new52237367-3g-case-analiz.pdf

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3 Tools and Links

3.2 Monitor and decoder

The Monitor is a good tool to trace in the Nodes constantly but it has to he handled with care. Itallows the user to troubleshoot but it needs a target loadmodule on the Node. This has to be

loaded in the Node. The risk is if you run too many traces on the Node the load will increase andthis will reduce the capacity in the Node.

You will find the web page here. Where you can download a Monitor and decoder package.

There is another tool that send 'te log read' on the selected boards and merge the log files

together that it looks like a continuous flow.The link is missing!

Fest decoder

Fest is a tool that read a log file and if it encounters a he"string# $%&' '(N) and %&'

*(+(I,( on te logs and almost e-erything in an illuminator log it adds a readable description

of the data

/ere you can download a Fest -ersion for Wilma based on 0erl 1.2.34 small documentation is a-ailable here

Decoder

The instruction how to install and the main Web 0age is located here

The latest -ersion of the decoder can be downloaded from this page

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3.3 MoShellThis tool allows it read and modify the M56s in the Node. This is -ery powerful tool for

troubleshooting but don6t use it to etensi-e for modification in a li-e system. The Tool to use for

changes is *4N5' $5'' *+7 or (M4' from the Nodes.4 direct link to the creator page from Mo'hell.

8ink to the Tiny Tool web page

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA2.html#TOP

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA2.html#CHAPTER3

http://rn01.epa.ericsson.se/eanzmagn/other-tools/index.htm

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/files/fest_WIL_RBS_INC3.zip

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/files/fest_documentation.fm

http://wrn.ericsson.se/~eramnak/

http://wrn.ericsson.se/~eramnak/decoder/

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA203.html#top%23top


http://rn01.epa.ericsson.se/eanzmagn/moshell/index.htm

http://internal.ericsson.se/page/hub_radionetwork/products/plm/plmwran/toolsandserv.html


http://rn01.epa.ericsson.se/eanzmagn/other-tools/index.htm

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/files/fest_WIL_RBS_INC3.zip

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/files/fest_documentation.fm

http://wrn.ericsson.se/~eramnak/

http://wrn.ericsson.se/~eramnak/decoder/



http://rn01.epa.ericsson.se/eanzmagn/moshell/index.htm





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3.4 Shello

'hello is a command"line interface to a +ello node. It adds con-enience to interacti-e use7 can beused in other scripts to send commands to a node7 and is easily etensible by you.

'hello is a front"end to +ello6s command line interface7 telnet7 ftp7 and M5"%rowser7 with an

interface into &ni.

S <--------telnet------> C

H <--------ssh---------> E

E <---------ftp--------> L

L <-----mo-browser-----> L

L O

O <----pipe-+ |

V

!"#

8ink to the 'hello web page.

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3.5 Consistency Check Tool (CCT)

The ++T has been designed as a 9M4+*59 using ,isual %asic and (cel. The ++T compares

the management ob:ects and attributes from the Winnow database against the Mo'hell outputetracted from the nodes.

Winnow database has been recently modified. This means that the procedure to obtain the right

winnow file for the macro is different than before.

For 0;.< the field 9*ecommended ,alues9 does not ha-e anything7 so instead of selecting

9*ecommended ,alues9 you should select 9New )efault9.

The fields to select in order to generate the winnow file are= 9M5+ Name9 90arameter Name9

9)efault ,alue9 9New )efault9. 5nce you sa-e it into a file and open it with (cel it is necessary

to rename the following columns

9moc>name9 to 9mo>name9

9p>default>-alue9 to 9default -alue9

9new>default9 to 9recomm>-alue9



http://eed.ericsson.se/services/eed-x-s/o/soe/cello/shello/index.html



ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA203.html#CHAPTER3.6%23CHAPTER3.6




http://eed.ericsson.se/services/eed-x-s/o/soe/cello/shello/index.html







'a-e the file as (cel and you will be ready to run ++T.

)ownload the tool here


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3. !inno" Data#ase

The Winnow database contains information connected to Managed 5b:ect $M5 classes7

parameters and actions included in the radio access network for ;? mobile systems. It is based onthe Managed 5b:ect Models $M5M6s7 which defines which M5 classes7 parameters and actions

that should be included. Winnow also contains other information like -arious classifications7

document references and parameter ?&I information.

8ink to the Winnow database

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3.$ CelloMate (CM)

+elloMate is an application de-eloped for a more efficient use of the telnet interface against a

+ello node. The idea behind the program is to integrate the windows interface with a Telnetsession7 a message decoder7 a 8() monitor and some other useful features. 8ink to the

+elloMate web page

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3.% Co&parin' Tool

This tool is able to find the parameter changes between an old and a new dump from the same

node7 and missing neighbour relations7 including eternal relations between two *N+s.

. Co&parin' t"o d&ps*

%efore using the tool you need to ha-e two Mo'hell dumps from the same node fetched atdifferent dates7 and an (cel file containing the operator parameters.

Insert the path of the old Mo'hell dump in 9Mo'hell 3 File 0ath=9

Insert the path of the new Mo'hell dump in 9Mo'hell @ File 0ath=9

http://cdmweb.ericsson.se/WEBLINK/ViewDocs?DocumentName=EAB%2FRGN-03%3A0205&Revision=A




http://winnow.wrn.ki.sw.ericsson.se/




http://internal.ericsson.se/page/hub_iberia/unit/global_services/cs_iberia/tools/cellomate/index.html





http://cdmweb.ericsson.se/WEBLINK/ViewDocs?DocumentName=EAB%2FRGN-03%3A0205&Revision=A













Insert the path of the 5perator 0arameters file in order to know which parameters to

compare.

+lick on 98oad dumps95nce the dumps are loaded click on 9+ompare dumps9

The result is two (cel files with three worksheets each.

The first file contains the comparison of all parameters in the dumps=

+co&pare+*

contains the parameters which changed their -alues7 showing the old $9)ump 3 -alue9and the new $9)ump @ -alue9 -alues.

+created&os+*

contains the M5#s which are present in the new dump $second dump but not in the old

dump $first )umpand their parameters.

+deleted&os+*

contains the M5#s which are present in the old dump $first dump but not in the newdump $second dump and their parameters.

The second file contains only the comparison of the 5perator 0arameters=

+,-co&pare+*



contains the parameters7 which changed their -alues7 showing the old $9)ump 3 -alue9

and the new $9)ump @ -alue9 -alues.

+,-created+*

contains the M5#s which are present in the new dump $second dump but not in the olddump $first dump and their parameters.

+,-deleted+*

contains the M5#s which are present in the old dump $first dump but not in the new

dump $second dump and their parameters

2. Findin' &issin' nei'h#or relations.

Insert the path of one *N+ dump in 9Mo'hell 3 File 0ath=9

Insert the path of another *N+ dump in 9Mo'hell @ File 0ath=9

+lick on 98oad dumps9

5nce the dumps are loaded click on 9+heck Neighbours9The tool will check the internal relations in both *N+s and the eternal relations between

them.

The result is an (cel file showing the missing relations.

)ownload the tool here

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3. /ode Stats 0nalyser (/S0)

This new Tools will be a-ailable from [email protected] on and comes deli-ery with *4N5'. The Node'tatus 4nalyser $N'4 pro-ides the user with the means to from one single application get a

collected and comprehensi-e -iew of the status of an *%'. N'4 displays the status for *N+

related information7 Iub link7 *%' node and *%' hardware. The information presented is a

snapshot of the status when N'4 was launched. 4lso links to other applications and +0I isa-ailable.

4 part of this is the +abinet -iewer and you can find a presentation how it will look like in +)M.

/ere is the link to the presentation in +)M


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ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/files/Comparing%20Tool%202.1.zip



http://cdmweb.ericsson.se:7034/TeamCenter/controller/ViewDocs?DocumentName=2%2F15941-10%2FFCP1034405



ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/files/Comparing%20Tool%202.1.zip



http://cdmweb.ericsson.se:7034/TeamCenter/controller/ViewDocs?DocumentName=2%2F15941-10%2FFCP1034405





3.1 0MS

The 4IM' $4ir Interface Mobile 'imulation tool enables the tester to perform /ando-er procedures $'oftAsofter and I*4T /ando-er without any other additional eBuipment. 4 handling

of 4IM' makes also possible to use predefined scripts and seBuences in order to force the &(

andAor system for predefined purposes.

4 ;? 8aCy ?uide is a-ailable here

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4 Tro#le shootin'

adio /et"ork -eror&ance Monitorin' and ,pti&iation6ideline

*e-ision history

e7 Date Description

4 @<<@"<3"33 First release

% @<<@"3<"@1 4dd 0@ new functions into the document

*estructure the document to di-ide it into three parts7 i.e. performance monitoring7 W+)M4

optimisation issues and trouble shooting.

+ @<<D"<3";< &pdate to 0;. The trouble shooting part is

reorganiCed to easier find lists of fault cases andsolutions. 4ll information not related to the

trouble shooting part is remo-ed. *4N5'

parameter names are changed to system parameter names to straighter forward comply

with winnow and other parameter information

sources.

ntrodction

,7er7ie"


ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/files/AIMS%20Lazy%20Guide.doc



http://cdmweb.ericsson.se/WEBLINK/ViewDocs?DocumentName=24%2F1551-HSD10102%2F1&Latest=true


http://cdmweb.ericsson.se/WEBLINK/ViewDocs?DocumentName=24%2F1551-HSD10102%2F1&Revision=B

http://cdmweb.ericsson.se/WEBLINK/ViewDocs?DocumentName=24%2F1551-HSD10102%2F1&Revision=PC1


ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/files/AIMS%20Lazy%20Guide.doc









The scope of this document is to pro-ide ideas how to trouble shoot the 0;.< W+)M4 radio

network. It does not gi-e a full picture of all possible reasons for abnormal beha-iour7 but mighthelp to track problems for further analysis. It is a trouble shooting guideline to sol-e isolated

problems7 and not a guide how to optimise the whole radio network as such.

It should be noted that=

• The intention of the document is not to pro-ide a guideline for how to treat parameters to

achie-e an optimum performance of the functions. 0lease refer to +0I documentation fordetails.

• The parameter names in the document are the parameter names in the system7 not

necessarily the same as the names in the *4N5' ?&I. If con-ersion to *4N5' ?&Inames is needed7 please refer to the +0I documentation.

Denotations

In this guideline7 parameters7 obser-able and counters are presented in bold7 in italic and in boldE italic7 respecti-ely. For eample7

-ri&aryC-C8po"er 0arameter for power of the primary pilotchannel. 5bser-e that the parameter names in

this document are the *4N5' parameter

names7 which are usually not eactly thesame as they are in the *N+

CPICH_Ec/No 5bser-able for the recei-ed energy per chip

di-ided by the power density in the band

pmTransmittedCarrierPower +ounter for the a-erage downlink transmittedcarrier power

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4. Call setp pro#le&s

4.. ,7er7ie"

The call setup procedure can roughly be di-ided into D steps=

• *andom access procedure• **+ connection setup

**+ connection (stablishment pro-ides the ability to establish an **+ connection7 which is a

logical connection7 between the &( and &T*4N at 8;. 4 radio connection comprises the

http://cpi.al.sw.ericsson.se/alex




ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA2.html#CHAPTER4.1








connection between a &( and &T*4N including all the resources7 i.e.7 837 8@ and 8;. The &(

makes the initial access to &T*4N and reBuests for a **+ connection. *adio resources areallocated and a **+ connection is established between &( and &T*4N.

• 'ignalling connection establishment

'ignalling connection establishment pro-ides the ability to establish a signalling connection

between the &( and a core network7 i.e. one signalling connection towards the +' core network

and one towards the 0' core network. (stablishment of the first signalling connection is initiated by the &( as soon as the **+ connection is successfully established. 4n Iu control plane

connection is then established between &T*4N and the core network. When a signalling

connection is already established towards one core network7 the &( can initiate establishment ofa second signalling connection to the other core network at any time. 4n Iu control plane

connection is then established between &T*4N and that other core network.

• *4% establishment

*4% establishment pro-ides the ability to establish of a user plane data stream within &T*4N.

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4..2 ando& access procedre pro#le&s

4..2. ,7er7ie"

The random access procedure consists of the following steps=

3. The &( transmits a preamble.

@. If the *%' properly detects the preamble it sends an 4cknowledgement Indicator $4I on

the 4cBuisition Indication +hannel $4I+/.;. If the &( does not recei-e an 4I7 it transmits a new preamble with higher T power.

D. If the &( recei-es the 4I7 the 0*4+/ message part is sent.







Figure D.3 Illustration of the random access procedure

In order to be acknowledged7 the recei-ed preamble power must be $";2 E

<.1prea&#leThreshold d% o-er the interference. The prea&#leThreshold parameter is an

(ricsson only parameter with default -alue ;D7 i.e. "3Gd%. The correct parameter settings for*4+/ power ramping should be set like below=

$3

'o that the maimum possible preamble power is large enough for 4I+/ acknowledgement.

4ccording to &8 open loop power control7 the initial preamble power is=

$@

The estimated uplink path loss is obtained by $-ri&aryCpich-o"erA3< H CPICH_RSCP . Thus7



$;

If the estimated uplink path loss is same as the actual uplink path loss and the measured uplink

total interference is similar to the actual uplink total interference7 eBuation ; will become=

$D

4..2.2 Falt Cases

Falt Case

*%' does not send out the 4I+/ acknowledgement to the &( and the transmission power of the

&( has not reached its maimum allowed T power

The reason for this fault is improper parameter setting for power ramping on *4+/. The eBuality

in eBuation D is broken.

Falt Case 2

*%' does not send out the 4I+/ acknowledgement to the &( e-en though the transmission

power of the &( has reached its maimum allowed T power

The reason for this fault is because of imbalance between 0*4+/ and pilot channel co-erage.

The power ramping is restricted by the maimum allowed &( T power.



Figure D.@ (ample of 0*4+/ and pilot co-erage imbalance

Falt Case 3

The *%' sends out an 4I+/ acknowledgement to the &( but it does not recei-e it.

The reason for this fault is because of insufficient 4I+/ power. The power of the 4I+/ is notautomatically modified with the -ariation of the network load. For that reason7 the engineer has to

carefully plan enough 4I+/ power to fulfil the assumed downlink load. If a mistake is done

during the power calculation or the real load of the downlink carrier is larger than the assumedle-el7 4I+/ might not co-er the whole cell.

Back to 4..2.3 Falt Case 3

Falt Case 4

*%' sends out the 4I+/ acknowledgement to the &( and the &( recei-es it and then sends out

the *4+/ message. %ut it is ne-er recei-ed in the *%'.

The reason for this fault is because of insufficient power for *4+/ message.

When the preamble is acknowledged7 it implies that=

$1

/owe-er7 in order to recei-e the *4+/ message7 the &( T power should be=

$2

Therefore7 the correct parameter settings should be=

$

If the eBuality of the eBuation is broken7 the power for *4+/ message might be insufficient.

Falt Case 5

Incorrect power measurements due to TM4. For operators using TM47 they ha-e to inputfollowing information into &T*4N in order to obtain accurate &8 and )8 power measurements7

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204.html#4.1.2.3FC3%234.1.2.3FC3




e.g. uplink feeder attenuation7 downlink feeder attenuation7 uplink TM4 gain7 downlink TM4

insertion loss7 etc. 5therwise7 all power measurements in &T*4N will be messed up.

If the parameters are set incorrectly7 the estimated uplink path loss or measured total uplinkinterference might be wrong. 4s a result7 the eBuality of the eBuation D is broken.

4..2.3 Soltions

Falt Case

The engineer should ad:ust the parameters for *4+/ power ramping so that the

-rea&#leetransMa9 po"eroset-1E Constant:aleCprach is greater than or eBual to H

3Gd%.

It should be noted that these parameters are cell parameters.

Falt Case 2

The reasons of causing the J0*4+/ and pilot co-erage imbalanceK are similar to these for

Juplink and pilot co-erage imbalanceK. They are=

• 8arge power in the pilot channel. 0lease read chapter D.L.; Fault +ase 3@.

• /igh restriction to the &( T power. 0lease read chapter D.L.; Fault +ase 3;.• 8ow restriction in &8 congestion control. 0lease read chapter D.L.; Fault +ase 3D.

Falt Case 3

0lease read chapter D.3.@.@ Fault +ase ;.

Falt Case 4

The engineer should check if the parameter settings fulfil the eBuality of the eBuation .

It should be noted that the prea&#leThreshold is an (ricsson only parameter with default -alue H3Gd%. It implies the operators are only allowed to ad:ust the Constant:aleCprach and

-o"er,set-p& to sol-e this problem. Note= They are per cell parameters.

Falt Case 5

/ow to treat this problem is described in 90ower reference 0oint )efinition9.

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ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204-5.html#4.8.3FC12







http://cdmweb.ericsson.se/WEBLINK/ViewDocs?DocumentName=131%2F1551-HSD10102%2F1&Revision=A










4..3 C Connection Setp pro#le&s

4..3. ,7er7ie"

The fault cases are di-ided into L main fault cases. From these L cases there are references to sub

fault cases when these eist.

4..3.2 Falt Cases

The L main fault cases are=

Falt Case

The &( does not send out J**+ connection reBuestK message to &T*4N.

The reason for this fault might be a failure in the **+ connection release. If a **+ connection

had been established7 it is impossible to establish more than one **+ connection unless the

pre-ious **+ connection is released.

Falt Case 2

The &( recei-es J**+ connection setupK message and starts the transmission. %ut the target*%' does not send out J*adio link restore indicatorK to the *N+.

This implies that the &( and &T*4N are trying to synchroniCe each other but the uplink is not

synchroniCed.

Falt Case 3

The &( recei-es an J**+ connection setupK message and starts the transmission. %ut the &(does not send out J**+ connection setup completeK message to &T*4N.

This implies that the &( and &T*4N are trying to synchroniCe to each other but the downlink is

not synchroniCed.

Falt Case 4

The &( recei-es an J**+ connection setupK message and starts the transmission. 4fter a while7the &( sends out J**+ connection setup completeK to &T*4N but the **+ connection

establishment fails.

This might be because &T*4N does not recei-e the J**+ connection setup completeK message.

Therefore7 a possible reason is poor Buality in uplink.

Falt Case 5





The &( recei-es J**+ connection re:ectK message with cause -alue JcongestionK.

4t each reBuest for establishment of a new **+ connection7 it is checked that this is accepted by

the processor load super-ision function in the *N+. In case of re:ect from the load super-isionfunction7 the '"*+/ will send J**+ connection re:ectK to the &( and the procedure ends. The

cause -alue of the message is JcongestionK.

Falt Case

The &( recei-es J**+ connection re:ectK with cause -alue JunspecifiedK.

The reason for this fault might be a failure in the dedicated radio link setup.

Falt Case $

The &( repeatedly sends J**+ connection reBuestK messages but the number of transmissions is

less than /311 E 3 times.

Normally7 the &( will repeatedly transmit J**+ connection reBuestK for at least /311 E 3 times

if it does not recei-e any J**+ connection setupK message. Therefore7 if the number oftransmissions is less than /311 E 3 times7 it implies that the e-ent Jno suitable cellK happens

during **+ connection establishment.

Falt Case %

The &( does not recei-e any message from &T*4N.

The J**+ connection re:ectK or J**+ connection setupK message is transmitted -ia '"++0+/$F4+/. If the &( does not recei-e any message from &T*4N7 a possible reason is because of

'"++0+/ $F4+/ failure.

There is no power control on the common channels. For that reason7 the engineer has to carefully

plan enough F4+/ power to fulfil the assumed downlink load. If mistake is done during the power calculation or the real load of the downlink carrier is larger than the assumed le-el7 the

F4+/ might not co-er the whole cell.

4..3.3 Soltions

Falt Case

No solution is pro-ided.

Falt Case 2



This fault case co-er that the uplink is not synchroniCed. This problem is further di-ided into @

sub"fault cases

.The trans&ission po"er o the ;< reaches &a9i&& allo"ed 7ale

5ne possible reason is uplink and pilot co-erage imbalance. 0lease read chapter D.L.; Fault +ase3@"32.

4nother possible reason is improper cell re"selection offset setting=

If the cell reselection offset7 i.e. =,setsn (C-C8 SC-) or =,set2sn (C-C8 <c>/o) ofthe camped cell is gi-en a too large positi-e -alue7 the new idle mode co-erage may be larger

than the maimum allowed &8 )0+/ co-erage7 i.e. the &( can not reach the *%' when it is at

the cell border. 0lease see Figure D.; Therefore7 synchroniCation in uplink dedicated radio link

during connection setup fails.

Figure D.; +o-erage -ariations after changing the cell re"selection offset

'olution

The =,setsn (C-C8 SC-) or =,set2sn (C-C8 <c>/o)) should be decreased to makesure there is &8 )0+/ co-erage.

Note= +hanging cell re"selection offset may cause different borders in idle and dedicated modes.

To sol-e this problem7 the same -alue should be gi-en to the indi-idual offset ndi7idal,set

and cell offset =,setsn (C-C8 SC-) or =,set2sn (C-C8 <c>/o).

2. The trans&ission po"er o the ;< does not reach the &a9i&& allo"ed 7ale.

+ase 3= If the ;lnitSirTar'et8i'h(Lo") or the c-, is set too low7 the initial &8 )0++/

power becomes too low for the establishment.

%ackground=







The initial uplink )0++/ power is calculated in the &( according to=

$L

Note= There are @ parameters for &8 Initial 'I* Target= ;lnitSirTar'et8i'h $for 'fO32 and

;lnitSirTar'etLo" $for 'f PO;@.

+ase @= If the operator employs TM4 and inputs wrong parameters for the antenna configuration7

the estimated downlink path loss or the measured total uplink interference will be wrong. 4s a

result7 the calculation for the initial &8 )0++/ power becomes incorrect.

'olution 3=

The engineer should ad:ust the ;lnitSirTar'et8i'h(Lo") and C-, to suitable -alues.

Note=

• ;lnitSirTar'et8i'h(Lo") is a *% connection parameter. +hanging it will affect all

connections with the same *% type in a *N+.• C-, is an *N+ parameter. +hanging it will affect the whole *N+.

'olution @=

/ow to correctly handle reference point issues is described in 90ower reference 0oint

)efinition9.

Falt Case 3

)ownlink dedicated radio link synchroniCation failure can depend on many things. 1 possiblereasons and solutions are listed here=

• intended DL D-C8 and pilot co7era'e i&#alance

The downlink co-erage of )0+/ in some particular *% types may not be planned to balance with the pilot co-erage. Therefore7 synchroniCation in downlink dedicated radiolink during connection setup will fail.

Soltion

It should be considered if it is necessary to pro-ide full co-erage for that )8 )0+/ type

or not.







If a change of co-erage is needed the combination of the parameters &a9-"rMa9 7

inter-"rMa97 &in-"rMa97 &ini&&ate7 nterate and Ma9ate shall be tuned.For further information7 see the +apacity Management +0I.

• /ot intended DL D-C8 and pilot co7era'e i&#alance

0lease read chapter D.3<.@ Fault +ase 3.

• &proper cell re?selection oset settin'

If the cell re"selection offset7 i.e. =,setsn (C-C8 SC-) or =,set2sn (C-C8

<c>/o) of the camped cell is gi-en a too large positi-e -alue7 the new idle mode co-eragemay be larger than the maimum allowed )8 )0+/ co-erage. I.e. the &(s close to the

cell border does not ha-e )+/ co-erage to set up a call. 0lease see Figure D.;. Therefore7

synchroniCation in downlink dedicated radio link during connection setup fails.

Soltion

The =,setsn (C-C8 SC-) or =,set2sn (C-C8 <c>/o) should be decreased.

Note= +hanging cell re"selection offset may cause different borders in idle and dedicated

modes. To sol-e this problem7 the same -alue should be gi-en to the indi-idual offset

ndi7idal,set and cell offset =,setsn (C-C8 SC-) or =,set2sn (C-C8

<c>/o)

• Too lo" initial do"nlink S tar'et

If the initial 'I* target of the downlink channel Dlinitsirtar'et is set too low7synchroniCation in downlink dedicated radio link during connection setup will fail.

