WO2023125528A1 - 光通信的方法、装置和*** - Google Patents

光通信的方法、装置和*** Download PDF

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Publication number
WO2023125528A1
WO2023125528A1 PCT/CN2022/142306 CN2022142306W WO2023125528A1 WO 2023125528 A1 WO2023125528 A1 WO 2023125528A1 CN 2022142306 W CN2022142306 W CN 2022142306W WO 2023125528 A1 WO2023125528 A1 WO 2023125528A1
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downlink
leaf node
subcarrier
signal
leaf
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PCT/CN2022/142306
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English (en)
French (fr)
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卢彦兆
张阔
李良川
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华为技术有限公司
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Publication of WO2023125528A1 publication Critical patent/WO2023125528A1/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
    • H04B10/25—Arrangements specific to fibre transmission
    • 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
    • H04B10/2575—Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier

Definitions

  • the present application relates to the technical field of optical communication, and in particular to an optical communication method, device and system.
  • Optical transmission systems have a variety of network architectures, and common network architectures include point-to-multipoint (PTMP) network architectures.
  • the point-to-multipoint network architecture refers to the transmission connection established between a single device and multiple devices.
  • the point-to-multipoint network architecture is widely used in passive optical network (passive optical network, PON) at present.
  • PON passive optical network
  • OLT optical line terminal
  • ONT optical network terminal
  • ONU optical network unit
  • wavelength division multiplexing technology is used for data transmission between the OLT and the ONT.
  • the OLT can emit light of multiple frequencies, and each frequency of light corresponds to an ONT, which serves as the optical carrier of the ONT.
  • the OLT modulates optical carrier signals of different frequencies for each ONT, and the wavelength division multiplexer connected to the OLT combines the optical carrier signals of multiple frequencies and transmits them to the ONT side through optical fibers.
  • the demultiplexer connected to the OLT separates the optical carrier signals of each frequency and transmits them to each ONT respectively.
  • the OLT needs to modulate optical carrier signals of different frequencies for each ONT.
  • the number of ONTs in the PON is generally large, and the OLT needs to emit light of various frequencies, which in turn requires multiple lasers. complex.
  • the present application provides an optical communication method, device and system, which can simplify the processing process of the OLT.
  • the present application provides a method for optical communication, which is performed by a central node in a PON, and the method includes:
  • the downlink frequency division multiplexing electrical signal Based on the center frequency of the downlink subcarrier corresponding to each leaf node and the coding power ratio on the corresponding downlink subcarrier, generate downlink frequency division multiplexing electrical signals corresponding to multiple downlink subcarriers, and each leaf node accesses the central node , at least one downlink subcarrier in the plurality of downlink subcarriers is encoded with data of a plurality of leaf nodes; the downlink frequency division multiplexing electrical signal is modulated onto the signal light of the first frequency to obtain a downlink frequency division multiplexing optical signal ; Send the downlink frequency division multiplexed optical signal.
  • each leaf node is a leaf node that accesses the central node.
  • the downlink subcarrier is a subcarrier used for downlink communication in the PON.
  • the central node encodes the data of multiple leaf nodes into downlink frequency division multiplexing electrical signals corresponding to multiple downlink subcarriers, sends the downlink frequency division multiplexing electrical signals through the signal light of the first frequency, and transmits the downlink frequency division multiplexing electrical signals in multiple downlink subcarriers Among the subcarriers, at least one downlink subcarrier is encoded with data of multiple leaf nodes. In this way, the central node only provides signal light of a single frequency without using multiple lasers, which simplifies the processing of the central node. Moreover, multiple leaf nodes can also share a downlink subcarrier, which can save spectrum resources.
  • the downlink frequency division multiplexing electrical signals corresponding to the multiple downlink subcarriers before generating the downlink frequency division multiplexing electrical signals corresponding to the multiple downlink subcarriers, it also includes: obtaining the signal-to-noise ratio of each leaf node on the downlink subcarriers that can be received; based on The signal-to-noise ratio of each leaf node on the downlink subcarriers that can be received determines the center frequency of the downlink subcarriers corresponding to each leaf node and the coding power ratio on the corresponding downlink subcarriers.
  • the coding power ratio corresponding to the first leaf node is lower than the coding power ratio corresponding to the second leaf node, and the signal-to-noise ratio corresponding to the first leaf node is higher than the signal-to-noise ratio corresponding to the second leaf node; Sending a first message, where the first message is used to indicate the center frequencies of the downlink subcarriers respectively corresponding to the leaf nodes.
  • the central node can use the signal-to-noise ratio of each leaf node on the downlink subcarrier that can be received to determine the center frequency of the downlink subcarrier corresponding to each leaf node and the corresponding downlink subcarrier. Coding power ratio, for multiple leaf nodes using the same downlink subcarrier, the coding power corresponding to the leaf node with high SNR is lower than the coding power corresponding to the leaf node with low SNR, so that the same downlink subcarrier is used It is easier for multiple leaf nodes to decode and obtain their own data.
  • the obtaining the signal-to-noise ratio of each leaf node on the downlink subcarriers that can be received includes: broadcasting power test optical signals corresponding to the plurality of downlink subcarriers; receiving the leaf node The received power corresponding to at least one downlink subcarrier to be sent; based on the received received power, determine the signal-to-noise ratio of each leaf node on the downlink subcarrier that can be received.
  • the central node can use the receiving power of each leaf node for the optical signal to obtain the signal-to-noise ratio of each leaf node on the downlink subcarriers that can be received.
  • the first message is also used to indicate the decoding mode of each leaf node on the corresponding downlink subcarrier; before sending the first message to each leaf node, it also includes: The center frequency of the downlink subcarrier corresponding to the leaf node and the coding power ratio on the corresponding downlink subcarrier determine the decoding method of each leaf node on the corresponding downlink subcarrier. How to decode data on subcarriers.
  • the central node can also determine the decoding mode of each leaf node on the corresponding downlink subcarrier, and notify the leaf node so that the leaf node can accurately decode and obtain its own data.
  • each downlink subcarrier corresponds to at most two leaf nodes; the difference between the signal-to-noise ratio of the first leaf node and the second leaf node on the target downlink subcarrier is greater than or equal to the target threshold.
  • the leaf nodes using the same downlink subcarrier have a relatively large SNR difference on the downlink subcarrier, making it easier for the leaf nodes using the same downlink subcarrier to decode and obtain their own data.
  • a center frequency of a downlink subcarrier corresponding to multiple leaf nodes is lower than a center frequency of a downlink subcarrier corresponding to one leaf node.
  • the SNR corresponding to the downlink subcarrier with high center frequency is generally lower than the SNR corresponding to the downlink subcarrier with low center frequency
  • the downlink subcarrier with low center frequency is more suitable for sharing by multiple leaf nodes. It is easier for leaf nodes of the same downlink subcarrier to decode and obtain their own data.
  • the method further includes: obtaining the signal-to-noise ratio of each leaf node on the uplink subcarrier that can be sent; Determine the center frequency of the uplink subcarrier corresponding to each leaf node and the coding power ratio on the corresponding uplink subcarrier.
  • the coding power ratio corresponding to the third leaf node is lower than that of the fourth leaf node
  • the corresponding coding power ratio, the signal-to-noise ratio corresponding to the third leaf node is higher than the signal-to-noise ratio corresponding to the fourth leaf node; send a second message to each leaf node, and the second message is used to indicate that each leaf node
  • the central node can use the signal-to-noise ratio of each leaf node on the uplink subcarrier that can be received to determine the center frequency of the uplink subcarrier corresponding to each leaf node and the corresponding uplink subcarrier. Coding power ratio, for multiple leaf nodes using the same uplink subcarrier, the coding power corresponding to the high SNR leaf node is lower than the coding power corresponding to the low SNR leaf node, so that the central node can distinguish the same Data of multiple leaf nodes corresponding to one uplink subcarrier.
  • the method further includes: receiving an uplink frequency division multiplexing optical signal; in the uplink frequency division multiplexing optical signal, obtaining the data of each leaf node through coherent reception. In this way, the central node can distinguish the data of each leaf node.
  • data of multiple leaf nodes is encoded on each of the at least one downlink subcarrier in a non-orthogonal coding manner based on sparse code division multiplexing (sparse code multiple access, SCMA).
  • SCMA sparse code multiple access
  • the present application provides a method for optical communication, which is executed by the first leaf node in the PON.
  • the method includes: receiving a downlink frequency division multiplexing optical signal sent by the central node, the downlink frequency division multiplexing optical signal modulated on the signal light of the first frequency; through the downlink frequency division multiplexing optical signal, obtain the downlink sub-carrier electrical signal corresponding to the first leaf node, and the downlink sub-carrier electrical signal is the downlink sub-carrier corresponding to the first leaf node
  • the first leaf node is any leaf node in the PON, and when there are multiple leaf nodes on the downlink subcarrier corresponding to the first leaf node, the first leaf node can obtain the downlink subcarrier first
  • the corresponding downlink sub-carrier electrical signal is then decoded to obtain its own data from the downlink sub-carrier electrical signal using a non-orthogonal decoding method.
  • the non-orthogonal decoding method is based on the multiple leaf nodes on the downlink sub-carrier
  • the encoding power ratio is determined. In this way, when the central node uses single-frequency signal light, the leaf nodes can also receive their own data, which can simplify the processing process of the central node.
  • multiple leaf nodes can share downlink subcarriers, which can also save spectrum resources.
  • the downlink frequency division multiplexed optical signal before receiving the downlink frequency division multiplexed optical signal, it also includes: receiving a first message, where the first message is used to indicate the downlink subcarriers and decoding modes corresponding to each leaf node, and each leaf node The leaf nodes are connected to the central node.
  • the plurality of leaf nodes include a first leaf node and a second leaf node; the non-orthogonal decoding method is based on decoding the downlink subcarrier electrical signal to obtain the data of the first leaf node , including: if the coding power ratio of the first leaf node is lower than the coding power ratio of the second leaf node, decoding the signal of the second leaf node from the downlink sub-carrier electrical signal, subtracting from the downlink sub-carrier electrical signal Remove the signal of the second leaf node to obtain the signal of the first leaf node; if the coding power ratio of the first leaf node is higher than the coding power ratio of the second leaf node, directly decode the downlink subcarrier electrical signal to obtain the first The signal of the leaf node; the data of the first leaf node is obtained by extracting the signal of the first leaf node.
  • the downlink subcarrier corresponding to the first leaf node is also encoded with the data of the second leaf node, since the coding power ratio used by the first leaf node and the second leaf node is the same, it can be based on the coding The power ratio is different, and its own data is decoded from the downlink subcarrier electrical signal.
  • the method further includes: receiving a second message, where the second message is used to indicate the center frequency of the uplink subcarrier corresponding to each leaf node and the coding power ratio on the corresponding uplink subcarrier,
  • the leaf nodes are connected to the central node; based on the encoding power ratio corresponding to the target uplink subcarrier of the first leaf node, an uplink electrical signal corresponding to the target uplink subcarrier is generated, and the target uplink subcarrier is the target uplink subcarrier corresponding to the first leaf node an uplink subcarrier; modulating the uplink electrical signal onto signal light of a second frequency to obtain an uplink optical signal, the second frequency being the same as the center frequency of the target uplink subcarrier; sending the uplink optical signal.
  • the first leaf node can use the uplink subcarrier and coding power ratio configured by the central node to send data uplink.
  • the downlink frequency division multiplexing optical signal before receiving the downlink frequency division multiplexing optical signal, it also includes: receiving the power test optical signal corresponding to the multiple downlink subcarriers broadcast by the central node; Received power corresponding to at least one downlink subcarrier; sending the received power to the central node.
  • the present application provides an optical communication device, and the device has a function of realizing the above-mentioned first aspect or any optional manner of the first aspect.
  • the device includes at least one module, and the at least one module is configured to implement the optical communication method provided in the first aspect or any optional manner of the first aspect.
  • the present application provides an optical communication device, which has the function of realizing the second aspect or any optional manner of the second aspect.
  • the device includes at least one module, and the at least one module is configured to implement the optical communication method provided in the second aspect or any optional manner of the second aspect.
  • the present application provides a central node, where the central node includes a processor and an optical modulator, and the processor is configured to process the electrical signal in the first aspect or any optional manner of the first aspect, For example, based on the signal-to-noise ratio, the center frequency of the downlink subcarrier corresponding to each leaf node and the coding power ratio on the corresponding downlink subcarrier are determined.
  • the light modulator is used to modulate the electrical signal onto signal light.
  • the present application provides a leaf node, the leaf node includes a processor and a detector, and the processor processes the electrical signal in the above-mentioned second aspect or any optional mode of the second aspect, for example , to obtain the data of the leaf node from the electrical signal, and the detector is used to receive the optical signal and convert the optical signal into an electrical signal.
  • the present application provides a computer-readable storage medium, in which at least one computer instruction is stored, and the computer instruction is read by a processor so that the central node can execute any of the above-mentioned first aspect or the first aspect. Electrical signals in an optional manner are processed.
  • the present application provides a computer-readable storage medium, in which at least one computer instruction is stored, and the computer instruction is read by a processor so that the leaf node can perform either the above-mentioned second aspect or the second aspect. Electrical signals in an optional manner are processed.
  • the present application provides an optical communication system, the system includes a central node and a plurality of leaf nodes, and the central node is used to realize the above-mentioned first aspect or any optional method of the first aspect.
  • An optical communication method, each leaf node is used to implement the optical communication method provided in the second aspect or any optional manner of the second aspect.
  • FIG. 1 is a schematic diagram of a logical architecture of a PON provided by an exemplary embodiment of the present application
  • FIG. 2 is a schematic structural diagram of a traditional PON provided by an exemplary embodiment of the present application
  • Fig. 3 is a schematic diagram of an architecture of uplink communication provided by an exemplary embodiment of the present application.
  • FIG. 4 is a schematic structural diagram of downlink communication provided by an exemplary embodiment of the present application.
  • FIG. 5 is a schematic structural diagram of a transmitter provided by an exemplary embodiment of the present application.
  • FIG. 6 is a schematic structural diagram of a receiver provided in an exemplary embodiment of the present application.
  • FIG. 7 is a schematic flowchart of a method for optical communication provided by an exemplary embodiment of the present application.
  • Fig. 8 is a schematic diagram of frequency spectrum and time multiplexing provided by an exemplary embodiment of the present application.
  • FIG. 9 is a schematic flowchart of an optical communication method provided by an exemplary embodiment of the present application.
  • FIG. 10 is a schematic flowchart of determining a downlink subcarrier corresponding to a leaf node provided by an exemplary embodiment of the present application.
  • FIG. 11 is a schematic flow diagram of determining the signal-to-noise ratio of a leaf node on a downlink subcarrier provided by an exemplary embodiment of the present application;
  • Fig. 12 is a schematic structural diagram of an optical communication device provided by an exemplary embodiment of the present application.
  • Fig. 13 is a schematic structural diagram of an optical communication device provided by an exemplary embodiment of the present application.
  • PON is a passive point-to-multipoint optical network formed by a passive optical splitter (splitter), which forms an optical distribution network (ODN) between point to multipoint ), see PON shown in Figure 1.
  • PON includes a central node and multiple leaf nodes.
  • the central node can be an OLT, and the leaf nodes can be ONT or ONU.
  • the central node can also be called a local end, and the leaf nodes can also be called a leaf end.
  • the process of sending data from the central node to the leaf node is called downlink communication, and the process of sending data from the leaf node to the central node is called uplink communication.
  • Frequency division multiplexing is to divide the total bandwidth used for the transmission channel into several sub-frequency bands (or called sub-channels), and each sub-channel transmits 1 optical signal. Frequency division multiplexing requires that the total frequency width is greater than the sum of the frequencies of each sub-channel. At the same time, in order to ensure that the signals transmitted in each sub-channel do not interfere with each other, isolation bands should be set between each sub-channel, thus ensuring that the optical signals of each channel Do not interfere with each other.
  • the carrier of the modulated signal is multiplied by the received modulated signal, and then the reception mode of the modulated signal is obtained through low-pass filtering.
  • the central node can emit multiple frequencies of light, and each frequency of light corresponds to a leaf node as the optical carrier of the leaf node.
  • the central node modulates optical carrier signals of different frequencies for each leaf node.
  • the wavelength division multiplexer connected to the central node combines the optical carrier signals of multiple frequencies and transmits them to the leaf node side through optical fibers.
  • the demultiplexer connected to the central node The optical carrier signals of each frequency are separated and transmitted to each leaf node respectively. In this way, the central node needs to modulate optical carrier signals of different frequencies for each leaf node.
  • the number of leaf nodes in PON is relatively large, and the central node needs to emit light of various frequencies, which in turn requires multiple lasers. The process is more complicated.
  • the leaf nodes send data to the central node by time division multiplexing (time division multiplexing, TDM), and the central node sends data to the leaf nodes by broadcast.
  • time division multiplexing is embodied in that each leaf node sends burst data packets lasting for a period of time.
  • the broadcast method is used to send data from the central node to the leaf node, the leaf node only extracts the data packets that belong to itself for a period of time, so it can also be considered as multiplexing in the time dimension.
  • data is transmitted in this way, so that the data of the leaf nodes cannot be sent in time.
