KR100512359B1 - apparatus and method for message conversion of inter different mobile communication system - Google Patents

Abstract

The present invention is a mobile communication system, in particular, when different systems are installed according to the service characteristics provided to the terminal, different mobile communication to enable the soft handoff of the terminal between different systems by converting messages between different systems An apparatus and method for message conversion between systems.

Message conversion apparatus between different mobile communication systems according to the present invention, in a mobile communication system consisting of a lower system and a higher generation system, the payload by analyzing the AAL 5 message transmitted from the upper system in the message switching between different systems First message converting means for copying the detected payload data and transmitting the detected payload data to the sub-system as an A7 message; After analyzing the A7 message from the subsystem, calculate the VPI / VCI of AAL 5 mapped to the destination address, detect the actual data, attach the AAL 5 header including the VPI / VCI, and use the actual data as payload. And second message converting means for sending the ATM cell.

Description

Apparatus and method for message conversion of inter different mobile communication system}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for converting a data format between systems in a handoff between a lower system (e.g., 2G system) and a higher system (e.g., 3G system). The present invention relates to a format conversion method between A7, which is a signaling format, and AAL5, which is a signaling format of a 3G system.

Currently, mobile communication systems have evolved from existing voice-oriented second generation services to voice and data-oriented third generation systems. Unlike the second generation, the third generation system adopts ATM (Asynchronous Transfer Mode) method, unlike the existing circuit type, because the ratio of data service is increased. Therefore, existing service providers must replace all existing 2G systems with 3G systems to provide new 3G services. However, replacing all of the nationwide systems would be a significant burden in terms of time and cost, and would like to provide third generation services using existing second generation system equipment.

For this purpose, compatibility between existing second generation equipment and newly installed third generation equipment is important, for example, transferring data from a second generation base station controller (BSC) to a third generation control station (BSC), or vice versa. Handoffs such as data transfer from the generation control station to the second generation control station should be possible. However, because the data formats are different, you need to convert the format in the middle. The important thing to do here is to have a minimum delay in message conversion, a minimum delay in data and no loss of data.

On the other hand, the mobile communication system of the code division multiple access method has been developed from the second generation system standards such as the IS-95 standard which focuses on the transmission / reception of voice signals, and the IMT-2000 standard which can transmit not only voice but also high speed and high speed data. It is progressing with 3rd generation system like this.

Since the handoff between the second generation system and the third generation system is not defined in the standard specification, a method for providing a seamless service between the third generation system and the second generation system being serviced should be provided.

In recent years, soft handoff between switching systems using routers has been implemented and provided similarly to soft handoff between control stations. That is, the router performs an operation of routing signaling messages, traffic messages, etc. to the destination processor of the counterpart system in the soft handoff between the switching systems corresponding to the soft handoff.

However, as mentioned above, the handoff between the 2nd generation system and the 3rd generation system is not defined in the standard specification, and since the 2nd generation system and the 3rd generation system have different backbone networks, different generations are used by using the current router. Cannot implement cross-system soft handoff.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides an apparatus and method for converting messages between different mobile communication systems, which can convert AAL messages of ATM-based higher systems into messages of lower systems. There is a purpose.

The present invention provides an apparatus and method for converting messages between different mobile communication systems to convert an AAL 5 message of a higher system into an A7 message of a lower system and to convert an A7 message of a lower system to an AAL 5 message of a higher system. The purpose is to provide.

Message conversion device between different mobile communication systems according to the present invention for achieving the above object, in the message conversion between different systems in a mobile communication system consisting of a lower system and a higher generation system,

First message converting means for analyzing the payload start and end by analyzing the AAL 5 message transmitted from the upper system, and copying the detected payload data to the lower system as an A7 message;

After analyzing the A7 message from the subsystem, calculate the VPI / VCI of AAL 5 mapped to the destination address, detect the actual data, attach the AAL 5 header including the VPI / VCI, and use the actual data as payload. And second message converting means for sending the ATM cell.

Preferably, the first message converting means detects the start of the payload when the AAL 5 message including the A7 signaling format is included in the payload, detects the end of the payload as the length information of the trailer, and takes only the actual payload. A processing unit; And a message copying unit which copies the payload processed by the IPC header processing unit and transmits the payload to the subsystem as an A7 message.

