Data transmission method of passive optical network (PON), storage medium and electronic device

Abstract

The embodiment of the invention provides a data transmission method of a passive optical network (PON), a storage medium and an electronic device, and the method comprises the steps: detecting the service transmission condition of each subcarrier through an optical line terminal (OLT), and selecting the subcarrier as a windowed subcarrier; the OLT sends a downlink broadcast signal to each subcarrier so as to match a corresponding idle windowing subcarrier for a newly accessed optical network unit ONU; and the OLT receives uplink registration information of the ONU through the idle windowing subcarrier so as to carry out data transmission. Through application of the method and the device, the problems of high time delay and low transmission efficiency during TDM-PON data transmission in related technologies are solved, and the effects of reducing the TDM-PON data transmission time delay and improving the data transmission efficiency are achieved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of communications, and in particular to a data transmission method, storage medium and electronic device of a passive optical network (PON). Background Art

[0002] Traditional Passive Optical Network (PON) networks implement multi-user access based on Time Division Multiplexing (TDM), and use time slicing to implement multiplexing of transmission channels, that is, each signal transmission uses the entire bandwidth of the channel, but can only use a certain time slot. When a user has no data to send, the time slot allocated to the user in the TDM frame can only be idle. Even if other users have data to send all the time, these idle time slots cannot be used, resulting in low utilization of the multiplexed channel. In order to improve channel utilization, Statistical Time Division Multiplexing (STDM) was created. It is a way to allocate media resources on demand. Resources are allocated only when users have data to transmit. If users stop sending data, resources will not be allocated. Therefore, the same multiplexed channel can be used by more users, improving channel utilization.

[0003] However, TDM-PON also has many problems. First, in TDM-PON, multiple users share the same channel in the physical layer through time division. Although they can share bandwidth to the greatest extent, they cannot physically monopolize bandwidth, making it difficult to implement hard pipes on the physical layer. Second, TDM-PON supports uplink data transmission of multiple optical network units (ONUs) on one wavelength channel. In order to detect newly connected or newly powered-on ONUs in time, the optical line terminal (OLT) PON port side needs to open windows regularly so that the new ONUs can complete the registration and ranging processes required to access the OLT. Data frames must be sent in the sending window allocated by the OLT. During the window opening period, all ONUs in normal working state will suspend sending uplink data, resulting in a large delay.

[0004] In summary, in the related art, when performing TDM-PON data transmission, there are problems of high latency and low transmission efficiency. Summary of the invention

[0005] The embodiments of the present invention provide a data transmission method, storage medium and electronic device for a passive optical network (PON) to at least solve the problems of high delay and low transmission efficiency when performing TDM-PON data transmission in the related art.

[0006] According to one embodiment of the present invention, a data transmission method for a passive optical network PON is provided, comprising: an optical line terminal OLT detects the service transmission status of each subcarrier and selects a subcarrier as a windowed subcarrier; the OLT sends a downlink broadcast signal to each subcarrier to match a newly connected optical network unit ONU with a corresponding idle windowed subcarrier; the OLT receives uplink registration information of the ONU through the idle windowed subcarrier to perform data transmission.

[0007] According to yet another embodiment of the present invention, a computer-readable storage medium is provided, in which a computer program is stored, wherein the computer program is configured to execute the steps of any one of the above method embodiments when run.

[0008] According to yet another embodiment of the present invention, there is provided an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0009] Through the present invention, a data transmission method for a passive optical network PON is provided, wherein the service transmission status of each subcarrier is detected by the optical line terminal OLT, and the subcarrier is selected as a windowed subcarrier; the OLT sends a downlink broadcast signal to each subcarrier to match the corresponding idle windowed subcarrier to the newly connected optical network unit ONU; the OLT receives the uplink registration information of the ONU through the idle windowed subcarrier to perform data transmission. The problem of high delay and low transmission efficiency when performing TDM-PON data transmission in the related art is solved, and the effect of reducing the TDM-PON data transmission delay and improving the data transmission efficiency is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a hardware structure block diagram of a computer terminal of a PON data transmission method according to an embodiment of the present invention;

[0011] Figure 2 is a schematic diagram of a multi-subcarrier architecture of a high-speed PON according to an embodiment of the present invention;

[0012] Figure 3 is a flow chart of a data transmission method of a PON according to an embodiment of the present invention;

