1 Department of Electronic Systems, The Technical Faculty of IT and Design, Aalborg University, VBN2 The Faculty of Engineering and Science (TECH), Aalborg University, VBN3 Antennas, propagation and radio networking, The Technical Faculty of IT and Design, Aalborg University, VBN4 Multimedia Information and Signal Processing, The Technical Faculty of IT and Design, Aalborg University, VBN
In this paper we propose a new design of LT codes, which decreases the amount of necessary overhead in comparison to existing designs. The design focuses on a parameter of the LT decoding process called the ripple size. This parameter was also a key element in the design proposed in the original work by Luby. Specifically, Luby argued that an LT code should provide a constant ripple size during decoding. In this work we show that the ripple size should decrease during decoding, in order to reduce the necessary overhead. Initially we motivate this claim by analytical results related to the redundancy within an LT code. We then propose a new design procedure, which can provide any desired achievable decreasing ripple size. The new design procedure is evaluated and compared to the current state of the art through simulations. This reveals a significant increase in performance with respect to both average overhead and error probability at any fixed overhead.
Ieee Transactions on Communications, 2012, Vol 60, Issue 11, p. 3191-3197