Method for measuring distance from PON (Passive Optical Network) port to ONU (Optical Network Unit) equipment

Abstract

The invention relates to the technical field of optical communication networks, in particular to a method for measuring distance from a PON (Passive Optical Network) port to ONU (Optical Network Unit) equipment, which comprises the following steps of: S1, configuring a distance measuring control module at an OLT (Optical Line Terminal) end of a PON network, and carrying out initialized static distance measuring between an ONU and the OLT and dynamic distance measuring in normal communication through a distance measuring technology; s2, measuring the loop delay of a data signal sent from the downlink of the OLT to the uplink of the ONU, wherein a delay compensation mechanism adjusts a sending window in real time; s3, through a temperature sensor and an equipment self-checking function, environment change is monitored in real time, intelligent prediction and preventive maintenance are carried out, and bandwidth allocation and a transmission strategy are automatically adjusted; and S4, viewing the ranging data, bandwidth utilization condition and network state of each ONU, and performing optimal configuration according to maintenance suggestions. The method can improve the bandwidth utilization rate, improve the transmission stability, prevent faults in advance, reduce the maintenance cost and improve the operation and maintenance efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of optical communication networks, and in particular to a distance measurement method from an access optical network PON port to an ONU device. Background Art

[0002] In modern communication networks, especially in Ethernet Passive Optical Networks (EPON) and various PON systems, network efficiency is affected by the physical distance differences between each ONU and OLT and environmental factors. Due to these physical differences and environmental factors (such as temperature changes and equipment aging), upstream data signals often collide, resulting in data packet loss, queue delay growth and other problems, thereby reducing the transmission efficiency and stability of the network. EPON and PON systems transmit data through shared media, and any differences in the physical layer may affect the performance of the entire network.

[0003] Currently, static and dynamic bandwidth allocation algorithms are mainly used in PON systems to manage data transmission. Static bandwidth allocation is based on a preset bandwidth allocation strategy and does not consider the real-time network status and physical distance differences, while simple dynamic bandwidth allocation adjusts bandwidth according to changes in network traffic. These solutions usually rely on fixed time intervals for data transmission and cannot respond to physical layer changes in real time. In addition, some advanced solutions introduce basic ranging technology, but they are mostly used in the initial equipment configuration stage and lack real-time adjustment capabilities. Summary of the invention

[0004] To solve the above problems, the present invention provides a method for measuring the distance from an access optical network PON port to an ONU device, which can improve bandwidth utilization, enhance transmission stability, prevent failures in advance, reduce maintenance costs, and improve operation and maintenance efficiency.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for measuring the distance from an access optical network PON port to an ONU device comprises the following steps:

[0007] S1: Configure the ranging control module at the OLT end of the PON network, initiate the ranging signal and collect the returned data, and use the ranging technology to perform the initial static ranging between the ONU and OLT and the dynamic ranging in normal communication;

[0008] S2: Measure the loop delay of the data signal sent from the OLT downstream to the ONU upstream, adjust the authorization time window in the DBA algorithm according to the measurement results, and dynamically adjust the ONU's sending window according to the ranging data. The delay compensation mechanism adjusts the sending window in real time;

[0009] S3: Through temperature sensors and device self-checking functions, it monitors environmental changes in real time, intelligently predicts and performs preventive maintenance, and automatically adjusts bandwidth allocation and transmission strategies;

[0010] S4: Check the ranging data, bandwidth utilization and network status of each ONU, and optimize the configuration according to the maintenance recommendations.

[0011] Furthermore, the distance measurement control module includes: an optical transmitter, an optical receiver, a clock source and a timer, a signal processing unit and a data storage unit;

[0012] The optical transmitter comprises a driving circuit and a light source using a semiconductor laser;

[0013] The optical receiver includes a photodetector, a preamplifier, a main amplifier and an equalizer;

[0014] The clock source and timer include high-precision clock source and timer circuits;

[0015] The signal processing unit includes a digital signal processor or a field programmable gate array, and an algorithm module.

[0016] Furthermore, the distance measurement technology includes: an in-band windowing method, an out-of-band method or a spread spectrum method;

[0017] The in-band windowing method includes inserting a specific ranging signal inside the data transmission window and measuring the distance using its return time;

[0018] The out-of-band method includes transmitting a ranging signal through a frequency band, and performing ranging with a signal in a non-data transmission frequency band;

[0019] The spread spectrum method includes performing precise ranging using signals generated by spread spectrum technology.

[0020] Furthermore, the initialization of static ranging includes the following steps:

[0021] When the ONU registers with the OLT, the OLT device is started and the ranging control module is initialized. The signal processing unit generates an initialization ranging authorization message according to the system configuration. The optical transmitter converts this message into an optical signal and sends it to the PON network at the set wavelength and power.

[0022] After receiving the initial ranging authorization message, the ONU starts to prepare for a response after a random short delay based on its own processing capability and internal delay characteristics. The ONU generates a ranging request message containing its own identification information and converts it into an optical signal and sends it back to the OLT.

[0023] The optical receiver receives the ranging request optical signal returned by the ONU, and after photoelectric conversion, amplification and equalization processing, transmits the electrical signal to the signal processing unit. The signal processing unit calculates the preliminary distance value based on the time of sending the initialization ranging authorization message and the time of receiving the ranging request message recorded by the clock source and the timer, and stores this distance value and the identification information of the ONU in the data storage unit.

[0024] Furthermore, the dynamic ranging in normal communication includes the following steps:

[0025] According to a preset time interval or when a specific event is detected, the signal processing unit triggers a dynamic ranging operation, the signal processing unit of the ranging control module generates a precise ranging authorization message according to the current network status and historical information in the database, and the optical transmitter converts the precise ranging authorization message into an optical signal and sends it to the PON network;

[0026] After receiving the precise ranging authorization message, the ONU adjusts its transmission timing according to the instructions in the message, regenerates the ranging request message containing the updated information, converts it into an optical signal and sends it back to the OLT. The optical receiver receives the ranging request optical signal returned by the ONU, and after optical-electrical conversion, amplification and equalization processing, transmits the signal to the signal processing unit;

[0027] The signal processing unit again calculates the updated distance value based on the time information recorded by the clock source and the timer, compares the new distance value with the original data in the basic time delay database, and analyzes the distance change. If the distance change exceeds a certain threshold, the relevant time delay data in the database is updated. At the same time, the signal processing unit passes the new distance information to the unit working with the DBA.

