KR20000037862A - Controlling apparatus of optical route terminating system - Google Patents

Abstract

PURPOSE: A controlling apparatus of an optical route terminating system is provided to use an ATM service at the maximum between a subscriber terminal to the terminal termination by providing a video and distributable services having a higher broadband than the ISDN service as well as providing the ISDN service as a basic service. CONSTITUTION: A timing signal generator(310) generates a timing signal according to a system clock. A downward frame processor(320) inserts an ATM cell received from an external source into a downward frame according to the timing signal and a downward control signal transmitted from the timing signal generator(310) and outputs a serial downward frame signal. A light transmitter(330) converts the serial downward frame signal transmitted from the downward frame processor(320) to a downward light signal and transmits it. A wavelength dividing multiplexor(340) wavelength dividing-multiplexes an upward light signal received from a light distribution network and the downward light signal transmitted from the light transmitter(330). A light receiving unit(350) converts the light signal multiplexed by the wavelength dividing multiplexor(340) to an electric signal and extracts a clock to restore the receiving data. An upward frame processor(360) receives a receiving data restored by the light receiving unit(350), extracts an upward frame and outputs it to the ATM cell according to the timing signal and the upward control signal transmitted from the timing signal generator(310). A controller(370) controls the downward frame processor(320) by providing a downward control signal and controls the upward frame processor(360) by providing an upward control signal, according to the timing signal transmitted from the timing signal generator(310). A microprocessor(380) controls the downward frame processor(320), the upward frame processor(360) and the controller(370).

Description

Control device of optical line termination system

The present invention relates to an optical fiber control apparatus of an optical line termination system in an Asynchronous Transfer Mode-Passive Optical Network (ATM-PON).

In general, a communication network consists of three main parts: the core network, the access network and the customer premises network.

The transmission network is composed of service nodes, inter-transmission devices and exchanges to perform service provision, exchange, billing and transmission functions, and the subscriber premises network is composed of network termination devices and various terminals such as telephones and personal computers. And transmits and receives images and video information.

The access network is a part connecting the delivery network and the subscriber home network, and is generally defined as a network extending from the subscriber's house to the nearest local exchange.

Therefore, as the number of exchanges in the transport network gradually decreases, the role of the access network in the entire communication network becomes increasingly important.

1 is a configuration schematic diagram of an ATM-PON, and is a configuration schematic diagram of an ATM-PON adopted as an ITU-T Recommendation G.983 in February 1998 to support ATM through a PON, and is a system between the reference points T and V. It is connected to a Telecommunication Management Network (TMN) through a reference point and managed as one element.

In addition, ATM-PON supports video and distribution services with a bandwidth above the Integrated Services Digital Network (ISDN) basic speed.

In addition, ATM-PON is composed of optical line termination (OLT), optical distribution network (ODN) and optical network termination (ONU), and ODN uses passive optical devices. An optical transmission means between the OLT and the ONU is provided, and the ONU is connected to the ODN to provide a user side matching function of the access network.

OLT is connected to one or more ODN to provide network side matching function, manage all PON related functions in ATM transport system, and switch network through standard interface such as VB5.x, V5.x, NNI, etc. Is connected to.

The hierarchical structure of the ATM-PON is divided into a physical medium layer, a transmission convergence (TC) layer, and a path layer.

The path layer corresponds to the virtual path (VP: Virtual Path) of the ATM layer, and the TC layer corresponds to the TC sublayer of B-ISDN and is divided into an adaptation sublayer and a PON transmission sublayer. That is, AF (Adaptation Function) is an application function unit.

The PON transmission sublayer provides PON-specific transmission functions in the optical distribution network, such as ranging, cell slot allocation, band allocation, information protection, frame alignment, burst synchronization, and bit / byte synchronization. Provides cell rate matching, header error correction (HEC) calculation, and error correction. The physical medium layer performs a function of transmitting a data bit string using an optical line.

However, the conventional optical access network uses a time-division multiple access (TDM) method with a pair of optical cables per subscriber, and a time-division multiple access (TDMA) method with an uplink. Because of the structure of transmitting digital TV signal, there was a problem that the initial installation cost of the optical cable is large and it is difficult to provide various and flexible services.

