A5044163630- Advanced MIMO Systems Optimization
- Advanced Wireless Communication Techniques
- Millimeter-Wave Propagation and Modeling
- Wireless Communication Networks Research
- Cooperative Communication and Network Coding
- Antenna Design and Analysis
- Microwave Engineering and Waveguides
- Power Line Communications and Noise
- Advanced Wireless Network Optimization
- PAPR reduction in OFDM
- Energy Harvesting in Wireless Networks
- Telecommunications and Broadcasting Technologies
- Direction-of-Arrival Estimation Techniques
- Advanced Adaptive Filtering Techniques
- Radio Frequency Integrated Circuit Design
- Indoor and Outdoor Localization Technologies
- Parallel Computing and Optimization Techniques
- Interconnection Networks and Systems
- Blind Source Separation Techniques
- Advanced Power Amplifier Design
- Security and Verification in Computing
- Crime Patterns and Interventions
- Speech and Audio Processing
- Antenna Design and Optimization
- Advancements in Photolithography Techniques
University of California, Berkeley
2021-2024
University of Washington
2015-2018
National Instruments (Ireland)
2016
Qualcomm (United Kingdom)
2016
New York University
2016
Aalborg University
2014-2016
Aalborg Portland (Denmark)
2016
Qualcomm (United States)
2016
Nokia (United States)
2013-2016
L-3 Communications (United States)
2016
Recently, there has been considerable interest in new tiered network cellular architectures, which would likely use many more cell sites than found today. Two major challenges will be i) providing backhaul to all of these cells and ii) finding efficient techniques leverage higher frequency bands for mobile access backhaul. This paper proposes the outdoor millimeter wave communications networking between within a cell. To overcome impairments propagation, this studies beamforming using large...
The proliferation of internet-connected mobile devices will continue to drive growth in data traffic an exponential fashion, forcing network operators dramatically increase the capacity their networks. To do this cost-effectively, a paradigm shift cellular infrastructure deployment is occurring away from traditional (expensive) high-power tower-mounted base stations and towards heterogeneous elements. Examples elements include microcells, picocells, femtocells, distributed antenna systems...
Wireless data traffic is projected to skyrocket 10 000 fold within the next 20 years. To tackle this incredible increase in wireless traffic, a first approach further improve spectrally efficient systems such as 4G LTE bands below 6 GHz by using more advanced spectral efficiency techniques. However, required substantial system complexity along with fundamental limits on hardware implementation and channel conditions may limit viability of approach. Furthermore, end result would be an...
compared to the four-parameter ABG model.Results show CI model with a 1-m reference distance is suitable for outdoor environments, while CIF more appropriate indoor modeling.The and models are easily implemented in existing 3GPP by making very subtle modification-by replacing floating non-physically based constant frequency-dependent that represents free-space path loss first meter of propagation.This paper shows this change does not mathematical form ITU/3GPP offers much easier analysis,...
For the development of new 5G systems to operate in bands up 100 GHz, there is a need for accurate radio propagation models at these that currently are not addressed by existing channel developed below 6 GHz. This document presents preliminary overview These have been derived based on extensive measurement and ray tracing results across multitude frequencies from GHz this describes an initial 3D model which includes: 1) typical deployment scenarios urban microcells (UMi) macrocells (UMa), 2)...
This paper presents and compares two candidate large-scale propagation path loss models, the alpha-beta-gamma (ABG) model close-in (CI) free space reference distance model, for design of fifth generation (5G) wireless communication systems in urban micro- macro-cellular scenarios. Comparisons are made using data obtained from 20 measurement campaigns or ray- tracing studies 2 GHz to 73.5 over distances ranging 5 m 1429 m. The results show that one-parameter CI has a very similar goodness fit...
Multi-antenna technologies such as beamforming and Multiple-Input, Multiple-Output (MIMO) are anticipated to play a key role in "5G" systems, which expected be deployed the year 2020 beyond. With class of 5G systems both cm-wave (3-30 GHz) mm-wave (30-300 bands, unique characteristics challenges those bands have prompted revisiting design performance tradeoffs associated with existing multi-antenna techniques order determine preferred framework for deploying MIMO technology systems. In this...
There is growing interest in using millimeter wave (mmWave) frequencies for future access communications based on the enormous amount of available spectrum. To characterize mmWave channel urban areas, wideband propagation measurements at 73 GHz have recently been made New York City. Using measurements, a ray-tracing study has conducted databases same environments as allowing simple ray-tracer to predict measured statistics such path loss and angles arrival physical environment measurements....
A 2D antenna array introduces a new level of control and additional degrees freedom in multiple-input-multiple-output (MIMO) systems particularly for the so-called "massive MIMO" systems. To accurately assess performance gains these large arrays, existing azimuth-only channel models have been extended to handle 3D channels by modeling both elevation azimuth dimensions. In this paper, we study correlation matrix generic ray-based model, our analysis simulation results demonstrate that can be...
This paper presents key parameters including the line-of-sight (LOS) probability, large-scale path loss, and shadow fading models for design of future fifth generation (5G) wireless communication systems in urban macro- cellular (UMa) scenarios, using data obtained from propagation measurements at 38 GHz Austin, US, 2, 10, 18, 28 Aalborg, Denmark. A comparison different LOS probability is performed Aalborg environment. Alpha-beta-gamma close-in reference distance loss are studied depth to...
