INEL 5995 Weather Radar Network Topics

Prof. Héctor Monroy

hmonroy@ece.uprm.edu

Of. S-413

¿Qué se estudia en esta parte del curso?

Cómo se transmiten los datos que toman los radares (tales como los de CASA), desde el sitio de cada radar hasta un centro de recolección de datos

Puerto Rico Student Test Bed (IP-3)

This slide is taken from a presentation by Brian C. Donovan, PhD Student UMass, Project ManagerApril 27, 2004

Mayagüez - Aguadilla 31.3 kmMayagüez – Isabela 35.0 kmAguadilla – Isabela 12.5 km

Node Spacing

Mayagüez - Aguadilla 31.3 kmMayagüez – Arecibo 50.7 kmAguadilla – Arecibo 42.0 km

Node Spacing

Location Possibilities. Slide taken from a presentation by Brian C. Location Possibilities. Slide taken from a presentation by Brian C. Donovan, PhD Student UMass, Project ManagerDonovan, PhD Student UMass, Project ManagerApril 27, 2004April 27, 2004

Ejemplo: Cómo traer al RUM Ejemplo: Cómo traer al RUM los datos colectados por un los datos colectados por un radar que se va a instalar radar que se va a instalar próximamente en la Finca la próximamente en la Finca la Montaña, Aguadilla, en el sitio Montaña, Aguadilla, en el sitio localizado enlocalizado en

18°28.465’ N, 67°07.267’ W18°28.465’ N, 67°07.267’ W

Proposed Location

Aguadilla(259’ over sea level)

This slide is taken This slide is taken from a presentation from a presentation by José Maeso by José Maeso and and Jorge M. TrabalJorge M. Trabal July 2004July 2004UPRMUPRM

Preguntas a responder inicialmente: ¿Qué vamos a transmitir? ¿Cómo lo vamos a transmitir? ¿Qué mecanismo de propagación debemos

Luego de responder lo anterior, se ataca el problema de cómo diseñar el sistema para transmitir los datos a un centro de recolección.

Alternativas para enviar los datos desde los radares al RUM:

Poner datos en Removable Disk y mandarlos con alguien (bueno…si no hay prisa).

Mandarlos vía Wired Network Mandarlos vía Wireless Network (si son

varios radares, podría ser conveniente tener un centro de recolección, y de ahí enviar todos los datos al RUM, todo vía wireless).

Conviene sabor algo sobre Types of Networks:

Private Networks http://www.stratexnet.com/products/

private_networks/Mobile Networks http://www.stratexnet.com/products/

mobile_networks/Fixed Networks http://www.stratexnet.com/products/

fixed_networks/

Tomado de los websites anteriores

PRIVATE NETWORKS Private networks employ a variety of applications. Utility

communications networks are a large user of microwave throughout the world, connecting oil and gas installations, pipelines, and even drilling platforms at sea. Campus-based university, health authority, and government networks are also an ideal application for microwave, providing connectivity between buildings that are co-located or distributed throughout a city or metropolitan area. These networks are self-contained, carrying PABX voice and LAN/WAN data traffic. National and regional TV networks also use microwave for contribution/distribution links between studios and broadcasting sites that are typically located on remote mountaintop locations where cable connectivity is impractical.

MOBILE NETWORKS

Microwave radio is the medium of choice for mobile infrastructures worldwide, providing a compelling backhaul solution for operators of Mobile Cellular Networks. The demand for microwave, driven in the 1990's by the expansion of GSM in Europe, is now set to be eclipsed by the 2002 rollout of 3G mobile networks. 3G technology combines the typical benefits of microwave radio, including cost-effective and rapid deployment, easy capacity upgrade, and minimal operational costs, with the ability for operators to establish and maintain their own transmission links, instead of leasing expensive circuits from local fixed-line operators.

FIXED NETWORS

A significant number of businesses remain disconnected from the information superhighway because they lack available wired broadband infrastructure. Wireless provides the perfect medium for breaking down the barriers of this "digital divide," whether in a city center or a remote rural community.

FIXED NETWORKS (cont.)

Networks' microwave radio systems enable transmission connections in places where fiber cannot reach, where build is prohibitively expensive, when local authorities refuse or inhibit right-of-way for cable deployments, as a wireless backup for critical fiber links, or for dedicated wireless last-mile access.

Wired and wireless networks Wired networks typically satisfy diverse requirements of different applications

using a single protocol. This means the most stringent requirements for all applications must be met simultaneously. Wired networks may have data rates of Gbps and BERs of 10-12.

