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IEEE Region 10 Conference on Analog and Digital Techniques in Electrical Engineering

作者： Hashimoto, Y Fujino, Y Kuwahara, Y Shizuoka Univ Grad Sch Sci & Engn Hamamatsu Shizuoka 4328561 Japan

ISBN: (纸本)0780385608

In the W-CDMA mobile communication up-link, a method for achieving the robust beam forming by orthogonal pilot symbol sequence for the adaptive antenna of base station is proposed. Computer simulation demonstrates that channel estimation accuracy is improved, even if Long Random Sequence is not used for the spread code, and that communication capacity in the frequency selective fading environment increases.

关键词： least mean squares methods mobile radio code division multiple access radio links array signal processing channel estimation random sequences fading channels channel coding adaptive antenna arrays orthogonal coding pilot symbol MMSE adaptive antenna W-CDMA mobile communication uplink robust beamforming orthogonal pilot symbol sequence adaptive antenna base station computer simulation random sequence spread code communication capacity frequency selective fading environment increases adaptive antenna channel estimation random sequences orthogonal codes adaptive antenna arrays Code division multiple access Radio links Mobile radios array signal processing Channel coding Fading channels BASE STATION WCDMA

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SIGNATURE SEQUENCE SELECTION IN A CDMA SYSTEM WITH orthogonal coding

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 1993年第1期42卷 62-68页

作者： BOTTOMLEY, GE Ericsson-GE Mobile Communications Inc. NC USA

In code-division multiple-access (CDMA) systems, recent attention has focused on the use of orthogonal coding to provide spreading. Each signal is coded with the same orthogonal or biorthogonal code, followed by a modulo-2 addition of a unique signature sequence. The set of signature sequences used determines how much signals interfere with each other at a receiver, thus determining the performance of the system. This paper presents an analysis to determine the properties of an optimal set of signature sequences for such a system. Using a Kerdock code, a set of signature sequences is presented which optimizes performance in a direct sequence CDMA system with a) synchronous transmission, b) no multipath time dispersion, and c) orthogonal or biorthogonal Walsh-Hadamard (WH) coding as a means of spreading the information signal. For a length N binary code (N an even power of two), the set contains N/2 signature sequences. Approaches are discussed for the cases when N is an odd power of two and when more sequences are needed.

关键词： .CDMA System Selection Signature Sequence code set optimal set information signal orthogonal coding modulo addition set of signature Kerdock no multipath time dispersion odd power

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VL-Watchdog: Visible Light Spoofing Detection With Redundant orthogonal coding

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IEEE INTERNET OF THINGS JOURNAL 2022年第12期9卷 9858-9871页

作者： Chen, Jian Shu, Tao Auburn Univ Samuel Ginn Coll Engn Dept Comp Sci & Software Engn Auburn AL 36849 USA

With the rapid increase of smart devices in the Internet of Things, more and more visible light (VL) systems, e.g., VL communication (VLC) and VL sensing (VLS), are developed on the existing light fixtures to offload the current crowded spectrum, how to guarantee the authenticity of the VL signal in these systems becomes an urgent problem. This is because almost all of today's light fixtures are unprotected and can be openly accessed by almost anyone and, hence, are susceptible to spoofing attacks. As such, ensuring received VL signals are coming from the authentic transmitters (LEDs), rather than from a spoofer, is the key in ensuring the quality and correctness of the VL communication and sensing outcomes. Existing authentication methods are either not directly applicable to signal-level authentication, or have poor scalability. In this article, by exploiting the intrinsic linear superposition characteristics of VL, we propose VL-Watchdog, a scalable and always-on signal-level spoofing detection framework that is applicable to both VLC and VLS systems. VL-Watchdog is based on redundant orthogonal coding of the transmitted VL, and can be implemented as a small hardware add-on to an existing VL system. A proof-of-concept testbed was developed to verify the feasibility of VL-Watchdog. The effectiveness of the proposed framework was validated through extensive numerical evaluations against a comprehensive set of factors.

