KR20030055567A - method for controlling a handshaking of xDSL system - Google Patents

Abstract

PURPOSE: A method for controlling handshaking of an xDSL system is provided to variably transmit an echo signal transceived through an EOC(Embedded Operation Channel) of a frame, thereby considerably reducing load of the xDSL system. CONSTITUTION: An xDSL system is drive by a default setting value(S2) in an initial state(S1). The system transmits a testing signal of checking whether a current transmission path state is good(S3), and decides whether the transmission path state is good(S4). If so, the system transmits a message signal for handshaking with variable transmission frequency(S6), and sets an optimal transmission speed and continuously checks the transmission path state(S7). The system decides whether characteristics of a current transmission path are frequently changed(S8). If not, the system makes a transmission period of an information collecting message signal shorter than a preset general period, and collects transmission path environmental information(S10). The system determines an optimal transmission method(S11).

Description

Method for controlling a handshaking of xDSL system

The present invention relates to a method for controlling handshaking of an X-DSL system, and in particular, an X-DX for variably transmitting an echo signal transmitted and received through an EOC channel of a frame according to the state of a transmission line in order to find an optimal condition in the handshaking of an xDSL system. A handshaking control method of SL system.

In general, as the industrial society is developed into an information society, efforts are being made to share various information quickly and in large quantities among media. In particular, in the 1990s, technologically advanced countries have been competing to establish high-speed information and communication networks.In order to construct such high-speed information and communication networks, the broadcasting business is based on CATV network, the data and computer industry is based on internet, and the telecommunication business is The approach is based on the telephone network. In addition, among the methods for realizing such a high-speed information communication network, FTHH (fiber to the home) and ADSL (Asymmetric Digital Subscriber Line) methods are widely used.

However, the system based on the ASL (Asymmetric Digital Subscriber Line) is a high-speed digital service, for example, high-speed at the same time without interfering with the analog telephone service (POTS) on the existing twisted pair copper network that the subscriber network is configured It refers to a service system provided to telephone subscribers such as the Internet, online access, telecommuting, and VODIO ON DEMAND. In general, the ADSL line coding scheme uses discrete multi-tone (DMT) and carrierless AM / PM (CAP) scheme, and this ADSL DMT has 64-640 kbit / s when the asymmetric bandwidth characteristic is upstream. For downstream, it supports 8 Mbit / s at 500 kbit / s. Therefore, such an ADSL system has a characteristic of downloading a large file containing graphics from a medium such as the Internet, and a device called a DSLAM (xDSL Access Multiplexer) is usually used to execute the Internet.

Then, referring to the xDSL system using the conventional DSLAM equipment as described above with reference to Figure 1, Pots splitter 71A-71B (PoTSsplitter) for interfacing the subscriber and the communication medium through a communication line (70, copper pair), and An ADSL modem card 72 for modulating / demodulating communication signals input and output from the pots splitters 71A and 71B, and a data processing unit that is a management entity connected to the ADSL modem card 72 to process data call signals ( 73).

Here, the ATM switch 76 is connected to the DSLAM system 74 through an optical cable 75 to interface a communication signal to a medium such as a service medium, for example, the Internet (not shown) or a communication server (not shown). Etc. are provided.

In addition, the subscriber equipment 79, commonly referred to as CPE, includes a pot splitter 71B for interfacing communication signals through a communication line 70 with a DSLAM system 74, commonly referred to as a central office (CO), and the pots. The ADSL modem 77 converts and demodulates a communication signal input and output through the splitter 71B, and the subscriber device unit 78 performs a data processing function through the ADSL modem 77.

Then, referring to the operation of the conventional xDSL system, first, a function called handshaking is performed between the DSLAM system 74, which is CO, and the subscriber equipment 79, which is CPE, to optimally execute data transmission. In this case, the handshaking message transmitted between the two handshaking process is transmitted through the EOC (embedded operation channel) included in the frame shown in FIG. In addition, the shaking message as described above is used when transmitting a command from the CO 74 to the CPE 79, transmitting the information of the CO 74 to the CPE 79, or requesting the information of the CPE 79. .

