关键词: 通信技术, 网络双层LDPC码, 高斯近似算法, 误码性能

Abstract: Network coding become the research focus of widespread concerning. Because of it can improve the network throughput, has better robustness, and effectively improve the efficiency of forwarding by relay nodes. Therefore, in the relay node, a joint design of network-channel coding can further improve BER performance of the system BER performance. Based on the research of Razaghi, who designed the two kinds of Bilayer-LDPC codes（divided into Expurgated and Lengthened type）, proposes a kind of network-channel coding called NBL-LDPC code（Network Bilayer Lengthened LDPC, referred to as the NBL-LDPC）. Meanwhile, This paper shows the process of encoding and decoding, and for this code, the Gaussian density evolution algorithm has to be improved, so the BER performance can be calculated and simulated. Simulation results show that the proposed coding scheme performs better than the NBE-LDPC code（Network Bilayer Expurgated LDPC, referred to as NBE-LDPC）.

Key words: communications technology, network-bilayer LDPC, Gaussian approximation, Bit Error Rate（BER）