Fair distribution method for communication link carriers in aerospace information network

Abstract

The invention belongs to the technical field of wireless communication, and provides a fair distribution method for communication link carriers in an aerospace information network, which comprises the following steps of: establishing a double-layer multi-hop wireless communication network; the double-layer multi-hop wireless communication network comprises a UAF network and an LEO constellation, N UAV communication nodes are totally arranged in the UAF network, M access UAV nodes in the N UAV communication nodes communicate with a satellite to form M AoS links, and N-M terminal UAV nodes communicate with the access UAV nodes to form N-M UAV links; determining a fair carrier distribution model; according to the data rate matrix # imgabs0 # of the AoS link, a carrier allocation vector # imgabs1 # of the AoS link is determined; and according to the USIN and the rate # imgabs2 #, determining a UAV link carrier wave allocation vector # imgabs3 #. The invention aims at the problem of carrier distribution in the aerospace information network, more reasonably distributes carrier resources, and is beneficial to improving the resource utilization rate of the system, reducing the transmission delay and increasing the effectiveness of the system.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and particularly to a method for fair allocation of communication link carriers in an air-space information network. Background Art

[0002] Currently, the application of 5G communication in the Internet of Things (IoT) has achieved large-scale, high-rate, and low-latency communication - achieving a throughput 100 times that of 4G networks and an end-to-end latency one order of magnitude lower. Achieving the above goals requires a balance of spectral efficiency and latency among users. One of the key issues is the resource allocation problem of communication links, which is considered one of the bottleneck problems for the implementation of 5G-IoT.

[0003] The Ministry of Industry and Information Technology of China has issued the "Regulations on the Division of Radio Frequencies of the People's Republic of China" and allocated the 17.7 - 19.7 GHz frequency band for the use of satellite mobile communication earth stations. At the same time, Europe has also assigned this frequency band for the common use of satellite ground terminals and ground wireless links. Therefore, when considering spectral efficiency, there are multiple applications occupying the same frequency resources, and co-channel interference is also one of the important problems that must be solved. There is a resource allocation problem in USIN. This article considers how to improve network capacity, enhance spectral efficiency, and reduce co-channel interference under the spectrum resource sharing mode of 5G-IoT systems and satellite systems. Among them, two types of interference need to be considered, namely, the interference between the communication links of local UAF users and satellite communication links, and the interference between local UAF users.

[0004] Traditional strategies for reducing co-channel interference are mainly based on the directional emission of electromagnetic waves by complex antenna arrays. The disadvantage is that the hardware systems at the transmitting and receiving ends are extremely large. Carrier allocation technologies in 5G communication networks have been widely studied, and similar studies have also appeared in some cognitive satellite networks. However, for newly emerging hybrid networks similar to USIN, the research on carrier resource allocation is still relatively scarce. In practical applications, the two networks (UAF wireless communication network and LEO satellite network) must cooperate to allocate carriers to minimize the interference of one network on the other, and at the same time, all communication links must be able to be used to make the network more balanced. Summary of the Invention

[0005] Aiming at the defects in the prior art, the present invention provides a method for fair allocation of communication link carriers in an air-space information network to improve the resource utilization rate of the hybrid network, reduce the transmission latency, increase the system effectiveness, and more reasonably allocate carrier resources.

[0006] A method for fair allocation of communication link carriers in an air-space information network provided by the present invention includes: Establish a two - layer multi - hop wireless communication network; the two - layer multi - hop wireless communication network includes a UAF network and a LEO constellation. Among the N UAV communication nodes in the UAF network, M access UAV nodes communicate with satellites to form M AoS links, and N - M terminal UAV nodes communicate with access UAV nodes to form N - M UAV links; Determine a fair carrier allocation model; According to the data rate matrix of the AoS links determine the link with the minimum achievable rate among the unallocated AoS links and allocate the maximum rate carrier that can be obtained to the link to determine the carrier allocation vector of the AoS links ; According to the USIN sum rate determine the link with the minimum achievable rate among the unallocated UAV links and allocate the maximum rate carrier that can be obtained to the link to determine the carrier allocation vector of the UAV links ; where is the rate matrix considering the interference between UAV links, is the rate matrix considering the interference of AoS links on UAV links, and are weighting factors.