Here, in the frame structure, the synch byte is a signal area used for synchronizing at the receiving side, the payload is an area used for transmitting higher protocol data to a substantial data area, and the forward error correction (FEC) is an error. This area is used for correction.

Then, in order to perform the shaking process, first, the data processing unit 73 of the DSLAM system 74 modulates the shaking message through the ADSL modem card 72 and transmits it to each subscriber device 79. At this time, the ADSL modem card 72 loads a shaking message inputted from the data processing unit 73, for example, an operation code, to the eoc, and the subscriber equipment 79 which is a CPE through the communication line with the pot splitters 71A and 71B. Is transmitted to the ADSL modem 77). Then, the ADSL modem 77 of the subscriber equipment 79 demodulates the received shaking message and inputs it to the subscriber device unit 78. Accordingly, the subscriber device unit 78 analyzes the operation code included in the input frame signal and loads the same operation code on the eoc of the frame signal and transmits the same operation code back to the CO 74 as an echo signal.

At this time, between the DSLAM system 74 and the subscriber equipment (79) after transmitting the echo signal of the above-described method about three times irrespective of the transmission conditions of the communication path 70, the optimum transmission condition is confirmed and the original Perform data transfer. For example, if the user of the subscriber equipment 79 wants to access the Internet site through his subscriber device unit 78, the Internet access signal is modulated by the ADSL modem 77 of the subscriber equipment 79 and then ported. The data is transmitted to the DSLAM system 74 through the splitter 71A-B and the communication line 70. Then, the data processing unit 73 of the DSLAM system 74 demodulates the received Internet access signal of the subscriber equipment 79 through the ADSL modem card 72 and then transmits it to the ATM switch 76. In addition, the ATM switch 76 connects to the corresponding Internet server (not shown) according to the received Internet access signal, and transmits necessary menu information to the subscriber equipment 79 through the process opposite to the above process. Run

However, in the method of transmitting the handshaking message of the conventional xDSL system, the normal data transmission is performed after transmitting and receiving the echo signals three times in the same manner regardless of the state of the transmission line between the CO 74 and the CPE 79. Therefore, when the transmission line is in good condition, the echo signals need to be continuously transmitted and received unnecessarily, thus causing a problem of significantly increasing the load load of the xDSL system.

Accordingly, the present invention has been invented to solve the conventional problems as described above, by varying the transmission of the echo signal transmitted and received through the EOC channel of the frame in accordance with the state of the transmission line in order to find the optimal condition during handshaking of the xDSL system Therefore, the purpose of the present invention is to provide a handshaking control method of the XLS system which significantly reduces the load of the xDSL system since the number of times the echo signal is repeatedly transmitted unnecessarily regardless of the conditions of the transmission line.

Another object of the present invention is to provide a method for controlling handshaking of an X-DSL system by varying a transmission period of an echo signal so as to properly correspond to a surrounding environment of a transmission path, thereby significantly improving the adaptability of an xDSL system.

In order to achieve the above object, the present invention provides a default driving step in which an xDSL system and a subscriber equipment connect lines with default setting values when a system is first set up in an xDSL system, and an optimum transmission speed after the default driving step. A transmission path checking signal transmitting step of transmitting a testing signal for checking whether the current transmission path condition is good to obtain a signal, and confirming that the current transmission path status is good after the transmission path checking signal transmission step. A variable transmission step of transmitting an echo signal for handshaking at a variable transmission frequency suitable for the transmission, and using the information collected by the handshaking process after the variable transmission step, the optimum transmission speed is set to the corresponding transmission system and transmitted. Optimum speed setting step of continuously checking the state of the furnace, and transmission path characteristics after the optimum speed setting step A method for controlling handshaking of an X-DSL system comprising a step of maintaining an optimal transmission path for varying a transmission period of an information collection message by continuously checking the rate of change of the information and resetting the transmission method using the collected information.

1 is a block diagram illustrating a conventional xDSL system.

