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Cross-entropy-based joint carrier frequency offset estimation and multiuser detection for multicarrier code division multiple access systems

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2013年第8期26卷 964-973页

作者： Lain, Jenn-Kaie Yang, Shang-Yi Lin, Chih-Wei Natl Yunlin Univ Sci & Technol Dept Elect Engn Touliu 640 Yunlin Taiwan

This paper presents a joint carrier frequency offset estimation and multiuser detection based on a maximum likelihood approach in multicarrier code division multiple access systems. With the definition of a score function based on the log-likelihood, the joint carrier frequency offset estimation and multiuser detection can be formulated as a nonlinear optimization problem over the joint of a multidimensional real space and a multidimensional discrete space. To reduce the computational complexity required by the joint decision statistic, while still obtaining a desirable performance, a new method using cross-entropy optimization is proposed to solve the nonlinear optimization problem. Because of the robustness of the cross-entropy optimization, the joint decision statistic can be efficiently solved, and, as shown by the furnished simulation results, the proposed approach can achieve satisfactory performance in various scenarios. Copyright (c) 2011 John Wiley & Sons, Ltd.

关键词： cross-entropy optimization frequency offset multicarrier code division multiple access multiuser detection

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Performance analysis of closed-loop pre-equalisation for multiuser multiple-input multiple-output with multicarrier code division multiple access systems

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IET COMMUNICATIONS 2016年第3期10卷 235-244页

作者： Martin Luna-Rivera, Jose Ulises Campos-Delgado, Daniel Gutierrez, Carlos A. Covarrubias-Rosales, David H. UASLP Fac Ciencias Av Salvador Nava S-N Zona Univ Slp Mexico CICESE Dept Elect & Telecomunicac Ensenada Baja California Mexico

The use of multiple transmit and receive antennas is widely recognised as an effective technology to boost the capacity of wireless communication systems. Moreover, the combination of multiple-input multiple-output (MIMO) systems with multicarrier code division multiple access (MC-CDMA) offers a strong alternative to satisfy the demand for high data rates with rigorous quality-of-service (QoS) restrictions. In this study, this paper applies a closed-loop pre-equalisation methodology under a unified framework for MIMO and MC-CDMA systems that satisfies the QoS target with a single-user-based detector while minimising the power of the pre-equalisation factors. It is of particular interest to investigate the impact and limitations of combining the robustness of the feedback scheme with the degrees of freedom available in the system, given in terms of the number of subcarriers and multiple antennas. The contribution of this work includes the derivation of the distributed and centralised optimal closed-loop pre-equalisation solutions under the MIMO-MC-CDMA structure. The results and analysis illustrate important gains in the form of power savings, enabled by the spatial diversity of the MIMO scheme.

关键词： MIMO communication quality of service code division multiple access closed-loop preequalisation multiuser multiple-input multiple-output system MIMO system multicarrier code division multiple access MC-CDMA system wireless communication system quality-of-service QoS centralised optimal closed-loop preequalisation power savings

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Blind uplink space-time channel estimation for space-time coded multicarrier code division multiple access systems

Blind uplink space-time channel estimation for space-time co...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Yanxing Zeng Qinye Yin Le Ding Ke Deng School of Electrical and Information Engineering Xi'an Jiaotong University China

ISBN: (纸本)078038251X

The uplink of a space-time coded multicarrier code division multiple access (MS-CDMA) system equipped with a uniform linear array (ULA) at the base station is investigated. Transmission takes place over frequency-selective fading channels and the goal is to blindly estimate the space-time channels and the directions of arrival (DOA) for all active users in one macrocell. An auxiliary matrix including both uplink space-time channels and DOAs is constructed, on which the eigen decomposition is performed to acquire the DOAs for multiple users. Then, the singular value decomposition (SVD) is applied on the eigenvectors corresponding to the DOA of individual user to obtain a closed-form solution of the uplink space-time vector channel. Computer simulations demonstrate the effectiveness of the proposed scheme.

关键词： Channel estimation multicarrier code division multiple access Direction of arrival estimation Base stations Frequency-selective fading channels Frequency estimation Macrocell networks Matrix decomposition Singular value decomposition Closed-form solution

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Direct decoding of uplink space-time block coded multicarrier code division multiple access systems

Direct decoding of uplink space-time block coded multicarrie...