Accordingly, the present invention has been made to solve the above problems, by providing a narrowband Integrated Services Digital Network (ISDN) service as a basic service using a single strand of optical cable for each subscriber, the band above It provides video and distributive services to provide network operators with the flexibility to meet future subscriber requirements and to make full use of the terminal's end-to-end ATM service capabilities not only for business subscribers but also for residential subscriber terminals. It is an object of the present invention to provide a control device for an optical fiber termination system.

1 is a configuration diagram of an ATM-PON.

2 is a frame structure diagram of an ATM-PON applied to the present invention;

Figure 3 is a block diagram of one embodiment of a control device for the optical fiber termination system according to the present invention.

4 is a block diagram of an embodiment of a downlink frame processor of FIG.

FIG. 5 is a block diagram of an embodiment of an uplink frame processor of FIG. 3; FIG.

6 is a block diagram of an embodiment of the controller of FIG. 3;

Explanation of symbols on the main parts of the drawings

310: timing signal generator 320: downlink frame processor

330: optical transmitter 340: wavelength division multiplexer

350: optical receiver 360: uplink processor

370: control unit 380: microprocessor

According to an aspect of the present invention, there is provided a control apparatus for an optical fiber termination system, comprising: timing signal generating means for generating a timing signal according to a system clock; Down frame processing means for inserting an asynchronous transfer mode cell received from the outside into a down frame according to the down control signal and the timing signal, and outputting a serial down frame signal; Optical transmission means for converting and transmitting the serial downlink frame signal into a downlink optical signal; Wavelength division multiplexing means for wavelength division multiplexing the uplink optical signal and the downlink optical signal received from the outside; Optical receiving means for converting an optical signal multiplexed by the wavelength division multiplexing means into an electrical signal and extracting a clock to recover received data; Up frame processing means for receiving received data recovered by the optical receiving means and extracting an up frame according to an up control signal and the timing signal to output a user cell; And control means for controlling the uplink frame processing means by providing the downlink control signal and controlling the uplink frame processing means by providing the uplink control signal according to the timing signal.

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

2 is a frame structure diagram of an ATM-PON according to the present invention, and shows a transmission frame structure of symmetrical (up and down 155.520 Mbps) and asymmetrical (downlink 622.080 Mbps, uplink 155.520 Mbps) ATM-PONs.

Since there are physical layer operations administration and maintenance (PLOAM) cells in every 28 time slots, two PLOAM cell slots and 54 53-byte ATM cell slots for down-symmetrical 155.520 Mbps frames and eight for downlink asymmetric 622.08 Mbps frames. There are PLOAM cell slots and 216 53 byte ATM cell slots.

Therefore, in the asymmetric PON, the number of ATM cells in the downlink T frame is four times the symmetrical type.

The uplink frame has 53 time slots, and each time slot is allocated to one of a PLOAM cell slot, an ATM cell slot, and a divided slot under the control of the OLT.

Here, the divided slot is used to convey the ONU queue state for dynamic band allocation of the media access control (MAC) protocol.

56 bytes of uplink time slots consist of 3 bytes of overhead information and 53 bytes of ATM cells.

The PLOAM cell for OAM (operation administration and maintenance) of ATM-PON consists of 5 bytes of header and 48 bytes of payload information, and the payload information of downlink PLOAM cell is uplink with time slot grant information and maintenance. It consists of a message for transporting maintenance management information, the uplink PLOAM cell consists of a message and optical power control information.

OAM related signals mounted on the OLT and ONU are mapped through the message field of the PLOAM cell.

Figure 3 is a configuration diagram of an embodiment of a control device for the optical fiber termination system according to the present invention.

As shown in FIG. 3, the control apparatus of the optical line termination system of the present invention includes a timing signal generator 310 and a timing transmitted from the timing signal generator 310 for generating a timing signal according to a system clock. According to the signal and the downlink control signal, the downlink frame processor 320 for inserting an ATM cell received from the outside into the downlink frame, and outputs a serial downlink frame signal, and the serial downlink frame signal transmitted from the downlink frame processor 320 A wavelength division multiplexer 340 for wavelength division multiplexing the downlink optical signal received from the optical distribution network and the uplink optical signal received from the optical distribution network and the downlink optical signal transmitted from the optical distribution network The optical receiver 350 converts an optical signal multiplexed by the wavelength division multiplexer 340 into an electrical signal, extracts a clock, and recovers received data, and a timing signal generator 310. In accordance with the timing signal and the uplink control signal transmitted from the uplink frame processor 360 for outputting an ATM cell by receiving the received data recovered by the optical receiver 350 to extract the uplink frame, and a timing signal generator 310 A control unit 370 for controlling the downlink frame processor 320 by providing a downlink control signal and controlling the uplink frame processor 360 by providing an uplink control signal according to the timing signal transmitted from 320, a microprocessor 380 for controlling the uplink frame processor 360 and the controller 370.

