CA2491259A1 - Method and apparatus for layered modulation - Google Patents
Method and apparatus for layered modulation Download PDFInfo
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- CA2491259A1 CA2491259A1 CA002491259A CA2491259A CA2491259A1 CA 2491259 A1 CA2491259 A1 CA 2491259A1 CA 002491259 A CA002491259 A CA 002491259A CA 2491259 A CA2491259 A CA 2491259A CA 2491259 A1 CA2491259 A1 CA 2491259A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/18—Phase-modulated carrier systems, i.e. using phase-shift keying
- H04L27/183—Multiresolution systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/20—Arrangements for detecting or preventing errors in the information received using signal quality detector
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/20—Arrangements for detecting or preventing errors in the information received using signal quality detector
- H04L1/208—Arrangements for detecting or preventing errors in the information received using signal quality detector involving signal re-encoding
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
- H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
- H04L27/3488—Multiresolution systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L2001/0098—Unequal error protection
Abstract
Improvements to a layered modulation (LM) implementation are disclosed.
The present invention discloses two implementations of LM, using single and multiple transponders per signal frequency, respectively. Layered hierarchical (H-8PSK) is a special case of LM. By re-encoding the high-priority (HP) portion of an H-8PSK signal, LM can improve carrier-to-noise ratio (CNR) or a H-8PSK
signal.
LM can be computer-simulated and a two-layered signal can be sequentially demodulated with a predict CNR performance. An LM signal can be simulated using live signals for off-line processing. In addition, a signal processing apparatus can process in real time LM signals emulated from live satellite signals.
The present invention discloses two implementations of LM, using single and multiple transponders per signal frequency, respectively. Layered hierarchical (H-8PSK) is a special case of LM. By re-encoding the high-priority (HP) portion of an H-8PSK signal, LM can improve carrier-to-noise ratio (CNR) or a H-8PSK
signal.
LM can be computer-simulated and a two-layered signal can be sequentially demodulated with a predict CNR performance. An LM signal can be simulated using live signals for off-line processing. In addition, a signal processing apparatus can process in real time LM signals emulated from live satellite signals.
Description
METHOD AND APPARATUS FOR LAYERED MODULATION
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to the following U.S. Provisional Patent Application, which is incorporated by reference herein:
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to the following U.S. Provisional Patent Application, which is incorporated by reference herein:
[0002] U.S. Provisional Patent Application Serial No. 60/393,437, filed on July 3, 2002, and entitled "LAYERED MODULATION SIMULATION RESULTS", by Ernest C. Chen et al.
[0003] This applications is related to the following co-pending patent applications, both of which applications are hereby incorporated by reference:
[0004] U.S. Patent Application Serial No. 09/844,401, filed on April 27, 2001, and entitled "LAYERED MODULATION FOR DIGITAL SIGNALS", by Ernest C.
Chen;
Chen;
[0005] U.S. Patent Application Serial No. 10/068,039, filed on February 5, 2002, and entitled "PREPROCESSING SIGNAL LAYERS IN A LAYERED
MODULATION DIGITAL SIGNAL SYSTEM TO USE LEGACY RECEIVERS", by Ernest C. Chen, et.al.;
MODULATION DIGITAL SIGNAL SYSTEM TO USE LEGACY RECEIVERS", by Ernest C. Chen, et.al.;
[0006] U.S. Patent Application Serial No. 10/068,047, filed on February S, 2002, and entitled "DUAL LAYER SIGNAL PROCESSING IN A LAYERED
MODULATION DIGITAL SIGNAL SYSTEM", by Ernest C. Chen, et.al.; and (0007] International Application No. PCT/LJS03/XX~CXX, filed on July 1, 2003, and entitled "IMPROVING HIERARCHICAL 8PSK PERFORMANCE", by Ernest C. Chen et al.
BACKGROUND OF THE INVENTION
1. Field of the Invention [0008] The present invention relates generally to systems and methods for transmitting and receiving digital signals, and in particular, to systems and methods S for broadcasting and receiving digital signals using layered modulation techniques.
2. Description of the Related Art [0009] Digital signal communication systems have been used in various fields, including digital TV signal transmission, either terrestrial or satellite.
MODULATION DIGITAL SIGNAL SYSTEM", by Ernest C. Chen, et.al.; and (0007] International Application No. PCT/LJS03/XX~CXX, filed on July 1, 2003, and entitled "IMPROVING HIERARCHICAL 8PSK PERFORMANCE", by Ernest C. Chen et al.
BACKGROUND OF THE INVENTION
1. Field of the Invention [0008] The present invention relates generally to systems and methods for transmitting and receiving digital signals, and in particular, to systems and methods S for broadcasting and receiving digital signals using layered modulation techniques.
2. Description of the Related Art [0009] Digital signal communication systems have been used in various fields, including digital TV signal transmission, either terrestrial or satellite.
[0010] As the 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 either improvement 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.
However, it is more difficult to implement either improvement 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.
[0011] 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 (BPSK) or sixteen quadrature amplitude modulation (16QAM).
Unfortunately, QPSK receivers cannot demodulate conventional 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.
Unfortunately, QPSK receivers cannot demodulate conventional 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.
[0012] Layered modulation techniques have been identified and developed to increase capacity, both in backwards compatible and non-backwards compatible implementations. Hierarchical modulation, particularly hierarchical 8PSK (H-8PSK), is also a special type of layer modulation that has been developed directed to a backwards compatible layered modulation implementation.
[0013] What is needed are systems and methods that improve layered modulation implementation, including hierarchical modulation implementations. Further, there is need for systems and methods that simulate the performance of layered modulation systems. The present invention satisfies these and other needs.
SUMMARY OF THE INVENTION
SUMMARY OF THE INVENTION
[0014] Improvements to a layered modulation (LM) implementation are disclosed.
The present invention relates to two implementations of LM, using single and multiple transponders per signal frequency, respectively. Layered hierarchical (H-8PSK) is a special case of LM. By re-encoding the high-priority (HP) portion of an H-8PSK signal, LM can improve carrier-to-noise ratio (CNR) of a H-8PSK
signal.
The present invention relates to two implementations of LM, using single and multiple transponders per signal frequency, respectively. Layered hierarchical (H-8PSK) is a special case of LM. By re-encoding the high-priority (HP) portion of an H-8PSK signal, LM can improve carrier-to-noise ratio (CNR) of a H-8PSK
signal.
[0015] In addition, LM can be computer-simulated and a two-layered signal can be sequentially demodulated with a predicted CNR performance. An LM signal can be emulated using live signals for off line processing. In addition, a signal processing apparatus can process in real time LM signals emulated from live satellite signals.
Embodiments of the invention comprise systems and methods for simulating a layer-modulated signal, including a hierarchically modulated signal. Such systems and methods are useful in the development of layer modulated systems because they allow convenient testing of proposed implementations and adjustments to existing systems and provide performance indicators at low cost.
Embodiments of the invention comprise systems and methods for simulating a layer-modulated signal, including a hierarchically modulated signal. Such systems and methods are useful in the development of layer modulated systems because they allow convenient testing of proposed implementations and adjustments to existing systems and provide performance indicators at low cost.
[0016] A typical method for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprises providing an upper layer signal comprising a first modulated bit stream, providing a lower layer signal comprising a second modulated bit stream, attenuating the lower layer signal and combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal. The upper and lower layers can be separately modulated in a laboratory environment or received from distinct antennas.
(0017] A first exemplary layer modulated system simulator comprises a first modulator for modulating a bit stream of the upper layer to produce an upper layer signal, a noise generator for adding noise to the upper layer signal, a second modulator for modulating a bit stream of a lower layer to produce a lower layer signal, an attenuator for attenuating the lower layer signal and a combiner for combining the noise-added upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal. This embodiment of the invention can be used for emulating a composite layer modulated signal entirely within a laboratory.
[0018] A second exemplary layer modulated system simulator comprises a first antenna for receiving the upper layer signal from a first satellite transponder, a first amplifier for amplifying the received upper layer signal, a second antenna for receiving the lower layer signal from a second satellite transponder, a second amplifier for amplifying the received lower layer signal, an attenuator for attenuating the received lower layer signal and a combiner for combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal.
This embodiment of the invention can be used for emulating a composite layer modulated signal from existing satellite signals.
BRIEF DESCRIPTION OF THE DRAWINGS
This embodiment of the invention can be used for emulating a composite layer modulated signal from existing satellite signals.
BRIEF DESCRIPTION OF THE DRAWINGS
(0019] Refernng now to the drawings in which like reference numbers represent corresponding parts throughout:
[0020] FIGS. lA-1C illustrate the relationship of signal layers in a layered modulation transmission;
[0021] FIGS. 2A-2C illustrate a signal constellation, along withits phase characteristics, of a second transmission layer over a first transmission layer non-coherently;
[0022] FIG. 3A is a diagram illustrating a QPSK signal constellation;
[0023] FIG. 3B is a diagram illustrating a non-uniform 8PSK signal constellation achieved through layered modulation;
[0024] FIG. 4A is a block diagram illustrating a layered modulation system using a single transponder;
[0025] FIG. 4B is a block diagram illustrating a layered modulation system using two transponders;
[0026] FIG. 5 is a block diagram of an exemplary receiver of a layered modulation signal;
[0027] FIG. 6 is a plot illustrating channel capacity shared between upper and lower layers;
[0028] FIGS. 7 is a block diagram of an exemplary receiver for hierarchical modulation;
[0029] FIGS. 8 is a block diagram of a second exemplary receivers for hierarchical modulation;
[0030] FIG. 9 is a block diagram of an exemplary layer modulated signal simulator;
[0031] FIG. 10 is a GUI of an exemplary layer modulated signal simulator showing BER test results;
[0032] FIG. 11A is a block diagram of an exemplary system for simulating a layer modulated signal in a laboratory;
[0033] FIG. 11B is a block diagram of an exemplary system for simulating a layer modulated signal using satellite signals;
[0034] FIG. 12 is flowchart of an exemplary method for simulating a layer modulated signal;
[0035] FIG. 13 is a flowchart of exemplary processing for a layer modulated signal;
[0036] FIG. 14 is power spectrum plot of an exemplary layer modulated signal;
[0037] FIGS. 15A-15C are plots illustrating upper layer symbol timing recovery for an exemplary layer modulated signal;
[0038] FIGS. 1 SD-15F are plots illustrating an upper layer symbol timing recovered signal for an exemplary layer modulated signal;
[0039] FIGS. 16A-16C are plots illustrating upper layer carrier recovery for an exemplary layer modulated signal;
[0040] FIGS. 16D-16F are plots illustrating an upper layer Garner recovered signal for an exemplary layer modulated signal;
[0041] FIG. 17A is a plot of uncoded upper layer bit errors at the demodulator output for an exemplary layer modulated signal;
[0042] FIG. 17B is a plot of upper layer byte errors at the Viterbi decoder output for an exemplary layer modulated signal;
[0043] FIG. 17C is a plot of upper layer byte errors at the de-interleaver output for an exemplary layer modulated signal;
_7_ [0044] FIG. 17D is a plot of upper layer errors correctable by a Reed-Solomon decoder for an exemplary layer modulated signal;
_7_ [0044] FIG. 17D is a plot of upper layer errors correctable by a Reed-Solomon decoder for an exemplary layer modulated signal;
[0045] FIG. 18 is a plot of power level matching for an exemplary layer modulated signal;
[0046] FIG. 19 is power spectrum plot of an extracted lower layer signal of an exemplary layer modulated signal;
[0047] FIGS. 20A-20C are plots illustrating lower layer symbol timing recovery for an exemplary layer modulated signal;
[0048] FIGS. 20D-20F are plots illustrating a lower layer symbol timing recovered signal for an exemplary layer modulated signal;
[0049] FIGS. 21A-21C are plots illustrating lower layer Garner recovery for an exemplary layer modulated signal;
[0050] FIGS. 21D-21F are plots illustrating a lower layer Garner recovered signal for an exemplary layer modulated signal;
[0051] FIG. 22A is a plot of uncoded lower layer bit errors at the demodulator output for an exemplary layer modulated signal;
[0052] FIG. 22B is a plot of lower layer byte errors at the Viterbi decoder output for an exemplary layer modulated signal;
[0053] FIG. 22C is a plot of lower layer byte errors at the de-interleaver output for an exemplary layer modulated signal;
[0054] FIG. 22D is a plot of upper layer errors correctable by a Reed-Solomon decoder for an exemplary layer modulated signal;
_g_ [0055] FIG. 23A is a plot of uncoded bit error rates for upper and lower layers of an exemplary layer modulated signal; and [0056] FIG. 23B is a plot of Viterbi decoder output bit error rates for upper and lower layers of an exemplary layer modulated signal.
S DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
S DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0057] In the following description, reference is made to the accompanying drawings which form a part hereof, and which show, by way of illustration, several embodiments of the present invention. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.
LAYERED AND HIERARCHICAL MODULATION/DEMODULATION
LAYERED AND HIERARCHICAL MODULATION/DEMODULATION
[0058] FIGS. lA-1C illustrate the basic relationship of signal layers in a layered modulation transmission. FIG. lA illustrates a first layer signal constellation 100 of a transmission signal showing the signal points or symbols 102. FIG. 1B
illustrates the second layer signal constellation of symbols 104 over the first layer signal constellation 100 where the layers are coherent. FIG. 1 C illustrates a second signal layer 106 of a second transmission layer over the first layer constellation where the layers may be non-coherent. The second layer 106 rotates about the first layer constellation 102 due to the relative modulating frequency of the two layers in a non-coherent transmission. Both the first and second layers rotate about the origin due to the first layer modulation frequency as described by path 108.
illustrates the second layer signal constellation of symbols 104 over the first layer signal constellation 100 where the layers are coherent. FIG. 1 C illustrates a second signal layer 106 of a second transmission layer over the first layer constellation where the layers may be non-coherent. The second layer 106 rotates about the first layer constellation 102 due to the relative modulating frequency of the two layers in a non-coherent transmission. Both the first and second layers rotate about the origin due to the first layer modulation frequency as described by path 108.
[0059] FIGS. 2A-2C illustrate a signal constellation of a second transmission layer over the first transmission layer after first layer demodulation. FIG. 2A
shows the constellation 200 before the first carrier recovery loop (CRL) and FIG. 2B
shows the constellation 200 after CRL. In this case, the signal points of the second layer are actually rings 202. FIG. 2C depicts a phase distribution of the received signal with respect to nodes 102. A relative modulating frequency causes the second layer constellation to rotate around the nodes of the first layer constellation.
After the second layer CRL this rotation is eliminated. The radius of the second layer constellation is determined by its power level. The thickness of the rings 202 is determined by the Garner to noise ratio (CNR) of the second layer. As the two layers are non-coherent, the second layer may also be used to transmit analog or digital signals. A special case of layered modulation is found in hierarchical modulation, such as hierarchical non-uniform 8PSK.
shows the constellation 200 before the first carrier recovery loop (CRL) and FIG. 2B
shows the constellation 200 after CRL. In this case, the signal points of the second layer are actually rings 202. FIG. 2C depicts a phase distribution of the received signal with respect to nodes 102. A relative modulating frequency causes the second layer constellation to rotate around the nodes of the first layer constellation.