Currently exists a tremendous infrastructure of wired networks: the telephone system, the Internet, fiber optic, cables . This infrastructure could be used to connect wireless systems together into a global network.

Wired networks are mostly designed according to a layered approach, whereby protocols associated with different layers of the system operation are designed in isolation, with baseline mechanisms to interface between layers.

The layered approach (layering methodology) of wired networks reduces complexity and facilitates modularity and standardization, but it also leads to inefficiency and performance loss, due to the lack of a global design optimization.

Wired and wireless networks (cont. 1)

The situation is very different in a wireless network due to the nature of radiopropagation and broadcasting.

The wireless network must be able to locate a given user wherever it is among billions of globally distributed terminals (if it is a mobile terminal, the system must route the signal to a user as it moves at a certain speed).

The layers in a wireless system include: the link or physical layer (handles bit transmission over the communications medium); the access layer (handles shared access to the communications medium); the network and transport layers (which route data across the network and ensure end-to-end connectivity and data delivery); and the application layer (dictates the end-to-end data rates and delay constraints associated with the application).

Wireless networks required integrated and adaptive protocols at all layers, from the link layer to the application layer.

Wired and wireless networks (cont. 2) The cross-layer protocol design of wireless networks requires

interdisciplinary expertise in communications, signal processing, and network theory and design.

Wireless networks, at least in the near future, will continue to be fragmented, with different protocols tailored to support the requirements of different applications. Wireless networks have much lower data rates and higher BERs.

Interfacing between wired and wireless networks with different performance capabilities is a difficult problem.

Since different wireless applications have different requirements

There are many ways to segment this topic into different applications, systems, and coverage regions.

This has resulted in considerable fragmentation in the industry.

There are many different products, standards, and services being offered or proposed.

See the 55 pages New American Public Knowledge (by Kevin Werbach).

Lectura recomendada (cultura general sobre telecomunicaciones, para el gran público)

Conviene también leer algo sobrePlanning Microwave Links. Ver, por ejemplo,

http://www.stratexnet.com/about_us/our_technology/files/planning_article/taju95.html

Ver también el website

BANDA ANCHA — DISPONIBILIDAD Y ACCESO.htm

Etapas de un diseño, desde el punto de vista de Comunicaciones: Circuitos y Antenas ( !OJO! Es diferente si se ve desde el punto de vista de Signal Processing o de Computer Science)

1- Identificar características y requisitos de los datos a ser transmitidos (R, B, BER, SNR, SINR, etc.).

2- Identificar rangos de frecuencia que se pueden usar (Recomendaciones y Normas ITU-R, FCC, IEEE).

3- Identificar posibles alternativas de transmisión, y escoger la mejor (enfatizaremos LOS, y algún stándard

IEEE802.11).

Etapas de un diseño, desde el punto de vista de Comunicaciones: Circuitos y Antenas (no de Signal Processing ni Computer Science) (cont. 1)

4- Analizar preliminarmente las posibles rutas de propagación (usar Google Earth, USGS).

5- Identificar las características generales de las posibles rutas de propagación (podrían usarse, por ejemplo, mapas de 1:25,000 de USGS en el Web).

6- Seleccionar la ruta más viable y obtener la base de datos topográficos (Digital Elevation Models, USGS).

7- Usar un software package (Radio Mobile, Radiosoft Comstudy, Planner, etc.) para analizar rutas y escoger alturas de antenas según requisitos de Zonas de Fresnel, reflexiones, etc.

8- Repetir paso anterior con diferentes condiciones atmosféricas (K = 5/3, 4/3, 1, 2/3). Escoger ruta y dismensionar preliminarmente el sistema (Tx, Rx, antenas, líneas, etc.).

9- Hacer pruebas de propagación (si hay los medios para tomar muestras), o usar Matlab para simular una señal recibida con los parámetros escogidos preliminarmente en el paso anterior.

10- Usar Gaussian distribution, y determinar mean, std, etc. de la señal simulada (o muestra recibida) para adecuar el sistema a la confiabilidad de operación especificada.

11- Usar Matlab para confirmar algunos resultados, haciendo el perfil topográfico de la ruta con la base de datos y simulando niveles de señal, de acuerdo al paso anterior.

12- Dimensionar de nuevo el sistema. !Tener en cuenta cálculos de SAR, aunque se use baja potencia!

13- Identificar proveedores de los equipos y componentes apropiados y hacer selección final del sistema, ajustado a los requisitos del diseño y a las Recomendaciones y Normas de ITU-R, FCC, IEEE, OSHA.

14- Hacer lista de equipos, antenas, torres, cables…y componentes necesarios para instalar el sistema.

