WO2014063349A1 - 无源光网络通信方法和系统、光线路终端 - Google Patents

无源光网络通信方法和系统、光线路终端 Download PDF

Info

Publication number
WO2014063349A1
WO2014063349A1 PCT/CN2012/083577 CN2012083577W WO2014063349A1 WO 2014063349 A1 WO2014063349 A1 WO 2014063349A1 CN 2012083577 W CN2012083577 W CN 2012083577W WO 2014063349 A1 WO2014063349 A1 WO 2014063349A1
Authority
WO
WIPO (PCT)
Prior art keywords
optical
downlink
optical network
network unit
frequency division
Prior art date
Application number
PCT/CN2012/083577
Other languages
English (en)
French (fr)
Inventor
彭桂开
周雷
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to CN201280001536.4A priority Critical patent/CN103109476B/zh
Priority to PCT/CN2012/083577 priority patent/WO2014063349A1/zh
Publication of WO2014063349A1 publication Critical patent/WO2014063349A1/zh

Links

Classifications

    • 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
    • H04B10/27—Arrangements for networking
    • H04B10/272—Star-type networks or tree-type networks
    • 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
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2587—Arrangements specific to fibre transmission using a single light source for multiple stations
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
    • H04J14/0241—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
    • H04J14/0242—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON
    • H04J14/0249—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for upstream transmission, e.g. ONU-to-OLT or ONU-to-ONU
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2697—Multicarrier modulation systems in combination with other modulation techniques
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
    • H04J14/0241—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
    • H04J14/0242—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON
    • H04J2014/0253—Allocation of downstream wavelengths for upstream transmission
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems

Definitions

  • the present invention relates to passive optical network technologies, and in particular, to a passive optical network communication method and system, and an optical line terminal. Background technique
  • PON Passive Optical Network
  • OFDM Orthogonal Frequency Division Multiplexing
  • OFDM Orthogonal Frequency Division Multiplexing Access Passive
  • OFDM technology can be used as a modulation technique to improve the spectrum utilization and channel capacity of the channel, effectively combating multipath and dispersion effects; on the other hand, it can be efficiently implemented by using subcarriers.
  • the OFDMA access enables flexible multi-user and multi-service bandwidth allocation. Different subcarriers can be assigned to different users or to different service classes. These features of OFDM technology make it particularly suitable for use in PON applications.
  • OFDMA-PON usually includes an optical line terminal located at the central office.
  • OLT Optical Network Unit
  • ONU Optical Network Unit
  • ODN optical distribution network
  • ODN ⁇ ⁇ is implemented by the splitter splitter Splitter.
  • data transmission between the OLT and the ONU uses an OFDM-based data modulation method.
  • high-speed serial data is first converted into low-speed parallel data, and then parallel data is mapped into a plurality of modulation vectors, and then inverse inverse Fourier Transform (IFFT) is performed; After adding a Cyclic Prefix (abbreviation: CP), and finally doing a parallel-to-serial conversion and digital-to-analog conversion (DAC), a continuous OFDM signal is generated and transmitted to the channel.
  • CP Cyclic Prefix
  • DAC digital-to-analog conversion
  • DAC digital-to-analog conversion
  • the uplink direction between the OLT and the ONU is multi-point to one-point data transmission.
  • an optical beat interference (OBI) is generated, especially when the center wavelengths of the light waves are the same or similar. Beat interference will produce DC or low frequency components, causing interference to subsequent data OFDM modulation. Therefore, each ONU must be operated at a different emission wavelength to eliminate or reduce the above OBI problem.
  • One way is to set a transmitter for transmitting the corresponding wavelength of the ONU in each ONU, and the cost is high; All ONUs use a transmitter, but the wavelength of the transmitter is tunable. For example, 32 transmit wavelengths can be tuned, but such tunable transmitters are expensive and not suitable for use in access networks; In this way, a laser is separately added to the OLT for transmitting an optical wave of an upstream wavelength, which is shared by each ONU for carrying respective uplink data, but in this manner, the ONU must be configured for uplink modulation.
  • the carrier-suppressed optical modulation method suppresses the original optical line, and needs to perform coherent reception at the OLT to recover the uplink data sent by the ONU.
  • the complicated technology is expensive. Summary of the invention
  • the present invention provides a passive optical network communication method and system, and an optical line terminal, which realizes that each ONU operates at a different transmission wavelength at a lower cost.
  • a first aspect of the present invention provides a passive optical network communication system, including: an optical line terminal, an optical distribution network, and at least one optical network unit, wherein the optical line terminal passes through the optical distribution network and the at least one optical network unit Make a connection;
  • the optical line terminal is configured to generate wide-spectrum light having a first wavelength and downlink light having a second wavelength, and the orthogonal frequency division to be transmitted to the at least one optical network unit by the downlink optical bearer Forming a downlink signal with the modulated downlink data, and transmitting the wide spectrum and downlink signals to the optical distribution network; and, for receiving an uplink signal sent by the at least one optical network unit, and for the uplink signal Obtaining uplink data corresponding to the at least one optical network unit by orthogonal frequency division multiplexing demodulation;
  • the optical distribution network is configured to divide the broad spectrum light received from the optical line terminal into at least one optical wave respectively corresponding to the at least one optical network unit, and send the at least one optical wave and the downlink signal to the Corresponding at least one optical network unit; and configured to: multiplex the uplink signal sent by the at least one optical network unit and send the uplink signal to the optical line terminal; the at least one optical network unit, configured to receive Determining downlink data corresponding to the optical network
  • the optical line terminal specifically includes: a wide spectrum light source and a first orthogonal frequency division multiplexing modulation module; and the wide spectrum light source is configured to generate the first The broad spectrum of light;
  • the first orthogonal frequency division multiplexing modulation module is configured to perform orthogonal frequency division multiplexing modulation on downlink data to be sent to the at least one optical network unit, and to receive at least one optical network unit
  • the transmitted uplink signal is subjected to orthogonal frequency division multiplexing demodulation, and the uplink data corresponding to the at least one optical network unit is obtained respectively.
  • the optical line terminal further includes: a first transmitting module and a first wavelength division multiplexer;
  • the first transmitting module is configured to carry downlink data that is orthogonally frequency division multiplexed and modulated by the first orthogonal frequency division multiplexing modulation module to be carried on the downlink light to form a downlink signal;
  • the first wavelength division multiplexer is configured to multiplex the downlink signal with the wide spectrum light and send the signal to the optical distribution network;
  • the optical distribution network further includes: a second wavelength division multiplexer
  • the second wavelength division multiplexer is configured to demultiplex the downlink signal and the wide spectrum light, so that the optical distribution network divides the demultiplexed wide spectrum light.
  • the optical distribution network specifically includes: an arrayed waveguide grating; the arrayed waveguide grating is configured to divide the wide-spectrum light sent by the optical line terminal into at least At least one optical wave corresponding to one optical network unit; and multiplexing the uplink signal sent by the at least one optical network unit.
  • the optical distribution network further includes: a beam splitter
  • the optical splitter is configured to divide the downlink signal demultiplexed by the second wavelength division multiplexer into at least one downlink signal respectively corresponding to the at least one optical network unit, and corresponding to the at least one downlink signal Broadcast to the at least one optical network unit.
  • the first orthogonal frequency division multiplexing modulation module includes multiple first orthogonal frequency division multiplexing modulation sending units, The number of the first transmitting modules is multiple; one of the first orthogonal frequency division multiplexing modulation transmitting unit and one first transmitting module constitutes one transmitting unit, and the number of the transmitting units is different from the multiple optical networks.
  • the number of units is equal;
  • the plurality of transmitting units are configured to send a plurality of downlink signals respectively carrying downlink data corresponding to the optical network unit, where the downlink signal has a second wavelength corresponding to the optical network unit.
  • a second aspect of the present invention provides an optical line terminal, including: a wide spectrum light source, a first orthogonal frequency division multiplexing modulation module, and a signal transmission module;
  • the broad spectrum light source for generating the broad spectrum light having a first wavelength
  • the first orthogonal frequency division multiplexing modulation module is configured to perform orthogonal frequency division multiplexing modulation on downlink data to be sent to the at least one optical network unit, and to receive from at least one optical network unit
  • the uplink signal is subjected to orthogonal frequency division multiplexing demodulation, and the uplink data corresponding to the at least one optical network unit is obtained respectively;
  • a signal transmitting module configured to generate downlink light having a second wavelength, and form a downlink signal by using the orthogonal frequency division multiplexing modulated downlink data to be sent to the at least one optical network unit by the downlink optical bearer;
  • the downlink signal is multiplexed with the wide spectrum light and then sent to the optical distribution network, so that the optical distribution network divides the wide spectrum light into at least one optical wave and respectively sends the signal to at least one optical network unit, and And causing the optical network unit to carry uplink data by using the optical wave.
  • the first orthogonal frequency division multiplexing modulation module includes a plurality of first orthogonal frequency division multiplexing modulation transmitting units, and the number of the first transmitting modules a plurality of; the first orthogonal frequency division multiplexing modulation transmitting unit and a first transmitting module form a transmitting unit, and the number of the transmitting units is equal to the number of the plurality of optical network units;
  • the plurality of transmitting units are configured to send a plurality of downlink signals respectively carrying downlink data corresponding to the optical network unit, where the downlink signal has a second wavelength corresponding to the optical network unit.
  • the first orthogonal frequency division multiplexing includes a first orthogonal frequency division multiplexing modulation transmitting unit, and a first transmitting module; a first orthogonal frequency division multiplexing modulation transmitting unit and a first transmitting module are connected to form a transmitting unit;
  • the transmitting unit is configured to perform downlink frequency division multiplexing modulation on the downlink data to be sent to the at least one optical network unit, and then carry the downlink signal with the second wavelength to form a downlink signal.
  • a third aspect of the present invention provides a passive optical network communication method, including:
  • Orthogonal frequency division multiplexing modulation is performed on the downlink data to be sent to the at least one optical network unit, and the modulated data is carried in the downlink light to form a downlink signal;
  • the optical distribution network divides the wide-spectrum light into at least one optical wave and respectively transmits the signal to at least one optical network unit, and causes the optical network unit to pass
  • the light wave carries uplink data
  • the generating the downlink light having the second wavelength includes: generating at least one downlink light, the at least one downlink light having the at least one optical network unit Corresponding wavelength;
  • Performing orthogonal frequency division multiplexing modulation on the downlink data to be sent to the at least one optical network unit, and carrying the modulated data in the downlink optical to form a downlink signal including: separately sending to the The downlink data of the at least one optical network unit is subjected to orthogonal frequency division multiplexing modulation, and the modulated data is respectively carried on at least one downlink light corresponding to the optical network unit, and formed with the at least one optical network.
  • a fourth aspect of the present invention provides a passive optical network communication method, including:
  • the downlink signal carries downlink data that is transmitted by the optical line terminal and modulated by orthogonal frequency division multiplexing, and the downlink data is carried by downlink light having a second wavelength
  • the light wave is obtained by splitting a broad spectrum light having a first wavelength generated by the optical line terminal
  • the technical effects of the passive optical network communication method and system and the optical line terminal provided by the present invention are as follows: only a wide-speaking light source needs to be set in the OLT, and is matched with the AWG in the ODN, and the wide-spectrum light source is generated by the AWG.
  • the wide-spectrum light is divided into a plurality of light waves to be injected into each ONU, which is equivalent to setting only one wide-speaking light source and one AWG.
  • FIG. 1 is a schematic structural diagram of an embodiment of a passive optical network communication system according to the present invention.
  • FIG. 2 is a schematic structural diagram of another embodiment of a passive optical network communication system according to the present invention.
  • FIG. 3 is a schematic structural diagram of still another embodiment of a passive optical network communication system according to the present invention.
  • FIG. 4 is a schematic structural view of an embodiment of an optical line terminal according to the present invention.
  • FIG. 5 is a schematic flowchart diagram of an embodiment of a method for communicating passive optical networks according to the present invention.
  • FIG. 6 is a schematic flow chart of another embodiment of a passive optical network communication method according to the present invention.
  • FIG. 7 is a schematic flowchart diagram of still another embodiment of a passive optical network communication method according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • the passive optical network communication system of this embodiment includes: OLT1, ODN12, and a plurality of ONUs 13, and the number of the ONUs 13 is
  • the method for realizing the different wavelengths of the ONUs is described in the embodiment, and at least two examples are taken as an example.
  • the OLT 11 is configured to generate wide-spectrum light having a first wavelength and downlink light having a second wavelength, and the orthogonal optical frequency division multiplexing modulation to be sent to the at least one optical network unit by the downlink optical bearer
  • the downlink data forms a downlink signal, and sends the wide spectrum light and the downlink signal to the optical distribution network; and, is configured to receive an uplink signal sent by the at least one optical network unit, and pass the uplink signal Performing frequency division multiplexing demodulation, respectively obtaining uplink data corresponding to the at least one optical network unit;
  • the OLT 11 may include: a first OFDM modulation module 111, and a broadband light source (BLS) 112 for generating broad spectrum light.
  • BSS broadband light source
  • the broad spectrum light source 112 can be, for example, a light emitting diode (LED) or a superluminescent light emitting diode (SLD); the wide spectrum light source 112
  • the wavelength may be referred to as a first wavelength; the first OFDM modulation module 111 may be configured to demodulate uplink signals of the received multiple ONUs to obtain uplink data corresponding to the multiple ONUs.
  • the first OFDM modulation module 111 performs OFDM mode demodulation or modulation on the data, which can improve spectrum utilization.
