Multi-hop wireless network system, tree network topology maintenance method and member nodes

Abstract

The embodiment of the invention provides a multi-hop wireless network system comprising a plurality of network nodes, a tree network topology maintenance method and member nodes. A multi-hop wireless network system includes a first member node. And the first member node is connected to the control node in the plurality of network nodes through the first relay node in the tree topology network formed by the plurality of network nodes, and operates as a second relay node. The first member node is configured to, in response to determining that a connection between the first relay node and the first member node is disconnected, stop operating as a second relay node.

Description

Technical Field

[0001] The present invention relates to a technique for determining a network topology, and more particularly to a multi-hop wireless network system, a method for maintaining a tree-shaped network topology, and a first member node. Background Art

[0002] In the environment of multi-hop wireless networks (especially in industrial environments), the wireless environment is usually very complex and full of interference. Therefore, in such cases, establishing a tree-shaped network topology is usually more challenging than establishing a star-shaped network topology.

[0003] In a star-shaped network topology, all nodes communicate directly with a central hub, which can simplify network management and reduce interference. On the contrary, since a tree-shaped network topology involves a hierarchical structure formed by multiple interconnected nodes, establishing and maintaining such a hierarchical structure may be more complex. Moreover, interference in the network may also affect the reliability of multi-hop connections. Summary of the Invention

[0004] In view of this, the present invention provides a multi-hop wireless network system, a method for maintaining a tree-shaped network topology, and a first member node, which can be used to solve the above technical problems.

[0005] An embodiment of the present invention provides a multi-hop wireless network system including a plurality of network nodes, including a first member node. The first member node is connected to a control node among the plurality of network nodes through a first relay node in a tree-shaped topology network formed by the plurality of network nodes, and operates as a second relay node, wherein the first member node is configured to: in response to determining that the connection line between the first relay node and the first member node is disconnected, stop operating as the second relay node.

[0006] An embodiment of the present invention provides a method for maintaining a tree-shaped network topology, which is executed by a first member node among a plurality of network nodes of a multi-hop wireless network system, wherein the first member node is connected to a control node among the plurality of network nodes through a first relay node in a tree-shaped topology network formed by the plurality of network nodes, and operates as a second relay node. The method includes: in response to determining that the connection line between the first relay node and the first member node is disconnected, the first member node stops operating as the second relay node.

[0007] An embodiment of the present invention provides a first member node, which is connected to a control node among a plurality of network nodes through a first relay node in a tree-shaped topology network formed by the plurality of network nodes, and operates as a second relay node, wherein the first member node is configured to execute: in response to determining that the connection line between the first relay node and the first member node is disconnected, stop operating as the second relay node. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0009] Figure 1 It is a schematic diagram of a control node illustrated according to an embodiment of the present invention.

[0010] Figure 2 It is a flowchart of a method for updating a network topology illustrated according to an embodiment of the present invention.

[0011] Figure 3 It is a schematic diagram of establishing an initial tree - shaped network topology illustrated according to an embodiment of the present invention.

[0012] Figure 4 It is a flowchart of updating a tree - shaped network topology illustrated according to the first embodiment of the present invention.

[0013] Figures 5A to 5B It is an application scenario diagram illustrated according to the first embodiment of the present invention.

[0014] Figure 6 It is a flowchart of updating a tree - shaped network topology illustrated according to the second and third embodiments of the present invention.

[0015] Figures 7A to 7C It is an application scenario diagram illustrated according to the second embodiment of the present invention.

[0016] Figures 8A to 8C It is an application scenario diagram illustrated according to the third embodiment of the present invention.

[0017] Figures 9A to 9E It is a schematic diagram of inappropriate connection methods of each remote node illustrated according to an embodiment of the present invention.

[0018] Figure 10 It is a method for maintaining a tree - shaped network topology illustrated according to the fourth embodiment of the present invention.

[0019] Figures 11A to 11D It is an application scenario diagram illustrated according to the fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0021] Please refer to Figure 1, which is a schematic diagram of a control node illustrated according to an embodiment of the present invention. In different embodiments, the control node 100 can be implemented, for example, as various intelligent devices and / or computer devices, but is not limited thereto. In some embodiments, the control node 100 can belong to a multi-hop wireless network system including multiple network nodes.

[0022] In one embodiment, the control node 100 is, for example, a multi-point relay (MPR) among the multiple network nodes and can be used to manage one or more member nodes in the multi-hop wireless network system, where each member node is, for example, other network nodes other than the control node 100.

[0023] In some embodiments, the one or more member nodes are, for example, mesh access points (MAPs) in the multi-hop wireless network system. Additionally, in one embodiment, each member node is connected to an external network only through the control node 100, where the external network includes, for example, a control center such as a Supervisory Control and Data Acquisition system, but is not limited thereto.

[0024] In different embodiments, the control node 100 can be predefined or determined by the multiple network nodes through a specific competition mechanism, but is not limited thereto.

[0025] In Figure 1 , the control node 100 includes a storage circuit 102 and a processor 104.

[0026] The storage circuit 102 is, for example, any type of fixed or removable random access memory (RAM), read-only memory (ROM), flash memory, hard disk, or other similar devices or a combination of these devices, and can be used to record multiple program codes or modules.

