| 摘要: |
| 基于自适应编码调制的遥感数据传输方案实现了传输速率阶梯式换挡，但未能充分利用链路余量。为进一步提高遥感卫星数据传输过程中的频谱效率，提出了基于无速率码的遥感数据自适应传输技术。将无速率码与QPSK、8PSK、16QAM、64QAM调制方式结合，通过设定译码成功概率阈值得到离散信噪比下的最佳译码开销和最佳码率值。采用多项式拟合求得卫星过境期间码率值的变化情况，进而得到有效数据率变化曲线，实现了遥感卫星过境时段内有效数据率随仰角的无缝切换。通过求解有效数据率曲线的积分值，得到了采用联合译码算法的Raptor码在4种方案下的传输数据量。分析结果表明，与第二代数字卫星电视广播标准（DVB-S2）中的自适应编码调制方案相比，所提出的传输方案使传输数据量提高了10.29%~27.65%，且在信噪比低至-5 dB的情况下也可以进行数据自适应传输。 |
| 关键词: 遥感数据传输 无速率码 速率自适应 编码调制 |
| DOI： |
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| 基金项目:国家高技术研究发展计划（863计划）项目（2015AA7026085） |
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| Adaptive transmission technology of remote sensing data based on rateless codes |
| SONG Xin,LIAO Yurong,DING Dan,YANG Xinyan,ZENG Jianghui |
| (Department of Graduate Management,
Aerospace Engineering University,Beijing 101416,China;Department of Electronic and Optical Engineering,
Aerospace Engineering University,Beijing 101416,China) |
| Abstract: |
| The remote sensing data transmission scheme based on Adaptive Coding and Modulation(ACM) has realized step change of transmission rate,but ACM still fails to make full use of link margin.In order to further improve the spectrum efficiency of the remote sensing satellite data transmission process,adaptive transmission technology of remote sensing data based on rateless codes is proposed.The rateless codes are combined with QPSK,8PSK,16QAM and 64QAM modulation mode,and the optimal decoding cost and the best code rate under discrete signal-to-noise ratio(SNR) are obtained by setting decoding success probability threshold.Polynomial fitting is applied to get the change of code rate during satellite transit process,and then the effective data transmission rate curve is obtained which realizes seamless change with elevation during satellite transit process.By solving integration number of effective data transmission rate,the data amount of the 4 schemes is obtained in which the Raptor code uses the joint decoding algorithm.The results indicate that the proposed transmission schemes can improve the data amount by 10.29%~27.65% compared with ACM scheme in DVB-S2,and they can achieve data adaptive transmission even the SNR is as low as -5 dB. |
| Key words: remote sensing data transmission rateless code rate adaptive coded modulation |
