A method for extending the service life of a Bluetooth temperature sensor

Abstract

The invention discloses a method for extending the service life of a Bluetooth temperature sensor, comprising the following steps: step 1: calculating an evaluation function of a Bluetooth temperature and humidity sensor; step 2: selecting the Bluetooth temperature and humidity sensor as a node for vehicle data collection; step 3: constructing an optimal network route; step 4: using the Bluetooth temperature and humidity sensor selected by the evaluation function in step 1 to construct a path for industrial vehicle data collection; step 5: after the node traversal of the Bluetooth temperature and humidity sensor is completed, recording the final vehicle path and network route. In the sensor network, the invention uses the directed betweenness centrality, neighbor nodes and hop distance of the node as evaluation factors to select a high-load sensor node as a convergence node, balance the energy consumption between nodes, alleviate the "energy hole" problem, ensure that the energy consumption of the Bluetooth temperature and humidity sensor is more balanced, and extend the service life of the Bluetooth temperature and humidity sensor network.

Description

Technical Field

[0001] The present invention relates to the technical field of network communication, and in particular to a method for extending the service life of a Bluetooth temperature sensor. Background Art

[0002] Bluetooth temperature and humidity sensors are often placed in greenhouses to collect temperature and humidity information in the greenhouses to observe the growth of vegetables and fruits. Bluetooth temperature and humidity sensors do not have the function of connecting to the network and cannot directly transmit data through the network. The data transmission of Bluetooth temperature and humidity sensors is to form a wireless sensor network through the Bluetooth function for self-organizing networking. After collecting all the data in the network, the data is transmitted to the base station with an Internet access module, and then the temperature and humidity in the greenhouse are observed through the network. However, the data transmission mode of Bluetooth temperature and humidity sensors will form an energy hole problem, resulting in excessive energy consumption of some Bluetooth temperature and humidity sensors, which greatly shortens their lifespan. This situation will also make the collected greenhouse data information incomplete information. When extending the lifespan in existing sensor networks, the centralized expression factor of the sensor can usually represent the load situation, but for directional data transmission networks, the previous centralized expression factor is not enough to describe the load situation of the sensor.

[0003] Therefore, a method for extending the service life of a Bluetooth temperature sensor is proposed to increase the service life of the network and make data collection complete. Summary of the invention

[0004] In order to solve the deficiencies in the above-mentioned prior art, the present invention provides a method for extending the service life of a Bluetooth temperature sensor, proposes an evaluation function consisting of the directed betweenness and hop distance of the temperature and humidity sensor nodes and neighbor nodes, constructs network routing, solves the energy imbalance problem, thereby improving the service life of the network and making data collection complete.

[0005] The object of the present invention is achieved in that:

[0006] A method for extending the service life of a Bluetooth temperature sensor comprises the following steps: step 1: calculating an evaluation function of a Bluetooth temperature and humidity sensor; step 2: selecting a Bluetooth temperature and humidity sensor as a node for vehicle data collection; step 3: constructing an optimal network route; step 4: using the Bluetooth temperature and humidity sensor selected by the evaluation function in step 1 to construct a path for industrial vehicle data collection; step 5: after the node traversal of the Bluetooth temperature and humidity sensor is completed, recording the final vehicle path and network route.

[0007] The evaluation function in step 1 is:

[0008]

[0009] Ii For node s i Importance evaluation index; θ i represents the directed betweenness centrality of a node; H(i, V RP ) is node s i To the nearest V RP The jump distance of (m) (i) is node s i The set of m-order neighbor nodes; α and γ are two adjustable parameters, which are used to adjust the node's dependence on the node's own characteristics and 1- to m-order neighbor nodes respectively; α is used to adjust the dependence on the current node, and γ is used to adjust the dependence on 1- to m-order neighbor nodes; the values ​​of α and γ are defined to satisfy 1>a>0 and 1>γ>0.

