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Drive Test/RF Optimization/RF Planning

By: -Faisal Khan

(RF Engineer)

ontents:

!"# Drive Test (TE#" $%&%' !EE* PROBE + ,"""T,T .%'

#,PFO$% #O# 0%1)

.) nstallation o2 TE#" $%&%'

1) ntro345tion to Drive Test an3 Types o2 Drive Test ("FT l4ster et5)

') Drive Test Parameters an3 ,nalysis

0) 6eri2ying 5l4tter type (4r7an s474r7an r4ral et5%)

) omplete 8or9ing o2 TE#" $%&'

) Physi5al 6eri2i5ation + Pre an3 Post Drive

;) on2ig4ration o2 the Tems Kit 2or . 1 ' 0 #o7ile + <o= to 3rive (6oi5e >3ata)

=ith . 1 ' an3 0 mo7ile

$) ?og File ,nalysis

@) <an3o22 iss4es 34ring 3rive test

.&) Operation o2 Tools #O# 0%1 #ap n2o $%

..) Preparing themati5 maps o2 RA ?evel RA 4ality an3 " et5%

.1) B" Drive an3 "ol4tions + 4stomer omplains

.') 8or9ing o2 !EE* Pro7e an3 ,ssistant .%'

.0) Drive Test ntervie= 4estions%

!"# ET8ORK OPT#C,TO:-

.) ntro345tion to KP (T</"D< DROP <O"R "D</T< ongestion

"D</T< Blo59ing "D</T< ,llo5ation 2ail4re "D</T< ,ssignment

2ail4re%)

1) Per2orman5e ,nalysis/KP ,nalysis

') Eri5sson KP an3 Optimization

0) o9ia KP an3 Optimization

!"# P?,!:-

.) B< Planning

1) <" an3 #,O Planning') T< or TR* Planning



D#, Drive Test + Optimization:

.) nstallation O2 D#, Drive Test Tool(,(D#, et=or9 ,nalyzer) +

T(D#, et=or9 Testing) )

1) Parameters o2 D#, Drive Test( 6oi5e + E6DO)') ,nalysis O2 the Parameters

0) omplete 8or9ing o2 the Tool) D#, Optimization

Drive Test Parameters:-



4rrent hannel Parameters:

1. Time: It is system time of computer.2. Cell name: It displays the name of the sector which is servingaccording to the cell le that is loaded in TEMS.3. CGI: It stands for the Cell Gloal Identity which is uni!ue forevery sector of the site. It consists of MCC" M#C" $%C" and CI.MCC: Moile Country Code & ' ((( M#C: Moile #etwor) Code & '(( $%C: $ocation %rea Code & *+,,-, CI: Cell Identity & ' +,,-,4. Cell GPRS Support: Tells sector is having G/S or not. 0aluesare 1es or #o.5. Band: It tells in which 2re!. 3and moile is operating e.g. GSM(&&4 56&&.6. BCCH ARC!: It tells y which 3CC7 is the moile station

getting served.". TCH ARC!: 8n which Tra9c 2re!. call is going on.#. BSIC 3ase Station Identity Code;: It is comination of #etwor)Color Code #CC; & ' <; = 3ase Station Color Code 3CC; & ' <;"e.g. +>. It is decoded y moile on every Synchroni?ation ChannelMessage.

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9. Mode: It is shows in which state is moile operating" Idle"@edicated = ac)et.1$. Time %lot: 8n which time slot of current TC7 call is going on.0i?. time slot #o. of T/A.

11. C&annel T'pe: Type of channel moile is getting now. $i)e3CC7 4 S@CC746 B S%CC74C6 or C3C7 4 TC742 B2%CC742BS%CC742.12. C&annel Mode: Shows mode of coding li)e Speech 2ull /ateof 7alf /ate.13. Spee(& Code() It shows 2/ for 2ull /ate" 7/ for 7alf /ate =E2/ for Enhanced 2ull /ate.14. Cip&erin* Al*orit&m: It shows ciphering algorithm used ythe system to protect data for privacy. E.g. Cipher y %,4>.15. Su+ C&annel !um+er: It is displayed at a time when

moile is on dedicated mode at time of call setup when it isgetting S@CC7 at that time it shows which S@CC7 it is getting outof 6 availale" e.g. >.16. Hoppin* C&annel) It shows that current sector is havinghopping feature or not. 0alue is 1es or #o.1". Hoppin* re,uen(ie%: It displays no. of fre!. on whichmoile is allowed to hop. 0i?. M% $ist for hopping of that sector.1#. Mo+ile Allo(ation Inde- /%et 0MAI: It is thenumer which tells from which fre!. from given M% list for sector

hopping has to e started. E.g. & means sector will start from rstfre!. to hop.1. Hoppin* Se,uen(e !um+er 0HS!: Indicates se!uence inwhich fre!uencies are allowed to hop from the M% $ist. &* +-. & forCyclic 7opping"5 ' +- random hopping se!uences.

Radio Parameter%)



1 R-e) /eceiving level in terms of d3m that moile isreceiving from the site. /ange of *-& d3m to *55&d3m.2 R-ual) uality of voice which is measured on asis of 3E/./ange of /Dual & *<.3 7R) 2rame Erasure /ate it represents the percentage offrames eing dropped due to high numer of non*corrected iterrors in the frame. It is indication of voice !uality in networ).

4 B7R A(tual: /atio of the numer of it errors to the totalnumer of its transmitted in a given time interval. 3E/ is ameasure for the voice !uality in networ).. @epending on 3E//Dual is measured. E.g." 3E/ & to &.> corresponds to /Dual&. MaD. 3E/ countale and useful is up to 5>.6 whichcorresponds to /Dual of maD. <.5 SI) SI is a more sophisticated measure which is dedicatedto reFecting the !uality of the speech as opposed to radioenvironment conditions;. This means that when optimi?ing the

speech !uality in your networ)" SI is the est criterion to use.SI is updated at &., s intervals. It is computed on asis of 3E/and 2E/. 2or E2/ -&" 2/ ' >5 = 7/ ' 5< are respectively idealvalues.6 C8I: The carrier*over*interference ratio is the ratio etween thesignal strength of the current serving cell andthe signal strength of undesired interfering; signal components.It should e at least (." MS Po9er Control eel: @isplays range of powercontrol from & to 6 depending upon networ) design. E.g. & meansno power control and 5 means level that is dened y operatorvi?. > d3m less acc. to %irtel.# :T;) @iscontinuous transmission @TA; is a mechanismallowing the radio transmitter to e switched oH during speechpauses. This feature reduces the power consumption of thetransmitter" which is important for MSs" and decreases the overall






interference level on the radio channels aHecting the capacity ofthe networ). TA: 0alue that the ase station calculates from access urstsand sends to the moile station MS; enaling the MS to

advance the timing of its transmissions to the 3S so as tocompensate for propagation delay. 0alue of & means MS in radiusof ,,&mt. 2rom 3TS.1$; R Timeout Counter 0Cur) This parameter denes themaDimum value of the radio lin) counter eDpressed in S%CC7loc)s. /ange of ' + in step si?e of . it shows current value of/$T. @ecrease y 5 ut increase y >. Jhen it reaches ?eroit results in normal @/8 Call.11 R Timeout Counter 0MA;) This parameter denes themaDimum value of the radio lin) counter eDpressed in S%CC7

loc)s. /ange of ' + in step si?e of . it shows current value of/$T" #ormally 5+" >&" >.12 MS Be&aior Modi<ed) This window shows current settingsfor the moile station" for instance whether handover is disaledor multiand reporting enaled.

Serin* = !ei*&+or Parameter%

1Cell !ame) #ame that descries the neighoring cell as per

the cell le.2ARC!) Channel numer moile receives as neighor.3BSIC) 3SIC of the neighoring cell.4R-e) /eceiving $evel in d3m of neighoring cell.



5C1 > C2) These are the cell path loss criterion and cell

reselection criteria. 0alid during idle mode of moile station. 6C31 > C32) G/S signal strength threshold criterion C-5

and G/S cell ran)ing criterion C->. 0alid oth in pac)et idle

and pac)et dedicated mode.

Step% ?or :T@1

P&'%i(al eri<(ationhysical 0erication is carried out y verifying physical parameterof the #ew Site with the TSS/ Technical Site Survey /eport; suchas %ddress" $at" $ong" 3uilding 7eight" %ntenna 7eight" %ntenna

Type" 8rientation" Tilt.Alarm eri<(ation%larms are generated mainly due to numer of reasons" and

these needs to chec) efore @rive is eing carried out for the Site.%larms are chec)ed from the #8C #etwor) 8perating Centre;and if found needs to e veried efore drive eing carried out.re,uen(' Plan eri<(ation2re!uency lan can e veried from the #8C #etwor) 8peratingCentre; for 3CC7 and TC7 fre!uencies eing implemented as perthe Site Integration Sheet sent to #8C #etwor) 8peratingCentre;.7ardware Conguration 0erication

7ardware verication is performed to )now the Site type" 3TS Type" T/A Conguration" 0SJ/ chec)ing" ower measurement foreach T/A.