Soltion

Increase the Dlinitsirtar'et.

Note= The Dlinitsirtar'et is a parameter per *% connection. +hanging it will affect all

connections in same *% in a *N+.

• &proper #acko constant settin'

The C#acko is a constant to back off the 5pen 8oop 0ower +ontrol estimate to a

conser-ati-e starting point. /igher C#acko means the *%' will transmit higher initialdownlink )0+/ power. 5n the other hand7 if it is set too low7 synchroniCation in

downlink dedicated radio link during connection setup will fail because of not enough

initial downlink )0+/ power.

Soltion


ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1Pa104-6.html#4.10.2FC1

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204.html#Figure%204.3%23Figure%204.3







Increase the C#acko to allow higher initial downlink )0+/ power.

Note= The C#acko is an *N+ parameter. +hanging it will affect the whole *N+.

Falt Case 4

0lease read chapter D.3<.@ Fault +ases 3L"@@.

Falt Case 5

The engineer should re"dimension the capacity of the eisting *N+. If needed7 more processors

are added.

Falt Case

)edicated radio link setup failure. This fault case can be di-ided into D sub"fault cases.

* The /C does not send @adio link setp reAest /B0- &essa'e to the tar'et BS.

The reason for this problem can be cell blocking due to admission control. 0lease read [email protected].

2* The /C sends @adio link setp reAest to and recei7es @adio link setp response

ro& the tar'et BS respecti7ely.

The reason for this is because of failure in the 448@ establishment.

3* The /C recei7es @adio link setp ailre /B0- &essa'e ro& the tar'et BS.

The reason for this fault is because of lack of *%' hardware. 0lease read chapters D.D.; and D.D.D.

4* The /C does not recei7e any &essa'e ater sendin' the @adio link setp reAest.

The reason for this fault is because of no response from the target *%'.

The engineer should check if=

3. The target *%' is blocked.

@. The Transport network has problem.

Back to 4..5.3 Falt Case $

Falt Case $

0lease read chapter D.;..



ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204-1.html#CHAPTER4.2.4















Note=

3. ;?00 @1.;;3",.;..< specifies that the number of the retransmissions of the J**+

connection reBuestK should be /311 if the &( does not recei-e the J**+ connectionsetupK message.

@. The number of retransmissions can be greater than /311 if the &( has recei-ed J**+connection re:ectK message or re"select another cell. In this case7 the &( counter ,;<<has been reset.

Falt Case %

0lease read chapter D.L.; Fault +ase 3.

Back to Top

4..4 Si'nallin' Connection <sta#lish&ent Failres

4..4. ,7er7ie"

The fault cases listed here are reduced to when JInitial direct transferK and J)ownlink directtransferK are not recei-ed in &T*4N and the &( respecti-ely.

4..4.2 Falt Cases

Falt Case

The &( sends out JInitial direct transferK message to &T*4N7 but &T*4N does not recei-e it.

Falt Case 2

&T*4N sends out J)ownlink direct transferK message to the &(7 but the &( does not recei-e it.

4..4.3 Soltions

Falt Case

The reason for this fault might be poor Buality in uplink. 0lease refer to D.3<.@ Fault +ases 3L"@@.

Falt Case 2

The reason for this fault might be poor Buality in downlink. 0lease refer to D.3<.@ Fault +ases @;"@2.

Back to Top



















4..5 0B and B <sta#lish&ent or elease pro#le&s

4..5. ,7er7ie"

This section contains both *4% and *% establishment problems. Fault case 3 concerns *4%

establishment failure7 Fault cases @"2 concerns *adio %earer setup problems and fault cases "33concerns *adio %earer release problems.

4..5.2 Falt Cases

Falt Case

The +ore network sends out J*4% assignment reBuestK to the '"*N+ but the '"*N+ replies

J*4% assignment responseK with cause J*4%s failed to setup or modifyK to the core network.

Falt Case 2

&T*4N does not send J*adio bearer setupK message to the &(.

The cell does not ha-e enough radio or hardware resources for the new radio bearer. Therefore


Falt Case 3

&T*4N sends out J*adio bearer setupK message to the &( but the &( does not recei-e it.

The reason for this fault might be poor Buality in downlink.

Falt Case 4

The &( recei-es J*adio bearer setupK but it does not send out J*adio bearer setup completeK to

&T*4N.

0ossible reasons for this fault might be some non"radio issues=

• 448@ establishment between *N+

• 4nd the core network is not 5Q.• The &( has resource problems.

If it is a failure to establish on *4+/AF4+/ this fault might be a cell update procedure failure.

'ee chapter D.;.G.







Falt Case 5

The &( sends out J*adio bearer setup completeK message to &T*4N but &T*4N does not

recei-e it.

The reason for this fault might be poor Buality in uplink.

Falt Case

&T*4N recei-es the J*adio bearer setup completeK message but the radio bearer establishment

still fails.

Falt Case $

&T*4N does not send J*adio bearer releaseK message to the &( on F4+/. The reason for thisfault might be dedicated radio link setup failure.

Falt Case %

&T*4N sends J*adio bearer releaseK message to the &( on F4+/ but the &( does not recei-e

it.

If &T*4N sends J*adio bearer releaseK message to the &( on F4+/ but the &( does notrecei-e it7 a possible reason is because of '"++0+/ $F4+/ failure.

+ommon channels are not under power control. For that reason7 the engineer has to carefully plan

enough '"++0+/ power to fulfill the assumed downlink load. If mistake is done during the

power calculation or the real load of the downlink carrier is larger than the assumed le-el7 '"++0+/ might not co-er the whole cell.

Falt Case

The &( recei-es a J*adio bearer releaseK message from the *N+. 5n the other hand7 the *%'

does not send out J*adio link restore indicatorK to the *N+.

The reason for this fault might be uplink dedicated radio link synchroniCation failure.

Falt Case 1

The &( recei-es J*adio bearer releaseK message7 but it does not send out J*adio bearer release

completeK message on )+/ to &T*4N.

This fault might be because of downlink dedicated radio link synchroniCation failure.

Falt Case



The &( sends a J*adio bearer release completeK message on )+/ to &T*4N7 but &T*4N does

not recei-e it.


4..5.3 Soltions

Falt Case

No direct solutions are pro-ided for this fault case7 but ; eamples that can help in furtheranalysis.

3. The *4% mapping is unsuccessful.

There is a counter in performance statistics to record this issue. It is called pmNoInvalidRabEstablishAttempts.

@. The &( does not ha-e enough capability to setup the *4% type.

;. Iu bearer establishment failure

This reason is only for +' *4% establishment. There are two possible reasons to cause failure in

Iu bearer establishment=

• 448@ connection setup is unsuccessful.

• The Iu"c initialisation procedure is unsuccessful.

Falt Case 2

0lease read chapters D.D.;7 D.D.D and [email protected].

Falt Case 3

0lease read chapter D.3<.@ Fault +ases @;"@2.

Falt Case 4

If there is a cell update procedure problem7 please read chapter D.;.G.

Falt Case 5


Falt Case




















These problems might occur during release of resources. The resources could be=

• 448@

• /ardware• *adio access bearer

Falt Case $

0lease read chapter D.3.;.; Fault +ase 2.

Falt Case %


Falt Case

0lease read chapter D.L.; Fault +ase 3@"32.

Falt Case 1

No solution is pro-ided.

Falt Case


Back to Top

4 Tro#le shootin'

adio /et"ork -eror&ance Monitorin' and ,pti&iation

6ideline

*e-ision history

e7 Date Description

4 @<<@"<3"33 First release

% @<<@"3<"@1 4dd 0@ new functions into the document

*estructure the document to di-ide it into three

parts7 i.e. performance monitoring7 W+)M4optimisation issues and trouble shooting.

+ @<<D"<3";< &pdate to 0;. The trouble shooting part is



























reorganiCed to easier find lists of fault cases and

solutions. 4ll information not related to the

trouble shooting part is remo-ed. *4N5' parameter names are changed to system

parameter names to straighter forward comply

with winnow and other parameter informationsources.

ntrodction

,7er7ie"

The scope of this document is to pro-ide ideas how to trouble shoot the 0;.< W+)M4 radionetwork. It does not gi-e a full picture of all possible reasons for abnormal beha-iour7 but might

help to track problems for further analysis. It is a trouble shooting guideline to sol-e isolated

problems7 and not a guide how to optimise the whole radio network as such.


• The intention of the document is not to pro-ide a guideline for how to treat parameters toachie-e an optimum performance of the functions. 0lease refer to +0I documentation for

details.

• The parameter names in the document are the parameter names in the system7 notnecessarily the same as the names in the *4N5' ?&I. If con-ersion to *4N5' ?&I

names is needed7 please refer to the +0I documentation.

Denotations

In this guideline7 parameters7 obser-able and counters are presented in bold7 in italic and in boldE italic7 respecti-ely. For eample7

-ri&aryC-C8po"er 0arameter for power of the primary pilot

channel. 5bser-e that the parameter names in

this document are the *4N5' parameternames7 which are usually not eactly the

same as they are in the *N+

CPICH_Ec/No 5bser-able for the recei-ed energy per chipdi-ided by the power density in the band

pmTransmittedCarrierPower +ounter for the a-erage downlink transmittedcarrier power

Back to Top









4. Call setp pro#le&s

4.. ,7er7ie"

The call setup procedure can roughly be di-ided into D steps=

• *andom access procedure

• **+ connection setup

**+ connection (stablishment pro-ides the ability to establish an **+ connection7 which is alogical connection7 between the &( and &T*4N at 8;. 4 radio connection comprises the

connection between a &( and &T*4N including all the resources7 i.e.7 837 8@ and 8;. The &(

makes the initial access to &T*4N and reBuests for a **+ connection. *adio resources are

allocated and a **+ connection is established between &( and &T*4N.

• 'ignalling connection establishment

'ignalling connection establishment pro-ides the ability to establish a signalling connection

between the &( and a core network7 i.e. one signalling connection towards the +' core network

and one towards the 0' core network. (stablishment of the first signalling connection is initiated by the &( as soon as the **+ connection is successfully established. 4n Iu control plane

connection is then established between &T*4N and the core network. When a signalling

connection is already established towards one core network7 the &( can initiate establishment ofa second signalling connection to the other core network at any time. 4n Iu control plane

connection is then established between &T*4N and that other core network.

• *4% establishment

*4% establishment pro-ides the ability to establish of a user plane data stream within &T*4N.

Back to Top

4..2 ando& access procedre pro#le&s

4..2. ,7er7ie"

The random access procedure consists of the following steps=

3. The &( transmits a preamble.

@. If the *%' properly detects the preamble it sends an 4cknowledgement Indicator $4I on

the 4cBuisition Indication +hannel $4I+/.;. If the &( does not recei-e an 4I7 it transmits a new preamble with higher T power.











D. If the &( recei-es the 4I7 the 0*4+/ message part is sent.

Figure D.3 Illustration of the random access procedure

In order to be acknowledged7 the recei-ed preamble power must be $";2 E<.1prea&#leThreshold d% o-er the interference. The prea&#leThreshold parameter is an(ricsson only parameter with default -alue ;D7 i.e. "3Gd%. The correct parameter settings for

*4+/ power ramping should be set like below=

$3

'o that the maimum possible preamble power is large enough for 4I+/ acknowledgement.

4ccording to &8 open loop power control7 the initial preamble power is=

$@



The estimated uplink path loss is obtained by $-ri&aryCpich-o"erA3< H CPICH_RSCP . Thus7

$;

If the estimated uplink path loss is same as the actual uplink path loss and the measured uplink

total interference is similar to the actual uplink total interference7 eBuation ; will become=

$D

4..2.2 Falt Cases

Falt Case

*%' does not send out the 4I+/ acknowledgement to the &( and the transmission power of the

&( has not reached its maimum allowed T power

The reason for this fault is improper parameter setting for power ramping on *4+/. The eBuality

in eBuation D is broken.

Falt Case 2

*%' does not send out the 4I+/ acknowledgement to the &( e-en though the transmission

power of the &( has reached its maimum allowed T power

The reason for this fault is because of imbalance between 0*4+/ and pilot channel co-erage.

The power ramping is restricted by the maimum allowed &( T power.



Figure D.@ (ample of 0*4+/ and pilot co-erage imbalance

Falt Case 3

The *%' sends out an 4I+/ acknowledgement to the &( but it does not recei-e it.

The reason for this fault is because of insufficient 4I+/ power. The power of the 4I+/ is notautomatically modified with the -ariation of the network load. For that reason7 the engineer has tocarefully plan enough 4I+/ power to fulfil the assumed downlink load. If a mistake is done

during the power calculation or the real load of the downlink carrier is larger than the assumed

le-el7 4I+/ might not co-er the whole cell.

Back to 4..2.3 Falt Case 3

Falt Case 4

*%' sends out the 4I+/ acknowledgement to the &( and the &( recei-es it and then sends out

the *4+/ message. %ut it is ne-er recei-ed in the *%'.

The reason for this fault is because of insufficient power for *4+/ message.

When the preamble is acknowledged7 it implies that=

$1

/owe-er7 in order to recei-e the *4+/ message7 the &( T power should be=

$2

Therefore7 the correct parameter settings should be=





$

If the eBuality of the eBuation is broken7 the power for *4+/ message might be insufficient.

Falt Case 5

Incorrect power measurements due to TM4. For operators using TM47 they ha-e to inputfollowing information into &T*4N in order to obtain accurate &8 and )8 power measurements7

e.g. uplink feeder attenuation7 downlink feeder attenuation7 uplink TM4 gain7 downlink TM4

insertion loss7 etc. 5therwise7 all power measurements in &T*4N will be messed up.

If the parameters are set incorrectly7 the estimated uplink path loss or measured total uplinkinterference might be wrong. 4s a result7 the eBuality of the eBuation D is broken.

4..2.3 Soltions

Falt Case

The engineer should ad:ust the parameters for *4+/ power ramping so that the

-rea&#leetransMa9 po"eroset-1E Constant:aleCprach is greater than or eBual to H

3Gd%.

It should be noted that these parameters are cell parameters.

Falt Case 2

The reasons of causing the J0*4+/ and pilot co-erage imbalanceK are similar to these for

Juplink and pilot co-erage imbalanceK. They are=

• 8arge power in the pilot channel. 0lease read chapter D.L.; Fault +ase 3@.• /igh restriction to the &( T power. 0lease read chapter D.L.; Fault +ase 3;.

• 8ow restriction in &8 congestion control. 0lease read chapter D.L.; Fault +ase 3D.

Falt Case 3

0lease read chapter D.3.@.@ Fault +ase ;.

Falt Case 4

The engineer should check if the parameter settings fulfil the eBuality of the eBuation .














It should be noted that the prea&#leThreshold is an (ricsson only parameter with default -alue

H3Gd%. It implies the operators are only allowed to ad:ust the Constant:aleCprach and

-o"er,set-p& to sol-e this problem. Note= They are per cell parameters.

Falt Case 5

/ow to treat this problem is described in 90ower reference 0oint )efinition9.

Back to Top

4..3 C Connection Setp pro#le&s

4..3. ,7er7ie"

The fault cases are di-ided into L main fault cases. From these L cases there are references to subfault cases when these eist.

4..3.2 Falt Cases

The L main fault cases are=

Falt Case

The &( does not send out J**+ connection reBuestK message to &T*4N.

The reason for this fault might be a failure in the **+ connection release. If a **+ connectionhad been established7 it is impossible to establish more than one **+ connection unless the

pre-ious **+ connection is released.

Falt Case 2

The &( recei-es J**+ connection setupK message and starts the transmission. %ut the target

*%' does not send out J*adio link restore indicatorK to the *N+.

This implies that the &( and &T*4N are trying to synchroniCe each other but the uplink is not

synchroniCed.

Falt Case 3

The &( recei-es an J**+ connection setupK message and starts the transmission. %ut the &(

does not send out J**+ connection setup completeK message to &T*4N.

This implies that the &( and &T*4N are trying to synchroniCe to each other but the downlink is

not synchroniCed.









Falt Case 4

The &( recei-es an J**+ connection setupK message and starts the transmission. 4fter a while7

the &( sends out J**+ connection setup completeK to &T*4N but the **+ connectionestablishment fails.

This might be because &T*4N does not recei-e the J**+ connection setup completeK message.

Therefore7 a possible reason is poor Buality in uplink.

Falt Case 5

The &( recei-es J**+ connection re:ectK message with cause -alue JcongestionK.

4t each reBuest for establishment of a new **+ connection7 it is checked that this is accepted by

the processor load super-ision function in the *N+. In case of re:ect from the load super-ision

function7 the '"*+/ will send J**+ connection re:ectK to the &( and the procedure ends. The

cause -alue of the message is JcongestionK.

Falt Case

The &( recei-es J**+ connection re:ectK with cause -alue JunspecifiedK.

The reason for this fault might be a failure in the dedicated radio link setup.

Falt Case $

The &( repeatedly sends J**+ connection reBuestK messages but the number of transmissions is

less than /311 E 3 times.

Normally7 the &( will repeatedly transmit J**+ connection reBuestK for at least /311 E 3 times

if it does not recei-e any J**+ connection setupK message. Therefore7 if the number of

transmissions is less than /311 E 3 times7 it implies that the e-ent Jno suitable cellK happens

during **+ connection establishment.

Falt Case %

The &( does not recei-e any message from &T*4N.

The J**+ connection re:ectK or J**+ connection setupK message is transmitted -ia '"++0+/$F4+/. If the &( does not recei-e any message from &T*4N7 a possible reason is because of

'"++0+/ $F4+/ failure.

There is no power control on the common channels. For that reason7 the engineer has to carefully

plan enough F4+/ power to fulfil the assumed downlink load. If mistake is done during the

power calculation or the real load of the downlink carrier is larger than the assumed le-el7 the




Note= +hanging cell re"selection offset may cause different borders in idle and dedicated modes.

To sol-e this problem7 the same -alue should be gi-en to the indi-idual offset ndi7idal,set

and cell offset =,setsn (C-C8 SC-) or =,set2sn (C-C8 <c>/o).

2. The trans&ission po"er o the ;< does not reach the &a9i&& allo"ed 7ale.

+ase 3= If the ;lnitSirTar'et8i'h(Lo") or the c-, is set too low7 the initial &8 )0++/

power becomes too low for the establishment.

%ackground=

The initial uplink )0++/ power is calculated in the &( according to=

$L

Note= There are @ parameters for &8 Initial 'I* Target= ;lnitSirTar'et8i'h $for 'fO32 and

;lnitSirTar'etLo" $for 'f PO;@.

+ase @= If the operator employs TM4 and inputs wrong parameters for the antenna configuration7the estimated downlink path loss or the measured total uplink interference will be wrong. 4s a

result7 the calculation for the initial &8 )0++/ power becomes incorrect.

'olution 3=

The engineer should ad:ust the ;lnitSirTar'et8i'h(Lo") and C-, to suitable -alues.

Note=

• ;lnitSirTar'et8i'h(Lo") is a *% connection parameter. +hanging it will affect allconnections with the same *% type in a *N+.

• C-, is an *N+ parameter. +hanging it will affect the whole *N+.

'olution @=

/ow to correctly handle reference point issues is described in 90ower reference 0oint)efinition9.

Falt Case 3

)ownlink dedicated radio link synchroniCation failure can depend on many things. 1 possible

reasons and solutions are listed here=







• intended DL D-C8 and pilot co7era'e i&#alance

The downlink co-erage of )0+/ in some particular *% types may not be planned to

balance with the pilot co-erage. Therefore7 synchroniCation in downlink dedicated radiolink during connection setup will fail.

Soltion

It should be considered if it is necessary to pro-ide full co-erage for that )8 )0+/ type

or not.

If a change of co-erage is needed the combination of the parameters &a9-"rMa9 7

inter-"rMa97 &in-"rMa97 &ini&&ate7 nterate and Ma9ate shall be tuned.

For further information7 see the +apacity Management +0I.

• /ot intended DL D-C8 and pilot co7era'e i&#alance


• &proper cell re?selection oset settin'

If the cell re"selection offset7 i.e. =,setsn (C-C8 SC-) or =,set2sn (C-C8

<c>/o) of the camped cell is gi-en a too large positi-e -alue7 the new idle mode co-erage

may be larger than the maimum allowed )8 )0+/ co-erage. I.e. the &(s close to the

cell border does not ha-e )+/ co-erage to set up a call. 0lease see Figure D.;. Therefore7synchroniCation in downlink dedicated radio link during connection setup fails.

Soltion

The =,setsn (C-C8 SC-) or =,set2sn (C-C8 <c>/o) should be decreased.

Note= +hanging cell re"selection offset may cause different borders in idle and dedicated

modes. To sol-e this problem7 the same -alue should be gi-en to the indi-idual offset

ndi7idal,set and cell offset =,setsn (C-C8 SC-) or =,set2sn (C-C8

<c>/o)

• Too lo" initial do"nlink S tar'et

If the initial 'I* target of the downlink channel Dlinitsirtar'et is set too low7synchroniCation in downlink dedicated radio link during connection setup will fail.

Soltion

Increase the Dlinitsirtar'et.










Note= The Dlinitsirtar'et is a parameter per *% connection. +hanging it will affect all

connections in same *% in a *N+.

• &proper #acko constant settin'

The C#acko is a constant to back off the 5pen 8oop 0ower +ontrol estimate to aconser-ati-e starting point. /igher C#acko means the *%' will transmit higher initial

downlink )0+/ power. 5n the other hand7 if it is set too low7 synchroniCation in

downlink dedicated radio link during connection setup will fail because of not enoughinitial downlink )0+/ power.

Soltion

Increase the C#acko to allow higher initial downlink )0+/ power.

Note= The C#acko is an *N+ parameter. +hanging it will affect the whole *N+.

Falt Case 4


Falt Case 5

The engineer should re"dimension the capacity of the eisting *N+. If needed7 more processors

are added.

Falt Case

)edicated radio link setup failure. This fault case can be di-ided into D sub"fault cases.

* The /C does not send @adio link setp reAest /B0- &essa'e to the tar'et BS.

The reason for this problem can be cell blocking due to admission control. 0lease read [email protected].

2* The /C sends @adio link setp reAest to and recei7es @adio link setp response

ro& the tar'et BS respecti7ely.

The reason for this is because of failure in the 448@ establishment.

3* The /C recei7es @adio link setp ailre /B0- &essa'e ro& the tar'et BS.

The reason for this fault is because of lack of *%' hardware. 0lease read chapters D.D.; and D.D.D.

4* The /C does not recei7e any &essa'e ater sendin' the @adio link setp reAest.














The reason for this fault is because of no response from the target *%'.

The engineer should check if=

3. The target *%' is blocked.

@. The Transport network has problem.

Back to 4..5.3 Falt Case $

Falt Case $

0lease read chapter D.;..

Note=

3. ;?00 @1.;;3",.;..< specifies that the number of the retransmissions of the J**+

connection reBuestK should be /311 if the &( does not recei-e the J**+ connectionsetupK message.

@. The number of retransmissions can be greater than /311 if the &( has recei-ed J**+

connection re:ectK message or re"select another cell. In this case7 the &( counter ,;<<has been reset.

Falt Case %


Back to Top

4..4 Si'nallin' Connection <sta#lish&ent Failres

4..4. ,7er7ie"

The fault cases listed here are reduced to when JInitial direct transferK and J)ownlink directtransferK are not recei-ed in &T*4N and the &( respecti-ely.

4..4.2 Falt Cases

Falt Case

The &( sends out JInitial direct transferK message to &T*4N7 but &T*4N does not recei-e it.

Falt Case 2

&T*4N sends out J)ownlink direct transferK message to the &(7 but the &( does not recei-e it.














4..4.3 Soltions

Falt Case

The reason for this fault might be poor Buality in uplink. 0lease refer to D.3<.@ Fault +ases 3L"@@.

Falt Case 2

The reason for this fault might be poor Buality in downlink. 0lease refer to D.3<.@ Fault +ases @;"

@2.

