Energy cooperation method based on lending and returning mechanism under demand diffusion

Abstract

The present application relates to a kind of energy cooperation method based on lending mechanism under demand diffusion, belong to energy cooperation communication field.The method includes: S1: demand diffusion: when the energy deficient node own energy cannot satisfy the minimum energy consumption of data packet transmission, utilize the energy that has had to the outside release energy demand information, nearby received information node help to diffuse and form energy cooperation set;S2: the determination of energy cooperation node: in energy cooperation set, using lending mechanism, the priority of energy cooperation node is determined, and energy cooperation node is selected;S3: energy cooperation: each selected energy cooperation node transmits power to energy deficient node according to certain principle, realizes the energy cooperation between nodes.The present application makes full use of node broadcast characteristics and lending mechanism to realize the energy cooperation between nodes, prolongs network life cycle, and improves data packet transmission reliability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of energy cooperation communication, and relates to an energy cooperation method based on a lending and returning mechanism under demand diffusion. BACKGROUND

[0002] In a wireless sensor network, energy has been an important factor restricting its development. In order to further prolong the life cycle of nodes and the network, on the one hand, various transmission methods for reducing the energy consumption of nodes are adopted, such as sleep scheduling, cooperative transmission, network clustering. On the other hand, different renewable energy collection schemes, power distribution methods and the like are successively proposed to provide a sustainable energy and power distribution scheme for nodes in the wireless sensor network. Once the traditional battery-powered node runs out of energy, it will be unable to continue to undertake the monitoring and data packet transmission tasks, and the emergence of energy collection becomes another solution to the energy problem. Energy collection provides sustainable energy for nodes and ensures the efficient and reliable operation of the network. Energy collection is a hot research issue at present and is also a trend of the continuous development of the wireless sensor network.

[0003] In an energy collection wireless sensor network, the positions of nodes are fixed, and some nodes collect less energy due to the positions and the like, and some nodes collect excessive energy, so that the energy collection of the entire network presents an unbalanced state. When the energy of an energy-deficient node in the network cannot meet the minimum energy consumption for data packet transmission, energy cooperation is needed. In the current research on energy collection networks, most of the energy cooperation research cannot effectively solve the problem of energy-deficient nodes. Therefore, the broadcast characteristics of nodes are utilized to carry out research on a demand diffusion type energy cooperation method. On the other hand, in order to standardize the energy cooperation behavior of nodes, a lending and returning mechanism is introduced to determine the priority of nodes in an energy cooperation set and select energy cooperation nodes. Finally, the selected energy cooperation nodes transmit power to energy-deficient nodes according to certain principles, so as to realize energy cooperation between nodes.

[0004] The present application is directed to an energy collection wireless sensor network, fully utilizes the broadcast characteristics of nodes to realize demand diffusion type energy cooperation of energy-deficient nodes. At the same time, in order to standardize the energy cooperation behavior of nodes, a lending and returning mechanism is introduced to determine the priority of nodes in an energy cooperation set and select energy cooperation nodes. Finally, the selected energy cooperation nodes transfer their energy to energy-deficient nodes in the form of radio frequency signals, further prolong the life cycle of the network and improve the reliability of data packet transmission of nodes. SUMMARY

[0005] In view of the above, the present application aims to provide an energy cooperation method based on lending and borrowing mechanism under demand diffusion. The energy demand signal is broadcasted by the energy deficient node and diffused by the optimal forwarding node, forming an energy cooperation set of the energy deficient node. The priority of the nodes in the energy cooperation set is determined by using the lending and borrowing mechanism, and the energy cooperation nodes are selected. The selected energy cooperation nodes transmit power to the energy deficient nodes according to certain principles, and the energy cooperation between the nodes is completed.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] An energy cooperation method based on lending and borrowing mechanism under demand diffusion, comprising the following steps:

[0008] S1: demand diffusion; sensing node S κ Before sending data, it is judged whether the energy of the sensing node S itself meets the minimum energy requirement for data packet transmission. If the energy of the sensing node S itself is greater than or equal to the required energy, the sensing node S directly sends the data packet to the sink node D; otherwise, the sensing node S broadcasts the energy demand signal to the surrounding nodes.

[0009] S2: determination of the energy cooperation set; received sensing node S κ The nodes that receive the energy demand signal form a cooperation set P1, and the cooperation set P1 meets the energy demand condition of the sensing node S κ The nodes that meet the energy demand condition form an energy cooperation set N1. If the energy cooperation set N1 is not empty, the energy cooperation based on the lending and borrowing mechanism is realized in the energy cooperation set N1. If the energy cooperation set N1 is empty, the nodes in the cooperation set P1 compete to become the optimal forwarding node S r according to the distance and energy value factors, and the energy demand signal of the sensing node S κ is diffused until there is no node in the network that can meet the energy demand condition of the sensing node S κ , and an event interruption is triggered.