The operation of the control device of the optical fiber termination system of the present invention having the above configuration will be described in detail as follows.

The timing signal generator 310 receives a system clock and provides a timing signal to the downframe processor 320, the upframe processor 360, and the controller 370.

The downlink frame processor 320 receives a byte or word ATM cell from an external ATM layer processor through an utopia interface that is an ATM forum standard, encrypts it, and inserts the same into a downlink frame as shown in FIG. 2 together with a PLOAM cell. Function, bit interleaved parity (BIP) -8 calculation and insertion for downlink frame data, distributed sample scrambling, HEC calculation and insertion, and serial conversion of parallel data at 155.520 Mbps or 622.080 Mbps.

The optical transmitter 330 converts the serial frame data transmitted from the downlink frame processor 320 into an optical signal and outputs a 155.520 Mbps or 622.080 Mbps optical signal to the wavelength division multiplexer 340.

The wavelength division multiplexing unit 8 performs wavelength division multiplexing on a downlink optical signal having a wavelength of 1550 nm transmitted from the optical transmitter 330 and an uplink optical signal having a wavelength of 1310 nm from the optical distribution network to generate an optical signal having a wavelength of 1550 nm. It transmits to the optical distribution network, and transmits the optical signal having a 1310 nm wavelength to the optical receiver 350.

The optical receiver 350 converts an uplink 155.520 Mbps optical signal transmitted from the wavelength division multiplexer 340 into an electrical signal, extracts a clock, recovers received data, and transmits the received data to the upstream frame processor 360.

The uplink frame processor 360 receives the 155.520 Mbps data extracted by the optical receiver 350 to search the overhead field to identify slot boundaries and generate phase difference information with reference slot signals and slot aligned data. Receive and descramble, perform ATM cell header error checking, correct single-bit errors, perform BIP-8 calculations, and separate user cells, IDLE cells, and PLOAM cells from receiving normal cells The cell is immediately discarded and the user cell is forwarded to the receiving utopia matching unit.

The controller 3 controls the down frame processor 320 and the up frame processor 360.

The microprocessor 380 performs a shared media protocol (MAC) protocol for fair and dynamic bandwidth allocation to each ONU, performs a part of ranging function, generates up and down messages, analyzes functions, and various alarms. It collects signals and reports them to the operating system, and provides the variables necessary to control each block.

4 is a block diagram of an embodiment of the downlink frame processor of FIG. 3.

As shown in FIG. 4, the downlink frame processor of FIG. 3 includes a first-in first-out unit 321 for temporarily storing an ATM cell from the outside and a first-in first-out unit according to an encryption key transmitted from the controller 370. An encryption unit 322 for encrypting the parallel ATM cell transmitted through 321 and outputting the encrypted ATM cell, message data from the microprocessor 380 and encryption status information and ranging from the control unit 370; A message generator 323 for receiving the information and outputting a message for determining the content of the downlink message, and under the control of the controller 370, permission for receiving the permission information from the microprocessor 380 and outputting the uplink permission information The information manager 324 and the message generator 323 receive the downlink message and the uplink permission information from the permission information manager 324, and generate the PLOAM cell to the cell generator 325 and the encryption unit 325. Encrypted by ATM The downlink frame generator 326 which receives the PLOAM cell from the cell and the cell generator 325 to generate the downlink frame, and inserts the downlink frame transmitted from the downlink frame generator 326 into a specific byte of the PLOAM cell And a downlink frame output unit 327 for outputting serial data.

The operation of the downlink frame processor of FIG. 3 having such a structure will be described in detail as follows.

