Multi-frequency three-dimensional networking system and elastic network control method

Abstract

The invention discloses a multi-frequency three-dimensional networking system and an elastic network control method, and the method is implemented based on the system, and comprises the following steps: based on multi-frequency three-dimensional networking, realizing multi-subnet parallel transmission through frequency division multiple access and time division multiple access; dynamically electing cluster head nodes and dividing task subnets by adopting a hierarchical clustering networking method; through elastic transmission control, interference detection and available frequency decision are carried out by adopting a cooperative interference detection method, and dynamic spectrum access is supported; elastic networking control is carried out through a multi-hop simulcasting mechanism, network signaling is broadcasted, and whole network coverage is completed in combination with a decoding forwarding strategy and a physical layer diversity receiving technology; the cluster head node executes dynamic network management and performs task subnet management, member management, dynamic time slot allocation and spectrum resource optimization, so that efficient and reliable online network control is realized, and the networking flexibility and the communication confrontation capability are improved; high-reliability, low-overhead and other multi-frequency three-dimensional networking and elastic network control thereof are realized.

Description

Technical Field

[0001] The present invention relates to the field of data link communication technology, and in particular to a multi-frequency three-dimensional networking system and an elastic network control method. Background Art

[0002] Manned-unmanned formation coordinated operations (MUM-T) is one of the main combat styles of future multi-domain coordinated operations. It refers to manned platforms deploying unmanned platforms through vehicles, and implementing command and control and resource sharing of unmanned platforms and their mission payloads through data link communication means, making full use of the low-cost and consumable advantages of unmanned platforms, expanding the combat space of manned platforms, and improving the situational awareness, penetration and killing, and survivability of manned platforms.

[0003] With the support of an unmanned formation collaborative combat system, the use of highly intelligent unmanned platforms to conduct integrated discovery, identification and saturation strikes on high-value targets can have a huge deterrent effect on the enemy and have a high combat cost-effectiveness. The asymmetric advantage in war costs can have a huge impact on the overall combat situation.

[0004] Existing unmanned data link communication systems include V / UHF tracking and control data links, L-band formation coordination links, and UHF / L-band unmanned broadband radios. These primarily utilize planar ad hoc networks for collaborative networking communications. These networks typically employ a mesh topology to expand network connectivity, a contention-based access protocol for point-to-multipoint transmission, and a multi-hop routing protocol for beyond-line-of-sight transmission and extended network coverage.

[0005] Typically, some or all nodes in a mesh network topology have neighbor relationships and can be connected through line-of-sight communication. Other nodes achieve multi-hop connections and end-to-end data transmission with non-adjacent nodes through ad hoc network routing tables.

[0006] Typically, contention access protocols for planar ad hoc networks include Aloha random access, carrier sense multiple access (CSMA), and statistical priority multiple access (SPMA). Aloha random access allows nodes to directly access wireless shared channels, but this can lead to packet collisions and cannot guarantee successful data transmission. The CSMA protocol supports wireless channel sensing and collision avoidance mechanisms, reducing the probability of packet collisions and supporting QoS priorities. The SPMA protocol supports asynchronous frequency hopping networking, features network traffic awareness and collision resolution mechanisms, and supports multiplexing of wireless shared channels, improving channel utilization.

[0007] Typical routing protocols for flat ad hoc networks include Destination Sequence Distance Vector (DSDV), Optimized Link State LR (OSLR), Ad Hoc On-Demand Vector Routing (AODV), and Dynamic Source Routing (DSR). DSDV and OLSR are table-driven routing strategies that update routing tables through periodic broadcast signaling. They feature low packet transmission latency and high protocol overhead. AODV and DSR are demand-driven routing strategies that trigger routing table establishment and maintenance through data packets. They exhibit high packet transmission latency and the potential for routing errors.

[0008] The unmanned collaborative ad hoc communication system based on planar ad hoc networks has the characteristics of low transmission rate, small networking capacity, long network convergence time, weak anti-interference ability, and does not support dynamic network reconstruction functions oriented to tasks or tactical intentions.

[0009] In the tactical frontier communication environment facing strong enemies, the unmanned data link communication system that relies on static network planning and initial configuration can only support limited communication scenarios, lacks flexibility and confrontation capabilities, and has weaknesses such as weak environmental adaptability and lack of anti-damage capabilities.

[0010] Traditional planar ad hoc communication systems use fixed-frequency / narrowband frequency-hopping communications for point-to-multipoint transmission and multi-hop routing technology for beyond-line-of-sight communication, extending network coverage and communication distance. However, fixed-frequency / narrowband frequency-hopping communications rely on initial frequency planning, resulting in limitations in network scale, flexibility, channel adaptability, and communication countermeasures.

[0011] (1) Limited network scale: The communication capacity of fixed-frequency communication / narrowband frequency hopping is limited, and the available network bandwidth decreases inversely with the increase in the number of network nodes, which limits the network scale of planar ad hoc networks;

[0012] (2) Insufficient networking flexibility: The time and frequency resource allocation of planar ad hoc networks mainly relies on initial network planning. The resource reservation access mechanism based on distributed coordination occupies network bandwidth, resulting in large network overhead and insufficient networking flexibility.

[0013] (3) Insufficient channel adaptability: Planar ad hoc networks use neighbor discovery protocols to sense link quality. To reduce network overhead, link quality sensing carries little information and cannot reflect the impact of time-varying channel characteristics such as normal shadow fading, multipath time-varying fading, Doppler frequency shift, and sudden interference on the link.

[0014] (4) Insufficient communication countermeasure capability: In particular, the unmanned collaborative networking communication system is mainly used for strong enemy confrontation communication environment. The blue party's interference has a decisive impact on the spectrum availability and link accessibility of the red party's communication. The red party needs to have dynamic spectrum access capability to realize communication countermeasure functions such as frequency interception, blocking interference, and tracking interference. Summary of the Invention

[0015] Therefore, the purpose of the present invention is to provide a multi-frequency stereo networking system and a flexible network control method, to realize multi-frequency stereo networking based on a multi-channel radio frequency system, and to expand the networking capacity of unmanned formation collaboration; to adopt the idea of ​​numerical control separation and a dedicated network control unit for dynamic network management, to realize efficient and reliable online network control, to realize dynamic spectrum access based on collaborative spectrum sensing, and to improve networking flexibility and communication countermeasure capability; to realize highly reliable and low-overhead network control signaling transmission based on implicit diversity transmission, thereby realizing a highly reliable, low-overhead, robust and flexibly expandable multi-frequency stereo networking system and its flexible network control.