[0010] S3: energy cooperation based on the lending and borrowing mechanism; in the energy cooperation set, the priority of the nodes in the energy cooperation set is determined according to whether the nodes have participated in the energy cooperation and the energy value when the energy cooperation is performed, and the energy cooperation nodes are selected; each selected energy cooperation node transmits power to the sensing node S κ according to certain principles, and the energy cooperation between the nodes is realized.

[0011] Further, in the S2, the formation of the energy cooperation set N1 is as follows:

[0012] (1) When the energy of the sensing node S κ itself is less than the required energy, the sensing node S κThe nodes that send ED frames form a cooperative set P1; the nodes in cooperative set P1 calculate the distance to S based on the received signals. κ The maximum distance allowed when the minimum energy required to transfer it is:

[0013]

[0014] Where node S p1 Let P1 be any node in the collaboration set; is the energy conversion efficiency; m is the channel fading coefficient between nodes; T is the energy cooperation time; For node S p1 The power at which energy is emitted; For the current time slot sensing node S κ Data packet transmission energy consumption; For the previous time slot sensing node S κ The remaining energy value; For the current time slot sensing node S κ The amount of energy collected; For sensor node S κ Energy consumption during broadcast ED frames; For node S p1 and sensor node S κ Inter-channel value;

[0015] (2) S p1 With S κ actual distance and In comparison, if Less than Then node S p1 Add to the energy cooperation set N1, and to the cooperation set P1 and S p1 Nodes with similar conditions eventually form sensing node S. κ The energy cooperation set N1.

[0016] Furthermore, in S2, the optimal forwarding node S r Determination: When the energy cooperation set N1 is empty, nodes in the cooperation set P1 start timers and set their respective timer initial values; the node with the smallest initial timer value eventually competes to become the best forwarding node S. r S r Diffusion sensor node S κ Energy demand signal; initial values ​​satisfy:

[0017]

[0018] in For sensor node S κ Minimum energy requirement; For any node S p1 To the sensor node S κ The energy value of energy cooperation; For any node S p1 The actual distance between the sensor node S κ .

[0019] The optimal forwarding node S r After determination, diffuse the energy requirement signal of the sensor node S κ , stop until no node in the network can meet the energy requirement condition of the sensor node S κ , and trigger the event interruption.

[0020] Further, in S3, energy cooperation based on lending and borrowing mechanism: when the arbitrary energy cooperation set is not empty, determine the priority of the nodes in the energy cooperation set according to whether the nodes have participated in energy cooperation and the energy value at the time of energy cooperation, and select the energy cooperation node; for convenience of description, the arbitrary energy cooperation set will be referred to as the energy cooperation set below. The energy cooperation list is the set of the remaining nodes that have realized energy cooperation with the energy deficient node in the previous time slot; the energy value table is the set of energy values of the energy cooperation between the nodes in the previous time slot; for any node in the energy cooperation set, if the energy cooperation list of the node contains the sensor node S κ , a lending and borrowing set is formed, otherwise a non-lending and borrowing set is formed; the priority of the nodes in the energy cooperation set and the selected energy cooperation node are described as follows:

[0021] (1) If the lending and borrowing set is empty, it indicates that the sensor node S κ has not realized energy cooperation with any node in the energy cooperation set in the previous time slot; at this time, the nodes in the non-lending and borrowing set have the same priority, and part of the nodes are selected as the energy cooperation nodes, transmit the power to the sensor node S κ according to the energy borrowing mode; after energy cooperation, the sensor node S κ realizes data packet transmission; the nodes involved in the energy cooperation process update their own energy cooperation list and energy value table.

[0022] (2) When the lending and borrowing set is not empty, it indicates that the sensor node S κ has realized energy cooperation with some nodes in the energy cooperation set in the previous time slot. The nodes in the lending and borrowing set query their own energy value table to obtain the energy value of the previous cooperation with the sensor node S κ . Wherein any node S j (j = 1, 2 …… J) in the lending and borrowing set, J is the number of nodes in the lending and borrowing set. The energy value of the previous cooperation of any node S j with the sensor node S κ is denoted as The energy value of the previous cooperation of any node S jThe existing energy is denoted as Its value is:

[0023]

[0024] In the formula For any node S in the previous time slot j The remaining energy; For any node S in the current time slot j The amount of energy collected;

[0025] a. If the energy values ​​of each node in the borrowing and returning set satisfy... and If the nodes in the borrowing and returning set have the same priority and are all selected energy cooperation nodes, they will return energy to the sensing node S according to the energy return method. κ Transfer energy.