The first-in-first-out unit 321 receives ATM cells from the ATM layer and performs cell rate matching functions of the upper layer ATM layer and the ATM-PON physical layer, which are the utopia interface functions of the ATM forum.

The encryption unit 322 encrypts 8-bit parallel ATM cell data read at 78 Mbps or 19 Mbps ATM-PON physical layer speed using a 3-byte encryption key received from each ONU.

The message generator 323 receives the message data generated by the microprocessor 380, the encryption state information and the ranging message generated by the controller 370, and determines the contents of the downlink message according to the ONU state and processing priority. The cell generator 325 outputs the function.

The permission information manager 324 stores permission information generated by the microprocessor 380 in the memory based on the ONU-specific buffer status information for a fair and dynamic bandwidth allocation of the uplink band and then stores the downlink frame according to the downtime timing signal. A function of mapping to a PLOAM cell and a function of outputting permission information read from a memory according to a reference SOC_1 signal from the controller 370 as an uplink permission information signal.

The cell generator 325 receives the message from the message generator 325 and the permission information from the permission information manager 324 to generate a complete PLOAM cell and output the complete PLOAM cell to the downlink frame generator 326.

The downlink frame generator 326 receives the downlink ATM cell from the encryption unit 322 and the PLOAM cell from the cell generator 325 to generate the downlink frame of FIG. 2 and output the downlink frame to the downlink frame output unit 327. Performs a function of outputting a timing signal (that is, Tploam, Tframe, downlink SOC, etc.) necessary for the function and the function of the controller 370.

The downlink frame output unit 327 receives the downlink frame data, calculates a BIP-8 for the data in the Tploam period of FIG. 2, and inserts the result into the PLOAM cell BIP-8 byte position. Performs distributed sample scrambling, inserts HEC calculations for each cell in a frame, converts 8-bit parallel frame data into serial frame data of 155.520 Mbps or 622.08 Mbps, and outputs it to the optical transmitter 330 Do this.

FIG. 5 is a block diagram of an uplink processor of FIG. 3.

As illustrated in FIG. 5, the uplink frame processor of FIG. 3 receives uplink serial data from the optical receiver 350 and slot information and a reference signal from the controller 370 to identify a boundary of the uplink slot, and then identifies the uplink slot. A slot boundary identification unit 361 that outputs a cell and a cell identified by the slot information and the slot boundary identification unit 361 are received from the control unit 370, and the slots are divided to separate and output the divided slots and the cell data. Receiving slot information from the slot processing unit 362, the slot first-in first-out unit 363 temporarily storing the divided slots transmitted from the slot processing unit 362 and outputting the divided slots to the microprocessor 380, and the controller 370. Message type that receives the PLOAM cell from the cell extractor 364 for extracting the PLOAM cell and the user cell from the cell data transmitted from the slot processor 362 and the slot information and the cell extractor 364 from the controller 370. By identifying A message identification unit 365 for separating and outputting each message; a message first-in-first-out unit 366 for temporarily storing a message for processing by software transmitted from the message identification unit 365 and outputting the message to the microprocessor 380; In response to the message for processing by hardware from the message identification unit 365, a password and ranging related message is transmitted to the control unit 370, and the performance information message is transmitted to the performance information processing unit 368. The unit 367 receives the slot information from the control unit 370 and the performance information message from the message transfer unit 367, and extracts the data by the cell extracting unit 364 and the performance information processing unit 368 for outputting various alarm signals. A first-in-first-out unit 369 for temporarily storing and outputting the user cell to the outside, and a memory 391 for storing a performance analysis result of the performance-information processing unit 369.

The operation of the uplink frame processor of FIG. 3 having the structure as described above will be described in detail as follows.

The slot boundary identification unit 361 receives 155.520 Mbps up-serial data coming from each ONU from the optical receiver 350, the slot information from the control unit 370, and the reference SOC, and identifies the boundary of the up slot. Is transmitted to the slot processing unit 362, and compares the boundary point of the identified slot with the reference SOC, and outputs the bit value signal that is the difference value to the control unit 370 and the performance information processing unit 368, and generates the slot boundary identification at the instant. The distance measurement stop signal is transmitted to the control unit 370.

