WO2017113349A1

WO2017113349A1 - Data parsing and data transmission method and apparatus

Info

Publication number: WO2017113349A1
Application number: PCT/CN2015/100244
Authority: WO
Inventors: 景磊; 高波; 赵殿博
Original assignee: 华为技术有限公司
Priority date: 2015-12-31
Filing date: 2015-12-31
Publication date: 2017-07-06

Abstract

Provided is a data parsing method, comprising: an optical network unit (ONU) receiving a downlink data frame from an optical line terminal (OLT), wherein the downlink data frame comprises a first FEC codeword protected through first forward error correction (FEC) encoding and a second FEC codeword protected through second FEC encoding, the error correction capability of the second FEC encoding adopted by the second FEC codeword is stronger than that of the first FEC encoding adopted by the first FEC codeword, and the first FEC codeword comprises start position information about the second FEC codeword and end position information about the second FEC codeword; the ONU parsing the start position information and the end position information about the second FEC codeword from the first FEC codeword; and the ONU parsing the second FEC codeword determined according to the start position information and the end position information so as to acquire user data. By means of the data parsing method in the embodiments of the present invention, a bit error rate can be reduced, thereby improving the synchronization efficiency. Further provided are a corresponding data transmission method, a corresponding ONU and an OLT.

Description

Data analysis and data transmission method and device

Technical field

The present invention relates to the field of communications technologies, and in particular, to a data parsing and data transmission method and apparatus.

Background technique

The PON (Passive Optical Network) technology can greatly save fiber resources and has been widely used in the field of access. The PON network is generally composed of an OLT (Optical Line Termination), a POS (Passive Optical Splitter), and an ONU (Optical Network Unit).

The downlink data of the OLT to the ONU in the PON is broadcast to all ONUs in the working state in the form of frames. Each ONU parses all data after accepting the frame message and discards the data requested by other ONUs. Taking XGPON (10G-GPON, 10 Gigabit Passive Optical Network) as an example, XGPON's downlink data frame XGTC (XGPON transmission convergence, 10 Gigabit Passive Optical Network Transmission Convergence) frame is in accordance with FEC (Forward Error Correction, Forward) The error correction code block is required to be divided into a plurality of FEC code blocks, and the FEC coded information code block and the check bits of each FEC code block together constitute an FEC code word. A certain number of FEC codewords are combined into a payload to scramble the payload. The scrambled payload plus the fields used for synchronization together constitute a PHY (Physical Layer) frame of the XGPON downlink. After accepting the measured data, the data is first synchronized according to the synchronization field, then the payload portion is descrambled, and the starting position of the FEC is delimited to correctly parse the FEC encoding. Over time, the optical components of the XGPON system will age, making the link power budget tight, the bit error rate rising, and even failing to work properly. The synchronization difficulty will increase under high error codes, affecting customer satisfaction.

Summary of the invention

Embodiments of the present invention provide a data parsing method, including: an optical network unit ONU from an optical line The terminal OLT receives a downlink data frame, where the downlink data frame includes a first forward error correction FEC code protected first FEC codeword, and a second FEC code protected second FEC codeword, the second FEC codeword The error correction capability of the second FEC code used is stronger than the first FEC code used by the first FEC codeword, and the first FEC codeword includes the second FEC codeword start position information and the first Two FEC codeword end position information; the ONU parses the start position information and the end position information of the second FEC codeword from the first FEC codeword; the ONU parses the start location information and the location The second FEC codeword determined by the end location information is obtained to obtain user data.

The embodiment of the present invention further provides a data transmission method, including: an optical line terminal OLT generates a downlink data frame, where the downlink data frame includes a first forward error correction FEC code protected first FEC codeword, and a second FEC Encoding a protected second FEC codeword, the second FEC code used by the second FEC codec has a stronger error correction capability than the first FEC codeword used by the first FEC codeword, the first FEC code The word includes the second FEC codeword start position information and the second FEC codeword end position information; the OLT sends the downlink data frame to the optical network unit ONU.

An embodiment of the present invention further provides an optical network unit ONU, including: a receiving unit, configured to receive a downlink data frame from an optical line terminal OLT, where the downlink data frame includes a first forward error correction FEC code protection first FEC a codeword, and a second FEC code-protected second FEC codeword, wherein the second FEC code uses a second FEC coded error correction capability that is stronger than the first FEC codeword uses the first FEC code And the first FEC codeword includes the second FEC codeword start location information and the second FEC codeword end location information. a parsing unit, configured to parse starting position information and ending position information of the second FEC codeword from the first FEC codeword, and parse a second FEC determined according to the starting location information and the ending location information Codewords to get user data.

An embodiment of the present invention further provides an optical line terminal OLT, including: a data generating unit, configured to generate a downlink data frame, where the downlink data frame includes a first forward error correction FEC code protected first FEC codeword, and a second FEC code protected second FEC codeword, the second FEC code used by the second FEC code has a stronger error correction capability than the first FEC codeword used by the first FEC codeword, The first FEC codeword includes the second FEC codeword start location information and the second FEC codeword end location information, and the sending unit is configured to send the downlink data frame to the optical network unit ONU.

