Deterministic collaborative data transmission method for deep integration of public and private networks

Abstract

The invention provides a public and private network deep fusion deterministic cooperative data transmission method. The method comprises the following steps that: a multi-link transmission control terminal receives service data to be transmitted, divides the service data into a plurality of public network fragments and a plurality of private network fragments, transmits the public network fragments through a public network special time slot by a public network transmission module, transmits the private network fragments through a private network special time slot by a private network transmission module, and transmits the service data to be transmitted through the private network special time slot by the private network transmission module. Setting the transmission delay of each fragment; and the data recombination server receives the public network fragments and the private network fragments transmitted by the public network and the private network, classifies and stores the public network fragments and the private network fragments to corresponding cache regions, checks arrival conditions of the public network fragments and the private network fragments, and starts a retransmission process of the lost public network fragments and the lost private network fragments if the public network fragments and the private network fragments are found to be lost. According to the method provided by the invention, the transmission delay of the core service in each link can be ensured to meet the threshold requirement according to the link bandwidth capability and the service requirement, and the railway communication survivability is improved.

Description

Technical Field

[0001] This invention relates to the field of public-private network collaborative transmission technology, and in particular to a method for deep integration of public-private networks and deterministic collaborative data transmission. Background Technology

[0002] Core railway operations (such as synchronous control commands for 25,000-ton trains and CTCS-3 level train control data) have extremely high requirements for the "determinism" of transmission: latency must be ≤50ms, jitter ≤10ms, and packet loss rate ≤0.1%, otherwise it may cause asynchronous train braking and traffic safety accidents. Although current public-private network convergence solutions employ multi-link transmission (private network + public network), the lack of deterministic control mechanisms still results in transmission instability issues.

[0003] (1) Although the private network (LTE (Long Term Evolution)-R) has stable latency, its single-link bandwidth is limited and cannot support the parallel core services of multiple trains.

[0004] (2) Although the public network (4G / 5G) has a large bandwidth, it is affected by the number of users and the terrain, resulting in large latency fluctuations, and cannot support core services on its own.

[0005] (3) The industry needs to improve bandwidth and reliability through “public-private network collaborative transmission”, but existing solutions are difficult to meet deterministic requirements.

[0006] One existing "LTE-R + 4G public network" solution involves core services being transmitted via LTE-R by default, with manual switching to the 4G public network in case of LTE-R failure. The disadvantages of this solution include: ① Manual intervention is required for switching, with interruptions lasting in seconds; ② Lack of clock synchronization leads to out-of-order data reception between the public and private networks; ③ Lack of cross-link error control results in significant latency due to the need to wait for retransmissions when LTE-R packets are lost.

[0007] Another existing data offloading method for the railway 5G public-private network converged architecture involves exploring the issues of authorization and authentication in the public network core network unit and data transmission through different paths, and proposing a data offloading method. However, this method focuses on initial access authentication and offloading logic, and does not address deterministic latency guarantees, high-precision clock synchronization, or real-time error control and fast switching mechanisms across links during transmission.

[0008] The shortcomings of the above-mentioned data offloading method for the railway 5G public-private network converged architecture include: lack of deterministic latency and jitter control. The scheme does not constrain the latency and jitter of multi-link transmission, resulting in large latency fluctuations (such as when the 5G-R public network is congested) and large jitter in core services, which does not meet the requirements of "latency and jitter" for services such as railway train control.

[0009] Link switching is time-consuming and passive: Existing solutions require manual triggering or waiting for a link failure alarm before switching. The switching process requires re-establishing the connection (such as a TCP three-way handshake), resulting in long interruptions and disruptions to core services.

[0010] Low clock synchronization accuracy across multiple links: Public and private networks use independent clock sources, resulting in clock deviations. Data reception is sorted by arrival time (rather than transmission time), causing train control commands and backup data to be reassembled out of order, affecting business parsing.

[0011] Error control is only effective for a single link: Existing solutions only use retransmission mechanisms (such as TCP retransmission) for a single link. The packet loss rate of the link leads to a delay in retransmission. If the link is interrupted, there is no backup link to retransmit, and the service will fail directly, resulting in insufficient reliability.

