Collaborative node forwarding selection method for complex environment

Abstract

The invention discloses a cooperative node forwarding selection method oriented to a complex environment. Each node comprises a sensing module, a calculation module, a decision sending module, a decision receiving module, a sending module and a receiving module. The sensing module needs to ensure sensing of the sending node; state information of neighbor nodes and destination nodes; the sensing module uses active acquisition and passive acquisition sensing; the information which must be perceived comprises the moving speed, the position and the power consumption of a one-hop neighbor node and the hop count from a destination node; the calculation module needs to ensure that the sending node calculates the cooperative selection weight of the neighbor node according to the information sensed by the sensing module; the sending decision module needs to enable a sending node to decide possible cooperative nodes according to the calculation module; when the receiving node receives the signal, the receiving decision module judges whether the node should participate in forwarding; the sending module and the receiving module are responsible for coding, sending, receiving and decoding of signals; the calculation module needs to calculate the cooperative selection weight of the neighbor nodes.

Description

Technical Field

[0001] The invention relates to the technical field of software radio, in particular to a coordinated node forwarding selection method facing complex environments in a mobile ad hoc network. Background Art

[0002] Mobile ad hoc networks are self-organizing networks that do not require fixed infrastructure and are connected wirelessly. Their core features are that nodes can automatically form networks and dynamically adapt to topology changes. In actual scenarios, ad hoc networks may face complex environments, where nodes have high mobility and the network topology is constantly changing, resulting in easy link interruption and unstable transmission paths. In addition, complex environments also include various wireless interference, bandwidth limitations, high traffic demand and other issues, which can also affect communication quality. How to ensure stable end-to-end transmission of information as much as possible and reduce packet loss is an important challenge. Traditional ad hoc networks have the following problems: 1) The transmission topology of a single path changes rapidly and the transmission reliability is poor. Since there is only one link from the source node to the destination node, when the network topology changes or there is interference, the link is easily interrupted and the transmission reliability cannot be guaranteed; 2) The demodulation performance is poor under fading channels. In complex environments, the impact of wireless channel fading may be very obvious. Traditional single-path transmission faces problems such as large link loss, poor received signal quality, and severe packet loss rate.

[0003] To address the limitations of traditional methods, we can refer to Barrage Relay Networks (BRN). The core idea of ​​BRN is that a single wireless link may be poorly connected due to fading, but multiple fading channels are independent, so the possibility of all signal components fading at the same time is greatly reduced, and network connectivity is improved by exploiting cooperative diversity. Using these techniques, BRN performs cooperative and collaborative processing on received signals to achieve autonomous cooperative communication. The medium access control protocol of BRN adopts TDMA, and time is cut into many time slots. When a relay node receives a data packet from an upstream neighbor node, it forwards the data packet in the next time slot. BRN uses multiple cooperative nodes to communicate concurrently to form a virtual antenna array, thereby enhancing link redundancy and improving the diversity gain of the receiving node.

[0004] However, using cooperative node forwarding still faces some problems, such as: 1) In complex environments, the fast movement of nodes may cause link instability. 2) Nodes frequently forward data packets, resulting in high energy consumption. This is especially evident in battery-powered mobile nodes. 3) Selecting multiple cooperative forwarding nodes will occupy more bandwidth resources, especially in areas with dense nodes, which will cause broadcast storms or network congestion, resulting in reduced system performance. How to select cooperative nodes to ensure the stability of the selected link, control data packet redundancy, and extend network life is the key to improving network performance.

[0005] CN2022107048754 discloses a mobile ad hoc network communication method, device, system and storage medium. The method includes: receiving a networking signaling sent by an adjacent node of the receiving node; the networking signaling includes a stable routing flag and hop count information, the stable routing flag represents the first path transmission state of the adjacent node to a specified node in the ad hoc network, and the hop count information represents the number of forwarding times of the adjacent node to a specified node in the ad hoc network; based on the received networking signaling, the second path transmission state from the receiving node to the specified node is obtained; according to the first path transmission state or the second path transmission state, the routing table of the receiving node is updated. When networking, each node broadcasts its own stable routing flag to each other and builds / updates the routing table. The most stable next hop node for reaching the specified node can be obtained in the routing table of each node, thereby improving the connectivity rate between two distant nodes. The technical solution task of the present invention is not involved. Summary of the invention

