KR20010003640A - Circuit and method for preventing cell loss of signal in an atm based mobile telecommunication system - Google Patents

Abstract

PURPOSE: A circuit and a method for preventing a cell loss in a mobile communication system based on ATM (Asynchronous Transfer Mode) are provided to prevent a cell loss that occurs due to installation and separation of server boards which are built in one backboard. CONSTITUTION: Once boards are installed in a backboard (170), a monitor (140) which monitors the installed boards outputs a low level signal because an edge pin is connected to the ground of the backboard. A counter (120) counts a frame pulse of 125 microseconds generated by a frequency generator (110) 32000 times in response to the output of low level signal. If a counting value reaches a predetermined value, 32000, the counter (120) outputs a counting completion signal of low level to a buffer controller (130). The buffer controller (130) outputs a buffer enable signal to enable input/output buffers (160,150) according to the counting completion signal. Based upon the buffer enable signal, data (or cells) are normally transmitted and received between the backboard (170) and the input/output buffers (160,150). As the output of the buffer controller (130) are full up by resistances (181,182) at ordinary times, enable terminals of the input/output buffers (160,150) are disabled though a power is applied to a board. Therefore, even though invalid data are transmitted to the backboard (170), it can be avoided that the data influence the other boards, and the enable terminal of the input buffer (160) is controlled lest a signal from the backboard (170) should be inputted to a board as well. Consequently, the input/output buffers are controlled not to effect signals set up in the existing boards so that error and loss of data may be prevented. In addition, data loss can be prevented in the case of that boards are only installed in the backboard (170) within a board installation delay time set up beforehand.

Description

Cell loss prevention circuit and method in asynchronous transmission mode based mobile communication system {CIRCUIT AND METHOD FOR PREVENTING CELL LOSS OF SIGNAL IN AN ATM BASED MOBILE TELECOMMUNICATION SYSTEM}

The present invention relates to a mobile communication system, and more particularly to prevent cell loss that may occur when the boards are mounted on a back board in an Asynchronous Transfer Mode (ATM) based mobile communication system in which a plurality of boards are mounted on a single back board. It relates to a circuit and a method.

A mobile communication system such as an IMT-2000 system using a code division multiple access (CDMA) scheme is based on an asynchronous transfer mode (ATM) scheme. In the case of transmitting / receiving a cell according to such an ATM method (hereinafter referred to as an “ATM cell”), a UTOPIA (Universal Test & Operations PHY Interface for ATM) protocol is generally used. The mobile communication system is generally configured in such a manner that a plurality of boards are connected to one back board. The boards connected in this way use a data bus, an address bus, and various control signals in common.

Meanwhile, a new board may be mounted while the mobile communication system is in operation, and a board previously used may be mounted. Transmitting and receiving cells when a new board needs to be mounted while a board already mounted on a backboard that uses signals according to the UTOPIA protocol (hereinafter referred to as a "UTOPIA signal") is transmitting and receiving valid cells with another board. The new board needs to be mounted without affecting the board you are working on. In addition, other existing boards need to be dismounted without affecting the board transmitting and receiving valid cells. That is, even when the board is mounted or dismounted, the board transmitting and receiving the cell should be able to transmit and receive the cell normally.

Accordingly, an object of the present invention is to provide a circuit and a method for preventing cell loss by mounting a board in an ATM based mobile communication system in which a plurality of boards are mounted on one back board.

Another object of the present invention is to provide a circuit and a method for preventing cell loss by dismounting a board in an ATM based mobile communication system in which a plurality of boards are mounted on one back board.

The present invention for achieving the above object is an ATM-based movement consisting of a board having a common UTOPIA signal and a board having an input and output buffer for inputting a cell from the backboard and outputting a cell to the backboard In the communication system, a cell loss prevention circuit is configured in each board. The board mounting monitor of the cell loss prevention circuit monitors that a board is mounted on the back board. The buffer controller enables the input buffer and the output buffer when a predetermined time has elapsed when the board is monitored by the board mounting monitoring unit so as not to affect a signal of an existing board. It prevents data loss and errors.