[0026] b. If the energy values ​​of each node in the borrowing and returning set satisfy... but in The nodes with high priority and all being selected energy cooperation nodes return energy to the sensing node S according to the energy return method. κ Energy transfer. The remaining nodes in the borrowing and returning set have lower priority; some of these nodes are selected as energy cooperation nodes and transfer energy to sensor node S according to the borrowing method. κ Transfer energy.

[0027] c. If the energy values ​​of each node in the borrowing and returning set satisfy... Furthermore, the borrowing and returning set is not empty. Nodes in the borrowing and returning set have high priority and are all selected energy cooperation nodes, returning energy to sensor node S according to the energy return method. κ Energy transfer. Nodes in the non-borrowing / returning set have low priority; some of these nodes are selected as energy cooperation nodes and transfer energy to sensor node S according to the energy borrowing method. κ Transfer energy.

[0028] d. If the energy values ​​of each node in the borrowing and returning set satisfy... However, the non-borrowing and returning set is empty. Nodes in the borrowing and returning set have the same priority, and some nodes are selected as energy cooperation nodes, borrowing energy from sensor node S according to the energy borrowing method. κ Transfer energy.

[0029] After energy collaboration, sensor node S κ Data transmission is achieved. During the energy collaboration process, the nodes involved update their respective energy collaboration lists and energy value tables.

[0030] Furthermore, in step S3, each selected energy cooperation node sends a signal to the sensing node S according to certain principles. κ Transmission power;

[0031] (1) Energy return: The selected energy cooperation nodes in the borrowing and returning set eventually return energy to the sensing node S. κ The energy transferred is equal to the energy previously obtained from it. At this point, any node in the borrowing and returning set is denoted as S. br The energy it consumes is:

[0032]

[0033] In the formula For node S br Previously from sensor node S κ The energy value obtained at the location; is the energy conversion efficiency; m is the inter-node channel fading coefficient; T is the energy cooperation time; For node S br and sensor node S κ Inter-channel value; For node S br and sensor node S κ The actual distance between them.

[0034] (2) Energy borrowing:

[0035] 1. Due to the diffusion of energy demand signals, the optimal forwarding node S r Diffusion sensor node S κ ED frames require a certain amount of energy, and are therefore considered as sensor node S. κ Borrow the best forwarding node S r The energy is used to propagate the energy demand signal. Optimal forwarding node S r The energy consumed by the diffusion of the ED frame is recorded in the sensing node S. κ The list of energy collaborations and the energy value table.

[0036] 2. Nodes in either the borrowing / returning set or the non-borrowing / returning set eventually communicate with sensor node S. κ The total energy transferred is equal to the energy transferred at sensor node S. κ of At this point, the number of nodes in the borrowing / returning set or the non-borrowing / returning set will affect the sensor node's status. The allocation.

[0037] a. If there is one and only one node in the energy cooperation set, regardless of whether that node belongs to the borrowing / returning set or the non-borrowing / returning set, then that node is selected as the sensing node S. κ The energy cooperation node is denoted as S. select The energy it consumes is:

[0038]

[0039] b. If there are multiple nodes in the energy cooperation set, and these nodes belong to both the borrowing and returning set and the non-borrowing and returning set, then to reduce the energy cooperation burden on individual nodes in each set while ensuring the reliability of data transmission within each set, it is necessary to rationally allocate the energy from each set's nodes to the sensing node S. κ The transferred energy value. Therefore, sensor nodes S are assigned to each set of nodes. κ of The problem is represented as follows, where any node in each set is denoted as S. f :

[0040]

[0041] β f ∈(0,1]

[0042] F > 1

[0043]

[0044] In the formula, F represents the number of nodes in the energy cooperation set; β f Power allocation factor; For node S f Energy consumption value of broadcast ED frames.

[0045] As can be seen from the formula, this problem is a convex optimization problem. This problem can be solved using an improved directional water injection algorithm, namely... Less data is allocated to nodes with good channel conditions in the aggregation node D, and more data is allocated to nodes with poor channel conditions in the aggregation node D. This ensures the performance of sensor node S. κ Finally obtained This does not affect the data transmission reliability of other nodes. An improved directional water injection algorithm is used to determine the power allocation factor of each node, and nodes with a power allocation factor other than 1 are selected as energy cooperation nodes. Then, the energy cooperation nodes transmit data to the sensing node S. κ Transfer the corresponding energy value. Sensor node S κ After receiving energy, data transmission is completed, and each node updates its own energy collaboration list and energy value table.

