15 research outputs found
The Construction and Performance of a Novel Intergroup Complementary Code
 On the basis of the analyses for intergroup complementary (IGC) code and zero correlation zone complementary code, a novel IGC code has been proposed to adapt M-ary orthogonal code spreading spectrum system or quasi-synchronous CDMA system. The definition and construction methods of the new IGC codes are presented and an applied example is given in this paper. Theoretical research and simulation results show that the main advantages of the novel IGC code are as following: The code sets of the novel IGC code is more than IGC code under the same code length. The zero correlation zone length is longer than the intergroup IGC code, but shorter than the intergroup IGC code. Under the same code length, the auto-correlation performance of the novel IGC code is better than that of the IGC code, and both are of similar cross-correlation performance
A Direct Construction of Prime-Power-Length Zero-Correlation Zone Sequences for QS-CDMA System
In recent years, zero-correlation zone (ZCZ) sequences are being studied due
to their significant applications in quasi-synchronous code division multiple
access (QS-CDMA) systems and other wireless communication domains. However, the
lengths of most existing ZCZ sequences are limited, and their parameters are
not flexible, which are leading to practical limitations in their use in
QS-CDMA and other communication systems. The current study proposes a direct
construction of ZCZ sequences of prime-power length with flexible parameters by
using multivariable functions. In the proposed construction, we first present a
multivariable function to generate a vector with specific properties; this is
further used to generate another class of multivariable functions to generate
the desired -ZCZ sequence set, where is a prime
number, are positive integers, and . The constructed ZCZ
sequence set is optimal for the binary case and asymptotically optimal for the
non-binary case by the \emph{Tang-Fan-Matsufuji} bound. Moreover, a relation
between the second-order cosets of first-order generalized Reed-Muller code and
the proposed ZCZ sequences is also established. The proposed construction of
ZCZ sequences is compared with existing constructions, and it is observed that
the parameters of this ZCZ sequence set are a generalization of that of in some
existing works. Finally, the performance of the proposed ZCZ-based QS-CDMA
system is compared with the Walsh-Hadamard and Gold code-based QS-CDMA system
Low-PMEPR Preamble Sequence Design for Dynamic Spectrum Allocation in OFDMA Systems
Orthogonal Frequency Division Multiple Access (OFDMA) with Dynamic spectrum allocation (DSA) is able to provide a wide range of data rate requirements. This paper is focused on the design of preamble sequences in OFDMA systems with low peak-to-mean envelope power ratio (PMEPR) property in the context of DSA. We propose a systematic preamble sequence design which gives rise to low PMEPR for possibly non-contiguous spectrum allocations. With the aid of Golay-Davis-Jedwab (GDJ) sequences, two classes of preamble sequences are presented. We prove that their PMEPRs are upper bounded by 4 for any DSA over a chunk of four contiguous resource blocks
Large Zero Autocorrelation Zone of Golay Sequences and -QAM Golay Complementary Sequences
Sequences with good correlation properties have been widely adopted in modern
communications, radar and sonar applications. In this paper, we present our new
findings on some constructions of single -ary Golay sequence and -QAM
Golay complementary sequence with a large zero autocorrelation zone, where
is an arbitrary even integer and is an arbitrary integer.
Those new results on Golay sequences and QAM Golay complementary sequences can
be explored during synchronization and detection at the receiver end and thus
improve the performance of the communication system
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