[0006] The purpose of the present invention is to adopt cooperative communication technology to address the problems that may be included in wireless ad hoc networks, such as unstable link states, high node energy consumption caused by multi-node collaboration, and more bandwidth resources occupied. By selecting multiple cooperative nodes to forward in the same time slot, a virtual antenna array is formed, and multiple signal samples that have experienced independent fading are merged at the receiving end to obtain higher diversity gain and communication link redundancy, thereby combating fading and interference in the wireless channel and improving receiving performance. On the basis of perceiving some neighbor node information, some suitable nodes are selected as cooperative nodes based on factors such as node willingness, mobile speed, link quality, etc., so as to improve the communication quality as much as possible while reducing the additional overhead brought to the network.

[0007] The technical solution of the present invention is a collaborative node forwarding selection method for complex environments. In the collaborative node selection technical solution used, the node composition includes a perception module, a calculation module, a sending decision module, a receiving decision module, a sending module and a receiving module; each module and its function are as follows: Figure 1 As shown, where:

[0008] The perception module needs to ensure that the sending node perceives the status information of neighboring nodes and destination nodes.

[0009] The calculation module needs to ensure that the sending node calculates the collaborative selection weights of neighbor nodes based on the information perceived by the perception module.

[0010] The sending decision module needs to enable the sending node to determine the possible cooperative nodes based on the calculation module.

[0011] When a receiving node receives a signal, the receiving decision module determines whether the node should participate in forwarding.

[0012] The sending module and the receiving module are responsible for the encoding and sending and receiving and decoding of the signal.

[0013] The above-mentioned perception module can use active acquisition and passive acquisition perception. The information that must be perceived is the moving speed, location, power consumption and number of hops from the destination node of the one-hop neighbor node.

[0014] The above calculation module needs to calculate the cooperative selection weight of the neighboring node. For the sending node ni to calculate the cooperative selection weight w of a neighboring node nj, the specific process is as follows:

[0015] Step 1: Through neighbor node n j The moving speed and location information of the link duration are used to calculate the influence factor w of the collaborative selection. t .

[0016] Step 2: Calculate the influence factor w of node willingness on collaborative selection o .

[0017] Step 3: Calculate the influence factor w of the transmission loss from source to collaboration and the forwarding distance from collaboration to destination node on collaboration selection p .

[0018] Step 4: Based on the above indicators, calculate the collaborative selection weight w=a of the neighbor node nj t ·w t +a o ·w o +a p ·w p , where a t ,a o ,a p The weight can be customized or dynamically adjusted according to the scenario requirements, or determined by the sending decision module.

[0019] For the above step 1, w t The flow chart of the calculation method is as follows Figure 2 The specific instructions are as follows:

[0020] 1) Get the coordinates of this node (x i ,y i ,z i ) and the coordinates of the neighboring nodes (x j ,y j ,z j ). According to the coordinate information, we can get node n i and n j Distance

[0021]

[0022] 2) According to n jThe speed information and node n i The speed of the node itself can be obtained by i Relative to n j The speed of j Relative to n i The relative speed is expressed as follows:

[0023]

[0024] 3) After calculating the relative speed and distance of the nodes, project the node motion map in three-dimensional space onto the plane where the relative speed and the two nodes are located. The distance perpendicular to the movement path of adjacent nodes is calculated as follows:

[0025]

[0026] 4) The time interval during which the link remains active is called the link duration. It can be concluded that the link duration between nodes ni and nj is

[0027]

[0028] Where R is the maximum communication distance. For the positive and negative signs in the formula, and Take positive when in the same direction and negative when in opposite directions.

[0029] 5) According to t ld The historical reception information can be ld Normalized to a number between 0 and 1 w t , to measure the contribution of link duration to the selection of collaborative nodes.

