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3.2Transmission experiment at 1,244 Mbit/s(1) Kanto Beam 1,244 Mbit/s 1 wave transmissione characteristic of bit error rate (BER) in 1,244 Mbit/s 1 wave continuous transmission is shown in Fig. 13.It is the property of LET-LET and of SDR-VSAT1-SDR-VSAT1 in the route of WINDS-BPF-W1. e BER achieved 10-10 when Eb/No is over 13 dB. e characteristic of turn-ing of modem IF at BER of 10-10 shows deterioration of 4 dB. Because the transmission at 1,244 Mbit/s has broad band-width of 824 Msymbol/s, the signal quality degrades due to variation in frequency properties and receiving signal levels of satellite the line and earth terminals. At the time of experiment (2010), the data transmission with one car-rier at 1,244 Mbit/s was the fastest in the world in RF satellite transmission.(2) Kanto Beam transmission experiment at 1,244 Mbit/s TDMAAs shown in Fig. 14, a modem was added to the con-guration shown in Fig. 1 to perform an experiment at 1,244 Mbit/sTDMA. Both modem1 and modem2 were connected with SDR-VSAT1 and they operated simultane-ously. e slot allocation of TDMA for the iperf experiment is shown in Fig. 15. Slot1 is the route from modem2 to modem1, and slot2 is the route from modem3 to modem2. e results of the iperf experiment at UDP are summarized in Table 8. As shown in the results, although the volume of the transmitted data rate was less than 1,244 Mbit/s due to the overhead of iperf, it was conrmed that data was transmitted without packet error at bidirectional 1,178 (one way 589 ×2) Mbit/s. In Table 9, the result of the iperf ex-periment for TCP is for the case of packet error rate of UDP at less than 0.01%. e bandwidth was improved from 50 Mbit/s to 200–300 Mbit/s when the window size was expanded from 4 MB to 64 MHz by hybla. us, the bandwidth may be improved by expanding the window size.3.33D, 4K HDTV application transmission experiment [12] [13]e transmission experiment of a three-dimensional (3D) 4K HDTV video between Kanto-Kinki Beam by 1 wave TDMA transmission mode at 622 Mbit/s was per-formed. e conguration of the demonstration performed at the NICT Keihanna Fair held in November 2010 is shown in Fig. 16. It was performed as a memorial event of the 1,300th year anniversary of the establishment of the old capital Nara Heijo-kyo held in Nara Prefecture. NICT FiF15　TDMA slot allocation for 1244 Mbit/s transmission test01234567891011121314151617181901212121212121212121ＲＢWRB121212121212121212212121212121212121231212121212121212124121212121212121212512121212121212121261212121212121212127121212121212121212812121212121212121291212121212121212121012121212121212121211121212121212121212121212121212121212121312121212121212121214121212121212121212151212121212121212121:SDR-VSAT1（MODEM2)>SDR-VSAT1（MODEM3) 2:SDR-VSAT1（MODEM3)>SDR-VSAT1（MODEM2)FiF14Configuration of 1244 Mbit/s TDMA communication experimentMODEM-1(Master)MODEM-2(Slave)PC-1WRBData1178Mbit/sJRBReference Station(JAXA)LETSDR-VSAT1JRBReceiverSatellite Position,Slot Assign Info., etc.Synchronous SignalMODEM-3(Slave)PC-21178Mbit/sWINDSFiF13　BER result for 1244 Mbit/s transmission test1.0E-101.0E-091.0E-081.0E-071.0E-061.0E-051.0E-041.0E-031.0E-021.0E-011.0E+0056789101112131415BEREb/No (dB)LETSDR-VSAT1IF Loopback>10-10SDR-VSAT1⇔SDR-VSAT1Eb/No589 MbpsRemarksModem-2⇒Modem-313dB-14dBLoss 0%9 slots in frameModem-3⇒Modem-213dB-14dBLoss 0%9 slots in frameTabT8　iperf test UDP3 Ultra-High-Speed Satellite Communication Technology108　　　Journal of the National Institute of Information and Communications Technology Vol. 64 No. 2 (2017)