IEEE Transactions on Information Theory

Trellis coding using multidimensional quadrature amplitude modulation (QAM) signal sets is investigated. Finite-size 2D signal sets are presented that have minimum average energy, are 90 degrees rotationally symmetric, and have from 16 to 1024 points. The best trellis codes using the finite 16-QAM signal set with two, four, six, and eight dimensions are found by computer search (the multidimension... View full abstract»

Various aspects of single-phased burst-error-correcting array codes are explored. These codes are composed of two-dimensional arrays with row and column parities with a diagonally cyclic readout order; they are capable of correcting a single burst error along one diagonal. Optimal codeword sizes are found to have dimensions n1 ×n2 such that n<... View full abstract»

An algorithm that, for codes from a regular plane curve, corrects up to (d*/2)-(m²/8)+(m/4)-(9/8) errors, where d* is the designed distance and m is the degree of the curve, was presented in an earlier work (see ibid., vol.35, p.811-21, 1989). It is now shown that this bound is the best possible for the algorithm considered View full abstract»

Numerical computer data in many applications contain numerous leading and trailing zeros, and this data feature has been neglected in common source models and related data compression methods. A new approach to source modeling, consisting of the description of this data feature by probabilities pij of data values with i leading and j trailing zeros, is propose... View full abstract»

Combining Delsarte's (1973) linear programming bound with the information that certain weights cannot occur, new upper bounds for d_min (n,k), the maximum possible minimum distance of a binary linear code with given word length n and dimension k, are derived View full abstract»

A communication channel consisting of several subchannels transmitting simultaneously and asynchronously is considered, an example being a board with several chips, where the subchannels are wires connecting the chips and differences in the lengths of the wires can result in asynchronous reception. A scheme that allows transmission without an acknowledgment of the message, therefore permitting pip... View full abstract»

Tables with lower and upper bounds for d_max ( n,k), the maximum possible minimum distance of a binary linear code with word length n and dimension k, are shown View full abstract»

A family of queues is studied for which the service time Bn of customer n and the interarrival time In between customers n-1 and n exhibit some sort of proportionality. The focus is on dependencies that arise naturally in the context of communication systems, where the finite speed of the communication links constrains the amount o... View full abstract»

A class of random time-series inputs for nonlinear time-invariant systems that permit the analytical specification of a set of operators on the input that are orthonormal over all time to the Volterra operators for all orders and all lag sets is introduced. The time series in this class are cyclostationary and complex valued. The orthonormal operators are used to obtain an input-output type of cro... View full abstract»

Let R(r,m) be the rth-order Reed-Muller code of length 2m and let ρ(r,m ) be its covering radius. R(2,7), R(2,8), R (3,7), and R(4,8) are among those smallest Reed-Muller codes whose covering radii are not known. New bounds for the covering radii of these four codes are obtained. The results ar... View full abstract»

Difference bases are discussed and their relevance to sensor arrays is described. Several new analytical difference base structures that result in near optimal low-redundancy sensor arrays are introduced. Algorithms are also presented for efficiently obtaining sparse sensor arrays and/or difference bases. New bounds, related to arrays that have both redundancies and holes in their coarray, are pre... View full abstract»

Simple statistical hypothesis testing is investigated by making use of the divergence geometric method. The asymptotic behavior of the minimum value of the error probability of the second kind under the constraint that the error probability of the first kind is bounded above by exp(-rn) is looked for, where r is a given positive number. If r is greater than the divergenc... View full abstract»

Codes for the multibit peak-shift recording channel, called (d ,k)-codes of reduced length N, are considered. Arbitrary (d,k)- and perfect (d,k)-codes capable of correcting single peak-shifts of given size t are defined. For the construction of perfect codes, a general combinatorial method connected with finding `good' weight ... View full abstract»

Distributed algorithms for finding two disjoint paths of minimum total length from each node to a destination are presented. The algorithms have both node-disjoint and link-disjoint versions and provide each node with information sufficient to forward data on the disjoint paths. It is shown that this problem can be reduced to the problem of finding a minimal shortest path from each node to the des... View full abstract»

Some relations between the minimum support weights are discussed. In particular, the possible weight hierarchies of codes of dimension 4 are determined View full abstract»

There are two approaches to the identification of noncausal autoregressive systems in two dimensions differing in the assumed noise model. For both approaches, the maximum likelihood estimator formulated in the frequency domain is presented. The Fisher information matrix is evaluated and found to be the sum of a block-Toeplitz and a block-Hankel matrix. The variance of the parameters, however, can... View full abstract»

A coded automatic repeat request (ARQ) scheme based on a generalized Viterbi decoding algorithm is proposed. The scheme utilizes the error propagation, which is commonly observed in reduced-complexity decoding, as a means of error detection. It is shown that a small undetectable error probability is obtained with a small retransmission probability for a discrete memoryless channel, contrary to the... View full abstract»

A Reed-Solomon code decoding algorithm based on Newton's interpolation is presented. This algorithm has as main application fast generalized-minimum-distance decoding of Reed-Solomon codes. It uses a modified Berlekamp-Massey algorithm to perform all necessary generalized-minimum-distance decoding steps in only one run. With a time-domain form of the new decoder the overall asymptotic generalized-... View full abstract»

BCH decoders based on the Peterson-Gorenstein-Zierler algorithm can malfunction and produce output vectors that are no codewords. To avoid this malfunction a simple additional check is proposed that can be performed before the computation of the error locations. The additional check consists of the minimum number of algebraic equations in the syndrome components that are necessary over a general f... View full abstract»

The asymptotic efficiency of importance sampling (IS) techniques for the simulation of rare events in a multidimensional nonlinear setting was studied by J.S. Sadowsky and J.A. Bucklew (see ibid., vol.36, p.579-88, 1990). Fundamental results on the asymptotic efficiency of the mean-value modification (MM) technique were derived. Additionally, a statement was made that other IS techniques cannot be... View full abstract»

A class of iterative methods for solving the blind deconvolution problem, i.e. for recovering the input of an unknown possibly nonminimum-phase linear system by observation of its output, is presented. These methods are universal do not require prior knowledge of the input distribution, are computationally efficient and statistically stable, and converge to the desired solution regardless of initi... View full abstract»

A new approach toward robust parameter estimation is presented. As opposed to schemes based on classical saddlepoint techniques, the methods apply quite naturally to dependent and/or nonstationary data and also have the advantage of providing a quantitative measure of the degree of robustness offered by a particular estimator. It is shown why censoring observations of large magnitude does indeed i... View full abstract»

The basic algorithm for decoding of algebraic-geometric codes corrects up to (dc-1)2-g/2 errors, where d c denotes the designed minimum distance of a code and g denotes the genus of a curve. The modified algorithm improves on this, but applies to a restricted class of codes. An extended modified algorithm that applies to all codes is formulated. It... View full abstract»

Deterministic prediction in progressive coding of images is investigated. Progressive coding first creates a sequence of resolution layers by beginning with an original image and reducing its resolution several times by factors of some natural number M. The resultant layers are losslessly encoded, beginning with the lowest-resolution layer and, then encoding each higher resolution image i... View full abstract»

Consider N parallel queues competing for the attention of a single server. At each time slot each queue may be connected to the server or not depending on the value of a binary random variable, the connectivity variable. Allocation at each slot; is based on the connectivity information and on the lengths of the connected queues only. At the end of each slot, service may be completed with ... View full abstract»