WO2018165893A1 - 一种光网络单元发送光信号的方法及光网络单元 - Google Patents

一种光网络单元发送光信号的方法及光网络单元 Download PDF

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Publication number
WO2018165893A1
WO2018165893A1 PCT/CN2017/076727 CN2017076727W WO2018165893A1 WO 2018165893 A1 WO2018165893 A1 WO 2018165893A1 CN 2017076727 W CN2017076727 W CN 2017076727W WO 2018165893 A1 WO2018165893 A1 WO 2018165893A1
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indication information
codeword
data
code block
laser
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PCT/CN2017/076727
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English (en)
French (fr)
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殷锦蓉
赵殿博
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华为技术有限公司
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Priority to PCT/CN2017/076727 priority Critical patent/WO2018165893A1/zh
Publication of WO2018165893A1 publication Critical patent/WO2018165893A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/50—Transmitters

Definitions

  • the present application relates to the field of optical communications, and in particular, to an optical network unit (ONU) and a method for transmitting an optical signal by an optical network unit.
  • ONU optical network unit
  • Passive Optical Network is a point-to-multipoint network topology, which usually includes an Optical Line Terminal (OLT) at the Central Office (CO) and multiple users at the user end.
  • OLT Optical Line Terminal
  • ONU optical network unit
  • ODN optical distribution network
  • the current standards for PON access technologies mainly include IEEE series standards such as EPON and 10G-EPON standards, and International Telecommunication Union (ITU) such as GPON, XG-EPON, XGS-PON and TWDM-PON. ) series of standards.
  • ITU International Telecommunication Union
  • 1 shows a network structure of an existing EPON.
  • the EPON 100 may include an optical line terminal (OLT) 110, an optical distribution network 120 (ODN), and at least one optical network unit (ONU) 130, OLT 110. Communication with at least one ONU 130 is through ODN 120.
  • the OLT to the ONU is called the downstream direction.
  • the OLT assembles the downlink services that are delivered to the respective ONUs into frames and sends them to multiple ONUs in broadcast mode. That is, the splitter is divided into N independent signals, and each ONU extracts only the frame sent to itself. Downlink transmission supports continuous operation mode. From the ONU to the OLT is called the upstream direction.
  • the uplink data of each ONU to the OLT is transmitted through a shared channel of Time Division Multiple Access (TDMA) mode, and the OLT allocates one uplink transmission time slot for each ONU.
  • TDMA Time Division Multiple Access
  • the EPON system is a point (OLT) to multipoint (ONU) network structure.
  • Each ONU cannot send uplink data to the OLT at the same time.
  • An ONU can only send data to the OLT through the laser in the authorized time slot allocated to itself. Therefore, the uplink data transmission adopts a Burst mode of operation. That is, the ONU sends uplink data to the OLT burst according to the uplink grant time. It can be seen from the above that the ONU laser is turned on when bursting uplink data.
  • 100G EPON is a next-generation EPON system for 10G EPON.
  • the physical layer of the EPON architecture can only achieve a maximum rate of 25 Gbps.
  • four 25 Gbps channels need to be bound to carry 100 Gbps of original data streams.
  • the OLT distributes the data packets of one original data stream to four channels for transmission, and the ONU needs to receive the data packets from four channels, and four The data packets of the channel are reorganized to form a raw data stream.
  • the ONU distributes the data packets of one original data stream to four channels for transmission, and the OLT needs to receive the data packets from four channels, and reassembles the data packets of four channels to form one original data. flow.
  • a commonly used data transmission method is: a Reconciliation Sublayer (RS) forward error correction (FEC) codeword unit, and the transmission data is mapped on different channels.
  • RS Reconciliation Sublayer
  • FEC forward error correction
  • the ONU's Harmonic Sublayer (RS) needs rate matching and may be in the header of one or more data streams. Insert an idle code block.
  • the physical coding sublayer (PCS) triggers the laser to be turned on only when a valid data block is detected. If the data in the first FEC codeword in the data stream(s) starts with an idle code block, the laser may not be turned on in time according to the grant time on the channel corresponding to the data stream(s). .
  • the embodiment of the invention provides a method for transmitting an optical signal by an ONU and an optical network unit of an optical network unit, which can enable the ONU to turn on the laser in time when transmitting the uplink data stream, and does not need to change the code block format defined in the existing EPON standard. And the related code block processing flow is simple and effective to implement.
  • a method for an optical network unit to transmit an optical signal may include: the ONU generating, according to the authorized time slot information, a data code stream corresponding to each channel, where the data stream in each channel is in the data stream.
  • the first codeword carries the first indication information.
  • the ONU When the first indication information in the data stream is detected, the ONU generates a message indicating that the optical module turns on the laser.
  • the first indication information may be used to indicate a first codeword in the data code stream.
  • the ONU can turn on the laser in time when transmitting the data stream, and avoid changing the code block format and the related code block processing flow defined in the existing standard, and the implementation is simple and effective.
  • the embodiment of the present invention provides the following two implementation manners.
  • the first indication information such as a newly defined XGMII control word, is carried by a check code placeholder of the first codeword. It should be noted that the example is only an implementation manner of the embodiment of the present invention. In an actual application, the first indication information may also be other information, such as a newly defined special code block, which is not limited herein.
  • the check code may be an FEC check code, such as the last four 66-bit FEC check codes in the FEC codeword in the EPON standard, and the check code may also be other types of check codes. .
  • a special code block (distinguished from the code block format defined by the existing standard) is defined, and the first indication information is carried by including the special code block in the first code word.
  • the special code block may be referred to as a first designated code block.
  • the first designated code block may be the first code block of the first codeword.
  • the first designated code block may also be an intermediate code block of the first codeword, or may be a last code block of the first codeword.
  • the embodiment of the present invention is not limited.
  • the first designated code block may include a Logical Link Identity (LLID) of the ONU and a sequence number SN of the first codeword in the original data stream.
  • the LLID can be used to identify the ONU, that is, which ONU is generated or sent by the identification data frame.
  • the first designated code block may be combined using a reserved control word (such as reserved control word "/K/"), LLID, and SN in the existing EPON standard. It should be noted that the present application does not limit the combination order of the reserved control words, LLIDs, and SNs, and the number of bytes occupied by each.
  • the first designated code block may include a plurality of reserved control words.
  • the first designated code block may further include other information.
  • the last codeword in the data stream may further carry second indication information for identifying the last codeword.
  • the second indication information may be carried by a check code placeholder of the last codeword.
  • the ONU can turn off the laser according to the second indication information. Specifically, when a package is detected When the second indication information is included, the ONU may generate a message indicating that the optical module turns off the laser, thereby triggering the laser to be turned off.
  • the second indication information may be a newly defined XGMII control word, or may be an XGMII control word reserved in an existing standard, or may be other types of indication information, such as a new definition.
  • the special code block is not limited here. It can be understood that the first indication information is different from the second indication information, so as to facilitate distinguishing between the start and the end of the data stream.
  • the first indication information may also be carried in a payload of the first codeword
  • the second indication information may also be carried in a payload of the last codeword (payload) )in.
  • the check code placeholder of the first codeword may also be used to carry the quantity information of the codewords included in the data code stream, that is, the third indication information.
  • the ONU can also determine whether the codewords in the data stream are all transmitted according to the quantity information, and if the transmission is completed, trigger the laser to be turned off.
  • the laser can be turned off by the primitive PMA_SIGNAL.request(false).
  • the third indication information may also be carried in a payload of the first codeword.
  • the last codeword in the data stream transmitted on a single channel may include a second designated code block for carrying the second indication information.
  • the ONU can turn off the laser according to the second designated code block.
  • the ONU may generate a message indicating that the optical module turns off the laser, thereby triggering the laser to be turned off.
  • the second designated code block is a special code block newly defined in the embodiment of the present invention, and is used to represent the second indication information, indicating the last codeword. That is, the codeword containing the second designated code block is the last codeword in the data stream. Similar to the first designated code block, the second designated code block may also include a logical link identifier LLID of the ONU and a sequence number SN of the last codeword in the original data stream.
  • the second designated code block may be the first code block of the last code word.
  • the second designated code block may also be an intermediate code block of the last codeword, or may be the last code block of the last codeword.
  • the embodiment of the present invention is not limited.
  • the second designated code block is different from the first specified code block, which is convenient for distinguishing the start and end of the data code stream.
  • the implementation of distinguishing the second designated code block from the first designated code block is described below.
  • the first designated code block and the second designated code block may include different reserved control words, for example, the first designated code block may include a reserved control word “/K/”, The second designated code block may include a reserved control word "/A/”.
  • the example is only one implementation manner of the embodiment of the present invention, and may be different in practical applications, and should not be construed as limiting.
  • the first designated code block and the second designated code block may include several pieces of identical information, such as a reserved control word “/K/”, a logical link identifier LLID of the ONU, and a codeword sequence. No. SN.
  • the combination order of the pieces of information in the first designated code block and the second designated code block is different, or the pieces of information are in the first designated code block and the second designated code block.
  • the number of bytes occupied by each is different.
  • the first designated code block is: /K//K//K//K/LLID&SN
  • the second designated code block is: LLID&SN/K//K///K//K/.
  • the example is only one implementation manner of the embodiment of the present invention, and may be different in practical applications, and should not be construed as limiting.
  • the second designated code block and the first specified code block may be two different predefined code blocks, for example, the first designated code block is “0X0011001100110011” ( Hexadecimal representation of 8 Bytes), the second designated code block is "0X1100110011001100” (8 bytes in hexadecimal notation).
  • the second designated code block and the first designated code block may also be other forms of predefined code blocks, which can be used to distinguish the beginning and the end of the data code stream.
  • the first designated code block may further carry the third indication information, where the third indication information may be used to indicate the number of FEC code words in the data code stream.
  • the ONU may extract the third indication information from the first designated code block. In this way, the ONU can determine, according to the third indication information, whether the FEC codeword in the data stream has been sent, and if the transmission is completed, turn off the laser.
  • an optical network unit ONU in a second aspect, is provided.
  • the optical network unit ONU can include: an optical module, a controller, a memory, and a bus system, and the controller and the memory are connected by the bus system.
  • the memory is used to store an implementation code of a method for transmitting an optical signal by the optical network unit described in the first aspect.
  • the controller is configured to execute program code stored in the memory, ie, a method of transmitting an optical signal by an optical network unit provided by any one of the first aspect or the possible implementation of the first aspect.
  • an optical network unit comprising a plurality of functional modules for respectively performing the method provided by any one of the first aspect or the possible embodiments of the first aspect.
  • the fourth aspect provides a passive optical network system, including: an optical line terminal, an optical distribution network, and an optical network unit, where: the optical network unit is configured to generate a data code stream corresponding to each channel according to the authorized time slot information, The first codeword in the data stream on each of the channels carries the first indication information; the optical network unit is further configured to: when the first indication information in the data stream is detected, A message is generated indicating that the optical module turns on the laser.
  • a fifth aspect a computer readable storage medium storing program code for implementing a method for transmitting an optical signal by an optical network unit described in the first aspect, the program code comprising the first aspect of operation The execution instruction of the method of transmitting the optical signal by the optical network unit.
