Unique word-orthogonal frequency division multiplexing (UW-OFDM) is a novel signaling concept wherethe guard interval is implemented as a deterministic sequence, the so-called unique word. The UW isgenerated by introducing a certain level of redundancy in the frequency domain. Different data estima-tion strategies and the favourable bit error ratio (BER) performance of UW-OFDM, as well as comparisonsto competing concepts have already extensively been discussed in previous papers. This work focuseson the different possibilities on how to generate UW-OFDM signals. The optimality of the two-step overthe direct approach in systematic UW-OFDM is proved analytically, we present a heuristic algorithm thatallows a fast numerical optimization of the redundant subcarrier positions, and we show that our originalintuitive approach of spreading the redundant subcarriers in systematically encoded UW-OFDM by min-imizing the mean redundant energy is practically also optimum w.r.t. transceiver based cost functions.Finally, we derive closed form approximations of the statistical symbol distributions on individual sub-carriers as well as the redundant energy distribution and compare them with numerically found results.
Sprache der Kurzfassung:
International Journal of Electronics and Communications (AEÜ)