very important dt,opt,plannning doc

8/13/2019 Very Important DT,OPT,Plannning Doc

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GSM BASIC CONCEPT

Timing Advance With Calculation

A Timing Advance (TA) is used to compensate for the propagation delay as thesignal travels between the Mobile Station (MS) and Base Transceiver Station(BTS). The Base Station System (BSS) assigns the TA to the MS based on how faraway it perceives the MS to be. Determination of the TA is a normally a functionof the Base Station ontroller (BS)! bit this function can be handled anywhere inthe BSS! depending on the manufacturer.

Time Division Multiple Access (TDMA) re"uires precise timing of boththe MS and BTS systems. #hen a MS wants to gain access to thenetwor$! it sends an access burst on the %A&. The further away the MSis from the BTS! the longer it will ta$e the access burst to arrive at theBTS! due to propagation delay. 'ventually there comes a certain point

where the access burst would arrive so late that it would occur outsideits designated timeslot and would interfere with the net time slot.

Access Burst

As you recall from the TDMA Tutorial! an access burst has *.+, guardbits at the end of it.

This guard time is to compensate for propagation delay due to the un$nowndistance of the MS from the BTS. -t allows an access burst to arrive up to *.+,bits later than it is supposed to without interfering with the net time slot.

*.+, bits doesnt mean much to us in the sense of time! so we must convert *.+,bits into a frame of time. To do this! it is necessary to calculate the duration of a
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!sin" the speed of li"ht, we can calculate the distance that aradio wave would travel in a "iven time frame The speedof li"ht #c$ is %&&,&&& km's

So, we can determine that a MS could theoretically be up to(5)km away from a BTS when it transmits its access

burst and still not interfere with the next time slot

*owever, we must take into account that the MS synchroni+eswith the si"nal it receives from the BTS e must accountfor the time it takes for the synchroni+ation si"nal totravel from the BTS to the MS hen the MS receives thesynchroni+ation si"nal from the BTS, it has no way ofdeterminin" how far away it is from the BTS So, when theMS receives the syncroni+ation si"nal on the S-*, itsynchroni+es its time with the timin" of the system

*owever, by the time the si"nal arrives at the MS, thetimin" of the BTS has already pro"ressed someTherefore, the timin" of the MS will now be behind thetimin" of the BTS for an amount of time e.ual to thetravel time from the BTS to the MS

/or example, if a MS were exactly (5)km away from the BTS,then it would take 252s for the si"nal to travel from theBTS to the MS
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The MS would then synchronize with this timing and send its access burst on theRACH. It would take 22!s "or this signal to return to the #TS. The total roundtri$ time would be %&!s. So' by the time the signal "rom the MS arri(es at the#TS' it will be %&!s behind the timing o" the #TS. %&!s e)uals about *+,.bits.

The ,-.2 bits o" guard time would absorb some o" the delay o" *+,. bits' butthe access burst would still cut into the net time slot a who$$ing ,-.2bits.

Maximum Si+e of a -ell

-n order to compensate for the two8way trip of the radio lin$! we must divide themaimum delay distance in half. So! dividing 0,.$m in half! we get
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approimately 20.* $m. -f a MS is further out than 20.*$m and transmits anaccess burst it will most li$ely interfere with the following time slot. Any distanceless than 20.*$m and the access burst should arrive within the guard timeallowed for an access burst and it will not interfere with the net time slot.-n SM! the maimum distance of a cell is standardi9ed at 2,$m. This is due

mainly to the number of timing advances allowed in SM! which is eplainedbelow.

*ow a BSS 0etermines a Timin" 1dvance

:or each 2.45s of propagation delay! the TA will be incremented by ;. -f thedelay is less than 2.45s! no ad


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The 0istance of a Timin" 1dvance

#hen calculating the distances involved for each TA! we must remember that the

total propagation delay accounts for a two8way trip of the radio wave. The first legis the synchroni9ation signal traveling from the BTS to the MS! and the secondleg is the access burst traveling from the MS to the BTS. -f we want to $now thetrue distance of the MS from the BTS! we must divide the total propagation delayin half.

:or eample! if the BSS determines the total propagation delay to be 2.45s! wecan determine the distance of the MS from the BTS.

#e determined earlier that for each propagation delay of 2.45s the TA isincremented by one. #e


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The TA becomes very important when the MS switches over to using a normalburst in order to transmit data. The normal burst does not have the *.+, bits ofguard time. The normal burst only has *.+, bits of guard time! so the MS must

transmit with more precise timing. #ith a guard time of *.+, bits! the normalburst can only be received up to 21.==5s late and not interfere with the net timeslot. Because of the two8way trip of the radio signal! if the MS transmits morethan ;,.++5s after it is supposed to then it will interfere with the net time slot.

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Hi

Hi All Thanks all "or your mails./ow we are co(ering 0SM basic and 20 o$timization and C1MA basics.

Soon we are going to start a blog o" +0 and wima basics.Ho$e all o" you will enoy these blogs also.

/eed 3our suggestions to make it better.
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kee$ mailing

cellular.$lanning.o$timization4gmail.com0 comments Links to this post

FREQUENCY HOPPING

What is Frequency Hopping?

:re"uency &opping is an old techni"ue introduced firstly in military

transmission system to ensure the secrecy of communications and combat %eported values of rlev are more concentrated around mean.
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2 3nterference 1vera"in"

-nterference Averaging means spreading raw bit errors (B'% caused by theinterference) in order to have random distribution of errors instead of havingburst of errors! and therefore! enhance the effectiveness of decoding and de8

interleaving process to cope with the B'% and lead to better value of :'%.

#ith hopping! the set of interfering calls will be continually changing and theeffect is that all the calls eperience average "uality rather than etremesituations of either good or bad "uality. All the calls suffer from controlledinterference but only for short and distant periods of time! not for all the durationof the call.

> :or the same capacity! :re"uency &opping improves "uality and for a givenaverage "uality :re"uency &opping ma$es possible increase in capacity.

> #hen more than 2 ? of the reports have r"ual of or 0 then voice "ualitydisturbances start to appear.

> ains (reduction in the 3- value needed to satisfy the "uality re"uirementsinvolved in the criterion) from hopping relative to fied fre"uency operation canbe achieved.

;32 interference@ ; dB gaini.e. if ; out of 2 fre"uencies are eperiencing a continuous interference a gain of ;dB in 3- re"uirement is obtained.

Similarly!;3= interference@ = dB gain;3, interference@ dB gain+3= interference@ 1 dB gain+3, interference@ = dB gain

The effective gain obtained with :re"uency &opping is due to the fact that theinterference effect is minimi9ed and it is easier to $eep it under control.

