KR100565623B1 - Method for deleting GPRS Tunnel Protocol Resource - Google Patents

Abstract

The present invention provides a PDP context deletion request (Delete PDP), which is one of a GPRS Tunnel Protocol Control message (hereinafter, referred to as a "GTP-C") that is transmitted between a Serving GPRS Support Node (SGSN) and a GPRS Gateway Serving Node (GGSN). The present invention relates to a packet service providing method of a mobile communication system that can minimize the number of retransmissions of a request message when a delete PDP context response, which is a reception response message of a context Requset, is lost, and includes SGSN and GGSN. In the method of releasing a radio resource of a mobile communication system, the GGSN receiving the PDP context deletion request message from the SGSN deletes the PDP context, and transmits a response message to the SGSN to the SGSN; If the SGSN fails to receive the response message due to the loss of the response message, the SGSN will set an Extension Value in the SGSN. Retransmitting a PDP context deletion request message to the GGSN by designating a TEID, and setting the TEID of the PDP GTP header to the TEID specified in the extension value, thereby transmitting a response message to the PDP context deletion request. Transmitting to the SGSN, and the SGSN confirms that the TEID of the GTP header is the TEID assigned by the SGSN in the response message, thereby releasing the radio resource corresponding to the TEID, and transitioning the PDP context state to an inactive state. Including the steps.

Mobile communication system, radio resource release method

Description

Method for deleting radio resources in mobile communication system {Method for deleting GPRS Tunnel Protocol Resource}

1 is a configuration block diagram of a mobile communication system for providing a general packet service

2 is an explanatory diagram showing a message transmission and reception relationship between SGSN and GGSN in a mobile communication system according to the prior art;

3A to 3B are flowcharts illustrating a method for retransmitting a GTP-C packet data protocol context deletion request message in a mobile communication system according to the related art.

4A to 4B are flowcharts illustrating a radio resource release method in a mobile communication system according to the present invention.

The present invention relates to a General Packet Radio Service (GPRS) network providing a packet service of a mobile communication system, wherein a GTP control message (GPRS Tunnel Protocol Control) is transmitted between a Serving GPRS Support Node (SGSN) and a GPRS Gateway Serving Node (GGSN). The number of retransmissions of the request message when the PDP context response, which is a reception response message of the Delete PDP context Requset, which is one of the following "GTP-C" is lost. The present invention relates to a packet service providing method of a mobile communication system that can be minimized.

In general, a mobile communication switch can be classified into a packet switch providing a packet service such as an Internet connection and a circuit switch in charge of a service such as an existing telephone network, depending on the type of service.

Among them, the configuration of a conventional communication system that provides a packet service is as follows.

1 is a configuration block diagram of a mobile communication system for providing a general packet service.

As shown in FIG. 1, the mobile communication system providing the packet service includes a packet gateway switching station (GGSN) 6, a mobile communication packet switching station (SGSN) 3, It consists of a Home Location Register (HLR) 4 and a Universal Terrestrial Radio Access Network (UTRAN) 2. Here, reference numerals denote the Internet Protocol network 7, the GPRS network 5, and the mobile terminal 1, which is a terminal of a subscriber capable of receiving packet services.

 The Packet Gateway Switching Station (GGSN) 6 performs the function of a gateway for connection between the GPRS network 5 and the Internet network 7 (or an external packet network), and the Mobile Communication Packet Switching Station (SGSN) ( 3) is connected to the Packet Gateway Switching Station (GGSN) 6 through a GPRS network 5 to manage the mobility of the mobile terminal 1 in packet mode and to perform the function of a packet switch. The home location register (HLR) 4 is connected to the mobile communication packet switching station (SGSN) 3 to manage subscription information and location information of packet service subscribers, and the UTRAN 2 manages radio resources. It is to transfer data by allocating traffic channel.

A radio resource allocation and release process in a mobile communication system providing a general packet service having such a structure is as follows.

In order to receive GPRS, a packet service, a packet service subscriber must first register his location with the SGSN 3 using his mobile terminal 1. When the subscriber's location is registered from the mobile terminal 1 in this way, the SGSN 3 obtains the subscriber's service information from the home location register 4.

The SGSN 3 performs an activation procedure of a packet data protocol (hereinafter referred to as PDP) context for establishing a packet session. That is, radio resources are allocated between the mobile terminal 1 and the UTRAN 2 according to the desired Quality of Service.

