Pub Date : 2001-06-24DOI: 10.1109/ISIT.2001.936103
H. Coward, R. Knopp, S. Servetto
Multiple description (MD) codes have been proposed to provide robustness against data loss in packet-switched networks. We report results on the performance of MD codes when used on bit error channels with error correcting codes, in order to handle loss of blocks when the number of errors in a black exceeds the correcting ability of the code. We find that MD codes appear to be outperformed by a more traditional system in which source and channel code parameters are jointly optimized to minimize end-to-end distortion.
{"title":"On the performance of multiple description codes over bit error channels","authors":"H. Coward, R. Knopp, S. Servetto","doi":"10.1109/ISIT.2001.936103","DOIUrl":"https://doi.org/10.1109/ISIT.2001.936103","url":null,"abstract":"Multiple description (MD) codes have been proposed to provide robustness against data loss in packet-switched networks. We report results on the performance of MD codes when used on bit error channels with error correcting codes, in order to handle loss of blocks when the number of errors in a black exceeds the correcting ability of the code. We find that MD codes appear to be outperformed by a more traditional system in which source and channel code parameters are jointly optimized to minimize end-to-end distortion.","PeriodicalId":433761,"journal":{"name":"Proceedings. 2001 IEEE International Symposium on Information Theory (IEEE Cat. No.01CH37252)","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131350609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-06-24DOI: 10.1109/ISIT.2001.936158
J. Freudenberger, Martin Bossert, V. Zybablov, S. Shavgulidze
We present a new code construction called partially concatenated convolutional codes. Parallel concatenated convolutional codes (turbo codes) and serially concatenated convolutional codes can be regarded as special cases of this construction. However, proper partitioning of the outer code sequences provides a new degree of freedom for code design.
{"title":"Partially concatenated convolutional codes","authors":"J. Freudenberger, Martin Bossert, V. Zybablov, S. Shavgulidze","doi":"10.1109/ISIT.2001.936158","DOIUrl":"https://doi.org/10.1109/ISIT.2001.936158","url":null,"abstract":"We present a new code construction called partially concatenated convolutional codes. Parallel concatenated convolutional codes (turbo codes) and serially concatenated convolutional codes can be regarded as special cases of this construction. However, proper partitioning of the outer code sequences provides a new degree of freedom for code design.","PeriodicalId":433761,"journal":{"name":"Proceedings. 2001 IEEE International Symposium on Information Theory (IEEE Cat. No.01CH37252)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121750144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-06-24DOI: 10.1109/ISIT.2001.936208
A. Kavcic, B. Marcus, M. Mitzenmacher, B. Wilson
We develop density evolution methods for evaluating the performance of Gallager's low-density parity-check (LDPC) codes over binary intersymbol interference (ISI) channels. In contrast to previous work on memoryless channels, the noise tolerance thresholds for ISI channels depend on the transmitted sequences. The concentration statements are appropriately adjusted to reflect this difference. We compare the thresholds of regular Gallager codes over the 1-D partial response channel to the i.i.d. information rate, showing that at high code rates, regular Gallager codes are asymptotically optimal.
{"title":"Deriving performance bounds for ISI channels using Gallager codes","authors":"A. Kavcic, B. Marcus, M. Mitzenmacher, B. Wilson","doi":"10.1109/ISIT.2001.936208","DOIUrl":"https://doi.org/10.1109/ISIT.2001.936208","url":null,"abstract":"We develop density evolution methods for evaluating the performance of Gallager's low-density parity-check (LDPC) codes over binary intersymbol interference (ISI) channels. In contrast to previous work on memoryless channels, the noise tolerance thresholds for ISI channels depend on the transmitted sequences. The concentration statements are appropriately adjusted to reflect this difference. We compare the thresholds of regular Gallager codes over the 1-D partial response channel to the i.i.d. information rate, showing that at high code rates, regular Gallager codes are asymptotically optimal.","PeriodicalId":433761,"journal":{"name":"Proceedings. 2001 IEEE International Symposium on Information Theory (IEEE Cat. No.01CH37252)","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115153534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-06-24DOI: 10.1109/ISIT.2001.935957
M. Goresky, A. Klapper
A feedback-with-carry shift register (FCSR) with "Fibonacci" architecture is a shift register provided with a small amount of memory which is used in the feedback algorithm. Like linear feedback shift registers (LFSRs), FCSRs provide a simple and predictable method for the fast generation of pseudorandom sequences with good statistical properties and large periods. We analyze an alternative architecture for FCSRs which is similar to the "Galois" architecture for LFSRs. We also describe the output sequences generated by d-FCSRs, a slight modification of the (Fibonacci) FCSR architecture in which the feedback bit is delayed for d clock cycles before being returned to the first cell of the shift register. We show that d-FCSRs also admit a more efficient "Galois" architecture.
