LOS line of sight lecture 1

LOS 9/22/2012 4:40 PM

JBC © 1982 1

JBCardenas © 1982

JBC © 1982~2012 Telecommunications

JBCardenas © 1982

Line of Sight

Sources:Personal College Notes; lectures of Engr. Conrad Hernandez, ect…Roelofs, Stan, "Fade Margin Requirements for Microwave Systems", Microwave Reference Guide, 1986, Motorola.

Engineering Considerations for Microwave Communications Systems, 1975, GTE Lenkurt Incorporated.

Examples from ELE 511 Lecture of Dr. Thomas Afullo, Department of Electrical Engineering, University of Botswana, Gaborone, Botswana, 2000(?)

Microwave Radio Link Design, Florio Fabbri, Teletra SpA, 1965Stephen Harsany, Principles of Microwave Communications, Prentice Hall, 1997

Anton Huurdeman, Radio Relay Systems, Artec House, 1995Wayne Tomasi, Electronics Communication System: Fundamental thru Advance, 5th ed, Prentice Hall, 2004

Digital Microwave Systems Application Seminar, HARRIS, Issue: Vol 1: Link Engineering issue 16, Vol 2 Equipment System Engineering issue 17, March 2006

Radio Mobile

LOS1

Introduction rev A2.07

Design Requirements 1 2

� Definitions� Microwave Spectrum� Earth Bulge� F-Zones� k Factor� Reflection Point� Diffraction� Attenuation� Site and Frequency Selection� LOS Path Design

Considerations� Equipment Considerations� Transmission Calculations� Diversity and Protection Copy of presentation materials, not

a stand-alone lecture note2012 © Jose Cardenas, v A3.00

Copy of presentation materials, not a stand-alone lecture note

2012 © Jose Cardenas, v A3.00

JBC © 1982-2007 v A2.08 Telecommunications 2

JBCardenas © 1982

Line of Sight – Radio Link Systems

LOS1

• Radio link engineering involves the following:– Selection of terminal and repeater sites;– Selection of an operational frequency

band; establishment of frequency plan;– Development of path profiles to determine

radio tower heights;– Path calculations and determination of

antenna and equipment specification;– Path survey.

• Line-of-sight (LOS) radio link systems are widely deployed as broadband transmission medium commonly used to transport the analogue FDM/FM or digital PCM/PSK SDH/QAM baseband systems.

• We define radiolink systems as those that fulfill the following requirements:– Signals follow a straight or line-of-sight (LOS) path– Signal propagation is affected by free-space attenuation and

precipitation– Use of frequencies greater than 150 MHz, thereby permitting the

transmission of more information per RF carrier by use of wider information baseband

– Use of angle modulation, digital modulation, or spread-spectrum techniques.

Base A

Base C

Base E

Relay B

Relay DSPUR

BACKBONE

Base A

Base C

Base E

Relay B

Relay DSPUR

BACKBONE

Backbone carries traffic for more than a pair.

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JBCardenas © 1982

Introductory TerminologiesBER bit error rate or bit error ratioCrosslink direct radio or optical connection between satellitesDuplexer separates transmit from receive when using the same antennaEb energy per bit = signal power consumed as it was propagated to the receiving end.Elevation angle horizontal to point in the center of main beam when antenna is pointed directly to satellite or

another stationBrewster angle no reflection occurs in medium of origin sin B =sin-1 √ ( 1 / ( 1 + 2 ))EIRP effective isotropic radiated power - this represents the power signal as it leaves the microwave

antenna itself; It is the power of the signal as it leaves and travels in airFootprint depiction of signal strength contours on earthFading reduction of signal strength due to reflection and absorptionFM fade marginFrequency diversity use of 2 or more RF channels to transmit informationFSL is defines as the loss that would be obtained between two isotropic antennas in free space,

