Distributed photovoltaic direct acquisition and direct control cross-layer cooperative communication method and system

Abstract

This invention belongs to the field of distributed photovoltaic communication technology, and provides a method and system for cross-layer collaborative communication of distributed photovoltaic direct acquisition and control. The technical solution involves generating and distributing network parameters; multiple inverter terminals and data forwarding devices performing bidirectional authentication with the edge gateway, and negotiating session keys after successful authentication; periodically sampling channel indicators and calculating channel quality scores based on the sampled indicators; determining whether a link has failed based on set conditions; if it has failed, triggering link self-healing and path reconstruction processes; if it has not failed, further determining whether frequency switching triggering conditions are met based on the channel quality score; if met, triggering a dynamic channel switching process; determining whether the channel switching was successful; if the switching failed, reverting to a backup channel according to rollback conditions, and simultaneously triggering the link self-healing process; if the switching was successful, updating the dwell time. It ensures control command reachability and closed-loop stability even when interference, congestion, and faults coexist.

Description

Technical Field

[0001] This invention belongs to the field of distributed photovoltaic communication technology, and particularly relates to a method and system for cross-layer collaborative communication for direct acquisition and control of distributed photovoltaic systems. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Low-voltage distributed photovoltaic energy storage and charging terminals exhibit typical characteristics of "large scale, scattered locations, and complex deployment environments." The grid-side management of these massive terminals is gradually upgrading from a communication mode primarily based on data monitoring to a closed-loop control mode with "direct acquisition and direct control" capable of second-level or even millisecond-level response. This shift places stringent requirements on the anti-interference capabilities, deterministic low latency, and inherent security of wireless communication links.

[0004] Existing general IoT networking solutions typically include basic processes such as terminal authentication, session key negotiation, and channel state monitoring and optimization, which can alleviate unauthorized access and channel degradation to some extent. However, in the specific scenario of distributed photovoltaic direct acquisition and control, existing solutions focus more on channel optimization itself, but lack effective backup and rapid self-healing mechanisms if channel switching fails, failing to guarantee the continuous availability of the command channel within the second-level control closed-loop window. Secondly, there is a lack of deterministic latency guarantee mechanisms for grid-side control / protection services, making it difficult to ensure the priority arrival of control frames during group control or congestion. Thirdly, security mechanisms are incompatible with low-power terminals; encryption and integrity are mostly general terminal access security descriptions, without constraining the implementation path of low-power terminals on the air interface side. In addition, there is a lack of coordination mechanisms, with most being general channel optimization strategies that fail to fully utilize the coordination mechanisms of distributed photovoltaic systems such as "co-cluster interference, sparse / dynamic topology, and centralized scheduling by edge gateways." Therefore, these solutions cannot meet the communication requirements of distributed photovoltaic direct acquisition and control. Summary of the Invention

[0005] To address at least one of the technical problems mentioned above, this invention provides a method and system for cross-layer collaborative communication of distributed photovoltaic direct acquisition and control, which ensures the reachability of control commands and the stability of the closed loop even when interference, congestion, and faults coexist.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of the present invention provides a method for cross-layer collaborative communication of direct photovoltaic power generation and control, comprising the following steps: Network setup and security initialization: Generate and distribute network parameters, and multiple inverter terminals and data forwarding devices perform two-way authentication with the edge gateway, and negotiate session keys after successful authentication; Perform channel quality monitoring and scoring: periodically sample channel indicators and calculate channel quality scores based on the sampled channel indicators; Link self-healing and reconstruction: When a communication link fails, the link self-healing and path reconstruction process is triggered; Adaptive channel switching: If the communication link is not lost, the frequency switching trigger condition is met based on the channel quality score and the set conditions. If the conditions are met, a dynamic channel switching trigger command is triggered; otherwise, the current channel is maintained and monitoring continues. Enhanced communication reliability: Determine whether the channel switch was successful. If the switch fails, roll back to the backup channel according to the rollback conditions and trigger the link self-healing process. If the switch is successful, update the dwell time.

[0007] Furthermore, the network parameters generated and distributed by the edge gateway include at least the cluster ID, the set of available channels, the backup channel, the service category and priority mapping, and threshold parameters for channel quality assessment and link status determination.

[0008] Furthermore, the formula for calculating the channel quality score Q is: Where w1, w2, w3, and w4 are the weights corresponding to each channel indicator, RSSI represents signal strength indicator, SNR represents signal-to-noise ratio, PER represents packet error rate or packet loss rate, BusyRatio represents the channel busy-to-idle ratio, and w1+w2+w3+w4=1; Norm(·) is a normalization function used to map the original indicators of different dimensions to the interval [0,1].

