CN104202724A - AANET combined routing algorithm based on geographical location information - Google Patents

Abstract

The invention discloses an AANET combined routing algorithm based on geographical location information. Greedy forwarding strategies and reactive routing in geographic routing are combined. Aiming at the high dynamic and low node density characteristics of an aviation ad-hoc network, the greedy forwarding strategies in the geographic routing is modified first, and new routing metric considers both the geographical locations of nodes and relative speed among nodes and eliminates unstable next-hop forwarding nodes. The algorithm combines good characteristics of traditional reactive routing, uses an RREQ/RREP mechanism to replace the periphery forwarding mechanism in the geographic routing, and routing void can be processed effectively. Compared with other methods, the algorithm combines the advantages of two algorithms and is more adaptive to the network environments of the aviation ad-hoc network.

Description

A kind of AANET joint route algorithm based on geographical location information

Technical field: routing algorithm

The present invention relates to the joint route algorithm based on geographical location information in a kind of AANET (aviation MANET), more specifically, relate to a kind of routing algorithm that geographic routing and reaction equation route are combined, and by optimally line of reasoning by the route metric of greedy forward mode improve the performance of network.

Background technology:

Route technology is one of aviation MANET key technology, and routing algorithm has determined the performance of whole network to a great extent.Typical Routing Protocol can be divided into two large classes: the Routing Protocol based on topological structure and the Routing Protocol based on geographical location information.Routing Protocol based on topological structure is known annexation and the link property between nodes by route exploration, carrys out thus to determine network route.It further can be divided into again active, type and mixed type route as required.Initiatively route adopts periodic routing broadcast to carry out exchanging routing information, the route of all nodes of given node maintenance the whole network, and effective routing exists all the time, and transmission delay is little, but its expense is large and take resource.Route, according to the needs of sending node, is carried out route discovery as required as required, take resource few, but time delay is larger.Mixing route combines the advantage of active route and passive route, and extensibility is better.Because modern Aviation aircraft has substantially all been equipped with GPS global positioning system, node can obtain geographical location information easily, and the Routing Protocol based on geographical location information gets most of the attention, and at aviation field, has broad application prospects.This quasi-protocol need to obtain the position of oneself in advance, and one jumps the position of neighbors and the position of destination node.It need to be before not sending packet maintaining routing list or set up path.Therefore,, even the in the situation that of network topology acute variation, geographical route also can keep good simplicity and extensibility.

In numerous geographical routes, greedy periphery stateless Routing Protocol (GPSR) is the wherein the most classical a kind of Routing Protocol being most widely used.GPSR agreement has two kinds of mode of operations, and first it be operated in greedy pattern, chosen distance destination node recently and than own to the near jumping neighbors of point of destination as down hop forward node.When there is route cavity, just automatically switch to periphery forward mode, first network topology is described as to plane graph, then forwards according to right-hand rule.Yet GPSR is faced with many problems while being applied to the air net of high dynamic topology, low node density.First the greedy forwarding strategies of GPSR is not considered the mobility of node, and next is taked periphery traversal to solve route cavity problem and is proved to be poor efficiency, causes that packet is a large amount of to be lost and time delay sharply increases under high dynamic environment.

Although proposed a large amount of Routing Protocol for MANETs at present, be seldom wherein to study for the specific objective of aviation MANET.Until in recent years, multi-hop wireless network was more and more paid attention in the research of aviation field, and these researchs are also to carry out for the demand of the different aspect of aviation MANET.A kind of multipath Doppler Routing Protocol (MUDOR) has been proposed in Australian AANET project, utilize the internodal relative velocity of Doppler frequency estimation to come between decision node to be mutually near or away from, and select the path of Doppler frequency shift value minimum to build route.This algorithm has effectively reduced network traffic load and the propagation delay in real-time traffic transmission.ARPAM is a mixed type Routing Protocol that is applied to commercial aviation network based on AODV, and this agreement utilizes positional information find shortest path and between source node and destination node, set up complete end-to-end path.In the NEWSKY of European Union project, used a kind of routing algorithm that (GLSR) shared in geographical load that is called, it utilizes pace, the tolerance that namely ratio of speed and queue time delay is selected as down hop, meet from destination node recently and add the principle of the shortest queue simultaneously, effectively alleviated the congestion problems in GPSR agreement.