  • data is also sent during the time period corresponding to other leaf nodes, which will cause the entire PON to fail.
  • the central node generates downlink frequency division multiplexed electrical signals corresponding to multiple downlink subcarriers, and at least one downlink subcarrier among the multiple downlink subcarriers is encoded with data of multiple leaf nodes. Then modulate the downlink frequency division multiplexing electrical signal onto the signal light of the first frequency to obtain a downlink frequency division multiplexing optical signal.
  • the central node sends downlink frequency division multiplexed optical signals. In this way, since the central node only provides signal light of one frequency, the central node only needs one laser for signal light, which simplifies the processing process of the central node.
  • At least one downlink sub-carrier is encoded with data of multiple leaf nodes, so that the data of multiple leaf nodes can be sent in parallel, and the delay in sending data of the leaf nodes can be reduced. Moreover, since each leaf node can send data at the same time, after some leaf nodes fail, the entire PON will not fail due to the faulty leaf nodes also sending out optical signals.
  • the downlink subcarriers are subcarriers used for downlink communication
  • the uplink subcarriers are subcarriers used for uplink communication.
  • the technical solution in this application can be applied to a communication system including a PON, and the embodiment of this application does not limit the communication system.
  • the communication system is code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (general packet radio service, GPRS), long term evolution (long term evolution, LTE) system or fifth-generation mobile communication technology (5th-generation, 5G), etc.
  • CDMA code division multiple access
  • WCDMA wideband code division multiple access
  • GPRS general packet radio service
  • LTE long term evolution
  • 5G fifth-generation mobile communication technology
  • the PON includes a central node and multiple leaf nodes, and the central node and multiple leaf nodes are connected through an ODN.
  • the central node can send out the signal light of the first frequency, and can send out the local oscillator light of the third frequency.
  • the local oscillator light can also be called the intrinsic light.
  • the signal light of the first frequency is used as an optical carrier in the downlink communication.
  • the local oscillator light of the third frequency is used for coherently receiving the optical signal sent by the leaf node in the uplink communication.
  • the leaf node can send out the signal light of the second frequency, and can send out the local oscillator light of the fourth frequency.
  • the signal light of the second frequency is used as the optical carrier in the uplink communication, and the local oscillator light of the fourth frequency is used for the downlink communication.
  • the second frequencies corresponding to different leaf nodes may be the same or different, and the fourth frequencies corresponding to different leaf nodes may be the same or different.
  • Figure 3 shows that the second frequency corresponding to leaf node 1 and leaf node 2 in the uplink communication is the same, and the second frequency corresponding to leaf node 1 and leaf node 3 is different, indicating that leaf node 1 and leaf node 2 share an uplink subcarrier , leaf node 3 does not share the uplink subcarrier with leaf node 1.
  • Figure 4 shows that the fourth frequency corresponding to leaf node 1 and leaf node 2 in the downlink communication is the same, and the fourth frequency corresponding to leaf node 1 and leaf node 3 is different, indicating that leaf node 1 and leaf node 2 share a downlink subcarrier , the leaf node 3 does not share the downlink subcarrier with the leaf node 1.
  • the leaf node there may be one or more second frequencies. When there is one second frequency, it means that the leaf node corresponds to one uplink subcarrier. When there are multiple second frequencies, it means that the leaf node A node corresponds to multiple uplink subcarriers.
  • the fourth frequency can be one or more. When the fourth frequency is one, it means that the leaf node corresponds to a downlink subcarrier. When there are multiple fourth frequencies, it means that the leaf node corresponds to Multiple downlink subcarriers.
  • one optical fiber is used for communication between the central node and the leaf nodes, and the frequencies of light used for uplink communication and downlink communication are different.
  • the execution subject in this embodiment of the present application may be a central node and/or a leaf node, the central node may be an OLT, and the leaf nodes may be an ONT or an ONU.
  • the central node includes a transmitter and a receiver.
  • the transmitter includes a digital signal processor (digital signal process, DSP), a digital-to-analog converter (DAC), a driver, and an optical modulation Devices and lasers
  • DSP is one of the processors.
  • DSP is used to generate signals in the digital domain.
  • Digital-to-analog converters are used to generate frequency-division multiplexed electrical signals on the electrical domain.
  • the driver is used for amplifying the frequency division multiplexing signal.
  • the optical modulator is used to modulate the frequency division multiplexing electrical signal onto the signal light emitted by the laser.
  • the driver is optional.
  • the receiver is a coherent receiver, see the receiver shown in Figure 6, and the receiver includes a mixer, a detector, an analog-to-digital converter (analog-to-digital converter, ADC) and a DSP.
  • the mixer is used to mix the received optical signal with local oscillator light.
  • the detector is used to convert the mixed optical signal into an electrical signal.
  • ADCs are used to convert electrical signals into signals in the digital domain.
  • DSP is used to obtain data from signals on the digital domain.
  • the leaf nodes also include transmitters and receivers, the transmitters are similar to the transmitters of the central node, and the receivers are similar to the receivers of the central node, which will not be repeated here.
  • the foregoing transmitter and receiver are only examples, and this embodiment of the present application does not limit the specific structures of the transmitter and receiver.
  • the DSP of the transmitter and receiver is the same DSP.
  • the central node and the leaf nodes also include memory
  • the memory is used to store data required in optical communication, for example, the memory of the central node is used to store the center frequency of the downlink subcarrier corresponding to each leaf node, etc., the leaf node
  • the memory is used to store the coding power ratio on the uplink sub-carrier and the like.
  • step 701 the processing flow of communication between the central node and the leaf node in the flow of optical communication, refer to step 701 to step 703 in the flow of optical communication shown in FIG. 7 .
  • the solution is described by taking the center node as an OLT and the leaf nodes as an ONT as an example.
  • Step 701 the central node generates downlink frequency division multiplexing electrical signals corresponding to multiple downlink subcarriers based on the center frequency of the downlink subcarriers corresponding to each leaf node and the coding power ratio on the corresponding downlink subcarriers, and each leaf node The central node is accessed, and data of multiple leaf nodes is encoded on at least one of the multiple downlink subcarriers.
  • each downlink subcarrier does not overlap in the frequency domain.
  • Each leaf node can correspond to one or more downlink subcarriers. Data of one or more leaf nodes can be encoded on each downlink sub-carrier.
  • FIG. 8 shows a schematic diagram of multiple leaf nodes sharing downlink subcarriers.
  • leaf node 1 and leaf node 2 share downlink subcarrier 1 within the same time range (such as During the time period from t1 to t2, leaf node 1 and leaf node 2 use the downlink subcarrier 1 at the same time, and during the time period from t2 to t3, leaf node 1 and leaf node 2 use the downlink subcarrier 1 at the same time), and within the same time range, the leaf node 3 and leaf node 4 share downlink subcarrier 2, and leaf node 4 and leaf node 5 share downlink subcarrier 3 within the same time range.
  • the coding power ratio is used to indicate the ratio of the coding power used when coding the data of the leaf node on the downlink subcarrier to the total power, and the total power is the coding power corresponding to the downlink subcarrier. For example, when a leaf node occupies a single downlink subcarrier, the coding power used when encoding data on the downlink subcarrier is equal to the total power of the downlink subcarrier, and the coding power ratio is 1. When multiple leaf nodes occupy a downlink subcarrier In the case of a subcarrier, the sum of the coding power used when coding the data of multiple leaf nodes on the downlink subcarrier is equal to the total power of the downlink subcarrier, and the coding power ratios are all less than 1.
  • the encoding power used when encoding data on each downlink subcarrier may be the same or different.
  • the central node determines the leaf nodes that access the central node, that is, determines the leaf nodes registered on the central node, which means that the central node establishes connections with each leaf node.
  • the central node sends data to each leaf node
  • the central node obtains the downlink subcarrier corresponding to each leaf node, and obtains the coding power ratio of each leaf node on the corresponding downlink subcarrier.
  • each leaf node is all the leaf nodes that communicate with the central node, or each leaf node is a part of the leaf nodes that communicate with the central node.
  • This part of the leaf nodes may have data to receive, and this part of the leaf nodes may also be Since the downlink subcarriers are shared with other leaf nodes, the shared downlink subcarriers may be encoded with the service data of the multiple leaf nodes, and the shared downlink subcarriers may also be encoded with the service data of some leaf nodes, and other For the preset data corresponding to some leaf nodes, the purpose of encoding the preset data on the downlink sub-carriers is to enable the leaf nodes sharing the downlink sub-carriers to decode and obtain their own data.
  • the central node uses the center frequency of the downlink subcarrier corresponding to each leaf node and the coding power ratio on the corresponding downlink subcarrier to encode the data of each leaf node to the corresponding downlink subcarrier, and generates multiple downlink subcarriers corresponding to Downlink frequency division multiplexing electrical signal.
  • the central node can generate the downlink frequency division multiplexing electrical signal in the following manner: the central node uses the total power corresponding to each downlink subcarrier and the coding power ratio of each leaf node on the corresponding downlink subcarrier to convert each leaf The data of the node is coded onto the corresponding downlink subcarriers to generate a baseband signal corresponding to each downlink subcarrier. Then corresponding to each downlink subcarrier, the central node frequency-shifts the baseband signal corresponding to the downlink subcarrier to obtain the downlink subcarrier signal corresponding to the downlink subcarrier. The central node combines downlink sub-carrier signals corresponding to each downlink sub-carrier, and obtains a downlink frequency division multiplexing electrical signal based on the combined signal.
  • step 702 the central node modulates the downlink frequency division multiplexing electrical signal onto the signal light of the first frequency to obtain a downlink frequency division multiplexing optical signal.
  • the signal light of the first frequency is emitted by the laser included in the central node, and the signal light of the first frequency is light of a single frequency.
  • the central node after the central node generates the downlink frequency-division multiplexed electrical signal, it modulates the downlink frequency-division multiplexed electrical signal onto the signal light of the first frequency through an optical modulator to obtain a downlink frequency-division multiplexed optical signal.
  • step 701 and step 702 may be completed by a transmitter in the central node.
  • transmitters include DSPs, DACs, drivers, optical modulators, and lasers.
  • the DSP encodes the data corresponding to each leaf node to the corresponding downlink subcarrier, and generates a baseband signal corresponding to each downlink subcarrier in the data domain. Then the DSP performs frequency shift on the baseband signal in the digital domain, so that the frequency of each baseband signal is shifted to the corresponding subcarrier, and the downlink subcarrier signal corresponding to each downlink subcarrier is obtained. Then the DSP sums each downlink sub-carrier signal and sends it to the DAC.
  • the DAC converts the added downlink sub-carrier signals to obtain downlink frequency division multiplexed electrical signals.
  • the driver amplifies the downlink frequency division multiplexing electrical signal, and the optical modulator modulates the downlink frequency division multiplexing electrical signal onto the signal light of the first frequency to obtain the downlink frequency division multiplexing optical signal.
  • Step 703 the central node sends the downlink frequency division multiplexed optical signal.
  • the central node uses the ODN in the PON to send the downlink frequency division multiplexed optical signal to each leaf node connected to the central node.
  • step 901 the processing flow of the leaf node in the optical communication flow, referring to step 901 to step 903 in the flow shown in FIG. 9 .
  • the first leaf node receives a downlink frequency division multiplexed optical signal sent by a central node, and the downlink frequency division multiplexed optical signal is modulated on signal light of a first frequency.
  • the first leaf node is any leaf node that accesses the central node.
  • Step 902 the first leaf node obtains the downlink subcarrier electrical signal corresponding to the first leaf node through the downlink frequency division multiplexing optical signal, and the downlink subcarrier electrical signal is encoded data on the downlink subcarrier corresponding to the leaf node In the obtained signal, data of multiple leaf nodes is encoded on the downlink subcarrier.
  • the first leaf node when the first leaf node coherently receives the optical signal sent by the central node, the first leaf node sets the frequency of the local oscillator light as the center frequency of the corresponding downlink subcarrier.
  • the first leaf node uses the local oscillator to coherently receive the downlink frequency division multiplexed optical signal, and obtains the downlink subcarrier electrical signal corresponding to the first leaf node.
  • the first leaf node uses the receiver to obtain the downlink subcarrier electrical signal, and the processing process is as follows:
  • the mixer in the receiver mixes the downlink FDM optical signal with the local oscillator light of the fourth frequency, and converts it into an electrical signal after being detected by the detector.
  • the center frequency of the electrical signal is equal to the frequency of the local oscillator light .
  • the receiver uses an ADC to convert the electrical signal into a digital domain, and obtains the downlink sub-carrier electrical signal corresponding to the first leaf node through band-pass filtering or post-frequency shift filtering.
  • Step 903 the first leaf node decodes the downlink sub-carrier electrical signal based on a non-orthogonal decoding method to obtain the data of the first leaf node.
  • the non-orthogonal decoding method is based on multiple leaf nodes in the downlink sub-carrier
  • the coding power ratio on the carrier is determined.
  • the first leaf node obtains the first leaf node on the downlink subcarrier electrical signal based on a non-orthogonal decoding method. node's data. For example, the first leaf node first uses the signal with a large coding power ratio as a useful signal, and decodes other signals as interference, and then subtracts the decoded useful signal, and so on, until the signal of the first leaf node is decoded, from The data of the first leaf node is extracted from the signal. If only the data of the first leaf node is encoded on the downlink subcarrier corresponding to the first leaf node, the first leaf node directly decodes the downlink subcarrier electrical signal to obtain the data of the first leaf node.
  • the first leaf node decodes its own data in the following manner:
  • the downlink subcarrier corresponding to the first leaf node is encoded with data of two leaf nodes, the two leaf nodes include the first leaf node and the second leaf node, if the encoding power of the first leaf node is lower than that of the second leaf node Coding power, at the receiving location of the first leaf node, the signal-to-noise ratio of the second leaf node signal is greater than the signal-to-noise ratio of the first leaf node signal, and the first leaf node first decodes the downlink sub-carrier electrical signal to obtain the second leaf node Then the first leaf node subtracts the signal of the second leaf node from the downlink subcarrier electrical signal, finally decodes the signal of the first leaf node, and then obtains the data of the first leaf node.
  • the signal of the first leaf node is higher than the encoding power of the second leaf node, the signal of the first leaf node has already experienced a large link loss, the signal-to-noise ratio of the received signal is low, and the first leaf node in the overall signal
  • the signal power of leaf nodes accounts for a large proportion, so the signal-to-noise ratio of the signal of the first leaf node is higher than that of the signal of the second leaf node, and the downlink sub-carrier electrical signals are all the data of the first leaf node, therefore, it can
  • the signal of the first leaf node is obtained directly without sequential decoding, where "directly" means that the signal obtained by decoding for the first time belongs to the first leaf node.
  • the central node can realize downlink communication only by sending out signal light of a single frequency, which can reduce the number of lasers for signal light.
  • at least one downlink subcarrier among the multiple downlink subcarriers is encoded with data of multiple leaf nodes, so that data of multiple leaf nodes can be sent in parallel, improving data transmission efficiency.
  • spectrum occupation can be reduced and spectrum resources can be saved.
  • each leaf node corresponds to only one downlink subcarrier
  • the data corresponding to itself can also be received in a direct detection manner.
  • the central node uses the signal-to-noise ratio to determine the downlink subcarriers corresponding to each leaf node, and the processing flow is shown in steps 1001 to 1004 in Figure 10:
  • Step 1001 the central node obtains the SNR of each leaf node on the downlink sub-carriers that can be received.
  • the downlink subcarrier that can be received is the downlink subcarrier that can be received coherently, that is to say, the leaf node can provide the local oscillator light whose frequency is the center frequency of the downlink subcarrier.
  • the central node can use the distance between the central node and each leaf node to determine the signal-to-noise ratio of each leaf node on the downlink subcarriers that can be received. For example, for any leaf node, assuming that the leaf node has the same signal-to-noise ratio on each downlink subcarrier that can be received, the central node uses the preset correspondence between the distance and the signal-to-noise ratio to determine the leaf node in each SNR on downlink subcarriers.
  • the central node may obtain the signal-to-noise ratio reported by each leaf node.
  • the processing flow refer to the flow shown in FIG. 11 .
  • Step 1101 the central node broadcasts power test optical signals corresponding to the plurality of downlink subcarriers.
  • the power test optical signal is used to instruct the leaf node to report the optical power of the received optical signal of the downlink subcarrier.
  • the same encoding method is used to encode the same data on each downlink subcarrier.
  • the same data is used to instruct the leaf node to report the received power after receiving it.
  • the encoding method can be arbitrary.
  • the encoding method adopts four-phase Keying (quadrature phase shift keying, QPSK), etc.
  • the central node generates a downlink frequency division multiplexing electrical signal, modulates the downlink frequency division multiplexing electrical signal onto the signal light of the first frequency, and obtains a downlink frequency division multiplexing optical signal, that is, a power test corresponding to multiple downlink subcarriers light signal.
  • the encoding power used when encoding data on each downlink subcarrier may be the same or different.
  • Step 1102 the first leaf node receives power test optical signals corresponding to multiple downlink subcarriers broadcast by the central node.
  • Step 1103 the first leaf node measures and obtains received power corresponding to at least one downlink subcarrier among the plurality of downlink subcarriers.
  • the received power is the optical power of the optical signal corresponding to at least one downlink subcarrier.
