Zero Correlation Zone Sequence Sets Research Articles

Novel quadriphase ZCZ sequences for QS-CDMA systems

In this article, a novel method for constructing quadriphase Zero Correlation Zone (ZCZ) sequence sets based on the mutually orthogonal complementary sets (MOCS) matrix and polyphase perfect sequence is presented. Based on the obtained MATLAB results in terms of correlation functions, it can be mentioned that the resultant ZCZ set is suitable for quasi-synchronous Code Division Multiple Access (QS-CDMA) systems. The obtained sequence sets are near-optimal concerning mathematical bound, and their construction is more flexible than other polyphase ZCZ constructions. Furthermore, their parameters can be chosen flexibly.

Exact Analysis of MIMO Channel Estimation Based on Superimposed Training

In this paper, channel estimation capabilities of a multiple-input multiple-output (MIMO) system using superimposed training sequences are investigated. A new expression for estimation-error variance is derived. It is shown that the training sequences must be balanced and must have specific correlation properties. The latter are required only in a specific zone. Sequences that satisfy these criteria exist and are referred to as zero-correlation zone (ZCZ) solutions. Consequently, by using balanced ZCZ sequences, harmful direct current (DC) offset can be removed. Owing to their zero-cross correlation, interference from other transmitting antennas may be eliminated. Furthermore, a closed-form expression of the estimation-error variance can be obtained due to their impulse-like autocorrelation. To increase the number of antennas in the MIMO system, a new construction of ZCZ sequence set is proposed, in which all sequences are balanced

Construction of Multiple Optimal Polyphase Zero Correlation Zone Sequence Sets With Inter-Set Zero Cross-Correlation Zone

Based on DFT matrices and no-hit-zone (NHZ) frequency hopping sequence sets, a construction of multiple optimal polyphase zero correlation zone sequence sets with inter-set zero cross-correlation zone (ZCCZ) is proposed. The parameters of each subset are optimal, and arbitrary two sequences from different subsets have the same inter-set ZCCZ. Furthermore, new NHZ frequency hopping sequence sets are proposed, which can be used in the construction of multiple polyphase ZCZ sequence sets with inter-set ZCCZ. The resultant sequence sets presented in this letter can be applied to multi-cell QS-CDMA systems.

Construction of optimal zero correlation zone sequence set

Construction of optimal zero correlation zone sequence set

Polyphase zero correlation zone sequences from generalised bent functions

Sequence families with zero correlation zone (ZCZ) have been extensively studied in recent years due to their important applications in quasi-synchronous code-division multiple-access (QS-CDMA) systems. To accommodate multiuser environments, multiple ZCZ sequence sets with low inter-set cross-correlation are expected. In this paper, we propose a construction of polyphase ZCZ sequences based on generalised bent functions. Moreover, multiple polyphase ZCZ sequence sets with good inter-set cross-correlation are presented. Each generated ZCZ sequence set is optimal with respect to the Tang-Fan-Matsufuji bound.

Constructions of polyphase ZCZ sequence sets with low cross‐correlation property

Zero correlation zone (ZCZ) sequences have received much research attention in many practical applications, such as quasi-synchronous code-division multiple-access systems and MIMO systems. In this study, three constructions of multiple polyphase ZCZ sequence sets with low inter-set cross-correlation property are proposed. The resultant periodic ZCZ sequence sets are optimal with respect to the theoretical bound and have new parameters uncovered in the literature. Consequently, a great deal of flexibility may be provided in the choice of periodic optimal ZCZ sequence sets with good inter-set cross-correlation property for their applications.

A Generic Construction of Mutually Orthogonal Optimal Binary ZCZ Sequence Sets

In this letter, a generic method to construct mutually orthogonal binary zero correlation zone (ZCZ) sequence sets from mutually orthogonal complementary sequence sets (MOCSSs) with certain properties is presented at first. Then MOCSSs satisfying conditions are generated from binary orthogonal matrices with order N×N, where N=p-1, p is a prime. As a result, mutually orthogonal binary ZCZ sequence sets with parameters (2N2,N,N+1)-ZCZ can be obtained, the number of ZCZ sets is N. Note that each single ZCZ sequence set is optimal with respect to the theoretical bound.

A Novel Class of Structured Zero-Correlation Zone Sequence Sets

A Novel Class of Structured Zero-Correlation Zone Sequence Sets

Golay Complementary Sequence Sets With Large Zero Correlation Zones

Zero correlation zone (ZCZ) sequence sets and Golay complementary sets (GCSs) have different correlation properties and hence have different engineering applications. A number of constructions of ZCZ sequence sets and GCSs have been proposed, respectively, in the literature. In addition, some ZCZ sequence sets can be constructed from mutually orthogonal GCSs. In this paper, the relationship between GCSs and ZCZ sets is discovered further. We propose a new type of sequence sets which are ZCZ sequence sets and also GCSs. They are called the Golay-ZCZ sequence sets in this paper. Therefore, they have low peak-to-average power ratios when employed in OFDM systems due to the good autocorrelation properties of GCSs. Besides, the Golay-ZCZ sets possess zero autocorrelations and cross-correlations within their ZCZ and hence have the potential application to synchronization. Furthermore, a construction of Golay-ZCZ sequence family with flexible set sizes, various sequence lengths, and large ZCZ widths is proposed in this paper.