[0046] The beneficial effects of this invention are as follows:

[0047] (1) Based on the characteristics of energy collection differences among nodes in an energy harvesting network, this invention proposes a method for disseminating energy demand signals. By broadcasting and disseminating the energy demand signals, an energy cooperation set of energy-deficient nodes is formed. Finally, the nodes in the energy cooperation set transfer energy to the energy-deficient nodes in the form of radio frequency to help them complete the transmission of data packets.

[0048] (2) The application selects the optimal forwarding node of the diffusion energy demand signal according to the energy difference and distance between nodes, and helps the energy deficient node to diffuse the energy demand signal to find the energy cooperation node.

[0049] (3) The application standardizes the energy cooperation behavior of the node, introduces the lending and borrowing mechanism, determines the priority of the node in the energy cooperation set, selects the energy cooperation node, and transmits power to the energy deficient node according to certain principles, so as to complete the energy cooperation between nodes.

[0050] (4) The application fully utilizes the broadcast characteristics of the node in the network and the energy cooperation of the lending and borrowing mechanism, prolongs the life cycle of the network, and improves the data packet transmission reliability of the node.

[0051] Other advantages, objects and features of the application will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following specification or can be learned by practice of the application. The objects and other advantages of the application can be realized and attained by the methods and instrumentalities particularly pointed out in the written description and claims. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to make the objects, technical solutions and advantages of the application clearer, the preferred detailed description of the application will be combined with the drawings to describe the application, and the drawings are as follows:

[0053] Figure 1 The system model of the application;

[0054] Figure 2 The communication flow chart of the energy cooperation method based on the lending and borrowing mechanism under the requirement diffusion described in the application; (a) the sensing node S κ sends the data packet directly to the sink node D; (b) the sensing node S κ broadcasts the ED frame, the formation of the cooperation set P1 and the formation of the energy cooperation set N1 when the energy of the sensing node S is less than the required energy; (c) the optimal forwarding node S r diffuses the ED frame, and the formation of the remaining cooperation set; (d) the formation of the remaining energy cooperation set under the ED frame diffusion; (e) the energy cooperation condition when the lending and borrowing set is empty; (f) the energy cooperation condition when the lending and borrowing set is not empty, the energy value satisfies and the energy cooperation condition when the lending and borrowing set is not empty, the energy value satisfies but the energy cooperation condition when the lending and borrowing set is not empty, the energy value satisfies and the non-lending and borrowing set is not empty; (I) the energy cooperation condition when the lending and borrowing set is not empty, the energy value satisfies but the non-lending and borrowing set is empty. Detailed Implementation

[0055] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0056] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0057] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0058] like Figure 1 As shown, this invention presents a system model of an energy cooperation method based on a borrowing and returning mechanism under demand diffusion in an energy harvesting network. The system model considered in this invention consists of K sensing nodes S κ A wireless sensor network consisting of (κ=1,2……K) and a sink node D. The channel between any two nodes in the system follows quasi-static Rayleigh fading and is independent of each other. The instantaneous channel gain between each sensor node is expressed as... The instantaneous channel gain between each sensing node and the aggregation node D is In the Rayleigh fading model, the square of the instantaneous channel gain follows an exponential distribution. and They are respectively and The exponential random variables have variances of respectively and Assume all channels in the system are equivalent and invertible, i.e. Furthermore, all instantaneous channel gains remain constant during each round of data packet transmission. The system provides a signal with a mean of 0 and a variance of [missing value] around the receiver during data transmission. Given additive white Gaussian noise, and setting the data packet transmission power of the sensor node to P, the average signal-to-noise ratio between nodes is: Each node is equipped with a single antenna and operates in half-duplex mode. The information transmission rate per unit spectrum between nodes is Ωbps.

[0059] All sensor nodes are equipped with solar energy harvesting devices, high-capacity rechargeable batteries, and independent radio frequency transceiver modules. Sensor nodes can harvest energy using solar energy harvesting devices and store the harvested energy for subsequent information transmission. They can also transfer / acquire energy to / from other nodes during energy cooperation using their radio frequency transceiver modules. An Energy Deficiency (ED) frame is an energy demand signal for nodes with fewer energy harvesting nodes, containing their node number and minimum energy demand value. Any node can use the ED frame to learn about the channel state and node location information between two nodes and calculate the distance between them.

[0060] like Figure 2 The diagram shown is a communication flowchart of an energy cooperation method based on a borrowing and returning mechanism under demand diffusion in an energy harvesting network according to the present invention. The specific steps are as follows:

[0061] 1. Sensor node S κ Before sending data, it checks if its own energy meets the minimum energy consumption for data packet transmission. If its own energy is greater than or equal to the required energy, it directly sends the data packet to the aggregation node D. Figure 2 As shown in (a).