After the second layer CRL this rotation is eliminated. The radius of the second layer constellation is determined by its power level. The thickness of the rings 202 is determined by the Garner to noise ratio (CNR) of the second layer. As the two layers are non-coherent, the second layer may also be used to transmit analog or digital signals. A special case of layered modulation is found in hierarchical modulation, such as hierarchical non-uniform 8PSK.
[0060] FIG. 3A is a diagram illustrating a signal constellation for a QPSK HP
data signal. The signal constellation includes four possible signal outcomes 302 for A and B wherein {A,B} _ {0,0} (point 302A in the first quadrant), { 1,0} (point 302B
in the second quadrant), {1,1} (point 302C in the third quadrant), and {0,1} (point 302D in the fourth quadrant). An incoming and demodulated signal mapped to one of quadrants (I-IV) and the value for {A,B} (and hence, the value for the relevant portion of the HP data stream) is determined therefrom.
data signal. The signal constellation includes four possible signal outcomes 302 for A and B wherein {A,B} _ {0,0} (point 302A in the first quadrant), { 1,0} (point 302B
in the second quadrant), {1,1} (point 302C in the third quadrant), and {0,1} (point 302D in the fourth quadrant). An incoming and demodulated signal mapped to one of quadrants (I-IV) and the value for {A,B} (and hence, the value for the relevant portion of the HP data stream) is determined therefrom.
[0061] FIG. 3B is a diagram illustrating an 8PSK constellation created by addition of an LP data stream (represented by "C"). The application of hierarchical modulation adds two possible data values for "C" (C = {1,0}) to each of the outcomes 302A-302D. For example, outcome 302A ({A,B} _ {0,0}) is expanded to an outcome pair 304A and 304A' ({A,B,C} _ {0,0,1 } and {0,0,0}), respectively, with the members of the pair separated by an angle 8 from {A,B}. This expands the signal constellation to include 8 nodes 104A-104D (each shown as solid dots).
[0062] If the angle 8 is small enough, a legacy QPSK signal will receive both {A,B,C} _ {0,0,1} and {0,0,0} as {A,B} _ {0,0}. Only receivers capable of performing the second hierarchical level of modulation (LP) can extract the value for {C} as either {0} or {1}. This hierarchical signal structure has been termed "non-uniform" 8PSK.
[0063] The choice of the variable 8 depends on a variety of factors. FIG. 3B, for example, presents the idealized data points without noise. Noise and errors in the transmission and/or reception of the signal vary the actual position of the nodes 304A-304D and 304A'-304D' in FIG. 3B. Noise regions 306 surrounding each node indicate S areas in the constellation where the measured data may actually reside. The ability of the receiver to detect the symbols and accurately represent them depends on the angle 8, the power of the signal (e.g. the Garner), represented by r~, and the noise (which can be represented by r"). As can be seen by inspecting FIG. 3B, interference of LP
into HP is reduced as signal power increases, or as 8 decreases. The performance of this hierarchical modulating system can be expressed in terms of its carrier to interference ratio (C/1).
into HP is reduced as signal power increases, or as 8 decreases. The performance of this hierarchical modulating system can be expressed in terms of its carrier to interference ratio (C/1).
[0064] With a layered-type demodulation as in this invention, the noise contributed by UL symbol errors to the extracted LL signal is avoided. With a Layered modulation mapping, the LP bit value for the 8 nodes alternates between 0 and around the circle, i.e., X0,1,0,1,0,1,0,1}. This is in contrast with the f 0,0,1,1,0,0,1,1}
assignment in Figure 3B for the conventional hierarchical modulation. Layered demodulation first FEC-decodes the upper layer symbols with a quasi-error free (QEF) performance, then uses the QEF symbols to extract the lower layer signal.
Therefore, no errors are introduced by uncoded lower layer symbol errors. The delay memory required to obtain the QEF upper layer symbols for this application presents a small additional receiver cost, particularly in consideration of the ever-decreasing solid state memory cost over time.
assignment in Figure 3B for the conventional hierarchical modulation. Layered demodulation first FEC-decodes the upper layer symbols with a quasi-error free (QEF) performance, then uses the QEF symbols to extract the lower layer signal.
Therefore, no errors are introduced by uncoded lower layer symbol errors. The delay memory required to obtain the QEF upper layer symbols for this application presents a small additional receiver cost, particularly in consideration of the ever-decreasing solid state memory cost over time.
[0065] In a conventional hierarchical receiver using non-uniform 8PSK, the LP
signal performance can be impacted by HP demodulator performance. The demodulator normally includes a timing and Garner recovery loop. In most conventional recovery loops, a decision-directed feedback loop is included.
Uncoded symbol decisions are used in the prediction of the tracking error at each symbol time of the recovery loop. The tracking loop would pick up an error vector whenever a symbol decision is in error; the uncoded symbol error rate (SER) could be as high as 6% in many legacy systems. An FEC-corrected demodulator of this invention avoids the degradation.
signal performance can be impacted by HP demodulator performance. The demodulator normally includes a timing and Garner recovery loop. In most conventional recovery loops, a decision-directed feedback loop is included.
Uncoded symbol decisions are used in the prediction of the tracking error at each symbol time of the recovery loop. The tracking loop would pick up an error vector whenever a symbol decision is in error; the uncoded symbol error rate (SER) could be as high as 6% in many legacy systems. An FEC-corrected demodulator of this invention avoids the degradation.
[0066] FIG. 4A is a block diagram illustrating a first layered modulation system 400 S using a single transponder 402 in a satellite. The uplink signal 406 is processed at the broadcast center 408. Both the upper layer (UL) and lower layer (LL) signals 410, 412 are encoded and mapped and modulated together 414 before frequency upconversion 416. The signals 410, 412 are combined after FEC encoding. A
receiver 418 decodes the downlink from the transponder 402. Conventional single traveling wave tube amplifiers (TWTAs) are suitable for constant-envelope signal such as 8PSK and derivatives. This system is suited for layered modulation using coherent UL and LL signals.
receiver 418 decodes the downlink from the transponder 402. Conventional single traveling wave tube amplifiers (TWTAs) are suitable for constant-envelope signal such as 8PSK and derivatives. This system is suited for layered modulation using coherent UL and LL signals.
[0067] FIG. 4B is a block diagram illustrating a second layered modulation system 420 using multiple transponders 402A, 402B. The upper layer (UL) and lower layer (LL) signals 410, 412 are separately encoded and mapped and modulated 414A, before separate frequency upconversion 416A, 416B. A separate broadcast center can be used for each layer. The signals 410, 412 are combined in space before downlink. A receiver 418 decodes the downlinked signals simultaneously received from transponders 402A, 402B. Separate TWTAs for the transponders 402A, 402B
allow nonlinear TWTA outputs to be combined in space. The upper layer and lower layer signals 410, 412 can be coherent or non-coherent.
allow nonlinear TWTA outputs to be combined in space. The upper layer and lower layer signals 410, 412 can be coherent or non-coherent.
[0068] FIG. 5 is a block diagram of an exemplary receiver 500 of a layered modulation signal, similar to those described in U.S. Patent Application Serial No.
09/844,401, filed on April 27, 2001, and entitled "LAYERED MODULATION FOR
DIGITAL SIGNALS", by Ernest C. Chen. FEC re-encoding and remodulation may begin prior to the final decoding of the upper layer. In addition, processing is simplified for signals that are coherent between layers, particularly processing of the lower layer.
09/844,401, filed on April 27, 2001, and entitled "LAYERED MODULATION FOR
DIGITAL SIGNALS", by Ernest C. Chen. FEC re-encoding and remodulation may begin prior to the final decoding of the upper layer. In addition, processing is simplified for signals that are coherent between layers, particularly processing of the lower layer.
[0069] The effect of two layered modulation on channel capacity can be demonstrated by the following analysis.
N : Power of thermal noise SL : Power of lower-layer signal with Gaussian source distrib.
N~ : Effective power of upper-layer noise (N~ = SL + N) S~ : Power of upper-layer signal with Gaussian source distrib.
C~~, : Channel capacity for Conventional Modulation (bps/Hz) with the total power CLM : Channel capacity for Layered Modulation (bps/Hz) CAM =logzCl+SL+SUJ
N
CLM = logz C1 + ~ ~ + loge 1 + ~ = loge Cl + ~ ~ 1 +
U U
Since C1+~~ 1+~ =1+~+Cl+~~SS+N=1+SLNS"
U L
It follows that CLM CCM
Thus, assuming Gaussian source and noise distributions, sharing power between two layers does not reduce the total capacity of a layer modulation system.
N : Power of thermal noise SL : Power of lower-layer signal with Gaussian source distrib.
N~ : Effective power of upper-layer noise (N~ = SL + N) S~ : Power of upper-layer signal with Gaussian source distrib.
C~~, : Channel capacity for Conventional Modulation (bps/Hz) with the total power CLM : Channel capacity for Layered Modulation (bps/Hz) CAM =logzCl+SL+SUJ
N
CLM = logz C1 + ~ ~ + loge 1 + ~ = loge Cl + ~ ~ 1 +
U U
Since C1+~~ 1+~ =1+~+Cl+~~SS+N=1+SLNS"
U L
It follows that CLM CCM
Thus, assuming Gaussian source and noise distributions, sharing power between two layers does not reduce the total capacity of a layer modulation system.
[0070] The effect of an additional layer in a layered modulation system on channel capacity can also be demonstrated by the following analysis.
N : Power of thermal noise SB : Power sum of bottom 2 signals with Gaussian source distrib.
(B--__U+L; SB=SU+S~) NT : Power of top-layer noise (NT = SB + N) ST : Power of top-layer signal with Gaussian source distrib.
CAM : Channel capacity for Conventional Modulation (bps/Hz) with the total power CLM : Channel capacity for Layered Modulation (bps/Hz) CAM = loge C1 + SB + ST
N
CAM = logz C1 + ~ ~ + loge 1 + ~ = loge C1 + ~ ~ 1 +
T T
Since C1+ ~~ 1+~ =1+ ~ +C1+ ~~S S+N =1+SBNST
T a It follows that CLM - CCM
Thus, again assuming Gaussian source and noise distributions, sharing power among any number of layers does not reduce the total capacity.
N : Power of thermal noise SB : Power sum of bottom 2 signals with Gaussian source distrib.
(B--__U+L; SB=SU+S~) NT : Power of top-layer noise (NT = SB + N) ST : Power of top-layer signal with Gaussian source distrib.
CAM : Channel capacity for Conventional Modulation (bps/Hz) with the total power CLM : Channel capacity for Layered Modulation (bps/Hz) CAM = loge C1 + SB + ST
N
CAM = logz C1 + ~ ~ + loge 1 + ~ = loge C1 + ~ ~ 1 +
T T
Since C1+ ~~ 1+~ =1+ ~ +C1+ ~~S S+N =1+SBNST
T a It follows that CLM - CCM
Thus, again assuming Gaussian source and noise distributions, sharing power among any number of layers does not reduce the total capacity.
[0071] FIG. 6 is a example plot illustrating channel capacity shared between upper and lower layers. This example is for a 11.76 dB total signal power (referenced to thermal noise). The power is shared between upper and lower layer signals. A
Gaussian source distribution is assumed for both layers as well as a Gaussian noise distribution. Channel capacity is approximately 4 bps/Hz for CNR of 11.76 dB.
As shown, the sum of the two layer capacities always equals the total capacity.
Gaussian source distribution is assumed for both layers as well as a Gaussian noise distribution. Channel capacity is approximately 4 bps/Hz for CNR of 11.76 dB.
As shown, the sum of the two layer capacities always equals the total capacity.
[0072] Hierarchical 8PSK can be viewed as a special case of layered modulation.
Referring to FIG. 3B, constant power can be applied for all signals. The high priority (HP) data signal, represented by the nodes 302A-302D corresponds to the upper layer.
The low priority (LP) signal, represented by the nodes 304A-304D and 304A'-304D', corresponds to the lower layer. The HP and LP signals are synchronous, having n , i.
ii::;rr g"",, "~i~ ,. .; ~' ii li rf~ ::: fl"'ii "°a! .; .:.at t~ "ii fi:::ii ii..it,.'".:it' ::::.it fi""~t ii "H a".:ii :;"a; i~ "it i'c "1i li.s..
a ..",.~ n .~~ n."r "."n n,..u ,.",u .,~ u.".. o..,u n...o- n .,~~ m n,.".
n,~.u n...u ..~~~ a,~.., n..... n.,.u n coherent phase and identical baud timing. The HP layer of an 8PSK
hierarchically modulated signal can be demodulated as if the composite signal were QPSK, typically using a decision-direct feedback tracking loop.
[0001] FIGS. 7 & 8 are block diagrams of exemplary receivers for hierarchical modulation similar to those described in PCT Patent Application No.
PCT/LTS03/20862, filed on July l, 2003, and entitled "IMPROVING
HIERARCHICAL 8PSK PERFORMANCE°', by Ernest C. Chen et al.
LAYERED AND HIERARCHICAL SIMULATION
a~~#i . [0002] Embodiments of the invention comprise systems and methods for simulating a layer-modulated signal, including a hierarchically modulated signal. The methods and systems presented herein can be used to accelerate the study and development of layered modulation systems while reducing costs. Many different proposed layered modulation implementations can be quickly and inexpensively evaluated.
[0003] In one exemplary embodiment an end-to-end simulation of communication channel, including satellite distortions, downlink noise, receiver phase noise and receiver implementation errors is developed. The simulator can be developed using a mathematical programming tool such as MATLAB. Standard signals can incorporated into the simulator for ready application, e.g. DIRECTV and DVB-S
signals as well as turbo codes and other signals.
[0004] The simulator can be used to process computer-simulated signals or data captured from modulators and/or satellites. For example, LM signals can be emulated by RF-combining real-time signals. In addition, cross-check laboratory tests can be performed with synthesized signal performance. A field programmable gate array (FPGA) LM signal processor essentially mimics a LM simulator of the invention, but with real time processing.
p~ s~~~r [0077] FIG. 9 is a block diagram of a complete simulation 900 of a layer modulated signal. Pseudorandom binary sequence (PRBS) generators 902, 904 are used to create the upper and lower layer data. Data from each layer is then passed through an forward error correction (FEC) encoder 906, 908. After FEC encoding the signals can be processed to simulate either a single or dual-transponder system. See FIGS.
and 4B. If a dual-transponder system is being simulated (as in FIG. 4B), the upper and lower layers are processed separately. Each signal layer is separately passed through a signal mapper 910A, 910B, a pulse shaping filter 912A, 912B (e.g., a root raised cosine filter), a baud timing and Garner frequency offset simulator 914A, 914B, and a satellite distortion simulator 916A, 916B. If a single transponder system is being simulated (as in FIG. 4A), the upper and lower layers are combined and passed through the same set of processes together with a weighted summation contained in signal mapper 910. For a dual-transponder system, the upper and lower layers are combined at the output in a weighted summation 918. In either case, modeled channel interference effects 920 (adjacent and co-channel) are added. The composite signal is then processed by adding white Guassian noise provided by a noise generator 922, phase noise from a phase noise generator 924 and frequency filtering by a receiver front end filter 926 before receiver processing 928. Captured data 930 from laboratory equipment that provide the same functionality as the simulation modules (902, 904...all items in Figure 9 except 930 and 928) can be applied to the receiver processing to evaluate performance.