[0028] Further, the loop delay of the data signal sent from the OLT downstream to the ONU upstream is measured, the authorization time window in the DBA algorithm is adjusted according to the measurement result, the sending window of the ONU is dynamically adjusted according to the ranging data, and the delay compensation mechanism adjusts the sending window in real time; including the following steps:

[0029] S21: When sending a downlink data signal, the ranging control module of the OLT embeds tag information containing a timestamp in the signal. After receiving the downlink data signal with the tag information, the ONU extracts the timestamp and records the time of receiving the signal.

[0030] S22: When the ONU sends uplink data, it adds the information including the timestamp and the receiving time to the uplink data frame and sends it back to the OLT. The optical receiver of the OLT receives the uplink data frame sent back by the ONU. The signal processing unit in the ranging control module extracts the timestamp and the receiving time from the frame, and records the time when the uplink data frame is received, and calculates the loop delay.

[0031] S23: The signal processing unit compares and analyzes the calculated loop delay with the historical loop delay data previously stored in the data storage unit, and if there is a change, adjusts the authorization time window in the DBA algorithm;

[0032] S24: Real-time monitoring of various parameters in the network as feedback information for whether the adjustment of the sending window is effective. By continuously repeating the process of ranging, calculation and adjustment, real-time dynamic adjustment of the ONU sending window is achieved to compensate for the delay changes caused by various factors.

[0033] Furthermore, the adjustment of the authorization time window in the DBA algorithm includes:

[0034] If the loop delay increases and there are a large number of real-time services in the network, adopt a strategy of increasing the authorization time window and reducing the impact on existing services;

[0035] If the loop delay increases but the network is mainly used for non-real-time data download services, increase the authorization time window and adjust the proportion of allocated bandwidth;

[0036] If the loop delay is reduced, the authorization time window can be shortened without affecting the normal data transmission of the ONU;

[0037] The increasing of the authorization time window includes adjusting the DBA algorithm based on polling and adjusting the DBA algorithm based on bandwidth prediction.

[0038] Furthermore, the method uses temperature sensors and equipment self-checking functions to monitor environmental changes in real time, intelligently predict and preventive maintenance, and automatically adjust bandwidth allocation and transmission strategies; including the following steps:

[0039] S31: Install temperature sensors and humidity sensors in the PON network equipment, regularly check various components of the equipment through the equipment self-check function, record the equipment's operating time, service flow data, and historical fault record data, and pre-process the collected temperature, humidity, equipment operating parameters, and service flow data;

[0040] S32: Select features related to fault prediction and performance degradation from the preprocessed data, build a decision tree model using the CART algorithm, randomly select preprocessed historical data as a training set, and mark them according to different fault types and performance degradation indicators during the training process so that the model can learn the relationship between data features and faults or performance degradation. Evaluate and optimize the model using the test set.

[0041] S33: The real-time collected and pre-processed environment and device status data are input into the trained model. The model predicts whether a failure or performance degradation is likely to occur based on the input data. When the model predicts a possible failure or performance degradation, the early warning mechanism is triggered and the bandwidth allocation and transmission strategy are automatically adjusted.

[0042] Furthermore, the automatic adjustment of bandwidth allocation and transmission strategy includes the following steps:

[0043] S331: When the model predicts a failure or performance degradation, the affected ONUs and the types of services running on the ONUs are analyzed, the impact of the bandwidth requirements of each affected ONU is evaluated, the total available bandwidth resources of the PON network are obtained from the configuration information of the OLT, the bandwidth currently allocated to each ONU is queried in the database, and the remaining available bandwidth is calculated;

[0044] S332: Allocate additional bandwidth according to the priority of the services on the affected ONUs. For each affected ONU, allocate bandwidth according to the previously evaluated impact of bandwidth demand. If the additional bandwidth demand of the affected ONU exceeds the remaining available bandwidth, it is necessary to adjust the bandwidth of other unaffected ONUs. Update the adjusted bandwidth allocation value of each ONU to the relevant parameters of the DBA algorithm, and the dynamic broadband allocation starts to implement a new bandwidth allocation plan according to the updated parameters.

[0045] S333: Determine the type of transmission problem that occurs according to the prediction result, analyze the impact on the transmission and reception timing strategy of the ONU according to the increase in the processing delay of the signal processing unit, if it is predicted that the signal transmission is affected due to the increase in optical fiber loss, calculate the transmission power that needs to be increased, and the optical transmitter adjusts the transmission power according to the calculated transmission power value, if it is predicted that the internal processing delay of the ONU increases or the timing relationship in the network changes, adjust the transmission window of the ONU, if it is predicted that the characteristics of the optical signal change, adjust the relevant parameters of the optical receiver of the ONU, if the transmission wavelength changes, adjust the filter center wavelength of the optical receiver;

[0046] S334: The OLT sends an adjustment instruction to each related ONU. The instruction includes the adjusted parameter information of the optical transmitter and the sending and receiving strategy parameters that the ONU itself needs to adjust. The performance indicators of the network are continuously monitored for a period of time after the adjustment. If the network performance is improved, the current adjustment strategy is maintained. If the network performance does not improve or deteriorates, the prediction results and adjustment strategy are re-evaluated.

[0047] Further, the checking of each ONU ranging data, bandwidth utilization and network status, and optimizing configuration according to maintenance suggestions comprises the following steps:

[0048] S41: In the OLT device, the ranging data, bandwidth utilization and network status are collected and stored in the MySQL database of the OLT device. A Web-based visualization interface is constructed through the OLT device to display the ranging data, bandwidth utilization and network status;

[0049] S42: A maintenance suggestion generation mechanism based on predefined thresholds and network best practices is set up in the network management system. Maintenance suggestions are displayed in a separate area of ​​the visual interface. Each maintenance suggestion clearly points out the problem, cause, and recommended action, and is sorted according to priority.

[0050] S43: A configuration operation entry is provided in the visual interface, allowing the operation and maintenance personnel to optimize the configuration of the PON network. The configuration operation entry is restricted by authority management. The operation and maintenance personnel optimize the network configuration according to the maintenance suggestions. After the configuration operation is performed, the network management system records the operation log.

[0051] The beneficial effects of the present invention are:

[0052] 1. Through dynamic ranging and adjustment of the authorization time window in the DBA algorithm based on the ranging results, bandwidth can be accurately allocated according to the actual distance between each ONU and OLT and the real-time status of the network. It avoids bandwidth waste or insufficient bandwidth of some ONUs caused by traditional fixed allocation methods, thereby improving the bandwidth utilization of the entire PON network. Intelligent prediction of failures and performance degradation and automatic adjustment of bandwidth allocation enable the network to respond to possible problems in advance, avoid network congestion caused by insufficient bandwidth, and further optimize the allocation of bandwidth resources.

