KR100289581B1 - Alarm display signal cell generator of video subscriber unit in optical termination device of demand dense optical subscriber transmission device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an alarm display signal cell generator of an image subscriber unit in an optical termination device of a demand dense optical subscriber transmission device, the image subscriber unit being mounted in an optical termination device (ONU) of a demand dense optical subscriber transmission device. Used to inform the subscriber of an error condition.

The present invention is a failure detection unit for detecting an error in the clock and optical transmission and reception unit (COTU) of the optical termination device and outputs an error generation signal, a virtual path alarm display signal to be transmitted to the subscriber while the error generation signal is output ( VP-AIS) Timer that counts the generation period of the cell, Active port checker that finds the current subscriber port by investigating each subscriber port of video subscriber unit and outputs active port information, Virtual path according to the output signal of timer A header generation unit for generating a header of the alarm display signal cell, a header error correction bit generator for calculating a header error correction (HEC) bit value of the virtual path alarm display signal cell according to the activation port information, and an activation port information. Payload generation unit for generating payload data of the virtual path alarm display signal cell according to the present invention, and the generated virtual path It is made to display alarm signals Utopia cells (UTOPIA) as part Utopia control signal generator for generating a control signal for transmission through the interface.

Description

A unit to generate Alarm Indication Signal Cells for Video Channel Unit of Optical Network Unit in Fiber Loop Carrier-Curb systems

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for generating an alarm display signal cell of an image subscriber unit in an optical termination device of a demand dense optical subscriber transmission device, and in particular, an optical termination device of a demand loop optical subscriber transmission device (Fiber Loop Carrier-Curb system). A video channel unit (VCU), which is installed in an optical network unit (ONU) and connects a set-top box of a subscriber side with an optical end unit (ONU) to allow each subscriber to receive a video service. The present invention relates to an apparatus for generating an alarm indication signal (AIS) cell and informing each subscriber of a predetermined error state.

1 is a schematic diagram of an optical subscriber network using a demand dense optical subscriber transmitter, wherein the demand dense optical subscriber transmitter includes a host digital terminal 103 and an optical terminator 110-1 to 110-16; ONUs, and the host digital terminals 103 (HDT) and the optical terminators 110-1 to 110-16: ONU are connected through optical paths to perform optical communication.

The demand-intensive optical subscriber transmission device (FLC-C system) is a FTTC (Fiber To The Curb) type service transmission platform, and service providers providing various services such as home shopping, games, movies, etc. And through the host digital terminal 103 (HDT) and the optical termination unit (ONU).

Here, the host digital terminal 103 (HDT), which is a component of the demand-density optical subscriber transmission device, is a device installed in a telephone station, and the DS1 and DS1E signals received from the public telephone network 104 (PSTN) and the ATM switch 102 Asynchronous transfer mode (ATM) -based broadband signals to be transmitted, integrated-multiplexed into the synchronous digital hierarchy, and then optically transmitted to the optical end devices (110-1, 110-16: ONU) as a power station; and Performs its dysfunction.

At this time, the ATM switch 102 is connected to a video server 101 for providing a video service such as VOD (Video On Demand).

On the other hand, the optical termination unit (110-1,110-16: ONU) is installed in a distribution center in a dense residential area such as an apartment complex to service the subscriber signal from the STM-4 class optical signal received from the host digital terminal 103 (HDT) It is a device that separates according to the function provided to each subscriber and the reverse function. A telephone and a set top box 120 are connected to the optical termination devices 110-1 to 110-16: ONU.

FIG. 2 is a block diagram of an optical terminator, which includes a clock and optical transceiver unit 210, a main control unit 220, and a DS1 signal connected to a common transceiver bus 201. The processing unit 230, the video subscriber unit 240 (VCU), the frame unit 250 (Framer) and the like. At this time, the dotted line indicates the upward transmission direction and the solid line indicates the downward transmission direction.

When a signal is sent from the host digital terminal 103 (HDT) to the optical terminators 110-1 to 110-16: ONU as shown in FIG. 2, a virtual path identifier (VPI) assigned to each unit. ) Values are shown in Table 1 below.

Unit VPI (Hex) VCI (Hex) VCI (Hex) Remarks MCCU 10 20 Operation communication cell DS1U 30-37 20 4 Private Line Voice Cell VCU # 1 40-47 Unspecified 3 or 4 Imaging cell VCU # 2 50-57 Unspecified 3 or 4 Imaging cell VCU # 3 60-67 Unspecified 3 or 4 Imaging cell VCU # 4 70-77 Unspecified 3 or 4 Imaging cell VCU # 5 80-87 Unspecified 3 or 4 Imaging cell VCU # 6 90-97 Unspecified 3 or 4 Imaging cell VCU # 7 A0-A7 Unspecified 3 or 4 Imaging cell VCU # 8 B0-B7 Unspecified 3 or 4 Imaging cell FRU C0-C7 20 4 Speech cell

That is, as shown in Table 1, the cells are delivered to the corresponding units according to the values of the virtual path identifier (VPI) and the virtual channel identifier (VCI), as shown in Table 1, and the virtual path identifier (VPI) and virtual channel of the upstream and downstream ATM cells. The value of the identifier (VCI: Virtual Channel Identifier) is the same.

