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Multistation data fusion for code-division multiple access wireless communications

OPTICAL ENGINEERING 2003年第6期42卷 1572-1582页

作者： Tian, Z Chang, KC Michigan Technol Univ Dept Elect & Comp Engn Houghton MI 49931 USA George Mason Univ Syst Engn & Operat Res Dept Fairfax VA 22030 USA

Data fusion is the study of optimal information processing in distributed multisensor environments with the benefits of more reliable detection and higher immunity to noise and sensor failures. We investigate applications of the data fusion principle to the handoff problem in popular code-division multiple access (CDMA) cellular wireless communication networks. When a mobile station traverses a cell boundary, cell handoff is required to make the transition of a mobile between cells smoother without degrading performance. CDMA multiple access allows soft handoff, in which the signal strength of the mobile is detected and tracked by the searchers from more than one base station. The cell receiving the strongest signal strength handles signal processing. We demonstrate that the signal detection quality in the handoff region can be further improved by fusing the detected results from multiple base stations. A new fusion handoff strategy is designed, and its error performance measures are derived analytically in the presence of log-normal shadowing. Theoretical fading margin analysis shows that the fusion handoff approach offers better network performance over conventional hard and soft handoffs. (C) 2003 Society of Photo-Optical Instrumentation Engineers.

关键词： data fusion code-division multiple access wireless networks handoff strategies performance analysis

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MODIFICATION OF OPTICAL COHERENCE USING SPECTRAL PHASE CODING FOR USE IN PHOTONIC code-division multiple-access SYSTEMS

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ELECTRONICS LETTERS 1993年第25期29卷 2214-2216页

作者： GRIFFIN, RA SAMPSON, DD JACKSON, DA UNIV MELBOURNE DEPT ELECT & ELECTR ENGNPHOTON RES LABPARKVILLEVIC 3052AUSTRALIA

The authors experimentally demonstrate coding and decoding of optical data using a passive spectral phase coding technique to modify the optical coherence of transmitted signals. Potential application to multiaccess c... 详细信息

关键词： OPTICAL COMMUNICATIONS code-division multiple access

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Image transmission in multicore-fiber code-division multiple access network

Image transmission in multicore-fiber code-division multiple...

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Conference on Video Techniques and Software for Full-Service Networks

作者： Yang, GC Kwong, WC National Chung-Hsing Univ. (Taiwan) Hofstra Univ. (United States)

ISBN: (纸本)0819423173

Recently, two-dimensional (2-D) signature patterns were proposed to encode binary digitized image pixels in optical code-division multiple-access (CDMA) networks with ''multicore'' fiber. The new technology enables parallel transmission and simultaneous access of 2-D images in multiple-access environment, where these signature patterns are defined as optical orthogonal signature pattern codes (OOSPCs). However, previous work on OOSPCs assumed that the weight of each signature pattern was the same, In this paper, we construct a new family of OOSPCs with the removal of this assumption, Since varying the weight of a user's signature pattern affects that user's performance, this approach is useful for CDMA optical systems with multiple performance requirements.

关键词： code-division multiple access optical orthogonal signature pattern code parallel transmission optical networks

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An efficient data transmission technique for VLSI systems using multiple-valued code-division multiple access

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IEICE TRANSACTIONS ON ELECTRONICS 2002年第8期E85C卷 1581-1587页

作者： Yuminaka, Y Sakamoto, S Gunma Univ Fac Engn Kiryu Gumma 3768515 Japan

This paper investigates multiple-valued codedivision multiple access (MV-CDMA) techniques and circuits for intra/inter-chip communication to achieve efficient data transmission in VLSI systems. To address the problems caused by interconnection complexity, we transmit multiplexed signals inside LSI systems employing pseudo-random orthogonal m-sequences as information carriers. A new class of multiple-valued CDMA techniques for intra-chip communication is discussed to demonstrate the feasibility of eliminating co-channel interference caused by a propagation delay of signals, e.g., clock skew. This paper describes the circuit configuration and performance evaluation of MV-CDMA systems for intra-chip communication. We first explain the principle of MV-CDMA technique, and then propose a bidirectional current-mode CMOS technique to realize compact correlation circuits for CDMA. Finally, we show the Spice and MATLAB simulation results of MV-CDMA systems, which indicate the excellent capabilities of eliminating co-channel interference.