[0053] 2. Real-time ranging and dynamic adjustment of the ONU transmission window based on ranging data compensate for changes in signal transmission delays caused by environmental changes, equipment aging, etc., ensuring that data reaches the OLT in the correct time slot, reducing data conflicts and transmission errors, and improving the stability of network transmission. Automatic adjustment of relevant parameters of optical transmitters and ONU receivers can cope with signal transmission quality problems caused by environmental changes or equipment performance degradation, ensuring stable and reliable signal transmission.

[0054] 3. Collect data with the help of temperature sensors and equipment self-checking functions, and predict possible failures and performance degradation through machine learning algorithms. This enables operation and maintenance personnel to take measures before failures occur, avoiding the impact on user services when failures occur. Potential performance degradation problems can be discovered in advance and alleviated by adjusting bandwidth allocation or transmission strategies, thereby extending the normal operation time of the equipment and reducing the possibility of network interruptions. Accurate fault prediction helps reduce the number of on-site maintenance. Operation and maintenance personnel perform targeted maintenance based on the prediction results, avoiding unnecessary on-site inspections and troubleshooting, and reducing labor and transportation costs.

[0055] 4. Operation and maintenance personnel can quickly view the ranging data, bandwidth utilization and network status of each ONU through an intuitive visual interface, without the need for complex command line operations or searching for information from a large number of log files, enabling operation and maintenance personnel to locate problems more quickly and save troubleshooting time. The rich data displayed on the visual interface and the maintenance suggestions generated based on the data provide operation and maintenance personnel with a comprehensive decision-making basis. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 The present invention is a schematic diagram of a distance measurement method from an access optical network PON port to an ONU device.

[0057] Figure 2 The invention discloses a flow chart of a distance measurement method from an access optical network PON port to an ONU device. DETAILED DESCRIPTION

[0058] See also Figure 1 As shown, the present invention relates to a method for measuring the distance from an access optical network PON port to an ONU device, comprising the following steps:

[0059] S1: Configure the ranging control module at the OLT end of the PON network, initiate the ranging signal and collect the returned data, and use the ranging technology to perform the initial static ranging between the ONU and OLT and the dynamic ranging in normal communication;

[0060] S2: Measure the loop delay of the data signal sent from the OLT downstream to the ONU upstream, adjust the authorization time window in the dynamic broadband allocation (DBA) algorithm according to the measurement results, and dynamically adjust the ONU's sending window according to the ranging data. The delay compensation mechanism adjusts the sending window in real time;

[0061] S3: Through temperature sensors and device self-checking functions, it monitors environmental changes in real time, intelligently predicts and performs preventive maintenance, and automatically adjusts bandwidth allocation and transmission strategies;

[0062] S4: Check the ranging data, bandwidth utilization and network status of each ONU, and optimize the configuration according to the maintenance recommendations.

[0063] Furthermore, the distance measurement control module includes: an optical transmitter, an optical receiver, a clock source and a timer, a signal processing unit and a data storage unit;

[0064] The optical transmitter comprises a driving circuit and a light source using a semiconductor laser;

[0065] The optical receiver includes a photodetector, a preamplifier, a main amplifier and an equalizer;

[0066] The clock source and timer include high-precision clock source and timer circuits;

[0067] The signal processing unit includes a digital signal processor or a field programmable gate array, and an algorithm module.

[0068] Specifically, the driving circuit generates a suitable electrical signal to drive the light source according to the control signal. For example, in an EPON or GPON system, the driving circuit generates a corresponding electrical pulse signal according to specific transmission rate and signal format requirements. The light source usually uses a semiconductor laser (such as FP-LD or DFB-LD) as a light source. These lasers have specific wavelength characteristics. For example, in GPON, the wavelength of the downstream signal is 1490nm. The light source in the optical transmitter must be able to stably emit light of this wavelength and have a certain power stability and spectral purity to ensure the quality of the ranging signal.

[0069] The photodetector is usually a PIN photodiode or an avalanche photodiode. The preamplifier is used to amplify the electrical signal output by the photodetector, because the electrical signal is very weak. The preamplifier needs to have low noise characteristics to avoid introducing too much noise and affecting the detection of the signal, such as a low-noise field effect transistor (FET) amplifier. The main amplifier and equalizer are used to further amplify the signal to a suitable level, and the equalizer is used to compensate for the distortion of the signal caused by the frequency characteristics during the optical fiber transmission process.

[0070] The high-precision clock source is an oven-controlled crystal oscillator (OCXO) or an atomic clock source. In the process of ranging, it is necessary to accurately measure the sending and receiving time of the signal. The high-precision clock source provides a reference for the entire time measurement. The timer circuit is based on the clock signal generated by the clock source. The timer circuit accurately records the sending and receiving time of the ranging signal; the timer circuit is implemented by a logic circuit such as a counter, and the time interval is determined by counting the clock pulses, and can achieve a time resolution of nanoseconds or even higher.

[0071] The digital signal processor (DSP) or field programmable gate array (FPGA) is responsible for processing the electrical signal received from the optical receiver and the time information obtained by interacting with the clock source and the timer. The DSP or FPGA has a powerful digital signal processing capability and can perform signal filtering, decoding and other operations. The algorithm module includes a ranging algorithm and an algorithm that cooperates with the DBA. The ranging algorithm calculates the distance between the OLT and the ONU based on the round-trip time of the signal.

[0072] It also includes a random access memory (RAM) or a flash memory (Flash) for storing various data in the ranging process, such as the ranging history data of each ONU, relevant parameters for working with the DBA, etc.

[0073] Furthermore, the distance measurement technology includes: an in-band windowing method, an out-of-band method or a spread spectrum method;

[0074] The in-band windowing method includes inserting a specific ranging signal inside the data transmission window and measuring the distance using its return time;

[0075] The out-of-band method includes transmitting a ranging signal through a frequency band, and performing ranging with a signal in a non-data transmission frequency band;

[0076] The spread spectrum method includes performing precise ranging using signals generated by spread spectrum technology.

[0077] Specifically, the in-band windowing method is a method for ranging through in-band signals of normal communication in the PON network. In the normal data transmission frequency band of the PON system, a specific time window or a specific signal format is opened for ranging operations, and the algorithm module of the ranging control module must be able to identify ranging-related information in the in-band windowing signal. In the in-band windowing method, the windowing signal sent by the OLT may contain special coding or timestamp information, and the algorithm module needs to have a corresponding decoding algorithm to extract this information to accurately calculate the distance. At the same time, the algorithm module must consider how to accurately measure the round-trip time under the interference of in-band signals of normal communication based on the characteristics of the in-band windowing method.

