优化流星暴通信的自适应联合数据与信道估计算法

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本文探讨了在气象突发(Meteor Burst Communications, MBC)通信系统中,由于其特有的不稳定性和多径衰落特性,采用可变速率数据传输以提升系统平均吞吐量的重要性。然而,这种变化带来的挑战是接收端的信道跟踪(Channel Tracking)和均衡(Equalization)问题。传统的最大似然序列检测(Maximum Likelihood Sequence Detection, MLSD)方法,尤其是基于每幸存者处理(Per-Survivor Processing, PSP)原则的联合数据和信道估计,被认为是优化的检测方案,因为它能够准确地估计数据和信道状态。然而,该方法的主要缺点是计算复杂度极高,这与气象通道的快速衰落特性不匹配,使得实时应用变得困难。 MBC环境下的通信需要一种适应性强、性能高效的接收器,以克服这些挑战。为了降低计算负担并适应动态信道条件,研究者们提出了一个适应性接收器的设计,它可能采用了一些降维技术、算法简化或者迭代优化的方法,以减小MLSD在PSP下的复杂度。这种接收器可能包括自适应调制和编码(Adaptive Modulation and Coding, AMC)机制,可以根据信道条件动态调整数据传输速率和编码规则,以保持较高的效率。 此外,性能分析部分可能会涉及对不同接收算法在实际应用中的误码率(Bit Error Rate, BER)、信噪比(Signal-to-Noise Ratio, SNR)依赖性以及系统吞吐量与计算复杂度之间平衡的研究。接收器设计可能还考虑了信号的衰减特性,如指数衰减,以及如何通过有效的前向纠错(Forward Error Correction, FEC)策略来对抗信道失真。 总结来说,这篇文章关注的是如何在气象突发通信中设计一个能有效处理数据和信道估计的适应性接收器,以在保证系统性能的同时,降低计算复杂度。研究者们可能探索了结合PSP的MLSD和其他高效算法的组合,以应对气象通道的快速变化和不稳定,为MBC通信提供了一种实用且性能优越的解决方案。

Please revise the paper:Accurate determination of bathymetric data in the shallow water zone over time and space is of increasing significance for navigation safety, monitoring of sea-level uplift, coastal areas management, and marine transportation. Satellite-derived bathymetry (SDB) is widely accepted as an effective alternative to conventional acoustics measurements over coastal areas with high spatial and temporal resolution combined with extensive repetitive coverage. Numerous empirical SDB approaches in previous works are unsuitable for precision bathymetry mapping in various scenarios, owing to the assumption of homogeneous bottom over the whole region, as well as the limitations of constructing global mapping relationships between water depth and blue-green reflectance takes no account of various confounding factors of radiance attenuation such as turbidity. To address the assumption failure of uniform bottom conditions and imperfect consideration of influence factors on the performance of the SDB model, this work proposes a bottom-type adaptive-based SDB approach (BA-SDB) to obtain accurate depth estimation over different sediments. The bottom type can be adaptively segmented by clustering based on bottom reflectance. For each sediment category, a PSO-LightGBM algorithm for depth derivation considering multiple influencing factors is driven to adaptively select the optimal influence factors and model parameters simultaneously. Water turbidity features beyond the traditional impact factors are incorporated in these regression models. Compared with log-ratio, multi-band and classical machine learning methods, the new approach produced the most accurate results with RMSE value is 0.85 m, in terms of different sediments and water depths combined with in-situ observations of airborne laser bathymetry and multi-beam echo sounder.

2023-02-18 上传