关键词： VLSI systems code-division multiple access m-sequence new paradigm computing current-mode MOS circuits

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Redundant Residue Number System Assisted Multicarrier Direct-Sequence code-division Dynamic multiple access for Cognitive Radios

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2012年第3期61卷 1234-1250页

作者： Zhang, Shuo Yang, Lie-Liang Zhang, Youguang Beihang Univ Sch Elect & Informat Engn Beijing 100191 Peoples R China Univ Southampton Sch Elect & Comp Sci Southampton SO17 1BJ Hants England

A redundant residue number system (RRNS)-assisted multicarrier direct-sequence code-division dynamic multiple-access (MC/DS-CDDMA) scheme is proposed for application in cognitive radios (CRs). Taking the advantages of both multicarrier direct-sequence code-division multiple access and RRNS, the RRNS MC/DS-CDDMA has a low complexity for implementation and a high flexibility for reconfiguration and is robust to dynamic spectrums. Associated with the RRNS MC/DS-CDDMA, in this paper, the so-called receiver multiuser diversity aided multistage minimum mean-square error multiuser detector (RMD/MS-MMSE MUD) is considered for signal detection. Specifically, three types of RMD/MS-MMSE MUDs are proposed: Type-I. 1, Type-II. 1, and Type-I. 2 RMD/MS-MMSE MUDs. In these MUD schemes, the Type-I. 1 MUD carries out the joint detection of all the subcarrier signals using both the observations and the channel state information (CSI) of all the subcarriers. In the Type-I. 2 and Type-II. 1 RMD/MS-MMSE MUDs, the embedded MMSE-MUDs are implemented subcarrier by subcarrier independently. Furthermore, in the Type-I. 2 RMD/MS-MMSE MUD, the autocorrelation matrices used by the MMSE-MUDs are free from CSI. Explicitly, both Type-II. 1 and Type-I. 2 RMD/MS-MMSE MUDs are suitable for operation in dynamic spectrum environments. Furthermore, our simulation results show that the preceding three types of RMD/MS-MMSE MUDs are capable of making the RRNS MC/DS-CDDMA systems achieve similar error and throughput performance. Owing to the foregoing merits, the RRNS MC/DS-CDDMA employing either Type-I. 2 or Type-II. 1 RMD/MS-MMSE MUD may be considered one of the highly promising dynamic multiple-access schemes for application in CR systems.

关键词： code-division multiple access cognitive radios (CRs) dynamic multiple access (DMA) multicarrier modulation multiuser detection (MUD) redundant residue number system (RRNS) residue number system (RNS)

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Performance analysis of optical wireless indoor dual-amplitude pulse interval modulator code-division multiple-access systems

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OPTICAL ENGINEERING 2005年第8期44卷 085001-1-085001页

作者： Zhang, HT Gong, ML Wang, DS Yu, DW Cui, RZ Yan, P Chen, G Liu, Q Zhang, K Tsinghua Univ Ctr Photon & Elect State Key Lab Tribol Dept Precis Instruments Beijing 100084 Peoples R China

The performance of code-division multiple access (CDMA) as a multiple-access technique for optical wireless communications is evaluated. The information data is modulated through dual-amplitude pulse interval modulation (DAPIM). Optical orthogonal code is used as the signature sequence. The upper bound and lower bound on the exact probability of errors per slot and per packet are derived in the presence of ambient background noise. We investigate the performance characteristics for various system parameters, including the SNR of the source information bits, receiver threshold, DAPIM order, and number of users. (c) 2005 Society of Photo-Optical Instrumentation Engineers.

关键词： optical wireless communication dual-amplitude pulse interval modulation code-division multiple access optical orthogonal code packet error rate slot error rate

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Evaluation of new codes for spectral-amplitude-coding optical code-division multiple-access communication systems

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OPTICAL ENGINEERING 2004年第4期43卷 911-917页

作者： Murugesan, K Ravichandran, VC Atilim Univ Dept Elect & Elect Engn TR-06836 Ankara Turkey Anna Univ Sch Elect & Commun Engn Commun Syst Div Madras 600025 Tamil Nadu India

