KR19990075873A - Subscriber Asymmetric Digital Subscriber Line Modem of Asymmetric Digital Subscriber Line System - Google Patents

Abstract

In the ADSL modem of subscriber side of an asymmetric digital subscriber line (ADSL) system, the ATM handler and the SAR processing unit are composed of one device element, and the ATM-based data is processed as Ethernet packet data, thereby making it possible for another network of a PC or a workstation. The present invention relates to a subscriber side ADSL modem of an ADSL system capable of interfacing with an ATM system. Through the handler, it converts into ATM cell data, and then, through the SAR processing unit, processes Ethernet packet data of AAL5 type CPCS-PDU and transmits it to the network, and conversely, Ethernet packet data of AAL5 type CPCS-PDU transmitted from the network is transmitted. The ATM data is processed by the ATM handler. Through the DMT transceiver, the line driver and the splitter to transmit to the CO along with the POTS call signal, the ATM handler and SAR processing unit in the subscriber-side ADSL modem in the ADSL system as a single interworking block By processing the ADSL service data and the control signal based on the Ethernet packet data, it is easy to interface with the network, and the circuit configuration is simpler than in the related art, resulting in cost reduction.

Description

Subscriber-Side Asymmetric Digital Subscriber Line Modem in Asymmetric Digital Subscriber Line System

According to the present invention, an Asynchronous Transfer Mode (ATM) handler and a Segmentation and Reassembly Sublayer (SAR) processor are provided in a subscriber side ADSL modem of an Asymmetric Digital Subscriber Line (ADSL) system. Subscriber's ADSL system that can interface with other network of PC or work station by processing ATM-based data into Ethernet packet data It is about a modem.

In general, ADSL system can provide not only telephone service but also interactive service such as Video Of Demand (VOD) service, data service, Internet service, etc. using existing telephone line. As shown in FIG. 1, a VOD server 1 for providing a VOD service, an Internet server 2 for providing an Internet service, and a VOD server 1 and an Internet server 2 are provided. ATM switching unit 4 for processing and switching service data and control signals provided by the ATM cell and data and control signals output from the ATM switching unit 4 and plain old telephones output from the telephone exchange 5 Service) Central office consisting of ADSL line matching unit 6 which multiplexes a call signal into an ADSL signal and modulates it into an analog signal and transmits it to an existing telephone line (hereinafter referred to as 'CO') (3); Call me Receiving the ADSL signal of the CO (3) transmitted through the in and separated into a data and control signal and a POTS call signal to each ADSL modem (7) for outputting the corresponding service signal through the TV, PC, telephone, etc. It is composed.

In the ADSL system configured as described above, the ADSL service is transmitted at a maximum of 2 Mbps from the CO (3) to the ADSL modem (7) and 640 Mbps from the ADSL modem (7) to the CO (3), where the CO (3) and the ADSL modem ( 7) POTS call signal is transmitted / received along with data and control signal for ADSL service.

In the ADSL system configured as described above, the conventional subscriber-side ADSL modem 7 which interfaces with other networks of a PC or workstation by processing ATM-based data into Ethernet packet data is shown in FIG. 3) a splitter 10 which separates the ADSL signal transmitted from the data and control signal and the POTS call signal, or combines the input data and control signal and the POTS call signal into the ADSL signal and transmits the signal to the CO 3. And a line driver for line matching the data and control signal and the POTS call signal separated by the splitter 10 or line matching the input data and control signal and the POTS call signal to the splitter 10. 11 and data and control signals passed through the line driver 11 are converted into digital signals and then DMT demodulated and transmitted in byte units or inputted. DMT (Descrete Multi-Tone) transceiver (12) for configuring data and control signals in units of data into an ADSL superframe, converting DMT, and converting the analog signal into an analog signal for transmission to the line driver 11. The ATM handler processes the data and the control signal of the byte unit transmitted from the DMT transceiver 12 by ATM cell processing or the ATM data of the input data and the control signal to the DMT transceiver 12 by byte unit processing. (Handler) 13, the ATM cell processed data and the control signal in the ATM handler 13 is divided and transmitted as Ethernet packet data, or the combined Ethernet packet data is input to the ATM handler ( 13, the SAR processing unit 14 to transmit to the transmission speed, Ethernet packet data transmitted from the SAR processing unit 14 and Ethernet packet data transmitted from the subscriber network Is controlled to 10BasedT to perform an interface, a transformer 16 for performing low pass filtering and impedance matching of transmitted / received Ethernet packet data, and operations of the components 11 to 15. And a control unit 17 for controlling the state.

