Presentation on Microwave System Overview

1. Microwave System Overview
Presented By
Snr. Er. Sujan Shrestha
1

2. Agenda
– Basics of Microwave communication
– Various components used in microwave
communication
– various architecture of microwave radio
equipment
– Microwave link design considerations
– Basic recommendation in microwave links
2

3. Terrestrial Microwave
Communication
3

4. Radio Relay Communication
4

5. 5

6. Microwave Transmission Network
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7. 7

8. Microwave Link
• A radio link that uses electromagnetic wave in the
frequency range of 3GHz – 300 GHz as a carrier of
information that travel through atmosphere
• Radio Relay Communication system
• Terrestrial microwave communication
• Line of sight communication
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9. RF Channel Arrangement in U6GHz
Band
RF CHANNEL RF FREQUENCY(MHz)
(LOW)
RF CHANNEL RF FREQUENCY(MHz)
(HIGH)
1L 6460 1H 6800
2L 6500 2H 6840
3L 6540 3H 6880
4L 6580 4H 6920
5L 6620 5H 6960
6L 6660 6H 7000
7L 6700 7H 7040
8L 6740 8H 7080
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10. RF Channel Arrangement
in 8GHz band
RF CHANNEL RF FREQUENCY(MHz)
(LOW)
RF CHANNEL RF FREQUENCY(MHz)
(HIGH)
1L
8293
1H
8412
2L
8307
2H
8426
3L
8321
3H
8440
4L
8335
4H
8454
5L
8349
5H
8468
6L
8363
6H
8482
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• 6 RF channels with 14 MHz Channel Spacing

11. RF Channel Arrangements
in 15 GHz band
• 60 RF Channels with 7 MHz Channel Spacing
• 15 Ghz channel assignment.xlsx
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12. Components used in Microwave
communication
1. Antenna
– Parabolic dish antenna
2. Radio unit
i. All indoor type,
ii. Split-Mount type,
iii. Full-Outdoor Type
3. Transmission medium
i. IF coaxial feeder cable,
ii. waveguide
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13. Antenna
13

14. Antenna Radio Pattern
14

15. • Some important parameters of antenna
– Gain, dBi
– 3dB Beamwidth, degree
– Cross Polarization Discrimination, dB
– Front-Back Ratio
– Electrical compliance
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16. 16

17. • Dimensions of Antenna used
– U6GHz+L6GHz
• 0.9, 1.2,1.8,2.4m
– 8GHz
0.6,0.9,1.2
– 15 GHz
• 0.3,0.6,1.2,1.8
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18. Radio unit
• Functions as modulator, demodulator,
transmitter, receiver, power amplifier
• 3 types of radio architecture
– All indoor type radio
– Split Mount type radio
– Full Outdoor radio
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19. 19

20. – All Indoor type radio
• All radio units is indoor
• High power consumption
• Traditional radio, now almost obsolete
• Occupies more space
• More heated, requires Air Conditioning System
• Harris ( Fujitsu) in NT
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21. Split Mount Radio Architecture
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22. – Split type radio
• Radio unit is split into two units: ODU,IDU
• ODU, outdoor unit,IDU, indoor unit
• ODU is the RF transmitter/receiver
• IDU contains the modulator, demodulator, multiplexer,
control and traffic interface elements
• Less power consumption, Less heated
• Occupies less space
• Harris SDH, Siae SPDH, SIAE Hybrid, Ceragon PDH, NEC,
RTN 905/910, in NT
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23. Transmission Media
• Medium used to connect the radio unit with
the antenna
• Waveguide, connects the all indoor radio with
antenna
• IF cable or Co-axial cable, connects the ODU
with IDU
• ODU may be directly mounted to Antenna, or
connected to the antenna with flexible
waveguide, called flex twist
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24. 24

25. Full Outdoor Radio
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26. 26

27. Full Outdoor Radio
• All Outdoor Radio
• Zero Foot Print solution
• No need of 19”rack
• Less power consumption
• Siae ALFOPlus, Ceragon IP-50C,RTN 310/320, in NT
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28. 28

29. Microwave link design
considerations
• Duplexing,
• Polarization
• Received level
• Receiver threshold value
• Fade margin
• Receiver sensitivity/Threshold
• Line of sight, Fresnel zone
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30. Duplexing
• Frequency Division Duplexing
• Transmitter and receiver operate at different carrier
frequencies.
• Tx low: transmitter frequencies is lower than receiver
frequency
• Tx high: transmitter frequencies is higher than receiver
frequency.
• In a repeater station, if one station is Tx low, other station
must be Tx high.
• Avoid Tx Low/High violation
• Duplex spacing
– U6 GHz : 340 MHz
– 8 GHz: 119 MHz
– 15 GHz: 420 MHz
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31. 31
Radio path link budget
Transmitter 1
Receiver 1
Splitter Splitter
Transmitter 2
Receiver 2
Output
Power (Tx)
Branching
Losses
waveguide
Propagation
Losses
Antenna
Gain
Branching
Losses
Received
Power (Rx)
Receiver threshold Value
Fade Margin

32. • Receiver Threshold: The received level below
which the system generates error, or the
performance degrades.
• Fade Margin: The difference between the
received level and the receiver threshold
value.
• The higher the fade margin is the more
reliable the link is.
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33. Line of sight
Radius of fresnel zone
•Increses with increse of
distance
•Decreses with increase of
frequency
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34. Strategies for Higher Capacity in
Microwave Technology
1. Higher Channel Bandwidth 7,14,28,40,56,80,112
MHz
– Higher channel bandwidth (upto 2000MHz) available in E-
Band (70/80 GHz).
– Dual Carrier Multicore Radio units (SIAE ALFOPlus2,
Ceragon IP-50C)
2. Higher Order Modulation with ACM,
4,16,64,128,256,512,1024,2048,4096 QAM
3. Co channel Dual Polarization, CCDP
4. Header Suppression, Compression
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35. CCDP XPIC Radio Link
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36. 36

37. Transmitter/Receiver Specification
Capacity Bandwidth
( MHz)
Modulation TX
Power
Rx Threshold
at 10 -6 BER
1*STM-1 55 16 QAM 26.5 -76.5
1*STM-1 40 64 QAM 25.5 -74.0
1*STM-1 27.5 128 QAM 24.5 -71.0
2*STM-1 55 128 QAM 24.5 -66.0
2*STM-1 50 256 QAM 22.5 -66.0
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38. Higher Order Modulation
38

39. Adaptive Modulation
Modulation RX Threshold
64 QAM -73
128 QAM -70
256 QAM -67
512 QAM -64
1024 QAM -61
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40. Header Suppression/Compression
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41. Basic recommendations
• Confirm line of sight for radio link
– Use software tools ( pathloss, atoll, google earth),
perform mirror test, visual inspection ( binocular) site
survey
• Use higher frequency bands for shorter hops
and lower frequency bands for longer hops
• Avoid Tx Low/High violation
• Prefer less channel bandwidth and higher
modulation to meet capacity requirement
• Prefer ACM in higher modulation
• Radio link installation as per link budget
provided.
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