CN114301794B - LEOMEO double-layer satellite constellation-oriented interlayer link topology design method - Google Patents
LEOMEO double-layer satellite constellation-oriented interlayer link topology design method Download PDFInfo
- Publication number
- CN114301794B CN114301794B CN202111507541.XA CN202111507541A CN114301794B CN 114301794 B CN114301794 B CN 114301794B CN 202111507541 A CN202111507541 A CN 202111507541A CN 114301794 B CN114301794 B CN 114301794B
- Authority
- CN
- China
- Prior art keywords
- satellite
- link
- interlayer
- time slot
- layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Landscapes
- Radio Relay Systems (AREA)
Abstract
The invention belongs to the technical field of satellite network design, and discloses an interlayer link topology design method for LEOMEO double-layer satellite constellation, which comprises the following steps: constructing a double-layer satellite network system, and establishing a performance evaluation index; based on a virtual topological scheme, a topological structure of each time slot is modeled by adopting time slicing, a 0-1 integer linear programming scheme based on time evolution is designed, and a topological sequence of an interlayer link is designed under the constraints of a visible relation, antenna transmitting power and the number of interlayer antennas. According to the method, by designing an evaluation model of interlayer information bearing capacity and topological stability of a multilayer constellation, the total interlayer link rate is maximized based on interlayer topological time evolution, the topological performance under flexible antenna parameter configuration is explored, the connection relation between a low-orbit satellite and a high-orbit satellite is optimized, the interlayer topological stability and the interlayer information bearing capacity are improved, the interlayer link stability is enhanced, the topological stability is guaranteed, and the network topology maintenance cost and the switching frequency of an interlayer satellite antenna are reduced.
Description
Technical Field
The invention belongs to the technical field of satellite network design, and particularly relates to an LEOMEO double-layer satellite constellation-oriented interlayer link topology design method.
Background
At present, a double-layer satellite network consists of a high orbit constellation and a low orbit constellation, and a connection scheme of inter-satellite links between the two layers forms an interlayer topology. The differentiated orbital heights result in differentiated motion periods for the two satellites. For two satellites with different orbital periods, a permanent visible inter-layer link may be formed only if the orbital radii of both satellites are greater than 2.14 times the radius of the earth. Thus, the LEO/MEO constellation does not qualify for the construction of permanent inter-layer links, subject to earth shadowing. Over time, the visual range between two stars can be shielded by the earth, so that frequent link switching and disconnection are caused, and the topological time-varying property is strong. The current interlayer topology design scheme for the double-layer satellite network is mainly the interlayer topology design based on a virtual topology model.
The virtual topological model divides the orbit period T of the satellite network into n time slots { [ T ] 0 ,t 1 ),[t 1 ,t 2 ),…,[t n-1 ,t n ) H, where t 0 ＝0,t n And (T). The topology of the network within each time slot can be considered as a static topology, the change of topology only occurring at the switching instant t of the time slot 1 ,t 2 ,…t n-1 }. Due to the predictability of the satellite motion, all topological switching time points and node connection relations in each time slot can be calculated in advance. In consideration of the high dynamic characteristics of the inter-layer links, the virtual topology model can model the inter-layer link change into a time evolution sequence of a plurality of static graphs, characterize the inter-layer topology at any moment by the static graphs corresponding to the time slots, characterize the dynamic change of the inter-layer links by the time evolutions of the adjacent time slots, and accurately describe the inter-layer topology.
Based on a virtual topology model, the topology design schemes of the inter-layer links are mainly divided into two types: one type aims at guaranteeing the QoS of the service and enhancing the information transmission capability of the network. The prior art provides a virtual topology grouping strategy, LEO satellites are divided into groups, each group is allocated with one MEO satellite as a Leader, and a heuristic ant colony algorithm, a tabu search algorithm and a genetic algorithm are designed, so that the packet loss rate, the link congestion and the call loss rate of a multilayer satellite network are reduced. Based on dynamic flow perception, the LEO satellite is helped to select a proper MEO satellite for access by analyzing the length of a flow queue and the size of flow on an interlayer link, and the congestion of the flow on an MEO layer is avoided. Modeling satellite time evolution as cyclic hopping between finite state machines (FSA), and maximizing the number of calls carried by the network by adopting a two-stage heuristic algorithm of optimizing the topological state first and then optimizing the flow distribution.
The other type of scheme for optimizing the interlayer link allocation aims to improve the topological stability of the interlayer link and reduce the switching cost and the system complexity. Three inter-layer link selection schemes exist, namely shortest distance link establishment, longest connection time link establishment and maximum resource utilization link establishment. At present, the longest connection time is widely favored by virtue of longer service time, namely, each low-orbit satellite selects a high-orbit satellite which can predict the longest connection time to build a link. However, link switching in isolation of each low-earth satellite makes the topological time slot more fragmented, the number of topologies increases, and the topological characterization and routing calculation become more complicated. Based on the problem, an optimization algorithm for merging topology time slots is provided, and the duration of the topology is prolonged. The prior art provides a centralized decision-making interlayer link allocation strategy, so that all links are switched at a specified time, and the topology dynamics is reduced. But this also causes the MEO and LEO satellites to isolate from each other at the time of link reconstruction, losing connectivity. Therefore, a two-stage synchronous switching strategy for the interlayer laser link is provided, the interlayer link is divided into two groups for alternate switching, the network connectivity is ensured, the topology dynamic property is reduced, and the constellation switching overhead is reduced.
The method provides an interlayer topology design scheme for enhancing information transmission capability and improving topology stability, but the constraints of the two network performances on the topology design are relatively isolated, so that the interlayer link configuration scheme can only be selected between the improvement of information carrying capability and the topology stability. And the configuration of the number of the satellite antennas of the low-orbit and high-orbit decision schemes is relatively single, so that the influence dimensionality of antenna parameters on the interlayer topological performance is difficult to expand. Therefore, a new method for designing an interlayer link topology facing a leomoeo double-layer satellite constellation is urgently needed to solve the problem that the prior art cannot simultaneously improve the interlayer information carrying capacity and the topology stability.
Through the above analysis, the problems and defects of the prior art are as follows:
(1) The constraint of the network performance of the existing interlayer topology design scheme on the topology design is relatively isolated, so that the interlayer link configuration scheme can only be selected from the two schemes of improving the information bearing capacity and the topology stability, and the interlayer information bearing capacity and the topology stability cannot be improved at the same time.
(2) The configuration of the number of satellite antennas of the low-orbit and high-orbit decision schemes of the existing interlayer topology design scheme is relatively single, and the influence dimensionality of antenna parameters on the interlayer topology performance is difficult to expand.
The difficulty in solving the above problems and defects is: the double-layer satellite networking mode invisibly enlarges the network scale, increases the types and the number of inter-satellite links, improves the difficulty of inter-layer inter-satellite link design, simultaneously, the satellite-borne antenna parameters are important factors influencing the inter-layer bearing capacity, and how to simultaneously improve the inter-layer information bearing capacity and the topological stability becomes a difficult point of the inter-layer inter-satellite link design.
The significance of solving the problems and the defects is as follows: meanwhile, the inter-satellite link connection method for improving the interlayer information capability and the topological stability of the double-layer satellite networking can ensure the reliability and the network communication performance of the inter-satellite link, effectively analyze the influence dimensionality of antenna parameters on the interlayer topological performance, and provide reference for the design of a satellite-borne antenna.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides an interlayer link topology design method for LEOMEO double-layer satellite constellation, aiming at solving the problem that the prior art cannot simultaneously improve the interlayer information bearing capacity and the topology stability.
