1. Field of the Invention
The present invention relates to systems and methods for transmitting digital signals in ATSC applications, particularly signals using layered modulations.
2. Description of the Related Art
Digital signal communication systems have been used in various fields, including digital TV signal transmission, either terrestrial or satellite. 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.
The conventional method of increasing spectral capacity is to move to a higher-order modulation, such as from quadrature phase shift keying (QPSK) to eight phase shift keying (8PSK) or sixteen quadrature amplitude modulation (16QAM). Unfortunately, QPSK receivers cannot demodulate 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.
It is advantageous for systems and methods of transmitting signals to accommodate enhanced and increased data throughput without requiring additional frequency. In addition, it is advantageous for enhanced and increased throughput signals for new receivers to be backwards compatible with legacy receivers. There is further an advantage for systems and methods which allow transmission signals to be upgraded from a source separate from the legacy transmitter.
It has been proposed that a layered modulation signal, transmitting non-coherently (asynchronously) both upper and lower layer signals, can be employed to meet these needs. Such layered modulation systems allow higher information throughput with backwards compatibility. Even when backward compatibility is not required (such as with an entirely new system), layered modulation can still be advantageous because it requires a TWTA peak power significantly lower than that for a conventional 8PSK or 16QAM modulation format for a given throughput.
The Advanced Television Systems Committee, Inc., is an international, non-profit organization developing voluntary standards for digital television. The ATSC member organizations represent the broadcast, broadcast equipment, motion picture, consumer electronics, computer, cable, satellite, and semiconductor industries. The ATSC works to coordinate television standards among different communications media focusing on digital television, interactive systems, and broadband multimedia communications. ATSC also develops digital television implementation strategies and present educational seminars on the ATSC standards. ATSC Digital TV Standards include digital high definition television (HDTV), standard definition television (SDTV), data broadcasting, multichannel surround-sound audio, and satellite direct-to-home broadcasting.
For example, the terrestrial ATSC describes the characteristics of an RF/transmission subsystem, which is referred to as the VSB subsystem, of the Digital Television Standard. The VSB subsystem offers two modes: a terrestrial broadcast mode (8 VSB), and a high data rate mode (16 VSB). See “ATSC Standard: Digital Television Standard, Revision B with Amendments 1 and 2”, The Advanced Television Systems Committee, May 19, 2003, which is incorporated by reference herein. In the ATSC standard for digital television and many other communications standards, the allocated frequency bandwidth cannot be increased. Given the stipulated ATSC modulation and coding techniques, the information throughput for ATSC is fixed over the channel bandwidth of 6 MHz.
Accordingly, there is a need for systems and methods that expand capacity of the allocated ATSC frequency bandwidth. As discussed hereafter, the present invention meets these needs.
Layered modulation transmits two or more signals simultaneously. The signals are layered in terms of power level and are generated non-coherently with respect to each other. Upon reception, these signals are processed into separate data transports for a combined throughput greater than that afforded by the conventional modulation method which allows only one layer of signal. Embodiments of the present invention utilize layered modulation to provide additional throughput over the ATSC signal band.
Like other layered modulation applications, embodiments of the invention allow a new service to be added to existing service while maintaining backward compatibility. Specifically, performance of the legacy ATSC service with existing receivers will be little affected, and little extra power will be required to transmit the legacy signal. The signal for the new service will be transmitted typically from a separate antenna. The maximum range of the new service will be shorter than that of the legacy service, as will become clear later in this document.
A typical transmission system of the invention includes a first antenna for transmitting an upper layer signal comprising an 8-VSB signal and a second antenna for transmitting a lower layer signal. A layered modulation signal comprises the upper layer signal and the lower layer signal both interfering in a common frequency band. At least one receiver demodulates the upper layer signal directly from the layered modulation signal and demodulates the lower layer signal after subtracting the upper layer signal from the layered modulation signal. The second antenna can have a selectively limited range so that the lower layer signal does not interfere with the upper layer signal in a range where the lower layer signal could not be demodulated.
The selectively limited range can be produced by reducing a second antenna height relative to a first antenna height. Alternately or in combination with the reduced second antenna height, the second antenna can be a shaped-beam antenna in order to produce the selectively limited range.
In a typical embodiment, the upper layer signal comprises a legacy signal and the lower layer signal comprises a 2-VSB signal. However, the lower layer signal can alternately be a QPSK or other signal.
A typical receiver of the invention includes a first demodulator for demodulating an upper layer signal comprising an 8-VSB signal directly from a layered modulation signal and a second demodulator for demodulating a lower layer signal after subtracting the upper layer signal from the layered modulation signal. The layered modulation signal comprises both the upper layer signal and a lower layer signal both interfering in a common frequency band.
The upper layer signal can be subtracted from the layered modulation signal with a carrier of the upper layer signal included in the subtraction. Alternately, the upper layer signal can be subtracted from the layered modulation signal with the carrier of the upper layer signal removed before the subtraction.
Referring now to the drawings in which like reference numbers represent corresponding parts throughout:
In the following description of the preferred embodiment, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration a specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.
