005 - introduction to microwave links (asiacell telecom platform course)
TRANSCRIPT
Introduction to Microwave Links
Asiacell Telecom Platform Course 1
Introduction to Microwave Links
By [email protected] Engineer Specialist
Introduction to Microwave Links
Asiacell Telecom Platform Course 2
Micro...wave... link?
Introduction to Microwave Links
Asiacell Telecom Platform Course 3
Introduction toMicrowave
Links
Introduction to Microwave Links
Asiacell Telecom Platform Course 4
To describe microwave link architectures.
To define wavelength.
To define polarizations.
To describe propagation in free space.
To list propagation problems.
To list the characteristics of an antenna.
To identify the types of modulation.
To list parameters for preparing a frequency plan.
To prepare a simplified link budget.
To describe the configurations of a transceiver.
Objectives
Introduction to Microwave Links
Asiacell Telecom Platform Course 5
Microwave link architectures
Signals to be transmitted
Definition
Architectures
Radio waves
Definition
Polarization
Propagation in free space
Propagation problems
Antennas
Gain
Radiation pattern
Aperture angle
Modulation
Frequency plan
Organizations
Plan
Link budget
Transceiver hardware configurations
Course content
Introduction to Microwave Links
Asiacell Telecom Platform Course 6
Microwave link architectures
Signals to be transmitted
Definition
Architectures
Radio waves
Definition
Polarization
Propagation in free space
Propagation problems
Antennas
Gain
Radiation pattern
Aperture angle
Modulation
Frequency plan
Organizations
Plan
Link budget
Transceiver hardware configurations
Course content
Introduction to Microwave Links
Asiacell Telecom Platform Course 7
Optical fibre
Copper wire
Microwave link architecturesSignals to be transmitted
Introduction to Microwave Links
Asiacell Telecom Platform Course 8
MicrowaveLink
Microwave link architectures
Introduction to Microwave Links
Asiacell Telecom Platform Course 9
Diagram of a microwave link
TxRx
TxRx
0110111
0110111
1011101
1011101
F
F ’
Tx : transmitter
Rx : receiver
F : transmission frequency
Microwave link architectures
Introduction to Microwave Links
Asiacell Telecom Platform Course 10
Point-to-point radio
Point-to-multipoint radio
Microwave link architectures
Introduction to Microwave Links
Asiacell Telecom Platform Course 11
Offices
Hospitals
Universities
Nodal point
Offices
Offices
Microwave link architectures
Introduction to Microwave Links
Asiacell Telecom Platform Course 12
Central office
Heavy traffic customers
Offices
Microwave link architectures
Introduction to Microwave Links
Asiacell Telecom Platform Course 13
Microwave link architectures
Signals to be transmitted
Definition
Architectures
Radio waves
Definition
Polarization
Propagation in free space
Propagation problems
Antennas
Gain
Radiation pattern
Aperture angle
Modulation
Frequency plan
Organizations
Plan
Link budget
Transceiver hardware configurations
Course content
Introduction to Microwave Links
Asiacell Telecom Platform Course 14
λ = C * T = C / F
λ : wavelength in metres,C : speed of light in metres per second,F : frequency in Hertz,T : period in seconds.
F in GHz λ in mm2 1507 42.8613 23.0823 13.0438 7.89
Radio wavesDefinition
Introduction to Microwave Links
Asiacell Telecom Platform Course 15
Polarizations
Radio waves
VERTICAL POLARIZATION
HORIZONTAL POLARIZATION
CIRCULAR POLARIZATION
PROP
AGAT
ION
DIRE
CTIO
N
PROP
AGAT
ION
DIRE
CTIO
N
PROP
AGAT
ION
DIRE
CTIO
N
Introduction to Microwave Links
Asiacell Telecom Platform Course 16
Polarizations
E
E
Earth horizontal
Rectangular waveguide section
Radio waves
E : electric field
Introduction to Microwave Links
Asiacell Telecom Platform Course 17
Radio waves
Waveguides with different flanges
Polarizations
≅ 30 dB !