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IEEE International Conference on Communications (ICC)

作者： Yanxing Zeng Qinye Yin Yivven Zhang Ke Deng Ming Luo Aifeng Ren School of Electronics and Information Engineering Xi''an Jiaotong University China

ISBN: (纸本)0780385330

The uplink of a space-time block coded multicarrier code division multiple access (MC-CDMA) system endowed with a uniform linear array (ULA) at the base station of macrocell is studied. Transmission takes place over frequency-selective fading channels and the transmitted symbol of a user is encoded by Tarokh's rate 1 space-time block encoder, (V. Tarokh and H. Jafarkhani, July 1999) from real orthogonal design, with three transmit antennas. An algorithm is proposed to blindly estimate the data symbol sequence and the direction of arrival (DOA) of each user without determining the space-time vector channels. The algorithm employs an ESPRIT- like method (Y. Zeng et al.) to separate multiple co-channel users with different impinging DOAs, then exploits the structure of space- time block coding (STBC) in combination with the subspace method to estimate the original symbol sequences for multiple users. In particular, the theoretical analysis shows that the signal subspace defined by the received data covariance matrix can be separated by users' DOA, so the joint diagonalization step of many matrices due to the method presented by A. Swindlehurst (April 2002) is avoided, which saves large computations. Computer simulations illustrate the overall performances of the proposed algorithm.

关键词： Decoding multicarrier code division multiple access Direction of arrival estimation Covariance matrix Linear antenna arrays Base stations Macrocell networks Frequency-selective fading channels Transmitting antennas Block codes

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BER performance evaluation for multicarrier code division multiple access over generalized k-μ fading channels

BER performance evaluation for multicarrier code division mu...

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IEEE Symposium on Computers & Informatics (ISCI)

作者： James Osuru Mark Brahim Belhaouari Samir Mohammed Naufal Department of Electrical & Electronic Engineering Universiti Teknologi Petronas Bandar Seri Iskandar Tronoh Perak Malaysia

multicarrier code division multiple access (MC-CDMA) system has received a considerable attention from researchers owing to its great potential in achieving high data rates transmission in wireless communications. Due to the detrimental effects of multipath fading the performance of the system degrades. Similarly, the impact of non-orthogonality of spreading codes can exist and cause interference. This paper addresses the performance of multicarrier code division multiple access system under the influence of frequency selective generalized k-μ fading channel and multiple access interference caused by other active users to the desired one. The average bit error rate is derived and expressed in Gauss hypergeometric functions. Maximal ratio combining diversity technique is utilized to alleviate the deleterious effect of multipath fading.

关键词： Fading Bit error rate multicarrier code division multiple access Diversity reception Signal to noise ratio Interference

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coded multicarrier code division multiple access

Coded multicarrier code division multiple access

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IEEE International Symposium on Information Theory

作者： D.N. Rowitch L.B. Milstein Department of Electrical and Computer Engineering University of California San Diego CA USA

This paper presents a multicarrier signaling technique for an asynchronous direct sequence (DS) code division multiple access (CDMA) system which employs linear convolutional codes to achieve performance gains in exce... 详细信息

关键词： multicarrier code division multiple access Bandwidth Multiaccess communication Convolutional codes Convolution Multipath channels Fading Frequency diversity Correlators Decoding

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Time-Hopping multicarrier code-division multiple-access: System Outline and Performance

Time-Hopping Multicarrier Code-Division Multiple-Access: Sys...

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IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： Lie-liang Yang School of ECS University of Southampton UK

A time-hopping multicarrier code-division multiple-access (TH/MC-CDMA) scheme is proposed and investigated. In the proposed TH/MC-CDMA each information symbol is transmitted by a number of time-domain pulses with each time-domain pulse modulating a subcarrier. The transmitted information at the receiver is extracted from one of the, say M, possible time-slot positions, i.e., assuming that M-ary pulse position modulation is employed. Specifically, in this contribution we concentrate on the scenarios such as system design, power spectral density (PSD) and signal detection. The error performance of the TH/MC-CDMA system is evaluated, when the channel that each subcarrier signal experiences is modeled as flat Nakagami-m fading in addition to the additive white Gaussian noise (AWGN). According to our analysis and results, it can be shown that the TH/MC-CDMA signal is capable of providing a near ideal PSD, which is flat over the system bandwidth available, while decreases rapidly beyond that bandwidth. Explicitly, signals having this type of PSD is beneficial to both broadband and ultra-wide bandwidth (UWB) communications. Furthermore, our results show that, when optimum user address codes are employed, the single-user detector considered is near-far resistant, provided that the number of users supported by the system is lower than the number of subcarriers used for conveying a information symbol

关键词： Multiaccess communication Pulse modulation multicarrier code division multiple access AWGN Bandwidth Time domain analysis Data mining System analysis and design Signal detection Power system modeling

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Two Constructions of Aperiodic Quasi-Complementary Sequence Sets With New Parameters

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IEEE TRANSACTIONS ON COMMUNICATIONS 2025年第1期73卷 93-102页