[0012] There is no deterministic strategy for bandwidth allocation: bandwidth is allocated according to the principle of "average allocation" or "fixed allocation" without taking into account the link bandwidth capacity (e.g., 100MHz for public network bandwidth and 20MHz for private network bandwidth) and business needs, resulting in overload of narrow bandwidth links (private network) and idle resources of wide bandwidth links (public network). Summary of the Invention

[0013] The embodiments of the present invention provide a method for deep integration of deterministic collaborative data transmission in public and private networks, so as to significantly improve the determinism of business data transmission in public and private networks.

[0014] To achieve the above objectives, the present invention adopts the following technical solution.

[0015] A method for deterministic collaborative data transmission with deep integration of public and private networks includes:

[0016] The clock synchronization layer activates the GNSS dual-mode receiver module to obtain the reference clock. The PTP clock module broadcasts clock signals to public network base stations, private network base stations and receiver servers through the PTPv2 protocol to calibrate the clocks of each node.

[0017] The multi-link transmission control terminal receives the service data to be transmitted, divides the service data into several public network segments and several private network segments according to the set bandwidth ratio between the public network and the private network, and adds an identifier to each public network segment and private network segment.

[0018] The public network segment is transmitted through a dedicated time slot on the public network via a public network transmission module, and the transmission delay for each public network segment is set. The private network segment is transmitted through a dedicated time slot on the private network via a private network transmission module, and the transmission delay for each private network segment is set.

[0019] The data reassembly server receives public network fragments and private network fragments transmitted from the public network and private network, classifies and stores the public network fragments and private network fragments into corresponding cache areas, checks the arrival status of public network fragments and private network fragments, and if it finds that public network fragments and private network fragments are lost, it starts the retransmission process of lost public network fragments and private network fragments.

[0020] Preferably, the multi-link transmission control terminal receives the service data to be transmitted, divides the service data into several public network fragments and several private network fragments according to the set bandwidth ratio between the public network and the private network, and adds an identifier to each public network fragment and private network fragment, including:

[0021] The multi-link transmission control terminal receives the service data to be transmitted. Based on the consistency of transmission delay of each link and the bandwidth ratio between the public network and the private network set according to the delay requirements of the service data, the service fragmentation module in the multi-link transmission control terminal divides the service data into several public network fragments and several private network fragments according to the bandwidth ratio between the public network and the private network. The marking module in the multi-link transmission control terminal adds an identifier to each fragment, which includes: timestamp, link identifier and fragment sequence number.

[0022] The multi-link transmission control terminal sends a data fragmentation notification message to the receiving end's data reassembly server, carrying the public network fragmentation and private network fragmentation division information of the service data and the identification information of each public network fragment and private network fragment.

[0023] Preferably, the transmission of public network segments via a public network transmission module through a dedicated time slot of the public network, and the setting of a transmission delay for each public network segment; and the transmission of private network segments via a private network transmission module through a dedicated time slot of the private network, and the setting of a transmission delay for each private network segment, includes:

[0024] A multi-link transmission layer is deployed on the vehicle terminal and base stations along the route. The multi-link transmission layer includes a public network transmission module and a private network transmission module. The public network transmission module uses a deterministic scheduling algorithm to allocate dedicated time slots for public network segments and uses these dedicated time slots to transmit the public network segments. The transmission delay for each public network segment is set, and the status of the public network links is monitored in real time. If the delay of a public network link times out, the handover control layer is triggered to switch the public network service to the backup private network and update the bandwidth allocation ratio between the public network and the private network.

[0025] The private network transmission module uses a deterministic scheduling algorithm to allocate dedicated time slots for private network segments, and uses these dedicated time slots to transmit the private network segments. It sets the transmission delay for each private network segment, monitors the private network link status in real time, and if a private network link delay times out, it triggers the switching control layer to switch the private network service to the backup public network and updates the bandwidth allocation ratio between the public network and the private network.

[0026] Preferably, the step of initiating a retransmission process for the lost public network fragments and private network fragments if the loss of public network fragments and private network fragments is detected includes:

[0027] The data reassembly server receives public network fragments and private network fragments transmitted from the public network and private network, and stores them in corresponding caches according to their classification. The monitoring module in the data reassembly server checks the arrival status of each public network fragment and private network fragment based on the public network fragment and private network fragment division information and the identification information of each public network fragment and private network fragment carried in the data fragment notification message. If all public network fragments and private network fragments arrive on time, the process ends. If any public network fragment or private network fragment is detected as not arriving or arriving after a timeout, a retransmission request message carrying the sequence number information of the missing or timed-out public network fragment or private network fragment is sent to the corresponding public network transmission module or private network transmission module of the sending end. The retransmission request message carries the link identifier, fragment sequence number, timestamp, and retransmission priority of the missing or timed-out public network fragment or private network fragment. The retransmission request message is sent to the corresponding transmission module of the sending end through a low-latency signaling channel.