In the technical solution provided by the embodiment of the present invention, the data frame exchanged between the OLT and the ONU includes the first FEC coded first FEC codeword and the second FEC coded second FEC codeword, in the first FEC code. The start position information and the end position information of the second FEC codeword are saved in the word. Since the error correction capability of the second FEC code is stronger than the first FEC code, the technical solution of the embodiment of the present invention can reduce the bit error rate, thereby improving synchronization. effectiveness. At the same time, because there are two kinds of FEC coded FEC codewords, different users in the same PON can select the FEC coding mode according to the link quality, which can be compatible with users with different needs and improve user satisfaction.

DRAWINGS

For a fuller understanding of the invention, reference should be

1 is a schematic diagram of an embodiment of a PON.

FIG. 2 is a schematic structural diagram of a downlink data frame according to an embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a downlink data frame according to another embodiment of the present invention.

FIG. 4 is a schematic structural diagram of a part of a downlink data frame according to an embodiment of the present invention.

Figure 5 is a schematic illustration of an embodiment of a synchronous state machine.

FIG. 6 is a schematic structural diagram of a downlink data frame according to another embodiment of the present invention.

FIG. 7 is a flowchart of a data parsing method according to an embodiment of the present invention.

FIG. 8 is a structural diagram of an ONU according to an embodiment of the present invention.

FIG. 9 is a structural diagram of an OLT according to an embodiment of the present invention.

detailed description

It should be understood at the outset that although the implementation process of one or more embodiments is described below, the present invention The systems and/or methods involved may be implemented using any technique, whether or not currently known or present. The invention is not limited to the illustrative embodiments, the drawings and the techniques described below, including the exemplary designs and embodiments described and illustrated herein, which may be modified within the scope of the appended claims and their equivalents. .

1 shows an embodiment of a PON 100, which may be a system for providing "last mile" network access. The PON 100 can be a point-to-multipoint network, including an Optical Line Terminal (OLT) 110, a plurality of Optical Network Units (ONUs) 120, and an Optical Distribution Network (ODN). 130, wherein the ODN 130 can be coupled to the OLT 110 and the plurality of ONUs 120. For example, the OLT 110 may be located at a Central Office (CO), the plurality of ONUs 120 may be located at a plurality of customer premises, and the ODN 130 is disposed between the OLT 110 and the ONU 120. The PON 100 may be a communication network that does not require any active devices to implement data distribution between the OLT 110 and the ONU 120. Instead, the PON 100 can distribute data between the OLT 110 and the ONU 120 using passive optical devices in the ODN 130.

In one embodiment, the PON 100 may be a GPON system, downlink data may be broadcast at a rate of approximately 2.5 Gigabits per second (Gbps), and uplink data may be transmitted at a rate of approximately 1.25 Gbps. In another embodiment, the PON 100 can be an NGA system that can be configured to transmit data frames with greater reliability and efficiency and through greater bandwidth. For example, the PON 100 can be a 10 Gbps GPON (also known as XGPON) with a downstream bandwidth of approximately 10 Gbps and an upstream bandwidth of at least approximately 2.5 Gbps. In addition, other examples that may be applied to the PON 100 include: an asynchronous transmission mode passive optical network defined by the ITU-T G.983 standard. (Asynchronous transfer mode PON, APON) and broadband passive optical network (Broadband PON, BPON), GPON defined by ITU-T G.984 standard, Ethernet passive optical network (EPON PON, EPON) defined by IEEE 802.3ah standard Wavelength Division Multiplexed (WDM) Passive Optical Network (WPON), the entire contents of which are defined in the above-mentioned standards, are incorporated herein by reference.

In one embodiment, the OLT 110 may be any component for transferring data between the plurality of ONUs 120 and another network (not shown). In particular, the OLT 110 can act as a medium between the plurality of ONUs 120 and the other network described above. For example, the OLT 110 can forward data received from the other network to the plurality of ONUs 120 and forward data received from the plurality of ONUs 120 to the other network. Although the specific configuration of the OLT 110 may vary depending on the particular type of PON 100, in one embodiment, the OLT 110 may include a transmitter and a receiver. If the network protocol used by the other network is different from the PON protocol used by the PON 100, for example, the other network uses an Ethernet protocol or a Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) protocol, the OLT 110. A converter may be further included for converting the above network protocol into a PON protocol. Moreover, the converter of the OLT 110 can also convert the PON protocol into the above network protocol. The OLT 110 is typically located at a central location, such as a central office, but may be located at other locations as well.

