Optimization of generalized LT codes for progressive image transfer

Rateless codes allow a user to incrementally send additional redundancy, so they can be useful for heterogeneous and time-varying networks for which the choice of redundancy level in advance is difficult. Rateless codes are an attractive application layer forward error correction solution due to their flexibility and capacity-approaching performance. The original rateless codes were developed for the delivery of equally important information. In many multimedia applications, some data symbols are more important than others. Unequal error protection (UEP) designs are attractive solutions for such transmissions. However previous UEP rateless code designs were aimed for coarsely layered sources and might exhibit poor performance for fine-grained progressive coding. The main objective of this paper is to introduce a more generalized coding scheme, parameters of which can be tailored for progressive multimedia transmission. We present the optimization of a generalized rateless code using two different progressive source transmission protocols. Proposed coding scheme is shown to exhibit better unequal protection and recovery time properties than other published results.