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13th Canadian Workshop on Information Theory (CWIT)

作者： Niu, Mingbo Cheng, Julian Holzman, Jonathan F. Univ British Columbia Sch Engn Kelowna BC V1V 1V7 Canada

ISBN: (纸本)9781479906345

space-time codes are of great interest for wireless communication systems as they can be used to improve the system performance. For optical wireless communications using coherent detection, atmospheric channels can induce fading as well as phase noise to degrade wireless link performance. In this paper, a space-time coded communication system is studied for a wireless optical link using coherent detection over atmospheric turbulence channels. An Alamouti-type space-time coded system structure is proposed when both turbulence-induced fading and phase noise from the channel and lasers are present. The error rate performance is analyzed for the proposed scheme over a wide range of turbulence conditions. Closed-form error rate expressions are derived for such systems for fast performance evaluation. In numerical case studies, the usefulness of the proposed optical wireless space-time coded system is demonstrated by a comparison to a single-input single-output optical wireless communication system.

关键词： Atmospheric turbulence coherent detection optical wireless systems space-time coding

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space-time coding Implementation with a Software-Defined Radio Testbed 8

Space-Time Coding Implementation with a Software-Defined Rad...

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8th IEEE Annual Computing and Communication Workshop and Conference (CCWC)

作者： Shaha, Apurv Nguyen, Duy H. N. San Diego State Univ Dept Elect & Comp Engn San Diego CA 92182 USA

ISBN: (纸本)9781538646496

Multiple Input Multiple Output (MIMO) uses the multiple antennas at transmitter and receiver to improve the spectral efficiency of the communication system. In this paper, an overview of implementing MIMO is described while meeting the challenges of current communication systems such as channel estimation, baseband synchronization, and local oscillator synchronization. The paper begins with the system model designed at both transmitter and receiver using the space-time coding. Developed algorithms are also discussed for improving the throughput and spectral efficiency of the designed system. We particularly focus on finding the probability of bit error rate with the variation on the TX-RX distance and comparing with other MIMO implementations. Finally, we analyze the performance of the received signals based on several metrics such as quadrature skew, IQ gain imbalance, modulation error ratio, phase offset, frequency drift, frequency offset, phase error in peak and magnitude error in peak before and after using space-time wireless coding with the 16-QAM modulation scheme. All the algorithms designed are implemented using the Universal Software Radio Peripheral (USRP) testbed using Software Defined Radio (SDR) platform with LabVIEW software.

关键词： MIMO space-time coding 5G SDR USRP QAM LabVIEW channel estimation spectral efficiency synchronization testbed implementation

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Concatenated space-time coding with two transmit antennas

Concatenated space-time coding with two transmit antennas

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4th International ITG Conference on Source and Channel coding

作者： Schulze, Henrik Univ. of Applied Sciences Meschede D-59872 Meschede Germany

In this paper, we investigate the concetanation of Alamouti's 2-antenna space-time coding scheme with standard outer error-correcting codes. By introducing a proper matrix description, the channel can be visualized as a 4-dimensional rotation of a generalized phasor (given by the pair of transmit symbols), followed by the attenuation given by the composed fading amplitude. This interpretation makes it easy to understand that this 2-transmit (TX) antenna scheme is completely equivalent to a 2-receive (RX) antenna setup with maximum ratio combining (MRC). Analytical formulas for pair error probabilities will be derived for the time/frequency flat fading and for the ideally interleaved Rayleigh fading channel as well as for the correlated fading channel. As a practical example, we study how the performance of a Walsh-Hadamard coded multi-carrier (MC-) CDMA system depends of the correlation bandwidth of the channel and the number of RX and TX antennas.

关键词： Channel coding Diversity Fading channels space-time coding Wireless communications

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High-Precision Terahertz Beam Steering via space-time coding HEMT-Metasurfaces

High-Precision Terahertz Beam Steering via Space-Time Coding...

