KR100359914B1 - Device for converting of aal5 atm cell to aal2 atm cell - Google Patents

Abstract

The present invention relates to an apparatus for converting an ATM Adaptation Layer (ATL) 5 ATM cell mounted in an International Mobile Telecommunication (IMT) -2000 base station controller based on an Asynchronous Transfer Mode (ATM) to an ATM2 ATM cell, and more particularly, voice data. The present invention relates to an apparatus for firstly distinguishing an AAL5 cell from an AAL5 cell carrying non-voice data, and then converting an AAL5 ATM cell into an AAL2 ATM cell, which converts an AAL5 cell carrying voice data into an AAL type 2 ATM cell. According to the apparatus for converting an AAL5 ATM cell into an AAL2 ATM cell according to the present invention, AAL2 instead of AAL1 is adopted when sending voice data to an ATM cell, thereby maximizing the efficiency of BandWeed, which is an AAL2 advantage, and simultaneously using an AAL2 type cell. Has the effect of making it applicable to ATM switches.

Description

DEVICE FOR CONVERTING OF AAL5 ATM CELL TO AAL2 ATM CELL}

The present invention is based on ATM (International Mobile Telecommunication; IMT) -2000 base station controller mounted on ATM (ATM) Adaptation Layer (ALA). 5 Asynchronous Transfer Mode (ATM) ATM ".) The present invention relates to an apparatus for converting a cell into an AL2 ATM cell. More specifically, an AAL5 cell containing voice data and an AAL5 cell containing non-voice data are first distinguished. The present invention relates to an apparatus for converting an AL5 ATM cell that converts a cell into an AAL type 2 ATM cell form into an AL2 ATM cell.

As is well known, technology for carrying voice data in an ATM cell is widely known at present, and this is called Voice Telephony Over ATM (VTOA) in the ATM Forum. At this time, ATM cell type uses AAL type 1 as defined in International Telecommunication Union Standardization Sector (ITU-T) Recommendation I.363.1 standard.

However, the AAL type 1 ATM cell described above must always transmit at the same bit rate, and additionally, BandWidth is inevitable to reduce the inter-voice delay, and the voice signal is 64 Kbps or 64 Kbps. It has to be determined as a multiple of 64K × N, that bandweed continues to be used even though there is no voice signal, and that it cannot process compressed voice signals or silence.

Overcoming these shortcomings is in the form of AAL type 2 ATM cells, the standard of which is defined in ITU-T Rec. I.363.2. Attempts to transmit voice to these AAL2s are increasing. The advantages of AAL2 are that it can send variable voice data and put multiple users together in one ATM cell. As a result, you can use Bandweed efficiently.

However, when the AAL2 ATM cell is adopted according to the above description, there is a problem that is not applicable to the ATM switch in the conventional IMT-2000 base station controller. This is because the conventional ATM switch is capable of switching the AAL5 ATM cell format, but the AAL2 ATM cell is not capable of switching.

Accordingly, the conventional ATM switch in the IMT-2000 base station controller uses an AAL type 1 ATM cell type when transmitting a constant bit rate (CBR) through an ATM network. In other words, AAL type 1 was used in the form of a person carrying voice data. At this time, according to VTOA, to operate ATM network by adopting AAL1, peak cell rate (PCR), cell loss ratio (CLR), and cell delay variation (CDV) are added. As a result, there is data necessary, and thus additional bandweeds are required, and even though there is no traffic, the operational data is continuously transmitted, thereby reducing the efficiency of bandweeds.

Due to this, there is a problem that the overall performance of the IMT-2000 base station controller to which the above-described conventional ATM switch is applied falls.

Accordingly, an object of the present invention is to provide an apparatus for converting an AAL5 ATM cell into an AAL2 ATM cell for allowing an AAL2 type cell to be applied to an ATM switch. have.

Another object of the present invention is to provide an apparatus for converting an AAL5 ATM cell into an AAL2 ATM cell for maximizing the efficiency of BandWeed, which is an AAL2 advantage, by adopting AAL2 rather than AAL1 when sending voice data to an ATM cell.

