GSM Coverage Planning
When you have completed this course you should be able
to:
·Grasp coverage planning process
·Grasp link budget process and factors that impact it
·Grasp ZTE link budgets of various series equipment
·Grasp meanings of common propagation models
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Contents
1 Overall Thought of Coverage Planning & Step Description .................................................................. 1
1.1 Aims .................................................................................................................................................. 1
1.2 Steps .................................................................................................................................................. 1
1.2.1 Confirm the Size and Scope of the Area to Be Covered ........................................................ 1
1.2.2 Confirming Coverage Level Requirement and Coverage Probability .................................... 2
1.2.3 Link Budget of Uplink/Downlink Power Balance ................................................................. 8
1.2.4 Propagation Model Selection and Parameter Correction ....................................................... 8
1.2.5 Cell Radius Estimation ........................................................................................................... 9
1.2.6 Size Estimation (Coverage) .................................................................................................. 10
1.2.7 Site Layout ........................................................................................................................... 12
1.2.8 Coverage Simulation ............................................................................................................ 13
1.3 Prompt for Key Points ..................................................................................................................... 13
2 Descriptions of Various Parameters in Link Budget ............................................................................. 15
2.1 Mainstream Equipment ................................................................................................................... 15
2.1.1 Mainstream Equipment ........................................................................................................ 15
2.1.2 Carrier Frequency/Set-top Output Power ............................................................................. 16
2.1.3 Combiner .............................................................................................................................. 19
2.1.4 Networking Combiner Modes and Corresponding Losses of Various Main Equipment ..... 28
2.1.5 Coverage Enhancement Technique ...................................................................................... 39
2.2 MS Transmission Power ................................................................................................................. 41
2.3 Sensitivity ....................................................................................................................................... 42
2.3.1 BTS Receiver Sensitivity ..................................................................................................... 42
2.3.2 MS Receiver Sensitivity ....................................................................................................... 45
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2.3.3 Gain of TMA to BTS Receiver Sensitivity ........................................................................... 45
2.4 Feeder, Jumper and Connector ........................................................................................................ 48
2.4.1 Without Tower Amplifier ...................................................................................................... 48
2.5 Antenna ............................................................................................................................................ 50
2.5.1 BTS Antenna Gain ................................................................................................................ 50
2.5.2 BTS Antenna Height ............................................................................................................. 50
2.5.3 MS Antenna Gain ................................................................................................................. 51
2.5.4 MS Antenna Height .............................................................................................................. 52
2.5.5 Diversity Gain ....................................................................................................................... 52
2.6 Margins ............................................................................................................................................ 52
2.6.1 Rayleigh Fading (Fast Fading) Margin ................................................................................. 52
2.6.2 Shadow Fading (Slow Fading) Margin (Log-normal Fading Margin).................................. 53
2.6.3 Interference Margin .............................................................................................................. 59
2.6.4 Body Loss ............................................................................................................................. 59
2.6.5 Building Penetration Loss ..................................................................................................... 59
2.6.6 Car Penetration Loss ............................................................................................................. 60
2.7 Recommended Minimum Required Level and Design Level .......................................................... 60
2.7.1 900M ..................................................................................................................................... 60
3 Link Budget ............................................................................................................................................... 63
3.1 Link Budget Process ........................................................................................................................ 63
3.1.1 Downlink Budget .................................................................................................................. 63
3.1.2 Uplink Budget ....................................................................................................................... 63
3.1.3 Equivalent Maximum Allowed Path Loss ............................................................................ 64
3.2 Link Budget Tool V3.3 (Promoted for Use) .................................................................................... 64
3.3 Link Budget Tool V3.2.X (Not Promoted from Now on) ................................................................ 64
3.3.1 Tool Structure........................................................................................................................ 65
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3.3.2 Precautions ........................................................................................................................... 69
4 Common Propagation Model & Its Parameter Values ......................................................................... 71
4.1 Okumura-Hata Model ..................................................................................................................... 71
4.1.1 Applicable Scope .................................................................................................................. 71
4.1.2 Propagation Loss Formula ................................................................................................... 71
4.1.3 Various Correction Factors ................................................................................................... 72
4.2 Cost231model ................................................................................................................................. 76
4.2.1 Applicable Scope .................................................................................................................. 76
4.2.2 Propagation Loss Formula ................................................................................................... 76
4.2.3 Various Correction Factors ................................................................................................... 77
4.3 Common Expression of Okumura-Hata and COST231 Model ....................................................... 77
4.3.1 Applicable Scope .................................................................................................................. 77
4.3.2 Propagation Loss Formula ................................................................................................... 77
4.3.3 Common Correction Factors ................................................................................................ 77
4.4 Standard Universal Model (AIRCOM Expression Formula) .......................................................... 78
4.4.1 Applicable Scope .................................................................................................................. 78
4.4.2 Propagation Loss Formula ................................................................................................... 78
4.4.3 Propagation Model Parameter Value .................................................................................... 79
5 Precautions for Coverage Simulation ..................................................................................................... 85
5.1 Consider Coverage Probability ....................................................................................................... 85
5.2 Do Not Consider Coverage Probability .......................................................................................... 86
6 Recommendations on Project Operation ............................................................................................... 87
6.1 Adopt V3.2.1 Method for New Project ........................................................................................... 87
6.2 Adopt V3.1.2 Method for Old Continuous Project ......................................................................... 87
6.3 Maximum Difference between Two Versions ................................................................................. 87
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1 Overall Thought of Coverage Planning & Step Description
1.1 Aims
Under the precondition that the required coverage level and coverage probability are
satisfied and via uplink/downlink power balance link budget and cell radius estimation,
the coverage planning aims to estimate the site size that satisfies the coverage
requirement, lay out sites the via information such as ground object information in the
electronic map, building highlight in Google Earth and layout sites of existing sites,
and to coverage simulation authenticate site layout result via coverage simulation
where conditions permit, thereby ensuring coverage planning rationality.
1.2 Steps
On the whole coverage planning includes the following several steps:
Confirm the size and scope of the area to be covered
Confirm coverage level requirement and coverage probability
Uplink/downlink power balance link budget
Calibration and selection of propagation model parameter
Cell radius estimation
Size estimation (in the aspect of coverage)
Site layout
Coverage simulation
Below is introduction to every link.
1.2.1 Confirm the Size and Scope of the Area to Be Covered
Confirming the size and scope of the area to be covered is the precondition for
coverage planning, so it is necessary to do our best to do a good job in documentation
in the material collecting period.
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The coverage area is mainly demonstrated by Polygon. Classifying and conducting
area statistics on different wireless environment coverage areas by defining the
boundary and attribute (DU/MU/SU/RU) of polygon are the basic input conditions for
size estimation.
There are several methods for getting Polygon in various wireless environments:
To be provided by customer. Relatively mature carrier usually provides in his tender
documents the Polygon necessary to be covered according to the local conditions
before releasing his tender documents, such as Hunch. In this case, it is necessary to
conduct subsequent coverage planning according the Polygon defined by the customer.
Collect information before bidding. For annual key project, it is necessary to push the
market department and the local representative office put in human power and
resources in advance, collect and reserve Polygon and population distribution
information to form Polygon base so that network planning can be conducted in the
possible earliest time when the project is kicked off. Collection means includes buying
the latest local electronic map (planet format) and combining it with GE, instructing
local employees to draw Polygon or buying population distribution situation and zone
area of various zones or organizations such as local design institutes, third party
consultation companies or collecting information about network sizes of other local
carrier. Kick off outsourcing in advance, which shall determine coverage areas of
various grades via survey and consulting electronic map.
1.2.2 Confirming Coverage Level Requirement and Coverage Probability
Confirming the level and coverage probability required by the customer is the primary
condition for link budget and radius estimation. This can be handled in two cases:
1. If the customer definitely puts forward the required level and coverage
probability n the tender documents or makes definite answers to them in his
clarifications, we take the level required by the customer as the acceptance
level and calculate design level according to it.
2. If the customer does not put forward them in the tender documents, or does not
clarify them, or that it is directive bidding, it is necessary for us to provide level
value and coverage probability recommendation. At this time, the acceptance
level should keep consistent with the calculated minimum required level,
thereby calculating design level.
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The following are definitions of acceptance level, design level and minimum required
levels.
1.2.2.1 Minimum Required Level
The minimum level needs to satisfy MS receiving sensitivity, and usually in the
network design it is also necessary to reserve certain margin to offset (compensate)
Rayleigh Fading, interference and body loss in wireless environment. If indoor and
in-car coverage is required, it is also necessary to consider building penetration loss
(BPL) and car penetration loss (CPL), so as to ensure the conversation experience of
indoor or in-car subscriber. The receiving end needs to reach the minimum level
requirement, that is, the minimum level requirement necessary for maintaining normal
conversation in a real case (outdoor/indoor/in-car). The minimum required level is
impacted by wireless environment and is mainly related to the average building
penetration loss of indoor subscribers in different environments.
Usually it is possible to calculate it with the following formula:
SSmin_req (outdoor) = MSsen + RFmarg + IFmarg + BL MS outdoor
Where,
SSmin_req Signal Strength of Minimum Require Minimum required level
MSsen MS sensitivity MS receiving sensitivity
RFmarg Rayleigh Fading Margin Fast fading margin
IFmarg Interference Margin interference margin
BL Body Loss Body loss
CPL Car Penetration Loss Car penetration loss
BPL Building Penetration Loss Building penetration loss
1.2.2.2 Design Level
Besides the various above-mentioned margins, it is also necessary to add additional
margins on SSmin_req to process the impact of slow fading on coverage probability. In
planning, it is necessary to consider these factors and consider coverage level and
coverage probability. We call the level value at this time design level, SS design.
The formula to calculate design level is:
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SS design (outdoor) = SSmin_req(outdoor) +LNFmarg MS outdoor
Where,
LNFmarg Log-normal Fading Margin Slow fading margin
1.2.2.3 Acceptance Level
When cell planning is completed, it is necessary to use network measure means to
conduct reasonable verification. The aim is to measure the receiving level and estimate
whether this level value can satisfy the expected coverage KPI index. This index is
closely related to wireless environment, the expectations of different wireless
environment for target coverage KPI should be different. We call such coverage KPI
expectation acceptance level. Generally speaking, the customer defines in acceptance
level in the tender documents (but it is not necessary to put forward definite phrase
“acceptance”). Common expressions are as follows:
DU: 70dBm@95%
MU: 75dBm@95%
SU: -80dBm@95%
RU: 85dBm@95%
Highway: -87dBm@90%
Note: The expression before @ is acceptance level, and the expression after @ is the
required coverage probability (generally it is area coverage probability).
When the customer has defined acceptance level, it is possible to get the design level
by directly adding the shadow fading margin on the acceptance level. When the
customer has not clarified the acceptance level, we may believe that acceptance level
SS acceptance is equal to the minimum required level SSmin_req in various
corresponding environments.
The formula is:
SSacceptance=SSby_operator
Where,
SSby_operator is the acceptance level required the operator.
Or, the formula is:
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SS acceptance (outdoor) = SSmin_req (outdoor) MS outdoor
SS acceptance (in-car) = SSmin_req (in-car) MS in-car
SS acceptance (indoor) = SSmin_req (indoor) MS indoor
In the DT process of the coverage acceptance procedure, it is recommended to adopt
car top antenna to avoid introducing extra body loss and car loss. Of course, it is also
necessary to consider loss compensation when car top antenna is introduced, such as
the loss of feeder that connects the antenna and the mobile phone, and the gain of car
top antenna. In acceptance, if we do not adopt car top antenna, it is necessary to
consider car loss and body loss.
It is necessary to note that , here the expressions such as “MS outdoor”, “in-car”, and
“indoor” only refer to the names of the target level values determined by behaviors of
different subscribers in different wireless environments, which are descriptive
vocabulary, and they do not stand for measurement sites. For example, “indoor is
-70dBm” does not mean that requiring to measure the level in indoor area and get the
level of -70dBm, instead it should be understood that, to satisfy the conversation need
of indoor subscriber, outdoor (at street level) measure level needs to reach -70dBm
(considering mainly the indoor building penetration loss). Here the expression Indoor
has no further meaning, and can be replaced by many other words, such as ”good
coverage”, “perfect”, “class 1”, and “1”. In the same analysis, the meanings of the
words such as “deep indoor”, “in-car” are so too.
1.2.2.4 Calculation of Several Levels
Case 1: When the customer has not definitely put forward acceptance level.
Outdoor
No. Parameter
SSmin_req
Minimum
required level
SSdesign
Design level
SSacceptance
Acceptance level
A Receiver sensitivity Y Y Y
B Fast fading margin Y Y Y
C Body loss Y Y Y
D Interference margin Y Y Y
E Building penetration
loss N N N
F Car loss N N N
G Slow fading margin N Y N
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H Calculation result H=A+B+C+D H=A+B+C+D+G H=A+B+C+D
Indoor
No. Parameter
SSmin_req
Minimum
required level
SSdesign
Design level
SSacceptance
Acceptance level
A Receiver sensitivity Y Y Y
B Fast fading margin Y Y Y
C Body loss Y Y Y
D Interference margin Y Y Y
E Building penetration
Loss Y Y Y
F car loss N N N
G Slow fading margin N Y N
H Calculation result H=A+B+C+D+E H=A+B+C+D+E+G H=A+B+C+D+E
In-car
No. Parameter
SSmin_req
Minimum
required level
SSdesign
Design level
SSacceptance
Acceptance level
A Receiver sensitivity Y Y Y
B Fast fading margin Y Y Y
C Body loss Y Y Y
D Interference margin Y Y Y
E Building penetration
loss N N N
F Car loss Y Y Y
G Slow fading margin N Y N
H Calculation result H=A+B+C+D+F H=A+B+C+D+F+G H=A+B+C+D+F
Case 2: When the customer has definite put forward the acceptance level.
Outdoor
No. Parameter
SSmin_req
Minimum
required level
SSdesign
Design level
SSacceptance
Acceptance level
A Receiver
sensitivity Y Y Y
B Fast fading margin Y Y Y
C Body loss Y Y Y
D Interference
margin Y Y Y
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E Building
penetration loss N N N
F Car loss N N N
G Slow fading
margin N Y N
H Calculation result H=A+B+C+D H= value defined by
customer + G
Value defined by
customer
Note: When the customer has put forward acceptance level value, we get design level by directly
adopting the value defined by the customer + slow fading margin. At this time it no long
demonstrates minimum required level.
