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| 2. |
- Handlery, Marc, et al.
(författare)
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A distance approach to window decoding
- 2002
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Ingår i: Problems of Information Transmission. - 0032-9460. ; 38:3, s. 169-181
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Tidskriftsartikel (refereegranskat)abstract
- In convolutional coding, code sequences have infinite length; thus, a maximum-likelihood decoder implies an infinite delay. Due to memory and delay constraints in practical coding schemes, convolutional codes often are either terminated or decoded by a window decoder. When a window decoder is used, the convolutional code sequence is not terminated; instead, the window decoder estimates information digits after receiving a finite number of noise-corrupted code symbols, thereby keeping the decoding delay short. An exact characterization of the error-correcting capability of window decoded convolutional codes is given by using active distances of convolutional codes.
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| 3. |
- Handlery, Marc, et al.
(författare)
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Encoder and distance properties of woven convolutional codes with one tailbiting component code
- 2002
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Ingår i: Problems of Information Transmission. - 0032-9460. ; 38:1, s. 41-49
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Tidskriftsartikel (refereegranskat)abstract
- Woven convolutional codes with one tailbiting component code are studied and their generator matrices are given. It is shown that, if the constituent encoders are identical, a woven convolutional encoder with an outer convolutional warp and one inner tailbiting encoder (WIT) generates the same code as a woven convolutional encoder with one outer tailbiting encoder and an inner convolutional warp (WOT). However, for rate R tb < 1 tailbiting encoders, the WOT cannot be an encoder realization with a minimum number of delay elements. Lower bounds on the free distance and active distances of woven convolutional codes with a tailbiting component code are given. These bounds are equal to those for woven codes consisting exclusively of unterminated convolutional codes. However, for woven convolutional codes with one tailbiting component code, the conditions for the bounds to hold are less strict.
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| 4. |
- Handlery, Marc, et al.
(författare)
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Some distance properties of tailbiting codes
- 2001
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Ingår i: [Host publication title missing]. - 0780371232 ; , s. 290-290
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Konferensbidrag (refereegranskat)abstract
- The active tailbiting segment distance for convolutional codes is introduced. Together with the earlier defined active burst distance, it describes the error correcting capability of a tailbiting code encoded by a convolutional encoder. Lower bounds on the new active distance as well as an upper bound on the ratio between tailbiting length and memory of the encoder such that its minimum
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| 5. |
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| 6. |
- Höst, Stefan, et al.
(författare)
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A distance measure tailored to tailbiting codes
- 2002
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Ingår i: Problems of Information Transmission. - 0032-9460. ; 38:4, s. 280-295
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Tidskriftsartikel (refereegranskat)abstract
- The error-correcting capability of tailbiting codes generated by convolutional encoders is described. In order to obtain a description beyond what the minimum distance d min of the tailbiting code implies, the active tailbiting segment distance is introduced. The description of correctable error patterns via active distances leads to an upper bound on the decoding block error probability of tailbiting codes. The necessary length of a tailbiting code so that its minimum distance is equal to the free distance d free of the convolutional code encoded by the same encoder is easily obtained from the active tailbiting segment distance. This is useful when designing and analyzing concatenated convolutional codes with component codes that are terminated using the tailbiting method. Lower bounds on the active tailbiting segment distance and an upper bound on the ratio between the tailbiting length and memory of the convolutional generator matrix such that d min equals d free are derived. Furthermore, affine lower bounds on the active tailbiting segment distance suggest that good tailbiting codes are generated by convolutional encoders with large active-distance slopes.
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| 7. |
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| 8. |
- Höst, Stefan, et al.
(författare)
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Active distances and cascaded convolutional codes
- 1997
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Ingår i: [Host publication title missing]. - 0780339568 ; , s. 107-107
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Konferensbidrag (refereegranskat)abstract
- A family of active distances for convolutional codes is introduced. Lower bounds are derived for the ensemble of periodically time-varying convolutional codes.
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| 9. |
- Höst, Stefan, et al.
(författare)
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Active distances for convolutional codes
- 1999
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Ingår i: IEEE Transactions on Information Theory. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9448. ; 45:2, s. 658-669
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Tidskriftsartikel (refereegranskat)abstract
- A family of active distance measures for general convolutional codes is defined. These distances are generalizations of the extended distances introduced by Thommesen and Justesen (1983) for unit memory convolutional codes. It is shown that the error correcting capability of a convolutional code is determined by the active distances. The ensemble of periodically time-varying convolutional codes is defined and lower bounds on the active distances are derived for this ensemble. The active distances are very useful in the analysis of concatenated convolutional encoders
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| 10. |
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