KR19990076070A - Subscriber service request interface device of asymmetric digital subscriber line system - Google Patents

Abstract

The present invention is located in the central station in the ADSL system that enables VOD, data, Internet service, etc., as well as telephone service by the existing telephone line, ADSL multiplexing / demultiplexing, modem subscriber of the ADSL ATM multi-device to interface with the subscriber As a line interface device, ATM-based service data is modulated by the DMT method to service subscribers using a telephone line, and the effects of receiving a large number of subscribers by signaling, reducing costs per line, and reducing power consumption when dialing up The present invention relates to a subscriber service request interface device for an asymmetric digital subscriber line system.

Description

Subscriber Service Request Interface Device for Asymmetric Digital Subscriber Line System

The present invention relates to a subscriber service request interface device of an asymmetric digital subscriber line (ADSL) system. Specifically, the present invention relates to video on demand (VOD), data, and Internet services as well as telephone service by an existing telephone line. Modem subscriber line interface device of ADSL ATM (Asynchronous Transfer Mode) multi-device which is located in a central office (CO) in ADSL system that enables the system to interface with subscribers and interfaces with subscribers. Service data is serviced to subscribers using telephone line by modulating service data using DMT (discrete milti-tone) method, and it is effective to accept multiple subscribers, reduce cost per line and reduce power consumption by dial-up signaling. Subscriber service request interface device of asymmetric digital subscriber line system rface system for subscriber service requirement of asymmetric digital subscriber line system.

Single carrier modulation (SCM) methods such as quadrature amplitude modulation (QAM) and carrierless amplitude and phase modulation (CAP), which have been the mainstream of transmission technology, have been used for attenuation, distortion, echo, and multipath The effects of noise, such as multi paths, are large, and TDM (time division multiplex) -based transmission methods do not flexibly cope with the upcoming broadband service market, and there is one subscriber line interface per line of modem interface. The disadvantage is that the service is expensive for end-to-end service, and the interface device is always active, resulting in unnecessary power consumption.

An object of the present invention for eliminating this drawback is located in the central station in the ADSL system that enables VOD, data, Internet service, etc., as well as telephone service by the existing telephone line, and ADSL multiplexing / demultiplexing, interface with subscribers Modem subscriber line interface device of ADSL ATM multi-device which is designed to service subscriber by using telephone line by modulating ATM-based service data by using DMT method. An object of the present invention is to provide a subscriber service request interface device for an asymmetric digital subscriber line system, which can reduce costs and reduce power consumption.

The subscriber service request interface device of the asymmetric digital subscriber line system of the present invention for achieving the above object multiplexes / demultiplexes the data transmitted between the subscriber multiplexer and the DMT & controller, and parses the bidirectional ATM interface into a handler. The ATM interface unit separates the signal from the interleaver signal and performs each head error connection, scrambling, ADSL frame, ADSL superframe, and program memory from CPU clock program memory. DMT & control unit that stores instruction opcodes and data values, and detects digital off-hooks of lines detected by service requests by remote ADSL modem dial-up, and idles subscriber lines according to these digital on / off hooks. Or active A control unit for controlling and switching a state, an ADSL line interface unit for converting a downlink DMT signal into an analog signal or a downlink analog DMT signal into a digital signal, receiving a DMT signal, and matching line impedance; Transmits the ADSL signal obtained by frequency division multiplexing the POTS signal, which is an analog telephone signal from the DMT signal and the PSTN, to the ADSL modem. It is characterized by consisting of a POTS splitter.

1 is a block diagram showing a line switching device according to the present invention.

2 is a block diagram illustrating a subscriber service request interface device of an asymmetric digital subscriber line system according to the present invention.

Explanation of symbols on the main parts of the drawings

1: Cell bus interface unit 2: ATM multiplexer / demultiplexer unit

3: ATM handler 4: ADSL framer / interface part

5: control unit & DSP unit 6: fresh memory unit

7: DMT processing unit 8: N x M switching unit

9: off-hook interface & switching control unit

10: AFE & off-hook detection section 11: Line driver / receiving section

12: hybrid transform unit 13: CPU

1a: line interface section 2a: digital off-hook detection section

3a: Digital Off Hook Interface & Switching Controls

4a: N x M switching part 5a: Modulation & control part

100: ATM interface unit 200: DMT & control unit

300: line switching processing unit 400: ADSL interface unit

500: POTS Splitter

Hereinafter, a configuration and operation of a subscriber service request interface device of an asymmetric digital subscriber line system according to the present invention will be described with reference to the accompanying drawings.

