Pub Date : 2015-06-14DOI: 10.1109/ISIT.2015.7282493
Ahmed Hindy, Aria Nosratinia
The performance of lattice codes in the additive white Gaussian noise (AWGN) channel has attracted much attention lately, however, their performance under ergodic fading channels has been relatively unexplored. We show that lattice coding and decoding achieve the capacity of the ergodic point-to-point and multiple-access channels (MAC). Additionally, a low-complexity scheme is proposed for the ergodic MAC. At moderate and high signal-to-noise ratio (SNR), the sum rate achieved by the low-complexity scheme is within a constant gap to the ergodic MAC sum capacity, whereas at low SNR the gap to capacity diminishes quadratically with linear SNR decrease.
{"title":"Achieving the ergodic capacity with lattice codes","authors":"Ahmed Hindy, Aria Nosratinia","doi":"10.1109/ISIT.2015.7282493","DOIUrl":"https://doi.org/10.1109/ISIT.2015.7282493","url":null,"abstract":"The performance of lattice codes in the additive white Gaussian noise (AWGN) channel has attracted much attention lately, however, their performance under ergodic fading channels has been relatively unexplored. We show that lattice coding and decoding achieve the capacity of the ergodic point-to-point and multiple-access channels (MAC). Additionally, a low-complexity scheme is proposed for the ergodic MAC. At moderate and high signal-to-noise ratio (SNR), the sum rate achieved by the low-complexity scheme is within a constant gap to the ergodic MAC sum capacity, whereas at low SNR the gap to capacity diminishes quadratically with linear SNR decrease.","PeriodicalId":272313,"journal":{"name":"2015 IEEE International Symposium on Information Theory (ISIT)","volume":"148 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123466804","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 : 2015-06-14DOI: 10.1109/ISIT.2015.7282950
Zhe Wang, V. Aggarwal, Xiaodong Wang
In this paper, we consider the energy-bandwidth allocation for a network with multiple orthogonal broadcast channels, where each transmitter communicates with multiple receivers orthogonally. We assume that the harvested energy and channel gain of each transmitter can be predicted for K slots a priori. To maximize the weighted throughput of the network, we formulate an optimization problem with O(MK) constraints, where M is the number of the receivers, making it hard to solve using a generic convex solver since the computational complexity of the solver becomes impractically high when the number of constraints is large. In order to use the iterative algorithm proposed in [1] to solve the problem efficiently, we decompose the problem into the energy and bandwidth allocation subproblems and propose algorithms to solve the two corresponding subproblems, so that the optimal energy-bandwidth allocation can be obtained with an overall complexity of O(MK2).
{"title":"Energy-bandwidth allocation in multiple orthogonal broadcast channels with energy harvesting","authors":"Zhe Wang, V. Aggarwal, Xiaodong Wang","doi":"10.1109/ISIT.2015.7282950","DOIUrl":"https://doi.org/10.1109/ISIT.2015.7282950","url":null,"abstract":"In this paper, we consider the energy-bandwidth allocation for a network with multiple orthogonal broadcast channels, where each transmitter communicates with multiple receivers orthogonally. We assume that the harvested energy and channel gain of each transmitter can be predicted for K slots a priori. To maximize the weighted throughput of the network, we formulate an optimization problem with O(MK) constraints, where M is the number of the receivers, making it hard to solve using a generic convex solver since the computational complexity of the solver becomes impractically high when the number of constraints is large. In order to use the iterative algorithm proposed in [1] to solve the problem efficiently, we decompose the problem into the energy and bandwidth allocation subproblems and propose algorithms to solve the two corresponding subproblems, so that the optimal energy-bandwidth allocation can be obtained with an overall complexity of O(MK2).","PeriodicalId":272313,"journal":{"name":"2015 IEEE International Symposium on Information Theory (ISIT)","volume":"282 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124513502","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 : 2015-06-14DOI: 10.1109/ISIT.2015.7282453
Y. M. Chee, Fei Gao, Samuel Tien Ho Teo, Hui Zhang
Multiport switches are commonly used as data processing and routing devices in computer networks. A network switch routes data packets between its multiple input and output ports. Packets from input ports are stored upon arrival in a switch fabric comprising multiple memory banks. This can lead to memory contention when distinct output ports request packets from the same memory bank, resulting in a degraded switching bandwidth. To solve this problem, switch codes are introduced by Wang et al. [1] as a tradeoff between redundancy and service. Using techniques from combinatorial design theory, we improve their result on switch codes serving any one-burst request to a denser set of parameters. New constructions for switch codes serving repetition limited request and consecutive-generation request are also given.
