- 标题
- 摘要
- 关键词
- 实验方案
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Subcarrier-Index Modulated Multicarrier Space-Time Shift Keying: Achievable Rate, Performance and Design Guidelines
摘要： Multicarrier (MC) space-time shift keying (STSK) relying on the concept of subcarrier-index modulated orthogonal frequency division multiplexing (SIM-OFDM) is proposed. In conventional MC-STSK system, the performance erosion of STSK in dispersive channels is mitigated by employing OFDM. The SIM-OFDM aided MC-STSK activates a specified limited number of subcarriers for transmitting the STSK codewords. The indices of the activated subcarriers provide additional multiplexing gain. A new receiver architecture, which uses the single-stream maximum-likelihood (ML) detector of STSK and the subcarrier activation principle of SIM-OFDM, is designed. A soft decision logarithmic likelihood ratio (LLR) based detector is also conceived. Helpful design guidelines are provided for the system. The achievable rate, complexity and performance of the system are analytically quantified and verified with the aid of numerical simulations. The system is capable of overcoming the impairments imposed by wideband channels, is benefited from index modulation as well as from STSK. The scheme exhibits an improved error performance compared to the classic OFDM-based STSK as a result of the more reliable detection of the subcarrier index bits.
关键词： Space-time shift keying (STSK),multiple-input multiple-output (MIMO),orthogonal frequency division multiplexing (OFDM),subcarrier index modulation
更新于2025-09-23 15:23:52
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A decoupling method between two tri-band antennas for WLAN/WiMAX applications
摘要： A decoupling method between two tri-band antennas for WLAN/WiMAX applications is presented. A monopole is first designed with tri-band characteristic; three resonating frequencies are generated by three separate resonators. Then, two tri-band monopoles are employed to develop a MIMO antenna system. The resonators of low band can reduce the mutual coupling for two higher bands by suppressing surface wave propagation. Finally, coupling reduction at low band is achieved by a Ω-shaped metal line to neutralize original coupling. The proposed MIMO antenna covers the 2.4/5.8 GHz WLAN and 3.5 GHz WiMAX bands, with the measured mutual coupling lower than ?18 dB.
关键词： multiple-input multiple-output (MIMO) antenna,decoupling method,triple-band
更新于2025-09-23 15:23:52
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Layered Adaptive Collaborative Constellation for MIMO Visible Light Communication
摘要： In this paper, we propose a novel technique to effectively design a channel adaptive collaborative constellation called the layered adaptive collaborative constellation (LACC) for multiple-input multiple-output visible light communications. Recently, a channel-adaptive space-collaborative constellation (CASCC) that designs the constellation with the consideration of channel into the model to improve the receiver mobility and enhance the error performance. However, this scheme only considers into optimization four constellation points that form a diamond shape in the receiver space. Our proposed scheme effectively exploits the layered structure of collaborative constellation and overcomes the aforementioned drawbacks of CASCC. Furthermore, an improved low-complexity maximum likelihood (ML)-based detector is derived. Simulation results show that the LACC can achieve some performance gain, compared with previous constellation design schemes for different scenarios, especially really high-correlation channels and under imperfect channel state information. Moreover, the proposed detector drastically reduces computational complexity while maintaining the same performance as a traditional ML detector.
关键词： maximum likelihood (ML) detection,multiple-input multiple-output (MIMO),Visible light communications (VLC),space collaborative constellation
更新于2025-09-23 15:23:52
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Soft-Output Detection Methods for Sparse Millimeter Wave MIMO Systems with Low-Precision ADCs
摘要： In this paper, we propose computationally-efficient yet near-optimal soft-output detection methods for coded millimeter wave (mmWave) multiple-input multiple-output (MIMO) systems with low-precision analog-to-digital converters (ADCs). The underlying idea of the proposed methods is to construct an extremely sparse inter-symbol-interference (ISI) channel model by jointly exploiting the delay-domain sparsity in mmWave channels and a high quantization noise caused by low-precision ADCs. Then we harness this sparse channel model to create a trellis diagram with a reduced number of states and a factor graph with very sparse edge connections, which are used for computationally-efficient soft-output detection methods. Using the reduced trellis diagram, we present a soft-output detection method that computes the log-likelihood ratios (LLRs) of coded bits by optimally combining the quantized received signals obtained from multiple receive antennas using a forward-and-backward algorithm. To reduce the computational complexity further, we also present a low-complexity detection method using the sparse factor graph to compute the LLRs in an iterative fashion based on a belief propagation algorithm. Simulations results demonstrate that the proposed soft-output detection methods provide significant frame-error-rates gains compared to the existing frequency-domain equalization techniques in a coded mmWave MIMO system using one or two bit ADCs.
关键词： soft-output detection,time-domain equalization,low-precision analog-to-digital converter (ADC),multiple-input-multiple-output (MIMO),Millimeter wave communications
更新于2025-09-23 15:22:29
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A Simple Channel Independent Beamforming Scheme with Parallel Uniform Circular Array
摘要： In this letter, we consider a uniform circular array (UCA) based line-of-sight (LOS) multiple-input-multiple-output (MIMO) system, where the transmit and receive UCAs are parallel but non-coaxial with each other. We propose a simple channel independent beamforming scheme with fast symbol-wise maximum likelihood (ML) detection.