In one embodiment, the plurality of ONUs 120 can be any device for communicating with the OLT 110 and a customer or user (not shown). In particular, the plurality of ONUs 120 can act as a medium between the OLT 110 and the user. For example, the plurality of ONUs 120 can forward data received from the OLT 110 to the user and forward data received from the user to the OLT 110. Although the specific configuration of the plurality of ONUs 120 may vary depending on the particular type of PON 100, in one embodiment, the ONUs 120 may include a light for transmitting optical signals to the OLT 110. A transmitter and a receiver for receiving optical signals from the OLT 110. Furthermore, the ONU 120 may further comprise a converter for converting an optical signal into an electrical signal for a user, such as a signal based on an Ethernet protocol or an ATM protocol; and another transmitter and/or receiver for the The user transmits and/or receives an electrical signal from the user. In some embodiments, the ONU 120 is similar to an Optical Network Terminal (ONT), and thus, the ONU and the ONT are interchangeable in this document. Typically, the plurality of ONUs may be located in a distributed location, such as a customer premises, but may be located elsewhere.

In one embodiment, the ODN 130 can be a data distribution system that can include fiber optic cables, couplers, splitters, distributors, and/or other devices. In one embodiment, the fiber optic cable, coupler, splitter, distributor, and/or other device may be a passive optical device. In particular, the fiber optic cable, coupler, splitter, distributor, and/or other device may be a device that does not require a power source when distributing data signals between the OLT 110 and the plurality of ONUs 120. Alternatively, the ODN 130 may also include one or more processing devices, such as optical amplifiers. In the branching structure as shown in FIG. 1, the ODN 130 may specifically extend from the OLT 110 to the ONU 120, but may also be configured in other point-to-multipoint configurations.

In one embodiment, the OLT 110 and the ONU 120 may perform data exchange, and the data may be encapsulated in a frame or message, such as an Ethernet frame. The frame may include a payload and a frame header, wherein the frame header may include synchronization and configuration information. For example, a Transmission Convergence (TC) frame can be used to transmit a downlink message based on the GPON Transmission Aggregation (GTC) protocol layer. Information, such as from the OLT 110 to the ONU 120. The transport convergence layer is defined in the ITU-T G.984.3 standard, the contents of which are incorporated herein by reference. The TC may also include a Physical Synchronization (Psync) field, which may indicate the beginning of the TC frame. Typically, the Psync field may include a fixed code, which may have a fixed code value of "0xB6AB31E0" (hexadecimal format) to indicate the beginning of the frame. The field can be equal to approximately four bytes (Bytes). The OLT 110 or the receiver of the ONU 120 may delimit the frame using the Psync field in the received frame, such as separating or distinguishing the frames.

2 illustrates an embodiment of a frame 200 that may include FEC encoded control and/or user data and synchronization information. For example, frame 200 may correspond to a GTC or XGTC frame, such as a downstream frame from OLT 110 to ONU 120, and may be transmitted within a fixed time window. Frame 200 can include a first portion 210 and a second portion 211. The first portion 210 can correspond to a GTC or XGTC PCBd or header and can include time or synchronization information.

The second portion 211 can correspond to a GTC or XGTC payload and can include a plurality of codewords that may be FEC encoded. For example, the second portion 211 can include an integer number of FEC code words. The downlink data frame XGTC frame is divided into a plurality of FEC information code blocks according to the FEC code block requirement, and the FEC coded information code block and the check bit (P) of each FEC code block together constitute an FEC code word. A certain number of FEC codewords are combined into a payload of 125us PHY Frame and scrambled. The scrambled PHY frame payload plus the field psbd for synchronization together form the PHY frame of the XGPON downlink. After accepting the measured data, the data synchronization is first performed according to the PSBD, then the payload portion is descrambled, and the starting position of the FEC is delimited to correctly parse the FEC encoding.

3 illustrates an embodiment of a frame 300, which may be a downstream GTC or XGTC frame, which may include FEC encoded control and/or user data and synchronization information. The first part 310 and FIG. 2 The first portion 210 is similar and will not be described in detail herein. The second portion 311 can correspond to a GTC or XGTC payload and can include a plurality of codewords that may be FEC encoded. For example, the second portion 311 can include an integer number of FEC code words. The GTC or XGTC payload may include a payload length downstream (Plend) 312, an upstream bandwidth map (US BWmap) 314, at least one physical layer operation, management and maintenance (PLOAM) field 316, and a payload 318. Plend 312 may include multiple subfields including B length (Blen) and cyclic redundancy check (CRC). Blen may indicate the length of the US BWmap 314, for example in bytes. The CRC can be used, for example, to verify at the ONU 120 whether there is an error in the received frame 300. For example, when the CRC fails, frame 300 can be discarded. In some PON systems that support asynchronous transfer mode (ATM) communication, the subfield may also include an A length subfield that indicates the length of the ATM payload, which may include a portion of frame 300. The US BWmap 314 can include an array of blocks or subfields, each of which can include a single bandwidth allocation to a single transmitter (TC) that can be used to manage upstream bandwidth allocations in the GTC layer. The TC may be a transport entity in the GTC layer that may be configured to communicate higher layer information from the input to the output, such as from the OLT to the ONU. Each block in BWmap 314 may include multiple subfields, such as an allocation identifier (Alloc-ID), a flag, a start time (SStart), a stop time (SStop), a CRC, or a combination of the above.

