CN112821940B - Satellite network dynamic routing method based on inter-satellite link attribute - Google Patents

Abstract

The invention relates to the field of satellite communication, in particular to a satellite network dynamic routing method based on inter-satellite link attributes; the method comprises the steps of collecting a static snapshot sequence diagram of a satellite network, and constructing a space-time evolution diagram of the satellite network; the method comprises the steps that state information of satellite nodes collected by a controller node in real time is used for respectively calculating a link SNR, link survival time and a dynamic utility value of a satellite cache; a weighted satellite network space-time evolution diagram is constructed by assigning weights to the dynamic utility values of the link attributes among the satellites by adopting a multi-attribute decision-based adaptive maximum dispersion algorithm; acquiring an end-to-end reachable path of the satellite based on the weighted satellite network space-time evolution diagram, and establishing an optimization model of link utility; and the controller node selects the transmission path by using the optimization model and determines the reliable transmission path from end to end of the satellite. The invention can optimize the system routing path according to the link state information, thereby improving the network throughput and reducing the packet loss rate, and simultaneously has higher dynamic adaptability.

Description

A Dynamic Routing Method for Satellite Networks Based on Inter-satellite Link Properties

technical field

The invention relates to the field of satellite communications, in particular to a satellite network dynamic routing method based on inter-satellite link attributes.

Background technique

With the integration and development of satellite network and mobile communication technology, satellite constellations are gradually developing towards a large-scale, high-density, multi-layer trend, such as Oneweb, SpaceX and Telesat. The introduction of innovative network technologies such as SDN/NFV provides support for expanding satellite network applications and building a 6G-oriented integrated space-ground network. For Low Earth Orbit (LEO) networks, the establishment of Inter-Satellite Link (ISL) can improve the flexibility of satellite networking routing and meet the application requirements of high bandwidth and low latency. However, the increase in the scale of satellites, the enhancement of network heterogeneity and the high dynamics of satellites make the inter-satellite communication environment more and more complex. The key issue.

In response to this problem, researchers introduced the idea of on-demand routing to propose a location-based on-demand routing protocol, and some researchers proposed an SDN-based spatial information network management algorithm, and introduced a spatiotemporal evolution graph to describe the dynamic changes of satellite topology to achieve real-time network fine-grained routing . However, in the process of describing the dynamic network topology in the above scheme, the description of the dynamic topology of the satellite network is only an aggregation of static discrete snapshots. It is assumed that the attributes of links and nodes do not change within a known time period. When the network changes frequently, There is a problem that the topology information is not updated in time, which seriously affects the accuracy of the path selection of the dynamic routing algorithm. At the same time, limited by the computing power on the satellite, assuming that the snapshot interval is small enough to keep the network topology unchanged, it will bring huge challenges to satellite storage. As the scale of satellite constellation increases, the number of satellite nodes continues to increase, the link status becomes more complex, and the problem of unreliable routing caused by inaccurate topology information becomes more prominent.

SUMMARY OF THE INVENTION

In order to solve the above problem, the present invention provides a satellite network dynamic routing method based on inter-satellite link attributes.

The dynamic routing method of satellite network based on the attribute of inter-satellite link includes the following steps:

S1. The controller node collects a series of static snapshot sequence diagrams of the satellite network, and constructs a satellite network spatiotemporal evolution diagram according to the time series division, thereby obtaining a continuous dynamic satellite network topology;

S2, based on the state information of the satellite node collected in real time by the controller node, calculate the dynamic utility value of each inter-satellite link attribute, namely link SNR, link lifetime and satellite cache respectively;

S3. The adaptive maximum dispersion algorithm based on multi-attribute decision-making is used to give weight to the dynamic utility value of each inter-satellite link attribute, and to construct a weighted satellite network spatiotemporal evolution map;

S4, obtaining the end-to-end reachable path of the satellite based on the weighted satellite network spatiotemporal evolution map, and establishing an optimization model of link utility;

S5. The controller node selects the transmission path by using the optimization model of link utility, and determines the end-to-end reliable transmission path of the satellite.

