Wi-SUN star networking leaf node direct connection communication method and system

Abstract

The present disclosure provides a Wi-SUN star networking leaf node direct connection communication method and system, a hybrid routing decision module is arranged in each leaf node, when a source leaf node needs to send data to a target leaf node, whether the direct connection condition is met is judged based on the local neighbor node table and the link quality; if the direct connection condition is met, a direct communication path with the target leaf node is established through a dynamically allocated special time slot; if the direct connection condition is not met, path information is requested from a center node, and a direct connection path through an intermediate node or a center node forwarding path is established according to the response. Through direct connection communication between leaf nodes, the communication efficiency between leaf nodes in Wi-SUN star networking is improved, and at the same time, the communication load of the center node is reduced.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of wireless communication network, in particular, to a Wi-SUN star networking leaf node direct connection communication method and system. BACKGROUND

[0002] The current Wi-SUN standard is based on IPv6 protocol and is widely used in smart grid, industrial Internet of Things and other scenarios. Its typical star topology relies on a single center node (such as a gateway router) as the relay node for all communications. Data transmission between leaf nodes needs to be forwarded by the center node in two hops, introducing an additional 10-100 ms level delay, which cannot meet the millisecond level real-time requirements of smart grid fault isolation, industrial control and other scenarios. Moreover, the data traffic of the whole network is concentrated in the center node, which is easy to cause congestion and packet loss in burst traffic scenarios (such as smart meter centralized reporting), thereby limiting the network scalability. SUMMARY

[0003] The embodiments of the present disclosure at least provide a Wi-SUN star networking leaf node direct connection communication method, which can improve the communication efficiency between leaf nodes in Wi-SUN star networking through direct connection communication between leaf nodes, and at the same time, reduce the communication load of the center node.

[0004] The embodiments of the present disclosure provide a Wi-SUN star networking leaf node direct connection communication method, which is provided with a hybrid routing decision module in each leaf node. The method comprises:

[0005] When the source leaf node needs to send data to the target leaf node, it judges whether the direct connection condition is met based on the local neighbor node table and the link quality;

[0006] If the direct connection condition is met, a direct communication path with the target leaf node is established through the dynamically allocated dedicated time slot;

[0007] If the direct connection condition is not met, the path information is requested from the center node, and a direct connection path through the intermediate node or a center node forwarding path is established according to the response.

[0008] In some embodiments, the hybrid routing decision module comprises a neighbor discovery unit, a routing decision unit and a time slot allocation unit.

[0009] In some embodiments, it further comprises:

[0010] Each leaf node broadcasts a discovery packet at a preset period; the discovery packet comprises the leaf node ID, the supported communication frequency band and the received signal strength;

[0011] When each leaf node receives the discovery packet, the local neighbor node table is updated according to the information in the discovery packet, and the link quality of the local neighbor node corresponding to the discovery packet is calculated according to the received signal strength in the discovery packet.

[0012] In some embodiments, when the source leaf node needs to send data to the target leaf node, the source leaf node determines whether the direct connection condition is met based on the local neighbor node table and the link quality, including:

[0013] When the data packet to be sent by the source leaf node to the target leaf node exceeds the preset data amount,

[0014] The source leaf node determines whether the link quality of the target leaf node is greater than a preset received signal strength threshold according to the local neighbor node table.

[0015] In some embodiments, the path information is requested from the center node, and a direct connection path through the intermediate node or a forwarding path through the center node is established according to the response, including:

[0016] The source leaf node sends a path request to the center node;

[0017] The source leaf node receives path information corresponding to the path request sent by the center node; the path information includes a data sending path of the source leaf node to the target leaf node determined by the center node according to a network topology information database; the network topology information database includes direct connection channel information and link quality information of each leaf node;

[0018] The source leaf node sends the data packet to the target leaf node according to the path information.

[0019] In some embodiments, the path information includes a multi-stage direct connection path of the source leaf node to the target leaf node through at least one intermediate node, or a forwarding path of the source leaf node to the target leaf node through the center node.

