KR20080080721A

KR20080080721A - Apparatus and method for preventing loss of user datagram protocol/internet protocol based a1 interface message in mobile telecommunication system

Info

Publication number: KR20080080721A
Application number: KR20070020768A
Authority: KR
Inventors: 정병기
Original assignee: 삼성전자주식회사
Priority date: 2007-03-02
Filing date: 2007-03-02
Publication date: 2008-09-05

Abstract

An apparatus and a method for preventing a loss of a user datagram protocol/Internet protocol-based A1 interface message in a mobile communication system are provided to transmit a message for checking a system state periodically to perform a call transfer when an error occurs, to thereby continuously provide a call connection. When A client(401) generates an A1 interface message and transmits it to a server(403), the client sets a sequence number of the message and transmits it to the server(410). The server sets a sequence number of a response message and transmits the message to the client(412). When the client generates a different A1 interface message and transmits it to the server, it sets a sequence number for the message, and transmits the same(430). When the sequence number of the message is set, the connection performed by the client or the server is sequentially increased from 1(432).

Description

Apparatus and method for preventing loss of user datagram protocol and internet protocol based one-way interface message in mobile communication system

1 is a diagram illustrating an A1,2 interface between a controller and an exchange in a conventional mobile communication system.

2 is a diagram illustrating a protocol stack of an A1 interface in a conventional mobile communication system.

3 is a diagram illustrating a process of establishing an A1 interface connection in a conventional mobile communication system;

4 is a diagram illustrating a process of delivering an A1 interface message in a mobile communication system according to an embodiment of the present invention;

5 is a diagram illustrating a call processing process through an A1 interface connection in a mobile communication system according to an embodiment of the present invention;

6 is a diagram illustrating a process of performing message retransmission according to a loss of an A1 interface message in a mobile communication system according to an embodiment of the present invention;

7 is a diagram illustrating an A1 interface message for supporting a UDP-based A1 interface in a mobile communication system according to an embodiment of the present invention;

8 is a diagram illustrating a process of processing a network failure in a mobile communication system according to an embodiment of the present invention;

9 is a diagram illustrating an A1 interface message for checking system status and system routing in a mobile communication system according to an embodiment of the present invention.

The present invention relates to an apparatus and method for an A1 interface section in a mobile communication system, and more particularly, to an apparatus and method for providing a continuous call service by preventing a message loss occurring in an A1 interface section of a mobile communication system. .

Referring to FIG. 1, in the standard standard of the existing mobile communication system (3GPP2 standard A.S0012-C_v1.0_050224), the controller (BSC; Base Station Controller) 110, 120 and the switch (MSC; Mobile Switching Center) ( 130) S7 (Singleam Control System / User Datagram Protocol) based on SS7 (Singnaling System 7) or IP (Internet Protocol) using the E1 / T1 link as the hardware protocol as the communication protocol of the A1 interface. It specifies its use.

The A1 interface is an interface for controlling user traffic in the A2 interface, which is a transmission path of data traffic, not a signal traffic between the controllers 110 and 120 and the exchange 130. The controllers 110 and 120 may include a base transceiver system (BTS) 110 and 120 according to an implementation situation, and the switch 430 may also include a media gateway controller (MGC) 130 according to an implementation situation. And a media gateway (MG) 135.

The MGC 130 plays a role of a media controller in a structure in which a media processor and a media controller are separated. The MG 135 plays a role of a media processor in a structure in which the media processor and the media controller are separated. Megaco Protocol is a protocol used by the MGC 130 in the H.248 standard.

2, in the standard, the E1 / T1 link 210 is used as the physical layer of the A1 interface and SS7 is used as the protocol of the data link layer. Signaling Connection Control Part / Message Transfer Part (SCCP / MTP) 220, 230 is a signal control related protocol of the SS7.

Base station application parts (BSAPs) 220 and 225 are divided into a direct transfer application part (DTAP) and a base station management application part (BSMAP), wherein the DTAP transmits a message transmitted by a mobile communication terminal to the controller (110, 120). A protocol provided to the exchange 130, and the BSMAP is a protocol for processing the A1 interface message between the controller (110, 120) and the exchange (130).

Although the SS7 performs link management, there is a limitation of the management range, and the SCTP also has a problem of delay and speed decrease due to a connection oriented method.

3 is a diagram illustrating a call processing process in an existing mobile communication system.

Referring to FIG. 3, the mobile communication system may be configured of a calling base station 301, a switch 303, and a receiving base station 305.

First, when a call connection request by a user occurs, the originating base station 301 transmits 310 a CM Service Request message (CM Service Request) for registration of a network access function to the exchange 303.