[0078] The out-of-band method measures distance through signals different from the normal communication frequency band of the PON network, usually through signals of a special wavelength or frequency range, to avoid mutual interference between the ranging signal and the normal communication signal. The algorithm module of the ranging control module shall control the generation and transmission parameters of the out-of-band signal, such as determining the appropriate wavelength, power and other parameters of the out-of-band signal, to ensure that the out-of-band signal can be effectively transmitted in the PON network and accurately received and identified by the ONU. At the receiving end, the algorithm module shall adopt a receiving and processing algorithm that matches the characteristics of the out-of-band signal. And because the out-of-band signal is separated from the normal communication signal frequency band, the algorithm module can use a relatively independent time measurement and calculation method when calculating the distance, without considering the interference of the in-band signal, and can more accurately measure the round-trip time to calculate the distance.

[0079] The spread spectrum method improves the accuracy and anti-interference ability of ranging by expanding the spectrum of the ranging signal. The spread spectrum signal has a lower power spectrum density and can better resist noise and multipath interference. At the transmitting end, the algorithm module of the ranging control module performs spread spectrum processing on the original ranging signal according to the spread spectrum algorithm (such as the pseudo-random code sequence in the direct sequence spread spectrum) to increase the bandwidth of the signal. At the receiving end, the algorithm module uses the corresponding despreading algorithm to restore the ranging signal. When calculating the distance, the algorithm module in the spread spectrum method needs to consider the influence of the spread spectrum and despreading process on the signal time measurement. At the same time, the algorithm module of the spread spectrum method must also be able to handle the special situation of the spread spectrum signal in a multipath environment, and remove the influence of multipath interference on the ranging result through the relevant algorithm to improve the accuracy of the ranging.

[0080] Furthermore, the initialization of static ranging includes the following steps:

[0081] When the ONU registers with the OLT, the OLT device is started and the ranging control module is initialized. The signal processing unit generates an initialization ranging authorization message according to the system configuration. The optical transmitter converts this message into an optical signal and sends it to the PON network at the set wavelength and power.

[0082] Specifically, the initialization includes: self-checking and parameter setting of related devices and modules such as optical transmitters, optical receivers, clock sources and timers, and signal processing units, such as setting the transmission power and wavelength of the optical transmitter, and initializing the clock source to ensure accurate time measurement. The authorization message contains information for time synchronization, such as a timestamp, so that the ONU can perform ranging responses based on this.

[0083] After receiving the initial ranging authorization message, the ONU starts to prepare for a response after a random short delay based on its own processing capability and internal delay characteristics. The ONU generates a ranging request message containing its own identification information and converts it into an optical signal and sends it back to the OLT.

[0084] Specifically, the random delay is to avoid signal conflicts caused by simultaneous responses of multiple ONUs.

[0085] The optical receiver receives the ranging request optical signal returned by the ONU, and after photoelectric conversion, amplification and equalization processing, transmits the electrical signal to the signal processing unit. The signal processing unit calculates the preliminary distance value based on the time of sending the initialization ranging authorization message and the time of receiving the ranging request message recorded by the clock source and the timer, and stores this distance value and the identification information of the ONU in the data storage unit.

[0086] Specifically, the calculation of the preliminary distance value includes: ranging authorization message time (t 1 ) and the time of receiving the ranging request message (t 2 ), according to the formula: Where v is the propagation speed of light in the optical fiber, which is about 2×10 8 m / s.

[0087] Furthermore, the dynamic ranging in normal communication includes the following steps:

[0088] According to a preset time interval or when a specific event is detected, the signal processing unit triggers a dynamic ranging operation, the signal processing unit of the ranging control module generates a precise ranging authorization message according to the current network status and historical information in the database, and the optical transmitter converts the precise ranging authorization message into an optical signal and sends it to the PON network;

[0089] Specifically, the specific events include network performance degradation, abnormal device temperature, and other events that may be related to environmental changes or device aging. The precise ranging authorization message includes an instruction to adjust the timing of sending the ONU and related parameters for precise ranging.

[0090] After receiving the precise ranging authorization message, the ONU adjusts its own transmission timing according to the instructions in the message, and regenerates the ranging request message containing the updated information, and then converts it into an optical signal and sends it back to the OLT. The optical receiver receives the ranging request optical signal returned by the ONU, and after optical-electrical conversion, amplification and equalization processing, transmits the signal to the signal processing unit;

[0091] The signal processing unit again calculates the updated distance value based on the time information recorded by the clock source and the timer, compares the new distance value with the original data in the basic time delay database, and analyzes the distance change. If the distance change exceeds a certain threshold, the relevant time delay data in the database is updated. At the same time, the signal processing unit passes the new distance information to the unit working with the DBA.

[0092] Specifically, the signal processing unit transmits the new distance information to the unit working in cooperation with the DBA, so that the DBA can adjust the bandwidth allocation strategy for the ONU according to the distance change to ensure the stability of network performance.

[0093] Further, the loop delay of the data signal sent from the OLT downstream to the ONU upstream is measured, the authorization time window in the DBA algorithm is adjusted according to the measurement result, the sending window of the ONU is dynamically adjusted according to the ranging data, and the delay compensation mechanism adjusts the sending window in real time; including the following steps:

[0094] S21: When sending a downlink data signal, the ranging control module of the OLT embeds tag information containing a timestamp in the signal. After receiving the downlink data signal with the tag information, the ONU extracts the timestamp and records the time of receiving the signal.

[0095] S22: When the ONU sends uplink data, it adds the information including the timestamp and the receiving time to the uplink data frame and sends it back to the OLT. The optical receiver of the OLT receives the uplink data frame sent back by the ONU. The signal processing unit in the ranging control module extracts the timestamp and the receiving time from the frame, and records the time when the uplink data frame is received, and calculates the loop delay.

[0096] Specifically, the loop delay is calculated by calculating the difference between the time of the uplink data frame and the timestamp to obtain the loop delay.

[0097] S23: The signal processing unit compares and analyzes the calculated loop delay with the historical loop delay data previously stored in the data storage unit, and if there is a change, adjusts the authorization time window in the DBA algorithm;

[0098] Specifically, the DBA algorithm adjustment is to adjust the authorization time window with the DBA collaborative working unit according to the change of the loop delay. If the loop delay increases, it means that the signal transmission delay increases. In order to ensure that the ONU has enough time to send data without conflicting with other ONUs, the authorization time window needs to be appropriately increased. The specific adjustment strategy can perform different operations according to the type of DBA algorithm (such as based on polling, based on bandwidth prediction, etc.).

