gsm network planning abc - coverage planning v1.0
TRANSCRIPT
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Coverage PlanningCoverage Planning
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Contents
1. Overview of coverage planning
2. Link budget
3. Propagation model
4. Scale estimation. Coverage en!ancing tec!nolog"
#. $!e common coverage issues %&'
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1. What is the purpose of coverage planning?2. What is the work content of coverage
planning?
3. What is the input of coverage planning?
4. What is the output of coverage planning?
1. Overview of coverage planning
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1. (!at is t!e target of coverage planning)
*o t!e*o t!e link budgetlink budget andand radius estimationradius estimation for t!e targetedfor t!e targeted
coverage area so as to get to know t!ecoverage area so as to get to know t!e site scalesite scale andand sitesite
deplo"mentdeplo"ment w!ic! satisf" t!e +P,. -esides if aw!ic! satisf" t!e +P,. -esides if a digital mapdigital map
is available an ad/ustment can be done to t!e sitesis available an ad/ustment can be done to t!e sites
according to t!e results ofaccording to t!e results of coverage simulationcoverage simulation..
*o t!e*o t!e link budgetlink budget andand radius estimationradius estimation for t!e targetedfor t!e targeted
coverage area so as to get to know t!ecoverage area so as to get to know t!e site scalesite scale andand sitesite
deplo"mentdeplo"ment w!ic! satisf" t!e +P,. -esides if aw!ic! satisf" t!e +P,. -esides if a digital mapdigital map
is available an ad/ustment can be done to t!e sitesis available an ad/ustment can be done to t!e sites
according to t!e results ofaccording to t!e results of coverage simulationcoverage simulation..
,t is a must to !ave a t!ree dimensional
digital map 0Planet$ w!ic! covers t!e
w!ole targeted coverage area. *egree of
accurac"
5or urban areas not lower t!an 26m7
5or rural areas not lower t!an 6m.
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2. (!at is t!e work content of coverage planning)
Clarif" t!e
input
Clarif" t!e
input
Site
deplo"ment
Site
deplo"ment
Link budget
Link budget
Propagation
modelcalibration
Propagation
modelcalibration
Coverage
simulation
Coverage
simulation
Scale
estimation
Scale
estimation
Coverag
e
planning
Coverage
planning
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3. (!at is t!e input of coverage planning)
• Which cities and major roads will be covered?
• What are the categories of scenarios according to the radioenvironment?
• What is the coverage range of each scenario?
• Which cities and major roads will be covered?
• What are the categories of scenarios according to the radioenvironment?
• What is the coverage range of each scenario?
The coverage requirements of each scenario
• !overage level
• !overage "robability
The coverage requirements of each scenario
• !overage level
• !overage "robability
• !arry out a test and calibrate the "arameters of the "ro"agation
model#
• $o test is carried out% and the "arameters of the standard
"ro"agation model are ado"ted#
• !arry out a test and calibrate the "arameters of the "ro"agation
model#
• $o test is carried out% and the "arameters of the standard
"ro"agation model are ado"ted#
• The equi"ment ty"es% which will be ado"ted for the bidding%
de"ends on the mar&et strategy#
• The biggest site configuration de"ends on the frequency bands and
the frequency resources#
• Is a 'lanet three(dimensional digital ma" available? The coverage
simulation can not do without the ma"#
• What about the a""lication of the different &inds of coverage
enhancing technologies? ))
• The equi"ment ty"es% which will be ado"ted for the bidding%
de"ends on the mar&et strategy#
• The biggest site configuration de"ends on the frequency bands and
the frequency resources#
• Is a 'lanet three(dimensional digital ma" available? The coverage
simulation can not do without the ma"#
• What about the a""lication of the different &inds of coverage
enhancing technologies? ))
he size and range of
the target coverage
area
he size and range of
the target coverage
area
KPI he coverage KPI
PI he coverage KPI
he parameters of the
propagation model
he parameters of the
propagation model
Others
thers
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4. (!at is t!e output of coverage planning)
Site scale
Site
deployment
Coverage
simulation
he !alanced
!udget of
uplink"downlinkpower
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1. Why is link !udget needed?
2. What is path link !alance?3. #ow can we $udge a link is limited?
4. What is the result if a link is limited?
%. What is link gain and link loss?
&. What is slow fading?
'. What is fast fading?
(. What is coverage pro!a!ility?
). What is margin?
1*. What kind of margin should !e considered for the link !udget?
11. What factors should !e taken into consideration to decide the slow
fading margin which is fre+uently used?
12. What is design signal level and acceptance level?
13. What are the categories of com!iner loss which are fre+uently come
across in link !udget?
14. What factors should !e taken into consideration to decide the power
of the set,top unit of - series e+uipment?1%. What factors should !e taken into consideration to decide the
antenna and feeder loss of - series e+uipment?
1&. What is /0?
1'. #ow to choose the a suita!le type of antenna?
1(. #ow is the uplink"downlink !udget calculated?
1). #ow to avoid the un!alanced link in network planning?
2. Link budget
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2. (!at is link balance)
Strictly speaking link !alance means that the difference ofStrictly speaking link !alance means that the difference of
the path loss of the uplink radio link and that of thethe path loss of the uplink radio link and that of thedownlink radio link is *.downlink radio link is *.
enerally speaking it is considered that there is a roughenerally speaking it is considered that there is a rough
link !alance if the allowed ma5imum path loss differencelink !alance if the allowed ma5imum path loss difference
!etween the uplink and the downlink is no more than!etween the uplink and the downlink is no more than 2d62d6
when the link !udget is calculated.when the link !udget is calculated.
Strictly speaking link !alance means that the difference ofStrictly speaking link !alance means that the difference of
the path loss of the uplink radio link and that of thethe path loss of the uplink radio link and that of thedownlink radio link is *.downlink radio link is *.
enerally speaking it is considered that there is a roughenerally speaking it is considered that there is a rough
link !alance if the allowed ma5imum path loss differencelink !alance if the allowed ma5imum path loss difference
!etween the uplink and the downlink is no more than!etween the uplink and the downlink is no more than 2d62d6
when the link !udget is calculated.when the link !udget is calculated.
