Pub Date : 2015-05-06DOI: 10.1109/IWCIT.2015.7140208
M. N. Khormuji, M. Emadi
We investigate the general relay channel with state that is noncausally known at the source. We first present a multiletter characterization of the capacity using the Gelfand-Pinsker encoding scheme. We then tailor the result to the general Gaussian relay channel with additive interference noncausally known at the source and compute a closed-form lower bound to the capacity using the joint dirty paper coding (DPC) and multidimensional linear relaying. We finally demonstrate that a potentially suboptimal evaluation of the proposed lower bound can simultaneously outperform known state-of-art coding strategies including DPC with signal description or state description along with compress-and-forward, noisy network coding and decode-and-forward.
{"title":"On the capacity of the relay channel with known state at the source","authors":"M. N. Khormuji, M. Emadi","doi":"10.1109/IWCIT.2015.7140208","DOIUrl":"https://doi.org/10.1109/IWCIT.2015.7140208","url":null,"abstract":"We investigate the general relay channel with state that is noncausally known at the source. We first present a multiletter characterization of the capacity using the Gelfand-Pinsker encoding scheme. We then tailor the result to the general Gaussian relay channel with additive interference noncausally known at the source and compute a closed-form lower bound to the capacity using the joint dirty paper coding (DPC) and multidimensional linear relaying. We finally demonstrate that a potentially suboptimal evaluation of the proposed lower bound can simultaneously outperform known state-of-art coding strategies including DPC with signal description or state description along with compress-and-forward, noisy network coding and decode-and-forward.","PeriodicalId":166939,"journal":{"name":"2015 Iran Workshop on Communication and Information Theory (IWCIT)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128310337","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 : 2015-05-06DOI: 10.1109/IWCIT.2015.7140209
Salman Beigi, A. Gohari
In this paper, we consider the problem of simulating one copy of a zero-capacity two-way channel from arbitrary many copies of another two-way channel. The motivation for this problem comes from foundation of quantum physics where zero-capacity two-way channels (a.k.a. no-signaling boxes) serve as the abstract objects for studying non-locality. We provide necessary conditions for the possibility of channel simulation using two measures of correlation, namely maximal correlation and hypercontractivity ribbon. It is shown that when these measures are defined appropriately for two-way channels, they are monotonically decreasing under local operations. Our result allows us to establish a conjecture about the impossibility of simulating isotropic no-signaling boxes from each other.
{"title":"Two-way channel simulation","authors":"Salman Beigi, A. Gohari","doi":"10.1109/IWCIT.2015.7140209","DOIUrl":"https://doi.org/10.1109/IWCIT.2015.7140209","url":null,"abstract":"In this paper, we consider the problem of simulating one copy of a zero-capacity two-way channel from arbitrary many copies of another two-way channel. The motivation for this problem comes from foundation of quantum physics where zero-capacity two-way channels (a.k.a. no-signaling boxes) serve as the abstract objects for studying non-locality. We provide necessary conditions for the possibility of channel simulation using two measures of correlation, namely maximal correlation and hypercontractivity ribbon. It is shown that when these measures are defined appropriately for two-way channels, they are monotonically decreasing under local operations. Our result allows us to establish a conjecture about the impossibility of simulating isotropic no-signaling boxes from each other.","PeriodicalId":166939,"journal":{"name":"2015 Iran Workshop on Communication and Information Theory (IWCIT)","volume":"55 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128936867","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 : 2015-05-06DOI: 10.1109/IWCIT.2015.7140219
Behrooz Razeghi, N. Okati, G. Hodtani
In this paper, first we propose a new approach for mathematical multiple criteria decision making (MCDM) methods using information theoretic measures, entropy and divergence. Using the concept of entropy, we determine the impact of each criterion in decision making process. The Shannon's entropy has been previously employed for this purpose. In this paper we use Renyi's entropy and the concept of information potential of each criterion for weight assessment. Next, we introduce divergence as new separation measure for MCDM methods. The results indicate that the new measure outperforms the conventional Euclidean distance measure. These techniques employed in MCDM methods are new and may be of independent interest. Also, we introduce a new perspective for the decision making problems. We propose time as a new dimension for conventional mathematical MCDM methods. This dimension opens a new horizon for future MCDM methods which are based on given decision matrix. To the best of our knowledge, no prior work has studied the MCDM methods from this point of view. Using the criteria values for each candidate at different time instances, we estimate the probability distribution of each criterion in order to accommodation to the criteria value uncertainty. Finally, by utilizing the generalized correlation function, i.e. correntropy, we study the statistical dependencies of criteria in the same and different time instances.
