Service-driven Approximate LT Codes

Luby Transform (LT) codes are becoming increasingly important in transmission due to the ability to protect the source data in high reliability economically. LT codes generate rateless packets on-the-fly through randomly chosen encoding degree, so it cannot control or manage the service quality according to distinct service demands of clients. In this article, we extended LT codes with a service-driven control policy. The proposed encoder arranges the encoding degree through the basic building structures via various control policies to fulfill the requests of majority of clients. With the proposed control policies in the multicasting or broadcasting channel, source data of most clients can be recovered as soon as possible. Besides, comparing to LT codes in point-to-point protocol, the proposed codes also introduce lower decoding overhead, better intermediate performance, and built-in unequal error protection property through appropriately arranging the placements of source data in the coding graph.