Design of expanding window fountain codes with unequal power allocation over BIAWGN channels

Abstract

In this study, the authors propose an improved design of expanding window fountain (EWF) codes over the binary input additive white Gaussian noise channels. The encoding process is modified to get almost regular variable-node degree distributions. Compared with the conventional EWF codes, their proposed scheme can lower the error floor. Furthermore, they combine the EWF encoding process with unequal power allocation to improve unequal error protection (UEP) performance, and construct pre-coded EWF codes by concatenating their proposed EWF codes with high-rate low-density parity-check codes. Both asymptotic analysis and simulation results show that, compared with the conventional scheme, their proposed scheme can get better UEP performance and design flexibility.