The byte interface is used between the DMT transceiver 12 and the ATM handler 13 of the conventional subscriber side ADSL modem 7 configured as described above, and the UTOPIA (Universal Test & Operations PHY) is used between the ATM handler 13 and the SAR processor 14. Interface for ATM) Uses Level I interfaces.

However, in the conventional subscriber-side ADSL modem 7 configured as described above, although the ATM handler 13 and the SAR processing unit 14 can be integrated into one configuration, they are separately configured using separate device elements. As a result, the software function is complicated and the circuit is not simple, and thus, the overall ADSL service data transmission / reception process is unnecessarily complicated.

The present invention has been made to solve the above problems, the object of which is to configure the ATM handler and SAR processing unit in the subscriber-side ADSL modem in the ADSL system as one interworking block (Interworking Block) ATM-based ADSL service By processing data and control signals as Ethernet packet data, it is possible to easily interface with other networks of PCs or workstations, and provides subscriber-side ADSL modems of ADSL system, which can reduce costs due to simple circuit configuration. It's there.

1 is an overall configuration diagram of a typical asymmetric digital subscriber line system,

2 is a block diagram of a subscriber side ADSL modem in a conventional asymmetric digital subscriber line system;

3 is a block diagram of a subscriber side ADSL modem of an asymmetric digital subscriber line system capable of interfacing Ethernet packet data according to the present invention;

4 is a detailed configuration diagram of the SAR processing unit of FIG.

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

20: splitter 21: line driver

22: DMT transceiver 23: SAR processing unit

24: Transceiver 25: Transformer

31: ATM handler 32: SAR

33: memory 34: processor

The subscriber side ADSL modem of the ADSL system of the present invention for achieving the above object is configured by the ATM handler and SAR processing unit in the ADSL modem as a single interworking block to provide ATM-based ADSL service data and control signals transmitted from the DMT transceiver. After converting into ATM cell data through ATM handler, processing it into Ethernet packet data of CPCS-PDU of AAL5 type through SAR processing unit and transmitting it to network, and reversely, Ethernet packet data of CPCS-PDU of AAL5 type CPCS-PDU transmitted from network Splitting and processing the divided Ethernet packet data through the ATM handler ATM cell to transmit to the CO with the POTS call signal through the DMT transceiver, the line driver and the splitter.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the subscriber-side ADSL modem of the ADSL system according to the present invention.

3 is a block diagram of an ADSL modem at the subscriber side of an ADSL system capable of interfacing Ethernet packet data according to the present invention, wherein the ADSL signal transmitted from the CO 3 is separated into data and control signals and a POTS call signal, or inputted. A splitter 20 which combines the data and the control signal and the POTS call signal into an ADSL signal and transmits it to the CO 3, and lines or inputs the data and control signal and the POTS call signal separated by the splitter 20. DMT demodulation after converting the data and control signal and the POTS call signal to the line driver 21 for transmitting to the splitter 20 and the data and control signal passed through the line driver 21 into digital signals. By byte unit or convert the input byte unit data and control signal into ADSL superframe, DMT modulate and convert it into analog signal. DMT transceiver 22 to be transmitted to the driver 21 and the byte unit data and control signals transmitted from the DMT transceiver 22 by processing the ATM cell divided and transmitted as Ethernet packet data, or Ethernet packet input The SAR processing unit 23 combines the data and transmits the data and the control signal to the DMT transceiver 22 by byte unit after processing the ATM cell, and the Ethernet packet data transmitted from the SAR processing unit 23 and the subscriber network are transmitted. Transceiver 24 for performing an interface by adjusting the transmission rate of the Ethernet packet data to 10BasedT, and transformer 25 for low pass filtering and impedance matching of the transmitted and received Ethernet packet data.