[0028] Upon receiving the retransmission request message, the public network transmission module or private network transmission module retransmits the corresponding public network fragment or private network fragment using idle time slots. The retransmitted fragment enjoys high-priority scheduling authority and occupies the emergency retransmission time slot in the link. After all public network fragments and private network fragments arrive at the data reconstruction server at the receiving end, the time-series reconstruction module in the data reconstruction server aligns all public network fragments and private network fragments according to timestamps, and then splices all public network fragments and private network fragments according to sequence numbers to restore the service data.

[0029] As can be seen from the technical solutions provided by the embodiments of the present invention described above, the method of the present invention can dynamically allocate public / private network bandwidth according to link bandwidth capacity and service requirements, ensuring that the transmission latency of core services on each link meets the threshold requirements. This reduces the risk of braking asynchrony caused by transmission instability, meets the rigid requirements of train synchronous control, ensures the continuity of train operation, and improves the resilience of railway communication.

[0030] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 A schematic diagram illustrating the implementation principle of a public-private network deep integration deterministic collaborative data transmission method provided in an embodiment of the present invention;

[0033] Figure 2 This is a flowchart illustrating a method for deep integration of public and private networks in deterministic collaborative data transmission, as provided in an embodiment of the present invention. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0035] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0036] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention is described. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0037] To facilitate understanding of the embodiments of the present invention, the following will provide further explanation and description with reference to the accompanying drawings and several specific embodiments. These embodiments do not constitute a limitation on the embodiments of the present invention.

[0038] Deterministic transmission: refers to the strict control of transmission latency, jitter, and packet loss rate of core services such as railways, low-altitude airspace, and power grids (such as train control, flight control commands, and wireless reconnection data) within preset thresholds (such as latency ≤ 50ms, jitter ≤ 10ms, and packet loss rate ≤ 0.1%), to meet the rigid requirements of services for transmission stability.

[0039] Public-private network collaborative transmission: Through a unified control mechanism, parallel transmission of multiple links between private network (LTE-R) and public network (4G / 5G) is achieved, while ensuring the timing consistency and data integrity of each link and avoiding service interruption due to single link failure.

[0040] This invention provides a comprehensive technical solution encompassing clock synchronization, deterministic fragmentation, multi-link transmission, cross-network reassembly, error control, and rapid handover to achieve deterministic collaborative transmission across deep public and private networks. The implementation principle of this invention's method for deep public-private network deterministic collaborative data transmission is as follows: Figure 1 As shown, it includes the following modules:

[0041] Clock synchronization layer: Composed of GNSS (Global Navigation Satellite System) receiver modules and PTP (Precision Time Protocol) clock modules, deployed at public network base stations, private network base stations, and receivers (such as vehicle-mounted terminals). GNSS provides a reference clock (accuracy ≤10ns), and the PTP clock module synchronizes the clocks of all nodes in the public / private network through the PTPv2 protocol (a railway-specific improved version), ensuring a clock deviation of <1ms. This keeps the clock deviation of each link in the public / private network within 1ms, ensuring that data is reassembled according to the transmission sequence during reception.

[0042] Data processing layer: Deployed in the multi-link transmission control terminal, including the "service fragmentation module" and the "marking module":

[0043] Fragmentation Module: Based on the public / private network link bandwidth ratio (e.g., public network bandwidth 100MHz, private network bandwidth 20MHz, ratio 5:1), the service data (e.g., 12KB train control instructions) is deterministically fragmented, that is, 10KB (5 / 6) is allocated to the public network and 2KB (1 / 6) is allocated to the private network, ensuring that the transmission latency of each link is consistent (since bandwidth is proportional to data volume, latency = data volume / bandwidth, therefore public network latency = 10KB / 100MHz = 0.8ms, private network latency = 2KB / 20MHz = 0.8ms).

[0044] The tagging module adds a "triple identifier" to each fragment: timestamp (sending time, accurate to 1ms), link identifier (public network / private network), and fragment sequence number (e.g., public network fragments 1-5, private network fragment 6), ensuring that the receiving end reassembles the fragments according to the timestamp and sequence number.