The invention is realized in such a way, and provides a LEOMEO double-layer satellite constellation-oriented interlayer link topology design method, which comprises the following steps:
constructing a double-layer satellite network system and establishing a performance evaluation index; based on a virtual topological scheme, a topological structure of each time slot is modeled by adopting time slicing, a 0-1 integer linear programming scheme based on time evolution is designed, and a topological sequence of an interlayer link is designed under the constraints of a visible relation, antenna transmitting power and the number of interlayer antennas.
Further, the LEOMEO double-layer satellite constellation-oriented interlayer link topology design method comprises the following steps:
constructing a double-layer satellite network system comprising an LEO constellation and an MEO constellation;
step two, establishing a performance evaluation index for evaluating the bearing capacity of the interlayer information and the stability of the interlayer link according to the double-layer satellite network system comprising the LEO constellation and the MEO constellation in the step one, wherein the performance evaluation is used as an optimization target parameter of the model;
step three, designing an interlayer link topological sequence according to the double-layer satellite network system comprising the LEO constellation and the MEO constellation in the step one, wherein the interlayer link topological sequence needs to meet the constraint of system parameters, and establishing a constraint model based on the visibility of an interlayer satellite, the transmitting power of a satellite antenna, the number of LEO satellite antennas and the number of MEO satellite antennas;
step four, optimizing the evaluation index in the step two under the constraint of the constraint condition in the step three according to the double-layer satellite network system comprising the LEO constellation and the MEO constellation in the step one to obtain a single-target 0-1 integer linear programming problem P1;
and step five, designing a time evolution-based 0-1 integer linear programming algorithm to solve the design scheme Topo of the optimal interlayer link topology sequence in the step one, and obtaining the design scheme Topo of the interlayer link topology sequence which can simultaneously improve the interlayer information bearing capacity and the stability of the interlayer links under the condition of system parameter constraints such as satellite antenna parameters and the like.
Further, the constructing a two-layer satellite network system including the LEO constellation and the MEO constellation in the first step includes:
the number of LEO constellation satellites is SL, the orbit height is h L (ii) a The number of satellites of the MEO constellation is SM, and the orbit height is h M LEO and MEO can be formed by any Walker, polar orbit and other constellations, and each LEO satellite has A L An inter-layer link antenna, each MEO satellite has A M Inter-layer link antennaLines, each link requiring one LEO satellite antenna and one MEO satellite antenna for formation, the network planning period being 0, t]The planning period is equally divided into N time slots L (k) = [ (k-1) tau, k tau), k =1,2, \8230; N, the connection relation of MEO and LEO can be regarded as static topology in each time slot, the interlayer link between LEO and MEO constellation is expressed as:
wherein l (i,j,k) Showing the connection relation between the ith LEO satellite and the jth MEO satellite in the kth time slot, wherein 1 shows connection, 0 shows disconnection, and the design scheme Topo of the interlayer link topology sequence is shown as follows:
further, in the second step, according to the double-layer satellite network system including the LEO constellation and the MEO constellation in the first step, establishing a performance evaluation index for evaluating the inter-layer information carrying capacity and the stability of the inter-layer link includes:
for arbitrary inter-layer link topology sequences Topo (SL×SM×N) The inter-layer total link rate represents the sum of the rates of all links in each time slot, and the inter-layer information carrying capacity of the link design scheme is measured by the inter-layer total link rate, and the formula is as follows:
wherein r is (i,j,k) Indicating the ith LEO satellite and the jth MEO satellite in the kth time slot link l (i,j,k) The bit rate of (a).
The power consumption of a constellation is increased due to frequent switching of the interlayer links, the stability of the interlayer links is measured by the switching proportion of the interlayer links, and the proportion of the links switched between two topologies is defined as the Jacobian distance of the two topologiesFrom, the set of inter-layer links L (k) for any two slots 1 ) And L (k) 2 ) The Jacard distance for both topologies is defined as:
wherein, | L (k) 1 )∩L(k 2 )|/|L(k 1 )∪L(k 2 ) I represents the vicard similarity coefficient of the two topologies, i.e., the ratio of the number of links without handover to the total number of links.
Further, in the third step, according to the two-layer satellite network system including the LEO constellation and the MEO constellation in the first step, the design of the inter-layer link topology sequence needs to meet the constraint of the system parameters, and the establishment of the constraint model based on the visibility of the inter-layer satellite, the satellite antenna transmission power, the number of LEO satellite antennas, and the number of MEO satellite antennas includes:
(1) Visibility constraints of inter-layer satellites: calculating whether the two satellites in any time slot satisfy the visual range visible relationship to obtain a visible relationship topological sequence:
if s (i,j,k) =1, indicating that the ith LEO satellite and the jth MEO satellite are in line of sight in the kth time slot; if s (i,j,k) And =0, indicating that the line of Sight is invisible and an inter-layer link cannot be established, so the visibility constraint of the visible relation sequence Sight to the inter-layer link topology sequence Topo is expressed as:
s (i,j,k) -l (i,j,k) ≥0。
(2) Antenna transmission power constraint: the wireless channel transmits data subject to path fading and transceiver antenna parameters. SNR of one interlayer link in any time slot (i,j,k) Expressed as:
wherein, pt (i,j,k) Is a link l (i,j,k) Transmit power of G t And G r Transmission and reception gain, k, respectively, of a satellite antenna B Is the Boltzmann constant, T s Is the system noise temperature, r (i,j,k) Is a link l (i,j,k) Data bit rate of (Lp) (i,j,k) The free space path loss for the link in k slots is expressed as:
wherein f is transmission frequency, c is electromagnetic wave propagation velocity, d (i,j,k) For the maximum value of the visual distance between the ith LEO satellite and the jth MEO satellite in the kth time slot, according to the Shannon formula, an interlayer link l (i,j,k) The actual bit rate will not exceed the maximum bit rate calculated by the shannon equation, resulting in the following inequality:
r (i,j,k) ≤Blog 2 (1+SNR (i,j,k) )；
wherein, B is the bandwidth, obtains the value range of the transmitting power through the transformation:
to achieve a bit rate r (i,j,k) Inter-layer link l (i,j,k) The minimum transmit power of (c) is:
based on the consideration of the overall power consumption of the satellite, the link rate is maintained at r (i,j,k) On the basis that the transmission power of any satellite cannot exceed the nominal threshold Tx th I.e. the transmit power constraint of the satellite antenna is:
calculating the transmission power of each link on the basis of the visible relation topology sequence Topo, and calculating the s of the links which do not meet the constraint (i,j,k) And setting zero.
(3) Interlayer link antenna number constraint: each interlayer link needs to be maintained by an LEO satellite antenna and an MEO satellite antenna, the satellite antenna only aims at one satellite in any time slot, whether the satellite is switched or not is considered only before the beginning of the next time slot, and the maximum number of links which can be respectively established by each LEO satellite and the MEO satellite in the same time slot is determined and is respectively A L And A M In the kth time slot, the constraint of the number of satellite antennas on the topological sequence of the interlayer links is as follows:
(4) Adjacent time slot constraint: taking the solution of the time slot interlayer link topology design as the constraint condition for solving the next time slot, and expressing the solution as follows:
l (i,j,k) s (i,j,k+1) -l (i,j,k+1) ≤0,k＝1,2,…,N-1；
according to the topological design scheme of the time slot, the links which still meet the visible relation in the next time slot are still kept in the time slot solving process, only the interlayer links which need to be switched are optimized, the Jacard distance between the solution of the next time slot and the solution of the time slot is shortened, and the link switching proportion of the whole topological sequence is reduced.
