Unnamed: 0
int64
0
41k
title
stringlengths
4
274
category
stringlengths
5
18
summary
stringlengths
22
3.66k
theme
stringclasses
8 values
1,600
On Bounded-Weight Error-Correcting Codes
cs.IT
This paper computationally obtains optimal bounded-weight, binary, error-correcting codes for a variety of distance bounds and dimensions. We compare the sizes of our codes to the sizes of optimal constant-weight, binary, error-correcting codes, and evaluate the differences.
math
1,601
Long Nonbinary Codes Exceeding the Gilbert - Varshamov Bound for any Fixed Distance
cs.IT
Let A(q,n,d) denote the maximum size of a q-ary code of length n and distance d. We study the minimum asymptotic redundancy \rho(q,n,d)=n-log_q A(q,n,d) as n grows while q and d are fixed. For any d and q<=d-1, long algebraic codes are designed that improve on the BCH codes and have the lowest asymptotic redundancy \rh...
math
1,602
On Expanders Graphs: Parameters and Applications
cs.IT
We give a new lower bound on the expansion coefficient of an edge-vertex graph of a $d$-regular graph. As a consequence, we obtain an improvement on the lower bound on relative minimum distance of the expander codes constructed by Sipser and Spielman. We also derive some improved results on the vertex expansion of grap...
math
1,603
Improved error bounds for the erasure/list scheme: the binary and spherical cases
cs.IT
We derive improved bounds on the error and erasure rate for spherical codes and for binary linear codes under Forney's erasure/list decoding scheme and prove some related results.
math
1,604
Distance distribution of binary codes and the error probability of decoding
cs.IT
We address the problem of bounding below the probability of error under maximum likelihood decoding of a binary code with a known distance distribution used on a binary symmetric channel. An improved upper bound is given for the maximum attainable exponent of this probability (the reliability function of the channel). ...
math
1,605
Iterative Quantization Using Codes On Graphs
cs.IT
We study codes on graphs combined with an iterative message passing algorithm for quantization. Specifically, we consider the binary erasure quantization (BEQ) problem which is the dual of the binary erasure channel (BEC) coding problem. We show that duals of capacity achieving codes for the BEC yield codes which appro...
math
1,606
Improved Upper Bound for the Redundancy of Fix-Free Codes
cs.IT
A variable-length code is a fix-free code if no codeword is a prefix or a suffix of any other codeword. In a fix-free code any finite sequence of codewords can be decoded in both directions, which can improve the robustness to channel noise and speed up the decoding process. In this paper we prove a new sufficient cond...
math
1,607
The Dynamics of Group Codes: Dual Abelian Group Codes and Systems
cs.IT
Fundamental results concerning the dynamics of abelian group codes (behaviors) and their duals are developed. Duals of sequence spaces over locally compact abelian groups may be defined via Pontryagin duality; dual group codes are orthogonal subgroups of dual sequence spaces. The dual of a complete code or system is fi...
math
1,608
Source Coding With Distortion Side Information At The Encoder
cs.IT
We consider lossy source coding when side information affecting the distortion measure may be available at the encoder, decoder, both, or neither. For example, such distortion side information can model reliabilities for noisy measurements, sensor calibration information, or perceptual effects like masking and sensitiv...
math
1,609
Shannon meets Wiener II: On MMSE estimation in successive decoding schemes
cs.IT
We continue to discuss why MMSE estimation arises in coding schemes that approach the capacity of linear Gaussian channels. Here we consider schemes that involve successive decoding, such as decision-feedback equalization or successive cancellation.
math
1,610
Capacity-achieving ensembles for the binary erasure channel with bounded complexity
cs.IT
We present two sequences of ensembles of non-systematic irregular repeat-accumulate codes which asymptotically (as their block length tends to infinity) achieve capacity on the binary erasure channel (BEC) with bounded complexity per information bit. This is in contrast to all previous constructions of capacity-achievi...
math
1,611
Bounds on the decoding complexity of punctured codes on graphs
cs.IT
We present two sequences of ensembles of non-systematic irregular repeat-accumulate codes which asymptotically (as their block length tends to infinity) achieve capacity on the binary erasure channel (BEC) with bounded complexity per information bit. This is in contrast to all previous constructions of capacity-achievi...
math
1,612
On the role of MMSE estimation in approaching the information-theoretic limits of linear Gaussian channels: Shannon meets Wiener
cs.IT
We discuss why MMSE estimation arises in lattice-based schemes for approaching the capacity of linear Gaussian channels, and comment on its properties.
