KR100279804B1 - One-point Multipoint Connection Method in Two-Wire Home Networks for Integrated Telecommunication Networks - Google Patents

Abstract

The present invention relates to a one-to-multipoint access method in a two-wired home network for an integrated telecommunication network, wherein a network terminator and a terminal use a different pulse width pseudo ternary coding technique at a single time at a different time of one bit slot. Occupies the link, and because the propagation delay time of the signals from different terminals are different, the network terminator samples the data when the data of all terminals is stably displayed, and the network terminator signal and the terminal signal have different pulse widths. Therefore, the terminal that attempts to make a new connection while the terminal and the terminal are connected and communicating is characterized in that the terminal detects the signal of the terminal and recovers synchronization even from the asynchronous state. According to the present invention, the ISDN service can be provided using a conventional two-wired home network without additional line expansion, and the protocol defined by the four-wire connection standard is applied, so that most of the system developed in the four-wire system is used as it is. There is an advantage to enable ISDN service in a wired home network.

Description

One-Point Multipoint Connection Method in Two-Wire Home Networks for Integrated Telecommunication Networks

The present invention relates to a one-to-multipoint connection method in a two-wired home network for an integrated telecommunication network.

Integrated Services Digital Network (hereinafter referred to as ISDN) is a digital communication network that provides various services together. In other words, ISDN is a comprehensive service digital communication network that develops voice communication to integrate and provide not only voice but also image and data services. The services targeted for integration are narrowband services of 64 kbps or less, mainly telephony, facsimile, teletex, telemetry, telewriting, and data terminals.

The typical features of ISDN are that the subscriber and the communication network are connected by integrating one line so that various services can be comprehensively provided, and the connection between the subscriber and the communication network is digital.

The reference point to which the terminal and the user network are connected is referred to as 'S', and the reference point to which the user network is connected to the public network is referred to as 'T'. That is, the ISDN terminals of the user are connected to the ISDN through the S / T reference access point, and the signal information between the user-network is transmitted through the D channel.

However, the ISDN known so far is four-wire, and a user with a two-wire home network dedicated to analog telephone service needs to install an additional line in order to introduce the four-wire ISDN. In addition, in the case of inevitably installing additional lines in the existing two-wire home network, the installed lines are exposed on the wall, which damages the aesthetics. 1 is a diagram illustrating a conventional two-wired home network for analog telephone service. As shown in Fig. 1, the conventional two-wire home network uses a two-wire analog line connected to a public switched telephone network (PSTN), and each analog telephone is connected to a two-wire analog line. As shown in Fig. 1, a conventionally installed two-wire analog line is dedicated to analog telephone service, there is no additional line for four-wire ISDN, and it is difficult to add a line.

An object of the present invention is to solve the problems of the prior art as described above, by presenting a specification for one-to-multipoint connection in a two-wired home network for a general information communication network, without the addition of additional line It is to provide ISDN service using wired home network.

Another object of the present invention is to apply the protocol specified in the 4-wire connection standard, to enable ISDN service in a 2-wire home network while using most of the system developed in the 4-wire.

1 is a diagram illustrating a conventional two-wire home network for analog telephone service;

2 is a diagram illustrating pseudo ternary code, which is a line coding scheme for one-to-multipoint connection of a conventional four-wire ISDN;

Figure 3 is a view for explaining the standard of the two-wire home network configuration diagram proposed in the present invention,

4 is an S-connection signal timing diagram in a one-to-multiple point connection method in a two-wire home network according to the present invention;

5 is a timing diagram showing a window of a terminal for synchronization recovery in a one-to-multipoint access method in a two-wire home network according to the present invention;

6 is a flowchart of a network terminator signal detection method using the method as shown in FIG. 5;

7 is a flowchart of a synchronous recovery method by detecting a network terminator signal.

Explanation of symbols on the main parts of the drawings

NT: Network Termination

TE: Terminal Equipment

TA: Terminal Adaptation

In order to achieve the object of the present invention as described above, the one-to-multipoint connection method in a two-wired home network for ISDN according to the present invention, the network terminal and the terminal using a pseudo-triggered coding technique of different pulse widths Occupies a single link at different times of one bit slot, and since the propagation delay times of signals from different terminals are different, the network terminator samples the data at the time when the data of all terminals is stably displayed, and the network terminator signal Since the terminal signal and the terminal signal have different pulse widths, the terminal that attempts to make a new connection while the terminal and the terminal are in communication with each other detects the signal of the network terminal from the asynchronous state and recovers synchronization. .