where there are no ground influences or obstructionsIRL isotropic receive level = signal power as it reaches the antenna of the second site.Isotropic radiator antenna that radiates equally in all directionLow Earth Orbit orbits at an altitude < 1,500 km; orbital period approx 1.5 hrs; visibility approx 0.25 hrsMRS median receive signalMedium Earth Orbit orbits between 8,000~17,000 km; period 6~12 hrs; visibility 2~4 hrsNFdBW relates the signal to noise ratio of the output signal from the network to the signal to noise ratio

of the input signalNO thermal noise = random current variations in every portion of the electronic equipmentRake receiver combining several received signals with different time delays into one composite signalRSL receive signal level = sum of the IRL, the gain of the antenna and the line lossSpatial diversity use of 2 or more physically separated antennas at one end of the communication linkTracking continuous adjusting of directional antenna so that it always points at the satelliteTranslation Freq Conversion frequency at the satellite between transmit & receive frequenciesTransponder a repeater or communication channel located on a satelliteVan Allen Belt radiation belts at 1,000~5,000 km, and 17,000~20,000 km.

SatCommA

LOS1SATCOM1


JBCardenas © 1982

More DefinitionsThe Receiver Sensitivity Threshold (Rx) defines the minimum signal strength required in order for

a radio to successfully receive a signal. A radio cannot receive or interpret a signal that is weaker than the receiver sensitivity threshold.

The Receive Signal Level (RSL) is the expected strength of a signal when it reaches the receiving radio. The following formula defines the Receive Signal Level: Po - Lctx + Gatx - Lcrx + Gatx - FSL = RSL. Synonymous to Median Received Signal (MRS).

Fade Margin is the difference between the unfaded Receive Signal Level and the Receiver Sensitivity Threshold. Fade Margin is the link’s insurance against unexpected system outages.

A Path Profile is a graphical representation of the path traveled by the radio waves between the two ends of a link. The Path Profile determines the location and height of the antenna at each end of the link, and it insures that the link is free of obstructions, such as hills, and not subject to propagation losses from radio phenomena, such as multipath reflections.

Multipath Distortion is due to difference in arrival time because of multiple paths.

Oceanic Wireless Troposcatter (1968) and LOS (1985) Stations @ Vigan

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JBCardenas © 1982

Microwave Bands

56+ ~ 100W5.20+ ~ 10.9X

46+ ~ 56V1.55+ ~ 5.20S

36+ ~ 46Q0.39+ ~ 1.55L

10.9+ ~ 36.00K0.255 ~ 0.39P

GhzDesignationGhzDesignation

Frequency Range: ( 0.255 Ghz ∼ 300 Ghz )1969 Manufacturers P L S C X K Q V W1970 US Military A B C D E F G H I J K L M N1980 Vendors P L S X K Q V W1989 IEEE L S C X Ku K Ka1997 FCC Bulletin 70: Q 33-50 Ghz, V 50-75 Ghz, etc..

“C“ band includes Sz to Xy or 3.9 ∼∼∼∼ 6.2, or 4~8 per IEEE (1989)“K1” band includes Ku to Kq or 15.35 – 24.50, or 12~40 per IEEEISM for unlicensed Industrial, Scientific and Medical band, includes BluetoothU-NII for unlicensed national info infrastructure, 300Mhz band at 5Ghzz, ect…

“C“ band includes Sz to Xy or 3.9 ∼∼∼∼ 6.2, or 4~8 per IEEE (1989)“K1” band includes Ku to Kq or 15.35 – 24.50, or 12~40 per IEEEISM for unlicensed Industrial, Scientific and Medical band, includes BluetoothU-NII for unlicensed national info infrastructure, 300Mhz band at 5Ghzz, ect…

Radar Bands

Satellite BandsL 1~2GhzS 2.01~4C 4.01~8X 8.01~12Ku 12.01~18K 18.01~27Ka 27.01~40

uWaves Master


JBCardenas © 1982

Characteristics of MicrowavesPropagation options: Line of Sight

�Direct

� Reflected

� Diffracted

� ScatteredFor long distances, earth curvature is

pronounced.For long distances, earth curvature is

pronounced.