[0009] Furthermore, when a communication link fails, a link self-healing and path reconstruction process is triggered, which specifically includes: Fault detection and type determination are performed. If the fault type is congestion or collision, the upper limit of retransmission times, retransmission interval and backoff parameters are dynamically adjusted according to the service level to ensure the retransmission resources of control frames. If the channel degradation is caused by regional interference, and retransmission or backoff still cannot meet the threshold, the link budget parameters are adjusted according to the preset level, and the channel quality score Q is resampled and calculated. If the channel quality score Q is still lower than the threshold, a synchronous frequency switching is requested. If a node or access point fails, or a route is broken, a route switch without a frequency change will be performed. If the problem still cannot be resolved, a local multi-hop reconstruction and a routing table reconstruction will be performed.

[0010] Furthermore, the criteria for determining whether the frequency switching trigger condition is met are as follows: when the channel quality score Q is lower than the trigger threshold Q_th and the set period T_hold is maintained, and the minimum dwell time T_min is met, a dynamic channel switching trigger command is issued.

[0011] Furthermore, if the frequency switching triggering conditions are met, the dynamic channel handover process is triggered, including: Select the target channel and broadcast a channel handover announcement frame. Calculate the quality score and handover cost of each channel in the available channel set, and select the channel with the highest comprehensive score as the target channel. After receiving the announcement frame, the terminal within the cluster switches to the target channel at the effective time t_eff and sends back an ACK confirmation to the data forwarding device. The data forwarding device then performs ACK aggregation and reports to the edge gateway. This includes prioritizing service flows in the terminal and the data forwarding device, configuring a preemptive scheduling strategy for high-priority services, and suppressing ACK aggregation for broadcast or group control commands.

[0012] Furthermore, the method also includes the edge gateway aggregating real-time data and link status data from the entire network, generating a cluster-level interference profile, and performing closed-loop optimization.

[0013] A second aspect of the present invention provides a distributed photovoltaic direct acquisition and control cross-layer collaborative communication system, including an edge gateway, at least one data forwarding device, and multiple inverter terminals; The edge gateway is used to generate and distribute network parameters; Multiple inverter terminals and data forwarding devices perform two-way authentication with the edge gateway, and negotiate session keys after successful authentication; The inverter terminal and data forwarding device periodically sample channel indicators and calculate the channel quality score based on the sampled channel indicators; The inverter terminal and / or data forwarding device are configured as follows: When a communication link fails, the link self-healing and path reconstruction process is triggered. If the communication link is not lost, the frequency switching trigger condition is met based on the channel quality score and the set conditions. If the conditions are met, a dynamic channel switching trigger command is triggered; otherwise, the current channel is maintained and monitoring continues. Determine whether the channel switch was successful. If the switch failed, roll back to the backup channel according to the rollback conditions and trigger the link self-healing process. If the switch was successful, update the dwell time.

[0014] Furthermore, when a link fails, a link self-healing and path reconstruction process is triggered, which specifically includes: Fault detection and type determination are performed. If the fault type is congestion or collision, the upper limit of retransmission times, retransmission interval and backoff parameters are dynamically adjusted according to the service level to ensure the retransmission resources of control frames. If the channel degradation is caused by regional interference, and retransmission or backoff still cannot meet the threshold, the link budget parameters are adjusted according to the preset level, and the channel quality score Q is resampled and calculated. If the channel quality score Q is still lower than the threshold, a synchronous frequency switching is requested. If a node / access point fails or a route is broken, a route switch without a frequency change will be performed. If the problem still cannot be resolved, a local multi-hop reconstruction and a routing table reconstruction will be performed.

[0015] Furthermore, if the frequency switching triggering conditions are met, the dynamic channel handover process is triggered, including: Select the target channel and broadcast a channel handover announcement frame. Calculate the quality score and handover cost of each channel in the available channel set, and select the channel with the highest comprehensive score as the target channel. After receiving the announcement frame, the terminal within the cluster switches to the target channel at the effective time t_eff and sends back an ACK confirmation to the data forwarding device. The data forwarding device then performs ACK aggregation and reports to the edge gateway. This includes prioritizing service flows in the terminal and the data forwarding device, configuring a preemptive scheduling strategy for high-priority services, and suppressing ACK aggregation for broadcast or group control commands.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention innovatively proposes a cross-layer collaborative communication method for direct acquisition and control of distributed photovoltaic systems, and develops a cross-layer collaborative communication system for direct acquisition and control of distributed photovoltaic systems. It unifies channel quality monitoring, synchronous frequency switching, link self-healing / access point switching, and coordinates the distribution of cluster-level interference and policy parameters by the edge gateway. This ensures the reachability of control commands and closed-loop stability even when interference, congestion, and faults coexist, enhances the reliability of distributed photovoltaic communication channels, and solves the problem that traditional communication methods cannot guarantee the stable execution of critical control services when interference, congestion, link interruption, and attack risks coexist.