[0078] FIG. 10 is a graphical user interface (GUI) 1000 of an exemplary layer modulated signal simulator including several blocks of FIG. 9 showing BER test results. The display outlines the simulator signal processing flow. Upper and lower layer signal transmitters 1002, 1004 are shown with signal outputs combined and passed through the additive white Gaussian noise (AWGI~ channel 1006. The composite signal then arrives at the receiver 1008. Lower layer ouputs are provided to a lower layer performance measurement block 1010 along with the original lower layer signal from the lower layer transmitter 1004. Similarly, upper layer ouputs are provided to an upper layer performance measurement block 1012 along with the original upper layer signal from the upper layer transmitter 1002. An error rate and frame based bit error calculation are performed for each layer to establish a performance measurement. Operational parameters can be set in a dialog box 1014.
S [0079] FIG. 11A is a block diagram of an exemplary system 1100 for synthesizing a layer modulated signal in a laboratory. A first modulator 1102 is used to modulate a first bit stream, e.g. a PRBS, of the upper layer to produce an upper layer signal. A
noise generator 1106 can be used to add noise to the upper layer signal. A
second modulator 1104 is used for modulating a second bit stream of a lower layer to produce a lower layer signal. An attenuator 1108, (such as variable attenuator) can be used for appropriately attenuating the lower layer signal. A combiner 1110 is then used to combining the noise-added upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal. (Equivalently, noise generator with a corresponding output power level may be placed on the lower layer path instead of the upper layer path.) The composite layer modulated signal can then be upconverted 1112 before being communicated to a tuner 1114 to extract the in-phase and quadrature components of the separate signal layers, analyzed using a scope 1116 as desired. If a digitizing oscilloscope is used, the digitized in-phase and quadrature signals can be introduced as the Captured Data 930 in Figure 9. Directional couplers 1118, 1120 can be used to tap the upper layer signal (prior to noise addition) and the lower layer signal (after attenuation) to be used in evaluating the relative power levels of the upper and lower layer signals prior to the addition by the combiner 1110..
Similarly, the composite signal can also be tapped by a direction coupler 1122.
[0080] FIG. 11B is a block diagram of an exemplary system 1150 for simulating a layer modulated signal using satellite signals. Distinct satellite signals 1152, 1154 are received at separate antennas 1156, 1158. It is important to note that the two received signals 1152, 1154 are not layered modulation signals. Both signals 1152, 1154 are passed through separate amplifiers 1160, 1162. The satellite signal 1154 to be used as the lower layer signal is passed through an attenuator 1164 (such as a variable attenuator) to appropriately attenuate the signal. Both signals are then combined at the combiner 1166 to form the composite layered modulation signal. The composite signal can then be communicated to a tuner 1168 to extract the in-phase and S quadrature components of the separate signal layers which may be analyzed using a scope 1176. If a digitizing oscilloscope is used, the digitized in-phase and quadrature signals can be introduced as the Captured Data 930 in Figure 9. Directional couplers 1170, 1172, 1174 can be used to tap the upper layer signal, lower layer signal and the composite signal, respectively. These tapped signal are used to evaluate the signal and/or attenuator performance. This system 1150 requires less expensive equipment than the embodiment of FIG. 11 A (particularly, omitting the modulators 1102, 1104).
In addition, because actual satellite signals 1152, 1154 are used, real signal effects are included in the composite layer modulated signal.
[0081] FIG. 12 is flowchart of an exemplary method 1200 for simulating a layer modulated signal. The method applies to the systems of both FIGS. 11A & 11B.
The method 1200 simulates a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer. At step 1202 an upper layer signal is provided comprising a first modulated bit stream. At step 1204, a lower layer signal is provided comprising a second modulated bit stream. Next at step 1206, the lower layer signal is attenuated. Finally at step 1208, the upper layer signal and the attenuated lower layer signal are combined to produce the composite layer modulated signal. The method can be further modified consistent with the foregoing system embodiments.
[0082] FIG. 13 is a flowchart of processing for a layer modulated signal.
Further detail of layered modulation processing can be found U.S. Patent Application Serial No. 09/844,401, filed on April 27, 2001, and entitled "LAYERED MODULATION
FOR DIGITAL SIGNALS", by Ernest C. Chen. Layered modulation simulation methods and systems of the invention can be used to evaluate the performance of layered signals as well as receiver processes.
EXEMPLARY LAYERED MODULATION SIMULATION
[0083] An exemplary computer simulation of a layered modulation signal can be defined with the following parameters. Both layers can use a nominal symbol frequency of 20 MHz (not necessarily synchronized to each other in timing frequency and phase). The carrier frequencies are not necessarily coherent with respect to each other either. The excess bandwidth ratio is 0.2. It is assumed that no satellite degradation of the signal occurs; TWTA and filter effects can be modeled separately if necessary. The upper and lower layer signals can each be a convolutional code 6/7, Reed-Soloman (146, 130) signal with an assigned reference power of 0 dB to the upper layer. Upper layer CNR is approximately 7.7 dB. Lower layer CNR is approximately 7.6 dB. Noise (AWGN) of -16 dB can be applied. A turbo-coded signal may alternately be used for the lower layer. Phase noise of the low noise block (LNB) and tuner are included. The following table summarizes the simulation results.
In ut C NR dB Out ut CNR dB
UL LL UL LL Dynamic Range 7.6 None 7.43 None 7.43 7.7 7.6 7.51 7.22 ~ 15.48 The first row applies to processing only the upper layer, which reduces CNR by approximately 0.2 dB (7.6 dB - 7.43 dB). The second row applies to processing both layers. The lower layer CNR is reduced by approximately 0.4 dB (7.6 dB - 7.22 dB).
This result compares favorably with nominal 16QAM performance. Further details of the simulation process are shown hereafter.
[0084] FIG. 14 is power spectrum plot of an exemplary layer modulated signal that can be simulated by the method and system previously described. The composite upper and lower layer signals are added with thermal noise. A sampling frequency of 100 MHz is used and a display resolution of 1 MHz is shown. The spectrum peak is scaled to 0 dB, showing a thermal noise floor of approximately -17 dB. A front end receiver filter is used to taper the noise floor.
[0085] FIGS. 15A-15C are plots illustrating upper layer symbol timing recovery for S an exemplary layer modulated signal. FIG. 15A is a plot of the comparator output, based on a zero-crossing method. FIG. 15B is the low pass filter (LPF) output of the loop filter; a decision-directed second order filter is applied. A nominal baud rate of 20 MHz is recovered. FIG. 15C is a plot of the tracked symbol times (indicating a delta baud rate) with a fitted curve overlaid. A small RMS error is exhibited.
(0086] FIGS. 15D-15F are plots illustrating an upper layer symbol timing recovered signal for an exemplary layer modulated signal. FIGS. 15D and 15E illustrate respectively the upper layer signal before and after the timing recovery loop.
FIG. 15F
is a plot of the CNR estimate after the timing recovery loop. The estimated output CNR of 7.78 dB, which includes measurement errors, compares very favorably with the input CNR of 7.7 dB.
[0087] FIGS. 16A-16C are plots illustrating upper layer Garner recovery for an exemplary layer modulated signal. FIG. 16A is a plot of the phase comparator output, based on quadrature multiplication. FIG. 16B is a plot of the loop LPF output, using a decision-directed second order scheme. A baud rate of approximately 20 MHz is recovered. FIG. 16C is a plot of the phase tracked out for the simulated Garner frequency and phase noise. A small RMS error in phase is exhibited.
[0088] FIGS. 16D-16F are plots illustrating an upper layer carrier recovered signal for an exemplary layer modulated signal. FIG. 16D illustrates the upper layer signal before the carrier recovery loop. FIG. 16E illustrates the upper layer signal after the Garner recovery loop when the signal constellation is stabilized; the upper layer QPSK
signal in the presence of the lower layer QPSK and noise are apparent. FIG.
16F is a histogram of the phase error about a constellation node. The estimated output CNR of 7.51 dB compares well with the input CNR of 7.7 dB.
[0089] FIG. 17A is a plot of uncoded upper layer bit errors at the demodulator output for an exemplary layer modulated signal. The errors at the Garner recovery loop output are shown. The plot identifies 80 R-S packets of data by the "packet"
number versus the two-bit symbol number. The plot reports approximately 0.16%
of BER at an estimated CNR of 7.5 dB.
[0090] FIG. 17B is a plot of upper layer byte errors at the Viterbi decoder output for an exemplary layer modulated signal. The packet number is displayed versus an eight-bit symbol number, showing 95 packets worth of data. A BER of 0.282% is reported.
[0091] FIG. 17C is a plot of upper layer byte errors at the de-interleaver output for an exemplary layer modulated signal. The packet number is displayed versus an eight-bit symbol number, showing 83 packets worth of data. [0092] FIG. 17D is a plot of upper layer errors correctable by a Reed-Solomon decoder for an exemplary layer modulated signal. Of the 83 packets worth of data, only 3 packets with one R-S
correctable error byte each occurred, which is well below the correction threshold of eight errors. Thus, no uncorrectable errors were exhibited in 83 packets at an estimated CNR of 7.5 dB.
[0093] FIG. 18 is a plot of upper layer signal matching calculated between received signal and reconstructed signal for an exemplary layer modulated signal. As shown, nearly constant matching coefficients (in magnitude and phase) are exhibited over 300,000 100-MHz samples, despite the presence of the lower layer signal.
[0094] FIG. 19 is power spectrum plot of an extracted lower layer signal of an exemplary layer modulated signal. A sampling frequency of 100 MHz is used and a display resolution is 1 MHz. The spectrum peak is scaled to 0 dB with a thermal noise floor of approximately -9 dB after canceling out the upper layer signal.
The plot can be compared with the power spectrum of the composite signal shown in FIG.
14.
[0095] FIGS. 20A-20C are plots illustrating the extracted lower layer symbol timing recovery for an exemplary layer modulated signal. FIG. 20A is a plot of a lower layer comparator output, based on a zero-crossing method. FIG. 20B is the loop low pass filter (LPF) output; a decision-directed second order filter is applied. A
nominal baud rate of 20 MHz is extracted. FIG. 20C is a plot of the tracked symbol times (indicating a delta baud rate) with a fitted curve overlaid. A small RMS error is exhibited.
[0096] FIGS. 20D-20F are plots illustrating a lower layer symbol timing recovered signal for an exemplary layer modulated signal. FIGS. 20D and 20E illustrate respectively the upper layer signal before and after the timing recovery loop.
The lower layer forms a ring in signal constellation. FIG. 20F is a plot of the CNR
estimate after the timing recovery loop. The estimated output CNR of 7.22 dB
compares well with the input CNR of 7.6 dB.
(0097] FIGS. 21A-21C are plots illustrating lower layer carrier recovery for an exemplary layer modulated signal. FIG. 21A is a plot of the lower layer phase comparator output, based on quadrature multiplication. FIG. 21B is a plot of the loop LPF output, using a decision-directed second order scheme. A nominal baud rate of 20 MHz is extracted. FIG. 21 C is a plot of the phase tracked out for the simulated carrier frequency and phase noise. A nominal RMS error in phase is exhibited.
[0098] FIGS. 21D-21F are plots illustrating an lower layer carrier recovered signal for an exemplary layer modulated signal. FIG. 21D illustrates the upper layer signal before the carrier recovery loop. FIG. 21E illustrates the upper layer signal after the carrier recovery loop when the signal constellation is stabilized; the lower layer QPSK
signal in the presence of noise are apparent. FIG. 21F is a histogram of the phase error about a constellation node. The estimated output CNR of 7.22 dB compares reasonably well with the input CNR of 7.6 dB.
[0099] FIG. 22A is a plot of uncoded lower layer bit errors at the demodulator output for an exemplary layer modulated signal. The errors at the carrier recovery S loop output are shown. The plot identifies 80 R-S packets of data by the "packet"
number versus the two-bit symbol number. The plot reports approximately 1.1 %
of BER at an estimated CNR of 7.2 dB.
[0100] FIG. 22B is a plot of lower layer byte errors at the Viterbi decoder output for an exemplary layer modulated signal. The packet number is displayed versus an eight-bit symbol number, showing 95 packets worth of data. A BER of 0.297% is reported.
[0101] FIG. 22C is a plot of lower layer byte errors at the De-interleaver output for an exemplary layer modulated signal. The packet number is displayed versus an eight-bit symbol number, showing 83 packets worth of data.
(0102] FIG. 22D is a plot of upper layer errors correctable by a Reed-Solomon decoder for an exemplary layer modulated signal. Of the 83 packets worth of data, onlyl 1 packets with one R-S correctable error byte each occurred, which is well below the correction threshold of eight errors. Thus, no uncorrectable errors were exhibited in 83 packets at an estimated CNR of 7.2 dB.
[0103] FIG. 23A is a plot of uncoded bit error rates for upper and lower layers of an exemplary layer modulated signal. The plot identifies the lower layer and upper layer simulation results relative to a theoretical result based on additive white gaussian noise (AWGN) curve, illustrating the result of 65K samples (130K bits) of data. The lower layer at the estimated CNR is shown with a BER right on the AWGN curve.
The upper layer shows a BER below the curve equaling a 2.1 dB increase. Thus, QPSK interference is more benign than AWGN of the same power.
[0104] FIG. 23B is a plot of Viterbi decoder output bit error rates for upper and lower layers of an exemplary layer modulated signal. The plot identifies the lower layer and upper layer simulation results relative to the AWGN curve, illustrating the result of 65K samples (130K bits) of data. In this case, the estimated CNR and BER
for both upper and lower layers occur close to the AWGN curve.
[0105] 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.
Referring to FIG. 3B, constant power can be applied for all signals. The high priority (HP) data signal, represented by the nodes 302A-302D corresponds to the upper layer.
The low priority (LP) signal, represented by the nodes 304A-304D and 304A'-304D', corresponds to the lower layer. The HP and LP signals are synchronous, having n , i.
ii::;rr g"",, "~i~ ,. .; ~' ii li rf~ ::: fl"'ii "°a! .; .:.at t~ "ii fi:::ii ii..it,.'".:it' ::::.it fi""~t ii "H a".:ii :;"a; i~ "it i'c "1i li.s..
a ..",.~ n .~~ n."r "."n n,..u ,.",u .,~ u.".. o..,u n...o- n .,~~ m n,.".
n,~.u n...u ..~~~ a,~.., n..... n.,.u n coherent phase and identical baud timing. The HP layer of an 8PSK
hierarchically modulated signal can be demodulated as if the composite signal were QPSK, typically using a decision-direct feedback tracking loop.
