US5625640A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for and method of broadcast satellite network return-link signal transmission
Assignee: JPMorgan Chase Bank NA
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Filing: 1994-09-16
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Granted: 1997-04-29
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Expires: 2014-09-16
Abstract
Abstract An apparatus and method for return-link transmission in direct broadcast satellite networks having a hub earth station transmitting forward-link signals, and a plurality of remote terminal stations receiving the forward-link signals and transmitting return-link spread-spectrum signals in the same transponder as the forward-link signal so that both are received at the hub station. The apparatus located at the hub station is comprised of a demodulator and a remodulator of the forward-link signals, delay as necessary for composite signals comprising the forward-link signals interfered with the return-link signals and received from a satellite, and a canceler subtracting the remodulated signals from the composite signals. The method includes a sequence of steps for synchronizing the return-link signals with the forward-link signals at the remote terminal stations, synchronizing the return-link signals with the forward-link signals at the satellite, receiving at the hub station from the satellite the composite signal having the forward-link signals interfered with the return-link signals, and canceling at the hub station the forward-link signals in the composite signals prior to spread-spectrum demodulation of the return-link signals.
Inventors
- 👤 Larry C. Palmer
- 👤 Leonard S. Golding
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:38
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/185; H04B7/18523; H04B7/1851; H04B7/18517
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
117 words
An apparatus for return-link signal transmission in direct broadcasting satellite networks having a hub earth station and a plurality of remote terminal earth stations communicating with said hub station via a satellite, said hub station transmitting forward-link signals to said remote terminal stations, and said remote terminal stations transmitting return-link signals to said hub station, comprising: means at said hub station for receiving from said satellite composite signals containing said forward-link signals interfered with said return-link signals and for regenerating said received forward-link signals from said composite signals; and means for subtracting said regenerated forward-link signals from said composite signals, thereby enabling said return-link signals from said remote terminal stations to operate at a higher data rate.
Claim 2
Independent Claim
117 words
An apparatus for return-link signal transmission in direct broadcasting satellite networks having a hub earth station and a plurality of remote terminal earth stations communicating with said hub station via a satellite, said hub station transmitting forward-link signals to said remote terminal stations, and said remote terminal stations transmitting return-link signals to said hub station, comprising: means at said hub station for receiving from said satellite composite signals containing said forward-link signals interfered with said return-link signals and for regenerating said received forward-link signals from said composite signals; and means for subtracting said regenerated forward-link signals from said composite signals, thereby enabling said return-link signals from said remote terminal stations to operate at a higher data rate.
Claim 3
Dependent Claim
30 words
The apparatus for return-link signal transmission recited in claim 1, wherein said regenerating means uses the same phase, clock timing, amplitude level and modulation as those in said forward-link signals.
Claim 4
Independent Claim
155 words
A method of return-link signal transmission in direct broadcasting satellite networks of the type having a hub earth station communicating via a satellite with a plurality of remote terminal earth stations, said hub station transmitting forward-link signals to said satellite, said satellite retransmitting said forward-link signals to said plurality of said remote terminal stations, and said remote terminal stations transmitting return-link signals to said satellite, said satellite retransmitting said return-link signals interfered with said forward-link signals to said hub station, comprising the steps of: synchronizing said return-link signals with said forward-link signals at said remote terminal stations; synchronizing said return-link signals with said forward-link signals at said satellite; receiving composite signal having said forward-link signals interfered with said return-link signals at said hub station; and, canceling at said hub station said received forward-link signals in said composite signals, thereby enabling said return-link signals from said remote terminal stations to operate at a higher data rate.
Claim 5
Independent Claim
155 words
A method of return-link signal transmission in direct broadcasting satellite networks of the type having a hub earth station communicating via a satellite with a plurality of remote terminal earth stations, said hub station transmitting forward-link signals to said satellite, said satellite retransmitting said forward-link signals to said plurality of said remote terminal stations, and said remote terminal stations transmitting return-link signals to said satellite, said satellite retransmitting said return-link signals interfered with said forward-link signals to said hub station, comprising the steps of: synchronizing said return-link signals with said forward-link signals at said remote terminal stations; synchronizing said return-link signals with said forward-link signals at said satellite; receiving composite signal having said forward-link signals interfered with said return-link signals at said hub station; and, canceling at said hub station said received forward-link signals in said composite signals, thereby enabling said return-link signals from said remote terminal stations to operate at a higher data rate.
