Low complexity EM-based decoding for OFDM systems with impulsive noise
Modern OFDM systems such as cellular LTE and powerline communications experience additive impulsive noise emitted from their environment. OFDM modulation has been shown to provide resilience to impulsive noise due to its code diversity. However, typical OFDM receivers designed under the Gaussian noise assumption will lead to suboptimal performance due to the dependence in noise statistics across subcarriers resulting from the FFT operation. As a result, optimal detection of OFDM symbols becomes prohibitive due to its exponential complexity. We consider the design of a practical class of OFDM receivers that are constrained to perform independent detection on each subcarrier. In this paper, we propose an EM based low-complexity iterative decoding algorithm for OFDM systems in impulsive noise environments that preserves the independent decoding across subcarriers. We validate its performance under typical impulsive noise conditions based on noise traces collected from wireless and powerline platforms. Our proposed method achieves a gain between 2 – 7dB over the conventional OFDM receiver depending on the SNR range.