[0007] As can be seen from the above technical solutions, a method for fair carrier allocation of communication links in an air - space information network provided by the present invention optimizes the data rate of air - space links based on the max - min value, improving the fairness of link carrier allocation; on this basis, a carrier allocation algorithm with the goal of maximizing the system sum rate is proposed, considering the interference of air - space links on the UAV system and solving the interference problem in the carrier allocation process.

[0008] Optionally, the fair carrier allocation model is determined according to the data rate, specifically: ; is the data rate of the th UAV communication link, is the data rate of the th AoS data link; is an element in the carrier allocation vector indicating the carrier allocated to the th UAV communication link in the UAF system; is an element in the carrier allocation vector indicating the carrier allocated to the The carrier of the AoS link.

[0009] Optionally, before determining the AoS link carrier allocation vector it further includes: Establish an AoS link interference model, specifically: There is no interference between AoS links, but they are interfered by co-frequency UAV links. The interference on the m-th AoS link occupying the k-th carrier , where represents the set of UAV links that occupy the same carrier frequency as the m-th AoS link, is the gain of the receiving end of the AoS link with an offset angle of θ, represents the propagation loss between the transmitting end of the -th UAV link and the m-th AoS link when sharing the k-th carrier signal; The interference of the UAV link on the AoS link : , where is the satellite transmission signal power of the -th AoS link, is the satellite transmission antenna gain when θ = 0, represents the propagation loss when the -th AoS link occupies the k-th carrier signal, is the AoS link AWGN noise.

[0010] Optionally, the determination of the AoS link carrier allocation vector includes: S301. Initialize and , used to describe the already allocated AoS links, used to describe the already allocated carriers; S302. According to the already allocated carriers and links at the t-th iteration, delete the elements corresponding to the already allocated carriers and links from the rate matrix , and define ; S303. Find the column with the smallest element in , determine the AoS link that needs to be allocated a carrier, ; S304. Find the carrier that can achieve the maximum rate for the -th column of AoS links ; S305. Assign the th carrier to the th AoS link; S306. Update and for the next round t + 1; S307. Update the carrier allocation vector ; S308. Loop through steps S302 - S307 until a preset number of iterations is reached, and output .

[0011] Optionally, calculate Specifically: The preset interference matrix is , where each row represents the carrier frequency and each column represents the AoS link; Substitute element - by - element into the data rate to obtain ; where B is the bandwidth of each carrier band.

[0012] Optionally, before determining the UAV link carrier allocation vector , the method further includes: Establish an interference model for the UAV link, including interference between UAV links and interference from the AoS link to the UAV link. Specifically: The interference of the l - th UAV communication link occupying the k - th carrier is , where is the additive white Gaussian noise AWGN on the UAV link; represents the free - space propagation loss when the th UAV link uses the k - th carrier signal. The two represent the transmitter and receiver of this UAV link respectively; is the interference power on the l - th UAV communication link occupying the k - th carrier, which is the sum of the signal powers of all received co - frequency carriers , where represents the set of UAV links occupying the same carrier frequency as the l - th UAV link, is the signal power of the transmitter of the i - th UAV link, and represent the gains of the transmitter and receiver of the UAV link at the offset angle θ, denotes the direction offset angle between the transmitting antenna of the \(i\)-th link and the receiving antenna of the \(l\)-th link. denotes the free space propagation loss between the transmitting end of the \(i\)-th UAV link and the receiving end of the \(l\)-th UAV link when the two links share the \(k\)-th carrier signal. The interference of the AoS link on the UAV link is , where is the signal power of the transmitting end of the \(l\)-th UAV link, and are the gains of the transmitting and receiving ends of the UAV link when \(\theta = 0\), denotes the -th UAV link's propagation loss when occupying the \(k\)-th carrier signal, is the AWGN noise of the UAV link, then is , where denotes the set of UAV links that occupy the same carrier frequency as the -th AoS link, the satellite transmission signal power of the -th AoS link; is the transmitting end gain of the AoS link with an offset angle of θ , is the receiving end gain of the UAV link with an offset angle of \(\theta\), where denotes the -th link's direction offset angle between the transmitting antenna and the -th link's receiving antenna; denotes the -th AoS link's transmitting end and the -th UAV link's propagation loss when sharing the \(k\)-th carrier signal.