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2023 Cross Strait Radio Science and Wireless Technology Conference, CSRSWTC 2023

作者： Nie, Xiaolei Lan, Feng Zhang, Yaxin Yang, Ziqiang Wang, Luyang Song, Tianyang Yang, Munan School of Electronic Science and Engineering Sichuan THz Communication Technology Engineering Research Center University of Electronic Science and Technology of China Chengdu China Huzhou China

ISBN: (纸本)9798350358971

Terahertz space-time coding metasurfaces (TSTCM) exhibit exquisite beam reconstruction capabilities in microwave and quasi-optical bands and have broad application prospects in wireless communications, reprogrammable holographic imaging, and direct transmission of digital information. Fourier analysis of periodic modulated signals in the time domain shows that the time delay and duty ratio independently control the incident wave. Herein, we propose an equivalent multi-bit space-time coding metasurface which based on high electron mobility transistors (HEMTs), implemented positive and negative first-order harmonic beam scanning in farfield simulation. We demonstrate the scanning result with a scanning range of ±80° and a step accuracy of 0.5°, which matched well with the designed device from 0.16THz to 0.23THz. © 2023 IEEE.

关键词： beam scanning HEMTs metasurface space-time coding

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High-Resolution and Wide-Swath SAR Imaging with space-time coding Array

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REMOTE SENSING 2023年第9期15卷 2465-2465页

作者： Yu, Kun Zhu, Shengqi Lan, Lan Yang, Biao Xidian Univ Natl Key Lab Radar Signal Proc Xian 710071 Peoples R China

To achieve high-resolution and wide-swath (HRWS) synthetic aperture radar (SAR) images, this paper focuses on resolving the problem of separating range-ambiguous echoes with the space-time coding (STC) array. At the modeling stage, the transmit elements and pulses of the STC array are configured with time delay and phase coding modulation, which introduces extra degrees of freedom (DOFs) in the transmit domain. To separate the echoes corresponding to different range-ambiguity regions, the equivalent transmit beamforming is performed in the two-dimensional space-frequency domain. Moreover, in order to compensate for the loss of range resolution during the beamforming progress, the frequency splicing method is proposed. At the analysis stage, the distributed target simulation is provided to demonstrate the effectiveness of obtaining HRWS SAR images in the STC radar. Additionally, the performance of resolving range ambiguity is compared with the traditional radar in terms of the range-ambiguity-to-signal ratio (RASR).

关键词： advance radar techniques space-time coding transmit beamforming synthetic aperture radar range ambiguity high resolution and wide swath

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Censored distributed space-time coding for wireless sensor networks

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EURASIP JOURNAL ON ADVANCES IN SIGNAL PROCESSING 2008年第unknown期2008卷 127689-1-127689-9-0页

作者： Yiu, S. Schober, R. Univ British Columbia Dept Elect & Comp Engn Vancouver BC V6T 1Z4 Canada

We consider the application of distributed space-time coding in wireless sensor networks (WSNs). In particular, sensors use a common noncoherent distributed space-time block code (DSTBC) to forward their local decisions to the fusion center (FC) which makes the final decision. We show that the performance of distributed space-time coding is negatively affected by erroneous sensor decisions caused by observation noise. To overcome this problem of error propagation, we introduce censored distributed space-time coding where only reliable decisions are forwarded to the FC. The optimum noncoherent maximum-likelihood and a low-complexity, suboptimum generalized likelihood ratio test (GLRT) FC decision rules are derived and the performance of the GLRT decision rule is analyzed. Based on this performance analysis we derive a gradient algorithm for optimization of the local decision/censoring threshold. Numerical and simulation results show the effectiveness of the proposed censoring scheme making distributed space-time coding a prime candidate for signaling in WSNs. Copyright (C) 2008.

关键词： time coding algorithm optimization noncoherent Error propagation decision rule Distribute differential space-time coding space-time coding

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Simplified Alamouti-Type space-time coding for Image Sensor Communication Using Rotary LED Transmitter

IEEE PHOTONICS JOURNAL

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IEEE PHOTONICS JOURNAL 2022年第1期14卷 1页

作者： Tang, Zhengqiang Arai, Shintaro Yamazato, Takaya Nagoya Univ Nagoya Aichi 4648603 Japan Okayama Univ Sci Okayama 7000005 Japan

This study proposes a simplified Alamouti-type space-time coding (STC), improving the performance of image sensor communication (ISC) using a rotary LED transmitter. The rotary LED transmitter was developed to increase the data rate of ISC using afterimages of LED lights. The transmitter simultaneously causes the LEDs to blink and rotates them around a vertical axis. Owing to the movement of the blinking LEDs that occurs within the exposure time of the camera, multiple blinking states are captured as afterimages, thus increasing the amount of information that can be received per image. However, with increasing communication distance, the size of the LED light captured on the image sensor decreases. In this case, it is difficult to distinguish each LED blinking state, leading to a degradation of the demodulation performance. To overcome this problem, the proposed STC encodes adjacent angular afterimages as symbol pairs and transmits these symbol pairs using two symbol times. In addition, we simplified the data decoding process by using normalized LED luminance values. We evaluate the demodulation performance of the proposed method through experiments. Compared with conventional coding methods, the proposed STC requires no channel estimation and significantly improves the demodulation performance.

