Interference-Free Hybrid Optical OFDM With Low-Complexity Receiver for Wireless Optical Communications

In optical wireless communication (OWC), conventional superimposed optical orthogonal frequency division multiplexing (OOFDM) techniques, such as hybrid asymmetrically clipped OOFDM (HACO-OFDM), require an additional operation of interference cancellation to decode transmitted symbols, which leads to relatively high receiver complexity with processing delay. In this letter, we propose a novel superimposed OOFDM scheme with low-complexity receiver, named as interference-free hybrid OOFDM (IFHO-OFDM), for OWC. In the proposed IFHO-OFDM, two hybrid OOFDM components are combined for simultaneous transmission to achieve the appealing advantages of high spectral efficiency, and a time-selective bias is designed to guarantee the non-negativity while maintaining high power efficiency. Moreover, we propose to superimpose the two hybrid OOFDM components in an interference-free way, and thus, it can be readily demodulated by a standard low-complexity OFDM receiver. Simulation results verified the superiority of the proposed IFHO-OFDM in terms of both peak-to-average-power ratio (PAPR) and bit error rate (BER) compared to HACO-OFDM.