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pierredv : propagation   47

A New Wireless Communication Paradigm through Software-Controlled Metasurfaces - IEEE Journals & Magazine
Via Marina Petrova May 2019

Electromagnetic waves undergo multiple uncontrollable alterations as they propagate within a wireless environment. Free space path loss, signal absorption, as well as reflections, refractions, and diffractions caused by physical objects within the environment highly affect the performance of wireless communications. Currently, such effects are intractable to account for and are treated as probabilistic factors. This article proposes a radically different approach, enabling deterministic, programmable control over the behavior of wireless environments. The key enabler is the so-called HyperSurface tile, a novel class of planar meta-materials that can interact with impinging electromagnetic waves in a controlled manner. The HyperSurface tiles can effectively re-engineer electromagnetic waves, including steering toward any desired direction, full absorption, polarization manipulation, and more. Multiple tiles are employed to coat objects such as walls, furniture, and overall, any objects in indoor and outdoor environments. An external software service calculates and deploys the optimal interaction types per tile to best fit the needs of communicating devices. Evaluation via simulations highlights the potential of the new concept.
propagation  metamaterials  nanomaterials  wireless 
may 2019 by pierredv
mmWave 5G real-world deployments will require very dense networks: report | FierceWireless apr 2019
"Moore conducted his tests using the Motorola Z3 handset with the 5G Moto Mod adapter. Verizon gave him a list of nine cells, and he tested about six of them while walking around Chicago.

Moore said he received a top speed of 500 Mbps during his tests. “It’s very zippy under favorable conditions with line of sight,” he said, but added that mmWave doesn’t penetrate obstacles and it doesn’t travel far."

“Moore said he tested the signal speed through a pane of glass in a restaurant that was only about 25 yards away from a cell node. “I found that the speeds were roughly halved from what I was getting outside on the street,” he said. The initial real-world 5G network tests make clear the 5G networks that use mmWave spectrum will face a lot of challenges. “It requires a very, very dense network,” Moore said.”
FierceWireless  propagation  mmwave  5G 
april 2019 by pierredv
Line of Sight – What’s wrong with Gigabit wireless access? (Reality Check) Jan 2018
Via Dale Hatfield
"Spoiler Alert: Obstructions."

"Access-industry veterans have seen and participated in a variety of attempts at wireless fixed broadband access over the years, and they know several key challenges must be overcome for new wireless solutions to meet the real-world demands of gigabit access in the general copper-replacement case. Many of these challenges — spectral efficiency, interference management, continuous adaptation to changing conditions, uniform service delivery throughout coverage areas, and stable, deterministic performance — follow directly from the first and most prominent issue on the list: obstructions."

"Tarana’s Residential LoS Availability study took the industry’s first careful look at the fixed wireless access obstruction challenges in residential neighborhoods."
5G  broadband  RCRWireless  Tarana  propagation  opinion  mmWave 
january 2018 by pierredv
PROPA : Dynamic Link Library Propagation

via Chip Fleming

tropospheric P.618-9, P.840-4 Propagation losses Dynamic Link Library (DLL) for calculation of propagation losses for Earth to space (or space to Earth) transmission links



La Dynamic Link Library (DLL) Propagation contient des fonctions de calcul de pertes de propagation suivant les algorithmes recommandés par l'Union Internationale des Télécommunications
propagation  satellite  ITU-R 
november 2017 by pierredv
Google and other databases likely to make spectrum sharing easier | FierceWireless
"Sharing spectrum is likely to get a whole lot easier thanks to the databases that Google and others are creating that show where nearly every building and tree in populated areas is located. This leads to better propagation models that show where available spectrum is located and where it can be shared."

Andy Clegg: “If you want to provide point-to-multipoint services, satellites could stay in the band but if you want to open it to mobile, you most likely would have to clear the satellite interests out of the band”
FierceWireless  mirror-worlds  SAS  CBRS  database  propagation 
october 2017 by pierredv
P.618 : Propagation data and prediction methods required for the design of Earth-space telecommunication systems
P.618 : Propagation data and prediction methods required for the design of Earth-space telecommunication systems
ITU-R  ITU  propagation  satellite  space 
august 2017 by pierredv
Software, Data and Validation examples for ionospheric and tropospheric propagation and radio noise
Software, Data and Validation examples for ionospheric and tropospheric propagation and radio noise

