- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Non-Uniform Quantization Codebook Based Hybrid Precoding to Reduce Feedback Overhead in Millimeter Wave MIMO Systems
摘要： In this paper, we propose two non-uniform quantization (NUQ) codebook based hybrid precoding schemes for two main hybrid precoding implementations, i.e., the full-connected structure and the sub-connected structure, to reduce the feedback overhead in millimeter wave single user multiple-input multiple-output (SU-MIMO) systems. Specifically, we firstly group the angles of the arrive/departure (AOAs/AODs) of the scattering paths into several spatial lobes by exploiting the sparseness property of the millimeter wave in the angular domain, which divides the total angular domain into effective spatial lobes' coverage angles and ineffective coverage angles. Then, we map the quantization bits non-uniformly to different coverage angles and construct NUQ codebooks, where high numbers of quantization bits are employed for the effective coverage angles to quantize AoAs/AoDs and zero quantization bit is employed for ineffective coverage angles. Finally, two low-complexity hybrid analog/digital precoding schemes are proposed that utilize the NUQ codebooks. Simulation results demonstrate that, the proposed two NUQ codebook based hybrid precoding schemes achieve near-optimal spectral efficiencies and show the superiority in reducing the feedback overhead compared with the uniform quantization codebook based works.
关键词： feedback overhead,non-uniform quantization,spatial lobe,Millimeter wave communication,hybrid precoding
更新于2025-09-23 15:23:52
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In-band Full-Duplex Relay-Assisted Millimeter-Wave System Design
摘要： Millimeter-wave (mmWave) communication is a promising technology for future wireless systems due to the availability of huge unlicensed bandwidth. However, the need for large number of radio frequency (RF) chains associated with the antenna array and the corresponding increase in hardware complexity and power consumption are major stumbling blocks to its implementability. In this paper, we propose a low-complexity in-band full-duplex relay-assisted mmWave communication system design. We obtain the proposed multiple-input multiple-output analog–digital hybrid transceivers and relay filters by minimizing the overall sum-mean-square-error while mitigating the effect of residual loopback self-interference (LSI) in the system. The number of RF chains required in the proposed design is less than the number of antennas. We first present a design assuming the availability of perfect channel state information (CSI) at all the nodes. Later, we extend it to a robust design assuming a more realistic scenario, where the available CSI is imperfect. Furthermore, the LSI channel knowledge is assumed to be imperfect for both the designs rendering them robust to errors in loopback CSI. We employ sparse approximation technique to reduce the hardware complexity in the proposed system designs. The proposed algorithms are shown to converge to a limit even though the global convergence is hard to prove since the overall problem is non-convex. The hardware complexity-performance tradeoff of the proposed design is analyzed. Furthermore, the resilience of the robust design in the presence of CSI errors and the performance of both the proposed designs over various parameters are illustrated via numerical simulations.
关键词： robust design,Full-duplex,residual self-interference,millimeter-wave communication,hybrid beamforming
更新于2025-09-23 15:22:29
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Hybrid Precoding for Wideband Millimeter-Wave Systems with Finite Resolution Phase Shifters
摘要： In this paper, we study the hybrid analog-digital precoding for OFDM based-wideband millimeter wave (mmwave) communication systems. Since the analog precoding matrix is performed in the time domain and used for the entire bandwidth while the digital precoding matrices are performed on a per-subcarrier basis, the resulting wideband hybrid precoding problem becomes very complicated. Moreover, in practice phase shifter (PS) usually has only finite resolution, which brings more difficulties. To solve the resulting difficult problem, we propose an efficient algorithm by leveraging the penalty decomposition method. Simulation results are finally provided to confirm the effectiveness and superiority of the proposed algorithm and show the performance improvement than the existing algorithm.