The PLOAM field 316 can include a PLOAM message that can be sent from the OLT to the ONU and includes an Operation, Management and Maintenance (OAM) related alarm or a threshold violation alarm triggered by a system event. The PLOAM field 316 can include multiple subfields, such as an ONU identifier (ONU-ID), a message identifier (message ID), message data, and a CRC. The ONU-ID may include an address that may be assigned to one of the ONUs and used by the ONU to detect its intended message. The message ID may indicate the type of PLOAM message and the message data may include the payload of the PLOAM message. The CRC can be used to verify if there is an error in the received PLOAM message. For example, when the CRC fails, the PLOAM message can be discarded. Frame 300 may include different PLOAMs 316 corresponding to different ONUs, which may be indicated by different ONU-IDs. Payload 318 can include broadcast data (eg, User data). For example, payload 318 can include a GPON encapsulation method (GEM) payload.

FIG. 4 illustrates another embodiment of a frame portion 400 that may include synchronization information. For example, frame portion 400 may correspond to a PSBd in a downstream GTC or XGTC frame. The PSBd 410 can include a PSync mode 412, a superframe structure 414, and a PON-ID structure 420. In an embodiment, frame portion 200 or PSBd may include approximately 24 bytes, wherein each of Psync mode 412, superframe structure 414, and PON-ID structure 420 may include approximately eight bytes. Moreover, each of superframe structure 414 and PON-ID structure 420 can include HEC encoding that can be used to detect/correct errors in corresponding fields.

PSync mode 412 can be used to detect the beginning of a PSBd in a frame and can include approximately 64 bits. The ONU can use PSync mode 412 to align frames on downstream frame boundaries. The PSync mode 412 can include a fixed mode, such as 0xC5E51840FD59BB49. Superframe structure 414 can include superframe counter 416 and HEC code 418. Superframe counter 416 may correspond to approximately 51 most significant bits of superframe structure 414 and may specify the order of the downstream frames transmitted. For each downstream (XGTC or GTC) frame, superframe counter 416 may include a value greater than the previously transmitted downstream frame. When the superframe counter 316 reaches a maximum value, the subsequent superframe counter 316 in subsequent downstream frames may be set to approximately zero. The HEC code 418 may correspond to approximately the 13 least significant bits of the superframe structure 414 and may be configured in a manner substantially similar to the HEC field described above. HEC code 418 may be a combination of a BCH code that operates on approximately 63 initial bits of a frame header and a single parity bit.

The PON-ID structure 420 can include a PON-ID 422 and a second HEC code 424. PON-ID 422 may correspond to approximately 51 bits of PON-ID structure 420, and the HEC code may correspond to the remaining approximately 13 bits. The PON-ID 422 can be set by the OLT and used by the ONU to detect a protection switching event or to generate a security key. The configuration of the second HEC code 424 can be substantially similar to the HEC field described above. In particular, HEC code 418 can be used to detect/correct errors in superframe counter 416, and second HEC code 424 can be used to detect/correct errors in PON-ID 422.

Since the synchronization information can be encapsulated in a plurality of additional bytes that are not FEC encoded in the downstream frame, the HEC code can be added to the synchronization information in the additional bytes as described in the frame portion 300 or the frame portion 400, To provide sufficient or acceptable error detection/correction capabilities for synchronizing information at the ONU. In many cases, this HEC coding scheme can provide efficient error detection/correction. For example, when the ONU is in a deep sleep situation, the ONU can relock to the OLT at each particular time period (eg, every approximately 10 microseconds). Thus, in the case of a false lock, multiple errors may occur in additional bytes (eg, approximately 24 bytes) that are not subject to FEC encoding. However, with the HEC code in the extra bytes, the probability of preventing or resolving these errors can be quite high.

FIG. 5 illustrates an embodiment of a synchronization state machine 500 that can be used by an ONU to synchronize downstream transmission frames, such as frame 200. Synchronization state machine 500 may use a PSync mode in the downstream frame that may not be FEC encoded, such as PSync mode 312 or PSync mode 412. The PSync mode may be located in a portion of the downstream frame, such as PSBd, frame portion 300, or first portion 210. The specific format of the PSBd frame may refer to FIG. In some embodiments, the PSync mode may be protected by HEC code, such as HEC fields.

The ONU can implement the synchronization state machine 500, for example, using software, hardware, or both. Synchronization state machine 500 can begin in a seek state 510 where a search for PSync mode can be performed in all possible alignments (eg, bit and/or byte alignment). If the correct PSync mode is found, the synchronization state machine 500 can transition to a Pre-Sync state 520 in which a fixed length of time (eg, approximately 125 microseconds) can be performed after the last detected PSync mode. Search for the second PSync mode. If the second PSync mode is not successfully found in the pre-synchronization state 520, the synchronization state machine 500 can return from the pre-synchronization state 520 to the seek state 510. If the second PSync mode is successfully found in the pre-synchronization state 520, the synchronization state machine 500 can transition to the Sync state 530. If the synchronization state 530 is reached, the synchronization state machine 500 can announce that the downstream frames are successfully synchronized, and then begin processing the frames. In an embodiment, if the ONU detects M consecutive incorrect PSync fields or modes (M is an integer), the synchronization state machine 500 may declare that the synchronization of the downstream frame was unsuccessful and return to the seek state 510. For example, M can be equal to two.

