6.cs traffic cases

8/13/2019 6.CS Traffic Cases

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MODULE IV

Traffic Cases

Figure A04.09: Location Updating, type norma. M! aready regi"tered in VL#

1. The MS listens to the system information, compares the LAI with the one stored in SIMcard. When it finds the difference, it decides to do an location update

2a. The MS sends a channel reuest messa!e

2". The messa!e recei#ed "y the $TS is forwarded to the $SC. The $SC allocates a

S%CC&, if there is one idle, and tells the $TS to acti#ate it

'. The MS sends a location updatin! reuest messa!e which contains the identity of the MS,the identity of the old location area and the type of updatin!

(a.The authentication parameter is sent to the MS. If the MS is not already re!istered in thisMSC)*L+ the appropriate &L+ or the pre#iously used MSC)*L+ must "e contacted toretrie#e MS su"scri"er data and authentication parameters.

(". MS sends an answer calculated usin! the recei#ed authentication parameter.

. If authentication is successful, the *L+ is updated.

-. The MS recei#es an acceptance of the location updatin!.

a. The $TS is told to release the S%CC&

". The MS is told to release the S%CC& and switches to idle mode

%urin! the location chan!e, if the MS is "usy in call, it recei#es the information a"out the newLAI on the S%CC&. The location updatin! /a"o#e said procedure0 taes place after the call isreleased

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Figure 104.3 Location Updating, Type Normal. MS already register ed in VL.


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(B) IMSI attach:

IMSI attach is used "y the MS to notify the system that it was powered on, pro#ided it is still inthe same location area as it was when it entered the detached state.

Figure A04.(0: Location Updating, type IM!I attac).

1. The MS reuests a S%CC&

2. The system recei#es the IMSI attach messa!e from the MS

'. The MSC sends the IMSI attach messa!e to the *L+. The *L+ remo#es the IMSIdetached fla! and resumes normal call handlin! for the MS

(. The *L+ returns the IMSI attach acnowled!e messa!e to the MSC

. The MS also recei#es an acnowled!e messa!e

This procedure is to "e used only when the IMSI detach fla! is set in the *L+. If the fla! is setin the &L+, switchin! to acti#e mode reuires a normal location updatin! of the MS


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(C) Type periodic registration:

eriodic re!istration is a type of location updatin! procedure that is used to a#oidunnecessary pa!in! of the mo"ile in cases where the MSC ne#er recei#es the IMSI detachmessa!e and also to pre#ent dama!e in case of data"ase failure

Figure A04.((: Location Updating, type periodic regi"tration.

1. The MS is informed #ia the system information if periodic re!istration is used in the cell. Ifperiodic re!istration is used, the MS is told how often it must re!ister. The time is set "y acounter where the #alues are 3 to 2 deci4hours /a unit of si5 minutes0. If the parameteris set to 6ero means periodic re!istration is not used, if the parameter is set to twenty fore5ample, then MS must re!ister e#ery two hours

2. The procedure is controlled "y a timer "oth in the MS and in MSC

'a. when the timer in the MS e5pires, the MS performs a location updatin!, type periodicre!istration and the timers in MS and MSC restart

'". In the MSC there is a time scannin! function for the MS, if the MS does not re!ister withinthe determined inter#al plus a !uard time, then the scannin! function in MSC detects this andthe MS is fla!!ed as detached

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Figure 104.! Location Updating,type periodic registration.


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*. %a !etup:

Call set up can "e classified into two ma7or cate!ories, they are /i0 Call 8rom MS /Mo"ile9ri!inated call0 /ii0 Call to MS /Mo"ile Terminated call0

/i0 Call 8rom MS /Mo"ile 9ri!inated Call0

Mo"ile 9ri!inated call is possi"le when the MS is attached with the MSC)*L+ and islistenin! to the system information.

Figure A04.(*: Mo+ie Originating ca e"ta+i")ment.

1. The MS reuests a S%CC& usin! +AC&

2. The MS indicates that it wants to set up a call. The identity of the MS, IMSI isanaly6ed and the MS is mared as "usy in the *L+

'. Authentication is performed

(. Cipherin! may "e initiated.

. The MSC recei#es a setup messa!e from the MS. This includes the ind of ser#icethe MS wants and the $4num"er. MSC #erify that the MS doesn:t ha#e ser#ices lie"arrin! of out!oin! calls. If the MS is not "arred, the setup of call proceeds.

-. $etween the MSC and the $SC a lin is esta"lished and a CM time slot is sei6ed.The MSC sends a reuest to the $SC to assi!n a TC&. The $SC assi!ns a TC& tothe call /if there is an idle TC& a#aila"le0 and tells the $TS to acti#ate the channel.The $TS sends an acnowled!ement when the acti#ation is completed and the $SC

orders the MS to switch o#er to the TC&. The $SC informs the MSC when theassi!nment is complete.

. An alert messa!e is sent to the MS indicatin! that a rin!in! tone has "een !eneratedon the other side. The rin!in! tone !enerated in the e5chan!e on the $4 su"scri"erside is sent t the MS #ia the !roup switch in the MSC.

;. When the $ su"scri"er answers, the networ sends a connect messa!e to the MSindicatin! that the call is accepted . The MS returns a connect acnowled!ementwhich completes the call set4up.


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/ii0 Call to MS /Mo"ile Terminated Call0

Figure A04.(: %a to M! -rom !'/.

1. The num"er dialed "y the callin! party is called the Mo"ile station IS%< num"er/MSIS%


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i1 Intra $!% 2ando3er:

Figure A04.(4: Intra $!% )ando3er o- a ca.

1. ?#ery (;3ms /two times per second0, the MS sends a measurementreport to the $TS with measurements from the ser#in! cell and the "estnei!h"orin! cells.