math
1,613
Shannon Information and Kolmogorov Complexity
cs.IT
We compare the elementary theories of Shannon information and Kolmogorov complexity, the extent to which they have a common purpose, and where they are fundamentally different. We discuss and relate the basic notions of both theories: Shannon entropy versus Kolmogorov complexity, the relation of both to universal codin...
math
1,614
Capacity and Random-Coding Exponents for Channel Coding with Side Information
cs.IT
Capacity formulas and random-coding exponents are derived for a generalized family of Gel'fand-Pinsker coding problems. These exponents yield asymptotic upper bounds on the achievable log probability of error. In our model, information is to be reliably transmitted through a noisy channel with finite input and output a...
math
1,615
Source Coding with Fixed Lag Side Information
cs.IT
We consider source coding with fixed lag side information at the decoder. We focus on the special case of perfect side information with unit lag corresponding to source coding with feedforward (the dual of channel coding with feedback) introduced by Pradhan. We use this duality to develop a linear complexity algorithm ...
math
1,616
Two Methods for Decreasing the Computational Complexity of the MIMO ML Decoder
cs.IT
We propose use of QR factorization with sort and Dijkstra's algorithm for decreasing the computational complexity of the sphere decoder that is used for ML detection of signals on the multi-antenna fading channel. QR factorization with sort decreases the complexity of searching part of the decoder with small increase i...
math
1,617
Maximum Mutual Information of Space-Time Block Codes with Symbolwise Decodability
cs.IT
In this paper, we analyze the performance of space-time block codes which enable symbolwise maximum likelihood decoding. We derive an upper bound of maximum mutual information (MMI) on space-time block codes that enable symbolwise maximum likelihood decoding for a frequency non-selective quasi-static fading channel. MM...
math
1,618
Capacity Achieving Code Constructions for Two Classes of (d,k) Constraints
cs.IT
In this paper, we present two low complexity algorithms that achieve capacity for the noiseless (d,k) constrained channel when k=2d+1, or when k-d+1 is not prime. The first algorithm, called symbol sliding, is a generalized version of the bit flipping algorithm introduced by Aviran et al. [1]. In addition to achieving ...
math
1,619
Capacity Analysis for Continuous Alphabet Channels with Side Information, Part I: A General Framework
cs.IT
Capacity analysis for channels with side information at the receiver has been an active area of interest. This problem is well investigated for the case of finite alphabet channels. However, the results are not easily generalizable to the case of continuous alphabet channels due to analytic difficulties inherent with c...
math
1,620
Capacity Analysis for Continuous Alphabet Channels with Side Information, Part II: MIMO Channels
cs.IT
In this part, we consider the capacity analysis for wireless mobile systems with multiple antenna architectures. We apply the results of the first part to a commonly known baseband, discrete-time multiple antenna system where both the transmitter and receiver know the channel's statistical law. We analyze the capacity ...
math
1,621
Rate Distortion and Denoising of Individual Data Using Kolmogorov complexity
cs.IT
We examine the structure of families of distortion balls from the perspective of Kolmogorov complexity. Special attention is paid to the canonical rate-distortion function of a source word which returns the minimal Kolmogorov complexity of all distortion balls containing that word subject to a bound on their cardinalit...
math
1,622
Feedback Capacity of the First-Order Moving Average Gaussian Channel
cs.IT
The feedback capacity of the stationary Gaussian additive noise channel has been open, except for the case where the noise is white. Here we find the feedback capacity of the stationary first-order moving average additive Gaussian noise channel in closed form. Specifically, the channel is given by $Y_i = X_i + Z_i,$ $i...
math
1,623
Geographic Routing with Limited Information in Sensor Networks
cs.IT
Geographic routing with greedy relaying strategies have been widely studied as a routing scheme in sensor networks. These schemes assume that the nodes have perfect information about the location of the destination. When the distance between the source and destination is normalized to unity, the asymptotic routing dela...
math
1,624
On the High-SNR Capacity of Non-Coherent Networks
cs.IT
We obtain the first term in the high signal-to-noise ratio (SNR) expansion of the capacity of fading networks where the transmitters and receivers--while fully cognizant of the fading \emph{law}--have no access to the fading \emph{realization}. This term is an integer multiple of $\log \log \textnormal{SNR}$ with the c...
