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space-time-Doppler block coding for correlated time-selective fading channels

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2005年第6期53卷 2167-2181页

作者： Ma, XL Leus, G Giannakis, GB Auburn Univ Dept Elect & Comp Engn Auburn AL 36849 USA Delft Univ Technol Fac Elect Engn Math & Comp Sci NL-2628 CD Delft Netherlands Univ Minnesota Dept Elect & Comp Engn Minneapolis MN 55455 USA

Coping with time-selective fading channels is challenging but also rewarding, especially with multiantenna systems, where joint space-Doppler diversity and coding gains can be collected to enhance performance of wireless mobile links. These gains have not been quantified, and space-time coded systems maximizing joint space-Doppler benefits have not been designed. Based on a parsimonious basis expansion model for the underiving time-selective (and possibly correlated) channels, we quantify these gains in closed form. Furthermore, we develop space-time-Doppler coded systems that guarantee the maximum possible space-Doppler diversity, along with the largest coding gains within all linearly coded systems. Our three novel designs exploit knowledge of the maximum Doppler spread, and each offers a uniquely desirable tradeoff, including high spectral efficiency, low decoding complexity, and high performance. Our analytical results are confirmed by simulations and reveal the relative of merits of our three designs in comparison with an existing approach.

关键词： basis expansion channel model diversity fading phase sweeping space-time coding time-varying channel

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Nonuniform unitary space-time codes for layered source coding

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2004年第3期3卷 958-965页

作者： Larsson, EG Wong, WH Univ Florida Dept Elect & Comp Engn Gainesville FL 32611 USA

We discuss new space-time codes tailored to point-to-multipoint, or broadcast, communications using layered source coding. Our codes can be encoded (and decoded) differentially, and they are based entirely on phase-shift keying. We discuss design criteria for the codes, and the design of optimal and suboptimal receiver structures. We also discuss the relation between our codes and a differentially encoded Alamouti code. Finally, we illustrate how our codes can be used to improve the throughput of a broadcasting network.

关键词： differential encoding diversity maximum likelihood (ML) nonuniform constellations phase-shift keying (PSK) space-time coding

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space-time-frequency (STF) coding for MIMO-OFDM systems

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IEEE COMMUNICATIONS LETTERS 2002年第9期6卷 370-372页

作者： Molisch, AF Win, MZ Winters, JH AT&T Labs Res Wireless Syst Res Dept Middletown NJ 07748 USA

We consider the capacity of multiple-input-multiple-output (MIMO) systems that use OFDM as the modulation format. We point out a basic equivalence between antennas and OFDM-tones. This similarity immediately allows us to essentially reuse all space-time codes designed for flat-fading channels in MIMO-OFDM systems operating in frequency-selective channels. An optimum code would thus code across all antennas and tones (as well as time) simultaneously. Since this can become very complex, we propose a method for grouping antennas and codes in such a way that the inherent diversity is retained, while the complexity is greatly reduced. Capacity computations between the full-complexity and the reduced-complexity systems illustrate this tradeoff.

关键词： MIMO OFDM space-time coding

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time-Domain Repetition coding for MISO Transmission over Free-space Optical Channel

Time-Domain Repetition Coding for MISO Transmission over Fre...

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IEEE 78th Vehicular Technology Conference (VTC Fall)

作者： Kim, Jeongchan Han, Youngnam Lee, Seung-Hwan Korea Adv Inst Sci & Technol Dept Elect Engn & Comp Sci Taejon 305701 South Korea Elect & Telecommun Res Inst Integrated Wireless Res Sect Daejeon South Korea

ISBN: (纸本)9781467361873

In this paper, we suggest a multiple-input/singleoutput (MISO) transmission technique for free-space optical links with intensity modulation and direct detection. Specifically, time-domain repetition coding is investigated over slow and weak turbulence fading channels, where we suggest a set of efficient codewords for MISO transmission with time-domain repetition coding. The proposed approach increases signal to noise ratio (SNR) most effectively by allocating total radiated power fully into only one transmit aperture for a single bit period with post-processing followed by equal gain combining at a receiver. We evaluate instantaneous electrical SNR and conditional bit error rate (BER) numerically. Numerical results show that as the number of transmit apertures increases the BER performance gap increases, which reveals its outperformance over other schemes not only in weak turbulence channels but also in weak turbulence channel with misalignment problem.

