WO2007091819A1

WO2007091819A1 - Method and system for charging in multi-pdp enviroment

Info

Publication number: WO2007091819A1
Application number: PCT/KR2007/000630
Authority: WO
Inventors: Woo-Hyung Choi; Sang-Man Bak
Original assignee: Ktfreetel Co., Ltd.
Priority date: 2006-02-07
Filing date: 2007-02-06
Publication date: 2007-08-16
Also published as: GB0814802D0; KR100727077B1; JP2009526465A; GB2449790A; HK1122923A1; GB2449790B; JP4729107B2

Abstract

The present invention is related to a charging method and system in a multi-PDP context environment. The method, which is carried out in a GGSN connected to an SGSN and an AAA server via a network, includes (a) receiving a PDP context creating request message from the SGSN if there is a request for activating an additional PDP context from a subscriber's terminal created with at least one PDP context; (b) linking with the AAA server to authenticate a subscriber and generating a charging ID; (c) creating an account session ID of the additional PDP context if the authentication is successful, and creating a first account multi-session ID as the same value as the account session ID of a fist PDP context; and (d) transferring an account start request including the account session ID and the first multi-session ID to the AAA server, whereas the AAA server recognizes the receiving of the account start request of the additional PDP context as a charging in the same call accessing. With the present invention, charging data of a plurality of PDP contexts can be correlated to each other in the multi-PDP context environment.

Description

[DESCRIPTION]

[Invention Title]

METHOD AND SYSTEM FOR CHARGING IN MULTI-PDP

ENVIROMENT

[Technical Field]

The present invention is related to a charging method and system in a

multi-PDP environment, more specifically to a method and system that can efficiently

perform the charging in a WCDMA GPRS network providing various multi-PDP

context environments.

[Background Art]

The wideband code division multiple access (WCDMA), which refers to a

method using a wider band than a CDMA method, which uses a pseudo-noise code

indigenous to a subscriber's communication channel, is little affected by

frequency-selective fading due to the use of a wideband. If the same data is transmitted,

the bandwidth is increased, thereby increasing the processing gain, and thus the

interference is decreased as much as the increase of the processing gain, to thereby

increase the capacity.

Also, since the WCDMA can decompose a multipath by using a RAKE receiver, even a micro cell can overcome the electric wave delay of indoor surroundings.

The WCDMA has the high bandwidth efficiency per 1 mega Hz bandwidth, to thereby

have the benefit in capacity and increase the processing gain. Accordingly, the cost for

realizing can be decreased by reducing the size of a power amplifier, and the power

consumption and size of a terminal can be decreased by reducing the size of a power

amplifier. Thus, the WCDMA is a third generation communication system, which is

employed in Japan and Europe as well as Korea.

This WCDMA technology guarantees high speed transmission of packet data.

The general packet radio service (GPRS) defines a network structure and service for

providing packet data service.

A mobile station (MS) can receive the packet data service from a WCDMA

GPRS network through a PDP context.

The WCDMA GPRS network provides various multiple packet data protocol

(PDP) context environments. For example, the multiple PDP context environments can

include watching a particular video (a second PDP context) of Internet navigation (a

first PDP context) or separating an IMS SIP signal and actual traffic (e.g. voice, data,

and message) in the case of IP multimedia subsystem (IMS).

Also, in the multiple PDP context environments, an MMS can be used by

opening a separate PDP context besides the current PDP context if the MMS message is

received while browsing or downloading. Moreover, a separate PDP context can be used to transmit separate data, such as a message or a picture, while carrying out voice

or video communication, like VoIP.

In the multiple PDP context environments, the PDP context can be classified

into a secondary PDP context, sharing an access point number (APN) and an IP address

allotted to the subscriber, and a primary PDP context, allotting a separate APN and a

new IP address.

A packet corresponding to each PDP context is gathered by a serving GPRS

support node (SGSN) and a gateway GPRS support node (GGSN) by using an

international mobile subscriber identity (IMSI) and a network layer service access point

identifier (NSAPI) as a key.

At this time, whenever a call or a session is created, a key for charging allots a

charging ID to provide it to the SGSN in the GGSN. The charging ID is transferred to a

charging gateway (CG) and an authentication authorization accounting (AAA). The CG

and the AAA perform the charging by using the charging ID to charge for the packet

received by the subscriber.

However, the charging ID functions to merely identify each PDP session. The

charging ID is not able to cover various sessions (PDP contexts) generated after the

subscriber creates a call.