  • FIG. 1 is a system architecture diagram of a PON system provided by an embodiment of the present application.
  • FIG. 2 is a schematic diagram of a multi-channel uplink transmission technology involved in the present application
  • FIG. 3 is a hardware architecture diagram of an ONU provided by an embodiment of the present application.
  • FIG. 4 is a functional block diagram of an ONU provided by an embodiment of the present application.
  • FIG. 5 is a schematic diagram showing a data structure of a codeword according to an embodiment of the present application.
  • FIG. 6 is a schematic diagram showing the data structure of another codeword provided by an embodiment of the present application.
  • FIG. 7 is a schematic flowchart diagram of a method for transmitting an optical signal by an optical network unit according to an embodiment of the present application
  • FIG. 8 is a schematic flowchart showing the implementation of the RS layer in the embodiment of FIG. 7 in an EPON scenario
  • FIG. 9 is a schematic flowchart showing the implementation of the embodiment of FIG. 7 in the PCS layer in an EPON scenario
  • FIG. 10 is a schematic flowchart diagram of a method for transmitting an optical signal by an optical network unit according to another embodiment of the present application.
  • FIG. 11 is a schematic diagram showing the structure of code blocks of two special code blocks defined in the embodiment of FIG. 10;
  • FIG. 12 is a schematic diagram showing the structure of a code block of another special code block defined in the embodiment of FIG. 10;
  • FIG. 13 is a schematic structural diagram of an ONU provided by an embodiment of the present application.
  • FIG. 3 is a schematic structural diagram of an optical network unit ONU according to an embodiment of the present invention.
  • the optical network unit ONU 300 may be an ONU in the EPON system shown in FIG. 1.
  • the ONU 300 may include a controller 301, a memory 302, an optical module 303, an Ethernet switching module 304, and an Ethernet interface 305. among them:
  • the optical module 303 is connected to the OLT through an optical fiber, and mainly implements data code stream transmission of the ONU uplink data and continuous reception of downlink data.
  • the optical module 303 can perform data distribution in units of code words through multiple channels, and can improve the uplink transmission bandwidth of the ONU.
  • the Ethernet switching module 304 is responsible for processing the exchange and forwarding of data packets, performing serial/parallel conversion of data, or parallel/serial conversion.
  • the Ethernet switching module 304 can support Layer 2 and Layer 3 switching, and can also support multiple switching rates such as 10 Mbps and 100 Mbps.
  • the Ethernet interface 305 is connected to the Ethernet switching module 304 to provide an Ethernet connection to the electronic device on the user side via the Ethernet.
  • Memory 302 is coupled to controller 301 for storing various software programs and/or sets of instructions.
  • memory 302 can include high speed random access memory, and can also include non-volatile memory, such as one or more magnetic disk storage devices, flash memory devices, or other non-volatile solid state storage devices.
  • the memory 302 can store an operating system (hereinafter referred to as a system) such as an embedded operating system such as LINUX.
  • a system such as an embedded operating system such as LINUX.
  • Memory 302 can be used to store implementations of one or more embodiments of the present application. Implementations of one or more embodiments of the present application may be specifically referenced to subsequent method embodiments.
  • the controller 301 can be a general central processing unit (CPU), a microcontroller, an application-specific integrated circuit (ASIC), or one or more programs for controlling the execution of the program of the present application. integrated circuit.
  • CPU central processing unit
  • ASIC application-specific integrated circuit
  • the controller 301 can implement the functions of the Harmonic Sublayer RS, the Physical Coding Sublayer PCS, the Physical Media Attachment (PMA) layer, and the Physical Media Dependent layer.
  • the harmonic sub-layer RS can be used to generate a data code stream corresponding to each channel according to the authorized time slot.
  • the harmonic sublayer RS and the physical coding sublayer PCS can communicate through the XGMII interface.
  • the physical coding sublayer PCS can be used to generate primitives that turn the laser on (or off). Then, the primitive passes through the PMA layer and the PMD layer, and finally reaches the optical module and triggers the optical module to transmit (or turn off) the optical signal.
  • the controller 301 can also implement more or less protocol layers, which are not limited herein.
  • controller 301 can be used to invoke and execute the implementation program of one or more embodiments of the present application stored in the memory 302. For details, refer to the subsequent embodiments, and details are not described herein.
  • FIG. 3 is only an implementation manner of the embodiment of the present invention.
  • the ONU 300 may further include more or fewer components, which are not limited herein.
  • an embodiment of the present invention provides a method for an optical network unit to transmit an optical signal, which can be used to enable ONU lasers in time, which is simple and effective.
  • the main principle of the embodiment of the present invention may include: the ONU generates a data code stream corresponding to each channel according to the authorized time slot in the harmonization sub-layer RS, where the first code word in the data stream corresponding to each channel is carried Identifying the indication information of the first codeword.
  • the ONU detects the indication information in the physical coding sublayer PCS, it determines that the codeword containing the indication information is the first codeword in the data code stream, and triggers the laser to be turned on, and sends the data code stream corresponding to Light signal. This will not only solve the problem of turning on the laser in time, but also change the existing EPON standard.
  • the indication information for identifying the first codeword may be referred to as first indication information.
  • the embodiment of the present invention provides the following two implementation manners.
  • the first indication information such as a newly defined XGMII control word, is carried by a check code placeholder of the first codeword. It should be noted that the example is only an implementation manner of the embodiment of the present invention. In an actual application, the first indication information may also be other information, such as a newly defined special code block, which is not limited herein.
  • Figure 5 exemplarily shows a check code placeholder in a codeword.
  • the check code may be an FEC check code.
  • the FEC check code placeholder can implement data rate matching at the RS layer and reserve a bearer location for the FEC check code generated by the PCS layer.
  • a special code block (distinguished from the code block format defined by the existing standard) is defined, and the first code word is identified by including the special code block in the first code word.
  • the special code block may be referred to as a first designated code block, and the first designated code block is the first indication information.
  • the last codeword in the data stream may further carry indication information for identifying the last codeword.
  • the indication information for identifying the last codeword may be referred to as second indication information.
  • the second indication information eg, a newly defined XGMII control word
  • the second indication information may be carried by a check code placeholder of the last codeword.
  • another special code block is defined, the last code word being identified by including the other special code block in the last code word.
  • the another special code block may be referred to as a second designated code block, and the second designated code block is the second indication information.
  • the PCS layer may determine the codeword carrying the second indication information as the last codeword in the data stream to trigger to turn off the laser.
  • the first codeword may further carry quantity information of a codeword included in the data code stream.
  • the PCS layer can also determine whether the codewords in the data stream are all transmitted according to the quantity information, and if the transmission is completed, trigger to turn off the laser.
  • the quantity information may be referred to as third indication information.
  • the special code block defined in the present application for indicating the start and end of the data code stream does not need to carry uplink data information or uplink control information, and only serves as a label, and does not need to be extended in the existing EPON standard.
  • the defined block format does not require changes to the existing block processing flow.
  • codewords involved in the present application may be FEC codewords, or may be other types of codewords.
  • a codeword includes a plurality of code blocks, for example, one FEC codeword includes 27 code blocks and an FEC check field.
  • the check code involved in the present application may be an FEC check code, for example, the last four 66-bit code blocks in the FEC code word, that is, the FEC check code, and the check code may also be other types of check codes. .
  • FIG. 7 is a schematic flowchart of a method for an optical network unit to transmit an optical signal according to an embodiment of the present application.
  • the indication information for controlling the laser to be turned on or off may be carried by the check code placeholder.
  • the embodiment of Fig. 7 will be described below.
  • the ONU may generate, according to the authorized time slot, a data code stream corresponding to each channel, where a check code placeholder of the first codeword in the data code stream transmitted on each channel may be used to carry the first indication information.
  • the first indication information may be a newly defined XGMII control word, or may be an XGMII control word reserved in an existing standard, or may be other types of indication information, such as a newly defined special code block, where No restrictions.
  • the ONU may generate a message indicating that the optical module turns on the laser.
  • a codeword for example, an FEC codeword
  • the codeword including the first indication information that is, the first codeword in the data stream
  • the message indicating that the optical module turns on the laser may be the primitive PMA_SIGNAL.request (true).
  • a check code placeholder of a last codeword in the data stream may be used to carry the second indication information.
  • the ONU can turn off the laser according to the second indication information.
  • the ONU may determine that the codeword that includes the second indication information, that is, the last codeword in the data stream, may trigger to turn off the laser.
  • the second indication information may be a newly defined XGMII control word, or may be an XGMII control word reserved in an existing standard, or may be other types of indication information, such as a new definition.
  • the special code block is not limited here. It can be understood that the first indication information is different from the second indication information, so as to facilitate distinguishing between the start and the end of the data stream.
  • the first indication information may also be carried in a payload of the first codeword.
  • the second indication information may also be carried in a payload of the last codeword.
  • EPON is taken as an example to describe the embodiment of FIG. 7 from the internal protocol layers of the ONU.
  • EPON usually uses FEC codewords for efficient data transmission.
  • the RS layer generates a data code stream corresponding to each channel according to the authorization time slot, and determines whether the FEC code word distributed to the channel i is the first FEC code word in the data code stream transmitted on the channel i.
  • Channel i can be any of a plurality of channels for transmitting the original data stream. Where i is the channel number and can take 0 or a positive integer.
  • the ONU can use four channels for data distribution, and the data transmission rate of each channel can be 25 Gbps.
  • These four channels can be numbered as: channel 0-3, i ⁇ 0,1,2,3 ⁇ .
  • the examples are merely illustrative of the embodiments of the invention and should not be construed as limiting.
  • the RS layer may use the FEC parity placeholder of the FEC codeword to carry the first indication information, for example, a newly defined XGMII control word, to indicate that the FEC codeword is the first one in the data stream.
  • FEC code words for example, a newly defined XGMII control word.
  • the first indication information may also be other information, such as a newly defined special code block, which is not limited herein.
  • the RS layer may determine whether the FEC codeword is the last one of the data streams transmitted on the channel i. Codeword. Specifically, if the FEC codeword is the last codeword in the data stream transmitted on the channel i, then S1014 is performed. Optionally, if the FEC codeword is not the last codeword in the data stream transmitted on the channel i, S1015 may be performed.
  • the RS layer may use the FEC parity placeholder of the FEC codeword to carry the second indication information, for example, a newly defined XGMII control word, to indicate that the FEC codeword is the last one in the data stream. FEC code word.
  • the RS layer may further use the FEC parity placeholder of the FEC codeword to carry a new indication information, where the new indication information is different from the first indication information and the second indication information.
  • the FEC codeword is an FEC codeword belonging to an intermediate position of the data stream, that is, the FEC codeword is neither the first FEC codeword in the data stream nor the last in the data stream. An FEC code word.
  • the internal processing of the PCS layer can be as shown in Figure 9:
  • the PCS layer receives an incoming multi-channel data stream of the RS layer through an XGMII interface (for example, a 25GXMIII or 10GXGMII interface), and detects whether the FEC codeword transmitted on each channel is in a data stream transmitted on the channel. The first or last FEC code word.
