A new loading algorithm for image transmitting over spectrally shaped channels: combined source coding and multicarrier modulation approach

A combined source coding and multicarrier modulation scheme for transmitting image over noisy channels is proposed. The source image is divided into several layers which are transmitted in parallel, each occupying a number of subchannels. For spectrally shaped channels, the existing loading algorithms try to remove the property that channel gain and noisy variance are quite different across the subchannels, and use the power and rate allocation to provide an uniform error performance at the usable subchannels. In contrast, we deem the above property as an advantage and develop a new loading algorithm to provide unequal error protection as well as achieve better power efficiency. For subband coded images transmission, simulations show that the proposed algorithm achieves significant performance improvement, especially, 4-10 dB improvement over the existing algorithms for typical spectrally shaped channels.