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1IntroductionKa band rain attenuation compensation experiments were conducted on a regenerative link [1] using the WINDS on-board asynchronous transfer mode baseband switch (ABS), and its validity was conrmed. is paper reports its experimental results. In addition, the rain attenuation characteristics of the TDMA reference burst (RB) signal in the Ka band for the WINDS on-board regenerative link and the rain attenuation characteristics of the WINDS network information signal residual carrier were measured. e correlation between the rain attenuation and the rainfall, and the correlation between the rain attenuation and the change rate in rain attenuation were obtained. ese results were also reported [2].e WINDS regenerative link uses 1.5 M/6 M/24 M/51 M mode TDMA for its uplink, and 155 M mode TDMA for its downlink [1]. Both a xed multi-beam antenna (MBA) and an active-phased array antenna (APAA) were used for the experiments. As the regenerative link privies mutually independent satellite link for downlink and up-link, because the on-board function performs processing of demodulation, exchange, and modulation, the rain at-tenuation compensation experiments were able to be conducted separately for the uplink and the downlink.A 1 m portable earth station, a 1.2 m antenna very-small-aperture terminal (VSAT), and a 2.4 m antenna VSAT were used for MBA experiments, and a 1.8 m an-tenna VSAT, and a 2.4 m antenna VSAT were used for APAA experiments. In addition, the 4.8 m antenna Kashima large earth station was used for both MBA and for APAA experiments. e nal stage power ampliers used in the experiments were respectively a 40W solid state power amplier (SSPA), a 75 W traveling wave tube amplier (TWTA), and a 250 W TWTA.e necessary rain attenuation compensation depends on the antenna size and/or the nal stage output power. In this article, as the standards, the compensation amount of the case of 1.2 m antenna/40 W SSPA VSAT for MBA, and the compensation amount of the case of 2.4 m anten-na/250 W TWTA VSAT for APAA are reported. Note that for a larger size earth station antenna and/or a larger power of transmitter nal stage amplier, the necessary rain attenuation compensation value becomes larger de-pending on the characteristics of the antenna and/or the amplier.Also note: in the MBA experiments reported here, the Kanto Beam is used at an earth station placed in Kashima, so the WINDS satellite performance value under the above geographic conditions was approximately 3.5 dB lower in uplink satellite performance index (G/T) than the beam center value, and approximately 1.5 dB lower in the down-link Eective Isotropic Radiated Power (EIRP). On the other hand, with regard to the experiments using APAA, because the beam is directed to Kashima, there is no such performance grade-down in satellite characteristics.Figure 1 shows the outdoor equipment of the 1.2 m VSAT and the 1 m portable earth station for MBA ex-periments, and the 2.4 m VSAT and the large earth station for APAA experiments.3-2 Experiment Report for Rain Attenuation CompensationToshio ASAI, Takashi TAKAHASHI, and Norihiko KATAYAMASatellite communication in the Ka band (a microwave band of a frequency range from 27 to 40 GHz) is effective in conserving limited satellite frequency resources, and for providing wide-band and high-speed satellite services. However, rain degradation in the Ka band is larger than in the C/Ku-band. A rain degradation compensation technique would be effective to increase satellite link availability under rain conditions. This report provides the effectiveness of rain degradation compensation by an experiment using the WINDS satellite.In addition, the correlation between rain attenuation and rain rate, rain attenuation and rain attenuation rate are provided coming from the Ka band rain attenuation measurements.773 Ultra-High-Speed Satellite Communication Technology