The GTC frame and the XGTC frame are mentioned above. The XGTC frame is taken as an example. The structure of the XGTC frame can be referred to FIG. 3. Meanwhile, those skilled in the art should understand that the GTC frame can also be applied to the data parsing method of the present invention. When the FEC codeword in the XGTC frame protects the FEC codeword using only the existing FEC code, the XGPON system optical device (including the active device and the passive device) will age over time, making the link power budget Tension, the bit error rate rises, and the difficulty of the state machine from the search state to the synchronization state increases under high error. One solution is to upgrade the device. However, the degradation of different users under the same passive optical network is different, and the quality of the user link is very different. The unified device upgrade will generate a large waste and increase the investment pressure of the customer. In order to improve the utilization of the existing device while shortening the synchronization time, the first FEC codeword in the XGTC frame can be protected by using the existing first FEC code, and the error correction capability is stronger than the first FEC code. Two FEC encodings to protect the second FEC codeword in the XGTC frame. There may be multiple first FEC codewords in the first FEC encoded protected XGTC frame, and multiple second FEC codewords in the XGTC frame protected by the second FEC encoding.

FIG. 6 is a format of an XGTC frame according to an embodiment of the present invention. Unlike the XGTC frame format of FIG. 2, the XGTC frame includes first

FEC code words

614 and 618 protected by a first FEC coded RS (248, 216). In addition, second FEC code protected second

FEC code words

622 and 626 that are stronger than the first FEC encoding error correction capability are also included. In the area protected by the first FEC encoding, the specified location join pointer indicates the start and end position of the second FEC codeword encoded by the second FEC, the finger It is visible to all ONUs protected by the second FEC encoding, and is invisible to the ONUs protected by the first FEC encoding, that is, only the ONUs protected by the second FEC encoding can parse the second FEC codewords, using the first FEC encoding. The protected ONU does not have the function of parsing the second FEC codeword. The location where the pointer is stored includes, but is not limited to, the following fields: a profile message field in the PLOA message, a new field in the BWmap, and a fixed position of the last first FEC codeword in each frame.

It should be noted that the ONU protected by the second FEC code can parse the first FEC codeword in addition to the second FEC codeword. The ONU protected by the second FEC code is wired according to the following steps:

The ONU protected by the second FEC encoding is synchronized according to the state machine described in FIG. 5, wherein the value of M can be increased from 2 to 6, and the fault tolerant bit of Psync can be increased from 2 to 4. The ONU protected by the second FEC encoding parses the first FEC codeword, and acquires pointer information from the first FEC codeword. For this ONU link, the message may be incorrect due to insufficient protection of FEC encoding. Confirmation is carried out in a consistent manner for four consecutive receptions. The ONU protected by the second FEC code confirms that the second FEC codeword is parsed after the start and end of the second FEC codeword, and the second FEC codeword is included in the XGTC frame that the second FEC coded protected ONU interacts with the OLT. A second FEC codeword may also include start location information and end location information of other second FEC codewords, such that the second FEC code-protected ONU that normally goes online may obtain other second FEC codes from the second FEC codeword. The start position information and the end position information of the word, since the probability of the error of the second FEC code word is lower than the first FEC code word, the position information can be resolved from the second FEC code word more quickly and accurately.

Since the second FEC-protected ONU adopts a multiple-received acknowledgment mode when acquiring the pointer information, the start and stop positions (starting position and ending position) of the second FEC codeword required for the second FEC encoding cannot occur every frame. Change, that is, the position of the second FEC codeword cannot be One frame changes, but the adjustment is made as needed to maintain the starting and ending position to the next adjustment.

In another embodiment of the present invention, in the area protected by the first FEC-encoded RS (248, 216), the designated location is added to the pointer, which is visible to all ONUs protected by the second FEC encoding, and protected by the first FEC encoding. The ONU is not visible, and the pointer content is used to indicate the ONUID of the ONU protected by the second FEC encoding and the start and end position of the second FEC codeword encoded by the second FEC. A pointer is added in the area protected by the second FEC code, and the pointer is visible to all ONUs that are encoded by the second FEC, and is used to indicate start position information and end position information of the second FEC code word of the next frame. The location where the pointer is stored includes, but is not limited to, the following fields: an attribute message field in the PLOAM message, a new field in the BWmap, and a fixed position of the last first FEC codeword in each frame.