Beneficial effects of the present invention:

1. The present invention constructs a satellite network weighted space-time evolution diagram based on the inter-satellite link state information, accurately depicts the continuous change of the satellite network dynamic topology, and helps to improve the dynamic adaptability of the routing algorithm;

2. The present invention analyzes and models the link attribute inter-satellite link SNR, link lifetime and satellite node cache, etc., and uses adaptive dispersion to give weight to the dynamic utility value of each inter-satellite link attribute, so as to realize the chain link. It can quantify the quality of the road, and use the multi-attribute decision-making theory to establish a link utility evaluation model to determine the attribute weight of each link, realize the quantification of the link quality, and optimize the routing path according to the link quality to ensure the reliability of data transmission.

Description of drawings

The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

1 is an overall flowchart of a method for dynamic routing of satellite networks based on inter-satellite link attributes according to an embodiment of the present invention;

Fig. 2 is a satellite network spatiotemporal evolution diagram based on virtual network topology provided by an embodiment of the present invention;

3 is a corresponding snapshot-based satellite network spatiotemporal evolution diagram provided by an embodiment of the present invention;

4 is an analysis diagram of adjacent satellite position points on a virtual orbit plane provided by an embodiment of the present invention;

FIG. 5 is a change diagram of on-off time of an inter-satellite link according to an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

1 is a flowchart of a method for dynamic routing of satellite networks based on inter-satellite link attributes according to an embodiment of the present invention. The method includes but is not limited to the following steps:

S1. The controller node collects a series of static snapshot sequence diagrams of the satellite network, and constructs a satellite network spatiotemporal evolution diagram according to the time series division, thereby obtaining a continuous dynamic satellite network topology;

S2, based on the state information of the satellite node collected in real time by the controller node, calculate the dynamic utility value of each inter-satellite link attribute, namely link SNR, link lifetime and satellite cache respectively;

S3. The adaptive maximum dispersion algorithm based on multi-attribute decision-making is used to give weight to the dynamic utility value of each inter-satellite link attribute, and to construct a weighted satellite network spatiotemporal evolution map;

S4, obtaining the end-to-end reachable path of the satellite based on the weighted satellite network spatiotemporal evolution map, and establishing an optimization model of link utility;

S5. The controller node selects the transmission path by using the optimization model of link utility, and determines the end-to-end reliable transmission path of the satellite.

In order to make the method of the present invention clearer and more complete, each step is described in detail next:

In step S1, a continuous dynamic satellite network topology needs to be established; in the embodiment of the present invention, a time dimension is added on the basis of the virtual network topology according to the space-time evolution theory, a satellite network space-time evolution diagram is constructed, and a continuous dynamic satellite network topology is obtained;

Specifically, based on the spatiotemporal evolution graph theory, a time dimension parameter is added to the virtual network topology, and the static snapshot sequence graph is converted into a spatiotemporal evolution graph to describe the topology change process of the satellite network. Using the method of generating topological snapshots at equal time intervals, the satellite operation period T=[t ₀ , t _K ] is divided into K time slots, T={τ ₁ ,…,τ _k ,…,τ _K }, τ _k = [t _k-1 , t _k ], t _k-1 and t _k represent two consecutive moments in [t ₀ , t _K ].

