KR100310845B1 - Asymmetric digital subscriver line multiplexing transmission equipment - Google Patents

Abstract

PURPOSE: An ADSL(Asymmetric Digital Subscriber Line) multiplexing transmission apparatus is provided to perform a connection process with ATM network by multiplexing a multitude of ADSLs. CONSTITUTION: A TP line matching portion(17) is connected with an external PSTN(Public Switched Telephone Network) exchange, a multitude of TP lines, and an ADSL channel. The TP line matching portion(17) is connected with the TP lines by multiplexing the PSTN and the ADSL channels. The TP line matching portion(17) filters signals of the TP lines to each channel band. A subscriber portion(15) is matched with an ATM cell bus portion(14) and a plurality of ADSL modem channels in order to convert ADSL signals to ATM cells or the ATM cells to the ADSL signals. A cell multiplexing portion(13) is used for multiplexing ATM cells of a serial link and a cell bus within a unit sub-system. An ATM layer processing portion(12) performs a multiplexing/demultiplexing function, a control function, and a header conversion function. An ATM physical layer processing portion(11) performs functions for generating or testing a head of the ATM cell, generating or recovering a transmission frame, and bit timing. A network synchronization portion(16) is used for generating a reference clock within a system.

Description

Asymmetric Digital Subscriber Line Multiplexed Transmission Device {ASYMMETRIC DIGITAL SUBSCRIVER LINE MULTIPLEXING TRANSMISSION EQUIPMENT}

The present invention relates to the implementation of a device that can transfer high-speed data to each other using a conventional telephone subscriber network among a variety of access network, in particular, multiplexed multiple asymmetric digital subscriber line input and output from the subscriber in the home network Asymmetrical digital subscriber line multiplexed transmission device connected to the present invention.

As interactive multimedia services such as VOD (Video On Demand) service and Internet service have become a reality, the desire for high speed interactive service among general end users has increased, so that interactive multimedia using CATV network, telephone network, etc. Many studies on services have been conducted. In particular, thanks to the development of DSP (Digital Signal Processing) technology, ADSL (Asymmetric Digital Subscriber Line, hereinafter called ADSL) modem can be used for high-speed information transmission using existing telephone network. Compared to other configurations, it is recognized as important in various aspects, such as low cost and ease of installation cost, and risk of failure of new network construction.

The ADSL modem is largely divided into a carrier amplitude / phase modulation (CAP) method and a discrete multi-tone (DMT) method according to a line coding method. The Carrier Amplitude / Phase Modulation (CAP) method has advantages in the implementation of a modem chip due to the simplification of the coding method. However, characteristics such as noise immunity and flexible data rate according to line conditions are provided. As a result, attention is currently focused on the Discrete Multi-tone (DMT) modem.

An ADSL transmission system connected to an Ethernet network, which is an example of the prior art of the ADSL multiplexing transmission device, is an Ethernet network having a speed of 10 Mbps that is connected to a higher level, and is easily connected to an existing Ethernet network. On the other hand, there is a structural problem in the efficient multiplexing and demultiplexing of multiple ADSL modems with transmission rates up to 8Mbps.

As another example, it may be developed as an internal subscriber form of a particular ATM switch, which has the advantage that ADSL can implement control and maintenance functions similar to ATM subscribers such as STM-1, DS3, DS1, etc., which were developed in advance. On the other hand, there was a problem in that the ATM switch must be purchased and installed for the ADSL service.

Accordingly, an object of the present invention is to efficiently utilize the characteristics of the DM modem which can flexibly vary the transmission speed according to the characteristics of the transmission line, and each asymmetric digital subscriber line even under the full load of the system with respect to the maximum transmission speed of the modem. It is possible to guarantee the transmission speed transparent to the subscribers in the multiplexed transmission device, and to freely vary the number of subscribers, if necessary, to be connected to the high speed ETM network, and in particular with any ETI device that complies with the UNI standard of the ETI Forum. Another object of the present invention is to provide an asymmetric digital subscriber line multiplexing transmission device that can be easily connected.