{"title":"A novel approach to mathematical multiple criteria decision making methods based on information theoretic measures","authors":"Behrooz Razeghi, N. Okati, G. Hodtani","doi":"10.1109/IWCIT.2015.7140219","DOIUrl":"https://doi.org/10.1109/IWCIT.2015.7140219","url":null,"abstract":"In this paper, first we propose a new approach for mathematical multiple criteria decision making (MCDM) methods using information theoretic measures, entropy and divergence. Using the concept of entropy, we determine the impact of each criterion in decision making process. The Shannon's entropy has been previously employed for this purpose. In this paper we use Renyi's entropy and the concept of information potential of each criterion for weight assessment. Next, we introduce divergence as new separation measure for MCDM methods. The results indicate that the new measure outperforms the conventional Euclidean distance measure. These techniques employed in MCDM methods are new and may be of independent interest. Also, we introduce a new perspective for the decision making problems. We propose time as a new dimension for conventional mathematical MCDM methods. This dimension opens a new horizon for future MCDM methods which are based on given decision matrix. To the best of our knowledge, no prior work has studied the MCDM methods from this point of view. Using the criteria values for each candidate at different time instances, we estimate the probability distribution of each criterion in order to accommodation to the criteria value uncertainty. Finally, by utilizing the generalized correlation function, i.e. correntropy, we study the statistical dependencies of criteria in the same and different time instances.","PeriodicalId":166939,"journal":{"name":"2015 Iran Workshop on Communication and Information Theory (IWCIT)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114082365","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 : 2015-05-06DOI: 10.1109/IWCIT.2015.7140207
Milad Sefidgaran, A. Gohari, M. Aref
In this paper we study the sum modulo two problem proposed by Körner and Marton. In this source coding problem, two transmitters who observe binary sources X and Y, send messages of limited rate to a receiver whose goal is to compute the sum modulo of X and Y. This problem has been solved for the two special cases of independent and symmetric sources. In both of these cases, the rate pair (H(X|Y), H(Y|X)) is achievable. The best known outer bound for this problem is a conventional cut-set bound, and the best known inner bound is derived by Ahlswede and Han using a combination of Slepian-Wolf and Körner-Marton's coding schemes. In this paper, we propose a new outer bound which is strictly better than the cut-set bound. In particular, we show that the rate pair (H(X|Y), H(Y|X)) is not achievable for any binary sources other than independent and symmetric sources. Then, we study the minimum achievable sum-rate using Ahlswede-Han's region and propose a conjecture that this amount is not less than minimum of Slepian-Wolf and Körner-Marton's achievable sum-rates. We provide some evidences for this conjecture.
{"title":"On Körner-Marton's sum modulo two problem","authors":"Milad Sefidgaran, A. Gohari, M. Aref","doi":"10.1109/IWCIT.2015.7140207","DOIUrl":"https://doi.org/10.1109/IWCIT.2015.7140207","url":null,"abstract":"In this paper we study the sum modulo two problem proposed by Körner and Marton. In this source coding problem, two transmitters who observe binary sources X and Y, send messages of limited rate to a receiver whose goal is to compute the sum modulo of X and Y. This problem has been solved for the two special cases of independent and symmetric sources. In both of these cases, the rate pair (H(X|Y), H(Y|X)) is achievable. The best known outer bound for this problem is a conventional cut-set bound, and the best known inner bound is derived by Ahlswede and Han using a combination of Slepian-Wolf and Körner-Marton's coding schemes. In this paper, we propose a new outer bound which is strictly better than the cut-set bound. In particular, we show that the rate pair (H(X|Y), H(Y|X)) is not achievable for any binary sources other than independent and symmetric sources. Then, we study the minimum achievable sum-rate using Ahlswede-Han's region and propose a conjecture that this amount is not less than minimum of Slepian-Wolf and Körner-Marton's achievable sum-rates. We provide some evidences for this conjecture.","PeriodicalId":166939,"journal":{"name":"2015 Iran Workshop on Communication and Information Theory (IWCIT)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125918186","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 : 2015-05-06DOI: 10.1109/IWCIT.2015.7140221
Z. Samadi, V. Vakili, F. Haddadi
Interference alignment (IA) is a transmission strategy that attempts to exploit all degrees of freedom available at the transmitter or at the receiver in a multiuser channel. This paper proposes a new scheme named channel aided interference alignment. It makes use of the channel structure beside the linear interference alignment schemes to achieve the optimum degrees of freedom in a K user interference channel. In case the channel matrix does meet the specified structure, the proposed scheme achieves the optimum degrees of freedom at a finite signal to noise ratio and by using limited number of channel realizations; it turns to the usual linear vector interference alignment schemes otherwise. For the case of 3 user interference channel, it would be shown that if only one of interfering channel coefficients can be designed to a specific value, interference would be aligned perfectly at all the receivers.
{"title":"Perfect interference alignment utilizing channel structure","authors":"Z. Samadi, V. Vakili, F. Haddadi","doi":"10.1109/IWCIT.2015.7140221","DOIUrl":"https://doi.org/10.1109/IWCIT.2015.7140221","url":null,"abstract":"Interference alignment (IA) is a transmission strategy that attempts to exploit all degrees of freedom available at the transmitter or at the receiver in a multiuser channel. This paper proposes a new scheme named channel aided interference alignment. It makes use of the channel structure beside the linear interference alignment schemes to achieve the optimum degrees of freedom in a K user interference channel. In case the channel matrix does meet the specified structure, the proposed scheme achieves the optimum degrees of freedom at a finite signal to noise ratio and by using limited number of channel realizations; it turns to the usual linear vector interference alignment schemes otherwise. For the case of 3 user interference channel, it would be shown that if only one of interfering channel coefficients can be designed to a specific value, interference would be aligned perfectly at all the receivers.","PeriodicalId":166939,"journal":{"name":"2015 Iran Workshop on Communication and Information Theory (IWCIT)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117232822","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 : 2015-05-06DOI: 10.1109/IWCIT.2015.7140213
Hassan Khodaiemehr, D. Kiani, Mohammad-Reza Sadeghi
LDPC lattices were first family of lattices which have efficient decoding algorithm in high dimensions. An LDPC lattice can be constructed from Construction D' and a number of nested LDPC codes. When we consider one code as underlying code of these lattices, one-level LDPC lattices will be obtained. In this paper we propose a new encoding and decoding method for one-level LDPC lattices. We also establish an efficient shaping method for these lattices based on hypercube shaping. Then, based on this encoding and decoding, we propose the implementation of block Markov encoding for one-way relay networks, using obtained one-level LDPC lattice codes. Our proposed decoding algorithm has lower complexity than those given for LDLC lattices.
{"title":"One-level LDPC lattice codes for the relay channels","authors":"Hassan Khodaiemehr, D. Kiani, Mohammad-Reza Sadeghi","doi":"10.1109/IWCIT.2015.7140213","DOIUrl":"https://doi.org/10.1109/IWCIT.2015.7140213","url":null,"abstract":"LDPC lattices were first family of lattices which have efficient decoding algorithm in high dimensions. An LDPC lattice can be constructed from Construction D' and a number of nested LDPC codes. When we consider one code as underlying code of these lattices, one-level LDPC lattices will be obtained. In this paper we propose a new encoding and decoding method for one-level LDPC lattices. We also establish an efficient shaping method for these lattices based on hypercube shaping. Then, based on this encoding and decoding, we propose the implementation of block Markov encoding for one-way relay networks, using obtained one-level LDPC lattice codes. Our proposed decoding algorithm has lower complexity than those given for LDLC lattices.","PeriodicalId":166939,"journal":{"name":"2015 Iran Workshop on Communication and Information Theory (IWCIT)","volume":"74 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120898294","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 : 2015-05-06DOI: 10.1109/IWCIT.2015.7140204
Vahid Aref
In this paper, we study the performance of spatially coupled LT (SC-LT) codes under low-complexity belief-propagation (BP) decoding when the transmission is over a binary erasure channel (BEC). We derive a tight upper bound and lower bound on the asymptotic error probability of these rateless codes in terms of overhead and the check degree in the limit of block-length. We show that for a given overhead, the error probability of SC-LT codes is independent of erasure probability of channel and decays exponentially fast in the check degree. We show that the channel capacity can be approached by using a high-rate precoder.
{"title":"Rateless codes from spatially coupled regular-LT codes","authors":"Vahid Aref","doi":"10.1109/IWCIT.2015.7140204","DOIUrl":"https://doi.org/10.1109/IWCIT.2015.7140204","url":null,"abstract":"In this paper, we study the performance of spatially coupled LT (SC-LT) codes under low-complexity belief-propagation (BP) decoding when the transmission is over a binary erasure channel (BEC). We derive a tight upper bound and lower bound on the asymptotic error probability of these rateless codes in terms of overhead and the check degree in the limit of block-length. We show that for a given overhead, the error probability of SC-LT codes is independent of erasure probability of channel and decays exponentially fast in the check degree. We show that the channel capacity can be approached by using a high-rate precoder.","PeriodicalId":166939,"journal":{"name":"2015 Iran Workshop on Communication and Information Theory (IWCIT)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120960243","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 : 2015-05-06DOI: 10.1109/IWCIT.2015.7140214
Sadjad Imani, Reza Shahbazian, S. Ghorashi
In this paper a new decoding algorithm for low density parity check (LDPC) codes based on bit flipping (BF) is proposed. In the proposed algorithm, the BF criterion benefits the data correlation between the decoded and received signal in current and previous stages. The proposed algorithm also degrades the decoding probability of one code word to another one in the same codebook. Simulation results confirm our theoretical formulation and show a good enhancement in code error rate and bit error rate of the proposed decoding algorithm compared to the conventional ones.
