Design of bilayer lengthened LDPC codes over expanded graph for relay channels  

作　　者：刘洋 Li Ying Su Yuping 

机构地区：[1]State Key Laboratory of ISN,Xidian University

出　　处：《High Technology Letters》2015年第4期494-499,共6页高技术通讯（英文版）

基　　金：Supported by the National Basic Research Program of China(No.2012CB316100);the National Natural Science Foundation of China(No.61072064,61201140,61301177)

摘　　要：This paper presents a low complexity optimized algorithm for design of bilayer lengthened LDPC(BL-LDPC) code for decode-and-forward relay system.The design is performed over the expanded graph of the BL-LDPC code,which consists of the original bilayer graph and the extra added relaygenerated parity check bits.To build up our proposed optimized algorithm,we present a modified Gaussian approximation algorithm for the expanded structure of the BL-LDPC code.Then using the proposed optimized algorithm,we find the optimum overall expanded graph of the BL-LDPC code.Simulation results show that the BL-LDPC codes obtained by our proposed optimized algorithm have excellent bit-error-rate performances and small gaps between the convergence thresholds and the theoretical limits when transmitted over the additive white Gaussian noise channels.This paper presents a low complexity optimized algorithm for design of bilayer lengthened LDPC （BL-LDPC） code for decode-and-forward relay system. The design is performed over the expanded graph of the BL-LDPC code, which consists of the original bilayer graph and the extra added relay- generated parity check bits. To build up our proposed optimized algorithm, we present a modified Gaussian approximation algorithm for the expanded structure of the BL-LDPC code. Then using the proposed optimized algorithm, we find the optimum overall expanded graph of the BL-LDPC code. Simulation results show that the BL-LDPC codes obtained by our proposed optimized algorithm have excellent bit-error-rate performances and small gaps between the convergence thresholds and the the- oretical limits when transmitted over the additive white Gaussian noise channels.

关 键 词：bilayer LDPC codes relay channel DECODE-AND-FORWARD Gaussian approxima- tion channel capacity 

分 类 号：TN911.22[电子电信—通信与信息系统] U445.6[电子电信—信息与通信工程]