1 is a cell loss prevention circuit diagram of an asynchronous transmission mode (ATM) based mobile communication system according to the present invention.

2 is an operation timing diagram of the cell loss prevention circuit shown in FIG.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to intention or custom of a user or a chip designer, and the definitions should be made based on the contents throughout the present specification.

1 is a view showing the configuration of a cell loss prevention circuit according to the present invention. The other components except for the backboard 170 are components included in one board that can be mounted or mounted on the backboard 170. These components are components that are mounted on the backboard 170 even when mounting or dismounting the board so as not to affect other boards that transmit and receive signals.

Referring to FIG. 1, the frequency generator 110 inputs a frame pulse of a preset frequency to generate one pulse in a preset time unit. The frame pulse may have a frequency of 8 kHz and may be provided from an E1 framer. In this case, the frequency generator 110 generates one pulse every 125 μsec.

The counter unit 120 counts the pulses generated by the frequency generator 110 and makes a time for controlling the input buffer 160 and the output buffer 150 when the actual board is mounted. For example, the counter unit 120 may generate a delay time of 4 seconds by counting 32000 pulses generated every 125 μsec. Here, the meaning of 4 seconds is taken into consideration when the board is slowly mounted, and is intended to enable the input buffer 160 and the output buffer 150 at least 4 seconds after mounting the board. That is, the counter unit 120 counts the pulses generated by the frequency generator 110 by a preset number of times, and generates a count completion signal having a "low" level when the count is completed.

The buffer controller 130 opens the buffers 150 and 160 when the counter 120 counts and passes a predetermined time (4 seconds). That is, in response to the count completion signal from the counter 120 being generated, the buffer controller 130 outputs a buffer enable signal having a "low" level for enabling the input buffer 160 and the output buffer 150. In this way, the "low" level signal is provided as the buffer enable signal to the input buffer 160 and the output buffer 150 by pulling up between the buffer controller 130 and the input buffer 160 and between the buffer controller 130 and the output buffer 150. This is because the resistors 181, 182 are provided.

The board mounting monitoring unit 140 detects a time at which the board is mounted when the board is mounted on the back board 170. The board mounting monitoring unit 140 is provided with an edge pin for monitoring the board mounting, and the corresponding back board 170 is grounded. That is, when the board is mounted on the back board 170, the board mounting monitoring pin of the board mounting monitoring unit 140 is connected to the ground of the back board 170. The board mounting monitoring unit 140 is provided with a pull up resistor 183. Therefore, when the board is mounted on the backboard 170, the signal of the "low" level is detected, and the signal of the "low" level indicating the detection result is output to the counter 120 so that the counter 120 starts the counting operation.

The input buffer 160 is for buffering the UTOPIA signal from the back board 170, and the output buffer 150 is for buffering the UTOPIA signal for output to the back board 170. The input buffer 160 and the output buffer 150 are enabled in the active " low " state, and are enabled when the buffer intable signal of the "low" level is applied from the buffer controller 130. The loss of the cell can be prevented by controlling the input buffer 160 and the output buffer 150 provided for input / output of the cell between the board and the back board 170 mounted as described above.

FIG. 2 is a diagram illustrating an operation timing of a cell loss prevention circuit configured as shown in FIG. 1.

Referring to FIG. 2, when the board is mounted on the back board 170 of FIG. 1, the board mounting monitor 140 outputs a "low" level signal as the edge pin of the board mounting monitor 140 is connected to the ground of the back board 170. (Refer to FIG. 2 (a)). In response to the “low” level signal being output, the counter 120 performs an operation of counting 32,000 frame pulses of 125 μsec generated by the frequency generator 110 (see FIG. 2B). When the count value reaches 32000, which is set in advance by the count operation started (4 seconds elapse), the counter unit 120 outputs a count completion signal of the "low" level to the buffer controller 130. Then, in response to the count completion signal being input, the buffer controller 130 outputs a buffer enable signal for enabling the input buffer 160 and the output buffer 150. In this way, the input / output buffers 150 and 160 can normally transmit / receive data (or cells) transmitted and received between the backboard 170 and the buffer enable signal.

