There are severe Multipath Effects, Doppler Spread and noise in underwater acoustic channels.
水声信道存在多径效应、多卜勒频偏及各种噪声干扰。
Applying Doppler diversity in OFDM system can combat the effect of Doppler spread on system performance.
将多普勒分集技术应用于OFDM系统，可以有效地对抗多普勒扩展对系统性能的影响。
The ways of estimating the frequency offset and Doppler spread width in WCDMA system are studied in this paper.
本文主要研究了WCDMA(宽带码分多址)系统中频偏和最大多普勒频偏的估计方法。
Doppler diversity considers Doppler spread as a way of diversity, and improves the system performance by enhancing the signal energy.
多普勒分集将多普勒扩展作为一种分集方式，通过增强信号能量来改善系统性能。
A detailed analysis is made on the echos Doppler spread and range spread caused by body target spread, and on their influence on ranging.
从理论上分析了由于体目标引起的引信回波信号的多普勒展宽和距离展宽问题，以及它们对近距离扩频测距的影响。
Estimation of the maximum Doppler spread or, equivalently, the speed of the mobile, is of an essential importance for the optimization of receiver algorithms.
估计最大多普勒频移或者是移动台的速度对于优化接收机的性能至关重要。
Extensive simulations show that combining three diversity branches with proper frequency shifts reduces BER by an order when the normalized Doppler spread is larger than 0.3.
大量的仿真结果表明，三个分集结合适当的频率变化，降低了误码率的命令时，归一化多普勒扩展是大于0.3。
In HF channel modeling, doppler spread effects are usually simulated by filtering white Gaussian noise. The signal correlation in time domain deviates far from the theoretical value.
在短波信道建模中，通常采用对高斯白噪声滤波来仿真多普勒扩展效应，这些模型的时域相关值与理论值相差较大。
Aiming at the acquisition problem of direct sequence spread-spectrum (DSSS) signals with large Doppler offset, a new method based on fast Fourier transform (FFT) is proposed.
针对具有大多普勒偏移的直接序列扩频信号捕获问题，提出一种基于快速傅里叶变换(FFT)的多普勒和伪码分别并行搜索的捕获新方法。
The wireless propagation environment is described first: analyzing the small-scaled fading, including amplitude fading, multi-path time delay and Doppler spectrum spread.
在本论文中，首先对移动传播环境作了描述，特别是对小尺度多径传播造成的幅度衰落，多径时延和多普勒频移进行了分析；
The wireless propagation environment is described first: analyzing the small-scaled fading, including amplitude fading, multi-path time delay and Doppler spectrum spread.
在本论文中，首先对移动传播环境作了描述，特别是对小尺度多径传播造成的幅度衰落，多径时延和多普勒频移进行了分析；
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