A blockchain-based multi-UAV spectrum dynamic authorization and interference coordination method

Abstract

The present invention discloses a method for dynamic authorization and interference coordination of multi-UAV spectrum based on blockchain, including: obtaining a set of available subcarriers in the current time slot; the UAV initiates a spectrum access request, and the associated base station calculates the sub-problem to obtain the frequency strategy of the UAV according to the number of available resources in the spectrum pool of the current time slot, combined with the mission requirements of the UAV and the interference threshold of other base stations; each base station reaches a consensus on the uploaded frequency strategy to verify whether there is a policy conflict. The present invention uses a spectrum dynamic authorization framework to enable base stations to share idle resources in the spectrum pool, UAVs apply for spectrum on demand, and each base station independently calculates the frequency strategy of its associated UAV, thereby reducing the computational complexity; at the same time, a consensus-based interference conflict elimination scheme is designed, and other nodes perform interference verification. When harmful interference exists, the base station recalculates the frequency strategy of the UAV according to the interference threshold of the disturbed base station, thereby controlling harmful interference to other base stations and ensuring the global consistency of the distributed strategy.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a blockchain-based multi-UAV spectrum dynamic authorization and interference coordination method. Background Art

[0002] In recent years, the civilian UAV market has developed rapidly, and the market share has increased sharply. It is widely used in power inspection, video surveillance, traffic control, emergency rescue and other fields. As the UAV market continues to expand, new requirements are put forward for its communication performance. However, the existing low-altitude available spectrum resources are seriously insufficient and it is difficult to support the communication needs of UAVs.

[0003] At the same time, due to the higher flying altitude of drones, they usually have a higher LOS path probability compared to ground UEs, which means that the drone's uplink signal will be received by more sites, and it will detect downlink signals from more sites, leading to more serious co-channel interference problems. In addition, in order to meet their own business needs, drones may have problems such as malicious occupation and illegal use, affecting low-altitude flight safety.

[0004] Blockchain is essentially a distributed data ledger that combines cryptography technology. Due to its distributed and decentralized characteristics, the data on the blockchain is tamper-proof and traceable. Blockchain can be used to dynamically share resources between different entities and make full use of resources. At the same time, the parameter information and frequency information of drones can be recorded on the blockchain to monitor the frequency usage of drones.

[0005] A Chinese patent with publication number CN115866768A discloses a blockchain-based method for implementing spectrum trading between drones and ground networks. The invention adopts an interference-based spectrum pricing model to reduce the weighted cumulative interference caused by drones to ground base stations in spectrum trading, fully utilizes the flexibility of drone base station deployment in spectrum trading, and implements a drone interference coordination mechanism based on a particle swarm algorithm, further reducing the interference caused by drones to ground base stations. The joint deployment of multiple drones further reduces the interference caused by drones to ground base stations compared to single drone deployment, and achieves a higher quality of service by designing parameter interference weight factors. However, the invention needs to rely on a spectrum pricing model, has a high degree of computational complexity, and is difficult to achieve dynamic authorization and interference coordination.

[0006] A Chinese patent with publication number CN114173419A discloses a spectrum allocation method for UAV-assisted Internet of Vehicles based on blockchain. The nodes in UNL are compared with their local candidate set. The local candidate set is the spectrum resource information set retained by the UAV in its local area. The resource information is updated in real time, and the idle spectrum is in this candidate set. If the requested channel is idle in the local candidate set, the transaction will get a vote; if the requested spectrum is not in the local candidate set, the node determines whether it is allowed to use it according to whether the requesting node uses this spectrum to cause harmful interference to itself; the node in UNL broadcasts the voting results back to the master node through the network, and the master node counts the votes of the transaction; when the request transaction obtains more than 50% of the votes, the transaction passes and the voting stops; if all nodes in UNL have completed the voting for the transaction or have not obtained more than 50% of the node votes after a certain time limit, the transaction is discarded and the master node resubmits other spectrum and power requests. Although the invention uses blockchain technology for spectrum management, the scheme does not involve interference coordination and management. The UAV in this invention acts as an auxiliary node to handle the spectrum requirements of the vehicles communicating with it, but its optimization problem does not take into account the interference caused to other nodes. The consensus mechanism mainly tests the tolerance of other nodes to the allocation strategy, which makes it difficult to obtain votes at nodes with low interference tolerance. Moreover, since the solution does not take the interference problem into consideration, it is not possible to dynamically adjust its allocation plan according to the tolerance of other nodes. Even if it is recalculated and submitted, there is no guarantee that the new allocation plan can effectively reduce interference, thereby affecting the overall network performance. Summary of the invention

