Some Results on Joint Iterative Channel Equalization and Turbo Decoding for OFDM Systems

The use of turbo/LDPC channel coding in wireless communication systems opens new avenues as far as the optimization of other signal detection functions are concerned. For instance, channel estimation/equalization may greatly benefit by the presence of high-efficiency channel coding with iterative decoding. In this paper we assume multicarrier (OFDM) transmission on a (time-invariant) frequency-selective wireless channel, and we show how to integrate soft-output iterative detection with (iterative) channel estimation. The conventional approach to channel estimation relies on pilot symbols suitably inserted in the data frame. We show here how to use the soft outputs produced by the iterative decoder at each iteration to "supplement" the pilot symbols and aid the function of channel estimation and equalization.