Step% ?or :T@2ollo9in* i% t&e pro(edure and parameter% t&at need to(&e(ed 9&ile per?ormin* :rie Te%t ?or a !e9 Site.

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KCC Cell arameter Chec);KM8C Moile 8riginated Calls;KMTC Moile Terminated Calls ' repaid to ostpaid;KSMS Short Messaging Service;

KG/SKIntra Site 7andoverKInter Site 7andoverKT/A TestKIdle @rive #ormal @rive = 2re!uency $oc) @rive;K@edicated @rive

Step% ?or :T@3CPC 0Cell Parameter C&e(Given are the parameters that need to e chec)ed whileperforming CC.CGI Cell Gloal Identity; consists if MCCB#CCB$%CBCI3CC7 2re!uency3SICGSM 3and

Step% ?or :T@4MC and MTCGiven are parameter need to e chec)ed while performing M8Cand MTC/A $evel *< d3m to *55& d3m;/A uality & to <;SI >& to -&;@TA7S# 7opping Se!uence #umer; & to +-;

M%I87opping 2re!uencyC4 I /atio 5, d3m;C4 % /atio 5> d3m;

Step% ?or :T@5GPRS 0General Pa(et Radio S'%tem









This is performed to chec) whether G/S is wor)ing on the Site. This is done y rowsing a we page in rowser of the phone.2or G/S to e chec)ed it is necessary to see that the handset is

J%" G/S enaled.

Step% ?or :T@6TR; Te%t

T/A Test is done to chec) whether calls originated are einghandled y all the T/ALs. Call made during the process is trac)edy the M%I8 numer displayed on the screen for all the T/ALs.E.g. for Site of conguration + T/A per sector the M%I8 values for

T/A test shall e &" 5" >" -" . Call can e originated on the 3CC7or the TC7 fre!uencies. 7ence M%I8 values will e reFected onlyfor calls on TC7 fre!uency and not on 3CC7 fre!uency.

Step% ?or :T@6

Intra Site HandoerIntra 7andover is performed to chec) whether handover is ta)ingplace oth wayson the Site.7andover is performed among all the Sectors of the Site.

Inter Site HandoerInter 7andover is performed to chec) whether handover is ta)ingplace oth wayson the Site with its adacent neighor. 7andover needs to chec)edmandatorilyfor primary neighor.


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http://www.cellular-planningoptimization.com/2010/02/steps-for-dt-6_22.html




7andover is performed with the entire dened neighorNs in theintegration sheet.

Step% ?or :T@"Idle :rie i% per?ormed in t9o ?a%&ion%)@

!ormal :riere,uen(' o( :rie

!ormal :rie This is done to frame the potential area of the new site planned. Italso helps us to get to )now the important neighoring sites forwhich the handover has to ta)e place.

re,uen(' o( :rie This is done y loc)ing the 3CC7 fre!uency of the serving cell andperforming the drive for the same cell unless the moile entersinto #o Service Mode. This is useful for ma)ing decision relatedto GSM antenna height" tilt" and orientation.

:edi(ated :rie@edicated drive is an important part of @rive Test. 7ere call is

made to a test numer and drive is done for the potential areas of the Site. @uring drive eing carried out one has constantlymonitor parameters such as /A $evel" /A uality" SI" @TA" C4I/atio" 7opping Channel" #eighor list" T% Timing %dvance;.Constant changes in this parameter are helpful for post 8ptimi?ation of the site.



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Drive Test Learning:

1) What is the motivation behind GSM Air Interface drive testing?

Ans) GSM Drive testing is traditional and best way to verify networ !erformance for "ew Sites or

#$isting sites.

Drive testing can be ased for vario%s ob&ectives lie'

(overage verification

"ew site erformance *erification and +ield o!timi,ation

"etwor roblem tro%ble shooting lie Dro! calls- andover fail%re- oor (overage !atches- oor

/0 %ality !atches- etc 2enchmaring Drive test to find o%t (overage and %ality com!arison against com!etitors

networs.

3) 4y!es of Drive 4ests?

Ans)

"ew Site Drive 4est 5(overage Drive)

2ench6maring Drive 4est 5(om!arative Drive)

Migration Drive 4est 5"ight activity and Software 7!6gradation)

/o%te Drive 4est.

3) ow to do (overage verification Drive test?

Ans) 2est way to do it by !%tting 4#MS hone in Idle mode and drive across targeted ro%tes .

In Idle mode- MS will meas%re 2(( 4/08s 4ime slot 9 and 4S 9 transmit always f%ll !ower

which is consider as real foot !rint of 2(( 5 which is call as (ell foot !rint ) and s%ch /0

:#*#: is /0 :#*#: +%ll beca%se 4IM#S4;: 9 doesn8t have D40 and ;W#/ (;"4/;: 2%t when yo% do Dedicate mode Drive testing then 4( 4/0 has most of the time D40 ;"

and ;W#/ (ontrol too so that /0 :#*#: Meas%rement is /0 :#*#: S72 which is not

gen%ine (ell foot !rint.<) What is the information need to be collected and carry before to start any Drive testing wor?

Ans) we go for Drive test- we need to collect all re=%ire information for site or gro%! of sites 5cl%ster)

lie'

Site Master Database- which has Antenna !arameters lie A,im%th- antenna tilts- Antenna 4y!e-

eight- 4ilt- A,im%th5 hysical *erification and ;!timi,ation)

Digital Ma!s for D4 +re=%ency lan for Sites incl%ding 2(( and o!!ing 5 +re=%ency ;!timi,ation and

Interference detection) "eighbor :ist so we can com!are who is missing for addition or %nnecessary defined for removal

5 "eighbor ;!timi,ation) (om!lete tools lie D4 >its- (amera- (am!ass- etc

/igger with re=%ire tool for hysical o!timi,ation changes

Drive test desired ro%te if any s!ecific

) What need to be chec when yo% reach to any new sites for Drive test?



Ans) when we reach to site- 1st thing need to be done is Sites Antenna !hysical !arameter

verification

If any antenna !arameter is wrongly im!lemented lie A,im%th or 4ilt then there is no

%se of doing drive test ;nce Antenna !arameter chec and all are as !er re=%ire or !laned- then we can start

call testing - handover testing and area coverage verification Drive testing can be done with vario%s testing scenario b%t widely done as !er below '

(all testing cell wise to %nderstand !erformance of cell and each 4/0Inter cell between same site handover testingInter cell between different sites for handover testing(overage verification drive till yo% get 6@ d2m /0 :evel +%ll in idle mode+re=%ency lan chec 2(( and o!!ing (BI *erification/0 %ality S%b in Dedicated mode

D%ring Drive test some time yo% might face- (all dro! - andover fail- 2loc call- Cetc and in

that8s case we need to do some analysis and yo% have find o%t who is service cell when we had

s%ch !roblem

) What are the ma&or ca%ses behind bad =%ality d%ring the call?

Ans) Ma&or ca%se behind oor /0 %ality is Interference and call can s%ffer interference d%e to

vario%s reasons lie'

(%rrent serving cell /0 :evel5 ( )is !oor so ( is very close to Interference 5 I )

D%e to Missing neighbor- (all is dragging on c%rrent !oor servicing cell and after

sometime it will s%ffer Interference D%e to closely re%se of (o(h- even Mobile is closer to (ell sites b%t interference 5 I ) is

very strong which might red%ce (BI margin

ardware iss%es- and d%e that /eceiver can loose sensitivity so it8s become moresensitive to Interference

Sometime 4arget cell is strong b%t doesn8t have free ca!acity to tae handover so call will

drag in serving cell and it will s%ffer interference

4here might be more reason behind bad =%ality C.

E) What is 2(( oll%tion? ow to overcome from s%ch !roblem?

Ans) 2(( oll%tion mean- more than at any location if MS is getting more than < GSM (ells

and none of them are dominating and most of their /0 :#*#: difference is less than < d2-

means Mobile is %nnecessary will be in F(ell reselection in idle more or Fing ong handover

in Dedicated mode 2est way to overcome from s%ch !roblem to ;!timi,e Antenna !arameter

and remote s%ch heavy overla!!ing.

H) What is cell overshooting?

Ans) D%ring GSM (ell !lanning- /+ lanner has design each cells s%ch way to serve s!ecific

area of target -2ase on (ell !lanning +re=%ency and "eighbor also !lanned- 2%t sometime d%e



to !ro!agation friendly cl%tter or wrong Antenna !arameter !lanning (ell coverage goes beyond

desired area and create interference .