2 is an explanatory diagram for explaining a frame structure of an echo signal transmitted during handshaking of an xDSL system;

3 is an explanatory diagram illustrating an example of an xDSL system to which the method of the present invention is applied.

4 is an explanatory diagram illustrating a subscriber board of the xDSL system of FIG. 3;

5 is a flowchart of the present invention.

<Detailed Description of Codes>

1A-N: Subscriber Equipment 2: Communication Line

3: ADSL Modem Card 4: xDSL System

5: control board 6A-N: subscriber board

7 interface unit 8 signal conversion unit

9: data signal processing section 10: memory section

11: control unit 12: signal interface unit

13: ADSL modem 14: subscriber unit

15: optical cable 16: communication server

17: ATM Switch

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The xDSL system to which the present invention is applied is an ADSL modem card (3) for modulating / demodulating a communication signal input / output to and from the outside through the communication line (2) and the plurality of subscriber equipments (1A-N) as shown in FIG. And a control board 5 for overall control of the functions of the xDSL system 4, including the echo variable transmission function of the subscriber equipment 1A-N, and the ADSL communication with the control board 5. And a plurality of ADSL subscriber boards 6A-N for transmitting subscriber information.

In addition, the ADSL subscriber board 6A-N is connected to the subscriber equipment 1A-N as shown in FIG. 4, and has an interface unit 7 for a signal interface, and is input and output through the interface unit 7. A signal converter 8 for converting a communication signal into A (analog) / D (digital) or D / A, and a data signal processor 9 for data signal processing a communication signal via the signal converter 8; And a memory unit 10 for storing subscriber related information processed by the data signal processing unit 9 and an input / output function of subscriber related information stored in the memory unit 10, and the ADSL subscriber board. The control part 11 which controls the function of 6A-N as a whole is included.

In addition, the subscriber equipment 1A-N commonly referred to as CPE has a signal interface unit 12 for interfacing communication signals through an xDSL system 4 commonly referred to as a central office (C) and a communication line (2), and the signal. The ADSL modem 13 converts / demodulates a communication signal input and output through the interface unit 12, and the subscriber device unit 14 performing a data processing function through the ADSL modem 13.

Here, the xDSL system 4 is typically connected via an optical cable 15 to an ATM switch 17 for interfacing communication signals to a medium such as a service medium, for example, the Internet or the communication server 16.

The following describes the method of the present invention applied to the xDSL system as described above.

The present invention proceeds from the initial state (S1) to the default drive step (S2) as shown in Figure 5 when the system is first set up, xDSL system and subscriber equipment connects the line to the default setting value. After the default driving step (S2), the process proceeds to the transmission path checking signal transmission step (S3) to transmit a testing signal for checking whether the current transmission path condition is good to obtain an optimal transmission speed. After the transmission path state checking signal transmission step S3, the transmission path state determination step S4 is performed to determine whether the current transmission path state is good. At this time, if it is determined during the transmission path state determination step (S4) that the current transmission path state is not good, proceed to the general transmission step (S5) to set the message signal for handshaking through the current transmission path to the set normal number of times. send. However, if the current transmission path state is good as a result of the determination during the transmission path state determination step (S4), proceed to the variable transmission step (S6) to generate a message signal for handshaking at a variable transmission frequency suitable for the current transmission path state. send. After the variable transmission step (S6), the process proceeds to the optimum speed setting step (S7), by using the information collected by the handshaking process, by setting the optimum transmission speed to the corresponding transmission system, and continuously checking the transmission path state. do.

On the other hand, after the optimum speed setting step (S7) proceeds to the transmission path characteristic change determination step (S8) to determine whether the current transmission path characteristics change frequently. At this time, if the current transmission path characteristics change frequently as a result of the determination in the transmission path characteristic change determination step (S8), proceed to the general transmission cycle execution step (S9) to transmit the transmission period of the information collection message signal at a predetermined general period. To collect environmental information. However, if the current transmission path characteristics do not change frequently as a result of the determination during the transmission characteristic change determination step (S8), the process proceeds to the variable transmission period execution step (S10), where the transmission period of the information collection message signal is set to a predetermined general period. Make it shorter to collect the environmental information of the transmission line. After the variable transmission cycle execution step (S10), the transmission path setting information change step (S11) is performed to determine and apply an optimal transmission method using the currently collected transmission path environment information.