[0001] FIGS. 7 & 8 are block diagrams of exemplary receivers for hierarchical modulation similar to those described in PCT Patent Application No.
PCT/LTS03/20862, filed on July l, 2003, and entitled "IMPROVING
HIERARCHICAL 8PSK PERFORMANCE°', by Ernest C. Chen et al.
LAYERED AND HIERARCHICAL SIMULATION
a~~#i . [0002] Embodiments of the invention comprise systems and methods for simulating a layer-modulated signal, including a hierarchically modulated signal. The methods and systems presented herein can be used to accelerate the study and development of layered modulation systems while reducing costs. Many different proposed layered modulation implementations can be quickly and inexpensively evaluated.
[0003] In one exemplary embodiment an end-to-end simulation of communication channel, including satellite distortions, downlink noise, receiver phase noise and receiver implementation errors is developed. The simulator can be developed using a mathematical programming tool such as MATLAB. Standard signals can incorporated into the simulator for ready application, e.g. DIRECTV and DVB-S
signals as well as turbo codes and other signals.
[0004] The simulator can be used to process computer-simulated signals or data captured from modulators and/or satellites. For example, LM signals can be emulated by RF-combining real-time signals. In addition, cross-check laboratory tests can be performed with synthesized signal performance. A field programmable gate array (FPGA) LM signal processor essentially mimics a LM simulator of the invention, but with real time processing.
p~ s~~~r [0077] FIG. 9 is a block diagram of a complete simulation 900 of a layer modulated signal. Pseudorandom binary sequence (PRBS) generators 902, 904 are used to create the upper and lower layer data. Data from each layer is then passed through an forward error correction (FEC) encoder 906, 908. After FEC encoding the signals can be processed to simulate either a single or dual-transponder system. See FIGS.
and 4B. If a dual-transponder system is being simulated (as in FIG. 4B), the upper and lower layers are processed separately. Each signal layer is separately passed through a signal mapper 910A, 910B, a pulse shaping filter 912A, 912B (e.g., a root raised cosine filter), a baud timing and Garner frequency offset simulator 914A, 914B, and a satellite distortion simulator 916A, 916B. If a single transponder system is being simulated (as in FIG. 4A), the upper and lower layers are combined and passed through the same set of processes together with a weighted summation contained in signal mapper 910. For a dual-transponder system, the upper and lower layers are combined at the output in a weighted summation 918. In either case, modeled channel interference effects 920 (adjacent and co-channel) are added. The composite signal is then processed by adding white Guassian noise provided by a noise generator 922, phase noise from a phase noise generator 924 and frequency filtering by a receiver front end filter 926 before receiver processing 928. Captured data 930 from laboratory equipment that provide the same functionality as the simulation modules (902, 904...all items in Figure 9 except 930 and 928) can be applied to the receiver processing to evaluate performance.
[0078] FIG. 10 is a graphical user interface (GUI) 1000 of an exemplary layer modulated signal simulator including several blocks of FIG. 9 showing BER test results. The display outlines the simulator signal processing flow. Upper and lower layer signal transmitters 1002, 1004 are shown with signal outputs combined and passed through the additive white Gaussian noise (AWGI~ channel 1006. The composite signal then arrives at the receiver 1008. Lower layer ouputs are provided to a lower layer performance measurement block 1010 along with the original lower layer signal from the lower layer transmitter 1004. Similarly, upper layer ouputs are provided to an upper layer performance measurement block 1012 along with the original upper layer signal from the upper layer transmitter 1002. An error rate and frame based bit error calculation are performed for each layer to establish a performance measurement. Operational parameters can be set in a dialog box 1014.
S [0079] FIG. 11A is a block diagram of an exemplary system 1100 for synthesizing a layer modulated signal in a laboratory. A first modulator 1102 is used to modulate a first bit stream, e.g. a PRBS, of the upper layer to produce an upper layer signal. A
noise generator 1106 can be used to add noise to the upper layer signal. A
second modulator 1104 is used for modulating a second bit stream of a lower layer to produce a lower layer signal. An attenuator 1108, (such as variable attenuator) can be used for appropriately attenuating the lower layer signal. A combiner 1110 is then used to combining the noise-added upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal. (Equivalently, noise generator with a corresponding output power level may be placed on the lower layer path instead of the upper layer path.) The composite layer modulated signal can then be upconverted 1112 before being communicated to a tuner 1114 to extract the in-phase and quadrature components of the separate signal layers, analyzed using a scope 1116 as desired. If a digitizing oscilloscope is used, the digitized in-phase and quadrature signals can be introduced as the Captured Data 930 in Figure 9. Directional couplers 1118, 1120 can be used to tap the upper layer signal (prior to noise addition) and the lower layer signal (after attenuation) to be used in evaluating the relative power levels of the upper and lower layer signals prior to the addition by the combiner 1110..
Similarly, the composite signal can also be tapped by a direction coupler 1122.
[0080] FIG. 11B is a block diagram of an exemplary system 1150 for simulating a layer modulated signal using satellite signals. Distinct satellite signals 1152, 1154 are received at separate antennas 1156, 1158. It is important to note that the two received signals 1152, 1154 are not layered modulation signals. Both signals 1152, 1154 are passed through separate amplifiers 1160, 1162. The satellite signal 1154 to be used as the lower layer signal is passed through an attenuator 1164 (such as a variable attenuator) to appropriately attenuate the signal. Both signals are then combined at the combiner 1166 to form the composite layered modulation signal. The composite signal can then be communicated to a tuner 1168 to extract the in-phase and S quadrature components of the separate signal layers which may be analyzed using a scope 1176. If a digitizing oscilloscope is used, the digitized in-phase and quadrature signals can be introduced as the Captured Data 930 in Figure 9. Directional couplers 1170, 1172, 1174 can be used to tap the upper layer signal, lower layer signal and the composite signal, respectively. These tapped signal are used to evaluate the signal and/or attenuator performance. This system 1150 requires less expensive equipment than the embodiment of FIG. 11 A (particularly, omitting the modulators 1102, 1104).
In addition, because actual satellite signals 1152, 1154 are used, real signal effects are included in the composite layer modulated signal.
[0081] FIG. 12 is flowchart of an exemplary method 1200 for simulating a layer modulated signal. The method applies to the systems of both FIGS. 11A & 11B.
The method 1200 simulates a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer. At step 1202 an upper layer signal is provided comprising a first modulated bit stream. At step 1204, a lower layer signal is provided comprising a second modulated bit stream. Next at step 1206, the lower layer signal is attenuated. Finally at step 1208, the upper layer signal and the attenuated lower layer signal are combined to produce the composite layer modulated signal. The method can be further modified consistent with the foregoing system embodiments.
[0082] FIG. 13 is a flowchart of processing for a layer modulated signal.
Further detail of layered modulation processing can be found U.S. Patent Application Serial No. 09/844,401, filed on April 27, 2001, and entitled "LAYERED MODULATION
FOR DIGITAL SIGNALS", by Ernest C. Chen. Layered modulation simulation methods and systems of the invention can be used to evaluate the performance of layered signals as well as receiver processes.
EXEMPLARY LAYERED MODULATION SIMULATION
[0083] An exemplary computer simulation of a layered modulation signal can be defined with the following parameters. Both layers can use a nominal symbol frequency of 20 MHz (not necessarily synchronized to each other in timing frequency and phase). The carrier frequencies are not necessarily coherent with respect to each other either. The excess bandwidth ratio is 0.2. It is assumed that no satellite degradation of the signal occurs; TWTA and filter effects can be modeled separately if necessary. The upper and lower layer signals can each be a convolutional code 6/7, Reed-Soloman (146, 130) signal with an assigned reference power of 0 dB to the upper layer. Upper layer CNR is approximately 7.7 dB. Lower layer CNR is approximately 7.6 dB. Noise (AWGN) of -16 dB can be applied. A turbo-coded signal may alternately be used for the lower layer. Phase noise of the low noise block (LNB) and tuner are included. The following table summarizes the simulation results.
In ut C NR dB Out ut CNR dB
UL LL UL LL Dynamic Range 7.6 None 7.43 None 7.43 7.7 7.6 7.51 7.22 ~ 15.48 The first row applies to processing only the upper layer, which reduces CNR by approximately 0.2 dB (7.6 dB - 7.43 dB). The second row applies to processing both layers. The lower layer CNR is reduced by approximately 0.4 dB (7.6 dB - 7.22 dB).
This result compares favorably with nominal 16QAM performance. Further details of the simulation process are shown hereafter.
[0084] FIG. 14 is power spectrum plot of an exemplary layer modulated signal that can be simulated by the method and system previously described. The composite upper and lower layer signals are added with thermal noise. A sampling frequency of 100 MHz is used and a display resolution of 1 MHz is shown. The spectrum peak is scaled to 0 dB, showing a thermal noise floor of approximately -17 dB. A front end receiver filter is used to taper the noise floor.
[0085] FIGS. 15A-15C are plots illustrating upper layer symbol timing recovery for S an exemplary layer modulated signal. FIG. 15A is a plot of the comparator output, based on a zero-crossing method. FIG. 15B is the low pass filter (LPF) output of the loop filter; a decision-directed second order filter is applied. A nominal baud rate of 20 MHz is recovered. FIG. 15C is a plot of the tracked symbol times (indicating a delta baud rate) with a fitted curve overlaid. A small RMS error is exhibited.
(0086] FIGS. 15D-15F are plots illustrating an upper layer symbol timing recovered signal for an exemplary layer modulated signal. FIGS. 15D and 15E illustrate respectively the upper layer signal before and after the timing recovery loop.
FIG. 15F
is a plot of the CNR estimate after the timing recovery loop. The estimated output CNR of 7.78 dB, which includes measurement errors, compares very favorably with the input CNR of 7.7 dB.
[0087] FIGS. 16A-16C are plots illustrating upper layer Garner recovery for an exemplary layer modulated signal. FIG. 16A is a plot of the phase comparator output, based on quadrature multiplication. FIG. 16B is a plot of the loop LPF output, using a decision-directed second order scheme. A baud rate of approximately 20 MHz is recovered. FIG. 16C is a plot of the phase tracked out for the simulated Garner frequency and phase noise. A small RMS error in phase is exhibited.
[0088] FIGS. 16D-16F are plots illustrating an upper layer carrier recovered signal for an exemplary layer modulated signal. FIG. 16D illustrates the upper layer signal before the carrier recovery loop. FIG. 16E illustrates the upper layer signal after the Garner recovery loop when the signal constellation is stabilized; the upper layer QPSK
signal in the presence of the lower layer QPSK and noise are apparent. FIG.
16F is a histogram of the phase error about a constellation node. The estimated output CNR of 7.51 dB compares well with the input CNR of 7.7 dB.
[0089] FIG. 17A is a plot of uncoded upper layer bit errors at the demodulator output for an exemplary layer modulated signal. The errors at the Garner recovery loop output are shown. The plot identifies 80 R-S packets of data by the "packet"
number versus the two-bit symbol number. The plot reports approximately 0.16%
of BER at an estimated CNR of 7.5 dB.
[0090] FIG. 17B is a plot of upper layer byte errors at the Viterbi decoder output for an exemplary layer modulated signal. The packet number is displayed versus an eight-bit symbol number, showing 95 packets worth of data. A BER of 0.282% is reported.
[0091] FIG. 17C is a plot of upper layer byte errors at the de-interleaver output for an exemplary layer modulated signal. The packet number is displayed versus an eight-bit symbol number, showing 83 packets worth of data. [0092] FIG. 17D is a plot of upper layer errors correctable by a Reed-Solomon decoder for an exemplary layer modulated signal. Of the 83 packets worth of data, only 3 packets with one R-S
correctable error byte each occurred, which is well below the correction threshold of eight errors. Thus, no uncorrectable errors were exhibited in 83 packets at an estimated CNR of 7.5 dB.
[0093] FIG. 18 is a plot of upper layer signal matching calculated between received signal and reconstructed signal for an exemplary layer modulated signal. As shown, nearly constant matching coefficients (in magnitude and phase) are exhibited over 300,000 100-MHz samples, despite the presence of the lower layer signal.
[0094] FIG. 19 is power spectrum plot of an extracted lower layer signal of an exemplary layer modulated signal. A sampling frequency of 100 MHz is used and a display resolution is 1 MHz. The spectrum peak is scaled to 0 dB with a thermal noise floor of approximately -9 dB after canceling out the upper layer signal.
The plot can be compared with the power spectrum of the composite signal shown in FIG.
14.
[0095] FIGS. 20A-20C are plots illustrating the extracted lower layer symbol timing recovery for an exemplary layer modulated signal. FIG. 20A is a plot of a lower layer comparator output, based on a zero-crossing method. FIG. 20B is the loop low pass filter (LPF) output; a decision-directed second order filter is applied. A
nominal baud rate of 20 MHz is extracted. FIG. 20C is a plot of the tracked symbol times (indicating a delta baud rate) with a fitted curve overlaid. A small RMS error is exhibited.
[0096] FIGS. 20D-20F are plots illustrating a lower layer symbol timing recovered signal for an exemplary layer modulated signal. FIGS. 20D and 20E illustrate respectively the upper layer signal before and after the timing recovery loop.
The lower layer forms a ring in signal constellation. FIG. 20F is a plot of the CNR
estimate after the timing recovery loop. The estimated output CNR of 7.22 dB
compares well with the input CNR of 7.6 dB.
(0097] FIGS. 21A-21C are plots illustrating lower layer carrier recovery for an exemplary layer modulated signal. FIG. 21A is a plot of the lower layer phase comparator output, based on quadrature multiplication. FIG. 21B is a plot of the loop LPF output, using a decision-directed second order scheme. A nominal baud rate of 20 MHz is extracted. FIG. 21 C is a plot of the phase tracked out for the simulated carrier frequency and phase noise. A nominal RMS error in phase is exhibited.
[0098] FIGS. 21D-21F are plots illustrating an lower layer carrier recovered signal for an exemplary layer modulated signal. FIG. 21D illustrates the upper layer signal before the carrier recovery loop. FIG. 21E illustrates the upper layer signal after the carrier recovery loop when the signal constellation is stabilized; the lower layer QPSK
signal in the presence of noise are apparent. FIG. 21F is a histogram of the phase error about a constellation node. The estimated output CNR of 7.22 dB compares reasonably well with the input CNR of 7.6 dB.
[0099] FIG. 22A is a plot of uncoded lower layer bit errors at the demodulator output for an exemplary layer modulated signal. The errors at the carrier recovery S loop output are shown. The plot identifies 80 R-S packets of data by the "packet"
number versus the two-bit symbol number. The plot reports approximately 1.1 %
of BER at an estimated CNR of 7.2 dB.
