Wireless sensor network monitoring data forwarding method

Abstract

The invention discloses a wireless sensor network monitoring data forwarding method. A wireless sensor network comprises a plurality of sensor nodes. The monitoring data forwarding method comprises the following steps: dividing a plurality of sensor nodes of a wireless sensor network into a plurality of initial clusters; the base station maintains cluster state information of the initial cluster through a cluster state maintenance algorithm based on a prediction mechanism; the base station receives a user query message and determines a to-be-sent cluster according to a target node of the user query message; the base station calculates forwarding efficiency corresponding to neighbor clusters of the to-be-transmitted cluster according to the cluster state information based on a decision basis, and determines at most two to-be-forwarded clusters according to the forwarding efficiency; repeating the steps until the forwarding path of the to-be-forwarded cluster which is forwarded for multiple times is determined; and the base station sends the forwarding path to the to-be-sent cluster, and the to-be-sent cluster and the to-be-forwarded cluster sequentially forward the monitoring data according to the forwarding path until the monitoring data reach the base station. According to the invention, the energy consumption of each cluster in the network is kept balanced and the energy consumption in the data transmission process is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless sensor networks, and in particular to a method for forwarding monitoring data of a wireless sensor network. Background Art

[0002] In the clustering protocols developed in recent years, the sensor nodes in the network are divided into multiple clusters according to their positions. Each cluster has multiple nodes, and the distance between sensor nodes is relatively close. In the process of collecting monitoring data of each node in the wireless sensor network, since the nodes in the cluster are relatively close to each other, the cluster head can directly communicate with other nodes in the cluster and collect their monitoring data. This process is called intra-cluster communication. After the cluster head collects the monitoring data of all nodes in the cluster, the cluster head forwards the data to one of the cluster heads based on the relevant status information of the surrounding cluster heads. After several forwardings by different cluster heads, the data is finally forwarded to the base station near the wireless sensor network and reaches the user's cloud server. This process is called inter-cluster routing.

[0003] In the inter-cluster routing phase of the above protocol, since each time data is forwarded between cluster heads, the existing routing protocol only considers the status information of the cluster heads or clusters around the current cluster head holding the data, but does not consider the information of other clusters in the entire network, the monitoring data forwarding method of the prior art is prone to form a local optimum rather than a global optimum. The above situation is likely to lead to uneven energy consumption of each cluster in the network, causing some nodes to die prematurely, thereby reducing the survival time of the entire wireless sensor network. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present invention aims to provide a method for forwarding monitoring data in a wireless sensor network, which can not only consider the situation of surrounding clusters that are close to the cluster in the inter-cluster routing stage, but also consider the status information of other related clusters in the network.

[0005] The present invention is implemented according to the following scheme:

[0006] A method for forwarding monitoring data of a wireless sensor network is provided. The wireless sensor network includes a plurality of sensor nodes. The method for forwarding monitoring data includes:

[0007] Dividing a plurality of sensor nodes of the wireless sensor network into a plurality of initial clusters;

[0008] The base station maintains the cluster state information of the initial cluster through a cluster state maintenance algorithm based on a prediction mechanism;

[0009] The base station receives a user query message, and determines a cluster to be sent according to a target node of the user query message;

[0010] The base station calculates forwarding efficiencies corresponding to neighboring clusters of the to-be-transmitted cluster according to the cluster state information, and determines at most two to-be-transmitted clusters according to the forwarding efficiencies;

[0011] Repeat the above steps until a forwarding path is determined, where the forwarding path is a path for forwarding the monitoring data of the to-be-sent cluster to the base station, and the forwarding path includes the to-be-sent cluster that is forwarded multiple times;

[0012] The base station sends the forwarding path to the to-be-sent cluster, and the to-be-sent cluster and the to-be-forwarded cluster sequentially forward the monitoring data according to the forwarding path until the monitoring data reaches the base station.

[0013] Compared with the prior art, the beneficial effects of a wireless sensor network monitoring data forwarding method provided by the present invention are as follows: the base station uses a cluster state maintenance algorithm based on a prediction mechanism to keep the state information maintenance cost of all clusters in the entire network at a very low level. At the same time, the base station uses the cluster state information maintained by itself to calculate the forwarding efficiency of various possible paths of the monitoring data from the cluster to be sent to the base station, and selects the best path from them. In addition, the monitoring data is transmitted through multiple paths through multiple clusters to be forwarded to avoid excessive energy consumption of related nodes in the forwarding path caused by the monitoring data being transmitted through a single path. The above three mechanisms make the energy consumption of each cluster in the network more balanced and reduce the energy consumption during data transmission.