!ypes of Frequency Hopping

There are two ways of implementing :re"uency &opping in a Base StationSystem! one referred as Base Band :re"uency &opping (BB&) and another asSynthesi9er :re"uency &opping (S:&). Their operation differs in the way theyestablish the Base to Mobile Station lin$ (downlin$)! however there is not

difference at all between Mobile Station to Base Station lin$ in both types ofhopping. Motorola does not allow BB& and S:& to be used together on the samesite

Base Band /re.uency *oppin"

This is accomplished by routing the traffic channel data through fied fre"uencyD%s via the TDM highway on a timeslot basis. -n this case! the D% would


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have fied tuned transmitters combined either in low loss tuned combiners orhybrid combiners.

> D% always transmits fied fre"uency.> The information for every call is moved among the available D%s on a per

burst basis. (Burst of ,00 5s)> all hops between same timeslots of all D%s.> rocessing (coding and interleaving) is done by digital part associated with D%

on which call was initially assigned.> :or uplin$ C call is always processed by D% on which the call was initially

assigned.> 6umber of D%s needed is e"ual to the number of fre"uencies in the hopping

se"uence.> B& fre"uency can be included in the hopping se"uence.> ower control does not apply to B& or bursts transmitting B& fre"uency.> B&! timeslot 1 will never hop.> Any timeslot with & will never hop.> Timeslot carrying all SD&s can hop.

-f a networ$ running with fied fre"uency plan is switched over to BB& (B&included in MA list) without any fre"uency changes! significant "ualityimprovement can be observed in the networ$. As a result drop call rate reducesin the networ$. Alternatively! for the eisting networ$ "uality additional capacitycan be provided. :&- can be used effectively in BB&. :urther details regarding:&- planning are discussed later in the document.

2 Synthesi+er /re.uency *oppin"

This is accomplished by high speed switching of the transmit and receivefre"uency synthesi9ers of the individual D%s. As a result of dynamic nature ofthe transmit fre"uency! broadband (hybrid) combining of the transmitters isnecessary.

> D% changes transmitting fre"uency every burst.> all stays on the same D% where it started.> %emote tune combiners (%T) are not allowed.> 6umber of D%s is not related to number of fre"uencies in hopping se"uence.> B& can be included in the hopping se"uence@

1. -f B& is included in the hopping se"uence! timeslots ; to 0 can not be

used to carry traffic. They transmit dummy burst when B& fre"uency isnot in the burst. #henever B& fre"uency is being transmitted in aburst by D%! it will be transmitted at full power.

2. B& D% will never hop. -t either carries traffic in timeslots ; to 0 or ittransmits dummy bursts.

> Transmission and reception is done on the same timeslot and same D%.


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Frequency Hopping Para"eters

SM defines the following set of parameters@

Mobile 1llocation #M1$4Set of fre"uencies the mobile is allowed to hop over.

Maimum of 2 fre"uencies can be defined in the MA list.

*oppin" Se.uence umber #*S$4Determines the hopping order used inthe cell. -t is possible to assign = different &S6s. Setting &S6 1 providescyclic hopping se"uence and &S6 ; to 2 provide various pseudorandomhopping se"uences.

Mobile 1llocation 3ndex 6ffset #M136$4 Determines inside the hoppingse"uence! which fre"uency the mobile starts to transmit on. The value of MA-Eranges between 1 to (68;) where 6 is the number of fre"uencies defined in theMA list. MA-E is set on per carrier basis.

Motorola has defined an additional parameter! :&-.

/re.uency *oppin" 3ndicator #/*3$4Defines a hopping system! made up byan associated set of fre"uencies (MA) to hop over and se"uence of hopping(&S6). The value of :&- varies between 1 to 2. -t is possible to define all = :&-sin a single cell.

Motorola system allows to define the hopping system on a per timeslot basis. Sodifferent hopping configurations are allowed for different timeslots. This is veryuseful for interference averaging and to randomi9e the distribution of errors.

7SM al"orithm

SM has defined an algorithm for deciding hopping se"uence. The algorithm isused to generate Mobile Allocation -nde (MA-) for a given set of parameters.

A%:6@ absolute radio fre"uency channel numberMA@ mobile allocation fre"uencies.MA-E@ Mobile allocation offset (1 to 68;)! where 6 is the number of fre"uencies

defined in MA.&S6@ &opping se"uence number (182)T;@ Super frame number (18+1=0)T+@ T& multiframe number (18+,)T2@ Signaling multiframe number (18,1)

This algorithm generates a pseudorandom se"uence of MA-s. MA- along withMA-E and MA will decide the actual A%:6 to be used for the burst.


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8lannin" for /re.uency *oppin"

/re.uency 8lan4

:re"uency &opping plan differs from the conventional fied fre"uency plan. Theplan depends upon the type of :re"uency &opping system used. -n case of S:&including B& fre"uency in hopping se"uence is not a practical option! as itresults in loss of traffic channels on B& carrier. A separate fre"uency plan isprepared for the B& carriers. This planning is very much similar to theconventional fied fre"uency plan with lesser number of fre"uencies. This planneeds to be done very carefully as the system monitors cells based on the B&fre"uency only. Since B& carrier radiates continuously without downlin$

power control! fre"uencies used for B& on one cell should not be used ashopping fre"uencies on other cell. The reason is to avoid continuous interferencefrom B& carriers. The benefits of hopping increase if more fre"uencies areavailable for hopping. enerally the fre"uency band is divided into two parts! oneused for B& fre"uency plan and other for hopping fre"uencies. The division offre"uency band for allocation of B& and hopping carriers should be done tomaintain reasonable 3- for B& carriers as well as to have enough fre"uenciesfor hopping.

e.g. consider a networ$ with 2; fre"uencies! using ;+ fre"uencies for B& andusing ;* for hopping with ; fre"uency as guard! is the ideal option. But it may notbe practically possible to plan B&s with ;+ fre"uencies (=3;+ reuse). sing ;,for B& plan and ;, for hopping fre"uencies is more practical. There alwayseists a trade8off between B& and hopping plans. sing very less fre"uenciesfor B& plan might result in poor "uality on B& carrier and the advantagesof having "uality improvement on hopping carriers may be lost.

-n case of BB&! generally B& carrier is included in the hopping se"uence. Thebenefits of BB& can be obtained only when most of the sites in the networ$ arehaving more than one 6B& carriers. Benefits of BB& comparable to S:& canonly be obtained by e"uipping additional hardware in order to include morefre"uencies in hopping se"uence. &owever BB& without additional hardwarewill result in "uality improvements and provide scope of additional capacity as

compared to fied fre"uency plan though the benefits may not be as significant asseen in S:&.

