Pilot symbol utilization for reducing peak-to-average power ratio in optical OFDM

Abstract

One of the evolved technologies which has the prospect of providing huge data rate is visible light communication (VLC). Use of optical orthogonal frequency-division multiplexing (OFDM) has been demonstrated as one of the viable schemes in achieving high data rate in VLC system. However, the limitation of optical OFDM still remains the high peak-toaverage power ratio (PAPR) which results in signal distortion and increase in error rate. In this paper, we describe a technique that can mitigate high PAPR in optical OFDM using pilot symbol in the indoor VLC environment. The pilot assisted OFDM system gives 2.4 dB PAPR reduction for a 4-QAM. There is indication from the simulation results that not only can the technique reduce high PAPR but it also offers good bit error rate (BER) performance. For the BER performance of 64-QAM, the pilot symbol estimation error leads to about 0.6 dB degradation at BER of 10 −3 .

PAPR reduction in optical OFDM with grouped LEDs

“…Also, θ ip represents the phase of the i th pilot symbol which is either 0 or π to ease data recovery at the receiver and maintain the original signal constellation. The amplitude of the pilot symbol |X p (i)| = 1 for the purpose of preserving the data signal electrical power [18]. Hermitian symmetry is imposed on the PA O-OFDM frame X sp .…”

“…The pilot symbol estimation and transmitted data symbol recovery at the receiver remains the same as described in Section III-A. Furthermore, details of the performance of the PA technique in a correlated indoor VLC channel can be found in [9], [18].…”