{"title":"Fibonacci and Galois mode feedback with carry shift registers","authors":"M. Goresky, A. Klapper","doi":"10.1109/ISIT.2001.935957","DOIUrl":"https://doi.org/10.1109/ISIT.2001.935957","url":null,"abstract":"A feedback-with-carry shift register (FCSR) with \"Fibonacci\" architecture is a shift register provided with a small amount of memory which is used in the feedback algorithm. Like linear feedback shift registers (LFSRs), FCSRs provide a simple and predictable method for the fast generation of pseudorandom sequences with good statistical properties and large periods. We analyze an alternative architecture for FCSRs which is similar to the \"Galois\" architecture for LFSRs. We also describe the output sequences generated by d-FCSRs, a slight modification of the (Fibonacci) FCSR architecture in which the feedback bit is delayed for d clock cycles before being returned to the first cell of the shift register. We show that d-FCSRs also admit a more efficient \"Galois\" architecture.","PeriodicalId":433761,"journal":{"name":"Proceedings. 2001 IEEE International Symposium on Information Theory (IEEE Cat. No.01CH37252)","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121866374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-06-24DOI: 10.1109/ISIT.2001.936140
Howard Barnum
The author considers the tradeoff between information gained about a quantum state and disturbance caused by the measurement providing the information. For every measurement, he finds the way of making it which is least-disturbing, on average, when the initial quantum state is completely unknown.
{"title":"Information-disturbance tradeoff in quantum measurement on the uniform ensemble","authors":"Howard Barnum","doi":"10.1109/ISIT.2001.936140","DOIUrl":"https://doi.org/10.1109/ISIT.2001.936140","url":null,"abstract":"The author considers the tradeoff between information gained about a quantum state and disturbance caused by the measurement providing the information. For every measurement, he finds the way of making it which is least-disturbing, on average, when the initial quantum state is completely unknown.","PeriodicalId":433761,"journal":{"name":"Proceedings. 2001 IEEE International Symposium on Information Theory (IEEE Cat. No.01CH37252)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127691594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-06-24DOI: 10.1109/ISIT.2001.936180
J. Boutros, G. Caire
The synchronous chip-rate discrete-time CDMA channel with channel coding is analysed and the corresponding factor graph is presented. Iterative joint decoding can be derived in a simple and direct way by applying the sum-product algorithm to the factor graph. Since variables have degree 2, no computation takes place at the variable nodes. Computation at the code nodes is just soft-in soft-out (SISO) decoding, whose output is the extrinsic PMF of the coded symbols. Computation at the channel transition nodes is equivalent to MAP symbol-by-symbol multiuser detection, whose complexity is generally exponential in K. We show that several previously proposed low-complexity algorithms based on interference cancellation (IC) can be derived in a simple direct way by approximating the extrinsic PMF output by the SISO decoders either as a single mass-point PMF (hard decision) or as a Gaussian PDF with the same mean and variance (moment matching). Differently from all previously presented methods (derived from heuristic reasoning), we see clearly that extrinsic rather than a posteriori PMF should be fed back. This yields important advantages in terms of limiting achievable throughput.
{"title":"Iterative multiuser joint decoding: unified framework and asymptotic analysis","authors":"J. Boutros, G. Caire","doi":"10.1109/ISIT.2001.936180","DOIUrl":"https://doi.org/10.1109/ISIT.2001.936180","url":null,"abstract":"The synchronous chip-rate discrete-time CDMA channel with channel coding is analysed and the corresponding factor graph is presented. Iterative joint decoding can be derived in a simple and direct way by applying the sum-product algorithm to the factor graph. Since variables have degree 2, no computation takes place at the variable nodes. Computation at the code nodes is just soft-in soft-out (SISO) decoding, whose output is the extrinsic PMF of the coded symbols. Computation at the channel transition nodes is equivalent to MAP symbol-by-symbol multiuser detection, whose complexity is generally exponential in K. We show that several previously proposed low-complexity algorithms based on interference cancellation (IC) can be derived in a simple direct way by approximating the extrinsic PMF output by the SISO decoders either as a single mass-point PMF (hard decision) or as a Gaussian PDF with the same mean and variance (moment matching). Differently from all previously presented methods (derived from heuristic reasoning), we see clearly that extrinsic rather than a posteriori PMF should be fed back. This yields important advantages in terms of limiting achievable throughput.","PeriodicalId":433761,"journal":{"name":"Proceedings. 2001 IEEE International Symposium on Information Theory (IEEE Cat. No.01CH37252)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132719095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-06-24DOI: 10.1109/ISIT.2001.935951
Peter Németh, L. Rasmussen, T. Aulin
Maximum-likelihood soft-decision decoding of block coded CDMA using the A* algorithm is considered. Different heuristic functions are considered, applied to coded and uncoded CDMA. The average complexity involved in ML detection for both uncoded and coded CDMA is investigated. The (23,12) Golay code is used in the coded case.