Back to Top

4..5 0B and B <sta#lish&ent or elease pro#le&s

4..5. ,7er7ie"

This section contains both *4% and *% establishment problems. Fault case 3 concerns *4%

establishment failure7 Fault cases @"2 concerns *adio %earer setup problems and fault cases "33

concerns *adio %earer release problems.

4..5.2 Falt Cases

Falt Case

The +ore network sends out J*4% assignment reBuestK to the '"*N+ but the '"*N+ replies

J*4% assignment responseK with cause J*4%s failed to setup or modifyK to the core network.

Falt Case 2


The cell does not ha-e enough radio or hardware resources for the new radio bearer. Therefore&T*4N does not send J*adio bearer setupK message to the &(.

Falt Case 3

&T*4N sends out J*adio bearer setupK message to the &( but the &( does not recei-e it.

The reason for this fault might be poor Buality in downlink.

Falt Case 4














The &( recei-es J*adio bearer setupK but it does not send out J*adio bearer setup completeK to

&T*4N.

0ossible reasons for this fault might be some non"radio issues=

•

448@ establishment between *N+• 4nd the core network is not 5Q.

• The &( has resource problems.

If it is a failure to establish on *4+/AF4+/ this fault might be a cell update procedure failure.'ee chapter D.;.G.

Falt Case 5

The &( sends out J*adio bearer setup completeK message to &T*4N but &T*4N does not

recei-e it.


Falt Case

&T*4N recei-es the J*adio bearer setup completeK message but the radio bearer establishment

still fails.

Falt Case $

&T*4N does not send J*adio bearer releaseK message to the &( on F4+/. The reason for this

fault might be dedicated radio link setup failure.

Falt Case %

&T*4N sends J*adio bearer releaseK message to the &( on F4+/ but the &( does not recei-e

it.

If &T*4N sends J*adio bearer releaseK message to the &( on F4+/ but the &( does not

recei-e it7 a possible reason is because of '"++0+/ $F4+/ failure.

+ommon channels are not under power control. For that reason7 the engineer has to carefully plan

enough '"++0+/ power to fulfill the assumed downlink load. If mistake is done during the power calculation or the real load of the downlink carrier is larger than the assumed le-el7 '"

++0+/ might not co-er the whole cell.

Falt Case

The &( recei-es a J*adio bearer releaseK message from the *N+. 5n the other hand7 the *%'

does not send out J*adio link restore indicatorK to the *N+.





This section is di-ided into 1 areas. They are listed below together with counters that indicate

there might be a problem.

• )ownlink congestionThis is indicated by a high -alue of the counter pmSumOfTimesMeasOlDl

•

&plink congestionThis is indicated by a high -alue of the counter pmSumOfTimesMeasOlUl • /igh blocking rate due to admission control

This is indicated by a high -alue of the counter pmNoReDeniedAdm

• 'er-ice differentiation H high blocking rate to non"guaranteed user the following

symptoms can be obser-ed=

Firstly7 many admission denies are found in a cell. This is indicated by the counter

pmNoReDeniedAdm.

'econdly7 the non"guaranteed access is blocked7 i.e.

3. 4-erage )8 4'(7 i.e. is close to or larger than the

0seDl0d& " BeMar'in0seDl or

@. 4-erage &8 4'(7 i.e. is close to or larger than the

0se;l0d& H BeMar'in0se;l or

;. is close to or larger than the

-"r0d& " BeMar'inDl-"r or

D. 4-erage )8 code allocation usage is close to or larger than the Dlcodead& "BeMar'inDlCode.

• /igh +ongestion and 4dmission re:ect in an isolated cell

3. Many congestion e-ents are found in a cell7 but not in its neighbours. I.e.

pmSumOfTimesMeasOlDl and pmSumOfTimesMeasOlUl are -ery high.@. Many admission denies are found in a cell7 but not in its neighbours. This is

indicated by the counter pmNoReDeniedAdm.

Back to Top

4.2.2 Do"nlink con'estion

4.2.2. Falt Cases

Falt Case

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/igh downlink T power

Falt Case 2

)8 T power fluctuation

There are two thresholds for )8 congestion control. They are=

• -"r0d& E -"r0d&,set E -"r,set $threshold D in Figure D.D• -"r0d& E -"r0d&,set $threshold @ in Figure D.D

If the a-erage )8 T power ratio7 7 is lower thanthreshold @ and far away from threshold D7 we can determine that the )8 T power has high

fluctuation. 0lease see Figure D.D.

Figure D.D. (ample of )8 power fluctuation

Falt Case 3

The downlink congestion thresholds might be set too low7 resulting in a waste of capacity.

Falt Case 4

For the operators using TM47 they ha-e to input the following information into &T*4N in order

to obtain accurate &8 and )8 power measurements7 e.g. uplink feeder attenuation7 downlink

feeder attenuation7 uplink TM4 gain7 downlink TM4 insertion loss7 etc. 5therwise7 all powermeasurements and algorithms in &T*4N will be messed up.



If the sum of the attenuations of all parameters for downlink antenna path is less than the sum of

the real -alues7 the downlink power measurement will be o-er"estimated. For instance7

Table D.3. 4n eample to illustrate the incorrect downlink power measurement

4 Total downlink power transmission at *%' port D;d%m

% *eal TM4 insertion loss "3<d%

+ *eal downlink feeder loss ";d%

) O

4E%E+

Total downlink power transmission at

power reference point

;<d%m

( 0arameter for TM4 insertion loss "1d%

F 0arameter for downlink feeder loss "3d%

? O

4E(EF

+alculated total downlink power

transmission at power reference point

;d%m

/ O ?") 5-er"estimated difference d%

4.2.2.2 Soltions

Falt Case

0lease read chapter D.3<.@ Fault cases D"L

Falt Case 2

'olution 3=

The engineer can ad:ust the parameters in the )8 congestion control to o-ercome this fluctuation problem. For eample7

• Increase -"r,set

• 8onger -"r8yst $+ongestion Measurement /ysteresis Time

It should be noted that the sum of the congestion thresholds is still lower than 3<<R.

'olution @=

The engineer should check if the nter-"rMa9 or Min-"rMa9 for a radio connection is set

too high. Too high downlink maimum allowed T code power might cause )8 T power

fluctuation when the user is using high )8 power at the cell border.

Falt Case 3






The engineer should check if the downlink congestion thresholds match to the planned downlink

capacity.

Falt Case 4

0lease refer to 90ower reference 0oint )efinition9 to sol-e this problem.

Back to Top

4.2.3 ;plink con'estion

4.2.3. Falt Cases

Falt Case

/igh uplink *''I

Falt Case 2

&8 interference fluctuation.

There are two thresholds for &8 congestion control. They are=

• Threshold 3= Con' E ,set

• Threshold @= Con'

If the a-erage &8 *''I7 which can be obtained from +T*7 is lower than threshold @ and far away

from threshold 37 we can determine the &8 interference is fluctuating.

Falt Case 3

8ow uplink congestion thresholds=

8ow uplink *''I can also cause congestion if the uplink congestion thresholds are set too low.

Falt Case 4

For operators using TM47 they ha-e to input the following information into &T*4N in order to

obtain accurate &8 and )8 power measurements7 e.g. uplink feeder attenuation7 downlink feederattenuation7 uplink TM4 gain7 downlink TM4 insertion loss7 etc. 5therwise7 all power

measurements and algorithms in &T*4N will be messed up.

If the sum of the all parameters for uplink antenna path is less than the sum of the real -alues7 the

uplink *''I then will be o-er"estimated. For instance7









Table 4.2. An example to illustrate te incorrect estimation !or "# RSSI

4 *ecei-ed &8 *''I at the reference power

point

"G<d%m

% *eal TM4 gain @<d%

+ *eal uplink feeder loss ";d%) O

4E%E+

Measured &8 *''I at the *%' port ";d%m

( 0arameter for TM4 gain 3<d%

F 0arameter for uplink feeder loss "3d%

? O )"("F +alculated &8 *''I sent from *%' to *N+ "L@d%m

4.2.3.2 Soltions

Falt Case

0lease read chapter D.3<.@ Fault cases G"3.

Falt Case 2

Soltion

The engineer can ad:ust the parameters in the &8 congestion control to o-ercome this fluctuation

problem. For eample7

• Increase ,set • 8onger iF8yst

Soltion 2

If the ;l,terLoope'lator is set to JSumpK regulator and the radio en-ironment changes

rapidly at the border7 the &(s might generate fluctuating uplink interference to the ad:acent cells.

• 8ower the step siCe for the &8 'I* target7 i.e. ;lSirStep. It should be noted that it is an

*N+ parameter. +hanging it will affect the whole *N+.

• 'plit the cell into se-eral cells.

Falt Case 3

The engineer should check if the uplink congestion thresholds7 i.e. Con' E ,set and

Con'7 match to the planned uplink capacity.

Falt Case 4






0lease refer to 90ower reference 0oint )efinition9 to sol-e this problem.

Back to Top

4.2.4 8i'h #lockin' rate de to ad&ission control

4.2.4. Falt Cases

Falt Case

+ongestion control is blocking new accesses. This is a normal function and only a-oiding the

congestion can sol-e it.

Note= &plink congestion e-ent will not block a new access in hando-er state. +onnecting an

access in hando-er state will not increase additional uplink *''I7 please see Figure D< J&8 *''I-ariation before and after hando-erK.

Falt Case 2

%efore accepting any access types7 admission control checks if the number of the eisting

compressed mode radio links in a cell is larger than the Co&pMode0d&. If many radio links are

in compressed mode7 admission control will block the new access.

Falt Case 3

)8 4'( is not considered to be useful for regular# admission control and the )8 4'( admissionthreshold is normally set to pole capacity7 i.e. maimum allowed in the cell. If not this might be a

problem.

Falt Case 4

4dmission control uses the calculated downlink transmission power to :ustify if the remaining

downlink power resource is enough for a new access. 4 new access blocked due to lack of

downlink power implies that the a-erage downlink transmission power ratio7 i.e. 7

is already -ery close to the thresholds fordownlink power monitor admission policy. 0lease see Figure D.1.









Figure D.1 4ccess blocked due to )8 power monitor admission policy

Falt Case 5

&plink 4'( admission control is not optimised.

Falt Case

There are two other policies to control the resources in a cell. They are=

• )ownlink code allocation admission policy= it is only applicable for non"hando-er and

non"compressed mode admission reBuest. The parameters for this policy are Dlcodead&

and BeMar'inDlCode. When a non"guaranteed access is blocked due to this policy7 theengineer should think about if more non"guaranteed users are allowed.

• /istogram monitor admission policy= it is for the non"guaranteed admission reBuest only.

The parameters for this policy are S%0d&7 S0d& and S320d&. When an access is

blocked due to this policy7 the engineer should think about if more non"guaranteed usersare allowed.

Falt Case $

Improper down"switch timer setting=

The channel switching algorithm measures both &8 and )8 throughput in the dedicated to*4+/AF4+/ e-aluation. When both throughputs are lower than Do"ns"itchThreshold the

Do"ns"itchTi&er starts. %efore the timer epires7 the radio resources7 e.g. &8 4'(7 )8 4'(7

etc.7 in &T*4N are still occupied e-en though the actual radio resources might ha-e be used7 i.e.



there is no contribution in the air interface load. Therefore7 if the timer is set too long7 the rate of

blocking new access becomes -ery high. 0lease see Figure D@ Jimproper down switch timersettingK.

4.2.4.2 Soltions

Falt Case

0lease read chapter D.3<.@ Fault cases G"3.

Falt Case 2

The engineer should check the percentage of radio links in compressed mode. If it is larger than

;<R7 please read chapter D.1.D.@ Fault +ase for solutions. 5therwise7 the Co&pMode0d&

should be gi-en a higher -alue to let more users be in compressed mode.

The counters for the number of attempted Asuccessful )8 compressed mode in 'FA@ method are

pmCmAttDlSf! and pmCmSu""DlSf!7 respecti-ely.

Falt Case 3

• +ase 3= If the a-erage )8 4'(7 i.e. is close to the 0seDl0d&7the engineer should ad:ust 0seDl0d& to a higher -alue.

• +ase @= If the a-erage )8 4'(7 i.e. is larger than the 0seDl0d&

" BeMar'in0seDl7 it is ser-ice differentiation issue7 please read chapter [email protected].



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Figure D.2 4ccess blocked due to )8 4'( admission policy

Falt Case 4

• +ase 3= If the -"r0d& E -"r0d&,set is set lower than the planned maimumallowed downlink transmission power7 the engineer should ad:ust it to the planned -alue.

• +ase @= If the -"r0d& E -"r0d&,set is eBual the planned maimum allowed

downlink transmission power and is

close to or larger than the -"r0d&7 it is a high downlink T power issue. 0lease read

chapter D.3<.@ Fault cases D"L. • +ase ;= If the -"r0d& is eBual to the planned maimum allowed downlink transmission

power and is higher than -"r0d& "

BeMar'inDl-"r7 it is a ser-ice differentiation issue7 please read chapter [email protected].

Falt Case 5

There is one initial check and 1 different solutions suggested for optimisation of uplink 4'(admission +ontrol=

• Firstly7 it should be checked if the Con' is set as the planned maimum allowed &8*''I. 5therwise7 the engineer should ad:ust it back to the planned -alue.









• 'olution 3= If the measured &8 *''I is close to or larger than Con' and the a-erage &8

4'( $4-erage &8 4'( of a cell is eBual to is less than

0se;l0d& it implies that the 0se;l0d& -alue is too high and it should be decreased.5therwise7 new accesses can block the cell. /owe-er7 it does not guaranteed that the &8

*''I will be reduced after decreasing 0se;l0d&. This is because the main contributionto the &8 *''I may be other cells interference. 0lease read chapter D.3<.@ Fault cases G"3 for the solutions of high uplink *''I.

Figure D. (ample for case 3

It should be noted that the units for Con' and ,set are <.3d% and <.3d%m7 respecti-ely. If

Con' is eBual to 3;<7 i.e. 3;d% and ,set is eBual to @<7 i.e. @d%m7 it means that the uplinkcongestion e-ent is triggered when the uplink noise le-el is larger than H33@ E 3; E @ d%m.

• 'olution @= If the measured &8 *''I is close to or larger than Con' and the a-erage &8

4'( is also close to or larger than 0se;l0d&7 please read chapter D.3<.@ Fault cases G"

3 for the solutions to the high uplink *''I.












Figure D.L (ample for case @

• 'olution ;= If the measured &8 *''I is less than or far away from Con' and thea-erage &8 4'( is also close to or larger than 0se;l0d&7 0se;l0d& can be increasedso that more new accesses can be accepted.

Figure D.G (ample for case ;

• 'olution D= If the measured &8 *''I is less than or far away from Con' and the

a-erage &8 4'( is larger than the 0se;l0d& H BeMar'in0se;l7 it is ser-ice

differentiation issue7 please read chapter [email protected].





Figure D.3< (ample for case D

• 'olution 1= The symptoms are same as the ones in case ;. /owe-er7 the solution in thiscase allows more new accesses if they are in hando-er. It can be eecuted by increasing

0se;l0d&,set. It should be noted that increasing 0se;l0d&,set can reduce the

numbers of the hando-er failures and the le-el of &8 *''I caused by uplink near"far

problem. /owe-er7 it will cause higher *4% usage.

Figure D.33 (ample for case 1

Falt Case

'olution 3= ?i-ing low -alue to BeMar'inDlCode will allow more non"guaranteed radio links./owe-er7 more failures in code allocation might conseBuently be caused. 5n the other hand7

changing the Dlcodead& will affect the usage of the code tree.



'olution @= ?i-ing high -alues to S%0d&7 S0d& and S320d& will allow more non"

guaranteed radio links. /owe-er7 more failures in code allocation might conseBuently be caused.

Falt Case $

The Do"ns"itchTi&er should be ad:usted to a suitable -alue. For information how to tune+hannel switching7 see 9&ser )escription9

Back to Top

4.2.5 Ser7ice dierentiation hi'h #lockin' rate to non?

'aranteed ser

4.2.5. ,7er7ie"

4dmission control is the only function ha-ing a capability for ser-ice differentiation. It allows

reser-ing a part of the radio resources for the guaranteed accesses. /owe-er7 it should be noted

that not all admission policies are for ser-ice differentiation. 5nly downlink 4'(7 downlink T power7 uplink 4'( and downlink code allocation admission policies can support this feature.

Figure D.3@ Illustration how the ser-ice differentiation works in admission control











It means the operator is allowed ad:usting the admission thresholds to control the radio resources

according to their ser-ice strategies.

Furthermore7 admission control has a best"effort cleanup mechanism $also called soft congestioncontrol. This mechanism will be acti-ated when Jnon"guaranteed reBuestsK and Jguaranteed

reBuests in non"hando-er stateK are blocked due to the )8 power monitor and )8 code allocationadmission policies. It will trigger down"switch of one eisting non"guaranteed user with a higher bit rate to a lower bit rate $e.g. 0'2DA;LD to 0'2DA3@L or 0'2DA3@L to 0'2DA2D. With this

cleanup mechanism7 the system accessibility to guaranteed" and non"guaranteed users is

impro-ed at the cost of a slightly reduced throughput for non"guaranteed users.

It shall be noted that the best effort mechanism cannot free the uplink resources. It is becausechanging 0'2DA;LD to 0'2DA3@L or 0'2DA3@L to 0'2DA2D will ha-e the same amount of usage in

uplink resources.

4.2.5.2 Falt Cases

Falt Case

Too many resources reser-ed for guaranteed access. The engineer should check if the best effort

admission margins are set too large. This means that too few radio resources are allocated for thenon"guaranteed accesses7 e-en though there are resources a-ailable that are not used for the

guaranteed accesses.

Falt Case 2

%est effort cleanup not started=

4lthough the number of admission denies is high7 the number of switched down non"guaranteedradio connections due to admission control7 i.e. pmNoOfSwDownN#Adm7 might still be -ery

low. This means that the best effect cleanup mechanism does not switch down the non"

guaranteed users to let the new non"guaranteed accesses camp on the cell.

The reason is that these admission blockings are triggered by &8 or )8 4'( admission policies7not )8 power monitor or )8 code allocation admission policies. Therefore the best effort

cleanup mechanism does not start.

4.2.5.3 Soltions

Falt Case

The direct way to sol-e this problem is to decrease the best effort admission margins7 i.e.



• BeMar'in0seDl or

• BeMar'in0se;l or• BeMar'inDl-"r or

• BeMar'inDlCode

For eample7 the non"guaranteed accesses are blocked due to &8 4'( and )8 power admission policies in Figure 3;. Therefore7 both BeMar'in0se;l and BeMar'inDl-"r can be decreasedto allow more non"guaranteed users.

Figure D.3; )ifferent admission policies for ser-ice differentiation.

5f course7 the drawback of this solution is the risk to cause many blockings to the guaranteed

accesses.

Falt Case 2

The engineer should check which admission policy that is causing the blocking.

• If it is due to &8 4'( admission policy7 i.e. a-erage &8 4'( is

close to or larger than 0se;l0d& " BeMar'in0se;l7 it means that the cell lacks uplinkresources. Therefore7 the only way to allow more non"guaranteed users is to reduce the

BeMar'in0se;l.



• If it is due to )8 4'( admission policy7 i.e. a-erage )8 4'( is

close to or larger than 0seDl0d& " BeMar'in0seDl7 it means the )8 4'( and )8

power monitor thresholds do not match each other. The BeMar'in0seDl can bedecreased in order to match with the thresholds in )8 power monitor admission policy.

Back to Top

4.2. 8i'h Con'estion and 0d&ission reEect in an isolated

cell

4.2.. Falt Cases

Falt Case

/omogenous pilot setting in an irregular network=

In the initial phase7 a homogenous pilot power setting is normally deployed in the W+)M4

network. /owe-er7 a mobile network has an irregular traffic distribution. 4s a result7 highlyirregular loading can occur in some cells and as a conseBuence of this7 high user blocking.

Back to 4.4.3.2 Falt Case Back to 4.4.4.2 Falt Case

Falt Case 2

&nwanted large cell co-erage.

The &(s mo-e far way than the planned co-erage. Then the own cell will transmit largerdownlink T power7 i.e. high downlink load. 4t the same time7 the other cells might suffer more

uplink interference7 i.e. high uplink load7 from these &(s due to uplink near"far problem7 please

read chapter D.3@.

Falt Case 3

&ne-en pilot power=

If the difference of pilot power between two neighbouring cells is -ery large7 uplink near far

problems may happen7 please read chapter D.3@. 4s a result7 high uplink interference is generated

to the cell with lower pilot power.

In downlink7 the cell with high pilot power transmits high downlink power of common channels because their parameter settings are relati-e to the pilot power -alue. 4t the same time7 the








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reBuired power for the downlink )0+/ in that cell also increases7 please see eBuation @L.

Finally7 the load of the cell becomes -ery high and then cell blocking may happen.

4.2..2 Soltions

Falt Case

1 solutions are pro-ided for this fault case.

'olution 3=

When a cell has high cell blocking rate7 increasing its path loss can shift the load to the

neighbouring cells. This can be achie-ed by e.g.

• Tilting down the antenna of the cell suffering high blocking rate• *educing the antenna height of the cell suffering high blocking rate

These modifications are eBual to pulling backwards $towards the antenna all co-erage borders7including &8A)8 )0+/s and &8A)8 ++/s and soft hando-er area. The drawbacks are=

• Time and cost consumption.

• The desired co-erage of the cell is modified. +o-erage holes might occur. ,erification of

the co-erage should be done again.

'olution @=

4nother solution to shift the downlink load is to decrease the pilot power -ri&aryCpich-o"er

of the loaded cell. The drawbacks of reducing pilot power are the same as these for the solution ;

in chapter D.L.; Fault +ase @.

'olution ;=

Intentional shifting of load between cells can be achie-ed by changing the siCe of the soft

hando-er area by ad:usting the ndi7idal,set to a negati-e -alue7 see Figure D.3D

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Figure D.3D 'hifting of downlink load with negati-e indi-idual5ffset

When the indi-idual offset of a cell ha-ing high load is set to a negati-e -alue7 the radio link

connected to that cell will be deleted beforehand from the &( acti-e set and a new radio link

from that cell will be added late into the &( acti-e set. Then7 the downlink load of the cell isreduced.

/owe-er7 the change may cause some problems=

• If the negati-e indi-idual offset is set too high7 some strange soft hando-er areas may be

created. For eample7 when a &( mo-es towards the cell with too large negati-e

ndi7idal,set7 it then suffers hea-y downlink interference and the connection might

drop7 see Figure D.31. Furthermore7 the cells connected to that &( need to transmit more

)8 power. 5n the other hand7 the ad:acent cells recei-e high uplink interference due to

uplink near far problem.



Figure D.31 (ample of too large negati-e of indi-idual5ffset

• &plink load of the cell cannot be reduced. This is because the &(s still generate uplink

interference to the cell e-en though they are not connected to it.• This solution may cause different borders in idle and dedicated modes. To sol-e this

problem7 the same -alue should be gi-en to the ndi7idal,set and =,set2sn

$+0I+/ (cANo.

'olution D=

4nother possible solution is to employ a second W+)M4 carrier.

Note= The nterFreAFddMeasndicator should be acti-ated7 i.e. O 37 and SnterSearch should

be set to an acceptable -alue so as to let the &( measure another W+)M4 carrier.

&T*4N supports cell re"selection between carriers in idle mode. Therefore7 if the pilot power

setting is homogenous for all cells in both carriers7 the &( will camp on the cell with the lowestJpath loss times downlink carrier *''IK.

This solution cannot guarantee to shift the new connection establishment to the cell with lower

load7 i.e. lower total downlink T power. It is because the &( will only be shifted to the cell with

lower downlink carrier *''I. /owe-er7 it does not imply that the cell has low downlink load.

'olution 1=



The final possible solution is to add a new site to reduce the high load problem. /owe-er7 it is a

cost" and time"consuming solution because installation work is needed.