S%ch cell doesn8t add any val%e in networ !erformance b%t they create more

interference to other cell and res%lting in high dro! call. 7sing Drive test yo% can find o%t s%ch overshoot (ell and fine t%ne Antenna !arameters

lie eight or 4ilt or C and restrict their !ro!agation to s!ecific area.

) What are the !rominent res%lts behind (A:: D/;?

Ans)

:ow Signal Strength 52ad /$ :evel)

Missing "eighbor 5andover not define)

2ad /0 %ality

Delayed andover d%e to lac of ca!acity in target cell

Interference

24S related hardware

4( Activation +ail%res D%ring (all

ardware roblem

/adio :in 4imer o%t 5when becomes ,ero).

What to do when (A:: Dro! ha!!en?

We need to %nderstand who is serving cell

(all was in 2(( or 4(Bo!!ing 4/0

We need to %nderstand who is serving cell after call dro!

If serving cell change after dro! call then need to find o%t that and 2SI( was there in

neighbor list- if not means this is missing neighbor

What was the (BI? is it better than @ d2 or bad- If it8s bad means there is (o(hinterference in D:

@) and over +ail%re reasons?

Ans)

:ow signal strength or bad =%ality on target cell.

ardware !roblems in target cell

Interference in target cell

What to do when handover fail%re ha!!en?

+ind o%t who was serving cell+ind o%t who was target cell from layer < message 5 ; (ommand )

19) What is difference between #lectrical tilt and Mechanical tilt?

Ans)



In %rban area mostly now a day8s #lectrical tilt %sed- and reason is when yo% give tilt

%sing # tilt - font and bac lobe both get tilted which red%ce interference in networ- and

also sha!e of Main lobe doesn8t get change only si,e become small In case of Mechanical tilt- if yo% give tilt then font lobe will get tilted and bac lobe will

%! tilted which might create interference to other cells- and also sha!e of main lobe will

get wide which again create interference in networ so that8s why s%ch antenna can be%se in r%lar or highway ind o sites where intra site distance is high and those ind of

area are not m%ch sensitive to interference.19) What is /adio :in 4imeo%t 5 /:4 )?

Ans) /adio lin time o%t is bi6directional co%nter- it will set as !er !arameter when call started

in Downlin in Mobile and %!lin at 4/0 in that !artic%lar timeslot

/:4 is a!!lied only when call is on 4( D%ring call in 4(- in Downlin "etwor send

System info and E which is carrying very im!ortant information abo%t neighbor - cell

and !ower control related in every 9 ms 5 1 com!lete SA(( /adio bloc)- if Mobile

cannot able to decode 1 SA(( bloc then /:4 will red%ce by 1 and if it decode SA((

2loc then it will increase by 3 and if it8s become 9 means call is dro! d%e to some

downlin !roblem and D4 #ngineer has to find o%t and co6related c%rrent /+

Meas%rement and !arameter with (all dro! .

11) DA4A :I"> +AI:7/#?

Ans) If yo% come across any data lin fail%re in sites it means that !acets are not sent

!ro!erly. So from /+ side we have to chec whether any interference is there or not.

13) Why /$ :evel is in negative? What is its %nit?

Ans) we now that'

ower 5in Watt) J 19 log19 5).

Since available !ower is in mill watts so

19 log19 5B19K<)

J 19 log19 5L19K6<)

J 6<L19 log19 5)

J /$ :evel in negative.

1<) how can we red%ce (o6channel interference?

Ans)



1) +re=%ency o!!ing3) D40 mode o!eration

1) what are the !arameters !resent in (%rrent (hannel Window?

Ans)

1) (ell "ame3) (GI 5 M((- M"(- :A(- (I)<) (ell G/S S%!!ort) 2(( A/+(") 4( A/+("E) 2SI(H) 4ime Slot) 2and@) (hannel 4y!e19) (hannel Mode11) S!eech (odec13) (i!hering Algorithm

1<) o!!ing (hannel1) o!!ing +re=%ency 1) MAI;1E) S"

1) what are the !arameters !resent in /adio arameter window?

Ans)

1) /$ :evel3) /$ %ality <) +#/ 5+rame #raser /ate)) 2#/ Act%al 52it #raser /ate)) SI 5S!eech %ality Inde$)E) (B I WorstH) MS ower (ontrol :evel) /: 4imeo%t (o%nter@) MS 2ehavior Modified19) D406 Discontin%o%s 4ransmission.11) 4A 4iming Advance

1E) what is cBI?

Ans) Its (arrier to interference ratio. It is the ratio of !ower of carrier to the !ower of all the

so%rces !rod%cing interference.

/anges'

13 to <3 #$cellent. to @ oor.

@ to 13 Average. to Worst.

1H) What is /$6:evel?



Ans) it will be the /eceived Signal Strenth.Meas%red in Mili Desible and it will be always in

negative.

/anges'

6E9 to o #$cellent. @9 to 9 oor.

6H9 to 6E9 Good. 119 to @9 Worst.

9 o H9 Average.

1) What is /$6%ality?

Ans) It is the =%ality of signal means =%ality of voice we can say.

/anges'

9 to < #$cellent.

< to Average.

to H Worst.

1@) What is SI?

Ans) It is the S!eech %ality Inde$ Which is based on "o of frames #rased and "o of 2its

#rased.

/anges'

3 to <1 #$cellent. to 1 Average.

1 to 3 Good. to Worst

39)ow m%ch is (BI if +re=%ency ho!!ing is !resent or absent?

Ans) In case of Absence of +re=%ency o!!ing (BI will be Greater than 13db.In case of

+re=%ency o!!ing (BI will be Greater than @db.

31) What is M (om? +or what !%r!ose it is %sed?

Ans) it8s a !lanning and !ost !rocessing tool.

a) 4o chec interference

b) 4o now abo%t handover relation definition.

c) 4o find any site in ma!.

d) 4o mae !t of /$ :evel- /$ %ality- (BI worst- SI- etc.

33) What is swa!?



Ans) Sometimes- 40B /$ coming from GSM Antenna gets mismatched while getting

connected with 4/7 cards. So- SWA get occ%rs. It8s of two ty!es- artial N Sectoral.

If com!letely 40B /$ of one sector gets connected to 4/7 (ard- sectoral swa! is there.

If one of the 40 or /$ gets mismatched with 4/7- !artial SWA is there.

3<) What is Dongle?

Ans) It is the license ey for the networ radio !arameters. It is %sed with 4#MS - /;2#

and "#M;.

3) What are MAI; and S"?

Ans) MAI; is Mobile Allocation Inde$ ;ffset which shows from where the o!!ing will

starts.

S" it is o!!ing Se=%ence "%mber will shows the different algorithms %sed in +re=%ency

o!!ing.

When an ongoing call the o!!ing will be 31H times in 1 sec.

3)What is 4A?

Ans) it is 4iming Advance Which Shows ow m%ch meters we r away from 24S. If 4aJ9

means we r 99m away from 24S.

Jhat is the relation lin) etween /AO%$= 2E/P: Jhat is the relation lin) etween /AO%$= 2E/P

%ns: T&e relation o? do9nlin 7R and R;DA wasmeasured during a 27 trial. The relation is clearly diHerent in thehopping case compared to the non*hopping case. Thedistriutions of 2E/ in each /AO%$ class are presentedin 2igure <*5 and 2igure <*>. 8ne clear oservation can e madeQin the non*hopping case there are signicant amount of samplesindicating deteriorated !uality 2E/5&; in /AO%$ class ,while in the hopping case the signicant !uality deterioration

2E/5&; happens in /AO%$ class +. Thus" it may econcluded that in the fre!uency hopping networ)s signicant!uality deterioration starts at /AO%$ class + while in non*hopping networ) this happens at /AO%$ class ,.

This improvement of 2E/ means that the higher /AO%$ valuesmay e allowed in a fre!uency hopping networ). /AO%$thresholds are used in the handover and power control decisions.

http://letstalkaboutcellular.blogspot.com/2010/06/what-is-relation-link-between-rxqual.html

http://letstalkaboutcellular.blogspot.com/2010/06/what-is-relation-link-between-rxqual.html



3ecause of the improvement in the relative receptionperformance on the /AO%$ classes *+" the /AO%$ thresholdsaHecting handover and power control decisions should e sethigher in a networ) using fre!uency hopping networ). In a

?re,uen(' &oppin* net9or R;DA (la%%e% $@5 areindi(atin* *ood ,ualit'.

Typically" the share of the R;DA (la%%e% 6 and " ma'in(rea%e a?ter H i% %9it(&ed on" even if noother changes have een made. This may seem to e surprisingsince it is eDpected that fre!uency hopping improves the networ)!uality. 7owever" in most cases the !uality is actually improved"ut the improvement is more visile in the call success ratio. The

improved tolerance against interference and low eld strength in27 networ) means that it is less li)ely that the decoding of S%CC7frames fails causing increment in the radio lin) timeout counter.