In order to achieve the above object, an apparatus for converting an AL5 ATM cell into an AL2 ATM cell includes a transmission FIFO block configured to receive a plurality of AAL5 ATM cells transmitted asynchronously and perform a temporal buffering function;

A 1: N demux for receiving an AAL5 ATM cell from the transmission FIFO block and separating it into multiple (N) paths using the VCI of the cell;

Each of which is connected to the 1: N demux, receives an AAL5 ATM cell from the 1: N demux, converts the AAL2 ATM cell to transmit the AAL5 ATM cell, and performs a padding processing function when the AAL5 cell is not input for a predetermined time. (N) AAL processing units;

A plurality of (N) physical interface units respectively connected to the plurality of N AAL processing units to receive and temporarily store an AAL2 ATM cell from an AAL processing unit connected thereto; And

N: 1 mux, which is connected to each of the plurality of N physical interface units, receives a plurality of N AAL2 ATM cells from the plurality of N physical interface units, mixes them through cell scheduling, and transmits the mixed N: 1 mux. It is characterized by.

1 is an upper block diagram of an IMT-2000 base station controller equipped with an apparatus for converting an AL5 ATM cell into an AL2 ATM cell, according to an embodiment of the present invention;

2 is a functional block diagram showing a configuration of an apparatus for converting an AL5 ATM cell into an AL2 ATM cell according to an embodiment of the present invention;

FIG. 3 is a functional block diagram showing a detailed configuration of an AAL processing unit in the apparatus for converting an AL5 ATM cell according to FIG. 2 into an AL2 ATM cell;

4 is a diagram illustrating the form of an AAL type 2 ATM cell defined in a general ATM forum;

5 is a view showing the form of an AAL type 5 ATM cell defined in a general ATM forum;

FIG. 6 is a reference view for explaining an operation process of an apparatus for converting an AL5 ATM cell according to FIG. 2 into an AL2 ATM cell.

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

1: ATM cell bus interface unit 2: 4: 1 mux

3: utopia interface unit 4: E1 interface unit

100: transmit FIFO block 200: 1: 4 demux

300: AAL processing unit 310: cell processing unit

311: cell header storage unit 312: AAL5 cell separation unit

320: payload extraction unit 330: AAL2 cell generation unit

340: 2: 1 mux 400: physical interface

500: 4: 1 mux

Hereinafter, an apparatus for converting an AL5 ATM cell according to an embodiment of the present invention into an AL2 ATM cell will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, an ATM cell bus interface unit 1 for receiving and interfacing an AAL5 ATM cell in real time from an ATM switch, and AAL5 from the ATM cell bus interface unit 1 is provided. 4: 1 mux (2) receiving the ATM cell and processing 4: 1 mux (4), four Utopia interface units receiving the AAL5 ATM cell from the 4: 1 mux (2) and Utopia interface ( 3) and four E1 interface units 4 respectively connected to the four Utopia interface units 3 and receiving the AAL5 ATM cells from the Utopia interface unit 3 connected thereto, and transmitting the AAL5 ATM cells to the E1 line, respectively. In the upper block of the IMT-2000 base station controller, four are mounted between the 4: 1 mux 2 and the four utopia interface units 3, respectively.

2 is a functional block diagram of an apparatus for converting an AL5 ATM cell into an AL2 ATM cell according to an embodiment of the present invention. The apparatus for converting an AL5 ATM cell into an AL2 ATM cell according to an embodiment of the present invention is a transmission FIFO (First). In First-Out block 100, 1: 4 demux 200, four AAL processing units 300, four physical interface units 400, and 4: 1 muxes. 500).

The transmission FIFO block 100 is a block for interfacing with the 4: 1 mux 2 shown in FIG. 1 according to a utopia level 1 standard. The transmission FIFO block 100 receives four AAL5 ATM cells transmitted asynchronously and performs a temporal buffering function. It is composed of FIFO structure to store 4 AAL5 ATM cells.

In addition, the 1: 4 demux 200 receives an AAL5 ATM cell from the transmission FIFO block 100 and then divides the AAL processor into four paths using the VCI (Virtual Channel Identifier) of the cell. ) Is used to send.

Meanwhile, the four AAL processing units 300 are connected to the 1: 4 demux 200, respectively, and receive the AAL5 ATM cell from the 1: 4 demux 200, convert the AAL2 ATM cell, and transmit the converted AAL2 ATM cell. When the AAL5 cell is not input for a predetermined time, the padding processing function performs a padding processing function. As shown in FIG. 3, the cell processing unit 310, the payload extraction unit 320, the AAL2 cell generation unit 330, And 2: 1 mux 340, respectively.

At this time, the cell processing unit 310 mounted in each of the four AAL processing unit 300 receives the AAL5 ATM cell from the 1: 4 demux 200 in real time and separates it into a non-voice AAL5 cell and a voice AAL5 cell. After that, the non-voice AAL5 cell is transmitted to the 2: 1 mux 340, while the voice AAL5 cell is transmitted to the payload extractor 320, and in the case of the voice AAL5 cell, the header value is copied and stored. And serves as a cell header storage 311 and an AAL5 cell separator 312.

The cell header storage unit 311 mounted in the cell processing unit 310 is a memory that stores header values of the AAL5 cell for voice.

In addition, the AAL5 cell separator 312 mounted in the cell processor 310 receives the AAL5 ATM cell from the 1: 4 demux 200 in real time and separates the non-voice AAL5 cell and the voice AAL5 cell. The non-voice AAL5 cell is transmitted to the 2: 1 mux 340, while the voice AAL5 cell is transmitted to the payload extraction unit 320, and in the case of the voice AAL5 cell, the header value is transmitted to the cell header storage unit ( To 311).

Meanwhile, the payload extracting unit 320 mounted in each of the four AAL processing units 300 receives the AAL5 cell for voice from the cell processing unit 310 in real time, and extracts the payload from the AAL2 cell. It serves to transmit to the cell generator 330.

In addition, the AAL2 cell generator 330 mounted in each of the four AAL processing units 300 reads the header copy value of the AAL5 cell for speech from the cell processing unit 310 and at the same time the payload extraction unit 320. After receiving the payload from the real-time to form a single AAL2 cell and transmits to the 2: 1 mux 340, if the AAL5 cell for voice is not input for a certain time to form an AA2 cell filled with "0" It serves to transmit to the 2: 1 mux 340. At this time, the weighting type (Waiting Time) for the current padding process is fixed to 2ms.

The 2: 1 mux 340 mounted in each of the four AAL processing units 300 is a non-voice AAL5 cell transmitted from the cell processing unit 310 and a voice transmitted from the AAL2 cell generation unit 330. After mixing the AAL2 cells, the AAL2 cell is connected to the physical interface unit 400 connected thereto.

On the other hand, the four physical interface unit 400 is connected to each of the four AAL processing unit 300, as an interface block that serves to temporarily store the AAL2 ATM cell from the AAL processing unit 300 connected to itself When one cell of 53 bytes is prepared, the " ready " signal is transmitted to the 4: 1 mux 500, and a read signal " ready_i " When received, the data enable signal and the cell start signal are transmitted together with the cell data.

In addition, the 4: 1 mux 500 is connected to each of the four physical interface units 400, and receives four AAL2 ATM cells from the four physical interface units 400 and mixes them through cell scheduling. It serves to transmit to the corresponding utopia interface unit 3 shown in FIG.

Meanwhile, as shown in FIG. 4, the AAL type 2 ATM cell 10 defined in the ATM forum has a 5-byte cell header field 11 storing various header information including VCI / VPI information, and all data. 48 bytes of CPS-PDUs (hereinafter referred to as "CPS-PDUs") 12 which are payloads. At this time, the CPS-PDU 12 includes a CPS-PDU header field 12a in which header information of the CPU-PDU 12 is stored, a plurality of CPS-SDUs 12b in which actual data of an application unit is stored, and the It consists of a plurality of CPS-SDU header fields 12c in which header information for each of the plurality of CPS-SDUs 12b is stored. In addition, the CPS-PDU header field 12a includes an OSF (Offset) field 12aa and a CPS-PDU 12 scrim that store the number of octets between the start and the end of the payload existing in the CPS-PDU 12. Is composed of a Sequence Number (SN) field 12ab in which a sequence number is stored, and a Parity (P) field 12ac for error detection of the CPS-PDU 12. The plurality of CPS-SDU header fields 12c may include a Channel Identifier (CID) field 12ca in which destination information of the CPS-SDU 12b is stored, and LI in which total length information of the CPS-SDU 12b is stored. (Length Indication) field 12cb, Packet Payload Type (PPT) field 12cc in which type information of the CPS-SDU 12b is stored, and UUI (User-) in which application distinguishing information to which the CPS-SDU 12b belongs is stored. to User Indication (12cd) field and HEC (Header Error Control) field 12ce for header error correction.

In addition, the AAL type 5 ATM cell defined in the general ATM forum 20 and 30 is an AAL type 5 ATM cell composed of a cell header field 21 and a payload CPS-PDU 22, as shown in FIG. And an AAL type 5 ATM cell 30 composed of a cell header field 31, a payload CPS-PDU 32, a padding field 33, and a trailer field 34. There are two forms. In this case, the trailer field 34 includes a CPS User-to-User Indication (CPS-UU) field 34a, a Common Part Indicator (CPI) field 34b, a length field 34c, and a cyclic redundancy check. ) Field 34d.

Next, an operation process of an apparatus for converting an AL5 ATM cell according to an embodiment of the present invention having the above-described configuration into an AL2 ATM cell will be described with reference to FIG. 6.

First, the transmission FIFO block 100 receives four AAL5 ATM cells from the 4: 1 mux 2 shown in FIG. 1 and performs a temporal buffering function, and then transmits them to the 1: 4 demux 200. do.

Then, the 1: 4 demux 200 receives the AAL5 ATM cell from the transmission FIFO block 100 and divides it into four paths using the VCI of the cell and transmits it to the corresponding AAL processing unit 300. Here, the 1: N demux 200 confirms the path of the AAL5 ATM cell through the [9, 8] 2-bit value of the VCI in the AAL5 cell header. At this time, if the [9, 8] 2-bit value of the VCI in the AAL5 cell header is "00", a path is designated to the first AAL processing unit 300, and the [9, 8] 2-bit value of the VCI in the AAL5 cell header is set. If "01", the path is designated to the second AAL processing unit 300. If the [9, 8] 2-bit value of the VCI in the AAL5 cell header is "10", the path is designated to the third AAL processing unit 300, and the AAL5 cell. If the [9, 8] 2-bit value of the VCI in the header is " 11 ", a path is designated to the fourth AAL processing unit 300.

On the other hand, the four AAL processing unit 300 receives the AAL5 ATM cell from the 1: 4 demux 200 and converts it into an AAL2 ATM cell and transmits it to the corresponding physical interface unit 400, while the AAL5 cell for a predetermined time. If no input is made, each padding process is performed.

Hereinafter, the process of the four AAL processing units 300 described above will be described in more detail. First, the cell processing units 310 respectively installed in the four AAL processing units 300 are configured from the 1: 4 demux 200. After receiving the AAL5 ATM cell in real time and separating the non-voice AAL5 cell and the voice AAL5 cell, the non-voice AAL5 cell is transmitted to the 2: 1 mux 340, while the voice AAL5 cell is the payload extractor 320 To send). At this time, in the case of the voice AAL5 cell, the header value is copied and stored. On the other hand, as described above, the method for distinguishing between the non-voice AAL5 cell and the voice AAL5 cell is distinguished using the [15, 15] 2-bit value of the VCI in the AAL5 cell header.

Then, the payload extractor 320 receives a voice AAL5 cell from the cell processor 310 in real time, extracts the payload from the cell, and transmits the payload to the AAL2 cell generator 330. At this time, the payload extraction method reads and decodes the length field value of the trailer field 34 in the payload of the AAL5 cell.

In addition, the AAL2 cell generator 330 reads the header copy value of the voice AAL5 cell from the cell processor 310 as the AAL2 header as shown in FIG. 6 and simultaneously uses the payload extractor 320. The payload is received in real time from one AAL2 cell, and then transmitted to the 2: 1 mux 340. On the other hand, the AAL2 cell generation unit 330 forms an AA2 cell filled with "0" and transmits it to the 2: 1 mux 340 when the voice AAL5 cell is not input for a predetermined time.