In other words, when the xDSL system 4 is first set up, the control board 5 starts driving with each subscriber equipment 1A-N and a default setting. In this case, the default setting values include modulation, error correction, frequency, etc., and these default setting values are methods for attaching transmission paths at a minimum rate.

In this case, when the transmission path is connected through the default setting process, the handshaking process is performed to obtain an optimal transmission speed. In this case, the control board 5 first of all, the ADSL modem card 3 and the respective subscriber boards ( 6A-N) transmits a handshaking message signal to each subscriber equipment 1A-N through the EOC channel of the frame shown in FIG.

Then, the signal interface unit 12 of each subscriber station 1A-N interfaces the input handshaking message signal and outputs it to the ADSL modem 13. Then, the ADSL modem 13 of the subscriber equipment 1A-N demodulates the input handshaking message signal and inputs it to the subscriber device unit 14. Then, the subscriber device unit 14 of the subscriber equipment 1A-N analyzes the input handshaking message and loads the echo signal corresponding to the EOC channel to demodulate it through the ADSL modem 13 and then the signal interface unit ( 12) and through the communication line (2) to the subscriber board (6A-N).

The interface unit 7 of the subscriber board 6A-N interfaces the echo signals received from the subscriber equipment 1A-N and inputs them to the signal converter 8. Then, the signal conversion unit 8 converts the analog echo signal input from the interface unit 7 into a digital signal according to the function control signal of the control unit 11 and inputs it to the data signal processing unit 9. The data signal processor 9 inputs an echo signal of the inputted subscriber equipment 1A-N to the ADSL modem card 3 by processing the data signal, wherein the controller 11 receives the data signal processor ( The subscriber-related information processed by the data signal by 9) is stored in the memory unit 10.

In addition, the ADSL modem card 3 demodulates the echo signals of the subscriber equipment 1A-N input to the control board 5. Then, the control board 5 uses the echo signal received from the current subscriber equipment 1A-N to determine the state of the current transmission line 2, for example, the attenuation of the transmission line or the signal to noise. The state of the transmission line 2 is determined using information such as ratio). In this case, when the state of the transmission line is not good in the determination process, the control board 5 normally transmits the handshaking message by the set number of transmissions when the number of transmissions of the normally set handshaking message is three times. Receive a corresponding echo signal from the subscriber equipment 1A-N. However, when the state of the current transmission line 2 is satisfactory, the control board 5 executes the transmission less than the transmission frequency of the normally set handshaking message and receives the response echo signal accordingly.

Accordingly, the control board 5 finds a setting value capable of achieving an optimal transmission rate by using the information obtained by the handshaking method as described above, and then applies the optimum transmission rate setting value to the xDSL system 4. In addition, it is transmitted to subscriber equipment (1A-N) and applied.

Here, the control board 5 may also vary the number of transmissions depending on the nature of the operation code included in the handshaking message.

For example, if the error rate of the transmission line 2 is high, assuming that the set number of transmissions is three, the control board 5 transmits the set number 3 as it is, while the error rate of the transmission line 2 is If good, if the information transmitted between the xDSL system 4 and the subscriber equipment 1A-N is sensitive information, the handshaking message is transmitted twice or between the xDSL system 4 and the subscriber equipment 1A-N. If the information is not sensitive, the handshaking message is changed only once and handshaking is performed.

Then, the transmission load is considerably reduced as compared to when handshaking regardless of the state of the transmission line as in the prior art.

On the other hand, after connecting the transmission path at the optimal transmission speed through the handshaking process as described above, the control board 5 of the xDSL system 4 also collects and transmits information from the subscriber equipment 1A-N. When the condition of the furnace is monitored, if the condition of the transmission path becomes bad or improves, the transmission path is monitored with different settings.