[0014] Optionally, the cluster state information includes location information, predicted remaining energy, a shortest path, and total remaining energy of the initial cluster; and the base station maintains the cluster state information of the initial cluster by a cluster state maintenance algorithm based on a prediction mechanism, including:

[0015] The cluster head of the initial cluster determines the centroid coordinates of the initial cluster and sends them to the base station;

[0016] The base station determines the centroid coordinates as the location information;

[0017] The base station determines the predicted remaining energy according to the current round number;

[0018] The base station determines the shortest path and the total remaining energy according to the location information and the predicted remaining energy.

[0019] Optionally, the base station determines the predicted remaining energy according to the current round number, including:

[0020] When the current round number is less than or equal to ten rounds, the predicted remaining energy corresponding to the initial cluster is not calculated;

[0021] When the current round number is greater than ten rounds, the cluster head of the initial cluster performs statistics on the weighted average query energy consumption of its corresponding cluster set; the cluster set includes the current cluster and the cluster to which the current cluster needs to forward data; the cluster to which the current cluster needs to forward data is the cluster to which the current cluster needs to forward data in the historical time round;

[0022] According to the weighted average query energy consumption, the initial cluster calculates its predicted remaining energy when the current round number is greater than ten rounds.

[0023] Optionally, when the current round number is greater than ten rounds, the cluster head of the initial cluster performs statistics on the weighted average query energy consumption of its corresponding cluster set, including:

[0024] Determine the residual energy of each round and the weighted average query frequency of the corresponding cluster set when the initial cluster is less than or equal to ten rounds. The calculation formula is as follows:

[0025] p k =(x1*f1+x2*f2+…+x n *f n ) / n;

[0026] Where k is the time period from the current round number to less than or equal to ten rounds, p k is the weighted average query frequency of the cluster set in the kth round, n is the number of clusters in the cluster set to which the cluster needs to forward data, and f n is the number of times the node of the nth cluster in the cluster set is queried by the user, x n is the weight corresponding to the nth cluster in the cluster set, and the weight is the ratio of the frequency of data of this cluster being forwarded by this cluster to the frequency of data being sent by this cluster in the historical time round;

[0027] According to the round residual energy and the weighted average query frequency, the cluster head of the initial cluster performs statistics on the weighted average query energy consumption of its corresponding cluster set, and the calculation formula is as follows:

[0028] C=(E i-9 -E i ) / (p i +p i-1 +...+p i-9 )

[0029] Where C is the weighted average query energy consumption, E i-9 is the residual energy of the first round in the time period, E i is the remaining energy of the tenth round in the time period, p i ~p i-9 It is the weighted average query frequency of each round within the time period.

[0030] Optionally, the initial cluster calculates its predicted remaining energy according to the weighted average query energy consumption when the current round number is greater than ten rounds, including:

[0031] determining a final round residual energy of the initial cluster in a tenth round within a time period;

[0032] According to the weighted average query energy consumption of the ten historical rounds, the prediction parameters of the linear regression model based on the least squares method are determined, and the calculation formula is as follows:

[0033]

[0034] Where k is the time period from the current round number to less than or equal to ten rounds, C k is the historical weighted average query energy consumption of each initial cluster in the kth round, a and b are prediction parameters;

[0035] A prediction formula is constructed based on the final round remaining energy and the calculated prediction parameters, and its expression is as follows:

[0036]

[0037] Where k is the time period from the current round number to less than or equal to ten rounds, C k is the weighted average query energy consumption predicted by each initial cluster in the kth round, A j is the predicted remaining energy of the cluster in round j (j>i), E i is the remaining energy of the tenth round in the time period, p k is the weighted average query frequency of the cluster set corresponding to this cluster in the kth round;

[0038] The cluster head of the initial cluster calculates the predicted residual energy of each future round through the prediction formula.

[0039] Optionally, the cluster head of the initial cluster receives the node residual energy of each member node, and determines the sum of the node residual energy of each member node as the actual residual energy of each cluster; when the difference between the actual residual energy and the predicted residual energy is greater than a preset threshold, the prediction formula is updated, including:

[0040] Updating the final round remaining energy to the actual remaining energy of the current round;

[0041] Recalculate the weighted average query energy consumption based on the current round and the conditions within ten rounds;

[0042] The cluster head of the initial cluster determines a new prediction parameter according to the weighted average query energy consumption and the actual remaining energy of the current round, and sends the actual remaining energy of the current round and the new prediction parameter to the base station;

[0043] The base station updates the prediction formula according to the received actual remaining energy of the corresponding cluster in the current round and the new prediction parameter.

[0044] Optionally, the base station determines the shortest path and the total remaining energy according to the location information and the predicted remaining energy, including:

[0045] Determine the shortest path according to the location information, where the shortest path is a path from the initial cluster to the base station passing through the least number of clusters;

[0046] The total remaining energy is determined according to the predicted remaining energy and the shortest path, where the total remaining energy is the sum of the predicted remaining energies from the initial cluster to the clusters passed by the base station.

