Pub Date : 2006-07-09DOI: 10.1109/ISIT.2006.262114
C. Deppe, Holger Schnettler
We treat here the question, whether there exists a q-ary fix-free code for a given sequence of codeword lengths. We focus mostly on results which establish the 3/4-conjecture of Ahlswede/Balkenhol/Khachatrian for special classes of lengths sequences. We construct fix-free codes with directed deBrujin graphs. We improve and generalize work of Kukorelly/Zeger and of Yekhanin
{"title":"On q-ary fix-free codes and directed deBrujin graphs","authors":"C. Deppe, Holger Schnettler","doi":"10.1109/ISIT.2006.262114","DOIUrl":"https://doi.org/10.1109/ISIT.2006.262114","url":null,"abstract":"We treat here the question, whether there exists a q-ary fix-free code for a given sequence of codeword lengths. We focus mostly on results which establish the 3/4-conjecture of Ahlswede/Balkenhol/Khachatrian for special classes of lengths sequences. We construct fix-free codes with directed deBrujin graphs. We improve and generalize work of Kukorelly/Zeger and of Yekhanin","PeriodicalId":115298,"journal":{"name":"2006 IEEE International Symposium on Information Theory","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130697865","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 : 2006-07-09DOI: 10.1109/ISIT.2006.262004
Y. Liu
We provide a low complexity communication protocol for relay channels that can achieve a significant rate reliably even when a code word spans only finite number of fading blocks on average. Both full duplex and half duplex relay are considered. In the past, when a fixed rate code word spans a finite number of fading blocks, the capacity is zero. Therefore, a large amount of research has tried to reduce outage probability and increase throughput, such as the high signal-to-noise ratio (SNR) diversity-and-multiplexing-gain-tradeoff study of relay channels. Differently, the protocol in this paper achieves a significant information rate with asymptotically zero error probability (no outage) when the number of information bits represented by a code word increases to infinity. This performance is achieved by employing rateless codes and acknowledgements so that the destination obtains just enough mutual information to decode. This approach has the advantages that the protocol is not channel statistics dependent, has low complexity, is power efficient, has high performance, and can be easily generalized to other network communication settings
{"title":"A Low Complexity Protocol for Relay Channels Employing Rateless Codes and Acknowledgement","authors":"Y. Liu","doi":"10.1109/ISIT.2006.262004","DOIUrl":"https://doi.org/10.1109/ISIT.2006.262004","url":null,"abstract":"We provide a low complexity communication protocol for relay channels that can achieve a significant rate reliably even when a code word spans only finite number of fading blocks on average. Both full duplex and half duplex relay are considered. In the past, when a fixed rate code word spans a finite number of fading blocks, the capacity is zero. Therefore, a large amount of research has tried to reduce outage probability and increase throughput, such as the high signal-to-noise ratio (SNR) diversity-and-multiplexing-gain-tradeoff study of relay channels. Differently, the protocol in this paper achieves a significant information rate with asymptotically zero error probability (no outage) when the number of information bits represented by a code word increases to infinity. This performance is achieved by employing rateless codes and acknowledgements so that the destination obtains just enough mutual information to decode. This approach has the advantages that the protocol is not channel statistics dependent, has low complexity, is power efficient, has high performance, and can be easily generalized to other network communication settings","PeriodicalId":115298,"journal":{"name":"2006 IEEE International Symposium on Information Theory","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131078182","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 : 2006-07-09DOI: 10.1109/ISIT.2006.262090
G. Shamir
We study the block entropy of patterns of sequences generated by uniform and monotonic memoryless source distributions. In the former case, the pattern entropy decreases the most from the memoryless entropy, and in the latter the least. General upper and lower bounds are presented and then applied to these distributions. Tighter bounds are derived for a uniform case. All bounds provide almost precise characterization of the pattern entropies of uniform distributions, distributions over the integers, and the geometric distribution. Of specific interest are distributions over the integers that have infinite entropy rates in the memoryless case but bounded pattern block entropies
{"title":"On Some Distributions and Their Pattern Entropies","authors":"G. Shamir","doi":"10.1109/ISIT.2006.262090","DOIUrl":"https://doi.org/10.1109/ISIT.2006.262090","url":null,"abstract":"We study the block entropy of patterns of sequences generated by uniform and monotonic memoryless source distributions. In the former case, the pattern entropy decreases the most from the memoryless entropy, and in the latter the least. General upper and lower bounds are presented and then applied to these distributions. Tighter bounds are derived for a uniform case. All bounds provide almost precise characterization of the pattern entropies of uniform distributions, distributions over the integers, and the geometric distribution. Of specific interest are distributions over the integers that have infinite entropy rates in the memoryless case but bounded pattern block entropies","PeriodicalId":115298,"journal":{"name":"2006 IEEE International Symposium on Information Theory","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131088808","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 : 2006-07-09DOI: 10.1109/ISIT.2006.261755
A. Dana, M. Sharif, B. Hassibi
In this paper we consider the effect of channel estimation error on the capacity region of MIMO Gaussian broadcast channels. It is assumed that the receivers and the transmitter have (the same) estimates of the channel coefficients (i.e., the feedback channel is noiseless). We obtain an achievable rate region based on the dirty paper coding scheme. We show that this region is given by the capacity region of a dual multi-access channel with a noise covariance that depends on the transmit power. We explore this duality to give the asymptotic behavior of the sum-rate for a system with a large number of user, i.e., n rarr infin. It is shown that as long as the estimation error is of fixed (w.r.t n) variance, the sum-capacity is of order M log log n, where M is the number of antennas deployed at the transmitter. We further obtain the sum-rate loss due to the estimation error. Finally, we consider a training-based scheme for block fading MISO Gaussian broadcast channels. We find the optimum length of the training interval as well as the optimum power used for training in order to maximize the achievable sum-rate
{"title":"On the Capacity Region of Multi-Antenna Gaussian Broadcast Channels with Estimation Error","authors":"A. Dana, M. Sharif, B. Hassibi","doi":"10.1109/ISIT.2006.261755","DOIUrl":"https://doi.org/10.1109/ISIT.2006.261755","url":null,"abstract":"In this paper we consider the effect of channel estimation error on the capacity region of MIMO Gaussian broadcast channels. It is assumed that the receivers and the transmitter have (the same) estimates of the channel coefficients (i.e., the feedback channel is noiseless). We obtain an achievable rate region based on the dirty paper coding scheme. We show that this region is given by the capacity region of a dual multi-access channel with a noise covariance that depends on the transmit power. We explore this duality to give the asymptotic behavior of the sum-rate for a system with a large number of user, i.e., n rarr infin. It is shown that as long as the estimation error is of fixed (w.r.t n) variance, the sum-capacity is of order M log log n, where M is the number of antennas deployed at the transmitter. We further obtain the sum-rate loss due to the estimation error. Finally, we consider a training-based scheme for block fading MISO Gaussian broadcast channels. We find the optimum length of the training interval as well as the optimum power used for training in order to maximize the achievable sum-rate","PeriodicalId":115298,"journal":{"name":"2006 IEEE International Symposium on Information Theory","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133536917","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 : 2006-07-09DOI: 10.1109/ISIT.2006.261834
S. Bhadra, P. Gupta, S. Shakkottai
We consider a finite-field model for the wireless broadcast and additive interference network (WBAIN), both in the presence and absence of fading. We show that the single-source unicast capacity (with extension to multicast) of a WBAIN with or without fading can be upper bounded by the capacity of an equivalent broadcast erasure network. We further present a coding strategy for WBAINs with i.i.d. and uniform fading based on random linear coding at each node that achieves a rate differing from the upper bound by no more than O(1/q), where q is the field size. Using these results, we show that channel fading in conjunction with network coding can lead to large gains in the unicast (multicast) capacity as compared to no fading
{"title":"On Network Coding for Interference Networks","authors":"S. Bhadra, P. Gupta, S. Shakkottai","doi":"10.1109/ISIT.2006.261834","DOIUrl":"https://doi.org/10.1109/ISIT.2006.261834","url":null,"abstract":"We consider a finite-field model for the wireless broadcast and additive interference network (WBAIN), both in the presence and absence of fading. We show that the single-source unicast capacity (with extension to multicast) of a WBAIN with or without fading can be upper bounded by the capacity of an equivalent broadcast erasure network. We further present a coding strategy for WBAINs with i.i.d. and uniform fading based on random linear coding at each node that achieves a rate differing from the upper bound by no more than O(1/q), where q is the field size. Using these results, we show that channel fading in conjunction with network coding can lead to large gains in the unicast (multicast) capacity as compared to no fading","PeriodicalId":115298,"journal":{"name":"2006 IEEE International Symposium on Information Theory","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133579590","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 : 2006-07-09DOI: 10.1109/ISIT.2006.261991
M. Bloch, A. Thangaraj, S. McLaughlin, J. Merolla
This paper investigates a practical secret key agreement protocol over the Gaussian wire-tap channel. The protocol is based on an efficient information reconciliation method which allows two parties having access to correlated continuous random variables to agree on a common bit string. We describe an explicit reconciliation method based on LDPC codes optimized with EXIT charts and density evolution. When used in conjunction with existing privacy amplification techniques our method allows secret key agreement over the Gaussian wire-tap channel close to the secrecy capacity
{"title":"LDPC-based secret key agreement over the Gaussian wiretap channel","authors":"M. Bloch, A. Thangaraj, S. McLaughlin, J. Merolla","doi":"10.1109/ISIT.2006.261991","DOIUrl":"https://doi.org/10.1109/ISIT.2006.261991","url":null,"abstract":"This paper investigates a practical secret key agreement protocol over the Gaussian wire-tap channel. The protocol is based on an efficient information reconciliation method which allows two parties having access to correlated continuous random variables to agree on a common bit string. We describe an explicit reconciliation method based on LDPC codes optimized with EXIT charts and density evolution. When used in conjunction with existing privacy amplification techniques our method allows secret key agreement over the Gaussian wire-tap channel close to the secrecy capacity","PeriodicalId":115298,"journal":{"name":"2006 IEEE International Symposium on Information Theory","volume":"154 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133616194","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 : 2006-07-09DOI: 10.1109/ISIT.2006.261609
H. Behroozi, M. Soleymani
We evaluate the performance of the successive coding strategy for the problem of multiterminal lossy coding of correlated Gaussian sources. We consider the m-helper problem for the special case of m = 1 where one source provides partial side information to the decoder to help reconstruction of the main source signal. Our results reconfirm the fact that the successive coding strategy is an optimal strategy in sense of achieving the rate-distortion function of the 1-helper problem. Comparing the performance of the sequential coding with the performance of the successive coding, we show that there is no sum rate loss when the side information is not available at the encoder. Finally, based on the successive coding strategy, we provide an achievable rate-distortion region for the m-helper problem
{"title":"Successive Coding Strategy in the m-helper Problem","authors":"H. Behroozi, M. Soleymani","doi":"10.1109/ISIT.2006.261609","DOIUrl":"https://doi.org/10.1109/ISIT.2006.261609","url":null,"abstract":"We evaluate the performance of the successive coding strategy for the problem of multiterminal lossy coding of correlated Gaussian sources. We consider the m-helper problem for the special case of m = 1 where one source provides partial side information to the decoder to help reconstruction of the main source signal. Our results reconfirm the fact that the successive coding strategy is an optimal strategy in sense of achieving the rate-distortion function of the 1-helper problem. Comparing the performance of the sequential coding with the performance of the successive coding, we show that there is no sum rate loss when the side information is not available at the encoder. Finally, based on the successive coding strategy, we provide an achievable rate-distortion region for the m-helper problem","PeriodicalId":115298,"journal":{"name":"2006 IEEE International Symposium on Information Theory","volume":"352 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133105195","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 : 2006-07-09DOI: 10.1109/ISIT.2006.261638
B. Rankov, A. Wittneben
We study the two-way communication problem for the relay channel. Hereby, two terminals communicate simultaneously in both directions with the help of one relay. We consider the restricted two-way problem, i.e., the encoders at both terminals do not cooperate. We provide achievable rate regions for different cooperation strategies, such as decode-and-forward based on block Markov superposition coding. We also evaluate the regions for the special case of additive white Gaussian noise channels. We show that a combined strategy of block Markov superposition coding and Wyner-Ziv coding achieves the cut-set upper bound on the sum-rate of the two-way relay channel when the relay is in the proximity of one of the terminals
{"title":"Achievable Rate Regions for the Two-way Relay Channel","authors":"B. Rankov, A. Wittneben","doi":"10.1109/ISIT.2006.261638","DOIUrl":"https://doi.org/10.1109/ISIT.2006.261638","url":null,"abstract":"We study the two-way communication problem for the relay channel. Hereby, two terminals communicate simultaneously in both directions with the help of one relay. We consider the restricted two-way problem, i.e., the encoders at both terminals do not cooperate. We provide achievable rate regions for different cooperation strategies, such as decode-and-forward based on block Markov superposition coding. We also evaluate the regions for the special case of additive white Gaussian noise channels. We show that a combined strategy of block Markov superposition coding and Wyner-Ziv coding achieves the cut-set upper bound on the sum-rate of the two-way relay channel when the relay is in the proximity of one of the terminals","PeriodicalId":115298,"journal":{"name":"2006 IEEE International Symposium on Information Theory","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128849923","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 : 2006-07-09DOI: 10.1109/ISIT.2006.261594
S. Jaggi, Yuval Cassuto, M. Effros
In this paper we consider the per-node run-time complexity of network multicast codes. We show that the randomized algebraic network code design algorithms described extensively in the literature result in codes that on average require a number of operations that scales quadratically with the block-length m of the codes. We then propose an alternative type of linear network code whose complexity scales linearly in m and still enjoys the attractive properties of random algebraic network codes. We also show that these codes are optimal in the sense that any rate-optimal linear network code must have at least a linear scaling in run-time complexity
{"title":"Low Complexity Encoding for Network Codes","authors":"S. Jaggi, Yuval Cassuto, M. Effros","doi":"10.1109/ISIT.2006.261594","DOIUrl":"https://doi.org/10.1109/ISIT.2006.261594","url":null,"abstract":"In this paper we consider the per-node run-time complexity of network multicast codes. We show that the randomized algebraic network code design algorithms described extensively in the literature result in codes that on average require a number of operations that scales quadratically with the block-length m of the codes. We then propose an alternative type of linear network code whose complexity scales linearly in m and still enjoys the attractive properties of random algebraic network codes. We also show that these codes are optimal in the sense that any rate-optimal linear network code must have at least a linear scaling in run-time complexity","PeriodicalId":115298,"journal":{"name":"2006 IEEE International Symposium on Information Theory","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134491678","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 : 2006-07-09DOI: 10.1109/ISIT.2006.261614
Siddharth K. Srinivasan, L. Lampe, V. Pauli
The random coding exponent for differential modulation with finite signal sets over block-fading channels and multiple-symbol differential detection with an observation window size of N symbols is considered. Different from and in extension to previous work, the channel coherence interval is independent of N and the case of spatial transmit diversity is included. In this context, we also devise bounds and approximations of the random coding exponent, which allow for efficient numerical evaluation. The presented numerical results provide useful information on the performance of coded differential transmission with short to moderate code lengths
{"title":"On the Random Coding Exponent for Differential Modulation and Detection","authors":"Siddharth K. Srinivasan, L. Lampe, V. Pauli","doi":"10.1109/ISIT.2006.261614","DOIUrl":"https://doi.org/10.1109/ISIT.2006.261614","url":null,"abstract":"The random coding exponent for differential modulation with finite signal sets over block-fading channels and multiple-symbol differential detection with an observation window size of N symbols is considered. Different from and in extension to previous work, the channel coherence interval is independent of N and the case of spatial transmit diversity is included. In this context, we also devise bounds and approximations of the random coding exponent, which allow for efficient numerical evaluation. The presented numerical results provide useful information on the performance of coded differential transmission with short to moderate code lengths","PeriodicalId":115298,"journal":{"name":"2006 IEEE International Symposium on Information Theory","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127246350","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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