[0062] 2. If sensor node S κ If its own energy is less than the required energy, it broadcasts an energy demand signal to the surroundings, such as... Figure 2 As shown in (b). The sensor node S receives the data. κ The nodes that send ED frames form a cooperative set P1; the nodes in cooperative set P1 calculate the distance to S based on the received signals. κ The maximum distance allowed when the minimum energy required to transfer it is:

[0063]

[0064] Where node S p1 Let P1 be any node in the collaboration set; is the energy conversion efficiency; m is the channel fading coefficient between nodes; T is the energy cooperation time; For node S p1 The power at which energy is emitted; For the current time slot sensing node Sκ Data packet transmission energy consumption; For the previous time slot sensing node S κ The remaining energy value; For the current time slot sensing node S κ The amount of energy collected; For sensor node S κ Energy consumption during broadcast ED frames; For node S p1 and sensor node S κ Inter-channel values;

[0065] (2) S p1 With S κ actual distance and In comparison, if Less than Then node S p1 Add to the energy cooperation set N1, and to the cooperation set P1 and S p1 Nodes with similar conditions eventually form sensing node S. κ The energy cooperation set N1.

[0066] 3. When the energy cooperation set N1 is empty, the nodes in the cooperation set P1 start timers and set their respective timer initial values; the node with the smallest initial timer value eventually competes to become the best forwarding node S. r S r Diffusion sensor node S κ Energy demand signal; initial values ​​satisfy:

[0067]

[0068] in For sensor node S κ Minimum energy requirement; Let S be any node in set P1 within time T. p1 To sensor node S κ The energy value for energy collaboration; For any node S p1 With sensor node S κ The actual distance between them.

[0069] Best forwarding node S r Once determined, the diffusion sensing node S κ Energy demand signals, such as Figure 2 As shown in (c). This continues until the remaining cooperation sets and energy cooperation sets are formed, as shown in [c]. Figure 2 As shown in (d). When no node in the network can satisfy the sensor node S κ When the energy demand condition is met, the event stops, triggering an interruption.

[0070] 4. When any energy cooperation set is not empty, the priority of nodes in the energy cooperation set is determined according to whether nodes have participated in energy cooperation and the energy value at the time of cooperation, and energy cooperation nodes are selected. For ease of description, any energy cooperation set will be referred to as the energy cooperation set below. The energy cooperation list is the set of other nodes that have previously cooperated with a certain energy-deficient node in a time slot; the energy value table is the set of energy values ​​from previous time slot energy cooperation between nodes; for any node in the energy cooperation set, if the node's energy cooperation list contains sensor node S... κ If a node is selected, a borrowing and returning set is formed; otherwise, a non-borrowing and returning set is formed. The priority of nodes in the energy cooperation set and the selection of energy cooperation nodes are described as follows:

[0071] (1) If the borrowing and returning set is empty, it means that the sensor node S in the previous time slot is empty. κ Energy cooperation was not achieved with any node in the energy cooperation set; at this time, nodes in the non-borrowing and returning set have the same priority, and some nodes are selected as energy cooperation nodes, borrowing energy from sensor node S according to the energy borrowing method. κ Transmission power, such as Figure 2 As shown in (e); after energy cooperation, the sensing node S κ Enables data packet transmission; during the energy collaboration process, the nodes involved update their respective energy collaboration lists and energy value tables.

[0072] (2) When the borrowing and returning set is not empty, it indicates that the sensor node S in the previous time slot is empty. κ Energy cooperation has been implemented with some nodes in the energy cooperation set. Nodes in the borrowing and returning set query their respective energy value tables to retrieve previous data from sensor node S. κ The energy value of collaboration. Any node in the borrowing and returning set is denoted as S. j (j = 1, 2, ..., J), where J is the number of nodes in the borrowing and returning set. Any node S... j Previously with sensor node S κ The energy value of collaboration is denoted as Any node S j The existing energy is denoted as Its value is:

[0073]

[0074] In the formula For any node S in the previous time slot j The remaining energy; For any node S in the current time slot j The amount of energy collected;

[0075] a. If the energy values ​​of each node in the borrowing and returning set satisfy... and If the nodes in the borrowing and returning set have the same priority and are all selected energy cooperation nodes, they will return energy to the sensing node S according to the energy return method. κ Transfer of energy, such as Figure 2 As shown in (f).