1. ATSC Terrestrial Transmission Characteristics
The incoming data is randomized and then processed for forward error correction (FEC) in the form of Reed-Solomon (RS) coding (20 RS parity bytes are added to each packet), ⅙ data field interleaving and ⅔ rate trellis coding. The randomization and FEC processes are not applied to the sync byte of the transport packet, which is represented in transmission by a data segment sync signal as described below. Following randomization and forward error correction processing, the data packets are formatted into Data Frames for transmission and Data Segment Sync and Data Field Sync are added.
which is twice of 5.38 MHz for a single-sideband (SSB) signal The frequency of a data segment (in data segments/s) is given by
The data frame rate (in frames/s) is given by
The symbol rate and the transport rate are locked to each other in frequency.
Referring back to
The data randomizer 102 is coupled to a Reed-Soloman encoder 104. The RS code used in the VSB transmission subsystem shall be a t=10 (207,187) code. The RS data block size is 187 bytes, with 20 RS parity bytes added for error correction. A total RS block size of 207 bytes is transmitted per data segment. In creating bytes from the serial bit stream, the MSB shall be the first serial bit. The 20 RS parity bytes shall be sent at the end of the data segment.
The interleaver 106 employed in the VSB transmitter 100 can be a 52 data segment (intersegment) convolutional byte interleaver 106. Interleaving is provided to a depth of about 1/6 of a data field (4 ms deep). Only data bytes are interleaved. The interleaver shall be synchronized to the first data byte of the data field. Intrasegment interleaving is also performed for the benefit of the trellis coding process performed later.
Following the interleaver 106, data is passed to the trellis encoder 108 which includes a precoder and symbol mapper. The 8 VSB trellis encoder 108 employs a ⅔ rate (R=⅔) trellis code (with one unencoded bit which is precoded). That is, one input bit is encoded into two output bits using a ½ rate convolutional code while the other input bit is precoded. The signaling waveform used with the trellis code is an 8-level (3 bit) one-dimensional constellation. Thus, the transmitted signal is referred to as 8 VSB. A four-state trellis encoder is used and trellis code intrasegment interleaving is used. This employs twelve identical trellis encoders 108 and precoders operating on interleaved data symbols. (The overall trellis encoder and the individual 12 encoder are both referenced as 108.) The code interleaving is accomplished by encoding symbols (0, 12, 24, 36 . . . ) as one group, symbols (1, 13, 25, 37, . . . ) as a second group, symbols (2, 14, 26, 38, . . . ) as a third group, and so on for a total of 12 groups.
In creating serial bits from parallel bytes, the MSB is sent out first: (7, 6, 5, 4, 3, 2, 1, 0). The MSB is precoded (7, 5, 3, 1) and the LSB is feedback convolutional encoded (6, 4, 2, 0). Standard four-state optimal Ungerboeck codes shall be used for the encoding. The trellis code utilizes the four-state feedback encoder. The trellis code and precoder intrasegment interleaver feeds the symbol mapper. Data bytes are fed from the byte interleaver 106 to the trellis encoder 108 and precoder, and they are processed as whole bytes by each of the twelve encoders 108. Each byte produces four symbols from a single encoder 108. The value of 1.25 is added to all these nominal levels after the bit-to-symbol mapping function for the purpose of creating a small pilot carrier, discussed hereafter.
Following the trellis encoder 108 the output multiplexer 110 advances by four symbols on each segment boundary. However, the state of the trellis encoder 108 shall not be advanced. The data coming out of the multiplexer 110 shall follow normal ordering from encoder 0 through 11 of the trellis encoder 108 for the first segment of the frame, but on the second segment the order changes and symbols are read from encoders 4 through 11, and then 0 through 3 of the trellis encoder 108. The third segment reads from encoder 8 through 11 and then encoder 0 through 7 of the trellis encoder 108. This three-segment pattern shall repeat through the 312 data segments of the frame. After the data segment sync 112 is inserted, the ordering of the data symbols is such that symbols from each encoder 108 occur at a spacing of twelve symbols.
A complete conversion of parallel bytes to serial bits needs 828 bytes to produce 6624 bits. Data symbols are created from 2 bits sent in MSB order, so a complete conversion operation yields 3312 data symbols, which corresponds to 4 segments of 828 data symbols. 3312 data symbols divided by 12 trellis encoders 108 gives 276 symbols per trellis encoder 108. 276 symbols divided by 4 symbols per byte gives 69 bytes per trellis encoder 108. The conversion starts with the first segment of the field and proceeds with groups of 4 segments until the end of the field. The 312 segments per field divided by 4 gives 78 conversion operations per field. During segment sync 112 the input to 4 encoders 108 is skipped and the trellis encoders 108 cycle with no input. The input is held until the next multiplex cycle and then fed to the correct trellis encoder 108.
The encoded trellis data shall be passed through a multiplexer 110 that inserts the various synchronization signals (data segment sync 112 and data field sync 114). A two-level (binary) four-symbol data segment sync 112 is inserted into the 8-level digital data stream at the beginning of each data segment. (The MPEG sync byte shall be replaced by data segment sync 112.)
A complete data segment comprises 832 symbols: 4 symbols for data segment sync 112, and 828 data plus parity symbols. The data segment sync 112 is binary (2-level). The same sync pattern occurs regularly at 77.3 μs intervals, and is the only signal repeating at this rate. Unlike the data, the four symbols for the data segment sync 112 are not Reed-Solomon, trellis encoded or interleaved. The data segment sync 112 pattern is a 1001 pattern.
