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MIMO Radar Range-Angular-Doppler Sidelobe Suppression Using Random Space-time coding

IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2014年第3期50卷 2047-2060页

作者： Zhou, Shenghua Liu, Hongwei Wang, Xu Cao, Yunhe Xidian Univ Natl Lab Radar Signal Proc Xian 710071 Shannxi Peoples R China

To further reduce the sidelobe level of waveforms for colocated multiple-input multiple-output (MIMO) radar, a random space-time coding (STC) method is proposed, which modulates prescribed waveforms at each transmission by a random permutation matrix multiplied by a random diagonal phase matrix. With the random modulation, sidelobes at different pulse repetition periods cannot be coherently accumulated, and then the overall sidelobe level drops significantly after coherent accumulation, as verified by numerical results.

关键词： sidelobe reduction time coding waveforms Random modulation side lobe level permutation matrix Random MIMO radar space-time coding

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Hybrid time-Frequency Coded Photonic Crystal-based Chipless Retroreflective Tag Landmarks 14

Hybrid Time-Frequency Coded Photonic Crystal-based Chipless ...

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14th German Microwave Conference (GeMiC)

作者： Neuder, Robin Sanchez-Pastor, Jesus Schuessler, Martin Jakoby, Rolf Jimenez-Saez, Alejandro Tech Univ Darmstadt Inst Microwave Engn & Photon Darmstadt Germany

ISBN: (纸本)9783982039725

This paper studies the implementation of a hybrid time-frequency modulation scheme in the chipless retroreflective tag landmarks of a mm-Wave indoor self-localization system. The fully-passive implementation of the modulation scheme is demonstrated with high-Q cavities working at 78 GHz for frequency coding and different time delays induced by the length of the transmission line for time coding. Both modulations operate within the same bandwidth and are integrated in a monolithic dielectric slab using a Photonic Crystal (PhC) periodic structure. Three hybrid coded tag landmarks manufactured in Rogers 6010.2LM are evaluated in measurements at 60 cm. While the cavity response is distinctively traceable in frequency domain, time domain analysis shows that implemented delays are correctly read out by the reader with a discrepancy of less than 8% compared with simulations, providing a proof of concept for hybrid time-frequency coding in PhC-based tag landmarks.

关键词： photonic crystals radio frequency identification high-Q resonant cavities time coding hybrid coding

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Wireless Communication Based on Information Metasurfaces

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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 2021年第3期69卷 1493-1510页

作者： Dai, Jun Yan Tang, Wankai Chen, Ming Zheng Chan, Chi Hou Cheng, Qiang Jin, Shi 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 Southeast Univ Natl Mobile Commun Res Lab Nanjing 210096 Peoples R China

Metasurface has great capabilities in tailoring the electromagnetic (EM) waves in a controllable way owing to the carefully designed and arranged subwavelength meta-atoms. In this review paper, the digital version of metasurface, information metasurface (IM), is systematically introduced with its application in wireless communications. IM extends the research scope of metasurface from physics to the information perspective, in which the meta-atoms are represented by using digital codes "0" and "1" to characterize the EM responses. It can achieve programmable controls of EM waves in real time by integrating with the field-programmable gate array (FPGA). On the other hand, the digital coding strategy bridges the physical world and digital world, and further make the metasurface realize direct information processing. With the outstanding advantages, IMs have shown great potentials to bring revolutionary applications in wireless communications. In this article, the basic concepts and principles of IMs and their programmable features are presented first. Then it focuses on the IM-based new architecture transmitters, as well as the IM-integrated wireless networks in more detail. Finally, the current progress and the future directions of IMs in the wireless communications are respectively summarized.

关键词： Digital coding information metasurface (IM) metasurface new transmitter architecture smart wireless networks time coding wireless communications

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Achieving High Reliability in Aerial-Terrestrial Networks: Opportunistic Space-time coding

Achieving High Reliability in Aerial-Terrestrial Networks: O...

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European Conference on Networks and Communications (EuCNC)

作者： Jiang, Wei Cao, Hanwen Wiemeler, Michael Kaiser, Thomas Univ Duisburg Essen UDE Inst Digital Signal Proc DSV D-47057 Duisburg Germany

ISBN: (纸本)9781479952809

To rapidly deploy a communication network in the aftermath of disaster or emergency event, an Aerial-Terrestrial architecture integrating aerial base stations mounted on the balloons has been investigated in EU FP7 ABSOLUTE project. Since the signal coverage provided by aerial base stations is patchy and unstable, the opportunistic relaying is applied to increase the link reliability and the system robustness. However, the performance of relay selection drastically degrades due to the outdated Channel State Information (CSI) from the feedback delay over the Aerial-to-Terrestrial radio channels. In this paper, therefore, we present a novel method named opportunistic space-time coding (OSTC) to combat the outdated CSI. The link reliability in terms of outage probability is evaluated using both Rayleigh channels and the realistic models of Aerial-to-Terrestrial and Device-to-Device channels. The numerical results reveal that OSTC obviously outperforms the opportunistic relaying in the presence of outdated CSI. Moreover, the improvement of reliability comes without any sacrifice in the spectral efficiency.