[0016] In order to achieve the above-mentioned object, the present invention provides a multi-frequency stereoscopic networking system, comprising:

[0017] Network management unit, used to store various storage tables required during network operation;

[0018] Flexible self-organizing network control unit, based on dedicated control channels and multi-hop simulcast technology for fast, low-overhead network signaling transmission, including control of initial networking and member management, random member access, dynamic resource allocation, cluster head selection and dynamic topology control, spectrum monitoring and adaptive frequency hopping;

[0019] The elastic self-organizing network protocol stack includes five layers of protocol stack: service layer, network layer, link layer, physical layer and transport layer.

[0020] The transmission channel of the transport layer is used for data transmission and subnet control of multiple subnets within a cluster, and the control channel is used for inter-cluster networking, relay transmission and full network control;

[0021] The physical layer uses digital signals to transmit in a flexible ad hoc network with or without human collaboration, realizing transmission waveforms and parallel processing of multiple signals;

[0022] The link layer uses a hybrid access control method compatible with synchronous / asynchronous modes for dynamic resource allocation and adaptive transmission.

[0023] Network layer: Adopting a hierarchical clustering approach for large-scale unmanned cluster networking, clustering algorithms and routing protocols, dynamic networking and multi-hop relay transmission, and expanding the network coverage of unmanned clusters;

[0024] Service layer: Uses software-defined networking to redefine transmission modes, routing policies, and traffic control online, and adapts the transmission mode of QoS service flows based on network load status.

[0025] Further preferably, the hierarchical clustering networking method of the network layer includes hierarchical clustering access control on one hand;

[0026] The hierarchical cluster access control includes sharing channel resources in a multi-frequency stereoscopic networking mode. The multi-frequency stereoscopic networking uses a time division / frequency division multiple access mode to support parallel transmission of multiple subnets. Among them, each subnet of the frequency division multiple access mode uses an independent frequency point or an orthogonal frequency hopping pattern for multi-frequency stereoscopic networking to reduce unpacked collisions between subnets and self-interference within the network; the time division multiple access mode is used to support the fair and effective allocation of shared channel resources within the subnet. Each node accesses the channel in units of time slots, shares the channel bandwidth in proportion, and supports its own business transmission.

[0027] Further preferably, the hierarchical clustering networking method of the network layer further includes hierarchical clustering topology control, and the hierarchical clustering topology structure includes:

[0028] Cluster head node: used to allocate and manage the time slot resources of each node in the subnet, and at the same time build inter-cluster subnets to realize inter-cluster data interaction;

[0029] Slave nodes are used to accept management from the cluster head node;

[0030] Parent node: If the node to be connected initiates access at any hop under the network node, the network node becomes the parent node of the node to be connected;

[0031] Child node: If a node to be connected initiates access at any hop under a networked node, the node to be connected becomes a child node of the networked node after joining the network;

[0032] Neighbor nodes: other nodes within one hop range of the current node, excluding parent nodes and child nodes, are defined as neighbor nodes.

[0033] The present invention also provides an elastic network control method, which is applied to the above-mentioned multi-frequency stereoscopic networking system, comprising:

[0034] S1, based on multi-frequency stereo networking, achieves multi-subnet parallel transmission through frequency division multiple access and time division multiple access;

[0035] S2, adopting the hierarchical clustering networking method, dynamically electing cluster head nodes and dividing task subnets;

[0036] S3, through flexible transmission control, adopts a collaborative interference detection method for interference detection and available frequency decision-making, supporting dynamic spectrum access;

[0037] S4. Flexible networking control is achieved through a multi-hop simulcast mechanism, broadcasting network signaling, and combining decoding and forwarding strategies with physical layer diversity reception technology to achieve full network coverage.

[0038] S5. The cluster head node performs dynamic network management, including opening / closing task subnets, member joining / leaving the network, dynamic allocation of time slots, and spectrum resource optimization.

[0039] Further preferably, in S3, the elastic transmission control includes:

[0040] Distributed spectrum sensing includes interference situation awareness and channel quality awareness; the interference situation awareness is used to perceive the current interference status of the target frequency point, which is expressed by noise power; the channel awareness is used to evaluate the demodulation environment of the channel, which is expressed by signal-to-noise ratio.

[0041] Perception information aggregation: When each slave node occupies a certain frequency point to transmit data through the sending time slot, it perceives the status information of each frequency point, quantizes the perception information of each frequency point, uses the quantized bit information to represent the frequency point status, and aggregates the acquired perception information to the cluster head node;

[0042] Spectrum sensing decision, after the cluster head node receives the frequency point sensing information aggregated from the nodes, it uses the OR merging criterion, AND merging criterion and K rank merging criterion to merge the sensing information;

[0043] Adaptive frequency hopping sequence update: After all the perception information is merged through the K-rank merging criterion, the availability of each frequency point is determined. All frequencies are represented by a 1-bit flag to indicate their status, 1 indicates that the frequency point is unavailable, and 0 indicates that the frequency point is available. The cluster head node broadcasts the updated decision information to all nodes in the system during the communication process. When a node hops, it determines the next frequency point to be hopped based on the hopping pattern and the frequency point status. When the next frequency point to be hopped in the hopping pattern is available, the next hopping will be performed at that frequency point. When the next frequency point to be hopped in the hopping pattern is unavailable, the next search for available hopping frequencies will continue. At this point, all nodes in the network can adaptively update the frequency hopping sequence in the network according to unified rules.

[0044] Further preferably, in S4, the multi-hop simulcast mechanism performs elastic networking control, and the broadcast network signaling includes the following steps:

[0045] S401, source node broadcast transmission: The source node generates an original information bit sequence, performs baseband modulation, spread spectrum or frequency hopping modulation, and radio frequency modulation in sequence, generates a radio frequency modulation signal, and transmits it through a broadcast channel; the radio frequency modulation signal is expressed as:

[0046]

[0047] Where c k (t), k∈{1,…,N} is a set of selected code group sequences {C N} is a pseudo-random code sequence randomly selected from c is the carrier frequency, s(t) is the digital baseband signal of length L;

[0048] S402, relay node cooperative transmission: After receiving the signal, the relay node adopts the decoding and forwarding strategy to send a copy of the signal in the orthogonal multiple access channel. The RF modulated signal sent by the relay node Rn is expressed as

[0049]

[0050] Where, represents the copy of the RF modulated signal sent by the nth cooperative relay node at the mth hop, c m (t), m∈{1,…,N} is a set of selected code group sequences {C N} is a pseudo-random code sequence randomly selected in order to ensure that the frequency hopping patterns of each hop are mutually exclusive; c is the carrier frequency, is the length L digital baseband signal sent by the nth cooperative relay node at the mth hop; n is the delay time of the nth signal.

