Approaching the Matched Filter Bound with coded OFDM and SC-FDE schemes

Block transmission techniques, with appropriate cyclic prefixes and employing Frequency-Domain Equalization (FDE) techniques, have been shown to be suitable for high data rate transmission over severely time-dispersive channels. The most popular techniques based on this concept are Orthogonal Frequency Division Multiplexing (OFDM) and Single-Carrier with Frequency-Domain Equalization (SC-FDE). In this paper we consider OFDM and SC-FDE coded transmission schemes and we study the impact of the number of multipath components and the diversity order on their performance. It is shown for both schemes that when we have a high number of separable multipath components the asymptotic performance approaches the Matched Filter Bound (MFB), even without diversity. When we have diversity the performance approaches the MFB faster, even with a small number of separable multipath components. It was also observed that the SC-FDE has an overall performance advantage over the OFDM option, especially when employing the IB-DFE with turbo equalization and for a high code rate.