CAMEL (Customized Application for the Mobile network Enhanced Logic) is a standard for Intelligent Networks for mobile communications networks.  It is currently deployed in all regions of the world, enabling mobile network operators to offer fast and efficient services to their subscribers.

For operators that consider prepay a must-have, CAMEL (Customized Application for Mobile Enhanced network Logic) is becoming the prime method for putting the intelligence into intelligent networks. 

Initially designed for circuit-switched calls, CAMEL (phases I and II) triggered the intelligent network (IN) during a prepay call, so that companies could swiftly assess and respond to subscribers' status information regarding location, account balances and service characteristics. 

CAMEL phase III adds prepaid support for SMS and data services. By supporting SMS, phase III allows GSM operators to offer real-time charging for Mobile Originated Short Messages (MO-SMS) without the need for proprietary devices. By enabling real-time charging for data services, CAMEL III opens up options for prepay billing, with parameters based on the location of the sender, the destination of the message, as well as date and time. 

Since its initial phases, there has been an inextricable link between the evolution of GSM and its many phases, and those of CAMEL. For carriers evolving from TDMA to GSM, and onto second-generation GSM to 3GPP networks (UMTS), CAMEL Phase III (now a part of the 3GPP GSM spec) will be germane to creating a foundation for service differentiation by enabling roaming. 

IN implementations, and subsequent roaming capabilities in large multi-vendor networks were difficult without CAMEL, because most vendors had developed proprietary IN standards around recommendations from CS1, the legacy standard from ETSI. 

"Roaming is now being demanded by subscribers in Europe, South America and even North America. By giving end users access to operator-specific services when roaming outside their home network, there will be a perception of added value and an opportunity for carriers to charge accordingly and differentiate themselves," says Rogier Noldus, senior specialist, Intelligent Networks, Ericsson. Because CS1 has been open to many interpretations over the years, CAMEL is standardized to a "bit level," so that comments, questions and compatibility issues can be addressed in a standard manner, Noldus contends.

Where multiple interpretations of previous standards inhibited intelligent networks, CAMEL will open the doors to inter-vendor compatibility. Ericsson, Nokia, Alcatel and Siemens work together regularly to improve CAMEL. "We work like friends, rather than competitors in the 3GPP environment, which has become a great breeding ground for building standards," says Noldus, claiming

that engineers working on CAMEL want to ensure the industry gets the most out of GSM as a whole." 

For carriers, CAMEL enables carriers to take inbound roaming subscribers into their networks. 

"Any time operators can increase traffic on their networks, as well as the throughput and usage on those networks, it is an attractive proposition," says Noldus, noting that once carriers get roaming partners, subscribers can camp on MSCs (mobile switching centers) in their respective territories, and open up roaming to prepay customers. Noldus adds that European operators deploying CAMEL for inbound roaming subscribers are reporting increases in network usage. 

CAMEL-Phase III 

With CAMEL - Phase III - real-time charging moves from circuit switched to wireless with IN capabilities based on GPRS and UMTS. For operator that have implemented prepaid GPRS services, CAMEL phase III provides a standard interface between SMC and SCP within packet-based networks. Now, CAMEL enables the mobile station to request data from the SGSN (a serving GPRS support node) and GGSN (Gateway GPRS Support Node) so that the IN is involved during the data context creation. The SGSN triggers the SCP, which checks the user's account as in the circuit switched case. The SGSN updates the SCP in regular intervals with status information (time, volume, position) about the PDP context. The SCP performs hot-rating, decrements the account, and requests the SGSN to continue processing or to release the PDP context. Depending on the number, the duration and the traffic of the GPRS sessions, this can impose important performance requirements on the SGSN and SCP. 

CAMEL Phase IV (also known as "release 5" ) is slated for early 2005, is now being finalized. It is based on IMT-2000, the ITU's framework for global wireless access that links terrestrial and/or satellite networks. 

The Practical Side 

Like any standard, carriers and operators cannot look through rose-tinted glasses: For CAMEL III to really "work," there have to be many operators who implement it, as the whole point is to allow roaming in other places, says Steve Menear, associate VP within the IN division of Comverse. 