Preferably, the second message converting means calculates a destination address in the A7 signaling message transmitted from the sub-system and the cam unit mapping the addresses of the sub-system and the super-system using the VPI / VCI of AAL 5 using the cam unit, A packet identifier detection unit for distinguishing a desired packet identifier and detecting actual data, and a message copy unit for attaching a header including the VPI / VCI and inserting the next A7 packet into a payload part to make an ATM cell. .

Preferably, the IPC header processing unit and the packet identifier detecting unit detect the start of the payload of AAL 5 and the start of data of the A7 message by using counters, respectively.

Preferably, the packet identifier detection unit reads the packet identifier of the A7 message, distinguishes the A7 / A3 message, and detects only the A7 message.

In the message conversion method between different mobile communication systems according to the present invention, in a mobile communication system composed of a lower system and a higher generation system, a message switching method between different systems,

Counting and removing a start and end of a payload from the header and trailer of the AAL 5 when the input message is AAL 5; A first message conversion step of copying the payload and transmitting the A7 message to the subsystem;

Calculating a VPI / VCI using a cam unit as a destination address included in header information of the A7 message if the input message is A7; Classifying a message type using a packet identifier of an A7 message; Detecting data using the length information of the header of the A7 message and the counter; And a second message conversion step including inserting the header including the calculated VPI / VCI and the next incoming A7 message packet into the payload part to make an ATM cell and transmitting the same.

Hereinafter, with reference to the accompanying drawings as follows.

1 is a block diagram showing a message conversion apparatus between different systems using a gateway according to an embodiment of the present invention.

Higher system (2G) 100 comprising a plurality of base station control stations 101 and a plurality of base stations 104 and CCINU 101 and MCINU 102 that match and manage the control stations 101 in a network. and;

Higher system 3G including a plurality of base station control stations 113 and a plurality of base stations 104, a CAN 111 for matching and managing the control station 113, and a MAN 112 for matching CAN. 110; A mobile switching system (MSC) 120 and a gateway (GW) 130 for converting messages transmitted / received between the lower system 100 and the upper system 110.

The gateway 130 is connected between the CCINU 101 of the lower system 100 and the CAN 111 of the upper system and to the MAN 112 of the CCINU 101 and the upper system, thereby providing the lower and upper systems 100 and 110. It converts the A7 format, the signaling message of the call control processor (CCP), into a format suitable for each other.

2 is a detailed block diagram of a gateway system according to the present invention.

The driver interface 220 for interfacing the message with the host system 210, the multiplexer 230 for detecting the header information of the AAL5 message transmitted from the driver interface 220, and the first-in first-out memory 240 for transmitting and receiving ATM cells. And an AAL5 segmentation and reassembly sublayer (SAR) unit 250 for decomposing an AAL5 message into an ATM cell and combining the A7 message into an ATM cell, and a memory unit (DPRAM) for storing messages inputted and outputted from the AAL5 SAR unit 250 ( 260 and a message conversion unit 270 for converting messages between the upper system 210 and the lower system 280.

The message converter 270 processes an IPC header of data stored in the first DPRAM 261 to detect a payload only by converting a message of a higher system message into a lower system message, and the processing A first message converter comprising a message copying unit 272 for copying the header information to the lower generation system by copying the header information into actual data;

When the lower system message A7 is converted into the upper system message AAL 5, the packet identifier detection unit 273 which detects the packet identifier ID of the message transmitted to the lower system and distinguishes whether it is A3 / A7; The second CAM unit 275 for obtaining the VPI / VCI with the destination address of the packet determined by the packet identifier detection unit A7 and the actual data is copied, the header is attached, converted into an AAL 5 message, and transferred to the second DPRAM 262. It consists of a second message conversion unit composed of a message copying unit 274.

An apparatus and method for converting messages between different systems according to an exemplary embodiment of the present invention as described above will be described with reference to the accompanying drawings.

First, the gateway (GW) 130 is configured as a separate hardware system between the lower system 100 and the upper system 110 to provide soft handoff between the control stations 103.

The gateway 130 converts the AAL5 message of the upper system 110 into the A7 message of the lower system, and converts the A7 message of the lower system 100 into the AAL5 message of the upper system.

Here, in the mobile communication system, a message can be largely divided into a signaling message and a traffic message. The signaling message is composed of AAL5 in the 3G system, and the signaling message is called A7, and the traffic message is composed of AAL2. It is called.