math
1,625
Monotonicity Results for Coherent MIMO Rician Channels
cs.IT
The dependence of the Gaussian input information rate on the line-of-sight (LOS) matrix in multiple-input multiple-output coherent Rician fading channels is explored. It is proved that the outage probability and the mutual information induced by a multivariate circularly symmetric Gaussian input with any covariance mat...
math
1,626
Complete Characterization of the Equivalent MIMO Channel for Quasi-Orthogonal Space-Time Codes
cs.IT
Recently, a quasi-orthogonal space-time block code (QSTBC) capable of achieving a significant fraction of the outage mutual information of a multiple-input-multiple output (MIMO) wireless communication system for the case of four transmit and one receive antennas was proposed. We generalize these results to $n_T=2^n$ t...
math
1,627
Mutual Information and Minimum Mean-square Error in Gaussian Channels
cs.IT
This paper deals with arbitrarily distributed finite-power input signals observed through an additive Gaussian noise channel. It shows a new formula that connects the input-output mutual information and the minimum mean-square error (MMSE) achievable by optimal estimation of the input given the output. That is, the der...
math
1,628
On the asymptotic accuracy of the union bound
cs.IT
A new lower bound on the error probability of maximum likelihood decoding of a binary code on a binary symmetric channel was proved in Barg and McGregor (2004, cs.IT/0407011). It was observed in that paper that this bound leads to a new region of code rates in which the random coding exponent is asymptotically tight, g...
math
1,629
Source Coding With Encoder Side Information
cs.IT
We introduce the idea of distortion side information, which does not directly depend on the source but instead affects the distortion measure. We show that such distortion side information is not only useful at the encoder, but that under certain conditions, knowing it at only the encoder is as good as knowing it at bo...
math
1,630
Source-Channel Diversity for Parallel Channels
cs.IT
We consider transmitting a source across a pair of independent, non-ergodic channels with random states (e.g., slow fading channels) so as to minimize the average distortion. The general problem is unsolved. Hence, we focus on comparing two commonly used source and channel encoding systems which correspond to exploitin...
math
1,631
A simple algorithm for decoding Reed-Solomon codes and its relation to the Welch-Berlekamp algorithm
cs.IT
A simple and natural Gao algorithm for decoding algebraic codes is described. Its relation to the Welch-Berlekamp and Euclidean algorithms is given.
math
1,632
Application of Generating Functions and Partial Differential Equations in Coding Theory
cs.IT
In this work we have considered formal power series and partial differential equations, and their relationship with Coding Theory. We have obtained the nature of solutions for the partial differential equations for Cycle Poisson Case. The coefficients for this case have been simulated, and the high tendency of growth i...
math
1,633
No-cloning principal can alone provide security
cs.IT
Existing quantum key distribution schemes need the support of classical authentication scheme to ensure security. This is a conceptual drawback of quantum cryptography. It is pointed out that quantum cryptosystem does not need any support of classical cryptosystem to ensure security. No-cloning principal can alone prov...
math
1,634
Thermodynamics of used punched tape: A weak and a strong equivalence principle
cs.IT
We study the repeated use of a monotonic recording medium--such as punched tape or photographic plate--where marks can be added at any time but never erased. (For practical purposes, also the electromagnetic "ether" falls into this class.) Our emphasis is on the case where the successive users act independently and sel...
math
1,635
Impact of Channel Estimation Errors on Multiuser Detection via the Replica Method
cs.IT
For practical wireless DS-CDMA systems, channel estimation is imperfect due to noise and interference. In this paper, the impact of channel estimation errors on multiuser detection (MUD) is analyzed under the framework of the replica method. System performance is obtained in the large system limit for optimal MUD, line...
math
1,636
Low Complexity Joint Iterative Equalization and Multiuser Detection in Dispersive DS-CDMA Channels
cs.IT
Communications in dispersive direct-sequence code-division multiple-access (DS-CDMA) channels suffer from intersymbol and multiple-access interference, which can significantly impair performance. Joint maximum \textit{a posteriori} probability (MAP) equalization and multiuser detection with error control decoding can b...
math
1,637
Performance Evaluation of Impulse Radio UWB Systems with Pulse-Based Polarity Randomization
cs.IT
In this paper, the performance of a binary phase shift keyed random time-hopping impulse radio system with pulse-based polarity randomization is analyzed. Transmission over frequency-selective channels is considered and the effects of inter-frame interference and multiple access interference on the performance of a gen...