[0047] Optionally, the base station calculates forwarding efficiencies corresponding to neighboring clusters of the to-be-sent cluster according to the cluster state information based on a decision basis, and determines at most two to-be-forwarded clusters according to the forwarding efficiencies, including:

[0048] determining an average residual energy of a plurality of initial clusters of the wireless sensor network;

[0049] Based on the predicted remaining energy, the shortest path and the total remaining energy, calculating the forwarding efficiencies corresponding to the neighboring clusters of the to-be-sent cluster respectively;

[0050] The neighbor clusters are sorted from large to small according to their corresponding forwarding efficiencies;

[0051] When the number of the neighbor clusters is greater than two, selecting the first two neighbor clusters in the ranking as the to-be-forwarded clusters;

[0052] When the number of the neighbor clusters is less than or equal to two, all neighbor clusters are selected as the clusters to be forwarded.

[0053] Optionally, the base station sends the forwarding path to the to-be-forwarded cluster, and the to-be-sent cluster and the to-be-forwarded cluster sequentially forward the monitoring data according to the forwarding path until the monitoring data reaches the base station, including:

[0054] The base station determines the sub-monitoring data to be forwarded by the to-be-forwarded cluster at each forwarding according to the forwarding path;

[0055] The cluster to be sent sends the sub-monitoring data to the corresponding cluster to be forwarded respectively, wherein the sub-monitoring data is obtained by dividing the monitoring data based on the number of clusters to be forwarded each time and the forwarding efficiency;

[0056] The above steps are repeated according to the forwarding order of the forwarding path until the monitoring data is forwarded to the base station.

[0057] Optionally, the decision-making basis is a formula for calculating the forwarding efficiency, as follows:

[0058]

[0059] Among them, H is the forwarding efficiency, E0 is the value of the predicted remaining energy, D is the value of the shortest path length, and E T is the total remaining energy value, E avg The value of the average residual energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 The figure is a flow chart of the monitoring data forwarding method of the present invention. DETAILED DESCRIPTION

[0061] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0062] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0063] See also Figure 1 As shown, the present invention provides a method for forwarding monitoring data of a wireless sensor network, wherein the wireless sensor network includes a plurality of sensor nodes; the method for forwarding monitoring data includes:

[0064] S1: Divide multiple sensor nodes of the wireless sensor network into multiple initial clusters, including:

[0065] Firstly, the physical distances between multiple sensor nodes are determined, and then based on a clustering protocol, multiple sensor nodes in a wireless sensor network are divided into multiple initial clusters according to the physical distances, each of which includes multiple sensor nodes with relatively short physical distances.

[0066] The status information of the initial cluster includes the location information of the initial cluster, the predicted residual energy, the shortest path and the total residual energy, wherein the shortest path is the path from the initial cluster to the base station passing through the least number of clusters, and the total residual energy is the sum of the predicted residual energies of the clusters passed in the shortest path.

[0067] S2: The base station maintains the cluster state information of the initial cluster through a cluster state maintenance algorithm based on a prediction mechanism, including:

[0068] First, the centroid coordinates of the initial cluster are determined by the cluster head of each initial cluster and sent to the base station; the centroid coordinates are the average latitude and longitude coordinates of all sensor nodes in the initial cluster; the base station determines the received centroid coordinates as the location information of each initial cluster.

[0069] The base station saves the location information in the local full-network cluster status database, broadcasts the location information of all initial clusters, and all initial clusters receive the information broadcast by the base station. The cluster set of the cluster where the monitoring data forwarded by each initial cluster is located is determined according to the information broadcast by the base station.

[0070] The remaining energy is predicted based on the current round number, including:

[0071] Determine the current round number of the wireless sensor network, and determine whether the current round number is greater than ten rounds. When the current round number is less than or equal to ten rounds, the predicted remaining energy corresponding to the initial cluster is not calculated. When the current round number is greater than ten rounds, a cluster state maintenance algorithm based on a prediction mechanism is used to calculate the predicted remaining energy corresponding to the initial cluster. During the operation of the wireless sensor network, the energy consumption of the nodes in the first ten rounds accounts for a very small proportion of the total energy. Therefore, it is considered that the remaining energy of all initial clusters in the wireless sensor network is basically the same, that is, only the predicted remaining energy corresponding to the initial clusters of the eleventh round and subsequent rounds needs to be calculated.

