In in Mobile_camel

IN in Mobile Services

Manish Das

26-05-2005 BRBRAITT Manish Das

What is the Intelligent Network (IN)?

• ‘Intelligence’ of an ‘Intelligent Network’ lies in its capability of providing personalized services to the users.

• This has been achieved by separating service logic and service data from the switch to which the end user belongs.

• Introduce value added services over a large network at much reduced cost, complexity and time on top of existing infrastructure.

From

Call Processing Logic

• Call processing software and service related software in each SPC Switch.

• Software interacts to complete calls and invoke services.

ServiceLogic

SCP

Service Logic

SSPSS7

Call Processing Logic

• Call processing software in Service Switching Point (SSP).

• Service Logic in SCP.• SSP dialogs with SCP to determine

how to process call.

To


Basic components of IN

SCP - Service Control PointSMF - Service Management FunctionSCE - Service Creation EnvironmentIP - Intelligent Peripheral SSP - Service Switching PointCCSN - Common Channel Signaling

NetworkSTP - Signal Transfer Point

IP

SCE

SSP

SSPSSP

SCP

STP STP

CCSN

SMF

STP

SSPSSP

SSP

LEC/CLEC Network


A GSM Network


Requirements of Mobile Networks

• Real time charging of Voice, SMS and Data calls.

• Providing operator specific services seamlessly even when roaming in other networks.

• Charging real time for all services while roaming.

So, CAMEL aims to provide services irrespective of user’s location Transparent to subscriber

CAMEL-based services“Switch”-based services“HLR”-based services

Seamless servicesHomeRoaming


IN in Mobile Network

• Mobile networks are Intelligent Network structured networks, they have centralized databases (in GSM HLR, VLR) which correspond to IN SCP. GSM also supplies many of the supplementary services that

can be supported on fixed networks by IN solutions.

• IN in Mobile networks is a subset of Landline IN, but customized to meet the special requirements of Mobile services, hence named Customized Application for Mobile Enhanced Logic (CAMEL).

• Mobile services has some unique features like handover, location update, roaming etc.


Components in IN


Some useful concepts

• Points in call (PIC)The points during the call when the IN service logic is allowed to interact with the basic call processings are identified as Points in Call (PICs). So PICs are the activities in MSC/VLR associated with call processing like, Collection of digits, routing, alerting etc. PICs are vendor independent, providing a standardized view of call processing behaviour.

• Detection Points (DP)The points in call processing or during a call, where transfer of control IN service logic or notification of service logic take place. DPs are placed between PICs. DPs can be of two types-Notification (DP-N) and Response (DP-R).

DPPIC

PIC


IN Triggers

• Call termination triggers– Called party busy– No answer

• Call origination triggers– Calling party– Dialed number

• Trigger categories– Subscribed (individual subscriber-based)– Office/group


OSI Reference model and Signaling in CAMEL

Physical

Data link

Network

Transport

Session

Presentation

Application

MTP Level 1

MTP Level 2

MTP Level 3

SCCP

ISUPCAP

TCAP

NULL

OSI-RM SS7

NetworkPart

User / ApplicationParts


CAMEL Subscription Information

• Originating CAMEL Subscription Information (O-CSI): The O-CSI identifies the subscriber as having originating CAMEL services.

• Terminating CAMEL Subscription Information (T-CSI): The T-CSI identifies the subscriber as having terminating CAMEL services.

• Supplementary Service Notification CAMEL Subscription Information (SS-CSI): The SS-CSI identifies the subscriber as having supplementary service invocation notification CAMEL services.

• USSD CAMEL Subscription Information (U-CSI) : The U-CSI identifies a set of subscriber specific mappings from a USSD service code to a gsmSCF address.

• USSD General CAMEL Service Information (UG-CSI) : The UG-CSI globally identifies a set of mappings from a USSD service code to a gsmSCF address. The global mapping applies to all HPLMN subscribers. If, for a particular service code, both U-CSI and UG-CSI are applicable then the U-CSI shall take precedence.


CAMEL Subscription Information

• SMS-CSI: SMS-CSI contains subscription information for subscribers that require CAMEL support of MO SMS. SMS-CSI is transferred to the VLR or to the SGSN on Location Update and Restore Data or when SMS-CSI has changed.