FIG. 2 is a space-time evolution diagram of a satellite network based on a virtual network topology provided by an embodiment of the present invention; as shown in FIG. 2 , the satellite network is represented as a space-time evolution diagram G=(S, E, T), a series of The static topological subgraph of is represented as {G ₁ , G ₂ ,...,G _K }, where S={s ₁ ,s ₂ ,...,s _N } represents the set of satellite nodes, and E represents the satellite network Satellite link set, in which the topology snapshot diagram at time t _k is represented as G _k = {S _k , E _k }, three sub-graphs are taken as an example in FIG. 2 , sub-graph G ₁ ie the satellite network topology at time t ₁ includes Satellite nodes s ₁ , s ₂ ,..., s ₅ ; the link relationship is that satellite s ₅ is connected to satellite s ₃ , satellite s ₃ is connected to satellite s ₁ , satellite s ₁ is connected to satellite s ₂ , and satellite s ₂ is connected to satellite s ₄ ; After experiencing different moments, the link of the satellite changes, and the dynamic space-time evolution diagram formed by the static snapshot sequence diagram at each moment can show the transformation process of the link of the satellite and the satellite node itself.

3 is a corresponding snapshot-based satellite network space-time evolution diagram provided by an embodiment of the present invention; as shown in FIG. 3 , there are K+1 layers in the space-time evolution diagram G, and each layer includes N satellite nodes, with a total of N ( K+1) nodes, and the topology change process of the time-varying network is simulated based on this graph.

As shown in Figure ³ , assuming that the data packet is to be transmitted from the source node s ₁ to the destination node s ₅ , _two routing strategies (the dense dashed line and the sparse dashed line from S10 to ^S53 can be found through the spatiotemporal evolution graph G ₎ ), the data packet can be transmitted within this period of time.

In step S2, the embodiment of the present invention needs to calculate the attributes of each inter-satellite link, including the SNR of the inter-satellite link, the link lifetime and the dynamic utility value cached by the satellite node, based on the state information of the satellite nodes collected in real time by the controller node. ;

Specifically, the link SNR is firstly quantified and modeled. According to Shannon's theorem, the SNR of the inter-satellite link determines the maximum information rate of error-free and reliable transmission of the link. When the SNR is less than the threshold, the network transmission is likely to be interrupted and cannot be guaranteed. The transmission quality of the routing path.

Model the signal transmission process as:

Among them, Y _ij represents the final signal, P _t represents the transmission power, _{Li ij} represents the inter-satellite distance, γ represents the path loss index, h _ij represents the link loss factor, X _i represents the transmitted signal strength, and N _ij represents the variance σ _n The additive white Gaussian noise of ² shows that the statistical characteristics of laser transmission are expressed in the link loss factor h _ij .

The loss of the laser inter-satellite link in the free space link mainly includes the geometric loss of the tracking error that the receiver is not in the center of the Gaussian beam and the path loss caused by long-distance transmission. The link loss factor h _ij is expressed as:

Among them, θ represents the tracking error angle, ω ₀ represents the half-width of the beam divergence angle of the Gaussian beam, and the inter-satellite laser link distance is Li _ij (t). When the physical parameters of satellite nodes are determined, the link loss factor is mainly related to the relative positions between satellite nodes, and the probability density function obeyed is:

The SNR of the inter-satellite link between satellite i and satellite j at any time t is expressed as:

Among them, the instantaneous position of the satellite L _s (t)=[x(t), y(t), z(t)] is uniquely determined according to the satellite Kepler orbital parameters, and the Euclidean distance formula of the inter-satellite link can be obtained by using the Euclidean distance formula The distance is:

From the distribution law obeyed by h, it can be deduced that |h _ij (t)| ² follows the non-central chi-square distribution, and its probability density function is:

When the SNR of the channel is less than the given threshold α, the probability of interruption of data will occur in the process of transmission, and the inter-satellite link cannot guarantee the reliable transmission of data packets. The interruption event is expressed as:

The outage probability of a packet with an SNR threshold α between satellite i and satellite j is:

In order to ensure the effective transmission of the data packet, the dynamic utility function U(s) of the SNR of the inter-satellite link attribute at any time t is defined as the probability that the data packet can be successfully transmitted, which is expressed as:

U(s)=1-P _r {SNR _ij (t)<α}=1-p _ij (t)