[0045] Multi-link transmission layer: Composed of public network (4G / 5G) transmission modules and private network (e.g., LTE-R) transmission modules, deployed on vehicle (e.g., vehicle-mounted, airborne) terminals and base stations along the route; the transmission modules adopt a "deterministic scheduling algorithm" to allocate dedicated time slots for core service segments (e.g., the first time slot of the LTE-R private network only transmits core segments to avoid competing with other services), ensuring stable transmission latency; at the same time, it monitors the link status (latency, packet loss rate) in real time, and if the latency of a link exceeds 40ms (with 10ms jitter redundancy reserved), the handover control layer is triggered.

[0046] Receive and Reassembly Layer: Deployed on the data reassembly server, it includes a "fragmented receive module" and a "time-series reassembly module".

[0047] Receiving module: Simultaneously receives public / private network fragments and stores them according to link identifier (public network fragment cache area, private network fragment cache area).

[0048] Reassembly module: Reassemble data according to the principle of "timestamp priority, sequence number secondary" - first sort by timestamp (to ensure that fragments with the same sending time are aligned), then concatenate by fragment sequence number (e.g., public network fragments 1-5 + private network fragment 6) to restore the original business data; if a fragment does not arrive on time (timeout time 5ms), the error control layer is triggered.

[0049] Error control layer: Deployed within the error control unit, employing a "cross-link retransmission mechanism":

[0050] When a public network fragment is detected to be lost (e.g., fragment 3 has not arrived), a "retransmission request" is sent to the private network transmission module, and the private network module immediately retransmits the fragment (using the private network's idle time slots, with a delay of ≤10ms).

[0051] If a link is interrupted (such as a public network interruption), the remaining fragments will be transmitted by another link (e.g., the private network bandwidth is temporarily expanded to 30MHz to handle 5 / 6 of the original public network data volume, with a latency of 10KB / 30MHz≈3.3ms, still satisfying the total latency ≤50ms).

[0052] Switching control layer: Deployed on the fast switching gateway, employing a "pre-establishment + fast negotiation" strategy.

[0053] Pre-establishment: During normal transmission, a connection is established in advance with a backup link (such as a private network when the public network is interrupted) (to complete protocol negotiation and authentication). The backup link is in "hot standby state" (only transmitting heartbeat packets, bandwidth usage <1%).

[0054] Fast switching: When the latency of the primary link (such as the public network) exceeds 40ms, the gateway immediately switches the service to the backup link (private network). The switching process only requires updating the link identifier (without re-establishing the connection), and the interruption time is less than 0.5s. At the same time, the switching status is fed back to the multi-link transport layer to update the bandwidth allocation ratio.

[0055] The processing flow of a public-private network deep integration deterministic collaborative data transmission method provided in this embodiment of the invention is as follows: Figure 2 As shown, the processing steps include the following:

[0056] Step S1: Clock synchronization initialization

[0057] The clock synchronization layer activates the GNSS receiving module to acquire the reference clock (accuracy 10ns); the PTP clock module broadcasts the clock signal to the public network base station, private network base station and receiving server through the PTPv2 protocol to calibrate the clock of each node; finally, the clock deviation of each node in the public / private network is controlled within 1ms (e.g., public network base station clock = reference clock + 0.5ms, private network base station clock = reference clock + 0.3ms).

[0058] Step S2: Business data fragmentation and labeling (processing latency).

[0059] The multi-link transmission control terminal receives the service data to be transmitted (such as a 12KB train control command). The service fragmentation module divides the service data into 6 fragments (5 public network fragments, 10KB each; 1 private network fragment, 2KB each) according to the public / private network bandwidth ratio (5:1). The marking module adds a triple identifier to each fragment: timestamp (such as 16:00:00.001), link identifier (public network = G, private network = Z), and the sequence numbers of the 5 public network fragments are 1-G to 5-G, and the sequence number of the 1 private network fragment is 6-Z.

[0060] The multi-link transmission control terminal can adopt an "edge cloud + virtualization" architecture, deploying sharding and tagging algorithms on edge cloud servers (rather than local hardware), supporting shared scheduling of multiple trains (such as providing sharding services for 5 trains at the same time), reducing the hardware cost per train; at the same time, the edge cloud can dynamically allocate computing resources to adapt to fluctuations in business volume.