[0013] Optionally, the determination of the UAV link carrier allocation vector , includes: S401. Initialize and , used to describe the allocated UAF links; S402. According to the carriers and links already allocated at the \(t\)-th iteration, calculate and for the remaining unallocated links; S403. Calculate the sum rate ; S404. According to the carriers already allocated in the t-th iteration and the links , delete the elements corresponding to the already allocated carriers and links from , and define ; S405. Find the column with the smallest element in , determine the UAV link that needs to be allocated a carrier, ; S406. Find the carrier that can achieve the maximum rate for the UAV link in the th column ; S407. Allocate the th carrier to the th UAV link; S408. Update the UAF link set and the carrier set for the next round t + 1; S409. Update the carrier allocation vector ; S410. Loop through steps S402 - S09 until the numerical difference in two adjacent iterations is less than a preset threshold, and output .

[0014] Optionally, calculate Specifically: The interference between UAV links is calculated using , so there is , where each row element is the carrier frequency and each column element is the UAV link; Substitute the elements of into the data rate for calculation to obtain .

[0015] Optionally, calculate Specifically: The interference of the AoS link on the UAV link is calculated using , so there is , where each element represents the interference of the AoS link on the UAV link. Substitute the elements of into the data rate for calculation to obtain .

[0016] Adopting the above technical solution, the present application has the following beneficial effects: The present invention addresses the problem of carrier allocation in the space-air information network. In the space-air information network, space-air links and UAV formations share and reuse carriers, causing interference. By more reasonably allocating carrier resources, it is beneficial to improve the resource utilization rate of the system, reduce the transmission delay, and increase the system effectiveness. The present invention optimizes the data rate of the space-air link based on the max-min value, improving the fairness of link carrier allocation. On this basis, a carrier allocation algorithm with the goal of maximizing the system sum rate is proposed, considering the interference of the space-air link on the UAV system and solving the interference problem in the carrier allocation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts do not necessarily draw to scale.

[0018] Figure 1 Shows a schematic diagram of the USIN system model provided by an embodiment of the present invention; Figure 2 Shows a schematic diagram of a two-layer multi-hop wireless communication network provided by an embodiment of the present invention; Figure 3 Shows a flowchart of a method for fair allocation of communication link carriers in a space-air information network provided by an embodiment of the present invention; Figure 4 Shows a schematic diagram of the link rate distribution in the USIN network provided by an embodiment of the present invention; where Figure 4 (a) shows the distribution of the USIN link data rate under the max-min value carrier allocation algorithm, Figure 4 (b) shows the distribution of the USIN link data rate under the sum rate carrier allocation algorithm; Figure 5 Shows a schematic diagram of the link rate distribution in the USIN network provided by an embodiment of the present invention; Figure 6 Shows the variation of the delay with the K value when the USIN network in the embodiment of the present invention achieves fair carrier allocation. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following will describe in detail the embodiments of the technical solutions of the present invention in conjunction with the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, so they are only examples and cannot be used to limit the protection scope of the present invention. It should be noted that unless otherwise specified, the technical terms or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art to which the present invention belongs.

[0020] To realize the application of 5G-IoT in low-altitude flying unmanned aerial vehicles (UAVs) and build a wireless communication network for low-altitude UAV formations (UAFs), this embodiment proposes a space-air information network (UAF-Space Information Networks, USIN) model based on 5G Internet of Things technology and serving low-altitude UAFs. In the model, a low Earth orbit (LEO) satellite constellation is introduced, which is not only beneficial for areas not covered by ground wireless networks, but also can provide data offloading services for delay-tolerant networks. At the same time, it provides a backup communication link for emergency rescue communication, as Figure 1 shown.