When a packet session is established through the packet data protocol context activation procedure, a packet service may be provided to the mobile terminal 1.

Thereafter, if the subscriber wants to terminate the packet service, the SGSN 3 deactivates the packet data protocol context and releases the allocated radio resource through a packet data protocol context deactivation procedure.

At this time, the SGSN 3 sets a Tunnel Endpoint Identified (TEID) assigned by the GGSN 6 to transmit a packet data protocol context delete request message to the GGSN 6. To pass. The GGSN 6 receiving the packet data protocol context delete request message deletes the packet data protocol context for the corresponding TEID, and responds to the packet data protocol context deletion request (Delete PDP). A context response is sent to the SGSN 3 to release radio resources that have been allocated to the user.

That is, the packet data protocol context deletion request message may be defined by a GPRS tunnel protocol (GTP header) and an information element (IE), and the information element (IE) may be “Teardown Ind” or “NSAPI”. (Network layer Service Access Point Indicator) "and" Private Extension ".

The response message is defined by a GTP header and an information element IE, which is defined as "Cause."

Accordingly, the SGSN 3 sets the Tunnel Endpoint Identified (TEID) assigned by the GGSN 6 to the TEID of the GTP header (GTP Header-TEID = TEID (by assigned GGSN)). Of the information elements (IE), "Teardown Ind" is set to "0" or "1" (Teardown Ind = 0 or 1), "NSAPI" is set between "5" and "15" (NSAPI = 5), "Private Extension" delivers a Delete PDP context request message to the GGSN 6 in a state of not being set (Private Extension = not used). The GGSN 6 that receives the above packet data protocol context delete request message deletes the packet data protocol context corresponding to the TEID, and the GGSN 6 deletes the packet data protocol context deletion request. A response message (Delete PDP context response) is sent to the SGSN 3 to release the radio resources that have been allocated to the user. At this time, the response message is set to the TEID of the GTP header to the TEID assigned by the SGSN (3) and the response message that has set (Cause = accepted) to accept "Cause" of the information element is the GGSN (6) ) To SGSN (3).

However, the SGSN 3 requests the GGSN 6 to delete a packet data protocol context so that the GGSN 6 deletes the packet data protocol context and responds to the request for deleting the packet data protocol context (Delete PDP context). Although a response is transmitted to the SGSN 3, there may be a case where the response message (Delete PDP context response) is lost and not received by the SGSN 3. At this time, the SGSN (3) waits for the response message (Delete PDP context response) from the GGSN (6) and if the response waiting time is expired to repeatedly send a packet data protocol delete request message to the GGSN (6) do.

Therefore, the packet data protocol context deletion request message is set to repeat as many times as possible in the above process.

A conventional method of retransmitting such a packet data protocol context deletion request message will be described with reference to the accompanying drawings.

2 is an explanatory diagram illustrating a message transmission / reception relationship between a SGSN and a GGSN according to the prior art, and FIGS. 3A to 3B are flowcharts illustrating a method of retransmitting a GTP-C packet data protocol context deletion request message according to the prior art.

First, when the count value is initialized (Retry counter = 0), and the SSGN 3 does not receive a Delete PDP context Response from the GGSN 6 in response to a Delete PDP context Request. It is set to resend the delete request message five times (N3 Requests = 5) (1S).

If the subscriber wants to terminate the packet service, the SGSN 3 sets a tunnel endpoint identifier (TEID) assigned by the GGSN 6 to request the GGSN 6 to delete a packet data protocol context ( Delete PDP context request) message is transmitted (2S). That is, the tunnel termination identifier (TEID) assigned by the GGSN 6 is set as the TEID of the GTP header (GTP Header-TEID = TEID (by assigned GGSN)), and "Teardown Ind" of the information element (IE) is Set to "0" or "1" (Teardown Ind = 0 or 1), "NSAPI" to between "5" and "15" (NSAPI = 5), "Private Extension" not set (Private) Extension = not used) transmits a PDP context deletion permanent message from SGSN (3) to GGSN (6).

The GGSN 6 receiving the Delete PDP context request message deletes the packet data protocol context for the corresponding TEID (3S), and responds to the packet data protocol context delete request. (Delete PDP context response) is transmitted to the SGSN 3 (4S).

In this case, the response message is a message in which the TEID assigned by the SGSN 3 is set as the TEID of the GTP header, and the acceptance of "Cause" of the information element is set (Cause = accepted).