关键词： Light emitting diodes Cameras Optical transmitters Demodulation Decoding Interference Image sensors Visible light communication image sensor communication rotary LED transmitter afterimages space-time coding

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A multi-frame space-time coding method for the phase-coded signal in MIMO radars

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DIGITAL SIGNAL PROCESSING 2023年 133卷

作者： Zhang, Cheng Zhang, Gong Nanjing Univ Aeronaut & Astronaut Coll Elect & Informat Engn Key Lab Radar Imaging & Microwave Photon Minist Educ Nanjing 211100 Peoples R China Nanjing Univ Aeronaut & Astronaut Nanjing 210016 Peoples R China

Code-division multiplexing (CDM) has become the focus of designing orthogonal waveforms of multiple -input multiple-output (MIMO) radars as it occupies fewer resources than time-division multiplexing (TDM) and frequency-division multiplexing (FDM). As one of the standard CDM waveforms, conventional inter-pulse phase-coded waveform possesses non-ideal diversity performance. That is, the orthogonality of the signals will reach the threshold after the codes extend to a certain length. To circumvent the coding restrictions, space-time coding (STC) makes use of spatial resources. This paper proposes a multi-frame STC method to improve the orthogonality among waveforms. Specifically, we first design the orthogonal transmitted signals and corresponding matched filters for MIMO radars. Then the signal expressions and the radar ambiguity function (AF) are deduced to verify the proposed method theoretically. Compared with conventional STC, such a method can save half of the time domain resources and make the most of coding resources. Furthermore, the output signal-to-noise ratio (SNR) is well improved as the proposed method effectively suppresses the cross-correlation energy of the waveform. The proposed multi-frame STC waveform can be easily implemented in practical radar applications because of its constant waveform amplitude. The theoretical analysis and simulation results demonstrate the effectiveness of the method.(c) 2022 Elsevier Inc. All rights reserved.

关键词： MIMO radar Phase-coded space-time coding Multi -frame Ambiguity function

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Digital watermarking algorithm based on space-time coding

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Procedia Engineering 2010年 7卷 416-421页

作者： Fan Zhang Xinhong Zhang Rui Li College of Computer and Information Engineering Henan University Kaifeng 475001 China Institute of Image Processing and Pattern Recognition Henan University Kaifeng 475001 China

Theories of spread spectrum communications, channel coding, capacity analysis techniques have been widely applied in digital watermarking research. In recent years, communication theory has made an important technological breakthrough. The next generation mobile communication systems (4G) is far exceeding the capacity needs of the traditional Shannon channel capacity limit, and this need promotes the rapid development of multiple-input multiple-output (MIMO) technology. The combination of space-time coding and MIMO technology will breakthrough the capacity limit of single-input single-output (SISO) channel. In this paper, the digital image watermarking system is extended from SISO to MIMO systems based on space-time coding and MIMO communication theory. The new watermarking algorithm is designed in the new framework of space-time coding and MIMO-based communication theory. The watermark capacity and the detection error rate also are further studied under the conditions of different space-time coding. These studies will provide a new idea for the design of new digital watermarking algorithm.

关键词： Digital image processing Digital watermarking MIMO space-time coding

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Robust Signal Processing for the space-time coding Applications

Robust Signal Processing for the Space-Time Coding Applicati...

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IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus)

作者： Binh Dang Zhukov, Vladimir A. ITMO Univ Fac Control Syst & Robot St Petersburg Russia St Petersburg State Marine Tech Univ Dept Marine Elect St Petersburg Russia

The principle of space-time block coding is considered. The main problems of building MIMO radar systems are described. Encoding methods for antennas with a variety of active elements are proposed. An assessment of th... 详细信息

ISBN: (纸本)9781728103396

关键词： adaptive robust signal processing space-time coding active radar communication systems

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