Introduction to Microwave Links
Asiacell Telecom Platform Course 18
≅
Propagation in free space
Free space = no solar effects
no effects induced by atmospheric conditions
Clearance of the first Fresnel ellipsoid
Radio waves
Introduction to Microwave Links
Asiacell Telecom Platform Course 19
First Fresnel ellipsoid
d
r
AM + MB = AB + (n*λ/2)
n = 1, first Fresnel ellipsoid
d : axis of radio wave path,
r : radius of first ellipsoid
Radio wavesPropagation in free space
Introduction to Microwave Links
Asiacell Telecom Platform Course 20
Maximum radius of first Fresnel ellipsoid
0
5
10
15
20
25
30
35
40
0 5 10 15 20 25 30 35 40
distance in km
radi
us in
m
F (GHz)2 GHz7 GHz13 GHz23 GHz38 GHz
Radius of first Fresnel ellipsoid: rmax = 0.5*√λ*d
Propagation in free spaceRadio waves
Introduction to Microwave Links
Asiacell Telecom Platform Course 21
Path Length (65.00 km)0 5 10 15 20 25 30 35 40 45 50 55 60
Elev
atio
n(m
etre
s)
0
20
40
60
80
100
120
140
160
180
200
220
240
260
Radiofrequency propagation pathFirst Fresnel ellipsoid
Radio wavesPropagation in free space
Introduction to Microwave Links
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Propagation in free space
Part of the transmitted energy that is picked up by the receive antenna
Pe
Pr
d
Sr: receive antenna
equivalent surface area
Pr = Pe * Sr / (4*π*d2) , where Sr = λ2 / (4*π)
Pr = Pe * (λ / 4 * π * d)2
α = 20 log (4 * π * d / λ)
Part of the sphereof radiated isotropic power
Radio waves
Introduction to Microwave Links
Asiacell Telecom Platform Course 23
Telegraphists’ equation:Propagation in free space
α = Pe / Pr = 20 log (4πD / λ)Free space losses
90
100
110
120
130
140
150
160
170
1 10 100 1000Distance in km
Loss
es in
dB
F (GHz)2 GHz 7 GHz 13 GHz 23 GHz 38 GHz
5020
Radio waves
Introduction to Microwave Links
Asiacell Telecom Platform Course 24
Losses in free space and absorption losses
Refraction, multiple paths
Losses due to obstruction
Losses due to rainfall
Losses in Fresnel area
Multiple paths
Radio wavesPropagation problems
Introduction to Microwave Links
Asiacell Telecom Platform Course 25
021000 21
Rddh
××
×=
COLOMBIAPROYECTO RIC chapmari.pl3
Date 09-08-99 By DO
ALCATEL
CHAPARRALLatitude 003 43 40.00 NLongitude 075 29 47.00 WAzimuth 61.13 degElevation 895 m ASLAntenna CL 0.0 m AGL
LA MARIALatitude 004 14 25.00 NLongitude 074 34 10.00 WAzimuth 241.20 degElevation 1586 m ASLAntenna CL 0.0 m AGL
Frequency = 1440.0 MHzK = 1.00
%F1 = 100.00
Path Length (117.50 km)0 10 20 30 40 50 60 70 80 90 100 110
Elev
atio
n (m
etre
s)
200300400500600700800900
100011001200130014001500160017001800
The bulging of the earth at a point on the profile is:
Radio wavesPropagation problems : correction for the roundness of the earth
Introduction to Microwave Links
Asiacell Telecom Platform Course 26
Propagation problems :Effect of atmospheric refraction
Gases in the atmosphere such as water vapour and oxygen create additional attenuation over and above that produced during propagation in free space.
13 GHz 18 GHz 23 GHz 38 GHz
0.03 dB/km 0.08 dB/km 0.19 dB/km 0.12 dB/km
Radio waves
Introduction to Microwave Links
Asiacell Telecom Platform Course 27
Propagation problems :Effect of atmospheric refraction
According to vertical variations in the atmospheric refractive index, microwave signals do not propagate in astraight line between antennas, but on a curved path whichchanges over time.
“Standard” conditions = 50% of the time, and the path curves towards the earth;
Unfavourable conditions = 0.1% of the time, and the path curves towards the sky.
Radio waves
Introduction to Microwave Links
Asiacell Telecom Platform Course 28
Propagation problems :Effect of atmospheric refraction
kmax = 4/3, R0 = 8504 km
the radiofrequency horizonis further away and theearth seems flatter.
kmin = 2/3, R0 = 4252 km
the radiofrequency horizon is closer and the earth seems rounder.
