Abstract:
A visible light communication (VLC) system would be an excellent choice for indoor
downlink access and data transmission and it is often done by intensity modulation
and direct detection (IM/DD), in which the electrical signal must be turned into a
real-valued and nonnegative waveform in order to drive light emitting diodes (LEDs).
Conventional forward error correction (FEC) codes can not provide two lighting related
features, dimming support and flicker mitigation. Because of the narrow bandwidth of
LEDs and the existing coding approaches, transmission efficiency and error correction
performance are low. In this research, the BER performances of the BPSK, 4-QAM
and 16-QAM asymmetrically clipped optical orthogonal frequency division multiplexing
(ACO-OFDM) signal with polar code and flicker mitigation using Manchester coding
are investigated over VLC channel. To increase the transmission capacity and error
control performance of a VLC system, ACO-OFDM and cyclic redundancy check
aided successive cancellation list (CRC-Aided-SCL) are used, which provide significant
error-correction performance in the regime of low signal to noise ratio (SNR). The
simulation result show that the CRC-Aided-SCL algorithm achieved BER of 10
−5
and
run length value of 2 with optical clock rate of 0.1MHz using Manchester coding while
the spectral efficiency (SE) was 13.15, 13.38 and 13.6 bps/Hz for BPSK, 4-QAM and
16-QAM, respectively. We also compared the complexity of SCL and SC algorithm and
obtained 18432 and 4608,respectively, using list size 4 and N=256 without consideration
of iteration. Generally, the error control performance can be increased by polar code
and better transmission efficiency by ACO-OFDM is achieved.
Keywords: ACO-OFDM, CRC-Aided-SCL, Flicker mitigation, VLC.