{"title":"An iterative bit flipping based decoding algorithm for LDPC codes","authors":"Sadjad Imani, Reza Shahbazian, S. Ghorashi","doi":"10.1109/IWCIT.2015.7140214","DOIUrl":"https://doi.org/10.1109/IWCIT.2015.7140214","url":null,"abstract":"In this paper a new decoding algorithm for low density parity check (LDPC) codes based on bit flipping (BF) is proposed. In the proposed algorithm, the BF criterion benefits the data correlation between the decoded and received signal in current and previous stages. The proposed algorithm also degrades the decoding probability of one code word to another one in the same codebook. Simulation results confirm our theoretical formulation and show a good enhancement in code error rate and bit error rate of the proposed decoding algorithm compared to the conventional ones.","PeriodicalId":166939,"journal":{"name":"2015 Iran Workshop on Communication and Information Theory (IWCIT)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114472775","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 : 2015-05-06DOI: 10.1109/IWCIT.2015.7140215
M. R. Zefreh, J. Salehi
In this paper, an accurate model for the probability density function (pdf) of the random decision variable Y in an ultrafast digital lightwave communication system, utilizing power-cubic all-optical nonlinear preprocessor is presented. The proposed model can replace the prevalent Gaussian approximation, as the accuracy of the latter is discredited by Monte-Carlo simulation. The Log-Pearson type-3 probability density function (LP3 pdf) is shown to appropriately represents the random decision variable Y. Three characteristic parameters of the LP3 pdf are also obtained through the three moments of the decision variable Y. Finally, the system error probability is revisited using the obtained LP3 pdf of the decision variable, the result of which is in excellent consistency with rigorous Monte-Carlo simulation.
{"title":"Statistical characterization of the output of nonlinear power-cubic detection unit for ultrashort light pulse communication in the presence of Gaussian noise","authors":"M. R. Zefreh, J. Salehi","doi":"10.1109/IWCIT.2015.7140215","DOIUrl":"https://doi.org/10.1109/IWCIT.2015.7140215","url":null,"abstract":"In this paper, an accurate model for the probability density function (pdf) of the random decision variable Y in an ultrafast digital lightwave communication system, utilizing power-cubic all-optical nonlinear preprocessor is presented. The proposed model can replace the prevalent Gaussian approximation, as the accuracy of the latter is discredited by Monte-Carlo simulation. The Log-Pearson type-3 probability density function (LP3 pdf) is shown to appropriately represents the random decision variable Y. Three characteristic parameters of the LP3 pdf are also obtained through the three moments of the decision variable Y. Finally, the system error probability is revisited using the obtained LP3 pdf of the decision variable, the result of which is in excellent consistency with rigorous Monte-Carlo simulation.","PeriodicalId":166939,"journal":{"name":"2015 Iran Workshop on Communication and Information Theory (IWCIT)","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116021371","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 : 2015-05-06DOI: 10.1109/IWCIT.2015.7140216
M. Najafi, Vahid Jamah, R. Schober
In this paper, we consider the Gaussian interference channel consisting of two source-destination pairs where the sources cooperate to transmit their messages to their respective destination. We assume block fading and that the nodes are constrained to half-duplex operation. For this channel, assuming availability of channel state information (CSI), we determine the optimal adaptive scheduling of reception and transmission at the source nodes. Thereby, the proposed protocol chooses one of the information flows, decides whether to transmit directly or cooperatively to the corresponding destination, and specifies the required transmission strategy such that the achievable ergodic rate region is maximized. Numerical results reveal that the proposed protocol can effectively realize the diversity offered by the fading processes of the different links in the interference channel.
{"title":"Adaptive resource allocation for the fading interference channel with source cooperation","authors":"M. Najafi, Vahid Jamah, R. Schober","doi":"10.1109/IWCIT.2015.7140216","DOIUrl":"https://doi.org/10.1109/IWCIT.2015.7140216","url":null,"abstract":"In this paper, we consider the Gaussian interference channel consisting of two source-destination pairs where the sources cooperate to transmit their messages to their respective destination. We assume block fading and that the nodes are constrained to half-duplex operation. For this channel, assuming availability of channel state information (CSI), we determine the optimal adaptive scheduling of reception and transmission at the source nodes. Thereby, the proposed protocol chooses one of the information flows, decides whether to transmit directly or cooperatively to the corresponding destination, and specifies the required transmission strategy such that the achievable ergodic rate region is maximized. Numerical results reveal that the proposed protocol can effectively realize the diversity offered by the fading processes of the different links in the interference channel.","PeriodicalId":166939,"journal":{"name":"2015 Iran Workshop on Communication and Information Theory (IWCIT)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126828224","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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