[0027] The processor 104 is coupled to the storage circuit 102 and can be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor, multiple microprocessors, one or more microprocessors combined with digital signal processor cores, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array circuit (FPGA), any other kind of integrated circuit, a state machine, a processor based on an advanced RISC machine (ARM), and the like. In an embodiment of the present invention, each network node may have the same or similar structure.

[0028] In an embodiment of the present invention, the processor 104 can access the modules and program codes recorded in the storage circuit 102 to implement the method for updating the network topology proposed by the present invention, and the details are described in detail below.

[0029] Please refer to Figure 2 , which is a flowchart of the method for updating the network topology illustrated according to an embodiment of the present invention. The method of this embodiment can be executed by Figure 1 the control node 100, and the details of each step are described below in conjunction with Figure 1 the components shown. Figure 2 the details of each step.

[0030] In step S210, the processor 104 establishes a tree-shaped network topology including the plurality of network nodes. In different embodiments, the processor 104 and other member nodes can establish an initial tree-shaped network topology based on any existing algorithm for establishing a network topology.

[0031] Please refer to Figure 3 , which is a schematic diagram of establishing an initial tree-shaped network topology illustrated according to an embodiment of the present invention.

[0032] In Figure 3 , it is assumed that the multi-hop wireless network system 300 includes network nodes such as the control node 100 (e.g., MPR) and member nodes 11, 12, 13, 21, 22, 23, 31, 32, 33, 34 (e.g., MAP), and the control node 100 and the shown member nodes can establish an initial tree-shaped network topology 310 based on a certain existing algorithm.

[0033] From Figure 3It can be seen that each member node can be directly connected to the control node 100 in the tree - shaped network topology 310, or indirectly connected to the control node 100 through other member nodes. For example, member nodes 11, 13, 21, 22, 31 can be directly connected to the control node 100.

[0034] In addition, member nodes 12, 23, 32, 33, 34 can be indirectly connected to the control node 100 through other member nodes. For example, member node 12 can be indirectly connected to the control node 100 through member node 11. In this case, member node 11 can be regarded as the relay node of member node 12. Or, member node 11 can also be called the parent node of member node 12, and member node 12 can be called the child node of member node 11.

[0035] In one embodiment, member node 11 can be connected to the wireless terminal interface of member node 12 through its own access point interface to act as the relay node and / or parent node of member node 12. From another perspective, member node 12 can act as a wireless terminal served by member node 11, and member node 11 can provide the access point function and act as the access point serving member node 12. That is, the child node can act as a wireless terminal served by the parent node, and the parent node can act as the access point serving the child node.

[0036] For another example, member node 23 can be indirectly connected to the control node 100 through member node 22. In this case, member node 22 can be regarded as the relay node of member node 23. Or, member node 22 can also be called the parent node of member node 23, and member node 23 can be called the child node of member node 22.

[0037] In one embodiment, member node 22 can be connected to the wireless terminal interface of member node 23 through its own access point interface to act as the relay node and / or parent node of member node 23. From another perspective, member node 23 can act as a wireless terminal served by member node 22, and member node 22 can provide the access point function and act as the access point serving member node 23.

[0038] In addition, a member node acting as a child node can also act as a relay node (i.e., a parent node) of other member nodes at the same time. For example, in addition to acting as the child node of member node 31, member node 32 can also act as the relay node (i.e., the parent node) of member node 34 at the same time.

[0039] However, Figure 3Some of the member nodes in may be connected to the control node 100 in a manner with lower transmission quality and / or unreliability due to the algorithm content used. For example, although member nodes 13 and 22 are relatively far from the control node 100, they are configured to be directly connected to the control node 100 in the tree network topology 310 established based on the existing algorithm. In this case, it may cause the member nodes 13 and 22 to fail to achieve better transmission quality and / or reliability.

[0040] Based on this, the control node 100 can update the tree network topology 310 through subsequent steps S220 and S230 to attempt to adjust the connection manner between the member nodes 13, 22, and / or other member nodes and the control node 100, thereby improving the transmission quality and / or reliability.

[0041] In step S220, the processor 104 obtains the signal scanning results of each network node.

[0042] In one embodiment, each network node can send a broadcast signal, and this broadcast signal can include the identity information of the network node itself. For example, the control node 100 can send a broadcast signal including the identity information of the control node 100, and Figure 3 each member node in can correspondingly detect the signal quality index of the broadcast signal from the control node 100 and establish a corresponding signal scanning result accordingly. Another example is that the member node 11 can send a broadcast signal including the identity information of the member node 11, and Figure 3 the control node 100 and other member nodes in can correspondingly detect the signal quality index of the broadcast signal from the member node 11 and establish a corresponding signal scanning result accordingly.

[0043] Based on this, in the embodiments of the present invention, the signal scanning results of each network node can indicate the signal quality indexes of other network nodes. For example, in the signal scanning result established by the control node 100, it can include, for example, the individual signal quality indexes of one or more of the member nodes 11, 12, 13, 21, 22, 23, 31, 32, 33, 34. Another example is that in the signal scanning result established by the member node 11, it can include, for example, the individual signal quality indexes of one or more of the control node 100, member nodes 12, 13, 21, 22, 23, 31, 32, 33, 34. In one embodiment, the content of the signal scanning results established by other member nodes can be deduced according to the above teachings and will not be elaborated here.

