OFDM and SCFDE performance comparison for indoor optical wireless communication systems

Single-carrier frequency domain equalization (SCFDE) modulation is a promising technique for highly dispersive channels in broadband wireless communications. Similar to OFDM (orthogonal frequency division multiplexing), SCFDE attach a cyclic prefix (CP) to the transmitted symbol to eliminate inter-carrier interference (ICI) and converts the convolution with the channel to circular convolution. However and unlike OFDM, SCFDE is essentially a single carrier system. Thereby, some of the major OFDM problems, such as high PAPR (peak to average power ratio), are inherently resolved. The high PAPR problem in OFDM and the resulting nonlinear distortions are shown to have significant impact on the performance of indoor optical wireless (OW) systems [1]. Hence, it is the aim of this paper to study the performance of SCFDE for indoor OW systems and compare the performance to OFDM system. It is shown that, indeed, OW SCFDE system has low PAPR as compared to the corresponding OFDM system. However, the performance of OW OFDM systems and their counterpart SCFDE systems are traded off for certain input signal powers and modulation orders.