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to strengthen robustness against noise. In the case of wideband modems, the modulation scheme for the phase reference burst signal was π/2 shi BPSK. e frame composition of the phase reference burst signal is shown in Fig. 8.We assigned the phase reference burst signal to each 187-symbol data length, and made it so that symbol length “P” could be assigned through the range of 1–16.3.3Results of transmission performance by strengthening synchronizatione results of the characteristics of “P” symbol length of the phase reference burst signal versus the required C/N (@1 E-6) at the IF and WINDS satellite loopback are shown in Fig. 9. e modulation scheme was set to 8-PSK and LDPC inner code rates were set to 1/2, 3/5, and 2/3. e other transmission parameters were as listed in Table 3, and the roll-o factor was xed at 0.1. Transmission ex-periments were conducted by using the same uplink earth station (transmitting antenna with a diameter of 4.8 m) listed in Fig. 7. e noise was added to the downlink signal so that C/N value was set. As a result, the required C/N for a code rate of either 1/2 or 3/5 was improved along with an increase in “P” symbol length, but that for a code rate of 2/3 was barely improved.C/N versus BER characteristics for 8-PSK with code rates of 1/2, 3/4, and 9/10 at the IF and WINDS loopback are shown in Fig. 10. From the results of Fig. 9, P=16 was only set during 8-PSK (1/2), and all others were xed at P=0. As a result, the degradation of the required C/N was around 0.3–0.4 dB by going through the WINDS satellite.4ConclusionWe hypothesized the 12 and 21 GHz band satellite broadcastings and carried out verication for each of their functions and performances with an actual satellite trans-mission channel of WINDS. e experimental results premised on the 12 GHz band satellite broadcasting con-tributed to the realization of a 4K/8K test satellite broad-casting (beginning August 2016) and of practical satellite FiF8　 Phase reference burst signal frame compositionP symbolsπ/2shiftBPSK187 symbolsQ/8PSK22440 + 120×P Symbols (QPSK) or 14960 + P ×80 Symbols (8PSK)No.80 or No.120No.2DataP symbolsπ/2shiftBPSK187 symbolsQ/8PSKNo.1DataHeader26 symbolsπ/2shiftBPSKP symbolsπ/2shiftBPSKPhase reference burst signal (symbol length：P=1・・・16) FiF9　Characteristics of symbol length vs. necessary C/NFiF10　C/N vs. BER characteristics in WINDS satellite loopback55.566.577.580246810121416Length of PRBS : PRequired C/N [dB]8PSK(1/2) satellite8PSK(1/2) IF8PSK(3/5) IF8PSK(3/5) satellite8PSK(2/3) IF8PSK(2/3) satelliteSymbol length：PRequired C/N [dB]101.E-091.E-081.E-071.E-061.E-051.E-041.E-031.E-021.E-0134567891011121314C/N [dB]BER1/23/49/10IFSatelliteIFSatelliteSatelliteAWGN SimIFAWGN SimAWGN SimCoderate：1/2 (P=16)3/4 (P=0)9/10 (P=0)Theoretical Calculation計算理論値計算理論値Theoretical CalculationTheoretical CalculationTabT3　Transmission parameters for wideband modemModulation schemeQPSK, 8-PSKSymbol rate250 MbaudRoll-off factor0.1, 0.2, 0.35, 0.5Information bit rateQPSK (3/4): 370 Mbps,8-PSK (2/3): 500 MbpsForward error correctionLDPC (internal code) + BCH (external code)LDPC inner code rate1/2, 3/5, 2/3, 4/5, 5/6, 7/8, 9/101233-6 SHV Transmission Experiments