A centerless routing knowledge synchronization method and system for deep space communication networks

Abstract

The present invention provides a decentralized routing knowledge synchronization method and system for deep space communication networks. This method, which belongs to the field of communications, includes a two-level routing table comprising a primary channel knowledge chain and a secondary channel knowledge graph. The primary channel knowledge chain, which employs lower consistency constraints, is responsible for synchronizing global routing knowledge, while the secondary channel knowledge graph, which employs higher consistency constraints, is responsible for synchronizing channel knowledge of nodes connected to the current node. This method achieves global routing knowledge synchronization in deep space communication networks through decentralized self-organization, resulting in low latency, high reliability, low power consumption, and improved robustness.

Description

Technical Field

[0001] The present invention belongs to the field of communications, and in particular relates to a centerless routing knowledge synchronization method and system for a deep space communication network. Background Art

[0002] The goal of a routing algorithm is to find a high-quality path from a source to a destination. When selecting a path, routing algorithms often consider factors such as hop count, latency, and packet transmission time. Routing algorithms can be categorized as centralized or decentralized. Centralized routing algorithms use complete, global network knowledge to calculate the lowest-cost path from a source node to a destination. These algorithms typically operate within a logically centralized controller. Because the centralized controller possesses global network knowledge, it can achieve the optimal route through more accurate calculations. In contrast, decentralized routing algorithms rely solely on information about physically connected neighbors and link costs. Routers exchange information with neighbors to iteratively and distributedly calculate the lowest-cost path. A key characteristic of these algorithms is that no node possesses complete information about network link costs; each node begins its operation based solely on the costs of its physically connected links. Decentralized routing algorithms first iteratively exchange information with neighboring nodes, then gradually determine the optimal route using a step-by-step calculation process.

[0003] The deep space communication network architecture dynamically combines diverse sensors and computing resources across planets through cloud computing, attempting to communicate with celestial bodies beyond Earth orbit, expanding space exploration resources and addressing the limitations of communications limited to Earth-orbit satellites. Compared to traditional Earth-orbit satellite communication network architectures, deep space communication networks suffer from long communication distances, high communication time costs, unstable network node locations and links, and susceptibility to interruptions. Therefore, it is not suitable for logically creating a centralized controller. Furthermore, the limited computing power of deep space communication network nodes limits the performance of the decentralized routing algorithms that require repeated iterations.

[0004] A decentralized approach to global routing knowledge synchronization can address these issues. However, the core of decentralized global routing knowledge synchronization lies in the consistency algorithm, specifically how to achieve consistent data synchronization across time-varying intersatellite link computation nodes. Traditional decentralized system designs fall into two categories. One involves electing a temporary master node to coordinate routing knowledge synchronization. However, failure of this temporary master node in such systems can cause the entire cluster system to malfunction, making them unsuitable for deep space communication networks with poor node stability. The other type of system does not elect a temporary master node, but instead relies on a vote by all nodes upon each routing state change. The drawback of this system is that voting increases the time required for routing knowledge synchronization. Therefore, developing decentralized routing state synchronization technology for deep space communication networks presents a challenge. Summary of the Invention

[0005] The purpose of the present invention is to propose a decentralized routing knowledge synchronization method and system for deep space communication networks, which realizes global routing knowledge synchronization of deep space communication networks through decentralized self-organization, with low latency, high reliability, low power consumption and better robustness.

[0006] The present invention is achieved through the following technical solutions:

[0007] A centerless routing knowledge synchronization method for a deep space communication network, comprising:

[0008] A two-level routing table with a primary channel knowledge chain and a secondary channel knowledge graph is used. The primary channel knowledge chain adopts a lower consistency constraint and is responsible for synchronizing global routing knowledge. The secondary channel knowledge graph adopts a higher consistency constraint and is responsible for synchronizing the channel knowledge of nodes connected to the current node.

[0009] Channel creation: When a new physical channel is established between planets, the node responsible for establishing the channel will perform the following steps in sequence: package the new channel information to generate a channel information description file, append the channel information description file to the end of the node's primary channel knowledge chain, broadcast the channel information description file to all nodes, and update the secondary channel knowledge graph of the node responsible for establishing the channel and the nodes connected to it. After receiving the broadcast, each node will append the channel information description file to the end of its primary channel knowledge chain.

