电子学报 ›› 2017, Vol. 45 ›› Issue (8): 2001-2007.DOI: 10.3969/j.issn.0372-2112.2017.08.028

• 学术论文 • 上一篇    下一篇

基于无率纠错码和高阶QAM调制的收端速率自适应方案

雷维嘉, 宋海娜, 陈胜男, 谢显中   

  1. 重庆邮电大学移动通信技术重庆市重点实验室, 重庆 400065
  • 收稿日期:2016-05-23 修回日期:2016-08-19 出版日期:2017-08-25 发布日期:2017-08-25
  • 作者简介:雷维嘉,男,1969年出生,云南元谋人.教授、博士.现主要从事无线通信传输技术的研究.E-mail:leiwj@cqupt.edu.cn;宋海娜,女,1990年出生,湖北襄阳人,硕士研究生.现主要从事调制与编码技术的研究.E-mail:songhn_cqupt@163.com
  • 基金资助:
    国家自然科学基金(No.61471076);重庆市基础与前沿研究计划(No.cstc2015jcyjA40047);长江学者和创新团队发展计划(No.IRT1299);重庆市教委科学技术研究项目(No.KJ1600413)

Rate Adaptive Scheme at Receiver Based on Rateless Error Correcting Codes and High Order QAM

LEI Wei-jia, SONG Hai-na, CHEN Sheng-nan, XIE Xian-zhong   

  1. Chongqing Key Lab oratory of Mobile Communications Technology, Chongqing University of Posts and Tele Communications, Chongqing 400065, China
  • Received:2016-05-23 Revised:2016-08-19 Online:2017-08-25 Published:2017-08-25

摘要: 现有的自适应解调方案中调制阶数最高仅限于16,且方案分析和设计中没有考虑信道编码的译码环节.本文研究适用于高阶QAM的自适应解调算法,并结合无率纠错码提出一种收端速率自适应方案.接收端有多种解调模式,每种解调模式删除一个符号中不同数量的、似然比绝对值最低的几个比特,以提高解调比特的可靠度和平均互信息.从互信息分析的角度,得到在满足要求的译码误码性能时,译码所需要的码字长度的理论结果,进一步给出在译码复杂度约束条件下解调模式的选择方案.以256-QAM调制星座和Raptor码为例对方案进行了仿真,验证了理论分析的正确性和方案的有效性.

关键词: 无率纠错码, 正交幅度调制, 自适应解调, 速率自适应, 互信息

Abstract: The order of the modulation used in existing adaptive demodulation schemes is no higher than 16,and the decoding of channel codes is not taken into consideration in the analysis and design.In this paper,an adaptive demodulation algorithm is studied.It includes multiple demodulation modes and can be applied to higher order quadrature amplitude modulations.A rate adaptive scheme at receiver is proposed which combines this algorithm and rateless error correcting codes.The bits whose absolute values of the log-likelihood ratio are the smallest in one symbol are deleted and the number of deleted bits varies in different demodulation modes,so the reliability and the average mutual information of demodulated bits can be boosted.From the perspective of mutual information analysis,the theoretical results of the required codeword length which meet the requirements of error performance are obtained.Moreover,the selection of the demodulation mode under a decoding complexity constraint is given.A sample scheme employing 256-QAM modulation constellations and Raptor codes is provided,and the simulation results of this sample are consistent well with those of the theoretical analysis,which confirms the effectiveness of the scheme.

Key words: rateless error correcting codes, quadrature amplitude modulation, adaptive demodulate, rate adaptive, mutual information

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