[0044] In one embodiment, the signal scanning results established by each network node can be implemented in the form of a list, which can record other network nodes and their corresponding signal quality indicators, for example. In different embodiments, the signal quality indicators may include, for example, signal strength, signal strength index, signal range index, etc. In addition, the signal quality indicators of each network node may further include, for example, the GPS location information corresponding to each network node, satellite signal strength, etc., but are not limited thereto.

[0045] In one embodiment, the control node 100 directly or indirectly obtains the signal scanning results of each member node through the tree - shaped network topology 310. For example, since Figure 3 the member nodes 11, 13, 21, 22, 31 in are directly connected to the control node 100, the control node 100 can directly obtain the corresponding signal scanning results from the member nodes 11, 13, 21, 22, 31.

[0046] In addition, since Figure 3 the member nodes 12, 23, 32, 33, 34 in are indirectly connected to the control node 100 through other member nodes, the control node 100 can indirectly obtain the signal scanning results of each member node 12, 23, 32, 33, 34. For example, the control node 100 can obtain the signal scanning result of the member node 12 from the member node 12 through the member node 11. Another example is that the control node 100 can obtain the signal scanning result of the member node 23 from the member node 23 through the member node 22, but is not limited thereto.

[0047] After that, in step S230, the processor 104 updates the tree - shaped network topology 310 based on the signal scanning results of each network node.

[0048] In an embodiment of the present invention, step S230 may include one or more of the following first, second, and third embodiments, which will be further described below.

[0049] Please refer to Figure 4 which is a flowchart of updating the tree - shaped network topology illustrated according to the first embodiment. In addition, to make the first embodiment easy to understand, the following will be further supplemented with Figures 5A to 5B for illustration, where Figures 5A to 5B is an application scenario diagram illustrated according to the first embodiment of the present invention.

[0050] In step S410, in response to determining that the signal scanning result of the control node 100 indicates the existence of a first member node and a second member node among the member nodes, the processor 104 updates the tree - shaped network topology 310 by controlling each first member node to be directly connected to the control node 100.

[0051] In one embodiment, the signal quality index of each first member node in the signal scanning result of the control node 100 meets a first preset condition, and the signal quality index of each second member node in the signal scanning result of the control node 100 does not meet the first preset condition.

[0052] In one embodiment, if the signal strength of a certain member node in the signal scanning result of the control node 100 is not lower than a preset strength threshold (for example, -70 dBm), the processor 104 may determine that the signal quality index of this member node in the signal scanning result of the control node 100 meets the first preset condition; otherwise, it may be determined that the signal quality index of this member node in the signal scanning result of the control node 100 does not meet the first preset condition, but it is not limited thereto.

[0053] In Figure 5A it, the signal transmission ranges of each network node corresponding to the preset strength threshold can be depicted as corresponding solid / dashed circular ranges. For example, for each of the member nodes 11, 21, and 31 located in the signal transmission range 100a of the control node 100 (which is, for example, a circular range centered on the control node 100), the signal strength of the broadcast signal from the control node 100 detected by each of the member nodes 11, 21, and 31 is not lower than the preset strength threshold. To give another example, for the member node 12 and the control node 100 located in the signal transmission range 11a of the member node 11 (which is, for example, a circular range centered on the member node 11), the signal strength of the broadcast signal from the member node 11 detected by the member node 12 and the control node 100 is not lower than the preset strength threshold.

[0054] In addition, for another node B located outside the signal transmission range of a certain node A, it does not mean that this another node B cannot receive the signal from node A, but only that the signal strength of the signal from node A received by node B may be lower than the preset strength threshold. For example, although Figure 5A the member node 33 in it is not located within the signal transmission range 100a of the control node 100, this does not necessarily mean that the member node 33 cannot receive the signal from the control node 100, but may only mean that the signal strength of the signal received by the member node 33 from the control node 100 is lower than the preset strength threshold, but it is not limited thereto.

[0055] In Figure 5AIn this scenario, since the control node 100 is within the signal transmission range corresponding to the member nodes 11, 21, and 31, the signal strength of the member nodes 11, 21, and 31 in the signal scanning result of the control node 100 should not be lower than the preset strength threshold. In this case, the processor 104 can determine that the signal quality indicators of the member nodes 11, 21, and 31 in the signal scanning result of the control node 100 meet the first preset condition, and then determine the member nodes 11, 21, and 31 as the above-mentioned first member nodes.

[0056] Accordingly, the processor 104 can update the tree network topology 310 by controlling each member node 11, 21, and 31 to be directly connected to the control node 100, as Figure 5B shown.

[0057] In addition, since the control node 100 is not within the signal transmission range corresponding to the member nodes 12, 13, 22, 23, 32, 33, and 34, the signal strength of the member nodes 12, 13, 22, 23, 32, 33, and 34 in the signal scanning result of the control node 100 should be lower than the preset strength threshold. In this case, the processor 104 can determine that the signal quality indicators of the member nodes 12, 13, 22, 23, 32, 33, and 34 in the signal scanning result of the control node 100 do not meet the first preset condition, and then determine the member nodes 12, 13, 22, 23, 32, 33, and 34 as the above-mentioned second member nodes.