关键词： Light emitting diodes Internet of Things Visible light communication Radio frequency Encoding Bandwidth Optical filters Internet of Things (IoT) multilink visible light communication (VLC) orthogonal coding spoofing detection VLC and visible light sensing (VLS)

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Two dimensional equalization scheme of orthogonal coding multi-carrier CDMA

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 1998年第6期E81A卷 1079-1088页

作者： Watanabe, S Sato, T Sengoku, M Abe, T Niigata Inst Technol Kashiwazaki 9451195 Japan Niigata Univ Fac Engn Niigata 9502181 Japan

This paper describes two dimensional (2D) equalization scheme of orthogonal coding multi-carrier CDMA for reverse link of mobile communication systems. The purpose of the 2D equalization is the reduction of Multiple Access Interference (MAI) which is caused by the random access and the different propagation path from each mobile station. The orthogonal coding multi-carrier CDMA multiplexes all mobile stations' data by Code Division Multiplexing (CDM). The 2D coding scheme spreads a preamble signal at time (in subchannel signals) and frequency (between subchannel signals) domains. The 2D decoding scheme estimates transmission delay time and instantaneous fading frequency from preamble signal for individual mobile stations and compensate the received data using these estimation values to reduce MAI.

关键词： MAI 2D equalization orthogonal coding multi-carrier CDMA

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IMPROVEMENT OF NONCOHERENT orthogonal coding BY TIME OVERLAPPING

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IEE PROCEEDINGS-COMMUNICATIONS 1994年第5期141卷 309-311页

作者： RAPHAELI, D Dept. of Electr. Eng. California Inst. of Technol. Pasadena USA

A simple way to increase the performance of noncoherent orthogonal coding is suggested. The idea is to overlap the transmitted symbols in time using an appropriate set of symbols. The best upper bound of the possible performance improvement in terms of E(b)/N(o) when transmitting over the AWGN channel is proven to be M/(M - 1). An example of a set of orthogonal symbols which can be overlapped to achieve this bound is the Walsh functions. The theory is a generalisation of the relation which exists between binary FSK and differential PSK for M-ary orthogonal noncoherent modulation.

关键词： orthogonal coding

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Encoding and Decoding Schemes in Communication Systems using orthogonal coding for Noise Immunity's Increase

Encoding and Decoding Schemes in Communication Systems using...

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Wave Electronics and its Application in Information and Telecommunication Systems (WECONF)

作者： Rabin, A., V St Petersburg State Univ Aerosp Instrumentat St Petersburg Russia

ISBN: (纸本)9781728122885

The objective of the paper is a development and a research of the offered by the author orthogonal coding as a way of noise immunity's increase using the example of the information communication systems with a phase-shift keying. It is shown, that the orthogonal coding allows to provide the required quality of communication with a smaller energy cost. The energy gain in signal-to-noise ratio is provided by more effective use of energy of transmitted signals with the fixed code rate, without increase in complexity and cost of transmitting/receiving schemes. The orthogonal coding is an analogue of convolutional coding over the rational numbers' field. Properties of orthogonality of proposed codes allow to strengthen significance of useful signal with simultaneous weakening of influence of AWGN. Technical realization of orthogonal coding is characterized by low complexity: on each step a decoding process is reduced to calculation of several dot products and comparison with the fixed (zero, in this case) threshold. For this reason, the offered way of coding and design of receiving and transmitting schemes can be implemented in various communication systems.

关键词： noiseless coding orthogonal coding phase-shift keying spectral efficiency encoding schemes decoding schemes

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Joint orthogonal coding and Modulation Scheme for Soft Information in Bi-Directional Networks

Joint Orthogonal Coding and Modulation Scheme for Soft Infor...

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7th International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM)

作者： Wei, Sha Li, Jun Su, Hang Shanghai Jiao Tong Univ Dept Elect Engn Shanghai 200240 Peoples R China Univ New South Wales Sch Elect Engn & Telecommun Sydney NSW 2052 Australia

ISBN: (纸本)9781424462520

In this paper, the authors propose a confidence-based joint orthogonal coding and modulation algorithm for soft information cooperation in the time-division broadcast bidirectional relaying networks. We first compute the log-likelihood ratio (LLR) of the received signals at relay nodes in the first two time slots, then derive the probability distribution of the scaled LLR. Inspired by the space-time coding, the quadrature components of the orthogonal coded signal is composed by the soft information from two terminals. Later, to reduce the computation complexity of the traditional cluster partition, we quantize the orthogonal coded signal to the lattice points, and propose a confidence-based cluster partition algorithm which is adaptive to the modulation scheme and bandwidth limitation. Moreover, we derive the bit error rate (BER) expression for the proposed algorithm. From the simulation results, it is shown that with multiple relays assisting the transmission, the proposed scheme is outperforms AF, DF and CF strategies in BER metric;while for single relay case, the BER performance of the proposed scheme is comparable with AF, DF and CF strategies.