[0007] The purpose of the present invention is to provide a blockchain-based multi-UAV spectrum dynamic authorization and interference coordination method. Through the spectrum dynamic authorization framework, base stations can share idle resources in the spectrum pool, UAVs apply for spectrum on demand, and each base station independently calculates the frequency usage strategy of its associated UAV, thereby reducing the calculation complexity; at the same time, a consensus-based interference conflict elimination scheme is designed, and other nodes perform interference verification to control harmful interference to other base stations and ensure the global consistency of distributed strategies.

[0008] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0009] A method for dynamic spectrum authorization and interference coordination of multiple unmanned aerial vehicles based on blockchain, the method comprising the following steps:

[0010] S1, ground base stations and drones complete registration in the blockchain network respectively, generate their own accounts and public-private key pairs; each ground base station regularly submits its own idle spectrum resource information of the current time slot to the resource pool, divides the total idle resources of all ground base stations in the current time slot by the minimum available subcarrier interval, and obtains the available subcarrier set of the current time slot;

[0011] S2: When the drone performs a mission, it initiates a spectrum access request on the blockchain network. The smart contract verifies the validity of all drone request signatures in the current time slot. After verification, the drone's channel gain is calculated based on the base station location and the drone's current location recorded on the chain. The associated base station of each drone is determined according to the base station association strategy, and the drone's spectrum request is sent to its associated base station. The associated base station calculates the optimization sub-problem based on the available resources in the spectrum pool in the current time slot, combined with the drone's mission requirements and the interference threshold of other base stations, to obtain the drone's frequency strategy, and then submits the frequency strategy to the blockchain.

[0012] S3, each base station reaches a consensus on the uploaded frequency strategy, verifies whether different base stations have allocated the same channel to the drones they serve, and whether there is a policy conflict; if there is no policy conflict, the base station votes to pass the frequency strategy, and after consensus on the chain to store the frequency strategy, it is broadcast to all base stations, and the drone communicates according to the frequency strategy, ending the process; if there is a policy conflict, the base station with the policy conflict verifies the interference threshold to determine whether to allow the reuse of the channel in the frequency strategy. When the interference is less than the interference threshold, the base station votes to pass the frequency strategy, and when the interference exceeds the interference threshold, the base station does not pass the frequency strategy;

[0013] S4, count the number of base stations that have passed the vote. If more than half of the nodes vote in favor, the frequency strategy is stored on the chain through consensus and broadcast to all base stations. The drone communicates according to the frequency strategy. Otherwise, the frequency strategy fails. The associated base station adjusts its optimization sub-problem based on the interference threshold of the base stations that have not voted in favor, that is, the interference threshold of the disturbed base station, recalculates the drone frequency strategy, submits the recalculated drone frequency strategy to the blockchain, and returns to step S3.

[0014] Furthermore, step S1 further includes the following steps:

[0015] S11, the ground base station is completed in the blockchain network, and the registration information of the base station is BS_Reg = {ID, loc, Ant, f c ,B,I th}, generate an account and a public-private key pair (PK, SK), the public key PK is used to encrypt information, and the private key SK is used for signing; ID represents the base station identifier, loc represents the geographical location of the base station, Ant represents the base station antenna parameters, and f crepresents the center frequency, B represents the bandwidth, and I th Indicates the interference threshold of the base station;

[0016] S12, the drone is registered in the blockchain network, and the drone registration information is UAV_Reg={ID U ,Type,Pmax,Ant U}, generate account and public-private key pair (PK U ,SK U ); ID U Indicates the drone's identifier; Type indicates the drone's equipment parameters; Pmax indicates the maximum transmit power; Ant U Indicates the parameters of the drone antenna;

[0017] S13, each base station periodically submits its own idle spectrum resource information in the current time slot to the resource pool. The total resources in the spectrum resource pool are the idle spectrum resources submitted by all base stations in the current time slot. The idle spectrum resource information is Fpro m ={ID m ,loc m ,sig m ,B m ,slot no}, the total idle resources of the current time slot are divided by the minimum available subcarrier ΔB interval, and the available subcarrier set of the current time slot is expressed as in, ID m Indicates the identity of the base station m that provides the spectrum, loc m represents the geographical location of base station m, sig m represents the digital signature of base station m, B m Indicates the idle spectrum resource bandwidth provided by base station m, slot no Indicates the current time slot number.