[0030] For the above step 2, w o The specific calculation method is as follows. First, calculate n j The energy consumption rate P can be used to infer the rate at which the remaining energy decreases. Where t represents time, such as 100s. ΔE represents the energy consumed during time t. The node life can be expressed as To predict, where E is the remaining energy of the node. Similar to step 5) in step 1, normalize T and record its value as w o .

[0031] For the above step 3, w p The calculation method of transmission path loss P is as follows. L It can be calculated by the distance d between two nodes. The calculation formula is as follows:

[0032]

[0033] Among them G lIt is the square of the product of the gains of the transmitting antenna and the receiving antenna, and λ is the wavelength of the signal.

[0034] Node n i To destination node n j The effective forwarding distance is use Measure the influence of node position and normalize to get w p .

[0035] In the above sending decision module, the sending node n i Sort all neighbor nodes according to the w value, and select the largest n nodes as possible collaborative nodes. There may be multiple sending nodes at the same time, and they all need to select possible collaborative nodes. All sending nodes send at the same time. The specific value of n can be determined in advance or adjusted according to the environment.

[0036] In the above sending module, when the source node generates a data packet, the data packet needs to contain the remaining transmission hop count information and packet ID information. The former indicates how many times the packet can be forwarded, and the latter indicates a unique packet. These can be obtained through the perception module. For forwarding data packets, the packet needs to be re-encoded and the remaining transmission hop count of the packet is reduced by one. In order to ensure that multiple sending nodes send at the same time, form a virtual antenna array, and play the role of increasing redundant links and improving receiving gain, the system needs to operate in time division multiple access mode.

[0037] In the above receiving module, the receiving node needs to decode packets sent by multiple nodes at the same time, which can be regarded as a multiple-input single-output (MISO) problem. The node can combine multipath signals through MIMO technology, equalization technology, etc. to improve the receiving gain. If the decoding fails, it will not become a forwarding node, otherwise the decoding information will be handed over to the receiving decision module.

[0038] In the above receiving decision module, if the receiving node is not selected as the cooperative forwarding node, it is directly abandoned and does not become a cooperative receiving node. Otherwise, the receiving node obtains the decoded packet content. If the remaining transmission hop count of the packet is less than the hop count from the node to the destination node, or the ID of the packet has been received, it will not be forwarded. Otherwise, it becomes a sending node and forwards in the next time slot.

[0039] The effect of using this collaborative selection algorithm is as follows Figure 3 As shown in Figure 1, in each time slot, the sending node will select some nodes as cooperative nodes according to the above cooperative selection algorithm, and these nodes will send in the next time slot after successful reception. And the sending nodes send together to enhance link redundancy and gain at the receiving end.

[0040] Beneficial effects: The present invention allows nodes to select multiple collaborative nodes when sending information, and enables these nodes to forward simultaneously to form a virtual antenna array. The advantages of this method are as follows: 1) This method uses multipath transmission. When interference or topology changes cause one path to be interrupted, there are multiple other paths that can complete information transmission. Therefore, compared with traditional self-organizing waveforms, this method enhances transmission reliability. 2) This method can overcome channel fading and improve demodulation performance. Collaborative communication enables each collaborative node to share an antenna. These nodes send consent signals at the same time. The receiver can increase the channel capacity through diversity reception and overcome channel fading to a certain extent.

[0041] The collaborative selection algorithm used in the present invention integrates multiple parameters, including node speed, node willingness, node location, etc., which respectively represent link duration, node power consumption, path loss, packet transmission distance, etc., which can be used as a basis for measuring forwarding effect. And when the system selects collaborative nodes, it can adjust the weight of each indicator according to the environment, so as to maintain high flexibility when dealing with complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the functional modules of the collaborative node and their functions;

[0043] Figure 2 is the effect of link duration in the cooperative selection algorithm w t Calculation flow chart;

[0044] Figure 3 This is a schematic diagram of the effect of using the collaborative selection algorithm in the network topology;

[0045] Figure 4 is a schematic diagram of a topological scenario of an embodiment; DETAILED DESCRIPTION

[0046] The invention will be further described below through simulation examples.