Thus" it i% le%% liel' t&at a (all i% dropped +e(au%e o? t&eradio lin timeout. Instead" the calls generating high /AO%$samples tend to stay on. This may lead to increase in the shareof/AO%$ +*<. 7owever" at the same time the call success rate issignicantly improved.

In the 2igure <*-" there are presented some trial results of a @$/AO%$ distriution with diHerent fre!uency allocation reusepatterns. %s can e seen from the gures" the tighter the reuseecomes" the less samples fall in !uality class & and moresamples fall in !uality classes 5*+. ThereLs igger diHerence indownlin) than in uplin) direction.

This diHerence is a conse!uence of interference and fre!uencydiversities that aHect the fre!uency hopping networ). 3ecause ofthese eHects" the interference or low signal strength tend to occurrandomly" while in a non*hopping networ) it is proale thatinterference or low eld strength will aHect several consecutiveursts ma)ing it harder for the error correction to actually correcterrors. The successful error correction leads to less erased framesand thus improves the 2E/.



: 7-plain in +rie? 9&at i% 7R.

An%)• 2E/R #umer of erased loc)s total no of loc)s 5&&

• It is the right measure of voice !uality.

• 2E/ is performed on speech= signaling frames

• 2E/******* & to " G88@.

> to 5, " slightly degradedGreater than 5," useless

GSM !7TERFPTIMIATI!

ues; what is @ropped CallP

%ns; %ll cell resources are availale ut calls are failing" then we

have a call drop scenario. This could e caused y software

errors" congestion" C< lin) failures" 7J prolems or many other

reasons.

ues; S@ 3loc)ingP

%ns; S@ loc)ing means that you are not getting S@ resource for

the call origination. Jhen MS connects with #J then /%C7 and



%GC7 are provided. %fter %GC7" S@CC7 is provided ut if S@CC7

is not provided at this time due some prolems or due to

unavailale of S@ y 3SC "itLs called as S@ 3loc)ing.

/easons for S@ 3loc)ing: $%C oundary" 7J ro.

Solutions for removal of S@ 3loc)ing: Chec) the #o. of S@CC7channel %vailale" if less then increase S@ channel ta)ing care

that there is no TC7 3loc)ing" 7ardware chec) 4 shift S@ to new

time slot"Ose of @ynamic S@CC7 It is a 3SC parameter and will

e applied on whole 3TS;

ues;

S@ @ropP

%ns; when we assigned S@ for call

origination and at that time due to some prolem or any

mismatch comes y which S@ loss occurs" it is called as S@ @rop.

It occurs etween allocation of S@ and efore TC7 allocation.

If S@ drop is high pl? loo) on parameters li)e* overshooting "

shift the S@ time slot " may e hardware issue" interference"

@$ provide tilt "re orient that antenna.

/easons of S@ @rop: 7ardware 2ault" Interference" 8vershooting"

%is @rop" 7igh ath $oss.Solutions for removal of S@ @rop:

Interference: Chec) the 3CC7 lan C4I or C4%;" Co*3SIC = Co

3CC7. The est way to nd the real issues for Interference ma)es

@T" Chec) interference y Interference scanning" Chec) clean

3CC7 y fre!uency scanning. 8vershooting: Cell orientation need

to e dened according to clutter" EHective Tilt. 3ad Coverage: If

the drop call is due to low signal strength uplin)" chec) the

receive path of this particular T/A. Chec) receiver sensitivity"

0SJ/" feeder connection and etc. @rops due to $ow Signal

Strength.

ues; TC7 3loc)ingP

%ns; Jhen TC7 is not allocated to the

user after S@ allocation" it is TC7 3loc)ing. It is the failed call

attempts which the MS user can notice. It ta)es place due to lac)

of TC7 /esource. /easons for TC7 3loc)ing:



7igh Otili?ation of TC7" Time slot faulty" $oc) T/As" 7Jrolem.

Solutions for removal of TC7 3loc)ing: Implement half rate or @ual

rate" %dd another T/A" If T/A addition not possile" try to share

the tra9c of that cell with the neighoring cell y changing tilt or

orientation.

ues; TC7 @ropP

%ns; @rop during conversation is )nown as TC7 drop. It

ta)es place after connect %CU msg on TC7. /easons for TC7

@rop: Jrong arameter lanning 8vershoot" 7ardware 2ault" @ue

to $ow Coverage" 3%@ 78S/.

Solutions for removal of TC7 @rop: Chec) arameter: Chec) the

3CC7 lan C4I or C4%;"Co*3SIC = Co 3CC7. Chec) 8vershooting: If

a cell is pic)ing call from long distance" Chec) the sample log

according to T%" Site 8rientation" and EHective tilt should e

chec). 3ad Coverage: If the drop call is due to low signal

strength uplin)" chec) the receive path of this particular T/A.

Chec) receiver sensitivity" 0SJ/" feeder connection and etc. If

the drop call reason is due to low signal strength downlin)" then"

chec) the transmit path. Chec) cards" feeder and etc.

ues; 78S/P %ns; if 78S/ will e good TC7 drop will also e good. If

7andover success rate degrades call drop rate will ta)e place.

/easons for oor 78S/: Improper #eighor planning" C8*3CC7*

3SIC issues in #eigh" $%C oundary 8vershoot" 7J Issues %nd

$ow Coverage.

Solutions for removal of 78S/: 5. The est way to nd the real

issues for 78 fail ma)e @T and chec) layer - msg for 78 fail. 3y

@T it is very easy to nd the fail etween cells.>.

%void C8*3CC7*

3SIC neighors" %void eDtra neighs" @elete long distance neighs"

Chec) neighs are dened form oth ends.

8vershoot: Jhen neighs are far away then chances of 78 fail

increases. In this case ping*pong 78 ta)es place y which fail



ta)es place. So if the inter distance is high itLs etter to delete

that )ind of neighor.

ues; TC7 %ssignmentP

%ns; itLs a process of y which TC7 is assigned to the MS. %fterthe S@ re!uest MS gets TC7 successfully and the call transfers to

TC7 it means TC7 assignment is successful.

Solutions for removal of TC7 %ssignment: I2 T/As are faulty loc)

them and try to replace them soon to avoid loc)ing" Connection

from 3TS to %ntenna" Connector connection" Clear 0SJ/

FPI A!ASIS 8P7RRMA!C7

A!ASIS07RICSS!

o9 Si*nal Stren*t& Anal'%i%

$etLs starts todayLs topic that is $ow signal strength analysis.

Jhat could e the proale cause of low signal while

you drive or optimi?e. 2irst see the following Fow chat and try to

understand the things

/ememer that

!T7) @ $ow Signal strength is one of the reasons of drop call. It

can e indicated y many calls disconnected at low signal

strength y suscrier" drop calls due to eDcessive T%" poor

handover performance and poor call setup performance.

E&at (ould +e t&e pro+a+le rea%on%

roale /eason

#o dominant

cell

Cell might e isolated or standalone.

%ntenna tilt

=

Too much down tilt sometimes might not cover a

http://www.cellular-planningoptimization.com/2010/02/low-signal-strength-analysis.html









orientation larger area and the suscrier might lose the SS.

8utput

ower

$ow output power might cause smaller order cell.

Ju%t tr' to o+%ere 9&at (ould +e t&e ri*&t (au%e)@

T&e ?ollo9in* pro(edure %&ould +e per?ormed ?or lo9

%i*nal %tren*t& anal'%i%)

5: Identify the aseline re!uirement of design and 3SC eDchange

property setting for $8JSSO$4$8JSS@$;.

>: Chec) the value for $8JSS@$ = $8JSSO$. If it is higher than

%CCMI#" change the parameter to a reasonale value since thedrop reason will e more priority to SS compared to uality.

-: Chec) the site position" antenna direction" position etc. This is

to ensure the possile location is open to interference open

water environment; or isolated. Good map is needed for this.

: Chec) if the site is sectori?ed or 8mni. If it is 8mni" set the cell

into sectori?ed cell.

,: Chec) if the signal strength is uplin) or downlin) limited.

Mostly" It is designed to e downlin) limited.

+: Chec) the coverage cover eDpected area from the planet. If it is

not" chec) the antenna tilt and orientation. Change the direction

or tilt if it is too much down tilt or pointing to a wrong direction.

<: Sometime" low output power might cause low SS. Chec) output

power and if it is low" increase the output power.

6: Chec) cell whether it has hotspots from drive tests. If found "

adding new site is recommend.

(: In order to chec) power distriution" run Cell Tra9c /ecording

CT/; to that particular cell.





5&: Chec) if the cell has indoor coverage prolem. If yes" add

micro site instead.

TCH A%%i*nment Anal'%i%)@

Successful assignments show the numer of successful TC7 allocations at call setup.%t unsuccessful assignment" the %ssignment Complete message"sent y the MS" was never received y the 3TS.