[0018] Furthermore, step S2 further includes the following steps:

[0019] S21, when the drone performs a task, it initiates a spectrum access request in the blockchain network; the spectrum access request is req n ={ID n ,loc n ,task n ,sig n ,slot no}; ID n Indicates the identity of the drone n applying for frequency use, loc n Indicates the current geographic location of drone n, task n represents the mission requirement of drone n, sig nRepresents the digital signature of drone n, slot no Indicates the current time slot number;

[0020] S22, the smart contract verifies all drone requests req in the current time slot n The validity of the signature, after verification, calculates the channel gain of the drone based on the base station location and the current location of the drone recorded on the chain, determines the associated base station of each drone based on the maximum signal-to-noise ratio, and sends the drone's spectrum request to its associated base station;

[0021] Among them, the channel gain calculation formula from drone n to base station m is:

[0022]

[0023] Where β0 represents the LoS channel power gain at a reference distance of 1m, α represents the path loss coefficient, and d n,m represents the Euclidean distance from drone n to base station m;

[0024] The information received at base station m is represented as MSG = { <Req n > m ,ID m}, <Req n > m Indicates the frequency application of all drones associated with base station m, ID m is the identifier of base station m;

[0025] S23, the associated base station calculates the optimization problem according to the available resources in the current time slot spectrum pool and the mission requirements of the drone to obtain the frequency strategy of the drone, and then submits the frequency strategy to the blockchain and waits for verification by other nodes; the frequency strategy information submitted by the base station is Stragy m ={ID m ,sig m , <stragy n > m ,slot no}; ID m Indicates the identity of base station m, sig m represents the digital signature of base station m, <stragy n > m represents the frequency strategy set of the drone associated with base station m, slot no Indicates the current time slot number; the UAV frequency strategy is stragy n ={ID n ,BS n ,channel n ,power n ,slotno}; ID n Indicates the identity of drone n, BS n Indicates the associated base station of drone n, channel n represents the distribution channel of drone n, power n Indicates the transmission power of drone n, slot no Indicates the current time slot number.

[0026] Furthermore, in step S3, if there is a policy conflict, the base station with the policy conflict verifies the interference threshold through the following formula to determine whether to allow the multiplexing channel:

[0027]

[0028] in, represents the set of all drones associated with base station m; x n,k ∈{0,1}, if drone n uses channel k, then x n,k =1, otherwise 0; p n,k represents the transmission power of human machine n on channel k, g n,m represents the channel gain from drone n to non-associated base station m, I th is the interference threshold, and k is the same occupied channel.

[0029] Furthermore, the multi-UAV spectrum dynamic authorization and interference coordination method further includes the following steps:

[0030] The management department completes the registration in the blockchain network, synchronously retrieves the recorded parameter information and frequency usage strategy of the drone from the blockchain, determines whether there is any illegal frequency usage behavior, and uploads the judgment result to the blockchain.

[0031] Furthermore, the multi-UAV spectrum dynamic authorization and interference coordination method further includes the following steps:

[0032] The management department receives complaint information sent by drones, which includes interference time, interference frequency band and flight area. The management department searches for relevant data on the chain based on the complaint information, makes interference judgments and coordination, and uploads the interference judgments and coordination results to the blockchain.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The blockchain-based multi-UAV spectrum dynamic authorization and interference coordination method of the present invention builds a trusted resource sharing platform through the blockchain network to solve the trust problem between different operators. Different subjects can perform dynamic resource management through the blockchain platform. At the same time, the parameter information and frequency information of the UAV are recorded on the chain, which can realize the effective supervision of frequency usage behavior. Considering the high computational complexity of the traditional resource allocation scheme, a distributed solution is adopted, and each base station solves the sub-problem independently, thereby improving the solution efficiency. There may be conflicts in the calculation sub-strategies between different base stations. By designing an interference conflict elimination scheme based on a consensus mechanism, the global consistency of the strategies obtained by the distributed solution of each base station is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flowchart of the blockchain-based multi-UAV spectrum dynamic authorization and interference coordination method of the present invention;

[0036] Figure 2 This is a flowchart of interference conflict elimination based on consensus mechanism;

