US5066957A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hybrid modulation satellite communication system
Assignee: KDDI Corp
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Filing: 1990-04-20
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Granted: 1991-11-19
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Expires: 2010-04-20
Abstract
Abstract In a satellite communication system including a plural small earth stations (3-8), a relay earth station (2) and a satellite (1), information transmission is undertaken by primary modulation of carrier wave, and transmission of operation status of each small earth station (3-8) is carried out by secondary modulation of said carrier wave. Primary modulation may be BPSK or multiphase PSK (MPSK), and secondary modulation may be PSK, ASK or FSK. Said operation status may be receive signal quality in each small earth station, and the relay earth station (2) may adjust transmit power to said small earth station such that the receive signal quality at small earth stations satisfies desired criteria irrespective of rain attenuation.
Inventors
- 👤 Toshio Mizuno
- 👤 Takuro Muratani
- 👤 Yasuhiko Ito
- 👤 Tatsuo Watanabe
- 👤 Takashi Inoue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:11
CPC Classifications
H; H04; H04L; H04L5/00; H04L5/02; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/185; H04B7/1853; H04B7/18532
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
222 words
Hybrid modulation satellite communication system, comprising: a satellite; relay earth station; a plurality of small earth stations operably coupled with one another through said satellite and said relay earth station, each of said plurality of small earth stations having smaller antenna and weaker transmit power than those of said relay earth station, each of said small earth stations having primary modulator means for receiving and modulating carrier wave based on a first information signal, and for transmitting a primary information signal therefrom, said relay earth station having first demodulator means for receiving and demodulating said primary information signal from said plurality of small earth stations, at least one of said small earth stations having a secondary modulator means for receiving said primary information signal from said primary modulator means and for secondary modulation of said primary information signal, wherein said secondary modulator means further receives a second information signal, wherein said secondary modulator means modulates said primary information signal based on said second information signal, wherein said second information signal includes operation status information, and wherein a secondary modulated signal outputted from said secondary modulator means carries said primary information signal and said secondary information signal, and said relay earth station further having a secondary demodulator means for receiving and demodulating said secondary modulated signal from said plurality of small earth stations.
Claim 2
Dependent Claim
222 words
Hybrid modulation satellite communication system, comprising: a satellite; relay earth station; a plurality of small earth stations operably coupled with one another through said satellite and said relay earth station, each of said plurality of small earth stations having smaller antenna and weaker transmit power than those of said relay earth station, each of said small earth stations having primary modulator means for receiving and modulating carrier wave based on a first information signal, and for transmitting a primary information signal therefrom, said relay earth station having first demodulator means for receiving and demodulating said primary information signal from said plurality of small earth stations, at least one of said small earth stations having a secondary modulator means for receiving said primary information signal from said primary modulator means and for secondary modulation of said primary information signal, wherein said secondary modulator means further receives a second information signal, wherein said secondary modulator means modulates said primary information signal based on said second information signal, wherein said second information signal includes operation status information, and wherein a secondary modulated signal outputted from said secondary modulator means carries said primary information signal and said secondary information signal, and said relay earth station further having a secondary demodulator means for receiving and demodulating said secondary modulated signal from said plurality of small earth stations.
Claim 3
Dependent Claim
25 words
Hybrid modulation satellite communication system according to claim 1, wherein said primary modulator means in each of said small earth stations is a BPSK modulator.
Claim 4
Dependent Claim
26 words
Hybrid modulation satellite communication system according to claim 1, wherein said primary modulator means in each of said small earth stations is a multi-phase PSK modulator.
Claim 5
Dependent Claim
25 words
Hybrid modulation satellite communication system according to claim 1, wherein said secondary modulator means in each of said small earth stations is a PSK modulator.
Claim 6
Dependent Claim
25 words
Hybrid modulation satellite communication system according to claim 1, wherein said secondary modulator means in each of said small earth stations is an ASK modulator.
Claim 7
Dependent Claim
25 words
Hybrid modulation satellite communication system according to claim 1, wherein said secondary modulator means in each of said small earth stations is an FSK modulator.
Claim 8
Dependent Claim
32 words
Hybrid modulation satellite communication system according to claim 1, wherein said second information signal includes operation status of a small earth station including signal quality of a received signal from said satellite.
Claim 9
Dependent Claim
53 words
Hybrid modulation satellite communication system according to claim 7, wherein said relay earth station includes at least an attenuator at an output portion of a modulator means for adjusting transmit power to at least one of said small earth stations according to signal quality forwarded by said small earth station through secondary modulation.
Claim 10
Dependent Claim
18 words
Hybrid modulation satellite communication system according to claim 1, wherein said secondary demodulator means is a phase detector.
Claim 11
Dependent Claim
18 words
Hybrid modulation satellite communication system according to claim 1, wherein said secondary demodulator means is a polarity detector.
Claim 12
Dependent Claim
25 words
Hybrid modulation satellite communication system according to claim 4, wherein said secondary modulator means modulates by a phase shift of one of 45° and -45°.
References Cited (Backward Citations)
US3800245A
Cited
US4228538A
Cited
US4455651A
Cited
US4426711A
Cited
US4418350A
Cited
US4567485A
Cited
US4731866A
Cited
US4910792A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-11-18 | 1995-05-20 | 1995-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-18 | 1999-05-20 | 1999-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-18 | 2003-05-20 | 2003-11-19 | $7700.00 | Window Closed / Lapsed |