Department of Engineering Science and Ocean Engineering, National Taiwan University, Taipei, Taiwan.
J Acoust Soc Am. 2013 Apr;133(4):2180-90. doi: 10.1121/1.4792151.
Uncorrelated scattering (US), which assumes that multipath arrivals undergo uncorrelated scattering and are thus uncorrelated, has been the standard model for digital communications including underwater acoustic communications. This paper examines the cross-correlation of multipath arrivals based on at-sea data with different temporal coherence time, assuming quasi-stationary statistics. It is found that multipath arrivals are highly cross-correlated when the channel is temporally coherent, and are uncorrelated when the channel is temporally incoherent. A theoretical model based on the path phase rates and relative-phase fluctuations is used to explain experimentally observed phenomena, assuming the path amplitudes vary slowly compared with the phases. The implications of correlated scattering for underwater acoustic communication channel tracking are discussed.
非相关散射（US）假设多径到达经历非相关散射，因此是不相关的，它一直是数字通信（包括水声通信）的标准模型。本文基于不同时间相干时间的海上数据，在准静态统计假设下，研究了多径到达的互相关。研究发现，当信道具有时间相干性时，多径到达高度相关，而当信道具有时间非相干性时，多径到达不相关。本文使用基于路径相位速率和相对相位波动的理论模型来解释实验观测到的现象，假设路径幅度与相位相比变化缓慢。讨论了相关散射对水声通信信道跟踪的影响。