[0058] After that, in step S420, the processor 104 can label the first member nodes as belonging to the updated nodes (i.e., the member nodes whose connection methods have been optimized), and label the second member nodes as belonging to the unupdated nodes (i.e., the member nodes whose connection methods have not been optimized). In Figure 5B this scenario, the processor 104 can label the member nodes 11, 21, and 31 as belonging to the updated nodes, and label the member nodes 12, 13, 22, 23, 32, 33, and 34 as belonging to the unupdated nodes.

[0059] In the embodiments of the present invention, the updated nodes can be understood as the member nodes that have been connected to the control node 100 in a better way (such as higher transmission quality and / or reliability), and the unupdated nodes can be understood as the member nodes that may not have been connected to the control node 100 in a better way, but this is not limited thereto.

[0060] Through the content of the first embodiment, the processor 104 can determine which member nodes are more suitable to be directly connected to the control node 100, and accordingly control these member nodes to be directly connected to the control node 100. After that, the processor 104 can then execute the means of the second and third embodiments.

[0061] Please refer to Figure 6, which is a flowchart of updating the tree network topology illustrated according to the second and third embodiments. In Figure 6 this, the processor 104 can implement the content of the second embodiment by executing steps S610 to S650, and implement the content of the third embodiment by executing steps S660 to S680.

[0062] In step S610, in the i-th stage, the processor 104 obtains a first reference node marked as a node to be updated in the (i - 1)-th stage, where i is an index value greater than or equal to 1. In step S620, the processor 104 determines whether the signal scanning result of each first reference node indicates the existence of a third member node in the unupdated nodes, where the signal quality index of each third member node in the signal scanning result of the corresponding first reference node satisfies the first preset condition.

[0063] In step S630, the processor 104 updates the tree network topology by controlling each third member node to be directly connected to the corresponding first reference node.

[0064] In step S640, the processor 104 marks the third member node as a node to be updated, and in step S650, increments i by 1, and then returns to step S620.

[0065] For ease of understanding, the details of the second embodiment will be supplemented below with Figures 7A to 7C explanation, where Figures 7A to 7C is an application scenario diagram illustrated according to the second embodiment of the present invention.

[0066] In Figure 7A this scenario, it is assumed that the processor 104 has just completed the means of the first embodiment and determined the tree network topology 310 as shown in Figure 5B . In this case, the processor 104 can continue to execute the means of the second embodiment.

[0067] When starting the second embodiment, the initial value of i can be set to 1. In this case, the processor 104 can determine the first member node in the first embodiment as the first reference node in step S610. That is, when i is 1, the processor 104 can determine the Figure 7A member nodes 11, 21, 31 in as the first reference nodes in step S610.

[0068] After that, the processor 104 can determine in step S620 whether the signal scanning results of the member nodes 11, 21, 31 indicate the existence of a third member node in the unupdated nodes (for example, member nodes 12, 13, 22, 23, 32, 33, 34).

[0069] In Figure 7AAmong them, since member node 12 is within the signal transmission range corresponding to member node 11, the signal strength of member node 12 in the signal scanning result of member node 11 should not be lower than the preset strength threshold. In this case, the processor 104 can determine that the signal quality index of member node 12 in the signal scanning result of member node 11 meets the first preset condition, and then determine member node 12 as the third member node corresponding to member node 11.

[0070] In addition, since member node 22 is within the signal transmission range corresponding to member node 21, the signal strength of member node 22 in the signal scanning result of member node 21 should not be lower than the preset strength threshold. In this case, the processor 104 can determine that the signal quality index of member node 22 in the signal scanning result of member node 21 meets the first preset condition, and then determine member node 22 as the third member node corresponding to member node 21.

[0071] Based on this, when i is 1, the determination result of the processor 104 in step S620 should be "yes", and it can continue to execute step S630 to update the tree network topology 310 by controlling each third member node to be directly connected to the corresponding first reference node.

[0072] In Figure 7A this scenario, the processor 104 can control member node 12 to be directly connected to the corresponding first reference node (i.e., member node 11), and control member node 22 to be directly connected to the corresponding first reference node (i.e., member node 21) to update the tree network topology 310.

[0073] After that, the processor 104 can label member nodes 12 and 22 as belonging to the updated nodes in step S640. In this case, the unupdated nodes will be adjusted accordingly to include 13, 23, 32, 33, and 34. Then, the processor 104 can increase i by 1 (i.e., i = 2) in step S650 and return to step S620.

[0074] Please refer to Figure 7B , when i is equal to 2, the processor 104 can obtain the first reference nodes labeled as belonging to the updated nodes in the first (i.e., i - 1) stage. Since member nodes 12 and 22 are labeled as updated nodes in the first stage, the processor 104 can accordingly determine member nodes 12 and 22 as the first reference nodes considered in the second stage.

[0075] After that, the processor 104 can determine in step S620 whether the signal scanning results of member nodes 12 and 22 indicate the existence of third member nodes among the unupdated nodes (e.g., member nodes 13, 23, 32, 33, 34).

[0076] In Figure 7B Figure 7B , since member node 13 is within the signal transmission range corresponding to member node 12, the signal strength of member node 13 in the signal scan result of member node 12 should not be lower than a preset strength threshold. In this case, the processor 104 can determine that the signal quality index of member node 13 in the signal scan result of member node 12 meets the first preset condition, and then determine member node 13 as the third member node corresponding to member node 12.