After descrambling data scrambled from each ONU, the slot boundary identification unit 361 outputs to the slot first-in first-out unit 363 in the case of a divided slot cell having queue information of each ONU. In the case of other cells, the cell header error check is performed to correct a single bit error, the BIP-8 calculation is performed, and then the cell data is transferred to the cell extractor 363. The error check result and the BIP-8 calculation result value are performance information. It performs a function of transferring to the processing unit 368.

The slot first-in first-out unit 363 transfers the stored divided slot data to the microprocessor 380.

The cell extractor 364 classifies the upstream cell, discards the idle cell, outputs the user cell to the cell first-in-first-out unit 369 and the performance information processing unit 368, and transmits the PLOAM cell to the message identification unit 365. It performs the function.

The message identifying unit 365 receives the slot information signal from the control unit 370 and the PLOAM cell from the cell extracting unit 364 and checks whether the ONU number and the message number match the slot information signal, and then checks the result of the test. Message to be processed by the processing unit 368, and checks the message type to be processed by the hardware delivered to the message delivery unit 367, and the message to be processed by the software to the message first-in, first-out (366). .

The message transfer unit 367 receives the message data from the message identification unit 365 and transfers the encryption and ranging related message back to the control unit 370, and extracts the contents of the performance information message to the performance information processing unit 368. Perform the function of passing.

The performance information processing unit 368 includes a bit value signal from the slot boundary identification unit 361, a header error result signal from the slot processing unit 362, an ONU number and a message number comparison result signal from the message identification unit 365, and a cell. Receives user cell data from the extractor 364 and message contents from the message transfer unit 367 and analyzes the performance analysis result stored in the memory 391 for each ONU to generate various alarm signals and threshold alarm signals. The microprocessor 380 transfers the result of the analysis processing for each slot to the memory 391.

The cell first-in, first-out unit 369 performs a utopia interface function, which is an ATM forum standard, and temporarily stores an ATM cell from the cell extraction unit 364 and outputs the ATM cell at an ATM layer speed.

The memory 391 provides performance analysis results stored for each ONU to the performance information processing unit 368 and the microprocessor 380 and stores the results processed by the performance information processing unit 368 in units of slots.

6 is a block diagram of an embodiment of the controller of FIG. 3.

As shown in FIG. 6, the controller of FIG. 3 includes a reference signal generator 371 which provides a reference signal to the downlink frame processor 320 and the uplink frame processor 360, and the downlink frame processor 320. The permission information analysis unit 372 analyzes the transmitted uplink permission information and outputs slot information, and receives the encryption status information and the encryption key by receiving the slot information and the message from the uplink frame processor 360 from the permission information analyzer 372. From the encryption processor 373, the timing-related signal from the downlink frame processor 320, ranging state information from the microprocessor 380, and the uplink frame processor 360. The ranging processing unit 374 receives the reception error, the distance measurement stop signal and the bit value signal, and the slot information from the permission information analyzing unit 372, and delivers the ranging message to the downlink frame processing unit 360. Equipped.

The operation of the controller of FIG. 3 having such a structure will be described in detail as follows.

The reference signal generator 371 receives the downlink SOC signal from the downlink frame processor 320 and generates a reference SOC signal delayed by a Teqd signal, which is a total round trip delay time transmitted from the microprocessor 380, to thereby uplink frame processor 360. And generates a reference SOC_1 signal one slot faster than the reference SOC signal and outputs the signal to the downlink frame processor 320.

The permission information analysis unit 372 analyzes the uplink permission information from the downlink frame processor 320 to determine which cell from which ONU a slot is currently received to determine the uplink frame processor 360 and the ranging processor 374. Perform the function to output to.

The encryption processing unit 373 receives the received message signal from the uplink frame processor 360 and the slot information signal from the permission information analyzer 372 and extracts an encryption key included in the received message signal for each ONU, thereby extracting the downlink frame processor ( 320).

The ranging processor 374 may include a Tploam, a Tframe signal, a ranging state information signal from the microprocessor 380, a Teqd signal, a total round trip delay time, and an uplink frame processor 360. Receives the error, distance measurement stop, bit value signal, and slot information signal from the permission information analyzer 372, and performs distance measurement function for each ONU connected to the PON. The cell transmission delay time of each ONU is calculated to be virtually the same distance, and the result is included in the ranging message signal and output to the downlink frame processor 320.