As with the previous embodiment, the ONU protected by the second FEC encoding can parse the first FEC codeword in addition to the second FEC codeword. The ONU protected by the second FEC code is uplinked according to the following steps: the ONU protected by the second FEC code is synchronized according to the state machine described in FIG. 5, wherein the value of M can be increased from 2 to 6, and the fault tolerance bit of Psync can be 2 increased to 4. The ONU protected by the second FEC encoding receives an XGTC frame from the OLT, the XGTC frame includes a first FEC codeword, the ONU protected by the second FEC encoding parses the first FEC codeword, and obtains a pointer from the first FEC codeword information. For this ONU link, the message may be incorrect due to insufficient FEC protection. Different from the previous embodiment, here, the ONU protected by the second FEC encoding adopts a method of attempting to go online, and the second FEC codeword is correctly parsed as long as the start position information and the end position information of the second FEC codeword are correctly found once. After that, the start position information and the end position information of the second FEC code word can be found.

The ONU protected by the second FEC code confirms the start position information and the end position information of the second FEC codeword, and then parses the second FEC codeword included in the XGTC frame that the ONU interacts with the OLT to Get user data.

A second FEC codeword may also include start location information and end location information of other second FEC codewords, such that the second FEC code-protected ONU that normally goes online may obtain other second FEC codes from the second FEC codeword. The start position information and the end position information of the word, since the probability of the error of the second FEC code word is lower than the first FEC code word, the position information can be resolved from the second FEC code word more quickly and accurately.

Since the ONU protected by the second FEC code does not adopt the multiple-acknowledgment confirmation mode when acquiring the pointer information, the start position and the end position of the second FEC codeword of each XGTC frame are not required to be the same, and the real-time performance is improved.

It should be noted that the frame structure is exemplarily explained here by XGTC, and the above description of the XGTC frame is also applicable to the GTC frame.

FIG. 7 is a schematic diagram of a data parsing method according to an embodiment of the present invention, the method includes:

S710. The ONU receives a downlink data frame from the OLT, where the downlink data frame includes a first FEC codeword protected by the first FEC encoding, and a second FEC codeword protected by the second FEC encoding.

Here, the format of the downlink data frame can refer to FIG. 3, and the ONU can parse the second FEC codeword and parse the first FEC codeword. The error correction capability of the second FEC code used by the second FEC codeword is stronger than the first FEC code used by the first FEC codeword, and the first FEC codeword includes the second FEC codeword. Location information and the second FEC codeword end location information.

S720: The ONU parses the start position information and the end position information of the second FEC codeword from the first FEC codeword.

Since the ONU has the ability to parse the first FEC codeword, the ONU parses the start location information and the end location information of the second FEC codeword from the first FEC codeword. The second FEC codeword start location information and the second FEC codeword end location information may be located in an attribute message field in a PLOAM message of the downlink data frame, where The field added in the row data frame BWmap message, or the pre-set position of the last first FEC codeword in the downlink data frame.

The first FEC codeword includes a Psync field of 64 bits in length. As shown in FIG. 4, the Psync field may be part of the PSBd, and the ONU receives the downlink data frame, and parses the first FEC of the downlink data frame. Before the codeword, the method further includes: the ONU searches for the Psync field included in the first FEC codeword, and after matching the M1 Psync fields, confirms that the downlink data frame is synchronized, and the Psync field of the first FEC codeword The matching includes matching N1 bits in the Psync field of the first FEC codeword. Here, the value of M1 may take 2, and the value of N1 may take 62, that is, the fault-tolerant bit of the Psync field of the first FEC codeword is 2 bits. In order to ensure the accuracy of the start position information and the end position information of the second FEC codeword, the ONU may parse from the plurality of first FEC codewords, and the start position information and the end position information of the parsed second FEC codeword are both When the same, the position of the second FEC code word is determined based on the start position information and the end position information.

S730. The ONU parses the second FEC codeword determined according to the start location information and the end location information to acquire user data.

The ONU can locate the second FEC codeword according to the start location information and the end location information of the second FEC codeword, and can obtain the user data after parsing the second FEC codeword.

Here, the second FEC codeword may include a Psync field of 64 bits in length, and before the ONU parses the second FEC codeword, the method further includes: the ONU reading a Psync field included in the second FEC codeword, After matching the M2 Psync fields, parsing the second FEC codeword according to the start position and the end position of the second FEC codeword to obtain user data, and the matching of the Psync field of the second FEC codeword includes matching N2 bits in the Psync field of the second FEC codeword, the M2 is greater than M1, and the N2 is less than N1. Here, the value of M2 may be 6, and the value of N2 may be 60, that is, the error-tolerant bit of the Psync field of the second FEC codeword is 4 bits.

Optionally, the data parsing method of the embodiment of the present invention may further include the following steps:

S740. The ONU acquires start position information and a knot of the other second FEC codeword from the second FEC codeword. Beam position information;

S750. The ONU parses the second FEC codeword determined according to the start location information and the end location information of the other second FEC codewords to obtain user data.