Efficient Mutually Orthogonal Golay Complementary Set-Based Zero-Correlation Zone Sequence Set Correlator

An efficient implementation of zero-correlation-zone (ZCZ) sequence set correlators is of particular interest for integrated circuit realizations of phase-coded continuous-wave multiple-input multiple-output radar systems. Such systems require a correlation with all transmitted sequence set members at every receiver. We present an approach for an efficient circuit realization of such a sequence set correlator for a subset of mutually orthogonal Golay complementary set-based ZCZ sequence sets. Furthermore, we analyze and optimize the resource requirement. A logarithmic instead of a linear growth of the required adders could be achieved by the proposed implementation.

A Construction of Multiple Optimal ZCZ Sequence Sets With Good Cross Correlation

Zero correlation zone (ZCZ) sequences are a class of spreading sequences having ideal auto-correlation and cross correlation in a zone around the origin. They have been extensively studied in recent years due to their important applications in quasi-synchronous code division multiple access systems. In this paper, a construction of ZCZ sequence sets is proposed based on perfect nonlinear functions. It generates multiple ZCZ sequence sets with the properties: 1) each sequence is perfect in the sense that its out-of-phase auto-correlation is always zero; 2) each ZCZ sequence set is optimal with respect to the Tang–Fan–Matsufuji bound in which all the sequences are pairwise cyclically distinct; and 3) the maximum inter-set cross correlation of multiple sequence sets achieves the well-known Sarwate bound.

Construction of Zero Correlation Zone Sequence Sets over the 16-QAM Constellation

Construction of Zero Correlation Zone Sequence Sets over the 16-QAM Constellation

An asymmetric ZCZ sequence set with inter-subset uncorrelated property and flexible ZCZ length

In this paper, we propose a novel method for constructing new uncorrelated asymmetric zero correlation zone (UA-ZCZ) sequence sets by interleaving perfect sequences. As a type of ZCZ sequence set, an A-ZCZ sequence set consists of multiple sequence subsets. Different subsets are correlated in conventional A-ZCZ sequence set but uncorrelated in our scheme. In other words, the cross-correlation function (CCF) between two arbitrary sequences which belong to different subsets has quite a large zero cross-correlation zone (ZCCZ). Analytical results demonstrate that the UA-ZCZ sequence set proposed herein is optimal with respect to the upper bound of ZCZ sequence set. Specifically, our scheme enables the flexible selection of ZCZ length, which makes it extremely valuable for designing spreading sequences for quasi-synchronous code-division multiple-access (QS-CDMA) systems.

Constructions of Zero Correlation Zone Sequence Sets with Low Cross-Correlation Property

Constructions of Zero Correlation Zone Sequence Sets with Low Cross-Correlation Property

A ternary zero-correlation zone sequence sets construction procedure

In the present paper, we propose ternary zero-correlation zone (ZCZ) sequence sets with ideal correlation properties for phase shifts within the ZCZ. The proposed ternary ZCZ sequence sets can be constructed from binary mutually orthogonal complementary sets (MOCS) and ternary perfect sequences.

A Novel Construction of Tree-Structured Zero-Correlation Zone Sequence Sets

A Novel Construction of Tree-Structured Zero-Correlation Zone Sequence Sets

A Novel Class of Quadriphase Zero-Correlation Zone Sequence Sets

A Novel Class of Quadriphase Zero-Correlation Zone Sequence Sets

Joint timing synchronization and channel estimation based on ZCZ sequence set in SC-MIMO-FDE system

In this paper, we investigate the channel estimation and time synchronization problem based on the zero correlation zone (ZCZ) sequence set for single carrier multiple-input multiple-output frequency domain equalization (SC-MIMO-FDE). A factorized construction of ZCZ sequence set considering the properties of both ZCZ and nonzero correlation zone (NCZ) is proposed with efficient generator and correlator, which can be in favor of timing synchronization and channel estimation both in performance and computation complexity. Using the ZCZ sequence set, a new algorithm called twice section-maximum algorithm is put forward to eliminate energy interference among channels from different transmitting antennas to the same receiving antenna. The performance achieved by the developed algorithm which performs joint timing synchronization and channel estimation with lower computational cost is better than that of the conventional method.

A Novel Class of Zero-Correlation Zone Sequence Set Having a Low Peak-Factor and a Flat Power Spectrum

A Novel Class of Zero-Correlation Zone Sequence Set Having a Low Peak-Factor and a Flat Power Spectrum

Ternary Zero Correlation Zone Sequence Sets for Asynchronous DS-CDMA

In this paper we propose a new class of ternary Zero Correlation Zone (ZCZ) sequence sets based on binary ZCZ sequence sets construction. It is shown that the proposed ternary ZCZ sequence sets can reach the upper bound on the ZCZ sequences. The performance of the proposed sequences set in asynchronous Direct Sequence-Code Division Multiple Access (DS-CDMA) system is evaluated. In the simulation we used two types of channels: Additive White Gaussian Noise (AWGN) and frequency non-selective fading with AWGN noise. The proposed ternary ZCZ sequence sets show better results, in term of Bit Error Rate (BER), than Hayashi’s ternary ZCZ sequence sets.