R0 kmax R0
R0 = 6378 km
kmin R0 R0
Radio waves
Introduction to Microwave Links
Asiacell Telecom Platform Course 29
60% OF RADIUS CLEARED (K=4/3)0% OF RADIUS CLEARED (K MIN) pldemo_1.pl2
Date 09-22-99 By LBT
ALCATEL
WESTONVILLELatitude 049 15 12.00 NLongitude 122 34 14.00 WAzimuth 47.41 degElevation 120 m ASLAntenna CL 36.7 m AGL
BAKER LAKELatitude 049 38 49.00 NLongitude 121 54 29.00 WAzimuth 227.91 degElevation 150 m ASLAntenna CL 53.2 m AGL
Frequency = 2000.0 MHzK = 1.33, 0.85%F1 = 100.00
Path Length (65.00 km)0 5 10 15 20 25 30 35 40 45 50 55 60
Elev
atio
n (m
etre
s)
0
20
40
60
80
100
120
140
160
180
200
220
240
Radio waves
Introduction to Microwave Links
Asiacell Telecom Platform Course 30
60% OF RADIUS CLEARED (K=4/3)0% OF RADIUS CLEARED (K MIN) pldemo_1.pl2
Date 09-22-99 By LBT
ALCATEL
WESTONVILLELatitude 049 15 12.00 NLongitude 122 34 14.00 WAzimuth 47.41 degElevation 120 m ASLAntenna CL 36.7 m AGL
BAKER LAKELatitude 049 38 49.00 NLongitude 121 54 29.00 WAzimuth 227.91 degElevation 150 m ASLAntenna CL 53.2 m AGL
Frequency = 2000.0 MHzK = 1.33, 0.85%F1 = 100.00
Path Length (65.00 km)0 5 10 15 20 25 30 35 40 45 50 55 60
Elev
atio
n (m
etre
s)
0
20
40
60
80
100
120
140
160
180
200
220
240
Radio waves
Introduction to Microwave Links
Asiacell Telecom Platform Course 31
Diffraction Algorithm PathlossMultiple Knife Edge Method Deygout
Maximum Number of Obstacles 2Obstacle Radius Method All obstacles
Foreground Loss Method Not Included
WESTONVILLE BAKER LAKE
Antenna Height (m) 36.66 53.15Distance (km) 65.00
Frequency (MHz) 2000.00K 0.85
Polarization VerticalTree Type Dry bare trees
Ground Type Average
1 Knife edgeProfile Segment (km) 0.00 65.00
Location (km) 38.47Clearance / F1 0.00
Loss (dB) 6.02
Diffraction loss (dB) 6.02Free Space Loss (dB) 134.75
Total Loss (dB) 140.77
Diffraction Algorithm PathlossMultiple Knife Edge Method Deygout
Maximum Number of Obstacles 2Obstacle Radius Method All obstacles
Foreground Loss Method Not Included
WESTONVILLE BAKER LAKE
Antenna Height (m) 36.66 53.15Distance (km) 65.00
Frequency (MHz) 2000.00K 1.33
Polarization VerticalTree Type Dry bare trees
Ground Type Average
1 Knife edgeProfile Segment (km) 0.00 65.00
Location (km) 38.47Clearance / F1 0.70
Loss (dB) 0.00
Diffraction loss (dB) 0.00Free Space Loss (dB) 134.75
Total Loss (dB) 134.75
Radio waves
Introduction to Microwave Links
Asiacell Telecom Platform Course 32
Propagation problems:
Attenuation due to hydrometeors
Attenuation, in dB per kilometre6 GHz 10 GHz 20 GHz 40 GHz
Fine rain 0.013 0.07Downpour 0.012 0.08 0.45 1.5Storm 0.22 1.2 5.5 13Heavy storm 1.2 5.5 18 27
Radio waves
Introduction to Microwave Links
Asiacell Telecom Platform Course 33
Propagation problems:
Attenuation due to hydrometeors
Radio waves
Per cent of Tim
e Gradient
Introduction to Microwave Links
Asiacell Telecom Platform Course 34
Radio wavesPropagation problems:
Attenuation due to hydrometeors
Per cent of Tim
e Gradient
Introduction to Microwave Links
Asiacell Telecom Platform Course 35
Microwave link architectures
Signals to be transmitted
Definition
Architectures
Radio waves
Definition
Polarization
Propagation in free space
Propagation problems
Antennas
Gain
Radiation pattern
Aperture angle
Modulation
Frequency plan
Organizations
Plan
Link budget
Transceiver hardware configurations
Course content
Introduction to Microwave Links
Asiacell Telecom Platform Course 36
Antennas
Introduction to Microwave Links
Asiacell Telecom Platform Course 37
Antennas
Introduction to Microwave Links
Asiacell Telecom Platform Course 38
HornG SdB = 10 4
2logη πλ
S: projected surface areaη: antenna gain, from 50% to 70%
Frequency 2 GHz 4 GHz 8 GHz 13 GHz 23 GHz 38 GHzEfficiency 50% 50% 60% 60% 70% 70%Diameter 3.7 m 32 dB 38 dB 45 dBDiameter 2.4 m 28 dB 34 dB 42 dB 46 dBDiameter 1.2 m 28 dB 36 dB 40 dB 46 dBDiameter 0.6 m 34 dB 40 dB 44 dBDiameter 0.3 m 34 dB 38 dB
GainAntennas
Introduction to Microwave Links
Asiacell Telecom Platform Course 39
Radiation patternsAntennas
Introduction to Microwave Links
Asiacell Telecom Platform Course 40
Aperture angle at 3 dB
θλ
− ≈370
dB d.