[0013] Figure 4 is a structural block diagram of a data transmission device of a PON according to an embodiment of the present invention;

[0014] Figure 5 It is a schematic diagram of the principle of the ONU online registration process in the related technology;

[0015] Figure 6 This is a schematic diagram of the distribution of small-bandwidth sub-band ONUs on a frequency band according to a scenario embodiment of the present invention;

[0016] Figure 7 is a flow chart of a data transmission method of a PON according to a scenario embodiment of the present invention;

[0017] Figure 8 is a schematic diagram of the structure of a physical synchronization block PSBd implemented according to the scenario of the present invention;

[0018] Fig. 9 It is a schematic diagram of the downlink FS frame structure implemented according to the scenario of the present invention. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and in combination with the embodiments.

[0020] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0021] The method embodiments provided in the embodiments of the present application can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking running on a computer terminal as an example, Figure 1 FIG. 1 is a hardware structure block diagram of a computer terminal of a PON data transmission method according to an embodiment of the present invention. Figure 1 As shown, the computer terminal may include one or more ( Figure 1 Only one is shown in the figure) a processor 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA) and a memory 104 for storing data, wherein the above-mentioned computer terminal may also include a transmission device 106 and an input / output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the above-mentioned computer terminal. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations are shown.

[0022] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the data transmission method of the PON in the embodiment of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, to implement the above method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0023] The transmission device 106 is used to receive or send data via a network. The specific example of the above network may include a wireless network provided by a communication provider of a computer terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0024] The present application embodiment can be run on Figure 2 In the network architecture shown, Figure 2 is a schematic diagram of a multi-subcarrier architecture of a high-speed PON according to an embodiment of the present invention. Figure 2 As shown, the network architecture includes: optical line terminal OLT, optical distribution network (Optical Distribution Network, ODN), multiple optical network units ONU, among which, the topological structure of PON still adopts point-to-multipoint form. For the multi-subcarrier technology route, there can be multiple ONUs corresponding to one subcarrier form, and each ONU sends data to the OLT upstream in a time division manner (such as ONU1, ONU2); there can also be a single ONU corresponding to a single subcarrier, and send data to the OLT upstream in a frequency division manner (such as ONU3, ONU4); there can also be a single ONU corresponding to multiple subcarriers, as shown in ONU5. The OLT media access control (Medium Access Control, MAC) schedules and allocates ONUs according to the traffic, so that the traffic on each subcarrier is as stable as possible. This architecture classifies different ONUs and allocates them to different subcarriers according to parameters such as reliability and delay requirements, giving full play to the flexible multiplexing advantages of TDM and the hard pipe advantages of FDM, meeting the needs of different applications and different scenarios, and maximizing the use of network resources.

[0025] In this embodiment, a data transmission method of a PON running on the above-mentioned computer terminal or network architecture is provided. Figure 3 is a flow chart of a data transmission method of a PON according to an embodiment of the present invention, such as Figure 3 As shown, the process includes the following steps:

[0026] Step S302, the optical line terminal OLT detects the service transmission status of each subcarrier and selects a subcarrier as a windowing subcarrier;

[0027] In an exemplary embodiment, the OLT detects the service transmission status of each subcarrier and selects a subcarrier as a windowed subcarrier, including: the OLT detects the service transmission status of each subcarrier and selects a subcarrier with the least service transmission as the windowed subcarrier; or the OLT detects the service transmission status of each subcarrier and selects a subcarrier less than or equal to a service transmission threshold as the windowed subcarrier.

[0028] In actual implementation, the service transmission threshold can be set according to experience or actual conditions, and the subcarriers less than or equal to the service transmission threshold are multiple subcarriers. In actual implementation, when the number of subcarriers with the least service transmission is multiple, one of the subcarriers can be selected as the windowing subcarrier.

[0029] In an exemplary embodiment, after selecting a subcarrier as a windowed subcarrier, the method further includes: the OLT detects whether there is a delay-sensitive service on the windowed subcarrier, and if so, migrates the delay-sensitive service to a non-windowed subcarrier with remaining bandwidth in the OLT for transmission.