[0051] S403, parallel signal detection: the relay node uses N parallel coherent detectors to demodulate the mixed received signal;

[0052] S404, parallel rate matching and soft demodulation: performing rate matching on the demodulated N signals and calculating soft demodulation results based on log-likelihood ratio (LLR);

[0053] S405, parallel channel estimation: calculating the signal-to-noise ratio of each signal;

[0054] S406, soft bit weighted combination: weighted combination of multiple soft bits according to a preset criterion;

[0055] S407, Viterbi demodulation: performing hard decision decoding based on the soft information output and recovering the original information through error checking;

[0056] S408, broadcast relay forwarding: controlling whether the relay node forwards based on the header relay level indicator (RI), including:

[0057] a) If the received relay level is the current level minus one, forward it in the next time slot;

[0058] b) If the received relay level is the same as the current level, stop forwarding;

[0059] c) If the received relay level is higher than the current level, the signal is discarded.

[0060] Further preferably, in S404, the log-likelihood ratio (LLR) is used to calculate the soft demodulation result using the following formula (9):

[0061]

[0062] Where b j,k is the kth bit of the jth symbol in the modulated signal, y j is the output signal of the j-th coherent detector, σ is the prior parameter used to determine the symbol distance, h is the channel coefficient, and s is the original signal.

[0063] Further preferably, in S406, the merging criterion is a linear weighted criterion or an exponential weighted criterion, wherein the exponential weighted criterion adopts the following formula (11):

[0064]

[0065] Where, LLR k are the kth soft bit of the i-th signal and the kth soft bit after merging, is the weighted combining coefficient of the i-th signal.

[0066] Further preferably, in S5, the cluster head node performs dynamic network management, including:

[0067] (1) Task subnet management: The central network control node distributes network control signaling on the control channel to achieve dynamic opening and closing of the task subnet;

[0068] When a task subnet is opened, an invitation-based network approach is used to distribute frequency sets, subnet transmission keys, access addresses, and initial resource allocation information to subnet members.

[0069] When the task subnet is closed, the active network exit method is adopted to reclaim the subnet frequency resources and add them to the frequency resource pool;

[0070] (2) Network member management: supports member joining, leaving and network switching, including:

[0071] Members within the plan automatically obtain network resources after completing identity authentication through pre-planned channels; members outside the plan perform identity authentication and resource requests through competitive channels, and resources are allocated after negotiation; when active / passive network exit occurs, the cluster head node reclaims communication resources through messages or timeout mechanisms;

[0072] (3) Network topology management: Optimize network architecture through dynamic clustering and routing management;

[0073] Dynamic clustering is based on task attributes and communication constraints, and a multi-hop clustering algorithm is used to select the best cluster head. Routing management includes intra-cluster table-driven routing and inter-cluster on-demand driven routing, supporting low-latency information distribution and cross-domain multi-hop path establishment, respectively.

[0074] (4) Network resource management: including dynamic allocation of time slots and management of available frequency sets;

[0075] Dynamic time slot allocation allocates bandwidth according to node service needs and priority; available frequency set management is based on distributed spectrum sensing, eliminating unavailable frequencies and updating the frequency set.

[0076] The multi-frequency stereo networking system and elastic network control method disclosed in this application have the following beneficial effects:

[0077] (1) A flexible self-organizing network system adapted for unmanned formation collaborative applications, consisting of a multi-channel RF front-end, a software radio platform, and a dedicated network control unit, which respectively implement multi-frequency stereo networking, multi-channel signal parallel processing, and flexible network control functions. The dedicated network control unit, supported by a dedicated control channel, supports dynamic network management during network operation, enabling members to join the network at will, route switching, dynamic time slot allocation, dynamic spectrum access, and other functions. It is flexible and adaptable to the demanding communication environments such as time-varying channels, dynamic links, and strong enemy confrontation required for unmanned formation collaborative combat applications.

[0078] (2) Flexible and autonomous hierarchical clustering networking method. During the operation of the elastic self-organizing network, the network control node can be independently elected to assume the resource management function of the task subnet without relying on network pre-planning.

[0079] (3) Agile and dynamic network management methods: Dynamic network management can be implemented during the operation of the elastic self-organizing network, and dynamic network management functions such as rapid reorganization, rapid resource scheduling, and rapid network access can be supported under the low-latency signaling broadcast mechanism.

[0080] (4) Efficient and reliable elastic networking control method. The elastic self-organizing network adopts a multi-hop simulcast mechanism for network control signaling transmission. With the support of multi-hop hidden diversity transmission technology, it has low latency, low overhead, and high reliability transmission characteristics, and supports efficient and reliable signaling broadcast.

[0081] (5) Elastic transmission control method for anti-interference and anti-destruction. The elastic self-organizing network adopts a dynamic spectrum access mechanism. With the support of collaborative spectrum sensing and online spectrum decision-making, it has adaptive frequency selection / hopping functions, and supports interference avoidance, cognitive spectrum access, anti-destruction and anti-interference functions under conditions of strong enemy confrontation. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 It is a structural diagram of the multi-frequency three-dimensional networking system in the present invention.

[0083] Figure 2 This is a timing diagram of the hierarchical clustered network access control proposed by the present invention.

[0084] Figure 3 Schematic diagram of the hierarchical clustering network topology of the present invention.

[0085] Figure 4 This is a flow chart of the dynamic spectrum access of the present invention.

[0086] Figure 5 This is a flowchart of node response during multi-hop simulcast transmission of the present invention. DETAILED DESCRIPTION

[0087] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0088] The idea of ​​the present invention is to realize multi-frequency stereo networking based on a multi-channel radio frequency system, expand the networking capacity of unmanned formation collaboration; adopt numerical control separation ideas and dedicated network control units for dynamic network management, and realize efficient and reliable online network control; realize dynamic spectrum access based on collaborative spectrum sensing, and improve networking flexibility and communication confrontation capability; realize highly reliable and low-overhead network control signaling transmission based on implicit diversity transmission, thereby realizing a highly reliable, low-overhead, robust and scalable multi-frequency stereo networking system that can be used for unmanned formation collaboration and its elastic network control.

[0089] like Figure 1 As shown, the multi-frequency three-dimensional networking system provided by an embodiment of the present invention is equivalent to setting up 5 layers and 3 planes, where the 3 planes are: management plane, control plane and data plane; the data plane is divided into 5 layers, namely, transport layer, physical layer, link layer, network layer and service layer. According to the specific function, the management plane is defined as a network management unit, the control plane is defined as an elastic self-organizing network control unit, and the data plane is an elastic self-organizing network protocol stack.

[0090] The network management unit is used to store various tables required during network operation. Non-volatile memory is used to store these tables, including member address tables, time and frequency resource tables, intra-cluster and inter-cluster routing tables, available and standby frequency tables, and operating mode configuration tables. These tables support dynamic configuration during network operation to adapt to the current operating environment of unmanned teaming and collaborative operations.