math
1,638
Energy-Efficient Joint Estimation in Sensor Networks: Analog vs. Digital
cs.IT
Sensor networks in which energy is a limited resource so that energy consumption must be minimized for the intended application are considered. In this context, an energy-efficient method for the joint estimation of an unknown analog source under a given distortion constraint is proposed. The approach is purely analog,...
math
1,639
On the Capacity of Multiple Antenna Systems in Rician Fading
cs.IT
The effect of Rician-ness on the capacity of multiple antenna systems is investigated under the assumption that channel state information (CSI) is available only at the receiver. The average-power-constrained capacity of such systems is considered under two different assumptions on the knowledge about the fading availa...
math
1,640
A Large Deviations Approach to Sensor Scheduling for Detection of Correlated Random Fields
cs.IT
The problem of scheduling sensor transmissions for the detection of correlated random fields using spatially deployed sensors is considered. Using the large deviations principle, a closed-form expression for the error exponent of the miss probability is given as a function of the sensor spacing and signal-to-noise rati...
math
1,641
Concavity of the auxiliary function appearing in quantum reliability function an classical-quantum channels
cs.IT
Concavity of the auxiliary function which appears in the random coding exponent as the lower bound of the quantum reliability function for general quantum states is proven for s between 0 and 1.
math
1,642
Estimation of the Number of Sources in Unbalanced Arrays via Information Theoretic Criteria
cs.IT
Estimating the number of sources impinging on an array of sensors is a well known and well investigated problem. A common approach for solving this problem is to use an information theoretic criterion, such as Minimum Description Length (MDL) or the Akaike Information Criterion (AIC). The MDL estimator is known to be a...
math
1,643
Optimal and Suboptimal Finger Selection Algorithms for MMSE Rake Receivers in Impulse Radio Ultra-Wideband Systems
cs.IT
Convex relaxations of the optimal finger selection algorithm are proposed for a minimum mean square error (MMSE) Rake receiver in an impulse radio ultra-wideband system. First, the optimal finger selection problem is formulated as an integer programming problem with a non-convex objective function. Then, the objective ...
math
1,644
On The Tradeoff Between Two Types of Processing Gain
cs.IT
One of the features characterizing almost every multiple access (MA) communication system is the processing gain. Through the use of spreading sequences, the processing gain of Random CDMA systems (RCDMA), is devoted to both bandwidth expansion and orthogonalization of the signals transmitted by different users. Anothe...
math
1,645
A Non-Cooperative Power Control Game for Multi-Carrier CDMA Systems
cs.IT
In this work, a non-cooperative power control game for multi-carrier CDMA systems is proposed. In the proposed game, each user needs to decide how much power to transmit over each carrier to maximize its overall utility. The utility function considered here measures the number of reliable bits transmitted per joule of ...
math
1,646
The Noncoherent Rician Fading Channel -- Part I : Structure of the Capacity-Achieving Input
cs.IT
Transmission of information over a discrete-time memoryless Rician fading channel is considered where neither the receiver nor the transmitter knows the fading coefficients. First the structure of the capacity-achieving input signals is investigated when the input is constrained to have limited peakedness by imposing e...
math
1,647
The Noncoherent Rician Fading Channel -- Part II : Spectral Efficiency in the Low-Power Regime
cs.IT
Transmission of information over a discrete-time memoryless Rician fading channel is considered where neither the receiver nor the transmitter knows the fading coefficients. The spectral-efficiency/bit-energy tradeoff in the low-power regime is examined when the input has limited peakedness. It is shown that if a fourt...
math
1,648
Capacity Regions and Optimal Power Allocation for Groupwise Multiuser Detection
cs.IT
In this paper, optimal power allocation and capacity regions are derived for GSIC (groupwise successive interference cancellation) systems operating in multipath fading channels, under imperfect channel estimation conditions. It is shown that the impact of channel estimation errors on the system capacity is two-fold: i...
math
1,649
A Tree Search Method for Iterative Decoding of Underdetermined Multiuser Systems
cs.IT
Application of the turbo principle to multiuser decoding results in an exchange of probability distributions between two sets of constraints. Firstly, constraints imposed by the multiple-access channel, and secondly, individual constraints imposed by each users' error control code. A-posteriori probability computation ...
