MW Frequency planning

1. Microwave Network
Planning and Design--
Frequency Planning

2. Microwave Frequency Planning
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Purpose of frequency planning:
Make reasonable use of the frequency resources
so that the new microwave links and existing ones
do not interfere with each other and the system
availability of the microwave network can be
ensured. In the process of planning for the
microwave network, appropriate frequency bands
and channels should be selected and interference
avoidance should also be taken into account.

3. Microwave Frequency Planning
Division of microwave frequency bands:
LF MF HF VHF UHF SHF EHF
Infrared
rays
Microwave frequency bands suggested by ITU-R for common use:
Frequency
Band
4 GHz L6 GHz U6 GHz 7 GHz 8 GHz 11 GHz 13 GHz 15 GHz 18 GHz 23 GHz 26 GHz 38 GHz
Range 3.6-4.2 5.9-6.4 6.4-7.1 7.1-7.7 7.7-8.5 10.7-11.7 12.7-13.2 14.5-15.3 17.7-19.7 21.1-23.6 24.5-26.5 37.0-39.5
Page 3
Microwave
10 Km 1 Km 100 m 10 m 1 m 10 cm 1 cm 1 mm
f 30 KHz 300 KHz 3 MHz 30 MHz 300 MHz 3 GHz 30 GHz 300 GHz
Visible
light

4. Microwave Frequency Planning
Principles of selecting proper frequency bands:
1. Select proper frequency bands according to the frequency resources (licenses) owned by
the carriers and the stipulations of local radio management committees.
2. Select proper frequency bands according to the characteristics of the designed networks
and routes. For example, high-frequency bands are generally used for mobile networks and
MANs because quite a few channels available at high-frequency bands.
3. Select proper frequency bands according to their characteristics.
● Low-frequency bands (L6G/U6G/7G/8G/11G) are suitable for long-distance links and
high-frequency bands (13G/15G/18G/23G/26G/38G) are suitable for short-distance
links.
● Due to the limited number of channels existing at low-frequency bands, interference
tends to arise in the long-distance transmission.
● High-frequency bands are suitable for high-speed data transmission and interference
sustainable because there are many channels with broad bandwidth.
● High-frequency antennas feature high gains. Compared with low-frequency bands,
high-frequency bands require small clearance. Towers with Page these 4
antennas properly
used can be lower than others.

5. Microwave Frequency Planning
Illustration of the selection of microwave frequency bands:
LAN/PCS
1 2 3 4 5 8 10 20 30 40 50
Page 5
1.5 2.5
Long-distance
backbone networks
Area, local, and edge networks
28
34
Mbit/s
34
140
155
Mbit/s
28
34
140
155
Mbit/s
3.3 11 GHz
GHz

6. Microwave Frequency Planning
Division of microwave frequency bands:
Frequency Shift Frequencies (MHz) (T-R Spacing) Use
4-7 GHz 161, 154, 245 Long-distance network
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backbones
8 GHz 126, 161, 154. 199, 266, 311 Long-distance network
backbones
11-13 GHz 266 Short and medium distance
15 GHz 308, 420, 490, 315. 720, 728 Short and medium distance
18 GHz 340, 1092.5, 1008, 1010, 1560 Short and medium distance
23 GHz 600, 1050, 1232, 1008, 1200, Short distance in urban areas
26 GHz 855, 1008 Short distance in urban areas
28 GHz 1008 Short distance in urban areas
32 GHz 812 Short distance in urban areas
38 GHz 700, 1260 Short distance in urban areas

7. Microwave Frequency Planning
Figure 1 for configuring microwave radio frequency channels:
Lower half band Upper half band
1 2 n 1' n'
Page 7
Channel number
Frequency
F3
F1
Fo
F2
Center frequency
Fo: center frequency
2'

8. Microwave Frequency Planning
Figure 2 for configuring microwave radio frequency channels:
Each channel consists of a pair of transmission and receiving frequencies.
Page 8
Tx
Rx
Tx
Rx
Channel Channel
1
1'
n
n'
1
1'
n
n'
High site Low site
The site which the receiving frequency higher than
transmitting frequency is called a high site.
The site which the receiving frequency is lower than
the transmitting frequency is called a low site.

