KR100267373B1 - High-Speed Digital Subscriber Line (VDSL) Modem Eliminating Interference from Up and Down Channels - Google Patents

Abstract

PURPOSE: A VDSL(Very high speed Digital Subscriber Line) modem is provided to insert upward stream control information in downward stream for transmission by a half duplex system for VDSL, and to allow an STB(Set Top Box) so as to analyze downward stream and transmit upward stream when downward data does not exist. CONSTITUTION: A downward stream controller inserts an upward stream control signal, displaying an end of downward data using a user data bit inside a header byte of a framer, in a downward stream, when transmitting the downward stream through a downward stream transmitter(2). An upward stream controller receives the downward stream when the downward stream transmitter(2) completes the transmission of the downward stream. And the upward stream controller analyzes the downward stream to load upward stream right after the downward stream, if the information indicating the end of the downward stream is detected. An upward stream transmitter(8) transmits the upward stream according to control of the upward stream controller.

Description

High-speed Digital Subscriber Line (HDDSL) Modem Eliminating the Effects of Up and Down Channel Interference

The present invention relates to a high speed digital subscriber line (hereinafter referred to as VDSL) modem which removes interference effects of up and down channels, and is transmitted from a VDSL terminal when upstream control information is inserted downstream. VDSL modem technology using a half-duplex transmission that transmits an upstream by analyzing a stream.

In general, the VDSL system transmits the uplink and downlink channels in the same time slot and requires a diplexer for separating the uplink and downlink signals.

Referring to the structure of the conventional VDSL modem, as shown in FIG. 1, a modem connected to the ATM equipment side and a modem connected to the subscriber side are configured to receive an ATM cell from the ATM equipment and to frame the ATM cell. And VDSL primer 1 to perform its dysfunction;

A downstream transmitter (2) for encoding and modulating the byte stream of the frame structure input through the VDSL primer (1) into an equivalent code symbol stream;

An upstream receiver (3) for receiving and demodulating the upstream generated from the subscriber side and delivering it to the VDSL primer (1);

Respective band filters (4, 5) for extracting downlink and uplink signals from the downstream transmitter (2) and the upstream receiver (3);

A diplexer (6) for connecting the downstream transmitter (2) and the upstream receiver (3) to operate with the same antenna;

The subscriber side includes a downstream receiver (7) for receiving the downstream generated from the ATM equipment side;

An upstream transmitter 8 for transmitting an upstream generated at the subscriber side;

A diplexer (9) connected to the downstream receiver (7) and the upstream transmitter (8) so that each transmitter / receiver can be operated through the same antenna;

Respective band filters 10 and 11 for extracting upstream and downstream signals from the downstream receiver 7 and the upstream transmitter 8; And

It is provided with a VDSL primer 12 for receiving and framing ATM cells from the ATM equipment input through the downstream receiver (7).

The VDSL modem configured as described above transmits data in a full duplex manner, and its operation is as follows.

The ATM cell received from the ATM equipment is framed into an A1 frame consisting of a header and a payload in the VDSL framer 1 and sent to the downstream transmitter 2. In this case, the payload is composed of a Code Reed-Solomon Code (RS) code. Each RS code is composed of an ATM byte and a Forward Error Correction (FEC).

A1 frame is received from the TC sublayer, and the received byte stream is encoded into an equivalent modulation symbol stream and modulated into a signal suitable for sending to the interface medium.

The modulated signal is attenuated and shaped by the band filter 4 at a frequency higher than the use frequency, and then transmitted to the subscriber station through the diplexer 6, the protection circuit and the transformer, and then through a transmission medium.

On the contrary, the upstream signal inputted from the subscriber side through the transmission medium is input to the upstream receiver 3 by eliminating the out-of-use frequency band signal through the band pass filter 5.

After demodulating the signal in the upstream receiver 3, frame data is inversely framed to extract ATM frame data and transmitted to the ATM equipment.

Through the subscriber line configured as described above, information between the ATM equipment and the subscriber is transmitted / received.

However, it is very difficult to operate the diplexer and the band pass filter included in the subscriber line in an ideal state.

That is, since there is no ideal diplexer and band filter, interference occurs between upstream and downstream channels.

In order to solve this interference to some extent, a plurality of band filters are used for each transmitter / receiver (one each in the figure is shown) to solve the problem by increasing the filter order. It is economically inefficient because many filters must be used.

Accordingly, there is a need for a new transmission technology to solve the above problem.

In the present invention, in consideration of the conventional requirements as described above, if the VDSL, which is a full duplex, up-down, using a half-duplex method and inserts upstream control information downstream and transmits the set-top-box (hereinafter referred to as STB) Its purpose is to implement VDSL that eliminates interference effects of up and down channels by analyzing downstream and transmitting upstream when there is no downlink data.

1 is a block diagram showing the structure of a typical VDSL modem.