The formula is dened as:

TC7%SSIG#ME#TSOCCESS /%TE

RT2C%SS%$$ A 5&&

T%SS%TT

roale /eason

#o dominantserving cell

The serving cell cannotcope with the TC7 tra9c.

Severe congestionon TC7

2ailing TC7 allocation forassignment or handover

due to congestion$ow signal strength for call access

The signal strength mighte higher on the 3CC7than on the TC7.

Interference @isturance on S@CC7 ortarget TC7

2aulty transceiver 2aulty e!uipment

T&e ?ollo9in* pro(edure %&ould +e per?ormed ?or TCH

A%%i*nment anal'%i%)5: 2or TC7 assignment success rate" the rst thing" chec) the TC7

Time Congestion.>: If there is congestion on TC7" it is recommend doing thedimensioning and adding T/O ased on carried TC7 tra9cdemand.

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-: If there is no congestion on TC7" chec) the output power of the3TS. If the output power is low" increase the output power.: If the output power is o)" chec) the faulty 3TS y eDtracting3TS error log.

,: If hardware fault found" swap or repair 7J.Per?orm drie te%t% to (&e( t&e (oera*e and re(eiedR-e.+: If no dominant cell or similar signal strengths of a few cellsfound during drive tests" it is recommended to add 3TS.<: If there is no prolem on the dominant cell" chec) theinterference whether co*channel or adacent channel.6: Chec) the disturance whether it is on S@CC7 or target TC7. Ifdisturance found" improve the fre!uency plan.Mo%tl'K t&e pro+lem% o? lo9 TCH a%%i*nment are

TCH aaila+ilit' and inter?eren(e.

Inter?eren(e Anal'%i%

T&e ?ollo9in* pro(edure %&ould +e per?ormed ?orinter?eren(e anal'%i%) 5.; Chec) the drop callperformance for that particular cell. Jhen the interferenceprolem occurs in the cell" the drop call will e higher than usual.

This might depends on the severity of the interference whether it

is co*channel or adacent channel.>.; Chec) the handover performance of the cell. The 78performance will also loo) ad especially when you loo) into theneighor relation that has interference. 2or e.g. adacent channel.-; Chec) the antenna direction" position etc. This is to seewhether the direction covers the right area" open space area thiscan e seen y having good and updated map;

; Chec) if the site is a dragon site. If the site is a dragon site" it

might e possile to get interfered y co*channel from far away.Chec) the co*channel sites" if found" change fre!uency and seethe result. Mostly" changing the fre!uency will solve theinterference prolem.

,; Chec) the Intracell handover normally for Intracell handover>, Oplin) and <, @ownlin); and if the variation is diHerent

http://www.cellular-planningoptimization.com/2010/02/interference-analysis.html




from this. Intracell handover usually indicates ad !uality andhigh signal strength. Too high numer of Intracell handover showa ad !uality cell and if possile" you can reduce the numer ofIntracell handover of M%AI78 to a smaller value ased on the

channel group.$ocate the interference from statistics ased on MS reversion toold channel of total attempt. 7igh numer of reversion will showthat the target fre!uency might e interfered.+; Chec) the statistics from 8utgoing 7andover decision due toad !uality Oplin) or @ownlin) from handover decision. 7ighdecision of handover due to !uality will show the direction ofinterference.

Chec) if the interference is uplin) interference this might e an

interference from other MSs; y analy?e the ICM and for otherand not include and 5;. If found on ICM -" change fre!uency.

<; Chec) the MS power regulation setting. If any poor settingfound" correct the parameter. Improper setting of MS powerregulation might cause interference. The feature used to reducethe MS power when the MS is near to the 3TS and hoping that itmight not interfere the uplin).

6; Chec) if the fre!uency hopping on or oH. If more than 5 T/O"turn on the fre!uency hopping. Turning on the fre!uency will helpto reduce interference y interference averaging.

(; Chec) if @TAO feature is on or oH. If oH " turn the @TA featureon. This will save the attery in the MS and reduce theinterference.If the interference is downlin) causing y other 3TS interference;"Chec) 3TS power regulation. If any poor setting found" correctparameter setting.

5&; Chec) if @TA@ feature is on or oH. If oH" t urn the @TA featureon. This is used to reduce interference and decrease 3TS powerconsumptionIf changing fre!uency or parameter cannot solve the interferencefor oth uplin) = downlin)" it might e eDternal interference.






55; Chec) antenna installationQ ensure that the antenna iscorrectly installed

5>; Chec) if another moile networ) li)e %MS is near tothe location.5-; Chec) from the statistics if there is any pattern of ad !ualityreason. 2or eDample" for surveillance purpose" the CCT0 orwireless alarm system might e turn on during nighttime only.If eDternal interference prolem occurs" do drive test and reportthe usage of the fre!uency to authorities.

Con*e%tion Anal'%i% Tra9c congestion is one of the maor networ) prolems ina moile system. % high congestion deteriorates the overallperformance of the networ) and should e minimi?ed.

1) S&ort term *ro9t&

If the high tra9c related to an occasional event" li)e sports event"fairs" conference" a temporary solution might e considered.

2) on* term *ro9t&If there is a long*term growth the networ) capacity has to growaccording to the demand.

Type of Congestion

The congestion analysis egins y identifying if there is onlyS@CC7 or TC7 congestion or oth. Congestion on oth S@CC7and TC7 may mean that the only way to get rid of the congestionis to add more physical capacity in terms of transceivers or sites.

HSR Anal'%i%Pro+a+le Rea%on% o? Bad Handoer Per?orman(e)@1 !ei*&+orin* Cell RelationA(tion) %dd neighor cell relation.



http://www.cellular-planningoptimization.com/2010/02/congestion-analysis.html


http://www.cellular-planningoptimization.com/2010/02/hosr-analysis.html








2 Mi%%ed mea%urement ?re,uen(ie% in BA@li%tA(tion) Chec) measurement fre!uencies list.

3 Permitted !et9or Color Code pro+lem

A(tion) Chec) #CC ermitted4 HE ?ault%.A(tion: Chec) 3TS error log.

5 Blo(in* on Tar*et CellA(tion) /emove 3loc)ing on Taget Cell

6 Con*e%tion% high congestion might lead to dragged calls handover

performed at a not intended location; and a lot of unsuccessfulhandovers.A(tion: Chec) TC7 congestion.

" Timer 7-pire A?ter MS i% lo%t The MS never answers the ase station.A(tion: Chec) coverage. Chec) interference.

# in Conne(tion or HE ailureA(tion: Chec) 3TS error log. erform site visit. erform lin)performance measurements.

Bad Antenna In%tallationA(tion: erform site survey and chec) antenna installation. Chec)antenna caling.

1$ Man' !ei*&+or% :e<nedMany dened measurement fre!uencies dened 5+; willdecrease the accuracy of the moile measurements to locate the

est siD servers. Many measurement fre!uencies mean fewsamples per fre!uency and prolem for moiles to decode the3SIC.A(tion: Chec) numer of denitions.

11 :ela'ed Handoer :e(i%ion



% delayed handover decision can e due to congestion in thetarget cell.A(tion: Chec) handover parameters.

12 Eron* o(atin* Parameter Settin*A(tion: Chec) locating parameters.

13 Bad Radio Coera*eA(tion: Chec) coverage plots.

14 Hi*& Inter?eren(eK Co@C&annel or AdLa(ent The potential handover candidate is distured y interference.8utgoing handover due to ad uplin) !uality may indicateinterference from co*channel another MS. 8n the order" the

!uality may e rather ad and the signal strength low. 3addownlin) !uality may indicate interference from another co*channel ase station.A(tion: Chec) interference. Chec) if many handovers areperformed due to downlin) or uplin) ad !uality.

15; Re(eier Antenna Pro+lem or RBS HE pro+lem% 0in(andidate (ellA(tion: Chec) antenna installation. Chec) /3S 7J and Error log

of the target cell

16 Poor Inter@MSC8BSC Handoer Per?orman(e2or outer or eDternal cell" wrong denitions in either MSC or 3SCmay e reason for the prolem.A(tion: Chec) inter*MSC43SC handover performance.

1" In(orre(t do9n TiltA(tion: erform site survey and chec) antenna installation.Solution: Correct antenna tilting.