[0076] b. If the energy values ​​of each node in the borrowing and returning set satisfy... but in The nodes with high priority and all being selected energy cooperation nodes return energy to the sensing node S according to the energy return method. κ Energy transfer. The remaining nodes in the borrowing and returning set have lower priority; some of these nodes are selected as energy cooperation nodes and transfer energy to sensor node S according to the borrowing method. κ Transfer of energy, such as Figure 2 As shown in (g).

[0077] c. If the energy values ​​of each node in the borrowing and returning set satisfy... Furthermore, the borrowing and returning set is not empty. Nodes in the borrowing and returning set have high priority and are all selected energy cooperation nodes, returning energy to sensor node S according to the energy return method. κ Energy transfer. Nodes in the non-borrowing / returning set have low priority; some of these nodes are selected as energy cooperation nodes and transfer energy to sensor node S according to the energy borrowing method. κ Transfer of energy, such as Figure 2 As shown in (h).

[0078] d. If the energy values ​​of each node in the borrowing and returning set satisfy... However, the non-borrowing and returning set is empty. Nodes in the borrowing and returning set have the same priority, and some nodes are selected as energy cooperation nodes, borrowing energy from sensor node S according to the energy borrowing method. κ Transfer of energy, such as Figure 2 As shown in (I).

[0079] After energy collaboration, sensor node S κ Data transmission is achieved. During the energy collaboration process, the nodes involved update their respective energy collaboration lists and energy value tables.

[0080] Furthermore, in step S3, each selected energy cooperation node sends a signal to the sensing node S according to certain principles. κ Transmission power;

[0081] (1) Energy return: The selected energy cooperation nodes in the borrowing and returning set eventually return energy to the sensing node S. κ The energy transferred is equal to the energy previously obtained from it. At this point, any node in the borrowing and returning set is denoted as S. br The energy it consumes is:

[0082]

[0083] where is the node S br acquired energy value from the sensor node S κ ; is the energy conversion efficiency; m is the inter-node channel fading coefficient; T is the energy cooperation time; is the node S br and the sensor node S κ channel value; is the actual distance between the node S br and the sensor node S κ .

[0084] (2) Energy borrowing:

[0085] 1. Since the optimal forwarding node S r spreads the sensor node S κ ED frame, it consumes certain energy, and at this time the sensor node S κ borrows the energy of the optimal forwarding node S r to spread the energy demand signal. The optimal forwarding node S r and the energy value consumed by its spread ED frame are recorded in the energy cooperation list and the energy value table of the sensor node S κ .

[0086] 2. The total energy transferred by the nodes in the borrowing and returning set or the non-borrowing and returning set to the sensor node S κ is equal to the κ of the sensor node S κ . At this time, the number of nodes in the borrowing and returning set or the non-borrowing and returning set will affect the allocation of each node to the sensor node .

[0087] a. If there is only one node in the energy cooperation set, regardless of whether the node belongs to the borrowing and returning set or the non-borrowing and returning set, the node is selected as the energy cooperation node of the sensor node S select , denoted as S κ . The energy consumed by it is:

[0088]

[0089] b. If there are multiple nodes in the energy cooperation set and these nodes belong to the borrowing and returning set and the non-borrowing and returning set respectively. In order to reduce the energy cooperation burden of individual nodes in each set and at the same time guarantee the reliability of data transmission of nodes in each set, it is necessary to reasonably allocate the energy value transferred by the nodes in each set to the sensor node S κ . Therefore, the nodes in each set allocate the E min_Sκ of the sensor node S f (i) The problem is represented as follows, where any node in each set is denoted as Sf :

[0090]

[0091] β f ∈(0,1]

[0092] F>1

[0093]

[0094] In the formula, F is the number of nodes in the energy cooperation set; β f is the power allocation factor; is the node S f broadcasts the energy consumption value of the ED frame.

[0095] In the formula, it is known that the problem is a convex optimization problem. The improved directional water injection algorithm can be used to solve the problem, i.e. the nodes with good channel conditions for the sink node D are allocated less, and the nodes with poor channel conditions for the sink node D are allocated more. The data transmission reliability of the remaining nodes is not affected while the energy of the sensor node S κ is finally obtained. Through the improved directional water injection algorithm, the power allocation factor of each node is determined, and the node with the power allocation factor not being 1 is selected as the energy cooperation node. Then the energy cooperation node transfers the corresponding energy value to the sensor node S κ . After receiving the energy, the sensor node S κ completes the data transmission, and each node updates the energy cooperation list and the energy value table.

[0096] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the purpose and scope of the technical solutions, which should be covered in the scope of the claims of the present application.

