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The mobile user dials & presses the SEND button! Now what happens, explain the call flow?
cdmaguru 02-June-2008 09:52:37 AM

Comments


www.mobilitysite.com/.../229808-anyone-else-disapointed-tilt-tytan-ii.html -
Posted by saqlain231


Name some EGPRS KPIs?
Posted by saqlain231


i think 1.)The subscriber pressing the send key initiates a Channel Request message from
the MS to the BSS. This is followed by the assignment of a dedicated control channel
by the BSS and the establishment of the signalling link between the MS and BSS
(SABM-Set Asynchronous Balanced Mode).

2.)The message Request for Service is passed to the MSC which relays it to the VLR.
The VLR will carry out the authentication process if the MS has been previously
registered on this VLR - if not, the VLR will have to obtain authentication parameters
from HLR. The diagram assumes the MS was previously registered on this VLR.

3.)Subscriber authentication (optional) takes place using authentication messages and
encryption algorithms and, if successful the C all setup can continue. If ciphering is to
be used this is initiated at this time as the setup message contains sensitive
information.

4.)The message "Set Up" is sent by the MS to the MSC accompanied by the call
information (type of call, and number being called etc.). The message is forwarded
from the MSC to the VLR.

5.)The MSC may initiate the MS IMEI check (is the MS stolen? etc). Note that this check
may occur later in the message sequence.

6.)In response to the message ``Set Up" (sent at step 4), the VLR sends the message
"Complete Call" to the MSC , which notifies the MS with "Call Proceeding".

7.)The MSC then assigns a traffic channel to the BS S ("Assignment Command"), which
in turn assigns an air interface traffic channel. The MS responds to the BS S (which
responds in turn to the MSC ) with "Assignment Complete".

8.)An "Initial and Final Address Message (IFAM)" is sent to the PSTN. Ring tone is applied
at the MS in response to ``Alerting", which the MSC sends to the MS when the PSTN
responds with an ``Address C omplete Message (ACM)".

9.)When answered ("Answer (ANS)" from the PSTN), the message "Connect" is
forwarded to the MS by the MSC , stopping the MS ring tone. The MSC then connects
the GSM traffic channel to the PSTN circuit, thus completing the end to end traffic
connection.

10.) Conversation takes place for the duration of the call.

Posted by waqasahmad


MOBILE TO LAND SEQUENCE:

1.)The subscriber pressing the send key initiates a Channel Request message from
the MS to the BSS. This is followed by the assignment of a dedicated control channel
by the BSS and the establishment of the signalling link between the MS and BSS
(SABM-Set Asynchronous Balanced Mode).

2.)The message Request for Service is passed to the MSC which relays it to the VLR.
The VLR will carry out the authentication process if the MS has been previously
registered on this VLR - if not, the VLR will have to obtain authentication parameters
from HLR. The diagram assumes the MS was previously registered on this VLR.

3.)Subscriber authentication (optional) takes place using authentication messages and
encryption algorithms and, if successful the C all setup can continue. If ciphering is to
be used this is initiated at this time as the setup message contains sensitive
information.

4.)The message "Set Up" is sent by the MS to the MSC accompanied by the call
information (type of call, and number being called etc.). The message is forwarded
from the MSC to the VLR.

5.)The MSC may initiate the MS IMEI check (is the MS stolen? etc). Note that this check
may occur later in the message sequence.

6.)In response to the message ``Set Up" (sent at step 4), the VLR sends the message
"Complete Call" to the MSC , which notifies the MS with "Call Proceeding".

7.)The MSC then assigns a traffic channel to the BS S ("Assignment Command"), which
in turn assigns an air interface traffic channel. The MS responds to the BS S (which
responds in turn to the MSC ) with "Assignment Complete".

8.)An "Initial and Final Address Message (IFAM)" is sent to the PSTN. Ring tone is applied
at the MS in response to ``Alerting", which the MSC sends to the MS when the PSTN
responds with an ``Address C omplete Message (ACM)".

9.)When answered ("Answer (ANS)" from the PSTN), the message "Connect" is
forwarded to the MS by the MSC , stopping the MS ring tone. The MSC then connects
the GSM traffic channel to the PSTN circuit, thus completing the end to end traffic
connection.
Posted by jahangir1983


MOBILE TO LAND SEQUENCE:

1.)The subscriber pressing the send key initiates a Channel Request message from
the MS to the BSS. This is followed by the assignment of a dedicated control channel
by the BSS and the establishment of the signalling link between the MS and BSS
(SABM-Set Asynchronous Balanced Mode).

2.)The message Request for Service is passed to the MSC which relays it to the VLR.
The VLR will carry out the authentication process if the MS has been previously
registered on this VLR - if not, the VLR will have to obtain authentication parameters
from HLR. The diagram assumes the MS was previously registered on this VLR.

3.)Subscriber authentication (optional) takes place using authentication messages and
encryption algorithms and, if successful the C all setup can continue. If ciphering is to
be used this is initiated at this time as the setup message contains sensitive
information.