2 is a block diagram showing the structure of a VDSL modem according to the present invention;

<Description of Symbols for Major Parts of Drawings>

1, 12: VDSL primer 2: downstream transmitter

3: upstream receiver 4, 5, 10, 11: band filter

7: downstream receiver 8: upstream transmitter

13: downstream controller 14: upstream controller

In a VDSL modem having a high speed digital subscriber line (VDSL) primer, an up / down transceiver, and a band pass filter for transmitting ATM data in an asynchronous transmission mode network (ATM) to achieve the above object,

A downstream controller for inserting, into the downstream, an upstream control signal indicating a portion where the downstream data ends by using user data bits in the header byte of the primer when transmitting the downstream through the downstream transmitter;

When the downstream transmission is completed in the downstream transmitter, after receiving the downstream through a band pass filter, if the information indicating that the end of the downstream is detected by analyzing the downstream, the upstream immediately after the portion, the downstream data An upstream controller for controlling upstream transmission when there is no error; And

And an upstream transmitter for transmitting under the control of the upstream controller.

The above objects, features, and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a VDSL block diagram implemented by the present invention, comprising a modem connected to the ATM equipment side and a modem connected to the subscriber side. The ATM equipment side receives the ATM cell from the ATM equipment and frames the ATM cell. Performing VDSL primer 1;

A downstream transmitter (2) for encoding and modulating the byte stream of the frame structure input through the VDSL primer (1) into an equivalent code symbol stream;

A downstream controller 13 for indicating a portion where the downstream data ends by using the user data bits in the header byte of the primer when transmitting the downstream through the downstream transmitter 2;

An upstream receiver (3) for receiving, demodulating and forwarding the upstream transmitted from the subscriber side to the framer (1);

A respective band filter (4, 5) for extracting downlink and uplink signals from the downstream transmitter (2) and the upstream receiver (3);

The subscriber side includes a downstream receiver (7) for receiving the downstream transmitted from the ATM equipment;

An upstream controller (14) which analyzes the downstream stream inputted from the downstream receiver (7) and controls to carry the upstream immediately after the control information indicating the end of the downstream stream is inserted;

An upstream transmitter 8 for transmitting upstream to ATM equipment under the control of the upstream controller 14;

Respective band filters 10 and 11 for extracting upstream and downstream signals from the downstream receiver 7 and the upstream transmitter 8; And

A VDSL primer 12 is provided to frame the ATM cell inputted through the downstream receiver 7 and perform a reverse function thereof.

An operation process of the VDSL modem configured as described above will be described. In this case, only the operation part of each stream controller 13 and 14 will be described without the operation process of the same part as in the prior art.

As in the prior art, since the payload transmission method, which is a transmission method when transmitting and receiving data through up and down transmitters and receivers, is ATM, control of upstream and downstream streams is possible through a buffer in the framer.

In addition, the amount of upstream information is small.

Therefore, when transmitting downstream from the ATM equipment to the subscriber side, the downstream controller 13 inserts and transmits an upstream control signal indicating that the downstream data ends in the user data bit portion of the header byte of the primer.

When the downstream including the upstream control signal is input to the downstream receiver 7 on the subscriber side, it is transmitted to the VSDL primer 12 and the VDSL primer 12 analyzes the downstream to analyze the downstream data. Immediately to the end of the upstream stream to be transmitted.

Its control is carried out via the upstream controller 14, where downstream transmission is interrupted.

That is, the present invention is a half-duplex transmission method in which uplink data is transmitted when there is no downlink data.

In the present invention, since the half-duplex method is used for the downlink and uplink data transmission, since the interference between the downlink and the uplink bands does not occur, the filtering order can be reduced, and only one filter for distinguishing the downlink and the uplink is provided. do.

As described in detail above, the present invention has the advantage of eliminating mutual interference during uplink / downlink channel transmission using the full-duplex VDSL modem method using the half-duplex method. In addition, because the order of the filter is reduced, the manufacturing cost of the band pass filter is reduced, which brings economic advantages.

In addition, a preferred embodiment of the present invention is disclosed for the purpose of illustration, those skilled in the art will be able to make various modifications, changes, additions, etc. within the spirit and scope of the present invention, such modifications and modifications belong to the following claims You will have to look.

Claims (3)

In a VDSL modem having a high speed digital subscriber line (VDSL) primer, an up / down transceiver and a band pass filter for transmitting ATM data in an asynchronous transmission mode network (ATM), A downstream controller for inserting, into the downstream, an upstream control signal indicating a portion where the downstream data ends by using user data bits in a header byte of a framer when transmitting the downstream through the downstream transmitter; When the downstream transmission is completed in the downstream transmitter, after receiving the downstream through a band pass filter, if the information indicating that the end of the downstream is detected by analyzing the downstream, the upstream immediately after the portion, the downstream data An upstream controller for controlling upstream transmission when there is no error; And And an upstream transmitter for transmitting an upstream stream under the control of the upstream controller. 2. The method of claim 1, Under the control of the upstream controller, when the upstream is transmitted at the end of the downstream, the downlink transmission is stopped using a half-duplex transmission method. High-speed digital subscriber line (VDSL) modem that eliminates the effects of interference. The method of claim 1, Since the band filter has no up and down interference, only one for up / down band separation is used for each transmitter / receiver stage, thereby eliminating the interference effect of the VDSL up and down channels. High speed digital subscriber line (VDSL) modem removed.

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