Although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, the present invention uses a wavelength-division multiplexing scheme with a single optical fiber, and distributes 622.08 Mbps in the downlink and 155.52 Mbps in the narrowband service and broadband video and distribution services up to 20 km. In addition, by transmitting the end-to-end ATM cell to the residential subscriber station, it can be variously applied to the field that can take full advantage of the ATM's service capabilities.

Claims (4)

In the control device of the optical fiber termination system, Timing signal generating means for generating a timing signal in accordance with the system clock; Down frame processing means for inserting an asynchronous transfer mode cell received from the outside into a down frame according to the down control signal and the timing signal, and outputting a serial down frame signal; Optical transmission means for converting and transmitting the serial downlink frame signal into a downlink optical signal; Wavelength division multiplexing means for wavelength division multiplexing the uplink optical signal and the downlink optical signal received from the outside; Optical receiving means for converting an optical signal multiplexed by the wavelength division multiplexing means into an electrical signal and extracting a clock to recover received data; Up frame processing means for receiving received data recovered by the optical receiving means and extracting an up frame according to an up control signal and the timing signal to output a user cell; And Control means for controlling the downlink frame processing means by providing the downlink control signal according to the timing signal, and controlling the uplink frame processing means by providing the uplink control signal. Control device of the optical fiber termination system comprising a. The method of claim 1, The downward frame processing means, First-in, first-out means for temporarily storing the asynchronous delivery mode cell; Encryption means for outputting an asynchronous delivery mode cell encrypted by encrypting the parallel asynchronous delivery mode cell transmitted through the first-in first-out means according to the control of the control means; Message generating means for receiving message data from the outside and encryption status information and ranging information from the control means and outputting a message for determining the content of the downlink message; Permission information management means for receiving permission information from the outside and outputting upward permission information according to the control of the control means; Cell generation means for receiving a downlink message from the message generation means and uplink permission information from the permission information management means to generate a PLOAM cell; Downlink frame generation means for receiving asynchronous delivery mode cells encrypted by the encryption means and the PLOAM cell to generate a downlink frame; And Downlink frame output means for inserting and outputting the downlink frame transmitted from the downlink frame generation means to a specific byte of the PLOAM cell Control device of the optical fiber termination system comprising a. The method of claim 1, The upward frame processing means, Slot boundary identification means for receiving the up-serial data from the optical receiving means and the slot information and the reference signal from the control means to identify the boundary of the up slot, and outputting the identified cell; Slot processing means for receiving the slot information and the cell identified by the slot boundary identification means from the control means, dividing the slot, and separating and outputting the divided slot and the cell data; Slot first-in first-out means for temporarily storing the divided slots transmitted from the slot processing means and outputting them to the outside; Cell extracting means for receiving slot information from the control means and extracting a PLOAM cell and a user cell from cell data transferred from the slot processing means; Message identification means for receiving the slot information from the control means and the PLOAM cell from the cell extraction means, identifying the message type, and separating and outputting each message; Message first-in, first-out means for temporarily storing and outputting a message for processing by software delivered from said message identification means to the outside; Message transmission means for receiving a message for processing by hardware from the message identification means and transmitting an encryption and ranging related message to the control means, and transmitting the performance information message to the performance information processing means; Performance information processing means for receiving the slot information from the control means and the performance information message from the message transmission means and outputting various alarm signals; First-in, first-out means for temporarily storing the user cells extracted by the cell extracting means and outputting them to the outside; And Storage means for storing a performance analysis result of the performance information processing means; Control device of the optical fiber termination system comprising a. The method of claim 1, The control means, Reference signal generating means for providing a reference signal to the downward frame processing means and the upward frame processing means; Permission information analysis means for analyzing slot permission information transmitted from the downlink frame processing means and outputting slot information; Encryption processing means for receiving the slot information and the message from the uplink frame processing means from the permission information analyzing means and transferring the encryption status information and the encryption key to the downlink frame processing means; And Input timing related signals from the downlink frame processing means, ranging state information from the outside, reception errors from the uplink frame processing means, distance measurement stop signals and bit value signals, and slot information from the permission information analyzing means; Ranging processing means for receiving and transmitting a ranging message to the downlink frame processing means; Control device of the optical fiber termination system comprising a.