  • the first leaf node sends out local oscillator light, and the frequency of the local oscillator light is the same as or close to the center frequency of at least one downlink sub-carrier, where the frequency of the local oscillator light sent by the first leaf node can be preset configuration.
  • the first leaf node coherently receives at least one downlink subcarrier, and obtains received power corresponding to the at least one downlink subcarrier.
  • Step 1104 the first leaf node sends the received power to the central node.
  • the first leaf node sends the corresponding relationship between the received power and the center frequency of the downlink subcarrier to the central node.
  • the first leaf node uses a preset subcarrier to send received power to the central node, and at this time, each leaf node may use a different uplink subcarrier.
  • Step 1105 the central node receives received power corresponding to at least one downlink subcarrier sent by the first leaf node.
  • Step 1106 the central node determines the signal-to-noise ratio of each leaf node on the downlink subcarriers that can be received based on the received received power.
  • the signal-to-noise ratio is equal to the ratio of the maximum power amplitude of the signal to the maximum power amplitude of the noise.
  • the signal-to-noise ratio refers to an optical signal-to-noise ratio.
  • the downlink subcarrier that the leaf node can receive is the downlink subcarrier that the leaf node can receive coherently, that is, the leaf node can send out the local oscillator light of the center frequency of the downlink subcarrier.
  • the central node broadcasts the optical power test signal, the coding power corresponding to each downlink subcarrier is the same, which means that the signal-to-noise ratio of the leaf nodes on each downlink subcarrier is the same.
  • the central node calculates the signal-to-noise ratio of the first leaf node on one of the downlink subcarriers, and can determine the signal-to-noise ratios on all downlink subcarriers.
  • the process of determining the signal-to-noise ratio is as follows: assuming that the received power of the first leaf node receiving the signal corresponding to the downlink subcarrier 1 is y, and the received power y is optical power, first convert the received power y into the frequencies of the downlink subcarrier 1 The power x, the power x is the power of the electrical signal.
  • 2 ) represents the expected value of x 2
  • P2 Indicates the decision value of x recovered by DSP, for example, if the value of the recovered signal is 0.9, which is closer to 1, the decision value is 1, express expectations.
  • the coded powers corresponding to the downlink subcarriers may not be completely the same.
  • the leaf nodes need to send the received power corresponding to each downlink subcarrier that can be received to the central node.
  • Step 1002 the central node determines the center frequency of the downlink subcarrier corresponding to each leaf node and the coding power ratio on the corresponding downlink subcarrier based on the signal-to-noise ratio of each leaf node on the downlink subcarrier that can be received, On the target downlink subcarrier, the coding power ratio corresponding to the first leaf node is lower than the coding power ratio corresponding to the second leaf node, and the signal-to-noise ratio corresponding to the first leaf node is higher than the signal-to-noise ratio corresponding to the second leaf node .
  • the central node after the central node obtains the signal-to-noise ratio of each leaf node on the downlink sub-carrier that can be received, it can use the signal-to-noise ratio to determine the center frequency and the frequency of the downlink sub-carrier corresponding to each leaf node.
  • the coding power ratio on the corresponding downlink subcarrier It should be noted that the downlink subcarriers allocated to each leaf node belong to the downlink subcarriers that each leaf node can receive.
  • step 1002 if some leaf nodes have been pre-configured with corresponding downlink subcarriers, these leaf nodes no longer need to use SNR to determine the center frequency of the corresponding downlink subcarriers. Of course, these leaf nodes do not need to report the received power. Therefore, the leaf nodes in the process shown in FIG. 11 are the leaf nodes that need to use the signal-to-noise ratio to determine the corresponding downlink subcarriers.
  • each downlink subcarrier corresponds to at most two leaf nodes, that is, each downlink subcarrier is used to encode data of at most two leaf nodes.
  • the processing process for the central node to determine the center frequency of the downlink subcarrier corresponding to each leaf node is:
  • the same downlink subcarrier is allocated to two leaf nodes whose signal-to-noise ratio difference is greater than or equal to the target threshold.
  • the target threshold can be preset and stored in the central node.
  • the target threshold is 10dB, etc.
  • the central node when the central node allocates downlink subcarriers to each leaf node, it allocates the same downlink subcarrier to two leaf nodes whose signal-to-noise ratio difference is greater than or equal to the target threshold, that is, for the same downlink subcarrier
  • the difference between the signal-to-noise ratios of the two leaf nodes on the downlink subcarrier is greater than or equal to the target threshold.
  • the first leaf node and the second leaf node share the target downlink subcarrier
  • the difference between the signal-to-noise ratio of the first leaf node on the target downlink subcarrier and the second leaf node on the target downlink subcarrier is greater than or equal to the target threshold .
  • the leaf node uses only one downlink subcarrier.
  • the central node determines the leaf nodes that can receive the downlink subcarrier, and calculates the leaf nodes whose signal-to-noise ratio difference on the downlink subcarrier is greater than or equal to the target threshold. Then comprehensively consider the number of downlink subcarriers required by each leaf node, and determine the downlink subcarriers allocated to each leaf node. For example, the amount of data sent to the first leaf node is relatively large, and 3 downlink subcarriers need to be used. The first leaf node can also share 6 downlink subcarriers with other leaf nodes, or share 4 downlink subcarriers and occupy them separately a downlink subcarrier.
  • the number of downlink subcarriers required by each leaf node may be pre-configured.
  • each leaf node corresponds to two downlink subcarriers.
  • the number of downlink subcarriers required by each leaf node can be determined according to the amount of data received by each leaf node. The more data received, the more the number of downlink subcarriers allocated, and the less the amount of data received , the smaller the number of allocated downlink subcarriers. It should be noted that the number of leaf nodes corresponding to each downlink subcarrier can be set according to actual needs.
  • the target number of leaf nodes Nodes can decode and obtain their own data. After encoding the target number of downlink subcarriers plus the data of a leaf node, these leaf nodes cannot correctly decode and obtain their own data.
  • the number of leaf nodes corresponding to the downlink subcarrier is at most the target number .
  • the signal-to-noise ratio of each leaf node on the corresponding downlink subcarrier uses the signal-to-noise ratio of each leaf node on the corresponding downlink subcarrier to determine the frequency of each leaf node on the corresponding downlink subcarrier
  • the encoding power ratio of For example, the first leaf node and the second leaf node share the target downlink subcarrier, and the signal-to-noise ratio of the first leaf node on the target downlink subcarrier is higher than that of the second leaf node on the target downlink subcarrier.
  • the coding power ratio of a leaf node on the target downlink subcarrier is equal to N/M
  • the coding power ratio of the second leaf node on the target downlink subcarrier is equal to (M-N)/M
  • N/M is less than (M-N)/M
  • the sum of N/M and (M-N)/M is equal to 1.
  • the embodiment of the present application does not specifically limit the values of M and N. In this way, when the total power of the target downlink subcarrier is P, the coding power used by the first leaf node is N*P/M, and the coding power used by the second leaf node is (M-N)*P/M.
  • the coding power ratio of the leaf node on the downlink subcarrier is 1.
  • the coding power ratio corresponding to each leaf node can be set according to actual needs, and the goal is to enable each leaf node to decode Get your own data.
  • the center frequency of the downlink subcarrier corresponding to multiple leaf nodes is lower than the center frequency of the downlink subcarrier corresponding to one leaf node.
  • the signal-to-noise ratio of the downlink subcarrier with low center frequency is relatively high, and the downlink subcarrier with low center frequency is shared by multiple leaf nodes. Even if multiple leaf nodes share the downlink subcarrier with low center frequency, the respective The data.
  • the signal-to-noise ratio of a downlink subcarrier with a high center frequency is relatively low, and the downlink subcarrier with a high center frequency is used to carry data of a single leaf node. In this manner, it is possible to ensure that the data of each leaf node can be decoded correctly.
  • Step 1003 the central node sends a first message to each leaf node, where the first message is used to indicate the center frequencies of the downlink subcarriers corresponding to each leaf node.
  • the central node broadcasts a first message, and the first message is used to indicate the center frequencies of the downlink subcarriers corresponding to the leaf nodes.
  • Each leaf node connected to the central node can receive the first message.
  • the central node encodes the first message on each downlink subcarrier so that the leaf nodes can receive the first message, and the message field of the first message includes the center frequencies of the downlink subcarriers respectively corresponding to the leaf nodes.
  • the first message when data of multiple leaf nodes is encoded on one downlink subcarrier, the first message is also used to indicate the decoding mode of each leaf node on the corresponding downlink subcarrier.
  • the message field of the first message also includes a decoding method, and the process of determining the decoding method is:
  • the decoding method of each leaf node on the corresponding downlink subcarrier is that each leaf node is in The method of decoding data on the corresponding downlink subcarrier.
  • the decoding methods of the multiple leaf nodes are all non-orthogonal decoding methods, but the specific decoding methods are different.
  • a leaf node with a low signal-to-noise ratio has a high coding power, which causes greater interference to other leaf nodes corresponding to the same downlink subcarrier.
  • Each leaf node can first decode the signal of the leaf node with the highest coding power, subtract the signal of the leaf node with the highest coding power from the signal of the entire downlink subcarrier, and then decode the signal with the second largest coding power, and so on By analogy, until the signals of all leaf nodes are separated. For each leaf node, the leaf node needs to know how many times the parsed signal belongs to itself, and it will be indicated in the decoding method.
  • the decoding method is an orthogonal decoding method, and each leaf node can directly decode to obtain its own signal.
  • Step 1004 the first leaf node receives a first message, and the first message is used to indicate the center frequency of the downlink subcarrier corresponding to each leaf node and the decoding mode on the corresponding downlink subcarrier.
  • the first leaf node acquires the center frequency of its corresponding downlink subcarrier in the first message, and adjusts the frequency of the local oscillator to be the same as the center frequency of the corresponding downlink subcarrier. In this way, the first leaf node can coherently receive the data sent by the central node. And the first leaf node stores the decoding mode on the corresponding downlink subcarrier.
  • the process shown in FIG. 10 may be executed to allocate downlink subcarriers to each leaf node.
  • the process shown in FIG. 10 is periodically executed, so that the downlink subcarriers allocated to the leaf nodes can be reasonably adjusted.
  • the central node newly accesses one or more leaf nodes, execute the process shown in FIG. 10 .
  • the leaf node reports that it has not received the data sent by the central node for a long time, the process shown in FIG. 10 is executed.
  • the leaf node reports that it has not received the data sent by the central node for a long time
  • the central node may also allocate uplink subcarriers to each leaf node, and the processing method is as follows:
  • the central node obtains the signal-to-noise ratio of each leaf node on the uplink subcarrier that can be sent; based on the signal-to-noise ratio of each leaf node on the uplink subcarrier that can be sent, determine the uplink subcarrier corresponding to each leaf node and the coding power ratio on the corresponding uplink subcarrier.
  • the coding power ratio corresponding to the third leaf node is lower than the coding power ratio corresponding to the fourth leaf node.
  • the third leaf node corresponds to The signal-to-noise ratio of the fourth leaf node is higher than the signal-to-noise ratio corresponding to the fourth leaf node; a second message is sent to each leaf node, and the second message is used to indicate the center frequency of the uplink subcarrier corresponding to each leaf node and in the corresponding Coding power ratio on uplink subcarriers.
  • the central node may obtain the signal-to-noise ratio of each leaf node on the uplink subcarriers that can be sent.
  • the central node allocates uplink subcarriers to each leaf node, it allocates the same uplink subcarrier to two leaf nodes whose signal-to-noise ratio difference is greater than or equal to the target threshold, that is, for two leaf nodes corresponding to the same uplink subcarrier node, the difference between the signal-to-noise ratios of the two leaf nodes on the uplink subcarrier is greater than or equal to the target threshold.
  • the central node determines the center frequency of the uplink subcarrier corresponding to each leaf node and the coding power ratio on the corresponding uplink subcarrier, it sends a second message to each leaf node, and the message field of the second message includes each leaf node.
  • each leaf node obtains the second message, it analyzes and obtains the center frequency of its corresponding uplink subcarrier and the coding power ratio on the corresponding uplink subcarrier.
  • the leaf node when there is no uplink subcarrier whose signal-to-noise ratio difference with other leaf nodes is greater than or equal to the target threshold, the leaf node uses only one uplink subcarrier.
  • the manner in which the central node obtains the signal-to-noise ratio of each leaf node on the uplink subcarriers that can be sent is:
  • the central node obtains the signal-to-noise ratio of each leaf node on each downlink subcarrier. Since the central node sends data to the leaf node, and the leaf node sends data to the central node using the same optical fiber, therefore, the signal-to-noise ratio on each downlink subcarrier can be used to determine the uplink subcarrier that each leaf node can send SNR.
  • the signal-to-noise ratio on the first downlink subcarrier is determined as the signal-to-noise ratio of the uplink subcarrier whose center frequency is this frequency.
  • the signal-to-noise ratio of the leaf node on each uplink sub-carrier is the same, which is the determined signal-to-noise ratio. Based on this method, the signal-to-noise ratio of each leaf node on the uplink sub-carriers that can be sent can be determined.
  • the uplink subcarriers and the downlink subcarriers have the same bandwidth.
  • the coding power of each uplink subcarrier is the same.
  • the central node determines the leaf nodes capable of sending the uplink subcarrier, and calculates the leaf nodes whose signal-to-noise ratio difference on the uplink subcarrier is greater than or equal to the target threshold. Then comprehensively consider the number of uplink subcarriers required by each leaf node, and determine the uplink subcarriers allocated to each leaf node.
  • the number of uplink subcarriers required by each leaf node may be preconfigured, for example, each leaf node corresponds to two uplink subcarriers. Or the number of uplink subcarriers required by each leaf node can be determined according to the amount of data sent by each leaf node. The more data sent, the more the number of uplink subcarriers allocated, and the less data sent , the smaller the number of allocated uplink subcarriers. It should be noted that the number of leaf nodes corresponding to each uplink subcarrier can be set according to actual needs.
  • the central node can decode Obtain the data of the target number of leaf nodes. After encoding the data of the target number plus one leaf node on the uplink subcarrier, the central node cannot decode and obtain the data of the target number of leaf nodes.
  • the maximum number of leaf nodes corresponding to the uplink subcarrier is number of targets.
  • the coding power ratio of each leaf node on the corresponding uplink subcarrier is determined.
  • the third leaf node and the fourth leaf node share the target uplink subcarrier, and the signal-to-noise ratio of the third leaf node on the target uplink subcarrier is higher than that of the fourth leaf node on the target uplink subcarrier.
  • the coding power ratio of the three leaf nodes on the target uplink subcarrier is equal to N1/M1
  • the coding power ratio of the fourth leaf node on the target uplink subcarrier is equal to (M1-N1)/M1
  • N1/M1 is less than (M1-N1) /M1
  • the sum of N1/M1 and (M1-N1)/M1 is equal to 1.
  • the embodiment of the present application does not specifically limit the values of M1 and N1. In this way, when the total power of the target uplink subcarrier is P1, the coding power used by the third leaf node is N1*P1/M1, and the coding power used by the fourth leaf node is (M1-N1)*P1/M1.
  • the coding power ratio of the leaf node on the uplink subcarrier is 1.
  • the center frequency of the uplink subcarrier corresponding to multiple leaf nodes is lower than the center frequency of the uplink subcarrier corresponding to one leaf node.
  • the signal-to-noise ratio of the uplink subcarrier with a low center frequency is relatively high, and the uplink subcarrier with a low center frequency is used for sharing by multiple leaf nodes. Even if multiple leaf nodes share, respective data can be parsed out.
  • the signal-to-noise ratio of the uplink subcarrier with high center frequency is relatively low, and the uplink subcarrier with high center frequency is used to carry the data of a single leaf node.
  • center frequency of the downlink subcarrier, the center frequency of the uplink subcarrier and the decoding method corresponding to each leaf node can be set in the same message and sent together, or sent separately.
  • the first leaf node before the first leaf node sends data to the central node, the first leaf node receives the second message, and when sending data, the first leaf node bases the first leaf node on the target uplink subcarrier Encoding the power ratio to generate an uplink electrical signal corresponding to the target uplink subcarrier, the target uplink subcarrier being the uplink subcarrier corresponding to the first leaf node; modulating the uplink electrical signal onto the signal light of the second frequency to obtain the uplink light signal, the second frequency is the same as the center frequency of the target uplink subcarrier; the first leaf node sends the uplink optical signal.
  • the first leaf node receives the second message, and adjusts the frequency of the transmitted signal light to the center frequency according to the center frequency of the uplink subcarrier corresponding to the first leaf node indicated in the second message. And the first leaf node stores the coding power ratio on the corresponding uplink subcarrier.
  • the DSP in the transmitter uses the coding power ratio to generate a baseband signal corresponding to the target uplink subcarrier. Then the DSP performs frequency shift processing on the baseband signal, so that the frequency of the baseband signal is shifted to the corresponding target uplink subcarrier, and the uplink subcarrier signal corresponding to the target uplink subcarrier is obtained, and the DSP sends the uplink subcarrier signal to the DAC .
  • the DAC converts the uplink sub-carrier signal to obtain an uplink electrical signal, and the driver amplifies the uplink electrical signal.
  • the optical modulator modulates the uplink electrical signal onto the signal light of the second frequency to obtain an uplink optical signal.