[0010] In step 3, the Bluetooth temperature and humidity sensor with the largest energy consumption in the Bluetooth temperature and humidity sensor network constructs the optimal network route. In the Bluetooth temperature and humidity sensor network, the degree of the Bluetooth temperature and humidity sensor node represents the number of adjacent nodes. According to the relay transmission property of the network, the more neighbor nodes a Bluetooth temperature and humidity sensor node has, the more data packets it receives. The higher the degree of the Bluetooth temperature and humidity sensor node, the greater the load it can bear; when receiving and forwarding data, the greater the energy consumed; according to the energy model, the betweenness of the Bluetooth temperature and humidity sensor node reflects the degree of centralization of the node in the network; when the degree of centralization of the sensor node in the sensor network is higher, the amount of messages passing through this node is greater; when the betweenness of a Bluetooth temperature and humidity sensor node is larger, it needs sufficient storage space to forward data and the energy consumption of forwarding data is greater; select the Bluetooth temperature and humidity sensor node with high degree and directed betweenness as the confluence node, and the expression of directed betweenness is as follows:

[0011]

[0012] θ i Represents the directed betweenness centrality of the node, m k (i) indicates that the shortest path for node k to transmit data to the confluence node passes through node s i The number of paths; m k V represents the number of shortest paths from node k to the confluence node; k It is represented as a set of non-convergent nodes. For a network with n sensor nodes, the shortest path from other nodes in the network to the target node passes through node s i , at this time node s i The wireless sensor has a directed betweenness centrality θ i is 1.

[0013] In step 4, the shortest vehicle movement trajectory is constructed using the traveling salesman model algorithm to collect data from Bluetooth temperature and humidity sensors in the entire network;

[0014] The formula of the traveling salesman model is: The formula to ensure that the constructed moving trajectory is less than the set maximum moving distance is:

[0015]

[0016] The Hamiltonian circuit formula is:

[0017] Ensure there is only one loop

[0018] d ij represents the distance from Bluetooth temperature and humidity sensor i to Bluetooth temperature and humidity sensor j, X ij is a decision variable. There is only one Hamiltonian circuit among all the given paths. ij =1 means (i, j) is in the Hamiltonian circuit, otherwise not, P represents the set of Bluetooth temperature and humidity sensors accessed {p 1 ,p 2 ,p 3 ,...,p n}, V is the set of all Bluetooth temperature and humidity sensor nodes, L max The maximum moving track distance of the vehicle is set.

[0019] Positive and beneficial effects: In the sensor network, the present invention uses the directed betweenness centrality, neighbor nodes and hop distance of the node as evaluation factors to select high-load sensor nodes as convergence nodes, balance the energy consumption between nodes, alleviate the "energy hole" problem, ensure that the energy consumption of the Bluetooth temperature and humidity sensor is more balanced, and improve the service life of the Bluetooth temperature and humidity sensor network. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flowchart of the present invention;

[0021] Figure 2 The comparison of network life between the original method and the method provided by the present invention under different Bluetooth temperature and humidity quantities is shown. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0023] like Figure 1 As shown, a method for extending the service life of a Bluetooth temperature sensor comprises the following steps:

[0024] Step 1: Calculate the evaluation function of the Bluetooth temperature and humidity sensor; the evaluation function is

[0025]

[0026] I i For node s i Importance evaluation index; θ i represents the directed betweenness centrality of a node; H(i, V RP ) is node s i To the nearest V RP The jump distance of (m) (i) is node s i The set of m-order neighbor nodes; α and γ are two adjustable parameters, which are used to adjust the node's dependence on the node's own characteristics and 1- to m-order neighbor nodes respectively; α is used to adjust the dependence on the current node, and γ is used to adjust the dependence on 1- to m-order neighbor nodes; the values ​​of α and γ are defined to satisfy 1>α>0 and 1>γ>0.

[0027] Step 2: Select the Bluetooth temperature and humidity sensor as the node for vehicle data collection.