Summary of the invention:

The object of the invention is for AANET topological structure dynamically high, the feature that node density is low, a kind of method for routing based on geographical location information being more suitable in this network is provided, the method combines the advantage of geographical route and reaction equation route effectively, and has optimized the greedy forward mode in geographical route.Figure of description 1 shows the basic flow sheet of this algorithm.

Joint route algorithm based on geography information is achieved in that

1. first, each node in network obtains relevant geographical location information, comprises the position of oneself, and one jumps position and the destination node positional information of neighbors.Can pass through respectively GPS global positioning system, beaconing mechanism and location-based service obtain.

2. when starting to communicate between node, be first operated in greedy forward mode, each node maintains the positional information that neighbor table that cycle upgrades is followed the tracks of a jumping neighbors.According to new route metric MDT (Minimum duration time), select down hop forward node.This route metric has considered position and the relative velocity of node, makes more efficient stable of the route chosen.

3. while running into route cavity (Figure of description 2 has been described the situation in route cavity) in repeating process, automatically switch to reaction equation route pattern, utilize RREQ/RREP mechanism to find available path.

4. once node is walked around hole region and is existed than the node oneself with less MDT value in its neighbors, turns back to greedy forward mode.

5. repeat above step, until packet arrives destination node.

Compare with other technology, the present invention has advantages of following:

1. because modern Aviation aircraft has substantially all been equipped with GPS global positioning system, node can obtain geographical location information easily, and the present invention has effectively utilized geography information.

2. improved route metric has not only been considered the geographic distance of node, has also considered that internodal relative velocity, this strategy make down hop forward node more reliable and more stable simultaneously, thereby improves communication quality, more adapts to high dynamic air communications environment.

3. utilize the RREQ/RREP mechanism of reaction equation route to substitute the periphery forward mode in GPSR agreement, avoided long routed path and route loop, more more effective and reliable than periphery traversal forwarding strategy.

4. the present invention combines the advantage of geographical route and active route, and has optimized its route metric.

Accompanying drawing explanation:

Read by reference to the accompanying drawings following detailed description in detail of the present invention, the present invention may be better understood and advantage and other features, wherein:

Fig. 1 shows the basic flow sheet of geographical joint route algorithm;

Fig. 2 shows the situation in route cavity.

Embodiment:

In order to understand better the present invention, will describe the specific embodiment of the present invention in detail below.

1. each node in network maintains a routing table, and table information comprises the position of oneself, and one jumps position and the destination node position of neighbors.Can pass through respectively GPS global positioning system, beaconing mechanism and location-based service obtain.

2. when starting to communicate between node, be first operated in greedy forward mode, each node maintains the positional information that neighbor table that cycle upgrades is followed the tracks of a jumping neighbors, then according to new route metric MDT, selects down hop forward node.

3. determine route metric MDT, the geographic distance S between nodes i and j below _i,jcan represent with following formula:

$S_{i,j}\left(t\right)=\sqrt{{(x_i\left(t\right)-x_i\left(t\right))}^2+{(y_i\left(t\right)-y_j\left(t\right))}^2+{(z_i\left(t\right)-z_j\left(t\right))}^2}---\left(1\right)$

Wherein, (x _i(t), x _j(t)), (y _i(t), y _j(t)), (z _i(t), z _j(t)) difference representation node i, j is at the position coordinates of current time t.

Internodal instantaneous relative velocity is:

Wherein difference representation node i, j is in the speed of current time t.

4. tentation data bag arrives node i now, and node j is one of neighbors of node i, and destination node is d.In network, the wireless coverage of each node is R, and two nodes to the range difference of destination node are:

ΔS _i,j(t)＝S _i,d(t)-S _j,d(t) (3)

5. in order to select effective next-hop node, first both candidate nodes needs to meet following formula, to guarantee that both candidate nodes is in the wireless coverage of present node.