1 is a block diagram illustrating a line switching device according to the present invention, in which a digital off hook detection unit detects a digital off hook in order to detect a state of a line by applying a dial-up signal to an upstream signal from a long distance ADSL modem ( 2a) and control the N × M switching unit 4a to connect the line requesting service by receiving a digital off hook when the user requests the service, and the unused line puts the physical line except the connection session into the idle state. When there is no traffic in the service line for a long time, when the service request comes in from another line, the digital off-hook interface & switching controller 3a switches to that line and the digital off-hook interface & switching controller 3a. Controls up to six line interface units 1a to one modulation & control unit 5a by control. It is composed of N x M switching unit (4a) to be referred to.

2 is a block diagram illustrating a subscriber service request interface device of an asymmetric digital subscriber line system according to the present invention, which is an ATM interface unit 100, a DMT & control unit 200, a line switching processing unit 300, and an ADSL interface. The unit 400 and the POTS splitter 500.

In more detail, the AMT interface unit 100 multiplexes ATM data from the cell bus interface unit 1 and the cell bus interface unit 1 or the ATM handler 3 to interface with the subscriber multiplexer and the cell bus. Or ATM multiplexer / demultiplexer (2) for demultiplexing, and bidirectional ATM interface for ADSL modems of various data rates, and header translation to separate fast and interleaved signals, respectively. It consists of an ATM handler 3 that performs head error correction, scrambling, and the like.

The DMT & controller 200 performs bit stuffing / robbing elastic store operations, configures an ADSL frame, and then uses a cyclic redundancy (CRC) and forward error correction. message protocol format by interfacing with the ADSL primer / interface unit 4, which constitutes an ADSL superframe by correction and interleaving, and the management entity with the CPU 13 control & DSP unit for controlling the ADSL primer / interface unit 4, the DMT processing unit 7, and the analog front end (AFE) & off-hook detection unit 10 under the control of the CPU 13 while communicating in a format). (5), and a fresh memory section 6 for initializing the system by downloading the program memory from the program memory of the CPU clock, and for storing instruction opcodes and data values; Downward AD A DMT processor (7) that receives a SL superframe signal and performs QAM, IFFT (inverse fast fourir tarnsform), and digital filter functions, and receives an uplink ADSL signal to perform digital filter, fast fourir transform (FFT), and QAM demodulation (7). It consists of.

In addition, the line switching processing unit 300 includes an NxM switching unit 8 for switching six ADSL line interface units 200 per line of downlink data signal under the control of the off-hook interface unit & switching control unit 9 and subscribers. It detects the status of the line and connects the subscriber line to the network when the subscriber wants to connect.When the subscriber line is in the idle state, the protocol session is kept live, but the physical connection is It consists of an off hook interface & switching control part 9 which functions to turn off.

Finally, the ADSL line interface unit 400 converts the downlink DMT signal into an analog signal, then 99KHz high pass filtering, 4MHz low pass filtering, and low pass filtering the downlink analog DMT signal. AFE & off-hook detection unit 10 for converting to digital signals and detecting digital off-hooks from each line, and amplifying the down analog DMT signal and receiving the down analog DMT signal to perform 99KHz low pass filtering and 34KHz high pass filtering. A hybrid driver 12 for converting the line driver / receiver 11 and the downlink 4-wire signal into a 2-wire signal while converting the uplink 2-wire signal into a 4-wire signal and performing line impedance matching. It consists of.

The operation of the present invention configured as described above will be described.

Prior to the description of the overall operation of the present invention, since the present invention was implemented using the line switching device as shown in FIG. 1, the line switching device will be briefly described.

Dial-up signaling is applied to an uplink signal from a long distance ADSL modem through the line interface unit 1a to carry a digital off hook to detect the state of the line. When the user requests a service, the hook detection unit 2a detects this signal and sends it to the digital off hook interface & switching control unit 3a.

The digital off-hook interface & switching control section 3a receives this signal and controls the N × M switching section 4a to connect a line requesting service, and the unused line idles the physical line except the connection session. It is in the idle state when traffic is not made for a long time in the service line. In addition, when there is no traffic for a short period of time on a service line, when a service request comes in on another line, it switches to that line.

In particular, the apparatus is configured to switch up to six line interface units 1a to one modulation & control unit 5a.

Next, the operation of the present invention to which the line switching device is applied will be described.

The cell bus interface unit 1 for interfacing the subscriber multiplexer with the cell bus receives the ATM cell data from the upper Internet server or the video server via the cell bus, thereby providing an ATM multiplexer. The demultiplexer section 2 is transmitted.

The ATM multiplexer / demultiplexer section 2 which demultiplexes the ATM data coming from the cell bus interface section 1 or multiplexes the ATM data coming from the ATM handler 3 has four subscribers' ATMs coming from the cell bus interface section 1. The multiplexed signal is demultiplexed and transmitted to the four ATM handlers 3, or the ATM data of the four subscribers from the ATM handler 3 is multiplexed and sent to the cell bus interface unit 1.