[0021] The Ministry of Industry and Information Technology of China issued the "Regulations on the Division of Radio Frequencies of the People's Republic of China" and allocated the 17.7-19.8 GHz frequency band to satellite mobile communication Earth stations. At the same time, Europe also assigns this frequency band for common use by satellite ground terminals and ground wireless links. Therefore, when considering spectral efficiency, there are multiple applications occupying the same frequency resources, and co-channel interference is one of the important problems that must be solved. There is a resource allocation problem in USIN. This embodiment considers how to improve network capacity, enhance spectral efficiency, and reduce co-channel interference under the spectrum resource sharing mode of 5G-IoT systems and satellite systems. There are two types of interference to be considered, namely, the interference between the communication links of local UAF users and satellite communication links, and the interference between local UAF users.

[0022] Traditional strategies for reducing co-channel interference are mainly based on the directional emission of electromagnetic waves by complex antenna arrays, and the disadvantage is that the hardware systems at the transmitter and receiver ends are extremely large. In this embodiment, we solve the interference problem from the perspective of carrier allocation, and the spectral efficiency gain mainly comes from how to effectively pack a large number of communication links into the smallest number of carrier frequencies.

[0023] Carrier allocation technology in 5G communication networks has been widely studied, and similar research also appears in some cognitive satellite networks. However, for newly emerging hybrid networks such as USIN, the research on carrier resource allocation is relatively less. In practical applications, the two networks (UAF wireless communication network and LEO satellite network) must cooperate to allocate carriers to minimize the interference of one network on the other network, and at the same time, all communication links must be able to be used to make the network more balanced.

[0024] Based on this, this embodiment provides a method for fair allocation of communication link carriers in a space-air information network, including: S1. Establish a two-layer multi-hop wireless communication network.

[0025] It is assumed that there are N UAV nodes in the UAF in total, that is, n = 1, 2, 3, …, N. Each node has a two-way communication function. There are L UAV two-way links in total, that is, l = 1, 2, 3, …, L. Denote the set of outgoing links of each node as O(n) and the set of incoming links as I(n), that is, |O(n)| = |I(n)| = L.

[0026] In this embodiment, a two-layer multi-hop wireless communication network including a UAF network and a LEO constellation is constructed. The UAF network includes N UAV communication nodes, and M (M << N, m = 1, 2, 3, …, M) of them have satellite antennas, can transmit and receive satellite signals and receive data through the satellite network. That is, the number of air-to-space (AoS) links is M, and it also includes (N - M) ordinary UAV nodes; each satellite in the LEO constellation has 3 inter-satellite links, as Figure 2 shown.

[0027] Suppose there are K carrier resources available for allocation, with k = 1, 2, 3, …, K. The bandwidth of each carrier is B, that is, each carrier in the USIN has the same bandwidth. Generally speaking, L > K. Assume is the carrier allocation vector for the UAF, where the element is represents the carrier allocated to the l-th link in the UAF system. Since each link can only occupy one carrier resource and the same carrier may be occupied by different links, there will be frequency reuse and mutual interference among UAV links. Then there is (1) Meanwhile, assume is the carrier allocation vector for the AoS link, and there is an element

[0028] (2) The AoS link also operates in the single-carrier communication mode. Each link can only occupy one carrier resource. However, among all the M AoS links, this carrier cannot be occupied by other links, that is, there is no frequency reuse and mutual interference among AoS links.

[0029] Considering co-channel interference, the interference power on the l-th UAV communication link occupying the k-th carrier is the sum of the signal powers of all received co-channel carriers (3) where represents the set of UAV links that occupy the same carrier frequency as the -th UAV link, is the signal power of the transmitting end of the i-th UAV link, and denoted as the offset angle θ of the UAV link transmitter and receiver gains, denotes the direction offset angle between the transmitting antenna of the i-th link and the receiving antenna of the l-th link, denotes the free space propagation loss between the transmitting end of the i-th UAV link and the receiving end of the l-th UAV link when the two links share the k-th carrier signal.