Here, the video subscriber unit 240 (VCU) connects the set top box 120 (STB) with the optical terminators 110-1 to 110-16: ONU so that each subscriber can receive a cable television (CATV) or a video on demand (VOD). ) It is a unit to receive service.

In addition, the clock and optical transmitting / receiving apparatus 210 (COTU) is configured to connect to the host digital terminal (HDT) 103 via a optical path to transmit and receive optical signals and network terminators 110-1 to 110-16: ONU. It provides the clock to each unit.

Referring to the operations of the optical terminators 110-1 to 110-16: ONU, the clock and optical transceiving unit 210 (COTU) is a host digital terminal 103 (HDT) and optical terminators 110-1 to 110-. 16: Receives a signal converted into a virtual path identifier (VPI) value set between ONU), and the video signal is transmitted through the common transmit / receive bus 201 according to each virtual path identifier (VPI) value. The voice signal is transmitted to the VCU, and the voice signal input through the dedicated line is transmitted to the DS1 signal processing unit 230, and the general voice signal is transmitted to the framer unit 250 (FRU).

On the other hand, the operation maintenance cell (OAM cell) related to the audio signal is transferred from the clock and optical transmission / reception unit 210 (COTU) to the main control unit 220 (MCCU), and for the operation maintenance cell related to the video signal. Only the operation maintenance cell of which the value of the virtual channel identifier (VCI) is 3 is sent to the main control unit 220 (MCCU) for processing.

In addition, the operation maintenance cell having the value of the virtual channel identifier (VCI) of 4 is transmitted to the set-top box 120 of the subscriber via the corresponding video subscriber unit 240 (VCU). In addition, the video cells input from the common transmit / receive bus 201 are modulated by the video subscriber unit 240 (VCU) and transmitted to the set top box 120 at a predetermined bit rate. At this time, the uplink signal modulated and transmitted by the subscriber is transmitted to the clock and the optical transceiver 210 (COTU) via the common transceiver bus 201.

The common transmit / receive bus 201 processes both up and down signals in one bus, and each unit performs a cell bus switching operation to access the common transmit / receive bus 201. That is, each unit is assigned a unique address, and the common transmit / receive bus 201 is controlled by the clock and optical transmit / receive unit 210 (COTU) according to a virtual path identifier (VPI) value set according to each unit and a port in the unit. do.

On the other hand, in order to inform the respective subscribers of the state of the optical terminals (110-1 to 110-16: ONU), as described above, a method for generating and sending an operation maintenance cell (OAM cell) is used. Conventionally, for this purpose, a commercial chip performing a separate operation and maintenance function has been used in the video subscriber unit 240 (VCU). However, if it is sufficient to send only simple status information (clock and optical transceiver unit to the video subscriber), using a commercial maintenance chip that contains a lot of unused functions, the video subscriber unit (240: VCU) There was a problem that the production cost of the increase.

Accordingly, the present invention has been made to solve the above problems, it is mounted on the optical termination unit (ONU) of the demand-density optical subscriber transmission device to connect a predetermined set-top box of the subscriber side with the optical termination unit (ONU) As a device, it is used in a video subscriber unit (VCU), which is a device that allows each subscriber to receive video service, and provides a device that generates an alarm indication signal (AIS) cell to inform the subscriber when a system failure occurs and delivers it to the subscriber. There is a purpose.

In order to achieve the above object, in the optical termination device of the demand-dense optical subscriber transmission device according to the present invention, the alarm display signal cell generator of the video subscriber unit is a clock and optical transmission / reception unit of the optical termination device (ONU). A failure occurrence detection unit for detecting that an error has occurred in the COTU and outputting an error generation signal; A timer for counting a generation period of a predetermined virtual path alarm indication signal (VP-AIS) cell to be transmitted to a subscriber while the error occurrence signal is output; An activation port identification unit for investigating each subscriber port of the video subscriber unit, finding an active subscriber port, and outputting activation port information; A header generator configured to generate a predetermined header of the virtual path alarm display signal (VP-AIS) cell according to the output signal of the timer; A header error correction bit generator for calculating a header error correction (HEC) bit value of the virtual path alarm indication signal (VP-AIS) cell according to the activation port information; A payload generator configured to generate payload data of the virtual path alarm display signal (VP-AIS) cell according to the activation port information; And a utopia for generating a predetermined control signal for transmitting a virtual path warning display signal (VP-AIS) cell generated from the header generation unit, the header error correction bit generation unit, and the payload generation unit through a UTOPIA interface. Characterized in that it comprises a control signal generator.