The ATM handler (3), which supports a bi-directional ATM interface for ADSL modems at various data rates, header-translates the data from the ATM multiplexer / demultiplexer section (2) to separate the fast signal and the interleaver signal, respectively, and the head error connection. And scrambling and sending the data to the ADSL framer / interface unit 4 and receiving the fast data and the interleaver data signal from the ADSL framer / interface unit 4, respectively, for cell delineation and descrambling. The header translation is multiplexed into the fast data and the interleaver data, and sent to the ATM multiplexer / demultiplexer unit 2.

In addition, the ADSL framer / interface unit 4 constituting the interface and the ADSL superframe with the ATM handler 3 receives the data from the ATM handler 3 so as to configure the ADSL frame. After the store operation, the ADSL frame and the ADSL superframe are configured, the CRC, the forward error connection, and the interleaving are transmitted to the DMT processing unit 7, and the data signal from the DMT processing unit 7 is received and transmitted in reverse.

And a control & DSP unit for interfacing with the CPU 13 to control the ADSL primer / interface unit 4, the DMT processing unit 7, the AFE & off-hook detection unit 10, and to perform digital signal processing. 5) interfaced with the management entity of the CPU 13 and communicated in a message protocol format, and under the control of the CPU 13, the ADSL primer / interface unit 4, the DMT processing unit 7, and the AFE & off hook detection unit. The control unit 10 controls the echo congestion process of the AFE & off-hook detection unit 10, that is, the digital signal.

The fresh memory unit 6 downloads and stores a program memory, which downloads and stores an instruction upcode and a data value from the program memory of the CPU 13 clock. Do it.

The DMT processing unit 7 having a discrete multitone processing function receives the ADSL superframe signal from the ADSL framer / interface unit 4, performs QAM, IFFT, and digital filtering to off-hook interface & switching control unit 9 ), And receive the data signal from the off-hook interface & switching control unit 9, and digitally filter, FFT and QAM demodulate it and send it to the ADSL framer / interface unit 4.

The N × M switching unit 8 for switching the ADSL interface unit 400 includes six ADSL interface units 400 per line of data signals coming from the DMT processing unit 7 under the control of the off-hook interface & switching control unit 9. ).

The off-hook interface & switching control unit 9 which detects the state of the subscriber line and controls the N × M switching unit 8 is digital off-hook when the subscriber wants to connect, i.e. by dial-up signaling from a remote ADSL modem. If a subscriber line is detected, the corresponding subscriber line is connected to the network.When the subscriber line is not used, the protocol session is kept live, but the physical connection is kept idle, and the service is activated immediately when a service request comes in. Even if there is no traffic for a certain period of time, it will return to the idle state or switch to service another line.

The AFE & off-hook detection unit 10 converts the DMT digital signal into an analog signal and detects the digital hook-off state of each line, converts the DMT signal from the DMT processing unit 7 into an analog signal, and then filters 99KHz high pass. And 4MHz low pass filtering to the line driver / receiver 11, and low pass filtering the analog DMT signal from the line driver / receiver 11 and converting it into a digital signal to convert the N x M switching unit 8 The digital off-hook is detected from each line and transmitted to the off-hook interface & switching control unit (9).

The line driver / receiver 11, which amplifies the signal to transmit the two lines, amplifies an analog DMT signal from the AFE & off-hook detection unit 10 and transmits the analog DMT signal to the hybrid transform unit 12. 12) receives the analog DMT signal from the 99Khz low pass filtering, while the 34Khz high pass filtering is transmitted to the DMT processing unit 10.

The hybrid transform unit 12 that converts 4-wire into 2-wire converts 4-wire signals from the line driver / receiver 11 into 2-wire signals, and converts 2-wire signals from the POTS splitter 500 into 4-wire signals. The signal is converted and transmitted to the line driver / receiver 11 so that the line impedance is matched.

The POTS splitter 500, which multiplexes the DMT signal and the POTS signal, uses an ADSL modem that uses an ADSL signal obtained by frequency division multiplexing the DMT signal from the hybrid transform unit 12 and the POTS signal, which is an analog telephone signal from a public switched telephone network (PSTN). It receives the ADSL signal from the ADSL modem, separates the DMT signal and the POTS signal, and transmits the DMT signal to the hybrid transform unit 12, while the POTS signal is transmitted to the PSTN exchanger (not shown).

Finally, the CPU 13, which controls the operation of the various configurations described above, manages initialization and control of each line, state monitoring, and state information, and performs network management and interfacing functions together.

As described above, the present invention is less affected by noise than the CAP and QAM schemes, and adopts the ATM transmission scheme to ensure high quality, while accommodating high bandwidth multidata and integrating with other networks. have.

