| Budget Amount *help |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2014: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2013: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2012: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
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| Outline of Final Research Achievements |
Highly efficient 32 amplitude-phase shift keying (32APSK) and 64 quadrature amplitude shift keying (64QAM) modulation satellite broadband communication systems were proposed.
They feature a compact two-beam spatial superposition that improves the usage efficiency of the frequency resources and energy. The 32APSK system incorporates an eight phase-shift keying (8PSK) modulator, a quadrature phase-shift keying (QPSK) modulator, and multiple high power amplifiers (HPAs) that operate in their nonlinear region at a high level of efficiency. Their output signals are spatially combined using a specially tailored antenna array to produce a new 32APSK signal.
An experimental test demonstrated the validity of the spatial superposition. The HPA power consumption was reduced about 50% compared with that of the conventional system. The proposed compact system is feasible and will enable broadband transmission while using the available amount of energy and bandwidth more efficiently.
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