Optical communication device, system and communication method

Abstract

The invention discloses an optical communication device, an optical communication system and an optical communication method. The optical communication device is used for communicating with a plurality of ONUs, the plurality of ONUs comprise a first type of ONUs and a second type of ONUs, MAC protocols supported by the first type of ONUs and the second type of ONUs are different, and uplink wavelengths of the first type of ONUs and the second type of ONUs are overlapped. The optical communication device comprises a first receiving assembly, a second receiving assembly and a processing assembly, the first receiving assembly is used for receiving a first optical signal sent by a first type of ONU in a first time slot group, the second receiving assembly is used for receiving a second optical signal sent by a second type of ONU in a second time slot group, the first time slot group comprises at least one time slot, and the processing assembly is used for processing the first optical signal and the second optical signal. The second time slot group comprises at least one time slot; and the processing component is used for enabling the first time slot group and the second time slot group not to overlap in the time dimension through a first time slot scheduling mechanism. According to the invention, coexistence of ONUs which support different MAC protocols and have overlapped uplink wavelengths in a PON system can be realized.

Description

Optical communication device, system and communication method

[0001] This application claims priority to Chinese patent application number 202310954175.5, filed on July 28, 2023, entitled “Optical communication device, system and communication method,” the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of optical communication technology, and in particular to an optical communication device, system and communication method. Background Art

[0003] A passive optical network (PON) is a point-to-multipoint, single-fiber, bidirectional optical access network. A PON system typically includes an optical line terminal (OLT), an optical distribution network (ODN), and multiple optical network units (ONUs). The OLT connects to multiple ONUs via the ODN.

[0004] With the development of optical communication technology, at least two optical network units (ONUs) supporting different media access control (MAC) protocols will coexist in a PON system. The upstream wavelengths used by these ONUs may overlap, leading to upstream data conflicts between them and affecting the normal operation of the PON system.

[0005] Summary of the Invention

[0006] The present application provides an optical communication device, system and communication method, which can achieve the coexistence of ONUs supporting different MAC protocols and with overlapping upstream wavelengths in a PON system.

[0007] In a first aspect, the present application provides an optical communication device for communicating with multiple ONUs. The multiple ONUs include a first type of ONU and a second type of ONU, wherein the first type of ONU and the second type of ONU support different MAC protocols, and the upstream wavelengths of the first type of ONU and the second type of ONU overlap. The optical communication device includes a first receiving component, a second receiving component, and a processing component. The first receiving component is used to receive a first optical signal sent by the first type of ONU in a first time slot group, and the second receiving component is used to receive a second optical signal sent by the second type of ONU in a second time slot group. The first time slot group includes at least one time slot, and the second time slot group includes at least one time slot. The processing component is used to ensure that the first time slot group and the second time slot group do not overlap in the time dimension through a first time slot scheduling mechanism.

[0008] In the present application, the processing component uses a first time slot scheduling mechanism to prevent the first time slot group and the second time slot group from overlapping in the time dimension. That is, the first optical signal and the second optical signal sent by the first type ONU and the second type ONU with overlapping upstream wavelengths are separated in the time dimension through the first time slot scheduling mechanism and do not affect each other, thereby avoiding conflicts in the upstream data sent by the first type ONU and the second type ONU, so that the PON system can work normally.

[0009] In a first possible implementation manner, the plurality of ONUs further include a third type of ONU, and a MAC protocol supported by the third type of ONU is different from the MAC protocol supported by the first type of ONU and the MAC protocol supported by the second type of ONU.

[0010] The upstream wavelengths used by ONUs of the same type may be different. Here, different upstream wavelengths may refer to different central wavelengths and / or wavelength ranges of the upstream wavelengths. ONUs of the same type can be further classified according to the upstream wavelengths used.

[0011] In some examples, the third category ONU can be divided into a first subcategory ONU, a second subcategory ONU, and a third subcategory ONU. The first category ONU can be divided into a fourth subcategory ONU and a fifth subcategory ONU. The upstream wavelength of the first subcategory ONU, the upstream wavelength of the second subcategory ONU, and the upstream wavelength of the second category ONU do not overlap. The upstream wavelength of the first subcategory ONU and the upstream wavelength of the second subcategory ONU both overlap with the upstream wavelength of the third subcategory ONU. The upstream wavelength of the fourth subcategory ONU is consistent with the upstream wavelength of the first subcategory ONU, and the upstream wavelength of the fifth subcategory ONU is consistent with the upstream wavelength of the third subcategory ONU.

[0012] For example, the upstream wavelength of the first subclass ONU is 1290nm-1330nm, the upstream wavelength of the second subclass ONU is 1260nm-1280nm, and the upstream wavelength of the third subclass ONU is 1260nm-1360nm. The upstream wavelength of the fourth subclass ONU is 1290nm-1330nm, and the upstream wavelength of the fifth subclass ONU is 1260nm-1360nm. The upstream wavelength of the second subclass ONU is 1284nm-1288nm.

[0013] In actual applications, the third sub-category ONU is rarely used and may not exist. In this case, the third sub-category ONU includes at least one of the first sub-category ONU and the second sub-category ONU.

[0014] When the third-category ONU includes the first-subcategory ONU and the second-subcategory ONU, that is, when the first-subcategory ONU, the second-subcategory ONU, the fourth-subcategory ONU, the fifth-subcategory ONU, and the second-subcategory ONU coexist in the PON system, the optical communication device further includes a third receiving component. The third receiving component is configured to receive, in the second time slot group, a third optical signal transmitted by the first-subcategory ONU and a fourth optical signal transmitted by the second-subcategory ONU. The third receiving component receives the third and fourth optical signals in the second time slot group simultaneously with the second receiving component receiving the second optical signal via wavelength division multiplexing. The processing component is further configured to, through a second time slot scheduling mechanism, cause the third receiving component to receive, in the second time slot group, the third optical signal transmitted by the first-subcategory ONU and the fourth optical signal transmitted by the second-subcategory ONU in a time division multiplexing manner.

[0015] When the third-category ONU includes the first-subcategory ONU but does not include the second-subcategory ONU, that is, when the first-subcategory ONU, the fourth-subcategory ONU, the fifth-subcategory ONU, and the second-category ONU coexist in the PON system, the optical communication device further includes a third receiving component. The third receiving component is configured to receive a third optical signal transmitted by the first-subcategory ONU in the second time slot group, and the third receiving component receives the third optical signal in the second time slot group simultaneously with the second receiving component receiving the second optical signal through wavelength division multiplexing.

[0016] When the third-category ONU includes the second-subcategory ONU but does not include the first-subcategory ONU, that is, when the second-subcategory ONU, the fourth-subcategory ONU, the fifth-subcategory ONU, and the second-category ONU coexist in the PON system, the optical communication device further includes a third receiving component. The third receiving component is configured to receive a fourth optical signal transmitted by the second-subcategory ONU in the second time slot group, and the third receiving component receives the fourth optical signal in the second time slot group simultaneously with the second receiving component receiving the second optical signal through wavelength division multiplexing.

[0017] Because the upstream wavelength of the first subclass ONU and the upstream wavelength of the second subclass ONU do not overlap with the upstream wavelength of the second subclass ONU, the third optical signal sent by the first subclass ONU and the second optical signal sent by the second subclass ONU can coexist without conflict, and the fourth optical signal sent by the second subclass ONU and the second optical signal sent by the second subclass ONU can coexist without conflict. Therefore, the third receiving component can simultaneously receive the third optical signal and / or the fourth optical signal in the second time slot group and the second receiving component can simultaneously receive the second optical signal through wavelength division multiplexing. This helps improve the upstream bandwidth utilization of the system.

[0018] With the advancement of optical communication technology and the increase in transmission rates, ONUs typically use a narrower range of upstream wavelengths to transmit upstream data. ONUs using a wider range of upstream wavelengths are prioritized for exiting the PON system, enabling PON system upgrades. Therefore, sub-category 5 ONUs are prioritized for exiting the PON system.

[0019] In this case, the first category ONU includes the fourth subcategory ONU but does not include the fifth subcategory ONU. The second receiving component is further configured to receive the second optical signal sent by the second category ONU in the first time slot group and the second time slot group. The third receiving component is further configured to receive the fifth optical signal sent by the fourth subcategory ONU in the first time slot group, and to receive the third optical signal sent by the first subcategory ONU and / or the fourth optical signal sent by the second subcategory ONU in the second time slot group.

[0020] Optionally, the first-class ONU may further include a third-subclass ONU, i.e., a third-subclass ONU is also present in the PON system. Because the uplink wavelength of the third-subclass ONU is consistent with the uplink wavelength of the fifth-subclass ONU, the uplink wavelength of the third-subclass ONU also conflicts with the wavelengths of other ONUs and needs to exit the PON system. Before the third-subclass ONU exits the network, the optical signal transmitted by the third-subclass ONU is received by the first receiving component. That is, when the first-class ONU also includes the third-subclass ONU, the first receiving component is further configured to receive, in a first time slot group, the first optical signal transmitted by the first-class ONU and the sixth optical signal transmitted by the third-subclass ONU in a time division multiplexing manner.

[0021] In the present application, the MAC protocols supported by the first and third category ONUs belong to the same standard system and have similar scheduling methods, so they can be scheduled through the same MAC module. The MAC protocols supported by the second category ONUs belong to different standard systems than the MAC protocols supported by the first category ONUs. Therefore, the second category ONUs are scheduled through a different MAC module. Therefore, the processing component may include a first MAC module and a second MAC module. The first MAC module is used to schedule the first and third category ONUs, and the second MAC module is used to schedule the second category ONUs.

[0022] In the first possible implementation, the optical communication device may adopt any one of the following three structures:

[0023] The first type, the third receiving component includes: a first photoelectric conversion device and a first electrical power splitter. The first photoelectric conversion device is used to convert the third optical signal, the fourth optical signal, and the fifth optical signal into a first electrical signal. The first electrical power splitter is connected to the first photoelectric conversion device and is used to split the first electrical signal into two sub-signals. The first MAC module includes a first single-rate burst clock and data recovery (BCDR) circuit and a second single-rate BCDR circuit. The first single-rate BCDR circuit and the second single-rate BCDR circuit support different rates. The first single-rate BCDR circuit and the second single-rate BCDR circuit are respectively connected to the first electrical power splitter and are respectively used to receive one of the two sub-signals output by the first electrical power splitter at a corresponding rate. The first MAC module selectively receives data of different rates recovered by the first single-rate BCDR circuit and the second single-rate BCDR circuit based on scheduling information of a second time slot scheduling mechanism.

[0024] Second, the third receiving component includes a second photoelectric conversion device. The second photoelectric conversion device is used to convert the third optical signal, the fourth optical signal, and the fifth optical signal into a second electrical signal. The first MAC module includes a dual-rate BCDR circuit, which is connected to the second photoelectric conversion device and is used to selectively receive the second electrical signal at the first rate and / or the second rate. The first MAC module selectively receives data of different rates recovered by the dual-rate BCDR circuit based on scheduling information of the second time slot scheduling mechanism.

[0025] The third receiving component includes a third photoelectric conversion device and a fourth photoelectric conversion device. The third photoelectric conversion device is used to convert the fourth optical signal into a third electrical signal. The fourth photoelectric conversion device is used to convert the third optical signal and the fifth optical signal into a fourth electrical signal. The first MAC module includes a first single-rate BCDR circuit and a dual-rate BCDR circuit. The first single-rate BCDR circuit is connected to the fourth photoelectric converter and is used to receive the fourth electrical signal at a first rate. The dual-rate BCDR circuit is connected to the third photoelectric conversion device and is used to selectively receive the third electrical signal at the first rate or the second rate. The first MAC module is used to receive data of different rates recovered by the first single-rate BCDR circuit and the dual-rate BCDR circuit according to the scheduling information of the first time slot scheduling mechanism and the second time slot scheduling mechanism.

[0026] Optionally, in the third structure above, the third photoelectric conversion device and the fourth photoelectric conversion device may be packaged in the same coaxial tube package, or may be packaged in separate coaxial tube packages.

[0027] For the first or second structure, before the fifth subclass ONU is disconnected from the network, the first MAC module is used to obtain, in the first time slot group, the uplink data sent by the first subclass ONU based on the electrical signal output by the first receiving component; and in the second time slot group, obtain the uplink data sent by the first subclass ONU and the second subclass ONU based on the electrical signal output by the third receiving component. Alternatively, after the fifth subclass ONU is disconnected from the network, the first MAC module is used to obtain, in the first time slot group, the uplink data sent by the fourth subclass ONU based on the electrical signal output by the third receiving component; and in the second time slot group, obtain the uplink data sent by the first subclass ONU and the second subclass ONU based on the electrical signal output by the third receiving component.

[0028] For the third structure, before the fifth subclass ONU is disconnected from the network, the first MAC module is used to obtain the uplink data sent by the first subclass ONU based on the electrical signal output by the first receiving component in the first time slot group; obtain the uplink data sent by the asymmetric ONUs in the first subclass ONU and the second subclass ONU based on the electrical signal output by the first receiving component in the second time slot group; and obtain the uplink data sent by the symmetric ONUs in the second subclass ONU based on the electrical signal output by the third optoelectronic conversion device in the second time slot group. Alternatively, after the fifth subclass ONU is disconnected from the network, the first MAC module is used to obtain the uplink data sent by the second subclass ONU based on the electrical signal output by the third optoelectronic conversion device in the first time slot group and the second time slot group; and obtain the uplink data sent by the first subclass ONU and the uplink data sent by the fourth subclass ONU based on the electrical signal output by the fourth optoelectronic conversion device.

[0029] In a second possible implementation, the plurality of ONUs further include a third type of ONU, wherein the MAC protocol supported by the third type of ONU is different from the MAC protocol supported by the first type of ONU and the MAC protocol supported by the second type of ONU, and the upstream wavelength of the third type of ONU overlaps with the upstream wavelength of the first type of ONU. The first receiving component is further configured to receive a third optical signal transmitted by the third type of ONU in the first time slot group. The processing component is further configured to enable the first receiving component to receive the first optical signal and the third optical signal in the first time slot group in a time division multiplexing manner through a third time slot scheduling mechanism.