[0047] This embodiment uses Python to simulate and set a scene with a uniform channel environment. There are 20 nodes in the scene, and the average connectivity of the nodes is 3. The scene topology diagram after initialization is as follows: Figure 4 shown.

[0048] In the simulation system, the time is set to equally spaced time slots, and all events will not be executed across time slots. This ensures that the system runs in TDMA mode. The movement of nodes in the network obeys the random walk model, that is, the node selects a time period, and the node independently and randomly selects the movement speed and direction in each time period t. The direction θ(t) selected by the node satisfies the uniform distribution on [0,2π]; the speed v(t) obeys [v min ,v max] is uniformly distributed on the edge. When a node moves to the boundary, it changes direction and continues to move according to the law of light reflection. After a step, the node randomly selects a new direction and speed to move (another step), and the above process is repeated until the simulation ends.

[0049] The node end-to-end transmission process in the simulation is implemented as follows:

[0050] Step 1: Before transmitting information, each node needs to have information about the surrounding one-hop neighbor nodes and the destination node. The information about the one-hop neighbor nodes includes power consumption, movement speed, coordinates, etc. The information about the destination node includes the coordinates of the destination node and the number of hops from the node to the destination node. This information will be used for collaborative node selection. In Python implementation, this information will be encapsulated into a structure and then transmitted between nodes. Nodes can obtain this information through the information acquisition module. The working principle of the information acquisition module will be introduced below. One hop means passing through a node in the network. If the packet exceeds this node, it will be discarded to prevent network congestion 8-bit protocol.

[0051] Step 2: When the source node encapsulates the data packet, it needs to add TTL and PID (packet ID) fields in the packet header. The TTL value is the number of hops from the source node to the destination node, and the PID is a unique value generated by the source node to distinguish different packets. In the next time slot, the source node will become the sending node. In the Python implementation, two additional member variables, TTL and PID, need to be added to the data packet structure. And each node needs a member to store the node status. At the beginning of each time slot, all nodes in the sending state start sending.

[0052] Step 3: Each sending node will select some nodes as cooperative nodes according to the cooperative selection algorithm. All selected cooperative nodes will become sending nodes in the next time slot. Note that different sending nodes may choose the same node as a cooperative node. Since these sending nodes will send at the same time, the received signal of the node is enhanced. In the simulation implementation, the transmission power can be set in advance, the signal strength at the receiving end can be determined by the Rice channel model, and the enhancement of the received signal can be simulated by the maximum ratio combining algorithm.

[0053] Step 4: After the selected cooperative node receives the signal, it needs to decode the received signal. It can calculate the interruption probability through the signal-to-noise ratio to determine whether the packet is successfully received. For the successfully received packet, the PID and TTL of the packet are recorded. If the PID has been received before, or the TTL field is less than the number of hops from the cooperative node to the destination node, it does not need to be forwarded. Otherwise, the packet needs to be re-encoded, the TTL field in the packet is reduced by 1, and the node state is changed to sending, so that it becomes a sending node in the next time slot.

[0054] Step 5: Repeat steps 3 and 4 until the TTL field in the data packet is reduced to 0. If the destination node decodes the packet successfully, it means that the end-to-end transmission is successful, otherwise it fails.

[0055] The specific implementation of each module is as follows:

[0056] For the sending module, when sending a packet, a data structure is generated according to the business or forwarding requirements and stored in the global queue. In the next time slot, for each packet in the queue, all receiving modules of the nodes within the receiving range receive it.

[0057] For the receiving module, when receiving a packet, it is necessary to simulate the multipath reception method so that all possible cooperative nodes can complete the reception of information sent by multiple sending nodes. In the simulation, the signal-to-noise ratio of a single link is obtained through the Rice channel model. For multipath reception, the combined signal-to-noise ratio is calculated through maximum ratio combining, and then the interruption probability is calculated to determine whether the decoding can be successful.

[0058] The node's perception module is implemented in two ways: passive acquisition and active acquisition, which jointly acquire perception information. The specific implementation methods are as follows:

[0059] In the passive acquisition mode, the node will try to seize the time slot when it is idle. If the seizure is successful, the node's state is set to the sending state, and the node sends the state of itself and its one-hop neighbors in the next time slot, including the location of these nodes, remaining energy, etc. The node that receives this information can update the local record accordingly. This information will be used in the collaborative selection algorithm. This information should not be forwarded.

