| 1. |
- Anderson, John B, et al.
(författare)
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On the BCJR algorithm for rate-distortion source coding
- 2007
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448. ; 53:9, s. 3201-3207
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Tidskriftsartikel (refereegranskat)abstract
- The BCJR algorithm is an important channel decoding method. We extend it to trellis rate-distortion data compression. Beginning from source coding principles, the derivation of the algorithm avoids channel coding or soft output ideas. The encoder does not use entropy coding; equiprobable reproducer letters are emphasized since these maximize entropy. The BCJR method is demonstrated by tests of a tailbiting variant. It performs much better than the ordinary Viterbi algorithm for short and medium blocks. However, the improvement stems from tailbiting; the role of the BCJR is to achieve tailbiting in a relatively simple way. Some issues that arise with tailbiting are explored. It is shown that there is an optimal trellis state size for each block length.
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| 2. |
- Anderson, John B
(författare)
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On the complexity of bounded distance decoding for the AWGN channel
- 2002
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Ingår i: IEEE Transactions on Information Theory. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9448. ; 48:5, s. 1046-1060
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Tidskriftsartikel (refereegranskat)abstract
- Earlier work has derived the storage complexity of the bounded distance decoder (BDD) for binary-channel convolutional codes. We extend this work to the Gaussian noise channel and to partial-response codes. We show that the storage requirement similar to(2(1-R) - 1)(-t) paths for rate-R convolutional codes over the binary channel becomes similar to2(2Rt) over the Gaussian channel, where the decoder must correct t errors. Thus, convolutional coding over the Gaussian channel is not only 3 dB more energy efficient, but its decoding is simpler as well. Next, we estimate the path storage for partial-response codes, i.e., real-number convolutional codes, over the Gaussian channel. The growth rate depends primarily on the bandwidth of the code. A new optimization procedure is devised to measure the maximum storage requirement in Gaussian noise for these two code types. An analysis based on difference equations predicts the asymptotic storage growth for partial response codes.
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| 3. |
- Osthoff, Harro, et al.
(författare)
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Systematic feed-forward convolutional encoders are better than other encoders with an M-algorithm decoder
- 1998
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Ingår i: IEEE Transactions on Information Theory. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9448. ; 44, s. 831-838
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Tidskriftsartikel (refereegranskat)abstract
- Consider nonbacktracking convolutional decoders that keep a fixed number of trellis survivors. It is shown that the error performance of these depends on the early part of the distance profile and on the number of survivors kept, and not on the free distance or the details of the code generators. Particularly, the encoder may be feedforward systematic without loss. Furthermore, this kind of encoder solves the correct path loss problem in reduced-search decoders. Other kinds do not. Therefore, with almost any other decoding method than the Viterbi algorithm, systematic feed-forward encoders should be used. The conclusions in this correspondence run counter to much accepted wisdom about convolutional codes
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| 4. |
- Rusek, Fredrik, et al.
(författare)
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Constrained capacities for faster-than-Nyquist signaling
- 2009
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448. ; 55:2, s. 764-775
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with capacity computations of faster-than-Nyquist (FTN) signaling. It shows that the capacity of FTN is higher than the orthogonal pulse linear modulation capacity for all pulse shapes except the sinc. FTN signals can in fact achieve the ultimate capacity for the signal power spectral density (PSD). The paper lower and upper bounds the FTN capacity under the constraint of finite input alphabet. It is often higher than the capacity for comparable orthogonal pulse systems; sometimes it is superior to all forms of orthogonal signaling with the same PSD.
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| 5. |
- Rusek, Fredrik, et al.
(författare)
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Minimum Distance Analysis of a Certain Class of 2-D ISI Channels
- 2012
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448. ; 58:2, s. 878-887
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Tidskriftsartikel (refereegranskat)abstract
- We perform a minimum distance analysis of a class of two-dimensional intersymbol interference (ISI) channels applicable to multitrack magnetic recording and orthogonal frequency division multiplex transmission systems. Exact minimum distance for a wide class of ISI responses is derived. The fundamental analytical technique is to transform the channel into an equivalent minimum phase channel. The results improve upon the prior work of Soljanin and Georghiades.
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| 6. |
- Ståhl, Per, et al.
(författare)
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A note on tailbiting codes and their feedback encoders
- 2002
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Ingår i: IEEE Transactions on Information Theory. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9448. ; 48:2, s. 529-534
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Tidskriftsartikel (refereegranskat)abstract
- Tailbiting codes encoded by feedback convolutional encoders are studied. A condition for when tailbiting will work is given and it Is described how the encoder starting state can be obtained for feedback encoders in both controller and observer canonical forms. Finally, results from a search for systematic feedback encoders that encode tailbiting codes with good decoding bit error probabilities are presented.
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| 7. |
- Ståhl, Per, et al.
(författare)
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Optimal and near-optimal encoders for short and moderate-length tailbiting trellises
- 1999
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Ingår i: IEEE Transactions on Information Theory. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9448. ; 45:7, s. 2562-2571
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Tidskriftsartikel (refereegranskat)abstract
- The results of an extensive search for short and moderate length polynomial convolutional encoders for time-invariant tail-biting representations of block codes at rates R=1/4, 1/3, 1/2, and 2/3 are reported. The tail-biting representations found are typically as good as the best known block codes
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