{"title":"Combinatorial systematic switch codes","authors":"Y. M. Chee, Fei Gao, Samuel Tien Ho Teo, Hui Zhang","doi":"10.1109/ISIT.2015.7282453","DOIUrl":"https://doi.org/10.1109/ISIT.2015.7282453","url":null,"abstract":"Multiport switches are commonly used as data processing and routing devices in computer networks. A network switch routes data packets between its multiple input and output ports. Packets from input ports are stored upon arrival in a switch fabric comprising multiple memory banks. This can lead to memory contention when distinct output ports request packets from the same memory bank, resulting in a degraded switching bandwidth. To solve this problem, switch codes are introduced by Wang et al. [1] as a tradeoff between redundancy and service. Using techniques from combinatorial design theory, we improve their result on switch codes serving any one-burst request to a denser set of parameters. New constructions for switch codes serving repetition limited request and consecutive-generation request are also given.","PeriodicalId":272313,"journal":{"name":"2015 IEEE International Symposium on Information Theory (ISIT)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121548378","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 : 2015-06-14DOI: 10.1109/ISIT.2015.7282576
Ximing Fu, Zhiqing Xiao, Shenghao Yang
In this paper, refined recovery and repair schemes are proposed for a storage system using the XOR-based MBR regenerating storage code proposed by Hou et al. Our schemes have zero transmission overhead for both recovery and repair, i.e., the total number of transmitted bits for repair/recovery is exactly equal to the total number of bits repaired/recovered. Further, our schemes use mainly XOR operations and have lower complexity than that of the previous schemes. Moreover, our schemes require only a small amount of auxiliary space, which qualifies our schemes as in-place.
{"title":"Overhead-free in-place recovery and repair schemes of XOR-based regenerating codes","authors":"Ximing Fu, Zhiqing Xiao, Shenghao Yang","doi":"10.1109/ISIT.2015.7282576","DOIUrl":"https://doi.org/10.1109/ISIT.2015.7282576","url":null,"abstract":"In this paper, refined recovery and repair schemes are proposed for a storage system using the XOR-based MBR regenerating storage code proposed by Hou et al. Our schemes have zero transmission overhead for both recovery and repair, i.e., the total number of transmitted bits for repair/recovery is exactly equal to the total number of bits repaired/recovered. Further, our schemes use mainly XOR operations and have lower complexity than that of the previous schemes. Moreover, our schemes require only a small amount of auxiliary space, which qualifies our schemes as in-place.","PeriodicalId":272313,"journal":{"name":"2015 IEEE International Symposium on Information Theory (ISIT)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125299235","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 : 2015-06-14DOI: 10.1109/ISIT.2015.7282891
Paula Aquilina, T. Ratnarajah
Topological interference management is the study of achievable rates within communication networks with no channel state information at the transmitter (CSIT) beyond knowledge of the network structure itself. In this paper, we consider topological interference management within the context of a two-cell two-user-per-cell interference broadcast channel (IBC) with alternating connectivity. Topological feedback, even though minimal, allows the transmitters to track the changing network topology and then exploit the varying connectivity states to obtain a degrees of freedom (DoF) gain. We derive novel outer bounds on the DoF achievable by the two-cell two-user-per-cell IBC with alternating connectivity. The analysis initially focuses on the single-input single-output (SISO) case and is later extended to multiple-input single-output (MISO) and multiple-input multiple-output (MIMO) systems. While global channel knowledge is restricted to topological information only, varying degrees of local CSIT availability are considered, depending on the network configuration. Additionally, we investigate the achievability of the derived bounds and for the case where all alternating connectivity states are equiprobable propose new transmission schemes based on joint coding across states.
{"title":"Topological interference management for interference broadcast channels with alternating connectivity","authors":"Paula Aquilina, T. Ratnarajah","doi":"10.1109/ISIT.2015.7282891","DOIUrl":"https://doi.org/10.1109/ISIT.2015.7282891","url":null,"abstract":"Topological interference management is the study of achievable rates within communication networks with no channel state information at the transmitter (CSIT) beyond knowledge of the network structure itself. In this paper, we consider topological interference management within the context of a two-cell two-user-per-cell interference broadcast channel (IBC) with alternating connectivity. Topological feedback, even though minimal, allows the transmitters to track the changing network topology and then exploit the varying connectivity states to obtain a degrees of freedom (DoF) gain. We derive novel outer bounds on the DoF achievable by the two-cell two-user-per-cell IBC with alternating connectivity. The analysis initially focuses on the single-input single-output (SISO) case and is later extended to multiple-input single-output (MISO) and multiple-input multiple-output (MIMO) systems. While global channel knowledge is restricted to topological information only, varying degrees of local CSIT availability are considered, depending on the network configuration. Additionally, we investigate the achievability of the derived bounds and for the case where all alternating connectivity states are equiprobable propose new transmission schemes based on joint coding across states.","PeriodicalId":272313,"journal":{"name":"2015 IEEE International Symposium on Information Theory (ISIT)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122409332","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 : 2015-06-14DOI: 10.1109/ISIT.2015.7282902
H. Morita
We propose a new class of single error correcting linear codes suitable for a two dimensional hexagonal constellation. The proposed code is a linear subspace of ℤ6n+1n where n is code length and 6n + 1 is a prime number. It corrects a single error in the set |±1, ±αn, ±α2n} where α is a primitive element of ℤ6n+1x. Moreover, we apply the proposed code to a two dimensional hexagonal constellation and show that it corrects an error such that a transmitted symbol moves to one of its nearest neighbors over the hexagonal constellation at the decoder side. We also consider an extension of the proposed code to double nearest neighbor error correcting codes. Some examples of such codes obtained by computer-assisted search are presented.
{"title":"Nearest-neighbor error correcting codes on a hexagonal signal constellation","authors":"H. Morita","doi":"10.1109/ISIT.2015.7282902","DOIUrl":"https://doi.org/10.1109/ISIT.2015.7282902","url":null,"abstract":"We propose a new class of single error correcting linear codes suitable for a two dimensional hexagonal constellation. The proposed code is a linear subspace of ℤ<sub>6n+1</sub><sup>n</sup> where n is code length and 6n + 1 is a prime number. It corrects a single error in the set |±1, ±α<sup>n</sup>, ±α<sup>2n</sup>} where α is a primitive element of ℤ<sub>6n+1</sub><sup>x</sup>. Moreover, we apply the proposed code to a two dimensional hexagonal constellation and show that it corrects an error such that a transmitted symbol moves to one of its nearest neighbors over the hexagonal constellation at the decoder side. We also consider an extension of the proposed code to double nearest neighbor error correcting codes. Some examples of such codes obtained by computer-assisted search are presented.","PeriodicalId":272313,"journal":{"name":"2015 IEEE International Symposium on Information Theory (ISIT)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128480693","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 : 2015-06-14DOI: 10.1109/ISIT.2015.7282732
Dmitri S. Pavlichin
Given a finite set S and a group G acting on S, a probability distribution on S is G-invariant, or symmetric, if it is constant on the orbits of the group action. How can one symmetrize a non-symmetric probability distribution - i.e. find the “nearest” G-invariant distribution? When would one want to? We find that for the Rényi and Bregman divergences, symmetrization means averaging over the group orbits in a natural way; for the special case of the Kullback-Leibler divergence, relevant in maximum likelihood inference and in large deviations, symmetrization is either the arithmetic or geometric average, depending on the order of arguments. We apply our results for the symmetries of time-reversibility and exchangeability for Markov chains to answer questions in inference and in large deviations: given some data, what is the maximum likelihood time-reversible Markov chain? How long must we “watch” a trajectory from a Markov chain to establish whether time is running forward or in reverse? What does the data look like conditioned on a time-reversal fluctuation?
{"title":"Nearest symmetric distributions","authors":"Dmitri S. Pavlichin","doi":"10.1109/ISIT.2015.7282732","DOIUrl":"https://doi.org/10.1109/ISIT.2015.7282732","url":null,"abstract":"Given a finite set S and a group G acting on S, a probability distribution on S is G-invariant, or symmetric, if it is constant on the orbits of the group action. How can one symmetrize a non-symmetric probability distribution - i.e. find the “nearest” G-invariant distribution? When would one want to? We find that for the Rényi and Bregman divergences, symmetrization means averaging over the group orbits in a natural way; for the special case of the Kullback-Leibler divergence, relevant in maximum likelihood inference and in large deviations, symmetrization is either the arithmetic or geometric average, depending on the order of arguments. We apply our results for the symmetries of time-reversibility and exchangeability for Markov chains to answer questions in inference and in large deviations: given some data, what is the maximum likelihood time-reversible Markov chain? How long must we “watch” a trajectory from a Markov chain to establish whether time is running forward or in reverse? What does the data look like conditioned on a time-reversal fluctuation?","PeriodicalId":272313,"journal":{"name":"2015 IEEE International Symposium on Information Theory (ISIT)","volume":"4 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130497740","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 : 2015-06-14DOI: 10.1109/ISIT.2015.7282856
T. Courtade, Ayfer Özgür
Beginning with work by Avestimehr, Diggavi and Tse, there have been a series of papers showing that the capacity of Gaussian relay networks can be closely approximated by the cutset bound. More precisely, it is known that the gap between the cutset bound and capacity in these networks can be bounded by a function that grows linearly with the number of nodes in the network and is otherwise independent of network topology and channel configurations. We argue that this linear gap is fundamental to such approximations, and prove that improvement to a sublinear function is possible if, and only if, capacity is equal to the cutset bound for all Gaussian relay networks.
