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Information Theory, IEEE Transactions on

Issue 8 • Date Aug. 2014

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Displaying Results 1 - 25 of 43
  • Table of contents

    Page(s): C1 - C4
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    Freely Available from IEEE
  • IEEE Transactions on Information Theory publication information

    Page(s): C2
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    Freely Available from IEEE
  • Moderate Deviations in Channel Coding

    Page(s): 4417 - 4426
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (247 KB) |  | HTML iconHTML  

    We consider block codes whose rate converges to the channel capacity with increasing blocklength at a certain speed and examine the best possible decay of the probability of error. For discrete memoryless channels, we prove that a moderate deviation principle holds for all convergence rates between the large deviation and the central limit theorem regimes. View full abstract»

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  • Second-Order Coding Rates for Channels With State

    Page(s): 4427 - 4448
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (485 KB) |  | HTML iconHTML  

    We study the performance limits of state-dependent discrete memoryless channels with a discrete state available at both the encoder and the decoder. We establish the ε-capacity as well as necessary and sufficient conditions for the strong converse property for such channels when the sequence of channel states is not necessarily stationary, memoryless, or ergodic. We then seek a finer characterization of these capacities in terms of second-order coding rates. The general results are supplemented by several examples including independent identically distributed and Markov states and mixed channels. View full abstract»

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  • Expurgated Random-Coding Ensembles: Exponents, Refinements, and Connections

    Page(s): 4449 - 4462
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (422 KB) |  | HTML iconHTML  

    This paper studies expurgated random-coding bounds and exponents for channel coding with a given (possibly suboptimal) decoding rule. Variations of Gallager's analysis are presented, yielding several asymptotic and nonasymptotic bounds on the error probability for an arbitrary codeword distribution. A simple nonasymptotic bound is shown to attain an exponent of Csiszár and Körner under constant-composition coding. Using Lagrange duality, this exponent is expressed in several forms, one of which is shown to permit a direct derivation via cost-constrained coding that extends to infinite and continuous alphabets. The method of type class enumeration is studied, and it is shown that this approach can yield improved exponents and better tightness guarantees for some codeword distributions. A generalization of this approach is shown to provide a multiletter exponent that extends immediately to channels with memory. View full abstract»

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  • Erasure/List Exponents for Slepian–Wolf Decoding

    Page(s): 4463 - 4471
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (289 KB) |  | HTML iconHTML  

    We analyze random coding error exponents associated with erasure/list Slepian-Wolf decoding using two different methods and then compare the resulting bounds. The first method follows the well known techniques of Gallager and Forney and the second method is based on a technique of distance enumeration, or more generally, type class enumeration, which is rooted in the statistical mechanics of a disordered system that is related to the random energy model. The second method is guaranteed to yield exponent functions, which are at least as tight as those of the first method, and it is demonstrated that for certain combinations of coding rates and thresholds, the bounds of the second method are strictly tighter than those of the first method, by an arbitrarily large factor. The second method may even yield an infinite exponent at regions where the first method gives finite values. View full abstract»

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  • List Decoding for Arbitrarily Varying Broadcast Channels With Receiver Side Information

    Page(s): 4472 - 4487
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (498 KB) |  | HTML iconHTML  

    In this paper, the discrete memoryless arbitrarily varying broadcast channel (AVBC) with receiver side information is studied and its random code and deterministic code capacity regions are derived for the average error criterion. In addition, it is analyzed for deterministic list codes and it is shown that the corresponding list capacity region displays a behavior, which is similar to Ahlswede's famous dichotomy result for the single-user arbitrarily varying channel: it either equals the random code capacity region or otherwise has an empty interior. This is characterized in terms of list sizes at the receivers and an appropriate concept of symmetrizability for the AVBC with receiver side information. The scenario studied here is motivated by the broadcast phase of bidirectional relaying, where a half-duplex relay node establishes a bidirectional communication between two other nodes using a decode-and-forward protocol. The relay decodes the messages both nodes have sent in the initial multiple access phase and broadcasts a re-encoded composition of them in the succeeding broadcast phase. Then, the broadcast phase corresponds to the AVBC with receiver side information, which differs from the classical broadcast channel, since both receivers can exploit their own messages from the previous phase as side information for decoding. View full abstract»