4.)The message "Set Up" is sent by the MS to the MSC accompanied by the call
information (type of call, and number being called etc.). The message is forwarded
from the MSC to the VLR.

5.)The MSC may initiate the MS IMEI check (is the MS stolen? etc). Note that this check
may occur later in the message sequence.

6.)In response to the message ``Set Up" (sent at step 4), the VLR sends the message
"Complete Call" to the MSC , which notifies the MS with "Call Proceeding".

7.)The MSC then assigns a traffic channel to the BS S ("Assignment Command"), which
in turn assigns an air interface traffic channel. The MS responds to the BS S (which
responds in turn to the MSC ) with "Assignment Complete".

8.)An "Initial and Final Address Message (IFAM)" is sent to the PSTN. Ring tone is applied
at the MS in response to ``Alerting", which the MSC sends to the MS when the PSTN
responds with an ``Address C omplete Message (ACM)".

9.)When answered ("Answer (ANS)" from the PSTN), the message "Connect" is
forwarded to the MS by the MSC , stopping the MS ring tone. The MSC then connects
the GSM traffic channel to the PSTN circuit, thus completing the end to end traffic
connection.
Posted by jahangir1983


MOBILE TO LAND SEQUENCE:

1.)The subscriber pressing the send key initiates a Channel Request message from
the MS to the BSS. This is followed by the assignment of a dedicated control channel
by the BSS and the establishment of the signalling link between the MS and BSS
(SABM-Set Asynchronous Balanced Mode).

2.)The message Request for Service is passed to the MSC which relays it to the VLR.
The VLR will carry out the authentication process if the MS has been previously
registered on this VLR - if not, the VLR will have to obtain authentication parameters
from HLR. The diagram assumes the MS was previously registered on this VLR.

3.)Subscriber authentication (optional) takes place using authentication messages and
encryption algorithms and, if successful the C all setup can continue. If ciphering is to
be used this is initiated at this time as the setup message contains sensitive
information.

4.)The message "Set Up" is sent by the MS to the MSC accompanied by the call
information (type of call, and number being called etc.). The message is forwarded
from the MSC to the VLR.

5.)The MSC may initiate the MS IMEI check (is the MS stolen? etc). Note that this check
may occur later in the message sequence.

6.)In response to the message ``Set Up" (sent at step 4), the VLR sends the message
"Complete Call" to the MSC , which notifies the MS with "Call Proceeding".

7.)The MSC then assigns a traffic channel to the BS S ("Assignment Command"), which
in turn assigns an air interface traffic channel. The MS responds to the BS S (which
responds in turn to the MSC ) with "Assignment Complete".

8.)An "Initial and Final Address Message (IFAM)" is sent to the PSTN. Ring tone is applied
at the MS in response to ``Alerting", which the MSC sends to the MS when the PSTN
responds with an ``Address C omplete Message (ACM)".

9.)When answered ("Answer (ANS)" from the PSTN), the message "Connect" is
forwarded to the MS by the MSC , stopping the MS ring tone. The MSC then connects
the GSM traffic channel to the PSTN circuit, thus completing the end to end traffic
connection.
Posted by jahangir1983



Posted by waqqas1


This causing to transmit an Origination Message on the access channel. Now from MS -> BS
here is the message flow

ACH: Origination Message
ACK_SEQ: 7 (acknowledgment sequence number = mod 8)
MSG_SEQ: 6 (message sequence number)
ACK_REQ: 1 (ack required)
VALID_ACK: 0 (this message is not acknowledgment to previous msg)
ACK_TYPE: 0
I MSI: 321-456-789
AUTH_MODE: 0 (no authentication fields)
SLOTTED_MODE: 1
Service option: (6) Voice (13k)
PM: 0 (voice privacy not supported)
Thari: 87845437248


Step 2 MS <- BS
The BS acknowledges receiving the origination by sending a BS Acknowledgement on the paging
channel.
PGCH :ORDER Message
ACK_SEQ: 6
MSG_SEQ: 0
ACK_REQ: 0
VALID_ACK: 1 (message is a acknowledgment to a previous message)
ORDER: Base Station Acknowledgement Order
Step 3 MS <- BS
The system arranges the resources for the call and starts transmitting (NULL frames) on the traffic
channel. The BS notifies the mobile in a Channel Assignment Message on the paging channel
and the MS goes to a traffic channel.
PGCH: Channel Assignment Message
ACK_SEQ: 6
MSG_SEQ: 1
ACK_REQ: 0
VALID_ACK: 0
I MSI: 972-849-5073
ASSIGN_MODE: Traffic Channel Assignment
GRANTED_MODE: 2
CODE_CHAN: 12
ENCRYPT_MODE: Encryption disabled ( since authentication was not performed hence no
encryption)
BAND_CLASS: PCS band
CDMA_FREQ: 425
Step 5
The mobile on receiving atleast 2 NULL frames concludes that it is on the right TCH. The MS and BS acknowledgment each other's traffic channel acknowledgment messages. Now the mobile is on Traffic Channel.