Falt Case 2

Two possible solutions=

• Incorrect ndi7idal,set setting7 e.g. too negati-e or too positi-e.

8oad shifting= The ndi7idal,set should be changed to a less negati-e -alue. If the

performance of load shifting becomes no good after the change7 a new site must be added

instead of using ndi7idal,set to shift the load.

4dding the radio link beforehand7 i.e. for corner effect= The ndi7idal,set should be

changed to a not too large positi-e -alue. If the result becomes no good after the change7 a

new site must be added.

• Mobility function failure. For eample7 in Figure D.327 the &( does not hando-er to cell %after passing the J&8 path loss &8 noise riseK balancing point. Then it causes uplink

near"far problem. 0lease read appendi % for the meaning of the J&8 path loss &8

noise riseK balancing point.

Figure D.32 (ample of unwanted large cell co-erage

0lease read chapters D.;.D and D.;.1 for further information.

Falt Case 3

The engineer should check the purpose of the pilot settings.

• 8oad shifting= The engineer should ad:ust the difference of pilot power according to the

margin for pilot power modification. 0lease read chapter D.3@. If the performance of loadshifting becomes no good after the change7 other solutions should be tried7 e.g. setting the

ndi7idal,set to a negati-e -alue.












• )ownlink interference= The engineer should ad:ust the difference of pilot power

according to the margin for pilot power modification. 0lease read chapter D.3@. If therestill has serious downlink interference after the change7 other solutions should be tried7

e.g. tilting antenna.

4.3 8ando7er or cell pdate pro#le&s

4.3. Theory

When in-estigating call disconnection7 the field engineer should monitor the -ariations in the

a-ailable obser-able $#_RSSI 7 CPICH_RSCP i andAor CPICH_Eb/Noi to obtain U RSSI V $#7

U RSCP VCPICH%i and U E c /N oVCPICH%i. This can gi-e hints at the reason of call disconnection7 seeappendi +.

In W+)M47 the recei-ed pilot channel signal strength or Buality is used for hando-er and cell

$re"selection e-aluations. In both e-aluations7 a relati-e comparison between two neighbouringcells is employed. For eample7 the hando-er relationship between cell 4 and % for a &( at a particular location is=

$G

The result of eBuation G concludes two important points=

• (cANo and *'+0 e-aluation criteria will yield the same soft hando-er area location.Furthermore7 if both pilot powers are the same7 the criteria become eBual to path loss

e-aluation.• 'oft hando-er area location is independent of system load unless the pilot borders

$U E c /N oVCPICH O H3L d% mo-e into the soft hando-er area due to too high system load.

Figure D.3 (ample of -ariations of the soft hando-er area location against load.









3. When the load in cell 4 increases7 pilot borders of both cell 4 and % are changed because

the downlink *''I increases simultaneously.@. The pilot border of cell % changes more than the pilot border of cell 47 because the

downlink interference contribution from cell 4 to cell % P Tot%A A # A& is higher than the

contribution P Tot%A A # A from cell % to cell 4.

;. +ase 3= 'oft hando-er area location does not change with load.D. +ase @= 4 part of the soft hando-er area is clipped because the pilot border of cell %

mo-es into the soft hando-er area.

In Figure D.37 the soft hando-er area7 i.e. grey area7 is presented in a simplified way. 4ctually7

the soft hando-er area location is dependent on the mo-ement of the &( as in Figure D.3L.

Figure D.3L. )ifference in soft hando-er area depending on direction of mo-ement

The simplified presentation of the soft hando-er area in Figure D.3 will be used throughout this

guideline.

Back to Top

4.3.2 ,7er7ie"

This chapter is di-ided into 3< sections. %elow follows the sections and descriptions of symptoms

for the faults in each section.

• Dropped Calls in sot or soter hando7er*

These faults are handled in chapter D.;.;. From the dri-e test7 following symptoms will beobser-ed by using T(M' and &(T*=

J**+ connection releaseK 8; message with unspecified reason is sent out from &T*4N

then J**+ connection release completeK 8; message is sent from the &( to &T*4N7 andthen the +onnection drops.

These symptoms can be applied to the radio connection in the connected mode7 i.e. either

cell>)+/ or cell>F4+/.

• Missin' Measre&ent reports









These faults are handled in chapter D.;.D. This problem occurs when the network side fails

to recei-e the measurement report when the &( enters $or lea-es the desired $orundesired cell co-erage area.

From the dri-e test7 the following symptoms will be obser-ed by using T(M' and &(T*=

The &( sends Jmeasurement reportsK to &T*4N but &T*4N does not recei-e them. 5r

the &( does not generate Jmeasurement reportsK e-en if it enters the desired cell co-eragearea or It does not generate Jmeasurement reportsK e-en if it lea-es the undesired cell

co-erage area.

Note= The co-erage area of the desired $or undesired cell can be -erified by using a pilotscanner.

• 8ando7er nction ailre

These faults are handled in chapter D.;.1. The definition of failure of the hando-er

function is the following= &T*4N network side has recei-ed a measurement report froma &( being in cell>)+/ mode7 to reBuest addition of a radio link to the acti-e set.

/owe-er7 the reBuest is not completed.From the performance statistics7 the successful rate of adding a radio link $including the

radio link additions in hando-er replacement to an acti-e set per cell7 i.e.

is -ery low.

• 8i'h acti7e set pdate rate

These faults are handled in chapter D.;.2. From the dri-e test7 it can be obser-ed that the

number of cells in the acti-e set is changed freBuently.

From the performance statistics7 the a-erage rate in acti-e set update7 i.e.

of a cell is -ery high.

It should be noted that the e-ent for hando-er replacement is eBual to Jhando-er additionK

e-ent in one cell plus Jhando-er deletionK e-ent in another cell. Therefore7 the additioncounter7 i.e. pmNoTimesRlAddToA"tSet and deletion counter7 i.e.

pmNoTimesRlDel$rA"tSet $in different cells will both be stepped up during hando-er

replacement. This is the reason why the replacement counter7 i.e.

pmNoTimesRlRepInA"tSet is not included in the eBuation for acti-e set update rate.

• /o sita#le cell

These faults are handled in chapter D.;.. From the dri-e test7 the following symptoms

will be obser-ed=

The &( in idle mode does not camp on any cell. The display of the &( shows Jnoco-erageK or the following happens=

4fter entering no suitable cell7 the &( in cell>F4+/ mode mo-es to idle mode after min $











T31$7 T3$. It is same as connection drop for the &( in the cell>F4+/ mode. 0lease see

Figure 3G.

Figure D.3G +onnection drop when the &( is in cell>F4+/ mode.

T31$ and T3$ are waiting times before the &( mo-es to idle mode when it enters no

suitable cell.

T3157 is a timer for periodic cell update. It is ad:ustable for the operator.

From the pilot scanning7 it is obser-ed=3.The +0I+/>(cANo is eBual or less than the =AalMin or

@.The +0I+/>*'+0 is eBual or less than the =r9le7Min G 0compensation.

• Cell re?selection ailre ? ;< in idle or cellHF0C8 &ode

These faults are handled in chapter D.;.L. From the dri-e test7 the following symptoms arefound by using T(M' and pilot scanner=

3. The &( in cell>F4+/ mode does not send a Jcell updateK message to &T*4N e-en if

it has entered the co-erage area of the desired cell7 or @. The &( in idle mode camps on the wrong cell e-en if it has entered the co-erage area

of the desired cell.

• Cell pdate procedre ailre

These faults are handled in chapter D.;.G. When a &( in cell>F4+/ mode re"selects a

new cell7 the cell update procedure is triggered and the &( sends a Jcell updateK messageto &T*4N to inform about its location. If the cell update procedure fails7 the connection

will be dropped from cell>F4+/ mode to idle mode.

Note=







3. ;?00 @1.;;3",.;..<7 which &T*4N follows7 specifies that the number of the

retransmissions of the Jcell updateK should be /312 if the &( does not recei-e theJcell update confirmationK message. 4fter $/312 E 3T3127 the &( mo-es to the

idle mode7 i.e. connection drops. 0lease see Figure D.@<.

Figure D.@< *epetition of cell update messages $8; retransmissions from the &( point of

-iew

@. ,;<@ is an internal counter in the &(.

;. Total possible number of re"transmissions of the Jcell updateK message is /312.Therefore7 total possible number of transmissions the Jcell updateK message is

/312E3.

D. The default -alues for the (ricsson only parameters T312 and /312 are 3 secondand ; times7 respecti-ely. Therefore7 the &( mo-es to the idle mode D seconds

after sending the first Jcell updateK message if it does not recei-e the Jcell update

confirmationK message.1. From &T*4N point of -iew7 the time of starting to release &T*4N resources for

a &( is Cch!aitCT after recei-ing the last Jcell updateK message from that &(.

This timer is changeable for the operator and the default -alue for the

Cch!aitCT is D1 minutes. /owe-er7 changing it will affect the whole *N+.0lease see Figure D.@3.

Figure D.@3 +ell update from &T*4N point of -iew.



2. If no suitable cell is detected7 the T3$ is started for the &(. If it epires the &(

mo-es to idle mode. T3$ is an (ricsson only parameter with default -alue 3L<seconds. Therefore7 no suitable cell ne-er happens during the repetition of the cell

update7 i.e. $/312E3T312 seconds.

• Many intra?reAency cell re?selections

From the dri-e test7 it can be obser-ed that the &( freBuently re"selects the cells in thecurrent freBuency. These faults are handled in chapter D.;.3<.

• Many inter?reAency cell re?selections

From the dri-e test7 it can be obser-ed that the &( freBuently re"selects the cells in

different freBuencies. These faults are handled in chapter D.;.33.

• Many cell pdate atte&pts

From the performance statistics7 the total number of attempted cell update procedures7 i.e. pmNoCell"p'Attempt 7 which includes cell re"selection and periodic update7 per cell is

-ery high. These faults are handled in chapter D.;.3@.

Back to Top

4.3.3 Dropped Calls in sot or soter hando7er

4.3.3. Falt Cases

Falt Case acti7e set pdate ti&er e9pires

In soft or softer hando-er7 when the coming cell has allocated resources for a new radio link7

&T*4N sends an Jacti-e set updateK message to the &( and starts the acti-e set update timer. If

&T*4N recei-es an Jacti-e set update completeK message from the &(7 the timer will bestopped. 5therwise7 &T*4N waits for the timer to epire. 4fter the epiry7 &T*4N orders the

&( to release the connection.


• 4fter the &( sends the Jacti-e set update completeK message to &T*4N7 it is still usingthe old neighbouring cell list but considers the hando-er had been completed no matter if&T*4N recei-es that message. If &T*4N does not recei-e the complete message or the

contents of the message cannot be decoded correctly7 &T*4N will not send out the

Jmeasurement controlK message to update the neighbouring cell list for the &(.

Falt Case 2 &easre&ent control ailre













4fter &T*4N recei-es an Jacti-e set update completeK from the &(7 it sends a Jmeasurement

controlK message to inform the &( about the new neighbouring cells. If the &( cannot decode theJmeasurement controlK message and sends a Jmeasurement control failureK message back to

&T*4N7 &T*4N considers that the &( will not measure on ordered neighbouring cells and also

not report on entering these cells. To a-oid that the &( runs into a cell and starts interfering7

&T*4N orders the &( to release the connection.

Falt Case 3 &onitored set cell #etter than the #est ser7in' cell

When addition or replacement of a radio link fails and the Buality of this radio link is better than

that of the best cell in the acti-e set7 &T*4N orders to release the connection in order to a-oid

ecessi-e congestion caused from that &(.

Figure D.@@ (ample of monitored set cell better than the best ser-ing cell

8ike what is described in chapter D.;.;.3 Fault +ase 37 the &( might think the process of the

hando-er has been completed after sending the Jacti-e set update completeK. /owe-er7 it might

not be completed from &T*4N point of -iew. When the &( sends the Jmeasurement reportK to

&T*4N to report the Bualities of the cells in the acti-e set7 &T*4N will only consider this fakeacti-e set cell as a monitored set cell. If the Buality of this fake acti-e set cell is better than that of

the best cell in acti-e set7 &T*4N will order to release the connection.

4.3.3.2 Soltions

Falt case

It is possible that=

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204-2.html#4.3.3.1FC1%234.3.3.1FC1




• &T*4N has sent the Jacti-e set updateK to the &( but the &( does not recei-e it. The

reason is because of poor Buality in the downlink. 0lease read chapter D.3<.@ Fault +ases@;"@2.

• The &( sends the Jacti-e set update completeK to &T*4N but &T*4N does not recei-e

it. It is due to poor uplink Buality. 0lease read chapter D.3<.@ Fault +ases 3L"@@.•

The &( sends wrong contents in the complete message and &T*4N cannot decode itcorrectly. 0lease check what content the &( sent in the Jacti-e set update completeK

message.

Falt Case 2

The reason of ha-ing decoding problem is due to poor downlink Buality. 0lease read chapterD.3<.@ Fault +ases @;"@2.

Falt Case 3

0lease read chapters D.;.D and D.;.1.

Back to Top

4.3.4 Missin' Measre&ent reports

4.3.4. Falt Cases

Falt Case poor plink Aality

If the &( sends a Jmeasurement reportK to &T*4N and &T*4N does not recei-e it7 it implies

the Buality of the uplink may not be good.

Falt Case 2 incorrect hando7er series

The &( might hando-er to wrong cells7 i.e. incorrect cells in the acti-e set at the problematic

area7 and these acti-e set cells do not ha-e neighbouring relationship with the desired cell. 4s aresult7 e-en though the &( enters the desired cell co-erage area according to the original plan7

hando-er e-ent is not detected.

/ando-er series could be messed up because=

• /ando-er function failure or• Too many unnecessary hando-er relationships or

• &nwanted cell o-ershooting

Falt Case 3 ? &issin' nei'h#orin' relationship






















/ando-er e-ents might be o-erlooked because=

• There are many cells in the monitored set the process for searching the pilot channel

might become -ery slow.• The &( mo-es -ery fast.

Falt Case % s&all sot hando7er area

)ue to radio propagation7 the soft hando-er area between two cells might be -ery small7 e.g.

corner effect. Then7 a hando-er e-ent is probably o-erlooked.

4.3.4.2 Soltions

Falt Case


Falt Case 2

'olution 3=

If the problem is due to a hando-er function failure7 please read chapter D.;.1.

'olution @=

If the problem is due to too many unnecessary hando-er relationships7 the engineer shouldcarefully :ustify the usefulness of the hando-er relationships and remo-e the unnecessary ones.

Note= If necessary relationships are deleted by mistake7 more connection drops and highdownlink interference may happen.

'olution ;=

If the problem is due to o-ershooting from an unwanted cell7 the engineer should check why the

cell is o-ershooting.

• If the pilot power of the unwanted cell is too high7 the engineer should reduce its pilot power back to a suitable le-el.

• If the pilot power of the unwanted cell is normal7 please employ solution @ and ; in

chapter D.L.; Fault +ase @ to o-ercome the o-ershooting problem.

Falt Case 3











The direct solution is to add the desired cell into the neighbouring cell lists of the cells in the

acti-e set. %ut it should be noted that too many neighbouring cell relationships might slow downthe search for the pilot channels in the &(.

Falt Case 4

0lease read chapter D for descriptions and solutions about pilot pollution.

Falt Case 5

'olution 3=

If the problem is due to too many unnecessary hando-er relationships7 the engineer shouldcarefully :ustify the usefulness of the hando-er relationships and remo-e the unnecessary ones.

Note= If necessary relationships are deleted by mistake7 more connection drops and high

downlink interference may happen.

'olution @=

The engineer should put the neighbouring cells in a desired order so the highest ranked cellsappear in the top of the list.

Falt Case

The ndi7idal,set should be changed to a not too large negati-e -alue. If the performance of

load shifting becomes no good after the change7 a new site must be added instead of using

ndi7idal,set to shift the load.

Falt Case $

If the problem is due to too many unnecessary hando-er relationships7 the engineer should

carefully :ustify the usefulness of the hando-er relationships and remo-e the unnecessary ones.

Note= If necessary relationships are deleted by mistake7 more connection drops and high


Falt Case %

'olution 3=

?i-ing a positi-e -alue to ndi7idal,set of the target cell can enlarge the soft hando-er area.

'olution @=



Falt Case poor plink Aality

The &( has sent Jacti-e set update completeK or Jacti-e set update failureK to &T*4N7 but

&T*4N does not recei-e it. The reason could be poor Buality in the uplink. The acti-e set updatetimer will epire and the connection will be released7 please read fault case 3.

Falt Case $ ;< trans&its "ron' contents in the &essa'e

&T*4N has recei-ed the Jacti-e set update completeK7 but it cannot recogniCe the contents in the

complete message. The reason might be that the &( sends wrong contents in the Jacti-e setupdate completeK message. Thus7 &T*4N cannot recogniCe the contents and stops the acti-e set

update timer. 4s a result7 the acti-e set update timer will epire and the connection will be

released.

Falt Case % acti7e set pdate ailre

&T*4N has recei-ed the Jacti-e set update failureK. This might be a &( problem.

Falt Case 00L2 esta#lish&ent ailre

&T*4N has recei-ed the Jacti-e set update completeK but it sends out the Jacti-e set updateK a

second time to order the &( to de"allocate the resource for the new radio link. 5ne reason can be

448@ establishment failure.

Falt Case 1 plink in?synchroniation at hando7er

The target *%' does not send Jradio link restore indicationK to the *N+. 5r7 in the proper

hando-er case7 the target *%' allocates *4% resources and starts the recei-ing after gettingJradio link setup reBuestK message from the *N+. J*adio link restore indicationK is sent when

the target *%' is synchroniCed with the &(7 thus a missing Jradio link restore indicationK canmean problems in uplink in" synchroniCation.

&plink in"synchroniCation can be caused due to=

• &plink and pilot co-erage imbalance

• The ndi7idal,set of the target cell is gi-en a too large positi-e -alue.






Figure D.@;. &plink or downlink in"synchroniCation due to improper setting in indi-idual5ffset

Falt Case do"nlink in?synchroniation at hando7er

In the Jmeasurement reportK7 which is sent from the &( after getting the Jmeasurement controlK

from &T*4N7 the target cell is not in the acti-e set. The reason might be problems withdownlink in"synchroniCation.

)ownlink in"synchroniCation problems can be caused due to=

• Intended )8 )0+/ and pilot co-erage imbalance

• Not intended )8 )0+/ and pilot co-erage imbalance

• Too low initial downlink 'I* target• The indi-idual5ffset of the target cell is gi-en too large positi-e -alue. 0lease see Figure

D.@;.

4.3.5.2 Soltions

Falt Case

0lease read chapter [email protected].

Falt Case 2

0lease read chapters D.D.; and D.D.D.

Falt Case 3

0ossible reasons are=

• The target *%' is blocked.

• The hardware in the target *%' is faulty.

• Transport network problem7 i.e. Iub andAor Iur











Falt Case 4

0lease read chapter D.3<.@ Fault +ases @;"@2.

Falt Case 5

No solution is pro-ided since it is mobile dependent.

Falt Case


Falt Case $

0lease check if the contents in the message sent from the &( are incorrect.

Falt Case %

No solution is pro-ided since it is mobile dependent.

Falt Case

The engineer should check if the transport network has problems or if the transport parametersare incorrect.

Falt Case 1

'olution 3=

For uplink and pilot co-erage imbalance7 please read chapter D.L.; Fault +ase 3@"3.

'olution @=

+hange indi7idal,set to Cero.

Falt Case

'olution 3=

For Jintended )8 )0+/ and pilot co-erage imbalanceK7 the engineer should consider if it is

necessary to pro-ide full co-erage for that )8 )0+/ type or not.

If a change of co-erage is needed the combination of the parameters &a9-"rMa97

inter-"rMa97 &in-"rMa97 &ini&&ate7 nterate and Ma9ate shall be tuned. For

further information7 see the +apacity Management +0I.













Figure D.@D Improper hando-er parameter settings causing ping pong hando-ers

Falt Case 2 pilot polltion in dedicated &ode

0ilot pollution can lead to high update rate in the acti-e set.

Falt Case 3 &any nnecessary hando7er relationships

Too many unnecessary hando-er relationships can lead to high update rate in the acti-e set.

4.3..2 Soltions

Falt Case

The default -alue for eportin'an'e# is set to 1 d%7 i.e. @d% larger than the default -alue ofeportin'an'ea. 8ysteresisc has a default -alue of 3d%.

It should be noted these hando-er parameters are *N+ parameters. It means changing them will

affect all cells in the *N+.

Falt Case 2

0lease read chapter D for descriptions and solutions about pilot pollution.

Falt Case 3

The engineer should carefully :ustify the usefulness of the hando-er relationships and remo-e the

unnecessary ones.

Note= If the necessary relationship is deleted by mistake7 more connection drops and high


Back to Top

4.3.$ /o sita#le cell

4.3.$. Falt Cases

Falt Case hi'h do"nlink intererence

4 possible reason to Jno suitable cellK is the same as that for the pilot channel failure due to high

downlink interference.







Falt Case 2 ot o pilot co7era'e de to Aality

4nother possible reason for Jno suitable cellK is the same as that for the pilot channel failure due

to out of pilot co-erage.

Falt Case 3 ot o pilot co7era'e de to si'nal stren'th

If the &( mo-es far away from the cell and the CPICH_RSCP is eBual or less than $=r9le7Min

E 0compensation7 Kno suitable cellK happens.

Note=

3. 0compensation is eBual to the maimum -alue of JMa9T9-o"er;l " output power of the&( according to its classK and Cero.

@. Inter"*4T and inter"freBuency cell re"selection is triggered by CPICH_Ec/No Buantity.

Therefore7 if the CPICH_Ec/No is larger than the =AalMin E S0TSearch $or E

SnterSearch7 inter"*4T $or inter"freBuency cell re"selection will not be triggered e-enthough the CPICH_RSCP is eBual or less than the $=r9le7Min G 0compensation .

Falt Case 4 i&proper inter?0T search para&eter settin'

If the system is allowed to ha-e inter"*4T cell re"selection but the inter"*4T search parameter

S0TSearch is set as Cero or a negati-e -alue7 no suitable cell might happen when theCPICH_Ec/No gets eBual to or less than =AalMin. 0lease see Figure D.@1.

Figure D.@1 (ample of improper S0TSearch setting

Falt Case 5 i&proper "ron' inter?reAency search para&eter settin'



If the system is allowed to ha-e inter"freBuency cell re"selection but the inter freBuency search

parameter SnterSearch is set as Cero or a negati-e -alue7 no suitable cell might happen whenthe CPICH_Ec/No gets eBual to or less than =AalMin. 0lease see Figure D.@2.

Figure D.@2 (ample of improper SnterSearch setting

Falt Case hi'h restriction on cell (re)?selection para&eters

If the cell $re"selection parameters are set to ha-e -ery high restrictions7 no suitable cell may

happen e-en though the actual Buality and signal strength of the pilot is good enough to pro-ideco-erage.

The parameters for cell $re"selection are=

• =AalMin

• =r9le7Min

• Ma9T9-o"er;l

Note= Ma9T9-o"er;l should be set as the one used in dimensioning or cell planning. Foreample7 if the maimum &( T power is assumed to be @Dd%m for all &( classes in the

dimensioning7 the Ma9T9-o"er;l should be set to be @Dd%m. If it is set too high7 theJ0compensationK7 which is eBual to maimum -alue of Jthe Ma9T9-o"er;l " output power ofthe &( according to its classK and Cero7 becomes large and the idle mode cell co-erage for some

&( classes will then shrink.

4.3.$.2 Soltions



Falt Case

0lease read chapter D.L.; Fault +ase 3";.

Note=

3. The CPICH_Ec/No triggered to determine the pilot channel failure is H32d%. /owe-er7the CPICH_Ec/No triggered to determine the no suitable cell is =AalMin.

@. If the system is allowed to ha-e inter"*4T or inter"freBuency cell re"selection and the

search parameters are set properly7 abo-e reason is not -alid.

Falt Case 2

0lease read chapter D.L.; Fault +ase D"1.