In other words, using only the charging ID in accordance with the prior art is

not able to make it to correlate each session in the multiple PDP context environment. Typically, a network operator can not only share the APN but also provide

variously differentiated services by using strong points of the multiple PDP context

environment and making a difference in the quality of service (QoS) per PDP context.

The service can be completely separated by changing the APN and allotting a separate

IP address.

The subscriber attempts to make a call in the multiple PDP context

environments having the aforementioned benefits. Then, the subscriber employs the

multiple PDP context environments of the WCDMA GPRS to efficiently use various

services provided by the operator. However, in accordance to the prior art, since the key

for covering the multiple PDP context environments together is not standardized, the

charging information provided to the subscriber is calculated as if various calls are used.

Of course, the combination of the subscriber's number, the IP address allotted

to the subscriber and the usage time can be estimated as the charge for the PDP contexts

of the same call. However, this kind of estimation is improper for charging, in which

charging reliability is an important factor.

Also, it can be important for the operator to identify whether the subscriber

accesses a call many times or the subscriber requests various PDP contexts after

accessing the call one time, in order to develop and provide a separate product for

various fee patterns. For example, the subscriber may access the call twice and then use

each of the services A and B, or may access the call one time and generate two PDP contexts and then use the services A and B.

Especially, since the fee pattern of accessing one call and using various PDP

contexts becomes a current type service, this pattern should have been considered

differently in terms of providing the service and charging for the service, such as

prepayment deduction. However, the prior art has not been able to identify the request

of various PDP contexts, to thereby be unable to reflect the aspects as separate

consideration.

When charging, the prior art has also not been able to identify the request of

various PDP contexts after accessing one call because there has been no parameter

currently standardized when liking with a charging gate.

[Disclosure]

[Technical Problem]

Accordingly, the present invention, which is designed to solve the

aforementioned problems, provides a charging method and system in a multi-PDP

environment that can efficiently perform the charging in the case of accessing one call

and requesting various PDP contexts.

Also, the present invention provides a charging method and system in a

multi-PDP environment that can be applied for any one of a RADIUS charging method

and a CG charging method. In addition, the present invention provides a charging method and system in a

multi-PDP environment that can be also applied in a CDMA environment using

multiple service instances.

[Technical Solution]

To solve the above problems, according to an embodiment of the present

invention, there is provided a charging method in a multi-PDP environment, which is

carried out in a GGSN connected to an SGSN and an AAA server via a network

including (a) receiving a PDP context creating request message from the SGSN if there

is a request for activating an additional PDP context from a subscriber's terminal

created with at least one PDP context; (b) authenticating a subscriber by linking with

the AAA server, and generating a charging ID; (c) creating an account session ID of the

additional PDP context if the authentication is successful, and creating a first account

multi-session ID as the same value as the account session ID of a fist PDP context; and

(d) transferring an account start request including the account session ID and the first

multi-session ID to the AAA server, whereas the AAA server recognizes the receiving

of the account start request of the additional PDP context as a charging in the same call

accessing.

Preferably, the account session ID can be created as a combination of an IP

address of the GGSN and the charging ID. The method of the present invention can further include receiving at least one

PDP context deleting request message from the SSGN; and transferring a second

account multi-session ID of a deleted PDP context to the AAA server after deleting the

PDP context, the second account multi-session ID being set as the first account

multi-session ID created when the deleted PDP context is activated.

At this time, the PDP context is preferably deleted based on a teardown

indicator received from the SSGN.

Also, in the present invention, the GGSN is connected to a charging gateway,

and preferably, the method further includes creating a multi-charging ID as a charging

ID of the first PDP context of the additional PDP context

According to the present invention, the method can further include transferring

a message having a multi-charging ID field of a deleted PDP context to the charging

gateway after deleting the additional PDP context.

At this time, the message can be a data record transfer request message.

According to another embodiment of the present invention, there is provided a

recorded medium having recorded a program for executing the method, the recorded

medium being readable by a computer.

