A technique to reduce inefficiencies in self ICI cancellation based OFDM systems

Self intercarrier interference cancellation (ICI), a half rate repetition coding scheme, is a simple and efficient technique to reduce frequency errors in OFDM. However at higher fractional frequency offset values, normalized to subcarrier separation, the self ICI cancellation scheme can no longer provide the same performance. Further due to the simple structure of repetition code, the self ICI cancellation scheme alone cannot provide much immunity to channel interference. In this paper we combine a maximum likelihood estimation technique with that scheme to get better immunity for frequency errors at higher fractional frequency offset values. This paper also discusses the possibility of application of a bandwidth efficient coding scheme for the considered cancellation scheme, to obtain the immunity to channel interference without further reducing bandwidth efficiency.