[0100] FIG. 22B is a plot of lower layer byte errors at the Viterbi decoder output for an exemplary layer modulated signal. The packet number is displayed versus an eight-bit symbol number, showing 95 packets worth of data. A BER of 0.297% is reported.
[0101] FIG. 22C is a plot of lower layer byte errors at the De-interleaver output for an exemplary layer modulated signal. The packet number is displayed versus an eight-bit symbol number, showing 83 packets worth of data.
(0102] FIG. 22D is a plot of upper layer errors correctable by a Reed-Solomon decoder for an exemplary layer modulated signal. Of the 83 packets worth of data, onlyl 1 packets with one R-S correctable error byte each occurred, which is well below the correction threshold of eight errors. Thus, no uncorrectable errors were exhibited in 83 packets at an estimated CNR of 7.2 dB.
[0103] FIG. 23A is a plot of uncoded bit error rates for upper and lower layers of an exemplary layer modulated signal. The plot identifies the lower layer and upper layer simulation results relative to a theoretical result based on additive white gaussian noise (AWGN) curve, illustrating the result of 65K samples (130K bits) of data. The lower layer at the estimated CNR is shown with a BER right on the AWGN curve.
The upper layer shows a BER below the curve equaling a 2.1 dB increase. Thus, QPSK interference is more benign than AWGN of the same power.
[0104] FIG. 23B is a plot of Viterbi decoder output bit error rates for upper and lower layers of an exemplary layer modulated signal. The plot identifies the lower layer and upper layer simulation results relative to the AWGN curve, illustrating the result of 65K samples (130K bits) of data. In this case, the estimated CNR and BER
for both upper and lower layers occur close to the AWGN curve.
[0105] 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.
Claims (29)
1. A method for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprising the steps of:
providing an upper layer signal comprising a first modulated bit stream;
providing a lower layer signal comprising a second modulated bit stream;
attenuating the lower layer signal; and combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal;
wherein at least one directional coupler is used to tap the composite layer modulated signal.
providing an upper layer signal comprising a first modulated bit stream;
providing a lower layer signal comprising a second modulated bit stream;
attenuating the lower layer signal; and combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal;
wherein at least one directional coupler is used to tap the composite layer modulated signal.
2. The method of claim 1, further comprising:
adding noise to the upper layer signal; and upconverting the composite layer modulated signal;
wherein providing the upper layer signal comprises modulating the first bit stream and providing the lower layer signal comprises modulating the second bit stream.
adding noise to the upper layer signal; and upconverting the composite layer modulated signal;
wherein providing the upper layer signal comprises modulating the first bit stream and providing the lower layer signal comprises modulating the second bit stream.
3. The method of claim 1, further comprising:
amplifying the upper layer signal; and amplifying the lower layer signal;
wherein providing the upper layer signal comprises receiving the first modulated bit stream from a first satellite transponder and providing the lower layer signal comprises receiving the second modulated bit stream from a second satellite transponder.
amplifying the upper layer signal; and amplifying the lower layer signal;
wherein providing the upper layer signal comprises receiving the first modulated bit stream from a first satellite transponder and providing the lower layer signal comprises receiving the second modulated bit stream from a second satellite transponder.
4. The method of claim 1, wherein at least one directional coupler is used to tap the upper layer signal.
5. The method of claim 1, wherein at least one directional coupler is used to tap the attenuated lower layer signal.
6. The method of any of claims 1 - 5, further comprising tuning the composite layer modulated signal.
7. The method of claim 6, further comprising evaluating the composite layer modulated signal performance based upon the in-phase and quadrature components of the layer modulated signal.
8. A signal simulator for performing the method of any of claims 1, 2 and 4 - 7, comprising:
a first modulator for modulating a bit stream of the upper layer to produce an upper layer signal;
a noise generator for adding noise to the upper layer signal;
a second modulator for modulating a bit stream of a lower layer to produce a lower layer signal;
an attenuator for attenuating the lower layer signal; and a combiner for combining the noise-added upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal.
a first modulator for modulating a bit stream of the upper layer to produce an upper layer signal;
a noise generator for adding noise to the upper layer signal;
a second modulator for modulating a bit stream of a lower layer to produce a lower layer signal;
an attenuator for attenuating the lower layer signal; and a combiner for combining the noise-added upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal.
9. The receiver system of claim 8, wherein the attenuator comprises a variable attenuator.
10. The receiver system of any of claims 8 or 9, further comprising an upconverter for upconverting the composite layer modulated signal.
11. The receiver system of any of claims 8 - 10, further comprising an upconverter for upconverting the composite layer modulated signal.
12. The receiver system of any of claims 8 - 11, further comprising a tuner for tuning the composite layer modulated signal.
13. A receiver system for performing the method of any of claims 1 and 3 -7, comprising:
a first antenna for receiving the upper layer signal from a first satellite transponder;
a first amplifier for amplifying the received upper layer signal;
a second antenna for receiving the lower layer signal from a second satellite transponder;
a second amplifier for amplifying the received lower layer signal;
an attenuator for attenuating the received lower layer signal; and a combiner for combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal.
a first antenna for receiving the upper layer signal from a first satellite transponder;
a first amplifier for amplifying the received upper layer signal;
a second antenna for receiving the lower layer signal from a second satellite transponder;
a second amplifier for amplifying the received lower layer signal;
an attenuator for attenuating the received lower layer signal; and a combiner for combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal.
14. The receiver system of claim 13, wherein the attenuator comprises a variable attenuator.
15. The receiver system of any of claims 13 or 14, further comprising a tuner for tuning the composite layer modulated signal.
16. A method for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprising the steps of:
providing an upper layer signal comprising a first modulated bit stream;
providing a lower layer signal comprising a second modulated bit stream;
attenuating the lower layer signal; and combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal;
tuning the composite layer modulated signal;
evaluating the composite layer modulated signal performance based upon the in-phase and quadrature components of the layer modulated signal.
providing an upper layer signal comprising a first modulated bit stream;
providing a lower layer signal comprising a second modulated bit stream;
attenuating the lower layer signal; and combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal;
tuning the composite layer modulated signal;
evaluating the composite layer modulated signal performance based upon the in-phase and quadrature components of the layer modulated signal.
17. The method of claim 16, further comprising:
adding noise to the upper layer signal; and upconverting the composite layer modulated signal;
wherein providing the upper layer signal comprises modulating the first bit stream and providing the lower layer signal comprises modulating the second bit stream.
adding noise to the upper layer signal; and upconverting the composite layer modulated signal;
wherein providing the upper layer signal comprises modulating the first bit stream and providing the lower layer signal comprises modulating the second bit stream.
18. The method of claim 16, further comprising amplifying the upper layer signal; and amplifying the lower layer signal;
wherein providing the upper layer signal comprises receiving the first modulated bit stream from a first satellite transponder and providing the lower layer signal comprises receiving the second modulated bit stream from a second satellite transponder.
wherein providing the upper layer signal comprises receiving the first modulated bit stream from a first satellite transponder and providing the lower layer signal comprises receiving the second modulated bit stream from a second satellite transponder.
19. The method of claim 16, wherein at least one directional coupler is used to tap the upper layer signal.
20. The method of claim 16, wherein at least one directional coupler is used to tap the attenuated lower layer signal.
21. The method of claim 16, wherein at least one directional coupler is used to tap the composite layer modulated signal.
22. A signal simulator for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprising:
a first modulator for modulating a bit stream of the upper layer to produce an upper layer signal;
a noise generator for adding noise to the upper layer signal;
a second modulator for modulating a bit stream of a lower layer to produce a lower layer signal;
an attenuator for attenuating the lower layer signal;
a combiner for combining the noise-added upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal;
and a directional coupler, for tapping the composite layer modulated signal.
a first modulator for modulating a bit stream of the upper layer to produce an upper layer signal;
a noise generator for adding noise to the upper layer signal;
a second modulator for modulating a bit stream of a lower layer to produce a lower layer signal;
an attenuator for attenuating the lower layer signal;
a combiner for combining the noise-added upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal;
and a directional coupler, for tapping the composite layer modulated signal.
23. The receiver system of claim 22, wherein the attenuator comprises a variable attenuator.
24. The receiver system of any of claim 22, further comprising an upconverter for upconverting the composite layer modulated signal.
25. The receiver system of any of claim 22, further comprising an upconverter for upconverting the composite layer modulated signal.
26. The receiver system of any of claim 22, further comprising a tuner for tuning the composite layer modulated signal.
27. A signal simulator for simulating a layer modulated signal having a first modulation of an upper layer and a second modulation of a lower layer, comprising:
a first antenna for receiving the upper layer signal from a first satellite transponder;
a first amplifier for amplifying the received upper layer signal;
a second antenna for receiving the lower layer signal from a second satellite transponder;
a second amplifier for amplifying the received lower layer signal;
an attenuator for attenuating the received lower layer signal; and a combiner for combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal.
a first antenna for receiving the upper layer signal from a first satellite transponder;
a first amplifier for amplifying the received upper layer signal;
a second antenna for receiving the lower layer signal from a second satellite transponder;
a second amplifier for amplifying the received lower layer signal;
an attenuator for attenuating the received lower layer signal; and a combiner for combining the upper layer signal and the attenuated lower layer signal to produce the composite layer modulated signal.
28. The receiver system of claim 27, wherein the attenuator comprises a variable attenuator.
29. The receiver system of any of claim 27, further comprising a tuner for tuning the composite layer modulated signal.
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Families Citing this family (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7423987B2 (en) | 2001-04-27 | 2008-09-09 | The Directv Group, Inc. | Feeder link configurations to support layered modulation for digital signals |
JP3899005B2 (en) * | 2002-10-03 | 2007-03-28 | 株式会社エヌ・ティ・ティ・ドコモ | Modulation apparatus, modulation method, demodulation apparatus, and demodulation method |
US8301086B2 (en) * | 2002-10-04 | 2012-10-30 | Quintic Holdings | Low-power polar transmitter |
JP4220353B2 (en) * | 2003-11-06 | 2009-02-04 | 株式会社ケンウッド | Modulation apparatus, mobile communication system, modulation method, and communication method |
US20050113040A1 (en) * | 2003-11-26 | 2005-05-26 | Walker Glenn A. | Method to minimize compatibility error in hierarchical modulation using variable phase |
US7215713B2 (en) * | 2003-11-26 | 2007-05-08 | Delphi Technologies, Inc. | Method to minimize compatibility error in hierarchical modulation |
JP4460412B2 (en) * | 2003-11-26 | 2010-05-12 | パナソニック株式会社 | Reception device and partial bit determination method |
CN1918873B (en) * | 2004-02-19 | 2010-11-03 | 汤姆森许可公司 | Method and apparatus for carrier recovery in a communications system |
US8041538B2 (en) * | 2005-07-05 | 2011-10-18 | Stmicroelectronics S.A. | Estimating of the amplitude of a noisy binary signal |
CN101558611B (en) * | 2006-04-25 | 2012-12-26 | Lg电子株式会社 | A method of configuring multiuser packet in a wireless communication system |
JP3930037B1 (en) * | 2006-04-27 | 2007-06-13 | 株式会社アドバンテスト | Test apparatus and test method |
US20080137775A1 (en) * | 2006-12-07 | 2008-06-12 | Tae Hoon Kim | Method and apparatus for hierarchical modulation and demodulation in digital broadcasting system |
