A node combined routing method based on BLE Mesh network

Abstract

The present invention belongs to the field of communication technology, and specifically relates to a node combination routing method based on a BLE Mesh network, including: dividing BLE Mesh network nodes into a node combination topology structure through neighbor node information exchange, node role configuration and node combination full connectivity; when a source node has a need to transmit a data packet to a destination node, the shortest path among all transmission paths is obtained through routing detection and routing reply, and the data packet sent by the source node is transmitted to the destination node in sequence along the shortest path. The present invention limits the forwarding of ordinary nodes through a designed routing protocol, only allows leading nodes and relay nodes to forward data packets, and reduces the number of forwarding nodes, so as to achieve the purpose of suppressing redundant data packets, thereby reducing network energy consumption.

Description

Technical Field

[0001] The present invention belongs to the field of communication technologies, and particularly relates to a node combination routing method based on a BLE Mesh network. Background Art

[0002] In November 2017, after the Bluetooth Special Interest Group (SIG) published the BLE Mesh standard V1.0, BLE Mesh achieved a multi-to-multi communication method and quickly became a research hotspot in the Internet of Things field with the advantages of low power consumption and low cost, and is expected to play an important role in the Internet of Things. However, currently, BLE Mesh V1.0 only considers the management flooding protocol for network information transmission. When the network scale or the amount of transmitted data increases, a large number of redundant data packets will flood the network, resulting in increased unnecessary power consumption and wasting a large amount of network resources.

[0003] Regarding the problem of excessive energy consumption of management flooding, some scholars have conducted research without changing the flooding mechanism. The applicability of different relay selection algorithms based on Connected Dominating Set (CDS) has been evaluated and compared, and it has been proved that selecting appropriate relay nodes helps to alleviate the defects of the BLE Mesh management flooding mechanism. The balanced flooding transmission protocol increases the network lifetime by reducing the relay time. The enhanced flooding protocol reduces the network power consumption by adjusting the transmission power of the relay. However, due to the problems existing in the flooding mechanism itself, even if the number of relay nodes, relay time, or relay transmission power is reduced, a large number of redundant data packets still exist in the network, resulting in unnecessary power consumption. The asynchronous dynamic scanning mechanism reduces the scanning period of nodes and thus reduces the network power consumption by sending a new control message sequence before transmitting data while ensuring reliability. However, only a small network scenario with 4 nodes is considered, and this method is not applicable to the situation where there are a large number of nodes in the network. Some scholars have also given solutions for routing modes. The cluster-based on-demand routing protocol reduces the number of routing request messages in the routing discovery process by establishing clusters in the network and using the on-demand routing method, thereby reducing energy consumption. However, when selecting relay nodes for establishing clusters, only the relay nodes are selected from the candidate relay node set according to the size of the node numbers, and the distance factor between nodes is not considered.

[0004] In summary, the problems of the prior art are: the existing BLE Mesh only considers data transmission using the management flooding protocol; when the network scale or the amount of transmitted data increases, a large amount of redundant data will flood the network, resulting in increased energy consumption. Summary of the Invention

[0005] To solve the above technical problems, the present invention proposes a node combination routing method based on a BLE Mesh network, including:

[0006] S1: Node combination topology establishment: Divide the BLE Mesh network nodes into a node combination topology structure through neighbor node information exchange, node role configuration, and full connectivity of node combinations;

[0007] Neighbor node information exchange:

[0008] Select any reserved bit beacon on the reserved bits of the beacon type 0x02 - 0xFF as the neighbor node information exchange beacon, use the non - directional non - connectable broadcast packet of the Mesh Beacon type as the carrier of the beacon message of the neighbor node. During the neighbor node information exchange process, the BLE nodes exchange the broadcast packets of one - hop neighbor nodes, and the BLE nodes update the information unit according to the ID and neighbor number information of the adjacent nodes in the broadcast packet;

[0009] Node role configuration, including:

[0010] Select the BLE node with the largest neighbor number count as the leader node according to the updated information unit of all BLE nodes. When there is a situation where the neighbor number counts are the same, select the BLE node with the shortest total distance to all neighbor nodes as the leader node, and update its role to leader, and the remaining BLE nodes as ordinary nodes, and update their roles to ordinary;