9. Microwave Frequency Planning
Principles of selecting proper bandwidth of microwave channels:
The bandwidth of a microwave channel is decided by the signal rate and radio
modulation scheme.
The most commonly used ways are the quadrature phase shift keying (QPSK) and
quadrature amplitude modulation (QAM).
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● 2 x E1 requires 3.5 MHz (QPSK)
● 4 x E1 requires 7 MHZ (QPSK)
● 8 x E1 requires 14 MHz (QPSK)
● 16 x E1 requires 28 MHz (QPSK)
● STM-1 requires 28 MHz (128QAM)
The more advanced modulation is, the smaller the bandwidth is required.
The 16E1 signal subject to QPSK requires the same bandwidth (28 MHz) as the STM-1
signal subject to 128 QAM does.

10. Microwave Frequency Planning
Principles of selecting proper microwave
c1.h Tarny nnoetl tso: select the special frequency resources (licensed) used by other carriers even if
these frequency bands are not used in some areas (in case they may be used in the future).
2. If the planned microwave link features the same routing or parallel routing as another
microwave link, it is recommended that the frequency band/channels different from those of the
existing link are used. A different polarization mode should be configured even if the same
channel is adopted as a result of the little interference and big margin proved by the calculation
and analysis.
3. If the angle between two interleaving routes is comparatively small (for example, smaller
than 30 degrees), a different channel should be selected. If the angle is quite large (for
example, larger than 60 degrees), the same channel can be used provided a different
polarization mode is configured. The same channel with the same polarization mode can be
used only when the angle is larger than 90 degrees. This is a generally adopted principle for
microwave frequency planning. For different equipment, antenna configuration, or capacity,
analysis should be made on the link accordingly.
4. In the design, the microwave link should be as far from the scatter communication station
and the satellite communications earth station as possible. When the antenna of the microwave
station is directed to the satellite orbit with a tolerance of ±2 degrees, the frequency band of the
communication satellite cannot be used.
Page 10

11. Microwave Frequency Planning
Example for the microwave frequency planning:
Front-back
interference
In frequency planning, reusing of frequency resources should be taken
into account, the internal and external interference should be avoided,
and the link quality should be enhanced.
Polarization should alternate every other hop for the decrease of
overreach interference. The polarization configured alternate every hop
is conducive to the decrease of front-back interference upon the
antenna.
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1H 1H
1V
1V
2H
Overreach 1H
interference

12. Microwave Frequency Planning
Two-frequency system and quadruple-frequency system used
in microwave frequency planning:
For the 1+1 system or 2+0 system of the frequency diversity, the use of the two-frequency
system can save the frequency resources, while the use of the quadruple-frequency
system can decrease the internal and external interference and enhance the
link quality. Whether to select the two-frequency system or the quadruple-frequency
system depends on the interference within the planned microwave network system and
the mutual interference between the microwave links to be established and the links
existing in the system.
Case 1: When the link to be
established interleaves with an
existing one, the two-frequency
system can be used for the
former provided the same
system is used for the existing
link, and a different channel
should be selected in this case.
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Existing
link
Link to be established
1,
3
1,
3
2,
4
2,
4

13. Microwave Frequency Planning
Two-frequency system and quadruple-frequency system used in
microwave frequency planning:
Page 13
Case 2: When the link to be
established interleaves with an
existing one, the quadruple-frequency
system can be used
for the former provided the
same system is used for the
existing link. In this case, the
neighboring links should have
different channels.
Existing
link
Link to be established
1,
3
2,
4
2,
4
1,
3
Case 3: When the link to be
established has a branch,
the quadruple-frequency
system should also be
used for this branch.
1,
3
2,
4
1,
3

14. Microwave Frequency Planning
Two-frequency system and quadruple-frequency system
used in microwave frequency planning:
Page 14
Case 4: When the link to be established
forms a loop-line with quite small angles,
the quadruple-frequency system should
be selected.
1,
3
2,
4
2,
4
Case 5: When the routing deflection angles
are too great, but the angles of La and Lb
are quite small, for example, smaller than 15
degrees, comparatively great overreach
interference may occur if the two-frequency
system is selected for Site A and Site D.
Therefore, the quadruple-frequency system
should also be used in this case.
1,
3
1,
3
1,
3
A
B
C
D
2,
4
La
Lb
Case 6: The quadruple-frequency system should also be selected in such circumstances as the
front-back ratio difference of the antenna is smaller than 60dB, the SWR(Standing Wave Ratio) of
the antenna feeder is large, and the equipment has weak immunity to interference.

15. Microwave Frequency Planning
Selection of proper frequency diversity channels:
When the microwave link is designed to adopt the frequency diversity protection,
attention should be paid to the selection of channel spacing between the master
channel and diversity channel. The formula to calculate the improvement in the
frequency diversity is as follows:
Page 15
where
: frequency diversity improvement
: frequency spacing between the master channel and diversity channel
: Radio center frequency
: flat fade margin
: transmission section length
From the formula, we can find that the improvement in the frequency diversity is proportional to the
channel spacing. Generally, the channel spacing should be at least 2 times of the radio frequency
bandwidth. For a greater improvement in the diversity, the channel spacing should be as large as
possible.