4 is a detailed configuration diagram of the SAR processing unit 23 of FIG. 3, wherein the SAR processing unit 23 transmits or transmits byte data and control signals in an ATM cell transmitted from the DMT transceiver 22, or is inputted. ATM handler 31 for processing data and control signals to ATM cells and transmitting the byte data to the DMT transceiver 12 in bytes, and ATM cell processed data and control signals from the ATM handler 31 to be divided into Ethernet packet data. The SAR 32 which combines the transmitted or received Ethernet packet data and transmits the data and the control signal to the ATM handler 31 and the memory 33 which stores the data and the control signal processed by the SAR 32. And a processor 34 for controlling the operation and state of the ATM handler 31 and the SAR 32, and for controlling the operation and state of the components 21, 22, and 24 of the ADSL modem.

When explaining the function of each component of the interface circuit of the present invention configured as described above in more detail, the splitter 20 is designed as a high pass filter (HPF) is configured independently in the modem, CO ( It separates the ADSL signal received in 3) into data and control signal and POTS call signal, and combines data and control signal and POTS call signal into ADSL signal and transmits it to CO (3).

The line driver 21 is used to maintain high performance in a hybrid network, and plays a role of enhancing the processing effect of noise and distortion.

The DMT transceiver 22 is divided into subblocks of a digital interface, a DMT processor, and an analog front-end to perform the following functions.

That is, ANSI standard ANSI T1.413 support, multiplexing and demultiplexing, framing and deframing, management, initialization control, cyclic redundancy check (CRC) and scrambling, interleaving, and reed-solomon solomon) Forward Error Correction, Trellis Encoding and Decoding, DMT Modulation and Demodulation, Echocellation for ADSL, A / D Conversion and Receive Path It performs filtering, D / A conversion, transmission path filtering, and adaptive rate mode.

The SAR processor 23 supports self-processing for Ethernet over ATM cell data, supports AAL5 (ATM Adaptation Layer 5) mode, AAL0 is optional, CLP (Cell Loss Priority), and a jam indication, and SAR The ATM handler 31 in the processor 23 performs the injection / extraction of ATM cells, the check of the Virtual Path Identifier (VPI) / Virtual Path Identifier (VCI), and the ATM cell delineation since the service transmitted / received is Ethernet over ADSL. ATM handling functions such as cell header interpretation, physical layer OAM (Operation Administration and Maintenance), mux and scrambling of fast and interleaved bytes are supported.

The SAR 32 uses a separate queue to use the interrupt report for the channel and to report errors, and the cell size supports 53 bytes.

When separated, the AAL5 cell format controls direct reassembly of Common Part Convergence Sublayer-Protocol Unit Data (CPCS-PDU), CRC32 check, and padding of CPCS-PDU in host memory.

In this case, the AAL5 cell format reports CS-UU (Convergence Sublayer-User to User information), CPI (Common Part Indicator), length report, directly separates the CPCS-PDU from the host memory, and performs CPCS-PDU padding. It also generates CRC32 and automatically performs last cell display, CS-UU, CPI, and length.

The processor 34 performs system-wide control, controls, boots, and resets the DMT transceiver 22, and performs an ATM handler 31, an idle cell, and a VPI / VCI preset. do.

And performs a cable disconnect and link initialization state, a received HEC error cell interrupt, a received short cell interrupt, a received cell symbol interrupt, and a symbol error count for the SAR 32. Transmit cell count, receive cell count, and receive HEC error count.

