Full-diversity group space-time-frequency (GSTF) codes from cyclic codes

Optimum Subcarrier Grouping and Rotation Matrix for Coded OFDM with Modulation Diversity

“…Modulation diversity (MD) can provide performance improvement over fading channels by increasing the diversity order of a communications system [1], [2]. Applications of MD have been considered in various uncoded orthogonal frequency-division multiplexing (OFDM) systems over frequency-selective fading channels [3]- [6]. For instance, subcarrier grouping was originally introduced in [5] for singleantenna OFDM with linear constellation precoding to achieve maximum multipath diversity and coding gains while significantly reducing the receiver complexity.…”

“…For instance, subcarrier grouping was originally introduced in [5] for singleantenna OFDM with linear constellation precoding to achieve maximum multipath diversity and coding gains while significantly reducing the receiver complexity. This technique is then applied to various uncoded OFDM systems [3], [4], [6]. Surprisingly, to date, the solution for subcarrier grouping has not been solved explicitly.…”

On Subcarrier Grouping for OFDM with Linear Constellation Precoding

“…Applications of constellation precoding have been considered for various orthogonal frequency-division multiplexing (OFDM) systems operating over frequency-selective fading channels [3][4][5][6]. In particular, it is shown in [3] that the use of linear constellation precoding (LCP) with a specifically chosen subcarrier grouping can achieve the maximum multipath diversity and coding gains as with precoding over all the available subcarriers.…”

“…When F > L, it is not known if the subcarrier grouping in [3] can achieve the maximum diversity and coding gains. It should be pointed out that the subcarrier grouping scheme proposed in [3] has been applied to various OFDM systems [4][5][6], but surprisingly, without the full understanding of its merit.…”