Indoor
No. Parameter
SSmin_req
Minimum
required level
SSdesign
Design level
SSacceptance
Acceptance level
A Receiver
sensitivity Y Y Y
B Fast fading margin Y Y Y
C Body loss Y Y Y
D Interference
margin Y Y Y
E Building
penetration loss Y Y Y
F Car loss N N N
G Slow fading
margin N Y N
H Calculation result H=A+B+C+D+E H= Value defined by
customer + G
Value defined by
customer
Note: When the customer has put forward acceptance level value, we get design level by directly
adopting the value defined by the customer + slow fading margin. At this time it no long
demonstrates minimum required level.
In-car
No. Parameter
SSmin_req
Minimum
required level
SSdesign
Design level
SSacceptance
Acceptance level
A Receiver
sensitivity Y Y Y
B Fast fading margin Y Y Y
C Body loss Y Y Y
D Interference
margin Y Y Y
E Building N N N
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penetration loss
F Car loss Y Y Y
G Slow fading
margin N Y N
H Calculation result H=A+B+C+D+F H= Value defined by
customer + G
Value defined by
customer
Note: When the customer has put forward acceptance level value, we get design level by directly
adopting the value defined by the customer + slow fading margin. At this time it no long
demonstrates minimum required level.
1.2.3 Link Budget of Uplink/Downlink Power Balance
Link budget of uplink/downlink power balance refers to estimating the system
uplink/downlink coverage capability by reviewing various factors in the path for
system uplink/downlink signal propagation, and getting the maximum path loss
allowed by the link under the precondition that a certain quality is ensured.
We respectively assess the maximum path losses allowed by uplinks/downlinks, and
adopt the lower one as the final maximum path loss, and take this as the path loss in
estimating coverage radius.
Various parameters relating to link budget are described in detail in the following
chapter.
Currently link budget tool mainly includes two: LinkBudget.exe tool and excel tool.
LinkBudget.exe tool needs license support.
1.2.4 Propagation Model Selection and Parameter Correction
Currently the common propagation model is the standard macro cell model, which
belongs to empirical model, and mainly adopts the universal model applied in
AIRCOM and CNP. It originates from Okumura-Hata model and COST231 model, and
adds more environment parameters on this basis, enabling the model to describe the
real environment more precisely.
For micro cell the best way is to adopt the ray track model, and currently in the industry,
the relatively universal one is Volcano model. However, ray track model has a very
high requirement for the precision of the electronic map (it is required that the
precision is at least 5 m and streets and buildings are clearly described), and its
calculation speed is extremely slow, so it is rarely used in large-sized projects.
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The propagation features of each country, each region, each landform and each relief
are different. For each country and each region, it is recommended to correct out the
propagation model suitable for this area via CW test (continuous wave test). Otherwise,
it may result in the case that the deviation between the estimated radius and the real
one is too big. It is generally believed that, for a relatively reasonable model to be
compared with the real test data of CW, the Mean Error is 0, and Standard Deviation <
= 8dB.
Seen from the status quo, to correct a set of propagation model for each country and
each region, it is necessary to input huge resources such human resource and material
resource. And various projects are different in their respective urgencies, so they have
different requirements for the precision of the propagation model. Currently there are
two main measures: One is that, for large or key project, it is recommended to push the
market department and local representative offices to input resources and start
outsourcing in advance before the project is kicked off and correct the propagation
model for the local area in detail, and complete documentation in network planning
department and network optimization department. The second is, for general project or
when the project is urgent in time, and there is no reserve in the local area, it is
advisable to select, from the documented propagation model base, the model whose
environment is the same or similar, and apply it into the project.
It is worthwhile to note that the corrected propagation model only reflects the change
of the median level of the local signal propagation, and combines Clutter offset and
Clutter Through km/dB to characterize the contribution of each ground object to the
median of signal level and the impact of each ground object on the median of signal
level, and it cannot reflect coverage probability. If it is necessary to reflect coverage
probability, it is also necessary to consider shadow fading margin. In CNP, relative to
AIRCOM, it is possible to reflect coverage probability via adding Coverage Probability
graphic layer and Coverage Subcell graphic layer.
1.2.5 Cell Radius Estimation
In the preceding two steps, one gets the maximum path loss allowed by
uplink/downlink; the other succeeds in correcting the reasonable model that can reflect
the local wireless signal propagation. The following step is to inversely deduce the cell
coverage radius.
This process is relatively simple, and the formula is as follows.
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Lb=k1+k2lgd+k3Hm+k4lgHm+k5lgHb+k6lgHbLgd+k7*diffraction + clutter Loss
We know Lb, various K value parameters in model, Hm (MS height), Hb (BTS antenna
height), it is only necessary to inversely deduce d (the distance between BTS and Ms,
km). At this time, d is the estimated radius (R) and is unit is km.
It is necessary to note that:
1. In link budget tool, it is impossible to combine with electronic map, so it is
impossible to consider the impact of various ground objects on median level
(Clutter Loss) in real case, nor to consider the impact of diffraction caused by
topographic relief. So in conducting link budget and estimating the radius, we
generally only consider the impact of 6 parameters, namely, k1~ k6, and do not
list k7 and Clutter in the table. But it does not mean that k7 and Clutter are
unimportant; on the contrary, these two parameters, k7 in particular, have a
huge impact on coverage, especially in foothill area and mountain area where is
relatively big topographic relief.
2. In submitting propagation model parameters to the customer, or conducting
simulation in the real case, it is necessary to set k7. If propagation model is
corrected, it is also necessary to set the corresponding Clutter offset and Clutter
Through km/dB.
3. There may be deviation between the radius in simulation and the one calculated
in link budget, mainly the deviation is relatively big in mountain area, and
generally in plain area the deviation should be within 100m~200m.
4. If uplink in link budget is limited, there is also a certain deviation between
coverage simulation result and link budget result. It is mainly due to the fact
that simulation only calculates downlink path loss without considering uplink
path loss. The case will appear that the radius in simulation is bigger than the
estimated result of cell radius in link budget.
5. For the configurations, meanings and impacts of k7 and Clutter, see
“Simulation FAQ”.
1.2.6 Size Estimation (Coverage)
When the coverage radius of the typical level in every kind of environment
(DU/MU/SU/RU/Road) is obtained, it is necessary to calculate the area covered by a
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single site. The formula is:
● Omni site
S single site = 2.6 x R^2
● Directional site
S single site = 1.95 x R^2
When we get S single site, we use divide the area of each Polygon by the area
of the corresponding single site, and we get the number of the sites within this
Polygon.
By adding up the numbers of the sites within all Polygons, it is possible to get
the site size of the whole network.
For directional site, the cell radius is R (the side length of regular hexagon is 1/2R).
The area of each regular hexagon is 3 x sqr t (3) R*R/8, and the area of three regular
hexagons in one three-sector base station is 9 x sqrt (3) R*R/8, which is approximately
equal to 1.94856*R*R. Reserve two digits after the decimal point, and the coverage
area of one three-sector base station is 1.95*R*R.
In the network with ideal cell topology, the distance between two three-sector
directional sites is 1.5R.
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For omni site, the cell radius is R (the side length of the regular hexagon is R).
The area of each regular hexagon is 6 x sqrt (3)*R*R/4, which is approximate equal to
2.598076*R*R. Cancel the two digits after the decimal point, and the coverage area of
one omni cell is 2.6*R*R.
In the network with ideal cell topology, the distance between two omni sites is about
1.73R.
1.2.7 Site Layout
When the network size is obtained, in the next step it is necessary to lay these sites out
into each Polygon. There are two methods:
1. Automatic site layout and manual adjustment
When Polygon is drawn, it is advisable to use automatic site layout tool to
complete automatic site layout. The principle of automatic site layout is based
on the coverage radius of the set cell, and to draw grid within Polygon. The
sites laid out with the automatic site layout tool are evenly distributed in
various Polygons.
Currently the self-developed tool APSTool (Automatic Plotting Site Tool) can
support automatic site layout and use license to control the use authority. Later
we integrate this tool into planning simulation soft CNP.
Currently the automatic site layout tool supports:
For vacant network, it is advisable to lay sites according to ideal cell.
Import the sites of the existing network and combine the sites of the automatic
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site layout result and the existing network sites by defining certain combination
rules, and use the existing resources of existing networks.
Analyze abnormal sites, list all sites that break the rules and are within too short
distance, and implement automatic association of maps to facilitate engineers to
adjust some sites.
Of course, one of the input conditions of automatic site layout tool is Polygon. Without
this input, automatic site layout cannot be implemented.
Manual site layout
Manually lay out sites in plan area, and workload increases obviously. For project short
of Polygon, it is only possible to lay out sites manually.
1.2.8 Coverage Simulation
Import site layout result into AIRCOM or CNP simulation software and conduct field
intensity coverage simulation. Because the simulation software considers the factors in
the electronic map such as topographic relief, the simulated coverage map and the
coverage radius of the single site may be somewhat inconsistent with the radius
estimated in link budget. Reasonably adjust some sites whose coverage is obstructed by
landform or whose coverage is too big due to landform so as to meet coverage index.
One of the conditions for simulation is that it is necessary to have electronic map in
3-dimensional Planet format without which simulation cannot be done.
1.3 Prompt for Key Points
1. If the required receiving level is directly appointed by the carrier, in link budget
it is only necessary to consider shadow fading margin, and all other margins
can be ignored. At this time, the receiving level defined by the customer is
thought to be sufficient to ensure reliable reception for end subscribers, and in
planning, it is only necessary to consider shadow fading margin to ensure
coverage probability.
2. If the required receiving level is not appointed, instead it is calculated
according to receiving sensitivity (our recommended value), in link budget, it is
necessary to consider all margins on the basis of the sensitivity in order to
ensure reliable reception.
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3. In coverage simulation, if we use AIRCOM and need to reflect coverage
probability, we need to consider slow fading margin on EiRP (or PA value). For
example, when the size of the pre-sales bidding project is estimated and its sites
are also laid out, it is necessary t o consider the coverage of the corresponding
coverage probability. If CNP simulation is used, it is unnecessary to consider
the slow fading margin on PA, it is possible to bet coverage subcell graphic by
setting std dev of various clutters, target coverage probability and target edge
coverage level (acceptance level). The graphic layers displayed by various
colors in the graph are the coverage ok graphs of the corresponding subcell
layers.
4. In coverage simulation, if it is unnecessary to reflect coverage probability, it is
no longer necessary to consider any margin on the basis of EiRP (or PA value).
For example no margin needs to be considered in CW test propagation
correction, and the comparison between the path test of the existing network
and simulation result (when it does not reflect coverage probability)
5. Propagation model correction is very necessary, propagation model
documentation and base establishment are equally important, and it is necessary
to push many departments to jointly concern with it. Automatic tool for
propagation model selection is developed in CNP road map so that it is possible
to select from the propagation model base the propagation model similar to the
current environment.
6. Drawing Polygon is the precondition for automatic site layout tool.
7. In simulation, it is necessary to consider k7. The algorithm for the effective
height of BTS antenna is recommended to set to be Relative or Slop.
Particularly, in the environment where there are mountains and hills with
relatively large ups and downs of landforms, it is necessary to adopt Relative or
Slop algorithm. Propagation mode correction tool in CNP can correct the K
value of regular models and it can also provide the effective height of BTS
antenna and the diffraction algorithm that most comply with this environment.
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2 Descriptions of Various Parameters in Link Budget
Uplink/downlink power balance link budget plays a key role in estimating size as well
as one of the technical points with which customers are concerned most. To facilitate
you to operate and understand it and to unify the output, we have successively
developed two sets of link budget tools: Excel-based link budget tool programmed with
VBA macro, and exe tool (recommended to use) developed on the basis of the former.
Chapter 2 describes in detail the meanings of various parameters in link budget, and
precautions in the setup.
2.1 Mainstream Equipment
2.1.1 Mainstream Equipment
Link budget tool contains the mainstream equipment of ZTE in three periods, namely,
V2 series, 8000 series and SDR series. S8001in 8000 series is Pico base station,
generally to satisfy indoor coverage, the current link budget tool does not contain (it is
mainly due to the fact that macro cell model is not applicable to indoor signal
propagation prediction).
V2 equipment is no longer promoted in bidding, use 8000 series and SDR series base
stations as much as possible when there is no special requirement or when equipment is
not appointed.
Product Series BTS TYPE
SDR series
RU02
RU60
R8860
8000 series
B8018
B8112
M8202
M8206
V2 series
BTS V2
OB06
BS30
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BS21
It is necessary to note that:
1. The difference of carrier frequency output powers of different mainstream
equipment and carrier frequency configuration factors cause different set-top
output powers for each type of equipment under each type of combiner mode,
having a relatively big impact on link budget. Before conducting link budget, it
is necessary to firstly confirm with the International Market Department the
equipment promoted in various scenarios for this bidding, and get the latest
parameters of the equipment and unify the standard in order to avoid the
inconsistency between the link budget parameter and the equipment actually
used.
2. For the link budget of bidding project, calculate according to the equipment
actually selected and the nominal index.
3. For the link budget of the existing network, when the set-top output power is
actually measured, fill in set-top output power according to the real conditions.
If no actual measurement is conducted, then calculate according to nominal
index.
4. For the nominal index parameters of the specific equipment, refer to PD or the
quick-finding manual for product index. Download PD and quick-finding
manual for the latest product index in the equipment materials of GSM product
material server, and it is also advisable to pay attention to materials released via
mails.
2.1.2 Carrier Frequency/Set-top Output Power
The following is a list showing the carrier frequencies/set-top output powers of various
main equipment types, pay attention to the descriptions in the remark.
Equipment
Type
TX POWER
Remark GMSK(Voice,
CS1~CS4,MCS1~MCS4) 8-PSK(MCS5~MCS9)
RU02 45w (set-top power) 28w (set-top power)
Set-top power is related to carrier frequency
configuration. It is applicable when the
number of carrier frequencies in each cell is
smaller than 4. When it is bigger than 2 carrier
frequencies, it needs to pass a combiner, and
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its loss is 3dB. It supports
DPCT/DDT/FWDR/IRC technology. It is dual
density carrier.
RU60 60w (set-top power) 40w (set-top power)
Set-top power is related to the number of logic
carrier frequencies configured on each RRU. It
supports DDT/FWDR/IRC technology, but
does not support DPCT. It is multi-density
carrier.
R8860 60w (set-top power) 40w(set-top power)
Set-top power is related to the number of logic
carrier frequencies configured on each RRU. It
supports DDT/FWDR/IRC technology, but
does not support DPCT. It is multi-density
carrier.
B8018 60w (carrier frequency
output power)
40w (carrier frequency
output power)
Set-top power is related to cell carrier
frequency configuration, combiner selection
and whether to add antenna. It supports
DPCT/DDT/FWDR/IRC technology. It is dual
density carrier.
B8112 60w (carrier frequency
output power)
40w( carrier frequency
output power)
Set-top power is related to cell carrier
frequency configuration, combiner selection
and whether to add antenna. It supports
DPCT/DDT/FWDR/IRC technology. It is dual
density carrier.
M8202 30w (set-top power) 19w(set-top power)
M8202 has no Combiner (without built-in or
external one), set-top output is always 30w
(GMSK)/19w (8PSK), and does not support
DPCT, and it only supports DDT/FWDR/IRC.
t is dual density carrier.
M8206 30w (set-top power) 18w (set-top power)
M8206 has external combiner ECU and
considers ECU loss when it is necessary to
combine paths. In DPCT, ECU is introduced to
synthesize power in ECU, and then return it to
the CMB within the carrier frequency for
phase detection. At this time, ECU loss is no
longer calculated. M8206 supports
DPCT/DDT/FWDR/IRC. It is dual density
carrier.
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BTSV2
850M/1800M/1900M:
60W (EDGE carrier
frequency)
40w (non-EDGE carrier
frequency)
900M/EGSM:
60W (EDGE carrier
frequency)
40w (non-EDGE carrier
frequency)
80w (non-EDGE carrier
frequency)
All are carrier frequency
output power
40w (EDGE carrier
frequency)
All are carrier frequency
output power
Set-top output power is related to cell carrier
frequency configuration, combiner selection
and whether to add antenna. It does not
support coverage enhancement technique.
EDGE carrier frequency power is 60w. There
are still two other carrier frequencies that do
not support EDGE, and their output powers are
respectively 40w and 80w. Where, only
GSM900M has the power of 80w, and other 3
frequency bands, namely, 850M, 1800M, and
1900M do not have.
OB06
850M/1800M/1900M:
60W (EDGE carrier
frequency)
40w (non-EDGE carrier
frequency)
900M/EGSM:
60W(EDGE carrier
frequency)
40w (non-EDGE carrier
frequency)
80w (non-EDGE carrier
frequency)
All are carrier frequency
output power
40w (EDGE carrier
frequency)
All are carrier frequency
output power
Set-top power is relate to cell carrier frequency
configuration, combiner combination and
whether to add antenna. It does not support
coverage enhancement technique. EDGE
carrier frequency power is 60w. There are still
two other carrier frequencies that do not
support EDGE, and their output powers are
respectively 40w and 80w. Where, only
GSM900M has the power of 80w, and other 3
frequency bands, namely, 850M, 1800M, and
1900M do not have.
BS30
900M/EGSM:
2W (used as indoor
coverage )
40W
1800M:
2W (used as indoor
coverage )
20W
All are carrier frequency
output power
900M/EGSM:
2W (used as indoor
coverage )
40W
1800M:
2W (used as indoor
coverage )
20W
All are carrier frequency
output power
There is 1 carrier frequency for each cabinet of
BS30. In indoor coverage, the carrier
frequency output power is 2w. In outdoor
coverage, carrier frequency output power is
40w (900), 20w (1800).
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BS21
850M/1800M/1900M:
60W (EDGE carrier
frequency)
40w (non-EDGE carrier
frequency)
900M/EGSM:
60W(EDGE carrier
frequency)
40w (non-EDGE carrier
frequency)
80w (non-EDGE carrier
frequency)
All are carrier frequency
output power
40w (EDGE carrier
frequency)
All are carrier frequency
output power
Set-top power is relate to cell carrier frequency
configuration, combiner combination and
whether to add antenna. It does not support
coverage enhancement technique. EDGE
carrier frequency power is 60w. There are still
two other carrier frequencies that do not
support EDGE, and their output powers are
respectively 40w and 80w. Where, only
GSM900M has the power of 80w, and other 3
frequency bands, namely, 850M, 1800M, and
1900M do not have.
2.1.3 Combiner
2.1.3.1 Combiner Loss List
Loss of combiner unit used on SDR series equipment:
In adopting RU02 (or RU02 + RU02A) to configure the cell to be S4, it is necessary to
pass Combiner within TPAU unit (recorded as COM here), and the combiner loss is
3dB (those of 900M and 1800M are all 3dB).
Loss of combiner used in V3 series equipment:
Combiner (900M) Loss (dB)
CDUG 4.4
CEUG 3.5
CENG 5.3
CENG/2 5.3
ECDUG 1
ECU 3.5
Combiner (1800M) Loss (dB)
CDUD 4.6
CEUD 3.6
CEND 5.5
CEND/2 5.5
ECDUD 1
ECU 3.5
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Loss of combiner used in V2 series equipment:
Combiner (900M) Loss (dB)
CDUG 4.4
CEUG 3.5
ECDUG 1
Combiner (1800M) Loss (dB)
CDUD 4.6
CEUD 3.6
ECDUD 1
2.1.3.2 NCDU
(a) is front panel diagram, and (b) is internal structure connection diagram
NCDU port description:
TX1-2: TX port connecting DTRU
ETX: Output port connecting built-in/external combiner
RX1-4: RX port connecting DTRU
ERX1-2: Connect NCEU and NCEN to expand the quantity of carrier frequencies of
single cell.
According to different operation frequency bands, NCDU is divided into NCDUG
(900M frequency band) and NCDUD (1800M frequency band). NCDU module has
built-in combiner and directly provides external antenna interface.
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2.1.3.3 NCEU
(a) is front panel diagram, and (b) is internal connection diagram
NCEU port description:
OTX1-2: ETX port connecting NCDU
ERX1-2:ERX port connecting NCDU
TX1-4: TX port connecting DTRU
RX1-4: RX port connecting DTRU
According to different operation frequency bands, NCEU can be divided into NCEUG
(900M frequency band) and NCEUD (1800M frequency band). NCEU mainly
functions to expand TX and RX port quantity. ERX1/2 and OTX1/2 respectively
connect to the splitter that splits one path into two and the combiner that combines two
paths into one. When it is used together with CDU unit, it is possible to conveniently
expand the capacity of B8018, B8112 base station from S444 to S888.
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2.1.3.4 NCEN
(a) is front panel diagram, and (b) is internal connection diagram.
NCEN port description:
OTX1-2: ETX port connecting NCDU
ERX1-2: ERX port connecting NCDU
TX1-6: TX port connecting DTRU
RX1-8: RX port connecting DTRU
According to different operation frequency bands, NCEN can be divided into CENG
(900M frequency band) and CEND (1800M frequency band). The main advantage of
NCEU module lies in its ability to implement quick capacity expansion. All carrier
frequency modules are connected to NCDU via NCEN. ERX1/2 port and OTX1/2 port
butt the corresponding RX/TX ports of NCDU. Via combined application, it is possible
to implement the case in which 12 carrier frequencies in one cell use only one pair of
antenna and feeder.
When quantity of carrier frequencies is 5~6 carrier frequencies, it is advisable to use
NCEN/2 + CDU Bypass to reduce combiner loss and to balance the power at the same
time. The difference between NCEN/2 and NCEN is that NCEN contains two splitters,
each of which splits one route into four routes while NCEN/2 contains two splitters,
each of which splits one route into two routes. The diagram for the internal connection
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of NCEN/2 is shown in the figure below.
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2.1.3.5 NECDU
(a) is front panel diagram, and (b) is internal connection diagram.
NECDU port description:
ITX: TXcom port connecting DTRU
RX1-2:RX port connecting DTRU
RXD1-2: RX div port connecting DTRU
According to different operation frequency bands, NECDU is divided into NECDUG
(900 frequency band) and NECDUD (1800 frequency band). NECDU module is the
special combiner/splitter module when the base station adopts DPCT and 4 way
diversity reception technology. In the module, there are only one set of duplexer and
two way receiving splitter units. It is possible to conveniently to enable 2 carrier
frequencies to implement 4 way diversity receptions. For heavily configured site, in
order to implement DPCT and 4 way diversity reception technology, it is necessary to
use NCDU to replace NECDU in order to provide more diversity reception ports.
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2.1.3.6 NMCDU
(a) is front panel diagram, and (b) is internal connection diagram.
NMCDU port description
ITX: TXcom port connecting DTRU or output port connecting built-in combiner
RX1-2: RX port connecting DTRU
RXD1-2: RX div port connecting DTRU
According to different operation frequency bands, NMCDU is divided into NMCDUG
(900M frequency band) and NMCDUD (1800M frequency band). The module has a
built-in duplexer and 2 way receptions, it is possible to use one NMCDU module to
implement diversity reception. This combiner is designed specially to meet the
demands of co-frame networking of dual frequency network. By using NMCDU, single
rack of B8018 base station can configure a maximum of S222 (frequency band 1) +
S444 (frequency band2); and single rack of B8112 base station can configure a
maximum of S222 (frequency band 1) + S222 (frequency band 2). If the carrier needs
further expansion, it is necessary to adopt NCDU to replace NMCDU. Additionally,
NMCDU can also be used to deploy and implement DPCT and FWDR enhancement
coverage technology.
2.1.3.7 ECU
ECU is combiner extension module, which is passive module. It is mainly used to
conduct extension configuration and provide external combiner function, and is used in
the cases such as DPCT and indoor coverage. ECU is external combiner unit and is
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used according to real configuration and installed at the bottom of RTU. The figure
below shows its internal structure:
ECU includes ECDU and ECGU, which can be used in the following two
configurations.
● ECGU: 824 MHz~960 MHz frequency range
● ECDU: 1710 MHz~1990 MHz frequency range
The figure below shows the ECU external structure.
ECU External Interface Description
Interface ID Description
COM0 Connect to antenna or load port
COM1
ANT0 Connect to RTU
ANT1
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MON Connect to RTU
LOAD Connect to COM0 or COM1
● Through combination, the signals of the two ports of ANT0 and ANT1 are
output from COM0 and COM1. According to site type configuration
requirement, COM0 and COM1 can select to connect antenna or load port.
● MON port can conduct coupling on the output power of COM0 port and send it
to RTU for detection.
● LOAD provide absorption load.
2.1.3.8 EFU
EFU is external filter unit. It consists of two filters with the same index, installed on
the back of base station RTU. It receives via the antenna two ways diversity signals
with the same frequency band, at the same time, it interferes with signals beyond the
signal frequency band and suppresses spurious radiation. Use it according to real
configuration. The external filter is applied in S1/1 site or in the case in which it is
necessary to increase diversity antennae.
The figure below shows the exterior structure of the filter.
EFU External Interface Description
Interface ID Interface Model Description
ANT0 N model connector Connect to antenna
ANT1
RX0 TNC model connector Connect to RTU
RX1
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2.1.4 Networking Combiner Modes and Corresponding Losses of Various Main Equipment
2.1.4.1 B8200 + RU60
S1/1/1-S6/6/6 (do not use DDT and FWDR)
For single sector with 6TRX sites or less, RF configuration and connection are
completely different, it is necessary to configure 3 pieces of RU60 modules for both,.
For base band, according to the TRX quantity, it is necessary to configure one UBPG it
is below S4/4/4, and to configure two pieces of UBPGs when it exceeds 12 TRX. The
figure below shows the connection of RU60 antenna and feeder. In the configuration,
the total set-top output power of each cell is 60W, and the power is equally shared by
various TRXs.
For example, there are 1 RRU and 3 carriers for each cell, the set-top output power of
each carrier is 60/3 = 20w.
S7/7/7-S12/12/12 (do not use DDT and 4-way transmission diversity)
When the sinle sector exceeds 6 carrier frequencies, it is necessary to configure two
RU60 modules for each cell. In terms of base band, the quantity of base band boards is
still determined according to carrier frequency quantity. When each cell has two pieces
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of RU60, it is still necessary to have a duplex bipolarization antenna, and the two
pieces of RU60 are bridged via extension RX interface. The set-top output power of
each RU60 maintains 60W, which is equally shared by various TRXs. The specific
antenna connection is as follows:
S1/1/1-S6/6/6 (use DDT + FWDR)
When transmitting and receiving diversity technology is adopted, each cell must be
configured with two pieces of RU60, at the same time, it is also necessary to have two
duplex bipolarization antennae. The same signal transmitted by two pieces of RU60 is
logically thought to be in the carrier frequency. At this time, the quantity of base band
boards needs to be calculated according to the quantity of physical carrier frequencies.
For example S4/4/4 under DDT+FWDR mode should calculate and configure base
bands according to 24TRX. The connection of antenna and feeder under this mode is
shown in the figure below:
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Additonally, the configuration principle of dual frequency networking is the same as
that of the single one. The difference is that each RU60 module can only support one
frequency band, so the dual requency cell needs at least two RU modules. For example,
for GSM900S222 + GSM1800S222, it is necessary to configure one RU60-900 and
one RU60-1800 for each cell. If it is necessary to share the antenna and the feeder, it is
also necessary to configure external bandwidty combiner.
2.1.4.2 B8200 + RU02 (RU02A)
1. Configure via RU02
● Single RU02 supports S2 configuration (does not use DDT or FWDR), and the
set-top output is 45w (GMSK).
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● RU02 supports 4 diversity reception S2 configuration and the set-top output is
45w (GMSK).
TX 1TX 2PA1 PA2
TPAUTDUP
RPDC
LNA_
RX11
LNA_
RX12
LNA_
RX21
LNA_
RX22
TTRU
RX1
RX2
RX3
RX4
RX_OUT1
RX_OUT2
RX_IN1
RX_IN2
TX1
TX2
TX1
TX2
COM
IN1
IN2
OUT
TX 1TX 2
TDUP
LNA_
RX11
LNA_
RX12
LNA_
RX22
LNA_
RX21
RX_OUT1
RX_OUT2
RX_IN1
RX_IN2
Note: In the figure above, for RU02 module, only TDUP module is drawn, which is necessary for schematic diagram, and
it does not mean this module has a special structure or other module. There are similar cases in the following figures, see
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them.
● Single RU02 supports S2 configuration (uses DDT and FWDR), and its set-top
output is 45w (GMSK).
RU02 has only two antenna ports, so it is necessary to input another two diversity
receivers from other modules. Under 4 diversity S1 configuration, it is necessary to add
one RU02 unit to implement another 2 ways of diversity reception. At this time, it is
advisable to adopt delay transmission diversity technology to improve the downlink
quality of the 2 ways of transmission, or the two ways of transmission can adopt DPTC
mode, and upon power combination, output large power to improve downlink quality.
TX 1TX 2PA2 PA1
TPAUTDUP
RPDC
LNA_
RX11
LNA_
RX12
LNA_
RX21
LNA_
RX22
TTRU
RX1
RX2
RX3
RX4
RX_OUT1
RX_OUT2
RX_IN1
RX_IN2
TX1
TX2
TX1
TX2
COM
IN1
IN2
OUT
TX 1TX 2PA2 PA1
TPAUTDUP
RPDC
LNA_
RX11
LNA_
RX12
LNA_
RX21
LNA_
RX22
TTRU
RX1
RX2
RX3
RX4
RX_
OUT
1RX_OUT2
RX_IN1
RX_IN2
TX1
TX2
TX1
TX2
COM
IN1
IN2
OUT
● S2 configures 4 diversity receivers + DPCT, and its set-top output power is 80w
(GMSK).
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TX 1TX 2PA2 PA1
TPAUTDUP
RPDC
LNA_
RX11
LNA_
RX12
LNA_
RX21
LNA_
RX22
TTRU
RX1
RX2
RX3
RX4
RX_OUT1
RX_OUT2
RX_IN1
RX_IN2
TX1
TX2
TX1
TX2
COM
TX 1TX 2PA2 PA1
TPAUTDUP
RPDC
LNA_
RX11
LNA_
RX12
LNA_
RX21
LNA_
RX22
TTRU
RX1
RX2
RX3
RX4
RX_
OUT
1RX_OUT2
RX_IN1
RX_IN2
TX1
TX2
TX1
TX2
COM
● S4 (does not use DDT and FWDR), and its set-top output power is 22.5w
(GMSK).
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TX 1TX 2PA2 PA1
TPAUTDUP
RPDC
LNA_
RX11
LNA_
RX12
LNA_
RX21
LNA_
RX22
TTRU
RX1
RX2
RX3
RX4
RX_OUT1
RX_OUT2
RX_IN1
RX_IN2
TX1
TX2
TX1
TX2
COM
PA2 PA1
TPAU
RPDC
TTRU
RX1
RX2
RX3
RX4
TX_OUT
RX_IN1
RX_IN0
TX1
TX2
TX1
TX2
COM
TX_OUT
Networking is conducted via RU02A.
There is no antenna and feeder interface on RU02A panel, and as compared with RU02,
its interior has one TDUP module less. So it is impossible to conduct separate
networking configuration for RU02A.
RU02A processes base band signals and conversion of RF signals. It does not have
antenna and feeder port, so it is impossible to conduct separate configuration for
RU02A. When it is unnecessary to implement 4 way diversity reception, or when it
combines with RU02 to expands its capacity from S2 to S4 or when it forms S4 with
RU02 for use , the set-top output power is 22.5w (GMSK). In this mode, S4 is
configured via two RU02, it is possible to reduce a part of the cost and lowers power
consumption.
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2.1.4.3 B8200+R8860
B8200 + R8860 implements remote radio head, which is called BBU + RRU form. It is
advisable to install it near the antenna in order to save feeder loss.
The calculation method of R8860 set-top output power is the same as that of RU60,
and no further description is provided here.
BBU+RRU can be applied in special scenarios such as indoor areas in buildings,
tunnels, high-speed railways and highways.
2.1.4.4 B8018
One cabinet of B8018 can support a maximum of 18 carriers, configures a maximum of
S666, supports the cascade of 3 cabinets, and supports a maximum of S18/18/18
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configuration.
For the specific configuration, see “ZXG_DCI_060302_V601_0705 ZXG10 B8018
Configuration Guide.doc”.
TRX Number Solution 850/900 1800/1900 Remark
1 CDU(BYPASS) 1 1
2 CDU(BYPASS) 1 1
CDU 4.4 4.6
3 CDU 4.4 4.6
4 CDU 4.4 4.6
5 CDU+CEU 7.9 8.2
CDU(BYPASS)+CENU 6.3 6.5
6 CDU+CEU 7.9 8.2
CDU(BYPASS)+CENU 6.3 6.5
7 CDU+CEU 7.9 8.2
CDU+CENU 9.7 10.1
8 CDU+CEU 7.9 8.2
CDU+CENU 9.7 10.1
9~12
CDU+CEU 7.9 8.2
3 pairs of
antennae/cell,
and increases
antenna cost
CDU+CENU 9.7 10.1 2 pairs of
antennae/cell
13~18
CDU+CENU 9.7 10.1
3 pairs of
antennae/cell,
2-level combiner
CDU+CEU+CENU 13.2 13.7
2 pairs of
antennae/cell,
and set-top at this
time is only about
2w.
2.1.4.5 B8112
One cabinet of B8112 supports a maximum of 12 carriers, configures a maximum of
S444, supports the cascade of 3 cabinets, and supports a maximum of S12/12/12
configurations.
For the specific configuration, see “ZXG_DCI_060303_V601_0705 ZXG10 B8112
Configuration Guide.doc”.
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TRX
Number Solution 850/900 1800/1900 Remark
1 CDU(BYPASS) 1 1
The same as 8018
2 CDU(BYPASS) 1 1
CDU 4.4 4.6
3 CDU 4.4 4.6
4 CDU 4.4 4.6
5 CDU+CEU 7.9 8.2
CDU(BYPASS)+CENU 6.3 6.5
6 CDU+CEU 7.9 8.2
CDU(BYPASS)+CENU 6.3 6.5
7 CDU+CEU 7.9 8.2
CDU+CENU 9.7 10.1
8 CDU+CEU 7.9 8.2
CDU+CENU 9.7 10.1
9~12 CDU+CENU 9.7 10.1
It supports a
maximum of
S12/12/12
2.1.4.6 M8202
Each cabinet of M8202 has 2 carriers, supports the maximal cascade of 3 cabinets, and
supports a maximum of S2/2/2 configuration.
M8202 does not support combiner (without built-in or external one), so it does not
support DPCT.
M8202 set-top output is always 30w (GMSK)/19w (8PSK).
Each TRX has RX/TX and separate RX diversity reception channel, so it supports the
case that the 2 carrier frequencies in one cabinet are divided into two cells, S11.
For specific configuration, see “ZXG_DCI_060305_V601_0706 ZXG10 M8202
Configuration Guide.doc”.
2.1.4.7 M8206
M8206 is modular base station. In principle, for site type S11, S111 or omni site O1,
O2 site type, it is recommended to use DPCT. For site type S22, S222, it is not
recommended to use DPCT (carrier frequency is doubled), and record set-top 30w
(GMSK). For S444 type configuration, it is not recommended to use DPCT, and if it is
necessary to reach set-top power 30w (GMSK), the number of antennae configured
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should be doubled, otherwise, set-top power is 13w.
For indoor coverage, generally receiver diversity is not necessary. For outdoor
coverage, generally receiver diversity is necessary.
Configuration
Type
Enhancement
Technique
CTU
Quantity RTU Quantity
ECU
Quantity
EFU
Quantity
Antenna
Quantity
Set-top
Output
Power
O1 - 1
1 (single carrier
frequency
module)
0 0 1 30
O1 DPCT 1 1 1 0 1 53
O1 DDT/receiver
diversity 1 1 0 0 2 30
O1 DPCT/4diversity
reception 1 1 0 1 4 53
O2 - 1 1 1 0 1 13.5
O2 Receiver diversity 1 1 0 0 2 30
O2 DPCT 1 2 2 0 2 53
O2 DDT/receiver
diversity 1 2 2 0 2 13.5
O4 receiver diversity 1 2 2 0 2 13.5
O4 4 way receiver
diversity 1 2 0 0 4 30
S111 - 1
2 (1 single
carrier
frequency
module)
0 0 3 30
S111 DDT/receiver
diversity 1 3 0 0 6 30
S111 DPCT 1 3 3 0 3 53
S11 - 1 1 0 1 4 30
S22 - 1 2 2 0 2 13.5
S22 Receiver diversity 1 2 0 0 4 30
S222 - 1 3 3 0 3 13.5
S222 Receiver diversity 1 3 0 0 6 30
S444 Receiver diversity 2 6 6 0 6 13.5
For specific configuration, see “ZXG_DCI_060304_V611_0809 ZXG10 M8206
Configuration Guide.doc”.
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2.1.4.8 BTSV2 TRX Number Solution 850/900 1800/1900
BTS V2 1 CDU 4.4 4.6
CDU(BYPASS) 1 1
2 CDU 4.4 4.6
CDU(BYPASS) 1 1
3 CDU 4.4 4.6
4 CDU 4.4 4.6
5~12 CDU+CEU 7.9 8.2
2.1.4.9 OB06 TRX Number Solution 850/900 1800/1900
OB06 1 CDU(BYPASS) 1 1
CDU 4.4 4.6
2 CDU(BYPASS) 1 1
CDU 4.4 4.6
3 CDU 4.4 4.6
4 CDU 4.4 4.6
5 CDU+CEU 7.9 8.2
6 CDU+CEU 7.9 8.2
2.1.4.10 BS30
BS30 needs to deduct 1dB duplexer loss.
2.1.4.11 BS21 TRX Number Solution 850/900 1800/1900
BS21 1 ECDU 1 1
2 CDU(BYPASS) 1 1
4 CDU 4.4 4.6
2.1.5 Coverage Enhancement Technique
2.1.5.1 DPCT
Dual Power Combining Transmission (DPCT), namely, two transmitters send out the
same burst pulse at the same time, and forms via combiner one carrier in form, thereby
getting the maximum transmitting gain of 3dB. The nominal gain of DPCT to downlink
is 2.5dB.
DPCT and DDT in the following paragraph cannot be used at the same time.
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When DPCT technology is adopted, the carrier frequency quantity needs to be doubled,
and single site cost is increased. However, in term of network size, it is possible to
reduce the quantity of sites. It is usually used together with uplink coverage
enhancement technique TMA, or FWDR, IRC.
2.1.5.2 DDT
Downlink delay diversity transmission refers to the case in which two transmitters send
the same signal within a short delay, and the two transmitters are used as one “virtual
transmitter”, and mobile phone terminal receives the two signals which carry the same
information and completely different interference noises, and conducts diversity
processing to strengthen downlink signals. Time domain delay value can be set at
OMC client with step-length being 0.125, and the maximum step-length can reach ± 5
fields. It can get the maximum signal gain of 3dB. The nominal gain of DDT to
downlink is 3dB. DDT and DPCT cannot be used at the same time.
When DDT technology is adopted, the carrier frequency quantity needs to be doubled,
and single site cost is increased. However, in term of network size, it is possible to
reduce the quantity of sites. It is usually used together with uplink coverage
enhancement technique TMA, or FWDR, IRC.
2.1.5.3 FWDR
FWDR (Four Way Diversity Receive) technology, namely, each transmission channel
has 4 ways of diversity reception, and relative to common 2 way diversity, FWDR
brings an additional gain of 2~5dB. Generally we get the uplink gain of 2dB. At this
time, the general 2 way diversity gain 3dB is also calculated together, that is, the real
diversity gain is 5dB.
FWDR requires 4 pairs of antennae for each cell, and the cost of antenna and feeder of
the single site has doubled. However, in terms of the whole network size, it is possible
to reduce the quantity of sites. It is usually used together with downlink coverage
enhancement technique DDT, DPCT or jumper or combiner.
2.1.5.4 IRC
In all received signals, select from the RX of DTRU the signal with the largest power.
The comparison results are generated in DTRU and are combined into relatively large
received signals for further demodulation. That is the maximum ratio combination
technology MRC.
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IRC (Interference Rejection Combining) function can be thought to be a kind of more
advanced diversity reception function, which can improve the quality of uplink signal
and gain. Via software combination, it is possible to improve C/I gain by 11dB and to
get the gain of 5-6dB in typical urban area. IRC requires two way receiving antennae
(receiver diversity), and we get generally 3dB for IRC gain.
The following table sums up how the current SDR, V3 and V2 equipment support the
above four coverage enhancement techniques.
Equipment
Type DPCT DDT IRC FWDR
RU02 Y Y Y Y
RU60 N Y Y Y
R8860 N Y Y Y
B8018 Y Y Y Y
B8112 Y Y Y Y
M8202 N Y Y Y
M8206 Y Y Y Y
BTSV2 N N N N
OB06 N N N N
BS30 N N N N
BS21 N N N N
2.2 MS Transmission Power
According to GSM protocol, MS transmission power is specified according to different
Classes:
Power
Class
GSM 900 Nominal
Maximum output
power
DCS 1800
Nominal Maximum
output power
PCS 1900
Nominal Maximum
output power
1 - - - - - - 1 W (30 dBm) 1 W (30 dBm)
2 8 W (39 dBm) 0.25 W (24 dBm) 0.25 W (24 dBm)
3 5 W (37 dBm) 4 W (36 dBm) 2 W (33 dBm)
4 2 W (33 dBm)
5 0.8 W (29 dBm)
Currently most mobile phones in the market support 4 types of GSM900 terminals, 2W
(33dBm).
The terminal that supports DCS1800 is Type 1, 1W (30dBm).
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In conducting link budget, do not consider power control. Calculate according to the
standard that the maximum transmission power of GSM900 MS is 33dBm, and the
maximum transmission power of GSM1800 MS is 30dBm.
2.3 Sensitivity
2.3.1 BTS Receiver Sensitivity
2.3.1.1 Definition of Receiver Sensitivity
Receiver sensitivity refers to the minimum signal power that the receiver input end
must reach in order to ensure that signals can be successfully detected and decoded (or
to maintain the necessary FER).
2.3.1.2 Calculation of Receiver Sensitivity
The formula for calculating receiver sensitivity is:
Sin (dBm) = hot noise power + system noise coefficient + signal to noise ratio
Where,
1. Sin (dBm) is receiver sensitivity.
2. The formula for calculating hot noise power is K*T*BRF (dBm).
● K is Boltzmann constant (W/Hz/K) and it is equal to 1.381 x 10-23
W/Hz/K.
● T is temperature (K). Room temperature is 290K.
● BRF is RF carrier bandwidth (Hz), which is 200000Hz.
Hot noise power = 10 x log (1.381 x 10-23
W/Hz/K x 290K x 200000Hz x 1000mW/W)
= -121 dBm
System noise coefficient NF
When the signal passes the receiver, the receiver adds noise to the signal, and noise
coefficient is a method for measuring the added noise. In value, it is equal to input
signal to noise ratio divided by output signal to noise ratio. The formula is:
input
out
SNRF
SNR= (2.2.1-1)
It characterizes the degradation degree of the signal to noise ratio (SNR) after signal
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passes the system, the ideal scenario is the system has no additional noise, and it only
amplifies input signal and noise at the same time, and at this time, F=1. However in a
real case, this scenario cannot happen. In active network, the noise increases due to the
gain just as the signal does and there are also additional hot noise and shot noise
generated by active components
For passive network whose attenuation is L, noise is kTB, and output signal changes
into 1/L of the input. According to the definition in formula (2.2.1-1), at this time, the
noise coefficient is L. So after the signal passes the system, SNR degrades, F>1.