uWaves Master

� Line of Sight� NLOS w/ multi path

� tropo ducting� billboards� ionospheric refraction

� knife edge

� Tropospheric� Rain

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JBCardenas © 1982

Jose B. Cardenas, C.P.M. EE, ECE

LOS Design Considerations

• To determine the tower height, we must establish the position and height of obstacles in the path between stations with which we want to communicate by radio link; fresnel zones need to be considered as well

• To each obstacle, we shall add the earth bulge: this is the number of meters an obstacle is raised higher (into the path) owing to earth’s curvature.

• We also incorporate the fact that the ray path is curved (rather than straight); atmospheric refraction may cause the ray beam to be bent toward the earth or away from the earth. If the ray is bent toward the earth, it is as if we shrank the earth budge; and if the beam bent away from the earth, it is as if we expanded the earth budge or raised it toward the beam above its true value.

• This lowering or raising is handled mathematically by using the k- factor.

• Radio waves traveling through the atmosphere do not follow true straight lines. They are refracted or bent.

• If radio waves above 100 MHz traveled a straight line, the engineering of LOS microwave links would be much easier. We could then accurately predict the height of towers at repeater and terminal stations, and exactly where the antenna should be placed on the tower.

Problem: Compute earth bulge midway & tower heights of NY and London.

Use r = 6084 kmk = 1

Some references: r = 6437


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Earth Bulge

• The earth bulge (at a point P, d1 km from A, and d2 km from B) then becomes:

• The k-factor can be calculated from the formula:

• One value commonly used for r0 is 6084 km; then we calculate the effective earth radius, r, from the formula:

• Where Ns is the surface refractivity. This is the refractivity at the altitude of the LOS microwave sight that was selected, or the average refractivity of the path.

)()()(,078.0)( 2121 kmdkmdkmDwhere

Kddmh +==

0rr

radiusearthtrueradiuseartheffective

K ==

[ ]sNerr 005577.00

04665.01−=

LOS1 Lecture

Earth bulge computation

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JBCardenas © 1982

k

• The sea-level refractivity, No, can often be obtained for the area from a nearby weather bureau. If No is known, then the surface refractivity can be obtained as:

• Where hs is the altitude above sea level (in km) of the LOS radio site.• If the K-factor is greater than 1 (K>1), the ray beam is bent toward the earth,

which essentially allows us to shorten radio-link towers.• If K<1, the earth bulge is effectively increased, and the path is shortened or

the tower height must be increased.• Many radio links refer to the standard atmosphere with K=4/3; and therefore

profile charts have been developed for K=4/3. This is USA standard, in the Philippines certain researches indicate 2/3 instead.

• However, care should be taken when engineering radio links that the K=4/3 (or 2/3) theory may only be used for gross planning; in reality, it is important to determine the average and effective K-factors for the hop for adequate path engineering. For classroom design work, I shall give further instructions on what k factor to use.

shs eNN 1057.0

0−=

Equivalent Earth Radius Factor “k” also represents Boltzmann’s constant, wave number and code or frequency reuse number.“k” also represents Boltzmann’s constant, wave number and code or frequency reuse number.

Jose B. Cardenas, C.P.M. EE, ECE


JBCardenas © 1982

Characteristics of Microwaves

r = 3781 mi or 6084 km, others, e.g.: 6370 km also used.

a = k x r

k = 1 / (( 1 + (a/n) (dn/dh )).

