KR20020080617A - An implementation method of predictor for data recovery and phase monitoring in ATM-PON - Google Patents

Abstract

PURPOSE: A method of implementing a predictor for recovering data and monitoring a phase in an ATM-PON(Passive Optical Network) is provided to supply a delimiter of a next cell and a continuing time of a PMSE(Phase Monitor and Synchronizer Enable) signal from an OLT(Optical Line Termination) receiver, thereby efficiently performing data recovery and phase monitoring and stabilizing a system. CONSTITUTION: An ATM-PON connects an OLT with an ONU(Optical Network Unit) by using a passive optical element, and has a functional module of a transmission receiving layer in the ONU, then has a predictor in the functional module. The ATM-PON recognizes properties of a cell where the predictor is upwardly incoming. The ATM-PON inputs authorized information from a delimiter of a next cell and a PRM(PLOAM, Ranging, Mnislot) cell processor according to the properties of the cell, and performs an internal processing, then supplies delimiter information and phase monitoring information to a data recovery unit.

Description

An implementation method of predictor for data recovery and phase monitoring in ATM-PON}

The present invention provides a method of implementing a predictor for data recovery and phase monitoring of an Asynchronous Transfer Mode-Passive Optical Network (ATM-PON) and a computer-readable recording medium recording a program for implementing the method. The present invention relates to an ATM-PON, in which an optical line termination (OLT) and an optical network unit (ONU) are connected to each other using passive optical elements, and a plurality of ONUs share one optical fiber. The present invention relates to a method of implementing a predictor for data recovery and phase monitoring at a receiving unit of an OLT, and a computer-readable recording medium recording a program for realizing the method.

In ATM-PON, the downlink signal is transmitted through one optical cable connected to the OLT installed in the national office, and it passes through a splitter and branches up to 64 strands to be broadcast to ONU. In contrast, signals transmitted by multiple ONUs are multiplexed via a fiber to the OLT via a combiner.

In contrast, the signals transmitted by multiple ONUs are multiplexed via a fiber to the OLT via a combiner. The transmission rate supports symmetrical up / down 155.52 / 155.52 Mbits / s and asymmetrical 622.08 / 155.52 Mbits / s.

1 is a configuration diagram of an ATM-PON system in a general ITU-T G.983.1, and is composed of OLT, ONU, and ODN (Optical Distribution Network).

FIG. 2 is a frame structure diagram for the case of 155.52 / 155.52 Mbits / s up / down of a typical ATM-PON. The downlink frame includes two physical layer OAM (PLOAM) cells in 56 slots.

Here, the PLOAM cell is inserted every 28 timeslots. The OLT allows the ONU to send the ATM cell to the OLT using a grant field carried in the downlink PLOAM cell. The uplink frame consists of 53 time slots. Each time slot has 53 bytes of ATM cell and 3 bytes of overheader. There are fields of guard time, preamble, and delimiter within the 3 bytes of header.

Since the downlink signal is broadcast through a splitter, there is no particular difficulty in solving the security problem. However, since the signal sent upwards is multiplexed through the combiner, even if the OLT specifies which timeslots to use for a particular ONU, the collision between cells is different if the distance between each ONU and the OLT (0-20 Km) is different. This can happen. It is a principle that ATM networks should avoid collisions for efficient use of link capacity and quality of service. However, the splitter and coupler used in the PON can not solve this problem because it is implemented as a passive element for low cost and easy maintenance. To solve this problem, OLT detects newly registered ONUs, measures distances, and assigns equalization delay, the time all ONUs wait to transmit a cell, so that they appear to exist virtually in the same location. This is called ranging protocol. However, this has already been standardized in G.983.1.

Therefore, in the current technical field, to implement a predictor to determine which ONU and which function the upstream cell flows for ranging and media control in the TC layer of the OLT. There is a need for a solution.

The present invention has been proposed in order to solve the above problems, and connects a broadband national device (OLT: Optical Line Unit) and an optical subscriber unit (ONU: Optical Network Unit) using a passive optical device and Provides a method of implementing a predictor that enables ONU to perform data recovery and phase monitoring at the receiver of an OLT through an ATM-PON that shares one fiber, and provides a computer-readable recording medium that records a program for implementing the method. Its purpose is to.

1 is an exemplary configuration diagram of an ATM-PON system in a general ITU-T G.983.1.

2 is a frame structure diagram for the case of 155.52 / 155.52 Mbits / s up / down of a typical ATM-PON.

3 is an exemplary configuration diagram of an OLT receiver including a predictor to which the present invention is applied.

4 is a diagram illustrating an embodiment of a method for implementing data recovery and phase monitoring predictor in an asynchronous transmission mode-passive optical branch network according to the present invention;

5 is an exemplary view illustrating a method of assigning an approval value of a data recovery and phase monitoring predictor according to the present invention.