[0077] In addition, since member node 23 is within the signal transmission range corresponding to member node 22, the signal strength of member node 23 in the signal scan result of member node 22 should not be lower than a preset strength threshold. In this case, the processor 104 can determine that the signal quality index of member node 23 in the signal scan result of member node 22 meets the first preset condition, and then determine member node 23 as the third member node corresponding to member node 22.

[0078] Based on this, when i is 2, the determination result of the processor 104 in step S620 should be "yes", and it can continue to execute step S630 to update the tree network topology 310 by controlling each third member node to be directly connected to the corresponding first reference node.

[0079] In Figure 7B Figure 7B , the processor 104 can control member node 13 to be directly connected to the corresponding first reference node (i.e., member node 12), and control member node 23 to be directly connected to the corresponding first reference node (i.e., member node 22) to update the tree network topology 310.

[0080] After that, the processor 104 can mark member nodes 13 and 23 as belonging to the updated nodes in step S640. In this case, the unupdated nodes will be adjusted accordingly to include 32, 33, and 34. Then, the processor 104 can increment i by 1 (i.e., i = 3) in step S650 and return to step S620.

[0081] When i is equal to 3, the processor 104 can obtain the first reference nodes marked as belonging to the updated nodes in the second (i.e., i - 1) stage. Since member nodes 13 and 23 are marked as updated nodes in the second stage, the processor 104 can accordingly determine member nodes 13 and 23 as the first reference nodes considered in the third stage.

[0082] After that, the processor 104 can determine in step S620 whether the signal scan results of each of member nodes 13 and 23 indicate the existence of a third member node among the unupdated nodes (e.g., member nodes 32, 33, and 34).

[0083] From Figure 7B it can be seen that the signal strengths of member nodes 13 and 23 do not reach the preset strength threshold for member nodes 32, 33, and 34. Therefore, the determination result of the processor 104 in step S620 should be "no". In this case, member nodes 32, 33, and 34 can be referred to as remote nodes as shown in Figure 7C . And the processor 104 can process these remote nodes by implementing the means of the third embodiment (i.e., steps S660 to S680) to make these remote nodes integrate into the tree network topology 310 in a more suitable manner.

[0084] From another perspective, the processor 104 can also be understood as, when determining that the unupdated nodes only include remote nodes not located within the signal transmission range of any updated node, correspondingly processing these remote nodes by implementing the means of the third embodiment (i.e., steps S660 to S680), but it is not limited thereto.

[0085] In step S660, in the i-th stage, the processor 104 finds second reference nodes among the unupdated nodes, where the signal scanning results of each second reference node include fourth member nodes belonging to updated nodes.

[0086] In step S670, the processor 104 updates the tree network topology by controlling each second reference node to be directly connected to the corresponding fourth member node.

[0087] In step S680, the processor 104 marks each second reference node as belonging to updated nodes, increments i by 1, and returns to step S660.

[0088] In the third embodiment, the processor 104 can recursively execute steps S660 to S680 until each member node is marked as an updated node.

[0089] To make the third embodiment easier to understand, the details of the third embodiment will be supplemented below, where Figures 8A to 8C is an application scenario diagram illustrated according to the third embodiment of the present invention. Figures 8A to 8C In

[0090] In Figure 8A , the illustrated scenario can be the same as the scenario in Figure 7C , that is, the scenario where i is equal to 3. In this case, when executing step S660, the processor 104 can find second reference nodes among member nodes 32, 33, and 34 (i.e., unupdated nodes).

[0091] In Figure 8AIn a scenario, assuming that the signal scanning result of member node 32 only includes member node 31 which belongs to the updated nodes, the processor 104 may determine member node 31 as the fourth member node corresponding to member node 32. In another embodiment, assuming that the signal scanning result of member node 32 further includes other updated nodes, the processor 104 may select one of these updated nodes with the best signal quality metric (e.g., the highest signal strength and higher than the signal strength lower limit value (e.g., -70 dBm or SNR 35 dB)) as the fourth member node corresponding to member node 32, but it is not limited thereto.

[0092] In addition, assuming that the signal scanning result of member node 33 also only includes member node 31 which belongs to the updated nodes, the processor 104 may further determine member node 31 as the fourth member node corresponding to member node 33. In another embodiment, assuming that the signal scanning result of member node 33 further includes other updated nodes, the processor 104 may select the one with the highest signal strength and higher than the signal strength lower limit value from these updated nodes as the fourth member node corresponding to member node 33, but it is not limited thereto.

[0093] In Figure 8A Since both member nodes 32 and 33 have corresponding fourth member nodes (i.e., member node 31), the processor 104 may determine member nodes 32 and 33 as the second reference nodes considered in step S660.

[0094] After that, the processor 104 may execute step S670 to control member node 32 to directly connect to the corresponding fourth member node (i.e., member node 31), and control member node 33 to directly connect to the corresponding fourth member node (i.e., member node 31), so as to update the tree network topology 310 to Figure 8A the state shown.

[0095] Next, the processor 104 may execute step S680 to mark member nodes 32 and 33 as belonging to the updated nodes, increment i by 1 (i.e., i = 4), and return to step S660.

[0096] Please refer to Figure 8B , which corresponds to the scenario where i is equal to 4. In this case, when executing step S660, the processor 104 may find the second reference node among member node 34 (i.e., the unupdated node).