7ownlink
coverage
8plink coverage
8plink coverage
9
7ownlink
coverage
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3. 9ow can we /udge a link is limited)
8plink limited
:plink coverage ; *ownlink coverage , t!at is
$!e allowed ma8imum uplink pat! loss ; $!e
allowed ma8imum downlink pat! loss
7ownlink limited
*ownlink coverage ; :plink coverage , t!at is
$!e allowed ma8imum downlink pat! loss ; $!e
allowed ma8imum uplink pat! loss
8plink coverage
7ownlink coverage
he part of invalid
downlink coverage
7ownlink coverage
8plink coverage
$!e part of invalid
uplink coverage
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4. (!at is t!e result if a link is limited)
8plink limited
:n areas with pro!lems the handset has
signals !ut it can not originate a call;
When the su!scri!er moves towards the
!orders of a cell
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5. (!at is link gain and link loss)
ain means that a positive influence is e5erted over the link
and the signals are strengthened.
8nit d6
here are different categories of link gain> 0ntenna gain
diversity gain <
=ain=ain
oss means that a negative influence is e5erted over the link
and the signals are weakened.8nit d6
here are different categories of link loss> @eeder loss
com!iner loss
the loss caused !y the penetration of !uildings or cars
and !ody loss
LossLoss
4*d6m 7evice %*d6m
=ain>6?46>16d-
4*d6m 7evice 32d6m
Loss>46?32>@d-
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6. (!at is slow fading)
(!en t!e signals are transmitted t!e" will be blocked b" t!e buildings and t!e uneven land
forms. ,n t!e areas w!ere t!e signals are blocked t!e s!adow of electromagnetic waves will be
formed. 's a result t!e signal strengt! will be weakened. $!is is called S!adow 5ading a kind
of fading of signals w!ic! is caused b" t!e s!adow effect.
$!e signals go t!roug! a slow and random c!ange wit!in t!e range of doAens of wavelengt!s
so t!e statistical counting obe"s t!e rules of lognormal distribution. $!erefore S!adow 5ading
is also called Slow 5ading.
,n nglis! it is called Slow 5ading ,
or Log?normal 5ading , or S!adow
5ading.
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B. (!at is fast fading)
(!en t!e signals are transmitted t!e" will be reflected and scattered man" times due to t!e surrounding environment 0for
e8ample buildings trees and so on. ,n t!is wa" t!e multi?pat! interference is formed so t!e amplitude and p!ase of a signal ma"
!ave a dramatic c!ange wit! t!e pass of time. $!e overla"ing of t!e multi?pat! signals forms a vector and a possible serious valle"
point of fading w!ic! result in a dramatic fluctuation of t!e intensit" of t!e field and a s!ort?term fading. $!e fast fading is a kind of
deep fading of signals w!ic! is caused b" t!e multi?pat! effect of signal transmission.
$!e statistical counting principles of probabilit" densit" of fast fading obe"s a a"leig! distribution. $!erefore 5ast 5ading is also
called a"leig! 5ading.
,n nglis! it is called 5ast 5ading or a"leig!
5ading.
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@. (!at is coverage probabilit")
Coverage probabilit" refers to !ow large t!e probabilit" is t!at t!e received signal of t!e terminal is larger t!ant!e t!res!old at t!e coverage borders of t!e cell 0or wit!in t!e coverage areas.
Coverage
pro!a!ility
he edge coverage pro!a!ility : he percentage of the cell !orders whosereceived signal is larger than the threshold.
he area coverage pro!a!ility : he percentage of the areas whose receivedsignal is larger than the threshold.
he threshold level of the cell !orders : ,)*d6m
he threshold level of the cell !orders : ,)*d6m
The test is carried out along the covered cell
borders. The edge coverage probability refers to the
percentage of samples, of which the level is at least
- 90dBm.
The test is carried out along the paths of the covered areas of
a cell. The area coverage probability refers to the percentage
of samples, of which the level is at least - 90dBm.
Under the sameconditions, the areacoverage probabilityis larger than theedge coverageprobability. The twocan be mutually
transformedaccording to somerules in math.
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D. (!at is margin)
(!en t!e radio signals are transmitted t!e" will !ave an
attenuation caused b" different kinds factors of t!e radio
environment for e8ample s!adow effect multi?pat! effect
and so on. $!erefore t!e influence caused b" t!ese factors
s!ould be taken into consideration w!en t!e design of radionetwork starts. 't t!e stage of network planning some power
can be reserved to resist t!e possible attenuation. $!e
reserved power is called margin.