According to another embodiment of the present invention, there is provided a

GGSN, connected to an SGSN and an AAA server through a network, the GGSN

including an SGSN communication unit, receiving a PDP context creating request message from the SGSN if there is a request for activating an additional PDP context

from a subscriber's terminal created with at least one PDP context; an AAA server

communication unit, authenticating a subscriber by linking with the AAA server and

receiving and transmitting a message from and to the AAA server; a charging ID

generating unit, generating a charging ID for the additional PDP context if the

authentication is successful; and an account session ID generating unit, creating an

account session ID of the additional PDP context as a combination of an IP address of

the GGSN and the charging ID, and creating a first account multi-session ID as the

same value as the account session ID of a fist PDP context, whereas the AAA server

communication unit transfers an account start request including the account session ID

and the first account multi-session ID to the AAA server, and the AAA server

recognizes the receiving of the account start request of the additional PDP context as a

charging in the same call accessing.

At this time, preferably, the session ID generating unit transfers a second

account multi-session ID of a deleted PDP context to the AAA server if at least one

PDP context deleting request message is received from the SSGN, and sets a second

account multi-session ID as the first account multi-session ID of the deleted PDP

context.

Also, the GGSN preferably further includes a CG communication unit, being

connected to a charging gateway and receiving and transmitting a message; and a multi-charging ID field generating unit, creating a multi-charging ID as a charging ID

of a first PDP context of the additional PDP context.

According to another embodiment of the present invention, there is provided a

WCDMA GPRS system, which is a charging system in a multi-PDP environment, the

system including an SSGN, receiving a request for activating an additional PDP context

from a subscriber's terminal created with at least one PDP context; a GGSN,

authenticating a subscriber if a request message for activating the additional PDP

context is received corresponding to the activating request, creating an account

multi-session ID of the additional PDP context as a charging ID, an account session ID

and the account session ID of a first PDP context, and transmitting an account start

request including the ID; and an AAA server, recognizing the receiving of the account

start request of the additional PDP context as a charging in the same call accessing.

[Description of Drawings]

FIG. 1 illustrates the structure of a mobile communication network in

accordance with an embodiment of the present invention;

FIG. 2 is a block diagram illustrating the inside of a GGSN in accordance with

an embodiment of the present invention;

FIG. 3 and FIG. 4 are flow charts illustrating a service processing operation in

accordance with the present invention; FIG. 5 is a flow chart illustrating an operation of generating an account session

ID in accordance with an embodiment of the present invention; and

FIG. 6 is a flow chart illustrating an operation of generating a multi-charging

field in accordance with another embodiment of the present invention.

[Mode for Invention]

Hereinafter, some embodiments of a charging method and system in a

multi-PDP environment in accordance with the present invention will be described in

detail with reference to the accompanying drawings.

FIG. 1 illustrates the structure of a mobile communication network in

accordance with an embodiment of the present invention.

As illustrated in FIG. 1, the mobile communication network of the present

invention can include a node 102, a radio network controller (RNC) 104, a mobile

switching center (MSC) 106, a home location register (HLR) 108, a serving GPRS

support node (SGSN) 110, a gateway GPRS support node (GGSN) 112, an

authentication authorization accounting (AAA) server 114 and a charging gateway (CG)

116. A subscriber's terminal, which is a mobile station (MS) 100, can be configured to

primarily connect to the node 102 to receive various services.

Here, the node 102 and the RNC 104 pertain to a wireless access network

group, and the MSC 106 and the HLR 108 pertain to a circuit switching core network group. Also, the SGSN 110 and the GGSN 112 pertain to a packet switching core

network group.

In the wireless access network group, a limited wireless resource is efficiently

used to provide a high speed packet data service, and functions to satisfy various request

conditions for quality of service are performed in a multimedia system.

The MSC 106 pertained to the circuit switching core network group performs

the central control function to process a signal received and transmitted from each RNC

104 and to control the RNC 104 to be efficiently operated.

The HLR 108 stores all kinds of information related to a subscriber and

information related to a subscriber's additional service and an intelligent network

service provided to the subscriber.

The SGSN 110 and the GGSN 112, pertained to the packet switching core

network group, provide an IP-based protocol link to be connected with the Internet in

order that the MS 100, which is a wireless mobile communication terminal, receives the

packet switching service.

For this, the SGSN 110 is connected to various wireless network controllers

104 and manages the mobility of the MS 100 and packet session. With the GGSN, the

SGSN 110 creates the PDP context and transfers a protocol data unit by use of

tunneling.

Also, the SGSN 110 can perform an IP routing and be connected to a switch to perform the interaction such as the location registration of the MS 100.

The GGSN 112, which is a gateway directly accessing a packet network and

the Internet, maintains routing information with the SGSN 110 and an external network

and performs the tunneling and IP routing functions.

