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公开(公告)号：IE922390A1
公开(公告)日：1993-01-27
申请号：IE922390
申请日：1992-07-23
Applicant: GEN INSTRUMENT CORP
Inventor： PAIK WOO H , LERY SCOTT A , HEEGARD CHRIS , KRAUSE EDWARD A , HELLER JERROLD A
IPC: H03M7/30 , F16D13/58 , G06T9/00 , H03M7/40 , H03M13/23 , H03M13/25 , H03M13/27 , H03M13/29 , H04L1/00 , H04L27/00 , H04L27/32 , H04L27/34 , H04N7/015 , H04N7/24 , H04N7/26 , H04N7/66 , H04N19/00 , H04N21/2383 , H04N21/438 , H04N7/13 , H04N7/00
Abstract: Coded modulation schemes based on codes for QPSK modulation are directly incorporated into QAM based modulation systems, forming trellis coded QAM, to provide a practical coding structure that is both efficient in bandwidth and data reliability. Concatenated coding with QPSK based trellis coding and symbol error correcting coding is used. In an encoder (Fig. 2), an N-bit QAM constellation pattern (80) is divided into four subsets, each including N/4 symbol points of the constellation pattern. A two-bit QPSK codeword (92) is assigned to each of the four subsets (82, 84, 86, 88). A symbol to be transmitted is first encoded using an outer error correcting encoding algorithm, such as a Reed-Solomon code (12). Part of the symbol is then encoded (48) with an inner code that comprises a rate 1/2 trellis encoding algorithm to provide a QPSK codeword, which is mapped (50) with the remaining bits of the symbol to provide a modulation function, wherein the remaining bits (94) correlate the symbol with one of the symbol points included in the subset defined by the QPSK codeword. At a receiver (Fig. 3), the recovered modulation function is pruned (62) to provide a set of metrics (66) corresponding to the subsets and to provide a plurality of conditional determinations of the constellation point identified by the remaining bits. The metrics are used in a rate 1/2 trellis decoder (68) to recover a first bit that is encoded using a rate 1/2 encoding algorithm to recreate the QPSK codeword. One of a plurality of the conditional determinations is selected in response to the recreated codeword. The selected conditional determination is combined with the recovered first bit to provide a decoded output that is further decoded using a symbol error correcting algorithm such as a Reed-Solomon code (36).
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公开(公告)号：IE922389A1
公开(公告)日：1993-01-27
申请号：IE922389
申请日：1992-07-23
Applicant: GEN INSTRUMENT CORP
Inventor： PAIK WOO H , LERY SCOTT A , HEEGARD CHRIS
IPC: H03M7/30 , F16D13/58 , G06T9/00 , H03M7/40 , H03M13/23 , H03M13/25 , H03M13/27 , H03M13/29 , H04L1/00 , H04L27/00 , H04L27/32 , H04L27/34 , H04N7/015 , H04N7/24 , H04N7/26 , H04N7/66 , H04N19/00 , H04N21/2383 , H04N21/438 , H04N7/13 , H04N7/08 , H03M13/00
Abstract: Coded modulation schemes based on codes for QPSK modulation are directly incorporated into QAM based modulation systems, forming trellis coded QAM, to provide a practical coding structure that is both efficient in bandwidth and data reliability. Concatenated coding with QPSK based trellis coding and symbol error correcting coding is used. In an encoder (Fig. 2), an N-bit QAM constellation pattern (80) is divided into four subsets, each including N/4 symbol points of the constellation pattern. A two-bit QPSK codeword (92) is assigned to each of the four subsets (82, 84, 86, 88). A symbol to be transmitted is first encoded using an outer error correcting encoding algorithm, such as a Reed-Solomon code (12). Part of the symbol is then encoded (48) with an inner code that comprises a rate 1/2 trellis encoding algorithm to provide a QPSK codeword, which is mapped (50) with the remaining bits of the symbol to provide a modulation function, wherein the remaining bits (94) correlate the symbol with one of the symbol points included in the subset defined by the QPSK codeword. At a receiver (Fig. 3), the recovered modulation function is pruned (62) to provide a set of metrics (66) corresponding to the subsets and to provide a plurality of conditional determinations of the constellation point identified by the remaining bits. The metrics are used in a rate 1/2 trellis decoder (68) to recover a first bit that is encoded using a rate 1/2 encoding algorithm to recreate the QPSK codeword. One of a plurality of the conditional determinations is selected in response to the recreated codeword. The selected conditional determination is combined with the recovered first bit to provide a decoded output that is further decoded using a symbol error correcting algorithm such as a Reed-Solomon code (36).
