Rate Splitting Issue for Finite Length Raptor Codes

In this paper, we discuss the rate splitting issue for the design of finite length Raptor codes, in a joint decoding framework. We show that the choice of a rate lower than usually proposed for the precede enables to design Raptor codes that perform well at small lengths, with almost no asymptotic loss. We show in particular that the error floor can be greatly reduced by properly choosing the rate splitting between the precede and the LT code. Those behaviors are demonstrated both on the BEC and the BIAWGN channel.