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Kashima Space Technology Center (Kashima City, Ibaraki Pref.) is the location of LET and Keihanna Plaza are con-nected by broadband network for research and develop-ment of JGN2 plus. Slot allocation of TDMA transmission from Kanto (LET) is 1 slot column (about 30 Mbit/s) and that from Kinki (SDR-VSAT1) is 13 slot column (about 400 Mbit/s). We conrmed that packet error was 0% for the case from SDR-VSAT1 to LET at 400 Mbit/s, and from LET to SDR-VSAT1 at 30 Mbit/s. e video taken by a three-dimensional (3D) 4K–HDTV camera was compressed to 200–300 Mbps via 8 channels of a multi-channel picture transmission system. en 3D, 4K HDTV video was re-ceived with LET via a satellite line of 400 Mbit/s. From LET to the event site, the data was transmitted via a ground network system (JGN2 plus/VLAN), that led to a success-ful and high-quality display.4Summarye development of WINDS was completed and it was launched successfully. Today, many kinds of experiments are performed. NICT has developed a dual high rate burst modem of 622/1,244 Mbit/s that is installed in SDR-VSAT1, 2 and LET for high-speed network experiments.We conrmed that the BER characteristic in a bent-pipe transponder was less than 10-10 for the case of Eb/No of 10dB at 622 Mbit/s. Also, we conrmed that the BER characteristic was less than 10-10 for the case of Eb/No of 13dB at 1,244 Mbit/s. As a result, compared with the BER characteristic at IF, there was deterioration of about 2dB at 622 Mbit/s, and about 4 dB at 1,244 Mbit/s. Also, a data transmission experiment using Ka band 1 carrier at 1,244 Mbit/s was successful (the fastest in the world, as was 2010). e 622/1,244 Mbit/sTDMA transmission in the WINDS vent pipe mode succeeded. Trac burst was suc-cessfully sent to the TDMA slot using the WRB frame pulse synchronized with the JRB frame pulse. Bidirectional transmission at both 300 Mbit/s and 589 Mbit/s was con-rmed in the experiment of Iperf-UDP. Also, we conrmed 622 Mbit/s for full slot unidirectional transmission. Bandwidth of 200–300 Mbit/s for 622/1,244 Mbit/s was achieved using hybla TCP. Also, as an application test, a 3D 4K HDTV video transmission experiment was per-formed and succeeded using the TDMA transmission mode in the 622 Mbit/s 1 wave TDMA mode between the Kanto-Kinki beam.TabT9　hybla TCP throughputtime(sec)Window size(Mbyte)Bandwidth(Mbps)1804501803220626421024418064213226176274FiF16　3D 4K-HDTV application experiment1093-4 622/1,244 Mbit/s Dual Rate High-Speed Burst Modem TDMA Satellite Communication Experiments