15- Elaborar documento explicativo sobre las mediciones necesarias para optimizar el funcionamiento del sistema.

16- Hacer un Resumen Ejecutivo.

Detalles de las Etapas de Diseño (1)

1- Identificar características y requisitos de los datos a ser transmistidos ( R, B, BER, SNR, SINR, etc.).

-Application (Voice, sensing, file transfer, video teleconferencing, distributing control, paging and short messaging, Internet access, Web browsing, etc).

-Systems (cellular telephone, wireless LANs, wide area wireless data, satellite, ad hoc wireless netwoks).

-Coverage (building, city, regional, global).

See p. 5 Wireless Comm., A. Goldsmith, Cambridge, 2005.

Requirements for different applications make it difficult to build one system that can satisfy all requirements simultaneously.

Voice systems:

Have low data-rate requirements (around 20 kbps). Can tolerate high probability of bit error (BERs of around 10-3),

but The total delay must be less than 100 ms or else it becomes

noticeable to the end user (wired telephones have delay constraint of ≈30 ms, cellular phones ≈100 ms, voice over the Internet relaxes the constraint even further).

Data systems:

Typically require much higher data rates (1-100 Mbps).

Very small BERs (10-10 or less, and all bits received in error must be retransmitted).

Do not have a fixed delay requirement.

Real-time video systems:

Have high data-rate requirements coupled with the same delay constraints as voice systems.

Paging and short messaging:

Have very low data-rate requirements and no hard delay constraints.

Si queremos comunicar dos puntos del Oeste de PR…

2- Identificar rangos de frecuencia que se pueden usar (Recomendaciones y Normas ITU-R, FCC, IEEE).

The Electromagnetic Spectrum

4.1x10-15

1 Hz 1 kHz 1 MHz 1 GHz 1012 Hz 1015 Hz 1018 Hz 1021 Hz 1024 Hz 1027 Hz

3x108 3x105 3x102 3x10-1 3x10-4 3x10-7 3x10-10 3x10-13 3x10-16 3x10-19

NON-IONIZING RADIATION IONIZING RADIATION

RADIO FREQUENCY RADIATION

60 HzELECTRIC

AMRADIO

FMRADI

VISIBLELIGHT

MICROWAVES

INFRARED ULTRAVIOLET X-RAYS GAMMA COSMIC

WAVELENGTH (METERS)

FREQUENCY

4.1x10-6 eV

4.1x100 eV

4.1x1012 eV

ENERGY (ELECTRON VOLTS)

Hay que tener en cuenta las normas que rigen las telecomunicaciones A nivel mundial, las regulaciones las hace la Unión

Internacional de Telecomunicaciones http://www.itu.int/home/ y la IEEE recomiendahttp://www.ieee802.org/11/. Pero en todos los países hay agencias que regulan a

nivel nacional. Por ejemplo, en USA es la FCChttp://www.fcc.gov/.

Asignación: Visitar los sitios y aprender qué hace cada agencia. Tener en cuenta que algunas regulaciones de FCC, por ejemplo, están siendo cuestionadas. Las normas pueden variar ligeramente de un país a otro.

Will Changes toPart 15 of the FCC Rules & RegulationsEncourage Innovation?

Opinions of Members of the FCC Technological Advisory Council

Ver en sitio de WebCt

FCC Part_15_2_1_06.pdf,

Part_15_Survey.ppt

Un estándar de IEEE que ha revolucionado las telecomunicaciones (ver WebCt, documento 802_11tut.pdf)

Lectura recomendada: Unlicenced Wireless Broadband profiles (by Matt Barranca). Ver documento en WebCt, NewAmericanUnlicensed.pdf

El uso libre de bandas de frecuencia

3- Identificar alternativas de transmisión y mecanismos de propagación.

ACCESS SCHEMES

For radio systems there are two resources, frequency and time. Division by frequency, so that each pair of communicators is allocated part of the spectrum for all of the time, results in Frequency Division Multiple Access (FDMA). Division by time, so that each pair of communicators is allocated all (or at least a large part) of the spectrum for part of the time results in Time Division Multiple Access (TDMA). In Code Division Multiple Access (CDMA), every communicator will be allocated the entire spectrum all of the time. CDMA uses codes to identify connections.

http://www.umtsworld.com/technology/cdmabasics.htm

ACCESS SCHEMEShttp://www.umtsworld.com/technology/cdmabasics.htm

CODING

CDMA uses unique spreading codes to spread the baseband data before transmission. The signal is transmitted in a channel, which is below noise level. The receiver then uses a correlator to despread the wanted signal, which is passed through a narrow bandpass filter. Unwanted signals will not be despread and will not pass through the filter. Codes take the form of a carefully designed one/zero sequence produced at a much higher rate than that of the baseband data. The rate of a spreading code is referred to as chip rate rather than bit rate. See coding process page for more details.