[0037] Figure 3 This is a performance comparison diagram of the proposed solution of the present invention and the global solution;

[0038] Figure 4 This is a time consumption comparison chart between the proposed solution of the present invention and the global solution. DETAILED DESCRIPTION

[0039] The embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0040] See also Figure 1 The present invention discloses a multi-UAV spectrum dynamic authorization and interference coordination method based on blockchain, and the multi-UAV spectrum dynamic authorization and interference coordination method comprises the following steps:

[0041] S1, ground base stations and drones complete registration in the blockchain network respectively, generate their own accounts and public-private key pairs; each ground base station regularly submits its own idle spectrum resource information of the current time slot to the resource pool, divides the total idle resources of all ground base stations in the current time slot by the minimum available subcarrier interval, and obtains the available subcarrier set of the current time slot;

[0042] S2: When the drone performs a mission, it initiates a spectrum access request on the blockchain network. The smart contract verifies the validity of all drone request signatures in the current time slot. After verification, the drone's channel gain is calculated based on the base station location and the drone's current location recorded on the chain. The associated base station of each drone is determined according to the base station association strategy, and the drone's spectrum request is sent to its associated base station. The associated base station calculates the optimization problem based on the available resources in the spectrum pool in the current time slot and the drone's mission requirements to obtain the drone's frequency strategy, and then submits the frequency strategy to the blockchain.

[0043] S3, each base station reaches a consensus on the uploaded frequency strategy, verifies whether different base stations have allocated the same channel to the drones they serve, and whether there is a policy conflict; if there is no policy conflict, the base station votes to pass the frequency strategy, and after consensus on the chain to store the frequency strategy, it is broadcast to all base stations, and the drone communicates according to the frequency strategy, ending the process; if there is a policy conflict, the base station with the policy conflict verifies the interference threshold to determine whether to allow the reuse of the channel in the frequency strategy. When the interference is less than the interference threshold, the base station votes to pass the frequency strategy, and when the interference exceeds the interference threshold, the base station does not pass the frequency strategy;

[0044] S4, count the number of base stations that have passed the vote. If more than half of the nodes vote in favor, the frequency strategy is stored on the chain through consensus and then broadcast to all base stations. The drone communicates according to the frequency strategy. Otherwise, the frequency strategy fails. The associated base station adjusts its sub-problem (for example, using the interference threshold of the disturbed base station as a constraint item) and recalculates the drone frequency strategy according to the interference threshold of the disturbed base station (the base station that failed the vote), submits the recalculated drone frequency strategy to the blockchain, and returns to step S3.

[0045] The blockchain-based multi-UAV spectrum dynamic authorization and interference coordination method of the present invention includes four stages: initialization stage, frequency request and calculation strategy stage, consensus stage and supervision stage.

[0046] 1. Initialization phase

[0047] Step A1: The ground base station completes registration in the blockchain network and generates an account and a public-private key pair (PK, SK). The public key is used to encrypt information and the private key is used to sign, which makes the information tamper-proof and easy to verify.

[0048] The base station registration information is BS_Reg = {ID, loc, Ant, f c ,B,I th}, corresponding to the following contents:

[0049] 1) ID: base station identifier;

[0050] 2)loc: geographical location of the base station;

[0051] 3)Ant: base station antenna parameters;

[0052] 4)f c : center frequency;

[0053] 5) B: bandwidth;

[0054] 6)I th : Interference threshold of the base station.

[0055] Step A2: The drone is registered in the blockchain network and an account and public-private key pair (PK U ,SK U ).

[0056] The drone registration information is UAV_Reg={ID U ,Type,Pmax,Ant U}, corresponding to the following contents:

[0057] ID U : The drone’s identifier;

[0058] Type: equipment parameters of the drone;

[0059] Pmax: maximum transmit power;

[0060] Ant U : UAV antenna parameters.

[0061] Step A3: At each time period, each base station submits its idle spectrum resource information to the resource pool. The total resources in the spectrum resource pool are the idle spectrum resources submitted by all base stations in the current time slot. The total idle resources of the current time slot are divided by the minimum available subcarrier ΔB interval. The available subcarrier set of the current time slot is expressed as in,

[0062] Idle spectrum resource information is Fpro m ={ID m ,loc m ,sig m ,B m ,slot no}, corresponding to the following contents:

[0063] 1) ID m : The identity of the base station m providing the spectrum;

[0064] 2)loc m : The geographical location of base station m;

[0065] 3)sigm : Digital signature of base station m;

[0066] 4) B m : idle spectrum resource bandwidth provided by base station m;

[0067] 5) slot no : Current time slot number.