Generally we, we habitually use dB to express this coefficient, namely
10logNF F= (2.2.1-2)
It is usually the case that we want to the noise coefficient of the whole system when we
know the noise feature of the component. The figure below provides a typical cascade
system diagram, which F, G respectively stand for the noise factor, gain and bandwidth
of various parts. In this way, the noise coefficient of whole system is:
321 1
1 1 2
1
1 11 n
n
i
i
F FFF F
G G GG
−
=
− −−= + + + +
∏L (2.2.1-3)
From this formula it is easy to see that the first noise coefficient has the largest impact
on the whole noise coefficient, so in receiver, the first one tends to be low noise
amplifier (LNA).
In formula (2.2.1-3), denominator
1
1
n
i
i
G−
=
∏ can actually be seen as the total gain of
the preceding n-1 ones (here G is not converted into dB).
In ZTE GSM_BTS receiving system, noise coefficient is approximately NF (dB) =
2.5.Where, the noise coefficient of the front end duplexer + LNA is 2, and its gain is
19.2. The noise coefficient of the back end receiver is 10.
Eb/No (dB): Minimum signal to noise ratio required in demodulation. For GMSK, it
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should not be bigger than 9dB. Eb/No of ZTE GSM system can reach 7dB.
To sum up the above, BTS receiver sensitivity=-121+2.5+7=-111.5dBm.
2.3.1.3 BTS Receiver Sensitivity List
The following table shows the nominal the static receiver sensitivities of various
products. In link budget, calculate according to static nominal sensitivities.
BTS TYPE 850M 900M/EGSM 1800M 1900M
RU02 -112 -112 -112 -112
RU60 -112 -112 -112 -112
R8860 -112 -112 -112 -112
B8018 -112 -112 -112 -112
B8112 -112 -112 -112 -112
M8202 -112 -112 -112 -112
M8206 -112 -112 -112 -112
BTS V2 -110 -110 -110 -110
OB06 -110 -110 -110 -110
BS30 -110 -110 -110 -110
BS21 -110 -110 -110 -110
The following table shows the BTS receiver sensitivities under static, TU50 no SFH,
HT100 no SFH and RA250 no SFH conditions that are provided by the R&D
Department. Where, the R&D Department has not provided GSM1800 static receiver
sensitivity, and here calculate it according to GSM900 temporarily.
GSM900 GSM1800
Static
TU50
no
SFH
HT100
no SFH
RA250
no SFH Static
TU50
no SFH
HT100
no SFH
RA250
no SFH
TCH/FS -112 -104 -104 -104 -112 -104 -104 -104
PDTCH/CS1 -113.5 -104 -103 -104 -113.5 -104 -103 -104
PDTCH/CS2 -111.5 -100 -99 -101 -111.5 -100 -99 -101
PDTCH/CS3 -110.5 -98 -96 -98 -110.5 -98 -94 -98
PDTCH/CS4 -105 -90 * * -105 -88 * *
PDTCH/MCS1 -111.5 -102.5 -102 -103 -111.5 -102.5 -101.5 -103
PDTCH/MCS2 -111 -100.5 -100 -100.5 -111 -100.5 -99.5 -100.5
PDTCH/MCS3 -110 -96.5 -95.5 -92.5 -110 -96.5 -94.5 -92.5
PDTCH/MCS4 -107.5 -91 * * -107.5 -90.5 * *
PDTCH/MCS5 -104 -96.5 -95 -96 -104 -95.5 -93 -96
PDTCH/MCS6 -103 -94 -91 -91 -103 -94 -85.5 -91
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PDTCH/MCS7 -100.5 -89 -86** -87** -100.5 -87 * -87**
PDTCH/MCS8 -98.5 -84 -81.5** * -98.5 -86.5** * *
PDTCH/MCS9 -97.5 -80 * * -97.5 -83** * *
2.3.2 MS Receiver Sensitivity
MS receiver sensitivity is the minimum signal power necessary to be reached in order
to ensure that signal can be successfully detected and decoded.
Generally MS static receiver sensitivity is required to be -102dBm.
The following table shows the nominal indices of the MS receiver sensitivities under
static, TU50 no FH and TU50 idea FH conditions with reference to those of other
manufacturers. GSM900 GSM1800
Static TU50/TU50 idea FH Static TU50/TU50 idea FH
Voice -102 -102
CS1 -102 -102/-102 -102 -102/-102
CS2 -102 -98/-99 -102 -98/-98
CS3 -102 -96/-97 -102 -96/-96
CS4 -99 -89/-89 -99 -86/-86
MCS1 -104 -102.5/-103 -104 -102.5/-103
MCS2 -104 -100.5/-101 -104 -100.5/-101
MCS3 -104 -96.5/-96.5 -104 -96.5/-96.5
MCS4 -101.5 -91/-91 -101.5 -90.5/-90.5
MCS5 -98 -93/-94 -98 -93.5/-93.5
MCS6 -96 -91/-91.5 -96 -91/-91
MCS7 -93 -84/-84.5 -93 -81.5/-80.5
MCS8 -90.5 -83/-83 -90.5 -80/-80
MCS9 -86 -78.5/-78.5 -86 n.a/n.a
Like voice, in calculating data service, including the corresponding MS receiver
sensitivity in the calculation, thereby getting the minimum required level and design
level.
2.3.3 Gain of TMA to BTS Receiver Sensitivity
Tower amplifier includes two types: One-way tower amplifier (uplink, it is usually
called TMA) and two-way tower amplifier (uplink/downlink, usually called Booster).
Generally in a project, TMA is often used.
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TMA is a network equipment that improves receiving performance of the base station
by adding, at the front end of receiving system of the base station, namely, close to the
lower part of the antenna, a low noise and high linearity amplifier used to amplify
uplink signals to improve the level gain of the base station uplink. In technical
principle, TMA improves receiver system sensitivity of the base station by lowering the
noise coefficient of the receiver system of the base station. TMA improves the uplink
receiver sensitivity at the edge of coverage area, can effectively enlarge the uplink
receiving range of the base station and improves uplink/downlink balance.
Like TMA, Booster can lower the noise coefficient of the receiving end on uplink and
improve base station receiver sensitivity. As a power amplifier is added on downlink, it
can also improve downlink coverage.
The general performance parameters of TMA are as follows:
Parameter Index
Gain 12dB
TMA noise coefficient 1.6dB
Insertion loss 0.5dB
When TMA is introduced, it is necessary to increase bias T connector. This bias T
connector functions to isolate direct current within RF path and to isolate RF within
direct current path. Direct current is input from power distribution unit input and is
conveyed via coaxial cable to antenna/tower amplifier, and to supply power to low
noise amplifier. T connector insertion loss is 0.3dB.
Additionally, when TMA is introduced, it is necessary to increase two Din connectors
and a piece of 1/2 soft jumper (usually 2m), which are used to connect the main feeder
cable and tower amplifier. The loss of the two Din connector is 2 x 0.05dB. The loss of
2m 1/2 soft jumper is calculated to be 2m x 1/2 jumper per meter loss.
According to formula 2.2.1-3, it is possible to calculate the system noise coefficient
when TMA is added and when TMA is not added.
Suppose:
The base station noise coefficient = 2.5dB, and it is 1.7783 when it is converted into
non-dB.
The noise coefficient (before TMA is added) of feeder connector is equal to feeder
connector loss (before TMA is added) = 3dB, and it is 1.99526 when converted into
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non-dB.
Feeder connector gain (before TMA is added) is the reciprocal (non dB) of the loss,
0.501187, namely, dB calculation -3dB.
The noise coefficient of feeder connector (when TMA is added) is equal to feeder
connector loss (when TMA is added) = 3+0.3+0.05 x 2 +0.1 = 3.5dB, and is 2.23872
when converted into non dB.
Feeder connector gain (when TMA is added), is the reciprocal (non dB) of loss, and is
0.446684, namely, dB calculation -3.5dB.
TMA noise coefficient1.6dB is 1.44544 when converted into non dB.
TMA gain 12dB is 15.8489319 when converted into dB.
All take antenna port as reference points.
When TMA is not added
Regard BTS and feeder (containing connector) as one cascade system. For uplink, the
first level is feeder and the second level is BTS. At this time, the equivalent noise
coefficient of antenna port is calculated according to the following formula (include
them all according to non dB value):
NF1 = feeder loss when TMA is not added + (BTS noise coefficient-1)/feeder gain
when TMA is not added
Then,
NF1=3.54813
When converted into dB for expression, then
NF1=5.5dB
When TMA is added
Regard BTS, feeder (containing connector) and TMA as one cascade system. For
uplink, the first level is TMA, and the second level is feeder and the third level is BTS.
At this time, the equivalent noise coefficient of antenna port is calculated according to
the following formula (include them all according to non dB value):
NF2= TMA noise coefficient + (the feeder loss when TMA is added -1)/TMA gain +
(BTS noise coefficient-1)/(feeder gain when TMA is added *TMA gain)
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Then,
NF2=1.63353
If converted into dB for expression, then
NF2=2.131278dB
Noise coefficient gain to the system when TMA is added
TMA Contribution = NF1-NF2=5.5-2.131278=3.368722dB
It can be seen from the above calculation process that:
The gain obtained by using tower amplifier is related to the following several factors:
feeder cable loss, amplifier gain, amplifier noise coefficient, base station noise
coefficient. The bigger the feeder cable loss is, the bigger the amplifier gain is; the
smaller the amplifier noise coefficient is, the bigger the base station noise coefficient is;
and the bigger the function of using tower amplifier to improve the whole system noise
coefficient is. Contrarily, the smaller the gain of improving the whole system noise
coefficient is.
Additionally, it is necessary to note that: Tower amplifier mainly functions to improve
uplink coverage, but in fact it is an active component which objectively increases
interference with downlink, equivalent to increasing downlink load and reducing the
real capacity of downlink. In link budget, downlink needs to increase 0.5dB insertion
loss generated by introduction of TMA.
In the system, tower amplifier is not suitable for use in the environment of urban area
or dense city area. TMA is suitable for use in suburban area, vast rural areas and on
highways.
2.4 Feeder, Jumper and Connector
2.4.1 Without Tower Amplifier
The cables leading out set-top box are all installed with DF connectors and DM
connectors are installed at both ends of the soft jumper.
Jumper
Set-top—discharger (indoor jumper), top of main feeder— antenna (outdoor jumper)
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For the sake of simplification, the length of this part of jumper is generally 5m by
default.
The following table shows the typical loss value of every 100 m jumper:
Feeder Type 850/900 1800/1900 Unit
1/2 jumper 11.2 16.6 dB/100m
Note: The feeder cable loss of every 100 m jumper listed here is all based on the SPEC
of Hansen product. There may be a difference between the loss here and that of feeder
cable produced by other manufacturers, and the loss in a real case prevails. It is the
same in the following.
Main feeder
Generally it is advisable to use 7/8’’feeder cable. But when feeder loss is bigger than
3dB, it is recommended to use thicker feeder cable to reduce feeder loss. In terms of
cost influence, it increases feeder cable cost of single site, but in terms of network size,
it is possible to reduce the quantity of sites.
In consideration of the fact that a part of main feeder leads to the equipment room in
usual conditions, so it is advisable to get antenna height + 5m for the length of the main
feeder.
The following table shows the typical loss value of every 100 m main feeder:
Feeder Type 850/900 1800/1900 Unit
7/8’’ Feeder 3.88 5.75 dB/100m
1-1/4’’ Feeder 2.77 4.16 dB/100m
1-5/8’’ Feeder 2.29 3.47 dB/100m
Fiber 0 0 dB/100m
Connector
2 DM connectors of indoor jumper, 2 DM connectors of outdoor jumper, 2 pieces of
7/8 main feeder DF connectors, a total of 6
For the loss of each connector, various frequency bands all get 0.05dB/piece, and when
tower amplifier is not added, the total connector loss is 0.3dB.
Discharger
0.2dB (DM/DF connectors at both ends are included).
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2.5 Antenna
2.5.1 BTS Antenna Gain
Determine BTS antenna gain according to BTS antenna model selection principle.
Area Antenna Gain (dBi)
Dense urban 15.5~17
Urban area 15.5~17
Suburban area 17~18
Rural area 18~20
Highway or long and narrow valley 18~20 (narrow beam)
High mountains and hills 17~18
For GSM1800, to maximize 1800M coverage, it is advisable to select the antenna
whose gain is 1~2dB bigger than 900.
For dual frequency network, it is advisable to select dual frequency antenna to save
antenna installation space. At this time, pay attention to whether the parameters of the
dual frequency antenna can meet the requirement of the two frequency bands, and it is
necessary to consult the SPEC of this antenna.
2.5.2 BTS Antenna Height
Determine BTS antenna height according to BTS antenna model selection principle.
The general principle is:
Wireless Environment Recommended Height (m)
DU 25
MU 30
SU 35
RU 45
Road 45
The antenna height here refers to the height from the center point of the antenna panel
to the ground.
If it is roof tower or bole, the antenna height = the height from the center point of the
antenna panel to the house top surface + building height.
If it is ground tower, the antenna height = the height from the center point of the
antenna panel to the ground.
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The antenna height calculated here should be in fact understood to be absolute height.
In simulation, it is advisable to consider landform (height) information and calculate
relative height. For the difference between the relative height and absolute height, see
“Simulation FAQ”.
It is necessary to note that:
Network planning can only provide antenna height but cannot provide the type and
height of the tower, so it is necessary for the International Market Department to make
a comprehensive consideration. Especially it is necessary to consider the height
required by micro wave at the same time.
The antenna height in link budget is an absolute value while relative value is used in
the simulation, so there is surely a difference between the coverage radius in simulation
and that of link budget. It is particularly obvious in hill and mountain areas where there
are relatively large ups and downs of landforms. If the customer requests to provide the
reasons, it is advisable to make explanations from this aspect.
2.5.3 MS Antenna Gain
If it is general mobile network, in using mobile phone terminal, then MS antenna gain
is generally 0.
If it is WLL network, the scenarios should be considered in two cases:
If the terminal of WLL network is the same as general mobile phone, it is also a phone
with mobility, and MS antenna gain is 0.
If the terminal of WLL network is a fixed station, then the antenna gain of a fixed
station is not 0. Generally speaking, if it is the indoor antenna of a fixed station, the
gain is generally about 2dBi. If it is the outdoor antenna of a fixed station, the gain is
generally 9~12dBi. It is necessary to clarify it in the planning.