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16. (!at kind of margin s!ould be considered for t!e
link budget)??1
*+, is a &ind of interference limited system# The received "ower should not only resist the
noises but also resist the co(channel-adjacent channel interferences which are caused by the
frequency reuse so as to ensure the quality of the signals# The "ower reserved to resist the
interference is called interference margin#
Usually it is .d/#
1
In order to ensure that the site can cover the cell borders with a certain "robability% the site must
reserve some transmission "ower so as to overcome +hadow 0ading# +o the reserved margin
is called +hadow 0ading margin or +low 0ading margin#
3
The multi("ath effect of the transmission of radio signals will result in the fast fading of signals%
so the quality of signals will be affected# 0or *+, system% it resists 0ast 0ading by ma&ing use
of a series of technologies% including interleaving coding% frequency ho""ing% diversity
rece"tion% ada"tive equali1ation% and so on# /esides% at the stage of networ& "lanning% some
design margin should be reserved to resist 0ast 0ading# This is called 0ast 0ading margin#
Usually% it is .d/#
2
Slow @ading marginSlow @ading margin
@ast @ading margin@ast @ading margin
Aamming marginAamming margin
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16. (!at kind of margin s!ould be considered for t!e
link budget)??2
2oss caused by the "enetration of a car refers to the attenuation
which occurs when the radio waves "enetrate the car# It is equal
to the difference value when the median value of the field
strength of the signals outside the car and that inside the car are
com"ared#
Usually% it is 3~4d/#
4/ody loss refers to the &ind of loss which is caused by signal
bloc&ing and absor"tion when the handset is held quite close to
the human body# Usually% for voice service% it is .d/5and for data
service% it is 6d/#
#
2oss caused by the "enetration of a building refers to the
attenuation which occurs when the radio waves "enetrate the
e7terior structures of a building# It is equal to the difference value
when the median value of the field strength outside the building
and that inside the building are com"ared# The value related of
this &ind of loss is closely related to the materials and thic&ness
of the building#
6ody loss6ody loss
oss caused !y the
penetration of a !uilding
oss caused !y the
penetration of a !uilding
oss caused !y the
penetration of a car
oss caused !y the
penetration of a car
!lassification ofdifferent areas
Ty"ical"enetration lossvalue
8ense urban 94 ~ ::
,edium urban 9; ~ :6
+uburban areasand rural areas
96 ~ 9;
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11. (!at factors s!ould be taken into consideration to
decide t!e slow fading margin w!ic! is freEuentl"
used)'rea $"pe
'reaCoverage
Probabilit"
dgeCoverage
Probabilit"
Slow5ading
Fargin 0d-
*ense :rbanSigma>16d-
BG 4G 1
@G #DG
D6G @6G B.B
DG @@G 11.B
Fedium :rbanSigma>@d-
BG 6G 6
@G ##G 3.2
D6G BG .
DG @#G @.B
Suburbanural oad Sigma>#d-
@6G 6G 6
@G #6G 1.#
D6G B1G 3.4
DG @4G .D
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12. (!at is design signal level and acceptance level)
$!e lowest level reEuired SSminHreE
,t refers to t!e lowest level reEuired for making calls in real situations 0outdoorindoorin a car.
On basis of t!e receiver sensitivit" it takes t!e following factors into consideration 5ast 5ading
margin interference margin bod" loss loss caused b" t!e penetration of a building w!ic! is
relevant to a indoor subscriber or loss caused b" t!e penetration of a car w!ic! is relevant to a
subscriber inside a car.
*esign level SSdesign
,n order to ensure a certain probabilit" it is necessar" to consider t!e S!adow 5ading margin on
basis of t!e lowest level reEuired or t!e acceptance level. $!en t!e level value is called design level.
,n ot!er words at t!e network planning stage it is a must to consider t!e possible influence e8erted
b" S!adow 5ading over t!e signal coverage. $!e purpose is to ensure t!e network coverage
probabilit".
'cceptance level SSacceptance
:suall" in t!e bidding documents or t!e contract t!e client will mention t!e *$ coverage +P,
including t!e reEuirements for level value and coverage probabilit" w!ic! *$ s!ould meet.
$!en t!e reEuired level value w!ic! *$ s!ould reac! is called t!e acceptance level b" us.
9owever if t!e client does not !ave an" reEuirements for t!e acceptance level we s!ould
make a suggestion. :suall" it is considered t!at SSacceptance s!ould be eEual to SSminHreE
0SSacceptance > SSminHreE.
1
2
3
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B2 series com!iner loss
13. (!at are t!e categories of combiner loss w!ic! are
freEuentl" come across in link budget)
1
Combiner D66F0d-1@66F0d-
C*: 4.4 4.#
C: 3. 3.
CI .3 .
FC*: 4.4 4.#
C*: 1 1
C: 3. 3.
B3 series com!iner loss
Combiner D66F0d-
1@66F0d-
C*: 4.4 4.#
C: 3. 3.
C*: 1 1
2
S7 series com!iner loss3
5or :62 and :62' t!e COF
loss is 3d- w!en it is S3JS4.
Ot!er radio freEuenc" processing
units do not !ave a combiner
inside.
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1. (!at factors s!ould be taken into consideration to decide t!e
antenna and feeder loss of K$ series eEuipment) $!e $"pical
'ntenna and 5eeder Connection
(it!out
$F'(it!
$F'
5eeder$"pe D66 1@66 :nit
9-:< 99#: 93#3 d/-966m
=-4< .#44 ;#=; d/-966m
;->< :#== >#93 d/-966m
9.-4< :#: .#>= d/-966m
The table here shows the typical KP of !ansen. t is "ust for
your reference. #or a specific pro"ect, the table should be filled
in according to the actual configuration of feeder line KP.
:f the feeder loss is more than
3d6 it is suggested that a
heavier feeder line should !e
used.
$"pe Loss :nit
!onnector 6#6; d/-each
T connector 6#. d/-each
2ightningarrester 6#: d/-each
T,@ insertionloss 6#; d/
$:ncrease the downlink insertion loss of
the tower amplifier
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. (!at factors s!ould be taken into consideration to decide t!e antenna
and feeder loss of K$ series eEuipment) $"pical 'ntenna and
5eeder Connection
:nstallation nearan antenna
1
%%& and BB& is connected
by fiber ;
%%& and antenna is
connected by '()* "umper.
'. )m +* loss for softer "umper
). ) connector loss
Heightof
antennaAmB
Ceight ofDDU on
"latform AmB
Lengthof 7!main
feederlineAmB
2engthof E
"#mperAmB
$onnectorF
lightningarrester
66,A
d/B
9466
,Ad/B
;6 6 ;6 > 3F9 :#4 >#6>
;6 96 >6 > 3F9 :#; .#>3
;6 :6 .6 > 3F9 :#99 :#4
;6 .6 :6 > 3F9 9#=. :#.9
;6 ;6 6 : : 6#.: 6#>.