Note= 'ee Note for Fault +ase 3.

Falt Case 3

The engineer should check the reason for lack of pilot co-erage.

• If it is because of lack of outdoor co-erage7 a new outdoor site should be added.

• If it is because of lack of indoor co-erage7 a new indoor site should be added.• If it is because the signal is blocked by a building7 change the antenna configuration or try

to mo-e the site first. If none of these solutions work7 a new outdoor site should be added.

Falt Case 4

If the system is allowed to ha-e inter"*4T cell re"selection7 the S0TSearch should be set to a positi-e -alue.

Falt Case 5

If the system is allowed to ha-e inter"freBuency cell re"selection7 the SnterSearch should be set

to a positi-e -alue.

Falt Case

The engineer should correct these parameters to suitable -alues=

• =AalMin

• =r9le7Min

• Ma9T9-o"er;l

Back to Top











4.3.% Cell re?selection ailre ? ;< in idle or cellHF0C8

&ode

4.3.%. Falt Cases

Falt Case ? incorrect cell re?selection series

The &( might ha-e camped on wrong cell and this cell does not ha-e a neighbouring relationshipwith the desired cell.

*e"selection series could be messed up because=

• +ell update procedure failure $for the &( in cell>F4+/ mode or

• Too many unnecessary neighbouring relationships or• &nwanted cell o-ershooting

Falt Case 2 ? &issin' nei'h#orin' relationship

4 possible reason why the cell re"selection detection fails is because of missing neighbouring cell

relationship. In the dri-e test7 the engineer can monitor the neighbouring cell window to check if

the desired cell is included in the neighbouring cell list.

Falt Case 3 pilot polltion in idle or cellHF0C8 &ode

0ilot pollution can lead to failure in the cell re"selection e-ent detection.

Falt Case 4 i&proper cell re?selection oset settin'

If the cell re"selection offset =,setsn (C-C8 SC-) or =,set2sn (C-C8 <c>/o)

between the camped cell and the desired cell is too positi-e7 the ranking in the cell re"selection procedure of the desired cell becomes -ery low. Therefore7 e-en though the actual Buality and

signal strength of the pilot in the desired cell are good enough to pro-ide co-erage7 the &( does

not camp on the cell7 i.e. cell re"selection fails.

Falt Case 5 slo" searchin' or ast &o7in' ;<

+ells might be o-erlooked because=

• There are many cells in the neighbouring cell list. The process for searching pilot channel

might become -ery slow.

• The &( mo-es -ery fast.

Falt Case s&all cell o7erlappin' area







The cell o-erlapping area between two cells might in some cases be -ery small7 for eample due

to corner effects. Then7 cell re"selection is probably o-erlooked.

4.3.%.2 Soltions

Falt Case

'olution 3=

If the problem is due to cell update function failure7 please read chapter D.;.G.

'olution @=

If the problem is due to too many unnecessary neighbouring relationships7 the engineer should

carefully :ustify the usefulness of these relationships and remo-e the unnecessary ones.

'olution ;=

If the problem is due to o-ershooting of an unwanted cell7 the engineer should check why the cellis o-ershooting.

• If the pilot power of the unwanted cell is too large7 the engineer should decrease its pilot

power to a suitable le-el.

• If the pilot power of the unwanted cell is normal7 please employ solution @ and ; inchapter D.L.; Fault +ase @ to o-ercome the o-ershooting problem.

Falt Case 2

The direct solution is to add the desired cell into the neighbouring cell list. /owe-er7 it should be

noted that too many neighbouring cell relationships might slow down the search for the pilot

channels in the &(.

Falt Case 3

0lease read chapter D.;.D for descriptions and solutions about pilot pollution.

Falt Case 4

=,setsn (C-C8 SC-) or =,set2sn (C-C8 <c>/o) should be changed to not too large

positi-e -alues.

Note= +hanging cell re"selection offset may cause different borders in idle and dedicated modes.To sol-e this problem7 the same -alue should be gi-en to the ndi7idal,set and =,setsn

(C-C8 SC-) or =,set2sn (C-C8 <c>/o) .











Falt Case 5

The engineer should carefully :ustify the usefulness of the neighbouring relationships and remo-e

the unnecessary ones. If the necessary relationship is mistakenly deleted7 high downlinkinterference may happen due to missing relationship.

Falt Case

The engineer can change the antenna configuration or re"locate the sites so that the cell

o-erlapping area becomes larger. 5b-iously7 it is a cost and time"consuming solution.

Note= unlike the soft hando-er area7 modifying system parameters cannot enlarge an o-erlappingarea between cells. 0lease see Figure D.@.

Figure D.@ ,ariations of soft hando-er area and idle $cell>F4+/ mode co-erage when

changing the system parameters

In case 37 the parameter settings for both cells are normal. In case @7 a negati-e -alue is gi-en to

the cell re"selection offset in cell 4. 5n the other hand7 both indi7idal,set and cell re"



selection offset in cell % are set as the same -alues7 but positi-e. It can be obser-ed that e-en

though the soft hando-er area and idle $cell>F4+/ mode co-erage are changed in case @7 theactual o-erlapping area is still the same as before.

Back to Top

4.3. Cell pdate procedre ailre

4.3.. Falt Cases

Falt Case rando& access procedre pro#le&

The &( repeatedly transmits the Jcell updateK message to &T*4N but &T*4N does not recei-e

it.

The reason for this is because of problems in the random access procedure.

Falt Case 2 cell pdate nction ailre

&T*4N recei-es the Jcell updateK message but it does not send the Jcell update confirmK

message to the &(.

0ossible reasons for this are due to some miscellaneous problems7 like below=

• When the )"*N+ or '"*N+ cannot allocate any *NTI -alues7 &T*4N orders to release

the connection and sends a J**+ connection releaseK message to the &( or• When the *N+"Id and the +"Id are not correctly recei-ed by the '"*N+7 &T*4N orders

to release the connection and sends a J**+ connection releaseK message to the &( or• When the *N+"Id and the +"Id are not correctly recei-ed by the )"*N+7 the cell update

procedure will be stopped and all reser-ed resources at the )"*N+ will be released or

• When the Iur common transport channels cannot be established7 e.g. due to time"out or noresources a-ailable7 the signalling connections will be released or

• When the *N+ recei-es an (**5* IN)I+4TI5N message7 the *N+ will ignore the

message and continue with the procedure.

Falt Case 3 S?CC-C8 (F0C8) ailre

&T*4N sends the Jcell update confirmK message to the &( but the &( does not recei-e it.There is no power control on the common channels. For that reason7 the engineer has to carefully

plan enough F4+/ power to fulfil the assumed downlink load. If mistake is done during the

power calculation or the real load of the downlink carrier is larger than the assumed le-el7 theF4+/ might not co-er the whole cell.







4.3..2 Soltions

Falt Case

0lease read chapter D.3.@.

Falt Case 2

No solutions are pro-ided.

Falt Case 3


Back to Top

4.3.1 Many intra?reAency cell re?selections

4.3.1. Falt Cases

Falt Case i&proper re?selection hysteresis settin'

4 possible reason is that re"selection hysteresis =hyst or =hyst 2 is set too low7 e.g. < d%.

Figure D.@L Intra"freBuency cell re"selection in ping pong when re"selection hysteresis is set to be

Cero.

Falt Case 2 inconsistent cell re?selection oset settin'

The cell re"selection offset =,setsn (C-C8 SC-) or =,set2sn (C-C8 <c>/o) is percell relation. If the offset from source cell to target cell is a positi-e -alue7 the offset from the

target cell to the source cell must be the same -alue but negati-e. 5therwise7 the &( might

repeatedly camp on them7 i.e. ping"pong occurs.

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204.html#CHAPTER4.1.2





ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204.html#CHAPTER4.1.2






Falt Case 3 pilot polltion in the idle or cellHF0C8 &ode

0ilot pollution can lead to many cell re"selections.

Falt Case 4 &any nnecessary cell re?selection relationships

Too many unnecessary cell re"selection relationships can lead to many cell re"selections.

4.3.1.2 Soltions

Falt Case

The engineer should set =hyst or =hyst 2 to be larger than Cero7 e.g. @d%

Falt Case 2

The engineer should correct the cell re"selection offsets between two neighbouring cells to make

them consistent.

Falt Case 3

0lease read chapter D.;.D for descriptions and solutions about pilot pollution.

Falt Case 4

The engineer should carefully :ustify the usefulness of the cell re"selection relationships andremo-e the unnecessary ones.

Note= If a necessary relationship is deleted by mistake7 the cell re"selection might fail.

Back to Top

4.3. Many inter?reAency cell re?selections

4.. Falt Cases

Falt Case hi'h do"nlink intererence

4 possible reason causing many inter"freBuency cell re"selections is the same as that for the pilot

channel failure due to high downlink interference.









Note= The CPICH_Ec/No triggered to determine the pilot channel failure is H32d%. /owe-er7 the

CPICH_Ec/No triggered to determine for inter"freBuency cell re"selection is =AalMin E

SnterSearch.

Falt Case 2 ot o pilot co7era'e de to Aality

4 possible reason causing many inter"freBuency cell re"selections is same as that for the pilot

channel failure due to out of pilot co-erage.

Note= The CPICH_Ec/No triggered to determine the pilot channel failure is H32d%. /owe-er7 theCPICH_Ec/No triggered to determine for inter"freBuency cell re"selection is =AalMin E

SnterSearch.

Falt Case 3 i&proper inter?reAency search para&eter settin'

If the inter"freBuency search parameter SnterSearch is set to a too high positi-e -alue7

unnecessary inter"freBuency cell re"selection may be caused.

Falt Case 4 pin'?pon' in inter?reAency cell re?selections

The &( may repeatedly re"select select two neighbouring cells in different freBuencies. This can

occur during the following condition=

3. The operator employs a second carrier7 which totally co"sites with the first carrier and

@. The pilot power setting of the second carrier is same as that of the first carrier and;. The =alMeas=antity is set to be 37 i.e. CPICH_RSCP 7

In Figure D.@G7 the CPICH_RSCP s of the cells in both carriers 3 and @ are similar because twocarriers are co"located and the pilot power settings of them are the same. If the loads in both

carriers are similar7 the inter"freBuency hando-er freBuently happens between two co"locatingcells.



Figure D.@G Illustration of the ping pong problem in the inter"freBuency cell re"selection

4.3..2 Soltions

Falt Case

0lease read chapter D.L.; Fault +ase 3";.

Falt Case 2

0lease read chapter D.L.; Fault +ase D"1.

Falt Case 3

Modify the SnterSearch to a suitable -alue7 e.g. Dd%.

Falt Case 4

5ne possible solution is to set the =alMeas=antity to be @7 i.e. CPICH_Ec/No.

Back to Top











4.3.2 Many cell pdate atte&pts

4.3.2. Falt Cases

Falt Case

Many intra"freBuency cell re"selections

Falt Case 2

Many inter"freBuency cell re"selections

Falt Case 3

If the -alue of the 0eriodic cell update timer7 i.e. T3157 is set too short many cell update attemptsmight occur. This is a timer for how often the &( shall make periodic cell updates.

4.2.2 Soltions

Falt Case

0lease read chapter D.;.3<.

Falt Case 2

0lease read chapter D.;.33.

Falt Case 3

The engineer should ad:ust T315 to a suitable -alue. The default -alue is ;< minutes.

Back to Top

4.4 8ard"are pro#le&s4.4. ,7er7ie"

Three kinds of hardware problems are listed here=

• 'wapped feeders















• 5ut of T *esource

From the performance statistics7 many numbers of setup failures due to out of T%

resource7 e.g. pmSetup$ailuresSf% or pmSetup$ailuresSf'( 7 etc has high -alues7 isfound. 5ut of T% resource is caused due to too many downlink connections in the *%'.

Note= Many downlink connections do not imply that the cell transmits high )8 T power.

It could be that the cell has many connections but each connection only needs -ery small

)8 power.

• 5ut of *4% *esource

From the performance statistics7 many numbers of setup failures due to out of *4%

resource is found. 5ut of *4% resource is caused due to too many uplink connections in

the *%'.

Note= Many uplink connections do not imply that the cell recei-es high &8 *''I. It could be that the cell has low &8 interference from the &(s in other cells.

Back to Top

4.4.2 S"apped eeders

4.4.2. Falt Cases

'wapped feeders can cause many ma:or problems in the network7 e.g. no downlink co-erage7 nouplink co-erage or high &8A)8 interference. %elow are some $not all eamples of swapped

feeders=







Figure D.;< (ample of swapped feeders

(amples of monitoring tools for swapped feeder problems are pilot scanner and T(M'. Thesymptoms can be high downlink interference7 slightly high &( T power7 connection setup

failure during random access or uplink )0+/ synchroniCation procedures7 no downlink

co-erage7 hando-er failure7 wrong scrambling code co-erage7 etc.

For eample7 please refer to Figure D.;<=



Table D.D 'ymptoms of swapped feeders

Case Sy&pto& Monitorin'

tool

3 'crambling codes co-er wrong directions. 0ilot 'canner

/ando-er may fail from other cells to them due to improperhando-er relationship or uplink )0+/ synchroniCation problem.

+onnection setup will fail during random access or uplink )0+/synchroniCation procedures.

T(M'

@ No downlink co-erage7 i.e. low *'+0 in some areas.

/igh downlink interference7 i.e. low (cANo and high )8 *''I insome areas.

'crambling codes co-er wrong directions.

0ilot scanner

If the &( tries to connect to cell % in the cell 4 area7 connectionsetup may fail during random access or uplink )0+/

synchroniCation procedures.

If the &( tries to hando-er to cell % in the cell 4 area7 it may alwayssend additional hando-er e-ents to &T*4N but hando-er function

always fails due to uplink )0+/ synchroniCation problems.

The &( connected to cell 4 transmits slightly higher &( T power

than in the normal feeder case due to higher &8 interference7 i.e.higher &8 *''I.

The connection may drop if the &( mo-es to the planned cell % area

due to no co-erage.

T(M'

; The &( connected to cell 4 andAor cell % transmits slightly higher

&( T power than in the normal feeder case due to higher &8

interference7 i.e. higher &8 *''I.

T(M'

D +onnection setup will fail in both cells during random access or

uplink )0+/ synchroniCation procedures.

/ando-er will fail from other cells to either cell 4 or cell % due touplink )0+/ synchroniCation problems or improper hando-er

relationship.

T(M'

1 No downlink co-erage7 i.e. low *'+0 in some areas

/igh downlink interference7 i.e. low (cANo and high *''I in some

areas

'crambling codes co-er wrong directions

0ilot scanner

+onnection setup will fail in cell 4 during random access or uplink T(M'



)0+/ synchroniCation procedures.

+onnection may drop if the &( mo-es to the planned cell % area dueto no co-erage.

/ando-er will fail from other cells to either cell 4 due to uplink)0+/ synchroniCation problem or improper hando-er relationship.

The &( connected to cell % transmits slightly higher &( T powerthan in the normal feeder case due to higher &8 interference7 i.e.

higher &8 *''I.

4.4.2.2 Soltions

The direct solution for all fault cases is to check that feeders are not crossed and that thescrambling codes are set correctly for all the cells in the site.

Back to Top

4.4.3 ,t o TIB resorce

4.4.3. Falt Cases

Falt Case

/omogenous pilot setting in an irregular network

Falt Case 2

Many users in )8 'FA@ compressed mode

Falt Case 3

Many users in softAsofter hando-er

Falt Case 4

/igh downlink traffic in the network

Falt Case 5

Improper )8 admission thresholds







Falt Case

Wrong T% hardware dimensioning

4 mistake is possibly done in the T% hardware dimensioning. 4s a result7 T% hardware

resources are not enough.

Falt Case $

Improper down"switch timer setting

The channel switching algorithm measures both &8 and )8 throughputs in the dedicated to

*4+/AF4+/ e-aluation. When both throughputs are lower than Do"ns"itchThreshold the

Do"ns"itchTi&er starts. %efore the timer epires7 the T% resources are still occupied e-en

though the )8 power of the )0+/ might ha-e stopped transmitting7 i.e. there is no contribution

in the air interface load. Therefore7 if the timer is set too long7 the utiliCation of the T% will be

-ery low. 0lease see Figure D.;3.

Figure D.;3 Improper downswitch timer setting

4.4.3.2 Soltions



Falt Case

0lease read chapter [email protected] Fault +ase 3.

Falt Case 2

0lease read chapter D.3<.@ Fault +ase D.

Falt Case 3


Falt Case 4

0lease read chapter D.3<.@ Fault +ase .

Falt Case 5

0lease read chapter D.3<.@ Fault +ase L.

Falt Case

The T% dimensioning should be redone again.

Falt Case $

The Do"ns"itchTi&er should be ad:usted to a suitable -alue. It should be noted that if the timer

is set too short7 a high amount of channel switches might be caused. &sage of the F4+/ channeland load of the signalling are conseBuently increased.

The Do"ns"itchTi&er is an *N+ parameter. +hanging it will affect all cells in the *N+.

Back to Top

4.4.4 ,t o 0IB resorce

4.4.4. Falt Cases

Falt Case

/omogenous pilot setting in an irregular network

Falt Case 2






















Many users in softAsofter hando-er

Falt Case 3

Many users in &8 'FA@ compressed mode

Falt Case 4

/igh uplink traffic in the network

Falt Case 5

Improper &8 admission thresholds

Falt Case

Wrong *4% hardware dimensioning

4 mistake is maybe done in the *4% hardware dimensioning. 4s a result7 *4% hardware

resources are not enough.

Falt Case $

Improper down"switch timer setting

+hannel switching algorithm measures both &8 and )8 throughputs in the dedicated to

*4+/AF4+/ e-aluation. When both throughputs are lower than Do"ns"itchThreshold the

Do"ns"itchTi&er starts. %efore the timer epires7 the *4% resources are still occupied e-enthough the &( might ha-e stopped transmitting7 i.e. there is no contribution to the air interface

load. Therefore7 if the timer is set too long7 the utiliCation of the *4% might be -ery low. 0lease

see Figure D.;3.

4.4.4.2 Soltions

Falt Case

0lease read chapter [email protected] Fault +ase 3.

Falt Case 2


Falt Case 3









0lease read chapter D.3<.@ Fault +ase G.

Falt Case 4


Falt Case 5


Falt Case

The *4% dimensioning should be redone again.

Falt Case $

The Do"ns"itchTi&er should be ad:usted to a suitable -alue. It should be noted that if the timeris set too short7 a high amount of channel switches might be caused. The usage of the F4+/channel and load of the signalling are conseBuently increased.

The Do"ns"itchTi&er is an *N+ parameter. +hanging it will affect all cells in the *N+.

4.5 0T 8ando7er

4.5. ,7er7ie"

I*4T hando-er problems is di-ided into ; areas

• Failures to do I*4T /ando-ers or +ell changes

• The amount of I*4T /ando-ers is too big7 loading the system unnecessarily high

• +ompressed mode problems

Back to Top

4.5.2 ,t'oin' inter?0T hando7er nction ailre

4.5.2. Falt Cases

Falt Case

The *4N40 message J*elocation preparation failureK is sent to the '"*N+ from the circuited

switched core network. This is because no resources are a-ailable in ?'M network.




















Falt Case 2

The *4N40 message J*elocation cancelK with cause -alue Jrelocation cancelled $3<K is sent

out to the circuited switch core network from the '"*N+.

The reason for this is that &T*4N cannot fulfil the reBuest from the ?'M side. The ?'M targetsystem has allocated resources and sends a J*elocation commandK to the '"*N+. The command

includes what *4%s that shall be released. If &T*4N cannot fulfil the reBuest7 a J*elocation

cancelK with cause -alue Jrelocation cancelled $3<K is sent out to the circuited switch corenetwork from the '"*N+. It should be noted that the connection is still kept.

Falt Case 3

The *4N40 message J*elocation cancelK with cause -alue JT*(85+prep epiry $;K is sent out to

the circuited switch core network from the '"*N+. The reason for this is that there is no responsefrom the core network.

4fter sending a J*elocation reBuiredK message to core network to reBuest a ?'M resource7 the '"

*N+ starts a timer called T*(85+prep. When there is no response from the core network and the

timer epires7 a J*elocation cancelK with cause -alue JT*(85+prep epiry $;K is sent out o-er*4N40 to the core network from the '"*N+. It should be noted that the connection is still kept.

Falt Case 4

The &( sends a J/ando-er from &T*4N failureK message to &T*4N and7 the ratio of inter"

*4T hando-er attempts to ?'M where the &( returns to old channel per cell relation7 i.e.

or 7 is -eryhigh.

The reason for this fault might be a failure to access the ?'M cell. 4fter the &( recei-es

J/ando-er from &T*4N commandK7 it tries to access the target ?'M cell. If the attempt fails7

the &( sends a J/ando-er from &T*4N failureK message to &T*4N and returns to the oldchannel.

If the is -ery high7 the reason of the failure is due to

failure of connection setup on the ?'M side.

Falt Case 5

The number of inter"*4T hando-er attempts to ?'M where the resource allocation in the ?'M

network fails per cell relation7 i.e. pmNoOutIrat)oResour"eAllo"$ail 7is -ery high.

The reason can be no ?'M resources or no response from the core network.



Note= The counter pmNoOutIrat)oResour"eAllo"$ail is incremented one step when the core

network sends out a J*elocation preparation failureK or the timer T*(85+prep epires.

Falt Case ? dropped call drin' 8ando7er

)efinition=

From the dri-e test7 the following symptoms will be obser-ed=

• J**+ connection releaseK 8; message with unspecified reason is sent out from &T*4N

and then

• J**+ connection release completeK 8; message is sent to &T*4N and then• the connection drops.

These symptoms can be applied to the radio connection in connected mode7 i.e. either cell>)+/

or cell>F4+/.

The relocation o-erall $for hando-er timer or cell change timer epires=

In inter"*4T hando-er7 when the target ?'M cell has allocated resources for a new radio link7&T*4N sends an Jhando-er from &T*4N commandK message to the &( and starts the

relocation o-erall timer. If the target ?'M cell reports to &T*4N that the I*4T hando-er is

completed7 the timer will be stopped. 5therwise7 &T*4N waits for the timer to epire. 4fter theepiry7 &T*4N orders the &( to release the connection because &T*4N considers the

connection not enough good.

In inter"*4T cell change7 when &T*4N decides to eecute the inter"*4T cell change function7

&T*4N sends a Jcell change order from &T*4NK message to the &( and starts the cell changetimer. If the core network initiates the Iu release procedure7 the timer will be stopped. 5therwise7

&T*4N waits for the timer epiry. 4fter the epiry7 &T*4N orders the &( to release the

connection because &T*4N considers the connection not enough good.

Falt Case $? dropped call drin' 8ando7er 2

Measurement control failure=

In inter"*4T hando-er or cell change7 if the &( sends a Jmeasurement control failureK message

to &T*4N7 &T*4N considers that the &( will not measure on ordered neighbouring cells and

also not report on entering these cells. To a-oid that the &( runs into a cell and starts interfering7&T*4N orders the &( to release the connection.

Falt Case %

The (-ent ;a measurement report is not sent from the &( to &T*4N or the e-ent ;a

measurement report is sent to &T*4N7 but &T*4N does not recei-e it.



0rereBuisites=

3. The &( has started compressed mode to measure ?'M cells and recei-es the

measurement control from &T*4N to indicate the ?'M neighbouring cells.@. *ecei-ed (cANo of the best ser-ing cell in acti-e set is less than

;tranThresh3a<cno(scp) and;. 4 suitable ?'M cell is found and recei-ed *''I of that cell is larger than 6s&Thresh3a.

Note= The recei-ed *''I of the suitable ?'M cell can be measured by using ?'M carrierscanner or ?'M T(M'.

4.5.2.2 Soltions

Falt Case

'olution 3=

The engineer should optimise the ?'M network to lower the congestion7 e.g. add more T*s or

re"dimension the ?'M network. 5b-iously7 it is a cost" and time"consuming solution because

installation work is needed.