关键词： multiple-input-multiple-output (MIMO),channel independent beamforming,Uniform circular array (UCA),fast maximum likelihood (ML)
更新于2025-09-23 15:22:29
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Characteristic Mode Analysis and Design of Wide Band MIMO Antenna Consisting of Metamaterial Unit Cell
摘要： This paper presents a full wave simulation and characteristic mode-based design of a multiple-input-multiple-output (MIMO) antenna at 5.8 GHz for wireless local area network applications. The driven analysis comprises two antennas that are placed orthogonal to each other. A metamaterial unit structure in the form of a rectangular loop resonator is placed around the antenna element to reduce the electromagnetic interference and to increase the isolation between the two monopoles. A characteristic mode technique is employed to find out the dominant mode of the proposed antenna without a feeding port. It was revealed that mode 1 was the dominant mode among the three modes used. The MIMO antenna is constructed and measured using a vector network analyzer. A good isolation of less than 25 dB was attained with a wide impedance bandwidth of 65.5%.
关键词： rectangular loop resonator,multiple-input-multiple-output (MIMO),envelope correlation coefficient,mutual coupling
更新于2025-09-23 15:22:29
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Spatial-Based Chipless RFID System
摘要： Conventional techniques in chipless RFID systems are incapable of fully overcoming the key challenges of modern identification applications, including high data capacity, low tag cost and reliable operation. The idea of electromagnetic (EM) imaging in chipless RFID systems is a promising technique that shows many advantages over other conventional approaches. This paper reviews conventional chipless RFID technology and provides a comprehensive analysis of advanced millimeter wave spatial-based (also known as image-based) chipless RFID systems with an optimized MIMO-SAR technique for high-resolution image acquisition and a quick reading process.
关键词： Multiple-input multiple-output (MIMO),Millimeter wave (mmwave),Chipless radio frequency identification (RFID),EM imaging,Virtual antenna array,Synthetic aperture radar (SAR)
更新于2025-09-23 15:22:29
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Omega-K Algorithm for Near-Field 3-D Image Reconstruction Based on Planar SIMO/MIMO Array
摘要： The characteristics of range cell migration (RCM) under single-input-multiple-output (SIMO) bi-static geometry are studied and an omega-K algorithm for near-field 3-D imaging based on planar SIMO or multiple-input-multiple-output (MIMO) array is proposed. The RCM and the linear part of the range offset (RO) within SIMO data are corrected by employing a 3-D Stolt transformation. The residual range error is further compensated by phase multiplication and an image-domain interpolation. Reconstruction for a MIMO aperture can be achieved by adding together all the focusing results from its SIMO subarrays. The implementation details of the algorithm are described. The imaging resolution and the sampling requirements for a MIMO aperture are discussed. Since the RO correction is achieved by an approximate way, the spatial limitation for accurate reconstruction is also given. The imaging accuracy and the high efficiency of the algorithm are demonstrated both by simulations and experiments with various distributed targets based on planar MIMO arrays. Real-time 3-D imaging for planar SIMO/MIMO aperture is expected to be achieved by using the algorithm.
关键词： Omega-K (ωK),bi-static,multiple-input-multiple-output (MIMO),3-D imaging
更新于2025-09-23 15:21:21
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A Compact 24x 24 Channel MIMO FMCW Radar System Using a Substrate Integrated Waveguide-Based Reference Distribution Backplane
摘要： In this article a compact 120-GHz multiple-input-multiple-output (MIMO) imaging radar is presented. With a module size of only 25 cm, an angular resolution of less than 0.9? is obtained in elevation and azimuth direction using 24 transmitters and 24 receivers. The hardware is based on a SiGe:C MMIC technology and integrated into a modular frontend and backend structure. This article presents the overall hardware architecture of the RF-frontend, including a novel reference oscillator distribution concept and a connectorless board-to-board transition based on substrate integrated waveguides. A fully integrated backend is shown, and the entire radar system is evaluated experimentally and the imaging results are presented, demonstrating the large potential of the presented millimeter-wave 3-D imaging radar.
关键词： multiple-input-multiple-output (MIMO) radar,substrate integrated waveguides (SIWs),Millimeter-wave sensing
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE 5G World Forum (5GWF) - Silicon Valley, CA, USA (2018.7.9-2018.7.11)] 2018 IEEE 5G World Forum (5GWF) - Feasibility and Challenges of Over-The-Air Testing for 5G Millimeter Wave Devices
摘要： The evolution from 1G through 5G cellular technologies has been fueled mainly by the insatiable need for speed, lower latency, high reliability and enhanced flexibility of use across the wireless ecosystem. Using multiple antennas in conjunction with complex modulation schemes has rendered each generation of cellular technology an enhanced version over its former counterpart. 5G technology aims to exploit previously unchartered higher millimeter wave (mmWave) frequencies & larger bandwidths towards realizing the goal of greater data throughput, while simultaneously enhancing data reliability and reducing latency. The small wavelength of mmWave signals makes it possible to design 5G devices using several multi-element phased array antennas with small element-element spacing. However, unlike the antenna designs of 2G/3G/4G devices, 5G multi-element antennas would be integrated with the radio frequency integrated circuit (RFIC) board of the 5G device. The tight integration between antennas and RFIC renders the antenna port of the device under test (DUT) inaccessible for physical connections using cables/connectors to test equipment. Since conducted testing with cables is not feasible anymore, radiated over-the-air (OTA) testing becomes mandatory for 5G mmWave device verification. This paper aims to assess the feasibility of candidate OTA test methods for 5G mmWave test requirements. The challenges of testing 5G mmWave devices over-the-air have been elucidated and alternative OTA test solutions for overcoming these challenges have also been discussed.
关键词： multi-probe anechoic chamber (MPAC),Multiple-input multiple-output (MIMO),compact antenna test range (CATR),far-field,near-field,antenna arrays
更新于2025-09-23 15:21:01