In addition to the fact the gain of WLL indoor antenna and that of WLL outdoor
antenna are different, there are also others things that call for attention. When we adopt
indoor antenna, in calculating minimum required level, we need to deduct building
penetration loss and handle it according to indoor conditions.
When we adopt outdoor antenna, in calculating minimum required level, we do not
deduct building penetration loss and handle it according to outdoor conditions.
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2.5.4 MS Antenna Height
If it is general mobile network, in using mobile phone terminal, then MS antenna
height is generally thought to be 1.5m.
It is WLL network, it is necessary consider it in two cases:
1. If the terminal of WLL network is the same as general mobile phone, it is also a
mobile phone with mobility, and then MS antenna height is generally thought to
be 1.5m.
2. If the terminal of WLL network is a fixed station, heights for fixed station
antenna are different. Generally speaking, if it is the indoor antenna of the fixed
station, the antenna height is also generally about 1.5m. If it is the outdoor
antenna of the fixed station, the antenna height is generally 3m~10m. It should
be firstly clarified before planning.
2.5.5 Diversity Gain
The diversity gain here refers to 2 way diversity gain, as 2 way receivers bring uplink
gain. If it is 4 way diversity receptions, it is necessary to add FWDR gain on this 2 way
diversity gain.
Generally diversity gain gets 3dB.
2.6 Margins
2.6.1 Rayleigh Fading (Fast Fading) Margin
Rayleigh fading refers to the case in which multi-path interference is caused on the
ground and standing wave field is formed due to the fact that propagation is reflected
by spurious bodies (mainly human-made buildings) or natural barriers (mainly trees)
within 50~100 wavelengths around the mobile station. When the mobile phone passes
this standing wave, the received signals undergo short fading with a relatively large
fluctuation of field intensity. The features of this kind of fading comply with Rayleigh
distribution, so it is called Rayleigh fading and it is also called fast fading.
Under the impact of multi-path effect, it is the receiving level necessary for reaching
the voice quality when there is only the internal noise of receiver. The introduced
addition volume is called fading margin.
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Generally speaking, 3dB is obtained for voice and data.
2.6.2 Shadow Fading (Slow Fading) Margin (Log-normal Fading Margin)
Due to the impact of buildings and topographic relief and landform, the obstruction of
these barriers causes electromagnetic shadow effect, resulting in the intensity fading of
received signals, which is called shadow fading. The probability intensity distribution
of this kind of fading complies with lognormal distribution, so it is also called
Log-normal Fading.
Generally speaking, the propagation model can only describe the change of the local
mean value of the signal level. That is to say, at this time, the coverage probability at
the cell edge is 50%. To ensure that base station covers the cell edge with a certain
probability, the base station must reserve certain transmission power to overcome
shadow fading, and the reserved power is shadow fading margin.
The calculation of shadow fading margin is related to several factors: Edge (area)
coverage probability, standard variance and path loss coefficient.
2.6.2.1 Coverage Probability
In the figure below, X stands for base station and the little black dot stands for mobile
phone.
We review the receiving level value of a certain point near the base station, and by
conducting statistics on this value within a period of time, it is possible to get a series
of level values, and then we seek the mean value X0 and the standard deviation sigma.
If our measure data is sufficient, we can get the following curve:
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Where, the horizontal coordinate is level value and the vertical coordinate is the
proportion that this level occupies. When the level value is x0, the proportion it
occupies is the largest, and the sum of the percentages of all points should be 1.
We set a threshold value Xthresh, and when the level value of this point is bigger than
Xthresh, we think this point is “covered”.
Suppose Xthresh>X0, we get the coverage probability of this point by adding the
percentages to which the level values in the shadow correspond.
It can be known by analysis that,
When the mobile phone is relatively near to base station, X0 > Xthresh, and the
coverage probability is relatively big, >50%
When the mobile phone is relatively far from the base station, X0<Xthresh, the
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coverage probability is relatively small, <50%
If there is a point X0 = Xthresh, the coverage probability is 50%
For every point on the circumference, we can get its coverage probability value in the
same way. Here we suppose the coverage probability of every point on the
circumference is the same, and we can make an irregular circumference. The
probability of site on the circumference whose level value is bigger than Xthresh is the
edge coverage probability.
The probability of the points of the whole area within the circumference whose level is
bigger than Xthresh is area coverage probability.
2.6.2.2 Calculation of Shadow Fading Margin
Suppose that the coverage probability of each point on the circumference we have
drawn is 50%, namely, every point on the circumference X0 = Xthresh (solid line).
There is another circumference, whose edge coverage probability is 75% (dash line).
Edge Reliability:50%
Edge Reliability:75%
It can be known from the above analysis that, X0 > Xthresh, and for shadow fading
margin whose edge coverage probability is 75%, X0-Xthresh.
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According to Jake’s Single Cell Equation
Where,
Px0 (R) is edge coverage probability.
Xthresh-X0 is the shadow fading margin that reaches this edge coverage probability.
Sigma is the standard variance of shadow fading.
When Fade Margin = Xthresh-X0=0, Px0(R) = 50%.
It is possible to get the correspondence relation as shown in the figure below:
Px0(R)=1/2-1/2erf((Xthresh-X0)/(sigma*sqrt(2)))
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2.6.2.3 Conversion between Edge Coverage Probability and Area Coverage Probability
The relation between area coverage probability and edge coverage probability is shown
in the formula below:
Where,
1/2-1/2erf (a) in the yellow background is in fact edge coverage probability.
Fu=1/2-1/2erf(a)+1/2exp((1-2ab)/b^2)*[1+erf(ab-1)/b]
a=(Xthresh-X0)/(sigma*sqrt(2))
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n is path loss coefficient, its value is 3~4, and the value is generally 3.5.
Generally speaking, under the same condition, area coverage probability is bigger than
edge coverage probability. To understand it in physics, for measuring within cell
coverage scope and measuring at cell edge, the probability of reaching the same
Xthresh based on plane is a surely bigger.
Area coverage probability can be quantified, and the method is to conduct drive test
within the cell coverage scope, and count the probability of various points on the drive
test line whose level value is bigger than Xthresh.
Relatively speaking, edge coverage probability cannot be quantified. So generally
carriers take area coverage probability as design conditions.
In network design, it is necessary to consider the requirement for edge (area) coverage
probability, so it is necessary to calculate shadow fading margin according to Jack
formula.
2.6.2.4 Quick-finding Table for Common Shadow Fading Margin
Below is a quick-finding table for shadow fading margin when the path loss coefficient
is 3.5 in general condition.
Area Type Area Coverage
Probability
LNFmarg (dB)
Dense Urban Sigma=10dB 75% 1
85% 5
90% 7.7
95% 11.7
99% 19
Medium Urban Sigma=8dB 75% 0
85% 3.3
90% 5.5
95% 8.7
99% 14.7
Suburban +Rural +Road
Sigma=6dB
75% 0
85% 1.6
90% 3.4
95% 5.9
99% 10.5
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2.6.3 Interference Margin
We know that one of the essential elements of calculating receiver sensitivity is the
signal to noise ratio, namely, the ratio between signal and noise, which is expressed as
C/N here. When there is frequency multiplex, receiving power had to cope with both
noise and interference, which is expressed as C/(N+I). In network design, it is
necessary to consider interference margin.
Interference margin is related to frequency multiplex and system load. GSM system is
a typical interfered and limited system. Co-frequency and adjacent-frequency
interferences caused by unavoidable frequency multiplex can be reduced by using
technologies such as frequency hopping, dynamic power control and DTX, but it is still
impossible to completely eliminate them. So it is recommended to consider 3dB
interference margin in designing network.
In link budget of voice and data services, we get 3dB for interference margin.
2.6.4 Body Loss
Body loss refers to the loss caused signal block and absorption due to the fact that
handheld phone is very close to human body. Body loss depends on the position of the
mobile phone relative to human body. When handheld phone is at the waist and
shoulders of the user, the field intensities of its received signals respectively lower by
4~7dB and 1~2dB as compared with the case in which antenna is several wavelength
away from human body.
In link budget of voice service, its value is generally 3dB. In link budget of data service
conducted with data card, its value is 0dB.
2.6.5 Building Penetration Loss
Building penetration loss refers to the attenuation undergone by radio wave when it
passes the external structure of a building, which is equal to the difference between the
field intensity median of the outdoor area of the building and that of the indoor area of
the building.
Building penetration loss is close related to building structure, types and sizes of doors
and windows, and building floors. Penetration loss varies with the change of the
heights of building floors.
The higher the frequency band is, the stronger the radio wave penetration capability is,
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but the weaker the radio wave diffraction capability is. The indoor radio wave can be
seen as the sum of penetration component and diffraction component.1800M
penetration capability is stronger than that of 900M, but its diffraction capability is
lower than that of 900M. Part of the signal of 1800M entering the indoor area
penetrates out through the wall, leading to uneven distribution of signals in indoor
space, showing a very big difference of signal levels in the same position. So generally
we reserve more building penetration losses for 1800M.The penetration loss value of
1800M is generally about 5dB bigger than that of 900M in area of the same class.
Area Classification 900M loss (dB) 1800M loss (dB)
Dense urban area 18~22 23~27
General urban area 15~20 20~25
Suburban area and
rural area
10~15 15~20
2.6.6 Car Penetration Loss
Car loss is generally 6~8dB.
2.7 Recommended Minimum Required Level and Design Level
When the customer has not definitely put forward acceptance level, it is necessary to
take the minimum required level as the acceptance level and calculate design level
according to it. The recommended values of the minimum required levels of 900M and
1800M SSmin_req and design level SSdesign are respectively as follows.
2.7.1 900M
Area Type Coverage
Probability
BPL(dB) CPL(dB) SSmin_req
(dBm)
LNFmarg
(dB)
SSdesign
(dBm)
Dense Urban
Sigma=10dB
75% 20 -73 1 -72
85% 20 -73 5 -68
90% 20 -73 7.7 -65.3
95% 20 -73 11.7 -61.3
99% 20 -73 19 -54
Medium
Urban
Sigma=8dB
75% 15 -78 0 -78
85% 15 -78 3.3 -74.7
90% 15 -78 5.5 -72.5
95% 15 -78 8.7 -69.3
99% 15 -78 14.7 -63.3
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Suburban
Sigma=6dB
75% 13 -80 0 -80
85% 13 -80 1.6 -78.4
90% 13 -80 3.4 -76.6
95% 13 -80 5.9 -74.1
99% 13 -80 10.5 -69.5
Rural
Sigma=6dB
75% 10 -83 0 -83
85% 10 -83 1.6 -81.4
90% 10 -83 3.4 -79.6
95% 10 -83 5.9 -77.1
99% 10 -83 10.5 -72.5
Road
Sigma=6dB
75% 8 -85 0 -85
85% 8 -85 1.6 -83.4
90% 8 -85 3.4 -81.6
95% 8 -85 5.9 -79.1
99% 8 -85 10.5 -74.5
Note: Indoor level is considered for all DU/MU/SU/RU. In-car level is considered for all Roads.
2.7.1.1 1800M
Area Type Coverage
Probability
BPL(dB) CPL(dB) SSmin_req
(dBm)
LNFmarg
(dB)
SSdesign
(dBm)
Dense Urban
Sigma=10dB
75% 25 -68 1 -67
85% 25 -68 5 -63
90% 25 -68 7.7 -60.3
95% 25 -68 11.7 -56.3
99% 25 -68 19 -49
Medium
Urban
Sigma=8dB
75% 20 -73 0 -73
85% 20 -73 3.3 -69.7
90% 20 -73 5.5 -67.5
95% 20 -73 8.7 -64.3
99% 20 -73 14.7 -58.3
Suburban
Sigma=6dB
75% 18 -75 0 -75
85% 18 -75 1.6 -73.4
90% 18 -75 3.4 -71.6
95% 18 -75 5.9 -69.1
99% 18 -75 10.5 -64.5
Rural
Sigma=6dB
75% 15 -78 0 -78
85% 15 -78 1.6 -76.4
90% 15 -78 3.4 -74.6
95% 15 -78 5.9 -72.1
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99% 15 -78 10.5 -67.5
Road
Sigma=6dB
75% 8 -85 0 -85
85% 8 -85 1.6 -83.4
90% 8 -85 3.4 -81.6
95% 8 -85 5.9 -79.1
99% 8 -85 10.5 -74.5
Note: Indoor level is considered for all DU/MU/SU/RU. In-car level is considered for all Roads.
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3 Link Budget
3.1 Link Budget Process
When we get to know the meanings of various parameters in link budget process, then
we need to conduct uplink/downlink power balance budget. The main aim of this
process is to budget whether uplink/downlink is balanced. If uplink is limited, it is
necessary to consider suitably reducing BTS transmission power, or adopt uplink
coverage enhancement technique. If the downlink is limited, it is necessary to consider
increasing BTS transmission power, or adopt other downlink coverage enhancement
techniques.
3.1.1 Downlink Budget
Parameter Sign Unit
Carrier frequency
transmission power
A dBm
Combiner loss B dB
BTS set-top output power C=A-B dBm
Feeder connector loss D dB
BTS antenna gain E dBi
MS antenna gain F dBi
SSdesign G dBm
MS receiver sensitivity H dBm
Various margins I=G-H dB
Downlink enhancement
technique
J dB
Downlink maximum
allowed path loss
K=C-D+E+F-G+J dB
Where, various margins include shadow fading margin, fast fading margin, interference
margin, body loss, building penetration loss and car loss.
3.1.2 Uplink Budget
Parameter Sign Unit
MS transmission power A dBm
MS antenna gain B dBi
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BTS antenna gain C dBi
Diversity gain D dB
Feeder connector loss E dB
BTS receiver sensitivity F dBm
Contribution of TMA to
sensitivity
G dB
Various margins H=SSdesign-MSsens dB
Uplink enhancement
technique
I dB
Uplink maximum allowed
path loss
J=A+B+C+D-E-F+G-H+I dB
Where, various margins include shadow fading margin, fast fading margin, interference
margin, body loss, building penetration loss and car loss, and hey keep consistent with
calculated downlink margins.
3.1.3 Equivalent Maximum Allowed Path Loss
Compare the maximum allowed path losses of the uplink and downlink, and select the
smaller one as the equivalent maximum path loss of the whole link. Generally speaking,
the link is thought to be basically balanced when the difference between the uplink and
the downlink.
3.2 Link Budget Tool V3.3 (Promoted for Use)
Description is to be provided after LinkBudget.exe tool is officially released.