Via Chip Fleming, FCC
ITU  ITU-R  propagation 
july 2017 by pierredv
ITS Releases Key Software Model to Boost Collaborative Spectrum-Sharing Research | NTIA
The source code posted by ITS is a "reference implementation" of the Extended-Hata Urban Propagation Model (eHata), which was created to predict propagation of new commercial broadband services proposed to share the 3.5 GHz band with Navy radars. Those predictions enabled regulators to significantly expand commercial access to the 3.5 GHz band through the establishment of the Citizens Broadband Radio Service.
ITS  NTIA  propagation  Hata 
may 2017 by pierredv
TVStudy Interference Analysis Software | Federal Communications Commission
"The FCC’s Office of Engineering and Technology (OET) has released software, called TVStudy, which interfaces with data contained in FCC Media Bureau’s CDBS/LMS databases and is used to perform coverage and interference analyses of full service digital and Class A television stations. TVStudy software is provided for both Mac and Linux platforms with Java and C source code freely available under a BSD (Berkley Software Distribution) license. The software was initially developed for use in the broadcast television incentive auction for evaluating the coverage areas and population served for television stations in the United States. The version used for all calculations related to the incentive auction is version 1.3.2, which remains available on the OET–69 TVStudy page. Newer versions of TVStudy intended for use related to transitional issues after conclusion of the incentive auction will appear on this page."
FCC  TV  interference  propagation 
march 2016 by pierredv
Fix coming for Lancaster County's interference-plagued 911 radio system | Local News |
via Dale "The broadcast signal from a TV station in Arlington, Virginia more than 100 miles away continues to disrupt some emergency radio dispatches in Lancaster County, but a fix is on the way. About 5,800 radios of first responders in coming weeks will be reprogrammed with new frequencies that won't be susceptible to interference from the WFDC tower in Arlington or any another signal, said Michael Weaver, director of Lancaster County-Wide Communications. The weather-influenced interference has bedeviled Lancaster County's dispatches ever since the transition last year to a $26.4-million digital radio system for police, firefighters, medics and county workers. "
911  interference  public-safety  propagation  ducting 
march 2016 by pierredv
Radio Mobile - RF propagation simulation software - Welcome
"Radio Mobile is software by Roger Coudé VE2DBE. The program simulates RF propagation and is for free to the amateur radio community."
radio  propagation  simulation  modeling 
june 2015 by pierredv
4 Fading, Shadowing, and Link Budgets
"Fading is a significant part of any wireless communication design and is important to predict. There are two very different types of fading: small scale fading and large scale shadowing. Small scale fading is often handled in a wireless system with diversity schemes, redundancy, or even retransmit. Large scale shadowing on the other hand is very dependent on location with respect to obstacles, and cannot always be fixed; its modeling consists in predicting the likelihood of outage. We review in this chapter various fading models, we examine how they impact wireless links and how they are modeled in various standards link budgets."
RF  tutorial  fading  shadowing  link-budget  propagation  * 
may 2015 by pierredv
Ofcom | BBC/Ofcom DAB In-home Reception Trial
"the project obtained DAB reception measurements within households located in a number of pre-selected coverage areas in order to determine how well the model’s predicted level of coverage matched measured levels of coverage. . . The findings of the two phases of this study confirm that == on average the Prediction Model gives a good indication of the level of DAB coverage and == DAB reception in ‘good’ DAB coverage areas is equivalent to good FM reception"
Ofcom  measurement  modeling  prediction  propagation  BBC  DAB 
january 2015 by pierredv
Dominant Path Model
See also for Intelligent Ray Tracing "Ray-optical propagation models are still very time-consuming – even with accelerations like preprocessing. And what is even more important, they rely on a very accurate vector database. Small errors in the database influence the quality of the prediction. On the other hand, empirical models are – for example- based on dedicated propagation effects like the over-rooftop propagation (COST 231) or on other pre-defined scenarios. As a consequence of these restrictions, a new Propagation Model has been developed, the Dominant Path Prediction Model."
propagation  RF  dominant  path  model  DPM 
june 2014 by pierredv
Sprint may need up to 40,000 new cell sites for 2.5 GHz, tower exec says - FierceWirelessTech May 2014
"Sprint (NYSE: S) will need to roll out an additional 30,000-40,000 transmission sites if the carrier wants its 2.5 GHz TD-LTE network to reach coverage parity with its 1.9 GHz networks, according to the head of American Tower."
Sprint  FierceWireless  propagation  2.5GHz  1.9GHz  LTE  TD-LTE 
may 2014 by pierredv
CEPT.ORG - ECO - Tools and Services - SEAMCAT
SEAMCAT is a software tool based on the Monte-Carlo simulation method, which is developed within the frame of European Conference of Postal and Telecommunication administrations (CEPT). This tool permits statistical modelling of different radio interference scenarios for performing sharing and compatibility studies between radiocommunications systems (short range devices, GSM, UMTS, LTE, etc… ) in the same or adjacent frequency bands.
propagation  interference  modeling  CEPT  SEAMCAT  ECO 
november 2013 by pierredv
FM and TV Propagation Curves Graphs - Sections 73.333, 73.525, and 73.699 |
"The table below contains graphical implementations of the FM and TV propagation curves graphs contained in Sections 73.333 and 73.699 of the FCC's rules. We include F(50,90) digital television service graphs, although these are not in the FCC's rules. Lastly, we provide Figures 1 and 2 from Section 73.599 of the interference ratio curves from FM noncommercial educational stations to TV Channel 6 stations. "
propagation  contours  TV  regulations  FCC 
october 2012 by pierredv
Your DTV Assignment - Does it provide optimum coverage (PDF) Weller 1998
Discussion of methods of assigning DTV coverage based on NTSC Grade B, part of debate during introduction of DTV. Includes discussion of errors in Longley-Rice, as used by FCC to calculate replication contours
propagation  coverage  DTV  spectrum  FCC 
october 2012 by pierredv
Antenna Patterns and Their Meaning [Cisco Aironet Antennas and Accessories] - Cisco Systems
Much can be learned about how an antenna performs from its patterns. This paper describes many of the common antenna parameters that can be understood from the patterns.
propagation  x:cisco  spectrum  wireless  antennas 
july 2012 by pierredv
Irregular Terrain Model (ITM) (Longley-Rice) - source page NTIA/ITS
The ITS model of radio propagation for frequencies between 20 MHz and 20 GHz (the Longley-Rice model) (named for Anita Longley & Phil Rice, 1968) is a general purpose model that can be applied to a large variety of engineering problems. The model, which is based on electromagnetic theory and on statistical analyses of both terrain features and radio measurements, predicts the median attenuation of a radio signal as a function of distance and the variability of the signal in time and in space.
radio  propagation  propagationmodel  ITM  simulation  longley-rice 
july 2012 by pierredv
FCC Defines DTV ‘City Grade’ Contour - May 2001 - Doug Lung in TV Technology
"How do you define DTV coverage? Since 1997 the FCC has defined it as the 41 dBu F(50/90) contour for UHF stations, 36 dBu for Channels 7-13 and 28 dBu for Channels 2-6. In a Report and Order released earlier this year, the FCC defined a "City Grade" DTV field strength contour and also set minimum signal levels for reception of broadcast DTV signals at cable headends.