US8149956B1 (en) * | 2007-04-23 | 2012-04-03 | The United States Of America As Represented By The Secretary Of The Army | Method of automated demodulation and classification of phase-shift-keying signals using hysteretic differential zero-crossing time samples |
JP5129323B2 (en) * | 2007-06-08 | 2013-01-30 | クゥアルコム・インコーポレイテッド | Hierarchical modulation on communication channels in single carrier frequency division multiple access |
KR100909280B1 (en) | 2007-06-20 | 2009-07-27 | 한국전자통신연구원 | Hierarchical Modulation Signal Reception Apparatus and Method |
US20090154387A1 (en) * | 2007-12-14 | 2009-06-18 | Sony Ericsson Mobile Communications Ab | Distributing digital video content to mobile terminals using primary and secondary communication networks |
KR100961443B1 (en) * | 2007-12-19 | 2010-06-09 | 한국전자통신연구원 | Hierarchical transmitting/receiving apparatus and method for improving availability of broadcasting service |
KR101409562B1 (en) * | 2009-10-29 | 2014-06-19 | 한국전자통신연구원 | Apparatus and method for enhancing reception performance of high power signal using low power signal |
US8379769B2 (en) | 2010-03-10 | 2013-02-19 | Delphi Technologies, Inc. | Communication system utilizing a hierarchically modulated signal and method thereof |
WO2016029442A1 (en) | 2014-08-29 | 2016-03-03 | 华为技术有限公司 | Data transmission method and device |
CN113726450B (en) * | 2021-07-30 | 2023-05-16 | 中国电子科技集团公司第三十八研究所 | S-band single-address link modeling simulation system |
Family Cites Families (286)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL257397A (en) | 1959-10-08 | |||
US3383598A (en) | 1965-02-15 | 1968-05-14 | Space General Corp | Transmitter for multiplexed phase modulated singaling system |
US3879664A (en) | 1973-05-07 | 1975-04-22 | Signatron | High speed digital communication receiver |
US3878468A (en) | 1974-01-30 | 1975-04-15 | Bell Telephone Labor Inc | Joint equalization and carrier recovery adaptation in data transmission systems |
US4039961A (en) | 1974-09-12 | 1977-08-02 | Nippon Telegraph And Telephone Public Corporation | Demodulator for combined digital amplitude and phase keyed modulation signals |
US3974449A (en) | 1975-03-21 | 1976-08-10 | Bell Telephone Laboratories, Incorporated | Joint decision feedback equalization and carrier recovery adaptation in data transmission systems |
JPS522253A (en) | 1975-06-24 | 1977-01-08 | Kokusai Denshin Denwa Co Ltd <Kdd> | Non-linearity compensation cicuit for high frequency amplifier |
JPS5816802B2 (en) | 1978-04-17 | 1983-04-02 | ケイディディ株式会社 | Nonlinear compensation circuit for high frequency amplifier |
USRE31351E (en) | 1978-08-04 | 1983-08-16 | Bell Telephone Laboratories, Incorporated | Feedback nonlinear equalization of modulated data signals |
US4213095A (en) | 1978-08-04 | 1980-07-15 | Bell Telephone Laboratories, Incorporated | Feedforward nonlinear equalization of modulated data signals |
US4384355A (en) | 1979-10-15 | 1983-05-17 | Bell Telephone Laboratories, Incorporated | Control of coefficient drift for fractionally spaced equalizers |
US4253184A (en) | 1979-11-06 | 1981-02-24 | Bell Telephone Laboratories, Incorporated | Phase-jitter compensation using periodic harmonically related components |
US4422175A (en) | 1981-06-11 | 1983-12-20 | Racal-Vadic, Inc. | Constrained adaptive equalizer |
FR2510331A1 (en) | 1981-07-23 | 1983-01-28 | Leclert Alain | CIRCUIT FOR REGENERATING A CARRIER WAVE |
US4416015A (en) | 1981-12-30 | 1983-11-15 | Bell Telephone Laboratories, Incorporated | Timing acquisition in voiceband data sets |
US4519084A (en) | 1982-09-29 | 1985-05-21 | At&T Bell Laboratories | Matched filter for combating multipath fading |
US4500984A (en) | 1982-09-29 | 1985-02-19 | International Telecommunications Satellite Organization | Equalizer for reducing crosstalk between two FDM/FM carriers in a satellite communications system |
JPS59124950A (en) | 1982-12-29 | 1984-07-19 | Mitsubishi Petrochem Co Ltd | Polyphenylene ether resin composition |
JPS59193658A (en) | 1983-04-18 | 1984-11-02 | Nec Corp | Pseudo error detecting circuit |
FR2546008B1 (en) | 1983-05-11 | 1985-07-12 | Labo Electronique Physique | JOINT ADAPTIVE EQUALIZATION AND DEMODULATION CIRCUIT |
FR2546010B1 (en) | 1983-05-11 | 1985-07-12 | Trt Telecom Radio Electr | CARRIER FREQUENCY EQUALIZATION DEVICE CONTROLLED FROM THE BASE STRIP |
US4637017A (en) | 1984-05-21 | 1987-01-13 | Communications Satellite Corporation | Monitoring of input backoff in time division multiple access communication satellites |
US4709374A (en) | 1984-07-05 | 1987-11-24 | American Telephone And Telegraph Company | Technique for decision-directed equalizer train/retrain |
GB2164823A (en) | 1984-09-17 | 1986-03-26 | Philips Electronic Associated | Television transmitter |
US4896369A (en) | 1984-12-28 | 1990-01-23 | Harris Corporation | Optimal satellite TWT power allocation process for achieving requested availability and maintaining stability in ALPC-type networks |
US4654863A (en) | 1985-05-23 | 1987-03-31 | At&T Bell Laboratories | Wideband adaptive prediction |
US4647873A (en) | 1985-07-19 | 1987-03-03 | General Dynamics, Pomona Division | Adaptive linear FM sweep corrective system |
DE3539818A1 (en) | 1985-11-09 | 1987-05-14 | Bosch Gmbh Robert | METHOD FOR DIGITAL TRANSFER OF DATA AND LANGUAGE |
CA1268828A (en) | 1986-02-08 | 1990-05-08 | Yasuharu Yoshida | Multilevel modulator capable of producing a composite modulated signal comprising a quadrature amplitude modulated component and a phase modulated component |
GB8606572D0 (en) | 1986-03-17 | 1986-04-23 | Hewlett Packard Ltd | Analysis of digital radio transmissions |
DE3642213C2 (en) | 1986-12-10 | 1994-01-27 | Siemens Ag | Satellite communications system |
JPH0773218B2 (en) | 1987-04-21 | 1995-08-02 | 沖電気工業株式会社 | ADPCM encoder / decoder |
DE3886107T2 (en) | 1987-06-23 | 1994-05-26 | Nec Corp | Carrier / noise detector for digital transmission systems. |
US4878030A (en) | 1987-10-23 | 1989-10-31 | Ford Aerospace & Communications Corporation | Linearizer for microwave amplifier |
US4800573A (en) | 1987-11-19 | 1989-01-24 | American Telephone And Telegraph Company | Equalization arrangement |
US4829543A (en) | 1987-12-04 | 1989-05-09 | Motorola, Inc. | Phase-coherent TDMA quadrature receiver for multipath fading channels |
US4847864A (en) | 1988-06-22 | 1989-07-11 | American Telephone And Telegraph Company | Phase jitter compensation arrangement using an adaptive IIR filter |
US4992747A (en) | 1988-08-16 | 1991-02-12 | Myers Glen A | Multiple reuse of an FM band |
US5043734A (en) | 1988-12-22 | 1991-08-27 | Hughes Aircraft Company | Discrete autofocus for ultra-high resolution synthetic aperture radar |
US5016273A (en) | 1989-01-09 | 1991-05-14 | At&E Corporation | Dual communication mode video tape recorder |
US4993047A (en) | 1989-09-05 | 1991-02-12 | At&T Bell Laboratories | Volterra linearizer for digital transmission |
DE4001592A1 (en) | 1989-10-25 | 1991-05-02 | Philips Patentverwaltung | RECEIVER FOR DIGITAL TRANSMISSION SYSTEM |
US5835857A (en) | 1990-03-19 | 1998-11-10 | Celsat America, Inc. | Position determination for reducing unauthorized use of a communication system |
US5206886A (en) | 1990-04-16 | 1993-04-27 | Telebit Corporation | Method and apparatus for correcting for clock and carrier frequency offset, and phase jitter in mulicarrier modems |
US5121414A (en) | 1990-08-09 | 1992-06-09 | Motorola, Inc. | Carrier frequency offset equalization |
US5703874A (en) | 1990-12-05 | 1997-12-30 | Interdigital Technology Corporation | Broadband CDMA overlay system and method |
US5151919A (en) | 1990-12-17 | 1992-09-29 | Ericsson-Ge Mobile Communications Holding Inc. | Cdma subtractive demodulation |
US5581229A (en) | 1990-12-19 | 1996-12-03 | Hunt Technologies, Inc. | Communication system for a power distribution line |
US5111155A (en) | 1991-03-04 | 1992-05-05 | Motorola, Inc. | Distortion compensation means and method |
US5229765A (en) | 1991-05-08 | 1993-07-20 | Halliburton Logging Services, Inc. | SP noise cancellation technique |
US5233632A (en) | 1991-05-10 | 1993-08-03 | Motorola, Inc. | Communication system receiver apparatus and method for fast carrier acquisition |
US5337014A (en) | 1991-06-21 | 1994-08-09 | Harris Corporation | Phase noise measurements utilizing a frequency down conversion/multiplier, direct spectrum measurement technique |
CA2076099A1 (en) | 1991-09-03 | 1993-03-04 | Howard Leroy Lester | Automatic simulcast alignment |
US5285480A (en) | 1991-09-03 | 1994-02-08 | General Electric Company | Adaptive MLSE-VA receiver for digital cellular radio |
JP2776094B2 (en) | 1991-10-31 | 1998-07-16 | 日本電気株式会社 | Variable modulation communication method |
US5221908A (en) | 1991-11-29 | 1993-06-22 | General Electric Co. | Wideband integrated distortion equalizer |
JPH05211670A (en) | 1992-01-14 | 1993-08-20 | Nec Corp | Carrier power/noise power ratio detecting circuit |
US5206889A (en) | 1992-01-17 | 1993-04-27 | Hewlett-Packard Company | Timing interpolator |
US5285474A (en) | 1992-06-12 | 1994-02-08 | The Board Of Trustees Of The Leland Stanford, Junior University | Method for equalizing a multicarrier signal in a multicarrier communication system |
US5237292A (en) | 1992-07-01 | 1993-08-17 | Space Systems/Loral | Quadrature amplitude modulation system with compensation for transmission system characteristics |
JP3135999B2 (en) | 1992-09-18 | 2001-02-19 | リーダー電子株式会社 | CN ratio measuring device |
FR2696295B1 (en) | 1992-09-29 | 1994-12-09 | Europ Agence Spatiale | Device for correcting non-linear distortions of an electronic amplifier. |
BR9405728A (en) | 1993-02-17 | 1995-11-28 | Motorola Inc | Communication system and communication unit |
US5444737A (en) * | 1993-05-05 | 1995-08-22 | National Semiconductor Corporation | Wireless data transceiver |
US5329311A (en) | 1993-05-11 | 1994-07-12 | The University Of British Columbia | System for determining noise content of a video signal in the disclosure |
US5471508A (en) | 1993-08-20 | 1995-11-28 | Hitachi America, Ltd. | Carrier recovery system using acquisition and tracking modes and automatic carrier-to-noise estimation |
JP3560991B2 (en) | 1993-09-20 | 2004-09-02 | 株式会社東芝 | Adaptive maximum likelihood sequence estimator |
US5513215A (en) | 1993-09-20 | 1996-04-30 | Glenayre Electronics, Inc. | High speed simulcast data system using adaptive compensation |
US6088590A (en) | 1993-11-01 | 2000-07-11 | Omnipoint Corporation | Method and system for mobile controlled handoff and link maintenance in spread spectrum communication |
US5412325A (en) | 1993-12-23 | 1995-05-02 | Hughes Aircraft Company | Phase noise measurement system and method |
US5619503A (en) | 1994-01-11 | 1997-04-08 | Ericsson Inc. | Cellular/satellite communications system with improved frequency re-use |
US5577067A (en) | 1994-02-22 | 1996-11-19 | Comsonics, Inc. | Data acquisition and storage system for telecommunication equipment to facilitate alignment and realignment of the telecommunications equipment |
JP3139909B2 (en) | 1994-03-15 | 2001-03-05 | 株式会社東芝 | Hierarchical orthogonal frequency multiplexing transmission system and transmitting / receiving apparatus |
US5642358A (en) | 1994-04-08 | 1997-06-24 | Ericsson Inc. | Multiple beamwidth phased array |
US5430770A (en) | 1994-04-22 | 1995-07-04 | Rockwell International Corp. | Method and apparatus for composite signal separation and PSK/AM/FM demodulation |
EP0683561A1 (en) | 1994-05-18 | 1995-11-22 | Guan-Wu Wang | Low-cost low noise block down-converter with a self-oscillating mixer for satellite broadcast receivers |
JP2561028B2 (en) | 1994-05-26 | 1996-12-04 | 日本電気株式会社 | Sidelobe canceller |
US5903546A (en) | 1994-08-31 | 1999-05-11 | Sony Corporation | Means and method of improving multiplexed transmission and reception by coding and modulating divided digital signals |
FR2724522B1 (en) * | 1994-09-09 | 1997-01-17 | France Telecom | MULTIRESOLUTION CHANNEL CODING AND DECODING METHOD AND DEVICE IN HIGH DEFINITION AND CONVENTIONAL DIGITAL TELEVISION |
US5625640A (en) | 1994-09-16 | 1997-04-29 | Hughes Electronics | Apparatus for and method of broadcast satellite network return-link signal transmission |
US5937004A (en) * | 1994-10-13 | 1999-08-10 | Fasulo, Ii; Albert Joseph | Apparatus and method for verifying performance of digital processing board of an RF receiver |
FR2727590B1 (en) | 1994-11-24 | 1996-12-27 | Alcatel Espace | SATELLITE PAYLOAD WITH INTEGRATED TRANSPARENT CHANNELS |
US5790555A (en) * | 1994-12-05 | 1998-08-04 | Ntt Mobile Communications, Network Inc. | Signal multiplexer and multiplexing method |
US5603084C1 (en) | 1995-03-02 | 2001-06-05 | Ericsson Inc | Method and apparatus for remotely programming a cellular radiotelephone |
US5568520A (en) | 1995-03-09 | 1996-10-22 | Ericsson Inc. | Slope drift and offset compensation in zero-IF receivers |
JP2705623B2 (en) | 1995-03-22 | 1998-01-28 | 日本電気株式会社 | Diversity transmission / reception method and transceiver |
US5898695A (en) | 1995-03-29 | 1999-04-27 | Hitachi, Ltd. | Decoder for compressed and multiplexed video and audio data |
US5644592A (en) | 1995-04-24 | 1997-07-01 | California Institute Of Technology | Parallel interference cancellation for CDMA applications |
US5751766A (en) | 1995-04-27 | 1998-05-12 | Applied Signal Technology, Inc. | Non-invasive digital communications test system |
US5608331A (en) | 1995-06-06 | 1997-03-04 | Hughes Electronics | Noise measurement test system |
US5592481A (en) | 1995-06-06 | 1997-01-07 | Globalstar L.P. | Multiple satellite repeater capacity loading with multiple spread spectrum gateway antennas |
GB9511551D0 (en) | 1995-06-07 | 1995-08-02 | Discovision Ass | Signal processing system |
ZA965340B (en) | 1995-06-30 | 1997-01-27 | Interdigital Tech Corp | Code division multiple access (cdma) communication system |
US5671253A (en) | 1995-07-12 | 1997-09-23 | Thomson Consumer Electronics, Inc. | Apparatus for demodulating and decoding video signals encoded in different formats |
US5606286A (en) | 1995-07-27 | 1997-02-25 | Bains; Devendar S. | Predistortion linearization |