3.3 Link Budget Tool V3.2.X (Not Promoted from Now on)
In V3.2.X version of Excel-version link budget tool mainly conducts link budget for
voice service and does not involve data service. The excel version tool is not so
convenient and standardized, it is difficult to maintain it, so when the exe version link
budget tool is launched, the previous excel tool ceases to be used.
“GSMLinkBudgetTool.exe”, the link budget tool in EXE version, considers
GPRS/EDGE, has more friendly interface and is more convenient for use, so planning
engineers are required to use tool. To control its copyright, it is necessary to apply for
the license.
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3.3.1 Tool Structure
The whole tool programmed on the basis of VBA macro and function.
It includes 13 Sheets. Where, input condition is reflected in Input, and output is
reflected in Link Budget (Complete) Table and Link Budget (Simple) Table. The
functions of various tables are respectively described below.
3.3.1.1 Version
This table provides the officially released version information, including releasing time,
maker, reviewer and changed items.
Pay attention to the latest version.
This sheet is generally visible.
3.3.1.2 Specification
This table provides, in eye-catching fonts, the key points that call for attention
precautions before using this tool. Use it strictly according to specification description,
otherwise link budget result can be made incorrect.
This sheet is generally visible.
3.3.1.3 Input
The setting of all link budget parameters is conducted in Input table. Where, some
parameters are links in other tables, which are values by default. If it is necessary to
make temporary change, it is advisable to make change in Input table. When the tool is
opened next time, the tool restores default values. If it is necessary to make permanent
change, or to save various settings in the tool as the template of this project for later
query, it is necessary to make change in the corresponding sheet.
This sheet is generally visible.
Places where default values are changed:
1. TX Power
Change it in 52~53 lines in “TX RX PART voice”.
2. Technology gain in New Tech
Change it in Tech in V3 table in 26~30 lines in “TX RX PART voice”.
3. Combiner Total Loss
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Change it in 63~67 lines in “V2 configuration”.
4. BTS RX Sensitivity
Change it in 14~24 lines in “TX RX PART voice”.
5. Ant Height
Change it in 2~4 lines in “Feeder ANT Part”.
6. Ant Gain
Change it in 5~9 lines in “Feeder ANT Part”.
7. MS Height
Change it in 10~12 lines in “Feeder ANT Part”.
8. MS gain
Change it in 13~15 lines in “Feeder ANT Part”.
9. Ant Diversity Gain
Change it in 16~18 lines in “Feeder ANT Part”.
10. Sigma
Change it in the third line in “Margins Part1”.
11. Path Loss Exponent
Change it in the fourth line in “Margins Part1”.
12. Rayleigh Fading Margin
Change it in the sixth line in “Margins Part 1”.
13. Interference Margin
Change it in the ninth line in “Margins Part 1”.
14. Body Loss
Change it in the 12th
line in “Margins Part 1”.
15. Propagation Model
Change it in 21~27 lines in (COST model) in “Propagation Model” and 44~79
lines (Standard model).
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3.3.1.4 Link Budget (Complete)
Complete version of link budget result. It mainly reflects the process of calculating
SSmin_req.
This version is relatively suitable for directive bidding, namely, it is used when the
customer has not definitely provided acceptance level.
This sheet is generally visible.
3.3.1.5 Link Budget (Simple)
Simplified version of link budget result does not reflect the process of calculating
SSmin_req.
This version is relatively suitable for use when the customer has definitely put forward
the acceptance level.
This sheet is generally visible.
3.3.1.6 Propagation Model
Setting default parameters in propagation model
Fill in k1~k7 values according o the corrected result of the propagation model. Or
select in “Common Propagation Models and Parameters Setting” the model parameters
relatively suitable for local environment.
This sheet is generally hidden. Opening method: tool > macro > Visual Basic editor,
select in the engineering resource manager the sheet to be queried, and
select-1-xlSheetVisible in Visible option of the attribute window. Select
0-xlSheetHidden if you want to hide it.
3.3.1.7 Prop Model Trans
The method of transformation between COST-HATA model parameters and Standard
model parameters provides an example. If there is transformation demand, it is
necessary to conduct transformation according to this method.
This sheet is generally hidden. Opening method: Tool > macro > Visual Basic editor,
select in the engineering resource manager the sheet to be queried, and
select-1-xlSheetVisible in Visible option of the attribute window. Select
0-xlSheetHidden if you want to hide it.
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3.3.1.8 TX RX PART (Voice)
Places where the default parameters of BTS output power of voice service, BTS
receiver sensitivity (static), and new technology gain are set.
This sheet is generally hidden. Opening method: Tool > macro > Visual Basic editor,
select in the engineering resource manager the sheet to be queried, and
select-1-xlSheetVisible in Visible option of the attribute window. Select
0-xlSheetHidden if you want to hide it.
3.3.1.9 V2 Configuration
Combiner loss of various V2 equipment in various configurations actually includes the
intermediate calculation process of combiner loss of all equipment of V2 and V3.
This sheet is generally hidden. Opening method: tool > macro > Visual Basic editor,
select in the engineering resource manager the sheet to be queried, and
select-1-xlSheetVisible in Visible option of the attribute window. Select
0-xlSheetHidden if you want to hide it.
3.3.1.10 V3 Configuration
Regarding combiner loss of various V3 equipment in various configurations, in fact the
process of V3 calculation is reflected in the in the “intermediate process” in Table “V2
Configuration”.
This sheet is generally hidden. Opening method: tool > macro > Visual Basic editor,
select in the engineering resource manager the sheet to be queried, and
select-1-xlSheetVisible in Visible option of the attribute window. Select
0-xlSheetHidden if you want to hide it.
3.3.1.11 Feeder ANT Part
Places where some parameters are set, such as BTS antenna gain, default BTS antenna
height, MS height, MS antenna gain, 2 way diversity gain, various jumpers, feeder
cable and connector loss, TMA parameter and BTS noise coefficient
This sheet is generally hidden. Opening method: tool > macro > Visual Basic editor,
select in the engineering resource manager the sheet to be queried, and
select-1-xlSheetVisible in Visible option of the attribute window. Select
0-xlSheetHidden if you want to hide it.
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3.3.1.12 Margins Part 1
The settings of the following: various Margins, including calculating shadow fading
margin Sigma, path loss coefficient, fast fading margin, interference margin, body loss
and building penetration loss.
This sheet is generally hidden. Opening method: tool > macro > Visual Basic editor,
select in the engineering resource manager the sheet to be queried, and
select-1-xlSheetVisible in Visible option of the attribute window. Select
0-xlSheetHidden if you want to hide it.
3.3.1.13 Margin Value
Calculation of shadow fading margin and the intermediate process of the conversion
between area coverage probability and edge coverage probability
This sheet is generally hidden. Opening method: tool > macro > Visual Basic editor,
select in the engineering resource manager the sheet to be queried, and
select-1-xlSheetVisible in Visible option of the attribute window. Select
0-xlSheetHidden if you wan to hide it.
3.3.2 Precautions
1. Before use, in “Tool--> Load Macro” firstly tick “Analyze Database” and
“Analyze Database—VBA Function”, otherwise the slow fading margin
calculation tool cannot be used and “#name” error occurs.
2. Every time we change frequency band, we need to re-select Propagation Model,
otherwise propagation model parameters cannot be automatically updated! It is
chiefly due to the fact that initialization is not considered in programming and it
is planned to be updated in subsequent version. The current processing method
is: If we select 900M for the first time and we want to change it into 1800M
template, change frequency band at the left upper corner in Table Input first,
parameters in Propagation Model column do not automatically change with the
above change, it is necessary to manually re-select it. If it was previously
Standard model by default, then select Cost mode, and re-select Standard model.
At this time, read 1800M parameters into the corresponding cell.
3. To select different BTS Type every time, it is necessary to re-select the
corresponding TX Power, otherwise in calculating set-top power, data of the
previous time is used.
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4. When BTS Type (especially when M8206 is switched with other equipment
types) is changed every time, it is necessary to pay attention to ECU and Non
ECU options in Combiner Type. It is chiefly due to the fact that initialization is
not considered in programming and it is planned to be updated in subsequent
version.
For specific M8206 configuration, see forms in V3 Configuration or the content of
Subchapter 2.1 Main Equipment in this article.
For example,
When we select from 8018 to 8206, we firstly select 30w in TX Power. At this time,
options such as ECU Non ECU do not appear in Combiner Type. It is necessary to
select DPCT in New Tech, and at this time, select ECUDPCT in Combiner Type. If at
this time, 8206 does not use DPCT, then re-cancel DPCT option, and select Non ECU
or ECU in Combiner Type. It is necessary to pay attention to 8206 configuration
description.
If you select to return from 8206 to other equipment, select 8018 in BTS Type. For the
case in which the number of carrier frequencies selected in Configuration (TRX/CELL)
is bigger than 4, you can select a combination in Combiner Type at your discretion.
Then select the quantity of real carrier frequencies in Configuration (TRX/CELL)
according to real scenarios. At this time, options in the drop-down menu under
Combiner Type are updated. At this time, make sure to re-select output power in TX
Power.
1. When the customer definitely put forward requirements for Acceptance Level,
execute according to the customer requirements. At this time, it is
recommended to use Link Budget (simple) template for link budget result
output. When the customer has not definitely put forward the requirement,
Acceptance Level should be equal to Minimum Required Level. At this time, it
is recommended to use Link Budget (complete) template for link budget result
output.
2. Calculate Min. required level and design level in the tool according to formula.
Do not change it.
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4 Common Propagation Model & Its Parameter Values
4.1 Okumura-Hata Model
4.1.1 Applicable Scope
4.1.2 Propagation Loss Formula
γ))(lglg55.69.44()(lg82.13lg16.2655.69 dhhahfL bmbb−+−−+=城
Formula description:
The unit of d is km and the unit of f is MHz. 城bLis the median of the basic propagation loss in city urban area.
bh, mh
--the effective height of the base station, mobile station antenna, and its unit is
m.
Calculate the effective height of the base station antenna: Suppose the height from the
base station antenna to the ground is sh, the altitude from the base station ground is gh
,
the height from the mobile station antenna from the ground is mh, and the altitude of
the ground where the mobile station is located is mgh. Then the effective height of the
base station antenna bh= sh
+ gh- mgh
, and the effective height of the mobile station
antenna is mh.
(Note: There are many methods for calculating the effective height of the base station
antenna, such averaging the altitudes of the grounds within 5~10 km around the base
station, and the fitting line of altitudes of the grounds within the base station 5~10 km
around the base station. Different calculation method is related to propagation models
Frequency: 150M~1500M
Hb: 30~200m
Hm: 1~10m
Communication distance:1~35km.
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used, and it is also related to calculation precision requirement.)
Correction factors for mobile station antenna height:
Remote propagation correction factor:
>×+×++
≤= −− 20)
20)(lg1007.11087.114.0(1
2018.034 d
dhf
d
b
γ
4.1.3 Various Correction Factors
(1) Kstreet——street connection factor
General materials only provide the loss correction curve that is parallel to or
perpendicular to the propagation direction. To facilitate calculation, the fitting formula
for any angle is provided below.
Suppose the inclosed angle between the propagation direction and the street is θ, then:
<+−−
≤−−+−−=
1)cos6.7sin9.5(
1cos)lg6
106.7(sin)lg
6
119.5(
d
dddK street
θθ
θθ
In fact street effect generally disappears beyond the scope of 8~10 km, so it is only
considered within 10km.
(2) Kmr——suburban area correction factor
)4.5))28/(lg(2( 2 +−= fK mr
(3) Qo——correction factor for vast area
)94.40lg33.18][lg78.4( 2 +−−= ffQo
(4) Qr——Correction factor for quasi-vast area
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5.50 += QQr
(5) uR——Correction factor for rural area
17.23lg17.9)(lg39.2)28
(lg 22 −+−−= fff
Ru
(6) Kh——Correction factor for hill area
≤≥∆+∆+∆+−−
>≥∆−−∆+∆+−−
<∆
=
1,15)2.7)lg96.6024.07.5(
1,15)2.7lg5.9()lg96.6024.07.5(
150
1
11
hhhh
hhhhh
h
K h
h⊿ ——It is topographic relief height, as shown in the figure below. Calculate from the
mobile station, extend 10 km to the direction of the base station (calculate according to
real distance when it is not up to 10 km), calculate within this range the difference
between 10% of the topographic relief height and 90% of topographic relief height
(suitable for multiple topographic relieves, and the number of topographic relieves >3). ⊿h 10%90%
1h= mgh
- h/8⊿ - minh. minh
is the minimum landform height of the calculation section
h⊿ .
(7) Ksp——Correction factor for general slope landform
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The ground second reflection many occur to slope landform. When the level distance
d2 > d1, in the figure above, the second ground reflection may occur to both positive
slope and negative slope.
The approximate correction factor for slope area is:
mmmsp ddK θθθ 44.0002.0008.02
+−=
The unit of mθ is milli-radian and the unit of d is km.
mθ is the average tilt angle of the heights of relieves within 1 km before and after the
mobile station on the connection line section between the mobile station and the base
station (use least square method)
(8) Kim—— Correction factor for isolated mountain peak.
Here knife-edge diffraction loss is used for calculation. The calculation is more precise
thought it requires larger quantity of calculations, as shown in the figure below:
hph1
r1
r2
Firstly seek the 4 parameters of a single knife-edge, namely, 1r , 2r , ph, and operation
wavelength λ .
Use these 4 parameters to calculate new parameter v :
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)11
(2
21 rrhv p +=
λ
Calculate diffraction loss:
−<=
−>−++−+=
7.00
7.0)1.01)1.0(lg(209.6 2
v
vvvK im
(9) Ks——Correction factor for sea (lake) hybrid path
When propagation path meet water area, the scenarios are considered in two cases, as
shown in the figures below:
The correction factor is defined to be:
+−−
−+−−=
)6.948.0(:)(
)81.068.0/0.7(:)(
2
2
qqdb
dqqqaK ts
Where, q = ds / d (%). sd is the length of all the water body on the section.
The method to select formula (a) or (b):
If on the section between the base station and the mobile station, there is water body
within 200 km near the base station, then:
2/))()(( bKaKK s +=
Otherwise )(bKK s =
(10) S(α )——Correction factor for building density
≤−
≤<++−−
≤<−−
=
120
51)20lg19.0)(lg6.15(
1005)lg2530(
)( 2
a
aaa
aa
as
a——buidling density, % expresses.
The combined use of various amending factors
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Overall path loss:
++
+++=
r
mr
u
sp
im
h
s
streetb
Q
Q
K
R
KK
K
K
aSKLL
0
0
0
)(
4.2 Cost231model
4.2.1 Applicable Scope
4.2.2 Propagation Loss Formula
γ))(lglg55.69.44()(lg82.13lg9.333.46 dhhahfL bmbb−+−−+=城
The unit of d is km and the unit of f is MHz. 城bL is the basic propagation loss median of urban area.
