Improved Design Criteria for Duplicate LT Codes

In this paper, we propose an efficient scheme to construct LT codes that can provide unequal error protection (UEP) property. We implement low rate LDPC codes instead of the duplication and utilize a low constant average degree distribution with high intermediate symbol recovery rates (ISRR) to improve the performance of more important bits (MIB). Asymptotic analysis of the proposed scheme is obtained by deriving unequal density evolution (DE) formulas over the binary erasure channel (BEC). Utilizing LDPC codes and the degree distribution with high ISRR in the proposed scheme, the UEP property is flexible and efficient. Compared with previous duplicate UEP-LT codes, mathematical analysis and simulation results demonstrate that the proposed UEP-LT codes have better performance.