Constellation Collaborated OFDM for Visible Light Communication Systems

In visible light communication (VLC) systems based on LEDs, the limited modulation bandwidth of LEDs is a major challenge in achieving high-speed data transmission. To attain better performance on the low-pass frequency-selective fading channel, a constellation collaborated orthogonal frequency amplitude multiplexing (OFDM) is proposed in this letter. In this novel OFDM, each two subcarrier frequencies are chosen as a pair. The symbols on the two subcarrier frequencies are respectively chosen from two uniquely factorable constellation pairs (UFCPs), with one random bit acting as a coordinator to control the two symbols. Simulation comparisons demonstrate that the proposed constellation collaborative OFDM systems can attain 0.8-1.5 dB SNR gain over conventional OFDM systems.