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  • Communication With Disturbance Constraints

    Page(s): 4488 - 4502
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    Motivated by the broadcast view of the interference channel, the new problem of communication with disturbance constraints is formulated. The rate-disturbance region is established for the single constraint case and the optimal encoding scheme turns out to be the same as the Han-Kobayashi scheme for the two user-pair interference channel. This result is extended to the Gaussian vector (multiple-input and multiple-output) case. For the case of communication with two disturbance constraints, inner and outer bounds on the rate-disturbance region for a deterministic model are established. The inner bound is achieved by an encoding scheme that involves rate splitting, Marton coding, and superposition coding, and is shown to be optimal in several nontrivial cases. This encoding scheme can be readily applied to discrete memoryless interference channels and motivates a natural extension of the Han-Kobayashi scheme to more than two user pairs. View full abstract»

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  • Sumset and Inverse Sumset Inequalities for Differential Entropy and Mutual Information

    Page(s): 4503 - 4514
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (242 KB) |  | HTML iconHTML  

    The sumset and inverse sumset theories of Freiman, Plünnecke, and Ruzsa, give bounds connecting the cardinality of the sumset A + B = {a + b; a ∈ A, b ∈ B} of two discrete sets A, B, to the cardinalities (or the finer structure) of the original sets A, B. For example, the sum-difference bound of Ruzsa states that, |A + B| |A| |B| |A - B|3, where the difference set A - B = {a - b; a ∈ A, b ∈ B}. Interpreting the differential entropy h(X) of a continuous random variable X as (the logarithm of) the size of the effective support of X, the main contribution of this paper is a series of natural information-theoretic analogs for these results. For example, the Ruzsa sum-difference bound becomes the new inequality, h(X+Y)+h(X)+h(Y) ≤ 3h(X-Y), for any pair of independent continuous random variables X and Y. Our results include differential-entropy versions of Ruzsa's triangle inequality, the Plünnecke-Ruzsa inequality, and the Balog-Szemerédi-Gowers lemma. In addition, we give a differential entropy version of a Freiman-type inverse-sumset theorem, which can be seen as a quantitative converse to the entropy power inequality. Versions of most of these results for the discrete entropy H(X) were recently proved by Tao, relying heavily on a strong, functional form of the submodularity property of H(X). Since differential entropy is not functionally submodular, in the continuous case many of the corresponding discrete proofs fail, in many cases requiring substantially new proof strategies. We find that the basic property that naturally replaces the discrete functional submodularity, is the data processing property of mutual information. View full abstract»

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  • Which Boolean Functions Maximize Mutual Information on Noisy Inputs?

    Page(s): 4515 - 4525
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (499 KB) |  | HTML iconHTML  

    We pose a simply stated conjecture regarding the maximum mutual information a Boolean function can reveal about noisy inputs. Specifically, let Xn be independent identically distributed Bernoulli(1/2), and let Yn be the result of passing Xn through a memoryless binary symmetric channel with crossover probability α. For any Boolean function b : {0, 1}n → {0, 1}, we conjecture that I(b(Xn); Yn) ≤ 1 - H(α). While the conjecture remains open, we provide substantial evidence supporting its validity. Connections are also made to discrete isoperimetric inequalities. View full abstract»

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  • Finite-Memory Prediction as Well as the Empirical Mean

    Page(s): 4526 - 4543
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1571 KB) |  | HTML iconHTML  

    The problem of universally predicting an individual continuous sequence using a deterministic finite-state machine (FSM) is considered. The empirical mean is used as a reference as it is the constant that fits a given sequence within a minimal square error. A reasonable prediction performance is the regret, namely the excess square-error over the reference loss. This paper analyzes the tradeoff between the number of states of the universal FSM and the attainable regret. This paper first studies the case of a small number of states. A class of machines, termed degenerated tracking memory (DTM), is defined and shown to be optimal for small enough number of states. Unfortunately, DTM machines become suboptimal and their regret does not vanish as the number of available states increases. Next, the exponential decaying memory (EDM) machine, previously used for predicting binary sequences, is considered. While the EDM machine has poorer performance for small number of states, it achieves a vanishing regret for large number of states. Following that, an asymptotic lower bound of O(k-2/3) on the achievable regret of any k-state machine is derived. This bound is attained asymptotically by the EDM machine. Finally, the enhanced exponential decaying memory machine is presented and shown to outperform the EDM machine for any number of states. View full abstract»

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  • Quantization of Binary-Input Discrete Memoryless Channels

    Page(s): 4544 - 4552
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (706 KB) |  | HTML iconHTML  

    The quantization of the output of a binary-input discrete memoryless channel to a smaller number of levels is considered. An algorithm, which finds an optimal quantizer, in the sense of maximizing mutual information between the channel input and quantizer output is given. This result holds for arbitrary channels, in contrast to previous results for restricted channels or a restricted number of quantizer outputs. In the worst case, the algorithm complexity is cubic M3 in the number of channel outputs M. Optimality is proved using the theorem of Burshtein, Della Pietra, Kanevsky, and Nádas for mappings, which minimize average impurity for classification and regression trees. View full abstract»

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  • Insufficiency of Linear-Feedback Schemes in Gaussian Broadcast Channels With Common Message

    Page(s): 4553 - 4566
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (636 KB) |  | HTML iconHTML  

    We consider the K ≥ 2-user memoryless Gaussian broadcast channel (BC) with feedback and common message only. We show that linear-feedback schemes with a message point, in the spirit of Schalkwijk and Kailath's scheme for point-to-point channels or Ozarow and Leung's scheme for BCs with private messages, are strictly suboptimal for this setup. Even with perfect feedback, the largest rate achieved by these schemes is strictly smaller than capacity C (which is the same with and without feedback). In the extreme case where the number of receivers K → ∞, the largest rate achieved by linear-feedback schemes with a message point tends to 0. To contrast this negative result, we describe a scheme for rate-limited feedback that uses the feedback in an intermittent way, i.e., the receivers send feedback signals only in few channel uses. This scheme achieves all rates R up to capacity C with an Lth order exponential decay of the probability of error if the feedback rate Rfb is at least (L - 1)R for some positive integer L. View full abstract»

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  • On the Relationships Among Optimal Symmetric Fix-Free Codes

    Page(s): 4567 - 4583
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (661 KB) |  | HTML iconHTML  

    Symmetric fix-free codes are prefix condition codes in which each codeword is required to be a palindrome. Their study is motivated by the topic of joint source-channel coding and by some information retrieval problems. Although they have been considered by a few communities they are not well understood. In earlier work, we used a collection of instances of Boolean satisfiability problems as a tool in the generation of all optimal binary symmetric fix-free codes with n codewords and observed that the number of different optimal codelength sequences grows slowly compared with the corresponding number for prefix condition codes. We demonstrate that all optimal symmetric fixfree codes can alternatively be obtained by sequences of codes generated by simple manipulations starting from one particular code. We also discuss simplifications in the process of searching for this set of codes as well as a conjecture, which if correct, together with the other results leads to a relatively fast algorithm which has been implemented in MATLAB to construct all optimal binary symmetric fix-free codes. View full abstract»

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  • Zero-Delay Sequential Transmission of Markov Sources Over Burst Erasure Channels

    Page(s): 4584 - 4613
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2522 KB) |  | HTML iconHTML  

    A setup involving zero-delay sequential transmission of a vector Markov source over a burst erasure channel is studied. A sequence of source vectors is compressed in a causal fashion at the encoder, and the resulting output is transmitted over a burst erasure channel. The destination is required to reconstruct each source vector with zero-delay, but those source sequences that are observed either during the burst erasure, or in the interval of length W following the burst erasure need not be reconstructed. The minimum achievable compression rate is called the rate-recovery function. We assume that each source vector is independent identically distributed (i.i.d.) across the spatial dimension and is sampled from a stationary, first-order Markov process across the temporal dimension. For discrete sources, the case of lossless recovery is considered, and upper and lower bounds on the rate-recovery function are established. Both these bounds can be expressed as the rate for predictive coding, plus a term that decreases at least inversely with the recovery window length W. For Gauss-Markov sources and a quadratic distortion measure, upper and lower bounds on the minimum rate are established when W = 0. These bounds are shown to coincide in the high resolution limit. Finally, another setup involving i.i.d. Gaussian sources is studied and the raterecovery function is completely characterized in this case. View full abstract»