16. Case Study for Microwave Frequency Planning
GSM Network frequency planning in Mauritius:
Case study purpose: to be familiar with the preceding rules for microwave frequency
planning and apply them to practice.
Project area: Mauritius in the Eastern Hemisphere and Southern Hemisphere
Requirement of the longitude
and latitude of the site:
Frequency resource: assigned by the user, 7G/28M: 2 chs; 8G/7M: 4 chs
Page 16
Contents of planning:
● Channel
● pHliagnhn ainngd low sites configuration
● Configuration of the polarization mode for the channel

17. Case Study for Microwave Frequency Planning
Complete the routing and capacity planning by referring to the
right map:
Page 17
Legend:
STM-1
8E1
4E1
New relay stations
Service hub
BTS

18. Case Study for Microwave Frequency Planning
Proper channels of different bandwidths should be selected according to the capacity of
the microwave link and frequency resource the user owns.
Frequency resource owned by the user:
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Channel selection 1:
Channel No. Frequency Channel No. Frequency
1
h
761
0
1l 744
2
3
h
766
6
3l 749
8
7G: 7.4-7.7; number of channels: 2; channel spacing: 28 MHz

19. Case Study for Microwave Frequency Planning
Proper channels of different bandwidths should be selected according to the capacity
of the microwave link and frequency resource the user owns.
Frequency resource owned by the user:
Page 19
Channel selection 2:
8G: 7.9-8.4; number of channels: 2; channel spacing: 14 MHz
Channel No. Frequency Channel No. Frequency
1
h
817
8
1l 791
2 819
2
h
2
2l 792
6

20. Case Study for Microwave Frequency Planning
Proper channels of different bandwidths should be selected according to the capacity
of the microwave link and frequency resource the user owns.
Frequency resource owned by the user:
Page 20
Channel selection 3:
8G: 7.9-8.4; number of channels: 4; channel spacing: 7 MHz
Channel No. Frequency Channel No. Frequency
1
h
817
8
1l 791
2 818
2
h
5
2l 791
3 819
9
h
2
3l 792
4 819
6
h
9
4l 793
3

21. Case Study for Microwave Frequency Planning
Proper channels of different bandwidths should be selected according to the capacity
of the microwave link and frequency resource the user owns.
The following channels are selected according to the capacity of the link:
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Channel selection 4:
For STM-1, select f1 and f3 channels (7425-7725) with 28 MHz bandwidth.
For 8E1 PDH, select f1 and f2 channels (7900-8400) with 14 MHz bandwidth.
For 4E1 PDH, select f1, f2, f3, and f4 channels (7900-8400) with 7MHz bandwidth.

22. Case Study for Microwave Frequency Planning
Implement the frequency planning in Pathloss by using the preceding rules flexibly.
Points to be noted in frequency planning:
Page 22
Frequency planning in Pathloss:
1. All microwave sites must clearly mark the CALL SIGN, which cannot be the
same and will be used in the later interference calculation.
2. Two-frequency system. To prevent the co-channel interference, a site should
use different channels for multi-directions.
3. Deploy the sites in such a way as high sites and low ones alternate. Check the
interference calculation report to see whether this principle is observed.
4. Configure the sites with two polarization modes as required.

23. Case Study for Microwave Frequency Planning
Page 23
Frequency planning in Pathloss:
Example for frequency planning in Pathloss:
1. Access the PL4.0 program.
2. Log in to the network module.
3. Open the completed routing file.
4. Take the link between Site 5 and Site 21 for instance. Set the CH parameters
after setting the parameters for Radio and Antennas.
5. Click CH. The TX Channels dialog box is displayed, as shown in the next page.

24. Case Study for Microwave Frequency Planning
Page 24
Frequency planning in Pathloss:
Click CH. The TX
Channels dialog box
is displayed, as
shown in the figure
on the right side :

25. Case Study for Microwave Frequency Planning
Page 25
Frequency planning in Pathloss:
Click Lookup. In
the File dialog box
that is displayed,
click Open and
select the
corresponding
frequency planning
file from Freqplan,
as shown in the
figure on the right
side.

