With the rapid growth of satellite traffic,the ability to forecast traffic loads becomes vital for improving data transmission efficiency and resource management in satellite networks.To precisely forecast the short-term traffic loads in satellite networks,a forecasting algorithm based on principal component analysis and a generalized regression neural network (PCA-GRNN) is proposed.The PCA-GRNN algorithm exploits the hidden regularity of satellite networks and fully considers both the temporal and spatial correlations of satellite traffic.Specifically,it selects optimal time series of spatio-temporally correlated historical traffic from satellites as forecasting inputs and applies principal component analysis to reduce the input dimensions while preserving the main features of the data.Then,a generalized regression neural network is utilized to perform the final short-term load forecasting based on the obtained principal components.The PCA-GRNN algorithm is evaluated based on real-world traffic traces,and the results show that the PCA-GRNN method achieves a higher forecasting accuracy,has a shorter training time and is more robust than other state-of-the-art algorithms,even for incomplete traffic datasets.Therefore,the PCA-GRNN algorithm can be regarded as a preferred solution for use in real-time traffic forecasting for realistic satellite networks.