Thereafter, the exchange 303 transmits an assignment request 312 to the originating base station 301 to request radio resource allocation, and the base station 301 receiving the message completes the radio resource allocation. A notification message (Assignment Complet) is sent to the exchange 303 (314).

Thereafter, the exchange 303 performs a paging process 316 with the receiving base station 305 and then performs a call connection 318.

When UDP / IP is used in the conventional mobile communication system as described above, the order of the messages used in the mobile communication system cannot be guaranteed and the message is lost due to the failure of the mobile communication system.

Accordingly, there is a need for an apparatus and method for preventing message loss that may occur in such a mobile communication system.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus and method for preventing the loss of an A1 interface message in a mobile communication system.

Another object of the present invention is to provide an apparatus and method for preventing message loss using a response message of an A1 interface message in a mobile communication system.

According to a first aspect of the present invention for achieving the above objects, a mobile communication system using UDP / IP as a data link layer protocol for connection with a mobile switching center (MSC) to prevent the loss of the A-one interface message When receiving an A1 interface message for connection control from the exchange, a controller (BSC) for transmitting a response message to the exchange to the exchange, and a data link layer protocol for connection with the controller And using the UDP / IP, and receiving the A1 interface message for connection control from the controller, the switch for transmitting a response message to the controller.

According to a second aspect of the present invention for achieving the above objects, a method for preventing the loss of the A1 interface message based on User Datagram Protocol / Internet Protocol (UDP / IP) at the base station is A1 required for connection control with the exchange. Generating an interface message and transmitting the generated message to the exchange; if it is confirmed that a response message for the transmitted A1 interface message is not received, processing to retransmit the transmitted message to the exchange; And when receiving the A1 interface message required for the connection control from the exchange, generating a response message to the message and transmitting the response message to the exchange.

According to a third aspect of the present invention for achieving the above objects, a method for preventing the loss of A1 interface messages based on User Datagram Protocol / Internet Protocol (UDP / IP) at an exchange includes A1 required for connection control with a base station. Generating an interface message and transmitting the generated message to the base station; and if it is determined that a response message for the transmitted A1 interface message is not received, processing to retransmit the transmitted message to the base station; When receiving the A1 interface message required for the connection control from the base station, characterized in that it comprises the step of generating a response message for the message to the base station.

Hereinafter, the operating principle of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

In the following description, an apparatus and method for providing an A1 interface for preventing a call processing failure in a UDP / IP network in a mobile communication system will be described.

In addition, the base station defined in the following description refers to the meaning including both the base station and the base station controller for controlling the base station.

4 is a diagram illustrating a process of delivering an A1 interface message in a mobile communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 4, assuming that the client 401 first generates an A1 interface message and transmits the generated message to the server 403, the client 401 may generate a sequence number of the message. Set to transmit (410) to the server (403).

Thereafter, the server 403 receiving the message transmits a response message to the client 401 to the client 401, and sets a sequence number of the message in the response message and transmits the message.

When the client 401 generates another A1 interface message and transmits it to the server 403, the client 401 sets and transmits a sequence number to the message.

From here. The method for setting the sequence number of the message may be sequentially increased from 1 for the connection performed by the client 401 or the server 403.

That is, when the client 401 generates the first A1 interface message and transmits it to the server 403, the sequence number of the message is "X" and the sequence number of the second A1 interface message is "X + 1". Becomes

On the contrary, the sequence number of the response message to the sequence number "X" transmitted from the server 403 to the client 401 becomes "X", and the sequence number of the first A1 interface message transmitted from the client 401. Becomes "Y". In addition, the sequence number of the second A1 interface message generated by the server 403 becomes "Y + 1".

FIG. 5 is a diagram illustrating a call processing process through A1 interface connection in a mobile communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the mobile communication system may include a base station 501 and a mobile switch 503, and configure a UDP-based communication network based on a 3GPP2 A.S0012-C specification (February 2005). Define a message to

First, the base station 501 transmits a CM service request message (CM Service_REQ [CONNID, SEQ = 1]) 510 for registration of a network access function to the exchange 503, and the base station 501 transmits the message. The exchange 503 receiving the message sends a response message (Ack [SEQ = 1]) 512 to the base station 501 in response to the CM service request message.

Here, the message transmitted by the base station 501 includes connection authentication information (Connect ID) and a sequence number, and the sequence number is sequentially from 1 for the connection performed by the method (client or server) described with reference to FIG. 4. Can be set by increasing).

In addition, the connection authentication information refers to information for distinguishing the connection setting between the base station 501 and the exchange 503.

Thereafter, the exchange 503 performs a paging process with the receiving base station, and then transmits a radio resource allocation request message (ASSIGN_REQ [SEQ = 1]) 520 to the base station 501.