{"title":"Maximum-likelihood detection of block coded CDMA using the A* algorithm","authors":"Peter Németh, L. Rasmussen, T. Aulin","doi":"10.1109/ISIT.2001.935951","DOIUrl":"https://doi.org/10.1109/ISIT.2001.935951","url":null,"abstract":"Maximum-likelihood soft-decision decoding of block coded CDMA using the A* algorithm is considered. Different heuristic functions are considered, applied to coded and uncoded CDMA. The average complexity involved in ML detection for both uncoded and coded CDMA is investigated. The (23,12) Golay code is used in the coded case.","PeriodicalId":433761,"journal":{"name":"Proceedings. 2001 IEEE International Symposium on Information Theory (IEEE Cat. No.01CH37252)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133311028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-06-24DOI: 10.1109/ISIT.2001.935996
M.V. Burnashev
A new upper bound for the reliability function of the Gaussian channel is presented.
给出了高斯信道可靠度函数的一个新的上界。
{"title":"On relation between code geometry and decoding error probability","authors":"M.V. Burnashev","doi":"10.1109/ISIT.2001.935996","DOIUrl":"https://doi.org/10.1109/ISIT.2001.935996","url":null,"abstract":"A new upper bound for the reliability function of the Gaussian channel is presented.","PeriodicalId":433761,"journal":{"name":"Proceedings. 2001 IEEE International Symposium on Information Theory (IEEE Cat. No.01CH37252)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134237512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-06-24DOI: 10.1109/ISIT.2001.936192
I. Dumer, K. Shabunov
Using recursive techniques, we obtain near-optimum decoding with feasible complexity for RM codes of lengths up to 512 and their subcodes.
使用递归技术，我们获得了长度为512的RM码及其子码具有可行复杂度的近最优解码。
{"title":"Near-optimum decoding for subcodes of Reed-Muller codes","authors":"I. Dumer, K. Shabunov","doi":"10.1109/ISIT.2001.936192","DOIUrl":"https://doi.org/10.1109/ISIT.2001.936192","url":null,"abstract":"Using recursive techniques, we obtain near-optimum decoding with feasible complexity for RM codes of lengths up to 512 and their subcodes.","PeriodicalId":433761,"journal":{"name":"Proceedings. 2001 IEEE International Symposium on Information Theory (IEEE Cat. No.01CH37252)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133049254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-06-24DOI: 10.1109/ISIT.2001.935970
A. Shokrollahi
Hassibi, Hochwald, Shokrollahi and Sweldens (see tech. rep., Bell Laboratories, Lucent Technologies, 2000) classified all finite groups of unitary matrices with nonzero diversity product. It is well-known, however, that differential space-time codes with vanishing diversity product still can perform reasonably well under certain conditions. We show how to compute parameters of finite groups crucial for their use as space-time constellations, using only the character table of the group. Simulations are given for the group SL(2,17).
{"title":"Group characters and unitary space-time codes","authors":"A. Shokrollahi","doi":"10.1109/ISIT.2001.935970","DOIUrl":"https://doi.org/10.1109/ISIT.2001.935970","url":null,"abstract":"Hassibi, Hochwald, Shokrollahi and Sweldens (see tech. rep., Bell Laboratories, Lucent Technologies, 2000) classified all finite groups of unitary matrices with nonzero diversity product. It is well-known, however, that differential space-time codes with vanishing diversity product still can perform reasonably well under certain conditions. We show how to compute parameters of finite groups crucial for their use as space-time constellations, using only the character table of the group. Simulations are given for the group SL(2,17).","PeriodicalId":433761,"journal":{"name":"Proceedings. 2001 IEEE International Symposium on Information Theory (IEEE Cat. No.01CH37252)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133793850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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