[0017] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 This is a flowchart of the distributed photovoltaic direct acquisition and control cross-layer collaborative communication method provided in the embodiments of the present invention. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] Example 1 like Figure 1 As shown, this embodiment provides a cross-layer collaborative communication method for direct acquisition and control of distributed photovoltaic power. Solid arrows indicate the execution order of the method steps; dashed lines without arrows indicate the input dependency or cross-application relationship between modules and steps; dashed lines with arrows indicate the direction of information interaction (e.g., statistical reporting and parameter distribution). Figure 1 The circular connector in the diagram represents the merging point of the process loop, used to merge multiple return paths into the monitoring loop entry point. The method specifically includes the following steps: Step 1: Networking and Security Initialization: The edge gateway generates and distributes network parameters, and multiple inverter terminals and data forwarding devices perform two-way authentication with the edge gateway, and negotiate session keys after successful authentication; In this embodiment, the network parameters generated and distributed by the edge gateway include at least the cluster ID and the set of available channels. , backup channel Service category and priority mapping, as well as threshold parameters used for channel quality assessment and link status determination, including Q_th, T_hold, etc.

[0024] When multiple inverter terminals and data forwarding devices perform two-way authentication with the edge gateway, the devices and gateways use SM2 certificate chain-based mutual authentication. After successful authentication, session keys K_s are negotiated and established for different service domains, and a key rolling update strategy is set. Key contexts are established for different service domains (control / alarm / telemetry), and validity periods and rolling windows are set. Lightweight updates are performed when the key is about to expire or a risk is triggered (without affecting business continuity).

[0025] Step 2: Perform channel quality monitoring and scoring: The inverter terminal and data forwarding device periodically sample channel indicators and calculate the channel quality score Q based on the sampled channel indicators. This includes the following steps: Step 201: The inverter terminal and data forwarding device periodically sample channel indicators; In this embodiment, the sampling metrics specifically include Signal Strength Indicator (RSSI), Signal-to-Noise Ratio (SNR), Packet Error Rate (PER), BusyRatio, Round-Trip Time (RTT), etc.

[0026] Step 202: Calculate the channel quality score Q based on the sampled channel indicators; In this embodiment, when calculating the channel quality score Q, a sliding window statistical index is used, and a minimum dwell time T_min and a hysteresis interval ΔQ are set to avoid frequent handover. The formula for calculating the channel quality score Q in this embodiment is: Where w1, w2, w3, and w4 are the weights corresponding to each channel indicator, and RSSI, SNR, PER, and BusyRatio are the signal strength indicator, signal-to-noise ratio, packet error rate or packet loss rate, and channel busy-idle ratio, respectively, with Σwi=1; Norm(·) is a normalization function used to map indicators such as RSSI, SNR, and PER to the [0,1] interval to eliminate dimensional differences and facilitate weighted summation. For indicators where "the larger the value, the better" (RSSI, SNR), Norm(x)=clip((x x_min) / (x_max x_min),0,1); For the PER (Percentage Error Rate) indicator, which is considered to be "the smaller the value, the better", it can be normalized as described above and then set to 1 in the score. Norm(PER); BusyRatio itself is located in the [0,1] interval and can be used directly; where x_min and x_max can be determined by the device calibration value or historical statistical quantiles.

[0027] The above formula is only an example calculation and can be adjusted according to the selected indicators.

[0028] Step 3: Determine whether the communication link has failed based on the set conditions. If it has failed, trigger the link self-healing and path reconstruction process. Otherwise, further determine whether the frequency switching triggering condition is met based on the channel quality score. If it is met, trigger the dynamic channel switching triggering command and determine whether the channel switching is successful. If the switching fails, return to the backup channel according to the rollback conditions and trigger the link self-healing process at the same time. Specifically, the steps include the following: Step 301: Determine whether the link is faulty based on the set conditions; In this embodiment, if K consecutive heartbeats are lost or M consecutive control frame ACK times out, the link is determined to be faulty. Step 302: When a link fails, trigger the link self-healing and path reconstruction process; Existing network self-healing technologies can perform route recalculation or routing table reconstruction after detecting link failures to restore network connectivity and improve network recovery capabilities. However, they typically focus on "connectivity restoration" and lack cross-layer coupling designs for distributed photovoltaic direct acquisition and control scenarios. On the one hand, they do not link wireless channel degradation / regional interference with self-healing triggering conditions and channel switching mechanisms, which can easily lead to frequent reconstruction or delayed recovery. On the other hand, they lack recovery strategies that combine service priority and control closed-loop delay constraints, making it difficult to guarantee the priority arrival of control / protection commands and deterministic queuing delays during the recovery process.