Further, in the fourth step, according to the two-layer satellite network system including the LEO constellation and the MEO constellation in the first step, under the constraint of the constraint condition in the third step, optimizing the evaluation index in the second step to obtain a single-objective 0-1 integer linear programming problem P1 includes:
wherein l (i,j,k) Is a Boolean variable, r (i,j,k) ,s (i,j,k) ,d (i,j,k) ,A L ,A M SL, SM, N are known quantities.
Further, the step five of designing a time evolution-based 0-1 integer linear programming algorithm to solve the design scheme Topo of the optimal inter-layer link topology sequence in the step one includes:
according to the constraint conditions of the constellation and the antenna parameters, except the constraint of the optimal topology of the previous time slot, the optimal inter-layer topology in the first time slot is calculated by utilizing the existing 0-1 integer linear programming toolbox with the aim of maximizing the total link rate between layers, and the next time slot topology constraint T is initialized by multiplying the visible relation point of the optimal topology and the next time slot pre (ii) a For each subsequent time slot, according to the 0-1 integer linear programming problem P1 and the topological constraint T of the single target in the step four pre Calculating a topological optimization result under the time slot by using 0-1 integer linear programming, and updating constraint conditions of topological solution of the next time slot in the same mode until topological solution of all time slots is finished; and evaluating the total inter-layer link rate C and the link switching ratio STA of the inter-layer link topology sequence Topo according to the performance evaluation index in the step two.
Another object of the present invention is to provide a system for designing an interlayer link topology for a LEOMEO double-layer satellite constellation, which implements the method for designing an interlayer link topology for a LEOMEO double-layer satellite constellation, the system for designing an interlayer link topology for a LEOMEO double-layer satellite constellation including:
the double-layer satellite network system construction module is used for constructing a double-layer satellite network system comprising an LEO constellation and an MEO constellation;
the performance evaluation index establishing module is used for establishing a performance evaluation index for evaluating the bearing capacity of the interlayer information and the stability of the interlayer link according to the double-layer satellite network system;
the constraint model establishing module is used for designing a topological sequence of an interlayer link according to the double-layer satellite network system to meet the constraint of system parameters, and establishing a constraint model based on the visibility of an interlayer satellite, the transmitting power of a satellite antenna, the number of LEO satellite antennas and the number of MEO satellite antennas;
the evaluation index optimization module is used for optimizing the evaluation index under the constraint of the constraint condition according to the double-layer satellite network system to obtain a single-target 0-1 integer linear programming problem P1;
and the design scheme solving module is used for designing a time evolution-based 0-1 integer linear programming algorithm to solve the design scheme Topo of the optimal interlayer link topology sequence.
It is a further object of the invention to provide a computer device comprising a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to perform the steps of:
constructing a double-layer satellite network system and establishing a performance evaluation index; based on a virtual topological scheme, a topological structure of each time slot is modeled by adopting time slicing, a 0-1 integer linear programming scheme based on time evolution is designed, and a topological sequence of an interlayer link is designed under the constraints of a visible relation, antenna transmitting power and the number of interlayer antennas.
It is another object of the present invention to provide a computer-readable storage medium storing a computer program which, when executed by a processor, causes the processor to perform the steps of:
constructing a double-layer satellite network system and establishing a performance evaluation index; based on a virtual topological scheme, a topological structure of each time slot is modeled by adopting time slicing, a 0-1 integer linear programming scheme based on time evolution is designed, and a topological sequence of an interlayer link is designed under the constraints of a visible relation, antenna transmitting power and the number of interlayer antennas.
Another objective of the present invention is to provide an information data processing terminal, where the information data processing terminal is configured to implement the LEOMEO-oriented double-layer satellite constellation interlayer link topology design system.
By combining all the technical schemes, the invention has the advantages and positive effects that: according to the LEOMEO double-layer satellite constellation-oriented interlayer link topology design method, by designing an evaluation model of the interlayer information carrying capacity and the topology stability of the multilayer constellation, the interlayer total link rate is maximized based on the time evolution of the interlayer topology, the topology performance under the flexible configuration of antenna parameters is explored, the interlayer information carrying capacity is improved, the topology stability is guaranteed, and the network topology maintenance cost is reduced.
The invention is based on a virtual topology scheme, adopts time slicing to model a topology structure of each time slot, designs a 0-1 integer linear programming scheme based on time evolution, designs a topology sequence of an interlayer link under the constraints of a visible relation, antenna transmitting power and the number of interlayer antennas, can optimize the connection relation between a low-orbit satellite and a high-orbit satellite, improves the interlayer topology stability and the interlayer information bearing capacity, enhances the stability of the interlayer link, and reduces the switching frequency of the interlayer satellite antenna.
According to simulation experiments, compared with the shortest distance link establishment algorithm, the time evolution-based 0-1 integer linear programming algorithm has higher interlayer information bearing capacity and higher topological stability.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a flowchart of an interlayer link topology design method for a leomoeo double-layer satellite constellation according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of an interlayer link topology design method for a leomoeo two-layer satellite constellation according to an embodiment of the present invention.
Fig. 3 is a structural block diagram of an interlayer link topology design system for a leomoeo double-layer satellite constellation according to an embodiment of the present invention;
in the figure: 1. a double-layer satellite network system construction module; 2. a performance evaluation index establishing module; 3. a constraint model building module; 4. an evaluation index optimization module; 5. and designing a scheme solving module.
Fig. 4 is a diagram of a two-tier satellite network system according to an embodiment of the present invention.
Fig. 5 is a Venn diagram of various inter-layer link building schemes provided by embodiments of the present invention.
Fig. 6 is a schematic diagram illustrating a comparison of total link rates of a time evolution algorithm and a shortest distance link establishment according to an embodiment of the present invention.
Fig. 7 is a schematic diagram illustrating a comparison of a link switching ratio between a time evolution algorithm and a shortest distance link establishment according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Aiming at the problems in the prior art, the invention provides a method for designing an interlayer link topology for a LEOMEO double-layer satellite constellation, and the invention is described in detail below with reference to the accompanying drawings.
As shown in fig. 1, the method for designing an interlayer link topology for a leomoeo two-layer satellite constellation according to an embodiment of the present invention includes the following steps:
s101, constructing a double-layer satellite network system comprising an LEO constellation and an MEO constellation;
s102, establishing a performance evaluation index for evaluating the bearing capacity of the interlayer information and the stability of the interlayer link according to the double-layer satellite network system comprising the LEO constellation and the MEO constellation of S101;
s103, according to the double-layer satellite network system comprising the LEO constellation and the MEO constellation of S101, designing an interlayer link topological sequence to meet the constraint of system parameters, and establishing a constraint model based on the visibility of an interlayer satellite, the transmitting power of a satellite antenna, the number of LEO satellite antennas and the number of MEO satellite antennas;
s104, optimizing the evaluation index of S102 under the constraint of the constraint condition of S103 according to the double-layer satellite network system comprising the LEO constellation and the MEO constellation of S101 to obtain a single-target 0-1 integer linear programming problem P1;
and S105, designing a design scheme Topo of the optimal interlayer link topology sequence for solving the S101 based on a time evolution-based 0-1 integer linear programming algorithm.
A schematic diagram of the method for designing an interlayer link topology for a leomoeo double-layer satellite constellation according to the embodiment of the present invention is shown in fig. 2.