math
1,650
A Group-Theoretic Approach to the WSSUS Pulse Design Problem
cs.IT
We consider the pulse design problem in multicarrier transmission where the pulse shapes are adapted to the second order statistics of the WSSUS channel. Even though the problem has been addressed by many authors analytical insights are rather limited. First we show that the problem is equivalent to the pure state chan...
math
1,651
Space Frequency Codes from Spherical Codes
cs.IT
A new design method for high rate, fully diverse ('spherical') space frequency codes for MIMO-OFDM systems is proposed, which works for arbitrary numbers of antennas and subcarriers. The construction exploits a differential geometric connection between spherical codes and space time codes. The former are well studied e...
math
1,652
Information estimations and analysis of structures
cs.IT
In this paper have written the results of the information analysis of structures. The obtained information estimation (IE) are based on an entropy measure of C. Shannon. Obtained IE is univalent both for the non-isomorphic and for the isomorphic graphs, algorithmically, it is asymptotically steady and has vector charac...
math
1,653
Stochastic Iterative Decoders
cs.IT
This paper presents a stochastic algorithm for iterative error control decoding. We show that the stochastic decoding algorithm is an approximation of the sum-product algorithm. When the code's factor graph is a tree, as with trellises, the algorithm approaches maximum a-posteriori decoding. We also demonstrate a stoch...
math
1,654
A complexity-regularized quantization approach to nonlinear dimensionality reduction
cs.IT
We consider the problem of nonlinear dimensionality reduction: given a training set of high-dimensional data whose ``intrinsic'' low dimension is assumed known, find a feature extraction map to low-dimensional space, a reconstruction map back to high-dimensional space, and a geometric description of the dimension-reduc...
math
1,655
Some Extensions of Gallager's Method to General Sources and Channels
cs.IT
The Gallager bound is well known in the area of channel coding. However, most discussions about it mainly focus on its applications to memoryless channels. We show in this paper that the bounds obtained by Gallager's method are very tight even for general sources and channels that are defined in the information-spectru...
math
1,656
Idempotents, Mattson-Solomon Polynomials and Binary LDPC codes
cs.IT
We show how to construct an algorithm to search for binary idempotents which may be used to construct binary LDPC codes. The algorithm, which allows control of the key properties of sparseness, code rate and minimum distance, is constructed in the Mattson-Solomon domain. Some of the new codes, found by using this techn...
math
1,657
Pseudo-Codewords of Cycle Codes via Zeta Functions
cs.IT
Cycle codes are a special case of low-density parity-check (LDPC) codes and as such can be decoded using an iterative message-passing decoding algorithm on the associated Tanner graph. The existence of pseudo-codewords is known to cause the decoding algorithm to fail in certain instances. In this paper, we draw a conne...
math
1,658
Near Maximum-Likelihood Performance of Some New Cyclic Codes Constructed in the Finite-Field Transform Domain
cs.IT
It is shown that some well-known and some new cyclic codes with orthogonal parity-check equations can be constructed in the finite-field transform domain. It is also shown that, for some binary linear cyclic codes, the performance of the iterative decoder can be improved by substituting some of the dual code codewords ...
math
1,659
Improved Iterative Decoding for Perpendicular Magnetic Recording
cs.IT
An algorithm of improving the performance of iterative decoding on perpendicular magnetic recording is presented. This algorithm follows on the authors' previous works on the parallel and serial concatenated turbo codes and low-density parity-check codes. The application of this algorithm with signal-to-noise ratio mis...
math
1,660
GF(2^m) Low-Density Parity-Check Codes Derived from Cyclotomic Cosets
cs.IT
Based on the ideas of cyclotomic cosets, idempotents and Mattson-Solomon polynomials, we present a new method to construct GF(2^m), where m>0 cyclic low-density parity-check codes. The construction method produces the dual code idempotent which is used to define the parity-check matrix of the low-density parity-check c...
math
1,661
Unified Large System Analysis of MMSE and Adaptive Least Squares Receivers for a class of Random Matrix Channels
cs.IT
We present a unified large system analysis of linear receivers for a class of random matrix channels. The technique unifies the analysis of both the minimum-mean-squared-error (MMSE) receiver and the adaptive least-squares (ALS) receiver, and also uses a common approach for both random i.i.d. and random orthogonal prec...
math
1,662
Generalised Bent Criteria for Boolean Functions (I)
cs.IT
Generalisations of the bent property of a boolean function are presented, by proposing spectral analysis with respect to a well-chosen set of local unitary transforms. Quadratic boolean functions are related to simple graphs and it is shown that the orbit generated by successive Local Complementations on a graph can be...