In order to achieve the above object, an embodiment of the present invention provides an asymmetric digital subscriber line multiplexing transmission apparatus, which is connected to an external PSI and TPI lines and an asymmetric digital subscriber line channel. Multiplexing and connecting to the tip line and filtering the signal of the tip line to each channel band to separate the signal output line, the top of the EMT Embus bus unit and a plurality of asymmetric digital subscriber line down A subscriber unit that matches a modem channel, converts an asymmetric digital subscriber line signal into an ATMS cell, converts an ATMS cell into a non-digitized digital subscriber line signal, and multiplexes / demultiplexes information between a modem channel and an ATMS cell bus; To the top of the serial link and to the bottom of the ETIMSell on the cell bus in the unit subsystem. Multiplexing / demultiplexing function, control function for compliance with regulatory traffic, header conversion to find destination address through serial link matching to each unit subsystems An ETEM physical layer processor that performs a function of an ETEM physical layer such as a head generation and inspection of the ETEMcell, cell synchronization, generation and restoration of a transmission frame, bit timing, and a system; Characterized in that it consists of a network synchronizer for generating and distributing the reference clock therein.

1 is a block diagram of an ADSL (Asymmetric Digital Subscriber Line) multiplexing transmission apparatus according to the present invention

2 is a detailed configuration diagram of the TP line matching unit according to the present invention

3 is an internal configuration diagram of a subscriber unit according to the present invention

4 is an internal configuration diagram of a cell multiplexing unit according to the present invention;

5 is an internal configuration diagram of an ATM layer processing unit according to the present invention

6 is an internal configuration diagram of an ATM physical layer processing unit according to the present invention.

7 is a diagram illustrating an internal configuration of the network synchronizer unit according to the present invention.

8 is a cell format diagram within an apparatus according to the present invention;

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention, such as specific processing flows. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. Detailed descriptions of well-known functions and configurations that are determined to unnecessarily obscure the subject matter of the present invention will be omitted.

A configuration diagram of an ADSL multiplexing transmission apparatus according to the present invention is shown in FIG. Described with reference;

ADSL multiplexing transmission apparatus according to the present invention is connected to the ATM network through the STM-1 link 18 that satisfies the standard of ATM Forum UNI (User Network Interface) 3.1 / 4.0 to the upper, and the ADSL subscriber from the premises It is connected to TP lines 173. The internal configuration of the ADSL multiplexer is composed of an ATM physical layer processor 11, an ATM layer processor 12, a cell multiplexer 13, a subscriber 14, TP line matching unit 15.

As shown in FIG. 2, the TP line matching unit 17 includes a T-connection 21, a high pass filter 23, and a low pass filter 22, and are connected to the TP telephone line, the POTS channel, and the ADSL channel, respectively.

The internal operation of the TP line matching unit 17 frequency-multiplexes the POTS channel 172 coming from the PSTN switch and the ADSL channel 171 encoded from the ADSL modem through the T-connection 21 in the signal separator 174 to the TP telephone line 173. In addition, the signal from the TP telephone line 173 is separated into the POTS channel and the ADSL channel through the low pass filter 22 and the high pass filter 23 in the signal separator 174, and transmitted to the subscriber part 15 in the PSTN switch and the ADSL multiplexing transmitter. The characteristics of the high and low pass filters are disclosed in DMT modem databooks such as MOTOROLA and AMATI.

The subscriber unit 15 is capable of accommodating four ADSL modems per card as shown in the subscriber unit internal configuration of FIG. 3, and up to 16 subscriber unit cards can be mounted per one subsystem in the ADSL multiplexing transmission apparatus of the present invention. Can be.

The subscriber unit 15 is mutually matched with different processing units 14 and 17 by ATM cell buses up and four ADSL modem channels down. The internal structure is composed of a DMT modem unit 31, a TC (transmission convergence) unit 32, a cell transmission processing unit 34, a cell reception processing unit 35, an ATM cell bus matching unit 36, and a control unit 33.

