Maximum likelihood inter-carrier interference suppression for wireless OFDM with null subcarriers

Orthogonal frequency division multiplexing (OFDM) transmission is robust to frequency-selective channels but sensitive to time-selective channels. Time variations of channels destroys the orthogonality between subcarriers, resulting in a considerable performance loss due to intercarrier interference (ICI) between subcarriers. In this paper, we propose a Viterbi-type algorithm to effectively suppress the ICI, by exploiting the property of ICI terms and null subcarriers embedded in OFDM symbols for the reduction of interferences from/to adjacent bands. Simulations show that the proposed equalizer works well with affordable complexity and outperforms linear equalizers.