[0030] In the actual implementation process, the subcarrier selected as the windowed subcarrier may still have service transmission. For the windowed subcarrier with delay-sensitive services, in order to ensure that service transmission is not affected, it is necessary to migrate the delay-sensitive services to the non-windowed subcarrier with remaining bandwidth for transmission. The windowed subcarrier becomes an idle windowed subcarrier, so as to better transmit the service data of the newly connected ONU. In the actual implementation process, if there is no non-windowed subcarrier with remaining bandwidth, the windowed subcarrier with delay-sensitive services can also be directly windowed. Since the subcarrier with the least service transmission in the system is selected as the windowed subcarrier, although the direct windowing operation may affect the services being transmitted, the overall impact on the system can be guaranteed to be minimized.

[0031] In an exemplary embodiment, before the optical line terminal OLT detects the service transmission status of each subcarrier, the method further includes: configuring multiple subcarriers for the optical line terminal OLT, wherein the overhead part in the downstream port physical data frame PHY of each subcarrier is synchronized with each other.

[0032] Step S304, the OLT sends a downlink broadcast signal to each subcarrier to match the corresponding idle windowed subcarrier for the newly connected optical network unit ONU;

[0033] In an exemplary embodiment, matching a corresponding idle windowed subcarrier for a newly connected optical network unit ONU includes: the OLT detects whether the first sub-band of the newly connected optical network unit ONU contains an idle windowed subcarrier; if the detection result is yes, adjusting the ONU to an idle windowed subcarrier within the first sub-band; if the detection result is no, adjusting the first sub-band of the ONU to a second sub-band where an idle windowed subcarrier is located, and the ONU is adjusted to an idle windowed subcarrier within the second sub-band; or, updating the detected idle windowed subcarrier at a fixed time interval so that the ONU matches the corresponding idle windowed subcarrier; or, adjusting the second sub-band and the first sub-band to a third sub-band at the same time, and the ONU is adjusted to an idle windowed subcarrier within the third sub-band.

[0034] In the actual implementation process, the third solution can be regarded as a combination of the first solution and the second solution, because in the third solution, since the system is dynamic, a new idle windowing subcarrier is generated, so that the ONU can successfully match the corresponding idle windowing subcarrier. In fact, it can also be regarded as an adjustment of the waveband of the idle windowing subcarrier, which is not limited here.

[0035] In an exemplary embodiment, the OLT sends a downlink broadcast signal to each subcarrier, including: the OLT uses a synchronously counting superframe counter to send the downlink broadcast signal to each subcarrier.

[0036] In an exemplary embodiment, it also includes: when the first sub-band of the ONU is adjusted to the second sub-band of the idle windowed subcarrier, after the OLT receives the uplink registration information of the ONU through the idle windowed subcarrier, adjusting the ONU from the second sub-band to the first sub-band.

[0037] Step S306: The OLT receives the uplink registration information of the ONU through the idle windowed subcarrier to perform data transmission.

[0038] In an exemplary embodiment, the method further includes: reselecting a new windowing subcarrier according to the service transmission status of each subcarrier to perform data transmission for a newly connected ONU.

[0039] In an exemplary embodiment, after the OLT receives the uplink registration information of the ONU through an idle windowed subcarrier, the method further includes: the ONU sends data to the OLT in a time division multiplexing TDM or frequency division multiplexing FDM manner.

[0040] Through the above steps, a data transmission method for a passive optical network PON is provided, wherein the service transmission status of each subcarrier is detected by the optical line terminal OLT, and a subcarrier that is less than or equal to the service transmission threshold is selected as a window subcarrier; the OLT sends a downlink broadcast signal to each subcarrier to match the corresponding idle window subcarrier to the newly connected optical network unit ONU; the OLT receives the uplink registration information of the ONU through the idle window subcarrier for data transmission. The problem of high delay and low transmission efficiency when performing TDM-PON data transmission in the related technology is solved, and the effect of reducing the TDM-PON data transmission delay and improving the data transmission efficiency is achieved.

[0041] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for enabling a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0042] In this embodiment, a data transmission device of a PON is also provided, which is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made are not repeated here. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0043] Figure 4 is a structural block diagram of a data transmission device of a PON according to an embodiment of the present invention, such as Figure 4 As shown, the data transmission device 40 includes: a service detection module 410, which is used to detect the service transmission status of each subcarrier and select a subcarrier as a windowed subcarrier; a matching module 420, which is used to send a downlink broadcast signal to each subcarrier to match the corresponding idle windowed subcarrier to the newly connected optical network unit ONU; a registration module 430, which is used to receive the uplink registration information of the ONU through the idle windowed subcarrier for data transmission.