  • the ODN 12 is configured to divide the wide-spectrum light received from the optical line terminal into at least one optical wave respectively corresponding to the at least one optical network unit, and send the at least one optical wave and the downlink signal to the corresponding
  • the at least one optical network unit is configured to be multiplexed by the uplink signal sent by the at least one optical network unit and sent to the optical line terminal;
  • the ODN 12 may include: an Arrayed Waveguide Grating (abbreviated as AWG) 121, and the AWG 121 may be configured to divide the broad spectrum light received from the OLT into a plurality of light waves respectively corresponding to the plurality of ONUs.
  • the plurality of optical waves have mutually different wavelengths, and the plurality of optical waves are respectively sent to the plurality of ONUs.
  • the uplink signals sent by the plurality of ONUs are multiplexed and transmitted to the OLT.
  • the ONU 13 is configured to receive the downlink signal, perform orthogonal frequency division multiplexing demodulation on the downlink signal to obtain downlink data corresponding to the optical network unit, and send to be sent to the optical line.
  • the uplink data of the terminal multiplexed by frequency division multiplexing is carried on the optical wave received from the optical distribution network to form an uplink signal, and the uplink signal is sent to the optical distribution network; for example, the The ONU 13 may include: a second OFDM modulation module 131 and a transmitting module 132; the second OFDM modulation module 131 may be configured to perform OFDM modulation on the uplink data of the ONU, and the transmitting module 132 is configured to carry the OFDM modulated uplink data in the slave An uplink signal is formed on the optical wave received by the ODN, and the uplink signal is sent to the ODN.
  • the working principle of the passive optical network communication system of this embodiment is as follows: In order to realize that each ONU operates at different wavelengths, the present embodiment sets a wide-spectrum light source 112 in the OLT 11, and the wide-spectrum light generated by the wide-spectrum light source 112 Sending to the ODN, the wide-language light is divided into a plurality of optical waves having different wavelengths from the AWG 121 in the ODN, and the plurality of optical waves are transmitted to the plurality of ONUs; when the subsequent ONUs perform uplink transmission, the wavelength corresponding to the uplink signal is The wavelength of the light wave received by the ONU in advance, Therefore, the wavelengths of the uplink signals of the ONUs in the uplink transmission are also different from each other, and the OBI is not generated, thereby solving the problem of the optical beat interference.
  • the first OFDM modulation module 111 in the OLT can uplink signals to the received multiple ONUs. Demodulation is performed to obtain uplink data corresponding to the plurality of ONUs.
  • the passive optical network communication system of this embodiment only some modules included in the passive optical network communication system, such as an arrayed waveguide grating, a broad spectrum light source, etc., are shown in FIG. In a specific implementation, those skilled in the art can understand that various parts of the system, such as an OLT, an ODN, and an ONU, are not limited to including only the modules shown in FIG. 1.
  • the ODN may further include a splitter ( Splitter) and so on.
  • the passive optical network communication system described in this embodiment it is only necessary to set a wide-spectrum light source in the OLT, and cooperate with the AWG in the ODN, and divide the wide-spectrum light generated by the wide-speaking light source into multiple by the AWG.
  • a light wave can be injected into each ONU, which is equivalent to setting only one wide-speaking light source and one AWG.
  • the wide-spectrum light source and the AWG are low in cost, so the transmitter is set or used in each ONU than in the prior art.
  • the expensive tunable transmitters are low in cost, and the wavelengths of the ONUs are different by the combination of the above-mentioned wide-spectrum light source and the AWG, and the implementation method is simple, and the optical modulation method of the carrier suppression is used in comparison with the ONU in the prior art. And coherent reception at the OLT side is simple and easy to implement, so the cost is also low.
  • Embodiment 2 Two optional system structures are respectively described by Embodiment 2 and Embodiment 3: Embodiment 2
  • FIG. 2 is a schematic structural diagram of another embodiment of a passive optical network communication system according to the present invention. This embodiment further refines the structure of the passive optical network communication system based on the structure shown in FIG.
  • the OLT 11 of the system further includes: a transmitting module (Optical Transmitter, shown in FIG. 2 as an Optical Tx) 113 (which may be referred to as a first transmitting module), and a first receiving module (Optical Receiver, in Figure 2 is an illustration of Optical Rx) 114.
  • the transmitting module 113 may generate downlink light having a second wavelength, and carry the OFDM-modulated downlink data on the downlink optical to form a downlink signal, where the OFDM-modulated downlink data is an electrical signal, and is carried in the downlink.
  • the downlink signal formed on the light is an optical signal, so the transmitting module 113 is equivalent to performing photoelectric conversion, and converting the electrical signal into an optical signal can be transmitted on the trunk optical fiber.
  • the first receiving module 114 is configured to receive an uplink signal of the multiple ONUs, that is, the uplink signal of the ONU is to be received by the first receiving module 114 after entering the OLT, and the first receiving module 114 sends the uplink signal to the first
  • the OFDM modulation module 111 performs demodulation to obtain uplink data.
  • the first OFDM modulation module 111 in the OLT 11 may specifically include: a first OFDM modulation transmitting unit (OFDM Transmitter, OFDM Tx in FIG.
  • the OFDM modulation transmitting unit 115 is configured to perform OFDM modulation on the downlink data to be sent to the multiple ONUs, and send the OFDM-modulated downlink data to the transmitting module 113;
  • the modulation receiving unit 116 is configured to perform OFDM demodulation on the uplink signals of the ONUs received by the first receiving module 114, and obtain uplink data corresponding to each ONU.
  • the above method of OFDM modulation and OFDM demodulation uses a conventional OFDM-based data modulation method.
  • the first OFDM modulation transmitting unit converts the high-speed serial downlink data into low-speed parallel data first, and then the parallel data is mapped into multiple modulation vectors, and then performs fast Fourier.
  • Inverse transform after adding CP, and then performing parallel-to-serial conversion and digital-to-analog conversion, the downlink data after OFDM modulation can be obtained.
  • the subsequent transmitting module 113 carries the OFDM-modulated downlink data on the downlink optical to form a downlink signal, converts the electrical signal to the optical signal, and transmits the signal to the backbone optical fiber for transmission.
  • the OLT 11 receives the uplink signal sent by the ONU, after the first receiving module performs photoelectric conversion, the first OFDM modulation receiving unit performs analog-to-digital conversion and serial-to-parallel conversion on the uplink signal to generate a time sample sequence, and then removes the CP. Then perform fast Fourier transform, and perform appropriate digital signal processing on the transformed vector sequence, including channel equalization, forward error correction, etc., and then demodulate, map to generate parallel data, and finally restore to serial by parallel-to-serial conversion.
  • the data is the uplink data of the ONU.
  • the OLT 11 further includes: a first wavelength division multiplexer 117 and a circulator 118; wherein the first wavelength division multiplexer 117 is configured to multiplex the downlink signal with the wide spectrum light, the downlink signal and the width
  • the bands of the spectral light are different, for example, the downlink signal is the L band, and the wide spectrum light is the C band; the circulator 118 is configured to send the multiplexed downlink signal and the wide spectrum light to the ODN.
  • the circulator 118 is adapted to control the flow of signals, and the signal entering the circulator 118 can only travel in one direction, for example in the direction of the arrow shown in Figure 2; for example, from: the first wavelength division multiplexer 117
  • the downstream signal entering the circulator 118 can only be output from the port F of the trunk fiber in the direction of the arrow, and the downlink signal is transmitted on the trunk fiber 14; the uplink signal of the ONU received from the port F of the trunk fiber 14 can only be directed downward in the direction of the arrow. Transfer to the first receiving module 114.
  • the ODN 12 further includes: a second wavelength division multiplexer 122 and a beam splitter 123.
  • the second wavelength division multiplexer 122 is configured to demultiplex the downlink signal and the wide spectrum optical, that is, the downlink signal and the wide spectrum optical component.
  • the optical splitter 123 is configured to broadcast the downlink signal to the plurality of ONUs, specifically, the downlink signal demultiplexed by the second wavelength division multiplexer 122 is divided into at least one At least one downlink signal corresponding to the optical network unit, the divided plurality of downlink signals are actually signals carrying downlink data of the corresponding ONUs, and the at least one downlink signal is correspondingly broadcasted to at least one ONU, which is to be carried A downlink signal of downlink data of a certain ONU is correspondingly sent to the ONU.
  • the ODN 12 further includes: a wavelength division multiplexer 124 for multiplexing the optical waves processed by the AWG 121 and the optical splitter 123 and transmitting the optical waves to the ONU 13.
  • the ONU 13 further includes: a second receiving module (Optical Receiver) 133, which can receive the downlink signal broadcasted by the optical splitter 123, and send the downlink signal to the second OFDM modulation module 131 for OFDM demodulation.
  • the second OFDM modulation module 131 in the ONU 13 may specifically include: a second OFDM modulation transmitting unit (OFDM Transmitter) 134 and a second OFDM modulation receiving unit (OFDM Receiver) 135.
  • the second OFDM modulation sending unit 134 is configured to perform OFDM modulation on the uplink data of the ONU, and send the OFDM-modulated uplink data to the transmitting module 132 (which may be referred to as a second transmitting module); the second OFDM modulation receiving The unit 135 is configured to perform OFDM demodulation on the downlink signal received by the second receiving module 133 to obtain downlink data corresponding to the ONU.
  • the specific OFDM modulation and OFDM demodulation methods are the same as those of the OLT and will not be described again.
  • the transmitting module 132 in the ONU 13 may be a Reflective Modulator (R-Mod), and the Reflective Modulator is, for example, a Reflective Semiconductor Optical Amplifier (RSOA). Or a Reflective Electro-Absorption Modulator (REAM) or the like.
  • R-Mod Reflective Modulator
  • RSOA Reflective Semiconductor Optical Amplifier
  • RRM Reflective Electro-Absorption Modulator
  • the advantage of using the reflective modulator is that each ONU does not need to be defined as an upstream light wave that must emit a specific wavelength, and does not limit the emission wavelength of the ONU.
  • the transmitting module 132 can inject light waves corresponding to a certain wavelength in the above AWG.
  • the wavelength of the upstream optical wave is locked to the certain wavelength, that is, the transmitting module 132 locks the wavelength of the upstream optical wave to the colorless corresponding to the ONU according to the pre-injected optical wave, so that when the ONU is deployed, , is not limited by the wavelength correspondence, making the ONU deployment more flexible.
  • the ONU 13 of this embodiment may have multiple, for example, the first ONU, the second ONU, the ONU3, and the like.
  • the first ONU, the second ONU, the ONU3, and the like are shown in FIG. 2, only the structure of the first ONU, the second ONU, the ONU3, and the like are shown.
  • the structure of the ONU is the same as that of the first ONU, not shown.
  • the following is a description of the working principle of the passive optical network communication system in this embodiment from the downlink transmission and the uplink transmission in two directions, wherein the wavelengths of the uplink and downlink signals are different, and the wavelength of the downlink signal is set to ⁇ ⁇ , and Assuming that there are 32 ONUs, the wavelength of the broad-spectrum light emitted by the broad-spectrum light source is ⁇ u , and the wavelength of the upstream signal corresponding to the 32 ONUs divided by the AWG is set to ⁇ ul , into u2 , and into u32.
  • the OFDM Transmitter 15 in the OLT 11 performs OFDM modulation on the downlink data to be transmitted to each ONU, and the modulated downlink data is an electrical signal, which is transmitted to the Optical.
  • the Optical Transmitter 13 converts the electrical signal into an optical signal, specifically, the modulated downlink data is carried on the downlink light to form a downlink signal, and the wavelength of the downlink signal is
  • the downlink signal and the broad spectrum light emitted by the BLS 112 are multiplexed by the first wavelength division multiplexer 117 and then passed through the circulator 118 into the trunk fiber 14.
  • the main optical fiber 14 transmits a portion of the ODN 12, and the multiplexed downlink signal and the wide spectrum light are demultiplexed by the second wavelength division multiplexer 122, and the broad spectrum light is split by the AWG 121 into 32 separate optical waves having wavelengths of ⁇ . 1, ⁇ ⁇ 2, ... ..., ⁇ ⁇ 32, and then were injected into the reflective modulator 32, i.e.
  • ONU transmitter module 132 e.g., a wavelength of the light wave is ul injected into the first reflective modulator in ONU vessel, so that the lock of each ONU upstream signal wavelength were ul, ⁇ ⁇ 2, ising, ⁇ ⁇ 32, uplink signal of each ONU carried on respectively the 32 lightwave injection locking.
  • the downlink signal obtained by the demultiplexing of the second wavelength division multiplexer 122 enters the splitter 123, and is broadcasted by the optical splitter 123 to all the ONUs, specifically through the wavelength division multiplexer 124.
  • the broadcasts processed by the AWG 121 and the optical splitter 123 are multiplexed together and sent to the ONU.
  • the Optical Receiver 133 of the ONU After receiving the downlink signal, the Optical Receiver 133 of the ONU performs photoelectric conversion on the downlink signal, converts the optical signal into an electrical signal, and sends the electrical signal to the OFDM Receiver 35.
  • the OFDM Receiver 35 performs OFDM demodulation on the downlink signal to filter out the data of the subchannel corresponding to the ONU.
  • the downlink direction of the system is TDM+OFDM.
  • Uplink transmission The OFDM modulated uplink data is sent to a transmitting module (R-Mod) 132. Transmitting module 132