As shown in fig. 3, the system for designing an interlayer link topology for a leomoeo two-layer satellite constellation according to an embodiment of the present invention includes:
the double-layer satellite network system construction module 1 is used for constructing a double-layer satellite network system comprising an LEO constellation and an MEO constellation;
the performance evaluation index establishing module 2 is used for establishing a performance evaluation index for evaluating the bearing capacity of the interlayer information and the stability of the interlayer link according to the double-layer satellite network system;
the constraint model establishing module 3 is used for designing a topological sequence of an interlayer link according to the double-layer satellite network system to meet the constraint of system parameters, and establishing a constraint model based on the visibility of an interlayer satellite, the transmitting power of a satellite antenna, the number of LEO satellite antennas and the number of MEO satellite antennas;
the evaluation index optimization module 4 is used for optimizing the evaluation index according to the double-layer satellite network system under the constraint of the constraint condition to obtain a single-target 0-1 integer linear programming problem P1;
and the design scheme solving module 5 is used for designing a time evolution-based 0-1 integer linear programming algorithm to solve the design scheme Topo of the optimal inter-layer link topology sequence.
The technical solution of the present invention is further described below with reference to specific examples.
Aiming at the defects of the prior art, the invention provides an LEO/MEO double-layer satellite constellation-oriented interlayer link topology design method, which is based on a virtual topology scheme, adopts time slices to model the topology structure of each time slot, designs a 0-1 integer linear programming scheme based on time evolution, and designs a topology sequence of an interlayer link under the constraints of a visible relation, antenna transmitting power and the number of interlayer antennas.
In order to achieve the purpose, the technical scheme of the invention comprises the following steps:
(1) Consider a two-tier satellite network system (see fig. 4) comprising a LEO constellation and a MEO constellation, where the number of LEO constellation satellites is SL and the orbital altitude is h L (ii) a The number of satellites of the MEO constellation is SM, and the orbit height is h M LEO and MEO can be formed by any Walker, polar orbit and other constellations, and each LEO satellite has A L An inter-layer link antenna, each MEO satellite has A M Each interlayer link antenna needs one LEO satellite antenna and one MEO satellite antenna for forming each link, and the planning period of the network is [0,T]The planning period is equally divided into N time slots L (k) = [ (k-1) tau, k tau) by a time interval tau, k =1,2, \8230, N, the connection relation of MEO and LEO can be regarded as static topology in each time slot, at any time t > 0, and the interlayer link between LEO and MEO constellation can be expressed as:
wherein l (i,j,k) Showing the connection relationship between the ith LEO satellite and the jth MEO satellite in the kth time slot, where 1 shows connection, 0 shows no connection, and the design scheme Topo of the inter-layer link topology sequence can be expressed as:
Topo＝{L(1),L(2),…,L(k),…,L(N)},
i＝1,2,…,SL,j＝1,2,…,SM,k＝1,2,…,N
(2) According to the double-layer satellite network system comprising the LEO constellation and the MEO constellation in the step (1), establishing a performance evaluation index for evaluating the bearing capacity of the interlayer information and the stability of the interlayer link:
for any oneInter-layer link topology sequence Topo (SL×SM×N) The inter-layer total link rate represents the sum of the rates of all links in each time slot, and the inter-layer information carrying capacity of the link design scheme is measured by the inter-layer total link rate, and the formula is as follows:
wherein r is (i,j,k) Indicating that the ith LEO satellite and the jth MEO satellite are in the kth time slot link l (i,j,k) The bit rate of (c).
The frequent switching of the interlayer links can increase the power consumption of constellations, the stability of the interlayer links is measured by the switching proportion of the interlayer links, the ratio of the links switched between two topologies is defined as the Jacard distance of the two, and an interlayer link set L (k) of any two time slots 1 ) And L (k) 2 ) The Jacard distance for both topologies is defined as:
wherein | L (k) 1 )∩L(k 2 )|/|L(k 1 )∪L(k 2 ) I represents the vicard similarity coefficient of the two topologies, i.e., the ratio of the number of links without handover to the total number of links.
(3) According to the double-layer satellite network system comprising the LEO constellation and the MEO constellation in the step (1), the design of an interlayer link topological sequence needs to meet the constraint of system parameters, and a constraint model is established by considering the visibility of an interlayer satellite, the transmitting power of a satellite antenna, the number of LEO satellite antennas and the number of MEO satellite antennas:
(3a) Visibility constraints of inter-layer satellites: calculating whether the two satellites in any time slot meet the visual range visible relationship or not to obtain a visible relationship topological sequence:
Sight＝{S(1),S(2),…,S(k),…,S(N)}
i＝1,2,…,SL,j＝1,2,…,SM,k＝1,2,…,N
if s (i,j,k) =1, indicating that the i LEO satellite and the j MEO satellite are in sight distance visibility in the k time slot if s (i,j,k) And =0, indicating that the line of Sight is invisible and an inter-layer link cannot be established, so the visibility constraint of the visible relation sequence Sight to the inter-layer link topology sequence Topo is expressed as:
s (i,j,k) -l (i,j,k) ≥0
(3b) Antenna transmission power constraint: the wireless channel transmits data subject to path fading and transceiver antenna parameters. SNR of one interlayer link in any time slot (i,j,k) Can be expressed as:
wherein Pt (i,j,k) Is a link l (i,j,k) Transmit power of G t And G r Transmission and reception gain, k, respectively, of a satellite antenna B Is Boltzmann constant, T s Is the system noise temperature, r (i,j,k) Is a link l (i,j,k) Data bit rate of (Lp) (i,j,k) The free space path loss in k slots for this link can be expressed as:
where f is the transmission frequency, c is the propagation velocity of the electromagnetic wave, d (i,j,k) For the maximum value of the visual distance between the ith LEO satellite and the jth MEO satellite in the kth time slot, according to the Shannon formula, an interlayer link l (i,j,k) The actual bit rate will not exceed the maximum bit rate calculated by the shannon formula, resulting in the inequality as follows:
r (i,j,k) ≤Blog 2 (1+SNR (i,j,k) )
wherein, B is the frequency bandwidth, and the value range of the transmitting power can be obtained through conversion:
therefore, to achieve the bit rate r (i,j,k) Inter-layer link l (i,j,k) The minimum transmit power of (c) is:
based on the consideration of the overall power consumption of the satellite, the link rate is maintained to be r (i,j,k) On the basis that the transmission power of any satellite cannot exceed the rated threshold Tx th I.e. the transmit power constraint of the satellite antenna is:
calculating the transmission power of each link on the basis of the visible relation topology sequence Topo, and calculating the s of the links which do not satisfy the constraint of the formula (i,j,k) And setting zero.
(3c) Interlayer link antenna number constraint: each interlayer link needs to be maintained by one LEO satellite antenna and one MEO satellite antenna, in any time slot, the satellite antenna is only aligned with one satellite, whether the satellite is switched or not is considered only before the beginning of the next time slot, and in the same time slot, the maximum number of links which can be respectively established by each LEO satellite and MEO satellite is determined and is respectively A L And A M In the kth time slot, the constraint of the number of satellite antennas on the topological sequence of the interlayer links is as follows:
(3d) Adjacent time slot constraint: taking the solution of the time slot interlayer link topology design as the constraint condition for solving the next time slot, can be expressed as:
l (i,j,k) s (i,j,k+1) -l (i,j,k+1) ≤0,k＝1,2,…,N-1
the specific meanings are as follows: according to the topological design scheme of the time slot, the link which still meets the visible relation in the next time slot is still kept in the time slot solving process, only the interlayer link which needs to be switched is optimized, and the Jacard distance between the solution of the next time slot and the solution of the time slot can be reduced by the strategy, so that the link switching proportion of the whole topological sequence is reduced.