[0028] Step 3: Construct the optimal network route; The Bluetooth temperature and humidity sensor with the largest energy consumption in the Bluetooth temperature and humidity sensor network constructs the optimal network route. In the Bluetooth temperature and humidity sensor network, the degree of the Bluetooth temperature and humidity sensor node represents the number of adjacent nodes. According to the relay transmission properties of the network, the more neighbor nodes a Bluetooth temperature and humidity sensor node has, the more data packets it receives. The higher the degree of the Bluetooth temperature and humidity sensor node, the greater the load it can bear; when receiving and forwarding data, the greater the energy consumed; according to the energy model, the betweenness of the Bluetooth temperature and humidity sensor node reflects the degree of centralization of the node in the network; when the sensor node is transmitting The higher the degree of centralization in the sensor network, the greater the amount of messages passing through this node; when the betweenness of a Bluetooth temperature and humidity sensor node is larger, it needs sufficient storage space to forward data and the energy consumption of forwarding data is also greater; selecting Bluetooth temperature and humidity sensor nodes with high degree and directed betweenness as confluence nodes is conducive to avoiding data overflow due to insufficient storage space and reducing node energy loss, thereby improving the life cycle of the sensor network; in previous work, we proposed a new betweenness index - directed betweenness index, which can accurately reflect the data transmission direction of the node; therefore, this article still uses this indicator; the expression of directed betweenness is as follows:

[0029] θ i Represents the directed betweenness centrality of the node, m k (i) indicates that the shortest path for node k to transmit data to the confluence node passes through node s i The number of paths; m k V represents the number of shortest paths from node k to the confluence node;k It is represented as a set of non - confluent nodes. For a network with n sensor nodes, the shortest paths from other nodes in the network to the target node all pass through node s i , at this time node s i has a wireless sensor betweenness centrality θ i of 1.

[0030] Step 4: Select the Bluetooth temperature and humidity sensors selected by the evaluation function in Step 1 to construct the path for industrial vehicle data collection; use the traveling salesman model algorithm to construct the shortest vehicle movement trajectory to collect the data of the Bluetooth temperature and humidity sensors in the entire network

[0031] The formula of the traveling salesman model is: The formula for ensuring that the constructed movement trajectory is less than the set maximum movement distance is:

[0032]

[0033] The formula of the Hamiltonian cycle is:

[0034] Ensure that there is only one cycle,

[0035] d ij represents the distance from Bluetooth temperature and humidity sensor i to Bluetooth temperature and humidity sensor j, X ij is a decision variable. Among all the given paths, there is only one Hamiltonian cycle. X ij = 1 indicates that (i, j) is in the Hamiltonian cycle, otherwise it is not. P represents the set of Bluetooth temperature and humidity sensors to be visited {p 1 , p 2 , p 3 ,..., p n}, V is the set of all Bluetooth temperature and humidity sensor nodes, and L max is the set maximum movement trajectory distance of the vehicle set.

[0036] Step 5: After traversing all the nodes of the Bluetooth temperature and humidity sensors, record the final vehicle path and network routing. If all the nodes of the Bluetooth temperature and humidity sensors have not been traversed, return to Step 2 to continue.

[0037] In the sensor network of the present invention, the betweenness centrality, neighbor nodes, and hop distance of the nodes are used as evaluation factors to select high - load sensor nodes as confluent nodes, balance the energy consumption between nodes, alleviate the "energy hole" problem, ensure that the energy consumption of the Bluetooth temperature and humidity sensors is more balanced, and improve the service life of the Bluetooth temperature and humidity sensor network.

[0038] Example:

[0039] The entire Bluetooth temperature and humidity sensor deployment area is 400m×400m. The Bluetooth temperature and humidity sensor nodes are randomly distributed in this area. The number of deployed Bluetooth temperature and humidity nodes is 10-200, and the maximum communication range is 20m. The sensor nodes do not move after deployment. The sink node moves in the monitoring area at a fixed speed of 1m / s. The initial energy of all sensor nodes is 5J. The adjustable parameters are assumed to be α=1 and γ=0.5

[44] .

