232 research outputs found
Exact-Regenerating Codes between MBR and MSR Points
In this paper we study distributed storage systems with exact repair. We give
a construction for regenerating codes between the minimum storage regenerating
(MSR) and the minimum bandwidth regenerating (MBR) points and show that in the
case that the parameters n, k, and d are close to each other our constructions
are close to optimal when comparing to the known capacity when only functional
repair is required. We do this by showing that when the distances of the
parameters n, k, and d are fixed but the actual values approach to infinity,
the fraction of the performance of our codes with exact repair and the known
capacity of codes with functional repair approaches to one.Comment: 5 pages, 2 figures, submitted to ITW 201
High-Rate Regenerating Codes Through Layering
In this paper, we provide explicit constructions for a class of exact-repair
regenerating codes that possess a layered structure. These regenerating codes
correspond to interior points on the storage-repair-bandwidth tradeoff, and
compare very well in comparison to scheme that employs space-sharing between
MSR and MBR codes. For the parameter set with , we
construct a class of codes with an auxiliary parameter , referred to as
canonical codes. With in the range , these codes operate in
the region between the MSR point and the MBR point, and perform significantly
better than the space-sharing line. They only require a field size greater than
. For the case of , canonical codes can also be shown to
achieve an interior point on the line-segment joining the MSR point and the
next point of slope-discontinuity on the storage-repair-bandwidth tradeoff.
Thus we establish the existence of exact-repair codes on a point other than the
MSR and the MBR point on the storage-repair-bandwidth tradeoff. We also
construct layered regenerating codes for general parameter set ,
which we refer to as non-canonical codes. These codes also perform
significantly better than the space-sharing line, though they require a
significantly higher field size. All the codes constructed in this paper are
high-rate, can repair multiple node-failures and do not require any computation
at the helper nodes. We also construct optimal codes with locality in which the
local codes are layered regenerating codes.Comment: 20 pages, 9 figure
New Codes and Inner Bounds for Exact Repair in Distributed Storage Systems
We study the exact-repair tradeoff between storage and repair bandwidth in
distributed storage systems (DSS). We give new inner bounds for the tradeoff
region and provide code constructions that achieve these bounds.Comment: Submitted to the IEEE International Symposium on Information Theory
(ISIT) 2014. This draft contains 8 pages and 4 figure
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