(4) According to the double-layer satellite network system comprising the LEO constellation and the MEO constellation in the step (1), under the constraint of the constraint condition in the step (3), optimizing the evaluation index in the step (2) to obtain a single-target 0-1 integer linear programming problem P1:
P1:
s.t.
s (i,j,k) -l (i,j,k) ≥0,
l (i,j,k) s (i,j,k+1) -l (i,j,k+1) ≤0,1≤k≤N-1,
wherein l (i,j,k) Is a Boolean variable, r (i,j,k) ,s (i,j,k) ,d (i,j,k) ,A L ,A M SL, SM, N are known quantities.
(5) Designing a design scheme Topo of the optimal inter-layer link topology sequence in the step (1) based on a time evolution 0-1 integer linear programming algorithm:
firstly, according to constellation and antenna parameter constraint conditions (except the constraint of the optimal topology of the previous time slot), with the aim of maximizing the total link rate between layers, the optimal topology between layers in the first time slot is calculated by utilizing the existing 0-1 integer linear programming tool box, and the topology constraint T of the next time slot is initialized by multiplying the visible relation point of the optimal topology and the next time slot pre Then, for each subsequent time slot, according to the single target 0-1 integer linear programming problem P1 and the topological constraint T in the step (4) pre And (3) calculating a topology optimization result under the time slot by using 0-1 integer linear programming, updating constraint conditions of topology solution of the next time slot in the same mode until topology solution of all time slots is finished, and finally evaluating the total inter-layer link rate C and the link switching ratio STA of the inter-layer link topology sequence Topo according to the performance evaluation index in the formula step (2).
The invention provides an evaluation model of information bearing capacity and topological stability among multiple layers of constellation layers, maximizes the total link rate among the layers based on the time evolution of the inter-layer topology, explores the topological performance under the flexible configuration of antenna parameters, improves the information bearing capacity among the layers, ensures the topological stability and reduces the maintenance cost of network topology.
The technical effects of the present invention will be described in detail with reference to simulation experiments.
The software platform of the simulation experiment of the invention is as follows: the Windows 7 operating system, MATLAB R2018b, simulation scenario are based on a LEO/MEO double-layer satellite constellation, wherein the LEO constellation refers to the constellation with 1584 satellites in Starlink, and specific parameters are shown in Table 1. The transmission gain of the interlayer link antenna is 20dB, the receiving gain is 44.8dB, the frequency bandwidth is 100MHz, the central frequency point is 20GHz, the bit rate of all links is 1Gbps, and the transmission power threshold value is 19.03dBW.
TABLE 1 LEO/MEO double-layer satellite constellation parameters
And calculating a visible relation matrix and a link distance matrix of the LEO satellite and the MEO in each time slot. The simulation run time was 24 hours, 60s for slot length, totaling 1440 slots. Based on the constellation parameter constraint, the inter-layer total link rate and the link switching proportion of two algorithm topology design schemes are tested, and respectively:
algorithm 1: time evolution based 0-1 integer linear programming scheme: and considering the constraint of the last time slot topology optimization result on the time slot optimization process.
And 2, algorithm: the link establishment scheme between layers based on the shortest distance is as follows: and under the constraint of meeting the visibility relation, the number of satellite antennas and the transmitting power, the LEO satellite in each time slot selects the MEO satellite closest to the time slot to build a link.
Step one, a double-layer satellite network system comprising an LEO constellation and an MEO constellation is considered, wherein the number of LEO constellation satellites is SL, and the orbital height is h L (ii) a The number of satellites of the MEO constellation is SM, and the orbit height is h M LEO and MEO can be formed by any Walker, polar orbit and other constellations, and each LEO satellite has A L An inter-layer link antenna, each MEO satellite has A M The formation of each link requires one LEO satellite antenna and one MEO satellite antenna, and the planning period of the network is [0,T]The planning period is equally divided into N time slots L (k) = [ (k-1) tau, k tau), k =1,2, \8230; N, in each time slot, the connection relation of MEO and LEO can be regarded as static topology, and at any time t > 0, the interlayer link between LEO and MEO constellation can be expressed as:
wherein l (i,j,k) The connection relationship between the ith LEO satellite and the jth MEO satellite in the kth time slot is represented, 1 represents connection, 0 represents disconnection, and the design scheme Topo of the inter-layer link topology sequence can be represented as:
Topo＝{L(1),L(2),…,L(k),…,L(N)},
i＝1,2,…,SL,j＝1,2,…,SM,k＝1,2,…,N
by optimizing the topological sequence Topo of the link between layers, the optimal transmission capability between layers and the stability of the topological sequence are realized under the constraints of the antenna transmission power requirement, the number of antennas between layers and the visible relationship of a satellite.
Step two, establishing a performance evaluation index for evaluating the bearing capacity of the interlayer information and the stability of the interlayer link according to the double-layer satellite network system comprising the LEO constellation and the MEO constellation in the step one:
for arbitrary inter-layer link topology sequences Topo (SL×SM×N) The inter-layer total link rate represents the sum of the rates of all links in each time slot, and the inter-layer information carrying capacity of the link design scheme is measured by the inter-layer total link rate, and the formula is as follows:
wherein r is (i,j,k) Indicating that the ith LEO satellite and the jth MEO satellite are in the kth time slot link l (i,j,k) The bit rate of (c).
The frequent switching of the interlayer links can increase the power consumption of constellations, the stability of the interlayer links is measured by the switching proportion of the interlayer links, the proportion of the links switched between two topologies is defined as the Jacard distance of the two, and an interlayer link set L (k) of any two time slots 1 ) And L (k) 2 ) The Jacard distance for both topologies is defined as:
wherein | L (k) 1 )∩L(k 2 )|/|L(k 1 )∪L(k 2 ) I represents twoThe vicard similarity factor of the topology, i.e., the fraction of the number of links for which no handover has occurred, in the total number of links.
Step three, according to the double-layer satellite network system comprising the LEO constellation and the MEO constellation, the design of the topological sequence of the interlayer link needs to meet the constraint of system parameters, and a constraint model is established by considering the visibility of the interlayer satellite, the transmitting power of the satellite antenna, the number of the LEO satellite antennas and the number of the MEO satellite antennas:
(3a) Visibility constraints of inter-layer satellites: calculating whether the two satellites in any time slot satisfy the visual range visible relationship to obtain a visible relationship topological sequence:
Sight＝{S(1),S(2),…,S(k),…,S(N)}
i＝1,2,…,SL,j＝1,2,…,SM,k＝1,2,…,N
if s (i,j,k) =1, indicating that the i LEO satellite and the j MEO satellite are in sight distance visibility in the k time slot if s (i,j,k) =0, indicating that the line of Sight is not visible and the inter-layer link cannot be established, the visibility constraint of the visible relation sequence Sight on the inter-layer link topology sequence Topo is expressed as:
s (i,j,k) -l (i,j,k) ≥0
(3b) Antenna transmission power constraint: the wireless channel transmits data subject to path fading and transceiver antenna parameters. SNR of one interlayer link in any time slot (i,j,k) Can be expressed as:
wherein Pt (i,j,k) Is a link l (i,j,k) Transmit power of G t And G r Transmission and reception gain, k, respectively, of a satellite antenna B Is Boltzmann constant, T s Is the system noise temperature, r (i,j,k) Is a link l (i,j,k) Data bit rate of (Lp) (i,j,k) The free space path loss in k slots for this link can be expressed as:
where f is the transmission frequency, c is the propagation velocity of the electromagnetic wave, d (i,j,k) For the maximum value of the visual distance between the ith LEO satellite and the jth MEO satellite in the kth time slot, according to the Shannon formula, an interlayer link l (i,j,k) The actual bit rate will not exceed the maximum bit rate calculated by the shannon formula, resulting in the inequality as follows:
r (i,j,k) ≤Blog 2 (1+SNR (i,j,k) )
wherein, B is the frequency bandwidth, and the value range of the transmitting power can be obtained through conversion:
therefore, to achieve the bit rate r (i,j,k) Inter-layer link l (i,j,k) The minimum transmit power of (c) is:
based on the consideration of the overall power consumption of the satellite, the link rate is maintained to be r (i,j,k) On the basis that the transmission power of any satellite cannot exceed the nominal threshold Tx th I.e. the transmit power constraint of the satellite antenna is:
calculating the transmission power of each link on the basis of the visible relation topological sequence Topo, and calculating the s of the links which do not satisfy the constraint of the formula (i,j,k) And setting zero.
