| Project/Area Number |
04650275
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
電子通信系統工学
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| Research Institution | GUNMA UNIVERSITY |
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Principal Investigator |
HORIKOSHI Jun GUNMA UNIVERSITY, ELECTRONIC ENGI., ASSOCIATE PROF., 工学部, 助教授 (10008477)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1992: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | MULTI-LEVEL CPM / MOBILE RADIO / SATELLITE MOBILR MOBILE COMMUNICATIONS / MAXIMUM LILELIHOOD SEQUENCE ESTIMATION / VITERBI ARGOLITHM / ヴィタービ A. / MLSE / 符号化変調 / CPM / 誤り率の改善 / 衛星移動通信 / ヴイタービ復号 / ISIキャンセラー / パーソナル通信 / 移動通信 / レイリーフェージング特性 / 衛星移動変復調 / CPFSK / 多値FSK |
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| Research Abstract |
Available frequency and power are severely limited in the satellite communications. Especially in the satellite mobile radio applications power efficient property of a modulation-demodulation system is inherently necessary condition. Continuous phase modulation (CPM) schemes permit to use highly efficient nonlinear power amplifier but on the other hand it is a well known fact that CPM is severely degraded in the multipath interfering channel. In this research, I propose 4-level CPM named (ss-) QTFSK which offers preferable characteristics for the above noted purpose. Error rate of QTFSK is superior to and shows a comparable or a bit wider spectrum characteristics with the conventional low-deviation 4-level CPFSK.BER of QTFSK can ve attained 10^<-4> in the fast Rayleigh fading environment which has been impossible with the conventional low-deviation 4-level CPFSK.Band-limitation at the transmitting stage yields inter-symbol interferences (ISI) and BER is degraded much in the fast Rayleigh fading channel. Coded modulation based on the block coding and ISI cancel scheme based on the examine likelihood sequence estimation (MLSE) are applied to spectrum shaped (ss) -QTFSK demodulation. Viterbi algorithm (V.A.) and the 1-symbol differential detection (1-DD) are used to MLSE.The systematic block encoding enables one to apply 1-DD because it insures continuity of the signal phase. Coding gain to achieve BER of 10^<-4> is 1.5, 2.5, 3.5 dB in E_b/N_0 for the code lengh 10, 20, 60 bits, respectively. The above coding gain can be obtained only by coding. In the case one introduces ISI canceler via. V.A., coding gain combined with ISI canceler reaches up to 6.5= (1.5+5) dB in E_b/N_0 and BERs obtained under these procedure are almost the same value those of obtained from QDPSK with Nyquist low-pass filter or no ISI condition.
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