[0010] Channel closing: The node responsible for canceling the channel checks the weight of the corresponding edge in the secondary channel knowledge graph of the channel to be canceled. If it is greater than zero, the channel closing process ends. If it is equal to zero, the node responsible for canceling the channel iteratively updates the secondary channel knowledge graph of this node and the adjacent nodes, broadcasts the cancellation link information, deletes the link corresponding to the channel in the primary channel knowledge chain of all nodes, and finally cancels the channel.

[0011] Link creation: The link creator traverses all nodes in the primary channel knowledge chain in sequence. For each node in the traversal process, if a channel needs to be created, the channel weight value in the secondary channel knowledge graph of the current node is increased by 1;

[0012] Link closing: The link closing initiator sequentially traverses all nodes in the primary channel knowledge chain. For each node in the traversal process, the channel closing operation is performed when the weight of the channel corresponding to the current node in its secondary channel knowledge graph is equal to 0.

[0013] Furthermore, the updating of the secondary channel knowledge graph of the node responsible for establishing the channel and the nodes connected to the node is specifically as follows: for the node responsible for establishing the channel, obtaining the secondary channel knowledge graph of the new node corresponding to the new channel, merging the secondary channel knowledge graph of the new node with the secondary channel knowledge graph of the node responsible for establishing the channel, and adding the channel connection between the node responsible for establishing the channel and the new node in the merged secondary channel knowledge graph; taking the node responsible for establishing the channel as the starting node, depth-first traversing its secondary channel knowledge graph at this time, notifying each node in the traversal process in turn, requiring it to obtain the secondary channel knowledge graph of the new node and merge it, and adding the channel connection between the current node and the new node.

[0014] Furthermore, the node responsible for canceling the channel iteratively updates the secondary channel knowledge graphs of the node and adjacent nodes as follows: starting from the node responsible for canceling the channel, depth-first traversing its secondary channel knowledge graph at that time, for each node in the traversal process, deleting the channel connection to be canceled in its secondary channel knowledge graph, and deleting the secondary channel knowledge graph that is not connected to the current node.

[0015] Furthermore, if a corresponding channel already exists in the current secondary channel knowledge graph, there is no need to create a channel; otherwise, a channel needs to be created.

[0016] Furthermore, a secondary channel knowledge graph of a new node corresponding to the new channel is obtained through the network.

[0017] The present invention is also achieved through the following technical solutions:

[0018] A decentralized routing knowledge synchronization system for deep space communication networks includes a two-level routing table with a primary channel knowledge chain and a secondary channel knowledge graph. The primary channel knowledge chain uses lower consistency constraints and is responsible for synchronizing global routing knowledge. The secondary channel knowledge graph uses higher consistency constraints and is responsible for synchronizing channel knowledge of nodes connected to the current node.

[0019] The system execution process is divided into four parts: channel creation, channel closing, link creation, and link closing, which are:

[0020] Channel creation: When a new physical channel is established between planets, the node responsible for establishing the channel will perform the following steps in sequence: package the new channel information to generate a channel information description file, append the channel information description file to the end of the node's primary channel knowledge chain, broadcast the channel information description file to all nodes, and update the secondary channel knowledge graph of the node responsible for establishing the channel and the nodes connected to it. After receiving the broadcast, each node will append the channel information description file to the end of its primary channel knowledge chain.

[0021] Channel closing: The node responsible for canceling the channel checks the weight of the corresponding edge in the secondary channel knowledge graph of the channel to be canceled. If it is greater than zero, the channel closing process ends. If it is equal to zero, the node responsible for canceling the channel iteratively updates the secondary channel knowledge graph of this node and the adjacent nodes, broadcasts the cancellation link information, deletes the link corresponding to the channel in the primary channel knowledge chain of all nodes, and finally cancels the channel.

[0022] Link creation: The link creator traverses all nodes in the primary channel knowledge chain in sequence. For each node in the traversal process, if a channel needs to be created, the channel weight value in the secondary channel knowledge graph of the current node is increased by 1;

[0023] Link closure: The link closure initiator traverses all nodes in the primary channel knowledge chain in sequence. For each node in the traversal process, the channel closure operation is performed when the weight of the channel corresponding to the current node in its secondary channel knowledge graph is equal to 0.