  • an XGMII interface for example, a 25GXMIII or 10GXGMII interface
  • the PCS layer may determine that the current FEC codeword is transmitted on the channel i.
  • the first FEC codeword match in the data stream produces a primitive PMA_SIGNAL.request(true) for triggering the laser to be turned on.
  • the primitive PMA_SIGNAL.request(true) approaches the PMA layer and the PMD layer to reach the optical module, and finally triggers the optical module to send the optical signal corresponding to the data stream.
  • the PCS layer may determine that the current FEC codeword is the data transmitted on the channel i.
  • the last FEC codeword in the codestream matches, producing a PMA_SIGNAL.request(false) that triggers the shutdown of the laser.
  • the primitive PMA_SIGNAL.request (false) approaches the PMA layer and the PMD layer to reach the optical module, and finally triggers the optical module to close the optical signal corresponding to the data stream.
  • the check code placeholder of the first codeword may also be used to carry the quantity information of the codewords included in the data code stream, that is, the third indication information.
  • the ONU can also determine whether the codewords in the data stream are all transmitted according to the quantity information, and if the transmission is completed, trigger the laser to be turned off.
  • the laser can be turned off by the primitive PMA_SIGNAL.request(false).
  • the third indication information may also be carried in a payload of the first codeword.
  • the ONU can trigger the shutdown of the laser when a certain number of Idle Blocks are detected.
  • the data detection module in the PCS layer may send a burst end delimiter (EOB), and then instruct the PMD sublayer to execute by the primitive PMA_SIGNAL.request (false). The procedure to turn off the laser.
  • EOB burst end delimiter
  • Embodiments of the method described in FIG. 7 are configured to carry first indication information for indicating the first codeword by using a check code placeholder of a first codeword in a data code stream corresponding to each channel.
  • the ONU is enabled to turn on the laser according to the first indication information, and send the data code stream in time.
  • the codeword does not need to carry the link identifier (Logical Link Identity, LLID) and the codeword sequence number SN of the ONU to distinguish the start and end of the data stream, and does not need to extend the existing EPON.
  • the code block format defined in the standard is simple and effective to implement.
  • FIG. 10 is a schematic flowchart diagram of a method for transmitting an optical signal by an optical network unit according to another embodiment of the present application.
  • a special code block (distinguished from the code block format defined by the existing EPON standard) is defined to represent the first indication information, and the special code block is included in the first code word to identify the The first codeword is used to trigger the laser to turn on.
  • the embodiment of Fig. 10 will be described below.
  • the ONU may generate a data code stream corresponding to each channel according to the authorization time slot, where the first codeword in the data code stream transmitted on each channel may include a first designated code for carrying the first indication information. Piece.
  • the first designated code block is a special code block newly defined by the embodiment of the present invention, and is used to carry the first indication information, and the first codeword is indicated. That is to say, the codeword containing the first designated code block is the first codeword in the data stream.
  • the first designated code block may be the first code block of the first codeword.
  • the first designated code block may also be an intermediate code block of the first codeword, or may be a last code block of the first codeword.
  • the embodiment of the present invention is not limited.
  • the first designated code block may include a link identifier LLID of the ONU and a sequence number SN of the first codeword in the original data stream.
  • the LLID can be used to identify the ONU, that is, which ONU is generated or sent by the identification data frame.
  • the first designated code block may be combined using IEEE 802.3 reserved control words (such as reserved control word "/K/"), LLID, and SN.
  • the first designated code block may be as shown in FIG. (A) or as shown in FIG. It should be noted that FIG. 11 only shows several implementation manners provided by the embodiments of the present invention.
  • the first designated code block may include a plurality of reserved control words.
  • the first designated code block may further include other information.
  • the ONU may generate a message indicating that the optical module turns on the laser.
  • the PCS layer may determine a codeword that includes the first designated code block, that is, a first code in the data code stream. The word can be used to generate a message indicating that the optical module turns on the laser.
  • the message indicating that the optical module turns on the laser may be the primitive PMA_SIGNAL.request (true).
  • the first designated code block may further carry the third indication information, where the third indication information may be used to indicate the number of FEC code words in the data code stream.
  • the ONU may extract the third indication information from the first designated code block. In this way, the ONU can determine, according to the third indication information, whether the FEC codeword in the data stream has been sent, and if the transmission is completed, turn off the laser.
  • the first designated code block is further extended to include the third indication information.
  • the IEEE 802.3 reserved control words such as the reserved control word "/K/"
  • the LLID the SN
  • Len the third indication information, indicating the number of codewords included in the data stream.
  • FIG. 12 only shows an implementation manner provided by the embodiment of the present invention. In actual applications, the combination order of the reserved control words, LLID, SN, and Len, and the number of bytes occupied by each are not affected. Figure 12 is limited.
  • the last codeword in the data stream transmitted on each channel may include a second designated code block for carrying the second indication information.
  • the ONU can turn off the laser according to the second designated code block.
  • the ONU may determine to include the second specified code block
  • the code word which is the last code word in the data stream, triggers the laser to turn off.
  • the second designated code block is a special code block newly defined in the embodiment of the present invention, and is used to represent the second indication information, indicating the last codeword. That is, the codeword containing the second designated code block is the last codeword in the data stream. Similar to the first designated code block, the second designated code block may also include a link identifier LLID of the ONU and a sequence number SN of the last codeword in the original data stream.
  • the second designated code block may be the first code block of the last code word.
  • the second designated code block may also be an intermediate code block of the last codeword, or may be the last code block of the last codeword.
  • the embodiment of the present invention is not limited.
  • the second designated code block is different from the first specified code block, which is convenient for distinguishing the start and end of the data code stream.
  • the implementation of distinguishing the second designated code block from the first designated code block is described below.
  • the first designated code block and the second designated code block may include different reserved control words.
  • the first designated code block may include a reserved control word as shown in FIG. 11 /K/
  • the second designated code block may include a reserved control word "/A/”.
  • the example is only one implementation manner of the embodiment of the present invention, and may be different in practical applications, and should not be construed as limiting.
  • the first designated code block and the second designated code block may include several pieces of identical information, such as a reserved control word "/K/", an LLID, and a codeword sequence number SN.
  • the combination order of the pieces of information in the first designated code block and the second designated code block is different, or the pieces of information are in the first designated code block and the second designated code block.
  • the number of bytes occupied by each is different.
  • the first designated code block is: /K//K//K//K/LLID&SN
  • the second designated code block is: LLID&SN/K//K///K//K/K/.
  • the example is only one implementation manner of the embodiment of the present invention, and may be different in practical applications, and should not be construed as limiting.
  • the second designated code block and the first specified code block may be two different predefined code blocks, for example, the first designated code block is “0X0011001100110011” ( The hexadecimal representation of 8 bytes), the second designated code block is "0X1100110011001100” (8 bytes in hexadecimal notation).
  • the second designated code block and the first designated code block may also be other forms of predefined code blocks, which can be used to distinguish the beginning and the end of the data code stream.
  • FIG. 10 embodiment is described in detail from the internal protocol layers of the ONU.
  • Step 1 When the data code stream corresponding to each channel is generated according to the authorization slot, the RS layer may insert the first designated code block in the first FEC codeword on each channel.
  • Step 2 The PCS layer receives the multi-channel data transmitted by the RS layer through the XGMII interface, and detects whether the first designated code block is included in the FEC codeword.
  • Step 3 If the first designated code block is included, the PCS layer may trigger the laser to be turned on by the primitive PMA_SIGNAL.request(true). Specifically, the primitive PMA_SIGNAL.request (false) approaches the PMA layer and the PMD layer to reach the optical module, and finally triggers the optical module to close the optical signal corresponding to the data stream.
  • the RS layer may further carry the third indication information in the first designated code block.
  • the PCS layer may extract the third indication information from the first designated code block, and may determine, according to the third indication information, whether the FEC codeword in the data code stream is sent, and if the sending is completed, The laser can be turned off by the primitive PMA_SIGNAL.request (false).
  • the RS layer may also insert the second designated code block in the last FEC codeword on each channel.
  • the PCS layer can determine that the FEC codeword containing the second designated code block is the last FEC codeword in the current data bitstream, through the primitive PMA_SIGNAL. Request (false) triggers turning off the laser, thereby turning off the optical signal corresponding to the data stream.
  • the PCS layer may also detect the number of consecutive idle code blocks (Idle Blocks) in the data stream, and if the consecutive idle code blocks reach a certain number (for example, 10 idle code blocks), it may determine that the data stream ends.
  • the laser is turned off by the primitive PMA_SIGNAL.request (false), thereby turning off the optical signal corresponding to the data stream.
  • the first designated code block being the first indication
  • the information can be used to enable the ONU to turn on the laser according to the first designated code block, so that the data stream can be sent in time.
  • the codeword does not need to carry the link identifier LLID of the ONU and the sequence number SN of the codeword to distinguish the start and end of the data stream, and does not need to extend the code defined in the existing EPON standard.
  • the block format is simple and effective to implement.
  • FIG. 13 is a schematic structural diagram of an optical network unit according to an embodiment of the present invention.
  • the optical network unit 500 shown in FIG. 13 may include a data distribution unit 501 and a laser control unit 502, where:
  • the data distribution unit 501 is configured to generate a data code stream corresponding to each channel according to the authorized time slot information, where the first code word in the data code stream on each channel carries the first indication information.
  • the laser control unit 502 is configured to generate a message indicating that the optical module turns on the laser when the first indication information in the data code stream is detected.
  • the first indication information may be used to indicate a first FEC codeword in the data code stream. Two implementations of the first indication information are described below.
  • the data distribution unit 501 can be configured to carry the first indication information, such as a newly defined XGMII control word, by a check code placeholder of the first codeword.
  • the first indication information may also be other information, such as a newly defined special code block, which is not limited herein.
  • the laser control unit 502 can determine the codeword, ie, the first codeword in the data stream, and turn on the laser.
  • the data distribution unit 501 can be configured to carry the newly defined XGMII control word by using the FEC parity placeholder of the first FEC codeword to indicate the first FEC codeword.
  • the laser control unit 502 can determine the FEC codeword, the first FEC codeword in the data stream, to turn on the laser.
  • the second implementation defines a special code block (distinguished from the code block format defined by the existing EPON standard): the first designated code block.
  • the data distribution unit 501 is configured to carry the first indication information by including a first designated code block in the first codeword.
  • the first designated code block is a special code block newly defined by the embodiment of the present invention, and is used to carry the first indication information, and the first codeword is indicated. That is to say, the codeword containing the first designated code block is the first codeword in the data stream.
  • the laser control unit 502 can determine the codeword, that is, the first codeword in the data stream, and turn on the laser, thereby transmitting the data stream corresponding to Light signal.
  • the data distribution unit 501 can be configured to define the first designated code block as: “/K//K//K//K/LLID&SN” (see (A) in FIG. 11).
  • the laser control unit 502 can turn on the laser.