2 8lannin" of *S4

&S6 allocation to the cells is done in random fashion. Farious scenarios areeplained below@


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a. MA list is same for all the cells of the site C -n this case &S6 is $ept same for allthe cells of the site. MA-E is used on per carrier basis to provide offset forstarting fre"uency in hopping se"uence and avoid hits among carriers of the site.ractically it is possible to achieve 1? hit rate within the site! as all the cells of the

same site are synchroni9ed.b. MA list is same for the cells of different sites C -n this case &S6 should bedifferent for all such cells. MA-E can be same or different in this case as &S6 isdifferent.

c. MA list is different for the cells C -n this case &S6 planning is not important! asthere can not be any hits between these cells.

d. &S6 is set to 1 C This is the case of cyclic hopping. The se"uence for hoppingremains same and is repeated continuously. This is not recommended in theurban environment where fre"uency reuse is more. This is because the networ$ isnot synchroni9ed so if there is any one hit it will result in continuous se"uence ofhits. yclic hopping is preferred in rural environment as it provides themaimum benefits of fre"uency diversity.

% 8lannin" of M1364

The benefits of MA-E planning can be best achieved only in case when sectorshaving same MA list are synchroni9ed. :or non8synchroni9ed sectors MA-E canbe the same. -n the present version (S%+)! Motorola does not provide manualMA-E setting. -t is set automatically by the system. &owever from S%2onwards it will be possible to set MA-E manually. -t has to be changed on a caseto case basis. -n cases where there are large numbers of hits! MA-E change canbe very effective as it adds the offset in the hopping se"uence and hitrate can be

reduced.

9 8lannin" of /*34

This parameter is not specified in SM. :&- is the Motorola defined hoppingsystem. -t actually means an independent hopping system consisting of MA and&S6. Total of = such hopping systems can be set in a cell.:&- can be defined on a timeslot basis.

e.g. consider a cell with 2 carriers i.e. + carriers are hopping. -t is then possibleto define = different :&-s for ; timeslots. That means timeslot 1 to 2 of ; carriercan have one :&- and so on.

Benefits and Drawbac$s of :&-

> Separate :&- can be defined even for each carrier with separate MA list.


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> :or a fully utili9ed cell! :&- can be used to control increase in hitrate during pea$hours. This can be done by defining different MA list associated with a :&- forone of the carriers.

> Main benefits of :&- can be obtained in BB&. onsider a cell with + carriersusing BB& with B& included in the hopping se"uence. Timeslot 1 of B&

will not hop. A separate :&- (with MA list without B& fre"uency) has to bedefined for timeslot 1 of 6B&.> Different :&-s in the same cell is not used etensively in Motorola networ$s with

S:&! where B& fre"uency is not included in hopping se"uence.> Ene drawbac$ of using :&- on timeslot basis is that it adds more compleity to

the database.

5 :euse pattern for hoppin" carriers4

onventionally there are 2 main reuse patterns followed for hopping fre"uencies.

; 4-t means all the cells in the networ$ use the same fre"uencies for hopping.e.g. -f ;, fre"uencies are to be used for hopping! then every cell will have all ;,fre"uencies in the MA list. This type of reuse is useful in urban areas! wherecapacity re"uirement is large. &owever there is very less planning involved andso less control over "uality problems.

% ;


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-all setup4 -n call setup! SD& hopping is also possible. There are noseparate settings re"uired for SD& hopping. b Since S%2 allows control overSD& configuration (location of SD& on timeslot basis)! SD& hoppingdepends on the location of SD&. -n case of S:& (with B& not included inMA list)! if SD&s are on B& carrier they will not hop whereas SD&s on

6B& carriers may hop. enerally it is preferred to $eep SD&s on hoppingcarriers as they have better 3- compared to B& carriers. all success rate willdepend on the cleanliness of B& carriers.

/rame =rasure :ate #/=:$4 :'% indicates the number of TDMA frames thatcould not be decoded by the mobile due to interference. This parameter gives theindication of hitrate. :'% improves (gain of to * dB) after implementation offre"uency hopping.

( Tools for simulation and drive test4Motorola uses a tool G&andsemHwhich can simulate S:& plan (different reuse patters and &S6 plan). Iatestversions of pla6'T and olf are supposed to support :re"uency &oppingsimulation. Drive test tools that display decoded layer 2 information are used formonitoring fre"uency hopping networ$s. T'MS is one of the drive test tools thatcan be used for the purpose.

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TDMA

Time Division Multiple Access(TDMA) is a technology for

shared medium (usually radio) networks. It allows several

users to share the same frequency by dividing it into

different time slots. The users transmit in rapidsuccession, one after the other, each using their own

timeslot. This allows multiple users to share the same

transmission medium (e.g. radio frequency) whilst using

only the part of its bandwidth they require. Used in the

!", #$% and i$&' digital cellular standards, among others.

T$" is also used etensively in satellite systems, local

area networks, physical security systems, and combat*net

radio systems.

The name +TDMA+ is also commonlyused in merica to refer

to a specific second generation () mobile phone standard,

moreproperlyreferred to as I!*-/ or $*"#!, which usesthe T$" technique to timeshare the bandwidth of the

carrier wave.

The two different uses of this term can be confusing. T$"

(the technique) is used in the !" standard. 0owever, T$"

(the standard, i.e. I!*-/) has been competing against !"

and systems based on %$" modulation for adoption by the
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Initial synchronisation of a phone requires even more care.

3efore a mobile transmits there is no way to actually know

the offset required. 4or this reason, an entire timeslot

has to be dedicated to mobiles attempting to contact the

network (known as the 5%0 in GSM). The mobile attempts to

broadcast at the beginning of the timeslot, as received

from the network. If the mobile is located net to the base

station, there will be no time delay and this will succeed.

If, however, the mobile phone is at 2ust less than 6km

from the base station, the time delay will mean the

mobile7s broadcast arrives at the very end of the timeslot.

In that case, the mobile will be instructed to broadcast

its messages starting a whole timeslot earlier than would

be epected otherwise. 4inally, if the mobile is beyond the

6 km cell range in !", then the 5%0 will arrive in a

neighboring time slot and be ignored. It is this feature,

rather than limitations of power which limits the range of

a !" cell to 6 kilometers when no special tricks areused. 3y changing the synchroni1ation between the uplink

and downlink at the base station, however, this limitation

can be overcome.

In radio systems, T$" is almost always used alongside

4$" (4requency division multiple access) and 4$$

(4requency division duple)8 the combination is referred to

as 4$"9T$"94$$. This is the case in both !" and I!*-/

for eample. The eceptions to this rule include :%$"*T$$

which combines 4$"9%$"9T$" and T$$ instead.