math
1,663
Generalised Bent Criteria for Boolean Functions (II)
cs.IT
In the first part of this paper [16], some results on how to compute the flat spectra of Boolean constructions w.r.t. the transforms {I,H}^n, {H,N}^n and {I,H,N}^n were presented, and the relevance of Local Complementation to the quadratic case was indicated. In this second part, the results are applied to develop recu...
math
1,664
A low-cost time-hopping impulse radio system for high data rate transmission
cs.IT
We present an efficient, low-cost implementation of time-hopping impulse radio that fulfills the spectral mask mandated by the FCC and is suitable for high-data-rate, short-range communications. Key features are: (i) all-baseband implementation that obviates the need for passband components, (ii) symbol-rate (not chip ...
math
1,665
On quasi-cyclic interleavers for parallel turbo codes
cs.IT
We present an interleaving scheme that yields quasi-cyclic turbo codes. We prove that randomly chosen members of this family yield with probability almost 1 turbo codes with asymptotically optimum minimum distance, i.e. growing as a logarithm of the interleaver size. These interleavers are also very practical in terms ...
math
1,666
Nonlinear MMSE Multiuser Detection Based on Multivariate Gaussian Approximation
cs.IT
In this paper, a class of nonlinear MMSE multiuser detectors are derived based on a multivariate Gaussian approximation of the multiple access interference. This approach leads to expressions identical to those describing the probabilistic data association (PDA) detector, thus providing an alternative analytical justif...
math
1,667
Analysis of Second-order Statistics Based Semi-blind Channel Estimation in CDMA Channels
cs.IT
The performance of second order statistics (SOS) based semi-blind channel estimation in long-code DS-CDMA systems is analyzed. The covariance matrix of SOS estimates is obtained in the large system limit, and is used to analyze the large-sample performance of two SOS based semi-blind channel estimation algorithms. A no...
math
1,668
On the Achievable Information Rates of Finite-State Input Two-Dimensional Channels with Memory
cs.IT
The achievable information rate of finite-state input two-dimensional (2-D) channels with memory is an open problem, which is relevant, e.g., for inter-symbol-interference (ISI) channels and cellular multiple-access channels. We propose a method for simulation-based computation of such information rates. We first draw ...
math
1,669
Multilevel expander codes
cs.IT
We define multilevel codes on bipartite graphs that have properties analogous to multilevel serial concatenations. A decoding algorithm is described that corrects a proportion of errors equal to half the Blokh-Zyablov bound on the minimum distance. The error probability of this algorithm has exponent similar to that of...
math
1,670
Sensor Configuration and Activation for Field Detection in Large Sensor Arrays
cs.IT
The problems of sensor configuration and activation for the detection of correlated random fields using large sensor arrays are considered. Using results that characterize the large-array performance of sensor networks in this application, the detection capabilities of different sensor configurations are analyzed and c...
math
1,671
Impulse Radio Systems with Multiple Types of Ultra-Wideband Pulses
cs.IT
Spectral properties and performance of multi-pulse impulse radio ultra-wideband systems with pulse-based polarity randomization are analyzed. Instead of a single type of pulse transmitted in each frame, multiple types of pulses are considered, which is shown to reduce the effects of multiple-access interference. First,...
math
1,672
On the Typicality of the Linear Code Among the LDPC Coset Code Ensemble
cs.IT
Density evolution (DE) is one of the most powerful analytical tools for low-density parity-check (LDPC) codes on memoryless binary-input/symmetric-output channels. The case of non-symmetric channels is tackled either by the LDPC coset code ensemble (a channel symmetrizing argument) or by the generalized DE for linear c...
math
1,673
A New Non-Iterative Decoding Algorithm for the Erasure Channel : Comparisons with Enhanced Iterative Methods
cs.IT
This paper investigates decoding of binary linear block codes over the binary erasure channel (BEC). Of the current iterative decoding algorithms on this channel, we review the Recovery Algorithm and the Guess Algorithm. We then present a Multi-Guess Algorithm extended from the Guess Algorithm and a new algorithm -- th...
math
1,674
Duality Bounds on the Cut-Off Rate with Applications to Ricean Fading
cs.IT
We propose a technique to derive upper bounds on Gallager's cost-constrained random coding exponent function. Applying this technique to the non-coherent peak-power or average-power limited discrete time memoryless Ricean fading channel, we obtain the high signal-to-noise ratio (SNR) expansion of this channel's cut-off...
