A5100431275- Millimeter-Wave Propagation and Modeling
- Advanced MIMO Systems Optimization
- Microwave Engineering and Waveguides
- Power Line Communications and Noise
- Indoor and Outdoor Localization Technologies
- Antenna Design and Analysis
- Vehicular Ad Hoc Networks (VANETs)
- Full-Duplex Wireless Communications
- Antenna Design and Optimization
- Underwater Vehicles and Communication Systems
- Cooperative Communication and Network Coding
- Advanced Wireless Communication Techniques
- Electromagnetic Compatibility and Measurements
- Telecommunications and Broadcasting Technologies
- Radio Wave Propagation Studies
- Radio Frequency Integrated Circuit Design
- RNA and protein synthesis mechanisms
- Target Tracking and Data Fusion in Sensor Networks
- Advancements in PLL and VCO Technologies
- Photonic and Optical Devices
- Radar Systems and Signal Processing
- Military Defense Systems Analysis
- Speech and Audio Processing
- Genomics and Phylogenetic Studies
- Animal Disease Management and Epidemiology
University of Southern California
2013-2023
Fudan University
2021-2023
Southern University of Science and Technology
2023
Chongqing Metrology Quality Inspection and Research Institute
2023
Tongji University
2023
Samsung (United States)
2019-2022
Google (United States)
2022
Research!America (United States)
2019-2022
The University of Sydney
2022
Chengdu University of Information Technology
2022
Massive MIMO systems are well-suited for mm-Wave communications, as large arrays can be built with reasonable form factors, and the high array gains enable coverage even outdoor communications. One of main obstacles using such in frequency-division duplex mode, namely, overhead feedback channel state information (CSI) to transmitter, mitigated by recently proposed joint spatial division multiplexing (JSDM) algorithm. In this paper, we analyze performance algorithm some <bold...
Discriminating between line-of-sight (LOS) and non-line-of-sight (NLOS) conditions, or <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LOS identification</i> , is important for a variety of purposes in wireless systems, including localization channel modeling. LOS identification especially challenging vehicle-to-vehicle (V2V) networks since physical effects that occur at different spatial/temporal scales can affect the presence LOS. This...
We present a decade of evolution and production experience with Jupiter datacenter network fabrics. In this period has delivered 5x higher speed capacity, 30% reduction in capex, 41% power, incremental deployment technology refresh all while serving live traffic. A key enabler for these improvements is evolving from Clos to direct-connect topology among the machine aggregation blocks. Critical architectural changes include: interconnection layer employing Micro-Electro-Mechanical Systems...
Heterogeneous Networks (HetNets) are known to enhance the bandwidth efficiency and throughput of wireless networks by more effectively utilizing network resources. However, higher density users access points in HetNets introduces significant inter-user interference that needs be mitigated through complex sophisticated cancellation schemes. Moreover, due channel attenuation presence hardware impairments, e.g., phase noise amplifier nonlinearities, vast millimeter-wave band has not been fully...
In this paper, we present a novel real-time multiple-input multiple-output (MIMO) channel sounder for the 28 GHz band. Until now, most investigations of directional characteristics millimeter-wave channels have used mechanically rotating horn antennas. contrast, presented here is based on phased array structure that performs fast <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">electronic</i> steering beams in horizontal and vertical domains....
Considering the design of two-stage beamformers for downlink multi-user massive multiple-input multiple-output systems in frequency division duplexing mode, this paper investigates case where both link ends are equipped with hybrid digital/analog beamforming structures. A virtual sectorization is realized by channel-statistics-based user grouping and analog beamforming, equipment only needs to feedback its intra-group effective channel, overall cost channel state information (CSI)...
Since millimeter-wave (mm-wave) communications systems deployed in urban environments will be an important component of next-generation cellular communications, it is to understand the propagation channels those working in. This paper provides overview state art mm-wave channel modeling, and outlines directions for future research. Propagation at differs several critical aspects from microwave frequencies: much higher free-space pathloss, a smaller number multipath components, inefficiency...
Outdoor to indoor penetration loss is one of the crucial challenges faced at millimeter-wave frequencies. This paper presents results from 28-GHz channel sounding campaigns performed investigate impact this phenomenon on wireless propagation characteristics in small cell and fixed access scenarios. The measurements are with a real-time sounder equipped phased array antennas that allow beam-forming electronic beam steering for directionally resolved measurements. Thanks short measurement time...
An all-digital phase interpolator (PI)-based clock and data recovery (CDR) is proposed in this paper to accommodate any rate continuously from 1 16 Gb/s with quadrature sampling clocks 4 8 GHz. A new low-power two-step PI (TSPI) high linearity over 4-8 GHz range presented. The CDR control loop adopts a multimode detection scheme enabling continuous support. digital architecture not only eliminates the large filtering capacitor but also makes design more tolerant process, voltage, temperature...
Fifth generation cellular systems will operate in a wide range of frequencies, covering both the traditional bands, and mm-wave frequency either selecting specific band or operating multiple bands simultaneously. For design such systems, detailed understanding dependence propagation channel is essential. While many measurements exist microwave (< 6 GHz) near (> 20 GHz), results are not easily comparable, furthermore transition between these well studied. This paper aims to bridge gap by...
Vehicle-to-vehicle (V2V) wireless communications have many envisioned applications for ensuring traffic safety and addressing congestion. However, developing suitable communication systems standards this purpose requires developers to accurate models the V2V propagation channel. Likewise, dynamic evolution of multipath components (MPCs) in channels has not been well modeled existing models. In paper, we propose a geometry-based stochastic channel model lightly built-up urban environment then...
Since African swine fever virus (ASFV) replication is closely related to its host's machinery, codon usage of viral genome can be subject selection pressures. A better understanding give new insights into evolution. We implemented information entropy and revealed that the nucleotide pattern ASFV significantly associated with isolation factors (region time), especially usages thymine cytosine. Despite domination adenine in genome, we found mutation pressure alters overall ASFV, followed by...
Path loss models are the most fundamental part of wireless propagation channel models. is typically modelled as a (single‐slope or multi‐slope) power‐law dependency on distance plus log‐normally distributed shadowing attenuation. Determination parameters this model usually done by fitting to results from measurements ray tracing. The authors show that typical least‐square those data points inherently biased give best link distances happen have more evaluation points. A weighted method...
This paper describes a high-resolution parameter estimation algorithm applied to the vehicle-to-vehicle (V2V) multi-dimensional channel measurements. The algorithm, which is based on maximum likelihood estimator, jointly estimates parameters of multipath components, such as time-of-arrival, direction departure, arrival, and Doppler shift. It serves provide comprehensive understanding V2V propagation channel. We propose computationally attractive methods initialize in global search evaluate...
Downlink channel estimation in massive MIMO systems is well known to generate a large overhead frequency division duplex (FDD) mode as the amount of training generally scales with number transmit antennas. Using instead an extrapolation from measured uplink estimates downlink band completely removes this overhead. In paper, we investigate theoretical limits frequency. We highlight advantage basing on high-resolution estimation. A lower bound (LB) mean squared error (MSE) extrapolated...
Fifth generation mobile networks will be designed to utilize the benefits of large available bandwidth in mmWave spectrum. Commercialization 5G technology launched soon, due progress RF hardware and efforts on integration beamforming technologies standardization bodies such as 3GPP. The main challenges mobility result from impact fast-varying channels systems. However, corresponding feasibility has not yet been fully investigated. In this article we first identify review technical that...
Time-division multiplexed (TDM) channel sounders, in which a single RF chain is connected sequentially via an electronic switch to different elements of array, are widely used for the measurement double-directional/MIMO propagation channels. This paper investigates impact array switching patterns on accuracy parameter estimation multipath components (MPC) time-division sounder. The commonly-used sequential (uniform) pattern poses fundamental limit number antennas that TDM sounder can employ...
This paper presents results from channel sounding campaigns that investigate the impact of foliage blockage on wireless propagation characteristics at 28 GHz. The measurements are performed with a real-time sounder equipped phased array antennas allow beamforming and electronic beam steering for directionally resolved measurements. Thanks to short measurement time excellent phase stability system, we obtain both directional omnidirectional power delay profiles without any uncertainty. We...
This paper investigates the capability of millimeter-wave (mmWave) channel sounders with phased arrays to perform super-resolution parameter estimation, i.e., determine parameters multipath components (MPC), such as direction arrival and delay, resolution better than Fourier setup. We analyze question both generally, respect a particular novel multi-beam mmWave sounder that is capable performing multiple-input-multiple-output (MIMO) measurements in dynamic environments. firstly propose...
Vehicle-to-vehicle (V2V) wireless communication systems are fundamental in many intelligent transportation applications, e.g., traffic load control, driverless vehicle, and collision avoidance. Hence, developing appropriate V2V standardization require realistic propagation channel models. However, most existing modeling studies focus on car-to-car channels; only a few investigate truck-to-car (T2C) or truck-to-truck (T2T) channels. In this paper, hybrid geometry-based stochastic model (GBSM)...
Many wireless networks, including 5G NR (New Radio) and future beyond cellular systems, are expected to operate on multiple frequency bands. This paper considers the band assignment (BA) problem in dual-band where basestation (BS) chooses one of two available bands (centimeter-wave millimeter-wave bands) communicate with user equipment (UE). While might offer higher data rate, there is a significant probability outage during which communication should be carried (more reliable)...
This paper revisits the modeling of shadowing in urban microcells, putting particular emphasis on impact street canyons. We argue that a categoriztion links according to dominant propagation effects (line-of-sight, single diffraction, multiple diffraction) more accurately reproduces not only variance, but also autocorrelation behaviour. hypothesis is supported and quantified by ray launching simulations from downtown Los Angeles. A generic model simulation methodology are provided.