(3c) Between layersThe number of link antennas constraint: each interlayer link needs to be maintained by one LEO satellite antenna and one MEO satellite antenna, in any time slot, the satellite antenna is only aligned with one satellite, whether the satellite is switched or not is considered only before the beginning of the next time slot, and in the same time slot, the maximum number of links which can be respectively established by each LEO satellite and MEO satellite is determined and is respectively A L And A M In the kth time slot, the constraint of the satellite antenna number on the interlayer link topology sequence is as follows:
(3d) Adjacent time slot constraint: taking the solution of the time slot interlayer link topology design as the constraint condition for solving the next time slot, can be expressed as:
l (i,j,k) s (i,j,k+1) -l (i,j,k+1) ≤0,k＝1,2,…,N-1
the specific meanings are as follows: according to the topological design scheme of the time slot, the links which still meet the visible relation in the next time slot are still kept in the time slot solving process, only the interlayer links which need to be switched are optimized, and the Jacard distance between the solution of the next time slot and the solution of the time slot can be reduced by the strategy, so that the link switching proportion of the whole topological sequence is reduced.
Step four, according to the double-layer satellite network system comprising the LEO constellation and the MEO constellation in the step one, optimizing the evaluation index in the step (2) under the constraint of the constraint condition in the step (3), and obtaining a single-target 0-1 integer linear programming problem P1:
P1:
s.t.
s (i,j,k) -l (i,j,k) ≥0,
l (i,j,k) s (i,j,k+1) -l (i,j,k+1) ≤0,1≤k≤N-1,
wherein l (i,j,k) Is a Boolean variable, r (i,j,k) ,s (i,j,k) ,d (i,j,k) ,A L ,A M SL, SM, N are known quantities.
Step five, designing a 0-1 integer linear programming algorithm based on time evolution to solve the design scheme Topo of the optimal interlayer link topology sequence in the step one:
firstly, according to constellation and antenna parameter constraint conditions (except the constraint of the optimal topology of the previous time slot), with the aim of maximizing the total link rate between layers, the optimal topology between layers in the first time slot is calculated by utilizing the existing 0-1 integer linear programming tool box, and the topology constraint T of the next time slot is initialized by multiplying the visible relation point of the optimal topology and the next time slot pre Then, for each subsequent time slot, according to the single target 0-1 integer linear programming problem P1 and the topological constraint T in the step (4) pre And (3) calculating a topology optimization result under the time slot by using 0-1 integer linear programming, updating constraint conditions of topology solution of the next time slot in the same mode until topology solution of all time slots is finished, and finally evaluating the total inter-layer link rate C and the link switching ratio STA of the inter-layer link topology sequence Topo according to the performance evaluation index in the formula step (2).
And (3) simulation results:
1. interlayer information carrying capacity evaluation:
fig. 5 depicts the results of a comparison of the time evolution based 0-1 integer linear programming scheme (algorithm 1) with the shortest distance link setup scheme (algorithm 2) in terms of the inter-layer total link rate. The total link rate of the two algorithms is increased along with the increase of the MEO satellite antenna number, and when the MEO satellite antenna number reaches a certain threshold value, the total link rate tends to be stable. The number of LEO antennas determines the upper limit of the overall link rate between layers, given the number of MEO antennas. This is because when there are fewer MEO antennas, there are limited LEO satellites to which each MEO satellite can connect, limiting the establishment of more inter-layer links. As the number of MEO antennas increases, the number of LEO antennas becomes a tight constraint, limiting the maximum number of links that can be formed between the two layers and determining the upper limit of the total link rate.
The inter-layer total link rate in algorithm 1 is not lower than algorithm 2 under any antenna configuration, and when the MEO antenna number is limited, the inter-layer total link rate in algorithm 1 is higher than algorithm 2. This is because algorithm 1 takes the maximum number of links between layers as the optimization target in each time slot, while algorithm 2 only selects the MEO satellite closest to itself to build the link. When multiple LEO satellites are closest to the same MEO satellite, if the MEO constructable number is saturated, the LEO satellites lose the opportunity to construct links, and algorithm 2 wastes antenna resources. However, the algorithm 1 can make a comprehensive decision according to the number of satellite antennas of the whole network and the visible relation, so that the situation is avoided.
2. Inter-layer topology stability assessment
Fig. 6 depicts the results of comparing the inter-layer link switching ratios of algorithm 1 and algorithm 2. Obviously, the link switching ratios of the two algorithms show different trend with the increase of the number of MEO antennas. Specifically, the link switching ratio of algorithm 2 gradually decreases as the number of MEO antennas increases, the topology stability increases, and the MEO antennas reach a stable value when sufficient. This is because the increase of MEO antennas improves the link establishment capability of MEOs for multiple LEO satellites, so that the increase of links with the shortest distance that can be maintained by adjacent time slots, the decrease of the jackard distance of adjacent topologies, and the reduction of link switching ratio. When the LEO satellite has more antennas, the link switching proportion of the topology obtained by the two algorithms is reduced, and the stability of the topology is improved. For algorithm 1, the number of links that the adjacent slot topology can maintain increases because the LEO antenna constraints become loose. For the algorithm 2, when each LEO satellite selects several MEO satellites that are closest to each other, the situation that all the satellites are far away in the next time slot is reduced, part of links can survive for a longer time, and the topology stability is improved.
As shown in fig. 7, the link switching proportion of algorithm 1 does not change significantly with the number of MEO antennas, and the overall value is lower than that of algorithm 2, so that the method has strong topological stability. This is because the topological design of each time slot of algorithm 1 refers to the topological design scheme of the previous time slot, and the links satisfying the constraints of the antennas and the visible relationship are maintained in the time slot, and only the links not satisfying the visible relationship are optimized. The link meeting the antenna number constraint in the last time slot is also satisfied in the time slot, so the MEO antenna number can only affect the topology design scheme of the first time slot, and cannot affect the topology optimization of the subsequent time slot. The number of links that can be maintained and switched in a subsequent time slot is only related to the visible relationship of that time slot and the optimization results of the upper time slot. Compared with the algorithm 2, the algorithm 1 greatly prolongs the survival time of the sustainable link, and is not influenced by the change of the link distance, so that the link switching proportion of the algorithm 1 is far lower than that of the algorithm 2.
In summary, compared with the shortest distance link establishment algorithm, the time evolution-based 0-1 integer linear programming algorithm has higher interlayer information carrying capacity and higher topological stability.