  • the second frequency is the same as the center frequency of the target uplink subcarrier, that is, the frequency of the signal light is the same as the center frequency of the target uplink subcarrier.
  • the central node can receive the uplink data sent by the leaf nodes, and the processing process is as follows:
  • the central node receives the uplink frequency division multiplexing optical signal; in the uplink frequency division multiplexing optical signal, the data of each leaf node is obtained through coherent reception.
  • the uplink optical signals sent by each leaf node are aggregated into one optical fiber through the ODN in the PON, and sent to the central node.
  • the optical signal received by the central node is an uplink frequency division multiplexing optical signal.
  • the central node coherently receives the data of each leaf node in the uplink frequency division multiplexing optical signal. For example, the central node mixes the local oscillator light of the third frequency with the uplink frequency division multiplexing optical signal, and obtains the electrical signal centered on the third frequency after passing through the detector. Then the electrical signal is frequency-shifted to the center frequency of each uplink sub-carrier, and then the uplink electrical signal corresponding to each leaf node is obtained through band-pass filtering processing, and then the uplink data corresponding to each leaf node is obtained.
  • the local oscillator of the third frequency is the center frequency of all uplink subcarriers.
  • a single uplink subcarrier corresponds to multiple leaf nodes
  • the central node can use the leaf node identifiers to distinguish the data of each leaf node.
  • the coding power is controlled so that different leaf nodes use the same downlink subcarrier or the same uplink subcarrier, so as to realize non-orthogonal coding of multiple leaf nodes.
  • a non-orthogonal encoding method based on sparse code multiple access (SCMA) may also be used, so that the data of multiple leaf nodes share uplink subcarriers or downlink subcarriers. For example, every 6 leaf nodes share 4 downlink subcarriers, each subcarrier encodes data of two leaf nodes, and on the same downlink subcarrier, data of two leaf nodes is encoded using different encoding methods.
  • SCMA sparse code multiple access
  • PON is based on frequency division multiplexing instead of time division multiplexing, and the data of multiple leaf nodes can be sent in parallel at the same time, which can relatively reduce the delay of data transmission. In this way, data transmission delays can be reduced in scenarios that require high transmission delays such as industrial parks and traffic.
  • guard intervals need to be reserved between optical carriers of different leaf nodes.
  • the data of multiple leaf nodes is encoded onto one or more subcarriers at the same time, which can save spectrum resources and improve the overall bandwidth of the system. In this way, spectrum resources can be saved in future Internet of Things (IOT) scenarios and scenarios with a large number of concurrently connected users.
  • IOT Internet of Things
  • FIG. 12 is a structural diagram of an optical communication device provided by an embodiment of the present application.
  • the device can be implemented as part or all of the device through software, hardware or a combination of the two, and the device is applied to the central node in the PON.
  • the device provided in the embodiment of the present application can realize the process described in FIG. 7 of the embodiment of the present application, and the device includes: a generating module 1210, a modulating module 1220, and a sending module 1230, wherein:
  • the generating module 1210 is configured to generate downlink frequency division multiplexing electrical signals corresponding to multiple downlink subcarriers based on the center frequency of the downlink subcarriers corresponding to each leaf node and the coding power ratio on the corresponding downlink subcarriers, each The leaf node accesses the central node, and at least one of the multiple downlink subcarriers is encoded with the data of multiple leaf nodes, which can be used to realize the generation function of step 701 and execute the implicit step;
  • the modulation module 1220 is configured to modulate the downlink frequency division multiplexing electrical signal onto the signal light of the first frequency to obtain a downlink frequency division multiplexing optical signal, which can be specifically used to realize the modulation function of step 702 and perform step 702 including the implicit steps of
  • the sending module 1230 is configured to send the downlink frequency division multiplexed optical signal, and may specifically be used to realize the sending function of step 703 and perform the implicit steps included in step 703 .
  • the device further includes: an obtaining module, configured to obtain the downlink frequency division multiplexing signals that each leaf node can receive before generating the downlink frequency division multiplexing electrical signals corresponding to the multiple downlink subcarriers. Signal-to-noise ratio on subcarriers;
  • the coding power ratio corresponding to the first leaf node is lower than the coding power ratio corresponding to the second leaf node, and the signal-to-noise ratio corresponding to the first leaf node is higher than the signal-to-noise ratio corresponding to the second leaf node;
  • the sending module 1230 is further configured to send a first message to each of the leaf nodes, where the first message is used to indicate the center frequencies of the downlink subcarriers corresponding to each of the leaf nodes.
  • the acquisition module acquires the signal-to-noise ratio of each leaf node on the downlink subcarriers that can be received, including:
  • the acquisition module broadcasts the power test optical signal corresponding to the plurality of downlink subcarriers; the acquisition module receives the received power corresponding to at least one downlink subcarrier sent by each leaf node; Power, to determine the signal-to-noise ratio of each leaf node on the downlink sub-carriers that can be received.
  • the first message is also used to indicate the decoding mode of each leaf node on the corresponding downlink subcarrier
  • the acquisition module is further configured to determine the leaf nodes based on the downlink subcarriers corresponding to the leaf nodes and the coding power ratio on the corresponding downlink subcarriers before sending the first message to the leaf nodes.
  • each downlink subcarrier corresponds to at most two leaf nodes
  • a difference between the signal-to-noise ratios of the first leaf node and the second leaf node on the target downlink subcarrier is greater than or equal to a target threshold.
  • the center frequency of the downlink subcarrier corresponding to multiple leaf nodes is lower than the center frequency of the downlink subcarrier corresponding to one leaf node.
  • the device further includes: an acquisition module, configured to acquire the signal-to-noise ratio of each leaf node on the uplink subcarriers that can be sent;
  • the coding power ratio corresponding to the third leaf node is lower than the coding power ratio corresponding to the fourth leaf node, and the signal-to-noise ratio corresponding to the third leaf node is higher than the signal-to-noise ratio corresponding to the fourth leaf node;
  • the sending module 1230 is further configured to send a second message to each leaf node, where the second message is used to indicate the center frequency of the uplink subcarrier corresponding to each leaf node and the frequency on the corresponding uplink subcarrier. Encoding power ratio.
  • the device further includes:
  • the receiving module is configured to receive an uplink frequency division multiplexing optical signal; in the uplink frequency division multiplexing optical signal, obtain the data of each leaf node through coherent reception.
  • the data of multiple leaf nodes encoded on each downlink subcarrier in the at least one downlink subcarrier is non-orthogonal encoding based on SCMA.
  • the generation module 1210 corresponds to the DSP and DAC of the central node, for example, the DSP encodes the data corresponding to each leaf node to the corresponding downlink subcarrier, and obtains the downlink subcarrier corresponding to each downlink subcarrier For the carrier signal, the DSP adds the downlink subcarrier signals corresponding to each downlink subcarrier and sends them to the DAC, and the DAC converts the added signals to obtain the downlink frequency division multiplexing electrical signal.
  • the modulation module 1220 and the sending module 1230 correspond to the driver and the optical modulator described above, for example, the driver amplifies the downlink frequency division multiplexing electrical signal (it is an optional process), and the optical modulator amplifies the downlink frequency division multiplexing electrical signal The electrical signal is modulated onto the signal light of the first frequency to obtain a downlink frequency division multiplexed optical signal, and the downlink frequency division multiplexed optical signal is sent.
  • the acquisition module corresponds to the transmitter and receiver of the central node.
  • the transmitter sends out an optical power test signal, and the receiver receives the received power sent by the leaf node.
  • the transmitter can also determine the signal-to-noise ratio, etc., and send the first First message and second message etc.
  • the receiving module corresponds to the receiver of the central node.
  • the mixer and detector in the receiver coherently receive the optical signal, convert the optical signal into an electrical signal, and the DSP decodes the electrical signal to obtain the data of the leaf node.
  • FIG. 13 is a structural diagram of an optical communication device provided by an embodiment of the present application.
  • the device can be implemented as part or all of the device through software, hardware or a combination of the two, and the device is applied to the first leaf node in the PON.
  • the device provided in the embodiment of the present application can realize the process described in FIG. 9 of the embodiment of the present application, and the device includes: a receiving module 1310 and a decoding module 1320, wherein:
  • the receiving module 1310 is configured to receive the downlink frequency division multiplexing optical signal sent by the central node, the downlink frequency division multiplexing optical signal is modulated on the signal light of the first frequency, and can be specifically used to realize the receiving function of step 901 and execute The implicit steps involved in step 901;
  • the decoding module 1320 is configured to obtain the downlink subcarrier electrical signal corresponding to the first leaf node through the downlink frequency division multiplexing optical signal, and the downlink subcarrier electrical signal is the downlink subcarrier corresponding to the first leaf node A signal obtained by encoding data on a subcarrier, the downlink subcarrier is encoded with data of multiple leaf nodes; based on a non-orthogonal decoding method, decoding the downlink subcarrier electrical signal to obtain the first leaf node data, the non-orthogonal decoding method is determined based on the coding power ratio of the plurality of leaf nodes on the downlink subcarriers, and can be used specifically to implement the decoding functions of steps 902 and 903 and perform steps 902 and 903 Step 903 contains implicit steps.
  • the receiving module 1310 is further configured to receive a first message before receiving the downlink frequency division multiplexed optical signal, and the first message is used to indicate the downlink child node corresponding to each leaf node.
  • the center frequency and decoding mode of the carrier, and the leaf nodes access the center node.
  • the plurality of leaf nodes include a first leaf node and a second leaf node
  • the decoding module 1320 decodes the downlink subcarrier electrical signal to obtain the data of the first leaf node based on a non-orthogonal decoding method, including:
  • the decoding module 1320 decodes the downlink subcarrier electrical signal to obtain the signal of the second leaf node, and then Subtracting the signal of the second leaf node from the downlink subcarrier electrical signal to obtain the signal of the first leaf node; if the coding power ratio of the first leaf node is higher than the coding power ratio of the second leaf node power ratio, the decoding module 1320 directly decodes the downlink subcarrier electrical signal to obtain the signal of the first leaf node;
  • the decoding module 1320 extracts the data of the first leaf node from the signal of the first leaf node.
  • the receiving module 1310 is further configured to:
  • the second message is used to indicate the center frequency of the uplink subcarrier corresponding to each leaf node and the coding power ratio on the corresponding uplink subcarrier, and each leaf node accesses the central node;
  • the device further includes: a sending module, configured to generate an uplink electrical signal corresponding to the target uplink subcarrier based on the encoding power ratio corresponding to the target uplink subcarrier of the first leaf node, and the target uplink subcarrier is the target uplink subcarrier The uplink subcarrier corresponding to the first leaf node;
  • the receiving module 1310 is further configured to:
  • the device further includes: a sending module, configured to measure and obtain received power corresponding to at least one downlink sub-carrier among the plurality of downlink sub-carriers; and send the received power to the central node.
  • a sending module configured to measure and obtain received power corresponding to at least one downlink sub-carrier among the plurality of downlink sub-carriers; and send the received power to the central node.
  • the receiving module 1310 corresponds to the above-mentioned mixer.
  • the mixer mixes the received optical signal with the local oscillator light to realize the reception of the downlink frequency division multiplexed optical signal.
  • the decoding module 1320 corresponds to the detector, ADC and DSP mentioned above, for example, the detector converts the mixed signal into a downlink frequency division multiplexing electrical signal, and the ADC converts the downlink frequency division multiplexing electrical signal into a signal in the digital domain , the DSP obtains the downlink sub-carrier electrical signal corresponding to the first leaf node from the signal, and decodes the downlink sub-carrier electrical signal to obtain the data of the first leaf node.
  • the sending module corresponds to the transmitter in the leaf node, for example, the DSP in the transmitter encodes its own data to the corresponding downlink sub-carrier to obtain the downlink sub-carrier signal, and the DSP sends the downlink sub-carrier signal to the DAC, The DAC converts the downlink sub-carrier signal to obtain an uplink electrical signal, and the optical modulator modulates the uplink electrical signal onto the signal light of the second frequency to obtain an uplink optical signal and transmits the signal light of the second frequency.
  • the disclosed system architecture, device and method can be implemented in other ways.
  • the device embodiments described above are only illustrative.
  • the division of the modules is only a logical function division. In actual implementation, there may be other division methods.
  • multiple modules or components can be combined or can be Integrate into another system, or some features may be ignored, or not implemented.
  • the mutual coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices or modules, and may also be electrical, mechanical or other forms of connection.
  • the modules described as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical modules, that is, they may be located in one place, or may be distributed to multiple network modules. Part or all of the modules can be selected according to actual needs to achieve the purpose of the solution of the embodiment of the present application.
  • each module in each embodiment of the present application may be integrated into one processing module, each module may exist separately physically, or two or more modules may be integrated into one module.
  • the above-mentioned integrated modules can be implemented in the form of hardware or in the form of software modules.
  • the integrated module is realized in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium.
  • the technical solution of the present application is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of software products, and the computer software products are stored in a storage medium
  • several instructions are included to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods in the various embodiments of the present application.
  • the aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (read-only memory, ROM), random access memory (random access memory, RAM), magnetic disk or optical disc and other media that can store program codes. .
  • first and second are used to distinguish the same or similar items with basically the same function and function. It should be understood that there is no logic or sequence between “first” and “second” Dependencies on the above, and there are no restrictions on the number and execution order. It should also be understood that although the following description uses the terms first, second, etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, a first message could be termed a second message, and, similarly, a second message could be termed a first message, without departing from the scope of the various examples. Both the first message and the second message may be messages, and in some cases, separate and distinct messages.