Advantage of TDMA

ma2or advantage of T$" is that the radio part of

the mobile only needs to listen and broadcast for its

own timeslot. 4or the rest of the time, the mobile

can carry out measurements on the network, detecting

surrounding transmitters on different frequencies.

This allows safe inter frequency handovers, something

which is difficult in %$" systems, not supported at

all in I!*;6 and supported through comple system

additions in U"T!. This in turn allows for co*

eistence of microcell layers with macrocell layers.

3ut, %$" supports +soft hand*off+ which allows a

mobile phone to be in communication with up to / base

stations simultaneously, a type of +same*frequency


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handover+. The incoming packets are compared for

quality, and the best one is selected. This enables

%$" to perform in areas where T$" calls would be

dropped.

Disadvantage of TDMA

disadvantage of T$" systems is that they create

interference at a frequency which is directly

connected to the time slot length. This is the

irritating bu11 which can sometimes be heard if a !"

phone is left net to a radio. nother disadvantage

is that the +dead time+ between time slots limits the

potential bandwidth of a T$" channel. This is why

early efforts to incorporate timeslots into U"T!

failed, leaving U"T! as a purely %$" technology. Theonly country to continue pursuing T$*!%$" (time

division synchronous %$") is mainland %hina, because

the government does not want to pay patent royalties

to


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Timer Name Description Value

T0* Re!easetimer

Time the net4or" 4aits after senin% a RELEASEmessa%e ,nti! recei(in% a RELEASE &OM:LETEmessa%e+ This occ,rs #efore re-transmittin% theRELEASE or re!easin% the Mo#i!it$ Mana%ement

connection+

10 secons

T10 &a!!proceein% timer

Time the net4or" 4aits after recei(in% a &ALL&ONIRMED messa%e ,nti! recei(in% a ALERTING9

&ONNE&T9 or DIS&ONNE&T messa%e #efore initiatin%c!earin% proce,res to4ars the MS+

10 secons

T1 &onnectac"no4!e%e timer

Time the net4or" 4aits after transmittin% a &ONNE&Tmessa%e ,nti! recei(in% the &ONNE&T A&KNO;LEDGEmessa%e #efore performin% c!earin% proce,res 4ith the

MS+

10 secons

T. Moif$comp!ete timer

Time the net4or" 4aits after senin% a MODI< messa%e,rin% ca!! moe chan%es9 ,nti! recei(in% a MODI hec$ cell parameter MAQTA and TAI-M. -f it covers far coverage! it ispossible to setting of the cell parameters MAQTA and TAI-M to ahigher value (for e.g. MAQTA2! TAI-M+)

> -f the cell is really covering far away from the site! other options are

reducing the coverage by down tilting the antennas! reducing antennaheight! changing antenna or reducing output power

> -f it is a rural area and need to cover a larger area! 'tended %angefeature might be useful to be considered.

6ther :eason
http://cellular-planningoptimization.blogspot.com/2010/02/steps-for-dt.htmlhttp://cellular-planningoptimization.blogspot.com/2010/02/excessive-timing-advance-ta.htmlhttp://cellular-planningoptimization.blogspot.com/2010/02/steps-for-dt.htmlhttp://cellular-planningoptimization.blogspot.com/2010/02/excessive-timing-advance-ta.html


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Drop due other reason e"ual to total number of drops subtracts all drops withreason. -f any of the above drop reason didnNt meet the criteria! the reason fordrop will be in the OEther %easonN.

Probable Reason

H/W fault Hardware Problem (Managed Object in B!"

#isturbance $in%/ ransmission disturbance &roblem

Parameter !etting Wrongl' defined setting (for e.g. $) * $ocation rea )ode"

Mobile !tation M! &roblem

+nterference +nterference &roblem (,&lin%"

&ow to analy9e@

-)ec% te B! error log for ardware faults. (run commands R0$P R0M3P to loo%te ardware faults log"

-)ec% if +)M is indicating u&lin% interference in te cell.

-)ec% wit OM regarding transmission &roblems4 HW &roblems and ser5ice affectingmaintenance wor% during te time &eriod. e a5erage cell downtime and )H

a5ailabilit' sould also be cec%. +t migt be intermittent lin% connection.

-)ec% object t'&e MO!4 wic is based on dro& on imeslot (!" in order to find fault'de5ices.

Congestion Analysis

This is second topic for today that is Wongestion AnalysisW a well $nown

word for Telecom professionals .

Traffic congestion is one of the ma ;@ Short term growth
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-f the high traffic related to an occasional event! li$e sports event! fairs!conference! a temporary solution might be considered.

> +@ Iong term growth

-f there is a long8term growth the networ$ capacity has to growaccording to the demand.

Type of Congestion

The congestion analysis begins by identifying if there is only SD& orT& congestion or both. ongestion on both SD& and T& maymean that the only way to get rid of the congestion is to add morephysical capacity in terms of transceivers or sites.

onsider how many channels that are allocated in the cell. -f possible!epand the capacity with new transceivers! otherwise a new site must beimplemented. :re"uency planning schemes such as M% and :I could

be used to relieve congestion. Microcells could be used to ta$e traffic insevere congested areas.

SDCCH Congestion

-n %*! the time congestion should be used instead of congestion based

on access attempts as there is no way to estimate the number of accessattempts a single mobile does.

The flowchart below! eplains a general approach to investigate SD&ongestion. The net section describes the action points in thisflowchart. The reference to each action point is indicated on the flowchart as well.


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Low Signal Strength Analysis

lets starts todays topic that is Iow signal strength analysis #hat could be the probable cause of low signal while you drive oroptimi9e.:irst see the following flow chat and try to understand the things

Remember that

Low Signal strength is one of the reason of drop call. Itcan be indicated by many calls disconnected at low
http://cellular-planningoptimization.blogspot.com/2010/02/low-signal-strength-analysis.htmlhttp://4.bp.blogspot.com/_6eWNrxMtTHk/S4K8MEsDYfI/AAAAAAAAAC0/7cN7kKqQRXo/s1600-h/low+coverage.JPGhttp://1.bp.blogspot.com/_6eWNrxMtTHk/S4LEeM0oeRI/AAAAAAAAAC8/hA4BkhfglJM/s1600-h/con1.JPGhttp://cellular-planningoptimization.blogspot.com/2010/02/low-signal-strength-analysis.html


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signal strength by subscriber, drop calls due toexcessie T!, poor handoer performance and poor callsetup performance."hat could be the probable reasons

Probable Reason

Poor B!)

'changeropertysetting

&igh IE#SSDI IE#SSIwill give more drop reason dueto SS and this might not showthe actual drop. -t is because

drop due to SS is more prioritythan Kuality.

