Recursive Clipping for Channel Estimation in VLC Systems
Abstract
Orthogonal frequency division multiplexing (OFDM) is extensively utilized in visible light communication (VLC) systems to achieve high rate transmission. This paper provides a new technique with two-step peak clipping (TSPC) scheme to specifically mitigate the high peak-to-average power ratio (PAPR) in clipped and pilot-aided optical OFDM in VLC system. The basic idea is to directly clip the peak power on the positions of pilots in the frequency domain before inserting the pilots’ symbols. The second step employs clipping the OFDM signal in the time domain. This may degrade the bit-error-rate (BER), therefore we have implemented channel estimation algorithm to enhance BER. Several algorithms for channel estimation have been investigated to verify the effectiveness of the proposed TSPC scheme in OFDM based VLC system. Simulation results show that our approach can effectively improve channel estimation and VLC system performance in terms of both PAPR reductions and BER performance.