Since the output of the buffer controller 130 is normally pulled up by the resistors 181 and 182, the enable terminals of the input buffer 160 and the output buffer 150 are disabled even when power is supplied to the board. Thus, invalid data from the board can be transferred to the backboard 170, preventing it from affecting other boards. In addition, the enable terminal of the input buffer 160 is controlled so that a signal from the back board 170 does not enter the board. Such a feature, that is, the valid data is processed only when the input / output buffers 150 and 160 are enabled after a predetermined time (4 seconds) even when the board is mounted, as shown in FIGS. 2C and 2D. It is. The input / output buffers 150 and 160 are in a high impedance state until they are enabled.

The time for enabling the input buffer 160 and the output buffer 150 from the point at which the board is mounted, that is, the counting setting count of the counter 120 and the time unit of the pulse generated by the frequency generator 110 according to the preferred embodiment of the present invention. It is to be noted that, as defined, their values may change. Although the counter 120 starts counting when the input signal is at the "low" level, the input buffer 160 and the output buffer 150 are enabled. However, these signals are within the scope of the present invention. The level may be changed and used.

As described above, the present invention has an advantage of preventing data loss and error by controlling an input / output buffer when mounting a board so as not to affect a signal of an existing board. In addition, the board mounting delay time is set in advance to prevent data loss when the board is mounted only within the set time. Therefore, even if the board is separated between boards using the UTOPIA signal, the stability of the system can be achieved by not affecting the common signal.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

Claims (14)

In a backboard using a common utopia signal and a cell loss prevention circuit included in each board in an asynchronous transmission mode (ATM) based mobile communication system composed of boards, An input buffer for inputting a cell from the backboard; An output buffer for outputting cells to the backboard; A board mounting monitoring unit for monitoring a board mounted on the back board; And a buffer controller for enabling the input buffer and the output buffer when a predetermined time has elapsed when the board is monitored by the board mounting monitor as being mounted on the back board. The cell loss prevention circuit of claim 1, wherein the set time is 4 seconds. In a backboard using a common utopia signal and a cell prevention circuit included in each board in an asynchronous transmission mode (ATM) based mobile communication system composed of boards, An input buffer for inputting a cell from the backboard; An output buffer for outputting cells to the backboard; A board mounting monitoring unit for monitoring a board mounted on the back board; A counter unit for counting a frame pulse a predetermined number of times when the board is monitored as being mounted on the back board by the board mounting monitoring unit; And a buffer controller for enabling the input buffer and the output buffer when the set number of times has been counted by the counter. 4. The cell loss prevention circuit of claim 3, further comprising a frequency generator configured to input the frame pulse to generate a corresponding frequency. 5. The cell loss prevention circuit according to claim 3 or 4, wherein the frame pulse is generated from an E1 framer. 6. The cell loss prevention circuit of claim 5, wherein the frame pulse has a frequency of 8 kHz. 6. The cell loss prevention circuit according to claim 5, wherein the counter unit counts 32000. 4. The cell loss prevention circuit according to claim 3, further comprising a pull-up resistor connected between the buffer control unit and the input buffer. 4. The cell loss prevention circuit of claim 3, further comprising a pull-up resistor connected between the buffer control unit and the output buffer. 4. The cell loss prevention circuit of claim 3, further comprising a pull-up resistor connected between the back board and the board mounting monitoring unit. In the method of preventing the loss of cells in each board in a single asynchronous communication mode (ATM) based mobile communication system consisting of a single backboard and a common utopia (UTOPIA) signal, Monitoring a board mounted on the back board; Blocking transmission and reception of cells to and from the backboard for a predetermined time when a board is mounted on the backboard. To prevent the loss of cells in each board in an Asynchronous Transfer Mode (ATM) based mobile communication system, which consists of one backboard that uses UTOPIA signals in common, and boards with input and output buffers. In the way, Monitoring a board mounted on the back board; Counting the frame pulse a predetermined number of times when the board is monitored as being mounted on the back board by inputting a frame pulse; And enabling the input buffer and the output buffer when the set number of times is counted. The method of claim 12, wherein the frame pulse has a frequency of 8 kHz. The method of claim 12, wherein the set number of times is 32000.