Supernormal STD Ideal Average Subnormal Difficult

K ∞∞∞∞ 4/3 1 3/4 2/3 5/12Terrain “parallel” rocky/dry agricultural valley/highly-irrigated H2O

Equivalent Earth Radius Factor

� Attenuated� Refracted� Interference

r

LOS1

INTERMEDIATE VALUES

Refraction in the lower layers of the atmosphere is one of the effective mechanisms that cause microwave signals to penetrate into the geometrical shadow zone over a spherical Earth. If the vertical gradient of the index of refraction n at the Earth's surface is sufficiently large, signals may be trapped and channeled in a surface troposphere waveguide. This elevated refractive layer is also known as M-inversion. For the LOS lecture, we shall consider only direct propagation and how refraction affects it.

The radio refractive index of the atmosphere is governed by the combination of atmospheric temperature, pressure and humidity. Over oceans particularly, humidity gradients can cause an effect known as the evaporation duct. Such a duct has the property of trapping radio waves between the sea surface and the top of the duct, which can result in extended range or radio black spots. In the LOS lecture, we shall consider only the k-factor.

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JBCardenas © 1982

Fre(s)nel Zone

• Another factor that must be added to the obstacle to obtain an effective obstacle height is the Fresnel clearance.

• The amount of additional clearance that must be allowed to avoidproblems with diffraction phenomenon in electromagnetic wave propagation theory is expressed in Fresnel zones.

• The radius of the first Fresnel zone, Rm (or ho),in meters, at a point P, d1 km from A, and d2 km from B, is given by:

• Where f is the propagation frequency in GHz.• It is generally accepted that most of the worthwhile energy transmitted

between transmitter and receiver is contained within the first Fresnel zone; and therefore clearance of this zone is important in the design of LOS radio links.

• However, it has also been determined that optimum clearance of an obstacle is accepted as clearance of 60% of the first Fresnel zone radius.

fDddRm 213.17=

Fresnel Zones


JBCardenas © 1982

Propagation options: LOS

� Direct

� Reflected� Ionospheric refraction� Tropospheric ducting� Billboards


Vector formulas: R = z d1(θ1) d2(θ2), E = Eo(1+Re -j2π ( /λ)), = (2h1’h2’)/d

Values of reflection factor

Values of Rho

water

rice field

agricultural

city, forest

2 Ghz 1 0.8 0.6 0.3

4 Ghz 1 0.8 0.5 0.2

6 Ghz 1 0.8 0.5 0.2

11 Ghz 1 0.8 0.4 0.16

uWaves

Reflected multipath

Faded path

Different lossDifferent delay

Brewster angle – no reflection in the medium of the origin

sin = √ (e1/(e1+e2))Note: other than an option can also be a nuisance.

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JBCardenas © 1982


JBCardenas © 1982

B

C

AZ

dr1 dr2

hr

R

h2

D

y

x

ββββ1111

ββββ2222

90 − β90 − β90 − β90 − β 1111

90 − β90 − β90 − β90 − β 2222

φφφφA φφφφB

φφφφC

θθθθ1111

θθθθ2222

Reflection Point

• From the profile, possible reflection points may be obtained.• The objective is to adjust the tower heights such that the relevant reflection

point is adjusted to fall on land area where the reflected energy will be broken up and scattered.

• Bodies of water and other smooth surfaces cause reflections that are undesirable. The objective is to ensure that such terrain are avoided, and the reflection point falls on wooded areas, hilly areas, etc.

• By adjusting the ratio of tower heights, h1/h2, the reflection point can be moved, in accordance with given tables or computationally.

• For a highly reflective path, space diversity may be desirable to minimize the effects of multipath reception.

• Diversity reception tends to reduce depth of fades on a combined output.• Diversity reception is based on the fact that the radio signal arriving at a point

of reception over separate paths may have uncorrelated signal levels. That is, while at one instant of time a signal on one path may be in condition of fade, the identical signal on another path may not.

• One of the main attractions of space diversity if that no additional frequency assignment is required, and the vertical separation of the antennas optimized, the two 180 0 out of phase then keep T.L. equal in electrical length.

The reflected ray might not exist but there is always one reflection point!The reflected ray might not exist but there is always one reflection point!