[0099] The signal processing unit in the ranging control module continuously monitors the distance data between the ONU (from the results of static ranging and dynamic ranging). If the distance is found to have changed (such as the change in fiber length caused by fiber aging, temperature change, etc., or the change in internal processing delay of the device), the corresponding time delay change Δt is calculated according to the distance change. Since the relationship between distance d and time t is d=vt / 2 (v is the propagation speed of light in the optical fiber), the formula is: Where Δd is the distance change. The ONU's send window is adjusted based on the calculated Δt. If the distance increases, it means that the signal transmission time becomes longer, and the ONU's send window needs to be delayed by Δt; if the distance decreases, the send window is advanced by Δt. This is achieved by sending a message containing a send window adjustment instruction to the ONU. After receiving the instruction, the ONU adjusts its own send timing as required.

[0100] S24: Real-time monitoring of various parameters in the network as feedback information for whether the adjustment of the sending window is effective. By continuously repeating the process of ranging, calculation and adjustment, real-time dynamic adjustment of the ONU sending window is achieved to compensate for the delay changes caused by various factors.

[0101] Specifically, the various parameters, including signal strength, bit error rate, etc., if the network performance indicators are not improved or deteriorate after adjusting the sending window, it is necessary to re-evaluate the ranging data or adjust the adjustment strategy.

[0102] Furthermore, the adjustment of the authorization time window in the DBA algorithm includes:

[0103] If the loop delay increases and there are a large number of real-time services in the network, adopt a strategy of increasing the authorization time window and reducing the impact on existing services;

[0104] If the loop delay increases but the network is mainly used for non-real-time data download services, increase the authorization time window and adjust the proportion of allocated bandwidth;

[0105] If the loop delay is reduced, the authorization time window can be shortened without affecting the normal data transmission of the ONU:

[0106] The increasing of the authorization time window includes adjusting the DBA algorithm based on polling and adjusting the DBA algorithm based on bandwidth prediction.

[0107] Specifically, the real-time services include voice calls or high-definition video live broadcasts.

[0108] The polling-based DBA algorithm adjustment includes: if it is determined that the authorization time window needs to be increased, for the polling-based DBA algorithm, appropriately extending the polling cycle. For example, if the original polling cycle is 1 millisecond, according to the loop delay change ΔT loop , and the number of ONUs in the network N, calculate a new polling period T new , T new =T original +ΔT loop ×k, where T originalis the original polling period, k is a coefficient determined based on experience or network simulation, and its value range may be between 0.1 and 1. At the same time, the authorization duration of each ONU also needs to be adjusted. If there are n ONUs in the network and the total available bandwidth is B, according to the historical bandwidth usage of each ONU, B i (i=1,2,...,n) and the current service demand, reallocate the authorization time T of each ONU i For example, if the service demand of a certain ONUj increases and the loop delay has a greater impact on it, its authorization time T can be increased. j , T j =T j-original +ΔT loop ×m, where T j-original is the original authorization duration of the ONU, and m is another coefficient determined according to the service type and network status, with a value range of 0.05-0.5.

[0109] The DBA algorithm adjustment based on bandwidth prediction includes that if the DBA algorithm based on bandwidth prediction is adopted, the change of loop delay will affect the accuracy of bandwidth prediction. According to the new loop delay data, the relevant parameters in the bandwidth prediction model are updated. For example, in a model based on historical traffic data and linear regression to predict bandwidth, the loop delay is added to the model as a new variable, and the coefficients of the prediction equation are recalculated. According to the updated bandwidth prediction model, the bandwidth requirements of each ONU are re-evaluated. For ONUs that are greatly affected by loop delay and whose service requirements are real-time, their bandwidth allocation ratio is increased. Assume that the predicted bandwidth requirement of ONUk is B k-new , the original bandwidth allocation is B k-original , then the new bandwidth allocation B k-new =B k-original +ΔB, where ΔB is determined based on factors such as the change in loop delay, service type, and total available bandwidth of the network.

[0110] Furthermore, the method uses temperature sensors and equipment self-checking functions to monitor environmental changes in real time, intelligently predict and preventive maintenance, and automatically adjust bandwidth allocation and transmission strategies; including the following steps:

[0111] S31: Install temperature sensors and humidity sensors in the PON network equipment, regularly check various components of the equipment through the equipment self-check function, record the equipment's operating time, service flow data, and historical fault record data, and pre-process the collected temperature, humidity, equipment operating parameters, and service flow data;

[0112] Specifically, the temperature sensor and humidity sensor, these temperature sensors can monitor the temperature changes of the environment in which the equipment is located in real time, and send the temperature data to the management module of the equipment regularly, and collect data through the humidity sensor, and the data collection frequency is the same as the temperature data. The various components include optical transmitters, optical receivers, signal processing units, etc. The equipment self-test function can check the working parameters of the components, such as the transmission power of the optical transmitter, the receiving sensitivity of the optical receiver, etc. The business traffic data includes the upstream and downstream traffic, total traffic, etc. of each ONU. The preprocessing includes: cleaning the collected data such as temperature, humidity, equipment working parameters, business traffic, etc., and removing outliers. The missing data is supplemented by interpolation. The Z-score standardization method is used to standardize data of different magnitudes to facilitate the processing of machine learning algorithms.

[0113] S32: Select features related to fault prediction and performance degradation from the preprocessed data, build a decision tree model using the CART algorithm, randomly select preprocessed historical data as a training set, and mark them according to different fault types and performance degradation indicators during the training process so that the model can learn the relationship between data features and faults or performance degradation. Evaluate and optimize the model using the test set.

[0114] Specifically, the features include: selecting temperature, equipment operation time, working parameters of specific components (such as the bit error rate of the optical receiver), etc. as features, while some data with low relevance to the prediction target (such as certain fixed equipment identification information) can be excluded. Different types of faults in the training process include power drop failure of the optical transmitter due to excessive temperature, performance degradation of the signal processing unit due to long-term operation of the equipment, etc. The performance degradation indicators include reduced network throughput, increased bit error rate, etc. The evaluation includes evaluation indicators such as accuracy, recall rate, F1--Score, etc. If the performance of the model does not meet the requirements, the model is optimized. The optimization method includes adjusting the parameters of the model and using feature engineering to further optimize the feature selection.