This month I’ll explain the FCC’s new coverage definitions and present some tables to allow you to easily see what kind of coverage can be expected from a DTV facility."
TV  FCC  propagation  RF 
june 2012 by pierredv
Radio propagation models (Harvard course material)
Radio Propagation Models


Path Loss: models of "large-scale effects"
Free space loss
Plane earth loss, ground reflections
Micro-Cellular, indoor channels
Shadowing, joint effect of multiple interferers.
Multipath: Rician and Rayleigh fading
Doppler spectrum, rate of fading, random FM
Threshold crossing rate TCR and average fade duration AFD
Delay spread and coherence bandwidth
Scatter function
Reciprocity of uplink and downlink
Appendix 1: Antenna Fundamentals
RF  propagation  tutorial  * 
june 2012 by pierredv
Propagation Loss Calculator
For seven different propagation models, this calculator gives the propagation loss in dB for the distance in kilometers that is entered by the user. The calculation also is a function of frequency and antenna heights, and the user may enter values for these parameters. The models for calculating the propagation loss that are included are

the CCIR model, taking the parameter "percentage of buildings"
four cases of the Hata model that correspond respectively to "open", "suburban", "small city", and "large city" terrain
two cases of the Walfisch-Ikegami model that correspond respectively to line-of-sight (LOS) and non-LOS situations and that take parameters that describe the building heights, street width, etc.
The calculator was originally developed as an Excel spreadsheet application by Leonard Miller. New C++ and TCL pop-up versions were developed by Tim Hall, as was a command-line executable file that can be run in a DOS window.
propagation  NIST  spectrum  RF 
june 2012 by pierredv
DAS In Action: 'Green' buildings at odds with RF propagation - RCR Wireless News
"Green building designs are good for the environment and benefit society, but they can wreak havoc on cellular signals, panelists agreed during an educational session that was part of PCIA's DAS Forum “DAS In Action: Capital View” event here earlier this week."
rcrwireless  wireless  propagation  ecology 
june 2011 by pierredv
UMTS900 - benefits and issues (PDF) Ovum
"UMTS900 provides between 44% (in urban areas) and 119% (rural areas) increased coverage per Node-B compared with UMTS2100"
cellular  propagation  wireless  ovum  filetype:pdf  media:document 
june 2009 by pierredv
Wide-Range Propagation Model Final Report (Year 1) | Ofcom
a study to develop a new propagation model that will predict coverage of and interference between radio networks over a wide range of time percentages
ofcom  propagation  radio  wireless 
may 2009 by pierredv
NTIA - Microcomputer Spectrum Analysis Models (MSAM)
installable Longley-Rice (aka Irregular Terrain Model) calculator
NTIA  wireless  spectrum  modeling  propagation  rf  engineering 
january 2008 by pierredv

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