'. ))m +* softer "umper loss
). ain feeder line loss between %%&
and the antenna
. / connectors loss. ' feeder line lightning arrester loss
he ta!le here is only for reference in practice please
calculate according to specific conditionsD
%%& is installed on the
platform of a tower 1a platform under the
antenna2, or installed at the
roof and it is lower than the
antenna ;
%%& and BB& is connected
by fiber ;
%%& and the antenna is
connected in a normal way.
The length of main feeder
line is the distance between
%%& and the antenna.
he installation
position keeps a
distance from
!oth 668 and
the antenna.
2
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1#. (!at is $F')
$F'M$ower Founted 'mplifier
$ower 'mplifier is t!e s!ort form for $ower Founted 'mplifier. 'ctuall" an amplifier w!ic! !as
low noises and !ig! linearit" 0low noise amplifier is installed at t!e front end of t!e receiving
s"stem of t!e site a place w!ic! is close to t!e receiving antenna. ,t is used to amplif" t!e uplink
signals to improve t!e noise figure of t!e receiving s"stem of t!e site and to improve t!e uplink
coverage capabilit".
EE :: 8sually the FG: designed for the uplink gain is 12d6. 7oes it8sually the FG: designed for the uplink gain is 12d6. 7oes it
follow that 12d6 uplink gain should !e taken into consideration whenfollow that 12d6 uplink gain should !e taken into consideration when
the link !udget is calculated?the link !udget is calculated?
00 :: HoHo. Since /0 is actually a low noise amplifier. In the one hand. Since /0 is actually a low noise amplifier. In the one handthe valid uplink signals are amplified on the other hand different kindsthe valid uplink signals are amplified on the other hand different kinds
of noises and interferences are also amplified. he actual uplink gainof noises and interferences are also amplified. he actual uplink gain
generated !y /0 is usuallygenerated !y /0 is usually 22 ~~ 3d-3d-..
EE :: 8sually the FG: designed for the uplink gain is 12d6. 7oes it8sually the FG: designed for the uplink gain is 12d6. 7oes it
follow that 12d6 uplink gain should !e taken into consideration whenfollow that 12d6 uplink gain should !e taken into consideration when
the link !udget is calculated?the link !udget is calculated?
00 :: HoHo. Since /0 is actually a low noise amplifier. In the one hand. Since /0 is actually a low noise amplifier. In the one handthe valid uplink signals are amplified on the other hand different kindsthe valid uplink signals are amplified on the other hand different kinds
of noises and interferences are also amplified. he actual uplink gainof noises and interferences are also amplified. he actual uplink gain
generated !y /0 is usuallygenerated !y /0 is usually 22 ~~ 3d-3d-..
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1B. 9ow to c!oose t!e a suitable t"pe of
antenna)'rea 'ntenna
!eig!t % m&
'ntennagain % d-i &
9oriAontalbeamwidt!of t!eantenna
Nerticalbeamwidt!of t!eantenna
PolariAationcategories
lectrical downtilt
*ense urban 26 ~ 2 1.J1B # @ ~ 14 *ual?polariAation
6 ~ 16 degreeelectrical downtilt
:rban areas 3 ~ 36 1.J1B # @ ~ 14 *ual?polariAation
2 ~ # degree electricaldowntilt
Suburban areas 3 ~ 46 1BJ1@ # ' D6 B ~ 16 *ual?polariAation
2 ~ 4 degree electricaldowntilt or wit!outelectrical downtilt
ural areas 4 ~ 6 1BJ1@ # ' D6 B ~ 16 *ual?polariAation verticalpolariAation
$!e electrical downtiltis optional.
9ig!wa"s or longand narrowvalle"s
4 ~ #6 1@J22 3 # ~ @ *ual?polariAation verticalpolariAation
$!e electrical downtiltis optional.
,f a single freEuenc" antenna is used b" a co?sited dual?band base station t!e antenna selected for t!e 1@66F base station
s!ould be 1 ~ 2d- !ig!er in antenna gain t!an t!at selected for t!e D66F base station. :suall" t!e antenna of a 1@66F base
station is !ig!er t!an t!at of a D66F base station b" 3 ~ m.
,f a dual?band antenna is selected t!e installation space can be saved. 9owever t!e separate ad/ustment made for t!e two
networks will not be so fle8ible. ,t s!ould be c!ecked w!et!er t!e antenna parameters of t!e two freEuenc" bands can bot!
meet t!e relevant reEuirements.
,n dense urban areas an antenna wit! a lower antenna gain can be c!osen if necessar".
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1@. 9ow is t!e uplinkdownlink budget calculated)
'arameter +ymbol Unit
Transmission "ower of thecarrier frequency
@ d/m
!ombiner loss / d/
Output power of t!e set?top unit of -$S
C>'?- d-m
0eeder line connector loss 8 d/
@ntenna gain of /T+ G d/i
@ntenna gain of ,+ 0 d/i
Deceiver sensitivity of ,+ * d/m
0ast fading margin C d/
Interference margin I d/
/ody loss H d/
2oss caused by the"enetration of a building ora car
d/
+low fading margin 2 d/
$!e minimum levelreEuired 0*L
F>=9,+ d-m
*esign level 0*L I>FL d-m
8ownlin& enhancingtechnology
O d/
$!e ma8imumdownlink pat! lossallowed
P>C?*5?IO d-
'arameter +ymbol Unit
Transmission "ower of ,+ @ d/m
@ntenna gain of ,+ / d/i
@ntenna gain of /T+ ! d/i
8iversity gain 8 d/
0eeder line connector loss G d/
The contribution tosensitivity made by T,@
0 d/
Deceiver sensitivity of /T+ * d/m
0ast fading margin C d/
Interference margin I d/
/ody loss H d/
2oss caused by the"enetration of a building ora car
d/
+low fading margin 2 d/
$!e minimum level
reEuired 0:LF>=9,+ d-
*esign level 0:L I>FL d-
U"lin& enhancingtechnology
O d/
$!e ma8imum uplinkpat! loss allowed
P>'-C*?5?I d-
C!oose t!e ma8imum pat! loss allowed for t!e link w!ic! is limited t!at is Fin 0P uplink P downlinkas t!e ma8imum pat! loss allowed for t!e w!ole linkQ
*ownlink :plink
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1D. 9ow to avoid t!e unbalanced link in network
planning)
he ma5imum uplink path loss allowed J he ma5imum downlink path
loss allowed difference value K 2d6
8plink limited :ncrease the uplink
coverage or decrease the invalid downlink coverage ink !alance
Solution> 0dd /0 adopt 4 antennae to do the diversity reception lower
the transmission power of the carrier fre+uency and so on.
