15 research outputs found
Projective codes meeting the Griesmer bound
AbstractWe present a brief survey of projective codes meeting the Griesmer bound. Methods for constructing large families of codes as well as sporadic codes meeting the bound are given. Current research on the classification of codes meeting the Griesmer bound is also presented
Update-Efficiency and Local Repairability Limits for Capacity Approaching Codes
Motivated by distributed storage applications, we investigate the degree to
which capacity achieving encodings can be efficiently updated when a single
information bit changes, and the degree to which such encodings can be
efficiently (i.e., locally) repaired when single encoded bit is lost.
Specifically, we first develop conditions under which optimum
error-correction and update-efficiency are possible, and establish that the
number of encoded bits that must change in response to a change in a single
information bit must scale logarithmically in the block-length of the code if
we are to achieve any nontrivial rate with vanishing probability of error over
the binary erasure or binary symmetric channels. Moreover, we show there exist
capacity-achieving codes with this scaling.
With respect to local repairability, we develop tight upper and lower bounds
on the number of remaining encoded bits that are needed to recover a single
lost bit of the encoding. In particular, we show that if the code-rate is
less than the capacity, then for optimal codes, the maximum number
of codeword symbols required to recover one lost symbol must scale as
.
Several variations on---and extensions of---these results are also developed.Comment: Accepted to appear in JSA
Entanglement-Assisted Quantum Communication Beating the Quantum Singleton Bound
Brun, Devetak, and Hsieh [Science 314, 436 (2006)] demonstrated that
pre-shared entanglement between sender and receiver enables quantum
communication protocols that have better parameters than schemes without the
assistance of entanglement. Subsequently, the same authors derived a version of
the so-called quantum Singleton bound that relates the parameters of the
entanglement-assisted quantum-error correcting codes proposed by them. We
present a new entanglement-assisted quantum communication scheme with
parameters violating this bound in certain ranges
The weight enumerator polynomials of the lifted codes of the projective Solomon-Stiffler codes
Determining the weight distribution of a code is an old and fundamental topic
in coding theory that has been thoroughly studied. In 1977, Helleseth,
Kl{\o}ve, and Mykkeltveit presented a weight enumerator polynomial of the
lifted code over of a -ary linear code with
significant combinatorial properties, which can determine the support weight
distribution of this linear code. The Solomon-Stiffler codes are a family of
famous Griesmer codes, which were proposed by Solomon and Stiffler in 1965. In
this paper, we determine the weight enumerator polynomials of the lifted codes
of the projective Solomon-Stiffler codes using some combinatorial properties of
subspaces. As a result, we determine the support weight distributions of the
projective Solomon-Stiffler codes. In particular, we determine the weight
hierarchies of the projective Solomon-Stiffler codes.Comment: This manuscript was first submitted on September 9, 202
Covering Radius 1985-1994
We survey important developments in the theory of covering radius during the period 1985-1994. We present lower bounds, constructions and upper bounds, the linear and nonlinear cases, density and asymptotic results, normality, specific classes of codes, covering radius and dual distance, tables, and open problems
Publications of the Jet Propulsion Laboratory, July 1964 through June 1965
JPL publications bibliography with abstracts - reports on DSIF, Mariner program, Ranger project, Surveyor project, and other space programs, and space science