Improved Joint ICI Cancellation and Error Correction for OFDM System

Orthogonal Frequency Division Multiplexing (OFDM) is attractive for high data rate transmission due to spectral efficiency but is known to be sensitive to synchronization errors(symbol time and frequency offset)[1]. Mobility is the basic feature of most of present day techniques that employs OFDM at the backend but Doppler frequencies generated due to the mobility causes frequency offsets which results in Inter Carrier Interference (ICI) amongst the subcarriers of the multicarrier OFDM technique. It induces cross talk and causes deterioration of signal. This paper proposes an efficient Frequency-domain ICI mitigation technique based on the estimation of channel taps to vanish the effects of channel frequency offsets from the proposed OFDM model. Along with this, the channel induced noise tend to raise the BER of the OFDM system making it unsuitable for many error-sensitive applications. Turbo codes have been integrated into the resulting system to cater-for the effects of channel induced noise. MAP decoding algorithm applied at the receiving end is based on the exchange of soft information amongst the component decoders that gain from eachother's interleaved extrinsic information. The signal is passed through multipath Rayleigh fading AWGN channel and the performance is measured.