关键词： Multiple-input/single-output (MISO) systems free-space optical communication spatial diversity space-time coding time diversity

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Decoupling Strategy of Metasurface to Realize Independent Sensing and Wave Manipulations at the Same time

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ADVANCED MATERIALS 2025年第0期 e2500266页

作者： Zhou, Qun Yan Wu, Lijie Li, Hui Dong Wang, Jia Chen Wang, Siran Luo, Jiang Liu, Shuo Ma, Jitong Dai, Jun Yan Cheng, Qiang Cui, Tie Jun Southeast Univ State Key Lab Millimeter Waves Nanjing 210096 Peoples R China City Univ Hong Kong State Key Lab Terahertz & Millimeter Waves Hong Kong 999077 Peoples R China Hangzhou Dianzi Univ Sch Elect & Informat Hangzhou 310018 Peoples R China Southeast Univ Inst Electromagnet Space Nanjing 210096 Peoples R China Southeast Univ Frontiers Sci Ctr Mobile Informat Commun & Secur Nanjing 210096 Peoples R China Dalian Maritime Univ Sch Informat Sci & Technol Dalian 116000 Peoples R China Suzhou Lab Suzhou 215000 Peoples R China

In recent years, integrating electromagnetic (EM) sensing and wave manipulation has become crucial for future wireless developments, significantly enhancing the application performance by acquiring complex environmental information and optimizing the distribution of EM resources. Metasurface offers unprecedented control over sensing and wave manipulation, yet a conflict arises in achieving both simultaneously. To solve the problem, a decoupling strategy is proposed to simultaneously realize sensing and wave manipulation using a space-time-coding digital metasurface (STCDM) without integrating any sensors. A space-time-coding matrix is constructed by allocating the reflectivity of all meta- atoms across the space-time dimensions, enabling arbitrary manipulation of EM waves while simultaneously acquiring the sensing information at the incident frequency from metasurface. Excellent accuracy of direction-of-arrival estimation and wave manipulation confirms the decoupling method. An adaptive STCDM system is built up to validate the strategy in wireless communications. The measured results show that the adaptive STCDM enables independent sensing and wireless communications at the same time for targets located at different positions without integrating any sensors. The proposed method may find potential applications in wireless communication, radar, and Internet of Things systems.

关键词： Integrating sensing and wave manipulation metasurface space-time coding wave manipulation wireless sensing

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Multi-pair Device-to-Device Communications with space-time Analog Network coding

Multi-pair Device-to-Device Communications with Space-Time A...

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IEEE Wireless Communications and Networking Conference (WCNC)

作者： Wei, Lili Wu, Geng Hu, Rose Qingyang Intel Corp Santa Clara CA 95051 USA Utah State Univ Logan UT 84322 USA

ISBN: (纸本)9781479984060

Device-to-device (D2D) communication, which enables a user equipment to communicate with another nearby UE directly over a D2D link without going through the central base station (BS), have attracted great research interests for future applications on high data rates and spectral efficiency. In this work, we investigate multi-pair D2D communications with a multiple antenna relay under three possible schemes: (i) Direct D2D transmission;(ii) Multi-hop D2D with analog network coding where the relay will help multi-pair D2D transmission by amplify-and-forwarding mixed received signals;(iii) Multi-hop D2D with space time analog network coding where the relay will help multi-pair D2D transmissions by amplify-and-forwarding mixed received signals together with space time coding techniques. Specifically, three pairs of D2D communications with a two-antenna relay are modeled and space-time analog network coding based on Alamouti scheme is applied. We compare the D2D sum rate and bit error rate performance of different schemes under different channel scenarios.

关键词： Multicast device-to-device communications net-work coding cooperative relay space-time coding

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Angle and Distance Discrimination by Utilizing Frequency Conversion Capability of STC-IRS for Covert Communications

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IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY 2025年 20卷 1503-1518页

作者： Wang, Manlin Yao, Yao Ding, Haiyang Shao, Shihai Xia, Bin Wang, Jiangzhou Shanghai Jiao Tong Univ SJTU Dept Elect Engn Shanghai 200240 Peoples R China Natl Univ Def Technol Sch Informat & Commun Wuhan 430010 Peoples R China Univ Elect Sci & Technol China Natl Key Lab Sci & Technol Commun Chengdu 611731 Peoples R China Univ Kent Sch Engn Canterbury CT2 7NT England