1 is a schematic diagram of an optical subscriber network using a demand dense optical subscriber transmission device;

2 is a block diagram of an optical termination device;

3 is a block diagram of an alarm display signal cell generator according to the present invention;

4 is a timing diagram of generation of an alarm display signal cell;

5 is a flowchart illustrating an operation of an alarm display signal cell generator according to the present invention.

* Explanation of symbols for main parts of the drawings

103: Host Digital Terminal (HDT) 110-1,110-16: Optical Termination Unit (ONU)

120: set-top box 201: common transmit and receive bus

210: Clock and Optical Transceiver Unit (COTU)

220: main control unit (MCCU) 230: DS1 signal processing unit

240: video subscriber unit (VCU) 300: alarm display signal cell generator

310: failure occurrence detection unit 320: activation port confirmation unit

330: header error correction bit generator 340: payload generator

350: timer 360: utopia control signal generator

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

3 is a block diagram of the alarm display signal cell generator 300 according to the present invention, which includes a failure occurrence detection unit 310, an activation port checking unit 320, a header error correction bit generation unit 330, and a payload generation unit. 340, a timer 350, a utopia control signal generator 360, and a header generator 370.

The failure occurrence detection unit 310 detects a predetermined error detection signal by detecting when the clock and optical transmission / reception unit 210 (COTU) of the optical termination devices 110-1 to 110-16: ONU are detached or an error occurs. Outputs

That is, since the clock and optical transmission / reception unit 210 (COTU) has a function of supplying a cell bus clock to the video subscriber unit 240 (VCU), the cell bus clock from the clock and optical transmission / reception unit 210 (COTU) for a predetermined time. If not supplied, it is determined that the clock and optical transmitting / receiving unit 210 (COTU) is in a hernia state or an error state and outputs an error detection signal, thereby instructing the generation of a virtual path warning display signal (VP-AIS) cell.

The error detection signal is input to the timer 350, and starts counting the time when the virtual path alarm indication signal (VP-AIS) cell is generated.

The activation port checking unit 320 finds a subscriber port that is currently receiving video service among the subscribers it receives and outputs activation port information indicating this.

That is, since one video subscriber unit 240 (VCU) accommodates a plurality of subscribers (8 subscribers), each subscriber port is examined to determine which subscriber is currently receiving video service. Through this, the virtual path alarm indication signal (VP-AIS) cell is transmitted only to the subscriber port currently in operation.

The timer 350 is used to count the period in which the virtual path warning display signal VP-AIS cell is generated while the error detection signal is output from the failure occurrence detection unit 310.

According to ITU-T I.610, one virtual path alarm indication signal (VP-AIS) cell is generated per second. Used to find out the point of view. At this time, since one video subscriber unit 240 (VCU) has all eight subscriber ports, eight timers 350 are required.

If the timer 350 is implemented using a counter using a 12.96 MHz utopia transmit / receive clock as a reference clock, since the counter composed of about 24 flip-flops is required to measure the time of 1 second, the eight timers 350 are used. A total of 192 flip-flops are needed to create the.

As a preferred embodiment for reducing the number of flip-flops used, only one timer 350 is used to generate alarm signal cells in sequence for each subscriber port sequence.

4 is a timing diagram of generating an alarm display signal cell, and a timing of generating a virtual path alarm display signal (VP-AIS) cell when one timer 350 is used will be described.

All eight virtual path alarm indication signal (VP-AIS) cells are initially created in a one-second cell generation cycle and do not occur at any other time.

The video subscriber unit 240 (VCU) refers to the activation port information of the activation port checking unit 320, and if the corresponding port for the alarm display signal cell generated at the present time is activated, the cell among the utopia control signals. A start signal (SOC) and a transfer enable signal (Transfer Enable) are generated to start transmission of the virtual path alarm indication signal (VP-AIS) cell to the physical layer.

However, as a result of referring to the activation port information of the activation port confirming unit 320, if the corresponding port is inactive, the start of cell and the transmission permission signal of the utopia control signal are disabled. Inform the physical layer that there is no ATM cell to transmit.

That is, the alarm indication signal cells for each subscriber port are all made in order at the beginning of the cell generation cycle, and are transmitted only when the subscriber port corresponding to each of the generated cells is currently in operation.

