KR20030072447A - Apparatus for processing asynchronous transfer mode cells in an asynchronous node b system - Google Patents

Abstract

The present invention relates to an ATM cell processing apparatus of an asynchronous transmission mode (ATM) base station system, comprising: an upper self link unit providing a cable communication link with an external upper self and a lower device supporting ATM backplane communication with a lower device; A link unit, a control unit for providing a system clock and a cell bus clock in the channel card unit, controlling state management and downloading functions of lower devices, and converting the types of ATM cells transmitted through the upper self link unit from AAL2 to AAL5; An AAL type conversion unit for transmitting through the lower device link unit, an interface unit for implementing an interface between masters in an interface between the lower device link unit and the control unit and an interface between the upper self link unit and the control unit, and a cell bus in the channel card unit Utopia Level Specification of ATM Cells Transmitted through It includes a level conversion unit that provides an interface between the upper self link unit and the interface unit and the lower device link unit and the interface unit having different pia level specifications, and uses the ATM forum Utopia Level 2 specification and converts the AAL2 cell into an AAL5 cell. By simultaneously processing the AAL2 cell and the AAL5 cell, it is possible to secure communication bandwidth for voice, video and data communication.

Description

Asynchronous transmission mode cell processing unit of an asynchronous base station system {APPARATUS FOR PROCESSING ASYNCHRONOUS TRANSFER MODE CELLS IN AN ASYNCHRONOUS NODE B SYSTEM}

The present invention relates to a controller for controlling a base station in an IMT-2000 system based on an asynchronous transfer mode (ATM), and in particular, converts an ATM Adaptation Layer (AAL) type of an ATM cell. The present invention relates to an ATM cell processing apparatus of an asynchronous base station system capable of efficiently operating a communication bandwidth in data transmission.

As is well known, as technology development of mobile communication systems is advanced, various public and private mobile communication services such as vehicles, individuals, the public, data, and messaging using wireless access technologies such as cellular, cordless, and satellite are provided.

This is often categorized into generations: first generation is analog cellular, second generation is digital cellular, and third generation is Futuristic Public Land Mobile Telecommunication Systems (IMT-2000).

1 is a configuration diagram of an air interface of an IMT-2000 system based on ATM.

As shown in the figure, the IMT-2000 system includes a plurality of RNSs (Radio Network System) 2 connected to the core network 1 through the Iu interface.

RNS (2) is composed of a Radio Network Controller (RNC) 100 and one or more Node B (200), each Node B (200) manages one or more cells, RNC (100) through the Iub interface Connected with

The RNC 100 performs a connection / separation function during handover between the Node Bs 200, and the RNC 100 also performs a connection / separation function in the case of an inter-cell handover within the same Node B 200.

The connection between the RNC 100 is made through Iur, where Iur and Iu are interfaces that logically connect each system.

FIG. 2 is a block diagram of Node B shown in FIG. 1.

As shown in the drawing, the Node B includes an RFU (Radio Frequency Unit) 210, an APC (Analog Processing Card) 221, a plurality of CHCs (222/1 to 222 / n), and a CPC A Channel Card Unit (CHU) 220 consisting of a Channel Card Peripheral Processor Card (223), an RNC Interface Unit (RIU) 230 performing an interface with a Radio Network Controller (RNC) and a routing function in a Node B, and a Node B unit. Base station main processor unit with built-in BS Synchronization Unit (BSU) 240 and Base Station Main Processor Card (BMC) 251 to generate system clocks and provide a reference clock for synchronizing the clocks used in each unit 250).

The APC 221 converts an analog signal into a digital signal when transmitting and converts a digital signal into an analog signal when receiving.

CHCs 222/1 to 222 / n include a plurality of modem chips (not shown), and a plurality of channel elements (not shown) are disposed on each modem chip.

The CPC 223 performs a function of controlling the CHCs 222/1 to 222 / n.

The BMC 251 performs a function of allocating and managing channel elements to the CHCs 222/1 to 222 / n through the CPC 223.

On the other hand, the IMT-2000 system as described above implements the internal network as a high-speed ATM network to efficiently operate the communication bandwidth in the transmission of voice and video data, in the ATM network all the various communication information fixed length of a predetermined byte The data is divided into data, and destination identification information called a header is given thereto. This header attachment information is called a cell, and information is transmitted by sequentially sending this information over a line.

As described above, since all information is transmitted in units of cells in the ATM network, a part related to cell transmission is not processed separately in consideration of a transmission medium or service such as voice, data, and video.

However, the quality of service (delay time, error rate, etc.) required for each service is different, and it is necessary to absorb the difference in quality conditions for ATM cellization of the original information of each service, and processing this function is AAL. to be.

The AAL types include AAL1, AAL2, and AAL5. First, in the case of AAL1, data refers to a service for video and audio signals that require real time and are always processed at the same bit rate. In the case of AAL2, data refers to a service for video and audio signals that require real time and are processed at varying bit rates (variables). In the case of AAL5, data refers to a service in which data is non-real time and bit rate is processed in a variable manner.

In addition, CHU of IMT-2000 base station system based on ATM uses AAL5 cell as signal for operation and control, and real voice and video data adopts AAL2 cell as communication protocol, which makes it possible to transmit voice and video data efficiently. Let it go.

Here, since the AAL2 cell transmits a channel having high speed and real time, a constant and sufficient communication bandwidth must be secured.

However, although systems for processing AAL5 cells have been commercialized, systems for processing AAL2 cells have recently been introduced, which requires an effective and optimized system approach, which has emerged as a new demand.

The present invention is a result of the research and development to solve the above-mentioned conventional requirements, the UTOPIA level 2 standard of the ATM Forum in the ATM-based asynchronous base station system It is an object of the present invention to provide an ATM cell processing apparatus capable of efficiently operating communication bandwidth in data transmission by converting an AAL2 cell into an AAL5 cell and simultaneously processing the AAL2 cell and the AAL5 cell.

In order to achieve the above object, the present invention provides an asynchronous transmission mode cell processing apparatus mounted on a CHU self of an ATM-based base station system and managing a peripheral card. The upper self link unit providing the communication link, the lower device link unit supporting ATM backplane communication with the lower device, the system clock and the cell bus clock in the CHU, and the state management and downloading functions of the lower devices. A control unit for controlling, an AAL type conversion unit for converting the types of ATM cells transmitted through the upper self link unit from AAL2 to AAL5 and transmitting through the lower device link unit, an interface between the lower device link unit and the control unit; Between masters in an interface between the upper self link unit and the control unit An interface unit for implementing an interface of the upper self link unit, the interface unit, the lower device link unit, and the Utopia level standard having different Utopia level standards by converting the Utopia level standard of ATM cells transmitted through the cell bus in the CHU. And a level converting unit providing an interface between the interface units.

1 is a configuration diagram of an air interface of an IMT-2000 system based on ATM;

FIG. 2 is a block diagram of Node B shown in FIG. 1;

3 is a block diagram of a CPC shown in FIG. 2 in which an ATM cell processing apparatus according to the present invention is implemented;

4 is an interface diagram of an asynchronous transmission mode cell processing apparatus according to the present invention;

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

223: CPC 310: upper self link unit

320, 325: level converter 330: AAL type converter

340: lower device link unit 350, 355: interface unit

360: control unit

There may be a plurality of embodiments of the present invention, hereinafter with reference to the accompanying drawings will be described in detail a preferred embodiment. Through this embodiment, it is possible to better understand the objects, features and advantages of the present invention.

3 is a block diagram of a CPC (Channel Card Peripheral Processor Card) shown in FIG. 2 in which an ATM cell processing apparatus according to the present invention is implemented.

The CPC 223 is a processor board mounted on the CHU self and manages peripheral cards APC and CHCs. The CPC 223 matches AAL2 and AAL5 with an external system.

The upper self link unit 310 is a device that provides a low voltage differential signaling (LVDS) link with an external upper self, thereby performing ATM cable communication with the upper self.

The first and second level converters 320 and 325 convert an utopian level specification of ATM cells transmitted through a cell bus to provide an interface between utopian level 1 and utopian level 2.

The AAL type converter 330 converts the types of ATM cells transmitted through the cell bus from AAL2 to AAL5 to ensure sufficient bandwidth for AAL2 cell processing.

The lower device link unit 340 supports ATM backplane communication with lower devices such as CHC.

The first and second interface units 350 and 355 may implement an interface between masters in an interface between the lower device link unit 340 and the controller 360 and an interface between the upper self link unit 310 and the controller 360. It plays the role of slab-to-slab.

The controller 360 provides a system clock and a cell bus clock in the CHU, and controls state management and downloading functions of lower devices.

4 is an interface configuration diagram of an ATM cell processing apparatus according to the present invention, and shows detailed configurations of the first and second level converters 320 and 325, and illustrates the input / output relationship between utopian interface signals standardized in the ATM forum. In the figure, "AAL2 / 5 Converter" of the Utopia Level 1 standard refers to the AAL type converter 330, and "AAL FPGA" refers to the first and second interface units 350 and 355.

The first and second level converters 320 and 325 are composed of a plurality of demuxes, a plurality of level 2 converters and decoders, and a utopian level specification of ATM cells transmitted through a cell bus according to an output signal of a decoder based on address information. Provides an interface with Utopia Level 1 and Utopia Level 2 by converting them.

In the utopia interface, transmission (Tx) and reception (Rx) directions are determined based on the flow direction of data centering on the ATM layer, and data is transmitted and received in synchronization with the transmission clock and the reception clock provided by the ATM layer. Referring to the Utopia interface signals shown in the figure, TxCLK is a transmit clock, RxCLK is a receive clock, TxData is a transmit data, RxData is a receive data, TxEnb is a transmit data enable signal, RxEnb is a receive data enable signal, and TxCAV is a cell data. The signal for requesting to start transmission of RxCAV is a cell available signal indicating that there is a cell to be transmitted, and TxSOC is a signal indicating the start of cell data.

Hereinafter, a process of transmitting and converting an ATM cell by the ATM cell processing apparatus according to the present invention configured as described above will be described.

First, the AAL2 cell and the AAL5 cell are transmitted to the first level converter 320 through the upper self link unit 310 in the upper self. At this time, the AAL2 cell and the AAL5 cell are transmitted to the Utopia Level 2 standard through the same cell bus.

Then, the first level converter 320 physically divides the AAL2 and AAL5 cells and transfers the AAL2 cells to the AAL type conversion unit 330 according to the Utopia Level 1 standard, and the AAL5 cells are the Utopia Level 1 standard. Forward to 355.

Next, the AAL type converter 330 converts the input AAL2 cell into the AAL5 type and transfers the AAL2 cell to the second level converter 325 in the utopia level 1 standard.

Accordingly, the second level converter 325 receives the AAL5 cell and transfers it to the lower device such as CHC through the lower device link unit 340 in the Utopia level 2 standard.

In addition, the AAL5 cell delivered to the second interface unit 355 is delivered to the control unit 360 in the Utopia Level 1 standard and used for the operation and management of the CHU system.

Meanwhile, the controller 360 transmits the AAL5 cell to the first interface unit 350 according to the utopia level 1 standard for controlling the lower device, and the first interface unit 350 transmits the AAL5 cell to the utopia level 1 standard. Transfer to the two-level conversion unit 325.

Then, the second level converter 325 receives the AAL5 cell and delivers it to the lower device such as CHC through the lower device link unit 340 in the Utopia level 2 standard.

According to the present invention, a commercial device can be used at design time by separating the AAL types of ATM cells into Utopia level 2 addresses, and the AAL2 cells are completely hardware converted to AAL5 cells and transferred to the CHC. In order to ensure sufficient bandwidth of the CHU system, the processing of AAL2 cells in the CHU system can be handled by only one CPC, so that many CHCs can use commercial AAL5 processing devices.

As described above, the present invention utilizes the Utopia Level 2 standard of the ATM Forum and converts an AAL2 cell into an AAL5 cell to simultaneously process an AAL2 cell and an AAL5 cell, thereby securing communication bandwidth for voice, video, and data communication. There is.

Claims (2)

An ATM cell processing apparatus mounted on a channel card unit (CHU) self of a base station system based on an asynchronous transmission mode (ATM) and implemented on a processor board managing a peripheral card, An upper self link unit for providing a cable communication link with an external upper self; A lower device link unit supporting ATM backplane communication with the lower device; A control unit providing a system clock and a cell bus clock in the CHU and controlling state management and downloading functions of the lower devices; An AAL type conversion unit for converting types of ATM cells transmitted through the upper self link unit from AAL2 to AAL5 and transmitting them through the lower device link unit; An interface unit for implementing an interface between masters in an interface between the lower device link unit and the controller and an interface between the upper self link unit and the controller; And A level for converting a utopian level specification of ATM cells transmitted through a cell bus in the CHU to provide an interface between the upper self link unit and the interface unit and the lower device link unit and the interface unit having different utopian level standards. An asynchronous transmission mode cell processing apparatus of an asynchronous base station system including a conversion unit. The method of claim 1, And the level converting unit converts a utopia level standard based on address information of the ATM cells.