[0115] S33: The real-time collected and pre-processed environment and device status data are input into the trained model. The model predicts whether a failure or performance degradation is likely to occur based on the input data. When the model predicts a possible failure or performance degradation, the early warning mechanism is triggered and the bandwidth allocation and transmission strategy are automatically adjusted.

[0116] Specifically, the triggering of the early warning mechanism includes sending early warning information to the network administrator, and recording the early warning event in the equipment management system, including the predicted fault type, possible occurrence time, related data characteristics and other information.

[0117] Furthermore, the automatic adjustment of bandwidth allocation and transmission strategy includes the following steps:

[0118] S331: When the model predicts a failure or performance degradation, the affected ONUs and the types of services running on the ONUs are analyzed, the impact of the bandwidth requirements of each affected ONU is evaluated, the total available bandwidth resources of the PON network are obtained from the configuration information of the OLT, the bandwidth currently allocated to each ONU is queried in the database, and the remaining available bandwidth is calculated;

[0119] Specifically, if it is predicted that the affected ONU is due to the excessive temperature near a certain optical splitter, which may affect the quality of the received signal of some ONUs, the specific ONUs are determined through the topological structure information and device connection relationship of the PON network. The type of service running on the ONU includes querying the service configuration information recorded in the OLT to determine whether the video service, voice service or data service is dominant, and whether there is a service with special requirements for bandwidth and delay. The evaluation of the impact, for example, if it is predicted that the sensitivity of the optical receiver of a certain ONU decreases, it may cause an increase in the bit error rate, thereby affecting the effective transmission of data. According to historical data and empirical models, the increase in the data retransmission rate that may be caused by the increase in the bit error rate is calculated, and then the proportion of bandwidth that needs to be increased is determined. Assuming that the data transmission of the ONU normally requires a bandwidth of 10Mbps, due to the increase in the bit error rate, an additional 20% bandwidth, i.e., 12Mbps, may be required.

[0120] S332: Allocate additional bandwidth according to the priority of the services on the affected ONUs. For each affected ONU, allocate bandwidth according to the previously evaluated impact of bandwidth demand. If the additional bandwidth demand of the affected ONU exceeds the remaining available bandwidth, it is necessary to adjust the bandwidth of other unaffected ONUs. Update the adjusted bandwidth allocation value of each ONU to the relevant parameters of the DBA algorithm, and the dynamic broadband allocation starts to implement a new bandwidth allocation plan according to the updated parameters.

[0121] Specifically, the additional bandwidth is allocated according to the priority of the service on the affected ONU. If there are multiple affected ONUs, the ONU with high service priority will first obtain bandwidth increase. The bandwidth adjustment includes a way of reducing the bandwidth of other ONUs in proportion. For example, the unaffected ONU4 and ONU5 were originally allocated 200Mbps and 150Mbps bandwidth respectively. According to their service flow usage and priority, their bandwidth is reduced according to a certain proportion (such as setting different weight coefficients according to service priority). Another way is to adjust according to the real-time flow demand of the service. If the service flow of a certain unaffected ONU6 is at a low point at the current moment, even if its service priority is high, its part of the bandwidth can be appropriately reduced to give priority to meeting the needs of the affected ONU. The implementation of the new bandwidth allocation scheme includes sending a control message containing new bandwidth allocation information to each ONU, notifying the ONU to transmit data according to the new bandwidth limit in the next communication.

[0122] S333: Determine the type of transmission problem that occurs according to the prediction result, analyze the impact on the transmission and reception timing strategy of the ONU according to the increase in the processing delay of the signal processing unit, if it is predicted that the signal transmission is affected due to the increase in optical fiber loss, calculate the transmission power that needs to be increased, and the optical transmitter adjusts the transmission power according to the calculated transmission power value, if it is predicted that the internal processing delay of the ONU increases or the timing relationship in the network changes, adjust the transmission window of the ONU, if it is predicted that the characteristics of the optical signal change, adjust the relevant parameters of the optical receiver of the ONU, if the transmission wavelength changes, adjust the filter center wavelength of the optical receiver;

[0123] Specifically, the analysis of the impact on the ONU's sending and receiving timing strategy includes adjusting the start time and duration of the ONU's sending window to ensure that its data can arrive correctly within the time slot allocated by the OLT. If the change in the fiber's refractive index affects the optical signal transmission speed, it is necessary to consider the adjustment requirements for the optical transmitter's transmission power, wavelength and other parameters as well as the ONU's receiving sensitivity. The calculation of the required increase in transmission power is based on the fiber loss model and the predicted loss increase value, according to the fiber loss formula L = α × L f , where L is the total loss, α is the loss coefficient, L f Given the fiber length and the predicted loss increase, combined with the power-loss-distance relationship curve of the optical transmitter, determine the transmit power value AP that needs to be increased. If it is predicted that the dispersion characteristics in the optical fiber may have a serious impact on signal transmission due to environmental changes, consider adjusting the transmit wavelength of the optical transmitter. According to the dispersion characteristic curve of the optical fiber and the predicted dispersion change, select a more suitable transmit wavelength.

[0124] The adjustment of the ONU's sending window requires calculating the adjustment amount of the sending window, based on the predicted processing delay increase Δt d , according to the formula (Considering round-trip transmission) calculate the amount of time Δt that the ONU's sending window needs to be delayed. The adjustment of the ONU's optical receiver related parameters, for example, when the transmission power of the optical transmitter increases, in order to avoid the saturation of the optical receiver, adjust the automatic gain control (AGC) parameters of the optical receiver and reduce the gain multiple.

[0125] S334: The OLT sends an adjustment instruction to each related ONU. The instruction includes the adjusted parameter information of the optical transmitter and the sending and receiving strategy parameters that the ONU itself needs to adjust. The performance indicators of the network are continuously monitored for a period of time after the adjustment. If the network performance is improved, the current adjustment strategy is maintained. If the network performance does not improve or deteriorates, the prediction results and adjustment strategy are re-evaluated.

[0126] Specifically, the adjusted parameter information includes transmission power, wavelength, etc. The sending and receiving strategy parameters include sending window start time, AGC parameters, etc. The improvement includes: bit error rate reduction, service transmission success rate improvement, etc.