[0030] In this embodiment, the processing component uses the third time slot scheduling mechanism to enable time division multiplexing of the first type ONU and the third type ONU within the first time slot group. In this way, conflicts in the upstream data sent by the first type ONU and the third type ONU with overlapping upstream wavelengths can be avoided, thereby enabling the coexistence of the first type ONU, the second type ONU and the third type ONU in the PON system.

[0031] In some examples, the first receiving component includes a fifth photoelectric conversion device and a second electrical power splitter. The fifth photoelectric conversion device is configured to convert the first optical signal and the third optical signal into a fifth electrical signal. The second electrical power splitter is connected to the fifth photoelectric conversion device and is configured to split the fifth electrical signal into two sub-signals. The processing component includes a first MAC module. The first MAC module includes a first single-rate BCDR circuit and a second single-rate BCDR circuit. The first and second single-rate BCDR circuits support different rates. The first and second single-rate BCDR circuits are respectively connected to the second electrical power splitter and are respectively configured to receive one of the two sub-signals output by the second electrical power splitter at a corresponding rate. The first MAC module is configured to selectively receive data of different rates recovered by the first and second single-rate BCDR circuits based on scheduling information of the third time slot scheduling mechanism.

[0032] For the first MAC module, two single-speed BCDR circuits are used to correspond to the uplink transmission rate of the first type of ONU and the uplink transmission rate of the third type of ONU, which is beneficial to reducing the cost of the optical communication device.

[0033] In other examples, the first receiving component includes a sixth photoelectric conversion device. The sixth photoelectric conversion device is configured to convert the first optical signal and the third optical signal into a fifth electrical signal. The processing component includes a first MAC module, the first MAC module including a dual-rate BCDR circuit, the dual-rate BCDR circuit being connected to the sixth photoelectric conversion device and configured to selectively receive the fifth electrical signal at the first rate and / or the second rate. The first MAC module is configured to selectively receive data of different rates recovered by the dual-rate BCDR circuit based on scheduling information of the third time slot scheduling mechanism.

[0034] By using a dual-speed BCDR to correspond to the uplink transmission rates of the first type ONU and the third type ONU respectively, the number of components included in the first receiving component can be reduced, thereby simplifying the structure of the first receiving component.

[0035] In the first possible implementation, the MAC protocol supported by the first MAC module belongs to the same standard system as the MAC protocol supported by the first and third type ONUs. Therefore, the first and third type ONUs can be uniformly scheduled and uplink data sent by the first and third type ONUs can be received.

[0036] Optionally, the processing component further includes: a second MAC module connected to the first MAC module, wherein the second MAC module synchronizes bandwidth allocation information with the first MAC module to implement the function of the first time slot scheduling mechanism.

[0037] By connecting the second MAC module to the second MAC module, the bandwidth allocation information can be synchronized between the first MAC module and the second MAC module, thereby realizing the function of the first time slot scheduling mechanism.

[0038] Optionally, the processing component employs a first time slot scheduling mechanism as follows: determining a first time slot group and a second time slot group in a target period based on information related to bandwidth requirements of the plurality of ONUs, wherein the target period includes M time slots, where M is greater than 1 and is an integer, the first time slot group includes X time slots of the M time slots, and the second time slot group includes Y time slots of the M time slots, where X and Y are both positive integers, and the sum of X and Y is less than or equal to M. The time slots of the first time slot group are allocated to the first type of ONUs according to a MAC protocol supported by the first type of ONUs, and the time slots of the second time slot group are allocated to the second type of ONUs according to a MAC protocol supported by the second type of ONUs.

[0039] Hereinafter, the time slots in the first time slot group are referred to as first time slots, and the time slots in the second time slot group are referred to as second time slots.

[0040] In one possible embodiment, the first time slot group includes at least two first subsets, any one of the at least two first subsets includes one first time slot or includes at least two consecutive first time slots, and there is at least one second time slot between two adjacent first subsets in the at least two first subsets; and / or, the second time slot group includes at least two second subsets, any one of the at least two second subsets includes one second time slot or includes at least two consecutive time slots, and there is at least one first time slot between two adjacent second subsets in the at least two second subsets.

[0041] In another possible implementation, the first time slot group includes one first time slot or at least two consecutive first time slots; and / or the second time slot group includes one second time slot or at least two consecutive second time slots.

[0042] Optionally, at least one first time slot in the first time slot group is a windowed time slot; and / or at least one second time slot in the second time slot group is a windowed time slot.

[0043] Optionally, the first time slot scheduling mechanism further includes: using a time slot outside the target period or at least two consecutive time slots as windowed time slots.

[0044] Optionally, the information related to the bandwidth requirement of the ONU includes at least one of the number of each type of ONUs and service information of services enabled by the ONU. Optionally, the service information includes service type or latency requirement.

[0045] In this application, the first time slot group is used to schedule ONUs in the first terminal set, and the second time slot group is used to schedule ONUs in the second terminal set. The greater the number of ONUs in the first terminal set and the greater the bandwidth demand corresponding to the services activated by each ONU, the greater the proportion of time slots included in the first time slot group in the target period. Similarly, the greater the number of ONUs in the second terminal set and the greater the bandwidth demand corresponding to the services activated by each ONU, the greater the proportion of time slots included in the second time slot group in the target period.

[0046] In some examples, the first terminal set includes first-category ONUs, and the second terminal set includes second-category ONUs; or, the first terminal set includes first-category ONUs and third-category ONUs, and the second terminal set includes second-category ONUs.

[0047] In some examples, the receiving wavelength range of the first receiving component is 1260 nm-X nm, where X is less than or equal to 1360 and greater than 1330.

[0048] In actual network deployment, this optical communication device is typically part of the OLT, which is connected to multiple ONUs via the optical network device (ODN). If there is reflection on the ODN and the receiving wavelength range of the first receiving component overlaps with the downstream wavelength of the second-type ONU, the downstream optical signal of the second-type ONU may be reflected back to the OLT by the ODN and enter the first receiving component. This can affect the reception and data recovery of upstream signals by the first-type and third-type ONUs. To mitigate this risk, the receiving wavelength range of the first receiving component can be set to not overlap with the downstream wavelength of the second-type ONU. For example, when the downstream wavelength of the second-type ONU is 1340nm-1344nm, X can be set to less than or equal to 1340. At the same time, to avoid affecting the normal reception of the third optical signal sent by the first-subtype ONU and the fifth optical signal sent by the fourth-subtype ONU, X needs to be greater than 1330.

[0049] For example, the MAC protocol supported by the first type of ONU is the EPON protocol, the MAC protocol supported by the second type of ONU is the 50G PON protocol, and the MAC protocol supported by the third type of ONU is the 10G EPON protocol.

[0050] When the second type of ONU is a 50G PON ONU, that is, when the MAC protocol supported by the second type of ONU is the 50G PON protocol, since the corresponding MAC protocol stipulates a strict 125μs superframe structure and superframe synchronization, in an embodiment of the present application, the length of a single time slot in the first time slot group and the second time slot group is an integer multiple of 125μs, so that the time slots in the second time slot group can meet the requirements of the MAC protocol, and the time slots in the first time slot group can also be aligned and synchronized.

[0051] In some examples, the length of a single time slot in the first time slot group is M times 125 μs, and the length of a single time slot in the second time slot group is N times 125 μs. Optionally, M is equal to N, which simplifies the first time slot scheduling mechanism. Alternatively, M may not be equal to N. The values ​​of M and N can be determined based on actual needs, for example, 1, 2, or 3.

[0052] Optionally, the optical communication device further includes a sending component configured to send optical signals to the first type ONU, the second type ONU, and the third type ONU.

[0053] In a second aspect, the present application further provides an optical communication system, which includes an OLT and multiple ONUs, wherein the OLT includes any of the aforementioned optical communication devices.

[0054] In a third aspect, the present application further provides a communication method. The method is configured to receive optical signals transmitted by multiple ONUs using multiple receiving components, wherein the multiple receiving components include a first receiving component, a second receiving component, and a third receiving component. For details regarding the first, second, and third types of ONUs, as well as the first, second, and third receiving components, see the first aspect.

[0055] In one possible embodiment, the method includes: in a first stage, in the first time slot group, obtaining the uplink data sent by the first type ONU based on the electrical signal output by the first receiving component, in the second time slot group, obtaining the uplink data sent by the second type ONU based on the electrical signal output by the second receiving component, and in the second time slot group, obtaining the uplink data sent by the first subclass ONU and the second subclass ONU based on the electrical signal output by the third receiving component; or, in a second stage, in the first time slot group and the second time slot group, obtaining the uplink data sent by the second type ONU based on the electrical signal output by the second receiving component, in the first time slot group, obtaining the uplink data sent by the fourth subclass ONU based on the electrical signal output by the third receiving component, and in the second time slot group, obtaining the uplink data sent by the first subclass ONU and the second subclass ONU based on the electrical signal output by the third receiving component.

[0056] In another possible embodiment, the method includes: in a first phase, obtaining, based on the electrical signal output by the first receiving component in a first time slot group, upstream data sent by the first type ONU and the first subtype ONU; in a second time slot group, obtaining, based on the electrical signal output by the second receiving component, upstream data sent by the second type ONU; and in a second time slot group, obtaining, based on the electrical signal output by the third photoelectric conversion device in the third receiving component, upstream data sent by the second subtype ONU; or, in a second phase, obtaining, based on the electrical signal output by the second receiving component, upstream data sent by the second type ONU; and, simultaneously, receiving, based on the third receiving component, upstream data sent by the second subtype ONU, upstream data sent by the fourth subtype ONU, and upstream data sent by the first subtype ONU. The upstream data sent by the second subtype ONU is obtained via the electrical signal output by the third photoelectric conversion device, and the upstream data sent by the fourth subtype ONU and upstream data sent by the first subtype ONU are obtained via the electrical signal output by the fourth photoelectric conversion device.

[0057] In the first phase, the PON system contains all the first, second, and third category ONUs, and the first category ONUs include the fourth and fifth subcategory ONUs. In the second phase, the fifth subcategory ONUs of the first category ONUs and the third subcategory ONUs of the third category ONUs have been decommissioned, or the fifth subcategory ONUs of the first category ONUs and the third subcategory ONUs of the third category ONUs have been upgraded to the second category ONUs, the first subcategory ONUs, or the second subcategory ONUs. That is, the fifth subcategory ONUs and the third subcategory ONUs no longer exist in the PON system.

[0058] By selecting the corresponding receiving component to receive upstream data from the ONU at different stages, the OLT with the same hardware structure can communicate with the existing ONUs in the PON system before and after the PON system upgrade. The OLT hardware structure does not need to be changed before and after the PON system upgrade, which helps reduce costs.

[0059] In a fourth aspect, the present application provides a communication method applied to a passive optical network (PON) system, wherein the PON system includes an optical line terminal (OLT) and at least one optical network unit (ONU), the method comprising:

[0060] The ONU receives a first downstream physical frame sent by the OLT, the first downstream physical frame including an index of an available downstream wavelength channel of the PON system; then, the ONU determines whether the downstream wavelength channel corresponding to the index of the downstream wavelength channel is available. If the ONU determines that the downstream wavelength channel corresponding to the index of the downstream wavelength channel is available, the ONU further receives a second downstream physical frame sent by the OLT on the downstream wavelength channel.

[0061] In the communication method provided in the present application, since the OLT can notify the ONU of the available downstream wavelength channels of the current PON system through the downstream wavelength channel index in the first downstream physical frame, communication conflicts caused by downstream wavelength mismatch between the OLT and the ONU are avoided, thereby improving communication efficiency.

[0062] In one possible solution, the communication method provided herein is used in a time- and wavelength-division multiplexing (TWDM) PON system. In a TWDM PON system, the downstream direction of the OLT uses wavelength division multiplexing, and the downstream channel is wavelength-division multiplexed into multiple downstream wavelength channels. The multiple downstream wavelength channels do not interfere with each other.

[0063] In one possible solution, the communication method provided by this application includes:

[0064] The ONU receives a first downstream physical frame sent by the OLT, where the first downstream physical frame includes an index of a downstream wavelength channel available in the PON system; the ONU determines whether a downstream wavelength channel corresponding to the index of the downstream wavelength channel is available; if the ONU determines that the downstream wavelength channel corresponding to the index of the downstream wavelength channel is available for activation, the ONU enters a sequence number state of an activation process.

[0065] In one possible solution, if the ONU determines that the downstream wavelength channel corresponding to the downstream wavelength channel index is unavailable, it searches for other available downstream wavelength channels and enters an asynchronous state in the activation process. In the asynchronous state, the ONU retains system and channel mode information but discards burst mode information.

[0066] The ONU can tune its receiver to search for other available downstream wavelength channels.

[0067] In the solution provided in the fourth aspect, the ONU determines whether the downstream wavelength channel corresponding to the downstream wavelength channel index is available for activation. If so, the ONU further receives a second downstream physical frame sent by the OLT on the downstream wavelength channel. If not, the ONU searches for other available downstream wavelength channels.

[0068] In a possible solution, the ONU receives a first downstream physical frame sent by the OLT in a mode learning state in an activation process, where the first downstream physical frame includes an index of a downstream wavelength channel available in the PON system.

[0069] In one possible solution, the operation control body of the first downlink physical frame carries the index of the downlink wavelength channel. Furthermore, the operation control body of the downlink physical synchronization block of the downlink physical frame carries the index of the downlink wavelength channel.

[0070] The ONU determining whether the downstream wavelength corresponding to the index of the downstream wavelength channel is available includes: the ONU determining whether the downstream wavelength channel corresponding to the index of the downstream wavelength channel included in the operation control body part of the first downstream physical frame is available for activation.

[0071] The index of the downlink wavelength channel occupies at least 2 bits, for example, 3 bits, in the operation control subject field.