JBCardenas © 1982

Alpha, Beta & Theta Computation

where:ro = true earth radius (3781 miles = 6084 km), in kmk = earth radius factor (actual)R = effective earth radius (km)D = great circle length (km)dr1, dr2 = great circle distance from the point of reflection

to the site (km)h1, h2 = antenna height plus elevation of the site (m)hr = elevation at the point of reflection (m)

B

C

AZ

dr1 dr2

hr

R

h2

D

y

x

ββββ1111

ββββ2222

90 − β90 − β90 − β90 − β 1111

90 − β90 − β90 − β90 − β 2222

φφφφA φφφφB

φφφφC

θθθθ1111

θθθθ2222

D(km) = 111.69 √ ( 1/K [ (( θ2 - θ1 )/K)2 + { (ϕ2 - ϕ1) cos ((θ1+θ2) / 2 )}2 ] ) K = 1 - 0.00674 cos 2 ( θ2 + θ1) / 2where: θ is longitude, ϕ is latitude, and site 1 is lower than site 2.

Great Circle Simplified Formulas (for quizzes only):

α1 = α0 - αsα2 = α0 + αs + 180α0 = tan -1 ( cos (( θ2 + θ1 ) / 2 ) X ( ϕ2 - ϕ1 ) / ( θ2 - θ1) )αs = 1/2 sin (( θ2 - θ1 ) / 2 X ( ϕ2 - ϕ1 )

β1 (deg) = 0.0573 { (h2 - h1 ) / D - 4 / 51 · D / k }

θ1 (deg) = 0.0573 [ ( h1 - hr ) /dr1 + ( h2 - h1 ) / D - 4 / 51 · ( D - dr1 ) / k ]

θ -- has 2 meanings

Precision required: xx ˚ xx xx.xx ˝Precision required: xx ˚ xx xx.xx ˝

LOS1

K -- has 2 meanings

Research: 2, 2, etc…Research: 2, 2, etc…

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JBCardenas © 1982

Antenna Height Optimization

Unobstructed signal

ho = hc and reflected signal obstructedMany possible combinations of antenna heights; one solution for antenna of equal heights. Reflected signal is obstructed.

ho = hc at two highest obstructions. Only one possible set of optimum antenna heights that exactly clears the 1st Fresnel zones. Best strategy.

Many possible antenna heights, some pairs result to signal cancellation. Only onereflection point for a given set of antenna heights. Choose shortest towers, make sure signals do not cancel.

LOS1 Lecture

With or without potential obstructionWith one antenna at a given height, there is a range of heights possible for the other site. Not the best design, make sure signals do not cancel.Jose B. Cardenas, C.P.M. EE, ECE

1800 phase shift

hC = 0.6hO


JBCardenas © 1982

Propagation options: Quasi-optical sight

� Direct

� Reflected

�Diffracted

� Scattered


“Broadgauge” (for exam purposes) loss:• Knife Edge: 6.9 dB (some books 6)• Wedge: 7~20 dB• Spherical: 20 dBMore precise values are obtained by

various graphs and charts

� also, due to gravity!

uWaves

higher freq

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JBCardenas © 1982

Diffraction and Obstruction ConsiderationsAttenuation due to diffraction from an obstruction may be approximated using the following formula,

and also according to some

Lateral obstruction also possible!Lateral obstruction also possible!