  • the uplink data is carried on the pre-injected optical wave to form an uplink signal, and the wavelength of the uplink signal is the wavelength of the injected optical wave.
  • the uplink signal sent by the transmitting module 132 of the first ONU is a light wave with a wavelength of ul .
  • the uplink 32 uplink signal optical waves sent by the ONUs are multiplexed by the AWG 121 in the ODN 12, and then enter the OLT 11 through the second wavelength division multiplexer 122 and the trunk optical fiber 14.
  • the Optical Receiver 14 (which is equivalent to a Photo Detector (abbreviated as PD)) is incident on the OLT through the circulator 118 in the OLT 11.
  • the Optical Receiver 14 has only one in the OLT, which receives uplink signals from all ONUs; since the 32 ONUs have wavelengths ⁇ ul , ⁇ u2 , ... and u32 are different, so in Optical Receiverl 14 There is no light difference interference 0BI on the top.
  • the Optical Receiver 14 photoelectrically converts the uplink signal to convert the optical signal into an electrical signal.
  • the uplink signal in the form of an electrical signal enters the OFDM Receiver 16 of the 0LT for demodulation, and recovers the data in the subchannel corresponding to each ONU, that is, the uplink direction is used.
  • the OFDM modulation or demodulation technique is as follows:
  • OFDM is a multi-carrier modulation technique.
  • the basic idea is to divide the channel into many orthogonal subchannels in the frequency domain, using one subcarrier for modulation on each subchannel, and subcarriers can use quadrature phase shift keying.
  • QPSK Quadrature Phase Shift Keying
  • QAM Quadrature Amplitude Modulation
  • This parallel transmission technology can transmit high-speed data streams.
  • OFDM differs from general multi-carrier transmission in that it allows sub-carrier spectrum partial overlap, and data signals can be separated from the aliased sub-carriers as long as the sub-carriers are orthogonal to each other. Since OFDM allows subcarrier spectral aliasing, its spectral efficiency is greatly improved, and thus it is an efficient modulation method.
  • FFT Digital Signal Processing
  • DSP Digital Signal Processing
  • the high-speed serial data is first converted into low-speed parallel data, and then the parallel data is mapped into a plurality of modulation vectors, and then multi-point fast Fourier transform is performed.
  • the CP is added, and finally, the parallel-serial conversion and the digital-to-analog conversion are performed to generate a continuous OFDM signal to be transmitted to the channel.
  • ADC Analog Digital Conversion
  • ADC analog-to-digital conversion
  • the string is transformed, the time sample sequence is generated, and the CP is removed to perform multi-point fast Fourier transform (FFT).
  • Appropriate digital signal processing is performed on the transformed vector sequence, including channel equalization, forward error correction, etc., and then demodulated, mapped to generate parallel data, and finally reduced to serial data by parallel-to-serial conversion.
  • the first OFDM modulation module of the embodiment includes a plurality of first OFDM modulation transmission units OFDM Tx, and the number of the first transmission module Optical Tx is also multiple; one OFDM Tx and one Optical Tx form one transmission unit,
  • the number of the transmitting units is equal to the number of the plurality of optical network units ONUs.
  • the plurality of the transmitting units of the embodiment are configured to send a plurality of downlink signals respectively carrying downlink data corresponding to the ONU, where the downlink signal has a second wavelength corresponding to the optical network unit.
  • each of the OFDM Tx and the Optical Tx has a plurality of OFDM Tx and Optical Tx, which are equal to the number of ONUs. For example, if there are 32 ONUs, the number of OFDM Tx and Optical Tx also has 32, respectively.
  • Each OFDM Optical Tx and the Tx corresponding transmitting unit, wherein the downlink data for a corresponding ONU performs OFDM modulation, and carried on to the downstream ONU light having a wavelength corresponding to, for example, in FIG. 3 dl, ⁇ ⁇ 2, etc., these dl , ⁇ ⁇ 2, etc. may all be referred to as the second wavelength.
  • the OLT of this embodiment further includes: an arrayed waveguide grating AWG for multiplexing a plurality of the downlink signals and transmitting the signals to the first wavelength division multiplexer 117.
  • the optical signals output by each Optical Tx have different wavelengths, for example, dl , X d 2 , ⁇ , X d 32 .
  • the optical signals output by the 32 Optical Tx correspond to different ONUs.
  • the multiplexed downlink signal is output, and the signal wavelength is d , and the wavelength is input (1 downlink signal and BLS wide spectrum light (the wavelength of the broad spectrum light is ⁇ u ) Together, they are multiplexed by the first wavelength division multiplexer 117 and then passed through the circulator 118 into the trunk fiber 14.
  • the ODN 12 of the embodiment may not include a splitter, and the downlink signal and the wide spectrum light of the above-mentioned trunk fiber 14 are divided by the AWG 121; specifically, the AWG121 divides the broad spectrum into 32 separations.
  • light waves which are a wavelength ⁇ ⁇ ⁇ ⁇ 2, ... ..., ⁇ ⁇ 32
  • the downlink signal is demultiplexed at a corresponding OLT 32 OFDM Tx and Optical Tx generated
  • the row signal, the demultiplexed downlink signals are injected into the transmitting module 132, which is a reflective modulator of 32 ONUs, together with the divided broad spectrum light.
  • a light wave having a wavelength of ⁇ 1 is injected into a reflective modulator of the first ONU such that the upstream signal wavelengths of the respective ONUs are locked as ⁇ ⁇ ⁇ ⁇ , ... , ⁇ ⁇ 32 , and the uplink of each ONU
  • the signals will be carried on the 32 injection-locked light waves, respectively.
  • each ONU carries the uplink data on the pre-injected optical wave to form an uplink signal, and the uplink 32 uplink signal optical waves that are sent are multiplexed by the AWG 121 in the ODN 12, and enter the OLT 11 through the trunk optical fiber 14.
  • the Optical Receiver 114 in the OLT is incident on the Optical Receiver 14 in the OLT 11.
  • the Optical Receiver 114 has only one uplink in the OLT, which receives the uplink signals from all the ONUs; since the wavelengths of the 32 ONUs are ul , ⁇ ⁇ , ... ... , ⁇ ⁇ 32 are different, so there is no light difference interference OBI on the Optical Receiverl 14.
  • Receiverl 14 photoelectrically converts the upstream signal and converts the optical signal into an electrical signal.
  • the uplink signal in the form of an electrical signal enters the OFDM Receiver 16 of the OLT for demodulation, and recovers the data in the subchannel corresponding to each ONU.
  • the optical line terminal OLT may include: a wide spectrum light source 41, a first orthogonal frequency division multiplexing modulation module 42 and a signal transmitting module 43; among them,
  • the broad spectrum light source 41 is configured to generate the broad spectrum light having a first wavelength
  • the first orthogonal frequency division multiplexing modulation module 42 is configured to perform orthogonal frequency division multiplexing modulation on downlink data to be sent to the at least one optical network unit; and, to be used from at least one optical network unit
  • the received uplink signal is subjected to orthogonal frequency division multiplexing (OFDM) demodulation, and the uplink data corresponding to the at least one optical network unit is obtained respectively;
  • OFDM orthogonal frequency division multiplexing
  • the signal transmitting module 43 is configured to generate downlink light having a second wavelength, and form a downlink signal by using the orthogonal frequency division multiplexing modulated downlink data to be sent to the at least one optical network unit by the downlink optical bearer; And multiplexing the downlink signal with the wide spectrum light, and transmitting the signal to the optical distribution network, so that the optical distribution network divides the wide spectrum light into at least one optical wave and sends the optical spectrum to at least one optical network unit, respectively. And causing the optical network unit to carry uplink data by using the optical wave.
  • the signal transmitting module 43 may include: a first transmitting module and a first wavelength division multiplexer; and a structure of the first transmitting module and the first wavelength division multiplexer may be referred to a system embodiment;
  • the first transmitting module is configured to generate downlink light having a second wavelength, and form, by using the downlink optical bearer, downlink data that is to be sent to the at least one optical network unit by orthogonal frequency division multiplexing modulation to form a downlink signal. ;
  • the first wavelength division multiplexer is configured to multiplex the downlink signal with the wide spectrum light, and then send the signal to the optical distribution network, so that the optical distribution network divides the wide spectrum light into And transmitting at least one optical wave to the at least one optical network unit, and causing the optical network unit to carry uplink data by using the optical wave.
  • the first orthogonal frequency division multiplexing modulation module includes a plurality of first orthogonal frequency division multiplexing modulation transmitting units, and the number of the first transmitting modules. a plurality of; the first orthogonal frequency division multiplexing modulation transmitting unit and a first transmitting module forming a transmitting unit, the number of the transmitting units being equal to the number of the plurality of optical network units; And a unit, configured to send multiple downlink signals respectively carrying downlink data corresponding to the optical network unit, where the downlink signal has a second wavelength corresponding to the optical network unit.
  • the first orthogonal frequency division multiplexing modulation module includes a first orthogonal frequency division multiplexing modulation transmitting unit, and a first transmitting module;
  • the first orthogonal frequency division multiplexing modulation transmitting unit and a first transmitting module are connected to form a transmitting unit;
  • the transmitting unit is configured to perform downlink frequency division multiplexing modulation on the downlink data to be sent to the at least one optical network unit, and then carry the downlink signal in the second wavelength to form a downlink signal.
  • the optical distribution network can generate the light wave corresponding to the ONU by dividing the wide-spectrum light, thereby injecting the light wave into the ONU as the uplink data of the ONU. It carries light waves, which can reduce the cost of the ONU.
  • FIG. 5 is a schematic flowchart of a method for communicating a passive optical network according to an embodiment of the present invention.
  • the method is performed by an OLT. This embodiment only describes the method briefly. For details, refer to the principle description in the system embodiment. As shown, the method can include:
  • Orthogonal frequency division multiplexing modulation is performed on downlink data to be sent to the at least one optical network unit, and the modulated data is carried in the downlink light to form a downlink signal.
  • the generating the downlink light having the second wavelength includes: generating at least one downlink light, the at least one downlink light respectively having a wavelength corresponding to the at least one optical network unit; and the sending to the at least The downlink data of an optical network unit is subjected to orthogonal frequency division multiplexing modulation, and the modulated data is carried in the downlink light to form a downlink signal, including:
  • Orthogonal frequency division multiplexing modulation is performed on the downlink data to be sent to the at least one optical network unit, and the modulated data is respectively carried on at least one downlink light corresponding to the optical network unit, forming and The plurality of downlink signals corresponding to the at least one optical network unit.
  • FIG. 6 is a schematic flowchart of another embodiment of a passive optical network communication method according to the present invention. The method is performed by an ONU. This embodiment only describes the method briefly. For details, refer to the principle description in the system embodiment. As shown in 6, the method can include:
  • the downlink signal carries downlink data that is transmitted by the optical line terminal and is subjected to orthogonal frequency division multiplexing modulation, where the downlink data is carried in downlink light having a second wavelength, and the optical wave is passed through the optical line terminal.
  • orthogonal frequency division multiplexing modulation where the downlink data is carried in downlink light having a second wavelength, and the optical wave is passed through the optical line terminal.
  • the uplink data to be sent to the optical line terminal is carried on the optical wave to form an uplink signal, and sent to the optical line terminal.
  • the ONU receives the optical wave obtained by the wide-spectrum light splitting generated by the optical line terminal as the optical wave carrying the uplink data, which is simpler to implement than the prior art, and reduces the cost of the ONU.
  • FIG. 7 is a schematic flowchart of still another embodiment of a passive optical network communication method according to the present invention.
  • This embodiment mainly describes a passive optical network communication method from a system perspective. As shown in Figure 7, it includes:
  • the wide-spectrum light source in the optical line terminal OLT generates wide-spectrum light having a first wavelength and downlink light having a second wavelength, where the OLT is to be sent to the at least one through the downlink optical bearer.
  • the downlink data of the orthogonal optical frequency division multiplexing modulated by the optical network unit forms a downlink signal, and sends the wide spectrum light and the downlink signal to the optical distribution network ODN;
  • the arrayed waveguide grating AWG in the ODN divides the wide-spectrum light into a plurality of optical waves respectively corresponding to the plurality of optical network units ONU, the wavelengths of the multiple optical waves are different from each other, and the multiple The light wave and the downlink signal are respectively sent to the plurality of ONUs;
  • the ONU performs orthogonal frequency division multiplexing demodulation on the received downlink signal to obtain downlink data corresponding to the optical network unit, and performs OFDM modulation on uplink data to be sent to the OLT, and performs OFDM modulation.
  • Uplink data is carried on the optical wave received from the ODN, forming an uplink signal, and sending the uplink signal to the ODN;
  • the ODN is multiplexed by the AWG to send uplink signals sent by the multiple ONUs to the OLT.
  • the OLT performs OFDM demodulation on the received uplink signals of the multiple ONUs to obtain uplink data corresponding to the multiple ONUs.
  • the aforementioned program can be stored in a computer readable storage medium.
  • the program when executed, performs the steps including the foregoing method embodiments; and the foregoing storage medium includes: a medium that can store program codes, such as a ROM, a RAM, a magnetic disk, or an optical disk.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Computing Systems (AREA)
  • Optical Communication System (AREA)