The data are not only divided into data segments, but also into data fields, each comprising 313 segments. Each data field (24.2 ms) begins with one complete data segment of data field sync 114. Each symbol represents one bit of data (2-level). Like the data segment sync 112, the field sync 114 is not Reed-Solomon, trellis encoded or interleaved.
Following the multiplexer 110, a small in-phase pilot signal 300 is added to the data signal in the pilot insertion block 116. The frequency of the pilot signal 300 shall be the same as the suppressed-carrier frequency as shown in
Following the pilot insertion block 116 (and optional pre-equalizer filter 118), the VSB modulator 120 receives the 10.76 Msymbols/s, 8-level trellis encoded composite data signal (with the pilot and sync signals added). The ATV system performance is based on a linear phase raised cosine Nyquist filter response in the concatenated transmitter 100 and receiver, as shown in
2. Layered Modulation in Advanced Television Systems Committee (ATSC) Applications
Embodiments of the present invention apply the principle of layered modulation, as detailed in U.S. Utility application Ser. No. 09/844,401, filed Apr. 27, 2001, by Ernest C. Chen, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” which is incorporated by reference herein, to the 8-VSB terrestrial broadcast format of the ATSC standard described above.
Applying layered modulation to the 8-VSB signal, embodiments of the present invention introduce a new signal with a reduced power (a lower layer VSB signal) transmitted simultaneously over the legacy 8-VSB signal. The legacy signal can now be viewed as an upper layer signal in a layered modulation system. Existing receivers will continue to receive the upper layer signal without being “aware” of the presence of the new signal; the lower layer signal is ignored as “noise” in legacy receivers. However, new layered modulation VSB receivers can receive and process both the new lower layer signal and the legacy signal. The result is an increased throughput for the new layered modulation VSB receivers. Although layered modulation increase spectral efficiency over the allocated bandwidth, it generally requires a higher carrier to noise ratio (CNR) for the legacy VSB signal in order to insert the lower layer VSB signal.
As terrestrial broadcasting inherently carries a higher CNR at closer distances to the transmitter (following 1/R2 rule and an antenna receive pattern), in some embodiments, the new lower layer VSB signal may be designed with a shorter maximum range than that of the legacy VSB signal, if it is desirable to limit the impact of the new VSB service on the maximum range performance of the legacy VSB service. This can be achieved through several techniques. For example, one technique is to reduce the height of the transmit antenna, resulting in a shorter horizon range. Another techniques is to point the antenna with a larger depression angle, avoiding most energy from the lower layer signal into the legacy signal at long ranges. Still another technique is to generally re-shape the antenna elevation pattern to provide the desirable power separation between the legacy VSB signal and the new lower layer VSB signal and minimize the impact on the legacy signal operation.
It should also be noted that the lower layer signal may be implemented with other modulation formats, e.g. QPSK, so long as the signal remains contained within the designated bandwidth.
In the examples discussed below, the antennas transmitting the respective upper and lower layer signals are assumed to point to their respective radio horizons for maximum range performance. For simplicity in the analysis, the near-in antenna gain pattern is assumed to be quadratic in dB as a function of angle from the antenna boresight. As shown in
RU≈√{square root over (2RehU)} (1)
RL≈√{square root over (2RehL)} (2)
rv=hU+Re(1−cos θi) (3)
rh=Re sin θi (4)
Thus, the elevation angle to the bore-sight αi (as measured from the horizontal line through the antenna) can be calculated for the ground point P at geocentric angle θi. The antenna bore-sight angle αi can be used to calculate the angle off the bore-sight and therefore the antenna gain at Point P.
Thus, the layered signal, comprising both the upper layer signal 704A and the lower layer signal 704B, is transmitted only out to the selective range limit 716B (the second antenna 706B range of the lower layer signal 704B). Within this range limit 716B, a first legacy antenna 708A and legacy receiver 712A can receive and decode the upper layer legacy signal 704A from the layered signal (ignoring the lower layer signal 704B as noise). In addition, a layered signal antenna 710 and layered signal receiver 714 can receive and decode both the upper layer signal 704A and the lower layer signal 704B within this selective range limit 716B. Beyond this selective range limit 716B and out to the upper layer signal rang limit 716A, a second legacy antenna 708B and legacy receiver 708B can still receive and decode the upper layer signal 704A.
Some further design factors should be considered in order to maximize the overall range performance of the system 700. In some embodiments of the invention the lower layer antenna height can be reduced. This results in a shortened horizon range, which avoids potential performance impact on the long range upper layer signal within the horizon of the lower layer signal antenna as related to the discussion in the examples of
In order for the subtraction to leave a suitable lower layer signal 704B, the upper layer legacy signal 704A must be precisely reproduced. The modulated signal may have been distorted, for example, by amplifier non-linearity in transmission. These and other distortion effects can be estimated from the received signal after the fact or from amplifier characteristics which can be downloaded into the receiver in AM-AM and/or AM-PM maps 818, which are used to eliminate the distortion.
A subtractor 812 then subtracts the idealized upper layer signal from the stable demodulated signal 820. This leaves the lower layer signal 704B. The subtractor includes a buffer or delay function to retain the stable demodulated signal 820 while the idealized upper layer signal 704A is being reconstructed. The lower layer signal 704B is demodulated 810 and decoded 808 according to its signal format.
This concludes the description including the preferred embodiments of the present invention. The foregoing description of 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 apparatus and method 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.