[0020] In some embodiments, the method further includes:

[0021] When the source leaf node sends the data packet to the target leaf node through the direct communication path, if the fallback condition is triggered, the source leaf node forwards the data packet to the target leaf node through the center node; the fallback condition includes three consecutive missing acknowledgement characters, a packet loss rate exceeding 10%, or three consecutive received signal strength fluctuation values greater than 3dB / s.

[0022] In some embodiments, the method further includes:

[0023] When the direct communication path is closed, the target leaf node sends the sequence number of the last received data packet to the center node;

[0024] The central node compares the data packets sent from the source leaf node to the target leaf node based on the sequence number;

[0025] If the sequence number does not match the last data packet sent by the source leaf node, the central node will send the missing data after the data packet corresponding to the sequence number to the target leaf node.

[0026] In some embodiments, it also includes:

[0027] When the central node fails, each leaf node actively establishes direct communication with its neighbor leaf nodes in the local neighbor node table.

[0028] This disclosure also provides a Wi-SUN communication system applicable to any of the above embodiments, including:

[0029] The central node is used to maintain the network topology database and respond to path requests;

[0030] Multiple leaf nodes, including a hybrid routing decision module, are used to perform neighbor discovery, dynamic time slot allocation, and dual-mode communication;

[0031] The Beacon frames sent by the leaf nodes contain the direct connectivity capability field.

[0032] To make the above-mentioned objects, features and advantages of this disclosure more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. These drawings are incorporated in and constitute a part of this specification. They illustrate embodiments conforming to this disclosure and, together with the specification, serve to explain the technical solutions of this disclosure. It should be understood that the following drawings only show some embodiments of this disclosure and should not be considered as limiting the scope. Those skilled in the art can obtain other related drawings based on these drawings without creative effort.

[0034] Figure 1 A schematic diagram of a direct communication method for leaf nodes in a Wi-SUN star network provided in an embodiment of this disclosure is shown.

[0035] Figure 2 A schematic diagram of an enhanced Beacon frame provided in an embodiment of this disclosure is shown. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. The components of the embodiments of this disclosure described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this disclosure provided in the accompanying drawings is not intended to limit the scope of the claimed disclosure, but merely represents selected embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0038] In this document, the term "and / or" merely describes a relationship, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0039] Based on the above research, this disclosure provides a direct communication method for leaf nodes in a Wi-SUN star network. This method utilizes direct communication paths established between leaf nodes to improve communication efficiency between leaf nodes in a Wi-SUN star network, while reducing the communication load on the central node.

[0040] like Figure 1 As shown, Figure 1 This is a schematic diagram of a direct communication method for leaf nodes in a Wi-SUN star network according to an embodiment of this disclosure. Each leaf node includes a hybrid routing decision module. The method includes:

[0041] S101. When the source leaf node needs to send data to the target leaf node, it determines whether the direct connection condition is met based on the local neighbor node table and the link quality.

[0042] S102. If the direct connection condition is met, a direct communication path with the target leaf node is established through a dynamically allocated dedicated time slot.

[0043] S103. If the direct connection condition is not met, request path information from the central node and establish a direct connection path through the intermediate node or a forwarding path through the central node based on the response.

[0044] Specifically, when a source leaf node needs to send data to other leaf nodes (i.e., the target leaf node), unlike the traditional method of forwarding through a central node, this embodiment of the disclosure determines whether the target leaf node is in the table by querying the local neighbor node table of the source leaf node. If it is in the table, it determines whether the direct connection condition is met based on the link quality of the target leaf node.

[0045] When the direct connection condition is met, a direct communication path with the target leaf node is established through a dynamically allocated dedicated time slot, and data is sent to the target leaf node through this direct communication path.

