Call Management

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CALL & MOBILITY MANAGEMENT

Connection Management
What is Connection Management ? Connection Management enables different CM sub-layer entities to communicate with their pier entity using different MM connections. Different CM sub-layer entities use different MM connections. Different MM connections are identified by Protocol Discriminator PD and, additionally by Transaction Identifier TI.

Mobile To Land Call Set-up Scenario Phases of Mobile To Land Call ( Mobile Originated Call- MO Call )

• SETUP PHASE • RINGING PHASE • CONVERSATION PHASE • RELEASE PHASE

Mobile To Land Call Set-up Scenario

• SETUP PHASE
- REQUEST FOR SERVICE ( CHANNEL ) BY MS - CM SERVICE REQUEST - AUTHENTICATION - CIPHERING - EQUIPMENT VALIDATION ( EIR CHECK ) - SETUP MESSAGE - VALIDATION AT VLR - ASSIGNMENT

MOBILE TO LAND CALL - I Request For Service
MS BSS MSC/ VLR

1

Channel Request

RACH
2

SDCCH Assignment

AGCH
3

CM Service Request

SDCCH
4

CM Service Accept

Mobile To Land Call Set-up Scenario • CM SERVICE REQUEST - The Call Control (CC) entity of MS initiates the establishment of CC connection by requesting MM sub-layer of the mobile to establish MM sub-layer connection. - Upon establishment of MM connection CM SERVICE ACCEPT message is received from n/w. • SETUP MESSAGE - CC entity sends a setup message to its peer entity.

MOBILE TO LAND CALL - II Call Setup
MS BSS MSC/ VLR

5

Call Setup Request

SDCCH
Call Proceeding
6

SDCCH Assign Trunk and radio
7

Assign TCH

SDCCH Radio Assignment Complete SDCCH Trunk and Radio Assignment Complete

Mobile To Land Call Set-up Scenario Call Setup message
MSC/VLR Release Complete message to MS No

Is the requested basic service provisioned for the subscriber ? Yes

Release Complete message to MS Yes

Preliminary Digit Analysis
Is the number of digits less than the minimum expected? No 1. Check of ODB( BAOC/BOIC/ BOIC Ex HC )

2. Subscriber call barring checks ( BAOC/BOIC e ASSIGNM ENT

Mobile To Land Call Set-up Scenario • ASSIGNMENT - A BSSMAP message ‘Assignment Command ’ is sent by MSC to BSS. - The message contains a free CIC on A-Interface for terrestrial channel allocated by MSC. - A free TCH is allocated by the BSS and MS is informed to attach to this TCH. - On receiving a response from BSS MSC switches the speech path towards the calling MS.

Note : Mobile has not connected user connection as yet.

MOBILE TO LAND CALL - III Call Setup
MS BSS MSC/ VLR HLR GMSC PSTN

Network Setup ( Dialed Digits )
8

Network Alerting
9

Alerting

FACCH
10

Connect

Connect

Start Billing

FACCH
11

Connect Acknowledge

FACCH

MOBILE TO LAND CALL - IV Call Release
MS BSS
Disconnect Network Release

MSC/ VLR

HLR

GMSC

PSTN

12

13

Release

FACCH
14

Release Complete

FACCH
Clear Command
15

Channel Release

FACCH

Release Complete

Land To Mobile Call Set-up Scenario Phases of Land To Mobile Call ( Mobile Terminating - MT Call )

• Routing Analysis • Paging • Authentication • Ciphering • Call-Setup • Call Release

Architecture For Mobile Terminated Call
VISITING PLMN A- Interface IAM ( ISUP ) GMSC- B
AC K( MS
( SRI SD N MSI )

MSC-B BSS-B VLR-B
RN )

Air Interface

PR N

K(

MS

HLR-B

AC

RN )

MS

LAND TO MOBILE CALL - I

Routing Analysis
MSC/VLR HLR GMSC PSTN

1 2

Incoming Call Get Route Get Route

( MSISDN )

3

( MSISDN )

( IMSI )
Routing Information

4

( MSRN )

Routing Information

5

Incoming Call

( MSRN )

( MSRN )

LAND TO MOBILE CALL - II

Paging
MS BSS
Perform Page Page
6 7

MSC

(TMSI)

PCH
Channel Request

( RACH )
8

Access Granted

( AGCH )
Paging Response
9

( TMSI, LAI )

SDCCH

Page Response

LAND TO MOBILE CALL - III Call Set-up
MS BSS
Call Set Up

MSC

10

SDCCH
Call Set Up Confirm

11

SDCCH
Assign Trunk & Radio Channel Assign Radio...
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