作者机构:[1]School of Communication Engineering, Jilin University, Changchun 130012, China, [2]Department of Electrical and Electronic Engineering, Imperial College, London SW72BT, UK, [3]Department of Geophysics, Jilin University, Changchun 130026, China
相关基金:Project supported by the National Natural Science Foundation of China (Grant Nos 40574051 and 40774054).Acknowledgements The authors thank Nicanor A Matias and Lijie Yu for many constructive suggestions.