A = 6.9 + 20log[√√√√ (v2+1) - v]

h

A = 16 + 20log[ h/ho ]

USE THIS

v


JBCardenas © 1982

Propagation options: Transhorizon

� Direct

� Reflected

� Diffracted

� Scattered� Tropospheric� Rain


Troposphere

Approx 35,000 ft

warm air

tropospheric ducting

uWaves Master

typically 30Mhz-5Ghz

eb((m) = 0.078 d1(km) d2(km) / keb((m) = 0.078 d1(km) d2(km) / k

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JBCardenas © 1982

Troposcatter LinksAir density decreases with height, and reaches one-third of its sea level value at about 30,000 ft. The refractive index of the atmosphere depends on such properties as temperature, density (pressure), humidity or the presence of water. Variations in any of these properties can scatter the signals. The scattering process is more efficient at lower altitudes where the atmosphere is denser. Turbulence associated with the weather can have marked effects on the signal levels and characteristics. In practice, this mechanism is used by pointing both antennas along the great circle path between the two stations at as low an angle of elevation as possible. The two beams will intersect in a common volume of the atmosphere near the center of the path.

Propagation will be line-of-sight to the common volume from the transmitter. A very small fraction of the Power passing through this volume will then be scattered in all directions by the irregularities in the atmosphere. Some of this power then propagates by line-of-sight to the receiver. The height of the bottom of this scattering volume will depend on the path length, and to some extent on the horizons of the sites, but will be typically 2000 ft on a 60-mile path, and 30,000 ft on a 300-mile path. The loss in the scattering process is usually so large that the equipment is unlikely to have enough spare capability to overcome the extra losses introduced by any additional obstructions in the path.

θθθθ = ( 2D-d1-d2)/2R + (h2-h1)/d1 + (h4-h3)/d2θθθθ = ( 2D-d1-d2)/2R + (h2-h1)/d1 + (h4-h3)/d2


JBCardenas © 1982

Troposcatter Design Considerations

Buckingham station @ VirginiaAcehigh Station, L band c 1981

The procedure for designing a tropospheric scatter propagation system is substantially similar to that adopted for direct path LOS terrestrial links, differing in that the auxiliary losses due to propagation through the shadow zone must be added. Both short and long term fading must be considered. Slow fading due to variability of k, thus independent of frequency; fast fading due to atmospheric multipaths. Another consideration is propagation delay and its effect on bandwidth. To compensate for the strong attenuation, high gain antennas are used, taking into account decreasing antenna gain due to coupling withmedium (presence of atmosphere). Pictures of some troposcatterstations are shown below.

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JBCardenas © 1982

Other Atmospheric MechanismsP H Y S I C A L M E C H A N I S M

S C A L E R E G I O N S H E I G H T O F O C C U R E N C E

M O D E L S

R a d i a t i v e h e a t i n g

M e s o / m a c r o L a n d , d e s e r t S u r f a c e –t h o u s a n d s o f f e e t

N u m e r i c a l w e a t h e r m o d e l s

R a d i a t i v e c o o l i n g

M e s o / m a c r o D e s e r t , d r y –i n l a n d , p r a i r i e

S u r f a c e –h u n d r e d s o f f e e t

N u m e r i c a l –a n a l y t i c a l w e a t h e r m o d e l s

e v a p o r a t i o n m a c r o s e a S u r f a c e – 2 0 0 f e e t

E m p i r i c a l m o d e l s ; d a t a b a s e s

a d v e c t i o n m e s o C o a s t a l , l a n d & s e a

H u n d r e d s –t h o u s a n d s o f f e e t

C i r c u l a t i o n m o d e l s , n u m e r i c a l w e a t h e r m o d e l s

s u b s i d e n c e m e s o C o a s t a l , s e a T h o u s a n d s o f f e e t


s u b s i d e n c e m a c r o L a n d a n d s e a T h o u s a n d s o f f e e t , B o u n d a r y l a y e r & a b o v e


F r o n t a l s y s t e m m e s o L a n d a n d s e a H u n d r e d s –t h o u s a n d s o f f e e t


U p p e r – a i r t u r b u l e n c e

m a c r o L a n d a n d s e a T h o u s a n d s & t e n s o f t h o u s a n d s o f f e e t

D i r e c t m e a s u r e m e n t s o f t u r b u l e n c e


JBCardenas © 1982

Evaporative Ducting• Propagation speed of sea breeze front depends on

large scale forcing• Sea breeze extension depends on large off shore

wind component• Onset of sea breeze depends on solar radiation

available• Development of sea breeze depends also on the

prevailing winds.• Duct formation; high level elevated, lower level,

stronger elevated duct, surface duct.• Evaporation duct gets stronger as wind speed

increases in the surface layer.• Complex refractivity structure ranging from sub –

refractive over land to elevated ducts, surface ducts and “nested” ducts over the sea.