At this time, if the response message (Delete PDP context Response) is received by the SGSN (5S), the radio resource allocated to the user is released (13S), and the PDP context state is set to IN-ACTIVE state. Transition (14S) ends.

However, when the response message is sent to the SGSN 3 by the GGSN 6, but the response message is lost and the SGSN 3 does not receive the response message (5S), the SGSN 3 is set. When the retransmission count value is smaller than the set retransmission count N3 Requests (6S), the retransmission count value is 1 compared with the retransmission count N3 Requests and the retry count value Retry counter. Increment (Retry counter = Retry counter + 1) (7S), and resend the PDP context deletion request message to the GGSN 6 (8S).

Here, the PDP context delete re-request message, the TEID assigned by the GGSN (6) to the TEID of the GTP header (Header), Teardown Ind is "0" or "1" and NSAPI is between 5 and 15 Set this to an appropriate value and do not set "Private Extension" (Private Extension = not used).

The SGSN 3 drives a T3 Response Timer for the PDP context deletion request (9S).

Receiving the Delete PDP context request message, the GGSN 6 confirms that the PDP context associated with the TEID of the GTP header has already been deleted, sets the TEID of the GTP header to "0", and sets Cause to "." Non Exsistent "is transmitted to the SGSN 3 in response to the PDP context delete request (Delete PDP context response) (10S).

Upon receiving the response message from the GGSN 6, the SGSN 3 confirms that the TEID of the GTP header is "0" in the response message and ignores the response message (11S).

Since the response message is ignored, the standby timer driven in the step 9S is expired (T3 Response Timer Expired) 12S, and the steps 6S-12S are repeated.

By repeating the steps 6S-12S as described above, if the retry count value (Retry counter) is equal to the set number of retransmissions (N3 Requests) (6S), the SGSN (3) is a radio resource that has been allocated to the user. Is released (13S), the PDP context state is transitioned to an inactive state (14S) and ends.

However, in the conventional mobile communication system as described above, the radio resource allocation and release process has the following problems.

That is, when the response message for the first PDP context deletion request message is transmitted from the GGSN to the SGSN, but the response message is lost and not received by the SGSN, the PDP context deletion request message and the response number are set as many times (5). Since the radio resource allocated to the user is released after the response message is repeated, it takes a lot of time.

The present invention has been made to solve the above-mentioned problems. When retransmitting the PDP context deletion request message between SGSN and GGSN, the repetition number is used only once by utilizing a "Private Extension" which is a GPT-C information element. It is an object of the present invention to provide a radio resource release method in a mobile communication system that can be implemented.

Radio resource release method in a mobile communication system according to the present invention for achieving the above object, in the radio resource release method of a mobile communication system having SGSN and GGSN, receiving a PDP context deletion request message from the SGSN The GGSN deletes the corresponding PDP context, sends a response message to the SGSN to the deletion request, and if the SGSN fails to receive the response message because the response message is lost, the SGSN is assigned to the Extension Value. Retransmitting a PDP context deletion request message to the GGSN by designating a TEID assigned by the SGSN; and setting the TEID of the PDP GTP header to the TEID specified in the extension value by the GGSN for the PDP context deletion request. Characterized in that it comprises the step of sending a response message to the SGSN.

In this case, the SGSN confirms that the TEID of the GTP header is the TEID assigned by the SGSN in the response message, thereby releasing a radio resource corresponding to the TEID, and transitioning the PDP context state to an inactive state. There is this.

A preferred embodiment of a radio resource release method in a mobile communication system according to the present invention having the above characteristics will be described with reference to the accompanying drawings.

Since the configuration of the mobile communication system according to the present invention is the same as described with reference to FIG.

4A through 4B are flowcharts illustrating a radio resource release method in a mobile communication system according to the present invention.

First, when the count value is initialized (Retry counter = 0), and the SSGN 3 does not receive a Delete PDP context Response from the GGSN 6 in response to a Delete PDP context Request. Set to retransmit the delete request message five times (N3 Requests = 5) (101S).