Further, quantitative modeling is performed on the lifetime of the inter-satellite link, as shown in Figure 4, Δω _f is the two satellites S _i,j and S _i+1,j that can establish an inter-satellite link between adjacent orbital planes. The phase difference ω _β is the corresponding phase angle when the orbital polar area dimension is β, ω(t) represents the phase angle corresponding to the satellite at time t, and the Δω _f value under the conditions of the polar orbit constellation system and the Walker constellation system can be expressed for:

where NL is the number of orbital planes, _ML is the number of satellites in each orbital plane, and _F is the phase factor in the Walker constellation. When the satellites at either end of the ISL enter the polar region with an angular velocity v _s , the ISL will be interrupted, and when the satellites at both ends exit the polar region, the link will be re-established, then it can be concluded that the duration of the ISL interruption is:

As shown in Figure 5, Tr represents the on-off period of intermittent ISL, that is, the time for the satellite to revolve around the earth once, and _{t b} represents the moment when one end of the link enters the polar region. The calculation method is t _b =ω _β /v _s .

Based on the above analysis, the survival time function of intermittent ISL can be derived:

The dynamic utility function of link lifetime at any time t is defined as:

Further, quantitative modeling is performed on the satellite node cache. According to the queuing theory model, the packet arrival rate follows a Poisson distribution with an average rate of λ, and A(t) represents the number of packets arriving in the time period t. The probability function of (t)=k _t is expressed as:

V_n过程表示数据包独立处理时间。且D(t)＝max{n:V_n≤t}表示t时间内节点处理的数据包数目，且有：In the process of data transmission, the service time of each data packet obeys the independent and identical distribution function, the distribution function is set to B(t), and v _n is defined as the processing time of the nth data packet,

The _Vn process represents the packet independent processing time. And D(t)=max{n:V _n ≤t} represents the number of data packets processed by the node within t time, and there are:

P(D(t)=n)= _Bn (t)-Bn ₊₁ (t)= _Cn (t)

Where B _n (t) is the n-fold convolution of B(t), then at time t, the packet queue length X(t) can be expressed as:

X(t)=m+A(t)-D(t)

Among them, m is the remaining number of data packets of the receiving satellite node at time t. Solve the processing probability of the current data queue X(t):

When optimizing the data transmission path, the greater the probability of data queue processing, the more suitable the data packet transmission is. Therefore, the dynamic utility function of the cache capacity of satellite nodes is defined as:

It can be understood that, in the embodiment of the present invention, the fixed attribute value in the traditional technology is abandoned, but the inter-satellite link attribute is described as a function of time, and the dynamic utility of each attribute is described by the time function. The accuracy of the obtained link attribute utility value is improved, and the routing algorithm is more adaptable to the dynamic change of the satellite network.

In step S3, the adaptive maximum dispersion algorithm based on multi-attribute decision-making is used to give weight to the dynamic utility value of each inter-satellite link attribute. During this period, the evaluation value of each inter-satellite link attribute needs to be calculated, and A decision matrix is constructed based on each evaluation value of the attribute of each inter-satellite link; the dispersion value of each evaluation value in the decision matrix on the current link and other links is calculated, and all attribute parameters in all candidates are obtained. The total dispersion value between transmission links; the objective function to maximize the total dispersion value is established, and the weight value of each inter-satellite link attribute is solved by using the Lagrangian function.

As for how to calculate the evaluation value of each inter-satellite link attribute, the present invention adopts a multi-attribute utility function to quantitatively evaluate the quality of the inter-satellite link, in order to accurately quantify the decision attributes such as link SNR, link lifetime and satellite node cache. Influence on the quality of routing links, based on the utility function of each attribute and the multi-attribute utility model, a multi-attribute utility function is designed to quantitatively evaluate the quality of the inter-satellite link. Multi-attribute decision-making can effectively solve the problem of optimal alternative selection under various decision-making attributes. According to the multi-attribute decision-making theory, the multi-attribute utility function needs to have the following characteristics:

Under the premise of satisfying the above constraints, the utility function that can evaluate the quality of the inter-satellite link is defined as follows:

表示链路l_ij第ε_i个决策属性权重，且

表示第ε_i个属性

的效用值。Among them, z is the number of attributes that affect the reliability decision-making of link l _ij ,

represents the weight of the ε _i -th decision attribute of the link l _ij , and

represents the ε _i -th attribute

utility value.

