Accurate channel modeling is the foundation of communication system design. However, the traditional measurement-based modeling approach has increasing challenges for the scenarios with insufficient measurement data. To obtain enough data for channel modeling, the Artificial Neural Network (ANN) is used in this paper to predict channel data. The high mobility railway channel is considered, which is a typical scenario where it is challenging to obtain enough data for modeling within a short sampling interval. Three types of ANNs, the Back Propagation Network, Radial Basis Function Neural Network and Extreme Learning Machine, are considered to predict channel path loss and shadow fading. The Root-Mean-Square error is used to evaluate prediction accuracy. The factors that may influence prediction accuracy are compared and discussed, including the type of network, number of neurons and proportion of training data. It is found that a larger number of neurons can significantly reduce prediction error, whereas the influence of proportion of training data is relatively small. The results can be used to improve modeling accuracy of path loss and shadow fading when measurement data is reduced.
翻译:精确的信道建模是通信系统设计的基础。然而,传统的基于测量的模型方法对测量数据不足的假设情况提出了越来越多的挑战。为了获得足够的数据进行频道建模,本文件使用了人工神经网络(ANN)来预测频道数据。考虑的是高流动性铁路频道,这是一个典型的情景,在这种情景下,很难获得足够的数据在较短的取样间隔内进行建模。三种类型的ANN,即Back Propagation网络、Radial Basic 函数神经网络和极端学习机器,被认为是用来预测通道路径丢失和阴影消失。根-MEan-方错误用来评价预测准确性。可以比较和讨论可能影响预测准确性的因素,包括网络类型、神经元数量和培训数据的比例。发现,大量神经元可以大大减少预测错误,而培训数据的比例影响则相对较小。结果可用于改进测量数据减少时路径丢失和阴影淡化的建模精度。