Here, the ONU determines the other second FEC codewords according to the start location information and the end location information of the other second FEC codewords, and parses the other second FEC codewords to obtain user data.

In the technical solution of the embodiment of the present invention, the data frame exchanged between the OLT and the ONU includes the first FEC coded first FEC codeword and the second FEC coded second FEC codeword, in the first FEC codeword. The start location information and the end location information of the second FEC codeword are saved. Since the error correction capability of the second FEC encoding is stronger than the first FEC encoding, the technical solution of the embodiment of the present invention can reduce the error rate and improve the synchronization efficiency. . At the same time, because there are two kinds of FEC coded FEC codewords, different users in the same PON can select the FEC coding mode according to the link quality, which can be compatible with users with different needs and improve user satisfaction.

FIG. 8 is a structural diagram of an ONU according to an embodiment of the present invention, where the ONU includes:

The receiving unit 810 is configured to receive, by the OLT, a downlink data frame, where the downlink data frame includes a first FEC code protected first FEC codeword, and a second FEC code protected second FEC codeword, the second FEC code The error correction capability of the second FEC code used by the word is stronger than the first FEC code used by the first FEC codeword, and the first FEC codeword includes the second FEC codeword start position information and The second FEC codeword end position information is described.

The parsing unit 820 is configured to parse the start location information and the end location information of the second FEC codeword from the first FEC codeword, and parse the second determined according to the start location information and the end location information FEC codeword to get user data.

The second FEC codeword start location information and the second FEC codeword end location information may be located in an attribute message field in a PLOAM message of the downlink data frame, where the downlink data frame BWmap message is An added field, or a pre-set position of the last first FEC codeword in the downstream data frame.

The ONU may further include a search unit 830, where the first FEC codeword may include a physical synchronization Psync field of length 64 bits before the parsing unit 820 parses the first FEC codeword of the downlink data frame The search unit 830 searches for the Psync field included in the first FEC codeword, and after matching the M1 Psync fields, confirms that the downlink data frame is synchronized, and the matching of the Psync field of the first FEC codeword includes matching N1 bits in the Psync field of the first FEC codeword.

The second FEC codeword may also include a physical synchronization Psync field of 64 bits. Before the parsing unit 820 parses the second FEC codeword, the searching unit 830 may be further configured to: read the second FEC codeword. The Psync field includes, after matching the M2 Psync fields, parsing the second FEC codeword according to the start position and the end position of the second FEC codeword to obtain user data, and the PSF of the second FEC codeword The matching of the fields includes matching N2 bits in the Psync field of the second FEC codeword, the M2 being greater than M1, and the N2 being less than N1.

The receiving unit 810 of the embodiment of the present invention may be a receiver, the parsing unit 820 may be a decoder, and the function of the searching unit 830 may be implemented by a processor.

FIG. 9 is a structural diagram of an OLT according to an embodiment of the present invention, where the OLT includes:

The data generating unit 910 is configured to generate a downlink data frame, where the downlink data frame includes a first forward error correction FEC code protected first FEC codeword, and a second FEC code protected second FEC codeword, where The error correction capability of the second FEC code used by the second FEC codeword is stronger than the first FEC code used by the first FEC codeword, and the first FEC codeword includes the start position of the second FEC codeword Information and the second FEC codeword end location information;

The sending unit 920 is configured to send the downlink data frame to the optical network unit ONU.

The second FEC codeword in the downlink data frame generated by the data generating unit 910 may include start location information and end location information of other second FEC codewords.

Here, the data generating unit 910 may be a framer, and the transmitting unit 920 may be a Transmitter.

A person skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the system, the device and the unit described above can refer to the corresponding process in the foregoing method embodiment, and details are not described herein again.

In the several embodiments provided by the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a standalone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, or all or part of the technical solution, may be embodied in the form of a software product stored in a storage medium. A number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like. .

The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the embodiments are modified, or the equivalents of the technical features are replaced by the equivalents of the technical solutions of the embodiments of the present invention.

Claims

A data analysis method, comprising:

The optical network unit ONU receives a downlink data frame from the optical line terminal OLT, where the downlink data frame includes a first FEC codeword encoded with a first forward error correction FEC, and a second FEC codeword encoded with a second FEC. The error correction capability of the second FEC code is stronger than the error correction capability of the first FEC code, and the first FEC codeword includes the second FEC codeword start position information and the second FEC codeword End position information;

Determining, by the ONU, start position information and end position information of the second FEC codeword from the first FEC codeword;

The ONU determines a second FEC codeword according to the start location information and the end location information, and parses the second FEC codeword to obtain user data.
The data analysis method according to claim 1, wherein:

The second FEC codeword includes start location information and end location information of other second FEC codewords, and the ONU determines the other second according to start location information and end location information of the other second FEC codewords The FEC codeword parses the other second FEC codewords to obtain user data.
The data analysis method according to claim 1 or 2, characterized in that