  • the data distribution unit 501 may include an RS layer in the existing EPON standard
  • the laser control unit 502 may include a PCS layer in the existing EPON standard, and optionally may include a PMA sub- Layer and PMD sublayer.
  • the RS layer may carry the first indication information in the first FEC codeword in the data stream by using the FEC parity placeholder described in the foregoing or the implementation manner of the first specified code block.
  • the PCS layer receives the multi-channel data transmitted by the RS layer through the XGMII interface, and detects whether the FEC codeword transmitted on each channel includes the first indication information, and if so, determines that the FEC codeword is on the channel.
  • the first FEC codeword in the transmitted data stream is triggered to turn off the laser by the primitive PMA_SIGNAL.request(true).
  • data distribution unit 501 and the laser control unit 502 may also be modules defined in the future PON standard for implementing the respective respective functions described above.
  • the last codeword in the data stream may further carry indication information for identifying the last codeword, that is, the second Instructions. Two implementations of the second indication information are described below.
  • the data distribution unit 501 can be configured to carry the second indication information, such as a newly defined XGMII control word, by the check code placeholder of the last codeword at the RS layer.
  • the second indication information may also be other information, such as a newly defined special code block, which is not limited herein.
  • the laser control unit 502 can determine the codeword, that is, the last codeword in the data stream, and generate a message indicating that the optical module turns off the laser, thereby closing.
  • the data distribution unit 501 can be configured to carry the newly defined XGMII control word by using the FEC parity placeholder of the last FEC codeword to indicate the last FEC codeword.
  • the laser control unit 502 can determine the FEC codeword, ie, the last FEC codeword in the data stream, to turn off the laser.
  • the second implementation defines a special code block (distinguished from the code block format defined by the existing EPON standard): a second designated code block.
  • the data distribution unit 501 can be configured to carry the last codeword at the RS layer by including a second designated code block in the last codeword.
  • the second designated code block is a special code block newly defined by the embodiment of the present invention, and is used to carry the second indication information, and the second codeword is indicated. That is, the codeword containing the second designated code block is the last codeword in the data stream.
  • the laser control unit 502 can determine the codeword, that is, the last codeword in the data stream, and turn off the laser, thereby turning off the data stream. Corresponding optical signal.
  • the data distribution unit 501 can be configured to define the second designated code block as: “LLID&SN/K//K//K//K/”.
  • the laser control unit 502 can turn off the laser.
  • the data distribution unit 501 may include an existing EPON standard.
  • the quasi-RS layer, the laser control unit 502 may include a PCS layer in the existing EPON standard, and may optionally include a PMA sub-layer and a PMD sub-layer.
  • the RS layer may carry the second indication information in the last FEC codeword in the data stream by using the FEC parity placeholder described in the foregoing or the implementation manner of the second specified code block.
  • the PCS layer receives the multi-channel data transmitted by the RS layer through the XGMII interface, and detects whether the FEC codeword transmitted on each channel includes the second indication information. If included, the FEC codeword may be determined to be on the channel.
  • the last FEC codeword in the transmitted data stream is triggered to turn off the laser by the primitive PMA_SIGNAL.request(false).
  • data distribution unit 501 and the laser control unit 502 may also be modules defined in the future PON standard for implementing the respective respective functions described above.
  • the first codeword in the data stream may further carry the quantity information of the codeword included in the data stream, that is, the third indication information.
  • the laser control unit 502 can also determine whether the codewords in the data stream are all transmitted according to the quantity information, and if the transmission is completed, trigger the laser to be turned off, thereby turning off the optical signal corresponding to the data stream. Two implementations of the third indication information are described below.
  • the check code placeholder of the first codeword may also be used to carry the third indication information.
  • the laser control unit 502 can extract the third indication information from the check code placeholder of the first codeword in the PCS layer, and determine the code in the data code stream according to the third indication information. Whether the words are all sent, if the transmission is completed, trigger to turn off the laser.
  • the data distribution unit 501 is configured to carry the third indication information by using a FEC parity placeholder of the first FEC codeword, for example, Len (the length of the characterized data stream is Len, that is, the Len is included. FEC code word).
  • the laser control unit 502 can extract Len from the FEC parity placeholder of the first FEC codeword and monitor whether the FEC codeword in the data stream is transmitted. If the transmission is completed, the laser is turned off.
  • the first specified code block carries the third indication information.
  • the laser control unit 502 can extract the third indication information from the first designated code block, and determine, according to the third indication information, whether all the code words in the data code stream are completely transmitted, and if the sending is completed, Then trigger to turn off the laser.