The AAA server 114 covers authentication, authorization and accounting

related to a packet data network and performs a charging function by using the remote

access dial-in user service (RADIUS) protocol.

The charging function can be performed by the charging gateway 116

independently or simultaneously with the AAA server 114. In case that the GGSN 112

accesses a call of the MS 100, the AAA server 114 and the charging gateway 116

receive a predetermined message and start to gather charging data, and perform the

charging for the usage of packet data till the deletion of the call is requested.

In the conventional charging process, if the subscriber requests to create a

plurality of PDP contexts based on one call accessing, since the creating of the plurality

of PDP contexts is not able to be correlated to the charging, the charging is performed

as if the call is separately accessed. However, in accordance with an embodiment of the

present invention, although there is a request for creating an additional PDP context

after the AAA server 114 and the charging gateway 116 access a call, this can be

considered as the charging for the same call.

If activation of the PDP context is requested by the subscriber in order to have the MS 100 receive a packet call service, the SGSN 110 transfers the subscriber's

request to the GGSN 112.

At this time, the GGSN 112 is linked with the AAA server 114 to authenticate

the subscriber. If the subscriber is successfully authenticated, a charging ID is generated,

and at the same time, a predetermined account session ID for identifying the created

session is created.

Preferably, the account session ID can be created as a combination of the

charging ID and the IP address created for the GGSN.

The GGSN 112 transfers an account start request including the charging ID to

the AAA server 114 after creating the charging ID. When the account start request is

received, the AAA server 114 starts to gather the charging data of the corresponding

subscriber.

As described above, since the WCDMA GPRS provides the multiple PDP

context environments, the subscriber can request to create an additional PDP context

after a call is accessed. If there is this request, the GGSN performs the generating

operation of the subscriber authentication, charging ID and account session ID of each

additional PDP context.

Also, the GGSN 112 of the present invention adds a predetermined parameter

to the additional PDP context such that the AAA server 112 can recognize the

additional PDP context is created in the same call accessing. An additional parameter of the present invention is an account multi-session ID.

The GGSN 112 creates the account multi-session ID of the additional PDP context as

the account session ID of a first PDP context and transfers to the AAA server 114 the

account start request including the account session ID of the additional PDP context and

the account multi-session ID.

The AAA server 114 recognizes that the account start request is the creating of

a different PDP context in one call session, by verifying that the account multi-session

ID of the additional PDP context is the same as the account session ID of the first PDP

context, previously transferred. Then, the AAA server 114 starts to gather

corresponding charging data. Later, the plurality of PDP contexts can be correlated to

each other.

Meanwhile, the charging process can be performed through the charging

gateway. The conventional charging gateway performs the charging process based on

the charging ID generated as described above. In accordance with the present invention,

however, the charging gateway can perform the charging process by using the

additional parameter as well.

If the subscriber who accesses a call requests to create the additional PDP

context, the GGSN 112 creates a separate multi-charging ID in addition to generating

the charging ID of the additional PDP context.

At this time, the multi-charging ID of the additional PDP context can be the charging ID that is associated with the first PDP context in one call accessing. If a

message having a multi-charging ID field is received, the charging gateway recognizes

that this is the charging in the same call accessing to perform the charging process.

Then, if the subscriber requests to delete at least one PDP context, the GGSN

112 deletes the pertinent PDP context and then transfers an account stop request to the

AAA server 114. At this time, the account stop request can include the account

multi-session ID of the deleted PDP context.

At this time, the account multi-session ID of the deleted PDP context is created

as the same value as the account session ID of the previously created first PDP context.

Accordingly, the AAA server 114 recognizes that the deleted PDP context is the context

created in one call accessing and performs the corresponding charging process.

Also, when deleting the PDP context, the GGSN 112 informs the charging

gateway 116 that at least one deleted PDP context is the charging for the same

call/session, by transferring a data record transfer request message including the

multi-charging ID to the charging gateway 116.

In accordance with the present invention, the parameter, provided as described

above, functions as the only key for identifying the overall charging session such that a

unit processing the charging can recognize a plurality of PDP contexts belong to the

context in one call accessing. Accordingly, a more efficient charging service can be

provided to the subscriber. FIG. 2 is a block diagram illustrating the inside of the GGSN in accordance

with an embodiment of the present invention.