[0046] The dynamically allocated dedicated time slots are obtained through a dynamic time slot allocation algorithm. This algorithm is based on the TDMA (Time Division Multiple Access) mechanism and allocates time slots for direct communication between two leaf nodes in a Wi-SUN star network. The algorithm first uses the current superframe number of the central coordinator as a base, multiplying it by the number of time slots contained in each frame to obtain a basic time slot value, ensuring that the time slot allocation is associated with the current superframe. Then, it performs an XOR operation on the device identifiers of the two leaf nodes, takes the result modulo the maximum number of directly connected time slots to obtain an offset within the valid range, and adds it to the basic time slot value to obtain the initial value of the directly connected time slot. Finally, it performs a bitwise OR operation (0x8000) on the initial directly connected time slot value, setting the highest bit of the time slot to 1, thus specifically marking this time slot as a time slot for direct communication between leaf nodes, distinguishing it from time slots for communication between nodes and the coordinator.

[0047] When the direct connection condition is not met, the source leaf node requests path information from the central node. The central node evaluates the communication path between the source leaf node and the target leaf node and determines the preferred path. This preferred path may be to achieve a fast data transmission channel by using at least one leaf node between the source leaf node and the target leaf node as a relay for multiple direct communication segments, or it may be a traditional forwarding path by using the central node for data forwarding.

[0048] In some embodiments, the hybrid routing decision module includes a neighbor discovery unit, a routing decision unit, and a time slot allocation unit.

[0049] Specifically, the hybrid routing decision module carries a dynamic time slot allocation algorithm for dynamically allocating dedicated time slots. This algorithm is based on TDMA (Time Division Multiple Access) mechanism to allocate time slots for direct communication between two leaf nodes in a Wi-SUN star network. The algorithm first uses the current superframe number of the central coordinator as a base, multiplying it by the number of time slots contained in each frame to obtain a basic time slot value, ensuring that the time slot allocation is associated with the current superframe (corresponding to the neighbor discovery unit). Then, it performs an XOR operation on the device identifiers of the two leaf nodes, takes the result modulo the maximum number of directly connected time slots to obtain an offset within the valid range, and adds it to the basic time slot value to obtain the initial value of the directly connected time slot (corresponding to the routing decision unit). Finally, it performs a bitwise OR operation (0x8000) on the initial directly connected time slot value, setting the highest bit of the time slot to 1, thus specifically marking this time slot as a time slot for direct communication between leaf nodes, distinguishing it from time slots for communication between nodes and the coordinator (corresponding to the time slot allocation unit).

[0050] In some embodiments, it also includes:

[0051] Each leaf node broadcasts a discovery message at a preset period; the discovery message includes the leaf node ID, supported communication frequency bands, and received signal strength.

[0052] When each leaf node receives a discovery message, it updates its local neighbor node table based on the information in the discovery message, and calculates the link quality of the local neighbor node corresponding to the discovery message based on the received signal strength in the discovery message.

[0053] Specifically, the local neighbor node table provided in this disclosure embodiment is as follows:

[0054]

[0055] The table records the neighbor node addresses, the average of the most recent N RSSI (Received Signal Strength Indication), the link quality index based on PER (Packet Error Rate), and the clock synchronization error.

[0056] In some embodiments, when a source leaf node needs to send data to a target leaf node, it determines whether the direct connection condition is met based on its local neighbor node table and link quality, including:

[0057] When the data packets that the source leaf node needs to send to the target leaf node exceed the preset data size...

[0058] The source leaf node determines whether the link quality of the target leaf node is greater than a preset received signal strength threshold based on its local neighbor node table.

[0059] Specifically, this disclosure presents a hybrid routing decision model for selecting which path to use for data transmission. First, it needs to determine whether a direct connection condition is met. The direct connection conditions that must be met simultaneously are as follows:

[0060] 1. Data packet size > preset data volume;

[0061] 2. Link quality > preset received signal strength threshold.

[0062] When the above two direct connection conditions are met, the direct communication mode is enabled, and the source leaf node communicates data through the direct communication path. In specific scenarios with extremely high real-time requirements (such as low-latency control commands, emergency collaboration between nodes, etc.), leaf nodes are allowed to proactively initiate direct communication requests and enable direct communication mode directly without judging the data packet size, in order to meet the priority requirements of specific services.