[0044] It should be noted that the above modules can be implemented by software or hardware. For the latter, it can be implemented in the following ways, but not limited to this: the above modules are all located in the same processor; or, the above modules are located in different processors in any combination. In the actual implementation process, the above data transmission device can implement each step of the data transmission method in the above embodiment. Therefore, the data transmission device can be divided into modules or units with different functions. There is no specific limitation on the functional division and naming of different modules and units.

[0045] An embodiment of the present invention further provides a computer-readable storage medium, in which a computer program is stored, wherein the computer program is configured to execute the steps of any of the above method embodiments when running.

[0046] In an exemplary embodiment, the computer-readable storage medium may include, but is not limited to, various media that can store computer programs, such as a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk.

[0047] An embodiment of the present invention further provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0048] In an exemplary embodiment, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0049] For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail herein.

[0050] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0051] In order to enable those skilled in the art to better understand the technical solution of the present invention, it is described below in conjunction with specific scenario embodiments.

[0052] Scenario Example 1

[0053] Figure 5 This is a schematic diagram of the principle of the ONU online registration process in the related technology, such as Figure 5 As shown in the figure, when a new ONU goes online to register, since the ONU has not undergone the ranging process, it cannot interact with the online ONUs at the same time, and a special period of time must be prepared for it to go online and register. The interaction process between OLT and ONU will reserve a certain time for the new online ONU to perform the registration process. During this period, all online ONUs in work must temporarily delay transmission. This reserved time is equivalent to opening a registration and ranging window on the data transmission channel. The registration and ranging window is related to the distance of the ONU newly added to the system, which is usually around 250us, and will have a delay effect on the remaining online ONUs. Traditional PON technology adopts the upstream TDM working mode. In order to detect the newly connected ONU in time, the OLT PON port side needs to open the window regularly so that the new ONU can complete the registration, ranging and other processes required to access the OLT. During the window opening period, all ONUs in normal working state suspend sending upstream data, resulting in delay.

[0054] To solve the problems such as long delay in traditional TDM-PON, the multi-subcarrier TFDM designed in the embodiment of the present invention provides the following solution.

[0055] Considering the cost factor of ONU, compared with ONU supporting the entire frequency band, the scenario embodiment of the present invention chooses to use ONU supporting small bandwidth sub-band. This ONU works within a certain range outside its own center frequency to form a sub-band of the ONU on the frequency band. Figure 6 FIG. 4 is a schematic diagram of the distribution of small-bandwidth sub-band ONUs on a frequency band according to a scenario embodiment of the present invention. Figure 6 As shown, for each individual ONU, the frequency band can be sliced ​​equally according to its sub-band size, and a corresponding number of sub-carriers are allocated therein, and the ONU can be distributed in any sub-carrier on the sub-band. In this way, the ONU can only process its own sub-band and ignore the rest of the sub-bands, which helps to achieve flexible ONU downstream and upstream rates. Based on supporting different numbers of sub-carriers, different ONUs can have different maximum capacities.

[0056] Figure 7 is a flow chart of a data transmission method of a PON according to a scenario embodiment of the present invention, such as Figure 7 As shown, the following steps are included:

[0057] 1) In the TFDM multi-subcarrier architecture adopted in the embodiment of the present invention, the OLT detects the service transmission status on each subcarrier in real time, selects the subcarrier with the least service transmission as the windowing subcarrier, and the remaining subcarriers are only used for service transmission without windowing operation.

[0058] In actual implementation, the number of subcarriers selected for least service transmission may be one or more, and may be selected and set according to actual conditions and needs. This is only an example and is not specifically limited.

[0059] 2) Perform windowing operation on these selected windowing subcarriers. If they are all idle windowing subcarriers, directly perform windowing. If there is a service being transmitted on a certain windowing subcarrier, first determine whether the service being transmitted is sensitive to delay. If it is an insensitive service, directly perform windowing operation. If it is a delay-sensitive service, two solutions are proposed: the first is to first detect the non-windowing subcarriers with remaining bandwidth in the system, and migrate the service being transmitted to the non-windowing subcarrier to send, so that the windowing subcarrier becomes idle, and then perform windowing operation; the second is to directly perform windowing operation on the windowing subcarrier. Since the subcarrier with the least service transmission in the system is selected as the windowing subcarrier, even if the direct windowing operation may affect the service being transmitted, the overall impact on the system can be guaranteed to be the lowest.