关键词： BASE STATION space-time coding Terrestrial network Raleigh fading channels networks(communications) Balloon Device Component relaying spectral efficiency time coding Disasters ANTENNA

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A Multi-Step Furnace Temperature Prediction Model for Regenerative Aluminum Smelting Based on Reversible Instance Normalization-Convolutional Neural Network-Transformer

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PROCESSES 2024年第11期12卷 2438页

作者： Dai, Jiayang Ling, Peirun Shi, Haofan Liu, Hangbin Guangxi Univ Sch Elect Engn Nanning 530004 Peoples R China

In the regenerative aluminum smelting process, the furnace temperature is critical for the quality and energy consumption of the product. However, the process requires protective sensors, making real-time furnace temperature measurement costly, while the strong nonlinearity and distribution drift of the process data affect furnace temperature prediction. To handle these issues, a multi-step prediction model for furnace temperature that incorporates reversible instance normalization (RevIN), convolutional neural network (CNN), and Transformer is proposed. First, the self-attention mechanism of the Transformer is combined with CNN to extract global and local information in the furnace temperature data, thus addressing the strong nonlinear characteristics of the furnace temperature. Second, RevIN with learnable affine transformation is utilized to address the distribution drift in the furnace temperature data. Third, the temporal correlation of the prediction model is enhanced by a time-coding method. The experimental results show that the proposed model demonstrates higher prediction accuracy for furnace temperature at different prediction steps in the regenerative aluminum smelting process compared to other models.

关键词： reversible instance normalization (RevIN) convolutional neural network (CNN) Transformer time coding

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Dynamic Image Quantization Using Leaky Integrate-and-Fire Neurons

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2021年 30卷 4305-4315页

作者： Doutsi, Effrosyni Fillatre, Lionel Antonini, Marc Tsakalides, Panagiotis Fdn Res & Technol Hellas FORTH Iraklion 71110 Greece Univ Cote Azur Lab Informat Signaux & Syst Sophia Antipolis I3S Lab CNRS F-06108 Nice France Univ Crete Dept Comp Sci Iraklion 70013 Greece

This paper introduces a novel coding/decoding mechanism that mimics one of the most important properties of the human visual system: its ability to enhance the visual perception quality in time. In other words, the brain takes advantage of time to process and clarify the details of the visual scene. This characteristic is yet to be considered by the state-of-the-art quantization mechanisms that process the visual information regardless the duration of time it appears in the visual scene. We propose a compression architecture built of neuroscience models;it first uses the leaky integrate-and-fire (LIF) model to transform the visual stimulus into a spike train and then it combines two different kinds of spike interpretation mechanisms (SIM), the time-SIM and the rate-SIM for the encoding of the spike train. The time-SIM allows a high quality interpretation of the neural code and the rate-SIM allows a simple decoding mechanism by counting the spikes. For that reason, the proposed mechanisms is called Dual-SIM quantizer (Dual-SIMQ). We show that (i) the time-dependency of Dual-SIMQ automatically controls the reconstruction accuracy of the visual stimulus, (ii) the numerical comparison of Dual-SIMQ to the state-of-the-art shows that the performance of the proposed algorithm is similar to the uniform quantization schema while it approximates the optimal behavior of the non-uniform quantization schema and (iii) from the perceptual point of view the reconstruction quality using the Dual-SIMQ is higher than the state-of-the-art.

关键词： Quantization (signal) Image reconstruction Neurons Visualization Image coding Transforms Mathematical model Uniform quantization non-uniform quantization leaky integrate-and-fire model spikes rate coding time coding

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Minute-scale periodicity of neuronal firing in the human entorhinal cortex

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CELL REPORTS 2023年第11期42卷 113271页

作者： Aghajan, Zahra M. Kreiman, Gabriel Fried, Itzhak Univ Calif Los Angeles David Geffen Sch Med Dept Neurosurg Los Angeles CA 90095 USA Harvard Med Sch Childrens Hosp Boston MA 02115 USA MIT Ctr Brains Minds & Machines Cambridge MA 02139 USA Univ Calif Los Angeles Jane & Terry Semel Inst Neurosci & Human Behav Dept Psychiat & Biobehav Sci Los Angeles CA 90095 USA Tel Aviv Univ Fac Med IL-69978 Tel Aviv Israel

Grid cells in the entorhinal cortex demonstrate spatially periodic firing, thought to provide a spatial map on behaviorally relevant length scales. Whether such periodicity exists for behaviorally relevant time scales in the human brain remains unclear. We investigate neuronal firing during a temporally continuous experience by presenting 14 neurosurgical patients with a video while recording neuronal activity from multiple brain regions. We report on neurons that modulate their activity in a periodic manner across different time scales- from seconds to many minutes, most prevalently in the entorhinal cortex. These neurons remap their dominant periodicity to shorter time scales during a subsequent recognition memory task. When the video is presented at two different speeds, a significant percentage of these temporally periodic cells (TPCs) maintain their time scales, suggesting a degree of invariance. The TPCs' temporal periodicity might complement the spatial periodicity of grid cells and together provide scalable spatiotemporal metrics for human experience.