In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When used in whole or in part, is implemented in a computer program product that includes one or more computer instructions. When loaded or executed on a computer, cause the flow or functions according to embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, the computer instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, digital Subscriber Line (DSL), or wireless (e.g., infrared, wireless, microwave, etc.)). The computer readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that includes one or more available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid State Disk (SSD)), among others.
The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.
Claims (4)
1. An interlayer link topology design method for LEOMEO double-layer satellite constellation is characterized by comprising the following steps:
step one, constructing a double-layer satellite network system comprising an LEO constellation and an MEO constellation, comprising the following steps: the number of LEO constellation satellites is SL, the orbit height is h L (ii) a The number of satellites of the MEO constellation is SM, and the orbit height is h M LEO and MEO can be formed by any Walker, polar orbit constellation, each LEO satellite has A L An inter-layer link antenna, each MEO satellite has A M Each interlayer link antenna needs one LEO satellite antenna and one MEO satellite antenna for forming each link, and the planning period of the network is [0,T]The planning period is equally divided into N time slots L (k) = [ (k-1) tau, k tau), k =1,2, \8230; N, the connection relation of MEO and LEO can be regarded as static topology in each time slot, the interlayer link between LEO and MEO constellation is expressed as:
wherein l (i,j,k) Showing the connection relationship between the ith LEO satellite and the jth MEO satellite in the kth time slot, wherein 1 shows connection, 0 shows no connection, and the design scheme Topo of the interlayer link topology sequence is shown as follows:
Topo＝{L(1),L(2),…,L(k),…,L(N)},
i＝1,2,…,SL,j＝1,2,…,SM,k＝1,2,…,N
step two, establishing a performance evaluation index for evaluating the interlayer information bearing capacity and the stability of the interlayer link according to the double-layer satellite network system comprising the LEO constellation and the MEO constellation in the step one, wherein the performance evaluation index comprises the following steps: for arbitrary inter-layer link topology sequences Topo (SL×SM×N) The total link rate between layers represents the sum of the average rates of all links between layers in each time slot, the total link rate between layers is used for measuring the information bearing capacity between layers of a link design scheme, and the formula is as follows:
wherein r is (i,j,k) Indicating that the ith LEO satellite and the jth MEO satellite are in the kth time slot link l (i,j,k) The bit rate of (d);
the frequent switching of the interlayer links can increase the power consumption of constellations, the stability of the interlayer links is measured by the switching proportion of the interlayer links, the proportion of the links switched between two topologies is defined as the Jacard distance of the two, and an interlayer link set L (k) of any two time slots 1 ) And L (k) 2 ) The Jacobian distance for both topologies is defined as:
wherein, | L (k) 1 )∩L(k 2 )|/|L(k 1 )∪L(k 2 ) I represents the Jacard similarity coefficient of the two topologies, namely the proportion of the number of the links which are not switched in the total number of the links;
step three, according to the double-layer satellite network system comprising the LEO constellation and the MEO constellation in the step one, the design of the topological sequence of the interlayer link needs to meet the constraint of system parameters, and a constraint model is established based on the visibility of the interlayer satellite, the transmitting power of the satellite antenna, the number of LEO satellite antennas and the number of MEO satellite antennas, and comprises the following steps:
(1) Visibility constraints of inter-layer satellites: calculating whether the two satellites in any time slot meet the visual range visible relationship or not to obtain a visible relationship topological sequence:
Sight＝{S(1),S(2),…,S(k),…,S(N)}
i＝1,2,…,SL,j＝1,2,…,SM,k＝1,2,…,N
if s (i,j,k) =1, indicating that the ith LEO satellite and the jth MEO satellite are in line of sight in the kth time slot; if s (i,j,k) And =0, indicating that the line of Sight is invisible and an inter-layer link cannot be established, and the visibility constraint of the visible relation sequence Sight on the inter-layer link topology sequence Topo is expressed as follows:
s (i,j,k) -l (i,j,k) ≥0；
(2) Antenna transmission power constraint: the wireless channel transmission data is influenced by path attenuation and transceiver antenna parameters; SNR of one interlayer link in any time slot (i,j,k) Expressed as:
wherein, pt (i,j,k) Is a link l (i,j,k) Transmit power of G t And G r Transmission and reception gain, k, respectively, of a satellite antenna B Is Boltzmann constant, T s Is the system noise temperature, r (i,j,k) Is a link l (i,j,k) Data bit rate of (Lp) (i,j,k) The free space path loss for the link in k slots is expressed as:
wherein f is transmission frequency, c is electromagnetic wave propagation velocity, d (i,j,k) The maximum value of the sight distance between the ith LEO satellite and the jth MEO satellite in the kth time slot is the interlayer link l according to the Shannon formula (i,j,k) The actual bit rate will not exceed the maximum bit rate calculated by the shannon equation, resulting in the following inequality:
r (i,j,k) ≤Blog 2 (1+SNR (i,j,k) )；
wherein, B is the frequency bandwidth, obtains the value range of transmitting power through the transform:
to achieve a bit rate r (i,j,k) Interlayer link l (i,j,k) The minimum transmit power of (c) is:
based on the consideration of the overall power consumption of the satellite, the link rate is maintained to be r (i,j,k) On the basis that the transmission power of any satellite cannot exceed the rated threshold Tx th The transmit power constraint of the satellite antenna is:
calculating the transmission power of each link on the basis of the visible relation topology sequence Topo, and calculating the s of the links which do not meet the constraint (i,j,k) Setting to zero;
(3) Interlayer link antenna number constraint: each interlayer link needs to be maintained by an LEO satellite antenna and an MEO satellite antenna, the satellite antenna only aims at one satellite in any time slot, whether the satellite is switched or not is considered only before the beginning of the next time slot, and the maximum number of links which can be respectively established by each LEO satellite and the MEO satellite in the same time slot is determined and is respectively A L And A M In the kth time slot, the constraint of the satellite antenna number on the interlayer link topology sequence is as follows:
(4) Adjacent time slot constraint: taking the solution of the time slot interlayer link topology design as a constraint model for solving the next time slot, and expressing the solution as follows:
l (i,j,k) s (i,j,k+1) -l (i,j,k+1) ≤0,k＝1,2,…,N-1；
according to the topological design scheme of the time slot, the link which still meets the visible relation in the next time slot is still kept in the time slot solving process, only the interlayer link which needs to be switched is optimized, and the Jaccard distance between the solution of the next time slot and the solution of the time slot is reduced;
step four, according to the double-layer satellite network system comprising the LEO constellation and the MEO constellation in the step one, optimizing the evaluation index in the step two under the constraint of the constraint model in the step three to obtain a single-target 0-1 integer linear programming problem P1, which comprises the following steps:
wherein l (i,j,k) Is a Boolean variable, r (i,j,k) ,s (i,j,k) ,d (i,j,k) ,A L ,A M SL, SM, N are known quantities;
step five, designing a 0-1 integer linear programming algorithm based on time evolution to solve the design scheme Topo of the interlayer link topology sequence in the step one, wherein the design scheme Topo comprises the following steps: according to the constellation and antenna parameter constraint model, except the constraint of the optimal topology of the previous time slot, the maximum inter-layer total link rate is taken as the target, the inter-layer topology in the first time slot is calculated by utilizing the existing 0-1 integer linear programming tool box, and the next time slot topology constraint T is initialized by multiplying the visible relation point of the optimal topology and the next time slot pre (ii) a For each subsequent time slot, according to the 0-1 integer linear programming problem P1 and the topological constraint T of the single target in the step four pre Calculating a topological optimization result under the time slot by using 0-1 integer linear programming, and updating a constraint model for topological solution of the next time slot in the same manner until the topological solution of all time slots is finished; and evaluating the total inter-layer link rate C and the link switching ratio STA of the inter-layer link topology sequence Topo according to the performance evaluation index in the step two.