[0061] The multi-link transmission control terminal sends a data fragmentation notification message to the receiving end's data reassembly server, carrying the public network fragmentation and private network fragmentation division information of the above-mentioned service data and the identification information of each public network fragment and private network fragment.

[0062] Step S3: Multi-link deterministic transmission (transmission delay).

[0063] The public network transmission module transmits public network segments 1-G to 5-G via dedicated time slots on the 4G / 5G public network, with a latency of 0.8ms (10KB / 100MHz). Adding the link propagation latency of 30ms, the total latency is approximately 30.8ms. The private network transmission module transmits private network segments 6-Z via dedicated time slots on the LTE-R private network, with a latency of 0.8ms (2KB / 20MHz). Adding the link propagation latency of 30ms, the total latency is approximately 30.8ms. During transmission, link latency is monitored in real time; both the public network latency (30.8ms) and the private network latency (30.8ms) are ≤40ms.

[0064] Step S4: Fragment reception and status monitoring (reception delay).

[0065] The data reassembly server receives public network fragments and private network fragments transmitted from the public network and private network, and stores them in the corresponding cache areas according to their classification. Based on the public network fragment and private network fragment division and the identification information of each public network fragment and private network fragment carried in the above data fragment notification message, the monitoring module in the data reassembly server checks the fragment arrival status: if fragments 1-G to 5-G and 6-Z all arrive on time, taking 30.8ms + 5ms for reception and processing = 35.8ms, and there is no loss, the process ends; if fragment 3-G is detected as not arriving, with a timeout of 5ms and a total timeout of 40.8ms, then step S5 is triggered.

[0066] Step S5: Cross-link error control (retransmission delay)

[0067] The error control unit detects the loss of fragment 3-G and sends a "retransmission request" to the private network transmission module. The private network module retransmits fragment 3-G using an idle time slot (data size 2KB, bandwidth 20MHz, latency = 2KB / 20MHz + propagation latency 30ms ≈ 30.8ms, plus request transmission latency of 10ms, total retransmission time ≈ 40.8ms). After the retransmitted fragment 3-G reaches the data reassembly server, the process proceeds to step S6.

[0068] The monitoring module in the data reassembly server monitors the arrival status and timestamp deviation of each fragment in real time. If a fragment fails to arrive within a preset timeout window (5ms), it is determined to be a "lost fragment." The monitoring module immediately generates a retransmission request message containing the link identifier, fragment sequence number, timestamp, and retransmission priority of the fragment, and sends it to the corresponding transmission module (public or private network) at the sending end through a low-latency signaling channel (such as a private network control channel). The retransmitted fragment enjoys high-priority scheduling rights and occupies the "emergency retransmission time slot" in the link, ensuring that its transmission latency is lower than that of normal service fragments. The sending end transmission module dynamically allocates dedicated retransmission time slots according to the current link load, avoiding competition for bandwidth with normal services.

[0069] Step S6: Data Reassembly (Reassembly Delay) The time-series reassembly module in the data reassembly server aligns all fragments according to the timestamp (16:00:00.001), and then splices them according to the sequence numbers 1-G~6-Z to restore the 12KB train control instructions; the total time for the reassembled data = transmission 30.8ms + reception 5ms + retransmission 40.8ms (if any) + reassembly 3ms ≈ 80ms. In actual retransmission, other fragments are already waiting in the buffer, so the total time = max (normal transmission delay, retransmission delay) + reassembly delay = 40.8ms + 3ms = 43.8ms ≤ 50ms, which meets the deterministic requirement.

[0070] Step S7: Fast Link Switching (Abnormal Scenario, Switching Delay)

[0071] If the multi-link transport layer detects a sudden increase in public network latency to 45ms (exceeding the threshold of 40ms), it triggers the handover control layer: the fast-switching gateway immediately switches the public network service to the backup private network (which has been pre-established), updates the bandwidth allocation ratio (the private network bandwidth is expanded to 30MHz to handle all 12KB of data, and the latency = 12KB / 30MHz + 30ms ≈ 30.4ms); the handover process only requires updating the link identifier (which takes 0.3s), and the service is uninterrupted.

[0072] The multi-link transmission layer can adopt a strategy of "multi-link concurrent transmission + traffic sharing" instead of "master-slave switching" - business data is transmitted simultaneously through public / private networks (each bearing 50% of the data volume), the receiving end takes the first arriving fragment, and the switching process is uninterrupted (because both links are transmitting).