6o dominant

cell

ell might be isolated or

standalone.

Antenna tilt orientation

Too much downtilt sometimesmight not cover a larger areaand the subscriber might lose

the SS.

Eutput ower Iow output power might causesmaller border cell.

#ust try to obsered what could be the right cause $%

The following procedure should be performed for lowsignal strength

analysis$

1:

-dentify the baseline re"uirement of design and BS echange property

(setting for IE#SSI3IE#SSDI).

+@

hec$ the value for IE#SSDI IE#SSI. -f it is higher thanAM-6! change the parameter to a reasonable value since the dropreason will be more priority to SS compared to Kuality.


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2@

hec$ the site position! antenna direction! position etc. This is to ensurethe possible location is open to interference (open water environment)or isolated. ood map is needed for this.

=@

hec$ if the site is sectori9ed or Emni. -f it is Emni! set the cell intosectori9ed cell.

,@

hec$ if the signal strength is uplin$ or downlin$ limited. Mostly! -t isdesigned to be downlin$ limited.

@

hec$ the coverage cover epected area from the planet. -f it is not!chec$ the antenna tilt and orientation. hange the direction or tilt if it istoo much downtilt or pointing to a wrong direction.

0@

Sometime! low output power might cause low SS. hec$ output power

and if it is low! increase the output power.

*@

hec$ cell whether it has hotspots from drivetests. -f found! adding newsite is recommend.

4@

-n order to chec$ power distribution! run ell Traffic %ecording (T%)to that particular cell.

;1@

hec$ if the cell has indoor coverage problem. -f yes! add micro siteinstead.

TCH Drop Analysis
http://cellular-planningoptimization.blogspot.com/2010/02/tch-drop-analysis.htmlhttp://cellular-planningoptimization.blogspot.com/2010/02/tch-drop-analysis.html


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:adio @ink TimeA6ut

'very time a SA& message can not be decoded the radio lin$ time8out counter is decreased by ;. -f the message can be decoded the counteris incremented by +. &owever! the value can not eceed the initial value.

The initial value is set by the parameter %I-6/T for radio lin$ time8outin the mobile station and by %I-6/ for timeout in the BS. -f themobile moves out of coverage and no measurement reports are receivedin the BS! there will be a radio lin$ time8out and the message hannel%elease (cause@ abnormal release! unspecified) is sent to the mobilestation and the SA& is deactivated in the BTS. A lear %e"uestmessage is sent to the MS. To be sure that the mobile has stoppedtransmitting! the BS now waits %I-6/T SA& periods before thetimeslot is released and a new call can be established on the channel.

2 @ayer 2 TimeA6ut

-f the BTS never get an ac$nowledge on a Iayer + message after the timeT+11Q6+11! the BTS will send 'rror -ndication (cause@ T+11 epired)to the BS! which will send hannel %elease (cause@ abnormal release!timer epired) to the mobile station and a lear %e"uest to the MS.The SA& is deactivated and the BS waits %I-6/T SA& periods

before the timeslot is released and a new call can use the channel. This isonly valid if the call is in steady state! i.e. not during handover orassignment.

% :elease 3ndication

#hen the BTS received a layer + D-S frame from the mobile it replieswith a Iayer + A frame to the mobile station and a %elease -ndicationto the BS. The system does only react on %elease -ndication if it isreceived during a normal disconnection situation. -f such a message isreceived unepectedly this will usually cause radio lin$ time8out ortimer T+11 epiration as the mobile station stops the transmitting ofmeasurement reports. -t is also possible that the release will be normaldepending on when the %elease -ndication is received.

9 MS- TimeA6ut6ormal %elease@


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-f the MS never received a response on a message (e.g. -dentity%e"uest) and there is no radio lin$ time8out or layer + time8out! theMS will send a lear ommand to the BS. The time8out is dependingon the message. #hen receiving lear ommand! the BS will send ahannel %elease (cause@ normal release) and then deactivates theSA&.

%e


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The T& Drop counters due to 'cessive Timing Advance will peggedwhen the during the time of disconnection! the last Timing Advancevalue recorded was higher than the TAI-M arameter. This drop reasonis commonly apparent to isolated or island sites with a wide coveragearea.

1ction4hec$ if the cell parameter TAI-M is X W2W Solution4Set TAI-M to a value close to 2.Tilt antenna3reduce antenna height3output power! etc. for co8channelcells.

T-* 0rop :easons #2$@ow Si"nal Stren"th on 0own or !plink or Both @inks

The drops counters due to Iow Signal Strength will be pegged when theSignal Strength during the last Measurement %eport before the calldropped is below the IE#SSDI and3or IE#SSI Thresholds.IE#SSDI and IE#SSI are BS 'change roperty parameters

which is used only for statistics purposes and does not affect thebehavior of calls. -f both I and DI Signal Strength are below thethresholds! only Drop due to Iow SS BI will pegged. 6ormally a call isdropped at the border of large rural cell with insufficient coverage. Bad

tunnel coverage cause many dropped calls as well as so called coverageholes. Bad indoor coverage will result in dropped calls. Buildingshadowing could be another reason.

1ction4hec$ coverage plots.hec$ output power.hec$ power balance and lin$ budget.hec$ if Emni site.

hec$ antenna configuration type.hec$ antenna installation.erform drive tests site survey.hec$ T%Q3TS with high E6'%%6T.

Solution4Add a repeater to increase coverage in for eample a tunnel.


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hange to a better antenna (with higher gain) for the base station.Add a new base station if there are large coverage holes.Bloc$3Debloc$ T%Q

T-* 0rop :easons #%$8oor Duality on 0own or !plink or Both @inks

The drops counters due to Bad Kuality will be pegged when the SignalStrength during the last Measurement %eport before the call dropped isabove the BADKDI and3or BADKI Thresholds. BADKDI andBADKI (epressed in DTK) are BS 'change roperty parameters

which is used only for statistics purposes and does not affect thebehavior of calls. -f both I and DI Kuality are above the thresholds!only Drop due to BAD Kuality BI will pegged.

roblem on Bad Kuality is usually associated with o8channel-nterference on B& or T&. :aulty MA-E assignment can causefre"uency collisions on co8sited cells especially on ;; %euse. 'ternalinterference is also one possible cause of problem on "uality.

1ction4hec$ 3- and 3A plots.hec$ :re"uency lan (o8B& or o8BS- roblem).hec$ MA-E! &E! &S6 parameters.hec$ :&E if correctly configured (BB or SJ).hec$ for 'ternal -nterference.erform drive tests.

Solution4hange B& fre"uency.hange BS-.hange MA-E! &E! &S6.hange :&E.

%ecord %-% or on8site :re"uency Scanning to identify source ofinterference.se available radio features.