Through the analysis of the attribute modeling of the inter-satellite link, its utility functions U(s), U(l), U(b) can be obtained respectively, and the constraints of the multi-attribute utility function can be satisfied. The link utility between satellite i and satellite j can be expressed as:

Since the value of each attribute utility function is between [0, 1], the link utility value U _ij (x) is in the range of [0, 1], w _s ^ij , w _l ^ij and w _b ^ij are the links respectively SNR, the link lifetime and the weight of the node cache decision attribute, and satisfy _ws ^ij +w _l ^ij +w _b ^ij =1. The weight distribution is the key to ensure the effectiveness of the utility function. If an attribute has almost no difference on all feasible links, it means that the attribute has little influence on the decision-making process and should be given a smaller weight. If an attribute can make the attribute values of all links have a large deviation, it means that it plays an important role in decision-making and ranking, and it needs to be given a large weight.

链路SNR、链路生存时间和节点缓存，依次表示为A₁，A₂和A₃。The SDN controller can construct a spatiotemporal evolution map through the global network topology map, and determine p reachable paths from the source satellite node s to the destination satellite node d, and express this set as R(s,d)={R ₁ ,R ₂ , ...,R _p }, each reachable path includes g links, then the p-th reachable path can be expressed as R _p ={l ₁ ,l ₂ ,...,l _k ,...,l _g }. ISL decision attributes

Link SNR, link lifetime and node cache are denoted as A ₁ , A ₂ and A ₃ in sequence.

According to the above description, considering the different states of each node in the satellite network, the weight of each decision attribute of each path R _p is calculated based on the adaptive dispersion maximization algorithm. The specific algorithm steps are as follows:

计算对应链路属性评估值

₁ : According to the link utility of each link lk in each decision attribute ε _i

Calculate the corresponding link attribute evaluation value

再按照决策属性权重建立出更新后的决策矩阵Ω，依次表示为：2: Establish an initial decision _matrix with the link utility of each link lk in each decision attribute ε _i

Then, the updated decision matrix Ω is established according to the decision attribute weight, which is expressed as:

3: Calculate the attribute parameter evaluation value of the link _lk :

在链路l_k与R_p其他链路l_k′(k≠k′)的离差值

4: Calculated property parameters

The dispersion value between link l _k and R _p other links l _k' (k≠k')

表示第ε_i个决策属性，可以理解的是，本实施例中的ε_i与卫星表征i不是相同参数。5：计算属性参数

的总离差值：

Among them, ε _i here is some specific value, for example ε _i =1, 2, 3, use

represents the ε _i -th decision attribute. It can be understood that ε _i in this embodiment is not the same parameter as the satellite representation i. 5: Calculated property parameters

The total dispersion of :

6: Calculate the total dispersion value e(w) of all attribute parameters between all candidate transmission links:

7: Establish an objective function that maximizes the total dispersion of all attribute parameters among all candidate transmission links as the goal:

8: Based on the objective function, construct the corresponding Lagrangian function:

The present invention solves the maximum total dispersion value model by using the Lagrangian model, and can quickly and comprehensively solve the corresponding optimal value.