[0073] The traffic ratio between the public and private networks is dynamically adjusted based on real-time link status (latency, packet loss rate, bandwidth utilization). For example, when link quality is balanced, bandwidth can be allocated proportionally (e.g., 1:1); if the quality of a link degrades, its load ratio is dynamically reduced, and more traffic is switched to the link with better quality. The receiving end simultaneously receives fragments from both links and sorts and selects them based on fragment identifiers (timestamp, sequence number). For the same fragment, if it arrives from both links, the fragment with lower latency is prioritized for reassembly, and redundant fragments are discarded, thereby further improving transmission efficiency and reliability.

[0074] When a link fails, another link automatically takes over 100% of the data volume, with an interruption time of approximately 0ms (data volume adjustment time only). Cross-link error control and link interruption retransmission mechanism: When a link loses packets or is interrupted, data is retransmitted through other links, keeping the overall packet loss rate below 0.1%, solving the problems of high retransmission latency and easy service failure in existing solutions.

[0075] Fast switching technology with pre-established backup links: The backup link completes protocol negotiation and authentication in advance, and only the link identifier is updated during switching. The interruption time is ≤0.5s, which solves the problem of long switching interruption time (>1s) in the existing solution and ensures business continuity.

[0076] Dedicated time slot scheduling for core services: Dedicated transmission time slots are allocated to core services in public / private network links to avoid competing for resources with other services, and jitter is controlled to ≤10ms to meet the deterministic jitter requirements of railway core services.

[0077] Significantly improved transmission determinism: core service latency ≤50ms, jitter ≤10ms, packet loss rate ≤0.1%. Compared with traditional solutions, it meets the rigid requirements of train synchronous control and reduces the risk of braking asynchrony caused by transmission instability.

[0078] The link switching interruption time is significantly reduced: the switching interruption time is ≤0.5s, compared with the existing solution (1s~30s), avoiding the interruption of core services (such as train control commands) and ensuring the continuity of train operation; for example, when the public network is interrupted, the service can switch to the private network within 0.3s without data loss.

[0079] Higher utilization of multi-link resources: The bandwidth-ratio-based sharding strategy improves the utilization of both public and private network bandwidth (e.g., all 100MHz of public network bandwidth is used for core sharding, with no idle bandwidth), reducing bandwidth resource waste compared to parallel solutions.

[0080] Enhanced resilience to link failures: The cross-link retransmission mechanism enables services to continue transmitting normally even when the packet loss rate on a single link exceeds 10%. When a link is interrupted, it can seamlessly switch to a backup link with a reliability of ≥99.999%. Compared with other solutions (service failure due to link interruption), this improves the resilience of railway communications.

[0081] Excellent compatibility and scalability: It supports flexible adaptation to 4G / 5G / 6G public networks and LTE-R / 5G-R private networks. The fragmentation ratio and latency threshold can be configured through software (without hardware modification), adapting to future railway communication network upgrades (such as when 5G-R fully replaces LTE-R, only the fragmentation ratio needs to be adjusted).

[0082] In summary, the embodiments of the present invention achieve deterministic transmission of core services: the latency of core services (train control commands) is controlled to ≤50ms, jitter ≤10ms, and packet loss rate ≤0.1%, thus meeting the requirements of train synchronous control.

[0083] Reduce link switching interruption time to less than 0.5 seconds: By pre-establishing backup links and negotiating fast protocols, proactive switching of public / private network links can be achieved (without waiting for fault alarms), ensuring service continuity.

[0084] Improve multi-link clock synchronization accuracy to within 1ms: Use GNSS+PTP protocol to unify public and private network clocks, ensuring data is reassembled according to the transmission sequence and avoiding out-of-order data.

[0085] Construct a cross-link error control mechanism: when a link loses packets or is interrupted, the lost data is resent through other links, keeping the overall packet loss rate below 0.1%.

[0086] Design a deterministic bandwidth allocation strategy: dynamically allocate public / private network bandwidth based on link bandwidth capacity and business needs to ensure that the transmission latency of core services on each link meets the threshold requirements.

[0087] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0088] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present invention.