[0091] The elastic self-organizing network control unit performs fast and low-overhead network signaling transmission based on dedicated control channels and multi-hop simulcast technology, including control of initial networking and member management, random member access, dynamic resource allocation, cluster head selection and dynamic topology control, spectrum monitoring and adaptive frequency hopping, etc., so that the collaborative elastic self-organizing network with or without humans supports agile dynamic networking control functions.

[0092] The flexible ad hoc networking protocol stack uses software-defined radio and multi-channel radio frequency units to implement transmission networking functions, supports dynamic reconstruction of transmission waveforms and networking protocols, and includes a five-layer protocol stack:

[0093] a) Transport layer: Multi-channel radio frequency units are used to support transmission channel grouping and layered networking applications. Transmission channels are used for data transmission and subnet control within multiple clusters, while control channels are used for inter-cluster networking, relay transmission, and full network control.

[0094] b) Physical layer: Digital signal units are used to implement transmission waveforms and parallel processing of multiple signals for both manned and unmanned collaborative flexible ad hoc networks. These waveforms primarily include broadband anti-interference waveforms, covert anti-interference waveforms, interawareness-integrated waveforms, and directional beam control.

[0095] c) Link layer: This layer uses a hybrid access control method compatible with both synchronous and asynchronous modes, supports dynamic resource allocation and adaptive transmission, and supports QoS transmission services for services such as periodic measurement and control, broadband intelligence return, low-latency targeting, and sudden tactical coordination.

[0096] d) Network layer: A hierarchical clustering approach is used to support large-scale unmanned cluster networking. Clustering algorithms and routing protocols are used to support agile dynamic networking and multi-hop relay transmission, thereby expanding the network coverage of unmanned clusters.

[0097] e) Service layer: Use software-defined network mode to redefine transmission mode, routing strategy, and flow control online, and adapt the transmission mode of QoS service flow according to the network load status to better serve application layer service transmission.

[0098] The above-mentioned 5-layer 3-sided unmanned formation collaborative self-organizing network technology stack together constitutes the main function set of unmanned formation collaborative self-organizing network terminal equipment, such as elastic networking, adaptive transmission, comprehensive anti-interference and relative ranging, which can support typical unmanned formation collaborative combat applications such as measurement and control communication, formation collaboration, situation distribution and intelligence feedback.

[0099] The hierarchical clustering networking method of the network layer includes two aspects: hierarchical clustering access control and hierarchical clustering topology control;

[0100] in,

[0101] (1) Hierarchical Cluster Access Control

[0102] In terms of access control, layered clustering networking uses multi-frequency stereo networking (also known as stacked networking) to share channel resources and expand network throughput. Preferably, multi-frequency stereo networking uses time-frequency division multiple access (TFDMA) to support parallel transmission across multiple subnets. Each subnet in the FDMA system uses an independent frequency point or orthogonal frequency hopping pattern for multi-frequency stereo networking, ensuring no packet collisions between subnets and no self-interference within the network. TDMA is used to support fair and efficient allocation of shared channel resources within a subnet. Each node accesses the channel in time slots, sharing the channel bandwidth proportionally to support its own service transmission.

[0103] (2) Hierarchical clustering topology control

[0104] In terms of topology control, hierarchical clustering networking uses clustering networking to manage members and divide network responsibilities. The identities of nodes in the network are described as follows:

[0105] a) Cluster head node: It mainly manages the time slot resources of each node in the subnet and builds inter-cluster subnets to realize inter-cluster data interaction. It is divided into two types:

[0106] 1) Planning the cluster head node: Before the network is operational, the initialization parameters are determined, and network construction can be completed directly. The subnet within the cluster adopts the cluster head node planning method, directly designating a certain ad hoc network node as the cluster head node.

[0107] 2) Unplanned cluster head nodes: During network operation, these nodes can be promoted to central node members through a distributed algorithm. Inter-cluster subnets utilize unplanned cluster head nodes, with ad hoc nodes selecting the cluster head through a clustering algorithm. Preferably, this clustering algorithm utilizes adaptive clustering algorithms such as minimum ID, maximum node degree, and minimum mobility to optimize cluster head selection and maintain hierarchical network topology.

[0108] b) Slave nodes: All other nodes in the network that are not the cluster head node are called slave nodes and are managed by the cluster head node.

[0109] c) Parent node: If the node to be connected initiates access at a certain (one-hop) existing node, the existing node becomes the parent node of the node to be connected.

[0110] d) Child node: If a node to be connected initiates access to a certain (one-hop) existing node, the node to be connected becomes a child node of the existing node after joining the network.

[0111] e) Neighboring nodes: Nodes within one hop range of this node, excluding the parent node / child node, are called neighboring nodes.

[0112] The present application also provides an elastic network control method, which is applied to the above-mentioned multi-frequency stereo networking system, comprising:

[0113] S1, based on multi-frequency stereo networking, achieves multi-subnet parallel transmission through frequency division multiple access and time division multiple access;

[0114] S2, adopting the hierarchical clustering networking method, dynamically electing cluster head nodes and dividing task subnets;

[0115] S3, through flexible transmission control, adopts a collaborative interference detection method for interference detection and available frequency decision-making, supporting dynamic spectrum access;

[0116] S4. Flexible networking control is achieved through a multi-hop simulcast mechanism, broadcasting network signaling, and combining decoding and forwarding strategies with physical layer diversity reception technology to achieve full network coverage.

[0117] S5. The cluster head node performs dynamic network management, including opening / closing task subnets, member joining / leaving the network, dynamic allocation of time slots, and spectrum resource optimization.

[0118] In S3, the elastic transmission control method specifically includes the following:

[0119] (1) Distributed spectrum sensing

[0120] Spectrum sensing is implemented using a distributed sensing strategy, primarily consisting of interference situational awareness and channel quality awareness. Interference situational awareness only detects the interference situation at a specific frequency point, characterized by noise power. This is independent of the transmit and receive signal power and is less affected by the node's proximity effect. Channel quality awareness assesses the channel demodulation environment and can be characterized by the signal-to-noise ratio, which indicates the relationship between the current node's channel environment and demodulation status.

[0121] Interference situational awareness essentially involves measuring the interference conditions at each frequency point, which can be measured using the noise power at each frequency point. The noise power is the received signal power measured when no node in the network is transmitting data. To reduce the additional time slot overhead during spectrum sensing, each node switches to a receiving state after completing data transmission in the current time slot and measures the noise power at the current frequency point during the guard time at the end of the time slot.

[0122] In this measurement scheme, each node only measures the channel at the end of its own transmission time slot. Therefore, in each transmission time slot, only the channel status of the frequency corresponding to the previous transmission time slot is transmitted. After the time frame period ends, the master node collects the perception information of all nodes. When the number of nodes is small or the frequencies of different nodes in the time frame do not overlap, this part of the perception information is unique, and there is no duplication and merging of perception information. At this time, the performance advantage of distributed perception is not reflected; when the number of nodes is large or the frequencies of different nodes in the time frame overlap, the perception information of multiple nodes may correspond to the same frequency, and the perception information needs to be merged and processed.

[0123] When a node does not perform channel perception at the end of a transmitting time slot but performs perception at the end of all receiving time slots, the node can perceive the frequency state corresponding to the receiving time slot within one time frame period. At this time, the perception information collected and aggregated by the master node can better reflect the performance advantages of distributed perception. When a node performs interference detection at the end of a receiving time slot, it needs to avoid the signal duration of nodes in the network to prevent misjudgment of the interference state.

[0124] (2) Perception Information Convergence

[0125] After the node senses and obtains the status information of each frequency point, the status information of each frequency point needs to be aggregated to the master node, and the master node performs unified processing of the information of each frequency point.

[0126] To reduce the transmission overhead of slave node perception information, the perception information for each frequency point can be quantized, and the quantized bits can be used to represent the frequency point status. For a single frequency point, a single bit can be used to indicate whether the frequency point is normal. If the noise floor of the frequency point is detected to be above the set threshold, the frequency point at the node is considered to be interfered and unusable, and the frequency flag is set to 1; otherwise, it is set to 0. In this case, in a frequency hopping system that supports N frequency points, the node only needs to feedback N bits of perception information, which reduces the feedback overhead.

[0127] Using a single bit of feedback to represent frequency status results in a frequency being limited to two states: available or unavailable, which fails to effectively represent the interference level of the frequency. Therefore, the interference situation can be divided into multiple levels, with different noise floor ranges represented by different values ​​using multiple bits. For example, a 2-bit value can be used to represent the four interference levels of a frequency.

[0128] The frequency quality information measured by each node is quantized and added to the physical layer frame header. The quantization result is then reported to the master node for aggregation and decision-making. This requires allocating 4 bytes (or 8 bytes) of space in the frame header to transmit node spectrum sensing information. In the physical layer frame structure, a timeslot typically contains multiple subslots. The subslot header contains information such as the time-of-departure (TOD) and packet length. However, this information is repeated in subsequent subslots, so spectrum sensing information can be transmitted in the headers of subsequent subslots.

[0129] (3) Spectrum sensing decision

[0130] After receiving the frequency perception information aggregated from each node, the master node needs to combine the perception information to remove unusable frequencies in the current frequency hopping pattern or restore the normal use of previously removed frequencies.

[0131] Commonly used fusion decision mechanisms include OR merging criterion, AND merging criterion and K-rank merging criterion.

[0132] The rule of the OR merging criterion is: unless all sensing nodes determine that the frequency point is unavailable, the information fusion center will ultimately determine that the frequency point is available. That is, as long as there is one node that believes that the frequency point is available, the fusion center will determine that the frequency point is available.

[0133] The rule of the AND merging criterion is: unless all sensing nodes determine that the frequency point is available, the information fusion center will ultimately determine that the frequency point is unavailable. That is, as long as one node believes that the frequency point is unavailable, the fusion center will determine that the frequency point is unavailable.

[0134] The rule of the K-rank merging criterion is: a frequency point is considered available only when the number of nodes that can be used at that frequency point is greater than or equal to K (the value of K is generally not less than half of the number of network nodes); or in multi-bit quantization, when the quantization values ​​of all nodes in a certain frequency point are less than K (the K value here is related to the number of nodes and the quantization bit width; the larger the value, the greater the interference), the frequency point is considered available.

[0135] The K-rank merging criterion is more flexible. When K is removed from the maximum and minimum values, it becomes the AND and OR merging criteria respectively. In the design of this solution, the K-rank merging criterion is adopted, and the K value design can be flexibly configured.

[0136] The value of K is adaptively calculated based on the number of nodes in the network.

[0137] (4) Adaptive frequency hopping sequence update

[0138] After combining all the sensor information using the K-rank combining criterion, the availability of each frequency is determined. Each frequency is represented by a 1-bit flag: 1 indicates unavailable, and 0 indicates available. Therefore, in a frequency hopping system supporting N frequencies, the decision information consists of N bits.

[0139] During communication, the master node broadcasts updated decision information to all nodes in the system. To improve interaction efficiency and speed, decision information is sent and received at the physical layer, bypassing higher-layer processing. Therefore, frequency status information is added to the frame header. Therefore, in the system, slave nodes transmit their own frequency perception information, while the master node transmits decision status information for each frequency.

[0140] When a node hops, it determines the next frequency to hop to based on the hopping pattern and frequency status. If the next frequency in the hopping pattern is available, it hops to that frequency. If the next frequency in the hopping pattern is unavailable, it continues to search for an available frequency. At this point, all nodes in the network can adaptively update the frequency hopping sequence according to a unified rule. During the hopping pattern update process, different nodes may obtain frequency information at different times. All nodes in the network can update their frequency information uniformly after the time frame period ends.

[0141] In a distributed networking approach, frequency resources are fixedly allocated to transmission channels in traditional planar ad hoc networks, making it impossible to adaptively change frequencies during network operation. The flexible transmission control method described in this invention uses a collaborative interference detection method for interference detection and available frequency determination, supporting dynamic spectrum access during network operation.

[0142] In S4, the elastic networking control method includes the following steps:

[0143] (1) Source node broadcasts

[0144] The source node S generates the original information bit sequence b(t), which is then modulated by baseband to generate the symbol information s(t), which is then modulated by spread spectrum or frequency hopping to generate the spread spectrum signal, which is then modulated by the carrier to generate the RF modulated signal x(t) and sent out through the broadcast channel.

[0145] The source node S sends a radio frequency modulated signal through a broadcast channel. The modulation methods include baseband modulation, spread spectrum modulation, and radio frequency modulation:

[0146] -Baseband modulation can adopt common digital modulation methods such as phase shift keying (PSK), quadrature amplitude modulation (QAM), minimum shift keying (MSK), etc.

[0147] -Spread spectrum modulation can use bandwidth expansion modulation such as direct sequence spread spectrum (DSSS) and frequency hopping spread spectrum (FH) to resist signal interference within and outside the communication system;

[0148] -RF modulation is carrier modulation, which converts the intermediate frequency or baseband signal to a high frequency band and transmits it into the air through an antenna for radio signal propagation;

[0149] The expression of RF modulated signal x(t) is:

[0150]

[0151] Where c k (t), k∈{1,…,N} is a set of selected code group sequences {C N} is a pseudo-random code sequence randomly selected from c is the carrier frequency, s(t) is the digital baseband signal of length L, and the expression is as follows

[0152]

[0153] Where P is the normalized digital pulse energy, s l is the original information data, u(t) is the rectangular pulse function, T s is the pulse period.

