Data is transmitted in the form of packets on the Internet. Due to various channel complexities, some packets may get lost and never reach their destination. Reliable transmission of data over the Internet is always desirable. Current networks that use mostly unicast -based protocols such as the transport control protocol TCP/IP and other unicast protocols place strong importance on the ordering of packets to simplify coding at the expense of increased traffic. An alternative approach is where packets are not ordered and the recovery of some subset of packets will allow for successful decoding. This class of such codes, called fountain codes, was pioneered by a startup called Digital Fountain and has greatly influenced the design of codes for binary erasure channels (BECs), a well-established model for the Internet [1]. This paper includes two fountain codes system models for packet recovery and bit error correction, a study of pre-codes of Raptor codes, and proposing a hybrid fast decoding algorithm to reduce the overheads of short and moderate-length LT codes.

LT codes Raptor codes error rate.