T-* 0rop :easons #9$Sudden @oss of -onnection


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Drops due to Sudden Ioss are drops that have not been registered as lowsignal strength! ecessive timing advance! bad "uality or hardware(other) reasons! and the locating procedure indicates missingmeasurement results from the MS.

There are some common scenarios that could lead to Sudden Ioss ofconnections such as very sudden and severe drops in signal strength!such as when subscribers enter into buildings! elevators! par$inggarages! etc.! very sudden and severe occurrence of interference! MSruns out of battery during conversation! &andover Iost! BTS faults!Synchroni9ation or A8bis lin$ fault (transmission faults)! and

MS :aults.

1ction4hec$ BTS 'rror Iogs! Alarms and :ault odes.hec$ E6'%%6T per T%Q and TS.hec$ Transmission Iin$ (A8bis).hec$ for D- Slips.hec$ IAD ongestion.orrelate &andover Iost to Drops due to Sudden Ioss

Solution4:i &ardware :aults and Alarms.

%eset T%Q with high E6'%%6T.'nsure that Synchroni9ation and A8bis Iin$ are stable.hange %BIT with high D- Slips.hange E6:AT or increase Transmission apacity-nvestigate &E Iost roblem

T-* 0rop :easons #5$T-* 0rops due to 6ther :easonsT& drops due to Ether %easons are computed by subtracting the sumof drops due to 'cessive TA! Iow SS! Bad Kuality and Sudden Ioss

from the Total T& Drop ounts. Drops due to Ether %easons aregenerally associated with hardware problems! transmission lin$problems on A8bis! Ater or Ainterfaces! and sometimes &andover Iost.

1ction4hec$ BTS 'rror Iogs.hec$ Alarms and :ault odes.


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hec$ E6'%%6T per T%Q and TS.hec$ Transmission Iin$ (A8bis).hec$ for D- Slips.orrelate &andover Iost to Drops due to Ether %easons

Solution4:i &ardware :aults and Alarms.%eset T%Q with high E6'%%6T.'nsure that Synchroni9ation and A8bis Iin$ are stable.hange %BIT with high D- Slips.-nvestigate &E Iost roblem

8roblem reason of drop in S0--*

@ow Si"nal Stren"th on 0own or !plinkThe reason for poor coverage could be too few sites! wrong outputpower! shadowing! no indoor coverage or networ$ e"uipment failure.1ction@ hec$ coverage plots.hec$ output power. erform drive tests.hec$ BTS error logSolution@ Add new sites. -ncrease output power. %epair faultye"uipment.

8oor Duality on 0own or !plink

1ction@ hec$ 3- and 3A plots. hec$ fre"uency plan. erform drivetests.Solution@ hange fre"uency. se available radio features.

Too *i"h Timin" 1dvance1ction@ hec$ if the cell parameter TAI-M is X styleWfont8weight@boldPWUSolution@ Set TAI-M to a value close to 2. Tilt antenna3reduceantenna height3output power! etc. for cochannel cells.

Mobile =rror

Some old mobiles may cause dropped calls if certain radio networ$features are used. Another reason is that the MS is damaged and not

wor$ing properly.1ction@ hec$ MS fleet.Solution@ -nform operator.

Subscriber Behavior


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oorly educated subscribers could use their handsets incorrectly by notraising antennas! choosing illadvised locations to attempt calls! etc.1ction@ hec$ customer complaints and their MS.

Battery /law#hen a subscriber runs out of battery during a conversation! the callwill be registered as dropped call due to low signal strength or others.1ction@ hec$ if MS power regulation is used. hec$ if DTQ uplin$ isused.

-on"estion on T-*The SD& is dropped when congestion on T&.1ction@ hec$ T& congestionSolution@ -ncrease capacity on T& or using features li$e Assignment

to another cell! ell Ioad Sharing! &S! Dynamic &alf8%ate Allocationand :%8&% Mode Adaptation etc

HOSR Analysis

8robable :easons of Bad *andover 8erformance

AAAei"hborin" -ell :elation1ction4Add neighbor cell relation.

888Missed measurement fre.uencies in B1Alist1ction4hec$ measurement fre"uencies list.

8888ermitted etwork -olor -ode problem1ction4hec$ 6 ermitted

888* faults.1ction@ hec$ BTS error log.

888Blockin" on Tar"et -ell1ction4%emove Bloc$ing on Tager ell
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888-on"estionA high congestion might lead to dragged calls (handover performed at anot intended location) and a lot of unsuccessful handovers.1ction@ hec$ T& congestion.

888Timer =xpire 1fter MS is @ostThe MS never answers the base station.1ction@ hec$ coverage. hec$ interference.

AAA@ink -onnection or * /ailure1ction@ hec$ BTS error log. erform site visit. erform lin$performance measurements.

AAABad 1ntenna 3nstallation1ction@ erform site survey and chec$ antenna installation. hec$antenna cabling.

888Many ei"hbors 0efinedMany defined measurement fre"uencies defined (U;) will decrease theaccuracy of the mobile measurements to locate the best si servers.Many measurement fre"uencies mean few samples per fre"uency andproblem for mobiles to decode the BS-.

1ction@ hec$ number of definitions.

8880elayed *andover 0ecision

A delayed handover decision can be due to congestion in the target cell.1ction@ hec$ handover parameters.

888ron" @ocatin" 8arameter Settin"

1ction@ hec$ locating parameters.

888Bad :adio -overa"e

1ction@ hec$ coverage plots.


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888*i"h 3nterference, -oA-hannel or 1dEacentThe potential handover candidate is disturbed by interference. Eutgoinghandover due to bad uplin$ "uality may indicate interference from co8channel another MS. En the border! the "uality may be rather bad andthe signal strength low. Bad downlin$ "uality may indicate interference

from another co8channel base station.

1ction@ hec$ interference. hec$ if many handovers are performeddue to downlin$ or uplin$ bad "uality.

888:eceiver 1ntenna 8roblem or :BS * problems #incandidate cell$

1ction@ hec$ antenna installation. hec$ %BS and 'rror log ofthe target cell

8888oor 3nterAMS-'BS- *andover 8erformance

:or outer or eternal cell! wrong definitions in either MS or BS maybe reason for the problem.1ction@ hec$ inter8MS3BS handover performance.

AAA3ncorrect 0own Tilt1ction@ erform site survey and chec$ antenna installation.Solution@ orrect antenna tilting.

SD&&' S,ccess Rate Ana!$sis-No"ia S$stem-1

8ossible 4R

-nterference on B& fre"uency

SD& Bloc$ing

SD Drop on Iocation pdate

AL-f! T% or IAD :ail

faulty

'cessive TA

0ata -ollection 4R
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6D %eport 0+ to chec$ B& clearance

Alarm Iog

TA distribution 6D %eport +2+

Kuality and Iin$ Balance 6D %eport ;4, and ;4.

