Multilevel Codes for Unequal Error Protection of Progressive Source over Fading Channels

With emerging standards like JPEG2000 focusing on scalable encoding of images, there is an immediate need for robust schemes to transmit progressive source streams over error-prone fading channels. In this work, we explore one possibility for this framework, where we use multilevel codes with Low Density Parity Check (LDPC) component codes and an 8-PSK constellation. We match the channel code rates with the source rates in each sub-channel in an optimal fashion. Diierent overall code rates can be easily supported with the multilevel framework, and system performance can be maximized over varying average SNR scenarios by adaptive partitioning of the constellation. For each speciic system connguration, a simple optimization can be performed to maximize the received image quality by partitioning the source stream among the sub-channels in an R-D optimal way.