  • the data distribution unit 501 can be configured to define the first designated code block as: “/K//K/LLID&SN&Len” (see FIG. 12).
  • the laser control unit 502 can extract Len from the first designated code block in the first FEC codeword, and monitor whether the FEC codeword in the data stream is transmitted, and if the transmission is completed, turn off the laser.
  • the data distribution unit 501 is further configured to carry the first indication information by using a payload of the first codeword.
  • the data distribution unit 501 is further configured to carry the second indication information by using a payload of a last codeword.
  • the data distribution unit 501 is further configured to carry the third indication information by using a payload of the first codeword.
  • the data distribution unit 501 may include an RS layer in the existing EPON standard
  • the laser control unit 502 may include a PCS layer in the existing EPON standard, and optionally may include a PMA sub- Layer and PMD sublayer.
  • the RS layer may carry the third indication information by using an FEC parity placeholder in the first FEC codeword or the first designated code block.
  • the PCS layer receives the multi-channel data transmitted by the RS layer through the XGMII interface, detects the first FEC codeword transmitted on each channel, and uses the FEC parity placeholder in the first FEC codeword or The first designated code block extracts the third indication information. Then, the PCS layer may determine, according to the third indication information, whether the FEC codeword in the data stream corresponding to each channel is sent. If the transmission is completed, the laser may be turned off by the primitive PMA_SIGNAL.request (false).
  • data distribution unit 501 and the laser control unit 502 may also be modules defined in the future PON standard for implementing the respective respective functions described above.
  • the laser control unit 502 can also be configured to detect the number of consecutive idle code blocks (Idle Blocks) in the data stream if the number of consecutive idle code blocks reaches a certain number (eg, 10 idle code blocks). Then, it can be determined that the data stream ends, and the laser is turned off by the primitive PMA_SIGNAL.request (false).
  • the present application further provides a passive optical network system, including: an optical line terminal, an optical distribution network, and an optical network unit, where: the optical network unit is configured to generate a data stream corresponding to each channel according to the authorized time slot information.
  • the first codeword in the data stream on each channel carries first indication information; the optical network unit is further configured to: when the first indication information in the data stream is detected , generating a message indicating that the optical module turns on the laser.
  • the passive optical network system may be the Ethernet passive optical network system 100 shown in FIG. 1.
  • the optical network unit may be the optical network unit 300 shown in FIG. 3 or FIG. 4, or may be the optical network unit 300 shown in FIG. It can be understood that the specific implementation of the optical network unit may refer to the embodiment of FIG. 7 or FIG. 10, and details are not described herein again.
  • Embodiments of the present invention by using a check code placeholder of a first codeword in a data code stream corresponding to each channel, carrying first indication information for indicating the first codeword, or
  • the first codeword includes a first designated code block for carrying the first indication information, and the ONU can enable the ONU to turn on the laser according to the first indication information, and send the data code stream in time.
  • the program can be stored in a computer readable storage medium, when the program is executed
  • the flow of the method embodiments as described above may be included.
  • the foregoing storage medium includes various media that can store program codes, such as a ROM or a random access memory RAM, a magnetic disk, or an optical disk.

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Abstract

本申请公开了一种光网络单元及光网络单元发送光信号的方法，所述方法可包括：根据授权时隙信息产生各个通道对应的数据码流，其中，所述各个通道上的数据码流中的第一个码字携带第一指示信息；当检测到所述数据码流中的所述第一指示信息时，生成指示光模块开启激光器的消息。上述方案可实现在数据码流发送上行数据时及时开启激光器，实现起来简单有效。

Description

一种光网络单元发送光信号的方法及光网络单元 技术领域
本申请涉及光通信领域，特别涉及一种光网络单元(Optical Network Unit，ONU)及光网络单元发送光信号的方法。
背景技术
无源光网络(Passive Optical Network，PON)是一种点对多点的网络拓扑结构，通常包括位于中心局(CentralOffice，CO)的光线路终端(Optical Line Terminal，OLT)、位于用户端的多个光网络单元(Optical Network Unit，ONU)以及位于两者之间的光分配网络(Optical Distribution Network，ODN)。
随着技术的不断发展，目前PON接入技术的标准主要包括EPON、10G-EPON标准等IEEE系列标准和GPON、XG-EPON、XGS-PON和TWDM-PON等国际通信联盟(International Telecommunication Union，ITU)系列标准。图1示出了现有EPON的网络结构，如图1所示，EPON100可以包括一个光线路终端(OLT)110、一个光分配网络120(ODN)和至少一个光网络单元(ONU)130，OLT110通过ODN120与至少一个ONU130通信。
在EPON100的系统中，从OLT到ONU称为下行方向。在下行传输时，OLT将送达各个ONU的下行业务组装成帧，采用广播方式发给多个ONU。即通过分光器分成N路独立的信号，各个ONU只提取发给自己的帧。下行传输支持连续工作模式。从ONU到OLT称为上行方向。各个ONU到OLT的上行数据通过时分多址(TDMA：Time Division Mutiple Access)方式共享信道进行传输，OLT为每一个ONU都分配一个上行传输时隙。
可以理解的，由于EPON系统是一个点(OLT)到多点(ONU)的网络结构。各个ONU不能同时向OLT发送上行数据，一个ONU只可以在分配给自己的授权时隙内通过激光器向OLT发送数据。因此，上行数据传输采用突发(Burst)工作模式。即，ONU根据上行授权时间向OLT突发发送上行数据。由上可以看出，在突发发送上行数据时，ONU激光器的开启是关键。
为了进一步扩展PON的应用，满足未来更大的带宽需求，业界提出了100G EPON，100G EPON是面向10G EPON后的下一代EPON系统。但是，目前EPON架构的物理层最高只能实现25Gbps的速率，要到达100Gbps的系统速率，需要将4个25Gbps的通道进行绑定以承载100Gbps的原始数据流。如图2所示，在100G EPON中，下行方向，OLT将一条原始数据流的数据报文分发至4个通道进行发送，而ONU则需要从4个通道接收上述数据报文，并将4个通道的数据报文进行重组形成一条原始数据流。上行方向，ONU将一条原始数据流的数据报文分发至4个通道进行发送，而OLT则需要从4个通道接收上述数据报文，并将4个通道的数据报文进行重组形成一条原始数据流。常用的数据传输方法为：调和子层(Reconciliation Sublayer，RS)以前向纠错(Forward Error Correction，FEC)码字为单位，将传输数据映射在不同通道上。但是，在将原始数据流以FEC码字为单位分发到不同的通道上进行传输时，由于ONU的调和子层(RS)需要进行速率匹配而在某一个(些)数据码流的首部可能会插入空闲码块。这样可能导致这个(些)数据码流中的第一个FEC码字中的数据不是以有效码块开始的，而是以空闲码块开始的。而按照现有10G  EPON的数据检测机制，物理编码子层(Physical coding sublayer，PCS)只有检测到有效数据码块才会触发开启激光器。如果在这个(些)数据码流中的第一个FEC码字中的数据是以空闲码块开始的，则会导致在这个(些)数据码流对应的通道上激光器不能按照授权时间及时开启。
发明内容
本发明实施例提供了一种光网络单元ONU及光网络单元发送光信号的方法，可实现ONU在发送上行数据码流时及时开启激光器，也不需要更改现有EPON标准中定义的码块格式及相关码块处理流程，实现起来简单有效。