2. The $TS adds its own measurements made on the TC&, uplin andforwards the report to the $SC. In the $SC the locatin! function determines if it isnecessary to hando#er the call to another cell "ecause of poor uality or lowsi!nal stren!th in the ser#in! cell.

3. If the $SC decides that a hando#er is reuired it orders the $TS in thenew cell to acti#ate a TC&

4. 9ne new TC& is "ein! allocated and when the new TC& isacnowled!ed, the $SC sends messa!e to the MS #ia the old $TS with theinformation a"out the freuency, time slot and output power to chan!e to.

5. The MS tunes to the new freuency and sends &ando#er access /&90"ursts on the appropriate timeslot. i.e. 8ACC&

6. When the $TS detects the &9 access "ursts it sends physicalinformation containin! the timin! ad#ance o the MS on the 8ACC&. The $TSalso informs the $SC "y sendin! a &9 detection messa!e

7. The MS sends a &ando#er complete messa!e.

. The old $TS is ordered to deacti#ate the old TC& and its associatedsi!nalin! channel /SACC&0

%urin! this intra $SC hando#er, the $SC handles e#erythin! without any in#ol#ementfrom the MSC. &owe#er to eep trac of statistics, the $SC informs the MSC when a

hando#er is performed.


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ii1 Inter $!% 2ando3er:

%urin! the hand o#er, if the nei!h"orin! cell which is !oin! to accept the call, "elon!sto another $SC, then inter $SC hando#er taes place.

Figure A04.(: Inter $!% )ando3er o- a ca.

1. The ser#in! $SC sends a &ando#er reuired messa!e to the MSCto!ether with the identity of the new cell.

2. The MSC nows which $SC controls this $TS and sends a &ando#er+euest to the new $SC.

'. The $SC orders the $TS to acti#ate a TC&, i f there is an idle onea#aila"le.

(. When the new $TS acti#ates the TC&, the $SC sends information a"outthe output power, TS, freuency and hando#er reference to the MSC.

. The MSC passes this information to the old $SC.

-. The MS is told to chan!e to the new TC& and also !ets the hando#erreference in a &ando#er Command messa!e.

. The MS tunes to the new freuency and sends &9 "ursts, containin! thehando#er reference, on the 8ACC&

;. When the new $TS detects the &9 access "urst it sends physical

information containin! timin! ad#ance to the MS on the 8ACC&.>. The new $TS also informs the new $SC "y sendin! a &9 detectionmessa!e. The new $SC in turn informs the MSC. The new path throu!h the!roup switch in the MSC is setup.

13. When the MS recei#es the physical info. it sends a &9 completemessa!e.

11. The new $SC passes the &9 complete info. to the old $SC, #ia the MSC

12. The old TC& and SACC& are deacti#ated "y the $TS


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iii1 Inter M!% 2ando3er:

%urin! the &ando#er, if the new cell "elon!s to another MSC, it is calledInter MSC &ando#er.

Figure A04.(5: Inter M!% )ando3er o- a ca.

1. The ser#in! $SC sends &9 reuired to the MSC.

2. The old MSC ass the new MSC for help.

'. The new MSC allocates a hando#er num"er in order to reroute the call. A &9reuest is sent to the new $SC.

(. The new $SC, in cases where there is an idle TC& in the tar!et cell, tells thenew $TS to acti#ate a TC&.

. The new MSC recei#es the information a"out the new TC& and &9reference.

-. The TC& description and &ando#er reference is passed on to the old MSCto!ether with the &9 num"er.

. A lin is setup "etween the old and new MSC.

;. A &9 command messa!e is sent to the MS with info. a"out which freuencyand timeslot to use in new cell and what &9 reference to use in &9 access "urst

>a. The MS tunes to the new freuency and sends &9 access "ursts on the

8ACC&.

>". When the new $TS detects the &9 access "urst it sends physical info. containin!TA to the MS on the 8ACC&.

13. The old MSC is informed a"out the detection of &9 "ursts.

11. A &9 complete messa!e is sent from the MS. The new $SC and MSC inform theold MSC. The old MSC is informed to the old $SC and the old TC& is released.


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. !)ort Me""age !er3ice:

Figure A04.(6: Mo+ie Originated !)ort Me""age 'ran"-er.

1. The MS sends ser#ice reuest messa!e to the MSC)*L+, with theser#ice type information element indicatin! SMS. The MSC)*L+ may performauthentication and initiate cipherin!

2. A protocol called Control rotocol /C0 messa!e carries the shortmessa!e from the MS to the MSC)*L+. A C acnowled!e messa!e is returnedto MS

'. In the *L+, a chec is performed to see whether the su"scri"er has anSMS su"scription and also it checs other authentication. When the MS haspassed all the checs, the short messa!e is transferred to SMS4IWMSC

(. The short Messa!e is transferred to the SC.

.- A deli#ery or failure report is sent "ac to ser#in! MSC)*L+ #ia SMS4IWMSCdependin! on whether the deli#ery of short messa!e is successful or not.

. A C data messa!e carries the positi#e or ne!ati#e acnowled!ement"ac to MS and finally a C acnowled!ement messa!e is returned to theMSC)*L+

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Figure no. 104.13 Mo"ile originated s#ort message trans$er


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i1 Mo+ie 'erminated !M!:

Figure A04.(: !ucce""-u mo+ie terminated ")ort me""age tran"-er.

1. A short messa!e to a MS is always routed from the SC to the SMS4=MSC.

2. The SMS4=MSC reuests routin! info. from the &L+ "y means of themassa!e send routin! info. for SMS. The messa!e mainly contains the MSIS%

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