DVB-S2X标准在DVB-S2标准的基础上增加多种高阶APSK（amplitude phase shift keying）调制方式，其中16APSK调制增加8+8APSK星座图。主要分析16APSK星座图的特点，并提出一种新的软解调优化算法。该算法与LLR算法和Max-log-MAP算法相比，计算复杂度显著降低。仿真结果表明，优化算法性能损失小，在工程应用中具有较好的实用性。
Multiple high-order APSK modulation schemes are added in the DVB-S2X standard on the basis of the DVB-S2 standard, and an 8+8APSK constellation is added based on the original 16APSK. In this paper, characteristics of a 16-APSK constellation are mainly analyzed, and a new soft demodulation optimization algorithm is proposed. Compared with the LLR algorithm and the Max-log-MAP algorithm, the proposed algorithm has the significantly reduced computational complexity. Simulation results of the three algorithms show that the optimization algorithm is small in performance loss and has good practicability in engineering application.
[1] 卢六翮.DVB-S2X技术解析[J].广播与电视技术,2014,41(7):97-99.
[2] 李远东,凌明伟.第三代DVB卫星电视广播标准DVB-S2X综述[J].电视技术,2014,38(12):28-31,44.
[3] European Telecommunications Standard Institute. Digital video broadcasting (DVB);Second generation framing structure, channel coding and modulation systems for broadcasting, interactive services, news gathering and other broadband satellite applications; Part 1:DVB-S2:EN 302307-1 V1.4.1[S/OL]. (2014-11-01)[2019-12-29]. https://dvb.org/specifications.
[4] European Telecommunications Standard Institute. Digital video broadcasting (DVB);Second generation framing structure, channel coding and modulation systems for broadcasting, interactive services, news gathering and other broadband satellite applications; Part II:S2-Extensions (DVB-S2X):EN 302307-2 V1.2.1[S/OL]. (2014-11-01)[2019-12-29]. https://dvb.org/specifications.
[5] Cho K, Hyun K, Yoon D, et al. An approximated soft decoding algorithm of 16-APSK signal for DVB-S2[C]//2007 Digest of Technical Papers International Conference on Consumer Electronics. Las Vegas, NV, USA:IEEE, 2007:1-2.
[6] Ali P, Hussain F, Jeong J. A new demapping technique for 16-APSK modulation for digital video broadcasting in AWGN channel[C]//2008 Third International Conference on Convergence and Hybrid Information Technology. Busan, Korea (South):IEEE, 2008:9-12.
[7] 段红光,张源.GMR-1卫星通信16-APSK信号软解码算法[J].信息通信,2016(2):22-24.
[8] Yao E X, Yang S, Jiang W. A simplified soft decision demapping algorithm of 16-APSK signals in AWGN channels[C]//2010 Second International Conference on Networks Security, Wireless Communications and Trusted Computing. Wuhan, China:IEEE, 2010:103-106.
[9] Zhang J J, Zhu L D, Guo Y T, et al. A new method of demodulation for 16APSK/32APSK[C]//Proceedings of 2012 5th Global Symposium on Millimeter-Waves. Harbin, China:IEEE, 2012:477-481.
[10] 许大正, 刘爱军. DVB-S2标准中联合LDPC译码的16-APSK星座迭代软判决算法研究[J]. 宇航学报, 2011,32(3):634-639.
[11] Allpress S, Luschi C, Felix S. Exact and approximated expressions of the log-likelihood ratio for 16-QAM signals[C]//Conference Record of the Thirty-Eighth Asilomar Conference on Signals, Systems and Computers, 2004. Pacific Grove, CA,USA:IEEE, 2004:794-798.
[12] Park J W, Ryu C D, Sunwoo M H, et al. Simplified soft-decision demapping algorithm for DVB-S2[C]//2009 International SoC Design Conference (ISOCC). Busan, Korea(South):IEEE, 2009:444-447.