[0072] When the current round number is less than or equal to ten rounds, first determine the round residual energy of the initial cluster in each round before the tenth round. The round residual energy is the node residual energy collected by the cluster head of the initial cluster from the member nodes of the local cluster. The cluster head accumulates the residual energy of these nodes to obtain the actual residual energy of the initial cluster. The actual residual energy is the round residual energy; then the cluster head of each initial cluster counts the query message broadcast by the base station, because each cluster head can receive the query message and the corresponding path every time the base station sends the query message, so it can count the weighted average query frequency of each cluster in the whole network, and determine the weighted average query frequency of the cluster set corresponding to the initial cluster in each round before the tenth round. The calculation formula is as follows:

[0073] p k =(x1*f1+x2*f2+…+x n *f n ) / n;

[0074] Where k is the time period from the current round number to less than or equal to ten rounds, p k is the weighted average query frequency of the cluster set in the kth round, n is the number of clusters in the cluster set to which the cluster needs to forward data, and f n is the number of times the node of the nth cluster in the cluster set is queried by the user, x n is the weight corresponding to the nth cluster in the cluster set, and the weight is the ratio of the frequency of data of the cluster being forwarded via the cluster to the frequency of data being sent by the cluster in the historical time round.

[0075] According to the round residual energy and weighted average query frequency, the cluster head of the initial cluster counts the weighted average query energy consumption of its corresponding cluster set. The calculation formula is as follows:

[0076] C=(E i-9 -E i ) / (p i +p i-1 +...+p i-9 )

[0077] Where C is the weighted average query energy consumption, E i-9 is the residual energy of the first round in the time period, E i is the remaining energy of the tenth round in the time period, p i ~p i-9 It is the weighted average query frequency of each round in the time period. The cluster set corresponding to the initial cluster includes the current cluster and the cluster to which the current cluster needs to forward data. The cluster to which the current cluster needs to forward data is the cluster to which the current cluster needs to forward data in the historical time round.

[0078] In the field of wireless sensor networks, the popular model for calculating the energy consumption of sensor nodes is as follows:

[0079] The transmission energy consumption of transmitting an L-bit message for d meters is:

[0080]

[0081] The energy consumption of a sensor node receiving an L-bit message is:

[0082] E R (L) = E elec L

[0083] Among them, E T (L,d) is the transmission energy consumption, E R (L) is the receiving energy consumption, L is the size of the data transmitted or received, d0 is the distance threshold between the two nodes of the data transmission, E elec The energy consumption of an electronic device to send or receive one bit of data, ∈ fs With ∈ mpare the energy consumption of free space propagation and multipath propagation, respectively.

[0084] During the operation of a specific clustering protocol, the energy consumption of a cluster in the wireless sensor network mainly includes the following aspects:

[0085] (1) The energy consumption of cluster heads receiving base station broadcast messages, such as user query messages, is calculated as follows:

[0086] E b =E elec L b

[0087] Among them, E b is the energy consumption of cluster head receiving the broadcast message of base station, E elec The energy consumption of an electronic device to send or receive one bit of data, L b The size of the broadcast message.

[0088] (2) The energy consumption of the cluster head collecting monitoring data of all nodes in the cluster, including the cluster head sending notification data to cluster member nodes and cluster member nodes sending monitoring data to the cluster head, is calculated as follows:

[0089]

[0090] Among them, E intra The cluster head collects the energy consumption of all nodes in the cluster, n c is the number of nodes in the cluster, i is the i-th node, p i is the frequency of data transmission by the i-th node in the current round, L i is the size of monitoring data sent by the i-th node, d intra is the average distance from the cluster node to the cluster head, L b2 is the size of the notification data sent by the cluster head to the member nodes, E elec The energy consumption of an electronic device to send or receive one bit of data, ∈ fs is the energy consumption for free space propagation.

[0091] (3) The energy consumption of the cluster in sending its own data and forwarding other clusters’ data is calculated as follows:

[0092]

[0093] E relay is the energy consumption of sending data of this cluster and forwarding data of other clusters, Q is the cluster set from which this cluster forwards data, n q is the number of nodes in the cluster set Q, j is the jth node, p j is the frequency of data transmission by the jth node in the cluster set in the current round, L jis the size of monitoring data sent by the i-th node in the cluster set, d inter is the distance between clusters in the cluster set, E elec The energy consumption of an electrical device to send or receive one bit of data, ∈ mp is the energy consumption of multipath propagation, n c is the number of nodes in this cluster, i is the i-th node in this cluster, p i is the frequency of data transmission by the i-th node in the cluster in the current round, L i The size of monitoring data sent by the i-th node in this cluster.

[0094] According to the above three energy consumption expressions of a cluster during the operation of the clustering protocol, it can be seen that E intra With E relay The value is proportional to the weighted average query frequency of the cluster set Q, while other parameters remain basically unchanged when the number of clusters remains unchanged. In addition, considering that there are more nodes in the cluster and the node monitoring data is larger than the query message broadcast by the base station, E relay +E intra Much larger than E b Therefore, when the network condition does not change significantly, the energy consumption of a cluster is proportional to the weighted average query frequency of its corresponding cluster set Q, that is, the prediction formula for the future cluster remaining energy can be determined based on the weighted average query frequency of the cluster set.