7-(e%%ie Timin* Adan(e 0TA





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http://rfoptimisation.blogspot.com/2009/12/excessive-timing-advance-ta.html



@rop call due to eDcessive T% happens when the T% value at drop

call connection is higher than the cell parameter T%$IM T%@/8

T%$IM; and from this counter T2@IST% is incremented.

roale /eason

$ocation 7igh sites or sites neDt to water pic) up tra9c

from far away

arameter

setting

0ery low T%$IM setting" which would indicate

a VfalseL eDcessive timing advance

7ow to analy?e:

W Chec) cell parameter M%AT% and T%$IM. If it covers far coverage"

it is possile to setting of the cell parameters M%AT% and T%$IM to

a higher value for e.g. M%AT%R+-" T%$IMR+>;

W If the cell is really covering far away from the site" other options

are reducing the coverage y down tilting the antennas" reducing

antenna height" changing antenna or reducing output power

W If it is a rural area and need to cover a larger

area" EDtended /ange feature might e useful to e considered.

t&er Rea%on

@rop due other reason e!ual to total numer of drops sutracts all

drops with reason. If any of the aove drop reason didnLt meet the

criteria" the reason for drop will e in the V8ther /easonL.

roale /eason

74J fault 7ardware rolem Managed 8ect in 3TS;

@isturance $in)4 Transmission disturance prolem



arameter

Setting

Jrongly dened setting for e.g. $%C

' $ocation %rea Code;

Moile Station MS prolem

Interference Interference prolem Oplin);

7ow to analy?e:

W Chec) the 3TS error log for hardware faults. /un commands:

/AE$ = /AM2 to loo) the hardware faults log;

W Chec) if ICM is indicating uplin) interference in the cell.

W Chec) with 8=M regarding transmission prolems" 7J prolems

and service aHecting maintenance wor) during the time period.

The average cell downtime and TC7 availaility should also e

chec). It might e intermittent lin) connection.

W Chec) oect type M8TS" which is ased on drop on Timeslot

TS; in order to nd faulty devices.

TCH :rop Anal'%i%

1. Radio in Time@ut

Every time a S%CC7 message cannot e decoded the radio lin)

time*out counter is decreased y 5. If the message can e

decoded the counter is incremented y >. 7owever" the value

cannot eDceed the initial value. The initial value is set ythe parameter /$I#UT for radio lin) time*out in the moile station

and y /$I#UO for timeout in the 3SC. If the moile moves out of

coverage and no measurement reports are received in the 3SC"

there will e a radio lin) time*out and the message Channel

/elease cause: anormal release" unspecied; is sent to the

http://www.cellular-planningoptimization.com/2010/02/excessive-timing-advance-ta.html

http://www.cellular-planningoptimization.com/2010/02/tch-drop-analysis.html

http://www.cellular-planningoptimization.com/2010/02/excessive-timing-advance-ta.html




moile station and the S%CC7 is deactivated in the 3TS. % Clear

/e!uest message is sent to the MSC. To e sure that the moile

has stopped transmitting" the 3SC now waits /$I#UT S%CC7

periods efore the timeslot is released and a new call can e

estalished on the channel.

2. a'er 2 Time@ut

If the 3TS never get an ac)nowledgement on a $ayer > message

after the time T>&&A#>&&" the 3TS will send Error Indication

cause: T>&& eDpired; to the 3SC" which will send Channel

/elease cause: anormal release" timer eDpired; to the moile

station and a Clear /e!uest to the MSC. The S%CC7 is deactivatedand the 3SC waits /$I#UT S%CC7 periods efore the timeslot is

released and a new call can use the channel. This is only valid if

the call is in steady state" i.e. not during handover or assignment.

3. Relea%e Indi(ation

Jhen the 3TS received a layer > @ISC frame from the moile it

replies with a $ayer > O% frame to the moile station and a

/elease Indication to the 3SC. The system does only react on/elease Indication if it is received during a normal disconnection

situation. If such a message is received uneDpectedly this will

usually cause radio lin) time*out or timer T>&& eDpiration as the

moile station stops the transmitting of measurement reports. It

is also possile that the release will e normal depending on when

the /elease Indication is received.

4. MSC Time@ut

#ormal /elease:

If the MSC never received a response on a message e.g. Identity

/e!uest; and there is no radio lin) time*out or layer > time*out"

the MSC will send a Clear Command to the 3SC. The time*out is

depending on the message. Jhen receiving Clear Command" the



3SC will send a Channel /elease cause: normal release; and then

deactivates the S%CC7.

/eect only S@CC7;:

If the MSC never receives a response on the rst message afterEstalish Indication" the MSC will send a reect message. If the

connection was a $ocation Opdate it will e a $ocation Opdate

/eect cause: networ) failure; and if the connection was a moile

originating call CM Service /e!uest; a CM Service /eect cause:

networ) failure; will e sent. The MSC will then send a Clear

Command to the 3SC and the call is cleared y Channel /elease

cause: normal release;.

5. A%%i*nment to TCH

3efore sending an %ssignment Command from the 3SC at TC7

assignment" the following two criterions have to e fullled:

a. There must e a TC7 channel availale" i.e. no congestion

. The locating algorithm must have received at least one valid

measurement report.

If either of the criterions is not fullled" %ssignment Command willnot e sent and a Channel /elease cause: anormal release"

unspecied; will e sent to the moile station and a Clear /e!uest

to the MSC.

TCH :rop rea%on 01

The classication of TC7 @rop /easons are arranged in the order

of priority:

5.EDcessiveTiming %dvance

>.$ow Signal Strength

-.3ad uality

.Sudden $oss of Connection

,.8ther /easons

7-(e%%ie Timin* Adan(e



The TC7 @rop counters due to EDcessive Timing %dvance will

pegged when the during the time of disconnection" the last

Timing %dvance value recorded was higher than the

T%$IM arameter. This drop reason is commonly apparent to

isolated or island sites with a wide coverage area.

A(tion)

Chec) if the cell parameter T%$IM is X Y+-Y Solution)

Set T%$IM to a value close to +-.

Tilt antenna4reduce antenna height4output power" etc. for co*

channel cells.

TCH :rop Rea%on% 02

o9 Si*nal Stren*t& on :o9n or Dplin or Bot& in%

The drops counters due to $ow Signal Strength will e pegged

when the Signal Strength during the last Measurement /eport

efore the call dropped is elow the $8JSS@$ and4or $8JSSO$

Thresholds. $8JSS@$ and $8JSSO$ are 3SC EDchange roperty

parameter which is used only for statistics purposes and does not

aHect the ehavior of calls. If oth O$ and @$ Signal Strength areelow the thresholds" only @rop due to $ow SS 3$ will pegged.

#ormally a call is dropped at the order of large rural cell with

insu9cient coverage. 3ad tunnel coverage ecause many

dropped calls as well as so called coverage holes. 3ad indoor

coverage will result in dropped calls. 3uilding shadowing could e

another reason.

A(tion)Chec) coverage plots.

Chec) output power.

Chec) power alance and lin) udget.

Chec) if 8mni site.

Chec) antenna conguration = type.








Chec) antenna installation.

erform drive tests = site survey.

Chec) T/A4TS with high C8#E//C#T.

Solution)%dd a repeater to increase coverage in for eDample a tunnel.

Change to a etter antenna with higher gain; for the ase

station.

%dd a new ase station if there are large coverage holes.

3loc)4@eloc) T/A

TCH :rop Rea%on% 03

Poor ualit' on :o9n or Dplin or Bot& in%

The drops counters due to 3ad uality will e pegged when the

Signal Strength during the last Measurement /eport efore the

call dropped is aove the 3%@@$ and4or 3%@O$ Thresholds.

3%@@$ and 3%@O$ eDpressed in @TO; are 3SC EDchange

roperty parameter which is used only for statistics purposes and

does not aHect the ehavior of calls. If oth O$ and @$ uality are

aove the thresholds" only @rop due to 3%@ uality 3$ will

pegged.

rolem on 3ad uality is usually associated with Co*channel

Interference on 3CC7 or TC7. 2aulty M%I8 assignment can cause

fre!uency collisions on co*sited cells especially on 5D5 /euse.

EDternal interference is also one possile cause of prolem on

!uality.

A(tion)Chec) C4I and C4% plots.

Chec) 2re!uency lan Co*3CC7 or Co*3SIC rolem;.

Chec) M%I8" 78" 7S# parameters.

Chec) 278 if correctly congured 33 or S1;.

Chec) for EDternal Interference.





erform drive tests.

Solution)

Change 3CC7 fre!uency.

Change 3SIC.Change M%I8" 78" 7S#.

Change 278.

/ecord /I/ or on*site 2re!uency Scanning to identify source of

interference.

Ose availale radio features.

TCH :rop Rea%on% 04

Sudden o%% o? Conne(tion

@rops due to Sudden $oss are drops that have not een registered

as low signal strength" eDcessive timing advance" ad !uality or

hardware other; reasons" and the locating procedure indicates

missing measurement results from the MS.

There are some common scenarios that could lead to Sudden $oss

of connections such as very sudden and severe drops in signal

strength" such as when suscriers enter into uildings"elevators" par)ing garages" etc." very sudden and severe

occurrence of interference" MS runs out of attery during

conversation" 7andover $ost" 3TS 7J faults" Synchroni?ation or %*

is lin) fault transmission faults;" and

MS 2aults.

A(tion)

Chec) 3TS Error $ogs" %larms and 2ault Codes.Chec) C8#E//C#T per T/A and TS.

Chec) Transmission $in) %*is;.