DE19538302C2 (en) | 1995-10-16 | 2001-03-22 | Bosch Gmbh Robert | Methods for terrestrial transmission of digital signals |
JP3788823B2 (en) | 1995-10-27 | 2006-06-21 | 株式会社東芝 | Moving picture encoding apparatus and moving picture decoding apparatus |
GB2307152B (en) | 1995-11-10 | 1999-04-07 | Motorola Ltd | Method and apparatus for enhanced communication capability while maintaining standard channel modulation compatibility |
US5956373A (en) | 1995-11-17 | 1999-09-21 | Usa Digital Radio Partners, L.P. | AM compatible digital audio broadcasting signal transmision using digitally modulated orthogonal noise-like sequences |
US6772182B1 (en) | 1995-12-08 | 2004-08-03 | The United States Of America As Represented By The Secretary Of The Navy | Signal processing method for improving the signal-to-noise ratio of a noise-dominated channel and a matched-phase noise filter for implementing the same |
US5828710A (en) | 1995-12-11 | 1998-10-27 | Delco Electronics Corporation | AFC frequency synchronization network |
DE69736695T8 (en) | 1996-04-12 | 2007-10-25 | Ntt Docomo, Inc. | METHOD AND INSTRUMENT FOR MEASURING THE SIGNAL INTERFERENCE RATIO AND TRANSMITTER |
US6055278A (en) | 1996-04-26 | 2000-04-25 | C-Cor.Net Corporation | Linearization circuits and methods |
US5815531A (en) | 1996-06-12 | 1998-09-29 | Ericsson Inc. | Transmitter for encoded data bits |
US5732113A (en) | 1996-06-20 | 1998-03-24 | Stanford University | Timing and frequency synchronization of OFDM signals |
JP3272246B2 (en) | 1996-07-12 | 2002-04-08 | 株式会社東芝 | Digital broadcast receiver |
JPH1054855A (en) | 1996-08-09 | 1998-02-24 | Advantest Corp | Spectrum analyzer |
FI963317A (en) | 1996-08-26 | 1998-02-27 | Nokia Technology Gmbh | Carrier wave synchronization of two-dimensional multi-plane modulation alphabet |
US6411797B1 (en) | 1996-09-20 | 2002-06-25 | Itt Manufacturing Enterprises, Inc. | Method and apparatus for performance characterization of satellite transponders |
US5946625A (en) | 1996-10-10 | 1999-08-31 | Ericsson, Inc. | Method for improving co-channel interference in a cellular system |
US6178158B1 (en) | 1996-10-14 | 2001-01-23 | Nippon Telegraph & Telephone Corporation | Method and apparatus for transmission and reception |
DE19646164A1 (en) | 1996-11-08 | 1998-05-14 | Deutsche Telekom Ag | Process for the transmission of digital signals |
DE19647833B4 (en) | 1996-11-19 | 2005-07-07 | Deutsches Zentrum für Luft- und Raumfahrt e.V. | Method for simultaneous radio transmission of digital data between a plurality of subscriber stations and a base station |
US6097768A (en) | 1996-11-21 | 2000-08-01 | Dps Group, Inc. | Phase detector for carrier recovery in a DQPSK receiver |
US5960040A (en) | 1996-12-05 | 1999-09-28 | Raytheon Company | Communication signal processors and methods |
JP3346198B2 (en) | 1996-12-10 | 2002-11-18 | 富士ゼロックス株式会社 | Active silencer |
US5987069A (en) | 1996-12-24 | 1999-11-16 | Gte Government Systems Corporation | Method and apparatus for variably allocating upstream and downstream communication spectra |
JPH10190497A (en) | 1996-12-27 | 1998-07-21 | Fujitsu Ltd | Sir measuring device |
US5978652A (en) | 1997-01-10 | 1999-11-02 | Space Systems/Loral, Inc. | Common direct broadcasting service system |
US5970156A (en) | 1997-02-14 | 1999-10-19 | Telefonaktiebolaget Lm Ericsson | Method and apparatus for reducing periodic interference in audio signals |
US6078645A (en) | 1997-02-20 | 2000-06-20 | Lucent Technologies Inc. | Apparatus and method for monitoring full duplex data communications |
JP3586348B2 (en) | 1997-03-05 | 2004-11-10 | 富士通株式会社 | Signal to interference power ratio measurement apparatus, signal to interference power ratio measurement method, and transmission power control method under CDMA communication system |
US5870443A (en) | 1997-03-19 | 1999-02-09 | Hughes Electronics Corporation | Symbol timing recovery and tracking method for burst-mode digital communications |
US6212360B1 (en) | 1997-04-09 | 2001-04-03 | Ge Capital Spacenet Services, Inc. | Methods and apparatus for controlling earth-station transmitted power in a VSAT network |
EP0874474A3 (en) | 1997-04-21 | 2000-08-23 | Motorola, Inc. | Communication system and method for recovery signals utilizing separation techniques |
US6040800A (en) | 1997-04-22 | 2000-03-21 | Ericsson Inc. | Systems and methods for locating remote terminals in radiocommunication systems |
US5905943A (en) * | 1997-04-29 | 1999-05-18 | Globalstar L.P. | System for generating and using global radio frequency maps |
US6314441B1 (en) | 1997-04-30 | 2001-11-06 | Agere Systems Inc | Robust method for providing tap leakage in adaptive equalizer systems |
AU7563398A (en) | 1997-05-02 | 1998-11-27 | Uscx | High latitude geostationary satellite system |
US5970098A (en) | 1997-05-02 | 1999-10-19 | Globespan Technologies, Inc. | Multilevel encoder |
US6172970B1 (en) * | 1997-05-05 | 2001-01-09 | The Hong Kong University Of Science And Technology | Low-complexity antenna diversity receiver |
JPH10327204A (en) | 1997-05-26 | 1998-12-08 | Nec Corp | Phase locked loop circuit using equalizer |
JPH10336262A (en) | 1997-05-28 | 1998-12-18 | Ikegami Tsushinki Co Ltd | Transmission quality measurement circuit for digital signal |
US6019318A (en) | 1997-06-16 | 2000-02-01 | Hugehs Electronics Corporation | Coordinatable system of inclined geosynchronous satellite orbits |
US6134282A (en) | 1997-06-18 | 2000-10-17 | Lsi Logic Corporation | Method for lowpass filter calibration in a satellite receiver |
US5999793A (en) | 1997-06-18 | 1999-12-07 | Lsi Logic Corporation | Satellite receiver tuner chip with frequency synthesizer having an externally configurable charge pump |
US5870439A (en) | 1997-06-18 | 1999-02-09 | Lsi Logic Corporation | Satellite receiver tuner chip having reduced digital noise interference |
US5819157A (en) | 1997-06-18 | 1998-10-06 | Lsi Logic Corporation | Reduced power tuner chip with integrated voltage regulator for a satellite receiver system |
US6539050B1 (en) | 1997-06-26 | 2003-03-25 | Hughes Electronics Corporation | Method for transmitting wideband signals via a communication system adapted for narrow-band signal transmission |
US5966412A (en) | 1997-06-30 | 1999-10-12 | Thomson Consumer Electronics, Inc. | Apparatus and method for processing a Quadrature Amplitude Modulated (QAM) signal |
US6072841A (en) | 1997-07-01 | 2000-06-06 | Hughes Electronics Corporation | Block phase estimator for the coherent detection of non-differentially phase modulated data bursts on rician fading channels |
US6049566A (en) | 1997-07-24 | 2000-04-11 | Trw Inc. | High efficiency signaling with minimum spacecraft hardware |
US5970429A (en) | 1997-08-08 | 1999-10-19 | Lucent Technologies, Inc. | Method and apparatus for measuring electrical noise in devices |
US6108374A (en) | 1997-08-25 | 2000-08-22 | Lucent Technologies, Inc. | System and method for measuring channel quality information |
US6052586A (en) | 1997-08-29 | 2000-04-18 | Ericsson Inc. | Fixed and mobile satellite radiotelephone systems and methods with capacity sharing |
US6125148A (en) | 1997-08-29 | 2000-09-26 | Telefonaktiebolaget Lm Ericsson | Method for demodulating information in a communication system that supports multiple modulation schemes |
US5940025A (en) | 1997-09-15 | 1999-08-17 | Raytheon Company | Noise cancellation method and apparatus |
US6434384B1 (en) | 1997-10-17 | 2002-08-13 | The Boeing Company | Non-uniform multi-beam satellite communications system and method |
US6272679B1 (en) | 1997-10-17 | 2001-08-07 | Hughes Electronics Corporation | Dynamic interference optimization method for satellites transmitting multiple beams with common frequencies |
US6002713A (en) | 1997-10-22 | 1999-12-14 | Pc Tel, Inc. | PCM modem equalizer with adaptive compensation for robbed bit signalling |
US6477398B1 (en) | 1997-11-13 | 2002-11-05 | Randell L. Mills | Resonant magnetic susceptibility imaging (ReMSI) |
US5966048A (en) | 1997-11-25 | 1999-10-12 | Hughes Electronics Corporation | Low IMD amplification method and apparatus |
JP3392028B2 (en) | 1997-11-28 | 2003-03-31 | 株式会社ケンウッド | Hierarchical transmission digital demodulator |
ATE190785T1 (en) | 1997-12-18 | 2000-04-15 | Europ Des Satellites Soc | METHOD AND DEVICE FOR DETERMINING AN WORKING POINT OF A NON-LINEAR AMPLIFIER IN A TRANSMISSION CHANNEL |
US6650178B1 (en) | 1997-12-18 | 2003-11-18 | Sony International (Europe) Gmbh | N-port direct receiver |
US6128357A (en) | 1997-12-24 | 2000-10-03 | Mitsubishi Electric Information Technology Center America, Inc (Ita) | Data receiver having variable rate symbol timing recovery with non-synchronized sampling |
US5952834A (en) | 1998-01-14 | 1999-09-14 | Advanced Testing Technologies, Inc. | Low noise signal synthesizer and phase noise measurement system |
US5909454A (en) | 1998-01-20 | 1999-06-01 | General Instrument Corporation | Intermediate rate applications of punctured convolutional codes for 8PSK trellis modulation over satellite channels |
US5995536A (en) * | 1998-01-23 | 1999-11-30 | Bsd Broadband, N.V. | System for discrete data transmission with noise-like, broadband signals |
US6084919A (en) | 1998-01-30 | 2000-07-04 | Motorola, Inc. | Communication unit having spectral adaptability |
US6131013A (en) | 1998-01-30 | 2000-10-10 | Motorola, Inc. | Method and apparatus for performing targeted interference suppression |
US6185716B1 (en) | 1998-01-30 | 2001-02-06 | Maxtor Corporation | Dual detector read channel with semi-soft detection |
US6219095B1 (en) | 1998-02-10 | 2001-04-17 | Wavetek Corporation | Noise measurement system |
IL123739A (en) | 1998-03-19 | 2001-11-25 | Infineon Technologies Ag | Method and apparatus for clock timing recovery in xdsl, particularly vdsl modems |
US6141534A (en) | 1998-03-25 | 2000-10-31 | Spacecode Llc | Communication satellite system with dynamic downlink resource allocation |
US6313885B1 (en) | 1998-03-25 | 2001-11-06 | Samsung Electronics Co., Ltd. | DTV receiver with baseband equalization filters for QAM signal and for VSB signal which employ common elements |
US6192088B1 (en) | 1998-03-31 | 2001-02-20 | Lucent Technologies Inc. | Carrier recovery system |
US6433835B1 (en) | 1998-04-17 | 2002-08-13 | Encamera Sciences Corporation | Expanded information capacity for existing communication transmission systems |
US6657978B1 (en) | 1998-04-23 | 2003-12-02 | Transworld Communications (Usa), Inc. | Optimized integrated high capacity digital satellite trunking network |
US6731622B1 (en) | 1998-05-01 | 2004-05-04 | Telefonaktiebolaget Lm Ericsson (Publ) | Multipath propagation delay determining means using periodically inserted pilot symbols |
US6535497B1 (en) | 1998-05-11 | 2003-03-18 | Telefonaktiebolaget Lm Ericsson (Publ) | Methods and systems for multiplexing of multiple users for enhanced capacity radiocommunications |
JP2966396B1 (en) | 1998-05-22 | 1999-10-25 | 株式会社ケンウッド | BS digital broadcast receiver |
US6597750B1 (en) | 1998-06-19 | 2003-07-22 | Thomson Licensing S.A. | Opposite polarization interference cancellation in satellite communication |
US6426822B1 (en) | 1998-06-25 | 2002-07-30 | Ipicom, Inc. | Method and apparatus for reducing non-linear characteristics of a signal modulator by coherent data collection |
JP2000031944A (en) | 1998-07-07 | 2000-01-28 | Matsushita Electric Ind Co Ltd | Transmitter, receiver and data transmission method |
US6304594B1 (en) | 1998-07-27 | 2001-10-16 | General Dynamics Government Systems Corporation | Interference detection and avoidance technique |
US6452977B1 (en) | 1998-09-15 | 2002-09-17 | Ibiquity Digital Corporation | Method and apparatus for AM compatible digital broadcasting |
EP1033004A1 (en) | 1998-09-18 | 2000-09-06 | Hughes Electronics Corporation | Method and constructions for space-time codes for psk constellations for spatial diversity in multiple-element antenna systems |
GB9821839D0 (en) * | 1998-10-08 | 1998-12-02 | Koninkl Philips Electronics Nv | Radio receiver |
US6246717B1 (en) | 1998-11-03 | 2001-06-12 | Tektronix, Inc. | Measurement test set and method for in-service measurements of phase noise |
DE69920737T2 (en) | 1998-11-03 | 2005-10-13 | Broadcom Corp., Irvine | QAM / VSB TWO-DAY RECEIVER |
US6404819B1 (en) | 1998-11-20 | 2002-06-11 | Lucent Technologies Inc. | System and method for generating NRZ signals from RZ signals in communications networks |
US6104747A (en) | 1998-11-30 | 2000-08-15 | Motorola, Inc. | Method for determining optimum number of complex samples for coherent averaging in a communication system |
US6320919B1 (en) | 1998-11-30 | 2001-11-20 | Ericsson Inc. | Adaptive channel characterization using decoded symbols |
US6335951B1 (en) * | 1998-12-04 | 2002-01-01 | Itt Manufacturing Enterprises, Inc. | Programmable waveform generator for a global positioning system |
US6587517B1 (en) * | 1998-12-23 | 2003-07-01 | Nortel Networks Limited | Multi-stage receiver |
US6515713B1 (en) | 1998-12-31 | 2003-02-04 | Lg Electronics Inc. | Method and apparatus which compensates for channel distortion |
US6678520B1 (en) | 1999-01-07 | 2004-01-13 | Hughes Electronics Corporation | Method and apparatus for providing wideband services using medium and low earth orbit satellites |
US6166601A (en) | 1999-01-07 | 2000-12-26 | Wiseband Communications Ltd. | Super-linear multi-carrier power amplifier |
TW559668B (en) | 1999-02-08 | 2003-11-01 | Advantest Corp | Apparatus for and method of measuring a jitter |
US6529715B1 (en) * | 1999-02-26 | 2003-03-04 | Lucent Technologies Inc. | Amplifier architecture for multi-carrier wide-band communications |
JP2000278341A (en) | 1999-03-25 | 2000-10-06 | Sanyo Electric Co Ltd | Quadrature phase demodulation circuit |
EP1041712B1 (en) * | 1999-03-31 | 2009-01-28 | NTT Mobile Communications Network Inc. | Feedforward amplifier |
US6369648B1 (en) | 1999-04-21 | 2002-04-09 | Hughes Electronics Corporation | Linear traveling wave tube amplifier utilizing input drive limiter for optimization |
US6177836B1 (en) | 1999-05-07 | 2001-01-23 | The Aerospace Corporation | Feed forward linearized traveling wave tube |
ES2251835T3 (en) | 1999-06-18 | 2006-05-01 | Ses Astra S.A. | PROCEDURE AND APPLIANCE TO DETERMINE THE CHARACTERISTICS OF COMPONENTS OF A TRANSMISSION ROAD. |