In accordance with another aspect of the present invention, there is provided a method for implementing a predictor for data recovery and phase monitoring of an asynchronous transmission mode-passive optical branch network, using a broadband optical device (OLT) and an optical subscriber access device (ONU). A first step of making a connection by using the optical subscriber access unit (ONU) and having a transmission convergence layer functional module in the transmission convergence layer functional module; A second step of identifying characteristics of a cell into which the provided predictor flows upward; And receiving the approval information from the delimiter and PRM (PLOAM, Ranging, Minislot) cell processor of the next cell according to the characteristics of the cell, performing internal processing, and then monitoring the delimiter information and phase with the data recovery unit. It comprises a third step of providing information.

In addition, the present invention connects the broadband station device (OLT) and the optical subscriber access device (ONU) to the asynchronous transmission mode-passive optical splitter network having a processor by using a passive optical element, and the optical subscriber access device (ONU). A first function having a transmission convergence layer function module and including the predictor in the transmission convergence layer function module; A second function of identifying a characteristic of a cell into which the provided predictor flows upward; And receiving the approval information from the delimiter and PRM (PLOAM, Ranging, Minislot) cell processor of the next cell according to the characteristics of the cell, performing internal processing, and then monitoring the delimiter information and phase with the data recovery unit. A computer readable recording medium having recorded thereon a program for realizing a third function of providing information is provided.

The present invention provides a method for implementing a predictor in an ATM-PON OLT receiver, comprising: a predictor in a transmission convergence layer function module of a broadband office device (OLT) receiver, wherein the predictor includes a shift resist, a NAND gate, and an AND. It provides a method of implementing a predictor that includes a) gate, a plurality of OR gate, the admission memory, and a selector.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is an exemplary configuration diagram of an OLT receiver including a predictor to which the present invention is applied.

As shown in FIG. 3, the data recovery unit recovers a bit synchronization signal using a preamble of an uplink cell input, and provides a cell division function by recovering a byte synchronization signal using a delimiter. do. Bit interleaved parity (BIP) calculation and header error checking are performed on the data that has been demixed.

Since the uplink cell is delivered by the grant provided by the OLT itself, the OLT can see that what is currently coming up through the predictor is some kind of data sent by an ONU. Therefore, the demultiplexing process may be determined by the predictor, not the cell header information. As a result, the data cell is transferred to the cell buffer, the idle cell is discarded, and the PLOAM cell, ranging cell, mini slot, and the like are transferred to a PRM (PLOAM, Ranging, Minislot) cell processor.

Hereinafter, a method for predicting data recovery and phase monitoring in an asynchronous transmission mode-passive optical branch network according to the present invention will be described.

4 is a diagram illustrating an embodiment of a method for implementing data recovery and phase monitoring predictor in an asynchronous transmission mode-passive optical branch network according to the present invention.

As shown in FIG. 4, the method of performing the predictor varies according to the type of grant provided by the media access control (MAC) scheduler in the PRM cell processor of FIG. 3. The predictor reads 27 acknowledgments or 26 acknowledgments at once from the acknowledgment table provided by the MAC scheduler in the period (T _f / 2) of the PLOAM cell. That is, they are stored in 28 shift registers by the uplink 56-byte cell clock C'CLK. The information stored in the shift register is stored one by one in 108 shift shift registers by uplink 56-byte cell clock.

In more detail, the first upstream 56-byte cell clock is moved to the TOL (Trailer of Line) and continues to the right. Finally, when it is in the position just before the header of line (HOL), it is now used as a delimiter of a cell that will soon arrive at the receiver.

As acknowledgments arrive at the TOL from the front end buffer, they are handled differently depending on the value of each acknowledgment.

First, the case where a window is not opened is demonstrated. In this case, the grant values correspond to unassigned grants (UA_GR), data grants, and PLOAM grants (PLOAM grants, PL_GR), which arrive at the position just before HOL without any further processing in the front end buffer. As shown in FIG. 4, each grant value is transferred to the data recovery unit as a delimiter value at the time of the upstream 56-byte cell clock (C'CLK) falling transition.

Immediately after the delimiter is written, a Phase Monitor and Synchronizer Enable (PMSE) signal is generated, whose duration is zero for unassigned acknowledgments, one byte for PLOAM grants and data grants, and one byte for split slots. 8 times each.

Next, the case where a window is opened is demonstrated. The applied ranging procedure assumes that a pre-allocation delay is applied according to the predicted distance of the optical cable in order to reduce the window length. Range approvals or PLOAM approvals are always inserted into the window. Thus, if the approval currently placed at the front of the shear buffer (shift register) is a ranging approval (RA_GR) or PLOAM approval to obtain a serial number or to measure equalization delay, then the approval currently in the TOL is placed across the window. It will be unassigned approval. Therefore, in order to distinguish between an unassigned grant inside a window and an unassigned grant outside the window, a special grant value is used in the present invention. This is shown in FIG.