[0011] Full connectivity of node combinations, including:

[0012] The leader node searches for adjacent nodes. Within the wireless communication range of the leader node, add the nodes that do not belong to this combination to the candidate node set composed of relay nodes; when the leader node finds multiple candidate relay nodes in the same adjacent node combination, select the node with the smallest average distance to the leader nodes in the two node combinations in the candidate node set to be upgraded to a relay node; the upgraded relay node updates its own role to relay, and uses the ID of this leader node as the ID of the second node combination to which it belongs;

[0013] S2: Routing establishment: When the source node has a need to transmit data packets to the destination node, obtain the shortest path among all transmission paths through route detection and route reply, and the data packets sent by the source node are transmitted to the destination node along the shortest path.

[0014] Preferably, the broadcast packet for neighbor node information exchange includes:

[0015] The carrier is a non - directional and non - connectable broadcast packet, including: according to each node only needing to collect the IDs and the number of neighbors of its neighbor nodes, the data part of the broadcast packet only contains two fields, namely the ID of the neighbor node and the number of neighbors, and the node ID and the neighbor count field are each designed to be 1 byte.

[0016] Preferably, it is stipulated that only one relay node is included in two node combinations, and only the leader node and the relay node have the ability to forward data packets. Since ordinary nodes do not have the forwarding ability, when receiving data packets from other nodes, they directly discard them, and the ordinary nodes can only communicate with the leader node.

[0017] Preferably, when the source node has a need to transmit data packets to the destination node, the shortest path among all transmission paths is obtained through route detection and route reply, including:

[0018] The source node sends a route detection packet to the leader node within its node combination, requesting the route path to the destination. First, the leader node searches for the destination among its managed neighbor nodes. If the destination does not belong to the members of this node combination, the leader node forwards the route detection packet to the relay node within its combination. The relay node then forwards the route detection packet to the leader node of another node combination. The leader node of another node combination searches for the destination in its neighbor node list, and the search process continues until the destination node is found. When the route detection packet reaches the node combination of the target node, the leader node of this node combination selects the shortest path from multiple paths according to the hop count and responds to the previous node along the shortest path using a route reply packet;

[0019] Furthermore, both the route detection packet and the route reply packet are broadcast packets of the Mesh Message type, and the data carried is the ID of its own node, with a size of 1 byte.

[0020] The beneficial effects of the present invention: By designing the routing protocol to restrict the forwarding of ordinary nodes and only allowing the leader node and the relay node to forward data packets, the number of forwarding nodes is reduced, so as to achieve the purpose of suppressing redundant data packets, thereby reducing network energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a flowchart of the node - combination - based on - demand routing method for BLE Mesh energy optimization of the present invention;

[0022] Figure 2 It is a schematic diagram of the neighbor node information exchange packet of the present invention;

[0023] Figure 3 It is a schematic diagram of the node discovery process of the present invention;

[0024] Figure 4Schematic diagram of the information unit of the present invention;

[0025] Figure 5 Schematic diagram of the node role configuration process of the present invention;

[0026] Figure 6 Schematic diagram of the process for all nodes in the node combination of the present invention to achieve full connection;

[0027] Figure 7 Routing establishment process diagram of the present invention. Detailed implementation manners

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] A node combination routing method based on a BLE Mesh network, as Figure 1 shown, includes:

[0030] Node combination topology establishment: Divide the BLE Mesh network nodes into a node combination topology structure through neighbor node information exchange, node role configuration, and full connection of node combinations;

[0031] Routing establishment: When the source node has a need to transmit data packets to the destination node, obtain the shortest path among all transmission paths through route detection and route reply, and the data packets sent by the source node are sequentially transmitted to the destination node along the shortest path.

[0032] The node combination routing protocol consists of 2 stages: Stage 1 is node combination topology establishment. Through 3 steps of neighbor node information exchange, node role configuration, and full connection of node combinations, the network topology is divided into a node combination topology structure; Stage 2 is routing establishment. When the source node has a need to transmit data packets to the destination node, obtain the shortest path packet among all transmission paths through 2 steps of route detection and route reply, and the data packets are sequentially transmitted to the destination node along the found shortest path.

[0033] The node combination topology establishment is divided into 3 steps. Step 1 is neighbor node information exchange, and obtain its own neighbor information and the neighbor count of the neighbor node through neighbor node information exchange; Step 2 is node combination configuration, and assign leadership roles and ordinary roles according to the neighbor node information; Step 3 is to achieve full connection of node combinations, upgrade some ordinary nodes to relay nodes, and update the roles of the upgraded relay nodes to make all nodes in the entire network reachable.

[0034] Through the establishment of a node combination topology, the BLE Mesh network nodes can be divided into different node combinations. The node roles in each node combination include leader, relay, and ordinary types. To reduce complexity and prevent information exchange overload between two node combinations, it is stipulated that only one relay node is included in two node combinations, and only the leader node and the relay node have the ability to forward data packets. Since ordinary nodes do not have the forwarding ability, when receiving data packets from other nodes, they directly discard them, and ordinary nodes can only communicate with the leader node.

[0035] Due to the limited length of the data packets in the BLE Mesh network, it is not only difficult to encapsulate neighbor node information into the data packets, but also the information unit can only be updated passively when sending data. Therefore, a Mesh Beacon type of broadcast packet is used to actively update the information unit.

[0036] The BLE Mesh standard specification defines two types of beacons. One is the unprovisioned beacon with a beacon type value of 0x00; the other is the secure network beacon with a beacon type value of 0x01. The beacon type is defined as 1 byte, and the remaining 0x02 - 0xFF are defined as reserved bits. In the present invention, any one of the reserved bit beacons in the reserved bits of 0x02 - 0xFF is selected as the neighbor node information exchange beacon, and its carrier is a non-directional non-connectable broadcast packet, such as Figure 2 shown. Each node only needs to collect the ID and the number of neighbors of the neighbor nodes. Therefore, the data part of the broadcast packet only contains the above two fields. The node ID and the neighbor count field of the present invention are designed as 1 byte. During the neighbor node information exchange process, the BLE node collects the ID and the number of neighbors information of adjacent nodes by exchanging one-hop broadcast packets. The node discovery process is as Figure 3 shown. Whenever a broadcast packet is received, the BLE node updates its own information unit. The information unit design is as Figure 4 shown. The initial value of the number of neighbors is set to 0, and the rest of the fields are empty.

[0037] After the neighbor node information exchange, each BLE node has obtained the node with the largest number of neighbors within the wireless communication range. Considering the energy consumption problem, a leader node should be responsible for managing as many nodes as possible. Therefore, the BLE node with the largest neighbor count is selected as the leader node; when there is a situation where the neighbor counts are the same, the node with the shortest total distance to all neighbor nodes is selected as the leader node, and its role is upgraded to the leader node. The remaining nodes are defined as ordinary nodes, and their roles are updated to ordinary nodes. The node role configuration process is as Figure 5 shown.

[0038] After the node roles are configured, each node combination is relatively isolated. To achieve the function of mutual communication, a bridge between isolated node combinations needs to be built, and some ordinary nodes are upgraded to relay nodes to complete the mutual connection of isolated node combinations, so as to achieve that any node in the entire network is reachable. The present invention defines that any node in the network being reachable as the node combination achieving full connectivity; among them, the upgrading steps are as follows:

[0039] (1) The leader node searches for adjacent nodes, and nodes within the wireless communication range of the leader node but not belonging to this combination are added to the candidate node set of the relay node;

[0040] (2) When the leader node finds multiple candidate relay nodes in the same adjacent node combination, the point with the smallest average distance from the leader nodes of the two node combinations is selected to be upgraded to a relay node;

[0041] (3) The upgraded relay node updates its own role to a relay and uses the leader node ID as the ID of the second node combination it belongs to.

[0042] The process diagram of the node combination achieving full connectivity is as Figure 6 shown.

[0043] After the node combination type topology is established, when the source node needs to transmit data packets to the destination node, to further reduce the amount of data in the network, the source node needs to find the shortest path to the destination node. The method considered by the present invention is: the source node uses a routing probe packet to determine the shortest path according to the shortest number of hops, and the destination node uses a routing reply packet to notify the source node.