[0095] Then, based on the weighted average query energy consumption, the initial cluster calculates its predicted remaining energy when the current round number is greater than ten rounds, including:

[0096] According to the weighted average query energy consumption of the tenth round and the ten rounds before it, the initial cluster determines the prediction parameters of the weighted average query energy consumption of each future round based on the linear regression model of the least squares method. The calculation formula is as follows:

[0097]

[0098] Among them, k is the time period less than or equal to ten rounds from the current round, is the historical weighted average query energy consumption of each initial cluster in the kth round, and a and b are prediction parameters.

[0099] The initial cluster determines the remaining energy of the tenth round as the remaining energy of the final round. After determining the prediction parameters, it can construct a prediction formula for predicting the remaining energy of each future round. The principle of the prediction formula is that the predicted remaining energy of each future round is the final round remaining energy minus the predicted unit query energy consumption of each future round multiplied by the actual weighted query frequency. At the same time, the cluster head of this cluster sends the parameters of the prediction formula to the base station. The expression of the prediction formula is as follows:

[0100]

[0101] Where k is the time period from the current round number to less than or equal to ten rounds, C k is the weighted average query energy consumption predicted by each initial cluster in the kth round, A j is the predicted remaining energy of the cluster in round j (j>i), E i is the remaining energy of the tenth round in the time period, p k is the weighted average query frequency of the cluster set corresponding to this cluster in the kth round.

[0102] Based on the above prediction formula, the base station can obtain the predicted remaining energy of each cluster in the network in each round greater than 10 rounds without communicating with the clusters in the network, thereby reducing the energy consumption of nodes in the network due to communication.

[0103] Further, determining whether a prediction formula for predicting the predicted residual energy of the initial cluster needs to be updated, determining the actual residual energy of the initial cluster in each round when it is greater than ten rounds, the actual residual energy is the node residual energy received by the cluster head of the initial cluster from each member node, and determining the sum of the node residual energy of each member node as the actual residual energy of each cluster, and when the difference between the actual residual energy and the predicted residual energy is greater than a preset threshold, updating the prediction formula, including:

[0104] The final round residual energy is updated to the actual residual energy, that is, the final round residual energy is replaced by the actual residual energy of the latest round; the weighted average query energy consumption is recalculated according to the conditions of the current round and within ten rounds; the cluster head of the initial cluster determines the parameters of the new prediction formula according to the recalculated weighted average query energy consumption and the actual remaining energy, and sends the parameters to the base station; then the base station updates the outdated prediction formula according to the received new parameters. The updating process is the same as the process of constructing the prediction formula mentioned above, which will not be described in detail here.

[0105] After determining the location information and predicted remaining energy corresponding to the initial cluster, the shortest path and the total remaining energy are determined according to the location information and the predicted remaining energy, including:

[0106] Based on the Dijkstra algorithm (shortest path algorithm), the shortest path for each initial cluster to transmit monitoring data to the base station is determined; finally, the sum of the predicted remaining energies of each cluster in each shortest path is determined according to the predicted remaining energy of each initial cluster, and the sum of the predicted remaining energies is determined as the total remaining energy.

[0107] S3: The base station receives a user query message, and determines a cluster to be sent according to a target node of the user query message; the user query message is sent from the Internet to the base station, and the user query message includes which nodes the user needs to monitor data, namely the target nodes, so the base station determines the cluster to which the node to which the monitoring data required by the user belongs is located according to the target node of the user query message, and determines the cluster as the cluster to be sent; for example, if the target node of the monitoring data required by the user is node a1, and node a1 belongs to cluster A, then cluster A is determined as the cluster to be sent, and if the monitoring data required by the user includes multiple target nodes, and these multiple target nodes do not belong to the same cluster, then the clusters to which the multiple target nodes respectively belong are all determined as clusters to be sent; after the base station determines the cluster to be sent, the base station executes step S4.

[0108] S4: The base station calculates the forwarding efficiencies corresponding to the neighboring clusters of the to-be-transmitted cluster according to the cluster state information, and determines at most two to-be-transmitted clusters according to the forwarding efficiencies, including:

[0109] First, the base station averages the predicted residual energy of each initial cluster to obtain the average residual energy.

[0110] Next, the base station calculates the forwarding efficiency corresponding to the neighboring clusters of the to-be-sent cluster based on the decision basis, the predicted residual energy, the shortest path, the total residual energy, and the average residual energy. The decision basis is the formula for calculating the forwarding efficiency, as follows:

[0111]

[0112] Among them, H is the forwarding efficiency, E0 is the value of the predicted remaining energy, D is the value of the shortest path length, and E T is the total remaining energy value, E avg is the value of the average residual energy.