he ma5imum uplink path loss allowed J he ma5imum downlink path
loss allowed difference value K 2d6 8plink limited :ncrease the uplink
coverage or decrease the invalid downlink coverage ink !alance
Solution> 0dd /0 adopt 4 antennae to do the diversity reception lower
the transmission power of the carrier fre+uency and so on.
$!e ma8imum downlink pat! loss allowed ; $!e ma8imum uplink
pat! loss allowed difference value R 2d- *ownlink limited
,ncrease t!e downlink coverage Link balance
Solution> :ncrease the transmission power of the set,top unit of 6Sincrease the num!er of antenna and feeder 7GC technology 77
technology and so on.
$!e ma8imum downlink pat! loss allowed ; $!e ma8imum uplink
pat! loss allowed difference value R 2d- *ownlink limited
,ncrease t!e downlink coverage Link balance
Solution> :ncrease the transmission power of the set,top unit of 6Sincrease the num!er of antenna and feeder 7GC technology 77
technology and so on.
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1. What is propagation model?
2. What are the categories of propagation model?
3. What are the fre+uently,used propagation
models?
4. Why is propagation model cali!ration necessary?
%. #ow to evaluate whether a propagation model is
suita!le or not?
&. #ow to get a propagation model !efore the
cali!ration is done?
3. Propagation model
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1. (!at is propagation model)
0 propagation model is a kind of0 propagation model is a kind of mathematical modelmathematical model whichwhich
descri!es and reflectsdescri!es and reflects the features of the transmissionthe features of the transmission
environment of the radio signals and the rules for theenvironment of the radio signals and the rules for the
changes of the signalschanges of the signals. 0ctually a propagation model. 0ctually a propagation model
representsrepresents a typical modela typical model of the transmission environmentof the transmission environment
which haswhich has some specific featuressome specific features..
0t the planning stage the propagation model can !e used in0t the planning stage the propagation model can !e used in
the following two ways.the following two ways.
0 propagation model is a kind of0 propagation model is a kind of mathematical modelmathematical model whichwhich
descri!es and reflectsdescri!es and reflects the features of the transmissionthe features of the transmission
environment of the radio signals and the rules for theenvironment of the radio signals and the rules for the
changes of the signalschanges of the signals. 0ctually a propagation model. 0ctually a propagation model
representsrepresents a typical modela typical model of the transmission environmentof the transmission environment
which haswhich has some specific featuressome specific features..0t the planning stage the propagation model can !e used in0t the planning stage the propagation model can !e used in
the following two ways.the following two ways.
stimation of t!ecell radius
Simulation
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2. (!at are t!e categories of propagation
model) Fodel Statistical model *eterministic model
Concept $!e propagation modelis based on t!estatistical anal"sis of alarge Euantit" of testingdata.
$!e propagation model isobtained t!roug! t!esimulation of t!e multi?pat!transmission traces of t!eradio waves. $!e simulationis based on t!e geometricalinformation of t!e clutterand t!e buildings w!ic!appear on t!e transmission
pat!.
'mount of calculation Small Large
Computational accurac" 'verage 8cellent
eEuirements for t!e accurac" oft!e digital map
26mJ6m 1mJm
$!e reEuirements for t!e clutter
of t!e digital map
$!e information of t!e
buildings is notincluded.
$!e information of t!e
buildings must be included.
'pplication range R1km ;1km
5reEuentl"?used models O+:F:'?9'$'COS$231:niversal model
NOLC'IO
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$!e freEuentl"?used
propagation models
Okumura?9ata
:niversal model
Nolcano COS$231
3. (!at are t!e freEuentl"?used propagation models)
•6.=J1.=9A( 5or D66F)•Facro cell model•,t is suitable for D66F sites w!eret!e simulation and scale estimationwill be done for a large Euantit" ofsites in a wide range.
•1.=J2=9A 05or1@66F•Facro cell model•,t is suitable for1@66F sites w!eret!e simulation andscale estimation willbe done for a largeEuantit" of sites in awide range.
•6.=J2=9A 05or D66 1@66F•Facro cell model•,t is suitable for t!e sites w!ere t!esimulation and scale estimation will bedone for a large Euantit" of sites in a widerange.•'t present t!is model is adopted b"',COFCIP.
•6.=J2=9A•Ficro cell model•,t is suitable for aspecific area w!ere t!esimulation will be donefor a small Euantit" ofsites.
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4. (!" is propagation model calibration necessar")
$!e radio transmission environment differs for eac! place due to t!e various land forms geograp!ic
features distribution of buildings coverage of vegetation and so on. 5or e8ample cities in plain
areas NS cities in areas wit! !ills cities w!ere t!ere is a dense distribution of !ig! buildings NS
cities w!ere most of t!e buildings !ave 1 ~ 2 store"s cites in desert areas NS cities in areas w!ere
t!ere is a wide coverage of vegetation < < 'ctuall" propagation model calibration is necessar" for
eac! cit". $!e purpose is to get t!e parameters of t!e propagation model w!ic! is consistent wit!
t!e actual situation.,f t!e same set of parameters is applied to ever" scenario it is Euite possible t!at t!e planning
sc!eme differs greatl" from t!e actual situation. 9ere are t!e conseEuences
1. $!e network coverage w!ic! !as been establis!ed is not good enoug! to meet t!e coverage +P,.