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  • Semiquantitative Group Testing

    Page(s): 4614 - 4636
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1703 KB) |  | HTML iconHTML  

    We propose a novel group testing method, termed semiquantitative group testing (SQGT), motivated by a class of problems arising in genome screening experiments. The SQGT is a (possibly) nonbinary pooling scheme that may be viewed as a concatenation of an adder channel and an integer-valued quantizer. In its full generality, SQGT may be viewed as a unifying framework for group testing, in the sense that most group testing models are special instances of SQGT. For the new testing scheme, we define the notion of SQ-disjunct and SQ-separable codes, representing generalizations of classical disjunct and separable codes. We describe several combinatorial and probabilistic constructions for such codes. While for most of these constructions, we assume that the number of defectives is much smaller than total number of test subjects, we also consider the case in which there is no restriction on the number of defectives and they may be as large as the total number of subjects. For the codes constructed in this paper, we describe a number of efficient decoding algorithms. In addition, we describe a belief propagation decoder for sparse SQGT codes for which no other efficient decoder is currently known. View full abstract»

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  • Codes With Local Regeneration and Erasure Correction

    Page(s): 4637 - 4660
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1673 KB) |  | HTML iconHTML  

    Regenerating codes and codes with locality are two coding schemes that have recently been proposed, which in addition to ensuring data collection and reliability, also enable efficient node repair. In a situation where one is attempting to repair a failed node, regenerating codes seek to minimize the amount of data downloaded for node repair, while codes with locality attempt to minimize the number of helper nodes accessed. This paper presents results in two directions. In one, this paper extends the notion of codes with locality so as to permit local recovery of an erased code symbol even in the presence of multiple erasures, by employing local codes having minimum distance >2. An upper bound on the minimum distance of such codes is presented and codes that are optimal with respect to this bound are constructed. The second direction seeks to build codes that combine the advantages of both codes with locality as well as regenerating codes. These codes, termed here as codes with local regeneration, are codes with locality over a vector alphabet, in which the local codes themselves are regenerating codes. We derive an upper bound on the minimum distance of vector-alphabet codes with locality for the case when their constituent local codes have a certain uniform rank accumulation property. This property is possessed by both minimum storage regeneration (MSR) and minimum bandwidth regeneration (MBR) codes. We provide several constructions of codes with local regeneration which achieve this bound, where the local codes are either MSR or MBR codes. Also included in this paper, is an upper bound on the minimum distance of a general vector code with locality as well as the performance comparison of various code constructions of fixed block length and minimum distance. View full abstract»

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  • A Family of Optimal Locally Recoverable Codes

    Page(s): 4661 - 4676
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (326 KB) |  | HTML iconHTML  

    A code over a finite alphabet is called locally recoverable (LRC) if every symbol in the encoding is a function of a small number (at most r ) other symbols. We present a family of LRC codes that attain the maximum possible value of the distance for a given locality parameter and code cardinality. The codewords are obtained as evaluations of specially constructed polynomials over a finite field, and reduce to a Reed-Solomon code if the locality parameter r is set to be equal to the code dimension. The size of the code alphabet for most parameters is only slightly greater than the code length. The recovery procedure is performed by polynomial interpolation over r points. We also construct codes with several disjoint recovering sets for every symbol. This construction enables the system to conduct several independent and simultaneous recovery processes of a specific symbol by accessing different parts of the codeword. This property enables high availability of frequently accessed data (“hot data”). View full abstract»

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  • Linear Programming Decoding of Spatially Coupled Codes

    Page(s): 4677 - 4698
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1103 KB) |  | HTML iconHTML  

    For a given family of spatially coupled codes, we prove that the linear programming (LP) threshold on the binary-symmetric channel (BSC) of the tail-biting graph cover ensemble is the same as the LP threshold on the BSC of the derived spatially coupled ensemble. This result is in contrast with the fact that spatial coupling significantly increases the belief propagation threshold. To prove this, we establish some properties related to the dual witness for LP decoding. More precisely, we prove that the existence of a dual witness, which was previously known to be sufficient for LP decoding success, is also necessary and is equivalent to the existence of certain acyclic hyperflows. We also derive a sublinear (in the block length) upper bound on the weight of any edge in such hyperflows, both for regular low-density parity-check (LPDC) codes and spatially coupled codes and we prove that the bound is asymptotically tight for regular LDPC codes. Moreover, we show how to trade crossover probability for LP excess on all the variable nodes, for any binary linear code. View full abstract»

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  • Upper Bounds on the Size of Grain-Correcting Codes

    Page(s): 4699 - 4709
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (652 KB) |  | HTML iconHTML  

    In this paper, we revisit the combinatorial error model of Mazumdar et al. that models errors in high-density magnetic recording caused by lack of knowledge of grain boundaries in the recording medium. We present new upper bounds on the cardinality/rate of binary block codes that correct errors within this model. All our bounds, except for one, are obtained using combinatorial arguments based on hypergraph fractional coverings. The exception is a bound derived via an information-theoretic argument. Our bounds significantly improve upon existing bounds from the prior literature. View full abstract»

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  • The Weight Distributions of Several Classes of Cyclic Codes From APN Monomials

    Page(s): 4710 - 4721
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1568 KB) |  | HTML iconHTML  

    Let m ≥ 3 be an odd integer and p be an odd prime. In this paper, a number of classes of three-weight cyclic codes C(1,e) over Fp, which have parity-check polynomial m1(x)me(x), are presented by examining general conditions on the parameters p, m, and e, where mi(x) is the minimal polynomial of π-i over Fp for a primitive element π of Fpm. Furthermore, for p ≡ 3 (mod 4) and a positive integer e satisfying (pk + 1) · e ≡ 2 (mod pm - 1) for some positive integer k with gcd(m, k) = 1, the value distributions of the exponential sums T(a, b) = Σx∈Fpm ωTr(ax+bxe) and S(a, b, c) = Σx∈Fpm ωTr(ax+bxe+cxs), where s = (pm - 1)/2, are determined. As an application, the value distribution of S(a, b, c) is utilized to derive the weight distribution of the cyclic codes C(1,e,s) with parity-check polynomial m1(x)me(x)ms(x). In the case of p = 3 and even e satisfying the above condition, the dual of the cyclic code C(1,e,s) has optimal minimum distance. View full abstract»

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  • Accessible Capacity of Secondary Users

    Page(s): 4722 - 4738
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2336 KB) |  | HTML iconHTML  

    A new problem formulation is presented for the Gaussian interference channels with two pairs of users, which are distinguished as primary users and secondary users, respectively. The primary users employ a pair of encoder and decoder that were originally designed to satisfy a given error performance requirement under the assumption that no interference exists from other users. In the scenario when the secondary users attempt to access the same medium, we are interested in the maximum transmission rate (defined as accessible capacity) at which secondary users can communicate reliably without affecting the error performance requirement by the primary users under the constraint that the primary encoder (not the decoder) is kept unchanged. By modeling the primary encoder as a generalized trellis code (GTC), we are then able to treat the secondary link and the cross link from the secondary transmitter to the primary receiver as finite state channels. Based on this, upper and lower bounds on the accessible capacity are derived. The impact of the error performance requirement by the primary users on the accessible capacity is analyzed by using the concept of interference margin. In the case of nontrivial interference margin, the secondary message is split into common and private parts and then encoded by superposition coding, which delivers a lower bound on the accessible capacity. For some special cases, these bounds can be computed numerically by using the BCJR algorithm. Numerical results are also provided to gain insight into the impacts of the GTC and the error performance requirement on the accessible capacity. View full abstract»