[0029] In the event of link failure or frequency switching failure, this application employs a closed-loop mechanism of "layered rapid self-healing + backup rollback": First, adaptive retransmission and backoff are performed at the MAC layer according to service level, and control frames are restored within a time limit; if the threshold is still not met, physical layer parameters are further adjusted and the channel quality score Q is reassessed; when the access point is determined to be faulty or the route is broken, access point handover without frequency switching and local multi-hop reconstruction are performed; when the regional interference is determined to be localized, synchronous frequency switching is coordinated and backup channel rollback is provided. Thus, even when interference, congestion, and faults coexist, the command channel can still be restored preferentially within a second-level control window.

[0030] Step 3021, Fault Detection and Type Determination: If K consecutive heartbeats are lost or M consecutive control frame ACK times out, the link is determined to be faulty; at the same time, based on the change characteristics of RSSI, SNR, PER, BusyRatio, and RTT within the sampling window, the fault type is classified into at least congestion / collision, regional interference (channel degradation), or node / access point failure, and the fault type is recorded for subsequent self-healing decision-making.

[0031] Step 3022, Adaptive retransmission and backoff: Dynamically adjust the upper limit of retransmission times, retransmission interval and backoff parameters according to service level and fault type, and give priority to ensuring retransmission resources for control frames (Class-0); For example, a higher maximum retransmission count and a smaller initial backoff window are set for Class-0, and the backoff window / transmission rate is adaptively adjusted according to BusyRatio to reduce collisions in congested scenarios and recover quickly in scenarios with minor packet loss.

[0032] Step 3023, Adaptive Physical Layer Parameters and Reassessment: If retransmission / backoff still cannot meet the threshold, adjust the link budget parameters such as transmit power, coding rate / error correction redundancy (FEC), and modulation scheme according to the preset level, and resample and calculate the channel quality score Q and RTT; if Q recovers to Q_th+ΔQ and RTT meets the threshold, then end the self-healing and return to monitoring; otherwise, proceed to step 3024 or trigger the frequency switching process.

[0033] Step 3024, Access Point Switching (Route Switching, Frequency Switching): When the fault type is determined to be node / access point failure or route breakage, or when the re-evaluation in Step 3023 still does not meet the threshold, the neighbor quality table is maintained without changing the current channel. The parent node / relay or neighboring data forwarding device with the highest score is selected as the new access point, and the local forwarding relationship is updated to restore the control and data channels.

[0034] When the access point switching fails or there is no available access point in the neighbor table in step 3024, local route discovery / reconstruction is initiated only in the affected area, multi-hop paths are established and the local routing table is updated, and the reconstruction range and frequency are limited to avoid reconstruction of the entire network. After reconstruction is completed, Q and RTT are sampled again and calculated. If the threshold is met, the self-healing ends and the monitoring is returned. Otherwise, the edge gateway is reported and frequency switching or alarm is triggered according to the policy.

[0035] In one implementation, steps 3021 to 3025 are executed in a coordinated manner according to the strategy of "lightweight priority, step-by-step escalation, and time-limited exit": First, fault detection and classification are completed in step 3021; ​​if the fault type is congestion / collision, step 3022 is executed first to quickly recover through retransmission and backoff parameter adjustment; if the channel degradation is caused by regional interference, step 3023 is executed to increase the link budget and re-evaluate Q. If the re-evaluation is still below the threshold, a request can be made to the edge gateway / data forwarding device to trigger the synchronous frequency switching in step 303; if the node / access point fails or the route is broken, step 3024 is entered to perform route switching without frequency switching; if recovery is still not possible, local multi-hop reconstruction is performed. Each action can be set with a maximum number of attempts or a maximum time T_rec. If these are exceeded, rollback / alarm is initiated to ensure the time determinism of the control loop.

[0036] Step 303: If the link is not failed, further determine whether the frequency switching trigger condition is met based on the channel quality score and the set conditions. If it is met, trigger the dynamic channel switching trigger command; otherwise, maintain the current channel and continue monitoring. In this embodiment, the criteria for determining whether the frequency switching trigger condition is met are as follows: when Q is lower than the trigger threshold Q_th and continues for a set period T_hold, and the minimum dwell time T_min is met, a dynamic channel switching trigger command is issued. When Q recovers to Q_th+ΔQ and continues for T_relax periods, the intervention state can be exited.