[0024] The present invention has the following beneficial effects:

[0025] 1. The present invention adopts a two-level routing table. The primary channel knowledge chain adopts lower consistency constraints, and the secondary channel knowledge graph adopts higher consistency constraints. This can reduce synchronization overhead while obtaining global channel knowledge. During execution, global routing knowledge synchronization for deep space communication is achieved in a decentralized self-organizing form. There is no need to select a temporary master node or for all nodes to vote every time the routing status changes. This meets the high anti-destruction and low power consumption requirements of deep space communication due to the complex communication environment and limited energy, and solves the routing selection problem of deep space communication networks with long distances and high latency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described in detail below with reference to the accompanying drawings.

[0027] Figure 1 Schematic diagram of the first-level channel knowledge chain of the present invention.

[0028] Figure 2 Schematic diagram of the secondary channel knowledge graph of the present invention.

[0029] Figure 3 This is the secondary channel knowledge graph before updating in the present invention.

[0030] Figure 4 This is a schematic diagram of the merged secondary channel knowledge graph before update and the secondary channel knowledge graph of the new node in the present invention.

[0031] Figure 5 This is the updated secondary channel knowledge graph of the present invention. DETAILED DESCRIPTION

[0032] The decentralized routing knowledge synchronization method for deep space communication networks includes:

[0033] A two-level routing table with a primary channel knowledge chain and a secondary channel knowledge graph is used, such as Figure 1 As shown in , the first-level channel knowledge chain is responsible for synchronizing global routing knowledge. It adopts lower consistency constraints. When a new channel is generated, the node may not be able to obtain the channel knowledge in time, but after a period of waiting, it will eventually be able to obtain the knowledge. Figure 2 As shown, the secondary channel knowledge graph adopts higher consistency constraints. It is responsible for synchronizing the channel knowledge of nodes connected to the current node and can be quickly updated when the channels connected to it change. Due to the physical space limitations of planetary computing nodes, multi-satellite collaborative networks are often small clusters. Therefore, the size of the secondary channel knowledge graph is much smaller than the primary channel knowledge chain, and the synchronization cost is low. Through the design of a two-level routing table, the synchronization overhead is reduced while obtaining global channel knowledge. The low consistency constraint and the high consistency constraint are determined by setting the constraint threshold. This setting process is based on the existing technology.

[0034] Channel creation: When a new physical channel is established between planets, the node responsible for establishing the channel will perform the following steps in sequence: package the new channel information to generate a channel information description file, append the channel information description file to the end of the node's primary channel knowledge chain, broadcast the channel information description file to all nodes, and update the secondary channel knowledge graph of the node responsible for establishing the channel and the nodes connected to it. After receiving the broadcast, each node will append the channel information description file to the end of its primary channel knowledge chain.

[0035] The channel information description file is shown in Table 1, including the starting node of the link, the destination node of the link, the link bandwidth, and the average link delay:

[0036] Table 1

[0037] name describe Node 1 Link start node Node 2 Link destination node bandwidth Link bandwidth Average latency Average link delay

[0038] The specific steps to update the secondary channel knowledge graph of the node responsible for establishing the channel and the nodes connected to the node are:

[0039] Figure 3 In the secondary channel knowledge graph shown in FIG, each node number represents the physical node ID, the edge formed between the nodes represents the channel, and the edge weight represents the number of link occupancy. Now, if new channels 1-5 are to be added, in this embodiment, the node responsible for establishing the channel is node 1 (in this embodiment, the non-new node among the two nodes involved in the new channel is selected as the node responsible for establishing the channel, and the node responsible for canceling the channel is also selected in this way). Then, for node 1, the secondary channel knowledge graph of node 5 is obtained through the network (i.e. Figure 45-6), merge the secondary channel knowledge graph of node 5 with the secondary channel knowledge graph of node 1, as shown in Figure 4 ; Then add the channel connection between node 1 and node 5 in the merged secondary channel knowledge graph (i.e. Figure 5 ); then, starting with node 1, the secondary channel knowledge graph of node 1 is traversed depth-first, and each node in the traversal process (i.e., node 2, node 3, node 7, and node 4) is notified in turn, requiring them to obtain the secondary channel knowledge graph of the new node and merge it, and add the channel connection between the current node and node 5.

[0040] Channel closing: The node responsible for canceling the channel checks the weight of the corresponding edge in the secondary channel knowledge graph of the channel to be canceled. If it is greater than zero, the channel closing process ends. If it is equal to zero, the node responsible for canceling the channel iteratively updates the secondary channel knowledge graph of this node and the adjacent nodes, broadcasts the cancellation link information, deletes the link corresponding to the channel in the primary channel knowledge chain of all nodes, and finally cancels the channel.