[0072] In one possible solution, when the ONU determines that the downstream wavelength channel corresponding to the index of the downstream wavelength channel is available, the step of receiving the second downstream physical frame sent by the OLT on the downstream wavelength channel can be replaced by: when the ONU determines that the downstream wavelength channel corresponding to the index of the downstream wavelength channel is available for activation, the ONU enters the sequence number state of the activation process.

[0073] In the serial number state, the ONU can start its transmitter and tune it to the upstream wavelength channel. Subsequently, after receiving the serial number grant message sent by the OLT, the ONU sends its own serial number to the OLT on the upstream wavelength channel.

[0074] When the ONU sends its own serial number to the OLT, if the ONU supports power balancing, the ONU may perform ONU-activated power balancing to save power consumption.

[0075] In one possible solution, when the ONU searches for an available downstream wavelength channel, the ONU enters an asynchronous state. If the ONU does not search for an available downstream wavelength channel, the ONU enters an initial state. In the initial state, the ONU performs a downstream channel scan.

[0076] In one possible solution, the OLT can send an assigned ONU ID to the ONT to identify the ONU. The OLT can also send a ranging request message to the ONU. After receiving the ranging request message, the ONU returns a ranging response message to the OLT. The OLT calculates the equalization parameters corresponding to the ONU based on the ranging response message and then sends a ranging time message to the ONU, which carries the equalization delay for the ONU. After receiving the equalization delay, the ONU can enter the operational state (completing the activation process).

[0077] In the operating state, the ONU can process the second downstream physical frame received on the downstream wavelength channel and obtain user data carried in the second downstream physical frame.

[0078] In one possible solution, the ONU receives a wavelength adjustment message sent by the OLT, tunes its transmitter to a target upstream wavelength channel according to the wavelength adjustment message, and then sends an upstream message to the OLT through the target upstream wavelength channel to complete the activation process.

[0079] In the solution provided in the present application, other downlink physical frames may be spaced between the first downlink physical frame and the second downlink physical frame, and the downlink message sent by the OLT to the ONT may be carried by the downlink physical frame.

[0080] In a fifth aspect, the present application provides a communication method applied to a passive optical network (PON) system, wherein the PON system includes an optical line terminal (OLT) and at least one optical network unit (ONU), the method comprising:

[0081] The OLT sends a first downstream physical frame to the ONU, where the first downstream physical frame includes an index of a downstream wavelength channel available in the PON system; the OLT sends a second downstream physical frame to the ONU on the downstream wavelength channel corresponding to the index of the downstream wavelength channel.

[0082] The communication method provided in this application can be applied to a time division multiplexing (TWDM) PON system, and the transmission rate of the TWDM PON system can include 10G, 50G, 100G, 200G or higher. In the TWDM PON system, the downstream direction of the OLT (the direction from the OLT to the ONU) adopts wavelength division multiplexing, and the downstream channel wavelength division multiplexing is multiplexed into multiple downstream wavelength channels. The multiple downstream wavelength channels do not interfere with each other. By sending the index of the downstream wavelength channel to the ONU, the OLT can enable the ONU to determine the downstream wavelength channel that can be used for activation based on the index, and then the ONU performs the activation process on the determined downstream wavelength channel, thereby avoiding the downstream wavelength channel conflict between the OLT and the ONU.

[0083] Similar to the fourth aspect, the OLT may include the index of the downstream wavelength channel in the operation control body field of the first downstream physical frame.

[0084] The index of the downstream wavelength channel occupies at least 2 bits in the operation control subject field. For example, the index of the downstream wavelength channel occupies 3 bits.

[0085] The first downlink physical frame and the second downlink physical frame may be separated by other downlink physical frames, and the downlink message sent by the OLT to the ONT may be carried by the downlink physical frame.

[0086] In the communication method provided in the fifth aspect, when the ONU determines that the downstream wavelength channel corresponding to the index of the downstream wavelength channel is available for activation, the ONU enters the sequence number state of the activation process. In the sequence number state, the OLT may send a sequence number grant message to the ONU. After receiving the sequence number grant message from the OLT, the ONU sends its own sequence number to the OLT on the upstream wavelength channel.

[0087] When the OLT receives the serial number sent by the ONU, it determines that the ONU is a newly connected ONU and sends the assigned ONU ID to the ONU. In addition, the OLT can also send a wavelength adjustment message or a wavelength calibration message to the ONU so that the ONU can tune its transmitter to the target upstream wavelength channel to communicate with the OLT.

[0088] In one possible solution, the OLT can also send a ranging request message to the ONU. After receiving the ranging request message, the ONU returns a ranging response message to the OLT. The OLT calculates the equalization parameters corresponding to the ONU based on the ranging response message and then sends a ranging time message to the ONU, which contains the equalization delay for the ONU. After receiving the equalization delay, the ONU can enter the operational state (completing the activation process).

[0089] In a sixth aspect, the present application also provides an optical communication device, comprising a processor and a memory, wherein the memory is used to store a software program, and the processor runs or executes the software program stored in the memory to enable the optical communication device to perform the communication method performed by the ONU in the fourth aspect, or to enable the optical communication device to perform the communication method performed by the OLT in the fifth aspect.

[0090] The optical communication device provided by this aspect can be used as an optical line terminal or an optical network unit device.

[0091] In the seventh aspect, the present application provides a computer-readable storage medium, which is used to store program codes executed by a processor, and the program codes include instructions for implementing the communication method in any possible implementation of the fourth or fifth aspect above.

[0092] In an eighth aspect, the present application provides a chip comprising a processor, the processor being used to call and execute instructions stored in a memory from the memory, so that an optical communication device equipped with the chip executes a communication method in any possible implementation of the fourth or fifth aspect above. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] FIG1 is a schematic structural diagram of a PON system provided in an embodiment of the present application;

[0094] FIG2 is a schematic structural diagram of an optical communication device provided in an embodiment of the present application;

[0095] FIG3 is a schematic structural diagram of another optical communication device provided in an embodiment of the present application;

[0096] FIG4 is a schematic diagram of a time slot allocation method provided in an embodiment of the present application;

[0097] FIG5 is a schematic structural diagram of another optical communication device provided in an embodiment of the present application;

[0098] FIG6 is a schematic structural diagram of another optical communication device provided in an embodiment of the present application;

[0099] FIG7 is a schematic structural diagram of another optical communication device provided in an embodiment of the present application;

[0100] FIG8 is a schematic diagram of another time slot allocation method provided in an embodiment of the present application;

[0101] FIG9 is a schematic structural diagram of another optical communication device provided in an embodiment of the present application;

[0102] FIG10 is a schematic diagram of a time slot allocation method provided in an embodiment of the present application;

[0103] FIG11 is a schematic structural diagram of another optical communication device provided in an embodiment of the present application;

[0104] FIG12 is a flow chart of an optical communication method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0105] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0106] Figure 1 is a schematic diagram of a PON system provided in an embodiment of the present application. As shown in Figure 1, the PON system includes an OLT 110, an ONU device 120, and an ODN 130. The OLT 110 is connected to one or more ONUs 120 via the ODN 130. The ONU 120 may also be referred to as an optical network terminal (ONT).

[0107] OLT 110 is typically located on the network side, such as a central office (CO), and can centrally manage multiple ONUs 120. OLT 110 can act as an intermediary between ONUs 120 and an upper-layer network (not shown), forwarding data received from the upper-layer network to ONUs 120 and vice versa. Upper-layer networks include, but are not limited to, the Internet, the public switched telephone network (PSTN), and community antenna television (CATV).

[0108] Multiple ONUs 120 can be distributed and arranged at the user side. ONUs 120 can be network devices that communicate with OLT 110 and user devices. ONUs 120 can act as an intermediary between OLT 110 and user devices. For example, ONUs 120 can forward data received from OLT 110 to user devices, and forward data received from user devices to OLT 110.

[0109] ODN 130 is a data distribution / multiplexing system that can include trunk optical fibers, passive optical splitters, and user optical fibers. The passive optical splitters can include a first port and multiple second ports. The first port of the passive optical splitter is connected to OLT 110 via the trunk optical fiber, and each second port of the passive optical splitter is connected to an ONU 120 via a user optical fiber.

[0110] In a PON system, data transmission from the OLT 110 to the ONUs 120 is considered downstream. The OLT 110 broadcasts downstream data to all ONUs 120, and each ONU 120 only receives data with its own identifier. Conversely, data transmission from the ONUs 120 to the OLT 110 is considered upstream. Because each ONU 120 shares the ODN 130 and OLT 110, to prevent conflicts between upstream data from each ONU 120, the PON system uses time division multiplexing (TDM) or time and wavelength division multiplexing (TWDM) to transmit upstream data. Specifically, the OLT 110 allocates upstream time slots to each ONU 120, and each ONU 120 transmits upstream data according to the upstream time slots assigned by the OLT 110.

[0111] In the embodiment of the present application, there are at least two types of ONUs 120, and the different types of ONUs support different MAC protocols. Optionally, the MAC protocol includes but is not limited to the GPON protocol, EPON protocol, 10G PON protocol, 10G EPON protocol, or a MAC protocol with a higher transmission rate such as the 40G PON protocol, 50G PON protocol, or 100G PON protocol.

[0112] For example, among Fig. 1, a plurality of ONUs 120 at least comprise a first type ONU 120a, a second type ONU 120b and a third type ONU 120c. The MAC protocols that the first type ONU 120a, the second type ONU 120b and the third type ONU 120c support are different. In other embodiments, a plurality of ONUs 120 may also only comprise the first type ONU 120a and the second type ONU 120b, or may comprise more types of ONUs.

[0113] The MAC protocols supported by different types of ONUs may belong to the same standard system or different standard systems. Here, the standard system includes but is not limited to the Institute of Electrical and Electronics Engineers (IEEE) standard system and the International Telecommunication Union-Telecommunication Standardization Sector (ITU-T) standard system.

[0114] In some examples, the MAC protocol supported by the third type ONU and the MAC protocol supported by the first type ONU belong to the same standard system, for example, both belong to the IEEE standard system. In some examples, the MAC protocol supported by the second type ONU and the MAC protocol supported by the first type ONU belong to different standard systems, for example, the MAC protocol supported by the first type ONU belongs to the IEEE standard system, while the MAC protocol supported by the second type ONU belongs to the ITU-T standard system.

[0115] The upstream wavelengths of different types of ONUs may or may not overlap. The following examples illustrate this using the following examples: Type 1 ONUs support EPON as the MAC protocol, Type 2 ONUs support 10G EPON as the MAC protocol, and Type 3 ONUs support 50G PON as the MAC protocol. Exemplarily, the upstream wavelength of the first type ONU 120a includes 1260nm-1360nm or 1290nm-1330nm; the upstream wavelength of the second type ONU 120b is 1284nm-1288nm, which overlaps with the upstream wavelength 1260nm-1360nm of the first type ONU 120a; the upstream wavelength of the third type ONU 120c includes 1260nm-1360nm, 1290nm-1330nm or 1260nm-1280nm, then the upstream wavelength 1260nm-1360nm of the third type ONU 120c overlaps with the upstream wavelength of the second type ONU 120b, while the upstream wavelengths 1290nm-1330nm and 1260nm-1280nm of the third type ONU 120c do not overlap with the upstream wavelength of the second type ONU 120b.

[0116] For the same type of ONU, when the ONU uses different laser types, the corresponding upstream wavelength may also be different. Here, different upstream wavelengths refer to different center wavelengths and / or upstream wavelength coverage (or bandwidth). For example, when the ONU is an EPON ONU, if the ONU uses a distributed feedback (DFB) laser, the corresponding upstream wavelength is 1290nm-1330nm; if the ONU uses a Fabry-Perot (FP) laser, the corresponding upstream wavelength is 1260nm-1360nm. For another example, when the ONU is an asymmetric 10G EPON ONU, if the ONU uses a DFB laser, the corresponding upstream wavelength is 1290nm-1330nm or 1260nm-1280nm; if the ONU uses an FP laser, the corresponding upstream wavelength is 1260nm-1360nm. For another example, when the ONU is a symmetrical 10G EPON ONU, the ONU generally uses a DFB laser, and the corresponding upstream wavelength is 1260 nm-1280 nm.

[0117] For ONUs with the widest upstream wavelength coverage, those using FP lasers, their upstream wavelengths overlap with those of other ONUs. Furthermore, because ONUs using FP lasers have lower transmission rates, they are prioritized for exiting the PON system, enabling PON system upgrades. However, due to the large number of ONUs using FP lasers, it is difficult to fully exit the PON system in a short period of time. Therefore, the coexistence of these ONUs with other ONUs must be considered. Once these ONUs have exited the PON system, the coexistence of the remaining ONUs must be considered. In other words, the coexistence of multiple ONUs supporting different MAC protocols and with overlapping upstream wavelengths must be ensured within the PON system.

[0118] To ensure the normal operation of a PON system, embodiments of the present application provide an optical communication device. This optical communication device can schedule these ONUs using time division multiplexing (TDM) or a combination of TDM and WDM to avoid conflicts in upstream data sent by ONUs with overlapping upstream wavelengths. This optical communication device can be an OLT or a portion of an OLT.

[0119] The optical communication device provided in the embodiments of the present application is described in detail below.

[0120] Figure 2 is a schematic diagram of the structure of an optical communication device provided in an embodiment of the present application. As shown in Figure 2, the optical communication device 1 includes: a first receiving component 11, a second receiving component 12, and a processing component 20. The first receiving component 11 is used to receive a first optical signal sent by a first type of ONU in a first time slot group, and the second receiving component 12 is used to receive a second optical signal sent by a second type of ONU in a second time slot group, wherein the first type of ONU and the second type of ONU support different MAC protocols, and the upstream wavelengths of the first type of ONU and the second type of ONU overlap. The first time slot group includes at least one time slot, and the second time slot group includes at least one time slot. The processing component 20 is used to make the first time slot group and the second time slot group non-overlap in the time dimension through a first time slot scheduling mechanism.

