Transmission of DCT-coded images by multicarrier modulation for noisy channels

We have proposed and analyzed a combined source-channel coding scheme using multicarrier modulation. By changing the power and modulation of subchannels carrying different bits of the quantized signal, the channel-induced distortion can be minimized. An algorithm for the subchannel power allocation is derived. For discrete cosine transform (DCT) coded images, multicarrier systems achieve more than a 9-dB improvement over single-carrier systems on very noisy channels.