'olution @=

The 6s&0&ont-ropepeat can be increased so that the congested ?'M cell can be tried

more times for each access attempt. /owe-er7 it will gi-e a longer inter"*4T hando-er delay and

increases the probability of ha-ing pilot channel failure.

It should be noted that the 6s&0&ont-ropepeat is an *N+ parameter. That means changingit will affect the whole *N+.

Falt Case 2

No solution pro-ided.

Falt Case 3

No solution pro-ided.

Falt Case 4

The engineer should optimise the ?'M network to make the ?'M connection setup successful.

Falt Case 5



'ee solutions for Fault +ase 3 or ;.

Falt Case

0ossible solutions are=

• The connection setup fails when the &( is camping on the ?'M network. The engineershould optimise the ?'M network.

• The &( does not recei-e the Jhando-er from &T*4N commandK or Jcell change order

from &T*4NK e-en though &T*4N sends it out. The reason can be because of poorBuality in the downlink. 0lease read chapter D.3<.@ Fault +ases @;"@2.

Falt Case $

The reason is due to poor downlink Buality. 0lease read chapter D.3<.@ Fault +ases @;"@2.

Falt Case %

'olution 3=

0oor uplink Buality= please read chapter D.3<.@ Fault +ases 3L"@@.

'olution @=

Missing ?'M neighbouring cell= In the dri-e test7 the engineer can monitor the neighbouring cellwindow to check if the desired ?'M cell is included in the inter"*4T monitored set. The direct

solution is to add the desired cell into the neighbouring cell lists of the cells in the acti-e set.

/owe-er7 it should be noted that too many neighbouring cell relationships might slow down thesearch for the ?'M carriers.

'olution ;=

If &T*4N co-erage rapidly fades out7 e.g. outdoor to indoor7 the &( might not ha-e enough time

to mo-e the ?'M network. There are two possible cases=

• +ase 3= 4-erage ?'M *''I is high.









Figure D.;@ &T*4N co-erage rapidly fades and a-erage ?'M *''I is high.

• +ase @= ?'M *''I rapidly increases.

Figure D.;; &T*4N co-erage and ?'M *''I rapidly fades and increases respecti-ely.

3. For both cases7 &T*4N Thresh3a<cno(scp) should be increased so that it is far away from

H32d% and so that the e-ent7 i.e. e-ent ;a7 for the inter"*4T hando-er or cell change is triggeredearly.

For case @7 the 6s&Thresh3a can be decreased or a positi-e -alue can be gi-en to the

ndi7idal,set for the eternal ?'M cell.

It should be noted that &T*4N Thresh3a<cno(scp) and 6s&Thresh3a are *N+ parameters.That means changing them will affect the whole *N+.

@. The engineer can change the antenna configuration or re"locate the sites so that the cell

o-erlapping area becomes larger. 5b-iously7 it is a cost and time"consuming solution.

'olution D=

Too long ?'M neighbouring list= 4ccording to ;?00 standardiCation7 the maimum number of&( measured cells is ;@ for ?'M freBuencies. Therefore7 if the total number of cells in the



The load in the ?'M network increases due to too many inter"*4T hando-ers and cell changes.

4.5.3.2 Falt Cases

Falt Case

From the dri-e test7 the following symptoms are obser-ed=

• *ecei-ed (cANo of the pilot channel is less than ;tranThresh3a<cno(scp) and

• *ecei-ed *'+0 of the pilot channel is high enough to maintain the connection7 e.g. P"3<<d%m and

• )8 *''I is -ery high and

• Inter"*4T hando-er or cell change finally happens.

Falt Case 2

From the dri-e test7 the following symptoms are obser-ed=

• *ecei-ed (cANo of the pilot channel is less than ;tranThresh3a<cno(scp) and

• *ecei-ed *'+0 of the pilot channel is -ery low7 e.g. "3<<d%m and

• )8 *''I is -ery low and• Inter"*4T hando-er or cell change finally happens.

Falt Case 3

If &T*4N Thresh3a<cno(scp) is set too high7 the number of inter"*4T hando-ers or cellchange e-ents becomes larger.

Falt Case 4

If the inter"*4T search parameter S0TSearch is set to a too high positi-e -alue7 unnecessaryinter"*4T cell re"selections may be caused.

Falt Case 5


The &( sends a J+ell change order from &T*4N failureK message to &T*4N andAor

The ratio of inter"*4T cell change attempts to ?'M where the &( on dedicated channel returns

to old channel per cell relation7 i.e. 7 is -ery high.



The reason for this failure is because of failure to camp on the ?'M cell. 4fter the &( recei-es

J+ell change order from &T*4NK7 it tries to camp on the target ?'M cell. If the camping fails7the &( sends a J+ell change order from &T*4N failureK message to &T*4N and returns to the

old channel. The reason of the failure is due to failure of connection setup on the ?'M side.

4.5.3.3 Soltions

Falt Case

The reasons and solutions in this case are same as these for the pilot channel failure due to high

downlink interference. 0lease read chapter D.L.; Fault +ase 3";.

Note= The CPICH_Ec/No trigger to determine the pilot channel failure is H32d%. /owe-er7 theCPICH_Ec/No trigger to determine the inter"*4T mobility is ;tranThresh3a<cno(scp). 4nd

the CPICH_Ec/No trigger to determine for inter"*4T cell re"selection is =AalMin ES0TSearch.

Falt Case 2

The reasons and solutions in this case are same as these for the pilot channel failure due to out of pilot co-erage. 0lease read chapter D.L.; Fault +ase D"1.

Falt Case 3

The engineer should ad:ust &T*4N Thresh3a<cno(scp) to a lower -alue. /owe-er7 the

probability of ha-ing pilot channel failure becomes high.

It should be noted that &T*4N Thresh3a<cno(scp) is a *N+ parameter. +hanging it willaffect the whole *N+.

Note= The CPICH_Ec/No trigger to determine the pilot channel failure is H32d%. /owe-er7 the

CPICH_Ec/No trigger to determine the inter"*4T mobility is ;tranThresh3a<cno(scp). 4ndthe CPICH_Ec/No trigger to determine for inter"*4T cell re"selection is =AalMin E

S0TSearch.

Falt Case 4

The engineer should modify the S0TSearch to a suitable -alue7 e.g. Dd%.

Falt Case 5

The engineer should optimise the ?'M network to make the ?'M connection setup successful.

Back to Top









4.5.4 Co&pressed Mode pro#le&s

4.5.4. Falt Cases

Falt Case

The &( sends e-ent @d measurement report to &T*4N to reBuest the initiation of compressed

mode. %ut &T*4N does not send any J0hysical channel reconfigurationK message to the &(.

Falt Case 2

&T*4N sends the J0hysical channel reconfigurationK message to the &(7 but the &( does not

recei-e it.

Falt Case 3

The &( recei-es the J0hysical channel reconfigurationK message but it does not send out theJ0hysical channel reconfiguration completeK message to &T*4N.

Falt Case 4

The &( sends out the J0hysical channel reconfiguration completeK to &T*4N but &T*4N does

not recei-e it.

Falt Case 5

From the performance statistics7 the following symptoms will be obser-ed=

or or or is -ery

low.

Falt Case

/igh number in pmCmStop.

This can depend on Jtransmission gap pattern seBuences o-erlappingK. When the &( hasrecei-ed se-eral compressed mode transmission gap pattern seBuences from &T*4N the

configurations and se-eral of these patterns are simultaneously acti-e7 and the &( transmitsJ0hysical channel reconfiguration failureK message to &T*4N if these seBuences are illegally

o-erlapping. The counter pmCmStop is incremented one step.

Falt Case $





From the performance statistics7 it is found that more than ;<R of the users per cell are in

compressed mode7 i.e. . The system should be designed

so that not more than ;<R of all users are in compressed mode. 5therwise7 the capacity of thecell becomes -ery low.

Ma9i&& allo"ed percenta'e o the ;<s in co&pressed

&ode O ;<R

4.5.4.2 Soltions

Falt Case

The admission control blocks the new access for compressed mode.

The admission policies for the new access in compressed mode are downlink T power7

congestion e-ents and number of compressed mode users. The admission control checks if

• The cell transmits too high downlink T power. 0lease read chapter D.3<.@ Fault +ases D"L.

• There are too many compressed mode users. 0lease read chapter D.1.D.3 Fault +ase .

• There are too many congestion e-ents. 0lease read chapters D.@.@ and D.@.;.

Falt Case 2

4 possible reason for this fault is because of poor Buality in the downlink. 0lease read chapterD.3<.@ Fault +ases @;"@2.

Falt Case 3

4 possible reason for this fault is that the &( is not ready to prepare for acti-ation of the

compressed mode.

Falt Case 4

4 reason for this fault case can be because of poor Buality in the uplink. 0lease read chapter

D.3<.@ Fault +ases 3L"@@.

Falt Case 5

Failure in compressed mode attempt. When &T*4N sends out a J0hysical channelreconfigurationK message to the &(7 the counter for number of compressed mode attempts is

incremented one step. When &T*4N recei-es a J0hysical channel reconfiguration completeK


















Normally7 the siCes of the windows for inter"*4T e-ent detection7 i.e.

;sedFreAelThresh2<cno"sedFreAThresh2d<cno(scp) and

sedFreAThresh2d<cno(scp) " ;tranThresh3a<cno(scp) 7 are kept constant7 e.g. @d% or

;d%. What the engineer does is :ust to ad:ust the sedFreAThresh2d<cno(scp) to optimise the

number of users in the compressed mode. 0lease see Figure D.;D.

Figure D.;D Window siCes for inter"*4T e-ent detection

'olution D=

/igh ?'M thresholds for e-ent ;a=

If the ?'M threshold for e-ent ;a7 i.e. 6s&Thresh3a7 is too high7 many &(s stay in compressed

mode although their Bualities ha-e dropped lower than Thresh3a<cno(scp).The engineer can ad:ust the 6s&Thresh3a to the a-erage ?'M *''I -alue to reduce the number

of users in the compressed mode. /owe-er7 that will cause more users to make inter"*4T

hando-er or cell change and the load of the ?'M network will be increased. Furthermore7

6s&Thresh3a is an *N+ parameter. This means changing it will affect the whole *N+.

'olution 1=

8ow restriction on admission policy=

4 possible reason for causing many users in compressed mode is a too low restriction on

admission policy7 i.e. +ompMode4dm is set too large. The engineer can decrease the to limitmaimum possible number of connections in compressed mode.

4. Location 0rea and otin' 0rea





4.. ,7er7ie"

From the dri-e test7 many location area $84 and routing area $*4 updates7 i.e.

7 are found from obser-ing the 8; message in T(M'.

Back to Top

4..2 Falt Cases

Falt Case

'hort periodic 84 or *4 updating timers=

If the timer for periodic 84 or *4 updating7 i.e. T322 or T332 respecti-ely7 is too short7 many

location area or routing area updates might be caused.

*eason @

Many location areas or routing areas=

If there are too many location areas or routing areas in a network7 many location area or routingarea updates might be caused.

Back to Top

4..3 Soltions

Falt Case

The engineer should ad:ust the T322 and T332 timers to suitable -alues7 e.g. 3 hour.

Falt Case 2

The engineer should check if there are too many location areas or routing areas in a network7 e.g.

dri-ing along the *4 or 84 borders7 and merge the unnecessary location or routing areas intoeach other.

Back to Top















4.$.3.2 easons

If any of these formulas show higher -alues than what is epected7 a tuning of +hannel 'witching

can impro-e the performance. +hannel 'witching beha-iour depends among others on what &(sthere are in the network and what applications that are used. (ricssons recommended setting andhints how to tune are gi-en in +hannel 'witching.

For the F4+/ usage per cell formula7 a high -alue can also depend on admission control. 0lease

refer to chapter [email protected] to check this.

Back to Top

4.% -ilot channel pro#le&s

4.%. Deinitions

4.%.. -ilot Channel Failre

When the pilot channel signal Buality drops below H32 d%7 the rake recei-er does not work properly for channel estimation. If it drops further down to H3L d%7 the pilot channel is no longer

demodulated7 see Figure D.;1.















Figure D.;1 0ilot channel beha-ior

Note= The -alue H32 d% is obtained from field trials. It might be changed due to ongoing product

de-elopment. In fact7 the -alue is dependent on the performance of the &(. 'ome &(s mightha-e poor $good performance and the starting (cANo of ha-ing pilot channel failure will be high

$low.

pilot channel <c>/o J ?dB the ter& @pilot channel ailre is

sed in this doc&ent

4.%..2 -ilot -olltion

The definition of pilot pollution is that a too many pilots with similar Buality o-erlap in one

location. In order to a-oid pilot pollution7 following conditions should be fulfilled.

In idle or cell>F4+/ mode=

$3<

pilot>count U7 yV means number of pilots appearing within and including U yV range. It should

be noted that the units of the obser-ables in eBuation 3< are d%.

$33



Figure D.;2 +ell re"selection region

Notes=

3. The unit for the eportin'an'e# is <.1d%.

@. It is recommended that the pilot scanning results for the pilot pollution fulfill thefollowing=

-ercenta'e o sa&ples ha7in' pilot polltion in the pilot

scannin' shold #e X 3<R

;. The area ha-ing pilot pollution normally accompanies with high downlink interference.

This is because much recei-ed common channel powers from the o-erlapping cells areaccumulated in those areas.

D. In pre-ious discussion7 it is assumed that all o-erlapping cells ha-e hando-er relationships

with each other.

Back to Top

4.%.2 ,7er7ie"

0ilot channel problems is di-ided into the following 2 areas=

. -ilot channel ailre ? hi'h do"nlink intererence

The fault cases 3"; deal with this problem.

From the dri-e test7 the following symptoms will be obser-ed by using T(M'=

*ecei-ed (cANo of the pilot channel is less than H32d% and

*ecei-ed *'+0 of the pilot channel is high enough to maintain the connection7

e.g. P "3<<d%m and







)8 *''I is -ery high and

The connection finally drops.

0lease read chapter D.3;.

Note= If the inter"*4T mobility function is acti-ated7 i.e. Fdd6s&8,Spp O 37 andworks properly7 this problem should not happen

2. -ilot channel ailre ? ot o pilot co7era'e

The fault cases D"1 deals with this problem. From the dri-e test7 the following symptoms

will be obser-ed by using T(M'=

*ecei-ed (cANo of the pilot channel is less than H32d% and

*ecei-ed *'+0 of the pilot channel is -ery low7 e.g. "3<<d%m and

)8 *''I is -ery low and



Figure D.; (ample of out"of"pilot co-erage7 the obser-ation is from pilot scanning

Note= If inter"*4T mobility function is acti-ated7 i.e. Fdd6s&8,Spp O 37 and works

properly7 this problem should not happen.

3. -ilot channel ailre ? inter?0T &o#ility pro#le&

The fault cases 2"3< deals with this problem. The inter"*4T hando-er and cell changefunctions are acti-ated7 i.e. Fdd6s&8,Spp O 3. /owe-er7 from the dri-e test7 it is

found that the recei-ed (cANo of the pilot channel is less than H32d% and the connection

finally drops.

4. -ilot polltion

Fault case 33 deals with this problem.



ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204-5.html#4.8.3FC11%234.8.3FC11







5. ;plink and pilot co7era'e i&#alance

The fault cases 3@"32 deals with this problem. From the dri-e test7 the following

symptoms will be obser-ed by using T(M'=

*ecei-ed (cANo of the pilot channel is larger than H32d% and Transmitted &( power reaches to maimum allowed -alue and



6. ;plink and pilot co7era'e i&#alance

Fault case 3 deals with this problem. From the dri-e test7 the following symptom6s will

be obser-ed by using T(M' and &(T*=

The &( does not recei-e the paging signal sent out from &T*4N or )uring **+ connection establishment7 the &( does not recei-e the **+

connection setup message sent out from &T*4N or

)uring cell update7 the &( does not recei-e the cell update confirm message sent

out from &T*4N or

The &( does not recei-e any system information distribution message

Back to Top

4.%.3 Falt Cases

Falt Case no do&inant cell

There are many o-erlapping cells in the problem area. The recei-ed signal strengths of these

pilots are almost the same7 i.e. there is a high Fcch -alue. 0lease refer to +o-erage and +apacity

?uideline for the Fcch eBuation.








http://cdmweb.ericsson.se/WEBLINK/ViewDocs?DocumentName=17%2F1551-HSD10102%2F1&Revision=G












Figure D.;L (ample of many cells o-erlapping7 the obser-ation is from the pilot scanning.

Falt Case 2 do&inant intererer

4n undesired cell with -ery high signal strength is found in the problem area.

Figure D.;G (ample of the o-ershooting problem from the undesired cell7 the obser-ation isfrom the pilot scanning.

Falt Case 3 lo" #est ser7in' --ilot>-Tot

The recei-ed (cANo of the best ser-ing pilot channel is -ery low $near or less than H32d% e-en

though there is no other cell. It means the pilot power setting is not large enough to fulfill eisting

downlink load.

Figure D.D< (ample of too low best ser-ing 00ilotA0Tot7 the obser-ation is from the pilot

scanning.

Falt Case 4 lo" pilot channel po"er

+o-erage hole appears because the power of the pilot channel is set too low.



Falt Case 5 incorrect po"er &easre&ent de to TM0

5perators using TM4 ha-e to put in the following information into &T*4N in order to obtain

accurate &8 and )8 power measurements= &8 feeder attenuation7 )8 feeder attenuation7 &8TM4 gain7 )8 TM4 insertion loss and others. 5therwise7 all power measurements in &T*4N

will be messed up.

Falt Case i&proper inter?0T &o#ility ;T0/ para&eter settin's

• The sedFreAThresh2d<cno(scp) is less than or too close to H32d%. 4s a result7 the&( does not send e-ent @d measurement report to &T*4N to reBuest ?'M measurement

before pilot channel failure.

• &T*4N Thresh3a<cno(scp) is less than or too close to H32d%. 4s a result7 the criteria

for ?'M hando-er or cell change can be not fulfilled before pilot channel failure.

Figure D.D3 Improper inter"*4T mobility &T*4N parameter settings

Falt Case $ co&pressed &ode nction ailre

The &( has sent the e-ent @d measurement report to &T*4N to reBuest ?'M measurement.

/owe-er7 due to compressed mode function failure7 ?'M measurement cannot be set up and noe-ent ;a setup attached on measurement control is sent to the &(.

Falt Case % i&proper inter?0T &o#ility 6SM para&eter settin's

The 6s&Thresh3a is set too high. 4s a result7 the criteria for ?'M hando-er or cell change can

be not fulfilled before pilot channel failure.



Falt Case nter?0T &o#ility e7ent detection ailre


Falt Case 1 nter?0T nction ailre

0lease read chapters D.1.@.

Falt Case no do&inant cell

The reason is too many o-erlapping cells at an area due to poor cell planning7 i.e. the Fcch -alue is

high.7 please see +o-erage and +apacity ?uideline.

It should be noted that the below solutions are for the camping and high signaling load problems.

For high interference in )87 please read chapter D.L.; Fault +ase 3.

Falt Case 2 lar'e pilot channel po"er

The uplink and pilot co-erage are imbalanced because the pilot power of the cell is set too large.

Falt Case 3 hi'h ;< T9 po"er restriction

4nother possible reason is due to too high &( T power restriction7 i.e. too low -alue of

Ma9T9-o"er;l. Thus7 the &( T power is limited by this parameter setting.

Falt Case 4 lo" restriction in ;L con'estion control

+ongestion control can limit the recei-ed &8 *''I. If the parameters are set in too lowrestriction7 i.e. too high Con'7 the cell might be o-erloaded in uplink and the uplink co-erage

becomes smaller than the planned one.

Note= The cell being o-erloaded in uplink suffer from high own cell interference or high other

cells interference or both.

Falt Case 5 incorrect po"er &easre&ent de to TM0

5perators using TM4 ha-e to put in the following information into &T*4N in order to obtain

accurate &8 and )8 power measurements= &8 feeder attenuation7 )8 feeder attenuation7 &8

TM4 gain7 )8 TM4 insertion loss and others. 5therwise7 all power measurements in &T*4Nwill be messed up.

If the sum of all parameters for uplink antenna path is larger than the sum of the real -alues7 the

uplink *''I then will be under"estimated. The cell might ha-e been o-erloaded in uplink

howe-er7 the congestion control does not determine this. Therefore7 the uplink co-erage will besmaller than the planned one4n example is gi-en in table D.2.















Table D.2 4n eample to illustrate the incorrect estimation of &8 *''I

4 *ecei-ed &8 *''I at the reference power

point

"L<d%m

% *eal TM4 gain 3<d%

+ *eal uplink feeder loss ";d%) O 4E%E+ Measured &8 *''I at the *%' port ";d%m

( 0arameter for TM4 gain @<d%

F 0arameter for uplink feeder loss "3d%

? O )"("F +alculated &8 *''I sent from *%' to *N+ "G@d%m

Falt Case ;< in co&pressed &ode

When the &( is in uplink compressed mode and its T power reaches the maimum allowed

-alue7 the pilot power of the cell is set too large. 4s a result7 the compressed mode uplink and

pilot co-erage can be defined as imbalanced.

Falt Cases $ lo" co&&on channel po"ers

There is no power control on the common channels. For that reason7 the engineer has to carefully plan enough F4+/ power to fulfill the assumed downlink load. If mistake is done during the

power calculation or the real load of the downlink carrier is larger than the assumed le-el7 the


The information of power settings for common channels can be found in reference J+ommon

control channel guidelineK

Back to Top

4.%.4 Soltions

Falt Case

The most direct and effecti-e way to sol-e this problem is to increase the pilot channel power

-ri&aryCpich-o"er of the desired cell.

http://cdmweb.ericsson.se/WEBLINK/ViewDocs?DocumentName=63%2F1551-HSD10102%2F1&Revision=E










Figure D.D@ *esult of increasing the pilot power of the desired cell e.g. pilot ;.

The drawbacks of this solution are=

• )ue to une-en pilot power setting7 some &(s might no longer be connected to the

JclosestK cell with respect to the path loss. Then they transmit with high &( powers. 4s a

result7 the uplink interference le-el of the carrier is conseBuently increased. It means theuplink is not optimiCed and this phenomenon is named uplink near"far problem. It is

recommended that

H eportin'an'eaA@ X difference of the pilot power settings

of two neighboring cells X eportin'an'eaA@

It should be noted that the unit for the eportin'an'ea is <.1d%.

For eample7 if the eportin'an'ea is 27 i.e. ;d%7 the margin for pilot power modification is

eBual to J";d% X difference of the pilot power settings of two neighboring cells X ;d%. 0leaseread appendi % for the restrictions to modify the pilot channel power.

• In case the pilot power of a cell is increased7 the power of common channels in that cell

will simultaneously increase because their parameter settings are relati-e to the pilot

power -alue. 4t the same time7 the reBuired power for the downlink )0+/s in that cellalso increase. Finally7 the load of the cell becomes high and then cell blocking may

happen.

• The downlink interference le-el of the carrier will be higher.• The cell with higher pilot power will absorb more &(s from its ad:acent cells. Then the

load of the cell will be higher.

•

• 0ilot power changes may lead to uplink co-erage and pilot co-erage imbalance problems7 please read chapter D.L.; Fault +ases 3@"3 for details.

Falt Case 2





'olution 3=

The simplest solution to o-ercome this problem is to include the o-ershooting cell in the

neighboring cell list. This means the interferer now becomes a useful radio link.

Figure D.D; *esult of adding the o-ershooting cell into the neighboring cell list.

The drawbacks of solution 3 are=

• It creates more unnecessary hando-ers and ecessi-e numbers of &(s are in soft

hando-er.

• If the o-ershooting cell is physically far way to the problem area7 the hando-er seBuencemight be messed up after including it into the neighboring cell list.

• /ando-er e-ent detection in the &( becomes -ery slow if the list of the neighboring cells

is -ery long.

• 4dditional radio links can cause out of hardware resources in both interferer andinterfered cell.

• 4dditional radio links can cause cell blocking in both interferer and interfered cell.