-nterference I and 6D ;4

SD&&' S,ccess Rate Ana!$sis-No"ia S$stem-.

8roblem 1nalysis 4;. hec$ possibility o. or Ad


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8Iow overage8 :aulty or T%Q ower nbalance8Ether @ AL-f! T% or IAD :ailSome 3mportant :eports number for okia system to analy+e theT-* drop4

88reparation 0ata 48B& lanning! 6D report 10+ (DI -nterference distribution)86D %eport +;! ;4 and Alarm (-nterference)86D %eport +1=! ;,2! ;4, ( &E fail and ath Balance)86D %eport +2+ ( overage cell)86D %eport ;2 or TKM drop per causes.

K:I Ana!$sis on No"ia s$stem-T&' rop-.

8roblem 1nalysis4;. hec$ possibility o. or Ad


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hec$ the antenna direction! position etc. This is to see whether the direction covers the right

area! open space area (this can be seen by having good and updated map)

hec$ if the site is a dragon site. -f the site is a dragon site! it might be possible to get interfered by

co8channel from far away.

hec$ the co8channel sites! if found! change fre"uency and see the result. Mostly! changing the

fre"uency will solvethe interference problem.

hec$ the -ntracell handover (normally for -ntracell handover +,? plin$ and 0,? Downlin$)

and if the variation is different from this. -ntracell handover usually indicates bad "uality and

high signal strength. Too high number of intracell handover show a bad "uality cell and if

possible! you can reduce the number of intracell handover of MAQ-&E to a smaller value based

on the channel group.

Iocate the interference from statistics based on MS reversion to old channel of total attempt.

&igh number of reversion will show that the target fre"uency might be interfered.

hec$ the statistics from Eutgoing &andover decision due to bad "uality plin$ or Downlin$

from handover decision. &igh decision of handover due to "uality will show the direction of

interference.

hec$ if the interference is uplin$ interference (this might be an interference from other MSs) by

analy9e the -M band for other band (not include band ;). -f found on -M U 2! change fre"uency.

hec$ the MS power regulation setting. -f any poor setting found! correct the parameter.

-mproper setting of MS power regulation might cause interference. The feature used to reduce the

MS power when the MS is near to the BTS and hoping that it might not interfere the uplin$.

hec$ if the fre"uency hopping on or off. -f more than ; T%! turn on the fre"uency hopping.

Turning on the fre"uency will help to reduce interference by interference averaging.

hec$ if DTQ feature is onor off. -f off! turn the DTQ feature on. This will save the battery in the

MS and reduce the interference.

-f the interference is downlin$ (causing by other BTS interference)! hec$ BTS power regulation.

-f any poor setting found! correct parameter setting.

hec$ if DTQD feature is on or off. -f off! turn the DTQ feature on. This is used to reduce

interference and decrease BTS power consumption

-f changing fre"uency or parameter cannot solve the interference for both uplin$ downlin$! it

might be eternal interference.

hec$ antenna installation! ensure that the antenna is correctly installed


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hec$ if another mobile networ$li$e AMS is near to the location.

hec$ from the statistics if there is any pattern of bad "uality reason. :or eample! for

surveillance purpose! the TF orwireless alarmsystem might be turn on during nighttime only.

-f eternal interference problem occurs! do drive test and report the usage of the fre"uency toauthorities.

T&' Assi%nment Ana!$sis

Successful assignments show the number of successful T& allocationsat call setup.

At unsuccessful assignment! the Assignment omplete message! sent bythe MS! was never received by the BTS.

The formula is defined as@

? T&

ASS-6M'6TS'SS %AT'

T:ASSAII Q ;11 ?

TASSATT

robable %eason

6o dominant servingcell

The serving cell cannot cope with theT& traffic.
http://www.cellular-planningoptimization.com/2010/02/tch-assignment-analysis.htmlhttp://2.bp.blogspot.com/_6eWNrxMtTHk/S4Aps_YMIPI/AAAAAAAAACs/ZeozBleLkRs/s1600-h/TASSR.JPGhttp://www.cellular-planningoptimization.com/2010/02/tch-assignment-analysis.html


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Severe congestion onT&

:ailing T& allocation for assignmentor handover due to congestion

Iow signal strength

for call access

The signal strength might be higher on

the B& than on the T&.

-nterference Disturbance on SD& or target T&

:aulty transceiver :aulty e"uipment

The followin" procedure should be performed for T-*1ssi"nment analysis4

;@ :or T& assignment success rate! the first thing! chec$ the T& Timeongestion.

+@ -f there is congestion on T&! it is recommend doing thedimensioning and adding T% based on carried T& traffic demand.

2@ -f there is no congestion on T&! chec$ the output power of the BTS.-f the output power is low! increase the output power.

=@ -f the output power is o$! chec$ the faulty BTS by etracting BTS

error log.

,@ -f hardware fault found! swap or repair .

8erform drivetests to check the covera"e and received :x@=

@ -f no dominant cell or similar signal strengths of a few cells foundduring drivetests! it is recommended to add BTS.

0@ -f there is no problem on the dominant cell! chec$ the interference

whether co8channel or ad


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CDMA CONCEPTS

3ntroduction To -ellular -ommunication

To provide wireless communication access to subscribers we need a pairof %: channels per active call. -n a large city with several thousandsubscribers number of channels re"uired would be so large that theycannot be accommodated on one site. Also there is a limit to availabilityof spectrum. -f an operators get a , M&9 band! then he has only +,channels to use with +, channels loaded at one site he can offer cellularservice to +111 subscribers at most. To overcome this limitation! youhave to create 9ones of coverage! which are called as cells.

-ellular Structure

ells in cellular system are heagons. The actual cell covered by a basestation ta$es a very different shape depending upon the terrainobstructions and transmitting antenna characteristics. The cells are ofdifferent si9es and shapes to cover a den sly populated area! smaller cellsare used. #here a large cells cover a low subscriber density areas. Enthe highways and main roads cell si9e is optimised to cover larger lengthof the cell along the road. This is made possible by using directiveantenna.

-ode 0ivision Multiplexin" 1ccess4A

The DMA standard allows up to ; simultaneous users in one ;.++**M&9 channel. By processing each voice pac$et with two 6 codes. -t is

virtually impossible to monitor a DMA conversation or fraudulentlyaccess 'S6s! -6s or credit card numbers.

Though there are = #alsh codes available to differentiate call andtheoretical limits are around =1 calls. The operational limitations and

"uality issues will reduce the maimum number of calls somewhatbelow this value.