Abstract

本发明提供一种无源光网络通信方法和系统、光线路终端，其中系统包括OLT、ODN和ONU；OLT用于产生宽谱光及下行光，通过下行光承载待发送至至少一个光网络单元的经过正交频分复用调制的下行数据形成下行信号；ODN用于将宽谱光分割成分别与至少一个光网络单元对应的至少一个光波，并将至少一个光波和下行信号分别发送至对应的至少一个光网络单元；至少一个光网络单元用于接收下行信号，并对下行信号进行正交频分复用解调得到下行数据；并将待发送至光线路终端的经过正交频分复用调制的上行数据承载在从光分配网络接收的光波上形成上行信号，并将上行信号发送至光分配网络。本发明以较低的成本实现了每个ONU工作在不同的发射波长。

Description

无源光网络通信方法和系统、 光线路终端
技术领域
本发明涉及无源光网络技术， 尤其涉及一种无源光网络通信方法和系 统、 光线路终端。 背景技术
无源光网络（ Passive Optical Network , 简称： PON )由于建网成本较低， 作为一种经济有效的技术手段而在光接入网领域受到业界的瞩目。 当前， 在 光通信领域引入了正交频分复用 ( Orthogonal Frequency Division Multiplexing, 简称： OFDM )技术， 提出了基于 OFDM的正交频分多址复用 无源光网络 ( Orthogonal Frequency Division Multiplexing Access Passive Optical Network, 简称： OFDMA-PON ) 。 在光通信技术领域引入 OFDM技 术是一种差异化创新， OFDM技术一方面可以作为调制技术提高信道的频谱 利用率和信道容量， 有效对抗多径和色散效应； 另一方面可以利用子载波实 现高效的 OFDMA接入， 从而实现灵活的多用户和多业务的带宽分配。 不同 的子载波既可以分配给不同的用户， 也可以分配给不同的业务种类。 OFDM 技术的这些特性使其特别适合在 PON中应用。
在 OFDMA-PON 的架构中， 通常包括一个位于局端的光线路终端
( Optical Line Terminal,简称： OLT )和多个位于用户端的光网络单元（ Optical Network Unit, 简称： ONU ) , OLT与 ONU之间通过光分配网络 ( Optical Distribution Network, 简称： ODN )连接， 在无源光网络中， ODN ^ ^于分 光器分光器 Splitter实现的。
现有技术的 OFDMA-PON中， OLT和 ONU之间进行数据传输都釆用基 于 OFDM的数据调制方式。 例如， 在数据发送端， 高速串行数据先被变成低 速并行数据， 然后并行数据被映射成多个调制矢量， 再进行快速傅里叶逆变 换 (Inverse Fast Fourier Transform, 简称： IFFT); 变换后添加循环前缀 (Cyclic Prefix, 简称： CP), 最后作并串变换和数模转换 (Digital Analog Conversion, 简称： DAC), 产生连续的 OFDM信号向信道发送。 在接收端执行与上述相 反过程的处理获得最初的串行数据。其中，在 OLT和 ONU之间的上行方向， 是多点到一点的数据传输， 在 OLT 的接收端只有一个光电探测器 （Photo Detector, 简称： PD ) , 该 PD接收来自所有 ONU的上行信号光， 当 ONU 的两束或两束以上的光波入射到 OLT的 PD上时会产生光差拍干扰 (Optical Beat Interference, 简称： OBI), 特别是当所述光波的中心波长相同或者相近 时，光差拍干扰将产生直流或低频成分，造成对后续数据 OFDM调制的干扰。 因此， 必须让每个 ONU工作在不同的发射波长， 以消除或者降低上述的 OBI 问题。
目前主要有以下几种方式用于使得各 ONU 的工作波长不同： 一种方式 是，在每个 ONU中分别设置用于发射该 ONU对应波长的发射机，成本较高； 另一种方式是， 所有 ONU用一种发射机， 但是该发射机的波长是可调谐的， 例如， 可以调谐 32个发射波长， 但是这种可调谐发射机成本學贵， 不适合在 接入网中应用； 再一种方式是， 在 OLT单独增加一个激光器， 用于发送一个 上行波长的光波，该光波供各 ONU共享用于载送各自的上行数据，但是这种 方式中， ONU在作上行调制时都必须釆用载波抑制的光调制方式， 将原来的 光波谱线抑制掉， 并且在 OLT端需要进行相干接收， 以恢复出 ONU发送的 上行数据， 复杂技术， 成本也很昂贵。 发明内容
本发明提供一种无源光网络通信方法和系统、 光线路终端， 以较低的成 本实现每个 ONU工作在不同的发射波长。
本发明的第一方面是提供一种无源光网络通信系统， 包括： 光线路终端、 光分配网络和至少一个光网络单元， 所述光线路终端通过光分配网络与所述 至少一个光网络单元进行连接；
所述光线路终端， 用于产生具有第一波长的宽谱光、 以及具有第二波长 的下行光， 通过所述下行光承载待发送至所述至少一个光网络单元的经过正 交频分复用调制的下行数据形成下行信号， 并将所述宽谱光和下行信号发送 至所述光分配网络； 以及， 用于接收所述至少一个光网络单元发送的上行信 号， 并对所述上行信号通过正交频分复用解调， 分别得到所述至少一个光网 络单元对应的上行数据； 所述光分配网络， 用于将从所述光线路终端接收的宽谱光分割成分别与 至少一个光网络单元对应的至少一个光波， 并将所述至少一个光波和所述下 行信号分别发送至对应的所述至少一个光网络单元； 以及， 用于通过对所述 至少一个光网络单元发送的上行信号进行复用后发送至所述光线路终端； 所述至少一个光网络单元， 用于接收所述下行信号， 并对所述下行信号 进行正交频分复用解调得到与所述光网络单元对应的下行数据； 以及， 将待 发送至所述光线路终端的经过正交频分复用调制的上行数据承载在从所述光 分配网络接收的所述光波上， 形成上行信号， 并将所述上行信号发送至所述 光分配网络。
结合第一方面， 在第一种可能的实现方式中， 所述光线路终端具体包括: 宽谱光源和第一正交频分复用调制模块； 所述宽谱光源， 用于产生具有第一 波长的所述宽谱光；
所述第一正交频分复用调制模块， 用于将待发送至所述至少一个光网络 单元的下行数据进行正交频分复用调制； 以及， 用于对接收的至少一个光网 络单元发送的上行信号进行正交频分复用解调， 分别得到所述至少一个光网 络单元对应的上行数据。
结合第一方面的第一种可能的实现方式， 在第二种可能的实现方式中， 所述光线路终端还包括： 第一发射模块和第一波分复用器；
所述第一发射模块， 用于将所述第一正交频分复用调制模块进行正交频 分复用调制后的下行数据承载在所述下行光上形成下行信号；
所述第一波分复用器， 用于将所述下行信号与所述宽谱光进行复用后发 送至所述光分配网络；
所述光分配网络还包括： 第二波分复用器；
所述第二波分复用器， 用于将所述下行信号与所述宽谱光进行解复用， 以使得所述光分配网络对解复用后的所述宽谱光进行分割。
结合第一方面， 在第三种可能的实现方式中， 所述光分配网络具体包括: 阵列波导光栅； 所述阵列波导光栅， 用于将所述光线路终端发送的宽谱光分 割成与至少一个光网络单元对应的至少一个光波； 以及， 用于对所述至少一 个光网络单元发送的上行信号进行复用。
结合第一方面的第二种可能的实现方式， 在第四种可能的实现方式中， 所述光分配网络还包括： 分光器；
所述分光器， 用于将所述第二波分复用器解复用后的下行信号， 分割成 分别与至少一个光网络单元对应的至少一个下行信号， 并将所述至少一个下 行信号对应广播至所述至少一个光网络单元。
结合第一方面的第二种可能的实现方式， 在第五种可能的实现方式中， 所述第一正交频分复用调制模块包括多个第一正交频分复用调制发送单元， 所述第一发射模块的数量为多个； 一个所述第一正交频分复用调制发送单元 和一个第一发射模块组成一个发射单元， 所述发射单元的数量与所述多个光 网络单元的数量相等；
多个所述发射单元， 用于发送分别承载有与所述光网络单元对应的下行 数据的多个下行信号，所述下行信号具有与所述光网络单元对应的第二波长。
本发明的第二方面提供一种光线路终端， 包括： 宽谱光源、 第一正交频 分复用调制模块和信号发射模块；
所述宽谱光源， 用于产生具有第一波长的所述宽谱光；
所述第一正交频分复用调制模块， 用于将待发送至所述至少一个光网络 单元的下行数据进行正交频分复用调制； 以及， 用于将从至少一个光网络单 元接收的上行信号进行正交频分复用解调， 分别得到所述至少一个光网络单 元对应的上行数据；
信号发射模块， 用于产生具有第二波长的下行光， 并通过所述下行光承 载待发送至所述至少一个光网络单元的经过正交频分复用调制的下行数据形 成下行信号； 并将所述下行信号与所述宽谱光进行复用后发送至所述光分配 网络， 以使得所述光分配网络将所述宽谱光分割成至少一个光波分别发送至 至少一个光网络单元， 并使得所述光网络单元通过所述光波承载上行数据。
结合第二方面， 在第一种可能的实现方式中， 所述第一正交频分复用调 制模块包括多个第一正交频分复用调制发送单元， 所述第一发射模块的数量 为多个； 一个所述第一正交频分复用调制发送单元和一个第一发射模块组成 一个发射单元， 所述发射单元的数量与多个光网络单元的数量相等；
多个所述发射单元， 用于发送分别承载有与所述光网络单元对应的下行 数据的多个下行信号，所述下行信号具有与所述光网络单元对应的第二波长。
结合第二方面， 在第二种可能的实现方式中， 所述第一正交频分复用调 制模块包括一个第一正交频分复用调制发送单元， 以及一个第一发射模块； 一个所述第一正交频分复用调制发送单元和一个第一发射模块连接组成一个 发射单元； 所述发射单元， 用于将待发送至所述至少一个光网络单元的下行 数据进行正交频分复用调制后， 均承载在所述具有第二波长的下行光形成下 行信号。
本发明的第三方面提供一种无源光网络通信方法， 包括：
产生具有第一波长的宽谱光、 以及具有第二波长的下行光；
对待发送至所述至少一个光网络单元的下行数据进行正交频分复用调 制， 并将调制后的所述数据承载在所述下行光形成下行信号；
将所述宽谱光和下行信号发送至光分配网络， 以使得所述光分配网络将 所述宽谱光分割成至少一个光波分别发送至至少一个光网络单元， 并使得所 述光网络单元通过所述光波承载上行数据；
接收所述至少一个光网络单元发送的上行信号， 并对所述上行信号通过 正交频分复用解调， 分别得到所述至少一个光网络单元对应的上行数据。
结合第三方面， 在第一种可能的实现方式中， 所述产生具有第二波长的 下行光， 包括： 产生至少一个下行光， 所述至少一个下行光分别具有与所述 至少一个光网络单元对应的波长；
所述对待发送至所述至少一个光网络单元的下行数据进行正交频分复用 调制， 并将调制后的所述数据承载在所述下行光形成下行信号， 包括： 分别对待发送至所述至少一个光网络单元的下行数据进行正交频分复用 调制， 并将调制后的所述数据分别承载在与所述光网络单元对应的至少一个 下行光上， 形成与所述至少一个光网络单元对应的多个下行信号。
本发明的第四方面是提供一种无源光网络通信方法， 包括：
接收光线路终端发送的下行信号和光波， 所述下行信号承载有所述光线 路终端发送的经过正交频分复用调制的下行数据， 所述下行数据承载在具有 第二波长的下行光， 所述光波是通过对所述光线路终端产生的具有第一波长 的宽谱光分割得到；
对所述下行信号进行正交频分复用解调， 得到所述下行数据； 并将待发 送至所述光线路终端的上行数据承载在所述光波上， 形成上行信号， 发送至 所述光线路终端。 本发明提供的无源光网络通信方法和系统、 光线路终端的技术效果是： 只需要在 OLT中设置一个宽语光源， 并与 ODN中的 AWG相配合， 由 AWG 将该宽谱光源产生的宽谱光分割成多个光波注入各 ONU即可，相当于只设置 一个宽语光源和一个 AWG, 该宽语光源和 AWG的成本低， 所以比现有技术 中的在每个 ONU中都设置发射机、 或者釆用昂贵的可调谐发射机都成本低， 并且， 釆用上述宽谱光源和 AWG的组合方式实现各 ONU的波长不同， 实现 方法艮简单， 比现有技术中的 ONU釆用载波抑制的光调制方式以及 OLT端 进行相干接收， 要简单易行， 更容易实施， 所以成本也较低。 附图说明 图 1为本发明无源光网络通信系统一实施例的结构示意图；
图 2为本发明无源光网络通信系统另一实施例的结构示意图；
图 3为本发明无源光网络通信系统又一实施例的结构示意图；
图 4为本发明光线路终端实施例的结构示意图；
图 5为本发明无源光网络通信方法一实施例的流程示意图；
图 6为本发明无源光网络通信方法另一实施例的流程示意图；
图 7为本发明无源光网络通信方法又一实施例的流程示意图。 具体实施方式 实施例一
图 1为本发明无源光网络通信系统一实施例的结构示意图，如图 1所示, 本实施例的无源光网络通信系统包括： OLTl l、 ODN12和多个 ONU13 , 该 ONU13的数量在具体实施中也可以为一个， 只是本实施例为了说明各 ONU 的波长不同的实现方法， 以至少两个为例进行说明。