Claims

1. An energy cooperation method based on lending and borrowing mechanism under demand diffusion, characterized in that: The method comprises the following steps: S1: demand diffusion; sensor node S κ Before sending data, it is determined whether the energy of the sensor node S meets the minimum energy requirement for data packet transmission. If the energy of the sensor node S is greater than or equal to the required energy, the sensor node S directly sends the data packet to the sink node D. Otherwise, the sensor node S broadcasts an energy requirement signal to the surrounding sensor nodes. S2: determination of energy cooperation set; received sensor node S κ The nodes that send energy demand signals form a cooperation set P1, and the cooperation set P1 meets the energy demand conditions of the sensor node S κ The nodes that meet the energy demand conditions form an energy cooperation set N1; if the energy cooperation set N1 is not empty, energy cooperation based on the lending and borrowing mechanism is realized in the energy cooperation set N1; if the energy cooperation set N1 is empty, the nodes in the cooperation set P1 compete to become the best forwarding node S according to the distance and energy value factors r , diffuse the energy demand signals of the sensor node S κ , and stop until there is no node in the network that can meet the energy demand conditions of the sensor node S κ , triggering an event interruption; S3: Energy cooperation based on lending and borrowing mechanism; in the energy cooperation set, the priority of the nodes in the energy cooperation set is determined according to whether the nodes participate in the energy cooperation and the energy value during the energy cooperation, and the energy cooperation nodes are selected; each selected energy cooperation node transmits power to the sensor nodes S κ according to a certain principle, so as to realize the energy cooperation among the nodes; in the S3, each selected energy cooperation node transmits power to the sensor nodes S κ according to a certain principle; (1) Energy repayment: the selected energy cooperation nodes in the lending and borrowing set finally repay the energy to the sensor node S κ The transferred energy is equal to the energy obtained from it before; at this time, any node in the lending and borrowing set is recorded as S br ; the energy consumed by it is: wherein is the node S br energy value acquired previously from the sensor node S κ ; is the energy conversion efficiency; m is the inter-node channel fading coefficient; T is the energy cooperation time; is the node S br channel value with the sensor node S κ ; is the actual distance between the node S br and the sensor node S κ ; (2) Energy borrowing:

1. Sensing node S κ borrowing the energy of the best forwarding node S r for the energy demand signal diffusion; the best forwarding node S r and the energy value consumed by its diffusion ED frame are recorded in the energy cooperation list and energy value table of the sensing node S κ ; 2. The nodes in the credit set or the non-credit set eventually forward to the sensor node S κ The total energy transferred is equal to the energy of the sensor node S κ At this time, the number of nodes in the credit set or the non-credit set affects the allocation of each node to the sensor node S;​ a. If there is only one node in the energy cooperation set, no matter the node belongs to the lending and borrowing set or the non-lending and borrowing set, the node is selected as the sensing node S κ The energy cooperation node of the sensing node S select is recorded as S; the energy consumed is: b. If there are multiple nodes in the energy cooperation set and these nodes belong to the lending and non-lending set respectively; allocate the nodes in each set to the sensor node S κ The transferred energy value; the nodes in each set allocate the sensor node S κ The problem is represented as follows, where any node in each set is denoted as S f :​ β f ∈(0,1] F＞1 where F is the number of nodes in the energy cooperation set; β f is a power allocation factor; is the node S f broadcasts the energy consumption value of the ED frame; The improved directional water injection algorithm is used to solve the problem, that is, less than half of the nodes are allocated The nodes with good channel conditions are allocated more than half of the nodes with poor channel conditions to the sink node D; the data transmission reliability of the remaining nodes is not affected κ The final acquisition ; the improved directional water injection algorithm is used to determine the power allocation factor of each node, and the nodes with power allocation factor not equal to 1 are selected as energy cooperation nodes; then the energy cooperation nodes transfer the corresponding energy values to the sensor nodes S κ ; after receiving the energy, the sensor nodes S κ complete data transmission, and each node updates its energy cooperation list and energy value table. 2.The energy cooperation method based on lending and returning mechanism under demand diffusion according to claim 1, characterized in that: In the S2, the formation of the energy cooperation set N1 is as follows: (1) a sensor node S κ when its own energy is less than the required energy, broadcasts an energy requirement signal to the surroundings, receives an ED frame from a node S κ The nodes that sent the ED frame form a cooperative set P1; the nodes in the cooperative set P1 calculate the maximum distance allowed for transferring the minimum energy required by S κ the maximum distance allowed for transferring the minimum energy required by S wherein node S p1 is any node in the cooperative set P1; is the energy conversion efficiency; m is the channel fading coefficient between nodes; T is the energy cooperation time; is the power when node S p1 transmits energy; is the energy consumption value of the current time slot sensing node S κ ; is the residual energy value of the last time slot sensing node S κ ; is the energy value collected by the current time slot sensing node S κ ; is the energy consumption value when the sensing node S κ broadcasts the ED frame; is the channel value between node S p1 and the sensing node S κ ; (2) S p1 With S κ actual distance and In comparison, if Less than Then node S p1 Add to the energy cooperation set N1, and to the cooperation set P1 and S p1 Nodes with similar conditions eventually form sensing node S. κ The energy cooperation set N1. 3.The energy cooperation method based on lending and returning mechanism under demand diffusion according to claim 2, characterized in that: The S2, the best forwarding node S r of the determination: when the energy cooperation set N1 is empty, the node in the cooperation set P1 starts the timer and sets the initial value of the respective timer; the node with the minimum final timer initial value competes to become the best forwarding node S r , and then S r diffuses the energy requirement signal of the sensor node S κ ; the initial value satisfies: wherein is the minimum energy requirement value for the sensor node S κ is the minimum energy requirement value for the sensor node S is the energy value for any node S p1 is the energy value for any node S κ is the energy value for any node S is the actual distance between the sensor node S p1 is the actual distance between the sensor node S κ is the actual distance between the sensor node S Optimal forwarding node S r After determination, the diffusion sensor node S κ 's energy requirement signal until there is no node in the network to meet the sensor node S κ 's energy requirement conditions, causing the event interruption.