[0063] In some embodiments, requesting path information from the central node and establishing a direct path via intermediate nodes or a forwarding path via the central node based on the response includes:

[0064] The source leaf node sends a path request to the central node;

[0065] The source leaf node receives path information corresponding to the path request sent by the central node; the path information includes the data transmission path from the source leaf node to the target leaf node determined by the central node according to the network topology information database; the network topology information database includes the direct connection channel information and link quality information of each leaf node;

[0066] The source leaf node sends the data packet to the target leaf node based on the path information.

[0067] In some embodiments, the path information includes a multi-level direct path from the source leaf node to the target leaf node through at least one intermediate node, or a forwarding path from the source leaf node to the target leaf node through a central node.

[0068] Specifically, when the direct connection condition is not met, first determine whether the load of the central node can carry the data packets to be sent by the source leaf node. If it can, the central node forwarding path can be selected; otherwise, the multi-level direct connection path through intermediate nodes is selected.

[0069] In some embodiments, it also includes:

[0070] When a source leaf node sends a data packet to a target leaf node through a direct communication path, if a fallback condition is triggered, the source leaf node forwards the data packet to the target leaf node through the central node. Fallback conditions include three consecutive lost acknowledgment characters, a packet loss rate exceeding 10%, or three consecutive received signal strength fluctuations exceeding 3dB / s.

[0071] Specifically, this embodiment also discloses a fallback mechanism. When the source leaf node sends data packets to the target leaf node through a direct communication path and experiences three consecutive lost acknowledgment characters, a packet loss rate exceeding 10%, or three consecutive received signal strength fluctuations exceeding 3dB / s, the fallback mechanism is triggered. The source leaf node sends a reason code to the central node. After receiving the reason code, the central node broadcasts a route update command to update the local neighbor node tables of the source leaf node and the target leaf node. The source leaf node converts the current data communication path to the target leaf node into a forwarding path via the central node.

[0072] In some embodiments, when the direct communication path is closed, the target leaf node sends the sequence number of the last received data packet to the central node;

[0073] The central node compares the data packets sent from the source leaf node to the target leaf node based on the sequence number;

[0074] If the sequence number does not match the last data packet sent by the source leaf node, the central node will send the missing data after the data packet corresponding to the sequence number to the target leaf node.

[0075] In some embodiments, it also includes:

[0076] When the central node fails, each leaf node actively establishes direct communication with its neighbor leaf nodes in the local neighbor node table.

[0077] Specifically, when a power grid failure causes the central node to fail, in order to maintain the operation of the Wi-SUN star network as much as possible, each leaf node actively enables direct communication mode. Data packets that cannot be directly transmitted or forwarded by neighboring nodes are recorded in the fault buffer and queued for forwarding when the central node resumes operation.

[0078] The direct communication method for leaf nodes in a Wi-SUN star network provided in this application improves the communication efficiency between leaf nodes in a Wi-SUN star network by enabling direct communication between leaf nodes, while reducing the communication load on the central node.

[0079] This disclosure also provides a Wi-SUN star network leaf node direct connection communication system, applicable to any of the above embodiments, including:

[0080] The central node is used to maintain the network topology database and respond to path requests;

[0081] Multiple leaf nodes, including a hybrid routing decision module, are used to perform neighbor discovery, dynamic time slot allocation, and dual-mode communication;

[0082] The Beacon frames sent by the leaf nodes contain the direct connectivity capability field.

[0083] As shown in Figure 2, Figure 2 An enhanced Beacon frame is provided in this embodiment of the present disclosure. The enhanced Beacon adds 0x40 to the frame control field (frame_ctrl) to indicate support for direct connection, and adds a direct connection capability field (DCB_field), in which bits 0-3 are used to indicate available channels and bits 4-7 are used to indicate maximum transmit power.

[0084] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems and devices described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. In the several embodiments provided in this disclosure, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division; in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the displayed or discussed mutual coupling or direct coupling or communication connection may be through some communication interfaces; the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms.