2. ,t is a large waste of resources if t!ere are too man" sites. -esides severe interferences ma"
appear if t!ere is a dense distribution of sites.
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. 9ow to evaluate w!et!er a propagation model is
suitable or not)
-efore t!e calibration$!e Fean rror is not 6 t!e standard deviation Std *ev islarge.5igure $!e intersection point of t!e red line and t!e verticala8is is not 6.67 t!e slope of t!e red line is not 6.
9oriAontal ordinate $!e logarit!m of t!e distance betweent!e testing place and t!e base station is represented b"logd.Nertical ordinate $!e Fean rror w!ic! is calculated b"comparing t!e actual level of t!e testing place and t!epredicted level of t!at place is represented b" rror.*ense dots $esting places$!e red line ,t s!ows a kind of tendenc" about w!at t!eFean rror is likel" to be w!en t!e overall actual testingvalues of t!e testing place are compared wit! t!epredicted values.
'fter t!e calibration$!e Fean rror tends to be 6 t!e standard deviation Std*ev;>@d-. $!is means t!e model is Euite consistent wit!t!e actual situation.05or dense urban areas std dev;>16d- is alsoacceptable. 75igure $!e intersection point of t!e red line and t!e verticala8is is 6.67 t!e slope of t!e red line is 6.
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#. 9ow to get a propagation model before t!e calibration
is done)
Conditions
'. The digital map of the city for
which the planning will be done.
). n the propagation model library,
there are a certain amount of
parameter sets related to the
propagation models, which are
reliable and accurate.
. 3 tool used for choosing a model
automatically
:f it is not possi!le to carry out the propagation model test or cali!ration of the
target city due to the pro!lems of resources or time and the like it is accepta!le
to choose a propagation model from the model li!rary !y following some certain
rules. his model can !e regarded as an alternative choice which should !e
similar to the actual radio environment of the target city. #owever there may !e
some differences !etween the alternative choice and the actual situation.
0s to the rules for choosing the model they can !e set up according to the
e5perience of the engineers or !y using some customiLed automatic tool.0ctually this kind of tool will !e applied to the oad /ap of CHG.
isks
t should be noticed that the model,
which is selected by using the tool, can
only be regarded as the most suitablemodel from the e4isting model library.
!owever, it does not mean that it is
completely matched with the actual
environment.
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1. #ow to estimate the coverage radius of a single
site?
2. WhatMs the influence of downtilt over the
coverage?
3. #ow to calculate the site distance at the pre,
planning stage?
4. #ow to estimate the coverage area of a single site?
%. #ow to estimate the scale of coverage?
4. stimation of t!e coverage scale
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1. 9ow to estimate t!e coverage radius of a single site)
!hoose a universal "ro"agation modelPL>k1k2lgdk39mk4lg9mklg9bk#lg9bLgdkBdiffraction clutter LossCere%'2 means the ma7imum "ath loss allowed for the whole lin&% which is calculated in the lin& budget#&9~ &= and !lutter 2oss are the "arameters which are obtained after the "ro"agation modelcalibration# A@s to the estimation of the radius% only &9 ~ &3 will be involved in the calculation#B
Cm is the height of ,+#Cb is the effective height of /T+ antenna#d refers to the distance between the base station and ,+ A&mB#When d of the model above is calculated in a reverse way% the following formula can be obtained#d>16T00PL?+1?+39m?k4lg9m?klg9b0k2k#lg9b9ere d is actuall" t!e estimated coverage radius of t!e base station.
Link budget =et t!e ma8imum pat! loss allowed for a w!ole link t!at is PL.1
Propagation model calibration =et t!e value of eac! parameter of t!e propagation model2
Calculate UdV of t!e propagation model formula in a reverse wa" =et t!e ma8imumcoverageradius of t!e site
3
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2. (!atWs t!e influence of downtilt over t!e coverage)
(!en t!e ma8imum pat! loss allowed is calculated in t!e link budget t!e influence e8erted b" t!edowntilt is not taken into consideration. ,f t!e influence e8erted b" t!e downtilt over t!e coverage is
to be taken into consideration t!e radius s!ould be estimated according to t!e following formula.
*$ *owntilt 0mec!anical downtilt electrical downtilt9 $!e antenna !eig!t of -$S'tan ,nverse tangent trigonometric
functionN- Nertical 3d- beamwidt! of t!eantenna*5 $!e distance to t!e fart!est placew!ic! t!e upward 3d- beamwidt! cancover. ,t is t!e predicted coverage radiusw!en t!e downtilt *$ is taken intoconsideration.*I $!e distance to t!e nearest placew!ic! t!e downward 3d- beamwidt! cancover * $!e distance covered b" t!e main loberig!t a!ead
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3. 9ow to calculate t!e site distance at t!e pre?planning
stage)
$!ree?sector
directional sites Omni sites
The distance between two three(
sector directional sites is 9#;D#D re"resents the radius of the
directional cell#
The distance between two omni
sites is 9#=.D#D re"resents the radius of the
omni cell#
If two(sector directional sites are used for the
coverage of a long and narrow road% the
distance between the sites should be :D#
D re"resents the radius of the directional cell#
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4. 9ow to estimate t!e coverage area of a single site)
' t!ree?sectordirectional site
'n omni site
Cell radius
$!e coveragearea of a single
cell
6.#2 2.#2
$!e coveragearea of a singlesite
1.D2 2.#2
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. 9ow to estimate t!e scale of coverage)
F:
S:
5or e8ample
'ccording to t!e radio environment t!e target cit" 'is divided into two parts t!at is t!e mean urbanarea F: and t!e suburban area S:. $!e two areas
are represented b" two pol"gons separatel".