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Abstract

本申请提供了一种光通信的方法、装置和***，属于PON通信技术领域。该方法包括：中心节点基于各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，生成多个下行子载波对应的下行频分复用电信号，各叶子节点接入中心节点，多个下行子载波中至少一个下行子载波上编码有多个叶子节点的数据。将下行频分复用电信号调制到第一频率的信号光上，获得下行频分复用光信号，发送下行频分复用光信号。采用本申请，中心节点提供一个频率的信号光，使得中心节点需要一个信号光的激光器，简化中心节点的处理过程。而且至少一个下行子载波上编码有多个叶子节点的数据，使得多个叶子节点的数据能够并行发送。

Description

光通信的方法、装置和***
本申请要求于2021年12月31日提交中国国家知识产权局、申请号202111664021.X、申请名称为“光通信的方法、装置和***”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及光通信技术领域，特别涉及一种光通信的方法、装置和***。
背景技术
光传输***有多种网络架构，常见的网络架构包括点到多点(point to multi-point，PTMP)网络架构。点到多点网络架构是指单个设备与多个设备之间建立的传输连接。点到多点网络架构目前广泛应用于无源光网络(passive optical network，PON)中。在PON中，光线路终端(optical line terminal，OLT)作为中心节点，光网络终端(optical network terminal，ONT)或者光网络单元(optical network unit，ONU)作为叶子节点。
相关技术中，OLT与ONT之间传输数据采用波分复用技术。例如，OLT能够发出多个频率的光，每个频率的光对应一个ONT，作为ONT的光载波。OLT为每个ONT调制不同频率的光载波信号，OLT连接的波分复用器将多个频率的光载波信号合并，通过光纤传输至ONT侧。OLT连接的解复用器将各个频率的光载波信号进行分离，分别传输至各个ONT。
相关技术中，OLT需要为每个ONT调制不同频率的光载波信号，PON中的ONT数量一般比较多，OLT需要发出多种不同频率的光，进而需要多个激光器，会导致OLT的处理过程比较复杂。
发明内容
本申请提供了一种光通信的方法、装置和***，能够简化OLT的处理过程。
第一方面，本申请提供了一种光通信的方法，由PON中的中心节点执行，该方法包括：
基于各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，生成多个下行子载波对应的下行频分复用电信号，该各叶子节点接入该中心节点，该多个下行子载波中至少一个下行子载波上编码有多个叶子节点的数据；将该下行频分复用电信号调制到第一频率的信号光上，获得下行频分复用光信号；发送该下行频分复用光信号。
本申请所示的方案，各叶子节点为接入中心节点的叶子节点。下行子载波为PON中用于下行通信的子载波。中心节点将多个叶子节点的数据，编码为多个下行子载波对应的下行频分复用电信号，通过第一频率的信号光，发送该下行频分复用电信号，并且在多个下行子载波中，至少一个下行子载波上编码有多个叶子节点的数据。这样，中心节点仅提供单频率的信号光，而不需要使用多个激光器，简化中心节点的处理。而且多个叶子节点还可共用一个 下行子载波，可以节约频谱资源。
在一种可能的实现方式中，在生成多个下行子载波对应的下行频分复用电信号之前，还包括：获取该各叶子节点在所能接收的下行子载波上的信噪比；基于该各叶子节点在所能接收的下行子载波上的信噪比，确定该各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，在目标下行子载波上，第一叶子节点对应的编码功率比例低于第二叶子节点对应的编码功率比例，该第一叶子节点对应的信噪比高于该第二叶子节点对应的信噪比；向该各叶子节点发送第一消息，该第一消息用于指示该各叶子节点分别对应的下行子载波的中心频率。
本申请所示的方案，中心节点可以使用各叶子节点在所能接收的下行子载波上的信噪比，确定出各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，对于使用同一个下行子载波的多个叶子节点，使得高信噪比的叶子节点对应的编码功率低于低信噪比的叶子节点对应的编码功率，使得使用同一个下行子载波的多个叶子节点更容易解码获得自身的数据。
在一种可能的实现方式中，该获取该各叶子节点在所能接收的下行子载波上的信噪比，包括：广播该多个下行子载波对应的功率测试光信号；接收该各叶子节点发送的至少一个下行子载波对应的接收功率；基于接收到的接收功率，确定该各叶子节点在所能接收的下行子载波上的信噪比。
本申请所示的方案，中心节点可以使用各叶子节点对光信号的接收功率，获得各叶子节点在所能接收的下行子载波上的信噪比。
在一种可能的实现方式中，该第一消息还用于指示该各叶子节点在对应的下行子载波上的解码方式；该向该各叶子节点发送第一消息之前，还包括：基于该各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，确定该各叶子节点在对应的下行子载波的解码方式，该解码方式为该各叶子节点在对应的下行子载波上解码数据的方式。
本申请所示的方案，中心节点还可以确定出各叶子节点在对应的下行子载波的解码方式，并且通知给叶子节点，使得叶子节点能够准确解码获得自身的数据。
在一种可能的实现方式中，每个下行子载波最多对应两个叶子节点；该第一叶子节点和该第二叶子节点在该目标下行子载波上的信噪比的差值大于或等于目标阈值。这样，使用同一个下行子载波的叶子节点在该下行子载波上的信噪比差值比较大，使得使用同一个下行子载波的叶子节点更容易解码获得自身的数据。
在一种可能的实现方式中，在该多个下行子载波中，对应有多个叶子节点的下行子载波的中心频率低于对应有一个叶子节点的下行子载波的中心频率。这样，由于中心频率高的下行子载波对应的信噪比一般低于中心频率低的下行子载波对应的信噪比，所以中心频率低的下行子载波更适合于多个叶子节点共享，使得使用同一个下行子载波的叶子节点更容易解码获得自身的数据。
在一种可能的实现方式中，该方法还包括：获取该各叶子节点在所能发送的上行子载波上的信噪比；基于该各叶子节点在所能发送的上行子载波上的信噪比，确定该各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例，在目标上行子载波上，第三叶子节点对应的编码功率比例低于第四叶子节点对应的编码功率比例，该第三叶子节点对应的信噪比高于该第四叶子节点对应的信噪比；向该各叶子节点发送第二消息，该第二消 息用于指示该各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例。
本申请所示的方案，中心节点可以使用各叶子节点在所能接收的上行子载波上的信噪比，确定出各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例，对于使用同一个上行子载波的多个叶子节点，使得高信噪比的叶子节点对应的编码功率低于低信噪比的叶子节点对应的编码功率，使得中心节点能够区分开同一个上行子载波对应的多个叶子节点的数据。
在一种可能的实现方式中，该方法还包括：接收上行频分复用光信号；在该上行频分复用光信号中，通过相干接收获得该各叶子节点的数据。这样，中心节点可以将各个叶子节点的数据区分开。
在一种可能的实现方式中，该至少一个下行子载波中每个下行子载波上基于稀疏码分复用(sparse code multiple access，SCMA)的非正交编码方式编码多个叶子节点的数据。
第二方面，本申请提供了一种光通信的方法，由PON中的第一叶子节点执行，该方法包括：接收中心节点发送的下行频分复用光信号，该下行频分复用光信号调制在第一频率的信号光上；通过该下行频分复用光信号，获得该第一叶子节点对应的下行子载波电信号，该下行子载波电信号为在该第一叶子节点对应的下行子载波上编码数据获得的信号，该下行子载波上编码有多个叶子节点的数据；基于非正交的解码方式，在该下行子载波电信号中解码获得该第一叶子节点的数据，该非正交的解码方式是基于该多个叶子节点在该下行子载波上的编码功率比例确定的。
本申请所示的方案，第一叶子节点为PON中的任一叶子节点，在第一叶子节点对应的下行子载波上对应有多个叶子节点时，第一叶子节点可以先获得该下行子载波对应的下行子载波电信号，然后使用非正交的解码方式从该下行子载波电信号上，解码获得自身的数据，非正交的解码方式是基于该多个叶子节点在该下行子载波上的编码功率比例确定的。这样，在中心节点使用单频率的信号光的情况下，叶子节点也能接收到自身的数据，能够简化中心节点的处理过程。另外多个叶子节点可以共用下行子载波，也可以节约频谱资源。
在一种可能的实现方式中，该接收下行频分复用光信号之前，还包括：接收第一消息，该第一消息用于指示各叶子节点分别对应的下行子载波和解码方式，该各叶子节点接入该中心节点。
在一种可能的实现方式中，该多个叶子节点包括第一叶子节点和第二叶子节点；该基于非正交的解码方式，在该下行子载波电信号中解码获得第一叶子节点的数据，包括：若第一叶子节点的编码功率比例低于第二叶子节点的编码功率比例，则从该下行子载波电信号中解码获得第二叶子节点的信号，在该下行子载波电信号中减去第二叶子节点的信号，获得第一叶子节点的信号；若第一叶子节点的编码功率比例高于第二叶子节点的编码功率比例，则从该下行子载波电信号中直接解码获得第一叶子节点的信号；从第一叶子节点的信号上提取得到第一叶子节点的数据。
本申请所示的方案，在第一叶子节点对应的下行子载波上还编码有第二叶子节点的数据时，由于第一叶子节点和第二叶子节点使用的编码功率比例相同，所以可以基于编码功率比例不同，从下行子载波电信号上解码出自身的数据。
在一种可能的实现方式中，该方法还包括：接收第二消息，该第二消息用于指示各叶子 节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例，该各叶子节点接入该中心节点；基于第一叶子节点在目标上行子载波对应的编码功率比例，生成目标上行子载波对应的上行电信号，目标上行子载波为所述第一叶子节点对应的上行子载波；将该上行电信号调制到第二频率的信号光上，获得上行光信号，该第二频率与该目标上行子载波的中心频率相同；发送该上行光信号。
本申请所示的方案，第一叶子节点可以使用中心节点配置的上行子载波和编码功率比例，上行发送数据。
在一种可能的实现方式中，该接收下行频分复用光信号之前，还包括：接收该中心节点广播的多个下行子载波对应的功率测试光信号；测量获得该多个下行子载波中至少一个下行子载波对应的接收功率；向该中心节点发送该接收功率。
第三方面，本申请提供了一种光通信的装置，该装置具有实现上述第一方面或第一方面任一种可选方式的功能。该装置包括至少一个模块，至少一个模块用于实现上述第一方面或第一方面任一种可选方式所提供的光通信方法。
第四方面，本申请提供了一种光通信的装置，该装置具有实现上述第二方面或第二方面任一种可选方式的功能。该装置包括至少一个模块，至少一个模块用于实现上述第二方面或第二方面任一种可选方式所提供的光通信方法。
第五方面，本申请提供了一种中心节点，该中心节点包括处理器和光调制器，所述处理器用于对上述第一方面或第一方面任一种可选方式中的电信号进行处理，例如，基于信噪比，确定各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例。所述光调制器用于将所述电信号调制到信号光上。
第六方面，本申请提供了一种叶子节点，该叶子节点包括处理器和探测器，所述处理器对上述第二方面或第二方面任一种可选方式中的电信号进行处理，例如，从电信号中获得叶子节点的数据，所述探测器用于接收光信号，将光信号转换为电信号。
第七方面，本申请提供了一种计算机可读存储介质，该存储介质中存储有至少一条计算机指令，该计算机指令由处理器读取以使中心节点对上述第一方面或第一方面任一种可选方式中的电信号进行处理。
第八方面，本申请提供了一种计算机可读存储介质，该存储介质中存储有至少一条计算机指令，该计算机指令由处理器读取以使叶子节点对上述第二方面或第二方面任一种可选方式中的电信号进行处理。
第九方面，本申请提供了一种光通信的***，所述***包括中心节点和多个叶子节点，该中心节点用于实现上述第一方面或第一方面任一种可选方式所提供的光通信方法，每个叶子节点用于实现上述第二方面或第二方面任一种可选方式所提供的光通信方法。
附图说明
图1是本申请一个示例性实施例提供的PON的逻辑架构示意图；
图2是本申请一个示例性实施例提供的传统PON的架构示意图；
图3是本申请一个示例性实施例提供的上行通信的架构示意图；
图4是本申请一个示例性实施例提供的下行通信的架构示意图；
图5是本申请一个示例性实施例提供的发射机的架构示意图；
图6是本申请一个示例性实施例提供的接收机的架构示意图；
图7是本申请一个示例性实施例提供的光通信的方法的流程示意图；
图8是本申请一个示例性实施例提供的频谱和时间复用的示意图；
图9是本申请一个示例性实施例提供的光通信的方法的流程示意图；
图10是本申请一个示例性实施例提供的确定叶子节点对应的下行子载波的流程示意图；
图11是本申请一个示例性实施例提供的确定叶子节点在下行子载波的信噪比的流程示意图；
图12是本申请一个示例性实施例提供的光通信的装置的结构示意图；
图13是本申请一个示例性实施例提供的光通信的装置的结构示意图。
具体实施方式
为使本申请的目的、技术方案和优点更加清楚，下面将结合附图对本申请实施方式作进一步地详细描述。
下面对本申请实施例涉及的一些术语概念做解释说明。
1、PON，是通过无源光分路器(splitter)形成的无源点到多点的光网络，无源光分路器形成点到多点之间的光分配网络(optical distribution network，ODN)，参见图1所示的PON。PON包括一个中心节点和多个叶子节点。中心节点可以是OLT，叶子节点可以是ONT或者ONU。中心节点也可以称为是局端，叶子节点也可以称为是叶子端。中心节点向叶子节点发送数据的过程称为是下行通信，叶子节点向中心节点发送数据的过程称为是上行通信。
2、频分复用(frequency division multiplexing，FDM)，是将用于传输信道的总带宽划分成若干个子频带(或称为子信道)，每一个子信道传输1路光信号。频分复用要求总频率宽度大于各个子信道频率之和，同时为了保证各子信道中所传输的信号互不干扰，应在各子信道之间设置隔离带，这样就保证了各路光信号互不干扰。
3、相干接收，利用调制信号的载波和接收到的已调信号相乘，然后通过低通滤波得到调制信号的接收方式。
下面描述本申请实施例的相关背景。
在一种传统的PON中，参见图2所示的PON，中心节点与叶子节点之间采用波分复用的方式传输数据。中心节点能够发出多个频率的光，每个频率的光对应一个叶子节点，作为叶子节点的光载波。中心节点为每个叶子节点调制不同频率的光载波信号，中心节点连接的波分复用器将多个频率的光载波信号合并，通过光纤传输至叶子节点侧，中心节点连接的解复用器将各个频率的光载波信号进行分离，分别传输至各个叶子节点。这样，中心节点需要为每个叶子节点调制不同频率的光载波信号，PON中的叶子节点数量一般比较多，中心节点需要发出多种不同频率的光，进而需要多个激光器，会导致中心节点的处理过程比较复杂。
在另一种传统的PON中，叶子节点向中心节点发送数据采用时分复用(time division multiplexing，TDM)的方式，中心节点向叶子节点发送数据采用广播的方式。这样，在叶子节点向中心节点发送数据的上行方向，时分复用体现为每个叶子节点发送持续一段时间的突发(burst)数据包。在中心节点向叶子节点发送数据虽然采用广播方式，但是叶子节点只提 取属于自己占据一段时间的数据包，所以也可以认为是在时间维度上进行复用。PON中采用这种方式传输数据，使得叶子节点的数据不能被及时发送。而且在部分叶子节点故障后，在其他叶子节点对应的时间段内，也发送数据，会造成整个PON故障。
本申请中，中心节点生成多个下行子载波对应的下行频分复用电信号，多个下行子载波中至少一个下行子载波上编码有多个叶子节点的数据。然后再将下行频分复用电信号调制到第一频率的信号光上，获得下行频分复用光信号。中心节点发送下行频分复用光信号。这样，由于中心节点仅提供一个频率的信号光，使得中心节点仅需要一个信号光的激光器，简化中心节点的处理过程。而且至少一个下行子载波上编码有多个叶子节点的数据，使得多个叶子节点的数据能够并行发送，能够降低叶子节点的数据的发送延时。而且由于各个叶子节点能够同时发送数据，所以在部分叶子节点故障后，不会由于故障的叶子节点也发出光信号而造成整个PON故障。
在本申请实施例中，下行子载波为用于下行通信的子载波，上行子载波为用于上行通信的子载波。
下面描述本申请实施例的***架构。
本申请中的技术方案可以应用于包含PON的通信***中，本申请实施例对通信***不进行限定。例如，通信***为码分多址(code division multiple access，CDMA)***、宽带码分多址(wideband code division multiple access，WCDMA)***、通用分组无线业务(general packet radio service，GPRS)、长期演进(long term evolution，LTE)***或第五代移动通信技术(5th-generation，5G)等。
PON包括中心节点和多个叶子节点，中心节点与多个叶子节点通过ODN连接。中心节点能够发出第一频率的信号光，并且能够发出第三频率的本振光，本振光也可以称为是本征光，第一频率的信号光用于在下行通信中作为光载波，第三频率的本振光用于在上行通信中相干接收叶子节点发送的光信号。叶子节点能够发出第二频率的信号光，并且能够发出第四频率的本振光，第二频率的信号光用于在上行通信中作为光载波，第四频率的本振光用于在下行通信中相干接收中心节点发送的光信号，不同叶子节点对应的第二频率有可能相同或者不相同，不同叶子节点对应的第四频率有可能相同或者不相同。图3示出了上行通信中叶子节点1和叶子节点2对应的第二频率相同，叶子节点1与叶子节点3对应的第二频率不相同，说明叶子节点1和叶子节点2共用一个上行子载波，叶子节点3未与叶子节点1共用该上行子载波。图4示出了下行通信中叶子节点1和叶子节点2对应的第四频率相同，叶子节点1与叶子节点3对应的第四频率不相同，说明叶子节点1和叶子节点2共用一个下行子载波，叶子节点3未与叶子节点1共用该下行子载波。