[0041] The node responsible for canceling the channel iteratively updates the secondary channel knowledge graph of the node and the adjacent nodes as follows: starting from the node responsible for canceling the channel, traverse its secondary channel knowledge graph at this time in depth first, and for each node in the traversal process, delete the channel connection to be canceled in its secondary channel knowledge graph, and delete the secondary channel knowledge graph that is not connected to the current node, such as deleting Figure 5 After connecting channels 1-5, node 1 can no longer reach node 6, so 5-6 needs to be deleted.

[0042] Link creation: The link creator traverses all nodes in the primary channel knowledge chain in sequence. For each node in the traversal process, if a channel needs to be created, the channel weight value in the secondary channel knowledge graph of the current node is increased by 1;

[0043] The judgment rule for whether a channel needs to be created is: if the corresponding channel already exists in the current secondary channel knowledge graph, then there is no need to create a channel; otherwise, a channel needs to be created;

[0044] Link Closure: The link closure initiator sequentially traverses all nodes in the primary channel knowledge chain. For each node in the traversal, the channel closure operation is executed when the weight of the channel corresponding to the current node in its secondary channel knowledge graph is equal to 0. The link creator and link closure initiator are determined by the application algorithm; how they are determined at the routing level is not considered.

[0045] Correspondingly, the decentralized routing knowledge synchronization system for deep space communication networks includes a two-level routing table with a primary channel knowledge chain and a secondary channel knowledge graph. The primary channel knowledge chain adopts a lower consistency constraint and is responsible for synchronizing global routing knowledge. The secondary channel knowledge graph adopts a higher consistency constraint and is responsible for synchronizing the channel knowledge of nodes connected to the current node.

[0046] The system execution process is divided into four parts: channel creation, channel closing, link creation, and link closing, which are:

[0047] Channel creation: When a new physical channel is established between planets, the node responsible for establishing the channel will perform the following steps in sequence: package the new channel information to generate a channel information description file, append the channel information description file to the end of the node's primary channel knowledge chain, broadcast the channel information description file to all nodes, and update the secondary channel knowledge graph of the node responsible for establishing the channel and the nodes connected to it. After receiving the broadcast, each node will append the channel information description file to the end of its primary channel knowledge chain.

[0048] Channel closing: The node responsible for canceling the channel checks the weight of the corresponding edge in the secondary channel knowledge graph of the channel to be canceled. If it is greater than zero, the channel closing process ends. If it is equal to zero, the node responsible for canceling the channel iteratively updates the secondary channel knowledge graph of this node and the adjacent nodes, broadcasts the cancellation link information, deletes the link corresponding to the channel in the primary channel knowledge chain of all nodes, and finally cancels the channel.

[0049] Link creation: The link creator traverses all nodes in the primary channel knowledge chain in sequence. For each node in the traversal process, if a channel needs to be created, the channel weight value in the secondary channel knowledge graph of the current node is increased by 1;

[0050] Link closure: The link closure initiator traverses all nodes in the primary channel knowledge chain in sequence. For each node in the traversal process, the channel closure operation is performed when the weight of the channel corresponding to the current node in its secondary channel knowledge graph is equal to 0.

[0051] The above description is merely a preferred embodiment of the present invention and therefore cannot be used to limit the scope of the present invention. In other words, equivalent changes and modifications made according to the scope of the patent application and the contents of the specification should still fall within the scope of the patent of the present invention.

Claims

1. A decentralized routing knowledge synchronization method for deep space communication networks, characterized by: include: A two-level routing table with a primary channel knowledge chain and a secondary channel knowledge graph is used. The primary channel knowledge chain adopts a lower consistency constraint and is responsible for synchronizing global routing knowledge. The secondary channel knowledge graph adopts a higher consistency constraint and is responsible for synchronizing the channel knowledge of nodes connected to the current node. Channel creation: When a new physical channel is established between planets, the node responsible for establishing the channel will perform the following steps in sequence: package the new channel information to generate a channel information description file, append the channel information description file to the end of the node's primary channel knowledge chain, broadcast the channel information description file to all nodes, and update the secondary channel knowledge graph of the node responsible for establishing the channel and the nodes connected to it. After receiving the broadcast, each node will append the channel information description file to the end of its primary channel knowledge chain. Channel closing: The node responsible for canceling the channel checks the weight of the corresponding edge in the secondary channel knowledge graph of the channel to be canceled. If it is greater than zero, the channel closing process ends. If it is equal to zero, the node responsible for canceling the channel iteratively updates the secondary channel knowledge graph of this node and the adjacent nodes, broadcasts the cancellation link information, deletes the link corresponding to the channel in the primary channel knowledge chain of all nodes, and finally cancels the channel. Link creation: The link creator traverses all nodes in the primary channel knowledge chain in sequence. For each node in the traversal process, if a channel needs to be created, the channel weight value in the secondary channel knowledge graph of the current node is increased by 1; Link closing: The link closing initiator sequentially traverses all nodes in the primary channel knowledge chain. For each node in the traversal process, the channel closing operation is performed when the weight of the channel corresponding to the current node in its secondary channel knowledge graph is equal to 0.