[0060] In the active acquisition mode, the source node will send routing addressing information. The addressing information needs to have the source node ID and the destination node ID, and the TTL is set to 255. The routing addressing information is transmitted through time division multiple access. The difference is that all nodes that receive the information need to decode it and forward it in the next time slot. After receiving the routing addressing message, the destination node will send a routing response, including the source node ID, the destination node ID and the destination node location, and set the TTL to 255. After receiving the routing response, the remaining nodes will also decode and forward it. In the end, all nodes in the network will obtain the location information of the destination node, as well as the number of hops from the source node and the destination node. In the simulation implementation, you only need to add the corresponding fields to the data structure and fill them in correctly. If the node information has been updated recently, you do not need to actively acquire it to reduce system overhead.

[0061] The calculation module is implemented as follows:

[0062] Step 1: First calculate the neighbor node n j The influence of the moving speed on the collaborative selection is calculated as follows:

[0063] 1) Get the coordinates of this node (x i ,y i ,z i ) and the coordinates of the neighboring nodes (x j ,y j ,z j ). These can be obtained from the data packet structure of the passive transmission process. According to the coordinate information, node n can be obtained i and n j Distance:

[0064]

[0065] 2) According to n j The speed information and node n i The speed of the node itself can be obtained i Relative to n j This information can also be obtained from the packet structure of the passive transmission process. j The relative speed with respect to ni is expressed as follows:

[0066]

[0067] 3) After calculating the relative speed and distance of the nodes, project the node motion map in three-dimensional space onto the plane where the relative speed and the two nodes are located. The distance perpendicular to the movement path of adjacent nodes is calculated as follows:

[0068]

[0069] 4) The time interval during which the link remains active is called the link duration. It can be concluded that the link duration between nodes ni and nj is

[0070]

[0071] Where R is the maximum communication distance, which is set to 1000m in the implementation. and Take positive when in the same direction and negative when in opposite directions.

[0072] 5) You can use t ld Normalized to a number between 0 and 1 t , to measure the contribution of link duration to the selection of cooperative nodes. Each time t is calculated for a node ld , you need to record the value and update the total number of calculations total. When total is equal to a given value, each time the latest t ld When t ld The larger value is a. Then the normalized value When the system initializes total=0, w t =0.5. In the implementation, a fixed-length sliding window is used to save valid values. If the window is not full, it is filled. If it is full, the window is moved, the oldest data is removed and then filled. The sliding window length is set to 256, which reduces the impact of outdated data while ensuring the amount of data.

[0073] Step 2: Calculate the impact of node willingness on collaborative selection, including node energy consumption. In simulation, node energy consumption can be modeled as a function of usage time t use And the number of packets sent num send Positive correlation, that is, E remain =E init -a×t use -b×num send . Where E init Set to 100, a to 0.01, and b to 0.05. First calculate n j The energy consumption rate P can be used to infer the rate at which the remaining energy decreases. Where t represents time, which is 20s in this example. ΔE represents the energy consumed in time t. The node life can be expressed as To predict, where E is the remaining energy of the node. By using a similar method as step 5) in step 2, T is normalized and its value is recorded as w o .

[0074] Step 3: Calculate the impact of node location on collaborative selection, including the transmission loss from source to collaborative and the forwarding distance from collaborative to destination node.

[0075] Transmission path loss P L It can be calculated by the distance d between two nodes. The calculation formula is as follows:

[0076]

[0077] Among them G l It is the square of the product of the gains of the transmitting antenna and the receiving antenna, which is set to 40 here, and λ is the wavelength of the signal, which is set to 0.2m.

[0078] Node n i To destination node n j The forwarding distance is use Measure the influence of node position and normalize to get w p .

[0079] Step 4: According to the above indicators, calculate the neighbor node n j The synergistic effect of w = a t ·w t +a o·w o +a p ·w p In the embodiment, a t ,a o ,a p Initially, they are all set to 1, which means that the influence of the three factors is evenly considered. remain When it drops below 30%, it is considered that the power consumption of the entire system is large. o Adjusting to 3 increases the weight of power consumption to extend the life of the entire system.