[0040] Other parameters are shown in the table. In order to reduce errors, all experimental data are the mean of 50 random tests.

[0041] parameter value <![CDATA[Maximum moving sink travel distance (L max )]]> 100m-300m Monitoring area 200m×200m Number of sensor nodes (n) 10-200 Speed ​​of moving sink (υ) 1m / s Packet length (b) 240 bits Point communication radius (R) 20m

[0042] like Figure 2 As shown, the network life of the original method and the method provided by the present invention under different Bluetooth temperature and humidity numbers is compared. It can be seen from the figure that as the number of Bluetooth temperature and humidity increases, the amount of data that the sensor nodes in the network need to forward also increases, and the life of the Bluetooth temperature and humidity becomes shorter under the premise that the initial energy of the node remains unchanged. When using the method provided by this patent, the service life of the Bluetooth temperature and humidity sensor network is greatly improved.

Claims

1. A method for extending the service life of a Bluetooth temperature sensor, Features: The method comprises the following steps: step 1: calculating the evaluation function of the Bluetooth temperature and humidity sensor; step 2: selecting the Bluetooth temperature and humidity sensor as the node for vehicle data collection; step 3: constructing the optimal network route; step 4: using the Bluetooth temperature and humidity sensor selected by the evaluation function in step 1 to construct the path for industrial vehicle data collection; step 5: after the node traversal of the Bluetooth temperature and humidity sensor is completed, recording the final vehicle path and network route; the evaluation function in step 1 is l i For node s i Importance evaluation index; θ i represents the directed betweenness centrality of a node; H(i, V RP ) is node s i To the nearest V RP The jump distance of (m) (i) is node s i The set of m-order neighbor nodes; α and γ are two adjustable parameters, which are used to adjust the degree of dependence of the node on its own characteristics and 1 to m-order neighbor nodes respectively; α is used to adjust the degree of dependence on the current node, and γ is used to adjust the degree of dependence on neighboring nodes of order 1 to m. The values ​​of α and γ are defined to satisfy 1>α>0 and 1>γ>0. In step 3, an optimal network route is constructed using the Bluetooth temperature and humidity sensor with the largest energy consumption in the Bluetooth temperature and humidity sensor network. In the Bluetooth temperature and humidity sensor network, the degree of the Bluetooth temperature and humidity sensor node represents the number of adjacent nodes. According to the energy model, the betweenness of the Bluetooth temperature and humidity sensor node reflects the degree of centralization of the node in the network; the Bluetooth temperature and humidity sensor nodes with high degree and directed betweenness are selected as the confluence nodes. The expression of directed betweenness is as follows: θ i Represents the directed betweenness centrality of the node, m k (i) indicates that the shortest path for node k to transmit data to the confluence node passes through node s i The number of paths; m k V represents the number of shortest paths from node k to the confluence node; k It is represented as a set of non-convergent nodes. For a network with n sensor nodes, the shortest path from other nodes in the network to the target node passes through node s i , at this time node s i The wireless sensor has a directed betweenness centrality θ i is 1; In step 4, the shortest vehicle movement trajectory is constructed using the traveling salesman model algorithm to collect data from Bluetooth temperature and humidity sensors in the entire network; The formula of the traveling salesman model is: The formula to ensure that the constructed moving trajectory is less than the set maximum moving distance is: The Hamiltonian circuit formula is: Ensure that there is only one loop d ij represents the distance from Bluetooth temperature and humidity sensor i to Bluetooth temperature and humidity sensor j, x ij is a decision variable. There is only one Hamiltonian circuit among all the given paths. ji =1 means (i, j) is in the Hamiltonian circuit, otherwise not, P represents the set of Bluetooth temperature and humidity sensors accessed {p 1 ,p 2 ,p 3 ,...,p n }, V is the set of all Bluetooth temperature and humidity sensor nodes, L max The maximum moving track distance of the vehicle is set.

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