关键词： finite resolution phase shifter,wideband hybrid precoding,decomposition method,Wideband millimeter wave communication
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Synchrotron and optical probing of hybrid organic-inorganic perovskite halides for photovoltaics
摘要： Supporting high data rate wireless connectivity among wearable devices in a dense indoor environment is challenging. This is primarily due to bandwidth scarcity when many users operate multiple devices simultaneously. The millimeter-wave (mmWave) band has the potential to address this bottleneck, thanks to more spectrum and less interference because of signal blockage at these frequencies. In this paper, we explain the potential and challenges associated with using mmWave for wearable networks. To provide a means for concrete analysis, we present a system model that admits easy analysis of dense, indoor mmWave wearable networks. We evaluate the performance of the system while considering the unique propagation features at mmWave frequencies, such as human body blockages and re?ections from walls. One conclusion is that the non-isotropy of the surroundings relative to a reference user causes variations in system performance depending on the user location, body orientation, and density of the network. The impact of using antenna arrays is quanti?ed through analytic closed-form expressions that incorporate antenna gain and directivity. It is shown that using directional antennas, positioning the transceiver devices appropriately, and orienting the human user body in certain directions depending on the user location result in gigabits-per-second achievable ergodic rates for mmWave wearable networks.
关键词： personal communication networks,wearable computers,signal to noise ratio,Millimeter wave communication,performance analysis,analytic models,indoor communication,internet of things,virtual reality
更新于2025-09-23 15:19:57
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Sampled-Data Adaptive ESO Based Composite Control for Nano-Positioning Systems
摘要： In this paper, we demonstrate ultra-fast millimeter wave beam steering with settling times below 50 ps. A phased array antenna with two elements is employed to realize beam steering. The phased array feeder is implemented with a recently introduced time delay line that provides, at the same time, an ultra-fast tunability, broadband operation, and continuous tuning. Our implementation is used to perform symbol-by-symbol steering. In our demonstration, the beam direction is switched between two sequentially transmitted symbols toward two receivers placed 30° apart. We show the successful symbol-by-symbol steering for data streams as fast as 10 GBd. The suggested scheme shows that the ultra-fast beam steering is becoming practical and might ultimately enable novel high bit-rate multiple access schemes.
关键词： microwave photonics,millimeter wave communication,Ultra-fast beam steering,radio access network
更新于2025-09-23 15:19:57
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[IEEE 2019 International Conference on Sustainable Technologies for Industry 4.0 (STI) - Dhaka, Bangladesh (2019.12.24-2019.12.25)] 2019 International Conference on Sustainable Technologies for Industry 4.0 (STI) - A New Medium Voltage Modular Multilevel Inverter with Advanced Carrier-Based Pulse Width Modulation for Solar Photovoltaic Systems
摘要： Millimeter-wave (mmWave) communication operated in frequency bands between 30 and 300 GHz has attracted extensive attention due to the potential ability of offering orders of magnitude greater bandwidths combined with further gains via beamforming and spatial multiplexing from multi-element antenna arrays. mmwave system may exploit the hybrid analog and digital precoding to achieve simultaneously the diversity, array and multiplexing gain with a lower cost of implementation. Motivated by this, in this paper, we investigate the design of hybrid precoder and combiner with sub-connected architecture, where each radio frequency chain is connected to only a subset of base station antennas from the perspective of energy efficient transmission. The problem of interest is a non-convex and NP-hard problem that is difficult to solve directly. In order to address it, we resort to design a two-layer optimization method to solve the problem of interest by exploiting jointly the interference alignment and fractional programming. First, the analog precoder and combiner are optimized via the alternating-direction optimization method where the phase shifter can be easily adjusted with an analytical structure. Then, we optimize the digital precoder and combiner based on an effective multiple-input multiple-output channel coefficient. The convergence of the proposed algorithms is proved using the monotonic boundary theorem and fractional programming theory. Extensive simulation results are given to validate the effectiveness of the presented method and to evaluate the energy efficiency performance under various system configurations.
关键词： analog precoding and combining,interference alignment,energy efficiency,Millimeter-wave communication,multiple-input multiple-output (MIMO) system
更新于2025-09-23 15:19:57
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[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - The Response Characteristics of Dielectric Logging in Anisotropic Formation
摘要： Millimeter-wave (mmWave) communication operated in frequency bands between 30 and 300 GHz has attracted extensive attention due to the potential ability of offering orders of magnitude greater bandwidths combined with further gains via beamforming and spatial multiplexing from multi-element antenna arrays. mmwave system may exploit the hybrid analog and digital precoding to achieve simultaneously the diversity, array and multiplexing gain with a lower cost of implementation. Motivated by this, in this paper, we investigate the design of hybrid precoder and combiner with sub-connected architecture, where each radio frequency chain is connected to only a subset of base station antennas from the perspective of energy efficient transmission. The problem of interest is a non-convex and NP-hard problem that is difficult to solve directly. In order to address it, we resort to design a two-layer optimization method to solve the problem of interest by exploiting jointly the interference alignment and fractional programming. First, the analog precoder and combiner are optimized via the alternating-direction optimization method where the phase shifter can be easily adjusted with an analytical structure. Then, we optimize the digital precoder and combiner based on an effective multiple-input multiple-output channel coefficient. The convergence of the proposed algorithms is proved using the monotonic boundary theorem and fractional programming theory. Extensive simulation results are given to validate the effectiveness of the presented method and to evaluate the energy efficiency performance under various system configurations.