[0080] For the sending decision module, the sending node n i Sort all neighbor nodes according to the w value, and select the largest n nodes as possible cooperative nodes. There may be multiple sending nodes at the same time, and they all need to select possible cooperative nodes. The system's time division multiple access mechanism ensures that all sending nodes send at the same time. The specific value of n in the simulation is 3.

[0081] For the receiving decision module, the node first needs to determine whether it is the selected collaborative node, which will be notified by the sending node in the perception before each end-to-end connection is established. The receiving decision module analyzes the packet content. If the remaining transmission hop count is not less than the hop count from the node to the destination node, and the packet ID has never been received, the packet needs to be forwarded, and the node becomes a collaborative node and a sending node in the next time slot. Otherwise, no action is taken.

[0082] This algorithm can be compared with the traditional routing algorithm using the Digi-Tesla algorithm. Define the number of packets sent by the source node in the system as n s , the number of times the destination node successfully receives the packet is n r The transmission success rate is defined as In the simulation results, when using the traditional routing method, p is 0.91, while when using the cooperative node forwarding, p is 0.96. It can be seen that when using this method, the transmission success rate is significantly improved.

[0083] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes are also included within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose.

Claims

1. A collaborative node forwarding selection method for complex environments, characterized in that: Each node consists of a perception module, a calculation module, a sending decision module, a receiving decision module, a sending module and a receiving module; The perception module needs to ensure that the sending node perceives the status information of the neighboring nodes and the destination node. The above perception module uses active acquisition and passive acquisition perception. The information that must be perceived includes the moving speed, location, power consumption and number of hops from the destination node of the one-hop neighbor node. The calculation module needs to ensure that the sending node calculates the cooperative selection weight of the neighbor node based on the information perceived by the perception module; The sending decision module needs to enable the sending node to determine the possible cooperative nodes based on the calculation module; When the receiving node receives a signal, the receiving decision module determines whether the node should participate in forwarding; The sending module and receiving module are responsible for the encoding and sending and receiving and decoding of signals; The above calculation module needs to calculate the cooperative selection weight of neighbor nodes: for the sending node ni, calculate a neighbor node n j The specific process of collaborative selection weight w is as follows: Step 1: Through neighbor node n j The moving speed and location information of the link duration are used to calculate the influence factor w of the collaborative selection. t ; Step 2: Calculate the influence factor w of neighbor node willingness on collaborative selection o ; Step 3: Calculate the influence factor w of the transmission loss from the source node (sending node) to the collaboration and the forwarding distance from the collaboration to the destination node on the collaboration selection p ; Step 4: Based on the above indicators, calculate the collaborative selection weight w=a of the neighbor node nj t ·w t +a o ·w o +a p ·w p , where a t ,a o ,a p The weights can be customized or dynamically adjusted according to the scenario requirements, or determined by the sending decision module; For the above step 1, w t The calculation process is as follows: 1) Get the coordinates of this node (x i ,y i ,z i ) and the coordinates of the neighboring nodes (x j ,y j ,z j ); According to the coordinate information, node n can be obtained i and n j Distance 2) According to n j The speed information and the node n i The speed of the node itself can be obtained by i Relative to n j Speed; n j Relative to n i The relative speed is expressed as follows: 3) After calculating the relative speed and distance of the nodes, project the node motion map in the three-dimensional space onto the plane where the relative speed and the two nodes are located; the distance perpendicular to the movement path of the adjacent nodes is calculated as follows: 4) The time interval during which a link remains active is called link duration; It can be concluded that the link duration between nodes ni and nj is Where R is the maximum communication distance; for the positive and negative signs in the formula, and Take positive when in the same direction, and negative when in opposite directions; 5) According to t ld The historical reception information can be ld Normalized to a number between 0 and 1 w t , to measure the contribution of link duration to the selection of collaborative nodes; Step 2 o The calculation method is as follows: first calculate the energy consumption rate P of nj, and then infer its remaining energy decrease rate; Where t represents time, such as 100s; ΔE represents the energy consumed during time t; the node life can be expressed as To predict, where E is the remaining energy of the node; T is normalized to a number between 0 and 1, and its value is recorded as w o ; Step 3 p The calculation method of transmission path loss P is as follows; L It can be calculated by the distance d between two nodes. The calculation formula is as follows: Among them G l is the square of the product of the gains of the transmitting antenna and the receiving antenna, and λ is the wavelength of the signal; Node n i To destination node n j The effective forwarding distance is use Measure the influence of node position and normalize to get w p ; In the above sending decision module, the sending node n i All neighbor nodes are sorted according to the w value, and the largest n nodes are selected as possible collaborative nodes; there may be multiple sending nodes at the same time, and they all need to select possible collaborative nodes; all sending nodes send at the same time; the specific value of n can be determined in advance and can also be adjusted according to the environment.