[0037] When the frequency switching condition is triggered, the edge gateway or data forwarding device initiates a synchronous handover process to ensure that terminals within the cluster complete the handover at a consistent effective time, avoiding disconnection caused by "half-network handover". The synchronous handover process initiated by the edge gateway or data forwarding device when the frequency switching condition is triggered specifically includes: Step 3031: Select the target channel and broadcast a channel switching announcement frame; In this embodiment, when selecting the target channel, the quality score and handover cost of each channel in the available channel set are calculated, and the channel with the highest comprehensive score is selected as the target channel. Specifically, for candidate channels ci∈C, calculate the comprehensive score Q(ci) and the handover cost Cost(ci), and select the channel with the largest Score(ci) = Q(ci) - λ·Cost(ci) as the target channel c. ; where λ is the cost weighting coefficient, used to balance channel quality improvement and handover cost. The larger λ is, the more inclined to reduce handover frequency and avoid jitter handover. It can be adaptively configured by the edge gateway in combination with the service closed-loop latency sensitivity, historical handover success rate and neighboring cluster interference. Cost can include the number of historical failures, the expected handover time, and the risk of conflict with neighboring clusters.

[0038] Furthermore, the channel handover announcement frame at least includes {cluster ID, target channel c}. Effective time t_eff, announcement number SN, rollback conditions, verification / MAC}.

[0039] Step 3032: After receiving the announcement frame, the terminal within the cluster switches to the target channel c at the effective time t_eff. It also sends back an acknowledgment (ACK), and the data forwarding device aggregates the ACKs. To meet the "second-level closed-loop control" requirement of distributed photovoltaic systems, service hierarchy and preemptive QoS scheduling are implemented in the inverter terminal and data forwarding device: service flows are prioritized according to control / protection commands, alarm / critical operating data, and ordinary telemetry / logs, and preemptive scheduling strategies are configured for high-priority services to ensure deterministic queuing delay for control / protection commands; at the same time, in broadcast scenarios such as group control or synchronous frequency switching (channel switching announcement frame CSA), the data forwarding device aggregates / suppresses ACKs, summarizing multiple terminal ACKs into an aggregated ACK and reporting it to the edge gateway to suppress ACK storms, reduce collisions, and ensure that handover confirmation and critical control service transmission are completed within the confirmation window T_ack.

[0040] Specifically, the steps include the following: Step 30321, Service Classification: At least classify into Class-0 control / protection instructions, Class-1 alarms / critical operational data, and Class-2 ordinary telemetry / logs; configure the maximum tolerable queuing delay D_max and the expiration discard policy for each class.

[0041] Step 30322, Preemptive Scheduling: A preemptive priority queue is adopted; when Class-0 arrives, the transmission of Class-1 / 2 can be interrupted; and time slices / token buckets are used to guarantee low priority and avoid long-term starvation.

[0042] Step 30323, Broadcast / Group Control ACK Suppression: The data forwarding device performs local retransmission and ACK aggregation on the broadcast control frame: The terminal uses group / random backoff ACK, and the forwarding device summarizes them into aggregated ACKs and reports them to the gateway.

[0043] Step 30324, Degradation strategy under congestion: When BusyRatio or queue occupancy exceeds the threshold, automatically reduce the reporting frequency of Class-2 or transfer it to the cache, and directly discard data that exceeds the freshness window to release air interface resources and prioritize Class-0 / 1 services.

[0044] Note: Steps 30321 and 30322 are the basic scheduling procedures on the transmitting side and are executed for each packet to be transmitted; Step 30323 is triggered when the packet to be transmitted is a broadcast / group control packet (including Channel Switching Announcement Frame CSA and group control instructions) and requires terminal confirmation, and is used to complete the confirmation within the T_ack window and suppress the ACK storm; Step 30324 is triggered when the channel busy-idle ratio or queue occupancy exceeds the threshold, and degrades or limits low-priority services to release resources, and is not limited to the ACK aggregation process.

[0045] Step 303: Determine whether the channel switch was successful. If the switch fails, roll back to the backup channel according to the rollback conditions and trigger the link self-healing process. If the switch is successful, update the dwell time. In this embodiment, the judgment condition is set as follows: if the proportion of acknowledgments received within window T_ack is ≥ θ and the round-trip delay of the control frame meets the threshold, then the handover is determined to be successful. If the set conditions are not met, the switchover fails and the link self-healing process is triggered. The terminal or data forwarding device performs self-healing according to the hierarchical strategy of "lowest cost and fastest recovery". The specific link self-healing process is the same as the process in step 302, and will not be repeated here.