关键词： human neurons medial temporal lobe time memory temporal representation electrophysiology time coding periodic time cells Research topic(s)CP: Neuroscience

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Encoding specificity of scale-free spiking neural network under different external stimulations

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NEUROCOMPUTING 2020年 418卷 126-138页

作者： Guo, Lei Hou, LiTing Wu, YouXi Lv, Huan Yu, HongLi Hebei Univ Technol State Key Lab Reliabil & Intelligence Elect Equip Tianjin 300130 Peoples R China Hebei Univ Technol Tianjin Key Lab Bioelectromagnet Technol & Intell Tianjin 300130 Peoples R China Hebei Univ Technol Sch Artificial Intelligence Tianjin 300401 Peoples R China

Neural information coding is the foundation of information processing in the nervous system. The specificity of coding is the key issue of efficiently realizing complex cognition functions. In this study, a scalefree spiking neural network (SFSNN) is constructed based on synaptic plasticity and scale-free topology. The time coding properties of the SFSNN under different intensities of different stimulations including Gauss stimulation, impulse stimulation, and AC electric field stimulation are analyzed. On this basis, the specificity of time coding and the mechanism of time coding are studied emphatically. The experimental results show that: (1) Under each kind of stimulation, the inter-spike interval (ISI) is decreased, and the stronger the stimulation intensity is, the smaller the ISI is. (2) The time coding patterns have high similarity under same kind of stimulation, which is verified by the cosine similarity algorithm;the time coding patterns have high difference under different kind of stimulations, which is verified by the Kmeans clustering algorithm. Therefore, the time coding specificity is verified by the algorithms. (3) The relationship between the synaptic plasticity and time coding is established based on the Pearson correlation coefficient. The dynamic regulation of synaptic plasticity is significantly correlated with time coding under each kind of stimulation, which implies that the dynamic regulation of synaptic plasticity is the intrinsic factor of time coding mechanism. (c) 2020 Elsevier B.V. All rights reserved.

关键词： Scale-free spiking neural network Synaptic plasticity time coding Inter-spike interval

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FPT-spike: a flexible precise-time-dependent single-spike neuromorphic computing architecture

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CCF TRANSACTIONS ON HIGH PERFORMANCE COMPUTING 2020年第3期2卷 254-271页

作者： Liu, Tao Quan, Gang Wen, Wujie Lehigh Univ Dept Elect & Comp Engn Bethlehem PA 18015 USA Florida Int Univ Dept Elect & Comp Engn Miami FL 33199 USA

Modern Artificial Neural networks (ANNs) like Convolutional Neural Network (CNN), have found broad applications in real-world cognitive tasks. One challenging faced by these models is their tremendous memory and computing resource requirement. This also greatly hinders their adoptions from resource-constraint platforms, such as drone, mobile phone and IoT devices. Recently the brain-inspired spiking neural network (SNN) has been demonstrated as a promising solution for delivering more impressive computing and power efficiency. For SNNs, a large body of prior work were conducted on the spiking system design with a focus on using the spike firing rate (or rate-coded) for fulfilling the practical cognitive tasks. Such rate-based designs can underestimate the energy efficiency, throughput and system flexibility of SNNs. On the other hand, the potentials of time-based SNN are not fully unleashed in real applications due to lack of efficient coding and practical learning schemes in temporal domain. In this work, we make an early attempt to fill this gap: that said, a flexible precise-time-dependent single-spike neuromorphic computing architecture, namely "FPT-Spike", is developed. "FPT-spike" relies on three hardware-favorable components: precise ultra-sparse spike temporal encoding, efficient supervised temporal learning and fast asymmetric decoding, to realize flexible spatial-temporal information trade-off for neural network size reduction without scarifying data processing capability. Extensive experimental results show that "FPT-Spike" outperforms rate-based SNN and ANN significantly in three aspects: network size, processing speed and power consumption, demonstrating great potentials for its deployment in edge devices.

关键词： Neuromorphic computing Spiking neural network time coding

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Space-time coding with receive combiner bank for multiple-input-multiple-output system under multi-user cochannel interference

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IET COMMUNICATIONS 2013年第2期7卷 180-186页

作者： Wang, Jui Teng Natl Chi Nan Univ Grad Inst Commun Engn Puli Nantou Taiwan

Space-time coding with receive combiner bank (STC-RCB), in which a bank of receive combiners is added before the space-time decoder for interference-plus-noise suppression, is proposed. Without loss of generality, the author consider space-time block code (STBC) to be the representative of STC and study the performance for (STBC-RCB). The author derive the output signal to interference-plus-noise ratio (SINR) (of the space-time decoder) for STBC-RCB under multi-user cochannel interference. By regarding STBC as a special case of STBC-RCB, the author also derive the output SINR for STBC under multi-user cochannel interference. Simulation results show that the output SINR of STBC-RCB can be much larger than that of STBC, also, they show that STBC-RCB can adopt the appropriate receive combining strategy in the RCB to further improve the performance.

关键词： time coding outgoing signal Cochannel interference SINR space time block coding combiner output system space-time coding multiple input multiple output systems

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