[0030] The signal-to-interference-plus-noise ratio (SINR) of the l-th UAV communication link occupying the k-th carrier is (4) where is the additive white Gaussian noise (AWGN) on the UAV link. Compared with the interference signal power, the noise power is very small, so the noise is not considered in Equation (4). The AoS link will also be interfered by the co-frequency UAV link. The interference on the m-th AoS link occupying the k-th carrier is (5) where represents the set of UAV links that occupy the same carrier frequency as the m-th AoS link, is the receiver gain of the AoS link with an offset angle of θ, denotes the propagation loss between the transmitting end of the i-th UAV link and the m-th AoS link when sharing the k-th carrier signal. Similar to Equation (4), there is an interference from the UAV link to the AoS link

[0031] (6) where the -th AoS link satellite transmission signal power, is the satellite transmitting antenna gain when θ = 0, represents the propagation loss when the m-th AoS link occupies the -th carrier signal, is the AoS link AWGN noise. According to Equations (4) and (6), the data rate is (7) (8) Obtain and , that is, for the carrier allocation vector and Each element in is respectively operated according to formulas (7) and (8) to obtain vectors of the same length.

[0032] S2. Determine the fair carrier allocation model.

[0033] Furthermore, this embodiment proposes a fair carrier allocation scheme. The purpose is that all links in the network have similar throughputs, and then the following max-min optimization problem is obtained: (9) The optimization problem given by formula (9) can be solved by the exhaustive method, but using this method has exponential complexity and a huge amount of calculation when N, M, K, and L are large.

[0034] Therefore, in one embodiment, a sub-optimization method is also proposed: first solve the carrier allocation problem in the LEO satellite communication system, and then solve the carrier allocation problem of the UAF formation.

[0035] S3. According to the data rate matrix of the AoS link , determine the link with the minimum achievable rate among the unallocated AoS links , and allocate the maximum rate carrier that can be obtained to the link , and determine the AoS link carrier allocation vector .

[0036] First, consider allocating carrier resources in the space-air link, that is , , , then the AoS link carrier allocation can be based on the achievable rate of each link. However, different from the traditional sum rate maximization, the max-min problem in this embodiment needs to be solved by an effective estimation method. Preset matrix as (10) Each row in formula (10) represents the carrier frequency, and each column represents the AoS link. Substitute formula (10) into formula (8) (element-wise operation) for calculation to obtain the vector . Algorithm 1 adopts a serial carrier allocation strategy, that is, the link with the minimum achievable rate is allocated to the optimal available carrier frequency.

[0037] Step S3 specifically includes the following steps: S301. Initialize and , is used to describe the already allocated AoS links, is used to describe the already allocated carriers; S302. According to the already allocated carriers and links at the t-th iteration , delete the elements corresponding to the allocated carriers and links from the rate matrix , and define ; S303. Search for the column with the smallest element in , determine the AoS link that needs to be allocated a carrier ; S304. Find the carrier that can achieve the maximum rate for the column AoS link ; S305. Allocate the rd carrier to the th AoS link; S306. Update and for the next round t + 1; S307. Update the carrier allocation vector ; S308. Loop through steps S302 - S307 until the preset number of iterations is reached, and output .

[0038] The following specifically gives Algorithm 1.

[0039]

[0040] * In Algorithm 1 t is the number of iterations.

[0041] In addition to considering its own interference, the UAF carrier allocation also needs to consider the interference from the AoS link. Different from the traditional exhaustive search algorithm, this embodiment proposes a two-step sub-optimization algorithm to solve the NP-Hard problem of fair carrier allocation in the USIN network. The basic principle of UAV link carrier allocation is to try to allocate an empty carrier frequency to a new carrier, and to avoid multiple carriers multiplexing the same carrier as much as possible to reduce co-channel interference.