F: S: Iotes
Cell radius km 6. 1 $!e estimated
radius $!e siAe of t!ecoverage area of asingle cell km2
6.1#2 6.# 6.#2
$!e siAe of t!ecoverage area of asingle site km2
6.4@B 1.D 1.D2
$!e siAe of t!epol"gon km2
4 16$!e siAe of t!epol"gon S
$!e number of-$Ss 0Ium
@ Ium>S01.D2
$!e total number of-$Ss of t!e cit" '
13>Ium0F:Ium0S:
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1. #ow many coverage enhancing technologies are
there?
2. What is !ypass?
3. What is 7GC?
4. What is 77?
%. What is @W7?
&. What is :C?
. Coverage en!ancing tec!nologies
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1. 9ow man" coverage en!ancing tec!nologies are
t!ere)
:plink coverageen!ancing
*ownlinkcoverageen!ancing
Iotes
$F' -"pass
*PC$ and **$ cannot be used at t!esame time.
5(* *PC$
,C **$
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2. (!at is b"pass)
Combiner
*uple8er
LI'
C*:
$X1 $X2 $X
X1
X2
X3
X4
X1
X2
Combiner
*uple8er
LI'
C*:
'I$0X$X
$X1 $X2 $X
X1
X2
X3
X4
X1
X2
$X1 $X2
'I$0X$X
$X XF X* $X XF X*
,f a cell is configured wit! no more t!an 2 carrier freEuencies t!e $X interface of a carrier freEuenc" can
be connected to t!e $X interface of a C*: t!en it can be connected to a *uple8er directl" wit!out t!euse of a combiner.
(!en t!e link budget is calculated onl" 1d- duple8er loss is considered and t!e power of t!e set?top
unit is increased.
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3. (!at is *PC$)
*ual Power Combining $ransmission
*PC$ means t!at two transmitters send t!e same bursts at t!e same time w!ic! are
combined in t!e form of one carrier freEuenc" t!roug! a combiner so as to increase
t!e output power.
5rom a p!"sical perspective *PC$ can !elp to increase t!e power so it is especiall"
suitable for areas w!ic! need a wide coverage.
$!e two signals !ave t!e same p!ase
and amplitude and t!e" are combined
wit!in a carrier freEuenc" module.
$!eoreticall" speaking 3d- downlink
gain can be obtained if one P' is
combined wit! anot!er. 9owever if t!e
internal loss is taken into consideration
t!e actual gain of *PC$ is 2.d-.
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4. (!at is **$)
*ela" *iversit" $ransmission
**$ means t!at two carrier freEuencies send t!e same signals at a slig!tl" different time. $!e
signals are sent out b" different antennae so as to get some timespace diversit" gain. ,n t!is wa"
t!e downlink coverage is en!anced. **$ is suitable for some complicated radio transmission
environment.
't -SC side t!e mainau8iliar" $X can be regarded as one $X and t!e parameters w!ic! t!e
au8iliar" $X is configured wit! are t!e same as t!ose w!ic! t!e main $X is configured wit! . $!eEuantit" of signs inserted between t!em can be configured at OFC.
$!e downlink gain w!ic! can be generated b" **$ is 2J3d-.
D0 '@
D0 '@
'hase adiust
algorithm
'hase adiust
algorithm
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. (!at is 5(*)
5our (a" *iversit" eceiving
5(* means t!at 4 single antennae or 2 dual?polariAed antennae are used to make
a single carrier freEuenc" !ave four?wa" received signals. $!en t!ese signals are
combined as a one?wa" signal t!roug! t!e merging algorit!m so as to en!ance t!e
diversit" gain.
Compared to t!e two wa" diversit" gain 5(* can generate an e8tra 2 ~ 3d- gain
for t!e uplink receiver sensitivit". :nder t!e multi?pat! loss condition t!e dense
urban areas w!ic! !ave a complicated transmission environment can !ave a !ig!er
gain.
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#. (!at is ,C)
,C ,nterference e/ection Combining
,f t!e interferences of t!e diversit" reception signals from two different wa"s are relevant to eac!
ot!er t!e relevance computing will be done for t!e noises of eac! diversit" branc! to c!eck t!e
relevanc" between t!e interferences and to combine t!e signals accordingl". $!e purpose is to
complete t!e interference re/ection and to improve t!e Eualit" of t!e received uplink signals.
(it! ,C C, can get about 3 ~ d- gain in dense urban areas w!ere t!e radio environment is
complicated.
FC Fa8imum atio Combining
,f t!e interferences of t!e diversit" reception signals on two different wa"s are not
relevant to eac! ot!er weig!ting and combining s!ould be done to t!e signals from F
different wa"s.
,f t!e interferences received from different antennae are notrelevant to eac! ot!er t!e performance of ,C is similar tot!at of FC. 9owever if t!e interferences are relevant to eac!ot!er ,C is muc! more stronger t!an FC in terms of t!einterference re/ection abilit".
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1. What is a !lind Lone under a tower?
2. #ow to solve the pro!lem if there is a !lind Loneunder the tower?
3. What is weak coverage?
4. #ow to solve the pro!lem of weak coverage?
%. What is overshooting?
&. #ow to solve the overshooting pro!lem?
'. When is it called that there is not a serving cell?
(. What measures can !e taken to solve the pro!lem
that there is not a serving cell?
#. $!e freEuentl" asked Euestions about
coverage planning %&'
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1. (!at is a blind Aone under a tower)
$ull It refers to the dee" fading "oint between thecentral lobe and the side lobe% or between two sidelobes#
?B6d-m
?D6d-m
?@6d-m
?D6d-m
' blind Aone under a tower refers to a part of t!e user Aone w!ic! needs to be covered
an area w!ic! is covered b" t!e first null or t!e second null under t!e vertical antennaradiation pattern. Compared to an" ot!er area w!ic! is eit!er near or far t!e signalstrengt! of t!e blind Aone under a tower ma" !ave greater attenuation 026 ~ 36d- and aweak coverage area is formed. 's a result t!ere ma" be a large number of subscribercomplaints and t!e +P,s of call drop rate and t!e like ma" be affected.$!e location of t!e blind Aone under a tower is related to t!e antenna radiation patternt!e antenna !eig!t and t!e transmission environment.