[0068] Spectrum Request and Calculation Strategy Phase

[0069] Step B1: When the drone performs a mission, it initiates a spectrum access request on the blockchain network.

[0070] Spectrum access request is req n ={ID n ,loc n ,task n ,sig n ,slot no}; respectively correspond to the following contents:

[0071] 1) ID n : The identity of the drone n applying for frequency use;

[0072] 2)loc n : The current geographic location of drone n;

[0073] 3)task n : Mission requirements of drone n;

[0074] 4)sig n : Digital signature of drone n;

[0075] 5) slot no : Current time slot number.

[0076] Step B2, the smart contract verifies all drone requests req in the current time slot n The validity of the signature,after verification is passed, the channel gain of the drone is calculated,based on the base station location and the current location of the drone,,and the associated base station of each drone is determined according to the base station,association strategy such as the maximum signal-to-noise ratio, and the spectrum request of the drone is,sent to its associated base station.

[0077] Among them, the channel gain calculation formula from drone n to base station m is:

[0078]

[0079] Where β0 represents the LoS channel power gain at a reference distance of 1m, α represents the path loss coefficient, and d n,m Represents the Euclidean distance from UAV n to base station m.

[0080] In step B2, the information received at base station m is represented as MSG = {<Req n > m ,ID m}, <Req n > m Indicates the frequency application of all drones associated with base station m, ID m is the identifier of base station m.

[0081] Since the resource allocation problem of drones is usually complex and difficult to solve, the traditional solution is usually to solve the optimization problem by a master node to obtain the frequency strategy of all drones. In order to reduce the computational complexity, a distributed solution is proposed. The frequency strategy of drones is calculated independently by their associated base stations. Compared with the global optimization problem, the sub-optimization problem is first reduced in complexity and only involves base station-associated drones. In order to control the interference to other base stations under the global information location, the optimization sub-problem constraints of each base station should include interference control items, that is, the cumulative interference on each channel is less than a certain threshold.

[0082] In step B3, the associated base station calculates the optimization problem based on the number of available resources in the current time slot spectrum pool and the mission requirements of the drone to obtain the frequency utilization strategy of the drone, and then submits the strategy to the blockchain and waits for verification by other nodes.

[0083] The frequency strategy information submitted by the base station is Stragy m ={ID m ,sig m , <stragy n > m ,slot no}, corresponding to the following contents:

[0084] 1) ID m : The identity of base station m;

[0085] 2)sig m : Digital signature of base station m;

[0086] 3) <stragy n > m : The frequency strategy collection of the drone associated with base station m;

[0087] 4) slot no : Current time slot number.

[0088] The frequency strategy of drone is stragy n ={ID n ,BS n ,channel n ,powern ,slot no}, corresponding to the following contents:

[0089] 1) ID n : The identity of drone n;

[0090] 2)BS n : The associated base station of drone n;

[0091] 3)channel n : Allocation channel of UAV n;

[0092] 4) power n : The transmission power of UAV n;

[0093] 5) slot no : Current time slot number.

[0094] 3. Consensus Phase

[0095] Since conflicts may occur when each base station calculates its strategy independently, the present invention provides an interference conflict elimination method based on a consensus mechanism, that is, when each base station uploads a strategy, other base stations verify the feasibility of the strategy, such as whether the interference threshold is met, see Figure 2 , the specific steps of the consensus phase are as follows:

[0096] Step C1: Each base station uploads its own calculated strategy to the chain for consensus, and other nodes verify whether there is a policy conflict, that is, whether different base stations allocate the same channel to the drones they serve:

[0097] Step C2: If there is no conflict in the policy, the node votes for the policy. If there is a conflict in the policy, the node with the conflicting policy determines whether to allow the channel to be reused by verifying the interference threshold. The verification expression is as follows:

[0098]

[0099] in, represents the set of all drones associated with base station m, x n,k ∈{0,1}, if drone n uses channel k, then x n,k =1, otherwise 0. n,k represents the transmission power of human machine n on channel k, g n,m represents the channel gain from drone n to non-associated base station m, I th is the interference threshold, and k is the same channel occupied. When the interference is less than the threshold, the node votes for the strategy. When the interference exceeds the threshold, the node does not vote for the strategy.