In addition, since one modem device serves 24 subscriber lines, end-to-end service cost can be reduced, and the size of the device can be reduced, and power consumption can be reduced.

Claims (6)

A digital off hook detector (2a) for detecting a digital off hook to detect a state of a line by applying a dial-up signal to an uplink signal coming from an ADSL modem over a long distance; When the user requests a service, the N x M switching unit 4a is controlled to connect a line requesting a service by receiving a digital off-hook, and the unused line puts the physical line except the connection session in an idle state, A digital off-hook interface & switching controller 3a for switching to another line when a service request comes in when there is no traffic for a long time; It is composed of N x M switching part 4a for switching up to six line interface parts 1a to one modulation & control part 5a under the control of the digital off-hook interface & switching control part 3a. Line switching device characterized in that. ATM interface unit for multiplexing / demultiplexing data transmitted between subscriber multiplexer and DMT & control unit 200, interpreting bidirectional ATM interface to separate fast signal and interleaver signal, and performing each head error connection, scrambling, etc. 100; A DMT & control unit 200 configured to configure an ADSL frame and then configure an ADSL superframe, download a program memory from a program memory of a CPU clock, initialize a system, and store instruction opcodes and data values; A line switching processing unit 300 for detecting a digital off hook of a line detected by a service request by a long distance ADSL modem dial-up and controlling an idle or active state of a subscriber line according to the digital on / off hook; An ADSL line interface 400 for converting a downlink DMT signal into an analog signal or converting a downlink analog DMT signal into a digital signal, receiving a DMT signal, and matching line impedance; Transmits the ADSL signal obtained by frequency division multiplexing the downlink DMT signal and the POTS signal, which is an analog telephone signal from the PSTN, to the ADSL modem, receives the ADSL signal from the ADSL modem, separates the DMT signal and the POTS signal, and divides the DMT signal into the ADSL line interface Subscriber service request interface device of the asymmetric digital subscriber line system, characterized in that consisting of a POTS splitter 500 to transmit to (200). 3. The AMT interface unit (100) according to claim 2, wherein the AMT interface unit (100) is a cell bus interface unit (1) for interfacing with a subscriber multiplexer and a cell bus, and ATM data from the cell bus interface unit (1) or the ATM handler (3). ATM multiplexer / demultiplexer section (2) for multiplexing or demultiplexing the system, and bidirectional ATM interface for ADSL modems with various data rates, and interpreting handlers to separate the fast signal and the interleaver signal, and to separate the head error connection and scrambling. And a subscriber service request interface device of an asymmetric digital subscriber line system, characterized in that it comprises an ATM handler (3). The ADSL framer of claim 2, wherein the DMT & controller 200 configures an ADSL superframe by performing bit stuffing / lobbing & elastic store operations, constructing an ADSL frame, and then performing CRC, forward error correction, and interleaving. / Interface unit 4, the interface between the CPU 13 and the management entity to communicate in the message protocol format, under the control of the CPU 13 ADSL primer / interface unit 4, DMT processing unit 7, A control & DSP unit 5 for controlling the AFE & off hook detection unit 10, and a fresh memory unit 6 for downloading the program memory from the program memory of the CPU clock, initializing the system, and storing instruction opcodes and data values. And a DMT processing unit 7 that receives the downlink ADSL superframe signal to perform QAM, IFFT, and digital filter functions, and receives the uplink ADSL signal to perform digital filter, FFT, and QAM demodulation functions. Asymmetric Digital Subscriber service request interface device of the subscriber line system that features doeeojim. The line switching processing unit (300) according to claim 2, wherein the line switching processing unit (300) switches N x M switching of six ADSL line interface units (200) per line of downlink data signal by the control of the off-hook interface unit & switching control unit (9). Part 8 detects the status of the subscriber line and connects the subscriber line to the network when the subscriber wants to connect. When the subscriber line is idle, the protocol session is kept live but the physical connection is turned off. A subscriber service request interface device for an asymmetric digital subscriber line system, characterized in that it comprises an off-hook interface & switching control unit (9). The ADSL line interface unit 400 converts the downlink DMT signal into an analog signal, and then performs 99KHz high pass filtering, 4MHz low pass filtering, and low pass filtering the downlink analog DMT signal into a digital signal. On the other hand, the AFE & off hook detection unit 10 detects a digital off hook from each line, and a line driver / receiver unit amplifies the down analog DMT signal and receives the down analog DMT signal to filter 99 KHz low pass and 34 KHz high pass (11). And a hybrid transform unit 12 for converting a downward 4-wire signal into a 2-wire signal while converting an upward 2-wire signal into a 4-wire signal and matching line impedance. Subscriber service request interface device.