Frequency 2 GHz 4 GHz 8 GHz 13 GHz 23 GHz 38 GHzDiameter 3.7 m 2.8° 1.4° 0.7°Diameter 2.4 m 4.4° 2.2° 1.1° 0.7°Diameter 1.2 m 2.2° 1.3° 0.8°Diameter 0.6 m 2.7° 1.5° 0.9°Diameter 0.3 m 3° 1.8°
Antennas
Introduction to Microwave Links
Asiacell Telecom Platform Course 41
Microwave link architectures
Signals to be transmitted
Definition
Architectures
Radio waves
Definition
Polarization
Propagation in free space
Propagation problems
Antennas
Gain
Radiation pattern
Aperture angle
Modulation
Frequency plan
Organizations
Plan
Link budget
Transceiver hardware configurations
Course content
Introduction to Microwave Links
Asiacell Telecom Platform Course 42
Modulation
Ρ Ρ
Ρ Ρ
Ρ Ρ
Ρ Ρ
Ρ Ρ
Ρ Ρ
Ρ Ρ
Ρ Ρ
Ρ Ρ
Ρ Ρ
Ρ Ρ
Introduction to Microwave Links
Asiacell Telecom Platform Course 43
BPSK
Modulation
S ( t )
O.L.
Frequency F0
A ( t ) xMixer
Modulator
-1
0
1
0 1 2 3 4 5
-1
0
1
0 1 2 3 4 5
-1
0
1
0 1 2 3 4 5
Introduction to Microwave Links
Asiacell Telecom Platform Course 44
X
X
OL
++π/2
Q sin ω0t
P cos ω0t
cos ω0t
P
H
A(t)
Q
F0
S(t)sin ω0t
4QAM Modulator
H/2
H/2
-1
-0,5
0
0,5
1
0 1 2 3 4 5 6 7 8 9 10
-1
-0,5
0
0,5
1
0 1 2 3 4 5 6 7 8 9 10
4QAM
-1,5
-1
-0,5
0
0,5
1
1,5
0 1 2 3 4 5 6 7 8 9 10
Modulation
-1
-0,5
0
0,5
1
0 1 2 3 4 5 6 7 8 9 10
-1
0
1
0 1 2 3 4 5
Introduction to Microwave Links
Asiacell Telecom Platform Course 45
The basic duration of a symbol cannot be indefinitely reduced, but the number of bits per symbol can be increased:
2n signal states = n bits transmitted for a symbol.
The Nyquist criterion defines the Nyquist band: minimumbandwidth of a transmission channel.
Modulation Nyquist band Theoretical peak power BER
BPSK B P 10-n
4QAM B/2 P 10-n
16QAM B/4 P+6.5 dB 10-n
Modulation
Introduction to Microwave Links
Asiacell Telecom Platform Course 46
Microwave link architectures
Signals to be transmitted
Definition
Architectures
Radio waves
Definition
Polarization
Propagation in free space
Propagation problems
Antennas
Gain
Radiation pattern
Aperture angle
Modulation
Frequency plan
Organizations
Plan
Link budget
Transceiver hardware configurations
Course content
Introduction to Microwave Links
Asiacell Telecom Platform Course 47
Frequency plan
ITU: International Telecommunications Union
CEPT: European Conference on Posts andTelecommunications
FCC: Federal Communication Commission (≈ CEPT)
Organizations
Introduction to Microwave Links
Asiacell Telecom Platform Course 48
Duplex separation = ⏐Fn - F ’⏐
F4
F3
F2
F1 Fn
F'4
F'3
F'2
F'1 F'nVerticalpolarization
Horizontalpolarization
CEPT T/R 13-02 Duplex separation = 1008 MHz
Fn (MHz) = F0 (MHz) + 798 + 28n
F ’n (MHz) = F0 (MHz) + 1806 + 28n
where F0 = 21,196 MHz and n =1,…,20
Frequency plan
Introduction to Microwave Links
Asiacell Telecom Platform Course 49
Frequency plan
1, 3, 5 V
1 ’, 3 ’, 5 ’ V 2, 4 V
2 ’, 4 ’ V
1, 3, 5 H1 ’, 3 ’, 5 ’ H
Introduction to Microwave Links
Asiacell Telecom Platform Course 50
Microwave link architectures
Signals to be transmitted
Definition
Architectures
Radio waves
Definition
Polarization
Propagation in free space
Propagation problems
Antennas
Gain
Radiation pattern
Aperture angle
Modulation