'olution @=

4n alternati-e solution is to change the antenna configuration of the o-ershooting cell7 e.g. tiltingdown the antenna7 re"directing the antenna orientation7 or reducing the antenna height.

With this solution7 &8A)8 co-erage imbalance problems will not occur in the interferer because

both &8A)8 path losses are modified simultaneously. Moreo-er7 the interferer probably will

co-er fewer &(s7 and transmit a lower total downlink power. This means that it#s downlinkinterference contribution might be further decreased7 see Figure D.DD.



Figure D.DD Tilting down the antenna at the interfering site reduces downlink interference.

The drawbacks of solution @ are=

• Time and cost consumption are high.

• The desired co-erage of the interferer is modified. +o-erage holes might occur.,erification of the co-erage should be done again.

• Neighboring cells of the interferer will co-er a larger area and will thus absorb additional

&(s. The risk of high blocking rate therefore increases in these cells. Moreo-er7 due to

transmission of high T power7 they might become interferers if their co-erage is not wellconfined.

'olution ;=

The third possible solution is to decrease the -ri&aryCpich-o"er of the o-ershooting cell.

4fter decreasing the pilot power7 the total downlink power for the common channels of theinterferer decreases. When the pilot power is reduced7 the power of all other common channel

decreases simultaneously because their parameter settings are relati-e to the pilot power -alue.

Moreo-er7 the total )8 )0+/ T power of the interferer will probably decrease because the

interferer will co-er fewer &(s.



Figure D.D1 *educing the pilot power reduces downlink interference


• It is not a solution for long term. The pilot power reduction does not affect the physical

path loss. Therefore7 when the load of the interfering cell gradually increases7 theinterference issues will occur again at the same area as before.

• This solution is not suitable for a capacity limited interferer. The total transmission power

of the downlink control channels that is sa-ed by reducing the pilot power is used by new

)0+/s.• 8ike the problem in increasing pilot power7 the uplink is not optimiCed due to une-en

pilot power setting. It is recommended that

H eportin'an'eaA@ X difference of the pilot power settings

of two neighboring cells X eportin'an'eaA@

It should be noted that the unit for the *eporting*ange3a is <.1d%.


eBual to J";d% X difference of the pilot power settings of two neighbouring cells X ;d%. 0leaseread chapter D.3@ for the restrictions to modify the pilot channel power.

• When reducing the pilot power7 the downlink channel estimation in the &( is affected.

This influences the downlink Buality. In the end7 the &( might reBuest more power from

the base stations.• When the pilot power is reduced7 the maimum allowed )8 )+/ power decreases

simultaneously because this parameter setting is relati-e to the pilot power -alue. Then7

outage of the downlink )0+/ will be higher if the pilot power is reduced too much.0lease read chapter D.3@ for the restrictions to modify the pilot channel power.

• The desired co-erage of the interferer is modified. +o-erage holes might occur.

,erification of the co-erage should be done again.• Neighbouring cells of the interferer will co-er a larger area and will thus absorb

additional &(s. The risk of high blocking rate therefore increases in these cells.








Moreo-er7 due to transmission of high T power7 they might become interferers if their

co-erage is not well confined.

Falt Case 3

'olution ;a=

The best solution is to add a new site with Jgood co-erage controlK at the problematic area.

It is a cost" and time"consuming solution because installation work is needed. 4fter ha-ing a new

site7 the optimiCation engineers ha-e to -erify the co-erage once again to ensure that the co-erage

of the new site is well under control. J?ood co-erage controlK is etremely important in aW+)M4 system. The probability of interference problems can be minimiCed with a suitable

degree of o-erlapping.

Note= In T)M4 or F)M4 systems7 the problems due to poor co-erage control $ecessi-e

o-erlap can be hidden by freBuency planning.

'olution ;b=

4nother possible solution is to shift the downlink load of the problematic cell to its ad:acent cells.

0lease read chapter [email protected] for details.

'olution ;c=

It is an issue due to high total downlink T power. 0lease read chapter D.3<.@ Fault +ases D"L.

'olution ;d=

The direct but ineffecti-e solution is to increase the pilot channel power -ri&aryCpich-o"er of

the problematic cell. With high pilot power7 the common channel powers and the reBuired power

for the downlink )0+/s will be increased. Therefore7 the total transmission downlink power of

the cell will conseBuently increase. 4t the end7 the ratio of the 0 0ilotA0Tot does not increase much.0lease read chapter D.L.; Fault +ase 3 for the drawbacks after the pilot power is increased.

Falt Case 4

Soltion 4a*

The best solution is to add a new site at the problematic area. The drawbacks of adding new site

are same these for the chapter D.L.D Fault +ase ;7 solution ;a.

'olution Db=

4nother solution is to increase the pilot channel power -ri&aryCpich-o"er. The drawbacks are

the same as these for chapter D.L.D Fault +ase 3.












Falt Case 5

0lease refer to 90ower reference 0oint )efinition9 to sol-e this kind of problems.

Falt Case

The direct solution is to increase both sedFreAThresh2d<cno(scp) and

;tranThresh3a<cno(scp) so that they are far away from the JregionK in where the pilot

channel fails.

The change of these parameters will lead to more &(s in compressed mode and more inter"*4T

hando-er or cell changes. It might cause high load in the &T*4N cells because many users are incompressed mode7 and high congestion in ?'M network. Furthermore7 these parameters are *N+

parameters. that means changing them will affect all cells in that *N+.

Falt Case $

0lease read chapter D.1.D.

Falt Case %

The direct solution is to decrease 6s&Thresh3a to the a-erage *''I -alue of the ?'M carrier.

The change of this parameter will lead to more inter"*4T hando-er or cell changes and might

cause high congestion in the ?'M network. Furthermore7 this parameter is an *N+ parameter.

That means changing it will affect all cells in that *N+.

Falt Case


Falt Case 1

0lease read chapters D.1.@ and D.1.;.

Falt Case

'olution 33a=

The direct solution is to remo-e the cells o-erlapping by changing the antenna configurations orreducing pilot powers of the unwanted cells. /owe-er7 the change needs to in-ol-e many cells

otherwise7 the result will not be ob-ious.

The drawbacks of changing antenna configuration and reducing pilot power are respecti-ely

same as these for the solution @ and ; for Fault +ase @ in chapter D.L.D.

'olution 33b=










ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204-5.html#4.8.4FC2S2%234.8.4FC2S2









The most effecti-e solution is to increase the pilot channel power -ri&aryCpich-o"er of the

desired cell. The drawbacks are the same as these for Fault +ase 3 in chapter D.L.D.

'olution 33c=

For the pilot pollution in idle or cell>F4+/ mode7 the =,set2sn (C-C8 <c>/o) parameter ofthe desired cell can be increased to create a dominant cell.


• It might cause different borders in idleAcell>F4+/ and cell>)+/ modes. To sol-e this

problem7 the same -alue should be gi-en to the ndi7idal,set and =,set2sn

(C-C8 <c>/o).

• It might cause connection setup failure because &8 or )8 cannot transmit enough initial

power for the enlarged idle mode border.

Falt Case 2

When the uplink co-erage border $0*4+/ or )0+/ cannot reach the soft hando-er area

location7 the pilot co-erage is larger than the uplink co-erage. The only way to sol-e this problem

is to reduce the pilot power -ri&aryCpich-o"er. This modification will reduce the downlink

co-erage and pull back the soft hando-er area. Nothing can be done on the uplink side since &(T power is restricted by terminal design.

Figure D.D2 *educing the pilot power can rectify uplink"pilot co-erage imbalance.

The drawbacks of reducing pilot power are same as these for the solution ;7 Fault +ase @ inchapter G.D.

Falt Case 3

The Ma9T9-o"er;l should be set as the one used in dimensioning or cell planning. Foreample7 if the maimum &( T power is assumed to be @Dd%m for all &( classes in the

dimensioning7 the Ma9T9-o"er;l should be set to be @Dd%m.











The Ma9T9-o"er;l parameter will affect the cell re"selection procedures in idle mode. If it is

set too high7 the J0compensationK7 which is eBual to the maimum -alue of Jthe

Ma9T9-o"er;l " output power of the &( according to its classK and Cero7 becomes large and

the idle mode cell co-erage for some &( classes will then shrink.

Falt Case 4

Con' should be set to be the same as the -alue used in dimensioning or cell planning.

Falt Case 5

Information on how to obtain correct $or good enough power measurements is gi-en in 90owerreference 0oint )efinition9. The uniBue way to sol-e this problem is to correct these parameters

as the real ones. /owe-er7 it is a time consuming solution and difficult to measure the accurate

feeder loss and TM4 gain -alue.

Falt Case

The only way to sol-e this problem is to reduce the pilot power7 i.e. -ri&aryCpich-o"er. The

drawbacks of reducing the pilot power are same as these for the Fault +ase @7 solution ; in

chapter D.L.D.

Figure D.D *educing the pilot power can rectify uplink $in compressed mode"pilot co-erage

imbalance.

Falt Case $

Increasing the common channel power le-el can sol-e )8 ++/ and pilot co-erage imbalance problems. 0arameters for setting the power on the common channels are gi-en in Table D..

Note= 4ll )8 ++/ parameters are parameters per cell.

Table D. 0arameters for common channels













+ommon

channel

0arameter for power setting

%+/ #ch-o"er

'+/ pri&arySch-o"er7 secondarySch-o"er

F4+/ &a9Fach-o"er7 &a9Fach2-o"er

0+/ pch-o"er 0I+/ pich-o"er

4I+/ aich-o"er

The drawbacks of increasing the powers of the )8 common channels are increased )8interference in the carrier and increased load of the cell.

Back to Top

4. -o"er Control?apidly chan'in' radioen7iron&ent

4.. ,7er7ie"


• The &( rapidly mo-es into another radio en-ironment7 e.g. from indoor to outdoor.• *ecei-ed (cANo of the pilot channel is larger than H32d% and

• &( T power does not reach the maimum allowed -alue and• &8 %8(* of the radio connection increases and• The connection finally drops.

Back to Top

4..2 Falt Cases

Falt Case ;L oter loop po"er control pro#le&

If a cell co-ers se-eral di-erse radio en-ironments7 e.g. outdoor7 indoor7 tunnels etc.7 the outer

loop power control may not properly be able to adapt to the rapid en-ironment changes.

Back to Top

















4..3 Soltions

Falt Case

'olution 3=

The engineer should check if the regulation type for the uplink outer loop power controlalgorithm is set to JSumpK regulator7 i.e. ;l,terLoope'lator O 3. With the JSumpK

regulator7 the &8 'I* target is changed freBuently to follow the %8(* progression more closely.

The step to increase the 'I* target is large on the other hand7 the step is small for decreasing the'I* target. This regulator is good for rapid en-ironment changes.

Figure D.DL JSumpK regulator7 referred from +0I document

The drawbacks are=

• The &8 'I* target will fluctuate much. To reduce the unnecessary fluctuation7 the step

siCe of the &8 'I* target7 ;lSirStep should be gi-en a -ery small -alue.• In order to speed up the 'I* target con-ergence7 it is necessary that the initial 'I* target

is set below the assumed -alue instead of abo-e it since if the Buality is too good the

%8(* estimation takes longer time than if the Buality is :ust Jenough goodK.• ;l,terLoope'lator is an *N+ parameter. +hanging it will affect the whole *N+.

'olution @

If the uplink interference of the network is not high7 the step siCe of the &8 'I* target

;LSstep can be increased. Then the &8 'I* target can be changed Buicker to o-ercome thehigh %8(* situation.

The drawbacks are=





• The a-erage &8 'I* target will be higher and the &(s will transmit with higher power.

Then the uplink interference in the carrier is conseBuently increased.• ;lSirStep is an *N+ parameter. +hanging it will affect the whole *N+.

'olution ;

The last possible solution is to split the cell into se-eral cells.

Figure D.DG )edicated cells may co-er di-erse radio en-ironments

/owe-er7 cell split is a cost" and time"consuming solution because installation work is needed.

Back to Top

4.1 -o"er pro#le&s

4.1. ,7er7ie"

0ower problems are in this document di-ided into areas7 with their fault symptoms listed below.

3. /ot ll co7era'e e7en tho'h ll co7era'e is desi'ned or D-C8s

This area is co-ered by fault case 3.

From the dri-e test7 following symptoms will be obser-ed by using T(M' and &(T*=

*ecei-ed (cANo of the pilot channel is larger than H32d% and

Transmitted )8 code power reaches to the maimum allowed -alue and

The )8 %8(* of the connection is high and

The connection finally drops or switches down to the net lower data rate if the

radio bearer of the connection is 0'2DA;LD or 0'2DA3@L.











From the performance statistics7 many down"switching e-ents7 i.e.

pmChSwit"hP*%+P'!% and pmChSwit"hP'!%P(+ are -ery high7 are found for the )8)0+/s which are originally planned for full co-erage.

2. Dropped calls ll co7era'e /,T desi'ned or D-C8s

This area is co-ered by fault case @.

The 5perator may ha-e designed not full co-erage for 0'2DA;LD or 0'2DA3@L radio

bearers7 i.e. intended )8 )0+/ and pilot co-erage imbalance. When the connection inthese types reaches the co-erage border7 the channel switching function then switches it

down to the net lower bit rate radio bearer to maintain the connection.

The channel switching monitors the downlink transmitted code power of all radio links in

the acti-e set. 4 down"switch7 to the net lower bit rate radio bearer7 is reBuested if allradio links in the acti-e set use a transmitted code power close to the maimum allowed

code power.



Transmitted )8 code power reaches maimum allowed -alue and

The )8 %8(* of the connection is high and


3. nsicient recei7ed ;L D-C8 po"er

This area is co-ered by fault case ;.

From the dri-e test7 following symptoms will be obser-ed by using T(M' and &(T*=


&( T power does not reach the maimum allowed -alue and

&8 'I* target of the radio connection reaches the maimum allowed 'I* target

and

&8 %8(* of the radio connection increases and


4. 8i'h do"nlink T9 po"er

This area is co-ered by fault cases D"L. From the performance statistics7 it is found that

total downlink transmission power7 i.e. pmTransmittedCarrierPower is -ery high. In the

initial phase7 it is suggested that=

07era'e do"nlink T9 po"er (i.e. pmTransmittedCarrierPower )

shold #e X G<R o the planned &a9i&& allo"ed do"nlink T9

po"er










Figure D.1< Increasing the maimum allowed code power sol-es )8 )0+/ and pilot co-erage

imbalance.

Falt Case 2 do"nlink po"er drit

)uring softAsofter hando-er it is assumed that the downlink power of the in-ol-ed radio links arecoordinated. This coordination is done by starting the radio link at the correct power le-el and

then by recei-ing the same T0+ commands from the &(.

/owe-er7 the recei-ed T0+ commands at different *%'s will be affected with different errors

and conseBuently the downlink output power of the different radio links will start to drift and beuncoordinated between the *%'s. This phenomenon is defined as the downlink power drift.

Therefore7 if downlink power drift happens7 it is possible that not all radio links reach maimum

allowed code power e-en though the &( has been at the co-erage border. Finally7 the radio bearer cannot be switched down and the connection drops. 0lease see Figure D.13.



Figure D.13. (ample of downlink power drift

Falt Case 3 lo" &a9i&& allo"ed ;L S tar'et

The base station cannot recei-e sufficient power from the uplink dedicated physical channel if

S&a9 is set too low.



Figure D.1@ Maimum allowed 'I* target setting too low

Falt Case 4 &any sers in DL SF>2 co&pressed &ode

The power control increases downlink 'I* target in order to a-oid block errors during and after

the Jspreading factorA@K compressed frames. For that reason7 if there are many users in )8 'FA@compressed mode7 the total downlink transmission power is increased.

The counters for the number of attempted Asuccessful )8 compressed mode in 'FA@ method are

pmCmAttDlSf! and pmCmSu""DlSf!7 respecti-ely.

Note= Normally7 maimum allowed percentage for the number of users in compressed mode is

about ;<R.

Falt Case 5 &any sers in sot>soter hando7er

It is recommended that the system should be designed not ha-ing more than D<R of all users in

soft or softer hando-er. 5therwise7 the total downlink transmission power might become -ery

high.

Ma9i&& reco&&ended percenta'e o the ;<s in sot or

soter hando7er O D<R

Falt Case ne7en load distri#tion

/igh uplink *''I andAor high downlink T 0ower can be caused by une-en load distribution.






Falt case $ hi'h do"nlink traic in the net"ork

The number of the subscribers and traffic per user may grow up to a certain le-el as a result7 the

calculations in the early dimensioning are no longer -alid.

Falt Case % i&proper DL ad&ission thresholds

)8 admission policy mainly uses )8 power monitor and )8 4'( to control the )8 power

resource. /owe-er7 the )8 4'( is not considered to be useful for regular# admission control andthe )8 4'( admission threshold is normally set to pole capacity7 i.e. maimum allowed capacity

in the cell. This means only )8 power monitor is used to control the )8 power resource.

There are three downlink admission thresholds for )8 power monitor. They are -"r0d&-"r0d&,set and BeMar'inDl-"r.

BeMar'inDl-"r is used for ser-ice differentiation. It limits the number of new non"guaranteedaccesses. The sa-ed )8 power resource will be reser-ed for other traffic classes or setups.

Therefore7 the actual parameters to limit the maimum allowed downlink load are -"r0d& and

-"r0d&,set. If they are set too high7 i.e. low admission restriction7 the cell will allow

pro-iding more )8 power resources to accept high downlink load. In case the cell really has highdownlink load because of any reasons mentioned in chapter 33.@ Fault +ase D"7 the downlink of

the cell will be o-erloaded. 0lease see Figure D.1;.

Figure D.1; Improper downlink admission threshold settings






Falt Case &any sers in ;L SF>2 co&pressed &ode

0ower control increases the uplink 'I* target in order to a-oid block errors during and after the

Jspreading factorA@K compressed frames. For that reason7 if there are many users in &8 'FA@compressed mode7 the total uplink *''I is increased.

The counters for the number of attempted Asuccessful &8 compressed mode in 'FA@ method are

pmCmAttUlSf! and pmCmSu""UlSf!7 respecti-ely.

Note= Normally7 maimum allowed percentage for the number of users in compressed mode isabout ;<R.

Falt Case 1 ne7en load distri#tion

/igh uplink *''I andAor high downlink T 0ower can be caused by une-en load distribution.


Falt Case hi'h plink traic in the net"ork

The number of the subscriber and traffic per user may grow up to a certain le-el as a result7 the

calculations in the early dimensioning are no longer -alid.

Falt Case 2 hi'h &ini&& allo"ed ;L S tar'et

If S&in is set too high7 the a-erage uplink *''I in the system might be unnecessary high.

Falt Case 3 ? incorrect po"er &easre&ent de to TM0

For operators using TM47 they ha-e to input the following information into &T*4N in order toobtain accurate &8 and )8 power measurements7 e.g. uplink feeder attenuation7 downlink feederattenuation7 uplink TM4 gain7 downlink TM4 insertion loss7 etc. 5therwise7 all power

measurements and the algorithms in &T*4N will be messed up.

With wrong parameter settings7 the initial power setting on &8 )0++/ and 0*4+/ is o-er"

estimated and the &( will then transmit in high power. 4s a result7 the uplink of the cell iso-erloaded.





Falt Case 4 other cells intererence

If the path loss isolation of a cell is low7 for eample because the antenna is mounted at a too high

le-el7 the &(s in other cells might generate unnecessarily much uplink interference to it.

Falt Case 5 i&proper ;L ad&ission thresholds

&8 admission policy mainly uses &8 4'( to control the uplink resources in a cell.

Figure D.1D Illustration of the relationship between the policy parameters7 admission reBuest

parameters and the 4'( monitor for &8.

5b-iously7 the BeMar'in0se;l is used for ser-ice differentiation. It limits the number of new

non"guaranteed accesses. The sa-ed uplink resources will be reser-ed for other traffic classes orsetups.

0se;l0d&,set allows accepting more accesses from the guaranteed data rate users in

hando-er state. It should be noted that the &8 *''I is not increased by the new connections fromhando-er. For eample7 please see Figure D.117

%efore hando-er=

• &( 3 connects to cell 4 and its uplink signals are interfering both cell 4 and %.

• &( @ connects to cell 4 and its uplink signals are interfering both cell 4 and %. /owe-er7

&( @ generates more uplink interference to cell % than what &( 3 does. It is because the



&( @ has passed o-er the &8 path loss &8 noise rise balancing point and is causing

uplink near"far problem.

4fter hando-er=

•

&( 3 connects to both cell 4 and %. The T power of the &( 3 is controlled by cell 4 andits uplink signal is interfering both cell 4 and % with same amounts like before hando-er.

• &( @ connects to both cell 4 and %. The T power of the &( @ is controlled by cell %

because it has passed the &8 pathloss &8 noise rise balancing point. Thus7 the le-els ofthe uplink interference from the &( @ to cell 4 and % are lower.

Figure D.11 &8 *''I -ariation before and after hando-er.

It should be noted although that 0se;l0d&,set will not affect the &8 *''I le-el7 a higher

-alue will :ust consume more *4% resources.

Therefore7 the actual parameter to limit the maimum allowed uplink interference from the own

cell is 0se;l0d&. If this parameter is set too high7 i.e. low admission restriction is gi-en the cellwill allow pro-iding more &8 resources to accept the new accesses. When the cell really has

many new accesses7 the uplink of the cell might be loaded up by its own cells interference.

Falt Case i&proper ;L con'estion thresholds

&8 admission policy can limit the uplink interference from own cell by controlling the uplinkresources in the cell. /owe-er7 total uplink *''I includes not only own cell interference but also

other cells interference. Therefore7 e-en though 0se;l0d& is set properly7 other cells

interference still can cause high uplink *''I. )ue to this7 &8 congestion control is designed tolimit maimum allowed uplink *''I. 0lease see Figure D.12.



Figure D.12 &plink congestion control and admission control threshold settings

&8 congestion control has two congestion parameters7 Con' and ,set. If these parameters

are set too high7 the cell might allow higher &8 *''I. When the cell really suffers high othercells interference andAor &8 admission control does not work properly7 the uplink of the cell will

be o-erloaded.

It should be noted that the units for Con' and ,set are <.3d% and <.3d%m7 respecti-ely. If

the Con' is eBual to 3;<7 i.e. 3;d% and the ,set is eBual to @<7 i.e. @d%m7 it means that the

uplink congestion e-ent is triggered when the uplink noise le-el is larger than H33@ E 3; E @d%m.

Falt Case $ Coe9istence isse

The high uplink *''I can be because of a coeistence issue. The coeistence sources can beother carriers in the same W+)M4 network7 other W+)M4 networks or other cellular systems.

Falt Case % pilot channel ailre

If the recei-ed (cANo of the best ser-ing pilot in acti-e set is close to or less than H32d%7 it implies

the pilot channel almost fails and the performance of the channel estimation for the downlinkdedication channel becomes -ery poor.



)ue to worse downlink Buality7 the &( will stop transmitting7 i.e. 0&( O <7 and the Buality on

uplink conseBuently becomes poor.

Falt Case poor Aality in do"nlink

If the Buality on downlink is -ery poor7 the &( will stop transmitting i.e. 0&( O <7 and the Buality

on uplink conseBuently becomes poor.

Furthermore7 poor Buality in downlink might cause errors on the T0+. If the &( follows the

wrong T0+ pattern to ad:ust its transmission power7 the uplink Buality becomes poor.

Falt Case 21 ? plink and pilot co7era'e i&#alance

If the &( has transmitted maimum allowed &( transmission power7 i.e. 0&( O maimum7 the

reason for poor Buality in uplink is because of uplink and pilot channel imbalance.

Falt Case 2 insicient recei7ed ;L D-C8 po"er

4 possible reason for poor Buality in uplink is because of insufficient recei-ed &8 )0+/ power.

Falt Case 22 rapidly chan'in' radio en7iron&ent

4 possible reason for poor Buality in uplink is because of rapidly changing radio en-ironment.

