Blind frequency offset estimation combine with decoder for BICM-OFDM system

The combination of orthogonal frequency division multiplexing (OFDM) and bit-interleaved coded modulation (BICM) is known as an efficient technique to combat frequency selective channels. In BICM-OFDM systems, significant performance degradation can result from carrier frequency offset, which caused Inter Carrier Interference (ICI). Based on the analysis of the frequency offset in OFDM, a new blind frequency offset estimation algorithm which associates with the decoder is proposed. This algorithm needs only one OFDM symbol. The feedback information provided by BICM is regarded as virtual training sequence. Using the correlation between the feedback information and received signals, the frequency offset can be estimate. Furthermore, the precision of estimation could be improved by the feedback information provided by iterative decoder of BICM. The simulation results show that, the proposed algorithm efficiently estimates frequency offset after three iterations.