{"title":"Approximate capacity of Gaussian relay networks: Is a sublinear gap to the cutset bound plausible?","authors":"T. Courtade, Ayfer Özgür","doi":"10.1109/ISIT.2015.7282856","DOIUrl":"https://doi.org/10.1109/ISIT.2015.7282856","url":null,"abstract":"Beginning with work by Avestimehr, Diggavi and Tse, there have been a series of papers showing that the capacity of Gaussian relay networks can be closely approximated by the cutset bound. More precisely, it is known that the gap between the cutset bound and capacity in these networks can be bounded by a function that grows linearly with the number of nodes in the network and is otherwise independent of network topology and channel configurations. We argue that this linear gap is fundamental to such approximations, and prove that improvement to a sublinear function is possible if, and only if, capacity is equal to the cutset bound for all Gaussian relay networks.","PeriodicalId":272313,"journal":{"name":"2015 IEEE International Symposium on Information Theory (ISIT)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130924738","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 : 2015-06-14DOI: 10.1109/ISIT.2015.7282520
Islam El Bakoury, B. Nazer
Consider several single-antenna transmitters that wish to simultaneously communicate with a multiple-antenna receiver. Recent work has proposed the integer-forcing linear receiver architecture as an alternative to conventional linear receivers. The key idea is to first use linear equalization to obtain an integer-valued effective channel, then employ single-user decoders to recover integer-linear combinations of the messages, and finally solve these for the desired messages. For the special case where the channel matrix remains fixed for the duration of the codeword, it has been shown that integer-forcing can operate very close to the performance of optimal joint maximum likelihood decoding. In this paper, we investigate the impact of channel variation on the integer-forcing linear receiver and show it still retains an advantage over conventional linear receivers, despite the fact that the integer coefficients must remain fixed across the codeword duration.
{"title":"The impact of channel variation on integer-forcing receivers","authors":"Islam El Bakoury, B. Nazer","doi":"10.1109/ISIT.2015.7282520","DOIUrl":"https://doi.org/10.1109/ISIT.2015.7282520","url":null,"abstract":"Consider several single-antenna transmitters that wish to simultaneously communicate with a multiple-antenna receiver. Recent work has proposed the integer-forcing linear receiver architecture as an alternative to conventional linear receivers. The key idea is to first use linear equalization to obtain an integer-valued effective channel, then employ single-user decoders to recover integer-linear combinations of the messages, and finally solve these for the desired messages. For the special case where the channel matrix remains fixed for the duration of the codeword, it has been shown that integer-forcing can operate very close to the performance of optimal joint maximum likelihood decoding. In this paper, we investigate the impact of channel variation on the integer-forcing linear receiver and show it still retains an advantage over conventional linear receivers, despite the fact that the integer coefficients must remain fixed across the codeword duration.","PeriodicalId":272313,"journal":{"name":"2015 IEEE International Symposium on Information Theory (ISIT)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130576738","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 : 2015-06-14DOI: 10.1109/ISIT.2015.7282456
I. Zhilin, P. Rybin, V. Zyablov
In this paper we propose to consider a generalized error-locating code (GEL-code) as a possible candidate for data transmission systems that require high code rates along with strict requirements on wrong decoding probability. GEL codes are one of a few that allow analytical computation of code error probability bounds and have practical construction method. The paper describes the construction of the GEL-code and the algorithms for encoding and decoding. It represents the upper and lower bounds on wrong decoding probability. It gives a method for constructing such GEL code (with the minimal redundancy) that guarantees that the probability of wrong decoding will be less than required one (for a given channel error probability). Numerical results for the upper and lower bounds for the various GEL-codes and the analysis of the energy gain for the different signal-code structures are given.
{"title":"High-rate codes for high-reliability data transmission","authors":"I. Zhilin, P. Rybin, V. Zyablov","doi":"10.1109/ISIT.2015.7282456","DOIUrl":"https://doi.org/10.1109/ISIT.2015.7282456","url":null,"abstract":"In this paper we propose to consider a generalized error-locating code (GEL-code) as a possible candidate for data transmission systems that require high code rates along with strict requirements on wrong decoding probability. GEL codes are one of a few that allow analytical computation of code error probability bounds and have practical construction method. The paper describes the construction of the GEL-code and the algorithms for encoding and decoding. It represents the upper and lower bounds on wrong decoding probability. It gives a method for constructing such GEL code (with the minimal redundancy) that guarantees that the probability of wrong decoding will be less than required one (for a given channel error probability). Numerical results for the upper and lower bounds for the various GEL-codes and the analysis of the energy gain for the different signal-code structures are given.","PeriodicalId":272313,"journal":{"name":"2015 IEEE International Symposium on Information Theory (ISIT)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130703367","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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