作者： Wang, Meiyue Liu, Tao Liu, Mingxin Li, Yubo Yanshan Univ Sch Informat Sci & Engn Qinhuangdao 066004 Peoples R China Hebei Key Lab Informat Transmiss & Signal Proc Qinhuangdao 066004 Peoples R China Guangdong Ocean Univ Coll Elect & Informat Engn Zhanjiang 524088 Peoples R China

Quasi-complementary sequence sets (QCSSs) have attracted sustained research interests due to the ability to support more users compared to complete complementary codes (CCCs) in multi-carrier code division multiple access (MC-CDMA) systems. In this paper, two classes of aperiodic QCSSs are constructed over the finite rings, which have new parameters in terms of the length of constituent sequences and set size respectively. Most notably, the length of constituent sequences of QCSS derived from the first construction is p(n) + 1, where p is a prime and n is a positive integer, which has not been covered in the literature. In the second construction, the set size of the proposed binary QCSS is 2(n+1) larger than the existing binary QCSS. In addition, both the proposed aperiodic QCSSs are asymptotically optimal with respect to the correlation lower bound.

关键词： Correlation Galois fields Additives multicarrier code division multiple access Peak to average power ratio Systematics Interference Quasi-complementary sequence sets (QCSSs) finite ring multi-carrier code division multiple access (MC-CDMA) asymptotically optimal

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Quasi Complementary Sequence Sets: New Bounds and Optimal Constructions via Quasi-Florentine Rectangles

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IEEE TRANSACTIONS ON INFORMATION THEORY 2025年第3期71卷 2271-2291页

作者： Adhikary, Avik Ranjan Zhang, Hui Zhou, Zhengchun Wang, Qi Mesnager, Sihem Southwest Jiaotong Univ Sch Math Chengdu 611756 Peoples R China Henan Normal Univ Sch Math & Stat Xinxiang 453007 Peoples R China Southern Univ Sci & Technol Natl Ctr Appl Math Dept Comp Sci & Engn Shenzhen 518055 Peoples R China Univ Paris VIII Dept Math F-93526 St Denis France Univ Paris XIII CNRS UMR LAGA 7539 F-93430 Villetaneuse France Polytech Inst Paris Telecom Paris F-91120 Palaiseau France

Quasi complementary sequence sets (QCSSs) are important in modern communication systems as they are capable of supporting more users, which is desired in applications like MC-CDMA nowadays. In this paper, we first derive a tighter bound on the maximum aperiodic correlation among all constituent complementary sequence sets in QCSSs. By proposing a new combinatorial structure called quasi-Florentine rectangles, we obtain a new construction of QCSSs with large set sizes. Using Butson-type Hadamard matrices and quasi-Florentine rectangles, we propose another construction which can construct QCSSs with flexible parameters over any given alphabet size, including small alphabets. All the proposed sequences are optimal with respect to the newly proposed bound. Also, through some of the constructions, the column sequence PMEPR of the proposed QCSSs are upper bounded by 2.

关键词： Correlation Mathematics multicarrier code division multiple access Systematics Error correction codes Error correction Lower bound Spectroscopy Radar applications Postal services Correlation bound complementary set (CS) quasi complementary sequence set (QCSS) quasi-Florentine rectangle

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Performance of code division multiple access CDMA systems in Nakagami multipath fading channel 18

Performance of code division multiple access CDMA systems in...

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18th National Radio Science Conference (NRSC 2001)

作者： Elnoubi, SM Hashem, AA Univ Alexandria Fac Engn Alexandria Egypt

ISBN: (纸本)9775031680

Multi Carrier CDMA system is characterized by a simpler receiver structure than the conventional RAKE receiver [1], [2]. Most of previous studies evaluated the performance of MC-CDMA system in Rayleigh multipath fading channel [1]. This paper compares the performances of RAKE receiver and MC-CDMA system in Nakagami multipath, fading. The Nakagami model, known as m-distribution model, is a generalized model as it includes Gaussian, Rayleigh and Rice fading as special cases by changing the Nakagami parameter in [3], [4]. On the other hand, Nakagami model has been shown by many literatures to be the closest model to the indoor mobile radio channel [5], [6], [4]. According to our analysis, we found that the MC-CDMA system outperforms the practical RAKE receiver, in which die number of RAKE fingers is less than the maximum resolvable paths of die channel. Moreover, MC-CDMA system outperforms the RAKE receiver in lower diffusive channels.

关键词： Correlators Direct-sequence code-division multiple access Fading Fingers Multiaccess communication multicarrier code division multiple access Nakagami distribution RAKE receivers Rayleigh channels System performance

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