[0121] Optionally, the optical communication device may further include a sending component 30, wherein the sending component 30 is configured to send optical signals to the first type ONU and the second type ONU.

[0122] In practical applications, the first receiving component 11, the second receiving component 12, and the transmitting component 30 can be integrated into an optical module. Because the optical module has multiple receiving components corresponding to different wavelengths, it can be called a combo optical module. The processing component 20 can be provided on a single board, which is connected to the combo optical module.

[0123] In this embodiment of the present application, the first time slot scheduling mechanism is used to group time slots to obtain a first time slot group and a second time slot group. The time slots of the first time slot group are used to schedule the first type of ONU, so that the first type of ONU transmits the first optical signal in the time slots of the first time slot group. The time slots of the second time slot group are used to schedule the second type of ONU, so that the second type of ONU transmits the second optical signal in the time slots of the second time slot group.

[0124] The first time slot scheduling mechanism prevents the first time slot group and the second time slot group from overlapping in the time dimension. For first-type ONUs and second-type ONUs with overlapping upstream wavelengths, the first time slot scheduling mechanism can stagger the first optical signal sent by the first-type ONU and the second optical signal sent by the second-type ONU in the time dimension so that they do not affect each other. This avoids conflicts in upstream data sent by the first-type ONU and the second-type ONU, enabling the normal operation of the PON system.

[0125] When the protocols supported by the first type ONU and the second type ONU belong to different standard systems, the processing component 20 may include a first MAC module and a second MAC module, wherein the first MAC module and the MAC protocol supported by the first type ONU belong to the same standard system, and the second MAC module and the MAC protocol supported by the second type ONU belong to the same standard system.

[0126] The first MAC module is connected to the second MAC module, and the first MAC module and the second MAC module synchronize bandwidth allocation information to implement the function of the aforementioned first time slot scheduling mechanism. Here, the bandwidth allocation information is used to at least indicate the time slots included in the first time slot group and the time slots included in the second time slot group.

[0127] In some examples, the first MAC module can implement the function of the first time slot scheduling mechanism and then synchronize the bandwidth allocation information determined based on the first time slot scheduling mechanism to the second MAC module; or, the second MAC module can implement the function of the first time slot scheduling mechanism and then synchronize the bandwidth allocation information determined based on the first time slot scheduling mechanism to the first MAC module.

[0128] For example, the first type of ONU may be an EPON ONU, and the second type of ONU may be a 50G PON ONU. When the second type of ONU is a 50G PON ONU, since the corresponding MAC protocol specifies a strict 125μs superframe structure and superframe synchronization, in an embodiment of the present application, the time slot lengths of the first time slot group and the second time slot group are both integer multiples of 125μs, so that the time slots in the second time slot group can meet the requirements of the MAC protocol, and the time slots in the first time slot group can also be aligned and synchronized.

[0129] In some examples, the time slot length of the first time slot group is M times 125 μs, and the time slot length of the second time slot group is N times 125 μs. Optionally, M is equal to N, which simplifies the first time slot scheduling mechanism. Alternatively, M may not be equal to N. The values ​​of M and N can be determined based on actual needs, for example, 1, 2, or 3.

[0130] In the embodiment of the present application, the number of time slots included in the first time slot group and the number of time slots included in the second time slot group can be set according to actual needs. The number of time slots included in a single first time slot group and the number of time slots included in a single second time slot group can be equal or different.

[0131] In some examples, in addition to the first and second type ONUs, the PON system also includes a third type ONU. The following describes in detail the structure of an optical communication device for the coexistence of these three types of ONUs. This description uses as an example the MAC protocol supported by the first type ONU as the EPON protocol, the MAC protocol supported by the second type ONU as the 50G PON protocol, and the MAC protocol supported by the third type ONU as the 10G EPON protocol.

[0132] Figure 3 is a schematic diagram of the structure of another optical communication device provided in an embodiment of the present application. The optical communication device is applicable to a PON system including the aforementioned first type ONU, second type ONU, and third type ONU.

[0133] In some examples, the third category ONU includes a first subcategory ONU, a second subcategory ONU, and a third subcategory ONU. The upstream wavelength of the first subcategory ONU does not overlap with the upstream wavelength of the second subcategory ONU, and the upstream wavelength of the first subcategory ONU and the upstream wavelength of the second subcategory ONU both overlap with the upstream wavelength of the third subcategory ONU. For example, the upstream wavelength of the first subcategory ONU is 1290 nm to 1330 nm, the upstream wavelength of the second subcategory ONU is 1260 nm to 1280 nm, and the upstream wavelength of the third subcategory ONU is 1260 nm to 1360 nm.

[0134] The first category of ONUs includes the fourth and fifth subcategory ONUs. The upstream wavelength of the fourth and fifth subcategory ONUs overlaps. The upstream wavelength of the fourth subcategory ONUs is the same as that of the first subcategory ONUs, and the upstream wavelength of the fifth subcategory ONUs is the same as that of the third subcategory ONUs. That is, the upstream wavelength of the fourth subcategory ONUs is 1290 nm to 1330 nm, and the upstream wavelength of the fifth subcategory ONUs is 1260 nm to 1360 nm.

[0135] As mentioned above, the upstream wavelength of the second type ONU is 1284nm-1288nm. Therefore, the upstream wavelength of the first subtype ONU does not overlap with the upstream wavelength of the second type ONU, and the upstream wavelength of the second subtype ONU does not overlap with the upstream wavelength of the second type ONU.

[0136] In other examples, the third category ONU may not include the third subcategory ONU, because the third subcategory ONU is rarely used in actual applications. The following example illustrates the third category ONU including the first subcategory ONU and the second subcategory ONU, but not the third subcategory ONU.

[0137] As shown in Figure 3, the optical communication device includes a first receiving component 11, a second receiving component 12, a third receiving component 13, and a processing component 20. The first receiving component 11 is configured to receive a first optical signal transmitted by a first-type ONU in a first time slot group. The second receiving component 12 is configured to receive a second optical signal transmitted by a second-type ONU in a second time slot group. The third receiving component 13 is configured to receive a third optical signal transmitted by a first-subtype ONU and a fourth optical signal transmitted by a second-subtype ONU in a second time slot group. The third receiving component 13 receives the third and fourth optical signals in the second time slot group simultaneously with the second receiving component 12 receiving the second optical signal via wavelength division multiplexing. For details regarding the first and second time slot groups, see the previous embodiments, and a detailed description thereof will be omitted.

[0138] Exemplarily, when the first type of ONU includes a fourth subtype ONU and a fifth subtype ONU, the first optical signal sent by the first type of ONU includes a fifth optical signal sent by the fourth subtype ONU and a sixth optical signal sent by the fifth subtype ONU.

[0139] In an embodiment of the present application, for a first-class ONU and a second-class ONU with overlapping upstream wavelengths, a first time slot scheduling mechanism can be used to stagger the first optical signal sent by the first-class ONU and the second optical signal sent by the second-class ONU in the time dimension, without affecting each other, thereby avoiding conflicts in the upstream data sent by the first-class ONU and the second-class ONU. Furthermore, because the upstream wavelength of the first subclass ONU and the upstream wavelength of the second subclass ONU in the third-class ONU do not overlap with the upstream wavelength of the second-class ONU, the third optical signal sent by the first subclass ONU and the fourth optical signal sent by the second subclass ONU can be wavelength-division multiplexed with the second optical signal sent by the second-class ONU, and the third optical signal, the fourth optical signal, and the second optical signal are all sent in the second time slot group without interfering with each other. At the same time, the third optical signal sent by the first subclass ONU and the fourth optical signal sent by the second subclass ONU are staggered in the time dimension with the first optical signal sent by the first-class ONU, and also do not affect each other. Therefore, the uplink data sent by the first subclass ONU and the second subclass ONU does not conflict with the uplink data sent by the first class ONU and the second class ONU. The first class ONU, the second class ONU, the first subclass ONU and the second subclass ONU can coexist in the PON system, and the PON system can work normally.

[0140] In addition, the third receiving component 13 receives the third optical signal and the fourth optical signal in the second time slot group and the second receiving component 12 receives the second optical signal simultaneously through wavelength division multiplexing, which is beneficial to improving the uplink bandwidth utilization of the system.

[0141] In the embodiment of the present application, the second subclass ONU may include an asymmetric 10G EPON ONU or a symmetric 10G EPON ONU. That is, the uplink transmission rate of the second subclass ONU may be 1.25 Gbps or 10 Gbps; while the first subclass ONUs are all asymmetric 10G EPON ONUs, and the corresponding uplink transmission rate is 1.25 Gbps. Therefore, the processing component 20 is further configured to cause the third receiving component 13 to receive the third optical signal transmitted by the first subclass ONU and the fourth optical signal transmitted by the second subclass ONU in a time division multiplexing manner in the second time slot group through the second time slot scheduling mechanism.

[0142] Here, the second time slot scheduling mechanism is used to generate scheduling information, which is used to indicate the authorized bandwidth of the first subclass ONU and the authorized bandwidth of the second subclass ONU, and the authorized bandwidth of the first subclass ONU and the second subclass ONU do not overlap in the time dimension. The authorized bandwidth of the second subclass ONU includes a symmetric authorized bandwidth of the second subclass ONU and an asymmetric authorized bandwidth of the second subclass ONU, and the symmetric authorized bandwidth of the second subclass ONU and the asymmetric authorized bandwidth of the second subclass ONU do not overlap in the time dimension.

[0143] In an embodiment of the present application, the first receiving component 11 includes at least a photoelectric conversion device 111 for converting a first optical signal into an electrical signal for output. The first receiving component 11 may also include an LA 112 for amplifying the electrical signal output by the photoelectric conversion device 111. The second receiving component 12 includes at least a photoelectric conversion device 121 for converting the second optical signal into an electrical signal for output. The second receiving component may also include devices such as an LA, which are not shown in the figure. The first receiving component 11 and the second receiving component 12 may also include electrical signal processing devices such as transimpedance amplifiers for amplifying and processing the electrical signal output by the photoelectric conversion device before outputting it to other devices.

[0144] Optionally, the third receiving component 13 includes a first photoelectric conversion device 131a and a first electrical power splitter 132. The first photoelectric conversion device 131a is configured to convert the third optical signal, the fourth optical signal, and the fifth optical signal into a first electrical signal. The first electrical power splitter 132 is connected to the first photoelectric conversion device 131a and is configured to split the first electrical signal into two sub-signals. The two sub-signals carry the same information.

[0145] The processing component 20 includes a first MAC module 21 and a second MAC module 22. The first MAC module 21 is connected to the first receiving component 11 and the third receiving component 13, and is used to perform uplink scheduling on the first type ONU, first subtype ONU, and second subtype ONU corresponding to the first receiving component 11 and the third receiving component 13, and to recover uplink data sent by the first type ONU, first subtype ONU, and second subtype ONU from the electrical signals output by the first receiving component 11 and / or the electrical signals output by the third receiving component 13. The second MAC module 22 is connected to the second receiving component 12, and is used to perform uplink scheduling on the second type ONU corresponding to the second receiving component 12, and to recover uplink data sent by the second type ONU from the electrical signals output by the second receiving component 12.

[0146] In the embodiment of the present application, since the MAC protocols supported by the first and third type ONUs belong to the same standard system, they can be managed uniformly by the first MAC module 21. That is, the MAC protocols supported by the first MAC module 21 belong to the same standard system as the MAC protocols supported by the first and third type ONUs. The MAC protocols supported by the second MAC module 22 belong to the same standard system as the MAC protocols supported by the second type ONU.

[0147] The first MAC module 21 includes a first single-rate BCDR circuit 21a and a second single-rate BCDR circuit 21b. The first single-rate BCDR circuit 21a and the second single-rate BCDR circuit 21b each support different rates. The first single-rate BCDR circuit 21a and the second single-rate BCDR circuit 21b are each connected to the first electrical power splitter 132 and are each configured to receive one of the two sub-signals output by the first electrical power splitter 132 at a corresponding rate. Here, the first single-rate BCDR circuit 21a supports a rate of 10 Gbps, and the second single-rate BCDR circuit 21b supports a rate of 1.25 Gbps. In other words, the first MAC module 21 can support either 1.25 Gbps or 10 Gbps.

[0148] Optionally, the first MAC module 21 further includes a third single-rate BCDR circuit 21d, which is connected to the first receiving component 11. It is used to receive the electrical signal output by the first receiving component 11 at a corresponding rate. Here, the third single-rate BCDR circuit 21d supports a rate of 1.25 Gbps. In other embodiments, the electrical signal output by the first receiving component 11 can also be received by the second single-rate BCDR circuit 21b. In this case, a switch is required to select whether to receive the electrical signal output by the first receiving component 11 or the electrical signal output by the third receiving component 13. The switch has two input terminals, an output terminal, and a control terminal. The two input terminals are respectively connected to the first receiving component 11 and an output terminal of the first electrical power splitter 132. The output terminal is connected to the second single-rate BCDR circuit 21b, and the control terminal is connected to the first MAC module 21.

[0149] The rate supported by the second MAC module 22 corresponds to the uplink rate of the second type ONU, which can be 12.5Gbps, 25Gbps or 50Gbps. It should be noted that the second MAC module 22 also has a BCDR circuit of the corresponding rate, which is not shown in the figure.

[0150] In the embodiment shown in FIG3 , two single-speed BCDR circuits are used to correspond to the uplink transmission rate of the first type of ONU and the uplink transmission rate of the third type of ONU, respectively, which is beneficial to reducing the cost of the optical communication device.