[0060] 3) The OLT sends a downstream broadcast signal to the ONU on each subcarrier. For each newly connected ONU on each subcarrier, it first detects whether the subband where the ONU is located contains an idle windowed subcarrier. If so, the ONU is adjusted to the windowed subcarrier within the subband (or directly on the windowed subcarrier) and uses the windowed subcarrier channel to send upstream registration information to the OLT.

[0061] 4) If not, continue to detect whether there is any low-latency service being transmitted on each windowed subcarrier in the system. There are three options to choose from: the first is that after finding an idle windowed subcarrier, the OLT maintains the idle windowed subcarrier for windowing operations, and the ONU will first adjust from the subband it is currently in to the subband where the idle windowed subcarrier is located, and then the ONU adjusts to the windowed subcarrier within the new subband, and uses the windowed subcarrier channel to send uplink registration information to the OLT; the second is that the OLT searches for idle windowed subcarriers in the system in turn, and performs a windowing operation and waits for a period of time whenever an idle windowed subcarrier is found. If no ONU is online, it continues to search for the next idle windowed subcarrier. If the ONU happens to appear on an idle windowed subcarrier during this process, the windowed subcarrier channel is directly used to send uplink registration information to the OLT; the third is that the ONU's subband adjustment, subcarrier adjustment, and the OLT's sequential search for idle windowed subcarriers for windowing and waiting are performed simultaneously, so that the ONU uses the windowed subcarrier channel to send uplink registration information to the OLT as soon as possible.

[0062] In the actual implementation process, for the second solution mentioned above, although the "determination that there is no band containing idle windowed subcarriers in the newly connected ONU" has been performed in advance, the distance judgment action has already gone through the OLT's search for idle windowed subcarriers. Given that the system is dynamic, there is a possibility that the ONU happens to appear on the idle windowed subcarrier. Therefore, it is also necessary to search for idle windowed subcarriers at fixed time intervals as described in the second solution. If the ONU happens to appear on an idle windowed subcarrier, the windowed subcarrier channel is directly used to send uplink registration information to the OLT. Among them, the above-mentioned fixed time interval can be set according to actual conditions, and there is no restriction here.

[0063] In the actual implementation process, the third solution can be regarded as a combination of the first solution and the second solution, because in the third solution, since the system is dynamic, a new idle windowing subcarrier is generated, so that the ONU can successfully match the corresponding idle windowing subcarrier. In fact, it can also be regarded as an adjustment of the waveband of the idle windowing subcarrier, which is not limited here.

[0064] 5) After the ONU online registration process is completed, check whether there is any service being transmitted on the windowed subcarrier. If not, the service is directly transmitted on the windowed subcarrier; if so, detect the non-windowed subcarrier with remaining bandwidth in the system and migrate the new service to be transmitted to the non-windowed subcarrier for transmission.

[0065] In the TFDM multi-subcarrier system of the embodiment of the present invention, some subcarriers will be used as windowed subcarriers to perform timed windowing operations, which are responsible for completing the registration, ranging and other processes required for the new ONU to access the OLT. The service will be transmitted on the remaining non-windowed subcarriers to avoid the delay caused by the windowed registration mechanism, so that the service can achieve low-latency and low-jitter transmission effect. In addition, the newly connected ONU can send uplink registration information to the OLT on all idle windowed subcarrier channels at the same time, and the new services that need to be sent can also be transmitted on different subcarriers with bandwidth allocated by the OLT at the same time, thereby improving transmission efficiency.

[0066] In the specific steps of the above embodiment, in step 1), the windowed subcarriers are not always fixed after they are selected, but can be determined in real time according to the number of services being transmitted on each subcarrier. When the windowed subcarriers are selected in step 1), they are the subcarriers with the least service transmission. However, as the transmission service situation changes, the windowed subcarriers may also be occupied by a large number of services, and other non-windowed subcarriers are more idle. At this time, return to step 1) and reselect the windowed subcarriers to ensure that the service transmission of the windowed subcarriers is relatively minimal.