Then, the 2: 1 mux 340 mixes the non-voice AAL5 cell transmitted from the cell processor 310 with the voice AAL2 cell transmitted from the AAL2 cell generator 330 and then connects the physical AAL2 cell. Transmission to the interface unit 400.

On the other hand, the four physical interface unit 400 receives the AAL2 ATM cell from the AAL processing unit 300 connected to it and stores it for a while, when one cell of 53 bytes is prepared, the 4: 1 mux 500 returns to "4." When the signal “ready_i”, which is an acknowledgment signal indicating that the cell data may be transmitted from the 4: 1 mux 500, is received, the data enable signal and the cell starting point signal are transmitted together with the cell data. Transfer to the mux 500.

Then, the 4: 1 mux 500 receives four AAL2 ATM cells from the four physical interface units 400, mixes them through cell scheduling, and transmits them to the corresponding utopia interface unit 3 shown in FIG. do.

As described above, the apparatus for converting an AL5 ATM cell into an AL2 ATM cell according to the present invention can maximize the efficiency of bandwith, which is an advantage of AAL2, by adopting AAL2 instead of AAL1 when sending voice data to an ATM cell. At the same time, the AAL2 type cell can be applied to ATM switches.

Claims (5)

A transmission FIFO block receiving a plurality of AAL5 ATM cells transmitted asynchronously and performing a temporal buffering function; A 1: N demux for receiving an AAL5 ATM cell from the transmission FIFO block and separating it into multiple (N) paths using the VCI of the cell; Each of which is connected to the 1: N demux, receives an AAL5 ATM cell from the 1: N demux, converts the AAL2 ATM cell to transmit the AAL5 ATM cell, and performs a padding processing function when the AAL5 cell is not input for a predetermined time. (N) AAL processing units; A plurality of (N) physical interface units respectively connected to the plurality of N AAL processing units to receive and temporarily store an AAL2 ATM cell from an AAL processing unit connected thereto; And N: 1 mux, which is connected to each of the plurality of N physical interface units, receives a plurality of N AAL2 ATM cells from the plurality of N physical interface units, mixes them through cell scheduling, and transmits the mixed N: 1 mux. An apparatus for converting an AL5 ATM cell into an AL2 ATM cell. The method of claim 1, Wherein said 1: N demux confirms a path of an AAL5 ATM cell through a [9, 8] 2-bit value of a VCI in an AAL5 cell header, and converts an AL5 ATM cell into an AL2 ATM cell. The method of claim 1, The N (N) AAL processing units receive the AAL5 ATM cells from the 1: N demux in real time, separate them into non-voice AAL5 cells and voice AAL5 cells, and transmit the header values in the case of the voice AAL5 cells. A cell processing unit for copying and storing the copy; A payload extraction unit configured to receive a voice AAL5 cell from the cell processor in real time and extract and transmit a payload from the cell; The cell processor reads the header copy value of the voice AAL5 cell and receives the payload from the payload extractor in real time to form and transmit one AAL2 cell, while transmitting the voice AAL5 cell for a predetermined time. An AAL2 cell generator that forms and transmits an AA2 cell filled with “0” if it is not inputted; And AAL5 ATM cells comprising a 2: 1 mux mixed with a non-voice AAL5 cell transmitted by the cell processor and a voice AAL2 cell transmitted by the AAL2 cell generator and then transmitted to a physical interface connected to the cell. AAL2 A device that converts ATM cells. The method of claim 3, wherein The cell processing unit converts an AAL5 ATM cell into an AAL2 ATM cell, wherein the AAL5 cell is divided into a non-voice AAL5 cell and a voice AAL5 cell using the [15, 15] 2-bit value of the VCI in the AAL5 cell header. . The method of claim 3, wherein The cell processor may include a cell header storage unit configured to store a header value of a voice AAL5 cell; And The AAL5 ATM cell is received in real time from the 1: N demux and separated into a non-voice AAL5 cell and a voice AAL5 cell, and then the non-voice AAL5 cell is transmitted to the 2: 1 mux while the voice AAL5 cell is the payload. And an AAL5 cell separating unit which transmits to an extracting unit and continuously updates the header value in the cell header storage unit in the case of an AAL5 cell for voice, converting an AL5 ATM cell into an AL2 ATM cell.