CODING

POWER CONTROL

CDMA is interference limited multiple access system. Because all users transmit on the same frequency, internal interference generated by the system is the most significant factor in determining system capacity and call quality. The transmit power for each user must be reduced to limit interference, however, the power should be enough to maintain the required Eb/No (signal to noise ratio) for a satisfactory call quality. Maximum capacity is achieved when Eb/No of every user is at the minimum level needed for the acceptable channel performance. As the MS moves around, the RF environment continuously changes due to fast and slow fading, external interference, shadowing , and other factors. The aim of the dynamic power control is to limit transmitted power on both the links while maintaining link quality under all conditions. Additional advantages are longer mobile battery life and longer life span of BTS power amplifiersSee UMTS power control page for more details.

MULTIPATH AND RAKE RECEIVERS One of the main advantages of CDMA systems is the

capability of using signals that arrive in the receivers with different time delays. This phenomenon is called multipath. FDMA and TDMA, which are narrow band systems, cannot discriminate between the multipath arrivals, and resort to equalization to mitigate the negative effects of multipath. Due to its wide bandwidth and rake receivers, CDMA uses the multipath signals and combines them to make an even stronger signal at the receivers. CDMA subscriber units use rake receivers. This is essentially a set of several receivers. One of the receivers (fingers) constantly searches for different multipaths and feeds the information to the other three fingers. Each finger then demodulates the signal corresponding to a strong multipath. The results are then combined together to make the signal stronger.

Rangos de f (ELF, ULF,VLF, LF, MF, HF, VHF, UHF,

EHF…) y diferentes mecanismos de propagación.

LOS Surface wave Sky wave Troposcatter etc

4- Analizar preliminarmente las posibles rutas de propagación (usar Google Earth, USGS).

Ver WebCt, Google Earth

UPRM-UPRAguadillaGeographyU.S. Department of the Interior, U.S. Geological Survey, National Center, EROS || Not accurate for measurement purposes. || Visit us at http://gisdata.usgs.net

See Tutorial in http://seamless.usg.gov/Website/seamless/http://seamless.usg.gov/Website/seamless/viewer.php)viewer.php)

Western PR

Zoom to Area

XY Enter coordinates of points

Measure distance between points

Measure heights, do profile

Tener en cuenta que…

En los plots de USGS las distancias están en millas, y las alturas en metros o en píes.

Tener en cuenta las distancias entre los puntos (Ex. UPR Aguadilla-UPRM es de 17.34 millas, o 27.9 km).

Hay que medir individualmente las alturas de los puntos extremos (Ex. note que UPR Aguadilla está a 47 m sobre el nivel del mar, HASL=47m).

UPRM está a 119.337 m HASL. Estos datos servirán para constatar las alturas de los

puntos extremos. Hay que ser cuidadosos al colocar los extremos del plot en el mapa de USGS.

Note que las antenas estarán a cierta altura sobre el nivel de tierra (HAGL).

5 points plot…muy pocos datos

10 points plot…todavía muy pocos

20 points plot…tampoco, necesitamos al menos 100

5- Identificar las características principales de las rutas de propagación (podrían usarse mapas de escala 1:25,000 de USGS en el web).

Point 1: UPR-Aguadilla (18.46 N,- 67.11 W)Point 2: UPR-Mayagüez (18.21N,-67.13 W)

Distance: 17.34 miles(27.90 km) (50 points, using http://seamless.usg.gov/Website/seamless/viewer.php)

6- Seleccionar una ruta y obtener la base de datos topográficos (Digital Elevation Models, USGS).

Ejemplo de pequeño programita en Matlab para hacer un patrón de perfiles topográficos (demostrar cada término)

>> S=27.90; >> b=0.0589 >> D1=0:27.9/99:27.9; >> h1=b*(S-D1).*D1; >> y=[140 135 140 145 148 160 180

210 210…vector of 100 elements]; >> plot(D1,h1,D1,y)

m-file for plottingfunction testing1

b=0.0589;S=50;

D1=0:0.001:50;h1=b*(S-D1).*D1;

plot (D1,h1)hold

plot (D1,h1+50)hold on

0 5 10 15 20 25 300

Distance UPR Aguadilla-UPRM (km)

Distance=29.4km, K=4/3

!Ojo! Plot correcto, pero líneas horizontales incorrectas. Pasan cosas así cuando no se sabe en qué se basa el código.