[0046] Existing wireless systems typically perform integrity checks and decryption on signaling before and after security mode switching to avoid out-of-order errors. However, these are mostly general security signaling mechanisms within the protocol stack and are not optimized for the constraints of distributed photovoltaic low-power terminals under second-level control loops. For example, bidirectional authentication has high overhead, packet encryption and integrity protection are not coordinated with frequency switching / self-healing processes, and there is a lack of lightweight implementations for replay protection and key rolling updates. Based on the bidirectional authentication and session key K_s establishment in step 301, this application performs lightweight packet encryption and integrity protection on control / alarm / telemetry packets on the SUB-G air interface side, and introduces sequence number SN / timestamp TS and sliding window verification in the control signaling to achieve replay protection. At the same time, it sets key validity periods and rolling windows according to service domains and adopts a key update process with minimal interaction to avoid additional interactions and latency jitter in frequency switching or congestion scenarios, thereby achieving security assurance in coordination with reliability enhancement mechanisms under low power constraints.

[0047] Step 4: Based on the established session key, perform air interface security processing: encrypt and protect the integrity of communication data packets, and use sequence number or timestamp mechanism to defend against replay attacks; Specifically, the steps include the following: Step 401, Packet Encryption: Use SM4 symmetric encryption (CTR / CCM and other modes are optional) for uplink / downlink packets. Step 402, Integrity Protection: Calculate MAC for groups; SM2 signature can be selected for critical control frames to improve non-repudiation; Step 403, Anti-replay: Introduce sequence number (SN) / timestamp (TS) and sliding window verification in the control frame; discard SNs outside the window or duplicate SNs; Step 404, Key Rolling Update: Key updates are performed based on business domain or risk triggers; this is completed through minimal handshake to avoid congestion caused by simultaneous key changes at the same terminal.

[0048] Step 405, Hardware Acceleration (Optional): The SUB-G communication module integrates the SM4 hardware engine to reduce CPU usage and power consumption.

[0049] Explanation: Steps 401 to 403 are mandatory processing steps for each transmit and receive packet—the sending side first completes encryption and calculates the MAC, while simultaneously carrying the sequence number SN / timestamp TS in the control packet; the receiving side first verifies the MAC and SN / TS (anti-replay) before decryption; step 404 is a periodic or risk-triggered key rolling update process; step 405 is a hardware acceleration option for implementing the encryption and decryption operations in step 401. The air interface security processing permeates the entire process of channel monitoring, frequency switching, self-healing, and QoS scheduling, especially in dynamic channel switching, to protect the Channel Switching Announcement Frame (CSA), Switching Confirmation ACK, and rollback instructions: before sending the CSA, its integrity is protected and the SN / TS is carried; the terminal performs verification before executing the switch to avoid forged or replayed switch instructions; ACK aggregation reporting is also protected to prevent malicious injection of ACKs leading to misjudgments of the switch.

[0050] Step 5: The edge gateway aggregates real-time data and link status data from the entire network, generates a cluster-level interference profile, and performs closed-loop optimization; Specifically, the steps include the following: Step 501, Status Aggregation: Summarize the Q, PER, RTT, self-healing logs and queue congestion indicators reported by each terminal / forwarding device to form cluster-level interference heat and reliability statistics; Step 502, Parameter Adaptation: Send updated parameters (channel set, Q_th, T_hold, K / M threshold, backoff parameters, FEC level, etc.) to high interference clusters.

[0051] Step 503, Control Strategy Assurance: Issue control commands such as energy scheduling, anti-backflow, and power limiting according to service priority; when the link degrades, prioritize the protection of the control command channel and reduce the frequency of low priority reports.

[0052] Step 504, Global Coordination (Optional): De-collision allocation of adjacent cluster channel sets; switch in batches if necessary to avoid system jitter.

[0053] Example 2 This embodiment provides a distributed photovoltaic direct acquisition and control cross-layer collaborative communication system, including an edge gateway, at least one data forwarding device, and multiple inverter terminals; The edge gateway is used to generate and distribute network parameters; Multiple inverter terminals and data forwarding devices perform two-way authentication with the edge gateway, and negotiate session keys after successful authentication; The inverter terminal and data forwarding device periodically sample channel indicators and calculate the channel quality score based on the sampled channel indicators; The inverter terminal and / or data forwarding device are configured as follows: When a communication link fails, the link self-healing and path reconstruction process is triggered. If the communication link is not lost, the frequency switching trigger condition is met based on the channel quality score and the set conditions. If the conditions are met, a dynamic channel switching trigger command is triggered; otherwise, the current channel is maintained and monitoring continues. Determine whether the channel switch was successful. If the switch failed, roll back to the backup channel according to the rollback conditions and trigger the link self-healing process. If the switch was successful, update the dwell time.