[0151] The first MAC module 21 selectively receives data of different rates recovered by the first single-rate BCDR circuit and the second single-rate BCDR circuit based on scheduling information from the first and second time slot scheduling mechanisms. As previously described, the first time slot scheduling mechanism enables the first subclass ONU to transmit the third optical signal in the second time slot group, the second subclass ONU to transmit the fourth optical signal in the second time slot group, the fourth subclass ONU to transmit the fifth optical signal in the first time slot group, and the fifth subclass ONU to transmit the sixth optical signal in the first time slot group. The second time slot scheduling mechanism enables the symmetrical second subclass ONUs, the asymmetrical second subclass ONUs, and the first subclass ONUs to transmit optical signals in a time-division multiplexed manner within the second time slot group. Therefore, based on the scheduling information from the first and second time slot scheduling mechanisms, the first MAC module can determine the time slots of the symmetrical ONUs, the asymmetrical ONUs, and the first subclass ONUs within the third class ONUs. In the time slots of the symmetrical ONUs (i.e., the symmetrical second subclass ONUs) in the third category ONUs, the first MAC module 21 receives the data recovered by the first single-speed BCDR circuit 21a; in the time slots of the asymmetrical ONUs (including the first subclass ONUs and the asymmetric second subclass ONUs) in the third category ONUs and the time slots of the first category ONUs, the first MAC module 21 receives the data recovered by the second single-speed BCDR circuit 21b.

[0152] The second MAC module 22 is connected to the first MAC module 21. The first MAC module 21 and the second MAC module 22 synchronize bandwidth allocation information to implement the aforementioned first time slot scheduling mechanism. The bandwidth allocation information is used to indicate at least the time slots included in the first time slot group and the time slots included in the second time slot group.

[0153] Optionally, the third receiving component 13 further includes a first LA 13a and a second LA 13b, wherein the first LA 13a is connected between one output end of the first electric power divider 132 and the first single-speed BCDR circuit 21a, and the second LA 13b is connected between the other output end of the first electric power divider 132 and the second single-speed BCDR circuit 21b.

[0154] In the embodiment of the present application, the photoelectric conversion device and the electrical device in each receiving component can be packaged in a coaxial tube shell. This structure is called a transistor outline can (TO-CAN), which can also be called a receiver (Rx).

[0155] With the advancement of optical communication technology, PON systems are moving towards higher transmission rates. However, the aforementioned fifth-subtype ONUs, due to their large upstream wavelength coverage, limit their use in PON systems. Therefore, the fifth-subtype ONUs need to be decommissioned first. After the fifth-subtype ONUs are decommissioned, time slots can be reallocated. After the fifth-subtype ONUs are decommissioned, the PON system includes the fourth-subtype ONUs but not the fifth-subtype ONUs. The following describes the operation of the optical communication device after the fifth-subtype ONUs are decommissioned.

[0156] Optionally, the second receiving component 12 is further configured to receive the second optical signal sent by the second-class ONU in the first time slot group and the second time slot group. That is, after the fifth-class ONU is disconnected from the network, the first time slot group and the second time slot group may no longer be distinguished for the second-class ONU. The third receiving component 13 is further configured to receive the fifth optical signal sent by the fourth-class ONU in the first time slot group, and to receive the third optical signal sent by the first-class ONU and the fourth optical signal sent by the second-class ONU in the second time slot group. The processing component 20 is further configured to enable the third receiving component to receive the third optical signal sent by the first-class ONU and the fourth optical signal sent by the second-class ONU in a time division multiplexing manner in the second time slot group through a second time slot scheduling mechanism. That is, after the fifth-class ONU is disconnected from the network, the time slots in the first time slot group are used to schedule the fourth-class ONU, and the time slots in the second time slot group are used to schedule the first-class ONU and the second-class ONU.

[0157] Assume that the first stage is before the fifth sub-category ONU is disconnected from the network, and the second stage is after the fifth sub-category ONU is disconnected from the network. The following describes the time slot usage in the first and second stages and the working process of the optical communication device with reference to FIG4.

[0158] Figure 4 is a schematic diagram of time slot allocation before and after network disconnection, provided by an embodiment of the present application. In Figure 4 , the first time slot group and the second time slot group each include two time slots. The number of time slots included in the first time slot group and the second time slot group is for example only and is not intended to be limiting. The allocation of time slots in the first time slot group and the second time slot group can be adjusted based on the number of ONUs in the PON system, the ONU type, and the service information used by the ONUs.

[0159] Part (a) of Figure 4 illustrates the time slot allocation method in the first phase. As shown in Part (a) of Figure 4, the time slots in the first time slot group are allocated to the first type of ONU (EPON ONU), and the time slots in the second time slot group are allocated to the second type of ONU (50G PON) and the first sub-type ONU and the second sub-type ONU in the third type of ONU (10G EPON) in a wavelength division multiplexing manner.

[0160] In the first stage: the first receiving component 11 receives the first optical signal sent by the first type ONU in the first time slot group, and receives the second optical signal sent by the second type ONU, the third optical signal sent by the first subtype ONU, and the fourth optical signal sent by the second subtype ONU in the second time slot group; the second receiving component receives the second optical signal sent by the second type ONU in the second time slot group; the third receiving component receives the third optical signal sent by the first subtype ONU and the fourth optical signal sent by the second subtype ONU in the second time slot group.

[0161] In the first time slot group, the processing component 20 receives the electrical signal output by the first receiving component 11 through the first MAC module 21, and obtains the uplink data sent by the first type ONU from the electrical signal output by the first receiving component 11. In the second time slot group, the processing component 20 receives the electrical signal output by the third receiving component 13 through the first MAC module 21, and obtains the uplink data sent by the first subtype ONU and the second subtype ONU from the electrical signal output by the third receiving component 13; in the second time slot group, the processing component 20 receives the electrical signal output by the second receiving component 12 through the second MAC module 22, and obtains the uplink data sent by the second type ONU from the electrical signal output by the second receiving component 12.

[0162] Part (b) of Figure 4 illustrates the time slot allocation method during the second phase. As shown in part (b) of Figure 4, the fourth subclass ONU in the first class ONU (EPON ONU) and the first and second subclass ONUs in the third class ONU (10G EPON ONU) correspond to the first row of time slots, while the second class ONU (50G PON) corresponds to the second row of time slots. The two rows of time slots are aligned in time. As can be seen, during the second phase, the second and third receiving components receive the optical signals transmitted by the corresponding ONUs using wavelength division multiplexing, and the third receiving component receives the optical signals transmitted by the fourth subclass ONU, the first subclass ONU, and the second subclass ONU using time division multiplexing.

[0163] In the second stage: the first receiving component 11 receives the second optical signal sent by the second type ONU and the fifth optical signal sent by the fourth subtype ONU in the first time slot group, and receives the second optical signal sent by the second type ONU, the third optical signal sent by the first subtype ONU, and the fourth optical signal sent by the second subtype ONU in the second time slot group; the second receiving component 12 receives the second optical signal sent by the second type ONU in the first time slot group and the second time slot group; the third receiving component 13 receives the fifth optical signal sent by the fourth subtype ONU in the first time slot group, and receives the third optical signal sent by the first subtype ONU and the fourth optical signal sent by the second subtype ONU in the second time slot group.

[0164] The processing component 20 no longer receives or ignores the electrical signal output by the first receiving component 11. In both the first and second time slot groups, the processing component 20 receives the electrical signal output by the second receiving component 12 through the second MAC module 22, and obtains the uplink data sent by the second type ONU from the electrical signal output by the second receiving component 12. The processing component 20 also receives the electrical signal output by the third receiving component 13 through the first MAC module 21 in the first time slot group, and obtains the uplink data sent by the fourth subclass ONU from the electrical signal output by the third receiving component 13. In the second time slot group, the processing component 20 also receives the electrical signal output by the third receiving component 13 through the first MAC module 21, and obtains the uplink data sent by the first subclass ONU and the second subclass ONU from the electrical signal output by the third receiving component 13.

[0165] In the embodiment of the present application, the receiving wavelength range of the first receiving component 11 is 1260 nm-X nm, where X is less than or equal to 1360 and greater than 1330. Here, the receiving wavelength range of the first receiving component is the filtering range of the filter device corresponding to the first receiving component. The filter device corresponding to the first receiving component is used to filter out optical signals of the corresponding wavelength range from the uplink optical signal received by the optical communication device, and send the filtered optical signals to the first receiving component.

[0166] In actual network deployment, the optical communication device is typically part of the optical transmission line (OLT), which is connected to multiple optical network units (ONUs) via an optical network (ODN). If there is reflection on the ODN and the receiving wavelength range of the first receiving component overlaps with the downstream wavelength of the second-category ONU, the downstream optical signal of the second-category ONU may be reflected back to the OLT by the ODN and enter the first receiving component. This can affect the reception and data recovery of upstream signals by the first and third-category ONUs. To mitigate this risk, the receiving wavelength range of the first receiving component can be set to not overlap with the downstream wavelength of the second-category ONU. For example, when the downstream wavelength of the second-category ONU is 1340nm-1344nm, X can be set to less than or equal to 1340. To avoid affecting the normal reception of upstream signals by the first-category ONU, X needs to be greater than 1330.

[0167] For example, X is equal to 1335 or 1340, etc.

[0168] The second receiving component 12 is used to receive the second optical signal sent by the second-type ONU. Therefore, the receiving wavelength range of the second receiving component 12 can be consistent with the upstream wavelength of the second-type ONU, which is 1284nm-1288nm. The third receiving component 13 is used to receive the third optical signal sent by the first-subtype ONU and the fourth optical signal sent by the second-subtype ONU. Therefore, the receiving wavelength range of the third receiving component 13 is a combination of the upstream wavelength of the first-subtype ONU and the upstream wavelength of the second-subtype ONU, that is, including 1260nm-1280nm and 1290nm-1330nm.

[0169] Optionally, the optical communication device further includes an optical path control component, which is used to send the optical signals received by the optical communication device to the corresponding receiving components. Exemplarily, the optical path control component includes a splitter 41, filters 42, and 43. The splitter 41 is used to split the optical signals received by the optical communication device into two paths, one of which is sent to the first receiving component 11, and the other is filtered by the filter 42 and then sent to the second receiving component 12; the other is filtered by the filter 43 and then sent to the third receiving component 13. The filtering range of the filter 42 is the receiving wavelength range of the second receiving component 12. The filtering range of the filter 43 is the receiving wavelength range of the third receiving component 13.

[0170] Optionally, the optical communication device further includes a transmitting component 30. The transmitting component 30 is used to transmit optical signals to the first type ONU, the second type ONU, and the third type ONU. For example, in the embodiment shown in FIG3 , the transmitting component 30 includes a first transmitting unit 31 (also called a first transmitter (Tx)) and a second transmitting unit 32. The first transmitting unit 31 is used to transmit optical signals with a wavelength of 1480nm-1500nm (corresponding to the downstream wavelength of the first type ONT). The second transmitting unit 32 is used to transmit optical signals with a wavelength of 1575nm-1580nm (corresponding to the downstream wavelength of the third type ONU) and an optical signal with a wavelength of 1340nm-1344nm (corresponding to the downstream wavelength of the second type ONU). The first transmitting unit 31 is encapsulated in a coaxial tube shell, and the second transmitting unit 32 is encapsulated in a coaxial tube shell. The downstream channel between the OLT and the ONU can be a wavelength division multiplexing downstream wavelength channel.

[0171] Optionally, the transmitting component 30 further includes a combiner 33 , which is configured to combine the optical signals output by the first transmitting unit 31 and the second transmitting unit 32 into one channel and then output the combined optical signals from the optical communication device.

[0172] In other embodiments, the first transmitting unit 21 and the second transmitting unit 22 can also be packaged in the same coaxial tube shell, or the second transmitting unit 22 can be replaced by two independently packaged transmitting units, one for sending 1575nm-1580nm optical signals and the other for sending 1340nm-1344nm optical signals.

[0173] It should be noted that the aforementioned description uses the example of the third-category ONU including the first subcategory ONU and the second subcategory ONU. In other embodiments, the third-category ONU may include only the first subcategory ONU or the second subcategory ONU. In this case, the third receiving component is configured to receive the third optical signal transmitted by the first subcategory ONU or the fourth optical signal transmitted by the second subcategory ONU in the second time slot group. The third receiving component receives the third optical signal or the fourth optical signal in the second time slot group simultaneously with the second receiving component's reception of the second optical signal via wavelength division multiplexing.

[0174] FIG5 is a schematic diagram of the structure of another optical communication device provided by an embodiment of the present application. The optical communication device shown in FIG5 differs from the optical communication device shown in FIG3 in that the structures of the third receiving component 13 and the first MAC module 21 are different.

[0175] As shown in Figure 5, the third receiving component 13 includes a second photoelectric conversion device 131b. The second photoelectric conversion device 131b is used to convert the third optical signal, the fourth optical signal and the fifth optical signal into a second electrical signal.

[0176] The first MAC module 21 includes a dual-rate BCDR circuit 21c, which is connected to the second optical-to-electrical conversion device 131b and is configured to selectively receive the second electrical signal at the first rate and / or the second rate. The first MAC module 21 selectively receives data at different rates recovered by the dual-rate BCDR circuit 21c based on scheduling information from the first and second time slot scheduling mechanisms.

[0177] The first time slot scheduling mechanism and the second time slot scheduling mechanism used by the optical communication device in Figure 5 are the same as those in the embodiment shown in Figure 3. Therefore, the time slot allocation method corresponding to Figure 5 is also shown in Figure 4, and the working process of the optical communication device is also the same as that in Figure 4, which will not be repeated here.

[0178] Figure 6 is a schematic diagram of the structure of another optical communication device provided by an embodiment of the present application. The difference between the optical communication device shown in Figure 6 and the optical communication device shown in Figure 3 lies in the different structures of the third receiving component and the first MAC module.

[0179] As shown in FIG6 , the third receiving assembly 13 includes a third photoelectric conversion device 131 c and a fourth photoelectric conversion device 131 d. The third photoelectric conversion device 131 c is configured to convert the fourth optical signal into a third electrical signal. The fourth photoelectric conversion device 131 d is configured to convert the third optical signal and the fifth optical signal into a fourth electrical signal. The third photoelectric conversion device 131 c and the fourth photoelectric conversion device 131 d are each encapsulated in a coaxial tube housing.