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公开(公告)号：NO309070B1
公开(公告)日：2000-12-04
申请号：NO922926
申请日：1992-07-23
Applicant: GEN INSTRUMENT CORP
Inventor： PAIK WOO H , LERY SCOTT A , HEEGARD CHRIS
IPC: H03M7/30 , F16D13/58 , G06T9/00 , H03M7/40 , H03M13/23 , H03M13/25 , H03M13/27 , H03M13/29 , H04L1/00 , H04L27/00 , H04L27/32 , H04L27/34 , H04N7/015 , H04N7/24 , H04N7/26 , H04N7/66 , H04N19/00 , H04N21/2383 , H04N21/438
Abstract: Coded modulation schemes based on codes for QPSK modulation are directly incorporated into QAM based modulation systems, forming trellis coded QAM, to provide a practical coding structure that is both efficient in bandwidth and data reliability. Concatenated coding with QPSK based trellis coding and symbol error correcting coding is used. In an encoder (Fig. 2), an N-bit QAM constellation pattern (80) is divided into four subsets, each including N/4 symbol points of the constellation pattern. A two-bit QPSK codeword (92) is assigned to each of the four subsets (82, 84, 86, 88). A symbol to be transmitted is first encoded using an outer error correcting encoding algorithm, such as a Reed-Solomon code (12). Part of the symbol is then encoded (48) with an inner code that comprises a rate 1/2 trellis encoding algorithm to provide a QPSK codeword, which is mapped (50) with the remaining bits of the symbol to provide a modulation function, wherein the remaining bits (94) correlate the symbol with one of the symbol points included in the subset defined by the QPSK codeword. At a receiver (Fig. 3), the recovered modulation function is pruned (62) to provide a set of metrics (66) corresponding to the subsets and to provide a plurality of conditional determinations of the constellation point identified by the remaining bits. The metrics are used in a rate 1/2 trellis decoder (68) to recover a first bit that is encoded using a rate 1/2 encoding algorithm to recreate the QPSK codeword. One of a plurality of the conditional determinations is selected in response to the recreated codeword. The selected conditional determination is combined with the recovered first bit to provide a decoded output that is further decoded using a symbol error correcting algorithm such as a Reed-Solomon code (36).
