Orthogonal Frequency Division Multiplexing (OFDM) is widely used in both wired and wireless broadband communications systems and has more recently been the subject of much research as a modulation technique in optical communications systems [1]. OFDM's popularity stems from its high bandwidth efficiency due to the compact arrangement of the overlapping, but orthogonal, subcarriers; additionally the inclusion of a cyclic prefix converts the time dispersive channel into a circular convolution facilitating the construction of a simple maximum likelihood equalizer in the frequency domain. The subcarrier orthogonality property ensures zero Inter Symbol (i.e. subcarrier) Interference (ISI) and importantly this property holds if and only if the channel remains linear. © 2011 IEEE.