Linear constellation-precoding for OFDM with maximum multipath diversity and coding gains

This paper introduces linear constellation precoding (LCP) for OFDM transmissions over frequency-selective fading channels. Exploiting the correlation structure of OFDM subchannels, and choosing system parameters properly, we first perform optimal subcarrier grouping to divide the set of correlated subchannels into subsets. Within each subset, a non-redundant constellation-specific unitary precoder is then designed to achieve maximum multipath diversity and coding gains. While greatly reducing the decoding complexity and simplifying the LCP design, subcarrier grouping offers optimal performance by maximizing multipath diversity and coding gains. In addition, the proposed system does not sacrifice the transmission rate. Analytic evaluation and corroborating simulations reveal its performance merits.