中文摘要：

自适应编码调制技术根据信道环境自适应地调整传输参数来提高频谱效率，但是卫星网络中信道的时变特征对该技术的使用造成了一些限制。提出一种基于预测的信噪比估计算法，来应对回路延时带来的不利影响。在预测值基础上，提出一种新的编码调制方案选择算法来选择更强健的编码调制方案。最后，提出一种滑动窗口技术来应对编码调制方案的频繁转换及其引起的系统性能振荡。仿真结果表明，新方案能够使网络资源得到更有效的利用。

英文摘要：

In order to improve the spectrum- effective, the transmission parameters are dynamically adjusted to accommodate the channel conditions in the Adaptive Coding and Modulation （ACM） technique. This improvement is, however, limited when used in satellite environments due to the time -var- ying nature of the channel conditions. In this paper, a predictive - based SNR estimation algorithm is proposed to combat the counterproductive effects caused by the loop delay. Based on the predicted values, a new modulation and code rates（MODCOD） selection algorithm is also proposed to select more robust MODCOD. Finally, a sliding window technique as a method to combat the detrimental effects of the frequent MODCOD switching and the entailed oscillations in the system performance is proposed. Simulation results show that the new scheme has better use of resources.