[0113] The cluster to be forwarded is determined according to the forwarding efficiency. Specifically, the neighbor clusters are sorted from large to small according to their corresponding forwarding efficiency, and at most two neighbor clusters are selected as the clusters to be forwarded based on the sorting results; when the number of neighbor clusters is greater than two, the top two neighbor clusters in the sorting results are used as the clusters to be forwarded; when the number of neighbor clusters is less than or equal to two, all neighbor clusters are used as clusters to be forwarded. Compared with the single path transmission method, the above multi-path transmission method can better achieve the balance of residual energy between clusters during the monitoring data transmission process.

[0114] S5: Repeat the above steps until a forwarding path is determined, where the forwarding path is a path for forwarding the monitoring data of the cluster to be sent to the base station, and the forwarding path includes the cluster to be forwarded that is forwarded multiple times, including:

[0115] Repeat steps S1 to S4 to determine the cluster to be forwarded each time forwarding. For example, the monitoring data of the cluster to be sent needs to be forwarded four times before it can be forwarded to the base station. Then steps S1 to S4 are to determine the cluster to be forwarded each time forwarding. Steps S1 to S4 need to be repeated four times to determine the forwarding path for the cluster to be sent to forward the monitoring data to the base station. The forwarding path is the complete path for the monitoring data of the cluster to be sent to be forwarded to the base station, including all clusters to be forwarded for four forwardings.

[0116] S6: The base station sends the forwarding path to the to-be-sent cluster, and the to-be-sent cluster and the to-be-forwarded cluster sequentially forward the monitoring data according to the forwarding path until the data reaches the base station, including:

[0117] First, the base station determines the sub-monitoring data to be forwarded by the cluster to be forwarded at each forwarding according to the forwarding path. The cluster to be sent sends the sub-monitoring data to the corresponding cluster to be forwarded respectively. The sub-monitoring data is the monitoring data divided according to the number of clusters to be forwarded at each forwarding and the forwarding efficiency.

[0118] In step S4, N clusters are determined as the clusters to be forwarded of the clusters to be sent each time forwarding, that is, the number of clusters to be forwarded corresponding to each sending cluster is N at each forwarding; in step S5, the complete forwarding path for the cluster to be sent to send the monitoring data to the base station is determined, the cluster head of the cluster to be sent receives the forwarding path sent by the base station, and the cluster to be sent divides the monitoring data into N sub-monitoring data to be forwarded by the cluster to be forwarded according to the path to be forwarded, and the size ratio of each sub-monitoring data is determined by the forwarding efficiency corresponding to each cluster to be forwarded; finally, the cluster to be sent sends the sub-monitoring data to the cluster to be forwarded corresponding to the sub-monitoring data, and repeats the above forwarding process according to the forwarding order of the forwarding path until the monitoring data is forwarded to the base station; the base station obtains the monitoring data based on the received sub-monitoring data to send the obtained monitoring data to the Internet, and the N mentioned above is less than or equal to 2, that is, there are at most 2 clusters to be forwarded in each forwarding process.

[0119] Next, the monitoring data forwarding method is further explained in combination with the specific implementation process, as follows: Assuming that the forwarding path includes two forwardings, the first forwarding includes two clusters to be forwarded, then the two clusters to be forwarded are Node1 and Node2, and the sub-monitoring data corresponding to each cluster to be forwarded are data1 and data2, and the forwarding efficiency corresponding to each cluster to be forwarded is H1 and H2; at this time, the size ratio of each sub-monitoring data data1 and data2 is H1:H2; then the cluster to be sent sends data1 to Node1 and sends data2 to Node2.

[0120] Assume that the two to-be-forwarded clusters forwarded for the first time have two corresponding to-be-forwarded clusters in the second forwarding. Then the to-be-forwarded cluster corresponding to cluster Node1 is Node 11、Node 12 , the cluster to be forwarded corresponding to cluster Node2 is Node 21 、Node 22 .

[0121] ClusterNode 11 、Node 12 The corresponding sub-monitoring data is obtained by dividing data1 into data 11 、data 12 , cluster Node 11 、Node 12 The forwarding efficiency is H 11 , H 12 , at this time the sub-monitoring data data 11 With data 12 The size ratio is H 11 :H 12 ; Cluster Node1 will data 11 Send to Node 11 , data 12 Send to Node 12 .

[0122] ClusterNode 21 、Node 22 The corresponding sub-monitoring data is obtained by dividing data2 into data 21 、data 22 , cluster Node 21 、Node 22 The corresponding forwarding efficiency is H 21 , H 22 ; At this time, the sub-monitoring data data 21 With data 22 The size ratio is H 21 :H 22 ; Cluster Node2 will data 21 Send to Node 21 , data 22 Send to Node 22 .

[0123] The last cluster Node 11 Node 12 Node 21 Node 22 Each of the received data 11 、data 12 、data 21 、data 22 Sent to the base station, the monitoring data forwarding is completed at this time.