The second FEC codeword start location information and the second FEC codeword end location information are located in an attribute message field in a PLOAM message of the downlink data frame, an added field in the downlink data frame BWmap message, or the The pre-set position of the last first FEC codeword in the downlink data frame.
The data parsing method according to any one of claims 1 to 3, wherein the first FEC codeword includes a physical synchronization Psync field having a length of 64 bits, and the ONU receives the downlink data frame. Before parsing the first FEC codeword of the downlink data frame, the method further includes: searching, by the ONU, a Psync field included in the first FEC codeword, after matching the M1 Psync fields, confirming the downlink Data frame synchronization, matching packet of the Psync field of the first FEC codeword The N1 bits in the Psync field of the first FEC codeword are matched.
The data parsing method according to claim 4, wherein the second FEC codeword includes a physical synchronization Psync field of 64 bits in length, and the ONU further includes: before the parsing the second FEC codeword The ONU reads the Psync field included in the second FEC codeword, and after matching the M2 Psync fields, parses the second FEC codeword according to the start position and the end position of the second FEC codeword to obtain User data, the matching of the Psync field of the second FEC codeword includes matching N2 bits in the Psync field of the second FEC codeword, the M2 being greater than M1, and the N2 being less than N1.
The data parsing method according to any one of claims 1 to 5, wherein the ONU determines the second FEC code according to the start position information of the second FEC codeword and the end position information. Before the word, the method includes:

The ONU parses the start position information and the end position information of the same second FEC codeword from the plurality of the first FEC codewords.
An optical network unit ONU, comprising:

a receiving unit, configured to receive a downlink data frame from the optical line terminal OLT, where the downlink data frame includes a first FEC codeword encoded by a first forward error correction FEC, and a second FEC codeword encoded by a second FEC, The error correction capability of the second FEC code is stronger than the error correction capability of the first FEC code, where the first FEC codeword includes the second FEC codeword start position information and the second FEC code Word end position information;

a parsing unit, configured to parse starting position information and ending position information of the second FEC codeword from the first FEC codeword, and parse a second FEC determined according to the starting location information and the ending location information Codewords to get user data.
The ONU according to claim 7, wherein the second FEC codeword start location information and the second FEC codeword end location information may be attribute message fields in a PLOAM message of the downlink data frame, The field added in the downlink data frame BWmap message, or the downlink The pre-set position of the last first FEC codeword in the data frame.
The ONU according to claim 7 or 8, wherein the first FEC codeword comprises a physical synchronization Psync field of length 64 bits, the ONU further comprising a search unit, the search unit is configured to Before parsing the first FEC codeword of the downlink data frame, the parsing unit searches for a Psync field included in the first FEC codeword, and after matching the M1 Psync fields, confirms that the downlink data frame is synchronized. The matching of the Psync field of the first FEC codeword includes matching N1 bits in the Psync field of the first FEC codeword.
The ONU according to claim 9, wherein the second FEC codeword comprises a physical synchronization Psync field of 64 bits in length, and the searching unit is further configured to: parse the second FEC codeword in the parsing unit Having previously read the Psync field included in the second FEC codeword, after matching the M2 Psync fields, parsing the second FEC codeword according to the start position and the end position of the second FEC codeword to obtain User data, the matching of the Psync field of the second FEC codeword includes matching N2 bits in the Psync field of the second FEC codeword, the M2 being greater than M1, and the N2 being less than N1.
A data transmission method, comprising:

The optical line terminal OLT generates a downlink data frame, where the downlink data frame includes a first forward error correction FEC code protected first FEC codeword, and a second FEC code protected second FEC codeword, the second FEC code The error correction capability of the second FEC code used by the word is stronger than the first FEC code used by the first FEC codeword, and the first FEC codeword includes the second FEC codeword start position information and Describe a second FEC codeword end location information;

The OLT sends the downlink data frame to the optical network unit ONU.
A data transmission method according to claim 11, wherein:

The second FEC codeword includes start location information and end location information of other second FEC codewords, and the ONU determines the other second according to start location information and end location information of the other second FEC codewords The FEC codeword parses the other second FEC codewords to obtain user data.
A data transmission method according to claim 11 or 12, wherein:

The second FEC codeword start location information and the second FEC codeword end location information are located in an attribute message field in a PLOAM message of the downlink data frame, an added field in the downlink data frame BWmap message, or the The pre-set position of the last first FEC codeword in the downlink data frame.
An optical line terminal OLT, comprising:

a data generating unit, configured to generate a downlink data frame, where the downlink data frame includes a first forward error correction FEC code protected first FEC codeword, and a second FEC code protected second FEC codeword, the second The error correction capability of the second FEC code used by the FEC codeword is stronger than the first FEC code used by the first FEC codeword, and the first FEC codeword includes the second FEC codeword start position information. And ending the location information with the second FEC codeword;

And a sending unit, configured to send the downlink data frame to the optical network unit ONU.
The OLT according to claim 14, wherein the second FEC codeword in the downlink data frame generated by the data generating unit includes start location information and end location information of other second FEC codewords.