US6138261A
Expired / Lapsed
US
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Concatenated coding system for satellite communications
Assignee: Northrop Grumman Systems Corp
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Filing: 1998-04-29
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Granted: 2000-10-24
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Expires: 2018-04-29
Abstract
Abstract The present invention provides a method for custom coding uplink signals and downlink beams in a satellite communications system. The method includes the step of applying, at a ground station (100), an outer code (102) to an uplink signal to produce an outer coded uplink signal. Next, the ground station (100) applies a selected reduced complexity inner code (104) to the outer coded uplink signal to produce a concatenated coded uplink signal. The ground station (100) transmits the concatenated coded uplink signal to a satellite (110). At the satellite (110), the inner code of the concatenated coded uplink signal is decoded (116) to produce an outer coded satellite data stream. Next, the satellite (110) applies a selected inner code (120) to a portion of the outer coded satellite data stream to produce a concatenated coded satellite data stream. The satellite (110) then transmits the concatenated coded satellite data stream in a downlink beam to a destination ground station (126).
Inventors
- 👤 Donald C. Wilcoxson
- 👤 Chamroeun Kchao
- 👤 Eldad Perahia
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:44
CPC Classifications
H; H03; H03M; H03M13/00; H03M13/03; H03M13/05; H03M13/13; H03M13/15
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
168 words
A method for custom coding uplink signals at a ground station and downlink beams at a satellite, the method comprising the following steps: applying, at an originating ground station, an outer code to a first uplink signal to produce an outer coded uplink signal; applying a reduced complexity inner code to said outer coded uplink signal to produce a concatenated coded uplink signal; transmitting said concatenated coded uplink signal to a satellite; decoding, at said satellite, said reduced complexity inner code on said concatenated coded uplink signal to produce an outer coded satellite data stream; applying at least one selected inner code, at said satellite, to said outer coded satellite data stream, without decoding said outer code at said satellite, to produce a concatenated coded satellite data stream; and transmitting said concatenated coded satellite data stream in a downlink beam to a destination ground station, wherein said first uplink signal remains encoded with said outer code from transmission to the satellite until received by the destination ground station.
Claim 2
Independent Claim
168 words
A method for custom coding uplink signals at a ground station and downlink beams at a satellite, the method comprising the following steps: applying, at an originating ground station, an outer code to a first uplink signal to produce an outer coded uplink signal; applying a reduced complexity inner code to said outer coded uplink signal to produce a concatenated coded uplink signal; transmitting said concatenated coded uplink signal to a satellite; decoding, at said satellite, said reduced complexity inner code on said concatenated coded uplink signal to produce an outer coded satellite data stream; applying at least one selected inner code, at said satellite, to said outer coded satellite data stream, without decoding said outer code at said satellite, to produce a concatenated coded satellite data stream; and transmitting said concatenated coded satellite data stream in a downlink beam to a destination ground station, wherein said first uplink signal remains encoded with said outer code from transmission to the satellite until received by the destination ground station.
Claim 3
Dependent Claim
21 words
The method of claim 1, wherein said step of applying a reduced complexity inner code applies a reduced complexity block code.
Claim 4
Dependent Claim
20 words
The method of claim 1, wherein said step of applying a reduced complexity block code applies a (16,8) block code.
Claim 5
Dependent Claim
20 words
The method of claim 1, wherein said step of applying a reduced complexity block code applies a (8,4) block code.
Claim 6
Dependent Claim
20 words
The method of claim 1, wherein said step of applying a reduced complexity block code applies a (12,8) block code.
Claim 7
Dependent Claim
21 words
The method of claim 1, wherein said step of applying a reduced complexity inner code applies a reduced complexity convolutional code.
Claim 8
Dependent Claim
26 words
The method of claim 6, wherein said step of applying a reduced complexity convolutional code applies a convolutional code with a constraint length between 2-4 inclusive.
Claim 9
Dependent Claim
33 words
The method of claim 1, wherein said step of applying a reduced complexity inner code applies an inner code requiring less than approximately 20% of available processing power at said satellite to decode.
Claim 10
Dependent Claim
33 words
The method of claim 1, wherein said step of applying a selected inner code applies said selected inner code only to one individual data channel located in said outer coded satellite data stream.
Claim 11
Dependent Claim
24 words
The method of claim 1, wherein said step of applying a selected inner code applies said selected inner code to an individual downlink beam.
Claim 12
Dependent Claim
38 words
The method of claim 1, wherein said step of applying a selected inner code adaptively punctures a single inner code in accordance with a BER required for each individual data channel in said outer coded satellite data stream.
Claim 13
Dependent Claim
25 words
The method of claim 1, wherein said step of applying a selected inner code chooses said selected inner code according to a desired downlink BER.
Claim 14
Dependent Claim
24 words
The method of claim 1, wherein said step of applying a selected inner code chooses said selected inner code according to market driven criteria.
Claim 15
Dependent Claim
33 words
The method of claim 1 wherein said step of applying a reduced complexity innercode comprises adapatively selecting inner code based upon at least one of measured downlink signal-to-noise ratio and symbol error rate.
Claim 16
Dependent Claim
19 words
The method of claim 1 comprising interleaving coded Reed Solomon Symbols before applying selected inner code at said satellites.
Claim 17
Dependent Claim
33 words
The method of claim 1, wherein said decoding and applying steps at said satellite further comprise the following steps: conveying said outer coded uplink signal though said satellite without decoding said outer code.
Claim 18
Dependent Claim
44 words
The method of claim 1, further comprising the following steps: measuring at the destination ground station a signal to noise ratio of said downlink beam; and changing a coding rate of said inner code selected by said satellite based on said measured signal-to-noise ratio.
Claim 19
Dependent Claim
41 words
The method of claim 1, further comprising the following step: selecting a coding rate of said inner code applied at said satellite to said satellite data stream independent of a coding rate of said inner code applied to said uplink signal.
Claim 20
Independent Claim
134 words
A method for custom coding downlink beams at a satellite, the method comprising the following steps: receiving, at a satellite, a concatenated coded uplink signal including a reduced complexity inner code having a first inner coding rate; decoding, at said satellite, said reduced complexity inner code on said concatenated coded uplink signal to produce an outer coded satellite data stream; applying at least one selected inner code having a second inner coding rate, at said satellite, to said outer coded satellite data stream to produce a concatenated coded satellite data stream, said first and second inner coding rates being different; and transmitting said concatenated coded satellite data stream in a downlink beam to a destination ground station, wherein said satellite does not decode an outer code applied to the outer coded satellite data stream.
Claim 21
Independent Claim
134 words
A method for custom coding downlink beams at a satellite, the method comprising the following steps: receiving, at a satellite, a concatenated coded uplink signal including a reduced complexity inner code having a first inner coding rate; decoding, at said satellite, said reduced complexity inner code on said concatenated coded uplink signal to produce an outer coded satellite data stream; applying at least one selected inner code having a second inner coding rate, at said satellite, to said outer coded satellite data stream to produce a concatenated coded satellite data stream, said first and second inner coding rates being different; and transmitting said concatenated coded satellite data stream in a downlink beam to a destination ground station, wherein said satellite does not decode an outer code applied to the outer coded satellite data stream.
Claim 22
Dependent Claim
17 words
The method of claim 19, wherein said reduced complexity inner code is a reduced complexity block code.
Claim 23
Dependent Claim
17 words
The method of claim 19, wherein said reduced complexity inner code is a reduced complexity convolutional code.
Claim 24
Dependent Claim
22 words
The method of claim 21, wherein said reduced complexity convolutional code applies is convolutional code with a constraint length between 2-4 inclusive.
Claim 25
Dependent Claim
27 words
The method of claim 19, wherein said step of decoding said reduced complexity inner code requires less than approximately 20% of available processing power at said satellite.
Claim 26
Dependent Claim
34 words
The method of claim 19, wherein said step of applying a selected inner code applies said selected inner code to at least one individual data channel located in said outer coded satellite data stream.
Claim 27
Dependent Claim
24 words
The method of claim 19, wherein said step of applying a selected inner code applies said selected inner code to an individual downlink beam.
Claim 28
Dependent Claim
25 words
The method of claim 19, wherein said step of applying a selected inner code chooses said selected inner code according to a desired downlink BER.
Claim 29
Dependent Claim
38 words
The method of claim 19, wherein said step of applying a selected inner code adaptively punctures a single inner code in accordance with a BER required for each individual data channel in said outer coded satellite data stream.
Claim 30
Dependent Claim
31 words
The method of claim 19 wherein said step of applying a selected inner code adaptively selects an inner code based upon measured downlink signal to noise ratio or symbol error rate.
Claim 31
Dependent Claim
33 words
The method of claim 19 wherein said step of applying a reduced complexity innercode comprises adapatively selecting inner code based upon at least one of measured downlink signal-to-noise ratio and symbol error rate.
Claim 32
Dependent Claim
18 words
The method of claim 19 comprising interleaving coded RS Symbols before applying selected inner code at said satellites.
Claim 33
Dependent Claim
47 words
The method of claim 19, further comprising the following step: conveying outer coded data received in said concatenated coded uplink signal through said satellite to be transmitted in said concatenated coded satellite data stream without decoding on the satellite an outer code of said outer coded data.
Claim 34
Dependent Claim
43 words
The method of claim 19, further comprising the following steps: receiving, via uplink signals to the satellite, adaptation change information indicative of conditions for downlink channels in the downlink beam; and changing said second inner coding rate based on said adaptation change information.
Claim 35
Dependent Claim
32 words
The method of claim 19, further comprising the following step: selecting said second inner coding rate based on channel conditions of the downlink beam and independent of said first inner coding rate.
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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) | 2003-10-24 | 2004-04-24 | 2004-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-10-24 | 2008-04-24 | 2008-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-10-24 | 2012-04-24 | 2012-10-24 | $7700.00 | Window Closed / Lapsed |