As illustrated in FIG. 2, the GGSN of the present invention can include an

SGSN communication unit 200, a charging ID generating unit 202, an account session

ID generating unit 204, a multi-charging ID field generating unit 206, an AAA server

communication unit 208 and a CG communication unit 210.

The SGSN communication unit 200, which is configured to be connected to the

SGSN 110, receives a request message of creating a PDP context and a request message

of deleting a PDP context, transferred by the SGSN 110 according to the request of the

subscriber's terminal 100, and transmits responses according to the messages to the

SGSN I lO.

The charging ID generating unit 202 generates a charging ID of creating the

pertinent PDP context through liking with the AAA server 114 in the case of succeeding

in the authentication of the subscriber.

The charging ID can be transferred to the charging gateway 116.

After the GGSN 112 is linked with the AAA server 114 through the AAA

server communication unit 208 and performs the authentication process, the account

session ID generating unit 204 generates the account session ID, which becomes basic

data for gathering charging data in the case of succeeding in the authentication. Preferably, the account session ID can be generated as a combination of the charging ID

and the IP address of the GGSN 112.

In the meantime, the session ID generating unit 204 generates an account

multi-session ID independently of the account session ID. At this time, the account

multi-session ID is created as the account session ID of a first PDP context.

The session ID generating unit 204 generates the account multi-session ID in

case not only that the subscriber requests to create the PDP context but also that the

subscriber requests to delete the PDP context. The session ID generating unit 204 sets

the pertinent account multi-session ID as the account session ID of the previous first

PDP context to transfer it to the AAA server 114.

Accordingly, the AAA server 114 can recognize that this is the charging in the

same call accessing.

As described above, the charging can be performed through the charging

gateway 116. If the subscriber requests to delete at least one PDP context, the

multi-charging ID field generating unit 206 generates a multi-charging ID field

independently of the charging ID and writes the charging ID of the first PDP context in

the multi-charging ID field.

The data record transfer request message including the multi-charging ID field

can be transferred to the charging gateway 116 through the CG communication unit 210.

When the charging gateway 116 receives the message, the charging gateway 116 performs the charging by recognizing that each PDP context is the context in one call

accessing.

accordance with the present invention.

FIG. 3 and FIG. 4 illustrate the overall processes of a case in which a

subscriber's terminal firstly requests a packet call service and then requests to create an

additional PDP context. Referring to FIG. 3 and FIG. 4, the MS 100 transfers a PDP

context activating request to the SGSN 110 in a step represented by 300. The SGSN 110

then transmits a PDP context creating request to the GGSN 112 in a step represented by

302.

The GGSN 112 transmits an access request for authenticating the subscriber to

the AAA server 114 in a step represented by 304. In the case of succeeding in the

authentication, the AAA server 114 transmits the response to whether the authentication

is successful to the GGSN 112 in a step represented by 306.

The GGSN 112 performs a predetermined internal processing operation such as

IP allotment. Then, the SGSN 110 transmits to the SGSN 110 the response to the

request for creating the additional PDP context in a step represented by 308. At this

time, in the case of succeeding in the authentication, the GGSN 112 can generate a

charging ID by the creating of the PDP context and include the generated charging ID in the response of the step represented by 308.

The SGSN 110 transmits an activated PDP context accepting message to the

MS 100 in a step represented by 310. Accordingly, a packet data service can be

performed between the MS 100 and the GGSN 112. The MS 100 can receive and

transmit data from and to an application server in a step represented by 316.

Meanwhile, the GGSN 112 transfers an account start request to the AAA

server 114 in the case of succeeding in the authentication in a step represented by 312.

The AAA server 114 transmits a response to the account start request to the GGSN 112

in a step represented by 314.

At this time, the account start request can include the account session ID and

the account multi-session ID. The account session ID can be created as a combination of

the charging ID and the IP address the GGSN 112. The account multi-session ID can be

created as the same value as the account session ID.

Then, the subscriber can request to activate the additional PDP context to

receive another service. In this case, the MS 100 transmits a secondary PDP context

activating request or an additional main PDP context activating request to the SGSN

110 in a step represented by 318.

If the additional main PDP context activating request is received from the MS

100, the aforementioned steps (represented by 302 through 316) are repeatedly

performed. In accordance with the present invention, in the case of creating the additional

PDP context, the GGSN 112 creates the account multi-session ID of the additional PDP

context as the same value as the account session ID of a first PDP context and transmits

it to the AAA server 114 in a step represented by 322.