W_Pro (Window proceeding) and W_End (Window end) of the present invention are approval values used only internally. If the length of the window corresponds to 2n + 1 cell, the middle is a batch approval or a PLOAM approval, and the last approval. Corresponds to W_End, and everything else has W_Pro approval value. The configuration of the window to obtain the serial number is [W_Pro, ... , RA_GR, W_Pro, ... , W_End], when RA_GR is placed at the front of the front end buffer as shown in FIG. 4, it is stored in the grant storage and the window reaches the time immediately before the TOL, but before the T _eqd -1 cell time. It takes When W_Pro arrives just before HOL, the value provided as a delimiter is RA_GR stored in grant storage. And, the duration of PMSE provides 56 bytes. This behavior is maintained until W_End arrives just before the HOL. Therefore, the duration of the PMSE signal is maintained by the length of the window.

To measure the equalization delay, a PLOAM acknowledgment is inserted so that the window configuration [W_Pro, ... , PL_GR, W_Pro, ... , W_End], as described above, the PLOAM grant value is stored in the grant storage. After T _eqd -1 cell time, W_Pro arrives just before HOL, and the PL_GR value is provided as a delimiter value. The duration of the PMSE signal is 56 bytes. When the PLOAM acknowledgment in the window arrives at the position just before HOL, the current value is W_Pro, so the PMSE duration is 56 bytes long. By doing this, it is possible to distinguish between the case of general PLOAM approval and the case of PLOAM approval in the window, and the PMSE duration can be different.

The method of the present invention as described above may be implemented as a program and stored in a computer-readable recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.).

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be apparent to those of ordinary knowledge.

As described above, the present invention relates to a predictor implementation method for determining which ONU is a cell which is introduced upward for ranging and medium control in a TC layer of an ATM-PON OLT and which cell performs a function. By using the predictor according to the present invention, the OLT receiver provides the duration of the delimiter and PMSE (Phase Monitor and Synchronizer Enable) signal of all cells to the next position, thereby efficiently and stably providing data recovery and phase monitoring of the receiver. It is possible to stabilize the whole system. In addition, there is an additional effect of enabling the ONU to monitor the band usage using the predictor of the present invention.

Claims (7)

A method of implementing a predictor for data recovery and phase monitoring of an asynchronous transmission mode-passive optical branch network, The broadband station device (OLT) and the optical subscriber access device (ONU) are connected by using a passive optical element, and the transmission convergence layer function module is provided in the optical subscriber access device (ONU), and the predictor is provided in the transmission convergence layer function module. First step; A second step of identifying characteristics of a cell into which the provided predictor flows upward; And According to the characteristics of the cell, after receiving the approval information from the delimiter and PRM (PLOAM, Ranging, Minislot) cell processor of the next cell and performing internal processing, the delimiter information and phase monitoring information to the data recovery unit Third step to provide A method of implementing a predictor for data recovery and phase monitoring of an asynchronous transmission mode-passive optical branch network comprising a. The method of claim 1, The second step, Asynchronous transmission mode-data recovery and phase monitoring of the passive optical branch network, characterized in that it is determined by which optical subscriber access device the cell flowing upward for ranging and media control, which cell performs a function, etc. How to implement a predictor. The method according to claim 1 or 2, The predictor, An asynchronous transmission mode-passive light, characterized in that it comprises a plurality of shift registers, NAND gates, AND gates, OR gates, acknowledgment storages and selectors in the transmission convergence layer functional module. A Predictor Implementation Method for Data Recovery and Phase Monitoring of Networks. The method according to claim 1 or 2, The predictor, Within the transmit convergence layer functional module, it operates by an upward 56-byte cell clock, including a plurality of shift registers, NAND gates, AND gates, OR gates, grant storages, and selectors. Asynchronous transmission mode-manual, characterized by generating delimiter information, phase monitoring signal, equalization delay (T _d ) counter enable signal, and equalization delay (T _d ) counter disable signal. Predictor Implementation Method for Data Recovery and Phase Monitoring of Optical Branch Network. The method according to claim 1 or 2, The predictor, A plurality of shift registers, a NAND gate, an AND gate, an OR gate, an acknowledgment storage device, and a selector within the transmission convergence layer functional module, and generate a phase monitoring signal. The data recovery of the asynchronous transmission mode-passive optical splitter network is characterized by maintaining the duration of "0" for unallocated approval, one byte for PLOAM approval and data approval, and one byte for split slot approval. Predictor Implementation Method for Phase Monitoring. The method according to claim 1 or 2, The predictor, When performing the ranging function within the transmission convergence layer function module, a special transmission value is used to distinguish between an unassigned approval inside a window and an unassigned approval outside the window. A Predictor Implementation Method for Data Recovery and Phase Monitoring of Networks. In the asynchronous transmission mode-passive optical branch network with a processor, The broadband station device (OLT) and the optical subscriber access device (ONU) are connected by using a passive optical element, and the transmission convergence layer function module is provided in the optical subscriber access device (ONU), and the predictor is provided in the transmission convergence layer function module. First function; A second function of identifying a characteristic of a cell into which the provided predictor flows upward; And According to the characteristics of the cell, after receiving the approval information from the delimiter and PRM (PLOAM, Ranging, Minislot) cell processor of the next cell and performing internal processing, the delimiter information and phase monitoring information to the data recovery unit Third function to provide A computer-readable recording medium having recorded thereon a program for realizing this.