• GPRS-CSI: When processing GPRS Attach requests for subscribers requiring CAMEL support, the SGSN receives a GPRS-CSI from the HLR, indicating the SGSN to request instructions from the gprsSSF. The SGSN monitors on request the GPRS events and informs the gprsSSF of these events during processing, enabling the gprsSSF to control the execution of the GPRS session or individual PDP contexts in the SGSN.

• M-CSI: The HLR contains Mobility management CAMEL Subscription Information (M-CSI) for those subscribers that require CAMEL control of Mobility Management events. M-CSI is sent to the VLR during the Location Update and Restore Data procedures or when M-CSI is modified in the HLR. The M-CSI is deleted in the VLR with the Delete Subscriber Data procedure.


CAMEL Phases

• CAMEL has been evolving in several phases.

• Finalized in 1997, CAMEL phase I introduced improved capabilities as mobile operators could begin to offer services and features to their customers that could work while roaming.

• Phase I of CAMEL does not offer the ability to interact with the Specialized Resource Function (SRF). The SRF is a functional capability found in Voice Response Units (VRU).

• In CAMEL phase I, a call is simply cutoff in progress when an account balance reaches zero.


CAMEL Phases

• Completed in 1998, CAMEL phase II provided many additional capabilities, but perhaps the most significant is support for SRF which allows interaction with specialized network resources such as the Voice Response Unit (VRU). The VRU is an important network element for certain applications such as IN based mobile prepay service.

• The VRU plays voice prompts during prepay account recharge and announcements such as a low balance warning before or during the cal to alert the subscriber of that condition.

• On-line charging.

• Expansion of the range of DPs.


CAMEL Phases

CAMEL Phase III has been developed to support data services available through GPRS, EDGE and UMTS.

CAMEL Phase III also supports

• Real time charging of SMS-MO while roaming.

• Mobility Management.

• SS notfication.


Basic CAMEL Architecture (Phase I)


Basic CAMEL Architecture (Phase I)


Basic CAMEL Architecture (Phase II)

In the second phase the CAMEL feature supports:

- mobile originated and forwarded calls

- mobile terminating calls;

- any time interrogation;

- suppression of announcements;

- announcements, in band user interaction;

- charging features;

- supplementary service invocation notifications;

- USSD interaction with the gsmSCF.


Basic CAMEL Architecture (Phase II)


CAMEL Services

• Prepaid services• Advice of charge though e-value• Mid-call announcement• VPN• Free Phone • Premium number• Universal access number


CAMEL Services

• The most popular services is Prepaid.

• Prepaid is implemented with some additional components.


Trend in Prepaid subscription


Non-IN Prepaid Technology



1. Customer initiates a call

2. MSC detects that the caller uses prepaid account and sets up a voice channel to service node

3. Service node asks from the prepaid billing platform (PBP) if the call should be allowed

4. If call is allowed, a second voice channel is established from service node trough MSC to the called party

• This method costs one extra voice channel compared to IN prepaid.




MSC/SSFAST/DR - Announcements

HLR

SMSScript

Management

SCPCall Control

SDP- PrePaidRating Engine

Account, Service Classand Tariff Data

IVRRefill

Inquiries

GUIGraphical User

Interface

PPASAdministrative System

Voucher Data & Management

Network

Prepaid system architecture


IN Architecture Elements

Service Switching Point (SSP)

– Major function of the SSP is to detect events during call processing, called triggers, that indicate an IN call event

– After triggering, the SSP suspends call processing and starts a series of transactions with the SCP to determine the handling of the call

– Supervises the length of the call



Service Control Point (SCP)

Contains the IN service logic.

Control of call handling

– Call redirection guidance (Free phone)

– call duration

– Real time charging

– announcement control



Intelligent Peripheral (IP)

– Performs specialized resource functions such as:

– Playing announcements

– Collecting digits

– Speech recognition

– Recording and storing voice messages

– Facsimile services...

– Under the control of service logic of SCP.


SDP – description

SDPService Data Point

It is the actual real-time rating engine, handles account deduction, tariffs and service class

Central node in the PrePaid network


PPAS – description

Hosts all subscriber and voucher administrative functions, such as:• voucher maintenance• refill and inquiries• subscriber provisioning • account lifecycle with expiry dates• service class data


CAMEL Call Processing

• MSC call processing model – Basic call state models (BCSMs)

• Originating call model

• Terminating call model


CAMEL Call Processing (O-BCSM Phase I)



DescriptionCAMEL Detection Point

A disconnect indication is received from the originating or the

terminating party. Either calling or called party disconnection is

informed to the gsmSCF.