[0127] Further, the checking of each ONU ranging data, bandwidth utilization and network status, and optimizing configuration according to maintenance suggestions comprises the following steps:

[0128] S41: In the OLT device, the ranging data, bandwidth utilization and network status are collected and stored in the MySQL database of the OLT device. A Web-based visualization interface is constructed through the OLT device to display the ranging data, bandwidth utilization and network status;

[0129] Specifically, the network status includes the packet loss rate, bit error rate, optical signal strength, etc. in the network. These data can be stored by setting monitoring points at the key interfaces of OLT and ONU. For the storage of ranging data, the ONU identifier is used as the index, and each ranging result, timestamp and other information are stored in the corresponding table structure. The bandwidth utilization data is stored in time series, and the upstream and downstream bandwidth usage, bandwidth utilization and other information of each ONU are recorded in different table items at time intervals. The network status data is also stored in time series, and the packet loss rate, bit error rate, optical signal strength, etc. are saved together with the timestamp for subsequent query and analysis.

[0130] The visualization interface uses intuitive charts and graphs to display data. For example, a bar chart is used to show the bandwidth utilization comparison of different ONUs, a line chart is used to show the bandwidth utilization trend of an ONU over a period of time, and a dashboard is used to display key indicators such as the overall packet loss rate and bit error rate of the network.

[0131] S42: A maintenance suggestion generation mechanism based on predefined thresholds and network best practices is set up in the network management system. Maintenance suggestions are displayed in a separate area of ​​the visual interface. Each maintenance suggestion clearly points out the problem, cause, and recommended action, and is sorted according to priority.

[0132] Specifically, for the distance measurement data related rules, if the distance change of a certain ONU exceeds a certain threshold, a maintenance suggestion is generated to prompt the operation and maintenance personnel to check whether the optical fiber connection is loose, whether the equipment is displaced, etc.; for the bandwidth utilization related rules, when the bandwidth utilization of a certain ONU is continuously higher than 90% or lower than 10%, a corresponding maintenance suggestion is generated; for ONUs with high bandwidth utilization, it is recommended to check whether there is abnormal traffic and whether the bandwidth needs to be upgraded; for ONUs with low bandwidth utilization, it is recommended to check whether the service is running normally and whether there are configuration errors, etc.; for the network status related rules, if the packet loss rate is higher than 1% or the bit error rate is higher than 10-6, the operation and maintenance personnel are prompted to check whether the optical link is faulty, whether the equipment is faulty, etc., and it is recommended to perform optical power detection, equipment restart, etc. The priority is to put the most urgent problems in the front, so that the operation and maintenance personnel can pay attention to and deal with them first.

[0133] S43: A configuration operation entry is provided in the visual interface, allowing the operation and maintenance personnel to optimize the configuration of the PON network. The configuration operation entry is restricted by authority management. The operation and maintenance personnel optimize the network configuration according to the maintenance suggestions. After the configuration operation is performed, the network management system records the operation log.

[0134] Specifically, only operation and maintenance personnel with corresponding permissions can perform configuration operations, and the configuration interface is classified according to different configuration items, such as ONU parameter configuration, DBA algorithm parameter adjustment, optical link related parameter adjustment, etc. The operation log includes information such as operation time, operation content, and operator for subsequent auditing and troubleshooting.

[0135] The above implementation modes are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering and technical personnel in the field shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for measuring the distance from an access optical network PON port to an ONU device, characterized in that: The following steps are involved: S1: Configure the ranging control module at the OLT end of the PON network, initiate the ranging signal and collect the returned data, and use the ranging technology to perform the initial static ranging between the ONU and OLT and the dynamic ranging in normal communication; S2: Measure the loop delay of the data signal sent from the OLT downstream to the ONU upstream, adjust the authorization time window in the DBA algorithm according to the measurement results, and dynamically adjust the ONU's sending window according to the ranging data. The delay compensation mechanism adjusts the sending window in real time; S3: Through temperature sensors and device self-checking functions, it monitors environmental changes in real time, intelligently predicts and performs preventive maintenance, and automatically adjusts bandwidth allocation and transmission strategies; S4: Check the ranging data, bandwidth utilization and network status of each ONU, and optimize the configuration according to the maintenance recommendations.

2. The method for measuring the distance from the access optical network PON port to the ONU device according to claim 1, characterized in that: The ranging control module includes: an optical transmitter, an optical receiver, a clock source and a timer, a signal processing unit and a data storage unit; The optical transmitter comprises a driving circuit and a light source using a semiconductor laser; The optical receiver includes a photodetector, a preamplifier, a main amplifier and an equalizer; The clock source and timer include high-precision clock source and timer circuits; The signal processing unit includes a digital signal processor or a field programmable gate array, and an algorithm module.

3. The method for measuring the distance from the access optical network PON port to the ONU device according to claim 1, characterized in that: The distance measurement technology includes: in-band windowing method, out-band method or spread spectrum method; The in-band windowing method includes inserting a specific ranging signal inside the data transmission window and measuring the distance using its return time; The out-of-band method includes transmitting a ranging signal through a frequency band, and performing ranging with a signal in a non-data transmission frequency band; The spread spectrum method includes performing precise ranging using signals generated by spread spectrum technology.

4. The method for measuring the distance from the access optical network PON port to the ONU device according to claim 2, characterized in that: The initialization of static ranging comprises the following steps: When the ONU registers with the OLT, the OLT device is started and the ranging control module is initialized. The signal processing unit generates an initialization ranging authorization message according to the system configuration. The optical transmitter converts this message into an optical signal and sends it to the PON network at the set wavelength and power. After receiving the initial ranging authorization message, the ONU starts to prepare for a response after a random short delay based on its own processing capability and internal delay characteristics. The ONU generates a ranging request message containing its own identification information and converts it into an optical signal and sends it back to the OLT. The optical receiver receives the ranging request optical signal returned by the ONU, and after photoelectric conversion, amplification and equalization processing, transmits the electrical signal to the signal processing unit. The signal processing unit calculates the preliminary distance value based on the time of sending the initialization ranging authorization message and the time of receiving the ranging request message recorded by the clock source and the timer, and stores this distance value and the identification information of the ONU in the data storage unit.

5. The method for measuring the distance from the access optical network PON port to the ONU device according to claim 4, characterized in that: The dynamic ranging in normal communication comprises the following steps: According to a preset time interval or when a specific event is detected, the signal processing unit triggers a dynamic ranging operation, the signal processing unit of the ranging control module generates a precise ranging authorization message according to the current network status and historical information in the database, and the optical transmitter converts the precise ranging authorization message into an optical signal and sends it to the PON network; After receiving the precise ranging authorization message, the ONU adjusts its own transmission timing according to the instructions in the message, and regenerates the ranging request message containing the updated information, and then converts it into an optical signal and sends it back to the OLT. The optical receiver receives the ranging request optical signal returned by the ONU, and after optical-electrical conversion, amplification and equalization processing, transmits the signal to the signal processing unit; The signal processing unit again calculates the updated distance value based on the time information recorded by the clock source and the timer, compares the new distance value with the original data in the basic time delay database, and analyzes the distance change. If the distance change exceeds a certain threshold, the relevant time delay data in the database is updated. At the same time, the signal processing unit passes the new distance information to the unit working with the DBA.