[0124] The nodes in a wireless sensor network are usually distributed over a large area and have limited energy. Therefore, in the process of transmitting monitoring data between the cluster and the base station, multi-hop transmission is basically adopted. After all, nodes that are far away cannot communicate directly with the base station (i.e. single-hop communication). In the process of monitoring data transmission, the monitoring data is forwarded to the cluster with the highest forwarding efficiency, which can effectively disperse the load of monitoring data transmission, optimize energy consumption, and improve the balance of cluster energy.

[0125] The monitoring data forwarding method provided by the present invention comprehensively considers the cluster information of the entire network when determining the status information of each initial cluster, specifically comprehensively considers the positions of the clusters of the entire network to obtain the shortest path, and then obtains the total residual energy in the status information according to the residual energy of the clusters passed by the shortest path, thereby achieving the acquisition of the global optimal forwarding path. Compared with the currently developed monitoring data forwarding method, which only considers the neighbor cluster status (residual energy) of the cluster to be sent, but does not consider the status information of the clusters that are farther away but may be related, such as the residual energy of the clusters passed when sending data, this is easy to form a local optimal rather than a global optimal situation. Therefore, by considering the information of the clusters passed by all possible forwarding paths, the global optimal forwarding path can be obtained. In addition, the monitoring data is transmitted by multiple paths to avoid the related nodes in the forwarding path from consuming too much energy due to the transmission of the monitoring data by a single path, which makes the energy consumption of each cluster in the network more balanced while reducing the energy consumption of the cluster.

[0126] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for forwarding monitoring data in a wireless sensor network, characterized in that: The wireless sensor network includes a plurality of sensor nodes; the monitoring data forwarding method includes: Dividing a plurality of sensor nodes of the wireless sensor network into a plurality of initial clusters; The base station maintains the cluster state information of the initial cluster through a cluster state maintenance algorithm based on a prediction mechanism; The base station receives a user query message, and determines a cluster to be sent according to a target node of the user query message; The base station calculates forwarding efficiencies corresponding to neighboring clusters of the to-be-transmitted cluster based on the decision basis and according to the cluster state information, and determines at most two to-be-transmitted clusters based on the forwarding efficiencies; Repeat the above steps until a forwarding path is determined, where the forwarding path is a path for forwarding the monitoring data of the to-be-sent cluster to the base station, and the forwarding path includes the to-be-sent cluster that is forwarded multiple times; The base station sends the forwarding path to the to-be-sent cluster, and the to-be-sent cluster and the to-be-forwarded cluster sequentially forward the monitoring data according to the forwarding path until the monitoring data reaches the base station.

2. A wireless sensor network monitoring data forwarding method according to claim 1, characterized in that: The cluster state information includes the location information of the initial cluster, the predicted remaining energy, the shortest path and the total remaining energy; the base station maintains the cluster state information of the initial cluster through a cluster state maintenance algorithm based on a prediction mechanism, including: The cluster head of the initial cluster determines the centroid coordinates of the initial cluster and sends them to the base station; The base station determines the centroid coordinates as the location information; The base station determines the predicted remaining energy according to the current round number; The base station determines the shortest path and the total remaining energy according to the location information and the predicted remaining energy.

3. A wireless sensor network monitoring data forwarding method according to claim 2, characterized in that: The base station determines the predicted remaining energy according to the current round number, including: When the current round number is less than or equal to ten rounds, not predicting the predicted remaining energy corresponding to the initial cluster; When the current round number is greater than ten rounds, the cluster head of the initial cluster performs statistics on the weighted average query energy consumption of its corresponding cluster set; the cluster set includes the current cluster and the cluster to which the current cluster needs to forward data; the cluster to which the current cluster needs to forward data is the cluster to which the current cluster needs to forward data in the historical time round; According to the weighted average query energy consumption, the initial cluster calculates its predicted remaining energy when the current round number is greater than ten rounds.

4. A wireless sensor network monitoring data forwarding method according to claim 3, characterized in that: When the current round number is greater than ten rounds, the cluster head of the initial cluster performs statistics on the weighted average query energy consumption of its corresponding cluster set, including: When it is determined that the initial cluster is less than or equal to ten rounds, the cluster head records the round residual energy of each round and the weighted average query frequency of its corresponding cluster set, which is calculated as follows: p k =(x1*f1+x2*f2+…+x n *f n ) / n; Where k is the time period from the current round number to less than or equal to ten rounds, p k is the weighted average query frequency of the cluster set in the kth round, n is the number of clusters in the cluster set to which the cluster needs to forward data, and f n is the number of times the node of the nth cluster in the cluster set is queried by the user, x n is the weight corresponding to the nth cluster in the cluster set, and the weight is the ratio of the frequency of data of this cluster being forwarded by this cluster to the frequency of data being sent by this cluster in the historical time round; According to the round residual energy and the weighted average query frequency, the cluster head of the initial cluster calculates the weighted average query energy consumption of its corresponding cluster set, and the calculation formula is as follows: C=(E i-9 -E i ) / (p i +p i-1 +...+p i-9 ) Where C is the weighted average query energy consumption, E i-9 is the residual energy of the first round in the time period, E i is the remaining energy of the tenth round in the time period, p i ~p i-9 It is the weighted average query frequency of each round within the time period.