[0100] Step C3: Only when more than half of the nodes vote in favor, the strategy is broadcast to all nodes after being recorded on the chain through consensus, and the drone communicates according to the frequency strategy. If the drone subsequently violates the frequency usage rules, the drone can be dealt with according to the frequency usage rules recorded on the chain.

[0101] In step C4, if more than half of the nodes vote, the strategy is not passed. The base station needs to verify the ground base stations whose interference exceeds its threshold, adjust its optimization problem according to the interference threshold of the interfered base station, recalculate the UAV frequency strategy, and re-execute the entire process. This consensus solution can effectively control the interference of UAVs to other non-associated base stations and ensure the global consistency of decision-making.

[0102] IV. Supervision Stage

[0103] Since the parameter information and frequency strategy of drones are recorded on the blockchain, the management department can synchronize the on-chain data for analysis to determine whether there is any illegal frequency usage. In addition, other drones can also complain about illegal behaviors, and the complaint information includes interference time, interference frequency band and area. The management department can find relevant data on the chain based on the complaint information, make interference judgments and coordination, and the judgment and coordination results are uploaded to the blockchain.

[0104] In the global solution, the present invention uses a master node to solve the global optimization problem. Figure 3 and Figure 4 The simulation results show that the proposed scheme has a slight performance loss compared to the global scheme, but greatly reduces the complexity of the algorithm. When the number of base stations increases, the time consumption of the traditional scheme increases greatly, but the proposed scheme has basically unchanged time consumption because each base station solves the frequency strategy of the drones it serves.

[0105] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0106] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0107] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0108] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0109] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0110] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A blockchain-based multi-UAV spectrum dynamic authorization and interference coordination method, characterized in that: The multi-UAV spectrum dynamic authorization and interference coordination method comprises the following steps: S1, ground base stations and drones complete registration in the blockchain network respectively, generate their own accounts and public-private key pairs; each ground base station regularly submits its own idle spectrum resource information of the current time slot to the resource pool, divides the total idle resources of all ground base stations in the current time slot by the minimum available subcarrier interval, and obtains the available subcarrier set of the current time slot; S2: When the drone performs a mission, it initiates a spectrum access request on the blockchain network. The smart contract verifies the validity of all drone request signatures in the current time slot. After verification, the drone's channel gain is calculated based on the base station location and the drone's current location recorded on the chain. The associated base station of each drone is determined according to the base station association strategy, and the drone's spectrum request is sent to its associated base station. The associated base station calculates the optimization sub-problem based on the available resources in the spectrum pool in the current time slot, combined with the drone's mission requirements and the interference threshold of other base stations, to obtain the drone's frequency strategy, and then submits the frequency strategy to the blockchain. S3, each base station reaches a consensus on the uploaded frequency strategy, verifies whether different base stations have allocated the same channel to the drones they serve, and whether there is a policy conflict; if there is no policy conflict, the base station votes to pass the frequency strategy, and after consensus on the chain to store the frequency strategy, it is broadcast to all base stations, and the drone communicates according to the frequency strategy, ending the process; if there is a policy conflict, the base station with the policy conflict verifies the interference threshold to determine whether to allow the reuse of the channel in the frequency strategy. When the interference is less than the interference threshold, the base station votes to pass the frequency strategy, and when the interference exceeds the interference threshold, the base station does not pass the frequency strategy; S4, when the strategy is not passed, the associated base station adjusts its optimization sub-problem according to the interference threshold of the base station that did not pass the vote, recalculates the drone frequency strategy, submits the recalculated drone frequency strategy to the blockchain, and returns to step S3.

