Adaptive spectral precoding and modulation in OFDM

In this thesis, adaptive spectral precoding and modulation orthogonal frequency division multiplexing (ASP-OFDM) are proposed to improve the spectral performance. The coding order of the spectral prcoding and the modulation scheme, called the TX mode, are chosen in ASP-OFDM system. The average spectral efficiency of the transmitted signal with cyclic prefix (CP) or zero padding (ZP) is also considered. In constant power or variable power cases, the switching levels of adaptive TX mode are obtained under BER constraint. At last, we show the ASP-OFDM systems outperform AOFDM systems in average spectral efficiency.