26. Case Study for Microwave Frequency Planning
Page 26
Frequency planning in Pathloss:
Open the target
frequency planning
file, as shown in
the figure on the
right side :

27. Case Study for Microwave Frequency Planning
Page 27
Frequency planning in Pathloss:
SDH adopts the hot
backup system. Select
f1 channel with 7 GHz
bandwidth as required,
and then select the
proper frequency for
use, site 1 as the high
site, and the vertical
polarization mode
before returning to the
previous page and
finally click OK, as
shown in the figure on
the right side :

28. Case Study for Microwave Frequency Planning
Page 28
Frequency planning in Pathloss:
According to the
two-frequency
system, the
frequency planning
for the SDH
backbone ring is
completed, as
shown in the figure
on the right side:

29. Case Study for Microwave Frequency Planning
Page 29
Frequency planning in Pathloss:
According to the two-frequency
system, the frequency planning
for the SDH backbone ring is
completed, as shown in the
figure on the right side.
Note that a site (Site 5) in the
ring has both high and low
stations due to the odd number
of the BTSs. In frequency
planning processes, this
should be avoided.
3l 7498 H 7666
3h
3l 7498 V 7666 3h
1h 7610 V 7442
1l
3h 7666 H 7498
3l
1l 7442 V 7610
1h
Site
35/1
1h 7610 H 7442 1l
3h 7666 V 7498
3l
Site
5/2
Site
21/1
Site
25/1
Site
44/1
ADD1
ADD2

30. Case Study for Microwave Frequency Planning
Page 30
Frequency planning in Pathloss:
Statistics about the
frequency planning
for the SDH
backbone ring:
Site Name 1 Site Name 2
Frequency/Polarization
Mode
Site 5 (high) Site 21 (low) 1/V
Site 21 (low) Site 35 (high) 3/V
Site 35 (high) Site 44 (low) 1/H
Site 44 (low) Site 25 (high) 3/H
Site 25 (high) ADD 2 (low) 1/V
ADD 2 (low) ADD 1 (high) 3/V
ADD 1 (high) Site 5 (low) 3/H

31. Case Study for Microwave Frequency Planning
Page 31
Frequency planning in Pathloss:
Take Site 21 for
instance. In Pathloss,
implement the
frequency planning for
the link of 8E1. Select
the 1+1 hot backup
mode, f1 channel in 8
GHz bandwidth, and
vertical polarization,
as shown in the figure
on the right side:

32. Case Study for Microwave Frequency Planning
Page 32
Frequency planning in Pathloss:
Take Site 21 for
instance. The result
of the frequency
planning for the link
of 8E1 is shown in
the figure on the
right side:
8E1
frequency
configuration

33. Case Study for Microwave Frequency Planning
Page 33
Frequency planning in Pathloss:
Take Site 21 for
instance. The result
of the frequency
planning for the link
of 4E1 is shown in
the figure on the
right side:

34. Case Study for Microwave Frequency Planning
Page 34
Frequency planning in Pathloss:
The 2-hop SDH link, 1-hop 8E1 link,
and 3-hop 4E1 link converge at Site
21. As 4E1 has quite a few links, try
to select different channels in the
direction of 8E1 links to reduce the
interference. In this case, f1, f3, and
f4 channels with 8 GHz bandwidth
are selected and a different
polarization mode is adopted. The
statistics about the frequency
planning for Site 21 are listed in the
table on the right side:
Site
Names 1
Site
Names 2
Equipment Planned
Frequency
T R
Site 21
(low)
Site 8
(high)
4E1 4H 7933 8199
Site 21
(low)
Site 38
(high)
4E1 3V 7926 8192
Site 21
(low)
Site 39
(high)
4E1 1H 7912 8178

35. Case Study for Microwave Frequency Planning
1h 8178 H 7912
1l
Page 35
Frequency planning in Pathloss:
The result of the
frequency
planning for Site
21 is shown in
the figure on the
right side:
Site 5
Site 21
Site 35
3h 8192 V 7926 3l
1h 7610 V 7442 1l 3l 7498 V 7666 3h
4h 8199 H 7933
4l
1h 8178 V 7912
1l 8E1-4PSK
Site 8
Site 38
Site 39

36. Page 36
Case Study for Microwave
Frequency Planning
Frequency planning in Pathloss:
The reference result of
the frequency planning
is shown in figure on
the right side.
Note:
H---F1 V---L
H/L indicates the high/low
site.
F1 indicates the SDH
frequency; f1 indicates the
PDH frequency; V
indicates the polarization
mode.

37. Case Study for Microwave Frequency Planning
Complete all frequency planning for the microwave network according to
the relevant principles and output the design result. The frequency
configuration in the software will be used for the future interference
analysis.
Page 37
Frequency planning in Pathloss: