CN111542030A

CN111542030A - Optimal TTL value calculation method of Bluetooth Mesh, system thereof and computer readable storage medium

Info

Publication number: CN111542030A
Application number: CN202010320560.0A
Authority: CN
Inventors: 陈柏康
Original assignee: Shenzhen Zhongke Lanxun Technology Co ltd
Current assignee: Shenzhen Zhongke Lanxun Technology Co ltd
Priority date: 2020-04-21
Filing date: 2020-04-21
Publication date: 2020-08-14

Abstract

The invention provides a method for calculating an optimal TTL value of a Bluetooth Mesh, which comprises the following steps: a node binding step, wherein each node of the Bluetooth Mesh scans surrounding nodes through searching and establishes BLE connection with the surrounding nodes; a link counting step, wherein each node of the Mesh network respectively counts link information of a local node and other nodes; and a TTL calculation step, namely calculating the optimal TTL value according to the target address and the link information of the message. The invention counts the link of the message relay path through the layer-by-layer binding relationship between the binding nodes, and obtains the optimal relay path and the optimal TTL value by combining DST.

Description

Optimal TTL value calculation method of Bluetooth Mesh, system thereof and computer readable storage medium

Technical Field

The invention relates to the field of Bluetooth Mesh, in particular to a method and a system for calculating an optimal TTL value of Bluetooth Mesh and a computer readable storage medium.

Background

The Bluetooth Mesh is a many-to-many network based on Bluetooth Low Energy (BLE), and BLE devices in the network are called nodes, that is, nodes, each Node can freely communicate with other nodes, and the types of the nodes are divided according to their characteristics:

an LP Node (low power Node), a Node with limited power, saves power consumption by using low power consumption characteristics;

friend Node, cooperate with LP Node, store message and security updating sent to LP Node, transmit the information stored to LP Node again when LP Node needs;

the Relay Node can receive and forward messages, and realizes a larger-scale network through the Relay of the messages among the nodes;

and the Proxy Node realizes the transmission and reception of the mesh message between the GATT (Generic Attribute) and the Bluetooth mesh Node.

Due to the existence of the Relay Node, the Node can Relay data to other nodes which are not in the wireless coverage range of the initial Node, so that the mesh network can span a very large physical area and contain a large number of BLE devices.

In the network data communication process of the method, the nodes transmit the received data through broadcasting, and when the distance between the two nodes is long, the intermediate node needs to continuously broadcast the first-level broadcast data and finally can reach the destination node. Because it is unknown that the target node needs several relays, when the distance between the nodes is short and the set TTL is large, unnecessary repeated relays are caused, the processing amount of the nodes is increased, useless messages are distributed in the network, and new messages can not be received.

Disclosure of Invention

In view of the above problems, the present invention provides a method for calculating an optimal TTL value of a bluetooth Mesh, a system thereof, and a computer-readable storage medium, and aims to solve the data problem of the flooding method.

In a first aspect, the present invention provides a method for calculating an optimal TTL value of a bluetooth Mesh, including:

a node binding step, wherein each node of the Bluetooth Mesh scans surrounding nodes through searching and establishes BLE connection with the surrounding nodes;

a link counting step, wherein each node of the Mesh network respectively counts link information of a local node and other nodes;

and a TTL calculation step, namely calculating an optimal TTL value according to the target address of the message and the link information of the node.

Specifically, the node binding step includes establishing a local node list, exchanging node information between the bound nodes, and writing the node information into the local node list.

Specifically, the node binding method further includes: and deleting the nodes, namely deleting the node information of the disconnected nodes from a local node list of the connected nodes after the nodes are disconnected.

Specifically, in the link statistics step, each node of the Mesh network respectively counts link information of the local node and other nodes, specifically, a node link list is established, link information of the local node and other nodes is counted, and the link information is written into the node link list.

Specifically, the counting of the link information between the local node and the other nodes is to count the receiving and sending of the directional broadcast packet between the binding nodes.

Specifically, the link information includes DST, SRC, link node number, and link node address.

Specifically, the link statistics step further includes: and deleting the node link, and deleting the node link of the disconnected node from the node link list of other nodes after the disconnection between the nodes.

Specifically, the link counting step further includes that a node link is newly added, and when a new node is accessed to the Mesh network, each node of the Mesh network executes the link counting step again.

In a second aspect, the present invention provides a bluetooth Mesh system, which adopts the above method.

In a third aspect, the invention provides a non-transitory computer readable storage medium for storing computer instructions for causing a computer to perform the above method.

According to the method and the system for calculating the optimal TTL value of the Bluetooth Mesh and the computer readable storage medium, BLE connection is established between the node and surrounding nodes in the wireless coverage range of the node in the Mesh network to form a binding node, then links of a message relay path are counted through layer-by-layer binding relations among a plurality of binding nodes, and the optimal relay path and the optimal TTL value are obtained by combining DST.

And the BLE connection is adopted between the binding nodes, compared with broadcasting, the BLE connection has faster timeliness and reliability, whether the binding nodes are still in the binding range can be known more quickly, and the timeliness and the reliability of message transmission are ensured.

Drawings

Fig. 1 is a schematic diagram of a data format of a networking broadcast packet provided by the present invention.

Fig. 2A is a schematic diagram of an Opcode packet format used in the node information exchange provided by the present invention.

Fig. 2B is a schematic diagram of an Opcode command packet format used in the node information exchange provided by the present invention.

Fig. 3 is a schematic diagram of corresponding parameters of a local node list of a node provided by the present invention.

Fig. 4A, 4B, and 4C are schematic diagrams illustrating the position changes of the node N4 and the binding nodes N1, N2, and N3 provided by the present invention, respectively.

Fig. 5 is a schematic diagram of corresponding parameters of a node link list of a node provided by the present invention.

Fig. 6 is a schematic diagram of a relay path with a source address of node N1 and a destination address of N4 according to the present invention.

Fig. 7 is a schematic diagram of a packet transmission path of a Mesh network according to the present invention.

Fig. 8 is a schematic diagram of a packet transmission path when the node N7 is disconnected according to the present invention.

Fig. 9 is a flowchart of a method for calculating an optimal TTL value according to the present invention.

Detailed Description

The technical solutions in the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the present invention, and not all of it. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step, are within the scope of the present invention.

The invention provides a method for calculating an optimal TTL value of a Bluetooth Mesh, which comprises the following steps:

And (3) node binding process:

when the node is accessed to the Mesh network, the networking device scans surrounding BLE equipment, when a Mesh broadcast packet is scanned, the Mesh network can be accessed to become a node in the Mesh network after being configured by the networking device, the networking device sends a network key and allocates a unicast address to the node through the networking broadcast packet, wherein the NID generated by the network key is used for representing a corresponding subnet (subnet), and the unicast address is an identity of the node.

The networking broadcast packet is sent by using Advertising Data, and referring to fig. 1, a Data format of the networking broadcast packet is shown, where Payload for loading broadcast content includes AdvA and AdvData, AdvA is an allocated unicast address, AdvData is broadcast Data, AD Structure included in the packet includes AD _ Length, AD _ Type, and AD _ Data, AD _ Length is a Length of the AD Type and AD _ Data, AD _ Type is an AD Type corresponding to PB-ADV, and AD _ Data is PB-ADVPDU.

After the nodes complete networking, a node binding step is further executed, in the step, the nodes search and scan surrounding nodes in the wireless coverage range of the nodes in the Mesh network, BLE connection is established with the nodes one by one, one node connected with the BLE and the surrounding nodes are collectively called as a binding node in the invention, and under the condition that the transmitting power is unchanged, the binding node can be successfully bound and is not disconnected, the data packet of the binding node in the binding process can be normally received and sent, so that the broadcast packet of the node can be received by other nodes of the binding node.

The above-mentioned node binding step further includes establishing a local node list, exchanging node information between the binding nodes, and writing the node information into the local node list. The node information includes a bluetooth address of the node, a NID, and a unicast address corresponding to the NID. In the Mesh network, it may include multiple subnets, and the same node may be in different subnets at the same time, so the node information of the node may include the same unicast address under different subnets, that is, in the local node list, the same node may have the same unicast address corresponding to different NIDs. When the node information between the binding nodes is exchanged, only the node information under the same network is exchanged, and the node information under different networks is not processed.

As an optional example of the above node information exchange, the exchange of the node information between the binding nodes is implemented by an Opcode packet, and referring to fig. 2A, a format of the Opcode packet is shown, the Opcode packet is a general Opcode packet specified by the bluetooth Mesh protocol specification, an LLID shown in the figure represents a type of the packet, in this example, the LLID is 01 and represents a data packet, and Ctrdata shown in the figure is a unicast address of the node information.

As another alternative example of the above node information exchange, the exchange of the node information between the binding nodes is implemented by an Opcode command packet, and referring to fig. 2B, a format of the Opcode packet is shown, the Opcode packet is a general Opcode packet specified by the bluetooth Mesh protocol specification, an LLID shown in the figure represents a type of the packet, in this example, the LLID is 11 and represents a command packet, and an ATT _ Parameter shown in the figure is a unicast address of the node information.

As another optional example of the above node information exchange, the exchange of the node information between the binding nodes is implemented by a custom Profile, and the exchange of the node information is completed by polling of the binding nodes in the networking process.

The local node list may include a plurality of parameters as needed, and as an example of the present invention, referring to fig. 3, the local node list includes a bluetooth address corresponding to a node, a NID, and a unicast address corresponding to the NID, corresponding to node information.

The node binding further includes: and deleting the nodes, namely deleting the node information of the disconnected nodes from a local node list of the connected nodes after the BLE connection between the nodes is disconnected.

In a bluetooth Mesh network, the positions of all nodes are not all fixed, and there is a possibility that some nodes are movable. In the Bluetooth Mesh network, when a certain node in the binding nodes moves to disconnect the node from one or more of other binding nodes, the node information of the node is deleted from the local node list of the disconnected binding node, and the other binding nodes which are continuously connected with the node are kept unchanged.

Referring to fig. 4A, 4B, and 4C, referring to fig. 4A, among the binding nodes N1, N2, N3, and N4, node N4 is a movable node, when node N4 moves to the position shown in fig. 4B for some reason, node N4 disconnects from node N1, node N1 deletes node information about node N4 from its local node list after finding that node N4 disconnects, while node N4 continues to remain connected to node N3, and the local node list of node N3 does not change. When node N4 moves to the position shown in FIG. 4C, node N4 disconnects from node N3, and node N3 takes the same action, removing node information about node N4 from its local node list.

And (3) link statistics process:

in the Mesh Network, the relay of the Message is realized by the relay node, when the relay node receives the Message, whether the NID is matched or not is judged, after the NID is matched, the verification and judgment are carried out on the NetMIC (Message Integrity Check for Network), SRC (Source Address), DST (Destination Address), whether the Message is received or not is searched in the cache, after the conditions are met, whether the Message needs to be forwarded or not is judged according to the TTL value and the DST, when the TTL is more than or equal to 2 and the Destination Address is not the unicast Address of the node, the TTL value of the Message is reduced and forwarded together, and when the TTL is more than 1 or the Destination Address is the unicast Address of the node, the Message is not forwarded.

The TTL value is the survival time of the message in the Mesh network, and is specifically expressed as the number of times of relaying the message. The message is forwarded in the Mesh network in an unoriented manner, in order to ensure that the message can be smoothly forwarded to a target node, the initial value of the TTL value is generally set to be larger, so that the TTL value has enough relay times, and in order to ensure that the message is not forwarded too much in the network, so that a large amount of air redundant flow is caused, network resources are occupied, and the network throughput is affected, therefore, the TTL value needs to be appropriately limited.

Based on this, the method of the present invention obtains the optimal relay path through the link statistics step, in which each node of the Mesh network respectively counts link information of the local node and other nodes, specifically, establishes a node link list, counts link information of the local node and other nodes, and writes the link information into the node link list.

The node link list is shown in fig. 5, where the link information includes the number of link nodes, the link node addresses, SRC, and DST, where the number of link nodes is equal to the number of nodes passed through in the link, and the link node addresses include multiple link node addresses, which are the node addresses passed through by the link corresponding to the number of link nodes, and the link node addresses of the node link list are sequentially arranged in the relay path direction of the message.

As an example of the above link, referring to fig. 6, it shows a relay path routing graph with SRC N1 and DST N4 among Mesh network nodes N1, N2, N3, N4, N5, N6, N7, where a message is sent from node N1, and in the first path, forwarded via nodes N2, N3, and relayed to node N4; in the second path, the data is forwarded by the nodes N2, N3 and N5 and relayed to the node N4; in the third path, the data is forwarded by the nodes N2, N3, N5 and N6 and relayed to the node N4; in the fourth path, the packet is forwarded via nodes N2, N3, N5, N6, and N7, and relayed to node N4. Referring to fig. 5, in the node link list of node N1, links with SRC of 0X01 (i.e., the unicast address of node N1) and DST of 0X04 (i.e., the unicast address of node N4) include 4 links, which are link 1, link 2, link 3, and link 4, respectively.

In the above example, in addition to the node N4 representing the link 1, the link 2, the link 3, and the link 4 of the relay path, the node link list of the node N1 further includes the links of other nodes N2, N3, N5, N6, and N7, for example, the relay path of the node N2 with DST 0X02 is the link 5 shown in fig. 5, and the relay path of the node N3 with DST 0X03 is the link 6 shown in fig. 5.

When the message is sent from the source address, the optimal relay path for message transmission can be determined through the node link list, redundant relay times can be reduced, air redundant flow of the Mesh network is further reduced, and node caching and processing capacity are also reduced.

The above-mentioned statistics of the link information between the local node and other nodes is specifically performed by receiving and transmitting directional broadcast packets between the binding nodes. As described above, the binding nodes are connected through BLE, and the binding relationship is transmitted layer by layer through a plurality of different binding nodes in a data packet manner, and finally collected to the local node for statistics. Referring to fig. 7, shown therein:

n2 and the local node N1 are binding nodes;

n1, N3 and the local node N2 are binding nodes;

n2, N4, N5 and the local node N3 are binding nodes;

n3, N5, N6, N7 and the local node N4 are binding nodes with each other;

n3, N4, N6 and the local node N5 are binding nodes;

n4, N5, N7 and the local node N6 are binding nodes;

n4, N6 and the local node N7 are binding nodes.

The nodes N1, N2, N3, N4, N5, N6 and N7 form layer-by-layer binding of different binding nodes.

When the nodes in the Mesh network count the link information of the local node and other nodes, the transmission direction of the data packet is as the path shown in fig. 7, and the data packet is transmitted layer by layer through a plurality of different binding nodes and collected to the local node for counting. As an example, when the DST is counted as the link of the node N4, the node N1 sends a data packet through BLE connection in the Mesh network, the data packet is forwarded through the nodes N2 and N3 and reaches the node N4, the node N4 sends a response packet, the response packet is transmitted through a reverse path of the first path, the second path, the third path, and the fourth path shown in fig. 6 and reaches the node N1, and the link 1, the link 2, the link 3, and the link 4 of the node link list shown in fig. 5 are obtained.

Further, the link statistics step further includes: and deleting the node link, and deleting the node link of the disconnected node from the node link list of other nodes after the disconnection between the nodes.

When the nodes are disconnected, other binding nodes connected with the disconnected nodes send data packets through BLE to indicate other nodes in the Mesh network, the nodes are withdrawn from the Mesh network, and the other nodes, namely link node addresses in a local node link list and links of which DST contain unicast addresses of the disconnected nodes. For example, as shown in fig. 8, when node N7 disconnects BLE, nodes N4 and N6 detect that N7 is disconnected, send a packet through BLE in the Mesh network, notify nodes N1, N2, N3, and N5 of the disconnection of node N7, and all nodes N1, N2, N3, N4, N5, and N6 delete a link whose list link node address and DST contain the disconnected node unicast address from the local node link list, such as node N1 in fig. 5, link 4 containing node N7 unicast address 0X07 is deleted.

Further, the link counting step further comprises the step of adding a node link, and when a new node is accessed into the Mesh network, each node of the Mesh network executes the link counting step again.

When a new node is added into the Mesh network, each link of the Mesh network may be changed drastically, so that it is necessary to perform the link counting step again when the new node is added.

The node data packet in the Mesh network is transmitted through BLE, and compared with broadcasting, the Mesh network has higher timeliness and reliability.

In summary, the flow of the optimal TTL value calculation method is as shown in fig. 9, after the node binding step and the link counting step are performed, when each node in the Mesh network sends a message, a link of an optimal relay path is screened from a local node link list, an optimal path for forwarding the message is determined, and a TTL value in the optimal path of the message is determined according to the number of link nodes of the link, where the TTL value is the optimal TTL value. For example, in the path whose DST is the node N4 shown in fig. 6, the optimal relay path is the first path, that is, the link 1 shown in fig. 5, and the number of link nodes is 2, then the node N1 has an optimal TTL value of 2+1 — 3 when forwarding the message.

Based on the content, the invention also provides a Bluetooth Mesh system which adopts the method.

Based on the above, the present invention also provides a non-transitory computer-readable storage medium storing computer instructions for causing the computer to perform the above method. The related description can be understood according to the related description and effects of the above contents, and will not be described in detail herein.

In the present invention, a computer readable medium may be a tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a computer-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

While there have been shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices and methods described may be made by those skilled in the art without departing from the spirit of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for calculating the optimal TTL value of Bluetooth Mesh comprises the following steps:

2. The method of claim 1, wherein the node binding step comprises establishing a local node list, exchanging node information between the binding nodes, and writing the node information into the local node list.

3. The method of claim 1, the node binding method further comprising: and deleting the nodes, namely deleting the node information of the disconnected nodes from a local node list of the connected nodes after the nodes are disconnected.

4. The method according to any one of claims 1 to 3, wherein in the link statistics step, each node of the Mesh network respectively counts link information of the local node and other nodes, specifically, a node link list is established, link information of the local node and other nodes is counted, and the link information is written into the node link list.

5. The method as claimed in claim 4, wherein the counting the link information between the local node and other nodes is performed by transmitting and receiving directional broadcast packets between the binding nodes.

6. The method of claim 4, the link information comprising DST, SRC, number of link nodes, and link node address.

7. The method of claim 4, the link statistics step further comprising: and deleting the node link, and deleting the node link of the disconnected node from the node link list of other nodes after the disconnection between the nodes.

8. The method as claimed in claim 4, wherein the link counting step further comprises the step of adding a new node link, and each node of the Mesh network performs the link counting step again when a new node is accessed into the Mesh network.

9. A bluetooth Mesh system employing the method of any one of claims 1 to 8.

10. A non-transitory computer readable storage medium for storing computer instructions for causing a computer to perform the method of any one of claims 1-8.