The AAA server 114 can recognize that a plurality of PDP contexts having

identical account multi-session IDs are the PDP contexts in one call accessing. When

charging data is generated, the charging data of the plurality of PDP contexts can be

correlated with each other.

In the meantime, if the subscriber requests to delete the call, the MS 100

transmits a request to deactivate at least one PDP context to the SGSN 110 in a step

represented by 330. The SGSN 110 transmits a PDP context deleting request to the

GGSN 112 in a step represented by 332.

At this time, the GGSN 112 deletes the PDP context, and then, transmits a

response to delete the PDP context to the SGSN 110 in a step represented by 334. The

SGSN 110 transmits a deactivated PDP context accepting message to the MS 100 in a

step represented by 336.

In the aforementioned PDP context deleting operation, the GGSN 112

transmits a data record transfer request to charging gateway 116 in a step represented by

338.

In accordance with the present invention, not only is the charging ID of the deleted PDP context added to the data record transfer request, but also the

multi-charging ID field is added. The multi-charging ID field is written with the

charging ID of the first PDP context such that the charging gateway 116 can identify the

PDP context in the same call accessing among the plurality of PDP contexts and

perform the charging.

Also, when the PDP context is deleted, the GGSN 112 transmits an account

stop request to the AAA server 114 in a step represented by 340. This request can also

include the multi-session ID, which is created as the account session ID of the first PDP

context such that the AAA server 114 can identify the PDP context in the same call

accessing among the plurality of PDP contexts.

Then, the charging gate way 116 and the AAA server 114 transmit a response

according to the receiving of the message to the GGSN 112 in steps represented by 342

and 344.

Meanwhile, the subscriber can request to delete another PDP context. If the

subscriber requests to deactivate another PDP context in a step represented by 344, the

same steps as the aforementioned steps (represented by 332 through 344) are repeatedly

performed in steps represented by 348 through 360.

FIG. 5 is a flow chart illustrating the process of generating the account session

ID in accordance with an embodiment of the present invention. FIG. 5 illustrates a process performed in case that a subscriber requests to

create a PDP context. Referring to FIG. 5, the GGSN 112 receives a request to create a

first PDP context from the SGSN 110 in a step represented by 500.

Then, the authentication is performed through linking with the AAA server. If

the authentication is successful, the charging ID of the PDP context is created in a step

represented by 502, and an account session ID is created as a combination of the

charging ID the IP address of the GGSN in a step represented by 504.

Also, the GGSN 112 sets an account multi-session ID, included in a message

transmitted to the AAA server 114, as the same value as the account session ID in a step

represented by 506.

On the other hand, in one call accessing, the subscriber can request to activate

an additional PDP context. If a request to activate the additional PDP context is received

in a step represented by 508, the GGSN 112 sets the account multi-session ID of the

additional PDP context as the same value as the account session ID of a first PDP

context in a step represented by 512 and provide it to the AAA server in addition to

repeatedly performing the aforementioned steps (represented by 502 and 504).

In accordance with the present invention, if a plurality of PDP contexts are

created in one call accessing, an identical account multi-session ID is allotted to the

plurality of PDP contexts such that the AAA server 114 can allow the plurality of PDP

contexts to be correlated to each other. On the other hand, FIG. 6 is a flow chart illustrating the process of generating a

multi-charging field in accordance with another embodiment of the present invention.

FIG. 6 illustrates a processing operation when a subscriber requests to deactivate a PDP

context.

Referring to FIG. 6, if a request to delete the PDP context is received in a step

represented by 600, the GGSN 112 processes the deleting operation of at least one PDP

context in a step represented by 602.

At this time, the GGSN 112 of the present invention creates an account

multi-session ID included in an account stop request transmitted to the AAA server 114

in a step represented by 604. This account multi-session ID is created as an account

multi-session ID generated when the PDP context is activated.

Then, a data record transfer request message is transmitted to charging gateway.

At this time, the GGSN adds a multi-charging ID field to the message in a step

represented by 606 and writes the charging ID of the first PDP context in the

multi-charging ID field in a step represented by 608.

In accordance with the present invention, a charging processing unit can allow

the plurality of PDP contexts to be correlated to each other by providing an additional

parameter capable of identifying that the plurality of PDP contexts are created in one

call accessing. This can allow efficient execution of the charging. Hitherto, although some embodiments of the present invention have been

shown and described for the above-described objects, it will be appreciated by any

person of ordinary skill in the art that a large number of modifications, permutations and

additions are possible within the principles and spirit of the invention, the scope of

which shall be defined by the appended claims and their equivalents.