This application claims the benefit of U.S. Provisional Patent Application No. 60/421,327, entitled “LAYERED MODULATION FOR ATSC APPLICATIONS,” by Ernest C. Chen, filed Oct. 25, 2002. This application is also a continuation-in-part application of the following co-pending and commonly-assigned U.S. utility patent application, which applications is incorporated by reference herein: U.S. Utility application Ser. No. 09/844,401, filed Apr. 27, 2001, by Ernest C. Chen, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS.” Application Ser. No. 11/653,517, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Jan. 16, 2007, by Ernest C. Chen, which is a continuation of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/165,710, entitled “SATELLITE TWTA ON-LINE NON-LINEARITY MEASUREMENT,” filed on Jun. 7, 2002, by Ernest C. Chen, which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/236,414, entitled “SIGNAL, INTERFERENCE AND NOISE POWER MEASUREMENT,” filed on Sep. 6, 2002, by Ernest C. Chen and Chinh Tran, which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/913,927, entitled “CARRIER TO NOISE RATIO ESTIMATIONS FROM A RECEIVED SIGNAL,” filed on Aug. 5, 2004, by Ernest C. Chen, which is a continuation in part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 11/619,173, entitled “PREPROCESSING SIGNAL LAYERS IN LAYERED MODULATION DIGITAL SIGNAL SYSTEM TO USE LEGACY RECEIVERS,” filed Jan. 2, 2007, which is a continuation of application Ser. No. 10/068,039, entitled “PREPROCESSING SIGNAL LAYERS IN LAYERED MODULATION DIGITAL SIGNAL SYSTEM TO USE LEGACY RECEIVERS,” filed on Feb. 5, 2002, by Ernest C. Chen, Tiffany S. Furuya, Philip R. Hilmes, and Joseph Santoru now issued as U.S. Pat. No. 7,245,671, which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/693,421, entitled “FAST ACQUISITION OF TIMING AND CARRIER FREQUENCY FROM RECEIVED SIGNAL,” filed on Oct. 24, 2003, by Ernest C. Chen, now issued as U.S. Pat. No. 7,151,807, which claims priority to Provisional Patent Application Ser. No. 60/421,292, filed Oct. 25, 2002, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/692,491, entitled “ONLINE OUTPUT MULTIPLEXER FILTER MEASUREMENT,” filed on Oct. 24, 2003, by Ernest C. Chen, which claims priority to Provisional Patent Application 60/421,290, filed Oct. 25, 2002, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27,2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 11/603,776, entitled “DUAL LAYER SIGNAL PROCESSING IN A LAYERED MODULATION DIGITAL SIGNAL SYSTEM,” filed on Nov. 22, 2006, by Ernest C. Chen, Tiffany S. Furaya, Philip R. Hilmes, and Joseph Santoru, which is a continuation of application Ser. No. 10/068,047, entitled “DUAL LAYER SIGNAL PROCESSING IN A LAYERED MODULATION DIGITAL SIGNAL SYSTEM;” filed on Feb. 5, 2002, by Ernest C. Chen, Tiffany S. Furaya, Philip R. Hilmes, and Joseph Santoru, now issued as U.S. Pat. No. 7,173,981, which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/691,032, entitled “UNBLIND EQUALIZER ARCHITECTURE FOR DIGITAL COMMUNICATION SYSTEMS,” filed on Oct. 22, 2003, by Weizheng W. Wang, Tung-Sheng Lin, Ernest C. Chen, and William C. Lindsey, which claims priority to Provisional Patent Application Ser. No. 60/421,329, filed Oct. 25, 2002, and which is a continuation-in-part of application Ser. No.09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/962,346, entitled “COHERENT AVERAGING FOR MEASURING TRAVELING WAVE TUBE AMPLIFIER NONLINEARITY,” filed on Oct. 8, 2004, by Ernest C. Chen, which claims priority to Provisional Patent Application Ser. No. 60/510,368, filed October 10, 2003, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 11/655,001, entitled “AN OPTIMIZATION TECHNIQUE FOR LAYERED MODULATION,” filed on Jan. 18, 2007, by Weizheng W. Wang, Guancai Zhou, Tung-Sheng Lin, Ernest C. Chen, Joseph Santoru, and William Lindsey, which claims priority to Provisional Patent Application 60/421,293, filed Oct. 25, 2002, and which is a continuation of Application Ser. No. 10/693,140, entitled “OPTIMIZATION TECHNIQUE FOR LAYERED MODULATION,” filed on Oct. 24, 2003, by Weizheng W. Wang, Guancai Zhou, Tung-Sheng Lin, Ernest C. Chen, Joseph Santoru, and William Lindsey, now issued as U.S. Pat. No. 7,184,489, which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 11/656,662, entitled “EQUALIZERS FOR LAYERED MODULATION AND OTHER SIGNALS,” filed on Jan. 22, 2007, by Ernest C. Chen, Tung-Sheng Lin, Weizheng W. Wang, and William C. Lindsey, which claims priority to Provisional Patent Application 60/421,241, filed Oct. 25, 2002, and which is a continuation of application Ser. No. 10/691,133, entitled “EQUALIZERS FOR LAYERED MODULATED AND OTHER SIGNALS,” filed on Oct. 22, 2003, by Ernest C. Chen, Tung-Sheng Lin, Weizheng W. Wang, and William C. Lindsey, now issued as U.S. Pat. No. 7,184,473, which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/961,579, entitled “EQUALIZATION FOR TWTA NONLINEARITY MEASUREMENT” filed on Oct. 8, 2004, by Ernest C. Chen, which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/532,632, entitled “LOWER COMPLEXITY LAYERED MODULATION SIGNAL PROCESSOR,” filed on Apr. 25, 2005, by Ernest C. Chen, Weizheng W. Wang, Tung-Sheng Lin, Guangcai Zhou, and Joseph Santoru, which is a National Stage Application of PCT US03/32264, filed Oct. 10, 2003, which claims priority to Provisional Patent Application 60/421,331, entitled “LOWER COMPLEXITY LAYERED MODULATION SIGNAL PROCESSOR,” filed Oct. 25, 2002, by Ernest C. Chen, Weizheng W. Wang, Tung-Sheng Lin, Guangcai Zhou, and Joseph Santoru, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/532,631, entitled “FEEDER LINK CONFIGURATIONS TO SUPPORT LAYERED MODULATION FOR DIGITAL SIGNALS” filed on Apr. 25, 2005, by Paul R. Anderson, Joseph Santoru and Ernest C. Chen, which is a National Phase Application of PCT US03/33255, filed Oct. 20, 2003, which claims priority to Provisional Patent Application 60/421,328, entitled “FEEDER LINK CONFIGURATIONS TO SUPPORT LAYERED MODULATION FOR DIGITAL SIGNALS,” filed Oct. 25, 2002, by Paul R. Anderson, Joseph Santoru and Ernest C. Chen, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/532,619, entitled “MAXIMIZING POWER AND SPECTRAL EFFICIENCIES FOR LAYERED AND CONVENTIONAL MODULATIONS,” filed on Apr. 25, 2005, by Ernest C. Chen, which is a National Phase Application of PCT Application US03/32800, filed Oct. 16, 2003, which claims priority to Provisional Patent Application 60/421,288, entitled “MAXIMIZING POWER AND SPECTRAL EFFICIENCIES FOR LAYERED AND CONVENTIONAL MODULATION,” filed Oct. 25, 2002, by Ernest C. Chen and which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524, Application Ser. No. 10/532,524, entitled “AMPLITUDE AND PHASE MATCHING FOR LAYERED MODULATION RECEPTION,” filed on Apr. 25, 2005, by Ernest C. Chen, Jeng-Hong Chen, Kenneth Shum, and Joungheon Oh, which is a National Phase Application of PCT Application US03/31199, filed Oct. 3, 2003, which claims priority to Provisional Patent Application 60/421,332, entitled “AMPLITUDE AND PHASE MATCHING FOR LAYERED MODULATION RECEPTION” filed Oct. 25, 2002, by Ernest C. Chen, Jeng-Hong Chen, Kenneth Shum, and Joungheon Oh, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524, and also claims priority to; Application Ser. No. 10/532,582, entitled “METHOD AND APPARATUS FOR TAILORING CARRIER POWER REQUIREMENTS ACCORDING TO AVAILABILITY IN LAYERED MODULATION SYSTEMS,” filed on Apr. 25, 2005, by Ernest C. Chen, Paul R. Anderson and Joseph Santoru, now issued as U.S. Pat. No. 7,173,977, which is a National Stage Application of PCT Application US03/32751, filed Oct. 15, 2003, which claims priority to Provisional Patent Application 60/421,333, entitled “METHOD AND APPARATUS FOR TAILORING CARRIER POWER REQUIREMENTS ACCORDING TO AVAILABILITY IN LAYERED MODULATION SYSTEMS” filed Oct. 25, 2002, by Ernest C. Chen, Paul R. Anderson and Joseph Santoru, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/532,509, entitled “ESTIMATING THE OPERATING POINT ON A NONLINEAR TRAVELING WAVE TUBE AMPLIFIER,” filed on Apr. 25, 2005, by Ernest C. Chen and Shamik Maitra, now issued as U.S. Pat. No. 7,230,480, which is a National Stage Application of PCT Application US03/33130 filed Oct. 17, 2003, and which claims priority to Provisional Patent Application 60/421,289, entitled “ESTIMATING THE OPERATING POINT ON A NONLINEAR TRAVELING WAVE TUBE AMPLIFIER,” filed Oct. 25, 2002, by Ernest C. Chen and Shamik Maitra, and which is a continuation-in-part of application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/519,322, entitled “IMPROVING HIERARCHICAL 8PSK PERFORMANCE,” filed on Dec. 23, 2004 by Ernest C. Chen and Joseph Santoru, which is a National Stage Application of PCT US03/020862 filed Jul. 1, 2003, which claims priority to Provisional Patent Application 60/392,861, filed Jul. 1, 2002 and Provisional Patent Application 60/392,860, filed Jul. 1, 2002, and which is also related to application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; Application Ser. No. 10/519,375, entitled “METHOD AND APPARATUS FOR LAYERED MODULATION,” filed on Jul. 3, 2003, by Ernest C. Chen and Joseph Santoru, which is a National Stage Application of PCT US03/20847, filed Jul. 3, 2003, which claims priority to Provisional Patent Application 60/393,437 filed Jul. 3, 2002, and which is related to Application Ser. No. 09/844,401, entitled “LAYERED MODULATION FOR DIGITAL SIGNALS,” filed on Apr. 27, 2001, by Ernest C. Chen, now issued as U.S. Pat. No. 7,209,524; and Application Ser. No. 10/692,539, entitled “ON-LINE PHASE NOISE MEASUREMENT FOR LAYERED MODULATION”, filed Oct. 24, 2003, by Ernest C. Chen, which claims priority from Provisional Patent Application 60/421,291, filed Oct. 25, 2002, entitled “ON-LINE PHASE NOISE MEASUREMENT FOR LAYERED MODULATION”.