需要说明的是，对于一个叶子节点来说，第二频率可以是一个或者多个，第二频率是一个时，说明该叶子节点对应一个上行子载波，第二频率是多个时，说明该叶子节点对应多个上行子载波。同理，对于一个叶子节点来说，第四频率可以是一个或者多个，第四频率是一个时，说明该叶子节点对应一个下行子载波，第四频率是多个时，说明该叶子节点对应多个下行子载波。
还需要说明的是，中心节点与叶子节点之间使用一根光纤进行通信，上行通信和下行通信使用的光的频率不相同。
下面描述本申请实施例的执行主体。
本申请实施例中的执行主体可以是中心节点和/或叶子节点，中心节点可以是OLT，叶子节点可以是ONT或者ONU。
中心节点包括发射机和接收机，参见图5所示的发射机，发射机包括数字信号处理器(digital signal process，DSP)、数模转换器(digital to analog converter，DAC)、驱动器、光调制器和激光器，DSP是处理器中的一种。DSP用于产生数字域的信号。数模转换器用于生成电域上的频分复用电信号。驱动器用于对频分复用信号进行放大处理。光调制器用于将频分复用电信号调制到激光器发出的信号光上。在发射机中，驱动器是可选的。
接收机为相干接收机，参见图6所示的接收机，接收机包括混频器、探测器、模数转换器(analog-to-digital converter，ADC)和DSP。混频器用于将接收到的光信号与本振光混频。探测器用于将混频后的光信号转换为电信号。ADC用于将电信号转换到数字域的信号。DSP用于从数字域上的信号中获得数据。
叶子节点也包括发射机和接收机，发射机与中心节点的发射机类似，接收机与中心节点的接收机类似，此处不再赘述。
需要说明的是，上述发射机和接收机仅是一种示例，本申请实施例不对发射机和接收机的具体结构进行限定。例如，发射机和接收机的DSP是同一个DSP。
示例性的，中心节点和叶子节点还包括存储器，存储器用于存储光通信中需要的数据，例如，中心节点的存储器用于存储每个叶子节点对应的下行子载波的中心频率等，叶子节点的存储器用于存储在上行子载波上的编码功率比例等。
下面描述光通信的流程中中心节点和叶子节点通信的处理流程，参见图7所示的光通信的流程中步骤701至步骤703。在图7中，以中心节点为OLT、叶子节点为ONT为例进行方案的说明。
步骤701，中心节点基于各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，生成多个下行子载波对应的下行频分复用电信号，该各叶子节点接入该中心节点，该多个下行子载波中至少一个下行子载波上编码有多个叶子节点的数据。
其中，每个下行子载波在频域上不重叠。每个叶子节点能够对应一个或多个下行子载波。每个下行子载波上能够编码一个或多个叶子节点的数据。例如，图8示出了多个叶子节点共用下行子载波的示意图，在频率、功率和时间组成的三维坐标系中，在同一时间范围内叶子节点1和叶子节点2共用下行子载波1(如在t1至t2时间段，叶子节点1和叶子节点2同时使用下行子载波1，在t2至t3时间段，叶子节点1和叶子节点2同时使用下行子载波1)，在同一时间范围内叶子节点3和叶子节点4共用下行子载波2，在同一时间范围内叶子节点4和叶子节点5共用下行子载波3等。编码功率比例用于指示在下行子载波上编码叶子节点的数据时所使用的编码功率占该总功率的比例，该总功率为下行子载波对应的编码功率。例如，在叶子节点单独占用一个下行子载波时，在该下行子载波上编码数据时所使用的编码功率等于该下行子载波的总功率，编码功率比例为1，在多个叶子节点占用一个下行子载波时，在该下行子载波上编码多个叶子节点的数据时所使用的编码功率之和等于该下行子载波的总功率，编码功率比例均小于1。每个下行子载波上编码数据时所使用的编码功率可以相同，也可以不相同。
在本实施例中，中心节点确定接入该中心节点的叶子节点，也就是确定在中心节点上进行注册过的叶子节点，相当于中心节点与各叶子节点建立有连接。中心节点在向各叶子节点 发送数据时，中心节点获取各叶子节点对应的下行子载波，并且获取各叶子节点在对应的下行子载波上的编码功率比例。此处各叶子节点是与中心节点进行通信的全部叶子节点，或者各叶子节点是与中心节点进行通信的部分叶子节点，该部分叶子节点有可能是有数据要接收，该部分叶子节点也有可能是由于与其它叶子节点共用下行子载波，共用的下行子载波上有可能是编码了该多个叶子节点的业务数据，共用的下行子载波上也有可能是编码了部分叶子节点的业务数据，以及另一部分叶子节点对应的预设数据，在下行子载波上编码预设数据是为了使得共用下行子载波的叶子节点能够解码获得自身的数据。
中心节点使用各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，将各叶子节点的数据编码到对应的下行子载波上，生成多个下行子载波对应的下行频分复用电信号。
示例性的，中心节点可以通过如下方式生成下行频分复用电信号：中心节点使用每个下行子载波对应的总功率和各叶子节点在对应的下行子载波上的编码功率比例，将各叶子节点的数据编码到对应的下行子载波上，生成每个下行子载波对应的基带信号。然后对应每个下行子载波，中心节点将该下行子载波对应的基带信号频移处理，获得该下行子载波对应的下行子载波信号。中心节点将各个下行子载波对应的下行子载波信号合并，基于合并后的信号得到下行频分复用电信号。
此处是生成下行频分复用电信号的一种示例，本申请实施例对此不作限定。
需要说明的是，在同一个下行子载波上编码多个叶子节点的数据的编码方式相同。
步骤702，中心节点将该下行频分复用电信号调制到第一频率的信号光上，获得下行频分复用光信号。
其中，第一频率的信号光由中心节点包括的激光器发出，第一频率的信号光是单个频率的光。
在本实施例中，中心节点生成下行频分复用电信号后，将下行频分复用电信号通过光调制器调制到第一频率的信号光上，获得下行频分复用光信号。
示例性的，步骤701和步骤702可以由中心节点中的发射机完成。例如，发射机包括DSP、DAC、驱动器、光调制器和激光器。DSP将各叶子节点对应的数据编码到对应的下行子载波上，在数据域生成每个下行子载波对应的基带信号。然后DSP对基带信号在数字域实现频移，使得各基带信号的频率频移至对应的子载波上，得到每个下行子载波对应的下行子载波信号。然后DSP将每个下行子载波信号相加送往DAC。DAC对相加获得的下行子载波信号进行转换，得到下行频分复用电信号。驱动器对下行频分复用电信号进行放大处理，光调制器将下行频分复用电信号调制到第一频率的信号光上，获得下行频分复用光信号。
步骤703，中心节点发送该下行频分复用光信号。
在本实施例中，中心节点获得下行频分复用光信号后，使用PON中的ODN将该下行频分复用光信号，发送到接入中心节点的各个叶子节点。
下面描述光通信的流程中叶子节点的处理流程，参见图9所示的流程中步骤901至步骤903。
步骤901，第一叶子节点接收中心节点发送的下行频分复用光信号，该下行频分复用光信号调制在第一频率的信号光上。
其中，第一叶子节点为接入中心节点的任一叶子节点。
步骤902，第一叶子节点通过该下行频分复用光信号，获得该第一叶子节点对应的下行子载波电信号，该下行子载波电信号为在该叶子节点对应的下行子载波上编码数据获得的信号，该下行子载波上编码有多个叶子节点的数据。
在本实施例中，在第一叶子节点是相干接收中心节点发送的光信号时，第一叶子节点将本振光的频率设置为对应的下行子载波的中心频率。第一叶子节点使用该本振光相干接收下行频分复用光信号，获得第一叶子节点对应的下行子载波电信号。
示例性的，第一叶子节点使用接收机获得下行子载波电信号，处理过程如下：
接收机中混频器将下行频分复用光信号与第四频率的本振光进行混频处理，经过探测器检测后转换为电信号，该电信号的中心频率等于该本振光的频率。接收机采用ADC将电信号转换到数字域，通过带通滤波或者频移后滤波处理得到第一叶子节点对应的下行子载波电信号。
步骤903，第一叶子节点基于非正交的解码方式，在该下行子载波电信号中解码获得该第一叶子节点的数据，非正交的解码方式是基于多个叶子节点在所述下行子载波上的编码功率比例确定的。
在本实施例中，若第一叶子节点对应的下行子载波上编码有多个叶子节点的数据，则第一叶子节点基于非正交的解码方式，在下行子载波电信号上获得第一叶子节点的数据。例如，第一叶子节点先将编码功率比例较大的信号作为有用信号，其它信号作为干扰进行解码，然后将解码出的有用信号减去，依次类推，直到解码出第一叶子节点的信号，从该信号中提取出第一叶子节点的数据。若第一叶子节点对应的下行子载波上仅编码有第一叶子节点的数据，则第一叶子节点直接在下行子载波电信号上，解码获得第一叶子节点的数据。
示例性的，在第一叶子节点和第二叶子节点共有下行子载波时，第一叶子节点解码出自身的数据的方式如下：
第一叶子节点对应的下行子载波上编码有两个叶子节点的数据，该两个叶子节点包括第一叶子节点和第二叶子节点，若第一叶子节点的编码功率低于第二叶子节点的编码功率，在第一叶子节点的接收地点，第二叶子节点信号的信噪比大于第一叶子节点信号的信噪比，第一叶子节点先从下行子载波电信号上解码获得第二叶子节点的信号，然后第一叶子节点再将下行子载波电信号减去第二叶子节点的信号，最终解码出第一叶子节点的信号，进而获得第一叶子节点的数据。若第一叶子节点的编码功率高于第二叶子节点的编码功率，此时第一叶子节点的信号已经过较大的链路损耗，接收信号的信噪比较低，且整体信号中第一叶子节点的信号功率占比大，所以第一叶子节点的信号的信噪比高于第二叶子节点的信号的信噪比，下行子载波电信号都是第一叶子节点的数据，因此，可以直接获得第一叶子节点的信号，而不用依次解码，此处“直接”表示第一次解码获得信号就属于第一叶子节点。此处是以一个下行子载波对应两个叶子节点为例进行说明，在一个下行子载波上对应三个叶子节点时，可以按照解码两个叶子节点的方式，按照信噪比从高到低的顺序依次解码获得各叶子节点的信号。
基于上述描述可知，采用图7和图9所示的流程，中心节点仅发出单个频率的信号光就能实现下行通信，能够减少信号光的激光器的数量。而且多个下行子载波中至少一个下行子载波上编码有多个叶子节点的数据，使得多个叶子节点的数据能够并行发送，提高数据发送效率。而且在叶子节点的数目比较多的情况下，能够减少频谱占用，节约频谱资源。
需要说明的是，在图9所示的流程中，在每个叶子节点仅对应一个下行子载波的情况下，也能使用直接检测的方式接收自身对应的数据。
下面对图7和图9所示的流程进行进一步说明。
在一种可能的实现方式中，中心节点使用信噪比确定各叶子节点对应的下行子载波，处理流程见图10中步骤1001至步骤1004：
步骤1001，中心节点获取该各叶子节点在所能接收的下行子载波上的信噪比。
其中，对于某个叶子节点来说，所能接收的下行子载波为能够相干接收的下行子载波，也就是说该叶子节点能够提供频率为该下行子载波的中心频率的本振光。
在本实施例中，中心节点可以使用中心节点与各叶子节点之间的距离，确定各叶子节点在所能接收的下行子载波上的信噪比。例如，对于任一叶子节点，假设该叶子节点在每个所能接收的下行子载波上的信噪比相同，中心节点使用预设的距离与信噪比的对应关系，确定出叶子节点在每个下行子载波上的信噪比。在该对应关系中，叶子节点与中心节点的距离越远，信噪比越低，叶子节点与中心节点的距离越近，信噪比越高。
或者，中心节点可以获取各叶子节点上报的信噪比。处理流程参见图11所示的流程。
步骤1101，中心节点广播该多个下行子载波对应的功率测试光信号。
其中，功率测试光信号用于指示叶子节点上报接收到的下行子载波的光信号的光功率。
在本实施例中，每个下行子载波上使用相同编码方式编码相同的数据，该相同的数据用于指示叶子节点接收到后上报接收功率，编码方式可以是任意的，如编码方式采用四相位键控(quadrature phase shift keying，QPSK)等。中心节点生成下行频分复用电信号，将该下行频分复用电信号调制到第一频率的信号光上，获得下行频分复用光信号，也就是多个下行子载波对应的功率测试光信号。
示例性的，每个下行子载波上编码数据时使用的编码功率可以相同，也可以不相同。
步骤1102，第一叶子节点接收该中心节点广播的多个下行子载波对应的功率测试光信号。
步骤1103，第一叶子节点测量获得该多个下行子载波中至少一个下行子载波对应的接收功率。
其中，接收功率为至少一个下行子载波对应的光信号的光功率。
在本实施例中，第一叶子节点发出本振光，该本振光的频率与至少一个下行子载波的中心频率相同，或者相近，此处第一叶子节点发出的本振光的频率可以预先配置。第一叶子节点相干接收至少一个下行子载波，获得至少一个下行子载波对应的接收功率。
步骤1104，第一叶子节点向该中心节点发送该接收功率。
在本实施例中，第一叶子节点向中心节点发送接收功率与下行子载波的中心频率的对应关系。示例性的，第一叶子节点使用预设的子载波向中心节点发送接收功率，此时每个叶子节点可以使用不同的上行子载波。
步骤1105，中心节点接收第一叶子节点发送的至少一个下行子载波对应的接收功率。
步骤1106，中心节点基于接收到的接收功率，确定各叶子节点在所能接收的下行子载波上的信噪比。
其中，信噪比等于信号最大功率幅值与噪声最大功率幅值的比值。该信噪比指光信噪比。叶子节点所能接收的下行子载波为叶子节点能够相干接收的下行子载波，即叶子节点能够发出该下行子载波的中心频率的本振光。
在本实施例中，假设中心节点广播光功率测试信号时，每个下行子载波对应的编码功率相同，说明叶子节点在每个下行子载波上的信噪比相同。对于第一叶子节点，中心节点计算出第一叶子节点在其中一个下行子载波上的信噪比，可以确定出在所有下行子载波上的信噪比。
确定信噪比的过程为：假设第一叶子节点接收下行子载波1对应的信号的接收功率为y，该接收功率y为光功率，首先将该接收功率y转换为下行子载波1的各频率的功率x，该功率x为电信号的功率。在计算第一叶子节点在下行子载波1对应的信噪比时，信号功率P1为P1＝E(|x| 2)，噪声功率P2为
Figure PCTCN2022142306-appb-000001
信噪比等于
Figure PCTCN2022142306-appb-000002
在P1的表达式中，E(|x| 2)表示x 2的期望值，在P2的表达式中，
Figure PCTCN2022142306-appb-000003
表示x由DSP恢复后的判决值，例如，恢复的信号的数值为0.9，更接近于1，判决值即为1，
Figure PCTCN2022142306-appb-000004
表示
Figure PCTCN2022142306-appb-000005
的期望值。
另外，在中心节点广播光功率测试信号时，下行子载波对应的编码功率有可能不完全相同，此时需要叶子节点向中心节点发送所能接收的每个下行子载波对应的接收功率。
步骤1002，中心节点基于该各叶子节点在所能接收的下行子载波上的信噪比，确定该各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，在目标下行子载波上，第一叶子节点对应的编码功率比例低于第二叶子节点对应的编码功率比例，该第一叶子节点对应的信噪比高于该第二叶子节点对应的信噪比。
在本实施例中，中心节点获取到各叶子节点在所能接收的下行子载波上的信噪比后，可以使用该信噪比，确定出各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例。需要说明的是，为各叶子节点分配的下行子载波，均属于各叶子节点所能接收的下行子载波。
需要说明的是，在步骤1002中，若某些叶子节点已经预先配置有对应的下行子载波，则这些叶子节点不再需要使用信噪比确定对应的下行子载波的中心频率。当然这些叶子节点也不需要上报接收功率。因此，图11所示的流程中的叶子节点是需要使用信噪比确定对应下行子载波的叶子节点。
示例性的，每个下行子载波最多对应两个叶子节点，即每个下行子载波最多用于编码两个叶子节点的数据。中心节点确定各叶子节点对应的下行子载波的中心频率的处理过程为：
在该多个下行子载波中，为信噪比的差值大于或等于目标阈值的两个叶子节点分配相同的下行子载波。
其中，目标阈值可以预设，并且存储至中心节点中。例如，目标阈值为10dB等。
在本实施例中，中心节点在为各叶子节点分配下行子载波时，为信噪比的差值大于或等于目标阈值的两个叶子节点分配相同的下行子载波，即对于同一个下行子载波上对应的两个叶子节点，该两个叶子节点在该下行子载波上的信噪比的差值大于或等于目标阈值。例如，第一叶子节点和第二叶子节点共用目标下行子载波时，第一叶子节点在目标下行子载波和第二叶子节点在目标下行子载波上的信噪比的差值大于或等于目标阈值。
另外，对于某个叶子节点，不存在与其它叶子节点的信噪比的差值大于或等于目标阈值的下行子载波，则该叶子节点单独使用一个下行子载波。
示例性的，对于每个下行子载波，中心节点确定出能接收该下行子载波的叶子节点，计 算在该下行子载波上信噪比差值大于或等于目标阈值的叶子节点。然后综合考虑每个叶子节点所需要的下行子载波的数目，确定出为每个叶子节点分配的下行子载波。例如，发往第一叶子节点的数据量比较多，需要使用3个下行子载波，第一叶子节点也可以与其他叶子节点共用6个下行子载波，或者共用4个下行子载波，并单独占用一个下行子载波。
示例性的，每个叶子节点所需要的下行子载波的数目可以是预先配置的。例如，每个叶子节点对应两个下行子载波。或者每个叶子节点所需要的下行子载波的数目可以是根据每个叶子节点接收的数据量决定的，接收的数据量越多，分配的下行子载波的数目越多，接收的数据量越少，分配的下行子载波的数目越少。需要说明的是，每个下行子载波对应的叶子节点的数目可以根据实际需要设置，例如，对于任一下行子载波，该下行子载波上编码目标数目个叶子节点的数据后，目标数目个叶子节点能够各自解码获得自身的数据，该下行子载波上编码目标数目加一个叶子节点的数据后，这些叶子节点不能正确解码获得自身的数据，该下行子载波对应的叶子节点的数目最多为目标数目。
示例性的，在确定出每个叶子节点对应的下行子载波的中心频率后，使用每个叶子节点在对应的下行子载波上的信噪比，确定每个叶子节点在对应的下行子载波上的编码功率比例。例如，第一叶子节点和第二叶子节点共用目标下行子载波，第一叶子节点在目标下行子载波上的信噪比高于第二叶子节点在目标下行子载波上的信噪比，假设第一叶子节点在目标下行子载波上的编码功率比例等于N/M，第二叶子节点在目标下行子载波上的编码功率比例等于(M-N)/M，N/M小于(M-N)/M，且N/M与(M-N)/M之和等于1。本申请实施例对M和N的取值不做具体限定。这样，目标下行子载波的总功率为P时，第一叶子节点使用的编码功率为N*P/M，第二叶子节点使用的编码功率为(M-N)*P/M。
需要说明的是，在叶子节点单独使用一个下行子载波时，该叶子节点在该下行子载波上的编码功率比例为1。