4. The energy cooperation method based on lending and returning mechanism under demand diffusion according to claim 3, characterized in that: In the S3, energy cooperation based on the borrowing and returning mechanism: when any energy cooperation set is not empty, the priority of the nodes in the energy cooperation set is determined according to whether the nodes have participated in energy cooperation and the energy value at the time of energy cooperation, and the energy cooperation nodes are selected; for the convenience of description, the following will be referred to as the energy cooperation set; wherein the energy cooperation list is a set of the rest nodes which have implemented energy cooperation to the energy deficient node in the previous time slot; the energy value table is a set of energy values of the energy cooperation among the nodes in the previous time slot; for any node in the energy cooperation set, if the energy cooperation list of the node contains the sensor node S κ , a lending set is formed, otherwise a non-lending set is formed; the priority of the node in the energy cooperation set and the selected energy cooperation node are described as follows: (1) If the lending and borrowing set is empty, it means that the sensor node S κ Energy cooperation is not implemented to any node in the energy cooperation set; at this time, the priority of the nodes in the non-lending and borrowing set is the same, and part of the nodes are selected as energy cooperation nodes, which borrow energy from the sensor node S κ in the energy borrowing mode; the transmission power; after energy cooperation, the sensor node S κ implements data packet transmission; the nodes involved in the energy cooperation process update their own energy cooperation list and energy value table; (2) When the lending and borrowing set is not empty, it indicates that the sensor node S κ over- energy cooperation is realized to some nodes in the energy cooperation set; the nodes in the lending and borrowing set query their own energy value table to obtain the energy value of the previous cooperation with the sensor node S κ ; wherein any node S j in the lending and borrowing set is recorded as S j , j = 1, 2 …… J, J is the number of nodes in the lending and borrowing set; any node S κ previously cooperated with the sensor node S j is recorded as S ; the existing energy of any node S j is recorded as E , and the value is: wherein is the remaining energy of any node S j in the previous time slot; is the energy value collected by any node S j in the current time slot; a. If the energy value of each node in the lending and borrowing set satisfies and then the nodes in the lending and borrowing set with the same priority and both being the selected energy cooperation nodes transfer energy to the sensor node S κ according to the energy return mode. b. If the energy values of the nodes in the lending and borrowing set satisfy But Wherein The nodes with high priority are all selected energy cooperation nodes, and transfer energy to the sensor node S κ in the energy returning mode; the rest of the nodes in the lending and borrowing set have low priority, part of which are selected as energy cooperation nodes, and transfer energy to the sensor node S κ in the energy borrowing mode; c. If the energy values of the nodes in the lending set satisfy and the non-lending set is not empty; the nodes in the lending set have high priority and are all selected as energy cooperation nodes, transfer energy to the sensor node S κ according to the energy return mode; the nodes in the non-lending set have low priority, part of which are selected as energy cooperation nodes, transfer energy to the sensor node S κ according to the energy borrowing mode; d.If the energy value of each node in the lending and borrowing set meets But the non-lending and borrowing set is not empty; the node priority in the lending and borrowing set is the same, wherein part of the nodes are selected as energy cooperation nodes, and the energy is borrowed from the sensor node S κ Energy transfer; After the energy cooperation, the sensor node S κ Data transmission is realized; The nodes involved in the energy cooperation process update their respective energy cooperation lists and energy value tables.

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