[0054] As a further implementation, the network parameters generated and distributed by the edge gateway include at least the cluster ID, the set of available channels, the backup channel, the service category and priority mapping, and the threshold parameters used for channel quality assessment and link status determination.

[0055] As a further implementation method, the formula for calculating the channel quality score Q is:

[0056] Where w1, w2, w3, and w4 are the weights corresponding to each channel indicator, RSSI represents signal strength indicator, SNR represents signal-to-noise ratio, PER represents packet error rate or packet loss rate, BusyRatio represents the channel busy-to-idle ratio, and w1+w2+w3+w4=1, Norm(·) represents the normalization function, which is used to map the channel indicators to the interval [0,1].

[0057] As a further implementation, when a link fails, a link self-healing and path reconstruction process is triggered, specifically including: Perform fault detection and type determination. If the fault type is congestion / collision, dynamically adjust the upper limit of retransmission times, retransmission interval and backoff parameters according to the service level to ensure the retransmission resources of control frames. If the channel degradation is caused by regional interference, and retransmission / backoff still cannot meet the threshold, the link budget parameters are adjusted according to the preset level, and the channel quality score Q is resampled and calculated. If the channel quality score Q is still lower than the threshold, a synchronous frequency switching is requested. If the failure is due to node / access point failure or route breakage, the route is switched without frequency switching. If it still cannot be restored, local multi-hop reconstruction and routing table reconstruction are performed.

[0058] As a further implementation method, the basis for determining whether the frequency switching trigger condition is met is: when the channel quality score Q is lower than the trigger threshold Q_th and the set period T_hold is continuously met, and the minimum dwell time T_min is satisfied, a dynamic channel switching trigger command is issued.

[0059] As a further implementation, if the frequency switching triggering condition is met, a dynamic channel handover process is triggered, including: Select the target channel and broadcast a channel handover announcement frame. Calculate the quality score and handover cost of each channel in the available channel set, and select the channel with the highest comprehensive score as the target channel. After receiving the announcement frame, the terminal within the cluster switches to the target channel at the effective time t_eff and sends back an ACK confirmation to the data forwarding device. The data forwarding device then performs ACK aggregation and reports to the edge gateway. This includes prioritizing service flows in the terminal and the data forwarding device, configuring a preemptive scheduling strategy for high-priority services, and suppressing ACK aggregation for broadcast or group control commands.

[0060] As a further implementation, the method also includes an edge gateway aggregating real-time data and link status data from the entire network, generating a cluster-level interference profile, and performing closed-loop optimization.

[0061] It should be noted that the specific implementation of the distributed photovoltaic direct acquisition and control cross-layer collaborative communication system in this embodiment of the invention is similar to the specific implementation of the distributed photovoltaic direct acquisition and control cross-layer collaborative communication method in this embodiment of the invention. Please refer to the description in the method section for details. In order to reduce redundancy, it will not be repeated here.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for cross-layer collaborative communication in direct-source and direct-control of distributed photovoltaic power, characterized in that, include: Network setup and security initialization: Generate and distribute network parameters, and multiple inverter terminals and data forwarding devices perform two-way authentication with the edge gateway, and negotiate session keys after successful authentication; Perform channel quality monitoring and scoring: periodically sample channel indicators and calculate channel quality scores based on the sampled channel indicators; Link self-healing and reconstruction: When a communication link fails, the link self-healing and path reconstruction process is triggered; Adaptive channel switching: If the communication link is not lost, the frequency switching trigger condition is met based on the channel quality score and the set conditions. If the conditions are met, a dynamic channel switching trigger command is triggered; otherwise, the current channel is maintained and monitoring continues. Enhanced communication reliability: Determine whether the channel switch was successful. If the switch fails, return to the backup channel according to the rollback conditions and trigger the link self-healing process. If the switch is successful, update the dwell time.

2. The distributed photovoltaic direct acquisition and control cross-layer collaborative communication method as described in claim 1, characterized in that, The generated and distributed network parameters include at least the cluster ID, the set of available channels, the backup channel, the service category and priority mapping, and threshold parameters for channel quality assessment and link status determination.

3. The distributed photovoltaic direct acquisition and control cross-layer collaborative communication method as described in claim 1, characterized in that, The formula for calculating the channel quality score Q is: Where w1, w2, w3, and w4 are the weights corresponding to each channel indicator, RSSI represents signal strength indicator, SNR represents signal-to-noise ratio, PER represents packet error rate or packet loss rate, BusyRatio represents the channel busy-to-idle ratio, and w1+w2+w3+w4=1, Norm(·) represents the normalization function, which is used to map the channel indicators to the interval [0,1].