[0044] Both the routing probe packet and the routing reply packet are broadcast packets of the Mesh Message type, carrying the ID of its own node, with a size of 1 byte. Since it is a broadcast packet, when a node sends this type of data packet, all nodes within the radio range can receive it, but only specific nodes can perform the next forwarding.

[0045] The routing establishment process is as Figure 7 shown. The source node forwards the routing probe packet to its leader node, requesting the routing path to the destination. First, the leader node searches for the destination among the neighbor nodes it manages. If the destination does not belong to the members of this node combination, the leader node forwards the routing probe packet to its relay node, and the relay node then forwards the routing probe packet to the leader node of its second node combination. The leader node of the other node combination searches for the destination in its neighbor list. This process will continue until the destination node is found. When the routing probe packet reaches the node combination of the target node, the leader node of this node combination selects the shortest path from multiple paths according to the number of hops and responds to the previous node along the shortest path using a routing reply packet.

[0046] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A node combined routing method based on BLE Mesh network, characterized in that: include: S1: Node combination topology establishment: BLE Mesh network nodes are divided into node combination topology structures through neighbor node information exchange, node role configuration and node combination full connectivity; Neighbor node information exchange: Select any reserved bit beacon on the reserved bit of 0x02-0xFF as the neighbor node information exchange beacon, and use the non-directional non-connectable broadcast packet of Mesh Beacon type as the carrier of the neighbor node beacon message. During the neighbor node information exchange process, the BLE node exchanges the neighbor node one-hop broadcast packet, and the BLE node updates the information unit according to the neighbor node ID and neighbor number information in the broadcast packet; Node role configuration: According to the updated information units of all BLE nodes, the BLE node with the largest neighbor count is selected as the leader node. When the neighbor counts are the same, the BLE node with the closest total distance to all neighbor nodes is selected as the leader node and its role is updated to leader. The remaining BLE nodes are normal nodes and their roles are updated to normal. The node combination is fully connected: The leader node searches for adjacent nodes and adds nodes that do not belong to the current combination to the candidate node set composed of relay nodes within the wireless communication range of the leader node. When the leader node finds multiple candidate relay nodes in the same adjacent node combination, the node with the smallest average distance from the leader nodes in the two node combinations is selected from the candidate node set and upgraded to a relay node. The upgraded relay node updates its role to a relay and uses the leader node ID as the ID of the second node combination to which it belongs. S2: Route establishment: When the source node needs to transmit a data packet to the destination node, the shortest path among all transmission paths is obtained through route detection and route reply. The data packet sent by the source node is transmitted to the destination node along the shortest path.

2. According to a node combined routing method based on a BLE Mesh network according to claim 1, it is characterized in that: The broadcast packet for neighbor node information exchange includes: Since each node only needs to collect the neighbor node ID and neighbor count, the data part of the broadcast packet is designed to contain only two fields: the neighbor node ID and the neighbor count, and the node ID and neighbor count fields are each designed to be 1 byte.

3. According to a node combined routing method based on BLE Mesh network according to claim 1, it is characterized in that: The node combination includes: It is stipulated that only one relay node is included in the combination of two nodes, and only the leading node and the relay node have the ability to forward data packets. Ordinary nodes do not have the forwarding ability and directly discard data packets received from other nodes. Moreover, the ordinary nodes can only communicate with the leading node.

4. According to a node combined routing method based on BLE Mesh network according to claim 1, it is characterized in that: When the source node needs to transmit a data packet to the destination node, the shortest path among all transmission paths is obtained through route detection and route reply, including: The source node sends a routing detection packet to the leader node in its node combination, requesting the routing path to the destination. First, the leader node searches for the destination among the neighboring nodes it manages. If the destination is not a member of this node combination, the leader node forwards the routing detection packet to the relay node in its node combination. The relay node then forwards the routing detection packet to the leader node of another node combination. The leader node in the other node combination searches for the destination in its neighbor node list and continues the search process until the destination node is found. When the routing detection packet reaches the node combination of the target node, the leader node of the node combination selects the shortest path from multiple paths based on the number of hops, and responds to the previous node along the shortest path using a routing reply packet.

5. A node combined routing method based on a BLE Mesh network according to claim 4, characterized in that: The routing detection packet and routing reply packet are both Mesh Message type broadcast packets, and the data carried is the node ID itself, with a size of 1 byte.

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