Because it is relatively expensive to upgrade switches, many carriers are "sitting on their hands" waiting for others to do it first. "It will be the operators who need support for charging for short messages and GPRS services that will be the first too implement CAMEL III," says Menear. "It was the same with CAMEL II; though it seemed obvious everyone should want it, it was a matter of the biggest

operators in Western Europe to go ahead before others thought the value outweighed the cost." Because CAMEL does not support all data services, the decision to implement CAMEL III or IV will be a business decision. "Whether you spend the money to upgrade switches to support roamers depends on your bu siness plan," adds Menear.

CAMEL

One of the biggest enhancements in GSM phase 2+ is the mobile network integration with intelligent network (IN). Customised Application for Mobile network Enhanced Logic (CAMEL) is a GSM 2+ feature that makes world

wide support of Operator Specific Services (OSS) possible. CAMEL is not a service, but a feature to create services. ETSI SMG1 group has worked since 1994 to create the specifications for CAMEL and its development towards

UMTS Virtual Home Environment (VHE). CAMEL Phase 1 specification was released 1996 and phase 2 in 1997. Current specification level is phase 3 (GSM

09.78) .

CAMEL phase 1 support call screening and supervision services, number translation services, enhanced call forwarding (time and location dependent)

and fraud information gathering services (FIGS) and it is implemented to support both mobile originated and terminated calls. CAMEL phase 1 is limited to basic call services and the trigger points are answer and disconnect, and the

services include optimal routing of the call. Phase 2 supports private numbering plan (SPNP), Prepaid Card Service with Advice of Charge, Free phone and

Universal number. Phase 2 includes more trigger points and usage of several CAMEL Service Environments (CSE), which makes it possible for subscriber to receive message on his own language even when roaming abroad. Phase 3

has additional features that allow roaming subscribers to access their full portfolio of IN services. CAMEL phase 3 connects the home and visited mobile

networks to various Intelligent Network (IN) platforms used throughout national networks to provide features such as pre-paid roaming services, special

numbers (e.g. 123 for voice mail works everywhere) and closed user groups (office extension numbers work everywhere) personal numbering and more

complex location dependent services. As a result, CAMEL is a relatively inexpensive method of allowing telecom operators to add new services to the

existing network infrastructure.

 Value-added Service Characteristics

All VAS share the same characteristics:

1. Not a form of basic service but rather adds value total service offering

2. Stands alone in terms of profitability and/or stimulates incremental demand for core service(s)

3. Can sometimes stand alone operationally4. Does not cannibalize basic service unless clearly favorable5. Can be an add-on to basic service, and as such, may be sold at a

premium price6. May provide operational and/or administrative synergy between or

among other services – not merely for diversification

Every VAS will demonstrate one or more of the above characteristics. Furthermore, a value-added service will never stand in stark contrast to any of the above characteristics.

VAS also have a certain time dimension associated with them. Subjectively speaking, a value-added service today becomes a basic service when it becomes sufficiently common place and widely deployed to no longer provide substantive differentiation on a relative basis.

Relationship to other Services

There are two types of VAS. The first service type are those value-added services that stand alone from an operational perspective. These types of services need not be coupled with other services, but they can be. Many non-voice services fall into this category. They are often provided as an optional service along with voice services, but they could be offered and used by themselves without the voice service. For example, SMS could be offered and used as a service without voice calling.

The second, and arguably more numerous and important type of VAS, are those services that do not stand-alone. Instead, this category adds value to existing services. While it seems implicit in the definition of value-added, this is an important principle that makes value-added services stand apart from other services.

Value-added Services Examples

There are many services that could be considered "value-added". For discussion purposes, we will a few of these services below.

Push-to-Talk

Push-to-Talk (PTT) is a VAS because it:

Drives additional revenue to the wireless carrier, but doe not cannibalize existing revenues

Provides differentiated service offerings May be packaged with various other VAS such as MIM to provide

even greater value

Call Management Services

This type of service can not stand alone as a service. Instead, it adds value to a core service by allowing the subscriber to manage incoming and/or outgoing calls. For example, value-added service interactions occur when the subscriber receives a call. Many call management services allow the subscriber to establish when, where, and under what circumstances they may be reached by calling parties. This provides value to the core service - voice communications - by way of increased control and flexibility.