4. The distributed photovoltaic direct acquisition and control cross-layer collaborative communication method as described in claim 1, characterized in that, When a communication link fails, a link self-healing and path reconstruction process is triggered, which includes: Fault detection and type determination are performed. If the fault type is congestion or collision, the upper limit of retransmission times, retransmission interval and backoff parameters are dynamically adjusted according to the service level to ensure the retransmission resources of control frames. If the channel degradation is caused by regional interference, and retransmission or backoff still cannot meet the threshold, the link budget parameters are adjusted according to the preset level, and the channel quality score Q is resampled and calculated. If the channel quality score Q is still lower than the threshold, a synchronous frequency switching is requested. If a node or access point fails, or a route is broken, a route switch without a frequency change will be performed. If the problem still cannot be resolved, a local multi-hop reconstruction and a routing table reconstruction will be performed.

5. The distributed photovoltaic direct acquisition and control cross-layer collaborative communication method as described in claim 1, characterized in that, The criteria for determining whether the frequency switching trigger condition is met are as follows: when the channel quality score Q is lower than the trigger threshold Q_th and the set period T_hold is maintained, and the minimum dwell time T_min is met, a dynamic channel switching trigger command is issued.

6. The distributed photovoltaic direct acquisition and control cross-layer collaborative communication method as described in claim 1, characterized in that, If the frequency switching triggering conditions are met, the dynamic channel handover process is triggered, including: Select the target channel and broadcast a channel handover announcement frame. Calculate the quality score and handover cost of each channel in the available channel set, and select the channel with the highest comprehensive score as the target channel. After receiving the announcement frame, the terminal within the cluster switches to the target channel at the effective time t_eff and sends back an ACK confirmation to the data forwarding device. The data forwarding device then performs ACK aggregation and reports to the edge gateway. This includes prioritizing service flows in the terminal and the data forwarding device, configuring a preemptive scheduling strategy for high-priority services, and suppressing ACK aggregation for broadcast or group control commands.

7. The distributed photovoltaic direct acquisition and control cross-layer collaborative communication method as described in claim 1, characterized in that, The method also includes edge gateways aggregating real-time data and link status data from the entire network, generating cluster-level interference profiles, and performing closed-loop optimization.

8. A distributed photovoltaic direct-source and direct-control cross-layer collaborative communication system, characterized in that, It includes an edge gateway, at least one data forwarding device, and multiple inverter terminals; The edge gateway is used to generate and distribute network parameters; Multiple inverter terminals and data forwarding devices perform two-way authentication with the edge gateway, and negotiate session keys after successful authentication; The inverter terminal and data forwarding device periodically sample channel indicators and calculate the channel quality score based on the sampled channel indicators; The inverter terminal and / or data forwarding device are configured as follows: When a communication link fails, the link self-healing and path reconstruction process is triggered. If the communication link is not lost, the frequency switching trigger condition is met based on the channel quality score and the set conditions. If the conditions are met, a dynamic channel switching trigger command is triggered; otherwise, the current channel is maintained and monitoring continues. Determine whether the channel switch was successful. If the switch fails, roll back to the backup channel according to the rollback conditions and trigger the link self-healing process. If the switch is successful, update the dwell time.

9. The distributed photovoltaic direct-source and direct-control cross-layer collaborative communication system as described in claim 8, characterized in that, When a link fails, the link self-healing and path reconstruction process is triggered, which includes: Fault detection and type determination are performed. If the fault type is congestion or collision, the upper limit of retransmission times, retransmission interval and backoff parameters are dynamically adjusted according to the service level to ensure the retransmission resources of control frames. If the channel degradation is caused by regional interference, and retransmission or backoff still cannot meet the threshold, the link budget parameters are adjusted according to the preset level, and the channel quality score Q is resampled and calculated. If the channel quality score Q is still lower than the threshold, a synchronous frequency switching is requested. If a node / access point fails or a route is broken, a route switch without a frequency change will be performed. If the problem still cannot be resolved, a local multi-hop reconstruction and a routing table reconstruction will be performed.

10. The distributed photovoltaic direct-source and direct-control cross-layer collaborative communication system as described in claim 8, characterized in that, When the frequency switching triggering condition is met, the edge gateway and / or data forwarding device triggers a dynamic channel switching process, including: selecting a target channel and broadcasting a channel switching announcement frame; calculating the quality score and switching cost of each channel in the available channel set; selecting the channel with the highest comprehensive score as the target channel; after receiving the announcement frame, the terminal in the cluster switches to the target channel at the effective time t_eff and sends back an ACK; the data forwarding device performs ACK aggregation on the ACK and reports it to the edge gateway.

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