其中， OLT11 , 用于产生具有第一波长的宽谱光、 以及具有第二波长的 下行光， 通过所述下行光承载待发送至所述至少一个光网络单元的经过正交 频分复用调制的下行数据形成下行信号， 并将所述宽谱光和下行信号发送至 所述光分配网络； 以及， 用于接收所述至少一个光网络单元发送的上行信号, 并对所述上行信号通过正交频分复用解调， 分别得到所述至少一个光网络单 元对应的上行数据； 例如， OLT11中可以包括： 第一 OFDM调制模块 111、 以及用于产生宽 谱光的宽谱光源 （broadband light source, 简称： BLS ) 112。 该宽谱光源 112 例如可以是， 发光二级管（Light Emitting Diode, 简称： LED ) 、 超辐射发光 二级管 （ Superluminescent Light Emitting Diodes , 简称： SLD )等多种器件； 该宽谱光源 112的波长可以称为第一波长； 第一 OFDM调制模块 111可以用 于对接收的多个 ONU的上行信号进行解调， 分别得到该多个 ONU对应的上 行数据。 本实施例釆用第一 OFDM调制模块 111对数据进行 OFDM方式的 解调或者调制， 可以提高频谱利用率。
所述的 ODN12,用于将从所述光线路终端接收的宽谱光分割成分别与至 少一个光网络单元对应的至少一个光波， 并将所述至少一个光波和所述下行 信号分别发送至对应的所述至少一个光网络单元； 以及， 用于通过对所述至 少一个光网络单元发送的上行信号进行复用后发送至所述光线路终端；
例如， 所述的 ODN12中可以包括： 阵列波导光栅（ Arrayed Waveguide Grating, 简称： AWG ) 121 , 该 AWG121可以用于将从 OLT接收的宽谱光 分割成分别与多个 ONU对应的多个光波，所述多个光波的波长互不相同，并 将所述多个光波分别发送至所述多个 ONU; 还可以用于对多个 ONU发送的 上行信号复用后发送至 OLT。
所述的 ONU13 , 用于接收所述下行信号， 并对所述下行信号进行正交频 分复用解调得到与所述光网络单元对应的下行数据； 以及， 将待发送至所述 光线路终端的经过正交频分复用调制的上行数据承载在从所述光分配网络接 收的所述光波上， 形成上行信号， 并将所述上行信号发送至所述光分配网络； 例如， 所述的 ONU13可以包括： 第二 OFDM调制模块 131和发射模块 132; 该第二 OFDM调制模块 131可以用于对 ONU的上行数据进行 OFDM 调制， 发射模块 132用于将 OFDM调制后的上行数据承载在从 ODN接收的 所述光波上形成上行信号， 并将该上行信号发送至所述 ODN。
本实施例的无源光网络通信系统的工作原理如下：为了实现每个 ONU工 作在不同的波长， 本实施例在 OLT11中设置了宽谱光源 112, 将该宽谱光源 112产生的宽语光发送至 ODN, 由 ODN中的 AWG121将该宽语光分割成多 个波长互不相同的光波， 并将该多个光波发送至多个 ONU; 后续 ONU在进 行上行传输时， 上行信号对应的波长就是该 ONU预先接收到的光波的波长， 从而使得上行传输时各 ONU的上行信号的波长也互不相同， 就不会产生 OBI, 解决了光差拍干扰问题， OLT中的第一 OFDM调制模块 111可以对接 收的多个 ONU的上行信号进行解调，分别得到该多个 ONU对应的上行数据。
需要说明的是， 本实施例的无源光网络通信系统， 在图 1中仅示出了该 无源光网络通信系统所包括的部分模块， 例如， 阵列波导光栅、 宽谱光源等， 但是在具体实施中，本领域技术人员可以理解，该系统中的各部分，例如 OLT、 ODN、 ONU, 其并不局限于仅包括图 1中所示的模块， 比如， ODN中还可 以包括分光器（splitter )等。
在本实施例所述的无源光网络通信系统中，只需要在 OLT中设置一个宽 谱光源， 并与 ODN中的 AWG相配合， 由 AWG将该宽语光源产生的宽谱光 分割成多个光波注入各 ONU即可，相当于只设置一个宽语光源和一个 AWG, 该宽谱光源和 AWG的成本低，所以比现有技术中的在每个 ONU中都设置发 射机、 或者釆用昂贵的可调谐发射机都成本低， 并且， 釆用上述宽谱光源和 AWG的组合方式实现各 ONU的波长不同， 实现方法很简单， 比现有技术中 的 ONU釆用载波抑制的光调制方式以及 OLT端进行相干接收，要简单易行， 更容易实施， 所以成本也较低。
下面通过实施例二和实施例三， 分别描述两种可选的系统结构： 实施例二
图 2为本发明无源光网络通信系统另一实施例的结构示意图， 本实施例 是在图 1所示结构的基础上， 对无源光网络通信系统的结构进一步细化。
如图 2所示， 该系统的 OLT11还包括： 发射模块（ Optical Transmitter, 在图 2中以 Optical Tx简示） 113 (可以称为第一发射模块） 、 以及第一接收 模块（Optical Receiver, 在图 2中以 Optical Rx简示） 114。 其中， 发射模块 113可以产生具有第二波长的下行光， 并将 OFDM调制后的下行数据承载在 该下行光上形成下行信号， 所述的 OFDM调制后的下行数据是电信号， 而承 载在下行光上形成的下行信号是光信号， 所以该发射模块 113相当于是进行 光电转换，将电信号转换为光信号后才能在主干光纤传输。第一接收模块 114 用于接收多个 ONU的上行信号， 即 ONU的上行信号在进入 OLT后是要被 该第一接收模块 114接收的， 由该第一接收模块 114将上行信号发送至第一 OFDM调制模块 111进行解调获得上行数据。 所述 OLT11中的第一 OFDM调制模块 111 ,具体可以包括： 第一 OFDM 调制发送单元（ OFDM Transmitter, 在图 2中以 OFDM Tx简示） 115和第一 OFDM调制接收单元（ OFDM Receiver, 在图 2中以 OFDM Rx简示） 116; 其中， 第一 OFDM调制发送单元 115用于将要发送至多个 ONU的下行数据 进行 OFDM调制， 并将 OFDM调制后的下行数据发送至发射模块 113; 第一 OFDM调制接收单元 116用于对第一接收模块 114接收的各 ONU的上行信 号进行 OFDM解调， 分别得到各 ONU对应的上行数据。
其中， 上述的 OFDM调制、 以及 OFDM解调的方法是釆用常规的基于 OFDM的数据调制方式。 例如， 当 OLT11要向 ONU发送下行数据时， 第一 OFDM调制发送单元会将高速串行的下行数据先转换为低速并行数据， 然后 并行数据被映射成多个调制矢量，再进行快速傅里叶逆变换，变换后添加 CP, 最后作并串变换和数模转换， 即可得到 OFDM调制后的下行数据。 后续发射 模块 113再将该 OFDM调制后的下行数据承载在下行光上形成下行信号， 实 现电信号到光信号的转换， 发送至主干光纤进行传输。 当 OLT11接收 ONU 发送的上行信号时， 在第一接收模块进行光电转换后， 第一 OFDM调制接收 单元会先对上行信号作模数转换和串并变换， 产生时间样值序列， 再去除 CP 后再作快速傅里叶变换， 对变换所得的矢量序列作适当的数字信号处理， 包 括信道均衡、 前向纠错等， 再进行解调， 映射产生并行数据， 最后用并串变 换还原成串行数据即得到 ONU的上行数据。
所述 OLT11中还包括： 第一波分复用器 117和环形器（Circuit ) 118; 其中， 第一波分复用器 117用于将下行信号与宽谱光进行复用， 下行信号和 宽谱光的波段不同， 如下行信号是 L波段， 宽谱光为 C波段； 环形器 118用 于将复用后的下行信号与宽谱光发送至 ODN。所述的环形器 118适用于控制 信号的流向的， 进入该环形器 118的信号只能按照一个方向行进例如按照图 2中所示的箭头方向； 例如， 从： 第一波分复用器 117进入环形器 118的下 行信号只能沿箭头方向从主干光纤的端口 F输出，下行信号在主干光纤 14传 输； 从主干光纤 14的端口 F接收的 ONU的上行信号， 也只能沿箭头方向向 下传输至第一接收模块 114。
所述 ODN12中还包括： 第二波分复用器 122和分光器 123。 其中， 第二 波分复用器 122用于将下行信号与宽谱光解复用， 即将下行信号与宽谱光分 开，并将宽谱光发送至 AWG121 ;分光器 123用于下行信号广播至多个 ONU, 具体是将所述第二波分复用器 122解复用后的下行信号， 分割成分别与至少 一个光网络单元对应的至少一个下行信号， 该分割成的多个下行信号实际上 是分别承载有对应的 ONU的下行数据的信号，并将所述至少一个下行信号对 应广播至至少一个 ONU, 即将承载有某个 ONU的下行数据的下行信号对应 发送至该 ONU。该 ODN12中还包括： 波分复用器 124,用于将通过 AWG121 和分光器 123处理后的光波复用在一起， 发送至 ONU13。
所述的 ONU13中还包括： 第二接收模块（Optical Receiver ) 133 , 可以 接收分光器 123广播发送的下行信号， 并将该下行信号发送至第二 OFDM调 制模块 131进行 OFDM解调。该 ONU 13中的第二 OFDM调制模块 131具体 可以包括： 第二 OFDM调制发送单元 (OFDM Transmitter) 134和第二 OFDM 调制接收单元 (OFDM Receiver) 135。 其中， 第二 OFDM调制发送单元 134用 于对 ONU的上行数据进行 OFDM调制，并将 OFDM调制后的所述上行数据 发送至发射模块 132 (可以称为第二发射模块） ； 第二 OFDM调制接收单元 135用于对第二接收模块 133接收的下行信号进行 OFDM解调， 得到与该 ONU对应的下行数据。具体的 OFDM调制以及 OFDM解调的方法与 OLT的 处理相同， 不再赘述。
本实施例中， ONU13中的发射模块 132可以为反射型调制器（ Reflective Modulator, 简称： R-Mod ) , 该反射型调制器例如为， 反射式半导体放大器 (Reflective Semiconductor Optical Amplifier, 简称： RSOA)或者反射式电致吸 收调制器 (Reflective Electro-Absorption Modulator, 简称： REAM)等。 釆用该 反射型调制器的优点是:每个 ONU不需要限定为必须发射特定波长的上行光 波， 不限制 ONU的发射波长， 该发射模块 132可以在上述的 AWG注入的对 应某种波长的光波的作用下， 将上行光波的波长锁定为所述的某种波长， 即 发射模块 132是根据预先注入的光波将上行光波的波长锁定为该 ONU对应的 无色化使得在进行各 ONU的部署时， 不被波长对应所限制， 使得 ONU部署 更加灵活。
如图 2所示，本实施例的 ONU13可以有多个，例如第一 ONU、第二 ONU、 ONU3等， 在图 2中只示出了第一 ONU的结构， 第二 ONU、 ONU3等其他 ONU的结构与第一 ONU相同， 未示出。
下面从下行传输、 以及上行传输两个方向的工作流程， 对本实施例的无 源光网络通信系统的工作原理进行说明， 其中， 上、 下行信号的波长不同， 下行信号波长设为 λ ύ, 并假设有 32个 ONU, 宽谱光源发出的宽谱光的波长 设为 λ u ,被 AWG分割成的分别与 32个 ONU对应的上行信号波长设为 λ ul , 入 u2， ， 入 u32。
下行传输：
首先， OLT11中的 OFDM Transmitterl 15对要发送至各 ONU的下行数据 进行 OFDM调制， 调制后的下行数据是电信号， 在发送至 Optical
Transmitterl 13之后， Optical Transmitterl 13将该电信号转换为光信号， 具体 是将调制后的下行数据承载在下行光上形成下行信号， 该下行信号的波长是
A d。
接着， 该下行信号和 BLS112发出的宽谱光（该宽谱光的波长为 u ) ― 起通过第一波分复用器 117复用， 再经过环形器 118进入主干光纤 14。 主干 光纤 14传输部分的 ODN12, 上述经过复用的下行信号和宽谱光被第二波分 复用器 122解复用， 宽谱光被 AWG121分割成 32个分离的光波， 其波长分 别为 λ 1, λ υ2, ... ... , λ υ32, 再分别注入到 32个 ONU的反射型调制器即发 射模块 132中， 例如， 波长为 ul的光波被注入到第一 ONU的反射型调制器 中， 使得锁定各个 ONU的上行信号波长分别为 ul , λ υ2, ……， λ υ32, 各 ONU的上行信号将分别承载在这 32个注入锁定的光波上。
同时， 被第二波分复用器 122解复用后得到的下行信号进入分光器 ( splitter ) 123中， 再由分光器 123广播给所有的 ONU, 具体是通过波分复 用器 124,将 AWG121和分光器 123处理后的广播复用在一起后发送至 ONU。 ONU的 Optical Receiver 133接收到该下行信号后， 对该下行信号进行光电转 换， 将光信号转换为电信号， 并将该电信号送入 OFDM Receiverl35。 OFDM Receiverl35对下行信号进行 OFDM解调过滤出该 ONU对应的子信道的数 据。 由上述可知， 该系统的下行方向釆用 TDM+OFDM的方式。
上行传输： 并将 OFDM调制后的上行数据发送至发射模块（ R-Mod ) 132。 发射模块 132 将所述上行数据承载在预先注入的光波上形成上行信号， 该上行信号的波长 是注入的光波波长，例如，第一 ONU的发射模块 132发出的上行信号是波长 为 ul上的光波。
