Affine preceding superimposes training signals on linearly precoded data. It enhances symbol recovery and effectively identifies the frequency-selective fading channel. Previous works have shown its advantage over the standard time-multiplexed training. This paper considers orthogonal affine precoding for joint channel estimation and symbol detection in wireless MIMO-OFDM systems. Analytical and numerical results confirm its ability to efficiently identify the unknown wireless channel as well as effectively recover the data symbols, while conserving the transmission bandwidth.