Space-Time Equalization for Asynchronous Multiuser Bit-Interleaved Coded OFDM

For a multiuser bit interleaved coded OFDM (BIC-OFDM) system, we study the methods of time domain equalization and per-subcarrier maximum likelihood (ML) frequency domain equalization when there is timing asynchronism among the users. For the time domain equalizer structure, a coded pairwise error probability (PEP) approximation is derived, which leads to a training-based space-time design method that takes the error rate performance into consideration. We compare the time domain equalization and per-subcarrier ML frequency domain equalization methods, and conclude that at high SNR´s, the time domain equalization approach is preferable.