Chec) for @I Slips.

Chec) $%@ Congestion.

Correlate 7andover $ost to @rops due to Sudden $oss



Solution)

2iD 7ardware 2aults and %larms.

/eset T/A with high C8#E//C#T.

Ensure that Synchroni?ation and %*is $in) are stale.Change /3$T with high @I Slips.

Change C8#2%CT or increase Transmission Capacity

Investigate 78 $ost rolem

TCH :rop Rea%on% 05

TCH :rop% due to t&er Rea%on%

TC7 drops due to 8ther /easons are computed y sutracting the

sum of drops due to EDcessive T%" $ow SS" 3ad uality andSudden $oss from the Total TC7 @rop Counts. @rops due to 8ther

/easons are generally associated with hardware prolems"

transmission lin) prolems on %*is" %ter or %interfaces" and

sometimes 7andover $ost.

A(tion)

Chec) 3TS Error $ogs.

Chec) %larms and 2ault Codes.Chec) C8#E//C#T per T/A and TS.

Chec) Transmission $in) %*is;.

Chec) for @I Slips.

Correlate 7andover $ost to @rops due to 8ther /easons

Solution)

2iD 7ardware 2aults and %larms.

/eset T/A with high C8#E//C#T.Ensure that Synchroni?ation and %*is $in) are stale.

Change /3$T with high @I Slips.

Investigate 78 $ost rolem



Pro+lem rea%on o? drop in S:CCH

o9 Si*nal Stren*t& on :o9n or Dplin

The reason for poor coverage could e too few sites" wrong output

power" shadowing" no indoor coverage or networ) e!uipmentfailure.

A(tion: Chec) coverage plots.Chec) output power. erform drive

tests. Chec) 3TS error log

Solution: %dd new sites. Increase output power. /epair faulty

e!uipment.

Poor ualit' on :o9n or Dplin

A(tion: Chec) C4I and C4% plots. Chec) fre!uency plan. erformdrive tests.

Solution: Change fre!uency. Ose availale radio features.

Too Hi*& Timin* Adan(e

A(tion: Chec) if the cell parameter T%$IM is X styleRYfont*

weight: oldQYSolution: Set T%$IM to a value close to +-. Tilt

antenna4reduce antenna height4output power" etc. for cochannel

cells.

Mo+ile 7rror

Some old moiles may cause dropped calls if certain radio

networ) features are used. %nother reason is that the MS is

damaged and not wor)ing properly.

A(tion: Chec) MS Feet.

Solution: Inform operator.

Su+%(ri+er Be&aior

oorly educated suscriers could use their handsets incorrectly

y not raising antennas" choosing illadvised locations to attempt

calls" etc.

A(tion: Chec) customer complaints and their MS.





Batter' la9

Jhen a suscrier runs out of attery during a conversation" the

call will e registered as dropped call due to low signal strength or

others.A(tion: Chec) if MS power regulation is used. Chec) if @TA uplin)

is used.

Con*e%tion on TCH

the S@CC7 is dropped when congestion on TC7.

A(tion: Chec) TC7 congestion

Solution: Increase capacity on TC7 or using features li)e

%ssignment to another cell" Cell $oad Sharing" 7CS" @ynamic 7alf*/ate %llocation and 2/*7/ Mode %daptation etc

Summar')

1. S: :rop rea%on% and Solution%)@

5.3ad uality @ownlin) Interference i.e. fre!uency heating>.$ow Signal strength Site 8vershoot i.e. %dust Tilt

2. TCH :rop Rea%on% and %olution%)@

5.$ow Signal strength @ownlin) Site 8vershoot i.e. Increase TiltSite is not ServingMaDimum tilt; i.e.release tilt

>.$ow Signal strength Oplin) Tilt One!ualConnector loose3TS Connection $oose

Tilt Con(ept)0aMain always e (&& eDpansion can e (&& and 56&& "0+In terms of coverage 56&&R(&&> i.e. (&& Mech. Tilt is then 56&&

Mech. Tilt will e >" 0( Tilt for @ense areas ***-" Mechanical

0d Tilt for 8pen %reas****(&& has slight diHerence etween (&& = 56&&e.g. (&&Z<"56&&Z+ " (&&Z<"56&&**,-.I2 $ow Ssl O$4@$ Then chec) all the possile solutions

%vailale for $ow Ssl O$ = @$..3ad uality @ownlin) 2re!uency 7eating i.e. propose



fre!uency,.3ad uality Oplin) ropose C@M% lter

7ardware Issue#eighor 2re!uency 7eating

+.EDcessive T% rovide Tilt

<.8ther @rop /easons 7ardware issuea; T/O heat i.e. %C is not

wor)ing; $oose connectionc; %ntenna %lignment

Rea%on% ?or BA: ualit')It can e serving interference or it can e neighor interference due to

which handover is not ta)ing place.

To Proide re,uen(') Conduct @rive in idle mode and chec) out

the fre!uencies in serving B neighor" propose that fre!uency which is

not appearing in the list.!ote) Same MAI %&ould not +e t&ere +et9een t9o nei*&+or%.

Handoer Reer%al) 2re!uency 7eating or 7ardware Issue

Handoer o%t) MaDimum Tilt site not serving; or 7ardware Issue

Route ptimiation) 0a 2re!uency 7eating0+ Site over Shoot and 7ardware Issue



!oia FPI PTIMIATI!

ptimiation Tip% ?or !oia S'%tem

S:CCH Su((e%% Rate Anal'%i%@!oia S'%tem@1Po%%i+le)

Interference on 3CC7 fre!uencyS@CC7 3loc)ing S@ @rop on $ocation Opdate $%@ 2ail

7J faulty EDcessive T%:ata Colle(tion)

#@ /eport <> to chec) 3CC7 clearance%larm $og T% distriution #@ /eport >-> uality and $in) 3alance #@ /eport 5(, and 5(+. Interference O$ and #@ 5(+

S:CCH Su((e%% Rate Anal'%i%@!oia S'%tem@2

Pro+lem Anal'%i%)5. Chec) possiility Co. or %d. Interference and clear the 3CC7fre!uency.>. Chec) S@CC7 utili?ation and add S@CC7 if needed.-. Change T/ or change S@CC7 allocation on T/A with good!uality ased on #@ 5(+.. Chec) T/A alarm mostly <<, together with<<- or <<+;.Chec) T/A conguration.+. Chec) T% distriution" coverage distriution and propose

physical tune.-. 8ptimi?ing parameter C> also if $ocation update is the highestcontriutor of S@ @rop.. 7ighest contriutor: 2ail on /%@I8" %3IS" %[I2" T/ or $%@.,. Chec) T/A alarm mostly <<, alone or together with <<-;

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http://www.cellular-planningoptimization.com/2010/03/sdcch-success-rate-analysis-nokia_17.html


http://www.cellular-planningoptimization.com/2010/03/sdcch-success-rate-analysis-nokia.html





<. Chec) /A $ev %ccess Min and MaD #umer of /etransmission.Chec) /%C7 /eected and S@CC7 re!uest fails or ghost;.

HSR Anal'%i%@Tip% on !oia %'%tem@1Po%%i+ilitie%)

Co or %dacent 3CC77igh TC7 3loc)ing on target cell Jrong TSC setting regarding 3SIC allocation 3ad #eighor /elation 7J faulty or Onalance T/A power among a sector

8thers Inter 3SC*Inter MSC;Preparation :ata)3CC7" 3SIC planning" #@ report &<>Cell Stat or TM of 78 distriution and #@ report 5,-%larm \E87 = \E8$; and site visit

Timing %dvance >->%dacent Consistency Chec) #@&+&" +> or +(#@ /eport <- to chec) Ondened #eighor.

HSR Anal'%i%@Tip% on !oia %'%tem@2 Pro+lem Anal'%i%)5. Chec) possiility Co. or %d. Interference then change 3CC7fre!uency.>. Chec) neighor tra9c = TC7 loc)ing" chec) possiility fortra9c sharing or directed retry.-. TSC value should e same with 3CC" chec) performance 78 outand incoming.. arameter setting %@]E to ma)e delay on worst target cell or

faster 78 on est target" focused on 7igh 78 2ail. /elateparameter 2MT or %OC$.,. Chec) T/A alarm mostly <<, together with <<- or <<+;.Chec) T/A conguration.+. 8ptimi?e coverage from T% distriution or update missing#eighor from #@ <-.

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<. Chec) the highest handover cause: y interference" !uality"level" power udget" G/S" etc. Chec) for the highest 78 failure:y 3loc)ed" Conn. 2ail." /eturn to 8ld" End of 78" etc. The highestvalue is possile as the highest contriution of 78 fail.