[0154] (2) Relay node collaborative transmission

[0155] In the mth hop relay, the relay node R n After receiving the original information s(t) or relay information s`(t) on the broadcast channel, a decoding and forwarding strategy is adopted to send a copy of the information s on the orthogonal multiple access channel. n '(t), assisting other nodes to enhance the received signal. Relay node R n The expression of the transmitted RF modulated signal is:

[0156]

[0157] Where, represents the copy of the RF modulated signal sent by the nth cooperative relay node at the mth hop, c m (t), m∈{1,…,N} is a set of selected code group sequences {C N} is a pseudo-random code sequence randomly selected in order to ensure that the frequency hopping patterns of each hop are mutually exclusive; c is the carrier frequency, is the length L digital baseband signal sent by the nth cooperative relay node at the mth hop, and is expressed as follows

[0158]

[0159] Where P is the normalized digital pulse energy, s ’ l is the information data after decoding and forwarding, u(t) is the rectangular pulse function, T s is the pulse period.

[0160] According to the orthogonal characteristics of the code sequence of frequency hopping modulation, when any two cooperative relay signals with different phases meet in the air, their mutual correlation is close to zero, and the coherent demodulation between the multi-channel expansion / frequency hopping signals does not affect each other, forming a quasi-orthogonal multiple access channel.

[0161] In a virtual multi-antenna system based on coordinated multi-point relaying, if relay nodes use the same frequency and modulation scheme to transmit signals, the uncontrolled phase of the multipath channel will cause severe multipath interference, causing the interfering signals to merge and cancel each other. Therefore, the system described in the present invention uses spread-spectrum modulation for signal transmission and uses mutually orthogonal synchronization sequence codes to distinguish the transmitted signals of different relay nodes, thereby reducing signal interference within the system.

[0162] (3) Parallel signal detection

[0163] At the m+1th hop, the relay node R k Using N-way parallel coherent detectors for spread / frequency hopping demodulation, the received signal of each quasi-orthogonal multiple access path is expressed as

[0164]

[0165] Where, It represents the copy of the signal sent after decoding and forwarding by the nth cooperative relay node at the mth hop; is the Gaussian white noise on the propagation path of the nth cooperative relay node of the mth hop, which obeys the standard normal distribution N(0,1); c m (t), i∈{1,…,N} is a sequence from the selected code group set {C N}A pseudo-random code sequence randomly selected from ; is the channel coefficient from the nth node at the mth hop to the kth node at the m+1th hop. This coefficient is a constant within the propagation interval of one time slot. is the propagation delay from the nth node at the mth hop to the kth node at the m+1th hop.

[0166] At hop m+1, the relay node R k The received mixed signal expression is:

[0167]

[0168] At hop m+1, the relay node R k The jth (j∈{1,…,N}) coherent detector is used to perform coherent detection on the mixed signal received by N channels. The coherent integral expression is:

[0169]

[0170] Where c m (t) is the pseudo-random frequency hopping pattern of the m-th hop relay, τ n,j is the phase delay of the j-th coherent detector of the n-th node, and satisfies τ n,1 <…τ n,j <τ n,j+1 …<τ n,N , used to achieve arrival time priority multi-path signal separation.

[0171] s' l ,l∈{0,…L} is the lth valid information codeword forwarded by the mth hop relay decoding, is the output of the j-th coherent detector.

[0172] When the noise obeys the normal distribution, the arrival delay difference (Δτ n,j ) is greater than the frequency hopping pulse period (T p ), the output expression of the j-th coherent detector is:

[0173]

[0174] Under the condition of quasi-orthogonal delay channel, the decoding probability of the i-th coherent detector is only related to the transmitting power P of the transmitter and the channel coefficient Related.

[0175] (4) Parallel rate matching and soft demodulation

[0176] Rate matching and soft demodulation are performed on N received signals respectively. Rate matching refers to specifying the modulation order M and coding rate required for receiving demodulation according to the header; soft demodulation is a demodulation method based on the log-likelihood ratio (LLR), which requires calculating the received symbols to the set and The distances of all points are calculated and compared, and each consecutive M bits are mapped to a 2 on the constellation diagram. M The natural logarithm ratio of each bit is calculated based on the received information for bit decision:

[0177]

[0178] Where b j,k is the kth bit of the jth symbol in the modulated signal. σ is a priori parameter used to determine the symbol distance, h is the channel coefficient, and s is the original signal.

[0179] (5) Parallel channel estimation

[0180] Perform channel estimation on N signals to obtain the mean signal-to-noise ratio of each signal

[0181] {SNR1,SNR2,...,SNR m}, used for post-stage signal processing;

[0182] Optionally, the signal-to-noise ratio (SNR) in a digital communication system i ) is measured as follows:

[0183]

[0184] Where, SNR i is the mean signal-to-noise ratio of the i-th signal, E dwell is the pulse dwell energy mean, E idle is the average energy value of the pulse idle period, and K is the number of pulses occurring in the signal statistical period.

[0185] 6) Soft bit weighted combining

[0186] After soft demodulation, the soft bits of the m-channel received signals are weighted and combined according to a predefined combining criterion. The combining criterion can be linear weighting, exponential weighting, etc.

[0187] Optionally, the exponential weighting criterion is

[0188]

[0189] Where, LLR k are the kth soft bit of the i-th signal and the kth soft bit after merging, is the weighted combining coefficient of the i-th signal.

[0190] (7) Viterbi demodulation

[0191] Hard decision decoding is performed based on the soft information output (LLR) of soft bit demodulation. By tracing back the surviving path of the decoder, the coded sequence with the minimum Hamming distance to the received sequence is found. After Viterbi decoding, error checking is performed to obtain the original information b(t).

[0192] (8) Broadcast relay forwarding

[0193] The information sent by the m-th level relay node carries a header indication (RI). Incompletely, the header content contains the relay level of the current information. Based on the relay level indication (RI), broadcast relay forwarding processing is divided into three categories:

[0194] a) If the m+1 level node receives the broadcast information from the previous level relay node, it will choose to relay and forward it in the next time slot;

[0195] b) If the m+1 level node only receives broadcast information with the same relay level, it means that the information relay has reached the network boundary and no further forwarding is performed;

[0196] c) If a node at level m receives a broadcast message from a relay node at level m+1, it will no longer process the message, thus avoiding loop propagation that may cause decoding errors.

[0197] Traditional flat ad hoc networks use a competitive forwarding approach for signaling broadcasts. Each node forwards received signaling packets, which can easily lead to exponentially growing network overhead and create a broadcast storm problem. The elastic networking control method described in the present invention uses a multi-hop simulcast method for network signaling broadcasts. This method only requires k time slots (k is the maximum number of network hops) to broadcast signaling packets to the entire network, supporting low-latency, low-overhead signaling broadcasts. Furthermore, multi-hop simulcast incorporates physical layer diversity reception technology, enhancing the reliability of signaling transmission through diversity gain.

[0198] In a hierarchical clustered network architecture, the cluster head is responsible for network management of each subnet and inter-cluster communication. A flexible networking control method based on multi-hop simulcasting supports efficient and dynamic network management during cluster head network operation, including task subnet management, network membership management, network topology management, and network resource management.

[0199] (1) Task subnet management

[0200] The content of task subnet management includes the opening and closing of task subnets. The central network control node distributes network control signaling on the control channel, quickly distributes the network control information of the task subnet to relevant nodes, and supports agile dynamic networking.

[0201] Mission subnet activation is based on an invitation-based approach. After identity authentication, network control information, including the mission subnet's frequency set, subnet transmission key, access address, and initial resource allocation, is distributed to subnet members. Subnet members access services based on the initial resource allocation, and subsequently receive dynamic resource allocation based on demand.

[0202] The mission subnet is closed by actively exiting the network. After completing the unmanned collaborative combat mission, the mission subnet is closed, and the frequency resources of the mission subnet are recovered and added to the frequency resource pool.

[0203] (2) Network member management

[0204] Network member management mainly includes member network entry, network exit and network switching. The cluster head node distributes network control signaling on the control channel, exchanges identity authentication information with subnet members, and supports functions such as member network entry, late entry and active / passive network exit.

[0205] Member network access refers to the planned network access method for members. After completing the initial network synchronization, the planned network members will be authenticated on the pre-planned channel and automatically obtain network resources to support service transmission.

[0206] Late network entry refers to the way unplanned members join the network. After completing the initial network synchronization, such members need to perform identity authentication and resource request on the competition channel, and obtain network resources after negotiation to support business transmission.

[0207] Active / passive network exit refers to the subnet member actively notifying / abnormally interrupting service transmission after completing the task. The cluster head node obtains the specific member's network exit information through the message / timeout mechanism and reclaims the corresponding communication resources.

[0208] (3) Network topology management

[0209] Network topology management mainly includes dynamic clustering and routing management. Subnet members perform distributed cluster head election and routing maintenance, supporting hierarchical cluster network architecture and agile dynamic networking functions.

[0210] Dynamic clustering refers to the process in which network members, based on task attributes and communication constraints, use appropriate clustering algorithms to select the optimal cluster head during the operation of a task subnet. This cluster head then performs network topology and resource management functions. Alternatively, task-oriented subnets can employ multi-hop clustering algorithms to select a unique cluster head. Compared to single-hop clustering algorithms, this algorithm offers advantages such as simpler topology, better stability, and lower network overhead.

[0211] Routing management includes two routing tables: intra-cluster and inter-cluster routing, which respectively handle intra-region relay forwarding and inter-domain relay forwarding. Intra-cluster routing generally uses a table-driven routing strategy, supporting low-latency, high-frequency information distribution. Inter-cluster routing generally uses an on-demand routing strategy, establishing multi-hop transmission paths on demand for cross-domain collaboration, and handling bursty, low-frequency cross-domain collaborative information forwarding.

[0212] (4) Network resource management

[0213] Network resource management mainly includes dynamic allocation of time slots and management of available frequency sets. Cluster head nodes exchange network control information on the control channel to achieve optimal utilization of available network resources.

[0214] Dynamic time slot allocation builds on fixed time slot allocation by allocating shared time slots to each node's service needs. A member node sends a service transmission request, and the cluster head allocates bandwidth based on priority criteria and responds quickly on the control channel, enabling agile and rapid on-demand resource allocation.

[0215] Available frequency set management is based on distributed spectrum sensing, aggregating interference detection results to the cluster head node. After the cluster head node makes a fusion decision, it eliminates unavailable frequency points and quickly updates the frequency set on the control channel to achieve agile and fast cognitive spectrum access.

[0216] Based on the above-mentioned elastic transmission control method and elastic networking control method, the unmanned formation collaborative self-organizing networking system supports multi-frequency three-dimensional networking and dynamic network management during network operation, realizing an elastic transmission networking mechanism that is elastic, autonomous, agile, dynamic, efficient, reliable, anti-interference and anti-destruction, and supports robust and persistent networking of unmanned collaboration and networked collaborative combat applications such as collaborative reconnaissance, collaborative strike, collaborative guidance, and collaborative interference.

[0217] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A multi-frequency stereo networking system, characterized in that: include: Network management unit, used to store various storage tables required during network operation; Flexible self-organizing network control unit, based on dedicated control channels and multi-hop simulcast technology for fast, low-overhead network signaling transmission, including control of initial networking and member management, random member access, dynamic resource allocation, cluster head selection and dynamic topology control, spectrum monitoring and adaptive frequency hopping; The elastic self-organizing network protocol stack includes five layers of protocol stack: service layer, network layer, link layer, physical layer and transport layer; The transmission channel of the transport layer is used for data transmission and subnet control of multiple intra-cluster subnets, and the control channel is used for inter-cluster networking, relay transmission and full network control; The physical layer uses digital signals to transmit in a flexible ad hoc network with or without human collaboration, realizing transmission waveforms and parallel processing of multiple signals; The link layer uses a hybrid access control method compatible with synchronous / asynchronous modes for dynamic resource allocation and adaptive transmission. Network layer: Adopting a hierarchical clustering approach for large-scale unmanned cluster networking, clustering algorithms and routing protocols, dynamic networking and multi-hop relay transmission, and expanding the network coverage of unmanned clusters; Service layer: Uses software-defined networking to redefine transmission modes, routing policies, and traffic control online, and adapts the transmission mode of QoS service flows based on network load status.

2. The multi-frequency stereo networking system according to claim 1, characterized in that: The hierarchical clustering networking method of the network layer includes, on the one hand, hierarchical clustering access control; The hierarchical cluster access control includes sharing channel resources in a multi-frequency stereoscopic networking mode. The multi-frequency stereoscopic networking uses a time division / frequency division multiple access mode to support parallel transmission of multiple subnets. Among them, each subnet of the frequency division multiple access mode uses an independent frequency point or an orthogonal frequency hopping pattern for multi-frequency stereoscopic networking to reduce unpacked collisions between subnets and self-interference within the network; the time division multiple access mode is used to support the fair and effective allocation of shared channel resources within the subnet. Each node accesses the channel in units of time slots, shares the channel bandwidth in proportion, and supports its own business transmission.

3. The multi-frequency stereo networking system according to claim 1, characterized in that: The hierarchical clustering networking method of the network layer further includes hierarchical clustering topology control, wherein the hierarchical clustering topology structure includes: Cluster head node: used to allocate and manage the time slot resources of each node in the subnet, and at the same time build inter-cluster subnets to realize inter-cluster data interaction; Slave nodes are used to accept management from the cluster head node; Parent node: If the node to be connected initiates access at any hop under the network node, the network node becomes the parent node of the node to be connected; Child node: If a node to be connected initiates access at any hop under a networked node, the node to be connected becomes a child node of the networked node after joining the network; Neighbor nodes: other nodes within one hop range of the current node, excluding parent nodes and child nodes, are defined as neighbor nodes.