5. A wireless sensor network monitoring data forwarding method according to claim 4, characterized in that: The initial cluster calculates its predicted remaining energy according to the weighted average query energy consumption when the current round number is greater than ten rounds, including: determining a final round residual energy of the initial cluster in a tenth round within a time period; According to the weighted average query energy consumption of the ten historical rounds, the prediction parameters of the linear regression model based on the least squares method are determined, and the calculation formula is as follows: Where k is the time period from the current round number to less than or equal to ten rounds, C k is the historical weighted average query energy consumption of each initial cluster in the kth round, a and b are prediction parameters; A prediction formula is constructed based on the final round remaining energy and the calculated prediction parameters, and its expression is as follows: Where k is the time period from the current round number to less than or equal to ten rounds, C k is the weighted average query energy consumption predicted by each initial cluster in the kth round, A j is the predicted remaining energy of the cluster in round j (j>i), E i is the remaining energy of the tenth round in the time period, p k is the weighted average query frequency of the cluster set corresponding to this cluster in the kth round; The cluster head of the initial cluster calculates the predicted residual energy of each future round through the prediction formula.

6. A wireless sensor network monitoring data forwarding method according to claim 5, characterized in that: The cluster head of the initial cluster receives the node residual energy of each member node, and determines the sum of the node residual energy of each member node as the actual residual energy of each cluster; When the difference between the actual remaining energy and the predicted remaining energy is greater than a preset threshold, updating the prediction formula includes: Updating the final round remaining energy to the actual remaining energy of the current round; The cluster head of the initial cluster determines a new prediction parameter according to the weighted average query energy consumption and the actual remaining energy of the current round, and sends the actual remaining energy of the current round and the new prediction parameter to the base station; The base station updates the prediction formula according to the received actual remaining energy of the corresponding cluster in the current round and the new prediction parameter.

7. A wireless sensor network monitoring data forwarding method according to claim 2, characterized in that: The base station determines the shortest path and the total remaining energy according to the location information and the predicted remaining energy, including: Determine the shortest path according to the location information, where the shortest path is a path from the initial cluster to the base station passing through the least number of clusters; The total remaining energy is determined according to the predicted remaining energy and the shortest path, where the total remaining energy is the sum of the predicted remaining energies from the initial cluster to the clusters passed by the base station.

8. A wireless sensor network monitoring data forwarding method according to claim 2, characterized in that: The base station calculates forwarding efficiencies corresponding to neighboring clusters of the to-be-transmitted cluster based on the decision basis and according to the cluster state information, and determines at most two to-be-transmitted clusters based on the forwarding efficiencies, including: determining an average residual energy of a plurality of initial clusters of the wireless sensor network; Based on the predicted residual energy, the shortest path, the total residual energy and the average residual energy, calculating the forwarding efficiencies corresponding to the neighboring clusters of the to-be-sent cluster respectively; The neighbor clusters are sorted from large to small according to their corresponding forwarding efficiencies; When the number of the neighbor clusters is greater than two, selecting the first two neighbor clusters in the ranking as the to-be-forwarded clusters; When the number of the neighbor clusters is less than or equal to two, all neighbor clusters are selected as the clusters to be forwarded.

9. A wireless sensor network monitoring data forwarding method according to claim 7, characterized in that: The base station sends the forwarding path to the to-be-sent cluster, and the to-be-sent cluster and the to-be-forwarded cluster sequentially forward the monitoring data according to the forwarding path until the monitoring data reaches the base station, including: The base station determines the sub-monitoring data to be forwarded by the cluster to be forwarded each time according to the forwarding path; The cluster to be sent sends the sub-monitoring data to the corresponding cluster to be forwarded respectively, wherein the sub-monitoring data is obtained by dividing the monitoring data according to the number of clusters to be forwarded and the forwarding efficiency at each forwarding; The above steps are repeated according to the forwarding order of the forwarding path until the monitoring data is forwarded to the base station.

10. A wireless sensor network monitoring data forwarding method according to claim 8, characterized in that: The decision-making basis is the formula for calculating the forwarding efficiency, which is as follows: Among them, H is the forwarding efficiency, E0 is the value of the predicted remaining energy, D is the value of the shortest path length, and E T is the total remaining energy value, E avg The value of the average residual energy.

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