Hb, hm-- base station, effective height of mobile station antenna, with m being unit
Calculation of the effective height of the base station antenna: Suppose the height from
the base station antenna to the ground is sh, the altitude of the base station ground is
gh, the height from the mobile station antenna to the ground is mh
, the altitude of the
ground where the mobile station is located is mgh. Then the effective height of the base
station antenna hb = sh+ gh
- mgh, and the effective height of the mobile station
antenna is mh.
Height correction factor for mobile station antenna:
Frequency: 1.5G~2G
Hb:30~200m
Hm:1~10m
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Correction factor for remote propagation:
>×+×++
≤= −− 20)
20)(lg1007.11087.114.0(1
2018.034 d
dhf
d
b
γ
4.2.3 Various Correction Factors
They are the same as Okumura-Hata model.
4.3 Common Expression of Okumura-Hata and COST231 Model
4.3.1 Applicable Scope
4.3.2 Propagation Loss Formula
Lb=A1+A2Lgf+A3LgHb+(B1+B2LgHb)Lgd-a(hm)
band 850 900 1800 1900
A1 69.55 69.55 46.3 46.3
A2 26.16 26.16 33.9 33.9
A3 -13.82 -13.82 -13.82 -13.82
B1 44.9 44.9 44.9 44.9
B2 -6.55 -6.55 -6.55 -6.55
a(hm) 0.013647703 0.0158818 0.0429745 0.0450878
4.3.3 Common Correction Factors
DU/MU/SU/RU/Road/Open Correction Factors Calculated according to Theoretical
Values.
Frequency: 0.5G~2G
Hb:30~200m
Hm:1~10m
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OFFSET 850 900 1800 1900 Note (Theoretical Value)
DU 0 0 0 0
MU -2 -2 -2 -2
SU -9.7942 -9.943 -11.939 -12.109 Kmr=-(2*(log(f/28))^2+5.4)
RU -19.014 -19.21 -21.915 -22.152 Ru=-(lg(f/28))^2-2.39*(lgf)^2+9.17lgf-23.17
Road -22.763 -23.01 -26.424 -26.727 Qr=Q0+5.5
Open -28.263 -28.51 -31.924 -32.227 Q0=-(4.78*(lgf)^2-18.33*lgf+40.94)
Through experience judgment, the theoretical calculation values of the above
correction factors are a bit exaggerated than the real case. In fact, it is necessary to
adjust the values of the above various parameters according to model correction result.
Sometimes customers provide their recommended correction values, at this time, it is
necessary to determine the values according to specific conditions.
The following table shows the general recommendations.
OFFSET 850 900 1800 1900
DU 0 0 0 0
MU -2 -2 -2 -2
SU -6 -6 -8 -8
RU -15 -15 -17 -17
Road -17 -17 -20 -20
Open -20 -20 -22 -22
4.4 Standard Universal Model (AIRCOM Expression Formula)
4.4.1 Applicable Scope
Frequency: 0.5G~2G
Hb: 30~200m
Hm: 1~10m
4.4.2 Propagation Loss Formula
Lb=k1+k2*lgd+k3*Hms+k4*lgHms+k5lgHeff+k6*lgHeff*Lgd+k7*diffn+ C_loss
Where:
d Distance from the base station to the mobile station (km).
Hms Height of the mobile station above ground (m). This figure may be
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specified either globally or for individual clutter categories.
Heff Effective base station antenna height (m).
Diffn Diffraction loss calculated using either Epstein, Peterson, Deygout or
Bullington Equivalent knife edge methods.
K1,k2 Intercept and Slope. These factors correspond to a constant offset (in
dBm) and a multiplying factor for the log of the distance between the
base station and mobile.
K3 Mobile Antenna Height Factor. Correction factor used to take into
account the effective mobile antenna height.
K4 Okumura-Hata multiplying factor for Hms.
K5 Effective Antenna Height Gain. This is the multiplying factor for the log
of the effective mobile antenna height.
K6 Log(Heff)Log(d). This is the Okumura-Hata type multiplying factor for
log(Heff)log(d).
K7 Diffraction. This is a multiplying factor for diffraction calculations. A
choice of diffraction methods is available.
C_loss Clutter specifications such as heights and separation are also taken into
account in the calculation process.
4.4.3 Propagation Model Parameter Value
Listed below are the corrected propagation models in several places. When local
propagation models are not corrected, see propagation models with similar landforms
and ground objects.
1800M
(1) Indonesia Heji Project-Makassar and Banjiamasin
The collected Makassar propagation model is as follows
MU K1 155.85 Ground object compensation value
K2 44.9 Dense Urban 2.28
K3 -2.55 Dense urban high -0.84
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K5 -13.82 Industrial/commercial -2.468
K6 -6.55
K7 0.8
SU K1 152.3 Ground object compensation value
K2 44.9 Dense urban -0.2775
K3 -2.55 Mean urban -1.394
K5 -13.82 Sparse forest -0.245
K6 -6.55
K7 0.8
RU K1 145.21 Ground object compensation value
K2 44.9 Open land -4.354
K3 -2.55 Residential 0.583
K5 -13.82 River -0.767
K6 -6.55 Sparse forest 1.545
K7 0.8
The collected Banjiamasin propagation model is as follows (landform is quasi-flat):
MU K1 155.91 Ground object compensation value
K2 44.9 Dense urban 0.5166
K3 -2.55 Industrial/commercial -3.62
K4 0 Mean urban -0.031
K5 -13.82
K6 -6.55
K7 1.63
SU K1 150.93 Ground object compensation value
K2 44.9 Agriculture -2.764
K3 -2.55 Open land 3.03
K4 0 Mean urban -0.04
K5 -13.82 Residential 0.156
K6 -6.55 Sparse forest -1.99
K7 0.8 River -0.56
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RU K1 147.69 Ground object compensation value
K2 44.9 Agriculture 1.579
K3 -2.55 Open land 6.337
K4 0 Mean urban -3.838
K5 -13.82 Residential -3.4
K6 -6.55 Sparse forest -0.818
K7 0.8
Pakistan Project-Lahore
DU (old city) K1 160.15
K2 41.28
K3 -2.89
K4 0
K5 -12.7
K6 -2.94
K7 -0.374
DU (new city) K1 158.78327
K2 42.435563
K3 -2.89
K4 0
K5 -12.871
K6 -6.195408
K7 -0.75697
DU(old city) DU(new city)
Clutter Height Sep'n Through
(dB/km)
offset
(dB)
Through
(dB/km)
offset
(dB)
agriculture/plantation 0 0 -3.07 0.00 4.97 -2.67
airport 0 0 0.00 0.00 -6.00 0.00
coast/sea 0 0 0.00 0.00 0.00 0.00
dense_urban 20 2 13.02 0.11 1.08 0.46
forest 5 0 0.00 0.00 0.00 0.00
high_residential 10 1 -8.47 -0.03 -3.47 -0.50
industrial_areas 7 1 -13.44 -5.85 6.64 2.86
low_residential 8 1 0.00 1.34 0.00 4.81
open_areas 0 0 6.97 3.34 10.63 -2.07
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open_in_urban 0 0 -6.60 -1.62 -3.92 -0.11
park 0 0 2.32 0.53 1.30 1.11
semi_open_areas 0 0 3.31 -0.98 7.42 -0.17
urban 10 1 3.63 0.47 0.20 0.20
water 0 0 0.00 0.00 -4.33 0.00
900M
Vietnam Heji Project
Model Type K1 K2 K3 K4 K5 K6 K7
Plain urban area 152.39 43.83 -2.55 0.00 -13.82 -6.55 0.05
Plain suburban
area
149.33 39.25 -2.55 0.00 -13.82 -6.55 0.05
Plain rural area 140.87 38.68 -2.55 0.00 -13.82 -6.55 0.04
Hill urban area 140.88 42.00 -2.55 0.00 -13.82 -6.55 0.10
Hill suburban area 139.73 41.25 -2.55 0.00 -13.82 -6.55 0.09
Hill rural area 137.36 39.50 -2.55 0.00 -13.82 -6.55 0.04
Mountain urban
area
144.93 41.50 -2.55 0.00 -13.82 -6.55 0.06
Mountain
suburban area
141.35 39.25 -2.55 0.00 -13.82 -6.55 0.14
Mountain rural
area
138.93 38.75 -2.55 0.00 -13.82 -6.55 0.02
Highway 139.11 38.24 -2.55 0.00 -13.82 -6.55 0.00
Seaside city 141.82 40.25 -2.55 0.00 -13.82 -6.55 0.04
River-and-lake
city
143.66 40.00 -2.55 0.00 -13.82 -6.55 0.02
Pakistan Project-Lahore
DU (old
city)
K1 149.66275
K2 45.038991
K3 -2.58
K4 0
K5 -14.99366
K6 -5.287317
K7 0.609819
DU (new
city)
K1 147.664
K2 42.870705
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K3 -2.58
K4 0
K5 -14.027928
K6 -4.507256
K7 1.511571
MU K1 147.39482
K2 42.744224
K3 -2.58
K4 0
K5 -14.585
K6 -6.561
K7 0.583088
Clutter Height Sep'n Through
(dB/km)
offset
(dB)
Through
(dB/km)
offset
(dB)
Through
(dB/km)
offset
(dB)
agriculture 0.00 0.00 -13.06 0.00 -0.43 -4.06 -3.40 -3.64
airport 0.00 0.00 0.00 0.00 0.00 0.00 -2.03 0.00
coast/sea 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
dense_urban 20.00 2.00 10.55 0.28 4.71 1.20 6.25 0.89
forest 5.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
high_residential 10.00 1.00 12.16 -1.02 4.13 -0.09 -0.99 0.68
industrial_areas 7.00 1.00 -11.91 -11.07 7.87 5.12 7.57 -0.83
low_residential 8.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00
open_areas 0.00 0.00 -9.45 -0.18 -4.25 0.72 0.06 -5.18
open_in_urban 0.00 0.00 -15.99 -3.54 -19.10 -0.57 -12.61 -1.49
park 0.00 0.00 -17.54 2.10 -15.30 0.02 -0.19 -0.83
semi_open_areas 0.00 0.00 -15.33 0.92 3.94 0.70 -5.31 0.37
urban 10.00 1.00 10.97 0.55 6.93 0.15 6.00 0.25
water 0.00 0.00 4.41 0.00 1.81 0.00 0.84 -3.10
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5 Precautions for Coverage Simulation
The propagation model can only describe the change of the local signal median, which
is expressed in the “slope-intercept” mode. The Best Server in AIRCOM characterizes
the coverage of signal median. In static simulation, it is impossible to express coverage
probability. So the level coverage expressed by Best Server can be seen as the coverage
of signal median when edge coverage probability is 50%.
5.1 Consider Coverage Probability
In the process of the preliminary design, it is usually necessary to consider certain
coverage probability. In this case, how to reflect it in the simulation?
(1) Set the level threshold of Coverage Threshold to be acceptance level.
Measure: When we set PA value (PA value is understood to be set-top transmission
power), we consider shadow fading margin on this basis.
Example: Through the aforesaid presentation, acceptance level can be seen as signal
median level. On this basis, it is necessary to consider certain coverage probability,
such as 95% area coverage probability, so in calculating design level, it is necessary to
consider shadow fading margin (such as 8.7dB) on the basis of acceptance level. When
acceptance level is -70dBm, design level is -61.3dBm.
To reflect coverage probability in coverage simulation, in setting PA, deduct 8.7dB
shadow fading margin on the basis of set-top output power. At this time, on the
coverage simulation map, within the area covered by level value -70dBm, the area
coverage probability is 95%.
If shadow fading margin is not deducted, at this time, within the area covered by level
value -70dBm, the area coverage probability is about 75% (edge coverage probability
is 50%, sigma = 8, n = 3.5).
Set the level threshold of Coverage Threshold to be design level.
Measure: In setting PA value, set according to real set-top output power, it is no longer
necessary to consider shadow fading margin.
Example: It is the same as the above one. If we set Coverage Threshold to be design
GSM Coverage Planning
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level-61.3dBm, within the area covered by -61.3dBm level, the area coverage
probability is 75%. It is equivalent to the fact that in these areas, it is possible to reach
-70dBm coverage with area coverage probability being 95%.
Generally speaking, in order to intuitively express acceptance level, it is recommended
to adopt mode 1.
5.2 Do Not Consider Coverage Probability
In simulation, if it is unnecessary to consider coverage probability, in setting PA value,
it is advisable to set it according to real set-top output power without having to
consider any margins.
Generally speaking, the case in which it is unnecessary to consider coverage
probability mainly appears in model correction, the comparison between real drive test
and simulation. That is to say, in correcting model, it is unnecessary to deduct shadow
fading margin. In using the drive test data of the existing network to detect simulation
result, it is also unnecessary to consider margin.
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6 Recommendations on Project Operation
6.1 Adopt V3.2.1 Method for New Project
For new project or old project that has little relation with previous one, it is
recommended to implement the project according to new link budget method, see Tool
version V3.2.1 and late versions. It is necessary to introduce design level, acceptance
level and minimum required level.
6.2 Adopt V3.1.2 Method for Old Continuous Project
For continuous project which needs to keep consistent with previously submitted result,
it is still necessary to execute the project according to previous method, see Tool
V3.1.2 version.
6.3 Maximum Difference between Two Versions
1. V3.2.1 and later versions have put forward such concepts as design level,
acceptance level and minimum required level, and in downlink budget, on the
basis of acceptance level, it is still necessary to consider shadow fading margin,
fast fading margin, interference margin and body loss. V3.1.2 version and
previous versions have not put forward the above three level concepts, and in
downlink budget, on the basis of acceptance level, it is only necessary to
consider shadow fading margin, and fading margin, interference margin, body
loss and building loss are no longer considered.
2. Propagation model parameters used in V3.2.1 and later versions and those used
in V3.1.2 and previous versions are different.
3. When we use V3.2.1 and later versions, in setting PA value, we execute the
operation according to what is described in Chapter 5. When we use V3.1.2 and
previous versions, in setting PA value, it is necessary to deduct 4 margins
(shadow fading margin, fast fading margin, body loss and interference margin)
on the basis of set-top power. That is, as compared with later versions, on the
basis that both need to consider coverage probability, previous version has to
consider an additional 9dB margin (3dB fast fading margin +3dB body loss +
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3dB interference margin).
4. Seen from the coverage simulation comparison, the coverage after version
upgrade is better than the coverage before version upgrade.