The operation of the subscriber unit 15 extracts the cell boundary from the TC unit 32 and transmits the ATM data inputted through the DMT modem unit 31 to the cell reception processor 35 through UTOPIA matching. Like the internal cell format, the corresponding channel of the information received from the ATM standard 53 bytes and the location information of the subscriber card are added to the ATM cell matching unit 36 with an overhead of 3 bytes, and the ATM cell matching unit 36 transmits the ATM cell bus unit. Transfer to cell multiplexer 13 through 14. In the case of the downlink ATM cell transmitted from the ATM cell bus unit 14, the ATM cell bus matching unit 36 monitors the ATM cell bus from the ATM cell bus unit 14, and the bits of the corresponding card in the internal cell format of FIG. If C0) is 0, the corresponding information is read and transmitted to the cell transmission processor 34. The cell transmission unit of the cell transmission processing unit 34 checks the M bit (multiplexing bit) in the header of the input cell, and if it is 0, reads and converts the output VPI / VCI value from the P-TO-MP header conversion table through the multiplexing identifier. When the M bit is 1, the output VPI / VCI is transferred to the DMT modem unit 31 through the TC unit 32 without being converted to the TP line matching unit 17. The control unit 33 transmits / receives IPC (Interprocessor Communication) information such as P-TO-MP header conversion table information input from the control unit (44 in FIG. 4) of the cell multiplexer 13 through the VME bus, and all resources in the subscriber unit 15 are received. Perform management and control on

Herein, the internal cell format in the aforementioned device of FIG. 8 will be described;

The internal cell format indicates a subsystem identifier (S7 to S0) in a standard ATM cell, and this value is used for routing only in the ATM layer processor 12, and the subscriber card identifier (C15 to C0: 0 is designated) is a subsystem. Designate a subscriber card determined by the location within. It consists of ADSL modem channel identifier (L0, L1: 0 is designated), M bit indicating multicasting, and I / U bit indicating IPC or subscriber cell in channel identification byte. In particular, the function of the channel identification byte is subscriber cell multicasting when M = 0, and the remaining 7 bits are multiplexed identifiers and used as an identifier for head transformation of the multi-transmission output cell in the cell transmission processor 34 of the subscriber unit 15. In addition, when M and I / U have a value of 10, the subscriber cell Point-to-Point, and a value of 11 represent an IPC cell.

The cell multiplexer 13 transfers the cells multiplexed through the ATM cell bus at the subscriber unit 15 to the ATM layer processor 12 through the link matching unit 41, and transfers the data transmitted through the serial link from the ATM layer processor 12. It performs the function of transferring to the bus. Configuration and operation are the same as in FIG. Referring to the configuration and the internal operation through the internal configuration diagram of the cell multiplexer of Figure 4;

IPC cell from ATM cell bus matching unit 43 and control unit 44 which multiplexes / demultiplexes the cell by reading and writing a round-robin time division method from subscribers 15 matching the ATM cell bus unit 14. IPC extraction and insertion section 42, which is responsible for extraction of the IPC cell from the insertion and link matching section 41, converts the parallel signal inputted from the IPC extraction and insertion section 42 into a serial signal and transfers it to the ATM physical layer processing section 11, The link matching unit 41 converts the serial signal from the link into the parallel signal to the IPC extracting and inserting unit 42, and processes the IPC cell extracted from the IPC extracting and inserting unit 42. And the IPC data transmitted from the subscriber unit 15 through the VME bus to the IPC extraction and insertion unit 42 and to the control unit 44 that manages and controls all resources in the card. It is configured and works.

The ATM layer processor 12 multiplexes the link signals input to the multiplexer multiplexer 13, and is responsible for OAM, routing, and UPC (User Parameter Control) functions for the multiplexed cells and ATM cells input from the ATM network. The configuration and operation are as shown in FIG. An internal configuration diagram of the ATM layer processor 12 of FIG. 5 will be described;

The link matching unit 56 converts the serial link signals input from the cell multiplexer 23 of each subsystem into parallel UTOPIA form, adds the identifier (1 byte) of the corresponding subsystem from the input internal cell format, and transfers them to the routing unit 54. do. The multiplexing / demultiplexing unit 55 performs multiplexing / demultiplexing by reading / writing a corresponding port of the link matching unit 56 in a round-robin time division manner. The routing unit 54 converts the header to the destination virtual path identify / virtual channel identify (VPI / VCI) so that the ATM cells transmitted to the upper and lower nodes can find the correct destination. The UPC unit 53 checks whether the traffic specified for the cell transmitted in each direction is satisfied. The OAM unit 52 performs an OAM function of the ATM layer such as PM (Performance Monitoring) and CC (Continuity Check). In addition, the UTOPIA matching unit 51 performs matching to UTOPIA, which is the physical layer standard matching of the ATM forum, for matching with the ATM physical layer processing unit 11. In addition, to increase the reliability of the system, the ATM layer processing unit 12 is implemented by hardware redundancy of a hot / standby method.