New classes of codes, namely extended modified prime sequence codes (EMPSC) and difference codes, both having an ideal in-phase cross-correlation (IPCC) value of one, are suggested for spectral-amplitude-coding optical code-division multiple-access communication systems. The general structure of the system is discussed with simpler encoder and decoder architectures based on fiber Bragg gratings. Since the influence of multiuser interference can be completely removed due to ideal IPCC, the performance analyses of the proposed codes have been carried out by incorporating the effects of phase-induced intensity noise (PIIN), shot noise, and thermal noise at the receiver, employing Gaussian approximation. Assuming typical system parameters, evaluation results show that with an increase in code weight, the maximum number of accommodative users in the system can be increased as well as significant improvements in bit error probability for a given number of active users. For the same code weight, the difference codes can support a greater number of simultaneous users than the other. It is found that the effects of PIIN dominate compared to shot noise and thermal noise at large powers, whereas the effects of PIIN and shot noise are highly reduced at low powers, so that thermal noise becomes a more influential limitation factor. In comparison with earlier codes, the error performance of EMPSC is similar to that of modified quadratic congruence codes, while difference codes resemble those codes developed based on Steiner systems. (C) 2004 Society of Photo-Optical Instrumentation Engineers.

关键词： code-division multiple access spectral amplitude coding modified prime sequence codes difference codes optical communications performance evaluation

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Performance analysis of slotted fiber-optic code-division multiple-access (CDMA) packet networks

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IEEE TRANSACTIONS ON COMMUNICATIONS 1997年第7期45卷 819-828页

作者： Hsu, CS Li, VOK UNIV SO CALIF INST COMMUN SCIDEPT ELECT ENGNLOS ANGELESCA 90089

This paper examines code-division multiple-access (CDMA) techniques used in slotted fiber-optic packet networks, Since the inherent properties and signal processing of the conventional communication channels are different from those of the fiber-optic channels, new code sequences must be constructed for fiber-optic applications, The goal of our research is to analyze the performance of fiber-optic CDMA packet networks using code sequences with given orthogonality properties.

关键词： code-division multiple access fiber-optic networks packet networks performance analysis

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Demonstration of two-user, 10-Gbits/s optical code-division multiple-access system implemented by using cascaded longperiod fiber gratings formed in dispersion-compensating fiber with inner-cladding structure

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OPTICAL ENGINEERING 2005年第9期44卷 090503-1-090503页

作者： Kim, SJ Eom, TJ Kim, TY Lee, BH Park, CS Tech Univ Denmark Res Ctr COM DK-2800 Lyngby Denmark Gwangju Inst Sci & Technol Adv Photon Res Inst Kwangju 500712 South Korea Gwanju Inst Sci & Technol Dept Informat & Commun Kwangju 500712 South Korea

A two-user, 10-Gbits/s optical code-division multiple-access system implemented by using cascaded long-period fiber gratings formed in a dispersion-compensating fiber (DCF) is demonstrated. Our results show that the sensitivity of cladding modes to the refractive index change on the cladding surface is greatly reduced by utilizing the inner-cladding mode of the DCF. Two pairs of encoder/decoder are constructed and the performance is evaluated by measuring bit error rate (BER). With an interferer, a BER of 1.5 X 10(-12) is measured at a received optical power of -6 dBm. (c) 2005 Society of Photo-Optical Instrumentation Engineers.

关键词： optical communications code-division multiple access long-period fiber gratings optical systems

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Photonic code-division multiple-access communications

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FIBER AND INTEGRATED OPTICS 1997年第2期16卷 129-157页

作者： Sampson, DD Pendock, GJ Griffin, RA UNIV MELBOURNE AUSTRALIAN PHOTON COOPERAT RES CTR PHOTON RES LAB DEPT ELECT & ELECT ENGN PARKVILLE VIC AUSTRALIA UCL DEPT ELECT & ELECT ENGN LONDON ENGLAND

Photonic code-division multiple access schemes have been proposed since the 1970s. Although there are many published proposals for new coding schemes, there are many less experimental verifications of these schemes, even fewer reports of successful data transmission, and no commercial systems. We attempt to explain the key factors that have led to the current state-of-the-art. In so doing, we describe the fundamental principles of matched filtering and noise in photonic CDMA schemes. We survey important developments and show how various schemes are related. We review recent experimental advances and compare the published experimental and theoretical performance for different schemes. We discuss the current major issues and likely future directions.

关键词： code-division multiple access coherence multiplexing optical communications optical networks photonics

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