Future mobile communications systems are likely to be very different those of today with new service innovations driven by increasing data traffic demand, processing power smart devices and innovative applications.To meet these demands the telecommunications industry is converging on a common set 5G requirements which includes network speeds as high 10 Gbps, cell edge rate greater than 100 Mbps, latency less 1 msec.To reach looking at spectrum bands in range up GHz where there availability...
To meet the explosive growth in traffic during next twenty years, 5G systems using local area networks need to be developed. These will comprise of small cells and use extreme cell densification. The millimeter wave (Mmwave) frequencies, particular from 20 GHz 90 GHz, revolutionize wireless communications given amount available bandwidth. However, different propagation conditions hardware constraints Mmwave (e.g., RF beamforming with very large arrays) require reconsidering modulation...
Multi-antenna techniques capable of exploiting the elevation dimension are anticipated to be an important air-interface enhancement targeted handle expected growth in mobile traffic. In order enable development and evaluation such multi-antenna techniques, 3rd Generation Partnership Project (3GPP) has recently developed a three-dimensional (3D) channel model. The existing two-dimensional (2D) models do not capture characteristics, making them insufficient for studies. This article describes...
In the past decade, large scale mobile phone data have become available for study of human movement patterns. These hold an immense promise understanding behavior on a vast scale, and with precision accuracy never before possible censuses, surveys or other existing collection techniques. There is already significant body literature that has made key inroads into mobility using this exciting new source, there been several different measures used. However, based are inconsistent, inaccurate,...
Bolstered by the ever increasing processing power of smart devices and combined with new innovative applications, cellular data traffic demand is expected to increase a 10000x 2025. Simultaneously, telecommunication industry converging on common set 5G requirements specifying 10x peak rates, reductions in latency 100x increases cell edge rates over 4G cellular. Researchers are now looking higher frequencies meet achieve requirements. This paper describes an experimental system designed...
Availability of large untapped spectrum resources in the millimeter wave (Mmwave) band is suitable for providing a gigabit experience with true local feel using high capacity small cells. Unlike traditional cellular systems, transmissions do not benefit from diffraction and dispersion making it difficult them to propagate around obstacles thus resulting higher shadowing loss. They also have less favorable link budgets due lower power amplifier (PA) output powers greater pathloss at these...
Due to the projected increased demand for high data rate mobile services, interest has grown in new cellular network architectures such as a tiered networks. This paper proposes beam searching algorithm and codebook design multilevel beamforming outdoor millimeter wave communication systems. In an scenario, received signal suffers from severe path loss various attenuation factors. Beamforming is essential component establish wireless link 60GHz up 80GHz. A method based on joint...
This paper describes a novel type of single-carrier DS-CDMA system that combines the use OFDM-style cyclic prefixes with frequency-domain equalization, for on forward link broadband CDMA cellular systems. The proposed method is referred to as CP-CDMA. combination and MMSE equalization solves many performance complexity problems arise in receivers when techniques such multi-level modulation full code usage are employed. Simulation results presented 20 MHz these compared conventional either...
It is becoming clear that 5G wireless systems will encompass frequencies from around 500 MHz all the way to 100 GHz. To adequately assess performance of in these different bands, path loss (PL) models need be developed across this wide frequency range. The PL can roughly broken into two categories, ones have some anchor physics, and curve- match only over data set without any physical anchor. In paper we use both real-world measurements 2 28 GHz ray-tracing studies 73.5 GHz, an urban-macro...
This paper compares three candidate large-scale propagation path loss models for use over the entire microwave and millimeter-wave (mmWave) radio spectrum: alpha-beta-gamma (ABG) model, close-in (CI) free space reference distance CI model with a frequency-weighted exponent (CIF). Each of these have been recently studied in standards bodies such as 3GPP, design fifth generation (5G) wireless systems urban macrocell, microcell, indoor office shopping mall scenarios. Here we compare accuracy...
Fifth-generation wireless systems are expected to employ multiple-antenna communication at millimeter wave (mmWave) frequencies using small cells within heterogeneous cellular networks. The high path loss of mmWave and the physical obstructions make challenging. To compensate for severe loss, may a beam alignment algorithm that facilitates highly directional transmission by aligning direction multiple antenna arrays. This paper discusses system employing dual-polarized antennas. First, we...
The coronavirus pandemic precipitated an economic crisis disproportionately affecting renter households. Attempting to prevent a surge in evictions, policy makers at the federal, state, and local levels extended emergency protections renters. authors describe eviction filing patterns 2020 analyze efficacy of moratoria. New filings were reduced dramatically since start pandemic. Between March 15 December 31, 2020, across sites for which data are available, 65 percent fewer cases filed than...
Eviction is one of the most pressing challenges facing millions households today, particularly in urban areas, with filings expected to rebound or even surpass pre-pandemic levels. While non-payment rent frequently cited as primary reason for eviction, underlying causes have not been thoroughly examined. This study analyzes eviction court files from 2014 2017, obtained Pierce County, Washington, and applies advanced data science techniques, including layout analysis natural language...
Massive multiple-input multiple-output (MIMO) systems can attain a high channel capacity and spectral efficiency by using very large antenna array at the base station (BS). However, cost of having one radio frequency (RF) chain behind every element be prohibitive. In addition, overall power consumption RF hardware excessively high. A hybrid analog-digital structure utilized to reduce required number chains BS. this paper, we present achievable rates beamforming in multi-user MIMO (MU-MIMO)...