Residual Clipping Noise in Multi-layer Optical OFDM: Modeling, Analysis,
and Application
Abstract
Optical orthogonal frequency division multiplexing (O-OFDM) schemes are
variations of OFDM schemes which produce non-negative signals.
Asymmetrically-clipped O-OFDM (ACO-OFDM) is a single-layer O-OFDM
scheme, whose spectral efficiency can be enhanced by adopting multiple
ACO-OFDM layers or a combination of ACO-OFDM and other O-OFDM schemes.
However, since symbol detection in such enhanced ACO-OFDM (eACO-OFDM) is
done iteratively, erroneous detection leads to residual clipping noise
(RCN) which can degrade performance in practice. Thus, it is important
to develop an accurate model for RCN which can be used to design
RCN-aware eACO-OFDM schemes. To this end, this paper provides a
mathematical analysis of RCN leading to an accurate model of RCN power.
The obtained model is used to analyze the performance of various
eACO-OFDM schemes. It is shown that the model provides an accurate
evaluation of symbol error rate (SER), which would be underestimated if
RCN is ignored. Moreover, the model is shown to be useful for designing
an RCN-aware resource allocation that increases the robustness of the
system in terms of meeting a target SER, compared to an RCN-unaware
design.