Step 6
MS <- BS
PGCH: Order Message
ACK_SEQ: 7
MSG_SEQ: 0
ACK_REQ: 1
ENCRYPTION: 0 (no encryption of type-specific fields)
ORDER: Base Station Acknowledgement Order
Step 7 MS -> BS
ACH: Order Message
ACK_SEQ: 0
MSG_SEQ: 0
ACK_REQ: 0
ENCRYPTION: 0
ORDER: Mobile Station Acknowledgement Order
Step 8 MS <- BS
The base station and the mobile negotiate the type of call .In this case voice ( 13K). Service
Negotiation takes place.
FTCH: Service Connect Message
ACK_SEQ: 7
MSG_SEQ: 1
ACK_REQ: 1
ENCRYPTION: 0
Forward Traffic Channel Rate (Set 2): 14400, 7200, 3600, 1800
Reverse Traffic Channel Rate (Set 2): 14400, 7200, 3600, 1800
Service option: (6) Voice
Forward Traffic Channel: Primary Traffic
Reverse Traffic Channel: Primary Traffic
MS -> BS
RTCH: Service Connect Completion
ACK_SEQ: 1
MSG_SEQ: 0
ACK_REQ: 1
ENCRYPTION: 0
MS <- BS
FTCH: Order Message
ACK_SEQ: 0
MSG_SEQ: 0
ACK_REQ: 0
ENCRYPTION: 0
ORDER: Base Station Acknowledgement Order
The audio circuit is completed and the mobile caller hears ringing

Step 7
The base station and the mobile negotiate the type of call eg. 13k voice, etc. Service Negotiation take place.
BS -> MS
FTCH: Service Connect Message
ACK_SEQ: 7
MSG_SEQ: 1
ACK_REQ: 1
ENCRYPTION: 0
Forward Traffic Channel Rate (Set 2): 14400, 7200, 3600, 1800
Reverse Traffic Channel Rate (Set 2): 14400, 7200, 3600, 1800
Service option: (6) Voice
Forward Traffic Channel: Primary Traffic
Reverse Traffic Channel: Primary Traffic
BS <- MS
RTCH: Service Connect Completion
ACK_SEQ: 1
MSG_SEQ: 0
ACK_REQ: 1,
ENCRYPTION: 0
Step 8
BS -> MS
The mobile is made to ring to present the user an Incoming call display using the Alert With
Information Message.
FTCH: Alert With Information
ACK_SEQ: 3 MSG_SEQ: 1 ACK_REQ: 1 ENCRYPTION: 0
SIGNAL_TYPE = Alerting
ALERT_PITCH = Standard
SIGNAL = Long
RECORD_TYPE = Calling Party Number
NUMBER_TYPE = National Number
NUMBER_PLAN = Telephony Numbering Plan
PI = Presentation Allowed
SI = Network Provided
CHARi = 9845437248
BS < -MS
Acknowledging the previous message.
RTCH: Order
ACK_SEQ: 1 MSG_SEQ: 4 ACK_REQ: 0
ENCRYPTION: 0
ORDER: Mobile Station Acknowledgement Order
Posted by meenakshi123


MOBILE TO LAND SEQUENCE:

1.)The subscriber pressing the send key initiates a Channel Request message from
the MS to the BSS. This is followed by the assignment of a dedicated control channel
by the BSS and the establishment of the signalling link between the MS and BSS
(SABM-Set Asynchronous Balanced Mode).

2.)The message Request for Service is passed to the MSC which relays it to the VLR.
The VLR will carry out the authentication process if the MS has been previously
registered on this VLR - if not, the VLR will have to obtain authentication parameters
from HLR. The diagram assumes the MS was previously registered on this VLR.

3.)Subscriber authentication (optional) takes place using authentication messages and
encryption algorithms and, if successful the C all setup can continue. If ciphering is to
be used this is initiated at this time as the setup message contains sensitive
information.

4.)The message "Set Up" is sent by the MS to the MSC accompanied by the call
information (type of call, and number being called etc.). The message is forwarded
from the MSC to the VLR.

5.)The MSC may initiate the MS IMEI check (is the MS stolen? etc). Note that this check
may occur later in the message sequence.

6.)In response to the message ``Set Up" (sent at step 4), the VLR sends the message
"Complete Call" to the MSC , which notifies the MS with "Call Proceeding".

7.)The MSC then assigns a traffic channel to the BS S ("Assignment Command"), which
in turn assigns an air interface traffic channel. The MS responds to the BS S (which
responds in turn to the MSC ) with "Assignment Complete".

8.)An "Initial and Final Address Message (IFAM)" is sent to the PSTN. Ring tone is applied
at the MS in response to ``Alerting", which the MSC sends to the MS when the PSTN
responds with an ``Address C omplete Message (ACM)".

9.)When answered ("Answer (ANS)" from the PSTN), the message "Connect" is
forwarded to the MS by the MSC , stopping the MS ring tone. The MSC then connects
the GSM traffic channel to the PSTN circuit, thus completing the end to end traffic
connection.

10.) Conversation takes place for the duration of the call.
Posted by sagitraz

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