The transceiver 24 is a functional block for supporting a subscriber interface. The MAC controller uses a 10BasedT transceiver, and the encoder converts NRZ data into Manchester data and supplies signals required for data communication.

Referring to the operation of the subscriber-side ADSL modem in the ADSL system that can interface the Ethernet packet data of the present invention configured as described above are as follows.

When the ADSL signal transmitted from the CO 3 through the splitter 20 is separated into data and control signals and POTS call signals for the ADSL service, the data and control signals for the ADSL service are passed through the line drive 21. Is sent to the DMT transceiver 22.

Subsequently, in the DMT transceiver 22, the line drive 21 converts the data and the control signal, which have been processed for noise and distortion, into a digital signal, and then DMT demodulates the data and transmits the data to the SAR processor 23 in units of bytes.

Accordingly, the ATM handler 31 of the SAR processor 23 processes the ATM data and the control signal of the byte unit transmitted from the DMT transceiver 22 to the SAR 32 by processing the ATM cell.

Then, the SAR 32 divides the ATM cell-processed data and the control signal in the ATM handler 31 and reconstructs the packet data of the Ethernet packet through the transceiver 24 and the transformer 25 by reconstructing the ACS-PDU format of the AAL5 type. Send to the network.

At this time, the transmission rate of the transmitted Ethernet packet data is adjusted to 10BasedT by the transceiver 24 to be transmitted.

On the other hand, the process of transmitting the Ethernet packet data transmitted from the network to the CO (3) is a process to perform the reverse process will be omitted the description of the operation.

As described above, the present invention configures the ATM handler and the SAR processing unit in the subscriber-side ADSL modem in the ADSL system as one interworking block to process ATM-based ADSL service data and control signals as Ethernet packet data. It can be easily interfaced with, as well as the circuit configuration is simple compared to the conventional has the effect of bringing down the cost.

Claims (2)

A splitter 20 which separates the ADSL signal transmitted from the CO 3 into data and control signals and a POTS call signal, or combines the input data and control signals and POTS call signals into an ADSL signal and transmits the signal to the CO 3. A line driver 21 for line matching the data and control signal separated from the splitter 20 with the POTS call signal, or line matching the input data and control signal with the POTS call signal to the splitter 20; After converting the data and control signals passed through the line driver 21 into digital signals, DMT demodulates them and transmits them in byte units, or configures the input byte data and control signals in ADSL superframes to perform DMT modulation. The DMT transceiver 22 converts an analog signal to the line driver 21 and transmits data and control signals in byte units transmitted from the DMT transceiver 22. The ATM processor processes the ATM cell, divides the data, and transmits the Ethernet packet data, or combines the input Ethernet packet data with the ATM processor to process the data and the control signal to the DMT transceiver 22 by byte unit. Low-pass filtering of the transceiver 24 to perform the interface by adjusting the transmission rate of the Ethernet packet data transmitted from the SAR processing unit 23 and the Ethernet packet data transmitted from the subscriber network to 10BasedT, and the transmitted / received Ethernet packet data And a transformer (25) for performing impedance matching. Subscriber side ADSL modem of asymmetric digital subscriber line (ADSL) system. The method according to claim 1, wherein the SAR processor 23 performs ATM cell processing of byte data and control signals transmitted from the DMT transceiver 22, or transmits the input data and control signals by ATM cell processing. The ATM handler 31 transmitting the DMT transceiver 12 to the DMT transceiver 12 and the ATM cell-processed data and the control signal are transmitted as Ethernet packet data or by combining the input Ethernet packet data. A SAR 32 for transmitting data and control signals to the ATM handler 31, a memory 33 for storing data and control signals processed in the SAR 32, the ATM handler 31 and a SAR ( Subscriber of an asymmetric digital subscriber line (ADSL) system, characterized in that it comprises a processor 34 that controls the operation and status of the 32 and controls the operation and status of each of the components 21, 22, and 24 of the ADSL modem. Side ADSL modem.