2. An LEOMEO two-layer satellite constellation-oriented interlayer link topology design system for implementing the LEOMEO two-layer satellite constellation-oriented interlayer link topology design method of claim 1, the LEOMEO two-layer satellite constellation-oriented interlayer link topology design system comprising:
the double-layer satellite network system construction module is used for constructing a double-layer satellite network system comprising an LEO constellation and an MEO constellation;
the performance evaluation index establishing module is used for establishing a performance evaluation index for evaluating the bearing capacity of the interlayer information and the stability of the interlayer link according to the double-layer satellite network system;
the constraint model establishing module is used for designing a topological sequence of an interlayer link according to the double-layer satellite network system to meet the constraint of system parameters, and establishing a constraint model based on the visibility of an interlayer satellite, the transmitting power of a satellite antenna, the number of LEO satellite antennas and the number of MEO satellite antennas;
the evaluation index optimization module is used for optimizing the evaluation index under the constraint of the constraint model according to the double-layer satellite network system to obtain a single-target 0-1 integer linear programming problem P1;
and the design scheme solving module is used for designing a time evolution-based 0-1 integer linear programming algorithm to solve the design scheme Topo of the interlayer link topology sequence.
3. A computer arrangement, characterized in that the computer arrangement comprises a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to carry out the steps of the LEOMEO bi-layer satellite constellation oriented interlayer link topology design method of claim 1.
4. An information data processing terminal, characterized in that it is adapted to implement the LEOMEO bi-level satellite constellation oriented interlayer link topology design system of claim 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111507541.XA CN114301794B (en) | 2021-12-10 | 2021-12-10 | LEOMEO double-layer satellite constellation-oriented interlayer link topology design method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111507541.XA CN114301794B (en) | 2021-12-10 | 2021-12-10 | LEOMEO double-layer satellite constellation-oriented interlayer link topology design method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114301794A CN114301794A (en) | 2022-04-08 |
| CN114301794B true CN114301794B (en) | 2023-02-24 |
Family
ID=80968230
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111507541.XA Active CN114301794B (en) | 2021-12-10 | 2021-12-10 | LEOMEO double-layer satellite constellation-oriented interlayer link topology design method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114301794B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115102605B (en) * | 2022-06-10 | 2023-10-17 | 北京交通大学 | Low-orbit satellite networking method combining equipartition and non-orthogonalization of coding domain |
| CN115276759B (en) * | 2022-06-21 | 2024-02-02 | 重庆邮电大学 | Double-layer satellite network connection plan design method based on weighted space-time diagram |
| CN117879696B (en) * | 2024-03-13 | 2024-05-14 | 北京大学 | Large-scale satellite constellation staged deployment method for low orbit satellite network |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106792959A (en) * | 2016-11-10 | 2017-05-31 | 上海交通大学 | Satellite interlayer topology reconstruction method based on discrete subtopology sequence and genetic algorithm |
| CN107370536A (en) * | 2017-07-19 | 2017-11-21 | 哈尔滨工业大学深圳研究生院 | Satellite network multi-broadcast routing method and system based on minimum connected dominating set |
| CN108540206A (en) * | 2018-04-11 | 2018-09-14 | 西安邮电大学 | A kind of three-layered satellite network load balancing method for routing based on volume forecasting |
| CN111953513A (en) * | 2020-07-02 | 2020-11-17 | 西安电子科技大学 | Constellation topology configuration characterization method and system for Walker constellation and application |
-
2021
- 2021-12-10 CN CN202111507541.XA patent/CN114301794B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106792959A (en) * | 2016-11-10 | 2017-05-31 | 上海交通大学 | Satellite interlayer topology reconstruction method based on discrete subtopology sequence and genetic algorithm |
| CN107370536A (en) * | 2017-07-19 | 2017-11-21 | 哈尔滨工业大学深圳研究生院 | Satellite network multi-broadcast routing method and system based on minimum connected dominating set |
| CN108540206A (en) * | 2018-04-11 | 2018-09-14 | 西安邮电大学 | A kind of three-layered satellite network load balancing method for routing based on volume forecasting |
| CN111953513A (en) * | 2020-07-02 | 2020-11-17 | 西安电子科技大学 | Constellation topology configuration characterization method and system for Walker constellation and application |
Non-Patent Citations (3)
| Title |
|---|
| 《VNF-Based Service Provision in Software Defined LEO Satellite Networks》;Ziye jia,Min Sheng,Di Zhou,Zhu Han;《IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS》;20210930;第20卷(第9期);全文 * |
| 基于不确定链路参数的卫星网络路由算法;周剑等;《系统工程与电子技术》;20190128(第05期);全文 * |
| 拓扑控制对Ad Hoc网络性能的影响;王炫等;《计算机科学》;20060625(第06期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114301794A (en) | 2022-04-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN114301794B (en) | LEOMEO double-layer satellite constellation-oriented interlayer link topology design method | |
| Saad et al. | Coalitional game theory for communication networks | |
| Sheng et al. | Energy efficiency and delay tradeoff in device-to-device communications underlaying cellular networks | |
| US9674073B2 (en) | Method and arrangement for route cost determination and selection with link cost interaction | |
| CN102355670B (en) | Multichannel wireless mesh network channel distribution method | |
| US7929460B2 (en) | Communication network topology determination | |
| CN107682135A (en) | A kind of network slice adaptive virtual resource allocation method based on NOMA | |
| CN105379412B (en) | A kind of system and method controlling multiple radio access nodes | |
| CN112953761B (en) | Virtual-real resource mapping method for virtual network construction in multi-hop network | |
| Oueis et al. | On the impact of backhaul network on distributed cloud computing | |
| CN109151864A (en) | A kind of migration decision and resource optimal distribution method towards mobile edge calculations super-intensive network | |
| CN114867030B (en) | Dual-time scale intelligent wireless access network slicing method | |
| CN112867088B (en) | Dynamic adjustment method and system for cloud-edge-end communication architecture | |
| CN114390630A (en) | Internet of things communication method, device and equipment based on information age and storage medium | |
| Cui et al. | A two-timescale resource allocation scheme in vehicular network slicing | |
| Yin et al. | Decentralized federated reinforcement learning for user-centric dynamic TFDD control | |
| Bushnaq et al. | Automatic network slicing for admission control, routing, and resource allocation in underwater acoustic communication systems | |
| CN117880852A (en) | Intelligent service migration method for edge Internet of vehicles system | |
| Majid Butt et al. | Relay selection schemes to minimise outage in wireless powered communication networks | |
| Feng et al. | Energy-efficient joint optimization of channel assignment, power allocation, and relay selection based on hypergraph for uplink mMTC networks | |
| US10182433B2 (en) | System and method for overlapping rate region zoning | |
| CN107846308A (en) | A kind of method and device for planning power telecom network ONU | |
| Bartsiokas et al. | A DL-enabled Relay Node Placement and Selection Framework in Multicellular Networks | |
| TWI607665B (en) | Method for assigning backhaul links in cooperative wireless network | |
| Zhuang et al. | When multi-access edge computing meets multi-area intelligent reflecting surface: A multi-agent reinforcement learning approach |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |