Source: http://www.google.com/patents/US7426243?dq=6,993,661
Timestamp: 2014-10-22 07:21:57
Document Index: 475637659

Matched Legal Cases: ['Application No. 2502924', 'Application No. 2491259', 'Application No. 03757359', 'Application No. 03794510', 'Application No. 04256234', 'Application No. 03742400', 'Application No. 03777694', 'Application No. 03742393', 'Application No. 03774848', 'Application No. 03777627', 'Application No. 07075745', 'Application No. 02728894', 'Application No. 2004', 'art 1', 'Application No. 092129629']

Patent US7426243 - Preprocessing signal layers in a layered modulation digital signal system to ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsSystems and methods for receiving non-coherent layered modulation signals are presented. An exemplary apparatus comprises a tuner for receiving a layered signal and producing a layered in-phase signal and a layered quadrature signal therefrom, an analog-to-digital converter for digitizing the layered...http://www.google.com/patents/US7426243?utm_source=gb-gplus-sharePatent US7426243 - Preprocessing signal layers in a layered modulation digital signal system to use legacy receiversAdvanced Patent SearchPublication numberUS7426243 B2Publication typeGrantApplication numberUS 11/619,173Publication dateSep 16, 2008Filing dateJan 2, 2007Priority dateApr 27, 2001Fee statusPaidAlso published asUS7245671, US20070147547Publication number11619173, 619173, US 7426243 B2, US 7426243B2, US-B2-7426243, US7426243 B2, US7426243B2InventorsErnest C. Chen, Tiffany S. Furuya, Philip R. Hilmes, Joseph SantoruOriginal AssigneeThe Directv Group, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (101), Non-Patent Citations (66), Referenced by (2), Classifications (12), Legal Events (1) External Links: USPTO, USPTO Assignment, EspacenetPreprocessing signal layers in a layered modulation digital signal system to use legacy receiversUS 7426243 B2Abstract Systems and methods for receiving non-coherent layered modulation signals are presented. An exemplary apparatus comprises a tuner for receiving a layered signal and producing a layered in-phase signal and a layered quadrature signal therefrom, an analog-to-digital converter for digitizing the layered in-phase signal and the layered quadrature signal, a processor for decoding the layered in-phase signal and the layered quadrature signal to produce a single layer in-phase signal and a single layer quadrature signal, a digital-to-analog encoder for converting the single layer in-phase signal and the single layer quadrature signal to a single layer in-phase analog signal and a single layer quadrature analog signal and a modulator for modulating the single layer in-phase analog signal and the single layer quadrature analog signal to produce a single layer signal.
1. An apparatus for receiving a non-coherent layered modulation signal comprising the sum of a first layer signal and a second layer signal, comprising:
a tuner for receiving the non-coherent layered signal and producing a layered in-phase signal and a layered quadrature signal therefrom;
an analog-to-digital converter for digitizing the layered in-phase signal and the layered quadrature signal;
a digital processor for processing the digitized layered in-phase signal and the digitized layered quadrature signal to produce a lower layer in-phase signal, a lower layer quadrature signal, an upper layer in-phase signal and an upper layer quadrature signal, the processor comprising a subtractor configured to subtract an ideal upper layer in-phase signal from the digitized layered in-phase signal to produce the lower layer in-phase signal and to subtract an ideal upper layer quadrature signal from the digitized layered quadrature signal to produce the lower layer quadrature signal;
a digital-to-analog encoder for converting the lower layer in-phase signal and the lower layer quadrature signal to a lower layer in-phase analog signal and a lower layer quadrature analog signal; and
a modulator for modulating the lower layer in-phase analog signal and the lower layer quadrature analog signal to produce a lower layer signal.
2. The apparatus of claim 1, wherein the non-coherent layered signal is compatible with a legacy receiver such that at least one signal layer is decodeable directly from the layered signal with the legacy receiver.
3. The apparatus of claim 1, wherein the processor comprises a logic circuit.
4. The apparatus of claim 1, wherein processing by the processor comprises match filtering the digitized layered in-phase signal and the digitized layered quadrature signal.
5. The apparatus of claim 1, wherein the digitized layered in-phase signal and the digitized layered quadrature signal are delayed to synchronize the subtraction.
6. The apparatus of claim 1, wherein the processor applies a signal map to the ideal upper layer in-phase signal and the ideal upper layer quadrature signal, the signal map accounting for transmission distortions of the non-coherent layered signal.
7. The apparatus of claim 1, wherein the processor amplitude and phase matches the ideal upper layer in-phase signal and the ideal upper layer quadrature signal with the digitized layered in-phase signal and the digitized layered quadrature signal, respectively.
8. A digital processor for decoding a non-coherent layered signal to produce a single layer signal, comprising:
a demodulator and decoder for decoding an upper layer signal from the non-coherent
layered signal;
an encoder for generating an ideal upper layer signal from the decoded upper layer signal;
a signal processor for modifying the ideal upper layer signal to characterize transmission and processing effects; and
a subtractor for subtracting the modified ideal upper layer signal from the layered signal to produce the single layer signal.
9. The digital processor of claim 8, further comprising a delay function correlated to an output of the signal processor to appropriately delay the layered signal to synchronize amplitude and phase matching of the modified ideal upper layer signal and the layered signal.
10. The digital processor of claim 8, further comprising a delay function correlated to an output of the signal processor to appropriately delay the layered signal to synchronize subtraction of the modified ideal upper layer signal and the layered signal.
11. The digital processor of claim 8, wherein the signal processor amplitude and phase matches the ideal upper layer signal with the layered signal.
12. The digital processor of claim 9, wherein the signal processor applies a signal map to the ideal upper layer signal.
13. The digital processor of claim 9, wherein the signal processor performs finite impulse response matched filtering on the ideal upper layer signal.
14. A method of receiving a non-coherent layered modulation signal, comprising the steps of:
receiving the non-coherent layered signal and producing a layered in-phase signal and a layered quadrature signal therefrom;
digitizing the layered in-phase signal and the layered quadrature signal;
processing the digitized layered in-phase signal and the digitized layered quadrature signal to produce a lower layer in-phase signal, a lower layer quadrature signal, an upper layer in-phase signal, and an upper layer quadrature signal;
subtracting an ideal upper layer in-phase signal from the digitized layered in-phase signal to produce the lower layer in-phase signal and subtracting an ideal upper layer quadrature signal from the digitized layered quadrature signal to produce the lower layer quadrature signal;
converting the lower layer in-phase signal and the lower layer quadrature signal to a lower layer in-phase analog signal and a lower layer quadrature analog signal; and
modulating the lower layer in-phase analog signal and the lower layer quadrature analog signal to produce a single layer signal.
15. The method of claim 14, wherein the non-coherent layered signal is compatible with a legacy receiver such that at least one signal layer is decodeable directly from the layered signal with the legacy receiver.
16. The method of claim 14, wherein the lower layer signal from the modulator is decodeable with a legacy receiver.
17. The method of claim 14, wherein the steps of processing and subtracting are performed by a logic circuit.
18. The method of claim 14, wherein the step of processing comprises match filtering the digitized layered in-phase signal and the digitized layered quadrature signal.
19. The method of claim 15, wherein the step of processing further comprises delaying the digitized layered in-phase signal and the digitized layered quadrature signal to synchronize the subtraction.
20. The method of claim 15, further comprising the step of applying a signal map to the ideal upper layer in-phase signal and the ideal upper layer quadrature signal, the signal map accounting for transmission distortions of the non-coherent layered signal.
21. The method of claim 15, further comprising the step of amplitude and phase matching the ideal upper layer in-phase signal and the ideal upper layer quadrature signal with the digitized layered in-phase signal and the digitized layered quadrature signal, respectively.
CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 10/068,039, filed Feb. 5, 2002 now U.S. Pat. No. 7,245,671 which is a continuation-in-part application claiming priority under 35 U.S.C. �120 from U.S. patent application Ser. No. 09/844,401, filed Apr. 27, 2001, and entitled �LAYERED MODULATION FOR DIGITAL SIGNALS�, now issued as U.S. Pat. No. 7,209,524 and from U.S. patent application Ser. No. 10/068,047, filed Feb. 5, 2002, and entitled �DUAL LAYER SIGNAL PROCESSING IN A LAYERED MODULATION DIGITAL SIGNAL SYSTEM�, now issued as U.S. Pat. No. 7,173,981, all of which applications are hereby incorporated by reference herein.
Application Ser. No. 11/653,517, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Jan. 16, 2007, by Ernest C. Chen, which is a continuation of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/165,710, entitled �SATELLITE TWTA ON-LINE NON-LINEARITY MEASUREMENT,� filed on Jun. 7, 2002, by Ernest C. Chen, which is a continuation-in-part of Application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/236,414, entitled �SIGNAL, INTERFERENCE AND NOISE POWER MEASUREMENT,� filed on Sep. 6, 2002, by Ernest C. Chen and Chinh Tran, which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/693,135, entitled �LAYERED MODULATION FOR ATSC APPLICATIONS,� filed on Oct. 24, 2003, by Ernest C. Chen, which claims benefit to Provisional Patent Application 60/421,327, filed Oct. 25, 2002 and which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/913,927, entitled �CARRIER TO NOISE RATIO ESTIMATIONS FROM A RECEIVED SIGNAL,� filed on Aug. 5, 2004, by Ernest C. Chen which is a continuation in part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/693,421, entitled �FAST ACQUISITION OF TIMING AND CARRIER FREQUENCY FROM RECEIVED SIGNAL,� filed on Oct. 24, 2003, by Ernest C. Chen, now issued as U.S. Pat. No. 7,151,807, which claims priority to Provisional Patent Application Ser. No. 60/421,292, filed Oct. 25, 2002, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 11/603,776, entitled �DUAL LAYER SIGNAL PROCESSING IN A LAYERED MODULATION DIGITAL SIGNAL SYSTEM,� filed on Nov. 22, 2006, by Ernest C. Chen, Tiffany S. Furuya, Philip R. Hilmes, and Joseph Santoru, which is a continuation of application Ser. No. 10/068,047, entitled �DUAL LAYER SIGNAL PROCESSING IN A LAYERED MODULATION DIGITAL SIGNAL SYSTEM,� filed on Feb. 5, 2002, by Ernest C. Chen, Tiffany S. Furuya, Philip R. Hilmes, and Joseph Santoru, now issued as U.S. Pat. No. 7,173,981, which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/69 1,032, entitled �UNBLIND EQUALIZER ARCHITECTURE FOR DIGITAL COMMUNICATION SYSTEMS,� filed on Oct. 22, 2003, by Weizheng W. Wang, Tung-Sheng Lin, Ernest C. Chen, and William C. Lindsey, which claims priority to Provisional Patent Application Ser. No. 60/421,329, filed Oct. 25, 2002, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/962,346, entitled �COHERENT AVERAGING FOR MEASURING TRAVELING WAVE TUBE AMPLIFIER NONLINEARITY,� filed on Oct. 8, 2004, by Ernest C. Chen, which claims priority to Provisional Patent Application Ser. No. 60/510,368, filed Oct. 10, 2003, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 11/655,001, entitled �AN OPTIMIZATION TECHNIQUE FOR LAYERED MODULATION,� filed on Jan. 18,2007, by Weizheng W. Wang, Guancai Zhou, Tung-Sheng Lin, Ernest C. Chen, Joseph Santoru, and William Lindsey, which claims priority to Provisional Patent Application 60/421,293, filed Oct. 25, 2002, and which is a continuation of application Ser. No. 10/693,140, entitled �OPTIMIZATION TECHNIQUE FOR LAYERED MODULATION,� filed on Oct. 24, 2003, by Weizheng W. Wang, Guancai Zhou, Tung-Sheng Lin, Ernest C. Chen, Joseph Santoru, and William Lindsey, now issued as U.S. Pat. No. 7,184,489, which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 11/656,662, entitled �EQUALIZERS FOR LAYERED MODULATION AND OTHER SIGNALS,� filed on Jan. 22, 2007, by Ernest C. Chen, Tung-Sheng Lin, Weizheng W. Wang, and William C. Lindsey, which claims priority to Provisional Patent Application 60/421,241, filed Oct. 25, 2002, and which is a continuation of application Ser. No. 10/691,133, entitled �EQUALIZERS FOR LAYERED MODULATED AND OTHER SIGNALS,� filed on Oct. 22, 2003, by Ernest C. Chen, Tung-Sheng Lin, Weizheng W. Wang, and William C. Lindsey, now issued as U.S. Pat. No. 7,184,473, which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/961,579, entitled �EQUALIZATION FOR TWTA NONLINEARITY MEASUREMENT� filed on Oct. 8, 2004, by Ernest C. Chen, which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/532,632, entitled �LOWER COMPLEXITY LAYERED MODULATION SIGNAL PROCESSOR,� filed on Apr. 25, 2005, by Ernest C. Chen, Weizheng W. Wang, Tung-Sheng Lin, Guangcai Zhou, and Joseph Santoru, which is a National Stage Application of PCT U503/32264, filed Oct. 10, 2003, which claims priority to Provisional Patent Application 60/421,331, entitled �LOWER COMPLEXITY LAYERED MODULATION SIGNAL PROCESSOR,� filed Oct. 25, 2002, by Ernest C. Chen, Weizheng W. Wang, Tung-Sheng Lin, Guangcai Zhou, and Joseph Santoru, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/532,631, entitled �FEEDER LINK CONFIGURATIONS TO SUPPORT LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 25, 2005, by Paul R. Anderson, Joseph Santoru and Ernest C. Chen, which is a National Phase Application of PCT US03/33255, filed Oct. 20, 2003, which claims priority to Provisional Patent Application 60/421,328, entitled �FEEDER LINK CONFIGURATIONS TO SUPPORT LAYERED MODULATION FOR DIGITAL SIGNALS,� filed Oct. 25, 2002, by Paul R. Anderson, Joseph Santoru and Ernest C. Chen, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/532,619, entitled �MAXIMIZING POWER AND SPECTRAL EFFICIENCIES FOR LAYERED AND CONVENTIONAL MODULATIONS,� filed on Apr. 25, 2005, by Ernest C. Chen, which is a National Phase Application of PCT Application US03/32800, filed Oct. 16, 2003, which claims priority to Provisional Patent Application 60/421,288, entitled �MAXIMIZING POWER AND SPECTRAL EFFICIENCIES FOR LAYERED AND CONVENTIONAL MODULATION,� filed Oct. 25, 2002, by Ernest C. Chen and which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524,
Application Ser. No. 10/532,524, entitled �AMPLITUDE AND PHASE MATCHING FOR LAYERED MODULATION RECEPTION,� filed on Apr. 25, 2005, by Ernest C. Chen, Jeng-Hong Chen, Kenneth Shum, and Joungheon Oh, which is a National Phase Application of PCT Application US03/31199, filed Oct. 3, 2003, which claims priority to Provisional Patent Application 60/421,332, entitled �AMPLITUDE AND PHASE MATCHING FOR LAYERED MODULATION RECEPTION,� filed Oct. 25, 2002, by Ernest C. Chen, Jeng-Hong Chen, Kenneth Shum, and Joungheon Oh, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524, and also claims priority to;
Application Ser. No. 10/532,582, entitled �METHOD AND APPARATUS FOR TAILORING CARRIER POWER REQUIREMENTS ACCORDING TO AVAILABILITY IN LAYERED MODULATION SYSTEMS,� filed on Apr. 25, 2005, by Ernest C. Chen, Paul R. Anderson and Joseph Santoru, now issued as U.S. Pat. No. 7,173,977, which is a National Stage Application of PCT Application US03/32751, filed Oct. 15, 2003, which claims priority to Provisional Patent Application 60/421,333, entitled �METHOD AND APPARATUS FOR TAILORING CARRIER POWER REQUIREMENTS ACCORDING TO AVAILABILITY IN LAYERED MODULATION SYSTEMS,� filed Oct. 25, 2002, by Ernest C. Chen, Paul R. Anderson and Joseph Santoru, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/532,509, entitled �ESTIMATING THE OPERATING POINT ON A NONLINEAR TRAVELING WAVE TUBE AMPLIFIER,� filed on Apr. 25, 2005, by Ernest C. Chen and Shamik Maitra, now issued as U.S. Pat. No. 7,230,480, which is a National Stage Application of PCT Application US03/33130 filed Oct. 17, 2003, and which claims priority to Provisional Patent Application 60/421,289, entitled �ESTIMATING THE OPERATING POINT ON A NONLINEAR TRAVELING WAVE TUBE AMPLIFIER,� filed Oct. 25, 2002, by Ernest C. Chen and Shamik Maitra, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/519,322, entitled �IMPROVING HIERARCHICAL 8PSK PERFORMANCE,� filed on Dec. 23, 2004 by Ernest C. Chen and Joseph Santoru, which is a National Stage Application of PCT US03/020862 filed Jul. 1, 2003, which claims priority to Provisional Patent Application 60/392,861, filed Jul. 1, 2002 and Provisional Patent Application 60/392,860, filed Jul. 1, 2002, and which is also related to application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/519,375, entitled �METHOD AND APPARATUS FOR LAYERED MODULATION,� filed on Jul. 3,2003, by Ernest C. Chen and Joseph Santoru, which is a National Stage Application of PCT US03/20847, filed Jul. 3, 2003, which claims priority to Provisional Patent Application 60/393,437 filed Jul. 3, 2002, and which is related to application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524;
Application Ser. No. 10/692,539, entitled �ON-LINE PHASE NOISE MEASUREMENT FOR LAYERED MODULATION�, filed Oct. 24, 2003, by Ernest C. Chen, which claims priority from Provisional Patent Application 60/421,291, filed Oct. 25, 2002, entitled �ON-LINE PHASE NOISE MEASUREMENT FOR LAYERED MODULATION�; and
Application Ser. No. 10/692,491, entitled �ONLINE OUTPUT MULTIPLEXER FILTER MEASUREMENT,� filed on Oct. 24, 2003, by Ernest C. Chen, which claims priority to Provisional Patent Application 60/421,290, filed Oct. 25, 2002, and which is a continuation-in-part of Application Ser. No. 09/844,401, entitled �LAYERED MODULATION FOR DIGITAL SIGNALS,� filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524.
The present invention relates generally to systems for receiving digital signals, and in particular, to systems for receiving layered modulation in digital signals.
As various digital signal communication systems and services evolve, there is a burgeoning demand for increased data throughput and added services. However, it is more difficult to implement improvements in old systems and new services when it is necessary to replace existing legacy hardware, such as transmitters and receivers. New systems and services are advantaged when they can utilize existing legacy hardware. In the realm of wireless communications, this principle is further highlighted by the limited availability of electromagnetic spectrum. Thus, it is not possible (or at least not practical) to merely transmit enhanced or additional data at a new frequency.
The conventional method of increasing spectral capacity is to move to a higher-order modulation, such as from quadrature phase shift keying (QPSK) to eight phase shift keying (8PSK) or sixteen quadrature amplitude modulation (16QAM). Unfortunately, QPSK receivers cannot demodulate 8PSK or 16QAM signals. As a result, legacy customers with QPSK receivers must upgrade their receivers in order to continue to receive any signals transmitted with an 8PSK or 16QAM modulation.
Layered modulation enables systems and methods of transmitting signals to accommodate enhanced and increased data throughput without requiring additional frequency bands. Systems using layered modulation can provide enhanced and increased throughput signals for new receivers while remaining compatible with legacy receivers. Newer layered modulation techniques (such as detailed in U.S. patent application Ser. No. 09/844,401, filed Apr. 27, 2001, and entitled �LAYERED MODULATION FOR DIGITAL SIGNALS) also provide the unique advantage of allowing transmission signals to be upgraded from a source separate from the legacy transmitter. In other words, the layered signals can be asynchronous and/or non-coherent.
Related receiver systems for layered signals have also been described, such as those found in U.S. Pat. No. 4,039,961, which is incorporated by reference herein. However, such receiver systems are based on analog circuits, synchronized by a voltage control oscillator. In addition, such receiver systems are limited because they are designed to only receive coherent layered signals, i.e. signals that are synchronously produced.
Accommodating legacy receivers is also an important consideration when layered modulation is employed to enhance a preexisting system. Although proper design of the layered modulation signal can enable legacy receivers to receive legacy layers of the signal, the new signal layers will not be accessible by legacy receivers. In addition, it may not always be possible (or preferable) to accommodate the legacy receivers in designing the new layered modulation signal. In which case, the legacy receivers would be rendered incompatible with the new layered modulation signal.
There is a need for systems and methods for receiving and processing the layered modulation signals. There is also a need for systems and methods to enable legacy receivers to receive all layers of the layered signal. There is further a need for systems and methods which enable legacy receivers to be operable if the layered modulation signal is otherwise incompatible with the legacy receiver. The present invention meets these needs.
SUMMARY OF THE INVENTION The present invention provides a flexible and expandable apparatus that can be implemented with high speed logic circuit technology capable of performing demodulator functions and processing of received layered modulation signals in real-time. The invention utilizes high speed digitization of the incoming signal to prepare it for further high-speed digital processing. The invention enables a receive system architecture wherein the incoming signal is split and separately directed to distinct integrated receiver/decoders (IRDs). The system facilitates compatibility with legacy IRDs. One legacy IRD can be used to receive the upper modulation layer as it would receive a conventional unlayered signal. In this IRD the lower modulation layer is ignored as noise. A second legacy IRD receives a signal that has been preprocessed to extract and convert the lower modulation signal to a legacy IRD compatible signal.
An exemplary apparatus comprises a tuner for receiving a layered signal and producing a layered in-phase signal and a layered quadrature signal therefrom, an analog-to-digital converter for digitizing the layered in-phase signal and the layered quadrature signal, a processor for decoding the layered in-phase signal and the layered quadrature signal to produce a single layer in-phase signal and a single layer quadrature signal, a digital-to-analog encoder for converting the single layer in-phase signal and the single layer quadrature signal to a single layer in-phase analog signal and a single layer quadrature analog signal and a modulator for modulating the single layer in-phase analog signal and the single layer quadrature analog signal to produce a single layer signal.
Preferably, the layered signal is designed to be compatible with a legacy receiver such that at least one signal layer is decodeable directly from the layered signal with the legacy receiver. The apparatus produces a single layer signal that is also decodeable with a legacy receiver.
To facilitate high speed signal processing, the processor can comprise a logic circuit. Decoding by the processor can start with match filtering the layered in-phase signal and the layered quadrature signal.
In one embodiment, the processor demodulates and decodes an upper layer signal from the layered in-phase signal and the layered quadrature signal. The processor further produces an ideal noise free upper layer signal including an ideal in-phase upper layer signal and an ideal quadrature upper layer signal from the decoded upper layer signal and subtracts the ideal in-phase upper layer signal and the ideal quadrature upper layer signal from the layered in-phase signal and the layered quadrature signal, respectively, to produce the single lower layer in-phase signal and the single lower layer quadrature signal. In a further embodiment, the layered in-phase signal and the layered quadrature signal are delayed to synchronize the subtraction.
In other embodiments, producing the ideal upper layer signal comprises signal processing the ideal in-phase upper layer signal and the ideal quadrature upper layer signal. Signal processing the ideal upper layer can include many elements, including pulse shaping the ideal in-phase upper layer signal and the ideal quadrature upper layer signal. Signal mapping to account for transmission distortions of the layered analog signal can also be applied to the ideal in-phase upper layer signal and the ideal quadrature upper layer signal. The ideal upper layer signal can also be processed by amplitude and phase matching with the layered signal to improve signal subtraction results.
FIGS. 1A-1C illustrate the relationship of signal layers in a layered modulation transmission;
FIGS. 2A-2C illustrate a signal constellation of a second transmission layer over a first transmission layer non-coherently;
FIG. 3 is a block diagram for a typical transmission system for a receiver of the invention;
FIG. 4 is a block diagram of a receiving architecture of the invention;
FIG. 5 is a block diagram of a layered modulation decoder of the invention; and
FIG. 6 is a method of a layered modulation decoding according to the invention.
The present invention provides for the reception of non-coherent legacy layered modulation signals using legacy receivers. The signal layers can be independently modulated and coded. Signal layers which are otherwise incompatible with the legacy receiver are preprocessed in a layered modulation decoder to convert them to a compatible format. Thus, all layers of the layered modulation signal can be received by splitting the incoming signal and directing it to different legacy receivers, preprocessing as necessary to extract the desired layer and present it in a compatible format. Preferably, at least one layer of the signal is compatible with a legacy receiver without being preprocessed.
2. Layered Signals
FIGS. 1A-1C and FIGS. 2A-2C illustrate a QPSK signal format in a two-layer example. FIGS. 1A-1C illustrate the basic relationship of signal layers in a layered modulation transmission. FIG. 1A illustrates a upper layer signal constellation 100 of a transmission signal showing the signal points or symbols 102. FIG. 1B illustrates the lower layer signal constellation of symbols 104 over the upper layer signal constellation 100 where the layers are coherent. FIG. 1C illustrates a lower signal layer 106 of a lower transmission layer over the upper layer constellation where the layers may be non-coherent. The lower layer 106 rotates about the upper layer constellation 102 due to the relative modulating frequencies of the two layers in a non-coherent transmission. Both the upper and lower layers rotate about the origin due to the upper layer modulation frequency as described by path 108.
FIGS. 2A-2C illustrate a signal constellation of a lower transmission layer over the upper transmission layer after upper layer demodulation. FIG. 2A shows the constellation 200 before the upper carrier recovery loop (CRL) and FIG. 2B shows the constellation 200 after CRL. In this case, the signal points of the lower layer are rings 202. FIG. 2C depicts a phase distribution of the received signal with respect to nodes 102. As mentioned above, relative modulating frequencies cause the lower layer constellation to rotate around the nodes of the upper layer constellation. After the lower layer CRL this rotation is eliminated. The radius of the lower layer constellation is determined by its power level. The thickness of the rings 202 is determined by the carrier to noise ratio (CNR) of the lower layer.
FIG. 3 is a block diagram for a typical system 300 of transmitting and receiving layered signals. Separate transmitters 316A, 316B, as may be located on any suitable platform, such as satellites 306A, 306B, are used to non-coherently transmit different layers of a signal of the present invention. It is noted that the transmitters may also be positioned on the same platform. Uplink signals are typically transmitted to each satellite 306A, 306B from one or more transmit stations 304 via an antenna 302. The layered signals 308A, 308B (downlink signals) are received at receiver antennas 312, 320 (which can alternately be a single antenna), such as satellite dishes, each with a low noise block (LNB) 310, 318 (which can likewise be a single LNB) where they are then coupled to legacy integrated receiver/decoders (IRDs) 322. One of the layered signals 308A can be distinguished and processed directly by the legacy IRD 322. Note that one satellite dish with one LNB can also be used to receive both the upper and lower layers.
With the invention, one legacy IRD 314 has the received layered signals 308A, 308B preprocessed in the layered modulation decoder 324 to separate and convert one of the layered signals 308B to a format compatible with the legacy IRDs 314, 322. It should be noted that antennas 312, 320 can each comprise more than one directional receiving dish to receive layered signals 308A, 308B from separate satellites as will be detailed in the receiver system described hereafter.
In addition, because the signal layers may be transmitted non-coherently, separate transmission layers may be added at any time using different satellites 306A, 306B or other suitable platforms, such as ground based or high altitude platforms. Thus, any composite signal, including new additional signal layers will be backwards compatible with legacy receivers which will disregard the new signal layers. To ensure that the signals are distinguishable, the combined signal and noise level for the lower layer must be at or below the allowed noise floor for the upper layer. Alternate receiver systems employing the invention described here can be constructed to decode signals having more than two signal layers.
3. Receiver System
FIG. 4 is a block diagram of a receiving architecture for demonstrating the invention method. Emulated layered signals 400A, 400B are received by receiving dishes 402A, 402B (which can alternately be combined in a single dish with a single LNB). The signals 400A, 400B can each be transmitted by distinct transmitters from a single or separate satellites, but they exist in interfering frequency bands, e.g. 12.5 GHz. The received layered signals 400A, 400B are then directed through respective low noise blocks (LNBs) 404A, 404B and attenuators 406A, 406B. The LNBs 404A, 404B convert each of the received layered signals 400A, 400B to an intermediate frequency range, e.g. 950-1450 MHz. The layered signals are combined at the summation block 408, with their relative power levels adjusted by the attenuators 406A, 406B.
It should be noted that the details regarding the reception of the layered signal up to the summation block 408 are not critical to the operation of the invention and shown only as one example. Many designs are possible. For example, as previously mentioned, the same receiver dish can be used for both layered signals 400A, 400B. The result of two acceptably interfering layered signals on the same input is the only requirement.
The combined layered signals 400A, 400B can then be split at splitter 410 to direct the layered signal to alternate legacy IRDs 412A, 412B. One of the legacy IRDs 412A demodulates and decodes the upper layer signal of the signals 400A, 400B and ignores the other as noise. The decoded upper layer signal is then delivered to a display 414A. The other legacy IRD 412B has the layered signals 400A, 400B preprocessed by a layered modulation decoder 416 such that the lower layer signal of the signals 400A, 400B is converted to a signal compatible with the other legacy IRD 412B (and the upper layer signal of the signals 400A, 400B is effectively filtered out). The converted lower layer signal is then demodulated and decoded by the other legacy IRD 412B and the result delivered to a display 414B. Of course, alternate architectures can employ a single display switched between signals from the separate IRDs 412A, 412B.
4. Layered Modulation Decoder
FIG. 5 is a block diagram of a layered modulation decoder 416 of the invention. The layered modulation decoder 416 preprocesses an incoming layered signal to extract a lower layer signal and convert it to a signal that is decodable by a legacy receiver, as previously discussed.
After the splitter 410, the incoming layered signal is upper tuned to convert it to a baseband in-phase (I) and quadrature (Q) signal by tuner 500. The separate signals can then be filtered by a low pass filter 502 in preparation for digitizing. The signals are then digitized at a high sampling rate and sufficient resolution by an analog-to-digital converter (ADC) 504. A dual channel ADC 504 or separate ADCs can be used for the separate in-phase and quadrature signals. The digitized signals are then communicated to a processor 506.
The processor 506 for extracting a lower layer signal can be implemented as a logic circuit. The entering digitized in-phase and quadrature signals can be first split into two paths that will become the upper layer and composite layered signals. On the signal path for the upper layer, the in-phase and quadrature signals can first be passed through a frequency acquisition loop 508. The can then be filtered through a finite impulse response (FIR) matched filter 510. A demodulator 512 demodulates the signals, using carrier and timing recovery loops to produce demodulated layered in-phase and quadrature signals. The demodulated signals are then decoded by decoder 514 which can incorporate Viterbi decoding, deinterleaving and Reed-Solomon (RS) decoding functions as appropriate to accurately determine the upper layer symbols. The decoded upper layer symbols are then applied to an encoder 516 in order to produce an ideal upper layer signal (i.e. an upper layer signal transmitted without the noise and/or interference of the lower layer signal). The encoded signal emerges again as in-phase and quadrature signal components. A variety of signal processing techniques can be applied to these signals to produce the ideal upper layer.
The ideal upper layer signal can be filtered through an FIR matched filter 518. Characteristics of the transmission (e.g. amplifier nonlinearities, etc.) can be accounted for by signal maps 520, such as an amplitude modulation to amplitude modulation (AM/AM) map and/or an amplitude modulation to phase modulation map (AM/PM). These signal maps 520 can be updated to account for changes in the transmission characteristics of the satellite. The signal maps 520 are applied 522 to the encoded signals to simulate downlink transmission of an upper layer signal. Similarly, an additional FIR matched filter 526 can also be applied after accounting for transmission characteristics 522. In addition, an upper layer amplitude and phase matching function 528, driven by the demodulated layered signal and the ideal reconstructed upper layer signal, can also be used to generate matching coefficients. The matching coefficients are applied 524 to the reconstructed upper layer signal to ensure that it is appropriately scaled in magnitude and rotated in phase as compared to the layered signal, for maximum cancellation in the final signal subtraction.
Ultimately, the ideal reconstructed in-phase and quadrature signals for the upper layer are subtracted from the layered in-phase and quadrature signals that are produced by the demodulator at a subtractor 538. A timing and phase compensation function 532 is applied to the second layered path entering the processor 506, using information from the demodulator 512. A fixed delay 534 can be applied to the second layered signal path to determine the appropriate delay to align the layered and ideal signals to generate matching coefficients 528. The delayed layered signal is split and in one path, an FIR matched filter 530 can be applied to it before generating matching coefficients 528. The second delayed layered signal path is delayed again 536 to align it appropriately with the ideal upper layer signal for subtraction 538. The results of the subtraction are the in-phase and quadrature signals of the lower layer.
The in-phase and quadrature signals of the lower layer, output from the subtractor 538, are first converted to analog signals in an digital-to-analog converter (DAC) 540. The DAC essentially reverses the prior digitizing and therefore may use the same sampling rate and resolution. Following this, the analog form signals can be filtered by a low pass filter 542 and passed to a modulator 544 (e.g. a QPSK modulator) to produce the lower layer signal in a format for a legacy receiver to decode, as the output of the processor 416.
FIG. 6 describes a method of a layered modulation decoding according to the invention. A layered signal is received and a layered in-phase signal and a layered quadrature signal are produced from it at block 600. Next, the layered in-phase signal and the layered quadrature signal are digitized at block 602. At block 604, the layered in-phase signal and the layered quadrature signal are decoded to produce a single layer in-phase signal and a single layer quadrature signal. Then at block 606, the single layer in-phase signal and the single layer quadrature signal are converted to a single layer in-phase analog signal and a single layer quadrature analog signal. Finally, at block 608 the single layer in-phase analog signal and the single layer quadrature analog signal are modulated to produce a single layer signal.
CONCLUSION The foregoing description including the preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. The above specification, examples and data provide a complete description of the manufacture and use of the invention. Since many embodiments of the invention can be made without departing from the scope of the invention, the invention resides in the claims hereinafter appended.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3076180Oct 8, 1959Jan 29, 1963IbmMultiple bit phase-modulated storage loopUS3383598Feb 15, 1965May 14, 1968Space General CorpTransmitter for multiplexed phase modulated singaling systemUS3878468Jan 30, 1974Apr 15, 1975Bell Telephone Labor IncJoint equalization and carrier recovery adaptation in data transmission systemsUS3879664May 7, 1973Apr 22, 1975SignatronHigh speed digital communication receiverUS3974449Mar 21, 1975Aug 10, 1976Bell Telephone Laboratories, IncorporatedJoint decision feedback equalization and carrier recovery adaptation in data transmission systemsUS4039961Sep 8, 1975Aug 2, 1977Nippon Telegraph And Telephone Public CorporationDemodulator for combined digital amplitude and phase keyed modulation signalsUS4068186Jun 17, 1976Jan 10, 1978Kokusai Denshin Denwa Kabushiki KaishaCircuit for compensating for nonlinear characteristics in high-frequency amplifiersUS4213095Aug 4, 1978Jul 15, 1980Bell Telephone Laboratories, IncorporatedFeedforward nonlinear equalization of modulated data signalsUS4253184Nov 6, 1979Feb 24, 1981Bell Telephone Laboratories, IncorporatedPhase-jitter compensation using periodic harmonically related componentsUS4283684Apr 16, 1979Aug 11, 1981Kokusai Denshin Denwa Co., Ltd.Non-linearity compensating circuit for high-frequency amplifiersUS4384355Dec 5, 1980May 17, 1983Bell Telephone Laboratories, IncorporatedControl of coefficient drift for fractionally spaced equalizersUS4416015Dec 30, 1981Nov 15, 1983Bell Telephone Laboratories, IncorporatedTiming acquisition in voiceband data setsUS4422175Jun 11, 1981Dec 20, 1983Racal-Vadic, Inc.Constrained adaptive equalizerUS4484337Jul 19, 1982Nov 20, 1984Alain LeclertCarrier wave regenerating circuitUS4500984Sep 29, 1982Feb 19, 1985International Telecommunications Satellite OrganizationEqualizer for reducing crosstalk between two FDM/FM carriers in a satellite communications systemUS4519084Sep 29, 1982May 21, 1985At&T Bell LaboratoriesMatched filter for combating multipath fadingUS4594725Jun 28, 1984Jun 10, 1986U.S. Philips CorporationCombined adaptive equalization and demodulation circuitUS4628507Apr 12, 1984Dec 9, 1986Nec CorporationBit error detection circuit for PSK-modulated carrier waveUS4637017May 21, 1984Jan 13, 1987Communications Satellite CorporationMonitoring of input backoff in time division multiple access communication satellitesUS4647873Jul 19, 1985Mar 3, 1987General Dynamics, Pomona DivisionAdaptive linear FM sweep corrective systemUS4654863May 23, 1985Mar 31, 1987At&T Bell LaboratoriesWideband adaptive predictionUS4670789Sep 10, 1985Jun 2, 1987U.S. Philips CorporationTelevision transmitterUS4709374Jul 5, 1984Nov 24, 1987American Telephone And Telegraph CompanyTechnique for decision-directed equalizer train/retrainUS4800573Nov 19, 1987Jan 24, 1989American Telephone And Telegraph CompanyEqualization arrangementUS4829543Dec 4, 1987May 9, 1989Motorola, Inc.Phase-coherent TDMA quadrature receiver for multipath fading channelsUS4835790Jun 23, 1988May 30, 1989Nec CorporationCarrier-to-noise detector for digital transmission systemsUS4847864Jun 22, 1988Jul 11, 1989American Telephone And Telegraph CompanyPhase jitter compensation arrangement using an adaptive IIR filterUS4860315Apr 20, 1988Aug 22, 1989Oki Electric Industry Co., Ltd.ADPCM encoding and decoding circuitsUS4878030Oct 23, 1987Oct 31, 1989Ford Aerospace & Communications CorporationLinearizer for microwave amplifierUS4896369Dec 28, 1984Jan 23, 1990Harris CorporationOptimal satellite TWT power allocation process for achieving requested availability and maintaining stability in ALPC-type networksUS4918708Mar 17, 1987Apr 17, 1990Hewlett-Packard CompanyAnalysis of digital radio transmissionsUS4993047Sep 5, 1989Feb 12, 1991At&T Bell LaboratoriesVolterra linearizer for digital transmissionUS5043734Dec 22, 1988Aug 27, 1991Hughes Aircraft CompanyDiscrete autofocus for ultra-high resolution synthetic aperture radarUS5088110Mar 15, 1989Feb 11, 1992Telecommunications Radioelectriques Et Telephoniques T.R.T.Baseband-controlled passband equalizing arrangementUS5111155Mar 4, 1991May 5, 1992Motorola, Inc.Distortion compensation means and methodUS5121414Aug 9, 1990Jun 9, 1992Motorola, Inc.Carrier frequency offset equalizationUS5199047Oct 22, 1990Mar 30, 1993U.S. Philips CorporationReceiver for a digital transmission systemUS5206889Jan 17, 1992Apr 27, 1993Hewlett-Packard CompanyTiming interpolatorUS5221908Nov 29, 1991Jun 22, 1993General Electric Co.Wideband integrated distortion equalizerUS5229765May 8, 1991Jul 20, 1993Halliburton Logging Services, Inc.SP noise cancellation techniqueUS5233632May 10, 1991Aug 3, 1993Motorola, Inc.Communication system receiver apparatus and method for fast carrier acquisitionUS5237292Jul 1, 1992Aug 17, 1993Space Systems/LoralQuadrature amplitude modulation system with compensation for transmission system characteristicsUS5285474Jun 12, 1992Feb 8, 1994The Board Of Trustees Of The Leland Stanford, Junior UniversityMethod for equalizing a multicarrier signal in a multicarrier communication systemUS5285480Sep 3, 1991Feb 8, 1994General Electric CompanyAdaptive MLSE-VA receiver for digital cellular radioUS5317599Dec 3, 1992May 31, 1994Nec CorporationMethod and circuit for detecting CN ratio of QPSK signalUS5329311May 11, 1993Jul 12, 1994The University Of British ColumbiaSystem for determining noise content of a video signal in the disclosureUS5337014Dec 24, 1992Aug 9, 1994Harris CorporationPhase noise measurements utilizing a frequency down conversion/multiplier, direct spectrum measurement techniqueUS5353307Jul 20, 1993Oct 4, 1994General Electric CompanyAutomatic simulcast alignmentUS5412325Dec 23, 1993May 2, 1995Hughes Aircraft CompanyPhase noise measurement system and methodUS5430770Apr 22, 1994Jul 4, 1995Rockwell International Corp.Method and apparatus for composite signal separation and PSK/AM/FM demodulationUS5450623Sep 17, 1993Sep 12, 1995Leader Electronics Corp.CN ratio measuring apparatusUS5467197Dec 16, 1993Nov 14, 1995Seiko CorporationDual communication mode video tape recorderUS5471508Aug 20, 1993Nov 28, 1995Hitachi America, Ltd.In a communication receiverUS5493307May 26, 1995Feb 20, 1996Nec CorporationSidelobe cancelerUS5513215Sep 20, 1993Apr 30, 1996Glenayre Electronics, Inc.High speed simulcast data system using adaptive compensationUS5555257May 16, 1995Sep 10, 1996Ericsson Ge Mobile Communications Inc.Cellular/satellite communications system with improved frequency re-useUS5577067Feb 22, 1994Nov 19, 1996Comsonics, Inc.Data acquisition and storage system for telecommunication equipment to facilitate alignment and realignment of the telecommunications equipmentUS5577087Oct 27, 1992Nov 19, 1996Nec CorporationVariable modulation communication method and systemUS5579344Nov 14, 1995Nov 26, 1996Kabushiki Kaisha ToshibaAdaptive maximum likelihood sequence estimation apparatus and adaptive maximum likelihood sequence estimation methodUS5581229Jul 19, 1993Dec 3, 1996Hunt Technologies, Inc.Communication system for a power distribution lineUS5592481Jun 6, 1995Jan 7, 1997Globalstar L.P.Multiple satellite repeater capacity loading with multiple spread spectrum gateway antennasUS5602868May 22, 1995Feb 11, 1997Motorola, Inc.Multiple-modulation communication systemUS5603084Mar 2, 1995Feb 11, 1997Ericsson Inc.Method and apparatus for remotely programming a cellular radiotelephoneUS5606286Jul 27, 1995Feb 25, 1997Bains; Devendar S.Predistortion linearizationUS5608331Jun 6, 1995Mar 4, 1997Hughes ElectronicsNoise measurement test systemUS5625640Sep 16, 1994Apr 29, 1997Hughes ElectronicsApparatus for and method of broadcast satellite network return-link signal transmissionUS5642358Apr 8, 1994Jun 24, 1997Ericsson Inc.Multiple beamwidth phased arrayUS5644592Apr 24, 1995Jul 1, 1997California Institute Of TechnologyParallel interference cancellation for CDMA applicationsUS5648955Jun 7, 1995Jul 15, 1997Omnipoint CorporationIn a time division multiple access communication systemUS5732113Jun 20, 1996Mar 24, 1998Stanford UniversityTiming and frequency synchronization of OFDM signalsUS5793818Jun 7, 1995Aug 11, 1998Discovision AssociatesCircuit for processing modulated signalsUS5815531Jun 12, 1996Sep 29, 1998Ericsson Inc.Transmitter for encoded data bitsUS5819157Jun 18, 1997Oct 6, 1998Lsi Logic CorporationReduced power tuner chip with integrated voltage regulator for a satellite receiver systemUS5828710Dec 11, 1995Oct 27, 1998Delco Electronics CorporationAFC frequency synchronization networkUS5848060Aug 21, 1995Dec 8, 1998Ericsson Inc.Cellular/satellite communications system with improved frequency re-useUS5870439Jun 18, 1997Feb 9, 1999Lsi Logic CorporationSatellite receiver tuner chip having reduced digital noise interferenceUS5870443Mar 19, 1997Feb 9, 1999Hughes Electronics CorporationSymbol timing recovery and tracking method for burst-mode digital communicationsUS5937004Oct 13, 1994Aug 10, 1999Fasulo, Ii; Albert JosephApparatus and method for verifying performance of digital processing board of an RF receiverUS5940025Sep 15, 1997Aug 17, 1999Raytheon CompanyNoise cancellation method and apparatusUS5940750Sep 3, 1997Aug 17, 1999Wang; Guan-WuLow-cost low noise block down-converter with a self-oscillating mixer for satellite broadcast receiversUS5946625Oct 10, 1996Aug 31, 1999Ericsson, Inc.Method for improving co-channel interference in a cellular systemUS5952834Jan 14, 1998Sep 14, 1999Advanced Testing Technologies, Inc.Low noise signal synthesizer and phase noise measurement systemUS5956373Nov 14, 1996Sep 21, 1999Usa Digital Radio Partners, L.P.AM compatible digital audio broadcasting signal transmision using digitally modulated orthogonal noise-like sequencesUS5960040Dec 5, 1996Sep 28, 1999Raytheon CompanyCommunication signal processors and methodsUS5963845Nov 21, 1995Oct 5, 1999Alcatel EspaceSatellite payload with integrated transparent channelsUS5966048Nov 25, 1997Oct 12, 1999Hughes Electronics CorporationLow IMD amplification method and apparatusUS5966186Jul 11, 1997Oct 12, 1999Kabushiki Kaisha ToshibaDigital broadcast receiving device capable of indicating a receiving signal strength or qualityUS5966412Jun 30, 1997Oct 12, 1999Thomson Consumer Electronics, Inc.Apparatus and method for processing a Quadrature Amplitude Modulated (QAM) signalUS5970098Oct 2, 1997Oct 19, 1999Globespan Technologies, Inc.Multilevel encoderUS5970156Feb 14, 1997Oct 19, 1999Telefonaktiebolaget Lm EricssonMethod and apparatus for reducing periodic interference in audio signalsUS5970429Aug 8, 1997Oct 19, 1999Lucent Technologies, Inc.Method and apparatus for measuring electrical noise in devicesUS5978652Jan 10, 1997Nov 2, 1999Space Systems/Loral, Inc.Common direct broadcasting service systemUS5987068Nov 8, 1996Nov 16, 1999Motorola, Inc.Method and apparatus for enhanced communication capability while maintaining standard channel modulation compatibilityUS5995832Oct 28, 1998Nov 30, 1999Celsat America, Inc.Communications systemUS5999793Jun 18, 1997Dec 7, 1999Lsi Logic CorporationSatellite receiver tuner chip with frequency synthesizer having an externally configurable charge pumpUS6002713Oct 22, 1997Dec 14, 1999Pc Tel, Inc.PCM modem equalizer with adaptive compensation for robbed bit signallingUS6008692Aug 15, 1997Dec 28, 1999Nokia Technology GmbhCarrier wave synchronization for multi-level two-dimensional modulation alphabetsUS6018556Nov 12, 1997Jan 25, 2000Dsp Group, Inc.Programmable loop filter for carrier recovery in a radio receiverUS7073116 *Nov 22, 2000Jul 4, 2006Thomson LicensingError detection/correction coding for hierarchical QAM transmission systemsUS7079585 *Nov 22, 2000Jul 18, 2006Thomson LicensingGray encoding for hierarchical QAM transmission systemsUSRE31351Dec 24, 1981Aug 16, 1983Bell Telephone Laboratories, IncorporatedFeedback nonlinear equalization of modulated data signals* Cited by examinerNon-Patent CitationsReference1Arslan, H; Molnar, K: "Iterative Co-channel Interference Cancellation in Narrowband Mobile Radio Systems", Emerging Technologies Symposium: Broadband, Wireless Internet Access, 2000 IEEE Apr. 10-11, 2000, Piscataway, New Jersey, US, XP010538900.2Arslan, Huseyin and Molnar, Karl; "Co-channel Interference Cancellation with Successive Cancellation in Narrowband TDMA Systems"; Wireless Communications and Networking Conference; 2000 IEEE; Sep. 23-28, 2000; Piscataway, New Jersey, USA; vol. 3; pp. 1070-1074; XP010532692; ISBN: 0-7803-6596-8.3Arslan, Huseyin and Molnar, Karl; "Successive Cancellation of Adjacent Channel Signals in FDMA/TDMA Digital Mobile Radio Systems"; Vehicular Technology Conference; 48th IEEE VTC; Ottawa, Canada; May 18-21, 1998; New York, New York, USA; vol. 3; May 18, 1998; pp. 1720-1724; XP010288123.4Canadian Office Action dated Apr. 22, 2008 in Canadian counterpart Application No. 2502924 corresponding to U.S. Appl. No. 10/532,619 filed Apr. 25, 2005 by Ernest C. Chen.5Canadian Office Action dated Sep. 12, 2007 in Canadian counterpart Application No. 2491259 of corresponding U.S. Appl. No. 10/519,375 filed Jul. 3, 2003 by Ernest Chen et al.6Chen, Ernest et al.; "DVB-S2 Backward-Compatible Modes: A Bridge Between the Present and the Future"; International Journal of Satellite Communications and Networking; vol. 22, Issue 3, pp. 341-365; published 2004 by John Wiley & Sons, Ltd.7Combarel, L. and Lavan, E.; "HD-SAT (Race 2075): HDTV Broadcasting over KA-Band Satellite, Cable and MMDS"; International Broadcasting Convention; 1994; pp. 633-640; XP006505143.8Combarel, L. et al.; HD-SAT Modems for the Satellite Broadcasting in the 20 GHz Frequency Band; IEEE Transactions on Consumer Electronics; vol. 41, Issue 4; Nov. 1995; pp. 991-999.9Earth Station Technology; 1986; pp. 404-412; XP-002248387.10El-Gamal, Abbas and Cover, Thomas M.; "Multiple User Information Theory"; Proceedings of IEEE; vol. 68, No. 12; Dec. 1980; pp. 1466-1483; XP007904837.11EPO Communication dated Apr. 4, 2008 in European counterpart Application No. 03757359.9 corresponding to U.S. Appl. No. 10/165,710 filed Jun. 7, 2002 by Ernest Chen.12EPO Communication dated Aug. 3, 2007 in European counterpart Application No. 03794510.2 of corresponding U.S. Appl. No. 10/236,414 filed Sep. 6, 2002 by Ernest Chen et al.13EPO Communication dated Feb. 26, 2008 in European counterpart Application No. 04256234.8 corresponding to U.S. Appl. No. 10/962,346 filed Oct. 8, 2004 by Ernest Chen.14EPO Communication dated Feb. 7, 2008 in European counterpart Application No. 03742400.9 and received from European representative on Feb. 14, 2008 and corresponding to U.S. Appl. No. 10/519,322 filed Dec. 23, 2004 by Ernest Chen et al.15EPO Communication dated Mar. 11, 2008 in European counterpart Application No. 03777694.5 of corresponding U.S. Appl. No. 10/532,509 filed Oct. 17, 2003 by Ernest Chen et al., now issued as Patent No. 7,230,480.16EPO Communication dated Mar. 7, 2008 in European counterpart Application No. 03742393.6 of corresponding U.S. Appl. No. 10/519,375 filed Jul. 3, 2003 by Ernest Chen et al.17EPO Communication dated May 6, 2008 in European counterpart Application No. 03774848.0 corresponding to U.S. Appl. No. 10/532,582 filed Apr. 25, 2005 by Ernest Chen et al., now issued Feb. 6, 2007 as U.S. Patent No. 7,173,977.18EPO Communication dated May 6, 2008 in European counterpart Application No. 03777627.5 corresponding to U.S. Appl. No. 10/532,619 filed Apr. 25, 2005 by Ernest Chen.19EPO Search Report and Search Opinion dated Jun. 13, 2008 in European counterpart Application No. 07075745.5 corresponding to U.S. Appl. No. 09/844,401 filed Apr. 27, 2001 by Ernest C. Chen, now issued Apr. 24, 2007 as U.S. Patent No. 7,209,524.20EPO Summons to attend Oral Proceedings dated Jul. 18, 2008 in European counterpart Application No. 02728894.3 corresponding to U.S. Appl. No. 09/844,401 filed Apr. 27, 2001 by Ernest Chen, now issued Apr. 24, 2007 as U.S. Patent No. 7,209,524.21Fang, T. et al.; "Fourth-Power Law Clock Recovery with Prefiltering", Proceedings of the International Conference on Communications (ICC), Geneva, May 23-26, 1993, New York, IEEE, US, vol. 3, May 23, 1993, pp. 811-815, XP010137089, ISBN:0-7803-0950-2, Section I, Introduction.22Final Rejection dated Jun. 24, 2008 in U.S. Appl. No. 10/519,375 filed Dec. 22, 2004 by Ernest C. Chen et al.23Janssen, G.J.M; Slimane, S.B.: "Performance of a Multiuser Detector for M-PSK Signals Based on Successive Cancellation", ICC 2001, 2001 IEEE International Conference on Communications, Conference Record, Helsinky, Finland, Jun. 11-14, 2001, XP010552960.24Japanese Office Action dated Mar. 4, 2008 in Japanese counterpart Application No. 2004-297297 corresponding to U.S. Appl. No. 10/962,346 filed Oct. 8, 2004 by Ernest Chen.25Mazzini, Gianluca: "Power Division Multiple Access", Universal Personal Communications, 1998, ICUPC 1998, IEEE 1998, International Conference on Florence, Italy, Oct. 5-9, 1998, New York, NY, US, IEEE, US Oct. 5, 1998, pp. 543-546, XP010314962 ISBN: 0-7803-5106-1.26Meyr, Heinrich et al.; "Digital Communication Receivers-Synchronization, Channel Estimation, and Signal Processing"; John Wiley & Sons, Inc.; 1998; pp. 212-213 and 217-218; XP 002364874.27Meyr, Heinrich et al.; "Digital Communication Receivers-Synchronization, Channel Estimation, and Signal Processing"; John Wiley & Sons, Inc.; 1998; pp. 610-6112; XP 002364876.28Non-final Communication dated Mar. 3, 2008 in U.S. Appl. No. 11/656,662 filed Jan. 22, 2007 by Ernest C. Chen et al.29Non-final Communication dated Oct. 16, 2007 in U.S. Appl. No. 10/962,346 filed Oct. 8, 2004 by Ernest Chen.30Non-Final Office Action dated Apr. 30, 2008 in U.S. Appl. No. 10/962,346 filed Oct. 8, 2004 by Ernest C. Chen.31Non-final Office Action dated Apr. 30, 2008 in U.S. Appl. No. 10/962,346 filed Oct. 8, 2004 by Ernest Chen.32Non-Final Office Action dated Jun. 17, 2008 in U.S. Appl. No. 10/913,927 filed Aug. 5, 2004 by Ernest C. Chen.33Non-final Office Communication dated Apr. 1, 2008 in U.S. Appl. No. 10/961,579, filed Oct. 8, 2004 filed by Ernest C. Chen.34Notice of Allowance dated Apr. 21, 2008 in U.S. Appl. No. 11/519,322 filed Dec. 23, 2004 by Ernest Chen et al.35Notice of Allowance dated Apr. 30, 2008 in U.S. Appl. No. 11/603,776 filed Nov. 22, 2006 by Ernest Chen et al.36Notice of Allowance dated Jun. 13, 2008 in U.S. Appl. No. 10/532,524 filed Apr. 25, 2005 by Ernest C. Chen et al.37Notice of Allowance dated Mar. 12, 2008 in U.S. Appl. No. 10/655,001 filed Jan. 18, 2007 by Weizheng Wang et al.38Notice of Allowance dated Mar. 25, 2008 in U.S. Appl. No. 11/653,517 filed Jan. 16, 2007 by Ernest C. Chen.39Notice of Allowance dated May 6, 2008 in U.S. Appl. No. 10/532,631 filed Apr. 25, 2005 by Paul R. Anderson et al.40Notice of Allowance dated May 6, 2008 in U.S. Appl. No. 10/532,632 filed Apr. 25, 2005 by Ernest Chen et al.41Notice of Allowance dated May. 22, 2008 in U.S. Appl. No. 10/532,619 filed May. 25, 2005 by Ernest Chen.42Palicot, J., Veillard, J.; "Possible Coding and Modulation Approaches to Improve Service Availability for Digital HDTV Satellite Broadcasting at 22 GHz"; IEEE Transactions on Consumer Electronics; Vol. 39, Issue 3; Aug. 1993; pp. 660-667.43Ramchandran, Kannan et al.: Multiresolution Broadcast for Digital HDTV Using Joint Source/Channel Coding, IEEE, vol. 11, No. 1, Jan. 1993, pp. 6-22.44Saleh, A.A.M. et al.: "Adaptive Linearization of Power Amplifiers in Digital Radio Systems", Bell System Technical Journal, American Telephone and Telegraph Co., New York, US, vol. 62, No. 4, Part 1, Apr. 1, 1983, pp. 1019-1033, XP002028354.45Scalart, Pascal; LeClerc, Michel; Fortier, Paul; Huynh Huu Tue; "Performance Analysis of a COFDM/FM In-band Digital Audio Broadcasting System"; IEEE Transactions on Broadcasting, IEEE Service Center; Piscataway, New Jersey, USA; vol. 43, No. 2; Jun. 1, 1997; pp. 191-198; XP011006070.46Scott, R. P. et al.; Ultralow Phase Noise Ti:sapphire Laser Rivals 100 MHz Crystal Oscillator; Nov. 11-15, 2001; IEEE-Leos; pp. 1-2.47Seskar, Ivan et al.; "Implementation Aspects for Successive Interface Cancellation in DS/CDMA Systems"; Wireless Networks; 1998; pp. 447-452.48Slimane, S.B.; Janssen, G.J.M.: "Power Optimization of M-PSK Cochannel Signals for a Narrowband Multiuser Detector", 2001 IEEE Pacific Rim Conference on Communications, Computer and Signal Processing, Victoria, B.C., Canada, Aug. 26-28, 2001, XP010560334.49Soong, A.C.K.; Krzymien, W.A.: "Performance of a Reference Symbol Assisted Multistage Successive Interference Cancelling Receiver in a Multicell CDMA Wireless System", Conference Record, Communication Theory Mini-Conference GlobeCom '95, IEEE Singapore Nov. 13-17, 1995, XP010159490.50Taiwanese Office Action dated May 14, 2008 in Taiwan counterpart Application No. 092129629 corresponding to U.S. Appl. No. 10/532,631 filed Apr. 25, 2005 by Paul R. Anderson et al.51The Authoritive Dictionary of IEEE Standards Terms; Seventh Edition, pp. 1047-definition of "signal" 2000.52U.S. Appl. No. 10/519,322, filed Dec. 23, 2004, Ernest C. Chen, Notice of Allowance dated Dec. 11, 2007.53U.S. Appl. No. 10/519,375, filed Dec. 22, 2004, Ernest C. Chen, Non-final Communication dated Dec. 27, 2007.54U.S. Appl. No. 10/532,619, filed Apr. 25, 2005, Ernest C. Chen, Notice of Allowance dated Dec. 26, 2007.55U.S. Appl. No. 10/532,631, filed Apr. 25, 2005, Paul R. Anderson, Non-final Communication dated Nov. 19, 2007.56U.S. Appl. No. 10/532,632, filed Apr. 25, 2003, Chen et al.57U.S. Appl. No. 10/532,632, filed Apr. 25, 2005, Ernest C. Chen, Notice of Allowance dated Jan. 7, 2008.58U.S. Appl. No. 10/691,032, filed Oct. 22, 2003, Weizheng Wang, Non-final Communication dated Nov. 16, 2007.59U.S. Appl. No. 10/692,491, filed Oct. 24, 2003, Ernest C. Chen.60U.S. Appl. No. 10/692,539, filed Oct. 24, 2003, Ernest C. Chen, Notice of Allowance dated Sep. 20, 2007.61U.S. Appl. No. 10/692,539, Oct. 24, 2003, Ernest C. Chen, Non-final Communication dated May 31, 2007.62U.S. Appl. No. 10/693,135, filed Oct. 24, 2003, Chen.63U.S. Appl. No. 10/913,927, filed Aug. 5, 2004, Ernest C. Chen, Non-final Communication dated Dec. 11, 2007.64U.S. Appl. No. 11/603,776, filed Nov. 22, 2006, Chen et al.65U.S. Appl. No. 11/603,776, filed Nov. 22, 2006, Ernest C. Chen, Notice of Allowance dated Jan. 2, 2008.66Wolcott, Ted J. et al.; "Uplink-Noise Limited Satellite Channels"; IEEE 1995; pp. 717-721; XP-00580915.Referenced byCiting PatentFiling datePublication dateApplicantTitleUS8804605Aug 31, 2012Aug 12, 2014The Directv Group, Inc.Feeder link configurations to support layered modulation for digital signalsUS20110182590 *Sep 8, 2008Jul 28, 2011Marco SecondiniOptical Signal Modulation* Cited by examinerClassifications U.S. Classification375/316, 375/343, 455/17, 375/261, 329/308, 375/320, 370/206, 375/349, 375/235International ClassificationH03K9/00Cooperative ClassificationH04L27/3488European ClassificationH04L27/34MLegal EventsDateCodeEventDescriptionMar 16, 2012FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google