The header generator 370 generates a header portion of the virtual path alarm display signal (VP-AIS) cell. At this time, since the value of the virtual path identifier (VPI) for each subscriber port is different, the header data for each subscriber port is also different. The header generation operation is performed with reference to the timer 350, and is performed at an initial time point at which the corresponding cell is generated for each of the eight virtual path alarm display signal (VP-AIS) cells.

The header error correction bit generator 330 calculates a value of a header error control (HEC) bit of the virtual path alarm display signal (VP-AIS) cell.

That is, since the video subscriber unit 240 has a unique virtual path identifier (VPI) value for each subscriber port, the header information generated by the header generator 370 is different from each other. The value of the header error correction (HEC) bit of the virtual path alarm indication signal (VP-AIS) cell shall be calculated.

At this time, the header error correction bit generator 330 operates according to the activation port information output from the activation port checking unit 320, and corresponds to a subscriber corresponding to the currently generated virtual path alarm display signal (VP-AIS) cell. It will not work unless the port is active.

The payload generation unit 340 generates payload data of the virtual path warning display signal (VP-AIS) cell. At this time, the payload generation unit 340 is operated according to the activation port information output from the activation port check unit 320, the subscriber port corresponding to the currently generated virtual path alarm display signal (VP-AIS) cell It won't work unless it's active.

The utopia control signal generator 360 generates various control signals for transmitting a virtual path alarm indication signal (VP-AIS) cell to the physical layer through the UTOPIA (UTOPIA: Universal Test & Operations PHY Interface for ATM) interface.

Utopia is a standard interface method for connecting ATM layer and physical layer. It establishes cell synchronization using start of cell (SOC) for data transmission at the cell level, and transmit permission signal. Create (Transfer Enable) to control the transfer. At this time, the cell start signal SOC indicates the first one byte of the ATM cell.

5 is an operation flowchart of the alarm display signal cell generator according to the present invention, with reference to this will be described in detail the operation of the present invention.

The failure occurrence detection unit 310 checks whether the optical transmission / reception unit 210 (COTU) is in a hernia state (step S510), and if it is determined that the hernia is in the hernia state, drives the timer 350 (step S520).

If the time required for generating eight virtual path alarm display signals (VP-AIS) cells has not passed since the timer 350 is inspected and the timer 350 is driven (step S530), the timer 350 corresponds to the current time. After generating the header data of the virtual path alarm display signal (VP-AIS) cell to be sent to the subscriber port (step S540), it is determined whether the corresponding subscriber port is in operation (step S550).

As a result of the determination in step S550, if the corresponding subscriber port is an active port (Active Port), the header error correction (HEC) bit for the corresponding subscriber port is calculated (step S560), and the payload data is generated (step S570). ). Then, after generating a control signal (cell start signal, transmission permission signal, etc.) for the utopia interface (step S580), the virtual path alarm display signal (VP-AIS) cell is transmitted using the physical layer (step S590). ).

Now, the process returns to step S530 to continue each step for the next subscriber port.

According to the present invention, information about the clock of the optical termination unit (ONU) and the state of the optical transmission / reception unit (COTU) is transmitted to each subscriber connected to the video subscriber unit (VCU) of the optical termination unit (ONU). Since the function can be implemented at a lower cost than the prior art, it is possible to develop an economical optical termination unit (ONU).

Claims (1)

It is installed in the optical termination unit (ONU) of the demand-dense optical subscriber transmission device (FLC-C system) to connect the set-top box of the subscriber side with the optical termination unit (ONU), so that each subscriber receives the video service. In the video subscriber unit (VCU), which is a device that enables the device to inform the subscriber of the error status, A failure occurrence detection unit for detecting an error in the clock and the optical transmission / reception unit COTU of the optical termination unit ONU and outputting an error generation signal; A timer for counting a generation period of a virtual path alert indication signal (VP-AIS) cell to be transmitted to a subscriber while the error occurrence signal is output; An activation port identification unit for investigating each subscriber port of the video subscriber unit, finding an active subscriber port, and outputting activation port information; A header generator configured to generate a header of the virtual path alarm display signal (VP-AIS) cell according to the output signal of the timer; A header error correction bit generator for calculating a header error correction (HEC) bit value of the virtual path alarm indication signal (VP-AIS) cell according to the activation port information; A payload generator configured to generate payload data of the virtual path alarm display signal (VP-AIS) cell according to the activation port information; And Utopia control signal for generating a control signal for transmitting the virtual path alarm display signal (VP-AIS) cells generated from the header generation unit, the header error correction bit generation unit, and the payload generation unit through a UTOPIA interface An alarm display signal cell generator of an image subscriber unit in an optical termination device of a demand-density optical subscriber transmission device, characterized in that it comprises a generator.