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important parameters for keeping satellite links available by altering satellite link design characteristics, and it is necessary to determine the response speed according to the link margin and the attenuation variation rate at rainfall. In accordance with Fig. 21, a rain attenuation compensa-tion of 25 dB must be accomplished against the rain at-tenuation variation rate of about 15 to 20 dB/min. is means that a rain attenuation compensation of 1 dB must be done within about 2 seconds.On the other hand, for preparing for rainfalls around the destination stations, a delay of at least more than one path travelling time on satellite link (about 250 to 300 ms, one way) shall be considered.7Conclusione report presented the experiment results of rain attenuation compensation on the WINDS regenerative link, showing that rain attenuation compensation is eective in the Ka band. In addition, the report presented examples of our measurements conducted on Ka band rain attenuation characteristics and statistical analysis thereof. e basic data for determining the algorithm and the response speed of rain attenuation compensation can be collected success-fully.ReferenceR1“Special Issue on Wideband InterNetworking Engineering Test and Demonstration Satellite (WINDS),” Journal of NICT vol.54 no.4 Dec. 2007.2Takashi Takahashi, Nozomu Nishinaga, Mitsugu Ohkawa, Kazuyoshi Kawasaki, and Toshio Asai, “Rain attenuation characteristics measurement in Ka band,” 2009 IEICE Society Conference.3Toshio Asai, Ryutaro Suzuki, Takashi Takahashi, Mitsugu Ohkawa, and Akira Akaishi, “An Adaptive Satellite Communications System,” 28th International Symposium on Space Technology and Science.4Tomomi Suzuki, Toshio Higuchi, Shinichiro Takayama, Takafumi Horiuchi, Yuji Nakamura, and Masahiro Nakao, “Rain Fade Attenuation Compensation Function of WINDS Communication Systems,” 28th International Symposium on Space Technology and Science.Toshio ASAI Space Communications Laboratory, Wireless Networks Research CenterSatellite communications systemTakashi TAKAHASHI Associate Director, Space Communications Laboratory, Wireless Networks Research CenterSatellite communicationNorihiko KATAYAMA, Dr. Eng.Researcher, Space Communications Laboratory, Wireless Networks Research CenterSatellite communications, Propagation, Network3 Ultra-High-Speed Satellite Communication Technology86　　　Journal of the National Institute of Information and Communications Technology Vol. 64 No. 2 (2017)