0 5 10 15 20 250

UPR Aguadilla-UPRM Profile, K=4/3

Distance (km)

7- Usar un software package (Radio Mobile, Radiosoft Comstudy, Planner, etc.) para analizar rutas y escoger alturas de antenas según requisitos de Zonas de Fresnel, reflexiones, etc.

Software comercial para diseñar radio-enlaces(si se usa algo así, hay que entender de dónde viene cada cosa)

http://beradio.com/products/radio_radiosoft_comstudy/

Ver en WebCt RadioMobil.doc (direcciones para ver instrucciones sobre uso e instalación)

Coordenadas, Altura

Aguadilla

18.4606 N -67.11101W 133.353m

Mayaguez

18.21053N -67.13W 39.081m

Compare…calidades de las diferentes bases de datos

Atmospheric Effects

If the radio beam propagates in free space with NO ATMOSPHERE, the path is a straight line.

Through the earth’s atmosphere, variations in εr along the path causes the ray path to become curve.

Atmospheric gases absorb and scatter the radio path energy.

n = (εr )1/2 variations affect the curvature of the ray path.

Taken from R. Freeman, Radio System for Telecommunications, Wiley 2002

Fresnel zone problem (Taken from R. Freeman, Radio System for Telecommunications, Wiley 2002)

Taken from R. Freeman, Radio System for Telecommunications, Wiley 2002Taken from R. Freeman, Radio System for Telecommunications, Wiley 2002

Ground Reflection

Radio waves reflected from the earth’s surface are generally changed in phase depending on the polarization and the angle of incidence.

Horizontally polarized waves are shifted ≈180o (path length changes ≈ λ/2).The resulting reflections may arrive out of phase with the direct wave.

For vertical pol. phase, shift varies between 0- 180o, depending on the reflection coeff.

Tower heights can be adjusted to move the reflection to a convenient point.

Fading

Defined as any time varying of phase, polarization, and/or RSL.

The definitions are in terms of refraction, reflection, diffraction, scattering, attenuation, and guiding (ducting) of the radio wave.

The terms determine the statistical behavior of fields level, phase, polarization, frequency and spatial selectivity of the fading.

Fading is caused by certain terrain geometry and meteorological conditions.

All communication systems in the 1-100GHz range can suffer fading, including satellite earth terminals operating at low elevation angles and/or in heavy precipitation.

Multipath Fading

Is the most common type of fading encountered on LOS radiolinks. Could be particularly troublesome on high-bit-rate LOS links.

As n = (εr )1/2 changes, multipath fading results owing to the interference between direct rays and ground-reflected wave, or reflections from atmospheric sheets, or other reflections.

The fading rate (number of fades/time), and the fading depth (variation of RSL from its free space value in db) are important factors for design engineers.

Fade can exceed 20db on longer LOS paths.

Power Fading

Results from a shift of the beam from the receiving antenna due to one or several of the following:

-intrusion of earth’s surface or atmospheric layers into the path.

-antenna decoupling due to K-factor variations.

-partial reflections from elevated layers.

-one of the antennas in a ducting formation.

-rain in the propagation path.

Fading due to Earth bulge

If K < 1 (sub-refractive), power fading depths of 20-30db for several hours or more may be expected owing to the diffraction by the earth’s surface.

This type of fading may not be normally mitigated by freq. diversity.

It may be reduced or completely avoided by the proper adjustment of antenna tower heights. Clearances greater than one Fresnel zone may be required (one Fresnel zone in mountainous regions)!

Some other factors of fading

K-Factor Fading Surface Duct Fading on Over-Water

Paths Duct and layer fading

Taken from R. Freeman, Radio System for Telecommunications, Wiley 2002Taken from R. Freeman, Radio System for Telecommunications, Wiley 2002

Taken from

www.umtsworld.com/technology/cdmabasics.htm

8- Repetir el paso anterior con diferentes condiciones atmosféricas (K = 5/3, 4/3, 1, 2/3). Escoger la ruta y seleccionar preliminarmente el sistema (Tx, Rx, antenas, líneas, etc.).

El paso anterior es 7- Usar un software package (Radio Mobile, Radiosoft Comstudy,

Planner, etc.) para analizar rutas y escoger alturas de antenas según requisitos de Zonas de Fresnel, reflexiones, etc.