[0097] In Figure 8BIn a scenario, assuming that the signal scanning result of member node 34 only includes member node 32 which belongs to an updated node, the processor 104 may determine that member node 32 is the fourth member node corresponding to member node 34. In another embodiment, assuming that the signal scanning result of member node 34 further includes other updated nodes, the processor 104 may select, from these updated nodes, the one with the highest signal strength and higher than the signal strength lower limit value as the fourth member node corresponding to member node 34, but it is not limited thereto.

[0098] In Figure 8B , since member node 34 has a corresponding fourth member node (i.e., member node 32), the processor 104 may determine that member node 34 is the second reference node considered in step S660.

[0099] After that, the processor 104 may execute step S670 to control member node 34 to directly connect to the corresponding fourth member node (i.e., member node 32) to update the tree network topology 310 to Figure 8B the state shown.

[0100] Next, the processor 104 may execute step S680 to label member node 34 as belonging to the updated nodes. At this time, since each member node has been labeled as an updated node, the processor 104 may determine that the content of the third embodiment has been completed and may no longer recursively execute steps S660 to S680, but it is not limited thereto.

[0101] In this case, the fully updated tree network topology 310 may have the state as Figure 8C shown. From Figure 3 and Figure 8C , it can be seen that in the updated tree network topology 310, member node 13 is adjusted from directly connecting to control node 100 to indirectly connecting to control node 100 through member nodes 12 and 11 in sequence. Similarly, member node 22 is adjusted from directly connecting to control node 100 to indirectly connecting to control node 100 through member node 21.

[0102] Therefore, in Figure 8C , member nodes 13 and 22 can obtain better transmission quality and / or reliability. In addition, since member nodes 32, 33, and 34 (i.e., the above-mentioned remote nodes) are farther away from control node 100 and member nodes of other non-remote nodes, in the initial tree network topology determined in step S210, member nodes 32, 33, and 34 may be connected to control node 100 in a relatively inappropriate manner.

[0103] However, since the embodiments of the present invention can determine a better connection method for the above-mentioned remote nodes through the third embodiment, the transmission quality and / or reliability of each remote node can also be preferably ensured.

[0104] To make the above concepts clearer, the following is supplemented with Figures 9A to 9E for illustration, where Figures 9A to 9E is a schematic diagram of inappropriate connection methods of each remote node illustrated according to the embodiments of the present invention.

[0105] In Figure 9A , it is assumed that the member node 34 is arranged to be connected to the control node 100 through the member node 31 in step S210. In this case, the member node 34 may not achieve better transmission quality and / or reliability due to the too long distance between the member node 34 and the member node 31.

[0106] In Figure 9B , it is assumed that the member node 34 is arranged to be connected to the control node 100 through the member node 33 in step S210. In this case, the member node 34 may not achieve better transmission quality and / or reliability due to the too long distance between the member node 34 and the member node 33.

[0107] In Figure 9C , it is assumed that the member node 32 is arranged to be connected to the control node 100 through the member nodes 34 and 31 in sequence in step S210. In this case, the member node 34 may not achieve better transmission quality and / or reliability due to the too long distance between the member node 34 and the member node 31. Additionally, the member node 32 may also have a longer transmission delay due to being connected to the control node 100 in a relatively inappropriate manner.

[0108] In Figure 9D , it is assumed that the member node 33 is arranged to be connected to the control node 100 through the member nodes 34 and 31 in sequence in step S210. In this case, the member node 34 may not achieve better transmission quality and / or reliability due to the too long distance between the member node 34 and the member node 31. Additionally, the member node 33 may also have a longer transmission delay due to being connected to the control node 100 in a relatively inappropriate manner.

[0109] In Figure 9E , it is assumed that both the member nodes 32 and 33 are arranged to be connected to the control node 100 through the member nodes 34 and 31 in sequence in step S210. In this case, the member node 34 may not achieve better transmission quality and / or reliability due to the too long distance between the member node 34 and the member node 31. Additionally, the member nodes 32 and 33 may also have a longer transmission delay due to being connected to the control node 100 in a relatively inappropriate manner.

[0110] However, in the embodiments of the present invention, since each remote node (such as member nodes 32, 33, 34) can be connected to the control node 100 in a better manner via the third embodiment, better transmission quality and / or reliability can be achieved for each remote node.

[0111] In some embodiments, the control node 100 may execute the Figure 2 method shown to update the tree network topology 310 regularly / irregularly each time the signal scanning results of one or more of the multiple network nodes are obtained.

[0112] In the embodiments of the present invention, when a member node operating as a relay node (i.e., a parent node) cannot normally serve the corresponding child node due to a failure or other reasons, the operation of itself and the child node may be seriously affected.

[0113] Therefore, the embodiments of the present invention also propose a method for maintaining the tree network topology, which can be used to solve the above technical problems.

[0114] Please refer to Figure 10 , which is a method for maintaining the tree network topology illustrated according to the fourth embodiment of the present invention. The method of this embodiment can be executed by any member node (hereinafter referred to as the first member node) in the multi-hop wireless network system 300.

[0115] In the fourth embodiment, the first member node can be connected to the control node 100 among the multiple network nodes through the first relay node and operate as the second relay node. In other words, the first member node can operate as the child node of the first relay node and can also operate as the second relay node (i.e., the parent node) of other member nodes (such as the second member node among the multiple network nodes).