Depending on the specific commercial situation, this value-added service could be offered as either a premium service (at a premium price) or be bundled with other the core service offering. The benefit of bundling would be to provide a differentiated core service and/or to increase the use of the core service.

Location Sensitive Billing

This is another example of a service that can not stand-alone. Instead, location sensitive billing (LSB) adds value to the core service by location enabling the core service. Location sensitive billing can be used in conjunction with post-paid, prepaid, and/or VPN based mobile communications services to establish zones for which differentiated billing treatment may be applied. For example, a "home zone", "work zone", and "premium price zone" could be established to allow an operator to offer differentiated service to its customers.

This is viewed as a value-added service to both the customer and the mobile operator. The customer benefits from LSB through his ability to use the mobile phone at preferred rates based on location. The wireless carrier benefits from incremental revenues derived from additional usage and from premium charge zones where there is already high demand and perhaps overly taxed system capacity. While the issue of potential cannibalization of existing service arises, customer behavior and studies indicate a net benefit derived from overall increased usage and revenues.

Taken together, call management services and LSB also depict characteristic number six, operational synergy. Call management services add value in terms of providing the user options depending on location. For example, the user may want to receive certain calls at the home zone, but not at work, and perhaps receive only urgent calls when traveling or on vacation. LSB provides the additional synergistic benefit of location based billing when the user is in those various locations.

Mobile Data Services

This is an example of a value-added service that does stand-alone. Mobile data services are considered value-added because they depict many of the characteristics discussed earlier.

Does not cannibalize existing services Can be offered at a premium price Provides differentiation Can provide synergy with basic service

Largely due to the current state of mobile communications evolution, many non-voice services can be considered to be value-added. However, the extent to which additional value-added services can be layered on top of mobile data services will determine the limit of their value. For example, many non-voice services will have even greater value through personalization. Two of the most significant ways to personalize wireless services are through location enabling them and making them personal profile driven.

Mobile data services are utilized to obtain information, content, and to perform transactions. All of these activities are more meaningful if they are tailored to the individual. Location based services add value by

way of putting the data into a location context for the user. Personal profiles further enhance the value through Personalization.

A value-added service (VAS) is popular as a telecommunications industry term for non-core services or, in

short, all services beyond standard voice calls and fax transmissions but, it can be used in any service

industry for the services providers provide for no cost to promote their main service business. In

telecommunication industry on a conceptual level, value-added services add value to the standard service

offering, spurring the subscriber to use their phone more and allowing the operator to drive up their ARPU.

For mobile phones, while technologies like SMS, MMS and GPRS are usually considered value-added

services, a distinction may also be made between standard (peer-to-peer) content and premium-charged

content.

Value-added services are supplied either in-house by the mobile network operator themselves or by a third-

party value-added service provider (VASP), also known as a content provider (CP). VASPs typically

connect to the operator using protocols like Short message peer-to-peer protocol (SMPP), connecting either

directly to the short message service centre (SMSC) or, increasingly, to a messaging gateway that allows

the operator to control and charge of the content better.

CAMEL:INTRO

CAMEL: An IntroductionZahid Ghadialy

Date: 25/07/2004

Introduction

Customised Applications for Mobile network Enhanced Logic also known as CAMEL was developed as a standard for mobile intelligence across different vendor equipments for GSM network. What this means is that the end user should be able to roam between different networks (maybe in different countries) and be reachable at the same number and should receive only one bill from the original service provider (Home Operator).

Before CAMEL, the GSM networks used INAP (Intelligent Network Application Part) for injecting intelligence in GSM networks. The limitations of INAP was that it did not support mobility management. CAMEL solved the mobility management problem and provided with much more functionality. With the evolution of 3G standards, CAMEL has evolved to provide new functionalities that will be discussed later.

 

 

 

 

CAMEL has been divided into Phases. The last section in this primer lists the functionality of each phases. The latest Phase is Phase 4. If an IPLMN (Interrogating PLMN) or VPLMN (Visiting PLMN) supports CAMEL Phase 4, it shall also provide the functionality of all previous CAMEL phases.