还需要说明的是，在三个及三个以上的叶子节点共用一个下行子载波时，每个叶子节点对应的编码功率比例可以是根据实际需要设定，目标是使得每个叶子节点均能解码获得自身的数据。
示例性的，在多个下行子载波中，对应有多个叶子节点的下行子载波的中心频率低于对应有一个叶子节点的下行子载波的中心频率。这样，中心频率低的下行子载波的信噪比比较高，中心频率低的下行子载波用于多个叶子节点共用，即使多个叶子节点共用中心频率低的下行子载波，也能解析出各自的数据。中心频率高的下行子载波的信噪比比较低，中心频率高的下行子载波用于承载单个叶子节点的数据。采用这种方式，尽可能保证各叶子节点的数据能够正确被解码。
步骤1003，中心节点向该各叶子节点发送第一消息，该第一消息用于指示该各叶子节点分别对应的下行子载波的中心频率。
在本实施例中，中心节点广播第一消息，第一消息用于指示各叶子节点分别对应的下行子载波的中心频率。接入中心节点的每个叶子节点均能接收到第一消息。例如，中心节点在每个下行子载波上编码该第一消息，使得叶子节点可以接收到该第一消息，第一消息的消息字段中包括各叶子节点分别对应的下行子载波的中心频率。
示例性的，在一个下行子载波上编码多个叶子节点的数据时，第一消息还用于指示各叶子节点在对应的下行子载波上的解码方式。例如，第一消息的消息字段中还包括解码方式， 确定解码方式的处理过程为：
基于该各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，确定该各叶子节点在对应的下行子载波的解码方式，该解码方式为该各叶子节点在对应的下行子载波上解码数据的方式。
在本实施例中，对于某个下行子载波，若该下行子载波对应多个叶子节点，则该多个叶子节点的解码方式均属于非正交的解码方式，但是具体的解码方式有一定区别。例如，信噪比低的叶子节点的编码功率高，对于同对应一个下行子载波的其他叶子节点来说，造成的干扰就越大。每个叶子节点可以先解码获得当前编码功率最大的叶子节点的信号，从整个下行子载波的信号中减去编码功率最大的叶子节点的信号，接着对编码功率次最大的信号进行解码，依此类推，直至分离出所有叶子节点的信号。对于每个叶子节点来说，叶子节点需要知晓第几次解析出的信号属于自身，解码方式中会进行指示。
对于某个下行子载波，若该下行子载波对应一个叶子节点，则解码方式为正交解码方式，每个叶子节点可以直接解码获得属于自身的信号。
步骤1004，第一叶子节点接收第一消息，该第一消息用于指示各叶子节点分别对应的下行子载波的中心频率和在对应的下行子载波上的解码方式。
在本实施例中，第一叶子节点在第一消息中获取自身对应的下行子载波的中心频率，将本振光的频率调整至与对应的下行子载波的中心频率相同。这样，第一叶子节点能够相干接收中心节点发送的数据。并且第一叶子节点存储在对应的下行子载波上的解码方式。
需要说明的是，在中心节点和叶子节点部署上线时，可以执行图10所示的流程，为各叶子节点分配下行子载波。或者，在中心节点和叶子节点部署上线后，周期性执行图10所示的流程，这样，可以合理调整为叶子节点分配的下行子载波。或者在中心节点新接入一个或多个叶子节点后，执行图10所示的流程。或者，在叶子节点上报长时间未接收到中心节点发送的数据时，执行图10所示的流程。此处仅是四种可能的方式，本申请实施例对此不进行限定。
在一种可能的实现方式中，中心节点还可以为各叶子节点分配上行子载波，处理方式为：
中心节点获取该各叶子节点在所能发送的上行子载波上的信噪比；基于该各叶子节点在所能发送的上行子载波上的信噪比，确定该各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例，在目标上行子载波上，第三叶子节点对应的编码功率比例低于第四叶子节点对应的编码功率比例，该第三叶子节点对应的信噪比高于该第四叶子节点对应的信噪比；向该各叶子节点发送第二消息，该第二消息用于指示该各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例。
在本实施例中，中心节点可以获取各叶子节点在所能发送的上行子载波上的信噪比。中心节点在为各叶子节点分配上行子载波时，为信噪比的差值大于或等于目标阈值的两个叶子节点分配相同的上行子载波，即对于同一个上行子载波上对应的两个叶子节点，该两个叶子节点在该上行子载波上的信噪比的差值大于或等于目标阈值。例如，第三叶子节点和第四叶子节点共用目标上行子载波时，第三叶子节点在目标上行子载波和第四叶子节点在目标上行子载波上的信噪比的差值大于或等于目标阈值。中心节点在确定出各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例后，向各叶子节点发送第二消息，该第二消息的消息字段中包括各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例。各叶子节点获取到第二消息后，从中解析获得自身对应的上行子载波 的中心频率和在对应的上行子载波上的编码功率比例。
另外，对于某个叶子节点，在不存在与其它叶子节点的信噪比的差值大于或等于目标阈值的上行子载波时，该叶子节点单独使用一个上行子载波。
示例性的，中心节点获取各叶子节点在所能发送的上行子载波上的信噪比的方式为：
中心节点获取各叶子节点在每个下行子载波上的信噪比。由于中心节点向叶子节点发送数据，以及叶子节点向中心节点发送数据使用同一根光纤，因此，可以使用每个下行子载波上的信噪比确定各叶子节点在所能发送的上行子载波上的信噪比。例如，对于某个叶子节点，确定该叶子节点对应的第一下行子载波的中心频率与第一频率的差值，确定距离第三频率等于该差值位置处的频率，将该叶子节点在第一下行子载波上的信噪比，确定为中心频率为该频率的上行子载波的信噪比。该叶子节点在每个上行子载波上的信噪比相同，均为确定出的该信噪比。基于这种方式能够确定出各叶子节点在所能发送的上行子载波上的信噪比。
需要说明的是，上行子载波和下行子载波的带宽相同。对于某个叶子节点，每个上行子载波的编码功率相同。
示例性的，对于每个上行子载波，中心节点确定出能发送该上行子载波的叶子节点，计算在该上行子载波上信噪比差值大于或等于目标阈值的叶子节点。然后综合考虑每个叶子节点所需要的上行子载波的数目，确定出为每个叶子节点分配的上行子载波。
示例性的，每个叶子节点所需要的上行子载波的数目可以是预先配置的，例如，每个叶子节点对应两个上行子载波。或者每个叶子节点所需要的上行子载波的数目可以是根据每个叶子节点发送的数据量决定的，发送的数据量越多，分配的上行子载波的数目越多，发送的数据量越少，分配的上行子载波的数目越少。需要说明的是，每个上行子载波对应的叶子节点的数目可以根据实际需要设置，例如，对于任一上行子载波，该上行子载波上编码目标数目个叶子节点的数据后，中心节点能够解码获得目标数目个叶子节点的数据，该上行子载波上编码目标数目加一个叶子节点的数据后，中心节点不能解码获得目标数目个叶子节点的数据，该上行子载波对应的叶子节点的数目最多为目标数目。
示例性的，在确定出每个叶子节点对应的上行子载波的中心频率后，确定每个叶子节点在对应的上行子载波上的编码功率比例。例如，第三叶子节点和第四叶子节点共用目标上行子载波，第三叶子节点在目标上行子载波上的信噪比高于第四叶子节点在目标上行子载波上的信噪比，假设第三叶子节点在目标上行子载波上的编码功率比例等于N1/M1，第四叶子节点在目标上行子载波上的编码功率比例等于(M1-N1)/M1，N1/M1小于(M1-N1)/M1，且N1/M1与(M1-N1)/M1之和等于1。本申请实施例对M1和N1的取值不做具体限定。这样，目标上行子载波的总功率为P1时，第三叶子节点使用的编码功率为N1*P1/M1，第四叶子节点使用的编码功率为(M1-N1)*P1/M1。
需要说明的是，对于叶子节点单独使用一个上行子载波时，该叶子节点在该上行子载波上的编码功率比例为1。
示例性的，在多个上行子载波中，对应有多个叶子节点的上行子载波的中心频率低于对应有一个叶子节点的上行子载波的中心频率。这样，中心频率低的上行子载波的信噪比比较高，中心频率低的上行子载波用于多个叶子节点共享，即使多个叶子节点共享，也能解析出各自的数据。中心频率高的上行子载波的信噪比比较低，中心频率高的上行子载波用于承载单个叶子节点的数据。
需要说明的是，各叶子节点对应的下行子载波的中心频率、上行子载波的中心频率以及解码方式可以设置在同一条消息中一起发送，或者单独发送。
在一种可能的实现方式中，第一叶子节点向中心节点发送数据前，第一叶子节点接收第二消息，在发送数据时，第一叶子节点基于第一叶子节点在目标上行子载波对应的编码功率比例，生成目标上行子载波对应的上行电信号，该目标上行子载波为该第一叶子节点对应的上行子载波；将该上行电信号调制到第二频率的信号光上，获得上行光信号，该第二频率与该目标上行子载波的中心频率相同；第一叶子节点发送该上行光信号。
在本实施例中，第一叶子节点接收第二消息，按照第二消息中指示的第一叶子节点对应的上行子载波的中心频率，将发出的信号光的频率调整为该中心频率。并且第一叶子节点存储在对应的上行子载波上的编码功率比例。
当第一叶子节点在发送上行数据时，发射机中的DSP使用该编码功率比例，生成目标上行子载波对应的基带信号。然后DSP将该基带信号进行频移处理，使得该基带信号的频率频移至对应的目标上行子载波上，得到目标上行子载波对应的上行子载波信号，DSP将该上行子载波信号发送给DAC。DAC对该上行子载波信号进行转换，得到上行电信号，驱动器对该上行电信号进行放大处理。光调制器将该上行电信号调制到第二频率的信号光上，获得上行光信号。此处第二频率与目标上行子载波的中心频率相同，也即信号光的频率与目标上行子载波的中心频率相同。
在一种可能的实现方式中，中心节点可以接收叶子节点发送的上行数据，处理过程为：
中心节点接收上行频分复用光信号；在该上行频分复用光信号中，通过相干接收获得该各叶子节点的数据。
在本实施例中，各个叶子节点发送的上行光信号，通过PON中的ODN汇聚到一根光纤中，发送给中心节点。中心节点接收到的光信号为上行频分复用光信号。中心节点在上行频分复用光信号中，相干接收各叶子节点的数据。例如，中心节点使用第三频率的本振光与上行频分复用光信号进行混频，经过探测器后，获得以第三频率为中心的电信号。然后对该电信号分别进行频移至各个上行子载波的中心频率处，然后通过带通滤波处理得到各叶子节点对应的上行电信号，进而获得各叶子节点对应的上行数据。
需要说明的是，第三频率的本振光是所有上行子载波的中心频率。在单个上行子载波上对应多个叶子节点时，多个叶子节点发送上行数据时，携带有叶子节点的标识，中心节点可以使用叶子节点的标识区分各个叶子节点的数据。
上述光通信的流程中，是控制编码功率，使得不同的叶子节点使用相同的下行子载波，或者使用相同的上行子载波，从而实现多个叶子节点的非正交编码。在另一种实现中，也可以基于稀疏码分复用(sparse code multiple access，SCMA)的非正交编码方式，使得多个叶子节点的数据共用上行子载波或者下行子载波。例如，每6个叶子节点共用4个下行子载波，每个子载波上编码两个叶子节点的数据，在同一下行子载波上，两个叶子节点的数据使用不同的编码方式进行编码。
采用本申请实施例的方案，PON是基于频分复用，而不是基于时分复用，多个叶子节点的数据可以同时并行被发送，相对能够降低数据传输的时延。这样，对于工业园区、交通等对传输时延要求较高的场景中，可以降低数据传输的时延。
而且现有的频分复用技术，需要在不同叶子节点的光载波之间预留保护间隔。然而，本 申请实施例中将多个叶子节点的数据同时编码到一个或多个子载波上，能够节约频谱资源，提升***整体带宽。这样，在未来物联网(internet of things，IOT)万物互联场景和有大量并发连接用户的场景可以节约频谱资源。
下面描述本申请实施例提供的装置。
图12是本申请实施例提供的光通信的装置的结构图。该装置可以通过软件、硬件或者两者的结合实现成为装置中的部分或者全部，该装置应用于PON中的中心节点。本申请实施例提供的装置可以实现本申请实施例图7所述的流程，该装置包括：生成模块1210、调制模块1220和发送模块1230，其中：
生成模块1210，用于基于各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，生成多个下行子载波对应的下行频分复用电信号，所述各叶子节点接入所述中心节点，所述多个下行子载波中至少一个下行子载波上编码有多个叶子节点的数据，具体可以用于实现步骤701的生成功能以及执行步骤701包含的隐含步骤；
调制模块1220，用于将所述下行频分复用电信号调制到第一频率的信号光上，获得下行频分复用光信号，具体可以用于实现步骤702的调制功能以及执行步骤702包含的隐含步骤；
发送模块1230，用于发送所述下行频分复用光信号，具体可以用于实现步骤703的发送功能以及执行步骤703包含的隐含步骤。
在一种可能的实现方式中，所述装置还包括：获取模块，用于在生成多个下行子载波对应的下行频分复用电信号之前，获取所述各叶子节点在所能接收的下行子载波上的信噪比；
基于所述各叶子节点在所能接收的下行子载波上的信噪比，确定所述各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，在目标下行子载波上，第一叶子节点对应的编码功率比例低于第二叶子节点对应的编码功率比例，所述第一叶子节点对应的信噪比高于所述第二叶子节点对应的信噪比；
所述发送模块1230，还用于向所述各叶子节点发送第一消息，所述第一消息用于指示所述各叶子节点分别对应的下行子载波的中心频率。
在一种可能的实现方式中，所述获取模块获取所述各叶子节点在所能接收的下行子载波上的信噪比，包括：
所述获取模块广播所述多个下行子载波对应的功率测试光信号；所述获取模块接收所述各叶子节点发送的至少一个下行子载波对应的接收功率；所述获取模块基于接收到的接收功率，确定所述各叶子节点在所能接收的下行子载波上的信噪比。
在一种可能的实现方式中，所述第一消息还用于指示所述各叶子节点在对应的下行子载波上的解码方式；
所述获取模块，还用于在向所述各叶子节点发送第一消息之前，基于所述各叶子节点对应的下行子载波和在对应的下行子载波上的编码功率比例，确定所述各叶子节点在对应的下行子载波的解码方式，所述解码方式为所述各叶子节点在对应的下行子载波上解码数据的方式。
在一种可能的实现方式中，每个下行子载波最多对应两个叶子节点；
所述第一叶子节点和所述第二叶子节点在所述目标下行子载波上的信噪比的差值大于或等于目标阈值。
在一种可能的实现方式中，在所述多个下行子载波中，对应有多个叶子节点的下行子载 波的中心频率低于对应有一个叶子节点的下行子载波的中心频率。
在一种可能的实现方式中，所述装置还包括：获取模块，用于获取所述各叶子节点在所能发送的上行子载波上的信噪比；
基于所述各叶子节点在所能发送的上行子载波上的信噪比，确定所述各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例，在目标上行子载波上，第三叶子节点对应的编码功率比例低于第四叶子节点对应的编码功率比例，所述第三叶子节点对应的信噪比高于所述第四叶子节点对应的信噪比；
所述发送模块1230，还用于向所述各叶子节点发送第二消息，所述第二消息用于指示所述各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例。
在一种可能的实现方式中，所述装置还包括：
接收模块，用于接收上行频分复用光信号；在所述上行频分复用光信号中，通过相干接收获得所述各叶子节点的数据。
在一种可能的实现方式中，所述至少一个下行子载波中每个下行子载波上编码的多个叶子节点的数据是基于SCMA的非正交编码。
在图12所示的装置中，生成模块1210对应于中心节点的DSP和DAC，例如，DSP将各叶子节点对应的数据编码到对应的下行子载波上，得到每个下行子载波对应的下行子载波信号，DSP将每个下行子载波对应的下行子载波信号相加后送往DAC，DAC将相加后的信号进行转换，得到下行频分复用电信号。调制模块1220和发送模块1230对应于前文中描述的驱动器和光调制器，例如，驱动器对下行频分复用电信号进行放大处理(是一个可选的处理)，光调制器将下行频分复用电信号调制到第一频率的信号光上，获得下行频分复用光信号，发送下行频分复用光信号。
示例性的，获取模块对应中心节点的发射机和接收机，例如，发射机发出光功率测试信号，接收机接收叶子节点发送的接收功率等，发射机还可以确定信噪比等，以及发送第一消息和第二消息等。接收模块对应中心节点的接收机，例如，接收机中的混频器和探测器相干接收光信号，将光信号转换为电信号，DSP从电信号上解码获得叶子节点的数据等。
图13是本申请实施例提供的光通信的装置的结构图。该装置可以通过软件、硬件或者两者的结合实现成为装置中的部分或者全部，该装置应用于PON中的第一叶子节点。本申请实施例提供的装置可以实现本申请实施例图9所述的流程，该装置包括：接收模块1310和解码模块1320，其中：
接收模块1310，用于接收中心节点发送的下行频分复用光信号，所述下行频分复用光信号调制在第一频率的信号光上，具体可以用于实现步骤901的接收功能以及执行步骤901包含的隐含步骤；
解码模块1320，用于通过所述下行频分复用光信号，获得所述第一叶子节点对应的下行子载波电信号，所述下行子载波电信号为在所述第一叶子节点对应的下行子载波上编码数据获得的信号，所述下行子载波上编码有多个叶子节点的数据；基于非正交的解码方式，在所述下行子载波电信号中解码获得所述第一叶子节点的数据，所述非正交的解码方式是基于所述多个叶子节点在所述下行子载波上的编码功率比例确定的，具体可以用于实现步骤902和步骤903的解码功能以及执行步骤902和步骤903包含的隐含步骤。
在一种可能的实现方式中，所述接收模块1310，还用于在接收下行频分复用光信号之前， 接收第一消息，所述第一消息用于指示各叶子节点分别对应的下行子载波的中心频率和解码方式，所述各叶子节点接入所述中心节点。
在一种可能的实现方式中，所述多个叶子节点包括第一叶子节点和第二叶子节点；
所述解码模块1320基于非正交的解码方式，在所述下行子载波电信号中解码获得所述第一叶子节点的数据，包括：
若所述第一叶子节点的编码功率比例低于所述第二叶子节点的编码功率比例，所述解码模块1320从所述下行子载波电信号中解码获得所述第二叶子节点的信号，在所述下行子载波电信号中减去所述第二叶子节点的信号，获得所述第一叶子节点的信号；若所述第一叶子节点的编码功率比例高于所述第二叶子节点的编码功率比例，所述解码模块1320从所述下行子载波电信号中直接解码获得所述第一叶子节点的信号；
所述解码模块1320从所述第一叶子节点的信号上提取得到所述第一叶子节点的数据。
