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Although error-prone patterns have been extensively studied for low-density parity-check (LDPC) codes, to the best of our knowledge, they have never been fully explored for Fountain codes. It is shown that dominant trapping sets of Fountain codes are the absorbing sets. They happen in the so-called error floor, corresponding to a significant flattening in the error probability curves. In this paper,...
Flash Analog-to-Digital Converters (ADCs) are usually used in high-speed yet low-resolution applications such as wideband radio transceivers. Since the power consumption of such ADCs exponentially rises with the number of bits, low-power design techniques are of increasing interest. In this work, the power consumption of the comparators, the most important building blocks in such ADCs, have been reduced...
A novel method to combine encryption and channel coding in such a way as to get increased security without any additional complexity is presented in this paper. A secure communication system usually consists of an encryption block followed by the channel coder. The encryption block here is a Shrinking generator which is a Linear Feedback Shift Register (LFSR) based stream cipher system. The channel...
Cooperation among nodes is proposed as an effective means of combating fading and for enhancing system's overall capacity and coverage. The robustness of rateless codes makes them particularly attractive for such networks. Yet, the decoding aspects of rateless codes are discarded in most of the traditional distributed networks. In this paper, the intermediate packet decodability of rateless codes...
Technology scaling introduces many sources of variability and uncertainty that are difficult to model and predict [3]. The result of these uncertainties is a degradation in our ability to predict the performance of fabricated chips, i.e., a lack of model-to-hardware matching. The prediction of circuit performance is the result of a complex hierarchy of models starting at the basic MOSFET device model...
Due to the use of commodity software and hardware, crash-stop and Byzantine failures are likely to be more prevalent in today's large-scale distributed storage systems. Regenerating codes have been shown to be a more efficient way to disperse information across multiple nodes and recover crash-stop failures in the literature. In this paper, we present the design of regeneration codes in conjunction...
This paper describes the implementation of a fast information encoder and decoder for UHF radio considering the trade-off of speed of operation and storage space. (24, 12, 8) Golay code was implemented on an 8051 core based 8-bit microcontroller with a speed of around 60MHz. The different available techniques to encode and decode Golay codes are discussed. A comparative study of the implementation...
In this paper, we present an error-trellis construction for tailbiting convolutional codes. A tailbiting error-trellis is characterized by the condition that the syndrome former starts and ends in the same state. We clarify the correspondence between code subtrellises in the tailbiting code-trellis and error subtrellises in the tailbiting error-trellis. Also, we obtain the scalar parity-check matrix...
We consider two methods that construct high rate punctured convolutional codes. First, we present best high rate R = (n−1)/n punctured convolutional codes, for n = 5,6, · · ·, 16, which are found by exhaustive searches. To obtain the best code, we use a regular convolutional code whose weight spectrum is equivalent to that of each punctured convolutional code. We search these regular equivalent codes...
In this paper, we present a customizable online application development environment and an online marketplace system. We applied development resource virtualization technology in order to support multiple developers who create application with an each customized development environment.
The work presented in this paper focuses on an efficient erasure-only decoding algorithm for Generalized Reed-Solomon (in short, GRS) codes. The underlying principle of previous decoding algorithms for GRS is first to recover the codewords and further to obtain the original messages. Greatly different from the previous solutions, our novel algorithm, referred to as Direct Erasure-only Decoding, can...
We investigate the error floor performance of Luby Transform (LT) codes over the additive white Gaussian noise channel. We first derive a lower bound on the bit error rate for an LT code, which we subsequently use to show that the corresponding error floor is predominantly caused by low-degree variable nodes. Based on this observation, we propose a modified encoding scheme for LT codes that provides...
As the feature sizes of integrated circuits decreasing, single event transient (SET) in combinational circuits can not been ignored any longer. In this paper, a novel fault-secure scheme for memory has been proposed by studying the structural features of Euclidean Geometry-Low Density Parity Check (EG-LDPC) codes. The proposed fault-secure scheme can tolerate transient faults both in the storage cell...
In this work, network coding is employed to obtain maximum diversity order in a network where the users have independent information to transmit to a common base station. We elaborate on the recently proposed generalized dynamic network codes (GDNC), which can only achieve part of the maximum diversity order when the inter-user channels are subject to outages. In particular, by allowing the users...
Quadratic permutation polynomial (QPP) interleaver is a contention-free interleaver which is suitable for parallel turbo decoder implementation. In this paper, a systematic recursive method to design configurable QPP interleaving multistage network is proposed based on the property of QPP. Due to the nature of recursion, the proposed network for 2n-level parallel turbo decoder can be used for any...
It was recently shown that spatial coupling of individual low-density parity-check codes improves the belief-propagation threshold of the coupled ensemble essentially to the maximum a posteriori threshold of the underlying ensemble. We study the performance of spatially coupled low-density generator-matrix ensembles when used for transmission over binary-input memoryless output-symmetric channels...
This paper presents a tree-based algebraic construction of nested cyclic codes through a tree construction method. These codes can be used to encode different data packets, producing codewords that are added for transmission. Both encoding and decoding are performed by polynomial operations with no need of side information, so the proposed scheme may be useful in applications that require low computational...
The Goppa Code Distinguishing (GCD) problem consists in distinguishing the matrix of a Goppa code from a random matrix. Up to now, it is widely believed that the GCD problem is a hard decisional problem. We present the first technique allowing to distinguish alternant and Goppa codes over any field. Our technique can solve the GCD problem in polynomial-time provided that the codes have rates sufficiently...
Q-ary lattices can be obtained from q-ary codes using the so-called Construction A. We investigate these lattices in the Lee metric and show how their decoding process can be related to the associated codes. For prime q we derive a Lee sphere decoding algorithm for q-ary lattices, present a brief discussion on its complexity and some comparisons with the classic sphere decoding.
MDS erasure codes are ubiquitous in storage systems that must tolerate failures. While classic Reed-Solomon codes can provide a general-purpose MDS code for any situation, systems that require high performance rely on special-purpose codes that employ the bitwise exclusive-or (XOR) operation, and may be expressed in terms of a binary generator matrix. There are known lower bounds on the density of...
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