[0042] S4. According to USIN and the rate , determine the link with the minimum achievable rate among the unallocated UAV links , allocate the carrier with the maximum achievable rate to the link , and determine the UAV link carrier allocation vector . Among them, is the rate matrix considering the interference between UAV links, is the rate matrix considering the interference of the AoS link on the UAV link, and are the weighting factors.

[0043] The interference between UAV links can be calculated using Equation (4), and it is defined as (13) In Equation (13), the line number of each row represents the element carrier frequency, and the column number of each column represents the UAV link. Substituting Equation (13) into Equation (7) (operating element by element) for calculation, we get .

[0044] And there is an interference matrix

[0045] (14) where the matrix Each element represents the

[0046] (15) where The l th UAV link transmitter signal power, and is θ = 0, which are the gains of the UAV link transmitter and receiver. represents the l th UAV link's propagation loss when it occupies the k th carrier signal. N UAV is the UAV link AWGN noise, is (16) represents the set of UAV links that occupy the same carrier frequency as the l th AoS link. The i th AoS link satellite transmission signal power; is the AoS link transmitter gain with an offset angle of θ , is the UAV link receiver gain with an offset angle of θ , where represents the direction offset angle between the i th link's transmitting antenna and the l th link's receiving antenna; represents the i th AoS link transmitter and the l th UAV link, when sharing the k th carrier signal, the propagation loss. Then we have (17) Substitute Equation (14) into Equation (17) element by element (element - by - element operation) to obtain the matrix (18) Then, the carrier allocation algorithm proposed in this embodiment considers and , and applying the above Algorithm 1, the sum - rate is (19) where α and β are weighting factors. Without loss of generality, it can be set that α = β =0.5. Of course, it can also be set according to different emphases. For example α =0, β =1, or α =1, β =0.

[0047] Step S4 specifically includes the following steps: S401. Initialize and , which is used to describe the already - allocated UAF links; S402. According to the already - allocated carriers and links at the t - th iteration, calculate and for the remaining un - allocated links; S403. Calculate the sum - rate ; S404. According to the already - allocated carriers and links at the t - th iteration, delete the elements corresponding to the already - allocated carriers and links from , and define ; S405. Find the column in with the smallest element, and determine the UAV link that needs to be allocated a carrier, ; S406. Find the carrier that can achieve the maximum rate for the -th column UAV link; S407. Allocate the -th carrier to the -th UAV link; S408. Update the UAF link set and the carrier set for the next round t + 1; S409. Update the carrier allocation vector ; S410. Loop through steps S402 - S09 until the numerical difference in two iterations is less than a preset threshold, and output .

[0048] The following specifically gives Algorithm 2.

[0049]

[0050] The following conducts a simulation analysis on the method provided based on this embodiment. In a specific implementation, in the UAF system as Figure 1 shown, there are a total of 150 UAVs, among which 10 have satellite communication terminals and can communicate directly with satellites, thus forming 10 AoS links; there are 140 two - way links in the UAF. That is, each "user - layer UAV" can establish a link with a certain "access - layer UAV" and can then access the LEO satellite network and further access the USIN, as Figure 2 shown. In the network topology structure as Figure 2 shown, a mesh network is formed by 4 LEO satellites. Each LEO satellite can serve multiple UAVs to form a star network. Each UAV with an AoS link and several ordinary UAVs form a star network. The terminal layer is composed of 140 UAVs, that is, N = 150, M = 10, L = 140, and K = 20, B = 2 MHz. The parameters in the system model are shown in Table 1.