和

9: Calculate the partial derivative of the Lagrangian function

and

10: Let the partial derivative

11: Obtain three weight values corresponding to the three inter-satellite link attributes

In step S4, in the embodiment of the present invention, a weighted satellite network spatiotemporal evolution graph is constructed according to the weight value of the link attribute, and an optimization model U(R) of the link utility is established based on the end-to-end reachable path obtained by the evolution graph model. (s,d));

Specifically, the path 1 represented by the dense dashed line and the path 2 represented by the sparse dashed line in Fig. 3, the end-to-end reachable path obtained by the weighted satellite network spatiotemporal evolution graph model, the optimization model of the link utility can be established, and Design path selection methods. Before the control plane sends flow rules, the controller will make routing decisions based on the utility of each path. In the p reachable paths R(s,d) from the satellite node s to the satellite node d, for any given route R _p , the number of links forming its route is g, and for any one of the inter-satellite links _lk The utility value is:

Because the links are different, the path utilities formed by multiple links are also different. Then it is defined that the utility of each path is equal to the utility value of the smallest link of all links in the path, and the link utility optimization model is expressed as:

in:

The final controller selects the path with the greatest utility as the packet transmission path, which can be expressed as:

In step S5, the controller node in the embodiment of the present invention selects the transmission path by using the optimization model of link utility, and determines the end-to-end reliable transmission path of the satellite. The controller node calculates the utility value of each path in the candidate path set, and takes the path with the largest utility value as the link transmission optimization path.

In some embodiments, the controller node may utilize a weighted satellite network spatiotemporal evolution model, and the designed reliable routing algorithm steps based on link utility are as follows:

1: Initialize the orbit status information of the satellite node;

2: The controller constructs a space-time evolution graph G=(S, E, T) based on the orbital operation law;

3: Determine a candidate path R(s,d)={R ₁ , R ₂ ,...,R _p } from S _s to S _d according to G;

4: Determine the link set of candidate paths: R _p (p=1, 2,...,p): R _p ={l ₁ ,l ₂ ,...,l _k };

5: For each candidate path, determine the utility value of the link attribute on the reachable path based on the adaptive dispersion algorithm;

6: For each link in the candidate path, calculate the link attribute weight according to the link attribute utility and attribute weight

7: Establish a weighted spatiotemporal evolution graph based on the link utility value;

8: Calculate the utility U(R(s,d)) of each path in the candidate path set;

9: The optimal path is the path with the largest utility value: maxU(R _p (s, d));

10: Obtain the link transmission optimized path Rp.

The invention can optimize the routing path of the system according to the link state information, thereby improving the network throughput and reducing the packet loss rate, and at the same time, it has high dynamic adaptability.

In the description of the present invention, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top" "," "inside", "outside", "front", "center", "both ends", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present invention and The description is simplified rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

In the present invention, unless otherwise expressly specified and limited, terms such as "installation", "arrangement", "connection", "fixation" and "rotation" should be understood in a broad sense, for example, it may be a fixed connection or a It can be a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between the two elements, Unless otherwise clearly defined, those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, and substitutions can be made in these embodiments without departing from the principle and spirit of the invention and modifications, the scope of the present invention is defined by the appended claims and their equivalents.

Claims (6)

1. a kind of satellite network dynamic routing method based on inter-satellite link attribute, is characterized in that, comprises the following steps: S1. The controller node collects a series of static snapshot sequence diagrams of the satellite network, and constructs a satellite network spatiotemporal evolution diagram according to the time series division, thereby obtaining a continuous dynamic satellite network topology; S2, based on the state information of the satellite node collected in real time by the controller node, calculate the dynamic utility value of each inter-satellite link attribute, namely link SNR, link lifetime and satellite cache respectively; The calculation method of the dynamic utility value of the link SNR in the inter-satellite link attribute includes: U(s)=1-P _r {SNR _ij (t)<α}=1-p _ij (t). Among them, U(s) represents the dynamic utility value of the SNR of the inter-satellite link; SNR _ij (t) SNR of the inter-satellite link between satellite i and satellite j at any time t, P _r {SNR _ij (t)<α} Represents the interruption event of data in the transmission process when the SNR of the channel is less than a given threshold α; p _ij (t) represents the interruption probability of a packet whose SNR threshold is α between satellite i and satellite j; The calculation method of the dynamic utility value of the link lifetime in the inter-satellite link attribute includes:

Among them, U(l) represents the dynamic utility value of the link lifetime; l _ij (t) is the lifetime function of the intermittent inter-satellite link, and T _r represents the on-off period of the intermittent inter-satellite link, that is, the satellite orbits the earth. a week; The calculation methods of the dynamic utility value of the satellite cache in the inter-satellite link attribute include:

Among them, U(b) represents the dynamic utility value of the satellite cache;

is the processing probability of the current data queue X(t), m is the remaining number of data packets of the receiving satellite at time t; S3. The adaptive maximum dispersion algorithm based on multi-attribute decision-making is used to give weight to the dynamic utility value of each inter-satellite link attribute, and to construct a weighted satellite network spatiotemporal evolution map; S4, obtaining the end-to-end reachable path of the satellite based on the weighted satellite network spatiotemporal evolution map, and establishing an optimization model of link utility; S5. The controller node selects the transmission path by using the optimization model of link utility, and determines the end-to-end reliable transmission path of the satellite. 2. a kind of satellite network dynamic routing method based on inter-satellite link attribute according to claim 1, is characterized in that, the construction process of described continuous dynamic satellite network topology comprises according to space-time evolution theory in the foundation of virtual network topology The time dimension is added to the top of the satellite network, and the space-time evolution map of the satellite network is constructed; the method of generating topology snapshots at equal time intervals is used to divide the satellite operation cycle into multiple time slots; each time slot is filled with satellite nodes and satellite network chains. road. 3. a kind of satellite network dynamic routing method based on inter-satellite link attribute according to claim 1, is characterized in that, described adopting the self-adaptive maximum dispersion algorithm based on multi-attribute decision-making is each inter-satellite link attribute The dynamic utility value given weights include: Calculate the evaluation value of each inter-satellite link attribute, and construct a decision matrix based on each evaluation value of each inter-satellite link attribute; Calculate the dispersion value of each evaluation value in the decision matrix on the current link and other links, and obtain the total dispersion value of all attribute parameters between all candidate transmission links; The objective function to maximize the total dispersion value is established, and the weight value of each inter-satellite link attribute is obtained by using the Lagrangian function. 4. a kind of satellite network dynamic routing method based on inter-satellite link attribute according to claim 3, is characterized in that, the calculation formula of the evaluation value of described inter-satellite link attribute comprises:

Among them, U(x) represents the evaluation value of the attributes of the inter-satellite link; z is the number of attributes that affect the reliability of the link l _ij ;

represents the weight of the ε _i -th decision attribute of the link l _ij , and

represents the ε _i -th attribute

utility value. 5. a kind of satellite network dynamic routing method based on inter-satellite link attribute according to claim 3, is characterized in that, the representation of the optimization model of described link utility comprises:

Among them, U(R(s,d)) represents the optimization model of link utility; R(s,d) represents p reachable paths from satellite s to satellite node d;

is the utility value of any one of the inter-satellite links _lk ,

represents the dynamic utility value of the link SNR of the inter-satellite link _lk ,

is the dynamic utility value representing the link lifetime of the inter-satellite link _lk ,

Represents the dynamic utility value of the satellite buffer of the inter-satellite link _lk ;

Indicates the weight of the link SNR in the inter-satellite link attribute;

Indicates the weight of the link lifetime in the inter-satellite link attribute;

Represents the weight of the satellite cache in the inter-satellite link attribute; k represents the inter-satellite link l _k ; g is any given route Rp, the number of links forming its route. 6. A kind of satellite network dynamic routing method based on inter-satellite link attribute according to claim 1, it is characterized in that, the process of using the optimization model of link utility to select the transmission path comprises that the controller node calculates the candidate The utility value of each path in the path set, and the path with the largest utility value is used as the link transmission optimization path.

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