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JBCardenas © 1982

M Profiles

Problem: Find the range of 1st Fresnel zone radii midpoint of an 80 km hop operating at P-band.

Solution: P band has wavelengths that ranges roughly 76.872 cm to 133.3 cm. Midpoint is 40 km.

163.28225.06133.3Upper limit123.99390.2676.872Lower limitho (mtrs)f (Mhz)λλλλ (cm)

Remove cover for solution before printing

Fun Time


JBCardenas © 1982

Another Look @ Free Space Loss

• Consider a signal traveling between transmitter Tx and receiver Rx.• The distance between Tx and Rx is D and the frequency of transmission is f. If D is in

km and f is in MHz, the free-space loss, L, in decibels, can be calculated as:

• For example, if D=40 km, and f=6 GHz, the FSL becomes 140 dB.

D

fDLdB log20log2044.32 ++=

� Attenuated� Refracted� Interference

Tx Rx

Attenuation at 24 Ghz

Typical Hop Lengths (US FCC)2110 to 2180 MHz 5 km (3.1 miles)3700 to 4200 MHz 17 km (10.56 miles)5925 to 6425 MHz 17 km (10.56 miles)10,700 to 11,700 MHz 5 km (3.1 miles)@ Reliability and BER are the criteria

FSL = 92.40 + 20 log (km) + 20 log (Ghz)= 32.44 + 20 log (km) + 20 log (Mhz)

f

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JBCardenas © 1982

Other Considerations

� Antenna and repeaters� Antenna sub-system

� Pressurization� Antenna tower and mast� Sub-station design� No-break (power) system� Channel and frequency

assignments

JBC © 2004 Design Samplers

JBCardenas© 1 982

Sample: LOS Design, 3Q03041st HOP: San Fern an do, L a Union to Caba, La Union

0

50

100

150

200

250

300

0 2 4 6 8 10 12 14 16 18 20

D ISTANCE IN KILOMETERS

ELEVATION IN METER

S

eb total elevation LOS H1-up H1-down ----reflec ted signal

2nd HOP : Caba, La Union to Pugo, La U nion

0

50

100

150

200

250

300

350

0 2 4 6 8 10 12 14 16 18 20 22 24

DISTANCE IN KILOMETERS

ELEV

ATION IN ME

TERS

eb total elevation LOS H1-up H1-down ----reflec ted signal

3rd HOP: Pugo, La U nion to Malasiq ui, Pangasinan

0

50

100

150

200

250

300

350

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38

DISTANCE IN K ILOMETERS

ELEVAT

ION IN ME

TERS

eb total elevation LOS H 1-up H1-down ----reflected s ignal

Design a LOS system from Subic to SFU.Design a LOS system from Subic to SFU.

another solution

R1: Relay site selection R4: Single-hop reliabilityR2: Path Profile, one hop R5: Complete report w/R3: Gain-loss computations BOM, ant layout, etc..

Relay Station Antenna height exactly 100 ft.

samples

LOS3 Lecture

Research Work� Design Tools� Standards� NTC Requirements� Zoning/Local

Requirements.


JBCardenas © 1982

Business Application

Backbone P2P Link

Can be Wave or FOC

• Types of LOS System– Terrestrial Microwave / P2P– Troposcatter and Diffraction Links– Fixed Wireless Point to Multi-point– Satellite Applications– Cellular Communication, BTS-BSC– (Mobile Applications)

RITL

LOS1

Documents

LOS line of sight lecture 1