[0067] Scenario Example 2

[0068] In the scenario embodiment, to realize service migration between different subcarriers, it is necessary to configure multiple subcarriers for the optical line terminal OLT, wherein the overhead part in the physical data frame PHY of the downlink port of each subcarrier is synchronized with each other, and the OLT uses a superframe counter with synchronous counting to send a downlink broadcast signal to each subcarrier. In the scenario embodiment 2, how to realize the synchronization of the overhead part in the physical data frame PHY of the downlink port of each subcarrier is introduced in detail.

[0069] The overhead part of the downstream PHY frame. The OLT Channel Termination (CT) is transmitted continuously in the downstream direction. The transmission of the OLT CT is divided into fixed-size downstream PHY frames. The downstream PHY frame consists of a physical synchronization block (PSBd) and a PHY frame payload. The PHY frame payload is represented by a downstream FS frame. The start of a downstream PHY frame corresponds to the transmission (by the OLT CT) or reception (by the ONU) of the first bit of its PSBd.

[0070] Figure 8 is a schematic diagram of the structure of a physical synchronization block PSBd implemented according to the scenario of the present invention, such as Figure 8As shown in the figure, the downstream physical synchronization block PSBd contains three independent structures: the physical synchronization sequence (Physical Synchronization Sequence, PSync), the super frame counter (Super Frame Counter, SFC) structure and the operating control (Operating Control, OC) structure. PSync is a fixed code, and the ONU uses this sequence to achieve alignment at the downstream PHY frame boundary. The SFC structure contains a super frame counter SFC and a HEC field. The HEC field is to protect the SFC structure. The OC structure contains an OC body and a HEC field. The HEC field is to protect the OC structure. The OC body contains a PON-ID structure, which is used to identify the OLT in the domain.

[0071] Fig. 9 Schematic diagram of the downlink FS frame structure implemented according to the scenario of the present invention, such as Fig. 9 As shown, the downstream FS frame consists of a downstream FS frame header and a FS payload. The downstream FS frame header consists of a fixed-size HLend structure and two variable-size partitions: a Band Width Mapped Partition (BWmap) and a downstream Physical Layer Operation and Maintenance Management (PLOAM) partition. HLend is a 4-byte structure used to control the size of the BWmap and PLOAM variable-length partitions in the downstream FS frame header. BWmap is a series of 8-byte allocation structures, each of which specifies the bandwidth allocation for a specific Alloc-ID. A sequence of one or more allocation structures, associated with an Alloc-ID belonging to the same ONU and used for continuous upstream transmission, forms a burst allocation sequence. The OLT CT uses the BWmap partition to allocate upstream transmission opportunities to the ONUs and to each Alloc ID within each ONU. The frequency and size of the allocations to each ONU and each Alloc ID depend on the various service parameters and the current power management mode of each given ONU.

[0072] The PSBd and FS frame header of the downlink PHY frame together constitute the overhead part in the downlink PHY frame, and the starting position in the downlink PHY frame is fixed. For the multi-subcarrier architecture of the embodiment of the present invention, when the aforementioned embodiment 1 is adopted to migrate the service to the non-windowed subcarrier for transmission, the time slot allocated by the OLT to the ONU is also migrated to the non-windowed subcarrier. If the overhead part in the initial downlink PHY frame on the non-windowed subcarrier is not synchronized with the overhead part on the windowed subcarrier, then the migrated time slot may conflict with the overhead part at a fixed position on the non-windowed subcarrier, which requires a subsequent scheduling algorithm to control the transmission time, which will bring additional delays.

[0073] In order to further reduce the overall system delay, the embodiment of the present invention may require the overhead part of the initial downlink PHY frame on each subcarrier to be synchronized. The signal sent by the OLT is clock-synchronized when it arrives at each subcarrier, so that the Psync composed of fixed codes in the overhead part on each subcarrier is sent at the same time, so that the boundaries of the downlink PHY frames of each subcarrier are aligned. At this time, the superframe counter SFC count in the initial superframe on each subcarrier also remains synchronized. This can be achieved through subcarrier adjustment.

[0074] When the overhead part in the initial downlink PHY frame on all subcarriers is synchronized, the service migration can be directly performed by adopting the solution of embodiment 1 without resynchronizing the clock, symbol, etc., so that the service can be switched seamlessly and flexibly, further reducing the overall delay of the system and improving transmission efficiency.