Here, the message transmitted by the switch 503 to the base station 501 includes a sequence number ([SEQ = 1]) indicating that the message is transmitted for the first time by the switch 503.

Upon receiving the radio resource allocation request message from the exchange 503, the base station 501 retransmits a response message (Ack [SEQ = 1]) 522 to the switch 503.

Subsequently, when the base station 501 completes the resource allocation, the base station 501 transmits a message (ASSIGN_COMP [CONNID, SEQ = 2]) 530 indicating completion of resource allocation to the exchange 503, and receives the message. The exchange 503 sends a response message (Ack [SEQ = 2]) 532 to the base station 501 in response to the message.

Here, the message ASSIGN_COMP indicating the completion of resource allocation transmitted by the base station is a message that is generated and transmitted after transmitting the CM service request message (CM Service_REQ) having a sequence number of "1". The sequence number of the message indicating completion is "2".

Thereafter, the exchange 503 performs a call connection, and then transmits a message (CONNECT [CONNID, SEQ = 2]) 540 indicating the performance of the call connection to the base station 501, and the base station 501. ) Sends a response message (Ack [SEQ = 2]) 542 to the exchange 503 in response to the received message.

After performing the call connection, when a call release request by the user occurs, the base station 501 transmits a call release request message (CLEAR_REQ [CONNID, SEQ = 3]) 550 to the exchange 503. Receive a response message (Ack [SEQ = 3]) 552 to the message from the exchange 503.

Thereafter, the exchange 503 transmits a call release command message (CLEAR_CMD [CONNID, SEQ = 3]) 560 to the base station 501, and the base station 501 receiving the message responds to the message. A message (Ack [SEQ = 3]) 562 is sent to the exchange 503.

Thereafter, the base station 501 which released the call connection transmits a call disconnection completion message (CLEAR_COMP [CONNID, SEQ = 4]) 570 to the exchange 503, and receives the message. Sends a response message (Ack [SEQ = 4] 572) to the base station 501 in response to the message.

6 is a flowchart illustrating a process of performing message retransmission according to a loss of an A1 interface message in a mobile communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 6, when a base station first transmits a message to an exchange, the exchange receiving the message transmits a response message to the base station to the base station.

First, the base station 601 transmits a CM service request message (CM Service_REQ [CONNID, SEQ = 1]) 610 for registration of a network access function to the exchange 603, and from the base station 601 The exchange 603 receiving the message sends a response message (Ack [SEQ = 1]) 612 to the base station 601 in response to the CM service request message.

Thereafter, the exchange 603 transmits a radio resource allocation request message (ASSIGN_REQ [SEQ = 1]) 620 to the base station 601.

If the exchange transmitting the message does not receive a response message for the message from the base station for a predetermined time, the exchange determines that a loss of the response message itself has occurred and performs message retransmission.

In this case, when a response message is lost during normal call processing, the base station may repeatedly receive the same message, and when a message having the same sequence number is received a predetermined number of times to solve the above problem, After discarding the received message, the base station transmits only a response message to the exchange, thereby preventing the call recovery procedure by the UDP timeout.

7 is a diagram illustrating an A1 interface message for supporting a UDP-based A1 interface in a mobile communication system according to an exemplary embodiment of the present invention.

7 (a) illustrates a field added according to the present invention in an existing A1 interface message. The field is delivered in addition to all A1 interface messages defined in the standard.

Referring to FIG. 7 (a), the A1 interface message according to the present invention is based on all A1 interface messages defined in the standard, and a sequence number field (SEQ NUMBER) including information indicating that the message is a specific message. 713.

Figure 7 (b) shows the added field in the standard format.

Referring to FIG. 7B, an A1 version 701 indicates a version of an A1 interface message presented in the present invention. The compatibility of the A1 interface message may be determined based on the version.

A connection type 703 indicates a detailed item of connection setting to be performed by the A1 interface message.

Destination Local Reference (705) is the key of the destination that can distinguish the call between the communication counterpart, base station and exchange and is always included in every message so that the controller and exchange can make each call. Use as a distinguishable destination separator.

A source local reference 707 is a key of a source that can distinguish a call between a communication counterpart, that is, a base station and an exchange, and is always included in every message so that the base station and the exchange each can be used. It is used as a source delimiter to distinguish a call.

A source IP address 709 is an IP address for distinguishing each base station. Together with the source local reference 707, the call may be used as a delimiter for distinguishing a call.

A retransmit number 711 is a field for retransmission in case of a loss of the UDP / IP based A1 interface message of the present invention and is a field for recording the number of transmissions when multiple transmissions are performed for the same message. If it is the first message transmission, it is set as 0x00. If it is retransmitted due to transmission failure, it is increased by one.