math
1,675
On a Kronecker products sum distance bounds
cs.IT
A binary linear error correcting codes represented by two code families Kronecker products sum are considered. The dimension and distance of new code is investigated. Upper and lower bounds of distance are obtained. Some examples are given. It is shown that some classic constructions are the private cases of considered...
math
1,676
Uplink Throughput in a Single-Macrocell/Single-Microcell CDMA System, with Application to Data Access Points
cs.IT
This paper studies a two-tier CDMA system in which the microcell base is converted into a data access point (DAP), i.e., a limited-range base station that provides high-speed access to one user at a time. The microcell (or DAP) user operates on the same frequency as the macrocell users and has the same chip rate. Howev...
math
1,677
Soft Handoff and Uplink Capacity in a Two-Tier CDMA System
cs.IT
This paper examines the effect of soft handoff on the uplink user capacity of a CDMA system consisting of a single macrocell in which a single hotspot microcell is embedded. The users of these two base stations operate over the same frequency band. In the soft handoff scenario studied here, both macrocell and microcell...
math
1,678
Uplink User Capacity in a CDMA System with Hotspot Microcells: Effects of Finite Transmit Power and Dispersion
cs.IT
This paper examines the uplink user capacity in a two-tier code division multiple access (CDMA) system with hotspot microcells when user terminal power is limited and the wireless channel is finitely-dispersive. A finitely-dispersive channel causes variable fading of the signal power at the output of the RAKE receiver....
math
1,679
On Multiflows in Random Unit-Disk Graphs, and the Capacity of Some Wireless Networks
cs.IT
We consider the capacity problem for wireless networks. Networks are modeled as random unit-disk graphs, and the capacity problem is formulated as one of finding the maximum value of a multicommodity flow. In this paper, we develop a proof technique based on which we are able to obtain a tight characterization of the s...
math
1,680
Randomly Spread CDMA: Asymptotics via Statistical Physics
cs.IT
This paper studies randomly spread code-division multiple access (CDMA) and multiuser detection in the large-system limit using the replica method developed in statistical physics. Arbitrary input distributions and flat fading are considered. A generic multiuser detector in the form of the posterior mean estimator is a...
math
1,681
Dynamic Shannon Coding
cs.IT
We present a new algorithm for dynamic prefix-free coding, based on Shannon coding. We give a simple analysis and prove a better upper bound on the length of the encoding produced than the corresponding bound for dynamic Huffman coding. We show how our algorithm can be modified for efficient length-restricted coding, a...
math
1,682
General non-asymptotic and asymptotic formulas in channel resolvability and identification capacity and their application to wire-tap channel
cs.IT
Several non-asymptotic formulas are established in channel resolvability and identification capacity, and they are applied to wire-tap channel. By using these formulas, the $\epsilon$ capacities of the above three problems are considered in the most general setting, where no structural assumptions such as the stationar...
math
1,683
Second order asymptotics in fixed-length source coding and intrinsic randomness
cs.IT
Second order asymptotics of fixed-length source coding and intrinsic randomness is discussed with a constant error constraint. There was a difference between optimal rates of fixed-length source coding and intrinsic randomness, which never occurred in the first order asymptotics. In addition, the relation between unifo...
math
1,684
Multiple Description Quantization via Gram-Schmidt Orthogonalization
cs.IT
The multiple description (MD) problem has received considerable attention as a model of information transmission over unreliable channels. A general framework for designing efficient multiple description quantization schemes is proposed in this paper. We provide a systematic treatment of the El Gamal-Cover (EGC) achiev...
math
1,685
Fast Codes for Large Alphabets
cs.IT
We address the problem of constructing a fast lossless code in the case when the source alphabet is large. The main idea of the new scheme may be described as follows. We group letters with small probabilities in subsets (acting as super letters) and use time consuming coding for these subsets only, whereas letters in ...
math
1,686
Using Information Theory Approach to Randomness Testing
cs.IT
We address the problem of detecting deviations of binary sequence from randomness,which is very important for random number (RNG) and pseudorandom number generators (PRNG). Namely, we consider a null hypothesis $H_0$ that a given bit sequence is generated by Bernoulli source with equal probabilities of 0 and 1 and the ...