Here, the AAL 5 message is composed of AAL 5 header information, a payload (AAL PDU) including a IPC header, a pad and a trailer (Pad / trailer) as shown in FIG. Header information of AAL 5 includes GFC (generic flow control), VPI / VCI, PT (payload type) / CLP (cell loss priority) / HEC (header error control), etc. IPC header information includes a destination address and a packet identifier. (Pkt ID), length information of actual data DATA, and the like.

The GFC controls traffic flow to mitigate short-term overload conditions, VPI / VCI is a routing bit, PT is a payload type, CLP defines cell loss priority, and HEC is a cell Used in the physical layer for bit rare detection and modification of headers.

The A7 message is composed of IPC header information and data as shown in FIG. 4, and the IPC header information includes a destination address (4 bytes), a packet identifier (1 byte), and data length information (LEN, 1 byte). .

The message conversion in the gateway will be described with reference to FIG. 2 as follows. First, an operation of converting a message of the upper system 210 into a message of the lower generation system 280 is as follows.

Since the data transmitted to the upper system 210 is an ATM cell, the ATM cells are reassembled to AAL 5. To this end, the AAL5 message transmitted from the upper system 210 is input to the first multiplexer (MUX) 231 of the multiplexer 230 through the driver interface 220. The first multiplexer 231 reads the header information of AAL5 to determine whether it is an A3 message or an A7 message.

If the A7 message related to the present invention corresponds to the AAL 5 format, the A7 message is transmitted to the AAL5 SAR unit 250 as the ATM cell size (for example, 53 bytes) through the first queue 241 of the first-in-first-out memory 240. The AAL 5 SAR here is generally a sublayer of the Asynchronous Adaptation Layer (ATM) adaptation layer, which provides the function of decomposing user information into ATM cells and assembling the received ATM cells into user information.

The receiving end RX 251 of the AAL 5 SAR unit 250 recombines the AAL 5 messages and stores the AAL 5 message in the first DPRAM 261 of the memory unit 260.

 The message converter 260 converts the AAL 5 message into an A7 message by the IPC header processor 271 and the message copyer 272, and delivers the AAL 5 message to the subsystem 280.

Since the AAL 5 message (AAL5 Cell) carries the A7 signaling format information in the payload as shown in FIG. 3, only the header and trailer of AAL 5 need to be removed and then transmitted to the subsystem. The IPC header processing unit 271 has an internal When the AAL 5 message is input using the counter, the count starts and the beginning of the actual payload is detected. The length of the trailer is used to detect the end of the payload.

In addition, the payload may be copied from the message copying unit 272, attached with an IPC header, and transmitted to the subsystem 280 in the A7 message of FIG.

On the other hand, the operation of converting the message of the subsystem 280 to the message of the lower generation system 210 is as follows.

The message converter 270 is composed of a packet ID detector 273, a cam unit 275, and a message copy unit 274 to convert an A7 message transmitted to a subsystem into an AAL 5 cell, and the packet ID detector 273 includes: In the IPC header information of the A7 message, when the destination address is inserted into the cam portion 275, the A7 address and the AAL5 address are mapped to the cam portion 275 correspondingly, so that the VPI / VCI of AAL 5 is calculated. That is, the cam part 275 has the A7 address and AAL 5 address which are used, mapping each other.

The next packet identifier (Pkt ID) coming from the A7 message is read to check whether it is 0x20 or 0xA0. The packet identifier distinguishes whether the packet is A7 or A3. In the case of A3, the packet identifier is 0x00, and in the case of A7, 0x20 or 0xA0. Since only the conversion for A7 is described here, the description of A3 is omitted.

If the packet identifier is not one of the three types (0x00, 0x20, 0xA0), the packet which has been processed as an error is discarded.

The length information (Len, 1 byte) coming next in the A7 message is the length information of the actual data, so that the length information can be read to accurately detect the data. To this end, the packet identifier detector 273 has a counter therein to accurately detect the beginning of the actual data.

The message copy unit 274 attaches the header information including the calculated VPI / VCI, inserts the incoming A7 packet into the payload portion as it is, and attaches the trailer at the end.

