UW-OFDM over long tap delay channel with a concatenated channel estimation technique

Unique Word OFDM (UW-OFDM) is a new technique for constructing OFDM symbols and it can offer a better bit error rate performance than conventional OFDM systems. Where the unique word is used as a guard interval. In OFDM system to avoid inter-block interference and improve the bit error rate performance guard interval is selected to be longer than the largest expected channel delay spread. Unfortunately, that will significantly reduce the system bandwidth in the long delay spread channels such as underwater channel. In this paper, UW-OFDM is proposed for such long tap delay channel with an efficient channel estimation technique to improve system performance. The proposed method, use the least square channel estimation technique to estimate number of efficient channel taps, then orthogonal matched pursuit (OMP) compressed sensing provides a perfect channel estimation. Simulation results show that UW-OFDM based on the proposed scheme with insufficient guard interval length can indeed offer significant bit error rate performance.