Frequency plan
Organizations
Plan
Link budget
Transceiver hardware configurations
Course content
Introduction to Microwave Links
Asiacell Telecom Platform Course 51
Diffraction Algorithm PathlossMultiple Knife Edge Method Deygout
Maximum Number of Obstacles 2Obstacle Radius Method All obstacles
Foreground Loss Method Not Included
BONNY LNG AMENAM
Antenna Height (m) 69.39 68.60Distance (km) 51.16
Frequency (MHz) 2000.00K 1.33
Polarization HorizontalTree Type Dry bare trees
Ground Type Average
1 Isolated obstacleProfile Segment (km) 0.00 51.16
Location (km) 25.94Radius (km) 8337.06
Clearance / F1 0.87Loss (dB) 0.00
Diffraction loss (dB) 0.00Free Space Loss (dB) 132.67
Total Loss (dB) 132.67
Diffraction Algorithm PathlossMultiple Knife Edge Method Deygout
Maximum Number of Obstacles 2Obstacle Radius Method All obstacles
Foreground Loss Method Not Included
BONNY LNG AMENAM
Antenna Height (m) 69.39 68.60Distance (km) 51.16
Frequency (MHz) 2000.00K 0.81
Polarization HorizontalTree Type Dry bare trees
Ground Type Average
1 Isolated obstacleProfile Segment (km) 0.00 51.16
Location (km) 25.94Radius (km) 11719.56
Clearance / F1 0.30Loss (dB) 5.70
Diffraction loss (dB) 5.70Free Space Loss (dB) 132.67
Total Loss (dB) 138.37
Introduction to Microwave Links
Asiacell Telecom Platform Course 52
Microwave link architectures
Signals to be transmitted
Definition
Architectures
Radio waves
Definition
Polarization
Propagation in free space
Propagation problems
Antennas
Gain
Radiation pattern
Aperture angle
Modulation
Frequency plan
Organizations
Plan
Link budget
Transceiver hardware configurations
Course content
Introduction to Microwave Links
Asiacell Telecom Platform Course 53
Simplified link budgetFrequency = 23 GHzDistance = 10 kmBit rate = 2 tributariesAntenna diameter = 0.6 m
Transmittedpower
dBm
Transmitantenna gain
Received power
Free spacelosses
Threshold 10-6
≅ -87dBm
Threshold 10-3
≅ -90dBm
Threshold 10-8
≅ -85dBm
Qualitythreshold
Receive antennagain
Marginrelative toDCP : 40 dB
PTx = 12 dBm
PN = - 50 dBm
DCA
DC
DCP
Propagationalarm
DCA PRx
- 75 dBm
- 80 dBm
Connectionlosses
ConnectionlossesTx Rxα
Free space losses = - 140 dB
Tx connection losses = - 1 dBTx antenna gain = 40 dB
Rx antenna gain = 40 dBRx connection losses = - 1 dBTotal losses = -62 dB
Introduction to Microwave Links
Asiacell Telecom Platform Course 54
1+0 Configuration
TxRx
TxRx
01101110
01101110
1011101
1011101
F
F ’
Hardware configurations
Introduction to Microwave Links
Asiacell Telecom Platform Course 55
1+1 HSB Configuration
1011101
F ’Rx 1
1011101
FTx 101101110
Tx x
Rx xoo
Rx 1
F Tx 1 01101110
Tx x
Rx xoo
Hardware configurations
Introduction to Microwave Links
Asiacell Telecom Platform Course 56
Frequency Diversity Configuration
TxRx
TxRx
F2
F2’
TxRx
TxRx
F1
F1’1100101 101010
011010
1101101
Hardware configurations
Introduction to Microwave Links
Asiacell Telecom Platform Course 57
Space Diversity Configuration
TxRx
01101110
TxRx
01101110
1011101
1011101
F
F ’
TxRx
F
Hardware configurations
Introduction to Microwave Links
Asiacell Telecom Platform Course 58
Microwavelink!
By [email protected] Engineer Specialist