Number | Name | Date | Kind |
---|---|---|---|
3076180 | Havens et al. | Jan 1963 | A |
3383598 | Sanders | May 1968 | A |
3878468 | Falconer et al. | Apr 1975 | A |
3879664 | Monsen | Apr 1975 | A |
3974449 | Falconer | Aug 1976 | A |
4039961 | Ishio et al. | Aug 1977 | A |
4068186 | Sato et al. | Jan 1978 | A |
4213095 | Falconer | Jul 1980 | A |
4253184 | Gitlin et al. | Feb 1981 | A |
4283684 | Satoh | Aug 1981 | A |
4384355 | Werner | May 1983 | A |
RE31351 | Falconer | Aug 1983 | E |
4416015 | Gitlin | Nov 1983 | A |
4422175 | Bingham et al. | Dec 1983 | A |
4484337 | Leclert et al. | Nov 1984 | A |
4500984 | Shimbo et al. | Feb 1985 | A |
4519084 | Langseth | May 1985 | A |
4594725 | Desperben et al. | Jun 1986 | A |
4628507 | Otani | Dec 1986 | A |
4637017 | Assal et al. | Jan 1987 | A |
4647873 | Beckner et al. | Mar 1987 | A |
4654863 | Belfield et al. | Mar 1987 | A |
4670789 | Plume | Jun 1987 | A |
4709374 | Farrow | Nov 1987 | A |
4800573 | Cupo | Jan 1989 | A |
4829543 | Borth et al. | May 1989 | A |
4835790 | Yoshida et al. | May 1989 | A |
4847864 | Cupo | Jul 1989 | A |
4860315 | Hosoda et al. | Aug 1989 | A |
4878030 | Vincze | Oct 1989 | A |
4896369 | Adams et al. | Jan 1990 | A |
4918708 | Pottinger et al. | Apr 1990 | A |
4993047 | Moffat et al. | Feb 1991 | A |
5043734 | Niho | Aug 1991 | A |
5088110 | Bonnerot et al. | Feb 1992 | A |
5111155 | Keate et al. | May 1992 | A |
5121414 | Levine et al. | Jun 1992 | A |
5199047 | Koch | Mar 1993 | A |
5206889 | Unkrich | Apr 1993 | A |
5221908 | Katz et al. | Jun 1993 | A |
5229765 | Gardner | Jul 1993 | A |
5233632 | Baum et al. | Aug 1993 | A |
5237292 | Chethik | Aug 1993 | A |
5285480 | Chennakeshu et al. | Feb 1994 | A |
5317599 | Obata | May 1994 | A |
5329311 | Ward et al. | Jul 1994 | A |
5337014 | Najle et al. | Aug 1994 | A |
5353307 | Lester et al. | Oct 1994 | A |
5412325 | Meyers | May 1995 | A |
5430770 | Abbey | Jul 1995 | A |
5450623 | Yokoyama et al. | Sep 1995 | A |
5467197 | Hoff | Nov 1995 | A |
5471508 | Koslov | Nov 1995 | A |
5493307 | Tsujimoto | Feb 1996 | A |
5513215 | Marchetto et al. | Apr 1996 | A |
5555257 | Dent | Sep 1996 | A |
5577067 | Zimmerman | Nov 1996 | A |
5577087 | Furuya | Nov 1996 | A |
5579344 | Namekata | Nov 1996 | A |
5581229 | Hunt | Dec 1996 | A |
5592481 | Wiedeman et al. | Jan 1997 | A |
5602868 | Wilson | Feb 1997 | A |
5603084 | Henry et al. | Feb 1997 | A |
5606286 | Bains | Feb 1997 | A |
5608331 | Newberg et al. | Mar 1997 | A |
5625640 | Palmer et al. | Apr 1997 | A |
5642358 | Dent | Jun 1997 | A |
5644592 | Divsalar et al. | Jul 1997 | A |
5648955 | Jensen et al. | Jul 1997 | A |
5732113 | Schmidl et al. | Mar 1998 | A |
5793818 | Claydon et al. | Aug 1998 | A |
5815531 | Dent | Sep 1998 | A |
5819157 | Ben-Efraim et al. | Oct 1998 | A |
5828710 | Beale | Oct 1998 | A |
5848060 | Dent | Dec 1998 | A |
5870439 | Ben-Efraim et al. | Feb 1999 | A |
5870443 | Rahnema | Feb 1999 | A |
5937004 | Fasulo, II et al. | Aug 1999 | A |
5940025 | Koehnke et al. | Aug 1999 | A |
5940750 | Wang | Aug 1999 | A |
5946625 | Hassan et al. | Aug 1999 | A |
5952834 | Buckley | Sep 1999 | A |
5956373 | Goldston et al. | Sep 1999 | A |
5960040 | Cai et al. | Sep 1999 | A |
5963845 | Floury et al. | Oct 1999 | A |
5966048 | Thompson | Oct 1999 | A |
5966186 | Shigihara et al. | Oct 1999 | A |
5966412 | Ramaswamy | Oct 1999 | A |