That is, the control board 5 checks the degree of change in the surrounding environment of the transmission line 2, for example, the change of the error rate of the transmission line is severe for a predetermined time, and then adjusts the transmission period of the echo signal by adjusting the change. There is a number.

For example, the control board 5 may shorten the transmission period of the EOC message when the change of the transmission line 2 is not severe, while transmitting the EOC message when the change of the transmission line 2 is severe. By lengthening the period, the transmission period of the EOC message is adjusted to suit the transmission line.

Herein, the information exchanged with the subscriber equipment 1A-N after the transmission path is connected to the handshaking process and the optimal state as described above may include Modem chip vendor ID, down stream SNR, up stream SNR, RX power, TX power, There is information about down stream pre FEC ERROR, down stream post FEC ERROR, forward error correction method, modulation method, etc.

On the other hand, after connecting the optimal transmission speed and transmission path through the handshaking process and the channel change checking process as described above, the xDSL system 4 continuously collects the change rate through the subscribers 1A-N and EOC information. To update the proper setting value and execute the original data transfer. For example, if the user of the subscriber equipment 1A-N wants to access the Internet site through his subscriber device unit 14, this Internet connection signal is sent to the ADSL modem 13 of the subscriber equipment 1A-N. It is modulated by the signal interface unit 12 and transmitted to the corresponding subscriber board 6A-N of the xDSL system 4 through the communication line 2. Then, the control board 5 of the xDSL system 4 demodulates the Internet access signal of the subscriber equipment 1A-N received by the subscriber board 6A-N through the ADSL modem card 3 and then the optical cable. Transfer to the ATM switch 17 via the (15). In addition, the ATM switch 17 connects to the corresponding Internet server 16 according to the received Internet access signal and transmits necessary menu information to the subscriber equipment 1A-N via the process opposite to the above process. Execute communication.

As described above, the present invention variably transmits an echo signal transmitted / received through the EOC channel of a frame according to the state of a transmission line to find an optimal condition during handshaking of an xDSL system, regardless of the conditions of the transmission line. Since the number of echo signals is repeatedly transmitted, the load of the xDSL system is significantly reduced.

In addition, according to the present invention, since the transmission period of the echo signal is varied so as to correspond appropriately to the surrounding environment of the transmission path, the adaptability of the xDSL system is also significantly improved.

Claims (2)

When the system is first set up in the xDSL system, the default driving step in which the xDSL system and the subscriber equipment connect the lines to the default setting values, and whether the current transmission line condition is good to obtain the optimum transmission speed after the default driving step. A transmission line state checking signal transmission step for transmitting a testing signal for checking, a transmission line state checking step for confirming whether a current transmission path state is good after the transmission line state checking signal transmission step, and the transmission line state checking step If it is confirmed that the transmission line status is not good, the general transmission step of transmitting an echo signal for handshaking through the current transmission line at a set normal number of times, and confirming that the transmission line state is good during the transmission line state checking step. Variable transmission to transmit echo signal for handshaking with variable transmission frequency suitable for transmission line condition And an optimum speed setting step of applying and applying an optimum transmission speed to a corresponding transmission system by using the information collected by the handshaking process after the variable transmission step, and continuing checking the state of the transmission path, and the optimum speed setting step. Later, by checking the rate of change in the characteristics of the transmission path, the transmission cycle of the information collection message is varied, and the optimal transmission path maintenance step is used to reset the transmission method using the collected information. Control method. The method of claim 1, wherein the maintaining of the optimum transmission path comprises: a transmission line characteristic change checking step of continuously checking whether a characteristic of a transmission line frequently changes after an optimum speed setting step; When it is confirmed that the change frequently occurs, the general transmission cycle execution step of transmitting the transmission period of the information collection message in a predetermined general period, and the information collection when it is confirmed that the transmission line characteristics do not change frequently during the transmission characteristic change checking step. A variable transmission cycle execution step of transmitting a message transmission period shorter than a predetermined general period, and a transmission path setting to determine and apply an optimal transmission method using transmission path environment information currently collected after the variable transmission cycle execution step. A handshaking control method of an X-SL system, characterized in that the step of changing information.