[0180] The first MAC module 21 includes a first single-rate BCDR circuit 21a and a dual-rate BCDR circuit 21c. The first single-rate BCDR circuit 21a is connected to the fourth photoelectric converter 131d and is configured to receive the fourth electrical signal at the first rate. The dual-rate BCDR circuit 21c is connected to the third photoelectric converter 131c and is configured to selectively receive the third electrical signal at the first rate or the second rate. The details regarding the first and second rates are described in the embodiment shown in FIG3 and are not further described here.

[0181] The first MAC module 21 receives data of different rates recovered by the first single-rate BCDR circuit 21 a and the dual-rate BCDR circuit 21 c according to scheduling information of the first time slot scheduling mechanism and the second time slot scheduling mechanism.

[0182] In the embodiment shown in Figure 6, the optical path control assembly includes an optical splitter 41, filters 42, 43, and 44. Optical splitter 41 is used to split the optical signal received by the optical communication device into two paths: one path is sent to the first receiving assembly 11, and the other path is filtered by filter 42 and then sent to the second receiving assembly 12. After filtering by filter 43, the other path is sent to the third photoelectric converter of the third receiving assembly 13; after filtering by filter 44, the other path is sent to the fourth photoelectric converter of the third receiving assembly 13. The filtering range of filter 42 is the receiving wavelength range of the second receiving assembly 12. The combined filtering range of filters 43 and 44 is the receiving wavelength range of the third receiving assembly 13.

[0183] Figure 7 is a schematic diagram of the structure of another optical communication device provided in an embodiment of the present application. The optical communication device shown in Figure 7 differs from the optical communication device shown in Figure 6 in the structure of the third receiving component 13. In Figure 7, the third photoelectric conversion device 131c and the fourth photoelectric conversion device 131d are packaged in the same coaxial tube housing. This structure can be referred to as a double-retracted TO. The double-retracted TO has two output terminals: one output terminal is used to output the third electrical signal output by the third photoelectric conversion device 131c, and the other output terminal is used to output the fourth electrical signal output by the fourth photoelectric conversion device 131d.

[0184] The first MAC module 21 includes a first single-rate BCDR circuit 21a and a dual-rate BCDR circuit 21c. The first single-rate BCDR circuit 21a is connected to the corresponding output terminal of the fourth photoelectric converter 131d and is configured to receive the third electrical signal at the first rate. The dual-rate BCDR circuit 21c is connected to the corresponding output terminal of the third photoelectric converter 131c and is configured to selectively receive the fourth electrical signal at the first rate or the second rate. The first MAC module 21 receives data at different rates recovered by the first single-rate BCDR circuit 21a and the dual-rate BCDR circuit 21c based on scheduling information from the first and second time slot scheduling mechanisms.

[0185] As mentioned above, since the second subclass ONU is divided into symmetric second subclass ONU and asymmetric second subclass ONU, the uplink transmission rate of the symmetric second subclass ONU is 10 Gbps, and the uplink transmission rate of the asymmetric second subclass ONU is 1.25 Gbps. Therefore, in the embodiments shown in Figures 6 and 7, the dual-speed BCDR circuit 21c is used to receive the fourth electrical signal at the second rate in the time slot of the symmetric second subclass ONU, and to receive the fourth electrical signal at the first rate in the time slot of the asymmetric second subclass ONU.

[0186] Assume that the first stage is before the fifth sub-category ONU is disconnected from the network, and the second stage is after the fifth sub-category ONU is disconnected from the network. The following describes the time slot usage in the first and second stages and the working process of the optical communication device with reference to FIG8.

[0187] Figure 8 is a schematic diagram of time slot allocation before and after network delisting, provided in an embodiment of the present application. As shown in Figure 8 , both the first time slot group and the second time slot group include two time slots. Part (a) of Figure 8 illustrates the time slot allocation method during the first phase. Part (b) of Figure 8 illustrates the time slot allocation method during the second phase.

[0188] As shown in part (a) of Figure 8, the time slots in the first time slot group are used to be allocated to the first type of ONU (EPON ONU), and the time slots in the second time slot group are used to be allocated to the first sub-type ONU and the second sub-type ONU in the second type of ONU (50G PON) and the third type of ONU (10G EPON) in a wavelength division multiplexing manner.

[0189] In the first stage: the first receiving component 11 receives the first optical signal sent by the first type ONU in the first time slot group, and receives the second optical signal sent by the second type ONU, the third optical signal sent by the first subtype ONU, and the fourth optical signal sent by the second subtype ONU in the second time slot group; the second receiving component 12 receives the second optical signal sent by the second type ONU in the second time slot group; the third photoelectric conversion device in the third receiving component 13 receives the fourth optical signal sent by the second subtype ONU in the second time slot group, and the fourth photoelectric conversion device receives the third optical signal sent by the first subtype ONU and the fifth optical signal sent by the fourth subtype ONU in the second time slot group.

[0190] The processing component 20 receives the electrical signal output by the first receiving component 11 through the first MAC module 21 in the first time slot group and obtains the uplink data sent by the first type ONU from the electrical signal output by the first receiving component 11. The processing component 20 receives the electrical signal output by the first receiving component 11 through the first MAC module 21 in the second time slot group and obtains the uplink data sent by the asymmetric ONUs in the first sub-type and second sub-type ONUs from the electrical signal output by the first receiving component 11. The processing component 20 receives the electrical signal output by the second receiving component 12 through the second MAC module 22 in the second time slot group and obtains the uplink data sent by the second type ONU from the electrical signal output by the second receiving component 12. The processing component 20 receives the electrical signal output by the fourth photoelectric conversion device of the third receiving component 13 through the first MAC module 21 in the second time slot group and obtains the uplink data sent by the symmetric ONUs in the second sub-type ONU from the electrical signal output by the fourth photoelectric conversion device. The processing component 20 does not receive or ignores the electrical signal output by the third photoelectric conversion device.

[0191] As shown in part (b) of Figure 8, the fourth subclass ONU in the first class ONU (EPON ONU), the first subclass ONU in the third class ONU (10G EPON ONU), and the asymmetric ONU in the second subclass ONU correspond to the first row of time slots, the symmetric ONU in the second subclass ONU corresponds to the second row of time slots, and the second class ONU (50G PON) corresponds to the third row of time slots. The three rows of time slots are aligned in the time dimension. It can be seen that in the second phase, the second and third receiving components receive the optical signals transmitted by the corresponding ONUs in a wavelength division multiplexing manner, and the third receiving component receives the optical signals transmitted by the fourth subclass ONU, the first subclass ONU, and the second subclass ONU in a time division multiplexing manner.

[0192] In the second phase: the first receiving component 11 receives the second optical signal sent by the second-class ONU, the third optical signal sent by the first subclass ONU, the fourth optical signal sent by the second subclass ONU, and the fifth optical signal sent by the fourth subclass ONU in the first time slot group and the second time slot group; the second receiving component 12 receives the second optical signal sent by the second-class ONU in the first time slot group and the second time slot group; the third receiving component 13 receives the third optical signal sent by the first subclass ONU, the fourth optical signal sent by the second subclass ONU, and the fifth optical signal sent by the fourth subclass ONU in the first time slot group and the second time slot group. The third optical signal sent by the first subclass ONU, the fourth optical signal sent by the second subclass ONU, and the fifth optical signal sent by the fourth subclass ONU are received in time division multiplexing.

[0193] In some examples, in the second stage, the first time slot group and the second time slot group may no longer be divided, that is, the second type of ONU is scheduled in the entire time dimension; at the same time, the first subclass ONU, the second subclass ONU and the fourth subclass ONU are scheduled in the entire time dimension.

[0194] In other examples, in this second stage, the first time slot group and the second time slot group are still divided, the first time slot group is used to schedule the first subclass ONU and the fourth subclass ONU, and the second time slot group is used to schedule the second subclass ONU; or, the second time slot group is used to schedule the first subclass ONU and the fourth subclass ONU, and the first time slot group is used to schedule the second subclass ONU; or, the first time slot group is used to schedule the first subclass ONU, the fourth subclass ONU and the asymmetric second subclass ONU, and the second time slot group is used to schedule the symmetric second subclass ONU; or, the second time slot group is used to schedule the first subclass ONU, the fourth subclass ONU and the asymmetric second subclass ONU, and the first time slot group is used to schedule the symmetric second subclass ONU.

[0195] The processing component 20 does not receive or ignores the electrical signal output by the first receiving component 11. The processing component 20 receives the second electrical signal output by the second receiving component 12 in the first time slot group and the second time slot group through the second MAC module 22, and obtains the uplink data sent by the second type ONU from the second electrical signal output by the second receiving component 12. The processing component 20 receives the electrical signal output by the fourth photoelectric conversion device in the first time slot group and the second time slot group through the first MAC module 21, and obtains the uplink data sent by the second subtype ONU from the electrical signal output by the fourth photoelectric conversion device. The processing component 20 also receives the electrical signal output by the third photoelectric conversion device through the first MAC module 21, and obtains the uplink data sent by the first subtype ONU and the uplink data sent by the fourth subtype ONU from the electrical signal output by the third photoelectric conversion device.

[0196] The aforementioned embodiments are all described using the example of a third-category ONU that does not include the third subclass. However, if the third-category ONU also includes the third subclass ONU, the first receiving component 11 is further configured to receive the seventh optical signal transmitted by the third subclass ONU in the first time slot group. Accordingly, the scheduling information generated by the second time slot scheduling mechanism is further configured to indicate the authorized bandwidth of the third subclass ONU and the authorized bandwidth of the first-category ONU, and the authorized bandwidths of the third subclass ONU and the first-category ONU do not overlap in time. In this way, the first receiving component 11 receives the seventh optical signal transmitted by the third subclass ONU and the first optical signal transmitted by the first-category ONU in the first time slot group using time division multiplexing.

[0197] Since the uplink wavelengths of the third subclass ONU and the fifth subclass ONU are the same, during the PON system upgrade process, the third subclass ONU and the fifth subclass ONU need to be de-networked together. After the third subclass ONU and the fifth subclass ONU are de-networked, the working process of the optical communication device is the same as the aforementioned second stage.

[0198] In the embodiments shown in Figures 3 to 8, the optical communication device uses a combination of time division multiplexing and wavelength division multiplexing to enable the coexistence of first, second, and third type ONUs in the PON system. In other embodiments, the optical communication device can also use time division multiplexing to enable the coexistence of first, second, and third type ONUs. The following example illustrates the coexistence of first, second, and third type ONUs using time division multiplexing.

[0199] Figure 9 is a schematic diagram of the structure of another optical communication device provided in an embodiment of the present application. The optical communication device is applicable to a PON system including the aforementioned first type ONU, second type ONU, and third type ONU.

[0200] As shown in Figure 9, the optical communication device includes a first receiving component 11, a second receiving component 12, and a processing component 20. The first receiving component 11 is configured to receive a first optical signal transmitted by a first type of ONU and a third optical signal transmitted by a third type of ONU in a first time slot group. The second receiving component 12 is configured to receive a second optical signal transmitted by a second type of ONU in a second time slot group. The first time slot group includes at least one time slot, and the second time slot group includes at least one time slot.

[0201] The processing component 20 is used to make the first time slot group and the second time slot group non-overlap in the time dimension through the first time slot scheduling mechanism, and the processing component 20 is also used to make the first receiving component 11 receive the first optical signal and the third optical signal in the first time slot group in a time division multiplexing manner through the third time slot scheduling mechanism.

[0202] Here, since both the first and third type ONUs are scheduled in the time slots of the first time slot group, a third time slot scheduling mechanism is required to ensure that the upstream data of the first and third type ONUs do not conflict. The third time slot scheduling mechanism is used to generate bandwidth allocation information (also called scheduling information), which is used to indicate the authorized bandwidth of the first type ONU and the authorized bandwidth of the third type ONU, and the authorized bandwidth of the first type ONU and the authorized bandwidth of the third type ONU do not overlap in the time dimension.

[0203] In the embodiment shown in Figure 9, the first receiving component 11 is used to receive the first optical signal transmitted by the first type ONU and the third optical signal transmitted by the third type ONU. The maximum upstream wavelength range of the first and third type ONUs is 1260 nm to 1360 nm. Therefore, the receiving wavelength range of the first receiving component 11 is relatively large. For example, the receiving wavelength range of the first receiving component 11 can be 1260 nm to 1360 nm, or the upper limit of the receiving wavelength range of the first receiving component 11 can be slightly less than 1360 nm, such as 1340 nm. The second receiving component 12 is used to receive the second optical signal transmitted by the second type ONU. Therefore, the receiving wavelength range of the second receiving component 12 can be consistent with the upstream wavelength of the second type ONU, which is 1284 nm to 1288 nm.

[0204] Optionally, the first receiving component 11 includes a fifth photoelectric conversion device 111a and a second electrical power splitter 112. The fifth photoelectric conversion device 111 is configured to convert the first optical signal and the third optical signal into a first electrical signal. The second electrical power splitter 112 is connected to the fifth photoelectric conversion device 111a and is configured to split the first electrical signal into two sub-signals. These two sub-signals carry the same information.

[0205] Optionally, the second receiving component 12 includes at least a photoelectric conversion device 121 for converting the second optical signal into an electrical signal.

[0206] The fifth photoelectric conversion device 111 a and the photoelectric conversion device 121 may also be referred to as receivers (Rx), and may be respectively packaged in corresponding coaxial tube packages. This structure is called a transistor outline can (TO-CAN).

[0207] The processing component 20 includes a first MAC module 21 and a second MAC module 22. The first MAC module 21 is connected to the first receiving component 11 and is used to perform uplink scheduling for the first and third type ONUs corresponding to the first receiving component 11 and to recover uplink data sent by the first and third type ONUs from the optical signals received by the first receiving component 11. The second MAC module 22 is connected to the second receiving component 12 and is used to perform uplink scheduling for the second type ONU corresponding to the second receiving component 12 and to recover uplink data sent by the second type ONU from the optical signals received by the second receiving component 12.