5970098 | Herzberg | Oct 1999 | A |
5970156 | Hummelgaard et al. | Oct 1999 | A |
5970429 | Martin | Oct 1999 | A |
5978652 | Burr et al. | Nov 1999 | A |
5987068 | Cassia et al. | Nov 1999 | A |
5987069 | Furukawa et al. | Nov 1999 | A |
5995832 | Mallinckrodt | Nov 1999 | A |
5999793 | Ben-Efraim et al. | Dec 1999 | A |
6008692 | Escartin | Dec 1999 | A |
6018556 | Janesch et al. | Jan 2000 | A |
6021159 | Nakagawa | Feb 2000 | A |
6028894 | Oishi et al. | Feb 2000 | A |
6032026 | Seki et al. | Feb 2000 | A |
6034952 | Dohi et al. | Mar 2000 | A |
6049566 | Saunders et al. | Apr 2000 | A |
6052586 | Karabinis | Apr 2000 | A |
6055278 | Ho et al. | Apr 2000 | A |
6061393 | Tsui et al. | May 2000 | A |
6072841 | Rahnema | Jun 2000 | A |
6084919 | Kleider et al. | Jul 2000 | A |
6104747 | Jalloul et al. | Aug 2000 | A |
6108374 | Balachandran et al. | Aug 2000 | A |
6125148 | Frodigh et al. | Sep 2000 | A |
6125260 | Wiedeman et al. | Sep 2000 | A |
6128357 | Lu et al. | Oct 2000 | A |
6131013 | Bergstrom et al. | Oct 2000 | A |
6134282 | Ben-Efraim et al. | Oct 2000 | A |
6140809 | Doi | Oct 2000 | A |
6141534 | Snell et al. | Oct 2000 | A |
6144708 | Maruyama | Nov 2000 | A |
6166601 | Shalom et al. | Dec 2000 | A |
6177836 | Young et al. | Jan 2001 | B1 |
6178158 | Suzuki et al. | Jan 2001 | B1 |
6188717 | Kaiser et al. | Feb 2001 | B1 |
6192088 | Aman et al. | Feb 2001 | B1 |
6212360 | Fleming et al. | Apr 2001 | B1 |
6219095 | Zhang et al. | Apr 2001 | B1 |
6246717 | Chen et al. | Jun 2001 | B1 |
6249180 | Maalej et al. | Jun 2001 | B1 |
6266534 | Raith et al. | Jul 2001 | B1 |
6272679 | Norin | Aug 2001 | B1 |
6275678 | Bethscheider et al. | Aug 2001 | B1 |
6297691 | Anderson et al. | Oct 2001 | B1 |
6304594 | Salinger | Oct 2001 | B1 |
6307435 | Nguyen et al. | Oct 2001 | B1 |
6314441 | Raghunath | Nov 2001 | B1 |
6320464 | Suzuki et al. | Nov 2001 | B1 |
6320919 | Khyrallah et al. | Nov 2001 | B1 |
6325332 | Cellier et al. | Dec 2001 | B1 |
6330336 | Kasama | Dec 2001 | B1 |
6333924 | Porcelli et al. | Dec 2001 | B1 |
6335951 | Cangiani et al. | Jan 2002 | B1 |
6366309 | Siegle | Apr 2002 | B1 |
6369648 | Kirkman | Apr 2002 | B1 |
6377116 | Mattsson et al. | Apr 2002 | B1 |
6389002 | Schilling | May 2002 | B1 |
6411659 | Liu et al. | Jun 2002 | B1 |
6411797 | Estinto | Jun 2002 | B1 |
6426822 | Winter et al. | Jul 2002 | B1 |
6429740 | Nguyen et al. | Aug 2002 | B1 |
6433835 | Hartson et al. | Aug 2002 | B1 |
6452977 | Goldston et al. | Sep 2002 | B1 |
6477398 | Mills | Nov 2002 | B1 |
6501804 | Dietmar et al. | Dec 2002 | B1 |
6515713 | Nam | Feb 2003 | B1 |
6522683 | Smee et al. | Feb 2003 | B1 |
6529715 | Kitko et al. | Mar 2003 | B1 |
6535497 | Raith | Mar 2003 | B1 |
6535801 | Geier et al. | Mar 2003 | B1 |
6574235 | Arslan et al. | Jun 2003 | B1 |
6597750 | Knutson et al. | Jul 2003 | B1 |
6657978 | Millman | Dec 2003 | B1 |
6661761 | Hayami et al. | Dec 2003 | B2 |
6678336 | Katoh et al. | Jan 2004 | B1 |
6700442 | Ha | Mar 2004 | B2 |
6718184 | Aiken et al. | Apr 2004 | B1 |
6731622 | Frank et al. | May 2004 | B1 |
6731700 | Yakhnich et al. | May 2004 | B1 |
6741662 | Francos et al. | May 2004 | B1 |
6745050 | Forsythe et al. | Jun 2004 | B1 |
6772182 | McDonald et al. | Aug 2004 | B1 |
6775521 | Chen | Aug 2004 | B1 |
6795496 | Soma et al. | Sep 2004 | B1 |
6809587 | Ghannouchi et al. | Oct 2004 | B2 |
6892068 | Karabinis et al. | May 2005 | B2 |
