The Impact of Cyclic Prefix Length in DMT on the PLC System Design

In this paper the impact of the cyclic prefix (CP) length in discrete multi-tone (DMT) modulation on the powerline communications (PLC) system capacity is analysed. CP values that are shorter than channel impulse response introduce intersymbol and interchannel interference, that are spectrally concentrated in the case of PLC channel. We show that a trade-off between eliminating interference and preserving spectral efficiency can be obtained, for the purpose of maximizing system capacity. Practical implication is that short CP length values can give good system performances, despite PLC channel long impulse response durations.