113 research outputs found
On the Hamming Auto- and Cross-correlation Functions of a Class of Frequency Hopping Sequences of Length
In this paper, a new class of frequency hopping sequences (FHSs) of length is constructed by using Ding-Helleseth generalized cyclotomic classes
of order 2, of which the Hamming auto- and cross-correlation functions are
investigated (for the Hamming cross-correlation, only the case is considered). It is shown that the set of the constructed FHSs is optimal
with respect to the average Hamming correlation functions
Construction of three classes of Strictly Optimal Frequency-Hopping Sequence Sets
In this paper, we construct three classes of strictly optimal
frequency-hopping sequence (FHS) sets with respect to partial Hamming
correlation and family size. The first class is based on a generic
construction, the second and third classes are based from the trace map
Three new classes of optimal frequency-hopping sequence sets
The study of frequency-hopping sequences (FHSs) has been focused on the
establishment of theoretical bounds for the parameters of FHSs as well as on
the construction of optimal FHSs with respect to the bounds. Peng and Fan
(2004) derived two lower bounds on the maximum nontrivial Hamming correlation
of an FHS set, which is an important indicator in measuring the performance of
an FHS set employed in practice.
In this paper, we obtain two main results. We study the construction of new
optimal frequency-hopping sequence sets by using cyclic codes over finite
fields. Let be a cyclic code of length over a finite field
such that contains the one-dimensional subcode Two codewords of are said to be equivalent if
one can be obtained from the other through applying the cyclic shift a certain
number of times. We present a necessary and sufficient condition under which
the equivalence class of any codeword in
has size . This result addresses an open question raised by Ding {\it et
al.} in \cite{Ding09}. As a consequence, three new classes of optimal FHS sets
with respect to the Singleton bound are obtained, some of which are also
optimal with respect to the Peng-Fan bound at the same time. We also show that
the two Peng-Fan bounds are, in fact, identical.Comment: to appear in Designs, Codes and Cryptograph
Asymptotic Gilbert-Varshamov bound on Frequency Hopping Sequences
Given a -ary frequency hopping sequence set of length and size
with Hamming correlation , one can obtain a -ary (nonlinear) cyclic code
of length and size with Hamming distance . Thus, every upper
bound on the size of a code from coding theory gives an upper bound on the size
of a frequency hopping sequence set. Indeed, all upper bounds from coding
theory have been converted to upper bounds on frequency hopping sequence sets
(\cite{Ding09}). On the other hand, a lower bound from coding theory does not
automatically produce a lower bound for frequency hopping sequence sets. In
particular, the most important lower bound--the Gilbert-Varshamov bound in
coding theory has not been transformed to frequency hopping sequence sets. The
purpose of this paper is to convert the Gilbert-Varshamov bound in coding
theory to frequency hopping sequence sets by establishing a connection between
a special family of cyclic codes (which are called hopping cyclic codes in this
paper) and frequency hopping sequence sets. We provide two proofs of the
Gilbert-Varshamov bound. One is based on probabilistic method that requires
advanced tool--martingale. This proof covers the whole rate region. The other
proof is purely elementary but only covers part of the rate region
New families of optimal frequency hopping sequence sets
Frequency hopping sequences (FHSs) are employed to mitigate the interferences
caused by the hits of frequencies in frequency hopping spread spectrum systems.
In this paper, we present some new algebraic and combinatorial constructions
for FHS sets, including an algebraic construction via the linear mapping, two
direct constructions by using cyclotomic classes and recursive constructions
based on cyclic difference matrices. By these constructions, a number of series
of new FHS sets are then produced. These FHS sets are optimal with respect to
the Peng-Fan bounds.Comment: 10 page
Construction of Frequency Hopping Sequence Set Based upon Generalized Cyclotomy
Frequency hopping (FH) sequences play a key role in frequency hopping spread
spectrum communication systems. It is important to find FH sequences which have
simultaneously good Hamming correlation, large family size and large period. In
this paper, a new set of FH sequences with large period is proposed, and the
Hamming correlation distribution of the new set is investigated. The
construction of new FH sequences is based upon Whiteman's generalized
cyclotomy. It is shown that the proposed FH sequence set is optimal with
respect to the average Hamming correlation bound.Comment: 16 page
A Combinatorial Model of Interference in Frequency Hopping Schemes
In a frequency hopping (FH) scheme users communicate simultaneously using FH
sequences defined on the same set of frequency channels. An FH sequence
specifies the frequency channel to be used as communication progresses. Much of
the research on the performance of FH schemes is based on either pairwise
mutual interference or adversarial interference but not both. In this paper, we
evaluate the performance of an FH scheme with respect to both group-wise mutual
interference and adversarial interference (jamming), bearing in mind that more
than two users may be transmitting simultaneously in the presence of a jammer.
We establish a correspondence between a cover-free code and an FH scheme. This
gives a lower bound on the transmission capacity. Furthermore, we specify a
jammer model and consider what additional properties a cover-free code should
have to resist the jammer. We demonstrate that a purely combinatorial approach
is inadequate against such a jammer, but that with the use of pseudorandomness,
we can have a system that has high throughput as well as security against
jamming.Comment: 18 pages, submitted to journa
Frequency hopping sequences with optimal partial Hamming correlation
Frequency hopping sequences (FHSs) with favorable partial Hamming correlation
properties have important applications in many synchronization and
multiple-access systems. In this paper, we investigate constructions of FHSs
and FHS sets with optimal partial Hamming correlation. We first establish a
correspondence between FHS sets with optimal partial Hamming correlation and
multiple partition-type balanced nested cyclic difference packings with a
special property. By virtue of this correspondence, some FHSs and FHS sets with
optimal partial Hamming correlation are constructed from various combinatorial
structures such as cyclic difference packings, and cyclic relative difference
families. We also describe a direct construction and two recursive
constructions for FHS sets with optimal partial Hamming correlation. As a
consequence, our constructions yield new FHSs and FHS sets with optimal partial
Hamming correlation.Comment: 16 pages. arXiv admin note: text overlap with arXiv:1506.0737
Sets of Zero-Difference Balanced Functions and Their Applications
Zero-difference balanced (ZDB) functions can be employed in many
applications, e.g., optimal constant composition codes, optimal and perfect
difference systems of sets, optimal frequency hopping sequences, etc. In this
paper, two results are summarized to characterize ZDB functions, among which a
lower bound is used to achieve optimality in applications and determine the
size of preimage sets of ZDB functions. As the main contribution, a generic
construction of ZDB functions is presented, and many new classes of ZDB
functions can be generated. This construction is then extended to construct a
set of ZDB functions, in which any two ZDB functions are related uniformly.
Furthermore, some applications of such sets of ZDB functions are also
introduced.Comment: 20 page
A Construction of Optimal Frequency Hopping Sequence Set via Combination of Multiplicative and Additive Groups of Finite Fields
In literatures, there are various constructions of frequency hopping sequence
(FHS for short) sets with good Hamming correlations. Some papers employed only
multiplicative groups of finite fields to construct FHS sets, while other
papers implicitly used only additive groups of finite fields for construction
of FHS sets. In this paper, we make use of both multiplicative and additive
groups of finite fields simultaneously to present a construction of optimal FHS
sets. The construction provides a new family of optimal
frequency
hopping sequence sets archiving the Peng-Fan bound. Thus, the FHS sets
constructed in literatures using either multiplicative groups or additive
groups of finite fields are all included in our family. In addition, some other
FHS sets can be obtained via the well-known recursive constructions through
one-coincidence sequence set
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