The first commercial implementation of CAMEL (phase 1) was in August 2000 by France Telecom Mobiles (France), Mobistar (Belgium) and Dutchtone (The Netherlands).

NOTE: CAMEL feature is a network feature and not a supplementary service. It is a tool to help the network operator 

Applicability of CAMEL procedures

MEL fThe CAeature is applicable to Mobile Originated and Mobile Terminated Call Related Activities. CAMEL procedures are applicable to all circuit switched basic services without distinction (except Emergency calls).

The CAMEL feature is applicable to Supplementary Services Invocation CAMEL procedures are applicable to GPRS sessions and PDP contexts CAMEL procedures are applicable to Mobile Originating/Terminating short

message service through both circuit switched and packet switched serving network entities

CAMEL procedures are applicable to IP multimedia services (except Emergency calls) to support legacy services

CAMEL shall support IPMM sessions which are based on the same charging paradigm as CS/PS calls. This applies most probably to VoIP and Video over IP.

CAMEL procedures are applicable to IP multimedia sessions addressed by either E.164 numbers or SIP URLs.

Example of CAMEL procedure

Before we proceed further and use more technical terms, it would be wise to understand CAMEL procedure with the help of some examples.

Take a simple scenario of a voice call being made. When a subscriber starts to make a call, this request is received by the network's Mobile Switching Centre (MSC). The MSC then sends a message that 'queries' the SCP's database. Note that the essential element of any CAMEL solution is a Service Control Point (SCP). This unit effectively hosts a database which holds the instructions needed for an intelligent application.

The SCP processes that query, comes up with an appropriate response and then sends a message back to the MSC telling what action it should take with the subscriber’s request for a specific service. The call is then connected in the most appropriate manner, a process which is transparent to the customer. A very good example of this process in action is short code dialling over a VPN (Virtual Private Network) where the user calls a colleague’s internal extension telephone number but is, in fact, routed to that person’s mobile phone which is roaming abroad.

The main addition in CAMEL phase 2 which phase 1 omitted is support for a Specialised Resource Function (SRF) a component most often found in Voice Response Units (VRUs). For example, when an account balance reaches zero for a pre-paid customer under phase 1, the customer will simply be cut off. With phase 2 thanks to support for SRF, the customer will hear automatically generated messages from the Voice Response Unit warning that the balance is dangerously low before a call and even during the call. Naturally this leads to greater customer satisfaction. 

Technical Terms

For any further discussions we would need to use some technical terms. They are discussed in this section.

Interrogating PLMN (IPLMN): The PLMN that interrogates the Home PLMN (HPLMN) for information to handle mobile terminating call.

CAMEL Service Environment (CSE): A CSE is a logical entity which processes activities related to Operator Specific Services (OSS).

CAMEL Subscription Information (CSI): Identifies that CAMEL support is

required for the subscriber and the identities of the CSEs to be used for that support.

Service Control Function (SCF): SCF contains the actual independent service logic to apply to the call.

Basic Call State Model (BCSM): BSCM represents an abstract view of call processing, seen from the perspective of service feature control performed by the SCF. The BCSM consists of two sets of call processing logic, Originating BCSM (O-BCSM) and Terminating BCSM (T-BCSM).

Points in Call (PIC): PIC are defined by standards to represent those points in which action might be taken. They provide a view of a state or event in which call processing logic may initiate an action, such as suspension of call processing while a database is queried.

Detection Points (DP): DP represent transitional events that occur between some PICs.

Triggers: A trigger is the term used to define specific call-processing logic associated with a given point in call. Triggers are nothing more than software logic that is loaded in a network element to carry out instructions to initiate an intelligent network process based on analysis of conditions at a detection point.

Events: Unlike a trigger, which depends on some form of input criteria, an event is simply a call occurrence such as no answer, busy signal or call termination.

Arming of detection points: Detection points have two classifications: Trigger Detection Points (TDP) and Event Detection Point (EDP). A detection point is armed if control logic is established to initiate service control based on a trigger or event.

GSM Service Control Function (gsmSCF): functional entity that contains the CAMEL service logic to implement OSS. It interfaces with the gsmSSF, the gsmSRF, the GMLC and the HLR.