[0208] In the embodiment of the present application, the MAC protocol supported by the first MAC module 21 and the first and third type ONUs belongs to the same standard system, and the MAC protocol supported by the second MAC module 22 and the second type ONU belongs to the same standard system.

[0209] The first MAC module 21 is connected to the second MAC module 22. The first MAC module 21 and the second MAC module 22 synchronize bandwidth allocation information to implement the aforementioned first time slot scheduling mechanism. Here, the bandwidth allocation information is used to indicate at least the time slots included in the first time slot group and the time slots included in the second time slot group.

[0210] The first MAC module 21 includes a first single-rate BCDR circuit 21a and a second single-rate BCDR circuit 21b, each supporting different rates. The first single-rate BCDR circuit 21a and the second single-rate BCDR circuit 21b are respectively connected to the two output terminals of the second electrical power splitter 112 and are respectively configured to receive one of the two sub-signals output by the second electrical power splitter 112 at a corresponding rate. The first MAC module 21 is configured to selectively receive data of different rates recovered by the first single-rate BCDR circuit 21a and the second single-rate BCDR circuit 21b based on scheduling information from a third time slot scheduling mechanism.

[0211] The first single-rate BCDR circuit 21a supports the same rate as the first-category ONU, and the second single-rate BCDR circuit 21b supports the same rate as the third-category ONU. For example, when the first-category ONU is an EPON ONU, the first single-rate BCDR circuit and the first-category ONU both support a rate of 1.25 Gbps. When the third-category ONU is a 50G PON ONU, the second single-rate BCDR circuit and the third-category ONU both support a rate of 10.3125 Gbps.

[0212] The rate supported by the second MAC module 22 corresponds to the uplink rate of the second type ONU, which can be 12.5Gbps, 25Gbps or 50Gbps. It should be noted that the second MAC module 22 also has a single-speed BCDR circuit of the corresponding rate, which is not shown in the figure.

[0213] In the embodiment shown in FIG9 , two single-speed BCDR circuits are used to correspond to the uplink transmission rate of the first type of ONU and the uplink transmission rate of the third type of ONU, respectively, which is beneficial to reducing the cost of the optical communication device.

[0214] Optionally, the first receiving component 11 further includes a first limiting amplifier (LA) 113a and a second LA 113b. The first LA 113a is connected between one output terminal of the first power splitter 112 and the first single-rate BCDR circuit 21a, and the second LA 113b is connected between the other output terminal of the first power splitter 112 and the second single-rate BCDR circuit 21b. The first receiving component uses the LA to amplify the electrical signal before outputting it to the corresponding single-rate BCDR circuit, which facilitates the single-rate BCDR circuit in recovering data from the received electrical signal.

[0215] Optionally, the optical communication device may also include a sending component 30. For details about the sending component 30, please refer to the embodiment shown in FIG3 and will not be described in detail here.

[0216] Figure 10 is a schematic diagram of the structure of another optical communication device provided in an embodiment of the present application. The difference from the optical communication device shown in Figure 9 is that the structures of the first receiving component 11 and the first MAC module 21 are different. As shown in Figure 10, the first receiving component 11 includes a sixth photoelectric conversion device 111b, which is used to convert the first optical signal and the third optical signal into a fifth electrical signal. The first MAC module 21 includes a dual-speed BCDR circuit 21c, which is connected to the sixth photoelectric conversion device 111b and is used to selectively receive the fifth electrical signal at the first rate and / or the second rate. The first MAC module 21 is used to selectively receive data of different rates output by the dual-speed BCDR circuit 21c according to the scheduling information of the third time slot scheduling mechanism.

[0217] Since the first MAC module 21 can selectively recover data from the first electrical signal at different rates through the dual-speed BCDR 21c, the first electrical power splitter in the first receiving component 11 can be omitted based on the structure shown in Figure 9, thereby simplifying the structure of the first receiving component 11.

[0218] Optionally, the first receiving component 11 further includes an LA 113c connected between the first photoelectric conversion device 111 and the dual-speed BCDR circuit 21c. The first receiving component 11 uses the LA 113c to amplify the electrical signal before outputting it to the dual-speed BCDR circuit, which facilitates the dual-speed BCDR circuit in recovering data from the received electrical signal.

[0219] In the embodiment shown in FIG10 , the first MAC module 21 is further configured to output a rate selection signal according to the bandwidth allocation information. The rate selection signal is used to control the filtering bandwidth of the filter device corresponding to the first receiving component 11 .

[0220] Optionally, the first MAC module 21 is further configured to output a control signal according to the bandwidth allocation information, where the control signal is used to control the working bandwidth of the LA 13c, so that the working bandwidth of the LA 13c is dynamically adjusted with the bandwidth of the optical signal to reduce noise and achieve better receiving sensitivity.

[0221] Figure 11 is a schematic diagram of the relationship between a first time slot group and a second time slot group provided by an embodiment of the present application. As shown in Figure 11, the time slots in the first time slot group are used to schedule the first type of ONU and the third type of ONU in the form of time division multiplexing, and the time slots in the second time slot group are used to schedule the second type of ONU.

[0222] The processing component 20 receives the electrical signal output by the first receiving component 11 through the first MAC module 21, and obtains the uplink data sent by the first type ONU and the third type ONU from the electrical signal output by the first receiving component 11; the processing component 20 receives the electrical signal output by the second receiving component 12 through the second MAC module 22, and obtains the uplink data sent by the second type ONU from the electrical signal output by the second receiving component 12.

[0223] Optionally, the first MAC module 21 and the second MAC module 22 may be integrated on the same physical chip, or the first MAC module 21 and the second MAC module 22 may be respectively set on different physical chips.

[0224] In the embodiments of the present application, the physical chip may be a field-programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on chip (SoC), a central processor unit (CPU), a digital signal processor (DSP), a programmable logic device (PLD) or other integrated chips, and the present application does not impose any restrictions on this.

[0225] The following is an introduction to the first time slot scheduling mechanism adopted by the processing component.

[0226] In an embodiment of the present application, the first time slot scheduling mechanism includes determining a first time slot group and a second time slot group in a target period based on bandwidth demand-related information of the multiple ONUs, wherein the target period includes M time slots, where M is greater than 1 and is an integer, the first time slot group includes X time slots of the M time slots, and the second time slot group includes Y time slots of the M time slots, where X and Y are both positive integers, and the sum of X and Y is less than or equal to M. The time slots of the first time slot group are allocated to the first type of ONUs according to the MAC protocol supported by the first type of ONUs, and the time slots of the second time slot group are allocated to the second type of ONUs according to the MAC protocol supported by the second type of ONUs.

[0227] Hereinafter, the time slots in the first time slot group are referred to as first time slots, and the time slots in the second time slot group are referred to as second time slots.

[0228] In one possible embodiment, the first time slot group includes at least two first subsets, any one of the at least two first subsets includes one first time slot or includes at least two consecutive first time slots, and there is at least one second time slot between two adjacent first subsets in the at least two first subsets; and / or, the second time slot group includes at least two second subsets, any one of the at least two second subsets includes one second time slot or includes at least two consecutive time slots, and there is at least one first time slot between two adjacent second subsets in the at least two second subsets.

[0229] By alternating the first subset and the second subset in a target period, the time slots in the target period can be evenly distributed to the ONUs corresponding to the first time slot group and the ONUs corresponding to the second time slot group, thereby minimizing the long waiting time for different types of ONUs to send upstream data.

[0230] In another possible implementation, the first time slot group includes one first time slot or at least two consecutive first time slots; and / or the second time slot group includes one second time slot or at least two consecutive second time slots.

[0231] Optionally, at least one first time slot in the first time slot group is a windowed time slot; and / or at least one second time slot in the second time slot group is a windowed time slot. Setting a windowing period within the first time slot group can prevent the windowing period from affecting normal service communications of the ONU corresponding to the second time slot group. Similarly, setting a windowing period within the second time slot group can prevent the windowing period from affecting normal service communications of the ONU corresponding to the first time slot group.

[0232] In the embodiment of the present application, a windowed timeslot refers to a timeslot in which bandwidth is not authorized but is used to receive registration requests from ONTs to be online, or to perform network operation and maintenance, such as rogue terminal detection and reflection detection.

[0233] Optionally, the first time slot scheduling mechanism further includes: using a time slot outside the target period or at least two consecutive time slots as windowed time slots. In this way, a windowed period can be configured after one or more target periods as needed, making the configuration of the windowed period more flexible.

[0234] Optionally, the information related to the bandwidth requirement of the ONU includes at least one of the number of each type of ONUs and service information of services enabled by the ONU. Optionally, the service information includes service type or latency requirement.

[0235] In this embodiment of the present application, it is assumed that the first time slot group is used to schedule ONUs in the first terminal set, and the second time slot group is used to schedule ONUs in the second terminal set. In this embodiment of the present application, if the number of ONUs in the first terminal set is greater and the bandwidth demand corresponding to the services activated by each ONU is greater, then the proportion of time slots included in the first time slot group in the target period will increase. Similarly, if the number of ONUs in the second terminal set is greater and the bandwidth demand corresponding to the services activated by each ONU is greater, then the proportion of time slots included in the second time slot group in the target period will increase.

[0236] Optionally, the first time slot scheduling mechanism may adopt any one of the following methods to determine the proportion of the time slots included in the first time slot group and the second time slot group in the target cycle.

[0237] First, the bandwidth requirement-related information includes the number of ONUs in the first terminal set and the number of ONUs in the second terminal set. The proportion of the first time slot group in the target period is equal to a first ratio of the number of ONUs in the first terminal set to the sum of the number of ONUs in the first terminal set and the number of ONUs in the second terminal set. Similarly, the proportion of the second time slot group in the target period is equal to a second ratio of the number of ONUs in the second terminal set to the sum of the number of ONUs in the first terminal set and the number of ONUs in the second terminal set.

[0238] The second type of bandwidth demand related information includes the service type activated by each ONU in the first terminal set and the service type activated by each ONU in the second terminal set.

[0239] First, the OLT determines the bandwidth corresponding to the service type of each ONU according to the mapping relationship between the service type and the bandwidth, as the bandwidth requirement of each ONU; then, the ONU counts the sum of the bandwidth requirements of all ONUs in the first terminal set and the sum of the bandwidth requirements of all ONUs in the second terminal set; a third ratio of the sum of the bandwidth requirements of all ONUs in the first terminal set to the sum of the bandwidth requirements of all ONUs in the first terminal set and the second terminal set is determined as the proportion of the first time slot group in the target period; and a fourth ratio of the sum of the bandwidth requirements of all ONUs in the second terminal set to the sum of the bandwidth requirements of all ONUs in the first terminal set and the second terminal set is determined as the proportion of the second time slot group in the target period.

[0240] The third type of bandwidth demand related information includes the number of ONUs in the first terminal set, the number of ONUs in the second terminal set, the service types activated by the ONUs in the first terminal set, and the service types activated by the ONUs in the second terminal set.

[0241] A first ratio of the number of ONUs in the first terminal set to the sum of the number of ONUs in the first terminal set and the second terminal set, and a second ratio of the sum of the bandwidth requirements of all ONUs in the first terminal set to the sum of the bandwidth requirements of all ONUs in the first terminal set and the second terminal set are multiplied by corresponding weights and then added together to obtain a proportion of the first time slot group in the target period; a third ratio of the number of ONUs in the second terminal set to the sum of the number of ONUs in the first terminal set and the second terminal set, and a fourth ratio of the sum of the bandwidth requirements of all ONUs in the second terminal set to the sum of the bandwidth requirements of all ONUs in the first terminal set and the second terminal set are multiplied by corresponding weights and then added together to obtain a proportion of the second time slot group in the target period. The sum of the weight corresponding to the first ratio and the weight corresponding to the second ratio is equal to 1; and the sum of the weight corresponding to the third ratio and the weight corresponding to the fourth ratio is equal to 1.

[0242] The weight corresponding to the first ratio and the weight corresponding to the second ratio, as well as the weight corresponding to the third ratio and the weight corresponding to the fourth ratio can be set as needed, for example, all are 0.5.

[0243] Optionally, in addition to determining the proportion of the first time slot group and the second time slot group, determining the first time slot group and the second time slot group in the target period may also include: determining the distribution method of the first time slot group and the second time slot group based on the delay sensitivity of the ONU in the first terminal set and the delay sensitivity of the ONU in the second terminal set, and the distribution method is used to indicate the number of consecutive first time slot groups and the number of consecutive second time slot groups.

[0244] The higher the delay sensitivity of the ONUs in the first terminal set, the smaller the number of consecutive first time slot groups. The lower the delay sensitivity of the ONUs in the first terminal set, the larger the number of consecutive first time slot groups. The higher the delay sensitivity of the ONUs in the second terminal set, the smaller the number of consecutive second time slot groups. The lower the delay sensitivity of the ONUs in the second terminal set, the larger the number of consecutive second time slot groups.

[0245] For example, the delay sensitivity can be represented by the maximum delay that the ONU can tolerate. The larger the maximum delay that the ONU can tolerate, the higher the delay sensitivity.

[0246] The embodiment of the present application does not limit the specific implementation method of the first time slot scheduling mechanism, which can be set as needed.

[0247] Optionally, the first terminal set includes the first type of ONU, and the second terminal set includes the second type of ONU, such as the embodiments shown in Figure 1, Figure 3, and Figures 5 to 7; or, the first terminal set includes the first type of ONU and the third type of ONU, and the second terminal set includes the second type of ONU, such as the embodiments shown in Figures 9 and 10.

[0248] It should be noted that, in the embodiments shown in Figures 3, 5 to 7, although the second time slot group is used to schedule the first subclass ONU and the second subclass ONU in the second class ONU and the third class ONU, the second class ONU has a higher delay requirement, so only the second class ONU is considered.

[0249] The embodiment of the present application further provides a communication method that can be implemented based on the aforementioned PON system. The communication method is executed by an OLT, for example, by a processing component of the OLT, the processing component including the aforementioned first MAC module and the aforementioned second MAC module.