WO2000079753A1 (en) | 1999-06-23 | 2000-12-28 | At & T Wireless Services, Inc. | Methods and apparatus for use in obtaining frequency synchronization in an ofdm communication system |
US6556639B1 (en) | 1999-06-24 | 2003-04-29 | Ibiquity Digital Corporation | Method and apparatus for determining transmission mode and synchronization for a digital audio broadcasting signal |
GB9915417D0 (en) | 1999-07-02 | 1999-09-01 | Nds Ltd | Improvements in or relating to hierarchical coding |
US6891897B1 (en) | 1999-07-23 | 2005-05-10 | Nortel Networks Limited | Space-time coding and channel estimation scheme, arrangement and method |
US6775521B1 (en) | 1999-08-09 | 2004-08-10 | Broadcom Corporation | Bad frame indicator for radio telephone receivers |
US6574235B1 (en) | 1999-08-12 | 2003-06-03 | Ericsson Inc. | Methods of receiving co-channel signals by channel separation and successive cancellation and related receivers |
KR100314113B1 (en) | 1999-08-25 | 2001-11-15 | 구자홍 | matched filter and filtering method, apparatus and method for receiving plural digital broadcast using digital filter |
JP2001069112A (en) | 1999-08-25 | 2001-03-16 | Sony Corp | Ofdm transmitter, ofdm receiver, ofdm communication equipment using them and ofdm communication method |
US6430233B1 (en) * | 1999-08-30 | 2002-08-06 | Hughes Electronics Corporation | Single-LNB satellite data receiver |
KR20010019997A (en) | 1999-08-31 | 2001-03-15 | 박종섭 | Channel Simulator for wide bend CDMA Signal In IMT-2000 System |
US6249180B1 (en) | 1999-09-08 | 2001-06-19 | Atmel Corporation | Phase noise and additive noise estimation in a QAM demodulator |
AU7358100A (en) * | 1999-09-09 | 2001-04-10 | Home Wireless Networks, Inc. | Turbo detection of space-time codes |
US6560295B1 (en) | 1999-09-15 | 2003-05-06 | Hughes Electronics Corporation | Method of generating space-time codes for generalized layered space-time architectures |
US7161931B1 (en) | 1999-09-20 | 2007-01-09 | Broadcom Corporation | Voice and data exchange over a packet based network |
US6535545B1 (en) | 1999-10-15 | 2003-03-18 | Rf Waves Ltd. | RF modem utilizing saw resonator and correlator and communications transceiver constructed therefrom |
US6577353B1 (en) * | 1999-10-21 | 2003-06-10 | General Electric Company | Optimization of television reception by selecting among or combining multiple antenna inputs |
US7079585B1 (en) | 1999-11-23 | 2006-07-18 | Thomson Licensing | Gray encoding for hierarchical QAM transmission systems |
CN1274123C (en) * | 1999-11-23 | 2006-09-06 | 汤姆森特许公司 | Error detection/correction coding for hierarchical QAM transmission systems |
US7073116B1 (en) | 1999-11-23 | 2006-07-04 | Thomson Licensing | Error detection/correction coding for hierarchical QAM transmission systems |
US6535801B1 (en) | 2000-01-28 | 2003-03-18 | General Dynamics Decision Systems, Inc. | Method and apparatus for accurately determining the position of satellites in geosynchronous orbits |
JP2001223665A (en) | 2000-02-08 | 2001-08-17 | Matsushita Electric Ind Co Ltd | Signal coding transmitter, signal decoding receiver, and program recording medium |
JP3685677B2 (en) | 2000-03-01 | 2005-08-24 | 三洋電機株式会社 | Digital broadcast receiver |
JP2001267982A (en) | 2000-03-22 | 2001-09-28 | Matsushita Electric Ind Co Ltd | Sttd encoding method and diversity transmitter |
US20020154705A1 (en) | 2000-03-22 | 2002-10-24 | Walton Jay R. | High efficiency high performance communications system employing multi-carrier modulation |
CA2302004A1 (en) | 2000-03-22 | 2001-09-22 | Vajira N. S. Samarasooriya | Method and system for achieving carrier frequency synchronization in a high speed receiver |
US6429740B1 (en) | 2000-03-23 | 2002-08-06 | The Aerospace Corporation | High power amplifier linearization method using extended saleh model predistortion |
US6307435B1 (en) | 2000-03-23 | 2001-10-23 | The Aerospace Corporation | High power amplifier linearization method using modified linear-log model predistortion |
US6741662B1 (en) | 2000-04-17 | 2004-05-25 | Intel Corporation | Transmitter linearization using fast predistortion |
US7885314B1 (en) | 2000-05-02 | 2011-02-08 | Kenneth Scott Walley | Cancellation system and method for a wireless positioning system |
US6377116B1 (en) | 2000-05-08 | 2002-04-23 | Iowa State University Research Foundation, Inc. | Pre-distorter and corresponding method for deriving same |
JP3786343B2 (en) | 2000-05-12 | 2006-06-14 | 日本ビクター株式会社 | Optical disk playback device |
US6956841B1 (en) | 2000-05-24 | 2005-10-18 | Nokia Networks Oy | Receiver and method of receiving a desired signal |
SE517030C2 (en) | 2000-06-06 | 2002-04-02 | Ericsson Telefon Ab L M | Method and apparatus for selecting modulation and coding rules in a radio communication system |
US6297691B1 (en) | 2000-06-09 | 2001-10-02 | Rosemount Inc. | Method and apparatus for demodulating coherent and non-coherent modulated signals |
JP2002009728A (en) | 2000-06-23 | 2002-01-11 | Hitachi Kokusai Electric Inc | Orthogonal frequency division multiplexing modulation transmission apparatus |
US7154958B2 (en) | 2000-07-05 | 2006-12-26 | Texas Instruments Incorporated | Code division multiple access wireless system with time reversed space time block transmitter diversity |
CA2381811C (en) | 2000-08-02 | 2007-01-30 | Mobile Satellite Ventures Lp | Coordinated satellite-terrestrial frequency reuse |
US7054384B1 (en) * | 2000-08-04 | 2006-05-30 | Lucent Technologies Inc. | Power amplifier sharing in a wireless communication system with transmit diversity |
US6522683B1 (en) | 2000-08-10 | 2003-02-18 | Qualcomm, Incorporated | Method and apparatus for adaptive linear equalization for walsh covered modulation |
DE10043743A1 (en) | 2000-09-05 | 2002-03-14 | Infineon Technologies Ag | Automatic frequency correction for mobile radio receivers |
US6718184B1 (en) | 2000-09-28 | 2004-04-06 | Lucent Technologies Inc. | Method and system for adaptive signal processing for an antenna array |
JP3602047B2 (en) | 2000-10-05 | 2004-12-15 | シャープ株式会社 | Hierarchical transmission digital signal demodulator |
US6745050B1 (en) | 2000-10-23 | 2004-06-01 | Massachusetts Institute Of Technology | Multichannel multiuser detection |
US7190683B2 (en) | 2000-10-27 | 2007-03-13 | L-3 Communications Corporation | Two-dimensional channel bonding in a hybrid CDMA/FDMA fixed wireless access system to provide finely variable rate channels |
US7042956B2 (en) | 2000-11-06 | 2006-05-09 | Hesham El-Gamal | Method and system for utilizing space-time codes for block fading channels |
JP2002164866A (en) | 2000-11-29 | 2002-06-07 | Nec Corp | Broadcasting device using ofdm modulation method |
JP3387918B2 (en) | 2000-12-04 | 2003-03-17 | 富士通株式会社 | Time equalization method and device |
US7203158B2 (en) | 2000-12-06 | 2007-04-10 | Matsushita Electric Industrial Co., Ltd. | OFDM signal transmission system, portable terminal, and e-commerce system |
US6567762B2 (en) * | 2000-12-22 | 2003-05-20 | Agilent Technologies, Inc. | Dynamic range extension apparatus and method |
US6731700B1 (en) | 2001-01-04 | 2004-05-04 | Comsys Communication & Signal Processing Ltd. | Soft decision output generator |
JP3545726B2 (en) | 2001-02-27 | 2004-07-21 | 松下電器産業株式会社 | Receiver device |
US20030002471A1 (en) | 2001-03-06 | 2003-01-02 | Crawford James A. | Method for estimating carrier-to-noise-plus-interference ratio (CNIR) for OFDM waveforms and the use thereof for diversity antenna branch selection |
US6922439B2 (en) | 2001-03-16 | 2005-07-26 | Advantest Corporation | Apparatus for and method of measuring jitter |
US7471735B2 (en) | 2001-04-27 | 2008-12-30 | The Directv Group, Inc. | Maximizing power and spectral efficiencies for layered and conventional modulations |
US7778365B2 (en) | 2001-04-27 | 2010-08-17 | The Directv Group, Inc. | Satellite TWTA on-line non-linearity measurement |
US7209524B2 (en) | 2001-04-27 | 2007-04-24 | The Directv Group, Inc. | Layered modulation for digital signals |
US7639759B2 (en) | 2001-04-27 | 2009-12-29 | The Directv Group, Inc. | Carrier to noise ratio estimations from a received signal |
US7173981B1 (en) | 2001-04-27 | 2007-02-06 | The Directv Group, Inc. | Dual layer signal processing in a layered modulation digital signal system |
US7184473B2 (en) | 2001-04-27 | 2007-02-27 | The Directv Group, Inc. | Equalizers for layered modulated and other signals |
GB2375016B (en) | 2001-04-27 | 2005-03-16 | Tandberg Television Asa | Satellite up-link fade compensation |
US7453933B2 (en) | 2001-05-04 | 2008-11-18 | Lucent Technologies Inc. | Method of estimating a signal-to-interference+noise ratio (SINR) using data samples |
US7046739B2 (en) * | 2001-05-18 | 2006-05-16 | Southwest Research Institute | Pre-distortion of input signals to form constant envelope signal outputs |
US7106792B2 (en) | 2001-06-04 | 2006-09-12 | Qualcomm, Inc. | Method and apparatus for estimating the signal to interference-plus-noise ratio of a wireless channel |
US6956924B2 (en) | 2001-08-14 | 2005-10-18 | Northrop Grumman Corporation | Efficient implementation of a decision directed phase locked loop (DD-PLL) for use with short block code in digital communication systems |
US7239876B2 (en) | 2001-09-06 | 2007-07-03 | Motorola, Inc. | Method for increased location receiver sensitivity |
US7039122B2 (en) * | 2001-10-17 | 2006-05-02 | Itt Manufacturing Enterprises, Inc. | Method and apparatus for generating a composite signal |
US6700442B2 (en) * | 2001-11-20 | 2004-03-02 | Thomas Quang Ha | N way phase cancellation power amplifier |
US7263119B1 (en) | 2001-11-29 | 2007-08-28 | Marvell International Ltd. | Decoding method and apparatus |
US7092438B2 (en) | 2002-01-22 | 2006-08-15 | Siemens Communications, Inc. | Multilevel decision feedback equalizer |
EP1335512B1 (en) | 2002-02-05 | 2007-02-28 | Hughes Electronics Corporation | Preprocessing of the superimposed signals in a layered modulation digital transmission scheme to use legacy receivers |
US7065153B2 (en) * | 2002-02-06 | 2006-06-20 | The Boeing Company | High speed monolithic microwave integrated circuit (MMIC) quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM) modulators |
KR20030076259A (en) | 2002-03-19 | 2003-09-26 | 술저 헥시스 악티엔게젤샤프트 | A fuel cell battery with an integrated heat exchanger |
US7197084B2 (en) | 2002-03-27 | 2007-03-27 | Qualcomm Incorporated | Precoding for a multipath channel in a MIMO system |
US7020226B1 (en) * | 2002-04-04 | 2006-03-28 | Nortel Networks Limited | I/Q distortion compensation for the reception of OFDM signals |
US6809587B2 (en) | 2002-04-23 | 2004-10-26 | Mitec Telecom Inc. | Active predistorting linearizer with agile bypass circuit for safe mode operation |
US7274876B2 (en) | 2002-06-06 | 2007-09-25 | At&T Corp. | Integrated electrical/optical hybrid communication system with revertive hitless switch |
US20070121718A1 (en) | 2002-06-06 | 2007-05-31 | Chin-Liang Wang | System and Method for Time-Domain Equalization in Discrete Multi-tone Systems |
TWI324463B (en) | 2002-07-01 | 2010-05-01 | Hughes Electronics Corp | Improving hierarchical 8psk performance |
US6885708B2 (en) | 2002-07-18 | 2005-04-26 | Motorola, Inc. | Training prefix modulation method and receiver |
US8229003B2 (en) | 2002-09-06 | 2012-07-24 | Koninklijke Philips Electronics N.V. | Parameter encoding for an improved ATSC DTV system |
US8170513B2 (en) | 2002-10-25 | 2012-05-01 | Qualcomm Incorporated | Data detection and demodulation for wireless communication systems |
US7529312B2 (en) | 2002-10-25 | 2009-05-05 | The Directv Group, Inc. | Layered modulation for terrestrial ATSC applications |
CA2502924C (en) | 2002-10-25 | 2009-12-15 | The Directv Group, Inc. | Maximizing power and spectral efficiencies for layered and conventional modulations |
EP1563601B1 (en) | 2002-10-25 | 2010-03-17 | The Directv Group, Inc. | Estimating the operating point on a nonlinear traveling wave tube amplifier |
US7548598B2 (en) | 2003-04-07 | 2009-06-16 | Harris Corporation | Method and apparatus for iteratively improving the performance of coded and interleaved communication systems |
US6999510B2 (en) | 2003-04-18 | 2006-02-14 | Optichron, Inc. | Nonlinear inversion |
CN1792057A (en) | 2003-05-16 | 2006-06-21 | 汤姆森许可贸易公司 | A unified receiver for layered and hierarchical modulation systems |
US6987068B2 (en) * | 2003-06-14 | 2006-01-17 | Intel Corporation | Methods to planarize semiconductor device and passivation layer |
US7230992B2 (en) | 2003-11-26 | 2007-06-12 | Delphi Technologies, Inc. | Method to create hierarchical modulation in OFDM |
US20070297533A1 (en) | 2006-06-26 | 2007-12-27 | Interdigital Technology Corporation | Apparatus and methods for implementing hierarchical modulation and demodulation for geran evolution |
-
2003
- 2003-07-03 AU AU2003281452A patent/AU2003281452A1/en not_active Abandoned
- 2003-07-03 TW TW092118215A patent/TWI279113B/en not_active IP Right Cessation
- 2003-07-03 WO PCT/US2003/020847 patent/WO2004006455A1/en not_active Application Discontinuation
- 2003-07-03 US US10/519,375 patent/US7738587B2/en not_active Expired - Fee Related
- 2003-07-03 ES ES03742393.6T patent/ES2604453T3/en not_active Expired - Lifetime
- 2003-07-03 CA CA2491259A patent/CA2491259C/en not_active Expired - Fee Related
- 2003-07-03 EP EP03742393.6A patent/EP1529347B1/en not_active Expired - Lifetime
- 2003-07-03 AR ARP030102421A patent/AR040395A1/en not_active Application Discontinuation
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2004
- 2004-03-02 NO NO20040918A patent/NO335767B1/en not_active IP Right Cessation
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EP1529347A1 (en) | 2005-05-11 |
US7738587B2 (en) | 2010-06-15 |
TWI279113B (en) | 2007-04-11 |
NO335767B1 (en) | 2015-02-09 |
US20060050805A1 (en) | 2006-03-09 |
NO20040918L (en) | 2004-03-02 |
EP1529347A4 (en) | 2007-10-31 |
ES2604453T3 (en) | 2017-03-07 |
WO2004006455A1 (en) | 2004-01-15 |
AR040395A1 (en) | 2005-03-30 |
AU2003281452A1 (en) | 2004-01-23 |
EP1529347B1 (en) | 2016-08-24 |
CA2491259C (en) | 2013-09-17 |
TW200405706A (en) | 2004-04-01 |
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