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  • Channel Capacity Under Sub-Nyquist Nonuniform Sampling

    Page(s): 4739 - 4756
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1767 KB) |  | HTML iconHTML  

    This paper investigates the effect of sub-Nyquist sampling upon the capacity of an analog channel. The channel is assumed to be a linear time-invariant Gaussian channel, where perfect channel knowledge is available at both the transmitter and the receiver. We consider a general class of right-invertible time-preserving sampling methods which includes irregular nonuniform sampling, and characterize in closed form the channel capacity achievable by this class of sampling methods, under a sampling rate and power constraint. Our results indicate that the optimal sampling structures extract out the set of frequencies that exhibits the highest signal-to-noise ratio among all spectral sets of measure equal to the sampling rate. This can be attained through filterbank sampling with uniform sampling grid employed at each branch with possibly different rates, or through a single branch of modulation and filtering followed by uniform sampling. These results reveal that for a large class of channels, employing irregular nonuniform sampling sets, while are typically complicated to realize in practice, does not provide capacity gain over uniform sampling sets with appropriate preprocessing. Our findings demonstrate that aliasing or scrambling of spectral components does not provide capacity gain in this scenario, which is in contrast to the benefits obtained from random mixing in spectrum-blind compressive sampling schemes. View full abstract»

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  • Multiple-Antenna Interference Channels With Real Interference Alignment and Receive Antenna Joint Processing Based on Simultaneous Diophantine Approximation

    Page(s): 4757 - 4769
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (509 KB) |  | HTML iconHTML  

    In this paper, the degrees of freedom (DoF) regions of constant coefficient multiple antenna interference channels are investigated. First, we consider a K-user Gaussian interference channel with Mk antennas at transmitter k, 1 ≤ k ≤ K, and Nj antennas at receiver j, 1 ≤ j ≤ K, denoted as a (K, [Mk], [Nj]) channel. Relying on a result of simultaneous Diophantine approximation, a real interference alignment scheme with joint receive antenna processing is developed. The scheme is used to obtain an achievable DoF region. The proposed DoF region includes two previously known results as special cases, namely: 1) the total DoF of (K, [N], [N]) interference channel with K users and N antennas at each node is NK/2 and 2) the total DoF of a (K, [M], [N]) channel is at least KMN/(M+N). We next explore constant-coefficient interference networks with K transmitters and J receivers, all having N antennas. Each transmitter emits an independent message and each receiver requests an arbitrary subset of the messages. Employing the novel joint receive antenna processing, the DoF region for this setup is obtained. We finally consider wireless X networks where each node is allowed to have an arbitrary number of antennas. It is shown that the joint receive antenna processing can be used to establish an achievable DoF region, which is larger than what is possible with antenna splitting. As a special case of the derived achievable DoF region for constant coefficient X network, the total DoF of wireless X networks with the same number of antennas at all nodes and with joint antenna processing is tight while the best inner bound based on antenna splitting cannot meet the outer bound. Finally, we obtain a DoF region outer bound based on the technique of transmitter grouping. View full abstract»

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  • Interference Mitigation and Signal Enhancement for Multiuser MIMO Interference Channels With Redundant Antennas

    Page(s): 4770 - 4785
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (524 KB) |  | HTML iconHTML  

    For a transceiver pair in a multiuser Gaussian interference channel with multiple antennas, if the number of transmit antennas is greater than the number of receive antennas, then in an equivalent virtual channel this transceiver pair has redundant transmit antennas. These redundant antennas do not contribute to the transmission to the intended receiver, however, may generate interference to other receivers. The optimal way to use these redundant antennas to mitigate interference and enhance the useful signal is studied, under the assumption of perfect channel state information, channel distribution information, and imperfect channel state information at the transmitter side, respectively. View full abstract»

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Aims & Scope

IEEE Transactions on Information Theory publishes papers concerned with the transmission, processing, and utilization of information.

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Meet Our Editors

Editor-in-Chief
Frank R. Kschischang

Department of Electrical and Computer Engineering