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

In ISDN service, multiple terminals support one-to-multipoint connection to access common D channel. That is, a plurality of terminals share a single D channel, and can be used as a signal channel or a separate data channel for two B channels by accessing in a standardized manner, thereby allowing two B channels and one D channel to be used for multiple terminals. Flexible assignments to people. Therefore, access control on the D channel is very important for one-to-multipoint access. New connection specifications are needed to support this one-to-multipoint connection in a two-wire home network.

In this specification, the characteristics of the one-to-multipoint connection of a conventional four-wire ISDN will be described first, and a novel method for one-to-multipoint connection in a two-wire home network is proposed.

The line coding method and the D channel access control method for S connection proposed in ITU-T Rec. I.430, S connection standard of 4-wire ISDN are as follows.

2 illustrates a pseudo ternary code, which is a preferred coding scheme for one-to-multipoint access of a conventional four-wire ISDN. As shown in Fig. 2, a pseudo ternary code having a duty ratio of 100% pulse width is used as the preferred code for the S connection of the 4-wire ISDN. In the pseudo ternary code, the binary number '1' is represented by 'no signal', and the binary number '0' is represented by a pulse having a positive or negative sign. The sign of binary '0' is determined to be the opposite of the sign of previous binary '0'. Since the binary number '1' is expressed as no signal, when two or more terminals output data at the same time, the binary number '1' is overridden to the binary number '0'.

For the D-channel access control, each terminal continuously observes the D-channel and starts transmitting its data when the data of the D-channel continues at least n 1 (no signal). Here, 'n' is related to its own priority. The call processing terminal has a value of 8 for high priority and a 9 for low priority, and a packet processing terminal of 10 for high priority and 11 for low priority.

The network terminator NT controls the terminal's D channel access by retransmitting the data of the D channel to the echo bit.

Each terminal transmits its own data and compares the echo bit with the previously sent bit and stops the transmission immediately if it does not match. After transmitting the data of one frame to the end, the priority is decreased by one step (n is increased by 1) so that another terminal can use the D channel. If no more than n signals are observed, the terminal returns its priority to its original value (n is decreased by 1).

In the method for one-point multipoint connection in a two-wired home network according to the present invention, the protocol specified in ITU-T Recommendation I.430, a four-wire S-connection standard as described above, is applied to a two-wired home network as it is. ISDN service is available while using the existing system as it is.

On the other hand, in the present invention, since a two-wire home network is to be used, a network terminal and a plurality of terminals should be connected through one physical link. In order to implement the one-to-multipoint connection through D channel access control while accommodating the protocol as described in I.430, the following points should be considered.

First, each terminal must extract synchronization from the network terminator signal. Therefore, in the case of a 2-wire connection in which the network terminal signal and the terminal signal coexist on a single link, the terminals must distinguish the terminal terminal signal from the other terminal signals even in an asynchronous state and find synchronization from the found network terminal signal.

Second, when several terminals compete for the occupancy of the D channel, a plurality of terminals output data. In this case, the network terminator appears stably in consideration of the propagation delay time caused by the connection distance of the terminals. Sample data at the time point

Third, all network terminators and terminals should keep the output impedance high except for their driving section to minimize the change of line characteristics.

Accordingly, the present invention proposes a method for one-to-multipoint connection in a novel two-wired home network in view of the above points.

In the access method proposed in the present invention, one bit slot is divided into two so that the network terminal and the terminal occupy a single link at different times. Since the network terminal and the terminal occupy a single link, the network terminal and the terminal use different pulse width pseudo ternary coding techniques. Since the network terminator and the terminal use pseudo-triggered codes of different pulse widths, the terminal which tries to make a new connection while the terminal and the terminal are connected and communicates can be synchronized by distinguishing the signal of the network terminator even from the asynchronous state. Can be.

In the connection method proposed in the present invention, since the pseudo ternary code is used as the line code, the D-channel access algorithm of Recommendation I.430 of ITU-T can be used without modification.

Figure 3 describes the standard of the two-wire home network configuration diagram proposed in the present invention.

As shown in FIG. 3, according to the one-to-multipoint access method in the two-wired home network proposed in the present invention, the maximum possible passive bus length is T _RTD which is a total round trip delay (RTD) time. It is limited to satisfy the condition of the following equation (1). Termination resistance (R _T ) of short-range passive bus is 100Ω.

In Equation 1, T is one bit interval, T _{NT and DRV} are pulse widths of network terminator signals, T _{TE and DRV} are pulse widths of terminal signals, and T _G is a guard interval. )to be.

4 is an S-connection signal timing diagram in a one-to-multiple point connection method in a two-wired home network according to the present invention.