[0051] Table 1 Simulation parameters

[0052] In the case of K = 20 and B = 2 MHz, Figure 4 (a) gives the distribution of the data rate of the USIN link under the maximum - minimum carrier allocation algorithm, while Figure 4 (b) gives the distribution of the data rate of the USIN link under the sum - rate carrier allocation algorithm. From Figure 4 (a), it can be seen that the link rate is mainly distributed around [1.8, 2.2] Mbps. Under the maximum - minimum carrier allocation algorithm, the proportion of links in this interval reaches 80%; from Figure 4 (b), it can be seen that the link rate is mainly distributed around [1.6, 2.1] Mbps. Under the sum - rate carrier allocation algorithm, the proportion of links in this interval reaches 70.67%. The rate distributions under both algorithms roughly show a Gaussian distribution.

[0053] Figure 5 shows the change of the sum - rate of the USIN network with the value of the carrier number K. From Figure 5It can be found that the throughput of the two algorithms in this paper is increased by 18.50% and 27.06% respectively compared with the exhaustive algorithm.

[0054] Define the spectrum efficiency (SE) as (20) Table 2 gives the SE values of the UAV link, AoS link and USIN network. It can be seen that as the value of K increases, the spectrum efficiency in the network becomes smaller. This is because a larger number of carriers reduces the link bandwidth occupancy rate. Under the same circumstances, the spectrum resources are no longer so tense, and at the same time, the delay is reduced.

[0055] Table 2 Spectrum efficiency of USIN (bps / Hz)

[0056] Figure 6 shows the variation of the average delay of the USIN network with the change of the value of K when the carrier allocation reaches stability. As the number of carriers increases, the increase in alternative carrier resources reduces the queue waiting delay and data transmission delay. From Figure 6 it can be found that the delays of the two algorithms provided in this paper are reduced by 5.96% and 7.83% respectively compared with the exhaustive algorithm.

[0057] The simulation results verify the effectiveness of the algorithms. The data rates of the above two algorithms are increased by 18.50% and 27.06% respectively compared with the exhaustive algorithm, and the delays are decreased by 5.96% and 7.83%. To a large extent, it solves the interference problem in the case of carrier multiplexing, and provides ideas and reference for solving the resource allocation problem in such networks.

[0058] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0059] The above-described embodiments merely represent several implementation manners of the present application. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for fair allocation of communication link carriers in an air-space information network, characterized in that: include: Establishing a double-layer multi-hop wireless communication network; the double-layer multi-hop wireless communication network includes a UAF network and a LEO constellation, wherein the UAF network has a total of N UAV communication nodes, among which M access UAV nodes communicate with satellites to form M AoS links, and NM terminal UAV nodes communicate with access UAV nodes to form NM UAV links; Determining a fair carrier allocation model; According to the data rate matrix of AoS link , determine the link with the minimum achievable rate among the unassigned AoS links , for the link Allocate the maximum rate carrier that can be obtained and determine the AoS link carrier allocation vector ; Based on USIN and rate , determine the link with the minimum achievable rate among the unassigned UAV links , for the link Allocate the maximum rate carrier that can be obtained and determine the UAV link carrier allocation vector ;in, To consider the rate matrix of interference between UAV links, To consider the rate matrix of the AoS link interfering with the UAV link, and is the weighting factor.

2. The method according to claim 1, characterized in that The fair carrier allocation model is determined according to the data rate, specifically: ； in, For the The data rate of the UAV communication link, For the The data rate of the AoS data link; Assigning vectors to carriers The elements in the represent the first A carrier for UAV communication links; Assigning vectors to carriers The elements in the represent the first The carrier of the AoS link.

3. The method according to claim 2, characterized in that In determining the AoS link carrier allocation vector Previously, the method also included: Establish an AoS link interference model, specifically: There is no interference between AoS links, but they are interfered by the same-frequency UAV link, which interferes with the mth AoS link occupying the kth carrier. ， in represents the set of UAV links that occupy the same carrier frequency as the mth AoS link, is the gain at the receiving end of the AoS link with an offset angle of θ, Indicates The propagation loss between the transmitter of the 1st UAV link and the mth AoS link when sharing the kth carrier signal; Interference of UAV link to AoS link : ， in For the Satellite transmission signal power of AoS links, is the satellite transmitting antenna gain when θ=0, Indicates The propagation loss when the AoS link occupies the kth carrier signal, is the AWGN noise of the AoS link.

