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This correspondence introduces a framework to design and analyze low-density parity-check (LDPC) codes over nonuniform channels. We study LDPC codes for channels with nonuniform noise distributions, rate-adaptive coding, and unequal error protection. First, we propose a technique to design LDPC codes for volume holographic memory (VHM) systems for which the(More)
This paper investigates decoding of low-density parity-check (LDPC) codes over the binary erasure channel (BEC). We study the iterative and maximum-likelihood (ML) decoding of LDPC codes on this channel. We derive bounds on the ML decoding of LDPC codes on the BEC. We then present an improved decoding algorithm. The proposed algorithm has almost the same(More)
This paper first introduces an improved decoding algorithm for low-density parity-check (LDPC) codes over binary-input-output-symmetric memoryless channels. Then some fundamental properties of punctured LDPC codes are presented. It is proved that for any ensemble of LDPC codes, there exists a puncturing threshold. It is then proved that for any rates(More)
—In this paper, we propose a scheme to construct low-density parity-check (LDPC) codes that are suitable for unequal error protection (UEP). We derive density evolution (DE) formulas for the proposed unequal error protecting LDPC ensembles over the binary erasure channel (BEC). Using the DE formulas, we optimize the codes. For the finite-length cases, we(More)
—This paper initiates the study of scaling laws for vehicular ad hoc networks (VANET)s. It provides a general framework to study VANETs. The fundamental capacity limits of these networks are investigated and we show how the road geometry affects this capacity. The VANET capacity is calculated for different road structures. The need for new capacity metrics(More)
With the objective of minimizing the total cost, which includes both sensor and congestion costs, the authors adopted a novel sampling theorem approach to address the problem of sensor spacing optimization. This paper presents the analysis and modeling of the power spectral density of traffic information as a 2-D stochastic signal using highly detailed(More)
spatially coupled Low-Density Parity-Check (LDPC) codes, non-binary LDPC codes, and any channel and hence generalise the concept of error correction to general codes can be decoded in a continuous fashion using a sliding window de-ing, non-uniform window decoding schedules has been introduced. First, twenty four original Low-Density Parity Check (LDPC)(More)
—The effectiveness and straightforward implementation of physical layer jammers make them an essential security threat for wireless networks. In this paper, reliable communication in a wireless multi-hop network in the presence of multiple malicious jammers is considered. Since energy consumption is an important issue in wireless ad hoc networks, minimum(More)
—A universal communications scheme for Vehicular Ad hoc Networks (VANETs) is proposed. This scheme accounts for a diverse variety of VANET-specific characteristics such as the gradual introduction of technology, highly dynamic topology, road-constrained vehicle movement and the presence of obstacles. The scheme incorporates a geometrical framework(More)