Low complexity intercarrier interference reduction techniques for OFDM systems

In OFDM systems, fast channel variation leads to the loss of orthogonality between the subcarriers. This results in intercarrier interference which cannot be mitigated with conventional single-tap equalization, and hence more complex equalization techniques are required. We seek in this paper low complexity interference equalization (linear in FFT size). Whereas successive interference cancellation targets removing the interference with previously detected symbols, we aim at reducing the interference with the other symbols prior to detection. Based on a proposed channel modeling and approximation procedure, we develop two low-complexity interference reduction techniques that reduce the remaining intercarrier interference significantly. The first targets maximizing the average SINR (Signal to Interference + Noise Ratio), whereas the second is based on minimizing the mean squared error. We compare these 2 methods using Monte Carlo simulations, and demonstrate their effectiveness compared to other methods of similar order of complexity.