Claim 6
Dependent Claim
60 words
The method of return-link signal transmission recited in claim 3, wherein said step of canceling said forward-link signals in said composite signals includes: delaying at said hub station of said composite signals received from said satellite; regenerating said received forward-link signals at said hub station; and subtracting said regenerated forward-link signals from said composite signals delayed at said hub station.
Claim 7
Dependent Claim
41 words
The method of return-link signal transmission recited in claim 4, wherein the phase, clock timing, amplitude level, and modulation with which said regenerating of said forward-link signals is accomplished are selected to be the same as those of said forward-link signals.
Claim 8
Dependent Claim
24 words
The method of return-link signal transmission recited in claim 3, wherein said return link signals transmitted from said remote terminal stations are spread-spectrum modulated.
Claim 9
Dependent Claim
21 words
The method of return-link signal transmission recited in claim 6, wherein said spread-spectrum modulated return-link signals are FSK with pseudonoise modulation.
Claim 10
Dependent Claim
21 words
The method of return-link signal transmission recited in claim 6, wherein said spread-spectrum modulated return-link signals are FSK with frequency hopping.
Claim 11
Dependent Claim
45 words
The method of return-link signal transmission recited in claim 3, wherein said step of synchronizing said return-link signals with said forward-link signals at said remote terminal stations includes deriving return-link transmitter pseudo noise chip rates from forward-link QPSK symbols received at said remote terminal stations.
Claim 12
Independent Claim
154 words
A method of return-link signal transmission in direct broadcasting satellite networks of the type having a hub earth station, a satellite, and a plurality of remote terminal earth stations, said hub station transmitting forward-link signals to said plurality of said remote terminal stations via said satellite, and said remote terminal stations transmitting return-link signals via said satellite to said hub station, comprising the steps of: synchronizing said return-link signals with said forward-link signals at said remote terminal stations; synchronizing said return-link signals with said forward-link signals at said satellite; receiving composite signals having said forward-link signals interfered with said return-link signals at said hub station; delaying said composite signals received at said hub station from said satellite; regenerating said received forward-link signals at said hub station; and, subtracting said regenerated forward-link signals from said delayed composite signals, thereby enabling said return-link signals from said remote terminal stations to operate at a higher data rate.
Claim 13
Independent Claim
154 words
A method of return-link signal transmission in direct broadcasting satellite networks of the type having a hub earth station, a satellite, and a plurality of remote terminal earth stations, said hub station transmitting forward-link signals to said plurality of said remote terminal stations via said satellite, and said remote terminal stations transmitting return-link signals via said satellite to said hub station, comprising the steps of: synchronizing said return-link signals with said forward-link signals at said remote terminal stations; synchronizing said return-link signals with said forward-link signals at said satellite; receiving composite signals having said forward-link signals interfered with said return-link signals at said hub station; delaying said composite signals received at said hub station from said satellite; regenerating said received forward-link signals at said hub station; and, subtracting said regenerated forward-link signals from said delayed composite signals, thereby enabling said return-link signals from said remote terminal stations to operate at a higher data rate.
Claim 14
Dependent Claim
42 words
The method of return-link signal transmission recited in claim 10, wherein the phase, clock timing, amplitude level, and modulation with which said regenerating of said received forward-link signals is accomplished are selected to be the same as those of said forward-link signal.
Claim 15
Dependent Claim
23 words
The method of return-link signal transmission recited in claim 10, wherein said return-link signals transmitted from said remote terminal stations are spread-spectrum modulated.
Claim 16
Dependent Claim
21 words
The method of return-link signal transmission recited in claim 12, wherein said spread-spectrum modulated return-link signals are FSK with pseudonoise modulation.
Claim 17
Dependent Claim
21 words
The method of return-link signal transmission recited in claim 10, wherein said spread-spectrum modulated return-link signals are FSK with frequency hopping.
Claim 18
Dependent Claim
45 words
The method of return-link signal transmission recited in claim 10, wherein said step of synchronizing said return-link signals with said forward-link signals at said remote terminal stations includes deriving return-link transmitter pseudo noise chip rates from forward-link QPSK symbols received at said remote terminal stations.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-04-28 | 2000-10-28 | 2001-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-04-28 | 2004-10-28 | 2005-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-04-28 | 2008-10-28 | 2009-04-29 | $7700.00 | Window Closed / Lapsed |