2. The method for synchronizing decentralized routing knowledge for a deep space communication network according to claim 1, characterized in that: The updating of the secondary channel knowledge graph of the node responsible for establishing the channel and the nodes connected to the node is specifically as follows: for the node responsible for establishing the channel, obtaining the secondary channel knowledge graph of the new node corresponding to the new channel, merging the secondary channel knowledge graph of the new node with the secondary channel knowledge graph of the node responsible for establishing the channel, and adding the channel connection between the node responsible for establishing the channel and the new node in the merged secondary channel knowledge graph; taking the node responsible for establishing the channel as the starting node, depth-first traversing its secondary channel knowledge graph at this time, notifying each node in the traversal process in turn, requiring it to obtain the secondary channel knowledge graph of the new node and merge it, and adding the channel connection between the current node and the new node.

3. The method for synchronizing decentralized routing knowledge for a deep space communication network according to claim 1, characterized in that: The node responsible for canceling the channel iteratively updates the secondary channel knowledge graphs of the node and adjacent nodes as follows: starting from the node responsible for canceling the channel, depth-first traversing its secondary channel knowledge graph at that time, for each node in the traversal process, deleting the channel connection to be canceled in its secondary channel knowledge graph, and deleting the secondary channel knowledge graph that is not connected to the current node.

4. A method for synchronizing decentralized routing knowledge in a deep space communication network according to claim 1, 2 or 3, characterized in that: If the corresponding channel already exists in the current secondary channel knowledge graph, there is no need to create a channel; otherwise, a channel needs to be created.

5. The method for synchronizing decentralized routing knowledge for a deep space communication network according to claim 2 or 3, characterized in that: A secondary channel knowledge graph of a new node corresponding to the new channel is obtained through the network.

6. A decentralized routing knowledge synchronization system for deep space communication networks, characterized by: It includes a two-level routing table with a primary channel knowledge chain and a secondary channel knowledge graph. The primary channel knowledge chain adopts a lower consistency constraint and is responsible for synchronizing global routing knowledge. The secondary channel knowledge graph adopts a higher consistency constraint and is responsible for synchronizing channel knowledge of nodes connected to the current node. The system execution process is divided into four parts: channel creation, channel closing, link creation, and link closing, which are: Channel creation: When a new physical channel is established between planets, the node responsible for establishing the channel will perform the following steps in sequence: package the new channel information to generate a channel information description file, append the channel information description file to the end of the node's primary channel knowledge chain, broadcast the channel information description file to all nodes, and update the secondary channel knowledge graph of the node responsible for establishing the channel and the nodes connected to it. After receiving the broadcast, each node will append the channel information description file to the end of its primary channel knowledge chain. Channel closing: The node responsible for canceling the channel checks the weight of the corresponding edge in the secondary channel knowledge graph of the channel to be canceled. If it is greater than zero, the channel closing process ends. If it is equal to zero, the node responsible for canceling the channel iteratively updates the secondary channel knowledge graph of this node and the adjacent nodes, broadcasts the cancellation link information, deletes the link corresponding to the channel in the primary channel knowledge chain of all nodes, and finally cancels the channel. Link creation: The link creator traverses all nodes in the primary channel knowledge chain in sequence. For each node in the traversal process, if a channel needs to be created, the channel weight value in the secondary channel knowledge graph of the current node is increased by 1; Link closure: The link closure initiator traverses all nodes in the primary channel knowledge chain in sequence. For each node in the traversal process, the channel closure operation is performed when the weight of the channel corresponding to the current node in its secondary channel knowledge graph is equal to 0.

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