Falt Case 23 pilot channel ailre

If the recei-ed (cANo of the best ser-ing pilot in acti-e set is close to or less than H32d%7 it impliesthe pilot channel almost fails and the performance of channel estimation for the downlink

dedicated channel becomes -ery poor and the downlink Buality conseBuently becomes poor.

Falt Case 24 trans&ittin' &a9 DL code po"er

The reason of ha-ing poor downlink Buality may be because the &( has reached the downlinkdedicated channel border.



Falt Case 25 poor Aality in plink

0oor Buality in uplink might cause errors on the T0+. If the *%' follows the wrong T0+ pattern

to ad:ust its transmission power7 the downlink Buality becomes poor.

Falt Case 2 rapidly chan'in' radio en7iron&ent

4 possible reason of causing poor Buality in downlink is because of rapidly changing radio

en-ironment.

Back to Top

4.1.3 Soltions

Falt Case

If a change of co-erage is needed the combination of the parameters &a9-"rMa97

inter-"rMa97 &in-"rMa97 &ini&&ate7 nterate and Ma9ate shall be tuned. Forfurther information7 see the +apacity Management +0I.

The drawbacks are=

• If the total )8 T power is already -ery high7 the change might lead to congestion drops

due to high peak to a-erage M+04 output ratio.• 4 single &( with high maimum )8 code power at the cell border might o-erload the

cell and then the whole cell will be blocked7 i.e. admission control denies the new

connections.

Falt Case 2

The engineer should change the method for downlink power control to JbalancingK7 i.e.Dl-cMethod O %484N+IN?7 because the etent of downlink power drift can be reduced

through the downlink power balancing procedure.

*N+ allocates a reference power to each *%'7 which in-ol-es in soft hando-er. The downlink power used by each radio link is periodically ad:usted in siCe to the offset between the power

used by the )0++/A)0)+/ and the reference power. The result of this is that the *%'6s power

le-els slowly con-erge. In this way7 the *%' power drift is reduced.









The reference power for the *%'s is calculated in the *N+. It is calculated as the a-erage of the

measured -alues for transmitted code power from all in-ol-ed radio links7 ecept the links thatare out of synchroniCation in the uplink.

Note= The Dl-cMethod is an *N+ parameter. +hanging it will affect the whole *N+.

Falt Case 3

In order to allow &(s to transmit with higher power7 the S&a9 should be set sufficiently high.

The drawbacks are=

• The &(s are allowed to transmit with higher power. This means they might cause higher

uplink interference to the ad:acent cells.

The S&a9 is an *N+ parameter. +hanging it will affect all cells in the *N+.

Falt Case 4

0lease read chapter D.1.D Fault +ase .

Falt Case 5

'olution 1a=

The simple solution is to remo-e some unnecessary neighbouring cell relationships. /owe-er7 the

engineer should carefully :ustify the usefulness of the relationship before deletion. 5therwise7

more connection drops and high downlink interference may happen due to missing hando-errelationship.

'olution 1b=

4nother possible solution is to modify the hando-er parameter settings7 e.g. Ma90cti7eSet7

eportin'an'ea7 eportin'an'e# and 8ysteresisc7 so that the number of &(s in soft orsofter hando-er is reduced. /owe-er7 they are *N+ parameters. +hanging them will affect the

whole *N+.

'olution 1c=

This solution is to limit the radio resources7 i.e. downlink T power and &8 4'( so that the newaccesses in hando-er are blocked. The parameters for this solution are -"r0d&,set and






0se;l0d&,set. 8owering these parameters can reduce the number of &(s in soft or softer

hando-er.

Falt Case


Falt Case $

'olution a=

The direct solution is to add new sites to reduce the high load problem. /owe-er7 it is a cost" and

time"consuming solution because installation work is needed.

'olution b=

4n alternati-e solution is to add a second W+)M4 carrier. 0lease read chapter [email protected].@ 'olution

D.

Falt Case %

The direct solution is to decrease the -"r0d& and -"r0d&,set -alues. /owe-er7 changingthen will affect the )8 capacity of the whole cell.

Falt Case

0lease read chapter D.1.D Fault +ase .

Falt Case 1

0lease read chapter [email protected].@ 'olution D.

Falt Case


ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204-1.html#4.2.6.2S4















'olution 33a=

The direct solution is to add new sites to reduce the high load problem. /owe-er7 it is a cost" and

time"consuming solution because installation work is needed.

'olution 33b=

4n alternati-e solution is to add a second W+)M4 carrier. 0lease read chapter [email protected].@ 'olution

D.

Falt Case 2

The direct solution is to lower the S&in to a suitable -alue. It should be noted that it is an*N+ parameter. +hanging it will affect the whole *N+.

Falt Case 3

0lease refer to 90ower reference 0oint )efinition9 to sol-e this kind of problems.

Note= In the calculation for the initial &8 )0++/ and 0*4+/ power7 path loss is estimated

from the downlink CPICH_RSCP measurement. Thus7 the result of the calculation will not becorrect e-en if the uplink parameters are set correctly.

Falt Case 4

The direct solution is to increase the uplink path loss between the interfered cell and the

interferer.

/owe-er7 in contrast to the downlink7 it is -ery difficult to identify the uplink interference source.

Therefore7 modifications are normally done on the interfered cell7 instead of on the interferer7 e.g.

by

•

Tilting down the interfered cell antenna7• *educing the antenna height of the interfered cell7

• +hanging the antenna orientation of the interfered cell7

• *eplacing the antenna at the interfered cell with an antenna with fewer side $or backlobes

The drawbacks are=










Falt Case 2

0lease read chapter 33.@ Fault +ase ;.

Falt Case 22


Falt Case 23

0lease read chapters D.L.; Fault +ases 3"3< for solutions.

Falt Case 24

0lease read D.3<.@ Fault +ase 3 and @ for solutions.

Falt Case 25


Falt Case 2


4. ntererence ro& other cells

4.. Do"nlink

The simplest way to estimate the downlink interference le-el and to identify the sources of

interference is to use a pilot scanner which can pro-ide U RSSI V $#7 U E c /N oVCPICH and U RSCP VCPICH

measurements. 4fter obtaining the measurements7 there are two approaches to analyse them H the

Fcch approach and the statistical approach.

Fcch approach





















Note= )etailed Fcch definition and applications can be found in 9*adio Network +haracteriCation

?uideline9.

The formula of Fcch is=

$3;

If the Fcch -alue at a location is -ery high7 it means the recei-ed total pilot channel powers and the

recei-ed total common channel powers at that area are accumulated -ery high. Therefore7 the

probability of ha-ing downlink interference problems is -ery high.

In the initial deployment7 the degree of cell o-erlap is probably not high. Therefore7 it can beassumed that the maimum allowed Fcch -alue is eBual to ;. It is about that @<R of the maimum

allowed total downlink interference is from all downlink common channels7 please read 9*adio

Network +haracteriCation ?uideline9 for detail.

Ma9i&& allo"ed $ ""h O ;

Statistical approach

The theoretical and practical approaches as described abo-e are applied to the geographical area

where the problem appears. For a single $or entire cell7 a statistical approach can be employed7using statistical counters in *4N5'=

• Find out all CPICH_RSCP measurement sets with the tested cell as best cell. This is

called Jhighest CPICH_RSCP K.

• +alculate the +0I+/ path loss #CPICH of all pilots in each measurement set separately by #CPICH O U-ri&ary C-C8 po"erA3<VACPICH_RSCP

• +alculate the interference contributions of all pilots in each measurement sets separately

by I pilots O U pmTransmittedCarrierPower VA #CPICH .

• 4t different locations7 the total )8 T power of the cell is different. Instead of calculating

the total or a-erage interference contribution7 the maimum possible interference

contribution of a cell can be employed=

I max O U&a9 Trans&ission -o"erA3<VA #CPICH .Thus7 the worst situation is calculated.

• 'um up the interference contributions from each cells from all measurement sets anddi-ide the sum by the total number of locations7 to obtain an a-erage $of the worst

interference contributions from each cells.

• 'um up the pathloss from each cell from all measurement sets and di-ide the sum by thetotal number of locations7 to obtain an a-erage path loss from each cell.











• )etermine the interference source. The simplest way to identify the interference source is

to check whether the strong interference source is in the cell neighbouring cell list7 and ifso7 whether it is necessary there. If both answers are no7 this cell should be remo-ed as an

interferer.

Figure D.1 (ample of the statistical approach H interference contribution

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4..2 ;plink

&nlike the downlink7 there is no simple way to determine uplink other cell interference. It is

impossible to distinguish the interference from own cell and from other cells. 5ne indicator ofother to own cell interference in uplink is deri-ed below. This indicator is used as a rough

indication of how much the combined interference from other cells and the noise floor contribute

to the total uplink interference.

%efore epressing this indicator7 let us repeat the definitions of uplink 4'( for a radio link. The

air speech eBui-alent for a )+/7 ASE $CH is=







$3D

where

t!s)lex)act $c is the approimation of the acti-ity factor of the )+/.

Therefore7 the uplink 4'( for the speech )+/ is eBual to 3. The uplink 4'(s for the )+/s are=

Table L. 0re"calculated uplink 4'( -alues of the ser-ice

Ser7ices ;L 0S<

'tand"alone 3;.2A3;.2kbps '*%s for )++/ @.@

+on-ersationalAspeech 3@.@kbps *% E ;.Dkbps '*%s for)++/

3.2

+on-ersational +'2DA2D *% E '*%s on )0)+/A)0+/ 33.3

'treaming 1.2kbps +' *% E ;.Dkbps '*%s for )++/ .@

Interacti-e or background 0'2DA2D *% E ;.Dkbps '*%s on

)0)+/A)0+/

L.;

Interacti-e or background 0'2DA3@L *% E ;.Dkbps '*%s on

)++/

L.;

Interacti-e or background 0'2DA;LD *% E ;.Dkbps '*%s on

)++/

L.;

+on-ersationalAspeech *% E Interacti-e or background

0'2DA2D *% E ;.Dkbps '*%s

G.;

The total uplink 4'( of a cell can be thought as the total number speech users in the cell.

4fter re-iewing the definition of uplink 4'(7 let us consider the uplink SIR speecof a speech user7

who is sub:ect to power control=

$31

where the uplink recei-ed power P speec of that speech user is=

$32



Thus7 the total uplink own cell interference from all users being sub:ect to power control can be

epressed as=

$3

'ince

$3L

where N is the base station noise floor. The uplink non"own cell interference indicator is finally

epressed as=

$3G

The -alues for the eBuation -ariables can be obtained according to Table G.

Table G. 5bser-ability of the -ariables

:aria#le ,#ser7a#ility o the 7aria#le

ASE "# U pmSumOfSampAseUl V>U pmNoOfSampAseUl V

SIR speec 'imulated -alues 90ower settings for +ommon+hannels9

A) *oice <.1

It should be noted this uplink non"own cell interference indicator is based on the 4'( definitionin system release 0@ and some theoretical assumptions. If the 4'( definition or the assumptions

are changed7 this indicator will no longer be -alid.

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4.2 Modiication o the pilot po"er

4.2. ;plink non? opti&ised

Modification of pilot power is a common solution for most of the optimisation issues7 e.g. pilot

pollution7 high downlink interference7 une-en traffic distribution7 etc.














/owe-er7 when the power of pilot power setting is changed7 ecessi-e uplink interference is

probably generated to the cell with lower pilot power setting. This is because of the uplink near"far problem.

Figure D.1L *elationship between soft hando-er area and uplink pathlossnoise rise when the

pilot power settings in cell 4 and % are different.

In Figure D.1L7 the pilot power settings in cell 4 and % are different. Therefore7 the path loss noise rise balancing point between cell 4 and % are outside the soft hando-er area. When a &(mo-es from cell 4 to cell %7 it will transmit more and more power until it reaches the soft

hando-er area. &plink interference to cell % and other neighbouring cells will then be increased.


3. &( T power is proportional to min $path loss noise rise7 in linear7 please see eBuation

@;. &nder power control7 the -ariation of the &( T power will follow the red line in the

Figure D.1L.

@. )uring dri-e test under this near"far problem7 &( will eperience rapid T power dropwhen it mo-es from cell 4 to cell %.

;. Near to soft hando-er area border7 &( has to transmit etra T power in order to maintainthe connection. It does not necessarily lead to uplink connection drops7 but it might becritical if the &( doesn#t ha-e enough room to increase its T power. 8ack of &( T

power can also be interpreted that &8 power resource is not optimised.

D. 8ike Figure D.1G7 the difference of the pilot power settings of cell 4 and % should berestricted so that the balancing point of the path loss noise rise is in the soft hando-er

area and the -ariation of the &( T power follows the blue line.

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204-7.html#EQ4.23%23EQ4.23







I "# A is the uplink noise rise in the cell 4.

I "# + is the uplink noise rise in the cell %.

# A is the path loss from the cell 4 to the &(.

# + is the path loss from the cell % to the &(.

P Pilot A

is the pilot power setting in cell 4. P Pilot

+ is the pilot power setting in cell %.

R,a is the eportin'an'ea A@.

R,b is the eportin'an'e# A@.

It should be noted that the units for both eportin'an'ea and eportin'an'e# parametersare <.1d%. It means that if the eportin'an'ea is 27 the * 3a is eBual to ;d%.

Then7

$@3

4s a result7

$@@

where

P Pilot is the pilot power difference between cell 4 and %7 i.e. P Pilot A " P Pilot

+.

I "# is the noise rise difference between cell 4 and %7 i.e. I "# A- I "#

+.

Normally7 if the difference of the pilot power settings of two neighbouring cells is not -ery large7

the noise rise difference between the cells is -ery little7 the margin for modifying the pilot powers

of two neighbouring cells is like=

U 0ilot power difference of two neighbouring cells V Xeportin'an'ea A@

It should be noted that the unit for eportin'an'ea is <.1d%. It means that if the

eportin'an'ea is 27 the * 3a is eBual to ;d%.


eBual to



$@;

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4.2.3 <9a&ple

For instance7 the eportin'an'ea is 27 i.e. ;d%. 4n eample of the hando-er relationships and

their pilot power settings are=

Table 3<. (ample

Cell na&e and its

pilot po"er

/ei'h#orin' cell

na&e and its pilot

po"er

-ilot po"er

dierence

+ell 47 ;<d%m +ell %7 @d%m ;d% 5Q

+ell 47 ;<d%m +ell +7 ;;d%m ;d% 5Q

+ell 47 ;<d%m +ell )7 @Ld%m @d% 5Q

+ell %7 @d%m +ell +7 ;;d%m 2d% /,K

+ell %7 @d%m +ell )7 @Ld%m 3d% 5Q

+ell +7 ;;d%m +ell )7 @Ld%m 1d% /,K

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4.2.4 -lannin' isses

The pre-ious eample shows that too many neighbouring cell relationships will lower the JroomK

for pilot power modification. Therefore7 as a W+)M4 planning engineer7 it is necessary to

planAoptimise=

• 'ufficient number of cell o-erlapping $not too many or too less• 'ufficient number of Ncell relationships $not too many or too less

• Not too big difference of uplink noise rise between Ncells.

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4.3 So&e drop cases in dri7e test















'ome connection drop cases can be obser-ed in dri-e tests. Figure D.2< shows how the measured

signals can -ary in the different drop scenarios.



• &plink )0+/ performance is dependent on the %8(* target setting for the uplink. If the

%8(* target is set to a low -alue7 the uplink )0+/ co-erage will decrease and the &(sin that cell will introduce more uplink interference to other cells. 5n the other hand7 if the

target is set to a high -alue7 poor Buality $e.g. ecessi-e %8(* or lower uplink

throughput might occur.•

&plink )0+/ co-erage -aries with the load. /owe-er7 the soft hando-er area does not.Therefore7 the main task in uplink optimisation is to make sure that the uplink )0+/ can

co-er the entire soft hando-er area. 5therwise7 connection drop or hando-er failure might

occur7 see Figure D.23.

Figure D.23 Illustration of why connection drop or hando-er failure can occur if the &8 $or )8co-erage does not etend o-er the entire soft hando-er area

Do"nlink dedicated physical channel

The recei-ed signal"to"interference ratio7 U'I*Vrecei*e' on the downlink )0+/7 is=

$@2

where

P $PCH%

is the transmitted power on the downlink )0+/ in cell

.

P Tot% is the total transmitted power in cell

P Sc%

is the transmitted synchroniCation channel power in

cell

# is the path loss between cell k and &(

3 is the orthogonality factor in cell



N "E is the &( noise floor

AS

is the number of radio links of the &( being in soft$er

hando-er. If &( is not in soft$er hando-er7 AS is eBualto 3.

4ccording to the balancing feature in the downlink power control algorithm7 P $PCH% /P Pilot% is aconstant for a radio connection. Therefore7

$@

The reBuired downlink )0+/ power P Re0_$PCH% for cell to fulfill reBuired target U'I*V tar1et is=

$@L

These downlink )0+/ eBuations ha-e se-eral important conseBuences related to optimisation.

• The recei-ed downlink )0+/ signal strengths from the different cells are the same at the

cell border. It is the reBuirement in the downlink power control.• For a radio connection7 the radio link from a cell with larger pilot channel power will

transmit larger downlink )0+/ power.

• If the recei-ed Buality cannot reach the target7 the maimum allowed downlink )0+/

power could be ad:usted to a higher -alue. $The corresponding problem in the uplinkcannot be sol-ed in the same way7 because &( T power is restricted by terminal design.

• )ownlink )0+/ performance is affected by the recei-ed downlink powers from all cells

in the system7 i.e. downlink *''I. The maimum allowed downlink T power of a cellcould be limited by the capacity management function. This means that the maimum

possible interference contribution to downlink *''I in a cell can be controlled.• The performance is dependent on the %8(* target setting for the downlink. When the

%8(* target is set to a low -alue7 the total downlink T power of a cell will increase7 because the downlink )0+/ power for each user will increase in an attempt to fulfil the

high Buality reBuirement. 5n the other hand7 if the %8(* target is set to a high -alue7

poor Buality $e.g. ecessi-e %8(* or lower downlink throughput might occur.• )ownlink )0+/ co-erage -aries with the load but the soft hando-er area does not.

Therefore7 the main task in downlink optimisation is to make sure that the downlink



)0+/ can co-er the entire whole soft hando-er area. 5therwise7 connection drop or

hando-er failure might occur7 see Figure D.23.

5 adio isses

This chapter will try to show some useful information to help the tuning acti-ity and eplain

problem issues.

5. /ei'h#or Cell -lan e7ie"

!hy re7isit the nei'h#or plan

The network we normally looking into is changing7 growing or the integrationAconfiguration is

still ongoing. *eparenting of Node"%6s and tilting of antenna6s are the main reason that theneighbour cell plan has to be re-iewed. The maimum configurable number of $intra freBuency

neighbours is ;@ $in [email protected] howe-er7 preferably the length should not eceed @3 neighbours$neighbour list truncation. /igher numbers should be a-oided.

The neighbour plan is ne-er optimal

• *edundant neighbours

" J?et caughtK on a wrong neighbour and drop

" Neighbour list truncation $and potentially drop• Missing neighbours

" +an pro-oke a drop call

The general seBuence of operations used for both neighbour cell additions and remo-als isillustrated in the following steps=

The main inputs are the implemented Neighbour $N% plan7 a measured N% plan7 and missingneighbours disco-ered during the analysis of dropped and blocked calls $i.e. drop"causing

neighbours. The measured neighbour plan can either arri-e from the 'canner $idle mode

detection or from the &( $connected mode detection as described below. The measured andimplemented N% plans are first compared and grouped into three sets=

• +onfirmed set $i.e.7 neighbour relation member of implemented and detected.

• +andidate for remo-al.

• +andidate for addition $i.e.7 neighbour relation has been detected but is not implemented.

The candidates for additionAremo-al are net analysed before additionAremo-al. This is importantin order to a-oid adding -ery distant cells as neighbours $in which case a tilt may be more

appropriate and not to blindly remo-e a neighbour $which7 for instance7 may not ha-e been

measured due to the route dri-en. 5nce a decision has been made7 the neighbour isaddedAremo-ed and in some situations monitored $especially with neighbour remo-als.

ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204-7.html#FG4.61%23FG4.61





ftp://ftp.ruc.eei.ericsson.se/rncplm/eeifguz_web/RncPLM_P3/Documents/GuideLines_Helper_TipsAndTricks/Gecko/mw1PA204-7.html#FG4.61%23FG4.61






. -re?processin'

2. Detailed analysis o candidates or addition>re&o7al

Detectin' /ei'h#or elations ro& Scanner Measre&ents

The 'canner measurements can be used to identify possible neighbours. To deri-e such

candidates we ha-e used )esk+at. The methodology is to identify all mutual '+ (cANo within acertain hysteresis $e.g.7 2d% used for addition. The hysteresis used is greater than

*eporting*ange3a $threshold for N% addition7 and therefore many N% candidates will be

measured. It is important to care!ull analse possible N+ relations on a map an' 'etermine te

most use!ul can'i'ates.



Detection o /ei'h#or elations ro& ;< Measre&ents

The Motorola 4L;1 reports )etected Neighbours $)N. This &( feature can be used to identify

new N% relations since a )N is one7 which has not been ordered for measurements by &T*4N7and therefore is a possible candidate in most situations. In some situations the )N is already

defined H which can be due to N% list truncation or due to delays of the measurement controlmessages sent by &T*4N in order to instruct the &( to measure on the corresponding neighbour.The &( will report many neighbours but filtering is needed in order to deri-e useful candidates.

For instance7 if 4'U3V +0I+/ (cANo is H@@d% and )NU3V +0I+/ (cANo is H3Ld% these are not

serious neighbour candidates because the hand"o-er is not likely to be successful at H@@d% e-en

though the )N is Dd% better. In order to identify the most important missing neighbourcandidates7 we ha-e used the following filter=

4'U3V P 4'>T/ [ )NU3V P )N>T/ [ 4'U3V")NU3V )(8T4>T/

Where 4'U3V is the strongest radio link in the 4' $4cti-e 'et and )NU3V is the strongest )N7

and finally 4'>T/7 )N>T/7 and )(8T4>T/ are filter coefficients. 5e stress tat allcan'i'ates are alas analse' b inspection on a map be!ore actions are taen.

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5.2 Tiltin'

The o-er"shooting cells ha-e mainly been identified during the N% plan re-iew7 where cells "

otherwise -ery far apart " ha-e demonstrated to be possible N% candidates. In such situations7adding the affected cells as neighbours may not be a sound solution. For instance7 if two cells

appear to be neighbour candidates7 but the cells are -ery far apart7 the best solution is probably to

introduce down"tilts to one of the in-ol-ed cells rather than adding the cells as neighbours withthe inherent risk of pro-oking neighbour list truncation and dropped calls.

Methodolo'y

The method used is a three"step process=

3. Identify candidates for down"tilt.

@. 4nalyse each candidate and decide for new tilt $in corporation with the local engineers.;. Monitor and back"off if reBuired.

The inputs to 'tep 3 ha-e been the cells that ha-e been found during the neighbour re-iew ascells with neighbour candidates of distant cells that shall not normally be considered as an

ob-ious neighbour.

In 'tep @ each candidate has carefully been analysed by studying the footprint of the ob:ecti-e

cell7 the general *F co-erage in the affected area7 and the +0I+/ interference in the affected

area.









In 'tep ; the before"and"after co-erage and interference in the -icinity of the cell has been

studied. If remarkable degradations ha-e been disco-ered7 the tilt is re-ersed to the original or anintermediate setting may ha-e been used.

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5.3 C-C8 -o"er 0dEst&ents

The recommended margin between +0I+/ power $primary+pich0ower and Mat0ower)l is

3<d%. From eperiments7 a power margin of Gd% must be a-ailable in order to pro-idesatisfactory 0' performance. Yet the +0I+/ power cannot be lowered arbitrarily since this will

reduce co-erage and perhaps more importantly introduce uplink interference because of

misalignment between uplink and downlink hando-er regions $power imbalance. It isrecommended not to ha-e a power misalignment between facing cells of more than

*eporting*ange3aA@. This rule is guiding and can be relaed in situations where cells are not

directly facing.