关键词： Millimeter-wave communication,energy efficiency,interference alignment,analog precoding and combining,multiple-input multiple-output (MIMO) system
更新于2025-09-23 15:19:57
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User scheduling for capacity-Jain’s fairness tradeoff in millimeter-wave MIMO systems
摘要： This paper investigates user scheduling in millimeter-wave multiple-input multiple-output systems that can achieve a tradeoff between capacity and Jain’s fairness index. By decomposing the original problem into digital beamforming design, duration allocation, and analog beamforming design, each subproblem is solvable. It is proved that the duration allocation problem possesses a property such that the convex optimization algorithm can be employed for the near optimal result. Moreover, the analog beamforming vectors and the user grouping are designed to avoid interference caused by the reuse of the same subspace. Finally, the computational complexity of the proposed approach is analyzed and is compared with that of other approaches. The simulations verify that the proposed approach can achieve the highest fairness and a higher capacity than approaches of close fairness.
关键词： Scheduling,MIMO systems,Millimeter-wave communication,Beams
更新于2025-09-19 17:15:36
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Nanoscale Transfer Printing for the Heterogeneous Integration of Semiconductor Nanowire Lasers
摘要： InP-based high electron mobility transistors (InP-HEMTs) and graphene-channel FETs (G-FETs) are experimentally examined as photonic frequency converters for future broadband optical and wireless communication systems. Optoelectronic properties and three-terminal functionalities of the InP-HEMTs and G-FETs are exploited to perform single-chip photonic double-mixing operation over the 120 GHz wireless communication band. A 10 Gbit/s-class data signal on a 112.5 GHz carrier is mixed down to a 25 GHz IF band with an 87.5 GHz LO signal that is simultaneously self-generated from an optically injected photomixed beat note. The results suggest that the intrinsic channel of the G-FET can achieve a speed performance that is superior to that of an InP-HEMT having an equivalent device feature size. The reduction of the extrinsic parasitic resistances and the implementation of an efficient photo-absorption structure in the G-FET may allow a millimeter-wave and sub-THz photonic frequency conversion with a sufficiently high conversion gain for practical purposes.
关键词： millimeter wave photonics,frequency conversion,FETs,millimeter wave communication,InP,graphene,HEMTs,radio access networks
更新于2025-09-19 17:13:59
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Facile enhancement of optical sensitivity in GaN ultraviolet photodetectors by using in-situ plano-convex polymer lens
摘要： InP-based high electron mobility transistors (InP-HEMTs) and graphene-channel FETs (G-FETs) are experimentally examined as photonic frequency converters for future broadband optical and wireless communication systems. Optoelectronic properties and three-terminal functionalities of the InP-HEMTs and G-FETs are exploited to perform single-chip photonic double-mixing operation over the 120 GHz wireless communication band. A 10 Gbit/s-class data signal on a 112.5 GHz carrier is mixed down to a 25 GHz IF band with an 87.5 GHz LO signal that is simultaneously self-generated from an optically injected photomixed beat note. The results suggest that the intrinsic channel of the G-FET can achieve a speed performance that is superior to that of an InP-HEMT having an equivalent device feature size. The reduction of the extrinsic parasitic resistances and the implementation of an efficient photo-absorption structure in the G-FET may allow a millimeter-wave and sub-THz photonic frequency conversion with a sufficiently high conversion gain for practical purposes.
关键词： millimeter wave photonics,frequency conversion,FETs,millimeter wave communication,InP,graphene,HEMTs,radio access networks
更新于2025-09-19 17:13:59