[0116] It should be understood that Figure 10 the first and second member nodes referred to in the following embodiments and Figures 1 to 9E the first and second member nodes mentioned in Figure 10 may have different concepts. For example,

[0117] In one embodiment, the first member node operating as the second relay node can be connected to the wireless terminal interface of the second member node through the access point interface of the first member node to operate as the second relay node of the second member node.

[0118] In addition, the first member node can also operate as a wireless terminal served by the first relay node. That is, the first member node can be connected to the access point interface of the first relay node through the wireless terminal interface of the first member node, and the first relay node can provide access point functions and operate as the access point of the first member node.

[0119] In the fourth embodiment, the first member node can determine whether the connection between the first relay node and the first member node is disconnected. In one embodiment, the first member node can determine whether the connection between its wireless terminal interface and the access point interface of the first relay node is disconnected. If so, the first member node can determine that the connection between the first relay node and the first member node has been disconnected. In addition, in one embodiment, if the first member node determines that there is a beacon miss between it and the first relay node, the first member node can determine that the connection between the first relay node and the first member node has been disconnected, but it is not limited thereto.

[0120] In Figure 10 step S1010, in response to determining that the connection between the first relay node and the first member node is disconnected, the first member node stops operating as the second relay node. In the fourth embodiment, the first member node can stop operating as the second relay node (for the second member node and / or other member nodes) by disabling the access point interface of the first member node.

[0121] From another perspective, when the first member node determines that the connection between it and the corresponding parent node is disconnected, it can immediately disable the access point function provided by the first member node, so that the first member node temporarily stops operating as the parent node / access point of other member nodes. In this case, the second member node that regards the first member node as the parent node will also determine that the connection between it and the first member node is disconnected, and thus also disable the access point function provided by the second member node. In other words, the second member node will also temporarily stop operating as the parent node / access point of other member nodes.

[0122] Based on this, it can be avoided that the child node misunderstands that the parent node can still normally provide the access point function, so that the child node can try to change to other member nodes that can normally provide the access point function as the (new) parent node. Thereby, the transmission ability of the child node can be maintained, and the transmission efficiency of the tree-shaped network topology can be better guaranteed.

[0123] To make the concept of the fourth embodiment easier to understand, the following is further described with Figures 11A to 11C for further illustration, where Figures 11A to 11C is an application scenario diagram shown according to the fourth embodiment of the present invention.

[0124] In Figure 11AIn this case, it is assumed that the control node 100 establishes a tree network topology 1110 through the mechanism of the previous embodiment, where member node 13 operates as a relay node for member node 14, member node 11 operates as a relay node for member node 13, and member node 12 is directly connected to the control node 100.

[0125] In the fourth embodiment, it will be assumed that member node 13 corresponds to Figure 10 the first member node mentioned, but this is only for illustration and not for limiting the possible embodiments of the present invention. In this case, member node 11 can be understood as Figure 10 the first relay node in, and member node 14 can be understood as the second member node served by member node 13, but it is not limited thereto.

[0126] In Figure 11A it is assumed that the distance between member node 13 and the control node 100 exceeds the connection distance threshold. In this case, member node 13 can be regarded as physically unable to be directly connected to the control node 100, so it must be connected to the control node 100 through other relay nodes. In addition, the distance between member node 14 and the control node 100 is also assumed to exceed the connection distance threshold, so member node 14 must also be connected to the control node 100 through other relay nodes.

[0127] In Figure 11B it is assumed that member node 11 fails to operate properly due to some reason (such as being unable to provide an access point function), then member node 13 can accordingly determine that the connection between member node 11 and member node 13 is disconnected according to the previous teachings. In this case, member node 13 can accordingly stop operating as a relay node for other member nodes (such as member node 14) (corresponding to step S1010). For example, member node 13 can stop providing the access point function by disabling its own access point interface, but it is not limited thereto.

[0128] Similarly, member node 14 can also accordingly determine that the connection between member node 14 and member node 13 is disconnected according to the previous teachings. In this case, member node 14 can also accordingly stop operating as a relay node for other member nodes. For example, member node 14 can also stop providing the access point function by disabling its own access point interface, but it is not limited thereto.

[0129] Next, member nodes 14 and 13 will attempt to find a new relay node. In Figure 11CIn this case, after obtaining the signal scanning result provided by member node 14, control node 100 can control member node 14 to connect to member node 12 according to the teachings of the previous embodiments (such as the second and / or third embodiments). In this situation, member node 14 can regard member node 12 as a relay node (i.e., a parent node), and can operate as a relay node for other member nodes again by enabling the access point interface of member node 14.

[0130] In Figure 11D this case, after obtaining the signal scanning result provided by member node 13, control node 100 can control member node 13 to connect to member node 14 according to the teachings of the previous embodiments (such as the second and / or third embodiments). In this situation, member node 13 can regard member node 14 as a relay node (i.e., a parent node), and can operate as a relay node for other member nodes again by enabling the access point interface of member node 13.

[0131] In one embodiment, if member node 13 fails to immediately stop operating as a relay node (e.g., disabling the access point interface) when determining that the connection between member node 11 and member node 13 is disconnected, it will cause the member nodes 14 served by member node 13 to be unable to immediately switch to other member nodes as relay nodes. In this case, member node 13 will also be unable to immediately switch to other member nodes as relay nodes accordingly. In other words, member nodes 13 and 14 will be continuously trapped in Figure 11B the situation shown.

