US5848102A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for encoding/decoding QAM trellis coded data
Assignee: Qualcomm Inc
•
Filing: 1996-09-09
•
Granted: 1998-12-08
•
Expires: 2016-09-09
Abstract
Abstract A method and apparatus for encoding and decoding QAM trellis modulated data. In the transmitter, a subset of bits of an input bit set are convolutionally encoded based upon a punctured convolutional code of a lower data rate to provide a set of coded symbols. The coded symbols and the uncoded bits of the input bit set are provided to a QAM modulator to provide a QAM modulation signal indicative of the values of coded symbols and the uncoded bits. In the receiver a QAM demodulator converts the received QAM signal to QAM signal space coordinates. A decoder employing the Viterbi algorithm is used to reconstruct a corrected estimate of the values of the coded data bits from the received signal coordinates. The corrected estimate of the values of the coded data bits are then used in conjunction with the received signal coordinates to provide corrected estimates of the values of the uncoded input bits.
Inventors
- 👤 Ephraim Zehavi
- 👤 Jack Keil Wolf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:51
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/32; H04L27/34; H04L27/3405; H04L27/3416; H04L27/3427; H04L27/3438; H03; H03M; H03M13/00; H03M13/25; H03M13/256; H03M13/37; H03M13/39; H03M13/3961; H03M13/41; H04L1/00; H04L1/004; H04L1/0045; H04L1/0054; H04L1/0056; H04L1/0059; H04L1/006; H04L1/0067; H04L1/0068
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
180 words
An apparatus for decoding Quadrature Amplitude Modulation (QAM) trellis coded data comprising: decoder means for receiving information relating to signal space coordinates of a received signal and decoding said signal space information according to a predetermined trellis decoding format based upon a punctured convolutional encoding format to provide an estimate of a subset of bits represented by said received signal; sector means for receiving said signal information and for providing a sector number in accordance with said signal information and a predefined mapping function, said sector number corresponding to said signal space information indicative of a predefined area in the signal space plane in the proximity of said signal space coordinates; encoder means for receiving said estimated subset of bits and encoding said subset of bits according to a punctured convolutional encoding format based upon a lower rate convolutional encoding format to provide a plurality of encoded symbols; and decision means for receiving said sector number and said encoded symbols and providing an estimate of remaining uncoded bits represented by said received signal in accordance with a predetermined decision format.
Claim 2
Independent Claim
180 words
An apparatus for decoding Quadrature Amplitude Modulation (QAM) trellis coded data comprising: decoder means for receiving information relating to signal space coordinates of a received signal and decoding said signal space information according to a predetermined trellis decoding format based upon a punctured convolutional encoding format to provide an estimate of a subset of bits represented by said received signal; sector means for receiving said signal information and for providing a sector number in accordance with said signal information and a predefined mapping function, said sector number corresponding to said signal space information indicative of a predefined area in the signal space plane in the proximity of said signal space coordinates; encoder means for receiving said estimated subset of bits and encoding said subset of bits according to a punctured convolutional encoding format based upon a lower rate convolutional encoding format to provide a plurality of encoded symbols; and decision means for receiving said sector number and said encoded symbols and providing an estimate of remaining uncoded bits represented by said received signal in accordance with a predetermined decision format.
Claim 3
Dependent Claim
20 words
The apparatus of claim 1 further comprising a demodulation means for converting said received signal to said signal space coordinates.
Claim 4
Dependent Claim
64 words
The apparatus of claim 1 wherein said decoder means comprises: branch metric means for receiving said signal space information and providing branch metric data indicative of the probabilities of alternative hypotheses of the values of said subset of bits; and Viterbi decoding means for receiving branch metric data and providing an estimate of said subset of bits in accordance with a trellis decoding format.
Claim 5
Dependent Claim
14 words
The apparatus of claim 3 further comprising means for storing said branch metric data.
Claim 6
Dependent Claim
14 words
The apparatus of claim 4 further comprising means for compressing said branch metric data.
Claim 7
Dependent Claim
29 words
The apparatus of claim 5 wherein in said means for compressing branch metric data comprises quantizing said branch metric data to an integer value of less than five bits.
Claim 8
Dependent Claim
23 words
The apparatus of claim 1 wherein said encoding means comprises a rate 3/4 convolutional encoder based upon a punctured rate 1/2 convolutional code.
Claim 9
Dependent Claim
31 words
The apparatus of claim 1 further comprising delay means for receiving and delaying for a predetermined duration said estimate of said subset of bits to provide a delayed subset of bits.
Claim 10
Dependent Claim
25 words
The apparatus of claim 7 wherein said rate 3/4 convolutional encoder comprises a rate 3/4 convolutional encoder based upon a punctured rate 1/2 convolutional code.
Claim 11
Dependent Claim
13 words
The apparatus of claim 2 wherein said demodulation means comprises a 128-QAM demodulator.
Claim 12
Dependent Claim
13 words
The apparatus of claim 1 further comprising means for storing said sector number.
References Cited (Backward Citations)
US4562425A
Cited
US4755988A
Cited
US4805174A
Cited
US4939555A
Cited
US5233629A
Cited
US5363408A
Cited
US5418798A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-12-07 | 2002-06-08 | 2002-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-07 | 2006-06-08 | 2006-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-07 | 2010-06-08 | 2010-12-08 | $7700.00 | Window Closed / Lapsed |