Approaching the Matched Filter Bound with Unique Word OFDM

In this work, we consider a bit-interleaved coded modulation unique word (UW) OFDM system with turbo equalization. For such a system, only a limited performance improvement over the turbo iterations was observed in a previous work. This is because interleaving was limited to one UW-OFDM symbol, which causes dependencies between the log-likelihood ratios exchanged between the equalizer and the decoder. To overcome this issue, we propose interleaving beyond one UW-OFDM symbol. Moreover, through bit error ratio simulations we determine the minimum number of UW-OFDM symbols across which interleaving should be performed to reach the matched filter bound (MFB).