@ blind 1oneunder a tower
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y
2. 9ow to solve t!e problem if t!ere is a blind Aone under
t!e tower)
Iull fill $!e s!aped?beam s!ould be used to complete t!e first lower null fill of
t!e side lobe of t!e vertical pattern of t!e antenna so as to reduce t!e deepfading of t!e null.
C!oose a null fill antenna7C!oose an electrical downtilt antenna7'd/ust t!e antenna downtilt appropriatel" so as to avoid t!eblind Aone under a tower in a dense user Aone.
@n antenna with a null fill @n antenna without a null fill
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y
3. (!at is weak coverage)
(eak coverage means t!at t!e signal level is too low to keep agood call Eualit". ,t is usuall" believed t!at t!e coverage will beweak if t!e signal level is lower t!an ?D6d-m. ,f t!e coverage isweak t!ere will be man" problems for e8ample subscribercomplaints !ig! call drop rate and so on.
5or e8ample t!e power of t!e set?top unit of t!e base
station is too small7 t!e site planning is not reasonable7t!e antenna !eig!t is too low according to its original
design7 t!e inclination is too large7 t!ere is some
blocking because of t!e land forms or t!e buildings.
Concept
Causes
@ wea& coverage
area
@ wea& coverage
area
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y
4. 9ow to solve t!e problem of weak coverage)
't t!e network planning stage more attention will be given to
t!e possible weak coverage areas. $!e following factors
s!ould be taken into full consideration $!e site location t!e
antenna t"pe and t!e reasonableness of t!e designed
engineering parameters.
,ncrease t!e power of t!e set?top unit of t!e base station.C!eck t!e decreased power problems caused b" t!e
eEuipment failures.,n t!e weak coverage areas some base stations or repeaters
s!ould be added.
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y
. (!at is overs!ooting)
Overs!ooting means t!at t!e actual coverage range of a
cell e8ceeds t!e range w!ic! !as been designed
before!and and an overlapping area is formed b" t!is celland anot!er cell w!ic! is far from it.
Overs!ooting ma" result in freEuent !andovers an
increase of interferences t!e islanding effects and so on.
9ere are t!e possible causes $!e transmission power
of t!e base station is too large7 t!e antenna lobe is toolarge7 t!e antenna is too !ig!7 t!e inclination is too
small7 t!ere is an uneven land form7 and so on.
Concept
Causes
'
-
C
Cell ' is anovers!ooting
area.
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#. 9ow to solve t!e overs!ooting problem)
One s!ould be cautious w!en t!e site location is selected for a
!ig!land or a mountain slope.
,t s!ould be ensured t!at t!e antenna t"pe and t!e engineeringparameters of t!e antenna s!ould be reasonabl" selected or designed at
t!e network planning stage.$!e coverage area of t!e overs!ooting area s!ould be controlled
t!roug! t!e ad/ustment of engineering parameters and t!e transmission
power of t!e base station.,f it is not possible to control t!e coverage at t!at time it is suggested
t!at some neig!bor cells s!ould be added to t!e overs!ooting cell.
'
-
C
n!ance t!e neig!bor cellrelations between ' and C.
'
-
C
Control t!e coverage area of '.
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$!ere are freEuent cell reselections w!en t!e !andset is at an idle state.
,n t!e cells at t!e borders of L'C t!e location update occurs freEuentl" due to t!e
freEuent cell reselections. 's a result t!ere will be an unnecessar" increase of signalingload or congestion. -esides t!ere will be Uping?pong !andoversV during t!e calls and
t!e voice Eualit" will deteriorate.
$!e transmission rate of t!e data service will be affected.
-ecause of t!e fluctuations of signals t!ere will be more subscriber complaints.
$!ere are interferences C, is not satisfactor" and t!e voice Eualit" deteriorates.
B. (!en is it called t!at t!ere is not a serving cell)
5or 2 or more cells t!e signal strengt! of one cell is Euite close to t!at of anot!er cell it is not
found t!at t!e signal strengt! of an" cell !as a big advantage over ot!er cells. $!e !andset !as
freEuent cell reselections w!en it is at an idle state or t!ere are Uping?pong !andoversV during
t!e calls. $!e problems mentioned !ere are caused b" t!e fact t!at t!ere is not a serving cell.
$!e engineering parameters of
t!e antenna are not designed in a
reasonable wa".$!e transmission power of t!e
carrier freEuencies is too large or
too small.$!e configuration of t!e
parameters is not reasonable NN
5or t!e 3 cells in t!is area t!esignal level of eac! cell is
almost t!e same so t!ere isnot an obvious serving cell.
Concept
,nfluence
Causes
Internal Use Only▲
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@. (!at measures can be taken to solve t!e problem t!at
t!ere is not a serving cell) 'd/ust t!e antenna directional angle or t!e antenna
downtilt so as to ensure t!at t!ere is a serving cell of
t!e coverage area w!ic! !as relativel" strong and
stable signals.
'd/ust t!e transmission power of t!e carrier
freEuencies of t!e relevant cells so as to ensure t!at
t!ere is a serving cell of t!e coverage area w!ic! !asrelativel" strong and stable signals.
(!en t!e serving cell of t!e area is made clear it is
suggested t!at t!e cell reselection parameters s!ould
be ad/usted so as to ensure t!at t!e subscribers can
reside in t!e serving cell as long as possible. ,n t!is
wa" it is possible to relieve t!e freEuent cellreselections.
(!en t!e serving cell of t!e area is made clear it is
suggested t!at t!e !andover parameters of t!e cells s!ouldbe ad/usted so as to reduce or eliminate t!e Uping?pong
!andoversV during t!e calls.
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