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The following topics are dealt with: MAC polar codes; quasi-cyclic LDPC codes; channel capacity; network coding delay; underwater acoustic signal detection; speech recognition; speech coding; convolutional codes; cooperative MIMO channels; CSMA scheduling; asymptotic outage analysis of ad hoc networks; secrecy capacity scaling in wireless networks; iterative decoding of cyclic codes; optimal buffer...
We study error-correcting codes for permutations under the infinity norm, motivated the rank-modulation scheme for flash memories. In this scheme, a set of n flash cells are combined to create a single virtual multi-level cell. Information is stored in the permutation induced by the cell charge levels. Spike errors, which are characterized by a limited-magnitude change in cell charge levels, correspond...
By focusing on a class of source coding schemes built around entropy coded dithered quantizers, we develop a framework to deal with average data-rate constraints in a tractable manner that combines ideas from both information and control theories. We focus on a situation where a noisy linear system has been designed assuming transparent feedback and, due to implementation constraints, a source coding...
Screening for carriers of rare variants by resequencing is important for the identification of individuals carrying disease alleles. Rapid sequencing by new technologies enables low-cost resequencing of target regions, although it is still prohibitive to test more than a few individuals. Pooling designs can enable detection of carriers of rare alleles in groups of individuals in a more economical...
In many known examples where compress-and-forward (CF) for relay networks is capacity achieving, it is only trivially so, i.e., it falls back to hashing without quantization. A potentially better strategy is to decode as much as possible and to compress the residual information, i.e., a combination of decode-and-forward (DF) and CF (Cover and El Gamal's Theorem 7). Indeed such a strategy was shown...
We study a random extended network, where the legitimate and eavesdropper nodes are assumed to be placed according to Poisson point processes in a square region of area n. It is shown that, when the legitimate nodes have unit intensity, ?? = 1, and the eavesdroppers have an intensity of ??e = O((log n)-2), almost all of the nodes achieve a perfectly secure rate of ?? (1/??n). The achievability argument...
We introduce a distributed stateless MAC protocol referred to as Random Capture Algorithm (RCA) and analyze its performance in networks where interference is modeled by a contention graph. RCA does not require any message passing, nor transmitters to be aware of the content of their respective buffers. Yet, it achieves at least the same stability region as that obtained with maximal scheduling. We...
The paper proposes a factor graph representation of finite-dimensional continuous-time linear systems /filters driven by white Gaussian noise. Applications of such factor graphs include (i) simulation of the output signal at arbitrary discrete instants and (ii) MAP /MMSE /LMMSE estimation of the input signal, or of the state, or of the output signal at arbitrary discrete instants from noisy observations...
In the distributed storage coding problem we consider, data is stored across n nodes in a network, each capable of storing ?? symbols. It is required that the complete data can be reconstructed by downloading data from any k nodes. There is also the key additional requirement that a failed node be regenerated by connecting to any d nodes and downloading ?? symbols from each of them. Our goal is to...
In this paper, a method is presented for enumerating the trapping sets of a specific LDPC code given its Tanner graph. The technique involves augmenting the original Tanner graph with additional variable nodes, and then applying a weight-enumeration algorithm to the augmented Tanner graph. The proposed method is used to find trapping set enumerators for several LDPC codes in communication standards...
The energy-distortion tradeoff for lossy transmission of sources over multi-user networks is studied. The energy-distortion function E(D) is defined as the minimum energy required to transmit a source to the receiver within the target distortion D, when there is no restriction on the number of channel uses per source sample. For point-to-point channels, E(D) is shown to be equal to the product of...
In this paper, we derive a single-letter expression for the capacity of the finite-state channel (FSC) with delayed output and state feedback by formulating the problem in a stochastic control framework. The resulting capacity expression can be evaluated using dynamic programming. Although the considered channel is a special case of the one investigated by Tatikonda and Mitter, our approach is somewhat...
This paper investigates the sum-rate capacity of a multi-user broadcast channel (BC) assuming that users have different transmit correlation matrices. The sum-rate capacity of two-user BC has recently been investigated. As an extension of the two-user BC case, we analyze the sum-rate capacity of a multi-user BC. It is shown by means of upper-bound analysis that the sum-rate capacity of a correlated...
Phoneme classification is investigated in linear feature domains with the aim of improving the robustness to additive noise. Linear feature domains allow for exact noise adaptation and so should result in more accurate classification than representations involving nonlinear processing and dimensionality reduction. We develop a generative framework for phoneme classification using linear features....
In contrast to the capacity approaching performance of iteratively decoded low-density parity check (LDPC) codes, many practical finite-length LDPC codes exhibit performance degradation, manifested in a so-called error floor. Previous work has linked this phenomenon to the presence of certain combinatorial structures within the Tanner graph representation of the code, termed absorbing sets. Absorbing...
In this paper, we propose a new path metric, which improves the performance of soft-input soft-output (SISO) tree detection for iterative detection and decoding (IDD) systems. While the conventional path metric accounts for the contribution of symbols on a visited path due to the causal nature of tree search, the new path metric, called improved path metric, reflect the contribution of unvisited paths...
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