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公开(公告)号：AT196706T
公开(公告)日：2000-10-15
申请号：AT92112587
申请日：1992-07-23
Applicant: GEN INSTRUMENT CORP
Inventor： PAIK WOO H , LERY SCOTT A , HEEGARD CHRIS
IPC: H03M7/30 , F16D13/58 , G06T9/00 , H03M7/40 , H03M13/23 , H03M13/25 , H03M13/27 , H03M13/29 , H04L1/00 , H04L27/00 , H04L27/32 , H04L27/34 , H04N7/015 , H04N7/24 , H04N7/26 , H04N7/66 , H04N19/00 , H04N21/2383 , H04N21/438 , H04N7/08 , H03M13/00
Abstract: Coded modulation schemes based on codes for QPSK modulation are directly incorporated into QAM based modulation systems, forming trellis coded QAM, to provide a practical coding structure that is both efficient in bandwidth and data reliability. Concatenated coding with QPSK based trellis coding and symbol error correcting coding is used. In an encoder (Fig. 2), an N-bit QAM constellation pattern (80) is divided into four subsets, each including N/4 symbol points of the constellation pattern. A two-bit QPSK codeword (92) is assigned to each of the four subsets (82, 84, 86, 88). A symbol to be transmitted is first encoded using an outer error correcting encoding algorithm, such as a Reed-Solomon code (12). Part of the symbol is then encoded (48) with an inner code that comprises a rate 1/2 trellis encoding algorithm to provide a QPSK codeword, which is mapped (50) with the remaining bits of the symbol to provide a modulation function, wherein the remaining bits (94) correlate the symbol with one of the symbol points included in the subset defined by the QPSK codeword. At a receiver (Fig. 3), the recovered modulation function is pruned (62) to provide a set of metrics (66) corresponding to the subsets and to provide a plurality of conditional determinations of the constellation point identified by the remaining bits. The metrics are used in a rate 1/2 trellis decoder (68) to recover a first bit that is encoded using a rate 1/2 encoding algorithm to recreate the QPSK codeword. One of a plurality of the conditional determinations is selected in response to the recreated codeword. The selected conditional determination is combined with the recovered first bit to provide a decoded output that is further decoded using a symbol error correcting algorithm such as a Reed-Solomon code (36).
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公开(公告)号：DE69329264D1
公开(公告)日：2000-09-28
申请号：DE69329264
申请日：1993-07-03
Applicant: GEN INSTRUMENT CORP
Inventor： PAIK WOO H , FOX JOHN M , LERY SCOTT A
Abstract: An interleaver (34) processes information in a pseudorandom order to provide pseudorandom interleaved data for communication to a deinterleaver (42). The pseudorandom interleaved data is processed at the deinterleaver (42) in a pseudorandom order corresponding to that used at the interleaver (34) means, to recover the original information. The pseudorandom processing at the deinterleaver is synchronized with the pseudorandom processing at the interleaver on a trial and error basis. In one embodiment, full synchronization occurs when a Viterbi decoder (44) receiving data from the deinterleaver has a renormalization rate within a designated threshold and when enough synchronization words are detected in data output from the deinterleaver to meet a predetermined criterion. In another embodiment, a timer is used to initiate a new starting address for the pseudorandom processing at the deinterleaver during successive time intervals. Synchronization is achieved when a start address is found that results in the detection of enough synchronization words in data output from the deinterleaver to meet a predetermined synchronization criterion.
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Patent Agency Ranking
公开(公告)号：NO303898B1
公开(公告)日：1998-09-14
申请号：NO922857
申请日：1992-07-17
Applicant: GEN INSTRUMENT CORP
Inventor： PAIK WOO H , LERY SCOTT A , WU ALLEN
Abstract: Convergence of a complex adaptive equalizer (18) used in digital communications is substantially improved by updating all coefficients of the equalizer during each filter clock cycle. Complex signal data is passed through a plurality of successive delay stages (94) to provide N sets of delayed complex signal data. The product of each set and a complex error signal is obtained (100). Each product is concurrently updated with previous product data for the set to provide N sets of updated complex coefficients for selective input to equalizer filters. In an illustrated embodiment, the updated coefficients are truncated (108) and their gain is adjusted prior to input to the filters (34 ... 34M). The updated coefficients can be multiplexed (110) to provide a clocked stream of coefficient sets for input to the equalizer filters. A VLSI implementation (120) of the equalizer is also disclosed.
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公开(公告)号：DE69316415D1
公开(公告)日：1998-02-26
申请号：DE69316415
申请日：1993-03-16
Applicant: GEN INSTRUMENT CORP
Inventor： PAIK WOO H , LERY SCOTT A , FOX JOHN M
Abstract: A quadrature amplitude modulation (QAM) communication system is provided in which data can be communicated in any one of a plurality of QAM modes, such as 16-QAM, 32-QAM, and 64-QAM (30). A receiver (70) detects the particular QAM mode transmitted on a trial and error basis, by attempting to decode the received data using different QAM modes until a synchronization condition is detected. The synchronization condition can require that a plurality of different synchronization tests be met. In a specific embodiment, a first synchronization test is met when a renormalization rate of a trellis decoder (90) is below a threshold value. A second synchronization test is met when a first synchronization word is detected in the received data. A third and final synchronization test is met when a second synchronization word is detected in the received data. In order to reduce the cost of the receiver, most of the QAM mode dependent components (76, 80, 84, 90, 98, 102) are implemented using look-up tables stored in PROMs.