DP9 O_Disconnect

Indication that the call is accepted and answered by the terminating

party.

DP7 O_Answer

Indication that the O-CSI is active and analysed. The dialled number is received, but not analysed.

DP2 Collected_Info



Data sent to SCP after InitialDP detection:- Event met;

- IMSI;

- Calling Party’s Number;

- Calling Party’s Category;

- Service Key;

- Location information of the calling subscriber;

- ISDN Bearer Capability;

- High Layer Compatibility;

- Basic Service Code;

- Called Party BCD Number. - Call identification information;

- Time and Time Zone information




MSC Call Processing (T-BCSM Phase I)


MSC Call Processing (T-BCSM Phase I)

A disconnect indication is received from the terminating or the originating party.

DP17 T_Disconnect

Call is accepted and answered by terminating party.

DP15 T_Answer

Indication that the T-CSI is active and analysed.

DP12 Term._Attempt_Authorized



CAMEL Call Processing (O-BCSM Phase II)


CAMEL Call Processing (O-BCSM Phase II)

Not reachable event can be determined upon a cause IE

in the ISUP release message.

DP 50 O_Not_Reachable

Indication that a disconnect indication is received from

the originating party during the call establishment

Procedure

DP 10 O_Abandon

A disconnect indication is received from the originating or the

terminating party. Either calling or called party disconnection is informed to the gsmSCF.

DP9 O_Disconnect

Indication that the call is accepted and answered by the terminating

party.

DP7 O_Answer

Indication that an application timer associated with the O_No_AnswerDP expires

DP6 O_No_Answer


Indication that a busy indication is received from the

terminating party

DP 5 O_Busy

Indication that the call establishment failedDP 4 Route_Select_Failure

Indication that the O-CSI is active and analysed. The dialled number is received, but not analysed.

DP2 Collected_Info


CAMEL Call Processing - MOC


CAMEL Call Processing - MOC



Examples of Pre-Call announcements could be:

• Maximum allowed duration for the call

• Low account balance warning, if applicable

• Funds expiration warning, if applicable


MSC Call Processing (T-BCSM Phase II)


CAMEL Call Processing (T-BCSM Phase II)

Not reachable or call establishment failure event can be

determined from the HLR or upon a cause IE in the ISUP

release message.

DP 51 T_Not_Reachable

A disconnect indication is received from the originating

party during the call establishment procedure

DP 18 T_Abandon

A disconnect indication is received from the terminating or the

originating party.

DP17 T_Disconnect

Call is accepted and answered by terminating party.DP15 T_Answer


Indication that an application timer associated with the

T_No_Answer DP expires

DP 14 T_No_Answer

Indication that a busy indication is received from the

destination exchange

DP 13 T_Busy

Term._Attempt_Authorized Indication that the T-CSI is active and analysed.

DP12


CAMEL Call Processing (T-BCSM Phase II)


CAMEL Call Processing - MTC


CAMEL Call Processing –disconnection upon fund expiry


CAMEL Call Processing - MTC


SMS MO


SMS MO


SMS MO using GPRS


SMS MO State Model


SMS MO State Model


GPRS through CAMEL Phase III


SGSN - Successful GPRS Data Transfer- User Disconnects


SGSN - Successful GPRS Data Transfer - Funds Expiry


Real time charging

With CAMEL phase 1 no real time charging was possible.

With CAMEL phase 2 when a call is successfully established, the SCP instructs the underlying network to allow the call for agiven time and to contact the SCP/CSE for further instructions or to release the call immediately after the given time.

But real time charging of SMS-MO while roaming is possible in CAMEL phase 3 only.


Typical Prepaid Implementation


Prepaid account replenishment options

Replenishment of an account can be undertaken in a variety of ways:

• Through the application of a phone card (voucher) through the IP, IVR or USSD

• Through a credit card or ATM transaction

• Through a web interface with a credit card

• Through the system GUI by a Calling Center representative


CAMEL Abbreviations

• BCSM Basic Call State Model• DP Detection Point• EDP Event Detection Point• GMSC Gateway MSC• gsmSCF GSM Service Control Function• gsmSSF GSM Service Switching Function• HPLMN Home PLMN• IPLMN Interrogating PLMN• O-CSI Originating CAMEL Subscription Information• OSS Operator Specific Service• SLPI Service Logic Program Instance• TDP Trigger Detection Point• VPLMN Visited PLMN


THANK YOU

Documents

In in Mobile_camel