接着， 各 ONU发出的上行 32个上行信号光波被 ODN12中的 AWG121 复用，再经过第二波分复用器 122、主干光纤 14进入 OLT11中。经过 OLT11 中的环形器 118入射到 OLT中的 Optical Receiverl 14 (即相当于光电探测器 ( Photo Detector, 简称： PD ) )。 该 Optical Receiverl 14在 OLT中只有一个， 其接收来自所有 0NU的上行信号；由于这 32个 0NU的波长 λ ul , λ u2, ... ... , 入 u32各不相同， 所以在 Optical Receiverl 14上不会产生光差拍干扰 0BI。 Optical Receiverl 14对上行信号进行光电转换， 将光信号转换为电信号。
然后 , 电信号形式的上行信号进入 0LT的 OFDM Receiverl 16中进行解 调， 恢复出每个 ONU对应的子信道中的数据， 即上行方向釆用
WDM+OFDMA的方式。
其中，在上述的下行传输和上行传输的工作流程的描述中，所述的 OFDM 调制或解调技术是这样的：
OFDM是一种多载波调制技术， 其基本思想是在频域内将信道划分成许 多正交的子信道， 在每个子信道上使用一个子载波进行调制， 子载波可釆用 正交相移键控（Quadrature Phase Shift Keying, 简称： QPSK ) 、 正交幅度调 制 ( Quadrature Amplitude Modulation , 简称： QAM )等高阶调制提高系统容 量， 并且每个子载波并行传输， 这种并行传输技术可以将高速的数据流分配 到若干个子载波低速传输。 OFDM相对于一般的多载波传输的不同之处在于 它允许子载波频谱部分重叠， 只要满足子载波之间的相互正交， 则可以从混 叠的子载波上分离出来数据信号。 由于 OFDM允许子载波频谱混叠， 其频谱 效率大大提高， 因而是一种高效的调制方式。
当前的 OFDM发送和接收机制都是基于快速傅里叶变换 (Fast Fourier
Transform, 简称： FFT), 用数字信号处理 (Digital Signal Processing, 简称： DSP)芯片来实现。 在发送端， 高速的串行数据先被变成低速的并行数据， 然 后并行数据被映射成多个调制矢量， 再进行多点快速傅里叶逆变换。 变换后 添加 CP, 最后作并串变换和数模转换， 产生连续的 OFDM信号向信道发送。 在接收端， 先对接收信号作模数转换 (Analog Digital Conversion, 简称： ADC) 和串并变换， 产生时间样值序列， 再去除 CP后再作多点快速傅里叶变换 (FFT)。 对变换所得的矢量序列作适当的数字信号处理， 包括信道均衡、 前向 纠错等， 再进行解调， 映射产生并行数据， 最后用并串变换还原成串行数据。
实施例三
图 3为本发明无源光网络通信系统又一实施例的结构示意图， 本实施例 又提供了一种可选的无源光网络通信系统结构， 该结构与实施例二中的系统 结构的区别在于， 本实施例的第一 OFDM调制模块包括多个第一 OFDM调 制发送单元 OFDM Tx, 所述第一发射模块 Optical Tx的数量也为多个； 一个 OFDM Tx和一个 Optical Tx组成一个发射单元， 所述发射单元的数量与所述 多个光网络单元 ONU的数量相等。本实施例的多个所述发射单元，用于发送 分别承载有与 ONU对应的下行数据的多个下行信号，所述下行信号具有与所 述光网络单元对应的第二波长。
如图 3所示， 本实施例的 OLT中 , OFDM Tx和 Optical Tx分别都具有 多个 , 具体是包括与 ONU数量相等的多个 OFDM Tx和 Optical Tx。 例如 , 若 ONU的数量有 32个，该 OFDM Tx和 Optical Tx的数量也分别具有 32个。 每个 OFDM Tx和 Optical Tx对应的发射单元， 用于将对应其中一个 ONU的 下行数据进行 OFDM调制，并承载在具有与该 ONU对应的波长的下行光上， 例如图 3中的 d l , λ ά 2等， 这些 d l, λ ά 2等可以均称为第二波长。
本实施例的 OLT还包括： 阵列波导光栅 AWG, 用于将多个所述下行信 号复用后发送至所述第一波分复用器 117。
在下行传输时， 所述的 32个 OFDM Tx和 Optical Tx产生的信号中 , 每 个 Optical Tx输出的光信号的波长是不同的， 例如， d l, X d 2, ··· , X d 32, 该 32个 Optical Tx输出的光信号分别对应不同的 ONU。 将经过 OLT中的 AWG复用后， 输出复用后的下行信号， 信号波长是 d, 该波长为入(1的下行 信号和 BLS发出的宽谱光（该宽谱光的波长为 λ u )一起通过第一波分复用器 117复用， 再经过环形器 118进入主干光纤 14。
在 ODN12中， 本实施例的 ODN12中可以不包括分光器（splitter ) , 由 AWG121将上述的主干光纤 14的下行信号和宽谱光分割；具体的是, AWG121 将宽谱光分割成 32个分离的光波， 其波长分别为 λ υ λ υ2, ... ... , λ υ32, 并将下行信号解复用为 OLT中对应的 32个 OFDM Tx和 Optical Tx产生的下 行信号， 所述解复用后的各下行信号与分割后的宽谱光一起， 分别注入到 32 个 ONU的反射型调制器即发射模块 132中。 例如， 波长为 λ 1的光波被注入 到第一 ONU的反射型调制器中， 使得锁定各个 ONU的上行信号波长分别为 λ υ λ ^, ... ... , λ υ32, 各 ONU的上行信号将分别承载在这 32个注入锁定 的光波上。
在上行传输时，各 ONU将上行数据承载在预先注入的光波上形成上行信 号， 发出的上行 32个上行信号光波被 ODN12中的 AWG121复用， 经过主干 光纤 14进入 OLT11中。经过 OLT11中的环形器 118入射到 OLT中的 Optical Receiverl 14, 该 Optical Receiver 114在 OLT中只有一个， 其接收来自所有 ONU的上行信号； 由于这 32个 ONU的波长 ul , λ ^, ... ... , λ υ32各不相 同， 所以在 Optical Receiverl 14上不会产生光差拍干扰 OBI。 Optical
Receiverl 14对上行信号进行光电转换， 将光信号转换为电信号。 电信号形式 的上行信号进入 OLT的 OFDM Receiverl 16中进行解调， 恢复出每个 ONU 对应的子信道中的数据。
实施例四
图 4为本发明光线路终端实施例的结构示意图， 如图 4所示， 该光线路 终端 OLT可以包括： 宽谱光源 41、 第一正交频分复用调制模块 42和信号发 射模块 43; 其中，
所述宽谱光源 41 , 用于产生具有第一波长的所述宽谱光；
所述第一正交频分复用调制模块 42, 用于将待发送至所述至少一个光网 络单元的下行数据进行正交频分复用调制； 以及， 用于将从至少一个光网络 单元接收的上行信号进行正交频分复用解调， 分别得到所述至少一个光网络 单元对应的上行数据；
信号发射模块 43 , 用于产生具有第二波长的下行光， 并通过所述下行光 承载待发送至所述至少一个光网络单元的经过正交频分复用调制的下行数据 形成下行信号； 并将所述下行信号与所述宽谱光进行复用后发送至所述光分 配网络， 以使得所述光分配网络将所述宽谱光分割成至少一个光波分别发送 至至少一个光网络单元，并使得所述光网络单元通过所述光波承载上行数据。
可选的，该信号发射模块 43可以包括：第一发射模块和第一波分复用器； 该第一发射模块和第一波分复用器的结构可以参见系统实施例； 所述第一发射模块， 用于产生具有第二波长的下行光， 并通过所述下行 光承载待发送至所述至少一个光网络单元的经过正交频分复用调制的下行数 据形成下行信号；
所述第一波分复用器， 用于将所述下行信号与所述宽谱光进行复用后发 送至所述光分配网络， 以使得所述光分配网络将所述宽谱光分割成至少一个 光波分别发送至至少一个光网络单元， 并使得所述光网络单元通过所述光波 承载上行数据。
进一步的， 可以参见系统实施例中的图 3所示， 所述第一正交频分复用 调制模块包括多个第一正交频分复用调制发送单元， 所述第一发射模块的数 量为多个； 一个所述第一正交频分复用调制发送单元和一个第一发射模块组 成一个发射单元， 所述发射单元的数量与多个光网络单元的数量相等； 多个 所述发射单元， 用于发送分别承载有与所述光网络单元对应的下行数据的多 个下行信号， 所述下行信号具有与所述光网络单元对应的第二波长。
进一步的， 可以参见系统实施例中的图 2所示， 所述第一正交频分复用 调制模块包括一个第一正交频分复用调制发送单元，以及一个第一发射模块； 一个所述第一正交频分复用调制发送单元和一个第一发射模块连接组成一个 发射单元；
所述发射单元， 用于将待发送至所述至少一个光网络单元的下行数据进 行正交频分复用调制后，均承载在所述具有第二波长的下行光形成下行信号。
本实施例的光线路终端， 通过设置宽谱光源产生宽谱光， 可以使得光分 配网能够通过分割该宽谱光而产生与 ONU对应的光波，进而使得将光波注入 到 ONU作为 ONU上行数据的承载光波， 从而能够降低 ONU的成本。
实施例五
图 5为本发明无源光网络通信方法一实施例的流程示意图， 该方法是 OLT执行， 本实施例仅对该方法做简单描述， 具体可以结合参见系统实施例 中的原理说明； 如图 5所示， 该方法可以包括：
501、 产生具有第一波长的宽谱光、 以及具有第二波长的下行光；
502、对待发送至所述至少一个光网络单元的下行数据进行正交频分复用 调制， 并将调制后的所述数据承载在所述下行光形成下行信号；
503、将所述宽谱光和下行信号发送至光分配网络， 以使得所述光分配网 络将所述宽谱光分割成至少一个光波分别发送至至少一个光网络单元， 并使 得所述光网络单元通过所述光波承载上行数据；
504、接收所述至少一个光网络单元发送的上行信号， 并对所述上行信号 通过正交频分复用解调 ,分别得到所述至少一个光网络单元对应的上行数据。
进一步的， 所述产生具有第二波长的下行光， 包括： 产生至少一个下行 光， 所述至少一个下行光分别具有与所述至少一个光网络单元对应的波长； 所述对待发送至所述至少一个光网络单元的下行数据进行正交频分复用 调制， 并将调制后的所述数据承载在所述下行光形成下行信号， 包括：
分别对待发送至所述至少一个光网络单元的下行数据进行正交频分复用 调制， 并将调制后的所述数据分别承载在与所述光网络单元对应的至少一个 下行光上， 形成与所述至少一个光网络单元对应的多个下行信号。
实施例六
图 6为本发明无源光网络通信方法另一实施例的流程示意图， 该方法是 ONU执行， 本实施例仅对该方法做简单描述， 具体可以结合参见系统实施例 中的原理说明； 如图 6所示， 该方法可以包括：
601、 接收光线路终端发送的下行信号和光波；
所述下行信号承载有所述光线路终端发送的经过正交频分复用调制的下 行数据， 所述下行数据承载在具有第二波长的下行光， 所述光波是通过对所 述光线路终端产生的具有第一波长的宽谱光分割得到；
602、 对所述下行信号进行正交频分复用解调， 得到所述下行数据；
603、将待发送至所述光线路终端的上行数据承载在所述光波上， 形成上 行信号， 发送至所述光线路终端。
本实施例的无源光网络通信方法， ONU通过接收光线路终端产生的宽谱 光分割得到的光波， 作为承载上行数据的光波， 相对于现有技术实现简单， 降低了 ONU的成本。
实施例七
图 7为本发明无源光网络通信方法又一实施例的流程示意图， 本实施例 主要是从系统的角度对该无源光网络通信方法简单说明。 如图 7所示， 包括：
701、 光线路终端 OLT中的宽谱光源产生具有第一波长的宽谱光、 以及 具有第二波长的下行光，所述 OLT通过所述下行光承载待发送至所述至少一 个光网络单元的经过正交频分复用调制的下行数据形成下行信号， 并将所述 宽谱光和下行信号发送至光分配网络 ODN;
702、 所述 ODN中的阵列波导光栅 AWG将所述宽谱光分割成分别与多 个光网络单元 ONU对应的多个光波，所述多个光波的波长互不相同，并将所 述多个光波和所述下行信号分别发送至所述多个 ONU;
703、 所述 ONU对接收到的下行信号进行正交频分复用解调得到与所述 光网络单元对应的下行数据； 并对要发送至 OLT的上行数据进行 OFDM调 制， 将 OFDM调制后的上行数据承载在从所述 ODN接收的所述光波上， 形 成上行信号， 将所述上行信号发送至所述 ODN;
704、 所述 ODN通过所述 AWG对所述多个 ONU发送的上行信号复用 后发送至所述 OLT;
705、 OLT通过对接收的所述多个 ONU的上行信号进行 OFDM解调， 分别得到所述多个 ONU对应的上行数据。
本领域普通技术人员可以理解： 实现上述各方法实施例的全部或部分步 骤可以通过程序指令相关的硬件来完成。 前述的程序可以存储于一计算机可 读取存储介质中。 该程序在执行时， 执行包括上述各方法实施例的步骤； 而 前述的存储介质包括： ROM, RAM, 磁碟或者光盘等各种可以存储程序代码 的介质。
最后应说明的是： 以上各实施例仅用以说明本发明的技术方案， 而非对 其限制； 尽管参照前述各实施例对本发明进行了详细的说明， 本领域的普通 技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改， 或者对其中部分或者全部技术特征进行等同替换； 而这些修改或者替换， 并 不使相应技术方案的本质脱离本发明各实施例技术方案的范围。