R＞ΔS _i,j(t)·Rv _i,j(t)/c+ΔS _i,j(t) (4)

It is as follows that we define tolerance MDT (minimum duration time):

$\mathrm{MDT}=\underset{{k\∈N}_i}{\min }\left\{{\mathrm{MDT}}_k\right\}=\underset{{k\∈N}_i}{\min }\left\{\frac{\mathrm{\Δ}{S}_{k,d}\left(t\right)}{R{v}_{k,d}\left(t\right)}\right\},{\mathrm{MDT}}_k>0---\left(5\right)$

N wherein _iit is the neighbors collection of node i.Improve tolerance and not only considered the geographic distance of node, also considered internodal relative velocity simultaneously.Source node calculates the MDT value of each neighbor node, selects the minimum neighbors of MDT value as down hop forward node.This strategy is stablized more with reliable the next-hop node of selecting, thereby improves communication quality, more adapts to high air communications environment dynamically.

8., while running into route cavity in data forwarding process, adopt periphery ergodic algorithm as alternative in the reaction equation routing algorithm of AODV mono-class.The intermediate node of greedy retransmission failure is opened route finding process and is found an effective route entry arrival destination node, in the scope limiting, broadcasts RREQ routing request packet.When neighbors is received RREQ bag, first check the destination address of RREQ bag, if destination address is itself, produce and return a RREP routing reply bag; Otherwise, continue this RREQ of broadcast until arrive destination node.If do not find the path that arrives object within the time limiting, go off the air and abandon this bag.

9. once node is walked around hole region and is had in its neighbors than the node oneself with less MDT value, returns to greedy forward mode.

10. repeat above step, until complete data retransmission.

In sum, the joint route algorithm based on geographical location information has not only retained high efficiency and the simplicity of greedy forwarding strategies in geographical route, also combines with reaction equation route, sets up more effective and stable path.

Claims (1)

1. the simple and effective joint route algorithm based on geographical location information in aviation MANET AANET, is characterized in that adopting following steps:

A, suppose that all aircraft nodes have all been equipped with GPS navigation system, first node obtains required geographical location information, the position that comprises node self, one jumps the position of neighbors and the positional information of destination node, above information is respectively by GPS global positioning system, and beaconing mechanism and location-based service algorithm obtain;

B, this joint route algorithm have two kinds of mode of operations, comprise greedy forward mode and reaction equation route pattern;

First C, algorithm are operated in greedy forward mode, in order to select effective next-hop node, first both candidate nodes needs to meet following formula, to guarantee that both candidate nodes is in the wireless coverage of present node, wherein tentation data bag arrives node i now, and node j is one of neighbors of node i, and destination node is d, in network, the wireless coverage of each node is R, Δ S _i,j(t) be i, j is to the range difference of destination node, Rv _i,j(t) be internodal instantaneous relative velocity;

R＞ΔS _i,j(t)·Rv _i,j(t)/c+ΔS _i,j(t)

D, then in candidate's neighbors, according to the route metric MDT of new definition (minimum duration time), carry out data retransmission, by following formula, provided:

$\mathrm{MDT}=\underset{{k\∈N}_i}{\min }\left\{{\mathrm{MDT}}_k\right\}=\underset{{k\∈N}_i}{\min }\left\{\frac{\mathrm{\Δ}{S}_{k,d}\left(t\right)}{R{v}_{k,d}\left(t\right)}\right\},{\mathrm{MDT}}_k>0$

Wherein, N _ibe the neighbors collection of node i, this route metric considers position and the relative velocity of node, makes more efficient stable of forward-path;

E, when run into route when cavity in repeating process, route cavity does not exist than the node oneself with less MDT value in the neighbors of this node, now be switched to reaction equation route pattern, utilize RREQ/RREP mechanism find available path and carry out data retransmission, if can not find active path in limiting time, abandon this bag;

Once F node is walked around hole region, and exist than the node oneself with less MDT value in its neighbors, turn back to greedy forward mode;

G, repeat above step until complete data retransmission.