第一方面，提供了一种光网络单元发送光信号的方法，所述方法可包括：ONU根据授权时隙信息产生各个通道对应的数据码流，其中，所述各个通道上的数据码流中的第一个码字携带第一指示信息。当检测到所述数据码流中的所述第一指示信息时，ONU生成指示光模块开启激光器的消息。
本申请中，所述第一指示信息可用于指示出所述数据码流中的第一个码字。
实施第一方面描述的方法，可实现ONU在发送数据码流时及时开启激光器，避免更改现有标准中定义的码块格式及相关码块处理流程，实现起来简单有效。
关于如何标识出数据码流中的第一个码字，本发明实施例提供了下述两种实现方式。
第一种实现方式，通过第一个码字的校验码占位符来承载所述第一指示信息，例如新定义的XGMII控制字。需要说明的，示例仅仅是本发明实施例的一种实现方式，实际应用中，所述第一指示信息还可以是其他信息，例如新定义的特殊码块，这里不作限制。
具体的，所述校验码可以是FEC校验码，例如EPON标准中的FEC码字中的最后4个66比特的FEC校验码，所述校验码也可以是其他类型的校验码。
第二种实现方式，定义特殊码块(区别于现有标准定义的码块格式)，通过在第一个码字中包含该特殊码块来承载所述第一指示信息。本发明实施例中，可以将该特殊码块称为第一指定码块。
可选的，所述第一指定码块可以是所述第一个码字的第一个码块(block)。可选的，所述第一指定码块也可以是所述第一码字的中间码块，还可以是所述第一码字的最后一个码块。关于所述第一指定码块在所述第一个码字中的位置，本发明实施例不作限制。
具体实现中，所述第一指定码块可包括ONU的链路标识(Logical Link Identity，LLID)和所述第一个码字在原始数据流中的序列号SN。其中，LLID可用于标识ONU，即标识数据帧是由哪个ONU生成的或发送的。例如，可以采用现有EPON标准中的预留控制字(如预留控制字“/K/”)、LLID和SN来组合成所述第一指定码块。需要说明的，本申请对所述预留控制字、LLID和SN的组合顺序以及各自所占的字节数量不作限制。所述第一指定码块可以包含多种预留控制字。所述第一指定码块还可以进一步的包含其他信息。
进一步的，数据码流中的最后一个码字还可以携带用于标识所述最后一个码字的第二指示信息。
类似的，在一种实现方式中，可以通过所述最后一个码字的校验码占位符来承载所述第二指示信息。这样，ONU可以根据所述第二指示信息关闭激光器。具体的，当检测到包 含所述第二指示信息时，ONU可以生成指示光模块关闭激光器的消息，从而触发关闭激光器。
与所述第一指示信息类似，所述第二指示信息可以是新定义的XGMII控制字，也可以是现有标准中预留的XGMII控制字，还可以是其他类型的指示信息，例如新定义的特殊码块，这里不作限制。可以理解的，所述第一指示信息与所述第二指示信息是不同的，便于区分数据码流的起始和结束。
可选的，所述第一指示信息也可以承载于所述第一个码字的净荷(payload)中，所述第二指示信息也可以承载于所述最后一个码字的净荷(payload)中。
在一些可选的实施例中，所述第一个码字的校验码占位符还可以用于承载数据码流所包含的码字的数量信息，即所述第三指示信息。这样，ONU也可以根据该数量信息判断数据码流中的码字是否全部发送完毕，如果发送完毕，则触发关闭激光器。以EPON为例，如果数据码流中的码字发送完毕，则可以通过原语PMA_SIGNAL.request(false)关闭激光器。可选的，所述第三指示信息也可以承载于所述第一个码字的净荷(payload)中。
类似的，在另一种实现方式中，单个通道上传输的数据码流中的最后一个码字可包括用于承载所述第二指示信息的第二指定码块。这样，ONU可以根据所述第二指定码块关闭激光器。具体的，当检测到承载所述第二指示信息的第二指定码块时，ONU可以生成指示光模块关闭激光器的消息，从而触发关闭激光器。
具体的，所述第二指定码块是本发明实施例新定义的特殊码块，用于表征所述第二指示信息，指示所述最后一码字。也即是说，包含所述第二指定码块的码字即数据码流中的最后一个码字。与所述第一指定码块类似，所述第二指定码块也可以包括ONU的逻辑链路标识LLID和所述最后一个码字在原始数据流中的序列号SN。
可选的，所述第二指定码块可以是所述最后一个码字的第一个码块(block)。可选的，所述第二指定码块也可以是所述最后一码字的中间码块，还可以是所述最后一码字的最后一个码块。关于所述第二指定码块在所述最后一个码字中的位置，本发明实施例不作限制。
可以理解的，所述第二指定码块与所述第一指定码块是不同的，便于区分数据码流的起始和结束。下面描述区分所述第二指定码块与所述第一指定码块的实现方式。
第一种实现方式，所述第一指定码块和所述第二指定码块可以包含不同的预留控制字，例如所述第一指定码块可以包括预留控制字“/K/”，所述第二指定码块可以包括预留控制字“/A/”。示例仅仅是本发明实施例的一种实现方式，实际应用中还可以不同，不应构成限定。
第二种实现方式，所述第一指定码块和所述第二指定码块可包含几种相同信息，例如预留控制字“/K/”、ONU的逻辑链路标识LLID和码字序列号SN。但是，这几种信息在所述第一指定码块和所述第二指定码块中的组合顺序不同，或者这几种信息在所述第一指定码块和所述第二指定码块中的各自占用的字节数量不同。例如，所述第一指定码块是：/K//K//K//K/LLID&SN，所述第二指定码块是:LLID&SN/K//K//K//K/。示例仅仅是本发明实施例的一种实现方式，实际应用中还可以不同，不应构成限定。
在其他一些可选的实现方式中，所述第二指定码块和所述第一指定码块可以是两种不同的预定义码块，例如，所述第一指定码块是“0X0011001100110011”(十六进制表示的8 个字节)，所述第二指定码块是“0X1100110011001100”(十六进制表示的8个字节)。所述第二指定码块和所述第一指定码块还可以是其他形式的预定义码块，能够用来区别数据码流的开始和结束即可。
在一些可选的实施例中，所述第一指定码块还可以携带所述第三指示信息，所述第三指示信息可用于指示所述数据码流中的FEC码字的数量。具体实现中，ONU在检测到所述第一指定码块后，可以从所述第一指定码块中提取出所述第三指示信息。这样，ONU便可以根据所述第三指示信息判断所述数据码流中的FEC码字是否已经发送完毕，如果发送完毕，则关闭激光器。
第二方面，提供了一种光网络单元ONU，所述光网络单元ONU可包括：光模块、控制器、存储器和总线系统，所述控制器和所述存储器通过该总线系统相连。其中：所述存储器用于存储第一方面描述的光网络单元发送光信号的方法的实现代码。所述控制器用于执行所述存储器中存储的程序代码，即执行第一方面或第一方面的可能的实施方式中的任意一种所提供的光网络单元发送光信号的方法。
第三方面，提供了一种光网络单元，包括多个功能模块，用于相应的执行第一方面或第一方面可能的实施方式中的任意一种所提供的方法。
第四方面，提供了一种无源光网络系统，包括:光线路终端、光分配网络和光网络单元，其中：所述光网络单元用于根据授权时隙信息产生各个通道对应的数据码流，其中，所述各个通道上的数据码流中的第一个码字携带第一指示信息；所述光网络单元还用于当检测到所述数据码流中的所述第一指示信息时，生成指示光模块开启激光器的消息。
第五方面，提供了一种计算机可读存储介质，所述可读存储介质上存储有实现第一方面描述的光网络单元发送光信号的方法的程序代码，该程序代码包含运行第一方面描述的光网络单元发送光信号的方法的执行指令。
附图说明
为了更清楚地说明本发明实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍。
图1示出了本申请一个实施例提供的PON系统的系统架构图；
图2示出了本申请涉及的一种多通道上行传输技术的示意图；
图3示出了本申请一个实施例提供的ONU的硬件架构图；
图4示出了本申请一个实施例提供的ONU的功能模块图；
图5示出了本申请一个实施例提供的一种码字的数据结构示意图；
图6示出了本申请一个实施例提供的另一种码字的数据结构示意图；
图7示出了本申请一个实施例提供的光网络单元发送光信号的方法的流程示意图；
图8示出了在EPON场景中RS层实施图7实施例的流程示意图；
图9示出了在EPON场景中PCS层实施图7实施例的流程示意图；
图10示出了本申请另一个实施例提供的光网络单元发送光信号的方法的流程示意图；
图11示出了图10实施例中定义的两种特殊码块的码块结构示意图；
图12示出了图10实施例中定义的再一种特殊码块的码块结构示意图；
图13示出了本申请一个实施例提供的ONU的结构示意图。
具体实施方式
本发明的实施方式部分使用的术语仅用于对本发明的具体实施例进行解释，而非旨在限定本发明。
参见图3，图3是本发明实施例提供的一种光网络单元ONU的结构示意图。光网络单元ONU300可以是图1所示EPON系统中的ONU。如图3所示，ONU300可包括：控制器301、存储器302、光模块303、以太网交换模块304和以太网接口305。其中：
光模块303通过光纤与OLT相连，主要实现ONU上行数据的数据码流发送和下行数据的连续接收。本发明实施例中，光模块303可以通过多通道以码字为单位进行数据分发，可提高ONU上行传输带宽。
以太网交换模块304负责处理数据包的交换转发，进行数据的串/并转换，或者并/串转换等。具体实现中，以太网交换模块304可支持二层、三层交换，也可以支持10Mbps、100Mbps等多种交换速率。
以太网接口305连接以太网交换模块304，通过以太网向用户侧的电子设备提供以太网连接。
存储器302与控制器301耦合，用于存储各种软件程序和/或多组指令。具体实现中，存储器302可包括高速随机存取的存储器，并且也可包括非易失性存储器，例如一个或多个磁盘存储设备、闪存设备或其他非易失性固态存储设备。存储器302可以存储操作系统(下述简称系统)，例如LINUX等嵌入式操作系统。存储器302可用于存储本申请的一个或多个实施例的实现程序。本申请的一个或多个实施例的实现具体可参考后续方法实施例。
控制器301可以是一个通用中央控制器(Central Processing Unit，CPU)，微控制器，特定应用集成电路(Application-Specific Integrated Circuit，ASIC)，或一个或多个用于控制本申请方案程序执行的集成电路。
如图4所示，控制器301可实现调和子层RS、物理编码子层PCS、物理媒质附加(Physical Media Attachment，PMA)层和物理媒质相关(Physical Media Dependent)层的功能。其中，调和子层RS可用于根据授权时隙产生各个通道对应的数据码流。调和子层RS和物理编码子层PCS之间可通过XGMII接口通信。物理编码子层PCS可用于生成打开(或关闭)激光器的原语。然后，所述原语途经PMA层和PMD层，最终到达光模块并触发光模块发送(或关闭)光信号。实际应用中，控制器301还可以实现更多或更少的协议层，这里不作限制。
本申请中，控制器301可用于调用和执行存储于存储器302中的本申请的一个或多个实施例的实现程序，具体请参见后续实施例，这里不赘述。
需要说明的，图3仅仅是本发明实施例的一种实现方式，实际应用中，ONU300还可以包括更多或更少的部件，这里不作限制。
基于图3所示的ONU 300，本发明实施例提供了一种光网络单元发送光信号的方法，可实现及时开启ONU激光器，简单有效。
本发明实施例涉及的主要原理可包括：ONU在调和子层RS根据授权时隙产生各个通道对应的数据码流，其中，每一个通道对应的数据码流中的第一个码字携带有用于标识所述第一个码字的指示信息。当ONU在物理编码子层PCS检测到该指示信息时，便确定包含该指示信息的码字是所述数据码流中的第一个码字，并触发开启激光器，发送所述数据码流对应的光信号。这样既可以实现及时开启激光器的问题，也不需要更改现有的EPON标准。在本发明实施例中，可以将用于标识第一个码字的指示信息称为第一指示信息。
关于如何标识出所述数据码流中的第一个码字，本发明实施例提供了下述两种实现方式。
第一种实现方式，通过第一个码字的校验码占位符来承载所述第一指示信息，例如新定义的XGMII控制字。需要说明的，示例仅仅是本发明实施例的一种实现方式，实际应用中，所述第一指示信息还可以是其他信息，例如新定义的特殊码块，这里不作限制。
图5示例性地示出了码字中的校验码占位符。在EPON标准中，校验码可以是FEC校验码。FEC校验码占位符可以在RS层实现数据速率匹配，并且为PCS层生成的FEC校验码预留承载位置。
第二种实现方式，定义特殊码块(区别于现有标准定义的码块格式)，通过在第一个码字中包含该特殊码块来标识出所述第一个码字。本发明实施例中，可以将该特殊码块称为第一指定码块，所述第一指定码块即所述第一指示信息。
进一步的，所述数据码流中的最后一个码字还可以携带用于标识所述最后一个码字的指示信息。本发明实施例中，可以将所述用于标识该最后一个码字的指示信息称为第二指示信息。类似的，在一种实现方式中，可以通过所述最后一个码字的校验码占位符来承载所述第二指示信息(例如新定义的XGMII控制字)。在另一种实现方式中，定义另一个特殊码块，通过在最后一个码字中包含所述另一个特殊码块来标识出所述最后一个码字。本发明实施例中，可以将所述另一个特殊码块称为第二指定码块，所述第二指定码块即所述第二指示信息。
具体实现中，PCS层可以将携带有所述第二指示信息的码字确定为所述数据码流中的最后一个码字，以触发关闭激光器。
可选的，所述第一个码字还可以携带所述数据码流所包含的码字的数量信息。这样，PCS层也可以根据该数量信息判断所述数据码流中的码字是否全部发送完毕，如果发送完毕，则触发关闭激光器。本发明实施例中，可以将该数量信息称为第三指示信息。
需要说明的，本申请中定义的用于指示所述数据码流起始和结束的特殊码块并不需要承载上行数据信息或上行控制信息，仅作标识作用，不需要扩展现有EPON标准中定义的码块格式，也不需要更改现有的码块处理流程。
需要说明的，本申请中涉及的所述码字可以是FEC码字，也可以是其他类型的码字。一个码字包括多个码块，例如一个FEC码字包括27个码块和FEC校验域。本申请中涉及的所述校验码可以是FEC校验码，例如FEC码字中最后4个66比特的码块即FEC校验码，所述校验码也可以是其他类型的校验码。
下面结合附图来详细说明本发明实施例提供的光网络单元发送光信号的方法。
图7是本申请的一个实施例提供的光网络单元发送光信号的方法的流程示意图。在图7实施例中，可以通过校验码占位符来承载用于控制激光器开启或关闭的指示信息。下面展开描述图7实施例。