Claims

权 利 要 求 书
1、 一种无源光网络通信系统， 其特征在于， 包括： 光线路终端、 光分配 网络和至少一个光网络单元， 所述光线路终端通过光分配网络与所述至少一 个光网络单元进行连接；
所述光线路终端， 用于产生具有第一波长的宽谱光、 以及具有第二波长 的下行光， 通过所述下行光承载待发送至所述至少一个光网络单元的经过正 交频分复用调制的下行数据形成下行信号， 并将所述宽谱光和下行信号发送 至所述光分配网络； 以及， 用于接收所述至少一个光网络单元发送的上行信 号， 并对所述上行信号通过正交频分复用解调， 分别得到所述至少一个光网 络单元对应的上行数据；
所述光分配网络， 用于将从所述光线路终端接收的宽谱光分割成分别与 至少一个光网络单元对应的至少一个光波， 并将所述至少一个光波和所述下 行信号分别发送至对应的所述至少一个光网络单元； 以及， 用于通过对所述 至少一个光网络单元发送的上行信号进行复用后发送至所述光线路终端； 所述至少一个光网络单元， 用于接收所述下行信号， 并对所述下行信号 进行正交频分复用解调得到与所述光网络单元对应的下行数据； 以及， 将待 发送至所述光线路终端的经过正交频分复用调制的上行数据承载在从所述光 分配网络接收的所述光波上， 形成上行信号， 并将所述上行信号发送至所述 光分配网络。
2、 根据权利要求 1所述的无源光网络通信系统， 其特征在于， 所述光线 路终端具体包括： 宽谱光源和第一正交频分复用调制模块；
所述宽谱光源， 用于产生具有第一波长的所述宽谱光；
所述第一正交频分复用调制模块， 用于将待发送至所述至少一个光网络 单元的下行数据进行正交频分复用调制； 以及， 用于对接收的至少一个光网 络单元发送的上行信号进行正交频分复用解调， 分别得到所述至少一个光网 络单元对应的上行数据。
3、 根据权利要求 2所述的无源光网络通信系统， 其特征在于， 所述光线 路终端还包括： 第一发射模块和第一波分复用器；
所述第一发射模块， 用于将所述第一正交频分复用调制模块进行正交频 分复用调制后的下行数据承载在所述下行光上形成下行信号； 所述第一波分复用器， 用于将所述下行信号与所述宽谱光进行复用后发 送至所述光分配网络；
所述光分配网络还包括： 第二波分复用器；
所述第二波分复用器， 用于将所述下行信号与所述宽谱光进行解复用， 以使得所述光分配网络对解复用后的所述宽谱光进行分割。
4、 根据权利要求 1所述的无源光网络通信系统， 其特征在于， 所述光分 配网络具体包括： 阵列波导光栅；
所述阵列波导光栅， 用于将所述光线路终端发送的宽谱光分割成与至少 一个光网络单元对应的至少一个光波； 以及， 用于对所述至少一个光网络单 元发送的上行信号进行复用。
5、 根据权利要求 3所述的无源光网络通信系统， 其特征在于， 所述光分 配网络还包括： 分光器；
所述分光器， 用于将所述第二波分复用器解复用后的下行信号， 分割成 分别与至少一个光网络单元对应的至少一个下行信号， 并将所述至少一个下 行信号对应广播至所述至少一个光网络单元。
6、 根据权利要求 3所述的无源光网络通信系统， 其特征在于， 所述第一 正交频分复用调制模块包括多个第一正交频分复用调制发送单元， 所述第一 发射模块的数量为多个； 一个所述第一正交频分复用调制发送单元和一个第 一发射模块组成一个发射单元， 所述发射单元的数量与所述多个光网络单元 的数量相等；
多个所述发射单元， 用于发送分别承载有与所述光网络单元对应的下行 数据的多个下行信号，所述下行信号具有与所述光网络单元对应的第二波长。
7、 一种光线路终端， 其特征在于， 包括： 宽谱光源、 第一正交频分复用 调制模块和信号发射模块；
所述宽谱光源， 用于产生具有第一波长的所述宽谱光；
所述第一正交频分复用调制模块， 用于将待发送至所述至少一个光网络 单元的下行数据进行正交频分复用调制； 以及， 用于将从至少一个光网络单 元接收的上行信号进行正交频分复用解调， 分别得到所述至少一个光网络单 元对应的上行数据；
信号发射模块， 用于产生具有第二波长的下行光， 并通过所述下行光承 载待发送至所述至少一个光网络单元的经过正交频分复用调制的下行数据形 成下行信号； 并将所述下行信号与所述宽谱光进行复用后发送至所述光分配 网络， 以使得所述光分配网络将所述宽谱光分割成至少一个光波分别发送至 至少一个光网络单元， 并使得所述光网络单元通过所述光波承载上行数据。
8、 根据权利要求 7所述的光线路终端， 其特征在于， 所述第一正交频分 复用调制模块包括多个第一正交频分复用调制发送单元， 所述第一发射模块 的数量为多个； 一个所述第一正交频分复用调制发送单元和一个第一发射模 块组成一个发射单元， 所述发射单元的数量与多个光网络单元的数量相等； 多个所述发射单元， 用于发送分别承载有与所述光网络单元对应的下行 数据的多个下行信号，所述下行信号具有与所述光网络单元对应的第二波长。
9、 根据权利要求 7所述的光线路终端， 其特征在于， 所述第一正交频分 复用调制模块包括一个第一正交频分复用调制发送单元， 以及一个第一发射 模块； 一个所述第一正交频分复用调制发送单元和一个第一发射模块连接组 成一个发射单元；
所述发射单元， 用于将待发送至所述至少一个光网络单元的下行数据进 行正交频分复用调制后，均承载在所述具有第二波长的下行光形成下行信号。
10、 一种无源光网络通信方法， 其特征在于， 包括：
产生具有第一波长的宽谱光、 以及具有第二波长的下行光；
对待发送至所述至少一个光网络单元的下行数据进行正交频分复用调 制， 并将调制后的所述数据承载在所述下行光形成下行信号；
将所述宽谱光和下行信号发送至光分配网络， 以使得所述光分配网络将 所述宽谱光分割成至少一个光波分别发送至至少一个光网络单元， 并使得所 述光网络单元通过所述光波承载上行数据；
接收所述至少一个光网络单元发送的上行信号， 并对所述上行信号通过 正交频分复用解调， 分别得到所述至少一个光网络单元对应的上行数据。
1 1、 根据权利要求 10所述的方法， 其特征在于， 所述产生具有第二波长 的下行光， 包括： 产生至少一个下行光， 所述至少一个下行光分别具有与所 述至少一个光网络单元对应的波长；
所述对待发送至所述至少一个光网络单元的下行数据进行正交频分复用 调制， 并将调制后的所述数据承载在所述下行光形成下行信号， 包括： 分别对待发送至所述至少一个光网络单元的下行数据进行正交频分复用 调制， 并将调制后的所述数据分别承载在与所述光网络单元对应的至少一个 下行光上， 形成与所述至少一个光网络单元对应的多个下行信号。
12、 一种无源光网络通信方法， 其特征在于， 包括：
接收光线路终端发送的下行信号和光波， 所述下行信号承载有所述光线 路终端发送的经过正交频分复用调制的下行数据， 所述下行数据承载在具有 第二波长的下行光， 所述光波是通过对所述光线路终端产生的具有第一波长 的宽谱光分割得到；
对所述下行信号进行正交频分复用解调， 得到所述下行数据； 并将待发 送至所述光线路终端的上行数据承载在所述光波上， 形成上行信号， 发送至 所述光线路终端。
PCT/CN2012/083577 2012-10-26 2012-10-26 无源光网络通信方法和系统、光线路终端 WO2014063349A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201280001536.4A CN103109476B (zh) 2012-10-26 2012-10-26 无源光网络通信方法和系统、光线路终端
PCT/CN2012/083577 WO2014063349A1 (zh) 2012-10-26 2012-10-26 无源光网络通信方法和系统、光线路终端

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2012/083577 WO2014063349A1 (zh) 2012-10-26 2012-10-26 无源光网络通信方法和系统、光线路终端

Publications (1)

Publication Number Publication Date
WO2014063349A1 true WO2014063349A1 (zh) 2014-05-01

Family

ID=48316007

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2012/083577 WO2014063349A1 (zh) 2012-10-26 2012-10-26 无源光网络通信方法和系统、光线路终端

Country Status (2)

Country Link
CN (1) CN103109476B (zh)
WO (1) WO2014063349A1 (zh)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014063349A1 (zh) * 2012-10-26 2014-05-01 华为技术有限公司 无源光网络通信方法和系统、光线路终端
CN104218997B (zh) * 2013-05-30 2017-02-08 上海贝尔股份有限公司 光网络单元与光线路终端
CN103402146B (zh) * 2013-07-10 2016-06-01 上海交通大学 正交频分复用无源光网络的下行节能的传输系统
CN104410453A (zh) * 2013-11-27 2015-03-11 南京世都科技有限公司 一种基于led脉冲的光纤通信方法及装置
WO2016106584A1 (zh) * 2014-12-30 2016-07-07 华为技术有限公司 无线前传无源光网络pon系统、光网络设备及方法
CN110324089B (zh) * 2018-03-30 2021-03-30 华为技术有限公司 一种无源光网络系统的信号传输方法及相关设备
CN113382316B (zh) * 2020-02-25 2023-11-17 华为技术有限公司 光线路终端、光网络单元及光通信系统
CN113572525B (zh) * 2020-04-28 2022-11-04 华为技术有限公司 一种通信方法及系统
CN113573176A (zh) * 2020-04-29 2021-10-29 华为技术有限公司 一种onu、olt、光通信系统及数据传输方法
CN112671502A (zh) * 2020-12-28 2021-04-16 武汉光迅科技股份有限公司 一种光线路终端

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101068129A (zh) * 2006-06-26 2007-11-07 华为技术有限公司 一种在wdm－pon中实现广播和/或组播业务的方法及其系统
CN101136701A (zh) * 2006-08-28 2008-03-05 华为技术有限公司 波分复用光接入传输系统及方法
US20100215368A1 (en) * 2009-02-24 2010-08-26 Nec Laboratories America, Inc. Single wavelength source-free ofdma-pon communication systems and methods
CN102238130A (zh) * 2011-08-05 2011-11-09 电子科技大学 基于ofdm的wdm-pon系统及下行数据传输方法
CN103109476A (zh) * 2012-10-26 2013-05-15 华为技术有限公司 无源光网络通信方法和系统、光线路终端

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101621350A (zh) * 2009-08-17 2010-01-06 华中科技大学 一种波分复用无源光网络
CN102075478A (zh) * 2009-11-24 2011-05-25 华为技术有限公司 无源光纤网络的信号处理方法、设备和系统
CN101986718B (zh) * 2010-11-16 2014-06-11 中兴通讯股份有限公司 无源光网络系统及系统中的光线路终端和波长路由单元
CN102710576B (zh) * 2012-06-15 2015-08-12 上海大学 相干检测无色正交频分复用波分复用无源光网络系统和传输方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101068129A (zh) * 2006-06-26 2007-11-07 华为技术有限公司 一种在wdm－pon中实现广播和/或组播业务的方法及其系统
CN101136701A (zh) * 2006-08-28 2008-03-05 华为技术有限公司 波分复用光接入传输系统及方法
US20100215368A1 (en) * 2009-02-24 2010-08-26 Nec Laboratories America, Inc. Single wavelength source-free ofdma-pon communication systems and methods
CN102238130A (zh) * 2011-08-05 2011-11-09 电子科技大学 基于ofdm的wdm-pon系统及下行数据传输方法
CN103109476A (zh) * 2012-10-26 2013-05-15 华为技术有限公司 无源光网络通信方法和系统、光线路终端

Also Published As

Publication number Publication date
CN103109476B (zh) 2016-12-14
CN103109476A (zh) 2013-05-15

Similar Documents

Publication Publication Date Title
WO2014063349A1 (zh) 无源光网络通信方法和系统、光线路终端
Cvijetic et al. 100 Gb/s optical access based on optical orthogonal frequency-division multiplexing
US9191116B2 (en) Orthogonal frequency division multiple access-passive optical network comprising optical network unit and optical line terminal
US8705970B2 (en) Method for data processing in an optical network, optical network component and communication system
US8934773B2 (en) Method for data processing in an optical network, optical network component and communication system
US9014568B2 (en) Next generation optical access network with centralized digital OLT
CN101714971B (zh) 无源光网络通信方法及系统、光网络单元和光线路终端
US8611743B2 (en) Optical-layer traffic grooming in flexible optical networks
US8897648B2 (en) Orthogonal frequency division multiple access time division multiple access-passive optical networks OFDMA TDMA PON architecture for 4G and beyond mobile backhaul
US20140072303A1 (en) Ultra dense wdm with agile and flexible dsp add-drop
CN102833206B (zh) 一种基于偏振复用频带间插的ofdma-pon系统
CN102035789A (zh) 基于光正交频分复用动态分配的无源接入网系统和方法
WO2013043127A1 (en) An integrated access network
WO2019042371A1 (zh) 光信号传输系统及光信号传输方法
US9112640B2 (en) Optical network unit, optical access network and a method for exchanging information
US8787762B2 (en) Optical-layer traffic grooming at an OFDM subcarrier level with photodetection conversion of an input optical OFDM to an electrical signal
CN102036134A (zh) 基于正交频分复用的汇聚式光接入网系统和方法
CN104038463B (zh) 基于四维动态资源分配的光接入网络系统
JP2010171788A (ja) 光信号送信方法、光通信システム、光送信器および光受信器
KR101462434B1 (ko) Ｏｆｄｍ 방식을 이용한 ｗｄｍ-ｐｏｎ 시스템
WO2007135407A1 (en) A method and apparatus for combining electrical signals
WO2014090043A1 (zh) Ofdm-pon系统及时钟信号的发送和提取方法
Kitayama et al. Green, elastic coherent IFDMA-PON for next-generation access network
Biswas et al. OFDMA-PON: High Speed PON Access System
JP2010171789A (ja) 光信号送信方法、光通信システム、光送信器および光受信器

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 201280001536.4

Country of ref document: CN

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12887233

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12887233

Country of ref document: EP

Kind code of ref document: A1