Figure 1
From: Self-organising interference coordination in optical wireless networks
Depiction of physical layer signal processing at the transmitter for data transmission using OFDM modulation in optical wireless system. To maintain real signal, a complex conjugate of baseband symbol applied on subcarrier k must be applied on subcarrier -k. Likewise, a DC bias is added to ensure that the signal is positive in order to transmit the signal using IM on subcarrers with index -Nsc/2 and 0.