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公开(公告)号：ES2100979T3
公开(公告)日：1997-07-01
申请号：ES92112305
申请日：1992-07-18
Applicant: GEN INSTRUMENT CORP
Inventor： PAIK WOO H , LERY SCOTT A , TOM ADAM S
Abstract: A method and apparatus are provided for adaptively equalizing data signals in a communications receiver. An unequalized data signal is demodulated. The demodulated data signal is filtered in an adaptive equalizer (60) that initially updates adaptive filter coefficients using error signals derived from a first algorithm. A carrier lock signal is generated (62, 78) when a phase error of a filtered signal output from the adaptive equalizer reaches a threshold value. The adaptive filter coefficients are updated (74) using error signals derived from a second algorithm instead of the first algorithm in response to the carrier lock signal (72). The first algorithm is a self-recovering equalization algorithm such as the Constant Modulus Algorithm. The second algorithm can be a decision directed algorithm. Carrier phase is recovered without the use of a phase rotator or phase de-rotator, by locating the adaptive equalizer inside of the carrier recovery loop (56). The invention is particularly adapted for use in the recovery of multilevel amplitude modulated data, such as QAM data.
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公开(公告)号：DE69219412D1
公开(公告)日：1997-06-05
申请号：DE69219412
申请日：1992-07-18
Applicant: GEN INSTRUMENT CORP
Inventor： PAIK WOO H , LERY SCOTT A , TOM ADAM S
Abstract: A method and apparatus are provided for adaptively equalizing data signals in a communications receiver. An unequalized data signal is demodulated. The demodulated data signal is filtered in an adaptive equalizer (60) that initially updates adaptive filter coefficients using error signals derived from a first algorithm. A carrier lock signal is generated (62, 78) when a phase error of a filtered signal output from the adaptive equalizer reaches a threshold value. The adaptive filter coefficients are updated (74) using error signals derived from a second algorithm instead of the first algorithm in response to the carrier lock signal (72). The first algorithm is a self-recovering equalization algorithm such as the Constant Modulus Algorithm. The second algorithm can be a decision directed algorithm. Carrier phase is recovered without the use of a phase rotator or phase de-rotator, by locating the adaptive equalizer inside of the carrier recovery loop (56). The invention is particularly adapted for use in the recovery of multilevel amplitude modulated data, such as QAM data.
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公开(公告)号：IE73443B1
公开(公告)日：1997-06-04
申请号：IE922326
申请日：1992-07-17
Applicant: GEN INSTRUMENT CORP
Inventor： PAIK WOO H , LERY SCOTT A , TOM ADAM S
Abstract: A method and apparatus are provided for adaptively equalizing data signals in a communications receiver. An unequalized data signal is demodulated. The demodulated data signal is filtered in an adaptive equalizer (60) that initially updates adaptive filter coefficients using error signals derived from a first algorithm. A carrier lock signal is generated (62, 78) when a phase error of a filtered signal output from the adaptive equalizer reaches a threshold value. The adaptive filter coefficients are updated (74) using error signals derived from a second algorithm instead of the first algorithm in response to the carrier lock signal (72). The first algorithm is a self-recovering equalization algorithm such as the Constant Modulus Algorithm. The second algorithm can be a decision directed algorithm. Carrier phase is recovered without the use of a phase rotator or phase de-rotator, by locating the adaptive equalizer inside of the carrier recovery loop (56). The invention is particularly adapted for use in the recovery of multilevel amplitude modulated data, such as QAM data.
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