Optimization of operating BW for indoor optical wireless OFDM transmission with IM/DD

This paper quantifies the optimal utilized bandwidth (BW) of indoor optical wireless transmission using orthogonal frequency division multiplexing (OFDM) with intensity modulation and direct detection (IM/DD) by varying the number of transmitted bits per OFDM symbol. Due to its power efficiency, asymmetrically clipped optical OFDM (ACO-OFDM) is selected as a unipolar OFDM scheme. To further improve its power efficiency, ACO-OFDM is optimized through the bit loading technique where some target BER is fixed. For the transmission bit rates of 20 and 30 Mbps, the optimal operating BW is identified based on the required transmit optical power, and is neither the smallest nor the largest in the considered range of BW in which the cyclic prefix (CP) length is sufficient to avoid intersymbol interference (ISI) and inter-carrier interference (ICI).