The AAL 5 message converted by the message copying unit 274 of the message converting unit is divided into ATM cells at the transmitting end of the SAR of AAL 5 through the second DPRAM 262 of the memory unit 260, and then queues and multiplexers of the first-in-first-out memory. It is sent to the host system through the driver interface.

Referring to FIG. 3, the AAL5 signaling message format includes a packet data unit that is AAL 5 header information and payload data, and has pad structure and a trailer inserted at the end of the message.

Since the payload data includes the IPC header information, it is possible to convert only to the actual payload data portion and remove the rest of the payload data into an A7 message. Therefore, it is possible to detect the start of payload using the counter, detect the last part of the payload using the length information of the trailer, and deliver the A7 message which takes only actual payload data to the subsystem.

On the contrary, the format conversion for converting the A7 signaling message into the AAL5 signaling message is shown in FIG. 4.

Since the header of the A7 signaling message includes a destination address, packet identifier, and length information, the packet identifier detection unit calculates the VPI / VCI using the cam unit 175 using the destination address to generate a header of AAL 5. Copy and paste the IPC header and data of the A7 signaling message. Finally, a pad / trailer is added to the end of the ALL5 signaling message to create an AAL 5 signaling message.

As described above, the apparatus and method for message conversion between different mobile communication systems according to the present invention enables mutual data exchange between the existing 2nd generation system and the 3rd generation system. Handoff is possible between systems. Therefore, it is possible to perform handoff with the new 3rd generation equipment through the slight upgrade of the existing 2nd generation equipment, so that the entire 3rd generation service is available at a low cost.

1 is a configuration diagram of connection between different mobile communication systems according to an embodiment of the present invention.

2 is a block diagram showing a message conversion device between different mobile communication systems according to an embodiment of the present invention.

3 illustrates an example of converting a message of AAL5 into an A7 message according to an embodiment of the present invention.

4 is a diagram illustrating a format conversion of an A7 message into an AAL 5 message according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100,280 ... subsystem (3G) 110,210 ... parent system

230 ... multiplexer 240 ... first in, first out memory

250 ... AAL5 SAR section 260 ... Memory

270 ... message converter 271 ... IPC header processor

272,274 Message copy unit 273 Packet ID detection unit

275 ... CAM part

Claims (6)

In the message switching between different systems using a gateway in a mobile communication system composed of a lower system and a higher system, A driver interface for interfacing a message with the host system; A multiplexer for detecting header information of an AAL5 message transmitted from the driver interface; An AAL5 SAR unit for decomposing the AAL5 message into an ATM cell and combining the A7 message into an ATM cell; Message conversion unit for converting messages between the upper system and the lower system is included, The message conversion unit, An IPC header processing unit which detects the start of the payload, detects the end of the payload as length information of the trailer, and takes only the actual payload when an AAL 5 message including the A7 signaling format is input to the payload; First message converting means including a message copying unit which copies the payload processed by the IPC header processing unit and transmits the payload to the subsystem as an A7 message; In the A7 signaling message transmitted from the lower system and the upper system and the cam unit mapping the address, the destination address is calculated using the cam unit using the VPI / VCI of AAL 5 and the actual packet data And a second message converting means including a packet identifier detecting unit for detecting, and a message copying unit including a header including the VPI / VCI, and inserting a next A7 packet into a payload part to make an ATM cell. Message conversion device between different mobile communication systems. delete delete The method of claim 1, And the IPC header processing unit and the packet identifier detecting unit detect the start of the payload of AAL 5 and the start of the data of the A7 message by using counters, respectively. The method of claim 1, The packet identifier detecting unit reads the packet identifier of the A7 message, classifies the A7 / A3 message, and detects only the A7 message. In the message switching between different systems using a gateway in a mobile communication system composed of a lower system and a higher generation system, Counting and removing the start and end of the payload from the header and trailer of the AAL 5 if the input message is AAL 5; A first message converting step of copying the payload, converting the AAL 5 into an A7 message, and transmitting the converted AAL 5 message to a subsystem; Calculating a VPI / VCI using a cam unit as a destination address included in header information of the A7 message if the input message is A7; Classifying a message type using a packet identifier of the A7 message; Detecting data using the length information of the header of the A7 message and the counter; And a second message converting step including inserting the header including the calculated VPI / VCI and the next incoming A7 message packet into the payload part to form an ATM cell and transmitting the same to an upper system. How to convert messages between different mobile communication systems.