In the internal configuration diagram of the ATM physical layer processor of FIG. 6, the ATM physical layer processor 11 performs physical layer functions such as HEC (Head Error Collection) head generation and inspection, cell synchronization function, transmission frame generation and restoration function, and bit timing. It consists of an ATM physical layer unit 63, an optical transmitter 61, and an optical receiver 62.

Also, the network synchronizer 16 generates and decomposes a reference clock in the system through an external reference clock and a recovery clock extracted from the ATM physical layer processor 12. Its configuration and operation perform the PLL function with the configuration and operation as shown in FIG.

The clock selection and reference clock extractor 71 extracts a reference clock of 4 KHz by selecting from an external reference clock (2.048 MHz) and a network extraction clock (19.44 MHz). The VCXO section 75 generates its own clock of 46.94943 MHz, which clocks 19.44 MHz at the clock synthesizer section (46 MHz to 19.44 MHz). The phase detector 72 controls the VCXO unit 75 by counting the phase change between the reference clock 4KHz and 19.44MHz to generate an accurate 19.44MHz. The clock synthesizer section (19.44 MHz to 23.4747 MHz) 73 synthesizes the system clock, which is then sent to each part of the system through the clock divider 74.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible 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 defined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, the present invention efficiently utilizes the characteristics of the DMT modem, which can flexibly vary the transmission speed according to the characteristics of the transmission line, and each ADSL multiplexed transmission even in the full load state of the system with respect to the maximum transmission speed of the modem. It is possible to guarantee a transparent transmission speed for subscribers in the device, freely variable number of subscribers, if necessary, to be connected to a high speed ETM network, and in particular to be easily connected to any ATM device that conforms to the UNI Forum of ATM Forum. It can be effective.

Claims (3)

In the asymmetric digital subscriber line multiplexing transmission device, It is connected to an external PTI and TPI lines and an asymmetric digital subscriber line channel, and multiplexes the PTI and asymmetric digital subscriber line channels to connect to the TPI line and filters the signal of the TPI line into each channel band. Tipi line matching unit for separating and outputting the signal, It is matched with a plurality of asymmetric digital subscriber line modem channels in the upper part of the EMT Embus bus unit, and converts the asymmetric digital subscriber line signal into an AMT cell, and converts the AMT cell into a non-digital digital subscriber line signal. And a subscriber unit for multiplexing / demultiplexing information between ETMS buses, A cell multiplexer which multiplexes / demultiplexes the ETM cells on the cell buses in the unit subsystems, ETIM layer processing unit that performs multiplexing / demultiplexing function, control of compliance with regulatory traffic, header conversion function to find destination address through serial link matching to utopia matching and subunits to lower unit, An ETM physical layer processor for performing functions of an ETM physical layer such as head generation and inspection of the ETM cell, cell synchronization, generation and restoration of a transmission frame, and bit timing; And a network synchronizer for generating and distributing reference clocks in the system. The method of claim 1, wherein the subscriber unit; It is composed of a DMT modem, a TS transmission unit, a cell transmission processing unit, a cell receiving processing unit, an ETMScell bus matching unit, and a control unit, and extracts a cell boundary from the TCM unit. When sending to the receiver, the cell receiver adds the card and modem channel information of the corresponding information to the ATMS matching unit, and the ATMS cell matching unit outputs the information to the ATMS cell bus, and the corresponding card on the ATMS cell bus. For the information transmitted to the cell head through the monitoring of the cellbus, it monitors the bits of the card in the internal head, extracts the information, and sends it to the cell transmitter for converting the output head when the cell is a multicasting request cell. An asymmetric digital subscriber line multiplexing transmission device, characterized in that for transmitting information through. The method of claim 1, wherein the cell multiplexing unit; An EMT Embus bus matching unit for multiplexing or demultiplexing cells by reading or writing EMT Ems in a round-robin time division scheme; A control unit which manages and controls all resources in the card and performs a communication function with the upper control unit and the lower control unit; An IPC extracting and inserting unit which is responsible for extracting the IPCcell from the upper part and inserting the IPCcell to the upper part, An asymmetric digital subscriber line multiplexing transmission device, characterized in that the link matching unit for transmitting and receiving information with the upper layer.