Una fórmula para ser demostrada y discutida en detalle (path calculations)

Pt db = - 171.5 + 20.log fMHz + 20.log rkm +

10.log RHz + (Eb/N0)db + NFdb +

- GT db - GR db + LT db + LR db

+ Aa db

Tener cuidado con el uso de calculadoras…Si no se entienden las fórmulas, puede haber sorpresas

Distance Aguadilla- Mayaguez is 27.9 km (17.3 miles) True North Azimuth = 184.1°, Magnetic North Azimuth = 196.2°, Elevation angle = -0.4015° Terrain elevation variation is 222.5 m

Distance Mayaguez-Aguadilla is 27.9 km (17.3 miles) True North Azimuth = 4.1°, Magnetic North Azimuth = 16.2°, Elevation angle = 0.1507° Terrain elevation variation is 222.5 m

Transmitter (Aguadilla):Tx Power=10w (40dBm), Gt=5dBi (2.85dBd), Lt=1dBEIRP= 25.12W, ERP= 15.32W, ht=240m

2400MHz ≤ f ≤2406MHz

Receiver (Mayagüez): Required E field = 31.33dBµ/m, Gr=5dBi (2.85dBd), Lr=1dBRx sensitivity = 0.75µV ( -109.5dBm), hr=200m

Azimuth= 184.10, Elev.angle=-0.4010 , Clearance at 16.57km, Worst Fresnel=3.01F1, r=27.86kmPathLoss=127.3dB, E=61.5dBµV/m (at Rx antenna), Rx level=-79.3dBmRx level=24.15µV, Rx relative = 30.2dB!Note que las alturas de las torres son absurdas!

Distance between Aguadilla and Mayaguez is 27.9 km (17.3 miles)

True North Azimuth = 184.1°, Magnetic North Azimuth = 196.2°, Elevation angle = -0.4015°

Terrain elevation variation is 222.5 m Propagation mode is line-of-sight, minimum clearance

3.0F1 at 16.6km Average frequency is 2403.000 MHz Free Space = 128.9 dB, Obstruction = -2.8 dB, Urban = 0.0

dB, Forest = 0.0 dB, Statistics = 1.2 dB Total propagation loss is 127.3 dB System gain from Aguadilla to Mayaguez is 157.5 dB System gain from Mayaguez to Aguadilla is 157.5 dB Worst reception is 30.2 dB over the required signal to meet 50.000% of time, 50.000% of locations, and 50.000% of

situations

9- Hacer pruebas de propagación (si hay los medios para tomar muestras), o usar Matlab para simular una señal recibida con los parámetros escogidos preliminarmente en el paso anterior.

Muestra tomada…o simulada, si no hay manera de hacer pruebas de propagación

0 200 400 600 800 1000 1200 1400 1600 1800 2000

10- Usar Gaussian distribution, y determinar mean, std, etc. de la señal simulada (o muestra recibida) para adecuar el sistema a la confiabilidad de operación especificada.

11- Usar Matlab para comparar algunos resultados, haciendo el perfil con la base de datos topográficos y observando niveles de señal (reales o simulados), de acuerdo al paso anterior.

Radio Mobile for Windows Version 7.1 Name AguadillaAntenna height 240(m) Name MayaguezAntenna height 200(m)Frequency 2.403(GHz)Earth curvature factor K = 1.33331675899808

Distance(km) Elevation(m) PathLoss(dB) 0000.000 0133.4 0 0 000.0 0000.377 0135.0 0 0 000.0 0000.753 0143.7 0 0 095.3 0001.130 0148.7 0 0 104.2 0001.506 0152.6 0 0 102.7 0001.883 0163.1 0 0 109.9 0002.259 0174.3 0 0 106.6 0002.636 0187.8 0 0 109.4 0003.012 0194.8 0 0 108.1 0003.389 0211.8 0 0 109.2 0003.765 0226.1 0 0 110.1 0004.142 0232.5 0 0 111.3 0004.518 0237.4 0 0 112.0 0004.895 0231.3 0 0 115.4 0005.271 0227.6 0 0 113.6 0005.648 0200.8 0 0 119.2 0006.024 0129.8 0 0 114.2 0006.401 0087.6 0 0 118.8 0006.777 0048.2 0 0 117.4 0007.154 0041.7 0 0 115.8 0007.530 0036.2 0 0 119.9 0007.907 0053.1 0 0 120.0 0008.283 0050.8 0 0 121.1 0008.660 0031.0 0 0 117.4 0009.036 0029.8 0 0 118.7 0009.413 0027.1 0 0 119.1 0009.789 0037.5 0 0 118.7 0010.166 0038.2 0 0 119.1 0010.542 0073.7 0 0 123.9 0010.919 0098.7 0 0 121.9 0011.295 0082.8 0 0 121.9 0011.672 0118.4 0 0 120.0 0012.048 0122.5 0 0 121.0 0012.425 0163.6 0 0 120.8 0012.801 0156.8 0 0 120.8 0013.178 0116.4 0 0 121.0 0013.554 0114.9 0 0 121.8 0013.931 0122.2 0 0 125.8 0014.307 0141.7 0 0 122.5 0014.684 0169.2 0 0 122.4 0015.060 0174.6 0 0 122.2

Observe como fluctúa la atenuación (cerca de r=0 hay indeterminación)

12- Dimensionar de nuevo el sistema, con base en los resultados de los dos pasos anteriores.