GSM Service Switching Function (gsmSSF): functional entity that interfaces the MSC or GMSC to the gsmSCF. The concept of the gsmSSF is derived from the IN SSF, but uses different triggering mechanisms because of the nature of the mobile network.

GSM Specialised Resource Function (gsmSRF): functional entity which provides various specialized resources. It interfaces with the gsmSCF and with the MSC.

Examples of Signalling procedures

[13] gives example of Signalling procedures using CAMEL for originating and terminating calls and has been described below.

Mobile Originating Calls:

If an active originating CAMEL Subscription Information (CSI) is found in the VLR during the call set up of a MS, the Visited Service Switching Function (VSSF) sends an InitialDetectionPoint message to the gsmSCF and the VMSC suspends the call processing. The InitialDetectionPoint shall always contain the service key, called and calling party number, calling party’s category, location number, bearer capability, event type Basic Call State Model (BCSM), location information and the International Mobile Station Identity (IMSI). After the service logic processing CAMEL specific handling is initiated from the gsmSCF, see figure above.

Mobile Terminating Calls:

In the case of mobile terminating call, the Gateway MSC (GMSC) in the interrogating PLMN identifies the HLR of the called party with the help of the MSISDN. Then the GMSC sends a RoutingInformation-Request to the HLR. The HLR checks the CSI of the called party and sends the information stored in the subscriber record back to the GMSC. Now, the GMSC acts according to CSI. If the terminating CSI is active the trigger criteria of a Detection Point (DP) is fulfilled and the call processing is suspended. An InitialDP message, which shall always contain the service key, called party number, event type BCSM and the IMSI is sent to the CSE and the service logic execution is started. Thereafter CAMEL specific handling is initiated, see figure above.

Contents of each CAMEL Phase

CAMEL phase 1:

1.1 CAMEL phase 1 functionality:

Functionality Purpose / supports Restrictions

Triggering on MO, MT and forwarded calls.

Call screening Simple VPN Call Forwarding Call Redirection Call Rerouting

Homing of pre-paid calls to HPLMN

No IN announcements supported

No charging operations Limited set of detection

points, e.g. the hunting services are not possible.

MT calls trigger in the GMSC only.

Not possible to activate Call Forwardings with VPN short codes.

Any Time Interrogation

The CSE may request HLR to provide subscriber status and/or location information at any time.

The exact location may not be up-to-date unless the mobile has an active call ongoing.

CS only

CAMEL phase 2:

2.1 CAMEL phase 2 functionality:

Functionality Purpose / supports Restrictions

Triggering on MO, MT and forwarded calls.

Call screening VPN for calls Call Forwarding Call Redirection Call Rerouting Follow-on calls In-band user interaction

(DTMF)

Tones and announcements

MT calls trigger in the GMSC only.

Charging operations

Pre-paid (MO, MT, CF) Free-phone Premium rate Personal Discount Location Dependent

discount

Reverse Charging

-

CSE provided e-parameters MO AoC -

New detection points (Abandon, Busy, NotReachable, NoAnswer, RouteSelectFailure cases)

Cleaner termination of relationship.

Better pre-paid service.

Hunting type of services.

-

Triggering criteria To reduce CSE & SSP

load-

Any Time Interrogation

The CSE may request HLR to provide subscriber status and/or location information at any time.

The exact location may not be up-to-date unless the mobile has an active call ongoing.

No call supervision

USSD communication between MS and CSE

USSD call-back for pre-paid roaming

Control & enquiry of IN services

Control of north American carrier information

Enhances pre-paid CSE based carrier

selection

Selecting correct long distance network for user interaction

Notification of supplementary service (CCBS, ECT, CD and MPTY) invocation to CSE

Fraud control

3 CAMEL phase 3:

3.1 CAMEL phase 3 functionality:

FunctionalityPurpose / supports

Triggering on MO, MT and forwarded calls.