2. The method for selecting a coordinated node forwarding in a complex environment according to claim 1, characterized in that: In the above sending module, when the source node generates a data packet, the data packet needs to contain the remaining transmission hop count information and packet ID information. The former indicates how many times the packet can be forwarded, and the latter indicates a unique packet. These can be obtained through the perception module. When forwarding a data packet, the packet needs to be re-encoded and the remaining transmission hop count of the packet is reduced by one. In order to ensure that multiple sending nodes send at the same time, form a virtual antenna array and play the role of increasing redundant links and improving receiving gain, the system operates in time division multiple access mode. In the above receiving module, the receiving node needs to decode packets sent by multiple nodes at the same time, which is regarded as a multiple-input single-output (MISO) problem. The node can combine multipath signals through MIMO technology, equalization technology, etc. to improve the receiving gain; if the decoding fails, it will not become a forwarding node, otherwise the decoding information will be handed over to the receiving decision module; In the above receiving decision module, if the receiving node is not selected as the cooperative forwarding node this time, it is directly abandoned and does not become a cooperative receiving node; Otherwise, the receiving node obtains the decoded packet content; if the remaining transmission hop count of the packet is less than the hop count from the node to the destination node, or the ID of the packet has been received before, it will not be forwarded; Otherwise, it becomes a sending node and forwards in the next time slot.

3. The method for selecting a coordinated node forwarding in a complex environment according to claim 1, characterized in that: In each time slot, the sending node will select some nodes as cooperative nodes according to the above cooperative selection algorithm. These nodes will send in the next time slot after successful reception; and the sending nodes send together to enhance link redundancy and gain at the receiving end.

4. The method for selecting a coordinated node forwarding in a complex environment according to claim 1, characterized in that: Select multiple cooperative nodes and make them forward simultaneously to form a virtual antenna array.

