Single Carrier Modulation with Frequency Domain Equalization for Intensity Modulation-Direct Detection Channels with Intersymbol Interference

In this paper, we examine single carrier modulation with frequency domain equalization (SC-FDE) for optical communication systems using intensity modulation with direct detection (IM/DD) in the presence of additive white Gaussian noise. SC-FDE is a technique whose processing is quite similar to that of OFDM. Unlike OFDM, however, SC-FDE is compatible with IM/DD channels because it does not require the transmission of a strong dc. For an IM/DD channel, at high data rate regime, the effect of intersymbol interference (ISI) starts to dominate system performance. In this paper, we examine the use of SC-FDE and pulse position modulation (PPM) to combat ISI for IM/DD channels. Such a system enjoys the average power efficiency of PPM and the low complexity equalization of SC-FDE. We analyze the bit error performance of SC-FDE and compare it with a few known techniques