S101，ONU可以根据授权时隙产生各个通道对应的数据码流，其中，各个通道上传输的数据码流中的第一个码字的校验码占位符可用于承载所述第一指示信息。
具体的，所述第一指示信息可以是新定义的XGMII控制字，也可以是现有标准中预留的XGMII控制字，还可以是其他类型的指示信息，例如新定义的特殊码块，这里不作限制。
S103当检测到所述数据码流中的所述第一指示信息时，ONU可以生成指示光模块开启激光器的消息。具体的，当检测到包含所述第一指示信息的码字(例如FEC码字)时，可以确定包含所述第一指示信息的码字即数据码流中的第一个码字，便可以触发开启激光器。具体在EPON场景中，指示光模块开启激光器的消息可以是原语PMA_SIGNAL.request(true)。
在一些可选的实施例中，所述数据码流中的最后一个码字的校验码占位符可用于承载所述第二指示信息。这样，ONU可以根据所述第二指示信息关闭激光器。具体的，当检测到包含所述第二指示信息的码字时，ONU可以确定包含所述第二指示信息的码字即所述数据码流中的最后一个码字，便可以触发关闭激光器。
与所述第一指示信息类似，所述第二指示信息可以是新定义的XGMII控制字，也可以是现有标准中预留的XGMII控制字，还可以是其他类型的指示信息，例如新定义的特殊码块，这里不作限制。可以理解的，所述第一指示信息与所述第二指示信息是不同的，便于区分数据码流的起始和结束。
可选的，如图6所示，所述第一指示信息也可以承载于所述第一个码字的净荷(payload)中。可选的，所述第二指示信息也可以承载于所述最后一个码字的净荷(payload)中。
下面以EPON为例，从ONU内部各协议层来描述图7实施例。EPON通常采用FEC码字进行有效数据的传输。
RS层的内部处理可如图8所示：
S1011，RS层根据授权时隙产生各个通道对应的数据码流，并判断分发至通道i的FEC码字是否是传输在通道i上的数据码流中的第一个FEC码字。通道i可以是用于传输原始数据流的多个通道中的任一个通道。其中，i是通道编号，可取0或正整数。
例如，在100G EPON的场景下，由于单个通道最大能够支持25Gbps的传输带宽，因此，ONU可采用4条通道进行数据分发，每一条通道的数据传输速率可为25Gbps。这四条通道可以编号为：通道0-3，i∈{0,1,2,3}。示例仅仅用于解释本发明实施例，不应构成限定。
具体的，如果分发至通道i的FEC码字是传输在通道i上的数据码流中的第一个FEC码字，则执行S1012；否则，执行S1013。
S1012，RS层可以利用所述FEC码字的FEC parity占位符承载所述第一指示信息，例如新定义的XGMII控制字，用以指示所述FEC码字是该数据码流中的第一个FEC码字。需要说明的，示例仅仅是本发明实施例的一种实现方式，实际应用中，所述第一指示信息还可以是其他信息，例如新定义的特殊码块，这里不作限制。
S1013，RS层可以判断所述FEC码字是否是传输在通道i上的数据码流中的最后一个 码字。具体的，如果所述FEC码字是传输在通道i上的数据码流中的最后一个码字，则执行S1014。可选的，如果所述FEC码字不是传输在通道i上的数据码流中的最后一个码字，则可以执行S1015。
S1014，RS层可以利用所述FEC码字的FEC parity占位符承载所述第二指示信息，例如新定义的XGMII控制字，用以指示所述FEC码字是该数据码流中的最后一个FEC码字。
S1015，可选的，RS层还可以利用所述FEC码字的FEC parity占位符承载一种新的指示信息，该新的指示信息区别于所述第一指示信息和所述第二指示信息，用于标识所述FEC码字是属于数据码流中间位置的FEC码字，即：所述FEC码字既不是数据码流中的第一个FEC码字，也不是数据码流中的最后一个FEC码字。
PCS层的内部处理可如图9所示：
S1021，PCS层通过XGMII接口(例如25GXMIII或10GXGMII接口)接收RS层传入的多通道数据码流，并检测每一个通道上传输的FEC码字是否是所述通道上传输的数据码流中的第一个或最后一个FEC码字。
S1022，在通道i上，如果从当前FEC码字的FEC parity占位符中提取出的信息与所述第一指示信息一致，则PCS层可以判定所述当前FEC码字与通道i上传输的数据码流中的第一个FEC码字匹配，产生用于触发开启激光器的原语PMA_SIGNAL.request(true)。具体的，原语PMA_SIGNAL.request(true)途径PMA层、PMD层到达光模块，最终触发光模块发送所述数据码流对应的光信号。
S1023，在通道i上，如果从当前FEC码字的FEC parity占位符中提取出的信息与所述第二信息一致，则PCS层可以判定所述当前FEC码字是通道i上传输的数据码流中的最后一个FEC码字匹配，产生用于触发关闭激光器的PMA_SIGNAL.request(false)。具体的，原语PMA_SIGNAL.request(false)途径PMA层、PMD层到达光模块，最终触发光模块关闭所述数据码流对应的光信号。
在一些可选的实施例中，所述第一个码字的校验码占位符还可以用于承载数据码流所包含的码字的数量信息，即所述第三指示信息。这样，ONU也可以根据该数量信息判断数据码流中的码字是否全部发送完毕，如果发送完毕，则触发关闭激光器。以EPON为例，如果数据码流中的码字发送完毕，则可以通过原语PMA_SIGNAL.request(false)关闭激光器。可选的，所述第三指示信息也可以承载于所述第一个码字的净荷(payload)中。
在一些可选的实施例中，当检测到一定数量的空闲码块(Idle Block)时，ONU可以触发关闭激光器。以EPON为例，当PCS层中的数据检测模块检测到一定数量的空闲码块时，可以发送突发结束定界符(EOB)，然后通过原语PMA_SIGNAL.request(false)指示PMD子层执行关闭激光器的程序。
实施图7描述的方法实施例，通过各个通道对应的数据码流中的第一个码字的校验码占位符来承载用于指示所述第一个码字的第一指示信息，可实现ONU根据所述第一指示信息开启激光器，及时发送数据码流。而且，在图7实施例中，码字不需要携带ONU的链路标识(Logical Link Identity，LLID)和码字序列号SN即可区分出数据码流的起始和结束，无需扩展现有EPON标准中定义的码块格式，实现起来简单有效。
图10是本申请的另一个实施例提供的光网络单元发送光信号的方法的流程示意图。在图10实施例中，定义特殊码块(区别于现有EPON标准定义的码块格式)来表征所述第一指示信息，通过在第一个码字中包含该特殊码块来标识出所述第一个码字，用于触发激光器开启。下面展开描述图10实施例。
S301，ONU可以根据授权时隙产生各个通道对应的数据码流，其中，各个通道上传输的数据码流中的第一个码字可包括用于承载所述第一指示信息的第一指定码块。
具体的，所述第一指定码块是本发明实施例新定义的特殊码块，用于承载所述第一指示信息，指示所述第一码字。也即是说，包含所述第一指定码块的码字即数据码流中的第一个码字。
可选的，所述第一指定码块可以是所述第一个码字的第一个码块(block)。可选的，所述第一指定码块也可以是所述第一码字的中间码块，还可以是所述第一码字的最后一个码块。关于所述第一指定码块在所述第一个码字中的位置，本发明实施例不作限制。
具体实现中，所述第一指定码块可包括ONU的链路标识LLID和所述第一个码字在原始数据流中的序列号SN。其中，LLID可用于标识ONU，即标识数据帧是由哪个ONU生成的或发送的。例如，如图11所示，可以采用IEEE 802.3的预留控制字(如预留控制字“/K/”)、LLID和SN来组合成所述第一指定码块。所述第一指定码块可以如图(A)所示，也可以如图(B)所示。需要说明的，图11仅仅示出了本发明实施例提供的几种实现方式，实际应用中，所述预留控制字、LLID和SN的组合顺序以及各自所占的字节数量不受图11限制。所述第一指定码块可以包含多种预留控制字。所述第一指定码块还可以进一步的包含其他信息。
S303，检测到所述数据码流中的所述第一指示信息时，ONU可以生成指示光模块开启激光器的消息。具体的，当检测到包含所述第一指定码块的码字(例如FEC码字)时，PCS层可以确定包含所述第一指定码块的码字即数据码流中的第一个码字，便可以生成指示光模块开启激光器的消息。具体在EPON场景中，指示光模块开启激光器的消息可以是原语PMA_SIGNAL.request(true)。
在一些可选的实施例中，所述第一指定码块还可以携带所述第三指示信息，所述第三指示信息可用于指示所述数据码流中的FEC码字的数量。具体实现中，ONU在检测到所述第一指定码块后，可以从所述第一指定码块中提取出所述第三指示信息。这样，ONU便可以根据所述第三指示信息判断所述数据码流中的FEC码字是否已经发送完毕，如果发送完毕，则关闭激光器。
进一步扩展所述第一指定码块，以包含所述第三指示信息。例如，如图12所示，可以采用IEEE 802.3的预留控制字(如预留控制字“/K/”)、LLID、SN和数据码流的长度Len来组合成所述第一指定码块。其中，Len即所述第三指示信息，表示数据码流包含的码字数量。需要说明的，图12仅仅示出了本发明实施例提供的一种实现方式，实际应用中，所述预留控制字、LLID、SN和Len的组合顺序以及各自所占的字节数量不受图12限制。
在一些可选的实施例中，各个通道上传输的数据码流中的最后一个码字可包括用于承载所述第二指示信息的第二指定码块。这样，ONU可以根据所述第二指定码块关闭激光器。具体的，当检测到包含所述第二指定码块的码字时，ONU可以确定包含所述第二指定码块 的码字即数据码流中的最后一个码字，便可以触发关闭激光器。
具体的，所述第二指定码块是本发明实施例新定义的特殊码块，用于表征所述第二指示信息，指示所述最后一码字。也即是说，包含所述第二指定码块的码字即数据码流中的最后一个码字。与所述第一指定码块类似，所述第二指定码块也可以包括ONU的链路标识LLID和所述最后一个码字在原始数据流中的序列号SN。
可选的，所述第二指定码块可以是所述最后一个码字的第一个码块(block)。可选的，所述第二指定码块也可以是所述最后一码字的中间码块，还可以是所述最后一码字的最后一个码块。关于所述第二指定码块在所述最后一个码字中的位置，本发明实施例不作限制。
可以理解的，所述第二指定码块与所述第一指定码块是不同的，便于区分数据码流的起始和结束。下面描述区分所述第二指定码块与所述第一指定码块的实现方式。
第一种实现方式，所述第一指定码块和所述第二指定码块可以包含不同的预留控制字，例如所述第一指定码块可以如图11所示包括预留控制字“/K/”，所述第二指定码块可以包括预留控制字“/A/”。示例仅仅是本发明实施例的一种实现方式，实际应用中还可以不同，不应构成限定。
第二种实现方式，所述第一指定码块和所述第二指定码块可包含几种相同信息，例如预留控制字“/K/”、LLID和码字序列号SN。但是，这几种信息在所述第一指定码块和所述第二指定码块中的组合顺序不同，或者这几种信息在所述第一指定码块和所述第二指定码块中的各自占用的字节数量不同。例如，所述第一指定码块是：/K//K//K//K/LLID&SN，所述第二指定码块是:LLID&SN/K//K//K//K/。示例仅仅是本发明实施例的一种实现方式，实际应用中还可以不同，不应构成限定。
在其他一些可选的实现方式中，所述第二指定码块和所述第一指定码块可以是两种不同的预定义码块，例如，所述第一指定码块是“0X0011001100110011”(十六进制表示的8个字节)，所述第二指定码块是“0X1100110011001100”(十六进制表示的8个字节)。所述第二指定码块和所述第一指定码块还可以是其他形式的预定义码块，能够用来区别数据码流的开始和结束即可。
以EPON为例，下面从ONU内部各协议层详细描述图10实施例。
步骤一，当根据授权时隙生成各个通道对应的数据码流时，RS层可以在每一个通道上的第一个FEC码字中插入所述第一指定码块。
步骤二，PCS层通过XGMII接口接收RS层传入的多通道数据，并检测FEC码字中是否包含所述第一指定码块。
步骤三，如果包含有所述第一指定码块，则PCS层可以通过原语PMA_SIGNAL.request(true)触发开启激光器。具体的，原语PMA_SIGNAL.request(false)途径PMA层、PMD层到达光模块，最终触发光模块关闭所述数据码流对应的光信号。
可选的，RS层还可以在所述第一指定码块中携带所述第三指示信息。这样，PCS层可以从所述第一指定码块中提取出所述第三指示信息，并可以根据所述第三指示信息判断数据码流中的FEC码字是否发送完毕，如果发送完毕，则可以通过原语PMA_SIGNAL.request(false)触发关闭激光器。
可选的，RS层还可以在每一个通道上的最后一个FEC码字中插入所述第二指定码块。 这样，一旦PCS层检测到所述第二指定码块，PCS层便可以确定包含所述第二指定码块的FEC码字是当前数据码流中的最后一个FEC码字，通过原语PMA_SIGNAL.request(false)触发关闭激光器，从而关闭该数据码流对应的光信号。
可选的，PCS层还可检测数据码流中的连续空闲码块(Idle Block)的数量，如果连续的空闲码块达到一定数量(例如10个空闲码块)，则可以判定数据码流结束，通过原语PMA_SIGNAL.request(false)触发关闭激光器，从而关闭该数据码流对应的光信号。
实施图10描述的方法实施例，通过在各个通道上传输的第一个码字中包含特殊码块来指示出所述第一个码字，所述第一指定码块即所述第一指示信息，可实现ONU根据所述第一指定码块开启激光器，可实现及时发送数据码流。而且，在图10实施例中，码字不需要携带ONU的链路标识LLID和码字的序列号SN即可区分出数据码流的起始和结束，无需扩展现有EPON标准中定义的码块格式，实现起来简单有效。
基于图1所示的网络架构，请参阅图13，图13是本发明实施例公开的一种光网络单元的结构示意图。如图13所示光网络单元500可以包括：数据分发单元501和激光器控制单元502，其中：
数据分发单元501，可用于根据授权时隙信息产生各个通道对应的数据码流，其中，所述各个通道上的数据码流中的第一个码字携带第一指示信息。
激光器控制单元502，可用于检测到所述数据码流中的所述第一指示信息时，生成指示光模块开启激光器的消息。
本发明实施例中，所述第一指示信息可用于指示出所述数据码流中的第一个FEC码字。下面描述所述第一指示信息的两种实现方式。