Call screening Full VPN Call Forwarding Call Redirection Call Rerouting Follow-on calls In-band user interaction (DTMF)

Tones and announcements

Charging operations

Pre-paid (MO, MT, CF) Free-phone Premium rate Personal Discount Location Dependent discount

Reverse Charging

CSE provided e-parameters

CAMEL2 new detection points (Abandon, Busy, NotReachable, NoAnswer, RouteSelectFailure cases)

Cleaner termination of relationship. Better pre-paid service.

Hunting type of services.

CAMEL3 new trigger detection points. To trigger on demand only, e.g. for hunting

services.

Triggering criteria To reduce CSE & SSP load

Any Time Interrogation. Enhanced with CAMEL3 current location retrieval, and ATI for GMLC.

The CSE may request HLR to provide subscriber status and/or location information at any time.

 

USSD communication between MS and CSE

USSD call-back for pre-paid roaming

Control & enquiry of IN services

Control of north American carrier information

Enhances pre-paid CSE based carrier selection

Selecting correct long distance network for user interaction

Notification of supplementary service (CCBS, ECT, CD and MPTY) invocation to CSE

Fraud control

Call Gapping To control CSE overload situations within

HPLMN

MT call triggering in VMSC-B

To control MT supplementary services (CW, hold, CF, CD, ECT, MPTY)

Pre-paid for MT air-time charge (1st minute free, e.g. in USA)

Abandon as an EDP-R Improves charging

Enhanced FreeFormatCharging data (40 octets -> 160 octets)

Makes the CSE service logic easier

Reporting of MSRN/FTN to CSE Charging control of optimally routed calls

CSE-HLR interface: ATM/ATSI/NSDC

Multiple Subscriber Profile phase 2 CSE can control CF, barring supplementary

services. Off-line subscription control based on

VPLMN / time-of-day

Virtual operators

Subscribed dialled services (D-CSI) HPLMN specific service numbers

Serving Network Dialled services (N-CSI) VPLMN specific service numbers

MO SMS control (CS+PS)

Enhances pre-paid.

Enhances VPN

Inter-working with GPRS GPRS pre-paid

CS Mobility management notifications CSE can monitor location / reachability

Service Interaction Indicators

CSE can control inter-working with supplementary services (CW, hold, CF, CD, ECT, MPTY).

Multiple subscriber profile phase 2

CAMEL phase 4:

4.1 CAMEL phase 4 functionality in Release 5:

Functionality Purpose / supports Restrictions

Triggering on MO, MT and forwarded calls.

Call screening Full VPN Call Forwarding Call Redirection Call Rerouting Follow-on calls In-band user interaction

(DTMF)

Tones and announcements

Charging operations

Pre-paid (MO, MT, CF) Free-phone Premium rate Personal Discount Location Dependent discount

Reverse Charging

CSE provided e-parameters MO & MT AoC

CAMEL2 new detection · Cleaner termination of

relationship.

points (Abandon, Busy, NotReachable, NoAnswer, RouteSelectFailure cases)

· Better pre-paid service.

· Hunting type of services.

CAMEL3 new trigger detection points.

· To trigger on demand only, e.g. for hunting services.

Triggering criteria · To reduce CSE & SSP load

Any Time Interrogation. Enhanced with CAMEL3 current location retrieval, and ATI for GMLC. CAMEL4 enhances this to PS domain.

The CSE may request HLR to provide subscriber status and/or location information at any time.

 ATI for GMLC

USSD communication between MS and CSE

USSD call-back for pre-paid roaming 

Control & enquiry of IN services

Control of north American carrier information

Enhances pre-paid·  CSE based carrier selection

Selecting correct long distance network for user interaction

Notification of supplementary service (CCBS, ECT, CD and MPTY) invocation to CSE

· Fraud control

Call Gapping · To control CSE overload

situations within HPLMN

For CS calls only. Not for SMS or GPRS.

MT call triggering in VMSC-B

· To control MT supplementary services (CW, hold, CF, CD, ECT, MPTY)

· Pre-paid for MT air-time charge (1st minute free, e.g.

in USA)

Abandon as an EDP-R · Improves charging

Enhanced FreeFormatCharging data (40 octets -> 160 octets)

· Makes the CSE service logic easier

Reporting of MSRN/FTN to CSE

· Charging control of optimally routed calls

CSE-HLR interface: ATM/ATSI/NSDC

Multiple Subscriber Profile phase 2

CSE can control CF, barring supplementary services.