As shown in Fig. 4, the network terminator output signal has a pulse width of T _{NT and DRV} , and the terminal output signal has a pulse width of T _{TE and DRV} to occupy a single link at different time periods. In addition, the terminal closest to the network terminator (TE _near ) with respect to the network terminator output signal having a pulse width of T _{NT and DRV} is directly input from the terminal but the terminal farthest from the network terminator. (TE _far ) is input after the delay time of T _RTD / 2. Each terminal outputs a terminal output signal having a pulse width of T _{TE and DRV} after the protection interval T _G with respect to the network terminator signal. The output signal from the terminal (TE _near ), which is also located _near the network terminal, is directly input to the network terminal, and the terminal (TE _far ) farthest from the network terminal is delayed after the delay time of T _RTD / 2. Input to network terminal. At this time, the network terminator should sample the data when the data of all the terminals appear stably. In FIG. 4, data from the terminal TE _near the network terminator and data from the terminal TE _far at the furthest position from the network terminator are shown. Therefore, all terminals are displayed in the T _sampling interval shown in FIG. The data will be stable and you can sample the data at this point.

4 illustrates the sampling of a network terminator signal, a terminal signal, and a plurality of terminal signals that occupy a single link at different time periods.

Hereinafter, each terminal recovers synchronization from the network terminator signal. FIG. 5 is a timing diagram illustrating a window of a terminal for synchronization recovery in the present invention, FIG. 6 is a flowchart of detecting a network terminator signal using a window of the terminal, and FIG. 7 is a flowchart of a synchronization recovery by detecting a network terminator signal of FIG. 6. .

Terminals should be able to recover synchronization correctly by distinguishing network terminator signals from other terminal signals even in an asynchronous state.

First, a terminal introduces a window having a specific width W for searching for a network terminator signal in an asynchronous state.

The terminal determines whether there is a transition from '1' (no signal) to '0' (positive or negative pulse) in the window section for one frame time with its clock (positive edge detection). When the transition is observed, it is determined whether the transition from '0' to '1' occurs again by moving the window by T _{NT, DRV, which} is the pulse width of the network terminal signal (negative edge detection). If there is a transition to the furnace, the network terminator signal is determined. If the above-described detection of the network terminator signal occurs more than the reference number of times during the time corresponding to one frame, the terminal determines that the network terminator signal has been detected. If the network terminal signal has not been detected more than the reference number of times during the time corresponding to one frame, the terminal moves the network terminal signal detection window by Δ and repeats the detection of the network terminal signal.

When the network terminator signal is detected by the above-described method, the terminal is shifted to the quasi-synchronous state and the synchronization is restored by applying a general PLL algorithm.

As described above, in the method for one-to-multipoint connection in a two-wire home network according to the present invention, the network terminator and the terminal occupy a single link at different times using pseudo-pulse ternary coding techniques of different pulses. Do it. When several terminals compete, the network terminator samples the data at the time when all the terminal data is stably displayed, and also because the network terminator signal and the terminal signal have different pulse widths, The connecting terminal can be synchronized by distinguishing the signal of the network terminator even in an asynchronous state. Therefore, according to the present invention, the ISDN service can be provided using a conventional two-wired home network without additional line expansion, and the protocol developed by the four-wire connection standard is applied, so most of the system developed in the four-wire is used as it is. However, there is an advantage to enable ISDN service in 2-wire home network.

Claims (3)

In a one-to-many multipoint access method in a two-wire home network for ISDN, the steps of a network terminator and a terminal occupying a single link at different times of one bit slot using different pulse width pseudo ternary coding techniques (a); (B) sampling the data at a time point at which data of all terminals is stably in consideration of a propagation delay time of signals from a plurality of terminals; And the terminal terminal signal and the terminal signal have different pulse widths, so that the terminal attempting a new connection while the terminal terminal and the terminal are connected and communicating detects the signal of the terminal terminal from the asynchronous state and recovers synchronization. And (c) a method for one-to-multipoint connection in a two-wire home network. 2. The method of claim 1, further comprising the step (d) of the terminal detecting a signal of the network terminator using a window of a specific width in an asynchronous state. 3. The method of claim 2, wherein the step (d) is performed by the terminal to determine whether there is a transition from '1' (no signal) to '0' (positive or negative pulse) within the window period for one frame time at its own clock. A positive edge detection step of determining; A negative edge detecting step of determining whether a transition from '0' to '1' occurs again when the window is moved by T _{NT.DRV, which} is the pulse width of the _{network terminal} signal, when a transition is observed in the positive edge detecting step; Determining a network terminator signal when there is a transition from '0' to '1' in the negative edge detection step; And when the detection of the network terminator signal as described above occurs more than the reference number of times during the time corresponding to one frame, the terminal determines that the network terminator signal has been detected, and detects the network terminator signal more than the reference number of times during the time corresponding to one frame. If not, the terminal comprises moving the window and repeating the determination of the network terminator signal.

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