An efficient way to reduce the peak-to-average power ratio (PAPR) in OFDM systems is clipping. After the clipping in an MIMO-OFDM system, the additive noise may not be white. In this chapter, we develop fast (single-symbol) maximum likelihood (ML) decoding algorithms for orthogonal space-time block codes (OSTBC) and (linearly transformed) quasi orthogonal space-time block codes (QOSTBC) in clipped MIMO-OFDM systems by using a clipping noise model with Gaussian approximation. By using the statistics of the clipping distortions, our newly developed fast ML decoding algorithms improve the performance for clipped MIMO-OFDM systems with OSTBC and QOSTBC while the decoding complexities are not increased. Simulation results are presented to illustrate the improvement.
Keywords: PAPR, MIMO-OFDM, orthogonal space-time block code, space time block code, clipping
