Erasure codes, such as Reed-Solomon (RS) codes, are being increasingly employed in data centers to combat the cost of reliably storing large amounts of data. Although these codes provide optimal storage efficiency, they require significantly high network and disk usage during recovery of missing data. In this paper, we first present a study on the impact of recovery operations of erasure-coded ...

With increase in scale, the number of node failures in a data center increases sharply. To ensure availability of data, failure-tolerance schemes such as ReedSolomon (RS) or more generally, Maximum Distance Separable (MDS) erasure codes are used. However, while MDS codes offer minimum storage overhead for a given amount of failure tolerance, they do not meet other practical needs of today’s dat...

In this paper, we investigate the impact of spatial coupling on the thresholds of turbo-like codes. Parallel concatenated and serially concatenated convolutional codes as well as braided convolutional codes (BCCs) are compared by means of an exact density evolution (DE) analysis for the binary erasure channel (BEC). We propose two extensions of the original BCC ensemble to improve its threshold...

Maximum distance profile (MDP) convolutional codes have the property that their column distances are as large as possible. It has been shown that, transmitting over an erasure channel, these codes have optimal recovery rate for windows of a certain length. Reverse MDP convolutional codes have the additional advantage that they are suitable for forward and backward decoding algorithms. Beyond th...

Cooperative computation is a promising approach for localized data processing for Internet of Things (IoT), where computationally intensive tasks in a device could be divided into sub-tasks, and offloaded to other devices or servers in close proximity. However, exploiting the potential of cooperative computation is challenging mainly due to the heterogeneous nature of IoT devices. Indeed, IoT d...

In peer-to-peer storage systems, peers can freely join and leave the system at any time. Ensuring high data availability in such an environment is a challenging task. In this paper we analyze the costs of achieving data availability in fully decentralized peer-to-peer systems. We mainly address the problem of churn and what effect maintaining availability has on network bandwidth. We discuss tw...

In this paper we address the reliability problem in storage-centric sensor networks deployed in hazardous environments. We use the nodes’ extra flash memory to save distributed encoded blocks of data. We employ erasure coding to substantially improve the trade-off between storage reliability and required disk capacity. Moreover, efficient mechanisms are designed for spreading the encoded pieces...

We derive the density evolution equations for non-binary low-density parity-check (LDPC) ensembles when transmission takes place over the binary erasure channel. We introduce ensembles defined with respect to the general linear group over the binary field. For these ensembles the density evolution equations can be written compactly. The density evolution for the general linear group helps us in...

This paper considers the queueing performance of a system that transmits coded data over a time-varying erasure channel. In our model, the queue length and channel state together form a Markov chain that depends on the system parameters. This gives a framework that allows a rigorous analysis of the queue as a function of the code rate. Most prior work in this area either ignores block-length (e...

Unequal error protection (UEP) codes provide a selective level of protection for different blocks of the information message. The effectiveness of two sub-optimum soft-decision decoding algorithms, namely generalized Chase-2 and weighted erasure decoding, is evaluated in this study for each protection class of UEP block codes. The performances of both algorithms are compared to that of the maxi...