Off-line subscription control based on VPLMN / time-of-day

Virtual operators

Subscribed dialled services (D-CSI)

· HPLMN specific service numbers

· No call supervision

Serving Network Dialled services (N-CSI)

· VPLMN specific service numbers

· No call supervision

SMS control (CS+PS)

· Enhances pre-paid.

· Enhances VPN· Not content based

Inter-working with GPRS · GPRS pre-paid· Not content based

CS Mobility management notifications

· CSE can monitor location / reachability

Service Interaction Indicators

· CSE can control inter-working with supplementary services (CW, hold, CF, CD, ECT, MPTY).

· Multiple subscriber profile phase 2

Interactions with Optimal Routing

· CSE can control usage of OR

Call Party Handling

Wake-up calls  Conference calling Parallel hunting Click-to dial

IN based CCBS

Mid call procedure for MO and MT calls

 Control CPH configuration during call.

Automatic call collect

CAMEL for IMS

IMS pre-paid

Convergence to CS and GPRS services

Inclusion of flexible tone injection

Enhancements of pre-paid warning tones

Various informative tones

 

Provision of location information of called subscriber (Alerting phase)

The location of B-subscriber at the beginning of the call provided to service logic

Notification of GPRS mobility management to CSE

CSE can monitor location / reachability in PS side

Inclusion of ODB data in the CSE-HLR interface

Enhancement of MSP ph 2

Location information during an ongoing call (Handover DP)

Charging based on current location, for inter-PLMN and/or inter-system handovers

Transfer of the IMEI (with software version) and MS class mark to the CSE

allow the gsmSCF to determine information about the capabilities of the ME

Any Time Interrogation from CSE to MNP-SRF

Number portability query for prepay calls

Partial implementation of CAMEL phase 4

A functional entity (VMSC, GMSC or SGSN) may support the complete CAMEL phase4 functionality or, as a network option, it may support the complete CAMEL phase3 functionality and a partial implementation of CAMEL phase4.

4.2 CAMEL phase 4 additions in Release 6

Enhancements of Dialled Services ·Full control of Dialled Services 

Full CAMEL4 prepay support for SCUDIF

·The capability to report basic service code changes during ongoing call.

 

Change of position procedure armed with criteria

· Technical enhancement to reduce the signalling load 

Concluding Remarks

We have covered some basic details of CAMEL in this tutorial. As mentioned in the beginning, this is just an introductory tutorial. Below is the list of references that an interested reader can use to expand their knowledge of the topic. [1] provides the basics of CAMEL procedures and the way they are applied during call processing. [7] gives ideas on how to implement VoIP in 3G networks based on CAMEL. Interested user can have a look at [7] for details. [3] gives details about CAMEL Application Part (CAP). [2] provides in-depth implementation related stuff for CAMEL. 

References

[1] 3GPP TS 22.078: CAMEL Service Description; Stage 1

[2] 3GPP TS 23.078: CAMEL Phase 4; Stage 2

[3] 3GPP TS 29.078: CAMEL Phase 4; CAMEL Application Part (CAP) specification

[4] 3GPP: Contents of each CAMEL phase

[5] 3GPP TS 23.278: CAMEL Phase 4 - Stage 2; IM CN Interworking

[6] 3GPP TS 29.278: CAMEL Application Part (CAP) Specification for IP Multimedia Subsystems (IMS)

[7] 3GPP TR 21.978: Feasibility Technical Report - CAMEL Control of VoIP Services

[8] Wireless Intelligent Networking by G. Christensen, P. Florack and R. Duncan

[9] 3G service control; M.D.Cookson and D.G.Smith - BT Technological Journal, Vol 19, No. 1, Jan 2001

[10] IP Support in 3G systems; Snehamoy Banarjee and Dr. Dheeraj Sanghi - Indian Institute of Technology, Kanpur

[11] What is CAMEL? - WAP Insight

[12] Is the CAMEL standard stranded in the desert? - Communications Week International, May 7, 2001

[13] Open Service provisioning in GSM - Eckhard Geulen, Jens Hartmann

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