11 research outputs found
Two-Dimensional Z-Complementary Array Quads with Low Column Sequence PMEPRs
In this paper, we first propose a new design strategy of 2D -complementary
array quads (2D-ZCAQs) with feasible array sizes. A 2D-ZCAQ consists of four
distinct unimodular arrays satisfying zero 2D auto-correlation sums for
non-trivial 2D time-shifts within certain zone. Then, we obtain the upper
bounds on the column sequence peak-to-mean envelope power ratio (PMEPR) of the
constructed 2D-ZCAQs by using specific auto-correlation properties of some seed
sequences. The constructed 2D-ZCAQs with bounded column sequence PMEPR can be
used as a potential alternative to 2D Golay complementary array sets for
practical applicationsComment: This work has been presented in 2023 IEEE International Symposium on
Information Theory (ISIT), Taipei, Taiwa
A direct construction of even length ZCPs with large ZCZ ratio
This paper presents a direct construction of aperiodic q-ary (q is a positive even integer) even length Z-complementary pairs (ZCPs) with large zero-correlation zone (ZCZ) width using generalised Boolean functions (GBFs). The applicability of ZCPs increases with the increasing value of ZCZ width, which plays a significant role in reducing interference in a communication system with asynchronous surroundings. For q = 2, the proposed ZCPs reduce to even length binary ZCPs (EB-ZCPs). However, to the best of the authors’ knowledge, the highest ZCZ ratio for even length ZCPs which are directly constructed to date using GBFs is 3/4. In the proposed construction, we provide even length ZCPs with ZCZ ratios 5/6 and 6/7, which are the largest ZCZ ratios achieved to date through direct construction.acceptedVersio
Direct Construction of Optimal Z-Complementary Code Sets for all Possible Even Length by Using Pseudo-Boolean Functions
Z-complementary code set (ZCCS) are well known to be used in multicarrier
code-division multiple access (MCCDMA) system to provide a interference free
environment. Based on the existing literature, the direct construction of
optimal ZCCSs are limited to its length. In this paper, we are interested in
constructing optimal ZCCSs of all possible even lengths using Pseudo-Boolean
functions. The maximum column sequence peakto-man envelop power ratio (PMEPR)
of the proposed ZCCSs is upper-bounded by two, which may give an extra benefit
in managing PMEPR in an ZCCS based MC-CDMA system, as well as the ability to
handle a large number of users
A Direct and Generalized Construction of Polyphase Complementary Set with Low PMEPR and High Code-Rate for OFDM System
A major drawback of orthogonal frequency division multiplexing (OFDM) systems
is their high peak-to-mean envelope power ratio (PMEPR). The PMEPR problem can
be solved by adopting large codebooks consisting of complementary sequences
with low PMEPR. In this paper, we present a new construction of polyphase
complementary sets (CSs) using generalized Boolean functions (GBFs), which
generalizes Schmidt's construction in 2007, Paterson's construction in 2000 and
Golay complementary pairs (GCPs) given by Davis and Jedwab in 1999. Compared
with Schmidt's approach, our proposed CSs lead to lower PMEPR with higher
code-rate for sequences constructed from higher-order () GBFs. We
obtain polyphase complementary sequences with maximum PMEPR of and
where are non-negative integers that can be easily derived
from the GBF associated with the CS
Pseudo-Boolean Functions for Optimal Z-Complementary Code Sets with Flexible Lengths
This paper aims to construct optimal Z-complementary code set (ZCCS) with non-power-of-two (NPT) lengths to enable interference-free multicarrier code-division multiple access (MC-CDMA) systems. The existing ZCCSs with NPT lengths, which are constructed from generalized Boolean functions (GBFs), are sub-optimal only with respect to the set size upper bound. For the first time in the literature, we advocate the use of pseudo-Boolean functions (PBFs) (each of which transforms a number of binary variables to a real number as a natural generalization of GBF) for direct constructions of optimal ZCCSs with NPT lengths
Optimal Z -Complementary Code Set From Generalized Reed-Muller Codes
Z-complementary code set (ZCCS), an extension of perfect CCs, refers to a set of 2-D matrices having zero correlation zone properties. ZCCS can be used in various multi-channel systems to support, for example, quasi-synchronous interference-free multicarrier code-division multiple access communication and optimal channel estimation in multiple-input multiple-output systems. Traditional constructions of ZCCS heavily rely on a series of sequence operations which may not be feasible for rapid hardware generation particularly for long ZCCSs. In this paper, we propose a direct construction of ZCCS using the second-order Reed-Muller codes with efficient graphical representation. Our proposed construction, valid for any number of isolated vertices present in the graph, is capable of generating optimal ZCCS meeting the set size upper bound