5. The method for selecting a coordinated node forwarding in a complex environment according to claim 1, characterized in that: The time is set to equally spaced time slots, and all events will not be executed across time slots; thus ensuring that the system runs in TDMA mode; the movement of nodes in the network obeys the random walk model, that is, the node selects a time period, and the node independently and randomly selects the movement speed and direction within each time period t; the direction θ(t) selected by the node satisfies the uniform distribution on [0,2π]; the speed v(t) obeys [v min ,v max ]; when a node moves to the boundary, it changes direction and continues to move according to the law of light reflection; after a step, the node randomly selects a new moving direction and speed to move, which is another step, and the above process is repeated until the end of the simulation; The node end-to-end transmission process in the simulation is implemented as follows: Step 1: Before transmitting information, each node needs to have information about the surrounding one-hop neighbor nodes and the destination node. The one-hop neighbor node information includes power consumption, movement speed, coordinates, etc. The destination node information includes the destination node coordinates and the number of hops from the node to the destination node. This information will be used for collaborative node selection. In Python implementation, this information will be encapsulated into a structure and passed between nodes. Nodes can obtain this information through the information acquisition module. The working principle of the information acquisition module will be introduced below. Step 2: When the source node encapsulates a data packet, it needs to add TTL and PID (packet ID) fields in the packet header. The TTL value is the number of hops from the source node to the destination node, and the PID is a unique value generated by the source node to distinguish different packets. In the next time slot, the source node will become the sending node. In Python implementation, it is necessary to add two additional member variables, TTL and PID, to the data packet structure. Each node needs a member to store the node status. At the beginning of each time slot, all nodes in the sending state start sending. Step 3: Each sending node will select some nodes as cooperative nodes according to the cooperative selection algorithm; all selected cooperative nodes will become sending nodes in the next time slot; note that different sending nodes may select the same node as a cooperative node, because these sending nodes will send at the same time, which enhances the received signal of the node; in the simulation implementation, the sending power can be set in advance, the signal strength at the receiving end can be determined by the Rice channel model, and the enhancement of the received signal can be simulated by the maximum ratio combining algorithm; Step 4: After receiving the signal, the selected collaborative node needs to decode the received signal. The interruption probability can be calculated by the signal-to-noise ratio to determine whether the packet is successfully received. For successfully received packets, the PID and TTL of the packet are recorded. If the PID has been received before, or the TTL field is less than the number of hops from the coordinating node to the destination node, there is no need to forward it; Otherwise, the packet needs to be re-encoded, the TTL field in the packet is reduced by 1, and the node state is changed to sending, so that it becomes a sending node in the next time slot; Step 5: Repeat steps 3 and 4 until the TTL field in the data packet is reduced to 0; if the destination node decodes the packet successfully, it means that the end-to-end transmission is successful, otherwise it fails.

6. The method for selecting cooperative node forwarding in complex environments according to claim 1, characterized in that: The specific implementation of each module is as follows: For the sending module, when sending a packet, a data structure is generated according to the business or forwarding requirements and stored in the global queue; in the next time slot, for each packet in the queue, the receiving modules of all nodes within the receiving range receive it; For the receiving module, when receiving a packet, it is necessary to simulate the multipath reception method so that all possible cooperative nodes can complete the reception of information sent by multiple sending nodes. In the simulation, the signal-to-noise ratio of a single link is obtained through the Rice channel model. For multipath reception, the combined signal-to-noise ratio is calculated through maximum ratio combining, and then the interruption probability is calculated to determine whether the decoding can be successful. The node's perception module is implemented in two ways: passive acquisition and active acquisition, which jointly acquire perception information. The specific implementation methods are as follows: In the passive acquisition mode, a node will try to seize a time slot when it is idle. If the seizure is successful, the node's state will be set to the sending state, and the node will send its own and one-hop neighbor's states in the next time slot, including the location of these nodes, remaining energy, etc. The node that receives this information can update its local record accordingly. This information will be used in the collaborative selection algorithm. This information should not be forwarded. In the active acquisition mode, the source node will send routing addressing information. The addressing information needs to have the source node ID and the destination node ID, and the TTL is set to 255; the routing addressing information is transmitted through time division multiple access. The difference is that all nodes that receive the information need to decode it and forward it in the next time slot; after receiving the routing addressing message, the destination node will send a routing response, including the source node ID, the destination node ID and the destination node location, and set the TTL to 255; after receiving the routing response, the remaining nodes will also decode and forward it; eventually all nodes in the network will obtain the location information of the destination node, as well as the number of hops from the source node and the destination node; in the simulation implementation, you only need to add the corresponding fields to the data structure and fill them in correctly; if the node information has been updated recently, you do not need to actively acquire it to reduce system overhead; For the sending decision module, the sending node ni sorts all neighbor nodes according to the w value and selects the largest n nodes as possible cooperative nodes; there may be multiple sending nodes at the same time, and they all have to select possible cooperative nodes; the system's time division multiple access mechanism ensures that all sending nodes send at the same time; the specific value of n in the simulation is 3; For the receiving decision module, the node first needs to determine whether it is the selected collaborative node, which will be notified by the sending node in the perception before establishing each end-to-end connection; The receiving decision module analyzes the packet content. If the remaining transmission hop count is not less than the hop count from the node to the destination node, and the packet ID has never been received, the packet needs to be forwarded, the node becomes a collaborative node, and becomes a sending node in the next time slot, otherwise no action is taken.

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