[0075] In summary, the embodiment of the present invention provides a data transmission method for a passive optical network PON, and based on the problems that arise in the evolution of TDM-PON to subsequent high-speed PON, a method for achieving low-latency, high-transmission efficiency time-frequency division multiplexing (TFDM) is implemented. In the high-speed PON system architecture, the use of a multi-subcarrier system architecture has become one of the technical routes with great application potential due to its multiple advantages. For the multi-subcarrier technology route solution, the TFDM of the embodiment of the present invention is equivalent to integrating the frequency division multiplexing (FDM) technology into the TDM architecture: First, under the TFDM multi-subcarrier design, the delay caused by the window registration mechanism is avoided by migrating the service to the remaining subcarriers, thereby reducing the overall system delay; Second, through the introduction of TFDM multi-subcarriers, when the overhead part of the initial downlink PHY frame (PHY frame includes: preamble Preamble data packet header Header Payload) on each subcarrier is synchronized, the service can be directly migrated without the need for additional clock, symbol and other synchronization processes, further reducing the overall system delay and improving transmission efficiency. Automatically selecting the window subcarrier position according to the real-time service transmission situation and the initial subcarrier overhead synchronization are important technical features provided by the embodiment of the present invention. The TFDM architecture based on the multi-subcarrier technology route in the PON field proposed in the embodiment of the present invention further improves the problem of large delay of the architecture, which is helpful for early layout and planning in the direction of high-speed PON technology route selection.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A data transmission method for a passive optical network PON, characterized in that: include: The optical line terminal OLT detects the service transmission status of each subcarrier and selects a subcarrier as a windowing subcarrier; The OLT sends a downlink broadcast signal to each of the subcarriers to match the corresponding idle windowed subcarriers to the newly connected optical network unit ONU; The OLT receives the uplink registration information of the ONU through the idle windowed subcarrier to perform data transmission.

2. The method according to claim 1, characterized in that The optical line terminal OLT detects the service transmission status of each subcarrier and selects a subcarrier as a windowing subcarrier, including: The OLT detects the service transmission status of each subcarrier and selects a subcarrier with the least service transmission as the windowing subcarrier; Alternatively, the OLT detects the service transmission status of each subcarrier, and selects a subcarrier that is less than or equal to a service transmission threshold as the windowed subcarrier.

3. The method according to claim 1, characterized in that After selecting the subcarrier as the windowed subcarrier, the method further includes: The OLT detects whether there is a delay-sensitive service on the windowed subcarrier, and if so, migrates the delay-sensitive service to a non-windowed subcarrier with remaining bandwidth in the OLT for transmission.

4. The method according to claim 1, characterized in that: The matching of the corresponding idle windowed subcarriers for the newly connected optical network unit ONU includes: The OLT detects whether the first sub-band of the newly connected optical network unit ONU contains idle windowed sub-carriers; If the detection result is yes, adjusting the ONU to an idle windowed subcarrier within the first sub-band; If the detection result is negative, the first sub-band of the ONU is adjusted to the second sub-band where the idle windowed subcarrier is located, and the ONU is adjusted to the idle windowed subcarrier within the second sub-band; or, the idle windowed subcarrier is updated and detected at fixed time intervals so that the ONU matches the corresponding idle windowed subcarrier; or, the second sub-band and the first sub-band are adjusted to the third sub-band at the same time, and the ONU is adjusted to the idle windowed subcarrier within the third sub-band.

5. The method according to claim 1, characterized in that Before the optical line terminal OLT detects the service transmission status of each of the subcarriers, the method further includes: A plurality of subcarriers are configured for an optical line terminal OLT, wherein overhead parts in a downlink port physical data frame PHY of each of the subcarriers are synchronized with each other.

6. The method according to claim 1, characterized in that Also includes: According to the service transmission conditions of each of the subcarriers, a new windowing subcarrier is reselected to perform data transmission for the newly connected ONU.

7. The method according to claim 1, characterized in that The OLT sends a downlink broadcast signal to each of the subcarriers, including: The OLT uses a synchronously counting superframe counter to send a downlink broadcast signal to each of the subcarriers.

8. The method according to claim 1, characterized in that After the OLT receives the uplink registration information of the ONU through the idle windowed subcarrier, the method further includes: The ONU sends data to the OLT in a time division multiplexing (TDM) or frequency division multiplexing (FDM) manner.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, wherein the computer program implements the method described in any one of claims 1 to 8 when executed by a processor.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method described in any one of claims 1 to 8 is implemented.

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