[0250] The method is used to receive optical signals transmitted by multiple ONUs using multiple receiving components. The multiple receiving components include a first receiving component, a second receiving component, and a third receiving component. For details regarding the first, second, and third receiving components, refer to the aforementioned device embodiment. The multiple ONUs include a first type ONU, a second type ONU, and a third type ONU. For details regarding the first, second, and third types of ONUs, refer to the aforementioned device embodiment.

[0251] In one possible embodiment, the method includes: in a first stage, obtaining the uplink data sent by the first type ONU and the first subclass ONU based on the electrical signal output by the first receiving component in the first time slot group, obtaining the uplink data sent by the second type ONU based on the electrical signal output by the second receiving component in the second time slot group, and obtaining the uplink data sent by the second subclass ONU based on the electrical signal output by the third photoelectric conversion device in the third receiving component in the second time slot group; or, in a second stage, obtaining the uplink data sent by the second type ONU based on the electrical signal output by the second receiving component in the first time slot group and the second time slot group, obtaining the uplink data sent by the second subclass ONU based on the electrical signal output by the third photoelectric conversion device of the third receiving component in the first time slot group and the second time slot group, and obtaining the uplink data sent by the fourth subclass ONU and the uplink data sent by the first subclass ONU based on the electrical signal output by the fourth photoelectric conversion device of the third receiving component.

[0252] This method can be implemented based on the optical communication device shown in FIG. 3 or FIG. 5 . For related content, please refer to the related content of the embodiments shown in FIG. 3 and FIG. 5 .

[0253] In another possible embodiment, the method includes: in a first phase, obtaining, based on the electrical signal output by the first receiving component in a first time slot group, upstream data sent by the first type ONU and the first subtype ONU; in a second time slot group, obtaining, based on the electrical signal output by the second receiving component, upstream data sent by the second type ONU; and in a second time slot group, obtaining, based on the electrical signal output by the third photoelectric conversion device in the third receiving component, upstream data sent by the second subtype ONU; or, in a second phase, obtaining, based on the electrical signal output by the second receiving component, upstream data sent by the second type ONU; and, simultaneously, receiving, based on the third receiving component, upstream data sent by the second subtype ONU, upstream data sent by the fourth subtype ONU, and upstream data sent by the first subtype ONU. The upstream data sent by the second subtype ONU is obtained via the electrical signal output by the third photoelectric conversion device, and the upstream data sent by the fourth subtype ONU and upstream data sent by the first subtype ONU are obtained via the electrical signal output by the fourth photoelectric conversion device.

[0254] This method can be implemented based on the optical communication device shown in FIG. 6 or FIG. 7 . For related content, please refer to the related content of the embodiments shown in FIG. 6 and FIG. 7 .

[0255] In the first phase, the PON system contains all the first, second, and third category ONUs, and the first category ONUs include the fourth and fifth subcategory ONUs. In the second phase, the fifth subcategory ONUs of the first category ONUs and the third subcategory ONUs of the third category ONUs have been decommissioned, or the fifth subcategory ONUs of the first category ONUs and the third subcategory ONUs of the third category ONUs have been upgraded to the second category ONUs, the first subcategory ONUs, or the second subcategory ONUs. That is, the fifth subcategory ONUs and the third subcategory ONUs no longer exist in the PON system.

[0256] By selecting the corresponding receiving component to receive upstream data from the ONU at different stages, the OLT with the same hardware structure can communicate with the existing ONUs in the PON system before and after the PON system upgrade. The OLT hardware structure does not need to be changed before and after the PON system upgrade, which helps reduce costs.

[0257] See FIG12 , which is a flow chart of an optical communication method provided in an embodiment of the present application.

[0258] The communication method provided in the embodiments of the present application can be applied to the aforementioned time-division and wavelength-division multiplexing PON system. The PON system includes an OLT and at least one ONU. After the ONU is connected to the PON network, an activation process can be performed. The communication method provided in the present application can be used as part of the activation process or used independently of the activation process. The communication method provided in the present application includes the following steps:

[0259] S101. The OLT sends a downstream physical frame to an ONU connected to a PON network. The downstream physical frame includes an index of a downstream wavelength channel available in the PON system.

[0260] In a PON system, the OLT can continuously send downstream data to the ONU in a downstream direction (transmit downstream physical frames).

[0261] Specifically, the downlink physical frame includes a downlink physical synchronization block and a payload. The downlink physical synchronization block and the payload can be protected by forward error correction coding (forward error correction coding). The structure of the downlink physical synchronization block may include: a physical synchronization sequence, a counter, and an operation control structure. The physical synchronization sequence contains a fixed delimiter pattern. After receiving the physical synchronization sequence, the ONU uses this sequence to align the downlink physical frame boundaries. The counter is used to count downlink physical frames. The counter value of the current downlink physical frame is incremented by 1 relative to the previous downlink physical frame. The operation control structure includes a main body and an error correction header field. The value in the error correction header field is used by the ONU to perform error correction on the main body.

[0262] The main body of the operation control structure is populated by the OLT and may include a PON ID type (PIT) field and / or a PON ID field. The PIT field is used to identify the ODN architecture, ODN level, and whether the transmission convergence (TC) layer protocol is used. The PON ID field is used to identify the OLT within a range.

[0263] Specifically, the PON identification field may include a management label and a downstream wavelength channel identifier (abbreviated as wavelength channel identifier) ​​provided by the network management system to the OLT. Since PON systems include time division multiplexing (TDM) PONs and time and wavelength division multiplexing (TWDM) PONs, the meaning of the downstream wavelength channel identifiers differs in different types of PON systems.

[0264] In a time division and wavelength division multiplexing (TWDM) PON system, the downstream wavelength channel identifier can identify the index of a downstream wavelength channel currently available in the PON system. The current PON system may include multiple downstream wavelength channels (referred to as a downstream wavelength channel set), and the downstream wavelength channel identifier can identify the index of a portion of the available downstream wavelength channels in the set.

[0265] S102: The ONU determines whether the downstream wavelength channel corresponding to the index of the downstream wavelength channel is available.

[0266] The ONU may receive an index of a downstream wavelength channel sent by the OLT when in a profile learning state. After receiving the first downstream physical frame carrying the index of an available downstream wavelength channel of the PON system, the ONU may determine whether the downstream wavelength channel corresponding to the index of the downstream wavelength channel is available, for example, whether the downstream wavelength can be used for the activation process (whether the downstream wavelength is occupied).

[0267] S103: The ONU determines that the downstream wavelength channel corresponding to the index of the downstream wavelength channel is available, and then enters the sequence number state of the activation process.

[0268] If the downstream wavelength channel can be used for the activation process, the ONU continues the current activation process and enters the sequence number state of the activation process (sending the ONU's sequence number to the OLT). Upon receiving the sequence number sent by the ONU, if the OLT determines that the ONU is a newly connected ONU, it sends the assigned ONU identifier (ID) to the ONU. In addition, the OLT can also send a wavelength adjustment message or a wavelength calibration message to the ONU to facilitate the ONU's tuning of its transmitter to the target upstream wavelength channel for communication with the OLT.

[0269] After completing the subsequent activation process, the ONU may start processing downlink physical frames and sending uplink bursts to the OLT, for example, executing step 506 .

[0270] The ONT activation process involves multiple message exchanges with the OLT. For example, the OLT sends a Sequence Number Request message to the ONT, which then returns a Sequence Number Response message. The OLT also sends a Ranging Request message to the ONT, which then returns a Ranging Response message. Based on the Ranging Response message, the OLT calculates the ONT's equalization parameters and then sends a Ranging Time message to the ONT, which contains the ONT's equalization delay. Once the equalization delay is achieved, the ONT enters the Operational state (completing the activation process). In the Operational state, the ONT can process downlink physical frames and send uplink bursts.

[0271] The uplink message sent by the ONT during the activation process can be carried by the uplink physical frame, and the downlink message sent by the OLT during the activation process can be carried by the payload in the downlink physical frame.

[0272] S104: The ONU determines that the downstream wavelength channel corresponding to the index of the downstream wavelength channel is unavailable, and searches for other available downstream wavelength channels.

[0273] If the downstream wavelength channel is not available for activation, the ONU searches for other available downstream wavelength channels. If other available downstream wavelength channels are found, the ONU enters an asynchronous state in the activation process (eg, discards local burst mode information).

[0274] S105 . The OLT sends a downstream physical frame on the downstream wavelength channel. The downstream physical frame carries user data of the ONU.

[0275] After activation, the ONU can communicate with the OLT using a downstream wavelength channel. For example, the OLT sends a downstream physical frame over the downstream wavelength channel. The downstream physical frame can carry the ONU's user data. The ONU processes the downstream physical frame and obtains the user data.

[0276] In addition, after receiving the equalization delay, the ONU can also calculate the sending window of the uplink data based on the equalization delay and the time slot allocated by the OLT, and send an uplink physical frame to the OLT in the sending window. The uplink physical frame carries the user data of the ONT.

[0277] The communication method provided in this embodiment can be used in a PON system that uses time division multiplexing and wavelength division multiplexing. Since the OLT can notify the ONU of the available downstream wavelength channels in the current PON system through the wavelength channel identifier in the downstream physical frame, communication conflicts caused by wavelength mismatch between the OLT and the ONU are avoided, thereby improving communication efficiency.

[0278] In the communication method provided in this embodiment, the ONU can migrate between different states of the activation process (eg, initial state, mode learning state, sequence number state, and asynchronous state).

[0279] For example, when the ONU determines that the downstream wavelength channel corresponding to the index of the downstream wavelength channel can be used for activation, it can enter the sequence number state (sending the ONU's sequence number to the OLT) from the mode learning state (collecting mode parameters). When the ONU determines that the downstream wavelength channel corresponding to the index of the downstream wavelength channel cannot be used for activation and searches for other downstream wavelength channels that can be used for activation, it can enter the asynchronous state (retaining channel mode information but discarding burst mode information) from the mode learning state.

[0280] Unless otherwise defined, the technical or scientific terms used herein shall have the usual meaning understood by persons of ordinary skill in the field to which this application belongs. The words “first”, “second”, “third” and similar terms used in the patent application specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as “a” or “an” do not indicate a quantitative limitation, but rather indicate the presence of at least one. Words such as “include” or “comprising” and similar words mean that the elements or objects appearing before “include” or “comprising” cover the elements or objects listed after “include” or “comprising” and their equivalents, and do not exclude other elements or objects.

[0281] The above is only an embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the principles of the present application should be included in the scope of protection of the present application.

Claims

1. A communication method, characterized in that: Applied to a passive optical network PON system, the PON system includes an optical line terminal OLT and at least one optical network unit ONU device, the method includes: The ONU receives a first downstream physical frame sent by the OLT, where the first downstream physical frame includes an index of a downstream wavelength channel available to the PON system; The ONU determines whether the downstream wavelength channel corresponding to the index of the downstream wavelength channel is available; If the ONU determines that the downstream wavelength channel corresponding to the index of the downstream wavelength channel is available, it receives a second downstream physical frame sent by the OLT on the downstream wavelength channel.

2. The method according to claim 1, characterized in that The method further comprises: If the ONU determines that the downstream wavelength channel corresponding to the index of the downstream wavelength channel is unavailable, it searches for other available downstream wavelength channels.

3. The method according to claim 1 or 2, characterized in that: The ONU determines whether the downstream wavelength corresponding to the index of the downstream wavelength channel is available, including: The ONU determines whether the index of the downstream wavelength channel included in the operation control body part of the first downstream physical frame can be used for activation.

4. The method according to claim 3, characterized in that The index of the downstream wavelength channel occupies at least 2 bits in the operation control subject field.

5. The method according to claim 2, characterized in that: When the ONU searches for an available downstream wavelength channel, the ONU enters an asynchronous state.

6. The method according to claim 2, characterized in that When the ONU fails to search for an available downstream wavelength channel, the ONU enters an initial state.

7. The method according to claim 1 or 2, characterized in that: If the ONU determines that the downstream wavelength channel corresponding to the index of the downstream wavelength channel is available, the method further includes: The ONU enters the sequence number state of the activation process; After the ONU completes the activation process, the ONU starts to receive a second downstream physical frame sent by the OLT on the downstream wavelength channel, where the second downstream physical frame carries user data of the ONU.

8. The method according to claim 1 or 2, characterized in that: Also includes: The ONU receives the wavelength adjustment message sent by the OLT, and tunes its transmitter to a target upstream wavelength channel according to the wavelength adjustment message.

9. A communication method, characterized in that: Applied to a passive optical network PON system, the PON system includes an optical line terminal OLT and at least one optical network terminal ONU, the method includes: The OLT sends a first downstream physical frame to the ONU, where the first downstream physical frame includes an index of a downstream wavelength channel available to the PON system; The OLT sends a second downstream physical frame to the ONU on the downstream wavelength channel corresponding to the index of the downstream wavelength channel.

10. The method according to claim 9, characterized in that The operation control body field of the first downlink physical frame includes the index of the downlink wavelength channel.

11. The method according to claim 10, characterized in that The index of the downstream wavelength channel occupies 3 bits in the operation control subject field.

12. The method according to any one of claims 9 to 11, characterized in that: Also includes: The OLT sends a wavelength adjustment message or a wavelength calibration message to the ONU.

13. An optical communication device, characterized in that: The optical communication device comprises a processor and a memory, wherein the memory is used to store a software program, and the processor runs or executes the software program stored in the memory so as to make the optical communication device perform the communication method performed by the ONU as claimed in any one of claims 1 to 8, or make the optical communication device perform the communication method performed by the OLT as claimed in any one of claims 9 to 12.

14. An optical communication system, characterized in that: The method comprises an optical line terminal OLT and a plurality of optical network units ONU, wherein the OLT is configured to execute the communication method according to any one of claims 9 to 12 or the ONU is configured to execute the communication method according to any one of claims 1 to 8.

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