2. The blockchain-based multi-UAV spectrum dynamic authorization and interference coordination method according to claim 1 is characterized in that: Step S1 further comprises the following steps: S11, the ground base station is completed in the blockchain network, and the registration information of the base station is BS_Reg = {ID, loc, Ant, f c ,B,I th }, generate an account and a public-private key pair (PK, SK), the public key PK is used to encrypt information, and the private key SK is used for signing; ID represents the base station identifier, loc represents the geographical location of the base station, Ant represents the base station antenna parameters, and f c represents the center frequency, B represents the bandwidth, and I th Indicates the interference threshold of the base station; S12, the drone is registered in the blockchain network, and the drone registration information is UAV_Reg={ID U ,Type,Pmax,Ant U }, generate account and public-private key pair (PK U ,SK U ); ID U Indicates the drone's identifier; Type indicates the drone's equipment parameters; Pmax indicates the maximum transmit power; Ant U Indicates the parameters of the drone antenna; S13, each base station periodically submits its own idle spectrum resource information in the current time slot to the resource pool. The total resources in the spectrum resource pool are the idle spectrum resources submitted by all base stations in the current time slot. The idle spectrum resource information is Fpro m ={ID m ,loc m ,sig m ,B m ,slot no }, the total idle resources of the current time slot are divided by the minimum available subcarrier ΔB interval, then the available subcarrier set of the current time slot is expressed as in, ID m Indicates the identity of the base station m that provides the spectrum, loc m represents the geographical location of base station m, sig m represents the digital signature of base station m, B m Indicates the idle spectrum resource bandwidth provided by base station m, slot no Indicates the current time slot number.

3. The blockchain-based multi-UAV spectrum dynamic authorization and interference coordination method according to claim 1 is characterized in that: Step S2 further comprises the following steps: S21, when the drone performs a task, it initiates a spectrum access request in the blockchain network; the spectrum access request is req n ={ID n ,loc n ,task n ,sig n ,slot no }; ID n Indicates the identity of the drone n applying for frequency use, loc n Indicates the current geographic location of drone n, task n represents the mission requirement of drone n, sig n Represents the digital signature of drone n, slot no Indicates the current time slot number; S22, the smart contract verifies all drone requests req in the current time slot n The validity of the signature, after verification, calculates the channel gain of the drone based on the base station location and the current location of the drone recorded on the chain, determines the associated base station of each drone based on the maximum signal-to-noise ratio criterion, and sends the drone's spectrum request to its associated base station; Among them, the channel gain calculation formula from drone n to base station m is: Where β0 represents the LoS channel power gain at a reference distance of 1m, α represents the path loss coefficient, and d n,m represents the Euclidean distance from drone n to base station m; The information received at the base station m is represented as MSG = {<Req n > m ,ID m }, <Req n > m Indicates the frequency application of all drones associated with base station m, ID m is the identifier of base station m; S23, the associated base station calculates the optimization problem according to the available resources in the current time slot spectrum pool and the mission requirements of the drone to obtain the frequency strategy of the drone, and then submits the frequency strategy to the blockchain and waits for verification by other nodes; the frequency strategy information submitted by the base station is Stragy m ={ID m ,sig m , <stragy n > m ,slot no }; ID m Indicates the identity of base station m, sig m represents the digital signature of base station m, <stragy n > m represents the frequency strategy set of the drone associated with base station m, slot no Indicates the current time slot number; the UAV frequency strategy is stragy n ={ID n ,BS n ,channel n ,power n ,slot no }; ID n Indicates the identity of drone n, BS n Indicates the associated base station of drone n, channel n represents the distribution channel of drone n, power n Indicates the transmission power of drone n, slot no Indicates the current time slot number.

4. The blockchain-based multi-UAV spectrum dynamic authorization and interference coordination method according to claim 1 is characterized in that: In step S3, if there is a conflict in the policies, the base station with the conflicting policies verifies the interference threshold through the following formula to determine whether to allow the multiplexing channel: in, represents the set of all drones associated with base station m; x n,k ∈{0,1}, if drone n uses channel k, then x n,k =1, otherwise 0; p n,k represents the transmission power of human machine n on channel k, g n,m represents the channel gain from drone n to non-associated base station m, I th is the interference threshold, and k is the same occupied channel.

5. The blockchain-based multi-UAV spectrum dynamic authorization and interference coordination method according to claim 1 is characterized in that: The multi-UAV spectrum dynamic authorization and interference coordination method also includes the following steps: The management department completes the registration in the blockchain network, synchronously retrieves the recorded parameter information and frequency usage strategy of the drone from the blockchain, determines whether there is any illegal frequency usage behavior, and uploads the judgment result to the blockchain.

6. The blockchain-based multi-UAV spectrum dynamic authorization and interference coordination method according to claim 5 is characterized in that: The multi-UAV spectrum dynamic authorization and interference coordination method also includes the following steps: The management department receives complaint information sent by drones, which includes interference time, interference frequency band and flight area. The management department searches for relevant data on the chain based on the complaint information, makes interference judgments and coordination, and uploads the interference judgments and coordination results to the blockchain.

Images