在一种可能的实现方式中，所述接收模块1310，还用于：
接收第二消息，所述第二消息用于指示各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例，所述各叶子节点接入所述中心节点；
所述装置还包括：发送模块，用于基于所述第一叶子节点在目标上行子载波对应的编码功率比例，生成所述目标上行子载波对应的上行电信号，所述目标上行子载波为所述第一叶子节点对应的上行子载波；
将所述上行电信号调制到第二频率的信号光上，获得上行光信号，所述第二频率与所述目标上行子载波的中心频率相同；
发送所述上行光信号。
在一种可能的实现方式中，所述接收模块1310，还用于：
接收下行频分复用光信号之前，接收所述中心节点广播的多个下行子载波对应的功率测试光信号；
所述装置还包括：发送模块，用于测量获得所述多个下行子载波中至少一个下行子载波对应的接收功率；向所述中心节点发送所述接收功率。
在图13所示的装置中，接收模块1310对应于前文中的混频器，例如，混频器将接收到光信号与本振光混频，实现对下行频分复用光信号的接收。解码模块1320对应于前文中的探测器、ADC和DSP，例如，探测器将混频后的信号转换为下行频分复用电信号，ADC将下行频分复用电信号转换为数字域的信号，DSP从信号中获得第一叶子节点对应的下行子载波电信号，从下行子载波电信号中解码获得第一叶子节点的数据。
示例性的，发送模块对应叶子节点中的发射机，例如，发射机中的DSP将自身的数据编码到对应的下行子载波上，得到下行子载波信号，DSP将下行子载波信号送往DAC，DAC将下行子载波信号进行转换，得到上行电信号，光调制器将上行电信号调制到第二频率的信号光上，获得上行光信号，发送第二频率的信号光。
图12和图13所示的光通信的装置执行光通信的方法的详细过程请参照前面各个实施例中的描述，在这里不进行重复说明。
本领域普通技术人员可以意识到，结合本申请中所公开的实施例中描述的各方法步骤和单元，能够以电子硬件、计算机软件或者二者的结合来实现，为了清楚地说明硬件和软件的可互换性，在上述说明中已经按照功能一般性地描述了各实施例的步骤及组成。这些功能究 竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。本领域普通技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
在本申请所提供的几个实施例中，应该理解到，所揭露的***架构、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，该模块的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个模块或组件可以结合或者可以集成到另一个***，或一些特征可以忽略，或不执行。另外，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口、装置或模块的间接耦合或通信连接，也可以是电的，机械的或其它的形式连接。
该作为分离部件说明的模块可以是或者也可以不是物理上分开的，作为模块显示的部件可以是或者也可以不是物理模块，即可以位于一个地方，或者也可以分布到多个网络模块上。可以根据实际的需要选择其中的部分或者全部模块来实现本申请实施例方案的目的。
另外，在本申请各个实施例中的各模块可以集成在一个处理模块中，也可以是各个模块单独物理存在，也可以是两个或两个以上模块集成在一个模块中。上述集成的模块既可以采用硬件的形式实现，也可以采用软件模块的形式实现。
该集成的模块如果以软件功能模块的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分，或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本申请各个实施例中方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(read-only memory，ROM)、随机存取存储器(random access memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
本申请中术语“第一”“第二”等字样用于对作用和功能基本相同的相同项或相似项进行区分，应理解，“第一”、“第二”之间不具有逻辑或时序上的依赖关系，也不对数量和执行顺序进行限定。还应理解，尽管以下描述使用术语第一、第二等来描述各种元素，但这些元素不应受术语的限制。这些术语只是用于将一元素与另一元素区别分开。例如，在不脱离各种示例的范围的情况下，第一消息可以被称为第二消息，并且类似地，第二消息可以被称为第一消息。第一消息和第二消息都可以是消息，并且在某些情况下，可以是单独且不同的消息。
本申请中术语“至少一个”的含义是指一个或多个，本申请中术语“多个”的含义是指两个或两个以上。
以上描述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到各种等效的修改或替换，这些修改或替换都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (29)

  1. 一种光通信的方法，其特征在于，所述方法应用于无源光网络PON中的中心节点，所述方法包括：
    基于各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，生成多个下行子载波对应的下行频分复用电信号，所述各叶子节点接入所述中心节点，所述多个下行子载波中至少一个下行子载波上编码有多个叶子节点的数据；
    将所述下行频分复用电信号调制到第一频率的信号光上，获得下行频分复用光信号；
    发送所述下行频分复用光信号。
  2. 根据权利要求1所述的方法，其特征在于，所述生成多个下行子载波对应的下行频分复用电信号之前，还包括：
    获取所述各叶子节点在所能接收的下行子载波上的信噪比；
    基于所述各叶子节点在所能接收的下行子载波上的信噪比，确定所述各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，在目标下行子载波上，第一叶子节点对应的编码功率比例低于第二叶子节点对应的编码功率比例，所述第一叶子节点对应的信噪比高于所述第二叶子节点对应的信噪比；
    向所述各叶子节点发送第一消息，所述第一消息用于指示所述各叶子节点分别对应的下行子载波的中心频率。
  3. 根据权利要求2所述的方法，其特征在于，所述获取所述各叶子节点在所能接收的下行子载波上的信噪比，包括：
    广播所述多个下行子载波对应的功率测试光信号；
    接收所述各叶子节点发送的至少一个下行子载波对应的接收功率；
    基于接收到的接收功率，确定所述各叶子节点在所能接收的下行子载波上的信噪比。
  4. 根据权利要求2或3所述的方法，其特征在于，所述第一消息还用于指示所述各叶子节点在对应的下行子载波上的解码方式；
    所述向所述各叶子节点发送第一消息之前，还包括：
    基于所述各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，确定所述各叶子节点在对应的下行子载波的解码方式，所述解码方式为所述各叶子节点在对应的下行子载波上解码数据的方式。
  5. 根据权利要求2至4任一项所述的方法，其特征在于，每个下行子载波最多对应两个叶子节点；
    所述第一叶子节点和所述第二叶子节点在所述目标下行子载波上的信噪比的差值大于或等于目标阈值。
  6. 根据权利要求1至5任一项所述的方法，其特征在于，在所述多个下行子载波中，对应有多个叶子节点的下行子载波的中心频率低于对应有一个叶子节点的下行子载波的中心频率。
  7. 根据权利要求1至6任一项所述的方法，其特征在于，所述方法还包括：
    获取所述各叶子节点在所能发送的上行子载波上的信噪比；
    基于所述各叶子节点在所能发送的上行子载波上的信噪比，确定所述各叶子节点对应 的上行子载波的中心频率和在对应的上行子载波上的编码功率比例，在目标上行子载波上，第三叶子节点对应的编码功率比例低于第四叶子节点对应的编码功率比例，所述第三叶子节点对应的信噪比高于所述第四叶子节点对应的信噪比；
    向所述各叶子节点发送第二消息，所述第二消息用于指示所述各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例。
  8. 根据权利要求1至7任一项所述的方法，其特征在于，所述方法还包括：
    接收上行频分复用光信号；
    在所述上行频分复用光信号中，通过相干接收获得所述各叶子节点的数据。
  9. 根据权利要求1所述的方法，其特征在于，所述至少一个下行子载波中每个下行子载波上基于稀疏码分复用SCMA的非正交编码方式编码多个叶子节点的数据。
  10. 一种光通信的方法，其特征在于，所述方法应用于无源光网络PON中的第一叶子节点，所述方法包括：
    接收中心节点发送的下行频分复用光信号，所述下行频分复用光信号调制在第一频率的信号光上；
    通过所述下行频分复用光信号，获得所述第一叶子节点对应的下行子载波电信号，所述下行子载波电信号为在所述第一叶子节点对应的下行子载波上编码数据获得的信号，所述下行子载波上编码有多个叶子节点的数据；
    基于非正交的解码方式，在所述下行子载波电信号中解码获得所述第一叶子节点的数据，所述非正交的解码方式是基于所述多个叶子节点在所述下行子载波上的编码功率比例确定的。
  11. 根据权利要求10所述的方法，其特征在于，所述接收下行频分复用光信号之前，还包括：
    接收第一消息，所述第一消息用于指示各叶子节点分别对应的下行子载波的中心频率和解码方式，所述各叶子节点接入所述中心节点。
  12. 根据权利要求10或11所述的方法，其特征在于，所述多个叶子节点包括第一叶子节点和第二叶子节点；
    所述基于非正交的解码方式，在所述下行子载波电信号中解码获得所述第一叶子节点的数据，包括：
    若所述第一叶子节点的编码功率比例低于所述第二叶子节点的编码功率比例，则从所述下行子载波电信号中解码获得所述第二叶子节点的信号，在所述下行子载波电信号中减去所述第二叶子节点的信号，获得所述第一叶子节点的信号；若所述第一叶子节点的编码功率比例高于所述第二叶子节点的编码功率比例，则从所述下行子载波电信号中直接解码获得所述第一叶子节点的信号；
    从所述第一叶子节点的信号上提取得到所述第一叶子节点的数据。
  13. 根据权利要求10至12任一项所述的方法，其特征在于，所述方法还包括：
    接收第二消息，所述第二消息用于指示各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例，所述各叶子节点接入所述中心节点；
    基于所述第一叶子节点在目标上行子载波对应的编码功率比例，生成所述目标上行子载波对应的上行电信号，所述目标上行子载波为所述第一叶子节点对应的上行子载波；
    将所述上行电信号调制到第二频率的信号光上，获得上行光信号，所述第二频率与所述目标上行子载波的中心频率相同；
    发送所述上行光信号。
  14. 根据权利要求10至13任一项所述的方法，其特征在于，所述接收下行频分复用光信号之前，还包括：
    接收所述中心节点广播的多个下行子载波对应的功率测试光信号；
    测量获得所述多个下行子载波中至少一个下行子载波对应的接收功率；
    向所述中心节点发送所述接收功率。
  15. 一种光通信的装置，其特征在于，所述装置应用于无源光网络PON中的中心节点，所述装置包括：
    生成模块，用于基于各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，生成多个下行子载波对应的下行频分复用电信号，所述各叶子节点接入所述中心节点，所述多个下行子载波中至少一个下行子载波上编码有多个叶子节点的数据；
    调制模块，用于将所述下行频分复用电信号调制到第一频率的信号光上，获得下行频分复用光信号；
    发送模块，用于发送所述下行频分复用光信号。
  16. 根据权利要求15所述的装置，其特征在于，所述装置还包括：获取模块，用于在生成多个下行子载波对应的下行频分复用电信号之前，获取所述各叶子节点在所能接收的下行子载波上的信噪比；
    基于所述各叶子节点在所能接收的下行子载波上的信噪比，确定所述各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，在目标下行子载波上，第一叶子节点对应的编码功率比例低于第二叶子节点对应的编码功率比例，所述第一叶子节点对应的信噪比高于所述第二叶子节点对应的信噪比；
    所述发送模块，还用于向所述各叶子节点发送第一消息，所述第一消息用于指示所述各叶子节点分别对应的下行子载波的中心频率。
  17. 根据权利要求16所述的装置，其特征在于，所述获取模块获取所述各叶子节点在所能接收的下行子载波上的信噪比，包括：
    所述获取模块广播所述多个下行子载波对应的功率测试光信号；所述获取模块接收所述各叶子节点发送的至少一个下行子载波对应的接收功率；所述获取模块基于接收到的接收功率，确定所述各叶子节点在所能接收的下行子载波上的信噪比。
  18. 根据权利要求16或17所述的装置，其特征在于，所述第一消息还用于指示所述各叶子节点在对应的下行子载波上的解码方式；
    所述获取模块，还用于在向所述各叶子节点发送第一消息之前，基于所述各叶子节点对应的下行子载波的中心频率和在对应的下行子载波上的编码功率比例，确定所述各叶子节点在对应的下行子载波的解码方式，所述解码方式为所述各叶子节点在对应的下行子载波上解码数据的方式。
  19. 根据权利要求16至18任一项所述的装置，其特征在于，每个下行子载波最多对应两个叶子节点；
    所述第一叶子节点和所述第二叶子节点在所述目标下行子载波上的信噪比的差值大于或等于目标阈值。
  20. 根据权利要求15至19任一项所述的装置，其特征在于，在所述多个下行子载波中，对应有多个叶子节点的下行子载波的中心频率低于对应有一个叶子节点的下行子载波的中心频率。
  21. 根据权利要求15至20任一项所述的装置，其特征在于，所述装置还包括：获取模块，用于获取所述各叶子节点在所能发送的上行子载波上的信噪比；
    基于所述各叶子节点在所能发送的上行子载波上的信噪比，确定所述各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例，在目标上行子载波上，第三叶子节点对应的编码功率比例低于第四叶子节点对应的编码功率比例，所述第三叶子节点对应的信噪比高于所述第四叶子节点对应的信噪比；
    所述发送模块，还用于向所述各叶子节点发送第二消息，所述第二消息用于指示所述各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例。
  22. 根据权利要求15至21任一项所述的装置，其特征在于，所述装置还包括：
    接收模块，用于接收上行频分复用光信号；在所述上行频分复用光信号中，通过相干接收获得所述各叶子节点的数据。
  23. 根据权利要求15所述的装置，其特征在于，所述至少一个下行子载波中每个下行子载波上基于稀疏码分复用SCMA的非正交编码方式编码多个叶子节点的数据。
  24. 一种光通信的装置，其特征在于，所述装置应用于无源光网络PON中的第一叶子节点，所述装置包括：
    接收模块，用于接收中心节点发送的下行频分复用光信号，所述下行频分复用光信号调制在第一频率的信号光上；
    解码模块，用于通过所述下行频分复用光信号，获得所述第一叶子节点对应的下行子载波电信号，所述下行子载波电信号为在所述第一叶子节点对应的下行子载波上编码数据获得的信号，所述下行子载波上编码有多个叶子节点的数据；
    基于非正交的解码方式，在所述下行子载波电信号中解码获得所述第一叶子节点的数据，所述非正交的解码方式是基于所述多个叶子节点在所述下行子载波上的编码功率比例确定的。
  25. 根据权利要求24所述的装置，其特征在于，所述接收模块，还用于在接收下行频分复用光信号之前，接收第一消息，所述第一消息用于指示各叶子节点分别对应的下行子载波的中心频率和解码方式，所述各叶子节点接入所述中心节点。
  26. 根据权利要求24或25所述的装置，其特征在于，所述多个叶子节点包括第一叶子节点和第二叶子节点；
    所述解码模块基于非正交的解码方式，在所述下行子载波电信号中解码获得所述第一叶子节点的数据，包括：
    若所述第一叶子节点的编码功率比例低于所述第二叶子节点的编码功率比例，所述解码模块从所述下行子载波电信号中解码获得所述第二叶子节点的信号，在所述下行子载波电信号中减去所述第二叶子节点的信号，获得所述第一叶子节点的信号；若所述第一叶子节点的编码功率比例高于所述第二叶子节点的编码功率比例，所述解码模块从所述下行子 载波电信号中直接解码获得所述第一叶子节点的信号；
    所述解码模块从所述第一叶子节点的信号上提取得到所述第一叶子节点的数据。
  27. 根据权利要求24至26任一项所述的装置，其特征在于，所述接收模块，还用于：
    接收第二消息，所述第二消息用于指示各叶子节点对应的上行子载波的中心频率和在对应的上行子载波上的编码功率比例，所述各叶子节点接入所述中心节点；
    所述装置还包括：发送模块，用于基于所述第一叶子节点在目标上行子载波对应的编码功率比例，生成所述目标上行子载波对应的上行电信号，所述目标上行子载波为所述第一叶子节点对应的上行子载波；将所述上行电信号调制到第二频率的信号光上，获得上行光信号，所述第二频率与所述目标上行子载波的中心频率相同；发送所述上行光信号。
  28. 根据权利要求24至27任一项所述的装置，其特征在于，所述接收模块，还用于接收下行频分复用光信号之前，接收所述中心节点广播的多个下行子载波对应的功率测试光信号；
    所述装置还包括：发送模块，用于测量获得所述多个下行子载波中至少一个下行子载波对应的接收功率；向所述中心节点发送所述接收功率。
  29. 一种光通信***，其特征在于，所述光通信***包括中心节点和叶子节点；
    所述中心节点用于执行如权利要求1至权利要求9中任一项所述的方法；
    所述叶子节点用于执行如权利要求10至权利要求14中任一项所述的方法。
PCT/CN2022/142306 2021-12-31 2022-12-27 光通信的方法、装置和*** WO2023125528A1 (zh)

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