FPI Anal'%i% on !oia %'%tem@TCH drop@1 The rst UI is TC7 drop and its analysis.Po%%i+ilitie%)* Interference on 3CC7 T/A* Interference on hopping T/A @$ Interference;* EDternal Interference O$ interference;* 3ad #eighor /elation ad 78;* $ow Coverage* 7J 2aulty or T/A ower Onalance* 8ther: $%@ 2ailSome Important Report% num+er ?or !oia %'%tem toanal'e t&e TCH drop)Preparation :ata)* 3CC7 lanning" #@ report &<> @$ Interference distriution;

* #@ /eport >5+" 5(+ and %larm Interference;* #@ /eport >&" 5,-" 5(, 78 fail and ath 3alance;* #@ /eport >-> Coverage cell;* #@ /eport 5+- or TM drop per causes

!et9or Plannin*)

2or telecom engineers" it is very help full to )now aout M%I8.3asically there is a set of fre!uencies where the channels are hopto avoid interference that set of fre!uencies is called M%*$IST.suppose M%$IST contained fre!uencies ^%"3"C"@"E"2"G"7"I"]"U"$_.

Then M%I8 corresponds to the starting point of hopping se!uence.Suppose there are four T/D in one sector. then M%I8 will e" foreDample" &">".

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for rst T/D for tra9c" the M%I8 is &. means that hoppingse!uence starts from rst fre!uency in the M%$IST" that isfre!uency %. and for M%I8 > it starts from fre!uency C and forM%I8 it starts from fre!uency E.

%lso 7S# hopping se!uence numer;" ranges from & to +- . if weuse 7S# as" for eDample it means that for M%I8 &" the se!uencestarts from fre!uency % and repeats fre!uencies in followingmanner.

2or M%I8 & and 7S# %"2"U"@"I"3"G"$"E"]"C"7"%"2

2or M%I8 > and 7S# C"7"%"2"U"@"I"3"G"$"E"]"C"7

2or M%I8 and 7S# E"]"C"7"%"2"U"@"I"3"G"$"E"]

C:MA :rie Te%t Parameter%)

T;PE7R2R;PE7R

37(8Io

4T;A:J

57R.

1.7(8Io

Ec4Io reFects the handset in the current received pilot signal level. This is an integrated pilot signal. Jhy" ecause moile phones are

a multi*channel soft switching" which translates into moile

phones often lies in more than one pilot overlapping coverage

area" the level of the phone" Ec4Io reFects the phone at this point

that a multi*channel pilot signal level of the overall coverage. Je



)now that the Ec is a moile phone availale pilot signal strength"

and Io is the moile phone receives all the strength of the signal.

Therefore" Ec4Io reFects the availale signal strength in occupies

all signals. The higher the value" the greater the proportion of a

useful signal" on the other hand also reversed. %t some point Ec4Ioig" there are two possiilities. 2irst" the Ec is very large"

dominant level here" Ec" Io is very small" that is to say here is

from another ase stationNs messy little pilot signal" Ec4Io also

larger. In the latter case is wea)" ecause the Ec small" Io is also

small" so small" so /SSI also there may e dropped. %t some point

Ec4Io also small" there are two possile" rst" the Ec is also small

small /SSI" this is the wea) coverage area. The Ec is not small"

/SSI" this illustrates the Io is the overall intensity of the signal isnot ad. This situation is often a 3SC switch data conguration" no

neary strong pilot signal into the adacent community tale" so

the phone doesnNt recogni?e the strong pilot signal in the vicinity

as a amming signal processing. 8n the road" in the case of a

typical phenomenon is the phone in a move to maintain certain

/SSI" Ec4Io level" rapid rise to 2E/ and eventually dropped.

> T;PE7R

TA8JE/ is the phoneNs transmitter power. Je )now that powercontrol is guaranteed call !uality and address the C@M%

community interference tolerance and one of the )ey means of

moile phone from the ase station near" uplin) !uality

good" the moile phone transmitting power is smaller" ecause at

the ase station is ale to guarantee the reception of the signal to

launch moile phone and fer also small and moile phones

transmitting power is smaller to other moile phones in the

community is also a small interference. So moile phonestransmit power level" reFecting the handsetNs current uplin) loss

and interference. Oplin) loss of large" or there is serious

interference with the phoneNs transmitter power will e greatly

missed moile phone transmitting power is smaller. /oadtest" in

normal circumstances" the more closer to the ase station or



/epeater" the moile phone transmitting power is reduced" away

from the ase station and /epeater" the moile phone

transmitting power increases. If the ase station and /epeater

neary moile phone transmitting power" oviously it is not

normal. erhaps there is interference" the uplin) can e a asestation and /epeater itself. Such as community antenna wrong

receive carrier fre!uency amplier circuit prolems" etc. If the

/epeater neary" cell phone transmitter power" it may e a

/epeater malfunctions" uplin) gain set too small" and so on.%ove

you can see" the road ofTA8JE/ level reFects the ase

station coverage area of reverse lin) !uality and uplin)

interference levels.

-R;PE7R/A8JE/ is a moile phone to receive power. In C@M%" according

to my personal understanding" there are three parameters is very

close y" you can almost e!uivalent to the use of parameters.

#amely /A8JE/" /SSI" Io. /A8JE/ is a moile phone to

receive power" Io is moile phones currently receives all signal

strength" /SSI is receives downlin) and of total power" as

currently I have access to information" the title eDplains" ut

understanding is very similar" is the phone receives a total ofsignal strength. /A8JE/ and reFects the current signal

receiving phone" /A8JE/ small area" the wea) positive fall

within the coverage area" /A8JE/ places elong to the covered

area. 3ut the high places" /A8JE/ and does not necessarily

signal !uality is good" ecause there may e no signal" leading to

fre!uency" or too many strong pilot" pilot fre!uency pollution.

Therefore" the analysis of /A8JE/ to Ec4Io to analysis.%ove

you can see" /A8JE/ and simply reFects the drive testsignal coverage area" rather than the !uality of the

signal coverage.

T;A:J

TA%@] reFects the up and down*lin) a alance. #ote that this

value is calculated from the measurement" instead. 6&&M C@M%



system is TD[adust R <-d3 B TD[power B /D[power" 5(&&M

C@M% is TD[adust R <+d3 B TD[power B /D[power.

TA%@] reFects the current location of the moile uplin) and

downlin) of a more mass. Je )now that under normal

circumstances" the cell phone away from the ase station close tothe phoneNs transmitter power will decrease" and

received power will ecome larger and far away from the cell

phone" moile phone ase station transmitter power will increase

while receiving power gets smaller. #ormally" the transmitter

power and receiver power plus a constant Ded values" the result

should e a small interval for eDample"*5& to B 5&;. If TA%@]

great" it means that the phoneNs transmitter power" receive the

power" then it is ovious that moile current downlin) of good!uality receiving power;" and the poor !uality of the uplin)

transmitter power;" this time forward lin) is etter than a reverse

lin). 8n the contrary" TA%@] is very small" eDplains this reverse

lin) well to the forward lin). Je )now that the ase station

coverage depends on the reverse lin) loss level. Therefore" in

General" we re!uire the following TA%@] in &. 3ut greater than 5&"

the reverse lin) forward lin) than are poor" the situation is not

ideal. 2or TA%@]" nor can they e said to e as small as possile.3ut in the actual drive test" we generally encounter" often TA%@]

too high" forward lin)" reverse lin).

, 7R

2E/ is a forward*fer. 2orward fer with Ec4Io also is a

comprehensive !uality of forward lin). 3ecause when the phone is

in the multi*channel soft switching" fer actually multi*channel

forward an integrated signal !uality. 2E/" description of themoile phone of the forward lin) etter" received signal is good"

this time Ec4Io also should e etter. The larger the @escription

cell phone 2E/ the received signal strength is poor" Ec4Io should

also at this time. 2E/ is large" it may also e due to a neighoring

community switch parameter conguration error. If you switch



etween adacent communities with lea)age" single and moile to

moile" adacent to the pilot was not recogni?ed" and the pilot

does not recogni?e" it will ecome interference signal" resulting in

increased 2E/. In reality" often manifested in moile" moile

phones" 2E/ a rapid rise in sharp decline" Ec4Io" and nallydropped. %ove that is closely followed y Ec4Io 2E/. 2E/

reFects the call !uality is good or ad" reFects the /oad Test

regional coverage !uality level" rather than the signal coverage

strength level. In some areas although elonging to the wea)

signal coverage area" ut relatively clean messy signals" noise;"

as well as e good 2E/.

#ote the aove parameters" Ec4Io" /A8JE/ is the phone in

standy or call have parameters" TA8JE/" TA%@]" 2E/ is only aphone call and from the only parameter. The aove ve

parameters" together" to analysis of drive test region to cover the

intensity level" the former to override the !uality level" as well as

the reverse lin) loss level" and so on" is the analysis of drive test

is the most important parameters. In*depth understanding of the

ve parameters" comined with the overall situation for drive

testing specic analysis" is engaged in networ) optimi?ation staH

in one of the asic conditions.

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