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 broadcast-ing applications where users may experience variable chan-nel conditions and packet loss rates, such as mobile en-vironments. Luby Transform (LT) and Raptor codes are practical fountain codes with a capacity approaching per-formance 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 dis-tributed joint-source channel coding has been extensively studied lately, and with promising results. However, a sys-tematic treatise of the code design and optimization con-siderations 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 dissemi-nation protocols where carefully designed fountain codes can provide strikingly simple, yet robust solutions yielding both distributed source coding and channel coding gains. 1