6922436 | Porat et al. | Jul 2005 | B1 |
6922439 | Yamaguchi et al. | Jul 2005 | B2 |
6934314 | Harles et al. | Aug 2005 | B2 |
6947741 | Beech et al. | Sep 2005 | B2 |
6956841 | Stahle et al. | Oct 2005 | B1 |
6956924 | Linsky et al. | Oct 2005 | B2 |
6970496 | Ben-Bassat et al. | Nov 2005 | B1 |
6980609 | Ahn | Dec 2005 | B1 |
6990627 | Uesugi et al. | Jan 2006 | B2 |
6999510 | Batruni | Feb 2006 | B2 |
7041406 | Schuler et al. | May 2006 | B2 |
7073116 | Settle et al. | Jul 2006 | B1 |
7079585 | Settle et al. | Jul 2006 | B1 |
7154958 | Dabak et al. | Dec 2006 | B2 |
7161931 | Li et al. | Jan 2007 | B1 |
7173981 | Chen et al. | Feb 2007 | B1 |
7184473 | Chen et al. | Feb 2007 | B2 |
7209524 | Chen | Apr 2007 | B2 |
7230992 | Walker et al. | Jun 2007 | B2 |
7239876 | Johnson et al. | Jul 2007 | B2 |
7251291 | Dubuc et al. | Jul 2007 | B1 |
7263119 | Hsu et al. | Aug 2007 | B1 |
20010012322 | Nagaoka et al. | Aug 2001 | A1 |
20010016926 | Riggle | Aug 2001 | A1 |
20010024479 | Samarasooriya | Sep 2001 | A1 |
20010055295 | Akiyama et al. | Dec 2001 | A1 |
20020006795 | Norin et al. | Jan 2002 | A1 |
20020051435 | Giallorenzi et al. | May 2002 | A1 |
20020071506 | Lindquist et al. | Jun 2002 | A1 |
20020082792 | Bourde et al. | Jun 2002 | A1 |
20020136327 | El-Gamal et al. | Sep 2002 | A1 |
20020154705 | Walton et al. | Oct 2002 | A1 |
20020158619 | Chen | Oct 2002 | A1 |
20020172296 | Pilcher | Nov 2002 | A1 |
20020176516 | Jeske et al. | Nov 2002 | A1 |
20030002471 | Crawford et al. | Jan 2003 | A1 |
20030043941 | Johnson et al. | Mar 2003 | A1 |
20030072385 | Dragonetti | Apr 2003 | A1 |
20030138037 | Kaku et al. | Jul 2003 | A1 |
20030138040 | Rouphael et al. | Jul 2003 | A1 |
20030147472 | Bach et al. | Aug 2003 | A1 |
20030185310 | Ketchum et al. | Oct 2003 | A1 |
20030194022 | Hammons et al. | Oct 2003 | A1 |
20040110467 | Wang | Jun 2004 | A1 |
20040137863 | Walton et al. | Jul 2004 | A1 |
20040146014 | Hammons et al. | Jul 2004 | A1 |
20040146296 | Gerszberg et al. | Jul 2004 | A1 |
20040196935 | Nieto | Oct 2004 | A1 |
20050008100 | Chen | Jan 2005 | A1 |
20050037724 | Walley et al. | Feb 2005 | A1 |
20060013333 | Chen | Jan 2006 | A1 |
20060056541 | Chen et al. | Mar 2006 | A1 |
20070011716 | Koslov et al. | Jan 2007 | A1 |
20070121718 | Wang et al. | May 2007 | A1 |
Number | Date | Country |
---|---|---|
3642213 | Dec 1986 | DE |
0115218 | Aug 1984 | EP |
0222076 | Aug 1986 | EP |
0238822 | Sep 1987 | EP |
0356096 | Feb 1990 | EP |
0491668 | Jun 1992 | EP |
0874474 | Oct 1998 | EP |
0929164 | Jul 1999 | EP |
1011245 | Jun 2000 | EP |
1335512 | Aug 2003 | EP |
2696295 | Apr 1994 | FR |
2724522 | Mar 1996 | FR |
2-5631 | Jan 1990 | JP |
2-95033 | Apr 1990 | JP |
03139027 | Jun 1991 | JP |
5-41683 | Feb 1993 | JP |
5-114878 | May 1993 | JP |
5-252084 | Sep 1993 | JP |
07-038615 | Feb 1995 | JP |
2001-244832 | Sep 2001 | JP |
2002118611 | Apr 2002 | JP |
WO 9900957 | Jan 1999 | WO |
WO 9920001 | Apr 1999 | WO |
WO 9923718 | May 1999 | WO |
1999033203 | Jul 1999 | WO |
0079708 | Dec 2000 | WO |
0079753 | Dec 2000 | WO |
0113532 | Feb 2001 | WO |
WO 0119013 | Mar 2001 | WO |
WO 0139456 | May 2001 | WO |
WO 02073817 | Sep 2002 | WO |
WO 2005074171 | Aug 2005 | WO |
WO 2005086444 | Sep 2005 | WO |
Number | Date | Country | |
---|---|---|---|
20040091059 A1 | May 2004 | US |
Number | Date | Country | |
---|---|---|---|
60421327 | Oct 2002 | US |