The sequence number 713 refers to a field for retransmission in case of loss of the UDP / IP based A1 interface message of the present invention.

All fields including the sequence number 713 must be added to the A1 interface message as indicated in FIG. 7 (a). M represents a required element.

8 is a diagram illustrating a process of processing a network failure in a mobile communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 8, a failure of a network may be identified using a message transmitted between the base station 805 and the exchange 801.

Here, the message for confirming the failure of the network will be described in detail with reference to FIG. 9.

First, the base station 805 and the exchange 801 periodically transmit the message.

When the base station 805 determines that a failure occurs between the switch 801, the base station 805 changes the routing path to another switch 803, thereby performing continuous call processing.

9 is a diagram illustrating an A1 interface message for identifying a system state and a system routing path in a mobile communication system according to an exemplary embodiment of the present invention.

The message is a message for confirming whether a network is connected between the base station and the exchange. In the mobile communication system, periodic message transmission may be performed to determine a failure of the network.

9 (a) shows a network system confirmation message for identifying the network failure.

Referring to FIG. 9A, the message includes an A1 version 901, a connection type 903, a destination local reference 905, and a destination local reference. A source local reference (907), a source IP address (909), a retransmit number (911), and a sequence number (SEQ NUMBER) 913 are included.

Here, the connection type 903 may include information indicating normal call connection (Inactivity Test) and information indicating that it is a response message (Inactivity Test Ack).

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, by using the response message to the message generated in the A1 interface section of the mobile communication system according to the present invention, it is possible to increase the reliability of the transmission and reception of the message used in the existing mobile communication system.

In addition, in the mobile communication system according to the present invention, by periodically transmitting a message confirming the system state, by performing a call switch when a failure occurs, it is possible to provide a continuous call connection.

Claims

A mobile communication system for preventing the loss of A-one interface messages,

UDP / IP is used as a data link layer protocol for connection with a mobile switching center (MSC), and when an A1 interface message for connection control is received from the exchange, a response message for the message is transmitted to the exchange. A base station controller (BSC)

The switch uses the UDP / IP as a data link layer protocol for connection with the controller and, when receiving an A1 interface message for connection control from the controller, transmits a response message to the controller to the controller. Mobile communication system, characterized in that.

The method of claim 1,

The mobile communication system for preventing the loss of the A-one interface message,

When confirming the call connection, the mobile communication system characterized in that for identifying the failure of the system using the A1 interface message to identify the system failure.

The method of claim 2,

And transmitting the A1 interface message to the receiving side after transmitting the A1 interface message to the receiving side and not receiving a response message for the message from the receiving side.

The method of claim 1,

The A1 interface message for the connection control,

And a field for setting a sequence number of the A1 interface message to prevent the loss of the A1 interface message.

The method of claim 4, wherein

The A1 interface message for the connection control,

And a sequence number sequentially increased according to a process performed by the controller or the base station.

The method of claim 3, wherein

The A1 interface message for identifying the system failure,

A mobile communication system, characterized in that it may include information indicating the normal call connection (Inactivity Test).

The method of claim 6,

When receiving the A1 interface message including the information indicating the normal call connection (Inactivity Test), it is possible to transmit a response message including the information (Inactivity Test Ack) indicating that the response to the information Communication system.

In the method for preventing the loss of A1 interface message based on UDP / IP (User Datagram Protocol / Internet Protocol) in the base station,

Generating an A1 interface message necessary for connection control with the exchange and transmitting the generated message to the exchange;

If it is determined that a response message for the transmitted A1 interface message is not received, processing the transmitted message to be retransmitted to the exchange;

When receiving the A1 interface message required for the connection control from the exchange, generating a response message to the message and transmitting the message to the exchange.

A method for preventing the loss of A1 interface messages based on UDP / IP (User Datagram Protocol / Internet Protocol) in an exchange,

Generating an A1 interface message required for connection control with a base station and transmitting the generated message to the base station;

If it is determined that a response message to the transmitted A1 interface message is not received, processing to retransmit the transmitted message to the base station;

When receiving the A1 interface message required for the connection control from the base station, generating a response message to the message and transmitting the message to the base station.

The method according to claim 8 or 9,

The base station and the switch further comprises the step of confirming the failure of the system using an A1 interface message for identifying a system failure after the call connection.

The method of claim 10,

The A1 interface message for the connection control,

The method of claim 11,

The A1 interface message for the connection control,

The method of claim 10,

The A1 interface message for identifying the system failure,

The method may include information indicating normal call connection (Inactivity Test).

The method of claim 13,

When the base station and the exchange receive the A1 interface message including the information indicating the normal call connection (Inactivity Test), the base station and the exchange transmits a response message including the information indicating the response message (Inactivity Test Ack) for the information How it can be.