-hanneli+ation Methods

The band used in DMA is *+= M&9 to *4= M&9 (,1 M&9 +1M&9 separation)
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:re"uency channel is divided into code channels ;.+, M&9 of :DMA channel is divided into = code channels.

DMA is a ode Division Multiple Access

Spread spectrum techni"ue Multiple users share the same fre"uency in one cell Same fre"uency in all the cells Ta$es advantage of Multipath apacity is soft Eperates under presence of interference

CDMA CONCEPTS-2

Spread Spectrum Techni.ue

All of the modulation and demodulation techni"ues strive to achievegreater power and3or bandwidth efficiency in a stationary additive whiteaussaian noise channel. Since bandwidth is a limited resource! one ofthe primary design ob


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e base band data since is multi&lied b' a P6 code4 wic is multi&lication of eac bit

of base band data wit te P6 code4 will result into a s&read bandwidt but te s&ectral

&ower densit' remains te same4 because before s&reading te energ' was concentratedin a small bandwidt4 now it is s&read o5er a large bandwidt. 6ow wen tis s&read

signal is transmitted it is recei5ed at te recei5er4 wit signal from oter user of te same

s&ectrum4 wic became noise for tis noise4 &lus interference from oter sources. erecei5er in tese s'stems will a5e a correlate4 wic use te re&lica of te P6 code to

e7tract te same information.

1dvanta"es of Spread Spectrum

1. s te signal is s&read o5er a large fre8uenc' band4 te &ower s&ectral

densit' is getting 5er' small4 so oter communications s'stems do not suffer

from tis %ind of communications. Howe5er te 9aussian 6oise le5el is

increasing.

2. Multi&le accesses can be deal wit4 as large number of codes can be

generated4 wic will &ermit a large number of users.

:.e ma7imal number of users is not s&ectrum or resource limited4 li%e oter

access s'stems li%e 3#M4 ere te' are onl' interference limited.

;. !ecurit' witout %nowing te s&reading code4 it is nearl' im&ossible to

reco5er te transmitted data.


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of noise and interference. En top of this the neighbour cells use thesame fre"uencies! which means no re8use. So DMA capacitycalculations should be very simple. 6o of code channels in a cell!multiplied by no of cells. But it is not that simple. Though the no of codechannels available are =! it may not be possible to use all at one time!

since DMA the fre"uency is same. Soft capacity means is that all codechannels can be sued at one time! but at the cost of "uality.

8rocessin" 7ain4

8 #"ain$ F &lo" #':$

is Spread :ate

: is 0ata :ate

/or -0M1 8 #"ain$ F &lo" #22GG&&'


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Optimization Procedures in CDMA

Optimization Procedures

This document presents in detail optimization procedure for assuring

effectively network quality. This procedure is based on Voice/ata call in

cdma!"""#1$ and ata call in %V&.

&ptimization procedure shall be performed' when installation of (T) is

completed and (T) is inter#worked with *)+. +ommercial service shall

be provided' after completion and trial service is offered' at the result of

optimization procedure.

&ptimization ,rocedures are divided into the following stages based on

operational stage.

)tage 1 : )ingle +ell -unction Test)tage ! : +luster &ptimization

)tage : )ystem &ptimization

Stage & $ Single Cell 'unction test

Stage & is for erifying whether indiidual (TS wor)s well or

not' by making a single cell function test of (T) hardware and

software.

%ssential items to be tested are as follows:

1 (T) Transmitter &utput *easurement Test

! 0nitial parameter establishment ,ilot ,2/)ystem 0/)ite

0/-requency' 2eighbor 3ist

+all &rigination and Termination Test

4 )ofter 5andoff Test/6ntenna installation check irection' Tilt'

Transmission 3ine

7 )ingle +ell +overage Test

8 2oise -loor Test

Stage * $ Cluster +ptimiation

Stage * is for testing seeral (TSs in cluster, in order to erify

the inter%wor) and performance between (TSs. )tage ! is aimed

at checking basic field functions and performance in mobile

communication system' assuring primary safety in system and network'

and verifying conditions for maintaining the best quality of call and

optimization in service aspects.

1 (asic )ervice 6rea %stablishment

! Voice +overage &ptimization

ata +overage &ptimization

4 -%9 optimization

7 Voice 5andoff &ptimization
http://cellular-planningoptimization.blogspot.com/2010/02/optimization-procedures-in-cdma.htmlhttp://rfoptimisation.blogspot.com/2009/03/optimization-procedures.htmlhttp://cellular-planningoptimization.blogspot.com/2010/02/optimization-procedures-in-cdma.htmlhttp://rfoptimisation.blogspot.com/2009/03/optimization-procedures.html


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8ata 5andoff &ptimization

)hadow 6rea &ptimizationif needed

;,ilot ,ollution 6rea &ptimzationif needed

Stage - $ System +ptimiation Completion

)tage is for verifying finally comprehensive performance in network.

%ssential tests to be performed at stage are as follows:

1 +all


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*aelength 1 $ % J &G$'#


65/66

R 3!he dB" is "erely an e)pression of po*er present in a circuit

relatie to a 4no*n fi)ed a"ount $i.e.6 / "illi*att' and the

circuit i"pedance is irreleant.8

dB"R dB" 1 /+ log $P' $/+++ "W5*att'

*here dB" 1 Po*er in dB referenced to / "illi*att

P 1 Po*er in *atts

R %f po*er leel is / "illi*att&

Po*er$dB"' 1 /+ log $+.++/ *att' $/+++ "W5*att'

1 /+ log $/'

1 /+ $+'

1 +

R !hus a po*er leel of / "illi*att is + dB".

R %f the po*er leel is / *att

/ *att Po*er in dB" 1 /+ log $/ *att' $/+++ "W5*att'

1 /+ $2'

1 2+

dB"R dB" 1 /+ log $P' $/+++ "W5*att'

R !he dB" can also be negatie alue.

R %f po*er leel is / "icro*att

Po*er in dB" 1 /+ log $/ ) /+,-9 *att' $/+++ "W5*att'

1 -2+ dB"

R Since the dB" has a defined reference it can be conerted bac4

to *atts if desired.

R Since it is in logarith"ic for" it "ay also be coneniently

co"bined *ith other dB ter"s.


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dB5"R !o conert field strength in db5" to receied po*er in dB"

*ith a 0+ opti"u" ter"inal i"pedance and effectie lengthof a half *ae dipole 5 +dBu 1 /+ log:$/+-9'$/+++'$5'5$;30+'< dB"

At =0+>H

+dBu 1 -/2 dB"

2@dBu 1 -@2 dB"

very important dt,opt,plannning doc

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