!Tener en cuenta cálculos de SAR, aunque se use baja potencia!

Fundamental information regarding human interaction with electromagnetic radiation, covering several aspects of incident and internal field dosimetry, thermal body response, biological effects, measurement techniques and safety standards regarding the possible radiation hazard with reference to the existing limits.

International Commission on Non-Ionizing Radiation Protection (ICNIRP)

Guidelines for human exposure limits.

Human Exposure to Electromagnetic Fields

Conviene saber la diferencia entre Ionizing vs. Non-Ionizing Radiation, aunque las ondas EM usadas aquí no son de frecuencias ionizantes

ENERGY= f * hWhere h=Plancks constant

= 6.63 x 10-34 joule seconds f = frequency

The higher the frequency, the higher the energy

Ionizing vs. Non-Ionizing Radiation

At a frequency of approx. 2.420x106 GHz the energy level is sufficient to ionize water molecules.

Therefore, frequencies at or above this level are classified as “Ionizing”

Efectos de la Radiación Ionizante Un rayo X de 3x1018Hz tiene fotones con energía dehf=(6.626x10-34).(3x1018)=1.878x10-16Jouls, que equivale a 12.4KeV. En el rango UV, una onda de 2.42x1015Hz tiene

fotones de 10eV.Para ionizar un átomo se requiere que el fotón que

choca con el electrón tenga energía por lo menos igual a la que lo mantiene ligado al núcleo.

Efectos de la rad. Ioniz. (cont.)

Material Energía Ionizante Hidrógeno 13.6eV

Sodio gaseoso 5.1eV Agua 12.4eV12.4eV son suficientes para ionizar una molécula de agua. Una

onda de f>1015Hz es radiación ionizante. La energía de un fotón en particular es muy pequeña, pero el número de fotones en un haz de moderada intensidad es enorme. La ionización produce profundos cambios químicos que pueden ser irreversibles.

Energía de los fotones de algunos servicios de RF

TV de UHF de 700MHz 2.88x10-6 eV Radar de microondas de 10GHz 4.12x10-5 eV Onda milimétrica de 300GHz 1.24x10-3 eV Luz visible de 6x105 GHz 2.47 eV

Comparar con

Radiación UV de 10x107 GHz 41.2 eV

Rayos X blandos de 109 GHz 4120.0 eV

Rayos X duros de 1012 GHz 4.120x105 eV

Pero la radiación no-ionizante también puede ser muy peligrosa

Las ondas de RF pueden producir vibraciones y oscilaciones rotacionales en las moléculas, que se traducen en calentamiento y otros efectos.

Esto puede dar lugar a cambios drásticos en las substancias orgánicas e inorgánicas.

Maximum Limits of Average Power from Man-made sources

Frequency 0.01 0.1 1 10 100 1000 GHz

Solid State

Avalanche diode

GriddedTube

MicrowaveTubes

CyclotronTubes

Power Output Levels

Firefly (0.0005 W)

Door Opener (0.005 W)

Police Radar (0.015 W)

Childrens Walkie-Talkie (0.15W)

Cellular Phone (0.6W)

Microwave Radiation by Humans (3.5W)

C.B. Radio (5W)

Mobile Radio (50W)

Microwave Oven (800W)

AM/FM Transmitter 5-50 kW)

UHF Transmitter (120 kW)

RF Energy and the Human Body

There are many factors that affect absorption into the human bodyDielectric CompositionSize of the BodyShape, Orientation and PolarizationComplexity of the RF field

1. Dielectric Composition

(ver, por ejemplo, Ishimaru, EM Wave Propagation, Prentice Hall,

Since the human body has a different dielectric constant (Є) than free space, field measurements are performed where the front surface of the body would be.

RF energy typically passes through the fatty tissue and is deposited in the muscle or brain tissues.

Penetration Depth vs. Frequencyvs. Different tissues (cm’s)

0.1 1.0 100.3 3.0 GHz

Penetration depth vs. Frequency

10 100 1000 10,000MHz

1000 100 10 in cm.