第一种实现方式，数据分发单元501可用于通过第一个码字的校验码占位符来承载所述第一指示信息，例如新定义的XGMII控制字。需要说明的，示例仅仅是本发明实施例的一种实现方式，实际应用中，所述第一指示信息还可以是其他信息，例如新定义的特殊码块，这里不作限制。
这样，一旦检测到包含所述第一指示信息的码字，激光器控制单元502便可确定该码字即数据码流中的第一个码字，开启激光器。
具体在EPON场景中，数据分发单元501可用于通过第一个FEC码字的FEC parity占位符来承载新定义的XGMII控制字，用来指示出所述第一个FEC码字。这样，一旦检测到包含所述新定义的XGMII控制字的FEC码字，激光器控制单元502便可确定该FEC码字即数据码流中的第一个FEC码字，开启激光器。
第二种实现方式，定义特殊码块(区别于现有EPON标准定义的码块格式)：第一指定码块。数据分发单元501可用于通过在第一个码字中包含第一指定码块来承载所述第一个指示信息。具体的，所述第一指定码块是本发明实施例新定义的特殊码块，用于承载所述第一指示信息，指示所述第一码字。也即是说，包含所述第一指定码块的码字即数据码流中的第一个码字。这样，一旦检测到包含所述第一指定码块的码字，激光器控制单元502便可确定该码字即数据码流中的第一个码字，开启激光器，从而发送所述数据码流对应的光信号。
具体在EPON场景中，数据分发单元501可用于定义所述第一指定码块为：“/K//K//K//K/LLID&SN”(见图11中的(A))。这样，一旦检测到所述第一指定码块，激光器控制单元502便可以开启激光器。
结合上述两种实现方式，在EPON场景中，数据分发单元501可以包括现有EPON标准中的RS层，激光器控制单元502可以包括现有EPON标准中的PCS层，可选的还可以包括PMA子层和PMD子层。
具体的，RS层可以通过上面内容描述的FEC parity占位符或者所述第一指定码块的实现方式，来在数据码流中的第一个FEC码字中携带所述第一指示信息。PCS层通过XGMII接口接收RS层传入的多通道数据，并检测每一个通道上传输的FEC码字是否包含所述第一指示信息，如果包含，则可以确定该FEC码字是所述通道上传输的数据码流中的第一个FEC码字，通过原语PMA_SIGNAL.request(true)触发关闭激光器。
需要说明的，数据分发单元501、激光器控制单元502还可以是未来PON标准中定义的用于实现上述各自相应功能的模块。
进一步的，为了便于激光器控制单元502控制激光器关闭，在一些可选的实施例中，数据码流中的最后一个码字还可以携带用于标识所述最后一个码字的指示信息，即第二指示信息。下面描述所述第二指示信息的两种实现方式。
第一种实现方式，数据分发单元501可用于在RS层通过最后一个码字的校验码占位符来承载所述第二指示信息，例如新定义的XGMII控制字。需要说明的，示例仅仅是本发明实施例的一种实现方式，实际应用中，所述第二指示信息还可以是其他信息，例如新定义的特殊码块，这里不作限制。
这样，一旦PCS层检测到包含所述第二指示信息的码字，激光器控制单元502便可确定该码字即数据码流中的最后一个码字，生成指示光模块关闭激光器的消息，从而关闭所述数据码流对应的光信号。
具体在EPON场景中，数据分发单元501可用于通过最后一个FEC码字的FEC parity占位符来承载新定义的XGMII控制字，用来指示出所述最后一个FEC码字。这样，一旦检测到包含所述第二指示信息的FEC码字，激光器控制单元502便可确定该FEC码字即数据码流中的最后一个FEC码字，关闭激光器。
第二种实现方式，定义特殊码块(区别于现有EPON标准定义的码块格式)：第二指定码块。数据分发单元501可用于在RS层通过在最后一个码字中包含第二指定码块来承载所述最后一个码字。具体的，所述第二指定码块是本发明实施例新定义的特殊码块，用于承载所述第二指示信息，指示所述第二码字。也即是说，包含所述第二指定码块的码字即数据码流中的最后一个码字。这样，一旦PCS层检测到包含所述第二指定码块的码字，激光器控制单元502便可确定该码字即数据码流中的最后一个码字，关闭激光器，从而关闭所述数据码流对应的光信号。
具体在EPON场景中，数据分发单元501可用于定义所述第二指定码块为：“LLID&SN/K//K//K//K/”。这样，一旦PCS层检测到所述第二指定码块，激光器控制单元502便可以关闭激光器。
结合上述两种实现方式，在EPON场景中，数据分发单元501可以包括现有EPON标 准中的RS层，激光器控制单元502可以包括现有EPON标准中的PCS层，可选的还可以包括PMA子层和PMD子层。
具体的，RS层可以通过上面内容描述的FEC parity占位符或者所述第二指定码块的实现方式，来在数据码流中的最后一个FEC码字中携带所述第二指示信息。PCS层通过XGMII接口接收RS层传入的多通道数据，并检测每一个通道上传输的FEC码字是否包含所述第二指示信息，如果包含，则可以确定该FEC码字是所述通道上传输的数据码流中的最后一个FEC码字，通过原语PMA_SIGNAL.request(false)触发关闭激光器。
需要说明的，数据分发单元501、激光器控制单元502还可以是未来PON标准中定义的用于实现上述各自相应功能的模块。
在一些可选的实施例中，数据码流中的第一个码字还可以携带数据码流所包含的码字的数量信息，即所述第三指示信息。这样，激光器控制单元502也可以根据该数量信息判断数据码流中的码字是否全部发送完毕，如果发送完毕，则触发关闭激光器，从而关闭所述数据码流对应的光信号。下面描述所述第三指示信息的两种实现方式。
第一种实现方式，所述第一个码字的校验码占位符还可以用于承载所述第三指示信息。这样，激光器控制单元502可以在PCS层从所述第一个码字的校验码占位符中提取出所述第三指示信息，并根据所述第三指示信息判断数据码流中的码字是否全部发送完毕，如果发送完毕，则触发关闭激光器。
具体在EPON场景中，数据分发单元501可用于通过第一个FEC码字的FEC parity占位符来承载所述第三指示信息，例如Len(表征数据码流的长度为Len，即包含Len个FEC码字)。这样，激光器控制单元502可以从第一个FEC码字的FEC parity占位符中提取出Len，并监控数据码流中的FEC码字是否发送完毕，如果发送完毕，则关闭激光器。
第二种实现方式，所述第一指定码块中携带有所述第三指示信息。这样，激光器控制单元502可以从所述第一指定码块中提取出所述第三指示信息，并根据所述第三指示信息判断数据码流中的码字是否全部发送完毕，如果发送完毕，则触发关闭激光器。
具体在EPON场景中，数据分发单元501可用于定义所述第一指定码块为：“/K//K/LLID&SN&Len”(见图12)。这样，激光器控制单元502可以从第一个FEC码字中的所述第一指定码块中提取出Len，并监控数据码流中的FEC码字是否发送完毕，如果发送完毕，则关闭激光器。
可选的，数据分发单元501还可用于通过第一个码字的净荷(payload)来承载所述第一指示信息。可选的，数据分发单元501还可用于通过最后一个码字的净荷(payload)来承载所述第二指示信息。可选的，数据分发单元501还可用于通过第一个码字的净荷(payload)来承载所述第三指示信息。
结合上述两种实现方式，在EPON场景中，数据分发单元501可以包括现有EPON标准中的RS层，激光器控制单元502可以包括现有EPON标准中的PCS层，可选的还可以包括PMA子层和PMD子层。
具体的，RS层可以通过第一个FEC码字中的FEC parity占位符或者所述第一指定码块来携带所述第三指示信息。PCS层通过XGMII接口接收RS层传入的多通道数据，检测出各个通道上传输的第一个FEC码字，并从所述第一个FEC码字中的FEC parity占位符或者 所述第一指定码块提取出所述第三指示信息。然后，PCS层可以根据所述第三指示信息判断各个通道各自对应的数据码流中的FEC码字是否发送完毕，如果发送完毕，则可以通过原语PMA_SIGNAL.request(false)触发关闭激光器。
需要说明的，数据分发单元501、激光器控制单元502还可以是未来PON标准中定义的用于实现上述各自相应功能的模块。
在一些可选的实施例中，激光器控制单元502还可用于检测数据码流中的连续空闲码块(Idle Block)的数量，如果连续的空闲码块达到一定数量(例如10个空闲码块)，则可以判定数据码流结束，通过原语PMA_SIGNAL.request(false)触发关闭激光器。
需要说明的，关于图13所示的ONU500包括的各个功能模块的具体实现，可参考前述方法实施例，这里不再赘述。
另外，本申请还提供了一种无源光网络系统，包括:光线路终端、光分配网络和光网络单元，其中：所述光网络单元可用于根据授权时隙信息产生各个通道对应的数据码流，其中，所述各个通道上的数据码流中的第一个码字携带第一指示信息；所述光网络单元还可用于当检测到所述数据码流中的所述第一指示信息时，生成指示光模块开启激光器的消息。
具体的，所述无源光网络系统可以是图1所示的以太网无源光网络系统100。其中，所述光网络单元可以是图3或图4所示的光网络单元300，也可以是图13所示的光网络单元300。可以理解的，所述光网络单元的具体实现可参考图7或图10实施例，这里不再赘述。
实施本发明实施例，通过各个通道对应的数据码流中的第一个码字的校验码占位符来承载用于指示所述第一个码字的第一指示信息，或者在所述第一个码字中包含用于承载所述第一指示信息的第一指定码块，可实现ONU根据所述第一指示信息开启激光器，及时发送所述数据码流。
本领域普通技术人员可以理解实现上述实施例方法中的全部或部分流程，该流程可以由计算机程序来指令相关的硬件完成，该程序可存储于计算机可读取存储介质中，该程序在执行时，可包括如上述各方法实施例的流程。而前述的存储介质包括：ROM或随机存储记忆体RAM、磁碟或者光盘等各种可存储程序代码的介质。

Claims (14)

  1. 一种光网络单元发送光信号的方法，其特征在于，包括：
    根据授权时隙信息产生各个通道对应的数据码流，其中，所述各个通道上的数据码流中的第一个码字携带第一指示信息；
    当检测到所述数据码流中的所述第一指示信息时，生成指示光模块开启激光器的消息。
  2. 如权利要求1所述的方法，其特征在于，所述第一个码字的校验码占位符用于承载所述第一指示信息。
  3. 如权利要求1或2所述的方法，其特征在于，所述各个通道上的数据码流中的最后一个码字用于携带第二指示信息；
    所述方法还包括：检测到所述第二指示信息时，生成指示光模块关闭激光器的消息。
  4. 如权利要求3所述的方法，其特征在于，所述最后一个码字的校验码占位符用于承载所述第二指示信息。
  5. 如权利要求1-4中任一项所述的方法，其特征在于，所述第一个码字还携带第三指示信息，所述第三指示信息用于指示所述数据码流中的码字数量；
    所述方法还包括：根据所述第三指示信息判断所述数据码流中的码字是否已经发送完毕，如果发送完毕，则生成指示光模块关闭激光器的消息。
  6. 如权利要求5所述的方法，其特征在于，所述第一个码字的校验码占位符还用于承载所述第三指示信息。
  7. 一种光网络单元，其特征在于，包括：数据分发单元和激光器控制单元，其中：
    所述数据分发单元，用于根据授权时隙信息产生各个通道对应的数据码流，其中，所述各个通道上的数据码流中的第一个码字携带第一指示信息；
    所述激光器控制单元，用于当检测到所述数据码流中的所述第一指示信息时，生成指示光模块开启激光器的消息。
  8. 如权利要求7所述的光网络单元，其特征在于，所述第一个码字的校验码占位符用于承载所述第一指示信息。
  9. 如权利要求7或8所述的光网络单元，其特征在于，所述各个通道上的数据码流中的最后一个码字用于携带第二指示信息；
    所述激光器控制单元，还用于检测到所述第二指示信息时，生成指示光模块关闭激光器的消息。
  10. 如权利要求9所述的光网络单元，其特征在于，所述最后一个码字的校验码占位符用于承载所述第二指示信息。
  11. 如权利要求7-10中任一项所述的光网络单元，其特征在于，所述第一个码字还携带第三指示信息，所述第三指示信息用于指示所述数据码流中的码字数量；
    所述激光器控制单元，还用于根据所述第三指示信息判断所述数据码流中的码字是否已经发送完毕，如果发送完毕，则生成指示光模块关闭激光器的消息。
  12. 如权利要求11所述的光网络单元，其特征在于，所述第一个码字的校验码占位符还用于承载所述第三指示信息。
  13. 一种光网络单元，包括控制器和光模块，其中：
    所述光模块用于接收和发送光信号；
    所述控制器用于根据授权时隙信息产生各个通道对应的数据码流，其中，所述各个通道上的数据码流中的第一个码字携带第一指示信息；
    所述控制器还用于当检测到所述数据码流中的所述第一指示信息时，生成指示光模块开启激光器的消息。
  14. 一种无源光网络系统，包括:光线路终端、光分配网络和光网络单元，其中：所述光网络单元用于根据授权时隙信息产生各个通道对应的数据码流，其中，所述各个通道上的数据码流中的第一个码字携带第一指示信息；所述光网络单元还用于当检测到所述数据码流中的所述第一指示信息时，生成指示光模块关闭激光器的消息。
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WO2005020481A1 (en) * 2003-08-18 2005-03-03 Teknovus, Inc. Method and apparatus for reducing data burst overhead in an ethernet passive optical network
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CN101610429A (zh) * 2008-06-19 2009-12-23 华为技术有限公司 提供无源光网络系统中上行突发数据的方法及装置
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WO2005020481A1 (en) * 2003-08-18 2005-03-03 Teknovus, Inc. Method and apparatus for reducing data burst overhead in an ethernet passive optical network
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