CN103634842B - Method for routing between a kind of distributed satellite network group - Google Patents

Abstract

The present invention provides method for routing between a kind of distributed satellite network group, including: when in distributed satellite network source satellite group exist data need to send time, at the primary of the respective satellite group that route requests is sent in distributed network；When route requests often arrives a satellite group primary, collect the information of satellite, and pheromone value in AODV Routing Protocol；According to down hop selection algorithm, calculate route requests and will be sent to the probability of each satellite, from each satellite, according to each satellite probability calculated, select to send the down hop satellite of route requests；Often through a satellite, according to chain-circuit time delay and link available bandwidth, update local message element, according to local message element, select to send the down hop satellite that route please be asked；After purpose satellite receives route requests, produce routing reply, thus set up the reverse route between source satellite and purpose satellite.Present invention reduces communication delay, improve link available bandwidth, improve the communication quality of link.

Description

Method for routing between a kind of distributed satellite network group

Technical field

The invention belongs to group of stars networking technology area, relate to method for routing between a kind of distributed satellite network group.

Background technology

At present, existing satellite routing algorithm is divided into virtual topology routing algorithm and virtual joint according to topology of networks Point routing algorithm two class.These satellite routing algorithms design for low orbit satellite mostly, and constellation change in topology is very fast, and does not has Consider the state of link.And the topology of a distributed group of stars is the most stable, so traditional Routing Protocol can not directly be suitable for In distributed group of stars network.

Summary of the invention

The present invention is directed to the proposition of problem above, and method for routing between the distributed satellite network group proposed, solve point The problem of cloth group of stars route.

On the one hand, the invention provides method for routing between a kind of distributed satellite network group, including:

When in distributed satellite network source satellite group exist data need send time, route requests is sent to distributed network At the primary of the respective satellite group in network；

When described route requests often arrives a satellite group primary, collect the information of described satellite, and AODV route is assisted Pheromone value in view；

According to down hop selection algorithm, calculate described route requests and will be sent to the probability of each satellite, defend from each In star, according to the probability of each satellite calculated, select to send the down hop satellite of route requests；

Often through a satellite, according to chain-circuit time delay and link available bandwidth, update local message element, according to described local Pheromone, selects to send the down hop satellite that route please be asked；

When described purpose satellite or arrive purpose Satellite Road by intermediate, satellite receive described route requests after, produce route Reply, thus set up the reverse route between source satellite and purpose satellite.

Further, this distributed satellite network method for routing, also include:

After the route set up between source satellite and purpose satellite, realize route maintenance by hello message packet, institute State interpolation energy purpose in hello message packet, dynamically notify the residue situation of neighbor node energy, carry during for selecting and routeing For energy information the most accurately.

Further, above-mentioned down hop selection algorithm is specially ant algorithm, particularly as follows:

$P_{\mathrm{ij}}^k\left(t\right)=\left\{\begin{array}{cc}\frac{{\left[{\mathrm{\τ}}_{\mathrm{ij}}\left(t\right)\right]}^{\mathrm{\α}}\×{\left[{\mathrm{\η}}_{\mathrm{ij}}\left(t\right)\right]}^{\mathrm{\β}}}{\underset{Z\⋐{\mathrm{allowed}}_k}{\mathrm{\Σ}}{\left[{\mathrm{\τ}}_{\mathrm{iz}}\left(t\right)\right]}^{\mathrm{\α}}\×{\left[{\mathrm{\η}}_{\mathrm{iz}}\left(t\right)\right]}^{\mathrm{\β}}}& j\⊂⃒{\mathrm{tabu}}_k\\ 0& \mathrm{otherwise}\end{array}\right.$

Wherein, in formulaPath (i, probability j) advanced is selected for t Formica fusca k；α is the pheromone factor, characterizes letter The significance level of breath element；η_ijT () is heuristic function, equal to the inverse of node i Yu node j distance, characterize path (i, power j) Weight, β is the heuristic information factor, characterizes the significance level of heuristic information；tabu_k(k=1,2 ..., m) it is the taboo list of Formica fusca k, note Record the node that Formica fusca k has passed by；allowed_k={c-tabu_kRepresent that next step allows the node selected at t Formica fusca k.

Further, above-mentioned according to chain-circuit time delay with link available bandwidth, update local message element, particularly as follows:

Update formula according to link weight, calculate local message elementWherein, link weight renewal formula is:

$\mathrm{\Δ}{\mathrm{\τ}}_{\mathrm{ij}}^k\left(t\right)=\left\{\begin{array}{cc}\frac{Q+w_{\mathrm{ij}}}{d_{\mathrm{ij}}}& w_{\mathrm{ij}}\≤w\\ \frac{Q-w_{\mathrm{ij}}}{d_{\mathrm{ij}}}& \mathrm{Else}\end{array}\right.$

Wherein, Q represents the enhancing coefficient of pheromone；W represents the threshold value of link weight, and its initial value is w₀；d_ijRepresent This circulation in kth Formica fusca walked path (i, j), w_ijRepresent node i to link between neighbor node j (i, weight j), Its expression formula is as follows:

$w_{\mathrm{ij}}=\frac{D{(i,j)}^{{\mathrm{\α}}_{\text{1}}}}{\text{B}{(i,j)}^{{\mathrm{\β}}_1}}$

Wherein, D (i, j) represent link (i, j) on time delay, B (i, j) represent link (i, j) on available bandwidth, α₁With β₁Represent bandwidth and the relatively important coefficient of time delay respectively.

The invention have the advantages that, can be prevented effectively from that Link State is congested and that cause wait time delay increase etc. is asked Topic, improves router efficiency.

Accompanying drawing explanation

The flow chart of method for routing between a kind of distributed satellite network group that accompanying drawing 1 provides for the present invention；

Accompanying drawing 2 is the flow chart that the ant group algorithm of the improvement of the present invention and AODV agreement are applied to satellite network；

The equivalent topologies structure chart of the Samsung group communication that accompanying drawing 3 is taked for present invention emulation；

Accompanying drawing 4 emulates the time slot dividing figure taked for the present invention；

Accompanying drawing 5 emulates broadband bottleneck comparison diagram for the present invention；

Accompanying drawing 6 is simulation end to end time delay comparison diagram of the present invention.

Detailed description of the invention

The detailed description of the invention of the present invention is described in detail below in conjunction with technical scheme and accompanying drawing.

For existing Satellite Network Routing Algorithms using path as route evaluation criterion, nearest path is caused to be differed Surely it is the feature in optimum path, proposes a kind of route selection algorithm rapidly and efficiently.The method considers the state of link, as can By bandwidth, propagation delay time and the bit error rate etc., and source is driven Routing Protocol (Ad hoc on-demand distance vector Routing, AODV) application is wherein, it is ensured that under the optimal situation of path, reduce the time delay of satellite network communications, reach communication with this Optimum purpose.

As it is shown in figure 1, a kind of distributed satellite network group of stars method for routing of the embodiment of the present invention, including:

Step 1: when distributed satellite network group's Satellite exist data need send time, route requests is sent to distribution The primary of the respective satellite group in formula network, is set up by primary and route between group.

Step 2: when described route requests often arrives a satellite group primary, collects the information of described satellite group primary, with And pheromone value in AODV Routing Protocol.

Step 3: according to down hop selection algorithm, calculates described route requests and will be sent to the general of each satellite group primary Rate, from each satellite group primary, according to the probability of each satellite group primary calculated, selects to send the down hop of route requests Satellite.

Concrete: can utilize ant algorithm, thus select down hop selection algorithm, concrete process is as follows:

Set constant N, w₀, Q, ρ, n, α, β, and one empty taboo list tabu is set for every Formica fusca_k。

Give Formica fusca k by below equation (1) and select to move to the probability of adjacent node j in node i:

$P_{\mathrm{ij}}^k\left(t\right)=\left\{\begin{array}{cc}\frac{{\left[{\mathrm{\τ}}_{\mathrm{ij}}\left(t\right)\right]}^{\mathrm{\α}}\×{\left[{\mathrm{\η}}_{\mathrm{ij}}\left(t\right)\right]}^{\mathrm{\β}}}{\underset{Z\⋐{\mathrm{allowed}}_k}{\mathrm{\Σ}}{\left[{\mathrm{\τ}}_{\mathrm{iz}}\left(t\right)\right]}^{\mathrm{\α}}\×{\left[{\mathrm{\η}}_{\mathrm{iz}}\left(t\right)\right]}^{\mathrm{\β}}}& j\⊂⃒{\mathrm{tabu}}_k\\ 0& \mathrm{otherwise}\end{array}\right.---\left(1\right)$

Wherein, in formulaPath (i, probability j) advanced is selected for t Formica fusca k；α is the pheromone factor, characterizes The significance level of pheromone；η_ijT () is heuristic function, equal to the inverse of node i Yu node j distance, i.e. η_ij(t)=1/d_ij, table Levy path (i, weight j), for Formica fusca k, d_ijThe least, then η_ijT () is the biggest,The biggest；The β heuristic information factor, Characterize the significance level of heuristic information；tabu_k(k=1,2 ..., m) it is the taboo list of Formica fusca k, have recorded the joint that Formica fusca k has passed by Point；allowed_k={c-tabu_kRepresent that next step allows the node selected at t Formica fusca k.

Step 4: often through a satellite group primary, according to chain-circuit time delay and link available bandwidth, updates local message element, When described route requests arrive purpose satellite or arrive purpose Satellite Road by intermediate, satellite till.

Concrete process is as follows: As time goes on, after all Formica fuscas complete an iteration, walk pass by one's way to Formica fusca Pheromone on footpath is updated.First volatilize original pheromone, then increase the Formica fusca pheromone through path, pheromone More new formula as follows:

τ_ij(t+Δt)=(1-ρ)τ_ij(t)+τ_ij(Δt) (2)

${\mathrm{\τ}}_{\mathrm{ij}}\left(\mathrm{\Δt}\right)=\underset{k=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{\τ}}_{\mathrm{ij}}^k\left(\mathrm{\Δt}\right)---\left(3\right)$

Wherein: the volatility coefficient of pheromone on ρ (0≤ρ < 1) delegated path, the residual of pheromone that what (1-ρ) represented is because of Son, τ_ij(Δ t) represent path (i, j) on the size of pheromone increment, initial time τ_ij(Δt)=0。

If only considering bandwidth and 2 kinds of weight types of time delay in the embodiment of the present invention, then node i is between neighbor node j Weight w of link_ijIt is calculated as follows:

$w_{\mathrm{ij}}=\frac{D{(i,j)}^{{\mathrm{\&alpha;}}_{\text{1}}}}{\text{B}{(i,j)}^{{\mathrm{\&beta;}}_1}}---\left(4\right)$

Wherein D (i, j) represent link (i, j) on time delay, B (i, j) represent link (i, j) on available bandwidth.α₁And β₁ Represent bandwidth and the relative importance of time delay respectively, can be adjusted according to the specific requirement of bandwidth and time delay.

Group's routing algorithm is to make routing decision according to the size of pheromone on path, it is possible to by the state of link As affecting the factor of pheromone increment, increase or reduce pheromone increment according to the congestion situation of link.Start at algorithm Time, set initial link weight threshold w₀, when the link weight of process less than this threshold value, pheromone intensity Q is just Plus the weight of this link, the most just deduct this link weight.The pheromone that the link that so weight is less increases is the biggest, from And the probability chosen by follow-up Formica fusca is the biggest.Pheromone according to link weight update rule by formula (5) represent.

$\mathrm{\&Delta;}{\mathrm{\&tau;}}_{\mathrm{ij}}^k\left(t\right)=\left\{\begin{array}{cc}\frac{Q+w_{\mathrm{ij}}}{d_{\mathrm{ij}}}& w_{\mathrm{ij}}\&le;w\\ \frac{Q-w_{\mathrm{ij}}}{d_{\mathrm{ij}}}& \mathrm{Else}\end{array}\right.---\left(5\right)$

Wherein Q represents the enhancing coefficient of pheromone；w_ijRepresent link (i, weight j)；W represents the threshold value of link weight, Its initial value is w₀；d_ijThe expression path that kth Formica fusca is walked in this circulates (i, j).

Step 5: described purpose satellite or arrive purpose Satellite Road by intermediate, satellite receive described route requests after, produce Routing reply, thus set up the reverse route between source satellite and purpose satellite.

Step 6: after setting up initial route between satellite and purpose satellite, realize road by hello message packet By safeguarding, described hello message packet adds energy purpose, dynamically notifies the residue situation of neighbor node energy, for choosing Routing by time energy information the most accurately is provided.

As in figure 2 it is shown, the ant group algorithm of the embodiment of the present invention and AODV agreement are applied to satellite network flow chart, concrete Process is as follows: when a node receives Front ant for the first time when, and it can create a record in its routing table.This Individual record includes the parameters such as destination node address, next hop address, pheromone concentration.The wherein renewal process of pheromone concentration In, link weight is heavily taken into account.Node can select the next-hop node of this Front ant according to the concentration of pheromone, with The value of Shi Gengxin pheromone, this address of node can be joined in the route information table of oneself by Front ant.Before later The next-hop node of oneself is determined according to the pheromone value through staying later of the Formica fusca above, when Front ant arrives to Formica fusca After destination node, give destination node by the routing iinformation that it is entrained, destination node by this routing iinformation with existing Routing iinformation compares, and finds Optimization route.Destination node will send a backward successful Formica fusca to source node, backward success Optimal path through being found by Front ant is returned to destination node by Formica fusca, and updates the pheromone value being passed through route. So, one is just established by the route of source node to destination node.If Front ant missed one's aim within the rational time Node, then sent backward failed Formica fusca successively by the intermediate node of its process and discharge link successively.Use backward failed Formica fusca Avoid the unreachable problem in path using reverse path life span to cause.

The equivalent topologies structure chart of the Samsung group communication that accompanying drawing 3 is taked for present invention emulation, the artificial network in scheme is Use the common ground network that wire link connects.As landline network, each routing node in normal condition lower network Between whether to connect be changeless, i.e. the topology of network is changeless, and this is mainly due to the rule at networking initial stage Draw and determined.In simulation process, control each routing node break-make to circuit by artificial intervention, thus reach control The purpose of the topology of system and change network.Establishing simulation mobile-satellite net in NS2, the condition of network is as follows: 1. network is adopted Three constellations being combined with low rail with middle rail are in communication with each other model.The lowest rail is 5 780 kilometers of high pole orbits, every track 5 Satellite.Middle rail is two constellations, and each constellation is 4 10350 kilometers of high pole orbits, 2 satellites of every track.4. exist In low rail layer, every star only keeps inter-satellite link with four the most adjacent stars；In high rail layer, every star is only with adjacent Three satellites keep inter-satellite link.5. the switching of inter-satellite link occurs mainly in interlayer, between the lowest rail and middle rail star, and low rail During star selects with the principle that distance is the shortest, rail star sets up inter-satellite link.6. the length of time slot can be chosen according to the requirement of emulation. In this emulation, in order to improve simulation velocity, set each time slot length 5 minutes.

Fig. 4 is that the present invention emulates the time slot dividing figure taked, and concrete grammar is: if being divided in the whole system cycle in emulation The timeslice of dry a length of Δ t, is i.e. divided into N number of time slot, and the size of timeslice depends on the simulation accuracy that requirement reaches, time The least scheme that sheet is chosen is the best to the emulator of truth, and the precision of final simulation result is the highest.In simulation process, adopt Be taken at each time slot initially updates network topology.

During emulation, setting source node as a group of stars 1, destination node is a group of stars 2, iterations N=60, pheromone intensity Q=10, Volatility coefficient ρ=0.5, heuristic greedy method α=1, β=5, Formica fusca number n=20.During beginning, the pheromone concentration in each of the links is phase With, Formica fusca is randomly chosen path, after every time selecting a node, to two inter-node link of process according to path Time delay, bandwidth situation carries out Pheromone update, and Formica fusca hereafter selects path can be affected by former generation Formica fusca, alternates through n generation And then find optimal path.

Finally the satellite network set up having been carried out simple performance simulation and assessment, accompanying drawing 5 present invention emulates broadband bottleneck Comparison diagram, and accompanying drawing 6 is simulation end to end time delay comparison diagram of the present invention.

By the distributed satellite network method for routing of the present invention, by be applied to AODV agreement to improve based on link In the ant group algorithm of weight, this routing algorithm meets actual demand, has the strongest communication Route Selection meaning, and overcomes Traditional shortcoming ignoring link weight, reduces satellite network Route establishment time delay, improves satellite network communications efficiency.

The above, this is the present invention preferably detailed description of the invention, but protection scope of the present invention is not limited thereto, Any those familiar with the art in the technical scope that the invention discloses, according to technical scheme and Inventive concept equivalent or change in addition, all should contain within protection scope of the present invention.

Claims (2)

1. method for routing between a distributed satellite network group, it is characterised in that including:

When in distributed satellite network source satellite group exist data need send time, route requests is sent in distributed network Respective satellite group primary at；

When described route requests often arrives a satellite group primary, collect in the information of described satellite, and AODV Routing Protocol Pheromone value；

According to down hop selection algorithm, calculate described route requests and will be sent to the probability of each satellite, from each satellite, According to the probability of each satellite calculated, select to send the down hop satellite of route requests；

Often through a satellite, according to chain-circuit time delay and link available bandwidth, update local message element, according to described local message Element, the down hop satellite of selection transmission route requests:

Described according to chain-circuit time delay with link available bandwidth, update local message element, particularly as follows: update public affairs according to link weight Formula, calculates local message element

${\mathrm{\&Delta;\&tau;}}_{ij}^k\left(t\right)=\left\{\begin{array}{cc}\frac{Q+w_{ij}}{d_{ij}}& w_{ij}\&le;w\\ \frac{Q-w_{ij}}{d_{ij}}& Else\end{array}\right.$

Wherein, Q represents the enhancing coefficient of pheromone；W represents the threshold value of link weight, and its initial value is w₀；d_ijRepresent at this Path that in circulation, kth Formica fusca is walked (i, j),

w_ijRepresent node i to link between neighbor node j (its expression formula is as follows for i, weight j):

$w_{ij}=\frac{D{(i,j)}^{{\mathrm{\&alpha;}}_1}}{B{(i,j)}^{{\mathrm{\&beta;}}_1}}$

Wherein, D (i, j) represent link (i, j) on time delay, B (i, j) represent link (i, j) on available bandwidth, α₁And β₁Point Biao Shi bandwidth and the relatively important coefficient of time delay；

Described down hop selection algorithm is specially ant algorithm, particularly as follows:

Wherein, in formulaPath (i, probability j) advanced is selected for t Formica fusca k；α is the pheromone factor, characterization information element Significance level；η_ijT () is heuristic function, equal to the inverse of node i Yu node j distance, (β is for i, weight j) to characterize path The heuristic information factor, characterizes the significance level of heuristic information；tabu_k(k=1,2 ..., m) it is the taboo list of Formica fusca k, have recorded The node that Formica fusca k has passed by；allowed_k={ c-tabu_kRepresent that next step allows the node selected at t Formica fusca k；τ_ij T () is t path (i, j) upper pheromone, τ_izT () is t path (i, z) upper pheromone；η_izT () is heuristic function, etc. In the inverse of node i Yu node z distance, characterize path (i, weight z)；

When purpose satellite or arrive purpose Satellite Road by intermediate, satellite receive described route requests after, produce routing reply, from And set up the reverse route between source satellite and purpose satellite.

2. method for routing between a kind of distributed satellite network group as claimed in claim 1, it is characterised in that also include:

After the route set up between source satellite and purpose satellite, realize route maintenance by hello message packet.