4. The method according to claim 3, characterized in that: Determining the AoS link carrier allocation vector ,include: S301. Initialization and , Used to describe the AoS link that has been allocated. Used to describe the allocated carrier; S302. According to the allocated carrier at the tth iteration and Link , from the rate matrix Delete the elements corresponding to the allocated carriers and links, and define ; S303. Search The smallest element in Column, determine the AoS link that needs to be assigned a carrier, ; S304. List AoS links to find the carrier that can achieve the maximum rate ; S305. The carrier is assigned to the AoS links; S306. Update the next round t+1 and ; S307. Update carrier allocation vector ; S308. Loop through steps S302-S307 until the preset number of iterations is reached, and output .

5. The method according to claim 4, characterized in that calculate Specifically: Presets The interference matrix is , where each row represents a carrier frequency and each column represents an AoS link; Will Element-wise data rate Obtained ; Where B is the bandwidth of each carrier frequency.

6. The method according to claim 5, characterized in that In determining the UAV link carrier allocation vector Previously, the method also included: The interference model of UAV links is established, including the interference between UAV links and the interference of AoS links to UAV links. Specifically: The interference of the lth UAV communication link occupying the kth carrier is ， in is the additive white Gaussian noise AWGN on the UAV link; Indicates The free space propagation loss of the k-th carrier signal in the UAV link is They represent the transmitting end and receiving end of the UAV link respectively; is the interference power on the lth UAV communication link occupying the kth carrier, which is the sum of the signal powers of all received carriers with the same frequency. ， in represents the set of UAV links occupying the same carrier frequency as the lth UAV link, is the signal power of the transmitter of the i-th UAV link, and The UAV link transmitter and receiver gains are expressed as offset angle θ, represents the directional deviation angle between the transmitting antenna of the ith link and the receiving antenna of the lth link, represents the free space propagation loss between the transmitter of the ith UAV link and the receiver of the lth UAV link when the two links share the kth carrier signal; The interference of AoS link to UAV link is: ， in is the signal power at the transmitting end of the lth UAV link, and are the UAV link transmitter and receiver gains when θ=0, Indicates The propagation loss when the k-th carrier signal is occupied by the UAV link, is the UAV link AWGN noise, Then ， in Indicates those occupying AoS links are a collection of UAV links with the same carrier frequency. No. Satellite transmission signal power for each AoS link; The offset angle is θ The AoS link transmitter gain, is the UAV link receiver gain at an offset angle of θ, where Indicates The link transmit antenna is connected to the Directional deviation angle of the link receiving antenna; Indicates The AoS link transmitter and Propagation loss when sharing the kth carrier signal between two UAV links.

7. The method according to claim 6, characterized in that Determining the UAV link carrier allocation vector ,include: S401. Initialization and , Used to describe the allocated UAF link; S402. According to the allocated carrier at the tth iteration and Link , calculated for the remaining unassigned links and ; S403. Calculation and rate ; S404. According to the allocated carrier at the tth iteration and Link ,from Delete the elements corresponding to the allocated carriers and links, and define ; S405. Search The smallest element in Column, determine the UAV link that needs to be assigned a carrier, ; S406. Column UAV link to find the carrier that can achieve the maximum rate ; S407. The carrier is assigned to the UAV links; S408. Update the UAF link set for the next round t+1 and carrier set ; S409. Update carrier allocation vector ; S410. Loop through steps S402-S09 until If the difference between the values ​​in two consecutive iterations is less than the preset threshold, the output .

8. The method according to claim 7, characterized in that calculate Specifically: Interference between UAV links using Calculated, we have , where the row number of each row represents the element carrier frequency and the column number of each column represents the UAV link; Will Element-wise data rate Calculate in .

9. The method according to claim 8, characterized in that calculate Specifically: The interference of AoS link to UAV link is Calculated, we have ， Each element represents the interference of the AoS link to the UAV link. Element-wise data rate Calculate in .

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