4. An elastic network control method, applied to the multi-frequency stereoscopic networking system according to any one of claims 1 to 3, characterized in that: include: S1, based on multi-frequency stereo networking, achieves multi-subnet parallel transmission through frequency division multiple access and time division multiple access; S2, adopting the hierarchical clustering networking method, dynamically electing cluster head nodes and dividing task subnets; S3, through flexible transmission control, adopts a collaborative interference detection method for interference detection and available frequency decision-making, supporting dynamic spectrum access; S4. Flexible networking control is achieved through a multi-hop simulcast mechanism, broadcasting network signaling, and combining decoding and forwarding strategies with physical layer diversity reception technology to achieve full network coverage. S5. The cluster head node performs dynamic network management, including opening / closing task subnets, member joining / leaving the network, dynamic allocation of time slots, and spectrum resource optimization.

5. The elastic network control method according to claim 4, characterized in that: In S3, the elastic transmission control includes: Distributed spectrum sensing includes interference situation awareness and channel quality awareness; the interference situation awareness is used to perceive the current interference status of the target frequency point, which is expressed by noise power; the channel awareness is used to evaluate the demodulation environment of the channel, which is expressed by signal-to-noise ratio. Perception information aggregation: When each slave node occupies a certain frequency point to transmit data through the sending time slot, it perceives the status information of each frequency point, quantizes the perception information of each frequency point, uses the quantized bit information to represent the frequency point status, and aggregates the acquired perception information to the cluster head node; Spectrum sensing decision, after the cluster head node receives the frequency point sensing information aggregated from the nodes, it uses the OR merging criterion, AND merging criterion and K rank merging criterion to merge the sensing information; Adaptive frequency hopping sequence update: After all the perception information is merged through the K-rank merging criterion, the availability of each frequency point is determined. All frequencies are represented by a 1-bit flag to indicate their status, 1 indicates that the frequency point is unavailable, and 0 indicates that the frequency point is available. The cluster head node broadcasts the updated decision information to all nodes in the system during the communication process. When a node hops, it determines the next frequency point to be hopped based on the hopping pattern and the frequency point status. When the next frequency point to be hopped in the hopping pattern is available, the next hopping will be performed at that frequency point. When the next frequency point to be hopped in the hopping pattern is unavailable, the next search for available hopping frequencies will continue. At this point, all nodes in the network can adaptively update the frequency hopping sequence in the network according to unified rules.

6. The elastic network control method according to claim 4, characterized in that: In S4, the multi-hop simulcast mechanism performs elastic networking control, and broadcast network signaling includes the following steps: S401, source node broadcast transmission: The source node generates an original information bit sequence, performs baseband modulation, spread spectrum or frequency hopping modulation, and radio frequency modulation in sequence, generates a radio frequency modulation signal, and transmits it through a broadcast channel; the radio frequency modulation signal is expressed as: Where c k (t), k∈{1,…,N} is a set of selected code group sequences {C N } is a pseudo-random code sequence randomly selected from c is the carrier frequency, s(t) is the digital baseband signal of length L; S402, relay node cooperative transmission: After receiving the signal, the relay node adopts the decoding and forwarding strategy to send a copy of the signal in the orthogonal multiple access channel. The RF modulated signal sent by the relay node Rn is expressed as Where, represents the copy of the RF modulated signal sent by the nth cooperative relay node at the mth hop, c m (t), m∈{1,…,N} is a set of selected code group sequences {C N } is a pseudo-random code sequence randomly selected in order to ensure that the frequency hopping patterns of each hop are mutually exclusive; c is the carrier frequency, is the length L digital baseband signal sent by the nth cooperative relay node at the mth hop; n is the delay time of the nth signal; S403, parallel signal detection: the relay node uses N parallel coherent detectors to demodulate the mixed received signal; S404, parallel rate matching and soft demodulation: performing rate matching on the demodulated N signals and calculating soft demodulation results based on log-likelihood ratio (LLR); S405, parallel channel estimation: calculating the signal-to-noise ratio of each signal; S406, soft bit weighted combination: weighted combination of multiple soft bits according to a preset criterion; S407, Viterbi demodulation: performing hard decision decoding based on the soft information output and recovering the original information through error checking; S408, broadcast relay forwarding: controlling whether the relay node forwards based on the header relay level indicator (RI), including: a) If the received relay level is the current level minus one, forward it in the next time slot; b) If the received relay level is the same as the current level, stop forwarding; c) If the received relay level is higher than the current level, the signal is discarded.

7. The elastic network control method according to claim 6, characterized in that: In S404, the log-likelihood ratio (LLR) is used to calculate the soft demodulation result using the following formula (9): Where b j,k is the kth bit of the jth symbol in the modulated signal, y j is the output signal of the j-th coherent detector, σ is the prior parameter used to determine the symbol distance, h is the channel coefficient, and s is the original signal.

8. The elastic network control method according to claim 4, characterized in that: In s406, the merging criterion is linear weighted or exponential weighted. The index weighting criterion adopts the following formula (11) Where, LLR k are the kth soft bit of the i-th signal and the kth soft bit after merging, is the weighted combining coefficient of the i-th signal.

9. The elastic network control method according to claim 4, characterized in that: In S5, the cluster head node performs dynamic network management, including: (1) Task subnet management: The central network control node distributes network control signaling on the control channel to achieve dynamic opening and closing of the task subnet; When a task subnet is opened, an invitation-based network approach is used to distribute frequency sets, subnet transmission keys, access addresses, and initial resource allocation information to subnet members. When the task subnet is closed, the active network exit method is adopted to reclaim the subnet frequency resources and add them to the frequency resource pool; (2) Network member management: supports member joining, leaving and network switching, including: Members within the plan automatically obtain network resources after completing identity authentication through pre-planned channels; members outside the plan perform identity authentication and resource requests through competitive channels, and resources are allocated after negotiation; when active / passive network exit occurs, the cluster head node reclaims communication resources through messages or timeout mechanisms; (3) Network topology management: Optimize network architecture through dynamic clustering and routing management; Dynamic clustering is based on task attributes and communication constraints, and a multi-hop clustering algorithm is used to select the best cluster head. Routing management includes intra-cluster table-driven routing and inter-cluster on-demand driven routing, supporting low-latency information distribution and cross-domain multi-hop path establishment, respectively. (4) Network resource management: including dynamic allocation of time slots and management of available frequency sets; Dynamic time slot allocation allocates bandwidth according to node service needs and priority; available frequency set management is based on distributed spectrum sensing, eliminating unavailable frequencies and updating the frequency set.

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