If the subscriber wants to terminate the packet service, the SGSN 3 sets a Tunnel Endpoint Identified (TEID) assigned by the GGSN 6 to request the GGSN 6 to delete a packet data protocol context ( Delete PDP context request) message is transmitted (102S). That is, the tunnel termination identifier (TEID) assigned by the GGSN 6 is set as the TEID of the GTP header (GTP Header-TEID = TEID (by assigned GGSN)), and "Teardown Ind" of the information element (IE) is Set to "0" or "1" (Teardown Ind = 0 or 1), "NSAPI" to between "5" and "15" (NSAPI = 5), "Private Extension" not set (Private) Extension = not used) transmits a PDP context deletion permanent message from SGSN (3) to GGSN (6).

The GGSN 6 having received the Delete PDP context request message deletes the packet data protocol context for the corresponding TEID (103S), and responds to the packet data protocol context delete request. (Delete PDP context response) is transmitted to the SGSN 3 (104S).

In this case, the response message is a message in which the TEID assigned by the SGSN 3 is set as the TEID of the GTP header, and the acceptance of "Cause" of the information element is set (Cause = accepted).

At this time, if the response message (Delete PDP context Response) is received by the SGSN (105S), the radio resource allocated to the user is released (114S), and the PDP context state is transitioned to the inactive state (115S). Quit.

However, when the response message is transmitted to the SGSN 3 by the GGSN 6, but the response message is lost and the SGSN 3 does not receive the response message (105S), the SGSN 3 is set. When the retransmission count value (Retry counter) is smaller than the set number of retransmissions (N3 Requests) by comparing the retransmission count (N3 Requests) and the retransmission count value (Retry counter), the retransmission count value is 1. Increment (Retry counter = Retry counter + 1) 107S.

When the retransmission count value is greater than 0 (108S), the SGSN 3 retransmits the PDP context deletion request message to the GGSN 6 (109S).

Here, the PDP context delete re-request message, the TEID assigned by the GGSN (6) to the TEID of the GTP header (Header), Teardown Ind is "0" or "1" and NSAPI is between 5 and 15 Set to an appropriate value, specify "LGE" in "Extension Identifier" among the components of "Private Extension Information" (Extension Identifier = LGE), and in "SGt (3)" in "Extension Value" Specifies the assigned TEID (Extension Value = TEID by SGSN).

The SGSN 3 drives a T3 Response Timer for the PDP context deletion request (110S).

Receiving the Delete PDP context request message, the GGSN 6 confirms that the PDP context associated with the TEID of the GTP header has already been deleted, and displays the Private Extension information of the PDP context delete request retransmission message. After confirming, the TEID of the GTP header is set to "TEID" specified in the "Extension Value" (GTP Header-TEID = TEID (Exension Value)), and the Cause is set to "Non Exsistent" to the request for deleting the PDP context. A response message (Delete PDP context response) is transmitted to the SGSN 3 (111S).

Upon receiving the response message from the GGSN 6, the SGSN 3 confirms that the TEID of the GTP header is the TEID assigned by the SGSN in the response message and recognizes that the response message has been normally received (112S).

In addition, the SGSN 3 cancels the standby timer driven in the step 110S (113S), releases the radio resource allocated to the user (114S), and deactivates the PDP context state. Transition to 115S and ends.

The radio resource release method in the mobile communication system according to the present invention as described above has the following advantages.

That is, after the first PDP context deletion request message, when requesting deletion of the PDP context by retransmission from SGSN to GGSN, a request is made by specifying a TEID assigned by SGSN in private extension information, and when the response message is transmitted from SGSN to SGSN, Reply by setting TEID specified in Private Extension information to TEID of GTP header.

Accordingly, since the PDP context deletion request message is retransmitted only once without retransmitting as many times as the deletion request message is retransmitted (N3 Requests = 5), the load can be reduced and the radio resource release time can be shortened.

Claims (2)

In the radio resource release method of a mobile communication system having a SGSN and GGSN, Receiving, by the GGSN, a PDP context deletion request message from the SGSN, and deleting a corresponding PDP context, and transmitting a response message to the SGSN to the SGSN; If the SGSN fails to receive the response message because the response message is lost, the SGSN retransmits the PDP context deletion request message to the GGSN by specifying a TEID assigned by the SGSN in an extension value; And setting, by the GGSN, the TEID of the PDP GTP header to the TEID specified in the extension value, and transmitting a response message to the SGSN to the SGSN. . The method of claim 1, The SGSN confirms that the TEID of the GTP header is a TEID assigned by the SGSN in the response message, thereby releasing a radio resource corresponding to the TEID, and transitioning the PDP context state to an inactive state. The radio resource release method of the mobile communication system.

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