power ratio (PAPR) of the system can be dramatically decreased, meanwhile the DMT signal can be kept working in the linear region of the LED. Simulation results verify that the proposed companding technique is a promising nonlinear suppressing method for high performance TVLC system. A 4.1Gbps TVLC system is realized and the bit error ratio (BER) performance is improved to 5.74 × 10−6 without forward error correction (FEC).