[0089] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The apparatus and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0090] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for deterministic collaborative data transmission with deep integration of public and private networks, characterized in that, include: The clock synchronization layer activates the GNSS dual-mode receiver module to obtain the reference clock. The PTP clock module broadcasts clock signals to public network base stations, private network base stations and receiver servers through the PTPv2 protocol to calibrate the clocks of each node. The multi-link transmission control terminal receives the service data to be transmitted, divides the service data into several public network segments and several private network segments according to the set bandwidth ratio between the public network and the private network, and adds an identifier to each public network segment and private network segment. The public network segment is transmitted through a dedicated time slot on the public network via a public network transmission module, and the transmission delay for each public network segment is set. The private network segment is transmitted through a dedicated time slot on the private network via a private network transmission module, and the transmission delay for each private network segment is set. The data reassembly server receives public network fragments and private network fragments transmitted from the public network and private network, classifies and stores the public network fragments and private network fragments into corresponding cache areas, checks the arrival status of public network fragments and private network fragments, and if it finds that public network fragments and private network fragments are lost, it starts the retransmission process of lost public network fragments and private network fragments.

2. The method according to claim 1, characterized in that, The multi-link transmission control terminal receives the service data to be transmitted, divides the service data into several public network fragments and several private network fragments according to the set bandwidth ratio between the public network and the private network, and adds an identifier to each public network fragment and private network fragment, including: The multi-link transmission control terminal receives the service data to be transmitted. Based on the consistency of transmission delay of each link and the bandwidth ratio between the public network and the private network set according to the delay requirements of the service data, the service fragmentation module in the multi-link transmission control terminal divides the service data into several public network fragments and several private network fragments according to the bandwidth ratio between the public network and the private network. The marking module in the multi-link transmission control terminal adds an identifier to each fragment, which includes: timestamp, link identifier and fragment sequence number. The multi-link transmission control terminal sends a data fragmentation notification message to the receiving end's data reassembly server, carrying the public network fragmentation and private network fragmentation division information of the service data and the identification information of each public network fragment and private network fragment.

3. The method according to claim 2, characterized in that, The public network segment is transmitted through a public network transmission module via a dedicated time slot on the public network, and the transmission delay for each public network segment is set. The private network segment is transmitted via a dedicated time slot on the private network using a dedicated network transmission module. The transmission delay for each private network segment is set, including: A multi-link transmission layer is deployed on the vehicle terminal and base stations along the route. The multi-link transmission layer includes a public network transmission module and a private network transmission module. The public network transmission module uses a deterministic scheduling algorithm to allocate dedicated time slots for public network segments and uses these dedicated time slots to transmit the public network segments. The transmission delay for each public network segment is set, and the status of the public network links is monitored in real time. If the delay of a public network link times out, the handover control layer is triggered to switch the public network service to the backup private network and update the bandwidth allocation ratio between the public network and the private network. The private network transmission module uses a deterministic scheduling algorithm to allocate dedicated time slots for private network segments, and uses these dedicated time slots to transmit the private network segments. It sets the transmission delay for each private network segment, monitors the private network link status in real time, and if a private network link delay times out, it triggers the switching control layer to switch the private network service to the backup public network and updates the bandwidth allocation ratio between the public network and the private network.

4. The method according to claim 2 or 3, characterized in that, The aforementioned process of initiating a retransmission of lost public network fragments and private network fragments if such loss is detected includes: The data reassembly server receives public network fragments and private network fragments transmitted from the public network and private network, and stores them in corresponding caches according to their classification. The monitoring module in the data reassembly server checks the arrival status of each public network fragment and private network fragment based on the public network fragment and private network fragment division information and the identification information of each public network fragment and private network fragment carried in the data fragment notification message. If all public network fragments and private network fragments arrive on time, the process ends. If any public network fragment or private network fragment is detected as not arriving or arriving after a timeout, a retransmission request message carrying the sequence number information of the missing or timed-out public network fragment or private network fragment is sent to the corresponding public network transmission module or private network transmission module of the sending end. The retransmission request message carries the link identifier, fragment sequence number, timestamp, and retransmission priority of the missing or timed-out public network fragment or private network fragment. The retransmission request message is sent to the corresponding transmission module of the sending end through a low-latency signaling channel. Upon receiving the retransmission request message, the public network transmission module or private network transmission module retransmits the corresponding public network fragment or private network fragment using idle time slots. The retransmitted fragment enjoys high-priority scheduling authority and occupies the emergency retransmission time slot in the link. After all public network fragments and private network fragments arrive at the data reconstruction server at the receiving end, the time-series reconstruction module in the data reconstruction server aligns all public network fragments and private network fragments according to timestamps, and then splices all public network fragments and private network fragments according to sequence numbers to restore the service data.

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