math
1,687
Average Coset Weight Distribution of Combined LDPC Matrix Ensemble
cs.IT
In this paper, the average coset weight distribution (ACWD) of structured ensembles of LDPC (Low-density Parity-Check) matrix, which is called combined ensembles, is discussed. A combined ensemble is composed of a set of simpler ensembles such as a regular bipartite ensemble. Two classes of combined ensembles have prim...
math
1,688
Pseudocodewords of Tanner graphs
cs.IT
This papers presents a detailed analysis of pseudocodewords of Tanner graphs. Pseudocodewords arising on the iterative decoder's computation tree are distinguished from pseudocodewords arising on finite degree lifts. Lower bounds on the minimum pseudocodeword weight are presented for the BEC, BSC, and AWGN channel. Som...
math
1,689
Network Information Flow with Correlated Sources
cs.IT
In this paper, we consider a network communications problem in which multiple correlated sources must be delivered to a single data collector node, over a network of noisy independent point-to-point channels. We prove that perfect reconstruction of all the sources at the sink is possible if and only if, for all partiti...
math
1,690
Design of Block Transceivers with Decision Feedback Detection
cs.IT
This paper presents a method for jointly designing the transmitter-receiver pair in a block-by-block communication system that employs (intra-block) decision feedback detection. We provide closed-form expressions for transmitter-receiver pairs that simultaneously minimize the arithmetic mean squared error (MSE) at the ...
math
1,691
A new SISO algorithm with application to turbo equalization
cs.IT
In this paper we propose a new soft-input soft-output equalization algorithm, offering very good performance/complexity tradeoffs. It follows the structure of the BCJR algorithm, but dynamically constructs a simplified trellis during the forward recursion. In each trellis section, only the M states with the strongest f...
math
1,692
The Viterbi Algorithm: A Personal History
cs.IT
The story of the Viterbi algorithm (VA) is told from a personal perspective. Applications both within and beyond communications are discussed. In brief summary, the VA has proved to be an extremely important algorithm in a surprising variety of fields.
math
1,693
Near Perfect Decoding of LDPC Codes
cs.IT
Cooperative optimization is a new way for finding global optima of complicated functions of many variables. It has some important properties not possessed by any conventional optimization methods. It has been successfully applied in solving many large scale optimization problems in image processing, computer vision, an...
math
1,694
On Extrinsic Information of Good Codes Operating Over Discrete Memoryless Channels
cs.IT
We show that the Extrinsic Information about the coded bits of any good (capacity achieving) code operating over a wide class of discrete memoryless channels (DMC) is zero when channel capacity is below the code rate and positive constant otherwise, that is, the Extrinsic Information Transfer (EXIT) chart is a step fun...
math
1,695
Critical Point for Maximum Likelihood Decoding of Linear Block Codes
cs.IT
In this letter, the SNR value at which the error performance curve of a soft decision maximum likelihood decoder reaches the slope corresponding to the code minimum distance is determined for a random code. Based on this value, referred to as the critical point, new insight about soft bounded distance decoding of rando...
math
1,696
On the Entropy Rate of Pattern Processes
cs.IT
We study the entropy rate of pattern sequences of stochastic processes, and its relationship to the entropy rate of the original process. We give a complete characterization of this relationship for i.i.d. processes over arbitrary alphabets, stationary ergodic processes over discrete alphabets, and a broad family of st...
math
1,697
Bounds on the Entropy of Patterns of I.I.D. Sequences
cs.IT
Bounds on the entropy of patterns of sequences generated by independently identically distributed (i.i.d.) sources are derived. A pattern is a sequence of indices that contains all consecutive integer indices in increasing order of first occurrence. If the alphabet of a source that generated a sequence is unknown, the ...
math
1,698
Universal Minimax Discrete Denoising under Channel Uncertainty
cs.IT
The goal of a denoising algorithm is to recover a signal from its noise-corrupted observations. Perfect recovery is seldom possible and performance is measured under a given single-letter fidelity criterion. For discrete signals corrupted by a known discrete memoryless channel, the DUDE was recently shown to perform th...
math
1,699
Prediction of Large Alphabet Processes and Its Application to Adaptive Source Coding
cs.IT
The problem of predicting a sequence $x_1,x_2,...$ generated by a discrete source with unknown statistics is considered. Each letter $x_{t+1}$ is predicted using information on the word $x_1x_2... x_t$ only. In fact, this problem is a classical problem which has received much attention. Its history can be traced back t...
math