关键词： Soft information bi-directional relay lattice quantization confidence-based partition orthogonal coding

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Hierarchical coding for sequential task events in the monkey prefrontal cortex

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PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2008年第33期105卷 11969-11974页

作者： Sigala, Natasha Kusunoki, Makoto Nimmo-Smith, Ian Gaffan, David Duncan, John Cognit & Brain Sci Unit MRC Cambridge CB2 7EF England Univ Oxford Dept Expt Psychol Oxford OX1 3UD England

The frontal lobes play a key role in sequential organization of behavior. Little is known, however, of the way frontal neurons code successive phases of a structured task plan. Using correlational analysis, we asked how a population of frontal cells represents the multiple events of a complex sequential task. Monkeys performed a conventional cue-target association task, with distinct cue, delay, and target phases. Across the population of recorded cells, we examined patterns of activity for different task phases, and in the same phase, for different stimulus objects. The results show hierarchical representation of task events. For different task phases, there were different, approximately orthogonal patterns of activity across the population. of neurons. Modulations of each basic pattern encoded stimulus information within each phase. By orthogonal coding, the frontal lobe may control transitions between the discrete steps of a mental program;by correlated coding within each step, similar operations may be applied to different stimulus content.

关键词： correlated coding orthogonal coding pair associative task sequence representation

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Signal separation coding for robust depth imaging based on structured light

Signal separation coding for robust depth imaging based on s...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Lee, S Choi, J Kim, D Na, J Oh, S Sungkyunkwan Univ Intelligent Syst Res Ctr Suwon 440746 South Korea

ISBN: (纸本)078038914X

This paper presents an original approach to coding the light patterns for robust depth imaging based on structured light. We have discovered that the degradation of precision and robustness, seen in most conventional approaches to structured light, comes mainly from the overlapping of multiple codes in the signal received at a camera pixel, where the overlapped codes are from the neighbouring and/or, even, distant pixels of the projecting mirror array. Considering the criticality of separating the overlapped codes to precision and robustness, we propose a novel signal separation code, referred to here as "Hierarchical orthogonal Code (HOC)," for depth imaging. HOC provides not only the separation of overlapped codes, but also a robust decision on pixel correspondence with error correction based on a contextual likelihood among the sets of separated codes from neighbouring camera pixels. The experimental results have shown that the proposed HOC significantly enhances the robustness and precision in depth imaging, compared to the best known conventional approaches. The proposed approach opens a greater feasibility of applying structured light based depth imaging to a 3D modelling of cluttered workspace for home service robots.

关键词： structured light depth imaging signal separation orthogonal coding

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Research on passive ranging technology based on wave front coding

Research on passive ranging technology based on wave front c...

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Conference on AOPC - Optical Sensing and Imaging Technology

作者： Jiao, Mi Hui, Zhao Chinese Acad Sci Xian Inst Opt & Precis Mech Xian Peoples R China Univ Chinese Acad Sci Beijing Peoples R China

ISBN: (纸本)9781510650060;9781510650053

Optical passive ranging is based on the light signal radiated by the object itself. The application of wave front coding technology to passive ranging systems simplifies the system structure and improves the ranging accuracy to a large extent. In this paper, the orthogonal coding passive ranging system with the cosine foul' of the mask function is investigated, and the optical transfer function and the light intensity distribution at the distances of 1m-4m and 1km-5km are simulated by numerical simulation to verify the rationality of the orthogonal coding ranging system, and the measurement error is about. +/- 0.1m.

关键词： Optical passive range orthogonal coding Optical transfer function Mask function

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