[Industrial Applicability]

As described above, in accordance with the present invention, it is possible to

operate a flexible charging system because a plurality of PDP contexts can be identified

as the PDP contexts in one call accessing.

Also, the present invention can be applied for any one of an RADIUS charging

method and a CG charging method.

In addition, the present invention can be applied in a CDMA environment

using multiple service instances.

Claims

[CLAIMS]

[Claim 1]

A charging method in a multi-PDP environment, the method being carried out

in a GGSN connected to an SGSN and an AAA server via a network, the method

comprising:

(a) receiving a PDP context creating request message from the SGSN if there is

a request for activating an additional PDP context from a subscriber's terminal created

with at least one PDP context;

(b) authenticating a subscriber by linking with the AAA server, and generating

a charging ID;

(c) creating an account session ID of the additional PDP context if the

authentication is successful, and creating a first account multi-session ID as the same

value as the account session ID of a fist PDP context; and

(d) transferring an account start request including the account session ID and

the first multi-session ID to the AAA server,

whereas the AAA server recognizes the receiving of the account start request

of the additional PDP context as a charging in the same call accessing.

[Claim 2]

The method of Claim 1, wherein the account session ID is created as a combination of an IP address of the GGSN and the charging ID.

[Claim 3]

The method of Claim 1, further comprising:

receiving at least one PDP context deleting request message from the SSGN;

and

transferring a second account multi-session ID of a deleted PDP context to the

AAA server after deleting the PDP context, the second account multi-session ID being

set as the first account multi-session ID created when the deleted PDP context is

activated.

[Claim 4]

The method of Claim 3, wherein the PDP context is deleted based on a

teardown indicator received from the SSGN.

[Claim 5]

The method of Claim 1, wherein the GGSN is connected to a charging gateway,

and the method further comprises creating a multi-charging ID as a charging ID of the

first PDP context of the additional PDP context.

[Claim 6]

The method of Claim 5, further comprising transferring a message including a

multi-charging ID field of a deleted PDP context to the charging gateway after deleting

the additional PDP context.

[Claim 7]

The method of Claim 6, wherein the message is a data record transfer request

message.

[Claim 8]

A recorded medium having recorded a program for executing a method in

accordance with any one of claims 1 through 7, the recorded medium being readable by

a computer.

[Claim 9]

A GGSN, connected to an SGSN and an AAA server through a network, the

GGSN comprising:

an SGSN communication unit, receiving a PDP context creating request

message from the SGSN if there is a request for activating an additional PDP context

from a subscriber's terminal created with at least one PDP context;

an AAA server communication unit, authenticating a subscriber by linking with the AAA server and receiving and transmitting a message from and to the AAA

server;

a charging ID generating unit, generating a charging ID for the additional PDP

context if the authentication is successful; and

an account session ID generating unit, creating an account session ID of the

additional PDP context as a combination of an IP address of the GGSN and the charging

ID, and creating a first account multi-session ID as the same value as the account

session ID of a fist PDP context,

whereas the AAA server communication unit transfers an account start request

including the account session ID and the first account multi-session ID to the AAA

server, and the AAA server recognizes the receiving of the account start request of the

additional PDP context as a charging in the same call accessing.

[Claim 10]

The GGSN of Claim 9, wherein the session ID generating unit transfers a

second account multi-session ID of a deleted PDP context to the AAA server if at least

one PDP context deleting request message is received from the SSGN, and sets a second

context.

[Claim 11 ]

The GGSN of Claim 9, further comprising:

a CG communication unit, being connected to a charging gateway and

receiving and transmitting a message; and

a multi-charging ID field generating unit, creating a multi-charging ID as a

charging ID of a first PDP context of the additional PDP context.

[Claim 12]

A WCDMA GPRS system, which is a charging system in a multi-PDP

environment, the system comprising:

an SSGN, receiving a request for activating an additional PDP context from a

subscriber's terminal created with at least one PDP context;

a GGSN, authenticating a subscriber if a request message for activating the

additional PDP context is received corresponding to the activating request, creating an

account multi-session ID of the additional PDP context as a charging ID, an account

session ID and the account session ID of a first PDP context, and transmitting an

account start request including the ID; and

an AAA server, recognizing the receiving of the account start request of the

additional PDP context as a charging in the same call accessing.