[0085] 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 units can be selected to achieve the purpose of this embodiment according to actual needs.

[0086] Finally, it should be noted that the above-described embodiments are merely specific implementations of this disclosure, used to illustrate the technical solutions of this disclosure, and not to limit it. The protection scope of this disclosure is not limited thereto. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this disclosure. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure, and should all be covered within the protection scope of this disclosure. Therefore, the protection scope of this disclosure should be determined by the protection scope of the claims.

Claims

1. A method for direct communication between leaf nodes in a Wi-SUN star network, characterized in that, Each leaf node contains a hybrid routing decision module, and the method includes: When a source leaf node needs to send data to a target leaf node, it determines whether the direct connection condition is met based on its local neighbor node table and link quality. If the direct connection condition is met, a direct communication path with the target leaf node is established through a dynamically allocated dedicated time slot; If the direct connection conditions are not met, request path information from the central node, and establish a direct connection path through intermediate nodes or a forwarding path through the central node based on the response. When the source leaf node needs to send data to the target leaf node, it determines whether the direct connection condition is met based on its local neighbor node table and link quality, including: When the data packets that the source leaf node needs to send to the target leaf node exceed the preset data amount, the source leaf node determines whether the link quality of the target leaf node is greater than the preset received signal strength threshold based on the local neighbor node table.

2. The method as described in claim 1, characterized in that, The hybrid routing decision module includes a neighbor discovery unit, a routing decision unit, and a time slot allocation unit.

3. The method as described in claim 1, characterized in that, Also includes: Each leaf node broadcasts a discovery message at a preset period; the discovery message includes the leaf node ID, supported communication frequency bands, and received signal strength. When each leaf node receives a discovery message, it updates its local neighbor node table based on the information in the discovery message, and calculates the link quality of the local neighbor node corresponding to the discovery message based on the received signal strength in the discovery message.

4. The method as described in claim 1, characterized in that, Request path information from the central node, and establish a direct path via intermediate nodes or a forwarding path via the central node based on the response, including: The source leaf node sends a path request to the central node; The source leaf node receives path information corresponding to the path request sent by the central node; the path information includes the data transmission path from the source leaf node to the target leaf node determined by the central node according to the network topology information database; the network topology information database includes direct connection channel information and link quality information of each leaf node. The source leaf node sends the data packet to the target leaf node according to the path information.

5. The method as described in claim 4, characterized in that, The path information includes a multi-level direct path from the source leaf node to the target leaf node through at least one intermediate node, or a forwarding path from the source leaf node to the target leaf node through a central node.

6. The method as described in claim 1, characterized in that, Also includes: When the source leaf node sends a data packet to the target leaf node through the direct communication path, if a fallback condition is triggered, the source leaf node forwards the data packet to the target leaf node through the central node. The fallback condition includes three consecutive lost acknowledgment characters, a packet loss rate exceeding 10%, or three consecutive received signal strength fluctuations exceeding 3dB / s.

7. The method as described in claim 1, characterized in that, The method further includes: When the direct communication path is closed, the target leaf node sends the sequence number of the last received data packet to the central node; The central node compares the data packets sent from the source leaf node to the target leaf node according to the sequence number; If the sequence number does not match the last data packet sent by the source leaf node, the central node will send the missing data after the data packet corresponding to the sequence number to the target leaf node.

8. The method as described in claim 1, characterized in that, Also includes: When the central node fails, each leaf node actively establishes direct communication with its neighboring leaf nodes in the local neighbor node table.

9. A Wi-SUN star-topology leaf node direct-connection communication system, applicable to the method described in any one of claims 1-8, characterized in that, include: The central node is used to maintain the network topology database and respond to path requests; Multiple leaf nodes, including a hybrid routing decision module, are used to perform neighbor discovery, dynamic time slot allocation, and dual-mode communication; The Beacon frames sent by the leaf nodes contain a direct connectivity capability field.

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