Covert communication is an important approach to ensure information security by hiding the transmission behavior. space-domain-coding intelligent reflecting surface (SDC-IRS) can adjust the phase of the reflection signal for passive beamforming in angle domains, which is widely employed in covert communications. However, the gains by SDC-IRS vanish when the warder is proximal to the receiver in angle domains. To overcome this limitation, in this paper, the space-time-coding IRS (STC-IRS) is considered, which can adjust both the phase and the frequency of the reflection signal for passive beamforming in angle-distance domains. Specifically, system performance under STC-IRS and SDC-IRS is compared, revealing the essence that angle and distance discrimination for the receiver is achieved with STC-IRS. Further, to fully exploit STC-IRS, optimization problems are formulated to maximize the covert rate in both line-of-sight scenarios and Rician fading scenarios. To solve the above problems, penalty-based algorithms are proposed where the transmit power, the phase shift and the frequency shift at STC-IRS are optimized jointly with majorization-minimization and block successive upper bound minimization techniques. Considering more general and adverse cases, the proposed algorithms are also extended to the scenario with multiple warders. Simulation results demonstrate the superiority of the proposed scheme compared with other benchmarks. Especially, when the warder and the receiver overlap in angle domains, covert rates with STC-IRS exceed 3 bps by distance domain discrimination, whereas covert rates with SDC-IRS are less than 0.01 bps.

关键词： Receivers Array signal processing Encoding System performance Rician channels Optimization Performance gain Band-pass filters Graphical models Distribution functions Covert communication space-time coding intelligent reflecting surface phase and frequency optimization

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space-time Analog Network coding for Multiple Access Relay Channels

Space-Time Analog Network Coding for Multiple Access Relay C...

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IEEE Wireless Communications and Networking Conference (WCNC)

作者： Wei, Lili Chen, Wen Shanghai Jiao Tong Univ Dept Elect Engn Shanghai 200030 Peoples R China

ISBN: (纸本)9781467359399;9781467359382

Network coding is a paradigm for modern communication networks by allowing intermediate nodes to mix messages received from multiple sources. Recently, space-time analog network coding (STANC) has been proposed for non-regenerative multi-way relaying, where multiple nodes are exchanging information through the multi-antenna relay without direct links. In this paper, we investigate STANC in multiple-access relay channels, where multiple nodes communicate to a common destination through a multi-antenna relay with direct links. We discuss several different possible schemes including STANC with Alamouti scheme under three time slots constraints and compare the sum rate and error rate performance.

关键词： multiple access relay channel analog network coding cooperative space-time coding

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Wireless Communication Techniques for Improved Detection Fidelity in Microfluidic Impedance Cytometry Using space-time Coded Electrodes

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IEEE SENSORS JOURNAL 2025年第2期25卷 2877-2885页

作者： Tayyab, Muhammad Javanmard, Mehdi Rutgers State Univ Piscataway NJ 08901 USA

Microfluidic flow cytometry may be used to provide important knowledge about the characteristics of microparticles, including cell size, intracellular organelles, and DNA damage response. Since there is so much study in this field, several strategies have been used to improve the system's effectiveness in a variety of areas, including sample preparation, sensing modalities, and data analysis. Due to the simplicity with which electrical components may be downsized, reduced cost, portability, and simplicity of the system, impedance-based detection offers an inherent benefit over various sensing modalities. Although electrical-based cytometry systems have a number of benefits over their optical equivalents, some problems still need to be resolved before standalone point-of-care (POC) solutions can be achieved. False peak counts caused by spurious interference, which can taint the accurate cytometry counts, are one of the key issues with electrical-based systems. In this article, we introduce a novel algorithm for error correction employing space-time coded electrodes as a first step toward a viable solution. Using our novel symbol-combining approach, we are able to increase the signal detection fidelity through an improvement in the signal-to-noise ratio (SNR) of three times compared to simple thresholding. Based on the increased SNR, we present a smart thresholding technique to increase signal fidelity and reduce the effects of spurious peaks and noise.

关键词： Electrodes Sensors Microfluidics Encoding Transmitting antennas Codes Impedance Symbols space-time codes Optical flow Biosensors impedance spectroscopy space-time coding wireless communications

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space-time Analog Network coding for Multiple Access Relay Channels

Space-Time Analog Network Coding for Multiple Access Relay C...

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IEEE Wireless Communications And Networking Conference

作者： Lili Wei Wen Chen Department of Electronic Engineering Shanghai Jiao Tong University China

ISBN: (纸本)9781467359382

关键词： multiple access relay channel analog network coding cooperative space-time coding

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