[0132] When member nodes 13 and 14 are trapped in Figure 11B the situation shown, in addition to being unable to obtain relevant data of the mesh network through the relay node itself, member node 13 will also cause the member nodes 14 it serves to be unable to obtain relevant data of the mesh network. In this case, only when member node 11 resumes normal operation can member node 13 use member node 11 as a relay node again, and then operate normally in the Figure 11A architecture shown.

[0133] In addition, if member node 13 fails to immediately stop operating as a relay node (e.g., disabling the access point interface) when determining that the connection between member node 11 and member node 13 is disconnected, member node 13 may also switch to member node 14 as a relay node. In other words, member nodes 13 and 14 may be parent and child nodes of each other. In this case, member nodes 13 and 14 still cannot obtain relevant data of the mesh network and thus cannot operate normally.

[0134] However, through the Figures 11A to 11D mechanism shown, the above situations can be avoided, thus better maintaining the performance of the tree network topology 1110.

[0135] In summary, the technical solution of the embodiment of the present invention can update the tree-shaped network topology based on the signal scanning results of each network node after determining the initial tree-shaped network topology, so that each member node can be connected to the control node in a better manner. Thereby, better transmission quality and / or reliability can be achieved for each member node.

[0136] In addition, the embodiment of the present invention also proposes a technical solution that enables a member node to immediately stop operating as a relay node when it determines that the connection between it and the corresponding relay node is disconnected. Thereby, the member node and other member nodes originally served by it can immediately switch to other member nodes as relay nodes, thus avoiding the situation of being unable to obtain relevant data of the mesh network for a long time and achieving the effect of maintaining the performance of the tree-shaped network topology.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-hop wireless network system including multiple network nodes, characterized in that, it includes: A first member node, which is connected to a control node among the multiple network nodes through a first relay node in a tree topology network formed by the multiple network nodes and operates as a second relay node, wherein the first member node is configured to: In response to determining that the connection line between the first relay node and the first member node is disconnected, stop operating as the second relay node.

2. The multi-hop wireless network system according to claim 1, wherein the distance between the first member node and the control node exceeds a connection line distance threshold.

3. The multi-hop wireless network system according to claim 1, wherein the first member node is connected to a wireless terminal interface of a second member node through an access point interface of the first member node to operate as the second relay node of the second member node.

4. The multi-hop wireless network system according to claim 3, wherein the first member node stops operating as the second relay node by disabling the access point interface of the first member node.

5. The multi-hop wireless network system according to claim 4, wherein the first member node is further configured to: In response to determining that the first member node is switched by the control node to be connected to the control node through a third relay node, operate as the second relay node again by enabling the access point interface of the first member node.

6. The multi-hop wireless network system according to claim 1, wherein the first member node operates as a wireless terminal served by the first relay node.

7. The multi-hop wireless network system according to claim 6, wherein the first member node is connected to an access point interface of the first relay node through a wireless terminal interface of the first member node, and the first member node is configured to: In response to determining that the connection line between the wireless terminal interface of the first member node and the access point interface of the first relay node is disconnected, determine that the connection line between the first relay node and the first member node is disconnected.

8. The multi-hop wireless network system according to claim 1, further including: The control node, which is configured to: Obtain a signal scanning result of the first member node; and Based on the signal scanning result of the first member node, switch the first member node to be connected to the control node through a third relay node.

9. The multi-hop wireless network system according to claim 8, wherein the control node is a multi-point repeater and the first member node is a mesh access point.

10. A method for maintaining a tree network topology, characterized in that, The method is executed by a first member node among multiple network nodes of a multi-hop wireless network system, wherein the first member node is connected to a control node among the multiple network nodes through a first relay node in a tree topology network formed by the multiple network nodes and operates as a second relay node, and the method includes: In response to determining that the connection between the first relay node and the first member node is disconnected, the first member node stops operating as the second relay node.

11. A first member node, characterized in that the first member node is connected to a control node among the multiple network nodes through a first relay node in a tree topology network formed by the multiple network nodes, and operates as a second relay node, where the first member node is configured to perform: In response to determining that the connection between the first relay node and the first member node is disconnected, stop operating as the second relay node.

12. The first member node according to claim 11, wherein the distance between the first member node and the control node exceeds a connection distance threshold.

13. The first member node according to claim 11, wherein the first member node is connected to a wireless terminal interface of a second member node through an access point interface of the first member node to operate as the second relay node of the second member node.

14. The first member node according to claim 13, wherein the first member node stops operating as the second relay node by disabling the access point interface of the first member node.

15. The first member node according to claim 14, wherein the first member node is further configured to: In response to determining that the first member node is switched by the control node to be connected to the control node through a third relay node, operate as the second relay node again by enabling the access point interface of the first member node.

16. The first member node according to claim 11, wherein the first member node operates as a wireless terminal served by the first relay node.

17. The first member node according to claim 16, wherein the first member node is connected to an access point interface of the first relay node through a wireless terminal interface of the first member node, and the first member node is configured to: In response to determining that the connection between the wireless terminal interface of the first member node and the access point interface of the first relay node is disconnected, determine that the connection between the first relay node and the first member node is disconnected.

18. The first member node according to claim 11, wherein the control node is a multi-point repeater, and the first member node is a mesh access point.

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