In this paper, we introduced concept of unique word orthogonal frequency division multiplexing (UW-OFDM). In UW-OFDM instead of conventional cyclic prefixes (CPs) we use deterministic sequence, which we called unique word (UW’s), as a guard interval. Since Unique word represent known sequence they are advantageously be used for synchronization and channel estimation purposes. The UW’s are generated by approximately loding so called redundant subcarrier. We derived optimum complex valued code generator matrices matched to best linear unbiased estimator (BLUE) and to linear minimum mean square error (LMMSE) data estimator. With the help of simulations we highlight the superior bit error ratio (BER) performance of non-systematic coded UW-OFDM compared to systematic coded UW-OFDM and to CP-OFDM in additive white Gaussian noise (AWGN) as well as in frequency selective environments.
Keywords
Cyclic Prefix (CP), Reed-Solomon Coded OFDM, Unique word OFDM (UW-OFDM), Best linear unbiased estimator (BLUE), Linear minimum mean square error (LMMSE)