6. The method for measuring the distance from the access optical network PON port to the ONU device according to claim 2, characterized in that: The method measures the loop delay of the data signal sent from the OLT downstream to the ONU upstream, adjusts the authorization time window in the DBA algorithm according to the measurement result, dynamically adjusts the sending window of the ONU according to the ranging data, and the delay compensation mechanism adjusts the sending window in real time; comprising the following steps: S21: When sending a downlink data signal, the ranging control module of the OLT embeds tag information containing a timestamp in the signal. After receiving the downlink data signal with the tag information, the ONU extracts the timestamp and records the time of receiving the signal. S22: When the ONU sends uplink data, it adds the information including the timestamp and the receiving time to the uplink data frame and sends it back to the OLT. The optical receiver of the OLT receives the uplink data frame sent back by the ONU. The signal processing unit in the ranging control module extracts the timestamp and the receiving time from the frame, and records the time when the uplink data frame is received, and calculates the loop delay. S23: The signal processing unit compares and analyzes the calculated loop delay with the historical loop delay data previously stored in the data storage unit, and if there is a change, adjusts the authorization time window in the DBA algorithm; S24: Real-time monitoring of various parameters in the network as feedback information for whether the adjustment of the sending window is effective. By continuously repeating the process of ranging, calculation and adjustment, real-time dynamic adjustment of the ONU sending window is achieved to compensate for the delay changes caused by various factors.

7. The method for measuring the distance from the access optical network PON port to the ONU device according to claim 6, characterized in that: The adjustment of the authorization time window in the DBA algorithm includes: If the loop delay increases and there are a large number of real-time services in the network, the strategy of increasing the authorization time window and reducing the impact on existing services is adopted; If the loop delay increases but the network is mainly used for non-real-time data download services, increase the authorization time window and adjust the proportion of allocated bandwidth at the same time; If the loop delay is reduced, the authorization time window is reduced while not affecting the normal data transmission of the ONU; The increasing of the authorization time window includes adjusting the DBA algorithm based on polling and adjusting the DBA algorithm based on bandwidth prediction.

8. The method for measuring the distance from an access optical network PON port to an ONU device according to claim 1, characterized in that: The method uses temperature sensors and equipment self-checking functions to monitor environmental changes in real time, intelligently predict and perform preventive maintenance, and automatically adjust bandwidth allocation and transmission strategies; the method includes the following steps: S31: Install temperature sensors and humidity sensors in the PON network equipment, regularly check various components of the equipment through the equipment self-check function, record the equipment's operating time, service flow data, and historical fault record data, and pre-process the collected temperature, humidity, equipment operating parameters, and service flow data; S32: Select features related to fault prediction and performance degradation from the preprocessed data, build a decision tree model using the CART algorithm, randomly select preprocessed historical data as a training set, and mark them according to different fault types and performance degradation indicators during the training process so that the model can learn the relationship between data features and faults or performance degradation. Evaluate and optimize the model using the test set. S33: The real-time collected and pre-processed environment and device status data are input into the trained model. The model predicts whether a failure or performance degradation is likely to occur based on the input data. When the model predicts a possible failure or performance degradation, the early warning mechanism is triggered and the bandwidth allocation and transmission strategy are automatically adjusted.

9. The method for measuring the distance from the access optical network PON port to the ONU device according to claim 8, characterized in that: The automatic adjustment of bandwidth allocation and transmission strategy comprises the following steps: S331: When the model predicts a failure or performance degradation, the affected ONUs and the types of services running on the ONUs are analyzed, the impact of the bandwidth requirements of each affected ONU is evaluated, the total available bandwidth resources of the PON network are obtained from the configuration information of the OLT, the bandwidth currently allocated to each ONU is queried in the database, and the remaining available bandwidth is calculated; S332: Allocate additional bandwidth according to the priority of the services on the affected ONUs. For each affected ONU, allocate bandwidth according to the previously evaluated impact of bandwidth demand. If the additional bandwidth demand of the affected ONU exceeds the remaining available bandwidth, adjust the bandwidth of other unaffected ONUs, update the adjusted bandwidth allocation value of each ONU to the relevant parameters of the DBA algorithm, and the dynamic broadband allocation starts to implement a new bandwidth allocation plan according to the updated parameters. S333: Determine the type of transmission problem that occurs according to the prediction result, analyze the impact on the sending and receiving timing strategy of the ONU according to the increase in the processing delay of the signal processing unit, if it is predicted that the signal transmission is affected due to the increase in optical fiber loss, calculate the transmission power that needs to be increased, and the optical transmitter adjusts the transmission power according to the calculated transmission power value; if it is predicted that the internal processing delay of the ONU increases or the timing relationship in the network changes, adjust the sending window of the ONU; if it is predicted that the characteristics of the optical signal change, adjust the relevant parameters of the optical receiver of the ONU; if the transmission wavelength changes, adjust the filter center wavelength of the optical receiver; S334: The OLT sends an adjustment instruction to each related ONU. The instruction includes the adjusted parameter information of the optical transmitter and the sending and receiving strategy parameters that the ONU itself needs to adjust. The performance indicators of the network are continuously monitored for a period of time after the adjustment. If the network performance is improved, the current adjustment strategy is maintained; if the network performance does not improve or deteriorates, the prediction results and adjustment strategy are re-evaluated.

10. The method for measuring the distance from an access optical network PON port to an ONU device according to claim 1, characterized in that: The method of checking the ranging data, bandwidth utilization and network status of each ONU and optimizing the configuration according to the maintenance suggestions comprises the following steps: S41: In the OLT device, the ranging data, bandwidth utilization and network status are collected and stored in the MySQL database of the OLT device. A Web-based visualization interface is constructed through the OLT device to display the ranging data, bandwidth utilization and network status; S42: A maintenance suggestion generation mechanism based on predefined thresholds and network best practices is set up in the network management system. Maintenance suggestions are displayed in a separate area of ​​the visual interface. Each maintenance suggestion clearly points out the problem, cause, and recommended action, and is sorted according to priority. S43: A configuration operation entry is provided in the visual interface, allowing the operation and maintenance personnel to optimize the configuration of the PON network. The configuration operation entry is restricted by authority management. The operation and maintenance personnel optimize the network configuration according to the maintenance suggestions. After the configuration operation is performed, the network management system records the operation log.

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