2. Size of the Body

There are different absorption characteristics based on the size of the body and the wavelength

• A. > The body In this region, there is little absorption and a uniform or equal distribution of energy. The impedance of the body increases as the wavelength increased. Safety standards are based on shock or burn hazards rather than direct absorption.

2. Size of the Body (Cont’d)

~ = The Body In this region, the absorption is highest and the energy is distributed unequally. Hot spots may be generated.

< The Body Lower absorption of energy and heating confined to irradiated area.

RF Absorption vs. Frequency

Frequency

E - Polarization

H - Polarization

K - Polarization

SAR Induced in a 1.75mhigh Human Exposed to1 mW/cm2 RF Field

Antenna

Radiation

10 30 100 300 1 3 10 30 100

(MHz) (GHz)

RF Absorption vs. Frequency

Upper Limit SAR for the range of human beings from infant to adult

Numerical Calculationsbased on a block modelof man in conductivecontact with ground

One year old childin conductivecontact with ground

Prolate model ofa human infant

Frequency (MHz)10 30 60 100 300 600 1000

3. Shape, Orientation and Polarization

The Human body in a vertical position absorbs 10 times more energy in a vertically vs. horizontally polarized emission.RF energy can be focused in common,

workplace environments. Reflective environments (screen rooms, sides of buildings, etc.) can enhance the fields in certain conditions.

4. Complexity of the Fields

Most all standards are based on the far field relationships and their interaction with the body.

Near field exposures are difficult to measure and almost impossible to calculate.

Combined with the three previous factors determining absorption, the total variables become staggering.

Non-thermal Effects

Many have been postulated, but none have been proven

Melatonin suppression is an effect that is not completely understood.

GSM phones under evaluation because of modulation phenomena.

Cellular Phone Studies

RF Exposure in the vicinity of portable communication devicesUsually antennas have cylindrical symmetryPower density is not a meaningful parameterThe exposed body may cause a substantial

alteration of the RF source characteristicsThe exposed body and the antenna become

practically one source of RF fields

12- Identificar proveedores de los equipos y componentes apropiados y hacer selección final del sistema, ajustado a los requisitos del diseño y a las recomendaciones y normas de ITU-R, FCC, IEEE.

Ejemplo de proveedor: www.freewave.com/

Hyperlink 2.4 GHz, 24 dBi Antenna

N-Male Connector, 0.25 dB loss

Times Microwave Systems

LMR-400 Coax Cable TTX13 / VTX13 Transmitter TRX23/VRX23 Receiver

Cisco Aironet 350 Wireless Bridge

Proxim Orinoco Wireless PC Card Laptop (Linux)

ReceptorTRX Series

L-3 Telemetry West

Receptor

TTX13 SeriesL-3 Telemetry West

Transmisor

Elaborar documentos:

Lista de equipos, antenas, cables, torres,…y componentes necesarios para instalar el sistema.

Especificar mediciones requeridas para optimizar el sistema y mantener operativo su funcionamiento.

Spectrum Analyzer

Measurements:Noise FloorBandwidthNoise FigurePeak PowerGain 1dB Compression Point

Noise Figure (NF)Noise Figure Measurement Setup:

RF Noise Source Pre Amplifier

Power Supply @ 4.5 VSpectrum Analyzer

1dB Compression Point Measure of what is less than expected by 1dB (saturation)

Determine the utility of an amplifier

Measure linearity

Determine Dynamic Range (region of operation)

1 dB Compression Point1 dB Compression Point Setup:

Pre Amplifier

Power Supply @ 4.5 V

RF Signal Generator

Spectrum Analyzer

Network Analyzer

S Parameters of an RF/Microwave Device

Transmission (S12, S21)

Reflection (S11, S22)

Impedance (Matching)

VSWR Verify Bandwidth Resonant Frequencies

Wilkinson Power Divider

Detalles de las Etapas de Diseño

13- Identificar proveedores de los equipos y componentes apropiados y hacer selección final del sistema, ajustado a los requisitos del diseño y a las Recomendaciones y Normas de ITU-R, FCC, IEEE, OSHA.

14- Hacer lista de equipos, antenas, torres, cables…y componentes necesarios para instalar el sistema.

15- Elaborar documento explicativo sobre las mediciones necesarias para optimizar el funcionamiento del sistema.

16- Hacer un Resumen Ejecutivo.

!Si…este es el último slide!

Gracias por su atención a esta parte del curso

INEL 5995 Weather Radar Network Topics

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