Rateless Distributed Source Code Design

Over the past decade, rateless codes, i.e., digital fountain codes, have emerged as an efficient and robust solution for reliable data transmission over packet erasure networks and a particularly suitable one for multicasting and broadcasting applications where users may experience variable channel conditions and packet loss rates, such as mobile environments. Luby Transform (LT) and Raptor codes are practical fountain codes with a capacity approaching performance and a low computational cost. In addition to their channel coding applications, the use of fountain codes for various kinds of distributed source compression and distributed joint-source channel coding has been extensively studied lately, and with promising results. However, a systematic treatise of the code design and optimization considerations for such non-standard applications of fountain codes is still absent. In this contribution, we overview the main results concerned with rateless codes for distributed source coding and outline several examples of data dissemination protocols where carefully designed fountain codes can provide strikingly simple, yet robust solutions yielding both distributed source coding and channel coding gains.